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THE

MICROGEAPHIC DICTIONARY.

O J o
THE MAINAED M. tiETCALF,

MICROGRAPHIC DICTIONARY;

A GUIDE TO THE EXAMINATION AND INVESTIGATION

OF THE

STRUCTURE AND NATURE

OF

MICROSCOPIC OBJECTS,

BY
J. W. GEIFFITH, M.D. &c.,

MF.MBEE OF THl*; ROYAL COLLEGE OF PHYSICIANS ;

ANU

ARTHUR HENFREY, F.R.S., F.L.S., &c.

PROFESSOR OF BOTANY IN KING's COLLEGE, LONDON.

FO UR TH EDITION.

EDITED BY

J. W. GRIFFITH, M.D. &c.,

ASSISTED BY

The Rev. M. J. BERKELEY, M.A., F.R.S., F.L.S.,

AND

T. RUPERT JONES, F.R.S., F.G.S.,

LATE PROFESSOR OP GEOLOGY, STAFF COLLEGE, SANDHURST.

ILLUSTRATED BY FIFTY-THREE PLATES AND EIGHT HUNDRED AND EIGHTEEN WOODCUTS

CONTAINING FIGURES OF 2680 OBJECTS.

VOL. I.— TEXT.

LONDON:
JOHN VAN VOORST, PATERNOSTER ROW.

MDCCCLXXXIII.

PRINTED BT TAYLOR AND FRANCIS,
RED LION COURT, ^LEET STREET.

ALEUE & PLAMMAAf.

/CTo^ "V-^o

\^

M. METOAlf ,

MICROGRAPHIC DICTIONARY.

Aberration.— The deviation of the

rajs of lijrht from the true focus of a lens or
cui'ved mirror, in consequence of which
they do not unite at a single point, but
form an indistinct or coloured image of an
object. It arises from two causes : the
form of the lens or mirror, when it is called
spherical aberration ; and the different re-
frangibihty of the rays of hght, when it is
called chromatic aberration.

ABROTHAL'LUS, Notaris and Tulasne.
— A genus of Lichens, Fam. Lichenacei,
remarkable for their parasitic habit and the
absence of a thallus. The species are now
referred to Lecidea.

A. Smithii (Welwitschii and microsper-
mus) = L. parineliamm.

A. oxi/spori's = L. oxysporus.

A. inquinans = L. inquiiians.

BiBLiOGEAPHY. Lindsay, Brit.Lich. 311 ;
Tidasue, Ann. Sc. Nat., Bot. xvii. p. 112,
1852 ; De Notaris, Mem. R.Acad. Sc .Turin,
X. p. 3-")l, 1859; Berkeley, Cryp. Bot. 405 ;
Leighton, Lichen-Flora, p. 384, 1879.

ACALETHJE (Medusa)).— An order of
Coelenterata, commonly Imown as Sea-net-
tles, on account of their producing urtica-
tion when touched ; or Jelly-fishes, or Sea-
blubbers, from their gelatinous consistence.

They consist of a transparent, floating
and free, discoid or spheroid body (hydro-
soma), often shaped like an umbrella ; and
vary in size from a mere speck to a yard in
diameter. Margin of the disk furnished
with filiform tentacles, cirri, &c. The
organs are radiate aroimd a longitudinal
axis, occupied by a central peduncle or
stalk (manubriuni), at the bottom of which
is the mouth. The disposition of the parts
is generally quaternary.

The cutaneous surface of the body, or
ectoderm, is covered Avith a very dehcate
epidermis (PI. 49. tig. 2). Cilia exist on
various parts of the body, especially the

Fig. 1.

Thaumantias hemisphaerica, magnified 2 diameters.

arms, tentacles, cirri, &c ; upon which also
peculiar stinging organs and organs of ad-
hesion occm*. In those species which are
notorious for their urticating powers, these
organs are also situated in aggregations be-
neath the epidermis of the body. The
stinging organs, or nematocysts, usually form
oval capsules, in which a spirally coiled
filament is enclosed (PI. 49. fig. 3 a, b) ;
this flies out on the slightest touch, with
the capsule to which it is attached, from the
irritated part of the slrin (I'l. 49. fig. 3 c).
In some Acalephpe, these stinging organs
are replaced by oval capsules from which a
rigid bristle projects (PI. 49. fig. 4). These
do not produce urtication, but enable the
animal to adhere to other bodies. Near
the surface of the body and between the
cells composing its substance, pigment-cells
frequently occur, some of which are isolated, .

39 79.'-)

ACALEPH^.

[ 2 ]

ACALEPH.E.

otliers aggregated into groups. The paler
and more delicate coloiu's are said to arise
in some instances from pigment uniformly
dissolved in the substance of tlie body ; it
is most probable, however, that they arise
from iridescence.

Muscular sr/sfem forming long, thin, reti-
cular fibres and bundles, almost everywhere
penading the contractile substance of the
body.

The floating and locomotion of these ani-
mals are often aided by larger or smaller
cavities filled with air.

The nervons system consists of a ring
following the margin of the disk, with
ganglionic expansions at intervals, giving
off branches to the tentacles and the radial
canals.

The orc/ans of sense consist of tubercular
or spathulate bodies situated near the mar-
gin of the body or at the base of the ten-
tacles, and connected with adjoiningganglia.
Some of these are regarded as organs of
vision (ocelli) ; and consist essentially of a
membranous capsule containing a clear
liquid with cr^-stals of carbonate of lime,
and sometimes a red or black pigTuent
(PI. 49. fig. 5 //). Those which contain no
pigment have been considered to be of
auditoiy function, and the crystalline bodies
otolithes. Some of them are protected by
an overhanging fold of membrane ; hence
the distinction of covered- and naked- eyed
Medusa- ; but the latter are now regarded as
the sexual zooids or gonophores of the
Ilydroida (THArMANTiAs).

The digestive cavity, which is situated in
the middle of the body, is lined with cili-
ated epithelium and furnished with distinct
walls (endoderm), which are directly con-
tinuous with the general parenchyma of the
body, so that there is no abdominal cavity.
The mouth is either single and central, or
multiple. In the former case, it is situated
at the end of the peduncle, in the middle of
the under side, and leads into a stomach,
which is frequently furnished with cacal
appendages. "When several oral apertures
are present, either several cesojdiageal canals
conduct the nutriment through the arms,
in which the oral apertures are placed, to a
central stt>mach, or each separate mouth
is connected with a distinct tubular sto-
mach. A distinct hepatic organ has not
yet been found. ]Jay Lankester dcscriles
the inception of natural food-materials in
the cells of the endodeim.

GastrovascuJar system. A number of

But there is no regvdar circu-

vessel-lilce canals run from the stomach or
central cavity throughout the body, the
principal branches forming rays from the
centre to the margin, communicating finally
with a circular vessel traver.~ing its circum-
ference (PL 49. fig. 5 d). These are also
Imed with cilia, and contain both the focd
and water
lation.

The Acalephae are propagated by the for-
mation of ova, and according to the plan of
alternation of generations. They are either
hermaphrodite or xmisexual.

The reproductive organs of the two sexes
are often so similar in colour, external form,
and arrangement, that they might easily
be mistaken for each other, without exami-
nation of their contents. They forni either
utricular or strap-shaped stripes, placed at
various parts of the body, often near the
rays of the gastrovascular system. In the
former case, the speiTuatic fiuid and the ova
are evacuated through distinct excretory
ducts ; in the latter, the spermatozoa and
ova escaping fi-om the strap-shaped testis
or ovary, pass directly outwards, or into
capacious cavities opening externally by
wide orifices. The ova are round, and sur-
rounded by a single very delicate capsule ;
and the genninal vesicle with its simple
germinal spot is visible through the whitish,
violet, or yellow yolks. The spermatozoa
move rapidly in, and are imaft'ected by
water ; thej are linear, or one end is
rormded, the other prulonged into a capil-
lary appendage (PI. ^9. fig. 5*).

The developmental metamorphosis of
some of the Acalepb.fe is very remarkable.
When the ordinary process of segmentation
of the entire yoUc is completed, the ova be-r
come converted into ovate infusoria-like
embryos or planida? (PI. 49. fig. 6), -\\ hich
revolve upon their longitudinal axis by
means of cihated epidermis, and swim about
like species of Levco}>hrys or Bursaria.
After a time, they become fixed at the
anterior extremity to some body; arms
then shoot cut from the imattached ex-
tremity, between which the mouth of the
polvpe-like animal (Hvdra-tuba state) is
developed (PI. 49. figs'. 7 & 8). At this
stage of development, the larvas multiply by
the foimation of gemmae (PI. 49. fig. 9 o),
and cffsets or stolons (PI. 49. fig. 9 h) ; and
ultimately each undergoes transverse di-
Aision, which takes place as follows: — the
larvse grow in length, and the body be-
comes constricted into several segments

ACA^'TIIACJLE.

[ 3 ]

ACANTHOMETRINA.

(PI. 40. fig. 10), from each of wliicb oiglit
bipartite processes shoot out in a -whorl
(Strobila-state). The segments of the body
then separate from each other seriatim, from
before backwards, swim about ^yith eight
rays (PI. 49. fig. 11), and at last become
gradually developed into perfect Medusaj.
Many of the JMi'dusfe are phosphorescent,
and render the sea luminous.

Gegenbaur divided a Thaumantias into a
hundred pieces, and found that each piece,
provided it contained a portion of the mar-
gin of the umbrella, grew into a perfect
small 31edusa.

Many of the organisms formerly con-
sidered Mechisce are now regarded as the
Medusoid buds or gonozoids of the Hy-
droida. See Thaumaxtias.

A small 3Iedi(sa, with 2 names : Craspeda-
ciistes Soicerhyi pm^Li mnocodimnVicfnria ^i&s
been found in the tropical fresh-water lily-
tank at the London Royal Botanic Gardens.
This ought to be the Medusoid gonophore
of a hydroid zoophyte !

BiBL. Eschscholtz, Sifst. d. Acal. Berlin,
18:?9; WiU, Horoi ten/est. ^'c, 1844;
Ehreuberg, Ahhandl. d. Bed. Ahad. 1835 ;
Art. AcaL, Todd's Cycl. (R. Jones) ; Sie-
bold, Lehr. d. J'erc/l. An. ; Pluxley, Inver-
tehrafa ; Lesson, Suites a Btiffon (Zooph.
Acfdfphes) ; Wagner, Icon. Zootom. ; Ge-
genbam-, Vergl. An at. 1878 ; Gosse, Mar.
Zool. ; Forbes, JVak.-ei/ed Medusrs (Ray
Sec); KoUiker, 7fo?2.^/.s?'o/'. I860; Haeckel,
Si/st. d. 3Iedi/s., 1879; Romanes, Plnl. Tr.
1876, p. 269 {Muse, syst.); Nicholson,
Zool, 1878; Pascoe, Zool. Class., 1880;
Kowalewsky, Ann. Nat. Hist. 1867, xx. 228;
R. Lankester, Qu. Mia: Jn. 1881, p. 119.

ACANTHA'CE^.— The seeds of many
genera of this family are clothed with hairs
composed of hygi'oscopic cells, containing
unreliable spiral fibres or detached rings.
Among these are Acantliodium s2ncatmri,J)e-
hle, Blepharis, and liueUia fvrinosa. Other
species and genera have the hygroscopic cells
destitute of internal fibre, as i??<cW« liitora-
lis, Flun/Jopsis ijlutinosa, Barleria noctijiora,
Lepidayatlds, ^-c. Fui1.her particulars re-
specting the hygroscopic cells will be found
mider Cell- jiEMBEA>'E and Spieal Stetjc-
lUEEs. See also Acaxthodium and
RuELLiA, and, for a similar phenomenon in
other families, Collomia, Cob^a, Salvia.

BiBL. Kippist, Linn. Trans, xix. p. 65.
■ ACANTHOCYS'TIS, Carter.— A genus
of Rhizopoda, apparently referable to the
Actinophryina.

Char. Rounded, green, with moveable
radiating spines and pseudopodia. Body
flexible, covered with minute fusiform
curved spicula ; spines straight, hollow,
bifid, discoid at base.

A. twfacea (PL 51. fig. 9), Found in
heath-bog water; diam. of body jjx".

BiBL. Carter, Ann. N. Hist. 1863, xii.
p. 263; Hertwig, .7«i. Zeitsch. (Qu.Mic.Jn.
1878, xviii. p. 2l)5).

ACANTHO'DIUM (Flowering Plants,
fam. Acanthacets). — Kippist first described
the curious hairs upon the seed of Acantho-
dimn sjncatum, Defile (PI. 28. fig. 24). The
entire surface of the seed is clothed with
hairs of whitish colour, appressed and closely
adherent in the dry state, being apparently
glued together at their extremities. When
placed in water, the hairs are set free and
spread out on all sides ; they are then seen
to consist of clusters of from five to twenty
sijiral cells firmly coherent below, but free
above and separating from the cluster at
different heights, expanding in all directions
like plumes, and forming a very beautiful
microscopic object. The free portions of
the cells elongate so as to separate the coils
of one, two, or occasionally three internal
spiral fibres, which are sometimes branched
and not unfrequently broken up into rings ;
at the lower pail of the cells the turns of
the spiral are connected by perpendicidar jiro-
cessessoas to convert the spiral into a reticu-
lated strnctm-e. See Spieal Steuctuees.

BiBL. Linn. Trans, xix. p, 65.

ACANTHOME'TR A, Miill.— A genus of

ACANTHOMETEINA.

ACANTHOMETRI'NA.— A family of
Radiolarian Rhizopoda.

Char. Body minute, spherical, capsular ;
traversed by numerous elongate, mostly
angular and hollow siliceous spines, which

meet in the centre. Between the

spines

pseudopodia radiate from the body (PL 51.
fig. 10), as in Adinophrys. Marine.

The body contains yellow globules, and
is sometimes covered with small spicules ;
and it is enveloped by a softer cortical sar-
codic mass.

The Acanthometrina, with the Polycys-
tina, have been rearranged by Hackel, in
his splendidly illustrated monograph, into
68 genera and 150 species.

They are found recent on the surface and
at the bottom of the sea, in the Mediterra-
nean, the Adriatic, and the North Sea.

They form beautiful microscopic objects.
See Radiolaeia.

B 2

ACAKTirorus

4 ]

ACARUS.

BiBL. Mliller, Ber. d. Bcrl. Ah. 1855,
p. 'J48; id. Ahh. d. Berl. Al: 1858, p. 1;
Hiifkel, liadiolar., 1802; Claparede and
Lachraann, Infns. p. 69.

ACAN'TIIOPUS, Vernet.— A g-emis of
Eiitomcistraca, Ord. O^tracoda, fain. Cytlie-
ridae. L^ke of Geneva.

l^iBL. Bibl. Univ. 1877 {Jii. Mic. Soc.
1878, p. 80).

ACA'REA. — A family of Aracbiiida, be-
longing to the order Acarina (Arach-
nida).

These animals are commonly called mites ;
and every one is famiJiar ^vith them as oc-
curring in cheese, sugar, flour, &:c. Some
also occur upon the skin of man and
animals, producing the itch and the
mange.

The parts of the mouth and the legs, upon
vrhich the characters are usually founcled,
may he best made out by crushing the ani-
mal upon a slide with a thin glass cover,
and washin"' awav the exudinfj stibstance
with water, as directed in the Article Pre-
PARATION ; sometimes hot solution of pot-
ash is requisite, with the subsequent addi-
tion of acetic acid and further washing.
AYhen afterwards dried and immersed in
Canada balsam, the various parts become
beautifully distinct, and may be perma-
nently preserved.

Acai-us (Tyror/hiphns), Body with a
transverse furrow between the 2ud and 8rd
pairs of legs ; legs nearly equal, all perfect,
and terminated by a membranous sucker or
claws, or both ; palpi adherent to the la-
bium (or lip).

Hypodera^. Body very long, legs very
short, and the 2 anterior and posterior pairs
far apart ; parasitic beneath the skins of
bu'ds.

Hypopus. Front pair of legs mostly
largely developed ; posterior almost atro-
phied. Parasitic on animals and plants.

Trichodactylu!^. Eostnnn (l)eak) short,
with minute bristles ; 4th pair of legs longer
than the rest, without claws, and terminated
by a very long bristle, the rest with 2 claws.
(Parasitic on Bees.)

P.<iorop)fcs. Body soft, depressed, spiny
beneath and at the base of the legs ; poste-
rior pair of legs small and rudimentary, the
rest with a claw and sucker ; body termi-
nated by two bristly projections. (Para-
sitic on the Plorse.)

Sarcopies. Body soft, transversely wrin-
kled, and with dorsal papilla? ; anterior
2 pairs of legs with suckt-rs, posterior ter-

minated by a long bristle, and without
suckers. (Parasitic.)

Uemodex. Body elongate ; cephalothorax
distinct from the ringed abdomen ; legs
terminated bv 4 or 5 very minute claws.

ACAKEL'LA, Kent.— A genus of In-
fusoria ; near Halteria. Kent, Man. Inf.
1880, p. 214.

AOAREL'LUS, Westwood.— A sup-
posed genus of Acarina. See Hypopus and
Phytoptida.

They seem to consist of larvae of Phy-
topti or species of Hypopus.

BiBL. Westwood, Proc. Entom. Soc. 1864,
p. 30, and 1870, p. 30 ; Tatera, Mon. Mic. Jn.
1872, viii. p. 2(33; Murrav, Econ. EnUmiol.
p. 246; Mclntire, M. Mic"^ Jn. 1874, xi. p. 1.

AOARPNA. — An order of Abachnida,

ACARUS, Linn. (Tyroy/yp/iMs). — A
genus of Arachnida, of the Order Acarina,
and family Acarea (see Abachxid.a. and
Acaeka).

The palpi adherent to the labium, the
perfect legs, and the transverse fiuTow dis-
tingidsh the genus.

Ac. domesticus, or siro (PI. 6. fig. 1), the
common Cheese-mite. Body oval, soft,
whitish, turgid and furnished with long
feathery hairs (b). The transverse fiurow
(c) occurs at about the anterior fourth of
the body ; and another is seen between the
head and the part corresponding to the
thorax. The head is susceptible of elevation
and depression.. In its natural state it
appears conical (r?), and is furnished with
two large mandibles ; these consist of a soft
retractile basal joint (e), and a second, di-
lated, non-retractile joint (/) resembhng
the fixed claw of a lobster, and a moveable
piece (/*) working against the latter. The
last two pieces are toothed where in contact
with each other. These mandibles can be
advanced separately or together, and be
separated or approximated. "Wlien in a
state of repose, they form as it were a roof
above the labium. The lal)ium (y) is quadri-
lateral, elongated, notched at the end, thin
anteriorly and in the middle, and consolida-
ted laterally with thi> palpi, which are 4- or
5-joiuted iyhh). The k'gs are reddish, in-
serted in two separate groups, but not very
far distant as in So rcoptes. The anterior
pair of legs are remarkable for their size in
the male, which is smaller and more active
than the female ; the third pair are the
shortest and smallest ; the third joint or
fcnnnr is larger and longer tlian those next
it; the sixth joint is long and thin; the

AOARUS.

[ •'-> ]

ACAIIUS.

seventh joint is fuvuislied with a cordifurm
membiauuus carunck', and a sino'lo simple
claw or hook ; rostrum and legs rcddisli.

This species is viviparous and oviparous,
and the eggs very numerous. The larvee
are hexapod.

These mites are very abiuidant upon old
cheese, ihe powder of which entirel}- consists
of them, with their eggs and excrement.

Ac. loiifiior. Body and hairs longer.
Found upon Gruvere and Dutch cheese
(PL 6. fig. -2). This is the so-called Ac.
Vrossii.

Ac. Sictdiis. With short legs. Found in
powdered Cantharides. Megnin, p. 14o ;
Murray, p. 274.

Ac. 7ni/coph(i(/us. Body long. Found
on mushrooms. Megnin, p. 143.

Ac. cntomopluKjus. Fomid in collections
of insects, of which it devours the body.
Megnin, p. 14-3 ; Murray, p. 263.

Ac. mcdus. On apple-trees in N. America.
Miu-ray, p. 275.

Ac. trctnslucims. On coffee-plants in
Oeylon. jNIurray, JJ. 27o.

Ac. bicaudatus. Abdomen furnished with
two pedif orm tubercles, beneath the base of
each of Avhich is a stigma. Found upon
the feathers of an ostrich.

Ac.fari'nce, same as A. domesticus. Found
in bad flour. DeGeer, Mem. vii. p. 97, pi.
15. tig. 15. {Ac.feculcs, found by myriads
in potatoes. Guerin-MeneviUe, Ann. N.
Hist. 1867, xix. p. 71.)

Ehizoglyphus (Claparede). Tarsi with
claws, but no suckers. Vegetable feeders.

li. echinojnis. In the bidbs of hyacinths.
Mui-rav, p. 257, fig.; Megnin, p. 144, fig.
49.

R. p1tylloxer(S. On vine-roots. Murray,
p. 258.

M. Robinii. On potatoes, dahlia, and
hyacinths. Murray, p. 259.

R. rostroscrndus. On decaying mush-
rooms. Murray, p. 2G0.

Serrator (]\It5gnin). Mandibles strongly
serrate ; a hook, but no caruncle.

8. amphibius. In decomposing mush-
rooms. Megnin, p. 144, fig. 50.

Ac. Bysenterke. Nyander, Amocnit. Acad.
V. p. 97 ; Limi. Gmel. p. 2929. Foimd in
the dejections of dj-sentery ; also in old
casks.

Ac. passerinus. Found upon young
birds. DeGeer, vol. vii. 139. Ac. chdopus,
Herm. Mem. Apterol. p. 82, pi. 3. fig. 7.

Ac. (Carpor//yphi(s) pasHHlarum. With
two very long buccal bristles; fives upon

dried figs, and other saccharine fruits,
llering. Nova Acta, xviii. p. 618, pi. 45. f . 14,
15 ; Megnin, p. 141.

(ih/viphayus (llering). Body soft, not
di\ided into two parts by a transverse line
or furrow, but with a dorsal depression,
and an anal projection ; legs perfect, with
acetabida ; hairs feather}'.

A. i^Gl.) pnmorum. Found on dried
plums ; produces the grocer's itch. Hering,
Nova Acta, xviii. p. 619. pi. 45. f, 16, 17 ;
Murray, p. 278, fig.

A. {Gl.) hippopodos. Body as broad as
long, very acute anteriorly, entirely covered
with short hairs ; a minute projection at
the end of the abdomen. On tdcers of
horses' feet. Tiering, Nov. Act. xviii. p. 607 ;
Murray, p. 279, fig. An undescribed
Acarus has also been mentioned as occurring
upon the feet of sheep aflected with the
canker. Groguier, Zool. veter. p. 233.

A, {Gl.} hericius. Found on weeping
rdcors of ehns. Robin, Joicrn. d. V Anat.
1808, p. 603.

A. {Gl.) cursor. Found in the feathers
of the owl and in the cavities of the bones
of skeletons. The hairs are jointed. Ger-
vais, Ann. Sc. Nat. 2 ser. xv. p. 18, pi. 2.
f . 5 a ; Murray, p. 278, tig.

A. (Gl.) spinipes. Like G. cursor, but
smaller ; the anal appendage short. Frem,
& Rob. Jn. Anat. 1867 ; Murray, p. 281,
fig.

A. (Gl.)bal(snarum. On whales. Murray,
p. 282, fig. _

G. pliimiger. "With strongly feathery
hairs. In cellar-dust, stables, &c. Murray,
p. 283, fig. A beautiful object.

G. palmifer, SmaUer than the chee.'-e
mite ; hairs leaf-like ; body granular.
Murray, p. 284, figs. Found with the
last.

A. {Gl.) {Surcoptes) palumhiniis. On the
pigeon. Koch, I. c. fasc. 5. pi. 12 ; Robert-
son, Qu. Micr. Jn. 1866, p. 201.

Some other species have been insuffici-
ently examined : —

Ac. aviculuniin, DeGeer, Mem, vii. 100.
pi. 6. fig. 9. Louse of the grouse. Lyouet,
Mem. Mus. xviii. 281. pi. 15. f. 10.

Ac. marilce, Gervais, Diet. Sc, Nat. Suppl.
i. 45.

Ac. favorum. Found in old honeycombs,
Herm. Mem. Apterol. p. 86,

Ac.funyi, Herm. /. c.

Myobia (Heyden). B(jdy elongate, many-
lobed; rostrum styliform.

M, musculinus, Schrauck, p. 501^ pi. I.

ACAULON.

[ 6 ]

ACHETA.

f. 5. Snrcoptes muse, Koch, Crust. iS-c.
f asc. 5. pi. 13 ; Ou the mouse, Murray, p. 315.
Hypopus. See llvpoi'us.
A destructive disease in the sugar-cane is
caused in various parts of the world by a
minute red Acarus, which swarms round
the stem.

BiBL. Dup-es, Ann. d. Sc. Xaf. 2 ser. ii.
p. 40 ; Koch, Deutschl. Crust. ; Walckenaor,
Apteres, 3 (Gervais) ; Fiuuouze and Eobin,
Journ. d. VAnut. I<s67, oOo, oOl ; Buisduval,
L'Untomol. hurticole, p. 76 ; 3Iic. Soc.
Jn. l>i80,Gl>/c. dev. p. 249; Murray, ^c.^«^.
1880 ; Meo-nin, Parasites, 1880.

AOAU'LON, C. Midler.— A genus of
Phascacete (Acrocarpous Mosses), taken as
a section of Phascum by Wilson. A. muti-
cam is common on mnist banks.

BiBL. Mliller, Syno]>s. Mtisc. i. p. 21 ;
Wilson, Bryol. Brit p. 20.

ACEPH'ALOOYSTS.— A term used to
denote certain simple sacs filled with a trans-
parent liquid, found in the bodies of ani-
mals, and usually known as Hydatids by
pathologists. They were formerly regarded
as distinct parasitic animals ; but recent
observations show that they often consist of
the cysts or larval forms of cestoid Entozoa.
The cysts in many cases contain at first
only an amorphous substance or a liquid.
At a later period their real nature is deter-
mined by the presence of the included
Echinococcus — head and hooks. The .sacs
or vesicles are oval or spherical, and vary
in size from a pin's to a child's head. The
walls of the sacs vary in thickness and
transparence. They present no appearance
of either head or body. In the larger cysts
the walls are distinctly laminated. They
exhibit no fibrous structure, but appear
composed of a homogeneous substance
closely resembling albumen in properties.
Two species have been distinguished : —

A. oidof/om (socialis vel jiro/ifcra), the
pill-box liydatid of Hunter. This is met
with in the liver, kidney, ovary, testis, and
caA'ity of the abdomen. When developed
in the substance of an organ, it is always
enveloped by areolar tissue. The secondary
cysts are detached from the inner surface of
the parent.

A. cx(uiena : in this the progeny is de-
veloped from the outer surface ; found in
the ox and other dometic animals.

In the examination of cysts supposed to
be hydatids, careful search should be made
for the hooks of ErhinococcKs or Ci/sticcrcus
which can frequently be found when no

further remains of the body are distinguish-
able. The hooks are figured in PI. 21.
tig. lb. See E.xtozoa and Echinococ-
cus-.

ACERVULI'NA. Schultze.— Under this
name Schultze, in 1854, grouped as a genus
some of the adherent varieties of Planorhn-
lina variabilis, D'Orb., that have an irregular
growth, with heaped chambers. They are
found in Avarm .seas, attached to algfe and
other bodies. The word " acervnliue " is
applied to any such wildly aggregated
growth in Foramiuifera.

BtBL. Schultze, Orf/anism. Polythal. 67 ;
Carpenter, P'oram. 200.

ACETIC ACID.— This is the well-
known acid of vinegar.

It occurs in the juice of the flesh of ani-
mals ; sometimes in the stomach in indiges-
tion ; also in the human blood after the use
of alcoholic liquors, and in that of animals
whose food has been soaked in spirit. It is
also a common product of the decomposition
of vegetable substances, both by fermenta-
tion, and in distillation, as well as a com-
ponent of the natm-al plants, mostly com-
bined with lime or potash ; it is also a rare
constituent of some mineral waters.

The only salt of this acid requiring men-
tion is the acetate of copper (neutral), which
is made by dissolving common verdigris in
excess of dilute acetic acid, filtering and
crystallizing upon the slides. The crystals,
when mounted -in Canada baUam, exhibit
well the phenomena of dichroism. PL 30.
fig. 2.

Acetic acid is one of the most connnon
and valuable micro-chemical reagents. It
is particularly useful on account of its action
upon animal cells in general, rendering the
cell-walls transparent aud the nuclei more
distinct. The ordinary strong acid (sp. gr.
1044) should be used.

ACETEXOP'SIS, Kent.— A genus of Eu-
fusoria, familv Ophrvodendrid;i3.

BiBL. Kent, Man. Infus. 1880.

ACIIAPtAD'RIA, Wright.— A genus of
Ilydroid Zoophytes.

A. larynx resembles in habit Tiihularia
larynx ; polypes orange. Marine ; on stones.

i3iBL. Str. Wright, Qu. Mic. Jn. 186-5,
iii. p. 50 ; Ilincks, Brit. Zoopln/t. p. 133.

ACIIE'TA.— A genus of Ort'hopterous in-
sects, one species of which, A. domestica, the
house-cricket, is familiar to every one. The
general structure of this insect agrees so
closely with that of Blatta oricntalis, the
common cockroach or black beetle, which is

ACPILYA.

[ 7 ]

AOIILYA.

described at some lenjrtli, that it requires no
special iicitice here. (See Blatta.) Some
parts of the internal structure of the cricket
are very beautifid, as the tongue (PI. 33.
fig-. 23), the o-izzard (PL 34. tig-. 1), and the
ear in the fore legs (PI. 34. tig. 71/). These,
as also the curious mechanism by which the
chirping noise of the male is produced, are
described under Insects.

ACH'LYA, Nees (»SV//;/-o/t'_(/w/a,Kutzing-).
— Remarkable microscopic plants,sometimes
referred to the Algae, but more properly
belonging- to Fungi. Cienkowski has re-
cently confirmed the idea formerly enter-
tained, that Ach/i/a is an aquatic form of
the Mucoriuous Fungus called Sporendo-
NEMA Muscce (Einpusa Muscco, Cohn), the
common tiy-fungus. Cohn and Al. Braim
deny the identity, while Berkeley thinks
Aclihja may be an aquatic form of Botrytis
Bassiana. They are found growing para-
sitically upon the bodies of dead files lying-
in water, also upon fish — as salmon, salmon-
eggs, frogs, &c., and in some cases upon de-
caying plants. To the naked eye they ap-
pear like colourless minutely filamentous
tufts, adherent to such objects, forming a
kind of gelatinous cloud more or less en-
Teloping- them. When placed beneath the
microscope, the tufts are seen to con.sist of
long, colourless, tubular filaments, spreading
out in all directions, with or without lateral
branches ; these erect filaments arise from
a kind of mycelium of ramified filaments
hdng upon the object upon which the plant
grows. The erect filaments are devoid of
septa, narrowed upwards, and vary in thick-
ness, being usually of smallest diameter in
those cases where they are closely crowded;
the ordinary thickness varies from 1-lOUU to
1-350 of an inch. The tubes contain a colour-
less slightly granular protoplasm, which
is denser on the walls ; and these sometimes
exhibit an irregular spiral arrangement of
the granules ; the granules are seen to move
slowly in anastomosing currents running in
various directions, exhibiting, that is, the
well-known phenomenon of the circulation
of cell-contents, such as is met with in the
hau's of Tradescantia, &c. The walls of the
tubes are coloured blue by iodine and sul-
phuric acid, therefore consist of celhdose ;
the contents are nitrogenous, taking a bright
yellowish brown with iodine ; no trace of
starch or chlorophyll can be detected in the
cell-contents in this stage, whence these
plants are regarded by some authors as
-''ungi ; but, as mentioned hereafter, Prings-

heim states that their ripe spores do con-
tain starch.

Kiitzing describes a number of species of
this genus, under the name of Saproleynia,
while a recent observer, Piingsheim, regaids
them all as forms produced by varying ex-
ternal conditions. A. de Bary separates
Achlya prolifera, Nees, from Saprolcijnia
ferax, Kiitzing, referring to the former the
Saproleyiiia ferax of Cams and the Hapro-
lc(jnia capituUfera of Ak'X. Braun, to the
latter the Achlya pruUfera of Cams, and,
doubtfully, the >S'. molluscornm of Nees and
Gruithuisen. The distinction between these
is said to lie in the details of the formation
and emission of the active gonidia or zoo-
spores; but we cannot make out satisfactory
dilferences.

The following details respecting the for-
mation of the active gonidia and the resting
spores are given at length on account of
their well illustrating modifications of free-
cell formation. In about thirty-six huurs
after the appearance of a specimen on any
body, the apices of the erect tdaments
exhibit remarkable changes. The granular
protoplasm, which at first is equally dif-
fused throughout the tube, only densest
where it lies on the wall, increases in quan-
tity and " travels up " into the end of the
tube, becoming accumulated there, giving
it a brownish colour and at the same time
causing its distention, so that the upper part
of the tube acquires a clavate form, rouiided
off above. A sharp lirie of demarcation is
soon formed by the di^ i.sion of the primor-
dial utricle, followed by the production t f a
septum, which shuts ofi'this clavate joint as
the sporange ; and a little projecting pouch
or beak is developed at the summit, or
sometimes a little below this on one side.
The contents,becoming- still more condensed,
again apply themselves as a tliick invest-
ment on the wall, leaving a lighter spaco
in the middle of the cavity. luequalitie.-, or
nodular protuberances, are soon observable
in this layer ; and it speedil)' becomes broken
up into numerous little isolated , portions,
individualization of these commencing at
the summit of the sporange and becoming
completed gradually from above doAvuwards.
The end-cell is now a clavate sporange filled
with numerous polyhedral or globular new
"piimordial cells," in the development of
which from the contents of the general
parent-cell no trace of nuclei or " special
parent-cells " can be detected ; their size is
about 1-2700 of an inch; and they have

ACriLYA.

[ 8 ]

ACHLYA.

clearly defined outlines, but are stiU con-
nected together by a gelatinous substance in
■wliicb they are completely imbedded. These
secondary cells then become retracted from
the walls, and accumulate in a dense, rather
confused looking mass in the centre of the
sporange ; endosmose of water through the
now bare ceUidose wall of the sporange
seems to exert a pressure upon them,and also
on the wall itself, whicli finally bursts at the
process or beak mentioned above, and the
secondary cells nearest the opening are shot
out with some force, the rest following, but
gradually more qidetly. There is no inde-
pendent motion of the contents, or j erking
of the secondary cells, before this emission
of the latter ; on the contrary', while in the

Fig. 1*

Achlya prolifera, discharging its zonsporps: the lower
zoospores treated with iodine ; magnified 400 diameters.

sporange, they adhere so closely that their
shape is scarcely distinguishable, and it is
only when the greater portion have escaped
that it is iierceived that the pressure had
caused them to assume a spindle-shape. As
the emission of the secondary ceUs goes on,
those escaping first are only removed so far

as to make room for their successors, and
the whole remain adherent together as a
globidar mass or " capitidum " seated on the
apex of the sporange ; they reassume, more
or less completely, the spherical form, by
degrees, after they have escaped from the
sporange : those w'hich can expand freely
become globular; those pressed upon by their
fellows become polyhedral. At the time
of emission, these secondary cells exhibit a
double line at the circumference, which
seems to indicate the thickness of the pri-
mordial utricle. Soon after the expulsion
another deUcate line is detected external to
these ; and this indicates a newly produced
envelope, which becomes thicker with age,
and after a certain time can be 'coloured
blue by sulphuric acid and iodine, which
demonstrates its composition of cellulose.
Application of a strong acid is necessary for
this purpose.

The globular head of secondary cells
remains for two or three hours attached
upon the summit of the empty, colourless
sporange. Then these minute cells emit
their contents by a lateral orifice, giving
origin, each of them, to a zoospore or active
gonidivmi. Neither the motion nor the
appearance of cilia follows the expulsion im-
mediately, but takes place after the gunidia
have increased somewhat in size and ac-
quired an ovate form. The duration of the
motion lasts from a few seconds to a few
minutes, after which the gonidium sinks to
rest and begins to germinate. The gonidia
possess no cellulose membrane while in
motion, but acquire one when they come to
rest and germinate. The cilia are two, and
arise fi'om the point which first emerged
from the parent vesicle, and which at all
periods exhibited a lighter tint, indicating
a vacuole in the protoplasmic mass. If
the expulsion of the gonidia is prevented
(as occurs sometimes when the plant is kept
under the pressure of a glass slide, in too
httle water, in microscopic investigation
of it), the gonidia germinate within their
ceU-membraues, wliich, instead of dis-
charging active zoospores, emit germinating
prolongations, just like those issuing from
the single germinating gomdia. These spread
out here in all directions from the globular
capitvlmn, still seated on the end of the
sporange.

During the formation of these sporanges
and the gonidia, after the septum has been
completed, the tube sends out lateral
branches from just below it, which some-

ACHLYA.

[ 9 ]

ACriNANTIIES.

times equal the sporaoge in length by the
time the latter discharges its contents; then
this branch becomes developed as a spo-
range, either at its summit or in its whole
length, or, when the branch is very short,
the portion of the maiu tube below the first
septum becomes a sporange. Sporauges of
a third rank may succeed to those of the
second rank, and so on, until the plant has
exhausted the supply of food at its service.
In another form the active gonidia are pro-
duced at once in the sporanges, without the
intervention of secondary cells ; and then
they begin to move even before leaving the
parent sac.

Achlya prolifera also produces, though
more rarely, globular ur spindle-shaped spo-
ranges, either terminal or borne on special
short lateral branches, in which are deve-
loped resting spores, characterized by a
larger size, double cell-membrane, and by
the absence of the cilia and consequent
motion. The mode of their development is
similar to that of the active gonidia ; but
they are much fewer in number, sometimes
as many as twenty, sometimes only four,
three, two, or even one being present in a
sporange. When a number occur in a
sjnndle-shaped sporange, they are ranged in
two rows, alternately, so that each is par-
tially interposed between its two opposite
neighbours. Their diameter varies from
1-1250 to 1-750 of an inch, the colour brown-
ish, displaying numerous oil-drops in the
granidar contents when mature. The spo-
ranges producing them display a number of
round orifices when the spores are ripe ; but
the spores appear to escape by the decay of
the walls. These resting spores may remain
unchanged in water for a long time when no
suitable nidus exists, but will quickly ger-
minate if a dead insect or similar object be
thro%vn in.

The resting spores are from 1 to 20, while
the active gonidia are from 6 to 150, the
nimiber depending in each case on the size
of the sporange, not upon the size of the
spores or gonidia, which is tolerably regular.
Pringsheim states that starch occurs in
the contents of the resting spores of >S'.
ferax.

A third form of reproductive organ is
described by Cienkowski, which in the
earlier stages resembles a sporange of I'est-
ing spores ; but the spores produce each a
long tubular neck, which bores through the
wall of the sporange and discharges its con-
tents as minute swarming bodies into the

water; these have not been seen to germi-
nate. These Hask-shaped bodies resemble
the formations seen by Carter in Spiro-
GYEA ; and we have seen them in other
Algaj. Al. Braun at first described them
as a species of Chyteidium, but subse-
quently has expressed an inclination to
regard them as antheridial spores of
Achlya.

In addition to the above, Al. Braun has
described curled tubular processes, resem-
bling the horns of Vaucheria, associated with
the sporauges in which resting spores are
formed; and he is incUned to regard them
as antheridia exercising a fecundating oihce,
hke the horns of Vaucheria. Similar bodies
have been recorded in other Sapyoleynice,
especially in Achlya cornuta. (See PL 27.
figs. 22-27).

A. lignicola is found upon wood in water.

BiBL. A description of the supposed species
-svill be found in Kiitzing's Sp. Algarum,
p. 159. For further information on the de-
velopment, see AJ. Braun's Rejuven. {Ray
Society, 185.3, pp. 188, 268) ; Pringsheim,
Nova Acta, xxiii. pt. 1. p. 307-460, 1852 ;
Anton de Bary, But. Zeit. x. p. 473, 1852 ;
linger, JUnncsa, 1843, p. 129 {A7in. d. Sc.
Nat. ?j^^ ser. ii. p. 5. pi. 1, 1844); Meyen,
Pflcmzenphys. iii. 457 ; Nao-eli, Zeitschr.flir
Wis. Bot. heft 1, p. 102, heft 3, 4, p. 28
{Ray Soc. 1845, p. 278, 1849, p. 101) ; Thu-
ret, Ann. d. Sc. Nat. 3™** ser. t. xiv. p. 20,
p. xxii, 1851 ; Ch. Robin, Vcyet. Paras. 2nd
edit. 1853, p. 372 ; Varley, Tr. Mic. Soc.
iii. ; Cienkowski, Bot. Zeit. xiii. p. 801 ; Al.
Braun, Chytridimn, Abh. Berlin. Ak. 1855 ;
Verjilny. iii d. Natur, p. 318 (Ray Society,
1853, p. 298). A Hst of all the writers who
had treated of Achlya before 1843 is sub-
joined to Unger's Essay in the Linnaa ;
Pringsheim, Jakrh. Bd. 1. heft 2, bd. 2. heft
2; Archer, Qu. Mic. Jn. 1867, p. 120;
Sachs,^o^. 1874, p. 276 ; Pfitzer, Monatsber.
d. Berl. Akad. Mai 1872 ; Grevillea, March
1878 (woodcuts).

ACHNANTIIES, Bory.— A genus of
Diatomaceee (Cohort Achnanthefe).

Char. Frustules compressed ; either sin-
gle, in pairs, or united into a straight fila-
ment ; geniculate in front view, without
septa ; attached by a stipes fixed to one an-
gle ; uppermost valve with a longitudinal
median line, lowermost with a longitudinal
line, and a median nodule or stauros.

The individual frustule, when single, or
the lowermost when they are united, is
furnished with a stipes or stalk, arising

ACHNANTHIDirJM.

[ 10 ]

ACHORION.

from one end of the lower margin. Side
view of frustules elliptical, oblong or limnir,
sometimes slightly constricted in the mid-
dle ; markings of upper and lower valves
ditlerent, the upper (PL IG. fig. 2) exhibit-
ing transverse rows of dots (appearing like
striaj under a low power) interrupted by a
longitiulinal line, the lower (PI. 16. fig. 3)
being also furnished with transverse rows
of dots, interiupted by a stauros, as also by
a longitudinal line which in some has a no-
dule at each end. The valves being much
compressed, the transverse rows of dots ap-
pear also in the front view. The hoops
exhibit faint longitudinal and sometimes
transverse striae.

Achnnnthes resembles Striafella in its
stalked flag-like filaments, but may be known
from it by the absence of internal siliceous
plates or vitta3.

Species : —

Freshwater; markings faint (minute) A.exilis*.
Marine or brackish water; markings
di-itinut.

Stipes longer than frustnles A. lonffipes^.

Stipes shorler than iVustules.

Ends of valves acute A. brevipes.

Ends of valves obtuse A. subsessilis,

* PI. 16. fig. 4. t PI. 16. fig. 1.

Kiitzing enumerates 15 species oi Ach-
nanlhes.

BiBL. Ralfs, Ann. N. Hist. xiii. 489;
Kiitzing, Bacill. p. 75, & Sp. Alg. p. 54 ;
Smith, Brit. Dial. ii. 25 ; Eabeuhorst, Fl.
Alq. 109.

ACIIXANTIIIDIUM, Kiitz.— A genus
of Diatomacete (Cohort Achnanthea^).

Char. Those of Achnanthes, mostly tin-
gle, and Avithout the stipes.

Five British species ; freshwater : —

Filament of numerous frustules ... A. lauceolatum.
Fru^tulcs few, valves constricted

in middle A. coarcialum.

Frustules few, often straight; valves

einstricted ue.arthe end A. microcephalum* .

Frustules few; valves obtuse, ua-

coustricted A. lineare.

Frustules few, median line sigmoid A.JIexeUum^.

* PI. 16. %. 5. t PI. 1<3- i!g- t5.

Frustules very small, and markings very
faint.

BiiiL. Smith, Brit. Diat. ii. 30 ; Kiitzing,
Bacill. 75, & Sp. AI(/. 5."}.

ACIIO'lilOX, I.'ink and Komak.— The
generic name applied to one of the vegeta-
bles occurring in Fams, and characteristic
of that disease of the skin (also called
Porriyo or Tiiieci favosa). The structure of
the plant, Achorion Schoenleinii, bears
much resemblance to that of the genus

Torula ; but it occui-s in definitely bounded
patches having a special arrangement of
the microscopic elements of which it la
constituted.

Much has been written by medical authors
regarding these bodies ; but we shall not
enter into this part of tlie subject here, fur-
ther than to state that the presence of this
vegetable structure seems to be essential
and causative in the disease of the skin to
which we have alluded. Remak was unable
to make any of the spores germinate in or
on animal substances ; some however emit-
ted prolongations when placed upon an
apple; but the surface then decayed and
turned brown -watliin the week, and became
covered with mildew (Peuicillium f/laucum) .
One of the entire corpuscles kept upon the
arm for several days, fell off without leaving
any mark; but a fortnight after a /Vav/^ began
to be developed. Gruby states that he inocu-
lated various parts of the body with it, and
even caused it to grow upon wood(?). Ben-
nett ultimately confirmed the statements of
Gruby as to the inoculation.

-Unfortunately, most authors who have
written on the parasitic fungi which occur
in morbid conditions of the human frame,
or are productive of disease, have not been
well acquainted with either Fungi or Algse.
Numberless names have been assigned to
them ; and in consequence, while many of
these organisms have been considered Al-
gfe, they have been regarded by others as
Fungi. It is, however, probable that all of
them are mere conditions of the most uni-
versally difYused species of Pcnivillium, As-
pcrf/illits, Jl/icor, or Cladosporium — genera
which are ca])able of propagation by cells
thrown off from the threads, other tlian the
norn)al fruit. It is quite impossible that,
as supposed by Ardsten, such a genus as
Fuccinia could be produced on animal
tissues.

BiBL. Ch. Robin, Vcf/. parasites, 1853,
(plates, 2nd edit.) ; Bennett, Month. Jn.
Med. Sc. 1850 (tigs.), and Tr. Boy. Sac.
Edinh. 1842, XV. pp. 227-294; Gruby,
Compt. Bend. 1841, xiii. p. 72; Mycodermes
8^c., ihid.. o09 ; Tinea favosa, Midler's Ar-
chiv, 1842, p. 22; Hannover, MiUIer's Arch.
1842, p; 281-295, pi. 15. hgs. 7-9; Miiller
and Retzius, Midi. Archiv, 1842, p. 192, pi.
8 and 9 ; Lebert, Phi/. Path. ii. p. 477, Paris,
1845 ; Reniak-, Diaqn. u. pathoqen. Unters.
Berlin, 1845,p. 193-215 ; Bazin,"Zes Teiqnes,
Paris, 1853, 8vo (plates) ; Robin, Micr.
1877, p. 8(30.

ACHROMATISM.

[ 11

ACHRO'MATISM. — A term properly
sig-nifyiujr freeclt)iu I'roiu cliromatie aber-
ralion, but commonly used to denote free-
dom from both spherical aud chromatic
aberration.

A CIC LTL A'RIA, D' Archiac— One of the
Foraminifera imperforata, related to Dac-
tyhpuru, aud consisting- of numerous cham-
bers arranged in close order side by side
without intercommunication, and forming
minute aciculate cylinders, or narrow ta-
pering plates. Known fossil only in some
Tertiary beds of France.

BiBL. Carpenter, Introcl. For am. 137.

ACIXE' RIA, Duj . — A genus of Infusoria,
of the family Trichodiiiia.

Char, Body oblong or lanceolate, de-
pressed, the i'ore part somewhat obUquely
recurved like the blade of a sabre ; a row of
cilia,directed foiwavds, arisingfrom one side.

Dillers from Traclidius, Buj., in the ar-
rangement of the cilia aud in the anterior
curvature; devoid of a mouth, like Trache-
lius, Avhich especially distinguishes the pre-
sent genus from Pclecida. "2 species :

A^ incurvata (PI. 30. fig. 1) ; marine,
colourless ; length 1-590 inch.

A. acuta (PL 30. fig. 2), found in fresh
water ; length 1-580 inch.

Bujardiu figures in the latter species cilia
upon both margins, those on one side being
directed forwards, and those on the other
backwards.

Claparede and Lachmann refer these to
Amphileptus,

BiBL. Dujardin, /ji/«s. p. 402; Clap, and
Lachm. Inf. p. 356.

ACINETA, Ehr.— A genus of Rhizo-
poda, belonging to the family Aciuetina.

Claparede aud Lachmann enumerate 8
species.

A. iwjstacina (PL 51. fig. 11). Yellowi-h
brown, rounded, tentacles in two bundles ;
1-120 to 1-800. On Lcmna minor.

A. patida (PL 51. fig. 12). Body as if
resting on a cup-shaped carapace, variable
in form; contains brown granules. On
marine AlgiB. Norwav. Length 1-100".

A. iuherosa (PL 30. 'fig. 4). Colourless
or yellowish brown, triangular wlien ex-
panded; tentacles arising from the distal
angles only. Salt or brackioh waters; 1-lCO"
to 1-410".

A. Lyncjhyi, fcrrum-equinum, and cylin-
drica are referied by Ci. aud Lachm. to
Podophrija.

A. Notoncdee. On the hairs of the legs of
N. glauca.

] ACINETINA.

BiBL. Vmcmi,Ann. d. Sc. Nat. 3 s^r. Zool.
iii. & ix. ; Ehr. Inf.; Duj. Inf.; Claparede
and Laelimann, I^tiidex, ^-c. ; Ann. N. II.
1857, xix. ; Stein, Infm.; Cegenbaur,
3Iorph. Jaln-h. 1875.

ACINETI'NA, Ehr.— A family of Radio-
larian Rliizopoda.

Char. Those of the Actinopliryina, but
with usually capitate aud suctorial tubular
tentacles, the body being more or less en-
closed in a carapace, which is generally
prolonged to form a stalk.

The structure and relations of these ani-
mals are still very unsettled. The re-
searches of Pineau and Stein tended to
render the existence of the species doubtful,
by showing that they were stages of deve-
lopment of Episti/lis, Va(/inicola, Vorticella,
&c. ; but this has since been found to be in-
correct. They exliibit a nucleus, and one
or more contractile vesicles. The remark-
able suctorial character of the tentacles has
not been proved to occur in all the genera
and species. Many, however, have been
seen to take food voraciously, which is thus
effected : when an Infusorium touches the
button-like end of the tentacle, it usually
remains adherent to it ; the end becomes still
more dilated so as to constitute a sucking
disk, and the ray becomes thicker and
shorter, the other rays at the same time
making grasping movements and endea-
vouring to attach their extremities to the
captured prey. A current of chyme-par-
ticles is then soon seen running from the
captured infusorium into the body of the
Acineta. The chyme-particles form at first
a slender row,but afterwards collect in a drop.
The body of the Acineta then becomes
opaque, from the collection of the drops.

The colourless or coloured ova described
by Ehreuberg ai'e partly chyme-particles,
partly oil drop-like globules which make
their appearance in the Acindcs after ani-
mal food. The ciliated swarm-germs to
which they give origin have been traced
directly into .Acinetce. Fission has been
observed in Acineta vii/stacina, not in the
others. The genera may be thus divided :

*Tt'ntaele9 not borne upon a proboscis.
Tentacles unbranched.
Stalks simple.

fA peduncle 1. Podophriia.

Ko shell < Xo pedun- (free.. 2. Sphrrophrya.
\_ cle ) fixed. 3. Trichophrj/a.]

A sh >n (Pfli'ic'p present. 4. Acineta.

'"' ") Peduncle absent... 5. Solenophri/a.

Ftalka branched 6. Dendrosoma.

Tentacles branched 7. Dendromycetes.

**Tentacles borne on a long pro-
boscis 8. Ophryodendrion.

ACOMIA.

[ 12 ]

ACROSTALAGMUS.

Here belong, perhaps, the genera Core-
thria, Ephelota, and Zooteira (Wright) ; and
Alder's animalcules.

ACO'MIA, Du]. — A genus of Infusoria,
of the family Euchelia.

Char. Body oblong-ovate or irregular,
colourless or granular, turbid, composed of
a glutinous homogeneous substance con-
taining irregular granules, and ciliated only
or principally at one end. Dujardiu de-
sci'ibes eight species, to which Perty adds
one.

Marine, or inhabiting decomposing in-
fusions. Minute and colourless.

A. vitrea (PI. 80. fig. 3) ; freshwater ;
length 1-808.

BiBL. Duj. Infiis. p. 382 J Perty, Zur
Kenntiiiss, i^'c. p. 149.

ACONTIOPH'ORUS, Brady. A genus
of Eutomostraca, Ord. Copepoda.

A. scutatus and A. annatus ; marine ;
around the British coasts.

BiBL. Bradv, Copepoda {Ray Soc), 3. p. 69.

ACPtEMO'NIUM, Link— A geuiis of
H}-phomycetous Fungi, belonging to the
division Mucedines ; distinguished by its
jointed threads bearing numerous patent
branchlets, each of which is terminated by

Fie:. 2

Acremonium fuseum (magnified).

a single globose spore. Perhaps only states
of some other genus. British species :

A. verticiUatum, Link. On dead wood,
trunks of trees.

A. alternatum, Link,
leaves.

A. fuscmn, Schmidt (lig.
wood and sticks.

A. ra/ufienum, B. and Br.
Distinguished by tlie threads being matted
together below into a distinct stem.

BiBL. Enril Flora, v. pt. 2. p. 347;
Greville, .W«. Cryp. Fl. 1. 124. figs, land 2;
Berk, and lb-. Ami. N. Hist. 1871,. Tune.

AC1I()CA1^'PI.— Anartiticialdivisionof
Mosses (see Mosses).

ACllO'PElltLS.—A genus of Eutomos-
traca, of the family Lyuceidse (Baird).

On decaying
2). On dead
On dead frofj-s.

Char. Shell somewhat harp-shaped, the
anterior inferior margin projecting and ob-
tusely angular, inferior antennae long ; beak
blunt, very sliglitly curved downwards;
shell striated withlongitucUnal ribs directed
obliquely do^\niwards and forwards ; colour-
less. 2 species : —

A. harpce (PI. 19. fig. 1) ; each branch
of inferior antenute with 3 long setae from
the extremity of the last joint only.

A. 7iani(s (PL 19. fig. 2), much smaller
than the last ; anterior branch of inferior
antemiEe with 4 setae, one arising from the
second, and three from the end of the last
joint.

This genus is scarcely di.stinct from Camp-
tocercus.

BiBL. Baird, Ami. N. Hist. xi. 91 ; and
Brit. Fniomos.129.

ACPtOSPEB'MUM, Tode.— A genus of
Sphaeronemei (Stylosporous Fungi), con-
sisting of minute, somewhat cartilaginous
perithecia, a few lines higli, discharging
long, wavy, erect, simple, microscopic .spores
from a terminal pore or ostiole. British
species : —

A. compressmn, Tode. On dry stalks of
herbaceous plants.

A. yraminitvi, Libert. On dead grasses.

A. cornntum, which is not uncommon
on the gills of blackened Agarics, is merely
the winter resting-state of Ayaricus tube-

7'OSilS.

BiBL. Fm/l. Flora, v. pt. 2. p. 221 ;
Grev., Sc. Crypt. Flora, t. 182.

ACROSPO'RIUM, Xees.— A generic
name formerly applied to certain species of
Oidiiim (see Oidiu.ai).

ACROSTALAG'-
MUS, Corda. — A genus
of Mucorini (Phycomy-
cetous Fungi), distin-
guished by its whorled
branched septate
threads, each branch
terminated by a globose
vesicle, which is pierced
by the tip of thebranch-
let, from which nume-
rous spores are given ott'
within the vesicle.

J^erticilliumlati'ritiHin
is a form of this beauti-
i'ul mould, with minute
naked spores.

The aceompannn?
fisrure represents Aero- Aci-ost.^lagnmscinnaba-

• , 1 . , . nil us (hichly magni-

Htalayinus cinnabannus, fled).

ACROSTICIIE.E.

[ 13 ]

ACTINOOOCCUS.

Corda. It arrows in large patches on rotten
potatoes. Iloirmanu regards it as a mere
form of Trir/idflicciinn roseum, which is
rather a Dacfi/liian.

BiBL. lierkeley, Cn/pfor/. Bvf. p. 294;
see also Trichothecium and Verticil-

LIUM.

ACROSTICH'E.T^..— A family of Poly-
podiaceous Ferns, with naked sori.

Illustrative Genera.

Acrostkhum. Sori seated on all the veins,
venules, and parenchyma, sometimes on
both surfaces; veins very much branched,
and anastomosing in more or less regidar
meshes.

Flati/ceriitm. Sori forming large patches
on the lower surface of the fertile fronds,
which are dichotomously forked with stag's-
horu-like divisions.

ACROS'TICI-IUM, L.— A genus of Acro-
sticheae(Polypodiaceous Ferns), ^^^th naked
sori seated on all parts of the leaf. Species
very numerous, mostly tropical. See
Hairs.

ACTINIA. — A genus of Coelenterata
(Zoophytes) ; class Actinozoa.

C/iar. Body conical or cylindrical, ad-
hering by a broad discoidal base ; mouth
simple, superior, surrounded by one or more
uninterrupted series of conical, undivided,
tubular retractile tentacula; marine.

The species are commonly known as sea-
anemones, and are found on the sea-coast
adhering to rocks and stones. A. mesem-
hryayithemum (I-I5" diam.), with numerous
azure-blue tubercles surrounding the mar-
gin of its oral disk, is very common on the
British coast.

The body is formed of a thick coat, the
inner layer'of which consists of longitudinal
and transverse unstriated muscular fibres.
The tentacles are covered with stinging
threads and capsules, as in the Acalephse,
often forming beautiful objects; and at
their bases are often foimd chromato-
phores. The space between the stomach
and the skin is divided into cellular
spaces by radiate partitions or mesen-
teries, the ovaries and the spermatic convo-
luted tubes being attached to these parti-
tions.

The connective tissue of the body is com-
posed of numerous fibres, cells, and inter-
mediate stages, of extreme delicacy (PL 41.
fig. 1). Dispersed throughout it are nume-
rous spindle-shaped, flexible, organic spi-
cula (PI. 41. figs. 1 a and 2), many of them

curiously marked by interrupted transverse
markings (lig. 2).

In r(^productive power they almost equal
thellydrtT; when cut across, new tentacles
form in a few weeks on the lower half, and
each piece becomes a new animal. They are
usually propagated by ova ; the embryos
being ciliated. INIany of the species exhibit
the most splendid iridescent colours.

BiBL. Johnston, Brit. Zooph.\ Tugwell,
Common Enfjlish Sea-Atiem. ; Gosse, Acti-
nol. Britnnn. 18G0, Mar. 7moI. 1, and " Be-
vonshire Coast ;" Bronn, Die Klass. 8fc. d.
Thierreichs ; Gegenbaur, Vergl. Anat. 1878 ;
Nicholson, Z(>o/. p. 178; Strieker, ifMjnfm
.y Comp. Uistol.

ACTINIS'CUS, Ehrenberg.— A doubtfid
genus of Diatomacefe,provided with siliceous
shells bearing radiating spines. (Cohort
Actinisceee.)

C/iar. Individuals microscopic, solid, ra-
diate, resembhng a star ; marine.

These organisms, which are found both
recent and fossil, are especially remarkable
for their valves being frequently found per-
forated. Species : —

A. Tetrasterias, Ehr. (PI. 18. fig. 1).
Stellate, with 4 free rays; diam. 1-1000".
Virginia. — A. Pentasterias, Ehr. (PI. 18.
fig. 2). Rays 5 ; diam. 1-1200". Recent on
the shores of Norway ; fossil in the chalk-
marl of Greece. — A. quinarius, Ehr. (PI.
18. fig. 3). Stellate, ravs 5, free; diam.
1-3000". ^gina.— ^. Sirius, Ehr. (PI. 50.
fig. 45). Rays 6, acute, winged at the
base; diam. 1-1200". Shore of Norway,
recent.—^. Discus, Ehr. (PL 18. fig. 4).
Disk-shaped, centre smooth, 8 marginal
ravs not exserted; diam. 1-1200". Gran.
— ^. Eota, Ehr. (PL 18. fig. 5). Disk-
shaped, centre smooth, 10 marginal rays
exserted; diam. 1-1900". Gran. — A.Lan-
ceorius, Ehr. Stellate, with 8 marginal lan-
ceolate rays, and some central rays which are
shorter on one side; diam. 1-240". Ant-
arctic Ocean.

BiBL. Ehrenberg, Leb. Kreidethierchen,
1840, p. m-,' Monatsher. 1844, p. 76, &c. ;
Klitzing, Bacillarien, 1844, p. 139; Spec.
Algarum, 1848, p. 141.

ACTINOB'OLUS, Stein.— A genus of
Infusoria.

BiBL. Kent, Infus. 1880, p. 214.
ACTINGCLA'DIUM, Ehr.— A genus of
Mucedines (Hyphomycetous Fimgi). No
British species vet recorded.

ACTINOCOC'CUS, Kiitzing.— A genus
of exotic Algse (marine), referred to Ri-

ACTINOCYATIIUS.

[ 14 ]

ACTINOPHRYS.

rularin hy Sulir (Kiitz. Tah, rhyc. 31,
fig. 2).

ACTINOCY'ATHUS, Keut.— A genus
of Infusoria.

BiBL. Kent, Man. Inf.

ACTINOCYC'LUS.— A genus of Dia-
tomaceee (Coliort Cosciuodiscese).

Char. Frustules solitary, fi'ee or adherent
to other hodies ; disk-shaped ; valves circu-
lar, exhibiting cellular markings, with ravs
or bands radiating from the centre, which
is free from the cellular appearance; no
internal septa ; marine.

The cellular appearance arises from the
existence of depressions upon the surface.
The radiant bands arise from undulations
of the surface, which are best seen in the
front view (PL 2o. fig. 17 b).

A. undulatus (PI. 25. fig. 17 a) ; ravs G,
diam. l-2.-i0 to 1-1100".

Kiitzing enumerates 34 species; some are
found fossil.

Smith admits A. duocknanns (rays 12),
A. sedenarius (rays 16), and A. ocfodenftrius
(rays 18) as British — species referred by
Elirenberg and Kutzing to the genus Adi-
noptychus. These are found in the Medway.

BiBL. Ehrenberg, Leh. Kriedethienhen,
1840, p. o7 ; Monatsber. 1844, and Mikroy. ;
Kutzing, Bacillar. 1844 ; Sp. Alyarnm^
1849 ; Roper, 3Iic. Jn. ii. ; Smith. Brit.
Diat. i. 25, and ii. ^'o ; Rabenhurst, Fl. Aly.
35.

ACTINODIS'CUS, Grev.— A genus of
Diatomacete.

Cliar. Frustules free, disk-shaped ; valves
granular, with a central nucleus, and nu-
merous (15) linear smooth rays extending
from it to the margin.

A. Barhadensis (PI. 36. fig. 22). Diam.
1-250". In the Barbadoes deposit.

BiEL. Greville, Mhr. Trans. 1803, 69.

ACTINOGO'Nimi, Ehr.— A genus of
DiatomacefB.

Char. Prismatic, frustules not forming
a filament, subspherical, with 7 or more
angles.

A. septenarium (PI. 18. fig. 8). With 7
angles. Found fossil in Barbadoes earth,
with Polvcvstina.

BiBL. 'Ehr. ILmatshcr. d. Bnrl. Ak. 1847 ;
Ann. N. Hist. vol. xx. p. 127.

ACTINOM'ONAS, Kent.— A genus of
Infusoria, Ord. Flagellata (Radio-flagellata,
Kt.).

Char. Resembles a stalked Actinophrys
with a long anterior flagellum ; neither test
nor central capsule.

2 species: — A. mirahilis (PI. 53. fig. 1);
diam. 1-2000". A.pusilla; diam. 1-3250".

BiBL. Kent, Infus. p. 227.

ACTINOPHRYl'NA, l)uj.— A family
of Radiolarian Rhizopoda.

Char. Body usually rounded, contained
in a shell or shell-less, giving off radiate
non-ngglutinating pseudopodia, either fiom
the entire surface, or from parts only ; spi-
cules and spines absent.

The genera may be divided thus : —

Shell absent.

Pseudopodia arising from all parts of

the surface Actinophrys.

(^Aoanihocysiis.)
Pseudopodia arising from a zone near

the circumference Trichodiscus.

Pseudopodia arising from one side IHugiopkrys.

Shell present.
Free.

Incrusted with foreign matter Plciirophrys.

Not incrusted, oblong.

Orifice lateral Trinema.

Orifice terminal y.urjhjpha.

Attached to foreign bodies JJrnuLa.

BiBL. That of the genera.

AOTI'NOPHRYS, Ehr.— A genus of
Actinophryina.

The species of Actinophrys are found in
both fresh and salt water. The body ex-
hibits contractile vesicles, mostly near the
margin, but sometimes more ditfused and
giving it a cellular appearance. Conjugation
has been repeatedly observed ; but authors
are not agreed upon its import. The move-
ment of the pseudopodia is veiy .slow : gra-
nules may be seen, contiiuially moving in
them, as in the Gromida and Foraminifera ;
but the circulation is much slower, and
requires great attention and a high power
to render it visible.

A. sol, E. (PI. 30. fig. 7i). Spherical,
colourless, whitish tentacles radiating from
all parts of the body; 1 or 2 contractile
vesicles strongly prujectiug on the surface;
parenchvma not reticiJar; diam. 1-430 to
1-1200"; fresh water.

A. Eichornii, E. (PI. 30. fig. 7 a). As
A. sol, but parencliyma presenting a more

appearance; diam.

or less regular celhdar

D. As A. sol, but marine.

1-100'

A. marina.^
rather smaller, and movements of tentacles
more rapid.

A. hreririrrhis, P. Greenish, not reti-
cular ; pseudopodia very short and very
numerous.

A. pcnnipes, CI. & L. Not reticular;
pseudopodia few, slender, and very long;
no projecting vesicle.

A. viridis,'E, (PI. 30. fig. 6). Spherical ;

t

ACTINOPTYCIIUS.

[ 15 ]

ACTINURUS.

greenish ; rays shorter than the body ;
diam. 1-280"' to 1-620"; fr. wator. Per-
haps A. sol coloured by chlorophyll.

A. ch'i/ifafa, D. Colourless, depressed,
teulaclos llexible, thickened at base, and
when contracted forming tinger-hke pro-
longations; diam. 1-770"; fr. water.

A. gramda, 1). Spherical; opaque in
centre ; rays taper, shorter than body ;
fr. water.

A. jmradoxa, Carter (PI. 51. fig. 13).
"With numerous capitate and longer simple
tentacles ; fr. water, Bombay.

A. ocidata, St. = A. sol? A. discus, D.=
TricJiodiscus sol, E. (PL 32. fig. 8). A. pe-
dkeUaia, D=rodoj)/tn/a /i.ra, E. A. stella,
PertY = the eggs of one of the Eotatoria.

The manner in which these animals feed
is cui'ious. Any part of the surface of the
body may be converted into a temporary
stomach. When an infusorium or a minute
alga comes into contact with one of the
tentacles, it generally becomes adherent.
The tentacle with the prey then slowly
shortens, and the surrounding tentacles ap-
ply themselves upon it, bending their points
around the captive, so that it gradually be-
comes enclosed on all sides. In this way
the prey is gradually brought to the surface
of the hoA.y, The spot at the surface of the
body upon which the captured organism is
lying slowly retracts, and forms at first a
shallow depression, which gradually becomes
deeper and deeper, in which the organism is
finally lodged. As the depression becomes
still deeper, its edges coalesce, and thus a
cavity closed on all sides is formed, in which
it remains for a certain time and becomes
digested. If there be any indigestible resi-
due, a passage for its exit is formed^ and it
is expelled by further contractions of the
substance of the body, and in the same or a
difterent direction from that at which it
entered, the canal and the aperture entirely
disappearing.

BiBL. KoUiker, Zeiischr. f. 2visse7is. Zool.
Bd. i. {Qt. MiiT. Jn. i.) ; ^tein, ArcJnv f.
Katunjesch. 1849 ; Brightwell, Infus. of
Norfolk ; Pritchard, Infus. ; Carter, Ann.
K. Hist. 1864 ; Claparede and Lachmann,
Etudes ; Tevty, Z. Ae?i77tniss ^x: p. 150.

ACTIXOPTYCHUS; Ehr.— A genus of
Diatomacese. (Cohort Coscinodiscepe.)

C/iar. Frustulessolitary, free, disk-shaped,
with rays and internal radiating septa;
valves apparently cellular (areolar), except
opposite the rays.

The presence of true internal septa is

doubtful; hence it becomes a question
wlujther this genus should not be consoli-
dated with ActinoLijclus.

Kiitzlng enumerates 16 species, distin-
guished principally by the number of septa
and rays ; A. ternarius, septa 3 ; A. quater-
narius, septa 4; A. senai-ius, rays 6 (PI. 2o.
fig. K')), &c. A. hexupterus, with 6 thick,
solid conical rays, is one of the calcareous
corpuscles of an echinoderm ; the margin of
the disk thick, undulate, and toothed within.
Many of the species are fossil.

BiBL. Ehrenberg, Infus. Ahh. d. Berl.
AJcad. 1838, and Berl. iferickt. 1844 ; Kiitz-
ing, Bacill. 134; Sp. AJg. 130; Greville,
Micr. Trans. 1866, p. 5 ; llabenhorst, Ah/.

' ACTINOSPH^'RA, Perty.— A doubt-
ful genus of Khizopoda.

Char. Body minute, spherical, suri'ounded
with ii'regular, rather rigid processes. Mov e-
ment that of swimming on various axes.

Processes stout and taper. Body colour-
less, containing greyish-green (food-) spots.

BiBL. Perty, Zur Kenntniss ^V. p. 189.

ACTINOSPH^'IIIUM = Acti'nophrtjs,
in part.

ACTIXOTHYRTUM, Kuuze.— A genus
of Sphperonemei (Stylosporous Fungi),
formino- minute round, Y\cr A

flat, blackspots, with a ..r-""- ; .; ,;.-v,

central boss of close, .-iji- -..• V ' '"'^fe"
radiating,fibrousstruc- 4^^^ : - '

tuie. British species: — ^?r ;F -

A. gramiyiis, Kunze. "5;^, . ■ '
On leaves and stalks of '''^-^■''?/-''; r. -- >• "

Grasses in spring (fig. Actinotliyriiungraminis

4). The innate, radi- (ingi'ly magnilied).
ately fibrous, shield-like perithecium finally
dissolves at the apex. The stylospores,
which are spindle-shaped, are formed be-
neath the disk, attached by their bases;
Fries conjectures that they are transformed
asci

It is probably a state of some Sphceria or
allied genus.

BiBL. Greville, Crypt. Flora, t. 218.

ACTIXOT'PJCIIA, Kent.— A genus of
Infusoria, fam. Oxytrichina.

ACTINU'RUS.— A genus of Eotatoria,
of the family Philodinasa, Ehr.

Char. Eye-spots-two, frontal (red) ; tail-
like foot with 2 lateral horny processes and
3 terminal toes. {^Rotifer with 5 points to
the foot.)

Agrees with Rotifer in general structure ;
teeth 2 in each jaw (PI. 43. fig. 2).

1 species, A. Neptunius (PL 43. fig. 1).

ADELOSIXA.

[ IG ]

ADULTERATIONS.

Colourless, body attenuated ; length 1-18"
to 1-86". Very common, aquatic.

ADELO_SI'NA,D'Orb.—Attirst regarded
as a generic form, but now recognized as
only the young condition of some of the
Milioline Imperforate Foraminifera. 8pi-
roloculina, Quinqneloculina, and Triloculina,
subgenera of Miliola, commence their
growth, after the fashion of their conge-
ners also, ■with a relatively large, subglo-
bose " primordial chamber ;" and the suc-
ceeding growth produces a curved flask-
like chamber, closely enwrapping one side
of the former. Until the successive lateral
overlappings by new chambi'rs buikl up the*
nearly o\-al outline of the adult Miliola, the
young shell is one-sided, and may be termed
" Adelosina." Found in aU seas, and com-
mon among Tertiary and Cretaceous fossils
at many places.

BiBL. Carpenter, Introcl. Foram. 75 ;
D'C)rbigny, For. foss. Vienne, 301.

ADE'XOID or Retiform Tissue.— A va-
riety of connective tissue, consisting of very
fine hbres, forming a network, in the meshes
of which are found numerous lymph-cor-
puscles. It forms the stroma of the spleen,
the lymphatic glands, &c. The fibres are
formed by the union of the processes of the
original connective-tissue cells. See Glakds
of Animals, and Lymphatics.

ADENO'MATA. These are tumours com-
posed of new formations of glandular tissue.
They occur in the mamma, mucous mem-
branes, the sebaceous and pineal glands, the

ovaria, and the liver.

BiBL. Green, Pathol. : Riudfleisch, Path.
1878.

ADENOPLEU'RA,Macalister.— Agenus
ofAcarina, fam. Ixodida?.

A. compressu7n. Found between the
scales of the West- African Pangolin {Manis
multiscutafa). L. 1-16".

BiBL. Macalister, Qti. 3Iic. Jn. 1872, xii.
p. 287 (figs.) ; Murray, Econ. Entom. p. 200

(%■)•

ADIANTUM,Linn.— AgenusofPteridec-B
(Polypodiaceous I-'''erns), with one elegant
indigenous (fig. 5), and many exotic species.
ADULTERATIONS (PI. 2).— A veij
important use to which the microscope is
applicable, consists in the detection of vari-
ous adulterations of articles of food, drugs,
and products of the arts and manufactures.
_ Tlie first point in a question of adultera-
tion is, to determine, by microscopic and
micro-chemical analysis, the structure and
composition of the pure substance ; and if

the Table given at the end of the Introduc-
tion be kept in view in this proceeding, but
few points will probably be overlooked. On
then comparing these results with those
obtained by a similar mode of proceeding in
regard to a suspected substance, there will
in general be found little difficulty in deter-
it is pure or not. If im-

mining whether

Fig. 5.

Adiantum Capillus Veneris (pinnule with
sori covered by indusia) ; 5 diam.

purities or adulterating ingredients are pre-
sent, the next point ^a ill' be to determine
their nature. To do this with certainty,
would require that the structure and com-
position of every kind of substance, either
natural or artificial, should be known, which
would imply an amount of knowledge pos-
sessed by no one. But the question is sim-
plified in practice, because substances used
in adulteration must be cheap, and either
grown or manufactured in quantities at
home, or imported from abroad. Hence
they are generally common, and it is pretty
well known of what they will probably con-
sist. In Plate 2 will be found the true
structure of the adulterated articles and
that of the adulterants. When the adul-
teration consists of a chemical substance as
it might be called, i. e. a salt, metallic oxide,
proximate principal, &c., its nature is readily'
determined by chemical analysis; but when
it consists of a vegetable tissue, which has
been perhaps subject to a partly chemical
process of mainifacture, the judgment must
be based upon the form of the a arious parts,
their size, relative position, and other par-
ticulars holding a place in the Table already
alluded to.

ADULTERATIONS.

[ 17 ]

^CTDIUM.

The following list of adulterations of
articles of jreneral consumption will serve as
a o-iiide to the inquirer, and as an index to
the special articles in this work in which
furtlier details will be found.

Arrow-koot (PI. 4G. fig. 20).— Cheaper

kinds of starch.
Bread. — Mashed potatoes, bean-flour,

rice, alum.
Cayenne Pepper. — Ground rice, mus-
tard-husks, deal sawdust, formerly
mineral coloiu'ing-matter of lead, &:c.
Chicory. — Roasted flours of corn and
beans, acorns, mangold-wurzel, parsnips,
carrots, mahogany-sawdust, burnt
sugar, red ochre, &c.
Cinnamon. — Flour of grain and potato,

cheap starches, &c.
Cocoa and Chocolate (fig.4). — Arrow-
root and other starches, flours, sugar,
chicory, red ochre, &c.
Coffee (fig. 5). — Chicory and its adul-
terations, as above, locust-beans, date-
stones, and figs.
Curry powder. — Flom-, ground rice,

red lead, red ochre.
Flour (PI. 4(3). — Meal of other grains,

beans, potato-starch, rice.
Ginger. — Flours of various kinds, mus-
tard-husks, cayenne pepper, turmeric.
Isinglass. — Gelatine from bones.
Lard. — Potato-flour.
INIusTARD (fig. 11 ). — Flour, turmeric.
Oat-meal. — Barley-meal.
Pepper and other spices (fig. 12). —
Flours of grain, peas, potatoes, &c.,
ground mustard, linseed, rice-husks, &c.
Pickles. — Dilute sulphm-ic acid (vitriol)

instead of vinegar.
Sugar. — Potato-flour, starches.
Tea (fig. 1). — Various leaves (sloe, elder),
catechu, mineral colouring-matters,
iron-filings, rice-husks.
Tobacco (fig. 16). — Various leaves (dock,

rhubarb, coltsfoot), paper, &c.
BiBL. Ure, Diet, of Arts and ManufartHres ;
Mitchell, Adult, of Food; Normandy, Iland-b.
Comntercial A}iahjsis; Schacht, Pruf. d.
im Handel vorh. Gnvehe, 1853 ; Wiesner,
Mikroshq)., i<fc.\ Angus Smith, Itt'p. of Man-
chester iSanit. Assoc. 18G3 ; Hassall, Food,
Sf-c; Parliam. Rep. on the Adidt. of Food,
^•c, 18-55 ; and Adult, detected, 1857 ; Od-
ling, Jonrn. Soc. Arts, 1858, vi. 318; Gar-
nierand llareU, Fahijicat. d. Siibst. Aliment. ;
Pereira, Mat. Med. ; Sorby on Spectroscope,
in Qu. Mic. Jn. 1800, p. 358 ; Klencke,
Verfulsch. t^'-c. (illustr.), 1879; Soubeirau,

Diet. d. falsif. Sfc, 1874 ; Blyth, Anal, of
Food. Sfc.

^'CIDTUM, Persoon.— a genus of Ure-
dinei (Coniomycetous Fungi), consisting of
parasitic fungi infesting leaves and herba-
ceous stems, appearing in their full-grown
condition as little cups filled with a reddish
or brownish powder (spores), formed by a
raising-up and bursting of the epidermis by
the parasite developed within. Many may
be detected in earlier stages by the deformi-
ties they produce in the growing structure
of the plants infested, or by pale or reddish
spots on the green surface, arising from the
presence of the imperfect fungus under-
neath. These plants are commonly known
under the name of blight, brand, ifcc. Their
history has recently received much eluci-
dation at the hands of Tulasne, De Bary,
and others ; and they are found to exhibit a
more complicated organization than was
formerly imagined. The organs of fructi-
fication are pi'oduced in two forms, bearing
gi-eat resemblance to the conditions lately
ascertained to exist generally in the Li-
chens. A brief account of the natural
history of certain of the species, derived
from De Bary and Tulasne, Avill give a
general idea of the character of this genus.

The nascent JEcidia are observed as mi-
nute spots upon the herbaceous parts of the
plants which they infest. When sections are
made of these and placed under the micro-
scope, it is fouud that the parenchyma of
the plant is deformed, irregular, and inter-
rupted by large intercellular passages,among
which ramify the filaments of the mycelium
of the fungus ; these are delicate, much-
branched and septate, about 1-3G00 of an
inch in diameter. At certain points these
filaments are crowded and interwoven into
hollow globular conceptacles, about 1-180
of an inch in diameter, immediately beneath
the epidermis, the interior of which concep-
tacle is lined with delicate filaments (about
1-12000 of an inch in diameter) arising at
all parts and converging towards the centre,
except at the upper part, (Avhich is open,
and only shut from the external air by the
persistent epidermis of the nurse-plant,)
where they are directed upwards. A gra-
nular mass occupies the centre of the con-
ceptacle, separating the converging fila-
ments from each other. By the growth of
the upper filaments and the increase of the
central granular mass, the whole structure
increases in size, so as to pusli the epider-
mis up above the surrmmdiug surface, finally

C

iKCIDIUM.

[ 18 ]

JECIDIUM.

bursting it, when tlie upper filaments (^^a-
7yi/}Iii/-fe-i) grow out tlirongb the oritice and
form a little funnel- shaped tuft on the sum-
mit of the protuberance, through the middle
of which the granular mass formed below
makes its escape. These bodies may be
found commonly on the spurges (yE. Eu-
pliorhirp)^ the barberry {JE. Berberidk), net-
tles {^. Urticce), Composite (^. Composi-
tarum), &c., early in the season ; later they
may frequently be recognized in a dried-np
condition, being forerunners of the true spo-
riferous bodies (PI. 26. tig. 1). The name
applied to these organs is spermogonia. The
filaments converging into the centre of these,
termed sterigmafa (PI. 20. figs. 2, 3, s t), are
the important parts of the structure ; they
terminate in rows of minute bodies of oval
form, about 1-6000 of an inch long and
1-12000 in diameter (ibid. 8 p), which be-
come detached and separated, falling loose
into the cavity, where, by a continued
growth and shedding of similar bodies from
the converging filaments, they accumulate to
form the granular mass above spoken of as
existing in that situation. The nimiber
ultimately becomes enormous, and a gela-
tinous substance is secreted, glueing them
into a mass. "When placed in water under
the microscope, or when wetted by rain in
its natural jJosition, the ripe mass swells and
is protruded through the orifice of the sper-
mogonium on the svu'face of the leaf. By a
longer action of moisture the jelly dissolves,
and the minute bodies (spermatia) spread
about in the water, exhibiting "an oscilla-
tory motion, as of a body attached at one
extremity." De Eary states that he found
iodine arrest this motion, while it persisted
for some time in solution of chloride of cal-
cium. No cilia can be detected. Fresh
spermatia were coloured brifiht purple red
by sugar and sulphuric acid, but at the same
time were so acted on that it could not be
made out whether they possessed a mem-
brane free from nitrogenous matter. Solu-
tion of potash renders invisible the outlines,
not only of the spermatia, but of the sterig-
mata and paraphyses. The resemblance of
these bodies to the spermatia of the Lichens
(see Lichens), is too eAident to be mis-
taken ; hence the same terms are applied to
the corresponding organs.

The spermogonia occur either in regular
groups, or scattered just like the periflucia ;
when the latter are on the same surlace of
a leaf, they often form a circle round the
former. Frequently they burst through on

opposite sides of a leaf; and then the sper-
mogonia are oftenest on the upper, the perir-
thecia on the lower face (PI. 26. fig. 1 sp).

After a number of spermogonia have been
successively developed and discharged their
spertnatia, the mi/celiutn, from which they
originated, produces a new globular body
formed of densely interwoven iilaments,
usually in the interior of the substance of
the leaf or stem, not immediate^ beneath
the epidermis, and ordinarily colourless.
Increasing in size in all dirt'ctious, this glo-
bular body, the perit/ieciion, soon presents
at its base, i. e. the point furthest from the
nearest epidermal surface, another body
composed of very numerous free-ending
filaments enclosed in a cellular membrane,
which body rapidly gi'ows up within the
peiithecium, in the direction of the surface
of the leaf or stem. The filaments, at first
very delicate, are crowded very close to-
gether ; and each exhibits in its interior a
row of short, colourless, roundish cellules,
the uppermost of which is always the largest
and the most advanced in development.
These cellules are the sjjores, and the fila-
ments in which they are found are the spo-
rangia or thecce.. The membrane enclosing
the sporangia, the peridiiini of Persoon,
grows pari passu with them, and is com-
posed likewise of rows of cells, which stand
in a circle around the sporanges, but are
firmly connected together side by side by
an intercellular substance ; this membrane
closes in like a bell or vault over the spo-
ranges. By the reciprocal pressure of all
parts, the cells of this membrane, at first
spherical or ovate, become polygonal. At
a certain stage the apex of the perithecium
gives way, so that it forms a kind of cup
around the membrane enclosing the mass
of sporanges arising from the base. The
whole structure has by this time come im-
mediately up to the underside of the epi-
dermis, which is next ruptured, and the pe-
rithecium and the sporanges are protruded,
more or less, according to the habit of the
species (PI. 26. fig. lp,p). The upper por-
tions of the rows of cells composing the pe-
ridial membrane then separate more or less
from each other, splitting into lobes, so as
to set the sporanges free, and form a kind of
cup with toothed margins seated in the ex-
panded perithecium ( figs. 6 and G a) .

The spore>(, which are at first delicate
cellules, subsequently ac(juire a tough mem-
brane, increasing considerably in size, so as
to distend the parent utricle or sporauge,

tECIDIUM.

[ 19 ]

AElilAL ROOTS.

■wliicli is ultimately only recognizable where
it coimeets the spores together iu a monili-
foriu series. Tiie spores iu most cases now
acquire a deeper colour (except in ^. leuco-

^cidium Compositarum, Mart.
Fio-. 6.

Peridia in various stages of growth on the surface of ;
leaf: 30 diam.

Fig. 6 a.

Perpendicular section through a hurst peridium, show-
ing the sporanges contained in it : 100 diam.

coniuni), owing to contents chieiiy accu-
mulated in the centre. Their membrane
is colom-less, their form finally irregularly
polygonal ; and the diameter varies much,
even in ripe spores of one and the same
species, from 1-1000 to 1-1800 of an inch.
The upper spores are often ripe at an epoch
when young spores are .-till in course of pro-
duction at the lower end of the sporanges ;
finally, however, the development ceases be-
low, and the tube elongates a little beneath
the lowest spore, forming a kind of pedicle
or basicUum to the row. The ripe spores
either soon fall apart and fill the cup as a
loose powder, along with short incomplete
sporanges, or the rows persist even after
they are mature, held together probably by
a firmer peridial membrane.

The British species of ^Ecidium are nu-
merous; more than thirty are described by
Berkeley in the Jiritish Flora, many df
which are common, especially those of the
Mints, the Compositte (such as the Colts-
foot, &.C.), the Barberr}', the Cloosebeny,
Buckthorn, Spurge, Nettle, &c. (^Z?. Coin-
pusitarum, Mcutlice, Berheridis, Grossularice,
crasstcm, Euphorbice, Urticce, 4'C-)-

Oersted and De Bary have made expe-
riments which seem to prove that jEcidiKin
Berberidis is a development of Puccinia
(//•ainims ; a full account of which will
be found in Cooke and Berkeley, Futiyi,
p. ISO.

BiBL. For Species : — Brit. Flora, ii. pt. 2.
p. 309 ; Greville, Sc. Crypt. Flora, pis. 7,
02, 97, 180, 209 ; Reess, Disp. Ured. 1S79.

For Auat. and Physiol. : — Uuger, Exan-
theme, pp. 297, 300,' t. 3. f. 18, 19, t. 4;
Meyen, PJlanzenpath. pp. 143, 148-50 ;
Tulasne, Vompt. limdus, March 24 and 31,
1851 ; Ann. d. Sc. A'af. ser. 3. t. xv. ; ibid.
ser. 3. t. vii. p. 45; ser. 4. t. ii. pp. 126, 173;
Leveille, Sur le dev. des Uredinees, A7in.
des Sc. Nat. ser. 2. t. xi. ; Corda, Icon. Funy.
iii. t. 3. f. 45 ; De Bar}', Brandpilze, J3erliu,
1853, p. 55 et seq. pis. 5, G, and 7 ; Sachs,
BotaniJi, 1874, p. 332 ; Heufrev, Bot. (Mas-
ters), 1878, p. 460.

^GERITA, Persoon.— A genus of Stil-
bacei (Plyphomycetous Fungi) characteiized
by short necklace-like threads consisting of
irregular spores produced from flexuous,
branched, radiatiug- sporophores, forming a
subglobose mass. yE. Candida, Persoon,
grows on damp twigs iu marshy places,
consisting of scattered white grains about
the size of a poppy-seed. ^E. setosa, Grev.,
belongs to the genus Volutelhi.

BiBL. Greviile, Crypt. Fl pi. 268. fig. 1 ;
Ann. N. H. 1859, iii. 362, jjl. ix. f. 7.

^FIGYRIA. — A genus of Infusoria=^r-
vilia, Duj. JE. leyumen=Erv. leyumen, D.
Three other species.

BiBL. Claparede and Lachmann, Infus.
&-C. i. p. 288.

ANGSTR(E'MIA, Br. and Sch.— A ge-
nus of LeptotrichaceoLis Mosses, including
many Dicrana, and Ccrutodon cylindricus,
Br. and Sch.

BiBL. Miiller, Sipiops. Muse. i. p. 426 ;
Wilson, Bryoloy. Brit. pp. 72, 85.

AERIAL ROOTS.— A very large pro-
portion of the exotic Orchids are epiphytic
plants and produce aerial roots, which ab-
sorb moisture from the atmosphere; the
same structure occurs in many tropical

c'2 .

^TEA.

[ 20 ]

AGATE.

Araceas. The surface of these aerial roots
is clothed by a peculiar tissue, formed of
cells containing a delicate spiral fibre upon
the wall (PL 4S. fig. G). The strata of spiral-
fibrous cells are sometimes numerous, and
they cover up the true epidermis of the
root. The growing points of such roots are
green ; but the spiral-librous cells soon come
to contain nothing but air, and then assume
a silvery-white colour.

^TEA, Lamx. See Anguinaria,

^THA'LIU -M, Link. A genus of Myxo-
mycetes. The common ^^thalium^ AL. sep-
tictim, L. ijlavum, Grev.), occurs frequently
on tan in hot-house^, where it is very inju-
rious, from the rapidity of its growth and the
abundance of its spores. The ordinary form
is yellow; but violet and reddish-brown
varieties have been met with. It grows
also on mosses in woods. Other species of
JEihalmm have been found growing upon
iron, lead, or other mineral substances,
sometimes a few hours only after they have
been heated, so that the appearance seems
quite marvellous. The cream-like matter,
of which the part answering to the myce-
lium or allied production in other Fungi
consists, exhibits Amwha-\\k'? movements.

BiBL. GreviUe, Crypt, Flora, t. 272;
Sowerby's i^«?25^j, t. 399. fig. 1 (as liettcularia
hortensis, Bull.), figs. 3 & 4 (as R. carnosa
and H. cere(i) ; Bolton, Brit. Fungi, t. 134
(as Mucor sepfiats, L.) ; Berkeley, Cryjtt.
Bot. pp. 23G, 339.

AGARICIM.— A family of Basidiomy-
cetous Fungi, belonging to the tribe Ilyme-
nomycetes, comprising a great portion of
the more important esculent species, cha-
racterized by an inferior hymenium spread
over distinct gill-like processes, which are
often easily divisible into two plates. In a
few species the interstices of the gills are
traversed by veins so as to produce the sem-
blance of pores. Amongst the more obscure
species of the vast genus Ayaricus, the hy-
menium is at first superior, but finally be-
comes inferior by the turning over of the
pileus, which is attached at one point only,
or by a very short stem.

Tiie hymenium is composed of vertical
cells, called hasidia by L6veill^, sporophores
by Berkeley. These bodies are elliptical or
elongated cells growing out from the surface
of the lanielhe, with four slender stalk-like
processes at the upper end, each bearing a
single spore, which becomes detached when
ripe. These basidiospores are observed by
means of cross sections of the lamelUe ; the

sections must be very thin, and require a
high power for satisfiictory observation.
The sections keep tolerably well put up in
chloride of calcium or glj'cerine, and are
luost instructive when taken from a series
of specimens of ditFerent ages. See Aga-
Eicus, Basidiospores, and Hymenomy-
CETES. The bodies called cystidia or ^w//j-
fiaria, are globular or oval cells, found asso-
ciated'with the basidia, containing granular
matter exhibiting molecular motion Avhen
discharged. These organs have been sup-
posed to represent antheridia, but are more
probably paraphyses or abortive basidia.

BiBL. Berkeley on the Fructif. of llyme-
nomye. Fungi, Ann. N. Jlid.i.Sl ; Leveille,
Siir l^ Hymenium des Champignons, Ann. S'c,
Nat. 2 ser. viii. 321 ; Hoffman, Bot. Zeit.
xiv. p. 137 ; Cooke, Illustr. Brit. Fungi,
1881.

AGARICUS, Linn.— A genus of Agari-
cini (Hymenomycetous Fungi ; one of the
largest genera in the Vegetable Kingdom,
comprising not only a multitude of European
species, but many from tropical climates.
Ag. catnpestris is the common Mushroom.

See Hymenomycetes.

AGATE. — The term agate is specially
applied by geologists to the concretions
and geodes of chalcedony, formed in the
steam-holes and the fissures of volcanic
rocks. They consist of crystallized and
crystalline varieties of silica, coloured with
metallic oxides. Successive and concentric
layers of chalcedony, coating the insides of
the cavities, have formed solid or hollow
nodules, the innermost layers being often
colourless or amethystine quartz. In the
chalcedony no definite crystallization can be
seen, only an obscure fibrous structure at
right angles to the planes of deposit, which
latter are usually Imnpy or mammillary, and
often render the mass flaky. In some
specimens this fibrous structure becomes
more evident in successive layers — minute,
close-set, crystalline prisms being visible on
fracture ; and these may be succeeded by
regular quartz-crystals. Those paler vari-
eties of quartz, which consist of concentric
layers of radiately grouped cr^'stalline
needles, frequently polarize light very
beautifully. From the unequal resistance
of some of the layers to hydrochloric acid,
cut agates may be prepared' to take printer's
ink and to give impressions on paper. The
relatively open prismatic structure of some
layers allows agates to be partially coloiu-ed
by the absorption and carbonization of oil

AGATE.

[ 21 ]

AGATTIISTEGIA,

or honey, or by chemical infiltrations.
Nearly all the agates (onyx, sardonyx, &c.)
of commerce are thus treated. Carnelian
and sard are either burnt or naturally oxi-
dized portions of agate. Sometimes agate
contains crystals of calcite imbedded in its
substance ; and whether coated over, or
replaced, these have sometimes given the
outlines in the fortification-agates, which
are common and elegant objects. Small
stalactites, or concentric knobs, of chalce-
dony enclosed and invested in the cavities,
when cut through, give rise to the pretty
eye-agates. Some chalcedonies contain
delicate branching filaments of delessite and
other minerals, and are known as moss-
agates and mocha-stones. Great micro-
scopic interest lies in the so-called moss-
agates of the south coast of England and
the Isle of Wight. These are altered
sponge-masses from the chalk and green-
sand ; and, with the chert and flints, have
been examined by Bowerbank, who sup-
posed them to have originated in the at-
traction and solidification, by sponges, of
silica dissolved in the water of the ancient
ocean. The spicula of sponges are com-
monly fovmd ; also very frequently the
fibres, sometimes in a perfect state of pre-
servation, but usually presenting the ap-
pearance of having sufiered to a great extent
from maceration and disruption of their
component parts previous to fossilization.
Generally the fibres adhere together in
confused masses, presenting a moss-like
appearance, with here and there one or two
in a better state of preservation ; and occa-
sionally, near the outer surface of the mass,
small portions of the tissue are found quite
perfect ; in other parts all the intermediate
states between perfect preservation and
nearly complete decomposition may be ob-
served. The siliceous matter in which these
remains are imbedded, usually presents a
clear and frequently a crystalline aspect,
while the remains of the organized mass
are strongly tinted with colours : bright
red, brown, and ochre-yellow prevail ; but
occasionally the colours are milk-white, or
bright green. Sometimes the interior of
the tubular fibre only is filled with ceilour-
ing-matter, whilst the sides are semipellucid
or of a milky white ; in others the whole of
the fibres are impregnated with it. PI. 25.
fig. 14 represents sections of a piece of moss-
agate (Indian), showing the silicified fibres
of sponge «rt, the gemmules h, a separate
fibre at c, and spicula at d. Bowerbunk

has also described an Alcyonitic structure
in a moss-agate.

The supposed vegetable structures in the
majority of such agates, described by Tur-
pin, Midler, and oihers, have been shown
by Goppert to be inorganic products,
chiefly dendritic deposits of oxide of iron.
His essay contains an elaborate history of
the strange notions which have at various
times been propoimded concerning these
objects. Gergens has imitated the coloured
confervoid appearances by decomposing
green vitriol with a weak solution of silicate
of soda.

Confervoid bodies, however, have been
recognized in the green moss-agate of In-
dia ; and a living Conferva was actually
found in colloid silica by Roberts and
Slack. Schaftiier has described green con-
fervoid tissue, referable to Vaucheria, Spiro-
gyra, &c., besides spores, in green Indian
stones ; and he traced the green colour of
the spots in a red opake jasper to Proto-
coccus.

There are two distinct points connected
with the presence of these supposed organic
remains in agate : one is, whether they
really are organic, and the other is whether
they are related to the formation of the
agate, or merelj^ accidentally present. The
first is a very dilficult point ; we have only
the microscopic appearance of the bodies
under one set of conditions to judge from :
this is always very unsatisfactory ; many of
the appearances most peculiar to organic
bodies, especially when the latter are not
connected so as to form a tissue, can be
closely imitated by crystallization. Still
the mass of evidence is decidedly in favour
of the appearances really representing por-
tions of sponges and Confervo3.

BiBL. Bowerbank, Trans. Geol. Soc. (2)
vi. 181 ; Ann. N. II. x. (1842), 9 and 84 ;
Quart. J. G. S. iv. 319 ; Goeppert, Batishon
Flora, 1848, p. 57 ; Brewster, rhil. Mag.
(.3) xxii. 213 ; Noggerath, Ilaidinger's Nat.
Abhandl. iii. 93, 147, and Neucs Jahrb. f.
Min. 1847, 473 ; Gergens, N. Jahrb. f. M.
1858,799; Schafiner, Flora, 1859, no. 36;
Bisehof, Lehrb. Chcm. Geol. iii. 630 ;
Fieusch, Poggendorf's ^«n. cxxii.94; Lange,
Halbedelsteine, ^-c'., 1808 ; Hamilton, Q. J.
Geol. Soc. iv. 209 ; Billing, Ihe Science of
Gems, 1867 ; Zirkel, Beschaffenh. Min. u.
Gest. 1873, 108 ; Rupert Jones, Proc. Geol.
Assoc, iv. 439 ; Rudler, Po/j. Sci. Rev. xvi.
1877, 23.

AGATIHSTE'GIA, D"Orb.— An order of

AGLAOniENIA.

[ 22 ]

AIR.

Fornminifera in D'Orbigny's classification
(l<S:?o). It may be said to comprise Cor-
7ni.spira, MUiola (subgenera Unihcidhia,
Bihmdina, Trilocvlina, Qiiingueloeuh'na, Spi-
rnlocn/hui, Cnicilocnlina), Ilaucrinn, and
Fahtdaria, members of the family 3Iiliolida,
as established by Car] enter. The peculiar
ball-of-thread-like folding of the segments,
"whence the name, is constant in the three
last-named genera ; but in CoruN.-^pira it is
merged in a discoidal spire at an early stage
of growth.

BiBL. D'Orbigny, Foratn. Cnha, p. 145 ;
Foram. Canaries, p. 140; Foram. Americ.
p. 68 ; For. Foss. Vienn. p. 255 ; AYilliam-
son, Brit. Foram. p. 78, &c. ; Carpenter,
Int. Foram. p. GG.

AGA'VE. See Fibeotjs Structuees.

AGLAOPHE'NIA, Lamx (Pfr.).— A
genus of Polypi, of the family Plumula-
riidse. It consists of I'limiularia crixfuta,
myriop]i;iIh(m, and pennatiila (Johnston).
See Plumulauia.

BiBL. Iliucks, Brit. Hydr. Zooph. p. 284,
pis. 63 & 64.

AGLAOS'PORA, De Notaris.— A genus
proposed for Sjiha-ria profvsa, on account of
the a'ici containing only 4 sporidia ; but
Tulasne has extended it to some species
with eight sporidia, on account of the rela-
tion of the pycnidia to the perithecia. The
brown spores of A. profiisa, which is not
uncommon on Rohinia pseudacacia, are
beautiful microscopic objects.

BiBL.. Tulasne. Sel. Fimf/. Carp. ii. p. 158.

AGO'NIUM, CErst.— A genus of Cou-
fervoid Alg;is, fam. Oscillatoriaceee.

Char. Filaments very slender, rigid,
flexuous, tufted, jointed ; a single sporidium
in each joint.

A. ctntrale (PI. 3. fig. 1). Marine ; 3-
5'" long; attached to stones.

BiBL. Rabenhorst, Alg. ii. 160.

AG'RION. — A genus of Nem-opterous
Insects. See LiBELLULiDiE.

AGY'RIUM, Fr.— A genus of Lichena-
ceous Lichens, tribe Graphidei.

1 sp., A. rafiim. Thalliis forming
whitish spots; apothecia bright red. On
old posts.

BiBL. Leighton, Lieh. FL, p. 392.

AINAC'TIS, Kiitzing.— A genus of Os-
cilltdoriaceous plants growing on stones in
alpine streams. The two known species
have been found in Britain.

A. alpina. Fronds from 1-12 to 1-2" in
diameti'r, often confluent, formed of re-
peatedly dichotouious filaments, dark olive

green, containing separate particles of car-
bonate of lime. Hassall, Brit. Fr. Alyce,
Ixv. 1. 4 ; Kutz. Tab. Fhi/c. vol. ii. pi. 63.
1 ; Zonotrichiu hcematites, Rabenhorst, Ala.
ii. 212.

A. calcarea, Kiitz. Fronds 1-4 to 1-2"
in diameter, orbicular, convex, idtimately
confluent, sometimes greenish, often dark
chestnut, composed of dichotomous fila-
ments,.at length incrusted continuously with
carbonate of lime. Kiitzing, I.e. jjI. 63. 2;
Z. calc. Rab. ; Lithonema calcaria, Hassall,
tab. Ixv. fio-. 2.

Kiitzing states that the gelatinous sheaths
of the filaments of yl. afpina have a spiral-
fibrous structure. See Spieai, Stetc-

TUEES.

AIR. — It need scarcely be remarked that
the air consists essentially of a mixture of
two gases, oxygen and nitrogen, in the pro-
portion by volume of about 21 parts of the
former to 79 of the latter, with variable
quantities of gaseous carbonic acid (about
l-2000th) and aqueous vapour. As the
component molecules of gases are invisible
with any powers of the microscope, the air
possesses no microscopic characters. In two
respects, however, the study of the air is of
great importance : — 1st, in regard to the op-
tical appearances produced by the passage of
light through it when contained in bodies
submitted to microscopic examination ; and
2ndly, in regard to the particles which are
always, in greater or less numbers, sus-
pended in it.

In microscopic investigations, we meet
with air either existing in cells or cavities
in various tissues, or in the form of bubbles,
confined by the liquid in which the objects
are usually immersed. "VVhen surrounded
and confined by liquid, it mostly assumes a
spherical form, in accordance with the law
of hydrostatics, that the pressure of fluids
is equal in all directions; sometimes the
spherical form is exchanged for that of a
compressed or oblong spheroid, the result of
the pressure of the glass slip covering the
object. When confined in cells or cavities,
it assumes the form of these. It is in ge-
neral easily recognized by transmitted light
from the smooth and even darkness or
shading given to its margins, whilst in the
centre it appears luminous and clear. Some-
times the dark margins of air-bubbles have
a pale purjjlish-yellow, blue or greenish
tinge. By reflected light, of course, no dark-
ness is produced, but it then appears vitre-
ous and shining, in co^isequence of the re-

AIR.

[ 23 ]

AIR.

flection taking place from its surface. So
long as air-bubbles or confined portions of
air are large, the optical appearances above
described are sufficiently characteristic ; al-
though should any doubt exist as to the
nature of a supposed accumulation of air,
the latter must be displaced, either by pres-
sure bet^veen two slips of glass, or by im-
mersing the object in which it exists in some
liquid and apphnng heat. When, however,
air is couiined within very minute cavities,
especially when these possess definite forms,
the clear centre is frequently no longer to
be detected, the whole appearing perfectly
black and solid; and serious errors have
arisen from inattention to this cii-cum-
stance, as explained in the Introduction
(p. xxxv).

The corpuscles of dried bone were thus
formerly considered sohd bodies, as their
name implies, and as consisting of calcare-
ous matter, until it was found that they
could be filled with a liquid. In all cases,
tlieu, where absolute certainty is required
of the nature of an apparent air-bubble or
accumulation of air, attempts should be
made to displace the mass, either by pres-
sm-e or prolonged immersion in a liquid,
especially with the aid of gentle heat.

The appearance presented by air con-
tained in tissues, is easily studied in a dry
section of any kind of pith or other vege-
table structure, such as elder-pith, rice-
paper, or cork ; cork is really heavier than
water, and owes its lightness to the air it
contains. On immersing these in water,
this liquid soon enters the lateral cells, but
long digestion is required before the in-
ternal cells become filled with it and the
whole of the air is displaced. Soaking in
alcohol before immersion in water greatly
facilitates the displacement of the air.

The determination of the actual nature,
as regards chemical composition, of air con-
fined in tissues, is a matter of difficulty
where the quantities are microscopic. The
nitrogen can only be detected by its nega-
tive properties to reagents. The presence of
oxygen might be determined by moistening
a section of any structure with recently
boiled distilled water and then placing it in
a cell containing a solution of protosulphate
of iron, or an alkaline pyrogallate, and im-
mediately sealing the cell with varnish and
allowing the action to continue for some
time.

For the detection of Caeboxic Acid, see
that article.

There is yet a source of fallacy in the
detection of air imprisoned in structures
where these are of a hard resisting nature,
as in mineral bodies. An illustration of this,
with the method of its avoidance, is given
under Topaz, and Rocks.

In regard to the solid particles present
in, or subsiding from the air, and forming
dust, these consist principally of the spores
of fungi, lichens, mosses, and algas, pollen,
the detritus of the soil, fine fragments of
vegetable and animal fabrics accidentally
separated and diffused during the ordinary
operations of every-day life, the dried but
not dead bodies of infusoria, crystals, and
metallic particles, and the ova of the lower
members of the animal kingdom. The kind
of bodies present in the air varies according
to the locality ; thus in cities, the dust con-
sists mostly of fragments of products of
manufactures, with the spores of fungi,
mixed Avith particles of carbon or soot, the
ova of the lower animal forms being com-
paratively few and belonging to a limited
number of species ; whilst in open places in
the country, a more ready diffusion of the
spores of plants and the ova of animals
takes place, and the sources from which
fragments of textile fabrics are derived are
less numerous.

The inorganic particles deposited from
the air, consist of fine grains of sand, wafted
from the soil by winds, and rarely fall other-
wise than near the currents by which they
are borne. They are easily recognized by
their angular forms, their resistance to com-
pression, and their not being destroyed or
decomposed by exposm'e to a red heat.
Certainty as to their composition can only
be obtained by chemical analysis. See
Sand.

The organic forms deposited from the air
formerly gave rise to much perplexity. It
has long been known that when solutions of
various organic substances, or liquids con-
taining these matters undergoing sponta-
neous decomposition, were exposed to the
air, the liquids were soon found to teem
with life — infusoria and fungi, according to
the nature of the decomposing matter,
being discovered in them in abundance. It
seemed very natura"l to conclude that these
derived their origin from the substances
undergoing decay ; and it is not to be won-
dered at, that the fact should have given
rise to the conclusion that here was evidence
of the spontaneous or equivocal generation
of animals.

AIR.

[ 24 ]

AIR.

This theory lias now ceased to he aclinow-
ledgecl : aud a common source of fallacious
reasoning lies in overlooking the fact, that
the air contains the germs of numerous or-
ganic forms, still capable of resuming their
active vitality when they meet with the
requisite conditions. Of this we have con-
vincing proof. For, if the liquid containing
the decomposing matters be heated to ebul-
lition for some time in a bottle or other
vessel, into the cork closing which two
bent tubes are inserted, and, after the air
has been completely displaced by the vapour,
the fresh air admitted be previously passed
through red-hot tubes, or Pasteur's filter of
cotton-wool, organisms cease to be met with,
and the decomposition of the substance and
growth of the organisms no longer take
place, even in an indefinite period. That
the liquid in these cases does not experience
alteration rendering it incapable of sup-
porting the life of the animal forms intro-
duced, is shown by subsequently admitting
ordinary air, when the organisms appear as
rapidly as in fresh liquids.

Vegetable forms are also constantly met
with as deposited from the air. In them,
the spores are probably alone the bodies by
means of which the diifusion of the lower
plants by the agency of the air is efit?cted.
Minute fungi are frequently found, like the
animalcules above alluded to, in various
vegetable and animal liquids undergoing
fermentation and decomposition. The ques-
tion of the relation of these fungi to the
processes will be found discussed under
Feemektation and I'i'teefaction ; and
the various genera and species found in dif-
ferent kinds of liquids are treated of mider
the heads of these liquids. Fungi and algae
are also met with as parasites and ento-
phytes upon and in living animals : for an
account of these, see Parasites.

The lower forms of fungi are frequently
found growing upon surfaces from which
they can derive no nourishment, as upon
slips of glass, window-panes, &c. In these
cases they must derive their nourishment
from the atmospliere. When found in these
situations, however, they soon cease to gxow
by subdivision of cells or gemmation, but
speedily form spores. The most common
ones in these situations are the sugar-fun-
gus— Penicillivin glaticum and Asjiergilhis
peniciUatus, Miicor, &c.

The method of distinguishing whether
any minute particle deposited from the
air is of animal or vegetable natme, is de-

scribed under Tissues, Animal and Ve-
getable.

Organic bodies derived from the air are
sometimes met with in snow and hail.
See S^'ow and Hail.

The air has frequently been examined in
regard to the presence of animal or vege-
table organisms, which might accoimt for
the production of epidemic and infectious
diseases ; but the results obtained in this
direction have not been very satisfactory.
Yet as, on adopting the principle of Pasteur's
filter, and the use of germicides in the
treatment of wounds, and in pm-ifying the
air when infectious diseases prevail, most
decided benefit has been shown to result,
the further examination of the air may allow
of the detection in it of the germs of
disease which have probably been too often
passed over as mere granules, globules, &:c.
of no import. The best plan of making
these experiments is to connect a glass tube,
twice bent at right angles, with an aspi-
rator : the free end of the tube should be
drawn to a tine point; aud just above this
the tube should be blown into a bidb. The
point is then immersed in a small quantity
of pure water, and the water allowed to
run very slowly from the aspirator. The
water is then slowly drawn into the tube,
and the air is washed as it passes by the
water in the bulb. When a large quantity
of air has been washed by the water, the
latter is shaken b'riskh- and allowed to run
into a clean glass for examination.

Another method consists in closing, by
fusion, the end of a glass funnel, filling
this Avith ice, and collecting the drops of
water condensed from the air on its ouside,
in a receptacle placed beneath. See Miceo-
zymes and Schizomycetes.

Pouchet and Maddox have devised other
forms of apparatus for this purpose.

The appearances presented by air as exist-
ing in cell-cavities is represented in PI. 47.
fig. 23 «, in the delicate cavities of a hair
in PI. 29. fig. 1 ; and the lower part of the
same figure represents a portion from which
the air has been displaced bv liquid.

BiBL. Pasteur, Ami. d. Chim. 18G2, p.64,
& Siir les corpuscles organises de Voir, Ann.
d. Sc. Not. (Zool.) 1801, xvi. p. 26; Magnin,
Impabtdisyne, ^-c, 187G; Robin, Micr. 1877,
p. ^70; Miquel, Comptcs Jx'cndus, 1,^79;
Cunningham, Mic. e.vcnn. of air, Ca/cidta ;
Tissandier, Poiissicres de rair ; Pouchet,
Aeroscopie, 1870 ; Tvndall, Led. Lond. Inst.
(Times, Dec. 12, 1877), k I'roc. Hoi/. Sue.

AIR-BLADDER.

[ 25 ]

ALARTA.

1878; Beauregard & Galippc, Guide S)C.
1880, p. 764 ; Robin, Micr. 1877, p. 870.
AIH-BLADDER of Fishes. See SwiM-

MIXG BLADriEB.

AIR-BUBBLES. See Air.

AIR-CELLS or Sacs of animals.— These
are dihTtations or expansions of the air-
passap'es.

In birds, these are membranous ca^ities
communicating with the lungs and dis-
tributed through the chest and abdomen.
They extend over almost all parts of the
body, around the joints of the extremities,
into the bones, the quills, and the feathers,
and even between the skin and subjacent
muscles. During inspiration, the air enters
all these cavities.

In insects, the air-cells or sacs consist of
dilatations of the trachepe. See Teacher.

Their obvious use is either to diminish
the specific gravity of the body, or to act as
reservoirs of air during the impeded respi-
ration connected with flight.

BiUL. Siebold and Stannius, Lehrh. cl.
veiy/l. Anat.; Owen, ILoit Led.; Carpenter,
Cotnpar. Anat. ; Gegenbaur, Vergl. Ariat.
1878.

AIR-PASSAGES in plants are large
intercellular passages occurring especially
in the stems of Monocotyledons and in the
leaves and stems of aquatic plants. Their
form and arrangement are sometimes very
regular and elegant, especially when they
depend upon a certain regular peculiarity of
shape in the cells which form the walls of the
passages. Thus cross sections of the com-
mon rush are pleasing microscopic objects,
exhibiting regular stellate cells, the rays of
■which are separated by large air-passages,
giving the spongy texture to the structure.
Large air- passages, communicating with the
stomata, are not unfrequently lined by a
cuticular layer similar to that found upon
the external surface of epidermal cells. In
the Nymphceacete (Water-lily Order) the
large air-passages in the floating leaves and
the stem have peculiarly developed star-like
cells projecting freely into these cavities;
these ceils are filled with a granular sub-
stance very unlike the contents of the large
cells of the general parenchyma of the leaf.
Their nature and oJKce are yet unknown.
The partitions separating the air-cells \\or\-
zontiillYin Lvn7iocha7-is Pli/mien <indAlis7na
planiaf/o form beautiful microscopic objects.
The stems of the Eqtdseta, or Horse-tails,
• present a very regular arrangement of per-
pendicular aii'-passages in the thin walls of

their hollow stems, seen Avell in cross sec-
tions. See Equisetace^.

AIR-SACS in Plants.— The genus Utri-
cidaria, or Bladder-wort, takes its name
from a peculiar sti'ucture of its leaves. The
common species, U. vtdyaris, L., often fouud
swimming just below the surface of the
water, in qiuet streams, is pro^•ided with a
curious floating apparatus, formed by modi-
fication of portions of the feathery leaves,
consisting of small membranous sacs or
pouches, closed, by a valve. The opening of
the pouch is somewhat funnel-shaped ; and
the mouth, as also the internal walls of the
cavity, is fm-nished with curious micro-
scopic glandular hairs. Certain of the cells
contain a blue-colouring-matter, distinct in
its nature from chlorophyll. The valve of
the pouch appears to be capable of opening
inwards only ; so that while it is turgid with
sap, in the vigorous periods of life, it is kept
closed by the pressure of the air apparently
secreted within the pouch ; afterwards the
tissue loses its tension and the air makes
its way out, allowing water to enter, and
thus putting an end to the performance of
the function of the air-sac.

BiBL. Meyen, Secretions-Orf/. d. Pflan-
zen, 1837, p. 12, t. 5. figs. 1-0; Goppert,
Bot. Zed. 1847, p. 721 f Benjamin, Bof.
Zeit. 1848 ; 1 et seq. ; Schleiden, Pmicip.
o/"i?of«???/, Engl, transl. pp. 77-279; Hen-
frev, Elem. Course (Masters), 1878, p. 523;
Sachs, Lehrh. d. Bot., 1874, p. 664.

AIR-TUBES of Insects.— These are horny
tubes found in some insects which live in
water, as the larvse of many Diptera and
some water-bugs (Nepa, Banatra). They
are placed either at the first or last ab-
dominal segment. See Nepa, Culex,
Insects.

AIR-VESSELS inlnsects, see Teacher.
In plants, see Spiral Structures.

ALA'RIA, GreviUe. — A genus of Lami-
nariaceae (Fiicoid Algae), distinguished by
the superficial fructification, arranged in
definite patches on the surface of special
fronds, something like the sori of Ferns.
The patches consist of sporanges resembling
the thecfB of lichens, crowded tdgetlier and
interposed between.perpendicular epidermal
cells. The sporanges of A. esculenta are
described by most authors as pyriforms/jor^s
enclosed in a perispore ; but they perhaps
produce biciliated zoospores like those of
Laminaria. See Laminaria.

BiBL. Harvey, Brit. Mar. Alqce, p. 29,
pi. 3 A ; Grevilie, AUj. Brit. p. 25, pi. 4.

ALBERTIA,

[ 26 ]

ALBUMEN.

ALBER'TIA.— A genus of Eotatoria.
See Albeetina.
ALBERTI'NA.— A fam% of Rotatoria

(Duj.).

Cliar. Body cylindrical, vei'mifonu,
rounded in front, ■with an oblique oritice,
from wliicli the ciliated organ, scarcely
broader than the body, projects, terminated
behind by a short conical tail. Jaws for-
ceps-like, simple or unidentate.

This family contains only a single genus,
and this a single species, A. vermicuhts
(PL 43. tig. 4), -ohich lives parasitically in
the intestines of worms (Lumhrici) and
slugs {Lunaces). Length 1-47 to 1-79".

Within the body are seen ova and young
in various stages of development. The
ciliated apparatus in front of the mouth is
surmounted by a liood-like appendage.

ALBU'JMEX (Chemical). — A proximate
principle of animal and vegetable bodies,
•with, which we are familiar as occm-ring in
the white of egg. It exists in two states,
uucoagulated and coagulated. At a tempe-
rature of 160° F. it is reduced from the
former into the latter condition. It is
reddened by Millon's test ; is insoluble in
acetic acid; is rendered purple by Petteu-
kofer's test, but the reaction requires some
time for its production. In the coagulated
state it is distinguished from fibrine by the
action of acetic acid, and by its insolubility
under prolonged digestion at a heat of
110° F. with solution of nitrate of potash.
When heated with strong muriatic acid, it
is coloured purple.

It possesses no microscopic characters ;
wlien coagulated, it appears to consist of
extremely tine amorphous granules.

ALBUMEN, or PERISPERM (of seeds).
— This is a technical term used in Botany to
denote the cellular structure which exists in
greater or less quantity in all seeds where
the development of the embryo is not accom-
panied by the entire absorption of the
nucleus of the ovule. When the embi-yo
does so displace the nucleus, it becomes
immediately invested by the seed-coats ; in
other cases it is found imbedded in a mass
of cellular tissue of varying structure, which
is the ' albumen.' The structure of albumen
corre?pondsto that of the cotyledons of seeds
devoid of albumen, botli serving the same
office, namely that of reservoir of nutriment
for the germinating seed. This nutriment
may be laid up in different conditions —
namely, in the state of starch, oil, aleurone,
or of cellulose, and in the last case in a soft

and fleshy, or a hard and horny condition.
Combined conditions are often met with in
the same structure, as when a fleshy tissue
contains starch or oil in the cavities of its
cells, >tc.

StarcJu/, meal)/, or farinaceous albumen
constitutes the cliief part of the seeds of
many plants, especially of those of the Grass-
tribe, and is that portion of the corn-grains
whence white flour is obtained. Here the
cellular tissue is composed of membranous
cells densely filled with starch-grains(P1.46.
fig. 3). The edible portion of the cocoa-nut
is the corresponding region of that seed, and
affords us a good example of an oily albu-
men, composed of tolerably thick-walled
cells fiUed with a viscid mucilage, in which
numerous oil-globules are suspended. The
stone of the Date, the nut of the Areca
Palm (PL 47. fig. 21 ), are good examples of
a horny albumen, the cells possessing walls
of extreme thickness, traversed by pores and
formed, like wood-ceUs, by the deposition of
successive layers. In the ripe seed the
structure of this horny albumen is generally
much disguised, and a section exhibits the
appearance of a homogeneous horny sub-
stance excavated into irregular cavities. By
apphdug dilute sulphuric or sulpho-chromic
acid, the true boundaries of the cells may
generally be distinguished, and often even
the lamination of the walls (PL 47. fig. 22).
The substance called Vegetable Ivory is the
albumen of the seed of the Pliyteleplias
Palm, and is an instance of an extreme de-
gree of development of the cellulose albumen,
vying with the hardest woods in the solidity
of its cell-walls. A thin section of this albu-
men, especially if treated with acid, at once
reveals the cellular structure of this dense
substance (PL 47. fig. 23). The true struc-
ture may also be detected by the help of
polarized light (see Polarization). The
cotyledons of many seeds are, as above
stated, formed of elementary structures
resembling those of albumen. We find
them farinaceous, fleshy, or oily, but rarely
attaining to a very great degree of solidity
in the horny forms. The cotyledons of beans
are composed of a fleshy cellidar tissue
with thick, porous walls, coloured blue by
iodine alone (amyloid), while the cavities
of the cells are filled with starch-grains.
The cotyledons of the almond, nut, kc.
are examples of fleshy cells containing
abundance of oil-globles.

The albumen of seeds may be formed by
the development of the tissue of the nucleus

ALCYONELLA.

[ 27 ]

ALDERIA.

of the ovule, in wliicli case it is distinguished
bv some botanists as the epispenn ; gene-
rally it is formed from the cell inside the
embryo-sac, the latter expanding to dis-
place* the nucleus which becomes absorbed ;
such albumen is called endosperm. Some
seeds, such as those of the Nymph asacese,
Piperacte and others, have both endosperm
and episperm, i. e. albumen formed inside
and outside the embryo-sac. The term
jyerisperm is often (advantageously) substi-
tuted for albumen, which has qiute a diflerent
signification in physiological chemistry.

The albumen of seeds is examined by
means of fine sections. In the horny or
bony seeds, the application of solution of
potash or nitric acid is very serviceable in
ascertaining the true cellular structure.

BiBL. Schleiden and Vogel, Nova Acta,
1838, xix. p. 52 (plates) ; Sachs, Botcndk,
1874, p. G81; Heufrey, Bot. (Masters),
1878, p. 154.

ALCYONEL'LA.— A genus of fresh-
water Polyzoa (Bryozoa), belonging to
the order Hippocrepia and family Pluma-
tellidse.

Clior. Tubes branched, adherent to each
other by their sides ; orifices terminal ; ova
(statoblasts) presenting an outer ring, but
free from spines.

Polypary (polypidom) incrusting, and
forming a sponge-hke brown or greenish
mass, attached to submersed wooden posts
&c.

A. stagnorum ( fiim/osci) , PI. 41 . fig. 3.
Polypary indefinite ; orifices of tubes entire,
and without a furrow. Pare.

A. Benedeni. Polypary indefinite ; tubes
emarginate at the orifice, and furnished with
a longitudinal furrow. Rare.

A.flahellum. Polypary fan-shaped ; tubes
prostrate, with a furrow. Rare.

BiBL. Johnston, Brit. Zooph. p. 391 ; All-
man, Polyzoa (Ray Society), p. 80 j Nitsche,
Midi. Archiv, ISOS.

ALCYONID'nD^E (Halcyonellea, Ehr.,
Johnston). — A family of marine Polyzoa
(Bryozoa) of the order Tnfuudibulata, and
suborder Ctenostomata.

Char. Polypary sponge-like, fleshy, of
irregular form; cells irregularly arranged,
immersed, with a contractile orifice ; no ex-
ternal ovarian capsules. Genei'a : —

Akyonidium, Lamx. Erect ; lobed or
simple ; cells pentagonal.

(jijdoum^ Hass. Incrusting, covered
with imperforate papillae ; eggs in circular
clusters.

Sarcochitum, Hass. Incrusting, covered
with perforate prominences in which the
cells are immersed; eggs scattered singly
throughout the poh-jjidom.

BiBL. See the Genera.

ALCYONID'IUM, Lamx.— A genus of
Infundibulate Polyzoa (Bryozoa), of the
suborder Ctenostomata, and family Alcy-
ouidiidse.

Char. Erect, lobed, or simple ; cells im-
mersed, pentagonal.

Nine British species ; they occur attached
to marine objects by a narrow base.

A. gelatinosum. Lobed, lobes subcylin-
drical, surface smooth; attached by a nar-
row base. Deep water.

A. Jnrsidum. Lobed, compressed, surface
papillar from partial protrusion of the
polype-cells. Common.

A. parasiticum. Incrusting, earthy, sur-
face porous.

BiBL. Johnston, Brit. Zoojih. p. 858 j
Gosse, Mar. Zool. ii ; HassaU, Ann. N'. Hist.
vii. p. 370 ; Reid, ibid. xvi. p. 393 ; Tliucks,
Poli/zoa, 1880, p. 490.

ALCYO'NIUM.— A genus of Coelente-
rata or Zoophytes, belonging to the order
Anthozra, and family Aleyonida3,

C/iar. Polype-mass lobed or incrusting,
spongy, containing scattered calcareous
spicula. The skin (ectoderm) coriaceous,
marked with stellate spores ; interior gela-
tinous, netted with tubular fibres and per-
forated with longitudinal canals termina-
ting in the poly]3e-cells, which are subcuta-
neous and scattered. Polypes exsertile.
Marine.

A. digitatum (spicula, PI. 41. fig. 28).
Commonly called ' dead man's toes or
fingers,' and cows' paps. J'orm of poly-
pidom variable, greyish- white or orange-
coloured, skin somewhat wrinlded, stud-
ded over with stellate pores, even with the
sm-face.

Very common, so that on many parts of
the coast scarce a shell or stone can be
dredged from the deep that does not serve
as a support to one or more specimens.

A. glomeratum. Colour deep red; rare.

BiBL. Johnston, Brit. Zooph. p. 174 ;
Gosse, Mar. Zool.-, Gray, Ann. A". Hist.
1869, v. p. 117.

ALDE'RIA, Pritchard. A doubtfid ge-
nus of animals discovered by Alder.

The body of one species (PI. 49. fig. 14)
consisted of a vase- or cup-form, expanded
at the top and furnished with numerous
pointed tentacles, abruptly thickened to-

ALECTO.

[ 28 ]

ALG^E.

wards the base and forming more than one
row. Body attached to a Sertularia by a
tolerably stout stem.

A second species was rather smaller, body
ovate, with a very slender and shortish
stem ; tentacles capitate, not so numerous as
in the first species, and placed in a single
row round a narrow disk.

This was also found on a Sertularia.

A third (PI. 49. fig. 15) was found in
fresh water. Body pear-shaped or, rather,
bell-shaped, with a distinct rim,and a single
row of delicate capitate retractile tentacles ;
stem long and slender. They come nearest
to the o-euus Acineta. Similar orijanisms
ha-i'e been observed by Str. Wright.

BiBL. Trans, of Tifneside Nafuralists'
Fidel Club, i. p. 365 ; Ann. N. Hist. vii.
p. 420 ; Pritchard's Inf. p. 5G2.

ALECTO, Lamx. (Stomatopora). — A
genus of marine Polyzoa, of the suborder
Cyclostomata and family Tubuliporidte.

The species are found upon old shells and
stones from deep water.

A. granulata. Cells in one or occasion-
ally two rows, their walls granular.

A. major. Cells in more than one or two
rows, their walls smooth.

A. dilatans. Branches of polvpary dila-
ted at the ends; cells in several rows, their
walls granular.

Nine other species.

BiBL. Johnston, Brit. Zoopli. p. 280;
Busk, Cat. of Mar. Polyz. (Brit. Mus.) ;
Hincks, rohfzoa, 1880, p. 424.

ALECTO'PtIA, Acharius.— A genus of
Lichens, fam. Lichenacei. Six British
species ; on alpine rocks.

BiBL. Leighton, Lichen-Flora, 1879,
p. 77.

ALEU'PONE (Gluten-flour).— This or-
ganized cell-substance, like starch, is veiy
generally diffused through the A'egetable
kingdom, occurring in the endosperm and
cotyledons of most seeds. It exists in large
quantity in castor-oil and lupine seeds, in
nuts, almonds, cocoa, and coffee-beans &c. It
was long overlooked, on account of its solu-
bility in water. In starchy seeds it consists
of minute granules, of a spherical form,
often pitted on the surface, either solid or
hollow, and covered by a membrane ; while
i 1 oily seeds, the grains are larger and more
complex. They are insoluble in ether, al-
cohol, and fixed oils, but soluble in water,
dilute acids, and alkalies. They are coloured
deep yellow by iodine, and intense red
by carniiue-soluliou. Nitrate of mercury

renders the interior brick-red, but does not
colour the wall. Each granule consists
principally of albuminous matter, but also
contains gum and sugar. In many oily seeds,
as castor-oil, Brazil nuts, kc, the aleurone
gxains contain a crystalloid and a globoid
body. The crystalloids possess angular forms,
and so resemble crystals ; they are not dis-
solved by water or acids, but swell in Liq.
PofassfP, and are coloured yellow by iodine.
The globoids are small rounded masses, not
crystalline, but composed of pliosphate of
lime and magnesia: they are soluble in acids,
but not in alkalies. Sometimes crystals of
oxalate of lime are also met with in the
grains. Aleurone is usually colourless, some-
times green, as in pistachio-nuts, yellow in
Ailanthus-seeds, or blue. It is most easily
examined in a thin section of an almond or
castor-oil seed immersed in oil or spirit.

Fiff. 6 b.

**

Magnified 400 diameters. Magnified 800 diameters.

* Pisiim satiTum, thepardenpea; showing the small
grains of aleurone, and the large starch-grains.

** Cell of Rieinns communis, showing the granular
protoplasm with oil-globules, and the ovoid aJeurone-
grains, containing the round globoids and the angular
crj-stiilloids.

The nutritive properties of many seeds,
as peas, nuts, almonds, &c., depend to a
considerable extent upon the presence of
aleurone. And the solubility of aleurone in
Avater is a point of great consideration in re-
gard to the formation of dietary tables. E'or
if, in boiled peas for instance, the nitroge-
nous proportion is calculated according to
that naturally existing, and the liquor be not
consumed, the diet will be deficient in that
principle to a corresponding degree.

BiBL. Ilartig, Bot. Zeit. 1857 ; Wiesner,
TecJm.Mikr. p. 74, 1807; Sachs, .SoC. p. 52.

ALG^, Sea-tccecls 4't. — This class of
Thallophytes includes the Sea-weeds and
the multifarious greeui vegetable forms of

ALG-E.

[ 29 ]

ALG.E.

simple cellular structiu-e met -with in all
streams, ditches, ponds, or even the smallest
accumnlations of fresh water standing for
any length of time in the open air, and com-
monly on walls or the ground in all perma-
nently damp situations. The great variety
of conditions of organization, all variations
as it were on the theme of the simjjle vege-
table cell, produced by change of form,
number, and arrangement of this simple
element, renders the Algae peculiarly inter-
esting as objects of microscopic research,
even in regard to morphological conditions
alone.

This simple condition of the structures is
here, as in other cases, accompanied by a
delegation of the physiological functions
most completely and fully to the individual
cells ; that is to say, the marked dift'ereuce of
purpose seen in the leaves, stamens, seeds,
&c. of the flowering plants is absent here,
and the structures carrj-ing on the operations
of nutrition and those of reproduction are so
commingled, conjoined, and, in some cases,
identitied, that a knowledge of the micro-
scopic anatomy is indispensable even to the
roughest conception of the natural history of
these plants. Added to this, we find these
plants of such simple structure that we can
see through and through them while hving
in a natural condition, and hj means of the
microscope penetrate to mysteries of orga-
nization either altogether inaccessible, or
only to be attained by disturbing and de-
structive dissection, in the higher forms of
vegetation.

This Class comprehends a vast variety of
plants, exhibiting a wonderfvd midtiphcity
of forms, colours, sizes, and degrees of com-
plexity of structure ; but the subdivision of
them into tkree groups, characterized by
striking external characters, which are
adopted in the classifications of some of the
leading Algologists, facilitates the cursory
consideration to which we are confined here.
These three Orders are theSed-s^wi-ed AJyce
(Floride-e or Rhodospoee^), theZ>«;-A--
spored Algce (Melajstospore^ or Fu-
coiDEJE), and the Green-sporedAkjfe (Con-
FERVOiDE^, or Ciilorospohe^e) — the first
two consisting almost exclusively of Sea-
weeds, the last of marine and more especi-
ally of freshwater plants, the majority of
which are microscopic when viewed singly.

The Algaj are diftereutly distributed by
Thuret, whose researches on their fructifica-
tion have thrown so much light upon this
class, also by Rabenhorst and Sachs, whose

views are referred to under the Orders, and
Vegetable Kingdom.

Order 1. FLORiDEiE or Rhodospore^e,
Almost all marine plants, with a leaf-like or
tilameutous rose-red or purple, rai'ely brown-
red or greenish red, thallus. Fructification
appearing in three forms : — 1. spores, con-
tained in external or immersed definite
masses, mostly enclosed in conceptacles or
cystocarps (ceramidia, coccidia, favelUdia,
&c.) ; 2. tetraspores or tetragonidia, red or
purple, either external or immersed in the
frond, rarely contained in proper concepta-
cles (stic/tidia), each consisting of a trans-
parent membranous sac containing, when
ripe, four spores ; 3. antlieridia, pellucid sacs
tilled with yellow motionless spherical cor-
puscles, collected in masses in situations
corresponding to the spore-fruits. Fertihza-
tion is eSected through the agency of a
style-like filiform process or trichogyne,
with which the sperniatozoids copulate. The
trichogjTie is either only the prolongation
of the cell in which the spores are produced ;
or, more generally, it is supported upon
small cells, which take no direct part in the
formation of the spores. See Floride.^.

Order 2. Fucoide^ or Melanospore^e,
Marine plants with a leaf-like, shrubby,
cord-like or filamentous thallus, of olive-
green or brown colour. Fructification very
varied : — 1. in Fucace^ consisting of mon-
oecious or dioecious conceptacles or oogonia
containing sporanges and antlieridia, the
spores being fertilized by sperniatozoids after
the discharge of both from the parent ; 2. in
Lamiuariacese and allied orders consisting
of definite or indefinite collections of
clavate or filiform sporanges, producing
bicihated zoospores, which germinate di-
rectly ; 3. in Cutleriacea3 of similar spo-
ranges producing zoospores, together with
antheridia, like those of Fucacete ; 4. in Dic-
tyotaceae presenting three forms resembling
those of Floridete, viz. collections of tetra-
spores, oi sporanges containing simple spores,
and of antheridia. See Fucoide^ and
Ph^ospore.e.

Order 3. Chlorospore^ or Confer-
voiDE.E. Plants growing in sea or fresh
water, or on damp surfaces, mostly green,
with a filamentous, or more rarely a leaf-like,
pulverulent or gelatinous thallus ; the last
two forms essentially microscopic, consist-
ing frequently of definitely ari'anged groups
of distinct cells, either of ordinary structure
or with their membrane silicified (Diato-
macete). The green colouring matter con-

ALG^.

[ 30 ]

ALKALOIDS.

sists simply of cliloropliyll in one group,
forming the Chloropliyllophycete of Raben-
horst, as the Desniide;e, Confervse, &c.
While in the other, it exists combined with
Phycocyanine, giving it a bkiish tinge ;
these forming the PliycochromophyceEe of
Rabenhorstjthe Cyanophycese of Sachs, as in
the OscillatoriacesejNustocliacejie, andliivu-
lariaceoe. Fructification varied in its details,
but essentially reducible to three forms : —
1. resting spores produced from the cell-
contents after fertilization, either by Coxju-
GATiON or impregnation by (2.) spennato-
zoicls produced from the contents of other
cells ; 3. zoospores, 2-, 4-, or multi-cUiated
active gonidia, discharged from the vegeta-
tive cells without impregnation and ger-
minating directly ; in some instances these
conjugate (Coxjugatiox). The simple
vegetative increase of the Unicellular forms
is a process essentially analogous to the
cell-division of the filamentous forms, but
results necessarily in multiplication of the
species. The Volvociueaj are remarkable
iox their passing the vegetative stage of
existence in the form of ciliated zoospores,
mostly collected witliinagelatinous common
envelope, or cojnobium, into a definitely
arranged family. See CoNFERVOiDEiE.

Some Algae have been found fossil. (See
Agate.)

Excluded families of Algos : —

CRYPTOCOCCEiE, Kg., containing the
genera Cryptococcus, Kg., Uliina, Kg., and
Sphcerotilus, Kg.

Leptomite^, Kg., containing the genera
Hygrocrocis, Ag., Sirocrocis, Kg., Leptomi-
tus, Ag., Arthromitus, Leidy, Cladophytum.,
Leidy, Mycothamnion., Kg., Erehonema,
Ikomer, Chmnancma, Kg., Nemafococcus,
Kg., ChionipJie, Thienemann, Motilinea, Ch.
Robin, Enterobryvs, Leidy, Eccrina, Leidy.

Ph^oneme^, containing the genera
Stereonema, Kg., Thceonema, Kg., Thceosi-
phonia, Kg.

These consist, for the most part, of aqua-
tic states of MucoEiNi, or of Schizomy-

CETES.

BiBL. Harvey, Brit. Alg(P, 2nd. ed. 18J0 ;
P/iyeol. liritann.; C. Agardh, Syst. Alg.;
J. Agardh, Species ^-c. Algar. ; Kiitzing,
Phycol. generalis ; 8p. Alg. ; Tahuke Pliyc. ;
Phycol. Germ. ; Lyngbye, Hydrophyhdogia
l)anica\ Greville, Alqcv. Brit.; Lerkelev,
Crypt. Bot. p. 84; Henfrey, Elem. Bot.
(Masters) ; Thuret, Ann. d. So. Nat. 1855 ;
Sr Etudes PJiycoJogiques {Anal. d. Algues
inarines), 1878 ; Rabeuhorst, Flora Eurojj.

Algarum, 1865 ; Bornet and Thuret, Ann,
d. Sc. Nat. 1867, vii. p. 166 (Ann. N. Hist.
1867, xix. p. 35), iSf Notes Algologiques, 1876;
Sachs, Lehrb. d. Bot. 1874; Wright, Spicil.
Phycohx/. 1870.

ALIO UL A'RIA, Corda.—
A genus of leafy Liverworts
(see JuNG-ER.MANNiE^), Con-
taining one British species,
common on hedge-banks.

A. scalaris = Jungerniannia
scalar is, Schrad., J. lunceolata,
Eng. Bot. (fig. 7).

Jangerm. compressa, Hook.,
which has stipules only on the
innovations, is included in this Aliuaiana .cala-
genus bv Fries and others. "s. Immature

BiBL." Hooker Brit. Jun- ^^.^eTiJeU'^
germannice, pi. 61 ; Sowerby, gone (magai-
Enr/l. Bot. pi. 605. Se'D-

ALKALOIDS.— The utility of the micro-
scope in distinguishing the more common
alkaloids from each other, has been shown
in an able paper by Dr. Anderson. The
characters consist in the crystalline form of
the alkaloids, and in that of their sulpho-
cj-anides.

The alkaloids are dissolved in dilute
hydrochloric acid, and the dilute solution
mixed, on a glass plate, with solution of
ammonia of moderate strength if the alka-
loid itself is to be examined, or with a
strong solution of the sulphocyanide of
potassium if the sillphocyanide is required,
and at once placed under the microscope.
The only precaution requisite is to avoid
having the solution too concentrated, as the
crystals are then less well-defined than if a
dilute solution is employed.

The power employed should be 250 dia-
meters ; for if a very high power is used, tlie
form of the crystals is not so readily distin-
guished.

Atropine is precipitated in the amorphous
state by ammonia, and not at all by the
sulphocyanide of potassium.

Brucia. A salt of bruciain a sufficiently
dilute state, mixed with ammonia, does not
give an immediate precipitate ; but in the
course of a very short time, irregular star-
like groups of pointed crystals are observed,
as in PI. 11. fig. 1 a. Sulphocyanide of potas-
sium produces a precipitate in tufts of ex-
tremely thin and feathery crystals, which
either radiate from a centre, or present a
sheaf-like appearance. The latter form,
however, is much better marked in the
crystals deposited after st^me hours from a

ALKALOIDS.

[ 31 ]

ALONA.

dilute solution, wliich are still microscopic,
although somewhat larger than those repre-
sented in the ligure (PL 11. tig. 1, h).

Cinchonine is obtained by precipitation
with ammonia in the form of minute granular
masses, made up of more or less distinctly
acicular crystals, radiating from a centre. It
is, hoAvever, somewhat difficult to obtain
them well-marked; and they not uufrequeutly
appear as a confused mass of granules, in
which the radiated structure is very imper-
fectly seen. They form best when the solu-
tions are rapidly mixed (PL 11. tig. 2). With
sulphocyauide of potassium, cinchonine gives
a precipitate consisting of six-sided plates,
together with a variety of irregular crystal-
line masses, and a few rectangular plates
(PL II. fig. 3). When formed by mixing
in a test-tube with agitation, and allowing it
to stand for some time, the crystals are still
microscopic, but much more definite, and
sometimes consist almost entirely of isolated
six-sided tables, of great regularity. The
precipitate dissolves readily in hot water,
and is deposited as the solution cools, in
irregular plates.

Narcotine is precipitated by ammonia in
branched groups of pointed crystals (PL 11.
fig. 4). In concentrated solutions a preci-
pitate is thrown down by sulphocyanide of
potassium, which dissolves readily in hot
water, and is again deposited on cooling.
Under the microscope it is perfectly amor-
phous.

Strychnine. Tlie hydrochlorate, treated
with ammonia, gives an immediate precipi-
tate, consisting of minute prismatic crystals,
all nearly of the same size and very well
defined. Most are isolated, but some cross
each other at an angle of about 60°. When
lying in one position, they exhibit more or
le.ss an appearance of a Saint Andrew's
cross, with a peculiar arrangement of
their terminal facets (PL 11. fig. 5.) The
sulphocyanide consists of flattened needles,
sometimes single, but generally in irregular
groups, as in PL 11. fig. 6. They are either
terminated by a blunt acumination or are
truncated. Those precipitated on the large
scale present the latter forms.

Morphia. Ammonia does not produce an
immediate precipitate in solutions of mor-
phia ; but in the course of a Linger or shorter
period, according to the degree of dUulion,
crystals form, which gradually increase in
size, and po.ssess the form represented in
PL_ 11. fig. 7. Salts of morphia are not pre-
cipitated by sulphocyanide of potassium,

unless the solution is highly concen-
trated.

Quinine. Its solution gives with ammo-
nia a perfectly amorphous precipitate ; with
sulphocyanide of potassium small irregu-
lar groups of acicular crystals, resembling
those produced by strychnia, but longer
and more irregular (PL 11. fig. 8). When
the precipitate is produced in a test-tube,
and with a concentrated solution, it falls
immediately as a white powder composed
of extremely minute needles ; but when
the solution is dilute, it is deposited after
the lapse of twenty-four hours, in crystals
from 1-lth to l-3rd of an inch in length.
See Quininp: and Crystals.

BiBL. Anderson (T.J, Edin. Mn. J. viii.
p. 570.

ALLAN'TOIN.— A crystalline organic
substance found in the liquid of the aUantois
and in the renal secretion of the calf &c.
As artificially prepared, it is one of the
products of oxidation of uric acid.

Its crystals form transparent colourless
needles and four-sided prisms, with mostly
dihedral unequal summits, PI. 10. fig. 20;
not very soluble in either cold or boiling
water, more soluble in alcohol, but not at
all in ether.

BiBL. See Chemistry.

ALLAN'TOIS. — An oblong or pyriform
sac developed during a very early period of
embryonic life from near the end of the in-
testine. Its function is that of a temporary
respiratory organ. The capillaries in the
aUautois of the chick are distributed closely
like those of the lungs of the Batrachia.

BiBL. Wagner, Phys. by Willis ; Miiller,
by Baly ; Carpenter, Hum. Phys. ; Ivirkes'
Pln/s., by Baker.

ALLOMOP.PHI'NA, Reuss.— One of
Peuss's " Cryptostegian "genera of perforate
Foraminifera. It has the appearance of an
irregular Miliola ; subtriangular, with the
chambers in a triple spire and overlapping
so much that only the last three chambers
are visible. The. aperture is a transverse slit
on the inner border of the last chamber.
Fossil in the Upper Chalk and Tertiary of
Germany.

BiEL. Reuss, Denks. Akad. Wien, i. 352 ;
H. B. Bradv, Qu. Mic. Jn. xix. 67.

ALLOT'RICHA, Kent.— A genus of
Infusoria, of family Ox-s-tricLina.

BiBL. Kent, Infusoria, 18S0.

ALO'NA. — A genus of Entomostraca, be-
longing to the order Cladocera and family
Lyuceidas.

ALSOPHILA.

[ 32 ]

ALYCUS,

The three British species may be thus

distinguished : —

, r Shell reticulated reticulata*.

' I Shell striated or grooved 2.

/"Anterior margin of shell nearly

2 J straight, shell brown quadrangularis] .

J Anterior margin of shell convex,

(. shell colourless ovata.

* PI. 19. fig. 4. t PI. 19. fig. 5.

BiBL. Baird, Brit. Eiitomost. p. 131 j
pi. 16.

ALSOPH'ILA, E. Fig. 8.

Brown. — A gejuis of
PolypodiaceousFerns. -^'

Exotic (fig. 8).

Char. Sorighihose, /; ;>;ji.7:;«s:f^>

dorsal, on a vein or in M\

the fork of a vein. »»
Receptacle mostly f^kj/m
elevated, often vil- j^^W^"^^
Ions. Involucre ab- <'Mht'im
sent. Veins simple Alsophiia excelsa.

or furcate, free. Pinnule with sori.

Arborescent, mostly tropical; species
numerous.

Sections of their petioles exhibit fine scala-
riforni ducts, the slits between the fibres
forming many perpendicular rows.

BiBL. Hooker & Baker, Sxjn. FlHc.-p. 31.

ALTERNA'llIA, Nees.— A
genus of Torulacei (Coniomyce- Fig. 9.
tons Fungi). Microscopic fila-
mentous Fungi, remarkable for
their flask-shaped, cellular spores,
produced in cliaius which ulti-
mately break up into the single
links (fig. 9).

A. tenuis grows parasitically fj^i^ (,^3
upon other filamentous Fungi,
and on decaying gourds, and is
common about Berlin, Prague, -^A !ol
and other places. Corda made
the ripe spores germinate on Cla- A ij
dosporimn herharum kept moist. '*■"'
They usually first protruded a
filament from the neck or atte-
nuated projection, and afterwards
others from the cells at the sides
and opposite end of the spore. Alternaria
These tilaments became branched, p ",."[][■>

The Messrs. Tulasne have spon-boar-
shown that Alternaria tenuis is '/Jj*] 'i'"'''^'^"''
merely a state of the common magnified).
Sphccria herharuin,

BiBL. C(n-(la, Ic. Fuihj. iii. p. 5, pi. 1.
fig. 16; Pracliljl. eHr<>2K iSeliiu))nelhil(l .y\. 13;
Tulasne, Fung. Carpoloyia, ii. pi. 32,

ALTEPtNATION of Genekations.

See Generations.

ALTEUTHA, Baird (PeUidiujn, Brady).
— A genus of marine Entomostraca, of the
order Copepoda, and family Cyclopidte.

A. depressa (PI. 19. fig. 3). Eye red.
Found in Berwick Bay, but not common.

A. i7iterrtipta, common ; A. crenatula.

BiBL. Baird, Brit. Fatom. p. 216; Brady,
Copepoda (Ray Soc), ii. p. 158.

AL'TICA. See Haltica.

ALU'CITA. — A genus of Lepidopterous
insects, of the family Alucitidfe.

The species are remarkable from having
the wings divided into six lobes or rays
which are fringed with long narrow scales
resembling hairs, giving them a beautiful
feathery appearance. They are not imcom-
mon in gardens, and sometimes enter out-
houses.

The species of Pterojjhorus exhibit the
same structure, except that the anterior
wings have two, and the posterior three lobes.

BiBL. See Insects (Wings).

ALUM. — This well-known substancecon-
sists chemically of potash and alumina, ^vitll
sulphuric acid and water. Itscry-stals belong
to the regular cubic or tesseral sy-stem, and
usually' assume the octahedral form. When
dissolved in boiling water with slaked linie,
it crystallizes in cubes. The term alum lias
recently been extended to those compounds
in which the potash is replaced by other
bases ; thus we have ammonia-alum,
chrome-alum, &c. The crystals exert no
influence upon polarized light. Common
alum possesses but little microscopic
interest. Its solution is used in some of
the preservative liquids.

AL VEOLINA, D'Orb.— A genus of Fora-
miniferaImperforata,of the family Miliolida
(Carpenter), nearly allied to Orbiculina, but
elongated in the direction of the axis ; Or-
biculina being greatly compressed in this di-
rection. Alveolina rotella (D'Orb., sp.), how-
ever, is nautiloid ; Al. melo, var. a, Ficht.
and MoU, is oblately spheioidal : var. ^,
prolately' spheroidal; Al. ovoidca, D.'Orh.,
elongate-oval ; Al. sahulosa, Montft., fu^^i-
form ; and Al. elonyata, l)'Orb., is sub-
cylindrical.

A. fuslformis (pi. 23. fig. 15) ; A. rotella
(pi. 23. fi'g^. 16).

Buii.. CJarpenter, riiil. Trans. 1850, p,
552 ; Foram. p. 99 ; Parker and Jones,
A72n. Nat. Hist. ser. 3. viii. p. 161.

AL'YCUS, Koch. — A genus of Acarina,
fam. Trombidiua.

ALYSCUM.

[ 33 ]

AMBLYSTEGIU:S1.

A. roseus. Body papillose.

BiBL. Koch, Uchi'i-sivld, &e. ; Murray,
Ec. Entotit. p. loO (tig-.).

ALYSCUM, Duj. — A genus of Infusoria,
of the family Enchelia. Duj.

Al. saltans (PL .30. fig. "8). Colourless,
with faint lonsfitudinal furrows; movement
abruptly jerking; length 1-12(30 to 1-1000".

Found iu infusion of hay, and river-water,
which have been kept.

Bujardin remarks that it differs from
Enchelys nodulosa^ Duj. {Pantotrictim En-
dtehjSj Ehr.), only in the presence of the
retractile cilia.

BiBL. Dujardin, Infvs. p. 301.

ALYS'SUM, Linn. — A genus of Cruci-
ferse (Flowering Plants), possessing elegant
stellate hairs. See H.^ies of plants.

AM.EK^'CIUM, or AMAKOU'CIUM,
M.-Edw. — Agenusof MoUusca, of the order
Tunicata, and family Botryllidfe.

Four British .'•pedes — 2)''"^if''>'"'^'^ (PI- 18.
fig. 10), Nordmauni, Arc/iis, and albicans.

BiBL. M.-Edwards, Mem. s. les Ascid.
Comp. ; Forbes and Planley, Biit. MoUusca,
i. 15 ; Gosse, 31ar. Zool. ii. 33.

AMA'THIA, Lamx. See Sekialaeia.

AMBER. — This substance, found as a
mineral, but strongly resembling iu appear-
ance various gum-resins, is the f os.sil resin of
one or more Coniferous trees belonging to a
vegetation now extinct. It i.^ found in drops,
lamellae, and stick-shaped pieces, the form
and condition depending probably on the
mode and situation of its exudation from the
trees. In many instances the frngments of
amber contain well-preserved remains of the
animals and plants which lived at the period
of its formation, these having been enclosed
by the fluid resin as it escaped from the tree,
in a manner which may be exactly compared
with our mode of preserving microscopic
objectsin Canada balsam. Numerous insects,
Arachnida, and other animals, with leaves,
twigs, fruits, even flowers of plants, have
been described and referred satisfactorily to
their systematic position; and the aid of the
microscope has been largely called in for this
purpose, since the elementary structures are
in many cases perfectly preserved. The
tissue of fragments of Coniferous wood, the
stomata of leaves, and glandular and other
hairs have been recognized ; and besides the
larger Orsqjtogams, Mosses, Jimgermanniaj,
&c., peculiar microscopic Fungi and Diato-
macese have been preserved in a perfectly
distinct condition.

Some of the pieces are cloudy or opaque,

from the presence of numerous minute
cavitiis,varvingin diameter from 1-1000" to
1-100,000" "(Sorby). Some of these con-
tain gas, some liquid, and others both.

The structure of the wood of the Amber-
fir, rinites succinifer, Gopp., approaches
closely that of our Pmi(s Abifs and l\ Fi\rn,
dirt'ering scarcely in any respect but in the
smaller number of the bordered pore.s,
which are of slightly different form.

Two microscopic Fungi preserved in am-
ber have been described and figured by
Berkeley : Penicillium curtipes, and Brachy-
cladium Thomasiimm, a form approaching
C'orefhrojn's of Corda. A third form, de-
scribed at the same time as Slreptotlirix spi-
ralis, he now considers to be an appearance
produced by enclosed bubbles of air.

Ehrenberg detected Diatomacete in am-
ber, namely, Amphora ffravi/is, Coccoiteis
boiealis, Cocconema Cishda, Frayilaria capii-
cina, Navicida affinis, N. AmphioA-ys, K. Ba-
cillam, Pinmdaria capitata, and P. Gasfram.

BiBL. Goppert and Bereudt, Peyenshnrg
Flora, vol. xxviii. p. 545, 1845 ; EJhrenberg,
Ber. Berl.Ak. 1848, p. 17; Berkeley, .¥o?^W.s
in Amber, Ann. JV. Hist. 2nd ser. vol. ii.
p. 380, tab. xi., xii. ; Idem, Crypt. Bot.
p. 303 ; Sorbv and Butler, Mn. Mic. Jn.
xvi. p. 225, 1876.

AMBLY'ODON,Pal. de Beauv.— Agenus
of Funariacefe (Acrocarpous Mosses). The
only species, A. {Br yum) dealbatum, is rare
in Britain.

BiBL. Miiller, Syn. Muse. i. p. 127 ; Wil-
son, Bn/ol. Brit. p. 267.

AMliLYO.M'MA, Koch.— A genus of
Acarina (Arachnida), fam. Ixodea.

Infests cattle, &c. South America, and
Sandwich Islands.

Ijlbl. Koch, Arachnid. ; Mun-av, Ec.
Ent. p. 201 (fig.).

AMBLY'OPHIS, Ehr.— A genus of In-
fusoria, of the family AstasiiTa.

Char, Unattached ; a single (red) eye-
speck ; a simple flagelliform filament, no
tail. One species.

A. viridis { PL .30. fig. 55). Green ; length
1-210 to 1-140".

Anterior end of the body colourless, and
cleft so as to represent a two-lippt-d mouth ;
nucleus near the middle of the body.

Several authors regard this as a Euyleua.

BiBL. Ehr. Infus. p. 103; Duj. Infus.
p. 036 ; Kent, Inf. p. 385.

AMBLYSTE'GIUM, Br. and Sch.— A
genus of Mosses included under Hypnum by
Miiller and Wilson,

AMEIRA,

[ 34 ]

AMMONIA.

AMEI'R A , Boeck. — A genus of Copepoda
(Entomostraca).

A. lonr/ipes. Marine. Nortli Britain.

BiBL. Boeck, Overs. Norr/es Copepoder,
1864, 49 ; Brady, Coijcpoda {Ray Soc), ii.
36.

AMI'BA, Duj. See Amceba.

AMMONIA, IIYDROCHLORATK OR MU-

BiATE OF. — This salt crystallizes in cubes,
octabedra, and trapezobedra. Wben crys-
tallized rapidly it forms curious featbery
aggregations (Bl. 11. fig. 9). Tbe crystals
do not polarize ligbt.

AMMONIA, OXALATE OF. — Tbis salt is
readily prepared by neutralizing a solution
of oxalic acid with ammonia or its carbo-
nate, and evaporating.

It crj^stallizes in long slender needles,
belonging to the right rhombic prismatic
system. When mounted in Canada balsam,
these form a very beautiful object for the
polariscope (PI. 39. fig. 7).

AMMONIA, oxALiTRATE OF ; formerly
known as the lithoxanthate of ammonia.

This salt may be prepared by mixing

1 part of uric acid with 32 parts of water,
and beating tbe mixture in a porcelain cap-
sule until it acquires a boiling temperature.
Strong nitric acid, previously diluted with

2 parts of water, is next added in small
quantities at a time, until nearly the whole
of the uric acid is dissolved. The liquid is
then boiled, filtered, mixed with excess of
solution of ammonia, and concentrated by
eva])oration. As it cools, the salt is depo-
sited in needles or warty groups of crystals.
These are freed from the luother-liquor by
pressure between blotting-paper, dissolved
in w-irm water, and a little solution of fim-
monia added. On evaporation the pure salt
sejiarates.

The oxalurate of ammonia forms one of
the most beautiful and interesting sub-
stances that can be examined by the polar-
izing microscope. When a small quantity
of its aqueous solution is slowly evaiiorated
on a slide, some of it usually crystallizes in
circular crystalloid disks or very flat spheres,
consisting of minute needles radiating from
a centre and in an intimate state of mecha-
nical adhesion ; sometimes the extremities
of tlie needles are seen projecting beyond
the circumference of the disks. The latter
appear colourless or yellowish by reflected
light ; pale or dark brown or even black by
transmitted light, according to their size and
thickness, ^Vben immersed in Canada Ijal-
sam, they become transparent, often nothing

more being distinguishable than radiating
lines, indicating the needles of which they
are composed. But if examined by polar-
ized light and Avith the analyzer, when
these are so arranged that the plane of po-
larization of the analyzer is at right angles
to that of the polarizer (the field being
black ), the disks present the appearance of
beautiful little stars, sometimes almost
white, at others splendidly colom'ed, each
being also traversed by a black rectangular
cross (PL ;]9. fig. II).

On rotating the slide, no change is pro-
duced. But on rotating the analyzer or
polarizer 90°, the arms of the cross appear
to rotate, which, as there are no fixed points
visible in tbe disks, gives rise to the ap-
pearance of the disks themselves rotating.
When the analyzer has been rotated a quar-
ter of a revolution, the former position of the
black cross is occupied by a white one, and
the colours of the intermediate parts become
complementary to (forming white light
with) those which they at first possessed,
these appearances being alternately repro-
duced at each quarter revolution.

If a plate of selenite is placed beneath
the slide, the beauty of the objects is much
augmented (PI. .39. fig. 12). On some parts
of the slide, dendritic aggregations of the
needles are seen (PI. 39. fig. II a).

Sometimes the colours are disposed in
concentric rings ; when these are well de-
fined, a concentric arrangement of the
groups of needles is distinguishable on
examining the disks by common light.

A simple experiment will show the origin
of the cross and tbe colours. If eiglit crys-
tals of any doubly refracting salt be ar-
ranged upon a slide in the directions of
equidistant radii of a circle, they may be
regarded as forming two crosses, alternating
in position. If the slide be placed under
the microscope, with the plane of polariza-
tion of the polarizer and analyzer at right
angles, and the crystals be simultaneously
rotated and kept in the same relati\e posi-
tion, a point will be reached at which each
alternate crystal will become black, the in-
termediate ones appearing coloured ; and im
continuing the rotati(m, th(> crystals which
were at first black vdU appear coloured,
those which were coloured appearing
black.

Tb(i blaclniess of the crystals aiises from
the plane of primitive polarization of the
light transmitted by the polarizer being
parallel with the opticj or neutral axis of the

AlNIxUOXIA.

[ 35 ]

AMCEBA.

crystals, consequently there is no double
refraction and no interference to produce
colour ; whilst in the coloured crystals, the
optic axis of which does not coincide with
the plane of polarization, double refractiou
and interfereuce ensue, by which the colours
are produced. The tint of colour varies
according to the thickness of the disks.
See Circular crystals and Polariza-

TIOX.

AMMONIA, PURPURATE OF, or Murex-
ide. — Is an artificial product of the decom-
position of uric acid. It may be prepared
by dissolving uric acid in dilute nitric acid,
as directed under Ammonia, oxalueate
OF. The solution is evaporated until it
acquires a tile-red colour ; then cooled to
exactly 158° Fahr., and dilute solution of
ammonia added to it until it is neutralized.
Half its bulk of water is then added, and
the mixture deposits the salt in crystals as
it cools.

The crystals form short, flattened, four-
sided prisms (PI. 11. fig. lOj ; they are
ruby-red by transmitted light, and the two
broad surfaces are emerald-green by re-
flected light. They are also analytic.

BiBL. See Chemistry.

AMMONIA, irate of. See Urates.

AMMONIO-CHLOPJDE of Platinum.
See Platinum.

AMffi'BA, Ebr. — A genus of Rhizopoda,
of the order Lobosa, and family Amcebfea.

Char. The same as that of the family ;
but the pseudopodia of one kind only.

These curious organisms constitute the
simplest forms of animal beings ; for they
consist of a single kind of matter, a simple
mass of sarcode. When first placed upon a
slide, they represent minute rounded semi-
transparent masses ; but soon, one or more
rounded or pointed lobes, or transparent
expansions, are seen to shoot out from the
margin. These muve almost imperceptibly
along the slide, and, becoming fixed to it,
slowly diaw the mass toAvards the fixed
point. They are usually found to contain
within them Infusoria, Diatoniacete, Des-
midiacese or other minute Algse wliich are
supposed to serve as food ; these bodies
being involved in the same manner as occurs
in the case of Actinophry's, a temporary
digestive cavity being thus formed. Some-
times vacuoles or contractile vesicles are
seen within them, containing simply the
surrounding liquid ; these contract occa-
sionally and disappear.

Ehrenberg admitted four species j to these

Dujardin added ten, and others have since
been added ; but the characters cannot be
depended upon.

They are found in almost all infusions
which have not become putrid ; also in the
slimy debris covering bodies immersed in
fresh or salt water ; sometimes on moss or
earth.

Their size varies from 1-70 to 1-2800".

Ainceha diffuens is represented in the ex-
panded state by PI. 30. fig. 9 a ; and when
contracted, by fig. 9 b ; fresh water.

A. princeps. Yellowish wlnte, fiUed with
highly refractive granules j 1-50" in diam.
In pools.

A. bicdtce, found in the common cock-
roach, has tbe body striated (probably the
early stage oi&Gregarina).

Amoeba villosa (Wallich) has one part of
the body covered with short processes or
vUli. ^

In many Amcebce, when the pseudopodia
are expanded, the margin of tlie body ap-
pears very transparent, while the inner por-
tions remain granidar ; this has been re-
garded as indicating the existence of an
endosarc and an exosarc. But when a drop
of liq. potassfs is added to an Amoeba, all is
dissolved, except the gTanular matter of the
body, which consists of foreign particles,
oil-granules, &c.

Many so-called Amoebce are probably
early stages of Fungi, &c. ; but in such,
simple structureless bodies, nothing can be
stated certainly, without the use of chemical
tests.

Certain Amoiba-io\'-ms, in which no nu-
cleus or vacuoles occur, have been separated
b}^ Hjickel as Monera ; but since any de-
tached fragment of an Amoeba, or even of
any Rhizopod, will live and form a new
being, it is evident that such characters are
valueless.

Amoeba-like movements of the sarcode or
protoplasm are often perceptible in isolated
normal and pathological structures — as in
the blood-curpuscles, the liver-cells, the
corpuscles of dropsical liquids, the embry-
onal cells of ova, &c. ; also in various vege-
table cells, the root-cells of Chara, Volvox,
the spores of Algae, ,the Myxogastres, &c.
Amaba-\\ke movements may even occur in
dead cells (Lieberkiihn).

An Amoeba with a large cilium and a
villous tail has been described by Carter ;
and a free swimming Amoeba with a ciliiun
by Tatem.

Bill. Ehr. In fits. 12G; Dujardin, Inf.

d2

AMCEB.EA.

[ 36 ]

AMPHIMONAS.

231 ; Auerbacli, Sieb. and K611. Zeitsch.
\ii. 805 ; Schultze, Polythal. ; Carter, Ann.
N. Hist. 18o6 aud 18(14; Wallicb, ihid.
1863, p. 198 ; Broun, Thier-Reich, 1880 ;
Perty, Z. Kenntn. p. 188 ; Tatem, Mn. Mic.
Jn. 1. p. 352 ; Lieberkiihn, Ann. A^. Hist.
1870, Ti. p. 497; Greeff, Arch. f. mik.An.
ii., & X. 1873, p. 51.

AMCEB.^'A, Ehr.— A family of Rbizo-
poda, of tbe order Lobosa.

Char. Animals sbell-less, composed of a
glutinous substance, witbout integument or
internal structure, constantly clianging form
by tbe protrusion and retraction of parts of
tbe body, wbence result variable expansions ;
movement slow.

Tbey are propagated by spontaneous fis-
sion. Wben cut or torn, eacb segment
contracts upon itself and forms a new being.
Spermatozoa bave been stated to be formed
from tbe nucleus, and ova formed from tbe
sarcode,by Carter in Amoeba ; GreelFalso de-
sciibes spermatozoa, but tbese are doubtful.

Gen. : Amoeha. Pseudopodia of one kind.

Podostoma. Pseudopodia of two kinds, —
one large and for locomotion, tbe otber
forming a proboscis, and serving for nutri-
tion.

Petahpus. Pseudopodia cylindrical, ex-
panding at tbe ends into tbin plates.

AMPELOM'YCES, Ces. See Oibium.

AMPHIBLES'TllA, Presl.— A genus of
Polypodiaceous Ferns ; now referred to
Dictyozypldnm and Pteris. — Exotic.

AMPIIICAM'PA, Ehr.— A doubtful ge-
nus of Fossil Diatomacefe.

A. Eruca (PI. 18. fig. 11).

A. mirahilis (PL 18. fig. 12).

Fossil at Tisar, Mexico.

BiBL. Ebrenberg, Ber. d. Berl. Ah. 1855,
86 ; and Mikroq.

AMPlIlDINiUM, CI. aud L.— A genus
of cilio-flagellate Infusoria.

A. operculatum (PI. 53. fig. 2). Marine,
Norway.

BiBL. CI. and Lacbm. Infus. p. 410 ; Kent,
Inf. p. 461.

"AMPIIID'HTM, Nees.— a genus of
Mosses, included under Zygodon.

AMPHILEP'TUS.— A genus of Infusoria,
of tbe family Colpodea (Ehr.).

Eye-spot wanting ; no tongue-like pro-
cess ; proboscis aud tail present.

The so-called proboscis resembles in ap-
pearance a neck. Tlie mouth is situated
beneath the junction of the proboscis and
the body.

Dujardin gives the foiJowing characters.

placing the genus among his Paramecina.
Body elongated, fusiform or lanceolate, nar-
rowed at eacb end, or at least at the anterior
extremity, and furnished with an oblique
lateral mouth.

Tbese animals are usually found in clear
marsh water, and in streams, between
aquatic plants. They are all fm-nisbed with
cilia but one ; in some these are arranged in
longitudinal rows. Species :• —

Amphileptus anser, E. (Dileptus anser,
D.). Colourless ; length 1-120". Proboscis
obtuse, as long as tbe body.

A. margarilifer^ E. and D. Colourless ;
1-72". Proboscis acute, as long as the
body.

A. moniliger., E. and D. Colourless;
proboscis short ; nucleus moniliform ; 1-72
to 1-96".

A. viridis, E. and D, Green ; 1-120 to
1-46".

A.fasciola, E. andD. Colourless; linear-
lanceolate ; 1-720 to 1-144" (PI. 30. f. \0a,
from above ; b, side view).

A. tneleaffris (Loxophi/llunimelear/ris, D.).
Colourless ;_ 1-72" (PI. 31. f. 42 a; b, anterior
portion in side view).

A. loiujicoUis, E. Colourless ; rounded
behind, tapering in front; 1-120 to 1-96".

A. papillosus, E. Yellowish brown ; body
covered with papillfe ; 1-000 to 1-430".

A. vorax, D. i^Trachelius vorax, E.).
Colourless.

A. ovmn, D. (^Trachclius ovittn, E.).
Colourless.

Claparede and Lachmann describe other
species.

See Teachelina.

BiBL. Ehr. Infusionsth. p. 354 ; Dujardin,
hifus. p. 483 ; Claparede and Lachmann,
Infus. p. 3J9; Kent, Infns.^. 523.

"AMPHILO'MA (Fr.'), Nyl.— A genus of
Lichens, fam. Lichenacei.

Char. Thallus white, pulverulent, soft,
submcmbranaceous, containing granida
gonima. Hypothallus bluish-black, tomen-
tose.

A. lanuginosum. On shady mossy rocks,
frequent.

BiBL. Leigbton, Zzc'A.-i^Zora, 1879, p. 156.

AMPIIIM'ONAS.— A genus of Infusoria,
of the family Monadina (Duj.).

Found in kept saline solutions and marsh
water. Species :—

A. dispar. Colourless ; ' length 1-3860 to
1-2700" (PL 30. fig. 11).

A. caudafa (Bodo saltans ?, Ehr.). Co-
lourless ; 1-2180 to lrl270".

A3IPHDI0RriIINA.

[ 37 ]

AMnriSTEGIiNA.

A. brachiata. Colourless.

BiBL. Dujardiii, Infus. p. 292.

AMPHIMOEPIII''NA, Neugeboren.—
Oue of the dimorphous Nodosariiie Forami-
nifera, in which the t)lder portion has grown
on the Froudicularian plan, and the younger
chambers are Nodosariau or Dentahne.
Tertiary, Germany.

BiBL. Verhand. Siebejibiiry. 1850.

AMPHIPEX'TAS, Ehr.— A doubtful
genus of fossil Diatomacese (Cohort Anguli-
feras).

Char. Unattached ; frustides cubical,
solitary, bi\-alve, and pentagonal.

A. PeiUacrinus; diam. 1-240"; Greek
marl.

A. alternans (PI. 25. fig. 11) ; Cuba.

BiBL. Ehrenb. Ber. d. Berl. Ak. 1840
and 1843, Abhl. 1841 ; Kutzing,^«c. p. 1.3G;
Babenhorst, Alg. i. p. 3J 9.

AMPHIPLEU'KA, Kiitz.— A genus of
DiatomacetB (Cohort Amphipleurefe).

Char. Frustules free, straight oi- slightly
sigmoid ; valves lanceolate or linear-laureo-
late, with a median longitudinal line which
is thickened and expanded longitudinally at
each end, but without a median nodule.

The valves appear to resemble those of
Nitzschia in their inecjuality ; but they are
compressed in the opposite direction to those
of that genus, and thus the median hues of
both valves are visible at once. That the
Hues seen upon the frustules are the same as
the median lines of the separated valves, is
e\ident from their exhibiting the terminal
expansions. This view is confirmed by the
sides of the frustules being half as broad
again as the separate valves.

A. pellucida (PI. 16. fig. 7a, side view of
frustule ; b, of valve). Valves linear-lanceo-
late ; length 1-225" ; furnished with longi-
tudinal and transverse strite, of extreme
delicacy, requiring the best object-glasses of
large aperture, and the most oblique light,
to render them visible. Sollitt estimates
them at 125 to 130 in 1-1000". Nelson at
80to 1-1000" longitudinal, and 96tranverse,
(by vertical illumination) : Jn. Mic. Soc. i.
p. -152, 1881), Freshwater: Brit.

A. ri(/ida,K. (sif/t)ioidea,Sm.). Marine;
valves nan-owly linear-lanceolate, slightly
sigmoid ; length 1-150" (PL 16. fig. 7 c, side
view) ; British.

A. Danica, K. Valves lanceolate, trun-
cate ; length 1-400" ; coast of Denmark.

A.injiexa. Marine; linear, lunate, slightly
attenuate at ends, obtuse ; length 1-330" ;
British.

A. Lhidheimcri. Larger tiian A. pell.
in fr.-wat. torrents, N. Amer. (tSrun, Oestr.
Biat. i. p. 469, fig.).

A. Frauenfddii. Indian Ocean, Grun,
ut supra.

BiBL. Kutzing, Bacill. p, 103; Sp. Alg.
p. 88 ; Smith, Brit. Diat. i. p. 45 ; Raben-
horst, Flor. Alg. i. p. 143.

AMPHIPPtU'RA, Ehr.— Agenus of Dia-
tomacese (Cohort Naviculese).

Char. Frustules free, sohtary, constricted
in the middle ; valves convex, having a me-
dian keel, with a nodule at each end, and
either a nodule or stauros in the middle.

Marine, or inhabitants of brackish water.

Frustules sometimes much twisted, oc-
casionally resembUng a violin in form, from
one half of the frustule being in a longitu-
dinal plane almost at right angles to that of
the other. Surface of the valves more or
less distinctly marked with transverse strife,
which under high powers and proper mani-
pulation are resolvable into dots, arranged
as in PI. 15. fig. 8. Many species.

A. alata, E, Common (PI, 16, fig, 8 a
side view ; b, front view), Fr, twisted
fr. view linear, ends rounded ; valves nar-
rowly elliptical.

A. constricta, E. Fr. straight, narrow ;
valves with a transverse line, ends acute.

Babenhorst separates the species with a
distinctly curved, mostly sigmoid keel, in a
genus A?nphka7npa.

BiBL. Ehr. Abh. Berl. Ak. 1841, p. -333 ;
Kutzing, Bacill. p. 107 ; Sp. Alg. p. 93 ;
Smith, ^y-i?!. Diat. i. p. 43, ii. p. 92; Greville,
Mic. Tr. 1863, pp. 1.3, 20 ; 1865, p. 105 ;
Ann. N. Hist. 1865, xvi. p. 5; Gregory,
Diat. of Clyde, p. 33 ; Grun, Verh. Wien,
1860, p. 569 ; Donkin, Qti. Mic. Jn. 1861,
p. 14 ; Rabenhorst, Flora Alg. i. p. 253.

AMPHISTA, Kent.— A genus of Infu-
soria, fam, Oxytrichina,

BiBL. Kent, Inf. 1880.

AMPHISO'RUS.— The compound or
aged individuals of Orbitolifes orbicnlus,
having chambers on both faces of the disk,
are grouped by Ehrenberg under this genus
of his Bryozoa polysomatia.

BiBL. Ehrenberg, Abh. Berl. Ak. 1838;
Carpenter's For. p. 105.

AMPHISTEGINA, D'Orb.— One of the
high-class genera of Forayninifera perforata,
of the Nummuline family. It differs from
Nummulina mainly in not being symmetri-
cal, one face being more conical than the
other. On the flatter face the alar flaps of the
chambers are as in Nummulina ; but on the

AMPinSTOMA.

[ 38 ]

AMYLOBACTER.

other they are packed in around the umbo
among the chambers, to which they are at-
tached by very narrow necks. The aperture
also lies somewhat on this side of the me-
dian plane. Living abmadantly in some
parts of the tropical seas ; and found fossil
m some Tertiary strata younger than those
rich in Nummulites. Recent, South Seas ;
fossil, Middle Tertiary, Australia, Europe.

Amphistegina Haueri (PI. 24. fig. 38).

BiBL. D'Orbigny, For. Foss. Vien. ; Car-
penter, Foram. p. 241.

AMPinS'TOMA (Holostotnum, Diplo-
disciis). — A genus of Entozoa of the family
Trematoda.

Char. Body soft, oval, cylindrical or co-
nical ; intestine 2-branched ; two pores, one
anterior, the other posterior forming a large
sucker.

The species are numerous, most common
in birds, but sometimes occur in mammalia,
reptiles, and fishes ; general!}^ inhabiting the
alimentary canal ; length from 1-10 to 4-5
of an inch.

A. homim's, in imm (India) ; near the ileo-
colic valve; red; ^" long.

BiBL. Dujardin, ^e/?H. p. 327; Diesing,
Si/sf. Jlchn. ; Proe. Asiat. Sue. 1876 ; Col)-
bold, Paras. 1879, p. 37 (fig.).

AMPHITET'RAS, Ehr.— A genus of
Diatomacese (Cohort Anguliferfp).

Char. Side view of the f rustules rectangu-
lar, the angles sometimes produced ; valves
covered with depressions, which are readily
seen imder a low power.

This genus approaches Isthmia and Bid-
dulphia, from which it differs in its rectan-
gular and not compressed figure.

A. antedUuviana (PI. IG. fig. 9) ; a, frus-
tules united ; h, side view ; c, front view ;
d, perspective view. Lateral surfaces of
the frustides with concentric radiating de-
pressions, their sides concave. British ;
marine.

A. adriatica. Depressions concentric
and radiating : angles of the frustules ol>
tuse ; lateral surfaces of frustules Avith
straight sides ; Adriatic sea.

A. parallela. Depressions parallel ; in
Greek marl.

10 other species.

BiBL. Kvitzing, Bacill p. 135 ; Sp. Ahj.
p. 133 ; Ehrenberg, Ahh. d. Perl. Ak. 1839,
pp.122, 144; Greville, M(c. Traiis. 1805,
p. 105, 1866, p. 9; Rabenhorst, Fhr. AUj.
i. p. .818.

AM'PIIITHRIX, Ktz.— A genus of Ri-
vulariaceous Algse ; consisting of erect,

tufted, flagelliform filaments ; with crowded
fine articulated fibrils at the base. On wet
rocks, the sides of aquaria, &c. ; fr. water.

A. papilhm (PL 3. fig. 4).

BiBL. Rabenhorst, Alg. ii. p. 229.

AMPHIZONEL'LA, Greeff.— A genus of
Rhizopoda=-(4wi(E6a with a very delicate
shell.

3 species ; fresh water.

BiBL. Greeff, Arch. f. mik. An. 1866, ii.
p. 323 ; Broun, Klass. pi. 1. fig. 7.

AM'PHORA, Ehr.— A genus of Diato-
maceee (Cohort Naviculete).

Char. Frustules solitaiy, free or adherent;
valves with a nodide or a stauros at the
middle of the margin on the inner side.

The nodules exist on the flat side of the
frustules ; the fr-ustules are plano-convex ;
PL 16. fig. 10 a represents a transverse sec-
tion ; the side view of the frustules can only
be seen when these are made to roll over
by sliding the glass cover upon the shde
with the mounted needle. (Inteoduction,
p. xxiii.)

Tlie vahes are furnished with transverse
strife, resolvable into dots, but iu some spe-
cies these are excessively minute.

The species are both marine and aquatic.

A. oralis, K. Aquatic; frustules turgid,
oval, ends rounded or truncate ; length
1-400"; common. (PL 16. fig. 10, front
view; 10 a represents a transverse secticm.)

A. mi7ititissima, S. Aquatic, adherent to
other Diatomacese ; valves with a stauros :
length 1-1200".

A. costata, S. Marine ; ends beaked ;
valves longitudinally ribbed ; length 1-500".

A. membranacea, S. (PL 16. fig. 11);
brackish water.

Rabenhorst describes 54 European and
22 other species.

BiBL. Kiitz. Bacill. p. 107 ; Sp. Alq. p.
93; Smith, Brit. Diat. i. p. 19 ; Rabenhorst,
Flor. Ah/, i. p. 86.

AMPHOROPII'ORA, Buckt.— A genus
of Aphidas.

A. amimllata is very large, green ; eyes
red, with very long antennae fixed on "the
fi'ontal tubercles ; cornicles large, dilated in
the middle, with black trumpet-shaped
orifices. On Cystopteris montana.

BiBL. Buckton, Aphides (Pa)/ Soc),
1879, L p. 187. ^'

AMYLOBACTER, Tr.5cul.— The orga-
nisms to which this name has been applied
are obtained by macerating tlie stems of
plants of various families in water. They
are round, or oval, of);en bacillar and capi-

AMYLOID.

[ 39 ] ANALYTIC CRYSTALS.

tate ; about 1-50,000" in lonj^th (PI. 53.
fig. o). Tliey are formed Avitliin the latici-
feroiis vessels, but also within cells or fibres,
and between the cells. They are coloured
yellow by iodine, sometimes purple by sul-
phuric acid. They seem to correspond to
amylaceous Bacteria. They sometimes ex-
hibit rapid movements. Their formation
witLiu closed spaces has raised the question
of spontaneous generation.

BiBL. Trecul, Compt. rend. 1865-7-8;
Nvlander, Flora, xxxviii. 522, 1865 ; Robin,
iyVcr.881; v.Tieghem, Btdl.S. hot. Fr.xxiv.

AM'YLOID. — This name was given by
Schleiden and Vogel to a peculiar moditica-
tion of ATgetable substance met with in the
thickening layers of the cell-walls, in the
cotyledons of certain Leguminosse, viz.
Schofia spenosa, S. latifolia, Hj/mencea
Courbaril, 3Imuna vrens, M. gigantea, and
ihe tAmsxmdi {Tamarindus indica) ; also of
the common white Haricot bean. When
in a dry condition, it is of a soft horny con-
sistence ; when wetted, it softens, becomes
gelatinous and ti'ansparent ; it is soluble in
boiling water, strong acids, and in solution
of potash, but not in alcohol or ether. It is
coloured blue by iodine, like starch, the
compound being soluble in water with
change to a yellow colour. The 'amorphous
starch,' described by Schleiden, in the seeds
of Cardamomum viiims, in the rhizomes of
Carex arenaria and Sarsaparilla, seems
scarcely distinct fi-om amyloid ; it forms a
thick viscous layer lining the cells. Amyloid
forms a transitional substance between
starch and bassorin and cellulose, and pro-
bably presents modifications approaching
more nearly to one or other of them in dif-
ferent plants.

When cellidose is treated with a mixture
of 4 parts of sulphuric acid and 1 of water,
it swells into a clear jelly, which is at first
stiff", but gradually acquires liquidity ; alco-
hol or water throws down from it white
flakes of amyloid, which are colom'ed blue
like starch hy iodine. It differs, however,
from starch in the circumstance that the
iodine can be washed out of it, and the blue
colour made to disappear by the action of
water, which is not the case with starch.

The so-called Amyloid substance of Vir-
chow consists of a nitrogenous matter,
closely allied to albumen. It is coloured
deep reddish-brown by iodine, the addition
of sulphuric acid sometimes producing a
bluish-black or violet tint. It occurs intis-
seus and organs affected with the waxy or

Jardaceous degeneration, as the small arte-
ries, the liver, the kidneys, the spleen, and
the lymphatic glands.

See Cellulose and Starch.
AMYXCJM. See Starch.

AMYMO'NE, Glaus.— A genus of Cope-
poda (Entomostraca).

A, sphcerica and longhnana. In dredg-
ings.

BiBL. Brady, Copepoda (JRay Soc), ii. 28,

ANABAI'NA, Bory. SeeTRicHORMUs.

ANACALYP'TA, Rohl.— A genus of
Mosses, made a section of Pottia by MiiUer.

BiBL. Miiller, Syn. Muscor. i. p. 5J7;
Wilson, Bryol. Brit. p. 97.

ANACH'ARIS, Rich.— A genus of Hy-
drocharidaceaa (aquatic Monocotyledonous
Plants). A. Alsinastrujn, Bab., which is
apparently identical with TJdora canadensis,
a North-American plant, has become widely
diffused in Britain during the last few years
in ponds and streams. It is of great interest
to microscopic observers, on account of the
facility with which the Rotation of the
cell-contents may be observed in its living
tissues. It is commonly cultivated in jars
of water for this purpose.

BiBL. Wenham, Qu. Mic. Jn. iii. p. 277.

ANAL'GES, Nitzsch. — Agenus of plumi-
colous Acarina, fam. Sarcoptidae. In the
species, the integument is striated ; the 3rd
pair of legs very large and long j the abdo-
men entire.

Five species ; on birds.

BiBL. Megnin, Parasites, 1880, p. 149,
pi. 6.

ANACYS'TIS, Meneg.— A genus of
Palmellaceous Algse ; consisting of very
numerous spherical green cells, imbedded in
mucus, and enclosed in a lamellar envelope.

A. marginata (PI. 52. fig. 8*). Found
floating in fr. wat. pools, or on other algte.

A. Grevillei, on dead stalks of asparagus.
Other species.

BiBL. Kiitz. Tah. Phycol.i. pi. 9. figs. 2-4;
Sp. Alg. p. 209 ; Berkeley, Gleanings ^-c. ;
Hassall,i?/7V.^/(/.(Cc»ccoc/t^ons);Rabenhorst,
Fl. Alg. ii. p. 52.

ANALYTIC CRYSTALS.— A term
proposed by Fox Talbot, in 1837, to desig-
nate those crystals which possess the power
of analyzing polarized hght, like the tour-
maline. The substances in which this pro-
perty is best exhibited are the nitrate of
potash, the sulphate of chrome and potash
dissolved in tartaric acid by heat, boracic
acid, the oxalate of chromium and potash,
allantoin, hippm-ic acid, urea, oxalate of urea,

ANALYTIC CRYSTALS.

40 ]

ANAULUS.

uric acid, Sec. They must be immersed in
Canada balsam. The cryi^talline compound
of disidphate of quinine with iodine is infe-
rior to none in this power. The phenomena
scarcely need description, since analytic crys-
tals merely play the part of a thick plate of
tourmaline, or a Nicol's prism : i. e. if polar-
ized light be transmitted through them (a
polarizer alone being used), in one position
they sutler it to pass freely, while if they are
rotated 90° they arrest or absorb it entirely,
or to a greater or less extent : and if a plate
of selenite, or other depolarizer, be placed
beneath the slide upon which the crystals
are situated (without the analyzer) the lat-
eral surfaces are seen to be coloured, the
complementary tints appearing at each
quarter rotation.

Of course these crystals will act equally as
polarizers and analyzers. Fox Talbot gives
the following explanation of the cause of the
phenomena in the crystals which he exa-
mined. When a beam of polarized light is
transmitted very obliquely through a small
prism of nitre, its outUne generally exhibits
two colours instead of one ; for while the
edge of the prism, which is on that side
from which the ray of light comes, is, for
instance, red, the opposite edge will appear
green. On reversing the polarization of the
light, these colours are exchanged. This ob-
servation shows why the phenomenon only
occm'S in crystals possessing strong double
refraction, like nitre, in which the refractive
indices of the two rays are materially dif-
ferent. When a ray of common light is in-
cident upon such a crystal, and therefore is
divided into two rays oppositely polarized,
both rays are transmitted through the cen-
tral parts of the crystal, which are bounded
by parallel planes, or by planes approaching
to parallelism. But when tlie bounding planes
of the crystal are much inclined to each other,
and therefore refract the light in the manner
of a prism, the refi'active indices of the rays
mav diflPer so much, that while one passes free-
ly through such a prism, theothercannot pass
at all, but suffers total internal reflection,
and is thereby dispersed ; just as if the prism
had a larger "^reflecting angle with respect
to that ray than to the other. Therefore if
two op])ositely polarized rays are presen-
ted to such a crystal as in our experiment,
one will be transmitted and the other not.
That this is the true explanation appears
from this, that when the obhque planes are
well-formed and clearly defined by the mi-
croscope, the colour also is accurately limited

by the same boundary ; so that while this
part analyzes the tints of a plate of sulphate
of lime, the rest of the crystal is inactive.

That internal reflection and dispersion,
however, are not the cause of the separation
of the coloured rays, is shown by the fact
that those lateral surfaces of crystals which,
when viewed through the microscope (with
the polarizer and plate of selenite alone ), ap-
pear of a certain colour, say green, exhibit
the complementary tint, red, when viewed
with the naked eye from the side of the
stage ; hence the two coloured rays are se-
parated merely by refraction.

The margins of cavities containing air and
air-bubbles, which sometimes exist in the
crystals, exhibit the colours in the same
manner and from the same cause as the
lateral oblique surfaces of the crystals.

Nothing can sui'pass the curious and beau-
tiful appearance presented by analytic crys-
tals, the delicacy and briUiant transparency
of their coloured margins giving them the
aspect of figures drawn ^"ith coloured ink.

PL IL fig. 11 a, ft, represent two crystals of
nitre, viewed with the polarizer but with (.)ut
the analyzer or the plate of selenite; fig. 12
a, 6, represent two crystals as seen when the
polarizer and jilate of selenite are used, exhi-
biting the complementary colours; fig. 12 c
represents an air-bubble enclosed in the crys-
tal. See DiCHROiSM and Polarization.

BiBL. Brewster, P/nl. Trans. 18.3.5 ; Fox
Talbot, ibid. 18.37.

ANAliTIIROP'ORA, ^m\ti,= Lejmilia
part.

A. monodon=Lepr. man. ; on stones from
deep-sea water.

BrBL. Hincks, Pohjzoa, p. 232.

ANAU'LUS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, compressed, sub-
quadrate, not furnished with either tubular
processes, nodules or aperturesi, but ha\ ing
lateral constrictions.

In the latter character it resembles Bid-
dulphia.

Kiitzing admits one species : —

A. scalaris, Ehr. (PI. 18. fig. 7). Valves
turgid in the young state, very broad and
flat when mature; having 4, G, 8, or 14
lateral constrictions, which give the front
view a ladder-like appearance; marine; dia-
meter 1-470 to 175". Antarctic Ocean.

A. indicus, Ehr.= Terpsinoe indica, Kiitz.

BiiJL. Ehrenberg, Ber. d. Berl.Ak.l8U,
p. 197; 1845, p. 3l3l; Kiitzing-, -S^^. Ala. pp
119, 120.

»

ANBURY.

[ 41 ]

ANEMIA.

AN'BURY, or Ambury, popularly club-
root or tingers-and-toes, is a di.sease peculiar
to the Brassicacete. It consists in the for-
mation of galls or warts, often of large size,
on the lower part of the stems and the
roots. It has been attributed to various
causes : in some instances, the larv8e of a
weevil have been found within the galls, to
which their origin might fairly be attribu-
ted. The Aphidaj have also been supposed
to produce these tumours; this Buckton de-
nies. The later researches of Worouin have
ti-aced this disease to the agency of an ally
of the Myxomycetes, called Plasmodiophora
Brassiccp.

BiBL, Johnson, Gordener^s Diet. p. 31 ;
Buckton, Aphides {Ray Soc), ii. p. 20;
Worouin, Priiif/sheim Jahrb. xi. p. 548 (pis.).

AXCHOREL'LA, Ouvier.— A genus of
Crustacea, of the order JSiphonostoma.

Cliar. Body short, produced in front into
a Ivind of neck, which is transversely rugose ;
arms two, furnished with a sucker or adhe-
sive disk at the end, and contlueut through-
out their length.

Two British species —

A. uncinata (PL 19. fig. 7), milk-white ;
found on the gills and gill-covers of the cod,
haddock, and whiting; length about 1-2".

A. rugosa, found ou a species of cod;
length about 1-3".

I'he above characters refer to the female.

BiBL. Baird, Brii. Entom. p. 336.

ANCYR'IUM, Werneck. — An obscure
genus of Infusoria.

Char. That of an Enterodelous Bodo, with
a moveable setaceous foot.

6 (?) species.

BiBL. Wemeck, Ber. d. Bed. Ak. 1841,
p. 377.

ANCHYLOS'TOINIA, Dubini.— A genus
of Nematoid Entozoa.

A. duodeNali'i=Uochmit(s duod.

A. di/sent erica (PI. 53. tig. 4) is of doubt-
fid position. It is about 1-100" in length ;
cuned and transparent in front, yellow and
opake behind, and expanded at the base. It
is tirmly attached to the mucous membrane
in large numbers ; and occurs in the dejec-
tions of diarrhoea and dysentery in hot cli-
mates.

BiBL. Douuon, Parasites ^-c. 1877; Beau-
regard, Mic. 1<*>80, p. 610.

ANCYRO'MOXAS, Kent
flagellate Infusoria, fam. Monadidte.

Char. Ovate or elongate, free or adherent ;
flagellum single, trailing at the end, vibra-
tile elsewhere; a nucleus and vesicle present.

A genus of

A. sigmoides, among decaj-ing Fueus,
Jersey ; length 1-5000".

BiBL. Kent, Infiis. p. 247.

ANCYS'TR0PU8, Kohl.— A Pferoi)tus,
found on Egyptian bats; dull yellow, with
blackish markings, legs brown. JNIurray,
Ec. Ent. p. 180 (tig.).

ANDRzE'A, Ehr. — A genus of Mosses.

See ANCRiEACEiE.

ANDR.'EA'CE^-E.— A family of Schisto-
carpous Mosses, characterized especially by

Fig. 10.

Fig. 11.

Fig,
Fig

Andraea rupestris.

10. A sporange not yet open.

11. A sporange burst into four valves, united at

their points. Magnified 20 diameters.

the peculiar mode of splitting of the fruit,
somewhat analogous to that which is found
in Ju7}germaimia, the urn-shaped capsule
di\-iding perpendicularly when ripe into
four or eight valves, which usually remain
attached together at their points (figs. 10
and 1 1) . But the capsules always differ from
those of Jungermannia in the presence of a
columella. The cells of the leaves are pa-
renchymatous, with their walls thickened,
and somewhat papillose on the surface. The
calyptra at first covers the capsule entirely,
then splits off" as a mitre-shaped or bell-
shaped cup. The archegonia and antheiidia
are either on the same or distinct plants,
and the latter terminal on distinct branches.
The few British species are natives of rocky,
usually alpine
districts, and
belong to the
^&a.\x&Andrcea.
In Acrochis-
ma, an antarc-
tic genus, the
sporange splits
only part of
the way down.
BiBL. Wil-
son Brilol. Group of sporanges bursting to dis-
r. I, •-,-,' charge the spores. Magnified.

Britann.^.W.

ANE'MIA (v4?2(»? /ma), Swartz. — A genus
of Schizseaceous Ferns (fig. 12),

Anemia mandioccana

ANELLLDA.

[ 42 ]

ANGUILLULA.

Char. Capsules small, very abundant,
forming a copiout<ly branched panicle.

Several species 5 _mostly from trojDieal
America.

The fertile frond.s, bearing the sporangia,
are reduced to mere ribs.

BiBL. Hook. Sp. Filic. p. 431.

ANEL'LIDA. See Annulata.

ANEU'RA, Dumortier

Pelliese (Hepati-
cse), gi-o wing in wet
places, containing
3 British species.

A. pinguis, L.
Frond irregularly
branched, margins
sinuate, calyptra
smooth, whole
plant brownish-
green. = J", phif/ut's,

Hooker,

Br.
46

Jun-

germ.
13).

A. multijida, L.
Frond bipinnately
divided, calyptra
tuberculate. = J.
mnltijida, Hooker,
Br. Juugerm. t.
45 (figs. 14 and
15).

Fig. 14.

K^

Aneura pinguis.
Burstinp; sporanges. Magni-
fied 2 diameters.

Fig. 15.

Aneura muUiflda.

Fig. 14. Portion of a frond with young perichsetes,

magnified 20 diameters.
Fig. 15. A periehffite, more magnified, cut open to

show the archegonia.

A. palmata, Nees. — Frond palmate, ca-
lyptra tuberculate, =/. multijida, var. jyal-
mata, Hooker.

BiBL. Hooker, Brit, Jungermannice ;
Sachs, Bot. 1874, p. 355.

ANGIOP'TEEIS, Hoffmann.— A genus
of Marattiaceous Ferns. Exotic.

BiBL. Hooker, Sp. Fil. p. 440 (\^\. 0).

ANGUIL'LULA, iMiiller {lihahditis,
Duj.). — A genus of animals, formerly placed

among the Infusoria, but arranged in the
order Nematoidea of the class Eutozoa by
modern zoologists. The popularly known
" eels ■' in vinegar and paste belong to this
genus.

Char. Body filiform, narrowed at the
ends ; mouth terminal, round, naked ; anus
subterminal ; tail of male either naked or
furnished with a membrane (winged); a
double spiculum ; tail of female conical,
acute. Mouth succeeded by an oblong ca-
vity (pharyux) ; stomach top-shaped or
spherical, ftu'nished with a kind of dental
armature. Tail of the female fi-equently
prolonged into a fine point. Uterus bitid ;
vulva situated near the posterior third of
the body. Oviparous or viviparous.

These animals are especially remarkable
and interesting on account oif their great
tenacity of life ; resembling in this respect
the Tardigrada and Rotatoria. Thus Ang.
flutiaiilis, when existing in places exposed
to the heat of the sun, will dry up and be-
come hard and brittle. But as soon as re-
moistened by rain, it revives, swells up, be-
comes soft, takes food and exercises its re-
productive functions as before. The same
faculty is possessed to an extraordinary de-
gree by Aug. tritici, which will revive after
having been kept in a dry state for more
than five years. Nor are they destroyed by
being frozen.

A)ig. fluviatilis (?) (Ang. terresfris, Duj.)
(PL 21. fig. 4). .White" about 15 times
as long as broad ; cesophagus fusiform, ex-
panded posteriorly so as to become contimi-
ous with the much larger stomach; length
of male 1-50 to 1-12".

Found in wet moss and moist earth,whence
it gets washed into rivers and ditches;
sometimes also in the intestinal canal of
snails, frogs, fishes, worms, and insects.

Am/, aceti (PI. 21. fig. 5). From 30 to
45 times as long as broad, narrowed poste-
riorly and terminated by a drawn-out point;
cesophagus cvlindrical; tail conical, pointed;
length 1-30 to 1-17".

This species was formerly very common
in vinegar, and tlie " eels in vinegar " were
favourite popular microscopic objects. To
the freedom of our vinegar from mucilage,
and the addition of sulphuric acid allowed
by law, must be attributed their compara-
tive rarity in the present day. Still, if to
clieap vinegar, in which a few may be per-
ceived by a haiid-lens, a little flour be added,
thev mav be bred in swarms.

Ang. tritici (V\. 21. fi^. G). 20 times as

ANGUILLULID^.

[ 43 ]

ANGULAR APERTURE,

long as broad in the adult state ; length
1-42 to 1-4"; pharynx with an exsertile
epear, trilobed at the base.

Found in blighted wheat, and sometimes
infesting the young plants, burrowing in the
leaf-sheaths, where we have found them re-
producing by ova, in great numbers.

Aiiff. gluiinis. About 20 times as long
as broad, terminating posteriorly in a fine
elongated point; length l-lo".

Found in sour paste.

Other so-called AmjuilMcs are found in
the same situations as A. Jluviatilis, See
Enoplid^.

Aug. {Leptode7-d) stercoralis is a simple,
smooth-bodied nematode 1-G25" long;
somewhat narrowed in front, and more so
behind ; the males and females being nearly
equal in size. Found in enormous num-
bers in the evacuations of patients in Cochin-
China.

Ang. {Lept.') intestinalis is a larger spe-
cies, sometimes found with the above, but
less numerous; length 1-11", breadth
l-7o7;'.

It is almost impossible to dissect these
minute beings in the ordinary manner ; the
best method of proceeding is to wound the
body, and gently press out the contents
under water.

BiBL. Duges, Ann. Sc. Nat. 1826, ix. ;
Bauer, PJiil. Tr. 182.3 ; Ehrenberg, Symhol.
Phys.; Dujardin, Helminthes \ Davaine,
Ann. N. H. 18o6, xviii. p. 2(38; Bavay,
ibid. 1877, xix. p. 350 ; Kiihn, Sieb. & K61-
liker's Zeitsch. 1857, p. 129; Bastian, Linn.
Tr. 1805, XXV. 73; Cobbold, Entozoa, 1879,
p. 236 (figs.).

ANGUILLU'LID^.— A family of ne-
matoid worms.

This family corresponds pretty nearly to
the Enoplidse of Dujardin. The genera
have been re\'ised by Bastian in an excel-
lent monogTaph, in which several new
genera and 100 new species are described
and figured; to which we must refer those
who are specially interested in this curious
group.

A small nematoid is very destructive to
young cucumber plants, forming cysts in
the roots. M. Cornu has recorded a similar
disease in the Rubiacefe. The genus to
which these nematoids belong has not been
determined.

BiBL. Bastian, ZmM.r;'.xxv.p.73, 1865;
Cornu, Compt. rendus, 1878-9 ; Beauregard,
Mic. 1880, p. 604.

ANGUINA'RIA,Lamk.(^ETEA, Lamx.).

— A genus ofmarinePolyzoa,ofthe suborder
Cheilostomata, and family Kucratiida^.

Char. Cellstubular, erect, scat tered,rising
from a creeping fistular fibre adnate to a
foreign base; aperture terminal or subter-
minal. British species : —

A. Sj)afulata. Cells spatulate at the end,
curved, ringed.

A. recta. Cells straight.

A. triincata. Cells truncate at the end,
surface punctate, not ringed.

Fom- foreign species.

BiBL. Johnston, Br. Zooph. 292 ; Gosse,
Mar. Zool. ii. 13 ; Busk, Cat. Mar. Pohjz.
31 ; Hincks, Polyz. 1880, p. 2.

ANGUINEL'LA, V. Bened.— Agenus of
marine Poh'zoa, of the suborder Ctenosto-
mata, and family Vesiculariidse.

A. puhnata. Palmately branched, largely
composed of mud; tentacles 12; no gizzard;
British.

BiBL. Gosse, Mar. Zool. ii. 22 ; Van
Beneden, Bryoz.; Hincks, Mar. Polyz. 1880,
p. 539.

ANGULAR APERTURE.— The angu-
lar aperture of an object-glass is the angle
measured by the arc of a circle, the centre
of which is formed by the focal point of the
object-glass, the radii being formed by the
most extreme lateral rays which the object-
glass admits.

Thus let fig. 16 represent a perpendicular
section of the lowest combination of an
object-glass of small aperture : a is the

Fig. 16.

Fiff. 17.

angle of aperture ; and /, e are the most
oblique I'ays which the object-glass will
admit ; the angle is measured by the dotted
arc b. In the object-glass of larger aper-
ture, fig. 17, the arc b which measures the
angle is much larger, and the radii repre-
senting the extreme lateral rays are much
more oblique. Hence it is evident that the
object-glass of larger aperture admits all

ANGULAR APERTURE. ' [ 44 ] ANGULAR APERTURE.

those rays admitted by tliat of less aperture,
and a certain number of other rays, these
being more oblique.

Mcasnrcmoit of the migle of aperture. — It
is of the utmost importance to know the
angle of aperture of the object-glasses used
in investigations ; because the appearances
presented hy objects vaiy according to tlie
magnitude of this angle, and this variation
must always be taken into account in de-
termining the structure of an object from
its appearance. A particular piece of appa-
ratus is requisite for this purpose (fig. 18),

which may easily be constructed as follows.
A rectangular piece of board must be pro-
cured, the shortest sides of which are about
2 inches longer than the body of the micro-
scope, and the longer sides twice this length.
A small hole must then be made opposite
the middle of one of the long sides, at about
half an inch from its margin, and from this,
as a centre, a semicircle must be traced
upon the board, and the semicircular line
divided into 180° ; the portions outside the
semicircle being cut away. The wooden
plate of this form is shown in perspective in
the woodcut. A fiat thin piece of wood («)
rather broader than the body of the micro-
scope, a little longer than the radius of tlie
semicircle and pointed at one end, is then
placed upon the board in such a manner that
the pointed end corresponds with the gra-
duated margin, wliilst tlie other end is
transfixed by a pin (h) wliich below is driven
into the ])oard. Tluis we have a rotating
arm or radius of the semicircle, which may
be compared to the hand of a watch or clock,
the pin forming the centre of rotation. To
the upper surface of this arm are glued two
thin pieces of wood, excavated in the
middle, so as to form supports for the body
of the microscope ; the excavations should
be triangular, the apex being directed down-
wards.

Wlien used, the object-glass to be tested
is screwed to the end of the body next the
pin, and so adjusted that its focal point is
as nearly as possible perpendicularly over
the pin. A lamp is placed 2 or 8 yards
from the board and upon exactly the same
level as the axis of the body of the micro-
scope, the straight side of the board being
next the lamp ; and when the arm has been
so adjusted that the pointed end is opposite
90°, the lamp is placed so that the flame is
seen through the body of the microscope.
The eyepiece is next put into the other end.
The arm supporting the body of the micro-
scope is then moved on one side, the eyepiece
looked through in the usual manner, until
the field is seen to be divided into two parts,
a dark and a luminous half ; the degree
which the pointed end of the arm coincides
with is then noted, and the arm is moved in
the other direction until the division of the
field is again seen ; the number of degrees
included in the arc thus traversed measures
the angle of aperture.

This is the old method (Lister's), and that
by which object-glasses are still geneially
measured ; so that, for the purposes of
comparison, it will be found useful.

But it is considered that it gives an
erroneous excess of aperture, from the ad-
mission of rays from lateral pencils, which
should be excluded. Wenhani recommends
as a more accurate method, that half the
front lens of the. object-g'lass be covered
with a piece of tin-foil. The degrees from
the half lens are then subtracted from those
of the entire lens, and twice the diflereuce
represents the aperture.

A very rough method of determining
whether an object-glass has a small or large
angle of aperture is this : direct the object-
glass, with the lower end towards the eye,
to the sky at a window ; then, keeping the
object-glass fixed, move the eye on one side
until light is no longer visible in the glass.
The extent to which the eye can be moved
round, before the light vanishes, indicates
the extent of aperture.

Another method is described in Car-
penter's 'Microscope,' 1868, p. 172, or Ro-
bin, 'Microscope,' 1877, p. 103: also Abbe's
" Apertometer," with figs., in the Jn. 3Iicr.
Soc. 1878, i. p. 19 ; and H. Smith's "Univer-
sal Apertometer," in the Jn. Micr. Sue. ii.
1879, p. 775 (fig.).

According to Abbe (Crisp), tlie aperture
of an optical instrument indicates a greater
or less capacity for receiving rays from

I

ANGULAR ArEPtTURE.

[ 45 ]

ANGULAR APERTURE.

tho object, and transmitting- them to the
iniag'e.

In the microscopic object-glass, the an-
gular apei'tuie is determined by the ratio
between its focal length and the diameter
of the emergent pencil at the plane of its
emergence from the back lens of the com-
bination.

This ratio is expressed for all media and
all cases by n sine u ; n being the refractive
index of the medium, and u the semi-angle
of aperture. The values of n sine ti, for any
particular cases, are the numerical apertures
of the object-glasses, so that in dry object-
glasses ?( = 1 ; iu water-immersion, n = r33 ;
and in homogeneous immersion object-
glasses, w = l-52.

F. Crisp gives a Table of the relation of
the ordiuar}^ expression of the angular
aperture to the numerical {Jn. Mic. Soc,
1881, i. p. 325). Thus :

180° apertiu'e = l° num. apert. ;
98° = 0°-76; G0° = 0°-50 &c. The
corresponding immersiou-apertm-es are also
given in this Table.

As an object-glass of large aperture ad-
mits a greater number of oblique rays than
one of less apertm-e, the central rays being
in nowise interfered with, so the total num-
ber of rays admitted is greater, and objects
will thereby be more brilliantly illuminated.
This is one of the advantages gained by the
use of an object-glass of large aperture ; and
the explanation applies especially to its use
in the examination of opaque objects, in re-
gard to which it can be readily understood
that a greater number of the rays reflected
from all parts of an object being admitted,
will render it more luminous and distinct.
In this case the same effect would be pro-
duced by condensing an additional amoimt
of light upon the object.

There is, however, another far more im-
portant use of large angular aperture in an
object-glass. It was first foimd by Goring
that the longitudinal and transverse lines
upon the scales of Lepidopterous and other
insects could be seen under certain object-
glasses, but not under others ; and that the
power of displaying these, or the penetrating
power of the object-glass, as it was called,
depended upon the magnitude of the an-
gular aperture. The same has since been
found the case with the markings upon the
valves of the Diatomaceoe, thus :

1 . If the valve of a Pleurosignxi angulatmn
be examined under an object-glass of 1-4
or 1-8 of an inch focus, and an angular

aperture of 60° or 70°, as illuminated by

the ordinary light of the mirror, nothing
more is seen than the more or less coloured
valve with a distinct outline, the central
line and the nodules ; and no change is
produced in the appearances, however in-
tensely the object may be illuminated. But
if an object-glass of larger angular aperture
be used, a number of fine dark parallel lines
are seen traversiug the valve. Hence the
object-glass of larger aperture possesses a
particular power of rendering indications of
structure evident, which is not possessed by
the one of less aperture.

2. If, in the same experiment, the mirror
be brought towards one side of the stage,
and the light be then thrown upon the ob-
ject, the Hues will become more distinct if
previously' visible, and frequently visible
when not so before.

3. Placing a stop in the condensing lenses
of the achromatic condenser or object-glass
will increase the distinctness with which the
markings are seen, if already visible, and wiU
frequently render them visible when not so
before.

These experiments show, that using an
object-glass of large aperture in the exami-
nation of an object, bringing the mirror to
one side, and placing a central stop in the
object-glass or the condenser, or in both,
produce the same effects, viz. that of render-
ing the markings upon an object visible
when not so previously, or of rendering*
them more distinct if previously visible.
And it is evident that the alterations of the
conditions imder which the object is exa-
mined in the above experiments, involve
simply the viewing of the object when illu-
minated entirely or more completely by ob-
lique light. For an object-glass of large
aperture admits more oblique rays than one
of less aperture, the central raj^s being in
nowise interfered with ; inclining the mir-
ror to one side, causes all the rays which
are reflected from it to become oblique ;
and the use of central stops excludes all
the central rays, so that only the oblique
rays are admitted. Hence the visibility or
greater distinctness of the markings upon
an object depends upon its illumination by
oblique light.

Experiment also shows that the degree of
obliquity of the light requisite varies with
the delicacy or fineness of the markings,
being greater as these are more delicate ; so
that the most delicate markings require the
most oblique light which can possibly be

ANGULAR APERTURE.

[ 46 ] ANGULAR APERTURE.

obtained, to render them evident, and the
angnlar aperture of the object-giass must ne-
cessarily be proportionately large, otherwise
none of these oblique rays could enter it.

In attempting to explain these pheno-
mena, we may take the opportimity of exa-
mining somewhat minutely the reason why
objects become visible to us under various
circumstances.

The ordinary cause of objects becoming
visible to us under the microscope, is tbata
certain mmiber of the rays of light trans-
mitted through or incident upon them or
their parts, either become absorbed, re-
fracted or reflected. Plence the parts at
which refraction or absorption occurs may
become either coloured or dark, whilst those
which transmit or reflect the light become
luminous. We shall leave the cases of ab-
sorption and reflection out of the question
at present, and consider only those of re-
fraction.

If the parts which refract the light are
large in proportion to the power of the ob-
ject-glass, and of irregular form, they will
refract a certain number of rays, so that
these cannot enter the object-glass, and
they will hence become dark, and will sha-
dow out, as it were, in the image formed of
the object, the structural peculiarities of the
object. But if the parts are minute, of a
curved form and approximatively symme-
trical, their lenticular foci will produce a
luminous or dark appearance, according to
the relation of the foci to that of the object-
glass. Thus, the parts of an object may ap-
pear dark and defined, from the refraction of
the light from the held of the microscope ;
also, iVom the concentration or dispersion of
portions of the light by these parts, all the
rays being admitted by the object-glass, or
entering the field.

Another condition, rather physiological
than optical, is concerned in tlie question
of the distinctness with which an otiject is
seen, nay, even of its absolute invisibility. It
consists in tlie relati(m which the luminous-
ness or darkness of an object bears to that
of the field or background upon wliicli it is
apparently situated ; and all objects, even
those seen with the naked eye, may be re-
garded as viewed upon a background or
field, comparably to an object viewed in tlie
field of the microscope. The familiar in-
stance of the visibility of the stars by day
from the bottom of a coal-pit, whilst invi-
sible from the surface of the earth, may
servo to illustrate this point. The same

phenomenon is constantly met with in
microscopic investigations ; thus it is well
known that parts of structure which are
visible most cleai'ly bv the light of a lamp in
a dark room, cannot fee distinguished when
the room is illuminated by ordinary day-
light ; and luminous objects are best seen
on a black ground, and dark objects on a
light ground.

The refraction of the light out of the field
of the microscope or beyond the angle of
aperture of the object-glass, is the ordinary
cause of the outlines of objects becoming
visible ; and in these cases an increase of the
angular aperture of the object-glass will im-
pair their distinctness, because it will allow
of the admission of those rays which would
otherwise have been refracted from the field,
and tlie margins will become more luminous
and less contrasted with the luminous field.
All that is required here is that the object-
glass shall be achromatic, and that the mar-
ginal rays shall not be decomposed, so that
any of the coloured rays should enter the
field ; in which case, the margins of the ob-
jects would appear colom-ed instead of black,
and thus the contrast requisite for distinct-
ness would be lost.

But in certain objects, the irregularities
of structm-e are of such extreme minute-
ness, or the difi'erence of the refractive
power of tlie various portions of the struc-
ture is so slight, that the course of the rays
is but little altered by passing through
them; and under ordinary illumination,
all the rays will enter the object-glass ;
neither are the lenticular foci sufticient to
map out the little light or dark spots in the
field of the microscope according to their
relation to that of the object-glass.

Let us take the instance of an object with
minute markings on the
surface, as the valve of a
Pleurosifpna. These are
so minute, that when the
light reflected from the
ordinary mirror is used,
the rays passing through
the depressed and the un-
depressed portions are not
siiliiciently refracted to
cause either set to be ex-
cluded from the ol)ji'ct-
glass, consequently both
sets will enter it (fig. li)).
But on transmitting ob-
lique light througli the
object, as represented in fig. 20, one set of

I

Fig. 19.

f=^

ANGULAR APERTURE.

[ i7 ]

ANGULAR APERTURE.

the rays will be refracted so as not to enter
the ohject-g-lass, whilst the other set will
pain admifisiou ; thus the two parts, Avhich
have dilFereutly refracted the rays, will be-
come distinct. If the markings were more

Fig. 20.

^^

delicate, or the diflerence between the re-
ii'active power of the two portions of the
valve were less than that represented in
fig. 20, both sets woidd enter the object-
glass. But on rendering the light still more
oblique, one set would be again excluded,
from being refracted out of the field. Hence
it is evident why the angular aperture of
the object-glass must be larger, as the
markings are finer, or the difference between
the refractive power of the two portions of
tissue is less ; because the obliquity of the
light requisite to cause the exclusion of one
set of the rays will be very great, and the
other set will be too oblique to enter the
object-glass, unless it be of correspondingly
large aperture.

In this way, we were wont to account for
the action of large angles of aperture and
oblique light in rendering visible the finer
markings of objects.

But the entirely new researches of Pro-
fessor Abbe of Jena, confirmed by others,
especially Crisp, Stephenson, andNiigeliand
Schwendener, have entii'ely altered the
views upon this subject.

According to Abbe's experiments and
mathematical demonstrations, the resolution
of the more minute structural peculiarities
of objects— those of less size than 5^00^ of
an inch — is produced by the superposition
of two images, one of which principally
contains the outlines of the object, and is
produced according to the ordinary laws of
dioptrics; while the other, which yields
the finer structural details, arises from the
difiraclion (or an equivalent deflection pro-

duced by refraction or reflection) of the rays
within the object, and their interference at
the upper focal plane of the object-glass,
where they produce distinct interference-
imao'es. Unless at least one of the ditlrac-
ted beams is admitted by the object-glass,
together with either another beam or the
direct incident pencil, no indication of struc-
ture is visible in the microscopical image.
And the angle of aperture of an object-glass
represents a specific property, entirely dis-
tin.ct from the magnifying and other pro-
perties of the object-glass.

If the interference-images are stopped off,
or if the angular aperture of the object-glass
is too small, the corresponding details dis-
appear entirely from the microscopic images.

xVbbe holds also, that structures of this
minute kind which an object-glass with
direct illumination does not render visible,
are also not visible when the object is in-
clined at any angle whatever to the axis of
the microscope ; even when, while lying
perpendicularly to its axis, they are perfectly
resolved by oblique light.

An important residt of these views is,
that minute structural details are not, as a
rule, imaged by the microscope dioptiically,
in accordance with the real nature of the ob-
ject, and cannot be interpreted as morpho-
logical but only as physical characters : not
as images of material "forms, but as signs of
material differences in the nature of the
particles composing the object, so that no-
thing more can safely be inferred from the
image aspi'esentedto the eyethan the presence
in the object of such structural peculiarities
as will produce the particular difli-action-
phenomena on which the images depend
(Abbe).

In regard to the action of oblique light
and angular aperture in rel.iUou to colour:
neither oblique light nor largo angular aper-
ture possesses any power of rendering co-
loured transparent objects more distinct;
and markings, when arising from the pre-
sence of pigment, are perfectly visible under
an object-glass of smnll aperture, and the
ordinary light of the mirror.

When objects are examined under im-
mersion-lenses, they appear more brilliantly
illuminated, especially in regard to the finer
details. This is partly to be attributed to
the diminution of the loss of light from re-
flection at the surfaces of the cover and the
under surface of the object-glass; but mainly
to tlie circumstance that a larger number
of oblique rays are enabled to enter the

ANGULAR APERTURE. [ 48 ]

ANLMAL KINGDOM.

object-glass, from the higher refractive
power of the immersiou-liquid, which pro-
duces the effect of an increased angle of
aperture in the object-glass. This admis-
sion of an increased number of oblique rays,
would tend to invalidate the view, that the
more delicate structures are rendered visible
by the removal from the field of certain
oblique rays ; but it would favour the
rendering of the markings visible by their
lenticular foci. According to the diffrac-
tion-theory, the admission of a larger num-
ber of diffraction-results would explain the
increased distinctness resulting from the
immersion-arrangements.

Many rather controversial articles on the
relation of the dry- to the immersion-aper-
tures will be found in the M. M. Jn, from
1872 to 1877.

It was noticed by Goring, that although
the lines on the scales of certain msects re-
quired an object-glass of comparatively
large aperture to show them, yet those ex-
isting upon glass micrometers did not so.
But this statement is only partially correct ;
for although the coarser lines upon micro-
meters are well seen under an object-glass
of small aperture with good defining power
and direct light, yet the finest lines upon
Nobert's test-slide require penetrating power
in the object-glass, and oblique light. Thus,
R. Beck found that a -ith-in. object-glass of
120° would show all the 20 sets of Nobert's
lines; when cut down to 110°, it woidd not
resolve the 20th band ; at 100° the 17th
was the limit ; at 80° the 14th ; and at 60°
the 10th.

Our space vrill not permit of entering into
further details on this important matter ;
but we shall refer to it again, in its relation
to the markings on the L)iatomace^.

Aperfxres of Objed-ylasses. — The follow-
ing apertures of (dry) object-glasses may be
taken to represent those usually niet with
in good glasses : 2", 14° ; 1", 25 ; f ", 32° ;
i",40°-80'-^; i", 75°-140°; ^",140°; -fV,
i4rj°-170°; 5!^", 160'^;_ and ^V"» l-'50°. The
apertures of the foreign object-glasses ai*e
usually over-estimated by the malcers in
their price-lists.

The transverse lines seen upon the scales
of insects are noticed under Scales of In-
sects. The structure of the valves of the
Diatom ACE.^ is discussed imder that head ;
see also Introduction, p. xxxix, /.

BiBL. Lister, Phil. Tr. cxxi. ; Goring,
Mkrogrnphia ; Pritchard, Micr. Ccthinef ;
R. Beck, Treatise ^-c. 19 ; Weuhani, M.

M. J. 1872, viii. 231 & 1876, xvi. 285 ;
id. Jn. Mic. 80c. 1878, i. 321; Abbe
(abridged by Fripp), M. M. Jn. 1875, xiv,
191, 245; id. {Theor. d. Mik.) Arch. f. mik.
An. 1873, ix. 420; (estimation of aperture)
Jn. Mic. Soc. 1881, i. 388; Apertometer
(figs.), Jn. Mic. Soc. 1880, iii. 20; Helm-
holtz (Theor. Grenze f. d. Leist.), Poyyen-
dorff's Ann., Jubelband, 1874, p. 566 ; "Ste-
phenson, M. M. Jn. xiv. 3 & xvii.82; Nageli
andSchwendener, Mikr. 1877, p. 82; Stokes,
Jn. 3Iic. Soc. 1878, i. 139; F. Crisp,
Jn. Mic. Soc. 1881, i. p. 303 (full description
and illustrations of Abbe's views) ; Wenham,
Amer. Jn. Micros. 1881.

ANIMALCULE. — A little animal ; a
term usually applied to the Infusoria, Ro-
tatoria, &c. It was formerly applied also
to many of the lower Algfe. The Latin
term animcdcidi(m (plural animalcula) is
frequently met with.

ANIMAL KINGDOM.— In accordance
with our plan, as laid down in the Preface,
we give here a tabular view of the animal
kingdom, so that the position of the various
classes and orders alluded to in various parts
of this work may be readily found. Those
classes, orders, families, and genera to which
particular interest is attached in relation to
structure or other qualities, which the micro-
scope is required to investigate, are specially
treated of mider their respective heads.

Kmgdom ANIMA'LIA.

Subldugdom I. Vebtebha'ta.

Class I. Mamma'lia.

Order 1. Bi'riana.

Homo, man.
Order 2. Quadru'mana.

Simia, ape ; Cercopithecvs, common
monkey; Semnojnthecus^Yin^iAW mon-
key.
Order 3. Cheirop'teka.

VespertiUo, bat.
Order 4. Insecti'vora.

Erinaceus, hedgehog ; Talpa, mole.
Order 5. Oaiini'vora.

Cams, dog and wolf; TTrsns, bear;

Felis, lion ; Aasua, coatimondi.
PiNNiPEDiA. Phoca, seal.
Order 6. Ceta'cea.

Balatna, whale ; Phoccena, porpoise.
SiRENiA. ^rt/jcore, dugong ; Manatus,
manatee.
Order 7. PAcnYDER'MATAf.

Equus, horse; Sus, hog; Hippopota-
mus ; Choir opotamus.
I

ANIMAL KINGDOM.

[ 49 ]

ANIMAL KINGDOM.

PnoBOSciDEA. Elephas, elephant.
Order 8. Iiuminan'tia f-

Bos, ox; C'<rwi(V«*", camel ; Ci?n?MS, deer ;
Cupi-a, goat ; Oris, sheep.
Order 9. Edenta'ta (Bruta).

Dasj/jms, aruunliUo ; Bradijpus, f^loth.
Order 10. Koden'tia.

Cavia, guiuea-pig ; Lepus, hare ; Mus,
mouse and rat ; Sciurus, squirrel ;
Cdsfor, beaver and musquash ;
Chinchilla.
Order 11. Maksupia'lia,

Macrojms, kangaroo; Didelphys, opos-
sum.
Order 12. Moxotkem'ata.

Ornithorhyndtus, duck-Lillod platjquis.

tt These two orders form the Class Uugu-
lata of some authors.

Class II. AvES, Hrds.

a. Carixatje.
Order 1. Eapto'kes; birds of prey.

Aquila, eagle ; Strix, owl.
Order 2. Insesso'ees (Passeres) ; per-
chers.

Frinf/iUa, finch ; Hirundo, swallow ;
Turdus, thru.sh, blackbird.
Order 3. Scanso'kes ; climbers.

Cuculus, cuckoo ; Psitiacus, parrot.
Order 4. Galli'n.t. ; IIaso'kes.

Galhis, fowl ; Columba, pigeon.
Order 5. Grallato'rks ; waders.

Gi^us, crane.
Order 6. Natato'res ; swimmers.

Larus, gull; Anas, duck; Anser,
goose.

h. Ratit^.
Order 7. Cueso'res ; rmmers.

Siruthio, ostrich.

Class m. Reptilia, reptiles.

Order 1. Chelo'nia.

Tesfudo, tortoise.
Order 2. Sau'ria.

Lacerta, Uzard.
Order 3. Ophid'ia.

Boa ; Coluber, snake.
Order 4. Crocodil'ia.

Crocodilus, crocodile.

Class IV. Amphibia.
Order 1. Axlt'ra.

Bana, frog ; Biifv, toad.
Order 2. Urode'la.

Jy-iVon, water-lizard ; Menopoma; Pro-
teus.

Class V. Pisces, fishes.

Order 1. Ganoi'dea,

Lepidosfeus, bony pike; SfMrio, stur-
geon.
Order 2. Placoi'dea.

Carcharias, sliark ; Baia, skate.
Order 3. Ctexoi'bea.

Perca, perch.
Order 4. Cycloi'dea.

Salmo, salmon; Cliipea, herring; Cy-
prinus, carp.
Order 5. Cyclos'tomi.

Petromyzon, lamprey.
Order 6. Leptocar'dea,

Amph ioxus, lancelet.

Subkingdom II. Mollusc A.

Class I. Cephalop'oda.

Sepia, cuttle-fish ; Nautilus.
Class II. Gasterop'oda.

Helix, snail; Limax, slug; Littorina,
periwinkle.
Class III. Pterop'oda.

Clio.
Class IV. Conchie'era (Lamellibran-
chia'ta), shell-iioh.

Ostrea, oyster ; Mytilus, mussel.
Class V. Brachiop'oda.

Terehratula, lamp-sliell.
Class VI. Tunica'ta.

Ascidia, Salpa, BofryllHs,A>}iarouciuni.
Class VII. Polyzo'a (Bryozoa), Sea-
mats, &c.

Subkingdom III. Arthrop'oda (Arli-
culata).

Class I. Crustacea, crabs, lobster, &c.
Order 1. Decap'oda.

Cancer, crab ; Astacus, lobster and cray-
fish.
Order 2. Stomap'oda.

Squill a.
Order 3. Amphip'oda.

&'«?«y?2«/-M5, freshwater shrimp.
Order 4. Isop'oda.

Oniscus, wood-louse ; Asellus, water
wood-louse ; Limnoria.
Order 6. Phyllop'oda.

Branchipus, Ariemiu.
Order (3. Cladoc'era.

Daphna, water-fieas.
Order 7. Copep'oda.

Cyclo})s.
Ordt r 8. Ostraco'da,

Cypris.

O
g

o

GO

)rt-
•-<
?3
Q
SO

E

ANIMAL KINGDOM.

[ 50 ]

ANIMAL KINGDOM.

Ordor 0. Cirmpk'dta {Cirrhopoda).

Balanus, acorn-.shell ; Lepas^ barnacle.
Order 10. Sii'Honos'toma {JcMhi/o-

phthira) ; fish-lice.
Order 11. Pcecilop'oda.

Limulus, king-crab.

Class II. Abachni'da, spiders.

Order 1. Arane'ida.

Aranea, house-spider ; Epeira, garden-
spider.
Order 2. Pedipal'pi.

Scorpio, scorpion.
Order 3. .Solif'uga.

Galeodes.
Order 4. Pseudoscoepio'nes.

Chdifer.
Order o. Phalan'gida.

Phalnmjium, harvest-spinner.
Order 6. Acari'na.

Acdfus, mites.
Order 7. H XRT>i(i'B,XT>x{Colopoda); water-
bears.
Order 8. Pycnogon'ida {Polygonopoda).

Pycnoyonuni,

Class III. Myriap'oda.

Order 1. Chilogna'tha.

lulus.
Order 2. Chilop'oda.

Lithohius.

Class IV. IxsECTA, insects.

Order 1. Coleop'tera.

Beetles.
Order 2. Orthop'tera.

Blatta, cockroach ; Acheta, cricket.
Order o. IIemip'tera.

Cimex, bug ; Aj)his ; Aphrojyhora, cuc-
koo-spit.
Order 4. Neurop'tera,

Ephemera ; Lihellula, dragon-fly.
Order 5. Lepidop'tera.
Butterflies and moths.
Order G. Hymenop'tera.

^^«s, bee; J>S7>«, wasp; Formica, oxit.
Order 7. Dip'tera.

Oestrus, bot-fly ; Musca, house-fly.
Order 8. Strepsip'tera, bee-parasites.

Sti/lops.
Order 9. Aphanip'tera {Siphonaptera ;
Sucioria).
Pule.v, flea.
Order 10. Anoplu'ba.

Pediculus, louse.
Order 11. Tiiysanu'ra.
Lepisma, Podura.

Subkingdom IV. Vermes.

Class I. Anxula'ta {AneUida).

Order 1. Setig'era.

Lumhri'cus, earthworm; Nais) Ta'hi-
fe.v ; Aphrodi'ta.
Order 2. Sucto'ria.

Hirudo, leech.
Order 3. Turbella'ria.

Planaria.

Class II. PtOTATORiA (Potiferu).

Class in. Entozo'a.

Order 1. Cestoi'dea, Tape-worms.
Tcenia ; Bothrioeephalus, Acanthocepha-
lus (Ct/stico, Ci/sticercus, Echinococ-
cus, Ca'tiurus).
Order 2. Tremato'da.

I)is'fo)na,iinke, (Cercwia); Gijrodac-
li/liis.
Order" 3. Acanthoceph'ala.

Echinorhi/nchus.
Order 4. Nematoid'ea.

Tricocephalus, Filaria, Ascaris (Oxy-
uris), Anyuillula, Gvrdius, Trichina.

piADIATA.

Subkingdom V. Echixoder'mata.

Class I. A'poDA.

Chirodota.
Class II. Pebicella'ta.

Aster ias, star-fish ; Echinus, sea hedge-
hog ; Ophiocoma ; Spatanyus.

Subkingdom VI. Ccelentera'ta {Zvo-
2)hytes).

Class I. Actinozo'a (Anthozoa, Polypi).
Order 1. Zoantha'ria.

Actinia, sea-anemone ; Sayartia; Mud-
rejjora, stone-coral.
Order 2. Alcyona'eia.

Akyonium, Goryonia, sea-fan.

Class II. IlYDROiiEDTj's^ (Ilydrozo'a).

Order 1. Discoph'ora (Acakphcs).

Medu'sa, sea-nettle, jelly-fish ; Cyancca.
Order 2. IIydroi'da.

Hydra; Sertularia; C'a7npanularia.
Order 3. Siphonoph'oba.

Physalia, Portuguese man-of-war.

Class III. Ctenoph'ora.

Beroe.

ANIMAL KINGDOM.

L 51 ]

ANNUAL RINGS.

Subkingdom VII. Pbotozo'a.
Class I. Infcsob'ia.

Class II. Rhizop'oda.
Order 1. Reticula'ria.
Gromia, Foramiuifera.
Order 2. Radiola'ria.

Ac/inop/iri/s, Acanthonietra ] Po/i/ci/s-
tina.
Order 3. Lobo'sa.
Amahtt, ArceUa.
Order 4. Ctregari'nida.

Class III. Spongida.

MONEEA.

BiBL. Rvmer Jones, ^n. Kitifjd.; Todd's
Ctfd. ofAnaf. ; Siebold and Staniiius, Lehrb.
d. rergl. Anaf. ; D'Orbigny, Did. cVHist.
Kat. ; V. d. lloeveu, Ilundb. d. Zool. ; Owen,
Hunt. Led. ; Carpenter, Compar. Physiol. ;
CuAier's An. Kiwjd., by Blyth, Mudie,
JohriStoii, Carpenter, and Westwood; Vogt,
Zool. Briefe ; Gosse, Mar. Zool. ; Caru?, Ic.
Zvof. {Inverfehrata) ; Blancbard, licyne
Animal ; Leydig, Lehr. d. Hist. ; Baird,
Nat. Hist., 1863; Green, Cfefew/era^'ff, 18G3;
Van Beneden, Anat. Cvmp. ; Strieker, Geiv.
d. Mensch. u. Thieve, 1872 ; Hackel, Gen.
Morph. ; Cheuu, Bncyd. d'Hist. Nat. (8000
%s.), 18(36; Thome, Zool, 1875; Hayek,
ZooL, 1877 ; 'Uxown, Die Klass.d. ThierreicJis,
1880; Clans, Grundziuje d. Zool, 187o ;
Schmidt, Handb. d. veryl Anat., 1876 ;
Sc'hmarda, Z)ol, 1878 ; Nicholson, Man.
ZjoI, 1878; Gegenbanr, VerylAnat., 1878 ;
HiLxley, Liv. Sc Vert., 1872 ; R. Lankester,
Qu. M. Jn. 1877, xvii. p. 399 ; Pascoe, Zool.
Class., 1880 ; M' Alpine, Zool., 1881.

ANISONE'MA, Duj.— A genus of Infu-
soria, belonging to the family Thecamona-
dina (Flageliata, Kent).

Char. Body colourless, oblong, move or
less depressed, covered 'wdth a resisting
tegument, from an aperture in which t^wo
filaments emanate — one flagelliform and
directed forwards; the other thicker, trail-
ing and retracting the body of the animal ;
movement slow. 2 species : —

A. acinus ((jrunde). Movement directly
forwards, colourless; length 1-1280 to
1-810" ; fr. wat. among Confervce.

A. sulcata (PI. 23. f. 12). Movement
vacillating in a circle; colourless; fr. wat.;
length I-llOO".

3 other species. Piijardin suggests that
the Bodo grandis of Ehrenberg is refeiable

to one of these species, as also to the genus
Hefrroiiiifa, Duj.

BiBL. Dujardin, I/ifns. p. 345 ; Kent, Inf.
p. 434.

ANKISTRODESMUS, Curda (liaphi-
diuin, Rabenh.). — A genus of Desmidiaceae.

Char. Cells elongated, attenuated, entire,
aggregated into faggot-hke bundles.

The ceUs only ditFer from tliose of Closte-
riuin in their aggregation. Species :—

A.falcatus, Corda {^Rhaphidium fascicu-
latum, Kiitz.). Cells numerous, crescent-
shaped : aquatic ; length 1-549", breadth
1-7353" ; common. (PL 14. fig. 47.)

A. fimformis, Corda. I /-i i i i
A • 1 t r\ ^ ) Carlsbad.

A. convolutus, Corda. |

BiBL. Ralfs, Brit. Desmidieee, pp. 179
and 222 ; Corda, Alman. d. Carlsbad, 1835,
p. 121, 1838, p. 199.

ANNUAL RINGS. — The concentric
lines seen in transverse sections of Dicoty-

Fiff. 21.

Cross section of a Dicotyledonous stem with annual
rings.

ledonous stems (tig. 21) generally indicate
successive annual additions to the woody
structure; and in these cases depend on the

Fig. 22.

Magnified croai section of stem of Finns, exhibiting
parts of three annual rings, 1, 2, 3.

difference of the character or condition of
the tissues produced at difl'erent seasons.

e2

ANNUL ATA.

[ 52 ]

ANNUL AT A.

Ordinarily there are a number of ducts
grouped near the inner part of each con-
centric layer of wood, as in the Oak. In
the Sumach a layer of cellular tissue occurs
at the boundary of each ring. Li the Coni-
fers, the markings result from the greater
thickness of the secondary deposits on the
walls of the cells in the outer part of each
layer, no ducts existing in their wood (fig.

It seems that these rings cannot be taken
strictly as annual rings in all trees, especially
in those of equable climate, since they
appear to depend upon external influences
affecting the activity of vegetation ; and
thus, even in temperate climates, a great
loss of foUage in the summer, followed by
recovery, may produce two rings in one year.
In moist tropical climates, where the leaves
reappear almost continuously, the rings pro-
babij' answer to j^eriods of great renewal of
foliage.

ANNULA'TA, Anellida.— The class of
red-blooded worms, &c.

Char. Elongated animals, living in water
or moist earth, not par asitically within other
animals ; body usually ringed or jointed ;
feet not jointed, and frequently replaced by
bristles or retractile setigerous tubercles,
llespiration eflected either by external
branchiie or by internal vesicles, or by the
skin itself. Distinct organs of circulation
present, contractile vessels replacing a
heart. Nervous system consisting of a
single or double ventral cord, furnished
with ganglia at intervals, and eueircUng
the oesophagus above.

The skin consists of a very delicate struc-
tureless and transparent epidermis, beneath
which (in Il(S7)toch(iris (I'iscicola), Clepsine,
and Kep/ic/is) there is a layer of cells, Avhich,
in the adult animals, presents the appearance
of a fenestrated membrane (PL 49. fig. 16).
The cells (PL 49. iig. 166) leave spaces
between them which appear like holes ;
but the addition of acetic acid brings to
light in each space a distinct nucleus (PL 49.
fig. 16 c), and in very young animals the
clear spaces are distinct cells, distinguish-
able from the surrounding cells by their size
and containing numerous clear vesicles as
well as a nucleus. The smaller cells contain
a nucleus and numerous nuclear granides.
Beneath this cellular layer are numerous
large fat-cells, pigment-cells, and connective
tissue, the latter consisting of a transparent,
homogeneous, semisolid mass. A layer of
line but firm fibres, crossing each obliquely,

is said to be sometimes met with beneath
the epidermis and forming a corium or true
skin.

In the Turbellaria, the outermost cuta-
neous layer consists of ciliated epithelium.
The opalescentand often beautiful!}' coloured
skin of many of the Annulata does not gene-
rally owe its tints to distinct pigment, but
to iridescence produced by the fibres.

The rings of the body are usually furnished
with bristles or hairs, sometimes arranged in
tufts, at others covering the greater part of
the surface of the body.

The bristles are most exquisite objects
for microscopic observation, displaying the
greatest variety of form, constituting lances,
spears, knives, saws, sickles, hooks, &c., of
innumerable elegant shapes, often curiously
jointed, and usually fashioned out of an
elastic material that rivals the clearest glass
(Gosse). Sometimes fuliaceous appendages
cover the body Uke. scales. Most of the
Annulata are covered with a kind of mucus,
secreted by the cutaneous glands ; some
live in leathery tubes or sheaths ; in others
a case is made by the consolidation of the
secretion from some part of the skin with
fragments of shells, grains of sand, &c. ; in
others, again, the calcareous tubes appear
to be whoUy secreted by a portion of the
cutaneous surface.

The muscular sj/stetn is usually well de-
veloped. The muscular fibres are in some
arranged in three layers, an outer consisting
of annular, an inner of longitudinal, and an
intermediate of oblique fibres ; in others
there is an outer layer of oblique fibres, an
inner of longitudinal, with annular fibres at
the two ends of the body. The muscular
fibres consist of cylinders, the transverse
section of which is rounded (PL 49. fig. 17a),
flattened or incurvated (PL 49. fig. 17 i).
They are covered externally by a delicate
sheath or sarcolemma (PL 49. fig. 186). TJie
cylinders themselves consist of a clear, homo-
geneous, cortical substance (PL 49. fig. 18a),
and an internal cavity (c), the latter being
filled with a finely granular substance, in
which scattered nuclei are imbedded (PL 49.
fig. 17 c). At the two ends of the body,
the muscular fibres branch dichotomously
(PL 49. fig. 19c). The fibres are usually
smooth, but sometimes longitudinally or
transversely striated ; this appearance arising
either from folds in thesarcolemma or proper
sheath, or from the granules being arranged
in linear series.

In the Turbellaria, phe muscular system

ANNULATA.

[ •'53 ]

ANNULATA.

is but slightly developed, the tissue beneath
the slriii consisting of globuUir masses re-
sembling the general parenchyma of the
body ; and in this, peculiar cellular bodies
are often imbedded, resembling the urti-
cating organs of the polypes. These enclose
six, eight, or more rod-shaped bodies,
which are sometimes parallel with each
other, sometimes somewhat spirally curved.
The cell-membrane of these bodies subse-
quently disappears, and they frequently
project beyond the skin. Ley4ig figures
similar rod-shaped bodies as occurring in
the nuclei of the fat-cells situated beneath
the skin.

In many of the Annulata, the muscular
fibres are grouped into distinct bundles,
serving to move the bristles, parts of the
mouth, Sec.

Beneath the skin at the ends of, or all
over the body, a number of peculiar glands
exist ; these consist at the closed end of a
nucleated cell (PL 49. fig. 19^*0^), and a
long, somewhat coiled duct opening at the
surface of the body.

The nervous system consists of a longi-
tudinal, single or double series of ventral
ganglia, connected by longitudinal cords ;
the uppermost ganglion lies above the oeso-
phagus, and the two cords which connect it
with the second ganglion encircle this organ.
The uppermost ganglion is enveloped in
a neurilemma consisting of longitudinal
and transverse fibres, and not unfrequently
peculiar pigment-cells. The cords and
filaments are composed of extremely deli-
cate primitive fibres, between which, in
the ganglia, ganglion-globules are situated.
The filaments distributed to the body arise
piincipally from the ganglia.

Many of the Annulata are furnished with
eyes ; these are usually denoted by the
brown, black, or red spots seen upon various
parts of the body. It is a disputed point
whether all these represent true eyes or
not ; but Quatrefages has described a lens,
transparent cornea and vitreous humour in
some of them, and he has no doubt tliat the
red points found at the sides of each ring in
several species of Nais are true eyes.

In some Annulata, no distinct head is
present ; in others this is distinguishable by
its form, and is furnished with eyes and one
or more filaments, which are regarded as
antennae. In those in which the head is not
distinct,the mouth is situated at the anterior
end of the body ; in the others the mouth is
on the ventral surface, and is furnished with

a muscular proboscis. The mouth is usually
surrounded by turgid lips, and sometimes
possesses a distinct dental armature (see
IIiRUDo). The oral aperture is frequently
surrounded by a number of erectile tentacles
or cirri.

The intestinal canal is usually straight,
and furnished with lateral appendages, or
constricted at intervals ; sometimes a sepa-
rate oesophagus, stomach and intestine are
di.-tinguishable. The inner, and sometimes
the outer surface of the alimentary tube is
covered with ciliated epithelium. A yellow
or brown glandular layer surrounding the
alimentary canal represents the liver.

The general arrangement of the cir-
culatory system is, that two main vascular
trunks, one dorsal, the other ventral, tra-
verse the body longitudinally ; and the red
or green blood moves in the dorsal vessel
from behind forwards, whilst in the abdo-
minal vessel it moves from before back-
wards; these trunks being connected by
transverse vessels or meshes of them. The
anterior portion of the dorsal vessel is
usually broader, and appears to form the
rudiments of a heart.

The respiration of the Annulata is effected
either by the skin ; by external gills in the
form of tentacidar filaments or tufts, some-
times ciliated ; by ciliated depressions, or
by vesicles at the sides of the body. The
internal convolute ciliated canals, or water-
vessels, which were formerly considered
respiratory organs, are now regarded as
secretory tubes. In many instances a
transparent colourless liquid occupies the
interstices between the skin and the organs
of the body ; this contains colourless (rarely
coloured) corpuscles much resembling the
colourless corpuscles of the Vertebrata, and
is considered by some to represent the true
blood.

The Annulata are propagated by trans-
verse division, by gemmation, and by means
of sexual organs. The embryos are at first
minute, rounded, and partially covered with
vibratile cilia.

Order 1. Ch^topoda (Setigera). Body
ringed, elongate, with feet or setigerous
rudiments of them ; external branchiae
usually present.

Order 2. SrcxoniA (Apoda). Body
elongate, ringed, without bristles or foot-
like tubercles ; locomotion by sucking-disks ;
no external branchiaB.

Order 3. Tuebellaeia. Body bilateral,
soft, covered with vibratile cilia, not seg-

ANODUS.

[ 54 ]

ANOPLURA.

merited ; eyes distinct ; sexless or herma-
phiodite.

BiBL. Siebold, Lehrh. d. vergl. Anat. i. ;
Jones, A71. KiiKjd. ; V. d. Hoeven, Ilundb.
d. Zool. i. ; INIilne-Edwards, Tvdd^s Cyc. of
Anat. Si-c. ; Johnston, Brit. Anell. ; Gosse,
Ma7\ Zool. i. ; Vogt, Zool. Brief e ; Claparede,
An. Chetopod. (Qu. M. Jn. 1869, p. 306) ;
id. Ann. N. H. 1867, xx. p. 337 ; Elders,
D. Borsti'mciirmer, 1869 ; Agassiz, Attn. N.
H. 1867, xix. p. 242 ; Quatrefages, Suites a
Biiffon ; Gegenl)auer, Verrjl. An. 1878 ; R.
Lankester, An. X. H. 1871 ; Art. Anellida,
Encyd. Brit. 1875, ii.; Marion, M. 31. Jn.
1875, xiv. 17 (coloured corpuscles in blood) :
Pascoe, Zool. 1880, p. 58 ; Hallev, TurleU.
1880; Wilson, An. N. H. 1880, vi. 407
(devel.).

AN'ODUS, Er. & {->b. = SELiGEi!iA.

AK(ECTAN'GIUM, Br. & Sch.=ZY-

GODON.

ANOMALI'XA, D'Orb.— Witb some ex-
ceptions (as An. eleyans, D'Orb., which is a
small Discorhi}ia^ the Anomalincs are some-
what bicunvex Trimcaiulinep, neat, dhcoidal,
and subnautili.id, witli nearly as much con-
vexity of the chambers on the lower as on
the upper side of the shell. Abundant, both
recent and fossil.

BiBL. D'Orb., Jo/-. Foss. Vicnn. p. 169;
Carpenter, For. p. 208.

ANOMALO'CEKA, Temp.— A genus of
Entomostraca, of the order Copepoda and
family Diaptomidfe.

Char. Ilead distinguishable fi-om the
body, with a bifid beak and a hooked spine
at the base on each side ; thorax with six,
abdomen with four segments; foot-jaws
three pairs ; last pair of legs diflfering from
the others ; eyes single, pedunculated in the
male; right superior antenna with a swollen
binge-joint (in the male): inferior antennse
not branched, three-jointed, basal joint with
a slender twig. 1 species: —

A. Patersonii (PI. 10, fig. 6, the male).
Mai inc.

BiBL. Templeton, Tr. Fntom. Soc. vol. ii.
1837; 15aird. Brit. EntomoMr. p. 229.

ANOM'OBON, Hook, and Taylor. See
Neckeija and IIypnvm,

A]S'()PIlUY8,Cohn.

-A genus of IIolo-

tiiclious Infusoria.

Char. Eree swimming, elongate-ovate,
pointed and curved in front, rounded
behind ; a fascicle of longer and stouter
cilia issuing from the ventral oral cleft.

A. saraphajia (PI. 53. tier. 6). In salt
water, with decaying animal matter.

BiBL. Kent, Infi/s. p. 511.
ANOPLOPH'ORA, Stein (Opalina,-pQ.
— A genus of Holotrichous Infusoria.

Cliar. Body elorgate or ovate, nucleus
band-like, axial ; contractile vesicles evi-
dent.

The (15) species are intestinal parasites
of JVais, LumhricKs, and other Invertebrata.
BiBL. Kent, Infits. p. 563 ; Stein, Inf.
AIsOPLU'KA.— An order of Insects;
sometimes termed Parasitica or Epizoa.

Char. Legs six ; wings none ; parasitic,
and not undergoing metamorphosis ; eyes
two, simple, or none.

These insects are parasitic upon mammials
and birds, and are commonly known as lice.
The order is thus subdivided : —
Subord. Haustellata (Rhyxchota).
Mouth with a tubuhu", vei-y short
Heshy haustellum.
Fam. Pediculid^e. Autennre five-
jointed.
Gen. Phthirius. Anterior legs for

walking, posterior for climbing.
Pt'dicuhis. Legs all for climbing ;

abdomen of seven segments.
Pedivinus. As Pedicuh/s, but abdomen

of nine segments.
Ha-matojnnus. Legs all for climbing ;
abdomen of eight or nine segments.
IIcc7nat(>mi/zus. Claws single.
Subord. Mandibulata (Mallophaoa).
Mouth with two hornj^ mandibles.
Fam. PniLOPTEKiDiE. Antennaj fili-
form, maxillary palpi none.
Pltiloptcrus. Antennas five-jointed ;

tarsi two-jointed, claws two.
Trichodcctes. Antenna} three-jointed ;
tarsi two-jointed, with one claw.
Fam. LioTHEiB^E. Antenna? clavate ;
maxillary palpi conspicuous.
Liothenm. Tarsi two-jointed, with two

claws.
Ci/ropus. Tarsi two-jointed, with one
claw.
It appears that alllu ugh the Anoplura do
not undoigo metamorphosis as in the more
perfect insects, consisting of larva, pupa and
imago, widely ditiering from each other in
general appearance, habits, and functions,
yet a seiies of semitransformations takes
place in the shedding of the skin a definite
niim])er of times, by which the individual
acquires a greater symmetry of foim, and
most probably a greater perfection of parts
or organs.

Bim,. Nitzsch, Germar and Zinclen^s
May. d. Entom. iii. ; Burmeister, Gen.

I

ANOUEELLA.

[ 55 1

ANTENNAEIA.

InRcct. ; Leach, Zool. Misc. iii. ; Gurlt,
Thicrhcilh. viii.; Denny, Mon. Anopl. Brit.;
id. {Cliinese), Qu. Mic. Jn. 18G4, p. 18;
Walckenaer, Hist. d. Insect, xiii. ; Landois,
Sieh. Sf- KoU. Zeits. 18C.5 {Qu. M. Jn. 1800,
p. M) ; Mtnray, Ec. Entomol. 1879, p. 375;
Mt^jmin, Parasites, 1880.

AIsOURELLA, Bory and Duj. = Anu-
EJEA, Ehr,

ANTEN'NyE, of Insects.— The two
moveable jointed organs, situated on the
head, near the eyes (PI. 33. figs. Iff, 3a,
24 a, and figs. 7 to 21 inclusiye).

The form, number of joints, &c. of the
antennas are used as characters for distin-
guishing the genera and species of Insects.

Three parts are generally recognizable in
the antennas : 1, the scapus or basal joint
(figs. 10, 18, and 19 «) is often very long,
and is connected with the torulus, or part
upon which it moves, by a ball and socket
articulation ; 2, the ^lediceUa or second joint
(the same figs., h), which is mostly minute
and nearly spherical, allowing of the freest
motion, and supporting the remaining por-
tion of the antennje, which forms, 3, the
clavola (figs. 10 and 18 c). The principal
terms applied to the antennfe according
to the form and arrangement of the joints
of the clavola are these : —

They are called setaceous when the succes-
sive joints gradually diminish in size from
the base to the apex, as in the families
Achetidoe, Blattidfe, and Gryllidae (fig. 7) ;
ensiform when the successively diminishing
joints are angular at the sides, forming a
sword-like organ, as in some of the Locust-
idse (fig. 8) ; filiform when all the joints of
the clavola are of uniform thickness, as in
the Carabidfe (fig. 9) ; moniliform when the
joints are spherical or rounded, as in the
Tenebrionidffi and Blapsidfe (fig. 10) ; ser-
r«?'«/ when the joints appear like inverted
triangles, with the inner margin more pro-
duced than the outer, as in sf)me of the
Elateridae (fig. II) ; imbricated when the
acute base of each joint is inserted into the
middle of the broad ajiex of the joint behind
it, as in the Prionidfe (fig. 12); pectinated
when each joint is developed on one side
into a process or spine, as in the Lampyridas
(fig. 13); bipectinated when a process or
spine exists on each side of the joints, as in
the Bombycidas (fig. 14) ; fiabellate when
each of the processes is flattened, and nearly
as long as the whole of the succeeding joints
taken together, as in some of the Elateridas
(fig. 15) ; clavate when the clavola ends in a

gradually formed Itnob (fig. 10), or capitate
when the knob is suddenly formed (fig. 17),
as in the Pentanierous Coleoptera; plumose
when one or more minutely pectinated
branches arises from the joints, as in some
of the Muscidae (fig. 20), or when tufts of
capillary filaments arise from the joints, as
in the Culicidas (fig. 21) ; knnellate, as in the
lamellicorn Coleoptera, when the knob is
composed of a number of lamellas or plates
(fig. 18 f/), andperfoliate when the joints of
the knob are separated slightly from each
other by a minute foot-stalk. There are
many curious variations in the structure of
the antennte ; thus, in some of the Muscidse,
the filamentous portion represents the true
clavola, while the larger lobe is simply an
appendage (fi^. 20) ; in Glvbaria Leachii
the pedicella is not a small rounded joint,
but is elongated like the scapus (fig. 19 5),
whilst the clavola (c) ends in a large capi-
tulum attached laterally to the base of the
fifth joint, and directed backwards.

The use of the antennae is that of hearing
or feeling the vibrations of the atmosphere,
and of smell. B. Hicks has pointed out the
existence in numerous insects of minute cavi-
ties or pits in the surface of the antennae,
furnished with a nerve-branch at the base,
to which these functions are attributable.
Hicks recommends the use of an aqueous
solution of chlorate of potash, acidified with
muriatic acid, for bleaching the chitine, and
rendering these organs distinguishable.

An additional function in many insects
is that of common feeling or touch.

G. Hauser describes also a terminal sen-
sory organ in the antennae, composed of
bacillar cells, connected with a largish
nerve.

BiBL. Kirby and Spence, Entomol. ; Bur-
meister's Man. SfC, transl. by Shuckard ;
Newport, Art. Insects, Todd's Ci/cl. An. Sj'c.
ii. ; Westwood's Introd. S^c. ; Hicks, Linn.
Tr. 1859, xxii. pp. 147 & 323; Claparede,
Ann.d. Sc. Nat. Zool. 1858, x. p. 230; Hauser,
Zeit. tciss. Zool. 1880, xxxiv. p. 307 (Jn. Mic.
Soc. 1881, i. p. 33).

ANTENNA'RIA, Link.— A supposed
genus of Antennariei ( Phycomycetous
Fungi), referred by Fries to Perisporiaceae,
and probably often consisting of forms of a
Mucediuous state of Capnodium. They
are byssoid products growing upon dead or
living structures, or sometimes in cellars.
A. (Eacodium) mlhiris is the fungus of wine-
cellars, and is placed by Fries in the genus
Zasmidium,

ANTENNARIEI.

[ 56 ]

ANTHER.

Fig. 22 a.

Antennaria laevigata. Highly magnifled.

BiBL. Corda, Icones, i. pi. 6. fig. 289 ;
Berkeley, Crypt. Bot. p. 275 ; Oooke, Hand'-
book, p. (WS.

ANTENNARIE'I.— A supposed family
of Phycomycetous Fungi, consistiug of dif-
fuse plants, forming tlocculent or byssoid
patches upon leaves or bark, wbicb appear
to be merely states of other genera ; the
epii^liytic Antennarice are referred to Capno-
dium, which, like Zusmidimn (Antenn. cel-
laris), is a Perisporiacea. Two other genera,
Pkuropyris and Pisomyxa, were described
by Corda, but little is kuown respecting
them.

BiBL. Fries, Summa Veg. Scan. p. 400 ;
Berkeley, Cn/pt. Bot. i). 296.

ANTENN'ULA'HIA, Lamk.— a genus
of Hydroid Zoophytes, family Plumula-
riidse.

Distinguished by the whorled, hair-like
branohlets, and uniserial cells. Two British
species : —

A. antonnina. Main stalks simple, clus-
tered, branchlets short. On sandy soils and
stones lying in sand ; deep water.

A. ramosa. Main stalks branched. On
old shells and stones from deep water.

BiBL. Johnston, Brit. Zooph. 85; Gosse,
Mar. Zool. i. 24 ; Hincks, Brit. Zooph.
p. 279.

ANTHER.— The essential part of the
male or fertilizing organ of Flowering
Plans, supported on a longer or shorter stalk
or filament, and constituting with it the
stamen. The microscopic examination of
anthers turns in two distinct, both very in-
teresting directions, namely, study of the
development and characters of the pollen
produced in the anthers, and examination
of the celhdar structure of the walls of
the perfect anther. For the former, see
Pollen,

The cells of the anthers of almost all
plants exhibit depo.sits of a more or less
fibrous character, ^•alying much in the pat-
terns according to which the fibres are

placed, and the extent to which they are
developed ; and these are elegant micro-
scopic objects.

The anther is clothed with a very delicate
epidermis, sometimes provided with sto-
mata ; this epidermis usually remains un-
altered, but in some cases {LupinKs} the
walls acquire fibrous thickening. Beneath
this epidermis ordinarily lie one or more
layers of cells which form the spiral-hbruus
tissue.- This may extend all round the
anther, or be wanting at certain points,
especially over the connective, before and
behind ; sometimes all the cellular tissue of
the connective itself assumes the same cha-
racter (with the exception of its vascular
bundle) .

Purkinje has furnished a most extensive
notice of the conditions of these fibrous cells
in the diflerent families of Flowering Plants.
The following plants are selected as afford-
ing considerable diversity of forms : —

a. Spiral fibres. Narcissus poeticus, Po~
jmlus alba, Lonicera tartarica, Hi/oscyamHS
orientalis, Datura Stramonium, Cheirantlms
Cheiri (PI. 40. fig. 1).

b. Annular fibres. Iris florentina, Ilya-
cinfhus orientalis, Bunias orientalis, Chei-
ra)dJius Cheiri, Convallaria.

c. Reticulated fibres. Fritillaria imperi-
alis (on the internal face), Tu'lipa Gesncriana
and Viola odorata (ditto), Saxifraga urn-
brosa (PI. 40. fig. 2).

d. J'ibres arched (found on three sides of
the walls, the fourth being free). Knphar
lufea, Bryonia diuica, Cynoglossiim, Pulmo-
naria, Prijmila sinensis, Passijlora coirulea,
Liqiistrmn rnlt/arc, Cucurbita, Pyriis, Liipi-
m'ls (PI. 40. fig. 3).

e. Plbres short and straight, pieces upon
the walls standing vertically to the epider-
mis. Arum, Calla cethiopica, Calceolaria,
Delphiniu m, Anemone.

f. Like d, but converging towards the
centre of the upper wall of the cell, some-
times forming a star. Corydalis lutea, Im-
patie)is, Fumnria, Cactus (PI. 40. fig. 4),
Polygonum, Tropfculum ma jus, J^eronicajier-

fvliata, Pvlygida Clianuehu.rus, liubia tine-
torum, Armeria.

g. Fibres vertical, very short, numerous
and close, like teeth on the walls. Grasses,
Casuarina, Jlyosotis, Phlomis fruticosa,
Bobinia, Adonis vernalis, Glauciwrn luteum,
Chelidonium majus. Magnolia^ Liriodendron,
Daldia, Le(mtodon, Solidago, Bellis percnnis
(I'l. 40. fig. 5), Geranium, Pelargonium,
Pinus, Cupressus, Juniperus.

I

AJsTTIERIDIA.

[ r>7 ]

ANTIIINA.

/*. The walls simply thickened like wood-
cells. Zamia.

Other iutermediate modifications exist;
and it is necessary to observe that the cha-
racter of th(Munrkino-s often diifers in dif-
ferent parts of tho wall of the anther. The
side of the cell-wall next the cavity is that
generally most marked ; the onter wall lying
next under the epidermis is often smooth
and unmarked.

A similar structure is found on the walls
of the sporanges of many of the Hepaticae,
such as Marchantia (PI. 40. fig. 35), Junger-
mannia, &c. (see 1Iep.a.tic^i;). Also on the
walls of the sporanges of Equisctnin (see
Equisetace^). For further particulars
respecting the relations of these cells to
other spiral-fibrous tissues, see Spiral

STRrCTUEES.

BiBL. Purkinje, De cell, anther. Jibrosis,
Wratislavij-e, 18.30; Sachs, JBot. 1874,
525.

AXTHEPJUIA.— The general name ap-
plied to all the various structures in which,
certainly or probably, the f ertiliziug function
of reproduction resides in Flowerless Plants,
and which consequently correspond physio-
logically to the anthers of the Flowering
Plants. They differ to some extent in the
character of the final products, which are
extremely minute bodies, some exhibiting
spontaneous motion when placed in water.

The antheridia of the higher Flowerless
Plants, those with leaf and stem, produce
active filaments, coiled more or less in a
spiral form, and the motion is here connected
with the presence of cilia upon the spiral fila-
ments. With regard to those of the Thallo-
phytes, the antheridia are not everywhere
so well imderstood. Their existence is
clearly ascertained in the Fucacese, and the
active bodies are ciliated. The function of
the so-called antheridia of the Floridetie is
not yet proved, and it is denied by Thuret
that the autherozoids (or spermatozoids)
have a power of motion ; recent researches
among the Confervacese have shown the
existence of antheridial cells, producing
active spermatozoids, to be very general in
that order. In the Fungi and Lichens the
antheridia seem to be represented by a dif-
ferent kind of structure, Avhich produces
minute stick-shaped bodies, apparently not
endowed with spontaneous motion.

The moving bodies from the antheridia
are called spermatozokh, anthei-ozoich, or
spermatic flauienU in the higher Crypto-
gamia. The active bodias of the Fungi

Fig. 23.

and Lichens have been provisionally named
spcrmaiia.

The antheridia of the Marsileacese are re-
presented by the smaller form of spore pro-
duced in the sporanges (see Marsileacese).
This is also the case in regard to the Ijvco-
podiaccte so far as Schtijinella and Isoetes
are concerned (see Lycopoi)IACe.t3). In the
Ferns and Equisetacere the antheridia are
produced along with the
archegonia on the prothal-
lium or cellular frond re-
sultino- from the gei-mina-
tion of the spure (see
Ferns and Ecjuiseta-
CE^) . In the Mosses and
leafy Liverworts, the an-
theridia are produced in
terminal or axillary buds,
associated with or sepa-
rate from the archegonia
(fig. 23). In the fron-
dose Liverworts, they are
imbedded in the frond, Bartramia fontana.
or more or less raised Male inflorescence
from it on special recen- "^'^^ antheridia and
tacles (see Mosses and nified 40 diameters.
Hepatic^).

The antheridia are represented in the
Characeaj by the so-called globule, in which
are produced filamentous spermatozoids re-
sembling those of Mosses (see Chara).

Antheridia occiu'in Saprolegnise (Prinirsh.
Jahrb. Bd. vi. p. 249 &c. ; Tab. Fungi, fi^.
20), and have been observed in Tuber and
Peziza. (See Pringsh. Jahrb. Bd. ii. p. 378
&c. ; De Bary, Ajin. d. Sc. Nut. Juin 1806,
p. 343 ; Tidasne, ibid. Dec. 1860, p. 211.)

The supposed antheridial organs of the
Lichens are called spermof/otiia, and will be
found described under Lichens; and the
analogous structures found in certain Fungi
called by the same name, are described
under Coniomycetous Fungi, also imder
the heads of certain genera of that family.
The antheridia of the Algfe are described
under Frcus, Floeide^, CEdogonxltm,
Vauciieria, Sph^roplea, Volvox.

ANTIIEROZOIDS.— The term applied
by the French authors to Spermatozoids.

ANTHTNA, Fries. — A genus of Isariaeei
(II_^^ihomycetous Pimgi); composed of mi-
nute fibrous plants, often of bright colours,
growing upon dead leaves &c. in autumn.
One British species is recorded : —

A.Jla)nmea,Yv. Attenuated downwards,
smooth, crimson-safiron, dilated upwards,
feathery, yellow. Clavaria miniata, Purton.

ANTHOCEROS.

[ 58 ]

ANTHOPIIORA.

-A genus of
Fig-. 24.

A beautifully coloured Fungus, varying as
to the degree of ramification, scarcely 1-2"
thick at the base ; thickened up>vards, as also
are the branches ; fibrous and feathery at
the summit ; solitary ; from 1-2" to 1" high ;
turning blackish when dried. The spores
separate very readily when the specimens
are placed in water for examination.

It may, however, be doubted whether
even AntlnnaJJammea, Avhich occurs occa-
sionally in considerable quantity'- amongst
dead leaves in shady woods, is an autono-
mous fungus, though it may be difHcidt to
point out of what species it may be a state,
unless it be related to Thelephora multizo-
natd, Berk.

BiBL. Purton, iii.t.18; Nees and Henry,
Syst. d. nize, 1837, t. 6 ; Fries, Siimina
Veqet. p. 405.

ANTHO'CEROS, Mich.-
Anthocerotete (Ilepaticfe).

The forms found in Britain
are regarded by Hooker as
varieties of one species. B}'-
thecontinental botanists they
aredividt'd into two : A.punc-
tdtus, Avith the frond dotted
and divided at the margin ;
and A. Iccvis, Avith the frond
smooth (fig. 24).

These plants are found in
very moist situations, at the
sides of ditches kc, fruiting
in spring. The ovate-oblong
fronds are from ^ to f of an
inch long, lying flat, and
often forming round patches,
overla]3ping one another, ra-
diatiue- from a centre, and . ,, , •

more or less divided at the Mn{,mif5etl 2dia-
margin. The texture is be- metura.
tween membranaceous and tlesliy, inclining
to the latter; the colour deep green, lighter
at the margins. The antheridia and arche-
gonia are usually abundant on the same in-
dividtinl. The antheridia are spherical, with
short stalks, of a yellowish-orange colour,
included in cup-shaped, deeply toothed re-
ceptacles on the upper face of the fronds.
The young archegonia differ from those of
any other Ilepaticfe in their structure, since,
instead of free, flask-like cases, they are
tulnilar cavities running down from the
upper face of ihe frond, with an embryonal
cell at the bottom, which increases by de-
grees into a conical body, and finally emerges
on the surfac(>, surrounded by a perichrcte
continuous with the epidermis of the frond.

The conical body by degrees grows up into
the narrow pod-like sporange, which attains
a length of about 2 inches, and is supported
on a short pedicel, 2 to 3 lines high, almost
concealed iu the perichfete. The sporange
splits down the middle into two valves,
which become slightly twisted, and leave
in the centre a thread-like column, to which
adhere for a time many of the spores and
elaters. The spores, — the development of
which has been a subject of much study, and
is very instructive, — from the long sporange
containing specimens of successive!}'- older
formation from one extremity to the other,
— are of the ordinary character of these
tribes, having a reticulated outer coat,
nuirked by ridges indicating the mutual pres-
sure of the four spores formed iu each parent-
cell. The elaters are much simpler than
usual, consisting merely of membranous
tubes, not very long, but sometimes irregu-
larly curved or branched, without any spiral
fibre in their interior. Gemmae also occur
on the frond oiAnthoccros.

BiiiL. Dev. ofthe Fruit generally: Ilof-
meister, Ilohern. Knjptoyanten, Leipsic,
1851 ; Schacht, Entio. cl. Fnicht unrl Spore
V. AnfJioceros Icevis, Boi. Zei'. 1850. Spores :
Mohl, Lhuwa, 18;]9 ; Vennischte Schrift.,
Tubingen, 1846 ; Nageli, Veyet. Cells {liay
Society), 1840, p. 229; Carrington, Bnt.
Hep., 1881 ; Sachs, Bot. 351.

ANTIIOCEROTE.E.— A tribe of Liver-
worts or Ilepaticfe (which see), containing
one British genus, Anthoceros.

ANTHOPHUltA, Latr.— A genus of
Insects, of the order Ilymeuoptera, and
family Apidfe.

Cliur. Wings with three complete sub-
margi nal cells of equal size ; labial palpi with
the third joint afhxed obliquely; maxillary
palpi 0-jointed; intermedifite legs of male
with long brushes of hair.

There are two species, A. rctusa and A.
Ilmcorfhdita.

A. rctusa (mason bee) is commonly seen
flying about sunny and sandy banks from
March to the beginning of June. Its head
and tropin are represented in I'l. 3."». fig. 24.

The (uitonuc [<t) are inserted in the centre
of the fiice, not approximating, short, geni-
culated, and L')-jointed in the male; basal
joint (scapus) very pubescent, second (pedi-
cella) globose, third as long as the first,
fourtli shorter than any of the following,
which are oblong ; they are similar in the
female, but a little longer, and 12-jointed.
Lahriim (<0 deflexed, convex, with two black

ANTIIOPIIYSA.

[ ^0 ]

ANTLIA.

spots at tlu' hdso, antevior margin a little
convex aiul ciliated. Mandibles (/) slightly
curved, clothed ^vith long hairs, notched
near the apex; larger iu the females, and hut
slightly notched below the apex. MaxilUc
((/) with the basal portion short and broad,
hairy, the edge above pectinated, terminal
lobe long and lanceolate, with a small pencil
of hairs at the apex. Palpi {h) rather long
and setaceous, G-joiuted, basal joint short,
second long, the remainder decreasing in
length. Mentam rather short and linear.
TinKjue (*) very long and slender, ringed and
tubular, the interior margins very pilose,
terminated by a lanceolate appendage. Pa-
7-af/l(>sscc (.v) lanceolate. Palpi (k) extend-
ing as far as the tongue, slender, tapering,
4-jointed, basal joint very long, second not
b.alf the length, ciliated towards the apex,
third inserted below the apex, and very
small, as well as the fourth. Head sub-
trigonate ; eyes (c) long and narrow ; ocelli
(b) three. Thorax much broader than the
head in the female. Legs rather robust ;
tibiffi, posterior dilated and very pilose ex-
ternally, .and the intermediate ones also in
the females ; tarsi, intermediate pair long in
the males, the basal joint of the 4 posterior
dilated in both sexes, and furnished with a
strong brush at the apex in the hinder pair
of the female. Claws bilid in the males,
with a tooth on the underside in the female.
Pulvilli distinct. Male thickly and minutely
punctured, and clothed with fulvous or yel-
lowish hairs, more or less black at the apex
of the abdomen ; female black, very pilose.
See Insects.

BiBL. Curtis, Brit. Entomol. viii. p. 357 ;
Westwood, Infrod. &c. ii. p. 277.

AKTIIOPHY'SA, Duj.— A genus of In-
fusoria, of the famih' Monadina, Duj. ; Fla-
gellata, Kent.

Char. Bodies ovoid or pyriform, with a
single anterior flagellifcrm filament (two,
one shorter than the other, Kent), and ag-
gregated at the ends of the branches of a sup-
port or polypidom, which is secreted by them.
The groups, when free, resemble UvcUa,
and revolve in the liquid containing them.

The branched support is of an irregular
arborescent form, at first soft and glutinous,
afterwards becoming bro^\T:ish, horny, and
nodidar in appearance. According to Cohn,
the brownish filaments so frequently found
in decomposing^ pond- &c. water, are the
stalks of Anthophijm, and form Kiitzing's
genus Sfereonema.

A. MiUlcri {vcfjefans) (PI. ?,0. fig. 1.3).

Body thicker in front ; length of stalks 1-2-50
to 1-120", length of single animal 1-2000",
P^ig. 13 b represents a detached animal with
the larger tiagelliform filament. This is the
EpistyUs vc(j('taus of Ehrenberg. The de-
tached groups of bodies form a species of
Uvella, Ehr. ( Uvella uva ?). Fresh water,
common.

A. socialis. Bodies about 8 in a group.
On Confervas.

BiBL. Dujardin, Infus. ; Ehr. Inf.; Cohn,
Nova Acta, 18o4, p.' lOU; Ann. N. Hid.
186(;, xviii. p. 429; Kent, Inf. p. 2(')G.

ANTIIOSO'MA, Leach. — A genus of
Crustacea, of the order Siphonostoma, and
family Ergasilina,

Found upon the gill-covers and gills of
sharks.

BiBL. Baird, Brit. Entom. ; Desmarest,
Cons, gcner. sur I. Crustac.

ANTIGRAM'MA, Presl.— A genus of
Scolopendriete (Polypodiaceous Ferns). Ex-
otic.

ANTIMONIATE of soda.— The produc-
tion of this salt by the addition of antimo-
niate of potash to a neutral or alkaline solu-
tion of a salt of soda, is used as a test of the
presence of soda. The crystals are repre-
sented in PI. 10. fig. 21.

BiBL. See Chemistry.

ANTIMONY. See Aesenic.

ANTITRICHIA, Br. and Sch. = NEC-

KEEA.

ANT'LIA. — The spiral tongue or probos-
cis of the Lepidoptera.

Tliis well-knowni beautiful organ (PI, 33.
fig. 28), when extended, forms a long sucto-
rial tube, and when coiled up represents a
flat spiral, like the spring of a watch. It
consists mainly of two modified maxillte
(see Insects). According to Newport,
each maxilla is composed of an immense
number of abort transverse muscular rings ;
these are convex externally and concave
internally, and the two connected organs
form a tube. "Within each there are one or
more large tracheae (fig. 28 c* J) connected
with the trachea} in the head. The inner
or concave surface which forms the tube
(fig. 28 ct) is lined with a very smooth
membrane, and extends along the anterior
margin throughout^he whole length of the
organ. At its commencement at the apex
(fig. 28/*), it occupies nearly the whole
breadth of the organ, and is smaller than at
its termination near the mouth, where the
concavity or groove does not occupy more
than about l-3rd of the breadth. In some

ANTROPHYUM.

[ CO ]

ANYSTIS.

species, the extremity of each maxilla is
furnished along its anterior and lateral
margin with a great numher of minute
papillae. These, in l^aufssa Atalanta (the
red admiral butterfly) for instance, form
little barrel-shaped bodies (tig. 28 6, «,/),
furnished at the free end with three or more
marginal teeth, and a larger pointed body in
their centre. There are seventy-four of
these in each maxilla, or half the proboscis.
Newport regards them as probably organs
of taste. There are also some curious ap-
pendages arranged along the inner anterior
margin of each maxilla, in the form of
minute hooks, which, when the proboscis
is extended, serve to unite the two halves
together, by the points uf the hooks in one
half being inserted into little depressions
between the teeth of the opposite side ;
sometimes these are furnished with a tooth
below the apex (fig. 28 e).

This description of the structure of this
interesting organ does not appear to be
correct. We believe that the older view,
regarding each half of the AntUa as con-
taining a distinct canal, to be true, and
that the transverse rings, in fact the entire
frame-work of the organ, consists of chitine.
But the subject requires further investiga-
tion. The only muscular structure we have
detected in the organ, consists of bundles of
muscular hbres taking an oblique longitu-
dinal direction.

BiBL. Newport, TodcVs Cycl. of An. and
rhys. ii. p. 901 ; Hicks, Linn. 'Tr. 18G0,
xviv. p. 148. See also Insects.

ANTROTHYUM,
Kaulf. — A genus of
I'olypodiaceousFerns,
fam. Grrammitideae.

Char. Sori carried
along the veins, im-
perfectly reticulated,
superficial or immers-
ed in a groove.

Fronds simple, of
firm fleshy texture,
with uniform hexago-
nal areolae. 10 species;

■ XT 1 r. Antrophyumplantagineum.

BiBL. Hooker, O/J. Partofasorus. Magnified.

Fil. p. 302.

ANUR/E'A, Ehr. — A genus of Rotatoria,
of the family Brachionsea.

Char. A sing](> (red) eye-spot at the back
of the head, no foot or pediform tail.

In seven species the back of the carapace
is furnished with facets, in four with longi-

Duges ;

Arach-

family

tudinal strife, in three it is smooth ; in
thirteen it is furnished with teeth or spines
in fr(int, in seven also behind. One species,
A. hiremis, has two moveable spines on each
side.

Dujardin gives the following characters.
Carapace in the form of a depressed utricle
or sac, toothed in front and with a wide
orifice to allow of the protrusion of the rota-
tory organs, which are usually well developed
in th6 form of two rounded lobes, accom-
panied by setoe or non-vibratile cilia in
several bundles ; no tail ; jaws digitate ; a
red eye-spot above the jaws; ova volumi-
nous, often adherent to the parent.

Tlie species are both aquatic and marine,
and many of them ai'e common in pure fresh
water ; length from 1-240 to 1-10".

Ehrenberg describes 14 species ; to which
Gosse adds 4.

A. curi-icornis, E. (PI. 4.3. fig. 5, viewed
from above : fig. G, side view).

BiBL. Ehr. hifus. ; Buj. tnfus. ; Gosse,
Ann. N. H. IBol, viii. p. 202. "

AN YS 'TIS, Heyd. {Enjfhrmis,
Tromhidiuni, Herra.). — A genus of
nida, of the order Acarina, and
Trombidina.

Cluir. Palpi large, free, bi-unguiculate ;
mandibles uuguiculate ; body entire ; legs
at thi-ir insertion contiguous, cursorial, i. e.
uuguiculate, long, the last joint slender and
very long ; posterior legs the longest.

A. pariefinum. Colour vermilion; legs
pale. Found between stones and in moss ;
and on book-shelves. Tromb. parietiniim,
Ilerm. 3Icm. Apt. p. 37, pi. 1. f. 12.

A. ruricola. P)ody very minute, depressed,
nearly oval, slightly emarginate at the sides,
and broader behind than before; a few
hairs scattered over the surface ; eves two,
black, placed at the anterior obtuse angles
of the body; colour bright carmine, some-
times blacldsh in the middle, paler along
the back and in front ; legs and palpi colour-
less, except a bright red spot on each at a
little distance from the body. On stones
and on dry paths. (PI. 60. fig, 4, and PI. 2.
fig. 3.)

A. flava. Yellow.

A. if/nipes. Mottled with greyish brown
and yellowish red.

A. cuisoria. Rose colour.
A. cornif/fira. Red with two blackish
lines down tlie back.

Actiwda, Koch, is not generically dif-
ferent from A/ii/s/is (Murrav).

BiBL. Hermann, Mem. ApteroJ. ; Duges,

APATITE.

[ 01 ]

APIIID.E.

Aim. (I. Se. Xaf. 2 sf?r. i. and ii.; Koch,
Deu/sch. Cruiif. ^c. ; Heyden, Isis, p. lOO ;
Gervais, Walckenacr's Hist. d. Ins. iii. ;
Murray, Econ. Enfom. p. 1-iO.
APATITE, see Rocks.
APIIANIZOM'ENON, Morren {Limno-
chlide, Kiitzing). — A genus of Nostoc-hacese
(Confervoid Algse) forming a delicate bhiish-
greeu mucous stratum on the surface of lakes
or standing water. The filaments are very
slender, tiaccid and obscurely jointed. The
spermatic cells are much elongated, either
scattered or, more frequently, solitary near
the ceutre of the filament. AUman inclines
to think they are formed by confluence of
adjacent cells ; he found vesicular cells
(heterocvsts) also, which Ralfs did not de-
sc'iibe. This genus seems to form a con-
necting link between the OscillatoriacesB
and Nostochacete, as indicated by Hassall.
Ivalfs enumerates three British species,
viz. —

A. Flos-aqucs, Linn. (PI. 8. fig. 1).— Fila-
ments about 1-3000" in diameter, cohering
laterally in flat lamellae which separate at
their extremities into fasciculi ; spermatic
cells cylindrical, with an inconspicuous co-
vering.—Ralfs, A7i. N. Hist. 1850, v. pi. 9.
fig. (j; Limnochlide Fhs-aquce, Klitz. Tab,
rhyc. cent. i. pi. 91. fig. 2 a.

A. cyaneum, Ralfs. Filaments free, ag-
gregated into a thin mucous stratum ; spo-
rangia linear, 8 to 12 times longer tlian
broad, with a conspicuous hyaline covering.
— Ralfs, I. c. pi. 9. fig. 7. Limnochlide Flos-
aqiue, var. hercynica, Kiitz. Tab. Phyc, c. i.
pi. 91. fig. 11 .P

A. incurvimi, Morren. " Filaments arti-
culated, cohering together in flat laminae,
laciniated at the apex ; articulations 2 to 8
times longer than broad." Ralfs states that
the Irish specimens identified by Morren
do not agree with this character, being held
together by the mucous matrix rather tiian
cohering, as in Fbs-aqucs., and they are
neither fasciculated nor laciniated at the
ends. — Ralfs, I. c. pi. 9. fig. 8. Aph. incur-
vum, Thompson, An. N. H. 1850, v. 82 ;
Hassall, Algcs, t. 70. fig. 0. Limnochlide
Flos-aquce, var. Harveyana, Kiitz. I'ab.
Phyc. c. i. pi. 91. fig. 2.

liiBL. Ralfs, Ann. N. Hist. 1850, v. 3-39;
AUman, Qu. Mic. Jn. iii. p. 21, and the
other works cited above.

APHANOCAP'SA, Niig.— A genus of
Confervoid Algfe ; consisting of spherical
gi-een cells, imbedded in an amorphous ge-
latinous mass.

A. virescens (PI. 3. fig. 2). On wot rocks
and stones. Other species.

RiDL. Rabenhorst, Fl. Ah/, ii. p. 48.
APIIANOCILETE, Braun.— A genus
of Chfetophoreaj (Confervoid Alg;c) allied
to Coleochcete ; tlie bristles arising from tlie
backs of the ceUs are not sheathed, but
jointed in the upper part. Not yet detected
in Britain.

BiBL. Braun, Verjuity. p. 19G (Ray Soc.
transl. 1853, p. 184j ; Rabenhorst, A!y. iii.
p. 390 (fig.).

APIIANOTHE'CE, Niig.— A genus of
Confervoid Algse.

Cliar. Cells minute, rounded or oblong,
seruginous, enclosed in a gelatinous en-
velope.

A. 7nicroscopica (PI. 3. fig. 3). In marshy
places, everywhere. Many other species.
BiBL. Rabenhorst, Alt/, ii. p. 63.
APHTDvF:.— A family of Insects belong-
ing to the order Hemiptera (Homoptera,
Westwood). This family comprises the
insects known as plant-lice.

Rostrum more or less perpendicidar or
inflexed, varying in length, being in some
species longer than the body, and consisting
of four joints (PI, 36. fig. 1). Labrimi
long and pointed at the tip. Antennae of
moderate or of great length, setaceous or
filiform, and usually composed of 3-7 joints,
the last joint being sometimes obsolete and
the third longest (PI. 36. fig. 2). Ocelh
three to six in number, forming a large tri-
angle ; eyes compound, prominent, and semi-
globose. Thorax oval, with the prothoi'ax
forming a transverse coUar ; abdomen short
and convex, ovate or elongate-ovate, soft,
and generally furnished with a more or less
elongated tubercle or cornicle on each side
near the extremity. Wings, when present,
four; the anterior much larger than the
posterior, placed obliquely or nearly per-
pendicularly on the sides of the body in re-
pose ; the anterior with a strong subcostal
nerve, terminating near the apex in a broad
stigma, and giving off" two or three obUque
nerves rimning to the posterior margin of
the wing ; of these the one nearest the apex
is usually forked once or twice. These
variations in the arrangement of the post-
costal nerve form "the distinguishing cha-
racters of the Tribes (Buckton). A papilla
with three bent hooks on the costal margin
of the hind Avings, works in a fold of the
posterior margin of the anterior wing, some-
what as in tlie Ilymenoptera. Legs usually
very long and slender, with the thighs some-

APIIID^E.

[ 62 ]

APHID.E.

times thickened; tarsi two-jointed. The
body is sometimes clothed with a mealy or
cottony secretion, secreted by roundish
warts which stand in rows upon the back ;
in some t-pecies this covering is so long that
the animal is entirely concealed by it, and
looks merely like a moving flock of wool.
It is sometimes employed by the females as
a covering for tlieir eggs.

The Aphidte, hke the rest of the order to
which they belong, are active in all their
stages ; the pupfe being distinguishable from
the perfect insects only by their possessing
the rmliments of wings upon the back of
the thoracic segments. In the wingless
species this distinction of com-se does not
exist.

These insects reside, usually in large
societies, upon almost every species of
plant ; but the ditlereut species of plant-
lice, like the true lice of animals (Anoplura),
are generally restricted to one or two parti-
cular plants ; or when they are common to
a greater number of vegetable species, the
latter are usually very nearly allied. Each
species is also restricted to some particular
part of the plant ; but no part is exempted
from the attacks of particular species, which
are found upon the young shoots, the buds,
the leaves, the stem, even of trees, and the
roots. Of these parts they suck out the juices,
by placing the rostrum in a pei-pendicular
position, and forcing the included bristles
into the tissues of the plant ; the v>-ouud
thus formed is frequently enlarged by move-
ments of the body of the animal. In some
instances the irritation caused by these
Avounds, inflicted by a colony of Aphides,
gives rise to a distorted state of leaves and
twigs, and even to gall-hke excrescences, in
the interior of which the insects may be
foimd iu great numbers.

The abdominal tubercles or tubes above
mentioned, wliich, however, are reduced to
simple openings in some species, are gene-
rally regarded as excretory organs, through
wliich a saccharine fluid is exuded. This
ii uid is pn >duced by nianv Apliides, especially
those which live upon trees and shrubs, in
great abundance ; it constitutes the well-
known honey-dew, which drops in large
quantities from some of our common trees
(particularly the Lime), and forms small
t>liiniug spots upon their leaves. The latter
were supposed by Liebig to be products of
a disease of the plants upon Avhich they
occur. The sweet fluid is much hked by
ants and other llymenopterous insects,

which seek the Aphides for the purpose of
sucking it from them, sometimes inducing
them to excrete it by stroking them with
their antennte, but sometimes biting and
tearing them to get at it. Kaltenbaoh con-
siders the abdominal tubes to be merely pro-
duced stigmata, and states that the saccha-
rine fluid is emitted through the anus; this
is also the opinion of De Geer, K}ber, and
others.

The propagation of the Aphides presents,
some most remarkable peculiarities, and is
well worthy of a careful study. The ordinary
colonies of these insects, which may be met
with eveiy where during the summer, consist
of winged and wingless individuals, the
latter being for the most part larvfe and pupaj.
The winged individuals are all viviparous and
capable of producing young larvte without
any intercourse with a male insect. During
the whole course of the summer, none but
these so-called viviparous females are to be
met with, and generation follows generation
without the appearance of a single male.
It is only in the autumn that males and true
females are produced as the last result of the
viviparous reproduction ; the latUn' are
usually apterous, even in the ordinarily
winged species ; and, after copulating, the
females lay eggs, which serve to continue
the race in the following summer. The
viviparous individuals of some species are,
however, said to live through the winter ;
and the viviparous reproduction may be con-
tinued uninterruptedl}' for an indeflnite
period by the maintenance of the necessary
conditions of temperatiu'e &c. ; at least
Kyber observed it for four consecutive
years in a colony kept in a room at a uni-
form temperature. The males are rarer,
mostlj' alate, and with a smaller abdomen.

The true nature of this wonderful mode
of propagation has been the subject of much
dispute, especially of late years. It will be
unnecessary for us to enter upon the con-
sideration of tlie various opinions that have
been put forward ; it is sufucient to mention
that it is now generally admitted to be an
example of the alternation of generations or
parthenogenesis, which occiu's so frequently
amongst the lower animals, — the viviparous
forms being regarded as the products of a
sort of internal gemmation. According to
Huxley, the organs in Avhich the j'oung of
the viviparous forms are produced ( pseitdo-
van'a) are strictly homologous with the true
ovaries, and the germs of both forms are
identical, (the existence of the germinal spot
I

APHIDiE.

[ G3 ]

AniRODlTA.

in the pseudova is, however, denied) ; but
in the oviparous females, the germ is sur-
rounded by a vitellus and vitelline mem-
brane in the usual way to form a true egg ;
whilst in the viviparous individuals the
germinal vesicle itself enlarges and under-
goes a considerable change bef(5re acquiring
an investing membrane, within which the
embryo is gradually developed. Balbiani,
however, maintains that the viviparous
Aphides are really hermaphrodite.

From the nature of their production, it
will be easily miderstood that the fecundity
of the Aphides must be very great. The
most prolific species only live for about three
weeks, and in that time produce 30-40, or,
according to Reaumiu", 90-100 j'oung. In
these species there may be from 15-17
generations in the course of the summer ;
and Schrank, starting from Bonnet's obser-
vations, calculated the total theoretical pro-
geny of a single Aphis in the course of one
summer at 23,740,000. Their numbers are,
however, constantly kept in check by the
attacks of numerous enemies, amongst which
we may mention the common Lady-birds,
both in their larva and perfect states, the
larva3 of the Dipterous genus Syrphis, and
of the Hemerobiidfp., which prey upon them ;
whilst many of the smaller Ichneumonidse
and Chalcididee attack them for the pm-pose
of depositing eggs in their bodies.

Notwithstanding these checks upon their
production, the plant-lice increase suffi-
ciently to render them exceedingly injurious
to cultivated plants. The most noxious
species are the turnip-flv {Aphis BrassiccHj
PI. 3(3. fig. 3), the bean-fly {A. Papaveris),
which also occurs upon the poppy and
various other plants, and the hop-ily (A.
Humiili). The latter, when it abounds to
an unusual extent, causes the almost total
destruction of the crop of hops. One of the
most abundant species is the rose-fly (A.
Hgscs), which is often exceedingly injurious
to roses in gardens, by attacking the young
succident shoots. Lac/unis Quercus, a large
species with the rostrum three times the
length of the body, is found in the fissures
of the bark of old oaks ; the other species
of Lachnvs live for the most part upon the
shoots and leaves of coniferous trees ; the
commonest is L. pinicola. Eriosoma lani-
(/era (PI. o3. fig. 3) is a common species
upon the stems of apple-trees, hving in
societies in cre-sices of the bark, on which
it forms small, white, woolly patches. Te-
traneura Ulmi (PI. 36. fig. 4) lives in small

gall-like excrescences on the leaves of the
elm ; and the Peniphi;/as hwsarius (PI. 30.
fig. 5), a woolly species, resides in similar
galls on the leaves and foot-stalks of the
poplar. Of the subterranean species, which
suck the roots of plants, the most abundant
is Trama radicis (PI. 30. fig. 0), wliich
occurs upon various composite plants, in-
cluding the common dandelion and the
garden-lettuce. Forda fonnican'a (PI. 36.
tig. 7) is the species commonly found in
ants' nests ; it fives in small societies on
the roots of grasses, and is tended with
great care by the ants. Phi/Uoxera vasta-
trix (PI. 53. fig. 7) is the vine-pest.

The colouring-matter of the Aphides
partakes of the nature of chlorophyll
(Sorby).

BiBL. Westwood, Introd. 8,-c. ; Walck-
enaer. Hist. d. Ins. ; Kaltenbach, Moiiof/. d.
PflanzenldKse, 1843 ; Koch, Aphiden, 1857
(tigs.) ; Burnett, Sillimayi^s Jn. 1854, xvii.
pp. G2,_ 2(31 ; Walker, Ann. N. Hist. 2nd
ser. i. ii. iii. iv. &c. (1848-49) ; Claparede,
Ann. N. Hist. 1867, xix. p. 300; Balbiani,
ibid. 1866, x^iii. pp. 62, 106 ; id. & Signoret,
ibid. 1867, XX. pp. 20, 149 ; Boisduval, En-
torn. Horf. p. 240 ; Iluxlev, Linn. Tr. xxii.
pp. 193, 221; Sorby, Tr. Mic. Soc. xi. p. 352;
Buckton, Apliides (^3Ionogr,), Pay Soc.
1876.

APPIRODITA, L.— A genus of Annti-
lata. One species of this genus {A. acidenta)
is well known as the sea-mouse, and is
commonly found on the sea-coast, and
always admired on account of the splendid
iridescent colours reflected from its spines
and bristly hairs. Body from 3 to 5 inches
long, Ih broad, and oval ; back of an earthy
colour. Head small, entirely concealed,
with two round clear spots, or oyes, on the
vertex. The hairs and brist'es run down
each side of the body ; the back is rougliish,
with a thick felt of hair and membrane
forming a kind of skin. When this is cut
through, fifteen nearly circular plates or
scales (elytra) are found on each side,
which partly coA-er each other. If two of
the plates lying next each other be sepa-
rated, we then see up(ni the intermediate
ring small tubercles divided by a pit, fur-
nished behind with -pectinate appendages,
the gills or branchitc.

Antennas minute ; palpi large, subulate,
jointed at the base. Month with a large
retractile edentulous proboscis ; the orifice
encircled with a short, even, thick-set fringe
of compound penicillate filaments divided

APHROSIXA.

[ G4 ]

APIOCYSTIS.

into two sets by a fissure on each side.
Tliirtj-uine pairs of feet, biramous ; the
upper branch carries the long-, flexible,
brilliantly coloured bristles forming the silky
fringe ou each side of the body.

This animal is a very interesting object
to the microscopist, as its tissues are very
transparent and easily examined.

The brilliant colours of the bristles and
hairs arise from iridescence, produced by a
number of longitudinal stiise or interspaces
between the component fibres of -which the
bristles and hairs consist ; they also exhibit
transverse splits or cracks 5 they are not
materially changed by the action of boiling
solution of potash, except that the external
coat of the liau's becomes transversely wrin-
kled, giving these the appearance of being
surrounded by a number of fibres (PI. 49.
tig. 20).

BiBL. Johnston, Ann. N. Hist. 1839,
p. 430 ; Van d. Hoeven, Zool. p. 232.

APHKOSI'NA, Carter. — A minute, pa-
rasitic, poriferous Foraminifer, with nume-
rous irregular, vesicular chambers. Allied
to Caiyejiteria.

BiBL. H. J. Carter, J. Micr. S. ii. 500.

APHTHA. — A disease aftectiug the mu-
cous membrane of the mouth, tongue, kc.
It exhibits itself in the form of rounded
patches of larger or smaller size, of a whitish
or yellowish colour. One form of it, vul-
garly called the " thrush," and in French
mtir/uet, which occurs very frequently in
children, and in advdts towards the fatal
termination of chronic diseases, is of special
interest, inasmuch as the patches consist
of numerous epitb(>lial scales mixed with
the filanifuts and isolated cells of a fungus
{Oidium albicans). A poi-tion examined
under the microscope exhibits : — 1, nume-
rous oval cells (a, PI. 38. fig. 1), rarely con-
taining an internal globule or uiicleus ; 2,
long filaments (i) exhibiting a further ad-
vanced stage of development ; the filaments
are but rarely jointed ; 3, epithelial scales,
sometimes perfect (d), but usually wrinkled
and otherwise altered in form, and fre-
quently more or less opaque (c) , so as to be
hardly recognizable except when treated
with ' pota-h ; intermingled with these
bodies are sometimes vibriones or bacteria
{BacL tenno,f) and a molecular form of
matter (//), probably an early stage of Bad.
terino ; for it is always found witli and
prior to it in decomposing liquids, in addi-
tion to the molecular granules found in all
animal liquids.

This fungus appears to arise in the same
manner as other analogous fungi, as those
in kept organic liquids, in mine, &c. ; the
spores are probably always fioating in the
air and dropping from it upon all the ex-
posed parts of the body ; and wherever they
find a proper nidus, there they grow. In
diseases accompanying or preceding aphtha,
the regeneration of the oral e2)ithelium is
probably to a great extent checked, the
secretion of the saliva also, which would
wash away these organisms ; why they
occur so frequently in infants, is probably
owing to the saccharine natm-e of the diet,
which is especially favourable to theu' de-
velopment.

It is to be observed of the numerous
parasitic Fungi which have been described
as preying on animal tissues, that a great
portion are mere conditions of common
species of AspergiUns, Penkil/ium, Mucor,
&c., which as~ume difierent forms according
to the nature of the matrix. This has not
been sufficiently kept in view by authors
unacquainted with the genera of Fungi; and
in consequence, a great nimiber of spurious
genera have been proposed, and considerable
confusion has ensued ; while the fashion of
late with Ilallier and his followers has
been to confound things which are essen-
tially distinct. See Oidium.

BiBL. C. Robin, Hist. Nat. d. Vc(/. Para-
sites, 1853, p. 488, where many other works
are mentioned. .

APIOCYSTIS, NJigeli.— A genus of Pal-
meUaceaj (Confervoid Algce). Aquatic plants
parasitical upon Confervfe, consisting of
pear-shaped or clavate vesicles from 1-50"
to 1-2U" high, and about half as thick, at-
tached by the narrow extremity, and con-
taining numerous green primordial ceDs
about 1 -2500 to 1-3500" in diameter. Young
sacs contain regularly 2, 4, 8, lU, 32, &c. ;
and in large ones the number amounts to
300 to 1600. At first they lie _ iiTegularly
in the cavity, afterwards they lie upon the
wall in one or more layers ; sometimes they
are attached to the wall in groups of eight.
At a certain stage, the primordial cells be-
come again free in the cavity, move actively,
and finally escape by the rupture of the sac,
swarm as biciliated zoospores for a time,
then settle down and germinate.

A. Brauniana (PI. 5. fig. 5) ; in ditches,
&c. Brit.

BiRL. Niigeli. FJnz. Alr/en, p. G7, t. 2. A.
figs. 1 and 2 ; llonfrey, 7V. iU/r. Soc. I80O,
iv. p. 49, pi. 4 5 liab. Alt/, iii. p. 43.
I

APIS.

[ 65 ]

APUS.

A 'PIS, L. — A genus of Hymenopterous
Insects.

A. meUifica, the honey-bee, pi'esents some
interesting- points of structure.

The proboscis (PI. 3.3. fig. 2o) agrees
essentially with that of Anthophora. The
" tongue " (labium*) is a very beautiful and
favourite microscopic object ; its minute
structure requires a higher power than that
used in maldng our sketch, to render distinct
the elegant transverse ridges or folds and
the terminal liairy lobe.

The legs are peculiarly formed for the
special purpose of collecting and carrying
the poUen of flowers. The tibife of" the
hind legs are dilated, smooth on the outside
in the neuter or working bees, and hollowed
into a shining plate (PI. 34. fig. 46), whilst
the basal joint of the tarsi is hooked at its
outer superior angle and dilated into an ob-
long or somewhat triangular plate (PL 34.
fig. 4a), which is furnished with transverse
rows of hau's, forming pollen-brushes.

BiBL. Westwood, Intr. &c. : Cm-tis, Brit.
Ent. 769.

APLAXATISM. — Freedom from spheri-
cal aberration (in lenses).

APLIDIUM, Sav.— AgenusofMollusca,
of the order Tunicata, and family Botrjd-
lidae.

The common mass is from 1 to 3 inches
high ; and the animal bodies about J-| inch
long. Four British species : —

A. Jicus, dark olive, orifices six-rayed ;
A. fallax, honey-yellow, with white' and
brown specks, orifices circular ; A. 7mtans,
straw-yellow, tinted with brown, orifices
invisible; and A. ven-ucosum, olive-green,
orifices entire.

BiBL. Forbes and Hanley, Brit. MoUuxca,
i. 10.

APOTHECIUM.— The name applied to

Fig. 26.

Dirina Ceratoniae.

the female or spore-fruits of the Lichens,
^everal special names have been applied to

the apothecia, namely, pelta, scuteUa, patella,
scyphus, nrhiculus, lircUtt, and verruca, indi-
cating the forms occurring in particular

Fig. 27.

Fi£r. 28.

Fig. 27. Apothecia, magnified. Fig. 2S. Thecoe and
paraphyses, from a vertical section of an apotliecium,
magnified 200 diameters.

genera. They are shield-shaped, flat, cup-
shaped, globular, papilliform bodies, or linear
ridges, upon the upper surface of the thallus,
either immersed, superficial, or elevated on
peduncles. They contain the thecse or spore-
cases. For the structure, see Lichens.

APPENDICULARIA, Cham.— A genus
of Mollusca, of the order Tunicata, and
family Salpidae.

1 British species; A.JlagelUna.

BiBL. Gosse, Mar. Zoot. i. p. 37; Cha-
misso. Nova Acta Acad. Cur. x. ; Huxley,
Phil. Trans. 18-51, p. 59,5.

APTOG'ONUM, Ralfs.-A genus of Des-
midiacere.

Char. Filament elongated, triangular or
flattened ; joints bicrenate at the free mar-
gins ; an oval foramen between the joints.

Kiitzing and others placed this organism
in the genus Desmidiian, where it might
very well have remained.

A. Desmidimn. Joints in front view
quadrangular, broader than long.

a. Filaments triangular, regularly twisted,
crenatnres rounded ; length of joints 1-1-500",
breadth 1-1000" (PI. 14. fig. -5-5, front view ;
fig. 52, side view).

/3. Filaments flattened ; crenatnres shal-
lower and slightly angular.

A. Baileyi. P'ilaments not cronate ;
joints about equal in length and breadth.
American.

The latter cannot- be retained in this
genus, unless the characters bo altered, on
account of the absence of the crenatnres

BiBL. Kalfs, Br. Besmid. pp. 03, 208.

A'PUS, Scop. — A genus of Entomos-
traca, of the order Phyllopoda, and family
Aspidephora.

ARACHNIDA.

[ G6 ]

ARACHNIDA.

Char. Head, body, and oreater part of tlae
abdomen covered by a sbield-like carajjace,
"which is deeply notched behind ; eyes two,
sessile and approximate ; a single pair of
minute, short, styliform and two-jointed
antennas ; legs, sixty pairs, the first pair
furnished with three long jointed bi'auclies,
extending beyond the carapace, the rest
branchial ; body composed of numerous
rings ; two long jointed caudal appendages.

A. cancriformis. Freshwater, in stagnant
pools ; brownish yellow; length 2i inches.

A. produdiis. Not British ; an elongated
oval lamina between the two caudal appen-
dages.

BiBL. Baird, B)-if. Eijtom. p. 18 ; R. Lan-
kester, Qu. Mia: Jn. 1881, xxi. p. 343.

ARACHNI'DA. — A class of animals con-
taining the spiders, scorpions, Szc.

Char. Head united with the thorax,
fonuing a cephalothorax ; antennfe none ;
eyes simple (ocelli) ; legs eight, jointed.

The integument of tlieArachnida is usually
soft and leathery, rarely horny or brittle, and
consists principally of chitine. Two layers
may usually be distinguished, an outermost
or cuticle, which is tlie firmest and strongest,
and not unfrpqueutly exhibits a cellular ap-
pearance in the extremities and the cepha-
lothorax. The cuticle of the abdomen of
the Aranene, Acarina, kc. presents very
beautiful wa-vv' or undulating lines, some-
times surrounding the roots of the hairs &c.
concentrically, and arising, in some cases at
least, from the existence of folds (PI. 6. figs. 4
& 5). The cuticle of the Arachnida is fre-
quently covered with warty and bulbous
excrescences, bristles and simple or feathery
hairs, and sometimes with scales.

The innermost cutaneous layer consists of
a very delicate and almost colourless mem-
brane, of a finely granular or fibrous appear-
ance, close beneath which is situated a
layer of pigment granules and cells, which
are visible through the general integument,
and to which the beautiful colours of many
of the Arachnida are owing.

The organs surrounding the mouth varv
in structure in the difierent f\imilies. In the
Spiders, two mandibles are situated at the
front of the head. These consist of two
joints — a basal, very thick one (PL 6. fig. Ga
& 7 re), and a terminal, curved and shaiply
pointed one (fig. 0 6 & 7 h). The latter is
traversed by a canal terminating at its apex,
through wliich the secretion of a poison-
gland passes into any body transfixed by the
claw. These mandibles are perhaps, strictly,

modified antennfe . Next come two maxillary
palpi (fig. 7 1), which do not differ in struc-
ture from the legs, except in their tarsi
being composed of a single joint, generally
terminated in the females by a small hook,
but in the males of more complicated struc-
ture : the basal joints of these palpi are
enlarged and project forward, forming the
maxillae (fig. id); these are stated to con-
tain certain glands, opening on the inner
side. of the upper face. In the scorpions,
the mandibles and maxillary palpi terminate
in pincers or forceps. Lastly a labium,
situated between the niaxillse (fig. 7 e), and
consisting of a single piece.

The mouth in the other families is de-
scribed under the respective heads.

The eyes are simple (ocelli, .stemmata),
but they are absent in the parasitic Acarina ;
they consist of a simple arched cornea, a
spherical lens and a concavo-convex vitreous
body, with a cup-shaped retina, and a layer
of pigment corresponding to the choroid.

The cephalothorax is usually separated
from the abdomen by a well-marked con-
striction ; but sometimes the head, thorax,
and abdomen are fused together.

The legs of the Arachnida, which are
attached to the cephalothorax, do not co-
incide exactly with those of insects. They
usually consist of seven segments tapering
towards the end, so that the tarsi are less
distinct from the other parts than in insects.
If we suppose that the last two joints belong
to the tarsus, the tibia then consists of two
joints, of which, in some (the scorpion and
Phrifnus) the first, in others the second, is
the longest. The preceding long joint is the
femur, next to which comes an annular or
inverted conical joint, corresponding to the
trochanter of the six-footed insects. The
first, broad, usually inversely conical joint,
which is adherent to the cephalothorax, cor-
responds to the coxa of insects. The last
joint of the tarsus usually supports three
curved hooks or claws (PI. G. fig. 8), which
are frequently toothed on the concave mar-
gin, and in some a membranous vesicular
or hairy cushion (pulviilus) on its under
side. The most characteristic feature of the
Arachnida consists in the division of the
tibia into two unequal pieces.

The first pair of legs is supposed to repre-
sent the labial palpi of insects.

The alinienfari/ canal is mostly short and
straight. In the Arauere the oesophagus
enlarges into a prismatic muscular expan-
sion just before its termination in the sto-
»

ARACHNIDA.

[ 67 ]

ARACHNIDA.

mach ; tbe stomach splits j ust behind the
above apparatus into two branches, which
curve forwards and form a ring, from which
five pairs of diverticula pass to the roots of
the legs and palpi.

Salivary glands are present, consisting in
the Aranere of a transparent glandular mass
situated in a cavity above the palate ; also a
hepatic apparatus, in the form of a compact
mass, consisting of a number of ramified and
closely-crowded ca?ca, containiugthe hepatic
cells and opening at about the middle of the
alimentary canal in four short ducts. This
hepatic apparatus was formerly mistaken for
the fat-body. In the Tardigrada, Acarina,
and some others the liver is represented by
the granule-cells, usuallj'^ brownish yellow,
of the walls of the diverticula of the stomach.

The poison-glands of the Araneaj consist
of two long, sometimes slightly curved blind
sacs, the walls of which are surrounded by
a simple spiral layer of muscular fibres.

Circulatory S;/sfem. — In the loAver Arach-
nida, as the Tardigrada, Acarina, &c., there
is neither dorsal vessel nor blood-vessels.
Hence in these there is no regidar circulation
of blood, but the nutritive fluid or the blood
is distributed free in the interstices of the
body, and is irregularly moved backwards
and forwards, propelled in the cavity of the
body, and into the extremities, by muscular
movemeuts and the contractions of the in-
testinal canal.

In the Araneoe there is a dorsal vessel
consisting of a spindle-shaped tube lying
principnlly in the abdomen, constricted at
intervals and furnished with lateral apertures
and valves. This heart sends off lateral and
terminal arterial branches, which gradually
become lost. There are no veins ; but the
further course of the blood takes the form
of lacunal currents, which re-enter the heart
at the valvular orifices.

In the scorpions, there are veins as well
as arteries.

Respiratory System. — In the Tardigrada
and some parasitic Arachnida, Demodex,
Sarcoptes, Acariis, &c., no trachea} or other
respiratory organs have yet been discovered ;
hence the respu-ation must be cutaneous. The
higher Ai'achnida breathe either by trachege
(many Acarina), or by lungs, or by both.

Thetrachefe of the Acarina are remarkably
delicate, so that the spiral fibre is with great
difhculty distinguishable. They arise usually
in an unramitied bundle from two stigmata,
which are sometimes situated anteriorly, be-
tween the front legs, as in the Hydrac'hnea,

and mucli concealed, at others at the sides
of the body above the tliivd pair of feet, as
in the Gamaseoe, or behind the last pair, as
in the Ixodeae. They are usually more
tufted than branched as in insects.

In the Ilydrachnea, which live in the wa-
ter, and do not rise to the surface to respire,
the tracheas must possess the power of ab-
sorbing the air from the water. In the
Araneaj, the lungs consist of rounded sacs
situated at the anterior part of the under
surface of the abdomen, and open externally
by a transverse slit. At the outer convex
surface of each lung-sac there are a number
of thin but firm triangular or rhomboidal
plates, like the leaves of a book, closed to-
gether (PI. 6. fig. 9). When examined by
refiected light, they present a silvery lustre ;
whilst by transmitted light they appear dark
violet or almost black. Each of these plates
consists of a fold of the skin, between which
the air of the sac is widely distributed : they
contain on blood-vessels ; hence probably the
blood brought by the arteries is poured out
around the lungs, and so bathes the lung-
plates. The position of the lung-sacs is in-
dicated externally by a triangular and horny
cutaneous plate, at the posterior margin of
which the respiratory fissure exists. Behind
these fissures there are two other openings,
the orifices of a tracheary system which
does not difi'er materially from that of such
as have tracheae only.

Nervous System. — Varies in degree of
complexity. In its simplest form it exists^
as a single oesophageal ganglion, sending off"
radiating branches ; and in its most compound
forms it presents a large cephalothoracic
bilobed ganglion, and one or two ventral
ganglial chains or cords.

The primitive nervous fibres and gan-
glion-cells are very small and delicate.

Spinning-orr/ans. — These organs, by means
of which the Araneida form their webs, are
of great interest. The external organs con-
sist of three or rarely two pairs of cones or
conical papillie, or spinnerets, placed at the
end of tlie abdomen, below the anus : they
are somewhat flattened at the summit; and
usually the middle pair consist of two joints,
and the anterior and posterior pairs of three
joints. The sides ot the cones are covered
with hairs; and on the summits are a number
of delicate horny spinning-tubes, at first sight
closely resembling hairs ; these form con-
tinuations of the spinning-vessels. Some-
times, however, the lower portionsof the sides
of the cones are furnished with spinning-

p2

AEACHXIDA.

[ 68 ]

AEACIJKEDA.

tiiVx^p, the reinaiuder being covered with
hairs. Each spinning-tube consists of two
parts : — a thicker basal portion ; and a thin
terminal portion, from the orifice of which
the substance of the fibre exudes (PI. 6. fig.
10, 10 «, separate tubes). The number of
these spinning-tubes vai'ies according to the
species, the sex, and the age of the spiders.
In some there are more than 1000, in others
400, 300, 100, &c., and in others still fewer.
The glands which secrete the tenacious
transparent secretion are very variable in
number, fiirm, and arrangement, and occupy
the interstices of the other abdominal ■vis-
cera, consist of sacs and tubes, lined with nu-
cleated cells, and either simple or variously
ramified, terminating in ducts which open
at the roots of the spinning-tubes.

The filaments of which the webs of many
spiders are composed are not all alike. The
radiating filaments are but little elastic, and
are composed simply of one or more threads;
whilst the more numerous (tangential) fila-
ments connecting these are covered at tole-
rably regular intervals with minute spherical
masses of glutinous matter (PI. 6. fig. 11),
the filaments themselves being highly elas-
tic. These masses give the fibres an elegant
beaded appearance under low powers of the
microscope. The viscid masses cause the
more ready adhesion of the filaments to in-
sects which may accidentally become en-
tangled in them, and render the spider more
sure of holding liis prey.

Propagation. — The Araclmida generally
are propagated by sexes. The sexual appara-
tus consists of two ovarian or seminal sacs,
sometimes fused together in the middle line ;
they are situated in the abdomen, and termi-
nate in two excretory ducts, which usually
open at a common orifice placed at the base
of the abdomen, or below the cephalothorax.
A penis is not generally present ; theseminal
fluid is applied to the vulva of the female
by the maxillary palpi of the male.
Parthenogenesis has been observed in
Acarina.

Spiders are oviparous : the eggs are en-
veloped in a cocoon, and are often elegantly
sculptured.

There is no metamorphosis, but repeated
erdysis.

The Arachnida may be thus subdivided : —
Order 1. Arankida. Cephalothorax con-
stricted from the unj oiuted abdomen ;
palpi unarmed.
Order 2. PEDiPALn (Phrynida). Cepha-
lothorax distinct from the jointed abdo-

men ; palpi large, leg-like, chelate at the
end. (Pulmonary sacs present.)
Order 3. SoLiFrG.i (Solpugida). Cepha-
lothorax distinct from the jointed abdo-
men; palpi fihfurm, extended, as long as
the legs, unarmed.
Order 4. Pseudoscorpioxes (Obisida) ;
Book-scorpions. Cephalothorax distinct
from the ringed abdomen ; palpi large,
chelate. (Tracheae only present.)
Order 5. Phalangita (Opilionina) ; Har-
vest-spiders. Cephalothorax distinct from
the annulate or transversely plicate abdo-
men ; palpi simple, filiform ; mandibles
chelate ; legs very long, terminated b}' a
single claAv.
Order 6. Acarina (Mites). Head, thorax,
and abdomen fused together; legs di-
stinctly jointed ; palpi simple.

Fam. 1. Acarea. Head terminated in
front by an eraarginate labrum, or single
bifid process ; palpi adnate or adherent to
the labium, difficultly distinguished ;
mandibles chelate ; no distinct ocelli ;
legs generally terminated by a vesicle or
adhesive acetabulum and claAvs.

Fam. 2. Oribatea (Beetle-mites). Body
covered by a hard horny envelope ; man-
dibles chelate ; palpi fusiform, 6-joiuted;
legs furnished with claws, but no vesicle
or acetabulum.

Most of the species live in mosses at
the roots of trees ; in some the body is sur-
rounded bya projectinglamella on each side.

Fam. 3. Ixodea (Ticks). Palpi canali-
culate, sheathing the rostrum ; mandibles
tluee-jointed, basal joint internal, second
joint external and long, third short and
denticulate ; labium covered with reflexed
teeth. (Parasitic.)

Fami. 4. Gamasea (Insect-mites).
Palpi free, filiform ; mandibles chelate ;
feet with two claws ajid a carimcle, or a
lobed membranous appendage; ocelli none
or indistinct. (Generally parasitic.)

Fam. 5.' Ilydrachnea (Water-mites).
Palpi with the last joint unguiculate or
spinous ; two or four distinct ocelli ; coxjb
broad, legs generally ciliated, natatory,
the posterior longest. (Aquatic.)

Fam.d Bdellea (Snouted mites). Palpi
antenniform ; mandibles terminating in
claws or pincers ; rostrum resembling an
elongated head ; body generally divided
between the second and third pairs of legs
by a transA^erse fiu-row or stricture.

The species are minute, more or less
soft, variously coloured, and living in
»

AEACIINIDA.

[ GO ] ARACHNOID MExMBRANE.

damp places beneath moss, upon sand of
caves, &c.

Fam. 7. Trombidiua (Harvest-mites).
Palpi with the last joint obtuse, the
second joint very large ; the last but
one (penultimate) resembhng an incur-
vated claw ; feet cursorial, terminated by
two claws.

Fam. 8. Hypoderidae (Subcutaneous
mites). Oval-oblong, almost transparent
sacs ; the anterior and posterior pairs of
legs widely apart ; tarsi terminated by two
fine hairs.

The species are found in the subcu-
taneous tissue of birds.

Fam. 9. Phytoptidte (Gall-mites).
Legs four, the hinder pairs replaced by
tubercles or hairs.

In the galls and buds of plants.
Order 7. Tardigeada (Colopoda) ; Water-
bears. Legs rudimentar}^, very short,
conical, indistinctly three-jointed, and
with three or four claws ; abdomen not
distinct from the thorax. (Aquatic.)
Order 8. Pycnogonida (Polygonopoda) ;
Crab-spiders. Cephalothorax forming a
4-jointed body ; abdomen rudimentary
(small and conical) ; legs as long as or
longer than the body.

Sluggish marine animals, living under
stones, upon marine plants, or parasitic
upon fish and Crustacea.
BiBL. Treviranus, Bau der Arachn. ;
id. Vermischte Se/u-{ft. ^-c. Bd. 1, 1816;
Dufour, An. d. So. phi/sicj. d. Bru.v., iv.-vi. ;
Walckenaer, Hist. nat. d. Ins. Apt., i.-iii. ;
Siebold & Stannius, Lehrb. d. vergl. An. i. ;
Blackwall, Brit. Spiders {Ray Soc.) 1861-4,
and Linn. Tr. xvi. ; Blanchard, Ann. A\ H.
18-"i0, vi. 67 ; and 18-j2, x. loO ; Newport,
Phil. Tr. 1843 ; Koch, Uebersicht 8fc., and
Arachnid. (534 pis.) ; Claparede, Vevol. i^'c.
1863 ; id. Circulation, ^-c, Ann. N. H. 1865,
XV. p. 16; Cambridge, Encxjl. Brit. 1875,
ii ; Jones, An. Kingd. 1870 ; Gegeubaur,
Vergl. Anat. 1878 ; Walker, BrU. Spiders
{Eay Soc. ) ; Murrav, Econ. Ent. p. 33.

ARACHXID'IUM, Hincks.— A genus of
Ctenostomatous Polyzoa (Bryozoa), fam.
Arachnidiidse.

Three British species.
BiBL. Hincks, Poh/zoa, 1880, p. 508.
ARACHNOID MEMBRANE {Tunica
arachnoidea). — Is a delicate transparent
membrane, lying between the cranial dura
mater and the brain, and extending between
the spinal cord and its dura mater so as to
envelope these nervous centres. It does not

dip between the convolutions of the brain,
but enters and lines its ventricles. Its outer
surface is covered by a delicate epithelial
layer ; its inner surface is smooth, but not
covered with epithelium. It is reflected
upon the surface of the dura mater as an
epithelial layer only. It consists principally
of reticulated bundles of connective tissue,
with fibres of elastic tissue coiling around
or pursuing a rectihnear course through
them. In some parts the fibrillse of the
former run parallel without forming bundles,
and contain, as do the bundles, round, elon-
gated, or spindle-shaped nuclei. In others,
connective tissue of a rather homogeneous
appearance here and there forms a coat to the
bundles, or is situated between them.

F"ig. 29 represents two bundles of the
connective tissue of the human arachnoid,
after the addition of acetic acid, showing
the fibres of elastic tissue.

Fig. 29.

Connective and elastic tissue of arachnoid, after treat-
ment with acetic acid. Magnified 350 diameters.

BiBL. Kolliker, Mik. An. ii. : Henle, All-
gem. Anat.

ARACHNOIDIS'CUS, Bailey (Hemi-
ptychus, Ehr.). — A genus of Diatomaceae.

Char. Fiustules adherent, disk-shaped;

ARACHNOSPIS,

[ 70 ]

ARCELLA.

valves plane or slightly convex, with radia-
ting and concentric lines (rows of dots), and
a central pseudo-nodule.

The markings upon the inner valves are
not the same as those upon the outer (or
parent) : hence the mere variations of the
markings are not characteristic ; nor is the
number of rays constant.

A. ornatus, Ehr. Valves very finely gra-
nular ; rays29,equal. In Patagonian guano.

A. Ehrenherfiii, Bail. I'seudo-nodule sur-
rounded by an inner ring of linear radiating
and an outer ring of circular or angular
markings (depressions) ; marine ; breadth
1-200 to 1-60" ; occurs also in guano. (PI.
16. figs. 12 & 1.3, side view.)

A. mdicus (PI. 51. fig. 3). J &^^\^ ^^

^ • 7 • /-m '1 £ <\ <iNicobar
A. mcobaricus (PI. ol. hg. 4). j, i

BiBL. Ehr. Be): d. Berl. Ak. 1848 &
1849 ; Smith, Br. Diat. i. p. 25 ; Shadbolt,
TV. Mic. Soe. iii. ; Arnott, Micr. Jn. 1858,
p. 159 ; Greville, Micr. Tr. 1865, p. 47.

ARA.CHN0S'P1S, Kent.— A genus of
Infusoria, fam. Halteriidas.

BiBL. Kent, Infus. p. 214.

ARACHNU'LA, Cieuk.— A genus of
Rhizopoda.

Char. Naked, colom-less, without nucleus ;
one or more contractile vesicles ; pseudo-
podia branched, very slender, anastomosing;
bodies connected by thickish cords. Move-
ment active.

A. impatiens. In brackish water. Black
Sea.

BiBL, Cienkowski, ScJi. Arch., 1876, xii.
p. 27.

ARANE'IDA.— A family of Arachnida,
comprising the true spiders.

The species of genera belonging to this
family ( as A. civilis and domestica, house-
spiders, Epeira diadema, garden-spiders &c.)
are readily accessible for examining the
structural peculiarities of spiders — the skin,
the eyes, the organs of the mouth, the max-
illarv palpi, the spinnerets, the legs, &c.
(See PL 0.)

BiBL.Walcken., ^p^eres, i.; \\oc\\, Arachn.
viii. ; Treviranus, Bau d. Arachn. ; Walker,
Brit. Spiders ; JNIurray, Ec. Ent. p. 43.

ARAUC A'RI A, Jussieu.— A genus of Co-
niferse (Gymnospermous Flowering Plants),
remarkable for the character of the markings
on the walls of the cells of the wood, where
the pits or bordered pores appear in two or
more parallel rows (PI. 48. fig. 5). Arau-
earia {Eufassa) exceha is the Norfolk- Island
Pine, which grows to an immense size, as

do also A. hrasiliensis, A. imhricata, &c.
The reservoirs of turpentine seem to be in
the bark and not in the wood. See Coni-
fer.^, Wood, and Secondary Layers.

ARAUC ARI'TES, Goeppert (Dado.vylon,
Endlicher ; Pinites, Lindl. and Hutt.). — A
genus of Fossil Coniferae, characterized by
a structure resembling that of Araucaria.

BiBL. Witham, Fossil Vef/elahles, p. 72,
pi. 4-11. Edinb. 18.33 ; Lindley aud Huttou,
Fossil Flora, l.t. 2,3.

ARCEL'LA, Ehr.— A genus of Rhizo-
poda, of the family Arcellina.

The Arcellfe correspond to Amoebae con-
tained in a carapace. In some species the
carapace is membranous and uniform ; in
others it is calcareous and exhibits fine striae,
depressions, or granides spirally arranged.

A. vidgaris (PI. 30. fig. 14a). Carapace
brownish yellow, plano-convex, or hemi-
spherical, covered with depressions. These
markings or depressions are very beautiful
and interesting. They agi-ee with those
upon the valves of the Diatomaceae in re-
gard to the requirements for their display ;
with unilateral oblique light, lines only are
visible. Their true structure resembles that
in PL 15. fig. 41, or PL 17. fig. 29, except
that the rows are somewhat wa'vy or even
spiral. Fr. wat. ; breadth 1-500 to 1-200".
In the young state it is very transparent and
pale,'and the markings are with diiliculty di-
stinguished. The shell is cast several times
before arriving af maturity. PL 32. fig. 24
represents the animal with its processes pro-
truding from the carapace.

We have seen two of these animals con-
jugating, and so firmly united by the soft
internal substance, that they were not sepa-
rable by rolling them over between two
plates of glass.

A. (Ec/iitiopi/xis) acvleata (PL 30. fig.
14 Z>). Carapace brownish, discoidal, con-
vex above, with one or more irregular spi-
nous prolongations at the margin ; fr. wat. ;
breadth 1-200" without the spines.

A. dentata (PL 30. fig. 14 c). Hemi-
spherical, anguloso-polygonal ; carapace
membranous, homogeneous, vollowish or
greenish ; fr. wat. ; breadth 1-560 to 1-200".

A. aureola (Ci/phidixin auroleum, Ehr.)
(PL 30. f. 38). C'arapace yellow, angular,
with numerous tubercles, four of which are
larger and more projecting ; a single expan-
sion of varied size ; breadth 1-560 to l-420"j
fr. wat. Fig. 38 a represents the carapace
viewed from above, b the same supported
upon one angle, and t\ie single expansion.

AECELLINA.

[ "1 ]

ARCYRIA.

A. arenaria \ in sand, under moss and
lichens. Otiier species.

BiBL. Elirenberg, Infus. ; Chiparede
and Lacliniann, Infiis. p. 444 ; Biitsclili,
Schultzes Arch. xn. 459 (pi.).

ARCELLl'NA, Elir.— A family of Lo-
bose Rhizopoda.

Cltar, Animals contained in a univalve
membranous or solid inflexible carapace,
of an urceolate or shield-like form, with a
sinp-le orifice from which one or more irre-
gular and variable expansions are protruded,
which form the organs of locomotion.

Biitschli describes conjugation ; but the
result is doubtful.

The substance of the body resembles that
of an Amoeba. Gen, : —

Shell flexible, dorsal... Pseudochlamys.

Shell flexible, universal Ampkizonella.

Shell solid, inflexible.

Not incrnsted with foreign matters. Arcella.
Incrusted with agglutinated fo-
reign matters.

With tubular prolongations Echinopyxis.

Without tubular prolongations... Difflugia.

ARCH^DIS'CUS, Brady.— A small,
lenticular, asymmetrical, hyaline Fora-
miuifer, of the Nummuline type ; found in
the Carbonifei'ous Limestone.

BiBL. Bradv, Ann. N. H. 1873, xii. 286.

ARCHEGd'NIUM. Also called ;j2s<«7/«-
dium. — The rudimentary organ representing
the ovule in the higher Flowerless Plants,
such as Mosses, Ferns, &c. (excluding the
Thallophytes). These organs are more mi-
nutely described under the heads of the
various Classes, in speaking of their repro-
duction.

In the Mosses and Liverworts they are
flask-like cellular bodies, found in terminal

Fig. 30.

Fig. 31.

Archegonia of ^VTosses.
Magnified 50 diameters.

or axillary buds on the leafy stems (figs. 30
& 31). In the Ferns and Equiseta they are
produced on the prothallium, after the ger-

mination of the spores. In the Lycopodi-
ace;e and Marsileacepe they are produced
upon the cellular plate, representing a pro-
thallium, developed in the large spores when
these begin to germinate. The corpusctda of
the Ooniferse are analogous bodies to the last.

SeeHEPATICACE..E,MuSCACE^,FlLICACE^,
EQUISETACEiE, LYCOPODIACEiE, MaRSILE-

ACEJE ; also Conifer.^ and Ch.a.iiace.e.

ARCHID'IUM,Bridel.— Ag•enusofPhas-
cace^e(Acrocal'pousMosses), of which but one
species is found in Europe (A. j}/iascoides=
Phascum alternifoUum, Hook, and T. ), grow-
ing upon banks and fallow ground, on clay
or chalky soil. It is remarkable for the
sessile globular capsule, without a trace of
an operculum, the columella soon oblite-
rated, and the spores being few in number,
very large and angular in form (figs. 32 &

Fig. 82.

Fig. 33.

Archidium.

Open capsules devoid of columella and with large

spores. Magnified -10 diameters.

33). The calyptra is torn away in the mid-
dle during the expansion of the capsule, as in
Sj)/>af/tium, leaving a short tumid vaginula.

BiBL. Wilson, Bn/ol. Brit. p. 24.

ARCTO'A, Br. and Sch. = lJicRAXTJM.

ARCYRTA, Hill.— A genus of Myxo-
mycetes, growing on rotten wood, with fre-
quently bright-coloured spores and fila-
ments. The elastic filaments of the capil-
litium have no spiral fibres, but are a little
tuberculated. The species in general are
not confined to Europe or the United States,
but have a very wide geographical range,
occurring in tropical and subtropical dis-
tricts as well as in those which ai'e tem-
perate. Species : —

A. punicea, Pers. Common ; spores and
capillitium purpli.sli vermilion. A dark form
is separated by Rostafinski as A. ferru~
ginea. Grev. Sc. Crypt, Fl. t. 130.

A. incarnate^ Pers. Not uncommon ;
smaller, with a shorter stipes and with flesh-
coloured spores and capillitium.

A. cinerea, Bull. Spores and capillitium
cinereous.

A, nutans, Bull. Spores and capillitium
dirty-yellow ; capillitiiun nodding. Trichia

ARECA.

[ 72 ]

ARKENURUS.

nutans, Sowerby ,t. 260 ; Arcyriajlava, Grev.
Sc. Cnipf. Fl. t. 309.

A. umhrina, Sclium. Spores and capilli-
tium ochraceous, capillitium erect; peri-
diuin ovate.

A. ochroleuca, Fr. Spores and capilli-
tium pale-ochraceous, peridium globose,
evanescent ; smaller than the preceding ;
1-12" high.

BiBL. Berk. Hooke>-''s Brit. Fl. ii. pt. 2.
p. 318; Crypt. Bot. p. 337 ; Fries, Summa
Veget. p. 45G ; Rost. Sluzowce ; Cooke,
3Iy,:

ARE'CAjL.— A genus of flowering plants
(Earn. Palmaceag). The albumen of the seed
of the Areca catechu (the Areca nut, as it is
called) atfords a good instance of horny con-
sistence produced by secoudarv lavers upon
the cell-walls (PI. '^^^. figs. 21^ & 22). See
Albumen (of seeds).

AREGr'MA, Fries. — A genus of Couio-
mycetous Fungi closely allied to Puccinia,
comprising the species with many cells
which occur on various Rosaceie, as the
common dark parasite of the Rose and
Bramble. Like Puccinia, the species always
seem connected with a Uredinous form, and
are propagated by secondary spores pro-
duced on the multiseptate bodies after ger-
minating.

BiBL. Fries, Summa Veg. p. 507 ; Berk.
Crypt. Bot. p. 325 ; Tidasne, Ann. d. Sc. Nat.
1847, Jan. p. 12 ; De Bary, Ueb. d. Brand-

ARE'OLAR TISSUE of animals. See
Connective Tis.sue.

AR'GAS, Walck. — A genus of Arachnida,
of the order Acarina and family Ixodea.

Char. Rostrum inferior, concealed, as also
the palpi, beneath a projection of the ante-
rior part of the body ; under part of body
granular, not scaly, and consisting of a single
piece; first joint of the palpi longest; legs
approximate at their insertion, feet termi-
nated by two claws, but no vesicle.

These animals are frequently parasitic
upon pigeons, fowls, &c. ; some live in
gardens.

A.reflexus{ Wiynchoprion OJnmbcsJ lerm. ) .
Body marked witli tortuous furrows and de-
pressions, yellowish or violet after food. On
pigeons, especially when young.

A. persiciis. Blood-red colour, back co-
vered with scattered elevated white spots.
The venomous bug of Persia ; said to cause
death in the human subject.

There are other species.

BiBL. Gervais, Walcken. Aptcres, iii. ;

Murray, Ec. Entom. 180 (figs of all species) ;
jMegnin, Paras. 1880, 133.

AR'GULUS, Miill. — A genus of Crusta-
cea, of the order Sipbonostoma and family
Argulidffi.

Cliar. Carapace membranous, covering
the cephalothorax like a shield ; antennae
four, short, concealed beneath the carapace,
anterior two-jointed, terminal joint hooked ;
posterior four-jointed; rostrum acuminate ;
five pairs of legs, the place of the first (6th)
pair being occupied by two suckers ; second
pair short, five jointed, the two basal joints
spinous, the last joint with two small hooks ;
the last four pairs of legs two-cleft, and
furnished with ciliated filiform processes.

A.foliaceiis (PI. 20. fig. 1). Parasitic on
the stickleback [G aster osteus) and other
fishes ; carapace greenish.

BiBL. V. d. Ilueven, Zod. ; Baird, Brit.
Entom. p. 2-42 ; Thorell, Ann. N. H. 1866,
xviii. p. 149.

ARPAC'TICUS, Baird.— A genus of
Entomostraca, of the order Oopepoda and
family Cyclopidte.

Char. Head undistiugiushable from tho-
rax ; foot-jaws two pairs, forming strong
cheliform hands; antennae in male furnished
with a swollen hinge-like joint ; antennules
(inferior antennae) simple; legs five pairs,
the fifth pair rudimentary; eye single; ovary
single. Two species : —

A. chelifer and A. nobilis. Marine, closely
resembling Cyclops.

BiBL. Baird, Brit. Entom. p. 212.

ARRENU'RUS, Duges.— A genus of
Arachnida, of the order Acarina and family
Hydrachnea ( = Caudate Hydrachnaj).

The posterior part of the body of the male
is narrowed and produced into a truncate or
cylindrical appendage. The body of the fe-
male is truncated posteriorly. The prolon-
gation is terminated by two angles and a
sinuous intervening margin. At the middle
of the latter is situated the penis ; above
which are two hooks. In both sexes the
back is hard, crustaceous, as if shagreened,
or spinous. In some species the thicker
layer of the skin is furnished with a number
of conical apertures (PI. 0. fig. 12). The
eyes are two, distinct, blackish. The intes-
tinal caeca are distinguishable through the
skin. The mouth is round and surroimded
by a kind of hood (PI. 6. fig. 13, c).

Arrenuriis viridis, Duges 's typical species
(PL 6. fig. 13), has the palpi short and cla-
vate (a); the fourth joint longest and largest,
the fifth falcate, and the mandibles ung-ui-

AE ROW-ROOT.

[ 73 ]

ARTERIES.

culate (b). According to Murray, this is the
male of Ata.v histrionicus !

The species are very numerous and of almost

all colours — red, green, yellow, grey, purple.

BiBL. Walckeu. Apt'eres, iii.; Duges, Ann.

d. Sc. N. 2 ser. i. ; Koch, Ueberskht ij-c. 5

Murray, Ec. Ent. p. 154.

ARROW-ROOT.— A name given to va-
rious kinds of starch, derived from the plant
Maranta arundhiacea and other species.
True West-India arrow-root is from this
(PI. 46. fig. 26j and M. allonya and M. no-
bilis (N. O. Marautacece). East-India arrow-
root is ohtained from species of Curcuma
(N. O. Zingiberaceaj) (PI. 46. fig. 19), and
apparently also from a Sagus, if we may j udge
from a specimen (PI. 46. fig. 18) from Singa-
pore. Tahitan arrow-root (PL 46. fig. 22) is
obtained fi'om the plant called Tacca pinna-
tifda (N. O. TaccaceEB) ; and the substance
called Portland arrow-root (PI. 46. tig. 11)
is extracted from the Arum macidatum (N.
O. Araceae), a common hedge-weed in this
country. In all these cases the fecula con-
sists of starch-grains, which are produced in
great quantity before the season of rest, in
the succulent tubers or rhizomes of the
plants; the arrow-root is extracted from the
grated root-stalks by washing, to separate
the cellular tissue and remove the often
acrid juices. See Starch.

The arrow-root of the shops is subject to
adulteration with cheaper kinds of starch,
especially with sago and potato-starch.

BiBL. Pereira, Mat. 3Ied. ; Hassall, Food
and its Adulterations, p. 31.

ARSENIC. — The common term for arse-
nious acid. Arsenious acid assumes two
crystalline forms, and occurs also in an
amorphous state.

The most common form is the octahedral
or tetrahedral. The second (right rhombic)
is less common, and is only obtained by
sublimation, .\ttention to the form of the
crystals is important, because it is used as
a means of identifying arsenic in cases of
poisoning. It must, however, be borne in
mind that protoxide of antimony (Sb O3)
yields crystals by sublimation of exactly
the same form as those of arsenious acid
(PI. 10. fig. 22).

Solution of arsenious acid is sometimes
\ised as a preservative liquid for animal
preparations.

BiBL. Guy, Mic. Tr. 1861, p. 54.
ARTE'MIA, Leach. — A genus of Ento-
mostraca, of the order Phyllopoda and fa-
mily Branchiopoda.

Char, Abdomen prolonged in the form of a
tail, composed of nine segments or joints, the
end joint simply divided into two lobes ;
superior antennte slender and filiform in both
sexes ; inferior antennae in the male large,
flat, curved downwards and two-jointed, re-
sembling horns 5 in the female short, pointed
and slightly curved ; basal joint of male
inferior antennae provided with a short coni-
cal process.

A. salina. The Lyminglon shrimp or
brine-worm. Found in the salt-pans at
Lymingtun. Length about 1-2".

Each segment of the thorax shortly bi-
lobed at the apex, and with a pair of bran-
chial feet; each lobe of the end joint of abdo-
men giving ofip several short setae. Agrees
generally in structure ^^ ith Branchipus.

BiBL. Baird, Brit. Entom. ; Rackett,
Linn. Tr. xi.

ARTERIES.— These are the tubes or
vessels which convey the blood from the
heart to the various parts of the body. The
structure of the arteries is very complicated
and difiicult of investigation; and the coats
or timics of which they consist are so inti-
mately connected as to be by no means
easily separable.

In the larger arteries, three coats are
usually distinguishable, an outer or adven-
titious coat, a middle, and an inner coat or
intima, with its epithelial Huing. Their
composition and thickness vary in arteries
of different sizes.

The general character of the arteries is
that the middle coat is thick and strong,
consisting of several layers, and its elements
run transversely. In the largest arteries it
is yellow, very elastic and of great strength ;
as the vessels become smaller, it diminishes
in thickness, becoming redder and more
contractile ; and near the capillaries it is very
thin, finally disappearing. The inner coat
is always thin, yet thickest in the large ves-
sels ; whilst the outer coat is absolutely
thinner in these than in those of a moderate
size, in which it equals or even exceeds the
middle coat.

In the small arteries the epithelial lining
consists of very delicate pale, flattened, fusi-
form cells with longish oval nuclei.

An elastic layer is expanded beneath the
epithelial layer, which is smooth in the
living vessels, whilst in these, when empty,
it exhibits numerous transverse or longitu-
dinal folds. It forms what is called a fenes-
trated membrane, generally exhibiting more
or less distinct reticulated fibres, and usually

ARTERIES.

[ 74 ]

ARTERIES.

small elongated openings ; more rarely a
very dense network of principally longitudi-

34.

Fig.

Magnified 3.50 diami ters.
^A small artery (a) and Tein (J) (about 1-lSO" in diameter) from the me-
sentery of a child, after the addition of acetic acid : a, exfernal coat, with
elongated nuclei ; /3, nuclei of the muscular fibres of the middle coat, partly
seen from the surface, partly the sectional view ; y, nuclei of the epithelial
cells ; S, fibrous layer of elastic tissue.

nal elastic fibres, with narrow
fissures.

Flo-. .35.

elongated

Magnified 350 diameters.
Muscular fibre-cells from human arteries. 1, from
the popliteal ; a, before, b, after the addition of acetic
acid; 2, from a twig of the anterior tibial artery: a,
nuclei.

The middle coat of the smaller arteries is
purely muscular. The fibres or fibre-cells,
W'hich are transverse and
connected into layers, may
be isolated by dissection,
or by maceration and boil-
ing in a mixture of nitric
acid with four parts of
water.

The outer coat consists
of connective tissue with
elongated nuclei and fine
elastic fibres, and is nearly
as thick as, or even thicker
than the middle coat.

In the smallest arteries,
the outer coat gradually
ceases to contain elastic
tissue, consisting merely of
areolar tissue and the nu-
clei ; this gradually loses
its fibrous character, next
becoming homogeneous,
and finally a thin perfectly
structureless membrane,
and disappearing. In the
same manner the middle
coat gradually loses its lay-
ers of muscular fibres, until
these and the fibres them-
selves ultimately vanish.
On tracing the smaller
arteries downwards, the inner coat is first
found to lose its' elastic fibres ; and at last
the epithelial cells cease to be isolable, all
that can be distinguished consisting of their
closely aggregated nuclei ; but by macera-
tion in very dilute solution of nitrate of sil-
ver, the lines of demarcation of the cell-
walls are rendered beautifully distinct.

In 7no(h'ratc-sized avtevies the middle coat
increases in thickness, but, in addition to a
larger number of muscular layers, fine elas-
tic fibres in open networks are added, at
first running somewhat irregularly through
the muscular elements, and in the larger
vessels of this category mixed with areolar
tissue and here and there forming layers
alternating with those of the muscular fi-
bres. The inner coat sometimes contains
between its elastic layer and the epithelium
several other layers, forming, with fine net-
works of elastic tissue more externally
situated in homogeneous granular or fibrillar
areolar tissue, a strong middle layer, the
elements of. which are longitudinal. The
outer coat in these vessels contains more
elastic tissue, in the fqi-m of laminte.

ARTERIES.

[ 75 ]

ARTIIROBOTRYS.

In the largest arteries, the epithelial cells
of the inner coat are not so elongated, and
the inner coat consists principally of layers
of a homofyeneous, striated, or even di-
stinctly tibrillar substance, agreeing with
areolar tissue, traversed by finer and coarser
longitudinal networks of elastic tissue. Im-
mediately beneath the epithelium the net-
works or elastic fibres are either very fine,
or are replaced by one or more striated
layers, vrhich, when nucleated, often appear
as if composed of fused epithelial cells, and
Avhen homogeneous resemble pale elastic
membranes. The middle coat contains, as
a new element, elastic membranes or plates,
as many as 50 or GO, which, except in their
transverse direction, resemble the elastic
inner coat, sometimes forming the densest
networks of elastic fibres, at others fenes-
trated membranes. These layers alternate

Fig. 36.

Magnified 30 diameters.

Transverse section of the human aorta below the superior mesenteric ar-
tery, after acetic acid. 1. Inner c«at: a, epithelium ; 6, striated layers ; c,
elastic layers. 2. Middle coat : d, its elastic layers ; e, the muscular and
areolar tissues. 3. Outer coat with its network of elastic tissue.

with those of the muscular fibres traversed
by areolar tissue and networks of elastic
tissue. The muscular layer of the middle
coat is less developed, its cells smaller and
less regularly and perfectly formed.

The outer coat is relatively and absolutely
thinner than that in the smaller ; but the
structure is the same, except that its inner
elastic layer is much less developed.

In some of the larger arteries of man, as
the axillary and popliteal, and the mesenteric
arteries of other mammals, the internal coat
contains unstriped muscular fibres. This
is the case also with the outer coat of
the larger arteries in animals, but not in
man.

All except the smallest arteries are fur-
nished with nutrient blood-vessels, the vasa
vasorum ; these ramify principally in the
outer

coat, in the larger ones extending into

the middle coat. They also receive branches
of the sympathetic and spinal nerves.

Transverse sections of the arteries are
best made with the freezing section-cutter
or microtome. The epithelial cells require
the use of solution of nitrate of silver.

The most important patliological changes
to which the arteries are subject, consist of
the deposition of fat in their substance
(fatty degeneration) and of atheromatous
matter. These will be noticed under Fatty

DEGENERATION and ATHEROMA. See

Vessels.

BiBL. Heule, Allg. An.; Kolliker, Geive-
helehre ; Wedl, PatJi. Hist. ; Rokitansky,
Krankh. d. Art. ; Frey, Histologie, 1881 ;
Eberth, Strieker's Handlmch, v. p. 190;
Rutherford, Hist. p. 100 ; ColwikQim, Pathol.
1878, p. 1(38.

ARTHO'NIA, Ach.— A genus of Li-
chenaceous Lichens, tribe
Grapliidei.

Char. Thallus thin or
subepidermal and evanes-
cent ; apothecia dark, in-
nately sessile ; asci pyri-
form ; spores 4-8, septate,
upper cell larger ; no para-
physes.

32 species, some common ;
on trees, holly, ash, oak &c.
BiBL. Leighton, Lich.
Flora, 1870, p. 414.

ARTHRIN'IUM, Kze.
• — A genus of Dematiei
(Ilyphomycetous Fungi),
of which one species has
been found in Britain,
growing upon dead leaves of Eriophorum
angustifolium.

A. sporophlceum, Kze.

Filaments elon-
gated, tufted, often not more than 1-50"
long, but frequently confluent in a linear
form, with a kind of velvety surface; spores
numerous,angular, or like a double cone, at-
tached in whorls at the joints of the filaments.

BiBL. BQxk(i\ej,Ann.X.H. 18:i8, i.p. 436 ;
Torula Eriophori, Berk. Enql. FL v. pp. 2,
359 ; Fries, Sum. Veg. p. 502.

ARTIIROBOTRYS, Corda.— A genus
ofMucedines ( Hypho my cetous Fungi) bear-
ing elegant nodular groups of septate spores.
No species is yet recorded in Britain.
Corda describes one species, A. superha (fig,
37) ; in this the spores are about 1-1500"
long. Fresenius describes another, A. oligo-
spora, perhaps not distinct, which has the
erect filaments about 1-50" high, solitary,.

ARTHROBOTRYUM.

[ 76 ]

ARTOTROGUS.

not in tufts, and mostly with only one
group of spores ; these are pear-shaped,
1-700" long, and have the septum below
the middle : it was found on damp wood,
fruit and earth, in a fungus-bed.

Fig. 37.

Fier. 38.

&Yi\

Arthrobotrys superba.

37. Fertile filament with many groups of spores.

Magnified 200 diameters.

38. Fertile articulation of ditto, with most of the

spores detached from the spine-like pro-
cesses on which they are borne. Magnified
400 diameters.

BiBL. Corda, Schimmelb. p. 43, t. 21 ;
Fresenius, Beitr. zur Myc, Heft i. p. 18,
pi. 3. figs. 1-8.

A RTHROBO'TRYUM.— Agenus of Mu-
cedines (Hyphomycetous Fungi), proposed
by Cesati, characterized by a stem composed
of jointed threads, bearing above large
jointed radiating spoi'es, so as to form a
little head. They are beautiful microscopic
objects. British species : —

A. atrum, B. & Br. On dead nettle-
stems.

A. stilhoideum, Ces. On a poUard-willow.

BiBL. Berkeley, Out. Br. Fung. p. 342 ;
Hechvif/ia, tab. 4. fig. 1.

ARTIIROCLA'DIA, Duby.— A genus of
Sporochnacese (Fucoid Algaj). A. villom,
Iluds., is a rather rare Bi itish annual sub-
marine species, growing in 4 to o fathoms
water ; bearing a curious pod-hke nucleated
fruit.

BiBL. Harvev, Brit. Mar. Alga, 2d ed.
p. 24, pL 6C.{ Phyc. Brit. t. Ixiv. ; Eng.
Bot. t. 546 ; Derbes and Sober, yinn. d. 8c.
Nat. 3 ser. xiv. p. 33, figs. 18-20.

ARTIIllODES'MUS, Ehr.— A genus of
Desmidiiiceje.

Char. Cells single, compressed, constricted

in the middle; segTuents entire, with a single
spine on each side.

A. convergens. Segments elliptic (PL 14.
fig. 27) ; length 1-598 to l-53iJ".

A. incus, Breb. Segments with truncated
ends; length 1-1103".

A. minutus, Kiitz. (PL 18. fig. 9).

A. truncatus, Ehr.

A. suhilatus.

Other species.

BiBL. Ralfs, Brit. Desmid. pp. 117, 200 ;
Kiitzing, Sp. Alg. p. 176; Ehrenberg, hifus.
p. 158 ; Rabenhorst, Fl. Alg. iii. p. -I'lo.

ARTHROGY'RA, Ehr. — An obscure
genus of Diatomacete.

A. guafemaknsis (PL 51. fig. 8). Fila-
ment straight.

A. semilunaris. Filament curved. Both
in Guatemala earth.

BiBL. Ehrenbero-, Mikrogeolo(/ie, pi. 33.

ARTHROM'ITUS, Leidy.— Described as
a genus of the Leptothriceee of Kiitzing
(Algaj Confervoidese). Two species, A. cris-
tatus and A. nitidus, were found in the in-
testinal canal of lulus marginatus, a kind of
millipede. These objects appear to have
been imperfect forms of some filamentous
Fungus. See Parasites.

BiRL. Leidv, Proc. Ac. Philadelphia, iv.
p. 225, 1849 (Aiiti. N. H. 2ud ser. v. p. 74).

ARTHROXE'MA, HassalL— A genus of
Oscillatoriacese (Confervoid Algae).

A. cirrhosum (PL 8. fi^. 20), Filaments
of considerable- size, striae close, evident.
Tufts widely spreading, filaments floating
in bundles. In lakes at Lismore Island.

BiBL. KassnW, Brit. Algce, -p. 23S; Raben-
horst, Fl. Alg. ii. p. 2(')7.

ARTHRtiSI'PHON, Kutzing. See Pe-

TALONEMA.

ARTICULI'XA, D'Orb.— Very narrow
varieties of f^ertelralina, which commence
with a Milioloid (Trilocuhna) growth, and
proceed with straiglit moniliform chambers,
were separated by D'Orbigny under this
name. Recent and fossil.

Articulina gihhcrula (PL 23. fig. 9 a h).

BiBL. D'Orbigny, Ann. Se. N. vii. 300 ;
Carpenter, Tntr. For. 73.

ARTOTRO'GUS, Mont.— A genus of Se-
pedoniei (Hyphomycetous Fungi) contain-
ing one species, growing and fructifying in
the intercellular passages of germinating
potatoes. This genus is supposed by Berke-
ley to be founded on a secondary 'form of
fruit of some mould ; probably o'f Perono-
spora infestims. See Peroxospora.

A. hydnosporus, Mont. Berkeley, Jn.

ARTOTROGUS.

[

]

ASCIBICOLA.

Horticult. Sac. i. p. 3, pi. 4. figs. 27-29 ;
Crypt Bot. p. 247 ; De Bary and Wciroiiin,
Beit. iv.

ARTOTRO'GUS, Boeck.— A genus of
Entomostraca, Ord. Copepoda. Four Brilisli
species; marine, living in the brancliial sacs
of Ascidice, or on the integument of marine
Invertebrata.

BiBL. Bradv, Copepoda {Ray Sac.'), iii.
p. 59.

A'RUM, L. — A genus of Aracese (Flow.
PLmts). Anmi maoilatum, the common
Cuclvoo-pint, has a tuberous rhizome in
which is produced much starcli. This starcli
is extracted in the same way as Arrow-root
starch is from the rhizomes of Marantacefe
&c.,and is called Portland Arrow-root (PI.
40. lig. 11). See Staech.

AS'CARTS.— A genus of Entozoa, of the
order Coelelmintha and famil_y Nematoidea.

Char. Body cylindrical, narrowed at each
end ; head furnished with three tubercles or
Aalves : mouth terminal, situated between
the three tubercles ; male with one or two
spicula.

The species are very numerous, occurring
in all the classes of theVertebrata and doubt-
fully in Insects. They are most commonly
found in the alimentary canal. We shall
only notice the species met with in man.

A. Imnhricoides. The common round
worm. Inhabits the human small intes-
tine ; sometimes found also in that of the
ass, wild-boar, pig, and ox. "\'aries in length
from 3 to 15" ; is of a whitish colour ; the
head distinct, with the three valves (PI. 21.
fig. 9) finely denticulated on their inner
border, and each furnished near the summit
with a slightly projecting papilla. Female
larger and more common than the male.
Spicida two, equal.

The recent ova are surrounded by an al-
buminous layer, the surface being studded
with numerous projecting tubercles.

A. vermiadaris {0.vyi(ris verm.). The
human thread-worm. Found usually in the
rectum. White ; head frequently appearing
winged, or exhibiting two lateral vesicular
expansions (PI. 21. fig. 8 a), produced by
endosmosis. Mouth round when contracted,
exhibiting the three lobes when expanded.
CEsophagxis (e) containing a triquetrous
canal, and separated by a constriction from
the spherical stomach (d). Length, female
8 to 4-10 of an inch ; male shorter, with
the tail spirally coiled, much more rarelv
met with. Anus (cf) about 1-8 from the end
of the body ; spicidum single, with an ap-

pendage. Uterus consisting of two lobes
(/() (ovaries); ovidnct (k) opening externally
near the middle of the body.

A. mystax {cilata, Bell), 2 to 3 inches long,
as broad as a crow-quill ; common in the
cat, occasional in the human body.

A. niyrovenosa, with the intestine black,
is found in the lungs of the frog and toad ;
and parthenogenesis is supposed to occur.
The females live in the lungs. The young
pass into damp earth or mud, where they
grow into sexual forms also producing em-
bryos, which do not arrive at sexual matu-
rity until they reach the lungs. No males
are fomid in the lungs.

BiBi.. Dujardin, Hehninthes ; Leuckart,
Menscli. Parasit. ii. p. 153 ; Downe, Mn.
Mic. Jn. 1871 ,T. p. 55 {A. lumbr.) : Cobbold,
Entozoa, 1879, p. 243 ; Duj. Helm. p. 178 ;
Leuckart, Paras., 1879, p. 128.

ASCHEMONEL 'L A, Brady.— One of the
branching Arenaceous Eoraminifera. The
chambers inflated, with 2 or more tubulated
apertures, any of which may produce a new
chamber.

BiBL. H. B. Brady, Qu. Jn. Mic. 1879,
xix. p. 44.

ASCIDIA, B.ist.— A genus of Tunicate
Mollusca, of the family Ascidiadse.

Several British species. See Ascidiad^,

ASCIDTADJi.— A family of Tunicate
Mollusca.

Distinguished by their being single,
usually fixed (to foreign bodies, as sea-
weeds, shells, &c.), and the attachment of
the mantle to the test at the orifices only.

Irregularly shaped, from half to several
inches long, often incrusted with stones and
shells, &c. ; with two orifices, one branchial
and pharyngeal, the other anal. British
genera :

Ascidia, Bast. Test leathery ; branchial
orifice eight-lobed, anal six-lobed, both cir-
cular ; branchial sac not plaited.

Molyula, Forbes. Globose, attached or
free ; test membranous, usually covered with
foreign matters ; branchial orifice six-lobed,
anal four-lobed, both on contractile naked
tubes.

Cynthia, Sav. Sessile ; test leathery ;
branchial sac plaited longitudinally ; both
orifices four-sided. '

BiBL. Forbes and Hanley, Brit. Moll. i.
p. 29 ; Gosse, Mar. Zool. ii. p. 35 ; Pascoe,
Zool. 1880, p. 171.

ASCIDIC'OLA, ThoreU.— A genus of
Entomostraca, Ord. Copepoda. 1 species,
marine.

ASCLEPIADACE^.

[ 78 ]

ASCOMYCETES.

Brady, Copepoda {Ray Soc),

-A genus of Fla-

BlBL.

p. 145.

ASCLEPIADA'CE^.— A family of Di-
cotyledonous flowering plants, presenting
some remarkable characters in the pollen
(see Pollen). The stems of some of these
plants contain very tenacious fibres, which
have been used for economical purposes
(see Fibres, vegetable).

ASCOB'OLUS.— A genus of HelveUacei ;
distinguished from Peziza by the asci being
projected from the hymenium at maturity.
Ascoholus ftirfuraceus is common on cow-
dung ; but there are numerous other British
species. The sporidia are often beautiful
microscopic objects (Cooke, Seemann^s Jn.
Bot., May 1864).

ASCOCOC'CUS, Billr.— A genus (form)
of Coccohacteria fieptica, consisting of very
minute colourless globules, closely united
into globular or oval families, irregularly
lobed, surrounded by a thick gelatinous en-
velope, forming a soft, flocculent, easily
disintegrated membrane. See Coccobac-

TEEIA.

ASCOGLE'NA, Stein.-
gellate Infusoria.

C/utr. Those of Eufflena, enclosed in and
fixed by the base to a flask-shaped lorica.

A. vaf/im'eola. Green, with eye-spot ; in
fresh water.

BiBL. Kent, Inf. p. 393 (fig.).

ASCOMY'CES.— A genus of Ascomy-
cetous Fungi, changed by some botanists,
without reason, into JExoascus, characterized
by the absence of any receptacle, the asci
forming a thin pulverulent stratum. All
the species are parasitic on living leaves or
young shoots. It is the lowest form to
which Ascomycetes can be reduced. British
species :

A. hidlatus. On pear-leaves.

A. (hfonuans. On peach-leaves, produ-
cing a form of blister ; and on young plums,
forming what are called bag-plums, in which
the stone is not developed.

A. trientalis. On leaves of T. europcca.

A. jinjlandis. On walnut-leaves.

A. carnosa. On li/iododcndron ferru-
(fmeiim, producing large gall-like excres-
cences.

BiBL. Berkeley, Jn. Ilort. Soc. vol. ix.
p. 48 ; ])>: Fun//, p. 37G.

ASCOMYCE'TES.— An order of Fungi
characterized by producing the spores in
tubular sacs (asci or thecce), frequently in-
termixed with empty filiform sacs {pnra-
physes) (lig. 40), and hence bearing a near

relation to the Lichens, which, indeed, are
included under this order by some botanists ;
but the existence of green colouring-matter
in the cells, and oi ffunidia or brood-cells, in
the Lichens, forbids such an association.
The Ascomycetes ditFer much in external
form, and approach in this particular several
tribes belonging to the other orders : thus
the Tuberacei are very much like many of
the Gasteromycetes, the HelveUacei like

Fig. 39.

Fig. 40.

Spathulea flayida.

Fig. 39. Entire plant (reduced).

Fig. 40. Highly magnified section of fructifl cation,
showing asci and paraphyses arisingfromthe hymenium.

some Hymenomycetes, &c., differing chiefly
in the mode of the production of the sporidia
(figs. 39-42).

Fig. 41.

Fig. 42.

Leotia geoglossoides.

Fig. 41. Group of planls (reduoedl.

Fig. 42. Highly magnified asci with spores.

The Onygenei are little Fimgi growing on
dead animal substances, feathers, horn. Sec,

ASCOMYCETES.

[ '9 ]

ASCOMYCETES.

and have a flocculent niycelium, bearing
little columnar bodies terminating in a thick-
ened head — the sporange, which is a kind of
hood falling ofl" at matinitv. The sporifcr-
ous structure, loosely filling up the hood, is
composed of interlacing branched filaments,
bearing at their free ends globular cells
(asci or thecce) filled with spores.

The Perisporiacei are likewise very simple,
consisting of parasitical Fungi growing upon
the leaves of trees or herbaceous plants.
They have a flocculent mycelium, often
radiating from a centre, where is found a |
membranous, sac-like, globular conceptacle,
containing sometimes a definite, sometimes
an iudetinite mmiber of clavate sacs or asci,
alone or mingled with paraphyses, and
containing ovate spores. The conceptacle
bursts either regularly or irregularh' at tlie
summit.

The Sphseriacei have the conceptacles
more developed, either single, or associated
on a common receptacle, and consisting of
a firm capsular structure, hued with asci, and
opening at the apex by a regular pore in the
form of a papilla or beak when mature.

The Phacidiacei difler chiefly in the de-
hiscence by slits, either single or longitu-
dinal, or several and parallel or stellate, or
circular so as to detach a lid ; most of these
have the sporanges collected on a common
receptacle, either of horny or fleshy consist-
ence.

In these two families, and in Helvellacei,
Coniomycetous forms of spore are foimd
upon the same receptacle, either contem-
poraneously or at diflerent stages of deve-
lopment. Attention is directed to this sub-
ject under the head of that order ; and more
will be found under Sph^eia, Tympanis,
Ehytisma, Doth idea, Cobdiceps, &c.

The true Tuberacei are Ascomycetous re-
presentatives of the Hypogseous Gasteromy-
cetes, being subterraneous, solid, globidar
or lobed bodies, of fleshy consistence, the
Truffle being a well-known example. The
organization of the Tuberacei is analogous
in all cases, but the structures differently ;
arranged. They all have an inconspicuous
flocculent mycelium, from which arises the
solid sporange. The sporange exhibits, when
cut across, an outer tough coat (peridium),
enclosing a fleshy structm-e excavated with
sinuous cavities giving it a marbled appear-
ance. These sinuous cavities are produced
by the convolutions of the fructifying
layer, which is folded and reflected back-
wards and forwards, leaving interstices

which are lined with the asci or spore-saca
containing four or eight spores. The de-
gree of complexity of the lacunose mass
differs in dift'erent genera, being in some
simple, in others very complicated.

The fructification of the Helvellacei vai'iea
much in form, the simpler resembling
closely some of the Phacidiacei : some kinds
are minute fleshy cups lined with asci form-
ing a superficial layer, as in Propolis ; or
they are large fleshy cups, often raised on a
stalk (Peziza), these cups being closed at
first, but opening widely afterwards. In
the Helvellce, the cup is converted into a
stalked mitre-shaped body clothed above
with asci. Others are of columnar form,
thickened at the summit, which is clothed
with the asci, as if a cup-shaped receptacle
had been turned down over it (Spathulea,
fig. .39 ) — tliis thickened head becoming more
considerable and excavated into little pits in
Morcliella. These plants are mostly found
on the ground or decaying vegetable sub-
stances, in damp places, and are frequently
of gelatinous consistence.

If a Peziza, MorcheUa, Phyfisma aceri-
num, or similar Fungus, in its last stage of
development, is kept shut up in a bottle for
several hours, and then gently taken out,
the contact of the external air causes an im-
mediate and abundant explosion of spores,
which may be collected on slips of glass for
microscopic examination. If care is taken
in the experiment, it will be found that a
considerable quautity of a colourless hquid
is expelled with the spores, which liquid
contains minute molecules, and evaporates
very rapidly, leaving more or less apparent
spots on the glass. See Sph^ria.

Synopsis of the Families.

Helvellacei. Fruit fleshy, of various
forms, ultimately expanded, clavate, capi-
tate, stalked, mitre-shaped, cup-shaped or
beU-shaped, the upper surface clothed by
elongated sacs (asci), each containing eight
simple or septate spores.

Tuberacei. Fruit (subterraneous) glo-
bular, with an adherent peridium ; solid
and fleshy within, and excavated sinuously
into numerous cavities clothed by asci con-
taining fom- or eight spores ; the internal
mass drying up or becoming pidverident or
floccose when mature.

Phacidiacei. Fruit fleshy, simple or
branched, more or less cup-shaped in the
sporiferous region, which opens widely
or by a slit when mature, and exposes a

ASCOPflORA.

[ 80 ]

ASPERGILLUS.

cavity lined with elongated asci mixed with
paraphyses.

Sph^riacei. Fruit usually forming a
common, often horny, receptacle, in which
are excavated conceptacles, lined with asci,
opening by a terminal pore.

Pr.RispORiACEi. Common receptacle floc-
cose, radiating from a centre, bearing con-
ceptacles free or surrounded by filaments,
opening by a terminal pore, with asci at-
tached at the base filled with simple ovate
spores.

Onygenei. Mycelium floccose, bearing
capitate, stalked sporanges, which open
by a circidar slit at the base, causing the
upper part to fall off like a cap ; exposing
a fructifying mass composed of interlacing
branched filaments, bearing globular asci at
the free extremities of the branches.

BiBL. See under the heads of the Families.

ASCOPH'ORA, Tode. See Mucor.

ASCOT'RICHA,Berk.— Agenusof Peri-
sporiacei (Ascomycetous Fungi), containing
one species.

A. chartarum, a kind of mildew growing
on paper, forming a broAvnish, angularly and
dichotomously branched mycelium, from
which arise globose, black, hairy peridia con-,
tainiug linear asci, each containing a single
row of chocolate-coloured spores. Peridia
from 1-20 to 1-30" in diameter.

BiBL. Berkeley, Ann. N. H. 18-38, i. 257,
pi. 7. fig. 8.

AS'CUS. — The term apphed to the cylin-
drical globose or clavate tubnlar sac forming
tlie parent ceU of the sporidia in the Asco-
mycetous Fungi. It is frequently called a
theca also (tigs. 40 and 42). Asci consist
of a double membrane, the inner often
visibly projecting when the ascus is broken
across. A little lid is frequently separated
from the apex when the sporidia are dis-
charged, as in Ascobohis, in which genus
the asci are shot out from the common
hymenium. See Ascomyoetes.

'Bibl. 3/w/. Zord. <^- Bot. vol. ii. p. 222;
Frhu/sh. JaJirb, Bd. i. p. 189 ; Cooke, Hand-
book.

ASEL'LUS, Geoffroy (the water wood-
1 nise). — A genus of fJrustacea, of the family
Isopoda.

(J}ia7\ Antennae four, outer much longer
than the inner ones ; legs shorter than the
body, the first pair not clielate ; two poste-
rior projecting bifurcate abdominal appen-
dages.

A. milgarh (PI. 18. fig. V?,). Length 1-4
to 1-2" or more. This animal is particu-

larly interesting to the microscopist, on ac-
count of its forming the most readily pro-
curable object for examining the dorsal
vessel and circulating liquid in motion. It
is found in almost all stagnant waters. The
currents of the circulating liquid, with
the colourless corpuscles, are readily seen
streaming through every part of the body.
Beneath the large scutiform joint of the
body (the abdomen), are three flattened
branchial false legs or gills on each side,
covered by two jointed gill-covers ; these
are in almost constant motion during life.

BiBL. Desmarest, Consid. Gen. s. I. Criis-
taces ; Treviranus, Vermischte Schriften, i. ;
M. -Edwards, Crustaces, iii. (Suites a Buf-
fon).

ASPERGIL'LUS, Micheli.— A geuus of
Mucedines (Ilyphomycetous Fungi) forming
common mould, such as the blue mould of
cheese, A. glaucus. The chains of spores
arise from a more or less globular head at
the apex of the fertile
filaments (fig. 4.3). It is
often stated that the
heads of spores are origi-
nally enclosed in a peri-
dium ; according to our
observations this is not
the case ; the spores bud
out from the capitular
cell, which enlarges very
much during the forma-
tion of the head of spores.;
and when these have been
detached, the head is left
bare, but covered with
short spiny processes (the
points of attachment of
the chains of spores), and with ciiainsof spores
thenlookssomethmo-like °°,? ^^°v,"^^"\n'''''^-

... r n r M;igniUed 50 dia-

a young periduun of Mii- meters.

co}\ Aspej'ffiUns has been

found to produce a secondary form of fruit,

being that forming the subject of the genus

EuROTiUM. British species :

* Fertile filaments simple.

A. f/lnnofs, Link. Sporidia globose, va-
riable, white to glaucous, close {A. candidi/s,
Link) or lax. Heads about 1-100" in dia-
meter when mature. On cheese, lard, bread,
kc, very common (fig. 43). It has been found
also in the lungs and air-cavities of birds,
Mucor glaucus, L.

A. roseus, Lk. Sporidia globose, very
small, rose-red ; fertile filaments not sep-
tate. On damp paper, lint, carpet, &c.

Aspergillus glaucus.
A fertile filament

ASrEROCOCCUS.

[ ^1 ]

ASPIDISCA.

A. aureusi Berk. Sporidia large, ellipti-
cal, thinly scattered, golden-yellow ; fertile
filaments without septa. On bark. Now
referred with A. mirantiacus, from which
it scarcely diiFers, to the genus Rhinotri-
c/mm.

A. auranfiacus, Berk. Sporidia oval,
the lowest of the chain much larger, myce-
lium rusty orange, the heads often prolife-
rous, so as to produce a complicated mass.
On bark. Ann. X. If. vi. p. 430, pi. xiii.
fig. 22. Nematogonium aurantiacum,
Desmaz. Ann. des Sc. Nat. 2 ser. ii. p. 69,
pi. 2. fig. 1.

** Fertile Jilaments branched.

A. maximus, Lk. Sporidia very large,
at length yellow-brown, mycelium a fleecy
mass of the same colour ; fertile filaments
dichotomous, clavate above. On decaying
Fungi.

A. moUh, Berk. Sporidia large, sub-
globose, white, mycelium white ; fertile
filaments dichotomous, standing in minute,
scattered, white bundles.

A. virens, Lk. Sporidia, like the fila-
ments, greenish ; tufts of fertile filaments
rather dense, entangled, suberect. On de-
caying fungi and other bodies.

"a. alternatus, Berk. Sporidia grey- black,
. subtruucate ; fertile plants branched alter-
nately in a zigzag manner, erect or decum-
bent,"forming extremely minute orbicular
patches on damp paper. Ann. N. H. 1838,
i. p. 262, pi. 8. f. 11.

A. ditbius, Corda, would appear to differ
generically from the above. Mr. Berkeley
states that its capitular cells bear linear-
processes, each surmounted by four sterig-
mata, on which are attached the chains of
spores. On dung. Corda, Ic. ii. t. 11.
fig. 77.

BiBL. Berkeley, Hooker^ s Br. Fl. ii. part
2, p. 349 ; Ann. K. II. i. 262, vi. 436, 2nd
ser. vii. 100; Crypt. Bot. p. 298; Fries,
Syst. Mycoloy. iii. 383 ; Corda, Ic. Fimy. ;
Robin, Parasites, p. 515.

ASPEROCOC'CUS, Lamour.— A genus
of Dictyotacese (Fucoid Alga?), of which
three species are found on the British coast.
The fructification consists of groups of spo-
ranges (commonly called spores), intermixed
with paraphyses, scattered over the whole
suriiice of the frond. When mature these
sporanges discharge zoospores.

BiBL. Harvey, Mar. Alyc, 2nd ed. p. 42,
pi. 8 C. ; Phyc. Brit. t. xi., Ixxii. and cxciv.j

Thuret, Ann. Sv. Nat. 3 s.5r. xiv. p. 238 ;
Derbes and Solier, ibid. p. 208, pi. 34. fig. 11.

Fig. 44.

Fiff. 45.

Asperococcus Turneri, Dillw.
Fig. i\. Fronds, reduced to one third.
Fig. 45. Fragment of ditto, magnified 50 diameters.
Fig. 46. A section at right angles to fig. 4.i, showing the
sporanges and paraphyses, magnified 50 diameters.

ASPIDIE'.E.— A family of Polypodi-
aceous Ferns, with indusiate sori. Genera:

Didymocldcena. Sori elliptical, intramar-
ginal, terminal on a veinlet ; indusium ob-
long-elliptical, emarginate at base, attached
to the linear receptacle, free at edge.

Aspidiiim. Sori rounded, dorsal or ter-
minal ; indusium orbicular, peltate.

Nejyhrodium. Sori rounded, dorsal or ter-
minal; indusium cordato-reniform, attached
by the sinus.

Ncphrolejns. Sori round, arising from
the apex of the upper branch of a vein,
generally near the edge ; indusium roimdish
or reniform ; veins free.

Oleandra. Sori round, in a rovs^ near the
base of the compact free veinlets ; indusium
reniform.

Fadyenia. Sori oblong, biserial, termi-
nating free veinlets ; indusium large, sub-
reniform, attached by the centre, free at
margin.

BiBL. See Ferns.

ASPIDIS'CA, Ehr.— A genus of Infuso-
ria, of the family Aspidiscina.

Cliar. That of the family.

A. {Trichodn, Mull.) hjnceiis (PI. 30. fig.
15 a, under view). Carapace suborbicular,
truncated posteriorly, uncinate anteriorly;
aquatic, among Confervce, &c.; length 1-
liOO to 1-560".

A. dentindata (PI. 30. fig. 15 6, side
view). Carapace suborbicular, rounded at
the ends, truncate and denticulate on the
left side; aquatic; length 1-560". See

OxiTEICHA.

ASPIDISCINA.

[ 82 ]

ASTASIA.

BiBL. Ehrenb. Infns.; Duj. Infus.;
Steiu, hifusionsthiere &c.

ASPIDISCI'NA, Ehr.— A family of In-
fusoria.

Char. A carapace present in tlie form of
a transparent flattened shield, projecting^
beyond the mouth in front; flexible bristles
on the ventral surface of the body, with
dehcate oral cilia.

Ehrenberg describes an alimentary canal,
the inferior orifice of which alone is terminal.
Hence they coiTespond to Evjjlotes, with
the excrementitial orifice terminal.

Dujardin places them among his C'occu-

The setae, styles, or cim serve for climb-
ing, whilst by the cilia the animals are
enabled to swim.

This family should not be retained, but
the single genus of which it is constituted,
Asjndisca, referred to the Euplota.

ASPID'IUM, Schott.— A genus of Aspi-

Fig. 47.

Aspidium trifoHatiim.
An indufcium covering a soruB.

diese (Polypodiaceous Ferns), in its old
sense including many of our native species,

Fig. 48.

Aspidium trifoliatum.

Side view, cut through perpendicularly.

Magnifitd 25 diameters.

but now broken up into subdivisions, raised
to the rank of genera.

A. Lonchi/is and aci(Ieafum,mc\ud'mp loha-
tvm and anqnJare as varieties, are British.

ASPLA]NCH'NA, Gosse.— A genus of
Rotatoria, of the family Hydatinsea.

Char. Foot, intestine, and anus absent ;
eye-spots (1 to 3) and mandibles present ;
sexes separate.
A. Brightwellii{Kotommatasyrirw, Ehr. ?).

Female: jaws with a single •tooth ; eye-
spot single ; tremulous bodies attached to
an extended filament ; aquatic ; length 1-
24". Male : jaws, pharynx, and stomach
absent ; body truncate ; length 1-40".

A. priodonta (PL 4.3. fig. 7, female). 3
eye-spots ; tremulous bodies attached to a
tortuous filament; aquatic ; length — female
1-48", male 1-110" ; jaws of female serrated
(7 V).

BiBL. Brightwell, Ann. N. H. ser, 2, ii.
p. I0.3, pi. (j; Dalrvmple, Tr. Hoy. Soc.
J 849, and Ann. K. II. 1849, iii. p. 618 ;
Gosse, Ann. N. H. 1850, vi. p. 18, viii.
p. 197.

ASPLENIEVE.— A family of Polypo-
diaceous Ferns, with indusiate sori. Ge-
nera :

Asplenimn. Sori dorsal or submarginal,
linear or oblong : indusium similar in shape,
straight or curved, single or double, plane
or tumid, bursting along the outer edge.

AUantodia. Sori dorsal, linear-oblong,
attached to the primary veins ; indusium of
the same shape, and entirely enclosing them,
bursting in an irregular line down to the
centre.

Actiniopteris. Sori linear elongate, sub-
marginal ; indusium of the same shape,
folded over them, placed one on each side
of the narrow segments of the frond, and
opening towards the midrib. Frond flabel-
late.

BiBL. See Ferxs.

ASPLE'NIUil, Presl, SpIeen-wor/.—A
well-known genus of Aspleniete (Poh-podi-
aceous Ferns), containing a number of indi-
genous species.

ASSILI'NA, D'Orb.— A variety ofJVum-
midina (grouped as a subgenus), in which
the alar lobes are reduced to a minimum,
and thereby the faces of the shell are left un-
thickened, except perhaps at their centres ;
and nearly or quite all the whorls are ex-
posed. These sliells are the Xnmjnulinfe
explanatcB of D'Archiac and Haime. Assi-
lina exponens, Sow., sp., is the best type of
this subgenus of Kummulina. It abounds,
with the more perfect type, in the older
Tertiary strata of Switzerland and India.

BiBL. D'Orbigny, Ann. Sc. Kat. vii. 296
(the Modele 88 hert> referred to, however,
is an Opcrcidina); D'Archiac and .7. Haime,
Foss. Ann. de Vlnde ; Parker and Jones,
Ann. N. II. ser. 3, v. 110, and viii. 232.

ASTA'SIA, Ehr. — A genus of Infusoria
of the family Astasiaea.

Char. Unattached, no eye-spot. Flagel-

ASTASI.EA.

liform filament single, arisinp- suddenly from
the anterior part of the body, or from a
more or less deep notch in it ; oral aperture
very extensile {Kent), leading to a long
oesophagus.

Dujardin forms an unnecessary genus,
Peranema, to contain those species in
which the filament arises from tlie gradu-
ally narrowed anterior extremity of the
body.

A. hcematodes, E. (PI. 30. fig. 16). Fu-
siform, tail very short ; at fii'st green, then
red ; length 1-380".

The flagelliform filament was absent in the
specimens represented in the figure. The
substance of the body was insoluble in cau-
stic potash, even when heated to boiling,
merely becoming swollen. It exhibited nu-
merous vacuoles, which in some of the or-
ganisms were filled with green grains of
chlorophyll. The colour arose from di-
stinct granules of pigment, scattered through
the colourless substance; when treated with
solution of iodine and then sulphm'ic acid,
the AsiasicB became spherical, and were co-
loured blue, bluish green, and purplish blue,
the purple tint apparently indicating the
presence of cellulose. It was, however,
afterwards found that these colours were
produced by the acid alone.

This curious organism colours the water
of ponds &c. blood- red.

A. Ihrnnda, D. (PI. 30. fig. 17). Fusi-
form, colourless ; length 1-550".

There are other species ; but they are ill-
defined. A. 7iivalis, Shuttleworth, found in
red snow, would appear to be an active form
of Protococcits nivalis.

BiBL. See Astasi^a; also Shuttleworth,
Pibl. de Geneve, Feb. 1840; Kent, Infus.
p. 375.

ASTASI^'A, Ehr.— A family of Flagel-
late Infusoria.

Char. Body of spontaneously variable
form, mostly with one or more flagelliform
filaments. Insoluble in solution of caustic
potash.

This family corresponds nearly to the Eu-
glenia of Dujardin, who asserts the existence
of a contractile integument. Foi-m of the
body variable, sometimes becoming sphe-
rical, at others cylindrical, fusiform, &c.,
and exhibiting a head or tail-like process,
or both. The Astasipea are distinguished
from the Amcebeea by the absence of the
irregular processes sent out by the latter
from all parts of the body ; and'by the pre-
sence of a distinct moutli.

[ 83 ] ASTERIGERINA.

The forms included under the family thus
characterized are still very imperfectly un-
derstood ; and it is probable that some of
them, separated generically by Ehrenberg,
are only transitional condirions of others.
Infusoria exactly resembling Astasia hcema-
todes and Euglena viridis occur without the
flagelliform filament ; Euglena also occurs in
a resting form, surrounded by a gelatinous
envelope, like Chla})iido7Honas,iind undergoes
division into 4, 8, IG or more new indivi-
duals in this state, so as to form irregular,
floatmg Algoid patches. The gi-een bodies
make their escape from the gelatinous enve-
lopes under certain circumstances, just in
the same way as the zoospores escape from
the cells of the Confervoid Algae. This
resting form also exhibits another character,
especially in winter; the gelatinous envelope
acquires a firm, dense, membranous coat over
its periphery, like the resting spores of the
Confervoids, and in some cases this coat is
polygonal and marked with ridges &c. It
is probable that the colour of the species is
not constant, since it seems to depend upon
similar substances to that of the PalmeUacese,
which are known positively to change from
green to red, and vice versa, and even to fade
into an almost colourless state when kept in
the dark. These organisms stillrequire much
careful examination, not of isolated speci-
mens, but by watching their developmental
history constantly for extended periods and
through different seasons. More is said on
this subject under PEOTOCOCCrs.

The following Table gives the genera of
Ehrenberg and Dujardin : —

Attached CofactuTO, Ehr.

Unattached.

Two eye-spots DMigma, 'Ehr.

One flagelliform filament.
One eve-spot.

With a tail-like process Euglena, Ehr.

Without „ Amblyoyhis.'Ehi.

Ko eve-spot j ^s/a«a, Ehr. (&

IVo flagelliform filaments.
Both alike.
Animals green, with a red

eye-spot ChIoroqonimn,'E.

Colourless, no eye-spot Zygoseimis,D\x].

One anterior, the other trailing

and retractile Heteroiienxa.Jiw].

Several filaments Polyselmis, Duj.

BiBL. Ehrenberg, J??/. ; Dujardin, Infus.;
Morren, Pxibefact. d. Eaux, Brux. 1841 ;
Cohn, Protococ. plitv., Nova Acta Ac. L. C
N. C. xxii. p. 397. (Abstr. Rarj Soc, Bot.
1853, p. 352.)

ASTATIIE. See Primobdial Utricle.

ASTEPJGERI'XA, D'Orb.— A pseudo-
genus of Foraminifera, comprising species

G 2

ASTERIONELLA.

[ 84 ]

ASTEROPHORA.

of both Hotalia and Discorhina, that have
star-like patterns on one face of the shell.
In some Rotalice an astral arrangement of
subsidiary chamberlets around the umbo is
formed as in Amplmtegina ; and in several
DiscorhincB the deep radiating sulci around
the umbilicus are roofed over with distinct,
more or less perfect plates of shell.

BiBL. Carpenter, In1r. For. 204, 213.

ASTERIONELLA, Ilass.— A genus of
DiatomacefB (Cohort Fragilarise).

Distinguished by the inflation of one or
both ends of the frustules, and by the adhe-
rence of their adjacent angles into a stellate
form.

Doubtless the frustules are originally
parallel, forming a straight filament.

A.formosa (PI. 18. hg. 14). Erustules
4-8 ; in the front view somewhat more en-
larged at the attached than the free end.
Aquatic; length 1-384".

A. Ealfsii. Frustules linear ; valves at-
tenuated towards one end, constricted to-
Avards the other, which is rounded and capi-
t ite. Aquatic ; length l-fjof)".

A. Bkaheletjii. Frustides linear, enlarged
at the base. Marine ; length l-4o4".

2 other species.

BiBL. Hassall, Micr. Exam, of London
Water; Smiih, Br. iJiat. ii. 81; Greville,
Ann. K. H. I860, xvi. p. 4 ; Rabenhorst,
Flor. Alq. i. p. 141.

ASTliRODIC'TYON, Ehr. (Ber. d. Berl
Akad. 1845). See Moxactinus.

ASTERODIS'CUS, Johnson.— A genus
of fossil Diatomacefe, allied to Asterolampra
and Astcromphalox ; but distinguished by
one septum dividing halfway frcim tlie
centre, and proceeding to two of the com-
partments, the intermediate smooth ray
being smaller than the others, 3 species ;
rays from 5 to 9.

EiBL. Johnson, Stlliman's Jn. 1852, xiii.
p. 33.

ASTEROLAM'PRA, Ehr.— A genus of
fossil Diatoniaceae.

(7iar. Free ; circular ; central portion
divided by thin septa, which do not reach
the margin, but alternate with rays extend-
ing to the margin, unsupported by septa ;
fussil. Intermediate between Aclinocyclus
and Act inojity elms.

A. marylandica (PI. 25, fig. 5). Marginal
rays eight, septa eight ; interstices between
the rays exhibiting elegant curved series of
dots; diam. 1-180", Found fossil in Mary-
land.

Other species.

BiBL. Ehr. Ber. Berl. Ak. 1844, p. 73 ;
Greville {Monnqr.), Mic. Tr. 1860, p. 102,
1862, 41, 18G3, 227, 1865, 99; Kiitzing, Sp.
Alq. 129.

ASTERO'MA, D.C.— A genus of Sphte-
ronemei (Stylosporous Fungi) growing
upon leaves and stalks, forming very minute,
shghtly prominent coloured or black spots,
more or less confluent, seated on more or
less distinct radiating filaments. Fries
separates part of the species under the name
of Actinonema. Species :

A. rcticulalnm, D.C. Dothidea reticnlata,
Fr., Corda. On decaying leaves of Cnuval-
laria. Plooker, Br. Fl. ii. part 2. p. 288.

yl. f7/»/,Klotsch. On elm-leaves. Hooker,
Br. Fl. ii. part 2. p. 289.

A. PruneUce, Purt. On green leaves of
Prnnella vulgaris. Hooker, Br.Fl. ii. part 2.
p. 289.

A. Padi, Grev, On Prnnvs Padus.
Hooker, Brit. FL ii. pt. 2. p. 289 ; Berkeley,
Ann. K. II. vi. 364, pi. 11. fig. 4.

A. Bosce, Lib. On rose-leaves. Libert,
Tr. Linn. Soe. Paris, 1826; Berkeley, Ann.
iV. H. vi. p. 364, pi. 11. fig. 5.

A. labes, Berk. Ann. N. H. vi. 364. pi. 11 .
fig. 6.

A. Verontc(B, Desm. Berkeley, Mag. Zool.
Sf Bot. i. p. 511.

BiBL. Fries, Siimma Veqet. Sean. 424.

ASTEROM'PHALOS, Ehr.— A genus of
Diatomacese.

Resembles Asterolampra, except that two
of the central septa are parallel, and one of
the marginal rays absent or almost oblite-
rated.

The .species occur in the Antarctic ocean ;
the diameter of the valves lies between
1-900 and 1-47". They are distinguished
by the number and direction of the central
rays.

A. Dancinii. Central rays five, flexuous.

A. Ilookerii (PL 25. fig. 2). Central rays
six, marginal five, straight.

A. Rossii. Rays six, inflexed.

A. Buchii. Rays six, straight.

A. Bcavmnntii. Rays seven, inflexed
(PI. 18. fig. 15).

A. Iliimboldtii. Rays eight, straight.

A. Cuvierii. Rays nine, straight.

A. Brookii. Ravs ten.

BiBL. Ehr. Ber. d. Berl. Akad. 1844;
Kiitzing, Sp. Alg. 129.

ASTEROPH'ORA, Dittm.— A genus of
Sepcdoniei (Hyphomycetous Fungi), com-
posed of minute fibrous plants, growing
parasitically upon dry blackened Agarics^

ASTEROTIIRIX.

[ 80 ]

ATAX.

deriving their name from the anguLir, sonie-
-\vhat steUate spores ; now shown by Tidasne
to be the conidiiferous state of a species of
Ilifpomyces. Two British species :

A. agaricoides, Fr. Stipe solid, 1" high,
1'" or more thick, villous, bearing a head,
at first hemispherical, then plane, about 1-2"
wide, at lirst covered by a white fugacious
tonientum. with lamell;T3 uuderneatli ; spores
G-angled. On decaying Agarics {A. adustns,
pipi'ratus), in autumn, gregarious. A. li/co-
perdioidi-s, Dittm. Sturm s Deutsch. Fl.

A. hjcoperdioides, Fr. Stipe 1'' high or
obsolete; head hemispherical or globose,
witliout lamelloe beneath ; spores 5-6-angled.
In similar situations, rather more common.
Ayaricus h/coperdioides. Sow.

BiBL. Hook. Br. Ft. ii. part 2. p. 322;
Sowerby, Fungi, t. 279; Sturm, Deutsehl.
Fl. iii/t. 26; BuUiard, Herb. t. 166, 516,
fig. 1 ; Tulasne, C(irpolo(/ia, iii. p. 54.

AS'TEROTHRIX, Ktz. — An obscure
genus of Algaj.

Char. Filaments very minute, indistinctly
iointed, greenish, very rigid, stellately
branched, acutely cuspidate at each end,
floating; A. Pertyana (PL 3. fig. 5).

3 species : fresh water.

BiBL. Kiitzing, P/(yc. (?en.p.2O0; Eaben-
horst, Flor. Aly. iii. p. 391 ; Perty, Klcinst.
Lehensf. p. 216.

AStH'MATOS, Salisb.— A genus of
Cilio-flagellate Infusoria.

Char. Free, rounded, with an anterior
bundle of cilia, and a flagelliform filament.

A. ciliaris (PL 53. fig. 9). In the mucus
of the eyes, nose, and throat, in catiirrh and
hay-fever ; length 1-1200". Probably the
ciliated epithelium covering the mucous
membranes of these passages.

Kent, Inf. p. 466.

AS'TOMUM, Hampe.— A genus of Bru-
chiacese (Acrocarpous Mosses), including
some of the Phasca of Linnfeus, &c.

A. suhulatum, Hmp. = PA«sc«»i suhida-
tum, L. (fig. 49).

A. alternifoUum, Hmp. = Ph. alternifo-
lium, Dicks, Crypt, (fig. 50).

A. nitidum, \l\n.^.= Ph. axiUarCj Dicks.

BiBL. Miiller, Syn. Muscor. ; Wilson,
Bryol. Brit. p. 24.

ASTRORHI'ZA, SandahL— A relatively
large Rhizopod, related to Lituola. Vary-
ing from sphseroidal to irregularly star-
shaped, and having sometimes a disk J inch
broad, besides radii or digitated branches.
Its test is arenaceous and thick, without
any large aperture, the pseudopodia being

Fig. 49.

Fig. 50.

Astomum subulatum.
A leaf, showing the cellu-
lar structure.
Magnified -10 diameters.

Astomum alternifolium.

Section of sporange.
Magnified 40 daametera.

extruded from between its constituent sand-
grains.

BiBL. Sandahl, Of vers. Vef.-Akad. For-
handl. 1857, p. 299; Carpenter, Pr. Boy.
Soc. 1869, p. 289.

ASTROSI'GA, Kt.— A genus of Flagel-
late Infusoria. Resembling TJvdla, but
flagellum surrounded by a hyaline collar.

A. diyuncta : fresh water.

BiBL. Kent, Inf. p. 341.

ASTROTHE'LIUM, Eschw.— A genus
of Lichenaceous Lichens.

A. parmidaria. On young oaks, very
rare.

BiBL. Leighton, Lich.-Flura, p. 499.

ATAX, Duges. — A genus of Arachuida,
of the order Acariua, and family Hydrachnea.

Char. Body ovoid ; a genital fissure bor-
bered by two plates, upon each of which
are three transparent rounded tubercles ;
anterior coxae posteriorly in contact in the
median line, wedging the labium between
them anteriorly ; the two groups of posterior
coxae distant; fourth coxa very broad, in
contact with the third throughout its whole
length; palpi with the fourth joint veiy
long, attenuate-, slightly excavated towards
the end to receive the fifth joint in a state
of extreme flexion; fifth joint forming a
pointed claw ; mandibles consisting of a
thick body cut off^obliquely like the point
of a pen posteriorly, truncate anteriorly,
and terminated by a large, strong, and
slightly curved claw ; labium oval, concave
and bifid,

Several species, of various brilliant colours.

A, hidrionicus (^Hydrachna histrionica,

ATAXOPHRAGMIUM.

[ 86 ]

AULACOSIRA.

Herm.) (PI. 6. fig. 14). Body dark red, paler
in frunt of the eyes, a square black spot iu
front of them ; dorsally marked with longi-
tudinal converging striae ; five black spots
on the anterior portion of the ventral surface ;
palpi and legs blackish green.

The black spots are produced by the vis-
cera indistinctly visible through the skin.

A. Bonzi is semitransparent, yellowish,
with some brown ; parasitic iu the shell of
the freshwater mussel.

Murray states that Arrenurus viridis is
the male of Atax histrionica.

BiBL. Walckenaer, ^4y>f('/rs, iii. (Gervais) ;
Hermann, 3Iem. Aptcrol. ; Duges, Ann. d.
Sc. N. 2 ser. i. ; Koch, Deutschl.Crust., &c. ;
Claparede, Studien an Acariden {Ann. N. H.
1. 1871, 5.5); Murray, Econ. Entom. 154.

ATAXOPIIRAG'MIUM, Reuss. — The
Buliminse with arenaceous shells come un-
der this denomination.

BiBL. Reuss, Sitz. Ak. Wien. xliv. 383.
ATHERO'MA.— Atheromatous deposits
consist of globules of oil of the most varied
sizes, frequently exceedingly minute, mixed
with albuminous matter in the form of
amorphous masses or fiakes and molecules,
plates of cholesteriue and granules of carbo-
nate of lime.

ATHY'RIUM, Roth.— A subgenus of
A^pleniumCPo\y\wd.ia.CQO\xs Ferns). To this
belongs the lady-fern, A. Filix-fa'mina, for-
merly known as an Aspidium and a Ladrcea.
AT'OMA, or Astoma, Latr.= Thombi-
DIUM, pt,

ATRAC'TIUM.— A supposed genus of
Stilbacei (Hyphomycetous Fungi), charac-
terized by its fusiform elongated spores,
but now believed to be a state of some
Nectria.

BiBL. Tulasne, Carpohgla, iii. p. 104.
ATR ACTOB'OLUS, Tode. — Formerly
described as a genus of Nidulariacei (Gaste-
romycetous Fungi), is merely the egg of a
Raphiqnathns.

ATRACTOXE'MA, St. —A genus of
Flagellate Infusoria.

Char. Free, fusiform, flagellum single ;
oral aperture connected with the contractile
vesicle, nucleus central.

A. teres (PI. 53. fig. 8). Fresh water.
BiBL. Kent, Infus. p. 373.
ATRAC'TYLIS, Wright.— A genus of
marine Polypes, of the order Hydroida, and
family Atractylidie.

Char. Polypes naked, borne on a stolon,
erect, funnel-shaped, with a conical probos-

cis, suiTomided by a simple whorl of filifoi-m
tentacles.

A. arenosa. Surface sanded. On stones,
and roots of Lnminaria.

BiBL. Hincks, Hi/dr. Polypes, p. 87.

AT'RICHUM, Palis.— A genus of Moss-
es, forming a subdivision of Polytri-

CHUM.

BiBL. Wilson, Bryol. Brit. p. 202.
ATRO'PIA (Atropine). See Alkaloids.
AT'ROPOS, Leach.— A genus of Hyme-
nopterous Insects, of the family Psocidae
(Termitidse).

Characterized by the long setaceous an-
tennae, which have more than ten joints,
the absence of wings, the eyes of moderate
size, and the three-jointed tarsi.

A. pulsatorius (book-mite) is veiy com-
mon in dried collections of plants, old books,
&c., which form its food. It is about 1-20"
long, of a dirty-white or yellowish colour ;
head oblong; joints of antennae elegantly
striated transversely ; mandibles horny and
toothed ; abdomen oblong-ovate, depressed ;
posterior femora thickened.

The allied genus Psociis has the head
broad, and the posterior margin of the fore
wings with three or four cells. The species
are found upon old palings, the bark of
trees, &;c.

BiBL. Westwood, Eyitom. Text-book, 308 j
id. Introduct. 6,-c., ii. 17 & 20.

AT'THEYA, West.— A genus of Diato-
maceae.

Char. Frustules compressed, annulate ;
valves elliptic lanceolate, with a median
longitudinal line ; angles spinous.

A. decora (PI. 51. fig. 39). Druridge
Bay.

BiBL. Micr. Tr. viii. p. 152.

ATTHEY'EL'LA, Brady.— A genus of
Copepodous Entomostraca, allied to Can-
thocamptus.

2 species ; fr. water.

BiBL. Brady, Copepoda {Ray Soc.). ii. 58.

AUGITE. See Rocks.

AULACODISCUS. See Eupodlscus.

AULACOG'.RAPHA, Leighton.— A ge-
nus of GraphidetB (Lichenaceous Lichens),
fouudod on the species Atdacoyrapha {Ope-
(jrapha) elvyans, Sm., distinguished by the
peculiar furrows of. the projier mai'gins sur-
rounding the di>ks of the lirellae. Grows on
the bark of trees.

BiBL. Leitrliton, Ann. N. II. xiii. p. 389,
pi. 7, 1854; i/c/t«i-i^/. 427.

AULACOSI'RA. See Melosika.

AULISCUS.

[ 87 ]

BACILLUS.

AULIS'CUS, Ehr.— A genus of fossil
Diatomacea?.

Differs from Eupodiscus in the processes
being more solid and less fragile, and in the
markings of the valves consisting of wavy
festooned striaj, in some resolvable into
dots, in others not. But the genus seems
unnecessary.

Eupodiscus scHlptus (PI. 16. fig. 31) woidd
form a species of Auli'seus.

Auliscus pruinosus, PI. 18. fig. 60.

BiBL. Ehrenberg, Ber. d. Berl. Ak. ;
Bailev, Smit/is. Contrib. 18-54 ; Greville,
{Monogr), Micr. Tr. 1863, p. 36 ; ibid,
(neiv spec), 186.3, p. 75; 1864, pp. 82, 88 ;
186-5, p. 5 ; 1866, p. 6 ; Rabeuhorst, Flor.
Alg. p. 320.

AULOCOM'XIUM, Schwjegr.— A genus
of Mosses. See Mnium.

AVAX'TURIXE. — A mineral composed
of silex, with numerous minute scales of
mica interspersed through its substance, or
traversed in all directions by minute fissures
or cracks, giving it an elegant sparkling or
iridescent appearance.

Artificial Avanturine consists of glass
with numerous minute crystals of metallic
copper distributed through it. These crys-
tals are mostly in the form of triangular or
hexagonal plates, the angles sometimes cu-
riously prolonged or bealced.

It fonns a oeautifid microscopic object.

It was originally manufactured at Venice,
and the process kept secret. But MM.
Fremy and Clemandot have shown that it
may be prepared by heating glass with prot-
oxide of copper and iron scale (protoxide
of iron) ; the latter reduces the protoxide
of copper by combining with the oxygen so
as to form the peroxide.

BiBL. Wohler, Chem. Gaz. i. ; Fremy and
Clemandot, /. c. iv.

AVEXEL'LA, Dalyell.— A genus of In-
fundibulate Polyzoa, of the suborder Cyclo-
stomata, and family Vesicidariidfie.

Distinguished by the thread-like, nearly
simple base ; the large, scattered, solitary,
slightly contracted and curved ceUs ; and
the 20 to 24 tentacles and small gizzard.

The single species, A. Dcdyellii {fusca),
brown, occurs matted with foreign matters ;
cells about 1-16" long. On Sertuhirise, from
deepish water.

BiBL. DalyeU, Anim. of ScofJand, ii. 6-5 ;
Gosse, Mar. Zool. ii. 21 ; Hiucks, Poh/z. 526.

AVICULA'EIA. — A term applied to the
birds'-head processes of the Polyzoa. See
Polyzoa.

AZOLLA, Kaulf. — A genus of Marsile-
acese or Rhizocarpefe, consisting of a few
species of small floating plants, occurring
in Australia and throughout America. The
mode of reproduction is evidently analogous
to that of iSalrinia ; but its development has
not yet been fully examined.

BiBL. R. Brown, F/iiiders^s Voyage, ii.
App. p. 611 ; Meyen, Nova Acta, xviii.
p. 507 ; Griffith, Calcutta Ja. of N. Hist. v.
p. 227 ; Mettenius, Linncca, xx. p. 259, 1847
{Ann, des Sc. Nut. 3 ser. xi. p. 111).

B.

BACILLA'RIA, Gmeliu.— A genus of
Diatomacete.

Char. Frustules bacillif orm, at first united
transversely into a straight tabular series,
subsequently forming oblique series; valves
with a longitudinal row of puncta, and an
excentric keel ; marine.

B. paradoxa (PI. 16. fig. 14, and PI. 18.
fig. 17). Front view of frustules linear,
rectangular, valves linear-lanceolate ; length
1-220". {a, front view of oblique series of
frustules ; b, valve.)

B. socialis, Greg., and B cursoria, Donk.

BiBL. Ktitz. Sp. Alg. and Bacill. ; Smith,
Brit. Died. ii. 8 ; Rabenhorst; Fl. Alg. i.
16-5.

BACIL'LUS, Cohn.— Ageuus of Schi-
zomycetous Fungi.

Char. Filaments very minute, straight,
slender, short or of moderate length, rigid
or fiexible, moveable or not, joints indis-
tinct ; never found naturally in the Zoogloea-
form.

B. subtilis (PI. 7. fig. 18, PI. 1. fig. 19).
Filaments very slender, elongate ; joints
single or many, with a cilium at each end ;
movement flexuous, active. In stagnant
waters, kc. It forms Pasteur's butyric fer-
ment, and the hay-baciUus ; length 1-5000"
and upwards.

B. anthracis. Like the last, but general-
ly longer, motionless ; length I-6OOO" and
upwards. In the blood and tissues of cattle
and sheep, the horse, &c., producing the
disease termed Aiithrax, or splenic malig-
nant fever, the Charbon of the French, the
Milzbrand of the Germans, also the human
malignant pustule, and the wool-sorters'
disease.

B. ulna (PI. 7. fig. 20). Filaments join-
ted, thick and rigid, movement rotary and
progressive. Warming describes cilia as in

BACTEllIASTRUM.

[ 88 J

BACTPJDIUM.

Bacterium tenno. In infusions, salt and
fresh ; in stale infusions of boiled egg ; length
1-600".

B. ruher. Filaments single, or in twos
and fours, movement very active. lu a red
mucilaginous matter on rice.

Other species have been described : B.
malarice (ague-fungus), Klebs ; B. viride,
V. Ticghem ; B. leprusus, in leprosy ; and B.
iyph i ahdom iiudU.

Amylubacter is sometimes referred to
BacUlus.

Reproduction is stated to occur by fission,
and by the formation of globular or oval
spores developed within the joiuts ; some of
these form restiug-spores. In B. anthracis,
cultivated in the dog, sporanges with 3 to 6
spores are stated to be found. Cohn also
describes giobidar or elliptical strongly re-
fractive headlets, supposed to be germinated
from gonidia. See Schizomycetes.
BiBL. That of Bacterium.
BACTEEIAS 'TR UM, Shadb.— A doubt-
ful genus of marine Diatomaceae, character-
ized by the compound cylindrical frustules,
forming a filament, and the discoidal valves
with radiate marginal slender rays.

B. curvatum (I'l. 18. tig. IS). Rays en-
tire, arched ; B. furccdum, rays straight,
forked ; B. nodidosiDu, rays simple, straight,
covered with nodules ; B. WidUcJiii, rays
simple, straight.

BiBL. Shadbolt, Qu. Mic. Jn. ii. 14 ; Ra-
benhorst, Fl. Alt/, p. 322 ; Lauder, Mic. Tr.
1864, p. 7.
BAG TER ID' IUM= Bacillus.
BACTE'RIUM, Ehr.— A genus of Schi-
zomycetous Fungi.

These organisms were formerly arranged
with the Infusoria; subsequently with the
Algne, with which Davaiue, Rabenhorst,
Cohn and Cieukowski still associate them,
on account of the resemblance of form, the
grouping, the mode of multiplicatitjn, and
their affinities with the genera Beggiatoa
and Leptothrix.

Char. Cells cylindrical or elliptical, very
minute, siugle or in twos during division,
rarely four ; motion oscillatory.

Many species have been described. By
repeated subdivision Bacteria are resolved
into a Micrococcus-iovm. (CienkoMski).

B. termo (PI. 7. fig. 17r/, and Pi. 1. fig.
20). Colourless ; twice to five times as long
as broad, slightly swollen in the middle,
iointsoneor two; length 1-1000" - 1-12000";
"breadth 1-12000" - 1-50000". Occurs in
animal and vegetable infusions ; often be-

coming suiTounded with gelatinous matter
forming masses — the Zoogkea-form. Fur-
nished with a cilium at each end (DaUinger
and Brysdale, and Warming).

This is the first and true cause of ordinary
putrefaction.

B. cafemda (fig. lib). In foetid infusions,
and the excretions of typhoid fever.

B. jmnctum (fig. c). In animal infusions;
length 1-5000", breadth 1-10000".

B. triloculare (fig. lid). Oval, two to
five times as long as broad, with from 3 to
G joints ; length 1-2000" - 1-5000".

B. lineoki (fig. lie). Cells straight or
slightly cm'ved, larger than B. termo, single
or in twos ; movement active. In animal
and vegetable infusions, marine and fresh
water. Zoogloea-plasma with dark puncta.
Turns milk sour.

Some coloured species have been descri-
bed : B. xant/iiu))i, in cows' milk, colouring
it yellow ; B. si/nci/anum, in sour milk,
rendering it blue ; B. ceruginosum, in pus,
rendering it blue; B. brunneum, in brown
decomposinginfusions of maize; B. rubescens
and sulphuratum appear to be the same as
Monas vinosa.

Many of the Bacteria may be well pre-
served by simply drying them upon a
slide.

Numerous other organisms are sometimes
included under the term Bacteria, some of
them globular. The subject will be treated
generally under Schizomycetes. See also
CoccoBACTERiA'and Micrococcus.

BiBL. Ehrenb., Ivfus. ; Dujardin, Inf. ;
Sanderson, \2th and IWi Privy Council
Repts. ; Cohn, Beitraije, i. and ii. ; Pasteur,
Ann. de Chimie. 1862, 60 ; Warming, 77-
densk. Medd. Kjiibcnliavn, 1875, 322;
Lankester, Qu. Mic. Jn. 1873, 408 ; Mag-
nin, Bacteries, 1878; Koch, CoJin's Beit.
1877, ii. ; Davaine, Diet. Bncycl, Art. Bac-
terie; Archer, Qu. Mic. Jn. 1878, xviii.
455 ; Ewart (B. anthracis), Proc. Boy. Soc.
1878; DaUinger, Jn. Mic. Soc. 1878, i. 175
(figs.); Cienkowski, Mhn. Ac. Petersb.xxv.
(Qu. Mic. Jn.), IS7S, xviii. 456; Roberts,
Phil. Tr. 1874, 46G ; Waldstein, Qu. Mic.
Jn. 1880, XX. 190; Lister, Qu. Mic. Jn.
xiii. 380 ; Livon, Jn. Mic. Soc. 1879, ii. 760
(Bacteria no poison) ; Dowdeswell (Atmo-
spheric), Qu. Mic. Jn. 1878, xviii. 82 ; Klebs,
Zeitschrift, 1879; V. Tieghera, Bull. Soc.
Bot. Fr. (Jn. Mic. Soc. 1880, i. 89) ; Tyn-
dall, l^itrefaction SfC, 1881,'

BACTRIDTUM, Kunze.— A genus of
Torulacei (Coniomycetous Fungi) ; micro-

BADIiAMIA.

[ 89 ]

BANGIA.

scopic plants of tufted habit, growing upon
decaying wood, old bark, &c. ;
white at tiist, but coloured
subsequently by the condensa-
tion of the grunious contents
of the spores. Three species
are recorded as British :

£. Jlavum, Kze.
stumps.

£. Ilehellce, B.

On elm

On dead

Bactridium can-

diiium.

Magnified 200

diametera.

and Br.
On Peziza testacea.

JB. atrovirenSf B.
stumps.

BiBL. BerkeleY, Brit. Fl. ii. pt. 2. p. 350;
Cri/pt. Bot. p. 330 ; Kunze, MycoJ. lleft i.
pi. 1. iig. 2, pi. 2. figs. 20 and 21 ; Nees,
Nova Acta, ix. pi. 1. fig. 3, pi. 2. fig. 21.

BADHA'xMIA, Berk.— A genus of Myxo-
gastres (Gasteromycetous Fimgi), consisting
of little variously-coloured sacs growing in
patches on decayed oak-branches, &c. ; allied
to PItysarum, but remarkable for the spores,
at first enclosed in a common sac, adhering
in clusters. Filaments of the capilLitium
broad.

BiBL. Berk. Limi. Tr. xxi. 152, pi. 19 ;
Crypt. Bit. p. 338.

B.EOMY'CES, Pers.— A genus of Li-
chenaceous Lichens.

The fom* species are found on the earth
and stones.

BiBL. Leighton, Lich.-Fl., 50.

BAIRDIA, M'Coy. — A marine genus of
Bivahed Entomostraca, belonging to the
Ostracoda and related to the Cypridse.
First known \)j its valves alone, which are
subtriangular. Abundant, both recent and
fossil ; found also in the Palaeozoic rocks.

BiBL. M'Coy, Curb. Foss. Ireland (1844),
165 ; Jones, Money. Tert. Eniom. 51 ; G. S.
Brady, Linn. Tr. xxvi. 360 and 388 ; Jones
and Kii-kby, Q. Jn. Geol. S. xxxv. 565
(5 pis.).

BALAXI'XUS, Germ.— A genus of Co-
leoptera, of the family Curcidionidae.

B. nucum is well known as depositing its
eggs in nuts, upon which the larva lives, and
from which it escapes, leaving a hole.

The beetle is 1-3" long, with a rostrum
nearly as long as the body. Laiwa white,
with a brown head and strong jaws,

BiBL. Stephens, Brit. Col. p
val, Ent. Hortic. p. 152 ; Calwer, Kdferhuth,
548 (tig.).

BALANTID'IUM, CI. & L.— A genus
of Infusoria, fam. Bursarina.

Like Kondyhstoma, but the body dilated
behind and narrowed in front.

B. entozoon. In the human intestines,
and those of frogs.

BiBL. CI. & Lachm. Infus. p. 227.

BALSAM (Canada). The liquid resin of
the Pinus Bcdsamea. This is the ordinarily
used and best medium for the preservation
of dry transparent objects. The more co-
lourless it is, the better. It should be kept
in a wide-mouthed bottle, covered by a large
cap, fitted by grinding. A piece of iron-wire
should be kept in the bottle, so that the
desired quantity can be easily removed. It
becomes thicker by keeping, but may be
rendered thinner by mixture with oil of tur-
pentine and di<?estion at a gentle heat, or
with benzole, if too thin, it should be ex-
posed to a gentle heat in a bottle covered
with paper, to exclude dust. See Peeser-

VATION.

BALSA'MIA, Vittadini.— A genus of
Tuberacei (Ascomycetous Fungi), character-
ized by the hollows Avhich are lined by the
fructifying cells not leading to the sm'face,
and its cylindrical or oblongo-elliptic even
sporidia.

Balsamia platyspora occurs in ditferent
parts of England, and is eagerly scratched
up by squirrels attracted by its strong scent.

BiBL. Tulasne, Fvnyi Ilypoycei; Berk.
Outl. p. 378; Cooke, Handbook.

BANA'NA. See Musa.

BANGTA, Lyngb. — A genus of Porphy-
rete (Florideous Alga?), placed among the
L'lvese by most authors, but stated by M.
Thuret to be Florideous. Species marine,
forming purplish, brownish-green, or red
tufts of filaments, upon rocks and stones or
on the fronds of other Algae, from 1 to 4
inches long, or in B. eiliaris, only half a
line long. Harvey admits five, three of
them, however, as doubtful :

B. fusco-ptirpurea, Dillw. Brownish
green or purple glossy, several inches long ;
near highwater mark. Phyc. Brit. t. 96 ;
Brit. Ak/fe, t. 25 C ; Eny. Bot., t. 2055 & 2085.

B. eiliaris, Carm. Forming a minute
pink fringe on Zostera marina.

B. ? ceramicolu, Lyngbye. Purplish rose.
On small Algte ; about 1" long.

B. ? carnea, Dillw. Pale red tufts on
Confervse.

B. ? eleyans, Chauv. Minute tufts 1'" or
2'" long, rose-red, parasitic on small Algae,
rare. Harv. Phyc. Brit. t. 246.

See ScHIZOGO^'IUM.

BiBL. Harvey, Mar. Algce, 1849, 217
(figs.) ; Berthold, Jn. Mic. Soc. 1881,
i. 97.

BARBULA.

[ 90 ]

BARK.

BAR'BULA, Hedw.— A genus of Pottia-
ceous Mosses, synonymous with Tortula, and
including some of our commonest mosses,
growing on walls Szc.

BiBL. Wilson, Bryol. Brit. p. 134.

BARK. — The outer coat of the ti'imks
and branches of Dicotyledonous shrubs and
trees, succeeding to the epidermis as the
young shoots become solid and woody. Bark
is a complicated structiu'e, composed of ele-
mentary tissues of various characters ; and
the great differences of appearance which it
presents upon trees which have attained a
certain age, residt from the growth and mul-
tiplication of the elementary organs being
subject to very different laws in different
plants. Bark is the collective term applied
to the entire cortical mass outside the
cambium-region of the stem (Cambium).
It contains three distinct regions or forms
of structure ; and in young branches the
epidermis, still remaining on the outside,
constitutes a fourth.

If we examine a young shoot of the Maple
{Acer campestre) while stiU green, by making
transverse and perpendicular-radial sections,
we find the surface to be covered by an epi-
dermis composed of small cells, closely con-
joined at their sides. Under this occur six
or eight strata of thiu-waHed, colourless
cells, which stand vertically over one an-
other, and when mature are extended in
the radial direction of the branch. These
form the cork-substance, sideroiis layer, or
periderm. Beneath or within these, we find
a layer of thin-walled parenchymatous cells,
tilled with protoplasm and chlorophyll
granules, forming the cellular envelope, cork-
cambium ov jjhellogen. Interposed between
the cellular envelope and the cambium region
occur the liber-bundles (see Liber), forming
X\iQ fibrous layer of the bark. In the bark
of the ]\Iaple, the corky substance grows
very fast at first, and soon splits the epider-
mis above it, but after a certain number of
years its growth slackens, so that it seldom
acquires verj' great thickness, especially as it
is very soft and readily rubbed ofi"; the cel-
lular layer does not grow fast, merely keep-
ing pace with the enlargement of the stem
which it surrounds. The layers of liber
increase year by year so as to form a very
distinct hbrous layer.

In the Cork-Oak (Quercus Suber), the
bark of which, when young, does not differ
much from that of the Maple, the cellular
layer grows most in the earlier years, and
the epidermis is not destroyed until the third,

fourth, or fifth ; then the cork-substance
begins to increase in an important degree
by the multiplication of its cells at the inner
side, bordering on the cellular envelope. Xe w
layers of cork-cells are produced successively,
expanding much in the radial direction.
They are thin-walled and destitute of con-
tents, of squarish form (PI. 47. figs. 16 SzlT),
and soon become dry. The outer lavers
being unable to expand sufficiently to allow
the enlargement of the stem,tear irregularly,
and give the surface of the stem a rough and
cracked aspect. On old stems we observe
that the formation of these layers has not
been continuous, but in successive groups or
sets, which causes the appearance of a darker
and more solid structm-e, composed of tabu-
lar cells, at tlie points where successive sets
of layers adjoin, just as is the case at the
fines of union of the annual rings of wood in
Dicotyledonous stems. But these lines are
very irregular. The celUdar envelope takes
no shai'e in the formation of the cork of this
tree.

In the Birch (Befula olba), there is a very
decided distinction between the layers of the
cork-substance, namely between the large
thin-waUed colourless cells and the denser
tabular cells forming the dark streaks in
the cork. The epidermis is succeeded here
by a jjericlerm composed of tabular cells
with brown contents, corresponding to the
darker parts of common cork ; in stems
of 20 years' growth, the bark presents as
many as fifty lamellae of this substance,
which lamellis are separated from each other
by layers of the lax white cork-cells. The
readiness with which the latter structure
gives way causes the lamellas to peel off in
thin scales; and these bring away a portion
of the white intermediate sti*ucture on both
faces, and thus acquire their pecidiar silvery
aspect.

In the Beech (Fayics sylvatica), where the
bark is smooth, even on old trees, the growth
takes place chiefly in the liber-layers, and
the cellular envelope and cork-substance
merely expand to make room for the enlarge-
ment of the stem ; the cork-substance is
here a periderm, i. e. composed of the flat
tabular cells, not loose cork tissue. The
Holly, Ivy, and other smooth-barked trees
are analogous to tliis.

The scaling ofl"of the bark of the Plane
(Plataims occidentalis) arises from the for-
mation of layers of tabular peridermal cells
between tl)e layers of liber ; the bark out-
side the layers dries and falls away by the
\

BAKLEY.

[ 91 ]

BARTRAMIOIDEyE.

tearing of these peridernial layers. Here,
therefore, the periderm is produced from
the ceUular envelope.

In the Lime (Ti/ia), the Oak {Q.Robur),
and other trees, a similar production of
peridernial layers within the liber takes
place ; but the layers remain in situ for a
long time, and fall away ii regularly, often
persisting for a considerable number of
years as rugged, many-layered scales.

In many of the Conifers (such as the
Scotch Fir and Larch), the peridermal struc-
ture is in hke manner developed from the
cellular envelope ; here, however, the cells
are not tabular, but parenchymatous, and
multiply and enlarge so as to form a thick
layer of cork-like tissue, which loses all
relation with the medullary rays. The tur-
pentine-canals and liber-fibres, engaged in
this corky periderm, become distm-bed and
displaced' by its irregular growth.

In some plants, such as the Vine, the
Honeysuckle, &c., the bark is always stringy,
which arises from the formation of each
annual layer of liber being followed imme-
diately by the drying-up, and soon by the
destruction, of the layers of the preceding
year, so tbat no proper periderm of suberous
or cellular layers exists here after the first
year. The same takes place in the third or
fourth year in Clematis.

The scales, plates, and rings of bark
thrown off, form the rhitidome of some
authors.

The inner layers of the bark are especially
distinguished by the presence of laticiferous
canals in those plants in which that tissue
exists ; these are said by Schacht to be in
many cases a modification of the liber-tissue.
Further particulars are given on this head
under Liber, where also the intimate struc-
ture of the liber will be explained. See also
Lexticels and Cork.

BiBL. Henfrey, But. (Masters) ; Mohl,
Vei-mischt. Schrift. 1845, p. 212 ; Haustein,
Bau d. Baumrinde, Berlin, 185.3 ; Schacht,
Pflanzenzelle, p. 237 j Sanio, Pringsheirn's
Jahrb. ii. 39 ; Sachs, Bot. 107.

BARLEY. — One of the important cereal
grains,furnishedby the Hordeum sativum and
its varieties (Monocot. Plants, N. 0. Grami-
nacese). The starch of the albumen of the
seeds has a form somewhat resembling that
of wheat, but it may be distinguished un-
der the microscope (PL 46. fig. '2) ; and the
small starch-grains are more numerous and
smaller than in wheat or rye, and many of
them are in active molecular motion when

immersed in water. (See Starch.) Pearl-
barley is obtained by a peculiar mode of
grinding, by which the outer coat or shell
of the grain is removed.

BAUTRA'MIA, Hedw.— A genus of
Bartramiaceous Mosses, containing several
common species. B. poviiformis, with its
apple-like capsules, is common on dry sandy
banks.

BiBL. Wilson, Bryol Brit. p. 277.
BARTRAMIA'CE.'E.— A tribe of Bar-
tramioidese (operculate Apocarpous Mosses)
containing several genera. British genera :
Conostomum. Calyptra dimidiate. Pe-
ristome simple ; teeth sixteen, lanceolate,
equidistant ; erect lohen %oet or dry, densely
and nodosely tuberculated, with a median
line, connate in pairs at their apices, and
coherent into an oblique closed cone.

Bartramia. Cah^Jtra dimidiate. Peri-
stome either absent, simple, or double. Ex-
ternal, of sixteen lanceolate, smooth, tuber-
culate teeth, with a median line or sometimes
separating in the
middle, erect when
wetted, incurved
when dry, red. In-
ternal : a mem-
brane with sixteen
folds, produced in-
to sixteen lanceo-
late, keeled, broad
teeth, ultimately
split into two di-
vergent articu-
lated lobes, with
one to three cilia
interposed or none
(fig. 52).

Catascopinm. Calyptra hood-shaped,
smallish. Peristome simple ; teeth sixteen,
lanceolate, very short, trmicate-lanceolate,
differing in form, unequal, transversely arti-
culated, with a median line, whitish, rugu-
lose, rigid and suberect. Capsule inclined on
the collum, globose, small, discelioid, shi-
ning-brown, and ultimately gi'owing black,
thick-skimied, almost horny, without an
annulus, smooth.

BARTRA]\ni>'ULA, Br. and Sch. {Bar-
tramia, Miiller). — A genus of Mosses sepa-
rated from Bartrainia by some authors on
account of the smooth capsule and absence
of a peristome.

BiBL. Wilson, Bryol. Brit. p. 276.
BARTRAMIOI'DE^. — A family of
operculated Acrocarpous Mosses, of csespitose
habit and var^ang size. Leaves very varied

Bai'traiiiia marchica.
Magnified fragment of peri-
stome.

BARYTA.

[ 92 ]

BASIDIOSPORES.

in form, erect or reflexed, with terete nerves ;
cells parenchymatous, and, except in certain
species, furnished with solitary papillae on
the transverse walls on both faces, mostly
square or more or less hexagonal ; lax or
loosish, and densely filled with chlorophyll,
or with a persistent prinioi-dial utricle, rarely
thickened. Capsule with a long neck, funa-
rioid, pear-shaped or spherical, regular or
asymmetrical, straight or variously inchned,
smooth or grooved, with an operculum
mostly hemispherical or conical, rarely
beaked. This family is divided into two
tribes :

jMeesiace^e. Areolation of the leaf
lax, smooth, often destitute of primordial
utricle (Meesia), or lax and densely papil-
lose (Paludc'lla). Capsule erect, elongated,
with a more or less elongated neck, hence
more or less pear-shaped, smooth, the neck
bearing stomata.

Bartramiace^. Areolation either lax
and smooth, lax and papillose, dense and
smooth, or dense and papillose. Capsule
erect or inclined, horizontal or pendulous,
regular or asymmetrical, smooth or grooved,
but more or less spherical, devoid of stomata.

BARYTA.— A knowledge of the crystal-
line forms of the salts of baryta is sometimes
useful in determining the presence of this
substance.

Butxjrate of baryta (PL 10. fig. 23). When
rapidly separating from an aqueous solution,
forms a pearly film upon the surface, con-
sisting of dense aggregations of very trans-
parent crystalline laminaj, not perfectly se-
parable from each other (a). When more
slowly formed, stellate groups of crystals
are produced (6). The individual crystals
are rarely perfect ; and some are so thin and
transparent that their outlines are scarcely
distinguishable.

Hydrofluosilicate of baryta (PI. 10. fig. 24).
Its production is a test for the presence of
baryta. The crystals are scarcely aflected
by either nitric or muriatic acid.

" Svlphate of baryta (PI. 10. fig. 25). When
rapidly formed, consists of crystalline gra-
nides («). AV'hen more slowly precipitated
from dilute solutions, it consists of very
minute stellate foliaceous crystals, somewhat
resembling those of the ammonio-phosphate
of magnesia (i). See Strontia and Lime.

BASALT. See Rocks.

BASEMENT MEMBRANE, of Ani-
mals.— Is a very thin, transparent, elastic
and structureless membrane, lying between
the cutis and epidermis of the skin, and be-

tween the epithelium and submucous tissue
of the mucous membranes and their pro-
longations. It is of considerable firmness,
and serves to support the layer or layers of
epidermal or epithelial cells. It is not
always easily separable and demonstrable,
but is perhaps most readily so in the urinary
tubules of the kidneys.

In chemical composition, this membrane
mostly resembles elastic tissue.

BASIDTA. See Basidiospores.

BASIDIOMYCE'TES.— A name applied
by Sachs to those Fungi which have naked
spores situated in a distinct hymenium.
See Agaricim and Fungi.

BASIDTOSPORES.— The name applied
to the acrogenous spores produced in groups,
mostly of a definite number, more frequently
of four, on the hymenium of many Fungi,
the term basidium (sporophore, Berk.) being
applied to the four-branched cell upon which
they are attached. Basidiospores are pro-
duced both by the Hymenomycetous and
Gasteromycetous Fungi. In the former
they are found upon the external fruit-
bearins surfaces, such as the ffills or vertical
plates of Agarics, on the walls of tlie tubes
of Poly poms, &c. In the Gasteromycetes

n

v^

Development of the basidiospores of
Hymenangium gi-iseum.

they are produced upon the convoluted hy-
menium which occupies the interior of the

Fij?. 54.

Fig. 55.

Basidia and basidiospores Basidia and basidiospores
of Alelanogaster varie- of Octaviana astero-

gatug. sperma.

Magnified 400 dianieters.

Fungus in the eailier stages of growth ; and
when the spores are mature, the hymenium

BAST.

![ 93 ]

BATRACHOSPERMUM.

and tlio basidia becoming dissolved, the
spores fall loose in the cavity. The basidio-
spores sprout out gradually from the basidia,
becoming soon shut oft" by a cross septum ;
and in some rases they finally acquire a
dense and dark-coloured outer coat.

BiBL. Berkeley, Attn. K II. i. 81, pi. 4
and o, iv. 155, pi. 5; Lf^veiUe, Ann. Sc. Nat.
2 ser. viii. 391, pi. 8-11 ; Tulasne, Fiaif/i
Hi/pof/fpi, passim.

BAST or BASS. See Libeb.

BATARRE'A, Pers.— A singular genus
of Tricliogastres (Gasteromycetous Fungi),
characterized by a universal gelatinous vol va,
and a hat-shaped receptacle seated on the
top of a tall stem.

B. phalloides is occasionally found in Eng-
land, but only in a very few locaUties, either
in sand or in the du.^ty residue in the inside
of lioUow trees.

BiBL. Sow. t. 330 ; Berk. Out. p. 290.

BATHYS'IPHON, Sars. — A delicate
thread-like spicular Foraminifer.

S.JiUformis. In the Bay of Biscay and
the Norwegian fjords ; length 1" and more.

BiBL. Sars, Vidensk. Selsk. Furhandl.
1871, p. 251.

BATONE'US, Kirch.— A doubtful genus
of Phytoptidffi ; found on the roots of Popu-
lus tremula. See Phytoptid^.

BATRACHOSPER'ME.E.— Afamilyof
Confervoid (?) Algpe. Brownish-green or
purplish freshwater plants ; filamentous,
coated with gelatine. The fronds composed
of aggregated longitudinal filaments, bear-
ing at intervaii whorls of short, horizontal,
cylindrical or beaded, jointed ramidi. Dice-
cious. Fructification: ovate spores attached
to the lateral ramuli, which consist of mi-
nute dichotomous filaments. British genera :

Batrachospermum. Lateral whorled ra-
muli beaded ; spores collected in globular
knobs in the whorls.

Thorea. Stems continuous, whorled, ar-
ticulated, sometimes branched, ramuli cy-
Hndrical, the spores at their bases.

BiBL. See these genera.

BATRACHOSPERMUM, Roth .—A ge-
nus of Batrachosperme^ (Confervoid Algoe),
regarded by Thuret and A. Biaun as refer-
able to the Floridese ; consisting of delicate,
branched, filamentous plants of green, yel-
low, red, or purple colour, growing in clear
slowly rimning fresh water. The branched
axes of the plants of Batrachospenninn (fig.
56) consist of rows of large cylindrical cells
applied end to end, and increase in length
by the successive transverse ceU-division of

the terminal dome-shaped cell. While the
cells or joints of the axes are still young,
they send oft" a number of radiating pro-
cesses, which soon become cut off by septa,
so as to constitute distinct cells, and then
elongate and ramify so as to form tlie
Avliorls of articulated ramules (fig. 59),
which at length become very dense (fig.
57). From the basal cells of these branches

Fig. 56.

Fig. 57.

Fig. 59.

Fig. 58.

Fig. ofi. Batrachospermum moniliforme. Natural size.

Fig. .57. A portion of an axis with whorls of branches.
Magnified.

Fig. .58. A tuft of branches with spores in the midst.
More magnified.

Fig. .59. Highly magnified view of a few cells of an axis
with nascent radiating ramules and their descend-
ing cortical ceUs.

secondary branches gTow down perpendicu-
larly over the cell of the main axis imme-
diately below (fig. 59), forming at length a
kind of rind over it. This difters from the
analogous structure in Chara, in the fact that
there branches grow up as well as down
from each articulation of the axis, and meet
halfway. Some of the ramules which grow
out free become fertile, and produce sports
at their extremities, while others grow out
into transparent capillary points.

The spores are produced in large numbers
in each tuft, forming an agglomerated heap
(fig. 58) at each articulation. The branches
of the main axis are produced by lateral
budding of its cells, just above and as it
were in the axils of the smaller whorled

BATRACHOSPERMUM.

[ 9i ]

BEANIA.

branches. Braun has found specimens of
a. canilescens and B. Suevonim destitute of
the glomerules of spores, but with smaller
hj'aline (Antheridial) cells at the ends of
the branches, as in Nemaleon.

According to Bornet and Thuret, tricho-
gynes exist. These consist of a basal cell
(ultimately the cystocarp), communicating
by a narrow neck with the upper portion,
which is not capillary, but expands into an
oval cell, to which the antheridia adliere.
These are single, rounded cells, arising
from the summit of certain peripheral
elongated branches ; each producing a single
spermatozoid.

The specimens frequently change colour
when dried upon paper, becoming usually
much darker. Bory St. Vincent carefully
examined the distinctive characters of this
genus : and he is followed by Hassall, who,
however, erects several of his varieties into
species. The following forms are given
under Kiitzing's arrangement: —

B. momliforviB, Roth. Vaguely and
greatly branched, colour various (purple,vio-
let, green, seruginous, fuscescent, or nigres-
cent) ; whorls or nodes moniliform, distinct,
globose, those of the branches confluent.
Dillwyu, Tab. ii. ; Kiitz. Tab. Phyc. iii. pi.
22, Hassall's^jM^c/ferrantfm, stxifjiuile, and
rubmm are considered to be varieties of
this.

B. cjiganteum, Desv. Very large, purple
when dry, axes clothed with very long, bi-
furcated branches. Kiitz. Tab. Phyc. iii.
pi. 2.3. B. co7)fusum, Hass.

B.affine, Kiitz. 2\ib. Phyc. iii. pi. 24.

B. cceruhscens, Bory. ^ruginous, slen-
der, very much branched, branches tiagelli-
form, equal, slender, slightly thickened at
the tips, Avhorls of the lower and upper
branches confluent, those of the interme-
diate distinct, contiguous, depressed. Kiitz.
Tab. Phyc. iii. pi. 24.

B. vayum, Ag. ^ruginous, dichoto-
mously branched, equallj' thick throughout,
whorls all confluent. Kiitz. Tab. Phyc. iii.
pi. 25 ; var. teMuissiinum = Conf. atra, Eng.
Bot. pi. 600.

Ranenhorst admits two species, B. mori-
liforvie, with nine, and B. vagurn, with five
varieties.

BiBL. Bory St. Vincent, Ann. d. Mvscum,
xii. pi. 22, 29 ; Ilassall, Algce, p. 101 , and
pis. 13-16 and 63 ; Decaisne, Ann. d. Sc. Nat.
2 s^r. xvii. p. 340, pi. 15, i. ; Braun, Ver-
j'iingung, p. 160 (Pay Soc. 1853, p. 150) ;
Alg. Unicell. Appendix, p. 105 j Kiitzh.g,

Sp. Alg. p. 535, Tab. Phyc. iii. ; Rabenhorst,
Fl. Alg. iii. p. 404; Bornet and Thuret, Ann.
cl. Sc. N. 1867, vii. p. 144; Sachs, Bot, 1874,
293.

BDELLA, Latr. {Scims).—K genus of
Arachnida, of the order Acarina, and family
Bdellea.

Char. Those of the family (see Arach-
nida). Species numerous.

B. longicornis {vulgaris) (PL 6. fig. 31 a,
b, mandible). Scarlet; rostrum longer than
the front segment of the body ; eyes 4 ;
length 1-24".

B. cceruUpes (PI. 6. fig. 31 c, mandible).
Rostrum tolerably short and stout ; mandi-
bles thick and obtuse ; eyes 4 ; body red-
dish ; legs blue.

B. elaphus (PI. 6. fig. 44). Rostrum in-
flated at base ; carmine-red, with iridescent
shades ; eyes 2, blackish ; a long bristle on
each side.

Other species.

BiBL. Gervais, Walckenaer's Apt. p. 154 ;
Koch, Deutschl. Crust. 8)C. ; Duges, Ann. d.
Sc. Nat. i. 21 ; Murray, Peon. Entom. 144.

BDELLEA.— A family of Arachnida, of
the order Acarina.

The members are minute, more or less
soft, variously coloured, and live in damp
places beneath moss, upon the sand of caves,
&c. Palpi geniculate, attached to the sides
of the rostrum, as the antennas in the Cur-
culionidae. Movements slow. The single
genus,

BdeUa, has the characters of the family,
and includes the genera Scirus, Dug., and
Amonia, Koch.

BiBL. Gervais, Walckenaer's A2}t. p. 154;
Koch, Peidschl. Crust, ^-c.

BDELLOIDI'NA, Carter. — A sessile,
arenaceous, Lituolid Foraminifer, with nu-
merous,transverse, successive, sublabyrinthic
chambers.

BiBL. Carter, Ajin. N. II. March 1877,
p. 201.

BEAN-FLOUR.— The flour of the com-
mon bean, F(d)a vulgaris, is used to adulte-
rate wheat-flour; and that of the locust-
bean, Ceratonia siHqua, to adulterate coffee.
See Adxti-teration and Staisch.

BEAN'IA, Johnst.— A genus of Infundi-
bulate Polyzoa, of the suborder Cheilosto-
mata, and family Eucratiida;.

Distinguished by the creeping adherent
branched thread, upon which the sessile
erect scattered cells are placed, each with
two rows of spines on one side.

B. mi)-abilis. Parasitical on shells and

BEE.

[ 95 ]

BIBLARIUM.

rocks at or ^v^tlu^ low water-mark, or creep-
ing among the roots of Bai/ida {^Cellitlaria)
aviculan'a. Cells 1-24" long.

BiBL. Johnst. Br. Zooph. x. 371 ; Gosse,
Mar. Zool. ii. 15 ; Busk, Catal. (Brit. Mus.)}
Hincks, Pohjz. U5.

BEE. See Apis.

BEKR. — The fermentation by which this
liquid is produced results from the Lirowth
of the yeast-plant, a microscopic Fungus.
See Yeast and Fermentation.

\Yhen ammonia is added to beer, a preci-
pitate of the ammonio-phosphate of mag-
nesia falls, resembling that subsiding from
urine under the same circumstances (PI. 13.
fig, 3). This, in the sugar-beer as now
made, is almost absent ; and the beer is de-
prived of an important element of nutrition.

BEGGIA'TOA, Trevis.— A genus of Os-
ciJlatoriacere (or properly Schizomycetes),
distinguished by the free, rigid, sheathless
fibres, enveloped in mucus, and the w^hite
granular eudochromes. Five species : found
in warm mineral and sulphur springs.

BiBL. Rabenhorst, Fl. Ah/, ii. p. 04.

BELBA, Heyden (Dmnaus, Koch). — A
genus of Arachnida, of the order Acarina
and family Oribatea.

Char. Cephalothorax ribbed; abdomen
separated from the thorax, rounded as if
bulbous ; legs long, geniculate, with one
claw.

The species live on moss, under stones, &c.

B. (jenicuiata. Beneath the bark of the
pear-tree, &c.

BiBL. Walcken. Apttres, iii. (Gervais),
p. 256 ; Koch, Uehers. <§-c. ; Murray, Econ.
Entom. 215.

BENZOIC ACID.— This acid is well
known as occurring naturally in benzoin
and some other resins. It is found in ani-
mal secretions (urine) as a product of the
decomposition of hippuric acid. It is also
a product of the oxidation ofproteine com-
poimds. It is but slightly soluble in cold,
more readily in hot water and in alcohol,
also in ether.

Its ciystals belong to the right-rhombic
prismatic system. It is readily sublimed ;
and the crystals thus produced form shining
delicate needles. When crystallized from a
solution, it usually forms dendritically ar-
ranged superimposed plates, with angles of
90°, sometimes narrow six-sided needles or
piisms; occasionally the angles are trun-
cated, so that the inclination of the edges
amoimts to an angle of 135'^.

It is not unfrequently obtained from urine

when not fresh, in attempts to procure hip-
puric acid. It may be distinguished from
hippm-ic acid by its much greater solubility
in ether, by its crystallization in thin plates,
and their form (PI. 11. fig. 13).

BERGMEHL.— The German expression
for mountain-flour. A powdery or more or
less coherent mineral, consisting principally
of the siliceous valves of the Diatomaceae.
In some countries it is mixed with articles of
food in times of scarcity. See Diatomace^.

BERKELEY'A, Greville.— A genus of
Diatomacese (Cohort Naviculefe).

Distinguished by the navicular frustules
being immersed in the branches of the gela-
tinous frond, which is rounded at the base.

The valves are exceedingly thin, brittle
and transparent. No markings have been
detected upon them ; but there can scarcely
be a question that they exist.

B.frac)iUs(V\. 19. fig. 8). Filiform branches
mostly simple, crowded ; valves lanceolate,
obtuse ; length 1-330". British.

Branches about 1-4" in length. Found
upon marine plants and rocks.

B. adriatica. Branches lax, subdivided,
attenuate and flagelliform ; valves narrowly
lanceolate, almost linear, somewhat obtuse ;
length 1-200",

BiBL. Grev. Crj/pt. Fl. tab. 294 ; Ralfs,
Arm. N. H. 1845, xvi. p. 110; Kiitzing,
Bacill., and Sp. Ala. ; Smith, Br. Dial. ii.
67.

BET'ULA,L.— TheBirch-tree(Dicotyle-
donous Plants,N. O. Betulacese), remarkable
for its peculiar silvery peridenn. See Babe-.
The bark of B. nigra contains reservoirs filled
with an aromatic oil and also a peculiar resin,
called Birch Camphor, which is used in the
manufacture of Russia leather.

BE YRICHTA, M'Ooy.— An extinct ge-
nus, belonging probably to the Ostracoda,
very abundant throughout the palaeozoic
rocks, and presenting a great variety in their
small oblong and deeply lobed valves.
Forty-two species are recorded from the
Silurian, two from the Devonian, and seven
from the Carboniferous rocks.

BiBL. Jones, Ann. N. H. 1855, xvi. 81 &
163; 3fn. Mic. Jn. 1870, 191.

BIBLA'RIUM, Ehr.— A genus of fossil
Diatomaceae.

Distinguished from Tetracifclvs by the
frustules being single, which difi'crence pro-
bably depends upon the species only having
been found bv Ehreuberg in the fossil state.

Twelve species (Pis. 50. fig. 39; 18. figs.
38-48). Fossil in Siberia and Oregon.

BICELLARIA.

[ 96 ]

BIGENERINA.

BiBL. EhrenlDerg, Ber. d. Berl. Ak.
1844-45, and Ayin. N. II. 1848, i. 393 ; Kiit-
zing, Sp. A/ff. ; Smith, B)\ Died. ii. 37,

BICELLA'RIA, De Bl.— A genus of In-
fiindibiilate Polyzoa, of the .suborder Chei-
lostomata, and family Bicellariidfe.

B. ciliata ( CcUularia ciliata, Johnst.) (PI.
41. figs. 5 a and 5 b), is parasitical upon
Algae, Polypi, &c. within low- water mark ;
spines about eleven.

An elegant microscopic object.

B. Alcleri; spines six.

BiBL. See BrCELLAEIID^.

BICELLARIID^ (CeUuIaria, Johnst.
in part). — A family of Iiifundibulate Poly-
zoa, of the suborder Cheilostomata.

Distinguished by the erect plant-like
polypidom being dichotomously divided into
narrow hgulate branches in two or more
rows; the absence of whips (vibracula); and
the avicularia when present being stalked
and jointed. Genera (British) :

BiceUarin. Cells top-shaped, distinct,
armed with spines ; oritice looking upward.

Bugula. Cells elliptical, closely con-
tiguous ; orifice very large ; margin simple,
not thickened (avicularia frequently red or
blue).

BiBL. Johnston, Brit. Zooph. ; Busk,
Cat. (Brit. Mus.) ; Hincks, Poh/z. 67.

BICHRO'MATE OF POTASH. See
Potash.

BICOSCE'CA, Clark.— A genus of
Flagellate Infusoria.

Char, Solitary, two flagella, 1 long and
1 short; contained in a stalked horny
lorica.

B. lacustris (PI. 63. fig. 10). Pond- water,
common.

B. yracilipes. Stalk long; marine.

BiBL. Kent, Inf. p. 274.

BIDBULPH'IA, Gray.— A genus of Dia-
tomacese.

Char. Frustules compressed, quadrilateral,
connected with each other by the angles;
filaments attached by a stipes ; angles of the
frustules equal and produced ; valves covered
with depressions (visible by direct light),
giving them a cellular appearance ; centre
of valves with spines ; marine.

This genus resembles Isthmia and Amphi-
tetras in the general appearance of the frus-
tules and valves. But it difi'ers from the
former in the angles being alike, and from
the latter in the compressed side view of
the frustules. Frustules often with rounded
transverse elevations, between wliich are
costte or shallow vittse. Those in wliich

the angles are more prolonged and acute,
and the markings indistinct, are retained by
Kiitzing in the genus OdonteUa, Ag. (Den-
ticella, Elir. in part).

B. pukhella, Ehr. {B. fri-, qvinque-,
and sej)fc)iiloculuris, Kiitz.) (PI. 16. fig. 15).
Costse 3-7, central one with two or three
short spines ; produced angles rounded ;
markings coarse ; length 1-4U0 to 1-200".

B.aurita,Breh.{F\.l9.i}g.9). Markings
indistinct ; costte none ; angles horn-like ;
spines two or three, central ; length 1 -800".

B. rhombus, Smith {Zyqoceras rh.
Ehr. ?) (PI. 19. fi^. 13, Ehr.'; PI. 50. fig.
16, Smith). Markings indistinct ; costte
none ; spines near the hoop ; angles horn-
like; lejigth 1-60 to 1-260".

B. Baikyi, Sm. Markings indistinct;
costpe none; angles horn-hke; sides of frus-
tules with two slight elevations, each with
one or two long spines ; length 1-250".

B. turgida (^Cerataulus turyidus, Ehr.).
Markings faint ; costae none ; angles cylin-
drical, truncate ; frustules with a row of
short and two large submedian spines on
each side ; length 1-240".

B. Beyina. Sides of frustules each with
three rounded median elevations ; spines
none ; angles rounded, with distinct mark-
ings ; length 1-220".

Several other species, but not British.

BiBL. Kiitzing, Bacill and Sp. Alq. ;
Ehrcnb. Ber. de Berl. Ak. 1843 & 1844;
Ralfs, Ann. N. H. 1843, xii. 273 ; Smith,
Br. Diat. ii. 47 ; Greville, Mia: Tr. 1864,
pp. 9, 85 ; 1865, pp. 6, 19, 49 ; 18n6, pp. 6,
81 ; Rabenhorst, Fi Alg. i, p. 310; Pritchard,
Infus. p. 847.

BlFORrNES.— Under this name Turpin,
described certain cells occurring in the septa
of the air-chani])ers of the leaves of the Ara-
ceoe, characterized especially by the presence
of a large bundle of raphides. They contain
a thick fiuid ; and when they are placed iu
water, cndosmose causes them to biu'st and
discharge the crystals. See Raphides.

BiBL. Tm-pin, Ann. Sc. Nat. 2 &€\\ vi.
p. 5, pi. 1-5.

BIGENERl'N.N., D'Orb.— One of the
numerous modifications of the Textularian
type : instead of continuing to form bilateral
alternate (Enallostegian) chambers, it ad-
vances in growth with a straight single
(Stichostegian) series; and the aperture
becomes central, terminal, and rounded, in-
stead of being a transverse arch low down
on the septal face. If the aperture be

excentnc.

we have the Gemmulina of l)'Or-

BIGNONIACE^.

[ 07 ]

BINOCULAR.

bigny. B. agglutinans (PI. 23. fig. 50) is an
elongate and coarso-slielled variety of B.
nodosan'a. Common in many seas, and in
the fossil state.

BiiiL. D'Orbiguy, For. Foss. Vien. 237 ;
Carpenter. Litrod. For. lUl.

BIGNOXIACE.E ( Dicotyledons) .—The
wings of the seeds of this family allbrd very
beautiful objects. They are either thin
membranes composed of a layer of lignified
cells ; or, as in the Catalpas, the -sving con-
sists of a fringe of hairs.

BILE. — Three colouring - matters have
been obtained from the bile, viz. cholepyr-
rhine, biliverdine, and bilifulvine. These
Avero formerly regarded as distinct ; but
later researches have tended to show that
they are modifications of the same pigment.
Cholepi/rrhine ovhilirtihine, the colouring-
matter in its ordinary state, is characterized
by the series of tints through which it
passes when treated with nitric acid,
especially if this contain nitrous acid;
becoming first brownish, then green, bluish,
violet, red, and finally yellow. It is some-
times found in bile and the liver-cells in the
form of yellow semicrystalline gi-ains ; also
it enters into the composition of biliary
calculi.

Biliverdine is found in the bile, but not in
gall-stones; it is formed from bilu'ubine by
oxidation. It is most abundant in the bile
of the Herbivora.

Biliprasine is brown, becoming green with
acids ; it occm's in decomposing bile.

BiUfulvine is also sometimes found in bile
which has been retained in the gall-bladder.
The bile then appears thick and dark brown,
and exhibits small dark grains ; the crystals
are found in these grains. They form
longish, very fine needles, of a reddish-yel-
low colour, either single or severalcombined.
AVhen aggregated, they sometimes resemble
the crystals of lu'ate of soda, and are often
curved and twisted. Caustic potash dis-
solves them tolerably readily. Acetic acid
produces no change in them. Nitric acid
has but little efiect upon them, unless the
action is very intense, when they are decom-
posed. Yirchow notices the occurrence of
these crystals upon the walls of the cysts
of Echinococci in the liver, where we have
also found them, and in the liquid contents
of the cysts. In this instance, tAvo kinds
of crystals were met with (PL 13. fig. 15) :
some" of these were rhombs (b), others were
twsted and elegantly curved bundles of nee-
dles («)• ^Vheu first examuied, they were

yellowish-red ; but after remaining a day or
two in the liquid of the cysts, they became
almost perfectly yellow. When mounted in
balsam, the rhombs remained unaltered,
whilst the long filamentous groups of nee-
dles lost all colour, leaving a barely dis-
tinguishable transparent skeleton. Both
kinds were insoluble in acetic acid, but
soluble in potash with a yellow colour.

In morbid bile, crystals of cholesterine,
globules of fat, and small bundles of needles
of margarine are also occasionally found.
See ILematoidine.

BiBL. Gineliiis Handb. d. Chem. vii. &
viii. ; Virchow, An. d. Phartn. 1851 (Chem.
Gaz. X.); Karsten, I)e hep. et bile Crustac.
et Mollusc. ; Frey, Histol. &c. 187G, p. 551 ;
Stiideler, Fogq. Anmd. cxxxii. p. 323.
BILHARZIA. See Distoma.
BILIFULVINE. See Bile.
BILOCULI'NA, D'Orb.— One of the
Milioline Foraminifera, in which each suc-
cessive segment embraces more or less com-
pletely the preceding segments, on alter-
nate sides, so that only two chambers of
the shell are visible externally. It varies
much in form and size ; the Varieties are
very common, recent and fossil, and have
numerous names : the largest has been found
at 650 fathoms in the North Atlantic {Car-
penter). B. ringens (PI. 23. fig. 3) is taken
as the type.

BiBL. B'Orbigny, For. Foss. Vien. 261 ;
Williamson, Brit. For. 78; Carpenter,
Intr. For. 75, 78.

BIMETJA, T. S. Wright.— A genus of
Hydroid Zoophytes, family Atractylidse.

The body and lower part of the tentacles
enveloped by an opaque brown membrane.
B. vestita. Attached to zoophytes and
sea-weeds.

BiBL. Ilincks, Ili/droid Zoophutes, p. 103.
BINOCULAR MICROSCOPE.— This
has been alluded to at p. xiv of the Intro-
duction. We have no space for the figures
requisite to illustrate descriptions of the
three principal forms of binocular micro-
scope ; hence we must be satisfied with
referring to the works in which they will
be foimd. In the examination of new
structiu-es, no reliance should be placed upon
the appearances presented by objects under
binocular vision, unless controlled by the
means pointed out in the second part of the
Introduction.

The three principal forms of binocular
construction are those of Wenham, Holmes,
and Stephenson.

H

BIOMYXA.

[ 98 ]

BLATTA.

ToUes has invented a binocular eye-piece
(Beale, JIo70 c^-c, p. 15, fig.) ; and Abbe
another: Jn.Mic. Soc. 1881, i. p. 298 (fig.)-

BiBL. Wenhani, Ilicr. Tr. 1860, p. 154,
1861, p. 15, 1866, p. 103; Qu. 3Iw. Jn.
1861, p. 109 ; Holmes, M. 31. Jn. 1869, iii.
p. 274; Stephenson, 31. 31. Jn. 1870, iv,
p. 61 ; Frev, B. 3Iikr. 1881 ; Carpenter,
The 31icrosc. 1881.

BI'OLITE. See Rocks.

BIOMYXA, Leid.— A genus of Rhizo-
poda.

B. vrrf/rms. Resembles the pseudo-
podia of a Gromin, separated from the body.
Fr. Avater.

BiBL. Leidv, Proc. Phil. Acad. 1875,
{31. 31. Jn. xiV. p. 88).

BISTORA, Corda.— A genus of Fig.
Torulacei (Coniomycetous Fungi), 60.
characterized by its uniseptate
spores forming simple and solitary
bead-lilce chains at the apices of \A
short, slender, erect filaments, des- ^(
titute of septa, arising from a creep-
ing mycelium. It was separated
from torula by Corda on account
of the double character of the spores.
According to Fresenius, the chains
of spores are pedicellate as above
described, and the growth of the
chains appears to take place by
division of the terminal cell or spore.

£. mo7iilioides, Corda, of which
fig. 60 represents the chains of
spores without the pedicels, is Bri- Bispora
tish (Torj/^rt auct.). On sticks. ^ li^Xs.

BiBL. Corda, Ic Fitny. vol. i.Magmflpd
pi. 2. fig. 143 ; Fresenius, Bcitr. z. 200 diam.
3T}icolMiie, Heft 2. p. 27, pi. 6. figs. 46-54 ;
GiVville, t. 255.

BITARTRATE OF POTASH. See
Potash.

BLASIA, Micheli. — A genus of Pellieae
(Hepaticte). The British species, B. jm-
silla, L., occurs on moist heaths, not uncom-
monly in the mountainous parts of England,
Scotland, and Ireland. In addition to the
antheridia and pistillidia, and the sporanges
developed from the latter, this plant produces
i/emmce of two kinds. One kind is formed
in receptacles hollowed out of the nerve,
furnished with a long tubular beak, whence
the gemma) escape when mature. The se-
cond kind is dcscribcnl as black spherical
masses of granular or pulpy substance, and
occur within the epidermis on the under side
of the frond, often covered by the scales.

liiBL. Hooker, Brit. JunyermannicP, t.

Fig

Blastotrichum confc-rvoides.

Fragment of fertile filament.
Magnified 200 diameters.

82-84 ; Enq. Bot. t. 1328; Brit Fl. ii. part
1. 130; Sachs, i^oi-. p. 347.

BLASTOT'RICHUM, Corda.— A sup-
posed genus of Dematiei (Hj^phomycetous
Fungi), of curious habit, growing in and out
of water upon aquatic plants. B. confer-
voides, Corda (fig. 61), forms felted tufts of
an agreeable rose-
colour upon li\ing
and dead parts of
aquatic Euphor-
hicE, in autumn.
The filaments are
very much liranch-
ed, the brauchlets
dichotomous and
subulate ; the
spores rose-colour-
ed, containing a
gelatinous nucleus
within. The spores
are irregidarly di-
vided; and some
remain imperfect ;
but both these and the perfectly septate
reproduce the plant when sown. The
form occurring above the surface of the
water IS of closer habit than the submerged,
in which the filaments are longer and more
lax.

Berkeley is of opinion that this plant is
only a state of some DactyUum, perhaps
D. (Trichothecium) roseiwi.

BiBL. CoiHla, Icones Fung. ii. p, 10,
pi. 9. fig. 50 ; Berkeley, Cnjpt Bot. p. 302.

BLAT'TA. — A genus of Orthopterous
Insects, of the family Blattidte.

BJatta orienta'lis is the common house
blackbeetle or cockroach. The head and
the various organs of the mouth are figured
in PI. 33. fig. 1, the upper and front view ;
fig. 2 the under view ; fig. 22 the parts of
the mouth separate.

Head oval, and concealed beneath the
large plate of the prothorax. Antenncc
(fig. 1 a, brok-en off j very long, setaceous,
pubescent, and with very numerous joints;
they are inserted close to the inner maro-ins
of the eyes ; basal joint stout and subo\^ite,
second and third squarish, larger than any
of tlie following, which are ring-shaped
towards tlie base of the antenniB, become
square (in the side view) at the middle, and
oblong at the apex. Laljrum (fig. 1 e, fig. 22
lower part of a) exsertod, entire, roundish,
truncated at the base. Mandibles (fig. 22 b)
short, stoiit, toothed at the tip and on the
inner margin; basal portion of the inner

BLEOHNE.E.

[ 99 ]

BLIGHT.

margin membranous, forming a little lobe.
Ma.iiUce (figs. 1 & 2(j, 22 c) bilobed ; inner
lobe (laciuia, fig. 22 cf) dilated and ciliated
on the inner margin, acute, curved inwards
at the apex so as to form a tooth ; outer
lobe (galea, fig. 22 c *) longer, thick, rounded
and naked ; maxillaiy palpi (figs. 1 & 2 h)
elongated, rough with short hairs, 4-jointed,
the last joint somewhat hatchet-shaped.
Labium (fig. 2-2 e) elongated, bifid, with
two more slender inner lobes ; labial palpi
(fig. 2 k) pubescent, 3- jointed, last joint
truncated obliquely. Mentum (fig. 2 1) short,
convex at the base. Eyes (tig. 1 c) kidney-
shaped.

Thorax semicircular, the base convex;
elytra coriaceous, one overlapping the other,
and with numerous nen-es. Wings large,
folded longitudinally, withnumerousnerves.
Females apterous. Abdomen flat, oval,
and terminated by two short, conical, com-
pressed, jointed appendages in both sexes ;
besides which, in the male, there are two
slender, external, not-jointed appendages or
styles, also an elongated intermediate one.
Legs long and compressed ; coxfe elongated
and stout ; femora stout with a series of
spines beneath; tibiae clothed with very
strong movable spines ; tarsi 5-jointed,
three basal joints gradually diminishing in
length ; claws curved and acute.

An Amceba and some Bursarina are para-
sitic in the intestines of Blatta.

See Insects.

BiBL. Westwood, Introd. Sfc; Kirby,
Brit. Entom. i. 12.

_ BLECH'NE^.— A family of Polypo-
diaceous Ferns.

Char. Sori linear or oblong, dorsal, paral-
lel with the midrib and edge of the seg-
ments, not close to the latter. Involucre of
the same shape as the sonis, superior,
opening towards the midrib. Gen. :

Blechnmn. Sori linear, continuous or
nearly so, parallel with and contiguous to
the midrib.

Sadleria. Sori in a continuous line close
to the midrib on both sides, placed on an
elevated receptacle. Indusium narrow, sub-
coriaceous, at first wrapped over the sorus,
then spreading.

IVooduardia. Sori sunk in cavities in
the frond, in single rows parallel with and
contiguous to the midribs of the pinnse and
pinnules. Indusium subcoriaceous, closing
over the cavity like a lid.

Doodia. Sori oblong or slightly curved,
in one or more rows parallel with and be-

tween the midribs and the margins of tbo
pinnre. Indusium membranous.

BLECH'NUM, Linn.— A genus of Ferns.
BL Spicant, With., is the Hard Fern, also
called sometimes Bl. boreale, but properly
LoM.VRiA Spicant.

The species are tolerably numerous, closely
resembling each other, and dififused -widely
throughout Tropical and South Temperate
regions.

BiBL. Hooker & Baker, Syii. Fil. 183,

BLEPHAmS'MA, Perty, = Plagio-

TOMA, pt.

BLIGHT. — This word is used in common
language in an exceedingly loose and unde-
fined way, being applied to almost every
cause of disease in plants, as well as to the
diseases themselves, which are variously ex-
plained by agencies of meteorological con-
ditions, parasitic plants and insects, opera-
ting singly or in combination. Blight is,
indeed, * in the air ' in many cases, since a
frequent source of disease in vegetation is
sudden change of temperatiu-e or hygi-o-
scopic condition of the atmosphere, deran-
ging the processes of evaporation and respi-
ration in the tender, actively developing
portions of the foliage or inflorescence of
plants. It is also often ' in the air ' in an-
other sense, but much less specially than is
commonly supposed : the plagues of para-
sitic fungi and insects which sometimes
cause such devastation, seem undoubtedly
to arise immediately from the transport of
the microscopic reproductive bodies, spores
and the like, through the air ; but the pe-
culiar atmospheric condition often obsened
as accompanying the sudden irruption of
large masses of such * blights,' are only col-
laterally connected with the development of
these bodies ; the warm overcast weather,
almost proverbially designated as the cause
or the herald of blights, is merely an index
of a condition of the atmosphere especially
favourable to the rapid multiplication of the
Fungi and lusecta which are seen to increase
so rapidly at such times ; and the germs of
these must be abeady present, through other
causes, for the production of the phenomena
rmder such circumstances.

Only a few of the animal blights need be
referred to here, such ds the plant-Uce, the
most familiar form of ' blight ' in cultivated
plants (see Aphid^) ; the ' pepper-corn ' or
' ear-cockle ' of wheat, Atu/uUhda tritici (see
ANGtirLLiTLA) ; the wheat-midge (Ceci-
D05IYIA); the vine-pest (Phyxloxeea); the
turnip-fly (Haltica); the Phytoptid^;

h2

BLIGHT.

[ 100 ]

BLOOD.

and the species of Cj/nips and allied genera,
whicli produce galls and similar excrescences
by the irritation of the vegetable tissue, re-
sulting from their presence.

Many caterpillars of moths and butterflies
are exceedingly destructive, and form a kind
of blight ; but these scarcely come within oiu*
province.

The vegetable blights, the parasitic Fungi
growing upon living specimens of the higher
plants, and displaying themselves either as
the cause or the accompaniment of some
disease and disorganization, have of late
years become objects of most earnest atten-
tion, on account both of the enormous da-
mage ■which the diseases have caused to
crops of plants of high importance to man,
and also of the many curious facts in their
history -nhich have been brought to light.
The Potato blight and the Vine disease of
recent years have incited renewed efforts to
elucidate the liistory of these productions,
as yet, howeAer, imperfectly made out. The
okl notion, that these products were the
result of skin-diseases or exanthemata of
plants, is now discarded, especially as many
of them have been grown artificially from
their spores.

The general history of the conditions of
their occurrence, and a summary of the
investigations into their history, are given
vmder the head of Parasitic Fungi. The
particular history of the more remarkable
genera will be found under the heads in-
dicated by the capitals in the following
paragi'aphs.

Corn-bUghts consist chiefly of mildew
(Puccinia), 7-ust ovred-rohin (Uredo, Tri-
CHOBASis), simtt, hunt, or hrand (Tilletia,
UsTiLAGO, PoLYCYSTis), ergot (CORDI-
CEPs), &c. Cystopus ( C/'rcf/o) attacks Cru-
ciferous plants. 3Iildeivs of pease, peaches,
hops, and many other cultivated plants are
produced by species of Erysiphe. OiDitJM
is a common mildew, and is known in many
cases to be only an earlier condition of
Erysiphe. Botrytis is another common
iniidew. yEciDiUM forms a kind of rust,
as is the case with the allied Pcestelia,
infecting pear-trees. See also Uromyces,

PoLYCYSTIS, OOLEOSPORIU.M, PrOTOMY-

ces, Epitea, Phragjiidium, FusrspoRiuM,
ToRui>A, Peridermium, Sclerotium, Spi-
Loc^^^A, Sph^ria.

BiBL. De Bary, Brandpilze, BerHu, 1853,
chap. 3. p. 102 ; Berkeley, Tr. Hort. Soc,
Gardener s Chron., passim ; A. Braun,
Krcmhlieiten dcr rflunzen, Berlin, 1854 (Q«.

Mic. Jn., July ] 854) ; Sidney, Blights of the
Jllient, Bel." Tract Soc; art. Blight, in
Brande^s Diet., the Penny Cgelop.; Lihr. of
Entertaining Knowledge ; Boisduval, Entom.
Horticole ; Ilallier, Bhytopathologie.

BLINDIA, Br. and Sch.— A genus of Di-
cranaceous Mosses, including some Weissics
and Ggmnosioma of authors.

BiBL. Wilson, Bryol. Brit. p. 57.

BLOOD.— This animal fluid, with the
general appearance of which in the hio-her
animals every one is so familiar, is no less
difficult in its microscopic study, than it is
complex in its chemical composition. In
man and mammalia, birds, reptiles and fishes,
it is a viscid liquid of a red colour. In those
of the lower classes in w^hich it exists, it is
mostly colourless, sometimes, however, red,
bluish, purplish, greenish or milky.

When examined under the liiicroscope
the blood is found to consist of a liquid por-
tion, containing in suspension a large num-
ber of minute corpuscles, which are known
commonly as the globides or corpuscles of
the blood.

In the Mammalia, Birds, Eeptiles, Am-
phibia, and Fishes generally, the liquid por-
tion, or liquor sanguinis, is nearly colourless,
or of a pale yellow tinge ; and the corpuscles
are of two kinds, one of a red colour when
viewed in mass, butpale reddish yellow when
seen singly or separately, and to these the
red colour of the blood is owing ; the others
consist of perfectly colourless bodies.

The red corpuscles are far more numerous
than the colourless ones, about 500 to 1, and
consist of delicate membranous colourless
cells enclosing a red hquid . In the Mam-
malia they assume the form of circular flat-
tened disks or discoidal cells, the sides of
which are impressed or hollowed out, so as
to make them resemble doubly concave
lenses, with rounded margins fPl. 49. figs.
21, 22 & 23) ; m the Camel tribe, however,
they are elliptical and doublv convex. In
Birds (figs. 24 & 25), Fishes (figs. 26 & 27),
Amphibia and Reptiles (figs. 2S, 29 it 30),
they are elliptical and flattened, the form of
the sides varying : thus, in Birds and Fishes
they are convex, excepting the Cyclostomes
or lamprey Order among the latter, in which
they are circular, flattened and slightly con-
cave, oidy diiiering from those of man in
being somewhat larger; and in the Lepto-
cardea — Amphioxus lanc^olatus, tho lancelet,
there are no blood-corpuscles.

In ihe Aiuphibia and Reptiles, in which they
are elliptical; very Ip'ge, and comparatively

BLOOD.

[ 101 ]

BLOOD.

tliiu, tlie surfaces of the corpuscles arc rather
concave than convex, the nucleus pi'ojectiug
somewhat laterally.

The red corpuscles of tlie Mammalia are
not furnished with a nucleus, whilst in
Birds, Fishes, and Reptiles a distinct nu-
cleus exists ; this is usually oval, but some-
times rounded in the latter.

The ctiloKrh'gs corpuscles of the Vertebrata
(figs. 21-30 b), or the lymph-corpuscles, or
the blood-leucocytes as they are sometimes
called, are spherical, of a granular appear-
ance, highly refractive, and specifically
lighter than the coloured corpuscles. They
consist of a cell-wall containing numerous
larger or smaller granules and molecules,
with one or more nuclei. Acetic acid dis-
solves the granules, and brings the nuclei to
view. Tlie cell-wall is often undistiuguish-
able, unless water be added to the corpuscles,
which being imbibed, separates it from the
contents. When blood is kept at a mode-
rate heat, these corpuscles exhibit various
Aina-ba-like processes, crawl over the slide,
and even take up particles of foreign sub-
stances, as vermilion, carmine, &c.

The blood of the Invertebrata has not
been so thoroughly examined. In many of
them there are two circulating liquids — one
coloured, and sometimes containing heema-
tine, but no corpuscles ; the other colourless,
and containing rounded or irregular granular
colourless nucleated corpuscles (figs. 31-?>5),
much resembling the colourless corpuscles
of the Vertebrata, but remarkably prone to
shoot out processes like the Amoebse.

The sizes of the coloured corpuscles of
many vertebrate animals are given in the
subjoined list, nearly all the measurements
being those of Gulliver. It may be re-
marked that, whilst the largest coloured
corpuscles occur in the Reptiles, the small-
est are found in the Mammalia, and that
the size of the corpuscles is in general
proportional to the size of the animal, in
animals of the same order, but not in those
of different orders. Thus, in the laro^er
Kummants and Rodents the corpuscles are
larger than in the smaller ones, whilst the
smallest British mammal, the Harvest-
mouse, has corpuscles as large as those of
the Horse ; and in the common mouse they
are larger than in the Horse or Ox.

Mammalia.

Bimana. Man, 1-3200 to 1-3500".
Qufidrumana. Chimpanzee (Simia Tro-
glodytes), 1-3412; Monkey {Cercopitkecus

moiin), 1-34G8; Monkey, mean of eight
other species, 1-3450 ; Lemur, mean of four
species, 1-4077.

Cheiroptera. Bat {Vespertilio murmtcs),
1-4175 ; Bat ( Vespertilio 2nj)istrellm), 1-4324.

Insectivora. Hedgehog {Erinaceus euro-
pcevs), 1-4085; Mole ( Talpa europmt ), 1-4747.

Carnivora. Badger {Meles vidf/aris),
1-3940; Bear, mean of five species, 1-3708;
Dog {Canis familiaris), 1-3542 ; Fox {Canis
Vulpes), 1-4117; Lion (Felis Leo), 1-4322;
Seal (Phoca vituliua), 1-3281.

Cctacea. Dolphin {Delphinm Phocfpna),
1-3829; Whale {Balmia Mysticetus), 1-4000 ;
Whale {Balana Boops), 1-3099 ; Manatee
(3IanatMs), 1-2400.

Pdchydermata. Elephant {Eleplim iiidi-
cns), 1-27 'ib ; Horse {Eqinis cabedlus), 1-4706 ;
Pig {Sus Scrofa), 1-4230 ; Rhinoceros indi-
cus, 1-3705.

Buminantia. Camel ( Camclus bactriamis),
length 1-3123; breadth 1-5876; Dromedary
{Cameltts dromedarius), 1. 1-3254, b. 1-5921 ;
(yo&t {Capr a Mr cus), 1-636G; Musk {Mos-
chus javanicus), 1-12325; Stag {Cervusela-
pkus), 1-4324; Ox (Bos Taurus), 1-4267;
Sheep (Oris Aries), 1-5300.

Edentata. Armadilhj (Dasypus sex-cinc-
tus), 1-3457 ; Sloth (Unau, Bradmms didac-
tylus), 1-2865.

Rodentia. Guineapig {Cavia cohai/a),
1-3538; Mouse (Mus imisculus), 1-3814;
Rabbit (Lepus cunicidus), 1-3607 ; Rat {Mus
Rattns), 1-3754.

31arsupialia. Kangaroo (Macro2}us), mean
of three species, 1-3460.

Motwtremata. Platypus, duck-billed (Or-
nithorhynchus paradoxus), 1-3000.

Birds. Chaffinch {Fringd'a c«?fe6s), length
1-2253, breadth 1-4133 ; Cuckoo ( Cuculus
canorus),\.l-2Q)2S, b. 1-3600: ^i\^\e{Aquila),
mean of four species, 1. 1-1640, b. 1-3651 ;
Fow1(6'«//ms domesticus), 1.1-2102, b.1-3466;
Gull(Mew-,Z«;-MscanMs), 1. l-1973,b.l-3839;
Humming-bird (Trochilus), 1. 1-2666; b.
1-4000; Ostrich { Strut hio camelus), 1.
1-1649, b. 1-3000 ; Owl {Strixjlammea), 1.
1-1882, b. 1-3740 ; Parrot (Psittacus), mean
of twelve species, 1. 1-2042, b. 1-3724 ; Pi-
geon (Columba), mean of sixteen species,
1. 1-2135, b. 1-3679 ; Sparrow (Fringilla do-
mestica), 1. 1-2140, b. 1-3500.

Amphihia and Reptiles. Crocodile (Croco-
dilus acutus), 1. 1-1231, b. 1-2286; Frog
(Ba7ia temporaria), 1. 1-1108, b. 1-1821°;
Lizard {Lacerta viripara), 1. 1-1660; Siren
lacertina, 1. 1-435, b. 1-800 ; Toad (Bufo
vulgaris), 1. 1-1043, b. 1-2000; Triton {Lis^

BLOOD.

[ 102 ]

BLOOD.

sotriton punctatus) , 1. 1-830; Amphiuma,\.
1-340.

Fishes, Cai-p {Oyprinus carp{<)),\.\-2\i:2,
b. 1-3429; Eel {AnquiUa vulgaris), \. 1-1745,
b. 1-2842; Jack {Esox lucius), 1. 1-2000,
b. 1-350.5; Miller's Thumb {Cottm </ohio),
1. 1-2000, b. 1-2900; Perch {Percafliwia-
tilis), 1. 1-2099, b. 1-2824 ; Tench {Ct/prinas
Tinea), 1. 1-2286, b. 1-2722.

The colourless corpuscles do not vary so
much in size in diftereut animals as is the
case with the coloured corpuscles. Those
of the human blood are about 1-2500" in
diameter.

A third corpuscular element of the blood,
related to its formation, is described by
Norris.

The red corpuscles of blood consist che-
mically of Htemoglobiue ( Haematoglobu-
line) ; and this is composed of a colouring-
matter — hsematine, and an albuminous sub-
tance — globuline. They are readily altered
in form by most liquids; those of less spe-
cific gravity than the liquor sangmnis dis-
tend them, rendering them larger, paler, and
more transparent, and effacing the lenticu-
lar appearance and the elHptical form when
present. If a small quantity of water be
added, the corpuscles in motion are seen to
be highly elastic, becoming altered in shape
when coming into contact with each other,
but resuming their form when free. If the
liquid be added in large proportion, the en-
velope or cell -membrane becomes extremely
thin and pale, until at last it is no longer
distinguishable ; sometimes it bursts. These
phenomena are the residt of endosmosis.
The red corpuscles, however, are not all
equally acted upon : some are much more
affected than others ; some even appear
almost entirely to resist the action of en-
dosmotic agents, and are found but little
altered, even when the blood is mixed with
a large proportion of water. Although
water and other endosmotic agents distend
the coloured corpuscles, and render their
envelopes so extremely transparent that
they can no longer be recognized, yet many
of them may be restored to view by the
addition of reagents which either act cxos-
motically, colour them, or rendcjr them
opaque — as solution of iodine, of bichloride
of mercmy, and various other salts. Dilute
acids act nearly in the same manner as
water, but much moi-e rapidly. Dilute
solutions of alkalies produce the same effect,
but soon dissolve them completely. Solu-
tions of neutral salts act exosmotically,

rendering them smaller, more flattened, and
producing wrinkles, folds, or a granular ap-
pearance in the enveloping membrane. Fre-
quently also they appear covered with little
points, giving them an elegant stellate
aspect; tins stellate or crenate appearance
is not uufrequently seen immediatelv that
fresh blood is examined under the micro-
scope, especially at the margins of the drop.
Two principal conditions are especially
favourable to its production, viz. a concen-
trated state of the liqidd, and an increase
in the proportion of alkaline chlorides ; the
action of alcohol also tends to produce this
condition.

The comparative size of the corpuscles
in the races of man is treated of by Kich-
ardson (3/. M. Jn. 1877, xvii. 212).

The corpuscles of the blood of the hepatic
vein are smaller, more spherical, Avithout
the central depression, and resist the action
of water for a longer time than the ordinary
corpuscles ; similar corpuscles are also met
with in the spleen. These are by some
regarded as young newly formed corpuscles ;
while those of the portal vein possess the
ordinary characters.

Matters which coagulate the albuminous
matter of the red corpuscles, such as alcohol,
tannic acid, and creosote, also heat, alter
their form, giving rise to the production
of tail-Uke processes, with adherent minute
globides, wJiich also cover the surface of
the corpuscles.' And by pressui'e the latter
are broken up into a number of similar
globules.

It is a disputed point whether the red
corpuscles have a cell-wall or not. The
action of osmotic reagents tends to show
that they have ; and " the membrane can
be distinctly seen with 1000 diameters in
the newt's corpuscle after the addition of
magenta and tannic acid " (Rutherford).
Beale shows that they may be crushed into
fragments by pressure on the cover ; but
as the haemoglobiue surely coagulates, this
is accounted for ; and moreover, the hsemo-
globine is readily soluble in water and in
serum ; and it seems difficult to understand
how it resists the solvent action of the serum
unless defended by a cell-wall.

The red corpuscles of the blood contain
or consist of Ilajmoglobine (ILematoglo-
buline). This may be obtained in a crys-
talline state by adding 6ther by drops to
defibriuated blood, and shaking until the
bright and opaque colour of the blood is
replaced by that of ^ syrupy transparence.

BLOOD.

[ 103 ]

BLOOD.

After setting aside for some hours, it sepa-
rates in fine red crystals. Or, on a smaller
scale, place a drop of blood on a slide, and
add twice as much water, mix the two, and
set aside for evaporation. The crystals will
then form, often most distinctly at the
margins.

Under very high powers, a number of very
delicate, colourless, radiating or reticular
filaments may be seen traversing the cor-
puscles, sometimes also the nucleus ; pro-
bably arising from the coagulation of the
contents.

Carbonic acid causes a cloudiness with
enlargement in the red corpuscles, removed
by oxygen or air, which also contracts
them.

Electricity produces smaller or larger
processes, the corpuscles finally becommg
globular and colourless.

The colourless corpuscles are much less
affected by reagents. Water distends them
slightly, rendering their granidations less
distinct. Acetic acid does the same to a
gi-eater extent, bringing to light the nuclei.
Alkalies dissolve them. When blood is
mixed with a large quantity of water, the
mixture shaken and set aside, a pale bufl'
precipitate subsides ; this consists of some
of the albumen thrown down from the
serum, with shreds and walls of ruptured
coloured corpuscles, a few of the latter un-
altered, and some unaltered or but shghtly
changed colourless corpuscles.

Almost immediately after the blood of
the Vertebrata has left the blood-vessels, it
begins to coagulate. Within about three
minutes, the surface of the coagulating blood
becomes gelatinous ; in about ten minutes
it is gelatinous throughout; and after a fur-
ther lapse of time, the coagulation of the
fibrine apparently attains its maximum :
this process, however, is not really com-
pleted until from twelve to thirty-six hours.
We then find a firm red clot immersed in a
yellowish liquid. The fibrine during its
coagulation entangles a large number of
the coi-puscles, which impart to it the red
colour ; this is greatest towards the lower
part of the clot. The liquid from which
the clot has separated, the serum, also con-
tains some of the globules in suspension ;
most of those not entangled in the clot,
however, subside to the bottom of the ves-
sel. The sp. gr. of the serum is about 1030.
The appearances presented under the micro-
scope by a drop of coagulating blood are
very interesting. If examined immediately

I after removal from the body, the cor-
puscles are seen to be diffused irregularly
over the field ; but after the lapse of about
a minute, the red corpuscles unite by their
broad surfaces, gradually arranging them-
selves into rows resembling strings of figs ;
these interlace, forming an irregular red net-
work, within the meshes of which the colour-
less corpuscles are seen (PL 49. fig. 37).
The latter remain isolated, having no ten-
dency to unite with the former. To observe
these phenomena, the thin glass covering
the drop of blood must not be pressed down ;
otherwise the free motion of the corpuscles
will be impeded. After a time, the fibres
break up, and the corpuscles float separately
in the serum.

The coagulated fibrine is also seen dis-
tributed over the field, partly in a granular
form, but mostly in that of a network of
very delicate fibres. Sometimes the running
together of the red corpuscles begins to take
place immediatelj" the blood has left the
body, and the rows are seen to be formed
very much more rapidly than in the healthy
fluid ; and when this is the case, the upper
surface of the clot will be found to be
free from the red colour, and more or less
cupped or concave : this upper layer is called
the huffy coat, and is in general a sign of
inflammation. Considerable doubt still
exists in regai-d to the nature of this buffy
coat. It is also met with in blood which has
been covered with a layer of oil before co-
agulation. But in the natural state it arises
from the subsidence of the corpuscles before
the commencement of the solidification of
the fibrme, whereby the particles of the
latter are brought into closer contact, thus
allowing of its greater contraction. Certain
salts prevent the separation of the fibrine in
the form of fibres, and cause it to assume
the form of minute granules or globules.

In addition to the corpuscles above de-
scribed which are constantly found in the
blood, it sometimes contains globules of oil,
and, after meals especially, two distinct
kinds of a white, extremely fine, molecular
substance — one consisting of fat, the mole-
cular base of the chyle, the other a very finely
divided albuminous substance. They render
the blood milky in appearance. The dis-
tinction of the muscular base of the chyle
from the molecidar albuminous deposit must
be effected by ether, which dissolves the
latter but not the former ; but great care
is requisite in judging of the action of
ether.

BLOOD.

[ 104 ]

BLOOD.

Some methods hare receutly been devised
for the enumeration of the blood-corpus-
cles. Malassez uses a glass tube, having a
capillary bore "with a dilatation near the
upper end, in -which is placed a glass
globule. To this end is attached an india-
rubber tube ; the other end is pointed. The
tube is accurately graduated. An artificial
serum is made of gum acacia and water,
or a saline solution of know^n strength. The
point of the tube is then inserted in the
blood to be examined, and a certain quan-
tity is sucked up. A measure of the serum
is then drawn m, and the apparatus well
shaken. The corpuscles are thus spread
through the serum so as to be diffused and
readily counted. For this purpose the
mixture is introduced into a capillary tube
fixed to a slide, and the number of corpus-
cles read oft" by the aid of a micrometer
eye-piece. The proportions of the dilution
must necessarily be carefully taken into ac-
count. The colourless corpuscles can be
enumerated in the same manner. Further
details will be found in Robin, Mio:, 477
(tigs.) ; or Rutherford, Hist., 62 (figs.).

The colour of the blood of the Vertebrata
varies according to whether it is removed
from the arteries or the vems, in the former
case being of a much lighter and brighter
red than in the latter. It is beyond our
province to enter into the details of the
causes of their difference ; suftice it to say,
that it arises principally from an alteration
in the globules, by which they are enabled
to reflect light more copiously.

In the Invertebrata the coagulation of
the blood is imperfect, and the clot much
less firm and copious than in the Verte-
brata.

The uses of the blood scarcely require
mention. It is at the same time the nutri-
trive fluid from which all the tissues of the
body are formed and renovated, and that in
which the components of the secretions are
produced and from which they are separated.
The red particles are subservient to the pur-
poses of respiration ; they are most numerous
in those animals in which the respiratory
function is most active, and which consume
the largest proportion of oxygen, as birds
and mammalia.

Development of the Coloured Corpuficks. —
In the Vertebrata, two sets of coloured cor-
puscles are developed. The first, or embry-
onic blood-corpuscles, exist alone, until
lymph and chyle begin to be formed, wlieu
they are gradually superseded by the second.

The first blood-corpuscles are formed from
colourless nucleated cells with granular con-
tents, identical with the formative cells of
the embryo, by their losing the granules
and becoming filled with haematine. These
coloured, nucleated, primary blood-cells,
which are spherical, larger and more deeply
coloured than the coloured blood-corpuscles
of the adult, form, with the colourless for-
mative cells, the only elements of the blood.
Soon, however, many of them begin to in-
crease by division (PI. 49. fig. 3G), becoming
elliptical and flattened, and closely resem-
bling tlie coloured corpuscles of Reptiles,
producingtwo, rarely three or four roundish
nuclei, and then becoming resolved into two,
three, or four new cells by the formation of
one or more annular constrictions. These
corpuscles then gradually lose their nuclei,
become flattened and excavated laterally,
and form perfect coloured corpuscles.

The formation of the second set, or those
produced after birth and in adults, is more
obscure. The most probable view appears
to be that they are produced from the lymph
and chyle-corpuscles, or certain corpuscles
in the spleen and liver, by their losing their
nuclei, becoming flattened, and producing
hfematine. At aU events, corpuscles appa-
rently identical with the so-called proper
corpuscles of the chyle, siu'rouuded with a
membrane which is more or less distended
with a red liquid, are met with in the chyle
and lymph, and occasionally, but rarely, in
the blood itself. Physiologists are not
agreed as to the above views ; but the pre-
ponderance of evidence appears decidedly
in their favour. Recklinghausen has di-
rectly observed the conversion of the colom'-
less corpuscles of the frog into the coloured
corpuscles.

As unusual constituents of blood, may be
mentioned : —

1 . Cells or masses of protoplasm enclo-
sing coloured blood-corpuscles; found in the
blood of the spleen, liver, &;c.

2. Granule-cells, either colourless or con-
taining granules of pigment.

3. Peculiar concentric bodies, three or
four times as large as the coloured corpus-
cles of the blood, resembling those found in
the thymus gland.'

4. An vm usually large number of colour-
less corpuscles in Leucocytha^mia.

5. Pus-corpuscles.

0. Caudate cells, sometimes containing
pigment.

7. Crystals of haimatoidine, sometimes

BLOOD.

[ lor, ]

BLOOD.

witliin tlio coloured corpuscles, at others
free ; also crystals of licemoglobine (lipe-
luatoglobuliiie).

8. The two molecular substances previ-
ously mentioned.

9. Ilreniatozoa. Filaria hominis; other
species in the deer, dog, rat, &c. ; Bilharzia.

10. ITfematophyta. Bacteria, Bacilli ;
Sjnrochcrfc (relapsing fever).

1 1 . Altered colouring matter of the blood,
forming minute rounded or angular black
particles, contained in the colourless cor-
puscles ; in splenic disease, and malaria.

It sometimes becomes of importance to
be enabled to determine the presence of
blood in supposed blood-spots, &c., and to
distinguish that of man from that of ani-
mals. As regards the former point, it is a
matter of no great difficulty. When blood
has been dried at ordinary temperatures,
the dried serum and contents of the cor-
puscles redissolve on digestion with cold
water; and this is the condition under
which the blood is generally presented for
examination in such cases. We then have
the fibrine left undissolved, which may be
tested as to its chemical and microscopical
characters (Fibmne). The Uquid is de-
colorized by boiling, and the coagulum as-
siunes a brown colour (H^mati^'e). It
also contains iron, is unaltered in colour by
solution of potash, and contains a proteine
compound. In heating very minute quan-
tities upon a glass slide, the liquid must
always be covered with a slip of thin glass,
to prevent its drying. The mere presence
of blood can thus be chemically determined
without much difficulty; for these reac-
tions may be obsened under the micro-
scope in a very miniite quantity ; but the
distinction of small quantities of the blood
of man from that of animals by chemical
means, is impossible. We have therefore
only the morphology of the elements or
the spectral analysis to decide from. The
portions of blood presented for examination
will be almost invariably in a dried state ;
and the red corpuscles, when dried in a very
thin layer, retain so nearly their natui'al
size and outline, that any kinds of blood
which are distinguishal^le in the fresh state,
are certainly so when dried ; but it will
seldom happen that the blood Avill be dried
upon a transparent substance, and in thin
layers, permitting of its examination by
transmitted light. It must therefore be
separated from some fabric or structure, and
restored as nearly as possible to its original

appearance. This can be done b}^ digesting
the blood in a solution of bichloride of mer-
cury, Kobin's liquid fp. lOU), or a f-l-p. c.
salt-solution, and placing it under a bell-
glass for some hours; the red corpuscles may
then be detached with a camel's-Jiair pencil,
and examined. Of com-se, only those cor-
puscles should be measured which evidently
retain their natural form. The red corpuscles
of the mammalia are readily distinguishable
from those of the lower classes in the animal
kingdom by their circular diseoidal form and
the absence of a nucleus ; but those of indi-
vidual groups can only be recognized by a
difference in size. And great difference of
opinion exists as to whether the blood-cor-
puscles of man can be distinguished from
those of other animals. This point has been
particularly discussed by Richardson, Am,
Jn. Med. Sc. 1874, 102 (3/. M. Jn. 1874,
xii. 130) ; and Woodward, 31. M. Jn. 1875,
xiii. 65.

Virchow recommends that the blood-spots
be mixed with dried and powdered chloride
of sodium ; next, that glacial acetic acid be
added, and the mixture evaporated at 212°,
when the blood-crystals (chloride of hsema-
tine) are abundantly deposited.

We should recommend those who are
likely to undertake such investigations to
make their own table of sizes ; for it curi-
ously happens that in general the size of
the same objects given by different observers
varies considerably. This arises probably
from using too low a power, want of practice,
and the use of a false standard. And we
should not advise anj-one to attempt to form
a judgment in a judicial question of this
kind except he be thoroughly acquainted
with the use of the microscope and micro-
metric investigations and the most difficidt
spectroscope, and has made numerous ex-
periments upon this special point.

The corpuscles of the blood are best stu-
died while existing in the serum of that
liquid; butthe white of egg neutralized with
acetic acid exerts but little action upon them,
as is also the case with a solution of bichlo-
ride of mercury. The colourless corpuscles
are most easily recognized when the blood
has been mixed with water.

They are best preserved when dried in a
very thin layer upon a slide— a drop of blood
being placed upon the slide, and the latter
placed in a perpendicular position, so that a
very thin layer will remain ; in the liquid
state, a solution of 1 part of bichloride ot
mercury, and 2 of chloride of sodium, in

BLOOD OX BREAD.

[ 106 ]

BODO.

200 parts of water, will preserve them well
(Robin).

BiBL. Kolliker, Hand, d. Geicebel. ; tlie
Manuals on Physiology, by Mliller, Valen-
tine, Wagner, Carpenter, Forster, and
Kirkes; the Dictionaries of Todd and Bow-
man, and Wagner; Hassall, Micr. An. ;
Gulliver, GerhersAnat. ; Ann.N. H. xvii. ;
Pr. Zool. Soc. 1862, p. 91 ; Schmidt, Dia-
gnostik vcrdcichUger Flecke, &c. 18-48 ; Frey,
Histolof/ie, and the copious Bibl. therein ;
Browning {Spectroscope), Mn. Mic. Jn. ii.
p. 116 ; Rollett, Strieker's Ilandh. i. p. 574 ;
Cornil and Ranvier, Hist. path. ; Ruther-
ford, Hist. ; Beale, How 4't. ; Ralfs, Action
of Chloral hydrate, Chloroform, and Prussic
acid on {M. M. Jn., ] 871, y'u 75) ; Sorby,
M. M. Jn. 1871, vi. 9 {Spectroscope) ; Rich-
ardson, ibid. 1876, xv. 30 {Sp.) ; Carpenter,
Micr. 107 ; Beale, Hoiv 4'-c. 273 ; Osier,
M. M. Jn. 1874, xii. 141; E. Hart, Qii.
Mic. Jn. 1881, xxi. 132 (enu?n.) ; lilein,
Hist. ; Lewis, Qu. Mic. Jn. xix. 24o {Hce-
matozoa) ; ibid. 1879, 109 (Pats) ; ibid.
xix. 356 {Microphytes) ; Norris, Jn. Mic.
Soc. 1880, iii. 229 ; DowdesweU, Qu. Mic.
Jn. 1881, xxi. 154.

BLOOD OX BREAD.— Bread, flour,
paste, and similar substances are sometimes
attacked by a fermentation-fungus, which
produces patches of a blood-red (or some-
times of an amber) colour. Most authors
attribute the plants to Oidiian, or to forms
of Penicillium. Ehrenberg observed only
minute corpuscles, which he called Monas
2)rodiyiosa. We have found these patches
on sour paste, of red and yellow colour,
consisting of isolated oval cells not more
than 1-3000" in diameter ; and they were
associated with PenicilUiim ylaucum, of
which they are probably a conidial form.
This form is called Cryptococcus ylutinis by
Fresenius, who thinks it distinct from the
so-called Monas prodiyiosa of Ehrenborg,
which he found in the form of corpuscles
about 1-24000 to 1-48000" in diameter.
Montague regards the plant as a Pahnella
(prodiyiosa) ; and H. O. Stephens is of the
same opinion. Cohn rightly refers this or-
ganism to Micrococcus.

This substance sometimes occurs on de-
caying Fungi. The blood-rain on damji
wall-paper, calico, and old gourds and
melons, is the mycelium of a species of

Bibl. Ehrenb., Fresenius, Mycologie,
Heft ii. p. 78 ; Desnon, 3Icm. Soc. d. Sc.
Nat. de Cherboui-y, iv. p. 19 ; Montague,

Co7npt. Rend. 1852 ; Ann. N. H. 2 ser. x.
p. 309 ; Berkeley, Crypt. Pot. p. 264 ; Ste-
phens, Ann. K H. 1853, xii. p. 409, pi. 17.

BLOOD-VESSELS. See Vessels.

BLOOD- WORM .—The larva of Chiro-
nomus pluinosus.

BL0X.1MIA, Berk, and Br.— A genus of
SphEeronemei(?) (Stylosporous Fungi), con-
sisting of minute pimctiform sacs, soon
burstijag above, containing closely packed
tubes producing each a row of squarish
spores. An anomalous genus, allied to
Cystotrichia and Myxormia. P. truncuta
has been found on dead Wych elms.

Bibl. Berk. & Broome, Ann. N. H. 2 ser.
xiii. 468, pi. 16. tig. 17 ; Berk. Crypt. Pot. 329.

BL ri'TIA, Endlich.— A genus of PelHe*
(Hepaticaj) founded on the Junyermannia
Lyellii of Hooker, remarkable for the double
envelope of the fruit, the outer being
very short, dentate and laciniated, while
the inner forms a largish, somewhat plaited
cylinder. The antheridia arisino' from the
rib are covered
by incumbent
scales, which
are sometimes
much laciniated
and crowded
together, some-
times {J. hi-
bernica, Hook.
Prit.Junyerm.)
scarcely tooth-
ed, lax and iar-

BiBL. Hook-
er, Pr. Jung.

t. 77 & t. 78;
Xees, Lcber-
moose, iii. 313 ;

Blyttia Lyellii, magn. 2 diam.

Flora Danica, t. 2004.

BO'DO, Ehr. — A genus of Infusoria, be-
longing to the family Mouatlina. (Monads
with a tail.)

Char. A tail; no eye-spot present; mouth
terminal ; animals sometimes united in the
form of a mulberry or a bunch of grapes.

Ehrenberg describes eight species.

Some of them inhabit the intestinal canal
of frogs, insects, &c. One is green, the rest
are colourless.

Dujardin regards one syteeies {Podo gran-
dis) as comprising both his Heteromita
ovata and a species of Anisonema ; the
others he considers imperfectly examined
species belonging to his genera Cercomonas
aiid Amphimonas.

Podo yrandis, E. {I^eteromita ovata, D.).

BCEHMERIA.

[ 107 ]

BONE.

wat. ; leugth

1-940 to 1-720" (PI. 30.

fig.

18, h, c).

Fr

fig. 18 «),

Bodo socialis, E. (PI. 30.
Fr. wat. ; length 1-3000".

BiBL. Ehreuberg, Inf. ; Dujardin, Inf. ;
Pritcliard, I/if. ; Kent, Inf. 254.

BCEHME'KIA. Jacq.— A genus of Urti-
caceous plants closely allied to our common
Stinging Nettle, and characterized, like that
and other species of Urtica, by containing
tenacious liber-fibres. Two species are em-
ployed in the East Indies on this account.
£. nivca, Gaudichaud, yielding the fibre from
which Chinese grass-cloth (PI. 28. fig. 25) is
manufactured, is a native of China, where it
is largely cultivated, also in Sumatra, where
it is called Caboose, and at Pido Penang,
where it is called Rami. B. Puya, Wallich,
yields the Pooah or Puya fibre of Nepaul
and Sikkim (PI. 28. fig. 26), which has long
been extensively used in India, and is said to
equal the best European tiax when properly
di-essed ; being ordmarily roughly prepared,
it is dirty and bad-coloured, but makes ex-
cellent sail-cloth and cordage,

BiBL. Hooker, Jn. of Bot. i. & iii.

BOLACOT'RICHA, Berk.&Broome.— A
genus of Mucediues (Hyphomycetous Fun-
gi), containing one species, B. grisea, found
growing upon dead cabbage-stalks, old mats
made of Typha., &c., in tufts forming large,
effused, grey patches. Messrs. Berkeley and
Broome express themselves doubtfully as to
its real affinities. In habit it approaches
il'/y.ro^'nr/a/wi, but diftersinits simple threads
and large spores, while the spores are not in
chains as in Sporodum, or minute and linear
as in Trichokchunium. The threads are pale
purple under the microscope, strongly curved
at the tips like tendrils.

Blbl. IBerkeley and Broome, Ann. Nat.
Hist. ser. 2. vii. p. 97, pi. 5. fig. 4.

BOLETUS, Dill.— A genus of Polyporei
(Hymenomycetous Fungi), consisting of pi-
leate Fungi,or 'toad-stools,' often of large size,
growing in woods. See Basidiospores.

BOLiVI'XA, D'Orb.— A subdivision of
the Bulimine Foramiuifera, in which the
peculiar infolded notch-like aperture is re-
tained ; but the chambers grow bilaterally
alternate (Euallostegiau), instead of triserial
and obliquely spiral (Helicostegian), as in
Bidimina proper. The shell is delicate and
porous. B. punctata and B. costata are the two
leading forms. Varieties are common in all
seas, and date from the Cretaceous period.

BiBL. B'Orbigny, For. Foss. Vien. 239 ;
Carpenter, Intnd. For. 19G.

BOMBA'CE/E.— A subdivision of the fa-

mily of Dicotyledonous plants called Slercu-
liacese, some genera of wliicli are called Silk-
cotton trees, from the lung hairs which enve-
lope their seeds, as in the true cotton plants.
These hairs (from Chorisia spcciosa, Bomhcix,
sp. var., Friodendron, sp. var.) cannot be
spun, but are used for stufiiug cushions, &c.
The Adansonia, or Baobab-tree, produces a
pulpy fruit, which contains a considerable
proportion of starch. The wood of some
kinds, as of Bomhax pentandra and Pachyra
( Carolinea) minor, is remarkable for its light-
ness and almost corky texture, resulting from
being composed almost exclusively of paren-
chymatous cellular tissue, with scattered po-
rous ducts and true wood-cells. See Wood.
BONE. — It need scarcely be stated that

Fig. 63.

ir

c ?~

7.<

f ,'■

:^

Magnified 90 diameters.
Segment of the transverse section of a human meta-
carpal bone, a, outer surface of the bone, with the
outer laminae ; b, inner surface next the medullary ca-
nal, with the inner lamina;; c, ori flees of the divided
Haversian canals, with their laminae ; d, interstitial
laminae ; e, lacunae, with their canaliculi.

BONE.

[ 108 ]

BONE.

bone is the hard substance sen'in^ to give
firmness to the bodies of the Vertebrata, to
protect their delicate organs, and to form
points of attachment for muscles.

To the naked eye, bone appears to consist

Magnified 60 diameters.

Haversian canals from the superficial layers of a
human femur, at eighteen years of age, treated with
muriatic acid, a. Haversian canals; 6, osseous sub-
stance with lacunae.

C

Magnified 25 diameters.

Segment of a transverse section of the shaft of the human femur, at eigh-
teen years of age. a. Haversian canals; b, their internal oriUces; c, the
external orifices; d, osseous substance, wilh lacunrc. There' are no trans-
Verse sections of the Haversian canals, nor concentric lamina;.

of an apparently homogeneous basis^ sur-
rounding certain cavities, areolfe or cancelli ;
these are most numerous and larger towards
the centre,where, in the Mammaliaand Birds,
they form a larger cavity called 1 he med uUary
canal. This contains the marrow in the
former class, but air in the latter. Hence
we recognize in bone an outer compact and
an inner spongy portion.

On examininor a thin transverse .section of
bone under the microscope by transmitted
light and with a low power, it is found to
exhibit a number of round or oval apertures;
these are the orifices of the divided vascular
or Haversian canals (fig. 63 c). These canals
contain blood-vessels in the natural state.
They are cylindrical, sometimes flattened,
communicate freely with each other and the
medullary canal, and also open upon the
outer surface of the bone. They mostly run
parallel with the axis in the long bones ;
whilst in the flat bones they are parallel to
the surfaces, frequently following a radiating
course. The brandies by which they com-
mimicate with each other
are either transverse or ob-
lique, and pursue a radiating
or tangential course.

Hence in a longitudinal
or superficial section of bone,
the canals are seen running
longitudinally, here and
there connected by anasto-
mosing branches, and form-
ing elongated somewhat
rectangular meshes (fig. 64).
In transverse sections of
fo?tal and incompletely de-
veloped bones, scarcely any
of the apertures are met with,
but the canals are seen pur-
suing a tangential or radial
course (tig. 65 a) ; so that
the bones appear to consist
of short thick layers, each of
which belongs to two canals,
which separation is also in-
dicated by a faint median
line in each layer.

The Haversian canals vary
considerably in size, from
about 1-1000 to 1-200".

The osseous substance or
basis of bone possesses a la-
minated structure. The
laminoe are visible in sec-
tions of dried bone (fig. 63

h), but much more

BOXE.
FiR. 66.

[ 109 ]

BONE.
Fig. 67.

o b

I..

**

^■•'v

■it iV /f' ■•,,'."/", ^» '^?

>'

.ST i »

^f

',#.',

l«'

^vvx;.

- ■■'■ ", %

■0

*:,

4

it.

HU,

■''■J ^ ^^

¥

Magnified 250 diameters.

Portion of a transverse section of the shaft of the hu-
merus, treated with oil of turpentine, a. Haversian
canals; b, their laminae, each lamina with a lighter and
a darker portion, and radiating striae in the latter; c,
darker lines, probably indicating greater interruptions
in the deposition of the osseous substance; d, lacunae
without evident canaliculi.

distinctly in bone from Tvlaicli the inorganic
matter has been removed by digestion in
dihite muriatic acid. In this the laminae
are easily separable. They frequently ex-
hibit a fibmus appearance ; and near the
surfaces of the bones they run parallel with
these surfaces (fig. 63 a, b) ; but in the other
portions they mostly surround tlie Haver-
sian canals concentrically (fig. 6-3 d).

"When a section of bone is examined with
a somewhat high power, it exhibits nume-
rous dark spots, witli fine lines branching
from them on all sides ; the former are the
lacuna;, bone-corpuscles, or bone-cells (fig.
67 c, b) ; and the latter are the canalicnli or
calcigerous canals (fig. 68 b, c, d). They
derive their dark appearance in dried bone
from containing air : if this be displaced by
immersion in oil of turpentine, they become
so transparent as to be scarcely distinguish-
able (tig. 66) ; and when examined bj' re-

Magnified 100 diameters.

Section of the surface of the shaft of the femur, a.
Haversian canals ; b, side view of the lacui^ae in the
Haversian laminae ; c, surface view of lacunae.

fleeted light, they appear white. The la-
cunas are generally longer than broad, and
flattened. They are about 1-1100" in
length, 1-2000 to 1-2800" in width, and
1-3800 to 1-6000" in thickness; but their
dimensions are subject to great variety.
The canaliculi vary in breadth from
1-20,000 to 1-00,000" ; and at their narrow-
est part, which is furthest from tlie lacunpe,
they anastomose with those of the adjacent
lacunte.

The walls of the lacunas and canaliculi
consist of a homogeneous calcified mem-
brane.

In a transverse section of bone, the lacunae
of the laminae surrounding the Haversian
canals are seen to be placed tangentially to
the orifices of these canals, as in figs. 66
and 68 ; whilst those of the laminae near
the surfaces are parallel with these surfaces
(fig. 6.3).

In a longitudinal section made through
the Haversian canals, they appear arranged

BONE.

[ 110 ]

Fig. 68.

.**?«'

BONE.

Fig. 69.

It

-i
7A

■■;*
J

i

^''■' .1,,

r<<

.^^

J

^w. ■■■'■'■"

Magnified 300 diameters.
Part of a transverse section of the shaft of the hnmerns.
o, Haversian canals; 6, c, d, lacuna with theii' canaliculi.

■.'■i^^Ji

Magnified 350 diameters.

Portion of the outer surface of the tibia of a calf.
The dots represent the orifices of the canaliculi,
the larger dark indistinct spots are their lacuii89
Been through the osseous substance.

Fig. 70.

Magnified 350 diameters.

Cartilage of bone, after boiling in water, n, la-
cunar corj useles ; 6, nuclei.

Fig. 71.

1

Magnified ih(\ diameters.

Ijacunne (surface view) with the cannliiuli, from (he parietal hone. The dot?i seen
tipon or between the lacunrp rc]iresent divided cnnaliculi, or their orifices opening
into the lacunee; a, a, a, groups of transversely divided canaliculi.

BONE.

[ in ]

BONE,

in numerous longitudinal rows running par-
allel -with the Haversian canals (fig. 67).
The general arrangement is, that the long
axis of the lacunne is parallel with the la-
minfe in which they are contained, or be-
tween which thoy are situated.

When the section coincides with the sur-
faces of a set of the lacuna, they present a
very elegant round or oval form (fig. 71),
iiTegularly surrounded by a perfect tuft of
canaliculi, which, being turned directly to-
wards the observer, appear more or less
shortened, and a small number of others,
which are diffused through the surface of
the lameUoe. Here and there, in the thinnest
portion of the section, a group of trans-
versely divided canaliculi is seen (fig. 71
a, a), without the lacunse to which they
belong, giving the substance a sieve-like
appearance. At the outer and inner surfaces
of the bones, the canaliculi terminate by
open mouths (fig. 69) ; and those nearest
the Haversian canals open into them.

Sharpey's perforating fibres are calcified
pointed fibres, running fi-om the periosteum
towards the Haversian canals ; they are ir-
regular and variable, and are best seen in
the bones of amphibia and fishes.

If the cartilage of bone be boiled for two
or three minutes in water or a solution of
caustic soda, the bone-cells or protoplasts
and their nuclei are often rendered very dis-
tinct (fig. 70). After macerating bone in
dilute nauriatic acid also, the lacunar
corpuscles, with longer or shorter processes,
become isolated, and appear as independent
formations.

In regard to the minute structm-e of bone,
independently of the lacunse and their cana-
liculi, a dry polished section exhibits a very
delicate dotted appearance, which makes the
bone appear granular, as if composed of
closely aggi'egated pale gi-anules, about
1-50,000 to 1-60,000" in size. This is best
seen in a transverse section.

"\Mien bone is calcined and the residue is
rubbed between two pieces of glass, or when
bone is digested in a Papin's digester, minute
inorganic gi-anules are left ; these are oval
or oblong, frequently angular, and are about
1-10,000 to 1-20,000" in diameter.

Hence bone probably consists of an inti-
mate mixture of organic and inorganic
matter, in the form of minute, firmly united
gi-auules.

The above remarks apply to human bones;
and those of the other Mammalia agree
essentially in structure with the former.

In Bii'ds, the Haversian canals are more
numerous and smaller than in the Mam-
malia, and frequently run in a direction at
right angles to the sliaft ; the lacunte are
also more numerous and smaller, and the
canaliculi very tortuous.

In Reptiles and Amphibia they are few
and very large, larger than in either of the
other classes ; the lacunae and the canaliculi
are also very large, and the latter very
numerous.

In Fishes, the structure is more irregidar :
there are no concentric laminae ; the Haver-
sian canals are sometimes absent, at others
very large and numerous ; frequently the
lacimte are absent, whilst the canaliculi are
unusually long and elegantly wavy and
branched.

The structures representing the bones in
the Invertebrata are noticed under the re-
spective classes.

The marrow or medullary tissue of bones,
consists of ordinary fatty tissue, free fatty
matter, a particidar liquid, and cells, with
vessels and nerves, surrounded and traversed
by a small quantity of areolar tissue.

In the foital or red marrow, numerous
marrow-cells resembling the colourless cor-
puscles of the blood are met with ; also
some comparatively very large or giant cells,
containing numerous nuclei (fig. 72) : Kcil-
liker's osteoclasts.

Fig. 72,

Magnified 350 times.

Giant cells, or Myeloi^Iaxes, containing nnmerous
nuclei, from the veiy young marrow of the flat bones
of the human skull.

"When animals, especially young ones, are
fed with madder, the bones speedily acquire
a beautiful red colour, principally around
the Haversian canals, because it is here that

BONE.

[ 112 ]

BONE.

the process of formation of new bone
is most active ; and the earthy mat-
ter precipitated from the blood car-
ries down Avith it the colouring
matter of the madder.

The l)Iood-Yessels of bone which
are distributed to the marrow (the
nutrient vessels), enter particular ca-
nals on the external surface ; whilst
those connected with the Haversian
canals are derived from the perios-
teum and from those of the marrow,
The two sets anastomose freely.

Chemically, bone consists of gela-
tine (not choudriue, as in cartilage),
■with phosphate of lime, small quan-
tities of carbonate of lime, carbonate
of magnesia, fluoride of calcium, and
sometimes a httle oxide of iron and
magnesia.

13y digesting bone with dilate
muriatic, chromic, or picric acid, the
inorganic matter is removed, and
by treatment with solutions of alka-
lies or incineration, the inorganic
substance or so-called cartilage may
be separated.

Fig. 73.

.i|f||»illftil|i

, - r- CJ

- ^ - . . — > c

~c« *■ ^-o^^ '

r;?^ ~

- ■ "■^,3

- : ^ i^i

.J

Fig. 74.

^ t,'^ •■

't^'

f

fi-\

Magnified 20 diameters.

Perpendicular section of the margin of the shaft: of
the femur of a child, two weeks old, sliowing thp calci-
fication of cartilage, a, cartilage and its cclis ; ft, mar-
gin of calcification; the dark stripes represent the cal-
cification of the intercellular substance, which precedes
that of the cartilage-cells, indicated by the lighter por-
tions ; c, compact calcified layer near the calcifying
margin ; e, cancelli formed by the absorption of the
calcified substance.

O/^^i.,;.,//-^!! r\J A I \im

Magnified 300 diameters.

Section of the margin of calcification of the condyle of the femur
of a child two years old, afliected with rickets, a, cartilage-cells,
single and multiplying, in rows; 6, e, more or less striated inter-
cellular substance ; rf, cartilage-cells at the very commencement
of secondary deposition; e, the same in a more advanced state,
■with greatly thickened walls, indications of the canaliculi, and
commencing deposition of calcareous salts in the walls, hence
their darker colour, the nuclei still distinct; f, still more deve-
loped and calcified cells imbedded in the intercellular substance
g, which is also becoming calcified.

In the development of bone, first the cells
of the (primary) cartilage multiply by en-
dogenous cell-growth, forming longitudinal
rows or irregular heaps. These fuse and
liquefy, so as to produce canals and cancelli,
in which blood-vessels and medulla are
formed. F.arthy matter is then deposited
in the cartilage, in a fiuely granulated form
(tig. 73) ; thus we have calcified cartihige
— but not bone.

Absorption of the caloified cartilage next
takes place,, by which larger cancelli and
canals arc formed. Lastly deposition on the

BONE.

[ 113 ]

BORACIC ACID.

walls of the cancelli and canals, of genera-
tions of stellate connective tissue corpus-
cles (Osteoblasts), forming a jiseudo-carti-
lage, occurs, which becomes calcified to form
the true bone ; the absorption of IJie calci-
fied cartihige, and the deposition in its place
of the new tissue, continuing until the
structure of the bone is perfected.

But in certain bones, as the flat sknll-
bones, the jaw-bones \'c., the bone is formed
without the aid of cartihige. Here tlie in-
ner surfeces of the periosteum produce the
osteoblasts, which ultimately become the
bone-corpuscles.

In certain morbid conditions, as inricliets,
the development of the bone is arrested at
the state of ossified cartilage ; secondary
deposit occurring in the cells of the primary
cartilage as in the case of vegetable cells
(tig. 74), the spaces left having great
resemblance to the lacunae and canaliculi of
bone.

Adventitious bone agrees in general struc-
ture with the normal; and is met with iu
all stages of development.

To examine the structure of bone, thin
sections are requisite. The method of ma-
king these is described under Preparation.
By macerating bone in muriatic acid dilu-
ted with from 10 to 20 parts of water, or
nitro-chroniic acid, the inorganic matter is
removed, the cartilage being left. Thin
sections of this can then be readily made,
and stained with picro-carmine or purpu-
rine.

The canaliculi are not easily seen when
sections of bone are immersed in liquids ;
for these fill them up. But it is a dirticult
matter to measure the lacunre, unless the
section be moistened with turpentine or
other liquid.

^'ery thin sections may be preserved in
the dry state ; those which are thick may
be mounted in inspissated Canada balsam,
which does not easily enter the canaliculi,
yet greatly increases the general trans-
parency of the section.

BiBL. Kolliker, Mikr. Anat. ii. ; Tomes,
Todd's C'l/cl. Anat. and I'/ii/s., art. Osseous
Tissue; Quekett, Tr. Mic. Soc. 1846;
Quain and Sharpey, Anat. ; H. Midler,
Sieb. Si- Kiill. Zeitschr. ix. 147 ; Rutherford,
Hist. 82 ; Schonev, Sch. Arch. xii. devel.
(M. 31. Jn. xvi."l876, 67, tigs.); Frey,
Histoloqie, and the full Bibl. therein.

BONNEMAISO'NIA, Ag.— A genus of
Laurenciaceae (Florideous Algae), bearing
pear-shaped spores in stalked ceramidia.

7, pi. 12 D ; Greville, Al(jce

B. ftspai'agoides (PI. 4. fig. 15) has a frond
4 to 12 inches lonj^-, frrmving near Inw-water
mark or deeper, of ddii-ate feathery cluiracter
and deep crimson colour.

Bibl. Harvey, Flii/c. Brit. pi. 51 ; Br.
Mar. A/(/<T, p ~ - - . —
Br. p. ]()('., pi. 1^

BURACIC ACID is the acid of the
well-known salt, borax, in which it exists
combined with soda, in the pi'oportion of two
atoms of the acid to one of tlie base. Buraric
acid is prepared by mixing three parts of
borax dissolved in tw^elve parts of boiling
water with one part of sulphuric acid or
common oil of vitriol. As the mixture cools,
the boracic acid separates in the crystalline
form. It may be purified by re-solution in
hot Avater, and subsequent cooling ; finally,
the crystals are pressed betw^eeii blotting-
paper, and dried. Ijoracic acid belongs to
the doubly oblique prismatic system ; and
the crystals possess two optic axes. Those
deposited from the hot aqueous solution are
mostly six-sided plates ; they exhibit the
phenomena of analytic crystals, but at their
lateral surfaces or edges only ; and when
their entire surface appears dark or co-
loured with the polarizer alone, the crystals
are found to be laminated. But when an
alcoholic solution of boracic acid is evapo-
rated on a slide, or, still better, when some
phosphoric acid is added to a solution of
borax, and the mixture evaporated, minute
disks or spheiiiles of the acid are formed ;
these wdien carefully examined, are seen
to be composed of minute needles radiating
from a centre, exactly as iu the oxahu'ate
of ammonia. In some of them the needles
are so closely in contact that they are un-
distinguishable and the circumference ot
the disk appears entire ; in others, the free
extremities of the needles are seen projecting
beyond the circumference. They ai-e per-
fectly colourless, and almost transparent
when viewed by ordinary light, immersed in
balsam. But when examined with polarized
light, each disk exhibits the most beautiful
cross and coloured rings, just as in the case
of the oxalurate of ammonia, in which we
have described the phenomenon more fully.

In some of the specimens of boracic acid
the crystals form -elegant arborizations,
which also possess considerable analytic
power.

The proportions of phosphoric acid and
borax requisite to produce the disks cannot
be laid down : they can only be prepared by
accident in anumber of trials. Even the same

BOERERA.

[ 11^ ]

BOTRYDmA.

solution will sometimes yield tlieni, at otliers
not. Drops of the solution should be placed
upon a number of slides, and these laid
upon a warm iron plate. The disks are much
more beautiful than those ofoxalurate of
ammonia, appearing more transparent and
the colours more brilliant, probably from
their being more highly refractiye. They
are difficult also to preserve. Even when
mounted in Canada balsam, they deliquesce
after a time, and large crystals take their
place.

BiBL. Fox Talbot, Phil Tr. 1837;
Brewster, Optics, 185.3.

BORRE'RA, Ach.,=PHYSciA.

BOS'MINA, Baird.— A genus of Ento-
mostraca, of the order Oladocera, and family
Daphniadae.

Char. Head terminated in front by a
sharp beak directed forwards, and from the
end of which project the long, many-jninted,
curved and cjdindrical superior antennje ;
inferior antennoe two-branched, one branch
with three, the other with four joints ; fire •
pairs of les's.

B. longlrosiris (Bl. 20. fig. 2). Superior
antennae with twenty joints. Fr. water.

BiBL. Baird, Brit. Entom. p. 105 ; Ley-
dig, Daphnid. p. 244 ; Norman and Brady,
Br. Entom. (No/ih. and Eur ham Trans.
I p. 5).

BOSTRYCHTA, Fries. See Cytispoea.

BOSTRYOH'IA, Montague.— A genus
of Rhodomelaceae (Florideous Algae).

B. scorpioides. Frond purple, slender,
branches involute at the end. Marine.

I^IBL. Harvey, Mar. Alqcp, 79.

BO'TACHUfe, Brady.— A genus of Cope-
podous Entomostraca.

B. cylindratus.

BiBL. Brady, Copepoda, i. 140.

BOTIIREN'CHYMA.— Pitted tissue of
Plants. See Tissue, Vegetable, and refer-
ences under that head.

BOTIIRIOCEPHALUS, Rudolphi.— A
genus of Entozoa, of the order Sterelmintha,
and family Cestoidea.

Char. Body long, flat, soft and jointed,
joints short ; head slightly tumid, oval or
somewhat quadrangular, with two opposite
depressions, or with four ear-like appen-
dages, or with four depressions furnished
witli hooks ; genital pores mesial.

The species are common in fish and
birds, more rare in mammalia, and very
rare in reptiles. They usually inhabit the
alimentary canal, sometimes the abdominal
cavity.

Thirty-four species are enimierated by
Rudolphi, ten of which are doubtful. Du-
jardin enumerates twenty-three species.

Bothriocephalus Jatiis {Tcenia lata, the
broad tape -worm) is met with in the human
intestines. The head is somewhat ovoid,
with two elongated opposite depressions,
but no hooks ; the neck generally not dis-
tinct. The joints of the body are very
broad in proportion to their length. The
orifices leading to the ovaries are situated
in the centre of the flat surface of each
joint; and around them the oviducts are
seen, having a radiated or stellate appear-
ance. Sometimes a minute body can be
seen projecting from the genital pore — the
male organ. It exclusively inhabits the
small intestines. It is rare in England.
It is 20 feet or more in length. Ova
1-350" long. Embryos ciliated, with six
hooks.

B. cordatvs, with the head cordate, is
•found in dogs, and rarely in man (Leuckart,
ci: p. 438, fig.).

' B. cristatus. With two prominences
forming a papillate rostrum. Human;
rare.

See T^iEXiA and Entozoa.

BiBL. Rudolphi, Entoz. Synops. ; Breniser,
Wiirmer, &c. ; Bujardiu, Helminth. ; Esch-
richt, Die Bothr. ; Blanchard, Ann. d. Sc.
Nat. 3 ser. xi. ; Davaine, Traite 8,-c. ;
Leuckart, Farasit. i. p. 416 ; Cobbold, Pa-
rasites, p. 106. •

BOTRYCH'IUM, Swartz.— A genus of
Ophioglossaceous Ferns. Moon-wort {Bo-
trychinm Lunaria) is an indigenous repre-
sentative.

BiBL. Hooker, Si/n. Fil., p. 447.

BOTRYDl'NA, Breb.— A genus of Pal-
melleae (Confervcid Algae). B. vuk/aris,
the only species (PL 7. fig. 9), forms a
somewhat gelatinous, blackish-green stra-
tum on the ground, on trees, or on mosses,
in damp places.

The spores, about 1-10,000" in diameter,
increase b}^ cell-division till they form sphe-
rical bodies composed of many cells, the pe-
ripheral layer of which is diaphanous, the
internal green from granular contents; the
internal vesicles multiply, with constant in-
crease of size of the whole, imtil the little
fronds acquire the dimensions of a pin's
head (1-36", Kiitzing) ; the whole cellular
structure is firmly coherent.

BiBL. Brebisson, Noiiv. Gonr. cTAIg.
(18;59), p. 3, fig. 3 ; Meneghini, Monoy. Kos-
toch. p. 98, pi. 13. fi^. 2 ; Hassall, Freshu;

BOTRYDIUM.

[ 115 ]

BOTRYLLOIDES.

Fig. 75.

Al(/(e, 320, pi. 81. fig. 2 ; Kiitzing, Tab. rin/c.
pi." 10; Rabenhorst, Fl. Ah/, ii. p. 37.

BOTR YD'IUM, VVallr." (II,/drof/asfrum,
Desv.). — A genus of Sipbonere (Confervoid
Algoe), of which one species is fonnd in
this country, growing upon damp, clayey
ground, the dried-up bottoms of ponds, &c.
A single plant, as developed from a spore or
gonidium, exhibits a remarkable character,
having a lower branched filamentous por-
tion, growing in the ground, and an erect
spherical or obovate portion, or head, about
the size of a mustard-seed, of a bright green
colour, the whole structure consisting
merely of a single cell, with one continuous
cavity running through the entire plant.
The figure (lig. 75) represents such a spe-
cimen, with a second
budding from it by ve-
getative increase ; and
in this way the plants
come to form tufts or
groups, like little bun-
ches of gi-apes ; hence
the name. The cell-
membrane acquires
considerable thickness ;
and at the period when
it is softening, and
about to dissolve to
allow of the escape of
the gouidia, it is seen
clearly to be composed „
of numerous lamelte, S^a^r/oTatetr
like that of Hydrodic-
tyon. The globular head is lined, in the
full-grown specimens, with a layer of pro-
toplasm (primordial utricle), containing
abundance of chlorophyll-globules ; and at
a certain period breaks up into numerous
free globular asexual gonidia.

When the air is dry, the protoplasm de-
scends into the branches, in little masses,
each forming a subterranean sporange, pro-
ducing zoospores ; which are also some-
times formed in a vesicle springing above
ground, and capable of resisting desicca-
tion.

Under the direct rays of the sun, the
head-protoplasm breaks up into cells, at
first green, then red. These, when free,
produce biciliated zoospores, which copu-
late.

BiBL. Greville, AJqce Br. 106, pi. 19;
Hassall, Fr. Algce,^ SOo, pi. 77. fig. 5 ; Kut-
zing, I\ova Acta, xix. pt. 2, pi. 69. figs. 1-10 ;
Braun, Verj. (Ray Soc. 1853) ; Itzigsohn,
Sot. Zeit. xiii. p. 257; Sachs, Bot. 275;

Rostafinski & ^^'oronin, Bot. Zeit. 1877
{Qn. Mic. Jn. 1878, xviii. 446).

BOTRYL'LIILE.— A family of Tunicate
Mollusca. Distinguished by the individual
bodies being united into a common mass,
which is attached ; and by the mantle being
united to the test at the orifices only.

These animals form translucent gelatinous
or cartilaginous masses, of various hues of
orange, purple, yellow, blue, grey, and green ;
and are found under stones, or rocks, or in-
crusting sea-weeds, near low-water mark.
The bodies are often arranged in elegant
star-like clusters or systems ; the anal ori-
fices usually terminating in a common cen-
tral cavity or vent. Genera :

Aplidium. Form variable; systems nu-
merous ; central cavity none ; bodies with
thorax, fore and hind abdomen ; branchial
orifice six-rayed; anal simple and indis-
tinct.

Sidymim. Incrusting ; systems conical,
truncate and starred at the summit, centre
depressed ; thorax and abdomen present ;
branchial orifice eight-rayed.

Polyclinum. Form variable ; systems nu-
merous, convex and radiating, with cen-
tral cavity ; bodies with thorax, fare ab-
domen, and long-stalked hind abdomen ;
branchial orifice six-raj^ed; anal projecting
horizontally.

Amaroucium. Lobed or incrusting, ses-
sile or stalked ; systems numerous, with a
central cavit}^ ; bodies as in Aplidium.

Zq}tocli7mm. Thin, incrusting; systems
numerous; bodies with thorax and ab-
domen ; branchial orifice six-rayed ; anal
opening into a common vent, more or less
branched.

Distoma. Sessile; cartilaginous; form va-
riable ; systems numerous, circular ; bodies
in one or two rows at unequal distances
from a common centre, with thorax and
stalked abdomen; branchial and anal ori-
fices six-rayed.

Botryllus. Incrusting, gelatinous; sys-
tems numerous ; • bodies horizontal, in stars
round a common vent ; bodies undivided ;
branchial orifice simple, remote from the
vent.

Botrylloides. As the last, but stars ir-
regular and ramifj'lng; bodies vertical;
orifices approximated.

Syntethys. Mass sessile, gelatinous, fomi-
iu"- a single system ; bodies sessile ; ori-
fices simple, without rays.

BiBL. See the Genera.

BOTRYLLOIDES, M.-Edw.— A genus

i2

BOTPtYLLUS.

[ 116 ]

BOTRYTIS.

of Tunicate Mollusca, of the family Bo-
trvUidse.

Cliar. See Botryllid^.

Four species : B. Leacliii, hyaline, pur-
plish, stars mottled white and yellow ; B.
albicans, tran -parent, stars white; B. 7-oti-
feru, yellowish, systems speckled with red ;
B. rubrum, intense orpiment-red.

BiBL. Gosse, Mar. ZooJ. ii. 34; Forbes
and Hanlev, Brit. Moll. i. 23.

BOTRYL'LUS, Gaertu. — A genus of
Tunicate MoUusca, of the family Butryl-
lidfe.

Char. See BoTRTLLiDiE,

Six species : B. Scklosseri (PI. 18. fig. 20),
stars numerous, individuals ten to twenty
or more, yellowish and reddish, common ;
B. poli/ci/clus, stars numerous, individuals
eight to twenty or more, bluish, general ;
B. riolacens, B. smaragdus, B. bivittatus,
and B. gemmeus.

BuBL. Gosse, Mar. Zool. ii. 34; Forbes
and Ilanlev, Brit. Mollusc, i. 19.

BOTRYOCOC'OUS, Kiitzing.— A genus
of floating Palmelleas (Confervoid Alga3),
forming lobed and irregular bodies enclosed
in a common, large, hyaline, membranous
sac, about 1-24" in diameter, and contain-

cells
a s'r(

1-

"000 to
or red

Fitr. 76.

ing a number of ovoid
1-5000" in diameter, of
colour.

B. Braunii. In lakes.

BiBL. Kiitzing, Sp. Alg. p. S92 ; Eaben-
horst, Fl. Ah/, iii. p. 42.

BOTRYOCYS'TIS,Kiitzing.— Described
as a genus of Palmellese
(Confervoid Alg*) found
in stagnant fre.'^^h water,
but apparently forms re-
lated to Volvox. See Vol-

YOClNEiE.

BiBL. Kiitzing, Sp. Ah/.
p. 208; Tab. Phjc. pi." 9
and 10; Braun, Vcrjibi-
gmg, &c. p. 170 {Bag
iSoc. 18o3).

BOTRYOSPO'RIUM,
C orda (St achy lid in m,
Tries). — A genus of Mu-
cedines (Ilyphomycetous
Fungi) aUit'd to Botrgtis,
but distinguished by the
lateral position of the spo-
riferous branches (fig. 70).
British species :

Botrrosporiiim

pulehrum.

A fertile filament

bearing fporiferoua

lateral branches.
Magnified 2(J0 diam.

B. ciijfusvm, Corda
(Stachglidium dtfftmnn, Fr., Botrgtis dif-
fusa, Greville), forms loose white tufts, a

quarter of an inch high, on decaying her-
baceous plants, especially potatoes.

B. pulehrum, Corda (tig. 70), forming
mealy patches on living or decaying herba-
ceous plants.

BiBL. Corda in Stm-m's Deutschl. Fl. iii. ;
Prachtjl. Euro}}. ScJmnm. p. 39 ; Greville,
Sc. Cn/pt. Fl. t. 126. tig. 2; Currev, Qu.
J. Mic. Sc. V. p. 117.

BOT'RY'TIS, Mich.— A genus of Muce-
dines (Ilyphomycetous Fungi), among
which are found some of the commonest
moulds of decaying vegetable substances,
and some veiy important parasitic fungi.
Corda separated the species with the fila-
ments continuous into a genus Peronosjwra
(fig. 77), from those with articulate fila-

Fig. 77.

Fig. 78.

Botrytis (Peroncjspora).
Magnified iOO diameters.

Botrytis.
Magnified 200 diameters.

ments (fig. 78). Among the remaining
forms are distinguished species of varving
habit, separated b}* some authe)rs under the ,
name of Polgactis and Ilapluria. The Po-
tato-fungus and the Muscardiue of silk-
worms are species of Botrytis, as described
below ; their natural history is further
treated of under the liead of PaeasitiC
FrNGi. The following have been described
as British species : —

B. {Ilaplaria, Lk.) grisea, Fr. Fertile
filaments simple or forked, grey, slender,
rather rigid, septate, with little heaps of
globose grey spores at the api( es and sides.
On decaying vegetables, usually on S/)ar-
ganiwn and allied plant*. Corda, Ic. Futxf.
i. pi. 4. fig. 246.

B. (Polgactis) cinerea, Pers. Fertile fila-
ments gregarious, almost simple, cinereous,
soon .'-trangulated, with white spures at-
taclied lieve and there. Not uncommon on
stems of herbaceous plants.

BOTRYTIS.

C 117 ]

BOTRYTIS.

B. (Poh/cic/is) cana, Sclnnidt. Fertile
filaments cinoreons or whitish, branched at
the apex; spores large, oval. On rut(in<i:
steins and leaves. Mucor racemosusj Biil-
Hard, t. 504. tig. 7.

B. {Pohjadis) vulgaris, Fr. (fig. 263).
Fertile filaments grey, divid.^l at the apex
into lobe-like branches, on wliich are col-
lected the globose minute spores. Common
on rotting plants. B. acinorum, Pers. Fre-
seuius, BeUr. z. Mi/c i. pi. 2 (?). Pohjadis
vult/an's, Nees, Si/st. fig. 57.

B. vera, Fr. Fertile filaments grey,
branched above, forming spikes about the
slender apices. On decaying substances,
fungi, Sec. Mucor Botrytis, Bolton, pi. 132.
fig. 3.

B. crustosa, Fr. Fertile filaments -white,
simple, tritid and verticillate ; spores glo-
bose, ternunal. On stems and Icixves.

B. citrina, Berk. Mycelium white ; fer-
tile filaments erect, articulated, branched ;
branches subcymose, and, hke the obovate
spores, lemon-coloured. On dead brandies
of cherrv-trees. Berkeley, Ann. N. H. i.
p. 262, pi. 8. fig. 12.

B. ten-estris, Pers. Fertile filaments
v^hite, quaternately divided at the tips, each
tip bearing a single globose spore. On rot-
ten .sticks. Berk. I. c. pi. 14. fig. 24 ; Sta-
chyJirlixm terrestre, Grev. So. Crypt. Fl.
ph 257.

B. Jonesii, Berk, and Br. Fertile fila-
ments erect, fa ^^^l-coloured, branched above ;
branches and branchlets divergent, mostly
opposite, the last fasciculated, the centre
always sterile and very acute; spores round-
ish, spiny. On dung. Attn. N. S. 2 ser.
xiii. pi. 15. fig. 12.

B. Tilli'fii, Desm. Fertile filaments
branched, fulvous ; branchlets very short,
whorled ; spores subglobose. On mosses
and various leaves. Desmaz. Cn/pt. Exs.
fa.sc. V. No. 226 ; Ann. cl. Sc. Nat. 2 ser. x.
308.

B. (Pero7iospo7-a) urticee, Libert, MSS.
(Berk.). Fertile filaments gi'eyish lilac,
loosely di^-ided above ; branches forming
an acute angle ; extreme branchlets simple
or forked, sometimes ciu'ved, rarely inflated ;
spores large, ovate, apex papillilbrm. On
nettle-leaves. Berk. Ann. N. H. ser. 2, vii.
p. 100.

B. {Peronospora) parasitica, Pers. Fer-
tile filaments white ; Branches ramulose ;
.spores very large, globose. Caspary has
found here cysts containing minute spores
(sporidanyia). On Cruciftrae (turnips, cab-

bages, &c.). Berkeley, JT Ho7-t. Soc. i. pi. 4
fig. 26; Corda, Ic. Funy. v. pi. 2. fig. 18
Mucor Botrytis, Sowerby, pi. 359.

B. (Peronospora) cffusa, Greville. Fertile
filaments purplish-gi ey, branched above ;
branches short, divaricate ; spores large,
oval. Frequent on the lower face of leaves
of spinach,

B. {Peronospora) curia, Berk. Fertile
filaments simple, abbreviated, denticulate
at the tips, grey-brown ; spores oval. On
Anemone nemorosa. Berk. Ann. Nat. Hist.
I. c. pi. 8. fig. 13.

B. {Peronospora) destructor. Fertile iila-
nients grey, erect, scarcely septate ; branches
alternate, the last forked, hooked, and diva-
ricated; spores obovate, much attenuated
at the base. Very destructive on species of
Allium (onions &c.). Berk. Ann. Nat. Hist.
vi. p. 436, pi. 13. fig. 23.

B. (Peronospora) Arenaricp, Berk.
White; fertile filaments dichotomous
above, divaricate-forked, not hooked at the
tips ; spores ovate. On the leaves of Are-
7iaria trinervis. Berk. ./. Hort. Soc. i. p. 31,
pi. 4. fig. 22.

B. (Peronospora) Vicics, Berk. White ;
fertile filaments sparingly branched, elon-
gate ; branchlets bifid , not hooked ; spores
obovate, apiculate. On common Vetches
(a distinct species, purple, is said to grow
on peas). Berk. /. c. pi. 4. fig. 23.

B. {Pei'onospora) arborescens. Berk.
White ; fertile filaments very much branched
above, di-trichctomous, somewhat forcipate
at the apex ; spores smallish, subglobose.
On common red-poppv leaves. Berk, /. c.
pL 4. fig. 24.

* B. {Pei'onospora) yanylio7iifor77iis, Berk.
White, in patches ; fertile filaments branched
above ; branchlets curved, dilated in gang-
lioid thickenings below the tips ; spores
small, subglobose. On lettuces. Berk. /. c.
pi. 4. fig. 25. B. ye7ninafa, Unger, Bot.
Zeit. V. pi. 6. fig. 9. Bre7nia lactucce, Regel,
Bot. Zeit. 1843, i. p. 665, pi. 3 B.

B. (Peronospo)-a) 7nacrospora, Ung. Fer-
tile filaments erect, several from the same
point, white, branched above ; spores very
large, elougate-py rif orm . On leaves of pars-
nips and other Umbelliferse. linger, Exan-
theme, pi. 2. fig. 14 R

B. {Peronospora) i7ifestans, Montagne
(PI. 26. figs. 5, 6). The Potato-fungus.
This grows in tufts on the lower surface of
the leaves, and also on the tubers of the
potato, forming white mealy spots. The
mycelium ramifies in the intercellular pas-

BOTRYTIS.

[ 118 ]

BRACHIOX.EA.

sages of the leaves, and sends out the fertile
filaments from the stomata, so that these
appear scattered among the hairs of the
epidermis; they are usually about 1-30"
high upon the leaves, branched at the apex,
septate and white. The 2 to 6 branches are
erecto-patent, acute, virgate, nodose from
numerous ehptical thickenings. The spores
in large specimens are at first globular-
ovoid, then elliptical, and finally somewhat
of the shape of a gourd-seed, with a sub-
apiculate mamilla at one end, very shortly
pedicellate at the other, of the same colour
as the filaments, chiefly white, densely
fiUed with sporules enclosed in an endo-
spore, about 1-800" long, 1-1200" thick.
These sponUes have been shown by Ue
Bary to be zoospores when fully developed,
moving about by means of two cilia.
Besides the normal spores, there are resting-
spores in many Peronosporce, which have
been described by the same author in Ann.
d. Sc. N. 1863, XX. p. 10. Artotrof/us of
Montague is probably the resting-spore of
Peronospora infestnns. Berkeley, Jn. Ilort.
Soc. i. 30, pl.^ 2-4. figs. 4-19. Botrytis
Solani, auct., var. i?. fallax, Desmazieres.
B. devastatrix, Libert ; Morren, Ann. de la
Soc. de VA(j. de Gcmd, 1845, p. 287 ; Pero-
nospora trifurcata, Unger, Bot. Zeit. v. 314,
pi. 6. figs. "1-6; AV. Smith, M. M. J. 1875,
xiv. 110 (figs.).

Botrytis Bcissiana, Balsamo, is the fungus
growing in the bodies of silkwonns, causing
the disease called Muscardine, which some-
times produces most extensive destruction
in the districts where they are cultivated.
A figure of it is given by Mr. Berlceley in
the paper on the Potato-fungus referred to
above. Many papers on it exist in the
Comptes liendus; and the whole history, with
figures, will be fouud in Robin's Vcyetaux
Parasites, p. 560.

Botrj/tis lateritia, Fr., not uncommon in

the hollows of decaying potatoes, beet-root,

&c., appears to be a form of Acrodahiymus

parasitans, Corda. See Acrostalagmus.

The genus Botrytis, like many other

genera, has been divided and subdivided

till the genus itself has almost vanished.

It is restricted in the ' Outlines of British

Fungology ' to those species which have

septate, hyaline or coloured threads, Avith

terminal spores, as B. Tilletii, citrtna,Jo7iesii,

and terrestris. Several of the so-called

species are states of Ascomycetous Fungi.

See Tulasne, Carpohyia, vol. iii.

BiBL. As given under the species. Fries,

Summa Veget. p. 490 ; Berkeley, Crypt. Bot.
p. 307.

BOUGAINVIL'LIA, Lesson.— A genua
of marine Hydroid Zoophytes, family
AtractylidfB.

Char. Stem branched, rooted by a fili-
form stolon ; pol^-pes fusiform ; a single
wreath of fihform tentacles around the base
of the conical proboscis. 3 British species.
BiBL. Ilincks, Hydr. Zoopli. p. 108.
BOWERBAX'KIA, Farre.— A genus of
Infundibulate Polyzoa (Bryozoa), of the
suborder Ctenostomata, and family Yesicu-
lariidae.

Distinguished by the matted and creeping
or erect and irregularly branched polypidom
(polyzoarium), the tubular densely clus-
tered cells, the eight to ten tentacles, and
the strong gizzard.

B. imhricata (PI. 18. fig. 19), the only
species, has the cells ovate or ovato-cylin-
di'ical, in dense clusters irregularly scattered
on the polypidom.

Parasitic on other Polyzoa, Polypi, and
Algae. Polypidom in the young state creep-
ing and matted, and formerly regarded as a
distinct species {B. densa) ; in the adult
condition forming bushy confervoid flaccid
tufts, an inch and a half high, much and
irregularly branched. Branches smooth,
transparent and hollow, cells aggregated on
one side.

It forms a favourable object for the study
of the structure of the Polyzoa, on account
of its transparency.
Four other species.

BiBL. Johnston, Br. Zooph. 377 ; Farre,
Phil. Tr. 1837, 891 ; Gosse, Mar. Zool. ii.
p. 21 ; Hincks, Poh/zoa, 518 ; Repiachofl^,
Zool. Anz. ii. 1879, 660 {Jn. Mic. Soc. 1880,
iii. 238 : embryol.).

BOX. — The wood of the box-tree, Bu.rus
sempervirens, L. (Nat. Ord. Euphorbiaceoe,
Dicotyledon), is remarkable for its hardness,
offering a great contrast to that of Bomhax
and the like. See "Wood.

BRACIIIONJi'A.— A family of Rota-
toria.

Char. A carapace (testida) present ; rota-
tory organs two, simple.

The rotatory organ sometimes appears
to consist of five parts, three median and
two lateral. The two larger lateral ones
only are true rotatory oi'gans, the cilia
of the median ones remaining extended
without motion during the action of the
others. Tlie carapace resembles that of a
tortoise.

BEACHIONUS.

[ 119 ]

BRANCIIIPUS.

Genera :

Eye-apot3 absent ; foot forked Nofeus.

( J foot absi-nt Anuria.

. I °°e I f,,^|. f^,j.].p,:, Bmckionus.

Eye-spots present^ ^ j.^^^ ^^j^^^^^ Fompholyx.

^two -^ j.^g^ styliforin .. Pterodina.

See IIydrocora and Dipodina.

BRA'CHIONUS, Hill.— A genus of Ro-
tatoria, of the family Bracliionaja.

Char. A single eye-spot at the back of
the head ; foot forked.

The anterior margin of the carapace is
furnished with teeth, as in some species is
the posterior margin also.

B. amphiceros (PI. 43. fig. 8). Carapace
smooth, furnished both at the anterior and
posterior margin with four teeth ; aquatic ;
length 1-70".

B. ruheiis. Carapace smooth, with six
acute teeth in front, and rounded posteriorly;
body reddish ; aquatic ; length 1-50" : teeth,
PI. 43. fig. 9.

Eleven other species have been described;
some of them freshwater, others marine.

BiBL. Ehrenb. /»/".; Dujardin,/Mf.; Gosse,
Ann. N. H. 1851, Viii. p. 202; Cbhn, Sii^.
8,- KnUih. Zeit. vii. p. 459.
BRACHYCLA'-
DIU]\[,Corda. — A genus
of Dematiei (Hyphomy-
cetous Fungi), not se-
parated by any marked \^';
characters from Den-
DTtYPHiUM ; forming a
delicate mould on dry
stems of herbaceous
plants. The filaments
and branches are formed
of squarish cells, swollen
so as to produce a moni-
liform appearance, the
walls being thick and
coloured.

The so-called species

are probably stages of An crert, filament with
A«r>nnivppfmi<? Fiino-i fertile branehes.

ASCOm^ Cetous r ung l. Magnified 200 diame-

B. jyenicillatum, Lorda, ters.

is said to extend over
stems, sometimes in tracts a foot long ; the
filaments and branches are blackish, the
spores white (fig. 79).

B. Tliomasinum has been found in amber.

BiBL. Corda, Ic. Fung. ; Fries, Summa
Veq. p. 504.

BRACHYCO'LUS, Buckton.— A genus
of Aphidye.

B. stellarice. Body mealy, very long and
narrow. On Stellaria Jwlostea and HuJcks
mollis.

BrachycladI um peni-
cillatum.

BiBL, Buckton, Aphides ( Ttay Soc ), ii.
p. 146.

BRA'CIIYODUS, Nees.— A genus of
Leptotrichaceous Mosses, separated from
Gyninostommn or Weissia of some authors.

BiBL. Wilson, Bn/ol. Brit. p. 52.

BRACIIYSTE'LIUM, Reichb.— A ge-
nus of Orthotrichaceous Mosses.

Braclujstelium 'polyphylhim, IIscli., =
Pti/chondtrium pohiphyllus, Br. and Sch.

BiBL. Wilson, Bn/'ul. Brit. p. 173.

BRACHYTHE'CIUM, Br. and Sch.,=
Hypnum.

BiBL. Wilson, Bryol. Brit. p. 337.

BRA'DYA, Boeck.— A genus of Ento-
mostraca (Copepoda).

B. typica. Anterior autenuiB very short,
7-jointed. Scilly Isles.

BiBL. Brady, Copepoda (Ray Soc.) ii.
p. 16.

BRADYCINE'TUS, Sars.— A genus of
Eutomostraca, of the order Ostracoda (sec-
tion Myodocopa) and family Cypridinidee.
Characterized by the 2-branched lower
autenniB, and the one pair of feet. B. brenda
= Ci/pridina brenda, Baird; B. Macandrei
= Ci/p. Mac. B.

BiBL. Brady, Linn. Trans, xxvi. p. 466.

BRAIN. See Nerves.

BRAl'NEA, Hook.— A genus of Gram-
mitidete (Polypodiaceous Ferns), with con-
tinuous sori along transverse veins near
the midrib, produced along the veins to-
wards the edge of the frond.

The single species, B. insiynis, is found at
Hong Kong &c.

BiBL. Hooker, Si/n., p, 390.

BRAN. See Corn.
BRAN'CHM^. — This term is synonym-
ous with gills. The latter term, however,
is usually applied to the aquatic respira-
tory organs of fishes, whilst those of other
animals retain the name of branchife. Their
structure is described with that of the re-
spective classes in which they occur. See
also Ephemera and Libellulid^.

BRAN'CHIPUS, Schfeffer {Chiroce-
phalus). — A genus of Eutomostraca, of the
order Phyllopoda, and family Branchipo-
didae.

Char. Abdomen prolonged in the form
of a tail, composed of nine segments or
joints, the end joint -^^dth two well-deve-
loped plates or lamellar appendages ; supe-
rior antennae, in both sexes, slender, fili-
form, and many-jointed; inferior antenniB
in the male large, curved downwards, two-
jointed, furnished at the base with fan-

BRAND.

[ 120 ]

BRONCIIOCERCA.

shaped and digitiform appendages ; in the
female stout, short, somewhat acute, slightly
curved, and not furnished with appendages
at the base.

B. stMfinalis (PI. 20. fig. 3). An inch in
length ; tinged with red.

This beautiful animal is found in stagnant
water, as the ditches and deep cart-ruts on
the edges of woods and plantations.

-B. rtibricaudatus, Kl. Ovarian sac and
tail-fork red ; the former long, cylindrical,
terminating in a curved prickle.

In rain-water, atlvossier (Red Sea).

BiBL. Baird, Brit. Entuin. p. 39 ; Ivlnn-
zinger, Sieb. 4'- Klill. Zeitsch. xvii. p. 23.

BRxAND. — A disease of Cereal Grasses
and other plants, depending on Fungi. See
Blight.

BREAD. — The interest of the micro-
scopic examination of bread depends chiefly
on the impurities it may contain, or the
peculiar Fungi-development in it during
decay. The commonest intentional adul-
teration of bread is the addition of mashed
potatoes to the flour ; but it must be re-
membered, that potato-yeast is somotimos
used to produce the fomentation of the
dough. Tlie cells of the potato are retulily re-
cognizable in bre;i,d after the starch has been
dissolved and washed away. Tlie adul-
teration of the flour with other meals, as
corn-flour, rice, beans, &c., is easily ascer-
tained before it is made up ; but the baking
greatly aflects the form of the starch-gra-
nules. See Starch.

The spores of the parasitic Fungi of wheat
(UiiEDiNEi, UsTiLAGiNEi), poUen-graius,
and other vegetable bodies are occasionally
met with as accidental impurities, and are
present in large nimabers in inferior and
" damped " flours.

The fermentation of bread depends upon
the development of the Yeast fungi in the
dough : an account of this will be found
under that head, and Fermentation.

JNlouldy bread presents various microscopic
fungi in a mature condition, some evidently
the fruit of the yeast-plants, Fenicillium,
]\TuroR, &c. ; others, like the so-called
' blood on bread,' appear to be peculiar
states of the vegetative structure of the
same Fungi.

liiBL. That of Anui.TE.RATiON ; and
Coulier, ]\J<nu«'l ^^-c. ; Rubin, Micr. p. 922.

jniET'TIA, Dyster.— A genus of Cliei-
loslomatous Polyzoa (Ih-yozoa), family l']u-
cratiida). 'J'wo species : found between tide-
marks, and in di edgings.

Briarea ponicillata.

M.igniftod 200 dia-
meters.

BiBL. Tlincks, Polyzoa, p. 27 ; ' Dyster,
Qu. Mic. Jn. 1858, vi. p. 260.
BREUTE'LIA, Br. and Sch.,= Bartra-

MIA.

BiBL. Wilson, Bryol. Brit. p. 283.

BRLA'REA, Cord'a.— A genus of Muce-
dines (Ilyphomycetons
Fungi), nearlv J'elated to
Penicillium, Asperf/i/iKs,
and Moni/ia, distinguished
f romthe first and last by the
moniliform rows of sp;:)res
arising, directly, in a ter-
minal tuft, while the erect
fertile filament is not ex-
panded into a capituluin
to bear them, as is the case
in AsperyiUus. British spe-
cies : —

Briarea penicilJata (fig.
80), (Mojiilia, Fries, ^-l.s/^c^r-
(/illus, Greville). The erect
filaments are simple and
geniculate, the spores hya-
line, forming long nodding
moniliform rows. It is of dark grey coh;;ur,
and is found on damp grass, mouldy hay,
straw, &:c.

BiBL. Corda, Ic. Fimq. v. 16, and in
Sturm, Dvutschl. Flor. ii. pi. 6 ; Greville,
Sc. Cnipt. Fl. t. 32 ; Berk., Hook. Br. Fl.
345.

BRIGIITWELLIA, Ralfs.— A genus of
Diatomacese.

Char. Valves disk-shaped, with a large
granulated centre, separated from a broad
punctate limb by a ring of oblong cells.

B. coronata, Mic. Tr. viii. p. 95, pi. 5.
f. 6; B. elaharata, ibid. 1861, i. p. 73;
B. Johnsoni, ibid. 1806, vi. p. 4.

BiBL. Ralfs, Pritchard's Infns. p. 940.

BRINE- WORM. See Artemia.

BRISTLE. See Hairs.

BROMELIA'CEyE.— A family of Mono-
cotyledons (Flowering Plants), of which the
Pine-apple, Ananas or Ananassa, is the
most familiar example. Tliis is interesting
microscopically from the scurfy character of
the epidermis of the leaves, dependent on
peculiar cellular scales. The cells of the
epidermis are of very elegant form (PL 47.
fig. 15) ; and the fibres of the leaf are manu-
fnctured into very fine muslin. See Scales,
Epider^iIis, and Fibres.

BRONCHI. See Lungs.

BRONCIIOCER'CA.— J/oHO<WT« with
the caudiform foot cleft at the end. Five
species have been described; but it appears

BROOKE'S APrAPtATUS. [ 121 ]

BRYOBIA.

that they do not difler by well-marked dia-
racters i'loiu tlie spoc-ies of Monucercn.

13IBL. Wcrueck, Bcr. Bed. Ak. 1841,
377.

BROOKE'S APPARATUS. Intro-
duction, p. xxi.

BRUCHIA'CE/E.— A family of inoper-
culate Acrocarpous Mosses, gregarious or
Cfespitose and terrestrial, in which the fruit-
stalks sometimes appear lateral, through
arising from innovations. The stems dwarf,
either simple or branched by innovations ;
the leaves lanceolate or awl-shaped from a
more or less oval base, composed of paren-
chymatous cells, larger and sometimes lax
at the base of the leaf, smaller and squarish
toward the apex, and furnished with a flat-
tened broad nerve (fig. 49), and standing up
like bristles ; the pericha^tial leaves broader
at the base and sheathing ; all of firm mem-
branous character, shining and smooth.
Capsules oval or globose, mostly straight-
beaked ( iig. 50). British genera : —

Arc/tidunn. Calyptra completely en-
closing the (globose) capsule, biu'sting above.
Inflorescence moncf'cious, bud-shaped.

Astomum. Calyptra dimidiate. Capsule
equal. Inflorescence either monoecious,
gemmif orm and axillary, or witb the anthe-
ridia and archegones together.

BRU'OHUS, Linn.— A genus of Coleo-
pterous Insects.

B. jnsi is a common small beetle ; black,
mottled with white. The larva feeds upon
peas. Several other species.

BiBL. Stephens, Brif. CUeopt. p. 204;
Boisduval, L'Entomol. Horticole, p. 1-57.
BRU'CIA. See Alkaloids.
BRYA'CE^-E.— A family of operculate
Mosses, acrocarpous, or by innovation pleu-
rocarpous, with lan-
ceolate, oval, round,
or spathulate leaves,
composed of cells pa-
rallelogrammic below,
rhomboidal - paren-
chymatous above,
more or less dense,
with much chloro-
phyll or a persistent
primordial utricle, or
at length empty, very ^|
smooth. Capsule more '17- ,• . , • .^.■,

, J^ , , Miehchoferia nitida.

or less pear-.shaped, ,, ^, ^

d. *^ 1 S- ' leeth Irom the peiistome.

avate, oval or cylm- Magnified 150 diameters.

drical. Mith a hemi-
spherical or conical operculum, erect, nod-
ding or pendulous. External peristome,

when present, soft, lamellose, internal
membranous. British genera : —

Mii'lichoferia. Calyptra conical-dimi-
diate, split at the side. Peristome wanting
or simple, then of sixteen equidistant, fili-
form, liattish, articnlat(>d pale teeth, some-
times placed on a sliort, sulcate, reticulate
basilar mi>mbraue (fig. 81). Capsule late-
ral, with a double annulus.

Orthodontium. Calyptra smallish, hood-
shaped, fugacious. Peristome arising below
the orifice of the capsule, double; external :
of sixteen lanceolate-subulate teeth, like
those in Bryuin ; Avhen dry, deflexed below
the orifice of the capsule, when moistened,
erect; internal: cilia alternating with the
external teeth, half as long or about equal,
filiform, from a short, somewhat keeled
membrane. Capsule annulate or exannu-
late, with a lougish collum.

Bn/um. Calyptra dimidiate, smallish,
hood-saaped. Peristome double (fig. 82) ;

Fig. 82.

Bryum intennedium.

A portion of the peristome.
Magnified 150 diameters.

external of sixteen lanceolate, soft, yel-
lowish equidistant teetli, flat on the back
and transversely trabeculated, with a flexu-
ous longitudinal line in the middle, lamel-
late within, hygroscopic ; internal a large
delicate membrane with sixteen keels, pro-
duced into more or less perfect lanceolate
teeth, often with intermediate cilia, some-
times without. Capsules mostly annu-
late.

BiBL. See Mosses.

BRYO'BIA, Kocli.— A genus of Aca-
rina, family Trombidina.

Char. Legs 0-jointed ; fore legs longest ;
eyes near the hind angles of the cephalo-

BRYOPSIS.

[ 122 ]

BUDS.

thorax ; abdominal margin studded with
short, sorae\Yhat triangular sparse papillae.
B. speci()>'a.

BiBL. Kdch, Uebersicht, 01 ; Murray,
Ec. Ent. 117.

BRYOP'SIS, Lamouroux.— A marine
genus of Siphonete (Confervoid Algfe), of
■which the British species form beautiful
green, somewhat elastic, feathered silky
tufts, from 1 to 4" high upon rocks or upon
other Algae, in tide-pools. The whole axis
and proper branches of each plant consist of
one large ramified cell, the cavity being
continuous throughout, the membranous
wall rather thick, and somewhat gela-
tinous externally ; the branches are naked
below, but clothed above by small raniuli,
arranged like leaves, distichously, spirally,
or irregularly. The main axes and branches
grow indefinitely by development of the
apices; the rarauli are limited in their
development, and they are ultimately shut
off by septa, at last falling oft' by the cir-
cular rupture of their wall, just above theii"
point of origin.

When examined early, the ramuli are
found to have their walls lined with largish
elliptical green grains, each of which has at
first a round light central body, colourable
blue by iodine when fully formed (starch-
corpuscle). The branches exhibit the phe-
nomenon of reproduction, in irregular order,
in the following way. The green bodies on
their walls multiply by subdivision, and
increase in size and number until they com-
pletely fill the tubular cavity of the ramule,
pressing upon one another so as to form a
compound dark-green mass. A peculiar
swarming movement is next observed in
the green bodies, which increases more and
more: and, the parent tube opening by a pore
near its apex, the green bodies escape as
elongated pear-shaped zoospores or active
gonidia with cilia, according to Thuret,
two and four in B. hypnoidcs, only two in
B. plumosa. The successive emission of
the gonidia from the various tubes of one
plant occupies several days.

After the gonidia have come to rest, they
acquire a spherical form, and gradually in-
crease in size ; at the end of a month or six
weeks their diameter is twice or thrice the
original dimensions ; and then they begin to
elongate into a tube similar to the pisreut.
Agardh found them elongate, either in one
direction or in two, at first ; but one end
soon swelled into a thickened organ of
attachment, while the other began about

the sixth week to branch, British spe-
cies : —

B. plumosa, Huds. (PI. 4. fig. 19). Deep
gi-een, 1 to 4 inches high, more or less
branched ; the branches pinnated with sub-
opposite distichous or rarely irregular ra-
mules. IIarvey,3/«r. Algce, 2ud ed. pi. 24 B ;
PInjcol. Brit. pi. 3 ; Greville, Alyce, pi. 19 ;
Engl. Bot. (Ulva plumosa), 2375.

B. hypnoicles, Lamour. YeUow-gi'een,

2 to 4 inches high, more slender and more
branched, branches repeatedly divided, ra-
mules irregularly scattered, somewhat pin-
nate, more or less dense. Harvey, Pht/a.
Brit. pi. 119.

BiBL. S^'stematic, as above, and Klitzing,
Sp. Alg. p. 490 ; Physiologv, &c., Agardh,
Ann. d. So. Nat. 2 s^r. vi. 200, pi. 12 ; Xa-
geli, Zeits. wiss. Bot. 1844-46 {Ray Sac.
1845, 269, pi. 6. figs. 11, 12; 1849, 97, pi. 2.
figs. 1-3) ; Ken. Ah/en-Si/steme, 1847, 171,
pi. 1. figs. 44-56 ; Thm-et, A^m. d. So. N.

3 ser. xiv. 8, pi. 16. figs. 1-6 ; Braun, Verj.
137 {Bay Soc. 1853, p. 120) ; Pringsheim,
Monatsber Berl. Alcad. 1871; Sachs, Bot.
275.

BRY'OZO'A. See Polyzoa.

BRY'UI\1, Dill. — A genus of operculate
Mosses, usually acrocarpous, containing a
large number of British species, even in its
restricted condition.

Among the most common of these are
B. nutans (fig. 467), cernnum, intermedium,
capillare, ccespiticium, &c. Many of the
older species are now included under
Mnium.

BiBL. Wilson, Bryol. Brit. p. 221.

BUC'CINUM, L.— i?. undulatum, the
common Whelk. The tongue forms an
interesting microscopic object.

BUDS. — The buds of plants form inter-
esting objects of microscopic investigation
on many accounts, — first, in tracing the de-
velopment of the organs, and also of the
tissues of which these are formed; secondly,
on account of certain temporary structures
which they exhibit. The thick epidermis
of the scales of the winter-buds of ordinary
trees, as of the ash, &c., is a very favour-
able object for sections to show the charac-
ter of this tissue when highly developed.
The internal soft scales and young leaves of
very many of these winter-buds, as well as
other buds of herbaceous plants, are clothed
with glandular hairs, which disappear wlieu
the buds are expanded ; and these often
afford advantageous material for studying
, cell-development. See CiEiiMiE.

BUG.

[ 123 ]

BULBOCH^TE.

BUG. See Cimex.

BU'GULA, Okeii {Cellularia part, John-
ston).— A genus of Infuadibulate Polyzoa
(Bryozoa), of the suborder Cheilostomata,
and family Bicellariida?.

Distinguished by the elliptical closely
contiguous cells in two or more rows, the
very large oritice with a simple not thick-
ened margin, and the stalked, jointed, fre-
quently blue or red avicularia.

B. Jiahdiata. Cells in many rows, ob-
long, truncate at ends, with one or two
spines at upper angles ; orifice extending to
the base ; avicularia ou the sides of the cells
capitate, surface smooth ; ovicells cucullate,
with a very wide orifice.

B. avicularia {Cellularia avic, Johnston).
Cells in two rows, elongate, contracted
below ; oritice not reaching quite to the
base, obovate ; with two spines on the outer
side, and one on the inner above ; avicularia
lateral, capitate, surface granular or areo-
late ; ovicells superior, subglobular : orifice
small. Deep water.

B. 2^l"»iosa. Cells elongate, narrowed
below, with a spine at upper and outer angle ;
orifice as wide a? the cell above, elliptical
below ; avicularia capitate, close to outer
margin of the orihce ; ovicell superior, glo-
bular.

B. Murrayana (Flustra 3Iur., Johnst.).
Cells in many rows, narrowed about the
middle and below ; orifice oval, with one to
four incurved marginal spines on the outer
and one on the inner edge ; a strong hollow
spine on each side of the top of the cell, and
a capitate avicularium on the front of some
of the cells below the orifice. Very rare.

Bir.L. Busk, Mar. Polyzoa {Br. Mus.),
43 ; Johnston, Br. Zooph. ; Hincks, Polyzoa,
73.

BULBOCILE'TE, Ag.— A genus ofCE-
dogonieae (Confervoid Algte), distinguished
by the branched habit, and by the cells re-
sembling bristles with a bulbous base situ-
ated at the tips of lateral shoots. They
form villous tufts 1-4 to 1-2" high on fresh-
water plants in lakes and pools.

The cells of the main filament multiply
in the same way as those of Gi]DOGONiu.\r,
under which head the process is minutely
described. The parent-cell breaks by a cir-
cumscissile dehiscence to allow the expan-
sion of the two new cells. The bristles which
are formed at the upper ends (alternately
on each side of the filament, fig. 83) like-
wise break out from a slit in the cell from
which they arise. The bristle is sometimes

sessile on the cell from which it arises ;
sometimes multiplication takes place at its
base, so that one or more cells are inter-
posed ; the bristle is always the oldest part
of the branch.

These plants are
multiplied by zoo-
spores, and by rest-
ing-spores formed
after fertilization
by the contents of
antheridial cells.
The zoospores are
formed from the
whole contents of a
or oval
produced be-
tween the bristle-
cell and the cell on
which it is attached,
which dehisces bv

globular
cell

Bulbochoete setigera.

Portion of n fllamentwith a

8porii'erou3 cell.

Magnified 150 diameters.

a circular slit, causing the upper part with
the bristle to separate, and allowing the
single zoospore, crowned by a wreath of
cilia (as in CEdogonium), to escape into the
water, where it moves actively for a time,
acquires a cellulose coat, and then germinates
into a new filament. We have not space to
give the details of the development of the
parent-cell of the zoospore, which, however,
are very interesting'.

The resting-spores are formed, in the first
place, somewhat in the same way and in the
same situations as the zoospores ; but the cell-
contents do not escape. An orifice is formed
in the wall of the parent-cell, through which
the spermatozoids coming from the anthe-
ridia penetrate. The spore-mass then be-
comes encysted ; and its contents are changed,
the green colour arising from the presence
of chlorophyll giving- place to a brown tint.
The resting-spore ultimately escapes by the
rupture of the parent-cell (oof/otiium, Prings-
heim) ; and in its germination (in the fol-
lowing season) the contents are developed
into four zoospores, which escape from the
spore-membrane and grow up singly into
new plants (PI. 5. fig. 22).

The history of the antheridia of the (Edo-
gonieoe is somewhat complicated. In the pre-
sent genus, a few short cylindrical cells are
developed underneafh the bristle-cell, either
on special branches or ou the sporangial
branches, between the parent-cell of the
spores and the bristle. These cells break
by circumscissile dehiscence, and discharge
their contents in a form exactly resembling
the vegetative zoospores, but much smaller.

BULBOTPJCHIA.

[ 124 ]

BURSARINA.

These ultimately come to rest, and com-
monly attach themselves to germinate upon
tlie walls of the parent filament, often on
the outside of the mother cell of the spore.
When they germinate, they become short
filaments composed of one, two, or several
cells, in each of which is developed one or
two spermatozoids, which are minute glo-
bular active bodies with a wreath of cilia,
almost colourless, but in other respects re-
sembling the much larger zoospores. These
spermatozoids escape by the cells breaking
across, and have been observed to enter the
oriliees in the walls of the parent-cells of
the spores and effect the fertihzation.

Pringsheim has described a number of
species, characterized by the form of the
sporange and the unicellular or multicellu-
lar condition of the anlheridial plants, and
by the relative dimensions of the organs.
AVe are not assured of the value of these cha-
mcters, and confine our list to one species.

B. setigera, Ag, (fig. 83), is a common
plant, and is variable in the relative length
and diameter of its cells, on which ground
Kiitzing has separated a B. minor, where
the diameter is equal to or greater than the
length. Hassall, A/c/. pi. 54. tigs. 1-4 ; Dill-
wyn, Conferv. pi. 59.

B. Prhujsheimiana, Archer. Qu, Mic, Jn.
186G, p. 122.

Rabeuhorst describes 16 species.

BiEL. Alex. Braun, Verjiing. (Bai/ Soc.
1853); Hassall, A7in. N. H. xi. 36; Ahj.
209, pi. 54; Decaisne, ^«ra. d. Sc.Nat.2 ser.
xvii. 335, pi. 14. fig. 5 ; Kiitzing, Sp. Ah/.
429; Pringsheim, Berlin Ber. 1855 (Ann. jV.
H. ser. 2. xv. 346; Qu. Mic. Jn. iv. 131,
185G) ; Ja/irh. f. tviss. Bot. i. 11, 1857 ; Ue
Bary, Mus. Scnckenbera, 1856, 29 ; Rabeu-
horst, Fl. Ah/, iii. p. 357 ; Sachs, Bot. 281.

BULBOTRICII'IA, K.— A doubtful ge-
nus of Algse.

Char. Filaments indistinctly jointed,
colourless, subcartilaginous, branched ;
branches bulbous at the base, tumid at the
apex, forming sporangia.

B. hofri/dides. Forming a hoary-green
powdery stratum ; sporangia green. On
roofs.

B. peruana. On rocks.

BiBL. Kiitzing, Tab. P/n/c. iv. 1^.22 ; Ra-
benhorst, Fl. Ah/, iii. p. 374.

BULIMI'NA", DOrb. — An important
group of Foraminifera, so called from their
Bulimine shape, due to an increasing and
spiral series of one, two, and e^en three
chambers, close-set, with their apertures

towards the umbilical axis. The aperture
is an infolded notch of the septal face, and
usually oblique. The shell hyaline in the
young state, coarser in the adult. Many
fossil specimens are arenaceous ; these come
under Afa.rojj/iraf/minin, Reuss. The va-
rieties are infinite, both recent and fossil,
and the names numerous. The oldest is
found in the Trias. B. Preslii, Reuss, is
typical. B . pupoidcs (PI. 23. fig. 46) is a
common Atlantic furm.

BiBL. irOrb. For. Fos. Vien. 61 ; Wil-
liamson, Br. For. 61 ; Carpenter, Introd.
For. 194.

BUXT. — A disease of Cereal Grasses,
kc, depending on Fungi. See Blight,

TiLLETIA.

_ BURSA'RIA, Ehr.— A genus of Infuso-
ria, of the family Bursariua.

Ehrenberg described fourteen species.
They are mostly found in stagnant fresh
water ; some in the intestines of the frog,
Nais, &c.

B. vernalis (Pano/)Iir>/s, D., Frontonia, CI,
& L.) (PL 30. fig. 19), Body ovate-oblong,
turgid, green, rounded at each end, sonn—
what narrowed posteriorly, the mouth placed
behind the anterior third or fourth of the
body ; fresh wat. ; length 1-130 to 1-110".

B, ranarum (Opalina ran.) (PI. 31. fig,
47). Body ovate, lenticular, compressed,
large, white, the dorsal and ventral surfaces
keeled, anterior part subacute, often trun-r
cate posteriorly,- mouth inferior, near the
anterior pointed end; length 1-210 to 1-70",
In the intestines of the fi-og.

B. enfozoon, Ehr., which is found in the
rectum of frogs, is Balantidiiim entoz. of CI.
and Lachm.

CI. and Lachm. admit only 1 species :

B. decora. Body urn-shaped, with a long
convolute nucleus, and very numerous con-
tractile vesicles, scattered through the par-
enchyma. Berlin.

The species of B. (Ehr.) are referred to
other genera.

BiBL. Ehrenb. Inf. ; Bnj. Infm. ; Stein,
Infux. Fidwiclu'l. ; Clap, and Lachm. Inf.
p."25] ; Kent, Inf. p. 574.

BURSA.1II'.\A, i)uj.— A family cf In-
fusoria.

Char. Body very contractile, of variable
form, usually oval, ovoid, or obloug, ciliated
all over ; a large mouth with cirri forming
a row or part of a spire.

Claparede and Lachmau divide the family
thus : —

BUSKIA.

[ 125 ]

BUXBAUMIA.

StzntorinA (subfamily). A carapace, at least at one period of liCe ; anus anterior.
Body not truncate in front.

"jiuecal spire borne on a narrow pvoeops Ch(BtoKpira.

Buccal spire borne on a broad bilobed membranous expansion Freia.

Body truncated in front by a broad siu-face bearing the buccal cirri on it.s circumference Stenlor.

BURSARINA (subfamily) proper. No carapace ; anus posterior.
Watch-glass organ absent.

No row of cirri within the buccal fossa.
Front not projecting.

Body truncated in front by an oblique surface with buccal cirri at its circumference Leucophrys.

Body not truncate in front.

Anterior bundles of cirri absent from buccal fossa.
No cirri on the right side.

Body linear Spirosfomum.

Body not linear JPlagiotoma.

Bordered with cirri on the right side also.

Body elongate, of uniform breadth Kondjlostoma.

Body globular, narrowed in front Balantidium.

Buccal fossa very large, with two anterior bundles of cilia distinct from the buccal cirri Lembadium.
Fore part iirojecting beyond the buccal fossa.

Po3sa oblique Metopus.

Fossa not oblique Froulonia.

Buccal fossa funnel-shaped, with a row of strong cirri Bursaria.

A watch-glass-shaped organ at the side of the mouth Ophryoglena.

Kent's arrangement differ.? from this, and
includes several new genera, 21 in all.

BiBL. Duj. Infus. ; CI. and Laclim. Inf.
p. 211; Kent, /«/. p. 574.

BUS'KIA, Aider.— A genus of Cteno-
stomatous Polyzoa (Bryozoa).

B. nitens. On Hydroida, &c.

BiBL. Ilincks, Polyzoa, p. 631.

BUTTER.— The detection of the adulte-
ration of butter is rather a matter of che-
mistry than of microscopic investigation.
But Michels points out that the spurious
butter (oleo-margarine) exhibits numerous
free stellate or feathery crystals, often also
fragments of animal tissues ; while true
butter presents a iraiform appearance of
fatty globules, and is perfectly free from
any' crystalline forms except those of_ chlo-
ride of sodium or common salt. (Michels,
Amer. Jn.Micr. 1878; Jn. Mic. Soc. 1878, i.
p. 378.)

BUTTERFLIES. See Lepidopteea.

BUXBAUMIA'CE/E.— A familyof oper-
culated Acrocarpous Mosses, of very dwarf
stemless habit, arising from a minute tuft
of radical filaments (figs. 84, 86, &c.). The
leaves are small and flat, composed of few
minutish, hexagonal or polygonal paren-
chvmatous cells, emptv, destitute of chloro-
phyll (fig. 86). The capsule (fig. 87), sealed
on an elongated, thick, fleshy and very
scabrous stalk, is more oblique than in any
other Mosses, very ventricose on one side,
obliquely erect oii the other (dorsal) side,
cup-shaped at the base, articulated on its
stalk, fungoid in general habit, with an
obtusely conical straight operculum, and a

peristome (fig. 93). Inflorescence monoe-
cious. Brit, genus :

BUXBAU'MIA, IlalL— A genus of Bux-
baiuuiacefe (Acrocarpous Mosses), repre-
sented in Britain by B. apkt/Ua, a plant of
remarkable character. The annulus, which
persists after the operculum has fallen, re-
sembles a third, outer circle of peristomal
teeth (fig. 93) ; the real external peristome is
closely applied upon the inner, which forms
a truncated cone, slightly twisted when dry.
When ripe, the wall of the oblique capsule
(fig. 88) gives way at one side, falls oft' and
exposes the spore-sac (fig. 89) , which bursts
to discharge the spores. The columella
(fig. 94) is very large ; and the operculum is
attached to its summit. The antheridia are
oval cellular bodies opening by the separa-

Fig. 84.

Buxbaumia aphylla.

Fig. 85.

Fig. 86.

Fig. 84. A male antheridiiferous plant, magnified 40
diameters.

Fig. 8.5. An antheridium burst and discharging sper-
matozoids, magnified 100 diameters.

Figs. Sti, 90, and 91. Ar^'hegoniiferous plant, in differ-
ent stages, magnified 40 diameters.

BYTHOCYTIIERE.

[ 126 ]

CABEREAD.E.

tion of the cells like teeth above, to emit
grumous masses of spermatozoids (tig. 80).

B. indusiata has been found at Aboyne,
in Aberdeenshire, by Prof. Dickie.

BiBL. Bruch and Schimper, Bri/ol. Europ.
part i. ; Wilson, Bnj. Brit. p. 198.

Buxbanmia aphylla.

Fig. 87. Fig. 88. Fig. 89.

Buxbaumia aphylla.

Fig. 90. Fig. 91. Fig. 92.

Fig. 87. A ripe capsule, magnified 15 diameters.

Fig. 88. A plant iu which the capsule has burst and
lost the spore-sac, &c., magnified IS diameters.

Fig. 89. Spore-sae exposed by removal of the wall of
the capsule, showing the filaments by which the spore-
sac is suspended within the latter ; magnified 40 dia-
meters.

BYTHOCYTHE'EE, Sars.— A genus of
Eutomostraca (Ostracoda), fam. Cytheridae.

Distinguished by the toothed mandibles,
the 4-iointed lo\s'er, and the 7-jointed upper
antennfE.

3 British living species : B. sim]ilex, B.
constricta, and B. fiirc/ida.

BiBL. Brady, Linn. Tr. xxvi. pp. 393,
450.

BYTHOTREPIIES, Leydig.— A genus
of Entomostiaca, ord. Cladocera, fam.
JXaphniadas. Allied to Polyphenms and
Evadne.

B. lonf/imamis. Caudal bristle t^vo or
three times the length of the body. Found
in Scania.

BiBL. Leydig, Z)(7/j7/7i2V/. 244; Ann. N. H.
18G2, Lx. p. 130.

Fig. 92. A young fertile plant elevating its sporange
coTered by the calyptra, magnified 15 diameters.

Fig. 93.

Fig. 94.

Fig- 93. Mouth of capsule, with double peristome and
recurved persistent annuhis; magnified L'O diameters.

Fig. 94. Columella with adherent operculum, both
capsule-wall and spore-sac having been removed;
magnified 60 diameters.

c.

CABE'REA, Lamx.— A genus of Infun-
dibulate Poh'zoa (Bryozoa), of the suborder
Cheilostomata, and famih' Cabereadse.

Distinguished by the unjoiuted polypi-
dom, with narrow branches ; the cells in
two or three rows, \\\i]\ large vibracula
(whips) or sessile avicularia at the back,
placed obliquely in two rows. Two British
species.

C. Hooheri ( CeJhdaria Hook., Johnston).
Cells rounded, diverging, and projecting.
Rare.

BiBL. Johnston, Br. Zooph. 338; Busk,
Mar. Poli/z. 37 ; Iliucks, Polyzoa, 57.

CABE'READ.E.— A family of Infundi-
>

CABINET.

[ 1-^7 ]

CALTCIUM.

biilate Polyzoa (Biyozoa), of tlie suborder
Cbeilostomata.

Distinguished by tbe unjointed polypi-
dom, the narrow branches, the cells in two
or more rows, with vibracula (whips) or
sessile avicularia at the back. Genera :

Caheren. ]iack of branches covered with
large vibracula.

Amastujia. Vibracula absent. Not
Britisli.

BiBL. Busk, {Brit. Mtis.) Catal. of Mar.
Poli/zoa, :37 ; Johnston, Bn'f. Zoopli.

CABINET for holding microscopic ob-
jects. See IxTRODiCTiON, p. xxiii.

C ACTA'CE.E.— Asiugular family of Di-
cotyledonous plants, especially remarkable,
microscopically, for the peculiar structure
of their wood-cells. See Spikal Fibrous
Structure, and Wood.

BiBL. Schleiden, Jnat. der Cadeen, 184 ;
Miquel, Ann. d. Sc. Nat. 2 ser. xix. 165.

CA'DIUM, Bail.— A genus of Rhizopoda,
fam. Aetinophryina ?. Animal unknown.

Cliar. Shell 'siliceous (?), ovoid, with a
bent beak, and a circular aperture ; often
with a long curved tapering appendage at
the base, and with numerous meridian lines,
of which about twelve are visible at once.

C. marinum (PI. 51. fig. 30). Soundings
in the sea of Kamtschatka, and the Gulf-
stream.

BiBL. Bailey, SilUmmis J. 1S56, xxii,
p. 3, pi. 1. f. 2 ; ' Wallich, M. M. J. i. p. 107,
pi. 3.

CAD 'MIIIM.— Solution of the oxide or
carbonate of this metal in sulphuric acid,
when evaporated on a slide, yields disks or
circular aggregations of minute radiating
needles (circular crystals) of the sulphate,
whicb exhibit essentially the same pheno-
mena under the action of polarized light as
those of the oxalurate of ammonia. The
disks frequently exhibit irregular undu-
lating, somewhat concentric dark bands,
indicating parts where no double refraction
takes place.

PI. 39. fig. 10 gives but a very imperfect
idea of the appearances presented by these
crystals when viewed by polarized light.

C.EOMA'CEI. See Uredinei and Us-

TILAGINEI.

CALA'NUS, Leach, = TEMORA.

CALCAPJ'NA, D'Orb.— One of the Ro-
taline Foramiuifera ; asymmetrically heli-
coid, with three or more whorls or cham-
bers ; coated with exogenous shell-growth,
as granules, spines, and stick-like processes.
Shell thick, with the vascular and supple-

mentary skeleton. Connnon in the Chalk
of Mae.-itricht, and in several Tertiary strata ;
and living abundantly in the Mediterranean
and other warm seas.

C. Spcngleri (I'l. 24. fig. 27).

BiBL. Reuss, Sitz. Ak. Wiss. Wicn, xliv.
315, 1861; Carpenter, Foram. 1862, 216,
&c.

CALCIUM, CHLORIDE OF. — This salt
may be prepared by adding excess of pre-
pared chalk to dilute muriatic acid, boiling
and filtermg the solution, and then evapo-
rating it to di'yness. The crystals belong
to the rhombohedric system, and are de-
liquescent.

An aqueous solution of chloride of cal-
cium is of great service in microscopic re-
searches, as objects which have been im-
mersed in or moistened with it do not be-
come dry at ordinary temperatures. Hence,
if a drop of the solution be added to an ob-
ject covered with thin glass, and excluded
from dust, it may be preserved without the
use of a cement to enclose it in a cell (see
Preservation). Its use in determining
the presence of cell-membranes has been
already alluded to (Introduction, p. xli,
§ 4). When employed for this purpose, its
action must always be controlled by the
action of water, crushing, &c.

The strength of the solution may be
about one part of salt to two of water, or a
saturated solution may be used ; it should
be kept in one of the test-bottles (Introd.
p. xxvii), with a lump of camphor floating
on its surface.

It frequently happens that the solution
in which objects have beeu immersed (on a
slide) exhibits crystals. These usually con-
sist of either the chloride itself, the sulphate
or the phosphate of lime, the two latter
formed from the alkaline salts derived from
the object.

CALCULI. See Concretions.

CALEP'TERYX, Linn.— A genus of
Neuropterous Insects, belonging to the fa-
mily LlBELLITLID^.

CALIA, W^erneck. — A doubtful genus
of Infusoria.

C/iar. Monads included in jelly (Pando-
rin(B) fixed to aquatic plants, not swimming
free. Two species. -

BiBL. Werneck, Ber. de Berl. Ak. 1841,
377.

C ALI'CKTM, Ach.— A genus of Lichena-
ceous Lichens, tribe Caliciei.

Char. Thallus granular, powdery, squa-
mulose or evansceut. Apothecia black, sti-

CALIGONUS.

[ 128 ]

CALOTHRIX.

pitate or subsessile ; spores brown or black.
Spermatia short, obloug.

Eighteen British species. C. hyperellum :
ou oak, lime, &c. Very common.

BiBL. Leig-hton, Lich.-Fl. 1879, 39 ; Tu-
lasne, Ann. d. Sc. N. 3 ser. xvii. 209.

CALIG'ONUS, Koch.— A genus of Aca-
rina, fam. Trombidina, Has the legs 7-join-
ted, and a line between cephalothorax and
abdomen.

C. nlQer. Not described by Koch, but
figured ; very minute.

BiBL. Koch, Uehers. ; Murray, Ec. Hat.
124.

CA'LIGUS, Miiller.— A genus of Crusta-
cea, of the order Siphonostoma, and family
Caliginea {Calk/ idee).

Char. Head in the form of a large buck-
ler, having anteriorly large frontal plates,
which are furnished with a small suctorial
disk or lunule on the under surface of each
lateral portion ; antennte small, fiat and
two-jiiinted. Thorax with only two distinct
articulations, thoracic segments uncovered ;
second pair of jaw-feet two-jointed and
not in the form of a suctorial disk. Legs,
four pairs with long plumose hairs, fourth
pair slender, of only one branch and serving
for walking.

Four species. Found upon the brill, cod,
mackerel, plaice, trout, &c. j length 1-5
to 1".

BiBL. Baird, BHt. Eatom. pp. 25(5, 2G9.

CALLIBT'NA, Ehr.— A genus of Kota-
toria, of the family Philodiu;ea.

Char. Eye-spots absent ; a proboscis and
a foot with horn-like processes.

The rotatory organ is double, but not
furnished with a stalk ; proboscis also cili-
ated ; foot elongate, forked, and with four
accessory horn-like processes, hence -sNith
six points altogether ; teeth small and nu-
merous (two only in each jaw in one species,
Gosse). Fresh water.

C. eleqans, Ehr. (PI. 43. fig. 10). Crys-
talline;'length 1-70". (PI. 43. fig. 11, jaws.)

C. rediviva, Ehr. Granular or fieshy, ova
red ; length 1-70".

C. hide/is, Gosse. Teeth two in each jaw ;
length 1-45".

C. constricta, Duj. Rotatory organ con-
stricted; length 1-50".

C. parasitica, Gig. On Gammarus and
Asellus.

BiBL. Ehreub. Inf. p. 482 ; Diijardin, Inf.
p. 055 ; Pritchard, Inf. p. 701 ; Gosse, Ann.
N. H. 1851, viii. p. 202; Giglioli, Qn. Mic.
J. 1863, p. 237.

Length ^4 o "• Fresh

CALLITHAM'NION, Lyugb.— A genus
of Ceramiaceas ( Florideous Algai) , containing
a large number of species, some common,
many rare. In the smaller species the struc-
ture is very simple, the branched feathery
fronds being composed of single rows of tu-
bular cells ; in the larger species the stem
and larger branches are strengthened by
external filaments, which grow over the
original axis, apparently originating at the
base of the upper branches and growing
down (somewhat as in Batrac7<u!'per7nani).
Antheridia have been observed in C. Barreri
and C. corymhosuni, collected in tufts on
the ultimate branches. The favdlce are
naked, and the tetraspores are tetrahedrally
arranged.

BiBL. Haryey, Mar. Alqts, pi. 23 A ;
Phyc. Br. pis. 129, 272, 2.30, kc; Thiiret,
Ann. d. Sc. K. 3 ser. xvi. p. 16, pi. 4; ]N'a-
geli, Ah/en-SiiAteme, 198, pi. 6.

CALLODIO'TYON, Carter.— A genus of
Rhizopoda (Flagellate Infusoria, Kent).

Char. Naked, free, ovate or variable,
highly vacuolar ; fiagella three, food admit-
ted by the surface

C. triciliatum.
water, Bombay.

BiBL. Carter, Ann. N. H. 1865 ; Kent,
Inf. 307.

"CALO'CERA.— A genus of Clavariei
(Hymenomycetous Fungi) difi'ering from
Clavaria in the subcartilaginous texture and
viscid hymenium ; the structure moreover
approaches that of Tremellini. C. viscosa,
which occurs on decayed pine-stumps, is one
of our most beautiful Fungi. Tln-ee or four
more species occur in this country.

BiBL. Berk. Oatl. p. 284.

CALODIS'CUS, Rabenhorst, = Crtwi^^yo-
discus.

CA'LOTIIRIX, Ag.— A genus of OscU-
latoriea) (Ct>nfervoid Algpe), growing in
tufts, the filaments forming a branched
frond by lying in apposition and being con-
creted by their sheaths here and there.
C. mirahilis, Ag. (PI. 8. fig. 22), is a rare
freshwater species in England, found on
mosses in small streams, ajrugiuous green,
growing blackish. Diameter of the fila-
ments about 1-1200 to 1-1800". Accord-
ing to Hassall, C. atroviridis, Harv., is not
distinct.

Other species.

Fig. 95 illustrates the close annulations on
the filaments of this genus ; the nature of
which will be treated more particularly
under the head of Oscillatoeiace.^.

CALYCELLA.

[ 129 ]

CAMBIUM,

m

BiBL. Hassall,^/£r«,243,pl.69.1; Fig. 95.

KiitziniT, Tab. Phi/c. cent. ii. pi. 29.
ii.; Dillwyn, Br. Confervm {C. })n-
rabilis), pi. 9lj ; Rabeiiliorst, Sp. Alg,
ii. 270 ; Boruct & Tliuret, Notes
Algol.

CALYCEL'LA, Ilincks.— A g-e-
nus of mariue Zoophytes, of the
order Hydroida, aud family La-
foeidfe.

Char. Stem creeping, simple; or
erect, compound aud branched ;
cells tubular, with an operculum
formed of convergent segments or
a plaited membrane ; polypes cy-
lindrical, "nith a conical proboscis.

C. syringa = Campanularia syr.
Very common on sea-weeds, &c, ^ , ^, .

^•, _r .- ■ , ' Calothnx

C. jastuiiata. Tomasi-

BiBL. Slmc\is,Brit.Zooph.-a.2Qo. niana.

CALYMPERACE.E.— A tribe j^agment
of Pottioid Mosses, containing one oTa
British genus : Ma™'ifled

Encalypta. Calyptra long, cylin- soodiauTs.
dricJilly bell-shaped, narrow above
on account of the clavellate operculum,
surpassing the capsule, firm, entire, torn or

Fi^. 96,

Fig. 98.

Fiff. 97.

Pig. 96. Encalypta vulgaris. Peristome.

Fig. 97. E. ciliata. Calyjitra.

Fig. 93. E. streijtocarpa. Fragment of peristome.

ciliated below (fig. 97). Peiistome absent,

simple (fig. 9G), or double (fig. 98). Ex-
ternal : sixteen lanceolate or long-subulate,
ciliil'orm teeth, mo.-;tly with a longitudinal
line, reddish, rugiUose. Internal : a delicate
membrane adherent to the tecith, produced
into cilia opposite or alternating with the

CALYPOGE'IA, Raddi.— A genus of
Jungermanniese (Hepaticse), founded on
Jungermannia Trichomanis, Dicks. The
leaves have a peculiar glaucous hue ; the
sporange is spirally twisted. Gemmge are
produced at the extremities of leafless pro-
longations of the stem.

BiBL. Hooker, Brit. Jungerman. pi. 79 ;
Etu). Botany, 1728.

OALYPTOS 'TOMA, Cambridge.— A ge-
nus of Acarina, fam. Trombidina.

C. Hardii. lieddish-yellow, punctate ;
eyes 6, in 3 pairs, forming a triangle.

Among moss ; Cheviot Hills.

BiBL. Cambridge, Ann. N. Hist. 1875,
xvi. 384 (fig.); Murray, Ec. Entojn. 140.

CAM'BIUM.— The name applied to the
young cellular layers from which the woody
structures of plants are developed. When
sections are made near the growing points of
any stems, as in terminal or axillary buds,
we find a quantity of extremely delicate,
slender, elongated cells, distinguished from
the generally rounded cells of the paren-
chyma, and forming rudimentary cords in
the situation of the future woody and vas-
cular bundles. In the Dicotyledons, they
stand in a circle, so as to separate the
pith from the young bark : the ring may
be seen in cross sections a little below the
growing-point. At the very apex of the
stem all the tissues merge into the delicate
universal generative tissue or meristem. In
the apex of Monocotyledonous stems, and
also those of Ferns and the higher Flower-
less plants, the cambium is found in delicate
cords imbedded in the nascent general pa-
renchyma, indicating, even in this early
condition, the position and arrangement of
the isolated fibrous and vascular bundles.
Sections of the outer region of the stem of
Dicotyledons demonstrate the existence of
a layer of cambium at the outer surface of
the youngest wood, which indeed passes
gradually into the cambium (figs. 792, 808).
This cambium is the tis.«ue from which the
succeeding layers of wood are generated ;
and its position on the outside of the fibro-
vascular bundles gives these their indefinite
power of development. The cambium of
the Monocotyledonous bundles becomes in-

CAMBRIC.

[ 130 ]

CAMPTOCERC'US.

closed between the wood and vessels of in-
dividual bundles, so that their growth is
limited. The cambium of the outside of
the wood of Dicotyledons forms new layers
of liber, in most cases, on the inside of the
old ones, pari passu with the development
of the layers of wood. Cambium, which
is in great part only an early and trans-
itional form of cellular tissue, afterwards
to become developed into wood, is com-
posed of delicate cellulose cells enclosing
a primordial utricle, nucleus, and abun-
dance of nitrogenous protoplasm, but usually
without chlorophyll. The cells multiply
bj^ transverse division in the elongation of
the stem, and by perpendicular division
("tangential and radial) as the stem expands
in diameter. This process is effected by
the constriction of the primordial utricle
and gradual development of a septum, as
in ordinary vegetative cell-development.
The cambium of most Dicotyledons is gra-
dually matured into wood from within
outwards ; but in the Monocotyledons and
Flowerless Cormophytes it often remains in
great part in a delicate and soft condition,
forming the vasa propria of Mohl. Owing
to the delicacy of its structure, cambium
was formerly imagined to be a thick muci-
laginous fluid poured out in the growing re-
gions of plants (as between the wood and
liber of Dicotyledonous stems in spring) ;
which by degrees becomes organized and
converted into cellular tissue, by the inde-
pendent origin and subsequent coalescence
of a number of cells generated in this fluid.
This erroneous view was strongly supported
by Mirbel and others.

BiBL. Treviranus, PJiys. d. Gewdchse, i.
159; Mirbel, Ami. d. Sc. X. 2 ser. xi. .321,
xix.197; 'Piiyen,Co7npt.Eend.lSS9; Schlei-
den, Botanik ; Henfrey-Masters, Botany ;
Nfigeli, Zcitsch. f. n-iss. Bot. iii. 6-1, & Mikr.
576; ^ioh\,Ve(jetah. Zelle (l^Ywasl.)] Schacht,
Pfanzenzelle ; ' Sachs, Bot. 8.3.

CAMBRIC. — This name was formerly ap-

?lied strictly to the finest kind of linen cloth,
t is used now in a loose sense in trade.
French cambric, however, ought to be linen.
Scotch and English cambrics are commonly
made of cotton, while Indian cambric is
made of the grass-cloth flbre. The fibres
may be distinguished under the microscope,
and the value of the fabric thus ascertained.
See FiBROtTS Substances and Cotton.

CAMERA LUCIDA. Introduction,
p. xxii.

CAMPANULA'RIA, Lamk.— A genus

of Hydroid Zoophytes; family Campanu-
lariidse.

Distinguished by the creeping or erect
polypidom, the filiform continuous main
tube, giving oft' its stalked and campanulate
cells irregularly or in whorls, the usually
long, ringed stalks, and the scattered, ses-
sile vesicles.

Hincks defines the genus thus : — Stems
simple or branched; cells bell-shaped and
hyaline, without operculum; polypes with a
large cup-shaped proboscis; germ-cells borne
on the stems or the creeping stolon, with
fixed spore-sacs. 13 species; 3 doubtful.

C. voluhilis (PI. 41. fig. 4). Stem a
single tube, creeping, filiform ; cells on long,
slender ringed stalks, campanulate, with a
serrated margin ; vesicles ovate, wrinkled
concentrically. Parasitic on sea-weeds &c. ;
frequent. It forms an elegant microscopic
object.

C. dumosa. Stem compound, erect or
climbing, irregularly branched; cells long,
tubular, patent, almost sessile, orifice entii-e.
In deep water.

BiBL. Johnston, Brit. Zooph. 107; Gosse,
Mar. Zool. i. 24 ; Hincks, Brit. Zoopli.
160.

CAMPANULAR'IID^E, Johnston.— A
family of marine Hydroid Zoophytes.

Char. Those of Sertulariidte, but cells
stalked.

Genera : Campamdaria, Laomedia.

Hincks revises the family thus: Cells
terminal, stalked, campanulate ; polypes
with a large trumpet-shaped proboscis.
And admits the genera Clytia, Ohelia, Cam-
pannlaria^ Lovenella, Thaumantias, and Go-
nothi/rcea.

BiBL. Johnston, Brit. Zooph. ; Gosse,
Mar. Zool. i. ; Hincks, Br. Zooph. p. 137.

CAMPANUBI'NA, Van Benedon.— A
genus of marine Hydroid Zoophytes; family
Campauulinida3.

Char. Stem simple or branched, rooted ;
cells pointed above ; polypes cylindrical,
with webbed tentacles ; reproduction by
free medusa-buds, single in each capsule.
3 species.

BiBL. Hincks, Brit. Zoopih. p. 186.

CAMPANULPNID^E. — A family of
Polypi, order Ilydroida.

Char. Cells ovato-conic, stalked; polypes
long, C3dindrical, with a small conical pro-
boscis.

G eneva : CampanuUna, Zygodactyla, Oper-
cularclla:

CAMPTOCER'CUS, Baird {Lynceus

CAMPTOSURUS.

[ 131 ]

CANDONA.

Miill. pt.). A genus of Entomostraca, order
Cladocera, fiimily Lynceid;^.

Char. Carapace ovoid ; beak blunt, di-
rected forwards or slightly downwards ; ab-
domen long, slender, tail-like, extremely
flexible, and serrated. 1 species :

C. macroiirufi (PI. 20. fig. 4). Carapace
striated longitudinally, slightly sinuated and
ciliated on the anterior margin ; beak rather
blunt; aquatic.

BiBL. Baird, Brit. Enfom. p. 128.

CAMPTOSU'RUS, Presl, = Seolopen-
drimn, pt.

CA3IPT0THE'CIUM,Br. Sciich. = Hyp-
nuin in part.

CAMPTOUM, Link.— A genus of De-
matiei (Hj^phomycetous Fungi), allied to
Arthrininm. C. ci/rvatum, Lk. (Arthrinium
curvitfum, Kze.) grows in tufts of very slen-
der filaments, bearing very minute, curved
spores, upon Scirjnis si/!vuficus.

BiBL. Berk, and Br. Ann. JV. H. 2 ser.
viii. 100; Fries, Sijst. Myc. iii. 377 ; Corda,
Ic. Funq. iii. pi. 1. fis'. 17.

CAMPY LODIS'CUS, Ehr.— A genus of
Diatomacefe.

Char. Frustules single, free, disk-shaped ;
disk curved or twisted (saddle-shaped) ; fur-
nished with mostly radiate markings, which
are frequently interrupted. Aquatic and
marine.

The markings are costae or canalicidi,
forming minute canals between the internal
cell-membrane and the surrounding fluid
(Smith).

Smith describes 9 species (British) ; Ra-
benhorst describes 28 European species, and
enumerates 27 foreign and fossil species.

C. costatus, Smith (PL 16. fig. 16). Valves
circular ; radii 30-40, extending about half-
way to the centre, which is minutely
punctate ; diameter 1-270" ; aquatic.

C. spiralis, Smith. Outline of front view
resembhng a figure of 8; valves elliptical;
radii about 00, nearly parallel and trans-
verse; length 1-160" ; aquatic.

C. clypeus, Ehr. (PI. 2o. fig. 18). Valves
suborbicidar, exhibiting a circular and a me-
dian transverse hyaline line ; radii broad,
interrupted in the middle, which is punctate ;
length 1-200" ; aquatic and fossil.

BiBL. Smith, Br. Diat. ; Kiitzing, BaciU.
and Sp. Aly. ; Rabenhorst, Fl. Alg. i. 4o ;
Grun, Wien. Verh. 1862 j Schmidt, Atlas
Diatom.

CAMPYLOXE'IS, Grun.— A genus of
Diatomacese, family Entopylcaj.

Char. Frustules scutelliform, adnate.

transversely arcuate ; valves heterogeneous
— the inferior costate, the superior cribroso-
punctate ; nodules absent.

C. Argus. Atlantic.

BiBL. Grun, Wien. Verhayidl. 1802, 429.

CAM'PYLUPUS, Brid. (Musci) = Di-

CRANUM.

BiBL. Wilson, Brytil. Brit. p. 87.

CAM'PYL0PUS,C1. and Lachm.— A ge-
nus of marine Infusoria, family Oxytrichina.
C. paradoxus (PI. 51. fig. 29). With six
posterior setae, and eight posterior feet, six
on the right and two on the left side. Re-
markable for its bounding leaps, which
make it very difficult of observation.

BiBL. Claparede and Lachmann, Lifus,
p. 184.

CAMPYLOSTE'LIUM, Br. and Sch.—
A genus of Leptotrichaceous Mosses, inclu-
ding some Dicrana and Grimmice of older
authors.

BiBL. Wilson, Bryol. Brit. p. 51.

CAMPYLOS'TYLUS, Shadb.— A genus
of Diatomaceae : = Sijnedra, sp.

BiBL. Greville, Qu. Mic. J. 1862, 232.

CANADA BALSAM. See Balsam.

CANALICULL See Bone.

CANCER. See Tumoues.

CANCROID. See Tujioues, Cancroid.

CANDA, Lamx. (CeZ/M/a/va part, John-
ston).— A genus of lufundibulate Polyzoa
(Bryozoa), of the suborder Cyclostomata,
and family Cellulariidse.

Distinguished by the jointed, branched,
erect polypidom, the flat, linear branches
with the cells on one plane, and the cells
having a vibraculum in a notch on the outer
side but no avicularium at the upper angle.

Placed with Scrupocellaria by Hincks.

C. rt'pfans (Cellularia rept., Johnston)
(PI. 41. figs. 5, 5 c, and 5 d). Orifice oval,
with 3 or 4 marginal spines, and a stalked
operculum with a lobed lamina. Common.

BiBL. Johnston, Brit. Zooph ; Busk (Brit.
Mm.) Polyzoa, 26 ; Hincks, Polyzoa, 43.

CANDA'CE, Dana.— A genus of Ento-
mostraca (Copepoda).

G. pectinata. Dredged at Scilly.

BiBL. Bradv, Copepoda (Ray Soc), 1. 48.

CANDEI'NA, D'Orb.— A "modification
of the Globigerine type of Foraminifera
(according to Brady); built up with a
three-sided alternation, and having a row of
pseudopodial pores along the base of its last
chamber.

BiBL. D'Orbignv, For. Foss. Vien. 193 ;
Bradv, Qu. Mic. Jn. 1879, xix. 78.

C ANDO 'N A, Baird( Cypris in part, MUll.) .

k2

CANNA.

[ 132 ]

CAPILLARIES.

-^A genus of Ostracoda (Entomostraca),
family Cvpridse.

Char. Two pairs of antennae ; superior
long, with numerous joints and a pencil of
long filaments ; inferior stout and pediform,
without a tiift of long hairs or filameuts (see
Cypeis) : eye single ; motion creeping only.
Five British species ; freshw.

C. albicans, Br. ; lactea,Bd.; compressa,
Koch ; Candida, INIiill.

BiBL. Baird, Entom. 159 ; Norman, Ann.
N. II. 1862, ix. 46; Brady, Linn. Tr. 1868,
xxyi. 381.

CANNA. — A genus of Monocotyledonous
plants belonging to the same natural family
as the arrow-root (Marantacese), and valu-
able from the same cause. Tous-les-mois is
a starch derived from the tubers of a Canna,
supposed to be C. edulis, Ker. The grains
of genuine Tous-Ies-muis have distinctive
microscopic characters, as shown in PL 46.
fig. 25.

CANTHAREL'LUS.— A genus of Aga-
ricini (Hymenomycetous Fungi), differing
from Aqaricusm the vein-like gills.

CAN'THOCAMPTUS, Baird {Cydops,
pt., Miill.).— A genus of Entomostraca, of
the order Copepoda, and family Cyclojndae.

Cha7\ Jaw-feet small, simple; inferior
antennae simple ; ovary single.

Four species : one aquatic, three marine.

C. minutus (PL 20. fig. 6). Thorax and
abdomen not distinctly separate, coiisisting
of ten segments, successively diminishing
in size, the last terminating in two short
lobes, from which issue two long filaments,
slightly serrate on their edges; antennae
short, seven-jointed in the male, nine in
the female ; inferior antennae simple, two-
jointed, the first joint with a small lateral
■joint, terminated by four setae ; feet five
pairs.

Common in ditches ; colour reddish,
length about 1-15". (PL 20. fig._ 6 : a, in-
ferior antenna; b, first pair of jaw-feet;
c, second pair.)

C. crypt Oram, Brady. In a coal-mine.

BiBL. Baird, Brit. Entom.; Brady, Qu.
M. Jn. 1860, p. 23.

CAOUTCHOUC— A gum-resinous sub-
stance contained in the milky juices of many
plants, but most abundantly in those of the
families Euphorbiacere, Urticace.'u and Apo-
eynacea3, whence the India-rubber of com-
mence is obtained. The caoutchouc appears
in the form of minute globules suspended in
a watery fiuid containing a gummy sub-
stance; SO that the milky juice may be

regarded as a kind of emulsion. See
Latex.

CAPILLARIES.— The minute interme-
diate vessels which the blood traverses in
passing from the arteries to the veins.

The capillaries appear to consist of a deli-
cate, transparent, tolerably resisting and
elastic membrane, and a number of oval or
rounded longitudinal nuclei ; but when
treated with very dilute solution of nitrate
of silver, the dark dyed outlines of the epi-
thelial cells, to which the nuclei belong, are
brought to light (PL 51. fig. 31). The dia-
meter of the human capiUaries varies from
1-5000 to 1-1000", the most common being
perhaps 1-3000". The size of the capillaries
in the Vertebrata generally, bears a relation
to the size of the coloured corpuscles of the

Fig. 99.

Magnified 300 diameters.

One of the smallest vessels from the arterial side. 1,
smallest artery ; '2, transition ve-isel ; 3, large capillaries ;
4, small capillary, a, structureless membrane \yith few
nuclei, representing the adventitious coit; 6, nuclei of
the muscular flbre-cells; c, nucleus inside the small
artery; d. nuclei of the capillaries and intermediate
vessel. From the human brain.

blood ; and thus they are largest in Birds,
Fishes, and Reptiles. The larger capillaries

CAPNODIUM.

[ 133 ]

CARBASEA,

have thicker -v^-alls aud more numerous cells
than the smaller ones.

The capillaries branch and anastomose
freely, giving- rise to the beautiful networks
60 well known as favourite microscopic
objects when injected.

The most important pathological changes
which the capillaries undergo are those of
the Fatty and amyloid Degeneratiox,
The general arrangement of the capillaries
is best seen in injected preparations (Injec-
tion). Their structure may be examined in
pieces of the pia mater, of the retina, or the
mesentery of an animal : a minute portion
of washed lung will also answer the purpose
well. Tliese should be dissected with the
mounted needles. The relation of the ca-
pillaries to the surrounding minute struc-
tures may be shown in portions of tissue
which have been imperfectly injected, or
injected with a liquid containing a small
quantity only of opaque colouring-matter ;
in these the capillaries may be recognized
by their containing the scattered granules
of the colouring-matter. Between the cells
are certain spaces (stomata), best seen in
silvered preparations. In the spleen-pulp,
and in the tissues of many of the lower
animals, the finest currents of blood pass
through lacunae or wall-less channels.

The capillaries are developed from
"branched connective corpuscles. Non-
medullated nerves have been traced into
the walls of the capillaries.

Acetic acid is frequently of use in rendering
the tissues transparent, and bringing the
nuclei to light. The finer capillaries are
made more distinct by dyeing with carmine
or logwood.

BiBL. KoUiker, 31{kr. An. Bd. ii. ; Henle,
Allg. Anat. ; Frey, Histohgk (full Biblio-
graphy) ; Schmidt, Mn. Mic. Jn. xJii.
1 (tigs.) ; Eberth, Stricker-^s Hanclhxch ;
Chrzonszczewsky, Virchoid's Arckiv, xxxv.
169; Cornil SciianyieT, Hist, path.; Rind-
fleisch, Ht'st. ; and the Bibl. of Tissues.

CAPNODIUM, Montagne.— A genus of
Perisporiacei (Ascomycetous Fungi) grow-
ing as a kind of mildew on leaves and shoots,
forming a blackish flocculent coat composed
of short, branched, beaded or moniliform
filaments, densely interwoven. The peri-
thecia arise vertically from this, and are
either simple or branched, at first simple
sacs, but probably aftei'v\-ards thickened by a
layer of cells ; a nmnber of threads ultimately
grow lip from the mycelium, partiallycover
the central sac ; and, closely crowded, some

of their tips project beyond it, forming a
fringe; the cells of this fringe readily become
detached and appear to reproduce as conidia.
The central sac contains largish delicate asci,
probably often absorbi^d at an early period,
so as to set the spores free in the cavity.

Particular joints of the filaments some-
times become 7«/c»/(-/m, producing free spores
in their interior, without asci.

Several species seem to occur in Britain ;
and amongst them C. elonc/atum, Berk. &
Desm. On pear-leaves.

C. (^Fumago) quercinum, Pers., grows on
oak-leaves.

C. (Fumago) Footii, Berk. & Desm., on
evergreens, on the birch-tree, and on Mer-
cwialis 2}ere7iiiis.

BiBL. Berkeley, Cn/pt. Bot. p. 275 ; Berk.
& Broome, Ann. N. H. 2ud ser. xiii. p. 408 ;
Berk. & Desmazieres, J. Hort. Soc. iv. 2-t3 ;
Montagne, A/in. JV. H. 2nd ser. iii. p. 520.

CAPSOSI'RA, K.— A genus of Rivu-
lariefe.

Char. Filaments erect, narrow, crowded,
parallel, moniliform, sheathed ; cells thick-
walled.

C. Brebissonii (PI. 63. fig. 11.). Greenish
black. On stones, in streams (France).

BiBL. Kiitzing, Sp. Alg. 344 ; Raben-
horst, Fl. Alg. ii. 223.

CARAPACE, or Lorica. — A term some-
what indefinitely applied to the whole or a
part of the shell or outer coat of certain
animals — as those belonging to the classes
Crustacea, Rotatoria, Infusoria, Sec.

In regard to the Rotatoria and Infusoria, it
has been divided into : — the testa or testula,
an envelope resembling that of the tortoise,
within which the body of the animal is en-
closed, the head and the tail being free — as
in the genera Brachionus, Monura, Colurus,
&c. ; the sciitelhnn, a round or oval envelope,
covering only the back of the animal, in the
manner of a buckler; and the urceolus, a
membranous or firm envelope, sometimes
gelatinous, in the form of a bell or cylinder,
open at one end and closed at the other, and
within which the animal can completely
retract itself — as in Dipflugia &c.

Ehrenberg extended the use of this term
also to the external envelope of Volvox,
Gonium, and the Dia'tomacese. As these
have been removed to thevegetablekingdom,
it is not now applied to them.

_ CARBA'SEA, Gray.— A genus of Infun-
dibulate Polyzoa, of the suborder Cheilo-
stomata, and family Flustridae (Flustra, pt.,
Hincks).

CARBOLIC ACID.

134 ]

CARrOMITRA.

Distinguislied by the expanded, leafy,
flexible, erect polypidoms ; and the cells
being arranged in many rows, on one side
only.

C. impyrea (Flustra carhasea, Johnst.)
(PI. 41. tigs. 19, 20). Cells oblong, narrowed
and truncate beloAv, convex, unarmed. Deep
waters.

EiEL. Johnston, 7?/-. Zooph. 345 ; Busk,
3Iar. Poh/zoa, 50 ; Ilincks, Pohjz. 123.

CARBOLIC ACID or Phenole.— This
substance is largely used as a germicide and
antiseptic, and is very valuable m the pre-
servation of animal and vegetable structures.
The pure crj'stallized acid should be j>ro-
cured. See Pbeservation.

CARBONATE OF LIME. See Lime,
Carbonate of.

CARBO'NIA, Jones. — A genus of small
Cypridiform JEntomostraca, found in the
Carboniferous strata, and distinguished
chiefly by their peculiar muscle-spot.

BiDL. "T. R. Jones, Geol. May. iii. 218,
pi. 9, f. 4-10 5 Jones & Kirby, Ann. N. II.
1879, iv. 28.

CARBONIC ACID.— The presence of
this gaseous acid is usually determined by
the addition of another acid, as acetic or
muriatic, to the object under the microscope;
and if colourless and inodorous bubbles
escape, it is concluded, and in most cases
correctly, that carbonic acid is present.

It must be borne in mind that if the object
be immersed in liqiiid, the gas may arise
either from this or the object; for it i.s well
known that the escape of a gas from a Hquid
charged with it is greatly facilitated by the
presence of a solid and especially a pointed
body, and that the gas escapes from the
liquid at its surface or point ; thus the
false appearance is produced of the gas being
liberated from the body. Hence the import-
ance of washing the object before the addition
of the acid.

When crj'stalline bodies of different forms
are present, these must be separated before
the addition of the acid; otherwise the bubbles
liberated from tliose of one kind, by escaping
at the surface of the others, may give rise to
the false conclusion that they were derived
from the latter.

Recollection of the fact that carbonic acid
is readily absorbed by solution of potash,
would allow of the distinction of bubbles
of this acid from those of air.

CARCHE'SIUM, Ehr.— A genus of
Infusoria, belonging to the family Yorti-
cellina.

Char. Pedicle branched, spirfilly flexible ;
bodies of the animals all alike ( = branched
Vorticellce).

C.pohipinum (PI. 30. figs. 20, 21). Cam-
panulate, expanded in front; cuticle smooth;
nucleus recurved in a longitudinal plane ;
pedimcle not jointed; length of bodies
1-580-1-430"; freshw.

C. spectahilc. Thimble-shaped, not ex-
panded ; cuticle finely striated ; nucleus re-
curved in a longitudinal plane, with several
sinuosities; peduncle not jointed ; freshw.,
foetid.

C. EpistijUs. Body very narrow, smooth ;
nucleus curved in a transverse plane ; pe-
duncle distinctly jointed; freshw., in iusect-
larvce.

BiBL. Ehrenb. Inf. and Bei: d. Bed. Ah.
1840, 199 ; Dujardin, Inf. 551; Stein, Infus.
48, &c. ; Clap, and Lachm. /?;/. 97; Kent,
Infusoria, 690.

CA'RIS, Latreille. — A doubtful genus of
Acarina.

C. vespertilionts is found upon the bat
( Vespertilio i)ipii^treJh(s)j supposed to be the
larva oH Deriiunii/ssus, or Arc/as.

BiEL. LatreUle, Gen. Crustac. ^-c. i. IGl ;
Audouin, Ann. d. Sc. N. Zool. xxv. 412 ;
Walckenaer, Ajrieres (Gervais), 227.

CARMINE.— This beautiful pigment is
sometimes used to feed Infusoria and fill
their sacculi or gastric spaces (Infusoeia).

It is also used as a colouring-matter for
injections and. for dyeing or stainiag tissues
(see Staining).

CAR'PAIS. See Gamasus.

CARPENTE'RIA, Gray.— A genus of
Foraminifera allied to Globif/rrina, but
ceasing at an early age to grow spirally, and
then forming expanded tent-like chambers
which enclose the first-formed cells ; at-
tached by the base to shells or corals, and
with a crater-like common aperture at the
apex. Siliceous spicules occur in the cells.

C. halanifurmis. (PI. 51. fig. 28.)

BiBL. Carpenter, Introd. Furam. 186.

CARPOGLY'PHUS, Robin, = ^ca?-Ms
sp. (p. 5). ^

CAR'POGON,the name applied by Sachs
to the fruit or sporocarp of his Class Car-
posporefe. See Vegetable Kixgdoji.

GARPOMI'TRA, Klitz.— A genus of
Sporochnacea3 (Fucoid Algfe) containing
one rare British species, C. Cahrerce, Clem.,
remarkable for the peculiar mitre-shaped
conceptacle containing the spores.

BiBL. Harvey, Marine Alg. pi. 5 B,
Phyc. Brit. pi. 14.

CARTILAGE.

[ 135 ]

CARTILAGE.

CARTILAGE.— Cartilage consists of a
firm, but elastic, l)lui.sh, milky or Yellowish
substance, which morphologically forms
either a simple parenchyma composed of
celb, or a structure consisting of cells
immersed in an intermediate basis.

The cells of cartilage are usually round,
oval, elongated or angular, frequently Hat-
tened and sometimes spindle-shaped. In
some cartilage they appear stellate, or ex-
hibit distinct radiating processes, as in
that of the cuttle-fish, the sharks and rays,
and enchondromatous gi'owths.

In the ossifying pseudo-cartilage of true
bone, real stellate cells are however met
■with. See BoxE.

Fig. 100.

Magnified 350 diameterB.

Primary (parent-) cells with one and two nuclei, or
two and four secondary cells and intervening basis.
From the cranial cartilage of a full-grown tadpole.

The cell-Avalls are generally thick, and
frequently composed of several layers or
capsules. " The contents consist of a clear
liquid and a nucleus ; sometimes the cell
and sometimes both the cell and the
nucleus contain one or more globules of
oil. The cells also frequently constitute
parent-cells, i. e. cells containing other or
secondary cell? within them, these con-
taining also nuclei or tertiaiy cells.

The secondarv' and tertiary cells some-
times exhibit well the internal layers.

It is undecided whether these capsular
layers are hardened products of secretion of
the cells, or whether they represent the
changed peripheral portions of the cell-
bodies themselves. The latter seems most
probable.

The intervening basis is either homoge-
neous, finely granular, or fibrous; sometimes
the fibres are distinct and can be isolated.

The simplest form of cartilage, viz. that
composed of cells only, is met with in the
chordd dorsalis or notochord of embryos, in
the adult skeleton of many fishes, the ten-
tacles of the Acalephaj, and in the cartilage
of the ear of many mammals. The proto-
plasm in these cells often exhibits radiating
strife in which currents are visible. The
structure is beautifully seen in the chorda
dorsalis of a young tadpole or Triton, or in
the ear of the moase (PI. 49. fig. 38). In

Fig. 101.

../

Magnified 3.50 diameters.
Cells from the gelatinous nucleus of the interverte-
bral ligaments. 1 a, large primary cell with a septum
formed by two secondary cells, and five tertiary cap-
sular cells or cells of the second generation with concen-
tric walls and shrunk nuclei c in the small cell-cavities.
2, primary cell a, with two secondary cells separated
by a delicate septum b, with thickened walls, a small
cavity and a shrunk nucleus e.

the latter instance, each cell is filled with
a globule of oil, which must be separated by
digestion in ether before the cell-structure
can be jjroperly examined ; but boiling on a
slide in solution of potash, or the addition
of sulphuric acid will liberate the globules
of fat from parts of a section. This variety
ofcartilage exactly resembles in appearance
a section of vegetable cellular tissue.

The second variety of cartilage, in which
the basis is more abundant and homo-
geneous or finely granular, true or hyaline
cartilage as it is called (PI. 49. fig. 39), is
met with in the larger cartilages of the
respiratorv' oigans, in the articular, costal,
ensifurra and nasal cartilages. In this the
cell-walls are closely adherent to the inter-
cellular ba.sis, so that they are rarely visible
without the use of reagents. The cells are
most numerous in the articular cartilages,
and arre mostly smaller the further they are
from the bone. Their long axes are placed
perpendicularly to the axis of the bone,
except in a thin layer next the surface of
the joints, in which they are parallel to the
surface. Both the cells and the nucleus of
this cartilage exhibit a fibrous network.

CASEINE.

[ 136 ]

CATHAEIXEA,

The third variety of cartilage forms fibro-
or reticular cartilage (PI. 49. fig. 40). In
this, the fibres consist either of white
fibrous tissue, forming white fibro-cartilage,
as in the intervertebral and interarticular
cartilages ; or of elastic tissue, forming
yellow or elastic fibro-cartilage, as in the
epiglottis, the ear. and the Eustachian tube.
It consists principally of fibres, single or in
bundles, sometimes running parallel, at
others interlacing; and between them lie
the cartilage corpuscles. Sometimes the
basis of hyaline cartilage becomes fibrous,
and true fibres may be found in it.

Bubnoff describes, in cartilage treated
with osmic acid, a complex network of
canals, passing in all directions through the
cartilage.

In regard to chemical composition, the
homogeneous basis usually consists of chon-
driue. The cell-walls are composed of a
substance allied to elastic tissue ; they are
not dissolved by boiling in water, and are
acted upon with difficulty by acids and
alkalies. The liquid within the cells is
probably albuminous ; it is coagulated by
water and dilute organic acids, and is readily
soluble in alkalies.

When sections of cartilage are subjected
to the action of Schultze's test, the cells
are coloured red, but not the basis.

By macerating hyaline cartilage in dilute
acids or warm water, the matrix often
exhibits concentric lamina?.

Some staining agents are useful in
enabling the components of hyaline cartilage
to be distinguished. Thus, the fat-globules
are blackened by osmic acid ; chloride of
gold colours the cells violet ; and nitrate
of silver stains the matrix (Rutherford).

BiBL. Kolliker, Mik. An. Bd. i. ; Henle,
Alh/. Atnit. ; Redfern, J^d. Month. Journ.
1851-1854 ; Mulder (and Bonders), Vhys.
Chemie ; Frey, Histol. 184 ; BubnofF, Ber.
d. Wien. Ak. Ivii. ; Klein, Hist., 48 ; Ge-
genbam-, Vergl. An. 27; RoUett, Strieker^ s
GetceM. ; and the Bibl. of Tissues.

CASEINE is the proteine constituent of
milk. It possesses no microscopic charac-
ters.

Some years since, a tumbler containing
porter, at the bottom of whicli was a small
quantity of a whitish sediment, was brought
to us for examination, suspicion being enter-
tained that the white deposit consisted of
some poisonous substance which had been
added by a woman ■R'ith the view of poisoning
her husband, the two not being on good

terms. The deposit examined microscopi-
cally and microchemically was found to
consist of an amorphous substance, giving
the chemical reactions of a proteine com-
pound, with entangled globules of oil. This
rendered it probable that it consisted of the
caseine of milk, with globules of butter.
It was afterwards recollected that milk had
been put into a tumbler kept in the place
from which this had been taken ; and thus
the toatter ended.

CASSAVA.— The coarser part of the
starch (tapioca being the finer) derived from
the tuberous root of the Jatropha Mnnihot,
L. (Janij)ha Manihot, Knth. ; Mcmihot vti-
lissima, Pohl), a Brazilian plant of the
family Euphorbiaceos. The starch-grains
are represented in PI. 46. fig. 14.

CASSEBEE'RA, Kaulf.— A genus of
Pteridefe (Polypodiaceous Ferns), nearly re-
lated to Adiantum. 3 species : Brazil.

Bibl, Hooker, Siin. Fil. 142.

CASSIUULI'NA, D'Orb.— A group of
JPo?-amm2yf?'« subordinate to Bidimina. The
chambers are alternate in unequal pairs, and
form a more or less discoidal, instead of
spiral, coil. The aperture is oblique, formed
by an inverted slit-like fold of the lower
part of the septal face, as in Bulimina.

Two British recent species, C. Icevigcda
(PI. 23. fig. 45) and crassa, are common ; and
a few others, with these, are found in all
seas, and in the middle and later Tertiaries.

Bibl. "Williamson, Foram. 68, figs.
140-144; Carpenter, i^or^TO. 197; Parker
and Jones, PW. Tr. civ. 377.

CATASCOTIUM, Brid.— A genus of
BartramioidefE (Acrocarpous Mosses).

Bibl. Wilson, i?^7/o/. iV/;!. p. 285; Berke- ,
ley, Brit. Mus. p. 168.

'CATENEL'LA ,Grev.— Agenus of Cryp-
tonemiacese (Florideous Algas), represented
by one British species, C. Opitntia (PL 4.
fig. 21), which is not uncommon on marine
rocks near highwater mark. It presents a
mass of creeping fibres, from which arise
densely matted fronds 1-2 to 1" high.
Colour dull dark purple. The favci/idia are
contained in the lateral capsular bodies
(fig. 102) ; the tetraspores are imbedded in
the peripherv of the loosely cellular axis
(fig. 103).

Bibl. Greville, ^/r/. ^r^V. pi. 17; Harvev,
Br. Mar. Ak/. pi. 20'B ; Ph/c. Brit. pi. 88 ;
Ent/1. Bot. {Bivularia Opuntia), p], 1868.

CATERPILLARS. See Insects.

CATIIARrXEA, Ehrh.— A genus of
Polytrichaceous Mosses, containing some of

CATTLE-PLAGUE.

[ 137 ]

CELL.

Fig. 102.

Fig. 103.

CateneUa Opnntia.

Fig. 102. Fragment of a frond, with lateral capsular
bodies containing the favelMia. Magnilled 10 dia-
meters.

Fig. 103. Transverse section of the axis, showing the
immersed tetraspores. JVIagniiled 50 diameters.

the Pohjtricha of autliors, having a naked
calyptra ; ^Atrichum aud Oligotrichum oi
Wilson's Bryoloqia.

BiBL. ^Yllson, Bryol. Brit. pp. 202, 204.
CATTLE-PLAGUE or Rinderpest.—
This terrible disease requires a brief notice
on account of its microscopic relations.
Careful examination of the muscles of ani-
mals ^^•hich had died of it showed the pre-
sence of "Entuzoa." The.se were found
afterwards to be Psorospermice, and to exist
in healthy as well as in di.<eased animals ; so
that they had no connexion with the malady.
A most copious Bibliography of the para-
sites infesting cattle is given in Cobbold's
■work, p. 3o2.

BiBL. Beale, Q>i. 3Iic. Jn. 18G6, p. 141
(figs.) : Cobbold, Parasifes, 1879, p. 280.

CAYENNE PEPPER.— This substance
consists of the ground seed-vessels of various
species of Capsicum ; it is often adulterated
botb with substances increasing the bulk,
and with mineral colouring-matters. For
the detection of the former the microscope
is employed, first studying the characters
observed in the true unground peppers.
Turmeric and rice-flour are named as falsify-
ing substances ; red earths, vermilion, and
red lead are detected by chemical analysis.

BiBL. That of Adulterations.

CECIDOMYTA, Latr.— A genus of Dip-
tera, of the family Tipulidfe.

C. tritici is the wheat-midge, which de-
posits its eggs in the flowers of com. Tiie

yellow larvpe wound the ovai'y, and so cause
a form of blight.

C. destructor, the American wheat-midge,
or Hessian fly, is still more injurious to
crops.

These insects may be found among the
ears of corn in the evening during the month
of May or June.

BiBL. \sAxh\,Linn. Tr.m..,i\.,x.\ West-
wood, Intr. p. ol9 ; Sidney, BliyMs of the
Wheat, p. 109.

CE'CROPS, Leach.— A genus of Crusta-
cea, of the order Siphonostoma, and family
Caligina.

C. LatreilUi. Found on the sun-fish
(^Orthaqoriscus viout). Female, length 1",
male 1-3".

BiBL. Baird, Brit. Entomosf. p. 289; V,
d. Hoeven. Handb. d. Zoologie, i.

CEDAR. — The Cedar of Lel)anon is the
Abies or Pinus Cedrus. The fragrant so-
called ' cedar,' of which pencils &c. are
made, is the wood of Juniperus virginiana.
See CoNiFERJE and Wood.
CELL, Animal. — The tissues and organs
of animals, like those of plants, are in great
part made up of or derived from cells ; but
the full-grown structures of animals are
strikingly distingui-shed in general from
those of vegetables by the departure from
or disguisal of the primitive ceUidar consti-
tution.

Under tbe head of Cell, vegetable,
the cell is defined as a vesicle or sac con-
sisting of a membrane composed of cellu-
lose, containing within it a nitrogenous
structure, the vital part, called the proto-
plasm or primordial utricle. In animals, as
in the earlier stages of many plants, this
protoplasm may exist alone, either forming
the entire organism, or its parts only, with-
out a membranous envelope forming the
true cell or closed sac, as in Amceba and
analogous organisms; but ordinarily the
animal cell, like the vegetable, is a true shut
sac, enclosing liquid or gelatinous protoplas-
mic contents, the membrane, however, being
Here almost always composed of a nitroge-
nous compound, and only in a few cases of
celhdose or allied substances such as pre-
vail in the solid parts of plants.

The membrane of-animal cells is ordinarily
transparent and colourless, mostly smooth,
and so thin as to exhibit only a single
boundary line ; more rarely the membrane
is tolerably firm, presenting a measurable
thickness, — while it is sometimes very thick,
and appears to consist of several layers.

CELL.

[ 138 ]

CELL,

Occasionally the membrane lias a granular
appearance, arising from projections de-

Kendent on granules lying on the inside.
To structure can be detected in the cell-
membrane itself.

The membranous cell generally contains
a liquid or semifluid protoplasm, the consis-
tence of which varies ; in this float, or are
suspended, molecules, granules, globules, or
other very minute cells. But modern ob-
servations indicate the existence of a net-
work of filaments, traversing the substance
of the protoplasm. In most cells, we also
find one or more of those bodies which are
termed nuclei, often attached to some jiart
of the cell-wall ; in these again, a network
of fibres is stated to occur. The nuclei con-
tain nucleoli. The cell-contents likewise in-
clude, in particular structures, products of
secretion— matters separated by the cells
from the circulating fluid, as in the cells of
the renal epithelium, &c., — also crystals,
pigment, &c.

The /or??JS presented by animal cells are
not so varied, or generally so geometrical,
as those occurring in the cells of vegetables.

In regard to size, the largest are the yelk-
cells of ova, especially of Birds and Reptiles,
and of some animals consisting of a single
cell, as certain of those curious organisms
the Greyarince.

The nuclei are usually spherical or lenti-
cular, non-contractile, transparent, and co-
lourless or yellowish. They are sometimes
solid or homogeneous ; at others they are
vesicles, with a very delicate membrane.
They sometimes contain, exclusively of the
nucleolus, a transparent colourless or yel-
lowish liquid, in which water and acetic
acid produce a precipitate of gramdes re-
sembling those existing in the cell-contents ;
hence in the ordinary manner of examining
them they seldom present their natural
transparency. The nuclei seem to be se-
creted or formed by the protoplasm, and
are regulators of the vital plienomena.

The nucleoli are roimded, well defined,
very minute, sometimes immeasurable.

Chemically, the cell-membrane ordinarily
consists of a proteine compound; it is mostly
dissolved, or rendered so transparent as to
become invisible, by acetic acid and solution
of potash ; thus differing in a striking man-
ner from that of vegetable cells. Cell-mem-
branes composed of cellulose occur in some
animals, as in the Tunicata &c. ; it is de-
tected here, as in plants, by the action of
iodine and sulphuric acid. The nucleoli

consist also of a proteine compound ; they
are soluble in potash,' but not in acetic acid.
The action of potash distinguishes them
from globules of fat. The carmine-am-
monia solution has a much more rapid and
powerful dyeing action upon the protoplasm
and the nuclei than upon the cell-walls.

It must be remarked that the appearances
interpreted to be nuclei and nucleoli are
frequently not respectively identical in
kind; the nuclei are sometimes homogene-
ous, at others true cells; sometimes they
relate to the formation of the cell ; at others
they are young secondary cells, vacuoles,
&c. ; the same applies to the nucleoli. These
important points have not hitherto received
sufficient attention.

Cells, or rather their protoplasms, are en-
dowed with peculiar vital forces, by which
they are capable of free movement, absorp-
tion, and the elaboration of the absorbed
matter; of growth, reproduction, and of
secretion. The entire organism of the higher
and most of the lower animals consists, at
a certain period of life, of cells, but some-
times of protoplasm alone.

Formation of Cells. — Cells are formed in
two ways : either from a blastema, proto-
plasm, or formative substance existing with-
out, or contained within, other cells. The
protoplasm is a semifluid substance, consist-
ing of proteine or albuminous matter, fatty
matter and salts.

The formation of cells in a free blastema
is not a general process ; in fact, its occur-
rence is now mostly denied. The only in-

Fig. 104.

Magnified 350 diameters.

Contents of a Jliilpighian body from the spleen of an
01. a, small, b, larger cells; c, free nuclei.

stances of its supposed occurrence in man
and the higher anim;^ls were in the forma-
tion of the chyle and lymph corpuscles, the
cells of certain glandular secretions (seminal
cells, ova), and glandular organs (the closed
follicles of the intestine, the lymphatic
glands, the splenic corpuscles with the
splenic pulp, and the thymus) ; lastly, of
the cellular elements in the impregnated
uterus, in the corpus luteum, the marrow of
foetal bones, and in the soft ossifying bias-

CELL.

[ 130 ]

CELL.

teniata. In the case of the chyle and the
spleen, at tlie commencement of cell-forma-
tion, there occin- ronndish,apparentlv homo-
geneous bodies of 1-11000 to l-rjGOU" dia-
meter, which, increasing in size, soon appear
distinctly as vesicles (tig. 104), and, on the
addition of water, exhibit an internal large
body resembling a nucleolus, as also several
granules. The minute details of this stage
of the process of formation are not accu-
rately known. As soon as the nuclei are
formed, cell-membranes are formed around
them, but not always in the same manner.
Sometimes the cell-wall is deposited directly
around the nucleus, so that it is but little
larger than the latter; at others the nucleus
becomes surrounded by a larger or smaller
quantity of protoplasm which becomes more
sohd. and around which the cell-membrane
is subsequently deposited. The latter oc-
currence has hitherto only been satisfacto-
rily observed in the case of the ovum, in
which the germinal vesicle, i. e. the nucleus
of the ovum-cell, which is formed first,
becomes surrounded by a quantity of yelk,
before the vitelline membrane is formed.
On the other hand, the formation of the
cell-wall directly around the nucleus has
been supposed to take place in all the other
localities mentioned above ; and to be espe-
cially shown by the occurrence of free
nuclei and larger cells, together with very
small cells closely surrounding the nuclei,
or separated from them by a slight interval
only. It is possible that, in this instance
also, the cell-membrane, even at its first for-
mation, may be separated from the nuclei
by a quantity of protoplasm too minute to
be detected.

The free formation of cells has been ob-
served by Weissmann in insects during de-
velopment.

The extracellular formation of cells is
unknown in plants. And probably, when
observers are agreed, it will be found that
all protoplasts and cells are deiiAed from
parent protoplasts by some form of segmen-
tation.

The endogenous method, or the formation
of cells within others, is very common, and
may be readily observed in the tissues of
embryos. In the most ordinaiy foi-m of this
kind of cell-formation, an original or parent-
cell produces within it two secondary cells,
which from the first completely fill it. The
first phenomenon observed in the parent-
cell is the increase of the nucleus, which
acquires two nucleoli, becomes elongated

and resolved into two nuclei. After this
the nuclei separate from each other, and a
partition is formed between the cells, di-
viding the parent cell into two perfectly
distinct spaces, each of which encloses a
nucleus and half of the contents (fig. 100).
The exact manner in which the increase of
the nucleus occurs is not certain ; but it ap-
pears that the nucleoli always become re-
solved into two by subdivision, and then
separate from each other. In the nuclei,
which at the same time become elongated,
the first trace of division is then usually a
median partition, which in favourable in-
stances appears to arise from the presence
of two secondary cells in close contact by
plane surfaces and entirely filling up the
parent nucleus. Very frequently nothing
is seen but first an elongated nucleus with
a partition and two nucleoli, and then two
hemispherical nuclei in contact by their
plane surfaces (fig. lO.o), no endogenous

Fig. 105.

Magnified 350 diameters.

An elongated nucleus, and one containing two secon-
dary nuclei, from the ovum of an Ascaris dentata.

nucleus-formation being perceptible ; in this
case, division of the nucleus has taken place,
the parent-nucleus containing two nucleoli
becoming finally resolved into two by a
deeper and deeper constriction. This mode
of cell -formation is often continuously re-
peated, frequently so long as the growth of
the organism continues. The parent-cells
then either continue their existence as such,
or they disappear sooner or later as histo-
logically distinct formations, and become
consolidated with the substance connecting
the ceUs.

The endogenous cell-formation, which
agrees essentially with the formation of
cells in a free protoplasm, is well estabhshed
in the case of the young cartilages of all
animals ; it also probably occin-s in embry-
onic organs in general, in which, from the
period at which they consist of true cells,
the entire growth depends upon the multi-
plication of the existing cells without free
cell-formation. It also occurs in patholo-
gical products, as in cancer.

In addition to this — the most common

CELL.

[ 140 ]

CELL.

kind of endogenous cell-formation, there are
others, viz. : —

a. In the ora of most animals at the earliest
period of development, a peculiar process
occurs called the segmentation of the jelk,
which must be regarded as preliminary to
the formation of tlie first embryonic cells;
and which, as the ovum bears the import of
a simple cell, falls under the type of endo-
genous cell -formation. The essential fea-
tures of the segmentation are as follows.
After the original nucleus of the ovum-cell
— the germinal vesicle — has disappeared in
consequence of impregnation, the granules
of the yelk no longer remain aggi-egated
into a compact mass as before, but become
distributed throughout the entire cell. The
first sign of commencing development is
then constituted by the formation of a new
nucleus — the first embryonic niicleus,around
a new nucleolus, which acts as a centre of
attraction to the yelk, and causes it to re-
unite into a globular mass — the first glo-
bule of segmentation. In further develop-
ment, two new nucleoli are formed from the
first nucleus by endogenous growth, which,
as soon as they are set free by the develop-
ment of the parent nucleus, become separate
from each other, act as new centres to the
yelk-granules, and thus the first globule of
segmentation becomes resolved into two.
The increase of the nuclei and of the glo-
bules of segmentation continues in the same
way, the first always preceding, until a very
large number of small globules are present,
which entirely fill up the yelk-cell ; some-
times, but exceptionally, the globules are
not resolved until the nuclei have become

Fig. 106.

Fig. 107. Fig. 108.

Magnified :!50 diameters.

Three ova of an Ancaris nigroreiwsa : 1, in tiie first'
2, in the second, nnd 3, in the third stage of segmenta-
tion, wilh two, four and sixteen segmentation-globules.
a, outer coat of the ovum; ft, ecgmentation-globiiles.
In 1, the nucleus of the lowest globule contains two
nucleoli ; in 2, the lowest globule two nuclei.

increased to three or four, so that three or
four globules are formed from each, instead
of two. This process is termed total seg-

mentation, because here the entire yelk is
applied to the newly-formed nuclei : partial
segmentation agrees with this in all essen-
tials, and only dilfers from it in the circum-
stance that in it, not the whole of the yelk,
but a larger or smaller part of it, varying in
different animals, envelopes the nuclei in
process of formation (figs. 106-108).

When the process of segmentation has
reached a certain stage, the segmentation-
globules become surrounded with mem- ,
branes and form true cells, whence it ap-
pears justifiable to arrange this process with
endogenous cell-formation. In fact it is
nothing more than a preliminary to cell-
formation in the ovum-cell, and only differs
from the ordinary phenomena of this kind
in the circumstance that — first, the nucleus
of the parent-cell or the germinal vesicle in
most cases has nothing to do with it ; se-
condly, the parent-cell itself persists ; and,
thirdly, the portions of the contents formed
in it by the successive increase of nuclei do
not assume the form of cells until subse-
quent generations. This view is moreover
justified, since the cells formed from the
last segmentation-globules continue for a
long period to multiply by endogenous pro-
duction (or division) ; and the entire seg-
mentation-process may be regarded as a
kind of endogenous cell-formation, in which,
on account of the rapidity with which the
nuclei increase, in the first generation of
globules it does not come to the formation
of membranes (see Ovum).

b. In some respects allied to segmentation,
are those forms of endogenous cell-forma-
tion in which a greater or less number of
secondary cells are formed within persistent
parent-cells, as seen here and there in carti-
lage, the suprarenal capsules, the pituitary
body. Sec. In this case, either two second-
ary cells are formed in the usual way in a
cell, almost or entirely filling it, and from
these other generations, either free or all or
individual ones enclosed in parent-cells of
the second and subsequent generations, or
only one secondaiT cell is formed in a cell,
whence cell-formation then proceeds in
either manner (fig. 109), or the secondaiy
cell is formed in a bud-like protrusion of the
parent-cell (see Echikococcus).

The formation of a larger number of
nuclei within cells, which frequently pre-
cedes cell-fornuition, but may also exist
alone, may be well arranged under endo-
genous cell-growth. Even in ordinary en-
dogenous cell-fonnation (and also in seg-

CELL.

Fig. 109.

L 141 J

CELL.

Fig. 110.

i; ■■

Magnified 350 diameters.
Cartilage-cells from a fibrous Telrety articular car-
tilage of the condyle of a human femur ; all lying iu a
flbi-ous basis, and easily isolated, a, single cells, with
or without thickening "of the cell-wall, and one or two
nuclei: 6, secondary cells, or cells of the first genera-
tion, with one or two nuclei — one, two, five, and many
cells in the parent-cells 6'; c, cells of the second gene-
ration, one to three in those of the first, hh\ c/, free
group of secondary cells.

mentation) -sre not unfrequently find three
and four nuclei in one parent-cell, so that
then, instead of two, a larger number of se-
condary celLs are formed at once, as e. g. in
the liver-cells of embryos. In certain ani-
mals ( CucuUanus, Ascaris clentata, Disfoma,
and the Cestoidea), instead of segmenta-
tion-globules, in the first stage of develop-
ment, nuclei only are formed in the ovum-
cell, which do not become surrounded by
cell-membranes until they have accumu-
lated into a large heap by successive endo-
genous growth. The same appears to take
place in the cells of the germ of the Crus-
tacea, in which from ten to twenty nuclei
frequently exist. The numerous nuclei,
however, in the seminal cells of most ani-
mals appear usually to have no connexion

Magnified .350 diameters.
Ivory-cells from the tooth of a dog.

with cell-formation, because the
seminal filaments are developed
within them; and the same applies
to those cells of the lower animals,
the numerous nuclei of which are
converted into urticating organs.
Whether in these cases the nuclei
' multiply by division or endogenous
growth is unknown.

Cell-formation hy division has been ob-
served" in the coloured blood-corpuscles of
the embryos of Birds and Mammalia, and
the earliest colourless blood-corpuscles of
the larvae of frogs (tadpoles) ; it also pro-
bably occurs in the colourless blood-cor-
puscles of embiyos and the chyle-cor-
puscles of adult Mammals. In all these
cases the cells first become elongated, and
the single nuclei appear to become divided
into two ; the cells are then constricted in
the middle and finally resolved into two,
each with a nucleus (PI. 49. fig. 36).

A peculiar kind of cell-gr-owth, most
nearly allied to di\'ision, occurs in the cells
of the ivory of the teeth ; in which the nu-
clei, while continually elongating, enlarge
from time to time and become constricted,
so that whilst that portion next the ivory
ossifies, the remainder serves to a certain
extent as a reserve for the subsequent for-
mation of newly ossifying portions (fig. 110),
The term cell is frequently used in a
totally difierent sense, to denote a partially
closed space, or the cup-like body enclosing

CELL.

[ 142 ]

CELL.

the space ; as in the case of the cells of a
Polype, or Polyzoon, the cells of a sponge,
&c.

BiBL. Treatises on Physiologif ; Schwann,
Einstimmioni (St/d. Soc.) ; id. Waffner's
Physiol. ; Valentin, Phys. ; KoUiker, Ge-
webelehre d. Menschen (and the Bibl. there-
in) ; Siebold, Zeitschr. f. ivissens. Zool. i.
p. 270; Ptollett, Sf richer' s Handbuch (Syd.
Soc.) i. ; Frey, Histolor/ie, and the Bihl.) ;
Cohnheim, Virchoio's Archiv, xl. ; Reck-
linghausen, ibid, xxviii. ; Weissmann,
Zeitsch. f. rat. Med. 3rd ser. xv. ; Klein,
Qu. Mie. Jn. 1878 and 1879, and Hist. ;
Carpenter, Phys. ; Strassburger, Zeltenbil-
dung, 1880; and the Bibl. of Tissues.

CELL, Animal, artificial formation of. —
When oil is immersed in a liquid containing
albumen, it becomes surrounded by a layer
of coagulated albumen, forming a cell ; and
this cell will exhibit the phenomena of en-
dosmose and exosmose in the same manner
as any natural cell. The same phenomenon
has been observed with metallic mercury and
albumen, chloroform and albumen, chloro-
ftjrm and chondrine, &c. It has not yet
been satisfactorily explained. The natural
formation of cells has been supposed to be
produced by this method ; but it appears
inapplicable to the purpose, as the nuclei or
masses of blastema, around which natural
cells are formed, do not consist of fat.

See Concretions.

Bibl. Ascherson, Miiller's Archiv, 1840,
p. .44, &c. ; Wittich, De hymenogonia albu-
minis, Eegiomout. 1850 ; Harting, Neder.
Lane. Sept. 1851 ; Melsens, Bull, de VAcad.
de Belg. 1850 ; Panum, Archiv f. path. Ati.
iv. 2 ; Bennett, JEd. Mn. Jn. viii. 16G ; Kiil-
liker, Geweb. d. Mensch. 10 ; Schmidt,
Taylor's Scientific Memoirs, v. 10.

CELL, Vegetable. — The definition of
the term cell in Tegetable anatomy, ordina-
rily adopted, is, a closed sac composed of an
(originally) imperforate membrane formed
of the chemical substance called cellulose,
this membrane enclosing more or less fluid
contents so long as the ceU retains its vi-
tality. All the solid permanent structures
of plants are formed of cells answering to
this character, the differences of the full-
grown tissues depending upon peculiar
modifications and alterations of the original
cells. In animal structures, the term cell
is commonly applied, not only to structures
really analogous to the cells of plants, but
also structures analogous to the contents of
the true cellulose plants, which, however,

are indeed in all cases the important vital
parts of the structure. All young vegetable
cells contain a quantity of semiiiuid nitro-
genous formative substance called proto-
plasm, which may be chiefly adherent as a
thickish and more or less continuous layer
on the inside of the cellulose wall, forming
a kind of lining to it, and therefore en-
closing all the rest of the contents, in which
case it forms the primordial utricle of Mohl ;
or this dense protoplasm may fill up the
whole cavity of the cell as a gelatinous
mass. Or the gelatinous mass of proto-
plasm may emerge from the cellulose sac,
with a definite form and organization, fur-
nished with cilia enabling it to move freely
in water ; and here the protoplasm presents
itself as independent, and indeed as the pri-
mary element of all cellular tissue : it occurs
in this condition in the zoospores of the
Confervoid Algne. These free bodies, de-
void at first of a cellulose wall, are evidently
analogous to the corpuscles of ' sarcode '
constituting certain animals, such as Amoeba,
while the cartilage-cells &c. of animals are
analogous to the cellulose sacs of plants.

In this work, then, the word cell, as ap-
plied to organic structures, is always used
in its ordinary sense. Hiickel's unnecessary
terms Cytode for the simple protoplast, and
Cell for the nucleated protoplast, are ignored
in botanical works.

Form. — Cells may present almost every
possible modification of form ; and this
depends on two sets of conditions — the ori-
ginal development and shape, and the mode
of growth and expansion. It is frequently
stated that the primary form of all vege-
table cells is that of a sphere, or at all events
that this is the type, from which all the others
must be considered deviations. This is true
only so far as it is intended to signify that
most cells which originate free in the midst
of fluid, suffering no external compression,
have a globular form ; and that in numerous
cases where cellular tissues are very lax and
free to expand in all directions, the compo-
nent cells acquire a globular form during
the enlargement to their full size. But in a
very large majority of cases the cells do not
originate in a free condition, they are pro-
duced by subdi\ision of older cells, and
consequent^, when first developed, they
have the shape of the half, the quarter, or
whatever segment it may be. of the parent-
cell ; moreover, in a majority of these cases
the mode of expansion also depends upon a
special law of the particular tissue, or even

CELL.

C 143 ]

CELL.

of such tissue in the particular group to
which the plant belongs, and not upon any
general law of globular expansion. The
above law does prevail widely in some fami-
lies, as in the Fungi ; and we very frequently
see it prevailing in pith up to a certain period :
but it will not hold as a general rule ; for the
lax tissues of leaves, of succulent stems, &c.
offer most strildng deviations, as do also the
vai'ied and often elegant forms of lower
Algae. It is frequently stated in books,
that the effect of pressure on cells having a
tendency to become globular, is the produc-
tion of a dodecahedral form ; but this again
is far too sweeping a generalization, and the
real fact is that globular cells of equal size,
expanding in a confined space, often become
twelve-sided by mutual pressui-e ; but far
more often the cells of a tissue are of diverse
size, and hence a polyhedral form is much
more common (tig. 111). Cells may be

Fig. 111.

globular, as in the Yeast-plant, and many
lower Algse, in the lax tissue of young pith
of many Dicotyledons (PI. 47. fig. 14), &e. ;
oval, as is much more common in parencliy-
matous tissues ; squarish, as in cork (PL 47.
figs. 16, 17) ; or tabular, as in the epidermis
of numerous plants, under which circum-
stances the side walls may be square,
rhombic, hexagonal or irregular, as in many
petals ; and the outlines may
also be undulated or even Fig. 112.
beautifully zigzagged, as in /X^_^
the leaf of Hellehorus fcetidus .S^
&c., the petals of many -
flowers, or in the leaf of the
Pineapple (PL 47. fig. 15),
&c. ; while the upper exposed
face may be flat or vaulted,
as in most petals, or even
papilliform, as in the petals
of the Sweet William and
of most flowers with glisten-
ing surface. Cells may also be cylindrical,
and then either with flat ends (fig. 112),
as in the parenchyma of many Monocoty-
ledons and in the filaments of Confervae, or

rounded ends or attenuated ends, as in wood
and liber tissue generally ; or they may
be prismatic, and then square or six-sided,
as in stems of most herbaceous plants ;
spindle-shaped, as in a largo number of
woods, such as that of Conifers, Box,
&c. ; and, in fact, of almost every con-
ceivable form. In lax tissues, the walls
of the cells often grow very unequally at
different points, wheuce result angular pro-
jections, by which the cells ordinarily co-
here (tig. 113) ; or these grow out into
arms or rays, producing stel-
late cells, as in the pith of
the Rush (PL 47. fig. 18),
and the parenchyma of many
aquatic jalants, in the leaf-

Fig. 113.

^

stalk ot the Banana, &c. t^^ )'
Cells which are free, as in *"^^ ^ ■
the lower cellular plants, ^
sometimes grow out into ^
lono' tubular structures such

as

Vaunkeria, with a conti-

nuous cavity, and indeed sometimes ramify
into a complication of branches, as in Brt/-
opsis and C'odium, while in Botnjdium (fig.
7o) the globular cell sends down a number
of root-like filaments Avhicli are mere pro-
trusions of its own wall. The cells of Chara
attain very large size. In the Flowering
plants we have an example of extraordinary
growth of a single cell in the pollen-tubes,
which, in some cases, become as much as
three inches long.

•SV^e.^The dimensions of cells vary to
infinity, and, indeed, often extremely in one
and the same tissue, but not as a rule. And
the diameter of cells is very frequently in-
comparably less than the length, as in all
filamentous and fibrous cells. Taking a very
general view, we may sav that parenchyma-
cells vary from l-2o0 to 1-1000" in dia-
meter ; but the spores of many Fungi mea-
sure no more than 1-0000 to 1-8000", while
the cells of the juicy parenchyma of many
fruits and piths attain as much as 1-100".

The smallest cells appear to occur in
Talmella hyalina, where they measure the
1-83,000". In elongated cells, such as those
of liber and most woods, the diameter is
ordinarily less than in parenchyma, while
the length is far greater: thus in wood the
length varies from about 1-40 to 1-12",
while the diameters are respectively 1-300
and 1-100"; in liber the length may extend
to 1-8 or 1-4", with a diameter of 1-800 and
1-400". (See Fibres.) Hairs composed
of a single cell often attain a great length,

CELL.

[ 144 ]

CELL.

as in Cotton, where a single filamentous
cell may measiu'e 1 to 2". (See Tissues,
Vegetable.)

Cells may be examined either in situ, as
parts of tissues, or free, separated naturally
or artificially. For the lirst it is simply
requisite to make fine slices with a razor, in
various directions through the structure ; if
soft or thin, it should he placed between the
two halves of a split vial-cork and sliced with
the cork, the cork being afterwards removed
from the slide with a needle. Slices of many
kinds of cellular tissue are made more clear
by the addition of a little diluted sulphuric
acid, which, however, often swells up some
of the layers.

For examining isolated or nearly separate
cells, we may take the lower Algae or Fungi,
or germinating spores of the higher plants,
or we may separate the cells of the tissues of
higher plants. The parenchymatous tissues
may usually be separated into their elemen-
tary cells by maceration in water : the de-
composing ends of floAver-stalks which have
been in water several days will generally
afford tissue in such a state that it may be
broken up with a needle ; in the pulp of ripe
fruits, such as currants, strawberries, &c.,
mere pressure separates the cells. Boiling
will do with some of the denser kinds ;
while for the woody tissues it is requisite to
heat fragments with a particle of chlorate
of potash and a drop of nitric acid (or let
them macerate for 12 to 24 hours), and wash
them well with water: liber-cells, woody
cells, &c. may be isolated by this means ;
or still better by treating them with chromo-
sulphuric acid.

Formation of Cells. — This subject has
undergone a great amount of investigation
during the last few years ; and the views
which have been propounded at various
times have conflicted strongly in many
points. It would be exceeding our limits,
however, to enter upon a critical examina-
tion of the theories of cell-development;
and we shall therefore conlhie ourselves to
a brief account of those phenomena and
laws of the reproduction of cells upon
which the diversity of opinion only afl'ects
subordinate particulars.

All vegetable cells (using this term in the
sense of the cellulose sac loit.h contents, as de-
fined above) in which the capacity for repro-
duction exists, contain an internal structure
or protoplasm, varying in its condition and
appearance at different epochs and in dif-
ferent plants or parts of plants. This struc-

ture often forms a semifluid layer lining the
cellulose wall of the cell. All the other
cell-contents are enclosed or imbedded in
this protoplasm ; and with it they collectively
constitute what is called by some authors
the endochrome of the cell.

In a very large number of cases, we find
in the protoplasm at this time, a peculiar
body called the nucleus, to which some
writers attribute great importance in the
dovelopment of cells. Its nature is not
well defined ; but in the best-observed cases,
it consists of a small globular or lenticular
mass, apparently composed of the protoplasm
in a condensed and granular (solid) con-
dition. The nucleus is usually present in the
cells of the higher plants, but is often ab-
sent in those of the ThaUophytes. It mostly
exhibits one or more bright granules or
points in its substance, which are called
nvclcoli. Many authors consider this body
of the first importance in cell-development ;
but as we are by no means satisfied as to
the character of its agency, its peculiarities
and its relation to the cell are spoken of
separately under the head of Nucleus
(PL47. figs. 8,9 w).

The ordinary development of new cells
depends upon the division of the protoplasm
of existing cells into two or more portions,
which, becoming independent centres of
life, produce new cellulose membranes, and
become new cells. The phenomena in which
this law is manifested are far more varied
tlian would be iinagined from this simple
statement. The numerous subordinate mo-
difications, however, maybe arranged under
three principal lieads : — 1. Cell-division,
sometimes called ;«f/7'sw;«^/c cell-formation;
2. Cell-division with liberation of the new
cells ; 3. Free cell-formation.

1. Cell-division is the process which occurs
in all reproduction of cells connected with
vegetative growth or increase of the mass of
existing structures. This is the manner in
which the cells are multiplied in the growth
of the thallus of the interior plants, and in
the growth of the stems, leaves, roots, and
other organs of the higher plants. It occurs
also in the formation of the basidiospores or
sti/loKpores of Fungi, the spcrniiifi'a of these
and Lichens, of (/ontdia in the Lichens, and
conidia in the Fungi. The essential fact
observed in all the cases is, the division of
the protoplasm of the parent-cell into two
or more distinct portions, each of which
secretes a layer of cellulose over its whole
surfece ; and thus, when the two are in ap-

CELL.

[ 145 ]

CELL.

position, a partition i,« formed dividing the
pavent-coll into two or more parts. The
form of tlie secondary cells depends of course
on that of the parent-cell at the time of
division. In the case of cellulose tissues,
such as those in the pvnclum irf/efafionis of
the buds of the h igher plants, in camhitrm ,k c,
the division is ordinarily into two parts,
which respectively grow until equal in size
to the pirent ; and either both or only one
of these divides again in the same way, and
so on, luitil the whole structure is com-
pleted. It is evident that the external
forms of all cellular structures must depend
greatly upon the laws of division of the
cells of plants. For example, supposing we
start from a single square cell, when this
divides into two halves, and these grow to
equal the parent-cell, we have an oblong
figure ; if the half-cells divide again in the
same direction, we shall in time get a long
filament ; and if both new cells divide again
each time, the filament will grow much
longer in a given time than if only the end-
cell continually divided, leaving one new cell
behind it at each division. If the pair of
cells produced by the first halving divide at
right angles to "the first division, a square
gi-oup of four cells results ; and if this law
continues to act, a flat plate of cellular tissue
will result. Further, if the cells also divide
by horizontal partitions ( in the third direc-
tion of space), the mass of cells will gradually
acquire thickness or height as well as length
and breadth. Lastly, if the cells of parti-
cular regions cease to divide sooner than
others, irregular or complex but definite
structures w411 be produced — as those parts
where the cell-division goes on will emerge
from the general mass, in the Cellular plants
as lobes, and in the higher plants as conical
bodies which are gradually developed under
similar laws into the organs. The diver-
sities of internal organization depend also
to some extent on the same laws, but less on
these than on the laws regulating the forms
which the cells acquire when fuU-grown.

Cell-division may be observed most easily
in the lower Cellular plants, or in the simpler
structures (such as hairs) of the higher plants
(PI. 47. figs. 8, 9). The Confervfe afford
exceedingly favourable opportunities, as do
also the filamentous or thalloid structures
of germinating Mosses, Ferns, microscopic
Fungi, t&c. The behaviour of the parent-
cell before division exhibits some diversities.
If a simple filament is increasing by cell-
division, the cylindrical parent-cells merely

elongate a little before dividing transversely.
If the filament is to branch, the wall of the
parent-cell bulges out gradually at the point
where the branch is to appear ; the bulging
soon becomes a pouch, and this pouch is
soon shut off" by the formation of a partition
at its base. Bead-hko rows of cells Ukewise
divide by budding in this way, as may be
observecl, for instance, in the Yeast-plant :
the new cell first appears as a little 'bubble'
on the side of the parent, with its cavity
continuous; and after it has acquired a
certain size, its protoplasm detaches itself
from that of the parent, and a partition is
formed at the point whence the second cell
emerged (PL 20. fig. 23).

Another point which must be noticed
here, is the question whether the parent
protoplasm divides instantaneously, at a given
epoch, into the new utiicles, or whether it
parts gradually, by a sort of constriction ad-
vancing from the surface towards the centre,
roughly comparable to what occurs when a
ligature is slowly drawn tight round an
elastic tube, or w^hen a bar of soap is cut in
two by passing a string round it and gra-
dually drawing the loop tight. It seems
probable that the segmentation of the pro-
toplasm is always gradual ; and it is certain
that it is so in many cases. Its gradual
constriction has been observed in those
Confervae where the protoplasm forms a
hollow sac, lining the whole internal sur-
face of the parent-cell ; it may be traced in
the larger Confervae, in Spirogyra, &c., by
keeping the plants growiug in water under
the microscope. It appears that the division
is generally completed during the earlier
hours of the morning.

2. Cell-division icith liberation of the new
cells. — The first step in this process is ana-
logous to what takes place at the outset in
the preceding set of cases; but we find
much more important modifications here.
This is the mode of development of spores
of the Ascomycetous Fungi, of the spores
and tetraspores of the Algae, the spores
of Lichens, the spores of all the higher
Cryptogamia, the active gonidia or zoospores
of "the Algte, the parent-cells of the sper-
matozcids or active spiral filaments of the
higher Cryptogamia, and of the pollen-grains
of the Flowering plants.

The general character is : Division of the
whole protoplasm into segments, which
either acquire a cellulose coat within the
parent-cell before they are set free by its
solution or bursting, or escape from the

L

CELL.

[ 146 ]

CELL.

parent-cell witliont a cellulose coat, and
secrete this afterwards.

The following modifications occur : —

a. Division of a nearly solid protoplasm
into four, either directly or by two
halvings. This occurs in the development
of pollen and of the spores of Mosses, Ferns,
&c. The parent-cells of the pollen or spores
become free in the interior of the anther or
sporange, by the solution of the walls and
septa of their parent-cells. The protoplasm
of the free cells divides into four segments,
entirely tilling the ceU. After this, either
partitions are formed between these (pollen-
cells), to be subsequently dissolved, or they
at once clothe themselves with a cellular
coat {Marchmitia). In either case, they
ultimately lie free in the parent-cell, which
is itself finally dissolved (PI. 47. figs. 10-13).

b. Division of a homogeneous protoplasm
into a large number of segments, each of
which acquires a cellulose coat, the whole
of the new cells lying closely packed but
free in the parent-cell. This occurs in the
antheridia of the higher Cryptogamous
plants, in the formation of the parent-cells
of the spermatozoids, also in the formation
of the parent-cells of the spores and the
elater-ceUs of the Ilepaticse. The formation
of the spores in the asci or thecae of the
Ascomycetous Fungi and the Lichens be-
longs either to this or the preceding case
(PI. 37. fig. 12).

c. Division of the homogeneous proto-
plasm into segments which do not acquire
a cellulose coat until after they are dis-
charged from the parent-cell. Tliis occurs
in the development of the zoospores of most
of the Coniervoidete {C/adop/ioj-a, Biyopsis,
AcJili/a, Ulothrix, &c.), where the primor-
dial utricles become free in the cavity of
the parent-cell when they divide, and break
their way out into the water, where they
form a cellulose coat after they have swum
about freely for some time by means of
their cilia.

d. Division of a sac-like protoplasm into
a number of portions, which appear at first
as papillffi on the walls of the cell, and
filially become isolated in the cavity. This
occurs in the development of the gonidia
of Hydrodictyon, Botrydium, &c. These
last two cases are connected with a and h,
by the circumstance that the zoospores or
active gonidia are replaced, under certain
circumstances, by cells ; that is, the bodies
produced in this way acquire a cellulose
coat before they leave the parent-cell.

Numerous intermediate conditions occur
which connect all these together ; and the
last case, d, does not difier essentially from
what takes place in the formation of the
endosperm-cells, placed under 3.

3. Free Cell- for mat iun. — Here the new
cell is formed by a portion of the parent
protoplasm separating itself from the rest
of the protoplasm, assuming a globular or
oval form, and secreting a cellulose mem-
brane upon its surface, so as to form a new
cell lying free in the cavity of the parent
primordial utricle. The most remarkable
instance of this case is the formation of the
germinal vesicles in the embryo-sac of the
Flowering Plants (PI. 47. figs. 1-4) ; but
this is denied by Strassburger. Other cells
sometimes occur, formed in the same way,
at the opposite end of the embryo-sac.
The embryo-sac also frequently becomes
filled, after fertilization, by a large increase
of free cells developed out of the layer of
protoplasm or primordial utricle lining the
walls; these {endosperm-cells) accumulate in
the sac, and sometimes become consolidated
into a tissue (albumen) in which the embryo
lies imbedded ; in exalbuminous seeds they
are re-absorbed during the growth of the
embryo. The embryo itself is developed from
the germinal vesicle by cell-division such as
is described under § 1 (PI. 47. figs. 5, 0).

Cell-formation also occurs, without divi-
sion, in cases where the entire contents of
a cell separate fi-om the parent, and form a
new organism (rejuvenescence) — as in Sti-
yeocloiniim., CEdvyoniiim, and other Con-
fervoid Algfe.

Here also must be referred the new cell-
formation resulting from Conjugation.

Karsten considers that the formation of
every cell within a living organ is original ;
and that the cell is not divided into two
new individuals by transverse septa or pro-
liferation.

The hypotheses of the independent origin
of cells from organic substances by generatio
a-quivoca seem to require no notice ; but
allusion may be made to certain curious
phenomena which have been called 'abnor-
mal cell-formations,' occurring in some of
the Confervoids. The protoplasm of the
Siphoneaj is very apt to collect into globu-
lar masses in injured filaments; and tluso
globular masses apparently acquire a cellu-
lose coat in some cases: they have been
observed in Vaucheria and Bryopsis ; a some-
what similar phenomenon often occurs in
the contents of the cells of iSpirogyra. It

CELL.

[ 147 ]

CELL.

appears to be a land of goniclial reproduction,
in wliicli portions of llie living- contents
are enabled to save themselves from the
general decomposition. (See Pseudogo-
NiDiA.) Some forms -tt-hich we incline to
refer here, have been described as distinct
genera and species of parasitic Algre ; on
this subject see Parasites, Chytkidiuji,
Pythium, and Amy'lobactee.

Memhraue. — Li all young organs of suc-
culent structures, and all tlie delicate tissues
of the higher plants, and in the majority of
the Cellular plants in almost the entire or-
ganization, the cellular membranes consist
of a thin structureless pelhcle, possessing a
considerable degree of toughness and a
certain amount of elasticity. (C. J. Agardh
has indeed asserted that cell-membrane is
composed of spiral librous structure ; but
this doubtless is an error as regards the pri-
mary membrane.) It is readily permeable
by vrater, while no orifices of any kind can
be detected in it ; but young, and indeed
soft cell-membranes generally, imljibe more
or less water, and swell to some extent,
often becoming more or less gelatinous. It
is stated by Schleiden that the membranes
of nascent cells are soluble in water, but
genei'al experience does not confirm this
statement ; the only approach to a corro-
boration of it that we have met with, is in
the lower Algte : the zoospores are often
extruded in the interior of an extremely
delicate sac formed of cellulose, which al-
most immediately vanishes and sets the
zoospores free. The external membranes
of many of the filamentous and unicellular
Algae become gelatinous, and giadually dis-
solve away as the inner membranes are
successively deposited, forming a gelatinous
coat, as in Prvtococcus, Nostoe, Desmidia-
ceae, Diatomaceae, Zyf/neona, Oscillatorieas,
&c. ; the same also takes place in the de-
velopment of spores and pollen-grains, which
are set free by the parent-cell membranes
becoming dissolved. This, however, is
scai'cely direct solution in water, and comes
rather under the head of decomposition.

Young and delicate cell-membranes are
perfectly transparent and colom-less, as is
seen in the Yeast-plant, in the mycelium of
Mildews, in the cellular tissue of tuberous
structures like the Potato, and in piths (after
the mucilaginous cell-contents have been
removed). As they gi-ow older, they often
become coloured, sometimes very deeply,
which is suppu.-ed, howcAer, to depend on
the infiltration of foreign matters. In the

state of simple cell- membranes, where no
infiltration of foreign matter has occurred,
the application of sulphuric acid of moderate
strength, with solution of iodine in solution
of iodide of potassium, brings out a bright
blue ciilour ; and this is regarded as a test
for cellulose, the universal basis of vegetable
cell-membrane.

When the cell has attained a certain age,
new deposits of membranous substance take
place inside; and the walls thus acquire
more or less thickness, together with a
very varied appearance, according to the
character of the deposits. The new layers
are known as Secondary Layers ; and the
term Cell-wall is perliaps the most conve-
nient collective term which can be applied
to the various structures produced by the
deposition of new layers of cellulose upon
the inside of the primaiy cell-membrane.
Although these new deposits are thin layers
of cellulose hke the primary membrane, they
are rarely so totally devoid of detail struc-
ture, and in the majority of cases exhibit
orifices and irregularities of the most striking
character. Moreover, in one class of cases,
they are not deposited as a continuous coat,
but as a fibrous structure applied upon the
primary membrane, as in spiral-fibrous cells;
and in wood-cells they are formed one within
another to such a thickness that the cell-
wall loses its original membranous character,
and becomes a solid case, with the internal
cavity reduced to a comparatively small
chamber in the centre.

The simplest condition of a thickened
cell-wall, is that met with in the unicellular
and filamentous Algfe, where the primary
membrane becomes coated in the interior by
successive continuous layers of cellulose
exactly resembling itself, and which often
indeed can only be known to exist by com-
paring the thickness of old and young cells,
since no lamellation can be detected ; gene-
rally speaking, however, the action of mode-
rately diluted sulphmic acid swells up such
membranes, and renders the lamellas more
or less distinct (Pi'. 47. fig. 24). The thicken-
ing layers of the unicellular and filamentous
Algte are scarcely to be compared with those
of the cells of higher plants, since they are
rather to be regarded^as the primary mem-
branes of new cells produced in the interior
of the older cells, in mauj' cases set free by
the solution of the latter. These cell-walls
sometimes exhibit peculiar fibrous appear-
ances. See Spiral Structvees.

These layers may be coloured blue by

l2

CELL.

[ 148 ]

CELL.

sulphuric acid and iodine; wlien very young,
even by iodine alone; but when old or where
they undergo spontaneous solution into a
kind of jelly, as in lilamentous Algse, this
celliUose reaction seems to fail — at all events
it is so uncertain in its behaviour, that,
although it gives a positive result in suc-
cessful cases, a negative residt is altogether
inconclusive.

In the cells of the generality of plants of
higher organization, the secondary cell-
membranes exhibit a striking difference
from the primary, inasmuch as we find them
constantly perforated by holes, slits, or
orifices of some shape, so as to leave the
primary membrane bare ; whence resvdts a
spotted or streaked appearance of the cell-
wall, as may be seen even in cells with the
walls still very thin, such as fully-formed
pith-cells of the Polder.

The earlier vegetable anatomists regarded
these spots or dots as orifices through the
cell- wall ; but they are in reality only j^its
opening into the cavity of the cell, and closed
externally by the original membrane of the
cell. "When the cell-wall becomes much
thickened, as in cells of horny albumen or
wood-cells, the layers successively deposited
over the inside mostly correspond pretty
exactly with the earliest layers, and leave
the spots always free, so that these become
gradually converted into tubular canals run-
ning through the thick cell-walls (PI. 47.
figs. 21-2o and 27). In the majority of
cases, but not in all, the spots or pits in the
cell-wall are opposite to similar spots in
the walls of the adjacent cells, so that the
cavities of the two contiguous cells are only
separated from each other by the primary
membrane of each, as at first, allowing free
permeation of fluid from one to the other.
In old cells these primary membranes be-
come destroyed, and thus the cavities
communicate freely through these canals
running out through their hard thickened
walls. The various complications of these
pits are spoken of under the head of Pitted

CELLS.

The secondary layers are further distin-
guished from the primary membrane by
the prevalence of a tendency to assume the
character of spiral bands or fibres winding
upon the original cell-wall. This may be
detected even in many cells which remain
quite membranous, as in some Confervce and
many hairs, also in pitted lignified cells,
where the thickening layer forms a general
coat upon the inside of the cell ; the liber-

cells of many plants exhibit a delicate spiral
striation of their walls, while some liber-cells
display it with especial distinctness. Some
of these cells give way in a spiral direction
when torn by pulling lengthwise. In par-
enchymatous cells this spiral structure is
often very fully developed in all its varieties ;
but it is especially characteristic of the
vessels and ducts ; while in certain woods,
as in Taxus, we have a combination of the
porous with the spiral secondary deposits,
the earlier thickening layers leaving spots
uncovered while the latter ones are deposited
along a spiral line coiling up the cell-wall
from bottom to top, and thus the cell
appears to have a spiral fibre lying upon its
walls. These structures are spoken of at
length under the heads of Splr^vl deposits
and Pitted cells.

Cellulose is distinguished, when in the
form of membrane or fibrous structure, by
the blue colour it usually assumes when
treated with iodine (starch differs in its
granular form and its solubility in acids and
potash, and its swelling up in hot water).
The nitrogenous protoplasm is always co-
loured yellow-brown by iodine. The blue
colour appears in many membranous paren-
chymatous tissues when the cells are soaked
in tincture of iodine, dried, and then wetted
with water. In other cases it is necessary
to apply dilute sulphuric acid and solution
of iodine simultaneously. It is sometimes
difficult to bring out the blue reaction in
old cells ; various methods are had recourse
to for this purpose. In corky or other epi-
dermal tissues, the blue colour of cellulose
may be brought out by soaking the cells for
twenty-four liom-s or more in strong solution
of potash, washing it well, soaking in tinc-
ture of iodine, drying, and then wetting with
water. Old wood-cells undergo the same
change by boiling in nitric acid, instead of
treating with caustic potash, and then
adding the iodine, &c. as above. All the
solid structures of cell-membranes yield to
one or other of these means, and exhibit
the blue colour with iodine, which, if not
indicative of a composition of cellulose,
points to a substance intermediate between
this and starch, produced out of the cellu-
lose by the chemical action. The most
characteristic property of cellulose, how-
ever, is its solubilit}' in ammuniin-et of
copper (Cellulose.) The cells of Fungi
and many Lichens and Algse do not exhibit
the ordinary reactions of cellulose, becoming
brown instead of blue with iodine and sul-

CELL-CONTENTS.

[ 1^9 ]

CELLULARIID/E.

Shui'ic acid, and they are moreover not
issolved by anunoniuret of copper ; while
certain cell-walls of Lichens are coloured
blue by iodine alone, from the presence of
granulosa. Cell-membranes and their mo-
difications are examined, of course, in
similar preparations to those mentioned as
displaying the forms &c. of cells.

further information will be given in the
articles relating to the structures into the
composition of which the cells enter.

BiBL. — General. Henfrey-Masters, Bo-
tany ; Mohl, Veget. Cell, tr. by Henfrey,
1853 ; Schacht, 'PJlanznizelle, Berlin, 1852;
Uuger, An. u. Phi/f. Pfunzen, \'ienna, 1855;
Meyen, PjianzenpJnjs. Phytutomie ; Morren,
Bull, de Px4.cad. de BntxeUes, v. No. 3 ;
Braun, Bejuv.(Ray Soc. 1853 J; Pringsheim,
Jahrb. wiss. Bot. 1858, i., ii. ; Mohl, Cellu-
lose, Bot. Zeit. V. {Scientijic Memoirs, 2nd
ser. vol. i. 90) ; Bot. Zeit. xi. 753; Harting,
Mulder's Phys. Chem. 1849 ; Bot. Zdt. v.
337; Kiitzing, Phil. Bot. 1852; Agardli,
Cell, veget. &c. 1852 ; Caspary, Streifuny
d. Zellemoand, Bot. Zeit. xi. 801 ; Criiger,
Primitive Fase.r, Bot. Zeit. xii. 57, xiii.
p. 601 ; Dippel, Veyetah. Zelleiibild. 1858 ;
Hofmeister, Pflanzenzclle, 1867 ; Karsten,
Ann. N. H. 1863 and 1864; Nageli, Mikr.
1877, 532 ; Sachs, Bot. 1874, 8. See also

PRniORDIAL UTKICLE.

CELL-CONTENTS.— This term corre-
sponds, in regard to vegetables, to the word
endochrome as used by Thwaites, Ralfs, and
some of the French botanists. It refers
here most essentially to the pi'otoplasm or
primordial utricle, as this is the part effec-
tive in development ; while the substances
imbedded in or lying in the cavity of this
are variable according to age, stage of deve-
lopment, &c. See Peimordial utricle.

CELLA'RIA = Salicornaria.

CELLE'PORA, Fabr.— A genus of In-
fnndibulate Polyzoa, of the suborder Chei-
lostomata, and family Celleporidye.

Distingmshed by the massive, globose,
and incrusting, or erect and branched,
calcareous polypidom, and the irregularly
heaped vasiform cells, vertical to the com-
mon plane, with a beak on one or both sides,
furnished with an avicularium. Seven
British species.

C. pumicosn. Rough, porous, massive ;
cells suborbicular, the mouth round. Com-
mon.

C. vitrina. Incrusting; cells ovoid, very
small, pearly, and irregularly arranged.

BiBL. Johnston, Brit. Zooph. 295; Gosse,

Mar. Zool. 17; Busk, Polyz. ii. 85 ; Paleont.
Soc. ( foss.) 1859 ; Ilincks, Polyzoa, 398.

CELLEPORELLA,Gray.— A genus of
Infundibulate Polyzoa, of the suborder
Cheilostomata, and fimily Porinidse.

Two species.

BiBL. Hincks, Polyzoa, 413.

CELLEPO'RID.E.— A family of Infun-
dibulate Polyzoa (Bryozoa), of the suborder
Cheilostomata.

C/iar. Those of the single genus Cel-
lepora.

CELLULAR TISSUE, of Animals.
See Connective Tissue.

CELLULAR TISSUE, of Plants. See
Tissues, Vegetable.

CELLULA'RIA, Pallas.— A genus of
lufundibulats Polyzoa (Bryozoa), of the
suborder Cheilostomata, and family Cellu-
lariidfe.

Distinguished by the jointed, branched,
erect polypidom, with flat, linear branches ;
the contiguous cells in two or three rows,
perforated behind, and more than four
between two joints; and the absence of
avicularia and vibracula. One British
species :

C. Peachii (Cellularia Peachii, var., John-
ston). Cells narrowed downwards, truncate
and somewhat rounded above ; usually a
small spine at the upper and outer angle ;
three to five perforations behind ; orifice
oval, regular ; margin somewhat thickened,
minutely granular ; ovicell globular with a
tessellated surface. On stones &:c. from
deep water.

C. ciliata (Johnston) = Bicellaria oil. ; C.
avicularia =^ Buy nia avic; C. ternata=Me-
nipea tern. ; (,'. scruposa = ScrupoceUan'a
scrap.; C.7'eptans=Cand(irept.; C.Hookeri
= Cnherea Hook. ; C. neritina = Buyula ner. )
C. plumosa = Buyula j)lu7)i.

BiBL. Busk, 31ar. Polt/z. 20 ; id. Ann.
Nat. H. 1851, vii. 82 : Hincks, Polyz. 33.

CELLULA'RIID.E.— A family of In-
fundibulate Polyzoa (Bryozoa), of the sub-
order Cheilostomata.

Distinguished by the branched, erect
polypidom, and the flat, linear branches,
with the cells in one plane. Genera :

Cellularia. Cells in two or three rows,
contiguous, perforated behind, more than
four between two joints ; no avicularia nor
vibracula.

Menipea. Cells oblong, narrowed down-
wards, not perforate ; one or two avicularia
below the orifice in front.

Scrupocellaria. Cells with a vibraculum

CELLULOSE.

[ I'^O ]

CEMENTS.

behir.d, and a sessile avicularium at the
upper and outer angle ; orifice spinous.

Canda. Cells with a vibraculiun iu a
notch on the outer side ; no avicularium at
the upper angle.

BiBL. That of the genera.

CEL'LULOSE. — The proximate princi-
ple of which the permanent cell-menibraues
of plants are always composed ; it occurs
also in some structures of certain animals,
as the mantle of the Tunicata, the skin of
the silkworm, the elytra of some insects, the
tegument of some Crustacea, &c. In plants,
its physical characters differ very much iu
different cases; sometimes it is exceedingly
soft, and at once acquires a blue coloiu*
Avith iodine (amyloid ?). Usually it be-
comes blue when soaked in tincture of
iodine, dried, and then wetted with water.
In other cases it is more dense, and does not
become coloured blue with iodine until after
treatment with sulphuric acid, when it be-
comes more or less bright blue (the ordinary
test for cellulose) . Occasionally this reaction
gives a purplish colour. In old, infiltrated,
or greatly consolidated cellulose structure,
this test gives only a yellow-brown colour ;
but boiling iu nitric acid (for woody tissues)
or solution of potash (for epidermal tissues)
will generally bring the cellulose into a state
in which, if wetted with tincture of iodine,
dried, and then Avetted with water, it turns
blue. The blue colour is produced in some
resisting kinds of cellulose by a solution of
iodine in chloride of zinc or by iodide of
zinc. (Schulze's Test.) Sulphuric acid
swells and dissolves cellulose ; solutions of
potash and nitric acid do not act so quickly,
especially the latter. But the best test for
ordinary cellulose is the amnioniuret of
copper, which quickly dissolves it. Care
must be taken in testing for cellulose with
iodine, that no extraneous matter lodges
on the preparation ; fragments of cotton,
blotting-paper, &c., consisting of cellulose,
might give rise to error. Minute crystals
of iodine precipitated from the tincture will
give the object a bluish tint.

In the Tunicata, the intercellular sub-
stance consists of the cellulose, not the
cells (Sc/ic/cht).

BiBL. See Amyloid and Cici-t.-ajem-
BTtANES. Schaeht, ]\Iiiil. Arc/iiv, ISol ( Qh.
3Iic.Jn. 1802, pp. .34 and lOG); Huxley,
Qm. Mic. Jn. ]8o2, p. 22; Schmidt (Tay-
lor's Sa'eni. Mem. v. p. 1) ; KiJlliker and
Linvig, Ann. Sc. N. Zool. 184(5, p. l!):l;
Yirchow, Compt. Mend. 1S53 (Ann. N. II.

xii. p. 482) ; Schweitzer, Chem. Gaz. xvi.
60, .3.30 ; Gmelin, Ilimdh. d. Chem. vii. 574 ;
Hancock, Linn. Proc. 1807.

CEMENTS. — These are used for closing
the cells in which microscopic objects are
placed for preservation ; also for fastening
pieces of glass to each other, to form cells,
&c. Those, the method of making which
we have not described, can be procm-ed at
any oil-shop.

AspJialt-varnish consists of a solution of
asphalt (must be real) in boiling linseed-oil,
or oil of turpentine, or iu a mixture of the
two ; it should be cream3\

Black Japan consists of asphalt, gum
anime, amber, linseed-oil, and oil of turpen-
tine.

Brunswick hJack consists of asphalt, dry-
ing linseed-oil, and oil of turpentine.

Asphalt dissolved in benzole.

Canada balsam : a. alone ; b. digested
with sufficient ether, benzole, or chloro-
form, to render it slightly more fluid.

Electrical cement : a. is made by melting
together 5 parts of rosin, 1 part of bees'-
wax, and 1 of red ochre, b. The addition
of 2 parts of Canada balsam renders this
cement much more strongly adhesive to
glass.

Gold-size may be prepared by boiling 25
parts of linseed-oil for three hours with 1
part of red lead and ^ of a part of umber ;
then pour oft". Successive portions of a
finely powdered mixture of equal parts of
white lead and yellow ochre are then added
to the oil, being well rubbed and mixed with
it, until a tolerably thick liquid is formed ;
this must be once more thoroughly boiled.
It is also sidd.

Da mmara- resin, is often used, dissolved
in benzole ; a third of gold-size is an advan-
tage.

Gutta-jyercha cement is made by adding
15 parts of oil of tui-pentine to 1 part of
finely cut-up gutta percha, and dissolving
by the aid of a continued heat and stirring.
The solution is then strained through a cloth.
In the strained solution, 1 part of shell-lac is
then dissolved by heal and stirring. The
application of the heat is continued until a
drop of the solution let fall upon a cold sur-
face becomes nearly hnrd. It can be ren-
dered thinner by the addition of more oil of
turpentine.

Alarine f/lue consists of caoutchouc and
shell-lac dissolved in coal-naphtha by the
aid of heat. It is sold by microscope-
makers and those who mount objects.

CEMENTS.

[ 1'^^ ]

CEPHALOPODA.

Scallncj-ioa.v varnish. Prepared by arld-
ing enough spirit of wine to cover coarsely-
powdorod sealing-wax, and digesting at a
gentle heat.

Shell-lac varnish. Prepared in the same
manner as sealing-wax varnish, shell-lac
being substituted for the sealing-wax. 20
drops of castor-oil to the ounce is an im-
provement.

IJliife hard varnish consists of gum san-
darac dissolved in spirit of wine, and mixed
with turpentine varnish.

Bismidh-cement. Made by tbickening a
solution of mastic in chloroform with sub-
nitrate of bismuth.

India-rubber and asphalt. Made with
India-rubber -30 grs., asphalt 4 oz., mineral
naphtha 10 oz. l)issolve the caoutchouc in
tlie naphtha, then add the asphalt, and heat
if necessary.

JMiite lead mixed with drying linseed-
oil, and oil of turpentine (white paint).

Wlieat-paste shoidd have a few drops of
some volatile oil, or carbolic acid added to
it.

Giim-arabic dissolved in water, with a
small quantity of glycerine, and a few drops
of volatile oil.

Zinc-cement. This is made with oxide of
zinc, drying oil, Dammara-resin, and ben-
zoline.

French cement, is made by melting India-
rubber scraps in a covered iron pot. When
quite liquid, lime previously slaked by ex-
posure to the air and in tine powder, is
added in small quantities at a time. When
moderately thick, it is removed from the
tire, well beaten in a mortar, and moulded
in the hands until of the consistence of
putty. It is useful for mounting large mi-
croscopic preparations &c. A drawn-out
thread of this is pressed upon the top of the
cell ; the object and liquid are then added,
and the cover pressed upon the cement,
beginning at one side, so that the super-
fluous liquid may escape.

A number of other cements, applicable to
various purposes, are described by Beale in
How to Work &c. p. 54. The method of
using these cements is treated of mider
Preservation.

The varnishes should be kept in wide-
mouthed capped bottles, or in bottles accu-
rately closed by a cork, in the imder part of
which a camel's hair pencil is inserted.

A black colour may be imparted to any of
the varnishes, by mixing them with lamp-

black ; or any colour, by adding correspond-
ingly coloured scnxling-wax.

Tiiey should all be old, or kept some time
before use.

CENAN'GIUM, Fries. — A genus of
Phacidiacei (Ascomycetous Fungi) grow-
ing upon dead twigs, bursting through the
bark in the form of little cups or hollow
papilla}. Tulasne has recently made some
interesting observations upon this genus,
and shown that the plants present two or
even three kinds of reproductive bodies,
asci with spores, and also spcrniogonia and
pi/cnidia with sperviatia and sttjlospores. In
C. Cerasi, Yw, the pycnidia are minute
tubular bodies upcin the same stroma as the
young cupules or asciferous cups. They have
been described as species of Sphceria and as
imperfect cupules of C. Cerasi; but their
walls are lined with basidia, producing
short-stalked stylospores, which are linear
and flexuous, and very large, viz. about
1-500' ' long ; they exhibit three transverse
septa. In this species the pycnidia are
found in groups, and sometimes become
confluent. In C. Fra.vini, Tul. (PI. 26.
fig. 17), the pycnidia contain not only stylo-
spores at the base of the cavity, but around
the upper part are found spermatia seated
on branched articulated filaments. These
organs, however, are not regularly co-
existent, but occasionally occur alone in a
pycnidium ; and sometimes the spermatia
occur even in the asciferous cupules. The
asci in the cupules of C. Framjulce line the
bottom of the cups, and are mixed witk
paraphyses; each ascus or theca contains
four spores. Several other species are com-
mon in Britain.

BnjL. Berk. Rooh. Br. Fl. ii. pt. 2, 211 ;
Ann. N. H. vi. 359, 2 ser. vii. 185 ; Tulasne,
Ann. Sc. Nat. 3 ser. xx. 133, pi. 16.

CENOMY'CE. See Cladonia,

CENTROP'AGES, Kj^oyer.— A genus of
Copepodous Entomostraca.

C. typiciis ; brown ; Nortb Sea,

C. hamatus ; marine.

BiBL. Brady, Copepoda {Ray Soc), i,
p. 64.

CEPHALOP'ODA.— An order of Mol-
lusca, containing the Nautilus, the Argonaut,
the Octopus, the Cuttle-fish (Sepia), &c.,
with the fossil Belemnites and Ammonites.
The cartilage of the cuttle-fish is noticed
under Cartilage ; the dorsal plate or se-
piostaire under Shell.

The chromatophores, or cutaneous pig-

CEPHALOSIPHON.

[ 152 ]

CERATAULUS.

A doubtful ge-

ment-cells, and the cutaneous connective
tissue are interestinp: structures.

CEPIIALOS'IPHON
nus of Rotatoria.

C. limnias. On Ceratophylhim.
BiBL. Pritcliard, Infus. p. G70; Hudson,
M. M. Jn. 187o, xiv. n. IGo.

CEPHALOTHAM'NIUM, Stein. — A
genus of Flagellate Infusoria.

Char. Those of Antliophysa, but the
pedicle stiff, hyaline, and homogeneous 5
filaments two.

C. c<espitosa. Pedicle short ; attached to
Cyclops. C. cunealum, pedicle long ; also
on Cyclops.

BiBL. Kent, Inf. p. 272.
CEPHALOT'KICPIUxM, Fr.— A genus
of Dematiei (Ilyphoniycetous Fungi).

C. curtum is an extremely minute plant
growing upon the leaves of Sedges ; with
scattered, short, brown, erect filaments,
bearing somewhat globular heads composed
of tufts of forked or ternate branches, with
one or two short acute brauchlets, slightly
scabrous, bearing smooth spores.

BiBL. Berkeley, A^in. N. H. vi. p. 432,
pi. 12. fig. 13; Corda, Ic. Funy. i. pi. 5.
fiffs. 253-4.

■ CE'PHEUS, Koch.— A genus of Oribatea
(Acarina).

Char. Cephalothorax witli lamellar ap-
pendages ; tectum attached to cephalotho-
rax by its base only ; claws 3, alike.
C. vulyaris. Common near Paris.
BiBL. Nicolet, Oribatea {Monograph^ ;
Murrav, Ec. Eutom. 221 ; Michael, Tr. Mic.
Soe. 1880, 177.

CERAM'BYX, Linn. — A genus of
Pseudotetramerous Longicorn Coleoptera.

C. ( Astynomus') (cdilis (fig. 367). Found
on old timber.

CERAMIA'CE^.— A family of Flori-
deous Algfe. Rose-red or purple sea-weeds,
one freshwater, with a filiform frond, con-
sisting of an articulated, branching filament,
compo.sed of a single string of cells, some-
times coated with a stratum of small cells.
Fructijication: l.favcUcc; berry-like recep-
tacles, with a membranous coat, containing
numerous angular spores; 2. tetrasj)ore^\
attached to the ramuli or more or less im-
mersed in the substance of the branches,
scattered ; 3. unfltcridia, produced in tlie
same situations as the spores. British
genera :

Ptilota. Frond compressed, inarticulate,
disticlious, pectinato-pinnate. Favcllce pe-
dunculate, involucrate.

Microcladia. Frond filiform, inarticulate,
dichotomous. Favcllce sessile, involucrate.
Ceramium. Frond filiform, articulate,
dichotomous; the joints opaque. Favellce
sessile, mostly involucrate. Tetraspores
mostly immersed.

Spyridia. Frond filiform, inarticulate;
tlie branches clothed with minute setiform,
articulated raraelli. Favellce pedunculate,
involucrate. Tetraspores sessile on the
ramelli.

Griffithsia. Frond articulated, dichoto-
mous, or clothed with whorled, dichoto-
mous ramelli, rose-red. Jf/re/te involucrate,
sessile or pedunculate. Tetraspores sessile,
on Avhorled ramelli.

Wrangelia. Frond articulated, pinnate,
Favellce terminal, involucrate, containing
tufts of pear-shaped spores. Tetraspores
sessile, scattered on the ramelli.

Seirospora. Frond articulated. Tetra-
spores arranged in terminal, mouiliforra
strings.

Ccdlithamnion. Frond, at least the
branches and ramidi, articulated, mostly
pinnate. Favellce terminal or lateral, sessile,
withont involucre (except
in C. Turneri). Tetraspores
sessile or pedicellate, scat-
tered.

Chantransia. Fre.-^h-

water ; fronds filamentous,
articulate, branched, cells
in single series ; favellce in
terminal corymbs.

BiBL. Harvey, Man. Jir.
Alqce; Cramer, Ceram.
1863; Sachs, Bot. p. 393.
See also the Genera.

CERAMIUM, Roth.—
A genus of Ceramiacete
(Florideous Algte), contain-
ing a number of species,
mostly growing between
tide-marks, of which C. cili-
atuni is noted as a beautiful
object under a low magTiify-
ing power. The tetraspores
are often only triple, and arranged tetrahe-
drally and not in a row (fig. 114).

BiBL. Harvey, Mar. Alyce, pi. 22 C ;
Phyc. Br. pis. 1.39-41, &c.

CERATAU'LUS, Ehr.— A genus of Dia-
tomacece.

Char. Frusfulos binate or concatenate,
septate; valves turgid, suborbieular or
broadly ovoid, with 2 tubular processes al-
ternating with 2 spines. Marine and fossil.

Ceraroium Des-

longthanipsii.

Fragment of a frond
showing one te-
tiaspoie in situ,
and two emiity
parent-cells.

Magniiled nO dia-
meters.

CERATIDIUM.

[ 153 ]

OERCOMONAS.

C. tiirgidus = Biddulphia furr/ida ; C.
S))v't/iii = UtipodiscHs radiutus ; C. Icevis =
BiddulpJiia h'vis; C. thermalis.

]}iBi.. J-]hreubero-, Ber.. Berl. Ah. 184.3,
270; Kiibeiihorst, Fl. uihj. i. .31o.

CERATIU'IUM. Ehr.— A genus of In-
fusoria, of the famih" Oxytrichina."

Char. Furnished ^\■ith cilia, horns on the
fore part of the body, but neither hooks nor
stylos.

One species, C. cuneatum. Diijardin con-
siders this to have been a mutilated O.vy-
trieha. The appearance of horns arises from
the anterior part of the body being deeply
notched.

BiBL. Ehr. Infiis. ; Dujardin, Inf. 421.
CERA'TILTM. -Agenusof Isariaoei (Hy-
phomycetous Fimgi) containing a generally
diffused British plant, C. hydnoides, wliich
grows on rotten wood as a tuft of white
simple or slightly branched oblong processes,
which produce on their surface sterigmata
(spicules, Berk.), each of which is sur-
mounted by a spore which easily falls off.
The whole plant readily collapses into a
mucilaginous mass. The cellular appear-
ance figured by Greville depends on the
collapsing of the processes.

BiBL. Berk. Hook. Br. Fl. ii. pt. 2. 320 ;
Grev. Crypt. Fl. pi. 168.

CERA'TIUM, Schrank.— A genus of
Cilio-flagellate Infusoria = Feridinia with
horns.

CERATOCLA'DIUM, Corda.— A genus
of Hyphomycetous Fungi ; consisting of a
single species, C. microspermurn (tig. 349),
characterized by the erect, septate horny
threads, clothed with a pallid stratum
bearing simple sporophores (basidia),
terminated by a single staff-shaped
spore.

BiBL. Corda, Prachtfl. pi. 20.

CER'ATODON, Biidel. — A genus of
Pottiaceous Mosses.

C. purpureus, very common on banks and
walls, seta purple-red; C. cylindricus, seta
pale.

BiBL. Wilson, Bryolog. Br. 83 ; Berkeley,
Brit. Moss. 274.

CERATONE'IS, Ehr.— A genus of Dia-
tomacese.

Char. Frustules cymbiform, free, with a
more or less distinct central nodule, the
apices rostriform and produced.

Smith places the British species in other
genera, thus :

C. arcus = Eunot{a arcus; C. closterium
=zNitzschia cl. ; C. fasciola =: Pleurosiyma

fasc; C. gracilis=Ni(zsc}na tcenia; C.lon-
yissima = JS'^i/zscli iu hirostrata.

Rabenhorst admits C. arcus, C. amphioxys,
and C. toxon (Pcrty).

JiiBL. Ehr. Bcr'.d. Berl. Ak. 18;?9, 1840
et seq. ; Kutz. Bacill. and Sp. Aly. ; Smith,
Br. Didt. ; Rabenhorst, F'l. Aly. i. p.. 76 ;
Pertv, Lehcnsf. p. 205.

CERATO'NIA, Linn.— A genus of Le-
guminosae (Flowering Plants). The pods
and seeds or beans of C. siliqua — the Carob-
or Locust-tree of Spain, are used for adul-
terating coffee. PI. 2. tig. 8, a, b, repre-
sent the characteristic tissues of the pod ;
e and d, those of the bean.

CERATOP'TERIS, Bronguiart.— A ge-
nus of Pteridepe (Polypodiaceous Ferns).
Exotic. The inroUed margin of the leaf
simulates an indusium.

C. thalictroides ; tropics (figs. 226-7
thecae, 228-30 spores).

BiBL. Hook, Fit. Si/ii. p. 174.
CERCA'RIA, Miiil.— These organisms
were formerly regarded as constituting a
genus of Infusoria, but are now known to
consist of the larva) or nurses of Trematoda,
as Distoma, &c.

The body is oblong,depressed, cha,ngeab!e ;
the mouth subterminal, armed or unarmed.
Acetabulum subcentral. Tail hliform, sim-
ple, attenuate at the apex, deciduous.

They are found parasitically on the bodj'',
or within the intestines, liver, ovaries, &c.
of Mollusca (Lynmaiis, Planorbis, &c.) ; and
may be obtained by wounding the body in
water.

C.f areata (PI. 51. fig. 32). On Lymnceus
sfaynaJis, in autumn; length 1-12". C. he-
Ucis viciparcs, in the liver of Paludina vivi-
para. C. planorbis, in the ovaries of Pla-
norbis Cornells and maryinatns.

Diesiug describes 12 " species." See
Distoma.

CERCO'MONAS, Duj.~A genus of Fla-
gellate Infusoria.

Char. Free, body rounded, discoidal or ob-
long, sometimes tuberculated, with a va-
riable posterior prolongation in the form of
a tail, which is longer or shorter and more
or less filiform (PI. 30. figs. 22, 23).

Dujardin remarks that the only absolute
difference between ,the Cercomonads and
the Monads consists in the presence of the
posterior prolongation, which is formed by
the substance of the body becoming agglu-
tinated to the slide, and more or less drawn
out so as to form sometimes merely a tuber-
cle, at others an elongated tail, or a filament

CERCOMONAS.

[ 154 ] CERUMINOUS GLANDS.

almost as slender as the auterior Qlament
and susceptible of an oscillating motion;
also that he thinks he has frequently seen
Monads gradually pass into the state of
Cerconionads. See Bono.

Fouud iu infusions, pool-waters, Sec.

C. acuminnta (PL 80. fig. 22). C. cranfii-
cnuda (PI. 30. tig. 23). C. intmtinalis, in
typhoid diarrhoea, cholera; other species,
many doubtful.

Dallinger and Drysdale describe in a
species of Cercomonas {C. ff/picirs, Kent),
fouud in cod-maceratious 2-3 months old, re-
production by transverse fission ; also by con-
jugation— the individuals becoming amoe-
jjoid, fusing together, and forming a smooth
cyst, from which myriads of aluiost imper-
ceptible germs arc subsequently liberated.

BiBL. Duj. Lifiis. 287; Pritchard, Lif.

Fig. 115.

y f

Magnified 20 diametera.
Perpendioular section of Ihe meatus auilitoriiia oytornns. n. Corium;
6, rcte mucosum ; c. cpidi'miis ; tl, ct'iuminous (glands; e, llicir diuts;
/, their terminal orifices; g, hair- follicle ; A, sebaceous follicles; i, fatty
tissue.

49? ; Perty, Z. Kennt. 171 ; Kent, Inf. 2-58 ;
Dallinger and Divsdale, M. 31. J a. 1873,
X. r,3, 245.
CEREUS. See Cactacete.
CERU'MEN.— The so-called 'wax' of
the ear.

Its morphological elements are : — 1. Hairs ;
these exhibit very beautifully the external
layer of epidermic scales. 2. Occasionally,
the Demodex folliculorum. 3. Numerous
epidennic scales, mostly compressed, shrunk,
or so altered as to resemble fibres, but re-
solvable into their original form by warm-
ing with solution of potash and the subse-
quent addition of water ; by this treat-
ment they are frequently rendered brown,
purplish, or almost black. 4. Very nu-
merous cells, filled with pale fatty matter,
of a rounded or elongate, fiattened, or in-e-
gular form ; these are derived
from the sebaceous follicles.
5. Numerous free oil-globules
of the most varied sizes. 6.
Yellow or brown granules,
and aggregations of them,
mostly free, sometimes con-
tained in cells. 7. Various
elements derived from with-
out, as fibres of cotton, linen,
&c. The deafness of old per-
sons usually arises from an
accumulation of indurated
cerumen. See Cebuminous
Glands.

CERU'MINOUS GLANDS.
— The glands which secrete
the ' wax ' of the ear. They
are situated in the tube of
the ear, or the meatus audi-
torius exteruus of anatomists.
They closely resemble the su-
doriparous ducts in appear-
ance, and exist only iu the
cartilaginous portion of the
passage, where they are situ-
ated between the skin and the
cartilage, or the fibrous mass
which occupies its place.
Each consists of a simple
tube coiled at one end, so as
to form a gland (fig. 115 rf),
the other being continued in
the form of a duct (fig. 115 e)
to the surface of the skin,
upon which it opens; occa-
sionally, however, into the
upper part of the hair-follicle.
The glands consist of an ex-

.-//

CERVmiA.

[ 155 ]

CH.ETOGLENA.

tornal coat of connpctive tissue, with scat-
tered, somewhat spindle-shaped nuclei, and
very tine nuclear fibres ; a layer of Hmooth,
longitudinal, ninscnhir fibres, consisting of
sliort fibre-cells with elongated nuclei; and
an inner single layer of epitlielium, com-
posed of polygonal cells, from 1-1800 to
1-1100" in diameter, with roundish nuclei.
These cells contain round or irregularly-
shaped 3'ellowish-brown granules, of very
various sizes, as also globules of oil. The
duct has a coat of connective tissue, and an
epithelial coat, consisting of several layers
of small nucleated cells, not containing fat
or pigment granules.

UERVINTA, Noi-man. — A genus of
marine Copepodous Entomostraca.
C. Bradyi. Oban.

BiBL. Bradv, Copepoda (Hay Soc), i. 85.
CESTODISCUS, Grev.— Fi'ustules disk-
shaped, cii'cular or oval ; valves with radia-
ting granules, and a submarginal circle of ob-
tuse processes unconnected by special radia-
ting lines of dots with the centre. 4 species.
BiBL. Greville, Mic. Trans. 1865, 48 j
18U6, 123.

CE'TER ACH, Willd.— A genus of Ferns,
usually arranged with the Asplenie^,
although there is only a rudimentary iudu-
sium, the place of this being supplied by
scales. C. ajficiiiamm (Asjjlenium Cefe-
rach), the native species, occurs chiefly in
limestone districts.

OETOCHILUS.— A genus of Entomos-
traca (Crustacea), belonging to the order
Copepopa, and famil)' Cetochilida3.

l)istingiushed by the two small styliform
appendages to the head ; the two-branched
inferior antenn.ie, the branches nearly equal;
the unbranched jaw-feet; the six-jointed
thorax, and four-jointed abdomen; and the
last pair of legs being formed like the rest.
Marine. C.septentrionalis-^ bright red; forms
part of the food of the whale and various
fishes; length 1-10",

Bldl. Baird, i?/-/;;. ^«i5o»2os. p. 2.3-3 ; Grob-
ben, Clam's Arh. 1880, 243, iii. {Jn. Mic.
&0C. 18.S1, i. 734).

CETRA'BIA, Ach.— A genus of Lichens :
tribe Cetrarit i.

C/tar. Thallus bright brown, rigid, erect,
or ascending, divided into laciniae, with
shining cortical layer. Apothecia dull or
bright brown. Spermatia cylindrical.

3 British sp. : C. islandiva, the well-known
Iceland Moss ; C.Delisei; and C.aeidcata.

BicL. Nvlander, Sy)i. 298; Leighton,
Lichen-Flora, 1879, 91.

CETRARIR'I. — A tribe of Lichens;
family Lichenacei.

Char. Thallus compressed, fruticulose, or
membranously dilated ; apothecia marginal;
spores 8, small, colourless, simpl(3.

Genera : Cetruria and Plafysnia.

CEUTIIOS'PORA, Fr.— A genus of Me-
lancouiei (Stylosporous Fungi) closely re-
lated to Phoma, one common species of
which (G phacidioidcs) grows on holly-
leaves; another occurs on the Cherry-laurel
(C. Lauri). It is probable that these are
only forms belonging to some Ascomycetous

genus.

C. phacidioides, Grev. 3-5 cells in the
stroma, splitting into 3-5 plain short teeth.

C. Lauri, Sow, Unilocular, splitting into
3-4 acute teeth.

BiBL. Berk. Hook. Br. Fl. ii. pt. 2. p. 283;
Grev. Crypt. Fl. pis. 253, 254.

CILETO'CEROS,Ehr.

-A genus of Dia-

tomaceae.

CJtar. Frustules concatenate ; valves equal,
subcylindrical, mth two processes, one on
each side, which, in the young state, are
very short and tubular, forming very long
horns as the frustules become older ; horns
subsequently converted into very long, thin
and interwoven siliceous filaments. Marine
and fossil.

Somewhat allied to Biddidphia. Raben-
hoist admits 18 species. C. didymus (PI. 50.
fig. 47). Some British.

BiBL. Ehrenb. Ber. d. Berl. A7c. 1844,
198; Kiitzing, Sp. Aly. 138; Brightwell,
3Iicr. Jn. vi. 155 ; Lauder, Mic. Tr. 1804,
75 ; Rabenhovst, FL Aly. i. 321.

CH.ETOCOC'CUS, Ktz.— A doubtful
genus of Algse.

Char. Filaments rigid, short, spiniform,
arising from a cellular substratum.

C. violacevs, radiate, green, becoming
violet on diying, on Hhizoclonium ; C. hyuli-
iius, on Cladfijuhora.

BiBL. Rabenhorst, Flor. Aly. ii. 199.

CIIyETODIS'CUS, Grev.— A genus of
Diatomacepe.

Char. Frustules disk-shaped; valves cir-
cular or oval, with radiating dots and a
submarginal circle of obtuse processes un-
connected by means of special radiating
lines of dots with the centre.

4 speciee.

BiBL. Greville, Mic. Tr. 1865, p. 48;
1806, p. 123.

CILETOGLE'NA, Ehr.— A genus of In-
fusoria, of the family Peridiujea.

Char. Carapace hispid, or studded with

CH^ETOMIUM.

[ 156 ] Cn.ETOPHORACE.5'.

rigid spines ; no transverse furrow ; an eye-
spot present ; organ of motion a flagelliform
filament.

C. Volmcina (PI. 30. fig. 24 a). Oval,
internal substance brownisli-green ; eye-
spot red ; length 1-1100". Aqiiatic. This
appears to be the same as Trachelomonas
Volvocina. See Trachelojioxas.

C. eaudata. Oval, hispid, with a short
tail; internal substance green; eye-spot red;
margin of carapace urceolate and toothed ;
length 1-850" ; aquatic.

BiBL. Ehr. Infiis. ; id. Ber. d. Berl. Ah.
1840, 199 ; Dujardiu, Infus. 239.

CH.ETO'MiUM, Kunze.— A genus of
Perisporiacei (Ascomycetous Fnngi), having
a filamentous mycelium bearing superficial
roundish or ovate conceptacles clothed with
hairs, finally opening above and containing
clavate asci with paraphyses ; sporidia sim-
ple, ovate. The asci in this genus are very
delicate and are readily absorbed, so that
frequently there is not a trace of them, and
the sporidia seem naked. British species :

C. elatmn, Kunze. Conceptacles sub-
ovate, black or brown, more or less crusta-
ceous ; sporidia apiculate at each end.
Greville, Sc. Cnjpt. FL pi. 230. On mould-
ering straw, old matting, &c. Very com-
mon.

C. chartarum, Ehr. Conceptacles sub-
globose, black, surrounded by a bright yel-
low spot ; sporidia roundish. On paper.

C. (jlahnim, B. On damp straw.

BiBL. Hook. Br. Fl. ii. pt. 2. p. 328;
Kunze, 3Ii/tolof/. Heft i. ; Fries, Si/st. My-
col. iii. p. 254, 255.

CH./E'TOMONAS, Ehr.— A genus of In-
fusoria, of the family Cyclidina.

Char. An oral vibratile organ (whether
a fiagelliform filament or riug of cilia is
uncertain) ; movement of animal slow, but
leaping elJ'ected by means of non-vibratile
brittles situated upon the body.

In putrid animal and vegclable infusions;
in di'ad bodies of other organisms — Clos-
teria, &c.

C. globulus (PI. 30. fig. 25«). Nearly
spherical, ash-coloured, setae numerous ;
length 1-2700".

a constricta (PI. 30. fig. 25 h). Oblong,
constricted in the middle, hyaline, setaj two ;
len<?th 1-5400".

BiBL. Ehr. Infvs. p. 248.

CHzbrrOM OKl'Il A, Kiitz. = CoxFERViE
spec. (Rabenhorst, Fl. Ah/, iii. p; 327 ).

CH/ETONO'TUS, Ehr.— A genus of mi-
croscopic aquatic animals, placed by Ehren-

berg among the Rotatoria (Rotifera), and
by Dujardiu with the Infusoria.

Ehreuberg places it in the family Ichthy-
DiXA. Dujardin gives the following cha-
racters :

Body oblong, convex, and furaished with
hairs or scales above ; flat and provided
with very minute vibratile cilia beueath ;
terminated in front by a rounded margin,
near which is a distinct mouth : posteriorly
bifurcate or terminated by two caudiform
processes.

The three or four species are found in
fresh water, amongst aquatic plants. Their
structure requires further investigation.

C'hcetonohis larus (Pi. 31. fig. 24 ). Length
1-710 to 1-220".

Dujardin appends Ichthydium, Ehr., to
this genus.

BiBL. Ehr. Infus. 389; Duj. Inf. 568;
Mecznikow, Sieh. ^- Kdll. Zeitsch. 1865
{Qu. Mic. Jn. 1866, 240).

CILETO'PHORA, Schrank.— A genus
of Chffitophoracefe (Confervoid Algse), cha-
racterized like Draparncddia by setigerous
branched filaments, but differing from the
latter by the filaments being imbedded in a
gelatinous matrix. The ChcpfophortB are
found in fresh water, forming little green
protuberances on stones, sticks, &c., usually
bright gi-een. The zoospores are formed
singly in the joints, and bear four ciha.
True fruit is figured by Berkeley in C. pisi-
fonnis, Gleani)igs of Br. Alg. pi. 1. fig. 1.

The membrane of the filaments is very de-
licate; and the zoospores appear sometimes
to escape by its solution. British species :

C. endivicpfoUa, Ag. Hassall, Alq. pi. 9.
fia-s. 1 , 2 ; Kutz. Tab. Ph/c. iii. pi. 21. fig. 3,
Ulva incrassata, Eng. Bot. 967. Common
in sti'eams.

C. tuberculosa, Hook. Hass. I. c. pi. 9.
7, 8 ; Kiitz. I. c. pis. 19 and 21. Rhmkma
tuberculosa, Eng. Bot. 2366. Boggv pools.

C. elegans, Ag. Hass. I. c. pi. 9. 3, 4 ;
Kiitz. /. c. pi. 20. Stagnant pools; com-
mon.

C. pisiformis, Ag. Hass. /. c. pi. 9. 5, 6 ;
Greville,' Crijpt. t. 150; Kiitz. /. c. pi. 18;
Thuret, A)in. So. Xat. 3 ser. xiv. pi. 19.
figs. 1-3. Subalpine lakes.

C. dilatatn, Hass. l. c. pi. 13. fig. 2.

C. lonf/ceva, Carm. A doubtful species.
Hook. Br. Fl.u. pt. 1.

Rabenhorst admits 10 species : Fl. Alg.
iii. 383.

BinL. As above.

CILETOPHORA'CE^.— A family of

CH/ETOPSIS.

[ 157 ]

CHALAZA.

Confervoid Algae, growing in sea or fresh
water, rarely terrestrial, invested with gela-
tine ; either tilii'orm, or (a number of tila-
ments being connected together) expanded
into gelatinous, branched, delinitely-foruied
or shapeless masses or fronds. Filaments
jointed, famished with bristle-like processes.
Fructification consisting of spores ; and four-
ciliated zoospores, formed out of the con-
tents of the articulations.

Si/?702)sis of British Genera.

Draparnaldia. Filaments free, gelati-
nous, the primary nearly colourless, bearing
tufts of coloured ramuli at the joint ; zoo-
spores formed singly in the joints of the
ramuli.

Chcptophora. I'ilaments dichotomously
branched, aggregated into shapeless, in-
crusting or branched, gelatinous fronds, the
joints bearing bristle-like branches; zoo-
spores solitary in the articulations ; the
membranes of the filaments very fugacious.

Coleochccte. Frond disk-shaped or ir-
regularly expanded, adherent to leaves &c.
of aquatic plants under water, formed of
jointed dichotomous filaments radiating
from a centre, more or less conjoined late-
rally; the joints producing from the back a
slender truncate open tube, from which a
long bristle is exserted. Fructification :
spores and zoospores formed in the joints.

OcMochcBfe. Frond discoid, appressed ;
filaments cylindrical, radiating from a centre,
irregularly branched, consisting of a single
series of cells, each of which is commonly
prolonged above into an articulate bristle.

Foreign genus. See Aphanoch-s;te,
Kiitz.

BiBL. See the genera.

CH.FTOP'SIS, Grev.— A gemis of Mu-
cedines (Hyphomycetous Fungi) charac-
terized by erect jointed threads, whorled
below, above simple and flagelliform, bear-
ing cylindrical spores from the tips of the
branclilets. One species only is known, C.
Wauchii.

BiBL. Grev. Crypt. Fl. pi. 23G ; Berkeley,
Br. Fung. .35.3 ; Cooke, Handbook, 614.

CH.ETOSPI'RA, Lachmann.— A genus
of Infusoria, of the family Bursarina.

Char. Buccal spire supported on a nan-ow
band-like process, at the base of which is
the mouth.

C. Miilleri. Shell lageniform, horny. On
torn leaves oiLemna trisulca.

C. mucicola. Shell gelatinous. Among
Algae, fresh water.

BiBL. Ann. N. 11. 1857, xix. pi. 9. figs. 6
and 7 ; Claparede and Lachmann, Inftts. 216 ;
Kent, Infus. 601.

CH^TOSTllO'MA, Corda. See Volu-

TELLA.

CH^TOTYPH'LA, Ehr.— A genus of
Infusoria, of the family PeridinEea.

Char. Carapace (siliceous P ) hispid or
covered with rigid hairs ; no transverse
furrow, no eye-spot.

C. armata (PL .30. fig. 26 : a, side-view ;
h, posterior end view). Ovato-subglobose,
rounded at each end, hispid with short
setae, posteriorly a ring of dark prickles ;
length 1-0:20".

C. aspera (PI. 30. fig. 26 c). Oblong,
rounded at each end, hispid with short setse ;
posterior prickles scattered without order ;
length 1-550".

C. ? pyritce. Oblong cyliudiical, ends
rounded ; sette slender and elongate ; no
posterior prickles ; length 1-llOU", breadth
half the length. Fossil in flint. Ehreuberg
questions whether this is not a Xanthidium.
BiBL. Ehr. Infus. 250; Duj. Inf. 328.
CHAITOPH'ORUS, Koch.— a genus of
Aphidse.

Char. Antennae hirsute, 7-jointed; upper
wings with a doubly forked cubitus ; lower
with two oblique veins; abdomen studded
with tubercles tufted with bristles : dimor-
phous.

Several species ; occurring upon the wil-
low, poplar, birch, &c.

BiBL. Buckton, Aphides {Hay Sac), ii.
120.

CHA'LARA. — A genus of Mucedines
(Hyphomycetous Fungi) ; characterized by
the erect jointed threads, which at their
slender apices break up into cylindrical
spores.

C. longipes has been found in this countiy.
BiBL. Sturm, D. Fl. 29, pi. 35 ; Saccardo,
Fasc. i. pis. 29-35.

CHALA'ZA (in plants). — The teim ap-
plied to the base of the nucleus of ovules,

Fis-. 116.

Ch^

r_U-,

Section of an anatropons ovule : /", fimiculns : r,
raphe; ch, chalaza; p, external coat of testa ; s, inter-
nal coat or tegnjen ; n, nucleus.

where the substance of the former is con-

CHALCIDID.E.

[ 158 ]

CHALCIDID.E.

tinuoiis with the coats, and where the vas-
cular cord derived from the placenta termi-
nates (tig. IK), ch).

CHALCID'ID^.— A family of Eutomo-
phagous Tert'brant Ilvmenoptera, distin-
guished by the following characters : —

Head transverse, with the eyes lateral
and the face usually bisulcate for the re-
ception of the base of the anteimje (PL 36.
fig. 8). Antennfe short, frequently thick-
ened at the tips, sometimes branched, com-
posed of not more than thirteen joints,
and almost always geniculated at the ex-
tremity of the elongated first joint. Palpi
veiy short, sometimes branched. Thorax
ovate, with a distinct collar. A\" iugs nearly
destitute of veins ; the anterior with a rather
strong subcostal vein running parallel to the
anterior margin for about half the length of
the wing, and terminating in a stigma, from
which a short vein is given ofl' obliqiielv
towards the disk of the wing ; the posleritir
sometimes veinless, sometimes with a short
subcostal vein. Ijegs moderate ; hinder
thighs sometimes much thickened ; tarsi of
four or five joints. Abdomen generally com-
posed of seven segiuents in the males and of
six in the females, united to the thorax by
a peduncle of variable length ; ovipositor
usually concealed entirely in a cleft of the
lower surface of the abdomen, which ex-
tends nearly to the base (tig. 9), but some-
times exserted and very long. The struc-
ture of the ovipositor is the same as that of
the Ichnei(?)tO)iid(B.

The larvte, like those of the rest of the
petiolated Hymenoptera, are footless fleshy
gi-ubs (flg. 10). Like the larvse of the Ichneu-
monida?, they usually live in the interior of
other insects; but it is remarkable that those
of a few species attach themselves to the
skin of their victim, and in this position
feed upon its substance. The internal
feeders generally change to the pupa state
within the pupa of the insect attacked by
them ; a few, however, break through the
skin of the larva and attach themselves to it
or to neighbouring objects by a glutinous
secretion, or by a small silken cocoon. The
pupje have the limbs more closely attached
to the body than in the other Hymenoptera;
and in those which have an elongated ovi-
positor, that organ is turned up over the
back. The pupa; are at first whitish, but
afterwards become brown or black ; they
are usually naked (fig. 11).

The family Chalcididaj includes an im-
mense number of parasitic Hymenoptera,

the majority of which are of extremely mi-
nute size, and adorned with the most" bril-
liant metallic colours. This circumstance,
coupled with the delicacy of their form,
renders mauy of the species most beautiful
objects ; and considering their interesting
habits, they certainly do not deserve the
almost total neglect which they have met
with. The largest species belong to the
genus Leucopsis ; but none of these greatly
exceed half an inch in length, and they are
not found further north "than the South
of Europe. The thickened hinder thighs
which occur in many species of this fa-
mily, do not always indicate that the in-
sects possessing tliem are endowed with
saltatorial powers ; on the other hand, many
species which are destitute of thickened
thighs leap well ; and according to West-
wood's observations, this is especially the
case with those in which the intermediate
tibic-e are furnished with a large spine at
the extremity {Encyrti's, PL 36. fio-. 12).

The perfect insects may be met with in
abundance duiing the summer and autumn
iipon the leaves of trees and plants. They
may be taken either by sweeping the herb-
age with a net, or by beating trees or hedges
over a broad net or umbrella.

The sexes are olten distinguished in this
family by remarkable external characters,
especially in the structure of the auteume.
These, in the males of many species, are
beautifully branched, in consequence of the
joints giving oft" processes from their sides ;
in Eiduphus (fig. 13) we usually find three
branches ; and in some foreign genera re-
corded by Westwood the number is in-
creased to five, seven, and even nine. A
few species have the wings rudimentary or
entirely wanting; and it is remarkable "that
in some cases the male only is deprived of
wings, the female being well furnished with
these organs.

The Chalcididoe are parasitic upon insects
of nearly all orders, and deposit their eggs
in them in all stages of their growth. Some
of the minute s]ircies even" find sutficieut
nourishment in tlie eggs of other insects ;
amongst these we may mention Pteromalus
ovulorum as a common species, which has
been reai'ed from the eggs of Lepidojjterous
insects. From a single ^go^ of this descrip-
tion, Fouscolombe obtained five or six indi-
viduals of a mmute species, described by
him under the name of Pteromalvs atomo's.
\A'estwot)d also m(>ntions the occurrence of
two species of this family in the egg-cases

CHALCIDID^E.

[ 159 ]

CHALK.

of species of Mantis from Brazil and the Me
of I'raiioe ; aud Sells has recorded the oc-
currence of uo less lliau ninety-four speci-
mens of a small Pleromulus in a single egg-
case of a Blatta.

Other minute species deposit their eggs
in the bodies of Aphides ; aud their larvie
tind a 8utKeient supply of nourishment even
iu such small insects as these. Some,
especially those forming the genus Cocco-
2)Jio(/us of Westwood, attack the Coccidcc,
of which they destroy great numbers.

Other species, including most of the larger
forms, live parasitically in the cells of the
solitary Bees and Wasps. Amongst these
-we may notice the singular genus Mono-
dontomerus, one species of which, first
discovered by Audouin, and described by
Newport iu the ' Linnean Transactions,' is
found in the nests of Odynerus, AnfJiop/tora,
aud Osmia. The male of this remarkable
insect has only rudimentary wings, so that
it is unable to quit the cell of the Bee or
"Wasp in whicli it passed its earlier stages,
w'hilst the female, being well provided with
wings, can fly about, after impregnation, to
seek other nests iu which to deposit her eggs.
The species which are furnished with long
ovipositors belong chietly to the genus t'al-
limome (tig. 14, C. cynipis) ; they deposit
their eggs in different kinds of galls, the
vegetable excrescences caused by the punc-
tures of various other insects upon plants.
The larvfe of these gallicclous ChacididcO
devovu" the rightful occupant of the gaU.

The instinct which prompts these insects
to deposit their eggs in the larvai of these
gall-producing insects, is scarcely so asto-
nishing as that by which others are impelled
to insert theirs into the bodies of other para-
sitic insects, whilst still enclosed within
the tissues of their victim. Some of these,
such as Viirysolaminis si(spc7isus and C'oruna
claiata, attack the larvie of the Apltidii,
minute Ichneumons which infest the bodies
of Aphides ; and De Fili[ipi has recorded
the occurrence of the larvte of one species
within a small Dipterous larva which itself
lives in the (^^^ vi lihyniliites Betuleti in
the vineyards near Turin (^Ann. N. H. 1852,
ix. 4(jl). l>e Filippi is inclined to regard
the phenomena observed by him as an in-
stance of alternation of generations; but
they evidently constitute an example of
double parasitism.

BiBL. Westwood, Introd. ii. & Zod. Jn. ;
Spinola, Ann. 3Iiiseum, xvii. 138-152 ; Nees
von Eseubeck, Jlynenopt. Ichncum. Man.

ii. ; Boyer de Fonscolombe, Mon. Chalc.
Gallo-l'rovincifB, Ann. Sci. Nat. xxvi. ;
Walker, Man. Chalcid.; Dalman and Bohe-
man in Koixjl. Vet. Alutd. JIandlinyar ;
Walker, Entum. May. and Ann. N. H. ;
Gueriu's May. de ZouL, Ent. May. &c., and
Haliday, Enfom. Mag.

CllA'LIMUS, Burm.— A genus of Crus-
tacea, of the order Siphonostoma, and fa-
mily Caligndse.

Char. Fourth pair of legs slender, of only
one branch, and serving for walking ; frontal
plate with a long aud slender prehensile
appendage arising from the middle of its
anterior surface.

C scombri. Found upon the mackerel,
and upon species of Caliyus, of which it has
been supposed to be the young ; length
about 1-U".

BiBL. Burmeister, N.A.Acad. N. C. Bonn,
xvii. ; Baird, Brit. Entomostr. p. 278.

CHALK. — An eartliy form of carbonate
of lime, constituting strata of great thick-
ness in England and several parts of Europe,
&c. The application of the microscope to
the examination of chalk brought to hght
the interesting fact that this substance has
not had its origin in chemical precipitation,
since it contains abundance of the inorganic
remains ( if marine animals, and a few plants,
perhaps doubtful.

Many of these relics are not microscopic,
as those of Fishes and Reptiles, the shells of
Malacostracous Crustacea, Mollusca, Echi-
nodermata, the polypidoms of Zoophytes,
&c. ; hence their consideration does not
come within our province : yet it must be
remembered that their microscopic structiire
is characteristic, so that the class, order, or
even the more minute division of the ani-
mal kingdom to which they belong may be
discovered. See Bone and Shf.ll.

The chief microscopic constituents of the
calcareous formations examined by Ehren-
berg, viz. chalk, and uummulitic and other
compact limestones, were found to be
shells of Foraminifera, spicules of sponges,
and peculiar bodies called crystalloids ; and
several siliceo-calcareous earths he found
to be wholly composed of s]iicules, Diato-
maceje, I'olycystina, and Foraminifera.

The F( raminifera found by Ehrenberg
in the Grave.-end chalk were: — Cristellaria
ctdtrata, Glohiyerina cretacca, Ilelerosto-
niella acrdeata aud tiinums, Nodvsaria ovi-
cnla, Flanorhidina ammunoides, Polymor-
phina TJivimti, Pulvinidina Micheliniana,
Textularia ayylutinans, yiilosa, ylolulosa,

CHALK.

[ 160

CHAM.ESIPHON.

striata, and subangulata, Vagimdina laevigata
and loTiga, VerneuUina spinuhsa, and l~ul-
vidiua pennatida. D'Oibigny enumerated
22 species from the English chalk, including
some of the above ; many others have also
been found.

The genera and subgenera in which they
are grouped are — Bolwina, Bulimina, Cal-
CARiNA, CristeJlaria, DentaUna, Flahellina,
Frondicularia, Gaiidnjhui, Globigerina,
IIaplophragmu(m,IIeterostomcUa,Lingulma,
IjAGKNA, Lituola, Marginidina, Miliola,
Kodosan'a, Xodosarina, Plamdaria, Pla-
indina, Planorbulina, Polymorphina,
PuLviNULiXA, Qiiinqueloctiliiia, llamulina,
RoTALTA, Sagrina, Sph^eroidina, Tex-
TULARiA, TiNOPORUS, Tvitaxia, Teocham-
MiNA, Truncatidlna, Valvulina, J\'nuiu-
lina, Virgtdina, and Wchhina.

Ehrenberg found two Diatoraaceaj in the
English chalk, viz. Fragdaria capttcina i^F.
rhabdoso7na), and Fr. jnnnata, Ehr. (=:i^.
mutabdis, Sm.). Some other Diatomacese
referred by Ehrenberg to the chalk, belong
to foreign chalk and to totally different beds.

The material of chalk comprises very
minute, numerous, and remarkable bodies,
called crystalloids and morpholites byEhren-
berg (PI. 25. hg. 15). They are elliptical
or rounded, and flattened, from 1-10,000 to
1-25C0" in length, the most numerous per-
haps 1-3000"; some of them consist of a
simple ring (a) ; in others this is marked
•with pretty regular trans-^erse lines, so as to
make it appear jointed (h) ; in others, again,
there is a thinner central portion, often ex-
hibiting one or more granules (c). Ehren-
berg regarded these as arising from the dis-
integration of the microscopic organisms
forming the chalk into much more minute
calcareous particles, and their reunion into
regular elliptical plates or disks by a pecu-
liar process, diffei'ing essentially from, and
coarser than that of crystallization, but
comparable with it, — one probably preceding
all sicno crystalline formation, and causing,
but not alone, the granular state of solid
inorganic matter. These microscopic bodies
have of late years been regarded as the
agglomerated or separate plates of very
simple protozoan organi.sms by Huxley,
Wallich, and Sorby. By Carter they are
believed to belong to an Alga (Cocco-

LITHS).

The best method of examining chalk for
minute Foraminifera is this: place a drop
of water upon a glass slide, and put into it
as much iiuely sci-aped chalk as will cover

the point of a pen-knife ; then diffuse it
through the water, and set it aside for a few
seconds. Next remove the finest particles
which are suspended in the water, together
with most of the water, and allow the re-
mainder to become perfectly dry. Moisten
this remainder yv\t\\ oil of turpentine, and
warm it over a spirit-lamp ; then add Ca-
nada balsam, and digest it upon the brass
table (Intr. xxviii), but without its froth-
ing." A preparation thus made seldom fails ;
and when magnified 300 diameters, the mass
is seen to be chiefly composed of minute
well-preserved organisms. As thus pre-
pared, the cells of the Foraminifera first
appear black, with a white central spot
(PI. 24. fig. 3), which is caused by air-
bubbles contained within the cells. The
balsam gradually penetrates into the cells,
the black rings of the air-bubbles disappear,
and the minute, frequently very elegant
cells of the Foraminifera become visible.
See Flint, and For.\minifera.

The crystalloids are best examined in
common whiting, or powdered chalk, which
has been shaken with water and set aside.
A very minute quantity removed with a
dipping tube will exhibit them.

BiBL. The various works on geology, as
those of Lyell and Ansted ; Mantell, Won-
ders, Medals of Creation, and Ann. N. H.
1845, xvi. p. 73 ; Bowerbank, Geol. Tr. 2 s.
vi. ; Ehrenberg, Ahh. d. Berlin. Ak. 1 838
{Ann. N. II. 1841, vii.), and Ahh. d. Berl.
Ak. 1840 (Taylor's Sc. Mem. iii.), and 3Ii-
krogeologic, 1854 ; Parker and Jones's Ehr.
resume, Ann. N. II. 1872 ; "Williamson,
Manchester Lit. Phil. Soc. viii. 1847 ; Mor-
ris, Cat. Br. Fossils, 1854 ; D'Orbignv,
Mem. Soc. Geol. d. France, iv. (Abs., Ann.
N. H. 1841, vii. p.3U0) ; Zirkel, Mineralien
4-C..1873, .303 5 IJixou's /S'i^ssc.r, 2 ed., 1878,
123 & 283.

CHALK-STONES. This term is vul-
garW applied to the white concretions
formed around the joints in chronic gout,
or, as it is sometimes called, rheumatic gout.
They consist of very minute needles of urate
of soda (PI. 12. Iig.l2i).

CIIAM/ENE'iNfA, Kiitz. — A supposed
genus of Leptotricheous Algae, consisting of
dusky-coloured jointed filaments, forming
flocks in various syrups. Doubtless the my-
celia of some Fungi, such as Penicillium.

BiBL. Kiitzing, Sp. Alq. 158.

CHAM.*]'SIPHO\, B'raun.— A genus of
Oscillatoriacere (Confervoid Alga3).

Char. Trichomata erect, asruginous or

CIIANTRANSIA.

[ 101 ]

CITARACE^E.

violet, parasitic, sheatlied, articulate ; ter-
minal joints Ibrmiug roLiuded gonidia. I'^our
species.

C. confervicola (PI. 3. fig. 6). On Calo-
tJirix, Vaucherio, Sec.

BiBL. Kabonliorst, Fl. Alg. ii. 148 (tigs.).
CHANTRAN'SIA, Fries. — A genus
of Ceraniiacefe (Florideous Algas).

Species numerous, purple, violet, or ferru-
ginous. Found on stones, submerged mosses,
and -wood. Antlieridia subglobose, terminal,
tetraspores rare.

liiBL. Rabeuliorst, Fl. Alg. iii. 401 ;
Priiigslieim, Beit. z. Morph. d. Meeres-
Al(/en ; Ilassall, Alff. 75.

CIIA'RA, L. See Chaeace^^e.
CHARA'CE.-E.— A femily of plants ge-
nerally classed among the Algte, but which,
fi-om the character of their reproductive
organs, perhaps demand a more elevated
position. They may be placed on the boun-
dary between the Algfe and the Ilepaticje.
They are remarkable for their well-known
' circulation,' first discovered by Corti. The
Characege are aquatic plants, of filamentous
structure, exhibiting elongated axes fur-
nished at intervals with whorls of branches
(fig. 117) ; these are sometimes regarded as
leaves. In some species this axis is a
simple tube (fig. 124), sometimes a tube
with a cortical layer of smaller tubes sur-
rounding it (figs. 118, 119). Some authors
have divided the species, on this and some
other grounds, into two genera, Nitella
(simple tubes) &\\AChara (corticated tubes) ;
but according to Al. Braun, who has de-
voted great attention to this family, the
characters will not hold. The mode of
ramification of the simple tubes is seen in
figs. 124 & 125 ; that of the compound axes
is fundamentally the same, but other cells
arise from the branch cells at the articula-
tions, one above and one below each branch
(C. crinita). Those on the upper side of
the branches gTOw up over the central axis
to meet those descending from the under
side of the branches of the whorl next
above, the ends becoming intercalated about
the middle of the internode : in this course
of growth, cell-division takes place, and the
primary cortical tubes are not only made up
of many lengths in each internode, but each
is perpendicularly divided into two, one
large and one smaller tube (C vulgaris), or
produces a secondary tube on each side {€.
aspera) ; the primary tubes stand out as ribs
from the surface. These cortical tubes de-
scribe a spiral course around the internode.

Fig. 117.

Fig. 118.

Fig. 120.

Fig. 119.

Fig. 117. Chara vulgaris. Natural size.
Fig. 118. Fragment of stem, magnified 15 diam., show-
ing the cortical tubes.

Fig. 119. A section of ditto, magnified 30 diam.
Fig. 120. Branch with nucule and globule, 10 d'f.m.

Filamentous radical cells are also produced
from the whorls. The cells of the main
axis and its branches, and the primaiy cor-
tical cells, are those in which the circula-
tion of the contents may be seen best. The
cell-wall is liced by a close layer, like a

ii

CHARACEvE.

[ 162 ]

CHARACE^.

pavement, of cliloropliyll-globules imbedded
in colourless protoplasm, arranged in a some-
what spiral order ; within them lies a thick
layer of semigelatinous consistence (the
circulating protoplasm) ; and the centre is
filled up with a watery liquid. The circula-
tion in the ordinary cells consists in the
movement of the gelatinous protoplasmic
sac, as one mass, slowly up one side of the
cell, across the ends, and doAvn the other
side, — not perpendicularly, however, but in
an oblique or spiral course, as indicated in
fig. 125. The fiuid in the centre does not
circulate, but contains vesicles, granules, or
other bodies floating in it, whicli are free,
and when resting upon tlie protoplasmic
sac, are carried along by it and up the side
of the cell, until they fall down again by
gravitation. The young cells from which
the fruits are developed exhibit a circula-
tion of green vesicles; the cortical filaments
have acirculating primordial utricle without
chlorophyll-globules.

The circulation is obscured in many Charce
by the existence of an incrustation of the
cell-wall hj carbonate of lime, often found
in rhomboidal crystals. In C. (NiteUa)
tra7islucens, Jiexilis, and other species, this
does not exist ; and these species without
cortical tubes exhibit the phenomenon more
clearly than the others. Those species,
however, which are subject to incrustation
have comparatively little about the tips of
the shoots ; and if they are kept growing
for some time in a jar of water pretty free
from lime, new shoots maybe obtained very
suitable for examination. When we care-
fully examine the conical terminal cell of a
shoot, we find the following characters : —
The cell-membrane is distinctly laminated,
and thickened at the conical apex of the
cell ; when sulphuric acid and iodine are
applied, the cell-wall exhibits a thick in-
ternal layer of a blue colour, indicating its
composition of cellulose, while a thin layer
extending all over the outside becomes
bright yellow, and thus presents a resem-
blance to the cuticular layer of the higher
plants. The cell-wall is lined by a thin
layer of protoplasm, in which are in:bedded
a vast number of chlorophyll-globules,
closely set and arranged spirally, as above
stated. ; a clear line extends obliquely up in
this layer, bare of chlorophjdl. The chloro-
pliyll-globules have much the appearance
of vesicles here, and contain starch- cor-
puscles, which cause the whole layer to
turn blue with iodine. (See Culoro-

Fig. 121.

Fig. 124.

Pig. 121. A globule, magnified 50 diam., showing the
triangular valves.

Fig. 122. A globule cut in half, to show the oblong
cells and the septate filaments in the centre, 50 diam.

Fig. 123. Portion of a sejitate filament, 200 diam. ;
with two bieiliated spermatozoids, 400 diam.

Fig. 121. Chara transhicens, showing its simple tubes
and nucules grouped in threes under the terminal
globule.

Fig. 125. Diagram representing the course of the cir-
culation in the main tube and branches of Chara.

riiYLL.) Within this motionless layer is
found the thick rotating layer of protoplasm,
in which again are imbedded numerous
starch and chlorophyll-globides, a vast num-
ber of minute granules, and a number of
globular bodies of larger size, 1-1500", ac-
cording to Goppert and Cohn covered with
rigid cilia. The internal boundary of this

CHARACE-E.

[ 163 ]

CHEESE-MITE.

layer is wavy and irregular ; and thus its
rotation carries along, to a certain extent,
the watery juice tilling up the centre of the
cell, in which lie numerous transparent pro-
toplasm-vesicles, ciliated bodies, and gra-
nular matters.

Thefructiticationof Chara is very curious,
and its homologies are not yet satisfactorily
made out. Upon the branches are found
bodies of two kinds, either on the same or
on different branches, or on different plants ;
called the glohde and the nucule. The glo-
huJe (figs. 120, 121) or antheridium is a
spherical body, of a red or orange-colour
when ripe, presenting a transparent thickish
outer coat, enclosing an inner wall of curi-
ous construction. This is composed of
eight triangular plates, each composed of a
numberof long wedge-shaped cells radiating
fi'om a central cell. The plates have dentate
margins, by which they fit into one anotlier
(fig. 121). The cells contain a red colour-
ing-matter. In the centre of each plate,
inside, rises an oblong cell running in to-
ward the centre of the globule, where it
meets its fellows from the other plates, and
they are united by a little collection of sphe-
rical cells ; a ninth cell, of similar form but
larger size, comes to join these in the centre,
it being the pedicle of the globule, arising
from the branch upon which it is seated,
and enterino: the Eflobule between the lower
four valves. At the point where these nine
cells meet in the centre, a number of long
septate filaments arise (fig. 122). These are
composed, when mature, of a large number
of cells placed end to end (figs. 122 & 123),
each of which finally discharges a ciliated
spiral filament (spermatozoid), which swims
actively in the water. The globule bursts,
by the separation of its triangular valves,
when mature ; and it is after this that the
spermatozoids are emitted. The form of
these spermatozoids is very like that of those
found in the Mosses, and different from what
is seen in the Fems, Lycopodiacese, &c.
(PI. 40. figs. .31-34).

The nucule or carpogon of the Chares
(figs. 120 & 124) forms an oval body coated
by five cells, wound spirally around a central
tough sac; the five cells terminating above
in five or ten smaller cells, which proj ^ct like
teeth from the summit, forming a kind of
crown. The cells of the crown separate from
each other at a particular period, leaving a
canal leading down to the central cell, which
contains protoplasm, oil, and starch-glo-
bules. Ultimately the nucide falls off, fcn-ms

a resting-spore, which germinates, and be-
comes developed into a new plant. The
germinating spore does not, however, di-
rectly give origin to the young plant ; but,
as in the higher Cryptogamia, a prothallus
is first formed, and upon this, the first
branches of the plant arise by ordinary
gemmation. The prothallus consists of a
single row of cells, forming a filament. This
is not produced, however, in Kifella.

The CharcB also multiply by gemmse,
produced at the articulations of the stem ;
of which there are three modifications.

Carter has published some interesting
observations on the development of the root-
cells of Chara ; also an account of the ab-
normal products which are sometimes found
in decaying cells.

BiBL. Corti, Osserv. sulla Circulazione,
1774; Amici, Mem.d. Societa itaUana,\SlS;
Ann. d. Sc. N. 1824 ; Dutrochet, Ann. cl. Sc.
Nat. ser. 2. x. 349; Meyen, I'Jianzen-jjhys.
ii. 206 ; Varlev, Tr. 8oc. Arts, xlix. 1633 ;
Micr. Tr. ii. 93, 1849 ; Slack, Tr. Soc. Arts,
xlix. ; Thuret, Ann. d. Sc. Nat. 2 ser. xiv,
65, 3 ser. xvi. 18 ; Treviranus, Phys. d.
Gewcichse, i. 1839 ; Kiitzing, I'hyc. qen. 313 ;
C. Miiller, Bot. Zeit. 1845 {Ann. N. H. xrii.
254) ; Goppert and Cohn, Bot. Zeit. vii. 665,
1849 ; Bvh\m,Ber. Berl. Ak. 1852-3 (Ann.
N. H. 2 ser. xii. 297) ; Carter, Aym. N. H.
2 ser. xvi. 1, xix. 13; Pringsheim, Jahrb.
1864; Berk. Suppl. Enxj. Bot. t. 2762;
Nageli, Beit. ii. 1860 ; De Bary, 3fonatsb.
Berl. Ak. 1871 ; Sachs, Bot. 29o.

CHARA'CIUM, Braun. — A genus of
Confervoid unicellular Algae, of doubtful
position ; reproduction by repeated binary
division of the eudochrome. Allied to Ifi/-
drocytimn. Adherent to larger submerged
Algae. Perhaps only male spores of CEdo-
gonium and allied genera.

Kabenhorst describes 13 species.

C. Siebokm (PI. 5. fig. 2). On filiform
Algae and freshwater mosses.

BiBL. Tlabenhorst,i'7.^i(r/. iii. 82; Braun,
Ah/. Umcell. Gen. nova, 1855.

CHASMATOS'TOMA, Engehnann.— A
genus of Holotrichous Infusoria.

Char. Free, ovate or reniform ; cilia long,
matted ; mouth near the centre of the flat-
tened ventral surface, enclosing a minute
undulating membrane.

C. reniforme. Fresh water ; length -^\ -'.

BiBL. Engelmann, Zeitsch. wiss. Zool.
1802, u. ; Kent, Lif. 540.

CHEESE-MITE. See Ac.vrxjs domes-

TICUS.

M 2

CHEESE-MOULD.

[ 164 ]

CHELIFEE.

CHEESE-MOULD. See AsPERGiLLrs.

CHEILAN'THES, S\v. — A geuus of
Pteridi'se (Polypodiaceous Ferns), nearly
related to Adkintum. The marginal lobed
indusium is very narrow ; some species have
the under surface of the leaves mealy, from
the presence of microscopic hairs.

A large geuus ; tropical.

BiBL. Hooker, Siin. Fil. 131.

CHEILO'SCITHUS, Corda.— A genus
of Jungermannieae (Hepaticae), founded
Vi^ow Jung ennannia jjohjanthus, L.,v?hich is
not unfrequent in wet places.

BiBL. Hooker, Brit. Junxjerm. pi. 62 ;
Corda, in Sturm, Deutschl. Fl. ii. 19, 20,
p. 35, pi. 9.

CHEILOSTO'MATA. — A suborder of
lufundibulate Polyzoa (marine).

Char. Oritice of cell hlled with a thin
membranous or calcareous plate, with a
curved mouth, furnished with a moveable

lip-

It is divided into two sections, contaming

numerous families and genera.

Tribe 1. Articulata. Polyzoarium jointed.
Salicornahiidje. Polyzoarium erect,-
cylindrical, dichotomously branched ; cells
arranged on all sides.

CELLAKnD^.

CELLULARHDiE. Polvzoarium erect,
branches fiat, linear, ceUs in the same
plane.

Tiibe 2. Inarticulata. Polyzoarium un-
jointed.

EtJCRATiiD^ (Scrupaiiidaj). Cells in one
row. Aeteid^e.

Gemellariid^. Cells in pairs opposite.

Cabereid^. Branches narrow ; cells in
two or more rows, with whips or sessile
birds' heads at the back,

BiCELLARiiD.E. As the last, but whips
absent, and birds' heads stallied and jointed.

Flustrid^e. Zoaiium expanded, folia-
ceous, and flexible.

Membraxiporid^. Expanded, incrus-
ting, stony ; cells horizontal, quincuncial.

MlCROPORID^E.

Celleporid-e. Massive, globose, in-
crusting, or erect, stony; cells vertical to
the common plane, irregidarly heaped toge-
ther.

EscHARiD.E. Expanded and leafy, or
branching, stony ; cells in tlie same plane,
quincuncial.

Cribru.inid.e, Micropoeellid.e,

MyRIOZOIDiE.

A genus

of

PoRixiD-E. Poh'zoarium incrusting, or
erect and branched ; cells with a raised
tubular or subtubular oritice, and frequently
a special pore on the front walls.

BiBL. Johnston, Br. Zooph. ; Busk, Cat.
Mar. Polyz. {Brit. 3Ius.); Gosse, 3Iar. Zool.
i. ; Hincks, Polyzoa, 1.

CHEtROCEPH'ALUS. See Braxchi-

PUS.

CHEIROS'PORA, Fries
Melanconiei (Stylosporous Fungi
upon the twigs of the beech. The myce-
lium spreads under the epidermis, and bursts
through in rounded or irregular, conical,
black pustules, 1-20" in diameter, which are
composed of a large number of fine filaments,
unequal in length, and waved, each termi-
nating in a bunch of spores. The heads are
formed of chains of spores like a Penici/liiim,
when young, but crowded togetlier more
densely as they become more fully developed
into a globular or oval head, about 1-700";
the spores about 1-400U". This genus cor-
responds to Stilhospora, Montague, 3l//rio-
cephalum, De Notaris, and, ajiparently,
Hyperomyxa, Corda ; but the latter is said
to have a mucous vesicle enclosing the
head.

C. hotryospora, Fr. On dead beech twigs,
Berk, and Broome, Ann. N. H. 2 ser. v.
455. Fresenius finds a variety on the horn-
beam.

BiBL. Cheirospora, Fries, Sinnma Veyet.
508 ; StilbosjMr.a, Fries, Syst. Mycoluy. iii.
448 ; Montague, Ann. Sc. Kat. 2 ser. vi.
338, pi. 18. fig. 5; Hyperomyxa, Corda,
Ic. Funy. iii. fig. 78 ; Montague, Ann. Sc.
Kat. 2 ser. xx. 378 ; Myriocephalum, De
Notaris, Mem. Accad. Torino, ser. 2. vii. ; .
Fresenius, Mykuloyie, 39, pi. o. ^"^)^, 1-9
(2tes Heft).

CHELlDO'XrUM, L.— A genus of P.ipa-
veraceous plants, remarkable for the yelli-w
juice contained in the laticiferous canals.
See Latex.

CHEUIFEPt, Leach.— A genus of Pseu-
doscorpiones (Arachnida).

Char. Cephalothorax with a transverse
furrow ; eyes 2 ; no tail.

C. cancroides (PI. -53. fig. 12). Brown,
palpi stout; length I". In old books, her-
baria, etc., and shady places.

C. muscorum. Palpi weaker; abdomen
with a small appendage at the last joint ;
reddish.

Many other species.

BiBL. Gervais (Walckenaer), Ins. Apt.
77 ; Murrav, Ec. Ent. 34.

CHEMICAL REACTIONS. [ 1G5 ]

CniLODON.

CHEMICAL REACTIONS. — iNTiio-
DUCTiox, p. xlii.

CHEMISTRY. — The following works
may be found useful for study or reference
in regard to chemical subjects: — Stockardt,
Mcj}er. Chem. ; (imeliii, Ilandhiirh ; Rose,
Anal. Chem. ; Will, Chetn. Analyse ; Fre-
senius, Anal. Chem. ; Heiutz, Zoochemic ;
Gorup-Besanez, Zooch. Anal. ; Schmidt,
Entw. ein. allg. UntersuclmngsmcfJiode ;
Iloppe-Sevler, Tr. iVanal. chim. phys. et
path. ; Miller, Chem. ; Watts, Diet. ; Roscoe,
Lessons l^c, and his larger work ; Eugel.
Chim. med. et hiol. ; Mehu, Chem. med. ;
Ralfo, Demonstr. in phys. and path. chem.

The progress of chemistry is reported in
the ' Chemical News.'

CIIEY'LETUS, Latreille.— A genus of
Acarina (Arachnida), of the family Trom-
bidina.

Char. Rostrum prominent, palpi very
thick, resembling arms, and falciform at the
ends; antenna! forceps (mandibles ?) didac-
tylous ; tarsi with 2 simple claws. Koch
describes 6 species ; Michael and Meguin
add others.

C. enulitiis (PI. 53. fig. 13). Found in
books and museums. Parthenogenesis has
been found to occur in this species (Beck).

C. 2}(ii'(tsitivonts, found at the root of the
hairs of rabbits, feeding upon Listrophori ;
C. heteropalpus, on the feathers of the Co-
lumbidse &c. ; C. macronychus, on the fea-
thers of Insessores ; C. venvstissimus, on
fodder in a stable ; and C.jiaheUifer, on the
w alls of a beer-cellar (Michael).

BiBL. Gervais, Walckenaer's Apteres, iii. ;
Koch, Deutsch. Cnistac. ^-c. ; Robin, J. de
VAnat.imi (figs.), p. 506: Beck, Mic. Tr.
1866, 30 ; Murray, Ec. Ent. 285 ; Michael,
Jn. Mic. Soc. 1878, 1-33 & 313 (figs.);
Megnin, Parasites, 1880, 240.

CHICKWEED, Stellaria media.— Th\s
common plant is of great interest to the
microscopic observer, on account of the
facihty with which the embryo-sac may be
dissected out. See Griflith, Text-book, 45,
pl.l.

CHICORY.— This substance, used for
mixing with or adulterating coffee, consists
of the roots of the plant of the same name
( Cichorrnm Intybus). The structures com-
posing the root (PI. 2. fig. 6) are recognizable
after it has been roasted and groimd, con-
sisting of membranous cellular tissue, c,
short-jointed reticulated ducts of large size,
b, and laticiferous tubes, a. Pure chicory
does not appear to contain any starch-gra-

nules, this substance being replaced by inu-
line in most of the plants of this family.
The presence of starch, therefore, in samples
of chicory denotes adulteration, which, when
effected by roasted corn or beans, is easily
detected ; and the integuments of roasted
grain may often be identified. Other com-
mon adulterations are roasted carrots, par-
snips, or mangel-wurzel : the first of these
is difficult to detect, as tlie structure of the
roots is very similar, as is the case to some
extent with the parsnip, in wdiich, however,
traces of the starch usually remain ; the
parenchymatous tissue of mangel-wurzel is
formed of cells very much larger than those
of chicory. In addition to the above, certain
substances containing astringent or colom'-
ing-matters are occasionally found in ground
chicory and coffee — such as oak-bark and
tan, mahogany and other kinds of sawdust.
These are easily detected by the micro-
scope, from the presence of woody fibre and
libsr-cells, the origin of which is often to
be made out by careful comparative exa-
mination.

BiBL. HassaU, Food and its Adulterations,
108, 199, .352.

CHPLODON, Ehr.— A genus of Infu-
soria, of the family Trachelina.

Char. Body covered with cilia ; mouth
with teeth arranged in the form of a tube ;
fore part of the head produced into a broad
membranous or ear-like lip.

The cilia form longitudinal rows.

C. cucullulus (PI. 30. fig. 27). De-
pressed, oblong, colourless, rounded at the
ends, slightly aiuiculate or beaked ante-
riorly on the right side ; freshwater and
marine ; length 1-1120 to 1-140 '. (PI. 30.
fig. 27 h, side view.) Contains a red eye-
spot.

C. uncinates. Depressed, oblong, rounded
at the ends, colourless; narrowed and curved
anteriorlv so as to appear hooked ; fresh w.;
length 1-430".

C. aureus. Ovato-conical, turgid, golden-
yellow, anterior end curved so as to form
an obtuse beak, posterior end naiTowed ;
aquatic; length 1-140". A Xassula (?).

C. ornatus. Ovato-cylindrical, golden-
yellow, ends rounded, a violet spot at the
neck; aquatic and marine; length 1-174".
A Nassula (?).

Dujardin admits only the first species ;
referring the others to the genus Kassvla.

BiBL. Ehr. Infns. .336; Duj. Inf. 490;
Stein, 7??/. i^c. ; Claparede and Lachmann,
Inf. 335.

CHILOMONAS.

[ 166 ]

CHLORASTER.

CHILOM'ONAS, Elir.— A genus of Fla-
gellate Infusoria, of the family JMonadiua.

Char. No tail nor eye-spot ; body ovoid,
oblong, siirmouuted by a lip ; with two very
delicate tiagelliform filaments ; revolving
upon its centre.

C. volvox. Oval, narrowed and notclied
in front, colourless and transparent, lip long;
fresh water ; length 1-1400".

C. paramecinin. Oblong, keeled, trila-
teral, coliiurless and opaque, sometimes ag-
gregated ; fresh water ; length 1-1020".

(J. destruens. Oblong, variable in form
fi-om its softness, colourless or yello^vish ;
fi'esh water and marine ; length 1-800".

C. gramdosa (PI. 30. fig. 28). Oblong,
broader in front, colourless, with granides
which appear to project on the surface ;
length 1-840". In an infusion of mosses.

C. ohliqua. Ovoid or pyriform, nodular,
colourless, variable in form ; length 1-2700".

BiBL. Ehrenb. Infus. 30 j Duj. Inf. 295;
Kent, Inf. 423.

CHILOSTOMEL'LA, Reuss.— A Fora-
minifer, consisting of subovate chambers,
overlapping one another, almost completely,
on opposite sides alternately; with crescentic
almost terminal aperture.

Fossil (Tertiary), recent (Atlantic and
Pacific).

BiBL. 'Re\v-s. Denhschr. Ak. Wien, 18o0,
i, 16 ; Brady, Qu. Mic. Jn. xix. 66.

CHIODEC'TON, Ach. — A genus of
Lichens (tribe Graphidei), of which one
species, C. myrticola, has been found in
Ireland ; and its var. sarniense in the Chan-
nel Islands.

BiBL. Leighton, Aug. Lich. 24, pi. 8. fig.
4, pi. 9. fig. 1 ; Lich. Flor. 435 ; Tulasne,
Ann. Sc. Nat. 3 ser. xviii. pi. 10.

CHIONY'PHE, Thienem.— A genus of
Mucorini (Phycomycetous Fungi), found
growing upon melting snow.

Chionyphe Carferi, Berk., is a curious
fungus, which is supposed to be the cause
of that formidable disease the Fungus-foot
of India. It has, however, been doubted
whether it is really the cause, or only
a secondary growth on the truffle-like
nodules composed principally of stearine (?)
which are characteristic of the disease.
Hogg considers the disease somewhat simi-
lar to the amyloid lardaceous disease which
attacks various other parts of the body.

BiBL. Thieneman, X(n-a Acta A. C. L. C.
xi. 1839 ; Ann. Sc. Nat. 2 ser. xiv. 03 ;
Intdl. Obs. 1862 ; Berkeley, Jn. Linn. Soc.
viii. 141, pi. 10; Carter, Ti: Med. and Vhys.

Soc. Bomhaij, 1861, 1862, 1863 ; Ann. N. H.
vol. ix. 442, 1862; Mn. Mic.Jn. 1871.

CHIROD'OTA, Eschsch.— A genus of
Echinodermata, closely allied to Synapta.

C. violacea possesses curious wheel-like
calcareous plates in the skin.

Not British.

BiBL. V. der IToeven, Zool. i. 150 ; Car-
penter, J//c/-oscq/je, 564; HerapathjQw. Mic.
Jn. 1865, 1.

CHITINE is the horny substance which,
gives firmness to the tegumentary system
and other parts of the Crustacea, Araclmida,
and Insects ; probably also the carapace of
the Rotatoria consists of it. It is left when
the above stiiictures are exhausted succes-
sively with alcohol, ether, water, acetic acid,
and alkalies, retaining the original form of
the texture. It is dissolved by concentrated
mineral acids without the production of
colour. It is not dissolved by solution of
potash, even when boihng. Neither does it
give the characteristic reactions ^^^thJMiUon's
or Schultze's tests. It contains nitrogen.

BiBL. Odier, Mem. Mus. d'Hist. N. i.
p. 35 ; Lassaigne, Compt. Rend. xvi. p. 1087;
Schmidt, Vercjl. Phys. d. toirbellos. Thiere
(Taylor's Sc. Mem. v. p. 1) ; Pay en, Compt.
Eend. xvii. p. 227.

CHLAMIDOCOC'CUS. See Proto-
coccus; also Cienkowsky, Lot. Zeit. 1865;
Rostafinsky, ibid. 1871 ; and liabenhorst,
Fl. AJq. iii! 94.

CIILAMID'OJ>ON, Ehr.— A genus of
Infusoria, of the family Euplota.

Char. Furnished with cilia and a cylinder
of teeth, but neither styles nor hooks. (Oxy-
tricha with a lorica and teeth.)

C. mnemosyne (PI. 30. fig. 29). Elliptical
or the anterior end somewhat broader, ovate;
green or colourless, and containing rose-red
vesicles ; lorica projecting beyond the body;
length 1-570 to 1-240"; marine.

BiBL. Ehr. Infus. 376 ; Kent, Inf.

CHLAMIDOM'ONAS (PL 30. fig. 30ff,
b, c, d, e). See Protococcus.

CHLAMYDOCYSTIS, Grunow, = Pro-
tococcics, part.

CIILORAN'Gimr, Stein, =CoLACir jr.

CII LOR ASTER, Ehr.— A genus of Fla-
gellate Infusoria.

Char. Single, free, a single fi'ontal eye-
spot, no tail, middle of the body with ra-
diate warty processes.

Allied to the genera Glenomorum and
Phacelomonas. Does not admit coloured
particles.

C. yyrans. Green, fusiform, acute at the

CHLORATE.

[ 107 ]

CIILOROGONIUM.

ends ; radiate processes in a whorl of four,
at tirst obtuse, then subacute ; flagelliform
filaments 4-5; length 1-1030"; freshwater.

It revolves radidly upon its axis, and
undergoes spontaneous division.

Two other species, one marine.

BiBL. Ehr. Ber. Bed. Ak. 1848, 236;
Kent, luf. .'ilo.

CHLORATE OF Potash. See Potash.

CHLO'REA, Xvl.— A genus of Lichens,
family Lichenacei, tribe Usnei.

6 species. C. vidpina occurs in Europe.

BiBL. Nyl. Syn. 274, pi. 8. f. 13-15; Jacq.
Misc. ii. pi! 10. fig. 4.

CHLORIDES. See the bases.

CHLOROCHYT'RIUM, Cohu.— A ge-
nus of Confervoid Unicellular Algae, allied
to Hydrociitium., Cliaracium, and Chj/tridiiim ;
consisting of single, globose-ovoid, or irre-
gularly curved, 2-3- or multilobed cells,
densely filled with green protoplasm ; first
diA-iding into larger segments, then separa-
ting into innumerable pyriform zoospores,
escaping through a tubular process.

C. lemnce. In the parenchyma of Lemna
trisuica ; diam. ^ jo".

BiBL. Cohn, Beitr. i. 1, 87; Wright, Tr.
Irish Acad. xxvi.

CHLOROCOC'CUM, Grev. — A genus
of Palmellaceae (Confervoid Algse).

We have assig-ned to this the common
green pulverulent stratum which is found
upon eveiT old tree, on all old palings and
other exposed woodwork, &c. K this proves
to be really a distinct plant, and not an
accumulation of germinating gonidia of
Lichens, it will still difter from the plants
we have assembled under the name of Pro-
toeoccKS in its general habit, especially in
the absence of zoospores. This point is,
however, still open to inquiry, since it
appears that the gonidia of the Lichens do
divide into two, fom", and eight, to form a
pulverulent stratum, which exactly repre-
sents Chlofococciim and Prutococcus.

Chi. vulgare, Grev. (PI. 7. fig. 1). A
collection of extremely minute cells, multi-
plying by division into twos and fom-s, no
gelatinous substratum, no zoospores. Dia-
meter of single cells 1-3000 to 1-4000"
(Protococciis viridis, 1-2000 to 1-3000"). Old
dry palings, bark of trees, iSrc. eveiywhere.
Calculating from the known size of the cells
and the wide distribution, this, if a species,
would appear to be the most fecund A.lga
in existence. There are 300 millions of in-
dividuals on a square inch, in a layer 1-100"
thick ; and such layers clothe almost every

piece of unpainted timber and old trunk we
meet with in the country. C. murorum, Gr.
is perhaps a Palmoyhcd, Kiitz.

Rabenhorst remarks that this species
closely resembles the gonidia of Lichens,
but that the cells have a nucleus, which is
wanting in the Licheii-gonidia. This is,
however, incorrect, as the nucleus is quite
distinct in these gonidia.

Rabenhorst describes 12 species ; but
places C. vuhjare in the genus Pleurococcus.
BiBL. Greville, Crypt. FL pi. 262; Has-
saU, Algte, pi. 81. fig. 5.

CIILOROGONIUM, Ehr.— A genus of
Infusoria, of the family Astasitea.

Char. A red eye-spot, a tail, and two
anterior filaments. (ISf ot attached by a fixed
pedicle.)

C. euchlornm (PI. 30. fig. 31). Spindle-
shaped, acute at each end, tail short ; length
1-1150 to 1-280". Found in enormous
numbers in pools and puddles ; frequently
as many as 10,000 in a single drop.

These organisms do not admit colouring-
matter or foreign bodies ; hence they are
probably not Infusoria, but Algae. They
often adhere to each other in gi'oups by the
so-called tails (PI. 30. fig. 31, upper figure),
sometimes to foreign bodies (PI. 30. fig. 31,
lower figure), which exhibits themadheiing
to a dead Vorticella).

They undergo oblique spontaneous divi-
sion (PI. 50. fig. 1) ; this commences in
the internal substance, which is constricted
before the outer portion.

They also propagate by a process of
swarming, which takes place thus : the in-
ternal substance first separates somewhat
from the transpai'ent wall, subsequently
becoming irregularly constricted at various
parts. The constrictions deepening, the con-
stricted portions separate from each other as
independent vesicles (?), and the internal
substance acquires the appearance of a black-
berry or bunch of grapes, consisting of a
fusiform aggreg'ation of uniform longisli oval
granules. Up to this period, the parent
organism continues its movements ; subse-
quently these cease. The granules have
now acquired independent vitality, and their
filaments become developed. The envelope
then brefiks near its middle, and the swarm
of young ones escape. In their somewhat
more developed stage they form Glenoino-
rum timjens, Ehr. See Protococcus.

BiBL. Ehr. Infus. 113; Weise, Wieg-
manns Archiv, 1848, i. 65; Stein, Infus,
188.

CHLOROPHYLL.

[ 168 ]

CHLOROPHYLL.

CHLOR'OPHYLL (leaf-green). — The
name applied to the green colouring-matter
of plants. The nature of tlie substances which
are understood under this term is still some-
what questionable. It is ordinarily stated
that chlorophyll exists commonly under the
form of globules or granules, and occasion-
ally as an amorphous granular substance,
in either case more or less adlierent to, or
imbedded in the primordial utricle of the
cell. It is, lioweyer, a contested point
whether the chlorophyll-corpuscles are se-
misolid homogeneous globules in which the
chlorophyll is imbedded, or vesicles com-
posed of a delicate membrane enclosing a
green liquid : the former view is now, how-
ever, g'enerally adopted. Chlorophyll pre-
sents itself in the form of distinct corpus-
cles (f/ranuku of authors), in the cells of
the flowering plants generally, particularly
the parenchyma of leaves and the subepi-
dermal parenchyma of green stems and
shoots. The granules are especially large
and distinct in certain water-plants, and
may be well seen lying scattered, singly,
imbedded in the circulating protoplasm of
the cells of the leaves of Vallianeria and
other water-plants. The corpuscles are very
evident in the cells of the prothallia of
Ferns, in the leaves of SelcKjineUa, of Mosses
and Liverworts ; also in Chcira, where they
are very abundant and form a continuous
layer, or numerous rows, embedded in a
gelatinous stratum between the cell-w^all
and the circulating mass of protoplasm. In
the Oonfervoids the chlorophyll often ap-
pears both formless and corpuscular in one
and the same cell, but usually more or less
formless in young cells, and more com-
pletely converted into granules in the full-
grown, as in Vaucherin. In the Confer-
vacoa3, such as Cladophorn., and in CEdogo-
niuni, it presents itself in a granular stratum
with numerous larger bright corpuscles ;
and in Hpinxiyra, Zi/tjnema, &c. the chlo-
rojiliyll takes the form of tlie spiral or an-
nular band to which it is adherent, without
large granulations in the general mass, but
with a number of distinct, larg(;, bright-
looking corpuscles at intervals (I'l. Si. fig.
18). In Profococcus, in zoospores, and in
the indiyidual ciliated bodies of the Vol-
vocineai, the chloropliyll appears to tinge
the general mass of granular protoplasm,
leaving the conical apex (beak) uncoloured
(I'lates 7 & 9), while more or less distinct
corpuscles or granules are scattered through
tie mass, varyiu"' in number and size at

different periods. When any of these forms
of chlorophyll are treated with ether, benzole,
alcohol, or chloroform, the colour is abstract-
ed, while the organized forms, the corpuscles,
&c., remain ; so that the true chlorophyll is
really only a soluble substance, dyeing the
bodies called chlorophyll-corpuscles &c.
It becomes a question then whether these
are homogeneous semisolid corpuscles, or
vesicles containing the colouring-matter in
sacs,' from whicli it is extracted by the ether
&c. Nageli and others assert the vesicular
chai'acter of the chlorophyll-corpuscles and
the appearances are sometimes much in
favour of this view ; but in the many cases
in which Ave have obtained the appearance
of a double line around them, under high
magnifying powers, we have never been
able to divest ourselves of the impression
that this was an optical illusion. Nageli
asserts that the corpuscles multiply by di-
vision, which is true, but does not prove
that they are vesicular structures. The ob-
servation of Giippert and Cohn, of a chlo-
rophyll-corpuscle swelling up and bursting
through endosmose, may be explained with-
out supposing a regularly organized coat.
We are inclined to believe that tlie bodies
bearing the green colouring-matter are
structures belonging to the protoplasm, the
green colour being only an additional clia-
racter, produced by the action of light,
superadded to the ordinary character of the
granular structurs occurring in the proto-
plasm or nitrogenous cell-contents. See
Protoplasm.

A very important point connected with
chlorophyll is its relation to starch. The
bodies called starch-granules occur very
commonly with clilorophyll-corpuscles in
the cells of the green parts of plants, and
they become substituted for each other
under varying circumstances. Some authors
have imagined that chlorophyll is produced
by a chemical decomposition of starch,
while others think tliat starch is deyeloped
from chlorophyll. The chief ground for
the latter view is the fact that starch-
granules are often found in the centre of
chlorophyll-corpuscles, like a kind of nu-
cleus. "We have traced, in Hepaticie, the
gradual formation of a group of starch-
granules in the interior of a chlonjpliyll-
corpuscle (where they are readily detected
by the application of iodine) ; and this goes
on in certain cases until almost all the green
colour is lost. Starch occurs universally
at a certain period in the bright distinct
>

CIILOROrilYLL.

[ 1C9 ]

CIILOROrHYLL,

chlorophyll-corpuscles of Chara and of
the Confervacejc, iSj>iroi/i/ra &c. ; so tliat
these are coloured blue by iodiue, although
green before its application. But this starch
may disappear agaiu in the course of nature,
for it always vanishes from these corpuscles
wheu they are about to become organized
into zoospores. In tact the green chloro-
phyll is predominant dm-ing active vegeta-
tion, and starch in periods of rest or in full-
grown structures. Moreover, while chloro-
phyll may appear independently in young
cells without being preceded by starch, in
green tissues starch makes its appearance
without previous existence of chlorophyll-
corpuscles in subterranean structures, as for
example in the potato and other tubers.
The truth of the matter therefore appears to
be, that the chlorophyll-structures, as above
stated, are granular structures belonging to
the general protoplasm or nitrogenous cell-
contents, that they become coloured green
in the light by a chemical change connected
with the vital processes, and that in under-
going this change they do not lose the power,
which the ordinary protoplasm possesses, of
secreting starch and decomposing it again
when required for the nutrition of the plant.
Starch-granules, when free and uucoloured,
appear to be produced originally from gra-
nular or vesicular protoplasmic structures,
only differing by absence of colour from
chlorophyll structures. For example, the
granular protoplasm around the cell-nucleus
in the cells of herbaceous Monocotyledons
(such as the Lily, Tradcscanfia Szc.) will
sometimes become converted into chloro-
phyll- granules (in superficial cells), inside
which stai'ch may be subsequently deve-
loped ; but (in deeper-seated cells) the
granular protoplasm may give rise at once
to starch-granules (PI. 46. fig. 28 a) with-
out the previous existence of the green
modification of the protoplasm, i, e. chloro-
phyll.

The views of the nature of chlorophyll
above expressed (in the first edition of this
work) have been since confirmed by the
observations of v. Mohl and Gris ; and re-
peated observations have furnished us with
similar results. In Caspary's observations
on Ilydrillefe also, will be found confirma-
tion of the statement that the supposed
vesicular structure is an illusion.

Chlorophyll occurs in the animal, as well
as in the vegetable kingdom — thus in Infu-
soria {Stentor &c. ), the zoophytes {Hi/dra),
the TurbeUaria, Aphidse, &c.

Chlorophyll-corpuscles, when set free in
water, expand by imljibing water, some-
times becoiuing vacuolated and bursting.
Alcohol and most acids coagulate them,
while acetic acid will often blend the cor-
puscles into an irregular mass.

After the separation of the chlorophyll,
the protoplasmic base retains both its form
and volume ; constituting a solid soft body,
often containing small vacuoles.

Chlorophyll is turned yellow-brown by
tincture of iodine ; sulphuric acid gives it a
more or less deep blue colour ; ether and
alcohol discharge the green tint. Prepara-
tions mounted in chloride of calcium or
glycerine often lose their green colour; those
preserved in water will sometimes retain it
a long time. The green colouring-matter
extracted by alcohol is a complex substance,
containing a kind of wax and a matter
allied to indigo.

It was formerly considered that chloro-
phyll was the only colouring-matter of
plants, capable under the infiuence of oxy-
gen of producing all the varied and beauti-
ful colours of flowers. Subsequently, two
colouring-matters, a blue-phyllocyanine, and
a yellow-phylloxanthine, have been sepa-
rated by chemical reagents, and considered
as the real colouring-matters, which by
their mixture produced the most varied
colours. The old view has lately been re-
vived ; but the whole question must at
present be considered as unsettled.

In autumn, at the fall of the leaf, the
chlorophyll becomes dissolved, and con-
veyed to the perennial portions of the plants,
the cells become filled with liquid contain-
ing crystals and a number of bright yellow
granules ; if the leaves are red, this arises
from a substance dissolved in the liquid, the
yellow granules being also present.

BiBL. Mohl, Ve(/et. Cell. {Transl. 1852),
41 ; Vennischte Schriften, 34'J ; Botan. Zcit.
1855 {Ann. N. H. 2nd ser. xv. 321);
Nfigeli, Zeitsch. f. wiss. Bot. iii. 110 {Bay
Soc. 1849); Milkier, Physiol. Chem., Tr.
266; Goppertand Cohn, But. Zeitmuj, 1849,
vii. 665; Schleiden, Grunrhi'iye wiss. Bot.
3rd ed. 196 ; Braun, Verjiinr/. {Bay Soc.
1853, 195); Morot, Colo?: cksVer/etaux, Ann.
Se. Nat. 3 ser. xiii.« 160; Guillemin, ^n«,
Sc. Nat. 4 ser. vii. 155; Gris, ibid. 1857,
vii. 179; Casparv, Primjsheim's Jahrh. xoiss.
Bot. i. 399, ibid. 1881; Fremy, Compt.
Bend., 1. 405 ; Gmelin, Ilandb. Ghent, vii.
1430 ; Ilofmeister, PflanzntzcUe, 1867, sect.
41 ; Kraus, Jahr. ivissensch. Bot. 1871, viii.

CHLOROPTERIS.

[ 170 ]

CHOLERA.

131 ; Henfrey-Masters, Bot, 498 ; Saclis,
Bat. 72\}; Sorby, Beale, IIoiv ^-c, 278;
Kvaus, Z. Kenntniss. d. CM. Farbstoffe, 1872
(Spectroscope) ; Askenasy, Bot. Zeit. 18G7,
225 ; Geddes, Proc. Boi/.'Soc. no. 194 (Qn.
Mic. Jn. 1879, xix. 434) ; Palmer, M. M. J.
1877, xvii. 22.J (figs.).

CHLOROP'TERIS, Mont.— A genus of
Confervacese (Confei-void Algfe).

1 species : not British. Rabenhorst, Fl.
Alq. iii. 346 (fig.).

CHLOROSPILE'RA, Honfrey (Ere-
MOSPH^EA, De Bary). — A genus of Uni-
cellular AlgJB, prolDably related to Q3do-
gonieoe (Rabenliorst places it among the
Palmellaceiie) ; of which one species, C. Oli-
veri {E. viridis, De B.) (PI. 5. fig. 4) is
known, consisting of a single globular cell,
about 1-200" in diameter, densely filled with
green contents, sometimes exhibiting a radi-
ated appearance. The cell is multiplied by
dividing into two parts by a septum, and
forming a new perfect cell in each half, the
two new cells escaping through slits in the
parent-cell membrane, with elasticity, when
mature. Resting-spores, formed in fours
in a parent-cell and of a brown colour, have
been observed, but not their germination
nor any formation of zoospores. C. Oliveri
was found in a boggy ditch, at Prestwach
Car, Northumberland. It has been found
elsewhere in turfy pools.

BiBL. llenfrey, Mic. Trans. 1859, vol. vii.
25 ; De Barv, Cotrj. 56.

CHLOROTYLIUM, Ktz.— A genus of
ChtetophoracejB ((^onfervoid Alga3).

Char. Filaments jointed, repeatedly di-
chotomous, parallel ; joints of two kinds,
some elongate and colourless, others swol-
len, abbreviate, and with green eudo-
chromes.

4 species. On rocks, submerged timber,
and the bottom of ponds.

BiBL. Kiitziug, Sp. Alg. 432 ; Raben-
horst, Fl. Alq. iii. 386 (fig'.).

CHOCOLATE. See Cocoa.

CHCE'NIA, Quennerstedt.— A genus of
Holotrichous Infusoria.

Char. Free, elongate, with a brush-like
tuft of large cilia at the anterior extre-
mity.

C. teres, marine, = Trachelius t. Duj,

Btbl. Kent, Inf. 521.

CIIOIROMY'CES.— A genus of Tube-
racei (Ascomycetous Fungi) characterized
by a definite base, even common integu-
ment, clavate nsci and splierical sporidia.

C. meandrifonnis, Vitt., occurs occasion-

ally in Great Britain. It sometimes attains
a considerable size.

BiBL. Vitt. Mon. Tab. 50; Ann. N. H.
xviii. 80 ; Sow. Fung. t. 310 ; Tul, Fung.
Hyp. 170, tab. xix. fig. 7.

CHOLERA.— The attempt has often
been made to discover some animalcule or
minute vegetable organism in the air, water,
and the intestinal and other animal liquids,
daring the existence of cholera, which might
explain the origin of this fearful disease ;
and statements have been published an-
nouncing success. None of these have,
however, stood the test of rigid investiga-
tion. When the cholera prevailed at Berlin
in 1832, the renowned Ehrenberg, who had
then been engaged in the study of micro-
scopic organisms for many years, declared,
after special and careful examination, that
neither the air nor the water from various
localities contained any thing unusual. Re-
peated examinations of the air and water
of infected localities, made in 1849, and
dui'ing the more recent accessions of the
cholera, have afforded also conclusive nega-
tive evidence.

Hallier subsequently attempted to show
that it was probably derived in the first in-
stance from a fungus infesting rice. It is,
however, a remarkable fact that rice is ftir
less subject to attacks of Fungi than any
other cereals. The researches of Thwaites
and others have been directed to this espe-
cial point, and have in no respect confirmed
Hallier's views; added to which, it was
quite evident that the fungus which ap-
peai'ed in cholera-evficuations was not the
Urocystis, to which he referred it. De
Bary altogether denied the justice of his
views. Lewis and Cunningham were placed
by the government authorities in communi-
cation with De Bary and Hallier, and quite
accorded with the former of the two ; and
the very careful observations of Lewis at
Calcutta confirm De Bary's views. See

MiCROZYMES.

The methods of examining the air in re-
gard to this point are described under
Air.

BiBL. Baly and Gull, Bep. of Cliolera
Suhconvnittee of Boy. Coll. Phys., London,
1849; Robin, 'T^e^e^;. Parasites, S,-c., 1853,
appcndice, 076 ; HaUier, Das Cholera-
Co)ifagium ; Privy Council Beports, 186()and
1870; Sansom, J^/J. of Science, 1871, 153;
Berkeley, Mic. Jn. July 1869 ; Lewis, Be-
port on Objects found in Cholera-evacuations;
and Med. Chi. 'Bev. 1871.

C HOLER A-FLY.

[ in ]

CHORDA DORSALIS.

CriOLERA-FLY.— Knox, Lancet, 1853,
ii. 471).

CllOLES'TERINE. — This substance
exists naturally in most animal liquids in a
state of solution ; also in many animal solids,
as in the blood, the bile, the meconium,
the brain and spinal cord. As an abnormal
product, it occurs in the crystalliuo form in
the bile, biliary calculi, various dropsical
effusions, the contents of cysts, pus, old
tnbercles, malignant tumours, the excre-
ments, expectoration of phthisis, &c.

In the vegetable kingdom it occurs in
peas, beans, almonds, many seeds, &c.

The crystals form thin pearly rhombic
plates (PI. 13. fig. 21). The acute angles
are =79° 30', the obtuse =100° 30'. Some-
times the angles are truncated.

Cholesterine is insoluble in water and
solution of potash, even vi^ien boiling ; but
soluble in ether and boiling alcohol, crystal-
lizing on cooling.

It is most easily procured from a gall-
stone by boiling in alcohol ; it falls on cool-
ing. The crystals thus obtained are usually
thicker than the natural plates.

CHONDRACAX'THUS.— A genus of
Crustacea, of the order Siphonostoma, and
family Lernaeopoda.

C. Zei. Found upon the giUs of Zeus,
the Dory. Body is covered with short re-
flexed spines. Length 4-5".

BiBL. Baird, Brit. JEntomostr. 327 ; Me-
gnin. Parasites, 442.

CHONDRIA, Ag. See Latteencia.

CHONDRINE.— The gelatinous matter
of the permanent true cartilages.

Its solution differs from that of the gela-
tine of bones &c., in being precipitated by
acetic acid, acetate of lead, and alum. The
acetic precipitate is insoluble in excess.

It is coloured red by MiUon's test ; but is
imaffected by th at of Pettenkofer.

CHOX'DRUS, L.— A genus of Crypto-
nemiaceae (Florideous Algae), composed of
cartilaginous sea-weeds with flat dichoto-
mously-divided fronds, the cellular structure
of which exhibits three layers — a central of
longitudinal filaments, an intermediate of
small roundish cells, and an outer of ver-
tical coloured and beaded rows of cells,
the whole imbedded in a tough " inter-
cellular " matrix. See Intercbllulae,

SUP.STAXCE.

Fructification : spoirs contained in favel-
lidia immersed in the frond ; tctraspores
collected in imbedded sori ; and " nema-
theciaj' tubercles composed of radiatino-

filaments (anthoridia ?). C crispus becomes
horny when dry, and is the liish moss or
Carrai/een of the shops.

BiBL. Harvey, Br. Mar. Alg. pi. 17 D ;
Phyc. Brit. pi. 63 & 187 ; aieville, Alg.
Brit. pi. 15.

CHOR'DA, Stackh.— A genus of Larai-
nariaceae (Fucoid Algte), with fronds of
a pecidiar, simple cylindrical form ; two
species, CjHutnanil Clomeiitaria, ?iYe found
between tide-marks on British coasts ; the
former grows from 1 to 20 or even 40 feet
long, with a greatest diameter at half its
length, of 1-4 to 1-2". The cord-like frond
is tubular, but has at intervals thin dia-
phragms, formed by interwoven transparent
filaments. The wall of the tube is com-
posed of a number of layers of very regular
six-sided cells, upon which are implanted
little erect clavate cells which coat the
entire surface of the frond. These present
two forms, apparently constituting oospo-
7'anr/es {spores, Harvey, pr»7//;e«K<^«, Ag.)
and trichosporatKjes, {cmtheridia, Harvey,
spores, Ag.). The first are single sacs pro-
ducing a number of zoospores; the second
are filaments composed of about five joints,
each of which gives birth to a zoospore.

BiBL. HarveV, Br. Mar. Ah/. 31, pi. 3 B;
Pht/c. Brit. 107, &c. ; Thuret, Ann. Sc. Nat.
3 s'er. xiv. 240, pi. 29. figs. 5-10 ; Derbes
and Sober, Ann. Sc. Kat. 3 ser. xiv. 208,
pi. 33, figs. 7-10 ; Kutzing, Phyc. gen. pis.
28 & 29.

CHORDA DORSA'-

i

a-

Fio-. 126.
LIS, or NoTociioRD. — °

The embryonic represen-
tative of the spinal co-
lumn of the Yertebrata ;
the permanent spinal
column of the Cartilagi-
nous Fishes. It some-
times forms a spindle-
shaped, transparent, gela-
tinous-looking cord, with
the broadest part near
the tail ; at others it is
cylindrical or conical,
rounded anteriorly and
tapering posteriorly.

It usually consists of
an outer comparati-vely Magnified 350 diam.

thick and firm structure- Portion of the chorda
1 1 p ■ „ dorsalis of the embryo

less membrane, forming „f^ ^^eep, rather more
a sheath, and of pale nu- than 1-2" in length, a,
cleated cells, which fill sheath; 6, ceUs.
the sheath (fig. 120). In
some instances, however, its structure is

CIIORDARrA.

[ 172 ]

CHROMOPHYTON.

fibrous, and that of the sheath fibro-mem-
branous. The cells are mostly angular or
polyhedral, and closely crowded. Their
size varies; in the embryo of a sheep rather
more than 1-2" in length, they measured
about 1-1800".

The walls of the cells readily dissolve in
solution of potash ; but they yield neither
gelatine nor cliondrine on boiling. The
liquid Avithin the cells is not coagulated by
boiling, but the chorda itself becomes cloudy
and granidar.

In its earlier stage of development, the
chorda consists simply of a longituduial
band of ordinary formative or embryonic
cells ; the sheath is subsequently formed.
It appears that the spinal column is not
developed from the chorda itself, but from
a blastema secreted by its component cells
and effused around them.

The chorda is most readily examined in
the larvae of frogs (tadpoles), of Tritons,or of
Fishes, and may be separated by macerating
the dead animals for twenty-four hours in
w^ater. On cutting off the tail, it may then
be pressed out by gently scraping along its
course from the end of the tail, or from the
head towards the wound. It is a beautifully
delicate structure, and closely resembles in
appearance a piece of vegetable cellular
tissue.

BiBL. Kolliker, Mihr. Anat. ii. 346;
Stannius, Verql. An.; Gegeubaur, Vert/. An.
450 ; Frey, Hist. 197.

CHORDA'KIA, Ag.— A genus of Chor-
dariacea3 (Fucoid Algce), remarkable for the
solidity of the cellular texture of the fili-
form fronds. The axis and branches are
composed of a central mass of longitudinal
cells, upon which stand horizontal clavate
filaments, formed of a row of beaded cells,
constituting a distinct peripheral layer,
which gives a velvety texture and slimy
character to the surface. The so-called
spores attached to the liorizontal filaments
are oosj)oranf/es, and discharge zoospores
when mature ; trichosporanges have not yet
been observed. CJlaffellifonnis, MuW., is
common on rocks and stones between tide-
marks.

BiBL. Harvey, Br. Mar. Ah/, pi. 10 A ;
P/n/c. Brit. pi. ill ; Thuret, Ann. Sc.
Nat. 3 ser. xiv. 237.

CTIOHDARIA'CEyE.— A family of Fu-
coid Alg;e. Olive-coloured sea-weeds with
a gelatinous or cartilaginous, branching
frond, composed of vertical and horizontal
filaments uiterlaced together; the uospo-

ranges and trichosporanges attached to the
filaments forming the supei'ficial layers of
the frond. British genera :

Chordaria. Axis cartilaginous, dense fila-
ments of the circumferauce unbranched.

Mesocfloia. Axis gelatinous, loose fila-
ments of the circiuufereuce branching,

BiBL. Harvey, Marine Algce ; Thuret,
Ann. Sc. Nat. 3 ser. xvi. o, &c. See also
the genera.

CHORIOP'TES, Gervais.— A subgenus
of Sarcoptes, with the body bilobed, or
notched posteriorly, the mandibles short,
didactylous, the tarsi with strong claws,
and very large suckers.

C. bovis (spathiferns) ; on the legs and
hind quarters of the horse, the goat, and
the ox ; C. setifertis, on the hyseua and fox ;
C. ecaudatus, in the ears of dogs, cats, and
ferrets. There are other doubtful species.

BiBL. Megnin, Parasites, liJS (figs.) ;
Murray, Ec. Entom. 312 (fig).

CHORIZOP'ORA = Lepralia pt. C.
Brominiartii. Cells connected by a tubular
network. Marine.

BiBL. Hincks, Pohjzoa, 222.

CHOROID MEMBRANE. See Eye.

CHROMATE OF LEAD (neutral) is ,.ne
of the best materials for coluuring size in
injections. See Lvjection.

CHROMIC ACID may be prepared by
adding gradually from 120 to loO parts, by
volume, of pure concentrated sulphuric acid
to 100 parts of a; cold saturated solution of
bichromate of potash. The crj-stals of the
acid separate as the solution cools. The
mother-liquor should be poiu'ed off", and the
crystals dried upon a tile; they may be
ptu'ified by re-crystallization from solution
in water. With excess of sulphuric acid,
chromic acid is a valuable reagent for
dissolving the intercellular stibstance of
phints.

Chromic acid is readily decomposed by
organic matter, as dust &c., and must
therefm-e be preserved in a well-stoppered
bottle. Its aqueous solution, which should
be of a pale yellow colour, is used for
hardening and preserving nervous and mus-
cuhir tissues, &c. It should bo prepared
when required.

CIIROMOPirYTOX, Woronin. — A
doul)tful organism, probably allied to the
Palmellaceoo, forming a yellow isli-brown
dust on the surface of boggy pools (Finland).
Two forms were met with : the larger con-
sisted of splicrical moniliform or variable
bodies, composed of a hyaline matrix, con»

CllPtOOCOCCUS.

[ 1'3 ]

CIIYLAQUEOUS.

taininpr rounded or ribbon-shaped yellow 1-
ciliated zoospores, l-oOOO" long, each with a
yellow pig'iueut-spot, and containing one
or two contractile vesicles ; these multi-
plied by division. The finer had the same
composition as the larger. Resting-spores
were formed in the empty cells of Sp/Kignum
and ILjpniim, from which the motile forms
were traced.

C. liosaiioffii, the single species.

BiBL. Woroniu, £ot. Ze.if. 1880, 62o,
6-11 ; Jn. Mic. Soc, 1881, i. 100.

CHROOCOC'CUS, Nag. See Peoto-
coccus. Eabenhorst retains this, as a
genus, with 23 species.

CIIROOLEPUS, Ag.— A generic name
applied to certain byssoid structures found
on rocks, bark of trees, &c. They consist
of jointed, variously branched filaments, the
joints expanding to form sporangia, filled
with biciliate zoospores. C. aureuin (PL
3. fig. 7 ) is composed of rigid opaque, ulti-
mately brittle filaments, forming soft cush-
ions of a yellowish colour; (J. Jolitlius,
odoratum, and lichenicola are of orange or
fulvous colour. Another series of species,
C. ehenea &c., are black, or purple. These
plants have been regarded sometimes as
Fungi and sometimes as Algae.

Rabenhorst describes 11 species: the
genus forming the type of the family Chro-
olepidfe (Confervoid Algae). Reproduction
by biciliated zoospores. Some species emit
a violet-odour.

BiBL. Hooker, Brit. Flora, v. pt. 1. 384 ;
Enyl. But. pi. 702 & 1G39 ; Kiitzing, Spec.
Ahj. 42-5; Casparj^, Flora, 1858, oOlj Ea-
benhorst. Fl. Ah/, iii. 371.

CHRYSALlbl'XA, D'Orb.— A Textu-
lariiin Foramiuifer, with a tviserial arrange-
ment of chambers and with large pores,
and sometimes tubes, opening fi'om chamber
to chamber. C'h. gradafa, D'Orb., is from
the Cretaceous strata of France. A dimor-
phous form, which is imiserial in its old
state, lives in the Indian ocean and Panama
Bay.

BiBL. D'Orbigny, For. Foas. Vien. 194;
Cai-penter, Introd. Forum. 193.

CHRYSBIE'XIA, J. Ag.— A genus of
Laurenciacese (Florideous Algi>j).

C. ckivellosa is a red sea-weed 3 to 12"
high, forming a feathery frond composed of
a branched, tubular, long, not constricted or
chambered, cellular structm-e, filled with a
watery juice. The spores are angular and
are contained in dense tufts in ceramidia
borne on the sides of the branchlets. The

tetraspores are 3-partite and immersed in
the branclilets.

BiBL. Ilarvev, Br. Mar. Ahj. pi. 13 A;
Phyc. Brlt.vl 114.

CIIRYSO'MOXAS, Stein.— A genus of
Flagellate Infusoria.

C. JiavicaHs = Manas fl. Ehr. ; has the
body ovate, a terminal flagellum, two
lateral colour-bands, no dilated pharynx,
and an eye-spot. Ditch water.

BiBL. 'Kent, Infus. 408.

CHRYSOPYX'IS, Stein.— A genus of
Flagellate Infusoria.

Char. Bodies o^ ate, contained in a sessile
lorica ; flagella 2, equal ; two colour-bands,
but no eye-spot.

C. bijies. Lorica with two posterior
spines. Attached to the cells of Mougertia
or other freshwater algae.

BiBL. Kent, Infus. 408.

CHTHONOBLAS'TUS, Kiitz. See Mi-

CROCOLEUS.

CHY'DORUS, Leach {Li/nceus, Miill., in
part). — A genus of Entomostraca, of the
order Cladocera, and family Lynceidae.

Char. Nearly spherical ; beak very long
and sharp, curved downwards and forwards ;
inferior antennjB very short.

_ C. sphcericus (PL 20. fig. 7). Shell smooth ;
oUve-green, Found in ponds and ditches.

C. globosus. Shell more rounded than in
the last, and nearly six times as large ; an-
teriorly reddish, with circular striae and
numerous black spots ; fresh water.

BiBL. Baird, Brit. Evtom. p. 125 ; Nor-
man and Bradv, Brit. Fnton. pp. 47, 48.

CHYLA'QUEOUS or chylo-aqueous li-
quid and system.

In the Invertebrata, two distinct kinds of
nutrient liquids exist. In some classes of
this subkiugdom. these two liquids coexist
in the same organism, though contained in
distinct systems of conduits ; while in others
they become united into one. Williams
distinguishes these two kinds of liquid as
the Uood proper or true blood, and the
chylaqiieous liquid. The former is always
contained in definitely organized (walled)
blood-vessels, and has a determinate circu-
latory movement ; the latter, with equal
constancy, in chambers, irregular perivis-
ceral cavities, and eells communicating in-
variably with the peritoneal cavity ; not
having a determinate circulation, bufe a to-
and-fro movement, maintained by muscular
and ciliary agency. The true-blood system
does not exist under any form, even the
most rudimentary, below the Echmoder-

CHYLE.

[ 174 ]

CHYTRIDIUM.

mata ; in other words, the true-blood sys-
tem beo'ins at the Echinodermata. Below
the Echinodermata, viz. in the Polypi and
Acalephse, the digestive and circulatory
systems are identified, consequently the ex-
ternal medium is admitted directly into the
nutrient vessels. This circumstance con-
stitutes a fundamental distinction between
the chylaqueous system and that of the true
blood, into which, under no conditions, is
the external inorganic element directly
introduced.

In every class in which the chylaqueous
liquid exists, it is charged more or less abun-
dantly with organized corpuscles. These
corpuscles are marked bj' distinctive cha-
racters, not in different classes and genera
only, but in different species, entitling these
bodies to great consideration in the esta-
blishment of species. In those classes, as
the Echinodermata, the Entozoa, and Anne-
lida, in which, in the adult animal, these
two orders of liquids coexist, though dis-
tinct, in the same individual, an inverse
proportion prevails between them, as re-
spects their magnitude or development.
The system of the chylaqueous liquid does
not exist in the adult, but only in the larval
state of the higher members of the articu-
lated series, as the Myriapoda, Insecta, aud
the Crustacea.

BiBL. Williams, Trans, and Proc. of Roi/.
Soc. 18o2 (thefoi-mer contains figures of the
corpuscles) ; id. Ann. N. H., passim after
1852 ; Agassiz, Sieb. and Kiill. Zeitschr.
1856, vii. 17(5; Nicholson, Zool. 1878.

CHYLE. — The chyle consists of a llqiud
which coagulates when removed from the
vessels, containing in suspension molecules,
nuclei, colourless corpuscles, and colom'ed
blood-corpuscles.

The molecules (PI. 50. fig. 2 «) are very
numerous, and probably consist of fatty
matter surrounded by a coat of a proteine-
compound ; to them is owing the milky ap-
pearance which the chyle possesses during
active digestion. They form the molecular
base of Gulliver. The free nuclei (PI. 50.
fig. 2 b) have a somewhat homogeneous
aspect; thev are not numerous, about
1-11,000 to 1-5000" in diameter, frequently
appearing cell-like and granular after the
addition of water. Tliey are only met with
at the origins of the lacteals, in the mesen-
tery, and in tlie vasa efFerentia of the me-
senteric glands, but never in the thoracic
duct. The chyle-corpusrles (PI. 50. fig. 2 c),
which are identical with those of the lymph

and the colourless corpuscles of the blood,
are pale, round, nucleated cells, 1-4500 to
1 2000" in diameter ; their contents be-
come tm-bid when water is added; and they
are rendered very transparent by the addi-
tion of acetic acid, the granular nucleus
becoming at the same time very distinct.
Sometimes they exhibit a number of Amoe-
ba-like processes (PI. 50. fig. 2 d). At the
origins of the lacteals the chjde-corpuscles
are few in number, or even absent ; near the
mesenteric glands, they are met with under-
going division. The coloured blood-corpus-
cles are probably derived from without.
Chemically, the chyle consists of a saline
liquid, containing albumen and fibrine in
solution, the latter when coagulated form-
ing a soft and loose clot.

BiBL. Kiilliker, Mikrosh. Anat. ii. 561 ;
Wagner, Handwort. art. C'hylus ; id. Elcm,
of Fhys., by WiUis; Gulliver, 6^e;-ie/-'5 Anat.;
Lister, Diihlin Hosjt. Gaz. 1857, 347 ; Frev,
Hisfol. 8,-c. p. 140 ; and the Bibl. of Che-
mistry.

CHYLOCLA'DIA, Grev.— A genus of
Laurenciacefe (Florideous Algye), containing
a few British species, with fronds of small
size, composed of a branched, cylindrical
and tubidar structure, cut off" into chambers
within by diaphragms at intervals, and filled
with a watery juice. The walls are com-
posed of small polygonal cells. Niigeli has
given the minute anatomy oW.(Lo?nentaria)
Icalifornis. The . spores are wedge-shaped,
contained in tufts in ceramidia borne on the
branchlets. The tetraspores, 3-partite, are
immersed in the branchlets.

BiBL. Harvey, Mar. Ah/, pi. 13 B ; Pln/c.
Brit. pi. 145, &c.; Grev. 'Ah/. Brif. pi. 14;
W».ge\\, Alr/en-systeme, 246, pi. x. figs. 13-21.

CHYTRID'I'UM, Braun.— A genus of
Unicellular Algae, perhaps allied to the Myx-
omycetes (Sachs), consisting of minute, glo-
bose or pyriform, usually colourless cells,
operculate at the sunmiit, with a root-like
base, attached to Confervoid or allied plants,
and penetrating their cell-walls. Zoospores
very numerous, glob'ilar, with a single veiy
long cilium.

C. olla (PI. 5. fig. 7).

The commonest form is that of a some-
what ovate cell 1-5000 to 1-2000" long,
sessile by the thick end on the outside of
the cell-wall of the plant it infests, and,
according to Braun and Cohn, sending fine
radical tubes into the interior ; the cell-
contimts of -the infested cell are usually
found disorganized and discoloured. In

CIBOTIUM.

[ 175 ]

CILIA.

anotlier form, distinguished by Priiigslieira
under the name of Pi/f/iium, the cells are
globular and occur in the infested cells,
pushing a long tubular neck out through
the ceil-wtdl. In both forms the contents
of the C/iri/(ridhan-ce\l are tinally resolved
into ciliated gonidia, which escape and
swim about. lu the external form, the cell
often opens by a lid (like the androspore
cells of G^DOGONiuJi); in the internal form
the slender neck opens at the end. Braun
has described no less than twenty -three of
these obscure bodies, while Eabenhorst
admits six species ; and they have been
observed by Cohn, who connects them with
Achh/a, considering them aquatic fimgi.
Carter has observed them in Spirof/t/ra ; and
we have found both forms in and on the
cells of Chlorosph.t'.ra. Braun and Cohn
declare them to be really foreign bodies,
that is, true parasites; but we are not clear
on this point ; they seem rather products
of diseased protoplasm, if they be not modi-
fications of the antheridial structures of
some of the Confervoids.

BiBi.. Al. Braun, Verjiinqunfj ^-c. (liai/
Trand. 1853, 185); Berl. Abhdndl. 1856,2
(plates) ; Ueb. CJuitridhim, Berlin, 1856 ;
Alff. Unicell. Gen. A"or. Leipsic, 1855 ; Bail,
Bot. Zeit. xiii. 678 ; Cienkowski, Bot. Zeit.
XV. 233 ; Carter, Attn. Nat. Hist. 2nd ser.
xvii. 101, and xix. 259 ; Barv & Woronin,
Ber. Geselkch. Freih. 18ti3 ; AYoronin, But.
Zeit. 1868, 81 ; Nowakowski, Cuhn, Biol, d,
Pfl.\. 1, ii.l877, 73, 201.

CIBOTIUM, Kaulfuss. — A genus of
Dicksoniese (Polypodiaceous Ferns) ; with
a bivalve indusium ; now made a subgenus
of Dicksonia.

BiBL. Hooker, 81/71. Fil. 49.

Fig. 127.

Cibotinm macrocari.um.
A pinnule with sori. Magnified 10 diameters.

CILIA (plural of ciliuvi) of Animals. —
These are microscopic filaments attached by
one end to the surfaces of various parts of
animals, and exhibiting a vibratory or rota-
tory motion. They are usuall}^ rounded and

broadest at the base, tapering towards the
free end ; sometimes they are flattened.
Their length is very variable, having been
estimated at 1-50,000 to 1-500" ; probably
1-15,000 to 1-500" would include most of
them ; in Bacterium termo they are
1-200,000" in diameter (Dallinger). The
larger size is attained by the cilia existing
on the point or angle of the giUs or branchial
laminse of the whelk {Buccinmn undatum).

Numerous examples of animals furnished
with cilia, showing their appearance when
at rest, are figured in Pis. 30, 31, 32, 43, &
44. During life, and for some time after
death, they are usually in constant motion,
giving the parts of the field of the micro-
scope in which they are situated a tremulous
appearance when their motion is very rapid
and the cilia are very minute. When they
are large, as on the gills of the common
sea-mussel (IMytilus), especially when
their motion is slackening, they are seen
waving to and fro, or lashing the water, and
producing in it strong currents, rendered
visible by the motion of minute particles
accidentally contained in the water. The
motion is mostly uniform, or in one direc-
tion ; occasionally, however, it has been
observed to cease for a moment, and then
to assume an opposite direction to that pre-
viously exhibited. During the motion, the
whole filament is usually more or less
cuned ; but in some instances among the
Infusoria, the basal portion of the cilia re-
mains rigid, whilst the terminal portion
vibrates ; under these circumstances the
cilia are distinguished as flagellifi>nu fila-
ments. Sometimes the cilia move around
an imaginary perpendicular axis, in a rota-
ting direction.

Cilia are found in all the Vertebrata, and
in the Invertebrata, excluding the Crustacea,
Arachnida, and Insecta. We have, on two
occasions, distinctly obtained cihated epithe-
lium, resembling that in PL 49. fig. 13, by
womidingthe bodies of the larva3 of garden-
moths ; but were unable to follow the obser-
vations. In Man; they spring from epithelial
cells ; the localities in which they are foimd
are stated under Epititeliltsi.

The uses of the cilia are of two kinds :
when the body to which they are attached
is of no great bulk or specific gi-avity com-
pared with that of the medium in which
they reside, the cilia become organs of loco-
motion, as in the Kotatoria, Infusoria, the
young AcalephjE, the ovum, &c. ; but if
the inertia of the body be too great to be

CILIA.

[ 1-G ]

CILIA.

overcome by the feeble power of the cilia,
tbey produce motion iu the surrounding
medium, as on the giUs of fishes, of young
reptiles, and of the Mollusca, tlie gill-tufls
of the Annulata, and the various mucous
surfaces of the Vertebrata upon whicli they
exist, in which they favour respiration and
excretion. liy the same agency they also
bring particles of food suspended iu the
medium towards the mouth. It need
scarcely be remarked, that the motion of
cilia must be stronger in one direction than
the other, otherwise there could be no
current.

The cause of the motion of cilia has long
formed a subject for discussion ; but it is
still unknown. In some instances, as in the
Infusoria, it appears to be voluntary. In
certain cases it might be attributed to the
action of a contractile amorphous tissue,
such as that composing the Amwb(e. It
would naturally be attributed to muscular
agency ; but no muscular tissue can be de-
tected : in fact, cilia are quite structureless ;
moreover they are often of less breadth than
the ultimate hbrillfe of muscle. Neither
the most powerful poisons, as strychnine,
prussic acid, opium and belladonna, nor
electricity, produce any elfect upon ciliary
motion, provided the structure upon which
the cilia are situated be not injured. It
also lasts a long time after death, having
been observed iu the lower aniirials nineteen
days after this occurrence, and when putre-
faction was far advanced. The question has
however, lost its interest in regard to its ne-
cessary dependence upon muscular action,
because cilia are common among the lower
plants, where this is out of the question.

The cilia and their motion may readily be
observed in the common Rotatoria and Infu-
soria, or iu a thin piece cut from the margin
of the gills of the oyster; or still better, the
sea-mussel ; in the latter they form a most
beautiful and interesting object. Fresh
water almost innnediately arrests the motion
of the cilia in marine animals. In some cases,
solution of potash excites the movement of
animal-cilia after it has become languid.

The detection of the cilia is fi-equently of
great importance, as the characters of Infu-
soria, &c. are often based upon their num-
ber and arrangement. The means are either
indirect — as by the addition of moistened
particles of colouring-matters, as indigo &c.,
to the living organisms, and watching for
the movements of the particles — or dircct,by
examining the structures after the addition

of solution of iodine, bichloride of mercury,
or of osmic acid, or drying them at a gentle
heat. Both methods should be adopted to
check each other: for molecular movement
has some resemblance to ciliary motion
when feeble, although there is absence of a
definite current ; and fine hair-like Algpe
or Fungi attached to aquatic organisms
often resemble cilia, but are deficient in the
motion.

See Infusoria ; Membranes, undu-
lating ; and Molecular motion.

BiBL. Purkiiije & \'alentin, Comm. Phys,
^•c. ; Sharpey, Todcfs Ci/cL of An. i^- Phi/s.
i. 606; Valentin, Wagner's Handto. Phys.
Si'c. i. 481 ; Yirchow, Archiv, vi. 133 ; Fn-
gelmann, Jen. Zeitschr. iv. 321 ; Roth,
Virchoiv's Arch, xxxvii. 184 ; Ilackel's
Biol. Stud. 147 ; Frey, Hist. 1876, 173.

CILIA of Vegetables. — These minute
vibratile threads, apparently of the same
(unknown) nature as those of animals, are
in all cases met Avith in connexion with the
protoplasmic or nitrogenous structures of
plants, the structure bearing the closest re-
lation to animal organizatiuu. Cilia have as
yet been found only in Flowerless Plants,
viz. in all the higher or stem - forming
Cryptogams, and in the Alga3 among the
Thallophytes. In the Marsileaceaj, Lyco-
podiacese. Ferns, Equisetaceae, Mosses, Ile-
paticae, and Characese, they are found upon
the active filaments (spermatozoids) dio-
charged from the antheridia. In the Algjfc
they occur upon the zoospores and some-
times upon the spermatozoids, and on the
fully-developed plants of the family Vol-
vocineas. They have been stated to occur
in certain other complete organisms, as iu
Closteriwn ; but this statement we believe '
to be erroneous. Rigid filaments bearing
some resemblance to cilia occur occasionally
upon Diatomacpte and Osciliatoriefe ; but
these are not vibratile organs. The mode
of arrangement, &c. varies considerably
among the cases above cited. In the sper-
matozoids of the Marsileacefe, Lycopodi-
acete, I'erns, and Equisetacei^, they are set
in considerable number along a filament
spirally or heliacally coiled (1*1. 40. tig. 34).
In the Muscacea), Ilepaticfe, and Characeoe,
a pair of very long cilia is attached at one
end of the filament (fig. 123, p. 162). In
zoospores, either they occur in a pair at
the apex, as in Prvtococcus, Conferva, Cla-
dophora, Cvdiuin, &c., or there are four iu
the same situation, as in Ulothrix, (Jhceto-
phora^ Ulva, &c. ; while the large zoospores
\

CILIARY,

[ 1T7 ]

CIMEX.

of (Edogonmm bear a crown of vibratile
cilia, aud the groat elliptical zoospore of
Vnucheria is clotlied with them over its
■whole surface. In the Volvocinea^, tliere is
a pair of cilia attached, just like those of
zoospores, to each niemher of the family of
which the compound organism is made up ;
and these project through orifices in the
common envelope, so as to render the per-
fect plant locomotive, while the cilia of
ordinary zoospores disappear when they be-
come encysted in a cellulose coat prepara-
tory to germination. The spermatozoids of
the Fucaceae, and the zoospores produced
in the sporangia of other Fucoids have a
different arrangement of the cilia : there
are always two ; but they are attached on
a reddish point on the side of the zoo-
spore, not at its apex, and one of the cilia
is directed forwards from the apex or beak,
while the other trails behind like a kind of
rudder.

The mode in which these transitory cilia
are lost is variously stated : some authors
think they are retracted into the protoplasm ;
from what we have seen, we believe they are
thrown off entire. The cilia have the same
chemical reactions as the protoplasmic sul)-
stance generally, and are apparently pro-
cesses of it; they are stained brown by
iodine, which also stops their motion and
renders them partly solid. The mode of
detecting and observing cilia is given in
the preceding article. Further particulars
of individual cases will be found under the
heads of the families and genera named above.

BiBL. Thuret, Zoospores cles Algues, ^-c,
Ann. cles Sc. Koi. 3 ser. xiv. & xvi. ; Anthe-
ridies des Fonc/eres, Ann. Sc. N. 3 ser. xi.
5 ; Hofmeister, Vergleich. Unfersuch. ^-c,
Leipsic, 1851 ; linger, Die Pfianze im Mo-
mente der TJiierwerdimg, 34, Vienna, 1843 ;
Al. Braun, Verjiinynng, 8(c. {jRay Soc. 1853) ;
Cohn, ProtococcKs pluvialis, Nova Acta A. L.
C. C. xxii. 735 {Bay Soc. 1853, 352) ; on
SfephanospJicsra, Siebold & Kolliker's
Zeitschr. iv. 77 {Ann. N. II. 2 ser. x. 321) ;
Henfrev {Ferns), Linn. Tr. xxi. ; Focke,
Physiol. Studien ; Sachs, Bot. 244.

CILIARY PROCESSES. See Eye.

CILTOPHRYS, Cienk.— A genus of
Actinophryina. C. infnsiomim, resembles
Act. sol, but is much smaller ; produces
swarm-germs ; in the scum of old infusions.
(Cit-nkowski. Schnitzels Arch. 1876, xii. 29.)

CIMEX, Linn. (Bug). — A genus of In-
sects, of the order Hemiptera, suborder
Heteroptera, and family Cimicid^e.

Char. Antenn.ie four- jointed ; labium
three-jointed, the basal joint the longest;
thorax subluiiate, not transversely divided ;
abdomen much depressed, and more or less
orbicular ; elytra reduced to a pah' of short,
transverse, scale-like pieces ; wings none ;
legs moderately long and slender ; tarsi
three-jointed.

C. lectularius (the bed-bug). Ferruginrms-
ochre ; thorax deeply emarginate, its sides
retlexed ; abdomen suborbiculate, acute at
the apex ; third joint of antenna3 longer
than the fourth ; rostrum inflected beneath
the thorax ; labrum short, broad, subovate,
trigonate and ciliated.

The common bug has only three setae,
one stouter than the rest, and not toothed
or serrated (PI. 33. fig. 27 a), and two others
extremely slender and very finely serrated
near the ends (PL 33. fig. 27 b) ; these are
about 1-20,000" in breadth at the sen-ated
portion (hence about the l-20th part of the
Ijreadth of the lancets of the flea). The
female is larger and more elongated than
the male. The offensive odour is due to a
liquid secreted by a pyriform reddish gland,
situated in the centre of the metathorax,
aud opening between the hind legs. The
eggs (PI. 39. fig. 20) are white, elongate-
o^-al, elegantly pitted, and terminated by a
lid, which breaks off" when the yoimg
escape. The latter are very small, white
and transparent, and have a much broader
head, with shorter and thicker antennae
than the mature insect. They undergo four
moultings, and are eleven weeks in attain-
ing their full size.

C. columliarius (Bug of the pigeon).
Ferruginous-ochre ; thorax deeply emar-
ginate, sides reflexed ; abdomen orbicular,
subacute at the apex ; third joint of an-
tennre slightly longer than the fourth ;
length about 1-5".

C. hinmdinis (Bug of the swallow).
Fusco-ferruginous ; thorax slightly emargi-
nate ; sides flat ; abdomen ovate, subacute
at apex ; antennae s'hort, tliird aud fourth
joints nearly equal; length about 1-7".
Found in swallows' nests.

C. jripisfrelli (Bug of the bat). Ferrugi-
nuus-ochre, shining ; thorax deeply emar-
ginate, sides slightly reflexed ; abdomen
ovate, posteriorly attenuate ; third joint of
antennae longer than the fourth ; length
1-6". On the common bat.

Megnin maintains that these all belong
to C. lectularius.

BiBL. De Geer, Mem. iii. ; Dumeril,

CINCHONINE.

[ 178 ]

CIEEIPEDIA.

Cons. yen. s, I. Ins. ; Westwood, Infr. ;
id. Br'if. Cijd. N. II. i. 640 ; Jenyns, Ann.
N. H. 1839, iii. 241 ; Curtis, Brit. Entom.
xii. 569 ; Landois, Sieh. (^ KiiU. Zeitschr.
1868 {Anat.) {Qu. Mic. Jn. 1868, 208);
Megnin, Parasites, 1880, 53 ; Leidy, Jn.
ilf/c. &r. 1878, i. 27.

CIN'CIIONINE. Cinclioniiie is insoluble
in etlier. See Alkaloids.

BiBL. See Chemistry.

CINCLID'IUM, Swartz.— A genus of
Mniacefe (operculate Mosses, arranged
among the Acrocarpi from prevailing liaLit);
of -which one species, C. stygium, has been
found in Yorkshire.

BiBL. Wilson, Bryol. Brit. 260 ; Berke-
ley, Brit. Moss. 181.

'CINCLIBO'TUS, P. de B. See Guem-

BELIA.

CINNAMON.— This consists of the inner
part of the bark of Cinnamomum Zeyhmi~
aitn (Lauracese) ; that of Cassia (C. Cassia),
a coarser and less aromatic substance, is
often substituted. These both consist of
pitted liber-cells andoil-beariiigpareuchyma
containing starch-granules, and are scarcely
distinguishable by the microscope. This
instrument, however, enables us to detect
the fraudulent extraction of the aromatic
oil, since heat applied for this purpose dis-
torts and destroys the characters of the
starch-gi'anules. Ground Cinnamon and
Cassia are adulterated with flours of dift'erent
kinds, to increase bulk ; these are detected
bv the characters of their starch-granules.
' BiBL. Hassall, Food ^-c. 399.
CIONIS'TES, S. T. ^^'rigllt.— A genus of
Ilydroid Polypes, fam. Podocorynidfe.
C. reticulata.

BiBL. Hincks, 5n'^. Zooph. 134; "VYi-ight,
Aim. N. H. 1861, viii. 123 (fig. 1).

CIRCULAR CRYSTALS.— This term
has been applied to the flattened groups
of radiating crystalline needles formed by
many salts and other crystalline substances.
The term, however, is objectionable as
tending to obscure their true nature. They
form beautiful polarizing objects. Among
the most interesting may be mentioned
boracic acid, oxidurate of ammonia, sali-
ciue, and sul])hate of cadn)ium. They
are further noticed under their respective
heads. Some of them are figured in PI. 39.
flgs. 9-12.

It is interesting to remark that some
of these circular crystals, as boracic acid,
although belonging to a biaxial system, yet
exhibit a single series of coloured rings.

See Ammonia, OxALtrRAXE of, and Po-

LARIZATIOX.

BiBL. Brewster. Optics, 1853, 269.

CIRCULATION in Animals. — The
movement in a temporarily or permanently
definite to-and-fro direction, of the nutritive
liquids of animals. We can only enumerate
here the articles in which will be found a
notice of the circulation, whether true or
spurious, as occurring in the most easily
accessible or interesting organisms ; suffice
it to say that circulation is produced either
by the agency of muscular or other con-
tractile tissue, or by the action of cilia.
AsELLUs, Aeachnida, Entomostraca,
Infusoria, Insects (Coccinella, Ephe-
mera, LARViE, LiBELLULID-S;), RaNA,

Triton.

CIRCULATION in Plants. See Ro-
tation and Latex.

CIRRIPE'DL\ or CIRRHOPODA.—
An order of Crustacea. The barnacles or
acorn-shells.

Char. Marine animals, in the adult state
attached to other bodies ; enclosed in a mul-
tivalved shell or in a coriaceous involucre
furnished with calcareous points, the rudi-
ments of a shell ; eyes none in the adidt
state ; six pairs of legs, each with a short
fleshy peduncle, and two many -jointed
horny cirri ; mouth furnished with mem-
branoso-corneous mandibles and maxilla? ;
tail terete, acuminate, reflexed between the
legs ; body npt divided into segments,
although there are indicatit ns of them in
the form of transAerse furroA\s on the dor-
sal surface. The six pairs of arms or legs
which are situated on the ventral surface
have each, supported on a short peduncle,
two long thin incurved filaments, consist-
ing of numerous joints, and covered with
hairs. The animals protrude these flla-
ments incessantly from the orifice of the
shell, and retract them, whereby water for
respiration and, with the water, food is
brought into the shell. Cirripeds are
usually hermaphrodite ; sometimes dice-
cious.

The yomig Cirripeds, after loavinp' the
ovum, resemble some of the Entomof-trata,
as Cyclops ^ Cypris (Nauj>liiis-fonn) . They
are unattached, and possess eyes.

BiBL. Cuvier, Man. Mus. d'lIi.Ht. Kat.
1815, ii. ; Saint-Ange, Mem. Cirrij}. ; Cold-
stream, Todd's Cyclop., . art. CirrJiopoda ;
liurmeister, liankcvfusser : J. Y. Thompson,
Zool. Bescarchcs, and Bhil. Trans. 18:;5,
355 ; Darwin, Monoij. Cirripedia {Bay »S'o-

CLADINA.

[ 170 ]

CLADOPTIORA.

cieti/) ; Nicholson, Zool. 1878, 271 ; and the
Bihl. of AxufAL KixGDOjr.

C'LAUI'NA, Nyl.— A subgenus of Cla-
donia.

C. si/lvrifica, amaju-ocrcea, rancjiferina,
and unriaiis, with their varieties, occur in
Great Britain.

BiBL. Leighton, Lich.-Fl. G. B. m.

CLADOBOT'HYUM, Nees. See Dac-

TYLIUM.

CLADO'DEI. — A series of Lichens (fam.
Lichenacei), comprising the tribes Bseomy-
cei, Cladoiiiei, and Stereocanlei.

CLADO'DIUM, Brid.— A synonym of
some species of Bkyum.

CLADOGRAM'MA, Ehr.— A genus of
Diatomaceae.

Char. Frustules disk-shaped, valves con-
vex, with radiating irreguhirly forked lines ;
connecting-zone ring-like.

C. caUformcum, Ehr. (PI. 51. fig. 14).
C. conifum, Grev. Barbadoes deposit.

BiBL. Elirenberg, Mikrog. pi. 33 ; Gre-
ville, Mic. Trans. 186-5, 97.

CLADO'MOXAS, Stein.— A genus of
Flagellate Infusoria.

Char. Bodies ovate, with two equal an-
terior flagella, inserted in ends of a branched
tubular zoary.

C. fruticidnsa, fresh water.

BiBL. Kent, Infus. 284.

CLADONE'MA, Duj.— A genus of Hy-
droid Polypes, fam. Stauiidiiclse.

C. radiatum. Devonshire coast.

BiBL. Hincks, Brit. Zooph. 61 ; Gosse,
Dev. Coast, 257.

CLADONE'MA, Kt.— A genus of Fla-
gellate Infusoria.

Char. Bodies p^oiform, oblique in front,
attached to a branched pedicle ; flagella
1 long and 1 short, lateral.

C. la.xa. Fresh water ; on Myriophyllum.

BiBL. Kent, Infus. 264.

CLADO'NIA, Fee.— A genus of Liche-
naceous Lichens, with a somewhat shrubby
thallus, and fistular podetia, abundant on
moors and heaths. It comprises the sub-
genera PycnothiUa and Cladina. The Rein-
deer Moss (C. rancfiferina) is common in
such localities. 26 other British species.

BiBL. Hook. Brit. Fl. ii. pt. 1. 238 ; Eiu/l.
Bot. pi. 173, 174, &c. ; Leighton, Lich.-Fl.
G. B. 52.

CLADONIE'L— A tribe of Lichenaceous
Lichens, series Cladodei.

Gen. Chidonia and Pilophoron.

CLADOl'HORA, Kiitz.— A genus of
Confervacea; (Confervoid Algae), distin-

guished by the branched habit of the at-
tached filaments. The CladopharcB are in-
teresting in many respects, in particular for
the thick laminated structure of the cell-
wall, the special projecting orifice in this by
which the zoospores are discharged, the
large number of the zoospores, and, lastly,
by the favourable opportunity they afford
of observing cell-division in the groAvth of
the branched filaments. The filaments are
composed of cylindrical cells attached end
to end, from which the branches arise by
the gradual protrusion of a cylindrical pouch
near the upper end, Avhich' pouch, becoming
shut off by a septum, forms the first cell of
the brancli. The cellulose wall acquires
repeated layers of thickening with age ; and
longitudinal and transverse strife may be
detected in these by careful management.
(See Spiral Structures.) The cellulose
wall is lined by a layer of protoplasm (pri-
mordial utricle), upon the inside of which
lies the chlorophyll, not, however, really
imbedded in it, as it is often seen retracted
from it in the centre of the cell. At certain
periods, numerous starch-granules occur in
the mass of chlorophyll ; but these disappear
when the latter is about to subdivide into
zoospores. When this takes place, the whole
mass of chlorophyll is contracted from the
wall, and becomes broken up, by a kind of
segmentation, into a very large number of
2- sometimes 4-cihated zoospores (these
sometimes occur in paii's, through imperfect
division). The zoospores, which are pro-
duced in all the cells, are discharged through
a special papilliform orifice in the cell-wall
(PI. 9. fig. 13) ; they have a distinct red
spot. Numerous supposed species inhabit
fresh, brackish, or sea-water in Britain ;
some are veiy common and abiuidant ; but
it is difticidt to draw out difterential cha-
racters, as the habit appears to be A"ery
variable. They are Conferva of older
authors.

C. ylomerata, DiUw., is of a dark green
colour, and grows commonly in long drawn-
out skeins, in pure running water ; but it
seems to be identical with the rarer C. cega-
gropila, L., which forms dense balls 2 to 4"
in diameter, in lakes ; while there is also a
marine variety.

C. crispata, Sm., is perhaps not distinct ;
it forms yellowish or dull green strata,
everywhere common in fresh water ; fre-
quent in brackish water. It is the same as
C.Jlarescens, Both. C. fracta, Fl. Dan., is
probably a form of this.

n2

CLADOPHYTUM.

[ 180 ]

OLATimOCYSTIS.

The commonest marine species, whicli are
often found in large quantities on the sea-
shore, remarkable by their bi ight green tint,
are C. rupestris, L., Icetevirens, l)ilhv., al-
bida, Huds., Icmosa, Roth, arcta, Dilhv., and
glaucescens, Griff. ; but some of these, and of
the rarer, appear doubtful. The species re-
quire a careful study of fresh specimens in
all stages. Kiitzing {Sp. Alg.) has made an
inextricable mass of confusion of his species.
Eabenhorst admits 8 species, with nume-
rous varieties.

BiBL. Hassall, Aly. 213, pi. 65-67 ;
Harvey, Mar. Alc/ce, 199, pi. 24 D ;
Tliuret, Rech. sur les Zoosp. Sfc, Ann. Sc.
Nat. 3 ser. vol. xiv. 10, pi. 16; Al. Braun,
Verjungung, c^-c. {Ray Soc. 1853) ; Mohl,
Vermischte Schrifteti, 362, pi. 13 ; Raben-
horst, Flm: Ah/.' iii. 333.

CLADOPH'YTUM, Leidy. — Probably
the mycelium of a fungus. Found in the
intestine of a lulus.

BiBL. See Aethromitus.
CLADOSPO'RIUM, Link.— A genus of
Dematiei (Hyphomycetous Fungi j, stated
by Tulasne to be conidiiferous forms of
Sphseriacei. CI. herharuni is one of the
commonest moulds ; it spreads over the
surface as a dense or loose web of con-
fluent tufts of microscopic filaments, straight
or ciu-ved, more or less varicose, simple or
branched ; from these arise chains of spores,
simple or with one or more septa, round,
oval, or longish according to age, and finally
becoming detached from one another.

CI. herharum, Lk. Tufts effused, at first
green, then black ; spores olive ; very vari-
able in habit. Everywhere common on
decaying substances. Corda, Ic. Fung. iii.
pi. 1. fig. 24; Fresenius, JJei^r. zur Myk.
pi. 3. fig. 29 ; Dematmm articulatum, Sow-
erby, t. 400. fig. 8.

Cl. dendriticum, Wallr. On leaves of
pear-trees and hawthorn. C, pi/roi-um,
Berk. Gardn. Chron. 1848, 398. 'Hchmn-
thospo)-ium 2>.'/''"'""''>^i Desmaz. No. 1051.
C. orhiculalwn, Desm. Ann. iSc. Nat, 3 ser.
275.

Cl. depressum, Berk. & Br. On living
leaves of Angelica. Ann. If. II. 2 ser.
vii. 97, pi. 5. fig. 8.

Cl. hrachormium, Berk. & Br. On leaves
of Fumitory. Ibid.

Cl. ligincohnn, Covda. On dead wood.
Corda, Icon. Fang. i. pi. 3. fig. 206.

Cl. nodulosmn, Corda. On stems of herbs.
Corda, lam. Vang. i. ])1. 4. fig. 212.

Ectocarpaceae (Fucoid Algae), containing
two common British species, C. verticillatus
and C. spongiosus, which grow on rocks and
stones, and form olive tufts a few inches
high, composed of rigid irregularly branched
cellular axes, clothed by whorls of short,
mostly simple, articulated branches. Harvey
states that the summer branches contain
dark grains in their withered tips, and are
deciduous, being replaced in winter by
othei-s which bear numerous lateral stalked
spores. It is probable that these represent
respectively the trichosporangia and oospo-
rangia found in Ectocarpus, and that the
so-called 'spores' emit zoospores. See

Alg. pi. 9 A ;

Fig,

ECTOCAEPUS.

BiBL. Harvey, Br. Mar.
Phyc. Brit. pi. 33 and 138.

CLADOT'RICHUM, Corda.— A genus of
Dematiei (Hyphomycetous Fungi), forming
dark flocculent points, or
confluent into powdery
strata, on dead stumps, kc.
The mycelium consists of
rigid, much-branched, sep-
tate filaments, the upper
j oiuts swollen ; the spores
in chains together at the
ends of branches, and bi-,
triseptate, constricted in
the middle.

The species are pro-
bably states of Ascomyce-
tous Fungi.

Cl. triseptatum, Berk,
and Broome. Spoi^es ob-
long, very obtuse, with

Cladotrichum

polysporuiu.

Magn. 200 diam.

CLADOS'TEiaiUS, Ag.

-A genus

of

three septa, and constric-
ted opposite the middle
septum. Ann. Nat. Hist. ser. 2, vii. p. 98,
pi. 5. fig. 7. On a dead stump.

C. polysporum, Corda (fig. 128). Spores
biseptate. Corda, Icon. Fung. iv. pi. 6. fig.
83 ; Frachtflora Fur. Schinwulbild. {I'oly-
thrincium, Fries, Sunim. Vcg.)

CLATIIROCYS'TIS, Henfrey.— A ge-
nus of Pabuellaceous Algae, founded on
Microct/stis (Pulycystis) ceruginosa of Kiitz-
ing. (PI. 5. fig. 9.) The plants occur in
autumn in myriads in freshwater ponds,
giving the water a rich grass-green tint ;
the colour when dry is that of verdigris.
Their appearance to the naked eye is that
of a mass of green granules suspended in a
colourless liquid. Under the microscope
each granule is found to be a gelatinous
body 1-50 to 1-15" in diameter, in which
ai'e imbedded an infinite number of green

CLATriRITLINA.

[ 181 ]

CLAVICErS.

cells about 1-8000" in diameter. Tlie gela-
tinous masses expand by tlie nudtiplication
of the green cells in the peripheral stratum,
so that they become hollow sacs, the walls
of which burst at various points and pro-
duce a clathrate structure. Tlit- processes
of tl}e network ultimately break asunder
and commence a new development of the
same kind.

BiBL. Henfrev, Mic. Trans, new ser. iv.
53, pi. 4. figs. 2S-3G; Currev, Mic. Ja.
vi. 215 ; Klitz. Tab. Phyc. i. pi. 8 ; Duncan,
Jn. Mic. Soc. 1880, iii. iz.

CLATIIRULINA, Cien.— A genus of
Actin(iphryiua = a stalked Actinopknjs con-
tained in a fenestrated glnbularor pvriform
carapace. The pseudopodia project through
the lenestrae.

'2 species or varieties.

BiBL. Cienkowski, ArcJiiv f. mik. Anat.
iii. p. 311 ; Qu. Mic. Jn. 1868, p. 31.

CLATHRUS, Mich.— A genus of Gaste-
romycetous Fungi, fam. Phalloidei.

C. cnnceUatus, fig. 273.

CLAVA, Gm. — A genus of marine Hy-
droid Polypes, fam. Cla^-idfe.

6 British species j height \ to 1^".

C. mulficornis. Rose-coloured, mouth
white ; \\'' high. Common on stones be-
tween tide-marks.

BiBL. Hincks, i?;7V. Zooph. p. 1.

CLAVATELLA, Hiucks.— A genus of
Hydi'oid Polypes, fam. Clavatellidae.

C. prolifera, British.

BiBL. ilincks, Brit. Zooph. 70.

CLAVATELLIB.E.— A family of Hy-
droid Polypes. 1 genus, Clavatella.

BiBL. Hincks, Brit. Zooph. G9.

CL A VA'TI. — A family of Hymenomyce-
tous Fungi, characterized by bearing basi-
diospores covering the tip and sides of
branched or simple club-sha2)ed or variously
cylindrical, compressed, or foliaceous re-
ceptacles. See Basidiospobes, Hymeno-

MYCETES.

CLAVELI'XA, Sav.— A genus of Tuni-
cate MoUusca, of the family Clavelinidre,
imder which head the characters are given.

C. lepadiformis. Thorax a third of the
length of the body, lines yellow; length
\ to I". On rocks and stones at low water.

C. prodiicta. — Thorax very short, as broad
as long, abdomen very long.

C. pumilio. Nearly sessile and square.

Bibl. That of the family.

CLAVELI'XID.E.— A'family of Tuni-
cate Mollusca.

Distinguished by the separate bodies

arising from a common creeping root-like
fibre, and the mantle being united to the
test at the orifices only.

These animals are very transparent, and
well calculated for the study of the internal
structure of the order. Genera :

Clavelina.

Bodies ()bL)ng, erect; bran-

chial and anal orifices without rays; thorax
marked with coloured lines.

Perophora. Bodies rt)uudish, compressed ;
thorax not marked with coloured lines.

BiBL. Forbes and WaiAqj ,Brit.Mollusca,
i. 25 ; Goose, Mar. Zool. i. 135; Lister, Phil.
Trans. 1834 ; M.-Edwards, Ascid. Comp.

CLA'VIPES, Tulasne. — A genus of
SpluTriacei (Ascomycetous Fungi), con-
taiiiiug the plants which produce the enjot
of rye and other grasses. These plants have
recently been extricated from great confu-
sion by Tulasne, who appears to have placed
their history on a satisfactory basis.

The first sign of the attack upon the
flower of a grass is the appearance of a
white mould, sometimes accompanied bj' a
honey-like secretion, consisting of minute
cells, somewhat after the fashion of the
yeast-plant ; a swelHug (sphacelia) then
takes place upon the outside of the nascent
pistil, which extends to the outer part of
the substance of the wall of the ovary,
growing with this until it forms a fungoid
mass of the same shape as an ovary, but
obliterating the cavity of the latter. At
this time it is soft, white, grooved on the
surface, and excavated by irregular cavities,
which are connected with the external folds
or grooves ; the surfaces of these are all
covered with parallel linear cells, like anhy-
menium ; and from the extremities of these
ai-ise elongated ellipsoid or oval cells, about
1-5000' ' in length. These become detached,
and, when they are placed in water, germi-
nate and emit filaments. These bodies are
spermatia, sti/lospores, or perhaps conidia :
the}' exhibit no motion in water, although
they resemble the spermatia of some other
fungi. At this time Tulasne calls the struc-
ture a spermogonium. At a certain epoch a
viscid fluid exudes from the sphacelia, flow-
ing over it and carrying about multitudes
of the spermatia or stylospores (PI. 26. fig.
1 7) ; but previously tO this, a solid body, of
a violet colour on the surface and white
within, has originated at the base of the
spermof/oniinn, and it gradually grows and
rises out of the pale;B of the flowers, form-
ing the spur or ergot. This is not a meta-
morphosed seed, residting from diseased

CLAVID.E.

[ 18:2 ]

CLIMACONEIS.

conditions, but a real new fungoid structure,
the Sclerotiimi of DC. and others. When
this e>yot is sown in the earth like a seed,
it produces a number of little pedicles sur-
mounted by thickened heads, repesenting
stalked Sph(en(B (PI. 26. fig. 18) ; and on
these heads are ultimately found fine points,
which indicate the ostioles of little coucep-
tacles (fig. 19). The walls of these concep-
tacles are lined with asci of elongate clavate
form (figs. 20, 21), with linear, slightly
clavate paraphyses. These bodies are the
Sphceria purpurea of Fries, System. Myc.

Our space does not admit of fui-ther de-
tails ; but it must be noted that very varied
opinions have hitherto prevailed as to the
nature of Ergot. Smith and E. Quekett,
as also Leveille, Phoebus, Mougeot, and
Fee, regarded the ergot as a mere diseased
form of the seed, associated with a parasitic
Fungus {Sphacelia, Lev., Fee ; Eryotcetia,
Quekett).

The sphacelia is often accompanied by a
Mucedinous fungus, wliich is certainly not
the result of germination of tlie stylospores
as might be imagined, but a distinct plant.

Tulasne describes three species :

C. purpurea, Tul. (PI. m. figs. 18-22).
The ergot of grasses := SpJueria entomur-
rhiza, Schum. ; Sphceria (^Cordyceps) pur-
purea, Fries ; Kentrosporium mitrotmn,
Wallr. ; Sphcerojms funyorum, Guibouvt :
Cordyliceps purpurea, Tulasne. On the
flowers of Grasses, such as rye, wheat, oats,
and numerous pasture grasses.

C. microcephala, Tul. Kentrosporium
mierocephaluin A\ allr. ; Sphceria microcc-
phala, AN'allr. ; Sphceria arms, Trog. ; Cordy-
ceps purpurea, var. ucus, Desm. On Pliruy-
mites communis and Molinia ccerulea.

C. niyricans, Tul. On species of Scirpus.

BiBL. Tulasne, Ann. des Sc. Nat. 3 ser.
XX. 5-43, pis. 1-4, where all the previous
literature is reviewed ; Quekett, Li7in. Tr.
1839; Cesati, i?,.^. Zeit. 185o, 74; Currey,
Qu. Mic. Jn. 132; Konorden, Bot. Zeit.
1858, 97 ; Lindley, Vey. Kinyd. ; IvUlm,
Mitt, landw. Inst. Halle, i. 18G3 ; Sachs,
Bot. 381.

CLA'VID.E. — A family of Hydroid
Polypes.

C]iar. Polypes clavifomi or fusiform, with
scattered tentaeula. Genera :

Polypes stalked.

Stem simple Tubiclava.

Stem niuoh branched Cordylopkora.

Polypes sessile.

Tcntncles few Tiirris.

Tentacles very numerous ... Clava.

BiBL. Ilincks, Hi/dr. Zooph. p. 1.
CLAYULA'RIA, Grev.— A genus of
Diatomacese.

Chor. Frustules free, linear, with nu-
merous transverse pseudo-dissepiments, in-
terrupted by a central smooth external
plate. Valves with a central inflation, and
a longitudinal row of short subcapitate
processes.

C. barhadensis (PI. 51. fig. 33). In Bar-
badoes deposit.

BiBL. Greville, Micr. Trans. 1865, p. 24.
CLAVULI'NA, D'Orb. — A modified
Vcdvulina, in which the triserial arrange-
ment of the chambers (three in one whorl
of the spire) has passed into a uniserial or
linear row, making altogether a claviform
shell.

The long dimorphous Textularice, having
a similar shape, liave been recorded as Cla-
vulince ; but the absence of the septal vcdve
distinguishes them.

C. parisie?isis (PI. 23. fig. 51.) is a neat
form, with a marked distinction of triserial
and uniserial growth. These long dimor-
phous Valndince are common in some
Tertiary deposits, and in the Indian and
Australian seas.

BiBL. Parker and Jones, Ann. N. H.
ser. 3, V. 467-469; Carpenter, For. 147,
193.

CLEISTOCAR'PI, (Closed-fruited, i. e.
inoperculate). — An artificial division of the
Mosses.

In this group, the capsule bursts irregu-
larly. It contains the families Bruchiacese,
Phascacefe, and Ephemerefe.
See Mo-ssES.

CLETO'DES,Brady.— A genus of Cope-
poda (Entomostraca). 4 species. In di'edg-
ings on the north British coasts.
BiBL. Brady, Copepoda {Bay Soc.).
CLIMAC AM'MINA, Brady.— An arena-
ceous, coarse Textularian Foraminifer, of
bigeuerine growth; with labyrinthic struc-
ture inside the chambers, and cribriform
aperture. Fossil in the Mountain-limestone
of P)ritain and Russia ; not rare.

BiBL. IT. B. Bradv, Monoy.Carb. ForatJi.,
Pal. Soc. 1876, 67. '

CLIMA'CIUM, W. and Mohr.— A genus
of Mosses, synonymous with Ilypnum (den-
droides).

BiBL. Wilson, Bryol.Brit. p. 325 ; Berke-
ley, Brit. Moss. p. 140.

CLIMACONEIS, Grun.— A genus of
UiatomacefB.

Char. Frustules bacillar, free (?), with

CLIMACOSniEXIA.

[ la-^ ]

CLOSTERIUM,

2 ."calariform dissepiments ; valves striato-
puuotatc^, costoe none.

C. Lorenzii. Yahes linear-lanceolate,
swollen at the ends and the middle. In the
Adriatic.

BiBL. Grimow, Wien. Verhandl. 18G2,
421, pi. 8. fiff. 7.

CLLMACbSPHE'NIA, Ehi-.— A genus
of Diatomaceoe.

Char. Frustules cuneate, stipitate, di-
vided into loculi by transverse septa ; valves
obovato-lanceolate, vrith moniliform vittae
in the front view. Marine ; not British.

C. australis. Very shortly stipitate ; sides
of the valves not (very faintly ?) striated.

On Algce from New Holland and South
Africa.

C. monilicjera (PI. 25. fig. 9). Stipitate,
sides of tlie valves transversely striated {a,
front view ; b, side view).

In the Gulf of Mexico.

Rabenhorst enumerates 6 species.

BiBL. Ehrenb. Abh. Berl Ak. 1841, 401 :
id. Ber. 1843 ; Kiitzing, BaciUar. 123, and
Sp.Alq. 114; Rabenhorst, Alg. i. 299.

CLIMACOS'TOMUM, Stein, = S^nrodo-
miim virens, Ehr.

CLI'OXA, Gi"ant. — A genus of marine
Sponges. By means of the spicula imbedded
in their surface, they burrow into rocks,
shells, and stones.

BiBL. Gosse, Mar. Zool. i. 5 ; Hancock,
Ann. Nat. Hist. 1849, i. 321 ; Bowerbank,
Brit. Spoq. ii. p. 212.

CLONOS'TACHYS, Oorda.— Agenus of
Mucedines (Hyphomycetous Fungi), appa-
rently not distinct from Botrytis.

C. araucaria (fig. 347) has been found in
Enirland.

BiBL, Corda, Prachffl. europ. Schimmel-
bi/cl pi. lo ; Currey, Qu. Mic. Jn. v. 126.

CLOSTE'RIUM, Nitzsch.— A genus of
Desmidiacea? (Confervoid Algae).

Char. CeUs single, elongated, attenuated
towards each end, entire ; mostly curved
Innately or arcuate ; junction of the seg-
ments marked by a pale transverse baud.
Endochrome green.

This beautiful genus is of great interest to
the scientific microscopic observer. Many
of the species are veiy common, so that
scarcely a drop can be taken from the bot-
tom of a clear pool without some of them
being contained in it.

Each cell is composed of two equal por-
tions, uniting at a transverse line occupying
the middle of the cell. The endochrome
exhibits longitudinal bands (PL 14. fig. 40),

the number varying in different species, of
a darker green thau the rest of the endo-
chrome (PL 14. figs. 40, 41, 43). A num-
ber of chloropliyll-vesicles are frequently
visible in the endochrome, sometimes scat-
tered irregularly, at others arranged in lon-
gitudinal series (PL 14. fig. 43) ; at certain
periods these contain starch-granules.

The green endochrome is separated from
the cell-wall by a stratum of colourless pro-
toplasm which occupies a bluntly triangular
space at each extremity. In many cases
the protoplasm at these ends exhibits a
large roundish vacuole, in which a number
of minute granules are contained, often in
active motion. Similar granules are visible
in the marginal line of protoplasm, which
exhibits a distinct circulation, requiring a
power of about 403 to show it clearly.
Focke, Osborne, and others have described
cilia inside the cell-wall, and attributed the
circulation to their action ; but this is erro-
neous. The protoplasm appears to flow up
over the interior of the cell-wall on all
sides, from the centre to the extremity,
then to turn round past the vacuole, and
return over the surface of the green endo-
chrome parallel to the upward course.
Wills states that the vacuoles at the ends
of the cells are contractile vesicles, con-
nected with the flow of the currents.

The Closteria are reproduced in various
ways. The individuals divide, like the re.-t
of the Desmidiacese, the separation taking
place transversely in the situation of the
transparent space, where two new half-cells
become developed, subsequently separating.
As tliese new ' halves' are often very small
at the epoch of separation, specimens occur
with the two portions very unequal.

Another mode of reproduction is by con-
jugation. In this, a pair of individuals be-
come united somewhat in the same way as
in the Zygnemaceoe ; ordinarily the indi-
viduals conjugate by the convex side. The
process is this : — The outer membranes of
the parents split circularly in the situation
of the central transverse space ; a delicate
internal membrane is protruded from each
as a sac, and these meet and coalesce.
Sometimes the sacs are in paii's from each
parent-cell. (See Conjugation.) When
the cross process is complete, the contents
of both parent-cells pass into it and become
collected iuto a globular or squarish cell or
zygospore (PL 14. tigs. 42 & 46.). Dif-
ferent statements are made with regard
to the ultimate history of this; and it is

CLOSTERimi.

[ l'^4 ]

CLOSTERIUM.

probably variable. Morren states that it
becomes a moving gonidium, while most
authors state that it becomes a restiug-spore
with lirm membranous coats. Again, Mor-
ren assumes the segmentation of the green
contents of this spore or gonidium into a
number of portions, each of which becomes
a perfect individual. Focke gives a figure
which seems to bear out this statement ;
and it would find an analogy in the mode
of reproduction by active gonidia in Pedi-
astrum, described by Caspary and Brauu.
(See Pediastrum.) Focke also figures a
cov^diiionoiClosterium Lunula, in which the
whole of the green contents of an individual
cell had become retracted from the walls,
and converted into a number of green glo-
bular bodies, with proper coats, resembling
the resting spores found under certain con-
ditions in many filamentous Algse. (See
OEbogonium and Spuiogyea.)

The Cloden'a are capable of fixing them-
selves by one extremity to foreign bodies,
and Ehrenberg asserted the existence of a
foot-like organ ; but no such structure seems
to exist. The individuals also possess a
power of moving in water, but the nature
of this is inexplicable at present. The seg-
ments of the outer membrane separate from
each other when their contents decay, and
often when they are dried. The membrane is
coloured blue hj sulphuric acid and iodine
(cellulose) ; in its natural condition it often
has a reddish tint, especially towards the
ends.

Rabonhorst describes 52 species, with
numerous varieties.

Analysis of ordinary British species : —

( Cell suddenly narrowed at the ends J at fen uatum,

1, ' into a conical point \ 1.1-57".

I Cell not suddenly narrowed 2

"Cell striated, tapering into a beak
at ends, lower margin prominent

at middle 3

Cell very minute, beaked, straight, i Griffilkii*,
"[ not striated, nor lower margin - 1. l-oOO to

prominent at middle ( l-4oU".

I Cell not beaked ; if striated, lower
L margin not prominent at middle 6

i Beaks setaceous, as long as or lon-
ger than body 4
Beaks linear, much shorter than

( Beaks much longer than body |j ^.n^jir

\ Beaks about as long as body

( ros/ra/um,
•")!. 1-169".
C Cells much inflated at middle, j lialfsii, ^^

I rapidlv tapering at ends ( 1.1-79".

1 Cells slightly inllated at middle, ( Jinealuin,
I gradually tapering at ends ^ 1.1-48".

7.

10.

11.

12

13.

(

14

15,

* PI. II. figs. 57 & 58.

t 1*1. 14. figs. 45 & 4t> (Conjugation).

^Cell minute, acicular; sporangium

; cruciform 7

J Cell not acicular ; sijorangium or-
V. bicular 8

(Ends obtuse < j yl\iQii

1 T-, , , i acutum,

f iinds acute •< j^ 1-177"

/Cell semilunate or semilanceolate,
I lower margin inclined upwards

-( at ends 9

Cell with either truncate ends, or
lower margin inclined down-
wards at ends 12

J Vesicles numerous, scattered •< , itjo"

( Vesicles in a longitudinal row 10

J Ends of cell slightly curved up- i tiirgidum,
J wards ; longituoiual strise distinct ( 1.1-39".
"i Ends of cell straight; striae none

V or indistinct 11

I Cell linear-lanceolate ; ends coni- j aeerosum t,

; cal, obtuse 1 1. 1-70 to 1-58".

) Cell semilanceolate; ends auh- \ lanceolatum,

y. acute I 1.1-64".

i Cell not striated, crescent-shaped 13

^ Cell either not crescent-shaped, or

I else distinctly striated 17

j" Vesicles numerous, scattered -5 I'^l'.tiS'^"'

^ Vesiclesin longitudinal row 14

' Empty cell colourless, ends round-

ed.. 15

Empty cell usually reddish, ends
subacate 16

! Lower margin of cell inflated at j moniliJerumX,
middle 1 1. 1-70 to 1-60".
Cell not inflated at midtUe < *" " -')so"

(Cell inflated at middle l 1 T-9U to 1-60".

( Cell slender, notinflated at middle^ "^r'l^l^O"
/ Lower margin of cell inclined up- j ^ij /,^^^ ^
wards at truncate ends; longitu- J 1 i.h-''
dinal striae none or indistinct ... [ ' " '' •
Ends of cell inclined downwards ;

stria" distinct 18

I Longitudinal striso to 7,prominent 19
( Longitudinal stri« numerous, fine 20

rCell semiluna or crescent-shaped -j '^"^ " "75'"

"( i angiistuhim,

(Celllmear -^ j. i.^q".

(Cell narrowly linear, nearly Sjiineidion,

) straight :. n-69 to 1-111".

I Cell tapering, curved 21

.'Longitudinal stria; crowded, 8U- * s/ri'oZn/iini,

j turcslto3.. ■) 1.1-80 to 1-68".

■^ Longitudinal striae not crowded ( intermedium,
\ sutures usually more than 3 "i 1. 1-77 to 1-54".

BiBL. Meneghini, Syn. Desmid.,Linncpa,
xiv. 201 ; Ehrenb. Infus. ; Ralfs, Brit.
Dcsjnidiexe ; Smith, Ann. N. H. 1850, v. 1 ;
Brebisson, Ahf. Fidaise, e^'- Conjiujaice ; Kiit-
zing, Spec. A/c/. 16:^.; iiei]ie\e\, Ann. N. H.
2 ser. xiii. 25G ; Braun, licjuv. (Bay Soc.
1853, 280, 292) ; Morren, Ann. Sc. Nat.
2 s^r.- v. 257 ; Focke, Physiol. Stud. 1847 ;
Osborne, Qu. Mic. Jn. iii. 54; Ileufrey,

» PI. 14. fig. 40.

t PI. 11. figs. 41 & 42 (Conjugation),
t PI. 14. fig. 43.
^ PI. 14. fig. 44.

16. J

17.

18.

19

20,

21

CLYPEASTER.

[ 185 ]

COAL.

Ann. N. H. 3 ser. i. 419 ; Pritchard, Infus.
74(3; Rabenliorst, i^/or. Ahj. hi. 123 ; Wills,
Jn. Mic. Soc. 1880, iii. 84-j.

CLYPEAS'TER, Lamk.— A genus of
Echinodevmata.

The hairs or spines springing from the
shell are beautiful microscopic objects.

CLY'TIA, Lam. — A genus of Hydroid
Polypes, fam. Campauulariidae.

1 Brit, species : C. Johnstoni-=- Campann-
laria roluhUis.

BiBL. Ilincks, Hyd. Zooph. p. 140.

CNEMLDA'KIA, Presl.— A genus of
Cyathese (Polypodiaceous Ferns). Now
consolidated with Hemitelia,

Fig. 129.

Fig. 130.

Fig. 131.

Fig. 132.

C. (Hemitelia) horrida.

rig. 129. Fragment of a pinnule, the sori covered by
indusia. Magnified 5 diameters.

Fig. 130. A sorus with indusium destroyed.

Fig. 1-31. The same, side view, showing the fragment
of the indusium at the base.

Fig. 132. Vertical section of a sorus.

Figs. 130-132 magnified 25 diameters.

COAL. — This substance, although classed
from its mode of occurrence in nature in the
mineral kingdom, is in all cases of vegetable
origin. The degree, however, in which
traces of organic structure may be detected
in it varies extremely. Coal may be either
tolerably irure, containing but shght admix-
ture of earthy matters, or it may contain
large quantities of earthy substance, and
pass gradually into a carbonaceous impreg-
nation of an earthy basis, as in the various
modifications of bituminous shales. In the

next place the degree of metamorphosis of
the vegetable matter may be equally varied,
so that we have it .still retaining its struc-
ture very evidently, as in liynites, «fcc., or
with the structure greatly destroyed, or
altogether lost, as in much ordinary coal and
anthracite, which however are apparently
of somewhat ditl'erent origin from the more
recent lignites. Some of the old coal-beds
appear to have been formed from depo.^its
analogous to our peat-bogs, and hence na-
turally consist in great part of vegetables
whose remains soon become imdistingiii,<h-
able; but that arborescent vegetation was
also prtsentand contributed to form the coal,
is proved by the detectic >n of woody .struc ture
somewhat like that of the Coniferse in certain
specimens of coal. Sometimes the woody
structure is even evident to the naked eye,
in a charcoal-like appearance of the frac-
tured surface or bed-planes of coal. In many
lignites the coal consists of trunks of trees
converted into coal without much alteration
of the appearance of texture of the wood ;
and in these the structure is very readily
made out by means of the microscope.
Some old coal is largely or entirely compo.'^ed
of sporangia of Lycopodiaceous or Lepido-
dendroid plants, cemented together by a
brown substance derived from the decom-
position of the tissues of the coal-formino-
plants. It would be out of place here to
enter upon the geological and chemical
questions connected with coal; the object
of applying the microscope to it is to ascer-
tain the existence or absence of organic
structure. For this purpose various methods
are employed. That most in use is the
preparation of exceedingly thin slices in the
manner usually adopted for fossil structures,
but the brittle and opaque character of
coal opposes great difficulties here. Traces
of structure may be made out in some
cases by grinding coal to fine powder and
examining the fragments ; but this plan is
very uusatisfactoiy. A third method is to
burn the coal to a white ash, and examine
this under the microscope : it often exhibits
perfect skeletons of vegetable cells, but the.^e
are very fragile, and require great care in
their management. By imbuing them very
cautiously with turpentine and Canada bal-
sam, and placing on the covering glass when
the latter has become rather firm, permanent
preparations may often be obtained. Schulze
recommends boiling in nitric acid before
incinerating the coal. Tlie method which
has been attended with most success in our

COB^A.

[ 180 ]

COCCOCHLORIS.

hfinds is as follows. The coal is maceraterl
for about a week in a solutiou of carbonate
of potash ; at the end of that time it is
possible to cut tolerably thin slices with a
razor. These slices are then placed in a
watch-o-lass with strong nitric acid, covered
and gently heated; they soon turn brownish,
then yellow, when the process must be ar-
rested by dropping the whole into a saucer
of cold "water, or else the coal woidd be
dissolved. The slices thus treated appear
of a darkish amber colour, very transparent,
and exhibit the structure, when existing,
most clearly. We have obtained longitu-
dinal and transverse sections of Coniferous
wood from various coals in this way ; al-
though this structure is most abundant in
lignites. The specimens are best preserved
in glycerine, in cells ; for spirit renders them
opaque, and even Canada balsam has the
same defect. Schulze states that he has
produced the cellulose reaction with iodine,
in coal treated with nitric acid and chlorate
of potash.

The proper identification of vegetable
structures in coal must of course depend
upon a sufliicient knowledge of the charac-
ters of vegetable tissues and organisms being
possessed by the observer.

BiBL. Withani, Fossil Vegefablcs, Edinb.
1833; Link, Abh. Bed. Akad. 1838;_.'J4;
Gfippert, Preisschrift iih. Steinkohlen, Leiden,
1848 ; Lindley and Hutton, Fossil Fl. ;
Schleiden and Schmidt, Geognost. Verhiiltn.
des SaaUhules, Leipzig, 1840 ; Ehrenbcrg
and Schulze, Berlin Bet: 1844; F. Schulze,
ibid. 1855 ; Ann. JV. H. xvi. p. 69 ; Bailey
{Anthracite), Ann. N. H. xviii. 67; Unger,
Gen. et Spec. Plant. Foss. 1850 ; Carruthers,
Mn. Mic. Jn. ii. 177, 225, iii. 144; Wil-
liamson, ibid. ii. 66 ; Lyell, Princip. of GeoL;
Huxley, Contemp. Rev. 1807 ; Dawson,
Acadian Geol. 1868; Mn. 31ic. Jn. 1870,
319 ; AYilliamson, Phil. Proc. ^- Trans.
1873 et seq. ; Zirkel, Mineralien, 1873, 257 ;
Reinsch. Steinkohle, 1881.

COB^E'A, Cuv.— A cliiubing Dicotyledo-
nous plant, of the Nat. Order I'olcmoniaceEe,
common in cultivatitni, remarkable for the
curious pvriforiu cells upon its seeds, con-
taining a spiral fibre (PI. 28. fig. 20). See
Spiral Structures.

COCCIDTUM.— A form of fructiEcation
in the Florit)E.^5.

COCCINEL'LA, Linn. (Lady-bird).— A
genus of Insects, of the order Coleoptera,
and family Coccinellidse.

C. septempunctata, the common lady-bird.

This insect exhibits the circulation through
the elytra. If one of these is separated
from the body without being detached, and
arranged in such a manner that it may be
viewed as a transparent object, slow and
uniform continuous currents, one ascending
and the other descending, will be seen be-
tween the lamiuaj of Avhich the elytrum
consists. On dividing the latter an amber
transparent hquid containing colomless glo-
bules-escapes.

BiBL. Nicolet, Aym. Sc. Kat. 3 ser. vii. ;
Westwood, Introd. Sfc. ; Curtis, Brit. Ent,
208 ; Stephens, Brit. Entom, ; Calver, Kd~
ferbuch, 690.

COCCOBACTE'RIA.— A term employed
by Billroth to designate the Schizomycetous
Bacteria and their allies. The author re-
gards the globular forms Coccos, and the
rod-like forms Bacterium and Bacillus, as
belonging to a single organism ; the former
arising from the division and spore-formation
of the latter, and the two forms being often
found in the same filament or zoogloea-form ;
the whole constituting his C'occobacteria
sepfica. Billroth gives new names to the
various forms, and regards them as colour-
less parallel states of many of the lower
Algse. The occurrence of these organisms
in various liquids, and tlnnr influence in the
production of decomposition and disease,
are fully treated in his elaborate and well-
illustrated treatise. (Billroth, C'occobacteria
septica, 1874.)

COCCOCARTE.E (Algaj). SeeCnYP-

TONEMIACEiE.

COCCOCARTIA, Pers.— A small genus
of mostly tropical Lichens, now united with
Pannaria.

C. (P.) plmnbea, Lightf., is British, and
has the thallus orbicular, livido-cinerascent,
aduate ; apothecia reddish-brown ; spores 8,
simple.

BiBL. Liglitfoot, Fl. Scot. ii. 820, pi. 26 :
Leighton, Lich.-Fl. G. B. 154.

COCC^OCIILO'RIS, Sprengel (Palmo-
f/lwa, Kiitz). — A genus of Palmellaceas
(Confervoid Algje), consisting of green mi-
croscopic cells, oval or globvdar, imbedded
in a gelatinous matrix, which is at first de-
finite in form (tliusdiii'eringfrom Palmella),
subsequently eliiised and shapeless. The
green cells are vesicles, filled with granular
colouring-matter (chlorophyll) Avhen in
active veiivtation. They nudtiply by divi-
sion ; and besides this, some of them grow
much larger than the rest, and their con-
tents are converted into a number of cells :

COCCOLITIIE.

L 187 J

COCCONEIS.

these large cells become free from the gene-
ral frond, and lav the foundation cif new
ones, originally of detinite form, which in-
crease in size by the division of the indivi-
duals within a persistent gelatinous invest-
ment. Brebissou, Ralfs, and Braun describe
a process of conjugation in C. Brebissonii
(PI. 7. tig. (5). Two cells come into contact,
and their membranes become fused ; the
intermingled contents then nndergo a meta-
morphosis, brownish oil-globules replacing
the chlorophyll ; and the ' spore-cell ' thus
produced passes through a period of rest
before resuming its vegetative development.
Thwaites states that the slender filamentous
bodies sometimes found in the frond are
part of the organization of the plant (see
Palmellaceje). Several British species
are described :

C. protuberans, Spreug. Frond green,
irregularly lobed, spreading on the ground,
cells eUiptical, about 1-30U0", enlarged vesi-
cles 1-500 to 1-1000". Hassall, Alffce, pi. 76.
fig. 7, pi. 82. figs. 6-10 ; Pabnella protube-
rans, Grev. Sc. Cn/pt. Fl. pi. 243. fig. 1.

C. muscicula, Meneghini. Hassall, /. c.
pi. 78. figs. 3 a, 3 b.

C./aj(iJuia,^ienegh. Freshwater. Hass.
I. c. pi. 78. figs. 2 a, 2 b.

C. depressa, Menegh. Hass. /. c. pi. 78.
figs. 4 a, 4 b.

C. Mooreana. Hass. /. c. pi. 78. 1 a, 1 b.
C. rivularis. Hass. /. c. pi. 78. 6 a b.
C. Grerillei, Hass. Frond minute, dense-
ly crowded, globose or somewhat lobed,
green. In healthy moist situations, fre-
quent. Hass. I. c. pi, 78. figs. 7 ab and 8 ;
Pabnella brotiyoides, Grev. Sc. Cnjpt. Fl.
pi. 243. fig. 2.

The plants are not yet satisfactorily im-
derstood ; the relations to Pahnella and
Gloiocapsa are confused.

BiBL. Meneghini, Monogr. Nostoch. ;
Kutzing, Phijc. gen. ; Braun, Rejuv. {Pay
Soc. 1853), as Pahnoglaa ; Thwaites, Ann.
N. H. ser. 2, vol. i'i. 312 (as Palmdla) ;
Niigeli, Einzell. Algen, 1849 ; Rabenhorst,
Fl.Alg.W. 67.

COC'COLITHE or COCCOLITE.— A
term applied to the granular varieties of
pyroxene (native silicate of magnesia, with
metallic silicates).

COC'COLITHS.— The name given by
Huxlev in 18j8, to minute oval or round,
calcareous bodies (PI. 23. fig. 56 6), 1-900"
and less in size, abounding in the Atlantic
ooze, either loose or attached to small lumps
of pi'otoplasm (' CoccosphereS;' Wallich).

Two foinns were recognized, Discolithi and
Ci/ntJioUthi. Similar niicroliths had been
noticed as forming a large proportion of
white chalk by Ehrenberg, Reade, and
Sorby. Wallich also found them in the
North Atlantic, in chalk, in tropical float-
ing Coccospheres, and in dredgiugs in the
English Channel. Haeckel subsequently
found them in the harbour of Lanzarote,
Carter in the English Channel, and Guem-
bel in limestones of all ages.

Ehrenberg termed these little bodies
' Morpholites of the chalk,' and regarded
them, like his ' crystalloids,' as due to the
rearrangement of calcareous particles. Sor-
by, Huxley, Wallich, and Haeckel differ in
opinion as to whether they exist indepen-
dently or not of Coccospheres. Carter
ascribes them to an Alga (Melobesia).

Coccoliths of either kind, treated with
dilute acid, leave a soft flexible cast or film,
which is coloured yellow by iodine, pale
red with carmine, red by Millon's test, and
is dissolved by alkalies.

BiBL. Ehrenberg, Monatsber. Ak. Berlin,
1836 ; Poqg. Ann. 1836, xxxix. 101 ; Ab-
handl. Ak. Berlin, 1838, 67 ; N. Jahrb. f.
Min. 1840, 080; Journ. prald. CJiemie, 1840,
xxi. 95 ; Edin. N. PJiil. Journ. 1841, xxx.
353 ; Mikrogeohgie, 1854 ; Reade, MantelFs
Wonders of Geology, 7th ed. ii. 953 ; Huxley,
Ueep-sea Soundings, ^c. 1858, 64; Qu.Mic.
Journ. 1868, 203 ; Wallich, Life at Great
Depths, 1860, 13 ; Ann. Nat. 'Hist. 1861,
vii. 396, ibid. viii. 52 ; Sorby, Proc. Lit.
Phil. Soc. Sheffield, 18G0 ; Ann. N. H. Sept.
1861 ; Haeckel, Jen. Zeitschr. v. 1870 ;
Guembel, Jahrb. Miinch. 1870, 753 ; Carter,
Ann. N. H. 1871, vii. 184.

COCCONETS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, depressed, adnate;
valves elliptical, one of them with a median
line and central nodule.

The valves are mostly covered with dots
(minute depressions), appearing like lines
under a low power.

The upper valve differs from the adnate
one in not being furnished with the central
nodule : under a low power it appears to
have a median fine as well as the adnate
valve ; but this, in some at least, arises from
the dots or markings at this part being more
closely in contact than elsewhere.

The frustules are often found densely in-
crusting filamentous Algte.

C. pedicidus {V\. 16. tig. 17). Frustules
very slightly arched (front view) ; valves

cocco^:ema.

[ 188 ]

COCOA.

elliptical, strife longitudinal, faiut ; length
1-1200 to 1-700" ; aquatic.

C. flacentula. Frustules tiat ; valves el-
liptical ; striae longitudinal, faint ; length
1-760" ; fresh water, common.

C. scutellum (PI. 16. fig. 16). Frustules
dorsally convex ; valves ovato-elliptical,
striae transverse or slightly curved ; length
1-700" ; marine. /3. Nodule dilated into a
stauros.

C. Thwaifesii (^Achnanthidimn Jtexettum,
Bre'hiss., Kiitz.). Ends of valves slightly
produced ; fresh water, length 1-900".

C. Grevillii. Oval, with transverse cana-
licidi ; marine.

C. diaplmna. Elliptical, diaphanous ;
marine.

Kabenhorst describes 37 European spe-
cies, with numerous varieties ; and enu-
merates 37 foreign species (with the re-
ferences).

BiBL. Ehrenb. Infm. ; Kiitzing, Bacill.,
and Sp. Aly. oO ; Smith, Brit. Dial. i. 21 5
Rabenhorst, Flor. AUj. i. 98 ; Greville,
Micr. Tr. 1804, 9, I860, 33, 1866, 126.

COCCONE'MA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules stipitate, navicular, some-
what arched (side view) ; valves with a
submedian line, with central and terminal
nodules ( = stipitate Cymbellce). Fresh
water.

Valves transversely striated, the striae
being resolvable into dots.

7 European species (Rab.).

C. lanceoJatum (PI. 16. figs. 19 & 20).
Front view of frustules lanceolate, truncate
at the ends ; valves semilanceolate, very
sUghtly inflated at the centre of the concave
margin ; length 1-150", Common. Stipes
dichotomous, jointed.

C. cymhiforme. Scarcely distinct from
the last (Sm.) ; stipules fihform, obsolete,
interwoven into a gelatinous mass ; length
1-330".

C. cishtla. Front view elliptic-oblong,
obtuse ; valves inflated on concave margin ;
stipes elongate, filiform, simple or subrace-
mose ; length l-4o0" ; common.

C. parvum (Sm.). Several other foreign
species.

BiBL. Ehr. Inf. ; Smith, Br. Dmf. i. 75 ;
Kiitz. Bacill., and Sp. Ah/. 59.

COCCOSPILE'RA, Perty.— An obscure
genus of Infusoria (Algae ?), consisting of
veiy minute spherical granules, with a black,
brown, or red nucleus, aggregated into ir-
regular revolving lumps, 1-400" in diuni. ;

they exhibit slow motion. Tn turf-pits
&c.
BiBL. Pertv, Kleinst. Lehens. 1852, 104.
COCCOSPHERES.— The name given
by WalHch to minute lumps of colourless
protoplasm, found in deep-sea ooze, and
floating in the tropics. He describes them
as spherical or multilobed, from 1-5000 to
1-830" in size, imitating in shape Orbulina,
Nudosaria, Texiilaria, Rotalia, and Globi-
c/erina, and coated with numerous oval
Coccoliths (PI. 23. fig. 56 o).

From the Atlantic ooze, also, Huxley
describes minute granular colourless sarcodic
bodies as Coccospheres, 1-4500 to 1-1700"
in diameter, some having Coccoliths on or
in them ; and he distinguishes (1) the com-
pact, hoUow, flattened sphaeroids with an
envelope, and (2) loose (1-4500 to 1-760").
The corpuscles are free, touching or over-
lapping, 1-11000 to 1-4500" in breadth,
sometimesmingied with Coccoliths(l-11000
to 1-1600").

BiBL. That of Coccoliths, and WalUch,
Ann. A^. H. 1877, xix. 342 (figs.).

COCCUDI'NA, Duj.— A genus of Infu-
soria, of the family Ploesconina.

Char. Body oval, depressed or almost
discoid, often shghtly sinuous at the luargin;
convex, furrowed or granular and glabrous
above : concave beneath, and furnislied with
vibratile cilia and cirri or corniculate ap-
pendages, ser^ ing as legs ; no mouth.

The species pf this genus known to
Ehrenberg are arranged among his Oxy-
trichina and Euplota.

C. costata (Pl_. 50. fig. 3). Body obliquely
narrowed and sinuous in front, convex and
furrowed above, or with from five to six
very pi'ojecting tubercular ribs ; appendages
grouped at the two ends ; the anterior more
slender and vibratile ; length 1-950" ; in
marsh-water.

Three other species. Dujardin remarks
that Ehrenberg's genus Aspidisca belongs
here.

BiBL. Dujardin, Infns. 445 5 Claparede
and Lachmaun, Inftis. 188.

COCKCHAFER. See Meloloxtua.
COCK-ROACH, or house black-beetle.
See Blatta.

COCOA. — This substance consists of the
seeds of Theobronia Cacao (Ternstra?mia-
cex), and is largely used in a manufactured
form under this name ; and, mixed with
sugar and other ingredients, it forms choco-
late. The various powders and pastes thus

very extensively

designated are often

COCOA-NUT.

[ 189 ]

CODOSIGA.

earths to disguise

faltiified. A difference of quality is in the
first place produced by the admixture or
exclu!<iou of the husk of the seeds ; still
more important degradation arises from
the use of flours of various kinds, ground
roots such as chicory added to give weight,
together with coloured
these.

The tissues forming the husk of the Cocoa-
seed include outer loose filamentous cells,
belonging rather to the seed-vessel ; a mem-
brane composed of a single layer of flat
parenchymatous cells with thin walls (PI. 2.
tig. 4 a) ; and another, thicker, consisting of
a number of layers of large parenchymatous
cells containing mucilage and crystals (fig.
4 b), with spiral vessels and woody fibre ;
the outer part of the dark-coloured albu-
men of the seed is composed of angidar, the
internal mass of rounded cells of delicate
structure filled with oil-globules and starch-
granides (PI. 2. fig. 4 e). In the interspace
between the lobes occurs a finely fibrous
tissue, in which are found crystals. The
presence of the filamentous, the large paren-
chymatous cells, and the spiral vessels indi-
cates when the bark has been gi'oimd up
with the finer part of the seed.

The various fioiu's and starches are to be
detected by the characters of their granules
(Stabch) : the pitted ducts betray the pre-
sence of chicory or other roots (see Chi-
cory).

Chocolate is a compound made up Avith
starches and sugar, and flavoured with
cinnamon, vanilla, and other ingredients.
The examination of its preparations must
perhaps be hmited to comparative richness
in cocoa, and to the detection of coarse sub-
stitutes for arrowroot and similar starches.
BiBL. Ilassall, Food and its Adult. 207.
COCOA-NUT.— The seed of the Cocoa-
nut Pahn, Cocas mieifera (Monocotyledon).
Sections of the remarkably hard shell of
this nut afford good specimens of veiy
greatly consolidated woody tissue ; while
the fleshy contents form an example of
oily albumen, the soft thick-walled cells
containing abundance of drops of oil in their
cavities. The husk of the nut is composed
of fibres analogous in their structure to
liber, and used for similar purposes. See

FiBBOrS STRUCTrRF..S.

CODI'OLUM, Braun.— A genus of Uni-
cellular Alga;, of which the only known
species, C. gregarium (PI. 5. fig. 6), is
marine. It consists of a clavate tubular
cell, attenuated from about midway into

a slender base, by which it is attached to
piles, &c. Length, when full-grown, about
1-2")", diameter of the clavate part about
1-300" ; green above, clear below. The
green contents are finally converted into
many 2-ciliated zoospores, which escape by
rupture of the cell, as in the sporanges of
Codium.

C. gregariwn was found at Heligoland, on
submersed timber, and may be looked for
on the British coast.

BiBL. Braun, AJq. Unicell. 1855, 19, pi. i.

CO'DIUM, Staciih.— A genus of Sipho-
nacese (Confervoid Algae) ; marine. The
species have dark green spongy fronds of
cylindrical, flat, globular or crust-like form,
some inches in size, composed of interlacing
continuous filaments devoid of septa, ter-
minating in radiating club-shaped filaments
at the surface (fig. 133). The sporanges

Fig. 133.

Codium tomentosujn.

Saccate cells arising from the filaments at the sorface.
Magnified 10 diameters.

(spores) are produced in lateral branches
from the clavate cells, forming long elliptical
sacs, the contents of which are converted
into a vast number of biciliated zoospores,
discharged when mature (PI. 6. fig. 15).

BiBL.' Harvev, Br. Mar. Alq. pi. 24 A ;
Phyc. Brit. pi. 93. 35 B ; and thuret, Ann.
&c. Nat. 3 ser. xiv. 2.32, pi. 23. figs. 1-5.

CODONEL'LA, Haeckel.— A genus of
Heterotrichous Infusoria (?) ; closely re-
sembling minute Medusee {Jen. Zeitschr.
1873 ; Kent, Inf. 615, figs.).

CODONCE'CA, Clark.— A genus of Fla-
gellate Infusoria.

Char. SoHtary, 1-flagellate, sessile, in an
erect stalked lorica.

2 species : marine and fresh water. (Kent,
Inf. 261.)

"CODOSI'GA, Clark.— A genus of Fla-
gellate Infusoria.

Cliar. Ovate, attached to a simple or

CCELASTRIUM.

[ 100 ]

OOLACIUM.

branched pedicle, with a collar, and a single
flagellum ; reproduction by longitudinal
division, and encysting, with division into
germs.

C. lotnft{s=Epkfylis h. Ehr. (PI. 53. fig.
15). Fresh water. 0 other species. (Kent,
Infus. .333.)

CCELASTRUM, Niig.— Agenus of Pedi-
astrese (?) (Confervoid Algae).

Cliar. Cell-grovip or frond globose, hol-
low internally, formed of a single relicidar
layer of green cells.

C. Kaer/elii (PI. 3. fig. 8). 3 other species:
found in boggy pools.

BiBL. Niigeli, Einzell. Aly. 97 ; Raben-
horst, Flor. Ah/, iii. 79.

C(ELENTERA'TA,Leuck.— AsiibMng-
dom of the Aximal Kingdom, composed
of the ZoophA'tes.

C(ELOCYS'TIS,Kiitz.— Probably a rest-
ing form of EuGLENA, Ilenf. ; = Coelospha;-
rhim, Rab.

CCELO'MONAS, Stein. -Agenus of Fla-
gellate Infusoria.

Char. Free, 1 flagellum, variable, mouth
leading to a larce chamber.

C.(jra7uUs = Monas (/. Ehr. (PL 53. fig.
16) : mar.sh-water. (Kent, Infus. 392.)

CCELOSPH^'RIUM, Niig.— A genus of
Palmellaceas (Confervoid Algse).

Char. Frond globose, minute, hollow
within, consi.^ting of minute aeruginous
cells immersed in a simple mucous enve-
lope.

3 species. In ditches and pools.

BiBL. Rabeuhorst, FLAhj. ii. 54; Archer,
Qu. Mir. Jn. 1879, xix. 440.

0(ENOCO'LEUS,Berk. and Thwaites.—
A genus of Oscillatoriacea;, distinguished
by the filaments growing ''within a tough,
shinny, more or less perujanent outer coat."
C. Smithii forms a red mat of interlacing
threads on boggy soil ; the separate.filaments
are gTeen. C. cirrhosum, Eng. Hot. p. 2920,
is a De-smonema.

BiBL. Bnqlhh But. 8uppl. pi. 2iM0.

CCENOCtO' JsIUM, Ehr.— A doubtful ge-
nus of tropical Lichens, usually placed
among the Lecideinei. The thallus has a
outicular stratum variously and curiouslj*
mnrked.

14 species, growing on leaves, trees, and
earth.

BiBT,. Leifrhton, Ceylon IJch. 172.

C(ENU'R'US, Rudolphi. — a supposed
genus of Entozoa, placed in the order Ste-
relraintha, and family Cystica : since proved
to be uurse-lbrms or lar^as of lanice.

Char. A simple vesicle filled with an
albuminous liquid, upon the outer surface
of w'hich a number of soft, short, retractile,
cylindrical and rugose rather than jointed
bodies (scolices) are situated. The head
of each resembles that of a T<ema, having
four di,slis and a crown of hooks.

C. cerebralis (PI. 21. fig. 10) is the larva
of Tcenia ccenurus, which infests the dog.

It occurs in the brain of sheep, producing
the " staggers ; " sometimes also in that of
the Hor.^e", the Ox, the Rabbit, &c. The
vesicle is as large as the e^g of a hen or a
pigeon. The scolices when extended are
about the 1-5 or 1-6" in length. When re-
tracted they appear to the naked eye as
opaque white specks.

Other kinds occur in the lemur and the
rabbit.

BiBL. Dujardin, Hehninthfs, 636; Kii-
chenmeister, Parasiten ; Cobbold, Entozoa,
1879.

COFFEE.— The "berries," as they are
vulgarly called, of coflee, are the seeds of
Cojf(Pa urnhica, a Dicotyledonous plant, of
the Nat. Order Cinchonacese.

The " berries " consist of a mass of hard
endosperm (horny Albumen), composed of
closely adherent thick-walled angidar cells
(PI. 2. fig. 5 b), with a thick skin composed
of a layer of thin-walled parench^niiatous
cells forming a membrane, and a layer of
hard, easily separable, ]iitted, thick-walled
pareuchjinatou? cells of larger size (PI. 2.
fig. 5 a) ; true spiral vessels occur in the
groove on the inner face of the seed. Ground
cofl'ee is subject to very extensive adultera-
tions, recognizable under the microscope ;
by which the vascular and parenchymatous
tissues of roots, the starch or the integu-
ments of various grains and seeds, &c. (men-
tioned more particidarl}' under Ohicoey)
may be discovered.

BiBL. Hassall, Food <St.

COIR.^ — The term coir-rope is applied to
cordage manufactured from the fibrous tis-
sue of the husk of the cocoa-nut. See
Fibrous Steuctubes.

COLA'CIUM, Ehr.— A genus of Flagel-
late Infusoria.

Char. IHagellum single, free like ^«/7/«?ffl
or attaclK^d by a simple or branched stalk,
gTeen, with red eye-spot.

C. vesicuhsvm '(PL 30. fig. 32). Oyato-
fusiform, variable, internal vesicles distinct,
length l-8()0". Fresh water, on Cyclops &c.

C. sfciiforium. Cylindrical, conical, or
funnel-shaped, variable, vesicles less dis-

COLEOCILETE.

[ lt>l ]

COLEOSrORIUM,

tinct, pedicel generally branched, bright
green ; length 1-800". Other species ;
mostly on Entomostraca (Ehr. Inf. 115;
Kent; Inf. 393).

COLEOCILE'TE, De Bri^biss.— A genus
of Cha;toplioracea3 (Confervoid Algaj), of
■which one species, C. sci/fata, is apparently
pretty common in freshwater pools, forming
minute green disks (fig. 134) adhering to
leaves, to the larger Confervffi, sticks, Sec,
also to the sides of glass vessels in wliich
aquatic plants are kept growing. The disks
are formed of a number of dichotomous
filameutsTadiating from a central cell and
cohering laterally, the whole being closely
applied on the surface of support, so tliat
the discoid fonn is occasionally modified by
this (we have seen it forming a kind of cup
and irreguhir fan-like lobes, on the ends of
the articulations of IIj/dn>dicfi/o7i). In cer-
tain cases the filaments are more or less free
from their lateral union. From the back of
many of the cells projects a long, tubular

Fig. 134.

Fig. 136.

Fig. 135.

Coleochaete scntata.

Fig. 1?4. A perfect plant. MBgnified 2o diameters.

Fig. 135. Cells with tubular processes from the back
of the frond. Mognifled r.0 diameters.

Fig \:Hi. CoDinii ncHnient of the development of a
young frond. Magnified KO diameters.

process (fig. 134), with a bulbous base. Re-
production by zoospores ; and by fertilized
resting-spores (oospores). The former are
produced singly in the cells, from the wliole
contents ; bear two cilia, and break out at
the back of the cell in C. smtata, from the
side in C. jmlvhiata. The resting-spores are
formed in cells near the margin, in penulti-
mate cells of the radiating filaments ; on the

back, therefore, in C. scutata, at the ends
of the branches in C. pnlvinafn. These en-
large very much, and become surrounded by
a kind of rind or cellular coat, through
growth of cellular branchlets frour the pre-
ceding and the surrounding cells, which
branchlets meet and enclose them. The
sporanges, with their trichogynes open at
the end, receive the spermatozoids, and
their contents are then converted into 5-8
resting-spores. The resting-spores do not
directly form new plants, but numerous
swarm-spores, and exhibiting alternations
of generations : the first swarm -spores pro-
duce only asexual plants, with repeated
broods of swarm-cells; finally comes asexual
generation, monoecious or dioecious accord-
ing to the species ; and then the spores or
oogonia. The antheridia are flask-shaped
cells, situated near the sporanges ; the sper-
matozoids are biciliated, one in each cell.

C. smtata, De Breb. (fig. 1.34) ; =PhyU
lactidium, Kiitz. Fronds discoid, sporanges
on the back. On aquatic plants, kc, com-
mon. A variety, /3 sohita, occurs with the
radiating filaments more or less free.

C. pulvinata, Eiaun. Fronds composed
of tufted-branched, radiating, free filaments;
sporanges globose, at the ends of the fila-
ments. Cheetop7iora tuberculata, 0. Miill,,
according to Kiitzing.

liabenhorst describes 7 species.

BiBL. De Brebisson, Ann. !Sc. Xal. 3 ser.
i. -I'd, pi. 2 ; Fvalfs, Ann. N. H. xvi. 309,
pi. 10; Hass. Alg. 1YI, pi. 77; Braun,
Rejuv. (Ray Soc. 1853) ; Kiitzing, »S);». Alg.
424 ; Miiller, Regensb. 'Flora,' xxv. B. ri.
513, pi. 3; Pringsheim, Jahrb. 1860, ii. 1 ;
Rabenh. Flor. Alg. iii. 388; Sachs, Rot.
289.

COLEOP'TEKA. — The 1st order of
Insects, containing the beetles. See Ix-

SECTS.

COLEOSPO'EIFM, Leveille.— A genus
of Urediuei (Hypodermous Fungi), sepa-
rated from TJredo, which proves to be a
secondary form of many distinct and inde-
pendent plants (see Ueedo). These fungi,
which may be well observed in C. sene-
cionis, Schlecht., and other common spe-
cies, appear as yellow, reddish, or brown-
ish pulverulent spots upon the leaves of
living plants. Their mycelium, creeping in
the intercellular tissues of the plants upon
which they are parasitic, consists of deli-
cate branched filaments, which collect toge-
ther at certiiiu points, become interwoven,
at the same time acquiring orange or yellow

COLEOSrORIUM.

[ 192 ]

COLLEMA.

cell-contents, so as to form a flat cusliion-
like body (clinode or stroma). From this
arise vertical or radiating, branched, club-
shaped, sac-like prolongations of some of
the filaments : the oldest are found in the
centre, the youngest at the circumference
of the group. The club-shaped bodies,
filled -with yellow or brown contents, be-
come firmlj'^ coherent laterally (at this stage
they constitute Uredo tremellosd). This
first spore is formed near the summit of the
clavate sac, leaving a little clear space at
the tip ; then a second spore below the first,
and so on to a third and a fourth, occa-
sionally to a fifth ; these increase in size so
as to conceal the existence of the sacs on
which they are seated ; only the tips of all
the laterally coherent sacs foi-m by their
imion a transparent layer, presenting, when
seen from above, somewhat the appearance
of the cornese of the compound eye of an
insect. This lamella is burst open, with
the epidermis of the infected plant ; and
the spores (now styhspoi-es), which grow
into oval and globular forms, become de-
tached from one another and lie loose,
forming the yellow, red, or brown pulveru-
lent spots above alluded to. The spores
have a granular cuticle, and their coat is
double. The above is the Uredo-foi-m ; be-
sides this there is another form of fruit, in
which the stalked rows of stylospores are
represented by oblong 4-5-locular sacs, each
of the chambers of which ultimately emits
a long slender tube terminating in a minute
reniform ' sporidium ' (Tulasne). British
species (we cannot find distinctive cha-
racters) :

C. synantherarmn, Fries. On Colt's-foot,
<S:c., common. U. comjyratisor, Schlecht.
(in part) ; U. tnssihiffirijs, Pers.

C. senecionis, Fr. On Groundsel, com-
mon. U. senccuinis, Schleclit.

C. campamdaccai'itm, Lev. On Campa-
nulcs. U, campamdcB, Pers.

C. rhinanthaccannn, Lev. On Euphrasia,
&c. U. rhinanthaccarum, De C.

C. pidsatillarum, Fr. U. ]mlsatillaru7n,
Strauss.

C. pinguis, Lev. On leaves, &c. of roses,
common. U. efftisa, Strauss; Grev. Sc.
Cnjpt. Fl. t. 10.

BiBL. Leveille, A^in. Sc. Nat. 3 ser. viii.
309; De Barv, lirandpdzc, Berlin, L'^53,
24, pi. 2 ; Fries, Summa Vct/et. 512 ; Berk,
in Jlook. Br. FL ii. pt. 2. 377-0, .'Vrc. ;
Tula-ne, Ann. Sc. Nat. 4 ser. ii. 135, 179;
Cooke, Micr. Fungi,

COLEPI'NA, Ehr.— A famUy of Infu-
soria.

Char. Carapace barrel-shaped, traversed
longitudinally or transversely, or both, by
furrows, in which are situated minute vibra-
tUe cilia; truncate, and either smooth or
dentate in front ; posteriorly pointed or ter-
minated by from two to five teeth ; fresh
and salt water.

Ehrenberg states that the oral and anal
orifices exist at the opposite ends of the
body. The gastric sacculi are readily filled
with colouring-matter. Motion, that of re-
volution upon the longitudinal axis.

A single genus : C'oleps.

CO'LEPS, Ehr. — A genus of Infusoria,
of the family Colepina.

Char. Those of the family.

These animals are very voracious, and
feed freely under the microscope upon the
portions of the body of crushed Entomo-
straca, which attract them as much as sugar
attracts flies.

C. hirtus (PI. 30. fig. 33 a, Ehr. ; fig. 33 i,
Duj.) Oval, white, rounded behind, cara-
pace tabulate, furrows transverse and longi-
tudinal; posterior teeth three ; length 1-570
to 1-430".

^ elo7if/aliis. Cylindrical, elongate, length
as in the last.

C. vir/dis. Ovate, furrows transverse and
longitudinal, green, posterior teeth three ;
length l-9(i0to 1-570".

C. ami^hacanfhus. Ovate, carapace di-
vided by transverse furrows only, anterior
teeth unequal ; posterior teeth three, large;
length 1-280".

C. incarvtis. Oblong, nearly cyhndrical,
slightlv curbed, white, posterior teeth five ;
length" 1-430".

C. tmcmatvs, Berlin ; fresh water,

C. ftisus, Norwav.

BiBL, Ehr. hif. 317; Duj. Inf. 565;
Clapar. & Lachm. Inf. .')G6 ; Kent, Inf. 506.

COLLA'KIUIM, Liuk.— A genus of Sepe-
doniei (Ilyphomycetous Eimgi). Filaments
crowded, septate, branched, with the spores
agglcjuieratid in little spots upon them.

C. nigrospennvm, on diied paste ; C.
frm-tigernm, on decaying apples. The
species should be referred to the Schizo-
mycetes.

COLLE'MA, Ach. — A genus of gelati-
nous Lichens. Thallus without cortical
laj^er, but consisting of a gelatinous mass
of cells, with granular gbnima in monili-
form series, and with I^ecanorine reddish
apothecia ; spores simple or septate. 40-50

COLLEMACEI.

[ 193 ]

COLLOSPH Ji:RA ,

species ; of whicli 27 are found on earth,
rocks, trees, See. iu Great Britain.

BiBL. Xylander, Si/n. 101, pis. 2,3,4;
Lei-iliton, Lic/i. Fl. 1879, 15.

COLLEMACEI.— A family of Lichens,
having a gelatinous tliallus ; compris-ing
the tribes LIC^E^■El and Collemei, which
see.

COLLEMEI. — A tribe of gelatinous
Lichens, fam. Collemacei, with a membra-
nous lobate thallus.

Gen. Pjfrenoiisis, Sijnalissa, Collema, Lep-
tof/iutn, Collemopsk, and Pi/renidhwi.

"COLLEMOP'SIS, Nyl.-A genus of Col-
lemaceous Lichens, with the thallus glau-
cous-green internally. 7 British species.

BiBL. Leighton, Lich. Fl. 35.

COLLEXt'HYMA.— A peculiar kind of
thickening of celkdar tissue iu the subepi-
dermal layers of many herbaceous stems,
such as limner, Beta, Chenopodiiim, &c. ;
which some have regarded as intercellular
substance, while others, more correctly, have
stated it to consist of metamorphosed se-
condary layers inside the cells. See Inter-
cellular SuBST.AJvCE.

COLLETONE'MA, Brebisson.— A genus
of Diatomace8e.

Char,

Frustules navicular, sigmoid or

straight, arranged in rows, and immersed
in a gelatinous mucus, forming a filiform
frond. Fresh water.

C. eximiimi. Valves sigmoid ; length
1-340".

C. vulgare. Valves elliptic-lanceolate,
slightly contracted at ends ; length 1-
410".

C. neqlectum. Valves elliptic-lanceolate ;
length i-250".

6'. suhcohcerens = Micromega suhcohce-
rens.

Three other species, C. viridulum, C. la-
custre, and C.Jle.vile.

Rabenhorst aiTanges these in a section of
the genus Sckizonema,

BiBL. Smith, Brit. Dial. ii. 69; KUt-
zing, Sp. Alg. 105 ; Rabenhorst. Fl. Alg.
i. 265.

COLLOID MATTER, exudation and
CORPUSCLES (animal).

The term colloid matter or exudation is
applied to a transparent, viscid, yellowish,
structureless or slightly granular matter,
resembling liquid gelatine, arising from the
metamorphosis of the protoplasm of the
cells. It occm-s as a normal and a patho-
logical product. In a state of greater con-
sistence, it sometimes forms flakes or irre-

gular masses, which occasionally possess a
laminated structure. In a third form it
constitutes spherical, rounded or oval,
sometimes flattened microscopic corpuscles
— simple masses of sarcode (Pi. 38. flg.22«).
These are either homogeneous, or exhibit
numerous laminte (concentric colloid cor-
puscles) (PI. 38. fig. 22 h) : sometimes a
kind of nuclear body is present (fig. 22 c);
at others they contain carbonate and phos-
phate of lime (fig. 22 cZ). Sometimes they
exhibit a radiate appearance (fig. 22 e). In
the liquid form, colloid exudation is found
■within cysts iu the thymus and thyroid
glands, the ovary, &c., and within the en-
larged areolae of areolar tissue around these
organs, &c. It is found in a free state upon
the surface of inflamed serous membranes.

The colloid corpuscles are met with in
the hypertrophied heart, in the prostate, the
thyroid, and the thymus glands, in the
choroid membrane, in the brain and spinal
cord, and iu the (waxy) spleen, &c.

The liquid colloid matter is not precipi-
tated by acetic acid ; it becomes of a
gelatinous consistence, retaining its trans-
parency or turbid and opaque, by heat.
The colloid corpuscles do not, however,
appear to be uniform in composition : some-
times they consist of a proteine-compound ;
at others, doubtfully, of cellulose or amy-
loid, as iu the brain (true Corpora ahy-
lacea). These bodies are further noticed
under the heads of the tissues and organs
in which they occm*. See also Tumours
{Colloid cancer).

BiEL. Rokitansky, Path. Anut. 1. 304;
Wedl, Path. Histol. ; Forster, Hand. spec.
Path. ; Virchow, Arch. Path. Anat. v. ;
Rindfleisch, Path. Gexvehelehre, 29 ; Green,
Pathol. Sf-c. 57.

COLLO'MIA, Nutt.— A genus of Pole-
moniaceas (Dicotyledons) remarkable for
the spiral structures produced in the epi-
dermis of the seeds (PI. 28. fig. 22) (see
Spiral Structures). The gummy sub-
stance in which fibre is imbedded is solu-
ble iu water and not in spirit ; therefore
the best way to observe the elastic opening
of the spiral fibres is to make fine sections
of the coat of the seed and place them in a
little spirit of wine, 'upon a slide, with a
covering glass, to adjust the focus, and
then to add water carefully at the side of
the covering glass so as to wash away or
dilute the spii-it.

COLLOSPILFIRA, Mlill.— A genus of
Radiolariu, fam. Thalassicollidae.

o

COLORADO BEETLE. [ 194 ]

COLPODA.

Chart Skeleton consistinp; of simple sphe-
rical roundish or polyhedral fenestrated
shells, smooth or spinous, each of ■which
surrounds one of the combined central
capsules.

C Iluxleyi {ThaJassicoIIa punctata., pt.).
Shell smooth: diam. ^J^". In various seas.

C. spiiiosa. Shell spinous, Lessina.

BiBL. Haeckel, JRadwka: 533 ; Iluxlev,
Ami. N. II. ]S51, viii. 434, pi. 16. fio-. 6. '

COLOEADO BEETLE. See Dory-

PHORA.

COLOSTRUM.— The first liquid se-
creted by the mammary glands. See
Milk.

COLOUR. SeelNTEODTTCTiONjp.xxxiv.

COLOURING MATTER, of Animals.
See PiGJJENT.

COLOURING MATTERS, of Pxants.
— The gi'een colour of vegetables depends
upon the presence of Chlorophyll, and
is spoken of under that head. The red and
yello'w colours assumed by leaves and her-
baceous shoots in autumn depend upon a
chemical metamorphosis of the chlorophyll,
or on its absorption and the discoloration of
the cellular tissue. The colours of red
cabbage, copper beech and similar plants,
depend upon the existence of a colouring-
liquid in the usually colourless epidermal
cells, obscuring the chlorophyll wliich lies
beneath. The red colour presented by many
of the lower Algas, such as some of the
Palmellacea5, appears also to depend upon a
metamorphosis of the chlorophyll, con-
nected with the vital processes ; it is met
with also in the contents of the resting-
spores of many of the iilamentous Confcr-
voids. The protoplasm assumes a reddish
colour in the functmn rer/etatiunis of the
buds of Monocotyledons in the autumn,
which probably depends upon a similar
cause. The bright coloiu's of flowers and
other parts of the inflorescence of plants, as
also of the lower surface of many leaves
(L'c(/(mi(r, Vidoricc, &c.) and herbaceous
shoots, arise from the presence of matters
of a difterent kind, almost always dissolved
in the watery cell-sap. The colour of petals
is ordinal ily found to depend upon a cer-
tain number of the cellssubjacentto the epi-
dermal layer being filled with a coloured
fluid ; and the depth of the colour is pro-
portionate to the number of superimposed
layers of such cells, which act like so many
layers of a pigment. Each cell is usually
filled with one colour when fully deve-
loped ; but adjacent cells arc often seen,

in variegated petals, to contain distinct
colours, the line of demarcation being accu-
rately fixed by the cell-walls, through which
the colours do not transude, unless the cells
are injured by pressure. In young tissues
the colour often has a granular appearance
in the cells; but this is a deception arising
from the mode in which the colour is deve-
loped. The colourless protoplasm originally
filling the cells becomes excavated, as it
were, by water-bubbles, and the watery
contents of the excavations become co-
loured ; they gradually enlarge as the pro-
toplasm applies itself more completely to
the walls of the cell, until they become
confluent and the coloured liquid fills the
whole cell-cavity. The isolation of the
coloured juice in each particular cell seems
to depend upon the primordial utricle or
pjirietal layer of protoplasm ; when this is
injured by pressure, or other external cause ,
endosmose is soon set up and the integrity
of the cell destroyed.

In some cases the liquid colouring-matters
of flowers have been found to contain solid
corpuscles : the red colour-cells of Salvia
splendens, and the blue ones of Stn'Iitzia
irr/iva, contain globules ; and according to
Mohl, this is still more commonly the case
Avith the yeUow colours : in the yellow
perigonial leaves of Sfrelitzia rer/ina the
yellow colour is said to depeud upon the
presence of crescentic and curled filaments
floating in the cell-sap.

The Avhite patches upon variegated and
spotted leaves, such as those of Auciiha,
Holly, variegated Mint, Becjonia anjyro-
stigma, &c., arise from the absence of chlo-
rophyll in the cells sulijacent to the epi-
dermis at those parts, which produces the
same effects as we see in leaves mined by
caterpillars.

BiBL. Von Mohl, J^crm. Schrift. 575,

COLPIB'IUM, Stein, = Paramcehim h>l-
poda, Ehr. & CI. & Lachmann (Kent, Iiifi/s.
537).

COLPOCEPLI'ALUM.— A subgenus of
Liothenm (Anoplxtra).

C. hmyicaudtnn, and four other species ;
found on pigeons.

BiBL. Megnin, Paramtcs, 91 (fig.).

COLPO'DA, Schrank, Ehr.— A genus of
Ilolotrichous Infusoria, of the family Col-
podea, Ehr., Colpodina, CI. & L.

Char. No ej^c-spot ; . body sinuous or
notched on one side, sometimes reniform,
surface reticulated or marked with nodular
obliquely interlacing strite ; mouth lateral,

COLrODELLA.

C 195 ]

CONCHOPHTHIRUS.

situated at tlie bottom of the notch, and
furni.-^hed ^vith a projecling lip.

C. cuci/llus (PI. 31. fig. 2o). Turgid,
slightly compressed, reuit'orm, often nar-
rowed'in front ; length 1-1720 to 1-280".
Common is vegetable infusions, especially
of hay. Ecdysis has been observed iu this
animalcule.

Stein describes the encysting process and
reproduction from germs as occurring iu
this infusorium.

C? rcn. Ovato-cyliudrical, reniform,
rounded at the ends ; fresh wat. ; length
1-280".

C. ? cuculUo (Lo.rodes cue, Duj.). Com-
pressed, iiat, elliptical, slightly sinuous in
front ; fresh Avat. ; length 1-000".

C. parvi/rons, CI. & L. No anterior re-
curvature, contractile vesicle not terminal.
Fresh Avater.

BiBL. Ehr. Inf. 347; Duj. Inf. 478;
Stein, Infusionsth ; Claparede & Lachmann,
270; Kent, 7>?/Ws. 512.

COLPODEL'LA, Cienk.— A genus of
Fliigellate Infusoria.

Char. Free or adherent, ovate or elon-
gate, one flagellum, with a suctorial cavity
at the base ; becomes encysted.

C. pm/nax (PI. 53. fig. 14). Fresh water ;
previuaon Chlmnydojnonas; length 1-2000".
(Kent,V»/: 378.)

COLPODI'NA, CI. & L.— A family of
Infusoria, characterized by the presence of
cilia all over the body, the patent and cili-
ated oesophagus, and the absence of rows
of buccal cilia directing the particles of
food to the mouth.

Genera :

Membranous lips absent.

No setae projecting from the
mouth

1.

Parameciitin.

Setae projecting from the mouth.
A bundle of short setae form-
ing a lower lip 2. Colpoda.

Oral setoe long, isolated.

No ventral setEe 3.

A bundle of ventral seta?... 4.

Lips membranous, oscillatory 5 .

CycUdium.

I'leuronema,

Glaucoma.

COLPONE'MA, Stein.— A genus of
Flagellate Infusoria.

C/iar. Free, ovate, pointed and curved,
with a ventral groove ; flagella two, one
apical and vibratile, the other ventral and
trailing.

C. lo.rodes. Fresh water (Kent, Inf.
297).

COLUREL'LA, Borv, Duj. = Colums,
Ehr.

_ COLU'RUS, Ehr.— A genus ofEotato-
ria, of the family Euchlanidota.

Char. Two frontal eye-spots ; tail-like
foot forked ; carapace cylindrical or com-
pressed.

Carapace open beneath ; cervical append-
age curved; jaws with two or three teeth
each.

C. defle.vtis (PI. 43. fig. 12, dorsal view;
13, ventral view; 14, teeth). Carapace
ovate, compressed, its posterior points
long and directed downwards; terminal
points of foot (toes, E.) shorter than the
foot itself; length of carapace 1-240".
Freshwater.

C. caudatus. Carapace ovate, compressed,
posterior points of carapace distinct, points
of foot longer than the foot itself ; fresh-
water and marine ; length 1-240".

C. ? imcinatus and bicuspidatus are doubt-
ful species.

BiBL. Ehr. Infus. 475.
COMBEA, D.'N.— A genus of podetii-
forni Lichens, tribe Eoccellei. 1 species,
C. moUusca ; rocks. Cape of Good Hope.

BiBL. Ach. Meth. 235, pi. 4. f. 5 ; Nyl.
Sijn. 257, pi. 8. f. 1.

COMPKESSOPt. Introduction, p.
xxiii. ; Ross's new compressor is described
in Qn. Micr. Jn. 1864, 44,

COMP'SOGON, Mont.— A genus of Le-
maneece (Confervoid Algaj).

1 European species : C. Corinnldii. Ca-
piUarv, much branched, violet. Freshwater,
CONCEPTACLE.— A form of fructifi-
cation in the Flobide^ and FrcoiBE^.
Also occurring iu the fructification of some
Fungi.

CONCHCE'CIA, Dana.— A genus of Os-
tracode Entomostraca, fam. Couchoeciadae.
Char. Those of the family.
C. obtusaia^ Sars. Shetland.
BiBL. Dana, Crustac. Explor. U.vpedit.
Sec. ; Sars, Oversigt af Noryea mar. Ostr.
118 ; Brady, Litm. Tr. xxvi. 469.

CONCHCE'CIAD^.— A family of En-
tomostraca, of the order Ostracoda.

Char. Inferior antennte 2-branched, one
branch rudimentary and immoveable ; feet
2 pairs, posterior rudimentary, eyes none.
1 genus, Conchcecia.

CONCHOPHTHI'RUS, Stein.— Agenus
of Ilolotrichous Infusoria.

Char. Free, oblong, dorsally convex,
striate.

C. anodontce= Lencophrys an. Ehr. In
the '' body-mucilage " of freshwater Mol-
lusca. 2 other species. (Kent, Inf. 490.)

o2

CONCEETIONS.

[ 196 ]

CONFERVA.

CONCRETIONS and CALCULI.—

These terms are rather indefinite. A hard
body of comparatively considerable size,
formed -within an animal organism, would
be called a calculus, whilst a body of con-
siderable comparative size in which hard-
ness was not a marked feature, or a Lard
body of small or microscopic dimensions,
would be called a concretion. Under the
latter term, the notion of a compound
structure is usually implied. Calculi gene-
rally consist of various organic and inor-
ganic substances enteiing into the compo-
sition of the secretions of the body, which
are precipitated from various causes. Those
found in the intestinal canal are mostly
composed of imdigested vegetable tissues
derived from the food. Most, if not all,
calculi and concretions are mixed with ani-
mal matter (proteine-compouuds) derived
from the mvicous cavities in which they are
contained, — or simultaneously precipitated,
with their characteristic compounds, from
the secretions in the midst of which they
are formed. Hence when the proper cal-
culous matter is dissolved by a reagent
which exerts little or no action upon the
animal matter, a mass is left which exhi-
bits the form of the original body ; and the
organic cast often so resembles a cell, that
some hasty observers have attributed to
calculi a cell-origin.

Calculi and concretions enlarge by the
deposition of new matter upon their outer
surface ; and as this deposition is not uni-
form and uninterrupted, either in regard to
the nature or proportion of the respective
constituents, they mostly exhibit a lami-
nated structure. This is visible to the
naked eye in the larger ones, and evidenced
in those which are microscopic by the ap-
pearance of concentric rings, and of a
nucleus or nuclei. These concentric rmgs
and nuclei are distinguishable equally in
concretions formed artificially as in those
occurring naturally.

The inorganic matter in concretions is
in the crystalline state, the crystals being
usually small, gi-anular or radiate, and in-
termingled with the organic substance;
which arrangement is conveniently ex-
pressed by Ehrenberg's temi " crystalloid.''
The crystalloids have a great resemblance
to cells, fur which they have often been
mistaken.

BiBL. Taylor, 7/wi^. Catalogue, CcilcnW;
Quekett, Med. Times, 1851, xxiv. 551 ;
Grifiith, Med. Times and Gaz, 1862, xxv.

272; Rainey, Medico-Chh: Bev. 1857,
and Qu. Mic. Jn. 1858; Meckel, Mikro-
qeoloqie.

CONDENSER, Achromatic, BULL'S-
EYE, &c., for opaque objects. Lxteo-

DTTCTION, pp. xix & XX.

CONFER'VA, Plin.— a genus of Con-
fervacete (Confervoid Algse), which, as
restricted here, contains chiefly marine
species ; but we have thought it advisable
to retain in it the species separated by
Kiitzing as Chatomorpha and by Thuret as
Microspora ; so that our Conferva corre-
sponds to Ilassall's proposed genus Aplo-
ncma. The plants consist of unbranched
filaments, composed of cylindrical or moni-
liform cells, the length and diameter of
which have a very variable relation in dif-
ferent species, and containing starch-gran-
ules. The species with moniliform cells
form Kiitzing's GlccoiUa. They are repro-
duced by zoospores formed from the cell-
contents. Braun says that C. homhycina
produces four in a cell. According to
Thuret, C. cerea produces large numbers,
which escape hy a lateral orifice ; while the
species he describes as Microspora Jloccosa
forms a number which escape by a circular
dehiscence breaking up the filaments. The
zoospores are 2-ciliated in general, but
sometimes bear four. The spores have not
been observed; and hence Kiitzing has sug-
gested that the Conferroi may be sterile
forms of (Edoe/oniinn ; but the true CEdoyo-
niu produce solitary zoospores with a
crown of cilia. Rabeuhorst describes 30
species. British species : —

Freslncater.

C. homhycina, Ag. Filaments 1-3G0 to
1-180" in diameter, foiu- or five times as
lorg, foiTuing a yellow-green cloudy stra-
tum. Common in stagnant water. Dillw.
Confervcs, pi. GO.

C./occosr/, Ag. (PI. 9. fig. 11 J). More
robust ; articulations once or twice as long
as broad. 3licrospora Jloccosa, Thuret,
Ann.des Sc.Kat. 3 st^r. xiv. pi. 17. figs. 0,7.

Marine.

Thirteen species are described by Harvey
{Mar. Algce), of which C. a-rea, I)illw., is
one of the commonest, remarkable for the
large size of the tufted filaments, as thick
as nog's bristles, growing- 3 to 12" long, of
a yellow-green colom*. C. Melayonimn,
Web. and Mohr, has erect tufted filaments
equally thick ; while C. Linum, Roth, has

COXFERVACE.E.

[ 107 ]

CONFERVOIDE^.

entangled filaments twice as thick, deep
glossy green, and many feet long.

The cell-walls of these large marine
species present a curious striated appear-
ance when treated with acids, which led
J. Agardh, apparently erroneously, to sup-
pose they are composed of spind filaments.
(See Spiral Stecctures.)

BiBL. Harvey, Phyc. Brit. ; Thuret, loc.
cit. ; Kiitziug, Sp. Alg. ; Ilassall, Freshiv.
AUj. 213 ; Braun, Rrjuv. {Ray Soc. 1853,
184) ; Rabenhorst, FL Alg. iii. 322.

COXFERVA'CE.E.— A family of Con-
fervoideiB. Marine or freshwater Algte ;
composed of articulated filaments, simple
or branched ; cells cylindi-ical, shortish, not
conjugating. The fom-th and fifth genera
given below are placed here doubtfully ;
Stigeoclonium, if a good genus, leads to
Draparnaldia among the Chsetophoraceae.
Reproduction by zoospores ; spores un-
known.

Synopsis of the British Genera.

Conferva. Filaments unbranched. Zoo-
spores' minute, numerous in the cells. Sea,
brackish, and fresb water.

Glmotila, Microspora, Chatomorpha, Cla-
clophora. Filaments tufted, much branched.
Sea and fresh, water. Zoospores minute,
many in a cell.

Rhizoclonium. Filaments decumbent,
with small lateral rootlilie branches. Zoo-
spores minute, numerous. Sea, brackish,
and fresh water.

Ulothrix. Filaments simple, often fasci-
culated, joints short. Zoospores 4-ciliated;
two, four, or more in a cell. Fresh water.

Stigeoclonium. Filaments branched, form-
ing tufts, the ramules running out into
slender points ; cell-walls often dissolving
to emit the zoospores. Zoospores 4-ciliated,
one in a cell.

CONFERYOI'DE^ or CHLOROSPO-
RE^.— An order of Algas. The ChLjro-
spores or Confervoids, the lowest order of
the Algae, display a preponderating number
of truly microscopical plants, and constitute
one of the favourite and most instructive
fields of microscopic research. As yet, how-
ever, the minute history of development is
wanting in a very large number, Avhile the
facts akeady disclosed are so varied that it
becomes a matter of difiiculty to draAv up a
sketch of their characteristics in a brief
space.

Among the Palmellaceae we find some of
the simplest forms of vegetable life, -where

the organization is reduced to the condition
of a single microscopic membranous vesicle
enclosing nitrogenous contents, ordinarily
tinged with chlorophyll, and containing
starch . Such we have in Protococeus, which
in its various forms appears as a green or red
stain on damp surfaces, or a green or red
scum in water. These plants multiply by
the subdivision of the cells iuto two or four
new ones, which separate and repeat the
process. In addition to the vegetative
growth by subdivision, going on in damp air
(the cells being held together more or less
firmly in a gelatinous crust), the contents
of the individual cells are set free by solution
of the membranes when placed in w*ater,
and emerge as ciliated zoospores, endowed
with active motion. Advancing a step, we
come to a number of genera not yet w^ell
defined, in which the membranes of the
parent cells soften into a kind of gelatine,
during the process of subdivision, and hold
the new cells together in groups of defijiite
or indefinite form ; among these are Palmella
Gloeocapsa, and others of like nature, in
which at present no zoospores have been
discovered. In C'occochloris a process of
conjugation occurs. These genera exhibit
a res^iVi^form, characterized by the increased
thickness of the membrane of the cell, and
a change of the gi'een contents into a
brownish, reddish, or even crimson colour.
With the Palmellacese we shall associate
a number of Unicellular Algse, whose cha-
racters and affinities are still obscure.

The Ulvacese are not widely separated
from the Palmellaceae ; but the conjunction
of the cells into a definite membrane, indi-
cates a higher organization. In other re-
spects, however, they hardly differ more from
some of the more perfect genera of Palmel-
laceae, than those do from Protococeus ; and
therefore, although more conspicuous and
extensively developed than the Nostochaceae
and Desmidiacese, it seems natural to place
the Ulvacese near the Palniellacefe, espe-
cially as the reproduction by cell-division
and by zoospores is analogous in all respects
to what is seen in Protococeus, of which they
woidd appear to be the permanently aquatic
representatives. Prasiola and Schizogonium,
however, differ fro'm the other Ulvacete in
the absence of zoospores, the homogeneous
not gi-auular contents of the cells being dis-
charged as motionless spore-like bodies,
fi'om which new fronds grow up.

The Nostochaceae exhibit but a slight
advance in organization over the Palmel-

CONFEEVOIDE^.

[ 198 ]

CONFERVOIDE^.

lacas. They are composed of linear series
of cells, mostly inflated so as to give tlie
filaments a beaded appearance ; the linear
series increase in length by transver.-^e divi-
sion, and in some stages subdivide longitu-
dinally; larger globular cells (sporanges)
occur at intervals in the lines, with others
devoid of endochrome (vesicular cells,
ThAvaites). Diu'ing the increase, the older
external membranes soften into a gelatinous
coat. In Kosfoc, where the filaments accu-
mulate in large numbers, they he elegantly
curled and entwined in masses of this jelly,
which exhibit a more or less definite, lobed,
external form ; appearing to the naked eye
as gelatinous crusts or globular masses,
as they lie upon damp ground or among
mosses. Each sporange produces one
resting-spore, which breaks out from it in
germination.

Nearly allied to Profococcus stands a
family which until recently liave often been
regarded as animals, namely the Volvoci-
nese ; which consist essentially of groups of
organisms identical with the ciliated zoo-
spores, held together in a definite form by a
common membranous envelope or cceno-
biuni, through which the cilia penetrate, so
that the entire full-grown plant moves free-
ly in the water, as in Volvox, Gojiium, Pan-
dorina., &c. These plants multiply by divi-
sion, the swarm-cells conjugating; also by
resting-spores, which are formed after a true
fecundation by spermatozoids.

The Desmidiaceae form another tribe of
very simple organization, where the indivi-
dual plant is composed of a single cell ; but
here the coat or enclosing membrane is pe-
culiarly characterized by the assumption of
remarkable forms uulike any other vegetable
structures ; preseutingangular and escalloped
outlines or elegant processes projecting from
the wall, but always so as to exhibit a bi-
lateral symmetry. These cells are isolated
or arrauged in linear series or beautiful
complicated star-like groups, enclosed at
first in a common gelatinous envelope, but
readily breaking up into isolated frustules.
They are further remarkable for exhibiting
the process of conjugation with great dis-
tinctness; resulting in the production of
peculiarly formed bodies, zygospores, with
rigid external membranes, which are
generally regarded, probably correctly, as
sporanges. They are also reproduced by
zoospores.

The Diatomacea) are nearly related in
many respects to the Desmidiaceso ; but, on

the other hand, diverge from the ordinary
characters of plants so much in other re-
spects, that some authors have placed them
in the animal kingdom. Like the Desmi-
diacese, they are microscopic simple cells,
isolated or coherent in gi'oups ; and either
free, or imbedded in a definitely or indefi-
nitely formed mucous nidus. They difier
however from the I)esmidiacea3,in possess-
ing, when free, a more active power of loco-
motion, and also by being often attached
by a kind of foot, and this either singly or
in large poljq^iform famihes. Their great
distinctive character is the presence of a
sihceous coat to the cell, which preserves
the form of the organism when the soft parts
are removed by fire or acids. The cell-
contents of the Diatomaceae are usually of
a dirty yellow colour, the colour of the
chlorphyll being concealed by a yellow
matter — diatomine (phycoxauthine). The
reproduction is by division, and by conju-
gation, analogous to that of the Desmi-
diacese.

The Oscillatoriacese are truly filamentous
plants, the component parts of which , though
readily separating under external intluences,
are often combined into complex fronds in
their normal state. The filaments of this
group are mostly very minute, and exhibit
transverse markings, which in some cases
are so delicate that they cannot be regarded
as actual divisions of cell-contents by septa;
yet the filaments break readily across in
these places, and the fragments go on grow-
ing. In the larger forms the articulations
of the cell-contents are more distinct ; but
even here the filaments look like rows of
individual masses of cell-contents contained
in a common tube, forming a kind of sheath.
In some genera the filaments are contained
in bundles in secondary sheaths. The most
remarkable point about this tribe is the
occurrence of the peculiar kind of motion
in the typical genus OsciJlatvria, whence
it derives its name : the iilaments emerge
readily from their sheaths and wave back-
wards and forwards, and tlie broken frag-
ments oscillate like tlie beam of a balance ;
from what cause, or by what means, is still
undecided.

I'he only known mode of reproduction is
by the breaking up of the filaments into
longer or shorter pieces, or into single joints.
Peculiar large cells occur at the base of the
filaments of some of the adnate genera ; but
their nature is unexplained.

The Siphonacea) i^re plants of larger

CONFERYOIDE^.

[ 199 ]

CONFERVOIDE^.

dimeiisiou3 and higher organization than
any of the preceding; and indeed they are
placed among the lower Fucoids by some
authors. They seem to lis to be more in
place here. They are composed of tubular
cells of much larger size than those of any
other Confervoids, the entire plant often
consisting of one undivided tube, while in
other cases the brauche.> arise from true
articulations. In Bofri/duon a very cm-ious
structure is exhibited : the plant consists
of a tough membranous globule, tilled with
green matter, rising from a branched, colour-
less, root-like portion spreading in the damp
ground, the whole con-<istiug only of one
very large undivided cell. In Vaucheria
and liryopsis the tubular cell grows into a
long filament, more or le-s branched, but
not divided. In Ili/drodicfi/on, which from
its general structure appears referable here,
the plant is a large net with meshes half
an inch broad, the net itself being com-
posed of large tubes rounded at both ends,
articulated at the intersections of the meshes.
In Codium, the filaments are closely com-
bined into a spongy mass. The fructifica-
tion of these genera is very varied, so
that the group appears scarcely natural ; but
the plants ai'e all more or less anomalous,
and have affinities with very difterent tribes,
while the comparatively enormous cells of
which they are composed are peculiar to
them among the filamentous Confervoids.
Vcmcheria is reproduced by very large oval
gonidia covered with innumerable vibratile
cilia, by means of which they swim actively
in water ; the gonidia are developed from
the contents of the ends of the filaments ;
and zoospores, produced under various cir-
cumstances, seem to occur in all the other
genera. In Vaucheria sexual reproduction
is also known ; sporangial and autheridial
branches being formed at the sides of the
main filaments. The Saprolegnxecc {Achhja,
Sec), were formerly included in this family,
on account of their general structure ; but
they are distinguished by the absence of
chlorophyll in their cell-contents, and their
parasitic habit, which gives them the cha-
racter of aquatic Fungi.

The ffidogoniacete are green, simple or
branched, filamentous plants, attached to fo-
reign bodies under water— their cells, filled
with green matter, presenting a pecidiar
mode of division; and the entire contents of
the cells are converted into zoospores which
have a crown of numerous cilia. In the
sexual reproduction, the spores are formed

from the entire contents of certain cells,
which are impregnated by sperniatozoids
produced on other parts of the plant, or by
antheridial plants developed from some of
the gonidia.

The Z3'gnemacea9 are somewhat similar
filamentous plants, remarkable for the pro
cess of CONJUGATION Or inosculation of
neighbouring cells of distinct filaments in
order to the production of the resting-
spores. They are also distinguished by the
endochrome being arranged in spiral bands
or other patterns on the cell-walls. It is
doubtful whether zoospores occur here
normally.

The Confervaceai are simple or brauclied
filamentous form*, of which the essential
characters are imperfectly known. They
produce numerous zoospores with two or
four cilia, in each cell.

The Chfetophoracese differ from the Con-
fervacefe principally in their habit and mode
of branching. They occur in fresh water
and in the sea ; and are chai'acterized by the
presence of a jelly enveloping the filaments,
which form branched, round, or shapeless
masses, or flat discoid or irregular plates,
and by the cells constituting the joints of
the filaments bearing slender bristle-like
branches. They are reproduced by zoo-
spores, either numerous or solitary' in the
cells, bearing four ciHa; also by spores
formed after fecundation.

The Batrachospermese exhibit a greater
complexity of structure, consisting of jointed
moniliform filaments, composed of rows of
cells, branched and bearing whorls of ramuli ;
the filaments of the whorls dense, dichoto-
mous, and beaded, some of them growing
down o^•er the central filament, and forming
a sheath round it. The fructification con-
sists of spore-like bodies, or cystocarps with
trichogynes, borne on the filaments of the
whorls, and of bodies resembling the an-
theridia of the Floridec-e. The plants are
brownish green or jjurplish, and occur in
fresh Avater.

The Lemaneeae are freshwater Alg£e, oc-
curring in rapid rivers, attached to stones,
by some supposed to bear a close relation to
the lower Fucoids. The fronds are branched
and of leathery textiu-e, consisting of tubes
composed of cellular tissue, — the superficial
layers small, polygonal, and firmly con-
joined— the deeper layers, bounding the
cavity of the tubes, lax and spherical. The
fructification consists of beaded filaments
arising from the internal cells, and grow-

CONFERVOIDE^.

[ 200 ]

CONFERVOIDEJE.

ing out freely in tlie cavity of tlie tuhe,
finally breaking up into the component
bead-like cells (sjwres), which reproduce
the plant. The genus Lemanea deserves

further investigation.

Synopsis of the Families.

Lemanee^. Frond filamentous, inar-
ticulate, cartilaginous-leathery, hollow,
furnished at irregular distances with whorls
of warts, or necklace-shaped. Fructijicafion :
tufted, simple or branched, necklace-shaped
filaments, attached to the inner surface of
the tubular frond, and finally breaking up
into elliptical spores. Freshwater.

Bateachosperme.^. Plants filamen-
tous, articulated, invested with gelatine.
Frond composed of aggregated, articulate,
longitudinal cells ; whorled at intervals with
short, horizontal, cylindrical or beaded,
jointed ramuli. Fructification: oyate spores,
and tufts of antlieridial cells attached to
the lateral ramuli, Avhich consist of minute,
radiating, dichotomous, beaded filaments.
Freshwater plants.

Ch^tophoeace^. Plants growing in
the sea or fresh Avater, coated by gelatinous
substance : either fihform, or (a number of
filaments being connected together) consti-
tuting gelatinous, definitely formed or shape-
less fronds or masses. Filaments jointed,
bearing bristle-like processes. Fnictificu-
tion : zoospores produced from the cell-con-
tents of the filaments ; resting-spores formed
from the contents of particular cells after
impregnation by ciliated spermatozoids pro-
duced in distinct antheridial cells {(Joleo-
chcste^,

Confervace.^. Plants growing in fresh
•water, or in the sea, filamentous, jointed,
without evident gelatine (forming merely a
delicate coat around tlie separate filaments).
Filanients very variable in appearance, sim-
ple or branched ; the cells constituting the
articulation of the filaments more or less
filled with green or very rarely brown or
purple grainilar matter, sometimes arranged
in peculiar patterns on the walls, and con-
vertible into spores or zoospores. Not con-
jugating.

Zygnemaceje. Freshwater filamentous
plants, without evident gelatine, composed
of series of cylindrical cells, straight or cur-
ved. Cell-cimtents often arranged in elegant
patterns on the walls. lieproduction result-
ing from conjugation, followed by tlie de-
velopment of a true sjwre, in some genera

dividing into four sporules before germina-
tion.

(Edogoniace^. Simple or branched,
freshwater, filamentous plants, attached
without gelatine. Cell-contents uniform,
dense. CeU-division accompanied by cir-
cumscissile dehiscence of the parent cell,
producing rings upon the filaments. Re-
2)roduction by zoospores formed of the whole
contents of a cell, with a crown of numerous
cilia ; and resting-spores formed in sporan-
gial cells after fecundation by ciliated sper-
matozoids formed in antheridial cells.

SiPHONACEs;. Plants found in the sea,
fresh water, or on damp ground ; of a mem-
branous or horny hyaline substance, filled
with green granular matter. Fronds con-
sisting of continuous tubular filaments,
either free or collected into spongy masses
of various shapes, either crustaceous, globu-
lar, cylindrical or fiat. Friicfijication by
zoospores either single or very numerous ;
and by resting-spores formed in sporangia!
cells after the contents have been impregna-
ted by the contents of antheiidial cells of
different form.

OsciLLATOEiACE^. Plants growing
either in the sea, in fresh water, or on damp
ground, of a gelatinous substance and fila-
mentous structure. Filaments very slender,
tubular, continuous, filled with coloured
granular, transversely striate substance ;
seldom branched, though often cohering
together so as tp appear branched, usually
massed together in broad floating or sessile
strata, of very gelatinous nature ; occasion-
ally erect and tufted, and still more rarely
collected into radiating series bound together
by firm gelatine, and then forming globose,
lobed, or flat crustaceous fronds. Fructiji-
cation : the internal mass or the cell-con-
tents, separating into roundish or lenticular
gonidia.

NosTOCHACEJE. Gelatiuous plants

growing in fresh water or in damp situa-
tions among mosses, &c. ; of soft or almost
leathery substance, consisting of variously
curled or twisted necklace-shaped filaments,
colourless or green, composed of simple (or
in some stages double) rows of cells, con-
tained in a gelatinous matrix of definite
form, or heaped together without order in
a gelatinotis mass. Some of the cells en-
larged, and then forming cither vesicular
empty crlls or densely filled, sporangial cells.
lieproduction by the breaking up of the
filaments,and by resting-spores formed singly
in the sporauges.

CONFERVOIDE.E.

[ 201 ]

CONTFER.E.

Ulvace.e. Marine or freshwater Algfe,
consisting of membranous flat and expanded
tubular or saccate fronds composed of poly-
gonal cells firmly conjoined by their sides.
Heproduced by zoospores formed from the
cell-contents and breaking out from the
surface ; or by motionless s/jo/ts formed from
the whole contents of a cell.

Pai.iiell.vce.^. Plants foiining gela-
tinous or pidverulent crusts on damp sur-
faces of stone, wood, kc, or more or less
regular masses of gelatinous substance, or
delicate pseudo-membranous expansions or
fronds, of flat, globular, or tubular form, in
fi'esh water or on damp ground ; composed
of one or many, sometimes innumerable,
cells with green, red, or yellowish contents,
spherical or elliptical form, — the simplest
being isolated cells (found in groups of two,
four, eight, &c. in course of multiplication);
others permanently formed of some multiple
of four; the highest of compact, numerous,
more or less closely conj oined cells. Repro-
duction by cell-division ; by the conversion
of the cell -contents into zoospores ; and by
restinr/spores, formed sometimes after con-
jugation, in other cases probably after
fecundation by spermatozoids.

We shall include under the head of Pal-
mellacepe, all those obscure Unicellular
Algfe whose place is not at present satis-
factorily known.

Desmidiace^. ^ Microscopic, gela-
tinous plants, of a green colour, growing in
fresh water ; composed of cells devoid of a
siliceous coat, of peculiar forms, such as
oval, crescentic, shortly cylindrical, or cylin-
di-ic-oblong, &c., with variously-formed rays
or lobes, giving a more or less stellate form,
presenting a bilateral symmetry, the junc-
tion of the halves being marked by a division
of the green contents : the individual cells
either free, or arranged in linear series, col-
lected into faggot-like bundles, or in elegant
star-like groups, which are imbedded in a
common gelatinous coat. Reproduced by
division, and by rcsfinff-spores produced in
sporanc/ia formed after the conjugation of
two cells and union of their contents ; and
by zoospores formed in the vegetative cells
(Pedias(>-U7n), or in the germinating resting-
spores.

DiATOMACE^. Microscopic cellular
bodies, growing in fresh, brackish, and sea-
water ; free or attached ; single or imbedded
in gelatinous tubes ; the individual cells
{frmfides) with yellowish or brownish,
rarely greenish, contents, and provided with

a siliceous coat composed of two usually
symmetrical valves variously marked ; with
a connecting band or hoop at the suture,
^lultiplied by longitudinal division ; and by
the formation of ncio laryer individuals out
of the contents of conjwjaled cells ; perhaps
also by spores and zoospores.

VoLvociNE.^. Microscopic, cellular,
freshwater plants, composed of groups of
bodies resembling zoospores, connected into
a definite form by their enveloping mem-
branes. The plants (families) are formed
either of assemblages of coated zoospores
united in a definite form by the cohesion of
their membranes, or of assemblages of naked
zoospores enclosed in a large common in-
vesting membrane. The individual zoo-
spore-like bodies with two cilia throughout
life, perforating the membranous coats, and
by their conjoined action causing a free
movement of the entire group. lie produc-
tion by division (Goninni) ; or by single
cells becoming converted into zoospores
which conjugate and form new families
{Pandorina, Volmx) ; and by resting-spores
formed from some of the cells after im-
pregnation by spermatozoids formed from
the contents of other cells of the same
family.

BiBL. See the Families.

CONID'IA.— The name applied by I'ries
to the stalked spores, stylogonidia, or repro-
ductive cells, produced directly from the
mycelium of many Fungi (PI. 26. fig. 8) :
characteristic of the Coniomycetes. Late
discoveries have rendered the term of some-
what equivocal value ; and it is not yet
sufficiently distinguished from Stylo-
spores and Spermatia. Physiologically,
they are regarded as equivalent to tlie
gonidia of Lichens.

CONIF'ER^.— A class of Gymnosper-
mous plants, so called from the peculiar
form of the female inflorescence, in which
the flowers are collected into imbricated
cones ; this is the case at least in the Abie-
tineaa and Cupressineae : in the Taxinese,
which are separated by some authors, the
female flowers are solitary. These plants
are remarkable in many respects. The pro-
cesses occurring in the fertilization of the
ovules are quite different from those in the
Angiospermous flowering plants, and form
a link with the conditions in the higher
Flowerless plants. (See Gymn-ospermia.)
The pollen (PI. 40. fig. 16) is of a remark-
able form in the Abietineae. The most
striking point, however, in relation to the

CONIFERS.

[ 202 ]

CONIOCYBE.

microscopic structure, is the condition of
the stems of these plants. The wood is
entirely composed of prosenchymatous cells,
of large size, without intermixture of ducts
or vessels; and those walls of the cells
parallel with the medullary rays (very
rarely those at right angles) are marked
with one or more rows of the peculiar bor-
dered pits which have been wrongly called
glands (PI. 1. lig. 4). The structure of
these is explained under the head of Pitted
Structures. It must be understood, how-
ever, that the pecidiarity of Coniferous
wood does not depend on the presence of
these, Avhich are common, but on the simul-
taneous absence of ducts. The wood of the
Yew presents in addition a spiral fibre, be-
tween the coils of which the pits lie. (See
Taxus.j These peculiar conditions of the
wood render it possible to identify it in
microscopic sections in a recent, and, if
tolerably well preserved, even in a fossil
state ; "the Coniferous structure may be
readily detected in silicihed wood, in which
almost all trace of organic matter is lost,
the silica forming complete casts of the
microscopic structures. Tliis is beautifully
seen in some silicified wood brought from
Australia by Dr. Hooker, parts of which
are so friable, that microscopic sections
may be obtained by splitting it with a
knife (PI. 25. tig. ;J3J. With solid silicified
wood, sections made by the lapidary are
required. We have also readily detected
the structure in Coal by the process we
have given under that head.

The only case of a structure approaching
near enough to that of Coniferous wood to
leail to misconception, appears to be that of
the wood of certain Magnoliacere, such as
JJrimys, Sphcerostema, and Tasmantiia,\yhe\'e
there is likewise absence of ducts and ves-
sels, while the prosenchymatous cells have
bordered pits; but the wood difiers consi-
derably in the character of the medullary
raj'S, and in the number and arrangement
of the pits on the Avails of the cells. (See

WiNTEREiE.)

The wood of many of tlie Conifers is
traversed by turpentine- canals, which are
large intercellular passages bounded by
thin-walled cells ; in others these occur
only in the bark, while in Ta.ius and Tvr-
reya both are devoid of them : wliere none
occur in the wood, there are generally iso-
lated rows of cells filled with secretions ;
but not even these occur in the wood of
Abies pcctinata.

The following analysis of the structure of
the wood of some of the most important, is
slightly modified from Ilartig : —

A. Cells of the pith mth thin walls,
a. Liber-cells in erofs-seclion broad \
and mostly short, isolated in scat- (. a „,pt,,„b. _
tered(jroups,orinbands ofseve- j'-a-amnNH.*..

ral rows, or wanting /

*Wood with turpentine -canals.

t Medullary rays with varying pits Pinus.
ttMeduIlary rays with uniform
pits.

jCords of secretion-cells at the
outer limitof the annual rings.
§Outer wood-cells of the an-} p^j„,,
nual ringi smooth within... ) '-'™"'*'
^^Outer wood-cells of the an-]
nual rings with an obscure >Larix.

spiral fibre J

JJWood without isolated rows } -p-

of secretion-cells ^Jricea.

**Wood without turpentine-canals,
t Medullary rays with distant pits.

I Wood-cells with distant jjits, I I aj ■

or -J rows in pairs ^^ces.

II Wood-cells with crowded pits,
1-5 rows, in spiral arrange-
ment.

4Wood without cords of se- ) >
cretion-cells \Araucana.

5$ Wood with cords of secre- I n „■ i

tion-cells \Cunninghamia.

ttMeduIlary rays with crowded l j-.

pits

ara.

b. Liber-cf.Us with square or oblong \

cross-section, ui concentric rows, ( Taxine.E and
alternating icilh parenchymatous rPoDOCARPE/E.
cells J

*Pith with thick-coated liber-cells . Salisburia.

**Pith ^Yithout thick-coated liber-
cells,
t Wood-cells with openly-coiled ) m

spiral fibre j-iaUTttS.

tt Wood-cells smooth within.

TLiber-layers with thick-coated ) ■„ ,

* Pi.lls . ^Podocarpus.

TTLiber-layers without thick- \ -r, ,.
coated cells \ Dacrydmm.

B. Cells of the pith tcith thick walls, ) «

liber-cells square ; [CUPEESSINE.E.

*Libcr-cells without pit-canals.
tPith with a roundish cross-sec-)

tion, bark without turpentine- r Taxodium.

caniils )

ttPith with quadrangular cross-)

section, bark with turpentine- >• r^K/n.

canals J

**Liber-celIs with pit-canals.
tWood-cells smooth inside.

JPilh ;!-angled Juniperus.

JPith 2- or l-angled Ciipressus.

t\Voi)d-cell8 with a spiral fibre, ) „ „., .

liker«x«^ : '\Calhtris.

BiBL. Goppert, Be Conifer. Stnic. 1841;
Anat. McKjnoliac. Linnsea, xvi. 135, Aim.
Sc. Nat. 2 ser. xviii. ; Ilartiir, Botan. Zeit.
vi. 12M, 1848; Schacht, Pfiunzenzelle, 435;
Ilenfrev-Masters, Bot. 358, U25; Sachs,
Bot. 40(').
_ CONIO'CYBE, Ach.— A genus of Cali-
ciei (Licheuaceous Lichens), distin-
guished by the yellow powdery thidlus,

CONIOMYCETES.

[ 20.3 ]

CONIOMYCETES.

globose yellow powdery stipitate liead-like
apotheeia, and colourless spores.

o European, 3 British species.

BiBL. LLntrhton, Lich. FL G. B. 45.

CONIOM YCE'TES.— A section of Fungi
composed of microscopic forms, for the most
part parasitical upon plants, growingbeneath
the epidermis, or overgrowing decaying ve-
getables, and then more or less imbedded in
the matrix. The fructification consists of
groups of sessile or stalked spores (sporiclia,
Fries, and sfi/lospores, Tulasne) arising from
the tilamentous myceliimi. In the simplest
forms the mycelium consists of short tila-
ments, which are more or less completely
converted into spores ; or it forms an irre-
gular tlocculeut patch in decaying matter or
under the epidermis of plants, in which the
spores are found intermingled, breaking out
on the surface of the epidermis in the para-
sites ; but in the more complete forms the
mycelium becomes organized into firm struc-
tures of definite form (concept acles) which
are hollow, the walls being lined with short
filaments terminating in spores. These
conceptacles are either produced on the sur-
face of the epidermis of the plant infested,
or they are formed internally, and are ex-
posed by breaking their way through to the
surface of the epidermal structures in which
they are imbedded.

'We must not omit, in giving a description
of this order as it stands in systematic works,
to notice that recent observations go to
prove that it rests upon a very insecure
basis, and that certain supposed genera be-
longing to it appear to be merely forms of
genera which exhibit at other stages of
growth, or even at the same time, asciferous
structures which have formed the bases of
Ascomycetous genera. The following is a
summary of the views of Tulasne on these
points : — The Hypoxylous Fungi possess
at least fom* distinct kinds of organs of re-
production, among which the conidia liold
the tirst rank ; these are bodies of various
forms arising directly from the mycelium,
or from the droma which is formed upon
this. Conidiiferous forms of Sphcieriacei,
which have been regarded as autonomous
Fungi, have given origin to the following
genera of this order: — Melanconium, Stilho-
spora, Stef/anospon'um, Coryneum, Exospu-
rium, Cylindrosporium, Macrosporium, Ver-
mictdaria, Mi/sfro-ywrium, C'laduspdriutn,
Hehninthospormm, Periconium, Polythrin-
dum, Tuhercularia,Stilbum,Atractium, Gra-
pliiiim. The stylospores are the naked and

primitive stipitate spores formed in the con-
ceptacles, called by Tulasne pycnidia; he
regards as pycnidial forms of Sphseriacei
most of the species of the genera Diplodia,
Sporocadus, Sp/ufropsis, Jlendersoiiia, M;,xo-
cychis, rhyllosticta, Phoma, and their allies.
These forms almost always occur united
with the perfect or Ascomycetous forms to
whicli they are to be referred. A third
kind of acrogenous bodies occur often in the
same conceptacles as the stylospores, but
are much smaller, ordinarily of linear form,
and are usually confounded ultimately into
a gelatinous mass ; these are the spermatia,
which are supposed to exercise a fertilizing
influence. The genera Cytispora, Nema-
spora, Libertella, Septoria, Chedaria, Lepto-
thyrium, &c., are chiefly based on the sper-
moyonous apparatus of Sphoeriacei. The
fourth form of spore is found enclosed in
asci ; the presence of these ascospores forms
the basis of the class Ascnmycetes. Further
details are given under the heads of the
families, and genera there referred to.

The Uredinei exhibit similar polymorph-
ism ; since the genera there included, such
as ALcidium, Puccinia, based upon the most
perfect form of fruit, mostly exhibit also
a stylosporous form (on which is founded
the false genus Uredo), together with sper-
mogonia containing spermatia.

Synopsis of the Families.

PHRAGiiOTBiCHACE.T:. Conceptacles

horny, breaking- through the epidermis of
leaves, &c., at first closed, afterwards burst-
ing longitudinally ; spores septate, and in
chain-hke series, intermixed with para-
physes on the internal walls of the con-
ceptacles.

Top.uLACEi. Mycelium filamentous,
growing on the surface of decayed vegeta-
bles, bearing erect filaments, terminating in
rows of simple or compound spores.

Uredinei. Mycelium a filamentous
mass growing in the interior of living vege-
table structures, finally brealcing out on the
surface in patches, margined or naked, and
bearing simple or compound spores, single
or in beaded series. ,

UsTiLAGiNEi. Mj-celium filamentous,
growing in the interior of organs of plants,
producing simple or septate spores, finally
breaking up, without bursting through to
the surface, so as to leave a cavity full of
dust-like spores.

BiBL. Berkeley and Broome, Iloolcers

CONIOPHYTUM.

[ 204 ]

COXJUGATION.

London Journ. of Bot. iii. 320; Tulasne,
Compt. Remhis, 'March 1851 {Ann. N. H.
1851, viii. 114) ; Ann. So. Nat. 3 S(5r. xv.
370, XX. 129, 4 ser. ii. 77, v. p. 108 ; Botan.
Zeit. xi. 49; Compt. Rend. 1854 {Ann. N.
H. 2 ser. 1854, 715) ; Fries, St/sf. Mijcol ;
De Bary, Brand-Pihe, Berlin, 1853.

CONIO'PPIYTUM, Hassall {Dolicho-
spermiim, Ralfs). — A genus of Nostocha-
cese (Coufervoid xAlgte), consisting of one
species ; colouring large sheets of water of
a deep coppery green, by its minute fronds,
each composed of a number of filaments
variously curled and interwoven, densely in
the centre, and more loosely towards the
circumference ; these fronds being free, look
like a pulverulent or granular accumulation
in the water, when viewed by the naked
eye. The genus differs from its allies in
the relative positions of the spermatic and
vesicular cells, the former being either
next to, or at a distance from the latter.
This fact seems to throw some doubt on
the value of this character as a distinctive
mark.

a Thompson!; Ralfs (PI. 3. fig. 9), = Z)o-
Uchospermnm Thomp., Ralfs, Ann. N. H.
1850, v. 33(3, pi. 9. fig. 3. Anahainn Flos-
aqitcs, Harvey, Brif. Algce, ed. 1 ; Hassall,
Algce, pi. 75. f. 2 ; also Bot. Gaz. 1850
{Colour of the Serpentine?).

COXIOTHE'CIUM, Corda.— Anobscure
genus of Torulacei (Couiomycetous Fungi) ;
the so-called species being probably forms
of some other Fungi.

C. amentacearum is extremely common
on dead wiUow-twigs.

BiBL. Berk, and Broome, Ann. N. H.
1850, V. 460 ; Corda, Ic. Fiinc/. i. figs. 21,
25, 2G ; Fries, Smnma Veqet. 523.

CONIOTHY'RIUM, Corda.— A genus of
Sphaeronemei (Stylosporous Fungi).

C. ylomeratum, Corda, recorded by Berke-
ley and Broome as British, is said by Fries
to' belong to his genus Cliaosporwn. It is a
microscopic plant growing in the cracks of
dead wood (elm) ; composed of minute free
membranous peridia enclosing numerous
spores, which escape by the bursting of the
apex.

BiBL. Berk, and Broome, Ann. N. H.
1854, xiii. 400; .Corda, iv. f. 208; Fries,
Siimma Veget. 522 ; Montague, Ann. Sc.
Nat. 3 p.5r. xii. 304.

CONJUGATION or ZYGO'SIS. — A
process occurring among many of the lower
plants and animals, in which the substance
of two distinct organisms comes into con-

tact and becomes fused into a single mass, or
zj'gospore. This operation is always con-
nected with reproduction in plants, some-
times also in animals.

In the vegetable kingdom it has been ob-
served in the Algae, viz. in the Zygnemaceae,
the Desmidiacepe, the Diatomacete, the Pal-
mellaceag, and in the genus Si/zygites of
Fungi; also in the Myxomycetes. It also
occurs in the zoospores. In all these cases
it consists essentially in the blending to-
gether of the contents of two distinct cells :
either by the complete fusion of two free
cells ; by the passage of the contents of
one cell into the cavity of another through
newly-formed connecting tubes ; or by the
emission of the contents of both cells into
a space between them, where the mixed
contents become enclosed in a special en-
A'elope.

The conjugation ear-
liest discovered was that
of the Zygnemacese,
which the cells of dis-
tinct filaments lying pa-
rallel with one another,
become united by late-
ral inosculation or by
cross branches, formed
by the budding out of
the walls of the cells
opposite to each other,
the protruded processes
coming into contact, co-
hering and bscoming
confluent by tlie absorp-
tion of the surfaces of
contact (fig. 137). The
cavities of the two cells
opened into one another, the contents be-
come mixed ; in Spiro-
gyra and Zygnema the
contents of one of the
cells usually travel
across into the cavit}' of
the other (P1.9. tig. 18); \
in Zygogoniinn the con-
tents of both cells collect
in the cross-piece, this
is the case also in Meso-
carpus (fig. 138) and
StaUrocarpits, in the lat-
ter of which the cross-

Zygnema cruciata.
Conjug-itin^ filaments.
Magnified 250 dia-
meters.

being thus freely

piece
enlarged.

becomes greath"
The contents
in all these cases be-
come retracted from the
cell-wall, and, secreting

, Mesocarpus scalaris.
Conjugating filaments
with spores.
Jlagnifled 200 dia-
meters.

CONJUGATION.

[ 205 ]

CONJUGATION.

Fig. 139.

special coats, boccme spores, which escape by
the rupture of the conjugated cells. InMou-
geotio (fig. 139)
there is no cross-
branch. The fila-
ments become an-
gularly bent and
inosculate at the
angles. A spore
is said to be form-
ed in each cell
here. (See Zyg-

NESr.\CEJE.)

Pseudo - spores
are sometimes
formed in the cells
of Zygnemaceae
without conjuga-
tion, in which case
they are barren.

In the Desmidiacese,
seuts a number

Mougootia genuflt'xa.

Conjugating filaments.

Magnified 100 diameters.

the process pre-
of modification?. In the
filamentous forms, such as Hyuhtheca and
Didymoprimn, conjugation does not usually
take place until the single cells of the
filaments have become separated ; but in
some cases, as in D. Borreri, conjuga-
tion of the filamentous groups has been
observed, perhaps this occurs in Des-
midium also. In Closterium, Penimn, Tet-
memorus, Costnariian, Szc, the free cells
conjugate in pairs. In ahnost all these
cases the mode of union appears to be
different from that which is seen in Zygne-
maceai ; for the external membrane dehisces
more or less completely, so as to separate the
parent-cells into two valves, while a deli-
cate internal membrane previously lining
this is protruded as a sac, to meet its fellow
from the corresponding conjugating indivi-
dual; these sac-like processes coalesce, and
thus the contents of the cell are enabled to
mix. In Hyalotheca dissUiens and Penhnn
Breh'ssom'i, there is said to be union of the
primary or outer cell-coat, as in Zyyncma.
The resulting spore or sporangium is mostly
formed in the connecting piece (Closfermm,
Cosmariitm, Tetmemorus, Hyalotheca) (Pl.lO.
figs. 1-3) ; or in one of the cells (^Didyino-
prium GreviUii, and perhaps in Desmidium).
In Closterium lincntuni it has been observed
that the corrugating cells divide completely
by constriction of their delicate internal
membrane just before conjugation, so that
the dehiscent primary membranes emit from
each parent individual a pair of little sacs,
in close appo.-ition ; and these meeting their
fellows, a double or ficin conjugation takes

place, and a pair of spores or sporangia are
formed. A gelatinous investment is secreted
around the conjugating sac-like processes,
and the spore is generally at first imbedded
in an abundant gelatinous coat. (See Des-

MIUIACE^.)

In the DiatomacetB there does not appear
to be any delicate internal membrane, like
that of the Desmidiacese, concerned in the
conjugation. The two conjugating indi-
viduals, lying near together, become con-
nected together by the excretion of a collec-
tion of gelatinous substance ; the siliceous
coats then dehisce, and the contents of the
parent-cells, escaping from the valves, meet
between them to unite into a globular mass,
which does not become a spore, but gradually
acquires the form of the parent. There is
no connecting tube here ; only the investing
gelatinous matter. In Ilhnantidiwn and
Surirella, one new individual is formed in
the conjugation (PI. 10. fig. 5) ; in Eunotia,
Cucconema, Gomphonema, and Schzonema,
the contents of the parent-cells appear to
divide traiisversely before extrusion, and
thus form a pair of new individuals in the
conjugation (PI. 10. fig. 6) (as in the case
of the spores of the Closterium lineatimi).
A peculiar condition occurs in other genera
{Cyclotella, Melosira, kc). which is supposed
to be a conjugation of the divided contents
of one frustiile. (See Diatomace^.)

Among the Palmellacese, conjugation has
been observed in Coccochloris Brehissonii
{Pabnoylosa macrococca, Braun), where two
vegetative cells become completely fused,
membrane and contents, to form a spore
which acquires a firm coat and oily contents,
and passes through a stage of rest before re-
commencing vegetative development (PI. 7.
fig.6,c,c^).

Fig. 139*.

Pandorina morum. Conjugation of zoospores.
Magnified 300 diameters.

The zoospores of Pandorina conjugate
much as in Coccochloris; they approximate
by their apices (fig. 139*, J), become fused (c)

CONJUGATION.

[ 206 ] CONNECTIVE TISSUE.

then lose their cilia, and acquire a red
colour, finally forming a resting- spore (cI).

The supposed conjugation of Yaucheria
and similar phenomena in some other Con-
fervoids, are cases of fecundation of sporangial
cells by i/y?//AY-antheridialcells;no permanent
imion taking place.

The well-known case of conjugation in
the Fungi described by Ehrenberg" in
SyzYGiTES, a genus of Mildew Fungi, is
described under that head. See also Myxo-

MYCETES.

De Bary, Tulasne, and others have ob-
served in several Fungi, as JErysijy/ie, Pyro-
nema, Feranonpora, Szc, a sexual process
which is exactly analogous to what takes
place in certain Alga^, and in the abnormal
Saprolef/nice ; the body containing the male
element coming into contact with thefemale
organ, and thus producing fruit. This pro-
cess seems rather to come under the term
copulation than conjugation.

The conjugation observed in the animal
kingdom, consists in the direct union, by a
more or less extensive, sometimes complete,
fusion of the substances of two or more dis-
tinct individuals. In Diplozoon parad<ixu7n
the two indi-\iduals become united by a
cross branch ; and the remarkable result is
that sexual organs become developed in
both bodies after this. Apparent conjuga-
tion takes place also in Actinophn/s, Aci-
neta, Gregaritia, &c. It is, howe^ er, pro-
bable that the fusion which occurs in many
of these cases is spurious, and unconnected
with reproduction.

Podophrya pyrum is one of the best in-
stances of true conjugation, the resulting
compound individual containing 8 embryos
in a single cavity common to both. The
true process has also been observed in Aci-
neta (mystacina), Vorticella {microstoma),
Paramecium, several Flagellata, &c. The
researches of Balbiani tending to show that
in many of the Infusoria the conjugation is
a true sexual process, have not been con-
firmed.

BiBL. Vegetables: Vaucher, Confer res;
Meyen, PjJan.phys. iii. 413 ; Ilassall, Ah/ce ;
Kiitzing, P/h/c. //«?.; 'R&\k, Desmid.\ Mor-
ren, Ann. 8c. Nat. 2 s(?r. v. 257 ; Smith,
Brit. Uiut. : Thwaites, Ann. N. JR. xx. and
ser. 2. i. and iii.; Braun, Pejur. (Pay 'Sb-
ciety, 166S) ; Focke, Physiol. Studien, ii. ;
Nfigeli, Atyen-Sysf. 175 ; Karsten, Pot. Zeit.
X.89; Ehrenberg VerhayuU.Naturf.Freund.
i. 98 ; Areschoug, Siced. Trans. 1853 ;
Bot. Zeit. xiii, 364 ; De Bary, Conjuyatce,

1859 ; Griffith, A7in. N. H. 2 ser. xvi. 92 ;
Carter, ibid. xvii. 1 ; Hoftmann, Phys. Bot.
ii. 155 &c. ; De Bary, Ann. Sc. N. 1866,
343 ; Tulasne, /. c. 1866, 211 ; Rostafinsky,
Bot. Zeit. 1871, 787. Animals: Kolliker,
Sieb. n. KoUik. Zeitsch. i. 1, 198 {Qu. 3Iic.
Jn. i. 98); Siebold, ibid. i. 270, iii. 62;
Stein, In/us. ; Wieynuatn's Archiv, 1849,
147 ; Nordmann, Mikr. Beitriiye, i. 56 ;
Clapar. & Laclim. Infus. ii. 222 ; Allman,
M. M. Jn. 1875, xiv."l78 ; Kent, Inf. 92.

CONJUNCTl'VA. See Eye.

CONNECTIVE TISSUE, of Animals,
sometimes called areolar or fibro-cellular
tissue.

Connective tissue is very generally dif-
fused throughout the bodies of vertebrate
animals, fiUing up the interspaces between
the various organs and structures, and
entering into the composition of most of
them.

There are several varieties.

The fibrous or areolar variety consists
essentially of white fibrous tissue, mostly
containing the elements of the yellow or
elastic tissue. The most common form of
the white fibrous element is that of minute,
delicate, transparent fibres, called fibrilltB,
with pale outlines (PI. 49. fig. 41); these
are sometimes single, at others united into
bimdles or fasciculi. The fibres as well as
the bundles sometimes pm'sue a straight
course ; at others they are elegantly curved
and wavy, interlacing in all directions, and
leaving larger • or smaller areolae or spaces
between them, the larger of which are
visible to the naked eve. The fibrillas are
about 1-40,000 to 1-20,000", and the fasci-
culi about 1-7000 to 1-3000" in diameter.
In the fasciculi, the fibres are connected by
an amorphous, transparent, gelatinous sub-
stance. Intermingled with the fibres, are
rounded, elongate, or branched cells (con-
nective corpuscles) or nucleated protoplasts,
which may be well examined in the trans-
parent laminae separating the muscles of a
frog's leg. Some of these are stationary,
hut exhibit changes of form. Others are
locomoti\ e, with ama^boid movement, and
correspond to the white blood-corpuscles.
The connective corpuscles may often be
rendered more distinct by staining with
magenta. AN'lien treated with acetic acid,
the fibres swell, become paler, and lose their
distinctness, the bundles appearing as if
fused into a gelatinous mass (fig. 29. p. ()9) ;
and round or elliptical nuclei, with their
long axes parallel to tho direction of the

CONNECTIVE TISSUE. [ 207 ]

COPPER.

fibres, are brought to view, as in PI. 49.
fig. 42.

The retiform variety consists of a very
delicate network of fine fibrils, formed ori-
ginally by the union of branched connective-
tissue corpuscles. This constitutes the
stroma of the spleen, and the lymphatic
glands. A i?till finer variety form the Neu-
roglia.

The yellow fibrous tissue occurs in the
form of fine or coarser fibres, with dark
outlines ; these sometimes run straight, or
are wuvy or reticular ; at others they are
coiled or form rings around the bundles of
the areolar tissue, or running parallel with
and between them, sometimes forming per-
forated membranes. They are best seen
when the tissue has been rendered trans-
parent by the addition of acetic acid.

In the gelatinous or mucous variety, the
intercellular substance forms a soft semi-
transparent mass, containing rounded spin-
dle-shaped or branched cells, often imited
by the branches ; it is met with in the lu-
vertebrata, as the Medusce, the integument
of the MoUusca, &c.

The truly cellular form, which is also
common among the Invertebrata, consists
of rour.d or elongate cells, with but little
intercellular substance ; it occurs in the
Articulata, the Mollusca, and in the Chorda
dorsalis.

Connective tissue consists chemically of
gelatine, which may be obtained from it in
solution by boiling ; elastic tissue consists
of elastine.

The various complex structures into the
composition of which the connective tissue
enters, as the mucous membranes, skin, fatty
tissue, &c., are noticed vmder their respec-
tive heads. Cartilage and Bone are also
considered connective-tissue formations.

Connective tissue is developed from the
embryonic corpuscles. These become elon-
gated, or fusiform, and branched. They
unite with each other, and the ends become
split into the component fibrillse of the
future tissue. But whether the corpuscles
are solid bodies or protoplasts, or true cells,
is not at present agreed upon.

BiBL. KiJlliker, Gciceleleltre ; Mulder-
Donders, PJnjs. Chem. ; Todd-Bowman,
Pkys. An. ; Drummond, Ed. Mn. Jn. 1852 ;
Rollett, Stricl-er's Ilandb. .38 ; Beale, Simple
Tissues ; Klein, Hist. ; Gegenbaur, Vergl.
An.] Frey, Hist, and the copious Bibl. ;
Kirkes-Baker, Phys. ; Rutherford, Histo-
lugy ; Waldeyer, Arih. f. mik. An, 1876,

ii. 170 (71/. M. Jn. xvi. 04) ; Satterthwaite,
Mn. M. Jn. 1870, xvi. 101 , 241 ; Flemming,
Arch. An. 8f Phys. 187(5, xii. 391.

CONOCEPH'ALUS, Hill. See Fega-

TELLA.

CONOCHI'LUS, Ehr.-A genus of Ro-
tatoria, of the family CEcistina.

Char. Animals aggregated around a cen-
tral gelatinous nucleus, and forming a re-
volving sphere ; two persistent frontal eye-
spots.

From ten to forty in each sphere. Nu-
cleus sometimes green, from the presence
of parasitic monads. Four thick conical
papillfe arise from the middle of the frontal
surface, each having a bristle at its apex.

C. volvox (PI. 43. figs. 15-17). Cara-
pace and body white, gelatinous, and hya-
line ; length 1-60", breadth of sphere 1-8".
Freshwater. 2 kinds of eggs — male and
female.

BiBE. Ehr. Infus. 393; Davis, 31. 31.
Jn. 1876, 1 : Bedwell, Jn. 3Iic. Soc. 1878,
i. 170.

CO'NODONTS.— Minute, slender, coni-
cal, curved, brownish bodies, found in a
sandy Lower Silurian clay near Petersburg,
and supposed by Pander to be minute fish-
teeth. Possibij^ they belonged to Cyclo-
stome fishes of extinct genera. They occur
also in later strata.

BiBL. Pander, 3Ion. foss. Fische, kc,
1856; Murchison, Sihiria, 1859, 375, and
1867, 350 ; Hinde, Qu. Geol. Jn. xxxv. 356,

CONOS'TOMUM, Sw.— A genus of Bar-
tramiaceous Mosses. Conostomum horealc,
Sw., on Scottish mountains.

CONULI'NA, D'Orb.— A top-shaped,
many-chambered, stichostegian Foramiuifer,
having the septal face shghtly convex and
multiperforate, is the only recorded sample
of this doubtful genus, which is probably
related to Lituola.

Bibl. D'Orb. Foram. Cuba, 1839.

CONULI'TES, Carter.— A Foraminifer
of the Glohiyerinida family, closely allied
to, if not the same as, Patellina.

Bibl. Carter, Ann. N. H. ser. 3, viii. 457 ;
Carpenter, Introd. For. 233,

COPE'PODA. See Entomosteaca,

COPPER.— Crystals of metallic copper
exist inartificial Av.\XTrEiNE. The acetate
of copper is noticed under Acetic acid.

Copper occurs in minute quantities, in
the human bile, biliary calculi, and the
blood ; and in the blood of some Crustacea :
also in the Cephalopoda.

The ammoniiu'et of copper is prepared by

COPPINIA.

[ 208 ]

COEALLIUM.

digesting copper turnings in an open bottle,
■with Liq. Amm. (P. B.) ; it must be used
fresh. Its action is well displayed when it
is brought into contact with cotton-wool.

__COPPI'NIA, Hass.— A genus of Coppi-
niidfe (Il^droid Zoophytes).

Char. Cells long, crowded, united by a
cellular mass at their bases ; ova developed
in the cavities of the cellular mass.

C arcta. Incrusting the stems of other
zoophytes, common ; greenish yellow.

BiBL. Ilassall, 3/ic. Tr. iii. 160; Hincks,
Brit. Zooph. 219.

CO'P A, Fr. — A tropical genus of Lichens,
approaching Coccocarijia.

1 species : C. pavonia.

BiBL. Fries, 8yst. Orh. Veg. 300 ; Nyl.
Ann. Sc. Nat. 1855, iii. 151.

CORAL. — A term applied in general to
the calcareous polypidom or skeleton of
Polypes or Zoophytes, and in particular to

that of CORALLIUil.

CORAL'LTNA, Linn.— A genus of Co-
rallinacete (Florideous Algse), of stony cha-
racter, looking like corals. The common
C. officinalis grows everywhere between
tide-marks, on rocks, &c. ; and presents a

Fiff. 140.

Corallina officinalis.

Fig. 140. A branch of the frond. Natural size.

Fig. Ml- Ascctionof the end of a branch terminating
in a ceramidinm, containing tctrasiiorcs. Magnified 10
diameters.

branched, mostly pinnate tuft of articulated
filaments evenly coated with carbonate of
lime. The tctraspores are borne in tufts in
ceramidia (tig. 141), usually at the apices
of the branches (being the last jomts trans-
formed) ; or they occur laterally (tig_. 140),
sometimes in pairs and sometimes irregu-
larly over the whole frond ; opening by a
small terminal pore (tig. 141).

The structure may be examined in these
plants, by keeping them for some time in
vinegar or dilute muriatic acid ; which wiU
remove the lime, and allow of the substance
being sliced in the same way as other Algfe.

BiBL. Harvey, Mar. Alg^.^\. 13 C ; Phyc.
Brit. pi. 222 ;' Decaisne, Ann. Sc. Xat.
2 ser. xvii. pi. 17. fig. 1, xviii. p. 119;
Solms-Laubach, CoruH.-Alqcn Golf KeapcL

1881. y J 1 ^

COR ALLINAX'E.-E.— A family of Flo-
ridete. Rigid, articulated, or crustaceous,
mostly calcareous sea- weeds, purple when
fresh, fading, on exposure, to milk-white ;
composed of closely-packed elongated cells
or filaments, in which carbonate of lime is
deposited in an organized form. Tetrasjwres
tufted, contained in ovate or spherical con-
ce/?;'«c/^'s(cerrt>»(V/;'a, Harvey), fiu-uished with
a terminal pore. British genera :

* Frond JiUf or m, articulated (Corallineaj).

CoraUina. Frond pinnated. Ceramidia
terminal, simple.

Jania. Frond dichotomous. Ceramidia
tipped with two horn-like ramuli.

** Frond crustaceous or foJiaccous, opaque,
not articulated (Niilliporte).

Melohesia. F-ond stony, forming either
a crustaceous expansion, or a foliaceous or
a shrub-like body.

Hildchrandtia. Frond cartilaginous, not
stony, forming a crustaceous expansion.

*** Frond plane, hyaline, composed of cells
radiating from a centre. Fructijication
unknown (Lithocysteae).

Lithocystis (a minute parasite).

CORALLINES.— The Corallinacefe, a
family of Alga?, were formerly imagined to
be of animal nature, and were classed among
the Zoophytes. On the other hand, Ellis
applied the term Coredlinc more extensively,
including under it Polyzoa (Bryozoa), and
Sertulariau and similar Zooph-s tes (Polypes);
the name is still often vulgarly used in this
sense. The term shoidd properly be re-
stricted to the family to which the genus
Corallina gives the name.

CORAL'LlUxM, Lam.— A genus of
Zoophytes, of the order Actiuozoa.

The red coral of comijierce is the intei--
nal skeleton of Corallium ruhrum, Lam.
{Isis nohilis, Lin.) (PI. 41. fig. 6 c). A por-
tion of the diied animal matter is usually

CORDYCEPS.

[ 209 ]

CORINNA.

found adhering to its surfece, and contains
aLundance of spicula (PL 41. lig. 7).

The furrows seen upon the outer surface
of unprepai-ed coi-al, are the impressions of
vessels which traverse the cortical substance
and form a medium of communication be-
tween the various polypes.

The structure of coral is rather obscure.
The ti-ansverse section (PI. 41. hg. 8 a) ex-
hibits somewhat uudetined hnes, some of
which are semicoucentric with the marginal
furrows, and appear to be lines of growth ;
these are intersected by darker and narrower
lines, apparently cauals. The orifices of
larger canals are also visible. The longitu-
dinal section (PI. 41. tig. 8 b) exhibits lon-
gitudinal lines, probably those of growth,
with an indistinct intermediate structure.
When treated with acid, the residue is soft
and easily folded so as to produce a lined
appeai-ance ; and in parts the organic skele-
tons of spicula may be distinguished. Hence
it probably consists of spicula, aggregated
and ultimately consolidated, so that their
structure is no longer distinguishable.

BiBL. Cuvier, Regne Animal, 18-53, Zoo-
phjtes ; Lacaze-Duthiers, Hist. Nat. Corail,
1864 ; Dana, Corals, 1872 ; Nicholson &
Etheridge, An. N. H. 1877, xx. 161, 388 _;
Milne-Edwards & Haime, Monoy. fossil
(Pal. Soc.) ; Duncan, ibid.

COR'DYCEPS, Fries. See Sph^ria
and Claviceps.

CORD YLO'PHORA , Allman.— A genus
of Zoophytes, order Hydroida, and family
Clavidas. Freshwater.

Char. Polypidom horny, branched, rooted
by a creeping tubular fibre ; branches tubu-
lar ; polypes existing at the extremities of
the branches, ovoid, the mouth at the distal
extremity, and furnished with scattered fili-
form teutacula.

C. lacusfris, the only species; height 2-3
inches. The only compound Polype found
in fresh water.

BiBL. Allman, ^ww. iV. ^.xiii. 330; and
P/iil. Tr. 1853 ; Johnston, Br. Zoophi/fes,
44 ; Hincks, Zooph. 15 ; Schnitzels Arckiv,
1871.

CORE'IMIUM, Link.— A spurious genus
of Mucedines (Hyphomycetous Fungi), not
really distinct from Penicillium ; but dif-
fering from the characteristic form of that
genus in having the erect fertile filaments
compacted into a kind of cellular pedicle to
bear the strings of spores (fig. 142). C. leu-
copus, Pers. ; filaments white, spores gi-een ;
not uncommon on decaying fruits, &c.=

Floccaria glauca, Grev. 8c. Crypt. Fl. t. 301,
and is Penicilliuin crastaceiuii ^, Fries. C.
candidum, Nees, filaments and spores white,

Fig.

142.

Coremium niveum, Corda.
Magnified 200 diameters.

on decaying substances, is Penicillium can-
didum /3, Fries.

BiBL. Hook. Brit. FL v. pt. 2. 344;
Fries, Si/st. Mycol. iii. 408 ; Greville, loc. cit. ;
Corda,, IconesFimy.ii. pi. 11. tig. 73; Pracht-
flora, pi. 25.

CORE'THRA, Meig.— A genus of Dip-
terous Insects, of the family Tipulidae.

The larva of C. jyJumicvrnis forms a beau-
tiful microscopic obj ect ; it inhabits fresh
water.

BiBL. Karsch, Monoy. d. Coreth. plum. ;
Ray Laukester, Pop. Sc. Bev. 1865; Ley-
dig, Sieb. 4' B^oll. Zeitsch. iii. 435 ; Rymer
Jones, Mic. Tr. 1860. 99 ; Weismaun, Sieb.
^- Koll. Zeitsch. 1866, 45.

CORE'THRIA, Wright.— A genus of
Rhizopoda, family Actinophryina ('/). Body
oblong, with a long club-shaped appendage,
bearing a thick brush of 8-40 tentacles at
its summit.

C. sej'tularice. On Scrtidaria pumila^

BiBL. Piitchard. Infus. p. 563.

CORIN'NA, Heib.^A genus of Diato-
macete.

Char. Frustides punctate-areolate, united
into semicircrdar fascife, angles produced,
spiniferous, the uppermost longest, inter-
mediate portion hemispherical, with septa ;
valves ellipsoidal, transversely bicostate,
apiculate at each end.

COEK.

[ 210 ] CORPORA AMYLACEA.

C. elegans. Shores of Denmark.

BiBL. Heiberg, Consi). Died. 1863, 53,
pi. 3. tig. 8.

CORK. — Ordinarily the outer layer of
bark of the Cork Oak ( Quercus Suber), for
the deTelopmeut of which, see Bark. Ver-
tical and trausverse sections of the large
liirht-coloured cells of cork are shown in
PI. 47. figs. 16 and 17. The term cork is
applied generally to excessive developments
of the suheroiis layer of barks.

CORN. — The general name applied to
the seeds, or rather the fruits of the various
plants furnishing the ordinary materials for
bread. These all belong to the Mouocoty-
ledonous family, Graminacese (Grasses) ; for
Buck-wheats cannot be considered as true
corn, The grains of the Grasses are enve-
loped in the adherent pericarp, which is dry
and smooth ; the seed which this encloses is
characterized by the presence of a compara-
tively larger mealy albumen, composed of
thin-walled parenchyma, more or less densely
filled with starch, which makes up the great
body of the grain ; a few layers of cells sub-
jacent to the surface, however, contain little
starch, but abundance of nitrogenous proto-
plasmic matter, or yliden. These layers
containing the greater proportion of the
gluten, together with epidermis, are removed
from fine flour in grinding, as the bran and
pollard — the fine white flour consisting
chiefly of the starch. The forms of the
starch-grains difter considerably, as also
their condition in the cell (PI. 46). In
Wheat {Tritiaim), the starch-grains are
lenticular (fig. 8), and lie loose in the cells ;
in Barley (Jfordewn) , they are very similar,
but the larger grains are squarish and
thinner (fig. 9) ; in Oats (Aveiia), polygonal,
but compacted together into roundish
masses (fig. 10) ; in Rice (Oryza) , the starch-
grains are veiy small, and packed so
closely together that they press upon one
another, thus acquiring a parenchymatous
form (figs. 12 & 13) ; and then, as they ad-
here firmly together, the contents of the cells
appear like one solid mass; hence the horny
character of the grains of rice, and the grit-
tiness of rice-flour. In Maize (Zca), the
outer part of the grain is horny from the
same cause as rice, and presents a similar
appearance (fig. 3), but in the centre the
cells are often less densely filled, and the
grains lie more or less loose (fig. S). For
further particulars of the characters of
the starch-grains, see Starch.

CORNEA. See Eye.

CORNICULA'RIA, Ach.— A genus of
Lichens = ^/ec;'o;-/« pt.

CORNS consist of thickened epidermis,
the scales being increased in number, much
flattened, and closely aggregated from pres-
sure. This is the structure in their simplest
form. When larger they represent an ordi-
nary bhster, conjoined with the thickening
of the epidermis ; hence the origin of the
cavity in the centre of many of them. The
papillfe of the cutis are generally hypertro-
phied. The epidermic scales may be ren-
dered distinct by digestion with acetic acid
or solution of potash.

CORNUSPI'RA, Schultze.— This genus,
restricted, comprises the planorbiform 3Iili-
olida, which, commencing with a somewhat
agathistegian growth, soon become discoi-
dal and non-segmented.

C.fol/acea (Pi. 23. fig. 13) is a common
Foraminifer, white and opaque, with the
whorls rapidly increasing in width in the
adult state. It has abounded from the
older Tertiary times to the present, chiefly
in shallow water, but found at 530 fathoms,
North Atlantic, by Carpenter.

BiBL. Carpenter, Foram. 68 ; Pr. Roy.
Soc. 1869; Schultze, Ann. N. H. 1861,
306.

COR'PORA AMYLA'CEA.— These are
microscopic rounded bodies, exhibiting a
number of concentric rings, and somewhat
resembling starch-grains in appearance.

They are found in
the/orau', 'Cn^septuin
lucidum, the walls of
the ventricles, and the /(
cortical substance of '
the brain, the me-
dullary substance of ^

the spinal cord, the Magnified 350 diameters-
waxy spleen, &c.
They are but little
acted upon by dilute
acids; caustic alkalies render them more
transparent, and gradually dissolve them.
Solution of iodine gives them a bluish tinge ;
and the subsequent addition of sulphuric
acid produces the bluish-violet colour seen
when cellulose is treated with these reagents.
The reaction is best seen when the action of
the acid takes place slowly. Hence these
bodies have been regarded as consisting of
amyloid or cellulose.

The corpora amylacea must be distin-
guished from the concretions forming ' brain-
sand,' or the acervulus cerebri. These are
also rounded, single, or aggregated, usually

Fig.

143.

Corjiora amylacea, from
the hiuuan ependyma.

CORPUSCULA.

211 ]

COSCINODISCUS.

exhibiting the concentric rings, sometimes
forming cylindricttl, ramified, or reticular
fibres. Tliey are met \vitli in the choroid
plexuses, the pineal gland, the arachnoid
membrane, and sometimes in the walls of
the ventricles. These consist of an organic
(proteine) skeleton, containing carbonate
and phosphate of lime. When treated with
acids, the latter are dissolved, the former
being left and retaining the original form of
the concretions.

BiBL. Purkinje, Midlers Archiv, 1836 &
1845 ; KoUiker, Mihr. An. ii. ; Virchow,
Archiv path. An. 135, 268, 416, and Ann.
N. Hist. xii. 481 ; Green, Pathology, 1871,
71 ; Frey, Histol. ; Eindfleisch, Path. 1878,
35.

CORPUS'CTJLA, of the Coniferfe. See

GVMXOSPEEMIA.

CORROSIVE SUBLIMATE, the bichlo-
ride of Mercury. — A saturated solution of
this salt is very useful in rendering very
transparent bodies consisting of proteine-
compounds more opaque and distinct, as
the bodies and cilia of Infusoria &c.

CORYC.E'US, Dana.— A genus of Cope-
poda (Entomostraca).

C. anglicits. Marine.

BiBL. Bradv, Copepoda {Ray Soc), iii.
32. "^

CORY'CTA, Duj. = Amosba bilimbosa,
Auerbach (Duj. Ann. d. Sc. N. 1852, p. 41).

CORYMOR'PHA, Sars.— A genus of
marine Hydroid Polypi, family Tubulariida^.

Bi3L. Hincks, Brit. Zooph. p. 125.

CORYNACTIS, Allman.— A genus of
Anthozoa (Zoophytes).

1 species : C. viridis.

EiBL. Gosse, Actinologia Britannica (the
latest work on Sea- Anemones).

CORYiSTE, Gfertn. — A genus of marine
Hydroid Polypi, family Corynidae.

'BiBL. Hincks, BrU. Zooph. p. 37.

C0RYN'EU31, Kunze.— A genus of Me-
lanconiei (Stylosporous Fungi), consisting
of pai'asitic plants growing upon dead twigs,
biu'sting out as convex solid pustules from
beneath the epidermis. A vertical section
of half of one of these pustules is shown
in fig. 144 ; the cellular stroma is covered
by stalked multiseptate spores. Six forms
are recorded as British. That figured,
C. disciforme, Kze., grows on dead twigs of
birch.

Tulasne states this genus to consist of the
conidiiferous form of Melanconiei (Sphaeria-
cei).

BiBL. Hook. Br. Ft. v. pt. 2. 355;

Coryneum disciforme.
Vertical section of half

a pustule.
Magnified. 200 diams.

Berk. & Broome, Ann. Fig. 144.

iV. H. 2 ser. v. 458;
Currey, Qii. Mic. Jn. v.

127; Tulasne, Ann. Sc.
Nat. 4 ser. v. 110;
Corda, Icones Fang.

CORYNO'PSIS; All-
man. — A genus of ma-
rine Hydroid Polypi,
family Hydractiniidje.

C. Alderi. Durham.

BiBL. Hincks, Brit.
Zooph. p. 34.

COSCINODISCUS,
— Ehr. A genus of
Diatomaecce.

Char. Frustrules free, single, disk-shaped;
valves circular, fiat, or sliglitly convex, ex-
hibiting a cellular or areolar appearance ;
no internal septa, nor lateral processes.

The cellular appearance arises from the
existence of depressions, which are of
different sizes. The valves form beautiful
objects.

Kiitzing enumerates forty-one species,
which are either marine or fossil. Smith
admits four British species.

C. minor, E. Depressions irregular and
crowded (circular, Sm.) ; margin of valves
smooth ; freshwater and marine ; diam.
1-1200 to 1-500".

C. radiattis, E. (PI. 51. fig. 1). Depres-
sions obscurely radiating, marginal ones
smallest ; margin of valves smooth ; marine
and fossil; diam. 1-550 to 1-180" (a, side
view ; h, front view).

C. eccentricus, E. Depressions arranged
in curved lines, with the convexity towards
the centre ; marine and fossil; diam. 1-400
to 1-200".

C. pyxidicula, Kg. (PyTidicuIa and Cras-
pedodiscus coscinodiscns, E.) (PI. 18. fig. 21).
Margin tumid, elegantly cellular, central
areola veiy fine, diminishing towards the
centre ; no umbilical star ; marginal cells
hexagonal, larger ; diam. 1-400". Fossil.
Virginia.

C. craspedodiscus, K. = Craspedodiscus ele-
gans, E. (PI. 25. figs. 7, 8). Margin of
valves tumid, elegantly sculptured, central
markings radiating ; an umbilical star
formed of 5 to 6 .oblong larger cells ? ;
diam. 1-120". Fossil. Bermuda.

C. oculus iridis. Areolae hexagonal, with
central " eve-spots."

BiBL. Ehr. Ahhandl. Berl. Ak. 1838 and
1839; id, Ber. Berl. Akad. 1840 et seq.;
Kiitzing, Bacill. and Sp. Alg. ; Smith,

p2

COSCrXOSPIRA.

[ 212 ]

COTTON.

Brit. Biat. 1 ; Wallifli, Q>t. Mic. Jn. 1860,
38 ; Greville, Mic. Trans. 1864, 9 ; 1865,
25, 43 ; 1866, 3, 78.

COSCIN OSPI'RA, Ehrenberg. — The
elongate subtype of Peneroplis, one of the
Foraminifera imperforata. It is a synonym
of Spirolina, Lamarck.

BiBL. Ehrenberg, Tr. Berlin Ac. 1839 ;
Parker and Joues. An7i. N. H. ser. 3, v. 180.

COSMAIIIUM, Corda.— A genus of Des-
midiaceae.

Char. Cells single, constricted at the
middle ; segments as broad as or broader
than long, neither sinuated nor spinous.

A peculiar swarming motion is observ-
able at times in the cell-contents of this
genus, difterent from the circulation in
Closteri^iin. From some observations by
Mrs. Thomas, it appears that the spore-ceU
divides into numerous individuals in ger-
mination.

Rabenhorst describes 77 European species.
Among the most common British species
are : —

C, pyramidatum (PL 14. fig. 18, 19 empty
cell). Oval, with depressed and truncate
ends, deeply constricted ; end view ellipti-
cal ; segments punctate, entire ; length
1-470 to 1-260".

C. hioculatum. Smooth, depressed, con-
striction producing a gaping notch on each
side ; end view elliptical ; segments subel-
liptic, entire ; sporangium orbicular, spi-
nous ; length 1-1410"'.

C. crenatum (Pl. 14. fig. 20). Punctate,
deeply constricted ; segments crenate at the
margin, depressed at the end; end view
elliptical ; spines of sporangium very short ;
length 1-470".

C. tetraophthalmum('P\.\A.?i.^.'22). Deeply
constricted ; segments semicircular ; end
view elliptical ; rough with pearly granules,
which give a crenate appearance to the
margin ; length 1-2:30".

C. manjaritifernm (PI. 14. fig. 21).
Rough with pearly granules, whicli are as
broad as long ; end view elliptic ; segments
semicircular or reniform ; length 1-500 to
1-300".

C. ornatum. Segments twice as long
as broad, rough with granules giving a
dentate appearance to the margin ; end view
with a truncate projection on each side;
length 1-610".

C. cucurhita. Punctate, constriction slight,
ends rounded ; transverse view circidar;
length 1-580".

Lob b describes an extraordinary species,

C. radiatnm, the surface being covered by
densely crowded hyaline filaments, like
those of Actinophrys, but closer.

BiBL. IX&lis, Desmicl. dlk2\2; Thomas,
Mic. Tr. new ser. iii. 33 ; Lobb. Qu. Mic. Jn.
1866, 55 ; Archer, Qu. Mic. Jn. 1860, 235,
1864, 178.

COSMIOBIS'CUS, Grev.— A genus of
fossil Diatomacese.

Char. Frustules simple, disk-shaped ;
valves radiato-punctate or areolar, with
linear radiating spaces (no processes nor
internal septa). 3 species : in Monterey
and Barbadoes deposit.

BiBL. Greville, Qn. Mic. Jn. 1866, 79.

COSMOCLA'BIUM, Breb.— A genus of
Desmidiacete (Palmellacete, Rab.).

Char. Cells rounded, compret^sed, deeply
constricted, attached to a branched stipes.
Reproduction by gonicUa.

C. pulchdJum (PI. 51. fig. 38), attached ;
in turfy pools.

2 other species (unattached).

BiBL. De Brebisson, Lisfe d. Desm. 133;
Rabenhorst, Fl. Alq. iii. 53.

COTHURNIA, Ehr.— A genus of Infu-
soria, of the family Vorticellina, subfamily
Ophrydiua.

Char. Solitary ; carapace urceolate,
stalked, fixed by the posterior extremity.

An anterior ring of^ cilia is present. The
body contracts suddenly, like that of Vorti-
cella.

Dujardin unites this genus with Vagini-
cola.

C. imberhis, E. (PI. 32. fig. 20). Stalk
much shorter than the hyaline carapace ;
body yellowish : aquatic ; length of carapace
1-280". Found upon Cyclops qiiadricvrnis.

C. maritima, E. Stalk much shorter
than the carapace ; body whitish, hyaline ;
length of carapace 1-570". On Ceramium.

C. havniensis, E. Stalk much longer
than the carapace ; body whitish; length of
carapace without the stalk 1-280", stalk
twice this length. On Scrtularice iSrc.

Stein adds 3 species, C, Sieboldii, C.
astaci, and C. curva ; found upon Astacus
Jliiviatilis (the Cray-fish), CI. & L. de-
scribe 12 species, 4 new.

BiBL. Ehr. Inf. 297; Duj. Inf. 564;
Stein, Infus. ; Clap. & Lachm. Infns. i.
121 ; Kciit, /«/. 719 ; Ilutton, Jn. Mic. Soc.
1878, i. 49.

COTTON.— The hairs from the epidermis
of the seeds of various species of Gossypium
(Malvacepe, Dicotyledons). These hairs are
readily distinguished imder the microscope

COVERS.

[ 213 ]

CRIBRAKIA.

from the various textile fibres consisting of
liber structures. From the abseuce of the
regular thiekouiug layers, the cells of the
cottoD-hairs bect)me collapsed when dry,
appearing like a flat baud with thickened
borders, while liber-cells of all kinds re-
main cylindrical, and taper to a point at
each end (PI. 28. fig. 1). See iiBuous
STRUCxniES ; and Mitchell, Qu. Mic. Jn.
18G4, 218.

COVERS. See Ixtroduction, p. xxiv.

CRASPEDODISCUS, E.— A genus of
fossil Diatomaceoe.

C. coscinodisciiSy '£,.-= Pyxidiciila coscino-
discm, 'E.= Coscinodiscus 2)i/xidicula, Kg.
(PI. 18. fig. 21).

C. eleyans, E. = Coscinodiscus craspedodis-
cm, Ko-. (PI. 25. figs. 7 & 8).

BiBL. Ehr. Ber. d. Berl. Ak. 1844, 261-
2r,6; Kiitzing, Sp. Alq. 126 ; Greville, Mic.
Trans. 1866, 79; Pritchard, Inf. 831, 939.

CRASPEDO'PORUS, Grev'.— A genus
of Diatomaceae.

Char. Frustules free, di>k-shaped ; valves
with club-shaped rays, each with an ocellus
near the margin.

C Half's ianus. Valves areolar, rays 8;
diam. 1-220". Barbadoes.

C. Johnstonianus, Rays 5 ; diam. 1-400".
Barbadoes.

BiBL. Greville, Mic. Trans. 18G3, 68.

CRATERIUM, Trent.— A genus of
Myxomycetes, consisting of minute yellow
or' brown cup-like bodies, of papery con-
sistence, closed by a deciduous operculum
(fig. 145) ; arising

from an evanes- Fig. 145.

cent gelatinous
mycelium, gTow-
ing over moss
leaves, bark, c&c
Most of the spe-
cies are common.
The black spores
contained within
these cups are
intermixed with crowded, obscurely arti-
culated filaments (destitute of spiral fibres),
which do not anastomose, and are at length
erect. Five British species. A. Murray's
remark upon Craterium, that it is an
Acarus, applies to Afractubolus.

BiBL. Hook. Brit. Fl. v. pt. 2. 316;
Sowerby, Func/i, t. 239 (C. minutum, as
Cijathuti minutu&).

CRATEROSPER'MUM, Braun.— A ge-
nus of Zyg-nemacese, with the green endo-
chrome not in spiral bands. Conjugating

Craterium pyriforme.
Magnified 10 diameters.

filaments geniculate ; sporange or zygospore
with a double cyst ; the inner spherical, the
outer thick, shortly cylindrical, subf^uad-
rate, with an annular furrow, and ex-
cavated at each pole.

6'. laievirens (PI. 3. fig. 10). In pools.

BiBL. Braun, Alg. tlnicell. 1855, 60;
Rabeuhorst, Fl. Alg. iii. 258 (fig.).

CREATINE or' KREATINE.— Occurs
in the juice of the flesh of Mammals, Birds,
Amphibia, and Fishes; in exudations, in the
amniotic liquid, the blood, and the brain.
It crystallizes from an aqueous solution, in
transparent, highly refractive, oblique-rhom-
bic prisms and needles (PI. 11. fig. 22) be-
longing to the oblique-rhombic prismatic
system.

CREATINIXE or KREATINIXE.—
Occurs in the lU'ine of man and of Mam-
malia. The crystals form colourless prisms
belonging to the oblique-rhombic prismati
system (PL 11. fig. 23).

Creatinine forms a crvstallized cnmpiiund
with chloride of zinc (PI. 11. fig. 24). This
is very difficultly soluble in water, and not
at all in alcohol or ether.

CRE'NOTIIRIX, Cohn.

-A genus

of

Oscillatoriacefe (Confervoid Algfie).

CJiar. Filaments narrow, jointed, ar-
cuate or twisted into little free or ad-
herent tufts ; with hyaline sheaths ; endo-
chrome homogeneous; sporanges terminal.
Microgonidia formed from a row of cells by
successive division, rounded, very minute,
crowded, and without cilia. Macrngonidia
of the entire or 2-4-divided ceU-contents.
Intermediate between Lynyhya and Cha-
incpsiphon.

C. polyspora. In wells and springs.

BiBL. Cohn, Beit. Biol. i. 108.

CRESS WEL'LIA, Grev.— A genus of
fossil Biatomaceae.

Char. Frustules cylindrical, cohering by
short filiform (spine-like) processes into a
continuous filament. Valves cup-like, are-
olar, destitute of siliceous connecting band
or hoop.

C. turris. Clvde. Other species.

BiBL. Greville, Edin. Ph. Tr. 1857, xxi.
5.S8; Mic. Tr. 1801, 68; 1865, 4; 1806,
78.

CRIBRA'RIA, Schrad.— A genus of
Myxomycetes (Gasteromycetous Fungi),
consisting of minute stalked capsules grow-
ing upon rotten wood kc. The capsules
(peridia) are mem1)ranous ; the upper part
falls or decays oft' when the spores are
mature ; and the anastomosing filam n ts

CRIBRILINA.

[ 214 ]

CRONARTIUM.

(capillitium) ^vliicli ai-e contained in the in-
terior, are coufluent witli the outer wall,
where they lorm a permanent spherical
cage or network (fig. 147), from the meshes
of which the spores escape. The tliree or
four species recorded as British, are C.
intermedia, Berk.,

intermediate be-
tween C. vulr/ai-is
and C. anrantiaca.
The peridium is
yellow with a white
stalk ; the spores
yellow. (Figured
as SpJi(rrocarpus
semitrichioides by
Sowerby, t. 400.
fig. 5.) To this
have recently been
added C. ariiiUa-
cea, aurantiaca, and
intricata. They are
very interesting
microscopic ob-
jects.

BiBL. Hook.
Brit. Fl. V. pt. 2.
318; Fries, Syst.
Mycoloy. iii. 1(JS ;
Cor da, Icon. Fung,
V. pi. 3. tig. 35;
Cook, Handb. 400.

CRIBRILFNA,
Gray. — A genus
of Cheilostomatous

Fig. 146.

Cribraria aurantiaca.
Natural size.

Fis:. 147.

Cribraria aurantiaca.

PolyZOa(BryOZOa), Peridium burst, with the ca-
= LepraUce with piUitium exserted.

the front cells OC- Maguified 25 diameters.

cupied by transverse or radiating punctured
furrows. 5 species. On shells and Algee.

BiBL. Hincks, Polyzoa, 184.

CRICKET. See Acheta.

CRIS'IA, Lamx. — A genus of CrisiidiB,
Cyclostomatous Polyzoa.

Char. See CnisiiD^. Three species.

C. cornuta. Cells curved, orifices turned
one way ; a long bristle above each cell.

C. eburnea. Cells loosely aggregated,
curved, ends free. Common.

C. denticidata. Cells loosely aggregated,
nearly straight, joints black.

CRISIID/F.— A family of Cyclosto-
matous Polyzoa.

Distinguished by the plant-like jointed
and branched calcareous polyzoary and the
tubular cells in one or two rows, with
round orifices mostly looking to opposite
sides.

Cells and branches covered with dots
Pear-shaped vesicles are met with on the
polypidom, resembling those of the Sertu-
lariidaB.

Crista. Cells in one or two rows, sub-
alternate ; orifices terminal and entire.

BiBL. Johnston, Br. Zooph. 382 ; Hincks,
Poh/zoa, 418.

CRISTATEL'LA, Cuv.— A genus of
Cristatellidse, Polyzoa (Bryozoa).

Char. Polyzoary free, disk-shaped, poly-
pifcrous at the margin; tentacles numerous,
pectinate upon two arms. Freshwater.

C. imicedo (PI. 41. fig. 9). Three, four,
or more polypes arise from the locomotive
polypidom. Pseud-ova (stato blasts) in the
young state enclosed in a ciliate membrane,
clisk -shaped, fm-uished with marginal spines
Avhieh are hooked at the end (fig. 10), and
opening with a lid.

In clear lakes and ponds, creeping over
stones and the stems of aquatic plants ; and
occasionally in large numbers in the holes
made bv the feet of cattle aroimd ponds.
Length'l^", breadth J".

BiBL. Cuvier, Beyne Animal, 1817, iv.
68; Turpin, Ann. d. Sc. Nat. 2 ser. vii. 65;
Gervais, ibid. vii. 77 ; Johnston, Br. Zooph.
387 ; Varley, Lond. Phys. Journ. iii. 37 ;
Allman, Poh/zoa {Bay Sac).

CRISTELLA'RIA, Lamk.— Among the
hyaline Foraminifera grouped generically
as Xodosarina and varying in mode of
growth from straight and partially curved
to discoidal, the Cristellarics are the more
symmetrically lenticular and uautiloid, vary-
ing, however, in outline and in thickness.
The chambers, either triangular or falciform,
iire close-set and communicate at the outer
angle. The shell is neat, often delicate,
and ornamented on the margin with keel or
crest, and on the sides with raised unibones,
granulations, cross bars, and septal ridges.

Cristellaria is common in the Lias and
all succeeding formations, very large in the
Tertiary deposits of Italy, and not uncom-
mon in existing seas. C. simplex (PI. 23.
fig. 34), feeble of growth, is present always
with other Cristellarics. C. cnlfrata (fig. 37)
is a A\'ell-grown and typical form.

BiBL. D'Orbiguy, For. Foss. Vien. 62;
Morris, Brit. Foss. .33 ; Williamson, Bee.
For. 24 ; Parker and Jones, Ann. N. H.
2 ser. xix. 200; 3 ser. iii. 477; v. 114; Car-
penter, Foram. 1()2.

CRONAR'TIUM, Fries.— A genus of
Urediiiei (Coniomycetous Fungi), present-
ing the most perfect form of structure in

CROUANIA.

[ 215 ]

CRUSTACEA.

tlint family. The spores are contained in
a peridiiim, which bur.sts by a regular or
irregular apical orific(\ The perfect spores
are produced on a columnar cellular body,
called the ligule, which rises out of the
centre of the Uredo-form or of its empty
peritheciuui. C. Vincetoxici is the perfect
form of Uredo Vincetoxici.

BiBL. Tulasne, Ann. Sc, Nat. 4 ser. ii.
188.

OROUA'NTA, J. Agardh.— A genus of
Cryptouemiaceae (Florideous Algaj). C.
atteniutfa is a very rare plant, which has
been found epiphytic on Cladostephus spon-
giosus. Its frond consists of a single-tubed
jointed filament, with the joints clothed
with dense whorls of minute dichotomously
multiplied brauchlets, somewhat beaded.
The favellidia are stated to occur near the
tips of the branchlets; the tetraspores (large)
are affixed to the bases of the latter.

BiBL. Harvey, Mar. Alg. pi. 21 D ; Phyc.
Brit. pi. 106 ; J. Agardh, Akj. Medit. 83 ;
Agardh, Sp. Alg. ii. 136 (as Grijfithsia
nodulosa) ; Kiitzing, Sp. Alg. 651 (Calli-
thamnio7i).

CRUCIB'ULUM, Tulasne.— A genus of
Nididariacei (Gasteromycetous Fungi).

C. vtdgare occurs frequently on ferns, de-
cayed sticks, itc, and is found in many
parts of the Avorld.

BiBL. Sachs, Bot. Zeit. xiii. 833; Tulasne,
Ami. Sc. N. 1844.

CRUCILOCULI'NA, D"Orb.— A Trilo-
culine Miliola with a crucial fissure for its
aperture — that is, having four small symme-
trical valves, instead of one. Known only
from the Patagonian coast.

BiBL. D'Orb. For. Amer. Mer. 1839;
Carpenter, Introd. For. 80.

CRUME'NULA, Duj.— A genus of In-
fusoria, of the family Thecamonadiua.

C7>ar. Oval, depressed, with a resisting
obliquely striated or reticulated tegument,
from a notch in the fore part of which a
long flagelliform filament issues ; a red eye-
spot. Movement slow.

C. testa (PL 30. fig. 34). Green ; aquatic;
length 1-510". Filament three times as long
as the body.

Dujardin appends Prorocentrwn, E., to
this genus.

BiBL. Duiardin, Infus. p. 339.
CRUOR'iA, Fries.— A genus of Crypto-
nemiacese (Florideous Algae). C. 2)efHla is
common on exposed rocks and stones be-
tween tide-marks, forming a glossy purplish
skin, between gelatinous and leathery, upon

smooth surfaces, in patches 2 to 3" in dia-
meter. This ' skin' is formed of vertical tufts
of simple articulated filaments imbedded
in a gelatinous matrix. One of the cells of
each filament is larger than tlie rest. The
tetraspores occur at the bases of the fila-
ments.

BiBL. Harvey, Mar. Alg. pi. 20 C ; Bliyc.
Brit. pi. 117.

CRUSTA'CEA.— A class of Animals,
belonging to the subkingdoni Articulata.

Char. Apterous ; no trachea) ; respira-
tion aquatic (branchial), or effected by the
skin: legs jointed. A dorsal vessel, ven-
tricle, or heart; integument composed partly
of chitiue.

The integument of the Crustacea usually
forms a hard calcareous shell, sometimes,
however, being leathery or horny ; it con-
stitutes an external skeleton. In its most
complex condition four layers are distin-
guishable : — an outermost, very thin, trans-
parent, and structureless or cellular — the
epidermis ; beneath this, a layer of pig-
ment-cells to which the colour is owing, but
sometimes the pigment is not contained
within cells ; under this is a thick layer,
forming the greater part of the substance of
the integument, impregnated with calca-
reous salts, and frequently furnished with
direct prolongations in the form of tubercles,
spinous appendages, or hairs. See Shell.
The innermost layer consists of a delicate
fibrous coat, corresponding to an internal
periosteum or true skin ; it plays an im-
portant part in the moulting process [ecdy-
sis) which the Crustacea undergo, probably
secreting the new layers of the integument.
The higher Crustacea (the Decapoda)
have mostly two pairs of antennfe.

The oral organs consist of a transverse
labrum or upper lip ; beneath which is a pair
of powerful toothed mandibles, acting late-
rally, and furnished with palpi. Next come
two pairs of maxillpe ; the first are membra-
nous and hairy at the margin, but without
palpi ; the second are also membranous and
hairy, and correspond to the labium of In-
sects. Between the mandibles and the first
pair of maxillie is sometimes situated a soft,
tongue-like, sometimes cleft appendsge.
The oral organs undergo various modifica-
tions in the lower Crustacea ; these will be
considered under the respective heads. Be-
hind these are three pairs of secondary or
auxiliary jaws, or rather legs converted into
jaws, and comparable to the six legs of In-
sects ; these are furnished externally with

CEUSTACEA.

[ 216 ]

CRYPTOMOXADDsA.

palpi, Next follow five pairs of true tho-
racic legs, heLind which are five pairs of
false or abdominal legs.

The Tokmtary muscles of the Crustacea
are transversely striated.

The eyes are either simple : consisting of
a convex cornea, behind which is a rounded
refracting body or lens ; this lies in a cup-
shaped mass of pigment, perforated by the
optic nerves ; — compound without facets :
consisting of a smooth cornea, behind Avhich
a number of closely-placed eyes are situ-
ated ; sometimes a modification of this form
occurs, in the existence of a smooth outer
and an inner faceted cornea ; — or compound
faceted : as in the eyes of insects. The
facets are frequently four-sided, but some-
times six-sided. In some of the eyes a
conical vitreous body is situated behind the
lens. The eyes are sometimes sessile, at
others stalked.

The alimentxiry canal is usually short and
nearly straight, sometimes curved or coiled.
Its wall consists of three or four layers, —
the outermost, more or less fibrous,' repre-
senting a peritoneal coat ; the innermost, a
transparent, structureless, epithelial coat,
furnished at the part corresponding to the
stomach with calcareous teeth, scales, or
hairs, and which is thrown oS^ during the
ecdysis. Between these two coats is a layer
of smooth muscular fibres.

The liter exists either in the form of sim-
ple follicles surrounding the alimentary ca-
nal ; of branched eoeca situated at its upper
end, sometimes with short ducts ; or as two
glandular tufts or branches, consisting of
more or less ramified and closely-connected
caeca, with short ducts.

In many of the Crustacea the walls of the
alimentary canal are surrounded by cells
containing a bright orange-yellow or blue
fatty matter ; these are either scattered or
arranged in the form of lobules. They cor-
respond to the fatty body of Insects.

The Crustacea undergo remarkable meta-
morphoses, the larvae diflering strikinsrly
from the adults ; and to these, special names
were applied, being considered as distinct
genera: as Nauplius, Zo'ea, and Meyalopa.

See AsELLUs, Cirripedia, Entomos-
TRACA, Gammaeus, 0^'ISCTJS, and Sipho-

NOSTOMA.

BiBL. That of AxiMAi. Kingdom, and
the Bibl. of the articles just cited; Gegen-
baur, I'ercjl. Anat. 247; Schultze {eyes), Qu.
Mic. Jn. 1868, 17.:} ; Chatin, Compt. Eend.
1876, Ixxxiii. 1052 {M. M. Jn. xvii. 92) ;

Bell, Stalk-eyed Brit, (figs.) ; Bate and West-
wood, Sessile-eyed.

CRYPH.^ A, Mohr. =PiLOTRicnrir.

CRYPTOCOC'CE^E.— One of Kiitzing's
families of Algae, including hisgenera Cryp-
tococcus, Ulrina, and Sphcerotihis, all of
which appear to be forms of the mycelia
(conidia ?) of Mildew Fungi ; they consist
of masses of extremely minute colourless
globides, aggregated into a membranous or
mucous stratum, and found floating in
aromatic waters, vinegar, &c.

CRYPTOCOC'CUS, Kutz. See Cbyp-

TOCOCr'FJE

CEYPTOGA'ML^.— This term was ap-
plied by Linnaeus to his 24th Class, which
included all plants in which no true flowers
exist ; the name signifying that the sexual
organs are hidden. In Natural Arrange-
ments of the Vegetable Kingdom the term
is often used in the same sense ; but in this
case as one of two great divisions, being
opposed to Phanerogamia or Phaeuogamia,
which are plants with the sexual organs
conspicuous. See Vegetable Kixgdoji.

CRYPTOGLE'NA, Ehr.— A genus of
flagellate Infusoria, of the family Crypto-
monadina.

Char. Free ; a red eye-spot ; carapace a
scutellum, rolled in at the margins, without
a neck. Freshwater.

C. conica (PL 30. fig. 35 a). Conical,
expanded, and truncate in front, posteriorly
subacute; bluish green; length l-lloO";
two flagelliform filaments.

Cpigra (PI. 30. fig. 35 6). Ovato-sub-
globose, emarginate in front : gi-een ; length
l-lloO". {Chloromonas, Kent.) Motion
slow : filament single.

C. ccerulescens. Ellii^tic, depressed, emar-
ginate in front ; bluish green ; length 1-GOOO";
motion rapid ; no cilia distinguished.

Carter adds 3 species.

Bibl. Ehr. Infvs. 46 ; Duj. Infus. 333 ;
Carter, Ann. N.II. 1858, ii. 253;" 1859, iii.
18; Pritchard. Infus. 509; Kent, Inf. 419.

CRYPTOGRAxM'MA, Brown.— A genus
of Pteridea) (Polypodiaceous Ferns).

Char. Sterile and fertile fronds usually
different ; sori terminal on the veins, at
first separate and rounded, then confluent;
indusium formed of the involute margin of
the froiid.

C. crispa. British.

Bini,. Hooker, Sipi. Fil. 144.

CRYPTUMOXAJJI'NA, Ehr.— A family
of Infusoria.

Char. An envelope or carapace, either

CRITTOMONAS.

[ 217 ]

CRYPTONEMIACE^.

soft or hard ; no ajipendagres (organs of mo-
tion, D.) except anterior cilia, or one or
more fiagelliform filaments ; form constant.
(Envelope insoluble in potash ?)

These organisms do not adn)it colouring-
matters, hence they should probably be re-
ferred to the Algaj. One or more cilia or
fiagelliform filaments have been detected in
all the genera but one (Lm/eneUa).

The family corresponds very nearly with
the Thecamonadina of Dujardin.

No eye-spot.
Carapace with a distinct tooth in front Prorocentrum .
Carapace without a tooth Cryptomonas.

E}-e-spot present.

Carapace with a nock Lagenella.

Carapace without a neck : —

Carapace a scutoUum Crt/pfoglena.

Carapace not a scutellum Trachelomonas.

Dujardin adds the genera Phociis, D. {\n-
c\\\Cti\\g Eu(/le)ia,T^. in part), CrumenuJa, D.,
Diselmis, D., Clami(loinonas,^.,Plceotia,J),,
Anisonema, D. (including Bodo (jrandu, E.,
and 0.vyrr/ns,D. = Prorocentrum: E.); and
appends doubtfully Chatoglena, E., and
Chcctotyplda, E.

See Thecamonadina, Ophidomonas, and
Peotococcus.

BiBL. Ehrenb. Infus. 38 ; Duj. Infus. 32-3.
CRYPTOMOXAS, E.— A geniis of In-
fusoria, of the family Cryptomonadina.

Char. No eye-spot ; carapace without an
anterior tooth. Dujardin says : Globular or
slightly depressed ; secreting a membranous
flexible carapace, and furnished with a very
delicate fiagelliform filament.

Ehrenberg admits seven species ; and to
these Dujardin adds two.

C. ovata, E. (PI. 30. fig. 36 a) ; length
1-570" ; freshwater.

C. lentkularis, E. (PI. 30. fig. 36 b) ; length
1-1730" ; freshwater.

a fitsca, E. (PI. 30. fig. 36 c) ; length
1-1500"; freshwater.

a (/lobuhis, D. (PI. 30. fig. 36 d) ; length
1-2500" ; freshwater.

a incBqualis, D. (PL 30. fig. 36 e) ; length
1-2500" ; freshwater.

Dujardin appends Cryptoglena, E., and
LaqeueUa, E., to this genus.

BiBL. Ehr. Inf. 40 j Dujardin, Inf. 329;
Kent, Inf. 404.

CRYPTONEMIA'CE^.— A family of
Floride?e. Purplish or rose-red sea-weeds,
with a filiform or (rarely) expanded, gela-
tinous or cartilaginous frund, composed
wholly or in part of cylindrical cells con-
nected together into filaments. Axis formed
of vertical, periphery of horizontal radiating

filaments. Fructification: — 1. Concep-
tades (favellidia), forming globose masses of
spores immersed in the frond or in swell-
ings of the branches. 2. Ji2('?-rt.s;jores variously
dispersed. 3. Antheridia (Nemaleon).

Subtribel. CoccoCAiirE.TS. Frond solid,
dense, cnrtilaf/inous or horny. Favellidia
contained in semi-external tubei'cles or sioell-
ings of the frond.

Grateloiipia. Frond pinnate, flat, nar-
row, membranaceo-cartilag-inous, of very
dense texture. Favellidia immersed in the
branches, communicating with the surface
by a pore. Tetraspores scattered.

Gelidimn. Frond pinnate, compressed,
narrow, homy, of very dense structure.
Favellidia immersed in swollen ramuli.
Tetraspores forming subdefined sori in the
ramuli.

Giyartina. Frond cartilaginous, cylin-
drical or compressed ; its flesh composed
of anastomosing filaments, lying apart in
firm gelatine. Favellidia contained within
external tubercles. Tetraspores massed to-
gether in dense sori, sunk in the frond.

Subtribe2. SpoNCiioCARPE.^. Frond so-
lid, dense, cartilaf/inoi/s or horn^. Favellidia
of several, imperfectly hnoion. Wart-like
swellings coinposed of Jilaments ; sometiynes
containing tetraspores, sometimes spores.

Chondrus. Frond fan-shaped, dicho-
tomously cleft, cartilaginous, of very dense
texture. Tetraspores collected into sori, im-
mersed in the substance of the frond.

PhyUophora. i^/-o»f? stalked, rigid, mem-
branaceous, proliferous from the disk,
of very dense structure. Tetraspores in dis-
tinct superficial sori, or in special leaflet-
like lobes.

Peyssonelia. Frond depressed, expanded,
rooting by the under surface, concentrically
zoned, membranous or leathery. Tetra-
spores contained in superficial warts.

Gymnogongrus. Frond fihform, dicho-
tomus, liorny, of very dense structure.
Tetraspores strung together, contained in
superficial wart -like sori.

Polyides. Foot scutate. Frond cylin-
drical, dichotomous, cartilaginous. Favellm
contained in spongy external warts. Tetra-
spores scattered through the peripheric stra-
tum of the frond, cruciate.

Furcellaria. Foot branching. Frond
cylindrical, dichotomous, cartilaginous. Fa-
vellcp. imknown. Tetraspores deeply im-
bedded among the filaments of the periphery,
in the swollen pod-like upper branches ox
the frond, transversely zoned.

CPtYPTOXEMIACE.E.

[ 218 ] CRYSTALLOGRAPHY.

Subtribe 3. Gastrocarpe^. Frond
yelatinously membranuceoKs or Jiesliy, often
of lax structure internaUy. Favellidia im-
mersed in the central substance of the frond,
very mimerous.

Dumontia. Frond cylindrical, tubular,
membranaceous. Tufts of spores attached
to the wall of the tube inside.

Hahjmenia. Frond compressed or flat,
gelatinoso-membranaceous, the membra-
nous surfaces separated by a few slender
anastomosing filaments. Masses of spores
attached to the inner face of the membra-
nous wall.

Ginannia. Frond cylindrical, dicho-
tomous, traversed by a fibrous axis ; the
wall membranaceous. Masses of spores
attached to the inner face of the membra-
nous wall.

Kallynienia. Frond expanded, leaf -like,
fleshy-membranous, solid, of dense struc-
ture. Favellidia like pimples, half im-
mersed in the frond, and scattered over its
surface.

Iridaa. Frond expanded, leaf-like, thick,
fleshy-leathery, solid, of dense structure.
Favellidia wholly immersed, densely
crowded.

Catenella. Frond filiform, branched,
constricted at intervals into oblong arti-
culations j the tube filled with lax fila-
ments.

Subtribe 4. Gloiocladie^. Frond
loosely gelatinous ; the filaments hjiny apart
from one another, surrounded by a copious
gelatine. Favellidia immersed among the
filaments of the periphery.

Cruoria. Frond crustaceous, skin-like.

Kaccaria. Frond filiform, solid , cellular ;
the ramuli only composed of radiating free
filaments.

Gloiosiphonia. Frond tubular, hollow ;
walls of the tube composed of radiating
filaments.

Nemaleon. Fronds filiform, solid, elastic,
filamentous ; the axis composed of closely-
packed filaments ; the periphery of monili-
f jrm free filaments.

iJadresnaia. Frond filiform, solid, gela-
tinous, filaiuentous ; the axis composed of
a network of anastomosing filaments; the
periphery of moniliform free filaments.

Crouania. Frond filiform, consisting of a
jointed filament, whorled at the joints, with
minute, multifid, gelatinous ramuli.

BiBh. Harvey, Marine Algce ; Derbes et
Solier, Ann. Sc. Nat. 3 ser. xiv. 273. See
also the Genera.

CRYPTOS IPHUM, Buckt.— Agenusof
Aphidae.

Char. Cornicles none or mere pores;
Cauda small ; antennae with 7th joint short.

C. Artemisice. Brown or blackish, very
mealy; eyes reddish. On Artemisia vulgaris,
deforming and colouring the leaves.

BiBL. Buckton, Aphides, ii. 145.

CRYPTOSPO'RIUM, Kze.— A genus of
Sphferonemei (Stylosporous Fungi). Mi-
croscopic Fungi growing upon bark and
leaves, producing spindle-shaped spores, at
first conglutinated beneath the epidermis of
the nurse-plant. Two species have been
recorded as British.

C. Caricis, Corda. Heaps of spores
punctiform; spores slightly curved, dark
brown and pellucid. On leaves of various
sedges. Corda, apud Sturm, DeutscM. Flor.
t. 1.

C. vulgare, Fries. Heaps confluent ;
spores curved, black ( subhyaline) . On dead
twigs of birch, hazel, alder, &c. Corda, /. c,
t. li.

Bfbl. Berkeley and Broome, Ann. N. H.
2 ser. V. 371 ; Fries, Syst. Myc. iii. 481.

CRYPTOSTE'GIA, Reuss.— A gToup of
hyaline Foraminifera, having an Agathiste-
gian or Miliohne mode of gi'owth, compri-
sing Chilosfojnella and Allomorphina, Reuss,
and probably Ellipsoidina, Brady. These
are near allies of Sphceroidina, and there-
by related to Pullenia and Globigerina.
Chilostomella has successive chambers,
almost entirely overlapping (jne another, as
in Biloculina, but with a hyahne, and not
a porcellaneous shell. Allomorphina is
triloculine.

Recognized in Cretaceous and Tertiary
strata, and in existing oceans.

BiBL. Reuss, Sitzungs. Ahad. Wien,
18G1, xliv. 372 ; Bradv, Qu. Mic. Jn. xix.
66.

CRYSTALLINE LEXS. See Eye.

CRYSTALLOG'RAPHY.— The laws of
crystallography teach us that in perfectly
formed crystals, each peculiar chemical ccm-
bination corresponds to a distinct relation
of all the angles which can possibly arise
from the primary form ; hence by" ascer-
taining the latter, we can usually infer the
former. It was our intention to have given
a sketch of the method of determining the
primary forms of the more common micro-
scopic crystals, and the systems to which
they belong ; but our space is far too limiti d
for this purpose, and the subject is so difii-
cult, that we must rest satisfied with a re-

CRYSTALLOIDS.

[ 219 ]

CTENOSTOMATA.

ference to works specially devoted to tlie
subject.

BiBL. Schmidt, Untw. ein. allff. Untersuch.
8,-c. ; Robin aud ^'el•deil, Chimie Anatom.
SiC ; Phillips, Intr. to Mineral. (Brooke
aud MilK>r) ; Daua, Mineral. ; Nauiuaun,
Elem. d. Min. ; Nicol, Man. of Miner. ;
Rammelsberg, Kri/stallkunde ; Niigeli &
Schwendener, Mikr. 478.

CRYSTALLOIDS.— These bodies have
beennoticed under Chalk aud Coccoliths.
The term has been more recently ex-
tended to certain bodies formed of the
protoplasmic contents of vegetable cells,
Tvhich assiuue crystalline forms, and exhibit
the facets aud polarizing properties of
crystals, yet possess resemblances to organic
cell-structures. They are usually colourless,
sometimes coloured, the colouring matter
being removeable. They swell with re-
agents, and consist of two substances of
different solubility. Thev are found in the
cell-nuclei of Lathrea, the cells of the sldn
of the potato, in seeds, and in aleurone-
grains (page 28, fig. Qb).

So that we now have .3 kinds of crys-
talloids : Ehrenberg's chalk- and concre-
tionary crystalloids ; the vegetable crystal-
loids ; and Graham's (dialytic) crystalloids
= true crvstalline mattex-.

BiBL. ' Hartig, Bot. Zeit. 1856_, 262 ;
Badlkofer, Kryst. prot. 1859 ; Naseli, Bay.
Ak. 1862, 23.3; Sachs, Bot. 50;"Rodweil,
Diet. Sc. 162.

CRYSTALS. — Crystals are constantly
met with in the examination of animal
and vegetable products ; and the determina-
tion of their nature or composition is often
of great importance.

There are five methods of ascertaining
this : 1, by ascertaining the atomic weight
of the substance, or by its quantitative ana-
lysis ; 2, by tjie study of its crystallographic
properties ; 3, by its qualitative analysis ;
4, by its spectroscopic analysis; 5, by its
polariscopic analysis.

The first l)elongs to the domain of che-
mistry, and reqiures an appreciable quantity
of substance.

The second requires well-formed crystals,
and a knowledge of crj-stallography. As the
latter is an exceedinfjly difficult science, re-
course is generally had to the third method,
upon which some remarks have already been
made in the Ixtroductiox, p. xlii ; the
fourth is indispensable in many cases, but
requires expensive apparatus and great prac-
tice ; the fifth is only partially applicable.

The forms of crystals vary according to
the conditions under which they are pro-
duced; but there can be no doubt that, under
absolutely the same conditions, their forms
woidd be relatively constant. In mauv ani-
mal and other liquids, the forms assumed by
the crystals deposited are tolerably charac-
teristic, so that their composition may be
inferred ; but where accuracy is reqiured, it
is always well to use chemical reagents.
See Raphides.

The cavities in topaz and other mineral
crystals were shown years ago by Brewster
to enclose a liquid, crystals, or even a va-
cuum. This subject has been further in-
vestigated bj' Sorby and Rutley iu rocks,
stones, lava, &c., aud important geolog-ical
conclusions have been deduced therefrom.
Attention has also been drawn to the cavi-
ties containing air or vapour in artificial
crystals, aud to the crystals formed in blow-
pipe beads.

Crystals, when rapidly formed, constitute
beautiful microscopic objects ; the arbores-
cent, radiating and other appearances which
they present are well knowu ; and a more
exquisitely curious and interesting sight
cannot be witnessed than the very formation
itself taking place under the the microscope.
This may he readily seen in a drop of any
saline solution spontaneously evaporating
upon a slide. See Ueic acid and Polar-
ization; and for crystals iu plants, Ra-
phides.

BiBL. Sorby, Geol. Jn. xviii. ; id. (blow-
pipe beads) Mn. Mic. Jn. i. .349 ; and Jn.
Mic. Soc. 1878, i. 1 ; Guy, Mic. Trans.
1868, 1 ; Davies-Matthews, M)M«ijw9, 111 ;
also Chemistry, Crystallography, and
Rocks.

CTENOSTO'MATA.— A suborder of
Infundibulate Polyzoa (Bryozoa). Distin-
guished by the cell-orifice being surrounded
by a fringe of bristles (more or less deve-
loped) when the animal is protruded.
Families :

AlcyonidiidcB. . Polypary spouge-lilve,
fleshy, irregular in shape ; cells immersed,
with a contractile orifice.

Vesiculariidce. Polypary plant-lilce, horny,
tubidar ; cells free, deciduous, the ends
flexible and invertible.

Pedicellinidce. Polypary plant-like, creep-
ing, adherent, sending up at irregular
intervals free, erect, stalked bodies, without
distinct cells.

Flustrellidce. Cells immersed in a gela-
tinous crust, orifice bilabiate.

CUCULLAXUS.

[ 220 ]

CULICID.E.

Arachniidce. Cells more or less distant,
membranous.

JBi(skud(s. Cells contracted below, not
continuous witli the creeping stolon ; with
a ventral apertiu'e.

CyUndracidfe. Cells not contracted below,
closely united to the stem ; no membranous
area.

TritkellidcB. Cells horny, with an aper-
ture, and a ventral membranous area ;
attached to a rigid peduncle by a moveable
joint, deciduous.

VictoreUidce. Cells originating in an en-
largement of the creeping tubular stem,
with which they are continuous at the base ;
free and cylindrical above, not deciduous.

BiBL. Johnston, Br, Zooph. ; Gosse,
Mar. Zool. ii. ; Hincks, Polyz. 489.

CUCULLA'NUS,MU11.— Agenus of Eu-
tozoa, belonging to the order Coelelmintha,
and family Nematoidea.

Char. Body elongate, posteriorly attenu-
ate ; head broad, with a bivalve manduca-
tory apparatus ; mouth anterior, terminal,
forming a long vertical fissure.

C. eleijans. In the intestine, stomach,
and pyloric appendages of the perch and
other 'freshwater fishes. Almost all the
other species of this genus live in the in-
testines of fishes. Length 1-6 to l-o".
Colour, reddish yellow.

C. foveolatm, in the plaice.

BiBL. Dujardin, Helminthes, 245 ; Cob-
bold, Paras. 474.

CUCURBITA'RIA, Grev. See Sph^-

KIA.

CU'LEX, Linn. — A genus of Dipterous
Insects, of the family Culicidje.

CJuir. Palpi longer than the proboscis in
the male, very short in the female

Manv species. C. ^npiens, the common
gnat. "^See CvLiciJi^

CULTC'ID^.— A family of Dipterous
Insects, as the type of which the common
gnat ( Cule.v pipiens) may be examined. _

The parts of the mouth are produced into
a slender elongated rostrum or proboscis,
which is nearly half the entire length of the
insect, and slightly thickened at the tip.
This proboscis,"sim"ple as it appears, in re-
ality consists of seven pieces in the females,
besides a pair of many-jointed palpi, which
are as long as, or even longer than, tlie
rostrum in some of the males, and very
hairy at the extremity; in the females, how-
ever, they are generally very short. Head
email. Anteuna3 slender and filiform, as
long as, or longer than the thorax, and 14-

jointed in both sexes, but plumose in the
male (PI. .33. fig. 21) and pilose in the
females (PI. .3.3. tig. 30 «) ; the basal joint
is subglobose and tubercular in form. Eyes
lunate ; ocelli obsolete. Thorax oblong-
oval. Abdomen long and slender, upon
which the wings are incumbent when at
rest ; the latter have the veins fiu-nished
with scales (PI. 34. fig. 22). Legs very
long and slender.

The proboscis of the female is composed
of the following parts : — 1. An outer tubular
canal (PI. 33. figs. .30 & 31 e), representing
the labrum, forming the most robust part of
the mouth, except the labium. 2. A pan- of
slender, needle-like pieces, the mandibles,
serrated on the inside near the tip (PI. 33.
figs. 30 & 31 /), thickened at the back, like
a scythe, and transversely striated. 3. A
second pair of very delicate and slender
organs (PI. 33. figs! 30 & 31 r/), dilated at
the base, to which the palpi are attached,
representing the maxillae. 4. A slender,
needle-like instrument, lanceolate at the
end, traversed by a narrow canal (PI. 33.
figs. -30 & 31 d), the analogue of the tongue.
5. The outer tubular canal ( PI. 33. fig. .30 /),
in which the others are lodged when at
rest, and representing the labium. The
labrum and labium are each traversed bv a
longitudinal slit throughout their length".

It appears that in the males the labrum
and tongue are absent. It has been sup-
posed that, when the lancets of the female
gnat are introduced into the skin, a veno-
mous liquid is simultaneously instilled into
the woimd, and that the great irritation
produced may thus be accounted for. It is
more probable, however, that this arises
from the deeper penetration of the lancets
into the skin ; for they are of great compa-
rative length — about four times that of the
lancets of the flea.

The eggs are deposited in a small boat-
shaped mass which floats upon the surface
of the water. They are oval, with a small
narrow knot at the top, and are arranged
side by side, and closely packed.

The lar^ fe inhabit standing waters, and
may be observed frequently, during the
spring and summer, jerking themselves
about with great agility, or suspending
themselves, for the purpose of respiration,
immediately below the surface of the water,
with the head downwards; Tiie head (PI.
35. fig. 1) is distinct, large, rounded, and
furnished with two unjointed antenna, and
several ciliated appendages, which serve for

CULTIVATION.

[ 221 ]

CURCUMA.

obtaining- nonrisliment. The thorax is fur-
nished with bundles of feathery hairs ; the
abdomen is long, nearly cylindrical, much
narrower than the front parts of the body,
and divided into ten segments, the eighth
of which is furnished with a long respiratory
air-tube, terminated by a small star ; the
last joint is terminated by setae, and by live
conical slender plates.

After several moultings, the larvse are
transformed into pupae, w^hich also move
about with agility by means of the tail and
two terminal swimming organs. In this
state they take no food ; and the position in
which they suspend themselves in the water
is the reverse of that previously assumed,
?. e. the head is upwards. The respiratory
organs consist of two air-tubes placed upon
the thorax ; and the body is much curved.
The final transformation takes place in three
or four weeks, the exuvife of the pupa serv-
in"- as a raft, upon which the insect remains
until its wings are extended.

BiBL. "SYestwood, Introcl. 507 ; Robineau
Desvoidy, Mem. Soc. d'Hist. N. iii. 1827,
390 ; Stephens, Zool. Jn. i. ; Curtis, Brit.
Entom. xii. 537; Macquardt, Dipt. (Suites
a Bi(f.);y<'iillieY, Insect. Brit^ Dipt. iii. 242.

CULTIVATION or CULTURE.— This
term has recently been iised in a specific
sense, to signify the growth of the Schizo-
mycetes, such as Bacterium, Bacillus, &c.,
inartificial liquids. It has been observed,
that when these organisms reproduce them-
selves in organized bodies, the reproduction
takes place" by simple vegetative division.
But when grown in the artificial soils, wdth
free exposure to air, they produce new forms
and give rise to spores. At the same time,
in the case of those Bacteria &c. which are
the origin of specific diseases, their viru-
lence is found to be destroyed ; and on in-
oculation, instead of the original virulent
disease being produced, a mUd form of the
same, which exerts a protective iniiuence,
is the residt.

Several cultivation-liquids have been
used, among which the following may be
mentioned. Pasteur's liquid, composed of
phosphate of potash 2 pts., phosphate of
lime "2, sulphate of magnesia -2, tartrate of
ammonia 10, sugar-candy 150, and water
857 pts. ; or tartrate of ammonia 1 pt.,
yeast-ash 1, distilled water 100 pts. Cohu's
liquid consists of 1 pt. phosphate of potash,
1 sulphate of magnesia, 2 tartrate of am-
monia, and "1 of chloride of calcium m 200
pts. of distilled water. These liquids should

be thoroughly sterilized by boiling before
use, and should be kept in stoppered
bottles. More recently, the cut surface of
a potato, or beetroot, has been used as a
cultivation-bed ; also a layer of gelatine so
saturated with water as just to solidify on
cooling. In these experiments, it has been
found that there is no transition of forms,
at least among the pathogenous Schizomy-
cetes ; a micrococcus producing micrococci, a
bacillus bacilli, and a spirillium sjnrillia
only.

BiBL. See ScHizoMYCETES ; Maddox,
M. M. Jn. 1870, iii. 14 ; Koch, Qu. Mic.
Jn. xvii. 87, and xxi. 050 ; Lister, ibid, xviii.
191 ; Klebs, Rep. Intern. Med. Cong.,
Times, Aug. 8, 1881 ; Pasteur, ibid. Aug.
9, 1881.

CUNEOLINA, D'Orb.— A Textularian
Foraminifer, extremely compressed trans-
versely to the usual direction of the com-
pression in Textularia.

Rare in the Lower Cretaceous forma-
tion.

BiBL. D'Orbigny, For. Foss. Tien. 1846;
Carpenter, Infrod. For. 193.

C UPRESSIN'E.E.— A suborder of Coni-
ferae (Gymnospermous Flowering Plants),
distinguished from the Abietinefe by the
erect ovules and spheroidal pollen-grains.
Further particulars will be found under
Conifer.^ and Wood.

CURCU'LIO, Linn.— A genus of Coleo-
pterous Insects of the family Curculionidae
(weevils).

Curculio imperialis, the diamond-beetle,
is well known on account of the splendid
colours which its elytra exhibit. Many
other members of this family present co-
loiu-s almost equally brilliant. These colours
are produced mainly by the action of minute
scales upon the incident light. See Scales
OF Insects.

The oral organs of the Curculionidse are
curiously placed at the end of an elongated
rostrum which represents the head, and
to the sides of which the antennae are at-
tached.

BiBL. Westwood, Introd. ; Stephens,
British Beetles.

CURCU'MA, L. — A genus of Zingibera-
cese (Monocotyledons), remarkable on ac-
count of the tuberous rhizomes. Those of
C. lomja form the substance called turmeric;
and the starch from the cells of the young
tubers forms one of the kinds of East- Indian
arrowroot. The tubers of other species
yield very pure starch, and furnish East-

CUSCUTA.

[ 222 ]

CYATHE^.

Indian arrowi-oots. The grains of an un-
known Curcuma imported under that name
are represented in fia-. 19 of Plate 46.
. CUS'CUTA, Touruefort.— A curious ge-
nus of Convolvulaeeae (Dicotyledons), con-
sisting of parasitical, leafless plants, annual
or perennial, nourished by short radical
processes, which they usually send into the
interior of the stems of the plants upon
which they live, although they sometimes
afHx themselves to leaves also ( C. Epithy-
mtim). C. Epi/hmm, wdiich grows in cul-
tivated fields of flax, and C. TrifuUi, para-
sitical on clover, twine round the stems Uke
a fine red string, and produce root-pro-
cesses in rows on the side next the nurse-
plant, never on the free side. Careful
sections show that the woody structm'e of
the roots of the parasite penetrates the cam-
hium (or even the pith) of the nurse-plant,
and becomes completely grafted on it. In
the perennial kinds {C. verrucosa), the roots
become imbedded in the annual rings. The
embryo of Cuscnta is curious, being filiform,
and coiled up like a watch-spring in the seed.

BiBL. Wheeler, Phytolocjist, i. 753;
Brandt, Linncea^ xxii. 81 ; Schacht, Beit,
z. An. nnd Phys. 1854, 167 ; Uloth, Flora,
1860, 265.

CUSPIDEL'LA, Hincks.— A genus of
Hydroid Polj'pi ; family Lafoeidse.

C. Jmmilis. Wales, Shetland, Northum-
berland.

BiBL. Hincks, Brit. Zooph. 209.

CUTICLE or Animals. See Skin.

CUTICLE OF Plants. See Epider-
mis.

CUTLE'RIA.— A
genus of Cutleriacea3
(Fucoid Algae), re-
presented in Britain
by C. multi/ida, -which
has a " rooting," fan-
shaped, irregularly
laciniated frond from
2 to 8" long, the laci-
nise riband-like, be-
tween cartilaginous
and membranous,
olive, with scattered
sori, Ijearing on some
pl:ints(which have an
orange tint) antheri-
dia, and on others oo-
sporatif/es (fig. 148).

The oosporanges
(fig. 148) occur at
the bases of tufted

Fig. 148.

hairs, and are oblong stalked bodies, divided
by perpendicular and transverse septa into
(usually) 8 chambers, each of which gives
birth to a zoospore capable of germination.
The antheridia occur in an analogous con-
dition on distinct plants ; they are more
sausage-shaped, and divided into a greater
number of minute chambers, from which
the spermatozoids or antherozoids are ex-
pelled when mature ; these have never been
seen to germinate.

BiBL. Ilarvev, Mar. Alg. 36, pi. 6. A ;
Phyc. Brit. pL 75; Greville, Brit. Alg.
pl.'lO; Thuret, Ann. Sc. Nat. 3 ser. xiv.
241, pi. 31, xvi. 12, pi. 1; Kutzing, Phijc.
gen. pi. 25. fig. 2.

Fig. 149,

Cutleria dichotoma.

Fragment of a frond.

Kat. size.

Cutleria dichotoma.
Section of a lacinia of a frond, showing the etalked
eight-thambered oosporanges growing in tufts with
intercalated hairs. Magnified 50 diameters.

CUTLERIA 'CEyE.— A family of Fucoid
Algfe. See Cutleria.

CUTTLE-FISH. See Sepia.

CYATHEVE.— A family of Polypodia-
ceous Ferns, distinguished by the dorsal
globose sori, often at or near the forking of
a vein, and the insertion of the sporanges
on a projecting axis, the annulus of the
sporanges being vertical' (fig. 151) ; indu-
sium (except in Aho^^JdJa) enclosing the
sori.

CYATHEA.

[ 223 ]

OrCLAMMINA.

Tropical or subtropical, mostly arbo-
rescent.

Genera.

Cyathea. Sori hemispherical, regularly
aiTanged. Indusium at first closed, at
length bursting in a circumscissile manner,
and cup-shaped.

Ahophila. Sori globose, regularly ar-
ranged. Sporanges inserted on a globose
axis, and imbricated.

Ilcmiti'Ua. Sori globose, each solitary
on a venule. Indusium an ovate, concave,
torn scale, situated at the lower side of the
base.

Cnemidaria.

Dicalpe. Receptacle small, scarcely ele-
vated. Indusium liard-membranaceous, en-
tire, finaUy bursting irregularly at the
summit ; capsules numerous, nearly sessile,
annulus broad.

Mutonia. Keceptacle expanded into a firm
and membranaceous umbrella-shaped ob-
scurely 6-lobed indusium, enclosing 6 large
sessile capsules.

Thyrsopteris.

CYA'THEA, Smith.— A genus of Cya-
the88(Polypodiaceous Ferns), most of which
are tropical. They have a cup-like in-
dusium, whence the name. Arborescent.
(Figs. loO, 151.) 55 species.

Fig. loO.

Fig. 151.

Cyathea elegans.
Fig. 150. Pinnule with sori. MagniBed 5 diameters.
Fig. 151. Vertical section of a sorus in a cup-like in-
dusium. Magnified 25 diameters.

BiBL. Hooker and Baker, Syn. Fil. 16.

CYATHO'MONAS, From. = Monas
truncate or excavate in front.

8 species ; freshwater ; length 1-3000 to
1-1000". C. spissa (PL 53. fig. 17).

BiBL. Fromentel, Microzoaires ; Kent,
Inftis. 141.

CY ATHUS, Hall.— See Xidulariacei.

CYCADA'CE.E.— A family of Gymno-

spermous Flowering Plants. The micro-
scopic structure of the wood is analogous to
that of the Conifers; and the mode of ferti-
lization of the ovules is similar. (See Gym-
NOSPKRMi.A..) Species of Cycas, Zar/iia, &c.
are commonly cultivated in botanical gar-
dens. Tliey offer interesting subjects of
microscopic investigation. The parenchy-
matous tissue, in the form of pith, large
medullary rays, and in Cycas of concentric
rings alternating with those of the wood, is
remarkable for the quantity of starch con-
tained in it at certain periods. Tliis is ex-
tracted and used as arrowroot or sago. Cycas
circinalis furnishes a kind of sago (its starch-
grains are represented in PL 46. fig. 17).
Dion edule yields a kind of arrowroot in
Mexico. Encephalartos yields Caffre-bread
at the Cape, &c. The wood is composed,
in Cycas and Zamia, almost wholly of large
dotted tubes, somewhat hke those of Arau-
caria (with many rows of bordered pits)
(PL 48. fig. 20) ; but a medullary sheath
exists, composed of unrollable spiral vessels,
with tubes of varied character, reticulate,
annular or other fibrous forms, as in the
Dicotyledons ; and in Zamia the dotted
tubes are said to be uuroUable in some cases
into spiral ribands. In Zamia and Ence-
phalartos there does not appear to be a dis-
tinction of concentric rings of wood ; but
in Cycas these exist, separated by layers of
cellular tissue. The rings, hoAvever, are
not " annual," only five or six existing in
large old trunks. The leaves of the Cyca-
dacese possess a remarkably solid epidermal
structure ; and in Cycas the upper thickened
walls of the epidermal ceUs exhibit pore-
canals or deep pits running from the cavity
of the cell towards the outer sm-face, as well
as towards the contiguous cells (PL 47.
fig. 28). See Epidermis. The pollen of
the Cycadaceae is angular, collected in
masses, and transparent ; it is contained in
anthers of peculiar form seated on the lower
surface of the scales of the male cones.

BiBL. Don, Ann. Is. H. v. 48; Linn.
Trans, xvii. ; Brongniart, Ann. Sc. Nat.
xvi. 589 ; Mohl, Verm. Schrift. 195 ; Link,
Icon. Select, fasc. ii. t. ix. & xv. ; Miquel,
Linncea, xviii. 125, and pis. 4, 5, 6 {Ann.
Sc. Nat. 3 ser. v. 11). Also the Bibl. of
Gymno.spermia.
CY'CAS, L. See Cycadace.e.
CYCLAM;MINA, Brady.— An arena-
ceous Foraminifer ; nautiloid, subglobose,
with numerous chambers, lab\Tinthic with-
in ; last chamber opening with a transverse

CYCLIDINA.

[ 224 ]

CYCLOPS.

slit and some large pores. Recent ; in deep
parts of tlie Atlantic and Pacific.

BiBL. II. B. Brady, Qu. Mic. Jn. xis.
p. 43.

CYCLIDI'NA, Ehr.— A family of In-
fusoria.

Char. No carapace; a single alimentary
orifice ; appendages in the form of cilia or
bristles.

{Flattened, cilia form-
inp; a circle Cyclidium.
Bounded, cilia scat-
tered Panfotrichum.

bristles Chcetomoiias.

BiBL. Ehr. Infus. p. 244.

CYCLIDIUM, Hill, Ehr.— A genus of
Holotrichous Infusoria.

Char. Body compressed ; organs of loco-
motion a circle of abdominal cilia-like feet ;
mouth ventral, -o'ith a hood-shaped exten-
sile membrane.

C. f/laucoma (PI. 30. fig. 37 c, side view ;
d, dorsal view). Oblong-elliptical, entire,
-with a long saltatory seta in front (behind,
Kent); circle of cilia large; dorsal lines
very fine ; contractile vesicle placed at the
front end (back, Kent) ; freshwater ; length
1-2880 to 1-1150". CI. & L. include under
this species Acomia ovuhim, Ah/scum saltans,
Enchelys iriquefra, and Uronema marina.

C. viaryaritaceum. Orbicular-elliptic,
slightly emarginate posteriorly ; cilia obso-
lete ; pearly; freshwater; length 1-2100 to
1-1000" (this is Glaucoma inaryaritaceiim,
Clap. & Lachm.).

Two doubtful species, — C. ^ilarmm and
lentiforme.

C. el(»if;atiim, CI. & L.

Dujarciin includes his species of CycU-
dium, the relation of which to those of
Ehrenberg is doubtful, in the family Mona-
dina, with the characters —

Bodv disk-shaped, depressed or lamelli-
form, but httle variable in form, with a
single flagelliform filament. Four species ;
freshwater.

C nudtdosum. "With series of nodules
and vacuoles; motion extremely slow;
length 1-530".

C. abscissttm (PI. 30. fig. 37 b). Lamcl-
liform, oval, truncated posteriorly ; motion
slow: length 1-020".

C. distortum (PI. 30. fig. 37 a). Oval,
nodular, irregidarlv twisted ; margin thick-
ened ; length 1-1800".

C. crassnm. Length 1-1800 to 1-1100".

BiBL. Ehr. Infus. 245 ; Duj. Infus. 28G;
CI. & L. Inf. 27i ; Kent, Inf. 544.

C YCLOCH.E'TA, Jackson.— A genus of
Peritrichoiis Infusoria, allied to Trichodina.
C. sponf/iUce. In the interstices of the
freshwater sponge.

BiBL. Jackson, Qu. Mic.Jn. 1875 ; Kent,
Inf. 050.

"CYCLOCLY'PEUS, Carpenter.- A re-
latively large, discoidal, Nummuline Fora-
minifer, winch grows by concentric annuli
of chamberlets, instead of spirally with suc-
cessive chambers. It thus beai-s the same
relation to its ally Hcteroste(/ina that Orhi-
tolites does to Orbiculina. Known only re-
cent from Borneo.

BiBL. Carpenter, Phil. Tr. 1856 ; Foram.
292.

CYCLOGLE'NA, Ehr.— A genus of Ro-
tatoria, of the family Hydatintea.

Char. Eyes more than three, forming a
cervical group ; foot forked.

Pharyngeal jaws with one or perhaps
three teeth.

a lupus (PI. 43. fig. 18). Body ovate-
oblong or conical, not auricled; foot and
toes short ; aquatic ; length 1-144 to 1-120".
C. ? clef/ans. In Egypt.
BiBL. Ehr. Infus. p'. 453.
CYCLOGRAM'MA, Perty.— A genus of
Infusoria.

C. rtdjcns = a Kassula, CI. >t L.
BiBL. Clap. & Lachm. Infus. p. 326 ;
Pertv, Lebensf. p. 146.

CYCLOLiNA, D'Orb.— An excessively
thin di,■^coidal condition of Patellina, con-
sisting of perfect annidi and very little um-
bilical cell-growth. In Cretaceous strata,
France.

BiBL. D'Orb. For.Fos. Vien. 139; Par-
ker and Jones, Ann. N. II. ser. 3, vi. 30;
Carpenter, Introd. For. 230, 233 ; Carter,
An. N. H. 1861, Dec, 464.

CYCLOPI'NA, Clans.- A genus of Co-
pepodous Entomostraca.

C. littoral is, gracilis, and ovalis ; in dredg-
ings.

BiBL. Brady, Copep. i. 91.
CY'CLOPS, Miiller.— A genus of Cope-
podous Entomostraca, family Cyclopida?.

Char. Foot-jaws large and strong,
branched ; eye single, frontal ; inferior an-
tenna) simple ; external ovaries two. (Both
superior antennae in the male furnished with
the swelling and hinge-joint.)

a qjiadricornis (Pi. 20. figs. 8-15). The
only species. Variable in . colour ; fresli-
water ; length 1-17 to 1-14".

Thorax composed of four, and abdomen
(apparently the tail) of six segments ; head

UYCLOrS.

[ 225 ]

(JYCLOTELLA.

Cdiisolidated with the first and largest joint
of the thorax ; last joint of abdomen con-
sisting' of two separate lobes.

Superior antenna3 (hgs. 8, 9 a) composed
of many joints (twenty-six, Jiaird), from
each of which one or more setfe arise ; in
tlie male, each superior antenna exliibits a
swelliuii- at about its middle (tig. 8 b), fol-
lowed by a sudden contraction, the first
articulation of which forms a hinge-joint ;
inferior antenuaj (tig. 9 b) four-jointed, each
joint with seta^, the terminal with six of
unequal length. The mandibles (fig. 11)
consist of an ovate body (a), narrowed and
twisted above, and terminating in a number
of brownish teeth, with a marginal serrated
seta (b) ; each mandible has also a palpus,
consisting of one segment and two long-
filaments.

Behind the mandibles, the first pair of
foot-jaws (fig. 12) are situated ; each con-
sists of a body, convex externally, concave
internally, furnished at the end with two or
three strong teeth, and with a single-jointed
palp-like organ terminated by setse.

The second pair of foot-jaws (fig. 13 a b)
are divided to the base into two portions ;
an internal (b) smaller, and consisting of
four joints, each with one or more setigerous
spines, the last with three ; and an external
(a) composed of three joints, to the base of
the first of which the internal portion is
attached ; this first joint is the longest, and
furnished on its inner side with two tuber-
cles, each with one or two setigerous spines,
a longer jointed spine arising from near its
distal extremity ; the second joint is fm'-
nished with two strong claws of nearly equal
size ; and to its upper edge is attached the
third joint, smaller than the second, also
furnished with two claws; some of the
spines are themselves setigerous.

There are five paii'S of legs or feet, four of
which are branchial, uniform, and arise from
the thoracic segments. Each of these legs
(fig. 14) is composed of two branches arising
from a common base ; each branch is three-
jointed, and each joint is furnished with
elegantly plumose setae, the last having six
or seven. The fifth pair of legs (fig. 15) are
rudimentary, and arise from the first and
smallest segment of the abdomen ; they are
two-jointed in the female, and three-jointed
in the male.

The external ovary (fig. 9) communi-
cates directly with the internal by means
of a small canal on each side between the
first and second segments of the abdomen.

The tail consists of two lobes, each termi-
nated by four variously setigerous filaments,
the two intermediate being the longest, and
jointed near their origin ; sometimes there
are two Joints to each, and the outer ones
are also jointed.

Scarcely a pool of water can be found in
which this animal may not be seen darting
about in various directions. It varies greatly
in structure and appearance, according to
age, locality, sex, &:c. ; and these varieties
have been admitted as so many species by
some authors.

n. 20. fig. 16 represents a recently hatched
Cyclops (Nanplius-ioYm) .

The individuals are frequently covered
with VorticeUceanA other parasitic Infusoria.
BiBii. Baird, Ent. 198 ; Koch, Deutschl,
Crustac; Clans, Wier/. Arch. 1857 ; Tr.M.
Soc. 1880, 251; Brady, Copep. {Ray Soc).
CYCLO'SIS. See Rotation.
CYCLOSTO'MATA.— A suborder of
marine Infundibulate Polyzoa.

Families : Tubuliporidje, Crisiidfe, Hor-
neridffi, and Lichenoporidae.

CYCLOTEL'LA, Kiitz.— A genus of
Diatomaceae.

Char. Frustules free or adherent, disk-
shaped, mostly solitary; valves circular,
flat, convex, depressed or undulated, stria-
ted ; strife radiating.

The frustules of some of the species are
immersed in an amorphous gelatinous sub-
stance.

When the valves of (all ?) the species
of Cydotella are examined under an object-
glass of large aperture, Avith the central
stop (Inte. p. xix), the surface is found to
be marked with dots in radiating rows, as
in some species of Coscinodiscus ; hence
these two genera should probably be united.
Some appear to represent the fiaistules of
Melosira seen in end view.

C. oncrcuJata, K. (Pyxkh'cula opercniata,
E., Discopka Knfzmyn^E.) (PI. 16. fig. 21 ;
a, side view ; b, front view). Angles of
frustules in front view rounded ; stri89 ob-
scure, very short, giving the margin a punc-
tate appearance ; freshwater ; diameter
attaining 1-1000".

/3. rectangnia, K. (C Ki'dzhigiana, S.)
(PI. 10. fig. 22). Angles of front view not
rounded ; striae more distinct.

. C.Menef/hiniana. Valves plane, distinctly
striated at the margin ; fr. wat. ; length
1-1440".

^. major. Twice as broad.
C. antiqwt, S. (Discopka atmosphenca,

Q

CYCLOTEIOHA.

[ 226 ]

CYLINDROTHECA.

E.). Valves convex ; striae broad, reaching
neither the centre nor the margin : fr. wat. ;
diam. 1-7G0".

Kiitziug characterizes three marine spe-
cies, Avith the valves free from striae, and
seventeen doubtful species, marine and fos-
sil, belonging to the genera Actinocydus,
Discoplea, and Hyalodiscus of Ehreuberg.
Rabenhorst describes 9 species,

BiBL. Kiitzing, Syn. Dial. Bacill. 50, and
Sj). Aly. 18; Ehrenberg, Bcrl. Ber., Infus.,
and Mikrog. ; Smith, Brit. Diat. 27 ;
Thwaites, Ann. N. H. 1848, i. 169.

CYCLOT'RICHA, Kent.— A genus of
Holotrichous Infusoria.

C citrea=Ophryoylena citreum, 01. &
Lachm.

CY'CLOUM, Hass.— A genus of Infun-
dibulate Ctenostomatous Polyzoa.

Char. Zoar}' fleshy, iucrusting, covered
with imperforate papillfe ; ova in clusters.

C. impUlosum. Tentacles 18 ; on Fucus
serrafns : referred to Alcyonidium.

BiBL. Hassall, Aym. N. H. 1841, vii.
p. 483; Gosse, Mar. Zool. ii. 19 (fig.);
Hincks, Polyz. 493.

CYLINDROCYS'TIS. See Cocco-

CHLOHIS.

CYLINDRCE'CID^. — A family of
Ctenostomatous Polyzoa.

Gen. : Cylindroccbim and Anyuixella.

CYLINt)R(E'CIUM, Hincks.— A genus
of Cyhudrrecidee, Ctenostomatous Polyzoa.

Cliar. Cells elongate, cylindrical, arising
from a creeping stolon; no gizzard. 3
species, marine, on rocks, sea-weeds, &c.

BiBL. Hincks, Polyz. 535.

CYLTNDROLEBE'RIS, Brady.— A ge-
nus of Ostracode Entomostraca, fam. Cypri-
dinidee.

2 recent British species : C. marue and
C teresj both marine.

BiBL. Brady, Linn. Trans, xxvi. p. 404.

CYLINDR'OPSYL'LUS, Brady.— A ge-
nus of Copepodous Entomostraca. C. Icevis,
in dredgiugs.

BiBL. Bradv, Copcp. (Bay Soc), iii. 30.

CYLINDRbSPER'MUxAI,Klitzing(^r2rt-
buina, Bory and others). — A genus of
Nostochaceae (Confervoid Algae), with the
filaments less radiating than in the allied
Sphccrozyya ; distinguished under the mi-
croscope by the resemblance of the filaments
to an aunulose animal ; the ordinary cells
looking like a long jointed body, the large
elliptic sporangial cell like a thorax, and the
terminal ve.:^icular cell often bearing fine
hairs, like a head. British species :

C. catenatum, Ralfs (PI. 8. fig. 4). Fila-
ments monilif orm ; ordinary cells orbicular ;
vesicular cells oval ; sporanges oval, cate-
nate. (Ralfs, Ann. N. H. 1850, vol. v. pi. 9.
fig. 14.) Forming a bluish stratum, con-
taining very delicate, elongated, straight or
slightly flexuose, generally parallel filaments.

The remaining British species are not de-
scribed by Ralfs ; but the following are
noticed as British by Kiitzing.

O. macrospermiim, Kiitz. Filaments
thick, equal ; ordinary cells oblong, l-700th
of a line in diameter ; sporanges oblong,
tm-gid, fh-m, fuscous, 1-100 to 1-00" ' long,
1-300 to 1-200'" thick. Kiitzing, Sp. Aly.
293 ; Tah. Phyc. vol. i. pi. 98. fig. 4. Ana-
haina impalpehralis, Hassall, Alyce, pi. 75.
fig. 3. Standing water; forming an aeru-
ginous green stratum.

C. mesohptum, Kiitzing. Filaments
densely entangled, unequal, 1-800 to 1-850'"
thick; sporanges oblong, 1-180 to 1-150'"
long, 1-350 to 1-300"' broad, slightly con-
stricted in the middle. Kiitzing, Sp. Aly. ;
Tah. Phyc. vol. i. pi. 98. fig. 5. Anahaina
constricta, Hassall, Algce, pi. 75. fig. 9.
^riiginous green ; in brackish marshes.

Excluded species of Kiitzing : — C. elon-
yatum = Spha'rQzyya eJastica, Ag. (Ralfs);
C. leptospermum = Sphcerozyya leptosperma
(Ralfs) ; C. Car michaelii= Sphccrozyya Car-
michaclii (Harvey) ; C. Balfsii= IJoIicho-
spiermiua Balfsii (Ralfs) ; C. HassaUii= Co-
niophytum Thompsoni (Hassall).

Rabenhorst describes 13 European species.

BiBL, Ralfs on Nostochinece , Ann. N, H.
1850, vol. V. 321 ; Kiitzing, Sp. Aly. ; Ra-
benhorst, Fl. Ah/, ii. 180.

CYLINDROS'PORUiAI, Grev.— A sup-
posed genus of parasitic Fungi, stated by
Tidasne to consist of the conidiiferous forms
of Sphaeriacei.

C. concentricum, Grev. = Uredo cylindro-
spora ,\\oo\<.. Br. FL, grows upon the leaves
of cabbages. It appears however, that
Greville's plant is really a species of Glao-
sporinm, and quite different from the fungi
with Avhich it has been confounded.

BiBL. Grev. <S'c. Crypt. Fl.t. xxix.; Berke-
ley, Mort. Tr. iii. 2Go; Tulasne, Ann. Sc.
Nat. 4 ser. v. 100 ; Berkeley, Oidl. 325.

CYLINDROTHE'OA, Rab.— A genus
of Diatomacoa?.

Char. Frustules fusiform, free, ends acute ;
with 2 (rarely 1 or 3) longitudinal flexuous
costae ; no nodules.

C. Gerstenherycri (PI. 51 . fig. 34). Living
i'ruatules cylindrical, obtusely attenuate at

CYLINDROTIlECimi. [ 227 ]

CYNIPID.E.

ends ; dried frustules fusiform, acuminate ;
leiig-tli 1-90". Conimonin pools and ditches
(Germany).

BiBi,. Kabenliorst, Flor. Ah/, i. p. 145.

CYLINDROTIIE'CIUM, i3r. and Sch.
=Nf,ckera.

BiBL. Wilson, Bri/ol. Brit. p. 3i'G.

CYMATONE'MA, Kiitz. = mididate-
constricted G^O(/onia. (Kabenliorst, Fl.
Ah/, iii. 351.)

CYMATOPLEU'RA, Sm.— A genus of
Diatomacefe. This genus was founded by
Hassall as Sphiiicfoci/s/is, and should be re-
tained (see the laws of nomenclature, in the
Ann. N. H. 1843, ii. 259); but Smith's
excellent Monograph has caused his term to
be generally adopted.

Char. Frustules free, single ; in front
view hnear, with undidate margins ; valves
oblong or elliptical, sometimes constricted
in the middle. Freshwater.

Valves with coarse, transverse or nearly
so, rounded elevations appearing as dark
bands ; an interrupted median line ; coarse
marginal dots, and transverse strite ; but
neither alae nor nodules.

Several British species.

S. solea (PI. 16. hg. 23). Valves linear-
elliptic, narrowed on each side towards the
middle ; transverse strife evident ; extreme
length 1-216". Undidations six ; common.

0. JMucli shorter ; undulations fewer,
ends apicidate.

S. elliptica^ (PI. 16. tig. 24). Valves
broadly elliptic, or elliptic-oblong; striae
obscm'e ; undulations foiu- or five ; length
1-280" ; common.

S. hihernica. Valves broadly elliptic,
acuminate ; midulations three ; length 1-
25'0'.

BiBL. Ilassall, Ahjcd, 436 ; Smith, Br.
Dmf. i. 36 ; Eabenhorst, Fl. Ahj. i. 60.

CYMATOSIRA, Grun.— A genus of
Diatomaceai.

Cliar. Frustules united into bands; un-
dulate in front view ; valves lanceolate,
distinctly punctate ; no median line.

C. Lorenzmna (PI. 51. fig. 35). Valves
broadly lanceolate, very convex ; ends pro-
duced. At the bottom of the Adi'iatic.

BiBL. Rabenhorst, Flor. Ah/, i. p. 124.

CYMBALO 'POR A, Hageiiow.— One of
the Foraminifera Globt'i/erinhla, in which
the spiral is merged in a cj'clical growth at
an early stage, the shell increasing by rings
of sac-like chambers, which open into the
hollow base of the trochoid shell. C. Poeyi
(D'Orb.) (PI. 24. f. 17) is the type.

Cymhalopora is rare in the Upper Chalk,
and some Tertiary strata ; more common in
the tropical seas.

BiBL. Carpenter, Foram. 215.

CYMBEL'LA, Ag.— A genus of Diato-
macete.

Char. Frustules solitary, free ; valves
cymbiform, unsymmetrical, with a subcen-
tral and two terminal nodules, a submedian
longitudinal line, and transverse or slightly
radiating striae. Freshwater and fossil.

Frustules sometimes immersed , in an
amorphous gelatinous mass.

C.Ehrenbergii, K, (PI. 51. fig. 2: a, front
view ; h, side view). Broadly lanceolate,
apices slightly produced, somewhat obtuse ;
striae distinct (resolvable into dots) ; length
1-200". (Fossil in San Fiore deposit.)

Several British species, and more fo-
reign, differing from each other by slight
characters.

Rabenhorst describes 31 European spe-
cies, with numerous varieties.

BiBL. Smith, Brit. Dial. 17; Kiitziug,
Bacill. 79, and Sp. Alg. 57.

CYMBOSIRA, Kiitz.— A genus of Dia-
tomacese.

Char. Frustules resembling those ofAch-
nanthes ; solitary or binate, stipitate, attached
end to end, and thus concatenate. Marine.

C. Agardhii (PI. 19. fig. 18). Frustules
linear, slightly arcuate, finely striated,
rounded at ends ; valves oblong-linear,
slightly dilated in the middle, apices ob-
tusely rounded. Length 1-960 to 1-280".

C. minutula, Grun.

BiBL. Kiitzing, Bacill. 77, and Sp. Alg.
57 ; Grunow, Wien. Verh. 1863.

CYNIP'ID/E, Gall-flies.— A family
of Insects, belonging to the Entomophagous
section of the order Hymenoptera.

Char. Head small, transverse; antennfe
inserted in the middle of the face, of mo-
derate length, slender, not geniculated,
composed of twelve to fifteen j oints ; maxil-
lary palpi of four or five, labial of two or
three joints ; thorax oval, gibbous, with the
mesothorax large, and the scutellum very
prominent ; wings transparent, with few
veins, — the anterior usually with three or
four cells, and the posterior with a single
vein ; abdomen sKort, much compressed,
with a short peduncle, its basal segment veiy
large, the rest small, forming nari-ow rings.

In the females of these insects, which are
all of small and some of minute size, the
last segment of the abdomen, which occupies
a considerable portion of its lower surface,

q2

CYNIPIDJE.

[ 228 ]

CYNIPID^.

forms a channel, in which is lodged the very
delicate ovipositor. This organ, the con-
struction of Avhich has heeu the subject of
some controversy, consists, as pointed out
by Westwood, of the same parts as that
of the ordinary parasitic Hymenoptera
{Iclineinnonidcc, Chalcidid(P, Sec), immely, of
a superior bristle, channelled beneath, and
of two finer inferior bristles, which are re-
ceived into the channel of the former.
Although this ovipositor is not exserted, it
is of great length, reaching up to the base
of the abdomen in a subspiral curve ; it is
enclosed at its base between two broad
plates, representing the basal joints of the
bivalvular sbeath of the ovipositor in other
Hymenoptera ; and the slender second j oints
of these valves accompany it to the apex of
the abdomen. All these parts are concealed
within the walls of the abdomen (PI. 36.
fig. 15).

Although placed from their organization
in the same section of the Hymenoptera
as the parasitic Ichueumonidfe, most of
the Cynipidae feed upon \egetable sub-
stances in the larva-state. The females
bore with their ovipositor into the tissues of
plants and trees, and there deposit their
eggs, from which small footless larvee are
produced. The irritation caused by the
injury thus done to the tissues, gives rise
to a morbid action in the part of the plant
attacked, which is thus incited to grow
out into an excrescence varying in size,
form, and structure according to the specific-
nature of the plant, the part of the plant
upon which, and the parasite by which,
the wound has been inflicted. Thus the
oak, which, of all our native trees, is most
infested by Cynipidas, furnishes nourish-
ment to upwards of a dozen species, which
attack all parts of it, from the leaves and
flower-buds to the root, and each of which
confines its operations to a particular por-
tion of the tree, and gives rise to a pecu-
liar excrescence. These morbid growths
are commonly known as ffalls, and the
insects producing them as GaU-Jlies ; the
family, also, is called GalUcola- by some
authors. The larvae feed in the interior of
the galls ; those of some species are solitary,
whilst of others numerous individuals may
be found in the same gall, according as the
parent insect has deposited one or more
eggs in the same spot. When full-grown,
the larvaj usually undergo their transforma-
tions within the gall ; but in some instances
they eat their way out, bury themselves in

the ground, and there pass to the pupa-state.
The larvae are liable to be attacked by
species of parasitic HjTnenoptera, especially
tlie long-tailed Chalcididje (such as Ccdli-
mome, PI. 36. fig. 14) ; these pierce through
the substance of the gall and deposit their
eggs in or upon the Cynipidous larvae,
which are subsequently devoured by those
hatched from the eggs of the parasite.

The recent elaborate researches of Adler
show that the Cynipidae exhibit the phe-
nomena of parthenogenesis, and that they
are dimorphic. Thus, in some broods,
both sexes are present ; while in others, fe-
males only are produced. The members of
the two broods are quite dissimilar, and
have been regarded as constituting diffe-
rent genera ; the galls they produce are also
difl'erent. These observations serve to solve
the mystery existing some years ago as to
the non- occurrence of males among large
broods of Cynips, He also states that the
reproductive organs in the two kinds of
broods are very similar ; and that tliere is a
rudimentary receptaculum semiuis in the
agamic generations.

The tissues of the galls are sometimes
soft and juicy, sometimes hard and woody ;
in the latter case the woody tissue lies im-
mediately beneath the skin, and within it
is a layer of cellular tissue filled with
starch-grains. These galls are usually
formed on branches or twigs. One of the
most remarkable of them is the Bedeguar
gall of the wild rose, which is produced by
the puncture of Rhodifes liosce (PI. 36. tig.
16) : it is a large gall entirely covered with
compound bristles, like those of the moss-
rose, which give it the appearance of a
ball of moss ; in its interior are numerous
cells, each of which serves as a habitation
for a larva ; and the whole is produced at
the extremity of a shoot of the wild rose,
upon which the female gall-fly deposits
numerous eggs.

The Cherry-gall of the oak-leaf is pro-
duced by Cynips folii (tig. 17), one of the
commonest of our native species ; and an-
other gall-fly, Teras termuudis (fig. 18), by
attacking the young shoots of the oak, gives
origin to the well-known oak-apples. The
leav6s of the oak are also attacked by at
least two so-called species of the genus
Neuroterus, which really consists of the
parthenogenetic brood of Spaf/wf/uster, the
punctures of which give rise to small, flat,
rounded galls, attached to the leaf only by a
small portion of their lower surface, and

CYNIPID^.

[ 229 ]

CYPHELLA.

bearing so close a resemblance to certain
Fuiio-i, that tlioy wore at one time supposed
to bi> parasitic vegetable growths. These
galls, which are commonly known as oak-
spamjh's, may be met with in abundance
during the winter on the fallen leaves in oak
woods : the flies are i)roduced in the spring ;
and the most abundant species in this
coimtry is the Neuroteris longipennis (fig.
19). The root of the oak is attacked by
several kinds, one of which, Biorhizn aptera,
the partheuogenetic form of Teras termi-
nalis, is destitute of wings; another de-
posits its eggs in the male catkins of the
same tree, producing a series of galls re-
sembling a small bunch of currants.

It would be impossible for us here to
enimierate the different kinds of galls pro-
duced by these beautiful little insects even
upon our indigenous plants and trees, the
history of which in many cases is very im-
perfect, whilst we have scarcely any in-
formation with regard to exotic species.
The most important of all is the common
gall-nut, which is produced by the puncture
of the Cynips lincforia upon the shoots of
the Qucrcus infectoria, a species of oak
growing in the Levant. The celebrated
Dead-sea apples are also found upon this
oak ; they ai'e as large as a good-sized apple,
and of a spongy texture internally, con-
taining only a single larva of a species which
has been described by Westwood under
the name of Cynips insana.

All the species of Cynipidce do not, how-
ever, produce galls. The species of Hartig's
genus Syneryus deposit theu" eggs in other
galls, upon the substance of which the
larvae, when hatched, feed parasitically, and
finally devour the original tenant. Besides
these species, which live partly upon vege-
table and partly upon animal food, there are
many others, forming several genera in
Hartig's classification, which live entirely
as parasites upon other insects, especially
Aphides and the larvae of Dipterous flies ;
thus justifying the otherwise anomalous
position of the Cyoiipidfe, as a phytophagous
family in the Entomophagous group of the
Hymenoptera. Amongst these we need
only mention the species of the genus Allo-
tria, "SVestw. (Xystus, Hartig), of which a
very abundant one is parasitic upon the rose-
Aphis, and those of the genera Anaeharis,
Figites, and Ihalia. The latter, of which one
species only is known in this country, is
remarkable from the structure of its abdo-
men, which is knife-shaped, and has the

segments nearly equal in length ; Ihalia
cidteJlata (PI. .30. fig. 20) is one of the largest
British Cynipidas.

Adler's admirable memoir, in whieh
many of the galls are figured, will allow of
the identification of most, if not all the
British kinds.

BiBL. Reaumur, Me moire s ; Burgsdorf,
Schriften Gesellsch, naturforsch. Freunde,
iv. ; Boyer de Fonscolombe, Ann. !Sc. Nat,
xxvi. ; Westwood, Introd. vol. ii., May,
Nat. Hist. vi. and viii., and in Guerin's Mag.
Zoohgie ; Walker, Ent. Mag. ii. & iii. j
Brandt and Ratzebm-g, Medizin. Zool. ii. ;
Ratzeburg, Forst-Insecten ; Bouche, Natnr-
gesch. d. Insecten ; Hartig in Germar's Zeits,
fiir die Entomol. ; Adler, Zeitsclir. iviss.
Zool. liii. 151 ; Abridg. McLachlan, Entom.
Mn. Mag. 1881, xvii. 258 ; Jn. Mic. Soc. i.
443 ; Ormerod, Man. Inj. Ins., 1881.

OYNODON'TIUM, Br. and Sch.=Di-

CBANTJM.

BiBL. Wilson, Bryol. Brit. 60.

OYNOPHAL'LU'S.— A genus of Phal-
loidei (Gasteromycetous Fungi), distin-
guished from Phallus by having the pileus
imperforate.

C. caiiinus occurs amongst decayed leaves
in Avoods.

BiBL. Sow. t. 330 ; Berk. Outl. p. 298.

CYNTHIA, Sav.— A genus of Tunicate
Mollusca, of the family AsciDiADiE.

The numerous species are from |-2" in
length.

BiBL. That of the family.

CYPHEL'LA, Fries.— A genus of Hy-
menomycetes (Basidiomj^cetous Fungi),

Fig. 152.

Fig. 153.

Cyphella Taxi.

Fig. 152. Entire plant, magnified 10 diameters.
Fig. 153. Horizontal section of the wall of the cup,
showing the basidioSiiores, magnified 250 diameters.

forming somewhat membranous minute
cups, sessile or stalked upon branches of
trees or upon mosses ; bearing basidio-
spores on a layer foTming a kind of lining
to the cup; the spores ultimately sepa-
rating as a powder in the interior.

Some supposed species of Peziza, as P.
villosa and P. albo-violascens, appear to be
species of Cyphella, or rather sporiferous
states of Pezizce,

CYPHIDIUM.

[ 230 ]

CYPRIS.

BiBL. Fries, Syst. Myc. ii. 201 ; L^veille,
Ann. Sc. Kat. 2 ser. xvi. 237.

CYPPIID'IUM, Ehr.— A genus of Infu-
soria, of the family Arcellina.

Char. Carapace urceolate, tuberculated ;
expansion variable, broad, single and entire.
The carapace is combustible, and re-
sembles a small cube, with a short pedicle.
_ C. mircolum (PI. ?>0. fig. 38). Cubical,
gibbous, expansion (fig. 385) layaline ; fr,
wat. ; length 1-570 to 1-432".
BiBL. Ehr. Infus. 135.
CYPHODE'lilA, Schlumb.— A genus of
Rhizopoda, of the family ArceUina.

Char. Carapace membranous, resisting,
ovoid, elongated in front, recurved and con-
stricted in the form of a neck and marked
with oblique rows of projections ; orifice
circular, oblique ; expansions very long,
filiform, very slender at the end, simple or
branched.

Agrees with Diffliujia enchelys, E. {Tri-
nema, Duj.), in the oblique orifice, the
oblique rows of markings, and the nature
of the expansions, but differs from it in
the presence of the anterior neck-like con-
striction.

Probably species of Em/hjpha (CI. & L.).
C. marf/aritacea. Carapace yellowish, ex-
pansions twice its length ; fr. wat. ; length
1-380 to 1-180".

BiBL. Schlnmberger, Ann. des Sc. Nat.
1845, iii. p. 255.

CYPIIONAU'TES, Ehr.— A genus of
Rotatoria, of the family Megalotrochaea.
Char. Eyes absent ; no teeth.
C. compressus (PI. 43. fig. 19, side view ;
fig. 20, view from above). Compressed,
obtusely triangular, truncate in front, sub-
acutely gibbous at the back ; marine : length
1-180"".

BiBL. Ehrenb. Infus. 395.
CYPREL'LA, I)e Koniuck.— A fossil
Ostracod, related to ' Cxipridina ; carapace
annulated by superficial transverse furrows.
Found in the Carboniferous Limestone of
Belgium and the British Islands.

BiBL. De Koninck, Carh. Foss. Belq.
1844, 589 ; Jones, M. Mic. Jn. 1870, pi. (Vl .
f. 10.

CYPRIDEL'LA, De Kon.- A fossil Os-
tracod closely allied to Cypridina. Very
common in the Carbonifei'ous Limestone of
the British Isles and Belgium.

BiBL. De Koninck, Carh. Foss. Behj.
1844, 590 ; Jones, M. Mic. Jn. 1870, pi. 61.
f. 9.

CYPRLDI'NA, M.-Edwards.— A genus

of Ostracode Entomostraca, fam. Cypri-
dinidfe.

Char. Valves oval or oblong, smooth,
notched antero-inferiorly, posterior end
somewhat produced. Superior antennae
seven-jointed; setfe of moderate length;
natatory branch of inferior antennpe nine-
jointed, bearing moderately long setfe; se-
condary branch very small, subulate. Basal
joint of mandibular feet bearing an entire
subconical and densely hairy process ; pe-
nultimate joint much elougated, and beset
on the internal margin with numerous
ringed setre ; last joint very short and al-
most obsolete.

2 European species : C. Norvegica and C.
Messinensis.

Many fossil forms, apparently identical
with Cypridina, occur in the Mountain-
limestone and the Coal-measures of Europe
and the British Isles ; some also in the
Maestricht Chalk.

BiBL. Brady, Zool. Proc. 1871, 289;
M.-Edwards, Hist. Nat. Crust, jii. 409;
Jones, K., & B., Mongr. Carh. Entom.,
Pal. Soc. 1871.

CYPllID'IUM.— A genus of Hj^otri-
chous Infusoria (Kent, Inf., 215).

C YPRIDOP'SIS,Br.— A genus of Ostra-
code Entomostraca, family Cypridaj.

Char. Those of Cypris, except that the
post-abdominal rami are rudimentary and
setiform.

5 hving British species. C. vidua, Br. =
Cypris vidua, Bd. ; C. villosa, Jir.= Cypris
Westiooodii, Bd.

BiBL. Brady, Linn. Tr. xxvi. 375 ; Ann.
Nat. Hist. 1872, ix. G4.

CY'PRIS, Mliller.— A genus of Ostra-
code Entomostraca, family Cypridae.

Char. LoAver antennfe simple, with a
brush of sette and clawed at the apex ; setae
of upper antennae very long ; feet two pairs,
the last bent up between the valves. Post-
abdominal rami forming two elongate rami,
clawed at the apex. Animal swimming
freely.

Body enclosed within a bivalve, horny,
mostly subreniform uv long oval carapace
or shell. Superior antennfe (PI. 20. fig. 18)
seven-jointed, with pretty long, mostly
feathery filaments, arising from the three or
four last joints. Inferior antennae (fig. 19)
leg -like, five-jointed, giving oft" the tuft of
usually feathery filaments, the last joint
terminated by four strong curved claws.
Labrum composed of a somewhat hood-
shaped piece, projecting between the two

CYRTOSTOMUM.

[ ^'31 ]

CYSTOPHRYS.

inferior antenuaB ; labium or lower lip elon-
o-ated and triang-ular. Mandibles (tig-. 20)
large, pointi'd at one end, with five teeth
at the other, and furnished with a three-
jointed setigerous palp, the basal joint of
which has a small branchial jouit with live
terminal digitations. First pair of jaws
(tig. 21) consisting of a large basal plate (a),
with fonr hnger-like processes at its ante-
rior extremity, one of which is two-jointed,
and all terminated by several long fila-
ments : from the outer edge of this plate
arises a large elongated branchial lamina
(b) giving oft' from its crescentic margin
nineteen long pectinate spines. Second
pair of jaws (ftg. 22) small, and composed
of two flattened joints, the terminal one
having several rigid hairs at the end, and a
lateral palp-like process. First pair of feet
(fig. 23) slender and five-jointed, the last
joint with a strong hook. Second pair of
feet (fig. 24) fom--jointed, the last joint
terminated by two short hooks and a spur-
like posterior filament.

Twenty-seven living British species.

a virens {tristriata, Bd.) (PI. 20. figs.
17-25). Shell oval, and somewhat reni-
form, posteriorly exhibiting three narrow
oblique streaks or dark bands ; valves con-
vex, green, and covered with dense short
hairs. Near the centre of each valve are
about seven small lucid spots. Fr. wat.
very common.

Several fossil Ostracoda are referred to
Ci/pris by palteontologists.

BiBL. Baird, Eidom. 151 ; Straus, Mem.
d. JIus. d. Hist. Nat. vii. 1821 ; Edwards,
Hist. N. Crust, iii. ; Brady, Linn. Tr.
xxvi. 360, and Ann. N. H. 1872, ix. 64 ;
Rup. Jones, Mon. Tert. Entom., Palceont.
Soc. 1836 ; Geol. Mar/, vii. 158.

CYRTOS'TO^IUM, Stein.— A genus of
Holotrichous Infusoria.

C. leucas= Bursaria {Frontonia) I.

CYSTIC OXIDE or CYSTINE.— A
very rare component or constituent of uri-
nary calculi in man and the dog. It is
stated also to occur in the lU'ine, in solution
and as a crystalline deposit ; but we have
never met with it.

Cystine is insoluble in water and alcohol ;
soluble in mineral acids, but not in acetic
acid; also soluble in solutions of fixed
alkalies, their carbonates, and in solution of
ammonia. It is precipitated from its solu-
tion by acetic acid.

Its crystals form colourless, regular six-
sided plates or prisms (PI. 13. group 5) ; the

larger crystals usually exhibit a number of
smaller liexagoual tables irregularly arranged
upon them; sometimes rectangular plates
are met -with. The crystals usually exhibit
but little colour with polarized light. Cys-
tine is most readily obtained in crystals
from a calculus by solution in ammonia and
spontaneous evaporation.

Some of the forms of lithic acid prepared
artificially, resemble those of Cystine (PI. 12.
group 8 b) ; tliey may be distinguished by
the addition of ammonia, which dissolves
the cysthie, but has little or no action upon
the uric acid.

Carbonate of potash also somewhat re-
sembles cystine in the form of its crystals
(PI. 10. fig. 13) ; but water or acetic acid
will at once distinguish them.
_ CYSTICER'CUS, Rud.— Formerly con-
sidered a genus of Cystic Entozoa ; but
now known to be the scolices of Tmnia.
They consist of the short body of a Tcenia,
with the double crown of hooks and the
suckers, terminated posteriorly by a larger
or smaller cyst or vesicle. They occur in
the organs and the tissues of animals ; when
reaching the alimentary canal, becoming
developed into the perfect Tanics. They
have no sexual organs.

C. cdluhsca (PL 21. fig. 3), the most
common, is the scolex of Tcenia solium.
The head is almost tetragonal, neck very
short ; body cylindrical, often longer than
the vesicle ; breadth of cyst half an inch ;
length of body, 1-6 to 2-5", or 1" when ex-
tended. Occurs in the anterior chamber
and beneath the conjunctiva of the Qje,
also in the voluntary muscles and brain of
man ; in the connective tissue of the pig,
producing " measly pork ;" also in the ape,
the dog, the ox, &c. C. tenuicolUs of the
sheep is the scolex of T. marginuta of the
dog ; C fasciolaris, of the rat and mouse
(PI. 21. fig. 3 b, head) = T. crassicollis of the
cat; C. pisifor7nis of the i-nhhlt= T. serrata
of the dog ; C. talpce and C. lonc/icollis, in-
festing moles, become respectively T. tenui-
colUs and T. crassiceps of the fox.

BiBL. Dujardiu, Helm. 632 ; Monier,
Cysticerq. 1880 ; Beueden, Vers Cestoiden ;
Cobbold, Parasites, and the Bibl. of T.^nia.

CYSTINE. See Cystic Oxide.

CYSTOCOC'CUS, Nag. = Pbotococ-
cus.

CYS'TOPHRYS, Archer.— A genus of
Rhizopoda

2 species : C. Hdcheliana and C. oculea,

Bibl. Archer, Qu. Mic. Jn. 1869, 259.

CYSTOPTERIS.

[ 232 ]

CYSTOSEIEA.

CYSTOr'TERIS, Bernbardi.— A genus
of Davalliete (Polypodiaceous Ferns), coii-

Fio-, 154.

Cystopteris fragilis.
A pinnule with the sori covered by the indusia.

Magnified 10 diameters.

tainiug several elegaut little indigenous
species (fig. 154).

BiBL. Hooker and Baker, Syn.Jil. 103.

CYS'TOPUS,Leveille.— A genus of Ure-
dinei (Pliycomycetous Fungi), of which the
' white rust ' common on cabbages and other
Cruciferous plants is a good example ; ap-
pearing in white pustules, eventually burst-
ing and destroying the epidermis of the
leaves, stalks, flowers, and seed-vessels of
the infected plants. When fine slices of
these pustules are examined under the mi-
croscope, the myceHum is found, creeping
among the cells of the parenchyma, com-
posed of inarticulate, tubular, branched
filaments, with a colourless membrane and
whitish granular contents. Numerous rami-
fications spread out in the plane of the
epidermis ; while others spring up in tufts
of two to seven, or rarely singly, perpendi-
cular to tlio former, to produce spores.
These erect branches are at first mere
pouches projecting from the horizontal fila-
ments; they gradually swell into ovate-
cylindrical or club-shaptKl sacs. The con-
tents in the summit of each such sac be-
come organized into a spore, which at leugtli
quite fills up the top of the sac (sporange).
Then the sac or sporange becomes con-
stricted under this first spore, and the for-
mation of a second commences under the
constriction. This is repeated until a neck-
lace-like chain of spores is produced, the
spores subsequently becoming somewhat
cylindrical or cubical. The number apjjears
indefinite ; five and seven spores have been
found in a chain ; they are united by the
constricted portions of the sporange; and

even when they have fallen apart, these
connecting pieces are seen projecting on
them hke parts of a stalk from which thej'
have been broken ofi^. Both the adherent
sporangial membrane and the smooth proper
coat of the spores are colourless, the con-
tents granular and whitish. Tulasue has
recently discovered another form of spore,
spheroidal or trigonal, and of a yellow co-
lour, only one or two of which are foiined
from the end of a fertile filament. Oospores
are also found deeply seated amongst the
mycelium ; and zoospores (PL 27. fig. 14)
have been found by De Bary in C. can-
clidus. See Ueedinei. British species ;
formerly placed in the Uredinei, but more
nearly allied to Peronosporfe : —

C. candklus. Lev. Very common on
Crucifer^e, producing great distortion in the
growth. Uredo Candida, Pers., Grev. Sc.
Cnjpt. Fl. t. 251.

C. cuhicus, Str. On goatsbeard. Cooke,
Exs. no. 88.

C.Sepif/onijDe By. On Spergularia rubra.
Cooke, Exs. no. 88.

Cspinulosus, De By. On Cirstmn arvense.
Cooke, Exs. no. 89.

BiBL. Leveille, A)in. Sc. Nat. 3 ser.
viii. 3G9 ; Berkeley, Jforf. Trans, iii. 265
(figs.) ; De Bary, Brandpilze, Berlin, 1853,
p. 20, pi. 2. figs. 3-7, and Ann. Sc. Nat.
18G3, XX. 130 (zoospores) ; Tulasne, Ann.
Sc. Nat. 4 ser. ii. 108, 171 ; Sachs, Bot.
279.

C YSTOSEI'RA, Ag.— A genus of Fuca-
cea3(rucoidAlg£e),of much-branched habit,
some species of which are common on rocks
in tide-pools or between tide-marks. The
gradually attenuated branches contain in-
fiated air-sacs, atintervalsalongtheir length,
within their substance. The conceptacles
are immersed in the ends of the branches,
which are pierced by their numerous pores.
They contain both spores and antheridia,
but not mixed ; the spores occur at the bot-
tom of the cavity, the antheridia above, near
the pore. The antheridia have only a single
coat. The antherozoids are expelled in a
mass, and soon after begin to move, turning
rapidly upon their axes. They are oval or
spherical in one direction, and rather com-
pressed in the other. They have two cilia
inserted on a red granule; the long cilium
in front moves rapidly, while the posterior
short one is motionless. See Fucace^.

Bibb. Harvey, Mar. Akj. pi. 1 B ; rhyc.
Brif. 133, &c. ; Thuret, Ann. Sc. Nat. 3 s»5r.
xvi. pp. 7 & 10.

CYSTOTRICHA,

[ 233 ]

CYTHERURA.

CYSTOT'RICIIA, Berk, and Jiioome —
A supposed genus of Sphasroneniei (Couio-
mycetous Fungi). Minute fungi forming
dots or lines upon wood from which the
baric has been stripped. Only one species
is described.

C.striohl,^^evk. and Br. Perithecia black,
with a reddish tiuo-e, opening by a reddish
disk.

BiBL. Berk, and Br. Ann. N. H. 1850, v.
467, pi. 1-2. tig. 10.

CYTII'ERE, Miill.— A genus of Euto-
mostraca, of the order Ostracoda,aud family
Oytheridpe.

Char. Shell usually hard, calcareous,
rough and uneven ; mouth with a lip and
labr urn ; masticatory organs well developed ;
maudibles toothed at the end ; lower an-
temi{B four-jointed; upper antennae five-
jointed, last three joints elongated, spini-
ferous ; feet in the male and female alike ;
internal lobe of the first pair of maxillae
weU developed. Not capable of swim-
ming.

Those having the valves almost regidarly
oblong, with the surface very irregular ,being
wrinkled, ridged, and beset with tubercles,
and crenulate or strongly toothed on the
margin, have been separated by Rupert
Jones imder Cythereis.

46 living British species. Many fossil
Cytherae are recorded, which, however,
most probably belong to allied genera, un-
distinguishable by the valves alone. Brady
records 22 species as occurring in post-ter-
tiary deposits of Britain.

BiBL. Baird, Brit. JEnfom. 163 ; Brady,
Linn. I'r. xxvi. 394, and Ann. N. H. ser. 4.
ix. 68 ; Zool. Tr. v. 376.

CYTHERE'IS, Rup. Jones. See Cy-

THERE.

C YTHEREL'LA, R. Jones and Bosquet.
— A genus of Ostracode Entomostraca, fa-
mily Cytherellidse.

Char. Valves unequal, very thick and
calcareous, not notched in front. Upper
antennse very large, seven-jointed, and geni-
culate at the base ; lower broad, flattened,
and two-branched; mandibles very small,
witb a large pectinate-setose palp ; three
pairs of hinder limbs, scarcely pediform, the
two anterior pairs branchial, the others
rudimentary. Abdomen terminating in two
vei-y small, uaiTow, spiniferous lamintc.
Ova and embryos borne beneath the shell
of the female.

2 living British species, C. scofica and C.
Icevis; from deep dredging in tho Minch.

Numerous fossil species, from the Carboni-
ferous to Tertiary strata inclusive.

BiBL. Brady, Linn. Tr. xxvi. 472 ; Zool,
Tr. V. 362 ; R. Jones, Mon. Cret. EnUmi.
1849, 28 ; Mo7i. Tert. Lntom., Palceont. Soc.
1856, 54.

C YTIIERELLI'N A, Jones.— An obscure
fossil Ostracod, very common in the upper
Silurian strata of Britain and Europe.

BiBL. R. Jones, Aim. N. IT. ser. 4. iii.
215.

CYTHERID'EA, Bosquet.— A genus of
Ostracode Entomostraca, family Cytheridse.

Char. Shell subtriangular, thick and com-
pact, smooth, pitted, papillose or rugose.
Mouth with a lip and labrum ; masticatory
organs well developed ; mandibles toothed
at apex; lower antennae four-jointed ; upper
five-jointed, last three joints elongated,
spiniferous ; feet in male and female unlike ;
right foot of first pair in the male prehen-
sile, right of the second pair weak and
rudimentary.

10 living British species. Several fossil
Cretaceous and Tertiary species.

BiBL. Brady, Linn. Tr. xxvi, 421 ; Zool.
Tr. V. 370 ; R. Jones, Mon. Tert. Entom.,
Pal. Soc. 1856, 40, and Geol. Mag. vii. 76,
158.

CYTHERIDETS, Jones.— A subgenus
of Ostracode Entomostraca.

1 living British species, C. subulata ;
some fossil reputed species, Cretaceous and
Tertiary.

BiBL. Jones, Monogr. Tert. Entom., Pa-
IcEontog. Soc. 1856, 46 (shell) ; Brady, A7in.
N. IL 1872, ix. 58 (animal).

CYTHEROPSIS, Sars = Eucythere,
Bradv.

CYTHEROP'TERON, Sars.— A genus
of Ostracode Entomostraca,

Char. Valves of shell unequal, with pro-
minent lateral alee. JNlouth with labium
and labrum ; masticatory organs well deve-
loped ; maudibles toothed ; lower antennae
five-jointed; upper five-jointed; postabdo-
miual lobes broad and short, with three
setae ; eyes none.

9 living British species. Also some Cre-
taceous and Tertiary species.

BiBL. Brady, Linn. I'rans. xxvi. 447,
and Ann. N. II. ,1872, ix. 61 ; R. Jones,
Geol. Maq. vii, 76 and 158,

C YTIIERU'RA, Sars,— A genus of Os-
tracode Entomostraca,

Char. Shell oblong or subtriangular, pos-
terior extremity prolonged into a beak. Su-
perior antennae six-jointed, shortly setose,

CYTISPORA,

[ 234 ]

DACTYLIUM.

tapering- ; inferior anteunte five-jointed ;
terminal claws short ; mandibles robust ;
teeth blunt ; eyes two.

24 living- British species ; also some Cre-
taceous and Tertiary species.

BiBL. Brady, Linii. Tr. xxvi. 439, and
Ann. N. H. 1872, ix. 55 ; R. Jones, Geol.
Mn(i.\n.n, 158.

CYTISTORA, Ehrenb.— A genus of
Sphieronemei (Coniomycetous Fungi), re-
markable for emitting the minute bodies
formerly regarded as spores, agglutinated
together into a more or less gelatinous mass,
in the form of a tendril. The relationship
between the forms called Ci/stispora and va-
rious species of Sphceria has long been no-
ticed ; and Fries stated that he had seen C.
leucostoma pass into S. leiicostoina. C.fiu/ax
was stated by BerL'eley to be exactly ana-
logous to 'S". sdlicina. Recent researches
seem to prove that the present genus, with
Septoria and others, are really only forms
belonging to various Ascomycetous Fungi,
and that they bear the same relationship to
the latter as the spermogonia of Lichens
do to the theciferous fructification. Hence
the so-called spores of Cytispora &c. ap-
pear in reality to be the spermatia or stylo-
sjwres of the Sphajriacei. As these ques-
tions are not yet completely worked out,
we retain the names of these pseudo-genera
and species at present. See SpHJEnrACEi.

Cythpora rubesccns, Fr. Disk dirty brown;
spores {?) reddish. On Rosacefe.

C. chn/sospenna, Pers. Disk black ;
spores yellow. On Poplar bark.

C. carpliosjierma, Pers. Disk dingy;
spores straw-coloured. On Hawthorn and
other Rosacse.

C hucosperma, Pers. Disk dirty white ;
spores white. On various trees. Common.
Nemasporinn rosarum, Grev. Scot. Crypt.
Fl. t. 20.

C. fuynx, Bull. Disk dirty brown ;
spores' pale. On Willow branches. Very
common.

C. orbicularis, Berk. Disk yellowish ;
spores pale vinous red. Upon small orange
gourds. Berkeley, Ann. Nat. Hist. i. pi. 7.
tig. G.

C. Hendersoni, Berk, and Broome. Disk
whitish ; spores large, dirty white. On
Dog-rose. Berk, and Br. Ann. Nat. Hist.
2 ser. V. 379.

C. pulveraccajPjcvli. Br.Flora=Ceutho-
spora 2^hacidioidvs, Desm.

BiBi.. Berkeley, Brit. Flor. vol. ii. pt. 2.
281, Cry])t. Bat. 331 ; Berk, and Broome,

Hooker's Jn. of Bot. iii. 319; Tulasne, Ann.
Sc. Nat. 3 s^r. xv. 375 {Ann. N. H. 2nd
ser. viii. 114) ; Ann. Sc. Nat. xx. 129 ;
ihid. 4 ser. v. 115 : Bot. Zeit. xi. 49 (1853).

CYTOBLAST. See Nucleu.s.

CYTOBLASTE'MA, Blastema, or
Protoplasm. — The amorphous proteine-
substance of which animal and vegetable
cells are more or less entirelj' composed.
See Cells, and Protoplasm.

CY'TODE.— A term applied by Hackel.
to an organism consisting of a simple lump
of sarcode = to our protoplast (185(3).

Bibl. Hackel, Oen. 3Iorph. i. 269.

CYTOLEI'CHUS, jSIegn.— A genus of
Acarina, near to Sarcoptes.

C. sarcoptoides, has the body rounded,
the rostrum obtuse, and the tarsus of the
2nd pair of legs with a short cirrus directed
upwards or outwards. In the air-sacs and
bronchi of the Gallinae.

Bibl. Megnin, Parasites, 15.3.

D.

DACRY'MYCES, Fries.— A genus of
Tremellini (Ilymenomycetous Fungi), con-
sisting of lobulated gelatinous bodies grow-
ing upon wood. D, stillatus, a very com-
mon species on moist rotting wood, is
orange, turning brown when dried. Tu-
lasne has pubhshed some curious ob-
servations on thi^ genus, showing that the
spores produced on the basidia of the
external hymenial layer, are of two kinds ;
of which one kind germinates, while the
other produces minute stalked bodies, one
from each chamber of the septate spore,
destitute of gerrainative power {spermatia?)
(PI. 27. fig. 5).

]3iBL. Berkeley, Hooh. Brit. Fl. v. pt. 2.
210 ; Criipt. Bot. 353 ; Greyille, Sc. Crypt.
Fl. pi. 1.59 ; Tulasne, Ann. Sc. Nat. 3 kr.
xix. 211, pi. 12 & 13.

DACTYLI'NA,Nyl.— A doubtful genus
of Lichens.

D. arctica, Hook. , a singular fungus-look-
ing plant, inhabits Arctic America.

Bibl. Leighton, Linn. Jn. ix. 192, pi. 2.
figs. 11-17.

DACTYL'imi,Nees.— Agonus of Muce-
dines (Hyphomycetous Fungi), nearly allied
to Trichothccium, consisting of moulds
gi'owing over deca)'ing plants. Fries refers
Corda's species of Dactylium to Dendry-
phium. OnQ species, Dactylium ooyenum,
Moutagno; is remaa-kable for its place of

DACTYLOCOCCUS.

[ 235 ]

DAPHNELLA.

15o.

occurrence : it grows upon the surface of
the membrane within the shell of the eggs
of fowls and oth(>r birds. It
does not appear to have been
observed in this country ; but
several foreign writers have
investigated it ; and from the
experiments made by Spring
and Wittich, it appears that
the spores pass through ori-
fices existing in the shell, and
germinate in the interior,
often in the air-chamber. A
full account of this plant, and
of the literature, is given by
Ch. liobiu. Many of the
species are undoubtedly coni-jj^p^yu^j,^^ ^t^^^^
diiferous forms of SphcericB a fertile flla-
(Tulasue, Carpoloqia). See ment with septate
Dexdryphium and nELJiiN-«i;°;;-;^^^^_i'°'' its

THOSPORir JI. British spe-Magn.200 diams.

cies :

D. pyriforme, Fr. On mouldering stems
of herbaceous plants.

Z>. macyosporum, Fr. On rotton wood,
leaves, and fungi.

D. dendroides, Fr. On decaying agarics,
&c. Very common. Grev. Sc. Crypt. Fl.
pi. 12G. fig. 1.

D. obovatum, Berk. On willow twigs, in
damp. Aim. Nat. Hist. vi. pi. 14. fig. 26.

D. s])hcerocephalum, Berk. On dead ivy-
twigs, I. c. fig. 27.

D. teiuUum, Fr. On moss.
BiBL. Berk, in Hook. Brit. Fl. v. pt. 2.
345 ; A7in. N. H. tit supra ; Berk, and
Broome, Ann. N. II. 2 ser, vii. 102 ; Robin,
Parasites, 2nd ed. 543, pi. 2. figs. 5 & 6 ;
Fries, Syst. Myc. iii. 414 ; Summa Veget.
491.

DACTYLOCOCCUS, Nag.— A genus of
PalmeUaceous iilgie, allied to Cliaracium
and Ilydrianum.

Char. Cells oblong or fusiform, free, 2-8
together, then separating. Two species,
one green ; among other Algce, or on the
side of pools ; about 1-2500" long.

BrBL. Nageli, Einz. Aly,- p. 80 ; Eaben-
horst, Fl. Ah/, iii. p. 46 (fig.).

DACTYLOP'ORA, Lam.— Regarded by
some as one of the Foraminifera imper-
forata ; but by others as belonging to the
calciferous Algas. The simplest fi)rm pre-
sents a set of sac-like chambers, side by
side, for a part or the whole of a circle,
with their mouths in one direction along
the inner median line. Various modifica-
tions lead to the structure of a cylinder of

such rings, with interspaces, thickened
walls, and subsidiary cavities. The simple
forms (Z>. eruca, PI. 23. f. 53) live in the
tropical seas. The more complicated species
are of Tertiary age in France, Italy, and
San Domingo ; D. reticulata (PI. 23. f. 54)
is one of these.

BiBL. Parker and Jones, Ann. N. II.
ser. 3. 473; Carpenter, For. 127;Gumbel,
Ahh.bay. AJcad. 1872.

DACTYL'OPUS, Clans.— A genus of
Entomostraca, order Copepoda.
I), tishoides. Marine.
BiEL. Claus, Copepod. 127 ; Brady, Trans.
North umherland.

DALTO'NIA,Hook. andTayl.— A genus
of Pleurocarpous Mosses, the species given
being restored here on account of the struc-
ture of the leaf ; while D, heteromalla of
Hooker goes to Ilypnum on the same
ground.

D. splanchnoides, Hook. andT. = IIookeria
splanch. Hook.

DAM^'US, Koch. See Belba.
DAM'MARA-" 6^M?»."— The resin of
Dammar a australis, N. O. Piuacese. It is
often used, dissolved in benzole, as a
varnish ; and as it dries quickly, it is useful.
It is also largely used as a substitute for
Canada balsam ; but we prefer the latter.
DAN^'A, Smith.— A genus of Marat-

Fig. 156.

Dausa.
Part of a pinnule with so;i.
Magnified. 5 diameters.

tiaceous Ferns,' whence thefamilv is some-
times called also Danseaceae. Tropical Ame-
rica.

12 species.

BiBL. Hooker and Baker, Syn. 442.

DAPH'NE, L. See Thymeleace^.

DAPHNEL'LA, Baird.— A genus of
Entomostraca, of the order Cladocera, and
family Daphniadre.

Char. Inferior antennse very large, pos-
terior branch two-jointed only.

DAPHNIA.

[ 236 ]

DASYA.

D. Winf/n (PI. 20. fig. 27). Fresh-
water.

BiBL. Baird, Brit. Entomos. 109.

DAPH'NIA, Miill.— A genus of Euto-
mostraca, of the order Cladocera, and family
Daphniada3.

Char. Head produced into a more or less
prominent beak ; superior antenuse situated
beneath the beak, either one-jointed or con-
sisting of a minute tubercle with a tuft of
short filaments ; inferior antennae large and
powerfid, two-branched, one branch three-
jointed, the other four-jointed; five pairs
of legs.

Valves of the carapace finely reticulated,
and terminated below by a longer or shorter
serrated spine. Anterior branch of inferior
antennas (PI. 20. fig. 286) fom'-jointed, first
joint very short; from the end of the third
a long filament arises ; and the fourth joint
is terminated by three others ; posterior
branch three-jointed, the first and second
joints sending olFa long filament, the third
terminated by three of them ; the filaments
ai-e jointed near the middle, and usually
feathery. Eye spherical, with about twenty
lenses. Labrum (PI. '20. fig. 35) flattened,
and with a large hairy lobide at the end.
Mandibles (PL 20. fig. 34) consisting of a
fleshy -looking body, bent inwards near the
end, and terminated by numerous minute
teeth. Jaws (PI. 20. fig. 36) composed of a
strong body terminated by fom- horny spines,
thi'eeof which are curvedinwards. Legs five
pairs, those of the first pair in the female
(PI. 20. fig. 29) three-jointed ; upon the
outer edge of the second joint are three
small projections, each with four or five
long jointed setae ; terminal joint very
small, and with one or two similar setae ;
the setse not plumose. In the male they
are more slender, with a strong claw at the
end of the second joint, wliile the seta
arising from the terminal joint is very long,
nearly the length of the body, and floats
outside the shell.

The second (PL 20. fig. 30), third (fig. 31),
and fourth (fig. 32) pairs of legs are bran-
chial and somewhat similar, tlie joint fur-
nished with jointed and mostly plumose
setae, and a branchial plate also giving oft'
numerous plumose setaj. The fifth pair of
legs (fig. 33) are three-jointed, the portion
con-espiiudingto the branchial plate rounded
and without filaments; above this is a
curved, jointed, and plumose spine, the
third and fourth joints forming finger-like
processes springing from the lower end of

the leg, with two or three plumose setae.
The branchial legs are constantly in motion
during life; and this gives rise to the
quivering appearance seen in the Daphnice
with the naked eye or a simple lens.

The ova on then* escape from the body
become lodged between the back of the ani-
mal and the shell, where they remain until
completely hatched ; but at certain seasons
of the year ephippial or winter ova (PL 20.
fig. 37) are produced (Entomostkaca).

According to Lubbock's observations, the
latter only are true ova ; although both
kinds become hatched and perfectly deve-
loped, this may occur without impreg-
nation.

Seven Biitish species of Daphnia are re-
cognized : some of them may be found in
almost every collection of water, which they
frequently colour.

D.pulex (PL 20. fig. 28) (common water-
flea). Valves oval, their dorsal margin not
serrated ; head large, rounded above and in
front ; superior antennae (PL 20. fig. 28 a)
very small ; filaments of inferior antennae
plumose ; posterior portion of abdomen with
four projections at its curve, the first pro-
longed and bent upwards ; below these are
two jointed filaments ; the end portion has-
two dentate arches, and
terminates ^

hooks.

Some other species are
common ; but their essen-
tial characters have not
been briefly expressed.

BiBL. liaird, Br. En-
tom. 80; Lubbock, Ajin.
N. II. 1857, XX. 257 ;
Leydig, Daphnid. 18G0;
Weismann, Daphnidcn,
1877, and Zeitschr. rciss.
Zool. 1876, 7.

DAPtWINEL'LA,
Brady, ( = Poh/chelcs, B. ).
— -A genus of Ostracode
Entomostraca.

1 British species: D.
Stevensoni.

BiBL. Brady, Ann.
N. H. ssr. 4. vi. 2o.

DA'SYA, Ag.— A ge- _,

nus of Khodomelaceae Dasya Kiit/.injjiana,

(Florideous Wxta), con- «-ithasti.-hiaiuii.

^. .. ,, , ,., p ,., auil two rows of

sisting ot tulted hlamen- ■ tetrasiwrcs.

toUS sea- weeds, of a red, Magnified .50 dia-

brown, or purple colour, meters,

growing on rocks near low-water mark.

in two strong

DASYDYTES.

[ 237 ] DEGENERATION, FATTY.

The principal filaments are stoiitisli,
branclied,audclot]iod with branched raniules,
upon which arc borne the sticJtidia contain-
ing tetraspores (fig. 157), or ceraniidia con-
taining spores, on distinct plants. Four
British species are recorded, of which D.
coccinea and V. Arhuscula (PI. 4. fig. 9) are
the commonest.

BiBL. Harvey, Mar. Alqce. 93, pi. 12 B ;
Phyc. Brit. pi. 40, :?24, 22o & 25-3.

i)ASY'I)YTES, Gosse.— A genus of Ro-
tatoria, of the family Ichtliydina.

Char. Eyes absent ; body furnished with
bristle-like hairs ; tail simple, trvuicate.

D. (fiiuiathrix. Hairs long, each hair
bent at an abrupt angle ; neck constricted ;
length 1-146" ; fr. wat.

IJ. antennifjer. Hair short, doAvnv ; a
pencil of long hairs at each angle of the
posterior extremitj^ of the body ; head with
two club-shaped organs resembling antennae ;
length 1-170".

BiBL, Gosse, Ann. N. H. 1851, yiii. 198.

DASYGLCE'A, Thwaites.— A genus of
OscillatoriacejB (Confervoid Algaj).

D. amorpha (PI. 8. fig. 11) forms a shape-
less gelatinous stratum, consisting of curled
and entangled filaments, with very large
sheaths, open at the ends ; in marshy places.

BiBL. Eiuj. Bot. Supp. 2941; Kiitzing, <S)j,
Alq. 272 ; Tah. Phjc. Cent. i. pi. 72. fig. 2.

DATE.— The fridt of the Date-palm,
PJwenix clactyJifcra, N. 0. Palmace?e.
Roasted dates are used to adidterate real
coiFee ; a so-called date-coffee is also manu-
factured from the entire fruit, or from the
seed (perisperm) only. The principal tissues
of the latter are represented in PI. 2. fig. 9.

DAVAL'LIA, Sm. — A very large genus ;
tropical.

BiBL. Hooker, Sijn. 88.

DAVALL'IE.E.— A family of Poh-po-
diaceous Ferns.

Fig. 158.

Fig. 159,

Davallia pyxidata
A pinnule with sori. A sorus with the

Magn. 5 diam.

indusium cut open.
Magn. 15 diam.

Davallia. Sori globose or elongate, intra-

or sub-marginal ; indusium terminal on the
veins ; somewhat urn- or cup-shaped, the
mouth truncated (figs. 158 and 159), apex
free ; veins pinnate.

Cijstopteris. Sori globose, on the back of
the veins ; involucre membranous, sub-or-
bicular, inserted by its broad base under the
sorus, which at the beginning it covers like
a hood ; fronds two or three times divided,
thin, veins free.

DEGENERATION, FATTY.— The ab-
normal deposition of free fatty matter in the
histological elements of animal bodies.

When, from whatever cause, the iiormal
functions of the morphological element of
a tissue — cells, or the secondary deposits
formed in them — become languid or inter-
rupted, free globules of fat or oil become
deposited in them ; and as this fatty matter
increases in amount, the tissue loses to a
greater or lesser extent its natural vital and
physical properties ; hence it is said to be in
a state of fatty degeneration. The discovery
of the fattj' degeneration of tissues is pro-
bably one of the most valuable fruits of
microscopic study in regard to medical
science ; for it has shown us that maladies
supposed formerly to arise from too great
abundance of the circulating fluid, have really
had their origin in a decayed state of the tubes
or vessels in which the fluid was contained,
and that the natural process of human decay,
as it is called, is a morbid process or disease,
probably to a certain extent as remediable
or preventible as many other diseases to
which man is natiu'ally liable. Here is
indeed a matter of deep interest.

In addition to the deposition of fat within
the elements of a tissue undergoing fatty
degeneration, amorphous finely granular
proteine-matters are sometimes found : oc-
casionally also brown, yellow, red, or black
granular pigment is met with (pigmentary
degeneration), together with amorphous or
crystalline calcareous salts, as the carbonate
and phosphate of lime &c. (calcareous de-
generation) ; sometimes the fatty matter is
crystalline, it then generally consists of
cholesterine.

Fatty degeneration of cells is well seen in
those of the liver when undergoing this
change. In the noi-mal state, these as well
as most cells, except those of true fatty tis-
sue, contain merely one or two very minute
or no globules of fat, — whilst in the dege-
nerated tissue they contain a considerable
niunber of larger or smaller globides (fio-.
160). At the same time, the cell- walls and

DEGENERATION, FATTY. [ 238 ]

DELESSERIACEyE.

nuclei become lliinner and paler, or atro-
phied. A similar state to that T\-hich is
abnormal in man, is normal in the lower ani-
mals. Sometimes the substance intervening
between cells becomes degenerated^ and thus

Fi^. 160.

CeEs of the human liver; a, nearly normal cells; 6,
cell with pigment granules ; c, cells containing fatty
matter.

Magnified 400 diameters.

we have intercellular fatty degeneration
(PI. 38. tig. 16). Other instances of fatty
degeneration are noticed under the respective
heads of the tissues kc:, as the Graafian
vesicles and the cells of the corpora lutea
(Ovary), the epithelia of the mucous and
serous membranes, and of the various glands,
the vessels, the exudation-corpuscles of in-
ilammation, the muscles, &c.

The fatty degeneration of the capillaries is
represented in PI. 38. fig. 13. In the larger
blood-vessels, when reaching a more ad-
vanced degree, it forms atheroma.

It might appe.ar paradoxical to regard the
presence of numerous fat-globules, in such
instances as the cells of cancer, and the
exudation-cells of inflammation, where the
vital processes are so evidently augmented,
as indicating a state of degeneration. But in
these, as in other instances, the functions of
the cells, after the latter have attained their
full development, cease, and the cells un-
dergo degeneration and decay.

The free fatty matter is probably derived
in general from the liberation of that pre-
viously dissolved in the contents of the
cell ; but it may be produced bj^ the for-
mation of fatty nuitter from the proteine or
other constituents of the cell-contents. It
is curious that portions of the llesh and
other proteine-components of one animal,
when kept in the peritoneal cavity of another
living animal, will undergo fatty degenera-

tion. The formation of adipocere seems to
be an instance of post-mortem fatty dege-
neration.

Amyloid degeneration is noticed under
Amyloid.

BiBL. Virchow, Path. Cell. 1861; Wedl,
Path. Hist. ; Forster, Spec. Path. Anat. ;

d. Wiss. z. Gottin-
ix. 309); Green,

Wagner, Nach\ d. Ges

qen, 1851 {Chem. Gaz

'Path. 31, 1871 ; Riudfleisch, Lehvh. Geweh.

187-8, 46.

DELAVA'LIA, Brady.— a genus of En-
tomostraca, order Copepoda.

D. imludris. Northumberland.

BiBL. Brady, Trans. XorthuinherlandSi-c.,
Si Copepoda (Ray Soc).

DELESSE'PJA, Lamx.— Agenus of De-
lesseriacete (Florideous
Algae), consisting of
sea-weeds with a flat,
membranaceous, rose-
coloured frond, having
a percurrent midrib,
growing on rocks or
on other larger Algte,
mostly from 2 to 8
inches high. Six spe-
cies are described as
British, most of them
common. The leaf-like
lobes of the frond arise
from a kind of stalk, or
from the midribs of
older lobes. The tex-
ture is densely paren-
chymatous throughout.
D. sanyuinea (PI. 4. fig. 5) ripens its fruit
in the winter ; and then the membranous
part of the fronds decays, leaving the midribs
clothed with tufts of the sporophijUs or leafy
lobes containing the tetraspores (fig. 161),
and stalked coccidia cont.aiuing the spores.
The fructification is somewhat similar in
D. alata, while in D. sinuosa the coccidia
are immersed in the frond, and the tetra-
spores in cilia-like processes fringing its
margin ; and in 1>. Hypocjlossum the coc-
cidia are seated on the midi'ib, and the
tetraspores arranged in longitudinal linear
rows like sori on each side of the midrib.

BiBL. Harvev, Mar. Algce, 113, pi. 16 A;
Phyc. Brit, pis! 2, i>6, 83, 151, 247, 259;
Greville, Alt/. Brit. pis. 72-74, 76.

DEL1-:SSERIA'C1LE.— A family of Flo-
ridete. Rosy or purplish red, or blood-red
sea-weeds, with a leafy, or rarely filiform,
areolated, inarticulate frond, composed of
polygonal cells. Lobes of the frond deli-

Delesseria sanguinea.
Midribs of fronds in win-
ter bearing sporophylls.
If at. size.

DELTOMONAS.

[ 239 ]

DEMATIEI.

cately membranous. Fructification double ;
1. Conceptacles (coccidia) external, or half-
immersed, hemispherical, usuallj- imperfo-
rate, containinu" beneath a membranous ]U'vi-
carp a tuft of dichotomous filaments, whose
artu-ulations are tinally changed into spores.
•2. Tetmspores in distinctly definite s<vi,
either scattered through the frond or placed
in proper fruit-lobes or sporophylls.

Synopsis of British Genera.

Dehsseria. Frond leafy, of indefinite
form, -with a percurreut midrib.

Nitophjllxm. Frond\Q?Lij ,oi definite form,
without a midrib (sometimes traversed by
vague, vanishing nerves).

Flocaminm. Frond linear or filiform,
compressed, much branched, distichous ;
raunili pectinate, secimd.

BiBL. See the genera.

DELTOMONAS, Kent.— A genus of
Flagellate Infusoria.

Char. Bodies variable, wedge-shaped,
stalked ; flagella two, equal. Freshwater.
Multijtlication by longitudinal and trans-
verse division, and the breaking up of the
bodv into germs. In ponds. (Kant, Inf. 283.)

DEMATIET.— A family of Hyphomy-
cetous Fungi, growdug on the dead parts of
plants, and characterized by the mostly
septate spores being attached to rigid thick-
walled filaments, which are continuous or
septate.

According to the observations of Tulasne,
many of the supposed genera of this family
are merely conidiiferous states of Asconi)^-
cetous Fungi ; for instance Chidosporium.
We enumerate them here according to the
older arrangement, as their history is not
yet fully cleared up.

Synopsis of British Genera.

Cephalotrichum. Fertile filaments stalk-
like, erect, septate, tenuinating in a globose
capitule formed by radiating forked or
ternate branches bearing globular spores
at their tips.

Sporocybe. Filaments rather fibrous,
subrdate, capitate, bearing simple spores
conglobated into a terminal head.

(Edemium. Filaments rigid, erect, al-
most continuous, or annulated, bearing at
the sides globular masses of spores.

My.rotrichum. Filaments erect, scarcely
septate ; fertile branches crowned by globules
of heterogeneous conglutinate spores.

Helminthosporium. Filaments erect,
simple, septate ; spores traasversely septate.

Bolacotricha. Filaments simple, uni-
formly articulate at the apex ; spores con-
glomerated, large, globular, shortly stalked,
contents distinctly granular.

Triposporinni. Filaments erect, sep-
tate, sterile branches solitary, more or less
spreading ; fertile branches shorter, bearing
at the tips solitary, stellate, mostly very
shortly stalked spores.

Helicosporium. Filaments erect, subu-
late, closely septate, continuous and dia-
phanous at the summit ; spores thread-like,
septate, spirally coiled, then expanding
themselves with elasticity.

Cladotrichum. Filaments erect, septate,
branched ; branches and branchlets bearing
septate spores at their tips.

Dematiiim. Filaments erect, septate,
with verticiliate branchlets below, simple
and whip-like above ; spores crowded on the
apices of the ramules.

Cladosporiiwi. Filaments erect, septate
above, bearing the spores arranged in rows
forming short moniliform branchlets.

Macrosporium. Filaments suberect, sep-
tate, delicate, evanescent, bearing erect,
stipitate spores, with many transverse and
usually some longitudinal septa.

Arthriniiwi. Filaments tufted, suberect,
annulate, with opaque thickish septa ;
spores fusiform, septate, large.

Camptoum. Filaments as in the pre-
ceding ; spores ovate, cm-ved, small.

Arthrobotrymn, Common stem com-
posed of jointed filaments. Spores large,
radiating, so as to form a little head, dark,
septate.

Dendryphiiim. Filaments free, jointed,
simple below, branched above ; branches
and branchlets often monilioid ; spores sep-
tate, acrogenous, concatenated.

Periconia. Stem composed of fasci-
culated compacted filaments ; head globose ;
spores fixed to the free tips of the fila-
ments.

Haployraphiuni. Filaments jointed, fi'ee,
black ; spores concatenate, liyaline.

Monotospora .' Filaments free, black,
bearing one or rarely two (by division)
large, black, subgiobose spores at their
tips.

Helicoma. Filaments erect, dark, jointed,
bearing on their sides pale, flat, spiral
spores.

Polythrincium. Filaments moniliform ;
spores springing from the midst of the fila-
ments, didymous.

Gonatosporimn, Filaments erect, jointed,

DEMATIUM.

[ 240 ]

DEMODEX.

thiclieiied at the articulatious ; spores
irreg-iilarly bicouical, somewhat ai)gular,
attached in whorls.

Sporodum. Filaments erect, jointed;
threads of inarticulate spores moniliform,
seated towards their base.

Allied or uncertain Oenera.

Blasfotrichmn. Pedicels ascending or
floating, very much branched, continuous ;
spore.s oblong, transversely sei)tate.

Stachyohotrys. Pedicels branched, &&\\-
tate ; branches crowded at the tips with
whorls of niammillary very sliort branchlets
formiug a capitulum ; spores didymous.

Helicotrichum. Filaments creeping,
branched, septate only at the tips ; spores
spiraliv curled, somewhat septate.

DEMA'TIUM, Pers.— A genus of Dema-
tiei (Hyphomycetous Fungi), groAving upon

Fig. 162.

Fig. 163.

Fig. 164.

Dematium griseum. Magniiled 200 diameters.

dry leaves, bark, &c., distinguished by the
sporiferous branchlets arising closely toge-
ther near the base of the erect filaments.
British species :

D. yrisemn, Pers. (figs. 162-4). On
rotten hazel-stumps. C/xstopsis Wauchii,
Grev. Sc. Crypt Fl. pi. 236. See Echino-

BOTRYUM.

BiBL. Berk. Hooh. Brit. Fl. v. pt. 2, 338 ;
Ann. N. H. i. 260, vi. 435; Grev. /. c. ; Fries,
Sum. Vc(/. 499 ; Corda, Ic. Fung. i. pi. 4.
figs. 242,' 243.

DEMO'DEX, Owen (Simonia, Gerv.).—
A genus of Arachnida, the exact systematic
position of Avliich is doubtful, although
usually placed in the fixmily Acarina.

Chcu: Legs terminated by two claws
(only one, Beck), no acetabula ; abdomen
annidose.

D.folUcHhntm (PI. 6. fig. 42), the Ava-
rus, Simouia, or Entozoon foUiculormn of
some authors, inhabits the sebaceous and

hair-follicles of the human skin. The mi-
nute size of the various parts renders it ex-
tremelv difficult to isolate them. It varies
in leng-th from about 1-150 to 1-50".

At the anterior part of the body are two
two-jointed organs (PI. 6. fig. 43rt), the basa
joint longe.st, the distal smallest, and ter-
minated by a strong claw ; these appear
to represent maxillary palpi. Between
these are two narrow elongated organs (fig.
43. i), the mandibles. Behmd these is a
triangular labrum (fig. 43 c) ; a labium has
also been described.

Above or upon the basal joint of the palpi
are two minute tubercles, one on each side
(fig. 43 d). Similar tubercles are seen upon
the dorsal surface of the thorax, between
the second and third, and the third and
fourth pairs of legs.

On each side of the thorax are four pairs
of very short conical legs ; these are appa-
rently three-jointed, and marked by irregular
fine transverse stria).

The abdomen is longer than the thorax,
tapers posteriorly, and exhibits indications
of transverse rings, in the form of numerous
delicate transverse lines.

These animals may be obtained by press-
ing out the contents of the folhcles existing
upon the sides and alte of the nose, especially
Avhen these appear enlarged, whitish, and
exhibit a terminal black spot. A drop of oil
should then be added to the secretion, and
the whole allowed to macerate for some
hours at a gen'tle heat. Or the secretion
may be digested in a mixture of alcohol and
ether, to dissolve the fatty matter, and then
treated with soluticm of potash.

The secretion contains the ova, the young
animals, and the exuvia^. When contained
in the follicles, the tail is directed towards
their orifice.

Var. caninus occurs iu the pustules of the
skin of the dog afl'ected with the " mange."
The average size of this is less than that of
D.follicnlormn, amomitingto 1-150 to 1-lUO"
iu length. It does not appear to constitute
a distinct species ; for Gruby found that,
by inoculating the dog with the human
parasite, a disease resembUng, if not identi-
cal Avith, the mange was produced.

Var. cati, on the cat : about \ less than
I), follicidorum.

BiBL. Simon, 3Iidler'sArckiv, 1842, 218:
Owen, Hunt. Led. i. 251; .Gervais, Walck-
enai}r\^ Apthres, iii. 282 ; Wilson, Tr. Hoy.
Soc. 1844, 305; Tidk, Ann. N. H. 1844,
xiii. 75 ; Gruby, Ed. Mn. Jn. vii. 333 ;

DENDRITINA.

[ 241 ]

DERMANYSSUS.

Wedl, Path. Hist. 803; R. Beck, Ac/ir.
Micr. 6, pi. 24. fig. 1 ; Megnin, Parasites,
265.

DENDRITI'NA, D'Orb.— The nautiloid,
or compactly discoidal, conditiou of Pene-
ropUs. Common in tropical seas,

BiBL. Carpenter, Introd. For. 88.

DENDROCOME'TES, Stein.— A doubt-
ful genus of Acinetiua. The single species,
D. paradoxus (PI. 32. fig. 36), is supposed
by Stein to constitute the resting stage or
Acineta form of Spirochona yeminipara. It
is found upon the gill-plates of Gammai-us
pulex.

BiBL. Stein, Siebold Sf Kdlliher''s Zeitschr.
1852, iii. 492 ; id. Infm. 205 ; Kent, Inf.

DENDRO'MONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Bodies pyriform, obliquely trmi-
cate, single at the ends of a rigid homo-
geneous branched pedicle ; flagella two ; one
long, and the other short, lateral. Fresh-
water. 2 species. (Kent, Inf. 265).

DEXDROSO'MA, Ehr.— A genus of
Ehizopoda, of the family Acinetina.

Char. Consists of a thicli branched pedicle,
fixed at its base, the branches supporting at
their ends numerous bodies, a little larger
than the pedicles, each resembhng an Ac-
tinophrys.

D. radians. Bodies conical, thick, soft
and smooth, alternately branched; branches
iucrassate and tentaculate at the ends. Size
1-96' '. Freshwater.

BiBL. Ehrenberg, Infus. 316; CI. &
Lachni. Inf. iii. 140 (fig.).

DENDRYPHIUM, Walb.— A genus of
Dematiei (Hyphomycetous
Fungi), consisting of moidds
gi'owing over dead herba-
ceous plants, nearly related
to Dactyliuni ; but there are
often several spores chained
together at the tips of the
branches; perhaps not di-
stinct from Brachycladium,
Corda,whose species of Dac-
tylium (fig, 165) are brought
under this genus by Fries.
British species :

D. curtttm, Berk, and
Br, On dead stems. Ann.
N. H. 1851, vii. pi, 6. fig. 9,

D. Iaxii7n, Berk, and
Br. On dead stems. L. c.
fig. 10.

D. yriseum, Berk, and Br. On dead stems
L. c. fig. 11.

Dendryiihiiuu fu-

mosum.
JMagn. 200 cliams.

BiBL. Berkeley and Broome, I. c. 176,
pi. 6 ; Fries, Siimrna Veqet. 504.

DENTALI'NA, D'Oibigny.— The bent,
oblique, and somewhat excentric varieties
of Kodosaria pass under this name for con-
venience rather than for zoological reasons.
Innumerable modifications of these curved
and tapering stichostegian Foramijiifera oc-
cui' in all formations from the Carbonifer-
ous to the Tertiary, and abound in existing
seas. D. communis, D'Orb, (PI. 23, f. 33)
is the type, and has persisted the longest of
any.

BiBL. D'Orb. For. Foss. Vien. 1846;
Williamson, Pec. For. 17 ; Morris, Brit.
Foss. 34 ; Carpenter, Foram. 163 ; Jones,
Parker, and Bradv, Moiioy, Foram. Crag,
Pal. Soc. 1866, 53,"' &c,

DENTALINOP'SIS, Reuss.— A sticho-
stegian Nodosarina, commencing in its
gi'owth as a Phabdoyoniuni (OrthocerincC),
and continuing as a Dentalina. Only fossil ;
Cretaceous,

BiBL, Reuss, Sitz. Ak. Wien, xHv, 367.

DENTICEL'LA, Ehr. See Biddulphia.

DENTIC'ULA, Kutz,— A genus of Dia-
tomacese.

Char. Frustides free, single or binate,
straight, oblong or linear in front view ;
valves elliptical or narrowed at the ends,
transversely striated. Freshwater.

Striae mostly coarse, not resolvable into
dots (costse) ; valves -^dthout a median fine
or nodules ; ends of the strife \nsible at the
margins of the front view of the fioistules ;
no internal septa.

Five British species. Seven Em'opean
species ; one fossil (California).

D. ohttisa (PL 16. fig. 25 : d, front view ;
c, valve). Valves lanceolate, attenuate and
obtuse at the end ; length 1-830".

The other species differ principally iu
size ; D. sinuata is undulate in side view.

BiBL. Kiitzing, 6'/;, Aly. 11 ; Smith, Br.
Diat. ii. 19 ; Rabenhorst, Fl. Aly. i. 114.

DEPA'RIA, Hook.— A genus of Dick-
soniseous Ferns, with stalked indusia, shaped
like ancient flat' goblets (fig. 166, p. 242).
Five very rare tropical species.

BiBL, Hooker, Syn. 56,

DEPA'ZEA, Fries, See Spimieia,

DEPOSITS, URINAR Y. See Urine.

DERMALEPCHUS, Koch = ANALGES
(Muii-av, Fcrnt. E7it. 327).

DERMANYS'SUS, Duges,— A genus of
Arachnida, of the order Acarina, and family
Gamasea.

Char. Body mostly soft ; palpi, the fifth

DERMANYSSUS.

[ 242 ]

DESMIDIACE^.

Fig. 166.

Deparia prolifera.

Borus enc'osed in the stalked indusium.

Magnified 25 diameters.

(last) joint smallest ; labium acute ; mandi-
bles of the male chelate, external claw very
long ; of the female, ensiform ; anterior legs
longest ; eoxje approximate.

t), avmm (PL 6. fig. 24). Found in the
cages of tame singing birds and upon poul-
try. Body ovate-oblong, depressed, slightly
broader and sometimes emargiuate pos-
teriorly. The sixth joint of the legs (c) is
the longest. Mouth forming a kind of
moveable head attached to the under part
of the anterior margin of the body : it con-
sists of: — 1, a triangular labium, pointed in
front, and with two palpi (fig. 24 a*), the
second joint largest, the fifth smallest and
accompanied by a large but short, moveable,
external seta ; and, 3, the two mandibles
{b, of female ; of of male). Red or reddish
brown.

This species sometimes infests human
beings, producing a skin-disease, being de-
rived from fowls.

D. ves^jertilionis. Found upon the mouse-
coloured bat ( V. 7n)irinm). Rostrum nearly
as long as the palpi, broad or oval at the
base, narrowed in front, cleft longitudinally
above, and containing the two long and
slender mandibles.

I), pipisf relit. On the common bat ( V.
pipistrelli(s) .

D. hirtindinis. In the nest of the swal-
low.

1), (ialUn(S, On the common fowl.

D. Nifzfclni. In the nostrils of the goat-
sucker ( Caprimtdcjns).

Other species are found on the noctule
bat ( V. nocfula), the merlin, the turkey, the
snail, thf mouse, serpents, &c. ; and two on
the p;\}ony and the convolvulus.

BiBL. Duges, Ann. Sc. Nat. 2s^r. ii. IJJ ;

Gervais, WalcJcenaer^s Arach. iii. 222 ; Busk,
Mic. Jn. 1842, ii. 65 ; Kolenati, Sitz. AJc.
Wien, 18o9, 172 ; Murray, Ec. Ent. 169 ;
Megnin, Paras. 1880, 115.

DERMATIS'CUM, Nyl.— A genus of
Lichens, tribe Lecauorei, formed to con-
tain Endocarpon TTiunberf/ii, a native of the
Cape of Good Hope.

BiBL. Nvlauder, Enum. Gen. 116.

DERMATODEC'TES = Sarcoptes.

DERMES'TES, Linn.— A genus of Der-
mestidfe.

DERMES'TID^.— A family of Coleo-
pterous Insects.

The larvfe of these insects, which are
often minute, create great ravages amongst
dried skins, Airs, t^c. ; they also feed upon
feathers, bacon, books, papei', insects in
cabinets, mummies, itc. They are particu-
larly interesting to the microscopist, on ac-
count of the peculiar and beautifid structure
of certain of the hairs (PI. 1. fig. 1, a, b)
existing upon their bodies.

The hairs form three distinct tufts on
each side of the hinder segments of the
bodies of the larvae. The ordinary finely
spinous hairs on the rest of the body are
shown in c.

Although these hairs are generally called
the hairs of Dermestcs, it so happens that
this genus is almost the only one in the
species of which the hairs do not exist.

British gen. : Anthrenus, Attagenm, Me-
gatoma, Tiresia^, Dermesfes, and Trinodes.

BiBL. Westwood, Introd. i. ; Cui-tis, Br.
Insects, 682 ; Stephens, Manual, 142.

DES3LAREL'LA, Kent.— A genus of
Infusoria.

C7iar. Free, united laterally into rows ;
flagellum single, terminal, encircled at the
base by a collar. 2 species, 1 in fresh, the
the other in salt water ; length of bodies
4oVo". (Kent, Inf. 341.)

DESMARES'TIA, Lamx.— A genus of
Sporochnaceoe (Fucoid Algae), consisting of
oUve or broAvnish seaweeds, with repeatedly
pinnate, feathery fronds, from one to several
feet long, growing chiefiy between tide-
marks or in deep water. The characters of
the reproductive structures have not yet been
made out, as the species rarely fruit on om-
coast, although the plants are common.

BiiiL. Ilarvev, iHar. Aly. 23, pi. 5D;
my c. Brit. 49,' 115; Greville, Alg. Brit.
pi. 5. figs. 1 to 6.

DESMIDIA'CE.E (PI. 14).— A family of
Oonfervoid Alga;, consisting entirely of mi-
croscopic flexible org^anisms inhabiting fi'esh

DESmDIAOEiE.

L 243 ]

DESMIDIACEyE.

water, scarcely a specimen of which can be
foimd that does not contain some of them.
They occur in greatest abundance in clear
poofs in open exposed situations, the larger
species being generally found nearest the
bottom. Sometimes they adhere in large
numbers to aquatic plants, forming green
films investing them ; at others they rest as
a thick coating at the bottom of the water,
or lie intermingled with Confervpe, &c.

They are most striking objects under the
microscope, from the peculiarity, beauty,
and variety of their forms, their colom', and
their external markings and appendages ;
that which is most distinctive in their ap-
pearance is the bilateral symmetry, indica-
tive of the tendency to divide transversely
into two valves or segments. Each frustule
is in reality a single cell, as is shown by the
fact that the entire contents escape when an
orifice is made ; but in the generality of
the forms, a constriction, or more or less
deep notch, or a kind of suture exists in the
middle of the external cellidose coat. In a
few instances, such as Scenedestmis, the sym-
metrical form is absent ; in Pediastruin
(PL 14. figs. 48, 49) it is only indicated by
a notch on the outer side ; but a graduated
series may be formed, from those genera in
which this character is inconspicuous, to
those in which it is fully developed. Thus
in Closterium (figs. 40 to 45) and some spe-
cies of Penium, there is no constriction ; in
Tetmemorus (tig. 33), some Cosmaria (fig.
22), and Hyalotheca (fig. 1), it is quite evi-
dent, although but sHght ; in Didymoprium
and Desmidium (fig. 7), it is denoted by a
notch at each angle ; whUe in Splicerozosma,
Micrasterias (fig. 13), and some other
genera, the constriction is very deep, the
connecting portion foi-ming a mere isthmus
between the segments, which appear like
distinct cells.

The cells frequently exhibit external
waity or spinous processes (PI. 14. fig. 23),
and the cellulose coat (coloured blue by
means of iodine and sulphuric acid) presents
minute markings which, unhke those on the
siliceous envelope of the Diatomacese, are
always elevations. The cells are surrounded
by a more or less perfect and distinct
sheath, of gelatinous consistence, and very
transparent. In Hyalotheca, Didymoprium,
Sphcsrozosma, &c., this is very well defined
(PI. 14. figs. 1 to 6) ; but in other genera it
is more attenuated, and the fact of its
existence can only be discovered by its
preventing the contact of the cells. The

sheath of Hyalotheca often presents delicate
dark striae, which, if the gelatinous sheath is
not clearly seen, loolv like rigid cilia standing
upon the sm:face of the cell-wall ; these
appear to be either fissures in the gelatinous
sheath, connected with the breaking up of
the filamentous groups into single cells, or
they are referable to a fibrous disintegration
of the gelatinous sheaths, such as occurs in
many Oscillatoriace^.

The contents of the cells of the Desmi-
diaceee appear to resemble those of the green
Confervoids generally, in consisting of a
mass of protoplasm coloured green by chlo-
rophyll, and being entirely enclosed in a pri-
mordial utricle, which does not appear to be
adherent to the cellidose coat in mature
specimens. The contents of the cells con-
tain minute starch-granides as in the other
Confervoids, in the full-grown condition,
and in the zygospores.

It was stated some years ago by Focke,
that the internal surface of the outer coat
of Closterimn is ciliated ; and Osborne has
declared that the membrane of the endo-
chrome (primordial utricle) is ciliated both
on its inner and outer surface. These state-
ments are erroneous, as is shown under
Closterium.

The Desmidiaceas, at all events many of
them, have the power of fixing themselves
to external objects, and possess a feeble
power of locomotion, which is not produced
by the aid of cilia, and cannot be explained,
imless on the principles which have been
assumed to account for the same pheno-
menon in the Diatomace^. It enables
the Desmidiacese, when mixed with mud,
to make their way to the sm-face ; and they
will be foimd to travel and fix themselves
to that side of a glass vessel next the light.
In some instances, also, they retire beneath
the sm-face of the mud of pools ifcc. before
this dries up.

The Desmidiaceae, like other green plants,
evolve oxygen when exposed to the sim's
light.

The reproduction of this family exhibits
a number of very interesting and varied
phenomena. Four modes have been ob-
served; and some points connected with
the subject still remain to be cleared up.

The simplest kind of reproduction is by
cell-division, where each frustule divides
transversely into two. The manner in
which this takes place differs to some ex-
tent in its details in the various genera,
according to the form. Thus in Ciostemtm

e2

DESMIDIACEiE.

[ 244 ]

DESmDIACE^.

the parent-cell acquires a constricted ap-
pearance iu the middle, probably not by
actual constriction, but by the two halves
retreating from each other, Avhile a new
hour-glass-shaped prolongation of the mem-
brane is formed in the middle. It appears
probable also that the primordial utricle
first becomes constricted, since specimens
are met with in which this appears divided
into two portions in the line of the division.
The constriction of the outer cell-wall at
length becomes complete the halves sepa-
rate and the truncate new end of each then
grows out so as to restore the symmetry of
the new frustule. In such forms as Desmi-
dium, Didymoprium, &c., the di\"ision takes
place in a manner apparently resembling
that occurring iu the tilamentoas Confervte.
Here there is no necessity for the subsequent
restoration of sjTnmetry, as in Closteriuin. In
those forms where pau's of globular or ellip-
tical or aug-ular lobes are united by a narrow
neck (bipartite forms), the process of divi-
sion is very curious, and displays itself very
clearly. To produce two new symmetrical
frustules out of one, it is evident that two
new half-frustules must be formed, as in
Closterium ; but in the present cases the
foundations of the new halves are laid, and
theii' development often far advanced, before
the division of the parent is completed.
The central region of the isthmus expands
and displays two globular enlargements,
separated from each other, and from each
half of the parent, by a neck. These two
enlargements are the rudiments of the new
*haK-frustules;' and they increase in size
(PI. 14. fig. 11), gradually pushing the halves
of the parent-cell apart, until they form two
complete half-frustules, back to back, con-
nected by a short neck, at which point they
are sooner or later detached from one an-
other. In Sjjhcevozosma the cells thus pro-
duced remain connected in rows in a gela-
tinous sheath ; and this mode of division is
well illustrated by the cells iu various stages
sometimes seen in such filaments ; in Euas-
trum, Cosmarium,Staur<istrum, &c.,the new
cells separate, the old half-frustules taking
away each their new halves as new bi-
partite individuals. The membrane of the
nascent halves is very delicate, and at first
devoid of the characteristic markings and
processes ; and it often happens that these
are not completely formed before the division
is complete. Archer has described some
monstrosities of these new halves.

A second mode of reproduction has been

described by Caspary and Braun, in Pedi-
astrum. The contents of the parent-cells
become retracted from their walls, and
the whole transformed into a number of
active ciliated zoospores, which are dis-
charged within a delicate sac from the
parent, and after some time come to rest
and arrange themselves within this sac (PI.
10. %. 11) into a colony having the regular
pattern of the species, each zoospore be-
coming one of the notched frustules of the
group (see Pediasteum).

A third process, analogous to this, has
been observed by Priugsheim in the genus
Coelastrum, hkewise composed of grouped
families : here the contents of each cell are
divided into a number of portions, as if for
the formation of zoospores {still zoosjwyes),
but no motion takes place ; they acquire
cellulose coats, arrange themselves within
the parent according to the typical pattern ;
and then the wall of the parent-ceU splits
and peels off, leaving them as the founda-
tion of a new gxoup. Comiected with this,
is a phenomenon which has been observed
and figured in Closterium, by Focke, where
the entire green contents were only retracted
from the AvaUs, and broken up into a number
of green encysted globules (PI. 10. fig. .3B),
closely resembling the thick-walled resting-
spores or winter-spores of Volvox (PI. 7.
figs. 20, 34), &c.

The fourth mode of reproduction is by
what is called Conjugation, where two cells
of a single filament, or of two separate fila-
ments, contract an organic union, their cavi-
ties becoming contimious, and their contents
becoming blended to form the substance of
a zygospore. These are at first cellulose
vesicles filled with green and graniUar con-
tents, then- starch being converted into
fat ; by degrees they become brown or red,
and the coats become thickened. In some
genera the coats remain smooth : iu others
they acquire a granular, tuberculated or
even a spinous surface (PL 14. fig. 12),
these spines being either simple or forked.
Bodies exactly resembling these are found
fossil in flint, and are regarded as of the
same nature bj- Ralfs and others ; Ehrenberg
described them as species of Xaxthidium.
Li germination, the contents of the
zygospore escape as a thin-walled vesicle,
and become divided into a more or less
numerous brood of secondary cells,resembling
those of the parents (PI. 10. fig. 3 A d.).

The Desmidiaceae may be collected in the
same manner as is recommended for the

DESMIDIACE.E.

[ 245 ]

DESmDIACEiE.

Dr.vTOMACE-s:. Their preservation is a
difficult matter, as almost all the preser-
vative liquids alter them more or less.
Those producing the smallest amount of
change are Thwaites's liquid, Ralf s's liquid,
or simple camphor-water : but these liquids
always escape in time from the cells. A
few, for example Pediastrum,Kve unchanged
by concentrated solution of chloride of cal-
cium very gradually added, except that the
colour becomes rather paler, or solution of
acetate of potash ; moreover the cell-mem-
brane, upon the forms of which the
characters mainly depend, remains unal-
tered in all the kinds when kept in these
solutions. Many prefer glycerine, which is
really the best preservative medium ; in
some cases glycerine-jelly is used.
See Preservation.

Analysis of the Tribes and Genera. (PI. 14.)

I. CLOSTERiE-tE. Cells single, elongated,
never spinous, freqiiently not constricted
in the middle (sporangia smooth).
Closterimn. Cell crescent-shaped or arcu-
ate, or much attenuated at the ends, not con-
stricted in the middle (figs. 40-45, 57, 58).

Penium. Cell straight, not or very
slightly constricted in the middle, rounded
at the ends (fig. 36).

Tetmemorus, Cell straight, constricted
i the middle, notched at the ends (figs. 33,
34).

Docidium. Cell straight, constricted in
the middle, truncate at the ends (figs. 38, 39).

Spirotmiia. Cell straight, not constricted j
endochrome spiral (fig. 59).

II. CosMARiEiE. Cells single, distinctly
constricted in the middle ; segments sel-
dom longer than broad (sporangia spinous
or tuberculated).

Micrasterias. Lobes of the segments in-
cised or bidentate (fig. 13).

Euastrum. Segments sinuated, generally
notched at the ends, and with inflated pro-
tuberances (figs. 14 to 17).

Cosmarium. Segments neither notched
nor sinuated, end view elliptic, circular, or
cruciform (figs. 18 to 22).

Xanfhidium. Segments compressed,
entire, spinous (figs. 23 to 25).

Arthrodesmus. Segments compressed,
each with only two spines (fig. 27).

Staurastrum. End view angular, radiate,
or with elongated processes (figs. 26, 28-32,
and 56).

m, Desmidie^e. Cells united into an

elongated jointed filament (sporangia

spherical, smooth).

Geniculai-ia. Filament cylindrlcal,smooth ;
endochrome spiral (PI. 51. fig. .36).

Gonatozijgon. Filament cylindrical or
fusiform, smooth ; endochrome longitudinal,
wavy (PI. 51. fig. 37).

Hyalotheca. Filament cylindrical, ceUs
crenate (PI. 14. figs. 1, 2).

Didymoprium. Filament cylindi'ical or
subcylindrical ; cells with two opposite bi-
dentate projections (figs. 5, 6).

Desmidium. Filament triangular or qua-
drangular ; cells with two opposite bidentate
projections (figs. 7, 8),

Aptogonum. Filament triangular or plane,
with foramina between the joints (figs. 52,
55).

Sphisrozosma. Filament plane, margins
deeply incised or sinuated (figs. 9, 10).

IV. Ajstkistrodesiil^. Cells elongated, en-
tire, small, gTouped in faggot-like bimdles.
AnJcisirodesmus (fig. 47).

V. Pediastre^. Cells grouped in the
form of a disk or star, or placed side by
side in one or two short rows.
Pedtastrmn. CeUs forming a disk or star,

marginal cells bidentate (fig. 48).

Monactiyius, Cells as in Pediastrum, but
margbial cells uuidentate (PI. 36. fig. 28).

Scenedesmiis. Cells placed side by side
in one or two rows (figs. 50, 51, 53, 54).

Ccelastrtim. Cells forming a hollow sphere
(PI. 3. fig. 8).

Three interesting genera are described
and figiu-ed by Wallich from Lower Ben-
gal {Leuronema, Onychonejna, and Strep-
tonema).

Tetrachastrum, AxQh.e:\=Micrasterias,^i. ;
Triploceras= Docidium, pt. ; Lejitoajstine^na,
Arch.= Gonatozygo7i, De Bary; Spondylo-
siuin= Splicer ozosma, pt.

Eabenhorst places Cosmocladium among
the Palmellacefe.

BiBL. Ralfs, Br. Desmid, ; Ehrenberg,
Inf. ; Pritchard, Infus. ; Hassall, Ah/ce ;
Nageli, Einzell. Alg. 1849 ; Braim, Verjiing.
{Ray Soc. 1853); Focke, Phijs. Studien,
1848 ; Caspary, Bot. Zeit. viii. 786, 1850 ;
Pringsheim, Flora^\S&'2, 486 ; Hofmeister,
Ann. N. H. 3 ser. i. 1 ; Carter, ibid. 2 ser.
xvii. ; Thomas, Mir. Tr. 3 ser. ; Bailey
Smiths. C'ontr. 1854; Rabenhorst, Fl. Alg.
iii. 102 ; WaUich, Ann. N. H. 1860, v. 184,
273; Archer, Qu. M. Jn. 1860, viii. 85,
215, 235 ; Brebisson, Liste, 1856, 2 plates ;

DESMIDIUM.

[ 246 ]

DLLPTOMUS.

Sachs, Bot. 262; Notaris, Desmidiacee
ItalicTie, 1867: Delaporte, Desm. snhalp.
1877 (23 pis.).

DESmD'IUM, Ag.— A genus of Desmi-
diacese.

Char. Cells united into a brittle, regu-
larly twisted, triangular or quadrangular
filament, and two-toothed at the angles.

The filaments exhibit one or two dark,
oblique, wavy lines, arising from their being
twisted. In the side view of the cells, the en-
dochi'ome exhibits thick,frequently cleft rays,
corresponding in number -nith the angles.

D. Stvartzii (PI. 14. fig. 7; fig. 8, side
view of separate cell). Filament triangular.
Length ofjoint 1-2000 to 1-1660" ; breadth
of filament 1-630". Not uncommon. Spo-
rangia round or oblong.

D. quadraiu/ulatum. Filaments quadran-
gular. Length of joint 1-2400" ; breadth
of filament 1-600 to 1-450".

BiBL. Ralfs, Br. Desmid. 60; Kutzing,
Sp. Alfi. 190.

DESMOGONIUM, Ehr.— A

of

Diatomacese.

Char, Frustules those of Synedra united
into tablets, which are coherent by the angles.

D. Eiitzinyii. Submarine marshes; Ger-
many.

D. Gnjanense. Found in Asia, Africa,
and America.

BrBL. Ehrenberg, Mih'og. ; Eabenhorst,
Flor. Ah/, i. 142.

DEUtZ'IA, Thunberg.— A genus of Phi-
ladelphaceffi (Dicotyledonous Plants) re-
markable for the stellate hairs upon their
foliage (PL 28. fig. 26*), and the reticulated
membrane covering the seeds; both of which
structures form in-
teresting microsco-
pic objects. See
Haihs and Seeds,

DIACAL'PE,
Bl. — A genus of
Cyathe8e(Polypodi-
aceous Fems), with
globular indusia,
splitting open at
the top(fig.l67), and
containing spo-
ranges inserted on a
punctiform recep-
tacle rising from
the middle of the
vein. Hei'baceous ;
leaves tripinnate,
membranous. Native of Java, &c.

BiBL. Hooker, Sj/n. 45.

Diacalpe asplenioides.

Part of a pinnule with sori.

Magnified 10 diams.

DIACH^'A, Fries.— Age- Fig. 168.
nus of Myxomycetes, consist-
ing of perishable little plants,
growing over either living or
dead plants, with an elongated
membranous peridimu, wliich
falls oft' lilie a cap, and displays
a white reticidated capillitium
furnished with a floccose cen-
tral column, with interspersed
blackish-red spores.

Diachcsa diners from Stemo-
nitis in the peridium, the colu-
mella, and the habit of growth.

D. elegans, Fr. {Stemonitis,
Trentep.), the only species,
has been foimd in England,
upon the living leaves of the
Lily of the Valley &c. (fig.
168).

BiBL. Fries, Syst. Mycol.
iii. 155; Berk. A7in. N. II. i.

257 ; Corda, Ic. Fung. v. pi. 3. Diach^a elegans;
fig. 38. Magn. 25 diams.

DIADES'MIS, Klitz.— A genus of Dia-
tomaceas (Cohort Naviculese).

Char. Frustules navicular, closely united
into elongated biconvex filaments ; valves
with a median and terminal nodules.
Freshwater and marine.

The markings have not been satisfactorily
investigated.

D. confervacea (PI. 16. fig. 27). Breadth
of frustules (in front view) about half the
length; valves lanceolate, acuminate and
acute at the ends; length of frustules
1-960".

Eight species, some fossil.

BiBL. Kutzing, <S)j. ^?/7. 95; Rabenhorst,
Fhr. Alq. i. 259.

DIAMOND-BEETLE. See Cubculio.

DIAP'TOMUS, Westw.— A genus of
Entomostraca, of the order Copepoda, and
family Diaptomidae.

Char. Head distinct from thorax; inferior
antennae two-branched ; thorax and abdo-
men each of five segments ; foot-j aws un-
branched ; legs five pairs, the first pair with
two branches, one three- the other two-
jointed; three succeeding pairs with each
branch three-jointed ; external ovary single,
large, lying across the abdomen.

B. castor (PI. 20. fig. 38). Found in ponds
and slowly-running water ; common in spring
and autumn. Length about 1-8".

BiBL. AVestwood, Eyitom. Text-hook ;
Baird, Br. Fntom', M.-Edwards, Crust, iii.
427.

DIAS.

[ 247 ]

DIATOMACE^.

DIAS, Lillj. — A geuus of Copepoda (En-
tomostraca).

D. lonffiremis. Cumberland.

BiBL. Bradv, Copepoda {Ray Soc.) 5. 50.

DIASTOT()RA, Lamouroux.— A genus
of lufundibulate Polyzoa, of the suborder
Cyclostomata, and family Tubuliporidfe.

Distinguished by the iucrustiug, unde-
fined or foliaceous zoary ; and the alternate,
tubular, horizontal, immersed cells, with a
raised circular orifice.

D. ohelia. Crust thin, closely adnate.
Three other species.

BiBL. Johnston, Br. Zooph. 276 ; Gosse,
Mar. Zool. ii. 8 ; Hincks, Polyzoa, 457.

DIA'TOMA, Dec— A genus of Diato-
maceae (Cohort Fragilaripe).

Char. Frustules (in front view) linear,
sometimes cuneate ; at first united into flat
filaments, afterwards partly sepai-ating so
as to remain connected by the generally
alternate angles only, and thus forming a
zigzag chain.

Filaments either free or fixed by a stipes.
Frustules prismatic, without rittae ; valves
with transverse continuous strife (costae)
and intermediate finer striae, not always
visible by direct light ; ends of the striae
extending into the front \'iew.

Five British species :

D. vulyare (PI. 16. fig. 26 : a, side view ;
b, front view). Fixed by an inconspicuous
stipes; frustides rectangadar, oblong ; valves
elliptical, contracted and obtuse at the ends;
striae evident; length of frustules 1-430".
Freshwater.

D. ehngatuin. Frustules very slender,
slightly attenuated towards the middle ;
valves linear, evidently' striated, tumid
and roimded at the ends ; length 1-280".
Freshwater.

D. grande. Valves linear, constricted near
the rounded ends ; costae evident. Fresh-
water.

D. hycdinum. Filament of numerous
frustules; valves linear-elliptical, ends sub-
acxite, striae obscui-e. Marine.

D. minimum. Fnistules two or three ;
valves elliptical, ends roimded ; striae ob-
scure. Marine.

BiBL. Ralfs, Ann. N. II. 1843, xi. 449;
Kiitzing, Bac. ^' Sp. Alg. 16; Smith, Br.
Diat. ii. 38 ; Eabenhorst, Fl. Alg. i.

piATOMA'CEvE.— A family of Confer-
void Algae, of very peculiar character, con-
sisting of microscopic brittle organisms,
found in almost all fresh, brackish, or salt
water; sometimes forming a uniform yel-

lowish-brown layer on the bottom of the
water, at others adhering to various water-
plants, decaying stems, stones, &c., or scat-
tered between the filaments of Confervae
and marine Algas &c. They also occur
among Mosses, Oscillatorice, and on damp
ground.

The individual cells of the Diatomaceae
are called frustules or testules, and are fur-
nished with a coat of silica (Cytioderm).
This consists of two usually symmetrical
portions or valves comparable to those of a
bivalve shell, which are in contact at their
margins with an intermediate piece (the
hoop), variable in breadth, according to age
&c. When this is very narrow, it forms a
mere junction line, and is called the line of
suture ; and that aspect of the frustules in
which this is turned towards the observer
forms the front or front view : primary side,
Kiitzing; secondarv side, Rabenh. (PI. 15.
fig. 7 ; PI. 16. figs.^ 9 a, 30 b). That aspect
of the frustides in which the surface of the
valves is turned towards the observer, forms
the side or side-view of the frustules :
secondary side ; Kiitzing, primary side, Ra-
benh. (PI. 15. fig. 6; PI. 16. fig. 30 a).

_ The separate valves are of various forms :
circular, oblong, elliptical, linear, saddle-
shaped, boat-shaped (navicular), undulate,
sigmoid, &c. (Pis. 15, 16, 17); and their
surfaces exhibit various more or less delicate
sculpturings and markings, in the form of
bands, lines either parallel, radiate, or cross-
ing each other, and dots, or a cellular
(areolate) appearance.

These markings are in general not well
seen, and in some cases cannot be seen at
all, until the valves have been properly pre-
pared. They are of special interest, not
only on account of their extremely beautiful
delicacy and symmetiy, but because they
are used as tests for the quality of the
object-glasses in regard to angidar aper-
ture. The nature of the markings is de-
scribed under the individual genera ; and
the modes of viewing them will be spoken
of further on.

In some the hoop is a simple filament, so
curved or bent as to assume the form of
the section of the frustules, or the edges of
the valves (PL 15. fig. 11). In others, it is
broad, and marked like the surfaces of the
valves (PL 17. fig. 2 a). In others, again,
the hoops are numerous, flat, and arranged
like the leaves of a book, each with a round
or oval aperture in the middle, so that the
cavity of the frustules is divided into loculi ;

DIATOMACE^.

[ 248 ]

DIATOMACE^,

these frustules we shall distinguish as com-
pound (PI. 18. fig. 69).

During the process of multiplication by
division, which is almost always going on,
the annular siliceous, narrower or broader
band, or hoop, imdergoes an increase of
width, and the two valves are removed
some distance apart (PI. 15. figs. 7, 45 ;
PI. IG. fig. 1). Sometimes it consists of
two pieces, one overlapping the other.
Some of the valves are furnished with pro-
cesses, called cornua or tubuli (PI. 16. fig.
30 b) ; the surfaces of others are undulate,
producing the appearance of dark curved
or wavy lines or bands (PI. 16. figs. 22, 23,
24) ; sometimes curiously arranged lines,
(vittfe) indicate either imperfect internal
septa, the internal margins of the flattened
hoops, or certain inflections of the margins
of the valves (PL 1. figs. 14, 15 ; PI. 17.
figs. 17, 18).

In the young state of these organisms,
the endochrome or cytioplasm is imiformly
distributed; but after a certain time, it
becomes accumulated into various, usually
very regular and often elegant forms, and
minute granular globules are formed, trans-
parent vesicles become visible, drops of oil,
and vesicles tilled with granides, which at
first are motionless, but afterwards move
about as in the swanniug motion of the
Algse. Frequently a considerable nucleus-
like body is present in the middle of the frus-
tule (PL 15. fig. 33 a). As we have seen it,
delicate processes were visible arising from it.

The frustules of the Diatomacese are
sometimes surrounded by a transparent ge-
latinous sheath, frequently of great delicacy,
or contained in gelatinous simple or branched
tubes ; in some genera they are attached by
a stipes or stalk to water-plants &c.

Those Diatomacese which are not fixed
by a stipes, and especially such as are linear
or spindle-shaped, are capable of sponta-
neous motion ; they may be constantly seen
slowly moving across the field, or now and
then starting somewhat suddenly forwards,
moving mostly in the direction of their
length, sometimes receding, sometimes per-
forming a rotatory movement on their axis.
Those which are contained in numbers in
gelatinous tubes, like Mict/07iema (PL 19.
fig. 10), are capable of moving backwards
and forwards in these; and Thwaites de-
scribed a curious movement of the frustules
of Bacillaria parndoxa, where the frustules,
united in a band, slid backwards and for-
wards over one another.

The cause of this motion is undetermined.
It has been supposed to be produced by the
endosmotic changes connected with the
nutrition of the organisms ; but this is very
improbable, otherwise it woidd be met with
frequently in other minute unicellular or-
ganisms; moreover, the diffiisi on -move-
ments are far too slow and gentle to explain
them. No true vibratile ciUa have been
detected upon the Diatomaceee, although
Thwaites imagined, from the appearance of
currents in the water, that they exist on
Bacillaria. Some are not unfrequently
found bearing tufts of or fringed with rigid
cilia, like those often seen at the ends of
the filaments of Oscillatorics ; these woidd
seem to be formed like the fringes met with
in the Desmidiace?e, by a modification of
the gelatinous envelope; they never exhibit
motion.

It has more recently been supposed to
arise from the action of a delicate layer of
protoplasm investing the frustules, or pro-
truding through chinks between the valves
of the frustules at the suture. (H. L. Smith,
Jn. Mic. Soc. i. 1878-79.)

In placing the Diatomaceae among plants,
we assume an agreement between the frus-
tule of a Diatomacean and an individual cell
of any undoubted vegetable, such as Proto-
coccus ; and between the series of frustules
such as we find in Fragilaria (PL 16. fig. 33),
or Melosira (PL 17. fig. 5 a), and the cellu-
lar filament of a Conferva or a Zygnema.
This agreement does imdoubtedly exist ; and
the siliceous shell is really only a result of
the incrustation or permeation by silica of a
true vegetable cell-membrane, just in the
same way as takes place in the epidermis
of Equisetum. It is not yet ascertained in
either case whether the silica is outside or
in the substance of the cell-membrane ;
certainly it is not inside, as that would be
incompatible with the known phenomena of
division. It may be removed by hj-drofluoric
acid, leaving the basement membrane in
situ ; but this proves nothing. The proba-
bilities are that the substance of the mem-
brane is imbued with it.

In regard to the cell-contents of the Dia-
tomacese, there exists a layer of protoplasm
forming a primordial utricle, inside the cell-
membrane, and enclosing the rest of the
contents. In the coloured substance con-
stituting the mass of th^ endochrome the
chlorophyll is obscured by a yellow colour-
ing-matter, diatomine or phycoxanthine ; it
takes a green or greenish-blue tint with

DIATOMACE^.

[ 249 ]

DIATOMACE^.

sulphuric acid, and also often bj drying ;
and H. L. Smith has shown that it exhibits
the spectroscopic reactions of chlorophyll.
Oil-globules, soluble in ether, are also found,
sometimes of large size, in particular stages
of growth, probably representing here the
starch-grains found in other Confervoids,
or indeed the oil which occurs in them and
other plants in seasons of rest. No starch
has been detected in this family. A trans-
parent rounded nuclear body is often ob-
served in the centre of the contents.
Schmidt found in Frusculia salina, after
removing the oil by ether and the proto-
plasiui by potash, a substance identical iu
composition with the cellulose of Lichens.
This was probably derived from the organic
matter of the silicified membranes of the
frustules.

The ordinary mode of increase of the cells
of the Diatomacese is, like that of all other
vegetable cells, a process of division. In
Melosira, Isthnia, &c. this bears a close re-
semblance to the process which occurs in
Spiror/i/ra ; and it is only a modified form of
the same process that is found in the free
Diatomacete. It may be briefly described
thus : — the primordial utricle, enclosing the
contents, divides into two portions, which
separate from one another in a plane parallel
with the sides of the individual frustules ;
the two valves of the parent-cell gradually
separate from one another, remaining con-
nected by the simidtaneous gradual widen-
ing of the hoop. In the space thus afforded,
the two segments of contents secrete each
a new layer of very delicate, easily crum-
pled membrane without markings, which
ultimately becomes silicified over the sur-
faces, constituting two new half-frustules,
back to back, corresponding to and con-
joined with the two half-frustules of the
parent to form two new individuals. The
markings on the new valves are sometimes
different from those upon the parent. The
history and ultimate fate of the hoop seems
to be variable. Sometimes it becomes
solidly silicified, but not much expanded in
breadth, and falls oft" when the two frus-
tules are complete, allowing them to sepa-
rate ; this is the case in Pleurosigma, and
probabl)' in all the allied forms; these
hoops are often to be found in large num-
bers in the settlings of water in which
Diatomacese have been kept a long time.
Perhaps the most remarkable development
of the silicified hoop occiu's in Biddulphia
(PI. 19, fig. 9), Isthmia, and similar forms :

the new half-frustules formed inside the
hoop of these genera slip out from it like
the inner tubes from the outer case of a
telescope. In Melosira (PI. 10. fig. 8) the
hoops appear to keep the new frustules
united together for some time ; and here
there is no overlapping.

The development of the stipes to which
the frustules of many genera are attached,
is obscure ; Cox suggests that in Isth-
mia, a separate internal ceU exists, near
the point at which the frustule is attached,
having the office of secreting the gelatinous
substance of the stipes.

The only mode of reproduction, besides
the division, known certainly to exist in the
Diatomacefe, is that in which conjugation
takes place. This has been observed in a
number of genera, and presents considerable
variation in its details. In Fraqilaria
(PI. 10. fig. 4) and Surirella (PI. 10. fig. 6)
the conjugation takes place between two free
frustiUes lying near together, each of which
opens at the suture and extrudes its con-
tents iu a mass (probably enclosed in the
primordial utricle) ; the masses of contents
coalesce, the whole meanwhUe becoming
involved in a mass of gelatinous substance.
After a while, the body resulting from the
conjugation is seen to assume the form of a
frustide, of larger size than the parents,
which Thwaites, the discoverer, called a
sporangial frustrde. In the majority of
cases, however, as iu Eunotia (PI. 10. fig. 6),
Gomphonema Cocconema, &c., the conjuga-
tion is double, as is the case in Closterium
lineatmn (Con-tugation) ; the contents of
the parent-frustules apparently divide into
two portions (as if for cell-division) before
conjugating ; and then there is a collateral
conjugation of the two pairs, two sporan-
gial frustules being the result. In Melosira
(PL 10. fig. 8) and Orthosira (PI. 10. fig. 9)
the appearances presented seem to indicate
that the conjugation takes place between
two segments of a frustide which have
separated as if for ordinary cell-division ;
but, instead of forming new half-frustules,
have coalesced again and secreted a coat
over the entire surface, thus constituting
one new independent sporangial frustule of
larger size. In Achnanthes and lihabdo-
netna, two sporangial frustules are formed
after the conjugation of the two halves of
one (just-divided) frustule. Probably this
is a case of very early division of the conju-
gation-body. In Melosira (PI. 10. fig. 8)
the conjugation-body has been observed to

DIATOMACE^.

[ 250 ]

DIATOMACILE.

increase by cell-diyisioii, and form a new
filament of far greater diameter than that
to which it owed its birth. The sporangial
fi'ustules of the free forms doubtless increase
by cell-division in the usual way (see Con-
jugation).

In some cases the first product of the
conj ugated mass is a siliceous sheath, inside
which a new frustule is developed, and
finally set free by dehiscence of the sheath
(see Navicula).

A great difficulty meets us here. The
necessary consequence of the conjugation
just described is, that every species in
which it occurs must be represented by two
forms, one small and the other large, be-
tween which a gap exists, over which we
have at present no means of bridging ; ex-
cept by supposing that the two new halves
formed in cell-division need not always be
equal, and that, by a dwindling away through
a succession of steps of this kind, the pro-
geny of the sporangial frustules may be re-
duced to the original size. The size of the
frustides is said also to vary with the depth
of the sea, in marine species. The effect of
all this seems to have been disregarded in
systematic treatises on the Diatomacese.
Some of the book-species appear to produce
other book-species by conjugation; accord-
ing to Focke, Sunrella sjjiendida produces
S. bifrons, a very distinct form ; and it is not
improbable that *S'. splendida is produced by
the conjugation of ^S". Microcora (Focke).
There is great probability, however, that
the observations made by Focke upon the
contents in certain species will lead to the
discovery of another mode of increase —
a reproduction by gonidia, either active
or quiescent, such as occurs in the Desmi-
diacese and the other Confervoids. Indeed
the contents of the cells of Melosira have
been observed to display a motion like
' swarming.' Such spores or gonidia dis-
charged from the large * sporangial ' frus-
tules might reproduce the small form, just
as the young filaments developed from the
zoospores of Cluctophora Sec. are very slen-
der compared with those of full-grown fila-
ments. Focke describes and figures appear-
ances in the contents of the frustules of
Pinmdariu viridis, Sunrella hifrons, and
others, very like what occur occasionally in
the cell-contents of Closten'uni, namely en-
cysted globules (W. 10. fig. 10) resembling
the resting-spores of Volvo.v and the fila-
mentous Confer\-8e (CEdogonium) ; and he
considers that such bodies produced in ■S'.

bifrons may probably reproduce S. Micro-
cora, In some of Thwaites's figures of
conjugating Diatomacete (PI. 10, fig. G),
there are appearances which would lead to
the idea that spores were occasionally pro-
duced in this process.

The principal attraction of the Diatoma-
ceae to microscopists, however, lies at
present in the structure of the siliceous
coats.

Some remarks upon the method of ren-
dering the markings \T.sible have been made
in the Introduction, p. xxviii {lllumina-
tion) ; and upon the cause of their becoming
visible under proper iUumiuation, in the
article Angular Aperture. The grounds
for the belief that most the finer markings
are depressions have also been mentioned
(Introduction, p. xxxix, I.). But the
general view now entertained is, that the
finer markings of the valves are the optical
expressioQ of hemispheres of silica (PI. 15.
fig. 46) ; although it is curious, that neither
Schultze nor Abbe agree with this view.
Yet the formation of the various costae,
xittse, and other siliceous structm'es in the
valves, cannot be referred to any simply
crystalline or crystalloid hemispherical de-
position.

Preparation of the valves, to render them
as distinct as possible, is essential. This
may be effected in two ways: — 1. By inci-
nerating them upon a very thin plate of
mica or platinum foil over the flame of a
spirit-lamp. This is the quickest method ;
but it has the disadvixntages of the valves
often becoming semifused or agglutinated
to each other by the effects of the heat in
the presence of the alkaline salts contained
in all organic matters, especially those which
are of marine origin. 2. Boiling with strong
nitric acid; this is the best method. The
water containing the Diatomaceai is allowed
to settle for twenty-fdur hours, the superna-
tant liquid poured oft", and the deposit dried
in a porcelain dish. Strong nitric acid is
then added, the wliole mixed witli a feather
or glass brush, and poured into a flask or
test-tube and boiled for some time, a portion
being removed occasionally with a narrow
dip-tube to determine when the valves are
perfectly clean. When this is the case di-
stilled water is added to the mixture, and
the whole allowed to settle. The super-
natant liquid is then carefully decanted,
more water added, and the mixture again
allowed to settle, poured off, and tliese ope-
rations repeated until a drop of the liquid

DIATOMACEtE.

[ 251 ]

DIATOMACE^.

containing the valves, when evaporated on a
slide, leaves no film (of calcareous salts) at
the margins of tlio drop. This is a some-
what tedious process ; but it is essential that
it should be tiioroughly carried out. If the
valves be not thoroughly washed, the film
of nitrate of lime remaining upon the slide
will absorb water from the atmosphere, and
the whole will be spoiled.

It has been found advantageous, after the
treatment of the valves with acid and
washing, to shake them up with a mixture
of equal parts of gljxerine and water ; they
then sinlv through the water into the gly-
ceruie, the flocculeut matter being retained
by the water. Thorough washing and de-
cantation will then remove the glycerine
(Neil). Boiling with a small portion of
yellow soap, after the acid treatment, is
highly recommended (H. L. Smith).

The appearance of the valves thus pre-
pared will var}' according to their structure,
and the manner in which they are examined.
In some cases the valves appear colourless,
and the markings perfectly distinct with
the ordinary direct light of the mirror, pro-
vided the power be sufficient (PI. 17. tigs.
2, 29; PI. ol. fig. 1). In others (PI. 15),
the valves appear coloured when viewed by
the ordinary light. But when the mirror is
brought to one side, and the light is thus
thrown upon the object obliquely, one or
two sets of fine parallel black lines are seen
traversing the valves (PI. 1. figs. 17, 18;
PI. 15. figs. 10, 12, 15, &c.). And when an
object-glass of considerable aperture is used,
with the condenser and central stop exactly
centrical (Introduction, p. xix), the lines
are replaced eutirelv or in part by a series of
black dots (PL 1. tig. IG; PI. 15. figs. 39,40,
&c.) ; these, under a high eyepiece, have
distinctly angular forms, sometimes appear-
ing regularly hexagonal (PI. 15. fig. 41).
If the condenser and stop be not exactly
centrical, or the surface of the valve be not
flat, the appearance of dark dots will be
replaced by that of a set of brilliant pearls
(PI. 15. fig. 46), which, as we have stated,
many observers consider to represent little
hemispherical elevations on the surface of
the valves ; or the true form of the dark
dots win be replaced by some other ; thus
hexagonal dots may be made to appear tri-
angular, quadrangular, &c., and those dots
which cannot be conceived to be really
hexagonal (PI. 15. fig. 39) may be made
to appear so.

There can be little doubt that the valves

of all the Diatomaceoe are furnished with
markings, although in some of thorn they
have not yet been detected. In the most
difficultly resolvable of those at present
known, lines only can be rendered evident,
although these probably consist of rows of
dots ; these very difficult valves require the
use of an Amici's prism (Introduction,
p. xxi), Powell's latest modified Gillett's
condenser, the method described in the
Introduction, p. xxx, with immersion-
lenses, or Wenham's reflex-iUuminator
(See also Illu^mination).

We have already stated that we believe
the dots to consist of depressions. In re-
viewing the considerations relating to this
point, we may divide the valves into those
which exhibit the dots by ordinary light,
and those which require oblique light and
the use of stops.

In those visible with ordinary light (PI. 17.
fig. 29 ; PL 51. fig. 1, &c.), the valves are
thinner and weaker at the parts occupied by
the dots, so that the line of fracture corre-
sponds to these parts and the depressions, are
distinctly visible at the edges of the cm'ved
portions of the valves (PL 17. fig. 2 b). In
those requiring the use of oblique light and
stops, the line of fracture also corresponds
to the rows of dots, provided the light be
equally oblique on all sides ; and the same
appearances are presented by the dots in
both cases, beginning with those in which
they are very large (as in Isthmici), to those
of moderate and small size (as in the species
of Coscinodiscus), down to those in which
they are extremelj^ minute (as in Qyrosigma
&c.). Moreover, analogy aftbrds a strong
confirmatory ground; for the Diatomacese
form a very natural family : and if the dots
are depressions in some genera, we might
expect them to be so in the others.

The explanation of the manner in which
oblique light renders the dots visible, has
been given under Angular Aperture,

The method of determining the structure
of the frustules of the Diatomaceaj is the
same as that of microscopic bodies in ge-
neral, and has been laid down in the In-
troduction, p. xxxviii. The presence or
absence of a gelatinous envelope or a stipes
should first be decided. The general form
of the frustides, both in the front and side
view, is next examined, which should be
done while they are immersed in water,
— the frustules being made to roU over by
gently moving the glass cover with the
point of the mounted needle, the eye being

DIATOMAOE^.

[ 252 ]

DTATOMACE^.

kept upon the object, and a somewhat low
power used.

The frustules should then be prepared,
and examined when dry as to their mark-
ings. Perhaps these may be visible by
ordinary light ; if not, the mirror should
be turned on one side as much as possible,
to obtain the eiTects of oblique light. If
lines then become visible, it does not
foUow that the valves are marked with
lined structures such as grooves or ridges,
because the shadows of rows of dots may
become extended into lines imder oblique
illumination in any direction in which the
dots will form a linear series. This point
must, liowever, be decided by examination
with the aid of the condenser, stops, &c.

In using verj^ oblique unilateral light,
spurious rows of parallel lines are often
seen, not only upon the valves of the Dia-
tomacese, but upon objects not possessing a
lined structure, as many crystals &c. These
can only be distinguished from those con-
nected with the presence of dots, by their
not being resolvable into dots, their greater
coarseness, and their variability in number
in a given space under different kinds of
illumination.

If the direction of the lijies changes with
the variation of the position of the valve to
that of the incident light, it may be pretty
surely predicted that the lines are spurious,
and that the condenser and stops will effect
their resolution into dots.

The prepared valves of the Diatomacese
frequently appear coloured when dry, the
colour vanishing when they are moistened.
This colour arises from iridescence, and
not from the presence of pigment or
other colouring - matter (Introduction,
p. xxxiv, 3).

Collection. In collecting the Diatomacefe,
a number of phials (1- to 2-oz.), with wide
mouths and furnished with corks, must be
provided, in which they may bo brought
home. The mouth of the bottle being closed
with the thumb and brought as closely as
possible to masses of them in the water,
on removing the thumb, the water will
enter and carry the Diatomaceae with it
into the bottle. A spoon is frequently of
use in removing layers of them from the
bottom of the water, or from pieces of
woodwork &c. immersed in the water.
Many of them are entangled in the meshes
of Confervaj and other Algae, or on the
submersed stems of the higher plants; these,
if fixed to the stems, can only be removed

with them ; if, however, the masses of
Diatomaceae are merely entangled in the
meshes of their stems, they may be detached
and collected in the " ring-net " (Intro-
duction, p. xxviii),and the pieces of muslin
placed in the bottles. A stick with a loop
of string at the end, is often useful in pro-
curing those which would be otherwise
beyond reach : the neck of the bottle being
engaged in the loop, and the mouth kept
downwards when immersed in the water
until opposite and close to the masses of
Diatomacese, it is then inclined upwards
and filled. On exposing the bottles to the
light for some hours, the Diatomaceae will
collect on the surface of the mud or other
matters, and can then be removed with a
dipping-tube. It is often difficult to free
them from minute particles of sand ; this
may, however, generally be done by dif-
fusing the deposit through distilled water,
allowing the mixture to stand for a short
time, and then pouring off the uppermost
portions; the sand being the heaviest, will
subside first. The deep-sea species may be
obtained by dredging, or by treating' the
alimentary canal of fishes, mollusca, &c.
with strong nitric acid as above dnected.

The Diatomaceae are often found fossil ;
occurring in vast numbers in freshwater
and marine geological deposits, forming
hills, rocks, and various strata ; also in peat-
beds, fossil polishing powders, as tripoli,
berg-mehl, &c, The deposits from Fran-
zenbad, Bilm, Richmond (U.S.). San Fiore
(Tuscany), Bermuda, Lough Morne (Ire-
land), Peruvian guano, kc, are well known
as containing many of the most beautiful
species, and are sold hy the dealers in mi-
croscopic objects and apparatus.

The masses may sometimes be disinte-
grated by placing lumps in a test-tube,
covering them -^-ith Liquor Potasses, boiling
for a short time until the whole breaks up
into a mud, and then instantly pouring it
into a quantity of distilled water, and well
washing.

Preservation. The Diatomaceae may be
preserved either in the dry state, immersed
in balsam, in water, or dilute spirit one to
six (Preservation). For exhibiting the
delicate markings, they should be mounted
in the dry state, placed upon and covered
by the thinnest glass which can be obtained.

The moimted sable-hair or bristle will be
essential in isolating single valves (Intro-
duction, p. xxvi) t'or mounting.

With regard to the systematic arrange-

DIATOMACE.E.

[ 253 ]

DIATOMACE^.

ment of the Diatomacese, it appears impos-
sible at present to divide tliem satisfactorily.
The structure of the frustules of many
o-enera is imperfectly known and described ;
and the supposed species have hitherto been
viewed rather in relation simply to their
differences in form, than to their specific
relations.

The following synopsis, however, will
serve to aid in comparing the principal
genera scattered through the work. In it,
■we have used fr. to denote the frustules as
seen in front view ; v. the valves ; granular
striffi for strife resolvable into dots, con-
tinuous striie being costfe or canaliculi.
The genera included within brackets are
not British, or have been imperfectly de-
scribed.

Analysis of the Tribes and Genera.

* Frustules not enveloped in a yelatinous
mass, nor in gelatinous tubes.

Tribe 1. Striates. Frustules usually trans-
versely striate, but neither vittate nor
areolate.

t Valves tvithout a mediati nodule.

Cohort 1. ErNOTiE^. Fr. arcuate, single
or united into a straight filament.

Epithemia. Fr. single or binate, with
transverse or slightly radiant strife,
some at least continuous ; no terminal
nodules ; freshwater and marine (PI. 16,
tig. 32).

Eunotia. Fr. single or binate ; \. with
slightly radiant granular striae, and
terminal nodules ; freshwater (PL 51 ,
fig. 27).

Himantidium. Fr. as in Eunotia, but
imited into a filament ; strife parallel,
transverse ; freshwater (PI. 16. fig. 36).

lAmphicain^ni. Fossil (PI. 18. figs. 11,

12).]
Cob. 2. Meeidie^, Fr. cuneate, single
or united into a curved or spiral band ;
valves with continuous or granular
strife.

Meridian. Fr. cuneate, united into a
spiral band ; strise continuous ; fresh-
water (PI. 16. fig. 28 ;_ PI. 17. fig. 7).

Eucampiu. Fr. united into an arched
bfind; v. pimctate; marine (PI. 50,

[^Oncosphema. Fr. smgle, cuneate, un-
cinate at the naiTow end ; strise granu-
lar ; freshwater.]

Coh. 3. Feagilarie^. Fr. quadrilateral,
single or united into a filament or
chain ; v. with continuous or granular
striae.
Diatoma. Fr. linear or rectangular, united
by the angles so as to form a zigzag
chain ; strife continuous ; freshwater
and marine (PI. 16. fig. 26).
Asterionella. Fr. adherent by the ad-
jacent angles into a star-like filament ;
V. inflated at one or both ends ; fresh-
water (PI, 18. fig. 14).
Frayilaria. Fr. linear, laiited into a
straight close filament ; striae granular,
faint ; freshwater and marine (PL 16.
fig._3.3).
Denttcida. Fr. linear, single or binate,
rarelv more united ; striae continuous ;
fi-eshVater (PL 16. fig. 25).
Odontidium. As Denticula, but fr. form-
ing a close filament ; freshwater and
marine (PL 17. fig. 14).
Cpnatosira. Frustules imited, margin
undulate in front view ; valves lanceo-
late, punctate, obtuse, without a lon-
gitudinal line; marine (PI. 51. fig. 35).
Plagiogramma. Frustules quadrangular,
free, forming filaments ; valves with
two transverse-median and terminal
costfe, the intervals transversely stri-
ated; marine (PL 51. fig. 41).
Coh. 4, Melosiee^. Fr. cylindrical, disk-
shaped, or globose; v. punctate, or
often with radiate continuous or gra-
nular strife.
Cyclotella. Fr. disk-shaped, mostly soli-
tarv ; v. with radiate marginal striae ;
freshwater (PL 16. figs. 21, 22).
Melosira. Fr. cylindrical or spherical,
united into a filament ; v. punctate, or
with marginal radiate granular striaa ;
freshwater and marine (PL 17. figs. 5, 6),
Podosira. Fr. united in small numbers,
cylindrical or spherical, fixed by a ter-
minal stalli ; V. hemispherical, punc-
tate ; marine (PL 19. fig. 34).
[Mastoyonia. Fr. single ; v. unequal,
angular, mfimmiform, circular at base,
without umbilical processes; angles
radiating ; fossil (PL 18. figs. 23 a, b
24, 25).
PododiscHs. Fr. -single or united, with
a marginal stalk; v. circular, convex
(PL 17. tig. 16). _
Pyxidicida. Fr. single or binate, free
or sessUe ; v. convex ; hoop absent ? ;
fi'eshwater and marine (PL '26. fig. 13).
Stephanodiscus, Fr. single, disk-shaped ;

DIATOMACEyE.

[ 254 ]

DIATOMACE^.

V. circular, equal, punctate or striate,
with a fringe of minute marginal
teeth ; freshwater (PI. 18. figs. 26, 27,
28, 29).
Stephanogonia. Fr. as in Mastogonia,
but ends of valves trimcate, angular,
and spinous ; fossil (Pi. 18. fig. 30).
Hercotheca. Fr. single, tiu'gid laterally ;
V. with marginal fit'ee setse (PI. 18.
fig. 31).
Goniothecium. Fr. single, constricted in
the middle, suddenly attenuate and
truncate at the ends (hence appearing
angular) (PI. 51. fi^s. 18-23).]
Coh. 5. SuEiRELLE^. Fr. single or binate,
quadrilateral, oval, or saddle-shaped,
sometimes constricted in the middle;
V. with transverse or radiating conti-
nuous or granular sti'ite, interrupted in
the middle, or with one or more longi-
tudinal rows of puncta ; often keeled.
Bacillaria. Fr. prismatic, straight, at
tu'st forming a filament ; v. with a me-
dian longitudinal row of puncta ; ma-
rine (PL 16. fig. 14).
Campylodiscus, Fr. single, free, disk-
shaped ; V. curved or twisted (saddle-
shaped) ; freshwater and marine (Pi. 16.
fig. 16 5 PL 25. fig. 18).
Doryphora. Fr. eingle, stalked ; v. lan-
ceolate or elliptical, with transverse
granular striae (PL 16. fig. 20).
Podocystis. Fr. attached, sessile ; v. with
a median line, transverse-continuous
and intermediate granidar striee (PL 61.
fig. 7).
Nitzschm. Fr. free, single, compressed,
usually elongate, straight, ciu'ved or
sigmoid, with a not -median keel, and
one or more longitudinal rows of
puncta ; freshwater and marine (PL 17.
figs. 9-13).
Cymatopleura {Sphinctocystis) . Fr. free,
single, linear, with undulate margins ;
V. oblong or elfiptical, sometimes con-
stricted in the middle; freshwater
(PL 16. figs. 23, 24).
Surirella. Fr. free, single, ovate, ellipti-
cal, oblong, cuneate, or broadh' linear ;
V. with a longitudinal median line or
clear space, margins winged, and with
transverse or slightly radiating con-
tinuous strife ; fresliwater and marine
(PL 17. figs. 21-22).
(Playiodisms.)

Synedra. Fr. prismatic, rectangular, or
curved; at fii'st attached to a gelati-
nous lobed cushion, often becoming

free; v. linear or lanceolate, usually
with a median pseudo-nodule and lon-
gitudinal fine ; freshwater and marine
(PL 17. figs. 23-25).

TryhUonella. Fr. free, linear or elliptical ;
v. plane, with a median line, transverse
striae, and submarginal or obsolete alas ;
freshwater and marine (PL 17. figs.
30-32).

Rhaphone{s= Doryphora without a stalk.
Coh. 6. Ajiphipleure^. Fr. free, single,
straight or shghtly sigmoid ; v. lanceo-
late, or linear-lanceolate, with a median
longitudinal luie.

Amjyhipleura. Char, as above (PL 16.
fig. 7 a, h, c).

Cijlindrotheca (PL 51. fig. 34).

tt Valves with a median nodule,

Coh. 7. CoccoNEiD.^. Fr. straight or bent,
attached by the end or side; valves
elHptical, equilateral.

Cocconeis. Fr. single, compressed, ad-

nate ; v. elliptical, one of them with a

median line (PL 16. figs. 17, 18).

Coh. 8. AcHNANTHE^. Fr. bent, stalked

at one angle or free ; v. -nith a stam-os.

Achnanthes. Fr. compressed, single or
rarely united into a straight filament,
curved, attached by a stalk at one
angle ; uppermost valve with a longi-
tudinal median line, lowermost with
the same, and a stauros or transverse
line ; marine (PL 16. figs. 1-4).

AchunifJiidiiim. Fr. those of Achnanthes,
but free ; freshwater (PL 16. figs. 5, 6).

Cymbosira. Fr. those of Achnanthes, so-
litaiy or binate, stipitate, and attached
end to end ; marine (PL 19. fig. 18).
Coh. 9. Cymbelle^. Fr. straight or
curved, free or stalked at the end ;
V. ineqiulateral, not sigmoid.

Cyvibella. Fr. free, solitary ; v. na-
vicular, with a subcentral and two
terminal nodules, and a submedian
longitudinal fine ; freshwater (PL 51.
fig. 2).

Cocconema. Fr. those o£ Cymbella, but
stalked; freshwater (PL 16. figs. 19,
20).
Coh. 10. GoMPHONEMEJE. Fr. wedge-
shaped, straight, free or stalked; v.
equilateral.

Gomphonema. Fr. single or binate,
wedge-shaped, attached by their ends
to a stalk ; v. with a median line, and
a median and terminal nodules ; fresh-
water (PL 10. fi^'. 34).

DIATOMACE^.

[ 255 ]

DI ATOM ACE /E.

[Sphcnella. Fr. free, solitaiy, wedge-
shaped, involute; freshwater (PL ]9.

fig- 19)-
Sphcnosira. Fr. united into a straight

filament ; v. wedge-shaped, at one end
rounded, suddenly contracted and pro-
duced ; freshwater (PI. 17. fig. 2G).]
Coh. 11. Navicule^. Fr. free, straight ;
V. equilateral, or sometimes sigmoid.

Naviciila. Fr. single, free, straight; v.
oblong, lanceolate or elliptical, with &
median line, a central and two termi-
nal nodules, and transverse or slightly
radiant lines resolvable into dots ;
freshwater, marine, and fossil (PI. 15.
fi^s. 6-9).

{Stigmaphora.)

PleurosH/ma. Fr. those of Kavkida, but
valves sigmoid ; freshwater and marine
(PI. 15. figs. 10-38).

{Toxonidea.)

Pinmdaria. Fr. those of Kavicuht, but
transverse lines continuous and not re-
solvable into dots ; freshwater and ma-
rine (PL 15. figs. 1-5).

Stauroneis. Fr. those of Navicula, but
the median nodule replaced by a stau-
ros; freshwater and marine (PL 15.
figs. 43-45).

Stmirosigma. Fr. those of Staitro7ieis,
with a sigmoid longitudinal line.

Diailesmis. Fr. those of Navicula., united
into a straight filament; freshwater
(PL 16. fig. 27).

Amphiprora. Fr. free, solitary or in
pairs, constricted in the middle ; v.
with a median keel, and a median and
terminal nodules, often twisted ; marine
(PL 16. fig. 8).

(DonMnia.)

Ampihora. Fr. plano-convex, elliptical,
oval or oblong, solitary, free or adnata,
with a marginal line and a nodule or
stauros on the flat side; freshwater
and marine (PL 16. figs. 10, 11).

Perizonium. Frustules navicular, free,
with thickened zones (PL 51. fig. 42.)

Tribe EE. Vitiates. Fr. witb vittae.
t Valves withotct a median nodide.

Cob. 12. LicMOPHOEE^. Fr. cimeate;
vittae arched.
Licmophora. Fr. cuneate, rounded at tbe
broad end, radiating from a branched
stalk ; vittai curved (formed by inflec-
tion of the upper margins of the valves) ;
marine (PL 17. fig, 3),

Podosphenia, Fr. those of Licmophora
but single or in pairs, sessile upon a
thick but little-branched pedicel ; ma-
rine (PL 17. fig. 17).
Rhipidophoi-a. Fr. those of Licmophora,
single or in pairs, upon a branched
stipes ; marine (PL 17. fig. 19).
Climacosphenia. Fr. cuneate, rounded at
the broad end, divided into loculi by
transverse septa or vittae ; marine (PL
25. fig. 9).
Coh, 13. Steiatelle.?:. Fr. tabular or fila-
mentous; vittae straight (not arched).
Striatella. Fr, compoimd, stalked at one
angle ; vittae longitudinal and conti-
nuous ; V. elliptic-lanceolate, not stri-
ated (ord. ilium.) ; marine (PL 17. fig.
20).
Phabdonema. Fr. as in Striatella, but
vittae inten-upted, and v. with trans-
verse granular striae ; marine (PL 17.
fig. 18).
Tetracycliis. Fr. compound, filaments
compressed ; vittae alternate, interrup-
ted ; V. inflated at the middle ; costae
transverse, continuous ; freshwater (PL
17. fig. 28).
Tahellaria. Fr. united into a filament,
svibsequently breaking np into a zigzag
chain ; vittae interrupted, alternate ; v.
inflated at the middle and ends ; fresh-
water (PL 17. fig. 27).
[Pleiirodesmiwm. Fr. tabular, united into
a filament, and with a transverse me-
dian hyaline band ; marine.
Hyalosira. Fr. tabular, fixed by a stalk
at one angle ; vittae alternate, inter-
rupted, bifurcate at the end; marine
(PL 17. fig. 1).
Anaidus. Fr. rectangular, single, com-
pressed, with lateral inflections, giving
the valves a ladder-like appearance ;
marine (PL 18. fig. 7).
Bihlarium. Fr. as in Tetracyclus, but
single ; fossil (PL 50. fig. 39 ; PL 18.
figs. 35-48).
Terpsinoe. Fr. tabular, obsoletely stalked,
subsequently connected by isthmi ;
vittae transverse, short, interrupted
and capitate ; freshwater and marine
(PL 25. fig. 10 ; PL 19. fig. 3.3).
StylobihUi(m. Fi\ compound; v. circu-
lar, sculptured with continuous striae ;
fossil (PL 18, fig. 50).]

tt V- lovth a median apparent (^pseudo-)
nodide.

Grammatophora. Fr. at first adnatej

DLlTOMACiLE.

[ 256 ]

DL^TOMACE^.

afterwards fonning a zigzag chain ;
vittse two, lougitudinal, interrupted at
ends, and more or less figured ; marine
(PL 1. figs. 14, 15).
Diatomella. Fr. quadrangular ; vittse
two, interrupted in the middle and at
each end (PI. 51. fig. 16).

Tribe III. AreoJatce. Valves circular, with
cell-like (areolar) markings, visible by ordi-
nary illumination.

Subtribe 1. Disciformes. Valves ahke, with-
out appendages or processes.

Coh. 14. CosciNODiscE^. Valves circular,

Actinocyclus. Fr. solitary; v. cncular,
undulate, the raised portions appearing
as raj's or bands radiating from the
centre, which is free from markings;
marine and fossil (PI. 25. fig. 17).

Actinoptychus. Fr. as in Actinocyclus,
but radiating internal septa, as well as
rays ; marine and fossil (PI. 25. fig. 16).

Coscinoclisciis. Fr. single ; v. circular,
areolar all over ; marine and fossil
(PI. 51. fig. 1 ; PI. 25. figs. 7, 8).

Arachnoidlscus. Fr. single ; v. circular,
not undulate, with concentric and
radiating lines, and intermediate are-
olaB, absent from the centre (pseudo-
nodule); marine and fossil (PI. 16,
fig. 12),
Asterolampra. Fr, single ; v, circidar,
finely areolar, except in the centre
and on equidistant clear marginal rays
radiating from the centre, which is
traversed by radiating dark lines
(septa) alternating with the marginal
rays ; fossil (PI, 25. fig. 5),

Asterojnphalos. As Asterolampra, but
two of the central dark lines parallel,
and the corresponding marginal ray
obliterated; fossil {PI. 25. fig. 2 ; PI.
18. fig. 15).

Halionyx. Fr. single ; v. circular, with-
out septa, with rays not reaching the
centre, and with intermediate shorter
rays ; between the rays transverse
(concentric P) areolar lines ; fossil (PL
18. fig. 51).

Odontodiscus. Fr. single, lenticular ; v.
covered with puncta (areolae) arranged
in radiating rows or excentrically
curved lines, and with erect marginal
teeth; fossil (PL 18. fig. 52).

Oniphalo2)elta. As Actinoptychus, but
upper part of margin of valves with a

few erect spines; fossil (PI, 18. fig.
53).

Symbolophora. Fr. single, disk-shaped ;
V. with incomplete septa radiating
from the solid angular umbilicus, and
intermediate bundles of radiating lines ;
marine and fossil (PL 25. fig, 6 ; PL 18,
figs. 54,55, 56). _

SystepJumia. Fr. single ; valves circular,
areolar, without rays or septa, with a
crown of spines or an erect membrane
on the outer surface of each valve;
fossil (PL 18. figs. 57, 58).
Coh. 15. AxGULiFER^, Valves angular.

Amphitetras. Fr. at fh'st miited, after-
wards separating into a zigzag chain,
rectangidar ; v. rectangular, the an-
gles often produced ; marine (PL 16.
tig. 9).

Amphipentas. Fr. solitary ; v, penta-
gonal ; fossil (PL 25. fig."^ll).

Lithodesmium. Fr, united into a straight
filament ; v, triangular, one side plane,
the others undulate; marine (PL 17,
fig. 4).

Tribe IV, Appendictdatce . Valves mth
processes or appendages, or with the angles
produced or infiated,

Coh, 16, Et:podisce.5:, Fr, disk-shaped ;
V, circular,

Eiqmdiscus. Fr, single, disk-shaped ;
V, circular, with tubular or horn-like
processes on the surface; freshwater
and marine (PL 16. figs. 30, 31).
\_Auliscus. As Eupodiscus, but processes
obtuse and more solid ; fossil (PL 18,
fig. 60),

Insilella. Fr. single, fusiform ; v. equal,
\n\\\ a median turgid ring between
them=terete Biddulphia; marine.]
Coh. 17. BiDDXJLPHiE^. Fr. flattened ; v.
elliptical or suborbicular.

Biddidphia. Fr. rectangular, more or
less miited into a continuous or zigzag
filament ; the angles inflated or pro-
duced into horns ; v. convex, centre
usuallv spinous ; marine (PL 16, fig.
15 ; PL It), fig. 9).

Isthmia. Fr. rhomboidal or trapezoidal,
cohering by one angle ; angles pro-
duced; marine (PL 17. fig. 2).

Chcetoceros. Fr. compressed ; v. equal,
with a long spine or . filament on each
side; marine (PL 50. fig. 47).

Hhizoselenia, Fr. elongate, subcylindri-
cal, marked with transverse or spiral

DIATOMACE.E.

[ 257 ]

DIATOMACE^.

lines, ends olilique or conical, and with
one or more terniiual bristles ; marine
(PI. 50. fig. 46).

Corinna. Fr. united into seniicironlar
bands; angles produced, s]iinifcrous,
intermediate portion hemispherical,
septate; valves elUpsoid, transversely
bicostate, apicidate at each end.

\_Hemia>ilus. Fr. single, compressed, rec-
tangular, angles produced into tubular
direct processes, those on one valve
longer than those on the other ; fossil
(PI. 25. fig. 3).

St/n'iH/idinm. Fr. single, terete, acu-
minate at one end, two-horued at the
other ; marine (PI. 18. figs. 32, 33).

Periptera. Fr. single, compressed ; v.
unequal, one simply turgid, the other
•svith marginal wings or spines ; fossil
(PL 18. tigs. 66, 67).

Jjicktdia. Fr. single ; v. unequal, one tur-
gid and simple, the other two-horned ;
fossil (PI. 18. figs. 61-65).

Trinacria. Porpeia, Hydrosera (PI. 51.
fig. 40). Solium. Zygoceros. Gly-
phodiscus. Attheya (PI.' 51. fig. 39).]
Coh. 18. Angulat^. Valves angular.

Tricerntinm. Fr. free; v. triangular, each
angle with a minute tooth or horn ;
marine (PI. 17. fig. 29).

\_Syndendrium. Fr. single, subquadran-
gular ; v. unequal, strictly turgid, one
smooth, the other with numerous me-
dian spines or little horns branched at
the ends (PI. 18. fig. 59).]

Eabenhorst makes the Angulatse a sub-
family of Biddulphiese ; comprising the
European genera Triceratium, Trinacria,
and Lithodesmium,

** Friistvles envelojjed in a 7)u/ss of gelatine,
or contained in gelatinous tubes, forming
a frond.

Mastogloia. Frond mammillate ; frus-
tules like Kaviciila, but hoops with
loculi ; freshwater and marine (PI. 51.
fig. 26).

Dickieia. Frond leaf-like ; frustulos like
Navicula or Stata-oneis; marine (PI. 19.
fig. 16).

Berkeleya. Frond rounded at base, fila-
mentous at circumference ; frustules
navicular ; marine (PL 19. fig. 8).

Homaodadia. Frond sparingly divided,
filiform ; frustules like Nitzschia, ma-
rine (PL 19. fig. 15).

Phaphidogloea. Frustules those of Am-

2->hiplci(ra, tufted in railiating gelatinous
filaments (PL 19. lig. 11).

Colletonema. Frond filamentous, fila-
ments not branched ; fr. like Navicula
or Pleurosigma ; freshwater.

Schizonrma. Frond filamentous, branched;
fr. like Navicula .; marine ( PL 19. fig. 12).

Eneyonerna. Frond filamentous, but little
branched; fr. Hke Cymhella; fresh-
water (PL 19. fig. 10).

Syncyrlia. Fr. those of Cymhella, united
in circular bands, immersed in an
amorphous gelatinous frond ; marine
(PL 19. fig. 14).

Frustulia. Fr. those of Navictda, irregu-
larly scattered through an amorphous
gelatinous mass ; freshwater (PL 19.

fig- 17).
Mtcromeyn. Fr. those of Navicula, ar-
ranged in rows, in gelatinous tubes,
or surrounded by fibres, these being
enclosed in a filiform branched frond ;
marine (PL 17. fig. 8).
Many other species are noticed and
figured in this work under the genera,
which have not been described with suffi-
cient brevity to allow of their being tabu-
lated, or are not well established.

BiBL. Ralfs, Ann. N. H. 1843, xi. 447,
xii. 104, 271, 346, 457; Thwaites, Ann.
N. H. 1847, xix. 200, xx. 9, 343 ; 1848, i.
161 ; Smith, Br. Diat. ; Bailey, Silliman^s
Jn. xli.,xlii. ; id. Ann. N. H. 1851, viiL 157,
and Smithson. C'ontrih. 1854 ; Ehrenberg,
Inf. ; id. Berl. Abh. 1839, 1840 ; id. Berl.
Ber. passim ; id. Mikrogeologie ; Brebisson,
Diatomees ; Kiitzing, Bac. and S}). Algarum ;
Pritchard, Inf. (full account of species) ;
Braun, Veijiiny. (Bay Sac. 1853) ; Nageli,
Einzell. Alg. 9: Focke, Physiol. Stuclien,
1853 ; Meneghini, SuW Animalit. kc. (Bay
Soc. 1853) ; Gregory, Diat. Clyde, 1857 ;
Smith (South France) Qii. M. Jn. 1855;
id. (Pyrenees), 1857 ; Greville, Qu. M. Jn.
1859 (Californian), 1865 (Hong Kong),
1 ; H. L. Smith, ^«M. N. H. 1869, iv. 218;
Giunow, Verh. zool.-bot. Geselhch. Wien,
1858, '60, 'Q-2- Qu. M. J. 1877, 166 (Hon-
duras) ; Xylander, Diat. Fennice fossil, addit.
1861 ; Weisse, Schioarz-Erde (Tscherno-
Spnn), 1855 ; Heiberg, Consp. Diat. danic.
1863 (6 pis.) ; Wenham, M. Mic. Jn. ii.
158 (illmnimtting) ; Qu. M. J. 1855, iii. 244 ;
Wallich, Mic. Tr. 1860, 129, viii. 36;
Ann. N. H. 1863, xi. 351 ; M. M. J. 1877,
xvii. 61 ; Schultze, Struct, d. Dint.-Schale,
Verhandl. Naturh. Ver. i^reuss. Bheinl. xx.

DIATOMELLA.

[ 258 ]

DICLADIA.

1 (figs.), f'br. in Qx. M. Jn. 18G3, iii. 120;
Antelmiiielli, Qn. M. Jn. 1868, 254 {repro-
duct.) ; Flfigel, Arch. mikr. An. iv. 472 ;
Macdonald, Ann. N. H. 18G9, iii. 1 ; INIa-
noury, I)iat. 1870; Fritscli & Miiller,
Slailpfur, 1870 {ejcellent photof/raphfi) ;
Donkiu, Br. Diaf. 1871 ; Rabenliorst, Fl.
Alff. i. ; Pfitzer, Hanstein's Bot. Ahh. 1871,
ii. 120; Millarclet and Kraus, Compt.
rendits, Ixvi. 505 ; Aslieusky, Bot. Zcif.
1809, 790; Luders, Bot. Zeit. 1 862 (colourimj
matter) ; Hickie, Schumann''s Diat. formulce,
M. M. J. 1875, xiv, 6 ; Habirshaw, Qdal.
Bint. 1877 ; Lewis, Diat. of United-St. Sea-
board; Schmidt, Atlas {pqs. of all species
8,-c.), 1878; Pettitt, Jn." Mic.'Soc. 1878, i.
237, pis. (Campbell Island ), & Bidl. Soc.
Bot. d. France, xxiii. & xxiv. (Kitton, M.
M. Jn. 1877,xviii. 10 & 05; classn.); Cox,
Amer. Jn. 3Iic. 1878, iii. 100 ; lieurck,
Syn. mat. 1880 (Bekjiqne, pis.) ; Cleve &
Grunow, Diat. Arct. 1880; Laiizi, A71.
Soc. Beh/e (Jn. Mic. Soc. ii. 1879, 38,
</(«//?<«);' Mereschkowsky, Bot. Zeit. 1880,
xxxYiii. 529 (Jn. Mic. Soc. 1881, i. 102) ;
Borscow, Bac. Busslands, 1873 ; Eng-el-
mann, Bot. Zeit. 1879; Ilallier, Diat. 1880
(movement).

DIATOxMELLA, Grev. D. Balfoririana,
Qy.-=Grammat(iphora B.j Smith (PI. 51.
fig. IG) :=Disiphimia aastralis, Ehr.

DIOEL'LA, AVeineck.— A doubtful ge-
nus of Infusoria (Berl. Ber. 1841, 377).

DICIIONE'MA, N. ab Es.— A genus of
Ilymenomycetous Euugi, iuhabitiug tro-
pical America and I'olyuesia.

D. sericeinn consists of a reticulation of
Confervoid filaments, interlaced "with myce-
lium, and at length, like Cora, producing a
distinct hymenium which cracks into
scattered patches. This genus is some-
times called Dictyoncma. Spreading in an
orbicular form, from branches of trees; a
curious microscopic object (,Leightou).
BiBL. Esenb. JS. Acta, xiii. 12.
DI'CHROISM (double colour) is the term
applied to the property possessed by many
doubly refracting crystalline substances, of
exhibiting two colours when light is trans-
mitted through them in difierent positions.
It may be observed under the microscope in
crystals of the tourmaline, the acetate of
copper, the chloride of palladium, and the
oxalate of chromium and potash, or of
chromium and ammonia.

Dichioism depends upon the absorption of
some of the coloured lays of the polarized
light in their passage tlirough the crystal —

this absorption varying with the different
relative positions of the planes of primitive
polarization of these rays to the axis of
double refraction of the crystals, so that the
two pencils formed by double refraction are
dillerently coloured.

In the acetate of copper, the two colours
are deep blue and yellowish green ; in the
chloride of palladium, they are red and
green ; in the oxalate of chromium and
Ijotasli they are blue aud green, and in the
tourmaline they are not always the same;
The variation in colour is entireh^ indepen-
dent of the thickness of the crj'stal.

BiBL. Brewster, Pldl. Tr. 1819, and
Optics, 353 ; Ilerschel, Fncyc. Metr. art.
Liqht, 1064.

biCKIEI'A, Berkeleyand Ealfs.— A ge-
nus of Diatomaceae.

Char. Erustules navicular, irregularly
scattered through a flat undulate frond or
subgelatinous layer, narrowed at the base so
as to appear substipitate.

D. nhoides (PI. 19. fig. 16: a, frond,
nat. size ; b, portion, magnified ; c, prepared
frustule, front view ; d, valve). Stipes very
short, capillary ; frond oblong, irregularly
lobed or crenulate; frustules oblong, ob-
tuse-angled, truncate at the ends: valves
oblong, with a stauros ; length of frond
1 to U" ; of frustules, 1-1000 to 1-720" ;
marine.

Frond very pale purplish white. Recent
frustules with a round colourless spot at
each of the four angles (in the front view).
Found in shallow pools between higb aud
low-water mark.

D. piiinata. Frond irregularly divided,
or laciniate ; v. like Naricida. Marine.

BiBL. Berkeley and Ralls, Ann. JV. H.
1844, xiv. 238, and 1851, viii. 204 ; Kiit-
zing, Bacill. and Sp. Alq. 109; Thwaites,
Ann. N. II. 1848, i. 171 ;" Smith, Brit. Diat.
ii. 166.

DICKSO'NIA, L'lleritier.— A genus of
Dicksonieaj (Polvpodiaceous Ferns), in-
cluding fine arborescent species. All exotic.

DlCKSO'NIEy^E.— A family of Polypo-
diaceous Ferns.

Genera : Onoclea, Hypoderris, Woodsia,
Spheeropteris, Dicksonia, nnd Deparia,

BiBL. Hooker, Syn. Fil. 45.

DICLA'DIA, Ehr.— A genus of Diato-
macefc.

Char. Frustules single ; valves imequal,
one turgid aud simplej the other two-
hovued, the horns sometimes branched.
Marine and fossil.

DICORYNE.

[ 259 ]

DICTYOCHA.

D. caprcolm {V\. 18. figs. 0-3, 04); 7). an-
lennata {P\. 18. fig. (U) ; D. hulbom (V\. 18.
fig. Q2); D. clathrata (PI. 18. fig. (5o).

BiBL. Ehrenb. Berl. Ber. 1844, 73, and
Mikroqeolaqie ; Bailey, SilUm. Jn. 18-30 :
GreA-il'hN Slic. Tr. 18Gb, 56, 98.

DICORYXE, Allra.— A genus of Ily-
droid Polypi, fjira. Atractylidfe.

D. conferta. Ou old shells, Bnccinum, &c.

BiBL. Hincks, Brit. Zooph. 105.

DICOTYLE'DONS.— One of the two
great divisions of the Angiospenuous Flow-
ering: Plants, synonymous with the B.ror/etis
of Decandolie, and opposed to Monocotyle-
dons,— the name being derived from the
condition of the embryo prevailing through-
out the vast majority of plants included in
this assemblage. As in all other natural
groups, instances occur wherein the parti-
cular character from which the name is
derived, the presence of a pair of cotyledons
in the embryo, is absent, as in Orobanche,
&c. (like the Orchidacete and other plants
among the Monocotyledons) ; but in these
cases the plants agree generally with Dico-
tyledons in all the rest of the prominent
characters, such as the structure of stem,
leaves, plan of flower, Szc. See Vegetable
Kingdom, Wood, and Seed.

DICRAN A'CE.^.— A family of Apocar-
pous operculate Mosses, branching by in-
novations, or with the tops of the fertile
branches several times divided. Leaves
lanceolate or subulate, channelled-concave,
with a nerve mostly dilated and flattened,
rarely slender, scarcely cylindrical. The
cells prosenchymatous (often mingled with
parenchymatous), rarely papillose, mostly
empty, often thickened upwards, thereby
rounded or elliptical ; the basilar cells ar-
ranged in a curved manner at the margins
of the leaves, distinctly diverse, paren-
chvmatous, lax, thick, large, flat or with a
more or less thick and patel lif orm front, de-
licate or robust, hyaline, fuscous, brown or
purple, ultimately marcescent, mostly very
conspicuous (alar cells). Capsule oval or
cylindrical, arched or straight, with a su-
bulate operculum. Peristome, if present^
purple, teeth ti'abeculate.

British Genera.

Blindia. Calyptra dimidiate, hood-sha-
ped, peristome wanting or simple, then
of sixteen equidistant, lanceolate, distantly
articulated, smooth, slender teeth, .slightly
trabecuLate within, purple, cartilaginous.
Capsule exannulate.

Dicranum. Calyptra dimidiate. Peri-
stome simple, teeth counate at the base into
a more or less emergent membrane, or equi-
distant and arising below the orifice of the
capsule, split more or less deeply, even in
some cases to the base, into two or rarely
more free arms, purple below, trabeculate-
nodose above (figs. 169 & 170).

Fiff. 169.

Fig. 170.

Dicranum palustre.

Fig. 169. Mouth of the capsule with the peristome
everted. Magnified 40 diameters.

Fig. 170. Portion of the peristome. Magnified 100
diameters.

DI'CRAJsUM, Hedw.— A genus of Di-
cranaceiB (Apocarpous operculate Mosses),
including numerous British sp?cies, very
varied in size and habit ; some, such as D.
scoparium, very common (see Angstroemia
and LEUCOBRYtTM).

BiBL. Wilson, Bryol. Brit.

DICTYD'IUM, Schrad.
— A genus of Myxomycet'^s ;
exceedingly elegant little
plants, gro-s^ang upon rotten
wood. The peridium is ex-
cessively delicate, and the
peculiar capillitium adherent
to it ; so that, when the
spores are expelled, the trans-
parent case appears Hke a
cage, formed of the veins
alone. There are no fila-
ments mingled with the
spores. B. umbilicatum{iig.
171) is a British species ; it
is of a browui-sh-purple co-
lour until the spores are dis- j^'^^~^-^ ^^^^^^
charged, then hyaline ; it is iicatum.
o-reo-arious in its habit of Magn. 25 diam.
growth.

BiBL. Berk. Sook. Br. FI. v. pt. 2. 317;
GreviUe, Sc. Crypt'. Fl. pi. 153; Fries, Si/st.
Mi/c. iii. 164; Schrad. Nov. Gen. 11;
Cmda. Ic. Fimq. v. pi. 3. fig. 36.

DICTY'OCHA, Ehr.— The nature of the
curious bodies, of which the genus Dic-
tyocha consists, is unknown. They consist

DICTYOCYSTA.

[ 260 ]

DICTYOTACE^.

of a single piece ; hence they are not Diato-
macese. This piece is siliceous and loosely
reticulate or stellate. Marine and fossil.

Kiitzing enumerates twenty-nine spe-
cies ; distinguished principally by the num-
ber of external spines and internal are-
olae ; they vary in diameter from l-lloO
to 1-370".

D. yracilis (PI. 2.5. fig. 19, perspective
view; 20, side view ; 21, view from above).

D. fibula (PL 51. fig. 5).

BiBL. Ehrenberg, Berl Ahh. 1838, and
Mikroij. ; Kiitzing, Bacill. and Sp. Aly. 142 ;
Pritchard, Inf. 735.

DIUTYOCYS'TA, Ehr. — A genus of
Peritrichous Infusoria.

Cliar. Free ; enclosed in siliceous per-
forated or pitted loricse, with an anterior
fringe of long cilia, and an inner circle of
uncini ; surface smooth. 6 species. Marine.
(Kent, Itif. 024.)

DICTY'OLAMPRA, Ehr.— A genus of
Diatomaceae.

( 'Jtar. Frustules single ; no internal septa ;
valves equal, cellular (apparently) in the
middle, the smooth margin radiate.

D. Stella (PL 18. fig. 68). The only spe-
cies. Found among Polycystina from Bar-
badoes.

BiBL. Ehr. Ber. Berl Alcad. 1847,54.

DICTYOP'TERIS, PresL— A genus of
Polypodiaceous Ferns, deriving their name
from the reticulated arrangement of the
veins, =^ Pulypodium, pt.

DICTYOPYXIS, Ehr., Grev.— A genus
of marine Diatomacejie.

Char. Frustules areolar, united into short
bands ; valves convex, cupuliform, hoop
ahuent, = Py.ridicula, pt.

D. brevis, Grev.; I), cruciata, Ehr.

BiBL. Grev. Mic. Jn. 1862, 22 (fig.);
'Ehx. Berl. Ahh. 1844; Pritchard, /»/.825;
IJabenhorst, Fl. Ah/, i. 36.

DICTY^OSI'PIION, Grev.— A genus of
Dictyosiphonacete (Fucoid Algae), repre-
sented in Britiiin by a common brauclied
filamentous sea-weed (-D. faniculaceus),
with the frond growing from one to several
feet lonjT, of an olive or rustv-brown co-
lour. The fructilication at present known
consists of ovoid sporanges, imbedded in
the cellular tissue of the branches, lying
lengthways ; tliey open by a pore at the
surface.

BiBL. Harvey, Mar. Aly. 40, pi. 7 D ;
Greville, Air/. Brit. pi. 8 ; Thuret, Ann. Sc.
Nat. 3 ser. xiv. 2-38.

DICTYOSlPIlONA'CE.aE.— A familv

of Eucoideae. Olive-coloured sea-"weeda
with cylindrical branched fronds, the oospo-
ranyes imbedded lengthways in the sub-
stance of the frond, opening by a pore on.
the surface.

British Genera,

Dictyosiphon. Root a minute naked
disk ; frond cylindrical, branched ; oospo-
rattyes scattered irregidai-ly, solitary or in
dot-like sori.

Striaria. Root a minute naked disk ;
frond cylindical, branched ; oosporaiiyes
arranged in transverse lines on the sm-face
of the frond.

BiBL. See the genera.

DICTYOSPn.E'RIUM, Nag.— A genus
of Palmellaceous Algae.

Char. CeUs oblong, green, connected by
filaments, united into free, rounded, plate-
like layers. Freshwater.

2 species. D. Ehrenheryii (PI. 3. fig. 11).

BiBL. Niigeli, Einzell. Aly. 73 ; Archer,
Qu. Mic. Jn. 1866, 127.

DIOTYOSPOR'IUxM, Corda.— A genus
of Torulacei (Coniomycetous Fungi) con-
taining one species, D. ele-
yans (fig. 172), a minute
fungus growing upon oak
which has been stripped of
its bark ; very remarkable
for the reticulated charac-
ter of its spores. Diotyosporium

BiBL. Berk. & Br. Ann. elegans.

Nat. Hist. 2 sef. v. 460 ; Spm-es magnified
„ , T „ . . , _" lOUO diameters.

Uorda, Ico7i. rioiy. ii. pi. 8.
fig. 29.

DICTY'O'TA, Lamx.— A genus of Dic-
tyotaceae (Fucoid Algae), containing one
British species, D. dichotoma (PI. 4.
fig. 2), common between tide-marks, on
rocks, &c. ; remarkable for its dichotomously
divided membranous frond, of olive-green
colour, 3 to 12" long, which, on distinct
individuals, produces three kinds of re-
productive organs, viz. l.tefraspores, divided
crucially, and either scattered or arranged
in sori ; 2. spores grouped in sori and covered
by the common epidermis of the thallus ;
and 3. antheridia, in patches on either face
of the thallus.

BiBL. Harvev. Brit. Ah/. .39, pi. 7A; Phyc.
Brit. pi. 103 ; 'Greville, \ily. Brit. pi. 10 ;
Thuret, Ann. Sc. Nat. 4 ser. iii. 7, pi. 2.

DICTYOTA'CE.E.— A family of Fucoi-
dea3. Olive-coloured inarticulate sea-weeds,
with ItiY^e spores like those of Fucacea?,
superficial, in definite spots or lines (sori),

DICTYOXYrillUM.

[ 2G1 ]

DIDYMOCIIL^NA.

Sori roundish, containing

or scattered. TJoot coated with woolly
fibres. Frond flat.

Many other genera are included in this
faniily by most authors ; but Thui'et has
pointed out that the genera here named
produce spoi-es, while the structures de-
scribed as such in the others are oospo-
ranges. Padixa presents some interesting
points of microscopic structm-e. All the
genera are formed of very regular muri-
form parenchyma.

British Genera.

Haliseris, Frond dichotomous, with a
midrib.

Padina. Frond ribless, fan-shaped, con-
centrically streaked. Sori linear, concen-
tric, bursting through the epidermis.

Zonaria. Frond ribless, lobed, concen-
trically striate
spores and jointed threads

Taonia. Frond ribless, irregularly cleft,
some what fan-shaped. Sori linear, concen-
tric, superficial, alternating with scattered
spores.

Dicfi/ofa. Frond ribless, dichotomous.
Sori roundish, scattered, bursting throug-h
the epidermis, or (on distinct individuals)
scattered spores.

For other genera often included here, see
Spoj80ch:n-ace.^e,Puxctariace.^,Dictyo-
siPHOXACE^, and Cutleriace^e.

BiBL. See the genera.

DICTYOXYPH'IUM, Hooker.— A ge-
nus of Lindsayeoe (Polypodiaceous Ferns).
Exotic.

DICYE'MA, KolL— A genus of Infuso-
ria (?), allied to Opalina.

D. Miilleri is found in the kidneys &c. of
Cephalopoda.

BiBL. Erdl, Erichs. Arch. 1843, 162;
Kolliker, Wllrzhurg Ber. 1849 ; Clap, and
Lachm. Infax. ii. 201.

DIDER'MA, Pers.— A genus of Myxo-
mycetes, consisting of minute epiphytic
plants of tolerably persistent structure
(fig. 173). The peculiar cha-
racter resides in the double Fig. 173.
layer of the peridium, the
outer being smooth and crust-
like, fragile and dehiscent,
while the inner is very deli-
cate and evanescent. The spe-
cies vary in habit, being either
stipitate with the stalk more dotum.
{Leangium, Uk.) or less {Leo- yi^^i^^^2o
carpus, Lk.) distinct in dif- diams.
ferent cases, and sessile. A

Diderma lepi-

dozen species are recorded as British, of
whicli the sessile D. g/ohosum, and the ob-
scurely stalked D. i-ernicosnm, appear the
commonest.

BiBL. Berk. Hook. Br if. Fl. v. pt. 2.
310 ; Ann. N. II. i. 257 ; (Jrgpt. Bot. 337 ;
Fries, Syst. Myc. iii. 96 ; Summa Veg. 4o0 ;
Greville, So. Cnjpt. Fl. pis. 3, 122 & 132 ;
Corda, Ic. Funq.

DIDIMTUM, Stein.— A genus of Peri-
trichous Infusoria.

Char. Free, ovate, or subcylindrical, with
an anterior and posterior ciliary wreath;
snout-like in front.

B. nasutiim. Pond- water ; length 1-300",
(Kent, Inf. 638.)

DIDYM'lUM, Schrad. — A genus of
Myxomycetes, consisting of minute plants
growing upon leaves, bark, rotten wood,
&c. (fig. 174), distinguished by its double
peridium, of which, however, the inner
membranous layer is the true case
(bursting irregularly), while the Fig. 174.
outer forms a kind of bark, which
breaks up into little furfuraceous
scales or mealy down. Filaments
exist twining among the spores
adherent to the peridium. Six-
teen species are recorded as Bri-
tish, several of which are not
uncommon. They vary in habit,
like the Didermce, being either
stalked, sessile, or adnate to their
support. Z). farinaceum is figtu'ed
Sowerby as Trichia sphcerocephula.

BiBL. Berk. Hooh. Br. Fl. v. pt. 2, 312 ;
Ann. N. H. i. 257, 1850, v. 365, xiii. 459 ;
Crypt. Botany, 337 ; Fries, Syst. Myc. iii.
113 ; Sumtna Vec/. 451 ; Sowerbv, Fungi,
pis. 12, 240, 412; Corda, Ic.Fung.

DIDYMOCHL.E'NA, Desv.— A genus

Fig. 175.

Fig. 176.

Liidjaiiium

hemispha;-

rieum.

Magnified
20 diams.

^J

Didymoehlfena ainuosa.
Fig. 175. A Borus, from above. Magn. 20 diams.
Fig. 176. Transverse vertical section of ditto.

DIDYMOCLADON.

C 262 ]

DIDYMOSPORIUM.

of Aspidiepe (Polypodiaceous Ferns), with a
curious elliptical" indusium opening on each
side (fifrs. 175 & 176). Exotic.

DIDYMO'CLADON, Ralfs.— A genus
of Desmidiaceoe.

Chnr. Cells single, constricted at the
middle, end view tri- or quadrangular ; each
angle with two processes, one lateral and
in the front view nearly parallel with the
corresponding one of the other segment,
the other superior and divergent.

The two processes distinguish this genus
from S/aiirasfrum.

I), fwcu/ems (PL 14. fig. 32, front view 5
fig. 56, end view).

a, end view triangular.
j8, end view quadrangular.
Length, including processes, 1-330",
BiBL. Ilalfs, Brit. Desmid. 144.
DIDYMOIIE'LIX, Gritfith.— Agemisof
Oscillatoriacese (Confervoid Algae), with the
threads consisting of pairs of microscopic,
interlacing, ferruginous, spiral filaments;
probably surrounded by gelatine.

It seems to have no relation with Gcd-
lionella as formerly supposed.
Found in ferruginous bog-water.
The structure of the compound filaments
of which this beautiful and curious organism
consists requires great care to elicit, both
on account of their minute size and their
peculiar form. The breadth of the filaments
is from l-oOOO to 1-30,000", the average
1-10,000 to 1-20,000". Filaments imbued
with peroxide of iron, containing no silica,
or not more than a trace, such as is naturally
invariably associated with the peroxide.
"With hydrosulpliuret of ammonia, they be-
come black. Acted upon slo^^■ly with di-
lute muriatic acid, the colour gradually
Tanishcs, a very transparent colourless cast
of the original being left. If the compound
filaments are macerated for some time in
distilled water, the filaments Avill separate
(PI. 1. fig- 10(/). Under a ;|-inch object-
glass, the filaments present the appearance
represented in PI. 1 . fig. 10 a. When a
higher power is used, they appear as in fig.
10 h, which represents them as seen when
too much liquid is contained between the
slide and the cover, or when llie proper
correction is not made for the thicknpss of
the glass cover and of tlie liquid, or when
lying edgewise. When lying flat upon the
slide, and tlie correction is perfect, they ap-
pear as in PL 1. fig. 10 c.

In the natural state, a quantity of yel-
lowish-brown gelatinous mutter is always

found in the water containing the filaments.
In the ferruginous gelatine are found some
fibres of a very minute Nostochaceous
plant, probably Anabaina suhtilissima,
Kiitz. Didymohelix is by no means com-
mon, even in waters which contain a very
copious ferruginous deposit. It is found in
ditches in Dumfriesshire, 10 or 12 inches in
thickness.

It may be preserved either in the dry
state, in chloride of calcium, or in balsam.

We have enumerated this as a test-object
for the general excellence of a high-power
object-glass, also of the observer's manage-
ment of the microscope. See Test-Objects,
BiBL. Griffith, Ann. Nat. H. 1853, xii,
438; Davies, 31. M. Jn. 1877, xvii. 54.

DIDYMO'PEIUiM, Kutz.— A genus of
Desmidiaceae.

Char. Cells with a bidentate or bicrenate
process on each side, united into an elon-
gated, fragile, cylindrical, and regularly
twisted filament. (Sheath either present,
wanting, or indistinct.)

Diflers from Desmidium in having only
two processes, and not being angular, and
in the number of rays of the endochrome
in the side view not depending upon the
number of angles.

D. Borreri (?].!. fig. 11). Joints in-
flated, barrel-shaped, longer than broad :
side view circular ; angles bicrenate. (Sheath
wanting or indistinct.)

The delicate longitudinal lines were pro-
prosed by Jeuner as a test-object for the
power of the microscope; they are best seen
i]i the empty cells when dried. Breadth
of fllament 1-1030".

D. Grevdlii (PL 14. fig. 5 ; fig. 6, side
view). Joints broader than long, with a
thickened border at their junction ; side
view broadly elliptic ; angles bidentate.
(Sheath distinct.) Breadth of filament
1-470".

BiBL. Ralfs, Brit. Desmid. p. 55,
DIDYMOSPO'PJUM, Nees.— A genus
of iNIelanconiei (Stylosporous Fungi), grow-
ing upon shoots of trees. The only British
species, D. profusum, Grev., has very mi-
nute, oblong, uniseptate spores, at first glued
together like a depressed conical nucleus,
bi>neath the epidermis, afterwards bursting
through and becoming free. I), elevatum,
Lk. = Mclaneonium bico/oi; Nees.

Greville's plant, however, has not truly
uni,-.(>plate spores, and is rather a Melanco-
iiiiim, re*"erred as a conidiiferous form by
Tulasne to yJelanconii{m stilbostoma.

DIFFLUGIA.

[ 263 ]

DLMORPIIINA.

BiBL. Berk. Kooh. Brit. Fl,r. v. pt. 2.
357 ; Ann. N. II. 1840, vi. 438 ; Grcville,
8c. Cnipt. i^/.pl. :?12.ti<r. 1 (as Stilhosjjora);
Till. Carp. ii. li'O.

DIFFLU'GIA, Leclerc— A genus of
Rhizopoda, of the family Arcellina.

Char. Contained in a spherical or oblong,
urceolate, incrusted carapace, from the an-
terior extremity of which are emitted
variable numerous or niultifid tentacular
expansions. Freshwater.

The carapace is membranous, incrusted
with minute grains of sand (and carbonate
of lime ?) ; in some it is covered with de-
pre>-sions or tubercles; these form the genus
EiKjhjpha, D. D. Enchebjs forms gem-
mie, and also resolves itself into four
" spores."

Species verv numerous.

D. proteiformis, E. (PI. 30. fig. 39.) Ca-
rapace oval or almost spherical, covered
with minute grains of sancl; length 1-240".

D. oblo)if/a, E. {D. i/lobulosa (:-'), D.).
Carapace oval, oblong, or rounded, smooth,
brownish; length 1-200".

BiBL. Leclerc, Mem. Muricum, ii. 474 ;
Ehr. Inf. 130 ; and Berl. Ber. 1840 ; Du-
jardin, //i/. 248; Schluinberger, Ann. Sc.
Nat. 184o, iii. 254; Schneider, Ann. N. II.
1854, xiv. 332 ; Clap. & Lachm. Inf. 447 ;
Lauix, Qu. Mic. Jn. 1865, 285 ; Tatem, M.
M. /. 1870, iv. 313; Archer, Qu. M. J.
1877, xvii. 115.

DIGLEXA, Ehr.— A genus of Rotatoria,
of the family Hydatinaea.

Char. Eyes two, frontal ; foot forked.

There are no other appeudages than the
foot and the rotatory organ.

Nine species.

D. lacmtris (PI. 43. figs. 21, 22). Body
oval, transparent, trimcate in front ; foot
suddenly attenuate, somewhat more than
l-4th of the body in length ; toes l-3rd
part of the foot in lenoth ; freshwater ;
length 1-70".

BiBL. Ehr. Infus. 441 ; Gosse, Ann. N.
H. 1851, viii. 200.

DILEP'TUS, Duj.— A genus of Infuso-
ria, fam, Trichodina.

Char. Body fusiform, prolonged ante-
ri(jrly in the form of a swan's neck, ^^dth a
lateral mouth at the base of the prolonga-
tion ; entire surface covered with vibratile
cilia, which are more distinct in front and
near the mouth.

D. folium, D. (PI. 30. fig. 40). Body
very flexible, in the form of a lanceolate
leaf, narrowed in front ; with nodular, reti-

culated, irregular ribs j freshwater; length
1-1()0 to 1-120".

I), anscr (Amphileptus anser, E.).

D. margaritifer {Amphile2)tus marr/., E.).

Dujardin separates these species from the
genus Amj)hil('pfus, on account of their not
possessing a reticulated integument, and
their undergoing diilluence. CI. & Lachm.
unite them with A?nphileptu.ji,

BiBL. Duj. Infus. 404.

DILOPHOS'PHORA, Desm.— A genus
of Sphferonemei (Stylosporous Fungi), con-
sisting of »S/iA<re/7a-like plants (without asci),
growing upon the leaf-sheaths and glumes

Fig. 177.

Dilophosphora graminis.
Spores. Magnified 800 diams.

of grasses ; remarkable for the curiously ap-
pendaged spores (fig. 177).

I), graminis, Desm. = Sjyhrvria Ahpecun,
Fries. Sometimes very destructive to wheat-
crops in the south of England.

BiBL. Desmazieres, Ann. Sc. Nat. 2 ser.
xiv. p. 4. pi. 1. fig. 2.

DIMASTIGOAU'LAX, Dies. = Peridi-
niutn cornutum, Ehr., Ceratium c, Clapa,-
rede & Lachmanu. (Kent, Inf. 462. )

DBIEREGRAM'MA, Pritch.— A genus
of Diatomaceae.

Char. Frustules quadrangular, two or
more together; valves (undulate, Rab.)with
transverse costfe interrupted by a smooth
longitudinal line.

Several species.

BiBL. Pritchard, Inf. 123 ; Grun. Wien.
Verh. 1862; Gregory, D/«;^. (/ Clgde, 22;
Rabenhorst, F/or. Alg. i. 123.

DI'310NAS, Kent.— A genus of Flagel-
late Infusoria.

Char. Free, ovate or p^i'iform ; flagella
2, equal ; mouth very dilatable.

Two species : in infusions, fresh and salt ;
hav. (Kent, Inf 421.)

DIMORPHI'NA, D'Orb. — A hyaline
Foraminifer, in which the early chambers
have the alternate growth of a Polgmor-
pliina, and the later ones the linear arrange-
ment of a Nodosaria. D. tuberosa, D'Orb.

DIMORPHOCOCCCS.

[ 264 ]

DIXOPIIYSIS.

Modele no. 60, is the type of this dimor-
phous Poh/inur])lnna. Fossil and recent.

BiBL. Parker and Jones, Ann. N. H. ser.
3. xvi. 28; D'Orb. For. Foss. Vien. 2l>l.

DIMORPIIOCOCCUS, Braun.— A ge-
nus of Palmellaceous Algse ; consisting of
free botryoidal substipitate groups of ovate
or lunate green cells, 4 in each.

D. lunatus (PI. 51. fig. 43). In pools ;
Germany.

BiBL. Braun, Ah/. Unicell. 44.

DINEMASPO'RIUM, Lev.— A genus of
Sphoeronemei (Stylosporous Fungi), con-
sisting of minute plants forming spots upon
the leaves of grasses. F>. gramineum, Lev.,
the only British species, =
Excijmla grammis, Berk. Br.
Fungi, No. 328, and Frc.
gram., Corda. It has a scat-
tered conceptacle, closed at
first, and subsequently widely
opened, forming a disk CO vered
with white spores of a peculiar
form, abruptly produced into
filaments at each end (%.
178).

BiBL. Berk, and Broome,
Ann. N. H. 2 ser. v. 456 ;
Leveille, Ann. Sc. Nat. 3 ser.

v. 274; (u OV^a,, Icon. Fung. \il. Dinemasporium
pi. 5. fig. 79. gramineum.

DI^ EMOU 'RA, Latr.— A eoo diams^
genus of Crustacea, belonging
to the order Siphouostoma and family Pan-
daridse.

Char. Lamellar elytriform appendages
covering the thorax, only one pair. First
three pairs of legs setiferou's ; the posterior
foliaceous and membranous.

D. alata and D. Lammc have both been
found upon the Beaumaris Shark {Lamna
mo7iensis).

BiBL. Baird, JBrit. Entomostr. 282.

DINENYMTHA, Leidy.— A genus of
Holotrichous Ir.fusoria.

Free, elongate, flexible, ciliated all
over.

D. gracilis, in the intestines of white ants.
(Kent, Inf. 555.)

DINOBRYl'NA, Ehr.— A family of
Flagellate Infusoria.

Char. Bodies variable in form, with Iwo
flagella, one short, one long ; contained in
urceolate capsules, which are either single,
or aggregated into a branched zoary
from the new capsules remaining adlierent
by their bases to the summits or the bases
of the preceding : the result of multiplica-

tion by gemmation ; freshwater. (Astasiaea
with a carapace.)

1\a'o genera, Dinohryon and Fpipg.vis.

In Dinohryon an interior red eye-spot is
present, but not in Epipyxis. In the former
a flagelliform filament is present ; this is
sometimes met with in the latter, but not
con.-tantlv.

BiBL. Ehr. In-f. 122; Duj. Inf. 320.

DINOB'RYON, Ehr.— A genus of In-
fusoria, of the family Binobryina.

Char. Carapaces urceolate, united in the
form of a branched polvpidom.

D. serialaria, E. {n. 30. fig. 41). Cara-
paces sessile or subsessile, slightly constric-
ted near the somewhat expanded and ex-
cised end ; length of zoary 1-144 to 1-120",
of bodies 1-570".

Hermann and Archer point out that the
bodies become encysted at the mouth of the
capsules, forming Chlamydomonas - like
organisms.

Bodies yellow or green, with a red eye-
spot in front.

D. sociale, E. Carapace conical, truncate.

D. gracile, E. Carapace slightly con-
stricted in the middle.

D. petiolatum, D. (PI. 30. fig. 42). Ca-
rapaces with long stalks, bodies green ;
length of the polvpidom 1-100", of a cara-
pace 1-1420".

BiBL. Ehr. Infus. 124, and Beri. Ber.
1840, 109; Duj. Inf 321; Archer, Qu. Mic.
Jn. 186G, V23 ;' Kent, Inf. 409.

DINO'CIIARIS, Ehr.— A genus of Ro-
tatoria, of the family Euchlanidota.

Char. A single cervical eye; foot forked;
carapace closed beneath, and without teeth
at the ends.

Jaws ^v^th one (or two.^) teeth each.
Aq uatic. Two horns at the base of the foot.

D. tetractis (PL 43. fig. 23; fig. 24, teeth).
Carapace acutely triangular, two horns at the
base ofthe foot, and two toes; lengthl-120".

Two other species.

BiBL. Ehr. Infus. 471.

DINO'PIIYSiS, Ehr. -A genus of Fla-
gellate Infusoria, of the family Peridina3a ;
marine.

Char. Free, single; carapace membranous,
urceolate, with a transverse ciliated furrow,
and a median plicate crest ; no eye-spot.

Form, that of Vaginicola; nature, that of
Peridmium. The transverse furrow is close
tu the truncated anterior end ; and from this
furrow there extends down thebody a folded
crest or fringe, like that of Sientor, except
that it is a part of the (jarnpace. A crown of

DIOPIIEYS.

[ 2Go ]

DiPLOnONTUS.

cilia exists around the neck, and a longer
liagelliform filament. Carapace punctate.

D. norioeffica ; length 1-4:20".

Eleven species, Kent.

The species are found in sea-water with
luminous animals ; probahly themselves
luminous.

BiBL. Ehr. JBerl. Ahh. 1839, 125, 151 ;
Kent, Inf. 458.

DIOTHKYS, Duj.— A genus of Infuso-
ria, of the family Plossconina.

Char. Body of irregular discoidal form,
thick, concave above and convex beneath,
with five large vibratile cilia at the ante-
rior, and four or five very long geniculate
setje near the posterior end. Marine.

D. mariiia (PL 30. fig. 43 : a, under view ;
b, side view). Body oval, with a longitudi-
nal excavation; length 1-580".

BiBL. Duj. Inf. 445 5 Clap. & Lachm.
I?if. 400.

DIORITE. See Rocks.

13IOSAC'0US,Boeck.— AgenusofCope-
poda (Entomostraca.)

One species ; marine.

BiBL. Brady, Copep., Ray Soc. ii. 68.

DIPHA'SIA, Agassiz. — A genus of ma-
rine Hydroid Zoophytes, family Sertula-
riidfe = <S'('/-(';</rt/'m, pt. ; comprising the spe-
cies with the ovigerous vesicles cleft at
the margin. 7 species.

BiBL. Hincks, Brit. Zooph. p. 244.

DIPHYSCIA'CE.E.— A family of oper-
culate Acrocarpous Mosses, having a cap-
sule of very curious structure. The leaves
are of two kinds, the cauline tongue-shaped,
composed of perfectly Pottioid, densely
hexagonal, parenchymatous cells filled Avith
chlorophyll ; the perichietial leaves much
protruded, exceeding the cauline, composed
of cells ultimately destitute of chlorophyll,
therefore of looser texture. Capsule very
large, oblique, gibbous, somewhat like that
of Buxhaumia. Inflorescence monoeciuus.
British genus :

DIPHYS'CIUM, Mohr.— Calyptra coni-
cal, covering the operculum. Peristome
simple, internal, resembling that of Bux-
haumia, surrounded at the base by a large
multiplex, soluble annulus.

BiBL. Wilson, Bryol. Brit. 200 ; Berke-
lev, Ilandb. 214.

"DIPLA'SIUM, Presl.— A genus of As-
pleniefe (Polvpodioid Ferns). Exotic.

DI'PLAX', Gosse.— A genus of Rotato-
ria, of the family Euchlanidota.

Char. Those of Salpina, except that the
eye is wanting, and the cai-apace (which, as

in that genus, is cleft down the back) is
destitute of spines both in front and behind ;
foot and toes long and slender.

Forms a connecting link between Salpina
and Dinocharis.

D. vomp>ressa. Carapace in side view
forming nearly a parallelogram, greatly com-
pressed ; length 1-170" ; freshwater.

I), trigona. Carapace trilateral ; surface
delicately punctured ; length 1-160" ; fresh-
water.

BiBL. Gosse, Ann. N. H. 1851, viii. 201.

DIPLOCO'LON, Nag.— A doubtfid ge-
nus of Scytonemaceous Algse.

D. Heppii. On calcareous rocks; Ger-
many.

BiBL. Nageli, Nov. Act. 1857 ; Raben-
horst, Fl. Alq. ii. 246 (fig.).

DIPLO'UiA, Fr.— A genus of Sphterone-
mei (Stylosporous Fungi), usually growing
upon dead twigs &c., bursting through the
epidermis. Numerous species have been
described as British by Mr. Berkeley ; but
the resemblance of many to various SphcericB
is remarked by him, and Tulasne states that
they are only stylosporous forms of species
belonging to that genus or its allies.

BiBL. Berk. Ann. N. H. vi. 365, pi. 11;
1850, V. 371 ; xiii. p. 459 ; Hook .Jn. Bot.
iii. 320, V. 40; Leveille, Ann. Sc. Nat.

3 ser. V. 290 ; Tulasne, ibid. xx. 136 ; ibid.

4 ser. V. 115.

DIPLODON'TUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Hydrachnea.

Char. Mandibles terminated by a straight,
acute, and immoveable tooth, to which is
opposed a moveable hook or claw ; palpi
shortish, with the fourth joint longest and
terminated by a point as long as the fifth
joint; coxfe not very broad, in four separate
groups, the posterior of which are semi-
divergent ; a bivalve, granulated, heart-
shaped genital plate, the apex directed for-
wards.

D. scapularis (PI. 6. fig. 80 : fig. a, labium
with a palp, under view ; 6, a separate
mandible more magnified than a). Eyes
very small, but projecting, wide apart, placed
at the anterior rounded angles of the body,
blackish and reniform, arising from the
fusion of two stemmata. Anterior half of
the body black, speckled with a few red
spots ; posterior half scarlet, but divided by
a median longitudinal black band. Length
of female 1-10"; male l-3rd or l-4th the
size of the female.

D. Jilipes. Palpi much curved down-

DIPLOMASTIX.

266 ]

DISCOMYCETES.

wards, but little visible fi-om above. Body
elliptical, depressed, bright red, sometimes
marbled with dark brown spots, from the
digestive organs being visible through the
integument. Eyes four, at tlie very anterior
margin, so best seen from beneath. Inte-
gument finelv granular, without hairs. Legs
red. Length 1-25".

D. mendax. Two clear longitudinal rays
at the fore part of the body.

BiBL. Duges, Ann. Sc. Nat. 2 ser. i. 148.

DIPLOMAS'TLY, Kent.— A genus of
Flagellate Infusoria.

Char. Ovate, free, colourless, variable ;
flagella 2, one vibratile, the other trailing ;
mouth distinct.

Three species ; salt and fresh water.

BiBL. Kent, Inf. 431.

DIPLO'MITA," Kent.— A genus of Fla-
gellate Infusoria.

Char. Solitary, ovate, attached by a re-
tractile filament to the base of a stalked
horny lorica, flagella two, alike ; eye-spot
sometimes present ; no mouth.

D. socialis. Brownish, length 1-lGOO" ;
pond-water.

BiBL. Kent, Inf. 2S9.

DIPLONE'IS,"Ehr. = Aw?«<Z« with the
valves constricted in the middle.

DIPLOZO'ON, Nordm.~A genus of
Treraatode Entozoa.

Cliar. Body of individuals soft, elongated
and flattened; united in pairs by tlieir fusion
near the middle, thus resembling an X ;
each body terminated posteriorly by a trans-
verse, oval, or almost quadrilateral expan-
sion, furnished with four suctorial disks.
Mouth terminal, anterior, accompanied by
two oblong suctorial disks.

D.paracloxum, the double animal. Found
upon the giUs of freshwater fishes, as the
carp, the roach, the bream, &c. Length
l-<) to 1-5", or twice this length.

The separate individuals {Diporpa, Du-
jardin) are smaller than those in a state of
conjugation (length 1-100 to 1-45"), and
contain no trace of reproductive organs.
Ova formed in each individual after the
conjugation; they ai'e yellow, with the
shell narrowed and prolonged into a fila-
mentous spiriil or coil.

BiBL. Nordmaun, Mi7>:r. Beit. 1832, i.
50; Ann. Sc. Nat. 1833, xxx. ; Ehrenberg,
Wiefjmann's Archiv, 1835, ii. 128; Mayer,
An. (l.Entoz. 23 ; Sicbold, Siel). u. Koll. Zeits.
iii. 02; Vogt, MiiUcr's Archiv, 1841,33.

DIPODINA, Ehr.— A genus of Rotato-
ria. Differs from Notommata by a particu-

lar constriction of its tarsal nippers or toes.
At Wismar. (Pritchard, Inf. 713.)

DIPOR'ULA, Hincks.— A genus of
Cheilostomatous Polyzoa.

D. verrucosa; Cornwall. (Hincks,Po/(/soa,
220.)

DIP'TERA.— The seventh order of Ix-
SECTs, containing the " flies," &c.

DIRI'NA, Fr. — A genus of Lichenaceous
Lichens, tribe Lecanorei.

D. ceratonice (fig. 26, p. 65).

D. repanda. Occurs in Jersey.

BiBL. Leiahton, Lich. Fl. G. B. p. 226.

DISCELIA'CE.E.— A family of opercu-
late Acrocarpous Mosses, of gregarious ha-
bit, very dwarf and stemless, arising from a
green prothallium spreading on the ground.
The sheathing leaves are appressed, obluug,
acuminate and nerveless, composed of cells
lax at the base and apex, rhomboidally pa-
renchymatous, destitute of chlorophyll,
fuscescent and empty. Capsule subglobose
and inclined, with a short collum, annu ate
and long-stalked. The antheridial and a--
chegonial flowers are upon the same runner
of the prothallium. British genus:

DISCELIUM, Brid.— Calyptra longish,
very narrow, split almost to the summit,
wider in the middle, with the margin invo-
lute on each side at the base. Peristome
simple, of sixteen lanceolate teeth, tissile
in the middle, trabecidate, striate, cartila-
ginous, reddish or orange.

BiBL. Wilson, Bryol. Brit. 286 ; Berke-
ley, Ilandb. 107.

'DISCEL'LA, Berk, and Br.— A genus of
Splneronemei (Stylosporous Fungi), forming
scattered, disk-like, dark spots upon twigs ;
at first covered by the epidermis, which
afterwards splits and separates. Five spe-
cies are described, occurring on the wiUow,
lime, plane, and elder.

BiBL. Berk, and Broome, Ann. N. II.
2 ser. V. 370, pi. 12. fig. 8 ; Berkeley, Outl
322.

DISCOCEPH'ALUS, E.— A genus of
Infusoria, of the tauiily Euplota.
• C]>ar. Head distinct from the body ; hooks
present, but neither stvles nor teeth.

D. rotaiorius (PL 30. fig. 44). Hyaline,
flat, rounded at each end ; head narrower
than tlie body; length 1-380". Red Sea.
Imperfectly examined.

BiBL. Ehr. Infu.-. p. 375.

DISCOMYCETES.— The name of one
of the lamilies of Fungi under Fries's clas-
sification, including the Helvellacei and
Phacidiacei of th(^ Ascojiycetes.

DISCOPLEA.

[ 267 ]

DISTIOIIIUM.

DISCOPLE'A, Ehr.— A genus of Diato-
macoa\ not now retained, the species being
refenvdto tlie genera Ct/clofc/laiind Coacino-
rf/mw. Ehr. Jier. Ber'l. Ak. 1844, p. 197.

prSCORBT'NA, Parker and Jones.— One
of the Rofcdinco, having a turbiuoid spire,
■with vesicuhir chambers, opening one into
anotlier by slit-like apertures, which are
usually tented over by a succession of um-
bilical Haps, forming a star-like ornament
(see AsTKRiGERiN.vK The shell is usually
coarsely, sometimes finely, and occasionally
partially porous. Fossil and recent. D.
rosacea\V\. :34. fig. 7 a, b) is a neat variety
of D. turbo.

BiBL. Carpenter, Introd. Foram. 203.
DISOO'SIA, Libert.— A genus of Sphre-
ronomei (Stylosporous Fungi), probably re-
lated to some of the Spha-rice, as stylospo-
rous forms. The species have been described
under various names ; and the genus Ph/i/c-
tid'mm of Notaris is synonymous with it.
The British species recorded seem to have
been greatly confused by ditlerent writers ;
for Discosia alnea, Libert, found on the
leaves of alder and beech, = »S';j/w^/-/« arfo-
creas, Tode. Xi/hima f(igineum,Ve\'$., Vhlijc-
tidium nitidinn, Wallr., Ph. clypoatum, No-
taris, and, from its name, we conclude also
Dothidea alnea, Pers. of Hook. Brit Flor.,
with its synonyms. Fries, in his Smnma
Veget., gives D. artocreas, alnea, and chj-
peata as three distinct species.

BiBi.. Leveille, Ann. Sc. Nat. .3 ser. v.
286 ; Fries, Sum. Veget. 423 ; Fresenius,
Beitr. z. Mycol. Heft i. 66, pi. 8 ; De No-
taris, Mem. Accad. Torino, 1849, 2 ser. x. ;
Berk., Hooh. Br. Fl. 278, 288.

DLSCOSIRA, Ptab.— A genus of Diato-
macese.

Char. Frustules disk-shaped, concate-
nate ; valves nearly plane, with curved
costfe ; margin denticulate ; centre deli-
cately punctate.
D. sulcata. Italy.

BiBL. Rabenhorst, Flor. Alg. i. p. 36.
DISEL'MIS, Duj. = Chl.vimidomoxas,
Ehr. {Chi. pidvisculus, Tj. = Disebnis viridi.f,
D. ; PI. 7. fig. 2b,c.; PL 30. group -30).
See Protococcus.

Dnjardin describes a marine species, D.
marina. Body almost globular, obtuse and
rounded in front, gi-anidar within, and (from
generic characters) with a non-contractile
tegument and two similar cilia.

He adds to this genus D. Di/nalii=3Io-
nas Dunalii, Joly, giving rise to the red
colour of the reservoirs of the salt-works of

the Mediterranean ; oval or oblong, often
constricted in the middle ; colourless when
young, greenish when older, red when
adult ; no eye-spot.

Probably marine Algas.
BiBL. i)ujardin, Inf. 340; Joly, Hist,
d'un Petit Crust ace ^-c'. 1840.

DISIPHO'NIA, Ehr.— Z>. amtralis (PI.
51. fig. \iS)=. Diato7neUa, pt,

DISO'MA, Ehr. — A genus of Infusoria,
of the family Enchelia.

Char. Body double, not ciliated : mouth
without teeth, ciliated and truncated ( = En-
cheli/s with a double body).

J), vacillans (PI. 30. fig. 45). Segments
clavate, filiform ; hvaline and narrowed at
the anterior end; lengtb 1-380 to 1-288",
In the Red Sea.

BiBL. Ehr. Infus. .302.
DIS'SODON, Grev. and Arnott.— A ge-
nus of Splachnaceas (Acrocarpous o])ercu-
late Mosses), including some Splachna of
authors and a Cyrtodon.

BiBL. Wilson, Bry. Brit. 295 ; Berkeley,
liandh. 163.

DISTEM'MA, Ehr.— A genus of Rota-
toria, of the family Hydatintea.

Char. Eves two, cervical ; foot forked.
D.forfcida (PI. 43. fig. 25; fig. 26, teeth).
Body cylindiico-conical ; eyes red ; toes
strong, recurved, toothed at the base; fr.
water; length 1-120".

Three other species, two of which are
freshwater, and one marine. In the latter,
D. marina, the cervical eye-spots are co-
lourless; if these do not really represent
eyes, this species must be referred to the
genus Pleurotrocha.

BiBL. Ehr. Infvs. p. 449.
DIST10HIA'CE..E.— Afamilyofopercu-
late Acrocarpous (terminal-fruited) Mosses,
of Cfespitose habit ; the stem increasing to-
wards the point, simjjle or branched ; the
leaves with a dorsal keel-like nerve, equi-
tant-concave, densely imbricatively overlap-
ping, parencbymatously areolated. Cells mi-
nute, with thick walls, somewhat papillose,
very densely packed, squarish. Capsules
oval, equal. British genus :

DISTIC'HIUxM, Br. and Schimper.-Ca-
lyptra dimidiate. Capsule annulate. Peri-
stome simple, with sixteen equidistant teeth,
free at the base, once or several times slit
from the base to the apex, trabeculate, deep
purple, homogeneous, smooth or rough. In-
florescence monoecious.

BiBL. Wilson. Bry. Brit. p. 104 ; Berke-
ley, Handb. p. 266.

DTSTIGMA.

[ 268 ]

DOCIDimi.

DISTIG'MA, Ehr.— A genus of Infuso-
ria, of the family Astasisea.

Char. Unattached, two blackish eye-
sp(its,

Flagelliform filaments two, one long, one
short ; motion similar to that of a leech.
Body variable in form ; freshwater.

B. protem (PL .30. fig. 4(3 a). Body
hyaline, obtuse at the ends, alternately
contracted or expanded from side to side ;
eye-spots distinct ; length 1-570 to 1-430".

B. viride (PI. 30. fig. 46 b). Body filled
with green granules, alternately contracted
and expanded ; eye-spots distinct ; length
1-570".

Two other species ; one yellow, the other
colourless.

BiBL. Ehr. Bifus. 116; Kent, L>f. 418.

DIS'TOMA, &a3rtn.— A genus of Mol-
lusca, of the order Tunicata, and family
Botiyllidaj.

Distinguished by the sessile, semicarti-
laginous, polymorphous mass ; the numerous
circidar systems ; the individuals in one or
two rows at imequal distances from a com-
mon centre, with thorax and stalked abdo-
men ; and the branchial and anal orifices
six-rayed. On marine Algie {Fuciis ^•c).

B. rubrum (PL 30. fig. 23). Mass red,
individuals yellowish; 5" in diameter, 5"
thick.

B. variohsinn. Reddish- or yellowish-
white ; bodies orange-red.

BiBL. Forbes and Hanlev, Br. Moll. i.
18.

DIS'TOMA, Zeder, or Bisfomum.—A
genus of Entozoa, of the order Sterehnintha,
and family Trematoda.

C/iar. iiody soft, depressed or cylindrical,
more or less elongated, not jointed, brown ;
furnished with two distinct suckers — one
anterior, terminal, and containing the
mouth, the other situated on the ventral
surface between the former and the middle
of the body.

Species very numerous ; Dujardin de-
scribes 164 ; most common in birds and
fishes, generally inhabiting the alimentary
canal. Each Bistoma has its separate Cer-
caria, which live in as many distinct
animals.

B. hepaticum (the fluke) occurs in the
gall-bladder and hepatic ducts of slieep
when affected with the ' rot ' ; it occurs also
in the horse, the ox, the goat, the hare, the
stag, and in man. The intestine is two-
branched, and the branches ramified.
Length 4-5 to 1}".

B. hepaticum is of special interest, on ac-
count of the immense destruction it causes
of sheep. When the young Bistoma leaves
the ovum, it resembles an obconical cilia-
ted Infusorium, with a short terminal pro-
boscis ; the cilia are subsequently cast off,
and a sporocyst or Beclia is formed, which
attaches itself to MoUusca, and in which
numerous CercaricB are then produced.
These when liberated, swim in water, and
are swallowed by sheep, or the moUusca
containing them are eaten with the grass ;
and so the young Bistomata enter the ali-
mentary canal, to take up their final abode
in the biliary ducts.

B. lanceolatmn has the intestine once
branched, then simple ; it occurs in the
liver of man, the ox, the sheep, the pig kc.

B. (Bil/iarzia) hcematohia, the African
Trematode, has the body vei-miform ; the
male I", the female 1" long. It is found
in the bloodvessels of man in Egypt, Mau-
ritius, South Africa, &c.

B. sinensis occurs in the liA'cr of the
Chinese.

Some of the species are microscopic.

BiBL. Dujardin, Helminth. 381 ; Bene-
den, Ann. Sc. Xat. 3 ser. Zool. xvii. ; Cob-
bold, Parasites, 1879, xiv. ; BoAvles, Sheep-
rot ; Tirties {remedy) Apr. 10, 1881 ; Ann.
N. H. 1880, vi. 40o; Sommer, Aymt. 1880.

DITTO LA.— A genus of Tremellini
(Basidiomycetous Fungi) consisting of
saucer-shaped -margined gelatinous Fungi,
wdth a discoid hymenium, which is at first
veiled. Bitiola radicata occurs rarely in
this country on decayed firwood. B. tiiida,
B. and Br., is considered by Tulasne syno-
UATnous with Bacrymi/ces deliquescens.
" BiBL. Alb. & Schwein. pi. 8. f . 6 ; Berk.
Oidl. p. 291.

DOCH'MIUS, Duj.— A genus of Xema-
toid Entozoa.

B. {Anchi/losfoma) ditodenalis is filiform,
the head pointed and curved ; the mouth
with four unequal converging curved teeth ;
body pointed behind in the female, blunt in
the male ; viviparous; length of male -f",
of female ^". Occurs in the human small
intestines, in Italy, Austria, Egypt, and
South America, producing anaemia and
chlorosis.

B. trigonocephalus, in the dog.

B. Sangeri, in the elephant.

BiBL. Dujardin, Helm.
Paras. 211 (fig.).

DOCIDTUM, Brebisson.— A
Desmidiacese.

/O

; Cobbold,

genus of

DOCOPHORUS.

[ 269 ]

DORYPIIORA.

Char. Cells sinp:le, straight, nincli elon-
gated, linear, sometimes atteuuatod towards
the euds; constricted in the middle, ends
truncate ; segments usuallj^ inflated at the
base.

Rabenhorst includes the species in Pleu-
7-of(enium.

Docidhnn, like Closterium, has the termi-
nal spaces with moving molecules ; and its
vesicles are either scattered or

a single longitudinal row

arranged in

D.

Sec

_. truncatum (PI. 14. fig. 38)
nients three or four times as long as broad,
with a single iuiiation at the base ; suture
projecting on each side ; length 1-80 to
1-72".

D. hacuhnn (PI. 14. fig. 39). Segments
very slender, with a single conspicuous in-
flation at the base, otherwise linear ; vesi-
cles in a single series; length 1-111".

D. nodidosum. Segments _ four to six
times as long as broad, constricted at regu-
lar intervalsso as to produce an undulated
m.argin; suture projectmg; length 1-50".
Several other species.
BiBL. Ralfs, Desmid. 155; Pritchard,
Infus. 744 ; Rab. Fl. Alg. iii. 141 ; Hobson,
Qu. Mic. Jn. iii. 18(33, 169 (Bombay).

DOCOPH'ORUS, Nitzsch.— A subgenus
oi FhUopterus (Anoplura), distinguished by
the small moveable tooth or trabecula in
front of the antenna, and the dark lines
running from them to the occiput.

D. c<jmmu7us (PI. 35. fig. 5). On Inses-
sores.

D. icterodes. Common on ducks and
geese.

DOLICHOSPER'MUM, Thwaites (P1.8.
go-. 6). — A genus of Xostochacepe, allied to
frichormus, SphaTozijga, &c., established
by Thwaites for five British species, from
which Hassall has separated one under the
name of Cuniophjium. Thwaites noticed in
this genus that "the contents escaped in an
undivided mass from the elongated and
mostly cylindrical spermatic cells (spo-
ranges), which are invariably truncated at
the ends.

D. inceqiiaJe, Ralfs. Filaments monili-
f orm ; ordinary cells at first quadrate, finally
orbicular ; vesicular cells large, spherical ;
spoi-anges linear, catenate (Ralfs,^/«j. N.H.
2 ser. V. pi. 9. fig. 1). Forming extensive
strata, composed of thick gelatinous masses
of a deep green colour, on boggy pools ;
filaments consisting of 100 to 200 cells.

D. Ralfsii (Kiitziug). Filaments moni-
liforni : ordinary cells spherical ; vesicular

cells elliptic ; sporanges elliptic or cylin-
drical, one or two in each .series. Ralfs, I. c,
pi. 9. fig. 2 ; iSplicnrozyi/a Ralfm, Thwaites,
Harvey's Algce, 2 ed. 2.")3. Cj/lindrospermum
Ralfsii, Kiitzing, Tab, Phycol. i. pi. 98. fig.
7. Forming extensive strata of a velvety
rich dark green colour, sometimes verging
tovirards aeruginous green, on rivulets and
in bogs.

D. SmitJiii, Th.^a\ies. Filaments straight,
each included in a definite gelatinous
sheath ; ordinary cells subspherical, com-
pressed, about as long as wide ; vesicular
cells subspherical, somewhat barrel-shaped,
half as wide again as the ordinary cells,
pimcta very distinct; sporanges cylindrical,
very unequal in length, and with the ends
rounded and somewhat truncated. Ralfs,
I. c. pi. 9. fig. 4. Fresliwater boggy pools.

D. Thwaitesii, Ralfs. Filaments straight,
or nearly so ; ordinary cells quadrate ; vesi-
cular cells oblong, subquadrate, puncta very
distinct; sporanges numerous, cylindrical,
with truncated ends, very variable in length
(Ralfs, I. c. pi. 9. fig. 5). SpJi(Brozyga Thw.
Harvey, Br. Algce, 2. 232. Freshwater or
brackish pools. {D. Thompsoni, Ralfs, see

CoNIOPHYXt'M.)

DOMOP'ORA, D'Orb.— A genus of Cy-
clostomatous Pol3'zoa,= Tiibulipora, pt.,
Johnstone.

2 species; deep water. (Hincks, Pol. 481.)

DO^^iaNTA, Ralfs.— A genus of Diato-
macese, = Aniphiprora with decussating
strite, but without alfe to the valves.

Pritchard describes 7 species. Raben-
horst describes 4 European, and enumerates
12 extra-European species.

BiBL. Pritchard, Infus. 920 ; Rabenh.
Flor. Alg. i. 242.

DOO'biA, Brown.— A genus of Blech-
nese (Polypodiaceous Ferns). Exotic.

DORIP'YGrS, Brady.— A genus of
Copepodous Entomostraca.

Four species ; inhabitants of the branchial
sacs of simple Ascidians. (Biadv, Copep.,
Raif Soc. i. 132.)

i)ORYPH'ORA, KUtz. — A genus of
Diatomacese.

Char. Frustules single, stalked ; valves
orbicular - lanceolate or broadly elliptical,
with a median longitudinal line, but no
nodules. Marine.

The valves are fiu^nished with transverse
or slightly radiating rows of dots.

D. amphiceros, K. (PI. 16. fig. 29 : a, side
view of frustule ; i, front view ; c, prepared
valve.) Valves orbicular-lanceolate or

DORYPIIORA.

[ 270 ]

DRAPAEXALDIA.

broadly elliptical, ends produced ; lengtli
1-500 to 1-800".

D. Boeckii, S. (Cocconenia B., K.).
Valves elongato-lanceolate, ends somewhat
obtuse; length 1-144". This species appears
to have a median and terminal nodules.

BiBL. Kiitzing, Bacill. 74, «S>. Alg. 50 ;
Smith, Diatom, i. 77 ; Rabenhorst, Fl. Aly.
i. 126 (Ilap/ioncis).

DORYPH'ORA, Illiger.— A genus of
Subpentamerous (Tetramerous, Latr.)
Coleoptera, fam. Chrysomelidse.

The very numerous species are found in
equinoctial America. The thorax or me-
sosternum is armed with a long point, pro-
jected forwards.

I), decemlineata (fig. 178*) is the Colorado

Fig. 178*.

Dorypiora decemlineata. a, natural size ; b, eggs ;
c, larva.

potato-beetle. It is of an orange-yellow
colour, each elvtrum lieing marked with 5
longitudinal, dark rough-edged striiie. The
eggs are yellow, and attached to the under
side of the leaves of the potato, to which
plant the hatched larvfe have proved so ex-
tremely destructive in America, as to have
annihilated entire crops. The beetle has
been brought over to this country by ship,
but has fortunately not become diifused and
naturalized.

An Order in Council prohibits the keep-
ing of these beetles alive, under a severe
penaltv.

DOTHID'EA, Fries.— A genus of Sphnc-
riacei (Ascomycetous Fungi), often growing
upon leaves. Distinguished from Spharia
and the more closely allied genera by the
asci being contained in cavities in the
stroma, without any distinct peritliecium.
]Slumero\is species are described as British
by Berkeley, some of which are now placed
luider other genera by himself and Fiies :
thus D.Geranii, liohertiana, Jiamuioili, Po-
tentillfe and Alchemillm of the Brit. Flora,

and D, CJt(stomium, Kze., are species of
Stigmatea in the Summa Veg. ; D. alnca
is removed to Discosia, and D. pifrenophora
and sphceroides are placed under Dothioha,
Fries, a stylosporous form. The whole of
these plants require further study, since it is
probable that they are really connected
with the SplifBronemei or Melauconiei ; for
Berkeley's observations go to show that
Asteroma TJhni is a form oi Dothidea Ulmi,
while Tulasne has found upon Dothidea
Bihesii spores or spermatia like those of
Xijlarice, others in excavated cavities having
the character of the spores of Septoria,
while in ordinary cases the surface is cov-
ered with conceptacles filled with eight-
spored asci.

BiBL. Berk. Br. Fl. ii. pt. 2. 285; Ann.
N. H. vi. 364 ; Berk, and Br. Ann. N. H.
2 ser. ix. 385 ; Fries, Suimna Veget. 386,
418 & 421 ; Corda, Ic. Fung. iv. 119 ; Tu-
lasne, Ami. Sc. Nat. 4 ser. v. 118.

BOTHIORA, Fries. See Dothidea.

DOXOCOC'CUS, Ehr.— A genus of In-
fusoria, of the family Monadina.

C/iar. No tail; no eye-spot; motion
that of an irregular kind of rolling-over.

I), ruber (PI. 30. fig. 47 a, after Ehr.).
Body globose, brick-red, more or less
opaque ; breadth 1-1728"; freshAvater.

This organism is almost beyond doubt the
same as that represented in PI. 30. fig. 24,
d and/ {nobis), i. e. a form of Trachelomonas
volvocina (Tbachelomonas). This was
suspected bv Ehrenber?.

1). puhiscidm, E. (in. 30. fig. 47 b), is
probably an early stage of the same.

The other two species — D. globulus, sub-
globose or ovate, hyaline, marine, breadth
1-804"; and D. incrqualis, subglobose, un-
equal, hyaline, speckled with green ; fresh-
water; breadth . 1-2400" — are probably
Algaj, or their spores.

BiBL. Ehr. Infus. p. 28.

DRAPARNAL'DIA,Bory.— A genus of
Chsetophoracere (Confervoid Alg?e), espe-
cially distinguished fas limited here in ac-
cordance with Kiitziug) by the filaments
being composed of an ;ixis of cells of much
greater diameter than that of the tufted cells
forming the branches (fig. 179). The spe-
cies placed here by Hassall and others, de-
void of this character, will be found under
Stigeoclomum. The green contents of
the cells form a broad band in the middle
of the cell. These plants are propagated by
4-ciliat(>d zoospores, formed from the con-
tents of the cells of the branches (fig. 180) ;

DRAPARNALDIA.

[ 271 ]

DUDRESNAIA.

aud hy restin.a-spores formed in tho same
situation aud set free by the solution of the
walls.

Fig. 170.

Fiff. 180.

Draparnaldia glomerata.

Fig. 179. Portion of a filament. Magnified 20O
dir.ms.

Fig. ISO. Portion of a branch discharging zoospores
from its cells. Magn. 400 diams.

D. glomerata, A.^. (fig. 179). Principal
filament about 1-800" iu diameter, irreau-
larly branched ; rameUi l-:?400 to 1-3000",
iu ovate tufts, generally alternate, and pa-
tent. Hassall, AUj. pL 13. 1 ; Erujl. Bot.
1 746 ; Yauch. Conferves, pi. 12. fig. 1. Com-
mon in streams and wells.

D. plumosa, Ag. Principal filaments
somewhat piunately branched, size about
the same as the preceding ramelli, in linear-
lanceolate tufts, mostly approximated to the
axis (Vauch. pi, 11. fig. 2; Ivlitzing refers
Hassairs plumosa, I. c. pi. 12. fig. 1, to D.
ojjposita, Ag. as doubtfid). Common iu
streams and wells.

D. repetita, Hass. Principal filaments
composed of repeated series of cells, each
seiies consisting of five or six cells, diminish-
ing in size from the lowest to the highest,
the series adjoining each other obliquely ;
tufts of ramelli dense, alternate. Hass. I.e.
pi. 12. fig. 2. Pare.

See SxiGEOCLONirir.

BiBL. Bory, Ann. Museum, xii. ; Yau-
cher (as Bafrachospennum), Conferves d'Bau
douce ; Link (as Charospcrmwn),IIor. Phys.
iii. ; Hassall, Ah/ce, 118; Decaisne, Ann.
Sc. Nat. 2 s6r. xvii. 314 ; Thui-et, ibid. 3 s^r.

xiv. 15; Currov, Qu. Mic. Jn. vi. 207,
pi. 9; Hicks, ibid. 1809, 383; Kabenhorst,
Fl. Alf/.m. 381.

J)11']':PAN0S'IPII0N, Koch.— a genua
of Aphidas.

D. platanoides, and I), acerina, on the
sycamore. (Buckton, Aphid., Bai/ Soc. i.
182.)

DRI'MYS, Forst.— A genus of Magno-
liacejB (Dicotyledonous Plants), remarkable
for the microscopic structure of the wood.

See WiNTEEEiE.

DRY ROT. — A peculiar decay in wood,
caused either by the presence of Fungi, as
Mendius lacrymans and Thdephorapateana,
or by a chemical process known under the
name of Eremacausis or gradual combustion.
Many remedies have beeen proposed ; sul-
phate of copper, corrosive sublimate and
creosote, especially the latter, are amongst
the most approved. In domestic architec-
tm'e, a free circulation of air and exclusion
of moisture are essential.

DRYMOGLOS'SUM, Presl.— A genus
of Grammitideaj (Polypodiaceous Ferns).
D. cornosum, exotic.

DUCTS. — A term applied in structural
botany to those forms of pjo-. 181.
the so-called vascular tissue
which consist of long tubes
constructed out of perpendi-
cular rows of cells, which are
thrown into one by the ab-
sorption of their adjoining
ends. Ducts are thus easily
distinguished from vessels,
-^ hich taper off to closed ends,
by the constrictions upon the
walls of the tubes, indicating
the junctions of the compo-
nent cells (tig. 181). See
Tissues, vegetable ;

Vi<;RSELS. Magn. 250 diams.

DUDRESNAI'A, Bonnem.— A genus of
Cryptonemiaceag (Florideous Algfe), con-
taining two minute British species, with
delicate, branched, filiform fronds, a few
inches high, of ,rose-red or reddish-brown
colom'. 1). coccinea, ■s\hich is a very rare
plant, and seldom found except on the
south coasts of England and Ireland, and
D. Hudsoni, a not uncommon sea-weed,
present very elegant microscopic structure,
the fronds being composed of a central
cellular axis, clothed with tufts of delicate,
diehotomous, moniliform filaments, stand-
ing perpendicularly upon it. The fructify-
ing process in this genus is very complicated.

J Dotted duct from
and the Melon.

DUFOUREA.

[ 272 ]

DYTISCUS.

BiBL. Harvey, Brit. Alg. 154, pi. 21 C ;
rhyc. Brit. pis. "l 10, 244; Sachs, Bot. 294.'

DITOU'REA, Ach.— A genus of Li-
cliens. D. mndreporifvrmis occurs in Swit-
zerland and Germany.

DUMOX'TIA, Lamx.— A genus of Crvp-
tonemiaceje (Florideous Algse), containing
one British species, D.Jiliformis, having a
delicate tubular frond, of yellowish.greenish,
or purple colour, of variable length and dia-
meter, with numerous filiform branches,
which are long on short fronds, and short on
long fronds ; growing commonly on rocks &c.
between tide-marks. The waU of the tube is
composed of a double layer of tissue, the
outer of roundish cells, the inner of longish
cells forming filamentous rows. The spores
are attached in clusters to the internal wall
of the tube (which is filled up with gela-
tinous substance), while the tetraspores are
found amcing the surface-cells.

BiBL. Plarvey, Brit. Alg. 147, pi. 20 a ;
Phyc. Brit. pi. o9 ; Greville, Alg. Brit. pi.
17.

DYEING. See Staining.

D YSPOXTI US, ThoreU.— A genus of Co-
pepodous Entomostraca.

D. sfriatus, in dredgings. (Brady, Copep.,
Bay Soc. iii. Go.)

DY^STE'RIA, Huxley.— A genus of
Hypotrichous Infusoria, fam. Ervilina.
Distinguished by the valves of the carapace
being united behind, but below only. Ma-
rine ; five species.

BiBL. Huxlev, Qu. M. Jn. 1857, 78;
CI. & Lachm. Inf. 284.

DYSTERI'NA,C1. & Lachm. = Ervilina.

DY^TIS'CUS, Linn., or Dg'ticns, a genus
of Coleopterous Insects of the family Dy-
tiscidpe.

Characters of the family : antennae long
and slender ; external lobe of maxilla; arti-
culated ; anterior pair of legs shorter than
the posterior pairs, which are flattened and
fringed with hairs. Freshwater.

The genus Dgtiscus is characterized by
the first three joints of the anterior tarsi in
the male being very large, and expanded
into a patella or shield; the didactyle claws;
and the maxillary palpi having the second
and third joints of equal length.

The species of Dytiscus are of large size ;
D. marginalis is common in ponds and pools.

The head is well adapted for the display
of the trophi, or organs of the moutli.
Lii brum transverse ; mandibles short and
robust, with a strong internal tooth ; max-
illae short, flat, and ciliated internally, with

the tip acute, the outer lobe palpiform : the
true maxillaiy palpi about twice as long as
the maxillfe ; mentum transverse, with the
sides produced into two lobes ; labium
short and square, palpi about twice its
length, and three-jointed. The structure
of the anterior tarsi in the male is very
curious (PI. 34. fig. Go), the three basal
joints being expanded laterally so as to
form a broad and rounded patella or shield,
convex above, and covered beneath with a
number of suckers or disks of various sizes,
some of which are stalked (fig. 6 6. a small
one). This structure enables the male to
retain his hold upon the back of the female,
the elytra of the latter being furrowed lon-
gitudinally, to aid in this effect. The three
basal joints of the tarsi of the middle pair
of legs are also flattened beneath, and co-
vered with the stalked disks.

Fig. 182.

Dytiaeus latissimus. Natural size.

Full-grown larvae about two inches in
length ; of a dark ochre or dirty brown co-
lour; the body long, subcyliudrical, and
eleven-jointed ; the two terminal joints
long and conical, the sides of the' apex
fringed with hairs. Terminal segment fur-
nished with a pair of long and slender pi-
lose appendages, by means of which the
insect can susjjend itself at the surface of
the water ; these are tubular, and commu-
nicate with the tracheae of the body. Head
(PI. 85. fig. 14) large, oval, or rounded, de-
pressed, and with live or six small elevated
tubercles near the anterior angles represen-
ting the eyes (fig. 14 a). Two rudimentary,
slender, seven-jointed antennae (A) are in-
serted in front of the eyes. The mouth

ECCRIXA.

[ 273 ]

ECHINOCOCCUS

has no aperture ; the food, consisting of the
juices of the prey, passes throuj^h a canal
ti-aversing the long, siciile-shaped, acute
mandibles (c). Maxillae (d) slender, cy-
lindrical, and termiuated by a short lateral
spine ; tht» maxillary palpi (e) are of the
same thickness, arising from the tip of the
maxilL^e, and seven-jointed. Labial palpi
(/■) slender and four-jointed, the fii'st and
third joints being very short.

The head of the larva, and the three pairs
of legs of the perfect insect, are commonly
mounted as microscopic objects, as are
those of other genera belonging to the fa-
mily— Acilius &c.

BiBL. "Westwood, Introd. &c. i. p. 95 ;
Stephens, Brit. Beetles.

E.

ECCRI'NA, Leidy. — See Enterobrt-
us.

EOHINEL'LA, Acharius. — A term ap-
plied first to a group of ova of some aquatic
animal, next to a genus of Infusoria, more
recently to a genus of Diatomaceee, but now
no lonsrer used.

ECHINOBO'TRYUM,Corda.— A doubt-
ful genus of Torulacei (Coniomycetous Fun-
gi). JE. atrum has been found in Britain,
parasitic upon a species of PacJmocybe.

BiBL. Berk, and Broome, Ann. N. H.
2 ser. V. 460 ; Corda, Icon. Fung. ii. fig. 6.

ECHINOCOCCUS, End.— A supposed
genus of Entozoa, of the order Cestoidea
and family Cystica ; now shown to consist
of the larvae of T^nia.

Char. Consisting of a vesicle of very va-
riable size, sometimes surrounded by a coat
of condensed areolar tissue, and containing
within, one or more secondary cysts ; at-
tached to the walls of these cysts, or sus-
pended in their liquid contents, are nume-
rous oblong, rounded, or oval bodies (sco-
lices), each with four suckers, and a double
crown of hooks.

E. veterinoriim, the larva of Taenia echi-
nococcus (PI. 21. figs. 1 & 2), occurs in the
liver, the cavity of the abdomen, the heart,
the voluntary muscles, and the ventricles
of the brain of man ; in the liver, lungs, &c.
of the ox, sheep, goat, ape, pig, &c. Com-
monly called hydatids. The walls of the
brood-cysts consist of numerous concentric
layers or plates, resembling those of colloid
cells or cysts. The liquid existing within

the cysts is yellowish or reddish, albumi-
nous, and frequently contains plates of cho-
lesterine, and crystals of bilifulvine (PI. 13
fig. 15) (see Bile) ; some of the latter re-
semble in form and colour those of Hjema-
TOIDINE. The scolices appear to the naked
eye as minute, white, opaque si^ecks, varying
in size from about the 1-300 to 1-100" in
length. They also vary greatly in form ;
when the head is retracted (fig. 1 a) they
appear more rounded than when this is
protruded (fig. 1 c, 1 d, If). The hooks
surrounding the anterior end of the body
(fig. 1 b) consist of a broadish basal portion,
an internal transverse blunt tooth, and a
carved terminal portion or claw ; they are
about the 1-1500 to 1-1000" in length. In
some of the scolices a kind of pedicle exists
at the base, by which they are attached to
the wall of the cyst (figs. 1 a and 1 c) ; some-
times two or more lines may be perceived,
running from the head towards the pedicle,
and connected in front by a transverse line
— probably representing vessels (fig. 1 c).
Interspersed through the substance of the
body are minute highly refractive corpus-
cles, containing carbonate of lime.

In the quite recent state, the scolices
have been seen swimming actively in the
liquid of the cyst ; this motion is produced
by cilia existing upon the surface of the
body. Mingled with the perfect scolices
are generally found some in which neither
hooks nor suckers are visible, and in which
the form is very irregular ; some of these
assume the natui'al form when treated with
acetic acid.

The scolices appear usually to be deve-
loped by gemmation from the interior of
the cysts; but, as Kuhn long since showed,
they are sometimes produced by external
gemmation (fig. 2) : the contents produce
a slight protrusion of a part of the wall of
the cyst; the protruded portion enlarges,
afterwards becoming constricted at its base,
at last probably separating from the parent,
to become itself a parent in the same man-
ner. The example figured in PI. 21. fig. 2
was not isolated ; there were many, con-
tained with numerous other larger cysts, of
the most varied sizes, all in one very large
parent cyst.

The Echinococci do not attain their full
development into Tcenice, unless they reach
the alimentary canal. The cysts and their
contents, including the Echinococci, some-
times undergo a kind of degeneration, be-

ECHINODERMATA.

[ 274 ]

ECIIIXODERMATA.

coming partially converted into fatty or
calcareous matter ; or the entire contents
become amorphous and granular, the hooks
remaining longest unaltered, but finally dis-
appearing also.

See T^NiA.

BiBL. Kuhn, Ann. Sc. Nat. 1 ser. xxix.
273; Siebold, Wiegm. Archiv, 1845, ii.
241, and Siebold und KnUiker^s Zeits. iv. ;
Dujardin, Helminth. 6:55 ; Cobbold, Paras.
112.

ECHIXODER'^MATA. — A Subkiug-
dom in the Animal Kingdom, including
the star-fishes (Asterias), the sea-hedgehogs
or sea-eggs (Echinus), the sea-slugs (IIolo-
thuria), &c.

The Echinodermata are marine animals,
' with a coriaceous or calcareous integument ;
alimentary canal distinct, suspended in the
cavity of the abdomen, and with either one
or two orifices ; distinct organs of circula-
tion and re.'^piration ; sexes usually distinct,
and external generative organs never pre-
sent; disposition of organs generally qui-
naiy ; body usually radiate or globose,
sometimes cylindrical : nervous systemform-
ing a ring generally surrounding the mouth
and giving oft" radiate branches.

A cutaneous skeleton usually exists as a
network of calcareous corpuscles (PI. 45.
fig. 1), or numerous calcareous plates pretty
regularly perforated so as to form a solid
continuous network (PI. 45. fig. 2). The
plates are sometimes moveable, at others
connected by sutures ; some are perforated
with larger apertures — the ambulacral pores;
thev are often furnished with calcareous ap-
pendages, tubercles, prickles, spines, hooks,
&c., some being imbedded in the leathery
integimient itself. Many of these appen-
dages, as well as the calcareous corpuscles,
form beautiful microscopic objects, and
possess very remarkable analytic power
(see Echinus, Synapta, and Shell) ; they
are also of importance in classification.

The muscular system consists of distinct
flattened primitive fibrils and bmidles, not
transversely striated. The organs of loco-
motion exist in the form of little tentacle-
like organs, the so-called feet or ambulacra.
These are veiy contractile hollow prolonga-
tions of the cutaneous surface, expanded at
the end, and connected by the ambulacral
pores with contractile sacs (the ambulacral
vesicles) placed on the inner surface of the
leatliery or calcareous covering of the body ;
they act as organs of adhesion and as
feelers.

In the Echinidea (-E'c///?H<s-family) and
Asteridea (Asterias-i'dmily), other curious
appendages occur, called pedicellarice (PI.
45. fig. 3) ; they are met with all over the
cutaneous surface, and consist of a forcipate
or valvular ap]iaratus, acting as organs of
prehension. The pcdicellarice of the Aste-
ridea usually consist of two or three forceps-
like or two broad valvular arms, and have
hence been divided into forcipate and val-
late pediccllarice. They are mostly without
a stalk. In the Echinidea (Echinus) they
are most numerous around the luouth, ani
have been subdivided, according to their
form, into : — 1. Gemmiform, having three
short lentil-shaped arms ; 2. Tridactyle,
having three long and laterally toothed
arms ; and 3. Ophiocephalous, with three
spoon-shaped laterally toothed arms. These
pedicellarice contain a reticular ddcareous
mass as a basis, and in Echinus are placed
upon a stalk, the lower portion of which
encloses a calcareous nucleus, whilst the
other portions are soft, extensile, and spi-
rally retractile. The pedicellaria of Echinus,
which are partially covered with ciliated
epithelium, can seize larger or smaller bodies,
and pass them from one to the other ; so
that an object grasped by one of them situ-
ated on the posterior half of the body, or
near the anal region, can be gradually
passed on towards the mouth.

The abdominal cavity of the Echinoder-
mata is always filled with sea-water, kept
in motion by cilia covering the intestinal
canal.

A true blood-vessel system, as well as the
water-vessel or ambulacral system, is also
present, into the structm-e of which and
other particulars we have no space to enter.

In their youngest state, the Echinoder-
mataconsist of infusoria-hke bilateral beings,
without organs, and swimming by means of
cilia on the surface.

BiBL. Siebold, Vergl. Anat. 74 ; Sharpey
Cycl. Anat. ^- Ihys. ii. 30 ; Agassiz, Echi-
nod. viv. ct foss. : Valentin, Echiuoderm ;
Forbes, Br. Starfishes-. Miillerand Troschel,
Asteriden;^l.\x\\>ix, Berl. Ahh. 1846-1851;
Huxley, Ann. N. H. 1851, viii. 1 ; Gosse,
Mar. Zool. i. 54 ; V. d. Iloeven, Zool. and
Sujypl. (Leuckart) ; Gegenbaur, Vergl. An.
205 ; Herapath, Qu. M. J. 18(i5, 175 (pedi-
cellarice) ; Frey, BedecJi. u-irbcll.Th. ;Koren,
Arch. Scandinar. i. 166,449; Norman, Ann.
N. II. 1865, XV. !)8 ; Stewart, Qu. M. J.
1871 ; Nicholson, Zool. 1878, 181 ; Sladen,
Ann. N. H. 1880, vi. 101 (pedicellarice).

ECIIINORTI YNC QUS.

[ 275 ]

EELS.

ECHINORHYN'CHUS, MiiUer.— A ge-
nus of Entozoa, order Acauthocephala.

Char. Body cylindrical or sacciform,
somewhat elastic, transversely rugose, ob-
tuse at both ends ; furnished with a retrac-
tile proboscis, which is armed with from
one to sixty regular transverse rows of re-
curved spines ; sexes distinct ; no mouth.

The species, which are very numerous,
many microscopic, reside in the alimentary
canal, most commonly of fishes and reptiles,
less so in that of mammals, and still more
rai'ely in that of birds.

E. anthuris (PI. 21. fig. 35) is very com-
mon in newts ; E. proteus in fish.

BiBL. IJujardin, Helminth. 483 ; Leuc-

ECHI'XUS, Lam.— A genus of Echino-
dermata, of tlie family Echinidea.

The species are popularly known as ' sea-
urchins,' or ' sea-eggs.'

The beautifully symmetrical structure of
their spines, and their curious pedicellarice,
afford favourite objects to the admirers of
nature's minute wonders. These organs are
not confined to this single genus of the
family.

See EcHixoPEEMATA and Shell.

ECTINOSO'MA, Boeck.— A genus of
Copepodous Entomostraca.

Four species ; among sea-weeds. (Brady,
Copep.^ Itay Sue. ii. 8.)

ECTOOARPA'CE^.— A family of Fu-
coideee. Olive-coloured, articulated, fili-
form sea-weeds, with sporanges (producing
ciliated zoospores) either external, attached
to the jointed ramuli, or formed out of some

of the interstitial cells.

British genera ;

* Frond rigid ; each articulation composed
of numerous cells (Sphacelarieae).

Cladostephus. Ranndi whorled.
Sphacelaria. RamuU distichous, pinna-
ted.

**

Frond flaccid ; each articulation com-
posed of a single cell.

Ectocarpiis. Frond branching; ramidi
scattered.

Myriotrichia. Frond unbranched; ra-
muli whorled, tipped with pellucid fibres.

BiBL. See the genera.

ECTOCAR'PUS, _ Lyngb.— A genus of
Ectocai-pacese (Fucoid Algae), consisting of
olive or Drown sea-weeds, with fronds com-
posed of flaccid capillary filaments, growing
between tide-marks or upon other Algse.

Fig. 183.

Eotocarpiis
verminosus.

Filaments of very simple
structure, the main axes or
branches being composed of ,
single rows of cells (tig. 183), \
as in Vladophora. The re-
productive bodies at present
known, ciliated zoospores, are
formed in the cells of the
branches, sometimes in the
terminal cells, producing the
siliquose or elliptical (fig.
183) sporanges, and some-
times in interstitial cells, be-
yond which the branch is
prolonged into a tine filament.
In E. siliculosus the extremi-
ties of the branches are con-
verted into sporanges : the Portion of a fl-
cell-contents first divide into J''"^'''^* ^'^.^""S

, „, 1 -1 ii lateral ellipti-

a number ot layers, while the cal sporanges.
part of the filament contain- Magn. 50 diama.
ing these swells up and ac-
quires the pod-like form ; the layers of con-
tents are then resolved into lines of zoo-
spores piled regularly one above another.
The summit of the pod finally bm'sts, and
the zoospores escape. The empty sporange
exhibits fine transverse strige, as if delicate
septa existed between the layers of zoo-
spores. In E. litoralis, Harv., the fertile
cells are not terminal, but interstitial, and
form beaded rows surmounted by a hair-
like prolongation of the branch ; the zoo-
spores escape by a lateral pore. The germi-
nation of these zoospores has been observed
by Thm'et. Sixteen British species (Har-
vey), some of which are common, particu-
larly the two above mentioned.

BiBL. Harvey, Mar. Alg. 58, pi. 9c;
Phyc. Brit. pis. 162, 197, &c. ; Eng. Bot.
pis. 2290, 2319, &c. ; Thuret, Ann. Sc. Nat. 3
ser. xiv. 234, pi. 24. figs. 1-7 ; Agardh, Ann.
Sc. Nat. 2 ser. vi. 197 ; Crouan, ibid. xii.
p. 248, pi. 5.

ECTOPLETJ'RA, Agassiz.— A genus of
Hydroid Zoophytes, fam. TubulariidaB.

E. Dumortierii. Isle of Man, Ostend.

BiBL. Hincks, Brit. Zooj^h. 124.

EEL {Anguilla). — It is popularly believed
that the eel has no scales. They are, how-
ever, present, but immersed in the skin ; and
their structure is curiotis (Scales of Fish),
The dried skin of the Eel, mounted in
Canada balsam, exhibits well the scales,
covered by the epidermis, and the beautiful
layer of stellate pigment-cells.

EiBL. Yarrell, Brit. Fishes, ii.

EELS, in paste (ANGurLLULAGLUTixis).

t2

j:els.

[ 276 ]

EL.EAGNACE^.

EELS, in vinegar (ANGurLLrxA aceti).

EGGS. — The minute ova of certain ani-
mals have alwaysbeen favourite microscopic
objects on account of their cmious forms, the
beautiful stmcture of their outer chitinous
envelope, their varied colours, and the sin-
gular lids with which some of them are
furnished. The most interesting are those
of insects : among them we may mention
the brown eggs of the puss-moth, Cerura
vinula (PL 39. fig. 19) ; of the large and
small cabbage-butterflies, Pontia bmssicce
and rajjce (PL 39. fig. 21) ; of the small
tortoiseshell butterfly, Vanessa urticce ; the
angle-shades moth, JVoctua or Phhxjophora
meticulosa ; the common meadow brown
butterfly, Hipparchia Janira ; the biimstone
moth, iltimia cratagata ; the water-scorpion,
Nepa ranatra ; the common cow-dung-fly,
Scaiophaga stercoraria, which are very

-dmif

the
20),

bug-, Cimex

Hxjdrometra

common on cow-.^ii±ig ,
lectidarius (PI, 39. fig.
stagnorum, &c.

Their surfaces exhibit markings of the
most varied forms — spines, tubercles, pits or
processes, sometimes of considerable length
(PL 21. figs. 22, 23), often arranged with
great symmetry, and frequently closely re-
sembling the cellular structure of plants in
appearance. Sometimes very delicate an-
gular spaces are mapped out upon them, the
intervals being most minutely dotted, as in
the eggs of the common blow-fly, Musca
vomitoria (PL 34. fig. 35).

It is a general fact, exemplified in both
the animal and vegetable kingdom, that
imicel hilar, or the corresponding stages or
phases of the higher organisms, exhibit
markings of some kind upon their external
membrane or wall, as is seen in the cells
of the Desmidiaceae, the Diatomacete, the
eggs of animals, the spores and pollen-grains,
and the seeds of plants,

At certain seasons of the year, the eggs
of some aquatic animals are provided with
a veiy thick horny coat, as in the Entomos-
traca, Hydra, &c. These have been called
winter ova, from the notion that here was
a defence against a low temperature ; they
conespond to the resting-spores or resting-
stages of the Infusoria and Al^se, some of
which were formerly included in the ani-
mal kingdom. The formation of this coat
can scarcely have any relation to tempera-
ture, either from its structure or from its
requirement in an organism which has no
heat to retain. Its presence would be per-
fectly intelligible, however, as a means of

protection from evaporation when the
pools become dry ; and for this purpose its
structure is well adapted. It might also
afford a protection against the attacks of
predatory animals, many of which could
easily devour an ovarian ovum, while they
could not break through the homy cases of
the winter ova ; and these winter ova are
only formed when the ova are not to be
hatched soon after extrusion from the pa-
rent. The ova of those animals which are
never hatched immediately after leaving
the parent, have always a coat correspond-
ing to that of the winter ova.

The structure and development of eggs
are considered under Ovum; see also Shell.
BiBL. See Ovum.

EHRENBERGI'NA, Eeuss.— A Cassi-
duline Foraminifer with the later portion
of the shell uncoiled.

BiBL. Carpenter, Inirod. Foram. 198.
ELACHIS'TEA, Fries. — A genus of
Myrionemacefe (Fucoid Algae). Minute
epiphytic sea-weeds, consisting of a dense
tuft of simple, articulated, olivaceous fila-
ments, fi-om a common tubercular base
composed of a closely combined mass of
dichotomously branched filaments, growing
upon larger Fucoids, such as Fucus, Hi-
manthalia, Cystoseira, &c. The fructifica-
tion is borne in two forms — unilocular
(spores, Harvey) and multilocular sporanges
{paraneinata, Harvey). The unilocular are
formed of metamorphosed terminal cells at
the ends of the dichotomous filaments; they
are long ovoid sacs, the contents of which
are ultimately converted into a vast number
of zoospores. The multilocular sporanges
arise exactly in the same place and way,
but take the form of long, slender, articu-
lated filaments, in the joints of which simi-
lar but smaller zoospores are developed.
Both forms of fructification nestle on the
surface of the tubercle of the frond, at the
base of the long simple filaments. The
zoospores of both kinds of fruit germinate ;
and these occur together in some cases (JS.
attenuata), in others at different seasons of
the year. Harvey describes seven British
species; the tufts of some are half an inch
long, of others less than a line.

BiBL. Harvey, Mor. Alg. 49, pL 10 F ;
Phyc. Brit. pls.'240, 2(50, 261, &c. ; DiUw.
Conferv. pi. 66 &c. ; Thuret, Ann. Sc. Nat.
3 ser. xiv. p. 236, pi. 25. figs. 1-4.

EL^AGNA'CEyE.— A family of Dico-
tyledons, the leaves of which are usually
covered with a kind of scurf formed of very

ELAPHOMVCES.

[ 277 ] ELASTIC LIGAMENTS.

elegant microscopic scales. See Hairs, and

HlPPOPHAE.

ELAPHOMY'CES, Nees.— A genus of
Tuberacei (Ascomjcetous Fungi) consist-
ing of subterraneous truffle-like plants, with
a "vvarty or hairy rind, not bursting sponta-
neously, but divided into little chambers
internally by intersecting plates of sporife-
rous tissue. The spores are formed in sacs
(asci) {tig. 185), from four to eight in each,
ai'ising fi-om branched anastomosing fila-
ments {capiUitium). Three species are
found in this country : — E, anthracinus,
Vitt., in clayey ground; E. granulatus,
growing in heathy groimd ; and E. muri-
catus, Fr. {E. variegatus, Vitt., Tulasne),
attached to the rootlets of beeches. L. and
C. Tulasne have carefully analyzed this
genus.

BiBL. Berk. Br. Fl. ii. pt. 2. 306 ; Ann.
N. H. vi. 4-30, pi. 11. fig. 10 : L. and 0. Tu-
lasne, Ann. Sc. Xat. 2ser. xvi.p.5,pls. 1-4;
Hypog. Fungi, 1850 ; Vittadini, Monog. Tu-
ber. App. 66, &c., pis. 3 & 4 J Berk. & Br.
Ann. N. H. xviii. 81.

Fig. 184.

Fio-. 185.

Fig. 184. Elaphomyces hirtns. Section, nat. size.

Fig. 18.5. E. variegatua. Filaments of capiUitium,
with asci containing spores, and also loose spores
wiiich have escaped. Magnified 300 diameters.

ELASTIC LIGAMENTS.— These are

yellowish strong bands, consisting of elastic
or yellow fibrous tissue, with a small quan-
tity of connective tissue. They are met with
connecting the arches of the vertebrae (liga-

menta subflava), in the stylo-hyoid and in-
ternal lateral ligaments of the jaw, and the

186.

Transverse section of the ligamentum nuchse of an
ox, after treatment with solution of caustic soda : a,
connectiTe tissue, appearing transparent ; 6, section of
elastic fibres. Magnified .350 diameters.

ligamentum nuchae, or 'paxy-waxy,' of ani-
mals. They contain but few vessels, and
no nerves. The elastic fibres (fig. 187) are
from 1-7500 to 1-3500" in breadth, slightly
flattened (fig. 186), mixed with still finer
and some coarser elastic fibres, formino; a
dense network, taking a general direction
parallel to the long axis of the spine. Be-
tween these fibres are loose undulating

Fig. 187.

Elastic fibres! a, from a human Hgamentam snbfla-
vum, with intervening connective tissue, b. Magnified

450 diameters.

bundles of connective tissue, running paral-
lel to the elastic fibres.

BiBL. Kdlliker, Mik. An. ii. 306, and

ELASTIC TISSUE.

[ 278 ]

ELASTIC TISSUE.

Gewehel. d. Mensch. ; RoUett, Strieker's
Getveb. i. 59.

ELASTIC TISSUE of animals, or yel-
low fibrous tissue, occurs in the ligamenta
siibiiava of the vertebrae, iu the thyro-byoid
and cricoid membranes, the vocal chords,
the trachea, forming the longitudinal elastic
bands of that tube and its branches, in the
internal lateral ligament of the javf, the
stylo-hyoid ligament, the transversalis fas-
cia of the abdomen, the blood-vessels, and
almost everywhere mixed with the fibres
of connective tissue.

It differs from white fibrous tissue in its
elasticity and its yellow colour. But some
physiologists regard it as a variety of this.

Its elementary form is that of round or
flattened fibres, varying in size from an
almost immeasurable tenuity to that of
1-2200" or even more ; the finer ones have
been termed nuclear fibres by the Germans ;
they are either isolated, arranged in bundles,
or branching and anastomosing (fig. 1S9),
sometimes undulating or spiral, at others
nearly straight. When brolcen, they curl
up, the ends appearing abrupt or truncated.
They are highly refractive, their edges
appearing dark, well-defined, and mostly
smooth, but sometimes toothed or serrated.
Sometimes they exhibit transverse cracks
upon the smface.

Fig. 188.

Fig. 189.

Fig. 188. Nebvork of elastic tissue, from the ixiiilillo
coat of the pulmonary artery of the horse. Maguilitd
350 diameters

Fig. 189. Network of fine elastic fibres from the
peritoneum of a child. Magnilied 350 diameters.

They are easily distinguishable from fibres
of connective tissue by the use of acetic acid,

which has little or no effect upon them; and
this is also the case with solution of potash.
Sometimes by their anastomoses they form
fibrous networks [tig. 189), or plates perfo-
rated irregularly by holes — fenestrated
membranes (Hg. 188). The fibres are also
themselves sometimes transversely perfo-
rated by irregular rounded apertures.

Chemically, elastic tissue consists of elas-
tine. It is coloured red by Millou's test,
but not by that of Pettenkofer, and does
not yield gelatine by boiling.

Elastic tissue is probably developed from
cells. In all parts of embryos where elastic
tissue occurs, peculiar fusiform or stellate
cells (fig. 190 a) with acute ends or pro-
cesses are met with, by the fusion of wliich
(fig. 190 b & 191) long fibres or networks
are formed, in which the spots correspond-
ing to the cells at first form dilatations with
elongated nuclei. The fibres frequently
remain in this condition, forming a modifi-
cation of tlie so-called nuclear fibres ; or

Fig. 190.

Fig. 191.

Fig. 190. Formative cells of elastic tissue, from the
tendo Achillis: a, of a four months' embryo; 6, of a
seven months' fcetus ; some of the cells are free, with
one or two processes, others fused in twos and threes.
Magnified 3.i0 diameters.

Fig. 191. !-'tellate formative cells of nuclear fibres,
from the teiido Anhillis of a newly born infant. Mag-
nified 350 diameters.

ELASTINE.

[ 279 ]

ELYTRA.

all traces of the original composition vanish,
uniform fibres or networks alono roniaining'.
There is. however, great dill'erence of ( )pi niou
among physiologists as to the development
of elastic tissue, some regarding it as arising
from librillatiou of the intercellular sub-
stance.

Elastic tissue occurs in the same situations
in all classes of the Vertebrata as in man —
also in some special localities, as in tlie
ligaments of the claws of the cat, the folds
of the wing-membrane, and tlie pulmonary
sacs of birds. In the luvertebrata, this
tissue appears to occur but rarely ; and it is
uncertain whether the elastic ligaments
existing in them, e.g. those oi the mollusca,
agree anatomically and chemicallj' with the
elastic tissue of the higher animals or not.

BiBL. KiiUiker, Gewehel.; Reichert, MM.
Archiv, 1850, lift. vi. o5 ; Leydig, Hist. 27 ;
Frey, Histol. 1876 (very complete litera-
ture), 24:6 ; Beale, Simple Tissues ; RoUett,
Strieker's Handb. i. 59.

ELASTINE. — The proximate chemical
principle of which elastic tissue consists.

EL'ATERS. — This name is applied to
two forms of structure occm-ring in the
higher Cryptogamous Plants. The elHptical
spores of the Eqnisetaceje are furnished
with what are called elaters, viz. four elastic
filaments, attached about the middle of one
side, which are coiled once or twice round
the spore before it is discharged from the
capsule, in the position where they were
originally developed ; but when the spore
is discharged, they uncoil with elasticity,
causing the spore to be jerked away. They
appear to be produced by the outer coat of
the spore splitting in spiral fissures, and
separating in ribands from the inner coat.
See Equi.setace^.

The elaters of the Liverworts or Hepa-
ticse are of difierent nature ; they consist
of more or less elongated delicate mem-
branous tubes, which are closed cells, inside
which one or more elastic spiral fibres are
coiled up. They occur mixed with the
spores in the capsules of the Jungermanniepe,
sometimes attached to the valves ; they
here mostly present the appearance of cy-
lindrical celhiJo.se tubes, closed at the ends,
with a flat spiral band coiled in an open
spiral, adherent to the cell-membrane form-
ing the Willi (PL 40. tig. 38). The elaters
found among the spores of Marehantia poly-
morpha (PL 40. figs. 36, 37) are very long,
and contain a double coil, the ends of the
two fibres coalescing into a loop at each

extremity (PI. 40. fig. 37 b) ; so that the
entire fibre may be compared to a piece
of string with its ends united, and laid out
so as to represent two cords, side by side,
which are then twisted spirally round one
another. In Targioni.v the tubes are
sometimes branched. The development of
the spiral fibres is similar to that of the
spiral fibres of vessels. See Hepatic^e.

Structures apparently analogous to these
elaters of the Ilepaticae occur in some of
the Myxogastrous Fungi, as in Tuichia
(PL 40. fig. 39«) ; while in other genera of
this family filamentous bodies occur, either
plain or obscurely marked. In Batarrea
also, one of the Puft-balls, a kind of elater
exists accompanying the spores ( see Trio ho-
G ASTRES ). It has been stated by Schleiden
and Schacht that the elaters of these Fungi
are solid filaments with spiral ridges upon
them, or flat solid ribands twisted on their
longitudinal axis. This statement is at
variance with our observations, and is not
borne out by the drawings given by these
authors themselves. CuiTey, while also
contesting Schleiden's view, states that the
spiral line is a ridge outside a tube, — a con-
dition of things unlike any thing else we are
acquainted with in vegetables.

The elaters of Trichia require a very high
power for their elucidation, an eighth or
twelfth, with a high eyepiece, and a good
light ; they may then be seen to consist of
tubes with spiral fibrous secondary deposits
upon the iiiside of their walls (PL 40. fig. 40).
See Spiral Structure.s.

BiBL. See EQUisETACEiE, Marchantia,
Trichia, and Spiral Structures.

ELDER. — Samhueus niger, the common
Elder tree (Caprifoliaceaj, Dicotyledons), is
remarkable for the great development of its
pith ; sections of thisfuruish very accessible
and convenient illustrations of
parenchyma.

ELLlPSOIDI'NA, Seguenza.— An egg-
shaped hyaline Foraminifer, probably Cryp-
tostegian. The adult has three concentric
chambers, one within another, touching at
their bases and kept apart at the apices by
an internal column. An irregular septal
orifice surrounds the column as it passes
through the chamher-waU. E. ellipsoides
and its varieties only are known. From
the Mid-Tertiary beds of Sicily.

BiBL. Brady, Ann. N. H. 1808, i. p. 333.

ELYTRA. — The horny anterior pair of
wrings of the Coleoptera ; sometimes called
wing-covers or wing-cases, because thuy

vegetable

EMBRYO.

[ 280 ]

EMBRYO.

cover and protect the subjacent pair of
membranous wings of these insects when
not in use.

The elytra may be regarded as consisting
of an elongated, depressed fold of the inte-
gument, comparable to the web between the
fingers, or that of the bat's wing. Four
structures are distiuguishable in them : —
1, an outer, firmly adherent, epidermic layer,
composed of minute cells, frequently un-
distinguishable, or at least only to be de-
tected in parts ; this layer is continued
around the margins of the elytra, so as to
cover their inferior surface also, forming, 2,
the inner epidermic layer, in which the cells
are stated to be less distinct, more rounded,
and more closely placed than those in the
upper layer, hence presenting a more di-
stinctly angular form ; this layer is easily
detached from the elytra, and its surface
next the body of the insect is frequently
furnished with a number of very minute
hairs, or spiniform papillfe directed back-
wards (PI. 34. fig. 2). Beneath the outer
epidermic layer is 3, a layer of dark resinous
pigment ; whether contained in cells or not
has not been determined. 4, an intermediate
portion, composing the principal thickness
of the elytrum, representing the two fused
strata of the cutis, and consisting of a number
of fibres, running in different directions,
variously interlacing, anastomosing, and
crossing, so as to form numerous plates or
secondary layers, many of which present a
fenestrated appearance ; as many as sixteen
of these plates have been separated.

The veins or nerves of the elytra .either
traverse the intermediate thick layer of the
elytra, or run between its under surface and
the inner epidennic layer, to which they
sonir'times remain adherent. See Insects.

The structure of the elytra can only be
made out by macerating them for a long
time in solution of caustic potash, or water.

BiBL. Schmidt, Tai/lor's Sc. Memoirs,
V. IG; Meyer, MilUer's Archiv, 1842, 12;
Nicolet, Ann. Sc. Nat. 3 s^r. vii. ; and the

BiBL. OF IXSECTS.

EMBRY'O, OF Plaxts.— This is the
name applied to the rudimentary plant con-
tained in all true seeds. Seeds cnnt'\ining
embryos are borne exclusively by Flowering
Plants ; and while the external conditions
under wliich the seeds are produced afford
the character for the first subdivision of this
province of the Vegetable Kingdom (Ax-
GIOSPKRMS and Gymxosperms), the struc-
tui'e of the embryo is taken as the most

striking character in further subdividing the
Angiospermous Flowering Plants into their
two great natural groups, viz. Monocotyle-
dons and Dicotyledons, in which, respect-
ively, the embryo bears one or two cotyle-
dons or seed-leaves. Cases occur both
among the Dicotyledons and the Monocot}--
ledons where the typical structure is de-
parted from. ThusinOrobanchaceJB (Dico-
tyledons) the embiyo is a mere globular
mass of cellular tissue, the result of an arrest
of development, the cotyledons and radicle
never becoming distinct ; the same is the
case in the Orchidaceae among the Monoco-
tyledons, the embryo not advancing beyond
the state of a globular mass of parenchyma.
The relation of such embryos to the perfect
forms is well illustrated by comparing the
stages of gi'owth of embryos which acquire
fully-developed cotyledons and radicle (fig.
192). In Cuscuta, a leafless plant, the

Fig. 192.

A young Dicotyledonous embryo in successive stages
of (ievelopment. All exhibit the suspensor; and 4 has
the cotyledons appearing, separated by a notch. Mag-
nified 50 diameters.

embryo has no distinct cotyledons. Other
anomalies of another kind also occur. Some
Monocotyledons, such as those of Grasses,
have the rudiment of a second cotyledon ;
but this is above and not opposite the other
larger one. In Dicotyledons the cot^dedons
are not unfrequently unequal, and some-
times soldered together. In the Coniferae
the embryos appear to have four, eight, or
more cotyledons in different cases ; but it is
stated that there exist only two, divided or
compound, cotyledons (see Seeds),

Occasionally more than one embryo occurs
in a seed (see Polyembeyoxy) ; and in the
Coniferae a number of embryos are at first
produced, of which one only becomes per-
fectly developed (see Gyjixospermia).

The enibrvo sometimes constitutes the
whole mass of the seed, merely enclosed in
the coats ; in other cases it is embedded in
a mass of albumem. In the former case the
tissue of the cotyledons often assumes cha-
racters similar to those of the albumex,
serving as a receptacle for stored nutriment
for the germinating plant, in the form of

EMBRYO-SAC.

[ 281 ]

ENCALYPTA.

fleshy secondary deposits, starch, oil, Szc.
The position of the embryo in the albumen,
or the modes in which the embryo is folded
up within the seed-coats, are of great im-
portance in systematic botany, for the charac-
terization of families. Particulars regarding
these points, and the manner of examining
them, are given under the head of Seed.
The development of embryos is described
under Ovule. See also Orchidace^,
Orobanchace^, Cuscuta.

BiBL. Henfrey - Masters, Bot. 634 ;
Brongniart, Ann. Sc. Nat. xii. 14, &c. ;
Jussieu, ibid. 2 s6r. xi. 341 ; St.-Hilaire,
Ann. Sc. Nat. 2 ser. v. 193 ; Duchartre,
Ann. Sc. Nat. 3 ser. x. 207 ; Hofmeister,
Abh. sdchs. Ges. Wiss. vi. & vii. ; Sachs,
Bot. 553; and the Bibl. of the articles
Ovule, Seed, &c., ahove referred to.

EMBRYO-SAO, of Plaints.— A cell
which becomes enlarged into a sac in the
substance of the upper part of the nucleus
of the ovule or rudiment of the seed. In
the cavity of this are developed the germinal
vesicles (PL 47. figs. 3, 4, 5), one of which
(occasionally more), after fertilization, gives
origin to the Embryo. The most common
condition of the embryo-sacis tliatof a large
cavity excavated in the nucleus, bounded by
its own cell-membrane, and containing abun-
dant protoplasm, and subsequent^ germinal
vesicles and endosperm-cells (see Ovule).
Not uufrequently, however, it becomes de-
veloped into diverse saccate processes, either
pushing their way through the substance of
the nucleus in variable directions (Scrophu-
lariace(B itc), or emerging from the micro-
pyle, coming to meet the pollen-tube ( Vis-
cum), or even so much developed externally
that the embryo is formed and perfected
altogether outside the nucleus (Santahan).
These and other conditions are further de-
scribed under Ovule. When the germinal
vesicle is fei'tilized, and is imdergoing deve-
lopment to produce the embryo, the embryo-
sac often becomes completely filled with
endosperm-ceUs, at first free, but afterwards
adhering together through their crowded
condition. These may persist and form an
endosperm to the seed, as in Nuphar, where
there is an additional episperm formed out-
side the embryo-sac from the substance of the
nucleus. Albuminous seeds generally have
either an episperm or an endosperm alone.
In exalbuminous seeds the endosperm ori-
ginally existing inside the embryo-sac be-
comes absorbed through the pressure of the
growing embryo, the embryo gradually fiJHng

up the cavity, and by further expansion ob-
literating the embryo-sac and nucleus. See
Albumen, of Seecls.

In the Coniferae the embryo-sac, origi-
nally formed by the excessive expansion of
one of the cells near the apex of the nucleus,
becomes subsequently filled up by cellular
tissue, in the upper part of which become
developed the bodies called corpuscula, each
of which possesses a kind of secondary
embryo-sac of its own, in which the ger-
minal vesicles are developed (see Gymno-
spermia).

The term embryo-sac might also be ap-
plied to the large cell at the base of the
archegonia of the Ferns, Lycopodiace^,
Mosses.

Bibl. See Ovule and Gymnospermia.

EMPUSI'NA, Cohn. See Sporendo-
nema.

EMYDTUM, Doyere (Echiniscm,
Schultze). — A genus of Arachnida, order
Colopoda, family Tardigrada.

Char. Head furnished with appendages ;
mouth conical, without appendages or ter-
minal sucker ; epidermis semisolid, present-
ing, especially on the upper surface of the
body, an evident annular division.

A testudo (PI. 50. fig. 7). Reddish-
brown ; body ovoid, opaque ; snout conical,
presenting traces of division into three
rings ; head indistinctly divided into three
segments, the first and third presenting short
setiform filaments supported upon ver}^ short
tubercles, the second with a palpiform, blunt
and flattened appendage ; pharyngeal tube
very slender; stj-les straight ; bulb without
an internal jointed framework; eye-spots
small, oval, simple, most visible at the
under aspect of the body; trunk divided
into four simple rings, with spines and long
filaments; legs three-jointed, each with
large and strong claws, the posterior pair
with a kind of spur also at the back part of
the lower margin of the second joint; move-
ment excessively slow ; length, from the
end of the extended snout to the posterior
border of the fourth ring, 1-80". Found on
the moss covering tiled roofs ; common.

E. spinulosum \

77 14 \ rare.

±j. granulatum \

Bibl. Doyere, Ann. Sc. Nat. xiv. p. 279

ENALLdSTE'GIA. — One of D'Or-

bigny's orders of Foraminifera, having the

chambers alternate in two or three rows,

not spiral ; such as Polymorphina and Tex~

tularia.

ENCALYP'TA, Schreb.— Agenusof Ca-

ENCALYPTA.

[ 282 ]

ENCIIELYS.

lymperacese (Pottioid Mosses), containing
several British species.

BiBL. Wilson, Bryol. Br. 140; Berk.
Handh. 246.

Fig. 193.

Fig. 194.

^mmm

Enoalypta commutata.

Fig. 193. A single plant. Magnified .5 diameters.
Fig. 194. The mouth uf the capsule, showing the
rudimentary peristome. Magnified 50 diameters.

Fig. 195.

Fig. 196.

Enoalypta commutata.

Fig. 19.5. Capsule on stalk, with vaginule at base,
and calyptra above. 10 diameters.

Fig. 19(5. Capsule enclosed in its cah'ptra. 20 di-
ameters.

ENCEPH'ALOID, or Enceph.^loid
C.\NCER. — That form of cancer in which
the morbid substance has the appearance
and consistence of the medullarv part of the
brain; hence sometimes called medullary
cancer.

See Tumours, Cancerous.

ENCHE'LIA, Ehr.— A family of Infu-
soria.

Char. No carapace, ciliated, oral and
anal -orifices at opposite ends of the body. .

Ehrenberg distinguishes the genera thus :

f^mgle} ^"^*^^^-

/"Mouth I

directly | , I i

trun- i '^l^U
! cate, no I '=^'^1
S lip V ( double . . .Disoma.

Mouth oblique- / i -7t • i j

Iv truncate,with t °°"''f'^ Tru'h,Hl<,. _
I ij k a neck Lucryinaria.

i

Sur-
face
with
very

Mouth fine

t loth- -j cilia

less

Sur-
face
with
evi
dent
^cilia

Mouth with te eth Prorodon.

Mouth obliquely trim- ) t i

cate, with a lip f Leucophrys.

Mouth directh' trun- \ tt i i
cate, without a lip ,„\SoJopkrya.

Dnjardin's family Enchelia bears no re-
lation to that of Ehrenberg. He defines it
as consisting of animals partly or entirely
covei'ed with diffused cilia, no mouth ; and
subdivides it thus : —

ciHated (. *^'^i^ ^t one end Acomia,

all over f ^'^'^ '^ ^ longitudinal furrow Gastrochtsta.

/"Cilia all alike Enckefys.

r>-r„*„^ Both cilia and trailing ) . ,

S'/'**«'^-l retractile filaments [ Alyscnm.

an o\er | q^^^ j^^ straiglit I

U'ilium pSsterioriy ) Vronema.

Kent includes in the family : Enclielys,
3{efaci/stis, Perispira, AnopJuys, Colpoda,
and Tillina.

ENCIIEL' Y0D0N,01.&Lach.— A genus
of Holotiichons Infusoria.

Char. Free, ovate, narrowed in front;
mouth terminal, with a longitudinally pli-
cate oesophagus.

Two species ; freshwater and marine. (CI.
& Eachni. Inf. .316: Kent, Inf. oO-^.)

EN'CIIELYS, Hill.— A genus of Infu-
soria, family Enchelia, Ehr. "(Tii--^cnELiNA,
CI. & Each*.).

Char. Body single, ovate, free, very finely
ciliated on the surface ; mouth without
teeth, ciliated, directly truncated. Bog-
water and infusions.

E. pupa, E. (PI. ;30. fig. 48) . P.ody ovate,
turgid, attenuated in front, contaiuiug j-el-
lowish-green granules; length 1-144".

ENCHONDROMA.

[ 283 ]

ENDOSMOSE,

E. farcimen. Smaller than the last,
1-14;V2"; intornally whitish.

E. arcuatit, (,'1.

Two other species.

Diijardiu's genus Enchehjs belongs to Cy-
clidium.

BiBL. Ehrenb. Inf. 298 ; Dujanlin, Inf.
385; Stein, Inf. 137; Clap. & La:hm,/«y.
309 : Kent, Inf. o09.

ENCHONDRO'MA. See Tumours.

EXC YONE'MA,Kutz.— A genus of Dia-
tomaceiB.

Char. Frustules resembling those of Cym-
bella, arranged mostly in longitudinal series,
in gelatinous tubes; freshwater.

Valves very variable in form, even in the
same tube, showing how httle dependence
is to be placed upon this feature as a cha-

E. prostratum (PI. 19. fig. 10). Fila-
ments nearly simple; length of frustules
1-1560 to 1-600".

E. cfpspitositm. Filaments divided at the
ends, tufted.

2 other European species, and 2 foreign.

BiBL. KiitzLng, BacUl. 82, and Sp. Alq.
61; Ralfs, Ann. X. II. 1845, xvi. Ill;
Berkeley, ib. 1811, vii. 449 ; Smith, Brit.
Diat. ii.'68; liabenhorst, Fl. AUj. i. 85.

ENDIC'TYA, Ehr.=CosciNODiscus in
part. E. oceanica=C. or. K.

ENDOCARTOX, Hedw^— A genus of
Lichens, tribe Pyrenocarpei, with pale peri-
thecia immersed in a peltale or squamiform
coriaceous thallus ; gi-owing on rocks, in
streams, and on the ground.

4 British species : E. miniatum,Jluviatile,
rufescens, and hepaticu'rn.

BiBL. Leighton, Angioc. Lich., Ecn/ Soc.
1851, 10, pi. 1, and Lidi. Fl. 441 ; Tulasne,
Ann. Sc. Nat. 3 ser. xvii. 90, 218, ])ls. 10 &
12; Hook. Br. Fl. ii. pt. 1. 159; Schajrer,
Enum. 230, pi. 9. fig. 2.

EX'DOCHROME.— This term is applied
to the cell-contents, or the miscellaneous
collection of substances and structures en-
closed in the cavity of a cell. In an Alga,
therefore, like Zygnema, it comprehends
the pritnordial utricle or layer of protoplasm
lining the cell-wall, together with the
chlorophyll-globules or vesicles, starch -
grauides, nucleus, and liquid and granular
protoplasm contained in the cavity of the
cell. It is perhaps a useful word in rouglily
describing a species, but it is too indefinite
to be admissible in any accurate description
of cellular structures ; moreover, as it is
not a definite collection of substances, nor

always coloured, the use of the term cell-
contents is to be preferred in all cases, as
not indicating any positive characters.

EXDOCOCCUS, Nyl.— A genus of Li-
chens containing the parasitic species of
Verrucaria.

BiBL. Leighton, Lich. Fl. 492.

EXDODRO'MIA, Berk. A curious ge-
nus of Mucorini (Phycomycetous Fungi),
distinguished by a very delicate vesicle per-
forated by the stem, filled with delicate
branched radiating threads and globose
spores, each of which has a nucleus en-
dowed with active motion. E. vitrea, the
only species, is found on sticks in damp
woods.

BiBL. HooTc. Jn. iii. 79 ; Berk. Outl. 408.

EX'DOCtEN. See Monocotyledons.

EXUO'GONE, Lk.— A genus of Muco-
rini (Phycomycetous Fungi), consisting of
one or two Ilypogaeous species, the flocci
being collected into a globose spongy mass,
and terminated by globose vesicles, solitary
or in fascicles. Two species, E. pisiformisj
Lk., and E. lactijlua, B. & Br., have been
found in this country.

BiBL. Atm. N. H. 1846, xviii. 81 ; Berk.
Ouil. 409.

ENDOS'MOSE, Osmosis or Dialysis.—
This name is applied to a phenomenon
which takes place when two difl'erent li-
quids, having an attraction for each other,
are separated merely by a porous diaphrag-m
or an organic membrane. A diffusion takes
place, by which the liquids become mixed,
but one of them flows more rapidly into
the other. Thus when alcohol and Vater
are so placed, the water flows into the
alcohol (endosmose) much more strongly
than the alcohol into the water (exosmose).
The same attraction occurs when syrup or
a solution of gum is substituted "for the
spirit, and also alkaline salts. When acids
or acid salts are placed in the same relation
to water, the current is strongest towards
the water. Acids and alkaline solutions
exert the strongest action, neutral sub-
stances the weakest. Dilute solutions act
more efficiently (proportionally) than strong
ones. The importance of the effects of
endosmose on microscopic objects viewed in
liquids, has been mentioned in the Introd.
(p. xli). Delicate structures are often ad-
vantageously wetted with dilute solution
of sugar, common salt, or glycerine, to
prevent the changes from endosmosis which
result from the u.-e of pure water.

Graham divided organic matters into two

ENDOSPERM.

[ 284 ]

ENOPLID^E.

classes : the crj-stalloid, or those which will
pass through a porous membrane, as soluble
salts ; the colloid, or those which will not,
as albuminous matters. This subject is of
special interest in regard to the nutrition
of animal and vegetable cells. For if their
walls are impervious to the so-called colloid
substances, a cell may be bathed with them,
and yet have to produce its own sarcodic
matter or protoplasm.

BiBL. Fischer, Fogg. Ann. xi. 126 ; Du-
trochet, Cycl. Anat. and Phi/s. ii. 98 ;
Works on Physics, as Buffj JExpe/-itn .-Fki/sik ;
Pouillet, Elem. d. Physique ; Peschel, Phy-
sics, &c. ; Graham, Proc. Pay. Soc. vii. 83 ;
Watts, Diet. (Dialysis) ; L'Hermite, Ann.
Sc. Nat. 4 ser. ii. 73; Nageli, Phys. Unters. ;
Hoppe-Seyler, Chim. Phys. 11 ; Rod well,
Diet. Sc. 162.

EN'DOSPERM. See Albumen, of
Plants.

EN'DOSPORE.— The name applied by
some authors to the inner coat of spores.
See Spose.

ENERTHENE'iAIA, Bowm.— A genus
of Myxoinycetes interesting from the fact
that the spores have been observed in situ ;
they are produced, five or sis together, in
globular sacs (asci) attached to the free
apices of the filaments of the capilHtium,
which arise from a disk at the top of the
percurrent stem (PI. 27. fig. 9). E.eleyans
was found by Bowman near Wrexham ;
and it has since been found in South Caro-
lina, and in Scotland.

In the clustered spores it resembles
Badhamia and some species of Peticularia
figured by Corda.

BiBL. Bowman, Linn. Tr. xvi. 151, pl.
16 ; Berk, and Broome, Ann. N. H. 1850,
V. 366, pl. 11. fig. 7.

ENHYDROSO'MA, Boeck.— A genus
of Copepodous Entomostraca.

E. curvatum, in dredgings, (Brady, Cope-
poda, Ray Soc. ii. 97.)

ENOP'LID^E, Duj.— A tribe of Nema-
toid Entozoa, distinguished by an oral or
pharyngeal armature, consisting either of
styles, hooks, or rods (bacilli). The mem-
bers are niicroscopic, and live in fresh or
sea- water, whence they sometimes find their
way into the alimentary canal of higher
animals. Genera :

Dorylai'7))Hs. Filiform, narrowed at the
ends ; mouth tubular, roti'actile, armed with
a single very long horny style; male Avilh
two equal, short, falciform spicules; fe-
male with the vulva in the middle of the

body, the uterus divided into two opposite
branches ; ova large, oblong.

D. stagnalis. In the intestines of the
carp and Ga4erosfetis. D. marinus ; marine.

Passalu'rus. I'usiform, elongate, nar-
rowed behind, with a subulate tail, or sud-
denly narrowed ; head obtuse : mouth with
three oblong pieces (jaws), united by a re-
sisting folded membrane ; oesophagus cla-
vate, succeeded by a broader stomach ; skin
transversely striate ; male with a single
spicule ; female with the vulva near the
stomach ; uterus and ovaries simple ; eggs
large, oblong.

P. ambiyuus. Large intestine of the
rabbit and hare.

Enop'his. Filiform, narrowed at the
ends, most behind ; head angular or trun-
cate, with a few opposite setae ; mouth with
three uncinate jaws ; oesophagus almost
cylindrical, cavity triquetrous ; tail ending
in a kind of sucker ; one or more red eye-
like spots on the oesophagus ; skin smooth ;
male with a supplementary orifice (anus or
sucker) in front of the genital orifice, and
with two equal curved spicules ; vulva near
the middle of the body ; uterus divided into

two opposite branches :

elliptical.

Marine and freshwater.

Oncholai'mns. Filiform, more or less
narrowed at the ends ; head obtuse ; buccal
cavity large, with two or three curved or
hooked jaws, placed lengthwise, at least one
with a prominent tooth ; oesophagus elon-
gate, nearly cylindrical ; no stomach ; tail
apparently terminated by a sucker ; skin
smooth. Male — tail suddenly narrowed,
short; spicules two, equal. Female — vulva
near, or slightly behind the middle ; uterus
two-branched ; eggs elliptic, large. Marine
and freshwater ; length 1-10".

Anyuil'hda (Phabdifis). Pharynx with
two or three longitudinal bacilli.

Atrac'tis. Mouth with two or three
jaws ; spicula two, unequah

Doubtful genera :

Amblyu'ra, Ehr. Filiform, mouth trim-
cate, with cirrhi ; tail subulate, slightly ex-
panded at the end, where there is a sucto-
rial papilla ; spicule single, retractile, with-
out a sheath. Probably species of Oncho-
lainius or Enoplus.

A. serpentulus= Vibrio s., Miiller. Found
in an old vegetable infusion.

A. gordius— Vibrio g., Miill. In marine
infusions.

Phanogle'ne. Filiform, pointed bejiind ;
mouth truncate, bilobed, with cirrhi, and

ENTEROBRYUS.

[ 285 ]

E^'TOMOSTRACA.

■v^itli red eye-spots behind the head; spicule
single.

P. luicans. Eye-spots contiguous; cirrhi
t-v\-o. In the intestine of the larva of a
neuroptercHis insect.

P. harbi(jer. Cirrhi four; red spots se-
parate. In stagnant -water.

EnchUid'htm. Filiform, a single red eye-
spot, as broad as the body, situate at some
distance fi-om the head. Marine.

See Anguilltjlid.^.

BiBL. Dujardiu, Helminth. pQ\ Jim A-
niaun, Lamarck's Anim. sans Vert. iii. 5G4 ;
Bastian, Linn. Tr. xxv. 73.

EXTEROBRY'US, Leidy.— A supposed
genus of Kiitzing's Leptomiteae, probably
the mycelium of some fungus, found in the
intestines of insects.

Eccei'na, Leidy, is another of these
forms.

BrBL. Leidy, Proc. y. H. Soc. Philadel.
1849, 225, Ann. N. H. 1850, v. 72 ; Robin,
Teget. Parns. 1853, 895, pi. 4. figs. 5, 6.

EXTERO'COLA, Van Ben.— A genus
of Copepodous Entomostraca.

JE. eruca, is found adhering to the intes-
tine of Ascidia int^stinalis. (Brady, Cope-
poda, Pay Soc. i. 147.)

ENTEROMORTHA, Link.— A genus of
Ulvaceee (Confervoid Algte), consisting of
freshwater and marine plants, with branch-
ed, tubular, green fronds, the walls of the
tubes being composed of a single flat layer
of polygonal cells. Reproduction by ciliated
zoospores, formed in considerable numbers
from the transformed contents of the cells
(PL 9. fig. 4). In this genus, Thuret states
that two foi'ms of zoospores occur, — one
large and four-ciliated ; the other, in fronds
with a yellower tint, smaller and with two
cilia; both kinds germinate. The zoospores
escape from the cells by a pore on the outer
surface (PI. 9. fig. 4 a) near the centre of
the cells ; and the latter persist for some
time in an empty condition. The marine
forms, of which nine species are described
by Harvey, are mostly from 1-2'" to several
lines in diameter, but many inches long.
JE. GrevUlei, Thuret {Uha Lactuca, Grev.,
Harv.), however, is thicker and saccate,
finally bursting. E. intestinalis, which
grows both in the sea and in brackish- and
freshwater ditches, often attains a length of
2 feet and more, and varies in thickness
from 1'" to 2-3".

BiBL. Harvey, Mar. Alg. 213, pi. 25 D,
Phyc. Brit. pls.^OS, 262, 282 ; Greville, Alg.
Brit. 179, Sc. Ci-ypt. Fl. t. 313, Eng. Bot.

21.37 Sc 2328; Thuret, Ann. Sc. Nat. 3 sdr.
xiv. 224, pi. 20. figs. 8-12 ; M4m. de Clier-
bourg, n. ; Rabenhorst, Fl. Alg. iii. 312.

ENTER0'PL1'L\, Ehr.— A genus of Ro-
tatoria, of the family Hydatinsea.

Char. Eye-spots none ; teeth absent; foot
forked.

E. hydatina (PL 43. fig. 27). Body co-
nical, hyaline ; foot small ; aquatic ; length
1-120".'

Probably the male of Hydatina.

BiBL. Ehrenb. Tnfus. p. 411.

ENTODIN'IUM, Stein.— A genus of Pe-
ritrichous Infusoria.

Char. Free, ovate, flattened; surface
smooth, indurated ; often with one or more
terminal spines. Three species ; in the ru-
men and reticulum of Ruminants.

BiBL. Stein, Lif. ii. 168; Kent, Inf.
653.

ENTOGO'NIA, Grev.— A genus of fossil
DiatomaceiB.

Char. Frustules in side view triangular,
containing a central triangular figure, having
a broad border divided by transverse costse
into punctate or cellulate compartments :
= species of Triceratium.

11 species. Barbadoes.

BiBi.. Greville, Qw. Mic. Jn. 1863, 235
(figs.).

EN'TOINIIS, Jones. — An estinct bivalved
Entomostracan, known by its oval, trans-
versely sulcate, and sometimes concentri-
cally wrinkled valves. The sulcus is nuchal
and much stronger than in some of the Oy-
pridiniform allies marked with this feature.
Silurian, Devonian, and Carboniferous.

BiBL. Jones, Mem. Geol. Surv. Edinh.
1861, 137 ; Ann. N. H. 1879, iv. 183.

ENTOMONETS, lL\xx.=Amnhiprora, pt.

ENTOMOSTE'GIA. — One of D-Qr-
bigny's orders of Foramiuifera, having the
chambers in two rows, alternate, coiled
into a spiral. This alternation of chambers,
however, in the coiled Foraminifera arises
from very different modes of growth, and
is not a group-character. It is due : — 1, to
bilateral asymmetry (Cassididina) ; 2, to
lateral elongation and intercalation of the
chambers in Pobertina (Bidimitia) ; 3, to
extreme alar division with interdigitatiou
of the chambers on .one {-Ace (Amphisfegi7ia);
4, to irregular growth of semi-auuular
chambers (Heferosfegina) ; and 5, to tent-
like cavities imder umbilical flaps (Asferige-
rina).

ENTOMOSTRACA.-A division of the
class Crustacea.

ENTOMOSTRACA.

[ 286 ]

ENTOMOSTRACA

Char. Free ; freshwater or marine ; body
more or less distinctly jointed, mostly con-
tained in a horny, leathery, or brittle shell
or carapace, formed of one or more pieces,
often bivalve ; branchife attached either to
the jaws or legs ; legs jointed, and more or
less ciliated ; development accompanied by
a regular moidting or change of shell, some-
times amounting to metamoi-phosis.

Many of the Entomostraca are very com-
mon in ponds, pools, and other collections
of water. When examined with the naked
eye, in a bottle or glass containing the water,
they appear as minute specks, generally in
active and often in jerking motion.

The shell is often beautifully transparent,
sometimes spotted with pigment, variously
striated, reticular, or notched, sometimes
spinous or tuberculated. It consists of chi-
tine impregnated with a variable amoimt
of carbonate of lime, which is sometimes so
great as to render it brittle, and to cause
copious effervescence on the addition of a
dilute acid ; and when boiled it turns red,
like the shell of a lobster. It varies in
structure, sometimes consisting of two
valves, united at the back, resembling the
bivalve shell of a mussel ; at others it is
simply folded at the back so as to appear
bivalve, without really being so ; or it con-
sists of a number of rings or segments. It
often presents a reticular appearance re-
sembling that of a ceU-structure.

The body itself, which is more or less in-
timately connected with the shell, is mostly
divided into numerous seg-ments. The head
is furnished with one or two pairs of an-
tennae ; the superior or anterior are usually
smallest, and in some genera easily over-
looked (PI. 20. fig. 28 a) ; sometimes one or
both of them are furnished in the male
with a hinge-joint, allowing considerable
flexure, so as to permit of its grasping the
female (PI. 20. tig. 8 a, of male; 9 a of fe-
nale) ; sometimes they are long, and pro-
vided with a tuft of filaments (PI. 20. tigs.
17, 18) ; at others they are simply long, and
filiform or setaceous (fig. 38). In some
Cypridinidse and Conchceciidse, the upper
antennae become organs of special sense
(smell or hearing), being clothed with
toothed club-shaped appendages, which
arise directly from the antennae (Cowc/io^cta),
or from its 'bristle-shaped appendages {Cy-
pndma). The inferior pair or posterior
antennae vary in size and structure like the
former, being sometimes large and branched
(fig. 28 b), and serving to row the animals

through the water, at others resembling
legs (tigs. 5, 17, &c.). In some genera they
are furnished with curious appendages,
effecting the purpose of the hinge-jointed
superior antennae. In some, again (Cythe-
ridse), the lower antennae (PL 19. fig. 37)
are annedwith alougcurved2- or3-jointed
urticating seta (b), connected at its base
by a duct with a vesicular gland situated
in the anterior part of the body (a). An
external stalked vesicle is also sometimes
found attached to this antenna.

The eyes are usually large, the pigment
black or red, and the muscles and the ner-
vous branches distributed to them fi-om the
cephalic ganglion very distinct.

A labrum or upper lip is often present,
compressed and terminated by a hairy lolje
(PI. 20. tig. 35) ; sometimes also a labium.
Behind these are situated two mandibles,
furnished with either blunt or pointed teeth,
often having a palpus or palp-tike organ
(tigs. 11, 20, 34). Next to these, comes a
pair of maxillae, jaws or foot-jaws (figs 12,
36), furnished with spines, hooks, or claws,
and sometimes branchiae (fig. 21). Behind
these is a second pair of foot-jaws (tigs. 13,
22). The legs are variable in number and
structure; they are often furnished with
flattened processes, fringed with beautifully
citiated or plumose filaments (figs. 30, 31,
32), thus exposing a large extent of surface
to the water, by which respiration is effec-
ted; hence they represent giUs, and are
called branchiae or branchial legs or feet ;
similar branchiae are often appended to the
foot-jaws ; and they are in constant motion,
even when the animal is at rest.

In some genera, as Canthocamptus, Cy-
clops, and Diapfonms, the respiration is ex-
clusively anal ; the water being drawn into
and expelled from the rectum at intervals,
as in many aquatic larvte of insects.

As the structure and arrangement of these
parts aflbrd characters for distinguishing
the genera &c., the details are given under
their respective names.

The abdomen is of variable length, join-
ted with a variously lobed post-abdomen,
often resembling a tail in a])pearance (figs.
3, 8) ; sometimes it is bilobed ; sometimes
furnished with a kind of spur near the end,
for supporting the ova within the shell.
Li some genera the external ovaries or ovi-
sacs containing the ova pass out between
two of the abdominal joints, yet remaining
attached, and gi^ ing a remarkable appear-
ance to the animals (figs. 9, 38). The in-

ENTOMOSTRACA.

[ 287 ]

ENTOMOSTRACA.

testiiial canal is usually straiplit or but
slightly curved ; sonietiiues, however, it is
coiled (fig. 7). The Entomostraca are
mostly herbivorous, although some are car-
nivorous. The sexes have not been distin-
guished in all the Eutomostraca, although in
some they are perfectly distinct. It appears
also that in certain of them, reproduction
takes place according to the law of alterna-
tion of generations — females only being
produced through several generations, and
the males appearing only at certain seasons.

The spermatozoa are often of most re-
markable structure (see Spermatozoa).
The ova are mostly rounded ; sometimes
tbev are covered with spines, and often
brilliantly coloured. They are either
hatched in the external ovaries mentioned
above, or in a space between the body of
the parent and the posterior part of the
shell ; or they are deposited in massi>s upon
and glued to water-plants, and hatched in-
dependently of the parents.

At particular seasons of the year, the ova
in certain species are furnished with thick
capsules, and imbedded in a dark opaque
substance presenting a minutely cellidar
appearance, and occupying the above-men-
tioned interspace between the body of the
animal and the back of the shell (fig. 37 a).
This is called the ephippium, and the ova
ephippial or winter ova (Eggs).

"\\ hen first hatched, the young (fig. 16)
difier very strikingly in form and structure
from the adults (figs'. 8, 9).

The larval forms of the higher Crustacea
often bear considerable resemblance to the
perfect Entomostraca.

The minute structure of the Entomostraca
is difficult to determine ; for although the
bodv and shell are frequently comparatively
transparent, the parts are exceedingly deli-
cate and soft, so that they are easily crushed
and mutilated,and their appearance distorted.

The Entomostraca are best preserved in
solution of chloride of calcium or glycerine
(see Preservation). Some use glyceriue-

jelly.

A large number of Entomostraca are
found fossil ; among which must be specially
mentioned the Trilobites, of which 1600
species are described.

The following systematic arrangement
comprises the most common genera and
species. Numerous others are described,
Brady enumerating 67 genera of the Cope-
poda'ouly: these are briefly mentioned mi-
der the individual heads.

lyegion 1. Lophyropoda. Branchi.ie at-
tached to the organs of the mouth ; leg8
few, not exceeding five pairs, serving for
locomotion, articulation mostly more or
less cylindrical ; anteunie two pairs, one
pair used as organs of motion.

Order 1. Ostracoda. Shell consisting of
2 valves, entirely enclosing the body ;
feet 1-3 pairs, adapted for progression ;
no external ovary.

Sect. 1. PoDocoPA. Inferior antennae sim-
ple, subpediform, geniculate, clawed
at the end. (Includes all the fresh-
water and most of the marine Ostra-
coda.)

Fam, 1. Cyprid^. Superior antennoe
mostly 7-jointed, with a dense brush
of long setae ; eye usually single ; feet
2 pairs, the last bent up between the
valves ; abdominal rami 2, elongate,
clawed at end.
Gen. : Cypris (PL 20. figs. 5 & 19), Can-
dona^ Cypridopsis, Pai-acypris, Ac/Iaia,
Notodromas, Fonto(ypris, Argiiloecia,
Bairdia, Macrocypris, and Chlamydo-
theca.

Earn. 2. Cytherid^. Superior antennae
5-7 -jointed, setigerous or spinous; in-
ferior 4-6-jointed, without a brush;
feet 3 pairs, ambulatory ; post-abdo-
men rudimeutaiy, consisting of 2 very
small lobes. (Comprises most of the
marine species, and almost all the nu-
merous fossil species.)
Gen. : Cyfhere (PI. 20. tig. 2Q), Limnon/-
there, Cytheridea., Eucythere, Ilyobates,
Liixoconcha, Xestoleheris, Cytheriira,
Cytlieropteron^ Bythocy there, Cythe-
rideis, Sderochilus, and Paradoxo-
stoma.

Sect. 2. Myodocopa. Inferior antennae
2-branched : one branch rudimentary,
the other powerful, many-jointed, with
long natatory setae ; mandibular palp
very large, subpediform, geniculate, not
branchial. Post-abdomen with 2 broad
plates, clawed.

Earn. 3. Cytrldinidje. Feet 1 pair; ver-
miform, annulated, long; mandibles
obsolete ; second pair of jaws with a
large branchial plate ; eyes, 2 com-
pound, 1 simple.
Gen. : Cypn'dhin, Asferope, Btadyn'nefus
{Eurypjyius), Fhilomedes, Cylindrole-

ENTOMOSTRACA.

[ 288 ]

ENTOMOSTRACA.

beris {CyprideUa, Cyprella, Entomis?,
fossil) .

Fam. 4. Entomoconchid^.

Gen. : Heterodesmus, Entomoconchus.

Fam. 5. Conchceciid^. Feet 2 pairs,
posterior rudimentary; mandibles di-
stinct ; eyes none.
Gen. : Conchoscia, Halocypris.

Sect. 3. Cladocopa. Inferior antennae
2-branclied, both branches well deve-
loped, natatory ; upper antennpe nata-
tory, not geniculate, with a lash of long
setae ; mandibles distinct, palp short ;
2 pairs of thoracic appendages — ante-
rior large, natatory, posterior membra-
naceous and branchial.

Fam. 6. Polycopidje. Char. Those of
the section.
Gen. : Polycope.

Sect. 4. Platycopa. Lower antennae 2-
branched, flattened ; branches few-
jointed, with numerous setae. Supe-
rior antennae strong, geniculate, shortly
spiniferous ; mandibles small, palp
large ; 3 pairs of thoracic append-
ages, all maxillifoi-m ; first and second
pairs of jaws with a large branchial
plate.

Fam. 7. Cytherellidje.
Gen. Cytherella.

Order 2. Copepoda. Shell jointed, forming
a buclder, enclosing the head and thorax ;
legs five pairs, mostly adapted for swim-
ming ; ovary external.

Fam. 1. Cyclopid^. Head consolidated
with the thorax; foot-jaws two pairs,
generally small ; fifth pair of legs rudi-
mentary ; eye single ; both superior
(larger) antennae in the male furnished
with a swollen hinge joint.

Cyclops. Foot-jaws large and strong,
branched; ovaries double (PI. 20. figs.
8,9).

Canthocamptus. Foot-jaws small, sim-
ple ; ovary single (PI. 20. fig. (>);

Arpactims. Foot-jaws stout, terminated
by a claw ; ovary single.

Alif.utha. Foot-jaws small, simple ; body
flat ; a strong falciform appendage to
the fifth segment of the body on each
side (PI. 19. fig. 3).

Tachidius, Dactylopus, Delavalha.

Fam 2. Diaptomid^. Head consolidated
with the first j oint of thorax ; foot-jaws
three pairs, well developed ; last pair
of legs differing in structure from the
others, and differing from each other in
the two sexes ; eye single, sometimes
pedunculated in the male ; right an-
tenna only with the swollen hinge-
joint in the male.

Eiaptomus. Cephalothorax and abdo-
men each of five segments (PI. 20.
fig. 38).

Temora. Cephalothorax of five, abdo-
men of three segments.

Anomahcera. Cephalothorax of seven,
abdomen of four- segments (PI. 19.
fig. 6).

Dias.

Fam. 3. Cetochilid^. Head consolidated
with first joint of thorax; foot-jaws
three pairs, strongly developed ; eves
two ; right antenna only with the
hinge-joint in the male.

Cetochihis (PL 19. fig. 21).

Notodelphys, Provisionally (PI. 19. fig.
22).

Legion 2. Branchiopoda. Branchiae at-
tached to the legs ; legs from four to sixty
pairs.

Order 1. Phyllopoda. Legs from eleven to
sixty pairs in number, joints foliaceous
and branchiiform, chiefly adapted for re-
spiration and not motion ; eyes two or
three, sometimes pedimculated ; antennae
one or two pairs, neither adapted for
swimming.

Fam. 1. Branchipodida. Body not en-
closed in a carapace or shell ; antennae
two pairs, the inferior horn-like, and
with prehensile appendages in the
male ; legs eleven pairs.

Arteniia. Tail simply bilobed; no ap-
pendages at the base of the cephalic
horns.

Bramhtpus. Tail formed of two plates,
cephaHc horns with fan-shaped appen-
dages at the base (PI. 20. fig. 3).

Fam. 2. Aspidophora. Body enclosed in
a shell ; antennas one or t^Ao pairs ;
legs more than eleven pairs.

Ajms. Shell flat, bucliler-like ; antennae
one pair, small ; ej-es sessile.

Nebalia. Shell folded at the back ; an-

ENTOMOSTRACA.

[ 289 ]

ENTOMOSTRACA.

tenure two pairs, large ; eyes stalked
(n. 19. %. 26).

Fani. 3. DiTmiirDA. Bivalve.
Lininadia, Estheria, Limnetis,

Order 2. Cladocera. Legs four to six pairs,
cliietiy branchial ; eye single, and very
large ; antennte two pairs, inferior large,
branched and adapted for swimming.

Fam. 1. Daphniad.e. Superior antennae
small ; inferior large, two-branched ;
legs live or six pairs, all enclosed within
the carapace; eye single, large.

* (Daphnina.) Legs five pairs ; inferior
auteunaj two-branched, one branch f oui-, the
other three-jointed.

Daphnia. Head produced below into
a beak ; superior autenuaj very small
(PI. 20. fig. 26).

Moina. Head rounded and obtuse ; su-
perior antennae large (PI. 19. tig. 20).

Macrothrix. Head beaked, beak di-
rected forwards ; superior antennae
one-jointed, hanging from the beak
(PI. 19. fig. 25).

Bosmina. Head terminating in a sharp
dii'ect beak ; superior antennae long,
mauv-iointed, projecting from end of
beali (PI. 20. fig. 2).

Drepmiothrix, Lathonura, Acantholehei'is,
Ilyocryptus.

** (Sidina.) Legs six pairs ; inferior an-
tennae two-branched ; a row of spines arising
from the edge of larger branch ; superior
antennae of moderate size.

Sida. One branch of inferior antennae
three-, the other two-iointed (PI. 19.
fig. 27).

Daphnellu. Both branches two-iointed
(PI. 20. fig. 27).

Fam. 2. Polypheshd^. Inferior antennae
two-branched, one branch four-, the
other three-jointed; lower part of shell
forming a large vacant space for con-
taining the ova and young ; eye very
large ; legs four paii's, not contained
within the shell.

Polyphemus. Tail-like abdomen project-
ing outside the shell : freshwater (PI.
19.' fig. 29).

Evadne. Abdomen scarcely projecting
from the shell ; marine (PI. 19. fig. 30).

Fam. 3. LYNCEiD.ii;. Superior antennas
very short; inferior of moderate size,
branched, each branch three-jointed;
legs five pairs ; eye single, with a black
spot in front ; intestine convoluted,
having one complete turn and a half.
Eurycercits. Shell subquadrangular, ab-
domen forming a fiat, densely serrated
plate (PI. 20. fig. 39).
Chydorus. Nearly spherical ; beak very
long, sharp, and curved ; inferior an-
tennas very short (PI. 20. fig. 7).
Camptocercus. Ovoid ; abdomen long,
slender, and very flexible, serrated (PI,
20. tig. 4).
Acropenis. Somewhat harp-shaped, with
an anterior inferior obtuse angle ; infe-
rior antennae rather long (PI. 19. tigs.
1,2).
Alonn. Quadrangular, striated or grooved
longitudinally ; inferior antennae short
(PI. 19. tigs. 4, 5).
Plewoxas. Giblaous above and anterior-
ly ; obliquely truncate below ; first pair
of legs very large (PI. 19. fig. 32).
Peracantlm. Oval, lower end with a
curved posterior point, fringed infe-
riorly and antero-superiorly with strong
hooked spines (PI. 19. fig. 31).
Monospilus.

See Crustacea and Siphonostoma.
BiBL. Baird, Br. Entom. ; M. -Edwards,
Cnistac. iii. ; Straus, Mem. Mits. 1819, v.
380, and 1821, vii. 33; Koch, Beutsclil.
Crustac. ; Desmarest, Crustac. ; Jones, En-
tom. Cretac. Form. {Palceont. Sac); Entom.
Tert., and Foss. Edherice ; Zencker, Miiller^s
Archiv, 1851 {Micr. Tr. i. 273) ; Morris,
Brit. Foss. 98 ; Lubbock, Linn. Tr. xxiii.
176, and xxiv. 197 ; Dana, Classif. Crust.
1853, Report on Crust. U. S. Exped. 1855 ;
Baird, A^in. N. Hist. 1862, ix. 132, and x. 1;
Grube, Esth. m. Limnad., Archiv Nat. xxxi.
1865 ; Plateau, Ann. iV. H. 1869, iii. 12 ;
Schcedler, Cladocera (3 pi.), 1863; Brady,
Ann. N. H. 1864, xiii. 59 {New Ostracoda) ;
1868, ii. (Ostr. from Scandinavian Seas,
Mauritius, c^'c); 1869, iii. 45; lA.. Linn. Tr.
1868, xxvi. 353 (Monoyr. Ostracoda) ; and
Copepoda {Ray Soc.) ; Norman and Brady,
Monogr. 1867; Sars, Orersiyt af Norges
Mar. Ostrac. 1865 ;^ Lilljeborg, De Crusta-
ceis, 1853; Zencker, Mull. Arch. 1850 {Cy-
pris) ; ibid. 1851 ; id. Arch. Naturg. 1854 ;
Hartog, J7i. Mic. S. 1880, 243 ; Brady and
Robertson, Ann. N. H. 1872, ix. 48 ; & Tr.
Palceontog. Soc. xxviii. ; Clans, Copepoda,
1881 ; and the BiBi.. of the genera.

V

ENTOPIIYSALIS.

[ 290 ]

ENTOZOA.

ENTOPHY'SALIS, KLitz.— A genus of
Palniellacepe (Confervoid Alppe).

Char. Frond globose, cartilaginous, con-
taining numerous more or less confluent
families of minute oblong cells.

E. f/rannlosa. On mariue rocks. Dalmatia.

BiBL. Kiitziiig, r/i;/c. Gen. 177, pi. 18;
Piabenhorst, A/g. iii. 43 (fig.).

EN'TOPHYTES.— A general term ap-
plied to parasitic plants (chiefly Fungi),
growing in the interior of animal or vege-
table structures. See Pabasites, vkge-

TABLE.

ENTOP'YLA, Ehr.— A genus of Diato-
macete.

Char. Frustules prismatic, compressed,
compound, arcuate ; the two end valves
transversely striated, not alike, one of
them being convex outwards, the other
concave, and with a large pore (?) at each end.

E. australis. Valves linear, rounded at
each end, with more than forty transverse
costse, traversed by a longitudinal flexuous
line ; inner plates in the adult state sixteen,
in the young state only three ; marine, and
found in guano ; length l-240"_, in the young
state 1-720" and with only six costfe be-
tween the pores.

BiBL. Ehr. JScrl. Ber. 1848, G ; Ann. N.
Hid. 1848, i. 393.

ENTOSI'PHON, Stein, = Anisoncma, Duj.,
pt.

ENTOSOLE'NIA, Ehrenb.— A Laf/em
is said to be Eutosolenian if it has its
neck, or stolon-tube, growing inw^ards (in-
"troverted). This was once thought to be
a generic character ; but it occurs in Poh/-
morpMna, and is not even of specific value.

Entosolenia (Lat/eiut) ylohosa, PI. 23.
fig. 23, a, h, is a very common form^ recent
and fossil.

BiBL. Carpenter, Introd. Foram. 1.57.

Fig. 107.

Entosthodon Templetoni.
Fragment of the peristome. Magnifled 100 diameters.
]':NTC)S'TII()1)()N, Schwagr.— a genus
of Fuuariacea) (Acrocarpous Mosses), inclu-

ding some of the Gymnostoma and Weissice
of authors.

BiBL. Wilson, Bryol. Brit,. 272 ; Berke-
ley, Ilandh. 175.

"EN'TOTHIIIX, Kiitz.— A genus of Os-
cillatoriacese (Confervoid AlgiB).

Char. Frond tubular, composed of nu-
merous very slender filaments, densely
twisted into a cord, and enclosed in a la-
mellar sheath.

E. funicidnris. Filaments continuous,
brownish, flexuous. In long-kept water.

BiBL. Kiitzing, Phyc. Gen. 224, pi. 6.
fig. 8 ; Ptabenhorst, Fl. Akj. ii. 160 (fig.).

ENTOZO'xV.— A class of Vermes ; con-
taining the intestinal worms, &c.

The Entozoa are animals mostly residing
parasitically, during either the whole or a
part of their lives, in the cavities or in the
substance of the organs of other animals ;
they are very generally met witli through-
out the Animal Kingdom ; and they derive
their nourishment from the liquids of those
animals of which they constitute the para-
sites. Their form is mostly elongate, and
the body more or less distinctly jointed.

The integument consists of a delicate ho-
mogeneous epidermis, often thrown into
transverse folds ; sometimes also into longi-
tudinal folds, giving the body a winged
appearance. In some species it is furnished
with papillre, spines, or horny reflexed
prickles, either scattered over the greater
part of the surface or confined to the ante-
rior extremity' of the body, in the latter
case serving as organs of adhesion. Beneath
the epidermis is the cutis, intimately fu.^ed
with or almost entirely consisting of layers
of transverse, longitudinal, and oblique flat-
tened fusiform muscular fibres, resembling
the organic or unstriped muscular fibres of
the Vertebrata. ■

Beneath or in the substance of the skin,
in the Cestoid Entozoa, are numerous mi-
nute oval or rounded bodies, containing
carbonate and phosphate of lime; these are
regarded as forming the rudiments of a
cutaneous skeleton, and they possess a con-
centric laminated structure.

The form and structure of the head and
its apppcndages, in the shape of hooks, suck-
ersj etc., are described with the genera and
species, as their form and arrangement are
used as generic characters.

The nervous system of the Entozoa is not
well known. In the cystic or larval forms,
none has- been detected. In the Cestoids
and Acanthocephala, it consists of a single

ENTOZOA.

[ 201 ]

ENTOZOA.

cephalic rranfjlion, sondin;i- off branch(>s to
the proboscis. In the Treinatoda, of two
cesophag-eal ganglia, connected by a trans-
verse cord, and sending ofl" two lateral
branches, which traverse the body longitu-
dinally. In the Nematoidea, it is composed
of a single longitndinal cord, furnished at
its origin and termination with a ganglion.

Organs of special sense appear to be
absent in the Entozoa, excluding that of
touch, which resides in the various cephalic
appi'udages. In some, especially in the
ciliated embi'yonic form, there are red or
black cervical spots, which have been re-
garded as eyes ; but they do not appear to
contain any refracting body comparable to
a lens. Helminthologists have diffi^red as
to the presence of a digestive, circulating,
and water-vessel system in the Cestoidea
and Acanthocephala, certain tubes found in
them being regarded as belonging to each
of these svstoms bv different authors ; the

longitudinal vessel-like
branches terminatins: in

tubes with lateral

a caudal pore, are
however, now regarded as excretory organs.
In most of the remaining Entozoa, the
digestive apparatus is well developed, the
mouth distinct, the posterior portion of
the alimentary tube much ramified, and
terminating either in a cnecal extremity
or in a distinct anus. Remarks upon
these systems will be found under the
genera.

Propagation. — The Entozoa are propa-
gated by spoutaneons division, by gemma-
tion or the formation of gemmae, and by
sexual organs ; and they illustrate the law
of alternation of generations.

The spontaneous division, which is al-
ways ti'ansverse, differs from that of the
Infusoria and Zooph\^es, in the new indivi-
duals produced not being perfect — a certain
numbar of organs only being reproduced,
as in the joints (proglottides) of the body
of the Cestoidea.

The formation of gemma? occurs in the
larval or cystic forms of Tcenia — Coenurus
and Echinococcus.

In those Entozoa which are propagated
by sexes, the individuals are either herma-
phrodite or unisexual. In the Cestoidea the
sexual organs are usually repeated in each
joint, except those near the head. And it
appears that there are two Irinds of ovaries
— one for the production of the germ (the
germinal vesicle and spot), and the other
for the yolk. In addition to which, there
■ is mostly a uterus, vagina, testis, penis (spi-

culum), and vesicula sominalis. TIk." ova
are round or oval, often furnislied with a
shell, which sometimes has a lid.

The development of tlie ova of the En-
tozoa takes place according to two methods:
either the yolk-mass undergoes the ordi-
nary process of segmentation, idtimately
forming the embryo ; or large transparent
embryoiial cells form in the J'olk, the
latter not becoming segmented, but under-
going subdivision and diminution in size,
the growth of the embryonal cells con-
tinuing at the expense of the yollf-ma=3
until it is entirely consumed ; the entire
mass then becomes covered with a delicate,
sometimes ciliated, epithelium, and forms the
embi'yo.

In numerous instances, after this primary
stage of development — the embryonal-cell
condition — has been attained, the embryo
does not become directly developed into a
form of being resembling the parent ; but
the intermediate larval or nurse forms, de-
scribed under Ctkxerations, Alternation
OF, are produced from it by a non-sexual
process ; and ultimately, forming the last
stage of the metamorphosis, beings resem-
bling the parent, and furnished with sexual
organs, are produced. The discovery of
the alternation of generations has brought
to light the fact that many of the supposed
species of Entozoa are only the larval or
nurse forms of the true species ; and that
many of these forms only complete their
stages of metamorphosis when placed under
particular circumstances, i. e. in the bodies
of different animals, or in different organs
of the same animal.

The foUov.ing arrangement may serve as
an index to the articles upon the Entozoa,
contained in this work :—

Order 1. Sterelmintha. Alimentary canal
often absent, or not distinct ; wlien pre-
sent, with a single orifice only, and
branched.

Earn. 1. Cestoidea (tape-worms). Body
strap-shaded,' distinctly or indistinctly
divided into transverse joints; male
and female organs in each joint ; ali-
mentary canal indistinct or none.

Bnthrioccphalns, Tcenia.

(Ci/dica) Nm-se or larval forms of
Cestoidea : —

Cysticercus, Coenurus, Echinococcus.

Earn. 2. Trematoda. Body mostly flat-
tened ; alimentary canal distinct,

u2

EOSINE.

[ 292 ] EPENDYMA YENTEICULORUM.

branched ; male and female organs in
each individual.

Ainphistuma, DipJozoon (Diporpa),
Distoma {Cercarin), Gyrodactijlus.

Earn. 3. Acanthocephala. Body flat-
tened, transversely "wrinkled, becoming
cylindrically distended by the imbibi-
tion of water ; sexual organs in separate
individuals.

Ech in orhyn ch us.

Order 2. Coelelmintha. Alimentary canal
present, distinct, simple, with two oritices.

Earn. 4. Nematoidea (roiuid worms). Body
cylindrical, hollow ; sexes separate.

Trichocephalus, l''{layia,Ascaris{ Oxy-
urus), AngiiUhda, Trichina, Anchyh-
stoma, Dochmius.

See AcEPHALocYSTS and E^TOPLIT)^.
BiBL. Siebold, Vergl. An. ; Eudolphi,
Enfoz. Hist. Nat. and Entoz. Si/n. ; Dujardin,
Hchninth. ; Bremser, Icones Hehninth. ;
Owen, Todd''s Cyci.\i.l\\; Blanchard, ^;^?^.
Sc. Nat. 3 ser. Zool. vii. viii. x. xi. xii. ;
Diesing, Helminth. ; Vogt, Zool. Briefe ;
Beneden, Vers cesto'i'des, 1850 ; id., Vers in-
testin. (27 pL), and Icon. d. Hehn. 18G0;
Pagenstecher, Trevudod-Larvcn ; Kiichen-
meister, Farasiten, 1881 ; Cobbold, Para-
sites; Ebertli, Nematoden, 18G3 ; Schneider,
Nematoden (22 pi., 130 cuts), 1860 ; Pa-
vaine, Entozoaires, 1877 ; Linstow, Hehnin-
thol. 1878; Wagener, Cestodcn (22 pi.) ;
Leuckart, Menschl. Parasit. 1881.

EO'SINE. — A beautiful rosy dye, having
the composition of tetiabromo-lluorescine,
produced by the action of bromine upon
nuorescine dissolved in acetic acid. It is a
ra])id staining agent, dyeing the protojilasm
of nucleated blood-corpuscles, but not the
nuclei ; it is also useful in the distinction of
nerve-structures.

BiBL. Gibbes, Hist.; Dreschfeld, Jn. Anat.
xi.; Watts, IHct.Chem.; W'issozky, Schultze's
Arch. 1877, xiii. 479.

EOS'PHORA, Ehr.— A genus of llota-
toria, of the family Hydatiufea.

Char. Eyes three, sessile — two frontal,
one cervical ; foot forked. Ereshwater.
Among Confervcs.

There are three species.

E. dif/itafa (PI. 4:5. fig. 28 : fig. 29, teeth).
Body conical, liyaliiie, not aiiricled, toes

one third of the foot in length.
l-'JG".

BiBX,. Ehr. Infits. p^ 451.

Length

EOZO'ON,Dawson.— AEoraniinifer,with
hyaline and tubular shell-structure, and
very numerous irregiUai' chambers. Out-
spread for about a square foot, and hea;ped
up nearly half as high, with diminishmg
size, it occurs imbedded in the Lauren-
tian and other old limestones of Canada,
Bohemia, &c. The chambers, stolons,
pseudopodial passages, and canal-system are
represented by delicate casts of magnesiau
silicates, such as pyroxene, serpentine, and
loganite ; sometimes by calcite, Uke that of
the shell itself. In the former case they
can be separated by the removal of the cal-
careous shell in slices of the marble, by
dilute acid.

Layer after layer of Eozoon formed banks,
thus constituting a large proportion of the
massive limestones ; and the sarcode was
mostly replaced by hydrous silicates, such
as have been injected into the pores of Si-
liu'iau and other fossils, and just as glauco-
nite takes the place of the soft parts of
Eoraminifera, Polyzoa, &c. in existing
seas. The Eozoonal limestone, with , its
associated muds, sands, and shingle, has
been folded, crushed, and variously meta-
morphosed, often in a high degree.

BiBL. Logan, Dawson, Carpenter, and
Hunt, Quart. Jn. Geol. Sac. 18G5, xxi. 45,
and 18G7, xxiii. 257 ; Carpenter, Intel.
Ohserv. 18Go, vii. 278: and Microscope, 1881;
Giimbel, Sitz. layer. Akad. 186G ; Zirkel,
Mineralien, 1873 ; Mcebius, Eoz. Can. 1878 ;
King and Eowney (disputing the organic
character of Eozoon), Proc. Pay. Irish
Acad. ser. 1. x. and ser. 2. i. ; & An Old
Chapter ^-c. 1881.

EPEIRA, Walck.— A genus of Arach-
nida, of the order Araneidea.

E. diadema (the common autumnal gar-
den-spider) forms a favomable object for
the examination of the various structural
pecidiarities of spiders, — as the integument
(PL G. fig. 4) ; the legs, with their hairs and
claws (fig. 8, a, b) ; the toothed hairs at
the end of the feet (fig. 8) show very clearly
the transition from the hairs to the claws,
in fact, that the latter are mere modifica-
tions of the former ; also the lung-plates
(figs. 9, 9 b) ; the spinnerets, the web (fig.
11), &c.

BiBL. Walckenaer, Apteres ; Brandt,
Medizin. Zool. ; Walker, Brit. Sjrid. {Pay
Soc).

EPEN'DYMA YENTEICULORUM is

EPHEBE.

[ 293 ]

EPHEMI^.RID.E.

the name griven to a layer whioli eoats
those portions of the ventiieles of the braiu
which are not connected \vith the prolonga-
tions of the pia mater — as the floor of the
fourth ventricle, the ar|neduct of Sylvius, the
floor and the sides of the third ventricle,
the fifth ventricle, with the roof, the ante-
rior and postin'ior cornua, and a considerable
part of the inferior cornua of the lateral
ventricles. It consists of deUcate ciliated (?)
pavement epithelium, situated either imme-
diately upon the cerebral substance, or npon
an intermediate layer of connective tissue, or
of a soft homogeneous or granular mass. The
Cells are nucteated, and vary in diameter
from 1-900 to 1-490" ; they sometimes eon-
tain pigment.

The ependyma is considered by many
anatomists a portion of the arachnoid
membrane. Corpora amrjlacea are often
met with beneath it ; sometimes also brain-
sand.

BiBL. KoUiker, Mikr. Anat.

EPHE'BE, Fr.— A genus of Collema-
ceous Lichens, usually described in an imper-
fect state as species of Stiyonema, a supposed
genus of AlgjB. E. ptihescens has a hairy,
branched, cartilaginous frond, covering the
sm-face of damp sub;ilpiue rocks with a
blackish-brown felt ; tlie branches are subu-
late, and the plant is dicBcious ; some speci-
mens have the branches swoUen into spindle-
shaped receptacles, in which are imbedded
numerous conceptacks, opening by a pore,
lined with clavate theccs, each containing
eight unisepate sjwres ; other specimens
bear spherical or subovoid subapical j)?/c?< idia,
in which are immersed spermogonia, de-
Msciug by a pore, containing numerous
linear basidia (sterigmata), supporting very
slender oblong spertnntia. Two supposed
species of Stigonema, Ag. (atrovirens and
??iammilIosiim). have been foimd in fruit as
perfect Epjhebce, by Thwaites. According
to Flotow, forms of this Lichen have been
described under many names by Kiitzing
and others.

BiBL. Bornet, Ann. Sci. Naf. 3
ser. xviii. 15.3, pi. 7 ; Berk, and
Br. ^/»?. N. H. 1851, vii. 188 ;
Nvlander, Syn. pi. 2. figs. 1 & 7 ;
Leishton, Lich. Fl. G. B. 10.

EPHELO'TA, Wright.— A
genus of marine Infusoria, fam.
Actinophryina (Acinetina, Clap.
and Lachm.), resembling Podo-
phrya, but the tentacles pointed
instead of capitate, and forming a
wreath or circlet.

2 species. On Serfidaria, and in the
mouths of shells containing hermit-crabs.

BiBL. Pritchard, Inf. p. 662; Wright,
Ed. New Phil Jn. 1858, p. 7.

EPIIEM'ERA, Linn.— A genus of Neu-
ropterous Insects, of the family Ephemeridae.

Char. Wings four ; posterior filaments
three ; head of larva with cornua.

The larva and pupa are favourite micro-
scopic objects, for showing the dorsal vessel,
the circulation, branchial plates, &c. See
Ephemerit)^.

EPlIEME'REzE.— A family of inoper-
culate Acrocarpous (terminal-fruited) Mos-
ses, usuallj' dwarf, caespitose, or gregarious.
Stem almost simple. Leaves more or less
oval or lanceolate, slightly concave, pellucid,
with or without nerves. Cells of the leaves
parenchymatous, lax in all parts, elongate,
not papillose. Capsule mostly obliquely
apiculated.

British Genus.

Ephcmencm. Calyptra campanulate. In-
florescence monoecious or dioecious (anthe-
ridia on a very short special brcanch situated
near the base of the stem).

EPHEMERTD.E(May-flies).— Afamily
of Neuropterous Insects.

Characterized by the minute size of the
antennfe ; the unequal size of the anterior
and posterior pairs of wings (the latter of
which are in some absent) ; the membra-
nous and almost obsolete mouth ; and the
elongated j ointed setfe at the posterior end
of tlie body.

Body long, slender, and soft ; head small,
ti-ansverse-trigonate ; eyes large, nearly oval,
lateral ; ocelli three, forming a triangle be-
tween the eyes ; antennie three-jointed, the
two basal joints thick, the third forming a
long slender seta. Abdomen consisting of
nine joints; the terminal the longest, and
gradually narrowed and furnished at the
apex in both sexes with two or three long,
slender, many-jointed filaments. Legs
slender ; anterior pair in the males pon-ected,
much elongated, with the tibiae and tarsi

Fig. 198,

Ephemera Swammerdamii. Nat. size.

EPHEMERID^.

[ 294 ]

EPIDERMIS.

appearing soldered together ; basal tarsal
joint very miuiite, tarsi tive-joiuted, termi-
nated in the fore legs of the male by two
oval pulvilli ; in the four posterior legs tarsi
short, hve-joiuted, and terminated by a large
oval pulvillus, and a single broad notched
claw.

These insects must have been seen by
every one, rising and falling on the wing,
near the banks of rivers-and pools; in the
perfect state their life lasts but a few hours,
whence the name. The ova are deposited
in the water. The larva bears a considerable
resemblance to the pupa, from which it
diifers in the absence of rudimentary wing-
covers ; they are frequently mistaken for
each other.

The pupa of the common Uphemera (vid-
gata) (PL oo. fig. lo) has the prothorax as
broad as the head, transverse-quadrate ; the
mesothorax gibbous ; the head rather small,
with two short horns in front, and two horny
toothed mandibles, furnished at their upper
angles with a long curved horn ; labrum
flat, membranous, ciliated, and with the
angles rounded ; maxillte small, membra-
nous, curved, pointed at the tip, and inter-
nally setose ; maxillary palpi four-jointed,
and not extending beyond the front of the
head ; labium large, membranous, four-lobed,
and furnished with a broad tongue ; labial
palpi broad and three-ji anted; antennae
about twice the length of the head, many-
jointed and ciliated ; legs short, broad, and
much compressed ; tarsi two-jointed, with a
terminal hook ; abdomen nine-jointed, the
six basal segments being furnished on each
side with a pair of elongated, rather narrow,
gills or branchial plates {a), with long, nar-
row filaments at their edges, through each
of which a trachea extends to the tip, the
trachefe from each contiguous pair of fila-
ments uniting near the base, and then
running to the large tube which traverses
the centre of each plate ; there are in all
24 branchial plates. At the end of the
abdomen are three elegantly feathery sette.

The pu})a of Claoii — another of the
Ephemeridic, in which the imago has two
wings and two abdominal setfe — resembles
that of Ephemera, but has the antenna3 as
long as the body.

The larva3 and pupre of the Ephemeridfe
may be most easily caught in the ring-net,
and are admirably adapted for showing the
dorsal vessel, with its valves, and the circu-
lation. They are perhaps best preserved in
glycerine, or solution of chloride of calcium.

BiBL. Westwood, Introd. ; Pictet, Lis.
Nevropt., 1843; Curtis, Brit. Entnm. 70S;
Pritchard, Micr. lllustr. Gl (pi. 2. fig. of
C'lceon pupa).

EPHEM'ERUM, Ilampe.— A genus of
Ephemere8e( Acrocarpous Mosses),including
part of Phasciim of authors.

EiBL. AVilson, Bryol. Brit. 27; Berkeley,
Brit. Mosses, 304.

EPIIIP'PIA.— The winter-ova of the
Entomostraca. See Eggs and Entomos-

TEACA.

EPIBLE'MA, See the Epidermis of
Plants.

EPICLIN'TES, Stein.— a genus of Hy-
potrichous Infusoria, fam. Oxytrichina.
(Stein, //(/. ii. ; Kent, Itif.^

EPICOC'CUM, Lk.— Agenus of Stilba-
cei (Ilyphomycetous Fungi), parasitic upon
dead leaves, &c., consisting of very minute
gregarious tubercles, somewhat linearly
arranged, reddish or purplish, containing
numerous spherical, smooth or roughish,
reticulate spores. JS. nef/lectian is adnate
to a short pedicel. When mature the
stroma is quite covered with spores about
1-2000" in diameter. Uredo Bqui^eti,
' Br. Flora,' is an Epicocciun with smooth
spores.

One species of Epicoccum, which grows
on decaying vegetable matter, produces a
form of what is commonly called Blood-
rain. It was developed on the calico cm--
tains of a shower-bath during the preva-
lence of choleiti in 1834, and excited some
consternation, as it was supposed to be
connected with the malady. It occm-red a
short time afterwards in considerable abun-
dance on a water-melon.

BiBL. Desmaz. Aim. Sci. Nat. 2 ser. xvii.
9o ; Berk, and Broome, Ann. N. II. 18o0,
V. 466, Crypt. But. 312 ; Fries, Summa Veg.
476.

EPIUER'MIS OF Animals. See Skin.

EPIDERMIS OF Plants.— There are
few parts of the structure of vegetables that
have given rise to more discussion than the
epidermal cells and the tissue they consti-
tute. Even the term epidermis has become
to a certain extent equivocal, since it is
used by some authors in the sense in which
cuticle is used by others, and vice versa. Our
object here will be to state as briefly as
pos.'-ible the most remarkable facts, and the
explanations which are received by the best
authorities.

If we gently scrape the surface of the
leaf of a hyacinth, or other soft-leaved bul-

EPIDERMIS.

[ 295 ]

EPIDEKMIS.

bous plant, and seizp a litllo piece of the
ragged edge with a pair of line forceps, we
may strip oft' large pieces of wliat appears
to the naked eye to be'a thin homogeneous
pellicle. When this is placed under the
microscope, it is found to be composed of a
layer of cells united tirmly together by their
sides like stones in a pavement, but loosely
connected with the subjacent tissue, which
adheres here and there to tlie detached strip
in ragged patches. The firm continuous
layer of cells is what botanists call the
ej)i(lermis of plants. Such a layer of cells
clothes the entire surface of the higher
plants, from the Flowering plants down to
those in which the organs, such as the
leaves, are reduced to mere layers of cells
like the epidermis itself, as in the Mosses.
In a very young and delicate state, such as
we find it clothing the surface of organs
still concealed in buds, or of young ovules
in the ovary, it has been called epiUema.
A ratlier more solid form, but still soft and
devoid of thickening layers, such as exists
on the surface of the growing parts of root-
lets Sec, is called epithelium. Both these
terms appear useless, and only calculated
to confuse the student still more than the
use of the words epidermis and cuticle,
■which already endanger misconception from
the very different characters of the struc-
tures called by those names in animal
organs.

When a layer of epidermis is macerated
in nitric acid, a thin pellicle, destitute of
cellular structure, becomes detached in
sheet-s from the outer surface of the plate of
epidermal cells; this is the cuticle (fig. 199)

Cuticle of a cabbage-leaf, removed by the action of nitric acid

r, hairs; F, oriHces corresponding to stomata.

Magnified 250 diameters.

of botanical anatomists, concerning which
much njisconception has prevailed. As
epidermis advances in age it becomes con-
siderably solidified, especially on evergreen
leaves, and on shoots of shrubs &c. which
remain green for a lengthened period, such

as Aucnhn and J'isoim. In most cases, how-
ever, the epidermis of structures belonging
to the stem disappears about the same time
as the leaves fall oft" and is replaced by the
suberous layer of the bark structure, which
change is evident externally by the surfiice
assuming a brown colour, the subjacent
tissue containing chlorophjdl being hidden.
The green colour of parts clothed with epi-
dermis depends upon the subjacent tissue
showing through the transparent epidermis,
the cells of which are usually colourless, and
filled with watery contents.

When sections are made perpendicularly
to the surface of any fidly developed leaf,
but above all of those of leathery texture,
the walls of the cells next the external
surface are found much thicker than the
rest, this thickening extending more or less
down over the contiguous side walls. When
such sections are treated with sulphuric acid
and iodine, the greater part of the thick-
ness, from without inward, of this outer
wall is stained yellow, while the rest of the
walls assume the blue colour ordinarily
taken by cellulose with these reagents.
Some authors suppose that the whole of
this yellow part corresponds to the cuticle
above mentioned: but such is not the case;
if such a section is boiled or macerated for
a long time in solution of caustic potash,
then washed well with water and treated
with tincture of iodine, the thick upjjer
wall also assumes the blue tint, and, more-
over, a laminated structure becomes evident
in it, sho\\dng that it is produced by the
deposition of secondary layers inside the
cell. The true layer of cuticle (which is
dissolved off" by the continued action
of potash) is really extremely thin
in almost all cases. The true nature
of this thickening of the outer walls
is well illustrated by the epidermis of
Viscum (Mistletoe), which remains
tipon the shoots for many years ; here
several layers of cells subjacent to the
original superficial stratum become
involved in the process of solidifica-
tion, and their cavities completely
filled up by the secondary deposits.
The true structure of the enormously
thick epidermal layer of old shoots,
as brought out by the action of potash, is
seen in the example of PI. 47. fig. 26. The
true cuticle is sometimes of considerable
thickness, as in the leaves of Cyeas (PI. 47
fig. 28). The thickening layers of the epi-
dermal cells are true Secondary Deposits.

EPIDERMIS.

[ 296 ]

EPIDER^nS.

The nature of the cnfide is yet ixncertaiu ;
some regard it as a kind of excretion har-
dened over the surface, otiiers as the per-
sistent original outer wall of the parent-cells
of the epidermal cells, metamorphosed che-
mically where exposed directly to the action
of the air (in a manner analogous to that in
"which the parent-cell membranes become
converted into a gelatinous investment of
the filaments of Confervfe, the cells of Pal-
mellaceaj, &c.). This seems borne out to
some extent by the change of condition of
the consolidated part of the outer walls,
coloured yellow by sulplunic acid and iodine ;
but it is unlniown wlaether there is here a
real chemical change, or merely an infiltra-
tion capable of being removed by the action
of potash (see Secondaby Deposits),

Although the cellular plants possess no
true epidermal layer, the superficial cells
form a kind of cortical struetiu'e in the
Lichens and larger Algte ; and in the lower
Algae the cells of the filaments «S:c. compo-
sing the fronds bear some resemblance to
epidermal cells in structure, insomuch that
they have laminated walls (partly produced
by the persistence of those of the parent
cell after cell-division), with the outer layer
possessing much of the physical character
of the cuticle of the higher plants. As just
mentioned, the gelatinous sheaths of the
lower Algae must be regarded as a kind of
cidicle, and as produced by gradual disor-
ganization of the outer layers of membrane
while cell-development and the formation
of new layers is going on Avithin. For
further discussion of the nature of the
thickening layers of epidermis, see Inter-

CELLULAR SuBSTANCE.

The epidermis and its appendages offer a
great variety of points of interest to the
microscopist. The epidermis of those grow-
ing parts of the higher plants which are
exposed to the air is not absolutely con-
tinuous and without orifices like the epi-
dermis of roots, but is perforated with
myriads of breathing-pores or stomata
(fig. 200, s) as they are called. These con-
sist of gaps left by the separation of the
superficial epidermal cells at their meeting
angles, the interspace between th(>m being
guarded and more or less filled up by
(usually) a pair of cells, situated just be-
neath the outer orifice, and having a slit-
like passage between them.

Hairs, scales, thorns, stinr/s, and the
various forms of (/lands of plants, are ap-
pendages of the epidermal structure, being

Fig. 200.

Epidermis from petal of the balsam, with stomata, S.

The epidermal cells here have elegantly sinuous

side walls.

Magnified 200 diameters.

produced by the peculiar development of
particular cells or groups of cells of this
superficial layer.

We have already alluded to the different
conditions of the epidermis in different parts
of plants. The delicate layer covering young
organs in buds becomes very variously deve-
loped as these attain the complete conditions.
On the leaves and shoots the epidermis be-
comes consolidated by secondary deposits,
and this in greatest proportion on leathery
or woody leaves, &c., such as those of ever-
greens, shrubs, and trees. Remarkable ex-
amples of this may be found in the leaves of
the ProteacejB, Cycadaceae, the Holly, Box,
itc. (woody), and in the ^Vloes, Cactaceae,
Oleander, Ilakea, Ficus, kc. (leathery). In
all cases the solid character of foliage de-
pends almost exclusively up(m the character
of the epidermis by which the leaves are
clothed. The epidermis of the outer scales
of the winter-buds of trees is remarkably
thick. The thickening layers are some-
times found on the walls of the stomatal
cells and adjacent cells bounding the inter-
cellular cavity, forming the pseudo-struc-
ture called a cistome (see Stomata).

The epidermis of petals and similar deli-
cate organs never acquires much solidity;
but the outer walls often become elevated
more or less above the surface, producing a
minute papillosity of the epidermis, which
gives the peculiar gli.-~teuing appearance.
When this elevation goes still further, villi

EPIDERMIS.

[ 297 ]

EPIDEEmS.

or short h;iirs are produced, rendering tlie
surface volvety (see Hairs).

The side walls of epidermal cells are
sometimes flat faces of tolerably regular
geometrical figures, such as cubes, parallel o-
pipeds, hexagonal prisms, Sec. ; but not un-
IVequently they are very sinuous, and then,
when the epidermis is seen from above, it
does not look like ordinai'v parenchyma,
with square, rectangular, or hexagonal tes-
sellae, but the component cells are fitted
together so as to pi'esent lines, which, when
regular, might be described by the heraldic
terms scallopped,wavy, indented,&c. (PI. 47.
fig. lo), and when less regular resemble
roughly the lines of j oint in the old-fashioned
puzzle-maps of children (fig. 200). Such
forms of the epidermis are frequently found
on petals, on the leaves of Ferns, on those
of Hellebore, &c., and constitute very pleas-
ing microscopic objects; especially as, in
addition to the lines, the stomata at the
angles add to the elegance of the pattern.

The cuticle on many petals, as those of
the Daffodil, and on leaves, as those of the
genus Hellehorus, Diantlius, Sec, when the
epidermis is viewed from above, exhibits
elevated strise running in various ways over
the surface, sometimes converging in the
centre of each cell, in other cases running
in tortuous lines over the siu'face, con-
tinuous beyond the boundaries of the indi-
vidual cells. A similar condition of the
cuticle occurs upon the haiks of many
plants, especially of Cruciferye, Ranuncu-
lacese, Boraginege, Sec. This condition is
evidently analogous to the equally myste-
rious states of the outer membrane of PoL-
LEX-GRAiNS and Sporrs, where points,
ridges, reticulations, &c. of the same kind
constantly occur.

The stomata are found on both surfaces of
manv leaves of delicate structure, but most
abundantly on the lower surface ; in other
plants they occur exclusively on the lower
face ; in floating leaves they exist only on
the upper face ; while on submerged leaves
none at all occur, and the epidermis here
has no very distinct difference from that of
young roots. The characters of Stomata
are spoken of more at length under that
head, as also those of H.\ies, Scales,
Stings, Thoexs, Gi.axds.

The cutic«lar layers of the epidermis
often contain deposits of wax upon or with-
in the tissues. De Bary distinguishes four
kinds : — 1, heaps of granules in several
layers, or of delicate needles, as in Euca-

lyptus, Aracifc, grasses, Sec. ; 2, a simple
layer of grains, in Allium cepn, Brns^ica
oleracea, Sec. ; -3, a layer of rods perpendi-
cular to the surface, as in Musarete, Saccha-
rum, Sec. ; and 4, a membranous wax-layer
or crust, as in Sempcrvioum, Thuja, and
Taxus. Some of the wax-grains are not
recognizable until the tissues are heated to
212°, when they form drops.

The epidermis of the Equisetacese and
the Grasses is remarkable for the deposition
of silica, apparently in the walls of the cells
of the epidermis, to such an extent and so
equably, that the whole of the organic
matter may be removed by heat or acids,
and a perfect skeleton of the structure be
obtained, composed exclusively of silex,
exhibiting the boundary lines of the epi-
dermal cells and the stomata (the dentate
side walls, with the stomata arranged in
linear series, are described in most micro-
scopic books in a very curious manner, from
an old paper by Sir D. Brewster). Prepa-
rations of this structure are obtained by
treating little pieces of the wall of the fistu-
lar stem with strong nitric acid, to remove
alkalies, and then burning them until quite
white on a slip of platinum or very thin
glass. These should be mounted in Canada
balsam.

In the Equiseta, the siliceous films thus
obtained are covered with minute spines,
presenting somewhat the dotted appearance
of the valves of the Diatomacete.

The seeds of many plants are clothed
with an epidermis of remarkable character,
the cells containing spiral fibres ; this oc-
curs in the Acanthace.^, in Collomia,
Salvia, &c., and is further treated under
those heads and under Hairs and Spiral
Structures.

BiBL. Mohl, Veqetahle Cell, 1852, Li^irusa,
xvi. 401, Verm. Schrift. 200, Ann. Sc. Nat.
2 ser. xix. 201, ibid. 3 ser. iii. 158, Bof. Zeit.
V. 497 (1847); ibid. vii. 593, 1849; Schlei-
den, Wiss. Bot. 3 ed. 335 (Principles, 70) ;
Brongniart, A)in. Sc. Nat. xviii. 427, 2 ser.
i. 65; Link, Eletn. Fhil. But. i. 83 ; Wigand,
Intercelhdar-Substanz u. Cuticula, 1850 ;
Karsten, Bot. Zeit. vi. 729, 1848; Cohn,
Linn(su, xxiii. .337, 1850 ; 'Raxi\g, EnttvicH.
der Pfl. 1843, Ann. Sc. Nat. 3 ser. i. 352 ;
linger, Bot. Zeit. v. 289, 1847 ; Garreau,
Ann. Sc. Nat. 3 s^r. xiii. 304 ; Mulder and
Harting, ilf «/(/e?-'s P/»/s. Chem.\ Goldmann,
Bot. Zeit. vi. 857, 1848 ; Schacht, Pflan-
zenzelle, 89, 1852 ; Wiesner, Techn. Mikr.
1867 ; Leitgeb, Denkschr. Wien. Ak. 1865,

EPIPYXIS.

[ 298 ]

EPITHELIUM.

xxiv. 25.*) ; Thomas, Jahr. wiss. Bat. iv. 33 ;
Pfitzer, ibid. vii. 561, and viii. 17; I)e liarv,
Bot.Zeit. 1871; Sachs, i^oi?. 1874; Ileafrey-
Masters, Bot. 1878.

EPIP YXTS, Ehr.— A genus of Flagellate
Infusoria, of the family Diuobiyina.

Char. Fixed by a pedicle ; eye-spot
absent ; no cilia nor appendages.

E. utriculus (PI. 30. tig. 50). Carapace
urceolate ; body filled with yellowish gra-
nules ; on Conferva; length 1-650".

Probably the young state of Diiiohrj/on
sertidnria, like which it contains a disk-
shaped nucleus.

EiBL. Ehrenb.7///(«.123; Kent,Jn/"M.s.400.

EPISTY'LIS, Ehr.— A geims of Infu-
soria, of the family "Vorticellina.

Char. Pedicle rigid, not contractile,
simple or branched ; all the bodies of the
animals of the same form.

Claparede and Lachmann refer the species
of Opercularia to this genus.

Stein has pointed out the occurrence of
the encysting-process in the species of this
genus ; and indicates the presence of a lid-
like discoidal process, protrusible from the
orifice, as in Vorticella, furnished with
vibratile cilia ; but this does not occur in
all the species admitted by Ehrenberg. The
species are numerous, and mostly attached
to aquatic animals or algte. Clap, it Lachm,
admit 10 species.

E. anastatica (PI. 30. fig. 51 a, c). Body
small, conical, not plicate, anterior margin
large and projecting; pedicle dichotomous,
smooth, or covered with minute or foreign
bodies ; entire lenii-th 1-14-4 to 1-14" ; of
single body, 1-288''.

E. gra)idis. Body large, broadly campa-
nulate; pedicle decumbent, slender, smooth,
laxlv branched, not jointed, forming large
tufts ; length of body 1-140 to 1-120".

E. vegetans (Anthophysa Mi'illeri, Buj.).

BiBL. Ehrenb. Iiifns. 27!); Stein, /»/. ;
Claparede and Lnchmnnn, Inf. 107; Tatem,
Mic. Tr. 1868, 31; Kent, liif. 700.

EPIT'EA, Fr. See Ukkdinei, Pheag-
MiDiuM, and Mf.lampsoha.

EPITTIE'LIUM. — The membranous
layer lining the various internal cavities,
and covering the internal free surfaces of
animal bodies, as the mucous canals and
cavities, and their involutions forming the
glands and ducts, the serous cavities, the
vessels, &c.

It consists of one or more layers of nu-
cleated cells, the form and arrangement of
which are very variable. They are either

round, polygonal, spindle-shaped, cylindri-
cal, or conical ; and are united by a small
quantity of intercellular substance. They
contain a clear or granular nucleus, with
one or more nucleoli. In some instances
they contain granides of black pigment or
melanime.

Three kinds of epithelium are usually
distinguished ; but intermediate forms are
also met with.

Pavement- or tessellated epithelium,.
This consists of roundish, oval, or polvgonal
flattened cells, about 1-2000 to 1-500" in
diameter, and containing nuclei with nu-
cleoli. It occurs upon the surface of the
serous and synovial membranes ; the mem-
brane of the aqueous humour, the choroid,
the capsule of the lens, the retina, and the
conjunctiva of the ball of the eye ; the ca-
vity of the tympanum ; the lower half of
tlie pharynx, the oesophagus, the endocar-
dium ; some veins ; many glands and ducts,
as the racemose, the sudoriparous and ceru-
minous glands ; the hepatic ducts : the
vagina and female urethra ; the bladder,
uterus, pelvis, and tubules of the kidneys ;
and the air-cells of the lungs. In the arte-
ries and many veins the cells are spindle-
shaped.

Cylindrical epithelium. In this form the
cells are either cyhndrical, conical, or pyra-
midal, about 1-1000" in length, and so
situated that the axis of the epithelial scal(>s
or cells is at rigbt angles to the surface upon
which they are placed. Sometimes the sub-
jacent cells are of a rounded form.

Cylinder-epithelium is met with in the
mucous membranes, inLieberkiihn's follicles,
and the ducts of the gastric as well as those
of all other glands o^jening into the intes-
tine ; in the lachrymal and the mammary
glands ; the male urethra ; the vas deferens ;
the vesicidas seminales, the prostatic ducts,
with Cowper's and the uterine glands.

Ciliated epithelium. In this the form
and aiTaugement of the cells is much the
same as in the List ; but their free ends
are furnished with numerous vibratile cilia
(PI. 40. fig. 13).

Ciliated epithehum occurs in the larynx,
trachea, and bronclu ; the nares and pha-
rynx above the level of the base of the nasal
bones, and the cavities opening into them ;
the inner surfiice of themenibrana tympani,
the Eustachian tube ; the- uterus, the Fallo-
pian tubes ; the lachrymal sac and nasal
duct; the ■ palpebral conjunctiva; and the
ependyma.

EPITHELIUM.

[ 299 ]

EQUISETACEyE.

In most opithelia, the cells and tlioir
nuclei are readily distinguished ; but in
others, especially those of the vessels and
serous membranes, staining with magenta,
kc, is required to render the nuclei dis-
tinct, and silvering to bring out the cell-
boundaries, (See Staining.)

In many cases, intervals are left between
the epithelial ci'lls, usually at the points
where several cells meet ; these are called
stomata. They are often connected with
the lymphatic system. See Stomata.

The epithelium covering the outer svu-
face of the body forms the epidermis or
cuticle.

Further particulars of the special forms
of the cells are given under the heads of
the organs or tissues in connexion with
which the epithelia are found.

BiBL. KoUiker, Mikr. An. and Handb.
d. Geivebel. ; Valentin, Tfcu/iier's Handb. d.
Pliys., art. Flimmerbeiveyunf/ and Epitltel. ;
Henle, Allgemein. An. ; Todd and ] bow-
man, Phys. ; Frey, Histologie, 1876, 153 and
the full literature.

EPITHELIUM OP Plants. See Epi-
dermis of Plants.

EPITHE'MIA, Brebisson.— A genus of
Diatomacea3.

Char. Frustules suigle, attached by a part
of the surface to other bodies ; valves with
transverse or slightly radiant strias, some of
them not resolvable into dots.

Frustules prismatic, quadrangular, mostly
curved, sometimes slightly undulating in
the side view ; one face of front view (that
by which they are attached) flat or con-
cave, the other convex and broader than the
former, so that the transverse section forms
a trapezoid. Between, or corresponding
with the transverse striae, which are not
resolvable into dots, are often transverse
rows of dots or depressions.

The species are numerous. Fi'eshwater
and marine. Rabenhorst describes 21 Eu-
ropean. Conjugation has been observed in
three of them.

E. turyida (PL IG. fig. 32 : a, side view ;
h, front view). Front view oblong, slightly
dilated towards the middle ; side view some-
what convex, g-radually attenuated towards
the very obtuse ends. Freshwater ; length
1-240".' In conjugation, PL 10. fig. 6 a, b,
c, d, e.

E. gibba (PI. 51. fig. 6). Straight ; in-
flated in the middle on each side in front
view ; A^alves gibbous in the middle on one
side J freshwater and fossil; length 1-140".

BiBL. Kiitzing, BnciUar. 33, and Sp.
Aly. 1 ; Smith, Brit. Diatom, 1. 13 ; Ra-
benhorst, Sp. Al(). i. 02.

EPOCIPNIUM, Lk.— A genus of Toru-
lacei (Hyphomycetous Fungi), forming a
stratum over larger fungi or dead twigs,
consisting of a mycelium of irregularly
branched and anastomosing filaments, which
bear, on short lateral branchlets, oblong or
globular septate spores, which soon faD off
and lie among the mycelium-threads,

E. fungorum is very common, forming' a
dark-green stratum over Thdephorce; E.ma-
crosporoidium was found by 13erkeley on a
dead twig, apparently of red currant.

SphcBria Epochnii, B. & Br., has been
found on Epochnium fungorum:, and it is
very probable that it is the perfect state of
a conidiiferous mycelium.

BiBL. Berk, in Brit. Flora, vol. ii. pt. ii.
3o2 ; An7i. N. H. i. 263, pi. 8. fig. U.

EQUISETA'CE^E and EQUISE'TUM.
— This is a very distinctly characterized
family of Flowerless Plants, consisting of a
single genus, the Equiseta, or Horse-tails,
which are immediately recognized, when
one species is known, by their peculiar aspect
andhabit of growth. The stems and branches
are alike tubular, and present in almost all
cases a rather coarsely (per-
pendicularly) streaked sur-
face. The stems appearing
above ground are shoots
from a creeping under-
ground stem (fig. 201),
which differs from the
erect stems in being of
a deep brown colour and
solid, in giving off root-
fibrils, and sometimes in
being covered with hairs.
The erect stems are either
barren or fertile ; in the
barren stetns the joints be-
come gradually thinner
upwards from a certain
point, at last tapering off •
to an obtuse apex; the fer-
tile stems bear a kind of
club-shaped head, resem-
bling in some degree the Equisetum arvense,
male cones of Coniferous One half of
trees, or more particularly "'i'- ^'^e,

those of some Cycads (fig. 201). These
club-shaped bodies are the fruits or heads
of sporauges.

The anatomical structure of the rhizome
and shafts present some interesting points.

201.

EQUISETACE-E.

[ 300 ]

EQUISETACE.E.

In the solid rhizome the centre is occupied
by cellular tissue of tolerably strong texture ;
outside this, as seen in a cross section,
stands a circle of air-canals, each surrounded
by a ring of vascular bundles ; next comes
a complete cii'cle of vascular bundles com-
posed almost wholly of annular ducts ; be-
tween this vascular ring and the outside
lies parenchyma like that in the centre,
traversed by another concentric circle of
air-canals ; and immediately beneath the
epidermal cells there exists a layer of com-
pact blackish-brown parenchymatous cells.
When the rhizome is coated with hairs,
these are formed by development of the
epidermal cells into slender tubular pro-
cesses. Tracing the solid rhizome up to-
wards the points where the erect stems
arise, the central cellular substance is gra-
dually lost, and the outer portions are mo-
dified in their arrangement. The distribu-
tion of the air-canals and the vascular bun-
dles varies; in some cases, the peculiarities
are even regidar enough to afford specific
characters. The surface is clothed by an
epidermis composed of elongated cells often
elevated into papillfe, and especially re-
markable for the quantity of silica deposited
in their walls. This epidermis is studded
with variously formed stomata usually
an-auged in double lines ; and the foi-ms of
the epidermal cells and stomata are per-
fectly preserved in the siliceous ash which
remains after burning off the organic sub-
stance from a portion of this EPiDEEiiis,
offering a curious microscopic object. Be-
tween the epidermis and the central cavity,
in a cross section lie — first, a layer of thick-
walled elongated cells, -nathin which, in the
angular-stemmed species, comes a circle of
masses, usually crescentic, of cellular tissue
containing chlorophyll. Next come usually
two concentric rings of air-canals, those of
the inner circle being individually sur-
rounded by annular ducts ; and, moreover,
in some species a circle of 6-10 vascular
bundles separates the inner from the outer
circle of air-canals ; the strnctm-e of the
bundles is variable, exhibiting annular, spi-
ral, and reticulated ducts. The inner circle
of air-canals lies in the parenchyma which
bounds the central cavity. At each joint
this cavitv is cut oft" by a diaphragm com-
posed of three layers,' in the intermediate
of which, of brownish cellular tissue, Hes an
anastomosing ring, where all the vascular
bundles coalesce and give off branches to
the sheath (and branches when present).

The club-shaped fruit-spikes consist of a
central axis forming the last joint of the
stem, on which are attached numerous
mushroom-shaped gi-oups of sporam/es, the
stalks of each adhering to the central axis,
so that we only see the upper side of the
cap externally (figs. 202, 203). This has
an angular border ; and the adjacent spo-
ranges being veiy close, the outer ends of
these bodies cause a tessellated appearance
of the whole in the earher stages of de-
velopment. As the sporanges ripen, they
separate more from each other ; and when
one is removed (fig. 204), it is seen to
possess a number of httle pouch-like cases
imder the overhanging outer portion and
roimd the stalk ; these pouches burst by a
perpendicular slit inwards, and discharge
the spores.

Fig. 202.

Fig. 203.

Fig. 204.

Fig. 205.

Eqnisetiun arvenae.

Fi-^. 202. Fruit-spilco. Magnified 3 diams.

Fig. 203. A spike halved vertically. Magn. 3 diams.

Fig. 201. A stalked group of sporanges removed from

preceding. Magn. 25 diams.
Fig. 205. A sjiore with elaters uncoiling. Magn. 200

diams.

The spores of the Equiseta are very re-
markable, and unhke any other Icno^ni ve-
getable structure. They are roundish cells,
with apintrenfly only one coat; for the outer
coat splits up" into four thread-like pro-
cesses {elaters), thickest and rather clubbed

EQUISETACE^.

[ 301 ]

ERIODERMA.

at their free ends. "While the spore renifiiiis
in the sporange, those tibres are rolled round
the spore ; but when the spores are dis-
charged, the coiled fibres uncm-1 (fig. 20-")),
and assist in scattering the spores, their
elasticity causing them to spring out.

The Equisc'ta possess only this one kind
of spore ; and the germination is analogous
to that of the Ferns, in which likewise only
one kind of spore exists. The membrane
of the spore pushes out a pouch-like pro-
cess, which after a time becomes cut oft"
by a septum ; the end-cell grows on and
niultiplies in both directions, until a lobu-
lated prothallium is produced ; on this arise
arehc(jonia and antheridia, in distinct indi-
viduals, the archegonial prothallia being
larger than the antheridial, and resembling
in all essential respects those produced on
the corresponding structure in the Ferxs.
The antheridia are formed on the ends or
the margins of the male prothallia. The
sjiermatozoids are larger than those of other
Cryptogamia ; they have 2 or 3 coils, the
posterior thickened portion being furnished
with an appendage, supposed to consist of
an imdidating membrane.

After the fertilization of an archegonium,
the germ-cell contained in it becomes deve-
loped as an embryo, and a new Equisetum-
stem of the ordinary structui'e springs up
(tig. 206), forming a creeping rhizome with

Fig. 206.

Equisetum arvense.

Young stem arising from a prothallium.

Magnified 15 diameters.

upright fistular shafts, resembling the parent
plant from which the spores were derived.
The family Equisetacese is represented
in existing vegetation by a single genus,

containing only herbaceous plants. The
Equisetacete of former ages were far more
important as regards size.

jjiBL. Francis's British Ferns, 5th ed.
1855 ; Thuret, Ann. Sc. Nat. 3 ser. xi. 5 ;
Milde, But. Zeit. viii. 448, and x. 5:57,
Linncca, xxiii. 545 ; Hofmeister, Vercjleich.
Unters. 1851, Verh. k. Siichs. Akad. d. Wiss.
iv. 123 ; Bischoff, Krypt. Geivlichse, Heft 1,
27, pis. 3, 4, 5, Botan. Zeit. xi. 97 ; Prings-
heim, Bot. Zeit. xi. 241 ; Sanio, Bot. Zeit.
xiv. 177, XV. 657: Milde, A^om Acta, 1867,
XXXV. ; NageliandLeitgeb,ArtV/.5ej^.iv.l867;
Janczewsky, Bot. Zeit. 1872, 420 ; Tieghem,
Ann. Sc. Nat. 5 ser. xiii. ; Sachs, Bot. .389.

EREBONE'MA, Rcim.— A supposed ge-
nus of Kiitzing's family Leptomitese. Some
imperfect filamentous organism, probably
belonging to a Fungus.

BiBL. llomev, DeutscJd. A!(/. 70 ; Kiitzing,
S^}. Ah/. 157.

EREM^E'US, Koch.— A genus of Ori-
batidas (Acarina).

Char. Cephalothorax without lamellae ;
tarsi with heterodactyl claws. AUied to
Hoplophora. (Murrav, Be. Ent. 222, fig.)

EEE'MOSPH^ERA. See Chloiio-

ERE'TES, Werneck.— A genus of Infu-
soria, of the family Crvptomonadina.

Char. Those of Phacelomonas with a
carapace.

One species : the spores of an Alga ?

BiBL. Werneck, Ber. Berl. Ak. 1844,
377.

ERGOT and ERGOT^'TIA. See Cla-

VICEPS.

ERIN'EUM, Pers.— A supposed genus
of Fimgi, really consisting of abnormal de-
velopments of "the cells of the epidermis of
the trees upon which they are supposed to
be parasitic; or galls, produced by the action
of Phytoptidae. They occur chiefly upon
the Amentacefe, Aceracese, and Rosaceae
(Apple-trees, Plum-trees, &c.).

See Taphrina.

BiBL. Fries, Sijst. Mycol. iii. 521 ; Berke-
ley, Bindleifs Vey. Kiniidom, art. Fungales ;
Murrav, Ec. Entom. 331.

ERiODER'^MA, Fee.— A genus of tro-
pical Lichens, tribe Lecanorei, externally
resembling the Peltigerae ; consisting of a
green membranaceous thallus, spreading
from the centre, hairy above, and with
woolly anastomosing nerves beneath. Apo-
thecia marginal, with hispid hairs on the
margin underneath.

Bibl. Fee, Cryjit. 145, pi. 34. fig. 2.

ERIOSOMA.

[ 302 ]

ERYSIPHE.

ERIOSO'MA. See Aphid^.

ERIOSTORA, Berk. & Br.— A genus
of Sphajronemei (Stylosporous Fungi j, do-
scribed (E. leucosfoma) a,3 foiTuing minute
brown spots upon dead leaves of the bulrush.
The conceptacles are globose, and collected
in numbers on the stroma, bursting by a
single common (white-bordered) pore to
discharge the spores (stylospores), which
are filiform and very slender, and arise in
fours from a sporophore. (See Coniomy-

CETES.)

BiBL. Berk, and Br. Ann. N. H. 1850,
V. 455, pi. 11. fi^. 1.

ERUPTIONS, CTTTANEOUS.— The scales,
crusts, scabs, contents of vesicles, pustules,
&c. formed in various diseases of the skin,
usually consist of epidermic cells alone,
more or less fiatteued or othei'wise altered,
or of these with the ordinary products of
inflammation. Granules of soot are fre-
quently found, in London at least, mixed
with the above elements ; and these were
once regarded as the microzymes of small-
pox. Fmigi exist in the crusts of some
skin-diseases, as FAvrs, &c. The itch-
insect, Sarcoptes, must not be forgotten,
nor Demopex. See Parasites.

ERVIL'IA, Duj. {J^f/yHa,C\. k Laehm.).
— A genus of Infusoria, of the family
Ervilina.

Char. See the family. Marine.

E. ler/nvien = Enplotes monoxtyhis, E.
(PI. 30." fig. 52 ; h, side view). Body with
two ventral contractile vesicles ; length
1-650 to 1-420".

3 other species.

BiBL. Duj. Infus. 455 ; Clap. & Lachm.
Inf. 288.

"ERVILI'NA, Duj. (Dysterina, CI. &
Lachm.). — A family of Infusoria.

Chen'. Body oval, more or less depressed,
entirely or partly ciliated, with a tail-like
foot, usually also with a persistent mem-
branous carapace.

Genera :

Carapace present.

Composed of two distinct valves Idiina.

Composed of two united valves.

Valves united behind and below only ... Dyfteria.

Valves united all dovm the back F.rriUa.

Carapace absent Hiuleyia.

Dujardin questions whether Urocentrum,
E., does not belong to this family.

BiBL. Duj. hifus. p. 454; Clap.& Lachm.
Infus. p. 278.

"ERY'SIPIIE, Hedw. fil.— A genus of
P^n-enoniycetes (AscomycetoTis Fungi),
consisting of little mildews overgTowing the

leaves of living plants, mostly Dicotyledons.
The mycelium is formed of slender ramified
filaments, which spread and form an en-
tangled web over the epidermis of the in-
fected plant, sending into the substance
sucker-like processes or hausteria, by which
nourishment is obtained from the juices of
the leaf. From the creeping mycelium arise
numerous upright short-jointed filaments,
the last one or more of the cells or joints
of which sweUs so as to render the erect
filament clavate or monihform. These ex-
panded cells become detached with the
greatest readiness, and, w^hen they fall upon
the supporting leaf, germinate and produce
new mycelium threads. In this state the
Erysiphce cannot be distinguished from the
genus Oidiiim; and as this state is succeeded
in most cases by the true conceptacle of
the genus En/siphe, the Oidia (such as
O. Tuckeri, the Vine-fungus), which grow
under the same circumstances, but do not
produce conceptacles, are regarded by most
authors as iwpevfectEn/siphcs. (See Oidium,
PL 26. figs. 12-14.) \Vhen the mycelium
of an Erysiphe is developed late in the year,
it seldom produces any thing but the ovate
cells {conidia); but if developed early in the
summer, the mycelium grows at certain
points into denser white ^atahes {receptacles,
Lev.), fi'om which arise the conceptacles,
which are fertilized by poUinodia, as in
Eiirotinm. These are small globular sacs,
composed of a double layer of cells ; from
the base of the outside of the sac arise a
number of radiating filaments, simple or
branched (appetidicles, Lev.), while in its
interior are developed one or many sacs,
(asci, sporanges, Lev.), in each of which
are produced mostly eight sporidia. In
addition to the above, a third form of fruit
occurs, in which the conidium becomes
transformed into a sac (pycniduuu) filled
with minute spores. Tulasne has figured
a second form, apparently of conidia, in
Phyllactinia gidfata.

Leveilld, in an elaborate essay on this
genus, has subdivided it into six genera,
which may perhaps be better taken as sub-
genera, and may be distinguished in the
following manner : —

Conceptacles with one asciis.
Appendicles dichotomously branched. . . Fodosphtpria.
„ floocose Sphoerotheca.

Conceptacles with v\any asci.

„ aciculate FhyVactinia.

„ uncinate Vncinula.

„ dichotomously branched... Microsphairia,

„ floccose Erysiphe.

\

ERYSirHE.

[ 303 ]

EUACTIS.

Podo^phrrrid. Tlio TTawthorn-bliii'lit and
the rium-blijrlit bi'luiii^- to this division,

SpJuerotheca. The Hose-mildew, E. pan-
nnm, auct., belong-s to this proup, and is
di.stin<ruislied from E. maculan'x, ^\'alh•.
(S. Casfaipici, .T. lit? v.), the Ilop-mildew, by
the appeudicles of the former beinp; white,
whik^ those of the latter are cohiured. The
mycelium of the rose-mildew seems to be
the same tiling as Oidium leucocunium, Desm.
The similar structure of the Ilop-mildew
has been described and figured (from Dr.
Plondey's drawings) in the Trans, of the
Horticultural Society. He was the first to
discover the conversion of one of the oidioid
cells into pycnidia.

Phi/Uactima. E. fpiffatn, Schlecht., com-
mon on the hazel and other trees and large
shrubs, is dislinguislied from the other
forms of Phi/Udctinia by having a bulbous
base to its appeudicles, which contain 2 to
4 sporidia.

T'ncinula. E. odiinca, Schlecht., is re-
ferred here ; its distinctive character is the
existence of the hooked appendicles. Found
on willows. E. bicornis, Lk., occurring
upon maples i^'C, has eight spores.

31icrosphcpna. E. lienicillata, occm'ring
on Vibnnnnn Opnlus, &c. Several species
occur in this country, of which one of the
best-known is M. penicillata. The charac-
ters of the appendicles, which are dichoto-
mously branched at the tip, are the same as
those of Podosp/tceria ; but there are many
asci, instead of one only.

Erysiphe. E. I'm, Grey., is E. Martii
of LeveiUe, distinguished by its globose,
many-spored asci and the simple or irre-
gularly branched appendicles. E. tortilis,
Lk., has coloured appendicles ten or more
times the length of the conceptacle. It
grows on Cormts sancpdnea, the Dogwood
tree. E. communis, Lev., is not x-eiy well
ch.aracterized ; it has coloured appendicles,
which are only twice or thrice as long as
the conceptacle ; the asci vary from four to
eight, as do also the spores contained in
each. This species grows on a great variety
of herbaceous plants, Eanunculacese, Com-
positae, Leguminosaj, Cruciferse, Polygo-
nacere, &c.

Perhaps a doubt might be admitted whe-
ther the above subdivisions really represent
more than six species of this genus.

BiBL. Lt5veille, Ann. Sc. ^at. 3 ser. xv.
ion, pis. G-1 1 ; Berk., Hook. Br. El. ii. pt. 2.
325; Tr. Ilort. Soc. London, ix. Gl ; Greville,
Sc. Crypt. Fl. pis. 134, 164. figs. 2, 29G :

Tulasne, Compt. Pendus, 18-'53; Ann. Sc. Nat.
4 ser. vi. 299, and C'arpoloipa, i. 18G0; Cooke,
Handbook, 645 ; Taylor,' M. M. Jn. 1875,
xiii. 121 ; De Bary and Woronin, Peit. z.
Morph. 1870; Sachs, Pot. 312.

See also Oidium.

EliYTHR.E'US, Duges.— See Anystis.

ESCHAR'lDyE.— A family of Cheilosto-
matous Polyzoa ; containing the genera
Lepralia, Unibonula, Porella, Escharoidcs,
Smittia, Phylactella, MucroneUa, Palmicel-
laria, and Retepora.

ESCHAROl'DES, Smitt.— A genus of
Cheilostomatous Polyzoa, fam. Escharidae.

2 species ; deep water. (Hincks, Polyzoa,
336.)

ESPAR'TO.— The bast-fibres of a ^rass,
Lyyeimi spartum {Stipa tenacissima, Linn. ;
Makrochloa, Kunth), a coarse fibrous ma-
terial, extensively used in the manufacture
of paper. The fibres are shorter than those
of most allied substances : and the epider-
mic wavy margined cells are so short as to
render the distinction of this material toler-
ably easy.

It occm*s extensively in the south of Eu-
rope, in North America, and in the centre
and south of Spain.

BiBL. Henfrey-Masters,5o^.400; Wiesner,
Techn. Mikr. 225 (fig.).

ESTHE'RIA, Rlippell and Straus-Diirck-
heim (Cyzicus, Audouin ; Isatira, Joly).

A bivalved phyllopodous Entomostracon,
having 24 pairs of foliaceous limbs, and
ovate valves, horny, delicate, concentrically
ridged, bearing from 7 to 80 lines of growth,
with intermediate reticidation or other
sculpturing.

2G species are known, from fresh and
brackish waters of warm climates ; and
more than 20 fossil, Devonian to Tertiary.

BiBL. Baird, Zool. Proc. 1849, 87; 1852,
30 ; 1859, 232 ; 1860, 188 and 392 ; Rupert
Jones, Fuss. Estherice {Pal. Soc), 1862 ; E.
Grube, ^rc7?./. Naturgesch. 1853, xix., and
1865, xxxi.

EUACTIS, Kiitz.— A genus of Oscillato-
riaceaj (Confervoid A]ga3), of the tribe Rivxi-
lariese, consisting of little, hard, solid, elastic,
mostly hemispherical bodies, from 1-2 to 2'"
in diameter, growing upon stones in the sea
or rivers, &c. ; concentrically zoned, com-
posed of radiating, flagelliform, repeatedly
sheathed filaments, the sheaths of which are
open and slit above (PI. 8. fig. 16), but con-
nected together side by side, so as to form
a tough gelatinous mass, not becoming in-
crusted "with carbonate of lime. To this

EUASTEUM.

[ 304

genus Kiitzing refers Hivulann jylicata, atra,
and perhaps applunata of Harvey. These
plants are interesting- on account of the
fibrous decomposition of the gelatinous
sheaths.

BiBL. Harvev, Brit. Mar. Alg. 222, pi.
26 A (Rimtlarici) ; Kiitzing, Sp. Alg. 339 ;
Tab. Ihi/c. cent. ii. pis. 74-82.

EUAS'TRUM, Ehr.— A genus of Des-
midiacese.

Char, Cells single, compressed, deeply-
divided into two segments, which are gene-
rally pyramidal and fm-nished with circular
protuberances, lohed or sinuated at the mar-
gins, and emarginate at the ends.

Ralfs desciibes twenty-one British spe-
cies, of which the following are the most
common.

* Segments deeply lohed; end lobe distinct,
cuneate, partly included in a notch be-
tiveen the lateral lobes.

E. verrucosum (PI. 14. fig. 14). Rough ;
segments three-lohed, lobes broadly cuneate,
with a shallow notch ; length 1-2G7".

E. ohlongum (PI. 14. fig. 15). Smooth,
oblong ; segments five-lobed ; lobes cmieate ;
emarginate; length 1-156".

E. crassum. Smooth ; segments three-
lubed, subquadrilateral ; end lobe cuneate ;
length 1-190 to 1-130".

** Segments simtated ; end lobe exserted and
united with the basal po7'tion by a distinct
nech.
E. didelta (PI. 14. fig. 16; 17, empty
cell). Segments with inflated base, inter-
mediate tubercles, and notched and scarcely
dilated ends; side view, four shallow lateral
lobes, and one at each end ; length 1-185".

*** End lobe indistinct ; frequently a process
or acute angle at the corners of the ter-
minal portion.

E. elegans. Oblong ; ends emarginate,
pouting, and roimded ; length 1-890 to
1-420".

Conjugation has been observed in several
species ; the sporangia are spherical, _ with
conical tubercles, or acute or obtuse spines.

BiBL. Ralfs, Brit. Desmid. 76; Raben-
horst, Fl. Alg. iii. 179.

EUCAM'PIA, Ehr. — A marine organism,
allied to the l)(\smidiace?e, among which it
is placed by Kiitzing, whilst Smith refers it
to the Diatomaceaj.

It forms articulated, arcuate or spiral,
fasciteform, microscopic fronds, composed

] EUCHLANIS.

of hyaline wedge-shaped frustules, with
yellowi>h granular contents. Tlie joints
shrink in drying, and are destroyed by heat.
The marldngs consist of dots.

E. zodiacus (PL 50. fig. 10). Frustules
with a median excavation on each side ;
valves elliptical; length 1-710".

E. britannica. Frustules not excavated ;
length 1-380".

E. striata. Valves circiUar ; endochrome
green.

BiBL. Ehrenb. Ab7i. Berl. Ak. 1839, 125;
Kiitzing, Sp. Alg. li>l, Bacillar. pi. 21. fig. 21 ;
Smith, Br. Dint. ii. 25 ; Stolterforth, Jn. M.
Soc. 1879, ii. 835.

EUCERTYDTUM, Ehr.— A genus of
Polycystina.

E. ampulla (PI, 39. fig. 25, front view ;
fig. 26, imder view).

See POLYCYSTIXA.

EUCIILAJS^IDO'TA, Ehr.— A family of
Rotatoria.

Char. Rotatory organ multiple, or divided
into more than two lobes ; a carapace pre-
sent.

The carapace forms either a testa or a
scutellum ; various appendages are present,
representing either straight bristles, cm'v-jd
bristles or hooks, minute horns — so-called
respiratory tubes or antennae, — and in one
genus a frontal hood.

The eleven genera are thus distinguis^^ed :

Eyes absent; foot forked ^ Sf/ff

Eyes present.
Eye single (cervical).
Foot styliform.

Carapace depressed Jlononfyla.

„ prismatic Alastigocerca.

Foot forked.

Carapace open beneath Euchlanis.

„ closed beneath.

Carapace with horns Salpina.

,. without horns Diiwcharis.

Eyes two (frontal).

Foot styliform Moyioctrca,

„ forked.

Carapace compressed or prismatic. Cohtrus.
„ depressed or cylindrical.

Head without a hood Metopidia.

„ with a hood Siejihanops.

Eyes four; foot forked Squaiiiella.

BiBL. Ehrenb. Itifus. p. 455.

EU'CHLANIS, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eye single, cervical ; foot forked ;
carapace cleft or open on the ventral surl'ace.
Aquatic.

Ehronberg describes six species, to which
Gosse adds three.

E. triquetra (PL 43. fig. 30; fig. 31, teeth).
Carapace very large, with a dortal crest;
foot without setae ; length 1-48".

EUCRATEA.

[ 305 ]

EUGLENA.

BiBL. Elu-enb. Infus, 461 ; Gosse, Ann.
N. 11. 1851, viii. 200.

EUCRAT'EA, Lanix. {Scruparia).—K
genus of Cheilostomatous lufundibulate
Polyzoa, of the family Eucratiidaj.

i'. chelata ( V\. 86. tiir. 24), the only species.
Parasitic upon Fuci, crabs, and stones.
(Hiucks, Fo/i/zoa, 11.)

EUCRA'tllD.E (Sciupariada?). — A
family of Ckeilostomatous Infuudibidate
Polyzoa.

Distinguished by the unjointed polyzoary
and the uniserial cells. Polyzoary usually
loosely adnate. Five genera :

Eucratea (Scruparia). Erect, branched,
branches arising from the horn-shaped cells
above or below the oblique oritice.

Ilijypothoa. Creephig, adherent, irregu-
larly branched or netted, branches arising
fi-om the sides of the cells.

Salpimjia (PI. 36. fig. 25). Erect,
branched ; cells elongated, with trumpet-
shaped processes at the base, oritice oblique,
lateral.

Anguinaria {JEted). Cells tubular, scat-
tered, arising from a creeping, adherent
thread.

Beania. Cells erect, scattered, with a
double spinous keel on one side, and arising
from a creeping, adherent, branched thread.

BiBL. Johnston, Br. Zooph. 288 ; Busk,
Mar. Polyz. 28 ; Gosse, Mar. Zool. ii.
12 ; Hincks, Polyzoa, 11.

EUCYTHE'RE, Brady {Cijtheropsis,
Sars). — A genus of marine Entomostraca,
fam. Cytheridse.

2 species.

BiBL. Brady, Linn. Trans. 1868, p. 429.

EUDEN'DRnD.E (Tubulariidas, pt.,
Johust.). — A family of Hydroid Polypi.
Characterized by the branched stem, and
the terminal naked polypes, with a single
whorl of tentacles suiTounding the base of
a trumpet-shaped pruboscis.

1 genus : Eudendritwi.

EUDEN'DRIUM, Ehr.— A genus of Hy-
droid Polypi, fam. Eudeudriidas (Tubula-
riidie, Johnst.).

Char. Those of the family.

7 British species.

E. ramosum {Ttibularia rain., Johnst.) is
common on oyster-shells, &c.

BiBL. Hincks, Brit. Zoojjh. 79; Johnstone,
Brit. Zooph. 46.

EUDORI'NA. See Pandobina.

EUGLE'NA,_ Ehr.— A genus of Infu-
soria, of the family AstasiiBa.

Char. Free ; a red eye-speck, a tail-like

process, and a single fiagelliform filament;
freshwater.

Many species, or rather forms, are distin-
gidshed by Ehrenberg and Dujardin. They
are often present in vast numbers in pools,
&c., rendering them green or red, and form-
ing a brilliant pellicle upon the surface.

In the free condition the Euylence swim
about in the water, not apparently by the
help of the fiagelliform filament, which
seems to be often deficient, but by the con-
tractile action of the whole Taody, the changes
of form and movements of which may be
roughly compared to those of a leech when
crawling sluggishly over the surface of a
glass. The Etigleiice present many points of
resemblance to the lower Alga;, especially
Protococcus, like them varying in colour
from green to red, and, moreover, passing
through a resting stage, encysted in a kind
of cell-membrane, which is sometimes gela-
tinous, transparent, and spherical, some-
times rather horny, and polj^gonal in form.
The encysted forms occm' commonly aggre-
gated together into indefinite frond-like
masses ; and the individuals multiply by
division into two, four, &c., in this quiescent
stage. The frond-like groups may be found
in autumn, and even imder the ice in winter,
while the active forms abound most in sprint,
in fine weather. Carter has published some
elaborate observations on the organization
of these and allied forms, which we have
notspaceto enter upon here. (See Astaslea.)
We can only notice two or three of the forms.
E. viridis (PI. 31. fig. 2 a, b). Fusiform
when extended ; head narrowed, short ; tail
conical, short (not cleft) ; green, hyaline at
the ends; length 1-1150 to 1-240".

E. pyrum (PI. 31. fig. 1). Body, when
extended, oval, turgid, pyriform, obliquely
fm-rowed, green ; tail nearly as long as the
body, acute; length l-lloO to 1-860".

E. lonyicauda, Phacus lonyic. D. (PI, 31.
figs. 3 & 63). Depressed, elliptical or oval,
frequently twisted on its long axis, green,
with longitudinal striae ; tail as long as the
bodv, hyaline, subulate ; length 1-280 to
1-120".

E.act(s{V\. 31. fig. 4). Fusiform, slender,
subulate, straight, green in the middle ;
head attenuate, somewhat truncate, hya-
line ; tail very acute, "hyaline : length 1-570
to 1-216".

BiBL. Ehrenb. Infus. 104 ; Dujardin,
Infus. 358 ; Morren, JRuhef. d. Eaux. Brux.
18*41 ; Carter, Ann. N. Hist. 1856, xviii.
115, and 1857, xx. 21 ; Kent, Inf. 379.

EUGLENIA,

[ 306 ]

EUPLOTES.

EUGLE'NIA, Duj. (Infusoria). See

ASTASI^A.

The essential cliaracter of this family is
the presence of a contiactile integument;
this is probably of little importance, as in
many cases the nature of the integument
has been shown to depend upon season,
locaUtv, and stage of development.

EU'GLYPHA, Duj.— A genus of Rhi-
zopoda.

Char. Free ; single ; carapace membra-
nous, transparent, resisting, elongate-ovoid,
iirceolate, covered with rows of tubercles
or depressions ; orifice toothed ; expansions
munerous, simple.

This genus appears unnecessarily sepa-
rated from Diffiugia, E.

E. fMbercuIata (PI. 30. fig. 53). Carapace
covered with oblique or longitudinal rows
of rounded tubercles. Freshwater ; length
1-280". Sometimes posterior spines are
present.

E. alveokita (PI. 30. fig. 54). Carapace
covered Avith polygonal depressions, in re-
gular oblique rows. Freshwater; length
1-280". Posterior spines also present.

See DiFFLUGiA.

BiBL. Dujard. Ltf. 251; Carter, ^«?j. iV".
Hist. 1805, XV. 290.

EUMEEID 'ION, Kiitz. — Consolidated
with Meridion.

EUNO'TIA, Ehr.— A genus of Diato-
macete.

Char. Frustules free, single or binate,
quadrilateral ; linear or linear-oblong in
front view, curved or concavo-convex in
side view ; valves with terminal puncta
(nodules ?) and transverse or slightly ra-
diating striae, but no canaliculi. Fresh-
water and fossil. Allied to Epithemia.

Many of the species have undulations or
ridges upon the convex surfaces; stria3 re-
solvable into dots, but in some species diffi-
cult to detect ; transverse section of frustule
trapezoidal.

Kiitziug describes forty-four species ;
Smith admits seven as British.

E. tetraodon {Himanfidium Mr., K.") (PI.
51. fig. 27: a, side view; i, front view).
Frustules with four ridges ; striae distmct ;
length 1-570".

E. vwnodon {Himant. monodo7i, K.). Side
view lunate, no ridges, sliglitly constricted
near the obtuse ends ; slriie obscure ; length
1-800".

E. triodon. Bidges three; ends attenuate,
rounded; striae obscure; length 1-500".
BiBL. Kiitzing, Bacill. 3(3, and Sp. Al;/.

4 ; Smith, Brit. Dial. i. 15 ; Ralfs, Ann. N.
H. 1844, xiii. 450.

EUXOTOGRAMMA, Weisse.— A genus
of fossil Biatomaceae.

Char. Front view as in Anatdiis', side
\iew lunate, with undulated dorsal and
ventral margins.

E. tri-, qidnque-y septem-, et 7iovemIocidata.
Side view divided by 2, 4, 0, or 8 transverse
septa into 3, 5, 7 or 9 loculi. Russia.

BiBL. Pritchard, In/us. 860; Weisse,
Bull. St. Petersbonrg, xiii. 278.

EUODIA, Bailey.— A genus of Diato-
macefe.

CJiar. Frustules areolar or granular, side
view lunate.

3 species: 2 fossil, 1 recent. Perhaps
Ooniothecia.

BiBL. Bailey, Pritchard's Infus. 852;
Greville, Micr. Trails. 1861, 67.

EUPLEURIA, Am.— A genus of Biato-
maceae.

3 species : New Zealand and Africa (Icha-
boe guano).

BiBi,. Arnott, Qu.Mic.Jn. 1858, vi. 89.
EUPLO'TA, Ehr.— A family of Infu-
soria.

Char. Body surroimded by a carapace ;
two distinct alimentary orifices, neither of
which is terminal ( = Oxytrichiua with a
carapace).

Locomotive organs consisting of cilia,
hooks, claws, or styles. Dujardin states
that the carapace undergoes diffluence like
the substance .of the body.

The genera are thus distinguished : —

Cilia, fArouth )

claws, or J "^. I , ( Head distinot ...Discocephahis.

hooks N fp >f h \ ^o distinct head. Hiininitophoriis.

noTn"es [ Mouth with teeth Chlamidodoii.

Cilia, claws, and styles present Euplotes.

Dujardin includes this family in his Ploes-
conina.

BiBL. Ehrenb. Infus. 374 ; Dujard. Inf.
429.

EUPLO'TES, Ehr. (Ilccscama, Duj., for
the most part). — A genus of Infusoria, of
the family Euplota, E.

Char. Furnished with cilia, styles, and
hooks ; teeth absent.

The species are very numerous.

E. patella, E. (Plcesconmpat., D.) (PI. 31.
fig. 5 : a, under view ; b, side view). Cara-
pace a testa, oval or suborbicular, slightly
truncated in front, margins extending be-
yond the depressed body ; dorsum raised or
bossed •vvith fine radiating striae ; cUia form-

EUPODISCUS.

[ 307 ]

EURYCEROUS.

ing- a curvilinear series; freshwater; length
1-288 to 1-216".

E. cimc.r, E. i^Coccudina cimex, 1).).

E. c/ttirun, E. (Piasconia charon, 1).).

E. vannus, E. {PI. vannus, D.) (PI. 31.
fig. 6).

E. monosfi/his, E. (Ervilia legtimen, D.)
(PI. 30. tig. 52).

BiBL. Ehrenb. Tnfus. 377; Duj. In/us,
435 ; Stein, Infus. 158.

EUPODIS'CUS, Ehr.— A genus of Dia-
tomaceifi.

Char. Frustules single, disk-shaped, cir-
cular, without internal septa ; valves fur-
nished with tubular or spinilbrm processes.
Marine and fossil.

The processes are so easily broken ofF,
that the apertures corresponding to the
points of attachment are generally alone
seen. The valves appear either distinctly
areolar, the depressions being large ; granu-
lar, from their being minute ; or striated.

Two groups are recognizable :

a. Etqwdiscus proper. Valves areolar or
striated.

E. an/us (PI. 16. fig. 30 : a, side view ; b,
front ■S'iew). Valves slightly convex ; pro-
cesses three ; diameter 1-156".

E. sculpfm, Sm. (PI. 16. fig. 31). Valves
striated, central striae forming a quatrefoil ;
processes two ; diameter 1-770 to 1-400".

b. Atdacodiseiis, E. Valves granular ; pro-
cesses veiy short, their bases connected with
the centre of the valve by a furrow.

E. crvx (PL 50. fig. 43). Diameter 1-380".

E. Petersii. Processes four, with larger

granules at their bases. Diameter 1-380".

BiBL. Ehrenb. Ahh. Bed. 1839 ; id. Ber.

1844, 73, 1845, 361 ; Smith, Brit. Diat. i.

24 ; Kiitzing, Sp. Ah/. 134 ; Shadbolt, Qu.

Mic. Jn. ii. ; Roper, 1858, ibid. vi. ; -Gre-

ville, Mic. Trans. 1863, 73, (Aidacodisctts)

1864. pp. 0.82, 87, 1865, p. 26,1866, pp. 5,80.

EUPO'DIUM. — A genus of Marattia-

ceoiis Fems. Exotic.

EURO'TIUM, Lk.— A genus of Pyreno-
mycetes (Ascomycetous Fungi), on the dis-
tinct nature of which great doubt is thrown
by the recent observations of De Bary. E.
hcrbariorum of authors is a mildew, common
upon decaying or preserved fruits, plants
imperfectly dried for herbaria, &c., forming
a whitish or yellow crust, composed of inter-
woven mycelium filaments, which are deli-
cate when young, but become thickened and
often coloured with age. Upon these are
produced globular conceptacles or peridia,
from 1-15 to 1-20"' in diameter, composed

of a distinctly cellular membrane, enclosing
little sacs or asci containing several minute
sporidia. According to De Bary, these con-
ceptacles are produced upon the myceUum
of Aspergillus, under certain unknown con-
ditions ; and the ordinary fructification of
AspergiUm is only a basidiosporous form of
the same plant which produces an asco-
phorous form in the Eurotium fruit. He
states that he not only foimd them grow- ,
ing upon the continuations of the same
branched mycelium filament, but that he
has raised Aspergillus.! which fruited, from
the spores both of Aspergillus fruits and the
sporidia of Eurutinm ; Eumtium could not
be obtained from Aspergillu.s spores. The
connexion between these forms is regarded
as analogous to that between Oidimn and
Erysiphe. The fruit oi Eurotium is a sexual
product, and originates as follows. The
ends of certain branches of the mycelium
coil up like a cork-screw, becoming more
closely approximated, until at length they
come into contact, and form a cylindrical or
conical mass, marked externally by the
spiral lines of conjunction of the turns of
the filament. From the base of this mass
tJiin branches sprout, running up over it, one
of them fusing with its apex, forming an
antheridium or polliuodium, and producing
fertilization. After fertilization, the young
perithecia become segmented, the segments
forming shoots, which branch, the termina-
tions forming the asci or parent cells of the
sporidia. The ripe sporidia often exhibit a
curious form, hke little cylinders with a con-
cavo-convex cap applied over each : these
appear to be the two halves of the dehiscent
outer membrane (e.xosjjore) ; for in the ger-
mination of perfectly globular furms the
mycelium filaments break through the outer
tough coat, like a pollen-tube from the inner
coat of a pollen-grain. The sporidia are
about 1-350"' in diameter, and of a light
yellow colour in mass. The dimensions &c.
of Eurotium, like those of Aspergillus, seem
to vary with the external conditions,

Eurotitmi Bosarium, Greville (Sc. Crypt.
Fl.)=- Spharotheca pannosa.

BiBL. Berk, in Hook. Brit. Fl. ii. pt. 2.
333 ; Greville, Scot. Crypt. Fl. pi. 164. fig.
1; Sowerby (Farinaria), ])1. 379. fig. 3;
De Bary, Bot. Zeit. xii. 425 (1854) ; Riess,
ibid. xi. p. ]34, and Fresenius, p. 474
(1853).

EURYCEROUS, Baird (Z?/«c«<5. in part,
Mull.). — A genus of Entomostraca, of the
order Cladocera, and family Lvnceidse.

x2

EUTERPE.

[ 308 ]

EXPECTORATION.

Char. Subquadrangular (in side view) ;
abdomen very broad, flattened, densely ser-
rated ; beak blunt, slightly curved down-
wards. Freshwater.

E. lamelhdus (PI. 20. fig. 39). Shell olive,
ciliated on the anterior ventricose margin,
arched behind ; beak rather blunt and short;
superior antennae terminating in six short
spines, each with a line seta or bristle ; an-
terior branch of inferior antennte wdth five
long filaments — one from the end of the first
and second joints, three from the third, as
also a small spine ; posterior branch with
three long filaments at the end of the last
joint, the first and second each with a short
spine only.

It generally lives at the bottom of the
vessel in which it is kept.

BiBL. Eaird, Brif.. Entom. p. 123.

EUTER'PE, Glaus.— A genus of Cope-
poda.

1 species: Ireland. (Brady, Coiwpoda,
Bay Soc. ii. 22.)

EUTREP'TIA, Perty.— A genus of Fla-
gellate Infusoria.

Char. Free, ovate, or pyriform, green;
swimming or creeping ; flagella two, equal ;
an anterior red eye-spot.

E. viridis. Length o^o"- Pond- water.

BiBL. Perty, Kl. Lebensf. 1G8 ; Kent,
Inf. 410.

EVADNE, Loven. — A genus of Eutom-
ostraca, of the order Cladocera, and family
Polypheniid^te.

Char. Abdomen short, scarcely projecting
from the shell ; head not distinct from the
body ; marine.

E. Nordmanni (PI. 19. fig. SO). Colom--
less, excepting the eye.

Forms part of the food of the herring.

BiBL. Lov(5n, Wiec/manns Archiv. 1838,
Bd. i. 143; M.-Edwards, Crust, iii. 390;
Baird, Brit. Entom. 114.

EVER'NIA, Ach. — A genus of Lichena-
ceous Lichens, tribe Ramalinei; cosmopo-
litan in its range; recognized by its fiat-
tened, flaccid, laciuiate, white or grey thal-
lus, lateral apothecia, and simple spores.
Two species: E.furfaracea {E. But. pi. 984)
and E. prunastri (E. But. pis. 8o9 «& 1353)
occur in Great Britain.

BiBL. Nylander, Si/n. 283 ; Leightou,
Lich. Fl. G. B. 81.

EXCIP'ULA, Fr.— A genus of Spha-ro-
nemei (Stylosporous Fungi), forming horny
tubercles on dead stems and leaves, finally
o]iening by an entire orbicular apeiture.
The stylosporcs are elongated, lauceolate or

fusifomi; and long hair-like processes are
sometimes mixed with the sporophores
which line the disk. Fom* British species
are recorded : E. fusispora and E. strujosa
of Fries, and E. macrosticha and E. chceto-
stroma of Berk, and Br. Perhaps related
to some Ascomycetous form, (See Gonio-

MYCETES.)

BiBL. Berk, in Hook. Br. Fl. ii. pt. 2,
296 ; Berk, and Broome, Ann. N. H. 1850,
V. 450. pi. 11. fig. 2.

EXIB'IA, Fr.— A genus of Tremellini
(Hymenomycetous Fungi), forming gelati-
nous, truncated black or coloured bodies on
the trunks and branches of trees. Gommon
in autumn and winter. Tulasne has lately
published some interesting observations on
the structure of the hymenium which
clothes the upper face. This is composed
of a densish layer of very slender filaments,
which bear at their free surface globular
cells (basidia) divided vertically into two or
four chambers ; fiom each of these arises a
slender process (sterif/nia), at the end of
which is developed a stylospore. In E. spicu-
losa, spermatia were also observed in young
specimens, at the ends of very slender fila-
ments passing through the mucilaginous
layer overlying the layer of basidia. (See
Backymyces, Hkeneola, and other genera
of Tremellini.)

BiBL. Berk, in Hook. Br. Fl. ii. pt. 2.
217 ; Tulasne, Ann. Sc. Nat. 3 ser. xix. 202,
pis. 11 & 12.

EXOAS'GUS. See Ascomyces.

EXOBASIDIUM, Wor. — The lowest
form of Hymenoniycetes. E. Vaccinii is
common on Ixhodvdendron and Vaccinivm,
causing fleshy swellings on the leaves. It
is Ascomyces carnosa, Berk.

BiBL. Be Barv and Woronin, Ber. Nat.
Gesell. Freiburf/,\x. 397 ; Sachs, Bat. 336.

EXOCOG 'G'US,Nageli.— Probably a P/v-
tococcus or PalmeUa.

BiBL. Niigeli, Netc, Alyensyst. p. 169.

EX'OGEN. See Dicotyledons.

EXOS'MOSE. See Enbosmose.

EXPEGTORATION.— The various ob-
jects which may be fomid in the expectora-
tion are noticed under their respective heads,
■jr those of the tissues from which they are
derived ; a list only need be given here.

Mucous corpuscles ; epithelial cells, of the
pavement, cylinder, or ciliated forms ; exu-
dation globules, or granule-cells ; pus and
pyoid corpuscles ; coloured corpuscles of the
blood ; pseudo-membranous flakes of fibrine ;
tubercle ; fatty matter in the form of glo-

EXUDATION.

[ 300 ]

EYE.

bules, rarely of crystals ; earthy matters,
aiuorphous orcrvstalline ; various substances
derived from the food, as muscular fibre,
starch-granules, cellular tissue, Szc. ; ento-
zoa, or ffagments of them, as portions of the
cysts or hooks oi Echinococcus; infusoria and
alg\T?, as Monads, Bacteria, Sarcina, Sec ;
carbon and true pigment, either in the free
state or contained •vvithin epithelial cells ;
and fragments of pulmonary tissue.

The aid of the microscope in the exami-
nation of the expectoration will occasionally
throw an unexpected light upon the dia-
gnosis of disease. And it
has been shown, that by
boiling- the sputa with
solution of caustic soda
and washing, the pulmo-
nary fibrous tissue may
often be detected in
Phthisis.

EXUDATION, and
EXUDATION COR-
PUSCLES. See In-
flammation.

EXU'VIUM (exuvia;
or exuvise, plur.). — The
cast or shed sldn of ani-
mals. The exuvium of
many minute animals ex-
hibits the form and struc-
tiu'e of the skin, and the
parts upon which it is
moulded, better than
these can be discerned
in the living animals, on
account of its transpa-
rence. The exuvium of
the Triton (PI. 49. fig.
12) exhibits the cellular
structure of the epider-
mis veiy beautifully.

EYE.^ — From want of
space, we are compelled
to assume that the reader
possesses a knowledge of
the component parts of
the eye and their relative
position, as far as can be
obtained without the use
of magnifying glasses.
These parts are generally
described in works upon
anatomy, and in most of
those upon optics.

The outer fibrous coat
of the eye is commonly
regarded as consisting of

single continuous

two parts : one anterior, smaller and trans-
parent— the cornea; the other, posterior
larger and opaque — the sclerotica. The
history of the development and the minute
structure of these prove that they must be
considered as forming a "
membrane.

The cornea may be regarded as consisting
of three layers : — 1, the corneal conjunc-
tiva ; 2, the true cornea ; and 3, the mem-
brane of the aqueous humour.

The corneal conjunctiva (tig. 207, C«) con-
sists of laminated soft epithelium — the

Fig. 207.

Section of the membranes of the eye, near the ciliary processes.

Sc/., sclerotica ; C, cornea; Pr. eiZ., ciliary process ; C a, anterior chamber;
Cp, posterior chamber ; Cr, vitreous humour ; C. P., canal of Petit ; i, lens ;
I, iris : a, conjunctiva of the cornea — epithelial layer; b, subjacent elastic layer ;
c, fibrous layer of the cornea; </, membrane of the aqueous humour; e, its
epithelium ; y, end of the membrane and its fusion with the fibres ,9, which
pass to the iris at i. forming the pectinate ligament; h, venous canal; k,
ciliary muscle arising from the inner wall I of the venous canal ; m, pigment-
layer of ciliary process^es; n, that of iris ; 0, fibKius layer of iris ; p, its epi-
theUum; 5, anterior wall of capsule of lens; s, ep'theliimi of capsule ; ^ ante-
rior thickened portion of hyaloid membrane ; «, zonule of Zinn, or anterior
lamina of hyaloid membrane; v, posterior lamina of the same; «■, colourless
epithelium of the ciliary processes ; ?r', anterior end of this epithelium ;
X, conjunctiva of sclerotica ; z, posterior wall of the capsule of the lens.

Magnified 12 diameters.

EYE.

[ 310 ]

EYE.

under layer of cells elongated and placed per-
pendicularly to the surface, the middle cells
rounded, those in the upper layer forming
softer nucleated plates. Many of the latter
are furuished with larger or smaller depres-
sions, arising from mutual pressure, so as to
appear stellate in the side view. Beneath
the epithelium is a structureless layer (b),
the anterior elastic or Bowman's luembrane,
consisting of the remains of the formerly
vascular layer of the corneal conjunctiva.

The tnte cornea (tig. 207 c), w4iich forms
the principal part of the membrane, consists
of a substance nearly allied to connective
tissue. Its elements are pale bundles ft-nm
1-GOOO to 1-3000" in diameter, with still
finer fibrilL-B, united to form larger lamellar
bundles, the surfaces of which are parallel
to that of the cornea ; these are connected
with the bundles before and behind, so as
to form a coarse reticular tissue. Between
the bundles are a large number of anasto-
mosing, fusiform, and stellate lacimje, with-
in which are contained cell-structures form-
ing the corneal corpuscles. The cells under-
go fatty degeneration, partly _ forming the
arcus senilis ; and they sometimes contain
pigment.

The cornea contains numerous fine nerves,
which ramify nearly to the surface, between
the epithelial cells.

The sclerotica (fig. 207, Scl.) or tunica
alhuginea covers the posterior four fifths of
the ball of the eye ; it is a milk-white, very
firm, fibrous membrane, continuous poste-
riorly with the sheath of the optic nerve,
becoming gradually thinner in front, except
at its termination, 'where the tendons of the
recti muscles become fused with it. It con-
sists of connective tissue, the bundles of
which are mostly straight, intimately united
as in the tendons, forming alternating lon-
gitudinal and transverse layers of various
breadth and thickness. ]\Iingled with the
connective tissue are numerous fine elastic
fibres, in the form of a network, with thick-
enings which indicate the remains of the
nuclei of the formative cells ; these, in the
inner portions, contain pigment. _ During
life, the elements of this network, in parts,
appear to involve canals with liquid con-
tents ; so that, when dried, they contain air.

The membrane of the aqueous Jnimour
(fig. 207 d) consists of an elastic, perfectly
structureless (Descemet's) membrane, some-
what loosely connected with the cornea, and
an inner epithelial fining. Towards the cir-
cumlereuce of the cornea, the membrane of

the aqueous humour merges into a peculiar
system of fibres, which Ci.mmence ni.'ar tlie
margin of the cornea, at the anterior surface
of the aqueous membrane (fig. 207//) a-; an
extended network of fine fibres, resembling
elastic fibrilloe ; this increases in thickness,
and at the very margin of the cornea the
aqueous membrane becomes lost in a tole-
rably dense network of these fibres, which
curve around the margin of the iris (fig.
207■^), some passing through the anterior
chamber, and become fused -^-ith the ante-
rior surtiice of this membrane and the ciliaiy
ligament (or muscle). These fibres form
the pectinate lic/ament of the iris, which is
much more distinct in some animals (as the
dog) than in man.

The epithelium {e) of the aqueous mem-
brane consists of a single layer of polygonal
cells. These become smaller near the mar-
gin of the cornea, where the membrane ter-
minates as a continuous layer ; but isolated
portions of elongated or spindle-shaped cells
are continued over the pectinate ligament
to the anterior sm'face of the iris.

The cornea yields choudriue on boiling,
and not gelatine.

The cJioruid membrane contains a large
number of blood-vessels, and abounds in
pigment. Its anterior, smaller, and trans-
verse portion / forms the iris.

The posterior portion, or proper choroid
membrane, is from 1-360 to 1-180" in tliick-
uess, and extends from the entrance of the
optic nerve to near the anterior margin of
the sclerotica, where it becomes thicker,
forming the ciHary body, whence it is con-
tinued into the iris.

The choroid consists essentially of two
parts : — an outer vascular and thicker layer,
the proper choroid ; and an inner deeply
coloured layer, the j)i(imentum nif/rnm.
The former may again be separated into
three parts, although these are not really
distinct : — 1, an outer, brown, soft layer,
which supports the ciliary nerves and long
ciliary vessels, and contains anteriorly the
ciliary ligament — the outer pigment layer ;
2, a less highly colom-ed proper vascular
layer, with the larger arteries and veins ;
and 3, a colourless delicate inner layer,
containing an extremely copious capillary
network — the choro-capillary membrane,
which docs not extend anteriorly beyond
tlu! margin of the retina. The stroma of
tlie clioroid proper consists of very irregular
spindle-shaped or stellate cells, from l-loOO
to 1-GOOO" in length, either paler, or con-

EYE.

[ 311 ]

EYE.

Fig. 208.

taining a large qiiantity of pigment, and
ana.stoniosing by nuinovdus long and very
slender processe^s (tig. 208). These cells are
most distinct in the
outer layer ; whilst
more internally, and
especially in the oho-
ro - capillary mem-
brane, they gradually
pa^ss into a homoge-
neous or slightly stri-
ated nucleated tissue,
containing but little
and ultimately no
pigment.

In some animals
the choroid mem-
brane contains mus-
cular fibres. Cells from the stroma of
Tj , ^' ,1 . the choroid; a, eontaining
±5et\veeu tne Stro- pigment; b, fusiform cells
ma and the pigmen- without pigment ; e, ana-

turn nigi-um is a very ^^^l^^^^l
thin elastic layer ;

this is either structureless, granular, or finely
reticulated, and is comparable to a base-
ment membrane.

The ciliary muscle — tensor choroidecs (fig.
207 k) — is composed of a tolerably thick
layer of radiating uustriated muscular
fibres ; these, intermixed with pigment-
cells of the choroid, pass from the anterior
margin of the sclerotica to the ciliary body,
and lose themselves in its anterior half,
opposite the base of the ciliary processes.
The fibre-cells are 1-600" in length, broader
than most fibre-ceUs, and not easily isolated
in man.

The ciliary processes consist of the same
stroma as the choroid ; but the stellate
cells are more delicate and fewer, and, with
the exception of those at their base, do not
contain pigment ; nor are they furnished
with the elastic lamina.

The piymentum nif/riwi (fig. 207 ?/?) lines
the inner surface of the choroid, and as far

Fig. 209.

#

<,?',

Cells of the human pigmentum nigrum: a, surface
view ; 6, side view ; c, pigment-gi-anuies.

Magnified 350 diameters.

as the termination of tlie retina, consists of
a single layer of beautiful, regularly six-
sided cells (fig. 209 a, b), from 1-2000 to
1-1500" in diameter ; tlicy contain abiuid-
auce of pigment. Beyond the margin of
the retina, the cells form mostly two layers,
and become rounded and more loaded with
pigment. The granules of pigment are
very minute, rounded, from 1-20,000 to
l-.30,000" in diameter, and exhibit mole-
cular motion. In the eyes of albinos, and
in the region of the tapetum of animals, the
cells contain no pigment.

The iris (fig. 207, I) consists of three
layers :— an anterior epithelial layer ; a pos-
terior layer of pigment, called the uvea, and
continued from the inner pigment layer of
the choroid ; and a middle, the thickest or
fibrous layer.

The fibrous layer difiers fi-om the choroid,
in containing connective tissue forming deli-
cate loose bundles, some of which pursue a
radiating, others a circular course, and in-
terlacing variously ; in this tissue are a
number of spindle-shaped or stellate cells,
containing pigment, corresponding to those
of the choroid, and in addition to nume-
rous blood-vessels and nerves, two sets of
muscidar fibres : the latter in some animals
are transversely striated ; but in man they
resemble the ordinary unstriped fibre-cells,
and are 1-600 to 1-400" in length. One set
forms a sphincter for closing the pupil, its
fibres taking a circular direction ; the other
set consists of bundles of radiating fibre-
cells, traversing the stroma of the iris. The
pigment layer or uvea consists of the same
elements as those of the corresponding layer
of the choroid.

The anterior coat consists of a single layer
of rounded, flattened epithelial cells.

The blood-vessels of the choroid mem-
brane and cihary processes are easily injected
(e. y. in the sheep or ox) from the ciliary
arteries, and form a magnificent object.

The retina is the terminal membranous
expansion of the optic nerve within the
globe of the eye. • It consists of nerve-cells
and fibres, imbedded in a spongy supporting
connective tissue.

Nine layers are distinguishable in a
transverse section of the retina (fig. 210),
commencing from within : viz. 1, the inter-
nal limiting membrane (b) ; 2, the layer of
optic nerve-fibres (r7) ; 3, a layer of nerve-
or ganglion-cells (?) ; 4, a molecular layer ;
5, an inner gi-anular layer (/) ; 6, an inter-
mediate granular layer \y) ; 7, an outer

EYE.

[ 312 ]

EYE.

granular layer (7i) ; 8, a narrow outor limit-
ing membrane ; and 9, the layer of cones
({), and bacilli (k). The pigment-cells
of the choroid membrane are also some-
times considered a layer of the retina.

Fiff. 210.

ffwrnmrTiT^T^miTTTTriTTiniTiiii'

Perpendicular section of a piece of the posterior part
of the human retina.

a, hyaloid membrane with nuclei ; 6, internal limiting
membrane ; c, ends of the radiating fibres, so altered
as to present a cellular appearance; d, layer of
optic nerve-fibres: e, layer of nerTe-cells; /, inner
granular layer ; g, intermediate or finely granular
layer, in which the radiating fibres are more distinct
than elsewhere; %, outer f(ranular layer; i, inner
division of the layer of bacilh, with the cones ; k, outer
division, with the processes of the cones and the true
bacilli.

Magnified 350 diameters.

The internal limiting membrane (?;) is an
extremely delicate structureless iilin, cover-
ing the inner surface of the retina, including
the entrance of the optic nerve, and the
macula lutea.

The expansion of the optic nei-ve forms
a membranous layer of extremely delicate
transversely radiating fibrils (fig. 211, S),
from 1-24,000 to 1-12,000" in diameter,
and mostly exhibiting varicosities. They
contain no nuclei, and appear to consist of
the axial fibres only. They are aggregated
into flattened bundles which either run
parallel or anastomose with each other.
They are absent, or at least as a coherent
layer, opposite the macula lutea,

'The layer of nerve-cells {e) consists of
ordinary norve-cells, pyiiform, roundish, or
angular, with pale processes ; they vary in
diameter from 1-3000 to 1-750".

The molecular layer lies between the
ganglion-cell layer {c) and the inner granular
layer (/■). The outer limiting membrane
is" situated between the outer granular
layer (A) and the layer of cones and bacilli
ii).

The remainder of the retina is mainly
composed of a verv large number of parallel,
very slender (1-60,000 to 1-20,000" diame-
ter), highly refi-active, radiating fibres or
tubes (^1 tiller's fibres), with their axes at
right angles to the sm-face of the choroid,
upon which their outer ends rest, whilst
their inner, triangular or branched ex-
tremities are in contact with the limiting
membrane. They produce the striated
appearance presented by a section of the
retina (fig. 210). They are furnished at
certain parts of their course with expan-
sions containing each a nucleus ; and the
fibres are very numerous. These nucleated
expansions being opposite each other, or in
the same planes, give rise to the appearance
of distinct granular layers mentioned above.
The more internal nucleated expansions are

Fig. 211.

Elements of the himian retina. 1. Radial fibres vrith
bacilli : A-, bacillus, connected with the fibre (c) br its
inner acute end ; A, nucleated expausion (cell), appear-
ing in the outer granular layer ; /, ex))anded end of the
fibre, resting upon the limiting membrane »i ; k\ a
bacillus connected with a cone i ; r', fibre running from
the cone to the celiy of the inner granular layer ; n,
branched termination of a radial fibre, often present.
2. Bacilli separated from the fibres, broken and curved,
&c. ■ 'A. Fibrils from the expansion of the human optic
nerve : n a, larger, b, smaller, fibrils with varicosities ;
c, undulating pale fibres belonging probably to the pro-
per radiating system. 4. Two cones connected with
bacilli, and fragments of the fi.bres remaining : a, ba-
cillus ; b, cone ; c, nucleus of cone.

Magnified .350 diameters.

EYE.

[ 313 ]

EYE.

coimectod with the nerve-cells of the retina
by minute nerve-tubes.

Their outer portions have been distin-
guished as the haciUi and cones; but the
vehole probably form one continuous system
of nerve-cells and tubes.

The haciUi, regarded (fig. 211, 1 h k', 2) as
distinct bodies, are cylindrical, narrow and
elongated, of the same breadth through-
out, truncated externally, and terminating
internally in a more slender portion of the
fibre ; they are from 1-4-30 to 1-330" in
length and 1-15,000" in breadth ; near the
point of attachment to the fibre is a trans-
verse line. They are extremely delicate,
and easily broken or deformed. The cones
(fig. 211 i ^, 4 ^) are bacilU with a conical
or pyriform body, and are also very easily
inj ured. A slight constriction divides each
cone into two parts, the innermost of which
(tig. 211 Ji c) contains a nucleus. The cones
are from 1-GOOO to 1-4000" in diameter.
In most parts of the retina the cones are
surrouuded by several bacilli ; opposite the
macula lutea they alone form a continuous
layer ; whilst at its margins, single bacilli
intervene between the cones (fig. 212).

Fig. 212.

End view of the rows of bacilli and cones from the
ontside. 1, opposite the macula Intea, cones only ;
2, at its margins ; 3, at the middle of the retina, a,
cones or spaces corresponding to them ; b, bacilli of the
cones, the ends of which are often situated somewhat
beneath the level of those of the true bacilli, e.

Magnified 350 diameters.

Opposite the entrance of the optic nerve,
both bacilli and cones are absent. These
curious bodies are more distinctly seen in
many animals than in man (PI. 50. fig. 5),
and they present certain varieties: thus,
the cones are deficient in bats, the hedge-
hog, the mouse, the mole, and the sharks
and rays ; while the bacilli are deficient in
the reptiles.

The inner ends of the radiating fibres
when overlapping each other, and especially
when swollen by the action of water,
present the appearance of a number of

rounded or angular cells (fig. 210, c), for
which they were once mistaken.

It is thus evident that, excepting the
layer of nerve-cells and that of the fibres of
the optic nerves, the retina cannot truly be
considered as composed of layers. The
series of bacilli and cones, when torn from
their connexion with the radial fibres, form
the so-called Jacob's me7nbrane.

Between the nerve-fibres, from the outer
to the inner limiting membrane, lies the
connective supporting tissue ; this also
forms a considerable portion of the mole-
cular and granular layers. In modem
works, the fibres of this tissue are called
Miiller's fibres. But KoUiker has shown
that the true radiating or Miiller's fibres
are not dissolved by boiling, and are coloured
red by Schultze's test; so that they have
not the chemical composition of connective
tissue.

We cannot enter into the physiology of
these radial fibres, which have been shown
to be the percipients of light.

Crystalline lens. The crystalline lens is
contained in a capsule (fig. 207 q s), con-
sisting of a perfectly structureless, very
elastic membrane, the anterior half of
which is lined with a single layer of very

Fig. 213.

Fibres or tubes of the lens of the ox.
Magnified 350 diameters.

EYE.

[ -314 ]

EYE.

transparent, polygonal, epithelial cells (fig.
207, s), from 1-2000 to 1-1200" in diameter.
The lens itself consists of long, transpa-
rent, six-sided, flattened fibres (fig. 213),
fi-om 1-4800 to 1-2400" in breadth and
l-Srm to 1-13,000" in thickness ; these are
tubular, at least in the outer portions of the
lens, and contain a tenacious sarcodic sub-
stance, which escapes from the ends of the
broken fibres in irregular globules. The
form of the fibres is best seen in a transverse
section (fig. 214).

Fig. 214.

Transverse section of the fibres or tubes of the hu-
man lens.

Magnified 350 diameters.

The fibres are iirmer, narrower, and more
highly refractive towards the centre of the
lens. Their general arrangement is such
that their broad surfaces are parallel with
the surface of the lens, and that they fol-
low a direction from the middle oi the
anterior to that of the posterior surface,
curving laterally in their course — not, how-
ever, exactly from the middle, but from
the arms of a star-shaped kind of centre,
at which parts (fig. 215) the fibres are

Fig. 215.

Anterior view of ln.,i,.iii . i-ywUilline lens (adult),
ehowing tlie stara and the direction of the fibres.
Magnified 5 diameters.

replaced by a homogeneous or finely gra-
milar matter. The arms of the star present
upon the surfaces are the extremities of
planes extending through the substance of
the lens, from which the inner fibres take
their origin. The arms of the anterior and
posterior stars are not parallel with each
other ; nor are the fibres arising from any
part of the arm of one cross inserted into
the corresponding part of the arm of the
opposite cross. Great variety exists in dif-
ferent animals in the structure and arrange-
ment of these stars and planes. Thus in
the human foetus the star has three arms or
planes, whilst in the adult there are fri)m
nine to sixteen, of which three are frequently
more distinct than the others. In some
animals they are replaced by a pole, from
which the fibres radiate like meridians, as
in the cod, the Triton, and Salaviandra ; in
others, there is a single plane, as in some
fishes, the frog, the hare, the rabbit, and the
dolphin ; whilst in most of the mammalia
there are three, and in the whale, the bear
and the elephant there are four.

The edges and marginal surfaces of the
fibres of the lens are uneven or toothed, so
that their lateral connexion becomes more
intimate ; hence the lens separates more
readily into parallel laminae in the direc-
tion of the siu-face than in the opposite
direction.

In many animals, especially fishes, as the
cod, the roach, &c,, the irregulariti(>s of the
fibres of the leus are replaced by beautifid
teeth (PI. 50. fig. G).

Vitreous humour, or body, is enclosed in
a membrane, the hyaloid memhrani', which
behind the dentate margin of the retina is
extremely thin and delicate ; anterior to this
it becomes firmer (fig. 207 t) and passes,
formiug the zonule of Zinn, to fuse with the
capsule of the lens. In thus doing, it sepa-
rates into two layers: — a posterim* (v),
which becomes consolidated with the cap-
sule of the lens somewhat behind its mar-
gin ; and an anterior (u), connected with the
ciliary processes, which becomes attached
to the capsule of the lens, a little in front
of its circumference : between these two is
the canal of Petit {C, P.). The posterior
layer is sometimes considered as arising
from a condensation of the tissue of the
vitreous humour. The structure of the
vitreous body is still obscure.

Th(! structure of the eye is very difficult
of examination, the parts being so delicate
and easily injured. Many of them can be

EYE.

[ 316 J

FASCDE.

made out by dissecting the eye under water ;
but the more delicate ,><tnictures sbould be
immersed in the liquid of the anterior
chamber. Solution of chromic acid and
alcohol is useful for hardening the parts to
allow of sections being made with a Valen-
tin's knife. The cornea may be hardened
in chromic acid, sections cut in parafhne,
and stained with logwood. The nerves and
corpuscles are best stained with nitrate of
silver or chloride of gold. The retina may
be hardened in chromic acid and spirit,
and the rods and cones in osmic acid,
sections being made by freezing ; logwood
stains the granular layers, the rods and
cones remaining unaltered. The lens should
be hardened, either by maceration in solu-
tion of chromic acid, or by drying. The
fibres may be well preserved in the dry
state.

The structure of the eyes of the lower
animals is briefly noticed under the classes,
&c. In the mammalia generally, it is
essentially the same as in man ; and the eye
of the ox or sheep may be selected for
examination.

BiBL. Kolliker, Mik. An. ; Todd and
Bowman's Fliys. of Man ; MliUer, H.,
Comptes Bendus, 1856, 743 {Ann, N. H.
1856, xviii. 492) ; Nunneley, Qu. Micr.
Jn. 1858, 136 ; Schultze, An. unci P/n/s. d.
Retina (8 pi), 1867, & Strieker's Handhiich,
976 ; Hulke, Mn. Mic. Jn. ii. 227, Phil. Tr.
cv. 109; Lawson, Ciliary Muscle of Birds,
ibid. ii. 204 ; Frey, Histol.,^ 1876, and the
fuU literature therein ; Klein, Histol. 342 ;
Hannover, Ret. de Vhomme et d. Vertcbr.,
1877; Gerlach, An. mensch, Auge, 1880 ;
Eloni, Cornee d. an. vert. 1881.

EYLAIS, Latr. — A genus of Arachuida,
of the order Acarina, and family Hy-
drachnea.

Char. Palpi longish, fourth joint longest,
the fifth obtuse, somewhat tumid, spinous ;
mandibles uuguiculate ; rostrum very short,
mouth roimd ; body depressed ; two ap-
proximate pairs of eyes ; coxfe compara-
tively narrow, the fourth only in contact
with the third at its base.

E. extendens (PI. 6. fig. 28). Sldn soft,
furrowed, with the ramified alimentary canal
visible through its substance. Between the
two anterior coxse (d) is seen the bilobed
labium {a), the posterior portion containing
the round and ciliated mouth, the anterior
portion furming a kind of hood ; palpi (b)
with the three first joints very short; man-
dible consisting of a long thick joint, with

a tliick mobile claw (c). Fig. 28 d, under
surface of body, exhibiting from betoro
backwards: — the mouth, with the hood, aiid
the palpi ; next two groups of anterior coxae ;
the vulva and two stigmata ; the four pos-
terior coxte ; and, lastly, the anus in the
middle, with a stigma on each side.

The larva3 are hexapod, reddish, pellucid,
with the eyes four, wide apart.

R. confnis, K.

E. atomaria, K.

BiBL. Duges, Ann. Sc. Nat. 2 ser. i. 156 ;
Gervais, Walcken. Arachnid, iii. 207 ; Koch,
Ueutschl. Crustac.

FABULARIA, Defrance.— A porcella-
neous Foraminifer, growing like a Bilocu-
lina, but having its chambers fiUed with
labp'inthic shell-matter, the cavities in
which are mostly elongate with the axis
of the shell. They are narrow, and, open
ing terminally, make a cribriform septal
face.

Quinqueloculina saxorum has thickenings
within, making internal grooves and ridges,
thus verging on the Fabularian type ; and
Hanerina has a cribriform septal plate, but
without superadded internal structure.

Fahularia ovata (De Roissy), known also
as F. discolithus of Defrance, abundant in
the Eocene Tertiaries of France, is the only
known species.

EiBL. CaiiDcnter, Introd. Fui-am. 82.

FADYE'XIA, Hook.— A genus of As-
pidiese (Polypodiaceous Ferns) ; 1 spec,
Brazil.

F^CES.— We shaU not dwell upon the
nature of the objects contained in the faeces ;
suffice it to say that they may consist of :
— the elements of the various secretions
poured into the intestinal canal ; the pro-
ducts of inflammation ; undigested remains
of articles of food, or bodies taken with the
food or drink ; and entozoa {Anchylostoma,
AnguiUida,Tri€hoce2^hahis),Ama;b(P,Bacteria
&c. Some of these resemble other bodies
very closely to the naked eye. The use of
chemical reagents should never be omitted
in their examination.

FARPtEL'LA, Ehr.— A genus of Cteno-
stomatous Polyzoa, fam. Vesiculariida^.

F. repents ; no gizzard; on shells, algae &c.
(Hincks, Pohjzoa, 528.)

FASCIA.— The fasciae consist of the
same elements as Aeeolar Tissue, and

FATTY DEGENERATION. [ 31G ]

FEATHERS.

present all the varieties of arrangement in-
termediate between it and Tendon.

FATTY DEGENERATION. See De-
generation, Fatty.

FATTY TISSUE, or Adipose Tissue.
— This is formed of colourless cells, with a
very delicate, transparent, structureless cell-
wall, enclosing, in the normal state, glo-
bules of yellowish fat (PI. 49, fig, 41 ). The
cells generally occur in groups, surrounded
by or imbedded in connective tissue. They
are rounded when isolated, or polygonal
when aggregated, and from 1-800 to 1-300"
in diameter ; and the fat so fills them,
that neither the nucleus which they contain
nor the cell-wall is visible. The fat may
be removed by drying them, and digesting
with ether, when the cells appear contract-
ed and wrinkled. In emaciated and drop-
sical subjects, each cell contains a number
of small globules of fat, frequently of a
reddish colour (PI. 38. fig. 3), together with
serum, and the nucleus is very distinct.
Sometimes in these cases the cells are some-
what spindle-shaped or stellate. The fat con-
tained in the cells is ordinarily in a liquid
state ; but sometimes the margarine separates
in the crystalline form (PI. 11. fig. 15 a).

In the mammalia generally the fatty
tissue occurs in the same localities, and has
the same structure, as in man. In fishes,
the fatty matter is deposited principally in
the liver. In reptiles, it occurs chiefly in
the abdomen : thus in the frog and toad it
forms long appendages occupying the sides
of the spine. In birds, it exists chiefly be-
tween the peritoneum and the abdominal
muscles, and in some of the bones. In many
of the lower animals it appears to exist in
the state of solution only.

Fatty tissue is formed from connective-
tissue cells.

Fatty matter may be deposited in cells
of all kinds, as in fatty degeneration.
During the development of cells, it exists in
solution. The action of solution of potash
is often of service in distinguisliiiig globules
of pi\)toplasm, which have a high refrac-
tive power, and much resemble those of
fat, from this substance, as it dissolves the
former, but not the latter ; solution of osmic
acid renders fat-globules black.

J5inL. Todd and JJowman, Flti/s. of Man ;
Kiilliker, Mik7: An. ; Klein, Hist. 42 ; Frey,
Hist.

FAUJASINA, D'Orb.— A delicate and
handsome Foraminifcr, but not typical.
F. carinata, D'Orb., found in the Maes-

tricht Chalk, is a thin asymmetrical (plano-
convex) Poli/stomella, somewhat thinner or
flatter than P. maceUa (F. & M.), which is
a subcomplanate, perhaps starved, variety
of P. crispa (Linn.),

BiBL. Parker and .lones, Ann. N. H. 3 ser.
V. 104 ; Carpenter, Introd. 213, 286.

FAVEL'LA.— A form of the concepta-
cular fruit of the Florideous Algpe, where
the spores are collected in spherical masses
situated wholly upon the external surface of
the frond, as in Ceramium and Callifhamnion,

FAVELLIDTUM.— A form of the con-
ceptacular fruit of the Florideous Algte,
where the spores are collected in spherical
masses attached to the wall of the frond or
imbedded in its substance, as in Hahjmenia
and Dumontia. The term is usually ex-
tended to similar fruits not perfectly im-
mersed, e. g. those of Gigartina, Gelidium,
&c., where they form tubercles upon the
branches. Sometimes these tubercles open
by a pore on the surface, when mature, to
emit the spores.

FA'VUS (Pon-igo in part, Willan and
Bateman). — A disease of the skin, character-
ized by the presence of cup-shaped isolated
or aggregated crusts, consisting of a Fungus.
(See AcHORiON.)

FEATHERS or Birds.— Feathers agree
in all essential points of structure with the
hairs of other animals.

Each feather is composed of a quill (con-
taining the pith), a shaft, and a vane or
beard with its barbs. The whole consists
of a number of epidermic cells, often con-
taining pigment, but in most parts so con-
solidated or fused together as to be imper-
ceptible.

In the quill, the cells are flattened, elon-
gated, and arranged with their long axis in
the direction of that of the feather, and
their nuclei have the same form as those
of the corresponding part (cortex) of the
human hair. The cells of the pith are often
undistinguishable in old feathers, whilst in
the younger ones they are veiy distinct,
rounded or polygonal, and contain air. Tlie
sliaft and the barbs exhibit the some cortical
and medullary structure ; the latter is often
beautifully distinct (PI. 22. figs. 14 & 15 c),
and causes them to resemble closely the
hairs of some Rodents. The barbs are some-
times furnished with secondary barbs, or
barbules, resembling them in form, but dif-
fering mostly in the absence of the pith.

Featliers are diiveloped in a capsule, and
from a pulp or matrix, as in the case of

FEET.

[ 317 ]

FERMENTATION.

hairs. Hence a feather may bo reg'arded
simply as a hirge, doubly or triply pimiate
hair.

Durinj? development, the cell structure is
very distinct ; but in the mature feathers,
digestion with solution of caustic potash is
requisite to render this visible; and fre-
quently even under these circumstances, the
nuclei alone can be detected.

The barbs of some feathers resemble the
shafts', being rounded or angular, and free
or unattached (figs. 17 & 18) ; but in others
they are flattened, and hnked together in a
remarkable manner, much resembling that
met with in the wings of Hymenopterous
and other Insects (PL 34. figs. 11 & 13), and
which has been so often adduced as one of
the many wonderful instances of design in
the creation. Thus the upper or outer
margin of each barb is fi'inged on both sides
with hair-like elongated processes or pinnse
(PI. 22. fig. 15 a, U), which difler in struc-
ture ou the two sides. On one, and this
always the same side of each barb (fig. lob),
the piunfe are toothed ou one edge (fig. 166*),
whilst the pinnfe arising from the other side
(fig. 15 c) exhibit, beyond the middle, a
number of curved hooks (fig-. 16 a), which
clasp around the first kind existing upon
the adjacent barb, so as to retain a firm hold
upon them, this being aided by the teeth,
wJiich prevent them from slipping. If the
relative position of the two sets of piunee
which spring from two adjacent barbs be
examined, it will be seen that they cross
each other at a considerable angle, so that
any pinna from one barb crosses several of
those belonging to the next barb. Hence
each pinna is connected by its hooks with
several of those which it crosses ; for the
pinnas with hooks are situated outside or
above those not furnished with these ap-
pendages. The imder or inner margin of
each barb is simply membranous, and curved
so as to overlap that of the next.

The free barbs of feathers are often met
with in the examination of liquids &c. left
exposed to the air (figs. 17 & 18).

BiBL. Schwann, Mik. Unfersvch. ; Re-
clam, De Plamar. Evulut. ; Leydig, Histol.
99 ; R. Beck, Achr. Micr. 31.

FEET. — In descriptions, &c., of the Arti-
culata, especially of Insects, the word feet
is mostly used to designate the legs ; hence
when met with in the works of systematic
and other writers on these classes, it must
be understood to mean the legs.

FEET OF Insects. See Insects, Legs.

FEGATEL'LA, Raddi {Conoccphalm,
Hill). — A genus of Marchantiaceous llepa-
ticoe. F. conica (Marchuntia conica, Brit.
Fl.), the only British species, is not un-
common, and is one of the largest of the
tribe. It is distinguished from Marchuntia
by its nearly entire conical fertile receptacle.
The dichotomously divided frond is of a
yellowish green colour. This genus is re-
markable for the mode in which the pedicel
of the sporange becomes detached from the
base of the epigone before the former bursts
(fig. 220) ; the perigone holds the sporange
firmly between its valves until empty, and
then lets it fall out, together with its pe-
dicel. Hence fully-developed sporanges
are seldom found in dried specimens. (See
Mahchantie^.)

Fig. 219.

Fig. 220.

Fegatella conica.

Fig. 219. Vertical section of the upper part of a fer-
tile receptacle, showing four of the sporanges sur-
rounded by their perigones and epigones almost en-
closed in the conical recejitacle. Magnified 10 diama.

Fig. 220. A sporange just before bursting, enclosed in
its epigone; its pedicel detached at the base. Magn.
20 diama.

BiBL. Hooker, Brit. Fl. v. pt. 1. 107 ; Bis-
chofl:. Nova Acta, xvii. 970, pi. 68 j Engl.
But. pi. 504.

FEL'SPAR. See Rocks.

FEL'STONE. See Rocks.

FENESTRELLA, Grev.— A genus of
Diatomaceae.

Char. Frustules fi'ee, disciform ; disk with
minute radiant dots, interrupted in the
middle by a transverse band, composed of
parallel lines of dots, baud terminated at
each end by a fiat ocellus (nodule).

F. barbadensis. Barbadoes deposit.

BiBL. Greville, Micr. Tr. 1863, p. 67.

FERMENTATION.— Under this name
are understood vafious processes of decom-
position of organic compounds; although
it would be desirable to restrict it to those
taking place with the cooperation of living
organisms. The most familiar examples of
the fermentation produced by the growth

FERMENTATION.

[ 318 ]

FERMENTATION.

of li%d!ig organisms, are those which convert
saccharine infusions into spirit, vegetable
juices into beer, wine, &c., or vinegar ; and
occur generally in watery solutions of vege-
table substances containing saccharine mat-
ters or other ternary compounds with a
certain amount of nitrogen ; with these is
included also tlie putrefactive fermentation
of moist animal or other highly nitrogenous
substances.

Much obscurity still prevails upon this
subject ; but all investigations appear to
tend in the direction of proving that these
changes are absolutely dependent upon the
agency of Fungi ; and that each kind
of fermentation is produced by a distinct
vegetable organism. Thus : the vinous fer-
mentation appears to depend entirely upon
the growth of Yeast, a microscopic fungus,
in the liquid (see Yeast) ; while milk-fer-
mentation is caused by Bacterium lineola ;
butp'ic fermentation by Bacillus subtilis &c.
Yet, according to the experiments of Muntz
and Pasteur, it appears that the living cells
of the higher plants, can in the absence of
oxygen, act like fungi, and produce a true
iutrocellular alcoholic fermentation. The
Y'east-plant as ordinarily known, appears
so associated with Penicillium, that there
seems no doubt as to the necessary relation
between them. We find that beer, exposed
to the air at ordinary summer temperatures,
soon becomes coated with the minuter glo-
bules (conidia) of Yeast, forming a dry-
looking whitish powder over the surface ;
and very soon after, Penicillium glaucinn
makes its appearance in fruit. Turpin found
the same thing in milk. Again, the * vine-
gar-plant,' as it is called, which converts
solutions of sugar into vinegar, seems to be
undoubtedly the mycelium of Penicillium
glaucum, as it fructifies with the characters
of this when the liquid is exhausted ; but
the gelatinous mass of mycelium contains,
intermixed with the ordinary filaments of
this genus, spherical and elliptical cells and
chains of cells of all sizes, many of which
are undistinguishable from the Yeast-plant,
and the mycelium of Oidium. It must be
recollected also, that the growth of true
Yeast is favoured by a certain amount of
heat, while the Pe«jcj7/m??i-mycelium grows
luxuriantly at ordinary temperatures. Dead
Yt>ast causes no fermentation.

The ' mother ' of vinegar, which finally
decomposes the acid, appears to be the same
plant ; and no satisfactory distinction can
be drawn between this and those mycelia

forming cloudy flocks in and decomposing
various saline solutions, &c., described as
species of Ilyejrocrocis^ Leptomitus, &c. The
decay of wood, again, is often greatly ac-
celerated by the growth of the mycelium
of Fungi, which seems to decompose the
organic compounds in the wood in the same
way that the Yeast does those in organic
liquids. A general law indeed appears to
prevail throughout the Fungi, that their
nutrition differs from that t)f all other plants
in depending exclusively on the absorption
and decomposition (with the evolution of
carbonic acid) of organic compounds, there-
fore consisting of the performance of the
operation of fermentation on the organic
matters upon which they feed. Details upon
the microscopic phenomena attending fer-
mentation produced by Fungi will be foimd
under Yeast, Vinegae-plant, Tokula,
Penicillium, and Schizomycetes.

The fermentation of animal substances,

and of vegetable substances

containing

abundance of nitrogen, in which ammonia
is liberated, is genex&lly cviWe^ put)-ef action,
or ih& putrefactive fermentation. This pro-
cess has been shown to be produced by the
growth of living organisms resembling those
causing the fermentations alluded to in the
foreo-oing paragi-aphs ; and when the organic
liquids are thoroughly boiled and sterilized,
they may be kept indefinitely without
change. These organisms appear in myriads
during the decomposition which takes place
when a piece of meat, &c., shces of potato,
fleshy Fungi, &c., are kept moist and ex-
posed to the air for some days in wai-m
weather; and they continue to multiply
until the putrefaction is complete, when
they die away. It is a question perhaps
whether they liberate the ammonia and
carbonic acid by a kind of respu-ation while
living, or as an excrement.

One point of interest connected with the
fermentation-plants must not be passed
over, viz. that the supposed distinction be-
tween the chemical processes of nutrition
in animals and plants, falls to the ground
when these Fungi are taken into considera-
tion : as thev do not live by converting in-
oryanic substances mto organic compounds,
but, like animals, decompose readv-formed
organic compoumds into others kud into
their inorganic elements.

BiBL. Turpin, Mem. Museum, 1840 ; Bail,
Flora, 18-37, 417 ; Mulder, ■ Chem. of T'eg.
and An. Phys. ; Liebig, Lett. Chemistry,
1231; Gmelin, Organ. Clam.; Lowig, Chein.

FERNS.

[ 319 ]

FERNS.

org. Verb. i. 22.3 ; Mitscherlicli, Poc/ff. An-
nal. Iv. 224 ; Lehrb. 4. ed. .371 ; Cagniard
Latoiir, Pof/g. Ann. xli. 19^ ; Schwann,
ibid. 184 ; \}vQ,BiUioth. Genev. 1839 ; Helm-
holt z, Midler's Archiv, 184-3, 4-53; Reess,
Akohohfiihrunqs - Pilze, 1870 ; Pasteur,
Etudes 's. I. Vmaiffre, 1868, s. I. Tin, 1872,
8. 1. Biere, 1870 ; V. Tieghem, Atin. Sc. Nat.
Tiii. 1868; Fremy, Gcner. d. Ferments, 1875;
Schutzeuberger, Ferment. 1875; Gayon,
Ann. Sc. Nat. 1875, i. 5 ; Muntz, Ferment,
Compt. Bend. 1878 (Jn. Mic. Soc. 1878,
23) ; Lister, Qu. Mic. Jn. 1878, xviii. 177 ;
Niigeli, Theor. d. Gdhrung, 1879 ; Sachs,
Bot. 254 ; Tyudall, Putrefaction ^c. 1881.
See also Torula and Pexicillium.

FERNS.— This class of Flowerless Plants
ofi'ers very many points of interest to the
microscopist ; and indeed the use of magni-
fying-instruments is indispensable in their
examination for botanical purposes. The

Fig. 221.

Scolopendrimn Tulgare ; underside of frond.
Kat. size.

Ferns are characterized by the position of
their spore-cases or fruits (thecre, sporangia,
or capsules), which are collected into what

to the naked eye look like spots, streaks,
or patches of a brown colour (son) at the
back or lower surface of the leaves or fronds
(fig. 221), or at their margins, — these fer-
tile leaves either resembling the rest, or
being modified in a manner which more or
less disguises their natui'e, as in what are
miscalled 'flowering Ferns' {Osmunda (figs.
222 & 223), Botrychium, Sec).

The Ferns possess a stem which is more
or less developed in different cases : in our
native kinds it is either a slender, horizon-
tal, subterraneous rhizome or rootstock, or
a thick, short, erect one rising little above
the ground ; but in foreign kinds this erect

Fig. 222.

Fig. 223.

Osmunda regalis.
Fig. 222. Upper part of a fi-oud, l-6th nat. size.
Fig. 2-JS. A fertile pinnule bearing thecse •without
parench}nia. Magnified 10 diams.

stem attains the forms and dimensions of a
tree, growing up into a tall unbranched co-
lumnar stem, sometimes more than fifty feet
high. The anatomical structure of the
stem of the Ferns is peculiar and special,
depending on the character and arrange-
ment of the fibro-vascular bundles (see
Tissues, vegetable), which afford the
best examples of that form of elementary
tissue called the Scalaeifoem ducts. The
creeping rhizomes are often clothed more
or less thickly (as are also the leaf-stalks)
with brown membranous scales called Ra-
MENTA ; and these often aflbrd elegant mi-
croscopic objects, from the peculiar aiTange-
ments of the cells. The leaves are gene-
rally very greatly developed ; and the green
blade is of more" or less complex structure
in diflerent genera. In the Ilyme^iophyUa,

FER^^S.

[ 320 ]

FERNS.

Filmy Ferns, the leaf is ordinarily a mere
membrane of a single layer of cells, throug-h
which ramify scalarifrom ducts, to form the
veins — consequently there are no stomata ;
but in the other orders, in Pteris for ex-
ample, the leaf has an upper and lower epi-
dermis with stomata, with loose cellular
tissue {niesophyllum), between and through
which ramify the fibro-vascular veins : the
epidermal cells often have elegantly zig-
zagged or waving side-walls, which pro-
duce a pleasing appearance in the sections
of the structure obtained in slices shaved off
horizontally from the surface of the leaf.

The mode of ramification of the veins or
nerves of the leaves is important in system-
atic Fihcology, and may be observed for
such purposes by immersing the dried leaf-
lets in turpentine or oil, or mounting them
in Canada balsam. The collections of spo-
rangia or capsules on the back of the leaves
sometimes occur on all of these ; in other

Fig. 224.

Nephrodiiun.

Pinnule with indusiate sori.

Magniiied 10 diameters.

cases there are barren leaves and fertile
leaves, the latter of which are generally
somewhat modified in form, deprived of a
ce'lain portion of the green expanded struc-

ture, and reduced occasionally to a mere
ramification of veins or ribs supporting the
spt)rangia (fig. 22-!3).

The groups of sporangia are called so7-i ;
they ditl'er much in form and arrangement,
and are either naked (Polypodium) , or co-
vered by a special membranous structm-e,
more or less continuous with the epidermis
of the lower siu-face of the leaf, called an irv-
dusium or involucre (fig. 224) ; sometimes
this indusium is so constructed as to form a
kind of cup (figs. 127 & 151), which, again,
exhibits a great variety of modifications.
(See SoM and Indusium.)

The thecte or sporanc/ia are usually col-
lected in great numbers in the son ; and con-
sist of minute stalked sacs or cases, com-
posed of simple cellular membrane, the cells
of which are either all alike (Ophioglos-
sum), or a row of them running almost
round the sac are modified by the thick-
ening of their walls, so as to form an elastic
band (annulus), which causes the bursting
of the sac when ripe. In the Polypodiaceae
the annulus starts from the stalk of the
capside (fig. 225) ; in Hymowphyllum and

Fig. 225.

Polypodiiun verrucosum.
Stalked thecae with annuli. Magnified 25 diameters.

Fig. 226.

Fig. 227.

Curatopteris thalictroides.
Fig. 226. Thica. Magn. .=10 diams.
Fig. 227. Do. bursting. Do.

FERNS.

[ 321 J

FERNS.

Trichomanes it runs round in an oblique line
(like the ecliptic line on a frlobe) ; in Gloi-
cheiiia it is alst) oblique (tig. 231) ; and in
Scfiizcea and A^teimia (fig. 12, p. 41) &c.
it forms a kind of cap on the summit of the
case.

229.

Fifr. 230.

Ceratopteris thalicfroides.
Figs. 228-230. Spores. Magn. 150 diains.

Fig. 231.

Gleichenia."
A theca. Magnified 40 diams.

These membranous sporangia are filled
with spores having a double coat, like pol-
len-grains ; and, as in these, the outer coat
is ordinarily coloured, and either smoothish
or marlted with points, streaks, ridges, or
reticulations (figs. 228-230, 232-235). (See
Spores.)

Fig. 232.

Fig. 234.

Fig. 235.

Spores of Ferns.

Fig. 232. Aneimia asplenifolia.
Fig. 233. Polyijodium aiireum.
Fig. 234. Cystopteris fragilis.
Fig. 23.5. Pteris longifolia.

Magnitied 100 diameters.

The reproduction of the Ferns by tlieir
spores exhibits some very remarkable phe-
nomena. When the spores are sown, they
germinate after a time by a protrusion of
the inner coat as a delicate membranous
pouch (fig. 236), which elongates and be-
comes divided by septa into an articulated
cellular filament; some of the cells emit
slender tubular, not septate, filaments, form-
ing radical hairs; and while these remain
imcoloured, the larger cells from which they

Fig. 236.

Fig. 237.

Fig. 238.

Fiff. 239.

Grermination of Pteris longifolia. Magn. 100 diams.

arise acquire chlorophyll-gTanules. The
joiing 2}rot/ialliiim, as it is called, increases
in size by cell-division, and at length ac-
quires somewhat the form of a heart (figs.
2-36-239). Some of its cells produce, upon the
margin or the under sm-face, the trichoma-
tous structures called anther idia; which con-
sist of staUied cellular bodies, of simple but
peculiar structm-e, in the interior of which
are developed minute cellules containing
ciliated spiral filaments, the spermatozoids.
These are corkscrew-shaped, with 3 or 4

coils, and the front end finely ciliated.
On the bursting of tlie antheridial sac,
they escape, not only from this, but from
their own parent-cells, and swim about
actively in the water by the aid of their
vibratile cilia (PL 40. fig". 34).

The antheridia are often formed in large
numbers, and the prothallium goes on pro-
ducing them ns long as it exists; but at a
period somewhat later than that of the
earlier antheridia, there appear near the
middle, at the front of the under surface of

FERNS.

[ 322 ]

FIBRINE.

Fio-. 240.

the protliallium, other cellular bodies, of
more complex structure, which are the
archeijonia or ovule-like bodies. The arclie-
goiiiuui consists of a cellular papilla, com-
posed of a few colourless cells, with a caual
running down its centre (an intercellular
passage) leading to a cell {emhnjo-ceU) at
the b.jttom, contained in a cavity {Pinhri/o-
sac) in the substance of the prothalliuui.
The ciliated spiral filaments make their way
down this canal, like the pollen-tubes
through the micropyles of Phanerogamous
ovules ; and then the embryo-cell becomes
developed into an embryo, which soon
exhibits rudimentary leaves and rootlets,
bursts out from the cavity of the protlial-
lium, which decays away, and grows up
into the ordinary leaf-bearing
stem of the Ferns (fig. 240).
The prothallia bear a vari-
able number of archegonia,
but not nearly so many as of
authcridia ; and they exhibit,
in most fully-developed spe-
cimens, a number of effete
organs of both kinds, which
are readily distinguished by
the deep-brown colour as-
sumed by the membranes
bounding their cavities.

The characters of the prothallium of the
Ophior/lossaceci' differ somewhat from the or-
dinary forms : the prothallium is developed
in the soil, several inches below the surface,
and is of a whitish-yellow colour internally,
being destitute of chlorophyll and starch ;
its external surface is brown. The anthe-
ridia are chiefly produced upon the upper
side, the archegonia below, both immersed
in the substance of the prothallium. The
spermatozoids are described as being larger
than in Polypodiacete.

The Ferns produce also (jemmce on the
leaves of full-grown plants; and even the
prothallia are capable of vegetative mul-
tiplication ; f )r if their archegonia are all
abortive, they go on vegetating for a long
time, and produce new prothallia, by some
of their marginal cells budding out and re-
peating the original mode of growth of the
spore itself. These innovatioits usually bear
antheridia alone, and not archegonia.
The Ferns are divided into six orders.
Gleiciieniace^I':. Sori dorsal, of few
thecpe, naked ; theca) opening vertically by
a broad transverse complete annulus.

Poi.Yi'OT)iACE.i3. Sori dor.-al or mnrpi-

Pteris, seedlin"

nal,

subglobose ;

tliecse numerous, with or

without an indusium, usually stalked, more
or less completely surrounded by a vertical
annulus, and bursting transversely (except
in Hymjnophylleai).

OsMUNDACE^. Thecsetwo-valved, open-
ing across the apex, with a short horizontal
annulus; vernation circinate.

ScHiz^ACE.E. Thecfe two-valved, open-
ing down the side, crowned bv a complete
operculiform annulus ; vernation circinate.

MARATriACE.E. Thccps opening by a
lateral slit or a pore at the apex ; no annu-
lus, usually united into concrete masses
(synangia) ; vernation circinate.

Ophioglossace.e. — Tliecse deeply two-
valved, opening down the side nearlv to
the base ; no annulus ; vernation erect.

BiBL. Berkeley, Crypt. Bot. 507 ; Presl,
Pteridof/raph. IS-'jtj; I'ayen, Z?o^. Cryptoc/am.
1850; iMrichoitKniptoyam. Getrdc/ise, 1828;
Mohl, Martinson I'lunt. Cryptoy. Brasil. ;
Moore, Index Filicum & Handb. of Br. Ferns ;
Newman,i)r.i^ftrwA'; Henf rev, D^re/. of Ferns
from Spores, Linn. Tr a ns.xxi. 117, 18*53 ; He-
product, of Cryptoyajnia, Ann. N. II. 1852 ;
Ilofmeister, Entuickehiiiy, Sachs. Ges. 1857,
v. ; Reess, Jnltr, wiss. Bot. v. 1866 ; Stras-
burger, Bcfruchfunq, Ja/ir. unss. Bot. 1869,
vii. 390 ; Kny, Mmafsh. Berl. Aknd. 1869 ;
id., Jahr. wiss. Bot. A'ii. 1 ; Janczewsky, Bot.
Zeit. 1872,418; Sachs, Bot. 415; Hooker,
Syn. Filic. (fiys. of all yen. and description of
all species) ; Kny, Ann. N. II. 1870, v. 233 ;
Strasburger, ibid. 1870, v. 331 ; Smith, Hist.
Filic. 1875 ; "V^'aldner, Ferns of Germany,
1880 ; Blair, European Ferns, 1881.

FIBRINE. — Fibrine exhibits very nume-
rous fine fibres ; and is soluble in, or rendered
so transparent by acetic acid, as to be
invisible. Its chemical relation to the
other proteine-compovmds has not been
satisfactorily determined. A substance re-
sembling fibrine in many of its characters,
if not identical with it, occurs upon the
surfaces of inflamed membranes, &c. ; in
these cases it generally includes the other
elements of inflammation, and almost al-
ways a number of mimite granules of fat.

Fibrine is coloured by the test-liquids of
Millon and Pettenlcofer.

According to Schmidt's experiments,
fibrine does not pre-exist in blood, but is
formed by the chemical combination of
a fibrinogenons substance occurring in the
blood-plasma with a fibrino-plastic matter
contained in the blood-corpuscles, which
escapes from them ; more recently, Schmidt
considers the separation of fibrine to depend

FIBROIN E.

[ 323 ] FILAMENTOUS STRUCTURES.

upon the action of a ferment (see Froy,
HM. 1(5, and -M. Baker, IViys. !J8).

Till' tibrinons plasma of the lower animals
resemble?: tibrine in man^' re.-<pects, but does
not separate in tibres.

FIBiiOINE. — The principal cliemical
constituent of silk, cobwebs, and the horny
skeleton of sponges ; but the latter is now
considered to be composed of a new sub-
stance, spomiine. In the pure state, it is
white, insoluble in water, alcohol, ether,
acetic acid, and ammonia.

Bmr,. That of CHinrisTRY, animal.

FIBRO-PLASTIO TISSUE. See Tis-
sue, nnno-PLASTic.

FIBROUS and FIBRO-VASCULAR
BrXDUP]S. See Tissuks, vegktable.

FIBROUS STRUCTURES of Plants.
— This terra is somewhat equivocal, and
requires a little explanation here. In com-
mon laujiiiage all vegetable substances are
termed fibrous which can be separated into
more or le.-s line threads possessing a certain
degree of tenacity ; special examples are
furnished by those forming the materials
for textile fabrics. But the anatomical or
microscopical structures comprehended here
are exceedingly varied, including not only
liber-fibres, but spiral vessels, and even
hairs. Thus, Flax (PI. 28. fig. 2) is tlie
liber of Linum usHatissimum ; Hemp (PI.
28. fig. 6) of Cayinahis ; Jute (Pi. 28. fig-. 3)
of Corchorus capsuJaris kc. ; Puya (PI. 28.
fig. 26) of Bcehnieria Puya, and the material
of Chinese gi-ass cloth (PI. 2^. fig. 2o) of
Bahmcria nivea; Coir (PI. 28. fig. 4) the
liber-like fibre of the husk of the cocoa-nut;
Manilla hemp (PI. 28. fig. 7) of the fibro-
vascular bundles of Musn textilis ; New-
Zealaad flax of Phormmin tenax ; Espar-
to grass of Lijgeum esparto ; and Cotton
(PL 28. fig. 1) consists of the hairs covering
the seeds of species of Gossypium. These
and similar substances are also spoken of
under Liber, Hairs, and under theii' re-
spective heads.

In botanical language, the word fibre has
come into use in two very different senses.
First, any long cell attenuated to a point
at both ends, and with its walls thickened
with ligneous secondary deposits, is called a
Jihre by some authors. Thus the term woody
fbre is applied to the shorter cells of this
kind which make up the substance of most
solid woods; while the term liher-Jibve is
applied (with more justice) to the often
extremely elongated wood-tubes which form
the elements of the liber of Dicotyledons

and the woody part of the fibro-vasfular
bundles of the Monocotyledons. (See Tis-
sues, VEGETABLE.) The characters of
structures of this kind will be given under
Liber and Wood. Secondly, the term
Jihve is applied to the secondary deposits
upon the walls of cells, vessels, ducts, &c.,
which, instead of forming continuous pitted
layers, take the pattern of spiral or analogous
lines, and, by increasing in consistence, sub-
sequently form real fibres, often elastic and
unrollable, of firmer substance than the
cell-wall upon which the}^ Avere originally
deposited. The numerous modifications of
these^6ro2M clepodts upon the walls of cells
are spoken of under the heads of Spiral
Structures, Vessels, and Secondars

DEPOSITS.

It must not be omitted here that the walls
of many cells and liber-fibres, which appear
at first sight to be composed of homogeneous
laminpe, may often be made to exhibit spiral
streaks, by the use of reagents and macera-
tion ; indeed they present themselves during
the natural dissolution of the membranes
of some of the OsciUatoriacec'e (Aixactis,
ScHizosiPHON — PL 8. figs. 13, 15). Hence
some authors have recently recurred to the
old notion that all vegetable membranes are
formed of fibres cemented or blended toge-
ther. This is again strongly combated by
others, as regards the primary membrane of
cells. We enter more particularly into the
details under the article Spiral Struc-
tures fif Plants.

FI'CUS, Linn. (Figs). — A large genus
of Urticaceae (Dicotyledons), some of which
possess a remarkably thick epidermis and
curious pseudo-glandular structures con-
nected with it. Ficus elastica, one of the
plants j'ielding india-rubber, now commonly
grown in pots in rooms, is a good example.
The clavate bodies (PL 48. fig. '27) of Meyen,
developed in cavities in the leaf, beneath
the epidermis, contain crystalline deposits.
(See Glands and Raphides.)

FILAMENTOUS STRUCTURES op
Plants. — This name would be more appli-
cable than fhroiis strncfures to such sub-
stances as Cotton, which consists of elon-
gated hairs (PL 28. fig. 1), and indeed to all
elongated cellular filaments with thin and
collapsing walls. It would include aU long
vegetable hairs, like those forming the
coma on many seeds (Poplars, Asdepias,
Gossypium, Sec.) ; also those forming felty
coatings on the epidermis, as in many Com-
posita), &c. It is also applical)le to the

y2

FILAEIA.

[ 324 ]

FISSIDEXTE.E.

cells of most of the Coufervoid Algae, to
the mj'celium (flocci) of Fimgi, and to tiie
medidlaiy layer of the lichens. Many
other instances will suggest themselves to
the microscopist.

riLA'KIA, Mull.— A genus of Eutozoa,
of the order Nematoidea.

Char. Body filiform, very long, nearly
uniform ; head not distinct from the body ;
mouth romid or triangular, naked or with
papillae ; white, yellowish, or red, from 48
to 100 times as long as broad; oesophagus
short, tubular, narrower than the intestine ;
anus terminal, or nearly so ; spicula two,
of unequal size, more or less twisted ;
vulva situated very near the anterior extre-
mity.

Several species, many of which have been
imperfectly examined. They are most
commonly found in the abdominal cavity
and between the peritoneal folds of mam-
malia and birds, in the blood and the air-
cells of the latter, sometimes in the subcu-
taneous cellular tissue. Species are also
met with in reptiles, fishes, arid insects.

F. medinensis. The hair- or Guinea- worm.
Common in the intertropical regions of the
old world. Length G to 10" ; breadth 1-20
to 1-10". F. hronchtaUs occurs in the human
bronchi ; F. lachrymalis in the laolirvmal
gland ; F. ocuJi (papillosci) in the globe of
the eye, or beneath the conjunctiva; F.
imniifis in the heart of the dog; F. rliyti-
2)leurites in the cockroach, &c.

F. sanr/uinis is capillary, unifonn, with-
out papilke, the neck narrowed, the tail of
female simple, bluntly pointed, the vulva
close to the head, and the anus near the tip
of the tail ; length of adult 3i", of embr^'os
i5o-tV". It is found in the immature
form in human blood and urine, in chyluria
and endemic ha3maturia. The adult form
occurs in the subcutaneous connective tissue
of the scrotum, &c.

Two species occur in fresh water, under
the leaves of aquatic plants :

F. aquatilis. Fem. wliite, constricted
behind the spherical head ; tegument not
striated ; oesophagus capillary, very long,
sinuous ; tail gradually narrowed to a
curved point ; vulva anterior to tlie middle
of the bodv ; length 3-10 to 4-10"; breadth
1-250".

F. Idciisfn's. Fem. reddish-white, slightly
narrowed in front, but without a constric-
tion ; mouth very small, lateral, and oblique;
oeso])hagus filiform, very lojig, nodose at its

obliquely in a very small point ; tegument
not striated; vulva behind the middle;
length 1-2" ; breadth 1-140".

BiBL. Dujardin, Helmint/i. 42 ; Diesing,
Hebninfh. ii. 263 ; Kiichenmeister, Para-
siten, 304 ; Lewis, San. C'omin. 8th Hep.,
Calcutta, 1872; Leuckart, Paramt. 1879,
65 (tig.) ; Gruby and Delafond, Cnnpt. rend.
xlvi. 1217 ; Leidv and Welch, Mn. Mic. Jn.
1873, 157; Ann. N. II. 1878, ii. 199;
Cobbold, Parasites, 1879 (inost complete
literature).

FILELLU]\r, Hincks. — A genus of ma-
rine Hydroid Polvpi, fam. Lafoeidae,

1 species : F. serpens ; common on the
larger Sertulariidfe, especially ;S'. abietina.

IBrBL. Hincks, Brit. Zooph. p. 214.

FIR. See Pixus, Conifers, and
Wood.

FISCH'ERA, Schwnbe.— A genus of
Oscillatoriaceaj (Coufervoid Algae).

Char. Filaments irregularly branched,
composed of miiserial cells, with interstitial
subglobose cell ; surrounded by mucus,
forming an amorphous gelatinous stratum.

F. thermalis. On the walls of warm
springs (Rabenhorst, Fl. Air/, ii. 285).

FISSIDEN'TE.E.— A family of opercu-
late Acrocarpous (sometimes cladocarpous)
Mosses, of gregarious or cajspitose habit,
with simple or much-branched stems. The
leaves are amplexicaid (fig. 242), composed
of minute parenchymatous cells, closely are-

Fig. 241.

Fig. 242.

Fig. 243.

origm ;

tail conical, obtuse,

terminatmg

Fissidons bryoides.

Fig. 241. A plant of F. bryoides. Magn. 5 diams.
Fi^s. 212 &' 243. Leaves detached. More magnified
to show the appendage.

FISSIDEXS.

[ 325 ]

FLAX.

olatecl, often very papillose, produced at the
back and point into a lamina beyond tlie
leaf (tigs. 24o-24(J), whence three parts
ai'e distinguished in the latter : — 1, the
true liorizoutal blade ; 2, the dorsal lamina,
arising vertically from the back of the nerve;
3, the apical lamina, the preceding lamina
produced beyond the true horizontal blade

Fig. 244.

Fig. 247.

Fig. 245.

Tnonnnnnnnnr-ii u '

Fissidens bryoides.

Pigs. 244, 245, 246. Sections of 243, at various heights
from the base.
Fig. 247. Fragment of pei-istome. Magn. 100 diams.

of the leaf in a two-edged form, on each
side of the nerve. Capsule equal, rarely
annulate. British genus : Fissiiien.s.

FIS'SIDEXS, Hedw.— A genus of Fissi-
dentese. Character that of the family. In-
florescence moncecious or dioecious, terminal
on the main stem or on short secondary
branches. Montague has separated the
species w-ith an entire calyptra under the
generic name of ConomUrium.

F. Im/oides (tig. 241), not imcommon, is
a most elegant little moss.

BiBL. Wilson, Bnjol Brit. p. 301.

FISSURI'NA, Reuss. — A compressed
Layena, with slit-like aperture. It has the
same relation to Layena that Linr/ulina has
to Nodosaria.

BiBL. Reuss, Monogr. Lagen. in Sitz.
Ak. Wiss. Wim, xlvi. i". 18G3.

FISTULI'NA.— A genus of Polyporei
(Hymenomycetous Fungi), characterized by
the papillaj of the fleshy hymenophorum
being at length elongated and forming
distinct tubes, which call to mind those
of Solenia.

Fistulina heputica occurs not imfrequently
on old oaks, on which it sometimes attains

an enormous size, and when well dressed is
excellent for culinai'v purposes. The flesh
wlien cut resembles tliat of beet-root.

BiBL. IIuss. i. t. Go; Berk. Outl 257,
tab. 17. fig. 1 ; Cooke, Ilamlh. 292.

FLABELLI'NA, D'Orb.— One of the
K(>(hisariu<e. It is dimorphous — that is,
having two successive plans of growth : —
the first spiral, lOce that of CristeUaria ; the
later rectilinear, like that of Nodosaria, or
rather of Frondicidaria, which latter it
resembles in its chevron-shaped flattened
chambers. It differs from Frondicidaria in
an eccentricity, or tendency to coil, in the
earliest chambers, and thus connects the
Stichostegian with the Ilelicostogian groups.
It is to Frondictdaria as Vayimdina, Mar-
gimdina, and Plunidaria are to Nodosaria.
To many large flat C'risteUarife ( C. cassis)
semigeniculate chamber give a Flabelline
feature ; but pure FlubeUime are rare in the
recent state (Batsch figured one) and in
Tertiary strata. In the Chalk (Fl. n/yosa,
PL 23. fig. 38), Gault, Lias, and other
Secondary strata, Flahellince abound.

BiBL. D'Orbigny, For. Foss. Vicn. 92 ;
Morris, Brit. Foss. 35 ; Parker and Jones,
Ann. N. H. 3. xii. 136 ; Carpenter, Introd.
For. 100, 164.

FLAGELLA'TA. See Infusoria.

FLANNEL, NATURAL.— This term
has been applied to sheets or layers of a
harsh fibrous textvu'e, sometimes found

covering meadows,

rocks, &c. after an inun-

dation. It consists of the interwoven fila-
ments of Confervas, with adherent or en-
tangled Diatomacese, Infusoria, crystals of
carlDonate of lime, &c. To the naked eye
it closely resembles a piece of coarse or
loosely woven cloth. Similar layers are
frequently found upon the margins of pools
during the summer. As the water evapo-
rates, the Confervse and other organisms
remain supported upon the stems of rushes,
or blades of gi-ass, and, when dry, form the
yellowish, greenish, or gi'eyish layers of the
so-called natural flannel.

See Paper, meteoric.

FLAX. — The liber-fibres from the stems
of the Flax-plant, Linum usitcdissimum(jx&t.
ord. Linacese, Dicotyledons). Under the
microscope, the fibres (PI. 28. fig. 2) are
readily distinguished from those of Cotton
by the form and consistence, — being round
and attenuated to a point at each end, and
of a firm wood}' consistence, which prevents
them from collapsing, and having pits in the
wall. New-Zealand Flax is a totally differ-

FLEA.

[ 326 ]

FLORIDE^.

ent sulDgtance (Phoemium). See Fibrous
STnrCTUEES of Plants, and Liber,
FLEA. See Pulkx.
FLINT. — This is a subtranslucentTariety
of silica, forming nodules or bands in most
limestones. The organisms in flint are the
same as those met with in the chalk or other
limestone of which the flint forms part, as
a pseudomorphic replacement of the orig-inal
amorphous carbonate of lime by silex,
generally where decomposing organic matter
induced the conditions of change.

Much of the flint of the South of England
has been formed out of the calcareous mud,
crowded with small sponges, spicules, and
Foraminifera, which hold the same position
in the flint as they did in the cretaceous
ooze. Large sponges are often included,
with shells of Mollusks and Echinoderms,
scales of Fishes, and sporangia of Desmi-
diaceae, formerly recorded as distinct organ-
isms (XanthifJi(t).

The crystallized calcite of Echinoderms
and some shells is not replaced by silex in
limestones, but remains as cayities in ex-
posed flint-masses. Many yarieties of lime-
stone, yiz. polyzoan limestone in France,
freshwater limestone in France and Turkey,
orbitoidal limestone in Jamaica, oolitic
limestone at Poilland and elsewhere, are
conyerted into flint, hornstone, See. of fine
or coarse grain according to the constitution
of the original limestone.

Wallich has suggested that chalk-flints
are due to the nearly continuous proto-
plasmic layer among extensive sponge-
growths haying become silicitied.

In the examination of flint, thin sections
should be made by grinding and polishing ;
some kinds exhibit the organisms contained
in them best by reflected, others by trans-
mitted light. Some specimens, in which
they are abundant, will exhibit them well
in chips remoyed by a hammer.
See Agatk and Chalk.
BiBL. That of Agate and Chalk;
Ehrenb. Ann. N. H. 1838. ii. ]6i>; Turner,
Phil. Maq. 1833 ; Ansted,^w». i\^ II. 1844,
xiii. 248'; Jiowerbank, ihkl. 1847, xix. 240 ;
Charlesworlh, Geol.Jn. 1847, i. 20; Church,
Proc. Chcm. Soc. 18(32 ; id. Chem. Ketcs, y.
95, and Phil. Mciq. (4) xxiii. 95 ; Sutherland,
GeoJ. Man. ii. 220; Johnson, "i'7/«/," 1S71 ;
Jones, iVoe. Geol. Af.i>.oc.\\.A?j^; "\\'alli(h,
Qv. Jn. Geol. *Sbc., Feb. 1880; Sollas, .•l«?^
N. II.

FLOPTP'EyE or PTTOPOSPO'PE.E.—
An order of Alga). l\ed sea- weeds, some

of the common species of which must be
familiar to eyery one, as the delicate feathery
or leaf-like plants brought away by most
yisitors to the sea-coast ; and the red colour,
more or less permanent or fleeting, is a
pretty general characteristic of this order
— varying however to purple, brown, and
mixed tints of red, green, and yellow, and
dirty white ; the green colour of the chloro-
phyll being often obscured by a red pigment,
phyco-eri/fhrine. They chiefly grow in deeper
water than the other sea-weeds, and are met
with in finest and darkest colour in deep
tide-pools of sea-water, especially on the
side facing the north, where they are over-
hung by the larger dark-coloured Algae, and
thus shaded from the sun's rays. The greater
number do not grow more than six inches
high, few more than two feet. The simple.'t
foims are filaments composed of cylir.drical
cells attached end to end ; they next rise
to a gelatinous or cartilaginous expansion,
composed of such filamentous structures
adherent in layers, and forming a compact
frond of definite shape. These are said to
be oijUomentous structure. Others have the
frond composed of a number of polyg< ual
cells, evenly arranged, and with thick walls,
or, as some state, an intercellular substance
binding: them all together into a mass ; these
are technically said to be of ceUtdar structure.
Sometimes all the cells of the frond con-
tain colouring-matter, sometimes only those
of the surface, or of a shallow superficial
stratum.

The general external appearance of the
Red Sea-weeds is very varied. Sometimes
the fronds are like little leafless bushes ; at
others they form broad lamiutx? ; sometimes
the lower part is stalk-like, and the upper
parts spread into leaf-like kibes. In Ucles-
seria we have a close imitation of a regu-
larly formed leaf of one of the liigher plants.
The leaf-like forms are either simple, lobed,
or exquisitely pinnate or feathered ; and the
lihodosperms of warmer climates exhibit
most elegantly reticulated fronds. Some of
these plants deposit carbonate of lime in
their tissues in such quantity that they
become quite stony, so tliat, the vegetable
form alone remaining, they are commonly
mistaken for true corals (see Coral). By
placing these cornllincs and nulliporcs in
vinegar or diluti' h\droc]doric acid, the lime
is removed, and the cellular vegetable oiga-
nization may be recognized. The tropical
forms of the corallines are far moreyariid
and beautiful than our own.

FLORIDE.E.

[ 327 ]

FLORlDEiE.

I\ed or colourless albuiiiinous crj'stalloids
an' found in souie ot" the Floridt';u.

Three kinds of reproductive structures
occur iu these plants, viz. : — 1, tcfra^porcs ;
2, uporca ; 3, spcrmatozoids or anfhcrozoids.

The tt'tnispores or fefiru/onidia. These
structures are of similar organization

They consist of an

throughout the order

Fig. 248.

lihyiKUococcus eoronopifolius.

Section of the frond with tetraspores.

Magnified 200 diameters.

oblong or globular external cell or sac (pen-
spvre), at tirst filled with gramUar contents,

Fig. 249.

Ptilota plumosa.

Section of frond with tetraspores.

Magnified 200 diameters.

which contents subsequently separate into
four portions, called sporules, either by
three transverse fissures (fig. 248) ; by two
fissures at right angles, cutting them into
quarters like an orange ; or by tri-radiate
fissures which part them into the ' tetra-
hedral' group (fig. 249) so often found in
the division of spore- and pollen-cells : the
last two occur in the spherical tetraspores.
The tetraspores are rarely found collected in
any capsular structure ; but in the Corallines

Fig. 2r)0.

iiiiciaui'aiuMU(ia[ucLCci.o
comKituiecuauuuuuaaw

Hildenbrant san-

guinca.
Section of a concep-

{[\g. 141), and in some few foreign genera,
they are grouped iu hol-
low cases (co/iccpfnch's,
fig. 250). In many in-
stances, however, they are
found in pod-like bodies
(sfichidia, ri. 4. iig. l.-5?>),
either formed by meta-
morphosis of portions of
the lobes or lobules of the
frond (Pl(icaniiu>n), or
arising independently on
it. In others the tetra-
spores are naked (Calli-

tnammon), scattered over tacle containing tetra-

the sides or fixed at the tips spores,
of the branches. In the -^=»g"- 5° d.ams.
majority of cases, however, these bodies are
immersed in the substance of the lobes or
lobules, not evident externally except by
the darker colour of the frond at the point
where they are collected ; a lens is then
required for their detection : they here
appear to be formed either of the cells of
the surface or of others immediately sub-
jacent. Harvey, Thwaites, Priugsheim, and
others regard these bodies as (/emmiiles or
gonidia; Decaisne, J. Agardh, and other
Algologists regard them as true spores.
Pringsiieim states that in Cerammm they
grow up at once into a thallus.

The true spores are simpler structures
than the tetraspores, but mostly occupy a
more important position. They are never
scattered through the frond, but always
grouped in definite masses, generally enclosed
in a special capsule, conceptacle or cystocarp,
which is furnished with a closed tube or
trichoyync (PL 4. fig. 12 c). In fertilization,
the spermatozoids conjugate with the tricLo-
gyne (PL 4. fig. 12 a). Its basal cell then
subdivides, the new cells forming a sporife-
rous heap ; as in Nemalvon (and JBcdracho-
spermum). Or, the trichogyne-cell takes
no direct part in the formation of the spores,
which are produced after fertilization in
laterally arising new cells, as in the Cera-
miaceje &c. In Diidresnaya the elongated
trichogyne is spiral at the base. After its
fertilization, cells sprout from beneath it,
and elongate to form connecting tubes,
These pass over the ends of tlie fructiferous
branches, which aVe short with an enlarged
terminal cell, becoming soldered with them
at the points of contact, the contents being
mixed: each connecting tube conjugates
witli several of the fertile branches.

The simplest form of the spore-fruit con-

FLORIDE^,

[ 328 ]

FLOSCULARIA.

sist 9 of spherical masses of spores, attached to
the Avail of the frond, or imbedded in its
substance without a proper conceptacle, in
which latter case the cells surrounding the
mass of spores are devoid of colouring-
matter : such a fruit is called a favellidium,
and occurs in Jlalymenia ; and the same name
is ordinarily applied to fruits of similar struc-
ture not perfectly immersed, such as those of
Gigaiiina, Gelidium, Sec, where they form tu-
bercular swelhngs on the lobes. In some cases
the tubercles present a pore at the summit,
when mature, through which the spores find
exit. When such a fruit is wholly external,
as in Ceramimn and Callithmmiion, it is
called a favella. The coccidiutn, charac-
teristic of Delesseria (PL 4. tig. 5 c), i\7/o-
pliijllum, Sec, which is nearly related to this,
either occurs on lateral branches, or is ses-
sile on the face of the frond, and consists of
a hollow case with thick cellular walls, con-
taining a dense tuft of angular spores at-
tached to a central column. It is generally
imperforate, but occasionally exhibits a
pore through which the spores escape. The
a'ramidiuni is the most complete form
of the conceptacular fruit, and is an ovate
or lu'n-shaped case, furnished with an apical
pore, and containing a tuft of pear-shaped
spores arising from the base of the cavity.
The walls are usually thin and membranous,
and the hollow space considerable, as in
Polysiphonia, Lcmrencia, Dusya (PI. 4. fig.
9 c), &e.

From the account given by Pi-ingsheim,
of Cerammm, it would appear that these
(capsule-) spores first produce a kind of pro-
thallium, somewhat in the manner of the
higher Crj'ptogamia.

Peculiar bodies, forming external warts,
and composed entirely of vertical fibres,
but without spores, called nemcdhecia, are
sometimes confounded with the concepta-
cular fruit, and are probably immature forms
of it.

The spermcdozoids are found in peculiar
structures, to which the name of (odheridia
has been applied, from the supposed analogy
to the organs so called in the other Crypto-
gamous plants. The antheridia are pro-
duced pretty much in the same situations
as the other organs of fructification, and are
often developed on different individuals.
They are collections of very small colour-
less cells (PI. 4. fig. 126) ; sometimes col-
lected into a bunch, as in Gri/fif/tsia : some-
times enclosed in a transparent tube, as in
Pohjsiphonia ; clothing a kind of irregularly-

shaped flat plate, as in Laurencia ; or occu-
pying portions of the general surface of the
thallus. Each of the minute cells contains
a rounded motionless spermatozoid.

Synopsis of the Families.

Rhodomelace^. Frond cellular, areo-
lated or articulated. Ceramidia external.
Tetraspores in rows, immersed in rannili, or
contained in proper receptacles {stichidia).
_ LAirRENCiACE.E. Frond cellular, con-
tinuous. Ceramidia external. Tetraspores
scattered, immersed in the branches and
ramuli.

CoKALLiNACEJE. Frond calcareous or
crustaceous, rigid. Ceramidia external, cou-
taining the tetraspores.

Delesseiiiace.i:. Frond celliJar, con-
tinuous, areolated. Coccidin external. Tetra-
spores collected into definite clusters (sori).

RnoDYMENiACEiE. Frond cellular, con-
tinuous, the superficial cells minute. Coc-
cidia external. Tetrasporessc&iiere^ through
the frond, or forming luidefined, cloud-hke
patches.

Cryptonemiace^e. Frond fibroso-cellu-
lar, composed of articulated fibres connected
together by gelatine. FaveUidia immersed
in the frond or sub-external, Tetrasjjores
immersed in the frond.

Ceramiace^. Frond ^Wiovva, consisting
of an articulated filament, simple or coated
with a stratum of small cells. Favellce
naked berry-like " masses. Tetraspores ex-
ternal, or partially immersed.

PoRPHYEACE^. Frond plane and ex-
ceedingly thin, or tubular and fihform, of a
purplish colour, with oval spores in sori,
and tetraspores scattered over the frond.

BiBL. Harvey, Mar. Alga, 1849, & rhijc.
Brit. ; Kiitzing, Phycol. gen. ; Thuret, Ann.^
Sc. Nat. 3 ser. xvi. 5, 4 ser. iii. 5; Derbes
and Solier, ibid. 3 ser. xiv. 261, 4 s6i\ v.
209; Pringsheim, JBerl Ber. 1855; Ann.
Sc. Nat. 4 ser. iii. 363 ; Bot. Zeitung, xv.
784 ; Henfrey-Masters, Bot. 1878 ; IJornet
and Thuret, '^?iH. Sc. Nat. 1867, vii. 166 ;
Rosanoft", Coinpt. Bend. 1866 ; Cohn,
Sc/mltze's Archiv, iii. 24 ; Askenslry, Bot.
Zeit. 1867 (col. matter^ ; Solms-Laubach,
Bot. Zeit. 1867; Sachs, i?o/. 1874, 291.

FLOSCULA'RIA, Oken, Ehr.— A genus
of Rotatoria, of the family FIosculari;\3a.

Char. Attached ; eyes two, red ; carapace
single ; rotatory organ divided into more
than four lobes, with elongated cilia radia-
ting from their extremities.

floscui.ari.t:a.

[ 329 ]

FORAMINIFERA.

Eyes sometimes absent in the adult ani-
mals. Sheath or carapace irequently so
transparent as to be scarcely distinguish-
able. Rotatory organ with five or six lobes ;
the number, hcnvever, appears variable ; for
Ehrenberg states in one place that the lobes
are tive or six, in another that they are
always six. The so-called proboscis is pro-
bably only one of the lobes of the rotatory
orcrans ; freshwater.

>. ornuta, E. (PI. 43. fig. 32). Carapace
hyaline; rotatory lobes six (Ehr.), tive
(J3uj.), -svith long ciha, but no central pro-
boscis; length 1-108".

Lobes of"" rotatory organ thickened at the
ends.

F. pj'oboscidea, E. Carapace hyaline;
rotatory organ 6-lobed, with short cilia
surrounding a centrtd proboscis ; length,
when extended, 1-18". Teeth (tig. 33).

F. campanulata, Dob. Differs from F.
oniatd, Ehr., in having five lobes, and these
flattened ; length, when extended, 1-50".

F. cornuta", Dob. Rotatory organ 6-
lobed, one of the lobes with a narrowed,
not ciliated cornu attached, arising from its
outside : cilia long ; length, when extended,
1-40". '

Other species.

These exquisitely beautiful animals are
foimd adhering to aquatic plants, as Con-
ferva, CeratopJtyJlmn , &c.

BiBL. Ehr. Inf. 407; Duj. Inf. 609;
Dobie, Ann. N. H. 1849, iv. 233 ; Cubitt,
Mn. Mic. Jn. 1869, ii. 143 (PI.), and 1871,
vi. 83 (new spec.) ; Weisse, Sieh. S, KiJll.
Zeitsch. xiv. 107 (PI.) ; Hudson, Jn. Mic.
Soc. 1881, i. 4.

FLOSCULARLE'A.— A family of Rota-
toria.

C/uir. Furnished with a carapace or
sheath ; rotatory organ single, with a tiexu-
ous, lobed or divided margin.

The cilia are often long, and only vibrate
occasionally, mostly remaining rigidly ex-
tended.

Genera,

Eyes absent 1- Tubicolaria.

Eye single ^- Stephanoceros.

(t)\ -L J j single 3. Lhnnins.

Eyes j Rotatory J --'ooea-^ aggregate 4. Lacinulurla.
two} organ j 4-lobed o. .Uelicertn.

(.5- orb-lobed 6. Floscularia.]

The eyes in some of the genera {Stepha-
noceros and Floscularia) disappear in the
adult state ; so that they must be looked for
in the young, or even in the partly hatched
ova, in which they may often be distinctly
fceen.

BiBL. Ehrenberg, Infus. p. 398.
FLUKE. See Di stoma.
FLUS'TRA, Linn. (Sea-mat).— A genus
of Oheilostomatous Polyzoa, family Flus-
trida3.

Char. Polyzoarium plant-like, foliaceous,
flexible ; cells in contact, alternate, in seve-
ral rows, and on both sides of the polypi-
dom ; aperture transverse, semicircular or
lunate, valvular and subterminal. Marine.
F. foliacea. Cells narrow at the base,
rounded at the end, with scattered marginal
spines. Common; .about 4" high.

F. cliartacea. Cells oblong, slightly
broader in the middle ; lateral margins with
a single minute spine.
About 1" in height.

F. truncata. Cells linear-oblong, truncate
at the end, margins without spines : 4-5"
high.

F. carbasea= Carbasea papi/rea ; F. avi-
cularis= Bi((/ula Jlahellata ; F. Murrayana =
Bugida 31iirr. ; F. membranacea, coriacea,
and lineata = Membranipora m., c, and /.

BiBL. Johnston, Br. Zooph. 342 ; Reid,
Ann. N. H. 1845, xvi. 385; Busk, Brit,
litis. Catal. 47 ; Hincks, Pohjz. 114.

FLUS'TRAD^.— A family of Cheilo-
stomatous Polyzoa.

Distinguished by the expanded, foliaceous,
flexible and erect polyzoary, with its nu-
merous contiguous cells. Two genera,
Flustra. Cells on both sides.
Carbasea. Cells on one side only.
BiEL. Busk, Mar. Pohjz. (Br. Mus.) 46.
FLUSTREL'L.\, Gray.— A genus of
Ctenostomatous Polyzoa, of the order In-
fundibulata, and family Alcyonidiidaj.

Incrustiug, cells radiating or alternate,
the circumference with setaj ; oritice rect-
angular.

F. hispida. Common near low-water
mark upon Fitcus serratus. Polyzoary
brown, fleshy.

BiBL. Johnston, Br. Zooph. 363 ; Red-
fern, Qu. Mic. Jn. vi. 96; Hincks, Polyz,
504.

FLY. See MrscA.
FOLLICULA'RI A = i^;r/ff .
FO^TINA'LIS, L.— A genus of pleuro-
carpous Mosses.

F. antijn/retica, ^greater water-moss ; in
rivulets. F. sqnamafa. (Wilson, Bri/ol.
Brit. 422.)

FORAMINIF'ERA.— An order in the
Animal Kingdom, belonging to the Sub-
kingdom Protozoa, and class Rhizopoda.
Char. Gelatinous, structureless, usually

FORAMINIFERA.

[ .330 ]

FORAMIMFERA.

microscopic marine auimala, contained
■within calcareous sliclls, from orifices or
pores in which tine retractile processes are
emitted, by which locomotion and prehen-
sion are pertornied.

The shells are sometimes simple, con-
sisting of a sing-le cell or chamber (Unilo-
cular, Monothalanious, or Monostegian), as
in UnilocuUna, Qjrnuqnra, Ovulites, some
Trochaitintuue, La(/e)t(i, Orhidina, S'jnrillina;
but the cells are usually aggregated into a
compound shell (Multilocular or Polytha-
lamous). In some they are arranged end
to end in a straight row (Stichostegiau), as
in some Articidince , some Litiwlce, Nodosaria,
Frondicularia. In others the single row is
rolled into a spiral (Helicostegian, Naiiti-
loid, Turbinoid, or Fusuline), as in Penero-
2)lis, Lituola, CristeUana, Folystomilhi, Glo-
bigerina, the Rotalince, Nummtditcs, Fusu-
lina. Or the cells are arranged in two
alternate rows, spirally coiled (Eutomoste-
gian), as in T(dndiiui, Bidimina. Some-
times the cells forju two or three alternate
rows, but not spirally coiled (Eualloste-
gian), as in Vohjmoriddiia, ZJviyerina, Textu-
laria ; whilst in others the cells are arranged
around an (imaginary) axis, upon two or
more opposing laces (Agathistegian), as in
3idiola, C'lnhistomella. There are also dis-
coidal shells with alternately concentric cells
(Cyclostegian), as Orbitoldes and Cyclo-
clypeus. Many modifications, with di-
morphic and even trimorphic modes of
growth, also exist ; thus Textularia an-
tiectens (PI. 23. fig. 52) is helicostegian at
first, enallostegian subsequently, and sticho-
stegiau at last ; whilst Biyenerina and Cla-
vulina (PL 23. figs. 50 tfc 51) have only the
alternate and linear modes of growth ; and
Spirolina (PI. 23. fig. 12) is first spiral and
then linear. Between the chambers are
septa, consisting of either single or double
plates, pei'forated by one or more apertures
(whence the name Foramiuifera), the mar-
gins of which are sometimes more or less
prolonged to form tubes, as shown in figs.
31 & 41. This tube is sometimes turned
inwards (entosolenian). As the more re-
cently formed chambers are often larger
than the others, the shells ai'e often more
or less conical or pyramidal. The lines of
junction of the chambers, visible externally,
are called the septal lines ; these are some-
times sunk, sometimes raised into ridges.
Frequently the outer chambers extend
laterally beyond the inner, so as to conceal
them ; they are then said to be embracing.

In a few of the Foramiuifera the shells are
composed of a number of perfectly distinct
cells, each with a separate outer orifice
{Dactylopora, PI. 23. fig. 53).

The plan of g-rowth offers no solid ground
for the classification of these organisms ;
but the character of their shell-structure
serves better ; for there are two distinct
kinds of shell : — one white, opaque, and not
traversed with tubules ("porcellaneous" and
"imperforate"), such as the 3IilioIce ; the
other sub translucent and tubular ("vitre-
ous" or " hyaline,'' and " perforate "), such
as NodosariiKi, Bulituhia, and Nnmimdites.
Shells of each kind, however, are liable to
become " arenaceous," by particles of sand
or minute organisms being taken up in their
structure, as Quinqttclocuiiua, Liliiula, Tro-
chaminhut, Valvulina, Textularia, and Bidi-
mina.

The surface of the hyaline shells presents
a punctate appearance, arising from the
presence of very numerous foramina, which
are the outer orifices of tubides passing
through the walls of the shell. The ar-
rangement of these tubules and that of an-
other set traversing the walls and the septa,
as well as, in fact, the general structure of
the shell, may be illustrated by a descrip-
tion of the shell of Opercidina arahica (I'l.
24. fig. 23), in which they have been
carefully traced by Mr. Carter. Here the
outer surface, after the removal of a green-
ish epidermic layer, is seen to be covered
with large and small papilla; — the former
1-2150", the latter I-8G00" in diameter—
neither of which are present over the
septa or at the margin of the shell. Each
of the septa encloses within its walls two
calcareous tubes, spaces, or channels, one
on each side — the intraseptal channels
(tig. 20) ; these are about 1-1900" in dia-
meter, and in their course give ott" two sets
of lateral branches, terminating upon the
two surfaces of the septum in which they
run. The tubes communicate at each end
with a network of smaller ones ; one set of
which ramifies in the upper, the other in
the under wall or margin of each chamber ;
these are the marginal plexuses (fig. 24 h) ;
and the former terminate upon the outer
margin of the shell (// //). The inner wall
of the chambers is pierced by innumerable
tubules about 1-9000" in diameter, which
pass directly downwards from the small
papillic on the outer surface. In a vertical
section of the shell, in addition to these
minute tubes, seven, eight, or more parallel

FORAMIXIFERA.

[ 331 1

FORAMINIFEEA.

horizontal lines are seen (fig. 25 c) ; these
are the lines of C( intact of tlie hiyers com-
posing the shell, or the lines of growth. The
margin of the shell is traversed hy elongated
inosculating vessels, which cause the mar-
ginal portion to hreak up into calcar(>ou9
spicnla (iig. 24), 1-237" long and 1-900"
hroad. In a transverse section of the mar-
gin, more than 100 of these are seen, form-
ing a triangular bundle or cord (fig. 25 a),
the apex being directed towards the cham-
ber, the base outwards forming the free
rounded margin of the shell ; and parallel
to its side run the papillary tubes of the
chamber (tig. 25 b).

In addition to the common foramina and
the oritices of the marginal plexus, the
chambers, especially those which terminate
the series, are furnishetl with other larger
orifices opening ext:ernally; these are of
various forms find ditlerently situated ; some-
times they are round, numerous, and
comparatively small; at others they are
single and large, circular, semicircular, or
lunate, &c.

The nature of the Foraminifera has been
very difi'erently viewed. They were formerly
regarded as microscopic Cephalopoda, then
as Bryozoa (Polyzoa), and again as inter-
mediate between the Polypi and Echinoder-
mata. Dujaidin's view^, however, is now
fidopted, that their structure is very simple,
and that they are closely allied to the Arcel-
lina, the body being single and composed
of a simple sarcodic substance, without
the distinct separation of organs, the fili-
form processes (pseudopodia), which issue
from the various external apertures of the
shell being comparable with those of
Ainaha, Arcella, and other members of the
family.

Tlie chambers contain a soft translucent
colourless substance ; and often one or more
minute, round, granular bodies (sarco-
blasts) are present. These appear to have
been sometimes regarded as nuclei. If the
corpuscles described by Hertwig and Schidze
as nuclei are really such, the Foraminifera
may be ranked as high as the Amoebina.

The nature of the contents of the intra-
septal and marginal vessels is doubtful ;
Mr. Carter regards them as performing a
water-vessel function comparable to that
of the circulating system of the sponges
{Graiitia) ; whilst ^Villiamsonand Carpenter
consider them to be filled with the organic
substance (if the body.

The shells of Foraminifera are rarely

quite chitinous ; some have a chitinous base
with either a sandy or a calcareous coating.
Mostly they are altogetlu-r composed of
carbonate of lime, and therefore effervesce
with a dilute acid. By carefully acting
upon the recent organisms with muriatic
acid, in the proportion of a drop of the
strong acid to a watchglassful of water
containing them, the animal is left (PI. 23.
fig. 32), retaining the general foim of
the shell, which it has mouldi'd upon it-
self.

In the ''porcellaneous" group the shell-
matter covers each segment of sarcode tent-
wise, the edges of the new" chambers resting
on the outside of the older part of the shell.
In the "hyaline" group each segment is,in
many cases, fully enwrapped with shell,
except at the septal orifice, through which
the stolon connects the new and old seg-
ments. Besides this tubuliferous shell-layer,
many of the hyaline Foraminifera lay down
other coats, by the investing sarcode,
before new segments are set off; and
these supplementary layers not only form
ridges and tubercles, but also the " inter-
mediate skeleton," in which vessels or
canals, for the sarcode passing outwards,
are more or less prevalent, constituting the
" Canal-system."

Recent Foraminifera can be procured by
dredging, or sometimes from the sand of the
sea-shore. They often form white lines or
bands, between tide-marks. To separate
them, the sand should be washed in fresh
water, dried, and spread upon a piece of
black paper, or the black disk (Intbod,
p. xxvi), and examined as an opaque object ;
when the shells, easily distinguished by
their forms, may be picked out by means of
a mounted bristle.

Or the dried sand may be stirred up with
water and allowed to settle ; the sandy par-
ticles will then subside, and the shells, from
their cliambers being filled with air, may be
skimmed off the surface ; or they may be
poured off through muslin, with the dis-
turbed water, before all the sediment has
had time to settle.

In the fossil state, the Foraminifera
abound in Chalk, from which they may
be obtained in tJie manner directed under
Chalk ; in fact this substance constitutes
one of the best sources of them for exami-
nation. In other calcareous rocks or lime-
stones they are also extremely numerous.
Thus in the stones of which the buildings
in Paris are constructed, the shells of tlie

FOEAMTNIFERA.

[ 332 ]

FORAMINIFERA,

Miliolidfe are so abundant, that tliis city
may be said to be built of them.

The Nummulites or coin-stones which
form mountains in the Mediterranean and
North-Indian regions, and of which the
pyramids of Egypt are principally composed,
are Foraminifera (PI. 24. figs. 21, 22).

Many clays, such as those of the Lias, the
Oolitic and Cretaceous series, and London
Tertiaries, those of Prussia, Belgium, Ma-
laga, San Domingo, &c., and many shelly
sands of Tertiaiy age in Suffolk, Italy, Ger-
many, France, New Zealand, Australia, and
elsewhere, also yield Foraminifera by careful
washing.

See the articles Chalk and Rhizopoda.

Synojitical List of the Genera and Suhgenera
of Foraminifera.

(The subgenera are placed in parentheses.)

Division A. IMPERFORATA.

Subdivision 1. CIIITINAOEA.

Group I. Test chitinous, imperforate.

Fam. 1. Gromidae.

Groniia, Dujardin ; LieberkzieJmia, Cla-
parede ; Shepheardella, SiddaU.

Subdivision 2. CALCAREA (Porcel-
lanea).

Group II. Test calcareous, imperforate,
porcellaneous, and sometimes sandy ;
occasionally chitinous and sandy.

Fam. 2. Miliolidae.

a. MiLiOLixA. — Bath y siphon, G. O. Sars ;
Sqwimidina, Schultze; Nuhecularia, De-
france ; Miliola, Lamarck, Plate 23. fig. 1
( = Miliolina, Williamson); (Uniluci/lina,
d'Orb., PI. 23. fig. 2; Bilocnlina, d'Orb.,
PL 23. fig. 3 ; Spirolocuilna, d'Orb., PI. 23.
fig. 7 ; Trihcidina, d'Orb., PI. 23. fig. 4 ;
Quinqitelocidina, d'Orh., PI. 23. figs. 5, 6;
Crnciloculina, d'Orb. ) ; Cornuspira, Schultze,
PI. 23. fig. 13 {Ojjldhalmidium, Kiibler) ;
Ninnniuloculina, Steinmann ; Hauerina,
dOrb., PL 23. "a^.?)', Vertehralina, d'Orb.,
PL 23. fig. 9 (Articulina, d'Orb., PL 23. tig.
9); Fahularia, Defr.

b. Orbitolitina. — Peneropjis, de Mont-
fort, PL 23. fig. 11. (Bendrifina, d'Orb. ;
8pirolina, Lamarck, PL 23. fig. 12.) Orln'cu-
lina, Lam., PL 23. fig. 19 ; OrhitoUtes,
Lam., PL 23. fig. 17 ; Alveolina, d'Orb., PL
23. figs, ir,, TO.

c. ? Dactyloporina. — Ovulitcs, Lam. ;
Ilaploporella, Gihnhel ( = Dacfi/!ina, Zbor. ?),
PL 23. fig. 53; Dactylopurella, Giimb.
{=DactyInpora, Lamarck, in parte), PL 23.
fig. 54 ; ThyrsoporcUa,Gum\).\ Gyroporella,
Giimb. ; CylindreUa, Giimb. ; Uteria,
Michelin ; Acicularia, d'Ai'chiac.

Subdivision 3. ARENACEA.
Group III. Test calcareous and arenaceous.

Fam. 3. Astrorhizidse.

Psammosphcera, Schultze ; Swosphcm'a,
Brady; Saccammina, M. Sars; Pilulina,
Carpenter ; Storthosphcera, Schidze ; I'ech-
nitella, Norman ; Pelosina, Brady ; Asche-
monella, Br. ; Astrorhiza, Sandahl ; Dendro-
phrya, Str. Wright ; Rhabdammina, M.
Sars ; JacideUa, Br. ; Hyperammina, Br. ;
Psanimatodcndron, Norman (MS.); Saye-
nella, Br. ; Botellina, Carpenter ; Marsi-
pella, Norman ; JLdiphysema, Bowerbank ;
Polyphrayma, Reuss.

Fam. 4. Lituolidse.

("These comprise sandy isomorphs of the
simpler types of the Ilyalina, such as La-
gena, Nodosaria, Glubigerina, Botalia, iVb-
nionina, &c.)

Litnola, Lam., PL 23. fig. 23 {Peophax,
de Montfort; Haplophraymium, Reuss; Ha-
phistiche, Rss. ; Placopxiliua, d'Orb. ; Bdcl-
loidina, Carter) ; ' Trochammina, Parker &
Jones, PL 23. fig. \4:(Hormosina,V>i-AA\ ; Am-
modiscus, Rss. ; Webbina, d'Orb., PL 23. fig.
21) ; Nodosinella, Br. ; Inwlutina, Ter-
quem ; Endothyra, Phillips ; Stacheia, Br. ;
Thurammina, Br.; Hippocrepina , Parker;
Cyclammina, Br.

Fam. 5. Parkeridse.

Parheria, Carpenter ; Loftusia, Brady.

Division B. PERFORATA (Vitrea vel
Hyalina),

Group IV. Tests of many of the larger
forms arenaceous, with more or less
of a calcareous perforate basis ; smaUer
forms hyahne and perforate.

Fam. 6. Textularidae.

a. Textularina. — Te.rtnlaria, Defrance,
PL 23, figs. 47, 52 (Vulvulina, d'Orb., PL
23. fig. 49; Biyenerina, d'Orb., PL 23.
fig. 50; yenilina, Gumbel; Pavonina

FORAMINIFEEA.

[ 333 ]

FORAMINIFERA.

d'Orb. ; Sju'roplecfa, Ehrenberg ; Cnncolina,
d'Orb.) ; Venwuilina, d'Orb. {Gaudryiita,
d'Orb., PI. 23. fig. 48 ; HetcrostomeUa, K^s. ;
ChniMilhlina. d'Orb. ; Trifa.rin, Rss.) ; Val-
vuli'iia, d'Orb., PI. '23. tig. 20 {aariihna,
d'Orb., PI. 23. fig. 51).

b. BuLiMiNiXA. — Bidiminct, d'Orb., PI.
23. fig. 46 ( Viri/idina, d'Orb. ; Bolivina,
d'Orb. ; L'iffinii(i,'l\ kJ .; liobcrti)ia,dVvh. ;
Pkurostoinella, Reuss).

e. Cassidulinina. — Cassidulinn, d'Orb.,
PI. 23. fig. 4.J ; Ehrenhergina, Reuss.

Group V. Test calcareoiis, finely iDerforate.
Fam. 7. Cliilostomellidee.
ChilosfomeUn, Reuss; Allomorphina,
Reuss ; EUipsoidina, Seguenza.

Fam. 8. Lagenidse.

a. Lagenina. — La(/ena, Walker and
Jacob, PI. 23. figs. 22, 24-27 {Entosolenia,
Ehr., PI. 23. fig. 23 ; Fissurina, Reuss) ;
Bamulma, Jones. Nodosarina : — Nodosaria,
Lam., PI. 23. fig. 28 {GlanduUna, d'Orb.;
Benfalina, d'Orb., PL 23. fig. 33; Liiiffu-
lina, d'Orb.) ; Orfhocerina, d'Orb., =Rhah-
do(/oniinn, Rss., PL 23. fig. 36 ; Frondicu-
laria, Defr., PL 23. fig. 39 {Amphimov-
2Jhina, Neugeb.) ; Vaginulina, d'Orb., PL 23.
fio-. 35 (Bimidim, d'Orb.); Marginnlina,
d^Orb., PL 23. tigs. 30-32; CristeUaria,
Lam., PL 23. figs. 34, 37 {Plamdaria,
Defr.) ; FlabeUma, d'Orb., PL 23. fig. 38.

b. Polymorphinina. — Pohjmorphina,
d'Orb., PL 23. figs. 40-43 (Dimorphina,
d'Orb.) ; Uvigerina, d'Orb., PL 23. fig. 44
{Sagriyia, d'Orb.).

Group YI. Test calcareous, generally witli
coarse perforations; without canal-
system.

Fam. 9. Globigerinidae.

Globigerina, d'Orb., PL 24. figs. 2, 3 {Or-
bidina, d'Orb., PL 24. fig. 1); Pidknia,
Parker and Jones ; Spharoidma, d'Orb.
(PL 24. fig. 4) ; Ccmdeina, d'Orb.

Group VIL Test calcareous, coarsely per-
forate ; some with double chamber-
walls and interseptal canals.

Fam. 10. Rotalidde.

Spirillina, Ehrenb. (PL 24. fig. 5} ; Pa-
tellina, Williamson (PL 24. fig. 8) ; Discor-
bina, P. & J. (PL 24. fig. 7); PlanorbuUna,
d'Orb., PL 24. figs. 6, 10, 12 (TruncatuUna,

d'Orb., PL 24. fig. 9; yl?)/)»!«//»//,d'Orb.) ; Pu-
pe.rtia, Wallich ; Carpentaria, Gray; Polg-
trema, Risso; Tinopiorus, Carpenter (= Gyp-
sina, Carter) ; Cyndxdopora, von Hagenow
(PL 24. fig. 17) ; Tkalamopora, Rss. ; Pd-
vinidina, P. & J. ( PL 24. figs. 11 , 16) ; Rot alia,
Lamarck (PL 24. tigs. 13, 14); Calcarina,
d'Orb.

Group VI II. Test calcareous, very finely
tubulated ; all the higher forms with a
system of interseptal canals.

Fam. 11. Nummulitidae.

a. Polystomellina. — Nonionina, d'Orb.
(PL 24. fig. 18) ; Poh/stomella, Lam. (PL 23.
fig. 55, PL 24. figs. i9, 20).

b. NuMMULiTiNA. — Archcsdiscus, Brady ;
Amphistegina, d'Orb. (PL 24. fig. 28) ; Fu-
sulina, Fischer (PL 24. fig. 15) ; Eozoon,
Dawson ; Cydoclypem, Carpenter ; Hete-
rostegina, d'Orb. ; Operculina, d'Orb. (PI.
24. figs. 23-26) ; Nummulites, Lam., PL 24.
figs. 21, 22 (Assilina, d'Orb.).

Unplaced groups : —

Group IX. Testamojbiformia, Carter.

Lobose forms.

a. Test calcareous. — Ilolocladia and Cys-
teodictyina, Carter.

b. Test chitinous. — Cerastestina, Carter.

Group X. Syringosphaeridae, Duncan. Test
calcareous, with radiating groups of
tubules.
Syringosplireria and StoUczharia, Duncan,

Group XL Receptaculitidae, Giimbel. Test
calcareous, consisting of an inner and
an outer floor of plates, connected by
the tubes of an anastomosing canal-
system.
Receptaculites, Defr. ; Ischadites, Konig ;

Tetragonis, Eichwald; Sphceronites, Hisin-

ger ; Sp)hcerospongia, Salter.

BiBL. D'Orbigny,Z>«c^. Sc. NatAS2Q,x\\.;
Mem. Soc. Geol. France, iv. ; Diet. d'Hist.
Nat. 1845, V. ; Foram. foss. Vien. 1846 ;
Ehrenb. Mikrog. 1854; lA. Abh. Ah. Berlin,
1838, 1839, 1841, 1847, &c. ; Weaver, Ann.
N. H. 1841, vii. 296, 374 ; Dujardin, Ann.
Sc. Nat. 1835, iv. & v. ; Clark, Ann. N. II.
1849, iii. 388, 1850, v. 161; Williamson,
Tr. Micr. Soc. ii., and Recent Foraminif.
{Ray Soc.) ; Carpenter, Tr. Geol. Soc. 1849 ;
Microscope; Phil. Tr. 1856, 59, 60, 69;

FORD A.

[ 334 ]

TEA GIL ARIA.

Introd, Foram. ; Carter, Ann. N. H. 1852,
X., 18')3, xi., 1854, xiv., &c. ; Schultze,
Organism. Polyf.hal. ; Mii/ler's Archiv, 185L!
(Q. J. Micr. Soc. v. 220) ; Wiec/mann^s
Archiv, 18G0 {Ann. N. II. ser. 3, vi'i. 30G) ;
Parker, Jones, and Brady, Ann. N. II. 2.
xix. ; 3. iii., iv., vi., viii., xi., xii., xv., xvi. ;
4. iv., vi., viii., ix., x. ; Q. J. Geol. 8oc. xvi.
292, 452 ; xxviii. 103 ; Phil. Trans. 1865 ;
Tr. Linn. Soc. 1864 and 1870; Monoijr.
Cray For. ( Pal. Soc. ) 18()6 ; lieusa, Verst.
liohm. Kreid. 1845-46 ; Haiding. Ahhandl.
iv. ; Denksch. Akad. Wien, i., vii., xxiii.,
XXV. ; Sitz. Ak. Wien, pas.sim ; Zsitscli. dent,
geol. Ges. iii., vii., &c. ; Giimbel, Abliandl.
bayr. Ak. x. tfcc. ; also the memoirs of Sol-
daui, Ro.uer, Vou Ilageuow, Pliilippi,
Reuss, Czjzek, Alth, Bornemanu, Egyer,
Neogeboren, Karrer, &c.

Since 1875 the following have added to
the bibliography of the subject : —

A. M. Norman, J. D. Siddall, J. II. Carter,
W. J. Sollas, .1. F. Blake, E. Vanden Broeck,
Joseph Wright, H. B. Brady, A. W. Waters,
Ph. de la Harpe, W. K. Parker, T. R. Jones,
G. Stache, F. Karrer, C. W. Giimbel, J. W.
Dawson, (J. Schwager, M. von llantkeu,
G. Steinmann, G. C. Wallich,P, M. Dnncan,
G. Terrigi, C. Miibius, J. Seguenza, &c.

FOR'DA, Ilevdeu. See Aphid.!-:, p. 63.

FORFIC'ULA, Linn. F. auricidaris is
the common earwig.

FORMIC ACID, or acid of ants.— This
acid occurs in ants, especially the red ant,
Furmicarnfa; in the stinging hairs of some
insects, as of the procession - caterpillar
{Bomhy.v processionea); and in the pi-isonous
secretion of the stings of insects ; perhaps
also in the stinging organs of the AcalephtB
and Polypes. In the higher animals it is a
frequent product of the oxidation of organic
substances, and is also foimd in the juice of
flesh, in the lu'ine, in vomited liquids, and
in the blood ; also in the stinging hairs of
the nettle &c.

FOSSIL INFUSORIA. — The fossil
valves of the Diatomaceoe were formerly so
called. See Diatomace.e.

FOSSIL WOOD.— This occurs in very
dift'erent conditions : — as, for example, con-
verted into lignite, and the modifications
of coal ; or with the vegetable substance
almost entirely removed .and replaced by
sile.x;, preserving all the organic forms of
the tissues. The mode of examining and
mounting Coal, kc, is given under that
article. Silicilied woods wliich have been
completely infiltrated and solidified require

to be cut into thin sections and polished by
the lapidary ; the friable kinds, where the
infiltration has merely filled the cavities of
the cells and vessels, may be split with a
knife and mounted in balsam. Examples
are given in PI. 25. figs. 29-33. PI. 48.
fig. 32, exhibits concretions of silica imi-
tating structure. The stems of Palms and
Dicotyledonous trees are met with com-
pletely converted into siliceous blocks, sei--
tions of which exhibit all the miuutiaj of
the structure.

FOSSOMBRO'NIA, Raddi.— A genus of
PellietB (Hepaticie), nearly allied in the
character of its vegetative structure to the
Jungermaunieee, having large, squarish,
irregularly waved leaves. The stout stems
are procumbent, and set with purple radi-
cles all alou'j: the underside. The fruit-
stalk arises from the underside of the stem,
and turns back; the periclnete is very large;
and the capsule bursts irregularly into four
slender crose valves, F.pusilla is the Jun-
germannia pusilla of the British Flora ;
found chiefly on clay banks.

BiBL. Hook. Brit. Junyerm. pi. 69, Brit.
Flur. ii.pt. 2. 117; Endlicher, Gen. Plant.
suppl. i. no. 472-7.

FOVIL'L.A. — The name appUed to the
liquid granular matter tilling the pollen-
cell and pas.-ing into the pollen-tube of
Flowering Plants. The minute granules,
which are of various but altogether indefi-
nite sizes, exhibit an active quivering mo-
tion— the molecular motion, as it is called
— which is displayed in the same way by
all finely-divided solid substances, living or
dead, and is apparently dependent on purely
physical causes. They appear to consist of
starch-grains, minute globules of oil, and
granules of protoplasm probably composed
of proteine compounds. These granules are
exceedingly transparent in many kinds of
pollen when fresh,' from their refractiiig-
powx'r being nearly equal to that of tlie
fluid surrounding them. They may be made
visible bv adding water.

FRAGILA'RIA, Lyngb.— A genus of
Diatomaceae (Cohort Fragilarieic).

Char, Frustules (in front view) linear,
symmetrical, united into straiglit ov twisted
flat. filaments ; valv«s lanceolate, oblong or
linear.

Difl'ers from Diatoma in the filaments not
becoming separated into zigzag chains.
Transverse stria? only visible under oblique
or "slopped'" illumination.

Kiitzing enumerates sixteen species, of

FREDERICELLA.

[ 335 ]

FRONUICULAKIA.

which ten are dduhtful. Eahenhorst fid-
luits !J spt>cii'8, with nunierous varieties.

F. capucina, K. (F.rhabdusoma, E., PI. 16.
fig. 33). Friistules linear iu front view ;
valves narrowly and acutely lanceolate ;
breadth of tilament 1-700", Freshwater.
Common in pools, &c.

3. Valves attenuate towards the obtuse
ends.

F. rirescens, Ealfs {F. pectinalis, Ehr.).
Frustules in front view linear, rectangular
or cuneate ; valves obtuse at tlie contra'ted
and produced ends. Freshwater. Endo-
chronie green.

(3. Valves cohering by the angles only.
F. striafidn. ^'alves linear, narrowed
toward.^ the very obtuse ends. Marine.

BiBL. Kutzing, BacUl. 45; id. Sp. Ak/.
14; Ralfs, Ann. X. H. 1843, xii. 106;
Smith, Brit. Diat. ii. 21 ; Rabenhorst, Flor.
Alq. i. 118.

FREDERICEL'LA, Gervais.— A genus
of Polyzoa, of the order llippocrepia, and
family I'lumatellidas.

Char. Polypidom fixed, coriaceous, tubu-
lar, branched ; polypes protruding from the
ends of the branches ; tentacular disk nearly
circular ; tentacles about twenty-four, ar-
ranged on the margin of the disk in a single
series, and invested at their origin by a
membrane. Freshwater.

F. sultana. Polyj^e-cells erect, cylindrical.
Height of zoary about 2" ; tufted, shrub-
by ; stem dichotomously branched. Eggs
bean-shaped, smooth.

BiBL. AUman, Freshw. Polyzoa {Bai/
Soc), 110; Johnston, Br. Zooph. 40-5.

FREI'A, CI. & L. — A genus of Infusoria,
of the family Bursarina.

Char. Those of Steyitar, with the buccal
spire borne by an anterior membranous bi-
lobed expansion.
3 species : marine.
F. elegans (PI. 62. fig. 1.).
BiBL. Clap, and Lachm. Infits. 217; St.
Wright, Qu. Mic. Jn. 1862, 217.
FREY'A. See Frkia.
FROG. — The common frog (Bana tempo-
raria) affords a means of studying several
interesting points of structure. Thus, by
genth' scraping the back of the roof of the
mouth with the handle of a scalpel, ciliated
epithelium (PI. 49. fig. 13) may be obtained,
and the ciliary movement studied. The
circulation in the web of the foot, and the
phenomena of inflammation may be ob-
served, by enclosing a frog in a wet bag,
leaving one leg projecting. The bag con-

taining the frog may then be placed upon a
plate of wood, witli a circular aperUue at
one end, over which the foot is to be ex-
tended by tying the toes with silk or cotton
threads to little tacks or nails driven into
the wooden plate. Metal " frog-plates "
are sold for the purpose. Sections of the
kidney of the frog, made with a Valentin's
knife, will show the ciliated epitlielium of
the necks of the urinary tubules. The
circulation of the blood in the lungs and
the mesentery may be examined ; but tlie
animal should be rendered insensible by
chloroform before the experiment.

The ova of the frog (frogs' spawn) have
formed the subject of some of our most
interesting experiments on impregnation
and development. The larva) (tadpoles)
exhibit well the circulation in the gills,
tail, and more transparent parts, and afford
easily obtained matei-ials for the study of
the development of the tissues. The chorda
dorsalis is well seen in a young tadpole.
The frog and tadpole, however, are inferior
in most respects to the Triton and its larvae
for exhibiting these phenomena.

The injected organs of the frog afford
most interesting and beautiful preparations,
especially the lungs, kidneys, skin, tongue,
and Aveb of the foot. The injection should
be thrown in at the heart, and the slightest
possible force used. The simplest method
of killing a frog without injury, is to
immerse and retain it in warm water.

The muscles of the frog often contain
a nematoid parasite (^Myonjhtes Weiss-
mamii).

FRONDICULA'RIA, Defr.— This pseu-
do-genus comprises flat stichostegian Nodo-
sarina, which have geniculate or chevron
chambers. They are the extremelj^ com-
pressed and dilated forms of the group,
having tlie quasi-genus Lhujrdina to connect
them with the cylindrical Nodusarke. In
Fro7idtctdaria the shell is equilateral ; nar-
row-oblong, rhomboidal, or ovate ; greatly
compressed; chambers iu a straight row,
depressed, each forming two sides of a tri-
angle, with the angle sometimes prolonged ;
septal lines often raised as ridges ; inter-
mediate spaces sometimes striate ; first
chamber oval; aperture roimd, on the upper
angle.

Recent in the Atlantic. Fossil in the
Tertiaries of Italy, Spain, and West Indies ;
and abundant in the Chalk, Gault,Lias, and
other fossil clays. Fr. spafhulata (PI. 23.
fig. 39) shows the early portion of a speci-

FRONTOXIA.

[ 336 ]

FUCACE^.

men from the Chalk, closely allied to the
typical Fr. complanata, Defr.

BiBL. D'Orbigny, For. Foss. 57 ; Wil-
liamson, Fee. For. 23 ; Moms, Br. Foss. 35 ;
Reuss, Boh in. Kreid. ; Carpenter, Introd.
For. 160, 164.

FRONTO'MA, Ehr.— A genus of Infu-
soria, of the family Bursarina (CI. & L.).

Char. Resembles Ophri/of/leiia, except in
the absence of the watch-glass organ.

Most of the species of Dujardin's genus
Fanophrys belong here.

F. leucos (Bursan'a 1.,'Ehr.). Parenchyma
armed with trichocysts ; buccal fossa oval,
pointed behind j a single contractile vesicle.
Freshwater.

BiBL. Ehrenberg, Inf. 329 ; Clap, and
Lachm. Fifus. 259.

FRULLA'NIA, Raddi.— A genus of Jun-
germanniefe (Hepaticfe), containing three
British species, the Jimgermmmia Hutchin-
si'ce, dihffafa, and Tamarisci of Hooker's
British Flora. F. dilatata is very common,
creeping on the bark of trees, its dark brown
dry foliage appearing like minute spreading

Fig. 251.

Fmllania Tamarisci.

Portion of a stem, with branches bearing the pericheetes
from which the sporanges emerge.

Magn. 5 diams.

blotches ; the almost sessile capsides are
somewhat inconspicuous, but are distin-
guished by their whitish colour. The valves
of the capsule and the elaters aftbrd beauti-
ful microscopic objects, illustrative of the
spiral structures in cells. F. Tamarisd
(tig. 251) has longer and more regidarly pin-
nate stems, forming large lax tufts on the
ground and hnv buslies, cliieHy in Subalpine
countries.

BiBL. Ylook. Brit. JwKjcrman. pis. 1, 5, 6;

Brit. Flora, ii. pt. 1. 128 : Endlicher, Gen.
Plant. Suppl. i. No. 472-10.

FRUSTU'LIA, Ag.— A genus of Diato-
macese.

Char. Fnistules naviculoid, free or irre-
gularly scattered through an amorphous
gelatinous mass ; valves elliptic-lanceolate,
without central and terminal nodules ; lon-
gitudinal line interrupted in the middle.
Freshwater.

F. salina, Ehr. Frustules in front view
very narrowly linear, rounded at the ends ;
valves suddenly acute at the ends ; trans-
verse stria} evident; gelatinous envelope
continuous ; length of frustules 1-2200 to
1-864". Found in a saline spring.

This organism is of particular interest,
as having formed the subject of Schmidt's
ultimate analysis, in which he determined
the presence of cellulose. (Diatojiace^^e,
p. 249.)

F. membranacea^ nobis (PL 50. fig. 6).
Frustules in front view linear, very slightly
narrowed towards the ends ; valves lanceo-
late, constricted near the obtuse ends;
length of frustules 1-1250".

Found abundantly forming a thin stratum
or film upon the sides of a glass jar con-
taining water-plants.

F. saxonica, Rab. (PI. 19. fig. 17). Frus-
tules in front view linear, rounded at the
ends ; valves elliptical, somewhat acute.

Forms du-ty olive-brown, gelatinous, tre-
mulous masses, contained in small pits in
rocks.

This is sometimes used as a test-object.
It is regarded by Dallinger and others as
the same as Navicida rhoinboides and crassi-
nervis.

Rabenhorst describes 5 species ; one
fossil.

BiBL. Ehreub. Lifiis. 232 ; Kiitzing,
Bacill. 109; id. Sp.Alg. 96; Rabenhorst,
Fl.Alq. i. 227; llidda, M. 31. Jn. 1876,
XV. 122 ; Stodder, ibid. 253 ; DalHnger, ibid.
1877, xvii. 1, 173.

FUCA'CE^:.— A family of Fucoideje.
Olive-coloured inarticulate sea-weeds, whose
reproductive organs are borne in staUced sacs
upon the walls of spherical cavities excavated
in the substance of the frond. Fructijication,
sporanyes or spore-sacs and anfheridia. The
spores of Fucus divide into two, four, or
eight within the sac ; those of the other
genera remain undivided. The antheiidia
are filled with spermatozoids or anthero-
zoids, which in Fucus have been seen to
fertilize the spores. See Ftjcus.

FUCOIDE.E.

[ 337 ]

FUCOIDE^.

British Genera.

* Air-vessels stalked.

Sargassum. Branches bearing ribbed
leaves ; air-vessels simple.

Ilalidn/s. Frond linear, pinnate, leafless ;
air-vesseis divided into several cells by
transverse partitions.

** Air-vessels immersed in the substance of
the frond or absent.

Cystoseira. Root scutate. Frond much
branched, bushy. Eeceptacles cellular.

Pycnophycus. Boot branching. Frond
cylindrical. Beceptacles cellular.

Fucks. Boot scutate. Frond dichotomous.
Beceptacles filled with mucus, traversed by
jointed threads.

Himanthalia. i2oo< scutate. Frond cup-
shaped. Beceptacles (frond-lilie) very long,
strap-shaped, dichotomouslv branched.

FUCOI DE.'E, or MELA^'OSPORE^.
— An order of Algae, deri^-ing their ordinary
name from the Funis or Wrack, one of the
most common genera of the family. They
present many remarkable points of difference
from the red"^ sea-weeds in their higher forms,
while the loAvest forms approach the simpler
genera of that order and the higher forms of
the Confervoideae. The Fucoids are exclu-
sively marine, and are at once distinguished
by their olive or dark-brown colour; and
although some of the larger kinds grow in
deep water, the majority are met with on
rocks between high- and low- water mark,
where they are exposed to the atmosphere
at each efflux of the sea : those which are
occasionally drawn up from deep water prove
that this exposiu-e is necessary for healthy
growth, by their weak structure and the
absence of fi'uctification. Some of them
are also provided with air-bladders, which
maintain them floating or erect and with at
least their upper lobes little beneath the
surface of the water. These air-bladders
are very well seen in our common Bladder-
wrack {Fucus vesiculosus, fig. 252) ; and still
more so in the celebrated Gulf-weed {Sar-
gassum bacciferu7n),yvheTe the stalked berry-
like bladders are the most striking feature
of the plant.

All the larger kinds grow on rocks, to
which they are attached by a root-like
structure, of somewhat conical form, cleav-
ing, like the 'sucker' with which school-boys
lift stones, to the rock ; in many this cone
is solid, and composed of tough cellular
tissue ; iu others, especially the Laminaria-

cese, it is composed of a number of stout,
supeijacent, branched cords, growing out of
the frond one above another, and attaching
themselves to the rock, like the roots of a
Tree-fern or a Palm. Some (Pycnophycus)
spring from a creeping stem-hke portion,
spreading in a netted mass over the rocks, —
while many of the smaller are parasitical
or, more properly, epiphytic, growing on the
fronds of the larger kinds, to which they
attach themselves by minute 'sucker '-like
disks. Some appear to be true parasites
{Elachistece and Myrionematd). Several are
of minute size, but very few strictly micro-
scopic. Almost all present three regions,
resembling respectively the root, stem, and
leaf or leaves of the higher plants, although
they are not ordinarily reparded as the
morphological analogues of them. In a few-
cases the frond is a shapeless mass or crust,
lying close to the surface of the rocka.
None become calcified like the Corallines.

The fructijication of these plants is still in
a somewhat obscure condition as regards the
order in general; for great apparent divei'si-
ties occur in the physiological phenomena
presented by what at first appear like iden-
tical structures. We have here, as in the
2^Zor/f7e(?,thi'ee distinct forms of reproductive
structure, known respectively as: — 1, zoo-
sjjores ; 2, sjxjres ; and 3, spermatozoids.

1. The zoospores are the reproductive bo-
dies most frequently met with ; and in the
lower forms the arrangements are not very
different from those in the filamentous Con-
fervoids. In Ectocarpus, where the frond
is composed of jointed cellular filaments,
the cells at the ends of the branches, or
other articulations, become enlarged and
filled with gi'anular matter which is ulti-
mately converted into zoospores. These en-
larged cells are called by Thuret sporanyes,
and are commonly described as spores in
algological works ; but they burst and dis-
charge the numerous microscopic zoosjjores,
which are pear-shaped, with a clear, beak-
like, narrow end, of olive colour, and have
two cilia, not arising from the beak, but
from a reddish point on the coloured por-
tion ; one cUium is longer than the other,
and directed forwards ; the other is short,
and trails behind like a kind of rudder.
Their movements are very active ; and they
seek the light. When they germinate, they
become immovable and spherical, acquire
a membranous coat, and emit a tubular pro-
longation, which soon becomes divided by
cross septa, and is developed into a new

FUCOIDE^,

[ 338 ]

FUCOIDE.^.

fi'ond. In some cases the sporanges are
multilocular {t}-ichospo)-anffes) , consistmg of
very slender, and usually rather short, j ointed
filaments, in each joint (cell) of which a
single zoospore is produced. These occur in
considerable number, occupying the same
place as the unilocular kind, which they
sometimes accompany ; and the two forms
appear to pass one "into the other. The
zoospores are perfectly similar, except that
those produced singly in the filaments are
not so large as those developed in large
numbers in the large, ovate, unilocular
sporanges.

The two forms of sporange producing
zoospores have been found in the Myrione-
mapege,OhordariaceEe, Sporochnacese, Punc-
tariaceae, and Dictyosiphonacepe ; in Chorda
lomentaria only the multilocular, and in the
other Laminariacese only the unilocular,
have been seen at present.

The Cutleriacese present the remarkable
phenomenon of the occurrence of sporanges
containing zoospores together with anthe-
ridia analogous to those of the Fucace^.

(See CUTLERIA.)

Those Fucoidese in which the repro-
duction is effected by zoospores only, form
Thuret's group of Phseosporese.

2. The spores occur in the Dictyotaceje
and the Fucacece, as large granular bodies
of ovate form, enclosed in a sporange or
oogonium, and clothed besides by a gela-
tinous coat called the epispore ; these large
spores are always devoid of power of motion.
In some cases they are simple reproductive
spores ; in others they subdivide, after es-
caping from the perispore, into two, four, or
eight sporules, each capable of germination.
(See Fucus, and figs. 253, 256.) In the
Dictyotacefe these spores are collected into
definite groups {sori) on the surface of the
frond. In the Fucaceae the spores are
fovnid in spherical cavities immersed in the
substance of the frond, sometimes occurring
in all parts, sometimes collected in special
regions. These cavities communicate with
the external surface by pores, and are usually
perceptible from the swollen sliiny appear-
ance where they open. Where no general
receptacles exist, the little spherical cham-
bers are excavated in the frond ; where
these do occur, as in Fucus, the spherical
chambers are attached to the inside of their
walls, one beneath each external pore.
Tliese chambers, called by some scaphidia,
by others concepfacJes, contain spores or
antheridia, or both. The spores occur in

sacs consisting of a cell (perispore^ springing
from the wall of the chamber. (See
Fucus.)

3. Spermatozoids have been met with, as
well as zoospores, in the Cutleriacese. The
spermatozoids or antherozoids exactly resem-
ble those of Halidrys and rycnoplujcas,
described below.

In Dictyota the spermatozoids occur on
separate plants, in antheridia grouped in
sori like the spore-fruit.
■ In the Fucacefe the spermatozoids or
antherozoids occur with the spores above
described. In Fucus canalicidatus {Pelvetia,
Dene, and Thuret) and F. plntycarpus (Thu-
ret) the antheridia are found, in company
with the spores, in the conceptacles ; in the
other species of Fucus the two kinds of
organs are never met with together in the
same conceptacle ; in Himanthcdia lorea
they are on distinct plants, in Halidrys
silicpiosa intermingled, and in Pycnophycus
tuherculatus in the same chamber but not
mixed. The antheridia of these plants
consist of transparent ovoid sacs, inserted
in great number on the branched hairs
(para7icmata) (fig. 254) clothing the inside
of the fruit-chambers or scaphidia. In some
genera they have a double coat, in others
only one ; when two exist, the inner is
expelled as a sac on the rupture of the an-
theridium ; when only one exists, the sper-
matozoids are expelled individually and
freely from the single coat, which always
remains attached upon its support. The
spermatozoids or antherozoids found in
these sacs are little hyaline globules, each
enclosing a granide of grey colour in Fucus
canalicidatus, red-orange in all other species
of Fuctis and other genera. They bear two
locomotive cilia, verj' slender, and of unequal
length. The form of the corpuscles and the
arrangement of the cilia difl^er in difterent
genera. In all the species of Fucus the
spermatozoids are of the shape of little
bottles, the neck of which, always foremost
in the movement, bears the shortest cilium ;
the longer arises from the coloured granule,
and trails behind. In Halidrys, Pycnophycus,
and Cystoseira, the corpuscle is oval or
spherical in one dimension, and compressed,
sometimes a little convex, in the other;
both the cilia are inserted on the red granule,
and during the locomotion the corpuscle
turns upon its own axis, with the longer
cilium in advance, vibrating with rapidity,
while tlie shorter is motionless. In Himan-
thcdia the antheridia have a double coat; the

FUCOIDE.E.

[ 339 ]

FUCUS.

form of the antlierozoids is not clearly made
out. The antherozoids of the Fucacefe have
been shown by Thuret, their discoverer, to
be analogous to the spermatozoids of the
higher Cryptogamia, and to perform a ferti-
lizing function — not to reproduce the plant
like the zoospores of the other families ;
and the multiplication appears to be effected
solely by the large olive-coloured spores.
(SeeFucACEiE.)

Spwpsis of the Families.
FuCACK^.. Frond leathery or mem-
branous, cellular. Fructification : spores and
antheridia contained together or separately
in spherical cavities imbedded in the frond.
DiCTYOTACE.^. Frond cellular, flat,
compact. Fructification : spores, antheridia
(and tetraspores?) arranged in definite spots
or lines (sori) on the surface.

CuTLERiACEiE. Froud cellular, com-
pact, ribless. FrnctiJjcatio7i : dot-like scat-
tered collections of sporanges divided into
eio-ht compartments ; and antheridia con-
sistino- of chambered filaments in groups of
curved jointed hairs.

EcTOCAHPACE^. Frond filiform, jointed.
Fructification: unilocidar sporanges, ovate
sacs developed at the ends or intermediate
ioints of the filaments; and multi/ocidar
sporanges, consisting of minute jointed
filaments found in similar situations. An-
theridia Avith spermatozoids have been
foimd in Sphacelaria.

LAMiNAEiACEiE. Frond leathery or gela-
tinous, cellular. Fructification : unilocnlar
sporanges in indefinite cloud-like patches,
or covering the whole surface of the frond ;
or nndtilocular sporanges clothing the whole
surface of the frond like an epidermis.

DiCTYOSiPHONACE^. Frond cylindrical,
branched, of filamentous structure. Fruc-
tification : ovoid sporanges imbedded length-
ways in the substance of the frond, opening
by a pore on the surface.

PrxCTARiACE^B. Frond cylindrical or
flat, unbranched, cellular. Fructification:
ovate sporanges in groups on the surface,
intermixed with clavate filaments (jpara-

physes).

SpoROCHNACEiE. Jy-dMfZ leathciy or mem-
branous, cellular, branched. Fructification ;
uniloadar or multilncular sporanges attached
to external jointed filaments, free or collect-
ed in knob-iike masses.

Choedaeiace^. Frond cartilaginous or
gelatinous, composed of horizontal and ver-
tical jointed filaments interlaced. Fructifi-

cation : nnilocular sporanges springing from
the base of the vertical filaments forming
the epidermis of the frond; and mtdtilocrdar
sporanges developed later from the filaments
surrounding the former.

MvRiONEMACEiE. Frotid tuber-shaped,
crustaceous, or spreading as a crust, of fila-
mentous strncture. Fructification : nnilocular
and multilocular sporanges attached to the
superficial filaments, and concealed among
them.

BiBL. See that of the Families.

FU'CUS, Linn. — A genus of Fucaceee
(Fucoid Algae), including some of the com-
monest and most abundant of our olive-
coloured sea-weeds, growing upon rocks
and stones between tide-marks, their large
fronds waving in the water at high tide,
and lying matted together over the rocks
when the tide is out; continually cast
ashore in quantities after rough weather.
F. vesiculosus, the common bladder-icrack, is
familiar to every one who has visited a sea-
coast. Decaisne and Thuret divide the
genus into three: Pelvetia{F.canalicidattis),
Ozothallia (F. nodosus), and Fiicus proper,
including F. serratus, vesiculosus, and cera-
noides.

In F. nodosus and F. Machaii the recep-
tacles are lateral and stallied ; but in all the
rest they are terminal and continuous with
the frond (fig. 252), forming oval thickened

Fiff. 252.

End of a branch of F. vesiculosus, bearing two terminal

receptacles.

Half the nat. size.

clubs, on which, by the naked eye, may be
distinguished a number of spots or pores.
These are the orifices of the conceptacles,
which are globular cases immersed in the
substance of the receptacle, and communi-
cating with the outer surface by a pore (fig.
263). The central portion of the receptacle

z2

FUCUS.

[ 340 ]

FUCUS.

is filled up Tvatli a delicate network of jointed
filaments surrounded by a gelatinous sul>
etance, this medullary structure forming a
bond of imion between the numerous cou-
ceptacles. The internal wall of the con-
ceptacles is lined with a dense mass of de-
licate jointed filaments (fig. 253) standing
vertically (jMraphyses), among which ap-
pear the stalked sjwre-sacs, alone in the
dioecious and monoecious forms, mixed with

Fig. 253.

Section of a concfiitaLlu ui' i . i.uialiculatus, containing
sporanges, antheridia, and paraphyses.

Magnilied 40 diameters.

antheridia in the hermaphrodite. The an-
theridia occur alone in similar conceptacles
in the monoecious and dioecious forms. F.
canaUculatiis is hermaphrodite (like Pycno-
phyctts tuhercidatus, which, however, has
antheridia only at the upper part of the
conceptacle, near the pore, spore-sacs at the
lower part) ; in F. serratus, ceranoides, vesi-
ctdosus, and twdosxs the male and female
conceptacles occur usually on distinct plants;
but both kinds sometimes occur on F. nodo-
sus. The male and female individuals of
the dioecious species may often be distin-
guished, when mature, by the yellowish
colour the antheridia give to the recep-
tacles; and if these are exposed for a short
time to the air, the antheridia are expelled
in masses through the pores of the con-
ceptacles, and form little orange-coloured
papillae. The female plants under similar
circumstances exhibit olive-coloured papillae
at the mouths of the pores, consisting of
masses of spores.

The sj7oranges or spore-stacs consist of
ovate sacs, stalked, on the walls of the con-
ceptacle (fig. 253) ; they have a double
membrane — an outer, the sporatu/e or j)eri-
spore, and an inner, the epispore : these are
undistinguishable until the spores escape ;
but then the epispore becomes evident as an
inner sac. The epispore encloses at first a
mass of olive-coloured cell-contents ; in F.
canalicidattts {Pelvetia) this divides into two

spores, in F. nodosus (Ozothallia) into four,
and in F. serratus, vesicidvsus, and the other
Fuel proper, into eight, by segmentation.
When matm^e, the sporange bursts at the
apex ; the epispore enclosing the spores is
expelled, and makes its way towards the
pore of the conceptacle, and falls into the
water, where it undergoes the following
modifications. Taking F. vesiculostis as an
example, the expelled epispore encloses
eight spores, forming what Thuret calls an
octospore. This swells ; and the spores be-
come rounded, separating from each other ;
and the upper part of the epispore begins to
dissolve. The spores become removed from
the lower part of the epispore (marked by
the impression of the stalk of the sporange) ;
and it then becomes evident that they are
enclosed in a third membrane, which is at-
tached to the episjiure in the centre of its
base, so that as the spores emerge from the
dissolving summit of the epispore the in-
ternal membrane becomes stretched upward,
until it finally bursts and sets the spores free.
These changes of the octospore are generally
passed through in about an hour, sometimes
much more rapidly.

The antheridia consist of minute ovate
sacs, attached in great numbers to hair-liko
filaments growing from the internal surface
of the conceptacle (fig. 254). When young,

Fig. 254.

Fig. 255.

Fig. 2.54. A branched cell of F. nodosus, bearing a per-
fect and an imperfect antheridium. Magn. 200 dianis.

Fig. 2.55. Sao of an antheridium of F. serratus, nearly
empty. Magn. 400 diams.

they are filled with colourless granular
matter ; but subsequently this becomes con-
densed into little corpuscles (spermatozaids
or antherozoids), forming a greyish mass
dotted with orange points. The sac is
double ; and the internal one is expelled
from the outer like the epispore from the
sporange, and fuids its way out from the
pore of the conceptacle. The spermatozoids
which fill up the central part begin to move
actively ; and the sac soon bursts at one or
both ends to discharge them. The sperma-
tozoids (fig. 255) are excessively minute,
transparent bodies, scarcely 1-5000" long,
enclosing a granule of an orange-colour in

FUCUS.

[ 341 ]

FUNARIACE^.

most spores, but frroyish in F. cnnaliculafus.
The speriuatozoids have two cilia, of un-
equal length, one directed forwards, the
other backwards; the form of the sperma-
to/oids and the direction of the cilia vary
in different species, — the one directed for-
ward usually moving with great rapidity,
and producing locomotion, while the other
trails behind like a rudder.

The most interesting and important point
connected with the genus Fucus is the
process of fecundation.

When a drop of sea-water containing
active spermatozoids, is added to a slide
upon which the free spores above described
have been previously placed, the whole
operation of the fertilization may be traced
under the microscope. The spermatozoids
attach themselves in great numbers to the
spores, and by the motion of the cilia com-
mimicate to tliem a I'otatory movement,
often very rapid. The held of the micro-
scope becomes covered with these large
brownish spheres bristling with spennato-
zdids, and rolling in all directions among
the crowd of those still unattached. After
about half an hour, the movement of the
spores ceases ; the spermatozoids move for
some time longer. In a few minutes after
the contact of the spermatozoids, such fer-
tilized spores will be found coated with a
membrane, the presence of which is readily
made out by placing the spore in syrup,
which causes the granular contents to con-
tract and shrink away from the envelope,
which, moreover, may be coloured blue by
sulphuric acid and iodine. The spore next
begins to enlarge and grow by cell-division,
one end becoming elongated into a trans-
parent filament like a radicle (fig. 256) ;
several more of these are afterwards formed

Fig. 256.

Spores of F. serratuB in various stages of germination.
Magnified 100 diameters.

as the upper part grows ; and they become
organs of attachmpnt by which the young
frond is fixed to a stone or other support.

The above description corresponds in all
essentials to the process as it occurs in the
other species. The spores of F. vesicuJosus
have been fertilized with spermatozoids of
F. serratus by Thuret ; but no other expe-
riments of hybridation were siiccessfid.

One or two other points deserve notice.
The orange spot of the spermatozoids is co-
loured blue by sulphuric acid (like Chloro-
phyll). Sugar and sulphuric acid colour
the spermatozoids red (Proteine), The
membrane of the sporange {perispore) is
coloured blue by sulphuric acid and iodine
(Cellulose) ; but this is not the case with
the epispore nor the internal membrane,
even after treatment with caustic potash.
In F. canaliculatus, however, there is a la-
minated coat immediately surrounding the
spores, which when placed in sea-water
separate, while the coat swells and forms a
kind of gelatinous envelope, which appears
as if covered with cilia; these pseudo-cilia
seem to be analogovis to the similar appear-
ances in the gelatinous sheath of Desmi-
DiACEJE and other Confeevoids.

The months from December to March are
the most favourable for observing the above
phenomena. No covering glass must be
used on the slide, unless prevented by a thin
glass support from pressing on the spores
and deforming them, A power of 150 to
200 diameters suffices for most of the ob-
servations,— for the spermatozoids and the
actual fecundation, a power of 300. Sea-
water must always be used. The germina-
tion of the spores maybe observed by placing
them on glass slides moistened with sea-
water, and keeping them under a bell-glass
standing in a dish containing sand moistened
with sea-water,

BiBL. Harvey, Mar. Alg. 18, pi. 1 D ;
Phyc. Brit. pis. 47, 52, 158, 214 ; Greville,
Alg. Brit. pi. 181 ; Decaisne and Thuret,
Ann. Sc. Nat. ,S ser. iii, 5 ; Thuret, ibid.
xvi. 6, 4 ser. ii, 197, vii. 34 ; Sachs, Bot.
284 ; Bower, Jn. 3Iic. Soc. 1880,

FUNA'RIA, Schreb.— A genus of Funa-
riacefe (Acrocarpous Mosses), the common
species of which (F. hygrometrica') is well
known on account of the hygroscopic cha-
racter of its fruit-stalk, which twists in
drying, and untwists again when wetted.
It exhibits stomata on the neck of the
capsule (fig. 262).

BiBL. Vs'\\&on,Bryol.Br.2QS', Berkeley,
Handb. 176.

FUNARIACE.E.— A family of Funa-
rioidese (Acrocarpous Mosses) of loosely-

FUNARIACE^.

[ 342 ]

FUNARIACEiE.

tufted or gregarious habit, growing on the
ground ; the stem loosely leaved, very sim-
ple. Inflorescence monoecious; antheridial
flowers disk-shaped, mostly terminal on a
special branch. Antheridia small, oval.
Archegones small, narrowly apiculate. Pa-
raphyses filiform at base, club-shaped and
articulate at the apex. Peristome, if pre-
sent, cartilaginous, red, streaked, with soli-
tary, oblique, trabeculate teeth.

British Genera.

Funaria. Capsule asymmeti'ically arched
(fig. 257); orifice oblique, very small; stalk
much curved, elongated, very hygroscopic
and twisting. Calyptra ventricose-dimi-
diate, rounded at the base, obtuse, shorter
than the capsule, or larger and truncate at
the base (fig. 258). Peristome double, erect ;
outer of sixteen, oblique, broadly lanceolate-
subulate, trabeculate teeth, with appendices
near the point (fig. 259), chained together
at the apex by a reticular disk ; the inner
as many as the outer, opposite and adnate at
the base, lanceolate, granular, with a longi-

Fig. 257.

Fig. 258.

F. hibernica.

Fig. 257. A ripe capsule with its twisted seta.

Fig. 208. An immature capsule, covered by its calyptra.

Magnified 25 diameters.

tudinal line. Cells of the operculum circi-
nately reticulate at the apex.

Pyramidium. Calyptra squarely pyra-
midal, apiculate, entire at the base, far ex-
ceeding the capsule, totally covering it, in-
flated and persistent, bursting at the middle
of the side, longer. Capsule symmetrical.

F. hibernica.

Teeth of the peristome, with appendices.

Magnified 150 diameters.

erect, pyi-iform, without a peristome. Oper-
culum regularhj areolate.

Physcoinitrium. Cah'ptra mitre-shaped,
split at the base into several lacinia3, entire
below, much shorter than the capsule, with
a long apiculus. Capsule symmetrical,
straight, pyriform, without a peristome.
Operculum regularly areolate.

Entosthodon, Calyptra bladder-like, di-

midiate, with a long

Ym. 260.

apiculus, entire, roimd-
ed or truncate, readily
splitting. Capsule sym-
metrical, pear-shaped,
straight, or declined on
an arched stalk, with
or without a peristome.
Peristome, if present,
horizontal, erect when
dry, simple ; internal
wanting or scarcely
perceptible ; composed
of very short lacinias.
Teeth lanceolate, ivith-
out appendar/es, simple

or twin, flat outside, „ ,^^ ..,.

T ,' .... ' Capsule, maen. 2odjiams.

trabeculate within,

mostly oblique at the summit, connivent
but not connate. Operculum regularly
areolate.

A7nhIyodon. Calyptra hood-like, narrow,
very fugacious, lougish, very slender, com-
posed at the apex of very small, thickened,
square cells. Capsule asymmetrical, pear-
shaped, straight, with a peristome and an
annulus. Peristome double : external —
teeth sixteen, short, lanceolate, obtuse, erect,
trabeculate with a slender longitudinal line ;
//(^<'r««/— teeth equal in number, lanceolate,
subulate, fissile longitudinally in the middle,

Physcomitrium
pyriforme.

FCNARIOIDE^.

[ 343 ]

FUNGI.

smooth, mucli exceeding the exterual in
leugth, yellowish, placed on a shortl}^-
grooved "membrane. Operculum regularly
areolate.

FUNARIOIDE^E. — A suborder of
operculated Acrocarpous (terminal-fruited)
Mosses, with broadly-oval spathulate leaves,
furnished with a lax cyhndrical nerve, com-
posed entirely of large parenchymatous
cells, lax and parallelogrammic at the base,
lax, hexagonal, or polygonal towards the
apex, often very densely filled with chloro-
phyll-granuleSj'more or less pellucid. Cap-
sule pyriform,apophysate, the neck {coUtim)
mostly bearing stomata on its epidermis
(fig. 262).

Fig. 261.

Fig. 262.

r. hvgrometrica.

Fig. 261. Portion of the annulus. Magn. 100 diams.
Fig. 262. Epidermis of the coUum, witti stomata.
Magn. 100 diams.

This suborder is divided into two fa-
milies :

FuN.\EiACE^. Stem very simple ; ter-
restrial.

Splachnace.^. Stem very much
branched ; mostly occurring upon the dung
of animals.

FUXGI. — A class of Cellular Flowerless
Plants, growing in or upon damp (vege-
table) mould, in or upon the wood and the
herbaceous parts of li-ving or dead plants,
upon living or decaying animal substances,
in solutions of organic matters, &c. A few
occui' on bare stones or other inorganic sub-
stances, as a species of Cyphella and some
Myxomycetes; but this is quite exceptional.
A very large portion of the plants belonging
to this strange class are microscopic bodies,
only to be made out clearly by means of a
very high magnifying power. As in the
rest of the Thallophytes, moreover, the re-
productive bodies are simple and exceed-
ingly minute in the larger forms of Fungi ;
consequently dissection under the micro-
scope is requisite when it is desired to ob-
tain a satisfactory insight into their natui'al
history.

The Fungi do not appear to be capable of
assimilating inorganic food, and are distin-

guished from healthy specimens of almost
all other plants by the total absence of the
colour depending on the presence of chlo-
rophyll or its red modifications, and of
starch ; for it is scarcely to be doubted that
the various colourless filamentous structures
(Leptomitese, &c.) occurring in infusions,
chemical solutions and the like, are Fungi,
and not Algse as some have supposed. They
are allied by certain forms with the Algae
and with the Lichens ; but they are distin-
guished from all outwardly similar forms of
the first by the spore-bearing fruits always
being elevated into the air, when mature,
although the thallus or mycelium may be
aquatic. The higher forms of Fungi can
scarcely be confounded with the higher
Algaj. ' The separation from the Lichens is
more difficult ; indeed some authors have
come to the conclusion that the Lichens
must be reduced to forms of Fungi. Yet
the presence of green gonidial cells in the
thallus will generally sufliciently distinguish
the Lichens. We shall here follow the old
plan ; and the distinction ordinarily laid
down is, that the Lichens are enth'ely aerial
mcrMSiim^ plants, while the Fungi have their
vegetative structure immersed in the me-
dium in which they grow. Some of the
epiphyllous lichens, however, originate be-
neath the cuticle.

The structm-es of all Fungi exhibit a weU-
defined separation into two parts, namely: — •
1, a mycelium (thallus), or vegetative struc-
ture, consisting of a mass of exceedingly
delicate, jointed and branched, colourless,
interlacing filaments, forming a kind of
cottony or felty mass when growdng in the
earth, in vegetable structm-es, &c., or cloudy
flockswhen growing in decomposing liqmds.
In some cases, as in certain Sphcerice, the
threads are woven into a close mass, or, as
in Phallus, into filiform cords ; while in the
Myxomycetes the threads become obsolete
or are replaced by a jelly-like substance re-
sembling sarcode. 2, of the reproductive
structure or fruit, which, unlike the myce-
lium, ditiers extremely in appearance in the
various tribes.

The mycelium may be well examined in
the "spawn" used for planting mushroom-
beds ; this cottony substance consists of the
mycelium of that plant. The formation and
growth of the mycelium of the microscopic
species, such as moulds, mildews, &c., may
be traced under the microscope by scattering
some of the dust-hke fructifications (as the
blue powder of common paste-mould) upon

FUNGI.

[ 344 ]

FUNGI.

slips of glass, and keeping them in a warm-
ish place under a bell-glass over water, for
several days. The filaments will be seen
spreading from the spores in all directions,
and often advancing to the formation of the
fructification.

The. fructification of the simplest Fungi is
nothing more than a modification of one or
more cells at the end of a filament which
rises up from the general body of the myce-
lium. In ToRULA, one or more globular
cells are produced at the ends of filaments
composed of elonsfated, more or less cylin-
drical cells (PL 26. fig. 7) ; these globules
drop off, and develop into new mycelia. In
Botrytis (figs. 77, 78, 263), the tips of the

Fig. 26.3.

Fig. 264.

Botrytis (Polyactis) vulgaris.
Fertile filaments. Magnified ^00 diams.

fertile filaments are branched and clothed
with heaps of spores arising from short pe-
dicels. In PeniviUium (PI. 26. fig. 15), the
filament which rises up, forks at the end,
each branch forking again, and so on, until
a close tufted pencil of branches is formed,
each branch beai'ing a bead-like row of
spores, which drop off separately. Innu-
merable modifications of this mode of fruc-
tification are met with in the microscopic
Fungi ; and the same plan also forms the
basis of the fructification of some of the
highest forms.

The way in which the greater complexify
arises is by an increased development of the
structures supporting the layer of tissue
{/n/meniifvi) upon which the spores are
borne. Thus, in the leathery Fungi grow-
ing over damp trunlcs of trees and dead
wood, such as the Hydna, Thelephorce,
Hexagonia (figs. 264, 265), the conspicuous

licxagoma glabra.
Upper surface. Nat. size.

Fig. 265.

Hexagonia glabra. Ifat. size.
Lower surface, with orifloes of the hymenium.

fungous mass (which is all that ordinary
observers notice) developed from a floccu-
lent mycelium imbedded in the matrix on
which the plant grows, is a fruit, composed
of dense cellular tissue, and possessing pits,
channels, cavities, or the like, the walls of
whicli are clothed with papillose cells, each
bearing four free sporanges, which drop off
singly to reproduce the plant. The Mush-
room, as gathered and brought to table, is
merely the ' fruit ' of the Fungus {Agaricus) ;
and similar cells bearing four sporules are
found clothing the fiat sides of the paper-
like plates or 'gills' which radiate on the
under side of the flat 'cap' of the Fungus.
(See Basidiospores.)

A second kind of fructification is seen in
the Phycomycetes, where the upright
filament arising from the flocculent myce-
lium does not bear free spores as in Peni-
cilliiim, Botrytis, Sec, but a comparatively
large sac, filled with minute sporules; and
these sporidia are scattered by the bursting
of the sac. In the Helvellce, Pezizce, Sj)a-
thulea (fig. 40), Leotia (fig. 41), &c., struc-
tures of a fleshy or leathery character, grow-
ing upon damp wood &c., we have counter-
parts to the Hydna, TJtekpliorce, Sec, since
they have fruits arising from a flocculent

FUNGI.

[ 345 ]

FUNGI.

mycelium ; but their spore-beariug cells ap-
pear as detiiiite groups of vesicles or sacs of
elongated form, producing sporules (usually
eight but sometimes two, multiples of two,
or multiples of eight) in their cavities. In
the Truffles (Tuber, Elaphomyces, fig. 185),
&c. the sporidia are found in twos, fours, or
eights, iu sacs in the internal convoluted
substance ; while in the Puti'-jjalls, except
Scleroderma, where the internal mass finally
breaks up iuto powder, the spores are deve-
loped free, as in the Agarics &c. More
minute accounts of these structures will be
found under Thecaspores and the various
genera.

It was long imagined that these two
modes of producing the spores alforded a
firm basis for the classification of the Fungi ;
but recent discoveries seem to indicate that
characters derived from the fructification
are as unsafe here as in the Algaj. Thus,
if De Bary's observations on Agancus are
correct, an asciferous structure occurs in the
highest group of the basidiosporous classes.
It is now, however, pretty certain that the
ascigerous structure which he found on
Agaricus mellevs was a species of Ilypho-
myces. The orders Coniomycetes and As-
co'mvcetes also are confounded together by
the numerous genera which exhibit both
asci a,nd sfgtospores, although the latter may
perhaps be regarded as merely a modifica-
tion of the ascosporous structure. Tulasne
has also pointed out a peculiar structure
analogous to the so-called sj^ermatozoids of
the Lichens, namely very minute cylindrical
bodies growing upon free points from the
fructifjnng surfaces of the Fungi ; these
bodies, quite distinct from the basidiospores
and thecaspores, are called spermatia (PL 2(3.
figs. 3, 4, 17 s). According to Cornu, these
germinate.

Certain more recent observations on the
sexual reproduction of the Fungi require
special notice.

In the Saprolegnipe, this has been de-
scribed under Achlya. In Cystopus, the
conidia are stated to be formed at the ends
of the branches. Subsequently sporangia
or oogonia are produced by the swelling
of the ends of branches of the mycelium ;
while on another branch, a shoot grows to-
wards the sporangium, swells, and forms
an antheridium. A fine tube from this
bores through the sporangium, and pro-
duces fertilization.

In the Ascomycetes, a mycelium is formed
from the true spores ; on this are produced

conidia, which again produce mycelium,
Ou this are ultimately produced sexual
organs, consisting of the polUnodium or
antheridium, and the carpogonium or spo-
range : these are often much alike, but the
latter is usually larger, and composed of
more numerous cells. The pollinodium
forms a slender branched cell, not contain-
ing spermato/oids. It comes in contact at
the apex or through its whole length with
the sporange, which it fertilizes by diffu-
sion, as in the pollen-tube of the embrj'o-
sac ; but there is no fusion of contents.

In Ascobolus, the carpogonium or spo-
range consists of a curved row of cells.
The slender branches of the pollinodium
become closely applied to and fertilize it.
After this, one of the middle cells of the
carpogonium grows more than the others,
and produces buds which ultimately form
the asci.

In Peziza, the end-joints of the carpogo-
nial branches form ovate vesicles with an
apical appendage. The slender wedge-
shaped pollinodium arises on the same
branches beneath the carpogonium, with
which it becomes connected. Numerous
filaments then spring from the base of the
sexual organs, forming a dense network^
the hymenial layer, in which the asci are
subsequently produced. It appears that
Botryfis cinerea is a conidiiferous form of
Peziza (Fuckeliaiia). A remarkable pecu-
liarity in the sexual formation of spores iu
many Fungi, as in some Algse is, they are
frequently not formed in the directly ferti-
hzed cell, but in the newly formed cells
springing from its sides or base.

The sexuality of the Ascomycetes, how-
ever, is disputed.

Zoospores have now been discovered in
Pero^ospoba and Cystopus.

The minutias of the structure of the Fungi
may be treated most satisfactorily under the "
heads of the orders (Ascomycetes, Conio-
mycetes Sec), since the elements are very
similar in all, Avhile the modes of combina-
tion are very varied, and in most cases
peculiar to the families.

In consequence of the numerous disco-
veries of Tulasne, De Bary and others, tlie
older arrangement of the Fungi, based upon
the views of Fries, is not at present satis-
factory. We adopt, therefore, that of Sachs,
slightly modified ; retaining, however, in
great measure the nomenclature for those
Fungi which are manifestly merely states
of higher forms, and are not autonomous.

FUNGI.

[ 346 ]

FUSARIUM.

I. ScHizoMYCETES. Consisting of
threads which break up into minute cylin-
drical bodies, sometimes straight, some-
times curved, or microscopic globular par-
ticles ; in the former case, sometimes at
length swarming and forming a cloudy
gelatinous mass : in solutions or in decom-
posing substances.

II. Phycomycetes. Aquatic or epi-
phytous, propagated by zoospores, or by
oospores arising from fertilization.

1. Saproleynice. Aquatic.

2. Pero7iosporece. Epiphytic.

3. Mucorini, Fermentigerous ; Sapro-
phytic (Moulds).

III. ' Hypodeemle. Epiphyllous.

1. Uredinece. \ c, , r.

o rr ^ -7 • I bmutS iXC.

2. (Jstilaginece. \

IV. Basidiomy'cetes. Spores seated
upon Basidia or Sporophores arising from
a distinct hymenium.

1. TremelliiKB. Tissues gelatinous; hy-
menium exposed.

2. Hymenomxjcctes. Tissue cellular, hy-
menium inferior (Mushrooms &c.).

3. Gasteromycetes. Hymenium intri-
cate, cellular, internal (Puff-balls &c.).

V. AscojiYCETES, Sporidia contained
in Asci (thecse).

1. Protomyces. More properly perhaps
associated with Peronosporese.

2. TuberacecB. Hymenium as in Gas-
teromycetes (Truffles &c.).

3. Onyijenece. On animal substances,
very rarely on decayed wood.

4. Fyrenomycetes. Asci contained in
perithecia.

5. Discomycctes. Hymenium superior,
disciform.

VI. Myxomycetes. Spores amoeboid
in germination, subsequently conjugating.

BiBL. Berkeley, Fungales, Lindley's Veg.
Kingd, : Fuiigi, in Hooker's Br-. Fl. and
Crypt. Bot. ; also numerous papers in Ann.
N. H. ; Montague, Ann. N. H. ix. ; Corda,
Ic. Fung. 1837-40 ; Greville, Scott. Crypt.
Fl. ; Nees v. Eseubeck, Syst. Pilze ; Fries,
Syst.Myc. & Summa Veget.; Tulasne, i^tiw^.
Carp. 18(30-5; De Bary, Frucht. Ascomycet.
1863, 11 ; id. & Woroniu, Morph. S)-c. d.
Pilze, 1870 ; Tulasne, Ann. Sc. N. 1860, vi.
217; Janczewsky, Bot. Zeit. 1871; Fuisting,
Bot. Zeit. 1868; Baranetzki, Bot. Zeit. 1872;
Sachs, Bot. 1874, 307 ; Cornu, Ann. Sc. N.
1876 {M. M.Jn. xvii. 1877, 295); Tieghem,
Ann. Sc. N. 1875, ii. 365 (sexuality dis-
puted); Cooke, Br. Fungi, 1871 (descript.
of sp., ^' Jigs, of gen.) \ Brefeld, Schimmel-

2nlze, 1881 ; Bary & Woronin, Morph. d.
Pilze, 1881.

FUNGUS-BED.— Mycologists _ find this
very useful for growing the microscopic
Fungi. It is best made of a small wooden
box half-filled with damp bog-earth, and
covered with a plate of glass. In winter it
should be kept in a warm room.

FURCELLA'BIA, Lamx.— A genus of
Cryptonemiacese (Florideous Algae), cou-
taixiing one common British species, growing
on rocks and stones between tide-marks,
consisting of a fastigiate, dichotomously-
divided frond, 6 to 12" high, of a brownish-
purple colour, and somewhat cartilaginous
texture. The teti-aspores, which are linearly
arranged, are imbedded in the periphery of
the swollen pod-like extremities of the
branches. Conceptacular fruit as yet un-
known.

BiBL. Harvey, Mar. Alg. 147, pi. 18 C ;
P/iyc. Brit. pi. 94 ; Greville, Alg. Brit. pi.
11 ; Fnr/. Bot. pi. 894 ; Thuret, Ann. Sc. N.
1855, iii. 5.

FURCULARIA, Lam.— A genus of Ro-
tatoria, of the family Hydatinsea.

Char. Eye single, frontal ; tail-like foot
forked. Several species ; all freshwater but
one, Avhich is marine.

F. Reinhardtii, E. (PL 43. fig. 34: fig. 35,
teeth). Body fusiform, truncated in front ;
foot elono-ate, cj'lindrical ; toes two, short ;
length 1-120".

Found creeping upon Laomedea geni-
cidata.

F. gibha. Body oblong, slightly com-
pressed, dorsally convex, ventrally flat ;
toes stvliform, half as long as the body ;
length 1-96". Freshwater.

BiBL. Ehrenb. Infus. 419 ; Dujardin,
Inf. 648; Gosse, Ann.'N. H. 1851, viii. 199.

FUSA'RIUM, Lk.— A genus of Stilbacei
(Hyphoraycetous Fungi), not very satis-
factorily distinguished from Fl'Sisporium ;
but having a firm, cellular, pulvinate, fleshy
stroma, upon which thespoi'es are borne on
distinct sporophores glued together into an
erumpent discoid stratum. P. tremelloides
is common, forming roundish orange-red
spots on decaying nettle-stems ; but it is
now believed to be a spore-bearing state of
Peziza fusarioides. F. roseum forms little
gregarious red dots on the stems of beans,
Jerusalem artichokes, and other plants.

BiBL. Berk. Hook. Br. Fl. ii. pt. 2.
355 ; Fries, Syst. 3Ii/c. iii. 469, Sununa
Veg. 472;. Greville, Sc. Crypt. i=^/. pi. 20;
Fresenius, Beitr. z. My col. Heft 1. 35.

FUSIDIUM.

[ 347 ]

GAMASEA,

Fusisporiuin.

Spores. Magn.

400 diama.

FUSTD'IUM, Lk.— A genus of Mucediues
(Hypliomycetous Fungi), cliaracterized by
very delicate white or coloured llocci, wliich
do uot form a moist or gelatinous mass as
in Fusisjyoriion, and are very evanescent.
Spores straight, filiform. The species grow
on dead leaves, forming a thin powdery
stratum.

BiBL. Berk. Oidl. 357; Cooke, Bi\Fung.
609; GreviUe, Vnjpt. Fl. pi. 102.

FUSISPO'KIUM, Lk.— A genus of Sepe-
doniei (Hypliomycetous Fungi), growing
upon vegetable substances often when de-
canng, characterized by elou-
gate fusiform curved septate Fig, 266.
spores (fig. 206), which ul-
timately form a gelatinous
mass, the fiocci being in ge-
neral more or less obscure, or
if present very delicate, the
spores in fact forming the
principal element. Nume-
rous species are recorded as
British. J*', atrovirens is de-
structive to onions. F. betce
common on decaying mangold-wurzel. F.
fceni sometimes runs over the cut surface of
'a havstack,forming broad orange-red patches.

BiBL. Berk. Hook. Br. Fl. ii. pt. 2. 251,
Ann. N. H. vi. 438, pi. 14. fig. 28 ; 2 ser. vii.
178; Fries, S>/st. Myc. iii. 442, Sum. Veget.
473; GreviUe',*. Cnrpt.Fl.^l. 102. figs. 1&2.

FUSULl'NA, Fisch. — A genus of spiral,
hyaline Foraminifera, near Nonmiina and
Nummulina, hwi fusiform instead of uauti-
loid, the umbilical axis of the shell being
much extended. The lateral tapering elon-
gations of the chambers in some cases are
simple, yielding symmetrical casts figured
by Fhrenberg as Borelis in the ' Mikro-
geologie ; ' but in others the chambers are
divided throughout by labyrinthic segmen-
tation, giving more complex casts and sec-
tions.

F. cylindrica (PI. 24. f. 15) and its va-
rieties form enormous masses of limestone
in the Carboniferous system, in Russia and
North America.

BiBL. Carpenter, Foram. 304 ; M. Mic.
Jn. 1870, 180 ; Parker and Jones, Ann.
N. H. 1872, 260 ; Brady, ibid. 1876, 414 ;
MciUer, Foram. Buss. 1878.

G.

GALLIONEL'LA, Bory, = Melosiba,
Agardh.

Galls. — These are abnormal growths,
tumours as they might be called, produced

upon or in vegetables by the action of ani-
mals, especially insects of the order Hyme-
noptera. They were supposed to arise from
the irritation caused by a poisonous liquid
discharged into the orifice made by the
insect for the introduction of its egg. At
all events a convergence of the nutritive
juices towards the wound takes place,
whence results a kind of hypertrophy of the
tissues, and frequently the accumulation of
such substances as starch in the cells. The
forms may be regidar or irregular ; most of
them are characteristic, as, for example,
the well-known nut-gall, the oak-apple,
the bedeguar of the rose, &c. Both cellular
and vascular structures contribute to form
the substance of galls. We cannot enter
into their minute structure here, but refer
to an elaborate paper by Dr. Lacaze-Du-
thiers and to Adler's more recent memoir,
Adler's plates will enable the identification
of most, if not all, the British oak-galls,
and will perhaps lead to the discovery of
others. See Aphidje, Cynipid^, and
Phytoptid^,

BiBL. Lacaze-Duthiers, Ami. Sc. Nat,
3 ser. xix. 273, where also the earlier lite-
rature is given ; Adler, Zeitschr. wiss. Zool.
liii. 151 ; M'Lachlan, Fnt. Mn. Mag. 1881,
xvii. 259.

GALUM'NA, Heyden, Gervais.— A ge-
nus of Arachnida, of the order Acariua, and
family Oribatea.

Char. Abdomen subglobular, depressed;
sides of the pseudo-thorax forming a salient
or wing-Uke angle ; legs of moderate length.

This genus approximates to Belba.

The three species, the bodies of which
are of a blackish, blackish-chestnut, or ash
colour, are found on mosses.

BiBL. Walckenaer, Arachn. (Gervais) ;
Hermann, Mem. ApUr. 91 ; Koch, Deidsch.
Crusfac. &c.

GAMA'SEA.— A family of Arachnida,
of the order Acariua.

Characterized by the free fihform palpi,
the chelate mandibles, and the 7-jointed
legs with two claws and a caruncle. Gene-
rally parasitic, and found on insects and
birds; some upon fishes, reptiles, and
mammals ; eyeless.

Dermanyssus. Body soft; last joint of
palpi smallest ; labiunl acute ; mandibles — •
of male, chelate, outer claw very long, — of
female, ensiform ; legs with two claws and
a caruncle, anterior longest, coxae approxi-
mate. On bii-ds and bats (PI. 6. fig. 24).

Gamasus. Body hard ; labium tritid ;

GAIMASUS.

[ 348 ]

GASTEROMYCETES.

body -with usually two dorsal plates ; an-
terior legs generally longest, second pair
sometimes incrassate 5 no eyes. On insects,
&c. (PL 6. fig. 20).

Pteroptus. Body depressed ; last joint
of palpi longest ; legs stout, with short
joints. On bats (PI. 6. %. 39).

Uropoda. Body depressed, with a round
dorsal plate, and a deciduous funnel-shaped
anal peduncle, serving to fix the body. On
beetles, mosses, &c. (PI. 6. fig. 25).

HaJarachne. Body elongate, with a dor-
sal and ventral plate ; labium bifid. In the
nostrils of a seal [Halichoerns) .

See also Argas and Caeis.

BiBL. Gervais, TJ'alcJienaer\s Apt. iii.
215 ; Duges, Ann. So. Nat. 2 ser. 24 ; Koch,
Deutsch. Cnistac. and UehersicJit ; Murray,
Ec. Entom. 157; Megnin, Paras. 11-3;
Kramer, Wieqm. Arch. 1876, i. '2S; Tr.
Mic. Soc. 1880, 177.

GAM'ASUS, Latr. — A genus of Arach-
nida, of the order Acarina, and family Ga-

JIASEA.

Species numerous ; mostly parasitic upon
insects ; some found upon the ground ;
others on the higher animals.

G. coleoptratorum (PL 6. fig. 26). Found
upon dung-beetles {Geotrttpes &c.). An-
terior coxae attached at a little distance from
those of the second pair ; tarsi (fig. 26 a)
with two claws and an elegant caruncle ;
palpi of moderate length ; mandibles ter-
minated by a curved hook ; fawn-coloured.

G. marginatum. Body laroader behind ;
darker. Found in the human brain; also
on a fly, and on beetles.

G. mtiscarum. On the house-fly,

G. auris. In aural meatus of ox.

Other species.

BiBL. That of the family ; Leidv, Proc.
Acad. PkU. 1872 {Ann. N. II. 1873, xi.
79) ; JMurray, Ec. Ent. 158.

GAM'MARUS, Latr.— A genus of Crus-
tacea, of the order Amphipoda, and family
Gammarina.

The searcher for the freshwater ]3iatoma-
cepe will surely meet with Gammarus pidex
(PL 18. fig. 22), the freshwater shrimp, in
muddy brcioks and streams. It attains a
length of about 1-2", and moves its curved
body through the water by menus of its
caudal appendages, frequently lying on its
back or side during the process. Gervais
distinguishes G. ^//nviafilis from G. jmle.v,
by the former having a dorsal spine at each
abdominal joint, whilst in the latter this is
absent.

There are twenty-three species of Gam-
marus, many of them marine. Taliti'us sal-
tator, the sand-hopper, found burrowing in
and hopping upon the sand of the sea-shore,
also belongs to the family Gammarina.

BiBL. Besmarest, Consid. gen. Crust. ;
M.-Edwards, Crustac. iii. ; Gervais, Ann.
Sc. Nat. 1835, iv. ; West wood, P/«7. Tr.
1835 ; Bate and Westwood., Ann. N. H.
1857, xix. 135; Rentsh, Gatnm. orn. 1861.

GANGLION-GLOBULES, or nerve-
cells. See Nerves.

GAPES. — Achsease occurring in poidtry,
arising from entozoa {Sclerostoma and
Sgngamus) in the air-passages.

GAPtVEI'A, T. S. Wright.— A genus of
Hydroid Polypes, fam. Atractylidse.

G. nutans. Body red, tentacles yellow ;
marine; height 1" On rocks and sea-weeds.

BiBL. Hiuoks, Brit. Zooph. 101.

GASTEROMYCE'TES. — A tribe of
Basidiomycetous Fungi, characterized by
the production of their free spores upon
basidia seated on a sporiferous structure
forming convolutions in the interior of an
excavated fruit, which ultimately bursts to
allow the sporiferous structure to expand
and scatter its spores. The fruit of the
Gasteromycetes is ordinarily a globular,
elliptical, or shapeless mass, varying in size
from microscopic minuteness to the dimen-
sions of large balls, often stalked, arising
from an inconspicuous fiocculent mycelium.
This external body consists of a leathery or
membranous, simple or double sac \pe-
ridium), which bursts in various ways at
maturity. When examined young, these
Fungi appear solid ; but as they advance,
various structures become gradually marked
out in their interior, and appear more and
more distinct until mature.

In the Nidulariacei little conceptacles are
developed in the interior of the sac-hke pe-
ridium ; and when the latter is mature, it
opens like a cup or vase at its summit, ex-
hibiting the conceptacles within, lying like
eggs in a nest. These conceptacles are
hollow, and lined with basidia bearing free
spores.

The Trichogastres exhibit in most cases
the appearance of a leather ball, arising
from an inconspicuous fiocculent mycelium ;
but in Broomcia the peridia are imbedded
in large numbers in a common fleshy matrix.
The internal structure diflers to a consider-
able extent in its earlier stages. The peri-
din m is either single or double, the outer
being often quite free, and becoming everted

Fig. 268

GASTEROMYCETES.

Fiff. 2G7.

[ 349 ] GASTEROMYCETES.

Polysaccum crassiped.
Fig. 267. Natural size.
Fig. 268. Section from ditto, showing the loculi.

Polysaccmn erasaipes.

Cells of the hymenium, with basidia and spores.

Magn. 400 diams.

at the time of dehiscence. The interior of
PoJysaccum (fig. 268) and Scleroderma (fig.
270) consists, in the early state, of a mass of
cellidar matter, formed by the prolongation
of the peridium, in the form of septa, in all
directions into the interior, so as to divide
it into chambers, each of which is lined
•with a hymenium or conceptacle, hollow in
the centre, into which project the ends of
the filaments, bearing basidia with two to
six spores. At the epoch of maturity all
the internal structure has vanished, except
the spores and detached particles of the
filaments on which they were developed ;
and these escape, on the iDursting of the now
bag-like peridium, as a fine powder. In
Lyc&perdon, &c., it is not the peridium

Fig. 270.

Fi- 271.

f^"^ IfS^

Scleroderma rulgare.

Fig. 270. Portion of the internal mass. Magn. 200

diams.
Fig. 271. Cells of the hymenium, with basidia and
spores. Magn. 400 diama.

which is continued inwards to form cham-
bers ; it forms a single or double sac, con-
taining a fleshy substance (gleba), hollowed
out into sinuous cavities clothed with
basidia. In course of ripening, the spongy
mass disappears, leaving only a collection
of minute spores and filamentous fragments,
which are emitted by the bursting of the
peridium, — a process exhibiting many cu-
rious peculiarities in this group.

The Phalloidei are roundish or ovoid
fleshy balls in their earher stages, but when
opened exhibit a distinct peridmm and a
central lacunose sporiferous structm-e. The

Fig 272.

Lycoperdpn ceelatum.

Section of the gleha showing the loculi, on the walls of

which the spores are produced.

Magn. 200 diams.

peridium consists of two layers, an inner
and an outer, united by firm gelatinous

GASTEROMYCETES.

[ 350 ]

GASTEROMYCETES.

Fig. 273.

Clathrus
cancellatus.

tissue traversed by transverse membranous
septa, and exhibits a tendency to split, like
an orange, into quarters. When
the peridium bursts, which it
usually does at the apex, the
central sporiferous structure
emerges, under various forms.
In Phallus it is a capitate or
clavate column ; in Clathrus
(fig. 273), an elegant, globular,
fleshy trellis ; in Aseroe, a co-
lumn with a stellate bead, &c.
In all cases, the spores, Avhicb
are developed on convolutions
of the fleshy sporiferous mass
(ffleba), on tjasidia, are found The sporiferous
detached and confluent into a ^'^'^^'^ : ^'•^'"'^

, • • 1 11 . , ji eniereed from

wet Viscid mass aahermg to the the ruptured
sporiferous surface at the time peridium.
this has emerged from the ^-^"^'^ °^'^- '^^•
peridium and expanded to its full size.
This wet condition of the mature sporife-
rous layer is distinctive between the Phal-
loidei and the Hymenomycetes, to which
they bear many relations.

The ITypogaei receive their name from
tbeir subterraneous habit of growth; in
which they resemble Truffles, a tribe of As-
comycetes bearing much external similarity
to these plants (see Tuberacei). The
general character is that of globular or de-
pressed balls, growing underground, sessile
on a flocculent mycelium. They exhibit a
peridium enclosing a fleshy r/leba, excavated
into sinuous cavities lined by a membrane
bearing basidiospores. Tliese fruits do not
burst, but set free their spores by decaying.

Lastly, the Podaxinei bear much resem-
blance to the Trichogastres ; but they always
contain a central fleshy column, called the
hymenophore. The yoimg plants exhibit a
peridium passing internally into a fleshy
mass hollowed into labyrinthiform cavities
(fig. 275), with a solid column in the centre
of all. The cavities are lined by a mem-
brane bearing basidiospores (fig. 277). The
gleha sometimes breaks up into a pulverulent
mass of spores and filaments ; sometimes it
is permanent. The internal structiu-e of
this order presents many points of gi-eat
morphological interest, but rather as regards
the mode of arrangement and composition
of the tissues than the character of the ul-
timate elements themselves, which consist
of the ordinary filamentous interwoven tis-
sue of Fungi in the general mass of the
structure, and of globular loosely packed
cells in the sporiferous regions.

Fiff. 274

Fig. 275.

Secotium erythrocephalum.

Fig. 274. Natural size.

Fig. 275. Vertical section.

Fig. 276. Vertical section through the head, showing
the labyrinthiform cavities.

Fig. 277. Portion of a septum dividing the loculi, bear-
ing basidia. Magnified 400 diameters.

Synopsis of the Families.

Podaxinei. Peridiutn dehiscent, en-
closing a sinuously excavated, fleshy, spori-
ferous mass, falling to powder or permanent
when mature, with a central solid column.

Hypogjei. Pendium indehiscent, coat-
ing a fleshy, sporiferous mass. Subter-
raneous.

Phalloidei. Peridium dehiscent, en-
closing a fleshy, sporiferous mass, which
emerges from the burst peridium as a club-
shaped or capitate column, or a globular
network of wrinkled fleshy precesses, coated
on the sporiferous surfoces with a dark-
coloured foul-smelling .slime (composed of
minute spores imbedded in mucus).

Trichogastres. Peridium double, more
or less distinct, dehiscent, enclosing a mul-
tilocular, fleshy, sporiferous mass, which
finally breaks up into dust, without a cen-
tral column.

CtASTROCH.ETA.

[ 3ol ]

GENEHATIONS.

NiTiULATJiACEi. Peridium dehiscent, and
then fonuinfr a cup or upst, containing one
or many globose, oval or discoid concep-
tacles, lined with iilanients bearing spores.
Btbl. See the Families.
GASTROCILE'TA, Duj.— A genns of
Infusoria, of the family Enchelia (Uuj.).

Char. Body oval, with one side convex,
the other being traversed by a longitudinal
furrow, which is furnished' with vibratile
cilia, priucipallv at the ends.

G.fssa (PI. 3] . fig. 7). Body semitrans-

parent, colourless, oval, ti-micated in front,

with a very minute blunt point at the

middle of the posterior margin, convex and

smooth above. Freshwater; length 1-400".

BiBL. Duiardin, Infus. p. 38.5.

GAUDRVI'NA, D'Orb.— a Textularian

Foraminifer, having the early chambers

arranged triserially, as in a Vei-neuilma,

makino; the sheU three-keeled at first ; but

it subsequently becomes compressed and

•wrinkled, the' chambers being alternate

with biserial growth, as in Texfidaria. The

aperture is usually, as in Texfidaria, a slit

on the inner wa'U of the chamber ; but it

niav be almost terminal and somewhat

rounded and pouting, thus passing into_.He-

terostomeUa. Some Gaudryince. are twisted

and Buliminoid. Fossil and recent. PI. 23.

fig. 48, G. pvpoidcs, D'Orb., in the Chalk.

BiBL. D'Orb. For. Foss. Vim. ; Parker &
Jones, Annals N. H. ser. 3, xi. 127.

GELATINE.— This chemical proximate
principle constitutes the basis of the various
forms of connective tissue, as existing in
the true skin, areolar tissue, tendon, liga-
ments, the swimming-bladder of fishes
(isinglass) ; also of bone &c.

It possesses no microscojiic characters ;
it forms a most valuable vehicle for the
colouring-matters of liquids for injection.

GELID'IUM, Lamx.— A genus of Cry-
ptonemiacese (Florideous Algse), of which
one species {G, corneum) is very common
on our shores. It has a red, pinnated,
homy frond, from two to six or eight inches
high ; very variable in the appearance of
its pinnate subdivisions; both spores and
tetraspores are found on the ramules, the
former in faveUidia immersed in swollen
ramules.

BiBL. ITaiweT, Mar. Alg. 137, pi. 17 B,
Fhyc. Brii. pi. 53.

GEMELLA'PJA, Sav. — A genus of
Cheilostomatous Polyzoa, of the order In-
fundibulata, and family Gemellariid*
(Eucratiidse, H.)

G. lorictdata (PI. 86. fig. 26). CeUs in-
versely conical, obliquely truncate. Com-
mon a few fathoms Ijclow low water-mark.

BiBL. That of the family.

GEMELLA'RIID/E.— A family of Chei-
lostomatous Polyzoa, of the order Infundi-
bulata.

Distinguished by the unjointed zoary,
and the cells being opposite in pairs. Two
genera :

GemeUaria. Cells jointed back to back,
all the pairs facing the same way ; orifice
oval, oblique ; no birds'-heads (PI. 36.
fig. 26). . .

Notamia. Each pair of cells ansmg
from the next pair but one below it by
tubular prolongations ; pipe-shaped birds'-
heads above each pair (PI. 36. fig. 21).

BiBL. Johnston, Br. Zooph. 293 ; Busk,
Mar. Polyzoa, 34 ; Gosse, Mar. Zool. ii, 14 ;
Hincks, Polyz. 17.

GEMMiE. — This term is applied to those
cellular structures, formed in Flowerless
Plants, which become detached, and repro-
duce the individual independently of the
spores.

GEMMULI'NA, D'Orb. See Bige-

NEEINA.

GENERATIONS, alternation of.—
The ordinary plan upon which the repro-
duction of animals is elFected, viz. that of
sexes, involving the action of the spermatic
secretion upon the ova, and the subsequent
series of changes ultimately giving rise to
new individuals resembling the parents, is
in some instances departed from ; and the
embryos of certain animals, after their escape
from the ova, do not become directly de-
veloped into individuals resembling the
parents, but produce a new, larval kind of
being, which produces generations of the
same larval or other kinds, the last of which
resemble the original parents.

"While, therefore, in animals reproduced
by the ordinary sexual process, the new in-
dividuals resemble each other, or differ only
in sex, in those which produce these alter-
nate or intermediate generations the new
individuals differ from the parents and even
from each other, until the last of the series
returns to the state of the first parents.
This mode of reproduction has received the
above name, from ~ the alternation of the
larval generations with the ordinary sexual
form.

Many instances of this process are men-
tioned under the heads of the Classes &c.
in which they occur ; as under Acaxeph^,

GENERATIONS.

[ 352 ]

GENERATIONS.

Aphit)^, Entozoa, T^nia, &c. Thus,
for instance, iu the Acalephse, the ciliated
embryo (PI. 49. fig. 6) produced by the
ordinary sexual process becomes fixed (fig.
7), and passes into the state of an asexual
polype (fig. 8) ; it then reproduces new
individuals from gemmae and stolons (fig. 9),
ultimately becoming segmented (fig. 10),
and producing new individuals which re-
semble the sexual parents. The interme-
diate or nurse forms are those represented
in figs. 7-10. Again, in Tcenia, the Ci/sti-
cerciis or Echinococcus forms the nurse, pro-
ducing new individuals bj'' gemmation, these,
on reaching the alimentary canal, becoming-
transformed into Tcsnice with sexual organs.

But the alternation of generations, or a
modification of it, also occurs in animals in
which sexes are not known to exist, as in
some Infusoria and Rhizopods. In these,
the ordinary plan of reproduction by di-
vision and gemmation is departed from,
and an animal difl'ering from the parent, or
a nurse-form res^embling or identical with
Acineta and Act inoj)hri/s, is produced, which
gives rise to embryos subsequently growing
into the parent form. But in these in-
stances the nurse-form is the result of a kind
of metamorphosis, rather than of generation.

In the Aphidfe, the process is exhibited
by the repeated formation of viviparous
broods of beings, from apparently female
insects, without impregnation, the final
progeny being sexual. This is called par-
ilienogenesis.

The phenomena designated by the phrase
alternation of generations are also strikingly
exemplified in the vegetable kingdom; but
the conditions are A'ery complicated, and the
an.ilogics with those occurring in animals
somewhiit difficult to trace. The Mosses,
Hepatica;, and Ferns afford very clear
analogies to the Medusae ; and others admit
of being made out ; but it appears to us that
Steenstrup and others have confounded va-
rious distinct points, in the parallel drawn
between the alternation of generations of
animals and the metamorphoses (commonly
so-called) of plants. We will endeavour
to give a summary of the general facts
connected with the doctrine.

1. All animals and plants reproduced by
a sexual process (and there is reason to
believe that this will ultimately be found
universal), originate from a simple proto-
plast or cell, and undergo a series of changes,
m the course of their development to the
complete form endowed with sexual organs,

in which they assume forms analogous to
animals ( or plants) belonging to classes of
lower (simpler) organization.

2. In the highest animals, the metamor-
phoses ai'e intra-uterine, as iu most of the
Mammalia ; in the lower animals these
metamorphoses are in part or wholly extra-
uterine. In the higher plants the changes
are partly intra-uterine (i. e. the embryo has
already become a leafy axis within the
ovary, but it becomes perfected into the
sexual form subsequently), in the lower
partly or wholly extra-uterine.

3. The lower animals and all plants are
capable of an asexual or vegetative repro-
duction, by the isolation and separation of
a portion of their substance.

4. Many animals and all plants are ca-
pable of being multiplied by this vegetative
reproduction in their intermediate stages of
extra-uterine development ; and in such cases
the reproduction, fissiparous, gemmiparous,
or other, assumes the character peculiar to
the class to which the intermediate form is
analogous (e. g. the polypifonn reproduction
of the Acalephse, the coufervoid growth
and multiplication of the proembryo of the
Mosses). The product of the vegetative
reproduction is either like or unlike tlie
body which produces it : in the former case
the vegetative reproduction will be re-
peated ; but in the latter case the product is
usually provided with sexual organs, and
the cycle of development is completed by
the reproduction of a fertilized ovum. In
the latter case we have what is called an
alternation of generations.

It will be evident that we here exclude
from consideration the metamorphoses
within the sphere of the individual shoot on
plants — that is, the metamorphosis of the
leaf, the morphological element of the higher
plant. It appears to us that these are not to
bo taken as parallels to the metamorphoses
of animals comprehended by Steenstrup
under the name of alternation of genera-
tions, which would rather be found in the
cases where bulbs, bulbils, tubers, &c. ap-
pear in the place of shoots, as the product
of branch-buds. The analogy would hold
also with the gemmcp of the Mosses, &c., and
with the govidia of the Thallophytes. Our
space does not admit of a more minute exa-
mination of the subject. Illustrations of
the phenomena in vegetables will be found
under Fehns, Mosses,. CoNrERvoir>E^,
Lichens, certain Fungi, e. g. Eeysiphe,
Penicjllium, &c.

GENERATION.

[ 3.>3 ]

GEPIIYllIA.

Strictly speaking, the torm alternation of
generations is incorrect ; the process really
consisting of an alternation of reproduction
by gemmation, with that by sexual repro-
duction.

BiBL. Steenstrup, Altern. of Gen. {Bay
Soc. 1845) ; Owen, Parthowgcm'sis, and Ann.
N. 11. 18.")1, ii. 5i); A. Thomson, Cycl. An.
iv. Suppl. ; liraun, Rejuv., Hay Soc. 1853 ;
Heufrey, Ann. N. H. 2 ser. ix. 441; Radlko-
fer, Befrucht. 1857, Ann. X. H. 2 ser. xx.
241 ; Huxley, Inv. and T'erteb.; Leuckart
{Cecidomyia larvce), Ann. N. H. xvii. 18G6,
IGl ; Sachs, Bot. 227; Nicholson, Zool.
1878, 3.3.

GENERATION, spoxtaneous ; some-
times called equivocal generation, epige-
uesis, or heterogeny.

The doctrine of spontaneous generation
was considered to have become a matter of
history, ^^'e noticed under Air (p. 24), the
experiments which were supposed to have
negatived the idea that microscopic plants
and animals derive their origin from the
direct transformation of decaying animal
and vegetable remains. We have also there
stated the modes by which the lower forms
of organic life, most commonly found in de-
composing infusions, propagate with extra-
ordinary rapidity. More recent experi-
ments have shown conclusively that this
doctrine is untenable.

The supposed occurrence of particular
species of Entozoa within the bodies of
other animals, not to be found in any other
situations, was formerly considered to find
a ready explanation in the doctrine in ques-
tion. Later investigations, however, have
proved that these supposed species are larval
or other forms of tiue species of this Class,
which do not attain their perfect develop-
ment on account of their not existing in a
suitable locality.

BiBL. Schultz, Fogg. Annal. xli. 184;
Helmholtz, Jn. prak. Chem. xxxi. 429 ;
Gross, tSieb. unclKoll. Zeits. iii.G8; Reissek,
Ber. Wien, 1851 ; Pineau, Ann. 8c. Nat.,
Zool. 1845, 1848; Pasteur, Compt. Bend,
1860, U. 348, 675, and 1861, lii. 1142;
Pouchet, Heterogenie, 1859 ; id. Nouv. Exp.
1864 ; Bastian, Begimiinys of Life, 1872 ;
Evolution of Life, Med. Press and Circular,
1872: Tvndall', Putrefaction, 1881.

GENICULA'RIA, De Bary.— A genus
of Desmidiaceae.

Char. Cells cylindrical, elongate, neither
constricted nor incised, united into long
filaments. Eudochrome forming 2 or 3

spirals (left-handed). Conjugating joints
geniculate.

a. spirota'uia (PI. 51. iig. 36). Cells
slightly expanded at the ends, cell-walls
rough. Erankfort.

BiBL. De Barv, Conjug. 77 ; Rabenhorst,
Fl. Alg. iii. 156; Pritcliard, Inf. pi. W. tig. 31.

GEO'DIA, Lamk. — A genus of marine
sponges. Distinguished by the rounded
form, the solid structure permeated by
sinuous canals, and the solid external crus-
taceous covering formed of globules of silex.

O. Zetlandica. Deep water.

BiBL. Bowerbank, Brit. Spong. ii. 4o.

GEOLOGY. — The microscopic investiga-
tion of geological products is treated of
under Rocks.

GEOPHTLUS, Leach. — A genus of
Chilopodous Myriapoda.

G. longicornis, with the body brownish-
yellow, slender, consisting of more than 40
joints, is common in garden-mould, under
flower-pots, &c. G. subterrnneus is phospho-
rescent. See Myriapoda.

GEOR'GIA, Ehrh.— A Fig. 278.
genus of Muiaceous Moss-
es, called, from the four
teeth of the peristome,
TetrapJiis and Tetrodon-
tium ; but these names are
of later date thanEhrhart's
(1780). G. Mni'inos^jne
presents, besides its male
and female inflorescence,
a peculiar form of terminal
leafy bud (fig. 278), which
produces stalked gemmae
in the interior. In tlie
figure, numerous arche-
gouia are also shown.

Georgia Browniana,
C. Mliller, = Tetr aphis
Broion., Grev.

G. Mnemosyne, Ehrh.
= Tetraphis ^Je//«ciV/rt,
Hedw.

GEPHYRTA, Arn
macese.

Char. — Fr. arcuate, attached, destitute of
cellulate annuli and septa ; hoop sublanud-
late, finely striate. Valves arcuate, with
one median and several lateral costae, dis-
similar ; inferior with the costse disappear-
ing below the ends of the valve ; superior
with them reaching the summit.

G. incur vata. Ichaboe and Patngonian
guano.

Georgia Muemosyne-

A shoot with two
terminal leafy buds.

Magn. 15 diameters.

-A genus of Diato-

G. media.

Californian guano.

2 a

GERANIUM.

[ 351 ]

GILLS.

G. Telfairm. Mauritius.

BiBL. Arnott, Qu. Micr, Jn. viii. 20 ;
Greville, Micr. Tr. 1866, 77, 122 (tig.)-

GERA'NIUM.— Tile sepals of the com-
mon wild Geraniums and the garden Pelar-
gonia form pleasing objects when dried and
mounted in Canada balsam, the cells con-
taining regularly arrani;ed raphides (Que-
kett, Ann. N. H. 1846,'xviii. 82).

GER'DA, CI. & L.— A genus of Infuso-
ria, fam. Vorticellina,

Char. Sessile, resembling Sqfphidia, but
distinguished by the absence of the pos-
terior sphincter or sucker,

G. glans (PI. 52. fig. 2). — Body elongate,
cylindrical or clavate behind ; contractile
vesicle posterior, continued into a long ves-
sel. Freshwater.

BiBL. Clap. & Lachm. Infiis. 117 ; Kent,
Inf. 657.

GERMINAL VESICLE of Animals.
See Ovusr.

GERMINAL VESICLE of Plants.—
This structure, the existence of which is
now universally admitted by physiological
botanists, is the germ of the future plant,
formed from one of the protoplasmic germ-
massesi which exist before impregnation
(Tula sue is doubtful whether before) in the
embryo-sac of Flowering Plants. In most
cages' three masses are originally produced,
as in Orchis (PI. 47. fig. 4) ; and in rare
instances two of these are fertilized, and two
embryos produced in one seed; sometimes
only one exists, and ordinarily only one is
fertilized. This becomes at first elongated
into a cellular filament called the sxspeiisor,
wliich is cut oft' by septa into several cells,
the last of which usually becomes the
embryonal vesicle or embrgo-cell, which is
then developed into the embryo (fig. 192,
pa'^e 280). See Ovule and Embryo.

GERMINATION.— The act of develop-
ment of a seed or spore into a new pi int.
The phenomena attending the gerrainatim
of all the Cryptogamic plants require the
aid of the microscope for their investiga-
tion, and are in most instances highly in-
terest ii^ig and important in a physiological
point of view. For particulars, see the
classes of Flowerless Plants.

GER'RIS, Latr.— A genus of ITemipte-
rous (Ileteropterous) Insects, of the family
HydronietridfB.

Gerris lacitstris is everywhere seen skim-
ming the surface of water. It has the basal
joint of the antennas longest, the four liind
legs very long and at a great distance from

the fore legs. The legs do not possess any
special structure by which they are enabled
to repel the water, beyond a number of
short hairs.

Velia rifulorum, with the basal joint of
the antennae longest, the legs of moderate
length and equally apart, and Hgdromi-tra
stagnoruin, with the first and second joints
of the antennfe short, the third being the
longest, are allied members of the same
family, and are commonly met with on the
surface of pools, &c. The elegantly sculp-
tured eggs, and the curiously placed eyes of
Hydrometra, are interesting objects.

In the anteriortarsi of Velia, minute mem-
branous retractile lobes have been described.

Bibl. Westwood, Ixfrod. ii. 4G7, and
Si/n. 119; Douglas and Scott, Brit. Hemipt.
■ GIGAR'TINA, Lamx.— A genus of Cry-
ptonemiaceae (Florideous Algae), with car-
tilaginous irregularly-divided fronds, the
internal substance of which is composed of
rather lax tissue, the outer of dichotomous
filaments perpendicular to the surface,
strongly united by their moniliform termi-
nations (fig. 279). Four British species are

Gigartina iiistillata.

TransTerse section of tlie frond.

Magnified 50 diameters.

known, growing from 2 to 6 inches high,
of a dull purple colour. Reproduced by
spores (in favellidia) and tetraspores scat-
tered among the peripheral filaments.

G. acicularis (PI. 4. fig. 17).

Bibl. Harvey, Mar. Alga;, 139, pi. 17 C ;
Greville, Alg. Brit. 146, 147, pi. 16.

GILLS OF Fishes. — These organs form
beautiful and favourite injected objects.
They must be injected from the heart, or
from the branchial artery, which ascends

GILLS.

[ 355 ]

GLANDS.

from the lioart much in the same manner
as the pulmonary artery ascends from the
heart of the higher animals. It may be
remarked that the heart of tishes is situated
nmch nearer to the anterior end of the body
than in the Mammalia.

liiBL. Stannius, J'erc/l. An.\ Lerebonl-
let, An. Com]), de I'Appar. liespir. ; Ilyrtl,
Med. Jahrb. (Ester. iSfaat. bd. 24 ; Leydig,
Jlinfol. '.iS2 ; Gegeubaur, Veiyl. An. 505.

GILLS OF IxsKCTS, or brauchife. — These
are hair- or leaf-like processes (I'l. 35. figs.
2 //, 15, 19, 21) projecting from the surface
of the body, and containing one or more
traciicaj and their ramifications, which
commmiicate with those of the body gene-
rally. Insects furnished with gills or Ijran-
chiae have no occasion to rise to the surface
of the water in which they live, the diffusion
by which the respiratory process is effected
taking place between the gaseous contents
of the tracheae and those of the water,

GlXAN'iSIA, Montague. — A genus of
Cryptonemiacese (Florideous Algaj), con-
taining one British species, G.furcellata, a
rare, pinky-red sea-weed, about 2 to 0 in-
ches long, with a dichotomous, terete, mem-
branaceo-gelatinous frond, the divisions of
which have a kind of fibrous axis. The
spores are produced in spherical coucep-
tacles imbedded just beneath the surface of
the frond.

BiBL. Harvoy, Mar. Algce, 148, pi. 19 C ;
E. Botany, pi. 1881.

GINGER. — This substance finds a place
here on account of its liability to adultera-
tion when sold in the form of powder. It
consists of the rhizomes of Zimjihcr offi-
cinale (N. O. Zingiberaceas) . The bulk of
the structure consists of parenchymatous
cellular tissue with pitted walls, containing
scattered starch-granules, and here and
there filled with a combined mass of starch-
granules and yellow coloming-matter of
very distinct character ; besides these, occur
the pitted ducts and a small quantity of
woody fibre. The starch-grains nearly re-
semble those of the species of Curcuma
which yield East-India arrowi-oot. Adul-
teration is effected with cheap starches
(sago-, wheat-, or potato-fiour), which may
be detected by the form of the granules ;
while MusTABD-husks and Cayenne pepper
are employed to give pungency to the same
reduced articles. The characters of these
substances are given under their respective
heads.

BiBL. Hassall, Food ^-c. p. 390.

GLANDS OP Antmat.r. — Glands are
organs, the general function of which is to
separate from the blood certain compounds
destined to perform some special oliice in
the economy. They are divided into true
or secernent glands ; and vascular glands.

The secernent glands, the secretions from
which esca])e either by rupture, or through
ducts, are thus arranged : — ■

1. Glands consisting of closed vesicles
which dehisce laterally : the Graafian vesi-
cles of the ovary, and the follicles (Nabo-
thian) of the cervix uteri.

2. Glands composed of cells reticularly
united : the liver. (See Liver.)

3. Racemose or aggregated glands, in
which aggregations of roundish or elongated
glandular vesicles occur at the ends of the
excretory ducts. These are either, ff, sim-
ple, with one or but few lobules, comprising
the mucous glands, the sebaceous and the
Meibomian follicles ; or, b, compound, with
many lobules, the lachrymal and salivary
glands, the pancreas, the prostate, Cowper's
and the mammary glands ; in this category
must also be placed tfie lungs.

4. Tubular glands, in which the secreting
elements have a moi'e or less tubular form.
These are either, a, simple, consisting of
one or but few cascal tubes — including the
tubular gastric and intestinal (Lieberkiihu's),
the uterine, sudoriparous and ceruminous
glands ; or, 6, compound, consisting of nu-
merous reticular or ramified glandular canals
— comprising the testis and the kidney.

The vascular glands, which have no
ducts, and the contents of which escape by
transudation, are subdivided into —

1. Those composed of large and small
cells imbedded in a stroma of connective
tissue ; comprising the snpra-renal capsules,
the anterior lobules of the pineal gland, and
the pituitary body.

2. The closed follicles, consisting of a
basement-membrane, an epithelial lining,
and transparent contents, forming the thy-
roid gland.

3. The closed foUicles, with a capsule of
areolar tissue and contents consisting of
nuclei, cells, and liquid, to which belong, a,
the solitary follicles of the stomach and
intestines ; b, the aggregated follicles of the
small intestines, 'or Peyer's glands, in ani-
mals also those of the stomach and large
intestines; c, the glandular follicles of the
root of the toiigue, and of the pharynx and
the tonsils ; and, d, the lymphatic glands.

4. Here belongs the spleen, consisting of

2a2

GLANDS.

[ 356 ]

GLANDS.

a cellular parenchyma containiug numerous
closed follicles like tbe last.

5. The thymus gland, in which aggre-
gated glandular vesicles open into a com-
mon closed canal or wide space.

The glands are further noticed under
their respective heads.

BiBL. Kolliker, Mik. An., and Gew('be-
lehre ; Henle, AUg. An. ; ^^^ag•ner, Handw.
Phys. ; Todd and Bowman, Phys. Anat. ;
Carpenter, Physiol. ; Frey, Histol. 374.

GLANDS OF Plants.— The glands of
plants are special structures formed of cel-
lular tissue, in which are produced secretions
of various kinds, such as oils, resins, &c.
They are ordinarily more or less closely
connected with the epidermal tissues, but
not in all cases, the latter instances forming
a kind of transition to the receptacles of
special secretions, turpentine-reservoirs &c.,
found in the interior of the stems of many
plants. Glands may be conveniently divided
into external and internal : the former are
sessile, or stalked (when thsy present the
character of grandular hairs., of variou,-;
forms) ; while the latter are generally visible
externally as transparent dots scattered
over an organ, such as a leaf, giving it the
appearance of having been pricked all over
with a pin ; when of more considerable
dimensions, and with thicker walls, they
produce tuberculation of the surface, as on
the rind of the orange, &c.

E.rternalylands. These may besubdivided
into simple and compound.

Simple e.vternal (/lands are either sessile
vesicles or hairs, composed of a single vesi-
cular or elongated epidermal cell filled with
secretion; or they are hairs composed of a
simple row of cells, one or more of which
are filled with secretion. Examples of this
may be found in the epidermis of Priinida
sinensis, Gilia tricolor, Erodiiun cicviarinm,
Achimenes (Bl. 28. fig. ,32), Stachys, Marru-
hium, Digitalis jmrjnirea (fig. 33), Antir-
rhinum omijus (fig. 34), (Enothcra, llcUe-
bor us fat id us, Scropliularia nodosa (fig. 41),
Sempervivum, Salvia, Thymus, Mellissa,
Me.<icmb-yanthemum, Garden Chrysanthe-
mum (fig. 30), &c.

The slings of the nettles ai-e to be placed
here; they consist of very long, tapering,
single hairs, with an obtuse point, and a
bulb-like expansion at the base, imbedded
in a dense layer of epidermal tissue (1*1. 28.
fio-. 8). The hair is filled with the poisonous
secretion. When the point touches tlie
skin, it breaks ofi" and allows the escape of

the fluid contents, which are squeezed out
by the pressure, and probably by the tension
of the tissue around the bulb.

Compound external glands difier from the
simple only in the fact that they are coin-
posed of a greater or a smaller number of
cells combined into a mass, usually of sphe-
rical or allied form. They may be sessile,
or stalked upon a simple or compound hair.
Examples of sessile form occur in Dictamnus
albiis (PI. 28. figs. 38, 30), Rohinia viscosa,
the leaf of the mulberry and the Hop
(fig. 14), and the stipular glands of Cin-
chona, Galium, &c. ; of the stalked, in the
Rose (fig. 46), species of Huhiis, Drosera,
and on many aromatic or viscid plants.

Internal glands. These consist of cavities
in the subepidermal tissue, of variable size,
bounded by a firm layer of cells, and filled
with oily or resinous secretions. They ap-
pear to be formed either of one cell, when
small, or, when large, of a definite mass of
cells, which, after the production of the
secretion, have their Avails obliterated so as
to form a large chamber ; possibly, however,
some may be intercellular spaces into which
the secretion is poured out. Examples of
moderate dimensions are found in the leaves
of Dictainnus, 3Iagnolia (PI. 28. fig. 12),
Hypericum perforatum, and other species,
Myrtacece, Puta graveolens (fig. 11), &c.
Very large glands of this kind contain the
oil in the rind of the orange (fig. 280) and
other species of Citrus.

Fig. 280.

0 "-(^

Section of the rind of an orange, showing the internal
glands, R, R.

Magn. 50 diams.

The nectaries of flowers have their tissue
metamorphosed into a condition resembling
that of the secreting part of glands ; and
the hairs of the stigma of Flowering Plants
produce a secretion at the period of impreg-
nation. Brongniart has lately pointed out
the existence of internal glands in the dis-
sepiments of the ovaries of the petaloid
Monocotyledons. These structures form a
transition to the turpentine-canals &c. of
the Conifer;©. (See Secreting organs
of I'lants.) The Gummi-Keiden of Meyen

GLANDULINA.

[

GLEXOPIIORA.

(ci/stoh'flis of "VVeddpll) are also related to
glands. (See Raphidf.s.)

Bennett draws attention to certain glands,
imbedded in the leaves of Droseiut, I'inyui-
ciila, and Callifriche, at first sight resem-
bling stomata, with two papilla?. They are
supposed to be related to a carnivorous func-
tion. Similar structures seem to exist in
leaves of the garden rhubarb (PI. 2. fig. 14).
BiBL. Meyen, Secretionsorg. d. Pflanzen.
Berlin, 1837 ; Brongniart, Ann. Sc. Nat.
4 st5r. ii. 5 ; Lawson, A7m. N, H. 2 ser. xiv.
IGl ; Trecul, Ann. Sc. Nat. 4 s(?r. iii. 303 ;
Ann. N. H. 2 ser. xvi. 146 : Tieghem, Ann.
Sc. Nat. 1872 ; Sachs, But. 92 ; Bennett, M.
M. Jn. 1870, XV. 1.

GI.ANDULI'XA, D'Orb.— A Nodosa-
rian Foraminifer. It has a free, regular,
straight, ovoidal shell ; globular, almost com-
pletely embracing chambers, the last being
convex and prolonged ; and a round, minute,
terminal orifice.

G. IcBviyata (PI. 23. fig. 28). Eecent and
fossil. Common in the Lias and Chalk.

BiBL. D'Orbigny, For. Foss. Vien. 28;
Morris, Br. Foss. 36; Parker and Jones,
Ann. N. H. 2 ser. xix. 280.

GLAUCO'MA, Ehr.— A genus of Infu-
soria, of the family Trachelina, E.

C/iar. Body ciliated all over; mouth
longitudinal, oval, without teeth, placed
laterally near the anterior third or fourth
of the body, and furnished with one or two
tremulous laminiB or lips.

Stein describes the encysting process as
occurring in one species.

G. scintiUans, E. (PI. 31. fig. 8). Body
colom'less, slightly depressed, elliptical or
ovate ; sacculi large; length 1-290". Fresh-
water, and in infusions (of hay, &c.).

G. viridis, D. Body gi-een, oval ; mouth
large, nearer the middle than the anterior
end of the body; length 1-630". In pu-
trid rain-water collected in an empty wine-
cask coated with cream of tartar.

BiBL. Ehrenb. Infus. 334 ; Dujardin,
Infiis. 475 ; Stein, Infus. 250.

GLEICHENIA'CE^. — An order of
Ferns, distinguished by the soriof few (2-10)
obliquely annulated sporangia, -which open
vertically (fig. 2^2). Genera :

Gleichenia. Sporangia collected in round-
ish sori. Indusium absent. Leaves forking.
Exotic (figs. 281 & 282).

Platyzoma. Sporanges collected in point-
like sori. Indusium spurious, formed by the
revolute margin of the leaf. Leaves undi-
vided.

Fig. 281.

Fig. 282.

Gleichenia.

Fig. 281. Fertile pinnules with sori. Magn. 5 diams.

Fig. 282. Sorus composed of four crucially arranged

capsules. Maga. 40 diams.

GLEXODIN'IUM, Ehr.— A genus of
Infusoria, of the family Peridinfea.

Char. Carapace membranous, rounded
or oblong, with one or more distinct furrows
furnished with vibratile cilia ; an elongated
or horse-shoe-shaped red (eye-) spot pre-
sent ; no horn-like processes.

These organisms are doubtful Infusoria.
They are common in pools and bog-water.

&'. cinctum (PI. 31. fig. 10 a, b). Ovate
or subglobose, ends obtuse, yellow; cara-
pace smooth ; eye-spot large, transverse and
semilunar ; length 1-576",

G. apicidatum (PI. 31. fig. 10 c). Oval,
ends obtuse, greenish yellow ; carapace
smooth ; eye-spot oblong ; length 1-480".

G. tabulatum. Oval, greenish yellow ;
carapace granular, reticulated with promi-
nent lines ; ends acute or denticulate ; eye-
spot oblong; length 1-480"..

BiBL. Ehrenberg, Inf. 257; Dujardin,
Inf. 373 ; Kent, Inf 446.

"GLENOM'ORUM, Ehr.— The Glenomo-
)'um ttngens of Ehrenberg (PI. 31. fig. 14),
which consists of aggregated revolving
groups of green bodies, with two anterior
cilia, and a red (eye-) spot, has been shown
by Weise and Stein to form the young state
of Chlorogonium, which itself appears
probably to be a stage of development of
Pbotococcus.

GLENOPITORA, Ehr.— A genus of
Rotatoria, of the family Ichthydina.

Char. Free ; eyes two, frontal ; rotatory
organ circular and frontal ; tail truncated,
without toes,

G. trochus (PI. 43, fig. 36). Body ovato-

GLENOSPORA.

[ 358 ]

GLCEOCOCCUS.

conical, colourless, the turgid front and the
narruwed foot truncated ; eyes blackish ;
length 1-57U" ; IVeshwater.

BiBL. Ehreub. Inftis. p. 391.

GLEN0S'P01?A, Berk. & Desm.— A
genus of Uematiei (?) (Hyphomycetous
Fungi), of which one species (G. Thtoaitesii)
appears to have been fou)id in Britain.

Blbl. Berk. Hort. Journ. iv. p. 2o(J.

GLOBIGERI'NA, D'Orb. — A typical
Foraniiuifer. The shell is minute and glo-
bose, consisting of a series of ten or fewer
globular chambers, arranged spirally in two
or tlnee whoils, and increasing rapidly from
l-iiOOO to 1-80" in diameter. Surface
foraminated and rugose, sometimes prickly.
Each chamber opens into the umbilical
hollow by a crescentic orifice. In G. cre-
taeca and G. hirsuta the shell is almost dis-
coidal and nautiloid ; in G. hulloides (PL 24.
iigs. 2, 3) the chambers become heaped; in
G. helicina the later chambers expand and
grow irregular. In some cases the last
chamber overlaps all the others, and the
shell becomes an Orhulina.

G. buUoides is very abundant in the
Atlantic and other oceans, also in the
shallow water of the Adriatic. Many
varieties occur, recent and fossil, from the
Triassic period to the present day.

BiBL. Wallich, Biolog. Glohiy. 1876; Car-
penter, For. l8l ; Parker and Jcnes, Phil.
Tr. IBGo, 36o ; Bradv, Mic. Jn. 1879, 70.

GLOBULIN A, Turp. = GL(EOCAPSA.

GLOBULI'NA, DOrb. See Polymor-

PHINA.

GLCEOCAP'SA, Kiitz.— A genus of Pal-
mellacea3 (Confervoid Algae), distinguished
by the rounded cells, single or grouped into
families, with special and general lamellar
envelopes. As we have adopted it, it is
distinguished from Palmella by the persis-
tence of the coats of the parent-cells as
envelopes enclosing their progeny of several
generations, to the number of 4, 16, 64, or
more secondary cells, the membranes becom-
ing confluent subsequently, however, by
solution, into a gelatinous mass. From
Cvccoc/ihins the chief distinction seems to
be in the persistence of the lamellte of the
parent cells in the membranous condition,
and the globular instead of cylindrical or
ellipticnl form of the cells, while the habit
is to form rather fiat irregular strata tlian
globose or papillose masses. From Proto-
cocvus it is distinguished by the persistent
gelatinous investment. Some recent writers,
especially Sachs, assume that the species of

Gloeocapsa are early stages of development
of Lichens, from gonidia.

G. conjluens. Stratum gelatinous, green.
Diam. of cell-contents, 1-1200 to 1-600'".=
lite mat Qcocciis minutissimus, Hassall ?

G. montana. Stratum gelatinous, green ;
vesicles concentrically striated; cell-contents
1-1000 to 1-500'" in diam. = if. microsjiurus,
Hass.

G. (jranosa. Stratum green, firm ; vesi-
cles concentrically striated ; cell-contents
1-300'" in diam. = 7/^. c/trmosus, Hass.

G. j)ol)jdcrmatica (PI. 7. fig. 4 ). Stratum
hardish, olivaceous, somewhat compact or
granular ; concentric lamellse evident,
thick ; cell-contents 1-800 to l-oOO'" in
diam. = ^. rnpestris, Hass.

G. (TTuginosa. Stratum grey-feruginous,
granular-crustaceous ; vesicles large (1-100
to 1-60'"), irregular; cell-eoiitents 1-1000
to 1-600'".=^. ceruyinosus, Hass.

G. lividia. Stratum dirty olive or black-
ish, soft, but tubercular ; ceU-contents seru-
ginous ; 1-700'". H. lividits, iiaas.

G. Mac/ma. Stratum purplish-blaclc,
criistaceous, granular; cell-contents 1-600
to 1-320'". tSorosjiora montana, Hass.

G. sanc/iiinca. Stratum black ; internal
cells deep blood-red ; ceU-contents 1-000 to
1-400'". = Ilcematococcus sanyuineus, Ag.,
Hass.

G. Shuttleu'ort/iiana. Stratum dirty red ;
internal cells orange ; ceU-contents 1-1000
to 1-900'".

G. Balfsiana. Stratum dirty purple ;
internal cells rosy-purple ; cell-contents
l-7oO to 1-^00'" . = Surospora Palfsii, Hass.

In PI. 7. fig. 13 is represented a form we
have met with among freshwater Algas,
which appears to agree with Kiitzing's
G. ampla.

Those resting forms of Euylena where the
encj'sted groups are devoid of a firm outer
coat, bear considerable resemblance to a
large Gloeocapsa.

Babenhorst describes 55 European species.

BiBL. Kiitzing, Pht/c. (/en. 173, Sp. Alt).
216, 7rti. Phyc. pis. VSetseq.; Hassall, ^/y,^<^,
pi. 79, &c. ; Sachs, But. Zeit. xiii. 1 ; Al.
Braun, Bejuv. (Bay Soc. 1853), 131, 182;
Rabenhorst, Fl. Ak/. ii. 34.

GLQ^OCOC'CUS, Braun.— A genus of
Palmellaceoe, consisting of active liiciliated
gonidia resembling the moving form of
Protococcus, but connected into families by
a mass of soft jelly. See Palmellace^b.

BiBL,. A. Jkaun, 7Vr/yV«//i<?;/7, 169: CJiy-
tridien, 57; Rabenhorst, Fl. Aly. iii, 36 (fig).

v

GL(EOCYSTIS.

[ 359 ]

GXETACE.'E.

GE(EO0YS'TIS, Niiu-cli^ Ghvocapm, pt.

GL(E().SPO'lUUM,xSlc)utagiu>.— Ageiuis
of Sphaeroiiemei (Stylosporous Fungi),
developed Ijeiieatli (lie .surfixve of leaves, and
biav-ting through, fi)riuiug-a kiud of rust on
the surface.

G. paradoxum (HTi/.vos2)orium paradoxum,
De Notar.) occurs on ivv.

O. Lnhes. Asteroma Labes, Berk. Brit.
Fiiiiyi.

G. concentricum (^CyUndrosporum concen-
tn'ci/m, Grev. Se. Cn/pf. Flor. p. 27) forms
a ■while rust upon cabbage-leaves.

BiBL. Berk. & Br. Ann. Nat. Hid. 2 ser.
V. p. 4.5-) ; Berkelev, Ilort. Trans, vi. p. 121.

GL(EOTIIE'CA, Nag.— A genus of
Pahnellaeea} (Confervoid Algiie), distin-
g-uished by the obloug or cylindrical cells,
with thick, often lamellar envelopes.

13 species ; on humid rocks (Rabenhorst,
Fl. Ah/, ii. 60).

GLCEO'TILA, Kiitz.— A genus of Con-
fervaceje with simple, submoniliform fila-
ments, endochrome of the cells becoming
contracted and rounded. Ten species.
Freshwater ; in ditches and aquaria. (Ra-
benhorst, Fl. Ah/, iii. 319.)

GLOIOSIPH'O'NIA, Carm.— a genus of
Cryptonemiacene (Florideous Algse), the
single British representative of which is a
rare, feathery, red sea- weed, .3-12 inches
high, with a semigelatinous tubular frond.
The spores are in dense masses, scattered
among the radiating j i linted filaments which
clothe the periphery of the branches.

BiBL. Harvev, Mar. Aly. 152, pi. 21 A,
Eny. Bot. pi. 1219.

GLYCERINE is the sweet principle of
fats. It may be prepared by boiling fats
with oxide of lead and water. The aqueous
solutions are freed from the lead by sulphu-
retted hydrogen, the filtered liquid eva-
porated to the consistence of a syrup, and
finally in vacuo over sulphuric acid. It is
now procured by decomposing the fats with
high-pressure steam.

Glycerine, when pure, is a colourless,
highly refractive, syrupy liquid, of a sweet
taste ; it mixes in all proportions with alco-
hol and water, but it is insoluble in ether.
The property possessed by glycerine, of
constituting a liquid which does not become
dry, and mixes with water, renders it very
useful for the preservation of microscopic
objects; especially those which will not
permit of being dried, such as preparations
of vegetable structure, which may be left on
a slide in a di'op of glycerine, with a glass

cover to exclude dust, forweelcs and months
without alteration. It renders objects very
transparent, which is sometimes advan-
tageous, sometimes the reverse. A solution
of gum-arabic in diluted glycerine is often
used for mounting objects which do not bear
drying. The solution is made by dissolving
1 oz. of very clear gum in 1 oz. of water, and
adding subsequently 1 oz. of glycerine:
great care must be taken, in incorporating
the glycerine, to avoid forming air-bubbles,
which are difficult to get rid of on account
of the viscidity of the fluid. The mode of
mounting objects is to soak them in pure
glycerine, and then to operate as with
Canada balsam, only not applying heat.
GLYCIPH'AGUS^Hering.— Asubgenus

of ACARUS, p. 8.

GL Y'PHIS, Ach. — A genus of Graphidei
(Lichenaceous Lichens).

G. labi/rinthica, on trees, very rare,
(Leighton, Lich.-Flara, 436.)

GLYPllODES'MIS, Grev.— A genus of
Diatomacese.

Chnr. Fr. united into a filament; side view
naviculoid, with a central nodule, median
line, and transverse rows of granules; struc-
ture clathrate (?), the granules being deve-
loped within square areohe, arranged in
parallel rows.

G. eximia. In scrapings of marine shells.
Jamaica.

BiBL. Greville, Qu. Mic. Jn. 1862, 234
(figs.).

GLYPHODIS'CUS, Grev
Diatomaceee.

Char. Fr. four-sided, the angles much
rounded. Valves with a large 4-angled
nucleus, the angles alternating with those
of the margin ; and a circular prominent
process within each marginal angle, from
which costse radiate to the nucleus ; while
similar costae radiate from the angles of the
nucleus to the sides of the disk.

G. stellatus. Monterey stone.

BiBL. Greville, Mic. Tr. 1862, 91.

GLYPHOMIT'RIUM, Bridel.— A genus
of Orthotrichaceous Mosses, deriving its
name from the gi'ooved calyptra. Gh/pho-
mitriiDu Daviesii, Brid., is found in Wales
and Ireland on rocks, mostly near the sea.
It is peculiar to Great Britain and Ire-
land.

GNAT. See Culex and Culicid.^.

GNETA'CE^E.— An order of Flowering

Plants, remarkable for their jointed stems,

composed of ducts and wood-cells marked

like the wood of Conifers. The rind and

A genus of

go:mpitillus.

[ 360 ]

GONATOZYGOX.

Fig. 283.

Glyphomitrium Daviesii.
Teeth of the peristome. Magnified 150 diams.

pith, also, contain curious branched liber
cells.

GOMPHIL'LUS, Nyl.— A genus of
Lichenaoeous Lichens.

G. calycioidc'S. On mosses, rare. (Leigh-
ton, Lich.-Flora, 50.)

GOMPPIOGRAM'MA, Biauu.— A genus
of Diatomacese, cohort Fragilariese.

Char. Frustules solitary or geminate,
front view tabellar, -with interrupted clavate
longitudinal vittaB, ends internally dentate ;
valves ovate or elliptic-lanceolate, Avith
transverse continuous costte.

G. rivpestre (PI. 62. fig. 3). On moist
rocks (freshwater).

BiBi.. Pabenhorst, Fl. Air/, i. IIG; and
p. 12 (fig.).

GOMPHOXE'MA, Ag. — A genus of
Diatomacefe.

Char. Frustules mostly single or binate,
attached by a filiform stipes, vvedge-shaped
in front view ; valves with a median fine and
a nodule at the centre and at each end, and
striated with transverse or slightly radiating
granular strife. Freshwater and fossil.

Conjugation has been observed in several
species.

Kiitzing describes thirty-eight species;
Smith admits twelve as British. The form
of the frustule is subject to great variety ;
and the specific characters are probably of
little value.

The most common species are : —

G. acuminaf 1(771 (PI. 16. fig. 34 «, b, c).
Frustules in front view simply cuneate, or
inflated in the middle ; valves attenuated at
the base, ventricose in the middle, beyond
which they are again expanded ; ends acu-
minate, or truncate with an acuminate pro-
longation; sti-ife distinct; length of frustules
1-360". San Plore deposit.

G. (/emin(ifu77i. Valves ventricose in the
middle, constricted and rotundo-truncate
towai'ds each end ; stria3 distinct ; stalks

long, thick, densely intei-woven ; length of
frustules 1-216 to 1-180".

G. oUvaceimi . Densely crowded, forming
a mucous mass ; frustules broadlj^ cuneate
(fr. V.) ; valves obovato-lanceolate ; strife
distinct; length of frustules 1-1020''.

G. cu7-vatum. Frustules curved ; valves
obovato-lanceolate; striae faint; length
1-720".

BiBL. Ehr. Infus. 215 : Kiitzing, Bacill.
84,- and Sj). Alff. 6S; Smith, Br. Diatom.
76; Ealfs, Aim. N. H. 1843, xvi. 459.

G0:MPH0SPH^E'RIA, Ktz.— a genus
of Palmellacese ; with the cells radiating,
and united into groups in a globose mucous
envelope.

G. ajyonina. In pools. (Rabenhorst, Fl.
Al(f. ii. 55.)

GONATOBO'TEYS, Corda.— A genus of
Mucedines (Hyphomycetous Fungi), the f er-

Fig. 284.

Fig. 285.

Gonatobotrys simplex.

Fig. 284. A fertile filament. Magn. 100 diams.
Fig. 285. A sporiferous joint, with most of the
spores removed. Magn. 600 diams.

tile filaments of which present at intervals
swollen articulations, on which are attached
simple ovate spores (figs. 284, 285).

BiRL. Corda, Icones Fungo7-vm.

GONATOR'RHODON, Corda. — A
genus of Mucedines (Hyphomycetous
Fungi), the fertile filaments of which have
at intervals swollen artictdations, whence
arise moniliform chains of spores (fig. 286).

BiBL. Corda, P/'«c/<(^. eu7-op. Schiiimielb.
pi. 3.

GOXATOZY'GON, De Bary.— A genus
of Biatomacene.

Char. Cells cylindrical or truncate-fusi-
form, neitlier constricted nor incised, united

GONGROSIKA.

[ 3r,i ]

GONIUM.

into long fragile Fig. 286.

iilanionts; endo-
cliroiue simple, un-
dulate and twisted.
2 species ; fresli-
Avater.

G.Iialfsii (PI. ol.
fig. 37).*

BiBL. Raben-
hoi-st, Fior. Alff. iii.
p. 1.5.5.

GONGROSl'RA,
Ktz. — A genus of
C h ae t o p li or a c e 88
(Confer void Algas),

Gonatorrhodon speoiosum.

Fertile filaments with swollen joints bearing chains of
spores. Magn. 100 diams.

Filaments jointed, sub-diehotomously
branched or tufted, attenuated at the base to
form a root-like thread; joints as long or
twice as long as broad, toridose. Four
species ; minute ; on stones, wo ad, and
aquatic plants. (Rabenhorst, Fl. Alff. iii.
3«7.)

GONID'IA. — The name applied to cells
which in the Thallophytes perform an office
analogous to that of the Geisiji^ of the
higher Crj'ptogams, and theseparatiugbud-
structures such as bulbils, stolons, &c. of the
Flowering Plants, — being cells developed
from the vegetative tissues, ultimately
thrown off, and capable of propagating the
individual. The gonidia of the Lichens are
globular cells with green contents, developed
in the central layers of the thallus, afterwards
set free by the destruction of the cortical
layer; they appear capable of multiplication
by subdivision before growing out into the
filaments which form the foundation of the
new thallus (see Lichens). And the en-
dochrome has lately been observed in a few
Lichens to be resolved into zoospores, a cir-
cumstance which brings Lichens inan im-
portant point still nearer to Fungi. The
gonidia of the Fungi are usually termed
CoNiDiA (see that article, and FuxGi). The
gonidia of the Algse are best known in the
CoxFERVOiDS, where they are formed from
the cell-contents, and generally present
themselves ciliated, as Z^oospoees. The
tetraspores of the Floridete are probably
the homologues of gonidia.

GONIO'COTES, Nitz.— A subgenus of
Philopierus, like Goniodes, but the antennae
alike in both sexes.

G. hohyaster, on the fowl.

GONIOCYTRIS, B. & R.— A minute
Ostracode,with yellowish, compressed, trian-
gular valves ; found in the rivers and dykes
of Eastern England.

BiBL. Brady and- Robertson, ^?m. N. II.
1870, vi. 15.

GONIO'DES, Nitzsch.— A subgenus of
Philopterus (Anoplura), distinguished by
the large head, with projecting temporal
angles, no trabeculaj ; antennae forcipate in
the males, cylindrical in the females.
Several species, on the turkey, the guinea-
fowl, the domestic fowl, the pheasant, and
the grouse.

GONIOM'ONAS, St.— A genus of Fla-
gellate Infusoria.

Char. Free, or adherent posteriorly ;
flagella two, equal, obliquely truncate in
front.

G.truncata. Freshwater. (Kent,77?/.280.)

GONIONE'MA, NyL— A genus of Bya-
saceous Lichens.

G, velutimim. On subalpine rocks ; rare.
(Leightou, Lich. Fl. 9.)

GONIOTHE'OILM, Ehr.— A genus of
fossil Diatomacese.

Char. Frustules terete, with a median
(longitudinal) constriction (suddenly atte-
nuate and truncate at the ends, hence ap-
pearing angular).

Corresponds to Pt/xidicida, constricted in
the middle, and truncate at the ends.

Found in America.

We have figured several of the nine or
ten species, some of wdiich do not appear to
have the characters of the genus.

G. Annidus (PL 51. fig. 18) ; G. harhatum
(fig. 19) ; G. didymurn (fig. 20) ; G. mono-
don (fig. 21) ; G. naviciila (lig. 22) ; G.
Roqersii (fig. 23) ; G. qastridium (PI. 60.
fig.' 40) ; G. odontella (iig. 44).

BiBL. Ehrenberg, Ahh. Berl. Ak. 1841,
401, Berl. Ber. 1844, 82, and Mikroyeol. ;
Kiitzing, Bacill. 51, and aS^^. Aly. 23 ;
Greville, Mic. Tr. 18(35. 56.

GO'^'IUM, Miiller.— A genusof Volvo-
cinese (Confervoid Algaj), forming micro-
scopic, square, flat fronds, either cihated and
endowed with a power of motion, or devoid
of cUia and motionless ; it is possible that
these two conditions are only stages of deve-
lopment in species- active at one time and
resting at another. The perfect fronds are
composed of usually sixteen cells, enclosed
in wide coloiu-less coats (young fronds but
four cells, some kinds have more than six-
teen) united together into flat square masses
by adherence at various points of their cir-

GONOTHYR.EA.

[ 3G2 ]

GRAMMATOXEMA.

cumference. A light vacuole in the suh-
stance of the cell-contents may often he ob-
served to exhibit a rhythmical con*:raction
arid expansion, as in Vo/vo.r. The cells of
the active forms have each a pair of vibratile
cilia, which run out from the central proto-
plasmic mass, through the b^'aline envelope,
and project as free processes, rowing the
frond about in the water. They are com-
monly observed to increase by division, a
frond composed of sixteen cells breaking up
into four fronds, each composed of four cells,
&c. ; but it is probable that other kinds of
development exist, and that the motionless
forms are resting states of active species.
Gonium pectorale is an exceedingly interest-
ing microscopic object, not uncommon in
freshwater pools.

G.pedorale (PI. 7. tig. 11). Frond square,
composed of sixteen bright-green cell-
masses enclosed in hyaline envelopes, each
with a pair of cilia ; size of green masses
1-1960 to 1-1150"; frond not exceeding
1-280". In clear water, salt and fresh,
near the surface.

G.imncialum. Cells sixteen; cell-masses
green, with black granules ; diam. 1-4600" ;
frond of sixteen, 1-576".

G. tranqniUum (PI. 7. fig. 12). Cells
sixteen ; cell-masses green, diam. 1-2880" ;
frond of sixteen, 1-144 to 1-288", some-
times twice as broad as long ; the cell-masses
found in division (biuate or quaternate),
motionless. (Possibly not a Gonium, but a
Palniellacean — Tetraspora P).

G. hyalinum. Cell-masses hyaline, diam.
1-3000"; frond of twenty or twenty-five,
1-600". In stagnant water.

G. fjlaucmn. Cell-masses bluish gi'een,
from four to sixty-four in a frond, diam.
1-7000 to 1-4200"", ditto of frond not ex-
ceeding 1-570". In sea-water.

BiBL. Ehrenberg, Inf. 55 ; Cohn, Nova
Acta, xxiv. 109, pi. \^ ; Fresenius, Mtis.
Setickenh. Gesell. ii. 187, 1856.

GONOTIlYRyE'A, Alhnan.— A genus
of Oampanulariidse, Hydroid Zoophytes.
2 species.

G. Loveni (Laomedia dichotoma, John-
son), on the fronds of the large sea-weeds,
and on stones, at low-water mark.

BiRL. Hincks, Hydroid. Zooph. 180.

GOli'DlUS, Linii. — A genus of Nema-
toid Entozoa.

Char. Body veiy long and slender, fili-
form ; alimentary canal (none, Vill.) with a
single orifice, sexes distinct.

G. aquations, the common hair-worm, is

from 7 to 10" in length and about 1-25 to
1-20" in breadth, of a brown or blackish
colour, and is found in water or damp
places. The mouth is very indistinct ; the
tail of the male is bifid, that of the female
simple and rounded.

The ova, agglutinated in long strings, are
deposited in water, and being devoured by
insects or Arachnida, undergo development
within their bodies.

These animals frequently coil themselves
into a knot-like form, whence the name.

See Mermis.

BiBL. Dujardin, Helminth. 290, and Arm.
So. Nat. 1842, xviii. 142 ; Ent,. Zcit. 1842
-43, and Erichson's Archiv, 1843, ii. 302 ;
Berthold, Ban d. Wasserkulbes, 1842 ;
Meissuer, Sieh. Sf Koll. Zeits. 1856, i. ; Sie-
bold, ibid. 141 ; Grenadier, Sieh. S^- Koll.
Zeitsch. 1868 ; Villot, Ann. N. H. 1872, x.
231 ; Compt. Rend. 1880, 1569 ; Ann. N.H.
1880, vi. 160.

GORGO'NIA, Linn.^ — A genus of marine
Polypi, of the order Actinoida, and family
Gorgoniadffi.

Char. Polypidom rooted, and consisting
of a central, branched, horny, and sometimes
anastomosing flexible axis, coated with a
soft and fleshy pohqiiferous crust.

The species are popularly known as sea-
fans; they are not microscopic, often attain-
ing very considerable dimeui^ions.

The polypidom, as well as the crust, con-
tains spicula of .various forms imbedded in
them, a specimen of which is exhibited in
PL 41. fig. 27.

BiBL. Johnston, Brit. Zooph. 166 ; Kent
(spicules), M. M. Jn. 1870, 76 ; Gosse, Adi-
noloqia.

GOSSYPIUM. See Cotton.

GOUT-STONES. See Chalk-stones.

GRACILA'RIA, Grev.— A genus of
Rhodymeniaceae (Florideous Algae), with
feathery fleshy-cartilaginous fronds, 3 to
12" or more long, of a red or purplish colour,
the central substance of which is composed
of large cells, the cortical of closely packed
horizontal filaments. The spores are formed
in tubercles consisting of a thick coat com-
posed of radiating filaments, containing a
mass of minute spores on a central placenta.
The tetraspores are imbedded in the cells of
the surface. G. eonfervoides is the only
conmion species; it grows from 3 to 20"
long, and as thick as small twine.

BiBL. Ilarvev, Br.Mar.Aly. 128,pl.l6C;
Em/l. Bot.f\. 16(J8.

GRAMMATONEMA, Ag.— A genus of

GRAMMATOPIIORA.

L 303 ]

GRANTIA.

microscopic marine plants, by some referred
to the l>iiito!iuicea3, by others, including
Kalfs and Kiitzing, to the lJe.sni:diaceiie,

The recent observations of Smith show
that it belon<xs to the former family, and to
the genus Fnti/ilaria.

G. stri((tuluin = Fr. sfriatula.

GRAMMATOrii'OllA, Ehr.— A genus
of Uiatomacese.

Char. Frustules in front view rectangular,
at tirst aduate, but after^Yards forming zig-
zag chains ; vittix; two, longitudinal, inter-
rupted in the middle and more or less curved.
Marine.

Valves linear or elliptical ; furnished Avith
transverse stri;ie, in most, invisible by ordi-
nary illumination, and in a few so dithcult of
detection that the valves have been regarded
as Test Objects. Sometimes a median
and terminal nodules are present.

Rabenhorst describes eleven species. Four
are British ; one doubtful : —

G. marina (PL 1. fig.l4; PL 16. fig. 35).
The markings or strite are invisible by ordi-
nary illumination; vittte near the middle
semicircidarly cur\ed outwards ; valves
linear or elliptical, gradually attenuated
towards the obtuse ends ; striae transverse ;
length 1-108 to 1-240".

The form and structure of the frustules
and valves appear greatly to vary. Some-
times the frustules are perfectly square, at
others sis times as long as broad. In some
specimens the valves are suddenly, at others
uniformly inflated at the middle (PL 1.
fig. 14 h ; PL 10. fig. 35 c), some have the
ends capitate. Again, in some valves there
is a median line and a small central nodule
(PL 16. fig. 35 c) ; in others there is neither
median line nor nodule, but a large internal
ring (PL 1. fig. 14 b). Lastly, in some valves
the strife extend over the whole of the valves,
while in others they are deficient at their
ends. Some of these variations have formed
the ba^is of distinct species, but probably
with httle reason.

A variety, G. snbtilissima, Bail. (PL 1.
fig. 15 a, b), has been pointed out by Prof.
Bailey, in which the form of the frustules
and valves agrees with the above characters,
but in which the transverse striae are ex-
tremely difiicidt of detection when mounted
in balsam.

G. macilenta. Fr. slender, often curved ;
vittae as in the last ; valves linear, slightly
inflated at middle and ends. Marine ;
length 1-300".

6r. serpentina. Vittae long, serpentine, with

the end curved inwards to form a kind of
hook; stiiaj oblique. Marine; length 1-200".

G. ? Balfouriana. Vittie straiglit ; valves
linear, inflated in the middle, and with
rounded ends. Freshwater.

BiBL. Ehrenberg, Berl. Abh. 1839, 120,
and Ber. 1840, iV-c. ; Kiitzing, Sp. Ah/. 120;
Bailey, Sillivians Jount. vii. ; Smith, Br.
Diat. ii. 42 ; SchifF, Sckulfzc^s Archiv, iii,
81 ; Rabenhorst, Fl. AUj. i. 303 ; Petit, Jn.
Mic. Soc. 1881, i. 109.

GRAMMITID'E.-E.— A family of Poly-
podiaceous Ferns.

Char. Sori on the back of the fronds,
more than twice as long as broad, usually
linear. Genera :

Jamesonia. Sori oblong, on the flabellate
veins of the back of the pinna3, not reaching
the margin.

Brainea. Sori continuous along trans-
verse veins near the midrib, also produced
along the veins towards the edge of the
frond.

Notochlcena. Sori marginal, oblong or
rounded, then confluent into a marginal line,
the edge of the frond frequently iiiflexed to
form an involucre ; veins free.

Monogramma. Sori linear, close to the
midrib on one or botli sides.

Gymnogramma. Sori on the veins of the
under sm'face of the frond, linear, simple or
furked.

3Ieniscium. Sori oblong or linear, occu-
pying the conuivent transverse veinlets of
the simple or once pinnate fronds.

Antrophgnm. Sori on the veins, imper-
fectly reticulated.

Vittaria. Sori in continuous marginal or
slightl} intramarginal lines.

Tcenitis. Sori linear, the line sometimes
interrupted, central or submarginal.

Drgmoglossmn. Like Tanitis, bat the
fronds dimorphous.

Hemionitis. Sori continuous along the
veins, and copiously reticulated, sometimes
also slightly developed between them.

GRAMMFTIS, Swartz., is merged into
Pulypodium and Ggmw)gramma. C'eterach
is sometimes taken for a Grammitis.

GRAMMONE'MA, Ag. = Gbammato-

NEMA.

GRAN'TIA, Fleming. — A genus of
Sponges.

Char. Form variable; firmish and in-
elastic, usually white, with a close but po-
rous texture, and composed of a gelatinous
base, with imbedded calcareous spicula; ori-
fices distinct. Marine.

GKANULE-CELLS.

[ 364 ]

GEEGARINA.

Spicula simple, radiate or stellate, com-
posed of carbonate of lime ; hence easily
distinguished from the siliceous spicula of
other sponges h v their dissolving with effer-
vescence in a dilute acid. The organic basis
is stated not to be fibrous as in most other
sponges.

The British species are found growing
iipon or from rocks, sea-weeds, shell-fish
and j;oophytes, between tide-marks. They
vary in size from about the 1-10 to 3 or 4".
Gemmules have not been found.

BiBL. Johnston, Br. Sponr/es, 172; Grant,
Compar. Anat. and New Phil. Journ. i. and
ii. ; Bowerbank, Br. Sporuj. ii. 1.

GRANULE-CELLS.— This term has
been applied to cells found in animal solids
and liquids containing a number of globules
of fat or oil (PI. 38. hgs. 7, IG a, 17 e). They
are of variable size, perhaps the average
may be placed at 1-2000" ; and are easily
recognized by the dark margins and light
centres of the globules, which are insoluble
in acetic acid and solution of potash. The
cells sometimes contain a nucleus, at others
not. The term granule-cells should pro-
perly be limited to cells of new formation,
as those found in inflammation, cancer, &c.;
but it has been so generally applied to cells
of whatever kind, containing fatty globules,
that it has no pathological signihcation.

See Degexebation, Fatty, and Inflam-
mation.

GRANULOSE. See Staech.

GRAPE-FUNGUS. See Oidium.

GRAPHID'EI— AtribeofLichenaceous
Lichens, having a thin, crustaceous, scarcely
A'isible or subepidermal thallus, with lirel-
liue apothecia.

It includes the British genera : Af/yrium,
Arthonia, CJiiodecton, Gli/phis, Grap/iis,
.Lithoyraplin.1 Melaspilca, Ope(/ra]>ha^ Phtfy-
grapha, Plyclioyrapha, tSfiynmtidium, and
XyloyrapJia.

BiBL. Leighton, Brit. Lichen-Flora^ 390.

GRA'PHIS, Ach.--A genus of Graphi-
dei, containing ten British species, very va-
riable in their appearance ; mostly whitish
or yellow papery expansions on the bark of
trees, beset with irregular black markings
(lirelline apothecia) like writing.

BiBL. Leigliton, Brit. Lich.-Fl. 420.

GRASSES.— A family of Monocotyledo-
nous Flowering Plants, remarkable in many
respects for their microscopic structure,
especially the siliceous Epidermis and the
Starch grains in the Albumen, for which
see those heads.

GRATELOU'PIA, Ag.— A genus of
Cryptonemiaceae (Florideous Algse), repre-
sented by a very rare British species, G.Jili-
cina, seldom growing more tlian 2 inches
high with us. Fructiti cation minute, im-
mersed, faveUidia opening by a pore, and
cruciate, tetraspores vertically placed among
the filaments of the peripherv.

BiBL. Ilarv. Mar. Aly. 137, pi. 17 A;
Grev. Aly. Brit. pi. 16.
■ GREENS AND.— According to the ob-
servations of Ehrenberg and Bailey, the
glauconitic grains frequent in many geolo-
gical deposits, especially in certain beds
known as Greensaud, are formed of fossilized
organic bodies, mostly casts of Foramini-
fera.

BiBL. Ehrenbera:, Ahh. Berl. Akad. 1856,
85-176; Monatsber.l%o^,?>-2^; BnWej, Ann.
N. H. 8. 2. xviii. 425; Parker & Jones, ^;/;;.
N. H. s. 4. X. 263 ; SoUas, Geol. Mag. 1870,
53t».

GREGARI'NA, Dufour.— This curious
gi-oup of organisms, which was formerly
placed among the Entozoa, is now placed
among the Protozoa, forming the Order
Gregarinida ; but there are still doubts as
to their structure and nature.

They exist as parasites within the bodies
of animals, and often inhabit the intestinal
canal, or the cavity of the abdomen. Most
frequently they are met "with in insects,
especially their larvas ; but sometimes also
in Annelida, both freshwater and marine
(Lumbricus &c.), in the Crustacea and Mol-
lusca ; and even in human organs.

They are mostly microscopic, and colour-
less ; round, oval, fusiform, or cvlindrical
(PI. 21. figs. 25, 28, 34) ; and consist of a
smooth transparent cell-wall, enclosing a
gi'anular, more or less hquid mass, with one
or more nuclei or uucleoh. Sometimes
they exhibit a constriction in the middle,
or are divided by a transverse septum. In
some a process resembling a head is situated
at one end ; this may be short, round, and
obtuse or pointed, or more elongated and
furnished with reflexed hook-like processes.
The GreyarincB are capable of motion, which
is either that of slow progression, ensuing
without contraction of the body, or pro-
duced by irregular contraction of the mem-
brane or substance of the body.

Vibratile cilia have been detected both
upon the outer and tlie inner surface of the
membrane; and the internal granules often
exhibit molecular motion, especially after
the addition of water. One or more lono-

GRIFFITIISIA.

[ 3G5 ]

GRIMMIA.

motionless filaments sometimes arise from
the outer surface.

Tlie membrane and its contents, except
the nucleus, are soluble in acetic acid.

Their method of propagation, if such it
is, represents a form of conjugation, and
takes place as follows. Two indivitluals
coming into contact bj corresponding por-
tions of the body (PL 21. fig. 34), become
shortened and firmly united. A transparent
capsule is next formed around them, which
encloses them in a cyst (tigs. 20, 30), the
adjacent portions of the cell-membranes are
absorbed, and the substance of the two
bodies become intimately fused. Globules
or cells are then formed in the contents of
the cell, which subsequently assimie the
form of XavicuUe, and have been called
pseudo-navicuhx? (erroneously navicellce :
figs. 31, 32, 33); these burst, producing
Amcebifoi'm bodies, which develop into new
Gre(/ari)ue.

It was supposed that the pseudo-naviculae
were really Xavicidcp, and that the cysts con-
taining them were sporangia ; but the pseu-
do-naviculse do not possess a coat of silex.

In some cases it appears that the con-
tents of the two cells in conjugation remain
distinct until the pseudo-naviculse are
formed ; but it is not certain whether each
single cell in these instances has not arisen
from the fusion of two others.

A very large number of species of Gre-
garina have been described and arranged in
numerous genera.

BiBL. IXifom', Ann. Sc. Nat. 1837, vii. ;
Stein, Miiller's Arch. 1848 ; Ann. N. H.
1850, v.. and Infus. ; Frantzius, Greqar.
1846; Henle, Midler's ArcMv, 183o, 1845 ;
Siebold, Natwff. d. ivirhdlos. Thure, 1830 ;
Kolliker, Sieh. ^- Kollikers ZeiUchr. 1848
& 1849 ; Ray Lankester, Qu, Mic. Jn.
1863, iii. 83, and l/^c. Tr. 1866, 23 (PL);
Y. Beneden {G. of lobster), Bull. V Acad. d.
la Belqique, 1869 {M. M. J. 1870, 47), and
Ami. X. H. 1872, x. 309.

GRIFFITH'SIA, Ag.— A genus of Cera-
miacese (Florideous Algge), with feathery
fronds 3 to 6" long, composed of delicate
dichotomously-branched tilaments consist-
ing of a single row of cells, the branchlets
often whoried ; colour crimson or rosy-red.
The fructification consists of spores, anfhe-
ridia, and tetraspores, all produced in simi-
lar situations, namely at the articulations,
where they are surrounded by a kind of
involucre formed of short ramelli, to which
the tetraspores and antheridia are attached.

The antheridia consist of a kind of shrubby
tuft of extremely minute iilaments arising
from an axial filament which arises from a
ramellus of the involucre. Fig. 287 repre-
sents a branch terminating in an involucre
of whoried ramelli bearing tetraspores ; the
lower figure is a portion of a ramellus

Fig. 287.

Grifflthsia sijhaerica.

Fig. 287. Fragment of a frond bearing an involucre with
tetraspores. Magn. 50 diams.

Detached ramellus of the inTolucre, showing the at-
tachment of the tetrasfiores. Magn. 40 diams.

showing the mode of attachment of the te-
traspores. In the antheridial involucres, the
plumose antheridial structure is attached in
exactly the same way. Seven British spe-
cies are recorded, of which one or two are
not uncommon.

BiBL. Harvey, Mar. Ah/. 167, pi. 23 B ;
Decaisne, Ann. Sc. Nat. 2 ser. x\ii. p. 353,
pi. 16 ; Thuret, Ami. Sc. Nat. 3rd ser. xvi.
16, pi. 5 ; Derbes and Solier, ibid. xiv. 276,
pi. 36 ; Migl. Bot. pi. 1479 & 1689.

GRIM'MIA, Ehrhart.— A. genus of Or-
thotrichaceous Mosses, containing numerous
British species.

Fig. 288.

Grimmia.
Teeth of peristome. Magnified 150 diameters.

Many of the species of Trichostomum of

GROMIA.

]

GUTTA-PERCHA.

Hedwig and Scliwaegviclien are placed here
by Bruch and Schimper and C. Miiller.

BiBL. Wilson, Bryol. Brit. 152 ; Berke-
ley, Handh. 287.

CtRO'MIA, Duj. — A genus of Rhizopoda,
of tlie order Reticiilaria.

(Jlnir. Carapace brownish yellow, mem-
branous, soft, globular or oval, with a small
round orihce, from which very long, fili-
form branched expansions with vei'y deli-
cate extremities protrude ; the presence of
a nucleus and contractile vesicle is doubtful,
or variable.

G. oviformis. Carapace globular, with a
short neck; marine; size 1-25 to 1-12";
among marine plants.

G.fuviutilis (PI. 31. fig. 15). Carapace
globular or ovoid, without a neck ; fre.<h-
water; breadth 1-280 to 1-100". Found
upon Ceratophylluni.

Schlumberger describes a freshwater
Gromin (liydUnd), differing from the last in
size (l-SGO to 1-520''), and in the carapace
being colourless, perhaps the young state of
G.Jltiviatilis. Schultze desci'ibes some new
marine species : G. oviformis, G. Dnjar-
dinii, and G.paludosa; G. terricola (Leidy)
is cream-coloured, and occurs in earth be-
tween paving-stones. "

BiBL. Dujardin, Ann. 8c. Nat. 1835,
iv., Infus. p. 252 ; Schlumberger, Ann. Sc.
JVat. 1845, iii. 255 ; Schultze, Polyihal. 55;
Cienkowski, Schultze's Arch. 1876, xii. 32 ;
Claparede and Lachm. Inf. 465 ; Leidy,
Sill. Am. Jn. 1875 (M. M.'Jn. xiii. 87).

GROWING-SLIDE.— Several modifi-
cations of this apparatus (Infrod. p. xxiii)
have been recently described.

See Smith, Ann. N. II. 1865, xvii. 334 ;
Barker, Qu. M. Jn. 1866, 267; R. Beck,
Mic. Tr. 1866, 34; Miiller, M. M. Jn. i.
1869, 174 ; Maddox, M. M. Jn. 1870, iii.
14; Broeck, M. M. Jn. 1876, xv. 221;
Lewis and Cunningham, ibid. 198 ; Jn. Mic.
Soc. 1880, 333 ; Beale, How 8fc. 76 ; Bot-
terill, Jn. Mic. Soc. xix. 34 ; Dalliuger,
M. Mic. Jn. 1874, xi. 97.

GUANO. — As is well Inunvn, guano is
imported into this country in large qu;inti-
ties as a manm-e. It consists principally of
the excrement of birds, in a more or less
decomposed state. It affords the micro-
scopist a means of procuring many foreign
marine Diatomaceaj, the frustules and valves
of which are often contained in it in large
numbers. The ] )ialomace,-r' nuiy be obtained
from guano as recommended at page 250.

GUEMBE'LIA, limp.— A genus of Or-

thotrichaceous Mosses, including various
species separated from Grimmin on account
of the peculiar calyptra, also the Cinclidoti
of P. Beauvais.

G. orbicularis, Hmpe. = (?m«mja orbicu-
laris, Br. Eur.

G. riparia=Cinclidotits riparius, Wils.

Fig. 289.

Fiff. 290.

Fig. 291.

Guembelia fontinaloides.

Fig. 289. A fertile shoot.

Fig. 290. Capsule with ealypti-a. Magn. 10 diams.

Fijj. 291. Teeth from the peristome. Magn. 1.50 diams.

G. fontinaloides (tigs. 289-91)= 0';(c/.
fontinaloides, P. B.

BiBL. Wilson, Bryol. Brit. p. L39.

GUM. — A name applied to various viscid
(not oily) secretions of plants. Gums have
no microscopic structure when pure and
clean, but often exhibit under the micro-
scope traces of structures, such as d6bris of
cellular tissue, filamentous Fungi, i*cc.,
which have become imbedded in them
while soft. What is called gum Trnga-
canth consists of partly decomposed cell-
membranes, in a condition allied to amy-
loid, retaining traces of their organizatiim.
Sections of very soft tissues or very minute
objects may be made hy imbuing them with
or immersing them in solution of gum, and
allowing the whole to dry up to a tough,
semisolid mass, capable of being sliced with
a razor. The slices are freed from gum by
soaking in water. Gum dissolved in Gly-
ckhink forms an excellent medium for
mounting vegetable tissues.

GUTTA-PERCHA.— A substance pro-
duced by the evaporation of the milky juice
of the Isonandra gutta, of the Natural
Order Sa]>i>tnceie, a native of Suuialra
and tlie neighbouring regions. Its relatinn
to the microscope arises from its use in a

GUTTULINA.

[ 367 ]

GYRINUS.

solid form and as cement, in mounting
microscopic objects in cells. See Cements
and Prepauation.

GUTTULINA. See Polymobphina.

GY'GES, Boiy.— Described by Ehren-
bfrg as a genus of Volvocinete, having
neither eye-spot, tail, nor iiagelliform iila-
ment ; the carapace (cell-membrane) simple,
subglobose ; freshwater.

Motion very slow. lie gives two spe-
cies :

G. granuhmi (PI. 50. fig. 14). Ovate or
subglobose; internal granular mass dark
green ; diam. 1-11-50".

G. bipartitm. Nearly spherical ; internal
mass yellowish green, frequently bipartite ;
diam.' 1-480".

So far as appears from the descriptions
and figures, these do not seem to diifer
from Protococcus.

(For G. sanyuinea^ Shuttleworth, see
Red Sxow.)

BiBL. Ehr. I/) fits. p. 61.

GYMNOAS'CUS, Bar.— A very minute
and simple form of Ascomycetous Fungi ;
found on horse- and sheep's dung. (Bara-
netzki, Bot. Zeit. 1872 ; Sachs, Bot. 310 ;
Eidam, Cohti's Beit. iii. 267 ; Jn. Mic. Soc.
1881, 489). See Ascomtces.

GYMNODINTUM, Stein.— A genus of
Cilio-flageUate l\ii\xsox\?i^=Periclinia with-
out a lorica.

7 species ; in fresh and salt-water (Kent,
Infus. 442).

"G YMNOGON 'GRUS, Mart.— A genus of
Cryptonemiacefe (Florideous Algae), with
horny branched fronds, the divisions cylin-
drical or compressed, a few inches high, of
a purphsh-red colom-. The substance of the
branches presents three layers of closely
packed filamentous cells, the central lon-
gitudinal, the intermediate curved, and the
peripherical horizontal and moniliform.
The spores have not been observed; the
tetraspores (cruciate) are arranged in mo-
niliform rows, in wart-like thickenings of
the branches.

BiBL. Harvev, Mar. AUj. 145, pi. 18 B;
Enql. Bot. pi. 1089 & 1926.

GYMNOGRAMMA, Desv.— A genus
of Grammitidete (Polypodiaceous Ferns),
some of the species of which are remarkable
for a yellow or white pulverulent appear-
ance on the back of the fronds, owing to
the presence of abundance of microscopic
cellular hairs, ex. gr. G. Calomelanos, G.
cfiry-^opht/lla, ochracea, &c. Many species,
mostly tropical. (Hooker, Syn. Fil. 376.)

GYMNOMIT'RIUM, Oorda.— A genus
of Jungermanniese (Ilepaticae), containing
one Britisli alpine species, the Jtinyennati-
nia co)ici)Uiaf(i of the British I'lora.

BiBL. Hook. Brit. Juny. pi. 3; Ekart,
Si)n. Juny. pi. 8. fig. 63 : Enql. Bot. pi,
1022.

GYM'NOPHRYS, Cienk.— A genus of
Reticularian Rhizopoda.

(Jhar. Body naked, wdthout nucleus or
contractile vesicles. The pseudopodial re-
ticulations, which exhibit the granular
currents, arise from a few variable points of
the surface.

G. cometa. In marine and boggy pools,
among algns. (Cienkowski, Schultze's Arch.
1876, xii. 31.)

G YMNOSPER'MIA.— A division of the
Flowering Plants (see Vegetable King-
dom), including the Coniferje and Cyca-
dace^ ; deriving this name from the mode
of development of the Ovl'les.

GYMNOSPORAN'GIUM, B.C.— A ge-
nus of Uredinei (Hypodermous Fungi). G.
juniperininn grows upon living branches
of the common Juniper, appearing at first
like an exanthema on the bark, which in wet
weather swells up into an orange-coloured,
tremelloid plicate mass, Avhich readily dries
up, however, and then is scarcely visible.
Somewhat rare, but when present generally
copious.

BiBL. Berk. Br. Fl. vi. part 2. 361 ;
Fries, Syst. Myc. iii. 505 ; Tidasne, Ann.
Sc. Nat. 4 ser. 'ii. 171 & 188.

GYMNOSPO'RIUM, Corda.— A genus
ofToridacei (Coniomycetous Fungi), cha-
racterized by an obscure mycelium and
unicellular black spores arising apparently
from the matrix. It is the lowest condi-
tion of which Torulacei are capable.

G. arundinis occurs in this country on
reeds.

BiBL. Corda,. Anleituny. 10: Berk. Oiitl.
32*^

GYMNOS'TOMUM, Schwagr.— A ge-
nus of Mosses now distributed into Py-
eamidium, Physcomiteium, and other
genera.

BiBL. MiiUer, Syn. Mtisc. ; Bruch and
Schimper, Bryol. Eur. ; Wilson, Bryol. Br.
39 ; Berkeley, Handh. 237.

GYPSI'NA, Carter. See Tinoporus.
GYRI'NUS, Geoffr.— A genus of Coleo-
pterous insects, of the family Gyrinidas.

G. natator, one of the eight British spe-
cies of this genus, is very commonly seen in
groups performing its gyrations upon the

GYRIXUS.

[ 368 J

GYROSIGMA.

surface of pools or rivers, whence it has
received the popular name of whirligig.

The body is ovate or elliptic, and de-
pressed, the elj-tra black and shining. The
antennae are short and retractile within a
cavity in front of the eyes; the basal joint
minute ; the second large, globular, and fur-
nished externally with an ear-like joint
fringed with coloui'less, flattened, hair-hke
processes ; the remaining seven j oints form
a clavate mass, being very short and closely
united, the first commencing by a very
narrow base or pedicle. The eyes are di-
vided by a transverse septum into two parts,
the upper of which serves for viewing ob-
jects in the air, the latter those in water ;
by some authors these insects are described
as possessing fom- distinct eyes. The tei'-
minal segment of the abdomen is fm-nished
with two retractile ciliated lobes. The two
fore legs are long, and of the ordinary form,
whilst the four hind legs (PI. 34. fig. 5),
wliich are used as oars, are short, flat, and
dilated; the femur (d) and tibia {c) some-
what triangular, the tibia also fringed with
short spines and long flattened filaments ;
in the middle pair of legs the latter exist
on both margins, whilst in the hind legs
these are present only on the outer mar-
gin. The tarsi (a) are five-jointed, the
three basal joints produced on the inside
into long, flat, leaf-like lobes fringed with
spines ; the fourth joint is of about the same
size, and semicircular, the fifth being very
short and attached to the fourth near the
end, and both are fringed on their outer
margin with flattened filaments resembling
those upon the tibia ; all the tarsi are fur-
nished with two distinct claws.

The anteriol- tarsi of the male differ from
those of the female, as in Di/tiscus. Tlie
circulating currents can be seen in the hind
legs.

The larva (PI. 35. fig.19), which is aquatic,
is of a dirty-white colour, long, narrow, aud
depressed, resembling a small centipede ; it
consists of thirteen segments including the
head. Its antennae are filiform aud four-
jointed ; the eyes numerous and tub;-rcular,
grouped on each side of the head. The
three pairs of legs are attached to the eight
anterior segments of the body ; the remain-
ing segments are furnished on each side
with a branchial filament, excepting the
last, which has two of them, and four mi-
nute conical points, bent downwards, and
used by the insect when in motion.

BiBL. Westwood, Introd. i. 105; Ste-
phens, Br. G'oleop. 7e>.

GYROC'ORiy, St.— A genus of Peri-
trichous Infusoria.

Char. Free, with one or more spiral or
circular wreaths of cilia, stylate poste-
riorly.

G. o.vyicra. With anterior eye-spot ; mo-
tion revolving, rapid. Stagnant water.
(Kent, Lif. U40.)

G YRODAC T YLUS, Nordm.— A genus
of Trematode Eutozoa.

G. aurivulutns (PL 21. fig. 7) is often
foimd adhering to the gills of fishes, as the
carp, stickleback, &c.

BiBL. Dujardin, Helminth. 480; Wa-
gener, Qn. M. Jn. l60l, 19G; Cobbold,
Faras. 465.

GYROPH'ORA, Ach.— A genus of
Phylloidei (Lichenaceous Lichens), com-
bined with UmbiUcaria by many authors.

GYliOPOREL'LA, Gumbel.-A small
cylindrical Foraminifer, belonging to the
iJactijloporiyia, and consisting of ring-like
segments traversed by simple canals. Its
several species constitute large masses of
Triassic limestone in the Alps.

BiBL. Giimbel, Abh. Miinchen, xi. 268.

GYR'OPUS, Nitzsch. — A genus of man-
dibulate Auoplura (Insects), of the family
Liotheidae.

Char. Tarsi two-jointed, -n-ith a single
claw.

Mandibles without teeth ; maxillary palpi
conical and four-jointed; labial palpi none;
antennae four-jointed; thorax two-jointed;
abdomen eight-jointed.

G. ovalis (PI. 35. fig. 8). Head ferrugi-
nous, transverse, with a lateral produced
lobe on each side ; thorax and legs ferrugi-
nous; abdomen nearly orbicular, yellow-
ish white ; claws long, curved, and strong ;
length 1-48"; found on the guineapig
(Cavia cvbaj/a).

G. yraciUs. Head and thorax ferruginous;
abdomen elongate, segments with a trans-
verse striated iDand at each suture ; claws
very short and minute; length 1-36"; also
on the guineapig.

3 other species : on the agouti, the sloth,
and the peccary.

BiBL. Denny,Anqplur.Monu</r. ; Megnin,
Paras. 94.

GYROSIG'MA, Hass. See Pleuro-

SIGMA.

H^MALASTOR.

[ 3G9 ]

ILEMATOPINUS.

II.

H.EMALAS'TOPt, Kocli.— A genus of
Ixodea (Acariiia) ; -with the body of male
entirely covered by a shield, yellow or red;
no emargrination in front ; eyes clear and
conioal. Two species ; on bats &c., Brazil
and Hun^arv. ( Murray, Ec. Ent. 198, figs.)
H.EMAPHY'SALIS, Kocli.— A genus
of Ixodea (A carina) ; with the palpi very
small, almost broader than long, three-
cornered, the posterior margin of the second
joint expanded outwards.

H. rosea. West Indies (Murray, Ec. Ent.
200, fig.).

H^E'M ATINE.— The red colouring-mat-
ter of the blood, in tlie globules of which it
exists combined with globuline. It pos-
sesses no morphological characters.
BiBL. See Chejiistby.
H.EMATOCOC'CUS. See Pkotococ-
cus and Glceocapsa.

H.EMATOTDINE.— This substance, to
which Mrchow first drew attention, is not
uuf requeutly met with in masses of extrava-
sated blood which have remained for some
time in the living bodies of the Vertebrata,
as in old apoplectic clots, sanguineous ex-
travasations resulting from contusions and
wounds, the eft'usions accompanying the
rupture of the Graafian vesicles, &c.

It occui's in the form of granules, globvdes,
and distinct crystals. These are somewhat
highly refractive, and mostly of a ruby-red
or yellowish-i'ed colour; they are stated also
to have been found colourless. The most
common forms are represented in PI. 13.
fig. 16, and they appear to belong to two
distinct systems — the oblique rhombic pris-
matic, and the regular system.

The properties of haematoidine are as
inconstant as the crystalline form ; and it is
probable that several diflferent substances
have been ranged under the above title, or
perhaps modifications of the same substance
in different states of hydration ; for so insu-
perable has Iseen the difficulty of obtain-
ing haematoidine in quantity and a state of
purity, that its true natm-e has not been
satisfactorily determined. By some it is
considered as bilirubine, or a modification
of it.

It is mostly insoluble or difficultly soluble
in water, alcohol, ether, acetic and dilute
mineral acids, and solution of potash. Some-
times it is soluble in acetic acid, with a
yellow colour, at others readily so in water.
It contains no iron.

An amorphous colourless proteine sub-
stance is som.^times separated from the crys-
tals by the action of mineral acids.

Hfematoidine maybe artificiaUy procured
from various sources, perhaps most readily
from the blood of fishes by spontaneous
evaporation. The blood of the spleen of the
horse changes almost entii'ely into prismatic
crystals of it in dr\nng. In obtaining the
crystals the presence of the serum is prej u-
dicial, and it should be washed away with
a small quantity of water. If recently dried
blood be treated with a vegetable acid
(acetic, oxalic acid, &c.), and a drop of the
solution be placed upon a slide, covered with
thin glass, and kept at a temperature of 80°
to 100° F.,the crystals may also be obtained.
This reaction might be of use in judicial
investigations. The addition of water and
a little alcohol or ether to the blood,
sometimes favours the separation of the
crystals.

Crystals of hfematoidine (?) have been
found within the blood-globules prior to
the addition of reagents.

Their preservation is difficult ; it is best
effected by washing them with alcohol, or
this liquid somewhat diluted with water,
and drying them under the air-pump, or
over sulphuric acid.

BiBL. S'irchow, Ann. Clicm. u. Pharm.
18-51 (Chem. Gaz. 18-32) ; Funke, Zeitsch.
f. rat. Med. 1851, i. 172, 18.52, ii. 109 &
288 ; Kuude, ibid. 1852, ii. 271 ; Lehmann,
G/Hclin^s ITatidb. viii. ; Sanderson, Edinb.
Mn. Jn. xiii.216, 521 ; Kolliker, Mik. An.;
Teichmann, Zeits. f. rat. Med. 1853, iii.
375 ; Frey, Histol. 1876 ; Preyer, Blut-
Kn/stalle ; Hoppe-Seyler, Anal. Chini.
1877, 242.

H^EMATOPTNUS, Leach.— A genus of
Insects, of the order Anoplura, and family
Pediculidee.

Char. Legs all formed for climbing ; tho-
rax generally narrower than the abdomen,
and distinctly separated from it ; abdomen
composed of eight or nine segments.

This genus contains several species (28
Megn.), which live as parasites upon various
animals — the field-mouse, rat, dog, ox,
horse, ass, calf, hog, rabbit, hare, squirrel,
&c.

H. Sills (PI. 35. fig. 4 ; fig. 4*, anterior
leg). Dusky ferruginous ; abdomen grey or
ashy-yellow, flat and membranaceous, with
a black horny excrescence surrounding each
of the v/hite spiracles ; legs long and thick ;
femur transversely striped ; tibiae very ab-

2b

H^MATOPOTA.

[ 3'0 ]

HAIR.

ruptly clavate, dark-coloured at tlie end ;
tarsi with a large fieshy pul villus.

Found upon pigs out of condition ; length
1-10 to 1-6".

BiBL. Denny, Anopl. Brit. 21 ; Gervais,
WalcTcendur s Apteres, iii. 301 ; Megnin,
Paras. 76.

H^MATOPO'TA, Meig.— A genus of
Dipterous Insects, of the family I'aba-
nidse.

Distinguished by the six-jointed antennae,
which are longer than the head, with the
third joint thickened at the base.

H. pluvialis, of which most persons must
have experienced the pungent bite in or
near woods in warm weather, is interesting
on account of the great development of the
lancets, and the beautiful iridescence of the
eyes.

H^MATOZO'A, See Blood, p. lOo, &

FiLAEIA, p. 321.

H^'MINE.— This consists of hydro-
chlorate of hsematine.

ILEMO'CHARIS, Sav. {Piscicola,
Blainv.). — A genus of Annulata.

H. jn'scmm (Piscicola geometra ) is a leech-
like animal, found upon the cai"p, tench,
roach, &c. Length 1 to 2".

BiBL. Leo, Mailer's Arch. 1835 ; Leydig,
Siebold tind Kdllikers Zeitschr. i. ; Bright-
weU, Ann. N. H. 1842, ix. 11.

H^MOGLO'BINE. See Blood, p. 102.

H^'MOPIS, Sav.— A genus of Annu-
lata.

If. sanffuisorba, the common horse-leech.
In this animal the teeth are less numerous
and more obtuse than in the medicinal
leech (Hirudo officinalis).

HAIL. — The microscopic structure of
hail-stones does not appear to be uniform.
In some a central nucleus surrounded by
concentric layers has been noticed ; in others
the nucleus is enveloped by a radiating crys-
talline crust; or, again, the entire mass has
been found to consist of little spheres of ice.
When hail-stones liquefy, a copious evolu-
tion of gas takes place. Hail-stones may
best be collected for examination in a
blanket, which being a bad conductor of
heat, retains them longest in the solid state.
Connected with the structure and formation
of hail-stones, is the composition of spherules
of condensed vapour. These are generally
believed to consist of films of water enclos-
ing portions of air; but AValler's observations
have led him to the conclusion that they are
simply composed of water. If tlie former
view were con'ect, those hail- stones which

consist of aggregations of icy spherules,
should contain air within them, which does
not appear to be the case ; but in deciding
this question, attention must be paid to the
principles laid down in the Introduction,
p. xxxvi,/., which atford a simple means
of deciding the point.

In some liquefied hail-stones, the spores
of fungi and algae, with infusoria, have
been found.

BiBL. Pouillet, Elem. d. Phij.tique, ii. ;
Waller, Phil. Tr. 1817, 23; id. Phil. Mar/'.
1846, xxix. 103, and 1847, xxx. 159 ; Har't-
ing, Skiz. aus d. Natur.

HAIR OF Animals. — The structure of
the hair of animals is very complicated, and
requires careful manipulation for its investi-
gation. We shall commence with the hair
of man, in which it has been the most per-
fectly examined.

Human hair. When a hair is viewed
imder a low power, it appears black at the
sides and light in the middle, so as to convey
a notion of its being a tube: such is not,
however, the case, although this notion was
long admitted.

The hairs are secreted by the skin, and
consist of modified epidermic formations.
Each is implanted in a cutaneous depres-
sion, termed the hair-foUicle (fig. 292), at
the bottom of which it is fixed by a dilata-
tion called the knob or bulb of the hair (c).
The free portion, or that projecting bevoud
the skin, is the shaft or scape {a) ; and' that
above the bulb but contained within the
follicle, is the root (b). The bulb encloses
or suiTOunds a conical or roirndt-d body (?j,
the papilla or pidp.

Three varieties of hair are met with upon
different parts of the body: 1, consisting of
long, soft hairs, from 1 to 3" and more in
length, as tlie hair of the head ; 2, short,
rigid and thicker hairs, from 1-4 to 1-2" in
length, as in the eye-lashes ; and 3, short,
very slender hairs, from 1-12 to 1-6" in
length, as in the down or woolly hairs of
the face, the back and extremities.

When the shaft of a hair is examined
under the microsoope by transmitted light,
two structures are mostly distiuguishable,
a median, more or less black, somewhat
u-regularly granular and linear portion — the
medulla or pith; and an outer, fibrous-
looking portion, mostly more or less co-
loured according to the colour of the hair
— the cortex, cortical or fibrous portion.

The cortical portion is that upon which
the firnmcss, elasticity, and coloiu- of the

fL\IR.

[ 371 ]

PLVIR.

hair depends, and constitutes the greater
portion of its bulk. It exhibits numerous
longitudinal striiie, or interrupted dark lines
and dots. When acted upon by strong sul-

Fig. 292.

I

i

i»v.

a

MagnifleJ 50 diameters.

A hair of moderate size, contained in its follicle, a,
shaft ; b, root ; c, bulb or knob ; d, cuticle of the hair ;
c, inner sheath of the root ; /, outer sheath of the root;
g, structureless membrane of the hair- follicle ; h, trans-
verse- and longitudinal-fibrous layer of the same ; i, pa-
pilla ; k, exc' etory ducts of the sebaceous glands or
follicles, with their epithelial and fibrous layer; I, cutis
of the orifice of the hair-follicle ; m, rete mucosum ;
n, cutaneous epidermis; o, termination of the inner
sheath of the root.

phuric or some other acid at a gentle heat,
it becomes at first resolved into plates or
fibres (tig. 293 B) of the most varied sizes,
both as t^o length and breadth ; but if the
action of the acid be continued, these fibres
become separated into cells (tig. 293 A).
These cells present imeven surfaces, and a
more or less eliptical outline, thek true

form being spindle-shaped ; but they are
mostly flattened and angular, or curved from
mutual pressure, resulting from their aggre-
gation into the shaft of the hair. The cells
are about 1-500 to 1-300" iu length, and

Fig. 293.

Magnliied 330 diameters.

Plates and cells of the cortical substance of a hair,
after treatment with acetic acid. A, separate cells.
1, front view (three of them isolated, two united); 2,
side view. B, a layer, composed of several cells.

from 1-6000 to 1-2200" in breadth. They
mostly contain elongated, dark-looking nu-
clei, 1-1100 to 1-400" in length ; these are
well seen in a coloui-less hair, heated with
soda or potash (fig. 294 A h, and B) ; iu
coloured hair they also contain pigment-
granules, to which the coloiu' of the hair is

2b2

HAIR.

[ 372 ]

HAIR.

principally owing. The pigment-granules
are exceedingly minute, about 1-50,000" in
diameter, rounded, and, as existing in the
hair, are mostly arranged in linear groups.

Fig. 294.

& #•

Magnified -350 diameters.

A^ Portion of a white hair after treatment with soda,
o, nucleated rells of medulla, free from air; 6, eortieal
substance with fibrillation and linear nuclei ; c, cuticle.
B, three isolated nuclei from the cortex.

their colour and numher varying with that
of the hair. The pigment- granules are best
separated by the action of caustic potash or
soda, and they frequently exhibit molecular
motion.

The striated and dotted appearance of the
shaft of hairs is not produced simply by ihe
nuclei, nor by the pigment, but arises in
part also from the unequal lefraction of the
light by the various parts of the cells, and
from the presence of minute spaces filled
with air. The nature of each can always be
determined by attention to the principles
laid down in the Iathoduction.

Towards the bulb, the cells of the cortex
are more distinct, less elongated, and, as Avell
as the nuclei, more easily isolated when
treated with acids, (fig. 205), whilst in the
bulb itself they are round (fig. 29G), 1-4000
to 1-1800" in diameter, closely crowded,
and sometimes containing o)ily a colourless
nucleus, at others pigment-granules.

The ineduUa, like the cortex, consists of a
number of cells. Its structure is best ob -
served in a hair which has been treated with
soda or potash. The cells are then seen Lo

Fig. 295,

Fi''. 96.

Magnified 350 diameters.

Fig. 295. Two striated cells from the cortex of the root

close above the bulb, with nuclei.
Fig. 29*5. Cells from the deepest portions of the bulb;

a, from a coloured bulb, with pigment-granules and

partly concealed nuclei; 6, from a white hair, with

distinct nuclei and a few granules.

be arranged in one or more linear series
(fio;. 294 a) ; they are angular or rounded,
1-2000 to 1-1000" in diameter; and if the
action of the alkali has not been too long
continued, they exhibit a nucleus ; they fre-
quently also contain one or more granules or
globules of fat (fig. 297). In the shaft and

Fig. 297.

Magnified ;J60 diameters.

Medullary cells with pale nuclei and fatty granules,
from a hair treated with soda.

upper part of the root of the hair, tliese
cells contain air, -which gives them a dark or
black appearance by transmitted light ; and
it was the generally received opinion, u)itil
we pointed out the error several years ago,
that this darkness or blackness arose from
the presence of pigment. The contrary,
however, may be easily proved by mace-
rating the hair in oil of ttirpentine or any
liquid, when the air escapes in bubbles and
becomes displaced by the liquid ; moreover,
on drying the hair, the air and black ap-
pearance return. I'l. 29. fig. 1 repre-sent.s a
white haiiv in ^^ liich the medullaay cells of

HAIR.

[ 373

HAIR.

the lower part are filled with Canada bal-
sam, whilt^t those of the upper portion still
contain air. Again, examination by reflected
light is equally conclusive ; for \uider it the
black nu'dullary portions become w-hite,
which would not be the case did the black-
ness arise from pigment. PI. 29. (ig. 9 illus-
trates this .in the hair of the Lion ; where
a represents the hair as seen by transmitted,
and h by reflected light.

Cidicnlar coat. The shaft and root of
the hair, above the termination of the inner
root-sheath, are coated externally by a
firmly adherent, thin, simple, membranous
layer, consisting of flat, imbricated, epithe-
lial scales. In the natural state of the hair,
the existence of these scales is only indi-
cated by the presence of irregularly trans-
verse and anastomosing lines seen upon the
surface, or slight dentition of the margin
(tig. '2-JSA). But when the hair has been

Fig. 298.

Fig. 299.

Magnified 160 diameters.

A. surface of the shaft of a white hair, the curred
lines indicating the free margins of the epidermic scales.
B, scales isolated by the action of soda.

treated with an acid or an alkali, the scales
become separated. Their free margins are
directed towards the unattached end of the
hair. The scales are much more distinct
without treatment, in the hair of the newly-
born infant (PI. 29. fig. 3). They are very
transparent, somewhat quadrangular, flat-
tened or curved cells (fig. 298 B), not
containing a nucleus ; theii* margins or edges

Magnified 250 diameters.

Portion of the root of a dark hair, slightly acted upon
by soda: o, medulla, the cells still containing air; h,
cortex with pigment; c, inner cuticular layer; rf, outer
eutieular layer ; e, inner layer of the inner root-sheath ;
f, outer perforated layer of the same.

are often black, and, as the other parts
are transparent, they are apt to be over-
looked. They are about 1-700 to 1-500" in
length, and one half or one third of this in
diameter.

In the lower part of the root, below the
termination of the root-sheath, the cuticu-
lar coat is double, or consists of two layers.
The above-mentioned cuticle of the shaft
and upper part of the root forms the con-
tinuation of the innermost of these, which
possesses nearly the same structure, except
that the scales of which it consists are some-
what longer, and directed more obliquely
outwards. These layers are best seen in a
hair treated with an alkali, especially with
the aid of pressure ; they then become se-
parated (fig. 299), the inner, with the roo
of the hair, assuming an undulating form,,
and remaining firmly adherent (c), whilst
the outer (d) remains attached to the inner
root-sheath, its cells also being broad and
without nuclei. At the bulb, both these
layers become transformed into soft cells
broader than long, with transverse nuclei
finally becoming fused with the round cells
of the bidb.

HAIR.

[ 374 ]

HAIR.

The hair-foUides are pouches, about 1-10
to 1-4" in length, pretty closely surrounding
the hairs, and extending in the short hairs
into the substance of the upper layer of the
cutis ; but in the long hairs, into its deepest
portion, or even into the subcutaneous cel-
lular tissue. They may be regarded as pro-
longations of the skin, with its components,
the cutis, basement-membrane, and epider-
mis. Hence three parts are distinguishable
in them : an external, fibrous, very vascidar
portion — the proper hair- follicle ,• a base-
ment-membi'ane ; and a non-vascular cellu-
lar coat — the epidermis of the follicle, or,
because it surrounds the root of the hair,
the root-sheath.

The fibrous portion of the follicle con-
sists of two layers or membranes. The
outer one (fig. 292 /<) is the thicker, and
contains vessels and nerves. Its inner sur-
face is connected with the inner layer; ex-
ternally it is attached to the surrounding
areolar tissue ; and above, it is continuous
with the outer layer of the cutis. It con-
sists of common areolar tissue, the fibres
of which are longitudinal, with elongated
spindle-shaped nuclei. The inner layer
(tig. 300 «) is much more delicate, and only
extends from the base of the hair-follicle
to the orifice of the sebaceous follicles. It
consists of a single layer of transverse fibres,
with long and narrow nuclei, resembhng
unstriated muscular fibres.

The third layer (fig. .300 6), or basement-
membrane, is transparent and structureless,
and extends from the base of the follicle,
without apparently covering the papilla, as
far as the inner root-sheath, and perhaps
higher. It presents delicate transverse
anastomosing lines, producing a fibrous
appearance.

The pulii or papilla of the hair (fig. 292 i)
belongs to the follicle, and corresponds to a
papilla of the skin. It is rounded or oval,
1-96 to 1-480" in length, is connected with
the fibrous coat of the follicle by a kind of
stalk, and consists of indistinctly fibrous
areolar tissue with nuclei and granules of
fat, but contains no cells.

The two root-sheaths consist of the epi-
dermic covering of the hair-follicle. The
outer (fig. 292/) is the continuation of the
rete mucosum of the skin, and lines the
entire follicle. Its lower part is in contact
externally with the basement-membrane of
the follicle ; but above the termination of
the inner transverse layer of the follicle, it
is in direct contact with the outer or longi-

tudinal layer. It consists of several layers
of nucleated cells, resembling those of the
rete mucosum of the skin, the outer having
their long axis perpendicular to that of the
hair, the others, especially towards the bulb,
being roimded. This outer root-sheath is
most distinct in the follicles of the skin of
the negro, from which it may be withdrawn
with the epidermis after maceration.

Fig. 300.

Magnified 300 diameters.

Portion of the inner fibrous coat and basement-mem-
brane of a hair-follicle : a, inner coat with transverse
fibres and elongated transverse nuclei; b, basement-
membrane, seen as it were in section ; c, its lacerated
margins ; d, fine lines (fibres ?) on its inner surface.

The inner root-sheath (fig. 299, e,f) forms
a transparent, very firm and elastic, yellow-
ish membrane, extending from near the base
of the hair-follicle to near the mouths of the
sebaceous follicles, where it terminates ab-
ruptly with a jagged margin. Externally
it is connected with the outer root-sheath,
internally with the outer layer of the cuticle
of the hair ; hence no interval exists natu-
rally between it and the Jiair. At first sight
it appears as a perfectly homogeneous mem-
brane, but on closer examination it is seen
to be distinctly cellular ; it consists of two

HAIR.

[ 375 ]

HAIR.

or three layers of polygonal, longish, trans-
parent cells, with their long axis parallel to
that of the hair. The outermost (Ilenle's)
layer (figs. 299/, 301 A) consists of long,

Fig. 301.

mfmi

n iilll

J)

\:f'^

Magnilicd 350 diameters.
Elements of the inner root-sheath. A, external layer :
1. isolated pirates ; 2, the same in connexion, showing
the int^^rspaces (a) between the cells (6). -B, cells of the
inner non-perforated layer. C, nucleated cells of the
lower part of the inner sheath, which consists of a single
layer only.

flattened, non-nucleated cells, from 1-700
to l-oOO" in length, with fissures between
them, forming a fenestrated layer. The in-
nermost (Huxley's) layer (figs. 299 e, 301 B)
consists of one or two layers of shorter and
broader polygonal cells, from 1-1200 to
1-600" in length ; their nuclei, which exist
in the lower part only of the coat, are often
broader at the ends than in the middle,
sometimes curved and pointed. At the base
of the hair-foUicIe, the inner root-sheath

consists of a single layer only of beautiful,
polygonal, nucleated cells (fig. 301 C) ; tliese
becoming soft, delicate and rounded, gra-
dually pass into the outer layers of the round
cells of the bulb.

In regai'd to development, the rudiments
of the hair appear as processes of the rete
mucosum descending in the substance of
the cutis. These are solid, and consist of
cells, the internal of which become horny,
and form first a small slender hair in the
axis of the process, next an inner sheath
sm-rounding the former, whilst the outer
cells remain soft, and form the outer sheath
and the cells of the bulb.

After birth the foetal hair appears to be
completely shed, new hairs being formed in
the old follicles, which displace the first set,

as shown in figs. 302, 303.
Fig. 302.

Fig. 303.

Magnified 20 diameters.
Eye-lashes of a child a year old. A exhibits a process
(jn) of the bulb or outer root-sheath, in which the cen-
tral cells are elongated, and form a cone distinct from
the outer cells. -S, one more advanced, in which the
inner cone has become developed into a hair and an
inner root-?heath : a, outer, b, inner root-sheath of the
young hair; c, pit for the pulp; c?, bulb; e, shaft of the
old hair; f. bulb, .9, shaft, h, summit of the young hair;
i, sebaceous follicles ; k, three sudoriparous ducts open-
ing into the upper part of the hair-follicle.

The hairs sometimes found developed
upon mucous membranes, and within en-
cysted tumours and ovarian cysts, possess
the normal structure in every respect.

Of the morbid states of the human hair,
we need mention only the loss and change

HAIR.

[

]

HAIR.

of colour, and tlie presence of fungi. When
the colour entirelj^ vanishes, and. the hair
becomes white or grey, the cells of the me-
dulla contain abundance of air. This arises
from degeneration or impaired nutrition ;
the liquid contents of tlie cells are not sup-
plied in sufficient quantity ; they therefore
evaporate, and the cells being pi-evented
from collapsing by their adhesion to each
other and to the hrm cortex, become filled
with air, which replaces what would other-
wise constitute a vacuum. Fungi are found
in Favus upon the cortex of the hair,
Avithin the follicles, and even within the
hair itself, as is stated. In Porrigo decal-
vans also, fungi are stated to occur in the
hairs.

The principal differences between the bair
of man and of animals, and that of animals
from each other, relate to — 1, the size; 2,
the relative proportions of the cortical and
medullary structures; 3, the locality of the
pigment; 4, the arrangement of the medul-
lary cells ; 5, the comparative amount of
true hair, and wof)lly hair, down, or wool ;
and 0, the size and projection of the super-
ficial cortical cells or scales.

Of these we shall give a brief sketch
(PI. 1. figs. 1-3, and PI. 29).

The hair of the INIammalia generally is
formed upon the same plan as that of man ;
great variety, however, exists in its com-
plexity of structure and the arrangement of
the component parts.

Qvadnnnana (PL 29. figs. 4 & 5). In the
monkey (Indian) (fig. 4), the hair presents
much of the same structure as in man; the
pigment is confined to the cortex, but the
air-cells of the medulla are larger a,nd less
crowded ; this is seen to a greater extent in
the hair of the lemur (fig. 5).

Cheiroptera. In the bats (PL 1. fig. 2;
PL 29. figs. G & 7), a striking character is
the peculiar development of the cortical
scales of the surface. In the hair of the
common bat (PL 1. fig. 2), Avhich is one
of the Test-objects, and Australian bat
(PI. 29. fig. 7), this character is not so
striking as in that of the Indian bat (fig. G),
in which the scales are grouped in whorls
at pretty regular intervals along the shaft,
and project considerably beyond the sur-
face. The pigment is principally confined
to these whorled scales. In some of the
white hairs of the bat, the individual scales
are very beautifully seen (PL 1. fig. 2 c).

Insectivora. The hair of the mole (PL
29, fig. 8) bears some resemblance to that

of the bats : but the cells of the medulla
are very distinct. (See Spixes.)

Carnivora (figs. 9-13) . In this Order the
structure of the hair varies considerably.
In the lion (fig. 9) the cortical cells are di-
stinct, but not projecting; the medullary
cells are very niunerous, and the air-spaces
minute, but closely aggregated, as we often
find them in the human hair. In the bear
(fig. 10), the large hairs present much the
same structure as in the lion ; the wool-
bairs difier strikingly from these, however,
in the distinctness of the cortical and me-
didlary cells.

Fachydermata (figs. 14-17). In this Order
the hairs present a development correspond-
ing with that of the skin; being very thick
and complex in structure. In the elephant
(fig. 15, transverse section), each hair re-
sembles a number of hairs fused together.
Scattered through its substance are pale
spots formed by cells containing little or no
pigment, with an irregidar perforation in
each, probably arising from rupture of the
cells. Surrounding these medullary centres
are innumerable cortical cells loaded with
pigment. In the jjig (fig. 16), the distinc-
tion between the cortex and meduUa is not
well raarked,_and the cells assimie a radial
direction, as indicated by those which con-
tain most pigment. In the Cheiropotamus
(fig. 17) the distinction is more evident.

Rmninantia (figs. 18-22). In this Order
the hair presents great variety. In the
camel (fig. 18) and dromedary (fig. 19), the
true hair exhibits much the same structure
as that of the higher Orders, whilst in the
deer (fig. 20, moose-deer; fig. 21, musk-deer)
the medullary portion is enormously deve-
loped at the e.Vpense of the cortical p'ortion ;
in no hair is the cellular structme more
distinct than in the two latter, the medulla
closely resembling a piece of vegetable cel-
lular tissue. The wool-hair in this class
presents the characteristic structure. That
of_ the camel (fig. 18 b) agrees in structure
with the type of wool from the sheep
(fig._ 22) in its softness, flexibility and
waviness, and in the disthictuess of the
cortical cells.

Edentata (figs. 23 k 24). The difierence
between the hair of the three-toed sloth
(fig.' 23) and that of the armadillo (fig. 24)
is well-marked. In the former, the cor-
tical cells take a remarkably oblique or
radiating course, whilst in the latter thej
run longitudinally.

Eodentia (figs.' 2o--35), In this Order the

HAIR.

[ ••''77 J

IIAIII.

pigment is met with sometimes iu the me-
diiihx, at others in the ciu'tex. The arrange-
ment of the air-cells is often very beautiful,
and has reridered these hairs favourite
microscopic objects. Portions of a mouse-
hair in various parts of its length are re-
presented in Hg. 27, a forming the free end.
Fig. 28 displays two portions of the same
haTras histolyzedby treatment with solution
of potash. The cortical parts have not been
resolved into their component cells, whilst
those of the medulla have assumed their
rounded and natural form, and exhibit mi-
mite grannies of pigment, with larger glo-
bules of fat. The arrangement of the me-
dullary cells iu two rows is seen in fio-. 28 b.
The pigment within the cells in situ is seen
iu tig. 31 b, from the rabbit. l"he wool
presents its characters in a marked degree,
the projection of the outer layer of cortical
cells and the distinctness of the medullary
air-cells being very evident.

Marsitpialia (lig-s. 30 & 37). In this cu-
rious Order the hair greatly resembles that
of the Rodents. That of the kangaroo pre-
sents very beautifully imbricated cortical
cells (fig. 36).

Monotrernata. The structure of the hair
of the Ornithorhyuchus is as peculiar as
that of the animal in general. It presents
that of hair and avooI combined (tig. 38).
The basal portion resembles wool, and is
very long and narrow ; the structure of two
pieces in different parts of its length is seen
in fig. 38 c and d. At the end of this por-
tion is attached the proper hair containing
the pigment within the cortical substance
(b) ; tig. 38* represents the surface-view of
the hair, showing the imbricated scales.

In Birds the hair is replaced by fea-
thers.

The hair of the Invertebrata does not
present the same structiu'e as that of the
higher animals ; some physiologists have
therefore limited the term hair to the fili-
form epidermic formations of the Mam-
malia, whilst others admit the occurrence
of hair in all classes of the animal kingdom.
At all events, the hairs of the Invertebrata
are not usually cuuiposed wholly of epider-
mis. They consist of an outer cortical or
epidermic layer, frequently coloured, and
upon which their firmness depends ; lining
this is sometimes a prolongation of the
cutis, at others a colourless substance which,
when the hair is dried, presents an irregular
cell-like appearance and contains air, so as
to resemble the air-cells of the hair of the

jNlammalia. In other instances the Lair is
completely solid, but exhibits no trace
whatever of cell-structure. It remains to
be shown whether the latter may represent
the epidermis hardened in an amorphous
state, and whether those lined with cutis
may be regarded as epidermic formations
upon an exserted papilla of the skin ; whilst
those presenting the air-cells when dried
correspond to an outer hardened epidennic
layer, and an inner retaining its distinctly
cellular state. In those lined with cutis,
the circiUation can sometimes be observed.
We have space to notice only a few in-
stances of variety of form, many of which
occur, and have long rendered these hairs
interesting and elegant microscopic objects.
Thus, in some of the Arachnida they are
feathery, giving oft' slender lateral branches,
as in Lycosa (PI. 29. fig. 40), Epeira (PL 6.
fig. 8 5), Acanis (PI. 6. fig. 1 i), &c. ; in
others these branches are directed forwards
near the middle of the shaft, but recurved
at the end, as in Mygale (the bird-catching
spider) (PL 29. fig. 41); or, while the
branches on the shaft resemble the above,
the end of the hair is thickened, cylindrical
and longitudinally striated, with minute
setae arising from the strijB, as in fig. 42 ;
again, some of them are simple, but fur-
nished with spiral striae {E'peira, PL 0.
fig. 8 «) ; in Tromhidium they are sometimes
very elegantly feathery.

In Insects, Arachnida, kc, they often
appear to rise from a bulb at the base ; but
the bulb is not solid, and bears no resem-
blance in structure to the bulb in the
Mammalia; it consists of a thickening or
fold of the ejjidermis of the skin, not of the
hair, from which it is separated by a white
ring, indicating thinness of this coat, and
often corresponding to a joint; the hair
arises from the base of a depression situated
within the annular bulb. The hair of some
of the larvse of the Dermestidae is very
beautiful, and is used as a Test-object.
Two forms are met with : in one (PI. 1.
fig. 1 c) the shaft is simply covered with
densely aggregated, minute, spinous secon-
dary hairs; in the other (PL 1. fig. 1 «, b),
the spines or scales upon the shaft are nar-
row, acute, and placed in pretty regular
whorls; in the uppermost whorl they are
broader, the spines remaining as midribs,
whilst the margins are more developed, the
whole resembling a flower with four or five
petals ; but at the end of the hair, the
scales are longer, narrower, and recurved,

HAIR.

[ 378 ]

HAIRS.

eacli midrib being terminated below by a
little knob.

The examination of the hair and its dis-
section can only be effected by the aid of
chemical reagents, especially sulphuric acid,
solution of potash or of soda. These should
first be used cold ; and if no separation of
the components ensues, heat even to boiling
must be apphed ; the subsequent addition of
water is sometimes advantageous. Sections
of hair can be made with a razor, a bundle
of hair being fixed between two flat pieces
of cork, or between two cards. Transverse
sections of the human hair can be obtaiued
by shaving a second time, an hour or two
after the first ; the sections should then be
washed in water. The cortical cells are
most beautifully seen in white hairs which
have been thoroughly soaked in oil of tur-

?entine, and mounted in Canada balsam,
'he air-cells of the medulla are best ob-
served in hairs which have been mounted
in balsam without the previous application
of turpentine. The sheaths of the hair
keep best in solution of chloride of calcium
or glycerine.

Many of the structures of the hair of the
Mammalia may be well observed in the
large hairs or bristles (whiskers) of the ox,
&c. ; in these also the pulp is seen to contain
blood-vessels, which have not been detected
with certainty in that of man. They also
exhibit bands of smooth muscular fibres,
arising from the cutis, descending through
the hair-follicles, and terminating below
the sebaceous follicles, forming the erectores
pili.

The hairs of some animals polarize light.
An interesting object of this kind may be
made by placing two series of the white
hair of a horse in balsam, so as to cross
each other at an angle, and viewing them
by polarized fight (PI. 39. fig. 39).

In regard to the discrimination of the
hairs of one animal from those of another,
we believe that the examination of indi-
vidual hairs can in general be but little
depended upon ; whilst a comparison of
their form, length, and breadth, with the
proportion of the true hair to that of the
wool, conjoined with the consideration of
the internal structure, may often enable
an observer to arrive at a satisfactory con-
clusion.

BiBL. KiiUiker, Mikr. : Eble, Haare in
d. (jesammf. organ. Nutur ; Ilenle, Allff. An. ;
Todd & Bowman, Phys. of Man-, Erdl,
Miinchen. Ahh. Bd. iii. ,; Huxley, Med. Gaz.

1845 ; Griffith, ibid. 18J8, 844 ; Heusinger,
Histol. ; Gurlt, Miill. Archiv, 1836 ; Aikin,
Arts and Mamif. ; Bonders, Mtdder's Fhy-
siol. Chem.; Be Morgan, Phil. Tr. 1859
(Cmstacea) ; Pfaft^ D. mensch. Haar. in
2^hys., pathol., ^ forem. Bedeut. 1869 ;
Goette, Schultze's Archiv, 1868, 273 ; Bie-
siadecki, Strieker's Ilandb. 600 ; Ilofmann,
M. M. Jn. 1873, 167 ; Frey, Histolog. 1876,
419 ; Sorby, Jn. Linn. Sac. 1881, xv. 337.

HAIRS OF Plants, trichomata or tri'
chomes. — The term hair is applied in botany
to filamentous productions upon the surface
of the organs of plants, consisting of one
or more ceUs arising out of and constituting
part of the epidermal structure. Hairs of
plants present a great variety of conditions :
ill the simplest kind — those "^ composed of a
simple, cylindrical, conical, bifurcated or
steUate cell — they may be varied in form
by the pecuhar shape of the constituent
cell, in individual character by the presence
or absence of special secretions in the cell-
cavities, and in their collective character by
the mode of arrangement on the epidermis,
since they may be few and scattered, or so
numerous as to form a velvety coat. Com-
jyound hairs, namely those composed of a
number of cells, vary in fike manner, and,
moreover, in the examples where the cell-
walls acquire considerable thickness, pass
gradually from pure hairs into bristles, and
thence into the structures called Thorns
(distinguished from true spines by beino-
appendages of the epidermis). The" stellate
fornis also present many variations inter-
mediate between hairs proper and Scales.

These structures are interesting to tha
microscopist on account of the varietv and
often extreme elegance or curiosity of their
fornis.^ They likeA\-ise strongly attract the
attention of the physiologist from the sim-
plicity of their organization and their free
condition, allowing the phenomena pre-
sented by the cell-contents to be readily
observed under the microscope. In reference
to their characters as microscopic objects,
it Avill siifiice to indicate their principal
modifications, and state a certain number
of exaruples. For this purpose they may
be classified as follows : —

Simple hairs: vnbranched. Cabbage-leaf
(Brassica, fig. .304), (Emdhera, Dicfammts
(VI. 28. fig. 39 a), Anchusa (fig. 17) ; bifin--
cated, Capsella (fig. 36), Draba (tig. 307) ;
inflated or capitate, Antirrhinum ( fig. 306
and PI. 28, fig. 34), Salvia (fig. 305), Helle-
borusfoitidus j branched, in many Crucif era^,

HAIRS.

[ 379 ]

HAIRS.

as Sist/v>hiuin Sophia (fig. 35), AJternan-
thera 'axUlaris (fig. 37) ; stellate, Ahjssum
(fig. 308) . Very often hairs composed of a
single cell are supported upon a sliort stalk,
and tlien developed horizuntally in tAvo
directions, as in Grevillia lithidophyUa (fig.
129) ; in several so as to form a star, as in
Deutzia scabra (fig. 26*), Ahjmim (fig. 28).
Structures analogous to the last occur upon
the septa of the air-cavities of the Nymphte-
aceae, such as Nuphar lutea (fig. 15), Vic-
toria, Szc.

Fig. 304.

Fig. 305.

Fig. 306.

<s

Hairs of: —
Brassica (leaf). Salvia (calyx). Antirrhinum (corolla)*

Fig. 307.

Fig. 308.

Draba (leaf). Aljssum (leaf).

MagniSed 100 diameters.

Compound Hairs. These exhihit a similar
diversity of character, and often imitate, on
a larger scale, the forms of the simple hairs \
they may be wibi-anchecl, as in the hairs of
the garden Pelarcjonia (PL 28. fig. 18), and
a large proportion of ordinary silky hairs
upon'the epidermis of plants. Cotton is a
striking example, consisting of the hairs of
the seeds of Gossijpinm (fig. 1).

Commonly these hairs are cylindrical; but
not unfrequently one or more of the upper-
most or all the component cells are expanded
into a more or less globular form. Capitate
glandular hairs often occur on corollas, and
particularly on the inner scales of leaf-buds :
examples — the bulbils of Achimenes (fig.
32), the corolla of Digitalis (fig. 33), Lijsi-
machia vulgaris (fig. 40), Sci-oi)lmlaria no-

dosa (fig. 41), Bryonia alha (fig. 42), the
inner scales of tlie winter leaf-buds of the
ash, &c. Or the hairs are torulose, as in
Lamium album, the common white Dead-
nettle ; or mouiliform or necklace-shaped,
as on the stamens of Tradescantia (fig. 311)
the Marvel of Peru (Mirabilis, fig. 309).'
The transition from these to the branched
forms is presented commonly in the simpler
forms of the pappus of the Compositfe, as
in that of the Groundsel, which has toothed
hairs ; in other examples the lateral teeth
grow out into branches, as in the species of
Hieracium and other Coniposita3, presentino-
pinnate or plumose forms, according to the
extent of ramification. The seeds of Ca-
talpa Bungeana bear a fringe the hairs of
which resemble Pitted Ducts. Verhascum
Thapsus (PI. 28. fig. 19) has compound hairs
branched at the joints. Compound hairs
likewise exhibit the horizontal development;
the hairs of the garden Chrysanthemum are
horizontal navicular cells, supported on a
tall articulated pedicle (fig. 30) ; the stellate
hairs of the Ivy (fig. 27) are compound, and
supported on a short stalk-cell. \'er3' varied
forms of compound, more or less stellate
hairs occur on the leaves in the orders Jas-
minaceae and Oleaceas. The last form a
transition to the scales of the Eleaonacese
and many Ferns, such as Acrostichum.

Fig. 309.

Fig. 310.

Fig. 311.

Hairs of: —

Mirabilis. Antirrhinum (calyx). Tradeseantia (stamen).

Magnified 100 diameters.

The hairs above noticed are mostly soli-
tary, lu the Malvaceas (iZ'/J/scMs) tufted or
stellate groups of hairs are met with ; and
in the air-cells of Utricularia are seen
curious groups of four hairs. Marruhium
a-eticum is another example of this kind of
structure (fig. 47).

Almost all of the above-described forms
of hair may contain merely watery colour-
less or coloured contents ; or they may have

ITAIRS.

[ P'^0 ]

HAIRS.

one or more of the component cells filled
with special oily, resinous, or saccharine
secretion. In the latter condition they are
termed gkmdidar hairs. The characters of
these organs are spoken of under the head
of Glands and SECRKxiNa OnaANS of
Plants. The gum-resinous secretion found
upon the buds of trees (^sadtis, &c.) is
formed by glandular hairs.

Some of the hairs with watery cell-con-
tents present favourable opportunities for
observing the Rotatiox of the protoplasm;
for example, the young hairs of the stamens
of Tradesvantia or spider-wort ; the sting-
ing hairs of nettles also show this when
young ; and probably it might be observed
in all young hairs, where sutficiently trans-
parent and uninjured. One precaution
greatly facilitates the observation — namely,
to dip' the hairs into alcohol for an instant,
and immediately plunge them in water ;
after this operation, the structure is readily
wetted by water, and no longer obscured by
the abundance of air-bubbles that remain
entangled with and adherent to the surface
of the fresh hairs. These young hairs like-
wise exhibit at their apices the various con-
ditions of the contents (nucleus, protoplasm,
&c.) of cells multiplying by division (PI. 47.
figs. 8 & 0). The circulat^ion takes place in
the dark streaks represented as forming a
network connected with the nuclei («).

Stings, such as those of the Nettle (PI. 28.
fig. 8), consist of simple cells ha^dng a
bulbous base enclosed in a cellular case,
formed by the growing-up of the epidermis
round the base of the hair; the latter tapers
away upward to near the apex, where it
again expands into a little globular head.
The walls are rather thick and spirally stri-
ated. The bulbous base is filled with the
irritating liquid, which exudes when the
knob-like head is broken off, through the
tension of the cellular investment of the
sac.

The intimate structure of the hairs of
plants presents many points of interest. The
cells are of course composed of a cellulose
wall, with contents varying according to
age and other circumstances. When young,
they are always densely filled with proto-
plasm (PI. 47' figs. 8 & 0), which becomes
gradually excavated by vacuoles, and ex-
panded so as to form a mere reticulation or
a few streaks upon the wall, mostly con-
nected with an evident nucleus. The cavity
of the cell is then filled, in hairs proper, with
watery cell-sap, sometimes coloured, as in

the petals and stamens of many flowers, by
the same liquid colouring-matter as the cells
beneath the epidermis; stings are filled with
acrid watery juice, — glandular hairs with
various secretions, which, like the watery
juices, appear at first in vacuoles, gradually
occulting the place of the protoplasm
which follows the expanding cell-walls.

Hairs, being epidermal structures, possess
a more or less evident cuticular layer, which
may be detached by the action of acids
(fig. 199, p. 295); sulphuric acid often
causes this to separate and expand as a kind
of vesicle from the surface of the hair, as is
shown in PI. 28. fig. 1.3 {SiphocampyJus) ;
the cuticle of the full-grown moniliform
hairs of Tradescautia may be separated in
like manner (see Epidermis). This cuticle
also exhibits in many cases the same mark-
ings which occur on the surface of the
epidermis of certain plants, as Helhhorus,
Cakile, &c. (PI. 28. figs. 9 & 10), consisting
of elevated spots, ridges, reticulations, &c.
composed entirely of thickenings of the
cuticular layer. This is well seen in the
hairs of the Boraginacese, e. g. Anchusa
(fig. 17), the Cruoiferas, as of Farsetia,
Cheiranthus, kc, or Dclphinitim (fig. 16).
The spiral striae on the sting of TJrtica urens
(fig. 8) appear to be of similar nature.
T. West has described the raised markino-s
upon some hairs as bulgings or wrinkles in
the cell-wall.

Finally, it is necessary to mention the
remarkable structure of the hairs upon the
surface of the seeds and pericarps of certain
plants among the Acanthaceas, Polemo-
niacece, Labiatse, Compositre, &c. Those
of the Acanthace,^ have been spoken of
partly under that head and under A cax-
THODIUM. They are hairs composed of
cylindrical cells, simple {Ruellia, PL 28.
fig. 21), or conjoined into a compound and
branched hair [Acanthodium, fig. 24), the
cell-walls of which receive when young
a spiral (fig. 24) or annular (fig. 21) fibrous
deposit, and subsequently become partially
disorganized ; so that, if placed in water in
the mature state, the primary cell-wall
almost dissolves into a kind of jelly, and
the spiral-fibrous structure expands' witii
elasticity. The conditions are similar in
CoUomia (fig. 22), and, according to Schlei-
den, in Oilia, Ipomopsis, Pokmonium, Can-
tua, &c. among the Polemoniaccfe ; and
somewhat the same in many species of Sal-
iv'a (fig. 23), Ocgmiim, DracncepJadum mol-
davicum, &c. among the Labiatje. In Cobcea

HALACARUS.

[ 381 ]

IIALIONYX.

scandens, the spiral-fibrous hairs take rather
the form of miiurte scales, ami they do not
spontaneously expand elastically (Pi. 28.
fig. 20). Among the Ooniposit;c, these
spiral-fibrous hairs have been observed on
the pericarp of Huckeiia, some species of
'TrichocUne, Eiiriops, 31eso(/rainma, Doria
Clmfticefolia, OUyothrix gracilis, and some
species of Senecio. Spiral cells also occur
on the seed of JL/drocharis. The best way
to observe the elastically expanding hairs is
to place a thin slice of the skin of the seed
on a slide in a little alcohol, which does not
sot'ten the cell-wall : when the object is in
focus, the addition of a little water causes
the gelatinous softening of the cell-walls,
the spiral hbres fly out from the surface of
the seed-coat and show clearly the charac-
ter of these beautiful objects. The primary
membrane may be detected, even in its
gelatinous state, by adding sulphuric acid
and iodine, which produce a purplish or
violet colour. Further remarks on this head
will be found under Spirai, Stkuctuhes.

The hairs on the stigma of Campamda
are remarkable for the intussusception which
is observed to take place in the mature hairs.
The filiform processes growing from the
under siu-face of the frondose HepaticjB,
the thallus of Lichens, the prothallium of
Ferns, kc, are commonly called radical
hairs. In most cases they present no re-
markable points of structure ; in Marchan-
tia, however, peculiar spiral markings have
been detected (see Marchantia).

BiBL. Meyen, Secretions-oryane d. Pflan-
zen, 1837 ; id. P/ianzen-jjhysiol. ; Cohn, Cu-
ticida, Linncea, xxiii. 3o7, 18o0 ; Schleiden,
Midler'' s Arc/iiv, 1838; Beitr. z. Botanik,
Leipsic, 1844, i. 121 {Sc. Memoirs) ; De-

caisne, Ann. Sc.

Nat. 2 ser. xii,
X. H. vi. 257 ;

251, pi. 4 ;
Brongniart,
pi. 4; Pril-

5; Tuiien
Weisse, I>.

Leighton, Ann.

Ann. Sc. Nat. 2 s^r. xii. 244,
lieux, Ann. Sc. Nat. 4 ser. -^
West, Qu. Mic. Jn. vii. 22;
Pflanzenhnare, 18G7 ; Hanstein, Bot. Zeit.
1868, 6U7 ; Banter, Trichomgeh. 1871;
Martinet, Ann. Sc. Nat. 1872, xiv. ; Sachs,
Bot. 103.

HALACARUS, Gosse.— A genus of
marine Acarina.

Char. Body sometimes covered with a
dorsal shield ; rostrum bulbous, pointed ;
palpi terminated by a fang-like claw; legs
formed f()r walking, arising from the outer
margin of the body, directed two pairs for-
wards and two backwards, and with a pair
of hooks.

Five species : found crawling upon sea-
weeds at low water, or in dredgings.

BiBL. Gosse, 3far. Zool. i. 177 ; Murray,
Econ. Entoin. 205 (tigs.).

IIALAKACH'NE, AUman.— A genus of
marine Acarina ; family Gamasea.

Body elongate subcyliudrical, with an
anterior dorsal plate,

//. halichceri. In the posterior nares of a
seal (Ilalicharus grgphus) ; length 1-8".

BiBL. Aliman, Ami. N. II. 1847, xx.
47 ; Murray, Econ. Ent. 167 (tigs.).

HALECTID.E, Hincks.— A family of
Ilydroid Zoophytes.

Gen. : Huleciuni and OpModes.

HALE'CIUxM, Oken.— A genus of Hy-
droid Zoophytes, family Sertukriid;e.

Distinguished by tlie plant-like polypi-
dom, the stem consisting of numerous
parallel capillary tubes, and the cup-like
nearly sessile cells arising alternately on
opposite sides of the stem, one under each
joint.

H, hulecinmn. Vesicles oval or oblono-.
Common on shells and stones in deep water ;
4-10" high.

H. Bcanii. Vesicles calceohform. Rare.

H. muricatum. Vesicles spinous.

5 other species.

BiBL. Johnston, 5/7^. Zooph.oS: Hincks,
Ilydroid Zooph. 220.

HALIOHOND'RIA, Flem.— A genus of
Sponges.

HALTDRYS, Lyngb.— A genus of Fu-
cacese (Fucoid Algas), containing one British
species, H. siliquosa, common on rocks and
stones somewhat above low-water mark.
It is readily distinguished by its pod-like
septate air-vessels. The fructification, which
is terminal on the branches, much resembles
that of Fucus, except that the interior
of the receptacles is tilled up with hrni
polygonal cellular tissue. The antheridia,
moreover, are terminal on their pedicels,
often in tufts, short in form, and inter-
mixed with spore-sacs in the same concep-
tacle.

BiBL. Harvey,-^;-. Mar. Alg. 15, pi. 1 C ;
Thuret, Ann. Sc. Nat. 3 ser, xvi. 8, pi. 3.

HALIO'N YX, Ehr.— A genus of Diato-
macese.

_ Char. Frustules single; valves equal,
circular, surface radiate, the rays not com-
mencing at the umbihcu.-i; no internal septa.
Marine.

//. senarius. Rays six, the intervenino-
spaces with shorter rays of equal len^-th
parallel to the larger, and with transverse

HALISARCA.

[ 382 ]

HAPLOMITRIUM.

laxly cellular lines ; umbilicus punctate,
entire ; diara. 1-720".

H. iindenarins (PI. 18. fig. 51). Rays
eleven or twelve.

BiBL. Ehr. Ber. Berl. Akad. 1844, 198.

HALISAR'CA, Duj. (Hymeniacidon,
Bowerbk.). — A genus of marine Sponges.

Forms a tliin semitransparent gelatinous
amber crust on rocks and shells, with indi-
stinct oscula and pores.

H. Dujardinii. The only species.

BiBL. Johnston, Br. Sponges ; Gosse,
Mar. Zuol. i. 0 ; Bowerbank, Br. Spony. ii.
224.

HALIS'ERIS, Tozzetti. — A genus of
Dictyotacea3 (Fucoid Alg*), containing one
British species, with a brownish olive,
sometimes forked frond with a midrib, from
4" to 1' high, having a very powerful otteu-
sive smell when fresh. The fructification
is produced in sori, arranged in lines on
each side of the midrib, or scattered, con-
taining large spores.

BiBL. Harvey, Mar. Akj. 36, pi. 6 B.

HALOCYTRIS, Dana.— A marine Os-
tracode, with very tliin, subquadrate, saddle-
shaped valves, beaked in front at the upper
angle. The closely allied Conchfscia, Dana,
has longer and subrectangular valves. Both
are related to Cypridina, and have two
pairs of feet, weak upper antennae, distinct
mandibles, large frontal tentacle, and no
eyes.

Living in the Atlantic and Mediterranean.

BiBL. Dana, E.vpL Exped., Crust. 1.301 ;
Bradv, Linn. Tr. xxvi. 409.

HALTE'RIA, Duj.— A genus of Infu-
soria, family Halterina.

Char. Body almost spherical or top-
shaped, with an anterior circle of cilia, and
a peripheral row of longer slender setae,
which by sudden contraction produce a
leaping motion. Freshwater.

H. yrandineUa=Trichi)dina yrandindln,
Ehr. (PI. oO. hgs. 11, 12) ; greatest breadth,
1-850".

H. volvo.v ; like II. yrandinella, but with
a second peripheral row of shorter and
closer cilia. 3 other species.

Stein points out the resemblance of this
animalcule to the swarm-germs of an ^4c«-
neta foimd upon Cyclops.

BiBL. Dujardiu, Inf. 414; Stein, Inf.;
CI. ct Each. Inf 369;" Kent, Inf 631.

HALTERl'NA, CI. & Each.— A family
of Peritrichous Infusoria.

Ci'iur. Free, globose or flask-shaped, with

an anterior circle of cilia, and sometimes a
peripheral row of longer setae, which by
their sudden contraction produce a leaping
motion.

Gen. : Halteria, with both cilia and setje ;
Strombidium, -with, cilia only; Mesodinium,
with a proboscis and setae ; Acarella, with
cilia and a carapace ; Arachnidkini, with
stout teutacle-hke cilia; and Uidinium,
with an anterior and posterior circle of
cilia.

HAL'TICA, 111.— A genus of Coleopte-
rous Insects ; fam. Galerucidae.

H. nemorum, the " turnip-fly." Oblong-
ovate, black ; elytra greenish black, with a
broad uninterrupted sulphm--yeUow streak,
not reaching the apex. Movement jump-
ing.

BiBL. Stephens, Brit. Coleopt. 291.

HALYME'XIA, Ag.— A genus of Cry-
ptonemiaceae (Florideoiis Algaj), containing
one British species, found on the southern
shores. It is a somewhat palmate, mem-
branous, rose-coloured sea-Aveed, usually
from 0 to 12" long, composed of a double
membrane, the layers being separated by a
loose network of jointed filaments. The
fructification consists of faveUidia buried in
the frond, attached to the inner surface of
the membranous laminae, scattered all over
the frond, appearing to the naked e}'e like
red dots.

BiBL. Harvev, Brit. Aly. 148, pi. 19 D.

HAPAEOSI'PHON, Nag.— A genus of
Oscillatoriaceae. Filaments branched, formed
of a t-ingle row of cells, \A\h. delicate co-
loured, indistinctly lamellar sheaths.

Four species; on freshwater plants.
(Rabenhorst, Fl. Alg. 283.)

HAPLA'RIA, Link. See Botrytis
grisea.

HAPLOMIT'RIUM, Nees.— A genus of
Jungermannieae (leafy Hepaticae), contain-
ing one British species, H. (Jiingermannia)
Hookeri, an Alpine plant, which lias been
carefully studied by Gottsche. It is re-
markable for having leaves (without amphi-
gastria) inserted on all sides of the stem.
The terminal capsule emerges at length
from a large oblong fleshy epigone (fig. 328).
The antheridia (fig. .323) occur in the axils
of. the leaves; they. have a double coat, the
interior of whicli consists of reniform cells
(fig. 322), which become isolated and more
or less dissolved. The spermatozoids, pro-
duced in minute vesicles (fig. 324), resemble
those of the Mosses.

HAPLOPHRACtIUM. [ 383 ]

HELICOSPORIUM.

Fig. 312.

Btbl. Hooker, Erit. Junrjermannirp, pi.
54 ; Ekart, <S'////. Jim(/. pi. tijz;. 05 ; Eudliclier,
Gen. Plant. No. 474-3 ; Gottsclie, Nova
Acta, XX. 2G"), pis. 13-20.

HAPLOPHRAG'MIUM, Reuss. — A
sandy Lituoliue Foraminifer, either nauti-
loid or crozier-shaped, with simple or coin-
pound aperture and undivided chambers.
Recent and fossil.

BiBL. Reuss, Sitzum/ffb. Ak. Wien, xliv.
381 ; Brady, Mic. Jn. li. s. xix. 29.

HAPLdSTI'CHE, Reuss. See Lixu-

OLA.

PIAPLOT'RICHUM,
Link. — A genus of 3Iu-
cediues (Hyphomycetous
Fungi), intermediate in
structure between Bo-
tn/tis and Asperf/illus.
The spores are developed
from a capitate cell
terminating the septate
erect fertile filaments
(tig. 312).

BiBL. Corda, Ic. Funn. • , , . ^
Nees Sust Pilze nl 4 . 3^?'°*"''^"™ '•o^''««>-
Fries, dm. Ve,/et. m. Magn. 200 chams.

HLIRPAC'TICUS. See Arpacticus.

HARPIRHYN'CHUS, Meg.— A genus
of Trombidina (Acarina).

H. nidulans, in the dilated feather-follicles
of the lark and green-finch, (Megnin, Paras.
243, fig.).

HAR'TEA, Wright.— A genus of Alcy-
onidiidse.

Polype solitary ; body cylindrical, fixed
at the base ; tentacles 8, knobbed at their
base ; basal portion of body thickly studded
with small star-shaped spicula; base and
body of tentacles with long dendritic spi-
cula ; mouth centi'al, with 2 lips ; somatic
chambers 8.

H. elegans. Height 3-4". White, br>se
dark. West coast of Ireland.

BiBL. E. S. Wright, Qu. Mic. Jn. 1865,
T. 213 (pi.).

HARVEST-BUG. Trombidixjm au-
tmnnale.

HASSALLIA, Berk. See Sirosiphox.

HASTERIGERI'NA, Thomson. — De-
scribed by Brady as scarcely separable from
Globiyerina (W. Thomson, Proc. P. S. xxiv.
534 ; H. Brady, Mic. Jn. 3, xix. 79).

HAUERI'NA, D'Orb. — One of the
Miliolidce, growing on one plane, subdis-
coidal, and characterized by a cribriform
aperture.

M. cotnjjressa (PI. 23. fig. 8). Fossil in the

Tertiary beds ; living in tropical sens ; rare
on the Jh'itish coast.

BiBL. Carpenter. Tntrod. For. 81.

IIAUSTO'RIA.— A term applied to cer-
tain short processes springing from the basal
fibres of the hyphtie of moidds, while travers-
ing the intercellular passages of the host-
plants ; they are often expanded at the ends.
They penetrate the parenchymatous cell-^, and
absorb their contents. They may be readily
studied in Ci/stopus.

BiBL. Brefekl, Schiinmclpilze ; De Bary,
Beitriif/c ; Sachs, Bot. 279 (figs.).

HAVERSIAN CANALS. See Bone.

HEART.— The muscular fibres of the
heart present certain pecuharities. The
primitive bundles are more slender than
usual ; they frequently anastomose, and
contain normally a few minute granules of
fat : the transverse striae are also often in-
distinct. In disease the fatty matter is often
extremely abundant (PI. 38. fig. 14 a), and
the strife are more or less obliterated.

BiBL. KoUiker, Mik. An. ii. ; Forster,
Path. An. ; Wedl, Path. Hist. ; Quain,
Med. CMr. Tr. 33 ; Rokitansky, Path. An.

HEDR^OPHY'SA, Kt. = sessile Bicos-
oeca. One sp., Jersey. (Kent, Infus. 274).

HEDWIGTA, Hook.— A geniis of Mos-
ses. See Zygodon.

HEIBER'GIA, Grev.— A genus of Dia-
tomaceae.

Char. Fr. compressed, quadrilateral, cel-
lulate, with a punctate surface of the angles,
where they probably cohere : valves with
one longitudinal and several transverse
costae, the longitudinal one terminating at
each end in a blank space.

A. Barbadensis (PI. 52. fig. 4). Barba-
does deposit.

BiBL. Grev. Mic. Trans. 1865, v. 100.

HELICO'MA, Corda.— A genus of De-
matlei (Hyphomycetous Fungi), with the
spores curled into a spiral. Berkeley
considers the distinction between Helieoma
and Helicosporium scarcely tenable, and
Fries includes Helieoma Midleri, Corda,
under Helicosporium. This plant has been
found on dead wood in this comitry.

BiBii. Corda, Ic. Fung. i. pi. 4. fig. 219;
Berkeley and Broome, Ann. N. H. 1851,
vii. 98 ; Fries, Sum. Veget. 500.

liELICOSPO'RIUM, Nees.— A genus of
Dematiei (Hyphomycetous Fungi), growing
on decayed wood, nearly related to Heli-
eoma and Helicotrichum, Helieoma and
Helicosporium are described as having erect
fertile filaments, Helicotrichum creeping

HELICOSTEGIA.

[ 384 ] HELMINTIIOSPORIUM.

Helicosporium pid-
vinatuni.

Magn. 200 diams.

branched filaments ; but Fig. 313.
the distinctions are ob-
scui'e, as also those be-
tween Helicoma and Heh-
cusporium, the first of
which should have the
sjiirals closed, the latter
open. Fries and Berkeley
both include Helicotri-
chiim WM^^ixHelicosporium.
British species :

H. puhinatum, Fr. (fig.
313 ). Forming a blackish
or olive pulvinate stratum
over v\Ood, with slender
branched filaments, bear-
ing yellowish-green strings
of sporidia coiled up into a spiral of about
three turns, very fugacious {Ilclicofrichuin
pulvinatum, JSees).

If. vegetum, Fr. Widely pulvinate-eft'used,
subolivaceous, at length black; fertile fila-
ments erect, stifr, subrdate ; spores coiled
into a ring, .j-septate, greyish green.

BiBL. Berk. Hook. Br. F/.'yvI ii. pt. 2.
335 ; A7m. N. H. 1850, vi. 434 ; vii. !)8 ;
Fries, Sj/d. Myc. iii. 353 ; Sum. Veg. 500 ;
Corda, Sturm, DeutscU. Flora., 3 ser. ii. pis.
15 & 10 ; Nees, Xova Acta, ix. 246, pi. 5.
15 ; Syst. Miicol. QS, fig. 09.
'HELICOSTE'GIA.— An order of Fora-
minifera, according to U'Orbigny's system,
comprising those coiled spirally on a single
axis. This feature, however, is common to
several genera which have distinct characters
of structure and habit, and has ceased to be
regarded as tvpical.

IIELICOS'TOMA, Cohn.— A genus of
Holotrichous Infusoria = ^?/ss?</« with the
pharynx hooked at the end. II. oblonga ; in
salt water ; 1. 1-125". (Kent, Infiis. 501).

HELlCOT'IlICnUM, Nees. See Heli-
cosporium.

IlELIOPEL'TA, Ehr.
tomacese.

Cltar. Frustules single (?) ; valves cir-
cular, with imperfect radiating septa, the
alternate intermediate portions of the valve
being depressed; markings absent in the
centre, but as many large submarginal
apertures (?) present as there are rays, and
numerous erect opposite submarginal spines
on each side. The spines coimect the pairs
of young frustules.

//. metii. Frustules with six septa and
rays,threeof the intervals raised and coarsely
cellular, the alternate ones impri'sscd with

%•

A genus of Dia-

fine

decussating linos.

the limb of the ra-

diate margin broad ; marginal spines in the
middle of each cellular interval one or three,
in the others two or four ; umbilical star
slightly angidar; diameter 1-370". Ber-
muda.

//. Leeuwenhoeckii, PI. 25. fig. 4. Three
other species, with a difierent number of
rays.

The difierent appearances of the markings
upon the elevated and depressed portions of
the. valves evidently arise from the existence
of the ordinary depressions seen uatui'ally by
oblique and direct light.

BiBL. Ehrenberg, Berl. Ber. 1844, 262 ;
Greville, 31ic. Tr. 1866, vi. 5 {new sp.).

IIELMIN'THOSPO TIIUM, Link. — A
genus of Dematiei (Hyphomycetous Fungi),
growing on rotten wood &c., of which nu-
merous species are found in Britain. Tulasne
regards this genus as consisting of stylo-
sporous forms of Splueriacei. Currey refers
to this genus Corda's Dacfglium (Dendry-
phium) fianosum. The mycelium is often
somewhat gelatinous or indistinct ; on it
arise (often aggregated) erect, rigid, septate
filaments (Jjbres), on the summits of which
stand large, often club-shaped sejDtale spores.
liritish species :

//. macrocarpum, Greville {Cn/pf. Fl. pi.
148. fig. 1).

H. subulatum, Nees {Xova Acta. ix. pi. 5.
fig. 13).

H. Clavariarmn, Desmazieres {Ann. Sc,
Nat. 2 ser. ii. pi. 2. fig. 2).

H. vehitinum, Link (Grev. Crypt. Fl.
pi. 148. fig. 2).

H. fusisporium, Berk. {Br. Flora, vol. ii.
part 2. 336).

H namtm, Nees {Nora Acta, ix. pi. 5.
fig. 13 B; Syste7n. fig. 65).

H. simjAex, Kunze (Nees, /. c. fig. 11).

H. Tilice, Fr. (Berkeley, Ann. N. H. vi.
pi. 13. fig. 18).

H. foUiculatum, Corda (7c. Funq. i. pi. 3
fig. 180).

H. ohovatitm, Berk. {Ann. N. II. \\. pi. 13,
fig. 19) ; on old wet planks.

//. delicatulum, Berk. (/. c. fig. 20) ; on
stems of Umbellifera3.

//. Smithii, Berk, and Broome {Ann. N, II.
1851, vii. pi. 5. fig. 5).

H. turhinatum, Berk, and Br. (I. c. fig. 6).

II. Iiousselia7ium, Mojitagne {^Ann. Sc.
Nat. 3 ser. xii. 300).

H. stktitiim, Berk, and Br. {Ann. N. II.
1854, xiii. pi. 15. fig. 10)!

BiBL. Berkeley, Br. Fl. iii. pt. 2, 33(5 ;
Fries, Syst. iii. 354, and Sam. J'eyet. 5C0

IlELMINTITOSTACIIYS.

[ 385

HEMP.

(1849); Ciirrov. Qu. Mic. Jn. v. 115: Tulasne,
Ann. >SV\ Nat.' A ser. v. lUO.

HELM INTHOS'TACII YS, Kaulf— A
geuiis of Ophioglussaceous Ferus, distin-
guished by the complex spikes bearing
crested sporanges.

Fig. 314.

Fig. 315.

Helminthostachys zeylanica.

Fiij. 314. Fragment of a spiie with sporanges. Mag-
nified 10 diains.
Pig. 31.5. A portion stUl more magnified (20 diams.).

HELVEL'LA, L. — The typical genus of
Helvellacei.

Several species occur in this country,
among.st which II. lacunosa and H. crispa
are esculent.

BiBL. Fr. Syst. Myc. vol. ii. 13 ; Berk.
Outl. 358 : Hooker, 8yn. 447.

HELYELLA CEI.^A family of Asco-
mycetous Fungi, comprised in Discomycetes,
approaching the Hymenomycetes in outward
form, but distinguished at once by their
fructification. See Ascomycetes, IIel-
TEULA, Spathulaeia, Leotium, Stictei,
Peopolis.

HEMELYT'RA.— The anterior pair of
wings of the Heteropterous division of the
Hemiptera. See Insects.

HEMEPtO'BIUS, [Linn.— A genus of
Neuropterous Insects.

Hemerobhis (^Chrysojjd) peria, one of the
lace-winged flies, has very thin, transparent,
and beautifully netted iridescent wings, in
which the circulation can be well observed;
the wings also exhibit well the tracheae in
the veins. The larva feeds upon Aphides.

BiBL. Westwood, Intr. ; Bowerbank,
Entom. May. iv.

HEMIAU'LUS, Ehr.— A genus of Dia-
tomacese.

Char. Frustules single, compressed, sub-
quadrate, with two tubular processes on each
side^ the ends of those (the shorter) on one

side being open, the others closed ; not con-
stricted at the sides.

H. antarcttcus (PI. 25. fig. 3).

BiBL. Ehrenberg, licrl. Bet: 1S44, 109 ;
Greville, Ann. N. IL xvi. 5 ; id. Mic. Tr.
18(35, 20, 52, 101.

HEMIDIN'IUM, Stein.— A genus of
Cilio-flagellate Infusoria: free, flagellum
single ; a fringe of cilia in a groove exten-
ding halfway round the body. II. na-
sufum, yellow ; freshwater. (Kent, Infus.
442.)

HEMIDIS'CUS, Wall. — A genus of
Diatomacese.

C7ta)\ Fr. free ; valves arcuate, with a
median marginal inf eiior nodule ; areolation
hexagonal, radiate.

//. cuneiformis. From Salpcs, Bay of
Bengal and Indian Ocean.

BiBL. \Vallich, Mic. Tr. 18G0, liii. 42

(%.).

IIEMILEI'A, Berk.— A genus of Ure-
dineas (Hypodermons Fungi), characterized
by the meniscoid spores, which are smooth
within, but strongly granulated without. H.
vastatri.v, the Coffee-fungus, is extremely
destructive to the CoHee-plants, forming
orange-brown spots upon the leaves. One or
two other Rubiacese are attacked by a
distinct species. In germination, a form of
Feniciliium has often been developed, but
this is probably accidental.

BiBL. Berk. & Br., Jn. Zinn. Soc. xiv. 93 ;
Dyer, Qn. 3Iic. Jn. 1880, xx. 119 (fiR's.) ;
Abbay, Jn. Linn. Soc. xvii. 176; Ward,
3Jic. Jn. xxii. (fiofs.).

HEMIOXI'Tl'S, Linn. — A genus of
Grammitideaj (Polypodiaceous Ferns), with
a very elegant reticulated arrangement of
the sori.

Eight species ; exotic. (Hooker, Si/n. ML
398.)

HEMIOPH'RYA.— A genus of Acine-
tina (Kent, Inf.).

IIEMIP'TEPtA.— An order of Insects.

HEMIP'TYCIiUS, Ehr. See Arach.

NOIDISCXIS.

PIEMITE'LIA; Presl.— A genus of Cya-
thpeous Ferns. Exotic. (Hook. Syn. 27.)

HEMIZOS 'TER, Ehr.— (Ehrenberg, Ber.
Berl. Ak. 1844, 199).

HEMP. — The ordinary name of the fibre
of Cannahis saliva, consisting of the liber-
fibres of this plant (PI. 28.''fig. 6). It is
applied to some other substances used for
the same purposes, e. ff. Manilla hemp (the
fibre of Musa) &c. See Textiee eibhes
and LiBEK,

2c

HENDERSONIA.

[ 38G ]

HEPATICJE,

IIENDERSO'NIA, Berkeley {Sporoca-
chi^s, Corda, in part). — A genus of Spliaero-
netnei (Stylosporous Fungi), interesting as
having furnished one of the earliest dis-
covered examples of two forms of fructifica-
tion, leading to the aholitionof the distinction
between Coniomycetous and Ascomycetous
Fungi (CONIOMYCETES). Berkeley has
seen two conditions of spores in H. mvta-
bilis, and states that Fries informs him of

Fig. 316.

Hendersonia.

Spores on the perithecimn.

Magnified 200 diams.

the ohservation of asci and septate naked
spores (sti/loxpores) conjointly in Hendersonia
Si/rinc/ce. Several British species have been
described. They form dark spots or patches
on the stems of herbs or twigs of trees, — the
dark matrix having a iJerithecium excavated
in it, lined by a gelatinous stratum, on which
stand stalked fusiform septate spores (fig.
31G).

H. ehqans, Berk. (PI. 27. fig. 11) {Ann.
N. 11. 1840, vi. pi. 11. fig. 9). On the culms
of reeds.

//. macrospora, Berk, and Broome (/. c.
2nd sei". v. 373). On dead twigs of Phi-
ladelphus.

IL arcus, Berk, and Br. (/. c). On Box
twipfs.

H. mutah'b's, Berk, and Br. (/. c.)
dead twigs of Plane.

II. poh/cj/sfis, Berk, and Br. (/. c.)
dead twigs of Birch.

//. macropus, Berk, and Br. (/. c.)
dead leaves of Care.v.

H. hjphoideanim, Desmazieres (Ann. Sc.
Kelt. 2) ser.xi. 344). On dead stems of Typha,
&c.

If. Stephcnsii, Berk, and Br. {Ann. N.
H. 2 ser. viii. Oo). On dead stems of Ptcris
aquilino.

II fihriscta, Berk. {Iloolcers Jn. But. iv.
43). On birch planks.

On
On
On

BrBL. Berkeley, and Berk, and Broome,
Ann. N. H. iv. 4-3 ; Hooker's Jn. of Bot. iii.
319 ; Fries, Sum. Veg. 41G ; Tulasne, Ann.
Sc. Kaf. 4 ser. v. 115.

HEPAT'IO.E.— An order of Muscales
(Cryptogamous Plants), consisting of plants
of small size, varying much in structure,
inhabiting damp spots on the ground, rocks,
or trees, or floating on water.

The vegetative structure of the lowest
forms consists simply of a patch of gi-een
membrane, spreading over the groimd,
composed of a single {Anthoceros l<evis) or
double {Sp/iarocarjms terrestris) layer of
cells containing chorophj-ll. In Mar'chantia
(see Marchaxtia) there is an advance ; the
frond not only exhibits more definitely cha-
racterized lobes, but also a considerable
thiclmess, and a complexity of internal
structure, since it possesses an epidermis
mvesting both surfaces, and containing
stomata on the upper (see Stojiata). The
lower epidermis is also provided with nu-
merous radical hairs (see Hairs and Spiral
Structures). Fimhriaria (fig. 318) and

Fig. 317.

Fig. 318.

Fimbriaria fragrans.

Fig. 317. Lobe of a frond. Nat. size.
Fig. 318. Section of frond, showing two immersed
antheridia. Magnified 40 diams.

Lnntdaria (fig. 319), &c., likewise possess
thick cellular fronds. In Ricciu the frond
also presents a reticulated upper face pro-
vided with stomata ; but the form of the
entire frond is usually elongated and bifur-
cated, and a slight groove runs along the
middle line, almost like a mid-nerve. This
central line exhibits a diftereuce in the in-
ternal cellular structure, since it is composed
of elongated cells, while the surrounding
gr^en substance is . composed of spherical
cells, sucli as constitute the entire ma,'S
enclosed between the upper and lower epi-
dermis of the frond of Marchantia. Ihe
grooA e on the upper face (of liiccia) con-e-
sponds to a rib on the lower face, from
which arise most of the radical filaments.

HEPATIC^.

[ 387 ]

HEPATIC^.

while thev ave scattered indiscriminately
over the lower face of Marchantia ; and from
this line also arise the little bodies resem-
bling minute leaves, called amphi(/astria. If
we suppose the frond of liiccia elongated
and the mid-nerve more strongly marked,
we have the likeness of Bhfttia LyeUi (tig.
62, p. 100) ; while ifthis latter were notched
down to the rib at intervals along each side,
we should have the stem with two parallel
rows of leaves, as in the Jungermanniese.

Fig. 319.

Lunularia vulgaris.
A frond ia fruit. Nat. size.

The line of insertion of the leaves is
seldom exactly parallel with the axis of the
plant, and very rarely at right angles. In
most cases it is more or less oblique, and
the obliquity is in reverse direction at the
two sides of the stem, so that the lines of
insertion of two succeeding leaves would
meet, if prolonged across the stem, in the
formofa V (fig. 320).

The leaves are very frequently imbricated,
and they overlap in two ways : either each
leaf covers with its lower edge a little of the
leaf below it, or each leaf overlaps a little
of the base of the leaf above it. In the first
case, the leaves are called succubous (tig.
320), in the second inciibous (fig. 321). The
leaves vary much in form, and are often
deeply toothed or bilobed, and form exceed-
ingly elegant objects under the microscope.
The leaves are accompanied in many cases,
chiefly in the Jungermannieae, by stipule-
like leaflets, called amphi(jastria, situated at
the imderside of the stem.

These plants are reproduced by dust-like
grains called spores, by minute cellular no-
dules called (/emmce, and by innovations, i. e.
new lobes growing out from the margins of
the old fi'onds, or buds m the axils of leaveS;

or on confervoid branches set out from the
stem.

The gemmcB oi Marchantia poly morpha are
produced in elegant membranous cups, with
a toothed margin, growing on the upper
surface of the frond, especially in very damp
and imperfectly lighted situations ; they are
little cellular nodules at first attached by a
stalk, and at a certain period fall off and
grow up into a new frond. (See Makchan-

TIA.)

Fig. 320.

Fig. 321.

Fig. 020. Eadula complauata. Magn. 5 diams.
Fig. 321. Plagiocliila, undulata. Magu. 5 diams.

The spores are produced in sporanges or
capsules, the formation of which is preceded
by special anatomical and physiological
phenomena demonstrating the existence of
distinct sexes in these plants. The organs
which represent the anthers of flowering
plants are called antheridia ; those which
represent the ovules, and produce the spore-
cases, are called archcyonia or pisfi/lidia.
The antheridia are small globular or oval
bodies, more or less stalked, which in the
JungermaunieEe are composed of a double
layer of cells forming a membranous sac,
which, when ripe, bursts and dischargta
numerous minute globular cellules, each of
which again bursts and discharges an ex-
tremely small filament, which moves about
actively in water (figs. 322 & 324). These
organs mostly occur in the same situations
as the archegonia ; and in some of the fron-
dose forms, such as Anthoceros, Hiccia,
Fimbriaria (fig. 318), &c., they are im-
bedded in the substance of the frond ; in
others, as in Marchantia, they are immersed
in the upper part of special male stalked

2c2

HEPATIC^.

[ 388 ]

HEPATIC-E.

receptacles (see Mabchantia) ; iu fhe leafy
forms they are free in the axils of the
leaves (fig. 323).

Fig. 322.

Fig. 323.

Fig. 324.

Haplomilrium Hookeri.

Fig. 322. Axillary antheridia. INIagn. 30 diams.

Fig. 323. Fragment of wall of antheridia; the reni-
form loose cells belong to the inner layer. Magn. SOU
diams.

Fig. 324. Bpermatozoids from ditto. Magn. 200 diams.

Fig-. 325.

Fio-. 327.

Marchantia polymorpha.

Archegonia in yarious stages.

Magnified 100 diameters.

The archegonia or i^^^tilUclia are likewise
developed in various places, indicated liere-
after in th(3 tabular view of tlie lauiilies.
They consist of a kind of tlask-sliaped cellu-
lar case (figs. 320 to 327), enclosinir at first
a single cell {e^nhryonnl cell), which subse-
quently grows into a sporange, apparently
after one or more of tlie spiral filaments of
the antherids have come in contact with it,
hy passing into the neck of the fiask-shaped
sac {epiyone). The emhr^-onid cell becomes

increased by cell-division into a globular
cellidar mass, which acquires various forms
in the different genera and families. The
epigone enlarges for a long time with the
growing capsule, completely enclosing it
(fig. 328) ; but after a time the latter bursts

Fig. 328.

HaplomitriuDi Hookeri.

Young sporange enclosed in the epigone.

Magnified 20 diameters.

through the top of the epu/one, which thus
forms a kind of sheath rouud the base of the
sporange or its stalk, and is called the vagi-
nule. The epigone may tear irregularly, so
as to form an irregidar vagmide or cah/x, or
regularly, so as to present a circle of teeth ;
or it maj' be slit horizontally in a circle, and
half of it carried up by the sporange, which
it thus surmounts as a hood or cah/ptra.
This epigone is sometimes surrounded by
another envelope called the j^'^i'tgone. This
originates at a later period and in a diflferent
way, since it gradually springs up as a cir-
cular sheath around the base of the epigone,
and by continued growth comes to surround
it as a kind of cup, like the corolla of a
flower (fig. 320). In Marchantia, only one
archegone is found in each perigone ; the
perigones of Jungermannieae always enclose
several, but only one is developed into a
sporange. In some kinds, as Sarcoscgphits,
there are always several archegones in a
perigone, and two or three produce spo-
ranges. Sometimes the archegones, with or
without perigones, are solitary : more fre-
quently they are in groups. Whether soli-
tary or grouped, thej' may have a further
envelope composed of slightly modified
leaves, free or confiuent together : these are
the perich<^tial leaves, and constitute the
perichcete. When both pericha-ie and peri-
gone exist, it is easy to determine which is
which; but when only one exists, the history
of development alone gives the key j the

HEPATIC.^.

[ 389 ]

HEPATIC^.

interestiug

periclioete is always developed before the
aivbegones it encloses, while the perigone,
as already stated, grows up round the arche-
gone during its development into a sporange,
being absent at the time of the first a])pear-
ance of that organ. In fig. 320 the base of
the pedicel is seen to rise out of a toothed
vaginule ( cah/x or epigone), which is enclosed
in a tubular perigone, outside of which are
two bilobed pericha^tial leaves.

The sponuige developed from the embry-
onal cell of the archegone varies much in
its perfect condition. In Jungermanniese it
is mostly an oval body borne on the extre-
mity of a delicate thread-like stalk spring-
ing out of the vaginule (fig. 320). The oval
body splits down from the summit, when
ripe, into four valves, which spread open
more or less in the form of a cross (figs.
320-1 ). or bursts irregularly. The cells of
the valves exhibit very elegant spiral-
fibrous structure, like that of the waUs of
anthers (see Spiral Strttctfees). This
kind of sporange discharges minute spores
(see Spores) and elaters, slender tubular
cells containing a spiral filament (PI. 40.
fig. 38), both forming very
microscopic objects.

In the diftereut fi'ondose forms the spo-
ranges present very varied conditions. The
archegones of A>iTHOCEEOS send up a fili-
form sporange, which is two-valved and
contains a columella (fig. 24, p. 58). In
Targioxia and some others the capsule is
almost sessile, and bursts irregularly. In
RicciA, where the archegones are imbedded
in the frond, the sporange is a sessile globose
body, with the calyptra adherent, never
bursting regularly, but emitting the spores
by decay. In SpHiEROCARPUs, also, the
calyptra is permanent as a cellular sac, in-
side of which the sporange ripens into an
indehiscent globular body, emitting the
spores only by decay. In Marchantia, Fe-
gatella, Lunularia, Grimaldia, &c., the arche-
gones are produced on fleshy receptacles
elevated upon stalks, and the sporanges
are formed on the underside of these
receptacles (fig. 219. p. 317, figs. 3-30, 33.3,
335), which are of varied forms, &c. The
sporanges on these either bui'st by valves
(fig. 331), or by circumscissile dehiscence
throw off" a lid, as in Fimhriaria (fig. 335).

The frondose forms do not all produce
elaters, and have not all the spii'al fibres in
tbe cells of their walls. The exceptions
are the Ricciese ; and the elaters of Antho-
ceros are rudimentary. In Marchantia the

Fig. 329.

Fig. 330,

Fig. 331.

lunularia vulgaris.
Fig. 329. Section of a receptacle, unripe.
X ig. 330. More advanced sporange, emerged &om the

epigone.
Fig. 331. A burst sporange.

Magnified 20 diameters.
Fi£

>•. 332

Fig.

Grimaldia barbifrons.

Fig. 332. Fertile plant. Magn. 2 diams.

Fig. 333. Section of the receptacle, with an abortive
archegone on the left side, and a half-ripe sporange still
enclosed in the epigone on the right. Magn. 20 diams.

Fiff. 334.

Fig. 335.

Fimhriaria tenella.
EeceptacleB^with closed epigones.

Magn

Fig. 334.
10 diams.

Fig. 335. Two perigones, one with the epigone closed,
the other with the teeth of the epigone open, showing
the bursting sporange. Magn. 20 diams.

elaters are highly developed (PI. 40. figs.
36, 37), also the spiral tissue of tbe valves

HEPATIC^E,

L 390 ]

herp}=:tium.

of tlie capsules (PL 40. fig. 35). Taegionia
has branched elaters.

The spores mostly have a double coat, but
not always (e. g. Marchantia) ; they germi-
nate by protruding a pouch-like process,
■which becomes a filament, from which the
new fronds or leafy stems arise.

The peculiarities of the different groups
above referred to will be better understood
after reading the following characters.

Synopsis of the Families.

A. Vegetation frondose, i.e. leaf and stem
confounded.

ANTHOCFEOTEiE. The Vegetative por-
tion consists of a minute green membranous
or slightly fleshy body growing on damp
ground, not exhibiting any distinct mid-
nerve : it is at once known by its peculiar
fruits or sporanges, consisting of slender
stalk-lilie bodies springing up irregularh^
from the upper surface of the frond, which
forms little sheaths (rrt//^n^//^s) around their
bases. These stalk-like fruits burst when
ripe, splitting down the middle from the
tip, and display a central bristle-like column
(columeUa), to which adhere the minute
hair-like bodies (rudimentary elatersj which
are mingled with the spores.

]\L\E CHANTIES. The vegetative portion
is here also a succulent leaf-like expansion,
mostly exhibiting a more or less lobed
form, and without any conspicuous mid-
nerves in the lobes. The fruits are more
complicated structures than those of Antho-
ceroteae. From notches in the Inbed frond
arise slender stalks terminating at the top
in an expanded structure {i-eceptctcle), re-
pombliiig in some cases a conical cap, in
others a star with a number of thick rays
like the spokes of a wheel, &c. The spores
are formed in membranous sacs attached on
the imder surface of the cap or star-like
body, and they are occompfnn'ed hi/ elaters of
considerable size exhibiting highly deve-
loped spiral bands. JThe sporanges have no
columella, and burst at the tip with more or
less regular tooth-like valves.

Rict'iEiE. Vegetative portion an exceed-
ingly delicate cellular leaf-like structure,
more or less lobed, with an evident mid-
nerve. The sporanges are eitlier imbedded
in the substance of the frond, or only ele-
vated on a very short stalk, and surrounded
by a membranous sheath derived from the
upper surface of the frond. The sporanges
have rw columella and no elaters.

Pellie^. Vegetative portion a leaf-like
frond, mostly with an evident mid-nerve,
from %vhich arises the sporanges, consisting
of capsules, usually bursting by four valves,
more or less elevated on a thread-like stalk.
Sporange without a columella; spores ac-
companied by elaters.

B. "S^egetation foliaceous, i. e. leaves and
stem distinct.

JuxftERMAN^STE^T:. Vegetative portion a
thread-like stem clothed with green mem-
branous leaves more or less overlapping at
their bases. Sporanges springing from the
end of the stem, raised on more or less
evident stalks, bursting by four valves and
spreading in the form of a cross; spores
with elaters, which often adhere to the
valves of the sporange. The leafy stem of
Jungermanniefe is generally readily distin-
guishable from that of the Mosses by the
mode of insertion of the leaves, which pro-
duces a peculiar flattened arrangement.

BiBL. Hooker, Br. Jungermannife, 181G;
Bischoff; Xova Acta, xvii'. 909, pis. 67-71,
1835; EntivicM. d. Lehermoose, Bot. Zeit.
xi. 113, Ann. So. Nat. 3 ser. xx. 57; Lin-
denberg, Sgnops. Hepatic. 1814 ; Greenland,
Ann. Sc. Nat. 4 ser. i. 5 ; Hofmeister, Vergl.
Uniers. iib. Kryptog. 1851 ; Gottsche, Bot.
Zeit., Suppl. vi. 1858; Du Mortier, Hepat.
Europ. 1874; Camngton, Hepat. 1876;
Leitgeb, Leherm. 1879 ; Husnot, Hep. Gall.
1881.

HERCOTHE'CA, Ehr.— A genus of fos-
sil Diatomaceae. '

//. ma^nmillaris (PI. 18. fig. 31), the only
British species; diameter 1-810". Bermuda.

BiBL. Ehrenberg, Ber. d. Berl. Ak. 1844,
262 ; Kiitzing, <S),. Ah). 27.

IIERMAN'NIA, Xicolet.— A genus of
Oribatea (Acarina). Cephalothorax without
ribs, soldered to the abdomen ; tarsi with
one claw. In moss. (Murray, Ec. Ent. 221,
figs. ; Michael, Jn. Mic. Soc. 1880, 192.)

HERPE'TIUM, Nees.— A genus of Jun-
germanniefe (leafy Ilepaticfe), distinguished
by the incubous biL bed leaves not being
folded together, and by tlie obtusely three-
angled perigone. Two Brit, species :

H. reptans{Lepiduzia, Dumortier). Leaves
squarish, acutely two- or four-toothed at
the end. "Woods and shady places. Jung,
reptans, Hook. Br. Jung. pi. 75.

//. trilohutum {Ma^tigobrgum, Nees).
Leaves ovate, three-toothed at the summit.
ISIoist alpiue spots. J. triluhatum, Hook.
Br. Jung. pi. 70.

HERPETOMONAS.

[ 391 ]

HETEROSTOMELLA.

BiBL. Hooker, Br. Jung. I. c. ; Eud-
liclit'i', Oen riant, uos. 472-'J ; Ekart, Syn.
Jum/. pi. •i. iiu's. ^1, '2'2.

liEKPJ-yrO'MONAS, Kt.— A geuu3 of
Flagellate Ini'usoria.

Char. Iree, elongate or vermicular,
highly llexible ; iiagelluin single.

H. intiscce, in the intestine of the house-fly.
H. Lewisi (PI. 53. fig. 18), in the blood
of Indian rats ; perhaps also in the blood
of the lield-mouse and mole; 1. 1-1500".
(Kent, Infus. 245 ; Lewis, Qu. Mic. Jn.
1870.)

HETEROCORDY'LE, Allm.— A genus
of llydroid Zoophj-tes, fam. Atractylidas.

H. Conyheurei. Ou old shells ; marine.
Ireland.

BiBL. Allman, Ann. N. H. 1864, xiv.
59 : Hiucks, Brit. Zooph. 107.

ilETERODES'jlUS, Brady.— A genus
of recent Ostracode Entomostraca, family
Cypridinida; ; subglobose, with the hinges
of the valves developed into large processes
at the dorsal angles.

H. Adamsii. Sea of Japan.

BiBL. Bradv, Zool. Trans, v. p. 387.

HETEKU1)1C'TY0X, Grev.— A genus
of Biatomaceas.

Char. Fr. free, disciform ; disk with
radiate or scattered puncta in the middle
portion, and a ring of large intra-margiual
cell ides.

//. Rylandsianum and H. splendidmn.
Barbadoes deposit.

BiBL. Grev. Mic. Tr. 1863, iii. 66 (fig.).

IIETEROMAS'TIX, Clk.— A genus of
Cilio-flagellate Infusoria ; corresponding to
a Euylena with two anterior flagella, one
trailing; and an anterior oral fringe of cilia.

II. pruteiformis, in fresh water. (James-
Clark, Mein. Bost. Soc. N. H. 1868 ; Kent,
Infus. 403.)

"HETERO'MITA, Duj.— A genus of Fla-
gellate Infusoria.

Char. Body globular, ovoid, or oblong,
with two filaments arising from the same
point in front — one, more delicate, and with
an imdulatory motion, causing' progression ;
the other thicker, and floating freely be-
hind, or adhering here and there to the
slide, so as to produce by its contraction
sudden motion backwards.

Distinguished from Anisonema and Ilete-
ronema by the absence of a tegument, shown
bv the glutinous appearance of the body,
the facility with which it adheres to other
objects and becomes drawn out, and the
presence iaterually of certaiu corpuscles

which can only have entered by vacuola
formed on tbe surface.

Found in both fresh and salt water, and
in lish-maceratious,

H. ovata=Bodo graudis, E. (PI. 30. fig.
18 a) ; among freshwater plants.

//. granulosa. Body globular, surface
granular; marine; length 1-2300".

H. angusta. Body lanceolate, .slightly
sigmoid; freshwater; length 1-980".

Other species.

BiBL. Dujardiu, ////(W. 297; Kent, iw/ws.
290.

HETERONE'MA, Duj.— A genus of
Flagellate Infusoria, of the family Euglenia.

Char. Form variable, oblong, irregularly
expanded posteriorly ; with a slender flagel-
liform filament, and a thicker trailing, re-
tracting filament ; tegument obliquely stri-
ated.

Differs from Heteromita in the presence
of a tegument, and from Anisonema in the
tegument being contractile.

H. marina (PL 31. fig. 17). Filaments
longer than the body; length 1-4300".

BiBL. Dujardin, Infus. 370; Kent, Inf.
430.

HETEROTHRYS, Archer.— A genus of
freshwater Rhizopoda. 2 species.

BiBL. Ai-cher, Qu. Mie. Jn. 1869, Lx. 267

HET'EROPUS, Newp. — A genus of
Acaviua.

H. ventricosus occurs in the nests of An-
thophora rettisa, living upon the larvae.
(Newport, Linn. Tr. 1850 ; Mm'ray, Ec,
Ent. 290, figs.)

HETEROSTEGI'NA, D'Orb.— A flat,
discoidal Nummuline Foraminifer, with
whorls rapidly increasing in breadth and
reticulated by the primary and secondary
septa of the narrow carved chambers and
their rectangular partitions. Living in tiie
Eastern Archipelago ; fossil in the Tertiary
beds, especially forming one stratum in the
island of Malta.

BiBL. Carpenter, Intr. For. 288 ; Jones,
Geol. Maq. ii. 151.

HETE'ROSTOMEL'LA, Reuss.— One of
the Textularian Foraminifera, in which the
chambers are at first set on alternately, but
not neatly, on either side of a straight axis,
and afterwards, gro"wing in a single row, as
in Bigenerina, not only open terminally, in-
stead of laterally, but have a tubular, and
even a lipped, aperture, such as we see in
Uvigerina. Shell often prickly. Fossil in
the Chalk of Europe and America.

HETEROTEICHUS.

[ 392 ]

HIMANTOPIIORUS.

BiBL. Eeuss, Sitz. Ak. Wien, Hi. ; Parker
and Joues, Ann. N. II. ser. 4. ix. 208.

HETEROT'RICHUS, Dounadieu. — A
genus of Acariua, faui. Ganiasea.

II. i7tcequarmatus. Hairs jointed, longer
tlian the body.

BiBL. Diiiiuadieu, Jn. de VAnat. 1876
(Mn. Mic. Jn. 1877, xvii. 28;5, fig.).

HP]WAR DIA, 1100]^. = Adiantum, pt.

HEXAM'ITA, Duj.— Agenus of Flagel-
late lufiis^oria.

C/uir. Body ohlong, rounded in front,
constricted and bifid or indented behind ;
four flagelliform filaments arising separately
from the anterior margin, the two posterior
lobes being prolonged into flexuous fila-
ments.

//. nndulosa (PI. 31. fig. 20). Oblong,
with three or four longitudinal rows of no-
dules ; motion vacillating ; length 1-1800".
In decomposing marsh-water.

H. injiida ; in decomposing infusion.^.

II. intrsthialis. Fusiform, prolonged into
a bilid tail ; length 1-2100". In the intes-
tines and peritoneal cavity of the Batrachia
and Tritons.

BiBL, Bujardin, hifits. 296 : Kent, Inf.

^ lilLDENBRAND'TIA, Zanardini. — A
genus of Nulliporous Corallinacea? (Flori-
deous AlgjB), containing one British species,
H. sanr/uinca, Kiitz. : common, in the form
of a bright or dark red membranous crvist,
at first circular, afterwards spreading irre-
gularly over smooth stones and pebbles.
Frond about 1-20" thick in the middle,
thinner toward the edges, and composed of
minute globose cells, partly vertical, partly
horizontal ; it is not stony. It has immersed
conceptacles, pierced by a pore (fig. 250,
p. 327), containing tetrasiwres and para-
physes.

One species occurs in alpine streams.

BiBi.. Harvey, Mar. Ah/. 110, pi. 14 C ;
rin/c. Brit. pl."2rj0 ; Kiitz". rhyc. Gen. pi.
78* fig. 5; Rabenhorst, Fl. Ah/', iii. 408.

Ill LUM. — This name is appHed to the
svnface of attachment of the funiculus of
seeds, which is seen as a kind of scar, more
or less distinct. Sometimes it coincides
with the clialaza or organic base of the
seed, sometimes, where a raplie exists, it is
near tlie micropvle. (See Ovule.)

III.MAKTITA'LIA, Eyngbye.— A gonus
of Fucacea) (Fucoid Algiie), remarka])le for
the peculiar forms of the frond and recep-
tacle, the latter consisting of a repeatedly
forked strap-sliaped cord from 2 to 10' long,

springing from the top-shaped frond, which
is about an inch high. The dark olive-green
thong-li]<e II. lorea is common on roclfy
sea-shores. The receptacle is pierced by
numerous pores leading to immersed con-
ceptacles resembling those of Fucus, con-
taining either jiavietal spore-sacs or antheri-
dia, the plants being ditecious. The centre
of the receptacle is filled with mucous
matter traversed by jointed filaments. The
antheridial sacs of IIi)n(tnfhcdia are double,
and contain spermatozuids of fiattened ovoid
or spherical forms, with an orange granule
and two cilia, like those of Pycnojyhycus
and Ilalidrys.

BiBL. Harvey, Mar. Ah/. 20, pi. 2 ]J ;
Thuret, Ann. Sc. Nat. 3 ser. xvi. 54 ; Gre-
ville, Ah/. Brit. pi. 3 ; Engl. Bot. pi. 569.

HIMANTID'IUM, Ehr.— A genus of
Diatomaceae, cohort Eunotiese.

Char. Frustules resembling those of Eu-
notia, connected by their sides into a fila-
ment ; strife transverse, parallel. Fresh-
water.

Iviitzing describes thii'teen species, some
of wliich are fossil ; Smith admits eight
British species, one doubtful.

II. /yectinale {Frax/ilaria pect., Ralfs) (PI.
16. fig. 36). Frustules in side view nar-
rowed at the curved and rounded ends ;
one side slightly raised and flat, the other
slightly excavated or flat; striae evident;
length" 1-180".

/3. Convex margin undulate or with two
indentations (fig. 3(5 h) = II. undulatum, Sm.
Ralfs remarks a difference of form between
the newly-forujing and the parent frustules,
the lateral margins of the former in fronl:
view being rounded (fig. 36 c).

//. arcus. Fr. rectangular ; valves linear-
arcuate, ends roundi'd, subrecurved ; striae
evident ; length 1-300 to 1-132".

BiBL. Ehrenberg, Berl. Ber. 1840 ; Kiit-
zino:, Bacill. 3(5 ; Sp. Ah/. 8 ; Ralfs, Ann.
N.H. xii. 107, xiii. 459;" Smith, Br. Uiat.
ii. 10.

llI3rANT0PH'0RUS,Fabricius.— A ge-
nus of Infusoria, of the fi^mily Euplota.

Char. Head not distinct from the body;
hooks numerous ; neither styles nor teeth
present.

Long curved hooks, almost in pairs, form
a broad band on the ventral surface, and are
the organs of locomotion ; also a row of cilia
extending from the mouth a considerable
distance backwards.

II. Charon (PI. 31. fig. 18, under view ;
fig. 19, side view). Body hyaline, plane,

IIIPPAEOIIIA.

[ 398 ]

HOLOPHRYA.

elliptical, anterior end somewhat obliquely
truncate ; cilia small. IkhiIvS sleuder and
loUiT. ^farine. Len-tli 1-180".

BiBL. Elirenberg, Infus. p. 37o.

IIIPPAK'CHIA, Fabr.— A genus of
Lepiiloptertuis Insects.

Vliar. ^Vings more or less rounded, mid-
dle longitudinal nerve of fore wings giving
off posteriorly four nerves ; antennfe with
an elongate, compressed and curved club ;
head small.

H. Janira, the meadow brown butterfly,
in which the wings are brown, and the
anterior pair exhibit a blackish-brown round
spot with a white eye or centre, is common
in meadows. The paler scales of the anterior
•wangs (PI. 1. fig. 9) were formerly used as
Test-objects.

BiBL. Westwood, Introd. and Br. Butter-
Jfics.

HIPPOCRE'PIA.— An order of Polyzoa.

Distinguished by the crescentic or horse-
shoe-shape of the tentacular disk, and the
presence of an epistome. Freshwater.

SynojJsis of the Families.

Cristatellidje. Polype-mass floating.

PLTJjiATELLiDiE. Polype-mass rooted,
unjointed.

The family Paludicellidfe, containing the
single genus PahidiceJla, is usually placed
here ; but it properly belongs to the lufun-
dibulata, as the tentacular disk is circidar
and entire, and the epistome absent.

See Polyzoa and Urnatella.

HIPPOCREPI'XA, Parker.— A Lituo-
line Foraminifer, characterized by the horse-
shoe-shape of the aperture, due to the pre-
sence of a tongue-like process, as in Vulvu-
lina. H. indivisa, from the Gulf of St.
Lawrence, is carrot-shaped.

BiBL. Parker, in Dawson, Canad. Nat.
1870.

HIPPOTH'OA, Lamx.— A genus of In-
fundibulate Cheilostomatous Polyzoa, of the
family Eucratiidae (Scrupariidas).

Distinguished by the confervoid, branch-
ed, creeping and adherent polyzoary, the
branches arising from the sides of the ellip-
tical cells, frequently anastomosing, and the
cells in one row.

II. catemdaria. Cells contiguous, orifices
oval. On shells in deep water.

H. divaricata. Cells remote, orifices round.

BiBL. Johnston, Br. Zorph. 291 ; Gosse,
Mar. Zool. 12 : Hincks, Polyzoa, 256.

HIPPUPtA'KLi, Busk.— A genus of

Ctenostomatous Polyzoa. (Hincks, Poly-
zoa, 548.)

IlIPPURIC ACID.— This acid occurs in
small quantity in human urine, especially
after a vegetable diet ; more largely^ in that
of the horse and other herbivora, as the ox,
the goat, the sheep, the hare, &c. ; also in
that of some reptiles.

It is readily soluble in boiling water and
alcohol ; less so in cold water and in ether.

It crystallizes in prisms or needles (PI. 11.
fig. 18), belonging to the right rhombic
prismatic system, some of which bear re-
semblance to those of the ammonio-phos-
phate of magnesia, from which it is readily
distinguished by^ its solubility in potash or
hot water. It is sometimes obtained under
the same circumstances as benzoic acid, from
which it differs in its greater solubility in
ether, and in the thickness and solidity of
its prisms, those of benzoic acid being thin
and plate-like. Its crystals are beautifully
analytic; which property is deficient in those
of benzoic acid.

It may best be procured from cow's urine,
by boiling with slaked lime for some time,
filtering and supersaturating with muriatic
acid ; and it may be puritied by repeating
the process and usina" animal charcoal.

HIRNE'OLA, Fi\— A genus of Tremel-
lini (Hymeuomycetous Fungi), consisting of
gelatinous cup-shaped Fungi, horny when
dry, and clothed externally with short vel-
vety bristles. The hymenium is without
papilhe, a character by which it is distin-
guished from Exidia, to which the species
were formerly^ referred. The Jews' Ear
{II. auricida Juda) is still sold by Herba-
lists as a remedy for affections of the throat,
the supposed virtues clearly depending on
the doctrine of signatures. One or two
species are extremely common in tropical
countries; and used as an article of food
in China.

BiBL. Fr. Summa, 340; Berk, Ontl. 289,

HISTOLOGICAL ANALYSIS, See
Introduction, p. xlii.

HISTOLOGY, or HiSTroLOGY, is the
theory of the structure of aniiiial and vege-
table tissues in relation to their develop-
ment ; but the term is often applied to the
microscopic structure of tissues.

HIS'TRIO. — A genus of Ilypotrichous
Infusoria (Kent, Inf.).

IIOLOPH'RYA, Ehr.— A genus of Holo-
trichous Infusoria, of the family Euchelia.

Cltar. Body covered with vibratile
cilia, oblong-ovate, cylindrical or globular,

HOLOSTICIIA.

[ 394 ]

HOPLOPHOEA.

rounded or truncate in front ; no lips nor
teeth ; cilia arranged in longitudinal rows.

Ehrenberg admits six freshwater species ;
to these Dujardin, who places this genus in
the family Paramecia, adds one marine.

H. ovum, E. (PI. 31. fig. 22). Body ovate,
subcylindrical, ends subtruncate ; internal
substance green : length 1-570 to 1-210".

H. hrunnea, D. (PI. 31. fig. 21). Body
brown ; cylindrical, becoming globular when
distended with food, and then changing in
colour; length 1-120".

The eucysting-process has been observed
in two of the species.

BiBL. Ehrenberg, Inf. 314 ; Dujardin,
Inf. 493 ; Cohn, Bieh. und Koll. Zeitschr.
iv. ; Stein, Inf. ; Kent, Inf. 498.

HOLOS'TICHA.— A genus of Hypo-
trichous Infusoria (Kent, Inf.).

IIOLOTHURID'EA (Sea-slugs).— A fa-
mily of Echiuodermata, of the order Pedi-
cellata.

Interesting to the niicroscopist, from the
presence of curious calcareous plates, &c.
existing in the integument.

See ECHINODKRMATA.

HOLO'THYRUS, Gerv.— A genus of
Gamasea (Acariua).

II. coccinella is nearly as large as a lady-
bird (Coccinella), and is found in the Isle of
Erance.

Blbl. Gervais, Walckenaer'' s Apth-es, iii.

IIOMALOCOC'CUS, Kutz.— A genus of
Coufervoid Algpe, consisting of cells united
into flat oblong irregular corpuscles, en-
closed in a spherical gelatinous sheath.

H. Ilassallii ; green, size of a pea or nut ;
in stagnant pools. (Eabeuli. Fl. Alg. 09.)

IlOMffiOCLA'DIA, Ag.— A genus of
Diatomacese.

Char. Frustules those of Nitzschia, ar-
ranged in tufts within gelatinous tubes,
which form a filiform, usually branched
frond. Marine.

H. Martiana, Ktz. {II. am/lica, Ralfs)
(PI. 19. fig. lo : (t, portion of frond ; h, part
of a filament containing two frustules; c,
front view of single frustules, with endo-
clu'ome ; d, side view of empty frustules).
Frond simple or dichotomously divided,
rugose ; entire plant 1 to 2" high.

Il.fiUfonnis. Erond linear, simple, tufts
containing three or four frustules.

Il.sifinioidea. Frond linear, simple ; frus-
tules sigmoid.

Rabenhorst describes 8 European species.

BiBL. Kiitzing, Bacillar. 110, and Sp. Ah/.
97; Ralfs, Ann. ^\ II. 1845, xvi. 109;

Smith, Br. Diat. ii. 80; Eabenhorst, Fl.
Alff. i. 160.

HOM'OPUS, Furst.— A genus of Hypo-
pidte (Acarina). H. elephantis, found on
the dried skin of an elephant, = the hypopial
nymph of Acarus dumesticus, Megnin.
(Fiirstenberg, Kriitzmilhen, 222 ; Miu-rav,
Ec. Ent. 253 (fig.) ; Megnin, Paras, l-il .)

HOOF. — The hoofs of animals consist of
the same structure as horn.

HOOKE'RIA, Smith.— A genus of Hyp-
noid Mosses.

Two species, on moist banks and wet
rocks.

BiBL. Wilson, Bryol. Brit. p. 415.

HOP. — Thehop plant {Humuhis Liipidus)
is remarkable for the glands containing the
resinous secretion imparting the aromatic
odour. These occur on the lower face of
the leaf, upon the calyx, and above all, on
the scales of the fruit and the seed-coat.
They have been examined by Meyen and
others, mostly recently by Personne. They
are little stalked cups (PI. 2S. fig. 14) com-
posed of a single layer of cellidar tissue,
concave above at first ; but as the secretion
increases in quantity, the cuticle becomes
detached in a plate from the upper surface,
except at the rim of the cup, and is pushed
up so as finally to form a convex papilla on
the top, like the nut projecting from an
acorn-cup. The secretion appears to be
formed in the cells, and poured out beneath
the cuticular pellicle, which is marked with
lines corresponding to the side-walls of the
cells. Solution of potash and alcohol clean
awaj" the resinous secretion, and render the
structure clear. When the fresh glands are
placed in water, they swell, and finally burst,
the cuticidar lid usually separating by a cir-
cumscissile dehiscence.

The hop is subject to a peculiar mildew,
a minute fungus, for which see Ekysiphe
{Sphcerotheca).

BiBL. Meyen, Secretions- Organe d. PJlan-
zen, 38, pi. 5. figs. 17-21 ; Personne, Ann,
Sc. N. 4 ser. i. 299, pi. 17.

HOPLITOPIl'RYA, St.— A genus of
Ilolotrichous Infusoria.

Char. Ovate or elongate, mouthless, with
a ventral anterior band or one or more
hooks. Internal parasites. Seven species :
in tlie intestine of Lumbrici, Plunarice, &c.
(Kent, /?(/: 571.)

HOPLC)ri]'ORA, Koch.— A genus of
Oribatoa (Acarina).

Char. Body and general habit those of
G alumna, but no wing-like appendages to

IIORMIDIUM.

[ 305 J

HORN.

the psoudo-thorax ; cephalotliorax articu-
laicd to the abdomen, ibldiug upon the

bodv.

Two species ; on decaying fii--wood and

roots.

BiBL. GeiTais, iralclrnaer's Aplcrcs, lu. ;
Claparede, Zeit. wiss. Zool. xviii. ; Murray,
Ec. Eni. 2i>2; Jn. Mic. Soc. 1880,177.

HOliMID'lUM.— The group of species
of Ulothriv gTO\A-iug upou moist earth.

HOKMIS'CIA, Aresch.— A genus of
Confervoid Algffi, close to Ulothrix ; with
the tilaments jointed, usually simple, but
sometimes emitting ramules ; cells with
thick, often lamellar walls ; propagation by
macro- and micro-gonidia. i'resh and salt
water. (Habenh. Fl. Ah/, iii. 361.)

HORMOS'PORA, Breb.— A genus of Pal-
meUaceae (Confervoid Algse), A,Aith a frond

Fig. 336.

Fig. 337.

Hormospora transversalis.

Fragments of gelatinous filaments, with the cells
grouped in fours.

Magnified 350 diameters.

consisting of simple or branched gelatinous
confervoid cords enclosing rows of oval or
spherical cells ; they are found floating
among Confervas or other aquatic plants,
and appear to the naked eye lilie greenish
filaments. These plants do not appear to
consist of septate fliamentous tubes like the
ConfervEe, but of rows of individual cells
imbedded in a filifurm gelatinous tube
(fig. 336), analogous in its nature to the
gelatinous coat investing the linear rows of
cells of Hyalotheca, &c. The cells multiply
by transverse division, the rows thus becom-
ing elongated; these cells contain green
contents arranged in a granular, lamellar,
or radiating form. Brebisson describes ob-
scurely another mode of increase, in which
the " endochrome becomes concentrated and
organized into vesicles or zoospores. The
corpuscles then become larger; and the fila-
ment becoming as it were dislocated, the
corpuscles group themselves in several rows,
and without regular form " (fig. 337). In

H. transvermlis there is an especial tendency
to a grouping of the cells in fours. Five
species have been described ; 1 and 3 are
known as British.

JI. Dtutahilii^, Breb. Filaments simple ;
cells ovoid or subspherical ; cell-contents
lamellar ; freshwater. Breb. A)ui. Sc. Nat.
3ser. i. ph 1. tig. 1.

IL transversalis, Breb. (figs. 336, 3.37).
Filaments simple ; cells ovoid or fusiform,
transverse ; contents granular ; freshwater.
Breb. I. c. fig. 2.

H. ramosa, Thwaites. Filaments
branched ; cells oval or spherical ; contents
radiated. In a pool to which salt water
had access. Harvey, Phyc. Brit. pi. 213.

BiBL. Brebisson, Ann. Sc. Nat. 3 ser. i.;
Harvev, JJr. Mar. Aly. 235, pi. 27 B, Phyc.
Brit. pi. 213 ; Niigeli, Einzell. Aly. 7, pi. 3.
fig. B ; Rabenhorst, Fl. Aly. iii. 48.

HORN. — The horns of animals are of
three kinds, — those composed of bone, those
consisting of epidermic formations, and
those in which both are present. The former,
properly called antlers, agree in minute
structure with bone, and therefore require
no special notice. The horn of the rhino-
ceros may be taken to represent the structure
of the second kind. It consists of an aggre-
gation of horny fibres, each of which is made
up of a series of concentric laj'ers. These
layers are composed of cells tangentially flat-
tened, and sometimes containing pigment.
The cells may be separated by macerating
the horn in solution of potash. Cracks
filled with air are frequently visible between
the laj'ers. The centres around which the
laminas are arranged probably correspond to
papillas of the cutis. The horn of the
bufl'alo agrees essentially in structure with
that of the rhinoceros.

The third kind of horn is exemplified by
that of the cow. In its centre is a process
of bone, surrounding and extending beyond
which is the proper horn, consisting of con-
centric layers, in the natural state composed
of flattened, irregular, angular, nucleated
cells (PI. 22. fig. 29 o), which assume their
primitive forms under the action of potash
(6) ; some of them contain pigment (d).
Between the laminte, cracks containing air
are also met with (/").

Sections of horn maile at various angles to
the axis, form very beautifid polarizing ob-
jects ; the gorgeous colours seen in those of
rhinoceros's horn cannot be excelled, nor can
drawings represent them faithfuUv (PL .30.
figs. 37, 38). The horn of the bufthlo

HORNBLENDE.

[ 396 ]

HYDATIN^A,

also forms an interesting object of the same
kind.

BiBL. Bonders, Mulder^s Phys. Chem. ;
Owen, Brande's Diet., art. Cornua.

HORNBLENDE. See Rocks.

HOR'NEUA, Lam.— A genus of Cyclo-
stoniatons Polyzoa, 2 species. (Hiucks,
Poh/zoa, 407.)

HORSE-LEECH. See H^mopis.

HUXLEY'A, CI. & Lachm.— Agenus of
Hypotriclious Infusoria, of the family Er-
TJlina. T\\'o species :

//. snlcafa. Jiody greatly compressed ;
cuticle with oblique furrows. Bergen.

II. crassa. Body scarcely compi'cssed,
almost as thick as broad, thickest bt'hind ;
cuticle smooth ; length 1-1250". Bergen.

BiBL. Clap. & Lachmann, Inf. 290.

HUXLP]Y'A,Dyster. — A genus of Chei-
lostomatous Polvzoa. H. frayilis, Tenby.
(Hincks, Pohr.. 2d.)

HYALODIS'CUS, Ehr. = Cyclotella,
Kiitz. in part.

H. Iccvis = CycloteMa Icevis ; Il.-patagonica
= Cyl. pat agon. ; H. suhtilis, Bail., with
extremely tine dots, is used as a test-object.

BiBL. Ehreubcrg, Perl. Per. 1845, 78 &
155 ; Kiitzino-, Sp. Alq. 20.

HYALOM'MA, Koch.— A genus of
Ixodes, (Acarina), wdth the eyes clear, dis-
tinct and conical. Three or four species,
occurring in the Caucasus and Spain.
(Koch, Uehers. ; Murray, Ec. Ent, 196,
figs.)

ITYALOP'TERUS, Koch.— A genus of
AphidfE. DilFering from Aplns chiefly in
the shortness of the tail and nectaries, and
the oval, often linear form of the body. Six
species : found on the plum, the reed, the
moss-rose, the columbine, iiilene injjata,
and Eriophorum, (Buckton, Aphides, Pay
Soc. ii. lOi).)

HYALOSI'RA, Kiitz.— A genus of Dia-

tomacea3.

Char. Frustules compound, rectangular,
tabular ; with alternate vitta;, interrupted
in the middle, and connected with those of
the opposite side by fine lines ; loAvcrmost
frustule attached by a stipes which is affixed
to one angle. Marine.

The fine lines at the end of the vittte
give the latter a forked appearance. The
frustules are often partly separated, so as to
be connected with each other by one angle

only- p ^

Four species, probably forms of Tetracy-

cliis. .

II. rectamjula (PI. 17. fig. 1). Stipes

short, fi'ustules subconcatenate, in front view
subquadrate ; rectangular ; length 1-1360".

BiBL. Kiitzing, Pacillar. 125 ; Sp. Alg.
115 ; Rabenhorst, Fl. Ah;, i. 306.

HYALOSPIIE'NIA.— A genus of Rhi-
zopoda (Bronn, Klass. kc, pi. i. fig. 18).

HYALOTHE'CA, Ehr.— A genus of
Desmidiaceae.

Char. Cells united into an elongated,
cylindrical filament, which is surrounded
by a gelatinous sheath ; cells in front view
slightly constricted, so as to give the margins
a crenate appearance ; or having a grooved
rim surrounding one end, and forming a
bidentate projection ; end -slew orbicular.

The filaments are not twisted, and are
always of the same apparent breadth. Spo-
rangia orbicular, smooth.

H. dissiliens (PI. 14. fig. 1, front view of
filament; 2, end view). Filament fragile,
margins crenate ; breadth of filament 1-1300
to 1-800". The transparent sheath of this
beautiful object is so delicate as to be easily
overlooked. Sporangia (fig. 314) situated
within the connecting tube.

Not uncommon in clear boggy pools.

II. mucosa. Filament scarcely fragile ;
joints not constricted, surrounded at one
end by a miimte furrowed rim, forming in
the front view a bidentate projection ;
breadth of filament 1-1250 to 1-1100".

The fm-rowed rim of each cell is on the
same side as that of the contiguous cell.

BiBL. Ralfs, Brit. Desmid. p. 51.

HYDATl'NA, Ehr.— A genus of Rota-
toria, of the family Ilydatinsea.

Char. Eyes absent ; jaws two, teeth nu-
merous, free ; foot forked.

H. sevta (PI. 43. fig. 37 ; fig. 38, teeth).
Body conical, hyaline ; margin of rotatory
organ ciliated ; foot robust ; aquatic ; length
1-48 to 1-30". .

This animal forms a favourable subject
for the examination of the typical structure
of the Rotatoria, and is that which Ehren-
berff used as the basis of his investigations
upon tlieir organization.

II. brachydacti/Ia. Segments of foot
short ; body suddenly narrowed at the base
of the foot; aquatic; length 1-144".

BiBL. Ehrenberg, Infus. 412 ; Colin,
Sieh. Si' Koll Zeitschr. vii'.

HYDATIN^'A.— A family of Rota-
toria.

Char. Neither carapace nor enveloping
sheath present ; rotatory organ multiple, or
more than bipartite.

18 genera.

HYDNOGLCEA.

[ 397 ]

HYDRA.

Eyes absent,

"No teeth Eiiferoplea.

Teeth present.

Jaws with numerous teeth Hudafina.

„ with a single tooth Pleuroirocha.

Eyes present,
Eye single,

Eye frontal Furcularia.

„ cervieal.

Foot styliforra Monocerca.

„ forked.

Frontal cilia, no hooks nor

styles Notommata.

Frontal cilia, styles present... St/ncha-ta.

„ hooks Smiridium.

Foot absent ; with cirrhi or fins. Fulijurthra.
Eyes two.
Eyes frontal.

Foot forkeil Diglena.

„ styliform.

With cirrhi Triarthra,

Without cirrhi Eiiffidu.^.

Eyes cervical Dislemiiia.

Eyes three.
Eyes not stalked,

Eyes cervical TriopMhalmus.

Two eyes frontal, one cervical . Eosphora.
Two frontal eyes stalked, one cer-
vical not stalked Otoglena.

Eyes more than three in a sinp;le

group Cycloglena.

Eyes more than three in two groups Theorus.

BiBL. Ehrenberg-, Infus. p. 410.

HYDNOCtLCE'A, Berk. & Ourr.— A
genus of Tremelloid Fungi. H. c/elatinosa
occurs in this country occasionally on very
rotten pine wood. (Berk. & Br. Ann. N,
H. 1871, vol. vii. 429.)

HY'BRA, Linn. (Freshwater Polype). — •
A genus of Hydroid Zoophytes, of the family
Hydridte.

Char. Locomotive, single, naked, gelati-
nous, subcylindrical, but very contractile
and variable in form ; the mouth surrounded
by a single row of filiform tentacles. Pro-
pagation by the formation of gemmce, and
ova upon or within the substance of the
body of the animal.

Hydra viridis (PL 41. fig. 21, adhering to
the radicles of duck-weed {Lemna)). Body
leaf-green, cylindrical or insen.-ibly narrowed
towards the base ; tentacles 6 to 10, shorter
than the body, naiTowest at their origin.

Common in ponds and still waters.

H. vidyaris. Body orange-brown, yel-
lowish or red, cylindrical ; tentacles 7 to 12,
as long as or longer than the body, tapering
to the free ends.

In weedy ponds and slowly running
waters ; common.

H. attenuata. Body pale olive-green,
attenuated below ; tentacles pale, consider-
ably longer than the body. In ponds ; rare.

H. fusca (oligaetis). Body brown or
greyish, lower half suddenly attenuated ;
tentacles 6 to 8, several times longer than
the body. Still waters ; rare.

The characteristic forms of the body can
only be judged of when fully extended in
search of prey ; for wlien the animals are
touched, shaken, or in any way disturbed,
the body assumes very variable forms,
becoming rounded, ovoid, &c.

The structure of the body of Hydra has
been much investigated and discussed. By
some it has been regarded as consisting of
three layers — an internal and external coat,
and an intermediate muscular layer. The
true structure, however, has been pointed out
by Ecker. This author regards the animal
as consisting of sarcode or protoplasm, and
neither furnished with an outer nor an inner
coat. The transparent, gelatinous, sarcodic
substance forms the entire mass of the body
and tentacles ; on the surface it is frequently
irregularly rounded or nodular, or exhibits
spiral or other raised lines (PI. 41. fig 23 6) ;
and it contains numerous vacuoles within.
If a Hydra be crushed between glasses,
portions of the sarcode will be separated,
and assume a globular form, closely resem-
bling that of cells ; the vacuoles will also
become greatly distended, just as occurs in
the substance of the Infusoria ; and these
separated portions will often continue con-
tracting like an Amoeha. Two of them are
represented in PI. 41. fig. 29 ; in a, a rather
small vacuole is present, whilst in h this is
very large. Now in the latter instance the
globule, as regards structure, forms a true
cell, consisting of a closed sac, with liquid
contents-. Physiologically speaking, how-
ever, it does not correspond to a cell, the
entire substance representing cell-contents
aroimd which a cell-wall has never been
formed. A number of these vacuoles exist
naturally, diffused throughout the substance
of the body. The protoplasts of the inner
surfiice are ciliated, and solid particles are
ingfestedbv them as in Amoeba. The inter-
mediate stratum, whicli is not organically
distinct, contains imbedded in it a number
of very minute green or otherwise coloured
granules ; these are of a rounded form, and
present a double outline, as if composed of
cells. In the uninjured Hydra they exist
in the intervacuolar substance, thus giving
the tissue an elegantly reticular appearance.
They appear to consist of chlorophyll ; they
are insoluble in potash ; they become
coloured purplish red-brown by iodine and
sulphuric acid, after ti'eatment with potash ;
and the green-granules of Hydra vulyaris
are rendered bluish green by sulpliuric
acid, in the same manner as the chlorophyll

HYDRA.

[ 398 ]■

HYDEA.

of leaves. The colour of Hydra has been
ditferently accounted for. Laurent states
tliat he succeeded in colouring them blue,
■white, and red, by feeding them with in-
digo, chalk, and carmine, — whilst Hancock
has shown that the colouring is much
affected by exposure to light — those not
exposed to light, from living under stones,
&c., having the natural colour, whilst those
exposed to the light became bleached. It
is generally admitted, however, that the
colour depends upon or is modified by the
nature of the food ; but exact experiments
are wanting to decide the question. Towards
the inner surface of the body, the granules
are brownish or blackish.

Imbedded in the superficial portions of the
substance of the Hydra are certain curious
bodies, termed the stinging organs or nema-
tocysts (PI. 41. fig. 23 rt). These are best
seen upon the tentacles ; they consist of
an oval, truncate, firm capsule (PI. 41.
fig. 22 h) of comparatively considerable
thickness, as indicated by its marked double
outline. Within the capsule is contained
a very long and slender filament, at the
base of which are four minute spines. In
the undisturbed state of the Hydra, the
filament with the spines is coiled up in the
capsule (fig. '22 a); but when the animal is
touched, pressed, or heated, the filament
with the spines flies out with extraordinary
rapidity, so that we have not been able to
determine exactly how the spines are ar-
ranged within the capsule. Most probably
the spines, while within the capsule, are
directed forwards and in close contact, and
then, in assuming their recurved position,
they are the means of projecting the filament
forwards. A capsule, containing an unex-
panded filament and spines enclosed within
a detached globule of sarcode, is represented
in fig. 22 (/. When these capsules are heated
with a solution of nitrate of silver, a portion
of the silver is reduced to the metallic state.
This action is a property of formic acid ;
hence,when it isconsidered that these organs
closely resemble in structure those of the
Acalephre,which possess an urticatiug power
like stinging-nettles,- arising from the pre-
sence of formic acid, and that in Hydra
these filaments are driven into and wound
the prey, it may appear probable that tlu'V
secrete and contain formic acid. IJut, as
many other su1)stances reduce salts of silver,
and as the sarcode, from which it is perhaps
impossible to separate these bodies, may
produce this eflect, the point must be con-

sidered doubtful and requiring further in-
vestigation. In addition to these stinging
organs, we have found other very minute
capsules (fig. 22 c), containing a filament,
curved even when emitted, the nature of
which is obscure.

A third kind of organ is said to have been
met with also in the sm-face of the body,
consisting of ovate capsules or bodies, from
which a stout and short filament projects;
these appear to resemble the organs of ad-
hesion of the Acalephpe.

The body and tentacles of Hydra are hol-
low. The prey, which consists of Entomos-
traca, small Annulata &c., when caught by
one or more of the tentacles extended for
the purpose, is slowly brought to the mouth,
and forced into the cavity of the body, in
which it is digested, certain portions he'mg
taken up by the amoeboid bodies ; the un-
digested portions are evacuated through the
mouth. The posterior part of the body is
more or less dilated into a flattened disk,
which, by its suctorial power, enables the
animal to attach itself to various bodies ;
Hancock has seen excrementitious matter
passing through the body at this part. The
cavities of the tentacles sometimes exhibit
a kind of circulation ; and those of both the
tentacles and the body are lined with cilia.

The extraordinary power which Hydra
possesses of reproducing lost parts is truly
wonderful. Thus, if the body be cut into
two or more, even into forty parts, each
portion continues to live, and develops a
perfect new animal. If the section be made
lengthwise, so as to divide the body all but
the end, the two portions become resoldered
and form a perfect being ; if the pieces be
kept asunder, each becomes a Hydra, the
two possessing but one posterior end ; if the
section be made from the tail towards the
head, the two bodies will be perfected and
remain attached to the one head. If a
tentacle be cut off, a new animal is formed
from it. When one end of the body of a
Hydra is introduced into the body of
another, the two unite and form one. The
head cut off one may be engrafted upon
the body of another which wants one. And
when tiie body is turned inside out, the
outer surface, which has thus become the
inner, will perform the ordinary digestive
functions, and the auiiual will continue to live,

Tlie ordinary mode of reproduction of
Hydra is by gemmation : a minute swelling
forms upon some part of the surface of the
body ; this enlarges, and gi-aduaUy assumes

riVDrvA.

[ 399 ]

HYDRACHNA.

the form of the parent, while remaining
attached to it. Sometimes several of these
are formed upon a single individual at the
same time, and so, remaining adherent,
tliev irive the animal a branched appearance
(Pf. 41. fig. 21).

At certain seasons of the year, as at the
end of summer or in the autumn, reproduc-
tion takes place by the formation of sperma-
tozoa and ova. The spermatozoa are lormed
■n-itliiu spermatic capsules. These arise as
minute conical tubercles a little beneath the
base of the tentacles, one on each side
(PI. 41. fig. 24 a) ; and the spermatozoa are
liberated from them by bursting. The sper-
matozoa resemble those of the Mammalia,
except that the tails are undulate. The ova
are furnished with a thick coat, and are
formed in the substance of the loAver part
of the body (fig. 24 6). They subsequently
sepai'ate from the body, and appear to be
capable of spontaneous motion; but whether
from the presence of cilia or not, is unde-
cided. The ovisac then becomes ruptured,
and the new animal escapes (fig. 25).

Hydne are very common. The best me-
thod of procuring them is to collect a number
of water-plants from any clear pool or slow
stream, and bring them home in an india-
rubber bag (sponge-bag). On placing the
plants subsequently in a glass jar (con-
fectioner's jar) containing water, they will
be found at the end of some hours with the
tentacles fully extended in search of prey,
when they are easily recognized. They
usually adhere to the sides of the glass, oV
to the stems or undersides of the leaves of
the plants ; but sometimes they are seen
suspended from the surface of the water by
the sucker, which is protruded just above
it so as to become partly dry. A number
of small Entomostraca should be added to
the water, as the Hydra are very voracious.

Some of the species of Hydra are occa-
sionally covered with minute parasitic Infu-
soria, viz, Kero7ia polyporum (PI. 50. fig. 13),
which is found upon H. vulgaris and fusca,
and Trichodina ^fedieiiliis (PI. 31. fig. 16),
which occurs upon //. vidyaris and vin'dis.
It is an interesting sight to see these running
up and down the tentacles and surface of the
body of the polypes, when we recollect that
their surface is covered with the stinging
organs. These lice are not, however, found
in any numbers upon perfectly healthy
poly})es, impurity of the water and an un-
healthy state being generally denoted by
their presence.

Parker recommends osmic acid in the
examination of the minute sfructure of
Hydra ; and hardening in bichromate of
ammonia for sections.

BiBL. Leeuwenhoock, Phil. Tr. 1703,
xxiii. ; Trembley, Polyp, d'eau douce. ; Lau-
rent, Rech. s. VHydre ; Corda, Ann. Sc.
Nat. 2 ser. viii. ; ScliaefFer, D. Armpoh/p. ;
Erdl, 3Iiiller's Archiv, 1841 ; Ecker, Sieh.
and Kiill. Zeitsch. i. ; Johnston, Br. Zooph. ;
Thomson, Todd^s Cycl. An. and Phys. iv.
17 ; Hancock, Ami. N. H. 1850, v. 281 ;
Allman, Micr. Journ. 1854 ; Hincks, Br.
Zooph. 309 ; Kleinenberg, Hi/dra., 1872 ;
Allman, Qu. M. Jn. 1874, xiv. 1; T. Parker,
Pr. Roy. Soc. 1880, 61.

HYDRACH'NA, Mlill. — A genus of
Acarina, family Ilydrachnea.

Char. Palpi tolerably long, thii-d joint
longest, the fourth and fifth terminated each
by a claw ; mandibles ensiform ; rostrum
long, scarcely shorter than the palpi ; body
rounded ; eyes distant ; vulva concealed by
a plate or shield.

When young, these little water-spiders
have three legs only, and in this state have
formed another genus, Achlysia. Several
species :

H. cruenta, Miill. = H. glohula, Herm.
(PI. 6. fig. 29). Body subovate ; two pairs
of eyes at a moderate distance apart, reni-
form, dark red ; slriu covered \vith minute
puucta.

The rostrum is broad and cuiTed at the
base (fig. 29 c, the lower part directed to the
left), cleft above, so as to form a kind of
channelled sheath, containing the anterior
narrower portions of the two mandibles (b).
Tlie palpi (c, upper organ) are inserted upon
the sides of the base of the rostrum and
curved downwards ; the first joint is very
broad, the second much curved, the third
long, and flattened on one side and rounded
on the other ; the foiu'th joint is short, and
terminated by a short and thick claw ; the
fifth also forms a claw, but the two claws do
not form a chela, their curves being parallel.
Of the legs (fiff. 29 a), the three posterior
pairs are ciliated for swimming, and the
posterior are much longer than the anterior ;
the coxfe are flattened and form two groups
on each side ; between the two posterior
coxne is the orifice of the reproductive
organs ; the tarsi all have two claws, and
are obliquely truncated and concave at the
end (fig. 29 e).

Tlie eggs are reddish-brown and deposited
upon the stems of water-plants ; the nymphse

HYDRACHXEA.

[ 400 ]

HYDrtOCYTIOr.

are found attached to aquatic insects (fig.
29 f), as Nepa,Dyti><cus, &c.

H. geographica. Body spherical, black,
with spots and yellow points ; palpi red,
acute ; legs shorter than the body, black,
but red at the ends.

H. concharum. Inhabits the pallial cavity
of the Naiades.

BiBL. Duges, An. Sc. Nat. 2 ser.i. ; Ger-
vais, Tf^alckenaers Arachn. iii. ; Koch,
Deutschl. Cnistac. ; Muri'ay, Ec. Ent. I-jZ.

H YDRACH 'NE A (Water-spiders).— A
family of Acariua.

Paipi with the last joint unguiculate or
spinous ; two or four distinct ocelli ; coxfe
broad, legs generally ciliated, natatory, the
posterior longest, tarsi with two claws.

The characters of the genera must be
sought under the individual heads. See

AREENUEXJS,ATAX,DlPLODONTUS,EYLAiS,

Hydeachna, and Limnochakes.

HYDRACTIN'IA, V. Bened.— A genus
of Hydroid Polypi, of the family Ilydrac-
tiuiidse.

Char. Polypidom incrnsting ; polypes
claviform, tentacles in a single whorl at the
base of a conical proboscis.

H. echinata. Polypidom rough with ser-
rated spines, whitish fleecy. On univalve
shells tenanted by the hermit crab.

BiTiL. Hincks, Brit. Zooph. p. 19.

HYDEALLMAN'IA, liincks.— A genus
of Hydroid Zoophytes, fam. Sertulariidas.

H. faJcata= Elvmularia fate. Johnst.

BiBL. Ilincks, Brit. Zonph. p. 273.

HYDRAN'THEA, Ilincks— A genus of
Hydroid Polypi, fimi. AtractylidiB.

JI. margaritacea, white ; on Flustra
foliacea.

BiBL. Hincks, Ann. N. 11. 18G.3, xi. 45 ;
and Br. Zooph. 99.

HYDKIA'NUM, Rab.— A genus of Pal-
mellaceous Algae.

Char. Cells resembling those of Chara-
cium, but open at the ends ; endochrome
contracted, ultimately becoming resolved
into 2-4-8 zoogouidia. H. ovale (PI. 52.
fig. 5).

12 species : freshwater ; adherent to other
Algae.

BiBL. Babenhorst, Fl. Alq. iii. p. 87.

HY'PRIAS, Elir.— A genus of Rotatoiia,
of the fauiily Philodiufea.

Char. Eyes absent ; neither proboscis
present, nor horn-like processes on the foot ;
rotatory organs two, placed at the ends of
two antvrior processes of the body.

JI. cornigera (I'l. 4o. fig. o9_). Body ovate,

hyaline ; foot narrowed into the form of a
slia'litly forked tail ; freshwater ; length
1-190".

Probably a young and imperfectly exa-
mined Phitodina. Found in Egypt.

BiBL. Ehrenberg, Tnfiis. p. 483.

HY'DRIDiE.— A family of Zoophytes,
order Hydroida.

It contains the single genus Hydra.

IIYDROCHARIDA'CE.E.— A familyof
Mouocotyledonous Flowering Plants gi-ow-
ing in water, interesting to the microscopist,
as affording very favourable opportunities of
viewing the circulation or rotation of the
cell-contents. The leaves of VaUisneria
spiralis, an Italian plant, which is readily
grown in jars of water indoors, are vei-y fre-
quently used for this purpose ; the leaves
and sepals of Anacharis Alsinasini7n, si's oith
American plant, now naturalized in streams
in many parts of Britain, also show the cir-
culation well. The extremities of the roots
of Ui/drocharis morsus-rancc, a plant com-
mon, floating on tlie surface, in broad per-
manent ditches, are likewise adapted for the
purpose. The circulation consists of the
tioAving movement of a layer of colourless
protoplasm over the inner surface of the
walls of the cells. Where, as in the leaves
of VaUisneria and Anacharis, the cells con-
tain green globules of chlorophyll, these
mostly adhere to the circulating mass, and
are carried rouiid with it. The phenomenon
may be observed in iminjured young leaves
simply immersed in water by focusing care-
fully ; but in VaUisneria it is seen more
clearly in slices taken carefully parallel to
the surface of the leaf. The circidation
lasts a long time in these separate frag-
ments if they are kept wet. Sometimes it
is arrested by the preparation ; in such cases
the application of a gentle heat often causes
it to recommence. It may be observed with
a power of 200 diameters ; but a higher is
requisite for minute investigation. (See
Rotation.)

HYDROCTIOREUTES, Koch, = Ilgd-
rachna, pt.

IIYDKOCO'LEUM, Klitz.— A genus of
Oscillatoriaceae (Confervoid Algaj), corre-
sponding to aquatic species of Chthono-
hlanttis. II. helreticnm (P\. 52. fig. 0).

11 European species.

BiBL. Kiitzing, Plu/c. Gen. 196 5 Raben-
horst, Fl. Ah/, ii. p. 149.

IIYI)R0CY'T1UM, Al. Braun.— A genus
of unicellular Algne, separated from that
author's Charucium on account of the whole

IIYDRODICTYON.

[ 401 ]

IIYDRODICTYON.

Fig. 338.

contents becoming at once broken up into
active gouidia, not by successive subdivi-
sions (PI. o. tig. 1). Green. Found upon
stones or tilanientous Confervas iu fresh
water, and consisting of elliptical sacs or
cells, acuminate above and below, about
1-500" long and l-li^OO" thick. 2 species.

BiBL. Al. Braun, Alg, UniceU., Leips.
1855, 24.

HY'DRODIC'TY'ON, Roth.— A genus of
Siphouacese (Coufervoid Algae), containing
one species, //. utricukifum, found iu fresh-
water pools in the midland and southern
counties of England. The froud or coeno-
bium consists of a gi'eeu open network of
filaments attaining a length of 4 to ()'' when
full-grown (tig. 338), composed of a vast
number of cylindrical tubes
(cells) with rounded ends,
adherent together at their
extremities, the points of
junction corresponding to the
knots or intersections of the
network. The indi^•idual
cells attain a length of 4'" or
more. The organization of
this plant and its develop-
ment are exceedingly curious;
and it has lately been the
subject of very careful inves-
tigation by Al. Braun and
others. The cells formuig
the links of the net have a
remarkably thick cellulose
coat when full-grown, which
exhibits several layers, espe-
cially when treated with sid-
phuric acid (PI. 47. tig. 24/).
Weaksulphm-ic acid does not
affect the outer cuticular A complete frond

1 T •■! •j_ 11 ii ornet, about rta

layer, while it swells the of the largest
inner layers, and throAvstheni size,
into waves, especially the in-
nermost ; the subsequent addition of iodine
colours the inner layers blue, but not the
cuticle. Strong sulphuric acid acts diffe-
rently : it detaches the cuticle at many
points, while the inner layers contract, so
that the cuticle appears blo-v\Ti up in vesicles ;
the inner layers gradually soften and dis-
solve. These last changes are similar to
what takes place at the dissolution of the
cell when the contents escape ; and Cohn
states that the membranes give the bluish
reaction with iodine alone when thus par-
tially decomposed by natural causes.

Immediately lining the wall is a mucila-
ginous layer (PL 47. tig. 24jjJ, which Braun

Hydrodictyon
utriculatum.

has shown to consist of several lamellaj : — ■
1. An extremely thin, finely punctate layer,
coagulated and detached from the cell-wall
by the action of aeids ; this is the primor-
dial utricle of the cell. 2. The outer muci-
lat/inous layer, thicker than the primordial
utricle, but thinner than the next or third
layer. When separated from the first layer,
the outer surface appears rough and wavy ;
and it is connected with the third layer by
mucilaginous cords ; it contains indistinctly
defined colourless granules. 3. The inner
mucilaginous layer, the thickest of the three,
is rough on the outside and waved on the
inside from the projection of granules im-
bedded in it ; this is the only green layer,
appearing of a homogeneous green colour
(like the spiral bands of Spiroyyra) when
the cells are in their prime, besides which
it contains innumerable green granules,
sometimes in rows, more frequently uni-
formly scattered. This layer likewise con-
tains starch-corpuscles, such as occur com-
monly in the green substance of the Oonfer-
voids, causing the cell-contents to exhibit a
vast number of brilliant points. In imperfect
cells the green layer sometimes appears in
patches, not completely investing the sur-
face of the outer mucilaginous layer ; this
is also common in young cells. The fluid
in the cavity of the cell is clear and watery.
The reproduction of the fronds of Hydro-
dictyon is efi'ected by the conversion of the
contents of the individual cells into com-
plete new sets like the parent, which lets
them free by dissolution. The following is
a brief history of this remarkable process.
The first stage is the solution of the starch-

grams ;

the

layer becomes more

opaque ; lighter spots appear on the inner
part of the mucilaginous layer, excavated
in its substance and surrounded by the
chlorophyll-globules, which separate*^ from
each other, forming dark boundary lines
round the light spots. The bright- green
then gives place to a browner tinge. The
light spots already observed (the centres of
the nascent gonidia), exerting an attraction
as it were on the chlorophyll-globules, be-
come severally enveloped in a layer of them,
and then separate from each other, so as to
appear like dark spots with an intervening
reticulation of bright lines. The dark spots
(gonidia) are now polygonal, mostly six-
sided, about the 1-2500" iu diameter. The
parent-cell membrane next begins to soften
and swell up ; the gonidia, thus acquiring
more space, become rounded, and soon pre-

2ji

HYDRODICTYON.

[ 402 ]

HYDROIDA.

sent a slight tremulous oscillatoiy niove-
mt'ut. The cuticle of the parent cell then
cracks, allowing the inner softened layers
to swell out; the gonidia commence an
active trembling and jerking motion, not,
however, moving far from one spot ; after a
time they again come to rest, and become
united at certain points of their circum-
ference ; the green granules become fused
into a homogeneous mass, and the rudi-
ment of the first starch-granule soon ap-
pears, while the gonidia grow out into a
tubular form, acquire a cellulose membrane,
and collectively form a new net, which be-
comes free by the total solution of the pa-
rent cell. Tliese gonidia appear to possess
four short cilia ; their motion lasts about
half an hour ; from 7000 to_ 20,000 occur in
one cell : and thej' are distinguished by
Braun as macro(/on{clia. Other gonidia of
smaller size and longer shape, which he
calls microyrmidia, are furnished with four
long cilia and a red parietal spot. These
have a different history. From 30,000 to
100,000 appear in the parent cell, their de-
velopment presenting the same characters
as that of the macrof/onidia up to the time
when the motion begins. Then the micro-
(jonidia, unlike the net-forming VKtcror/oni-
dia, leave their parietal positions with a
whirling motion, and move through the
entire cavity of the parent cell, until at
length the membrane of the latter bulges
out in one or more places and bursts, and
the microgonidia leave the cavity in a
swarm. According to Colin, they are at
first enclosed in a thin mucilaginous pellicle
protruded before them, like the swarming
spores of Pediastrum. However, they
escape, become free, and swim about for a
long time, and are sujiposed to conjugate.
At length thej' come to rest, acquire an
outer coat, sink to the bottom, and remain
there heaped in green masses, like cells of
Protococcus, for a long period, forming
resting-spores.

The rapidity of the growth of the JTi/dro-
didyon-nei by the above process is wonder-
ful ; the component cells of the net increase,
under favourable circumstances, to 600 times
tlieir original length in a few weeks. In
cultivated specimens, the whole history,
from the origin of a net to the production
of a new one, passes over in tliree or four
weel\s. The original size of the cells is
about 1-2500"; in the fully developed con-
dition they are about 1 to 4" long.

PiBL. Vauchcr, Confcrves, ^2, pi. 9 ;

Areschoug, Linrupa, xvi. 127, pi. 5 (1842) ;
Ilassall, AhfcB, 225, pi. 58 ; Braun, Ver/ihiy.
(Hay Soc. '185.3) ; A/y. UniceU. Sp. ' Nov.
1855, 55 ; Cohn, Nova Acta, xxiii. 207, pi.
19; Pringsheim, ^«-/. i?er. 1800; Qu. M.
Jn. 1802, 54, 104.

HYDROGAS'TEUM, Desv. = Botby-
DirrM.

HYDROI'DA.— The order of Hydroid
Polypes (Zoophytes).

The members of this Order usually con-
sist of aggregate hydriform individuals
contained in cells or cups, springing from a
filiform branched polypidom ; propagation
gemmiparous and oviparous. Many new
names have been used for the component
structures, which may well be mentioned
here ; but we prefer the old ones. One of
the forms of non-sexual reproduction is the
zooid. Zooids ditler from organs in that
the zooid is an individual organism, which
may or may not be capable of individual
existence. A community of zooids in imion
with one another constitutes the hydrosnme.
Zooids are of two kinds : in one, destined
for the nutrition of the community, the as-
semblage is called the trophosome;t\\e oihex
gives origin to the generative elements —
ova and spermatozoa ; and the entire asso-
ciation of these generative zooids is the
yonosome. The trophosome is composed of
the hydranih and the liydruphyton. The
hydranth or polypite contains the digestive
sac ; the hydrophyton or ccenosarc is the
common basis -by which the general com-
munity is kept together. The hydrorhha
is the adherent base. The ultimate zooid,
which generates either the ova or the
spermatozoa, is the yonojjhore. The spo?-o-
sac is the gonophore without the umbrella.
The yonozoid is the sexual zooid, whether
fixed or detached and fitted for locomotive
life ; this is also known as a medusiform
gonophore, or planoblast. The ytmaxyium,
or (/onothcca, is an external receptacle in
which the gonophore is formed. (Pascoe.)
See Zoophytes.

Ilincks divides the Order into 3 sub-
orders : —

1. Athccata (Tubularina, Johnst.), in
which true thecse are absent. Fam. :

Clavidas.

Jlydractiuiidfe.

I'odocorynidje.

Ijavida^..

Coi'vui'l-e.

Stauridiida).

Clavatellida).

jMyriothelidas.

Eudeiidiiidie.

Atiactylidie.

TubulariidiT}.

Penuariidaj.

IlYDKOMETrvID.E. [ 403 ]

HYDRURUS.

2. Thecaphom (Sertularina, Johnst.), in
■wliich the Ilydroida are furuished with
thocae. Faiu. :

Campamiliiviidre.

Campaniiliiiid;i3.

Leptoscyphidse.

liafoeidiB.

Trichvdridte.

Coppiniid.*B.
Haleciida\
Sertulariidic.
Phimulariida3.

3. Gi/mnochroa (Ilydrina, Johnst.). Poly-
pidom* absent; locomotive. Fain. 1. Hy-
diidfB.

The polypidoms of the Ilydroid Polypi
form interest iiiij microscopic objects. They
are very common among sea-weeds, on
shells, rocks, &c., the forms being often
elegantly branched and feathery (PI. 41.
figs. 4, il, lo, 1()) ; and the species can be
identified from the polypidoms. They may
be monnted, after being well-washed in
distilled or rain-water, in balsam or glj^-
cerine. The animals are very irritable and
contractile, and can only be observed after
the removal of the bodies to which they are
attached to an aquarium or jar containing
sea-water.

BiBL. Joliuston, Br. Zoopk. 5 ; Gosse,
Mar. Zool. 1, 18 ; Allmau, Ann. N. II. 18G3,
xi. 1 ; Hincks, Br. Zooph. i ; and Ann. N. H.
1877, xix. 148, 1878, i. 239 ; 1880, vi. 277
(Barenfs Sea) ; Mereschowski, ibid. 1878,
ii. 251 ; Korotneft", ibid. 1878, ii. 351 ;
Thompson, ih. 1870, iii. 97 ; Pascoe, Zool.
Class. 1880.

HYDROMET'RID.F;.— A family of He-
mipterous (Heteropterous) Insects, the spe-
cies of which are found skimming the sur-
face of pools or rivers. The under parts of
the body and legs are covered with fine
hau-s, which prevent them from becoming
wetted. The eggs of Ilydrometra are ellip-
tical and elegantly sculptured.

BiBL. Westwood, Infroditction, ii. 407.

HYDROMOKI'NA, Ehr.— A family of
Infusoria.

The two genera of which it consists, Po-
lytoma and Spondyhimorum, appear to be
Monads, or species of Algaj, undergoing
division. See these genera.

BiBL. Ehrenb. Ber. d. Berl. Akad. 1848.

H Y1)R( )PH 'ILUS, Geoff'. See IlYDEOf s.

HYDR()PH'ORA, Tode.— A genus of
Mucorini (Pliycomycetous Fungi). 3Ioulds
growing on the dung of animals, distin-
guished by the indurated persistent peridiole
and the conglobated spores. Two species
are described as British.

H. stereorea, Tode. Fleecy ; filaments
simple, very long, fugacious, white; peri-
dioles spherical, yellow, subsequently black.
Common on dung after much rain,

H. mnrina, Fr. Filaments scattered,
short, simple, persistent, white ; peridiolus
yellow, subsequently opaque. On rats' dung.
i^Mucor fulviis, Sowerbv, pi.' 400. fig. 4.)

BiBL.' Berkeley, Hook. Br. Fl. ii. pt. 2.
331 ; Fries, Syst Glycol, iii. 314, Smn. Fey.
87.

IIYDROSE'RA, Wall.— A genus of Dia-
tomacete.

C7iar. Frustules quadrate, areolar, united
into a filament, with internal septa ; hoop
smooth, compressed or triangular in front
view, areolar, the constricted angles with a
small appendage on one side. Marine.

//. compressa. Valves oblong. East Ind'es.

//. triquef.ra (PL 51. fig. 40). Valves
triangular. East Indies.

H. tricoronata. New Zealand.

BiBL. Wallich, Qii. M. J. 1858, vi. 251 ;
Stolterforth, Jn. Mic. Soc. 1881, 424.

HYDRO'tJS, Linn.— A genus of Coleo-
ptei'ous Insects, of the family Hydrophilidfe.

H. picens is one of the largest aquatic
British beetles. We have selected the head
to illustrate the structure and arrangement
of the trophi, &c. in the Coleoptera (see
Insects). The perfect insect is about I5"
in length. The fuU-groAvn larva is about 3"
long; it has no lateral branchiae, but two
filiform branchial appendages at the end of
the body.

BiBL. Westwood, Introduc. ; Dumeril,
Consid. gen. s. I. Insectes ; Stephens, Br.
Beetles.

HYDRU'RUS, Ag.— A genus of Pal-
mellaceaj (Confervoid Algfe), which seems
to form a link between these and the Ul-
VACE.'E. The frond consists of a branched,
feathery, very gelatinous expansion, the
branches set with minute processes or ra^
melli (PI. 7. fig. Sa) ; in the gelatinous
substance are imbedded minute cells AA-ith
homogeneous green contents, most closely
set in the ramelli, more scattered in the
older part of the frond (PI. 7. fig. 8b). II.
Di<cliizelii, Ag., grows to a length of from
1 to 6", and from 2 to 4'" in diameter,
attached to stones in •mountain-brooks and
rivers ; the recent frond is of brownish
olive in mass, green when dried. When
fresh it has a very offensive smell. Repro-
duction by active gonidia.

BiBL. iTarvev, Br. Ah/. (1 ed.) 180;
Hassall, ^%. 302, pi. 77. "fig. 3; Kiitziug,

2d2

HYGHOCEOCIS.

[ 404 ]

H13IEN0MYCETES.

Tab. PJujc. pi. 34. fig. 3 ; Rabenliorst, Fl.
Ah/, iii. 49.

HYGKOCEO'CIS, Ag.— A supposed
genus of filamentous Coufervse; apparently
consisting of the flocculent mycelium of
Fungi. II. arscnica occurs in sulutiuus of
ar.senious acid.

BiBL. Kiitzing, *S);. Alg. 148; Eaben-
horst, Fl. Al(j. ii. 8 (fig.) ; Marchand, Compt.
rend. 1878.

IIYME'NIUM. — The term applied to
the layer of cellular tissue upon which are
seated the hasidia of the higher Fungi.
The name is also applied to the fructifving
stratum in such Ascophorous fungi as Ilel-
vella, Morchclla, Pcziza, &c.

HYMENO'MONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Free, -svith a crenate, flexible cara-
pace; flagella two; no eye-spot; lateral
yellow-brown pigment bands present.

H. roseola; length 1-850''; freshwater.
(Kent, Inf. 407.)

HYMENOMYCE'TES.— A tribe of Ba-
sidiomycetous Fungi, characterized by the
peculiar mode of arrangement of the spores,
which are borne in groups of four on the
exposed surface of a more or less membra-
nous or sometimes gelatinous layer called
the hymenium. The fruit, called the re-
ceptacle, varies extremely in form. In
most of the Tremellini it is an irregular
jelty-like or waxy expansion, borne how-
ever on a roundish support in Tremella; in
the Clavati it forms a club-shaped, mostly
branched, fleshy or leathery stalk-like body
(called the hymenophore), which is clothed
at its ends by the sporiferous membrane or
hymenium, forming a smooth layer. In
the Auricidati and Ilyduei the receptacle
is either an expanded, irregular, crust-like,
membranous or leathery mass, or has the
form of a club, a funnel, or of a hat or cap,
the sporiferous membrane clothing either
the upper or under surface as a warty,
spiny, or comb-like stratum.

In Polyporei and Agaricini the receptacle
is a discoid (olten laminated), bell-shaped
or dish-formed, fleshy body, more or less
coloured and tuberculated on the upper side,
frequently borne on a columnar stalk in-
s 'I'ted on the under side, while the sporife-
rous layer, or hymenial structure, presents
itself as a conspicuous layer on the under
side, consisting of a number of paper-lil<e
la in el he, or vertical tubes, prickles, or pits,
closely packed, on the lateral surfaces of

which are borne the

spores ; in many^

cases, however, the hymenium is perfectly
even in the column. The younger stages
of development of some Plymenomycetes
do not exhibit aU these characters, since
the receptacle is at first enclosed in a sac-
like body arising from the myceliima, so
that the external appearance is similar to
that of one of the Gasteromycetes (as in
very young mushrooms) ; this sac finally
bursts, to allow of the expansion of the
receptacle.

The cellular structure of this family is
simple, in spite of the varied outward
forms ; the whole mass, from the filamentous
myceluDn up to the sudoriferous membrane
or hymenium, is made up of . interwoven
branched cellular filaments or hyphae, of
great tenuity. In the Tremellini these fila-
ments are imbedded or dissolved into an
amorphous waxy or gelatinous substance ;
in other cases they form a dry corky struc-
ture ; but the consistence is generally fleshy.
In a few cases among the Agaricini and
Polyporei, vesicrdar or elongated branched
hyphee of considerable size are met Avith,
containing a milliy juice (in the gills of
Afi. deliciosus, Sec.). The spores are short
ternunal branches of roundish or elongated
cells, called basidia, clothing the free surface
of the hymenial structure (see Basidio-
SPORES). They may be seen in thin cross
sections cutting the laminae of the Agarics
or the tubes of the Polyporei at right
angles, requiring a high power for their
observation. Four spores are formed on
each basidium, from which they fall otf
when mature. The Agarics exhibit on the
hymenium, among the basidia, pecidiar pro-
jecting vesicles filled with opaque fluid {pol-
linaria, Corda ; cystidia, Leveille ; utricles,
Berkeley), which some have called anthers,
but which appear to be parciphi/ses — that
is, undeveloped or abortive (bare) basidia.
The spores are mostly exceedingly minute,
of various forms and colours, and consisting
of simple cellules. Tulasue has recently
shown that the TremeUini produce sperma-
tia, as well as basidiospores ; in Tremella,
and other genera, thej' arise from distinct
branches of the hymenial filaments ; in
Dacrymyces they are produced in germina-
tion from some of the detached basidio-
spores lying upon the mycelium (see TuE-
MELLixi).

The structure of these Fungi must be
investigated in all stages of development,
since vei"y great changes of size and
form take place at diflereut epochs, simply

IIYMENOPIIYLLE^, [ 405 ] IIYMENOPIIYLLE^.

from expansion or solution of the cellular
textures.

Si/nopsis of the Families.

Agaricim. Receptacle like a round or
flat cap, ofteuborne on a stalk. Hyme-
nium forming vertical plates or folds on the
under surface.

PoLYPOEEi. Receptacle like a round or
flat cap, disk, cup, or funnel, sometimes
stalked, with a porous (formed of tubes) or
reticulated hymenium on the under side.

Hydxei. Receptacle like a round or
flat cap, cup, or funnel, sometimes stalked,
with the hymenium on the under side ex-
hibitinp^ awl-shaped processes or tubercles.
AuRicuLARiNi. Receptacle tubular,
cup- or funnel-shaped, -with the smooth or
papillose hymenium on the under surface.

Clavati. Receptacles club - shaped,
simple or branched like a shrub, with the
hymenium covering the tips and sides of
them.

TREiiELLiNi. Receptacle vague, or cup-
shaped, often gelatinous at first, hardening
by drying up. Hymenium confounded
with the structure of the receptacle, on the
upper, imder, or both surfaces ; basidia
terminating the branches of hymenial fila-
ments, accompanied sometimes by branches
bearing sperm atia. The detached spores
often lie imbedded in the gelatinous surface
of the hymenium, and sometimes produce
spermatia there. The above characters refer
to the more typical species, as resupinate
forms or an expanded hymenophore occur
in each of the divisions.

BiBL. Berkeley, Lindley's Veg. Kingdom-^
Hooker'' s Br. Flora,yo\. ii. pt. 2; Ann. N. H.
i. 81, and ix. 1; Leveille, ^7(h. Sc. N. 2 ser.
viii. 321 ; Fries, Sum. Veg. 267 ; Tulasne,
Ann. Sc. N. 3 ser. xix. 193.

HYI^IENOPHYL'LE^.— A family of
Polypodiaceous Ferns, distinguished by the
delicacy of the structure of their leaves and
the composition of the sori or fruits. The
leaves are of the utmost simplicity of or-
ganization, consisting ordinarily of a single
layer of cellular tissue, traversed by scala-
rit'orm tubes constituting the veins. There
is no distinction of epidermis and paren-
chyma, nor are there stomata.

Gene)-a.

Trichomanes. Sporanges sessile around
the base of an exserted filiform column,
formed by the prolongation of a vein be-
yond the margin of the leaf, surrounded by

a cup-shaped indusium continuous with the
leaf (fig. 33i)).

HymenojdiiiUuyn. Sporanges sessile up
to tlie summit of a similarly formed column
projecting from the margin of the leaf, sub-
elevated, but not exserted beyond the indu-
sium, which is two-valved (tig. 340).

Fig. 339.

Fig. 340.

Trichomanes humile.

Hymeuophyllum biyalve

Fig. .?39. Fragment of a leaf, with sori.
Fig. 340. Ditto.

Magnified 10 diameters.

Loxosoma. Sporanges stalked, inserted
up to the summit of a subelevated exserted
column arising in a similar way within the
niargin of the leaf, surrounded by an indu-
sium, somewhat within the margins of the

Fig. 341.

Fig. 342.

Fig. 343.

Hymenophyllum cih'atum.

Fig. 341. Fragment of a leaf. Magn. 10 diama.
Fig. 342. Sorus with one valve removed Mang.

diams.
Fig. 343. SoruB. Magn. 20 diams.

40

HYMENOniYLLUM.

[ 406 ]

IIYPIIOMYCETES.

fissures between the teeth of the leaf, with
a truncated entire mouth ; annulus incom-
rlete.

HYMENOPHYL'LUM, Smith.— Filmy
Ferns. The tj'pical genus of Hymenophyl-
laceous Ferns, remarkable for their delicate
structure and often almost moss-like habit.
Two dwarf species are natives of Britain,
H. tunhrkhjense and H. Wilsoni. Numerous
tropical species (Hooker, Syn. 50).

HYMENOP'TEPtA.— An order of In-
sects, containing the Bees, &c.

IIYPERAM'MINA, Brady.— A tubular
and sandy Foramiuifer, irregular in exten-
sion and growth. (Brady, Ann. N. H. 1878,
i. 433 ; Mic. Jn. n. s. xix. 13.)

HYPERICUM, Linn. — Hinds points
out in the leaves of //. Androsa'inum, the
common Tutsan, and calijcinum, certain
dots containing active motile bodies {M.
M. Jn. xix. 2:!3).

HYPEROMYX'A, Corda, See Cheiro-

SPORA.

HYPH'EOTHBIX, Kiitz.— A genus of
OsciLLATORiACE^ (Confervoid Algae).

Char. Fil. simple, jointed, coloured, more
or less distinctly sheathed, tranquil ; fasci-
culate or densely united into a more or less
membranous non-radiate stratum (PL 52.

58 European species. In sprnigs, coating
"water-plants in pools ; on rocks, &c.

BiBL. Rabenhorst, Fl. Alg. ii. 75.

HYPHOMYCE'TES. — A section of
Fungi composed of microscopic plants,
growing as moulds over dead or living
organic substances. These are now con-
sidered to be conidiiferous conditions of
Ascomycetous Fungi ; but as they are in-
teresting and often very beautiful micro-
scopic objects, the original account is re-
tained here. The vegetative structure or
mycelium creeps over or among the struc-
tures infested as a collection of delicate,
simple or branched, continuous or septate
filamentous cells {flocci), and produces the
spores either on lateral pedicels (from which
they soon fall off, becoming intermingled
with the mycelium), or in heads at the
swollen or ramified extremities of usually
erect filaments (figs. 344, 345, .340, and 347).
These filamentous pedicels in most cases
exhibit a contraction just below the point
of origin of the spore, giving theni_ the
same appearance as the pedicels of basidio-
Bpores. The spores are round (PI. 20. fig.
15), oval (fig. ;}47 and PI. 20. figs. 5, 0),
spindle-shaped (Fusisi'ORiuii), spiral (He-

Fig. .344.

Fi?. 345.

Fig. 344. Cephalotheeimn roseum. Magn. 200 diams.
Pig. 345. Vex'ticillium nutans. Magn. 2uO diams.

licosporitjm), and isolated or connected
(tig. 340) in beaded lines (Pemcillium,
Aspergillus), or grouped in a stellate

Fig. 346.

Btysanus Ciiput-Meduaae.
Maguifled liUO diamtters.

form. In the Isariacei and Stilbacei the
erect pedicels are composed of a number of
conjoined filaments ; in the other families
the pedicels are simple filaments. Some
authors include among these plants the
Mucorini (Phycomycetes), regarding the
vesicular envelope of the spores there as a
mere veil, not a true cell producing the
spores in its interior. This fiimily is of
especifil interest from containing so many
moulds and mildews, and various parasi-
tical Fungi to which the' diseases of plants,
and in some cases of animals, have been
attributed. Further particulars respecting

IIYTIIOMYCETES.

[ 407 ]

IIYPNOIDE/E.

those will bo found uuder the Families, also

I'Alt.VSITIC EUKGI.

Fig-. 347.

Fig. 348.

Clonostachys Araucaria.
Fig. 347. Magn. 200 diams.
Fig. 348. A fertile branch. Magn. 400 diams.

Fig. 349.

Fig. 350.

Ceratocladium microspermum.
Fig. 349. Magnified 200 diams.
Fig. 350. Spores, magnified 400 diamfi.

Synopsis of the Families.

IsARiACEi. Eeceptacle clavately branched,
or assuming Ilyiuenomycetous forms, com-
posed of filaments closely attached in their
■whole length; spores simple, attached to
simple pedicels arismg in all parts (fig. 349).

Stilbacei. Receptacle wart-like or
clavate above, stalked below, composed of

filaments closely packed, coherent, termi-
nating singly in free subgelatiuous spores.

Dkmai'iei. IMyceliuni filamentous, spores
compound or simple, arising from the apices
of erect, solid, corticate, subopac^ue fila-
ments (fig. 346).

MucKDiNEs. Mycelium filamentous,
spores solitary, oi- crowded on articulatod
or branched tubidar and pellucid filaments
(figs. 344, 345), soon separating and min-
gling with the mycelium, or adherent in
chained rows.

Sepedoniei. Mycelium filamentous,
spores usually found heaped together resting
on the mycelium, and apparently springing
out of it directly. The spores are the
principal element in this Order, which ap-
proaches Coniomycetes.

IIYP'NEA, Lamouroux. — A genus of
Rhodymeniacefe (Florideous Algje), the
only British species of which, H. jnir^mras-
cens, is a common purplish pink feathered or
shrubby sea-weed, the lobes being cylindi-i-
cal, filiform, and cartilaginous, growing from
2" to 6" in height, with the filaments about
1'" in diam. On stones, rocks &c. between
tide-marks. The fructification consists of
coccidia, tubercles immersed in the ramuli,
each containing a mass of small spores ; and
tetrasporcs, immersed in the lesser branches,
of separate plants.

BiBL. Harvey, Mar. Alg. 130, pi. 16 D;
Fhyc. Brit. pi. 116 ; Enq. Bot. pi. 1243.

HYPNOl'DE^.— a' family of Pleuro-
carpous Mosses of large extent. Leaves
with the cells prosenchymatoiis, dense or
lax, smooth or papillose. Alar cells at the
bases of the leaves diverse : 1 , square, flatfish
or ventricosely impressed, pellucid or yel-
lowish, or fuscescent; 2, few, vesicular,
placed at the very base, of a delicate j^ellow
or hyaline ; 3, obsolete, scarcely any, placed
at the very base, fugacious, hyaline, vesi-
cular ; 4, many, square, in papillose leaves,
but mostly not very conspicuous. Leaves
0-5-nerved. Nerves binate, diverse : 1,
divergent from the base, distinct, very cal-
lous at the back of the leaf and prominent
in the form of a spine fiom the dorsal sur-
face ; 2, flattened down, scarcely caUously
prominent ; 3, in leaves where the alar cells
are vesicuhform, the nerves obsolete, indi-
cated by a pair of very short striae, mostly
inconspicuous.

British Genera.

a. Internal peristome tvithout interjwsed cilia.

Necket-a, Calyptra dimidiate. Peristome

HYPNUM.

[ 408 ]

HYPOGiEI.

double, single, or absent, the internal or the
external or both being occasionally obsolete.
External : sixteen equidistant or more or
less geminate teeth, lanceolate, trabeculate,
"with a longitudinal line, composed of a
double layer, arising below the orifice,
sometimes split into several irregular arms.
Internal : similar to the above, or capillary,
placed on a more or less exserted mem-
brane, conjoined by transverse appendages,
very often wholly or partly caucellate. No
interposed cilia.

PilotrivJium. Calyptra mitriform. Pe-
ristome, &c. as in Neckeea.

b. Internal peristo7ne ivith inteiyosed cilia.

Hookeria. Calyptra mitriform. Peri-
stome double ; external teeth lanceolate-
subulate, with a more or less broad longi-
tudinal median line, trabeculate ; internal
on a more or less deep keeled membrane,
subulate, scarcely ciliiform ; rudimentary
cilia interposed, hardly conspicuous, or,
more rarely, perfect.

Ilypnum. Calyptra dimidiate. Peri-
stome double. External teeth sixteen, lan-
ceolate, trabeculate, with a more or less
broad longitudinal line, more rarely a fis-
sure, with more or less crest-like prominent
trabeculfe within. Internal teeth on a
grooved reticulated projecting membrane,
lanceolate, articulated, grooved, solid or
perforated in the middle, or altogether
gaping and separating. Cilia one to four,
interposed, very often rudimentary.

IIYP'NUM, Dill.— A large genus of
Hypnoide?e (Pleurocarpous Mosses), here
including the species referred b}' modern
writers to Isothecium, Climacimn, Let:kea,
&c. Many of them are extremely common
in all woods, growing on trunks of trees,
banks, kc. ; others gTOw in water or in bogs,
&c. The distinctions of the species are
taken in gi-eat part from the forms &c. of
the leaves, which require the use of a
microscope for their accurate determination.

BiBL. AVilson, Ih-ijol. Br. 3.35 ; Hooker,
Br. Flora, vol. ii. pt. 1 ; Miiller, Syn. Mus-
corum.

IIYPO'CREA, Fr.— A genus of Sphfe-
riacei (Ascomycetous Fungi), with a hori-
zontal, sessile, or indistinct ileshy, mostly
coloured stroma, filiform asci, and simple
spores. The species of this genus, like
those of Tljipoxj/lon, as given by Fries, are
partly r(>ferred to Sphceria by other authors ;
the distinctions will be best explained by
taking' all these genera under Sph.^bia.

HYPO'DERAS, Frauenfeld.— A genus
of Acarea (Acarina). Numerous species,
occurring beneath the skin of birds, often
forming little cysts. — Giebel, Verh. zool.-
bot. Gescll. Wien, xiv. 385; Miu-ray, He.
Ent. 228 (figs.); Robertson, Jn. Mic. Soc.
vi. 201.

HYPODER'RIS, R. Brown.— A genus

Ficr. 351.

Hypoderris Browuii.

Borus with fringed indusium.

Magniiied 25 diameters.

of Dicksonieae (Polypodiaceous Ferasj,
with very prettily fringed indusia. Exotic.
(Hooker, »S'y«. 4().)
HYPOG^'L— A family of Gasteromy-

Fig. 352.

Hydnangium eandidiim.

Basidiospore8 upon the hymenium.

Magnified 400 diameters.

Fig. 353.

Hysterangium clatliroides.

Section of hymeniura with oval bnsidiospores.

Magnified 400 diameters.

cetous Fungi, characterized by their resem-
blance to the Truffles (Ascomycetes) in

IIYPOLEPIS.

[ 409 ]

nYSTERIUM.

crowing- uuderground, and bj^ tboiv fiesliy
mdehiscent recoptacle, wliicli is excavated
into sinuous cavities lined with basidio-
sjJores. which are sometimes smooth and
sometimes tuberculated (figs. 352, 358).

See Pi. 27. ti<r. 8.

BiBL. Tulasue, L. R. & C, Fmir/i Hypo-
gcri, Paris, 1851 ; Ann. Sc. N. 3 ser. xv. 2G7,
and A>in. N. H. 1851, vol. viii. 19; Berk.
Outl. 292.

HYPOLE'PIS, Bernh.— A genus of
Pteridece (Polypodiaceous Ferns), remark-
able as varjdng in the condition of the
iudusium so as to become uudistinguishable
from Polypodium. Seven species, tropical.
(Hoolv-er, Stin. 129.)

HYPOMY'CES, TuL— A genus of Py-
renomycetes (Ascomycetous Eungi), pro-
posed by Tulasne to include the coloured
species which are parasitic and spring fi-om
a thick floccose mycelium. Their conidia
are often extremely curious, and have been
referred to Sepeclotiiuvi, Asterophora, Dac-
tyliiim, kc. The species were formerly
included in Hypocrea.

BiBL. De Bary, Bot. Zeit. 1859, 385, 393 ;
Tul. Carp. iii. 38.

HYPOPTERYGIA'CE^.— A family of
Pleurocarpous Mosses with a peculiar ar-
rangement of the leaves, which are placed
in two opposite straight rows united on the
upper side of the stem, with a third median
row of smaller stipuliform leaves on the

Fig. 354.

Fig. 355.

Hypopterygium.
Fig. 354. Natural size.
Fig. 355. A leafy branch. Magnified 5 diams.

under side, bearing a resemblance to the in-
termediate leaves in Selagindla (figs. 354,

355). The cells of the leaves are parenchy-
matous and equal in all parts. The genera
are all exotic, viz. Hypoptcryyium, Cyatho-
phorum, and HelicophyUum.

HY'POPUS, Dug.— A formerly supposed
genus of Acarina, and family Acarea.

Char. Body ellipsoidal, coriaceous ; palpi
absent ; labium oblong, prolonged in the
form of a rostrum, and furnished with two
long anterior rigid setae ; the posterior pairs
of legs but little developed. The forms are
numerous, and are found as parasites upon
both animals and plants, as Arvicola (the
field-mouse), Bonibus (the humble-bee),
Musca (fly), some Myriapoda, and even
upon other Acarina; also upon ferns, &c.
Dujardiu supposed that they were young
forms of Gamasus ; Claparede that they
were the males of certain Acarea ; while
Megnin decides that they are the nymphs
of Acari (TyroyJyp/ius, Sec). They have
no mouth nor digestive organs ; but are
furnished with posterior ventral suckers.

PL 6. fig. 15 represents a Nyjiopus miis-
carum, which we found upon a house-fly
(J^Tusca clomestica).

BiBL. Duges, Ann. Sc. Ned. 2 ser. i. 20,
ii. 37 ; Gervais, Walckenaer's Arachn. iii,
265 ; Dujardin, Ajin. Sc. Nat. 3 ser. xii.
243 & 259 ; Claparede, Zeitschr. wiss, Zool.
186S, xviii. 445; Mmray, Ec. Ent. 231;
Megnin, Paras. 146.

HYPOTHECIUM.— The term applied
to the layer of cellular tissue, on which are
attached the thecoe or spore-sacs of the
fruits of the Lichens.

HYPOX'YLON, Fries. — A genus of
Sphaeriacei (Ascomycetous Fungi), distin-
guished by a sessile stroma, separate and
distinct from the matrix (see Sph^^ria).
The Hypoxyla of BuUiard with an erect
stroma belong to Xylaria.

HYSTE'RTUM, Tode.— A genus of Pha-
cidiacei (Ascomycetous Fungi), distin-
guished by the elliptical or elongated peri-

Fiff. 357.

Fig. 356.

Hystejiiim degenerans.

Fig. 356. Natural size.

Fig. 357. Perithecium. Magnified 10 diameters.

thecia (figs. 356, 357), bursting by a sim-
ple longitudinal slit. The species are nu-
merous, growing upon (usually dead) bark,

ICHNEUMON IDiE.

[ 410 ]

ILLOSPOrJUM.

steins and leaves of various plants. II. ru-
ffosmn has been placed by some authors
among liichens (as Oder/rapha macularis,
cpij^hei/a, Eug. I3ot.). It is common ou
smooth livhuj branches of oak and beech.
H. jmlicfire, II. Ituhi, H. Pini, and H. cul-
mi(/enu7n, the gvass-IIysteriimi and H.-folii-
colium, growing on leaves of hawthorn, ivy,
or oak, are common. The species with
septate spores (fig. 359) form the genus
Ilysteroyraphimn, Corda.

Fig. 358.

Fig. 359.

Fig. 358. Hysteriumfoliicolium^Hederae. Anascus
containing eipht spores, magnified 100
diameters; with loose spores, maguifled
200 diameters.

Fig. 359. Hysterium elongatum. Spores. Magnified
400 diameters.

BiBL. Berk. Ilooh. Br. Fl. vol. ii. pt. 2.
293; Ann. N. H. 1851, vii, 185; Fries,
Sum. Veyet. 3G8 ; Greville, Sc. Crypt. Ft.
pis. 24, 26, 72, 87, 88, 129 & 167.

I.

ICHNEUMON'IDyE.— A family of Hy-
menopterous Insects. The ovipositor is an
interesting microscopic object. (West-
wood, Insects, ii. 140.)

ICIITIIYDI'NA, Ehr.— A family of Ro-
tatoria.

Char. No carapace ; rotatory organ sin-
gle, continuous, not lobed nor divided at
the margin.

The rotatory organ is in the form of a
circle in Ptyyura and Glenophora ; in Ich-
thydium and C/ice/onotus it is long, baud-like,
and placed upon the ventral surface.

The family is thus divided: —

Eyes absent,

Kc) hairs present,

Tail-like foot simple and truncate... Tli/gura.

forked Ichthydium.

Having bristly hairs.

Tail simple, truncate Dasydytes.

Tail forked Chatonotus.

Eye single, frontal Sacculus.

Ej'estwo, frontal Glenophora.

Dujardin places Ivhfhydimn and Chccto-
no/wA' among the lufiisuria; and Ityyura
among his MelicertLua.

BiBL. Ehrenberg, Infus. 386 ; Dujardin,
Inf. ; Schultze, Mtill. Archiv, 185-3, 241.

ICIiTII YDTUM, Ehr.— A doubtfulgenus
of Rotatoria, of the family Ichthydina.

Clutr, Ej'es absent ; body without dorsal
hairs ; pediform tail forked ; locomotion
eftected by cilia placed upon the ventral
surface.

Dujardin places this genus among his
symmetrical Infusoria.

I.podura (PL 31. tig. 23). Body linear-
oblong, often slightly constricted near the
anterior turgid and sometimes trilobate
end ; foot short ; freshwater; length 1-140".

BiBL. Ehrenberg, Infus. p. .j88.

ICIITIIYOPHTHI'RI US, Fouquet.— A
S'enus of Holotrichous Infusoria.

Char. Subglobose ; with an anterior
suctorial disk, including converging setie.
Somewhat like Pantotrichnm.

I. muUlfiliis (PI. 53. fig. 19). Parasitic
on the trout, the loach, &c. ; forming milky
spots on the tins, giUs &c.; length 1-150".
(Kent, Inf 530.)

IDMO'NEA, Lamx.— A genus of Infun-
dibulate Cj'clostomatous Polyzoa, of tiie
family Tubuliporidffi.

Distinguished by the erect dichotomously
divided zoary ; and the tubular cells, on
one side only, in transverse rows, divided
into two sets by a median longitudinal line.

I. atlantica. Branches roundish, tapering
to a point ; cells four in each row, the
innermost tubes, considerably protruded.
Height 4-10". On zoophytes.

BiBL. Johnston, Br. Zooph. 278 ; Busk,
Br. Mus. Cat., Foss. Pol. Cray {Pal Soc.) ;
Ilincks, Pohjz. 450.

I'DUNA, CI. & Lachm.— A genus of In-
fusoria, fam. Ervilina.

Char. Those of Ervilina with a carapace,
the valves quite separate.

I. sulcata. Right valve with four raised
longitudinal ribs ; left valve plane and
smooth. Northern sea. Length 1-180".

BiBL. Clap, and Lachm. Infus. p. 283.

I'DYA, V\i\\v^YL= Ca)ithocanq>ttis, pt.,
Baird. I. furcatu=C. f. (l»rady, Copcp.,
Pay Soc. ii. 171 ).

ILIOl'SYL'LUS, Br. & Rob.— A genus
of Copepodous Entomostraca.

/. coriaceuSf in sea-miid. (Brady, Copep.
ii. 143.)

ILLICITOI. See Wintekeje.

ILLOSPORIUM, Mart.— A genus of
Stilbacei (Ilyphomycetous Fungi), mo.stly
rose-red gelatinous bodies growing upon

ILLUMINATION.

[ 411 ]

INFLAMMATION.

Lichens, described as consisting of irregular
spores, at tirst involved in a globule of
mucus, and aftenvards glued together in
simple mealy patches (tlieso plants seem
very obscure). Four species are described
as British :

/, roseum, Fr. (Grev. Sc. Crypt. Fl. pi. 51) .

I. carneum, Fr. (Corda, Ic. Fuihj. iii.

I. coralhnum, Rob. (Desmaz. Exsicc, no.
lool).

I. cocct)ieum, Fr. (Cord. /. c. fig. 3).

BiBL. Oj). cit. and Berk. Br. Flora, ii.
pt. 2, 328 ; Ann. N. II. 18-50, v. 460 ; Fries,
Sum. Veg. 482 ; Syst. Mi/c. iii. 259.

ILLUMINATION.— This has been
specially alluded to in the Introduction
(p. xxviii), and in the articles Angular

APERTUKE, DiATOMACEiE, POLARIZATION,

and Test-objects. But several papers
have been published in recent years, de-
scribing new and ingenious methods of
illuminating the finer and more difficult ob-
jects, to which we can only refer.

BiBL, Higgins, Qu. Alic. Jn. x. 150;
Abbe, M. M. Jn. xiii. 77 ; Smith, ib. 88 ;
AVeuham, ib. 156, & Entfl. Mechanic, 1877,
279 ; Whittell, ib. xiv. 109 ; Bramhall, ib.
xvi. 102 ; Osborne, ib. xvii. 179 ; Moore-
house, ib. xviii. 29 ; Woodward, ib. xviii.
01 ; Edmunds, ib. xviii. 78 ; Schulze, Jn.
Mic. Soc. 1878, 45,

ILYOBA'TES, G. O. Sara (=Krithe,
B., 0., & R.)' — -^ genus of Ostracoda (Ento-
mostraca), of the family Cytheridae. Lower
antennae 4-, upper 5-jointed, with the
last three j oints short and stout ; first two
pairs of feet three-jointed ; eyes wanting.

3 species. Recent in Norway, Britain,
Bay of Biscay. Fossil, Tertiary and Post-
tertiary, England.

BiBL. Brady, Crossky & Robertson,
Post-Tertiari/ Enfom. 1874, 184,

ILYOCRYP'TUS, G, O, Sars,— A genus
of Macrotrichidse (Eutomostraca).

1 species,

Britain, Russia, Germany, Sweden.

BiBL, Norman and Brady, Mo7i. Brit.
Entom., Nat. H. Tr. North, vol. i. 17.

IMPERFORA'TA,— A division of the
Foraminifera, characterized by the absence
of pseudopodial pores or tubules in the
ehell, which is either membranous (family
Gromidse), porcellaneous (fam. Miliolidae),
or arenaceous (fam. Lituolidse). (See

FottASlINIFERA.)

BiBL. Carpenter, Inirod. For. 02.

INAC'TIS, Kiitz.— A genus of Oscilla-
toriacete (Confervoid Algae),

Char. Filaments slieathed, indistinctly
jointed, parallel, sometimes dichotomous,
densely aggregatiid, and forming a pulvi-
nato hemisplierical frond, springing from a
substratum of Protococcus-like cells.

In pools, on other Alga3 ; on rocks, Sec.

3 species, with several varieties,

BiBL. Kiitzing, Phyc, 77 ; Rabenhorst,
Fl. Alq. ii. 159.

INDIA-RUBBER, or Caoutchouc—
This substance occurs naturally in globules
suspended in the milky juices of many
plants, especially of the Orders Euphorbia-
ceae, Urticacete, and Apocynacea? ; the
form of the globules is varied. In PI. 48,
fig. 23 is represented part of a milk- vessel of
Euphorbia antiquorian with fine caoutchouc
globides. When such milky juices are eva-
porated, the globules become blended into a
uniform elastic mass, the India-rubber.

Solution of caoutchouc is sometimes used
as a cement for closing glass cells ; but its
chief importance in this respect depends on
its forming a constituent of marine glue (see
Cements).

INDICATOR, QUEKETT'S.— Is a
small steel moveable hand placed j ust above
the diaphragm of the eye-piece, so as to point
to nearly the centre of the field.

INDIGO. — This well-known vegetable
substance is chiefly obtained from plants of
the genera Indigofera and Isatis, and Poly-
gonum tinctorium, but may be found in many
others.

It has also been found in human urine,
of which it is probably a normal consti-
tuent. Its best marked character is that of
subliming in flattened prisms and plates
(PI. 10. fig. 14).

Indigo is sometimes used as a colouring-
matter for injections, and is also very use-
ful for colouring the internal cavities of
Infusoria which swallow the gi-anules ;
also for rendering visible ciliary motion
(see Introduction, p. xxxvi), &c. The
simplest mode of employing it is to rub it
from a water-colour cake of indigo very
gently with a little water. The Infusoria
require to be left in the coloured mixture
some time ; and it is well to remove them
into clean water for examination.

Indigo-carmine forms the basis of some
excellent staining solutions.

BiBL, See Chemistry.

INFLAMMATION.— The phenomena of

INFLAMMATION".

[ 412 ]

INFLAMMATION.

inflammation are best studied in one of the
lower animals, as in the web of the frog's
foot, the mesentery of the frog, the tail of
the tadpole, or of the larva of the water-
newt {Triton), the process being excited by
the application of a hot needle, a solution
of common salt, ammonia, dilute spirit, or
volatile oil.

The principal phenomena are as fol-
lows : —

1. Changes in the blood-vessels and circu-
lation.

2. Exttdation of liquor sanguinis and mi-
gration of white blood-corjmscles ; and

3. Alterations in the nutrition of the in-
earned tissue.

1. The first eilect of irritation of the
mesentery (mere exposure to the air being
sufficient for the purpose) is to cause dila-
tation of the arteries, and subsequently tliat
of the veins. The dilatation of the arteries
commences at once, and is not preceded by
contraction. It gradually increases for
about twelve hours, and is associated at the
commencement of the process with an ac-
celeration in the flow of blood ; this, how-
ever, is soon followed by a considerable
retardation. These alterations in the rapi-
dity of the blood-flow, however, cannot be
owing to the increase in the calibre of the
vessels, which remain throughout dilated.

The retardation of the circulation usually
commences somewhat suddenly, and is first
observable in the veins. The rapidity of
the current varies, however, in different
vessels ; in some (both arteries and veins)
it may be more rapid, in others very slow,
and either oscillating to and fro, or even
completely stagnant. These differences may
occur in contiguous vessels. The capillaries
and small arteries often present at the same
time numerous irregular bulgings and con-
tractions.

As the circulation becomes slower, the
white blood-corpuscles (leucocytes) accu-
mulate in the veins. Their natural ten-
dency to adhere to the sides of the vessels
is increased, so that they may nearly fill the
tube. At the same time they exhibit active
movements, by means of which they pene-
trate the walls of the vessels and pass into
the surroimding tissues. The absolute
number of white blood-corpuscles may also
be increased o^^^ng to the irritation of the
lymphatic structures in the vicinity of the
inflamed tissue.

The red corpuscles also accumulate in the
capillaries. They adhere to one another

and to the sides of the vessels, and become
so closely packed that their outlines can
scarcely be distinguished. Increased ad-
hesiveness of the red corpuscles has long
been regarded as characteristic of inflam-
matory blood, by virtue of which they
exhibit a greater tendency to cohere in rolls
than in health.

The diminution in the rapidity of the
circulation, and the accumulation of the
blood-corpuscles in the vessels, is followed
by the complete stagnation of the current,
constituting the condition long known as
injlam matory stasis.

2. Another constituent of the inflamma-
tory process consists in the exudation of
liquor sanguinis and the migration of the
colourless blood-corpuscles.

The migration of the colourless blood-
corpuscles (leucocytes) through the walls of
the blood-vessels was first described by
Addison in 1842. This observer stated that
in inflammation, these corpuscles adhered
to the walls of the vessels and passed
through them into the surrounding tissues.
In 184G Waller more fully described the
same phenomenon. Both these observers
concluded that the escaped corpuscles
became pus-corpuscles. Cohnheim in 1867
brought the subject forward ; and to him
we owe most of our present knowledge
respecting it.

The migration may be observed in the
mesentery of a frog which has been pre-
viously paralyzed by the subcutaneous in-
jection of cm-are.

The colourless blood-corpuscles which
accumulate in large numbers, especially in
the veins, remain almost stationary against
the walls of the vessel, the blood-current
passing by them, although with much
diminished velocity. Those immediately
adjacent to the wall gradually sink into it,
and pass through it, between the epithelial
cells, into the surrounding tissue. In doiug
so they may be observed in the various
stages of their passage. At first small
button-shaped elevations are seen springing
from the outer wall of the vessel. These
gradually increase until they assume the
form of pear-shaped bodies, which still
adhere by their small ends to the vascular
wall. Ultimately the small pedicle of pro-
toplasm bv which they are attached gives
way and the passage is complete, the cor-
puscle remaining free outside the vessel.

The corpuscles having escaped from the
vessels into the surrounding tissues, coutiuue

IXFLAM:NLiTION.

[ 413 ]

INFLAMMATION.

to exhibit active movements. They may
multiply by diAisiou, and thus rapidly in-
crease in numbiT: this will be again referred
to when spealving of pus.

Not only is there a migration of colour-
less blood-corpuscles in iniiammatiou, but
the red corpuscles also pass through the
walls of the blood-vessels, though in less
considerable numbers ; and their transit is
mainly through the walls of the capillaries.
This passage of the red corpuscles takes
place in simple mechanical congestion ; and
it may be observed in the web of a frog in
which congestion has been artificially in-
duced by ligature of the femoral vein.

Associated with the passage of the blood-
corpuscles through the walls of the vessels,
is an exudation of the liquor sanguinis.
The exuded liquor sanguinis, which con-
stitutes the well-known inflammatory effu-
sion, differs from the liquid which tran-
sudes as the result of simple mechanical
congestion, inasmuch as it usually contains
a larger proportion of albumen and fibrine,
a proportion which increases with the inten-
sity of the inflammation. It also contains
an excess of phosphates and carbonates.

The most characteristic feature of inflam-
matory eftusion is the large number of cell-
structures W'hich it contains. These are in no
case generated spontaneously in the eflused
liquid. Most of them are migrated blood-
corpuscles ; and others are derived from the
proliferating elements of the original tissue.
The quantity and nature of the eflusion will
thus vary with the particular tissue in-
flamed, and with the severity of the in-
flammatory process. In non-vascular tissues,
as cai'tilage and the cornea, exudation can
only occur to a small extent from the neigh-
bouring vessels, and hence the effusion is
small in quantity. In dense organs, as the
liver and kidney, owing to the compactness
of the structure, a large amount of eftusion
is impossible ; and what there is, is so in-
termingled with the structural elements of
the organ, that it does not appear as an
independent material. In the kidney, it
escapes into the urinary tubes and so appears
in the urine. The effusion is most abundant,
and constitutes an important visible con-
stituent of the inflammatory process, in in-
flammation of those organs which possess
a lax structure and in which the vessels are
but little supported, as the lungs, and in
tissues which present a free surface, as mu-
cous and serous membranes.

3. The remaining constituent of the in-

flammatory process consists of an alteration
in the nutrition of the inflamed tissue. The
nutritive changes, although they may differ
according to the structure of the part, are
all characterized by an increase in the
nutritive activity of the cellular elements.
The nature of these nutritive changes has
for the most part been ascertained by the
investigation of tissues in the lower ani-
mals, in which inflammation has been arti-
ficially induced. In man the study of the
primary tissues is difficult, owing to the
fact that the process can rarely be observed
in its earher stages. The alteration in
nutrition, as already stated, is characterized
by an exaltation of the nutritive functions
of the cellular elements of the tissues in-
volved in the inflammatory process. This
is evidenced by an increase in the activity
of those elements which normally exhibit
active movements, as the amoeboid cells of
connective tissue and of the cornea. Cells
which, under normal circumstances, undergo
no alterations in form, and exhibit no active
movements, become active, sending out
processes and undergoing various alterations
in shape. This increase in the activity,
and variation in the form of the cells is in
most cases followed by enlargement and
division of their nuclei and protoplasm, and
thus by the formation of new cells.

The increased activity of the cellular
elements varies considerably in different
tissues, and even in the elements of the
same tissue. Some cells exhibit active
movements, and form new cells, much more
readily than others. Those tissues, for
example, which naturally maintain them-
selves by the multiplication of their ele-
ments, as the epithelial tissues, become
active veiy readily in inflammation, slight
degi-ees of irritation being sufficient to
cause in them rapid cell-proliferation.
This is seen in inflammation of mucous
membranes, and of the epidermis. In tis-
sues, on the other hand, whose elements
normally exhibit no tendency to multipli-
cation, as corhmon connective tissue, carti-
lage, and bone, active changes are much
less readily induced ; the cells are much
more stable, and multiply with fai* less
facility. Lastly, in the higher tissues the
stability of the elements reaches its maxi-
mum, and in nerve-cells no increase of
activity can be induced. Different cells in
the same tissue exhibit also different degrees
of stability. In common connective tissue
and the cornea, for example, the amoeboid

INFLAMMATION.

[ 414 ]

INFUSORIA.

cells are the least stable, and are the first
to multiply. Pos.sibly the age of the cells
may innuence tbeir tendency to become
active, the newer being less stable than the
older elements. In all cases, however, the
rapidity and extent of the proliferation are
in direct proportion to the intensity of the
inflammation. The earliest nutritive change
is thus one of cell-proliferation ; the subse-
sequent ones are characterized either by im-
pairment of nutrition and the degeneration
and death of the newly formed elements,
or by the develojtraent of these into a per-
manent tissue. The more intense the in-
flammation the greater is the rapidity of
the cell-proliferation, tlie more abortive are
the young cells, and the less is their ten-
dency to form a permanent tissue. In con-
nective tissues these changes in the cells
are necessarily accompanied by changes in
the intercellular substance. The latter are
for the most part characterized by softening.
In common connective tissue the fibres in
the first place become succulent and less
distinct, and ultimately they are completely
destroyed ; in cartilage the matrix softens
and liquefies ; in bone the lime-salts are
removed, the lamella) disappear, and the
osseous structure becomes converted into
medullary tissue. Hence the destructive
effect of the inflammatory process.

Those retrograde cells which undergo
fatty degeneration, are known as exudation
corpuscles (PI. 38. fig. 7).

The inflammatory exudation, consisting
of emisfrant cells, which often undergo fis-
eiparous multiphcation, of the proper cells
of the inflamed tissue, which undergo in-
crease of size and numbers, and of the fibri-
nated hquor sanguinis, may undergo reso-
lvfi<m, organization, suppu7-ation,iiiid organi-
zation after snjypuration : —

Resolution, by distribution of the emigrant
cells over a wider area, and their return into
the lymphatics, and by a process of fatty
degeneration of the cellular elements.

Organization, by the timely development
of blood-vessels, and the conversion of the
exudation into fibrillar connective tissue.
1'lie cells whicli are not devoted to the
formation of blood-vessels, grow spindle-
shaped, and are so closely packed that they
give rise to a new variety of tissue. It
forms cylindiioal or slightly flattened bun-
dles which intcrliice.

Suppuration. See Pus.

J>rr.L. AVorks on ^Tedicine; Tjcbert, Finis.
raihoL; \\'i^d\, I'atk. Jlist.; Imstev, I'atk.

An. ; Gluge, Atlas Path. An. ; Lister, Ifif.,
riiil. Trans. 1859; Oohnheim, Virehncs
ArcMv, xl. 1, and Entziindung, 1878 ;
Strieker, Qu. M. J. x. 242: Cornil and
Ilauvier, Hist. Path.; In flam., Holme's Sgst.
Surg. I. and Append.; Virchow, Cell. Path.;
Rin'dfleisch.Pff//;. Genvhd.lS7S;i}veei\,Path.

INFUXDIBULA'TA.— An order of Po-
lyzoa. (See Polyzga.)

INFUSO'RIA.— A class of Protozoa.

Char. Microscopic animals not furnished
with either vessels or nerves, but exhibiting
internal spherical cavities; motion effected
by means of cilia, or variable processes
formed of the substance of the bodj^, true
le^s being absent. (Body composed of pro-
teine compounds ; soluble in solution of
potash.)

Eveiy one who has examined with a
microscope a drop of water containing ani-
mal or vegetable matter which has been set
aside for a time, or a drop from any pool or
ditch, must have observed numerous minute
beings in active motion, i-esembling some of
those fio-ured in Pis. 30, .31, & 32 ; these are
Infusoria, or the animalcules of infusions.

Perhaps no question has been more dis-
cussed than that of the structure of the In-
fusoria. Ehrenberg regarded them as being
highly organized, and furnished with distinct
organs like the higher animals ; whilst some
more recent authors consider them as re-
presenting simply a nucleated cell. Unfor-
tunately the facts are not accordant with
either of these views, and the question must
be considered as still sub judiec.

The more or less flexible body of the Infu-
soria is usually covered with vibratile cilia,
which appear to spring from a cuticle. They
are sometimes collected in a circle around
an opening or mouth, which leads to a gullet
terminating in the soft sarcode of the centre
of the body. This central portion of the
granular and otherwise structureless sarcode
is surrounded by a denser or cortical layer,
which underlies also the cuticle. In the
cortical layer are the vacuoles and the nu-
cleus and nucleolus ; whilst in the inner
mass are the spaces which are produced by
the ingestion of food and water, and which
have been termed stomachs, whence the
fornier name, the Polggastriea. There is a
rotatory movement of the soft sarcode sur-
rounding these digestive spaces, which
causes them to change their positions before
they disappear. The animalcule moves
some of its cilia voluntarily ; others appear
to be in constant movement, and they are

INFUSORIA.

[ 415 ]

INFUSORIA.

the principal locomotive and ingestive or-
pjins. The diversity of shape and structure
is very great amongst the Infusoria ; and it
is therefore necessary to consider the details
of the different p;u'ts composing them sepa-
rately and in order.

Intef/itmeiif. — Tlie bodies of Infusoria con-
sist of sarcode, of which the outer layer
possesses usually considerably more consist-
ence than the internal portion. Cohn de-
monstrated the presence of this pi^Uicular
layer in Paramecium by the addition of
alcohol, and noticed that the softer tissues
remained united to it by a process in one
place only, whei'e the short gullet, which is
also lined by a continuation of the external
tissue, dips down and merges into them.
This hard transparent pellicle or cuticle is
elastic, but its contractiUty is doubted ; and
it often becomes visible when the Infusoria
are kept in a small quantity of water upon
a slide, the globules of sarcode which escape
from rupture of the body carrying it before
them. It is frequently beautifully marked
with minute depressions (PI. 32. fig. 1), re-
gularly arranged, and from each of which a
cilium arises. This cuticle must be regarded
as a secretion from the outer or cortical
layer of the sarcode ; and it is by no means
improbable that Leydig's assertion that it
arises from a layer of extremely dehcate
and small cells will turn out to be con-ect.

Many Infusoria ha^^e a carapace or lorica,
which is in some soft and in others very hai'd ;
the relation of the hard carapace to the pelli-
cular layer is not, however, very distinctly
known. The carapace is often not adherent to
the body of the Infusoria, but forms a kind of
sheath for the protection of the soft tissues ;
or it may form one or two valves which are
more or less completely soldered together.
These tests are thicker and less elastic than
the cuticle ; and the peduncles which sup-
poi*t many species of Infusoria, and which
in some instances are hollow and contain a
contractile sarcode by which they are
secreted, belong to the same kind of struc-
tures. Beneath the pellicular layer, the
substance of the body frequently appears
thicker, although no distinct layer can be
separated; and it is doubtful whether the
markings are situated in the outer coat, or
whether the latter derives them from being
moulded upon the inner coat, to which
they may properly belong.

This cortical layer (parenchyma of Cla-
parede and Lachmann), as it is called, is
firmer than the central and more difHuent

sarcode, with which it is continuous inter-
nally. ^ It is almost homogeneous ; but an
indelinite and irregular reticulation and
fibrillation may be observed in many species,
and especially in the Vorticellae, close to
the insertion of the peduncle, with whose
contractile fibre it is continuous. Tho
fibrils and the so-called muscles of the
peduncle are composed of sarcode, which
has no definite structure, and which is here
and there faintly granular ; but they possess
the power of contracting more or less.
Besides these, there are the minute gra-
nule-looking cells immediately under the
pellicle (which haye already been noticed),
the contractile vesicles or spaces with their
ramifications, the nucleus and nucleolus,
and sometimes chlorophyll-gi-auules. When
present, the brightly coloured pigment-
spots, the so-called eyes, appear to be pro-
duced in this layer ; and the whole of the
cilia are continuations of it. Wright has
observed amoeboid movements in this layer.
The portion of the body which is surrounded
by and more or less continuous with the cor-
tical layer, and which is subject to rotation,
is softer and often contains granules and
corpuscles resembling fat-cells. The mouth
and gullet open into this central sarcode;
and the anus, when it exists, leads from
it. Numerous digestive vacuoles are ob-
served in this watery sarcode, which often
presents the appearance of being faintly di-
vided by films and fibres of less difiluent
protoplasm.

The existence of the outermost coat or
pellicle is demonstrated by the phenomenon
of ecdysis, which occurs in certain species.
But this does not exist in all cases ; for in
some Infusoria the body adlieres readily to
the glass of the slide on which it is viewed
under the microscope, and is torn xip into
fragments in the endeavour to free itself.

The cortical layer of some species pro-
duces trichocj'sts or thread-cells. These
are fusiform, colourless, and transparent
bodies, 1-2500" in length, aiTanged on the
outside of the body and perpendicularly
to it. Irritation of the surface causes them
to be transformed into long filaments ; and
they are more or less like the thread-cells
of the Polypes: but they are developed
within the cortical layer, and not as cells on
its surface.

Minute amylaceous crystalloids, coloured
blue with iodine, have "^ been observed in
Strinnbidium.

Locomotive organs. — No distinct muscular

INFUSORIA.

[ 416 ]

TNFUSOEIA.

structure can be detected in the Infusoria,
but a contractile power is possessed by the
general substance of the body. In Vorticella
(PI. 32. figs. 21 a & 20) and some others, the
contractile substance is prolonged through
the hoUow pedicle, thus forming a spurious
muscular baud.

The other directly or indirectly locomo-
tive organs are thus distinguished. 1, cilia:
these are the most common, and form the
fine, short, very transparent, hair-like fila-
ments projecting from the surface. In
some they entirely cover the surface, whilst
in others they are arranged in one or more
rows round the mouth or upon the ventral
sm-face, &c., as described under the genera.
During life they are seen actively vibrating ;
and in some their motion appears constant ;
whilst in others it is interrupted at inter-
vals, apparently under the influence of a
will. They are most distinctly seen when
the Infusoria are dried (see Cilia). 2, fla-
gelliform filaments (PI. 31. fig. 59), which
are long anterior cilia, the ends alone being
vibratory and movable in all directions ;
there are usually one or two only. 3, re-
tracting ciha or filaments (PI. 30. fig. 12,
18 a ; PI. 31. fig. 17) : these are single, long,
flexuous, and directed backwards ; they fre-
quently become adherent to the slide, and
produce a sudden, backward motion of the
animal. 4, setge or bristles (PI. 31. fig. 53) :
these are rigid, filiform, straight, and mo-
vable, but not vibratile, and are sometimes
provided with a bulb at the base ; they can
be slowly raised or depressed, and serve for
support, walking, or climbing. 5, styles
(PI. 32. fig. 17) are thick, straight, very
movable setaj, without bulbs, sometimes
having setiform branches ; they neither ro-
tate nor vibrate. 6, uncini or hooks (PI. 50.
fig. 13) are short, thick, curved, sometimes
cleft setfe, serving for prehension, climbing,
or creeping, and are bidbous and usually
very thick at the base.

The long straight cirri of Halteria (PI. 50.
fix. 12), by which the saltation of these
Infusoria is produced, probably come under
the fifth series ; but the foot of such genera
as Dysteria (ErviUa, Duj.) (PI. 30. fig. 52),
which is used for locomotion, and also as a
peduncle, is the homologue of the contractile
sai'code in the hollow peduncle of VorticeUa.

The flageUum of a marine Ceratium which
was observed by Claparede, suddenly disap-
peared during a rapid contraction. _ It re-
tracted into a spherical cavity, which was
placed close to its point of insertion.

Nervous system. — Xone has been disco-
vered. In the naked Infusoria, the sense of
touch is difiUsed throughout the substance
of the body. In others, it is particularly
developed in the snout-like appendages of
the body, and in the longer cilia, sette, &c.
The Infusoria are probably all sensible to
light ; and many of them exhibit, near the
anterior part of the body, one or more
coloured (mostly red) specks, which have
been regarded as eyes; but they contain
no distinguishable cornea, nor lens, nor are
they connected with any appreciable sub-
stance comparable to nervous matter.

The pigment-spot is composed of a col-
lection of minute and highly refracting
granules, and in some species it is associ-
ated with Lieberkiihn's " watchglass-like
organ." This is a very minute, transparent,
colourless and hard part of the cortical
layer, which has its convex side towards the
pigment-spot and the concave towards the
head ; but it is not dependent on the pre-
sence of the pigment, for some species
possess it which have no pigment-spot, and
vice versa. Similar specks occur in the same
situation in the spores of many Algfe ; more-
over the eye-specks are most distinct in those
genera which are doubtful Infusoria. Hence
it may be denied that they represent eyes ;
yet they bear considerable resemblance to
the eyes of the Rotatoria and some Anne-
lida ; so that their true nature must be con-
sidered doubtful.

Digestive system. — On attentively exami-
ning Infusoria under a high power (1-4 to
1-8), a number of rounded spots are gene-
rally visible in the substance of the body ;
they are sometimes filled with a whitish
granular matter ; at others they contain
Desmidiacese, Diatomacepe, or other AlgiB
or bodies existing in the surrounding water.
These have been called gastric vesicles, cells,
spaces, vacuoles, or sacculi. They are only
visible from their contents, and no mem-
brane can be distinguished in them. If a
little indigo or carmine be added to the
water containing the Infusoria, these cavi-
ties will soon become filled and will be
rendered very distinct ; in the Plates they
are represented as fiUed with these pig-
ments.

On attentively watching them, they wiU
appear to move around the body of the ani-
malcule, sometimes two of them appearing
to become fused into each other, or the con-
tents of one to pass into another. Finally,
the pigment will be seen to escape at some

INFUSORIA.

[ 417 ]

INFUSOKIA.

part of the surface of the body, when the
spots will vanish.

Different views have been entertained in
regard to the nature of these spots or cavi-
ties. By the older observers, they were
regarded as interiial cavities into which
water was admitted with any particles acci-
dentally suspended in it, fonniug a means
of bringing a greater extent of surface of
the substance of the animalcule into con-
tact with the water, and thus aiding in
resjnration.

Ehrenberg regarded them as dilated caeca,
or portions of an alimentary canal (PL 31.
fig. 88 a) ; whilst Dujardiu considered them
vacuoles arising in the same manner as
those found in sarcode from whatever
source derived; others have viewed them
as cells floating loosely within the body.
Most observers deny tliat they are portions
of an alimentary' canal, and that such canal
exists, but adopt the opinion that they are
cavities irregularly formed in the substance
of the body by the introduction of the
foreign matters, which are urged through it
by its contractions, or moved onwards by its
circulation. They are certainly not cells ;
otherwise they could not so readily admit
particles of colouring-matter, &c., nor could
their contents become fused together, as is
sometimes seen to occur. Thej^ do not
appear to be simply vacuoles filled in the
ordinary manner by the surrounding liquid,
because the pigment is accumulated in them
in greater proportion than it exists in the
liquid. In many Infusoria, the particles
are admitted at a definite orifice, representing
a mouth ; this is round or oval, sometimes
situated at the anterior end of the body,
sometimes more posteriorly or even at the
commencement of the posterior third of the
body ; and it is generally indicated by a
circle, fringe, or some other definite arrange-
ment of the cilia, which bring the particles
towards it. Sometimes a distinct ossophagus
lined with cilia leads to the internal sub-
stance, or to the sacculi. The course which
the particles (apparently in gastric cavities)
take is usually irregular, but sometimes
tolerably definite, down one side of the
body and up the opposite. The manner in
which the undigested particles are evacuated
is also an unsettled question ; for whilst
Ehrenberg and, more recently, Lachmann
admit either the existence of a distinct ex-
cretory orifice, or evacuation by the mouth,
other authors assert that these particles
may be evacuated at any part of the surface

of the body. According to the later obser-
vations of Lachmann, the cavity of the
body of the Infusoria represents a large
digestive cavity, as in Hydra, the contents
constituting chyme, and there is a distinct
mouth and anus.

The question then must remain whether
there is a distinct alimentary canal, the
walls of which are invisible on account of
their extreme delicacy, or whether the par-
ticles drawn in by the cilia are urged at
random through the substance of the body.
The fact that distinct walls cannot be de-
tected, is of no great weight in opposition
to the former view, because the radiate
contractile vesicles of Parainecium exhibit
no walls, and are quite invisible when con-
tracted ; and the excretory vessels of Din
stoma, although having distinct walls, are
seen to contract and then to vanish com-
pletel}' (Van Benedeu).

It may be easily ascertained by experi-
ment that some Infusoria will imbibe bi-
sulphuret of mercury as readily as indigo or
other matters, and thus would appear to be
entirely deprived of any selecting power
governed by a sense of taste; but some
kinds would seem to have a sense of taste :
Coleps, for instance, greedily devom-s the
substance of crushed Entumostraca and
their ova, becoming greatly deformed in the
operation.

The vacuoles or digestive cavities are
frequently ver}^ distinct when the ani-
malcules are dead, and especiall}^ when
dried. If the animalcules be fed with co-
louring-matter, on drying them, the vactioles
thus rendered distinct wUl be found to con-
tain the pigment, which is in favour of
Dujardin's view.

Surrounding the mouth in some Infu-
soria, as Nassula, Prorodon, Chilodon, and
CJdamidodun, is a horny cylinder of rod-like
bodies called teeth (PI. 30. tigs. 27 a, h, 29 ;
PL 31. figs. 40, 45, 72) : they do not appear
to exert any triturating power ; and their
true signification, is unknown. In some In-
fusoria an oesophagus is also present, as in
VorticeUa, Carchesium, Epistylis, Oxytricha,
&c., consisting of a mostly funnel-shaped
tube, often lined with cilia.

A coloured gastric juice has been de-
scribed by Ehrenberg as existing in the
gastric cavities. The colour, however, has
been accounted for by Siebold as produced
by refraction and the presence of aggrega-
tions of pigment-granules, mistaken for gas-
tric cavities. This explanation we believe

2e

IKFUSOEIA.

[ 418 ]

INFUSORIA.

to be inadmissible; and in some instances,
at least (PL 30. fig. 19), the reddish-violet
colour is real, and arises from the presence
of solution of the colouring-matter of Oscil-
lutorice, which is often different by reflected
and transmitted light.

The particles of solid matter forming the
food of the Infusoria, are usually drawn to
the oral orifice by tlie action of the cilia.
The manner in which Actinophnjs takes its
food is described under that head ; but, from
Lachmann's observations, the rays of Aci-
netu ai'e hollow suctorial organs.

In many of the organisms included among
the Infusoria, the food-particles are ingested
at any parts of the entire surface, or at
certain parts only, no mouth being present.
Circtilaf.ing si/stetn. — On closely watching
almost any of the Infusoria, minute, mostly
rounded, clear spots are seen in the sub-
stance of the body, disappearing and reap-
pearing at pretty regular intervals. These
are the contractile vesicles ; they are of var-
able size, but about that of the gastric
cavities. The nature of their contents,
which is a colourless liquid, is doubtful.
Dujardin regards it as consisting of water,
and as existing in vacuoles similar to the
vacuoles or gastric cavities ; whilst Siebold
and others find here a kind of rudimentary
circulation of a nutritive fluid, comparable
to the circulation of the blood. In certain
Infusoria, as Pararnecimn (PI. 31. fig. 56),
this phenomenon is observed to take place
between a central rounded and several
elongated and radiating cavities, and the
liquid contents are seen to be propelled
from the former into the latter, and vice
versa. These contractile or pulsating vesi-
cles or spaces, as they are called, never
contain foreign particles ; they are tolerably
constant in position in the same species of
Infusoria ; and they do not rotate nor move
like the gastric cavities ; all of which facts
are opposed to the notion of identity with
the latter. The contracting vesicles of
some species open externally through a
canal ; and in others a long internal vessel is
continuous with them. They are found in
some Algaj, as Volvox, Chlamidomonas,
Gonivm, Si/ncrypta, as in Dinuhnjon and
Eiic/lena, wbich would negative their relation
to an animal circulation. Kent, however,
considers the presence or absence of the
contractile vesicle a ready means of dis-
tinguishing unicellular animal from vege-
table organisms. Lieberkiihn and Lach-
mann describe distinct vascular branches

arising from the contractile vesicles, not
penetrating the internal sarcode of the body.
Another kind of circulation takes place
in some of the larger Infusoria. This is a
rotation of the mass of the internal sub-
stance of the body. It has been observed
in Parnniecium, but only in those specimens
having green coi-puscles imbedded in the
outer coat.

When almost any of the Infusoria are
allowed to remain upon a slide until most
of the water has evaporated, roimded and
somewhat highly retractive globules will
become evident at their margins (PI. 32.
fig. 2 a) ; these consist of the semifluid
gelatinous sarcode forming the interior of
the body, and they possess a remarkable
tendency to the formation of vacuoles or
cavities within them, which apparently be-
come filled with tbe surrounding water.
This fact is perhaps the strongest in favour
of the formation of the gastric cavities and
contractile vesicles within the body of the
living animals in the same manner as sup-
posed by Dujardin ; which, however, is
opposed, in the case of the contractile vesi-
cles, by their tolerably constantly uniform
position, and especially their remarkable
form (as in the stellate vesicles of Parame-
cium itc, PI. 31. tig. 56), and the manner
in which the contents in tlie latter instance
are propelled from one to the other, or from
the radiate to the rounded vesicles.

Nucleus. — In tlie substance of the bodies
of most of the Infusoria may be perceived a
solid granidar-looking body, of variable
form, mostlv rounded, elonsrate, or curved
(PI. 30. tig."5o ; PL 31. figs.^37, 56; PL 32.
fig. 26), sometimes branched (PL 32. fig. 25),
which those who regard the Infusoria as
consisting of simple cells consider a true
nucleus, whilst Ehrenberg regarded it as a
testis.

Nucleolus. —This is usually a small body,
in or upon the nucleus, and with a high
refractive power.

Propagation and reproduction. — The In-
fusoria increase in numbers by the following
methods: — 1. Fission or self-divLsion. This
occurs in (o) the perfect form of the animal-
cule, and (h) after it has become encysted.
2. Gemmation or budding. 3. Conjugation.

1. Fission or self-division. — {a.) Sponta-
neous division is either longitudinal (PL 32.
fig. 37) or transverse (fig. 3S). In both, the
nucleus undergoes division, as well ns the
body. In the longitudinal division the pro-
cess commences at one end of the body,

INFUSORIA.

[ 419 ]

INFUSORIA.

from which the cilia usually are retracted
or di:>api3ear ; a notch is first perceived,
which afterwards becomes deeper, until the
body is completely cleft; the two halves
then acquire cilia, and assume the functions
of perfect animals. In the transverse divi-
sion, a median constriction appears tirst,
followed by perfect separation, as in the
last. During these processes of division,
the animals sometimes continue their move-
ments as usual ; at others this is more or
less interfered with. In Vorticella (PI. 32.
fig. 21 a), in which the process of longitu-
dinal division may be conveniently watched
on account of the comparative fixure of the
animals by a pedicel, when the division is
nearl}' completed a ring of ciUa is formed
near the attached end of the body, by the
movements of which the new Forticella is
separated from the parent. The process is
completed in about an hour.

Claparede and Lachmann state that the
first process in the spontaneous di\ision of
Vorticella is the development of a fresh
mouth-circle of cilia and a second contrac-
tile vesicle ; then a partial division occurs,
which is followed by fission of the nucleus
and final separation of the two animalcules.

(b.) Fission as part of an encysting pro-
cess.— Many of the Infusoria are observed to
alter their form at certain periods, become
rounded, lose or retract their cilia (PI. 32.
fig. 27), and to secrete aU over their surface
gelatinous matter, forming a coat or cyst
enclosing them. While thus encysted, the
substance cf the body becomes divided, and
gives origin to a number of germs, which
are discharged by the bursting of the cyst
(PI. 32. fig. 34). They do not then resemble
the parent, but are gradually developed,
during ordinary growth, into its form.
In some cases the progeny or brood become
individually encysted within the parent
cyst ; it appears, however, that they are not
discharged in this condition, but escape
first from their own cyst and then from
the parent, in which they leave their own
exuviae. Stein thinks that it was such
broods that Ehrenberg mistook for the re-
sults of the increase by diffluence.

In Trichoda lynceus the encysting process
appears subservient to a kind of metamor-
phosis of the individual, the animalcule
which emerges from the cyst having cha-
racters in many respects different fmrn the
Trichoda, but no multiplication is effected
either by subdivision or gemmation. The
late Jules Haime described this multi-

plication by fission, the encysting of ova of
the separate Trichoda, and the subsequent
escape of a diffcn-ntly sliaped creature,
which became gradually developed into a
form like Asjndisca.

2. Gemmation is not a general proces in
the Infusoria. It is well seen in P'orticella
(PI. 32. fig. 2G). The buds arise from near
the posterior end of the body, and, when
fully developed, Hberate themselves by the
formation of a posterior ring of cUia, aa
above mentioned.

3. Conjugation, — Balbiani supposed that
male and female organs existed in many
Infusoria, the former being represented by
the nucleolus, which resolved itself into sper-
matozoa ; the latter by the nucleus, which
after sexual conjugation became converted
into ova. Later researches, however, show
that the conjugation is an ordinary fusion
of the structures of two individuals without
sexual relations. In the conjugating con-
dition, the animalcules often closelyresenible
those undergoing division. Thus Parame-
cium aureUa multiplies to a great extent
by self-fission, but only to a definite extent,
for sooner or later they conjugate. They
assemble upon certain parts of the con-
taining vessel, and soon become coupled in
pairs. They are closely adherent to each
other, with their similar extremities turned
in the same direction and their mouths
closely applied. While thus conjugated,
they continue moving with agility in the
liquid, turning round and round upon their
axes ; but those which, like Stentor, are
attached by a footstalk remain almost
motionless. The conjugation lasts for five
or six days. It is also stated that reproduc-
tion is etfected by the breaking up of the
nucleus into fragments which subsequently
become developed into the parental form.

The metamorphosis of the Infusoria has
been noticed above ; but there is another
method by which the individual is pre-
served for a time, the encysting process
icithout fission. Many Infusoria at certain
times undergo an encysting process, which
apparently serves as a provision under cir-
cumstances which do not permit the con-
tinuance of their ordinary vital activity.
The movements of the Infusoria diminish
in vivacity, and the cilia are either lost or
retracted ; the surface of the body pours
out a secretion which hardens around it
and the animalcule lives on and rotates
within its cyst until the time for its escape
arrives.

2e2

INFUSOEIA.

[ 420 ]

INFUSORIA.

Some Infusoria live in very briny ■water ;
and some can exist at a temperature of
120° Falir.; but their numbers diminish -with
the cold of winter, although a few can exist
when frozen in ice. Hardy as they are as
a class, it is therefore very remarkable to
witness the succession and disappearance of
ditierent genera during a comparatively
short time in infusions and natural waters.

Diffusion, ^-c. — When we consider that
the multiplication of the Infusoria by divi-
sion takes places according to a geometrical
progression, also that they need only be-
come encysted to produce swarms of germs,
we can ea-ily understand their rapid pro-
pagation in liquids ; when also they will
resist a degree of cold =8° F., and an ele-
vated temperature of 2t)0° F., or even de-
siccation, without destruction, and when
their minute size is added, we can readily
understand their almost universal diffusion.

As we have stated, a drop of water can
scarcely be found which does not contain
some Infusoria. Many of them wall only
live in fresh or sweet water, whilst others
are found only in decomposing and even
putrid water containing clecomposing ani-
mal and vegetable substances; others,
again, are only met with in salt or brackish
water. Those existing in fresh water may
be collected in ordinary wide - mouthed
bottles, a drop of which may be removed
by the dipping-tube ; any individual one
perceptible to the eye may be withdrawn
by the same means. Their natural move-
ments are best watched in the live-box ;
but these movements greatly interfere with
the observance of the contractile vesicles
and general minute structure, which is best
seen when they are simply confined be-
tween the slide and cover, in a small
quantity of water. A good plan for arrest-
ing their motions is that of warming the
slide containing thorn over a caudle or lamp
for a short time. Many Infusoria live only
in particular kinds of infusions, just as cer-
tain plants live only upon particular kir.ds
of soil ; and these infusions should be pre-
pared by adding cold fresh water to the
vegetable or animal subtances (the water
being in considerable excess), and allowing
the mixture to remain for a time. Even in
infu.-ions of many powerful poisons, as of
Nux vomica, Cevadilla, &c., they will not
be found absent; and Dujardin noticed
thattheirdevelopment was greatly promoted
by the addition of certain salts to the solu-
tious, as phosphate and carbonate of soda,

phosphate, nitrate, and oxalate of ammonia
(really, the more recently so-called Pasteur's
liquid) ; and this author was inclined to
believe that some of these salts become de-
composed in the presence of the organic
matters, yielding nitrogen to the Infusoria ;
he also states that oxalate of ammonia dis-
appears entirely under these circumstances.
The following are the most common In-
fusoria found in natural waters or infusions
of vegetable or animal matters : —

AmpMleptus fasciola. Monas guttula.

Budo saltans. tertno.

socialis. Oxytricha iieUioneUa,

Chilvdon cucullulus. Paramecium aurelia,

CJiilomonas parame- chrysalis.

ciiim. colpoda.

Chlamidomonas pul- milium.

visculns. Polytoma tivella.

Coleps liirtus. Stylonichiapusf.idata.

Colpoda cxcidlus. mytihis.

Cyclidium ylaucoma. Trachdins lamella.

Euplotes cliaron. Tricltoda pura.

Glaucoma scintillans. TricJiodina grandi-
Leitcophrys carnium. nella.

I'yriformis. Uvella ylaucoma.

Monas crepusculum. Vorticclla convallaria.
yliscens. microstoma.

Some of the Infusoria are phosphorescent,
and impart a luminous property to sea-
water. This has been distinctly observed
in the following species : — Proroccntrnm
micans; Peridinium michaelis, P. micans,
P. fusus, p. furca, and P. acuminatum,
SynchcBta haltica, and a doubtful species of
Stent or.

Slender needle-like crystals of sulphate
of lime have been observed affixed to the
bodies of the Infusoria, probably derived
from the water in which they live.

The Infusoria are difficult of preserva-
tion. Some of them will exhibit their cha-
racters when dried, the cilia and vacimles
remaining very distinct, as also the striae
upon the integument. Others are but little
changed by a concentrated solution of chlo-
ride of calcium, or dilute glycerine. Solu-
tion of chromic acid or of bichloride of mer-
cury will answer with some of them, al-
though they are rendered somewhat opaque
by these reagents, which is sometimes an
advantage where they are naturally very
transparent. Osmic acid has been found
very useful in killing them so instan-
taneously, that the cilia remain as in
the living state. A saturated solution of
iodine in iodide of potassium acts like o^rmic

INFUSORIA.

[ 421 ]

INFUSORIA,

acid. The juice of the common horse-shoe
geranium is a very old agent for elFecting
the same purpose (Kent). The various
colouring- matters — eosine, haematoxyhue,
aniUne, picrocarmine, kc. — serve to distin-
guish the nuclei &c.

The chemical properties of the sarcode
or protoplasm of the lower animals and
plants, are very important to be noted. For
although proteine matter exists in both,
yet in the vegetable forms this is in very
small proportion, and tlie motile power is
correspondingly feeble. Solution of potash or
ammonia dissolves the proteine matter, and
as the animal organisms are almost entirely
compos.'d of this, their bodies vanish; while
in the case of vegetable organisms, the pre-
ponderating cellulose matters remain, the
organism apparently undergoing no change.
Probably if this test were applied to the
Flagellate forms, few would be left among
the Infusoria ; and it should be used in all
cases.

The systematic arrangement of the Infu-
soria is in an unsettled state. The charac-
ters of the genera and species laid down by
Ehrenberg were mostly founded upon analo-
gies rather than upon observation. Those
proposed by Dujardin were far more accor-

dant with observation ; but unfortunately
this author so altered the names proposed
by Ehrenberg, raking up old and long-for-
gotten names, which are moreover often
doubtfully identical with those for which
they are substituted, and sometimes using
similar names for totally different genera
and species — that great confusion was pro-
duced, and the two systems are not recon-
cilable.

The later system of Claparede and Lach-
mann was a great improvement upon the
former ones ; and this has been strengthened
and improved by those of Stein and Kent.
The standard work of the latter is replete
with laborious research ; and contains de-
scriptions and figures of all the species.

In descriptions of genera and species the
anterior part of the body is that near which
the eye-specks are situated, and which is di-
rected forwards ; the surface towards which
the eye-specks are nearest forms the back
or dorsal surface. A narrowing of the body
posteriorly, so as to give rise to a prolonga-
tion, forms a tail ; and an anterior prolon-
gation of the dorsal surface is described as
a forehead or upper lip, according to its
situation.

According to the system of Claparede and Lachmann, the Infusoria are arranged as follows : —

I. CiLIATA.

SucroRiA.

rx a 11 < Cilia also present '. Order III. Cilio-plaGELLATA,

One or more fiagella ^ j^^ ^j^^ i Order IV. Flagellata.

■NT^ florroiiMvn / Cilia or brlstlcs 111 the adult ; no suckers Order

nonageiium 1 Ho cilia in the adult ; suckers present Order II

Mouth and oeso-
phagus open in
repose, the latter
ciliated, neither
dilatable

Mouth and oeso-
phagus very dila-
table ; oesopha- '
gus not ciliated .

Order I. Ciliata.

'Mouth and anus in a common fossa. Buccal spiral deiiotrope 1.

( Buccal cilia f ^? °''^'','' locomotive organs than the

2v 1 buccal oilia 2.

•' L Crawling locomotion 3.

Buccal spiral laeo-"] /Body bell-shaped, several rows of

I I buccal cilia 4.

( Cilia all over ■< Buccal spiral f Buccal cilia strong-
forming one-! est 5.

I turn only ... (.No buccal spiral 6.

C rAfoot 7.

I Body entirely or mostly ciliated •••■{ ]Vo f^^t j ^'o carapace 8.

I [ ■" (A carapace ; 9.

^Body glabrous, one row of cilia around the mouth 10.

Mouth and anus not i
in a common fossa. J

trope

Fam. VorticelUna.

Fam. TJrocentrina.
Fam. Oxytrichina.

Fam. Tintinnodea.

Fam. Sursarina.
Fam. Colpodea.
Fam. Di/sterma,
Fam. Trachelina,
Fam. Colepina.
Fam. Halterina.

Order II. Suctoria, or Acinetina.

Not forming a
branched colony.

/A peduncle 1. Genna Podophrya.

No sheath... •< Tvr j i fFree 2. Genua Sphcerophrua.

\ ^o peduncle { ^-^^^ _ 3 ^^^^^ Trichopkria.

fSuckers simple ... J orancnea coiony. i jApeduncle 4. Genus ^a«./a.

ij-sneatn ••• -[jfo peduncle b. Gunm Solenophrya.

V Forming branched colonies 6. Genus Dendrosoma.

!,Sucker8 branched 7. Genus Dendrocotnefet.

Suckers on a long retractile tube 8. Genus Ophryodendron.

#ucker8 not on a ^
proboscis or tube."

INFUSORIA.

[ 422 ]

INJECTION.

Order III. Cilio-flagellata. Peridinina.

{The two portions of the cara- f Carapace with prolongations 1. Genns Ceratium.

pace equal in length I Carapace without appendages 2. Genua Peridinium.
r Borders of the notcli turned up and

The two portions unequal < lamelliform 3. Genns Dhiophysis.

^ -.,. , t Borders not turned up i. Genus Amphidinium.

JSo grooTe. Cilia on the anterior margin 5. Genus Prorocentrum.

Kent arranges the Infusoria thus : —

* Flagellata.

t Ingestion by all the surface.

Order 1. Trypanosomata. A rudimentary fla-

gellum, and an undulating membrane.
Order 2. Rhizoflagellata. A flagellum and lo-

bate pseudopodia.
Order 3. Padiuflagellafa. A flagellum and ra-
diate pseudopodia.
Order 4. Flaqellata Pamtomata. Flagella the
only motile organs,
ft Ingestive area anterior.

Order .5. Choano-Jlagellata. A flagelliim and a
collar,
ttt A di.stinct mouth.

Order 6. Flageltata Eusiomata. A flagellum

only.
Order 7. Cilio-Jlagellaia. A flagellum and cilia.

** CiLIATA.

Order 1. Holotricka. Cilia all over the body,

uniform.
Order 2. Heterotricha. Cilia general, but the

oral larger.
Order 3. Feri/richa. Cilia forming a spiral or

circular wreath.
Order 4. Sypotrocha. Cilia Tentral.

**» Tentaculifera (Acinetina.)
Order 1. Suctoria.
Order 2. Actinaria.

Kent defines 79 families, and 359 genera ;
of which our space will only allow a sketch
under the respective heads.

BiBL. Mliller, Animalc. infusoria, 1786 ;
Khr. Infusionsth. ; Dujardin, Infus. ; Pi-
neau, Ann. Sc. Nat. 3 ser. iii., v., ix. ; Stein,
Infus. ; Focke, Isis, 1836, and Physiolog.
Studien ; Meyen, MilUer^s Archiv, 1839 ;
Pritchard, Infusoria ; R. Jones, Ann. N. H.
1839, iii. ; Erdl, MiiUer's Archiv, 1841 ;
Griffith, An7i. N. H. 184-3, xii. ; Siebold,
Vergl. Anaf. ; Cohn, Sieh. n. Koll. Zeitschr.
iii. 260; Kolliker, Sith. u. Koll. Zeitschr. i.
198 ; Claparede and Lachmann, Etudes,
Geneve, 18G8 ; Engelmanu, Infus. 1862 ;
Jules Haime, Ann. Set. Nat. s. 3. t. xix.
109; Clark, Boston Mnn. N. H. 1866;
Balbiani, Se.vual Org. of Infus., Q. M. J.
1862, 176, 285 ; Ann. N. 11. 1858, i. 4,35 ;
Perty, Die kleinsten Lebensformen {neio
genera and species), 1852 ; Cienkowski, Qu.
Mic. Jn. V. 96 ; Lieberkiihn, Ann. N. II.
1856, xviii. 319; Carter, ibid, xviii. 115;
Gosse, Jn. Mic. S. 1857 ; Ray Lankester,
Qu. Mic. Jn. ; Diesinjr, Prothelm. 1865;
Engehnann, Gegenbaur''s Morph. Jahrb.
1876 ; Fromental, Microzoaires, 1876 ; All-

man, M. M. J. xiv. 171 ; Hackel, Jen.
Zeitschr. 1873, vii. 516 {rnorjjhol.) ; ibid. 561
{mw marine) ; Butschli, Arch. mikr. An.
1873, and Zeitschr. tciss. 2,qoI. 1878, xxx.
205; Simroth, Sch. Arch. 1876, xii. 51
{locom. appar.) ; Gruber, Zeitschr. wiss.
Zool. 1879, xxxiii. 439 {Jn. Mic. S. 1880,
282); Cartes, C'o77ip. rend. 1880, xc. 77
{glycoqenesis in) ; Dallinger, Jn. Micr. Soc.
1880, iii. ].

INFUSORIAL EARTH. — The fossil
deposits of Diatomacese were formerly so
called.

INJECTION.— The art of filling the
vessels and other minute tubular organs of
animals with coloured substances, by which
their relative size, arrangement, and relation
to the surrounding parts may be made ma-
nifest. The substances used for injections
consist of powders, mostly insoluble, mixed
with some liquid which holds them in sus-
pension or solution ; and while in this state
they are driven into the vessels by a syringe
or some similar contrivance. We shall first
give a sketch of the apparatus requisite, and
the method of making the liquids for in-
jecting the tissues of the Vertebrata, before
treating of the process itself.

Syringe. — Two or three syringes are requi-
site, of various sizes, adapted to the volume
of injection to be thrown into the vessels, or
the size of the animal or part to be injected.
In general, one holding 6 drms. or 1 oz.,
and another holding about 2 oz. will be
found the most useful. Each syringe must
be provided with two rings at the upper
part next the handle, so that it may be
firmly and easily held. The syringes when
in use should be surrounded by a roll or
two of flannel fastened with string, to pre-
vent their rapid cooling ; and the flannel
should be kept as dry as possible during the
process.

Sometimes a much smaller syringe, called
an oyster-syringe, is useful for injecting
very small and soft animals.

The plug of the piston is adapted to the
tube of the syringe by two pieces of wash-
leather, the method of replacing which must
be learnt at the time the s^Tinge is bought,

INJECTION.

[ 423 ]

INJECTION.

for it is difficult of description. Tlie plug
must work air-tight in the tube, which may
be proved by depressing the handle as far as
possible, then closing the nozzle of the sy-
ringe with one finger, withdrawing the
handle to its fullest extent, and letting it
go, when it should fly entirely home. If
this does not take place, the plug must be
re-leathered.

The handle of the syringe should be
graduated ; i. e. transverse lines should be
scratched upon it with the end of a file, or
in some other way, so that when its de-
scending movement is so slow as not to be
felt by the hand, it may be indicated to the
eye.

The syi'inges, and in fact all the mechani-
cal apparatus requisite for injection, may be
purchased of Mr. Neeves, Regent Square, or
of Mr. Ferguson, Smithfield.

The syringe must accurately fit the stop-
cocks and pipes.

Injectitig-pipes. — These must be of various
sizes, to suit those of the vessels into which
they are to be introduced; they are furnished
with two short transverse arms, by which
they may be tied to the vessel. The smallest
pipes which are made, easily become stopped
up unless thoroughly cleansed after use ; to
remove any obstruction.a very fine " broach"-
needle made of watch-spring is required,
and may be procured of Mr. Ferguson as
above.

Stopcocks. — One or two of these are use-
ful in stopping the injection from returning,
when the sjiinge is removed, or force ceases
to be applied to it.

Forceps. — One or two pairs of small tena-
culum forceps must be at hand ; these are
noticed in the Ixteoduction, p. xxv.

Jars or other vessels for holding the in-
jection. These may consist of confectioners'
jam-pots, or may be made of tin. The
former have the advantage of retaining the
heat for a considerable time. When in use,
the jars must be placed in a water-bath, or
in a tin vessel containing water, and placed
over a stove.

Stirring-rods. — These must be made of
wood.

Size. — The colouring-matters used for
the coarser injections are mostly insoluble
powders. These are usually mixed with
size or some form of solution of gelatine,
which holds them in suspension better than
water.

The size mostly used is Yoimg's patent
size, and it is sold in the shops. It should

be clear and fresh. Those who cannot
obtain this may prepare its equivalent by
dissolving 1 part of glue in 8 or 10 parts
of water with the aid of heat.

The principal liquid injections used may
be arranged according to their colours. In
regard to the proportions of the colouring-
matter to that of the size, it must be re-
marked that these vary as used by different
injectors; and that, in general, when the
vessels to be injected are very minute, and
the objects are to be viewed by transmitted
light, the size should be thinner, and the
proportion of pigment less, than under the
opposite conditions. When the injection
is directed to be strained, this must be done
through a piece of new flannel wrung out
of hot water, or through a "tammy sieve,"
which is more convenient. In preparing
the injections, great care must be taken
that the jars are perfectly clean, and that
no old injection remains adherent to them.
The colouring-matters, whether dry or dis-
solved, should be added to the size previ-
ously warmed in the water- bath, or the tin
vessel mentioned above ; and the whole
should be stirred until thoroughly incorpo-
rated. When trituration is spoken of, it
must be understood that the rubbing in a
mortar should be continued for a long time,
until the substance is reduced to the finest
possible state of powder.

Harting recommends pi'eparing a stronger
size than that mentioned above, containing
1 part of glue to 4 of water, and that the
chemical substances be dissolved in the
additional water requisite before being
added to the size, which would seem to be
preferable ; but we have found the method
recommended to answer every purpose, and
it has the advantage of greater simplicity.

Med Injection. — This is best made with
vermilion (bisulphuret of mercury), which
before use should be carefully examined as
to its purity from minute colourless crys-
talline particles, by viewing it by reflected
light, when they are easily detected. When
the vessels to be injected are very minute,
the vermilion is best previously levigated,
i. e. ti'itm'ated in a mortar with a small
quantity of water, the whole beino' after-
wards thrown into a large amount ot water,
and allowed to settle for a few seconds, so
that the coarser particles still left may sub-
side ; the upper portions of the liquid, con-
taining the tiner parts of the powder, are
then poured off and allowed to settle, the
supernatant water being again poured off,

INJECTION.

[ 424 ] '

INJECTION.

and either allowed to dry slowly, or mixed
while moist with the size.

The ordinary proportions for this injec-
tion are : —

Vermilion 1^ oz., Size 1 Ih., or
Vermilion 164 grs., Size 4 oz.

Stir the colouring-matter well with the
warmed size, then strai)i.

Other red colouring-matters have been
used, but they cannot be recommended.
Among them may be mentioned : — tbe basic
chromate of lead, prepared by boiling the
neutral chromate with caustic or carbonate
of potash ; the biniodide of mercury, formed
by decomposing bichloride of mercury with
iodide of potassium in atomic proportions ;
and the oxysulphuret of antimony.

Yellow Injection. — This is prepared with
the chromate of lead (chrome-yeUow), as
follows : —

Take of

Acetate of lead 880 grs.

Bichromate of potash 152 grs.

Size

8oz.

Dissolve the lead-salt in the warm size,
then add the finely powdered bichromate of
potash.

As thus prepared, some of the chromic
acid remains free, and is wasted, which may
be obviated by preparing the chromate of
lead with the chromate of potash in the
proportions of

Acetate of lead 190 grs.

Chromate of potash (neutral) 100 grs.
Size 4 oz.

or

Acetate of lead 196 grs.

Bichromate of potash 76 grs.

Carbonate of potash 41 grs.

Size 4 oz.

Thiersch iised chromate of potash and
nitrate of lead.

The chromate of lead prepared from the
bichromate of potash alone has the deepest
colour, and is that generally used.

White Injection. — The best white injec-
tion is made with carbonate of lead, thus :
take of

Acetate of lead 190 grs.

Carbonate of potash 83 grs.

Size 4 oz.

Dissolve the acetate of lead in the warm
size and filter ; dissolve the carbonate of

potash in the smallest possible quantity of
water, and mix it with the size.

143 grains of carbonate of soda may be
substituted for the above amount of carbo-
nate of potash.

A white injection (very inferior) may also
be made with carbonate of lime, by taking
of

Fused chloride of calcium . . Ill grs.

Carbonate of potash 167 grs.

Size 4 oz.

286 grs. of carbonate of soda may be substi-
tuted for the carbonate of potash.

Blue Injection. — In whatever manner
prepared, this cannot be in general recom-
mended ; for blue pigments reflect so little
light, that the injections made with them
appear almost black. The only one worthy
of mention is prussian blue suspended in
oxalic acid, which may be prepared with

Prussian blue 73 grs.

Oxalic acid 73 grs.

Size 4 oz.,

the oxalic acid being first finely triturated
in a mortar, the prussian blue and a little
water afterwards added, and the whole
then thoroughly mixed with the previously
warmed size.

General method.— V<\xe-a. the part for
injection has been selected, the first pro-
ceeding is to fix the pipe in some vessel; and
the larger this is, the more easily will the
pipe be inserted and fixed. When the vessel
has been isolated, if it has been cut across,
the pipe should be introduced at its end,
pushed up as far as possible, and a piece of
not too thin silk thread passed beneath and
tied around it, enclosing of covirse the nozzle
of the pipe ; the ends of the silk should then
be wound romid the arms of the pipe and
again tied, so that the pipe may remain
firmly fixed in the vessel. If the vessel be
not divided, a longitudinal slit should be
made in it for tlie introduction of the pipe,
the thread being passed round it by a
curved needle, the eye of which carries the
thread. As soon as the pipe has been fixed
in the vessel, all other vessels commimi-
cating with it should be tied round with
silk thread or closed in some other way, that
the injection may not escape : sometimes it
is requisite to enclose a part of the tissue
itself in the ligature ; in other instances
their closure may be effected by fusion of
the tissue at the spot from which the injec-
tion might, escape, by the application of a
red-hot iron.

INJECTION.

[ 425 ]

INJECTION.

The organ or part to be injected is then
immersed in warm water, iu order that it
may become heated throughout ; and if it
be large aud of considerable thickness, this
may take some time ; and fresh warm water
must be added at intervals to keep it at the
same temperature, which should be about
as great as can be borne by the hand. If
the water be too hot, the vessels and tissues
will be rendered brittle, and the whole will
be spoiled. Moreover the part shoidd not
be kept longer in the water than is absolutely
requisite, fur the same reason. While the
tissue is becoming heated in the water, the
injection should be prepared, or be heated
if previously prepared, and kept constantly
stirred ; the stopcocks should also be im-
mersed iu hot water.

As soon as all is ready, the stopcock
turned open, is fixed to the syringe, aud
some hot water is drawn into and expelled
from the syringe two or three times, so that
it may become properly heated. It is next
filled with the injection, taking special care
that no air be allowed to enter, to avoid
which it must be filled, emptied, and refilled
several times, the nozzle being kept beneath
the surface of the injection. The syringe is
then taken iu the hand, a little of the injec-
tion being forced out at the nozzle of the
stopcock, which is next loosely inserted
into the pipe ; and some of the injection
being urged into it by depressing the handle,
the pipe is filled, and the nozzle introduced
into it. Very gentle pressure is then made
upon the piston, so that the injection may
be driven into the vessels ; and this must be
continued until the piston ceases to be felt
to move, or is seen not to enter the syringe
further, by watching the graduations on its
handle. When this is found to be the case,
firmer pressure must be made and the effect
noticed. But practice can alone guide as to
the time at which the pressure should cease,
or when as much injection has been forced
into the preparation as is required. Some
judgment may be made from the colour
assumed by the preparation ; or, the stop-
cock being turned oft, and the syringe sepa-
rated from it, the preparation may be exa-
mined with a low power, while laid upon a
large glass plate.

During the continuance of the process,
the preparation, the injection, and the pipes
must be kept at the original temperature ;
and should any part be found to become
cool, the stopcock must be turned off, the
syringe separated, the injection retui-ned to

the jar, fi*esh warm water added to the
preparation, and the whole process recom-
menced as at first.

If, during the process, there should be an
escape of the injection from any part, this
need not cause alarm if slight ; should it,
however, be considerable, it must be stopped
by one of the means pointed out above —
perhaps by the orifice of the vessel and sm*-
ronnding parts being grasped by the tena-
culum-forceps, and the whole included in a
ligature. If the preparation be small, not-
withstanding a considerable escape of the
liquid, a very good injection may often be
made.

As soon as the injection is completed, a
ligature should be placed around the vessel
into which the pipe is inserted, beyond its
nozzle ; the pipe is next removed, and the
preparation should be immersed iu clean
cold water, and kept in it for an hour or
two at least. It may then be withdrawn
and sections made of it with a knife, razor,
or some other instrument.

Large pieces of injected preparations are
best preserved in a stoppered bottle con-
taining dilute spirit of wine (1 spirit to 2
water, or equal parts). See also Preser-
vation.

When two or more sets of vessels are to
be injected, the process should be continued
uninterruptedly until completed; i. e. as soon
as the injection of one set has been com-
pleted, auother pipe should be at once in-
serted into one of the other set, and so on.
Or what is better, if possible, the pipes for
the two or three sets should be introduced
and fixed at once, before the process is com-
menced.

As regards the period after death at which
the injection should be commenced, this
varies with the kind of organ or tissue : if it
be delicate, the sooner the better ; whilst if
the vessels be comparatively large, by some
little delay the tissue becomes somewhat
softer and more yielding.

When a tissue has been successfully in-
jected, the vessels appear plump aud well
filled by reflected light. But if they are not
so, the preparation has its value; for it will
perhaps well display the relative positions
of the capillaries to -the surrounding tissues
when viewed by transmitted light — often
even better than when the injection has
been what is termed successful. In fact,
when the vessels are well filled, little more
can be seen iu general than the relative
situation of the vessels to each other.

INJECTION.

[ 426 ]

INJECTION.

The choice of the kind of injection is not
a matter of much importance, except as
regards the facility with which the vessels
are filled. The arteries are in general filled
with red injection, the veins with yellow,
and the ducts (as the urinary tubules) with
white. The chromate of lead is perhaps
the finest injection and runs best, except
that made with prussian blue and oxalic
acid, which does not reflect enough light
where the vessels are to be viewed by re-
flected light, although when these are very
minute and can be conveniently viewed by
transmitted light it may be preferred.

It may be remarked that, if it be required
to use a yellow (the chromate) injection
and a white (the carbonate of lead) for
two sets of vessels in one preparation, the
chromic acid in the former must previously
be completely neutralized ; otherwise it will
render the white (carbonate of lead) yellow.
This may, however, be avoided by substi-
tuting the carbonate of lime for that of lead.

As microscopic objects, nothing can ex-
ceed the beauty of injected preparations;
and to be seen in theii' greatest perfection
they should be dried, moistened with oil of
turpentine, and mounted in Canada balsam.
At the same time it must not be forgotten
that, when dried and preserved in this man-
ner, the real arrangement of the vessels is
more or less distorted, those lying in dif-
ferent planes being brought into the same,
and so on.

In Plate 39. figs. 3.3, 34, and 35, we have
given representations of three injections
viewed by reflected light, — tig. 33 being
taken from the liver of a cat, in which in-
jection made with vermilion was thrown
into the portal vein, and that with chromate
of lead into the hepatic vein ; tig. 34 is a
portion of the lung of a toad injected with
vermilion ; and tig. 35 is a portion of the
kidney of a pig, the arteries and Malpighian
tufts (Kidney) being tilled with the red
(vermilion) injection, and the urinary tu-
bules with the white (carbonate of lead).

Self-injection occupies an important posi-
tion amongst the various modes. The vas-
cular system of the frog may be injected by
inserting a pointed glass tube tilled with
the coloured injecting fluid into the vena
cava. The fluid passes into the heart, and
is distributed through the system by the
force of the heart itself. The biliary vessels
of living animals have been injected by
means of colouring-matter introduced into
the jugular veins. i

Toldt has injected the lymphatics on this
system ; and he introduces a granular pig-
ment (aniline) precipitated by water from its
alcoholic solution into the blood.

The perfect injection of an organ or an
entire animal of considerable size is a
tedious and fatiguing process. We have
therefore contrived a very simple piece of
apparatus, which any one can prepare for
himself, and which 'effects the object by
mechanical means. It consists of a rect-
angular piece of board, 2' long and 10" wide,
to one end of which is fastened an inclined

Fig. 360.

piece of wood suppoii;ed by two props, as
shown in fig. 360. The inclined portion is
pierced with three holes, one placed above
the other, into either of which the syringe
may be placed — the uppermost being used
for the larger, the lowermost for the smaller
syringe ; and these holes are of such size as
freely to admit the syringe covered with
flannel, but not- to allow the rings to pass
through them. The lower part of the
syringe is supported upon a semiannular
piece of wood, fastened to the upper end of
an upright rod, which slides in a hollow
cylinder fixed at its base to a small rect-
angular piece of wood ; and by means of a
horizontal wooden screw, the rod may be
made to support the syringe at any height
required. The handle of the syringe is let
into a groove in a stout wooden rod con-
nected by means of two catgut strings with
a smaller rod, to the middle of which is
fastened a string plajdng over a pulley, and
at the end of which is a hook for supporting
Aveights, the catgut strings passing tlirough
longitudinal slits in the inclined piece of
wood.

In use, the part to be injected is placed
in a dish of some kind containing warm
water, supported at a suitable height beneath
the end of the syringe by blocks of wood.
The syringe is then tilled with injection,
passed through the proper aperture in the

INJECTION.

C 427 ]

INJECTION.

inclined board, and fitted to the pipe, the
stopcock being turned off. The rod and
strings are next adjusted, and, a suitable
weight being added, the stopcock is very
slowly turned on, and the effect watched.
If the handle of the syringe does not move,
more weight must be added, the stopcock
always being turned oft' when this is about
to be done.

A great advantage of this apparatus is,
that it sets at liberty the hands, so that an
escape of injection may be arrested, or fresh
warm water added, without interruption of
the process.

Other automatic methods have been pro-
posed, as that of Kutherford, which is
this : —

A large jar of water is attached to a
pulley, so that it can be elevated to any
height. A long elastic tube with a stopcock
is connected with the interior of the iar,
near its bottom, so that the water may flow
out when required. The other end of this
tube transmits the water into a large
Woulfe's bottle having three apertures.
The water flows in by one aperture, through
a glass tube which passes to the bottom
of the bottle. The air is thereby forced
through the other two apertures, one com-
municating with a mercm-ial manometer for
indicating the pressure, the other transmit-
ting the air through an elastic tube to a
second Woulfe's bottle containing the injec-
tion. This bottle has two apertures. The
air is forced upon the surface of the liquid,
and a glass tube, reaching nearly to the
bottom of the bottle, transmits the injection
to an elastic tube joined to a glass or metal
nozzle placed in the vessel. Any number
of Woulfe's bottles may be added, so that
different injections can be thrown in at the
same time. The pressure can be regulated
with the greatest nicety.

When it is not required to fill the capilla-
ries, but only the smaller arteries or veins,
the colouring-matters need not be prepared
by double decomposition, and the following
substances may be used : —

Red. — Size 1 lb., vermilion 2 oz.
Yellow. — Size 1 lb., King's yellow

(orpiment) or chrome-yellow 2^ oz.
TTMc— Size 1 lb., flake-white 3^ oz.
jilue. — Size 1 lb., fine blue smalt 6 oz.
Black. — Size 1 lb., lamp-black 1 oz.

Injections made with transparent solu-
tions are now largely used, the objects being
viewed with high powers, by transmitted

light. Fine gelatine is usually employed,
and is dissolved in water over a water-bath,
the colouring-matter already in solution
being then added, and the mass introduced
into a Woulfe's bottle, which must be im-
mersed in a warm water-bath. The injec-
tion takes long to do; and the warmth must
be kept up. The colouring matters usually
employed are prussian blue and carmine —
the latter not in a state of complete solu-
tion, but partly precipitated by the addition
of a little weak acid from its alkaline solu-
tion. Thiersch, whose transparent injec-
tions are wonderful, uses a transparent yel-
low, and gi'een, — the former from chromate
of potash and nitrate of lead, and the latter
from a mixture of this with blue. Beale,
in order to avoid the injecting of warm
fluids, uses colouring-matter, water, glyce-
rine, and traces of hydrochloric acid ; after-
wards the injected mass is placed in absolute
alcohol.

Carter's carmine injection is made thus :
— dissolve 60 grains of pure carmine in 120
grains of Liq. Ammon. fort., and filter if
necessary; mix with this 1^ oz. of hot
solution of gelatine (1 to 6 of water) ; mix
another h, oz. of the gelatine solution with
86 minims of glacial acetic acid, and drop
this little by little into the solution of car-
mine, stirring briskly the whole time. Dry,
or harden in solution of chromic acid ; cut
with a sharp razor, and mount in Canada
balsam.

Beale's fine blue injection is made with

Glycerine 1 oz.

Spirit of Wine 1 oz.

Eerrocyanide of potassium .... 12 gr.

Tinct. or sol. of perchlor. iron . . 1 dr.

Water 4 oz.

Dissolve the ferrocyanide in 1 oz. of the
water and the glycerine, and the iron in
another oz. Mix gradually, adding the iron
to the ferrocyanide. Then add the spirit
and the rest of the water.

For very fine injections, the mixture may
be diluted with 3 oz. of glycerine, and half
the quantity of ferrocyanide and iron used.

The ferridcyanide of potassium is often
used, forming Turnbull's blue, which is
brighter and less liable to fade. This is
made with ferridcyanide of potassium
10 grs., sulphate of iron 5 grs., glycerine
2 oz., water 1 oz., and alcohol 1 drachm.

Numerous other fine injections are de-
scribed by Beale and Frey,

INJECTION.

[ 428 ]

INOMERIA.

The tissues of the Invertebrata are so
soft, that the ordiuary syringes and pipes
can rarely be used for injectiug them, and
recourse must be had to a finer and lighter
form of apparatus. This may consist of a
fine trochar, with a needle. In using it,
the small vessel through which the injection
is to be thrown, is held with forceps against
the end of the trochar, and punctured with
the needle. The trochar is next directed
into the puncture, and the needle withdrawn.
The small nozzle of a syringe is then intro-
duced into the ujjper end of the trochar,
and the injection thrown in. A form pro-
posed by Harting consists of a common
glass pipette of moderate width, and of a
caoutchouc tube the smaller end of which is
fastened by means of thread to the broader
end of a tine, curved, glass nozzle. In using
this apparatus, the pipette is first filled with
the injection, and its lower portion intro-
duced into the broader end of the caout-
chouc tube, which, from its conical form, it
accurately closes.

Different liquids for injection are also
usually requisite ; and many have been i-e-
commended. Among these may be men-
tioned:— I, indigo, triturated with oil and
diluted with oil of turpentine ; 2, oil-paints
diluted with oil of turpentine ; 3, infusion
of logwood {HcBmatoAijloii) ; 4, solution of
carmine in size or in ammonia ; and 5, solu-
tion of alkanet in turpentine.

A considerable escape of the injection is
often unavoidable in these cases, and must
therefore not be heeded.

Some injectors simply introduce the in-
jection into the dorsal vessel or lacunae,
whence it is propelled to all parts of the
body by the circulation. Thus Agassiz
says that if the indigo injection (1) be in-
troduced in this way into insects, it is seen
to circulate almost instantaneously in every
part of the body, and on subsequently open-
ing the insect all parts of the body are
found to be coloured. We believe that
Blanchard also adopts this method. Pro-
bably the best injections for this purpose
■would consist of alkanet and turpentine.

Injections may be preserved either in the
dry or wet state. For the former, sections
should be made, thoroughly dried upon
slides, then moistened with oil of tur-
pentine, and mounted in balsam. For pre-
servation in the wet state they must be
mounted in cells while immersed in dilute
spirit, Goadby's B. solution, or in chloride
of zinc (see Pbesebvation).

We have not space to give a list of
injected preparations; they are all very
beautiful, but we can only notice a few of
the most interesting. For practice in the
art of injecting, we may recommend the
kidney of a sheep or pig, — one system of
vessels being alone filled with red or yellow
injection ; and this should be the arterial.
Afterwards, in another kidney, the urinary
tvibules may be injected first, with white
injection, and sub^-;equently the arteries with
red or yellow. A portion of the small
intestiue, exhibiting the general capillaries,
with the plexuses of the villi, forms a
beautiful object as prepared from the rabbit,
the rat, &c. Among other preparations
may be mentioned : — the liver of various
animals, as the cat, the rabbit, &c. ; the
lungs of the cat, rabbit, &c., in which the
capillaries are very minute ; those also of
reptiles, as the frog, triton, boa, and other
snakes, in which they are coarser, but very
beautifully arranged ; the lungs of birds ;
the kidneys of the frog and triton ; the web
of the frog's foot ; the cOiary processes and
choroid coat of the eye ; the gills of the eel
and other fishes ; the lungs of kittens, kc.
which have not breathed, the air-cells being
injected from the trachea ; the skin of the
frog, and especially of the triton, cfcc.

BiBL. Tulk and Henfrey, A7i. Mnnip. ;
Robin, Microscope \ Quekett, on Inject;
Goadbv, in Wvthes's * Microscopist;' Beale,
Hotv ^-c; Rutherford, Hist. 1876; Mose-
ley, Q. Mic. Jw. 1871, 389, Inject. Insects)
ri-ev, Mikr. 1881.

INODER'MA, Kiitz.— A genus of Pal-
mellacese (Confervoid Algae).

Char. Cells oblong, usually in longi-
tudinal rows, loosely vmited by a soft jelly ;
thallus gelatinous, membranous, irregularly
expanded.

/. lanieUosum. On submersed wood and
stones, everywhere.

BiBL. Rabenhorst, Fl. Alg. iii. p. 37.

INOME'RIA, Kiitz.— A genus of Oscil-
latoriaceae (Confervoid Algfe) -u-ith calca-
reously hardened incrusting fronds, growing
on stones in fresh water. Fronds compused
of vertical, parallel, whip-shaped filaments,
with the sheaths obscure, connected to-
gether, and decomposed into very slender
fibrils above. Kutzing supposes his /. Roe-
moriana to be synonvTuous with Hassall's
Lithonevia crusldceiim.

BiBL. Kiitz. Sp. Alg. 343, Ic. Phys. ii. pi.
83 ; Hassall, Alcf(Z, 26(3, pi. 65. fig. 3 ; Ra-
benhorst, Fl. Alg. ii. 223.

INOSITE.

[ 429 ]

INSECTS.

I'NOSITE. — Or muscle-sugar, is a colour-
less crystalline substance, occurring- in tlie
muscular tissue of the heart, in tlie liver,
the lun^'-, kidneys, and brain ; and in plants,
in grape-juice, wine, and haricot-beans.
The crystals form rhombohedra, and are
soluble in water, but not in alcohol or ether.
INSECTS. — A class of invertebrate arti-
culate animals.

Char. Head distinct, furnished with two
antennjE ; three pairs of legs ; respiratory
organs consisting of trachetB ; cutaneous
skeleton composed of chitine.

Insects are distinguished from the Arach-
nida by the head being distinct from the
thorax, and the presence of antennae ; and
from the Crustacea by the respiratory organs
consisting of trachese.

The body consists usually of thirteen seg-
ments or somites — one for the head, three
for the thorax, and nine for the abdomen,
the legs being attached to the second, third,
and fourth segments.

The cutaneous skeleton or integument of
insects probably consists of three layers — an
outer epidermic, an intermediate pigment,
and an internal fibrous layer ; but consisting
as it does of chitine, it is very imperfectly
resolvable into its elementary components.
The epidermic layer often presents a distinct
cellular aspect (PI. 35. fig. 30 a), sometimes
the cells appearing as if flattened and over-
lapping (PL 35. fig. 30 c) and their free
margins fringed with minute hairs (fig. 30 6).
In other instances the epidermis appears
uniform and structureless. In its deeper
portion the epidermis is often strongly co-
loured by a resinous pigment, which is
removable by prolonged maceration in so-
lution of potash or in oil of turpentine. Be-
neath these imperfectly separable layers, is
another representing probably the cutis, and
consisting mostly of numerous secondary
layers made up of fibres, running ^^arallel or
interlacing, and leaving fissures and tubes
between them, sometimes presenting a stel-
late appeai'ance : these fibres may be sepa-
rated by maceration in caustic potash.

The outer surface of the integument of
insects is usually furnished with processes
of various kinds, as tubercles, hairs, spines,
scales, &c. (.see Haies and Scales). The
inner surface also gives oft" processes, which
form a kind of internal skeleton, serving for
the attachment of muscles, &c. In sketch-
ing the various parts of which the skeleton
is composed, it must be understood that
they are not always equally distinct, and

that upon their degree of development, form,
and general structure the characters of the
families, genera, and species are mainly
founded.

The head (fig. 361 a) consists of an upper
anterior portion (PI. 33. fig. 1 d), the clypeus,
and an upper posterior portion (fig. 1 b), the
epicranium or vertex, which are sometimes
separated by a suture ; a posterior portion
or occiput (fig. 2 + ), by which the head is
articulated with the prothorax ; and a pos-
terior inferior portion (fig. 3 n), the gula.

The eyes are situated upon the upper, an-
terior, or lateral parts of the head, and are
of two kinds, simple and compound. The
simple, called ocelli or stemmata (PI. 35. fig.
2 «; PI. 33. fig. 24 h), are usually from one
to three in number, but sometimes are
numerous in larvae ; they appear like shining
smooth specks (PI. 33. fig. 4), and usually
form a triangle behind or between the com-
pound eyes. They consist of an arched,
round, or elliptical cornea, behind which is
a conical or cylindrical lens, which is sur-
rounded by a layer of pigment of various
colours, resembling a choroid membrane,
and is in connexion with a filament of the
optic nerve.

The two compound eyes (fig. 361 h) are
large, usually round or kidney - shaped
(PI. 33. figs. 1 c, 3 c), situated upon the
upper and outer part of the head, and are
sometimes so large (as in the Diptera, Li-
bellula, &c.) as almost or quite to touch
each other in front. They may be regarded
as composed of numerous simple eyes closely
aggregated ; their cornese vary in thickness,
are but slightly arched, quadrangular or
hexagonal in form, and in immediate con-
tact laterally. Hence the compound cor-
nea, when viewed from before or behind,
presents the appearance of a membrane with
numerous beautifuUv regular six- or four-
sided facets (PI. 33. figs. 5 a, b). The facets
are very variable in number ; but often many
thousands are present. They are occasion-
ally broader in fiont than behind, and are
sometimes doubly conve.x (as in the Lepi-
doptera), at others concavo-convex (in Li-
belhda, PI. 33. fig. 6 c); but usually the sur-
faces are parallel. The cornea possesses a
laminated structure. -

Behind each cornea is a transparent cone
(PI. 33. fig. 6 *), representing a crystalline
lens, the apex of which is imbedded in a
transparent rod or pyramid lauiiuated in
structure, corresponding to a vitreous hu-
mour ; and this is probably continuous with

INSECTS.

[ 430 ]

INSECTS.

n branch of the optic nerve. The length of
the lens is variable, in the Diptera being
very short, whilst in the Coleoptera and
Lepidoptera it is five or six times as long

as broad, and in Libellula it even exceeds
this length. The compound cone, consist-
ing of the lens and vitreous humour, is sur-
rounded by a sheath of pigment, forming a

Fig. 361.

9\

Diagram showing the principal parts of the cutaneous skeleton of a grasshopper.

a the head, with the eyes b and the antennae c; d, the thorax, consisting of e the prothorai, to which the first pair
of legsyare attached; g, the mesothorai, to which the first pair of wings h, and the second pair of legs t are attached ;
k, the metathorai, to which the second pair of wings U and the third pair of legs m are attached; n, abdomen ; m,
femur ; o, tibia with its spines, and p tarsus with its claws.

choroid membrane (PI. 33. fig. 6r), in which
numerous tracheae ramity ; this extends over
the front of the base of the cone, leaving,
however, a small pupillary space or pupil,
which is separated from the back of the
cornea by au anterior chamber.

The atitennce are noticed under Antenna.

The trophi or organs of the mouth vary
in structure in the different orders, but the
following form the typical parts : an upper
central single piece, the labrum, or upper
lip (PI. 33. figs. \e,^e, 22 a), forming the
upper biiuudary of the mouth, and articu-
lated at its base with the clypeua. A lower
single piece, forming its lower margin, called
the labium or lower lip (PI. 33. fig. 2 /, /, ??»).
This consists of several parts : the most
posterior is the mentum (fig. 3 /), which is
articulated posteriorly with the gula (fig.3?j).
Sometimes an intermediate portion occurs

the submentum (fig. 3 m) ; at others this is
consolidated with the occiput ( fig.2»!). The
most anterior portion is the ligula (figs. 2,
3 i), which is frequently notched or lobed,
and is sometimes furnished with two lateral
portions called paraglossae (fig. 2*). Between
the ligula and the mentum or submentum
are the palpigers, one on each side (fig. 2 i) ;
these are sometimes united, and to them
the labial palpi (figs. 2, 3 k) are attached.
Below the labrum are the mandibles, one on
each side, forming two strong curved jaws,
and frequently furnished with powerful
teeth (figs. 3/, 22 b); these are the proper
organs of manducation. Below the mandi-
bles are two other lateral organs, the maxilhe
(figs. 1, 2, 3^; fig. 22 c).; they are usually
less firm than the mandibles, and serve to
hold and convey the food to the back of the
mouth. Each maxilla is furnished with a

INSECTS.

[ 431 ]

INSECTS.

jointed palp (figs. 1, 2, 3 /*), and sometimes
with an appendage called the galea or
helmet (fig. 22 *), and an inner cm-ved and
acute portion termed the lacinia or blade
(fig. 22 1). In some insects there is a di-
stinct soft and projecting organ, forming the
floor of the moutli, the lingua or proper
tongue (fig. 22 d) ; the tongue of the cricket
(fig. 23) is a favourite and beautiful micro-
scopic object.

These structures are best examined in the
Coleoptera or Orthoptera, in which most of
these parts are distinct. In the other orders
they are altered in structure to adapt them
to the nature of their food.

Thus in the Lepidoptera, the labrum and
mandibles are reduced to three minute tri-
angular plates ; the maxillcTS are elongated
to form the antlia (Antlia), at the base of
which a pair of minute palpi are often to be
detected. The labium is small, triangular,
and furnished with a pair of large palpi
clothed with long hairs or scales, and serving
for the defence of the antlia.

In the Hemiptera (PI. 33. figs. 26, 27),
the labrum is short and pointed, and over-
laps the root of the rostrum ; the mandibles
and maxillce are transformed into slender
lancet-like organs (the maxillary palpi being
obsolete), enclosed within the equally elon-
gated horny and jointed rostrum or labium,
the labial palpi also being obsolete.

In the Diptera (PI. 33. figs. 29, 30), the
five upper organs, together with the internal
tongue, are elongated into lancet-like organs,
the maxillary palpi being attached to the
base of the maxillte. These six organs are
enclosed in a fleshy thickened piece, the
labium, often terminated by two large lobes
which act as suckers. In many species,
however, some of these lancet-like organs
are obsolete. This kind of mouth is termed
a proboscis.

These varieties are further noticed under
the heads of the genera selected for illustra-
tion.

Behind the head is the thorax. This
consists of three rings or pieces, each of
which supports a pair of legs (fig. 361 e, g,
k). The first ring is called the prothorax
(e), the second the mesothorax (g), and the
third the metathorax (k). Each of these
rings consists of a dorsal and a sternal piece ;
the dorsal half-rings are called the pro-
notum, mesonotum, and metanotum ; the
ventral or sternal the prosternum, meso-
sternum, and metasteraum. In the four-
winged insects, the anterior wings are

attached to the central piece or mesothorax
(//), the posterior wings to the metathorax
{k). In the Diptera, the wings are attached
to the mesothorax, and the halteres to the
metathorax. Various other subdivisions
have been made of these parts, but they are
too numerous to mention here. It may be
remarked, however, that the epimera are the
pieces to which the basal joints of the legs
are directly attached ; that the under part of
the thorax or pectus is sometimes furnished
with an elongated acuminate appendage, the
sternum ; and that the scutellum or shield
is a piece existing at the upper and back
part of the mesonotum, and extending be-
tween the wings.

The kffs (usually called feet) are placed
on the underside of the body, and are joined
to its segments at an articular cavity exist-
ing between the sternum and the epimeron,
called the acetabulum. Each leg usually
consists of five parts. The fu'st is the hip
or coxa (PI. 35. fig. 9 r/) ; but sometimes
there is a small very moveable piece between
the epimeron and the coxa (PI. 3o. fig. 9,
between / and g), called the trochantin ;
this, however, is generally absent or con-
solidated with the coxa. The second joint
is the trochanter (PI. 35. fig. 9 k) ; it is
mostlv small, and annular. The third is the
thigh''or femur (fig. 361 m ; PI. 34. figs. 4,
5, 7 d), the thickest and usually the largest
joint of the leg. Next comes the fourth, the
tibia (fig. 361 o ; PI. 34. figs. 4, 5, 6, 7 c),
which is thinner, usually compressed, and
frequently furnished with spines, spurs, or
other appendages, especially at its end ; in
the ant the tibiae have each a beautiful
pectinate process. The last portion is the
foot or tarsus (fig. 361 p ; PI. 34. figs. 6,7 a),
which consists of several joints arranged in
a row. The number of these joints varies in
different insects ; sometimes it is different
in the anterior and posterior pairs of legs ;
they are, however, most commonlv five.
The last joint of the tarsus is usually fur-
nished with appendages, in the form of
hooks or claws, mostly two, and frequently
serrated, especially near the base. Some-
times also it has two or three delicate mem-
branous or fleshy cushions, called pulvilli
(PI. 34. figs. 7 & 8). ; these are more or less
covered with hairs, which are sometimes
terminated by little disks (fig. 9), and by
which it is supposed that the insects are
enabled to ascend or adhere to polished
surfaces in opposition to gravity. In other
insects elegant brush-like appendages are

INSECTS.

[ 432 ]

INSECTS.

met witli in the same situation. Disks of j
the same kind but larger, and peculiarly- i
arranged hairs, sometimes occur upon the I
upper joints of the tarsus (PI. 34. fig. 6, Dy-
Tiscus ; and tig. 4 a, Apis).

The structure of the legs of insects in the
larval state (PI. 34. figs. 32, 33) ditfers con-
siderably from that of the imago as de-
scribed above.

The iciiH/s are dry, membranous, and
transparent organs, consisting of two layers,
which are couiiuent at the margins, and are
folds of the integument. Between them
nm canals, commonly called veins, nerves,
or nervures, which are more or less numerous
and ramified ; and upon their arrangement
the distinguishing characters of the genera
&c. are sometimes founded (Wings). The
veins are formed by two wide horny half-
canals in the upper and under plates, of
which the wings consist. The main veins
arise from the point of attachment of the
wings to the thorax, and gradually diminisli
in diameter vmtil they reach the extremity
of the wings. The veins convey the circula-
ting liquid, and contain each a tracheal
branch, which communicates with the
trachete of the thorax. Each nervure con-
tains a trachea ; and the blood circulates
around it. In iiight they are said to be
distended and the wings kept expanded, by
air from the interior of the body. In some
kinds of wings the circulating currents are
not confined to narrow channels as in the
veins, but traverse a large part of the
breadth of the wings (Coccinella).

Most insects have four wings ; but in
some the males only are furnished with these
appendages. In the Diptera,the posterior pair
of wings are rudimentary, being replaced
by two little club-shaped bodies, called the
halteres, poisers, or balancers. In this order
also, and in some insects belonging to other
orders, a pair of small and rounded membra-
nous or scaly appendages are attached to
the back of the base of the first pair of
wings, called in the former the squamae
halterum, and in others, alulae or winglets.
In some insects, as in the beetles (Coleo-

!)tera), the anterior pair of wings are hard,
lorny, and opaque, forming wing-covers or
Elytra (tig. 302), from the presence of a
horny layer ; and the lower wings, which
are usually larger, are folded together
beneath them, when at rest. In others, the
posterior wings disappear, and the elytra
coalesce at their inner margins. Sometimes
the anterior wings are horny or leathery at

the base, and membranous towards the
summit (tig. 363) ; these are called hem-
elytra. At others, all the wings are thin,
membranous, and transparent, as in the
Hymenoptera and Neiiroptcru.

In the Lepidoptera, they are covered with
beautiful feathers or Scales.

There are also other modifications of the
wings of certain insects, adapting them for
special functions. In the Orthoptera the.se
modifications are the agents producing the
well-knowm chirping sounds, as in the male
cricket and grasshopper. In the common
house-cricket, Acheta domestica, each of the
upper wings or elytra exhibits a clear space
near the centre (PI. 34. fig. 10 a), traversed
by a single vein only, or at least by a very
few veins. This space has received the name
of the drum or tympanum . Bounding it ex-
ternally is a large dark longitudinal vein,
provided with three or four elevated longi-
tudinal ridges. Immediately in front (. f the
tympanum, near the base of the elytra, is a
transverse horny ridge, tapering outwards
and furnished with numerous short trans-
verse ridges or teeth, and forming a kind of
file or bow (PI. 34. fig. 10 b). When the
two elytra are rubbed across each other, the
bow being drawn across the ridges gives
rise to the peculiar sound, the intensity of
which is increased by the tympanum acting
as a sounding-board. The apparatus of the
grasshopper is essentially of the same struc-
ture. It must be stated, however, that va-
rious other explanations of the origin of the
stridulating noise produced by these insects
have been given. Thus by some authors the
two bows are stated to work across each
other, whilst by others the legs are supposed
to act against the bow. This subject pos-
sesses interest for future observation.

In other insects, there is a peculiar mecha-
nism for uniting the anterior and posterior
wings of each side, so that they may be kept
steady and may act in unison during tiight.
In the I^epidoptera, the moths only are pro-
vided with a minute hook arising from the
base of the costal nerve of the lower wing,
and inserted into a socket near the base of
the main nerve, on the underside of the
upper wing. In the Hymenoptera, there are
many such hooks arranged along p.irt of the
costal nerve at the anterior and upper
margin of the second pair of wings (PI. 34.
tig. 13). When the wings are expanded,
these attach themselves to a little fold on
the posterior margin of the anterior wing
(tig, li n), along which they play freely

IXSECTS.

[ 433 ]

INSECTS.

■^lien the wings are in motion, sliding to and
ti'o like the rings on the rod of a window-
Curtain. These hooks are somewhat twisted
towards their free end, recurved and some-
times notched at the point. They vary in
number in different genera and even in
the sexes. In the Hemiptera the Avhole
margin of part of the anterior wing is hooked
over a corresponding recurved part of the
posterior, so as to produce the same effect.

The halteres of the Diptera and the elytra
of beetles present in certain parts a multi-
tude of vesicular projections of the external
membrane ; and a nervous lilament passes
to each. Hicks considers them to be organs
of smelling.

The abdomen (fig. .361 w) forms the third
and terminal portion of the body of insects.
It usually consists of nine or ten rings or
joints, tlie posterior of which, however, are
sometimes so concealed, so small or so fused
with the others, that they appear to be
absent. The last segment of the abdomen
of many insects in the females, is furnished
with five or six valves or setse, some of
which form stings, saws, or borers,
according to the function they perform as
weapons of defence, or to cut through the
tissues of plants or animals, so that the eggs
may be deposited in them. The saws are
well-known interesting objects. See Chal-
ciDiD^, Cynipid^, and Stings. The ab-
domen contains the principal part of the
alimentary canal and its appendages, with
the organs of reproduction.

The alimentary canal varies in length in
different insects, and even in the same insect
at various periods of its development. It
consists of the following parts : — 1 . The oeso-
phagus (PI. 3.5. fig. 2 6), a muscular organ
extending through the thorax ; it is some-
times dilated to form a crop or iugluvies, as
in the Lepidoptera, Hymenoptera, and Di-
ptera ; and this occasionally forms a lateral
sac, connected with the oesophagus by a
narrower portion only, and called a sucking
stomach. 2. Next follows the muscular
stomach, proventriculus or gizzard (fig. 2 c),
which is distinguished by the frequently
great development of its lining membrane
into plates, teeth, or hooks of horny tissue
(PL 34. fig. 1) ; these serve to triturate the
food, and have long been known as beautiful
microscopic objects. .3. This is succeeded by
a long cylindrical true stomach or ventri-
culus (d), in which digestion takes place.
4. Behind this is a longer or shorter small
intestine (PI. 35. fig. 2, between d and /),

terminating in 5, a dilated portion, forming
a large intestine or colon; behind which is
a short rectum. The structure and length
of the parts of the alimentary canal vary
generally according to the nature of the
food, although this is not always the casein
regard to the latter.

The alimentary canal is covered by an
outer homogeueousperitoneal layer ; beneath
which is a muscular coat, consisting of lon-
gitudinal and transverse fibres. Internally
it is lined by a homogeneous epithelial layer,
consisting, in part at least, of chitine. Be-
tween the latter and the muscular coat, at
the middle of the alimentary canal, is a layer
of cells, which probably perform a glandular
function. The large intestine or colon of most
insects in the imago state contains from
four to six peculiar organs of doubtful
nature, arranged in pairs, either transversely
or longitudinally. These consist of trans-
parent rounded, oval, or elongated tubercles,
projecting inside the colon, sometimes with
a horny ring at the base, and traversed by
tufts of tracheoe. These organs are most
numerous iu the Lepidoptera. They are
never found in insects in the larva- or pupa-
state.

In most insects, salivary glands are present
as one, two, or rarely three pairs of colour-
less sacs or tubes of very variable form and
length, sometimes scarcely extending beyond
the prothorax, at others accompanying the
alimentary canal into the abdomen. They
consist of an outer homogeneous envelope,
lined with colourless nucleated cells, and
frequently have one or more distinct ducts,
sometimes containing a spiral fibre ; they
terminate near the mouth, iu some insects
the ducts previously expanding into a reser-
voir.

A distinct liver is not present in insects,
its function being performed by the glandular
cells in the walls of the true stomach. In
many insects, csecal appendages arise from
the latter, and also contain cells which se-
crete a biliary liquid.

In some insects the small intestine is fur-
nished with glandular appendages in the
form of tubular caeca, probably representing-
a pancreas.

Intimately connected with the digestive
and assimilative process is a curious organ
called the fatty body. This attains its maxi-
mvmi of development towards the end of the
larval period of existence. It consists of a
number of fat- cells imbedded in a reticular
or lamellar tissue (PI. 3-5. fig. 28), composed

2f

INSECTS.

[ 434 ]

INSECTS.

of a number of somewhat angular lobes con-
nected by narrow processes having inter-
spaces between them. These are originally
formed from rounded nucleated cells, which
have given oil" anastomosing processes (fig.
29). It is traversed by a number of slender
tracheae, and occupies the interspaces of the
various abdominal organs. Each lobe con-
sists of an outer structureless membrane,
enclosing the fatty matter imbedded in an
amorphous or granular substance. It ap-
pears to form a reservoir of noiu'ishment for
the insect during the pupa-state.

In most insects are found several slender
and elongated, mostly simple, tubularglands,
opening by simple or united ducts into that
end of the true stomach corresponding to
the pylorus (PI. 35. fig. 2 e). Their free ends
are either cfecal or imite with each other.
They are often very long, and much con-
voluted around the intestines, sometimes
presenting a varicose appearance, and di-
lated near their termination. These are the
Malpighian vessels ; and they probably per-
form the function of a kidney, uric acid
having been found in them. They are
usually yellowish or brownish, and consist
of a homogeneous outer coat lined with
epithelial cells. Some authors, however,
consider that the renal organ is represented
by one or more long vessels convoluted
upon the colon and opening close to the
anus ; and we have foimd in the cater-
pillar of the fox moth, Lasiocampa ruhi,
numerous long convoluted tubes, of a
milk-white colour, filled with octahedra
and prisms of oxalate of lime ; these termi-
nated in the rectum close to the anus by
very slender ducts, whilst at the upper ends,
which reached to about the anterior third
of the body, they were coiled upon them-
selves, or united with each other.

Other glandular or secreting organs also
occur in insects. Thus organs correspond-
ing to thecutaneous glands of theVertebrata
are often met with as rounded glandular
cysts diffused beneath the integument, and
called glandulfe odoriferse ; they open at the
junction of the segments of the body, or at
the joints of the legs, by very short ducts,
and pour out a strongly-smelling secretion.
Spauldiug describes in the mentum of the
bee, a spiral duct connected with certain
glands situated in the thorax. In other
insects, similar organs are concealed at the
posterior end of the body, and pour out
their secretion near the anus. Among the
Hymenoptera, the females are often fur-

nished with a glandular apparatus which
secretes the poison of the Sting.

Spinning oryans. A large number of those
insects which undergo perfect metamorpho-
sis are furnished in the larval state with
spinning organs, with the secretion of which
many larvae, before entering the pupa-state,
weave a cocoon or enclose a cavity in which
to pass their period of rest, while'others use
this secretion for agglutinating foreign
bodies to serve the same purpose. The
glands secreting the silk consist of two long,
tubular caeca (PI. 34. fig. 16), which in a
more or less coiled state occupy the sides of
the bod}', and terminate anteriorly in two
narrow excretory ducts, dilated to form a
reservoir, and the common orifice of which
opens outside the mouth on a short tubercle
beneath the labium. The caterpillar is able to
compress the silken threads by the contrac-
tion of an angle formed by the two capillary
tubes at their point of union, and is thus
enabled to suspend itself by the threads.
The material of the silk is always colourless,
and derives the colour which it presents in
certain instances from a varnish secreted in
the reservoirs, and issuing along with the
former.

The heart in insects exists as a long con-
tractile dorsal vessel, constricted at intervals.
This terminates posteriorly in a blind end,
and is narrower in front. The posterior
portion performs the functions of a heart,
whilst the anterior represents an aorta, and
conveys the blood from the heart to the
body. From the mouth of the aorta the
blood passes without any vascular walls, in
regular currents taking all directions, and
running into the antennae, the extremities,
the wings, and other appendages, returning
as a venous current. The blood finally
forms two principal lateral currents di-
rected towards the end of the abdomen,
and, accumulating in the neighbourhood of
the heart, is brought by its diastole through
the lateral valvular tissues existing in it,
whence it is again driven through the aorta
as before. The walls of the dorsal vessel
consist of longitudinal and transverse fibres,
surrounded externally by a very delicate
peritoneal layer. The cavity of the heart is
lined by another delicate membrane, which
in the constricted parts forms internal val-
vular projections, whereby the dorsal vessel
is divided into as many chambers as there
are constrictions. Each of these cardiac
chambers is fui-nished at its front end, right
and left, with a fissure which can be closed

INSECTS.

C 435 ]

INSECTS,

internally by a valvular membranous Ibid.
The cardiac chambers contract in regular
succession from behind forwards, and thus,
with the aid of the valvular apparatus, which
prevents the lateral exit of the blood, pro-
pel this liquid into the aorta. This is no-
thing more than a continuation of the most
anterior heart-chamber, and runs as a simple
narrow tube beneath the back of the thorax,
where it terminates either in a single aper-
ture, or divides into several shoi't branches,
■which also terminate suddenly in open ori-
fices. The number of chambers varies ; but
very frequently there are eight.

In the antennae, legs, and other appen-
dages of the body of insects, the arterial and
venous currents may be seen running toge-
ther, whilst in the wings the currents are
distinct.

Minute capillaries have been detected very
generally diffused.

The blood of insects usually consists of a
colom'less liquid containing rounded or oval,
colourless, nucleated corpuscles (PL 49. fig.
33) ; but sometimes it is yellowish or green-
ish, and rarely red.

The respiration of insects is efifected by
means of Trachea, two or more large
trunks of which usually traverse the body
longitudinally , giving off branches which run
in all directions, and communicating with
the air by numerous short tubes, connected
at or near the sides of the body with orifices
termed Spiracles or stigmata. Of those
insects which live in water, some have stig-
matic orifices which are brought into rela-
tion with the air at the surface of the water ;
whilst others in the larval state respire the
air mixed with the water in which they live,
this process being facilitated by the presence
of external branchiae, or processes of the in-
tegument in the form of leaves, plates, or
hairs, through which nimierous tracheae
ramify in every direction.

The nervous system of insects consists
essentially of a series o f ganglia arranged in
pairs, one for each segment of the body, and
situated between the alimentary canal and
the under surface of the body. The ganglia
of each pair are mostly united with each
other, but sometimes distinct, and are con-
nected with those adjacent by longitudinal
cords. The uppermost pair of ventral ganglia
are connected by two lateral cords surround-
ing the oesophagus with a large cephalic gan-
glion or brain. From the ganglia branches
are distributed to all parts of the body. A
sympathetic system of nerves is also present.

Want of space compels us to limit the
notice of the reproductive organs to the de-
scription of PI. 34. figs, 18 & 19.

Many insects undergo complete metamor-
phosis, between the period at which they are
hatched and that at which they attain their
full development. On first leaving the egg,
they assume a more or less worm-like form,
known as the larva, caterpillar, or maggot.
The next stage is that in which they usually
neither move nor take food, when they form
the nympha, pupa, or chrysalis. This state
is succeeded by that of the perfect insect
or imago. In other insects, however, among
the Orthoptera, Hemiptera, and Nem-optera,
the metamorphosis is incomplete, the body,
legs, and antennae of the larva being nearly
similar in form to those of the imago, but
the wings are wanting. In some insects,
also, of the above orders, the pupa con-
tinues to be active, differing only from the
lai-va in itslarger size, and in having acquired
rudimentary wings (PI. 35. figs. 15, 17, 21),
In some insects the only change consists
in ecdysis, without material alteration in
structure. Parthenogenesis occurs; and
some larvae reproduce.

Uxcunination, ^c. The external parts and
organs of insects are usually examined as
opaque objects, the animals being held in
the stage-forceps. This method, however, is
often very unsatisfactory ; and the best 'is
to press them as much as possible between
two slides, without crushing, and to fasten
the slides together with india-rubber bands
or fine strhig, so that the parts may dry in
the compressed form. When subsequently
soaked in oil of turpentine, and mounted in
balsam, they will become much more trans-
parent and distinct. By prolonged macera-
tion in turpentine, the whole of the pigment
may be removed, which causes the structure
to be seen very distinctly. When the organs
are very hard and thick, they may be softened
by boiling water, or solution of potash,
before being pressed between the slides.

The internal organs, which are very deli-
cate, must be brought to view by dissection
under water, the insects being fixed by pins
stuck into the leaded cork (Introduction,
p. xxvii).

The smaller and more delicate insects,
aquatic larvae, &c. "are best preserved in so-
lution of chloride of calcium or glycerine,
mounted in suitable glass cells.

To preserve insects for the future exami-
nation of the internal structure, they should
be kept in solution of chloride of zinc; but

2f2

INSECTS.

[ 436 ]

INSECTS,

•wten very soft and fragile, they may be kept
in spii'it and water.

Insects are divided into eleven orders,
thus •. —

Ord. 1. Coleoptera (Beetles). Wings four,
anterior hard, coriaceous or horny (elytra),
covering the posterior, which are mem-
branous and transversely folded ; mouth
formed for manducation, furnished with
mandibles, maxillae, and palpi, both labial

Fig. 362.

Cerambyx sedilis.
Nat. size.

Fig. 363.

and maxillary ; metamorphosis complete
(fig. 362).

Ord. 2. Orthoptera (Grasshoppers, Crickets,
&c.). Wings four, the upper coriaceous,
veiny, the inferior membranous, longitu-
dinally plaited like a fan ; mouth serving
for manducation, with strong mandibles ;
maxillae furnished with a cylindrical hel-
met ; metamorphosis incomplete,

Ord. 3. Hemiptera (Bugs, &c.). Wings
four, all membranous, or the anterior ones
coriaceous at the base, and thicker; mouth
with a jointed rostrum (labium), en-
sheathing setae (mandibles and maxillae) ;
palpi none ; metamorphosis with few ex-
ceptions incomplete (tig. 363).

Ord. 4. Neuropi era (Lace-wings, Dragon-
flies, &c.). Wings four, membranous, ge-
nerally pellucid, reticulated, naked, very
often equal ; mouth not suctorial, but
mostly made for manducation ; mandibles
in some obsolete ; females never furnished
with a sting, and but rarely with a
borer or exserted oviduct ; metamorpho-
sis mostly incomplete, in some complete
(fig. 364).

Ord. 5. Lepidoptera (Butterflies, Moths).
Wings four, membranous, covered with
coloured scales ; mouth furnished with
an involute, spiral tongue, composed of

Fig. 364,

BeduTins tuberoulatus.
Nat. size.

Libellula depress*.
Nat. size.

INSECTS.

[ 437 ]

INSECTS,

the elongiited maxillas ; metamorphosis
complete (fig. 365).

Danais Pleiippe.
Nat. size.

Ord. 6. Hi/menoptera (Bees, Wasps, &c.).
Wings four, membranous, posterior ones
smaller, and with fewer veins ; maxillae
elongate, generally slender, sheathing the

Tenthredo nassata.
Jlagnified 2 diameters.

labium ; abdomen of the females almost
always terminated by an ovipositor or a
sting; metamorphosis complete (fig. 366).

Ord. 7. Diptera (Flies). Wings two, with
alulets at the base ; twohalteres; mouth
suctorial; labium not furnished with palpi,
prolonged into a proboscis or sheath, and
enclosing setse variable in number ; maxil-
lary palpi two, at the base of the pro-
boscis ; metamorphosis complete.

Ord. 8. Strepsiptera or Rhipiptera. Males
with fom- wings ; anterior wings two small
moveable corpuscles ; posterior wings
large, membranous, in the form of a qua-

drant of a circle, longitudinally folded like
a fan. Females apterous, vermiform,
without legs. Metamorphosis complica-
ted ; mandibles two, narrow, somewhat
curved ; palpi two, biarticulate, far apart,
inserted beneath the head (larvte, pupae,
and females living parasitically in Hyme-
nopterous insects).
Ord. 9. Suctoria or Siphonaptera (Fleas).
Wingless ; metamorphosis complete ;
mouth suctorial ; rostrum composed of two
serrated laminae and a thin suctorial seta,
included in a jointed two-valved sheath.
Ord. 10. Anoplura or Parasitica (Lice, PI.
35. figs. 3-8). Wings absent ; not under-
going metamorphosis ; parasitic (eyes two,
simple, sometimes none).
Ord. 11. Thysanura. Wings absent; not
undergoing metamorphosis ; not parasitic ;
mouth furnished with mandibles and
maxillae ; eyes simple, in two groups ;
abdomen mostly terminated by setae or a
bifid tail.

BiBL. Newport, Todd's Ci/cl An. and
Phys. art. Insects ; Kirby and Spence, Intr.
Entom. ; Burmeister, Entom. ; Ne-\vman,
Insects ; Siebold, Veryl. Anat. ; Straus-
Durckheim, Cons. gen. s. VAnat. d. Anim.
articid. ; Westwood, Introd. ; id. Butterflies
of Great Britain ; Stephens, Brit. Beetles,
and Br. Entom. ; Spry and Shuckard, Br,
Coleopt. ; Kirby, Man. Aimm ; Curtis, Br.
Entom. ; Panzer, Deutsch. Insekt. ; Walker,
Insecta Brit. ; Fabre, Ann. Sc. Nat ser. 4.
vii. ; Ganin, Zeitschr. wiss. Zool. 1869 ;
Kowalevsky, Mem. VAcad. St. Petersh. xvi.
1871 ; Douglas and Scott, Hemip. Heter.,
Bay Sac. ; Schultze, Q. M. Jn. 1808 ; Lan-
dois, Schidtze's Archiv, 1867 ; Lyonet, Ann.
&'c. Nat. ser. 2. t. v. ; Ratzeburg, Forst-
Insekt. 1844 ; Lacaze-Duthiers, A7m. Sc.
Nat. ser. 3. t. xix. ; Gerstaecker, Klass. nnd
Ordnung. ; Weismann, Dipter. ; Herold,
Schmetterl. ; Metschnikow, Zeit. wiss. Zool.
B. xvi. ; Leydig, Hist. ; Gegenbauer, Vergl.
Anat. 1878 ; Scudder, Tr. Smith. Inst. ;
Hicks, J. Linn. Soc. i. 136; id. Linn. Tr.
xxii. 141, xxiii. 189; T. West, Linn. Tr.
xxii. 393 ; Hepworth, Q. Mic. Jn. ii. 158 ;
Packard, Mem. Acad. {Peabody) Entomol. ;
Charpentier, Orthopt. ; Fischer, Orthopt.
Europ. ; Wolff, Riechorg. Biene 8fC. 1875 ;
Watney, Jn. M. Soc. 18^7, xvii. 213 ; Frey,
Lepidopt. Schweiz, 1880 ; Koppen, Injurious
Insects, Russia, 1880 ; Brehni, Insect. 1881,
1500 figs. ; Newman, Br. Moths and But-
te?^. ; Wilson, Larv(S of Br. Lepid., figs. ;
Lowne, Phd. Tr. 1878, 577, eyes; Minot,

INSILELLA.

[ 438 ]

INTESTINES.

Arch. Phys. 1876, trachece ; Adolpli, Inseht-
Flilgd, If^SO ; Spauldiug, Amer. Nat. 1881,
XV. 113 {Jn. M. Soc. 1881, 442) ; Dritl,
Zeitschr. wiss. Zool. 1876, xxvii., brain;
M'Lachlan, JEnc. Brit. 1882, xiii. 141.

INSILEL'LA, Ehr.— A genus of Diato-
macese.

C/iar. Frustiiles single, fusiform, with a
turgid ring (hoop ?) interposed between the
valves, which are equal ; = a terete Biddul-
phia. Marine.

I. africana. Frustules with four constric-
tions, broader and subglobose in the middle,
diminishing in size towards the acuminate
ends ; no markings visible by ordinary illu-
mination ; length 1-530 ; on the coast of
Africa.

BiBL. Ehr. Ber. Berl. Ah. 1845, 357;
Kiitz. Sp. Ah/. 32.

INTERCELLULAR Passages, Spaces,
&c. OF PX/ANTS. — Where the cells of vege-
table tissue are of any but six- or twehe-
sided forms, interspaces must exist between
them. These are especially evident in pa-
renchyma formed of rounded cells, where

Fig. 368.

Vertical section of half a leaf of a Potamogeton, with
air-8paces I.

Magnified 200 diameters.

there exist of course, angular intercom-
municating intercellular passat/es. The
stomata of Lea'vtis always communicate
with such intercellular passages, larger in
the lower part of the parenchyma of leaves.
Intei'cellular spaces are lacunae of larger
size, definite or indefinite in form, bounded
by a number of cells of less capacity than
the space itself. These are especially large
and abundant, as air-receptacles, in aquatic
plants, both in the stems and leaves, as in
the Nymphtcaceae, Naiadacese (fig. 368),
and Hydrocharidacea;, Sec, but also com-
mon in most Monocotyledonous plants, such
as JuncacejB (PI. 47. fig. 18), Araceae,
Grasses, &c.

Intercellular spaces and canals likewise

serve as Receptacles for Secretions, as
in the case of the glands of the Aui-antia-
cea3 (fi^. 280) (see also Glands), and the
turpentine-canals of the Coniferae. The
milk-vessels of plants appear to be formed
sometimes in intercellular canals, sometimes
out of cells (Laticiferous Tlssue).

BiBL. "Works on Structural Botany.

INTERCELLULAR SUBSTANCE of
Plaxts, or Secondary Cell-deposits.
— When we make fine sections of many
kinds of cellular structure, as for instance
of the horny albumen of the seeds of Palms
(Arecn, PI. 47. fig. 21) or other plants, of
the coUenchymatous tissue beneath the epi-
dermis of the Chenopodiacese &c., of the
substnnce of cartilaginous Algae, of many
woods, &c., we find an appearance of inter-
vals between the lines bounding the com-
ponent cells, which intervals are filled up
with apparently homogeneous substance.
Thus seen and no further investigated, the
interposed matter was formerly described
as intercellular substance, a peculiar form of
vegetable organization ; and some went so
far as to imagine that cells originated free
in this, and subsequently became glued to-
gether and fixed by the sohdification of the
whole (linger aud"Eodlicher). The appli-
cation of dilute sulphuric acid to prepara-
tions of this kind, with iodine, generally
shows clearly that the supposed intercellu-
lar substance consists of secondary deposits
really inside the cells (PI. 47. fig. 22). Re-
cent observations go to prove that the
supposed intercellular substance, a matter
secreted or otherwise produced between the
cells' of a tissue, is of very rare occurrence,
even if existing at all. Probably the
appearance is produced by modification of
the cell-wall. See Epiderjiis, Secon-
dary deposits. Wood, and Albumen.

BiBL. Mohl, the BiBL. of Cell-mem-
brane ; Unger, An. u. Phys. Pfl. 1846, 18 ;
Mulder and Harting, Phys. Chem. ; Hartig,
Ann. Sc. Nat. 2 ser. v. ; Wigand, Intercdl.
Sub.it. 18-50; Cohu, Linna-a, xxiii. 337,
18-jO ; Schacht, Pflanzenzelle, Berlin, 1852,
76 ; Bentley, Bot. ; Henfrey-Masters, Elem.
Course.

INTESTINES.— The intestines consist
of three coats : an outer, peritoneal, or
serous membrane, an inner or mucous mem-
brane, and an intermediate muscidar coat.

The connective tissue of the mucous
membrane is often indistinctly fibrous,
especially its inner portions, where it forms
the basement membrane ; it contains scat-

INTESTINES.

[ 439 ]

INTESTINES.

tered, roundish, elongate nuclei, -without
elastic tissue. Between the proper mucous
membrane and the submucous tissue, is
situated alayer of lono-itudinaland transverse
unstriped muscular tibres, frequently, how-
ever, indistinct in man.

Fig. 369.

Magnified 60 diameters.

Perpendicular section of the wall of the lower part of
the ileum of the calf: a, villi ; 6, Lieberkiihn's glands,
c, muscular layer of the mucous membrane ; d, follicle
of a Peyer's gland; e, subjacent portions of the submu-
cous tissue ; /, ciroiilar musciilar fibres ; g, longitudinal
ditto.

The epithelium of the intestines consists
of a single layer of cyUndrical cells, con-
taining a transparent oval nucleus, with one
or two nuclei, and granular tnatter.

In the small intestines, the free border of
the epithelium-cells presents a broad seam
with delicate longitudinal stria?, forming
the so-called pore-canals. Besides the
ordinary cylindrical or columnar cells are
certain cup-, or goblet-shaped cells, the open
mouths of which are directed towards the
cavity of the intestine (PI. 53. fig. 20). It

is a question whether these goblet-cells are
modified epithelium-cells, or represent pe-
culiar morphological elements.

The surface of the small intestines is
covered with V1X.LI, which are absent in the
large intestines ; and in every villus one or
two spaces are found, constituting the origin
of the lacteals.

The elements of the muscular coat are
unstriped muscular fibres, consisting of pale,
homogeneous, fusiform, flattened cells, with
an elongated nucleus. The fibres fre-
quently present knotty expansions, and
sometimes zigzag flexuosities.

The glandular organs of the small intes-
tines consist of : — Brunner's or the racemose
glands ; Lieberkiihn's follicles or the tubular
glands ; Peyer's, the aggregate or agminate
glands ; and the solitary glands or follicles.

Brimner's glands are situated in the sub-
mucous tissue of the duodenum, extending
about as far as the orifice of the choledic
duct. If a portion of the intestine be kept
stretched, or distended with air, and the
muscular coat be dissected off", they are seen
as yellowish, fiattened, roimdish-angular
bodies, mostly about 1-50 to 1-25" in size,
the short ducts of which pass through the
mucous membrane. They secrete an alka-
line mucous liquid.

Lieberkiihn's follicles, or the tubular
glands (fig. 370), are distributed throughout

Fig. 370.

Magnified 60 diameters.

Lieberkiihn's follicles, from the pig : a, basement
m.embrane and eijithelium ; b, cavity.

the small intestines, extending through the
substance of the mucous menibrane. They
are very numerous, straight, narrow, slightly
dilated at the ends, and rarely bifurcate.

INTESTINES.

[ 440 ]

INTESTINES.

They vary in length from 1-60 to 1-84", and
consist of a delicate basement membrane,
lined -with epithelium.

Peyer's glands are rounded or elongated
flattened aggregations of glands, appearing

Fig. 371.

Magnified 10 diameters.

Portion of a Peyer's gland, human : a, follicles sur-
rounded by the orifices of Lieberkuhn's glands ; b, villi ;
c, scattered Lieberkiihu's glands.

upon the inner side of the intestine as
slightly depressed spots. They are most
numerous in the ileum, but are sometimes
found in the lower part of the jejunum, or
even its upper part and the duodenum.
They are usually twenty, thirty, or more in
number. They vary in length from 1-25
to li". Each consists of an aggregation of
closed and rounded follicles, from 1-70 to

IM^^

Solitary gland, covered with villi, from the jejunum.

1-12" in diameter, partly seated in the mu-
cous membrane itself, partly in the sub-
nuicous tissue. The follicles are surrounded
by a ring of Lieberkiihn's glands, which,
with villi, also occupy the intervening por-
tion of the mucous membrane. Each fol-
licle consists of a tolerably iirmcoat of
indistinctly tibrous areolar tissue, with scat-
tered nuclei, enclosing a grey soft sub-
stance consisting of innumerable nuclei and
cells, from l-;5000 to 1-1500" in diameter,
with a few granules of fat. The follicles
are surrounded by a vascular network, which
sends oil" branches to their interior.

The solitary glands agree in structure
with the individual follicles of Peyer's
glands. Their free surface is usually con-
vex, and covered with villi (fig. 372).

The glandular organs of the large intes-
tines are Lieberkiihn's glands and the soli-
tary follicles.

The Lieberkiihn's glands agree in struc-
ture with those of the small intestines,
except that they are larger and broader in
proportion to the greater thickness of the
mucous membrane. The solitary follicles
also differ from those of the small intestine

Fig. 373.

%

'i <i

Magnified 45 diameters.

Solitary follicle from the colon of a child : a, tubular
glands; b, muscular coat of the mucous membrane ; c,
submucous tissue ; d, transverse muscular fibres ; e, pe-
ritoneum ; f, depression in mucous membrane over the
follicle g.

in their larger size, and in the circumstance
that each of the minute elevations of the
mucous membrane produced by them
exhibits a rounded or elongated opening,
a depression in the mucous

leading to

membrane over the follicle (fig. 373). Tliis,
however, has no communication with the
follicle.

Tlie investigation of the stnicture of the
intestines is a matter of some difficulty.
The epithelium must be examined in a
perfectly fresh state. The glands are
most readily seen in portions hardened by
absolute alcohol or cJiromic acid ; whilst
some have recommended boiling with acetic
acid (80 per cent.), then drying and making
sections with a V^ilentin's knife. The
muscular elements are rendered most di-
stinct by maceration with dilute nitric acid
(20 per cent;).

INULINE.

[ 441 ]

ISARIA.

The capillaries of tlie intestines are very
beautiful when injected ; hut great care is
required in securing the vascular branches,
to prevent the escape of the injection.

Two thick layers of ganglionic nervous
masses are distinguislmble in the intestines.
One is situated in the submucous tissue, the
other between the circular and longitutliual
muscular fibres. The former is a fiat layer
with a few ganglia projecting towards the
mucous membrane and penetrating among
the follicles; the latter is more irregular,
and presents nodulated ganglionic masses.
The ganglia give ofi" and are traversed by
nerves that form a plexus, some joining the
ganglionic layers, others uniting with the
mesenteric nerves. The nerves are non-
medullated.

BiBL. Kiilliker, Mikr. Anat. ; Verson,
Strieker's Hist. ; Frey, Hist., (^- the full
literature.

IN'ULIXE.— A substance allied to
starch, occurring in solution in the cell-
contents of plants, especially the Compo-
sitae, as the Dahlia, dandelion, &c. ; it is
coloured yellow by iodine. It forms crys-
talloids or sphaerocrystals resembling those
in PI. 39. fig. 11; "^and they exhibit the
black cross with polarized light. In a
section of a tuber of the Jerusalem arti-
choke, macerated in spirit, they will be
foimd in the cells, and may be mounted in
glycerine.

BiBL. Gmelin, Cliemie, vii.; Prautl, /;»///«,
1870; Dragendorfi; Material. 8fc., 1870;
Sachs, Bot. 1874.

IODINE. — Solution of iodine is often
useful for dyeing and rendering very trans-
parent objects more distinct, and for its
producing with some vegetable and animal
tissues and substances colours by which
they may be distinguished. The general
results of its action are enumerated in the
Introdlx'tion ; and special remarks are
made under the heads of the tissues.

An aqueous solution of iodine is the best
for general use ; but a solution in spirit is
much stronger. A very strong solution may
be made by dissolving iodine in a solution
of iodide of potassium ; this may be used
for dveing tissues, but not for the detection
of cellulose, as the precipitated iodine gives
a bluish tinge to the structure. Solutions
of iodine in chloride of zinc, and of iodide
of zinc are valuable reagents for cellulose.
See Schultze's Test.

Iodized serum is made of amniotic fluid
(calf) and a small quantity of strong tincture

of iodine. It has a pale yellow tint. It is
used as but little altering the appearances
of delicate objects.

An artificial substitute may be made
with 1 oz. of white of n^^, 30 grs. of salt,
8 oz. of water, enough tincture of iodine to
colour, and 2 or 3 drops of carbolic acid, the
whole to be well shaken and filtered.

IRID^E'A, Bory. — A genus of Cryptone-
miacepe (Florideous Algae), containing one
common British species, I. edulis, a dull-red,
obovate, leaf-shaped sea-weed of fleshy-car-
tilaginous texture, 4-18" long, the central
substance composed of longitudinal, the
cortical of closely-packed moniliform per-
pendicular filaments. Fructification : sj307-es
in spherical masses [favellidia), imbedded in
the frond in wide patches near the extre-
mity ; tetraspores in dense band-like im-
mersed sori.

BiBL. Harvey, Mar. AUj. 160, pi. 19 A ;
Phjc. Brit. pi. 97; Greville, Alg. Brit.
pi. 17; Eng. Bot. pi. 1.307.

IPtlDES'CENCE. See Intkoduction,

p. XXXV.

IRIS. See Eye, p. 311.

ISARIA, Hill. — A genus of Isaeiacei
(reputed Hyphomycetous Fungi), growing
upon dead insects, fungi, or twigs or leaves
of plants. I. farinosn, Fries, grows to a
height of 1-2" on dead pupte, spiders' nests,
&c. /. arachiwphila, Ditton, intricata, Fr.,
puherula, Berk., and Friesii, Montague, are
also British, /. citrina (figs. 374, 375) is a

Fig. 374.

Isaria citrina. Plants on a fungus. Natural size.

small species, growing gregariously on ve-
getable substances.

Tulasne has recently published an inter-
esting paper on Isaria, showing that at any
rate some of the forms referred to this genus
are conidiiferous fruits of certain Sphcerice —
in particular that Is. crassa (farinosa, Fr.)
is a form of Spha-ria inHitaris. This plant is
found most frequently on the larvas of Bo77i-
hyx Buhi; and the first sign of its growth is
the formation of a mildew, between the
rings of the abdomen, very much resembling
a Botrytis. Subsequently the body of the
larva, quite filled up and rigid with mycelial

ISAKIACEI.

C 442 ]

ISOETES.

growth, bears the claviform receptacles of
Isaria ; and at a still later period, some of
the larvse hear the claviform receptacles and

Fig. 375.

Isaria citrina. A single plant, showing the fruit.
Magn. 20 diams.

the conceptacles, containing asci, ofSphceria
miUtaris. The spores (or conidia) of the
Bofri/tis-form and of the Isaria-iovm. are
capable of germination.

BiBL. Berk. Hook. Br. Fl. vi.pt. 2. 464;
Ami. N. U. i. 2o9, vi. 132, pi. 12. fig. 12,
1850, V. 464; Fries, Su7nma Veget. 464;
Moutagne, Ann. So. Nat. 2 s^r. v. pi. 12.
fig. 3 ; Tulasne, Ann. Sc. Nat. 4 ser. viii. 35.

ISARIA'CEI.— A family of Hyphoniyce-
tous Fungi, growing on decaying animal
substances or larger Fungi, characterized
by a cellular receptacle formed of fila-
ments approximated together and conjoined
throughout their whole length, each fila-
ment terminating in a spore. Recent ob-
servations throw doubt on the independ-
ence of this family, which perhaps consists
simply of conidiiferous forms of other genera.

British Genera.

Isaria. Receptacle clavately branched,
formed of densely interwoven coalescent fila-
ments, or cellularly fleshy. Spores borne on
simple sporophores arising on all sides.

Ant.hina. Receptacle clavately branched,
formed of parallel filaments, loosely inter-
woven or free, feathery or villous at the
summit only, where they form the simple
sporophores.

Ceratium. Receptacle somewhat^ horn-
shaped, of a mucilaginous consistence,
sprinkled with filaments which are sur-
mounted by naked spores.

I'SIAS. — A genus of Copepodous Ento-
mostraca. I. davijjes, in British seas.
(Brady, Copepoda, Bay Soc. i. 62.)

ISINGLASS.— This material consists of
finely-divided shreads of the swimming-
bladder of species of Sturgeon, and con-
sequently exhibits structure under the mi-
croscope, consisting of a fibrous tissue with
here and there fragments of blood-vessels
&c. It is sophisticated with cut gelatine,
which is structureless and moreover becomes
more translucent when soaked in water,
while isinglass becomes opaque and white.

BiBL. liassall, Adidterations, .309.

ISOCniLI'NA, Jones.— An oblong equi-
valved Ostracode, belonging to the Leperdi-
tiadce, and found only in the Silurian rocks
of Canada, Russia, and Bohemia.

BiBL. R. Jones, Ann. N. H. 3. i. 248;
Schmidt, Mem. Acad, St. Petersh. xxi. 2,

ISOETES.— A genus of Psiloteee (Lyco-
podiacete). /. lacustris, Quillwort, the only
British species, occiu's in mountain-lakes.
Isoetes is very remarkable in its mode of

growth.

The woody substance of the stem, like
that of the Lycopodiacefe generally, is a
solid central body, without a pith ; it is
surrounded by a thick parenchymatous
rind, which makes up the greater part of
the mass of the corm ; the woodj^ mass itself
is cylindrical above, and somewhat hemi-
spherical below, the convexity downward,
and it has a layer of cambium not only over
the growing apex, but over the convexity
of the sides and lower surface. Every year
a new portion of wood is added to the
upper end, and also to the outer angle of
the convex lower mass. The roots are pro-
duced in cycles of tens, sometimes one,
sometimes two in a year ; in each cycle the
oldest root is the inmost ; but the succeed-
ing cycles appear in the middle of their
predecessors, and push them out, and up to
the side. The rind is renewed every year
by the cambium layer ; and tiie latter, in its
growth to increase the size of the corm, by
degrees covers up and encloses the remains
of the earlier roots (as the woody layers
of Dicotyledonous trees overgrow broken
branches, bury them, and convert them
into imbedded knots). The leaves are of
delicate organization, and contain four lon-
gitudinal air-canals, with septa at intervals,
and one vascular bundle ; they are expanded
at the base, and contain the immersed spo-
ranges. DeCandolle says the epidermis has
stomata. The sporanges are of two kinds,
or rather bear two kinds of spores ; and
there appears to be a periodicity in their
development. The fronds of I. lucmtris are

ISOETES.

[ 443 ]

ISOETES.

discoverable in the interior of the bud
twelve months before they became fully
developed ; the sterile originate in spring
and the earlier part of the summer, the
fertile in the autumn, wliile stunted fertile
leaves appear even in the winter. If a
vigorous leafy plant be examined, it will be

Fig. 376.

Isoetes setacea.
Natural size.

found to have a few sterile leaves outside,
then a circle of leaves with oosporanges,
next a circle of anthero-sporanges, and in
the centre of the bud sterile leaves closing
the annual cycle. The sporanges are some-
what plano-convex longish-oval cases, with
transverse processes forming imperfect septa,
dividing them into several chambers (hg.
378). The cases are sheathed by a mem-
branous expansion of the base of the leaf
(fig. 377), to which they are adherent by
the back (fig. 378) ; the septa arise
opposite the point of attachment at the
back, and, spreading out, join the front wall.
The ditiereut contents of the sporanges are
evident before they open, those with the
small spores (antJierosporanges) having a
smooth face, those with large spores {oospo-

ranges) heing rendered tubercular from the
protrusion of the wall by the underlying
bodies. The wall of tlie capsule is mem-
branous and has no regular dehiscence, the

Fig. 377.

Fig. 378.

Fig. 379.

Isoetes setacea.

Fig. 377. Base of a detached fertile leaf, seen in face.
Magn. .5 diams.

Fig. 378. Vertical section, from back to front of ditto.
Magn. 10 diams.

Fig. 379. Horizontal section, oosporange with macro-
spores. Magn. 10 diams.

spores escaping by decay of the membrane
in front.

The sinalle?- s/jo?ts resemble pollen-grains;
they are usually of the shape of quarters of
a globe, more rarely tetrahedral, with an
outer coat presenting ridges at the angles,
and an inner which is a rounded sac. The
outer coat is finely dotted in /. laeustris.
The large spores are at first of a tetrahedral
form with rounded angles, but when ripe
they become globular. The delicate inmost
layer is enclosed in a thick exospore com-
posed of three layers: — the innermost of mo-
derate thickness, brown colour, and glassy
consistence, exhibiting strife and three
strong ridges converging to a point at the
angle where the spore meets its three sister
spores ; the next coat is thinnish, and of
granular character and yellow colour ; the
outermost is a clear and gelatinous layer :
the outer two follow all the markings of
the glassy coat, and are especially thick
over the three ridpres.

ISOETES,

[ 444 ]

IXODES.

The contents of the microspores are at
first merely granular protoplasm. About a
month after they are scattered from the
sporange, the protoplasm of the cell becomes
divided into two or four portions, which
form cells, in each of which again are de-
veloped two vesicles, each producing a fila-
ment coiled up spirally. The spores swell,
the daughter cells burst, and the lenticidar
vesicles escape ; the latter then open and
emit the spiral filaments, which are found
to be covered with cilia on the anterior
turns of the spiral, by means of which they
move actively through the water. They are
the spermutozoids.

The macrospores when they escape from
the sporange, contain only protoplasm with
oU-giobules. In the course of a few weeks,
the internal cavity of the spore begins to
exhibit a development of cellular tissue, by
■which it is subsequently filled up; this is
the prothaUiuni. At the same time, the in-
ternal coat increases in thiclmess, and ex-
hibits several layers. The increase in size
of the prothallium causes the spore-coat to
burst at the apex where the three ridges
meet, so that three triangular vahes turn
back, exposing the prothallium. On this
are developed the archegonia, the first on
the apex in the central point where the
three points of the spore-coat meet. If this
is not fertilized, others are produced around
it. The archegonium is of much the same
character essentially, as that of the rest of
the higher Cryptogamous Plants, consisting
of a papilla with a central canal leading to
the embryo-sac. The four rows of cells
forming the neck of the archegone separate,
and a germ-cell is formed in the embryo-
sac. This is fertilized by the entrance of a
spermatozoid into the embryo-sac.

In the development of the embryo in the
spore, it forms a cellular body, which gra-
dually displaces the cellular tissue originally
filling this up. The first leaf and roots are
developed while the rudiment is still within
the spore-coat, in opposite directions, and
horizontally (right and left) in relation to
the apex of the spore. The young plant
somewhat resembles a germinating JNIono-
cotyledon.

The woodv structure of the stem of Isoetes
consists of spiral-fibrous cells, usually annular
or reticulated, but sometimes really spiral.

Carruthers has explained the resemblance
of the method of the growth of Isoetes and
that of the gigantic Lepidodendron of the
Carboniferous deposits.

BiBL. BischofF, Crypt. Gewdch. lihizoc.)
Nuremberg, 1828,70; Mohl, Verm. Schrift.,
Tubingen, 1845, 122 ; Miiller, Hot. Zeit. vi-
297, 1848 {Ann. N. H. 2 ser. ii. 81);
Mettenius, Beitr. z. Bot. Heidelberg, 1850 ;
Hofmeister, ^/V*. s«c/(,5. Ges. d. Wiss.iv. 123 ;
Braun, Flora, 1847, 33; Carruthers, Led.
Roy. Inst. 1869 ; Henf rev-Masters, J5o^. 1878.

iSOT'RICHA, Hein.— Agenus of Holo-
trichous Infusoria= 0;9«/m« with a ventral
mouth. In the rumen of ruminants.
(Kent, Inf. 497.)

ISTII'MIA, Ag.— A genus of Diato-
macese, fam. Biddulphiacete.

Char. Frustules depressed or subcylindri-
cal, rhomboidal or trapezoidal in front view,
angles more or less produced ; frustules co-
herent by the angles, basal frustule stipitate ;
surface of valves and hoop appearing reticu-
lar or cellular. Marine. Two British species.

The depressions upon the valves and
hoop are so large as to produce a distinct
reticular or cellular appearance when viewed
by ordinary illumination.

/. obliquata {nervosa, K.). V. with linear
thickenings, giving them a coarsely reticular
or veined appearance.

I. enervis (PI. 17. fig. 2). Valves uniformly
covered with depressions.

BiBL. Ehr. Inf. 209 ; KUtz. BacUl. 137,
and Sp. Ah/. 135 ; Ralfs, Ann. N. U. 1813,
xii. 270 ; Rabenh. Alg. i. 309.

ITCH-INSECT. See Sarcoptes.

IVORY. — This substance, which consists
of the tusks of the elephant, possesses the
minute structure of the ivory of teeth.

IVORY, Vegetable. — This substance,
consisting of the albumen of the seeds of
a Monocotyledonous tree, Phijtelephas ma-
crocarpa, is composed of cellular tissue, with
the walls so thickened by horny secondary
deposits that the cavities of the cells are
almost obliterated. The pores of the se-
condary deposits, however, remain unco-
vered throughout all the thickening, and
thus are converted into tubes or canals run-
ning to meet each other from the small re-
maining cavities of contiguous cells. In
PI. 47, fig. 23 h represents a section mounted
in Canada balsam, which has in part pene-
trated into the cavities ; the remaining ca-
vities and pore-canals are filled with air and
thus appear black {a).

IXO'DEA. — A family of Arachnida, of
the order Acarina.

Contains the genera Ixodes and Argas.

IXO'DES, Latr. — A genus of Arachnida,
of the order Acarina, and family Ixodea.

JAMESONIA.

[ 446' ]

JUNGERMANNIEvE.

Char. Palpi canaliculate, slieatliing tlie
rostrum; mandibles three -jointed, basat
joint internal, the second joint external and
long, the third short, denticulate ; labium
covered with reflexed teeth ; body very ex-
tensile, furnished near the rostruur with a
dorsal horny shield; legs with two claws
and a caruncle.

These animals form part of those which
are popularly known as ticks. They are com-
monly found in dense woods, upon brush-
wood, briers, kc, from which they get upon
animals, as dogs, oxen, horses, &c., burying
the rostrum deeply in the skin and sucking
the blood, so as to become distended to ten
times their original size. They are also
found upon reptiles, bii'ds, and occasionally
attack man.

Haller points out two foramina at the
hinder margin of the last joint of the first
pair of legs, covered with a membrane, and
with otoliths, forming an auditory apparatus.

The species are very numerous, and have
been arranged in several genera by some
authors. The following are the commonest
species : —

I. ricinvs, the dog-tick. Body oval, in
the gorged condition becoming globular and
blackish violet ; legs and appendages brown.

I. reduvws. Pale yellowish red; head
and legs black. Found upon sheep.

I. pictus. Back white, with brown
spots; creuulate posteriorly; legs brown.
Found upon deer ; also upon mosses.

I. Z/uffesii (plmnbetiSfDag.) (PI. 6. figs. 19-
22). Oval, leaden grey, without spots.
Found upon dogs.

/. plumbeus, Leach. Shield heart-shaped,
slightly rugose ; rostrum, palpi, and legs
pale ferruginous ; body of a leaden colour ;
length 1-4". Found upon and in the nests
of the bank-swallow (Hirundo riparia).

BiBL. Gervais, Walck. Aptb-es, iii. 234 ;
Hermann, Mem. Apter. : Duges, Ann. Sc.
Nat. 2 ser. ii. ; Leach, Linn. Tr. xi. ; Koch,
Uehers. ; Denny, Atin. JV. H. 184-3, xii. ;
Gene, ibid. 1846, xviii. 160; Macalister,
Qu. M. J. 1871, 166 ; MuiTav, J?c. Entom. ;
Megnin, 121 ; Haller, Zool. Anz. 1881, 165
{Jn. Mic. Soc. 1881, 449).

JAMESO'NL^, Hk.— A genus of Gram-
mitideae (Polypodiaceous Ferns). ( ne
species ; Andes. (Hooker, Syn. Fil. .369.)

JANIA, Lamouroux. — A genus of Coral-
linacese (Florideous Algae), calcareous fila-
mentous bodies, occurring in tufts, pale red

or purplish when fresh, on small Alg?e be-
tween tide-marks. The filaments are arti-
culated, dichotomously branched, and im-
pregnated with a calcareous deposit. The
fruit consists of lu-u-shaped ceramidia,
formed out of the end joints of the branches,
a dichotomous continuation of which is re-
presented by a pair of minute divergent
horns on the ceramidium ; the latter has a
pore at the apex, and contains a tuft of erect
linear tetraspores. British species :

J. ruhens. Joints of principal branches
cylindrical. Harvey, Phyc. Brit. pi. 252.

J. corniculata. Joints of principal branches
obconical and compressed, I. c. pi. 2.34.

BiBL. Harvey, I. c, and Mar. Alg. 107,
pi. 13 D.

JAT'ROPHA. See Cassava.
JONESIA, G. S. Brady, 1865.— A
marine Ostracode. See Bythocythere.

JONESIEL'LA, Brady.— A genus of
Copepodous Entomostraca.

Two British species ; in dredgings.
(Brady, Copep., Ray Soc. ii. 38.)

JULUS, Linn. — A genus of Chilopodous
Myiiapoda. J. terrestris and a few other
species are often found in gardens. •

JUNGERMANNIA, Bill.— A genus of
Jungermannieas (Hepaticse). Fructification
terminal. Perichaetial lea^t-es free or united
only at the base, like or unlike the stem-
leaves. Perigone membranous, tubular,
plaited-denticulate at the apex, the mouth
three- or six-cleft. Vaginule membranous,
included or rarely exserted. Capsule four-
valved, splitting to the base. Amphigastria
present or absent.

This is the largest genus of the Junger-
mannieaB ; among the commonest species
are J. bicusjndata, L., J. albicans, L., J. bar-
bata, J. setacea, &c., found on wet bogs,
banks, rocks, &c.

BiBL. Hooker, Br. Jungerm., Br. Flor.
i. pt. 1. 112, &c. ; Ekart, Synops. Jungerm. ;
Nees V. Esenbeck, Europ. Lebermoose ;
Gottsche, Lindenberg, and Nees, Synojis.
Hepatic, Hamburg, 1844-47 ; Stephani,
Junqerm. ( Germ. ) 1 879.

JUNGERMANNl'E^.— A family of
Hepaticse, distinguished by possessing a
distinct stem, bearing leaves, often with
stipule-like bodies called amphigastria (fig.
380), with terminal archegones, and spo-
ranges bursting by four valves (figs. 320
and 321), destitute of a columella, contain-
ing elaters mixed with the spores.

The British genera may be grouped as
follows: —

JUNIPERUS.

[ 446 ]

KIDNEY.

Fig. 380.

Jungermannia albicans.

Stem with succubous leaves and aniphigaBtria, and a
lateral unopened perigone.

Magnified 10 diameters.

1. Leaves incubous (tlieir bases covered by

tbe tips of those below).

* Leaves complicate, two-lobed.

t Ampliigastria present : Lejeunia,

Phracimicoma, FruUania, Madotheca,

Ptilidmm.
tt Amphigastria absent. Radula.
** Leaves not complicate, two-lobed.
t Amphigastria present : Trochocolea,

Sendtnera, Schisma, Herpetium, Cahj-

poyeia.
tt Amphigastria wanting. Physiotium.

2. Leaves succubous (the bases covering

the tips of those below).

* Amphigastria present : Saccof/i/na,
CheiJoscyphus, Lophocolea, Sphaynocce-
tis, Junyennannia, AJlicularia,

** Amphigastria absent: Playiochila,
Sarcoscyphus, Gymnomitrium, Jfajilomi-
trium. See the genera.

JUNIP'ERUS, L.— A genus of Coni-
fers, presenting some interesting charac-
ters in the Wood, the Pollen, and the
development of the Ovules.

JUTE. — The liher of Corchorus capsularis,
Willdenow, an East-Indian plant belonging
to the family of the Tiliaceas, so many of
which furnish fibrous substances, such as
the hast used for matting, which is the liber
of the lime-tree. Jute has a very long,
glossy fibre, and is very largely imported
into this country. PI. 28. fig. 3 represents
the single liber-tibres (see FiBEOUS Struc-
tures and Liber).

BiBL. Hooker, Jn. Bot. i. 25, 1849.

Fig. 381.

K.
KALLYME'NIA, J. Ag.— A genus of
Cryptonemiacese (Florideous Algee), fleshy
membranous sea-weeds of red colour, with
ribless leaf-like fronds, having three strata
of cellular tissue — the central filamentous,
the intermediate of large round cells, the
cortical of minute cells in vertical rows.
Fructification : spherical masses (favellidia)
of spores half immersed in the frond, and
tetraspores, which are tetrahedrally subdi-
vided, and occur scattered. The two British
species, K. reniformis and Dubyi, are both

BiBL. Harvey, Mar. Ah/. 150, pi. 19 B ;
Phyc. Brit. pi. 13. 123 ; Bnyl. Bot. pi. 2116.

KAULFUSSIA, Blume.-
A genus of Marattiaceous
Ferns, with curious roundish
sori, formed of radiately co-
herent sporanges, opening by
a slit at the top (fig. 381). KauTfusBia.
I spec, Assam (Hooker, &'yn. A sorus.

444 ) . Magn.25 diams.

KERO'NA, Mfill, Ehr.— A genus of In-
fusoria, of the family Oxytrichina.

Char. Body covered with cilia, hooks also
present, but no styles.

K. polyporum, = Stylonichia polyporurn,
(PI. 50. fig. 13). Body whitish, depressed,
elliptico-reniform, with a row of longer cilia
in front below the mouth j length 1-144",
Parasitic upon Hydra.

BiBL. Ehr. Inf. 368; Duj. Inf. 422;
Claparede et Lachm. Infus. 69, 101.

KERO'NIA.— A family of Infusoria
(Duj.), nearly corresponding to the Oxy-
trichina of Ehr.

Dujardin's family comprises Halteria,
Oxytricha, and Kerona.

KIDNEY. — The kidney consists of its
enveloping m6mbrane and the secreting
parenchpna.

The membrane is a firm fibrous coat,
called the capsule. It is composed of con-
densed connective tissue, and is continuous
with that constituting the matrix of the
kidney, in the meshes of which are the
uriniferous tubes and blood-vessels. At
the notch of the kidney, or the hilum, this
fibrous capsule is continuous with the outer
coat of the pelvis of the kidney, and also
with the sheaths of the blood-vessels.

The parenchyma, in a transverse section,
appears to the naked eye to consist of two
parts — the inner or medullary substance, and
the outer or cortical. The medullary sub-
stance is composed of 8-15 isolated conical

KIDNEY.

C 447 ]

KIDNEY.

masses or pyramids, converging towards the
hilum, and "their apices forming the papillic ;
whilst the cortical substance constitutes the
outer part of the organ, and fills up the in-
terstices between the pyramids. Micro-
scopically examined, the cortical part also
becomes'resolved into as many segments as
there are pyramids ; hence the kidneys may
be regarded as composed of a certain nimiber
of intimately connected lobnles.

Both the cortical and the tubular substance
consist principally of the minary tubules.
These commence in each segment or lobule
by very numerous orifices on the surface of
the pa*pilla3, and pass through the pyramids,

Fig. 382.

finally becoming again tortuous and enlarged
before terminating in the Malpighian cap-
sules.

383.

Papilla of the kidney of a pig with the tubules in-
ected, showing their origins upon the svirface.
Magnified 10 diameters.

running straight and nearly parallel with
each other (fig. 383 k). During this course
they undergo repeated dichotomous subdi-
vision (fig. 383 /), the branches being given
off at a very acute angle, and at first with
considerable diminution in size ; and some-
times they divide into three or four branches,
so that ultimately a larger bundle of tubes
proceeds from them, producing the increased
breadth of the p>i-amids towards the exte-
rior. Towards the base of the pyramids,
the parallel tubules become more loosely
connected by the interposition of bundles
of arteries and veins (which run straight),
and they diverge in all direetions, pui'suing
an undulating course.

On reaching the cortex, the tubules
branch ofi'and increase in diameter, becom-
ing also very tortuous ; then they turn back,
diminishing in breadth, and run parallel
with their first course, but in the opposite
direction. They then form a curve, the
loop of Henle, and run upwards again,

Perpendicular section of the injected kidney of a rab-
bit through part of a pyramid. On the left the course
of the vessels, on the right that of the tubules is shown.
a, interlobular arteries, with their Malpighian tufts b,
and vasa efferentia c ; <?, capillaries of the cortical por-
tion; e, vasa efferentia of the outermost tufts, passing to
the surface of the kidney ; f, vasa efferentia of the in-
nermost tufts, running into the straight aTterina, g, g, g ;
h, capillaries of the pyramids, arising from the latter ;
i, a sti-aight vein commencing at the papilla ; k, origin
of a urinary tubule at a papilla; I, o, branches of the
same; m, coiled portion in the cortex; n, the same at
the surface of the kidney ; p, connexion with the Mal-
pighian capsules.

Magnified 30 diameters.

The urinary tubules are cylindrical, and
usually consist of a basement membrane

KIDNEY.

[ 448 ]

KIDNEY.

(fig. 384 b) lined with pavement epithelium,
d. The b.asement membrane is very trans-
parent, but firm and elastic. Within it is a
single laj^er of nucleated polygonal epithelial
cells (fig. 384 d, e). These, when immersed
in water, lose their polygonal form, become
rounded, and appear to fill up the tubules
entirely ; they often also burst; and then
the tubules appear to contain nothing more
than a finely granular mass with nuclei.
These changes are found to have taken place

1. A Malpighian body A, with the urinary tubule B C,
human, a, Capsule of the Malpighian body, continuous
with 6, the b;i8ement membrane of the tubule ; c, epi-
thelium of the Malpighian body : d, that of the tubule ;
e, detached epithelial cells; /, afferent vessel; g, effe-
rent vessel; k, Malpighian tuft. 2. Three epithelial
cells from coiled tubules, one of them containing glo-
bules of fat.

Magnified 300 diameters.

spontaneously if the kidney is not fresh.
But the structure of the tubules varies.
Thus, in some parts of the convoluted
tubules, the nuclei ajipear imbedded in a
pulpy mass or a granular epithelium ; while
in others, clear epithelial cells exist, and
are larger than in the straight tubules. In
the tubuli of the medullary portion, the
epithelium is columnar; and in the tubuli of
the papillae the basement membrane is
ab-ont.

The Malpighian bodies may be regarded
as terminal dilatations of the tubules, ench
containing a round plexus of vessels, form-
ing the Malpighian tuft.

The basement membrane surrounding the
tuft (fig. 384 a) is somewhat thicker than
elsewhere ; and the epithelium lining it is
continued over the free surface of the tuft ; but
this is denied by Bowman. The Malpighian
tufts consist of close convolutions of fine
vessels derived from branches of the renal
artery. The latter enter the kidney between
the pyramids, and continue to divide until
arriving at the cortical substance, where
they give off" a number of long branches,
mostly running towards the convex surface
of the kidney, between the lobules, hence
called interlobular arteries. From these,
short (mostly lateral) branches are given
off", each of which terminates in a Malpighian
tuft, forming its afferent vessel. Each
afferent vessel, on entering the Malpighian
body, divides into 5-8 branches, each of

Fig. 385.

From a human kidney, a, end of an interlobular
artery; 6, aft'erent vessels; e, naked Malpighian tuft;
(?, efferent vessels ; e, tufts enclosed in their capsules ;
f, ui'inary tubules arising from them.

Magnified 45 diameters.

which becomes subdivided into a tuft of
capillaries; these are variously convoluted
and interwoven, ultimately uniting in a
single vessel, the efferent vessel. The afferent
and efferent vessels are usually situated near
each other, and opposite the origin of the
urinary tubule.

KIDNEY.

[ 449 ]

KIDNEY.

The efForent vessels, wliich, altliouu-h
arising- from the capillaries of the Malpi-
ghian tiifts, are rather small arteries than
veins, in import and partly in structure,
termiuate in the capillary network situated
in the cortical substance and the pyramids.
This network closely surrounds the coiled
tubules on all sides, and forms a connected
plexus throughout the kidney, the meshes
of which are" roundish-angular ; but near
the pvramids the afferent vessels are larger,
and dill'er from the rest in their straighter
course and more sparing ramitication.

The veins of the kidney commence on
the surface of the organ and at the apices
of the papillfe by small branches connected
with the plexus"; these by their union form
larger ones, which accompany the larger
arteries.

Bowman compares the solitary efferent
vessels of the Malpighian bodies to the portal
system of the hver, both serving to convey
blood between twc capillary systems ; and
so these efferent vessels collectively form
the portal system of the kidney.

The interstices between the vessels, nerves,
and tubules of the kidney are occupied by a
stroma of connective tissue (hg. 386 c), con-
Fig. 386.

3%

''-f

Transverse section of the cortical urinary tubules;
human, a, divided tubules, with the epi( helium re-
moved ; 6, the same, containing the epithelium ; c,
stroma of connective tissue ; d, space corresponding to
a Malpighian body.

Magnified 250 diameters.

taining elongated nuclei, and which is much
more abundant in the medullary than in the
cortical portion. At the surface this fre-
qiiently becomes condensed to form a very
distinct membrane, but loosely adherent to

the fibrous capsid(>, and which is connected
by numerous deheato processes with the
inner stroma.

The pehis of the kidney with the calyces
and the ureter consist of an outer hbroin, a
muscular, and a mucous coat. The fibrous
coat is composed of ordinary connective
tissue, mixed with elastic tissue.

The mucous coat is thin, and not fur-
nished with glands or papillas. Its epithe-
lium (tig. 387 b) is laminated, and remark-
Fig. 387,

yt. y^

Epithelium of the pelvis of the kidney ; human.

A. Isolated cells: o, small, 6, large pavement-epithe-
lial cells; c, the same containing the granules; d, cy-
lindrical and conical cells from the deeperlayers; e,
inteimediate forms. B. Cells in silu.

Magnified 350 diameters.

able for the variable form and size of ita
elements (fig. 387 a), the deeper cells being
roundish and small, tho.se in the middle
cylindrical or conical, and the uppermost
roundish, polygonal, and somewhat flat-
tened. The cells frequently contain two
nuclei, and bright rounded granules with
dark margins.

Lymphatics accompany the blood-vessels
at the hilum, and pass between the groups
of tortuous tubules in the cortex ; and the
nerves penetrate the kidney with the ves-
sels, and present ganglia in their course.

In the Mammalia generally the structure
of the kidneys agrees essentially with that
of man.

In the lower Vertebrata they exhibit

2g

KIDNEY.

[ 450 ]

KIEKBYA.

differences, which relate principally to the
following particulars : — 1, the form, which
in birds, fishes, and reptiles is considerably
more elongated, and frequently flattened ;
2, the lobulation, which in the human adult
kidney is indistinct, although marked in
tlie foetus, whilst in that of other Vertebrata
the separate lobules are very distinct, some-
times being connected only by the branches
of the ureter ; 3, the Malpighiau tufts, which
in birds, reptiles, and fishes consist of a
single convoluted vessel, and which in some
(naked reptiles) are larger, in others (osseous
fishes) smaller than in man, whilst in birds
(also the sheep) thej'- have been found
inserted into the sides of the tubules ; and
4, in the structure and arrangement of the
urinary tubules : these are uniform in size
in fishes, furnished with ciliated epithelium
in the reptiles and fishes, and pi'eseut varie-
ties in regard to the convolution, branching,
and termination in the ureter.

Renal organs have been noticed in the
Mollusca, Arachnida, and Insecta.

The epithelial cells of the urinary tubules
are not unfi'equenlly found to contain the
ordinary urinary -deposits, which are more
often still met with in the cavities of the
tubides. Many of these are probably, how-
ever, formed after death (see Ueinaey
deposits).

Among the morbid changes of the Idduey,
passing over cancer, tubercle, variations in
the degree of vascularity, the presence of
calculi, and the ordinary products of inflam-
mation, may be mentioned the occurrence
of cysts. These are met wdth of various
size and in variable number. The walls
of the cysts do not differ in structure from
those of the tubules, except in being thick-
ened; they have been accounted for as
arising from dilatation of the tubules or
Malpighian capsules, in consequence of
obstruction to the escape of the urine,
distention of the epithelial cells of the
tubules, and degeneration of their nuclei,
forming colloid cells. The first is probably
the general cause, and certainly an occa-
sional one, the Malpighiau tufls having
been found within the enlarged cysts after
injection. Sometimes the cysts are those of
JEchinucocci. In Blight's kidney the tubules
are found de^u'ived of tlicir epithelium,
the cells filled with albuminous, fibrinous,
or fatty matter, and the fibrous tissue
increased, — in the advanced stage both
becomiug undistinguishable in some parts,
whilst in others the cells and tubules are

loaded with fatty globules, producing the
well-knowai granular appearance. And in
certain cases, the kidneys become "waxy,"
the Malpighian corpuscles and intertubnlar
spaces, sometimes the tubules also, being
filled with amjdaceous corpuscles.

In examining the structure of the kidney,
sections must be made with a Valentin's
knife. The arrangement of the vessels may
be shown by injection; and the injected
preparations are very beautiful, and form
general favourites. The Malpighian bodies
are readily filled, the injection being thrown
into the artery ; and they are easily recog-
nized by their resemblance to little apples
upon the branches of a tree (PI. 39. fig. 35).
The injection should be red. If the injec-
tion be coarse, it will burst through tlie
capillaries of the tufts, and partly fill the
tubides as in fig. 383 ^j; but if it be fine,
it will fill the venous plexus. The urinaiy
tubules should be injected from the ureter,
white (lead) injection being used; and con-
siderable force is required to make a good
injection, but this mu«t be very gradually ap-
plied. Frey recommends the cold ferridcya-
nide injection, or carmine with glycerine or
gum. The tubules can be well examined by
boiling pieces of the kidney with very dilute
sulphuric acid, or in alcohol mixed with
muriatic acid ; or by digestion in cold con-
centrated muriatic acid, the pieces being
subsequently macerated in water, to remove
the acid.

The kidneys of the smaller and lower
animals are be;)t injected from the heart.
The usual staining pi'ocesses are very useful.

BiBL. Kolliker, Mik. An. ii. ; Bowman,
Phil. Tr. 1842; Johnson, Todd's Cyclop.
art. JRtn\ Toynbee,' J/(?rZ. Clii. Tr. xxx. ;
Forster, Tath. Anat. ; Frerichs, Brightsche
Nierenkranh. ; , Gairdner, Edinb. M. Jn.
viii. ; Todd and Bowman, Phys. Anat. ;
Henle, Ahh. Geselh. Wiss. 'OoUin. x. ;
Ludwig, Strieker's Ilandh. i. 489; Riud-
tieisch. Path. 1878, 434; Gross, Structure
Mic. du Rein, Strasbourg, 1868 ; Frev,
Mikr. 1881, and Tlistol. 1876, 554.

KIRK'BYA, Jones. — A small bivalved
Entomostracau, of the I^eperditiada? family,
and nearly allied to Beijrichia. The valves
ridged longitudinally and concentrically,
often reticulated superficially, and impressed
with a subcentrnl pit. Fossil in tln^ Palaeo-
zoic rocks, from the Silurian to the Permian,
and often very abundant.

BiiiL. R. Jones, Tr.Ti/nesideNat. Club,iv.
134 ; Ann. N. H. ser. 4, iii. 223.

KNIFE.

[ 451 ]

LAFOEA.

KNIFE, VALENTIN'S. Introduc-
tion, p. xxvi.

KONDYEOS'TOMA, Diij.— A geuiis of
Lifusoria, of the family Bursurina.

Char. Body elongated, cylindrical or
fusiform, slightly arcuate, the ends obtuse
and depressed, with a very large mouth
margined with stout cilia, and situated late-
rally at the anterior end ; surface obliquely
strinted and ciliated.

K. jMfcm (PL 31. fig. 31 ; fig. 32, slightly
compressed).

BiBL. Duj. Infus. 51G; Clap, et Lacli.
Inf. 244.

"KR A USE'S CORPUSCLES.— The ter-
minal bulbs of the nervous plexus and in-
terlacing nerve-tibres of tlie conjunctiva.
They consist of a connective-tissue sheath
with nuclei, au internal bulb of finely granu-
lar dull-shining material, within which is a
pale terminal fibre with a somewhat thick-
ened end.

BiBL. Krause, U. term. Korper, 1868;
Strieker, Geu-ebe, ii. 123.

KKITHE,B., C., and R. See Ilyobates.

L.

LABREL'LA, Fr.— A genus of Phaci-
diacei (Ascomycetous Fungi), growing upon
living leaves. L. Ptarmicce, Desm., grows
upon the leaves of AchiUea Ptarmica.

BiBL. Berk. Ann. N. H. i. 208, pi. 7.
fig. 7 ; Fries, Stimma J^eq. 422.

LABYRINTHODON'TA.— A group of
extinct Amphibia. Transverse sections of
the teeth of the species of this group are
beautiful microscopic objects.

BiBL. Owen, Odontography.

LABYRIN'THULA, Cieukow.— a ge-
nus or group of Protozoa. Composed of
microscopic, thin, reticular, colourless, rigid
filaments, on which fusiform bodies glide
very slowly in various directions ; the fila-
ments arise from imbedded globular red or
yellow masses. Two
posts; Odessa.

BiBL. Oienkowski, Arch. mik. An. iii.
274.

LACE-BARK. See Thymeleace^.

LACINULARIA, Oken.— a genus of
Rotatoria, of the family Floscularifea.

Char. Eyes two (when young); urceolior
gelatinous sheaths aggregated into a spheri-
cal mas,-< ; rotatory organs with two lobes.

L. socialis (PI. .50. fig. 15). Urceoli ge-
latinous, yellowish ; rotatory organ veiy
broad, in the form of a horseshoe ; fr. wat. ;
length 1-36".

species, on submerged

BiBL. Ehrenb. Inf. 403; Huxley, Mic.
Jn. 1852 ; Leydig, Siehold mid KiHl. Zeit.
18.52 ; Ukedem, Ann. Set. N. 3 st5r. 1851 j
Cubitt, 31. Mic. Jn. 1872-73.

LACRYMA'RIA, Bory.— A genus of
Infusoria, of the family Traclielina, Clap, et
Lach.

Char. Body rounded behind, not ciliated;
with a long and slender neck, which is
dilated at the end, and furnished with a
ciliated mouth and a lip, but no teeth
(= Trachelocerca without a tail).

L. proteus, syn. L. olor. Body oblong,
turgid, colourless, with delicate oblique
strise ; neck very long ; freshwater ; length
1-140".

Two doubtful species : one (Z. gutta)
colourless and without strise ; the other
(L. rugosa) containing gi'een matter, with
the body wrinkled. Claparede describes
two other species.

BiBL. Ehrenb. Inf. 309; Duj. Inf. 468;
Clap, et Lach. hf. ; Kent, Inf. 51 7.

LACTA'RIUS.— A genus' of Hymeno-
mycetous Fungi, distinguished from Agari-
cus by the inner substance of the gills
(trama) being vesicidar instead of filamen-
tous. Most of the species abound in milky
juice; and several of them are esculent.
Amongst the most approved is L. deliciusus,
remarkable for its bright orange-coloured
milk. Some acrid species, however, as L.
jnperitus, are largely consumed in Russia,
having first in general been preserved in
salt and vinegar. The milk is contained in
pecidiar vessels, similar to the laticiferous
vessels of Phanerogams. See Laticife-
rous Tissue.

BiBL. Fr. Epia: 333; Berk. Outl. 203;
Cooke, Handb. 206; Corda, Jc, fasc. 4,
pi. 10. fig. 1.30.

LACTATES. See the bases lactate of
lime (PL 11. fig. 19), lactate of zinc (fig.
20).

LACTEALS. See Villi.
L.-EMAR'CtUS, Kroyer.— a genus of
Crustacea, of the order Siphonostoma, and
family Cecropidae.

L. muricatus. Found upon the sun-fish
(Orfhagoriscus mo/a). Length of female 1";
male much smaller.

BiBL. Baird, Brit. Entovios. p. 293.
LAFO'EA, Lamx: — A genus of Lafoeidae,
of the suborder Thecaphora (or Hydroida
with true calycles).

Char. Stem a simple creeping tubular
fibre, or erect and composed of many tubes
aggregated together, rooted bv a filiform

■2g 2

LAFOEID.E.

[ 4.52 ]

LAOMEDEA.

stolon ; hydrothecae tubular, sessile, or with
a short pedicel ; without an operculum ;
polypites cylindiical, with a conical pro-
boscis. There are five British species.
Blbl. llincks, Brit. Zmpli. p. 198.

LAFOE'ID.E.— A suborder of Hydi-oida.
See Lafoi^a.

LAGE'NA, Walker & Jacob.— A uni-
locular (rarely bilocular) In^aline Foramini-
fer, of the Nodosarine g-roup, generally flask-
shaped. The shell may be subglobular,
oval, oblong, or fusiform ; round, com-
pressed, or angular in section ; vaiiously
ornamented with ribs, network, tubercles,
and spines ; open at one or both ends, with
or without a neck, and often with the tube
turned inwards (Entosolenian). Recent
and fossil all over the world. Layena Icecis
(PL 23. f. 22) is a typical and very common
form. L. {Entosolenia) f/Iobosa (f. 2.3), with
the neck-tube introverted, is another very
common variety. L. striata (f. 24) is an
elongato-apiculate variety, delicately costu-
late. L. semistriata (f. 25) is L. globosa
with short basal ribs. L. sqiiamo-fa (f -IQ)
was so called because the early microscopes
showed the pitted reticulation as raised
scales. L. scaJariformis (f. 27) has a bold
hexagonal mesh ornament. The last is
recent, and the others are both fossil and
recent.

BiBL. Carpenter, Introcl. 156 ; Parker &
Jones, Phil. Tr. civ. 345; P., J. & Brady,
Mon. Cracj Foram. 28.

LAGENEL'LA, Ehr.— A genus of Infu-
soria, fam. Cryptomouadina.

L. euchlora (PI. 31. figs. 35 & 36) has a
carapace with a beak or neck like that of a
bottle, and a red eye-spot; freshwater;
lenirth 1-1150"; probabty an Alga-spore.

BiBL. Ehr. Lif. 45; l)uj. Inf. 3.33.

LAGENIP'ORA, Hincks.— A genus of
Cheilostomatous Polyzoa, fam. Porinidie.

i. socialis, on shells of the scallop [Pecten
ma.rimus) ; Hastings. (Hincks, Pulyz. 235.)

LAGENGE'CA, Kt.— A genus of Fla-
gellate Infusoria.

Char. Solitary, with a collar, in a protec-
tive sheath.

L. cuspidata (PI. 53. fig. 21), amber-
coloured ; pond water. (Kent, Inf. 359. )

LAGE'NOPHKYS, Stein.— A genus of
Vorticellina (Infusoria).

Char. Capsides not stalked, attached by
the side to other bodies ; body suspended
from the narrow orifice. L. vayinicula, on
the tail of Cydopsine ; 2 other species on
Gammarus. (Stein, Infus. 1854.)

mifi. Ph. Jn. 1858.

LAGY'NIS, Schultze, = £'M/7??/^j7<a pt.
LAGY'NUS, Quenn. — A genus of Holo-
trichous Infusoria. Free, flask-shaped, with
an oral cu-cle of longer cilia ; neck ringed.
L. eleyans, freshwater. (Kent, Inf. 520.)

LAMES'A'RLi, Lamx. — A genus of La-
mjuariaceee (Fucoid Algse), with large, flat,
stipitate fronds, several species of which are
common on rocky shores, attached to rocks
and stones. L. saccluirina has a riband-
shaped frond, growing from 2 to 12 feet
long. L. cliyitata has a broad frond, 1 to
5 feet long, cut into a variable number of
segments. The internal structure presents
three layers, the outermost forming a kind
of epidermis. The sporanyes (spores of
authors) contain ciliated zoospores which
reproduce the plant. They are little elon-
gated sacs, nestling between epidermal cells
of peculiar structure, standing perpendicu-
larly upon the central stibstance of the
frond. In L. saccharina the presence of
the sporanges is denoted by a longitudinal
brown mark in the centre of the frund ; in
L. diyitata they occur in flat patches on the
extremities of the digitations. The zoo-
spores are little olive-coloui-ed bodies, with
an anterior and posterior cilium. Thuret
has seen them germinate.

BiBL. Harvey, Mar. Aly. 29, pi. 4; Phyc.
Br. pi. 192, 22.3, 241 ; Greville, Aly. Brit.
t. 5 ; Thuret, Ann. Sc. Nat. 2 ser. xiv. 240,
pi. 30. figs. 1-4 ; Henfrev-Masters, Bot.

LAMINARLi'CE.E.— A family of Fu-
coidese. Olive-coloured inarticulate sea-
weeds, whose sporanges are superficial,
either forming indefinite cloud-like patches,
or covering the whole sm-face of the frond.
Brit, genera :
* Frond stalked, the stalk ending in an

expanded leaf-like portion.

Alai-ia. Leaf membranous, with a carti-
laginous midrib.

Laminaria. Leaf simple or cleft, without
a midrib.
** Frond simple, leafless.

Chorda. Frond cylindrical, hollow, with
transverse partitions.

LAMINGSIOP'TES, Megn.— A genus of
Acarina, allied to Sarcoptes.

L. yallinarum occurs in the subcutaneous
tissueof the (?a^//««'(Megniu, Pf/r^.v. 151,fig.).

LAOMEDE'A, Lamx.— A g.nus of Hy-
droid Zoophytes, family Campauulariidse."

LAOPIIOXTE.

[ 453 ] LATICIFEROUS TISSUE.

CJiar. Polypidom rooted, erect, jointed ;
the joint>i rinued and incrassate; cells alter-
nate, canipanulate, on short pednncles ;
vesicles axillary; embrj'os medusiforni.

Six British species : dichatoma (ovicell,
PI. '-V^. fig. 4 c), geniculata, f/elafinosa, ob/iqua,
F/cminf/ii, and htcerata. Found upon marine
Alga?, stones, kc, between tide-marks.

BiBL. Johnston, Br. Zooph. 101 ; Gosse,
Mar. Zool. ii. :24 ; Hincks, Br. Zooph.

LAOPHON'TE, Philippi.— A genus of
Copepodous Entomostraca. Eight species, in
dredgings. (Brady, Copep., Bay Soe. ii. 70.)

LAR, Gosse. — A geuus of Hydroid Zoo-
phytes.

Char. Bodies fusiform, sessile, with two
tentacula springing from the base of a bilo-
bate proboscis, developed on a creeping and
anastomosing stolon.

Lar saheUarum. The polypites bear a
close resemblance to the human figure.

BiBL. Gosse, Linn. Tr. xxii. 113, tab. xx. ;
Hincks, Br. Zooph. 36.

LAREL'LA, Ehr. — A genus of Rotifera,
fam. Brachionea.

Char. Body with equal setre and three
long fine hairs on each side of mouth ; two
frontal eyes ; length 1-190 to 1-280".

BiBL. 'Piitchard, Infns. 712.

LARVx-E. — In animals which pass
throug-h certain marked stages of develop-
ment, or undergo metamorphosis, as it is
called, the condition in the first of these
stages is called the larval state, and the
animal itself is called a larva.

The aquatic larvae of several insects are
well-known microscopic favourites on ac-
count of their transparence, which allows
the action of the dorsal vessels, with the
circulation of the nutritive liquid, to be
seen, and their curious respiratory organs.
A few of the more common aquatic larvse
and their parts are represented in PI. 35.
figs. 1, 14-17, 19-22, 29 ; these are noticed
more in detail imder their respective
heads.

The aquatic larvae of some Amphibia are
admirable objects for exhibiting the circu-
lation of the blood, the deAelopment of
tissues, &c.. as those of the frog (tadpoles)
and of the Triton.

LASIOB'OTRYS,Ktz.— A genus of Peri-
sporacei (Ascomycetous Fungi).

L. Lonicerce grows on the living leaves
and stems of various kinds of Honeysuckle,
forming little heaps seated on a tuft of ra-
diating filaments. The so-called peridioles
appear to be sclerotioid bodies, the superfi-

cial cells of which are converted into true
perithecia, becoming free on the surface :
these contain numerous asci when mature;
but the spores have not been observed.

BiBL. Berk. Br. Fl. ii. pt. 2. 324 ; Ann.
N. H. 2 ser. ix. 386, pi. 12. fig. 44 ; Fries,
Sum. Veg. 406 ; Greville, Sc. Crypt. Fl. pi.
191.

LASTRiEA, Presl.— A genus of Aspi-
diese (Polypodiaceous Ferns), now consoli-
dated with Nephrodium.

LATEX.— The name applied to the pe-
culiar juices, becoming milky when ex-
posed to air, contained in the * milk-vessels,'
or laticiferous canals of plants, especially
abundant in Euphorbiacese, Papaveraceae,
Cichoracese, &c. It appears to consist of a
watery fluid, with albumen in solution, in
which float globules of caoutchouc, or analo-
gous gum-resinous matter, of variable size,
occasionally mixed with starch-granules of
peculiar forms, as in Euphorbia (PI. 48.
fig. 23). According to Sachs andHanstein
it is a fluid which contains matters of a
directly nutritive character and others which
are excrementitious in their nature. Trecul,
on the other hand, appears to consider that
the latex is the residue of the sap after
elaboration by the cells. See Laticiferous

TISSUE.

BiBL. Schultz, Vaisseanx latici feres d.
Plantes, 1841 ; Mohl, Bot. Zeit. 1843 ; Ann.
N. H. xiii. 441.

LATHONU'RA, Lilljeborg.— A genus of
Cladocerous Entomostraca.

CJiar. Carapace obovate, not produced,
ventral margin furnished with peculiar
flattened spear-shaped plates attached to
the edge. I Irish species.

BiBL. Norman & Brady, Monogr., Nat.
Hist. Tr. Northumb.

LATHR^A.— A genus of Orobancha-
ceous Flowering Plants. L. squamaria, a
remarkable plant, found here and there in
beech-woods in England, has been the sub-
ject of much research as regards embiyo-
logy, by Schacht and others. See Ovule.

LATICIFEROUS TISSUE, ducts, ca-
nals, or VESSELS. — These names are applied
to the tubular and often ramified canals in
which the milky juice or latex of many
plants is contained (tigs. 388, 389). The na-
ture, or rather the origin, of these canals is
still a matter of dispute. The ducts present
themselves in various forms, especially in
the rind and pith of the Apocynacese,
Asclepiadacefe, Moraceae, Urtieaceae, Papa-
veraceae, Cucurbitace8e,Euphorbiaceae,Aroi-

LATICIFEROUS TISSUE.

[ 454 ]

LAURENCIA.

dese, &c. Simple unbrauclied milk-vessels
occur in tlae pith of the elder.

Schacht regards them all as liber-cells.
They have also been considered intercel-
lular passages, originally devoid of a proper
coat, but subsequently acquiring one of vari-
able thickness, derived apparently from the
secretion which they contain ; yet the pre-
sence of transverse partitions would invalidate

Fig. 388.

Fig. 389.

Fig. 388. Laticiferous canals from tlie root of Dan-
delion. Magn. 100 diams.

Fig. 389. Laticiferous tissue extracted from Chelido-
niutn majus, Magn. 100 diams.

this view. Unger, however, imagines that,
while some are formed in this way, they are
mistly developed out of confluent rows of
cells, like the dotted ducts ; and Trecul is
of opinion that they are ordinarily formed
in this way. Dippel considers that they
replace the clathrate cells of other plants.

Canals bounded by a defined coat of cel-
lular tissue, forming intercellular canals or
ducts of very definite cliaracter, occur in the
ConlferK, tlie Guttiferae, Auacardiacese, &c.
These will be spoken of under Secreting
Organs of Plants.

Canals containing a milky juice occur in
some of the Fungi, as in the fleshy sub-
stance of some Agarics, Zactarius, Sec.

It was declared some years ago by Schultz
that a regular circulation of tlie latex takes
place through the ramified laticiferous ducts.
This was chiefly supported on observations
of movements of the latex which may be
made on tolerably transparent parts of
living plants containing these ducts. By

bringing the uninjured sepal of Convolvulus
or a leaf of Chelidonhon under the micro-
scope (placing it in oil is advantageous in
the latter case), the branched latex-ducts
may be made out, and a flowing movement
of the particles may be seen occasionally.
But this has been shown to depend upon a
disturbance of the equilibriimi by external
causes, such as pressure and heat, and may
be produced at will in any direction by
making an incision, towards which the juice
flows. Trecul thinks that the laticiferous
canals communicate freely with the pitted
ducts and other vascular elements, and take
a share in a kind of circulation, wherein
they play the part of venous reser\oirs ; but
his views do not appear to us well founded.

Bjbl. Schleiden, Prmcip. of Bot. 1849 ;
Unger, An. und Pliys. 184(3,54; Schacht,
Monat. Berlin Akad. 1856; Flora, 1857, 89;
Meyen, Secretionsorgane, 1837, 63 ; Trecul,
Ann. So. AW.4 ser. vii. 290; Hanstein, Milch-
saftgefdsse, 1864 ; Dippel, Milchs. 1865 ;
Vogel, Jahr. wiss. Bot. v. 31 ; Sachs, Bot.
88

LAURENCIA, Lamx.— A genus of Lau-
renciacefe (Florideous Algse), containing
several British species, mostly conimou, of
yellowish-green, purple, or pink colour, the
fronds pinnately braucbed, of solid paren-
chymatous structure. The ceramidia are

Fig. 390.

Laureucia dasyphylla.

Eamnli containing tetraspores.

Magnifled 50 diameters.

borne on the smaller branches, as are also
the antheridia ; the tetraspores are imbedded
in the ramuli (fig. 390). The ceramidia
contain tufts of pear-shaped spores; the

LAURENCIACE^E.

[ 455 ]

LEAVES.

tetraspores are tetralieclrally divided. The
autlieridia ave thus described (in L. tenuis-
sima) by Thuret : on the smaller branches,
similar to those which bear the ceramidia
on other indi\ iduals, occur grej-ish convo-
luted plates of cellular tissue, of irregular
form, bordered by a line of roundish cells,
containing generally a yellow liquid. Hya-
line cells containing antlierozoids are im-
planted vertically on these plates, clothing
both surfaces. The antheridium has a sort
of pedicel formed of an ovoid cell, which
also bears a dichotoraous hair, like those
common over the branches of this plant.
The autherozoids are elongated-ovoid, a
little constricted at one extremity, length
about 3-5000". Derbes and Solier have
obsei'ved them on L. pinnatijida and other
species.

BiBL. Plarvey, Mar. Ah/. 97, pi. 12 C ;
Phi/c. Brif. pi. 5o ; Grev. Ahj. Br. 108, pi.
14 ; Derbes and Solier, Ann. Sc. Kat. 3 ser.
xiv. 276, pi. 37 ; Thuret, ib. xvi. 65, pi. 7,
lb. ser. 4. iii. 19.

LAURENClA'CE.E.— A family of Flo-
rideae. Rose-red or purple sea-weeds with
a cylindrical or compres.-ed, rarely flat, li-
neal", narrow, areolated, inarticulate, or con-
stricted and chambered, branching frond
composed of polygonal cells. Fructification :
1, conceptacles {ceramidia) external, ovate,
furnished with a terminal pore, and con-
taining a tuft of pear-shaped spores ; 2, te-
trasporcs immersed in the branches and
ramidi, scattered without order through the
surface cells ; 3, anfkeridia.

British genera :

Bonnemaisonia. Frond solid, filiform,
rose-red, much branched; branchesmargined
with subulate distichous cilia.

Laiirencia. Frond solid, cylindrical or
flattened, purplish or yellowish, pinnatifid,
ramuli blunt.

Chrysimenia. Frond hoUow, filled with
mucus, neither constricted nor chambered.

Chylocladia. Brancheshollow, with mucus,
constricted at intervals.

LEA'IA, Jones. — A fossil Entomostracan
Bivalve, of unknown alliance, probably a
Phyllopod. Valves oblong; marked with
two obliquely transverse, divergent ridges,
concentric lines of growth, and intermediate
reticulation. Known in the Coal-measures
of Britain and America.

BiBL. Jones, i^oss. Estlierite, 1862, 115 j
Geol. May. vii. 219.

LEANGIUM, Lk. See Dideema.
LEATHE'SIA, Gr^iy.— A genus of Mvrio-

nemacone (Fucoid Algoe), consisting of glo-
bose or lobulated lleshyor horny structures,
growing upon rocks, either solid, or, by the
solution of the internal filamentous sub-
stance, ultimately hollow. Tlie fronds are
composed of masses of dichotomous fila-
ments radiating from a point ; in the olive-
coloured tufted species cohering laterally,
and forming the soft, fine coat of the lobes.
The sporanges are simple oval sacs attached
to the ends of branches of the radiating
filaments, between which they nestle ; or
multilocular, consisting of short septate fila-
ments occurring in similar situations, which
are said by Thuret to be more common ; and
the two kinds have not been met with
together.

BiBL. Harvey, Mar. Alg. 48, pi. 10 C ;
Enql. Bot. pi. 1596 ; Thuret, Ann. Sc. Nat.
3 ser. xiv. 237, pi, 26. figs. 5-12.

LEAVES. — The microscopic structure of
leaves presents a wonderful variety of con-
ditions, from the most simple up to very
complex. Instances of the former are seen
in the Mosses, JuNGERMANNiE^,aud other
Flo werless plants, where merely a simple cel-
lular plate exists. In the simpler leaves of

Fig. 391.

Vertical section pf a leaf of a Melon.

E. S, superior epidermis ; P. S, subjacent close paren-
chyma; J/, infra-stomatal air-space; L, intercellular
space; F. v, flbro-vascular bundle (rib or vein ) ; P. i,
inferior lax parenchyma; S. i, inferior epidermis; P,
hairs ; ST, stoma.

Magnified 100 diameters.

Ferns, such as Hymenophylltjm, we have
a cellular plate traversed by vascular ribs.
In Sphagnum (among the Mosses) the sim-
ple leaves have cells containing a spiral

LECANOEA.

[ 45G ]

LEIBLEINIA.

fibre. In the more complete forms "we dis-
tinguisli an epidermis, above and below,
often difleriug in character on the two faces
(see Epideemis and Stomata), together
with the diachyma or intervening celhilar
mass, which varies in its characters in dif-
ferent plants, and is traversed by the tibro-
vascular ribs or veins. The epidermis ex-
hibits Gl.\xi)S, Hairs, &c., in diiferent con-
ditions and forms, which cannot be enume-
rated again here, many of the most inter-
esting forms being mentioned under the
above heads. For observing the structure
of leaves, when consisting of more than a
simple cellular plate, horizontal and vertical
sections are required. The latter are easily
made with a sharp razor in thick and firm
leaves ; but with delicate kinds it is neces-
sary to split a soft cork, to place the leaf
carefully between the pieces, and then to
slice both together, placing the fragments
in water and picking out the pieces of the
leaf with a needle. Many small simple
leaves make good objects by drying, soaking
in turpentine, and mounting in balsam ; the
same may be done with petals, sepals, kc.
Tlie leaves of many water-plants, such as of
Tallisneria, Anacharis, CeratopJnfUum, Hot-
tonia, (fcc, are very favourable for the ob-
servation of the rotation of the cell-sap (see
Rotation). They are of very simple cel-
lular structure, having no epidermis, sto-
mata, or fibro-vascular ribs.

Leaves also afford a large field for inter-
esting study to the microscopist, in the
examination of the colouring-matters and
secretions in the cells, especially during the
autumnal changes, of the 'development, &c.,
and moreover in the investigation of the
parasitic Fungi which so frequently attack
them both in the living and the decaying
state.

LECAN'ORA, Ach.— A genus of Le-
canorei (Lichenaceous Lichens), the species
growing chiefly on rocks, stones, and earth.
Thalluscrustaceous, granular,rarely radiate ;
apothecia lecanorine ; paraphyses distinct ;
thecsB either eight-spored or polysporous ;
spores simple.

BiBL. Hook. Br. Flor. ii. pt. 1 ; Engl. Bot.
pi. 940; Leighton, Lkh. 1879.

LECID'EA, Ach. — A genus of Lecideinei
(Lichenaceous Lichens), containing nume-
rous British species. Tlie apothecia have a
border of the same colour as the disk.
Growing chiefly on rocks, sometimes on
bark. L. geor/rapliica, growing on subalpine
recks, is a rejnai'kable species.

BiBL. Hook. Br. FI. ii. pt. 1. 177 ; Engl.
Bot. pi. 245, &c. ; Leighton, Lich. 240.

LECIDEI'NEL— A tribe of Lichenacei,
containing the genera LecideayOdontotrema,
and Schizoxylon.

BiBL. Leighton, Lich. El. 240.

LECYTH'EA, L^v. See Uredinet.

LEECH.^Two species of the genus Hi-
rudo, which belongs to the class Aunulata,
are used for medicinal purposes, viz. //. me-
diemalis, in which the ventral surface is
greenish, with black spots ; and H. offici-
nalis, in which these spots are absent.

The structure of the mouth of the species
of Hirudo is curious. The mouth is trian-
gular (PI. 22. fig. 25), and placed in the
middle of the anterior sucker. Each of its
three sides is furnished with a semicircular
jaw, of cartilaginous consistence (fig. 26,
side view ; fig. 27, view from above), upon
the convex margin of which are placed a
large number of partly calcareous teeth
(fig. 26 b) arranged in a row. The teeth
(fig. 28, a side view, h view from above)
are flattened, somewhat triangular, and ex-
cavated at the base, so as to exhibit two
short prongs (d). They are placed trans-
versely upon the jaws, which are moved by
powerful muscles, and thus produce the
well-known wounds. And this cross di-
rection of the teeth is probably the cause of
the troublesome bleeding accompanying the
bite of a leech, in consequence of the
amount of laceration necessarily connected
with it.

The species of Hirudo have ten minute
eyes, arranged in the form of a horseshoe
at the upper part of the anterior sucker.

The ova of leeches are deposited in a kind
of cocoon, composed of triangular fibres,
branched and interwoven so as to somewhat
resemble a sponge, as which one of them
was formerly described.

BiBL. Brightwell, Ann. N. H. 1842, ix.
11 ; Brandt and Ratzeburg, Mcdiz. Zool. ii. ;
Johnson, Medicinal Beech ; Moquin-Tandon,
Monog. Hirndinees ; Savigny, Ee.tcript. de
rEf/gpte,x\i. ; Audouinand Milne-Edwards,
Ann. jSc. Nat. 182.3, 27-oO ; R. Jones, Otdl.
of An. Kingdom ; Gervais and Van Bencden,
Zool. Med. ; Schultze, Zeits. iciss. Zool. xii.
18G2; Leuckart, Memch. Parasit. ;Gratiolet,
An7i. Sci. Ned. iv. 17 ; Lankester, Qu. 31.
Jn. 1880, XX. .307.

LEIBLEl'NIA, Endl.— A genus of ma-
rine plants, placed among the i>tocarpaceae
by Eudlicher, and among Oscillatoriacese
(Confervoid Algae) by Kiitzing, who includes

LEIOSOMA.

[ 457 ]

LEMON.

under it many of the species of Cahthrix of
other authors. Endlicher cites only C. con-
fvrvicola, Ag., and another not British.

It is a minute, glaucous, tufted plant,
formed of short, rigid, erect, subulate iila-
ments, and is common, epiphytic on marine
filamentous Alg.ie.

BiBL. ]<:ndl. Gen. Plant. Supp. iii. No. 69 ;
Kiitz. Sp. Alg. 276; Harvey, Phyc. Br.
223, pi. 2(3 C.

LEIOSO'MA, Koch.— A genus of Ori-
batea ; has the cephalothorax with plates,
the tarsi with three heterodactyl claws ;
two species. (Murray, Ec. Entom. 216, tig.)

LEJEUX'IA, Libert.— A geiius of Juii-
germanniepe (Ilepaticte), containing several
rare British species, found in suhalpine dis-
tricts, viz. L. serpi/Uifolia, hamatifolia, mi-
nut issima, and cahiptnfuUa. The last is one
of the smallest of the British Jungerman-
nicae, and is remarkable for the peculiar
form of its leaves, which resemble the ca-
lyptra of a moss (figs. 392, 393).

Fig. 392.

Fig. 393.

Lejennia ealyptrifolia.

Fig. 392. Stem with calyptriform leaves, an immatnre
plant (on the right), and a burst sporange.
Magn. .5 diams.

Fig. 393. A leaf of ditto. Magn. 25 diams.

BiBL. Hook. Br. Jung. pis. 42, 43, 51,
62 ; Br. Fl. ii. pt. 1, 127.

LEMANI'E.E.— A family ofConfervoi-
dese. Olive-coloured freshwater Algae, fila-
mentous, inarticulate, of cartilagineo-coria-
ceous substance, and compound cellular
texture. The /"ro??f7s branched, hollow, bear-
ing within at irregular distances whorls of
wart-like bodies consisting of tufted, sim-
ple or branched, necklace-shaped filaments
(fig. 394), arising from the inner wall of the
tubular frond, and finally breaking up into
elliptical spores. British genus :

Lemnnin. Character the same as of the
family. Two species have been found in

Britain, L. toruhsa, Ag., and L.fluviatilis.
They always grow in clear runniug streams.
Thwaites has made some interesting obser-
vations on the development of these plants.

Fig. 394.

A genus of

Lemania torulosa.

Section of frond, showing the tufts of fertile filaments.

Magn. 50 diams.

See CoMPSOGON.

BiBL. Hassall, Alg. 68, pi. 7 ; Kiitz. Phyc.
gen. 271 ; Thwaites, Ann. N. H. 2 ser. i.
460 ; Wartmann, A7iat. d. Lemania., 1854 ;
liabenhorst, Alg. iii. 410 ; Sirodot, Lema-
neac. 1875 (23 pis.).

LEMBA'DIUM, Perty.
Holotrichous Infusoria.

Char. Body oval, flat, with a broad deep
buccal fossa, having an undulate membriine
on one side.

L. bullinum ; marsh water.

BiBL. Claparede et Lachm. Inf. 251 ;
Kent, Inf. 536.

LEM'BUS, Cohn.— A genus of Holo-
trichous Infusoria. Free, elongate, mouth
ventral; a triangular ventral undulating
membrane. Four species ; marine. (Kent,
Inf. 547.)

LEM'NA, L. — Duckweed. A genus of
aquatic Monocotjdedonous plants, remark-
able for their simplicity of structure, the ve-
getative system being replaced by a minute
leaf -like floating stem, with dependent root-
lets, furnished with a well-developed sheath
(pileorhiza) at the end. The lobes of the
stem bear two monoecious imperfect flowers,
and also propagate by bulbils formed in
the slits in the side of the lobes ; the
young bidbils formed in autumn sink when
the parent dies,, and rise again in spring.
Spiral vessels occur abundantly in L.
pohjrhiza ; they are sparingly present in
the rest.

BiBL. Hook, and Arnott, Brit. Flor. ;
Schleiden, Bot. 229; Weddell {Wolffia),
Ann. Sc. Nat. 3 ser. 12, 155.

LEMON, EssEXTiAi. oil or. — This is
sometimes used in the microscopic examina-
tion of pollen and other structures, which
are placed in it to render them more trans-

LExXTICELS.

[ 458 ]

LEPISMA.

parent, being less disagreeable and less vo-
latile than oil of turpentine. Glycerine may
often be substituted.

LENTICELS.— Structures found upon
the surface of young stems, especially of
most of the Dicotyledonous shrubs and
trees. They first appear on the yearling
shoot as little specks, of a different colour
from the rest of the epidermis. Towards
the winter, or in early spring, the epidermis
splits transversely over the lenticels, which
become then slightly projecting papillae,
frequently divided into lips, as it were, by a
median furrow. The surface of the papilla
is now brown ; and it is of corky character
for some little distance inwards. As the
branch grows, the lenticels become drawn
out laterally, so as to appear like cross
strife. They are subsequently lost sight of
by the bark splitting through them, as in
the apple or beech, or by the bark peeling
off" (plane).

Microscopic examination of sections shows
that they are mere hypertrophal produc-
tions from the epiphloeum, or suberous hnjer
of the BARK, and have no connexion with
the liber or cambium. DeCandolle ima-
gined they were root-buds, where adventi-
tious roots might arise under favourable
circumstances ; but this was an error. Du
Petit Thouars thought they were breathing-
pores, replacing the stomata of the epider-
mis; but they are not pores; and many trees,
such as the Conifers, Roses, Euonymus eu-
ropceus, &c., have none.

BiBL. DeCand. Ann. Sc. Nat. 1826, vii,
5; Mohl, Vennischt. Schrift. 229, 2.33 ; Meyer,
Linncea, vii. 447; Unger, Flora, 1836, ii.
677 ; St. Pierre, Compt. Rend. 1855 ; Ann.
N. H. 2 ser. xvi. 273.

LEPADEL'LA, Bory.— A genus of Ro-
tatoria, of the family Euchlanidota.

Char. Eyes absent ; foot forked.

Three species.

L. emarffinata (PI. 43. fig. 43). Carapace
depressed, oval, anterior portion broad,
emarginate at each end. Freshwater}
length of carapace 1-570".

Teeth of L. ovalis, PI. 43. fig. 44.

BiBL. Ehr. Infi(s. p. 457.

LEPEOPHTHI'RUS,Nordm.— A genus
of Crustacea, of the order Siphonostoma,
and family Caligidoe.

C/iar. Fourth pair of legs slender, not
branched, formed for walking ; thorax with
only two distinct joints ; frontal plates
destitute of .sucking-disks on the under sur-
face. Six British species, found upon

various marine fishes, as the salmon, mac-
kerel, sole, brUl, turbot, &c.

L. pedoraUs (PI. 19. fig. 23).

BiBL. Baird, Brit. Entvmost. p. 273.

LEPERDITIA, Rouault.— An extinct
bivalve Entomostracau, probably Ostra-
codous ; bean-shaped ; smooth ; straight
on the dorsal, convex on the ventral
margin ; smaUer in front than behind ;
right valve overlapping the left along
the ventral edge ; each valve bearing a
pitted and radiate muscle-spot and an
oculai' tubercle. The dorsal region of the
left valve is swollen in some species.
Fossil only.

30 Silurian species, 6 Devonian, and -14
Carboniferous, with many varieties.

BiBL. Jones, Ann. N. H. 2 ser. xvii. 81 ;
5 ser. ix. 168 ; M. Mic. Jn. iv. 184.

LEPIDOCYR'TUS, Latr.— A genus of
Thysanura.

L. curvicollis is one of the insects which
yield the so-called Podura-&cales. The
first segment of the thorax is as long as the
two next, and projects so as to cover the
neck and part of the head. It is found under
stones or old wood. See Poduba.

LEPIDOPTERA.— An order of Insects,
consisting of butterflies and moths.

Lepidopterous insects present several
points of interest to the microscopic ob-
server ; among these may be mentioned
especially the proboscis or ANTLiA,the hook
connecting the wings (Insects, p. 432), the
wings themselves, and the beautiful scales
covering them (Scales of Insects, Test-
objects). Their larvje or caterpillars are
favourable subjects for the examination of
the internal structure — the trachere with
their spiracles, the fatty body, the alimen-
tary canal, the spinning organs, the curious
legs, &c.

LEPISMA, Linn.— A genus of Thysa-
nurous Insects, family Lepismenae.

Char. Body elongated, flattened; antennae
setaceous, with numerous very short joints ;
palpi four, lono- ; abdomen terminated by
three long filaments jointed near their
ends.

L. saccharina (PI. 35. fig. 18). Body
silveiy-grey, not spotted, covered with
scales ; caudal filaments speckled with
reddish brown ; antennae about two-thirds
the length of the body.

This active little insect, which runs but
does not jump, is found (in the country)
upon the slielves of cupboards where sweets
and other eatables are kept, in window-

LEPRALIA.

[ 459 ]

LEPTOTHRIX.

cracks, &c. Its habits are nocturnal. Its
beautiful silvery scales are used as Tkst-
OBJECTS (PI. 1. Hg. 6).

There are many other species, the scales
of which probably exhibit the same struc-
tiu'e.

BiBL. Gervais, Walckenaer's Apteres, iii.
p. 450 ; Lubbock, Liim. Trans.

LEPRA'LIA, Jolinst.— A genus of Chei-
lostomatous Polyzoa, family Membranipo-
ridffi (Escharidfe, Hincks).

C/iar. Polypidom adnate, crustaceous,
formed of a layer of juxtaposed urceolate
cells, closed iu front, and spreading cir-
cularly.

The very numerous species form white,
yellow, or reddish crusts upon rocks, shells,
and sea-weeds. Avicularia and vibracula
preseut in some, but absent in others. Mouth
of cells sometimes with spiues.

L. variolosa (PI. 41. fig. 17). Cells
oblong, depressed, roughish, interstices
punctured ; orifice semioval or roundish,
margin plain. On stones and shells, com-
mon : varieties occur with the lower lip
notched, or with a tooth.

L. nnicomis. Cells ovate, scaly, with a
short obtuse process or knob above the ori-
fice, wliich is roundish, with a distinct
notch in the upper margin ; common.

BiBL. Johnston, Br. Zooph. 300 ; Busk,
Mar. Polyz. ; Hincks, Pohjz. 297.

LEPTbCLI^X'M, M.-Edw.— A genus of
Tunicate Mollusca, of the family Botryllidte.

Distinguished by the thin, sessile, in-
crusting mass of variable form, the nume-
rous systems, the six-rayed branchial ori-
fice, and the anal orifices opening into a
common more or less branched cloaca.

Six British species: mactdosum,asperum,
aureum,geIatinosum, Listerianum, and punc-
tatum, found upon the roots of Laminaria
and other marine algae ; the two former
common.

BiBL. Forbes and Hanley, Br. Mollusca,
i. 16; Gosse, Mar. Zool. ii. 32 ; M.-Edwards,
Mem. sur les Ascicl. comp.

LEPTOC YSTINE'MA, Archer, = Go-
NATOZYGON, De Barv, 1856.

LEPTODIS'CUS,"Hertwig.— A genus of
marine Flagellate Infusoria.

L. medusoides, diam. \" ; Messina. (Ivent,
Itifus. 400.)

"LEPTOGIDllIM, Nyl.— A genus of
CoUemacei (Byssaceous Lichens). L. den-
driscwn, on mossy trees on high moimtains.
(Leighton, Lich. Ft. 13.)

LEPTO'GIUM.— A genus of CoUema-

ceous Lichens. Thallus with a distinct
cortical layer, granida ; gonima nionili-
forni ; apothecia lecanoriue ; spores eight,
multilocular, rarely simple. Species nume-
rous. On mossy trunks, walls.

BiBL. Leighton, Lich. Flor. 25,

LEPTO'MOXAS, Kt.— A genus of Fla-
gellate Infusoria. Free, narrowly fusiform,
fiageUum single.

L. Biltschlii, in the intestine of Trilohus
gracilis. (Kent, Inf. 243.)

LEPTOS'CYPliUS, AUman.— A genua
of Hydroid Zoophytes.

Char. Capsules ovato-conic; polj^ea
cylindrical, proboscis conical ; reproduction
by free medusiform bodies.

L. tenuis, on Laminaria ; Stromness.

BiBL. AUman, A7in. N. H. 1864 ; Hincks,
Br. Hifd. Zooph. p. 196.

LEPTOSTPtO'MA, Fr.— A genus of
Sphaeronemei(StylosporousFungi), probably
consisting only of the younger stylosporous
states of species of Hysterium or Phaci-
Diusi. Several species are recoi-ded as
British, some common, occurring on the
stems and leaves of sedges, rushes, Pteris,
&c., forming small round flat spots, from
which the upper part of the perithecium
splits off, leaving a little margined scar, in
which are seated the stvlospores.

BiBL. Berk. Br. i^/. 'ii.pt. 2. 297 ; Ann.
N. H. i. 257, vi. 365 ; Tulasne, Ann. N.
II. 2 ser. viii. 114.

LEPTOTHRICH'E.E.— A subfamily of
the Oscillatoriaceae. Filaments very fine,
adnate, sheathed, indistinctly articidate ;
movement slow ; solitary or fasciculate ;
for the most part in broad and diffused
layers.

BiBL. Rabenhorst, Ft. Alg. ii. 8 & 73.

LEPTOTHRIX, Kutz.— A supposed ge-
nus of Oscillatoriaceae. Found on damp
stones, among wet plants, and in foul water ;
very probably consisting of the mycelial
filaments of mildew Fungi.

The filaments are very slender, simple,
continuous or obscurely jointed.

L. ochracea, K. (Oscillatoria ochracea,
Grev.) is an obscure production, forming
yellowish-brown flocculent masses, common
in boggy pools.

L. buccalis and L. insectoruin, Ch. Robin,
probably belong to some Fungus.

BiBL. Kiitz. Sp. Alg. 262 ; Tab. Phi/c. i.
pi. 61. fig. 1 ; Roliin, Veget. Parasit.
2nd ed. 345, 355 ; Mettenheimer, Mus.
Senckenb. 1857, 139 j Moggridge, Jn. 31. S.
1868.

LEPTOTIIYPtlUM.

[ 460 ]

LEUCOPHRYS.

LEPTOTHYTJUM, Kiitz.— A genus of
Spliperonemei (Stylosporous Fungi).

L. juf/Iandis, Lib., L, friujarife, and
L. ribis have been found in Britain ; they
are probably stylosporous forms of Asco-
mycetes.

BiBL. Fries, Siwi. F<?<7. 371, 423; Berke-
ley, Ann. N. H. 2 ser. v. 371 ; Tulasue,
Ann. Sc. JVdt. 4 ser. v. 115.

LEPTOTRICHA'CE.E.— A family of
operculate Acrocarpous Mosses, brauching
by innovations, or with the fertile summits
several times divided. Leaves lanceolate
or awl-shaped, often canaliculate-concave,
with a nerve, mostly flattened or terete ;
cells pvosenchymatous, often mingled with
parenchymatous, lax or firmish, empty, not
unfrequently thickened at the apex, then
square. Capsule ovate or cylindrical, some-
times naked, sometimes erect, often stru-
mulose at the base ; operculum conical or
subulate. Differing from Dicranacese in the
absence of alar cells to the leaves. Brit,
gen. :

Auf/stramm, Brachyodus, Can^njloste-
lium, Leptotrichuin, Seliqeria.

LEPTO'TPJCHUM; Hampe.— a genus
of Acrocarpous operculate Mosses, including
certain Didt/modGnta and Trichostoma of
other authors.

LEPTOTRICPIUM, Corda.— A genus of
Sepedouei (Hyphomycetous Fungi) ; not
British.

LEPTUS, Lam. See Trombidium.

L. autumnalis (^Trombidium autumnale),
the harvest-bug.

LERN^EA. — A genus of Poecilopoda
(Crustacea).

L. branchiaJis, on the gills of the cod.
(Baird, Br. Entom. 344.)

LERNEOXE'MA, Edwards.— A genus
of Siphonostoma (Crustacea).

Char. Body long, slender, nan-owed an-
teriorly in the form of a neck, terminated
by a swollen head, with two or three
simple, CTU'ved, horn-like appendages ; abdo-
men of inconsiderable length, simple ; ovi-
ferous tubes long and slender.

Two British species : L. sprafta (PI. 19.
fig. 24), length 2 inches ; and L. encrasicholi.
Both found upon the sprat.

BiBL, Baird, Brit. Entomostraca, 339.

LESKEA, Iledw. — A genus of Mosses.
See Hypnum.

LEUCINE, or caseous oxide, is a normal
constituent of the lungs, spleen, pancreas,
the saHvary glands, &c., and is produced
during the putrefaction of albuminous and

gelatinous matters. L^sually accompanied
by tyrosine, it crystallizes in minute spheres,
which frequently imite and form radiating
clusters, which often present a yellow tinge
and a concentric lamination. It is soluble
in water, less so in alcohol. The alkaline
pancreatic juice transforms albumen into
leucine and tyi'osine. It also occurs in the
Crustacea, Arachnida, and Insecta.

BiBL. Frev, Hist. 49 ; Rindfleisch,
Path. Hist. 14 ; Voit, Kdll. 8,- Sieb. Zeitsch.
ii. 1868.

LEUCO'BRYUM, Hampe.— A genus of
Bryacese, Acrocarpous Mosses,but exhibiting
also lateral fruit-stalls. Capsule, lid, and
peristome as in Dicranuin ; but the leaves
whitish, spongy, and composed of two
layers of cellular tissue, the nerve indistinct.

L. (jlaucum. On moist heaths, woods,
&c.

BiBL. Wilson, Bryol. Br. 82.

LEU'COCYTES.— These are the colour-
less corpuscles of the blood, Ivmph, &c.

LEU'CODON, Schwajgr.-^A genus of
Pleurocarpous Mosses.

Chnr. Capsides oval, erect, pedicel short,
calyptra large ; outer teeth IG, bifid or
perforated, not hygroscopic : shoots simple ;
leaves plicato-stiiate, nerveless.

L. sciuroides, trunks of trees and walls,
frequent ; L. Lagitrns., rare. (AVilson, Brijol.
Br. 313.)

LEU'COPHRYS, Ehr.— A genus of the
family Bursarina (Ciliated Infusoria.)

Ch.ar. No sheath ; body truncated in front
obliquely ; buccal cirii surrounding tlie
truncation ; anus at the posterior extremity ;
no watch-glass organ ; no rows of cilia in
the interior of the biiccal fossa.

Ehrenberg describes eight species ; they
are found in salt and fresh water, both sweet
and putrescent.

L. patida (PI. 31. fig. 38, a dorsal, b ven-
tral surface). Body ovato-campanidate,
hyaline or white, turgid ; mouth large, pa-
tulous. Freshwater and marine. Length
1-288 to 1-90". The alimentary canal,
with the sacculi, according to Ehrenberg's
view, is represented in fig. 31 n.

L. spat h II In (Spathidium hyalimnn, D.)
(PI. 31. figs. 75, 70). Body lanceolate,
compressed, whitish, membranous, obliquely
truncated and dilated in front; freshwater.
Length 1-144". Dujardin denies the exist-
ence of the anterior row of cilia. A very
doubtful form.

PI. 31. fig. 37 represents L. striata, D.,
which is one of the Upalina.

LIBELLULID.'E.

[ 4G1 ]

LIBER.

BiBL. Ehrenb. Inf. 311 ; Duj. Inf. 453 ;
Stein, Inf. 184; Clap, et Lachm. Infus.
1808.

LIBELLULID.E.— A family of Insects,
of the order Neuroptera. It contains
several common but beautiful insects, some
of whicli are p,)pularly known as Dragon-
flies and horse-sting-ers, although they are
harmless. The great interest connected
with theui relates to the structure of the
larvoe and pupas, whicli live in water, and
are furnished with brauchite, either inter-
nal or external, situated at the end of the
body. Exteruil branchiae are seen in
Af/i-ion (PI. 35. fig. 17). They consist of
three membranous plates (PI. 35. fig. 2 f/),
traversed by innumerable tracheae. In
JEschna, Lihellula, and Calepteryx the
branchiae are internal and situated within
the rectum (PI. 35. fig. 20, rectum of
yEschna). In this last genus the brauchiie
are in the form of plates, which are nu-
merous, semicircular, longitudinal, imbri-
cated, and arranged alternately in six regu-
lar and symmetrical columns. The laminae
consist of a network of fine tracheae, com-
municating with those of the body and
situated beneath the mucous membrane.

The end of the abdomen is furnished with
five movable valvular pieces (PL 35. fig. 29),
three of which are larger than the others,
and the uppermost of which is notched at
the end. These pieces, by their contraction,
expel the water from the rectum ; it is
renewed ; and the expulsive force effects the
locomotion as well as the respiration of the
insect. The labium of ^schna also possesses
aremarkable structure, forming an elongated,
somewhat spatulate, mask-like appendage,
which completely closes the mouth when
unemployed (PI. 50. fig. 16). In the other
genera the sti-ucture is very similar. In
Libelhda six biserial rectal columns are also
present ; but there are no papillae on them ;
and the caudal appendage is pointed and
not notched (PI. 35. fig. 22). In Caleptenjx
the rectal brauchite are more simple, con-
sisting of three plates attached only by the
end, and resembling in structure the external
plates of Agrion \ the ocelli are distinct ;
and the external caudal aperture consists of
three channelled and keeled pieces. The
spiracles of these larvae and pupte are more
or less concealed in the interspace between
the proto- and mesothorax ; they are trans-
verse, bilabiate, and furnished with a mus-
culo-membranous valve.

Bjcbl. Dufour, Ann. Sc. Nat. 1852, syii.

65 ; Westwood, Introd, ; Packard, Amer.
Natur. v. 1871 ; Oustalet, Ann. Sc. Nat.
xii. ; Selys-Longchamps, vlf'j/i. Lihell.d' Eu-
rope ; Charpentier, Libell. Eur op. 48 pis.;
Lenderfeld, JVinr/s of, 1881.

LIBER (Phloeni).— The term liber-cells
or -fibres is applied to the very long pros-
enchymatous cells, occurring isolated or
in bundles at the outside of the cambium-
layer of Dicotyledons, and often in the pith
and the ribs of the leaves ; to the cells of
similar form and character occurring in the
outer part of the tibro-vascular bundles of
Monocotyledons, andinthebranchesof those
containing no spiral structures ; also to the
fibi'ous cells of the same kind found in the
husks of many fruits, as the cocoa-nut ; they
are constantly ringed with sieve-cells or
-tubes. No exact Une of demarcation can
be drawn between liber-cells and wood-ceUs,
since the shorter of th 3 former pass into the
latter. As a rule they are much thickened
by secondary deposits (PI. 47. fig. 27j ; but
these deposits are tougher than those of the
wood-cells; and while they have pores, these
are never bordered with a rim. Liber-cells
are not uufrequently found branched (Rhi-
zophoracese, Gnetmn) ; and some of the
branched forms are supposed to originate
by the confluence of originally distinct cells,
after the manner of milk-vessels.

The layers of thickening on the walls of
liber-cells frequently exhibit a spiral stria-
tion, especially after treatment with acids
(PI. 28. figs. 2, 3, 25). Mohl has pointed
out the peculiar characters of certain struc-
tures associated with liber in the bark of
Dicotyledons and in the vascular bundles
of Monocotyledons. These are the vasa
propria, and are described under Vascular
Bundles.

The importance of liber as a material for
textile fiibrics has been spoken of under Fi-
brous Structures, and examples cited ;
figures of various kinds of liber-fibre are
given in Plate 28.

In Dicotyledonous stems the fiber-fibres
are usually placed in large bundles opposite
the fibro-vascular bundles of the wood,
as in Urtica, Viscum, Clematis, Quercus,
&c. ; sometimes in smaU irregular groups,
as in Vinca and Linum ; in other cases they
stand in single rows, alternating with
parench^nna or vasa projyria (Cupressinece
and Ta.rinece), while in many plants they
are irregularly scattered, as in Bhizophora,
Cinchona, Nerium, &c. Isolated liber-cells
occur in the pith of young shoots, and may

LIBER.

[ 462 ]

LICHENOPOEA,

bo readily seen in the long woody radicles
developed from the seeds of the Rliizopho-
rese (PI. 48. fig. 31) ; and in the bark and
pericarp of Gnetum, isolated branched
liber-libres occur scattered throughout the
whole mass.

In many Dicotyledons the thick-walled
liber-cells are formed only in the first year,
the subsequent formation in this region
consisting of new layers of vasa propria
and parenchymatous cells {Betula alba
and Fagus sylvatica). In Viburnu^n Lan-
tana the thick-walled liber is entirely
wanting.

In the Monocotyledons they occur asso-
ciated with short wood-cells in the fibro-
Tascular bundles ; but they form alone the
fibrous bundles often intermixed with and
prolonged from the ends of these, occui-ring
especially in the outer part of the stem of
herbaceous Monocotyledons, such as Lihes
and Grasses, and in the fleshy cortical layer
of rhizomes, as in Sparganiwn, kc.

In both families they occur with the spiral
vessels and wood-cells in the ribs or veins
of leaves (as in Phormium tenax), bracts,
spathes of Palms, &c.

Liber-cells are generally drawn out very
gradually to a point at each end ; sometimes
they are very long ; Schleiden states he has
seen them 5" or 6". Sometimes they exhi-
bit expansions at particular points, as in
the Apocynaceae. The branched forms
in Rhizophorea?, Gnetum, &c. are usually
much shorter than the simple fibres, and
their form is often very irregular (PI. 48.
fig. 31). The diameter varies a great deal
in some plants ; and we should scarcely ven-
ture to say that the microscopic appearance
of a liber-fibre would suffice for the deter-
mii^ation of the material of any (vegetable)
textile fabric, beyond the distinction of
cotton (or vegetable hair) from linen or other
liber ; but reagents affect them differently.
The appearance presented by many kinds
of fibre under the microscope, in the state
in which they occur in commerce and after
treatment with acids, is shown in PI. 28.
figs. 2-7, 25 & 20. The figures are taken
from very characteristic exiim])l('S : but mnny
modifications occur in subordinate qiiaiitity.
Flax (Linnm tisitatissimvm) (fig. 2) has the
walls much thickened, with distinct pores ;
it exhibits a very oblique close striation after
boihug with nitric acid. Jute, the liber of
Corchorus capsnlaris, has thinner walls, with
constrictions at intervals and blunter ends
(fig. 3) ; no spiral streaks come out here on

boiling with nitric acid. The fibre from the
Cocoa-nut husk occurs in bundles (fig. 4) ;
when isolated or boiled with acid, the walls
are found thin, with wide, open, spiral streaks
(slits in the secondary layers) ; the ends are
blunt (fig. 5 a, b). The fibre of hemp {Can-
nabis saliva) somewhat resembles flax, but
is coarser and becomes swollen up and brit-
tle, readily breaking across, when boiled with
nitric acid (fig. 6) ; no spiral streaks. The
liber-fibres from the bundles of Miisa textilis
(fig. 7) are fine and tough, and not much
altered by boiling. Those of Bcehmeria
nivea (fig. 25) are coarse, rough on the out-
side ; they swell up and exhibit marked spiral
slits when boiled ^Yith acid, and also distinct
lamination of the thick wall (fig. 25 c). Boeh-
meria Piiya (fig. 26) closely resembles the
former ; but the spiral striation is not very
evident, and the wall sphts readil_y in the
longitudinal direction (fig. 20 c). The spiral
striation is well seen in fig. 30 of PI. 48,
which represents the end of a liber-fibre from
Tinea minor after boihng with nitric acid.

The liber-bimdles of bark are sometimes
set free as loose stringy fibres by the decay
of the outer parts of the bark, as in the vine.
Clematis, &c. In some plants they take a
wavy course, anastomosing laterally so as to
form connected reticulated sheets over the
cambium : in the Lime {Tilia) these sheets
may be detached by maceration, and they
form bast, the material used for matting,
&c. In the Thymeleace.^ (lace-bark
trees) the annual layers of liber can be
detached from each other, and form sheets
of fibrous tissue, sometimes firm and tough,
sometimes almost as delicate as muslin.

BiBL. Mohl, Bot. Zeit. xiii. 873 ; Schacht,
Pflanzenzelle, 208; Ann. Sc. Nat. 4 s(5r. viii.
104 ; Hachs, Bot. 121 ; Henf rey-Masters, i?oi!.

See also under Laticifeeous Tissue.

LICEA, Schrad. — A genus of Myxomy-'
cetes, growing on damp rotten wood, in
garden frames, &c., with the peridia elon-
gate, grouped together, of only one layer,
and containing few or no filaments among
the spores. Four species are described as
British, of which L. fragifonnis, Nees, is
not uncommon on wet very rotten wood,
moss, &c.; the groups of peridia just before
maturity somewhat resembling a straw-
berrv, afterwards brownish.

BiBL. Berk. Br. Fl. ii. pt. 2. 321 ; Ann.
N. H. 2 ser. v. 307 ; Greville, Sc. Crypt. Fl.
pi. 328 : Fries, Syst. Mycol. iii. 195 ; Sum.
Veg. 458.

LICHENOP'ORA, Def.— A genus of

LICHENS.

[ 4G3 ]

LICHENS.

Cyclo<toniatou3 Pnh'zoa (Tubulipora, pt.,
Jolinst.). Eoiir species; on niaiiiie zoo-
phytes, stones, and shells. (Hincks, Pohjzoa,
47L)

LICHENS.— A class of Thallophytes or
cellular plants standing between the Algae

Fig. 305.

Sphajrophoron coralloides.

Thallua with apothecia .

Nat. size.

and the Fungi, exhibiting in the rarious
genera relations sometimes approaching very

Fig. 396.

Fi<r. 397.

Fig. 396. Borrera ciliaris. Thallus with apothecia.

If at. size.
Fig. 397. Opegrapha atra. Thallua with lirellse. Nat.

size.
Fig. 398. Section of thalamium. Magn. 150 diamg.

closely to the one, sometimes to the other of

these two classes. The parasitic Lichens,
such as Abrothallus, being destitute of
a free thallus and of green gonidia, are un-
distinguishable from Fungi by any definite
character.

The Lichens are almost universally either
dry incrusting bodies, growing upon bark
of trees, stones, earth, &c., as a pulverulent,
or rough and horny, or laminated and mostly
wrinkled and curled crust (fig. 397) ; or as
horny or leathery, foliaceous or shrubby,
ragged or bristling patches (fig.«. 395 & 39*3),
seldom rising much from the surface which
they overgrow ; of grey, greyish green,
brown, yellowish, or even reddish colour,
and with a dead, pulverulent, and opaque
surface. Some, however, are parasitic on
other Lichens, as AbrotJialliis, or upon li\ing
leaves, as Strigula. They derive their
nourishment from the air ; and are usually
recognized by their dry crustaceous habit,
and the presence of gonidia.

In the simplest kind of Lichens, the
thallus consists of microscopic branched
filaments (liyphce^, penetrating among the
superficial layers of the cells of the bark or
epidermis upon which the plants grow.
These filaments usually present globidar
cells here and there arising from them,
filled with green matter, which are capable
of reproducing the plant when detached ;
they are called gonidia, and are regarded as
analogous to the huds of the Fowering
plants and the cellular gemmce of the higher
Cryptogams. The gonidia consist either of
simple cells containing green gi'auidar
matter (PI. 37. fig. 6^), or of clusters or
strings of green granules, when they are
called gramda gonima (PI. 3.5. fig. 13).
Sometimes these granules form spherical
concretions upon the thallus, and are called
cephalodia. The gonidia have been stated
to produce zoospores ; while these again are
declared to be granules in molecular motion.
In the simple forms here alluded to, the
gonidia are not sufficiently numerous to give
a coloured tinge to the structure as seen by
the naked eye ; in some even the filaments
make no show, while in others they form
whitish patches {Opegraplia, Verrucaria).
In the forms rather more developed we find
a layer of globular epidermal cells, with
whitish contents, closely coherent together,
constituting a " cortical layer " covering tlie
upper surface, to which the filamentous
structure or hypothallus then forms the
" medullary layer.'' The crustaceous lands
overgi'owing stones have this filamentous

LICHENS.

[ 4G4 ]

LICHENS.

medullary layer very solid ; and in some of
them its lowest filaments are seen growing
out all round the borders, in the direction
in which the plant is extending, the upper
filaments with the gonidia and the cortical
layer by degrees overgrowing these lowest
filaments, which in the meantime have
extended further out. Some of the crus-
taceous Lichens grow out in more or less
regular lobes at their borders, and thence
lead to the pseudo-foliaceous forms, of which
the common Parmelia {F/ii/scia) parietina,
the yellow Lichen so abundant on walls,
and Borrera ciliaris, common on branches
of trees (fig. 396), may serve as examples.
The thin paper-like thallus of the former
exhibits /oM/- distinct regions (PL 37. fig. 2) :
— 1, on the upper face a layer of thick cells,
firmly connected together, coloured yellow
at the sui'face (upper cortical or epidermal
layer) ; 2, a layer like the preceding, but
white, forming the inferior surface of the
thallus (loicer cortical or epidermal layer) ;
3, beneath the upper cortical layer lie the
gonidia ; and 4, under these he the vxedul-
lary filaments forming the central substance,
at the upper part of which He the gonidia
arising from these filaments. These are in-
terlaced and imprison air between them.
From the lower face arise laminae or fibrous
processes, like roots (rJiizincs), serving as
cramps by which the plant attaches itself to
the surface on which it grows. In Peltiyera
canina there is no inferior epidermal or cor-
tical layer, the filamentous medullary struc-
ture forming the irregidar veined surface,
prolonged here and there into pseudo-radical
processes. In Endocarpon and other fronds
of solid textm-e, the medullary layer is
formed of slender linear cells, closely packed,
with few air-passages. The species of Cla-
donia exhibit a structure of the thallus
intermediate between that of the foliaceous
kind just referred to and the shrubby sort.
In the foliaceous expansion resting on the
ground, of C. pyxidata, for example, we
detect the upper epidermis, next the goni-
dial layer, which again rests on the closely-
felted filamentous medullary substance. In
the branches of C. rangiferina, as in a great
number of its congeners, there is no well-
defin( d epidermis. The branches are tubes,
vacant in the centre, formed of a cartilagi-
nous structure, in which only two zones can
be distinguished, the inner and more solid
of which is composed of almost simple, pa-
rallel, solid filaments intimately glued toge-
ther by mucous substance ; the outer zone

is formed of a felted mass of filaments, like-
wise solid, but branched and divaricated.
The solidity of these filaments arises from
the obliteration of the cell-cavity by second-
ary layers on its walls, giving the filaments
a horny texture. In the outer loose layer
are found scattered groups of gonidia. In
Stereocaulon denudation the branches are
solid and formed exclusively of parallel
filaments, as is the case also with those ox
Hamalina scopulorum. In Evernia vulpina
there is a solid axis formed of parallel ti la-
ments enclosed in a layer of interlaced
fibres, between which and the horuv coat,
which is either solid or very obscurely cel-
lular, gonidia are here and there to be ob-
served.

In many Lichens, when exposed to excess
of moisture, the proper fructification is not
developed, and the gonidial structure is
produced so abundantly as to burst through
the superficial cortical layer and become
naked, giving a mealy appearance to the
thallus. Lichens reproduced by gonidia
commonly grow at first into a pulverulent
stratum by the multiplication of the cells,
giving rise to the forms which were at one
time thought distinct genera, such as Le-
praria.

The gonidia have been stated to produce
motile zoospores; but these are now con-
sidered molecular granules.

The fronds of Vollema are remarkable foi
their gelatinous texture, and approach the
Nostochacese (Algaj) in the simphcity of
their structure ; thus, the thallus of C.
cheileum consists of branched and coloiuless
filaments or tubes imbedded in an abundance
of mucilage ; in Cjacohecefolium, there exist
in addition very numerous granula gonima,
almost all arranged in long beaded lines
(PL 37. fig. 13), some being larger than
others, the whole mixed uith the con-
tinuous filaments and imbedded in mucus.
Both species have long, wdiitish, branched,
filamentous pseudo-radical processes.

Putting aside the gonidia or gemmule-
cells of the thallus, the reproductive organs
of the lichens are of three kinds: — 1, the
apofhecia, which, according to their forms,
receive diflereut names, and are all charac-
terized by producing the sacs (thecce) con-
taining spores; 2, the spermogonia, which
some regard as antheiidia, and which pro-
duce extremely minute cylindrical bodies
{spermatia) growing at the ends of short
pedicels, from which they are ultimately
detached, like the spores of many P'ungi j

LICHENS.

[ 465 ]

LICHENS.

and, 3, pycnidia, in which are developed
sti/lospores like those of Fungi.

The commonest form of the apothccia is
that of sessile or stalked disks or cushions,
flat, convex, or hollowed into a cup (fig.
396) ; in other cases they are linear ; these
open forms characterize the formerly-called
Gymnocarpous Lichens. While in the
Angiocarpous genera the apothecia or rather
perithecia are closed globular receptacles or
conceptacles, analogous to those of the Sphce-
ri(B among the Fungi, and opening at the
summit to discharge the spores (fig. 39o).
The apothecium may he composed of two
parts — the tludamium or hymeninm, and the
excipulum. The excipulum, when present,
sometimes forms a cup-like envelope derived
from the thallus, and of the same colour
(thaUine), or it may differ in colour and
texture, in which case it is termed proper.
Or it may entirely or partly surround the
thalamium and theca?, and then forms the
peritheciiim. The t/iahi»tiio>i is represented
by the body of the apothecium, open or
closed; and the layer of its cells immediately
lining the bottom of the cup, shield, or
conceptacle is sometimes called the hypo-
thecium, which bears the thec(S and the
paraphyses (fig. 398) ; the latter are filiform
or clavate cells (PI. 37. figs. 6 & 12), pro-
bably abortive thecse, among which they
are intermingled ; both these and the thecse
stand perpendicularly upon the hypothe-
ciuni, being surrounded by a gelatinous sub-
stance— the gelatina hymenea. The thecce
(PI. 37. figs. 6 & 12) are usually ovoid or
elongated cells with thick walls, containing
the spores ; the thecse are shorter than the
paraphyses surrounding them ; and the
whole are usually glued firmly together by
their contiguous lateral surfaces.

The spores consist of two layers, an epi-
spore and an endospore ; the former are tinged
blue with tincture of iodine, and present
many points of difference in different genera
and species. In Verrucaria muralis they
are ellipsoid, colourless, perfectly smooth
and semitrausparent, containing gi-anular
matter ; while in V. epidermidis and ato-
maria they are bilocular bodies, representing
a pair of obovoid cells adherent by their
thick ends. In their earlier stages of de-
velopment they appear solid ; subsequently
four nuclei or oily globules are seen in them,
each occupying a spherical cavity. The
membrane of the spore then becomes thin-
ner, and finally its two cavities coalesce into
one. When ripe, these spores are about

1-1. "jOO" in length and about 1-4000" broad.
There are eight in eacii theca, and they are
separately enveloped in a mucilaginous coat.
The spores are largest in the genus Pertu-
sdria. Those of P. communis are visible to
the naked eye ; and observed in water soon
after emission from the thecse, they are not
less than 7-1000" to 8-1000" long by 5-1000"
broad. Their simple cavity is filled with
granular semitrausparent matter, usually
with oil-globules of various sizes. The
epispore is very broad, transparent, and
formed of several lamellae ; these also are
coated with mucus. The genus Par^nelia
(Physcia) offers both simple and bilocular
spores. Of the former, P. purietina gives
an example, though in some cases a trans-
verse partition is formed, and this is the
normal state in P. stellaris (PI. 37. figs. 6 &
7). In Ptltigera (PI. 37. fig. 11) the spores
are elongated. In Collema and other genera
the spores are divided into fom- chambers
by three transverse septa.

In several species of Lecanora, Lecidea, .
Urceolaria, &c., a more complex form of
spore exists, longitudinal together with
transverse septa dividing the cavity into
several series of chambers. Those of Urceo-
laria (PL 37. fig. 17) have eight or ten
compartments ; those of Lecidea urceolata,
Thelotrema lepadina, Umbilicaria pushdata
(PL 37. fig. 18), and other Lichens, called
muriform spores, have a much larger num-
ber of little cavities, each containing a
distinct nucleus.

The emission of the ripe spores takes
place in the same way as in the Pezizce,
Hehellcp, Sph(eri<e, and many other Fungi
of the same kind. If a portion of the
thallus, moistened, is placed in a common
phial, with the apothecia turned toward
one side, in about eight or ten hours the
surface of the glass opposite each apothe-
cium will be found covered with patches of
spores, easily perceptible by their colour,
these having been projected from the apo-
thecia with force. If placed on a moist
surface, and a slip of glass laid over them,
the latter will become covered with them
in the same way ; and Tulasne states that
they are projected to a distance of more
tlian half an inch from the theciferous layer,
the spores being emitted continuously for a
long time. The experiment may be tried
either in winter or summer, and has been
made with success on several common spe-
cies of Parmelia, Lecanora, Peltiyera, Col-
lema, Borrera ciliaris, Verrucaria muralis,

2h

LICHEXS.

[ 466 ]

LICHENS.

Emlocaiyon hepaticnm, Pertusaria, Urceo-
laria, Opegrapha, &c.

Eight is generally set down as the normal
number of spores in each theca ; but this is
not universal here any more than in the
Ascomycetous Fungi ; some species of -EVi-
docarpon, Parmelia, &c. have polysporous
thecffi containing a considerable number,
"while there ai'e often less than eight.

Spermogonia. The Lichens exhibit another
form of reproductive organs, which are
liable to be confounded with Sphcrronemei
and other Fungi growiug on the Lichens,
or with parasitical Lichens in similar po-
sitions. They form black or brown points,
usually near the margins of the thallus
(PI. 37. fig. 1), and have been found in
Borrera, Parmelia, Sticta, Cludonia, CoUema,
Opegrapha, Sphcerophoron, Lichina, Endo-
carpon, kc, and seem to be universal.

The spermogonia are hollow pustules (PI.
37. figs. 3 & 13) tilled with lilaments (sperma-
tophorcs, PL 37. tig. 3) producing extremely
minute bacilliform corpuscles (usually sper-
matia). They are immersed in the sub-
stance of the thallus (PI. 37. figs. 2 & 13),
and are perceptible externally only by a
little projection, if at all; in rare cases they
are free and borne above the thallus (some
Cktdonice, Cetraria, Gyalectce, &c.). Their
ordinary form is globular, ellipsoidal, or
in-egularly oblong, sometimes sinuous.
They have either a simple undivided cavity
(PI. 37. figs. 13 & 16), or are multilocular,
divided in different ways into a variable
number of separate chambers or narrow
cavities, communicating with a common
orifice, the ostiole or jwre of the apparatus.
This structure bears a close relation to that
usual in the Coniomycetous Fungi Cgtispora,
Septoria, &c., and bears testimony to the close
connexion between the Lichens and Fungi.
The spermatia are regarded as analogous to
the spermatozoids in the antheridia of the
higher Cryptogams.

Vycnidia and Stghspores. Pi/C7u'dia are
dark-coloured conceptacles, found on Le-
cidea and Scutnla, resembling ihe perithecia
of the Sphceria>, sessile on the thallus, and con-
taining simple filaments (basidia), bearing
isolated spores on their apices (sfi/lo,sp(»rt<).

The so-called spermogonia and pycnidia
appear to be in some cases parasitic Fungi.

Chemical reagents are useful in the dis-
crimination of Lichens. Thus, iodine so-
lution will tinge the mature spores or the
gidatina hymcnea of some Lichens blue, or
red without a preparatory blue tinge. So-

lution of caustic potash produces in the
thallus of some Lichens a persistent yellow
colour, which in others changes to a red ; or
if no reaction takes place, solution of chloride
of lime produces a red or yellow colour.
These reactions must be observed in sections.

The long-known resemblance of the
gonidia of Lichens to numerous forms of
the lower Algae, and the similarity of the
thecEe of Lichens to the asci of Ascomy-
cetous Fungi, has of late years given rise
to the theory (Schwendener's) that the
gonidia of Lichens are really Algte ; the
Lichens being Ascomycetous Fungi, living
and growing upon them as parasites. The
Algse which, according to this view, form
the gonidia, are usually species of Palmella,
Protococcus, Kostoc, &c., rarely of Confer-
vaceae ; and when free, continue to grow
and reproduce, still retaining the Alga-
form. But when the germinating spores of
Lichens come into contact with them, the
hyphse sm-round the cells, enveloping them,
and on further growth a perfect Lichen is
formed. This question cannot at present
be considei'ed as settled ; for while, accord-
ing to Bornet, the hyplije never produce
gonidia, according to Miiller this occurrence
most positively does take place. On the
whole, it appears that Schwendener's in-
genious Lichen-theory will have to be
considered one of the modern natural-his-
tory romances.

The Lichens are divided into four families :

Byssacei. -Thallus byssaceous or finely
filamentous, the granula gonima in a thai-
line sheath.

CoLLEMACEi. Thallus gelatinous.

Myrangiacei. Thalamium with cellu-
lar cavities, and superimposed theciferous
cavities.

LiCHENACEi. Thallus not gelatinous ;
variable in colour and form, either filamen-
tous, foliaceous, squamous, or crustaceous ;
gonidial layer usually distinct.

BiBL. Tulasne, Ann. Sc. Nat. 3 S(5r. xvii.,
& Compt. rend. 1851 ; Montague, Diet, d'hist.
nat. 1846; Itzigsohn, Bot. Zeit. viii. & ix.;
Flotow, Flora and Bot. Zeit.; Lindsay, Pop.
Lichens ; Famnitzin and Boranetzky, Ann.
Sci. Nat. ser. o, viii. ; Leightou, Brit. Lich,
Flora ; Ilenfrey-Masters, Bot. ; Nylander,
Lichenogr. Europ., &, Flora, 1879 (Jn. Mic.
Soc. 1880, 31o, colow) ; Reess, Monatsb. Bcrl.
Al: 1871 ; Bornet, An. Sc. N. 1873, xvii.;
Scliwcndener, Aligeli's zciss. Bot. 1860, '02,
'G8, Scyilgent.gp. Flecht. Gonid., 1869; Archer,
Jn. Mic. Soc, xiii., xiv {all the papers on

LICHINA.

[ 467 ]

LIGAMENTS.

Schio. Lich.-theoni fromimS <ol873); Vines,
Qit. Mie. Jn. ]"878, xviii. 144, 4:38, later
papers on the same ; Thwaites, Atin. N. H.
1877, XX. 38G; Frank, Krust. Flecht., Cohn's
Beit. ii. 123; Stalil, Entw. d. Flecht. 1878:
Minks, Flora, 1878, Grevillea, 1879, vii.
89, & Grenz. zxl\ Fl. & Pihe, 1881 ; Miil-
ler, Ann. N. H. 1881, viii. 427, & Grevillea,
X. 87 (Phillips) ; Crombie, Grevillea, vii.
143 ; Cooke, ibid', vii. 102, 117.

LICHI'NA, Ag. — A genus of Collema-
ceous Licheus, allied to Collema and
Ephebe in many respects, formerly in-
cluded among the Algae on account of their
growing on the sea-shore (near high-water
mark), "but having the thallus of a lichen
and bearing true apothecia and spennogonia.
The globose apothecia occur at the ends of
the branches of the thallus ; in L. j)yi/mcea
the spermogonia occur underneath the apo-
thecia, in L. conjinis at the apices of the
branches and often on the apothecia. The
spores, 8, simple, appear generally to adhere
to the walls of the thecse, which break up.
Spermatia oblong.

BiBL. Greville, Alff. Brit. pi. 6 ; Leigh-
ton, Br. Lich. Fl. 11.

LICMO'PHORA, Ag.— A genus of Dia-
tomacese.

Char. Frustules in front view cuneate,
elongate, radiating in a fan-shaped manner
from a branched stipes ; side ^iew (valves)
convex, inflected at the larger end and fur-
nished with transverse strise (rows of dots).
Marine.

L. Jlahellata, S. {radians, K.) (PL 17. fig.

3).

The species (one other British, Sm., five
in all, Kiitz.) are doubtfullv distinct.

BiBL. Br. JDiat. i. 85; Kiitz. Bacill. 123,
and Sp. Ah/. 113.

LICNO'PHORA, CL— A genus of Peri-
trichous Infusoria ; resembling Trichodina,
but the anterior portion obliquely flattened,
and partly involute. Two species, on
Doris, marine Flanarice, Szc. (Kent, Inf.
651 ; Clap. Ann. Sc. K. 1867, viii.)

LIEBERKUH'NIA, CI. & Lachm.— A
genus of Reticularian Rhizopoda. Oviform,
with very thin test ; nucleus and contractile
vesicle unknown; vacuoles present ; pseudo-
podia very long and reticular, branching
from a single stem, which is coated with an
extension of the filmy sarcode covering the
surface. 1 species ; fresh water at Berlin,
sea-water at Tenby.

BiBL. Clap. & Lachm. Etudes, 465 ; Sid-
dall, Qu. Mic. Jn. 1880, 141.

LIEBERKUHN. Intkod., p. xxi.

LIGAMENTS and Tendons.— With the
exception of the elastic ligaments, which
are noticed under that head, the structure
of ligaments and tendons is essentially the
same. They consist of fibrillar connective
tissue, with a small quantity of elastic

Magnified 60 diameters.

Transverse section of the tendon of the tibialis posti-
cus ; human : a, secondary bundles ; b, larger nuclear
fibres ; c, interstitial areolar tissue.

Fig. 400.

i

Magnified 20 diameters.

TransTerse section of a tendon of a calf: a, secondary,
6, tertiary bundles ; c, nuclear fibres, obliquely divided ;
d, interstitial areolar tissue.

2h2

LIGAMENTS.

[ 468 ]

LIGAMENTS.

tissue. The fibres or fibrillai of tlie connec-
tive tissue are very minute, longitudinal,
parallel, closely connected, and pursue a
straight or undulatory course. Their union
into bundles is sometimes very indistinct,
and only to be shown by drying transverse
sections and afterwards treating them with
alkalies. In other instances the bundles
are easily recognizable, of a polygonal,
rounded or elongated form (fig. 400), and
connected by loose interstitial areolar tis-

sue.

The elastic tissue of tendons exists as
slender nuclear fibres, sometimes forming
rows of narrow spindle-shaped cells con-
nected by slender processes, at others uni-
form libres, or isolated spindle-shaped cells.
These are placed at regular distances apart,
between the bundles of areolar tissue.

AVhen tendons are in contact with bones,
they frequently contain cartilage-cells, either
isolated or arranged in rows (hg. 401, c) ;
these sometimes undergo ossitication.

The aponeuroses, uiscia3, and tendinous

Fig. 401.

\ c

■-■ '^'A ^ "■•• --^ \-^ vv:A
%^1^ '^x'^'\> ^\nW \- A \\;>%^W'^\

J

„. \

I

,-(*

A

..b

ilagnifled 300 diameters.

Portion of the tendo AchiUis attached to the o5 calcis ; human : A, bone with lacunae a, medullary and fat-cells 6 ;

U, tendon with llbrilla; and cartilage-cells c.

sheaths consist of the same elements, but
in various proportions and differently ar-
ranged according to their functions, — some-
times the areolar libres being predominant,
the structure agreeing with that of teiuhm,
whilst at others the elastic tissue is greatly
developed (fig. 403). Some of these tissues
also contain cartilage-cells.

The intervertebral ligaments consist of
fibro-cartilage, surrounded by osseous tissue ;
the centre is soit and containing concentric
cartilage-corpuscles (fig. 101, p. 135).

Fig. 402.

#

Magnified 350 diameters.

Cartilage-cells from the membranous ligament sur-
rounding the popliteua muscle': (7, cell with one nucleus;
6, cell witli two nuclei : c, cell containing one, d,, two
secondary. cells, the contents of both of which are more
consistent.

LIGNINE

LIME

Magnilled 450 diameterg.
Elastic fibres from the inner part of the fascia lata, human ; densely interwoven and forming an elastic membrane.

BiBL. KoUiker, Mih. An. i. ; Heule, All-
gem. An. ; Donders, Mulder s Plnjs. Chem. ;
Frey, Hist 240.

LIGTsINE. — A modified condition of
cellulose is obtained from old wood-cells,
and called by this name. It difters in its
leactions from pure cellulose, being coloured
vellow by sulphuric acid and iodine ; but
after boiling in nitric acid and washing,
tincture of iodine and water give it a blue
colour. See SECO^•DARY Deposits.

LIMBOKIE^.— A family of Angiocar-
pous or closed-fruited Lichens characterized
by rounded apothecia closed in by a carbo-
naceous special perithecium, finally bursting
in various ways, containing a somewhat,
waxv nucleus, which grows hard.

British genera : Pyreiiothea, Strir/ula.

LIME, SALTS 6V.

Carbonate of lime. This substance is well
known as forming chalk, marble, &c., andas
occurring in hard animal structures, as bone,
shell, &c. It is not unfrequently met with
in the form of granules as a component of
various animal secretions, as the urine, &c.
In this liquid, it sometimes, but rarely, also
occurs in little spheres or disks, consisting
of groups of radiating needles. This we
first found to be the case in human urine
(PI. 13. fig. 8) ; but it was subsequently
detected in that of herbivorous animals, as
the cow and the horse (PI. 1;3. fig. 7), in
which its occurrence is common. It is also

a component of otolithes, in which it exists
either as granules or minute prisms, often
with six sides and trilateral summits. From
river- and spring-water it is usually deposited
in irregular and imperfect forms (PI. 13.
fig. 6), all of which consist of grouped nee-
dles. Sometimes it assumes the rhombohe-
dral form, as in the shell of the oyster (PI. 45.
fig. 10) and frequently in chemical solutions.
When treated with a dilute acid, after having
been thoroughly washed in a watch-glass,
it is dissolved with effervescence from the
escape of carbonic acid gas. During the
solution it first becomes more transparent,
exhibiting the internal crystalline structure,
and frequently a concentric or nuclear ap-
pearance, which finally disappears. When
derived from animal secretions, it leaves
undissolved an organic cast of the original,
provided the acid be not too strong, or its
action too long continued. If the number
and size of the minute bodies be relatively
very small in proportion to the amount of
water, on adding the acid, effervescence
will not occur, the water holding in solution
the carbonic acid evolved. The presence
of the lime may be tested in the ordinary
way, by the addition of oxalate of ammonia,
when the precipitate is insoluble in acetic
acid, or by adding dilute sulphm-ic acid,
when crystalline needles of the sulphate of
lime (PI. 10. fig. IG) are formed.

The spheres or disks naturally occurring

LIME.

[ 470 ]

LIMNIAS.

in the urine, are closely imitated by those
formed in urine to which chloride of calcium
has beeu added, and which has been subse-
quently kept for some time.

Lactate of lime may be obtained by acting
upon carbonate of lime with lactic acid. It
is soluble in water and alcohol. The mi-
croscopic crystals consist of tufts of delicate
radiating needles (PI. 11. fig. 19).

Oxalate of Ji7ne. This salt exists in solu-
tion in the contents of many vegetable cells
combined with a proteine compound ; it is
also probably a normal constituent of the
human blood in small quantity, combined
and dissolved as in vegetables.

In the cells of plants it is very frequently
deposited in a crystalline form, constituting
Raphjdes. From human blood it has been
obtained in crystals by treating the alcoholic
extract with acetic acid. It is very commonly
met with in the crystalline form in various
secretions of animals, as the urine, the mucus
of the gall-bladder, that of the surface of the
pregnant uterus, the liquid of the allantois,
the contents of the Malpighian vessels and
the so-called true renal vessels of insects,
cysts, &c.

Its most characteristic form is the square
flattened octahedron (PL 13. fig. 9) ; but it
also occurs in tbe form of the square prism
terminated by quadrilateral pja-amids, of fine
needles, and in that of a flattened body with
an ellipsoidal outline, frequently constricted
so as to resemble a dumbbell, or variously
excavated at parts of the surface (PL 13.
figs. 11 & 12). It may be obtained artificially
in most of these forms (PL 13. fig. 13), by
dissolving artificial oxalate of lime in dilute
nitric acid and evaporating ; some of the
forms thus obtained resemble those of car-
bonate of lime. When obtained by mixing
oxalate of ammonia with soluble salts of
lime, as chloride of calcium, kc, the crystals
are generally peculiar ( PL 13. fig. 14), al-
though sometimes the regular octahedra
are obtained.

It is insoluble in hot and cold water,
acetic acid and ammonia, but is soluble in
dilute mineral acids without efi'ervescence.

Phosphate of lime. This salt is most fre-
quently deposited from animal liquids in
an amorphous or granular state. It may be
obtained in the crystalline form by mixing a
solution of phosphate of soda with chloride
of calcium. The crystals are mostly thin
rhombic plates (PL 10. fig. 17).

They are soluble in acetic and dilute
mineral acids -R-ithout eflervescence, but not

in potash or water. Some of the compound
crystals resemble those of the ammonio-
phosphate of magnesia, from which they
may be distinguished by the addition of
dilute sulphuric acid, which causes the for-
mation of needles of sulphate of lime.

Sulphate of lime. Well known as form-
ing gypsum, alabaster, selenite, &c. It rarely
or never occurs in the crystalline foi-m in
animal or vegetable products. When rapidly
formed in chemical testing, the crystals
consist of minute needles or prisms (PL 10.
fig. 16) ; when more slowly formed, these
are larger and mixed with rhombic plates.

The crystals are but little soluble in water,
and not in acetic or the dilute mineral acids.
They are sometimes formd in bottles con-
taining spirit in which marine animals have
been preserved.

Medicinal precipitated sulphur is very
commonly adulterated with sulphate of lime.
The microscope at once enables the crystals
of the salt to be recognized.

Urate of lime. See Ueates.

See E APHIDES and Ubinaby Deposits.

BiBL. That of Chemistry, aximal.

LIMNAC'TIS, Ktz.— A genus of Eivu-
lariacese, Confervoid Algse.

Cliar. Filaments pseudo-ramose, subfas-
ciculate, sheath more or less distinct. L,
parvula ; Lincolnshire.

BiBL. Eabenh. Fl. Alg. ii. 210.

LIMNADEL'LA, Girard.— A bivalve
Phyllopodous Entomostracon, near Es-
theria.

BiBL. Girard, Proc. Phil. Ac. i. 184, &
vii. 34 ; Grube, Wiegm. Arch. 1865, 73.

LIMNA'DIA, Brougn.— An aquatic bi-
valved Phyllopod, with thin oval valves,
enclosing an elongated body, having a short
and a natatory pair of antennfe, oral appa-
ratus, twenty-two or more pairs of branchial
lamellfe, and a bifid tail.

BiBL. Brongniart, Mem. Mus. Hist. Kat.
vi. pi. 13 ; Desmarest, Crust. 378 ; Milne-
Edwards, Hist. Nat. Crust, pi. 3o. f. 7;
Baird, Zool. Proc. 1849, 86, pi. 11. f. 1 ;
Grube, Wiegm. Arch. 1865, 61, pi. 8; Lere-
boullet, Ann. Sc. Kat. Zoo/. 5, v. 283, pi. 12.

LIMNE'TIS, Lov4n.— An aquatic bi-
valved Phyllopod, related to Limnadia and
Esther ia.

BiBL. Lov^n, K. V. Ak. Hand!. 1845,
203; Baird, Zool. Proc. 1862; Grube,
Wiegm. Arch. I860, 7L

LIMNIAS, Schrank. — A genus of Eota-
toria, of the family Floscularisea.

Char. Eyes (when young) two, red ; ur-

LIMNICYTIIERE.

[ 471 ]

LINGULINA.

ceoli or sheaths single ; rotatory organ with
two lobes. Teeth forming a row in each jaw.

L. ceratophylU (PI. 43. lig. 45). Urceolus
at first wliitish, subsequently becoming
brown or blackish, smooth, or in conse-
quence of its viscidity covered with foreign
bodies. Freshwater; length 1-24 to 1-18",

BiBL. I'^hr. Infm. 401.

LlMNlCYTfiE'RE, Brady.— An Ostra-
code, allied to Cythere, the antenniB having
seta3 instead of spines, and the valves being
hiu, and spinous or tubercled.

BiBL. G. S. Bradv, Linn. Tr. xxvi. 419.

LIMNOCH'ARES, Latr.— A genus of
Hydrachnea (Acarina).

C. aqiiatica (holosericea) (PI. 6. fig. 27),
the only species. It differs from other
water-spiders by its walking instead of
swimming.

Body very soft and often spontaneously
variable in form ; epidermis covered with
little conical granules (?) ; no hairs upon the
body, and but few upon the legs ; eyes at-
tached to a lanceolate scaly piece (d), and
surrounded by hairs; rostrum partly con-
cealed beneath the skin, the anterior ex-
serted half (b) cylindrical and accompanied
by the palps, the last joint of which is very
slender and obtuse ; by pressure the broader
base of the rostrum is made to protrude (/);
tarsi (c) thickened at the end, with large
claws ; coxEe of foiu* posterior pairs of legs
longer than the others, which is contrary to
what occurs in Hydrachna, Ata.v, &c. ; coxae
of the two anterior pairs of legs closely
approximate, as are also those of the two
posterior pairs (e) ; but the two groups are
widely separated.

Larvae with six legs, a large head-like
rostrum, with two large palps and two black
lateral anterior eyes, fixing themselves on
the head of Gerris lacustris ; they subse-
quently detach themselves, faU into the
water, and pass their nymph-stage under
submersed stones, the perfect animal making-
its appearance at the end of fifteen days.

BiBL. Duges, Ann. Sc. Nat. 2 ser. i.
159 ; Gervais, Walckenaer's Arachn. 208 ;
Koch, Dents. Crustac.

LIMXODIO'TYON, Kiitz.— A genus of
Protococcaceae.

Char. Cells angular from mutual pres-
sure, forming membranous layers, in a
parenchymatous form; multiplication by
gonidia.

L. R(£merianum (PI. 52. fig. 14), in
pools.

BiBL. Rabenh. FL Alg. iii. 61.

LIMNO'RIA, Leach. — A genus of ma-
rine Crustacea, Order Isopoda, and family

Asellota.

L. terebrans (PI. 36. fig. 27) ia of interest
on account of the great ravages which it
commits in submerged timber, as the piles
of piers, flood-gates, docks, &c., which it
perforates in every direction. Head large,
rounded ; antennae four, of nearly equal
length ; ej^es two, lateral, black, composed
of about seven ocelli ; body elongato-sub-
cylindrical, thorax with seven joints, legs
seven pairs, formed for walking ; abdomen
six-jointed, the last joint large, suborbi-
cular, and with two styles ; length about
1-6". It contracts into a ball when dis-
turbed.

BiBL. Leach, Linn. Tr. xi. 370 ; Cold-
stream, Edin. New Phil. Jn. 1834 ; Dalyell,
Wonders of Creation, i.

LIXDIA, Duj. — A genus of Rotatoria, of
the familv Hydatiuaea, E. (Furculariua,
Duj.).

Cltar. Body oblong, almost vermiform,
with transverse folds, rounded in front, but
no rotatory organ, cilia, or eye ; tail-like
foot with two conical and short segments
or toes ; jaws very complicated (and im-
perfectly described).

L. toridosa (PI. 43. fig. 40). Freshwater ;
length 1-75".

BiEL. Duj. Infus. 653; Cohn, Sieb. 8^
KijU. Zeit. 1858, 286 ; Pritch. Inftis.

LIjS'DSzEA, Dryander. — A genus of
Lindsaveae (Polypodiaceous Ferns). Exotic
(fig. 404).

Lindsoea.
A pinnule. Magn. 10 diams.

LINGULl'NA, D'Orb.— A hyaline sti-
chostegian Foraminifer, difi'eiing &om No-

LINGULINOPSIS.

[ 472 ]

LITOSIPHON.

dosan'u in being laterally compressed and
having a slit-like aperture.

BiBL. Carpenter, Introd. 163.

LINGULINOPSIS, Pveuss.— This may
be defined as a Luk/uUuu having its early
chambers coiled ; or a MarginHlina much
compressed and opening with a rift.

BiBL. Reuss, K. bo/nn. Ges. Wiss. 18G0.

LINOP'ODES, Koch.— A genus of Trom-
bidiua (Acarina); with the legs 6-jointed,
the anterior pair very long and slender.
Three species ; among moss ; red or orange,
(Murrav, Ec. Ent. \-12 ; Hermann, Apter.)

Ll'NUM, L. See Flax.

LIOSl'PHON, Ehr.— A genus of IIolo-
trichous Infusoria, fam. Trachelina.

Char. Resembles Nassula, but the frontal
region jn-olonged. 1 species.

BiBL. Pritchard, Infus. p. C27,

LIOSTEPHA'NIA, Ehr.— A genus of
Melosireoe (Diatomaceae).

Char. Frustules single, orbicular ; disk
smooth, but with a crown of rays round a
smooth space ; 3 species ; Barbadoes.

L. rotida (PI. 51. fig. 17).

BiBL. Pritchard, Infus. p. 813.

LIOTHE'UM, Nit'zsch.— A genus of
Anoplura, family Liotheidee.

Char. Antennse clavate or capitate ; max-
illary palpi conspicuous ; mouth with strong
mandibles ; tart-i with two claws.

Antenna} four-jointed ; mandibles with
two teeth; maxillary palpi long, filiform,
four-jointed ; labis-l palpi very short, two-
jointed.

The genus has been subdivided into seven
subgenera. The species are very numerous,
and are parasitic upon birds.

L. {Meiiopon) 2)aUidum (PL 36. fig. 7).
Elongate, of a pale straw-colour, shining and
smooth ; head slightly sinuate on each side,
with a dark pitchy spot before each eye.
Length 1-24 to 1-16". Common on the
domestic fowl. Other species on the par-
tridge, pheasant, and quail.

BiBL. Dennv, Monoqr. Anoplur. p. 204.

LIPAROGY'RA, Ehr.— A genus of
MelosirefB (Diatomaceaj).

Char. Frustules simple, cylindrical, each
having an internal spiral filiform band or

crest.

BiiiL. Pritchard, Infiis. p. 823.

LIPEU'RUS, Nitzsch.— A subgenus of
rhilopterm. The species are found on the
pigeon, the goose, the fowl, and the turkey.

BiBL. Macalister, Qu. Micr. Jn. 1871,
103 ; MurraV; Ec. Eid. 381; Meguiu; Faras.
88.

LIRADIS'CUS, Grev.— A genus of Dia-
tomacete.

3 species; Barbadoes deposit. L. Bar-
badensis (PI. 62. fig. 13).

BiBL. Greville, 7V. Mie. Soc. 1865.
LISTROPH'ORUS, Pagenst— A genus
of Acarina, allied to Sarcoptes. Two spe-
cies, on field-mice, rabbits, and the ferret,
the partridge, &c. The maxilte form two
flexible claspers, for clinging to the hairs.
(Pagenstecher, Zeits. wiss. Zool. xi. 156;
Murrav, Boon. Ent. 324.)

LIT'IHC ACID. See Ueic Acid.

LITIIOOYS'TIS, Allm.— A genus of
Coralliiiaceffi (Floiideous Algas), consisting
of a single species, L. AUmanni, Hass., which
has been found as an epiphyte, forming
minute white dots upon Chrysimenia clavcl-
losa. The minute dots consist of one or
more fan-shaped fronds composed of square
cells. Tlie plant is colourless, brittle, and
effervesces in acid. The fan-shaped frond
somewhat resembles in structure imperfect
or segmental fronds of CoLEOCH^^iTE.

BiBL. Harvev, Mar. AI</. Ill, pi. 14 B ;
Phyc. Brit. pi. 166.

LITHODES'MIUM, Ehr.— A doubtful
genus of Diatomaceffi. Marine.

L. tmdulatum (PL 17. fig. 4 a, front view ;
4 J, side view). Surface without markings,
very pellucid, two of the sides undulate, the
third plane and with two marginal notches ;
angles obtuse ; length of joints 1-480".

BiBL. Ehr. Abh. d. Berl. Akad. 1840;
Kiitz. Bacill. p. 136, and Sp. Alg. p. 133.

LITHOFELLINIC ACID.— Is a com-
ponent of certain concretions called bezoars,
found in the alimentary canal of Aarious
kinds of goat in Persia ttc.

It is ciTstalline, insoluble in water, readily
so in hot alcohol, but little in ether.

The perfect crystals form six-sided prisms
with truncated ends ; but when somewhat
rapidly deposited from an alcoholic solution,
they are modified as represented in PL 11.
fig. 14. With Pettenkofer's test they are
turned red.

LITIIOG'RAPHA, NyL— A genus of
Graphidei (Lichenaceous Lichens).

Char. Thallus crustaceous or evanescent ;
apothecia lirella^form, black, tumid ; epi-
thecium rimi form, margins thick, convex;
hypolhecium black, thick, entire; spores 8
or numerous, simple or 1 -septate.

7 British species. Rare.

BiBL. Leinhton, Brif. Lich. Flor. p. ,303,

LITOSIPHON, Harv.— A genus of
Punctariaceie (Fucoid Algae), with fronds

LITUOLA.

[ 473 ]

LIVER.

composed of cartilaginous filiform im-
braiK-hfd filaments, at iirrt solid, al'teiwards
tubular, composed of several rows of cells ;
epijiliYtic on Chorda filmn {L. ptmllus) and
Alaria [L. Laiuinaricc), the former 2 to (>"
long, the latter 1-4 to 1-2". The spuranges
occur either solitary or aggregated, scattered
on the surface of the filaments, which in
L. pusillus are clothed with pellucid hairs,
in L. Laniinarice smooth.

BiBL. Ilarv. Mar. AUj. p. 43, pi. 8 1) ;
Thuret. Ann. Sc. Nat. 4 ser. iii. p. 14.

LITU'OLA, Lamarck. — A protean Fora-
miniferal genus, abundaut both recent and
fossil; characterized by the test being coarsely
arenaceous, with Httle or no calcareous
cement. The shell may be unilocidar (Pro-
teonina?, Williamson). If compound, its
shape may be loosely moniliform (^Reoplucr,
Montfort), whether straight, coiled, or
irregular, fi-ee or attached (the latter
feature chai'acterizing Placopsilina, D'Orb.).
Or the chambers may be close-set and
OAerlapping, and have either a straight,
coiled, or crozier-like contour, imitating
various forms of other Foraminifei'a, such
as Ortkocerina, Nudosaria ,Flabe.Uina, Crist el-
laria, SpiroUna, Pofalia, Nonionina, Glohi-
gei'ina, Orbidina, &c, Further, the chambers
may communicate by a simple central
aperture, or by a cribriform septal plate ;
and they may be either simply hollow, or
labyrinthic from secondary gxowths. Some
with a single aperture and imdivided
chambers, and some which are labyrinthic
and cribriform, belong to Reuss's Ilaplo-
phragmimn and Haplostiche (straight).
When the aperture is of a horse-shoe shape
and subvalvate, we have the allied Hlppo-
orpina, Parker. PI. 23. tig. 18 is an irre-
gularly nautiloid, labyrinthic form (Litiiola
difformis) very common in the Chalk.

Bill. Carpenter, Introd. p. 143.

LITUO'LIDA, Carp. = Lituolid^ and
AsTROEHiziD.^, p. 332. — Besides the
coarse-grained genus Lituola (with its sub-
divisions), there are several closely related
forms which differ chiefly in the degrees of
smoothness and compactness with w^hich
the constituent sand-gi'ains, and sometimes
spicula, are set and cemented.

Botellina, Carpenter, is a long, roughly
segmented tube of sand and spicules, with
ill-defined terminal aperture. Saccammhia,
Sars, is spherical and smooth, either single
or in twos or threes united by a narrow
stolon-tube. This is found fossil in the
Lower Carboniferous strata, as well as

recent. Pilulma, Carpenter, quite spherical,
with a fissure-like mouth, is composed of
very fine sand and points of spicules. As-
frorhiza, Sandahl, relatively large, has a
coarse, iri-egularly stellate, test of loosely
aggregated sand, with pseudopodial aper-
tures among the granules, chiefiy at the
ends of the digitate radii, llhadammina,
Sars, arenaceous, with a cement containing
ferric phosphate, is tubular, forked, or
radiate, usually trifid, with a central cavity;
openings at the radial ends.

The Lituolida with fine-grained and smooth
tests are best typified by Trochanimina and
its subgenus lVehhi)ni (D'Orb., restricted).
These range from simple, attached, tent-like,
single or multiple tests ( W. hemispharica,
W. irref/idaris, &c ),to the tubular and spiral
Troch.incerta(F\. 23. fig. 14) and therotalioid
T. s<p(amata et injlata. The rotalioid and
fusuline Endothryce and the nummulitoid
Involufina, all fossil, belong to the same
category.

Valvulina, one of the Textulamid^e,
sometimes finely, sometimes coarsely arena-
ceous, is, in this character, allied to the
Lituolines and Trochamnrines ; and among
its several modifications some link it with
LHuola and others with Trochammina.
Tetraf axis has an alternation oi four, and
Valvulina (PL 23. fig. 20) of ^7j?ee chambers.

The Lituolida are represented in every
existing sea, and in every geological forma-
tion as far back as the Carboniferous.

BiBL. Carp. Introd. 140 ; Bescr. Cat. 3Iic.
Soc. April 1870, 4 ; Parker, Jones, and
Brady, Phil. Tr. civ. 406; Monogr. Crag
For.^Pal. Soc. 25 ; Brady, Mon. Carl. For.,
Pal. Soc. 1876 ; Qu. Mic. Jn. n. s. xxi.

LIVER. — The glandular organ which
secretes the bile.

On examining the surface or a transverse
section of the liver with the naked eye, it
usually presents a mottled appearance,
numerous spots of a dark or light red
colour being surrounded by a margin of a
paler or darker colour. These spots cor-
respond to the lobules of the liver.

The lobules are rounded or polygonal, and
about 1-2 to 1'" in diameter (fig. 405).

Between the lobules run branches of the
vena portae, forming the interlobular veins
(coloured red in PI. 39. fig. 33) ; these
throughout their course send off numerous
smaller branches into the substance of the
lobules, which terminate in the capillary
plexus of the lobules.

The branches of the vena poilaj are accom-

LIVER.

Fig. 405,

[ 474 ]

Magnified about 3 diameters.

Portion of the liver of a pig, nith divided branches of
the vena cava ; the lobules are visible upon the divided
surfaces: a, large vein, no orifices of t lie intralobular
veins being visible ; fi, branches of the same, with dis-
tinct orifices of the intralobular veins, and the bases of
the lobules seen through their walls.

panied by branches of the hepatic duct and
ramilications of the hepatic artery, the whole
being surrounded by connective tissue pro-
longed from Glisson's capsule. Hence, in
a section of the uninjected liver,
those branches of the vena portge
and of the vena cava which ai-e
visible to the naked eye are readily
distinguishable from each other by
the orifices of the former collapsing,
whilst those of the latter are kept
open by their close contact with the
lobules.

In the centre of each lobiile arises
a branch of the vena cava, by the
imion of numerous smaller branches
(coloured yellow in PI. 39. fig. 33),
which take their origin in the ca-
pillary plexus of the lobule ; these
central branches form the intralobu-
lar veins.

The capillaries of the lobules form
a close and elegant plexus between
the branches of the inter- and intra-
lobular veins, the rest of the lobules
being filled up with the secreting
cells.

LIVER.

Fig 406.

Magnified about 4 diameters.

Section of the liver of a pig through a branch of the
vena portce, w ith accompanying branches of the hepatic
artery and duct. On the right are seen two branches
of the vena portse giving ofi the interlobular veins.

The branches of the biliary ducts accom-
pany those of the vena portse as far as the
interlobular spaces, where they again branch
off, forming a network of extremely slender
tubes or biliarv capillaries, which surround
individually the liver-cells (fig. 408). The
biliary ducts consist of an outer coat of
connective tissue, the bundles of fibres of

Fig. 407.

1

Section
course of
others

Magnified 35 diameters.

of a portion of the liver of a rabbit, showing the entire
one of the intralobular veins, the roots only of the

LIVER.

[ 475 ]

LIVEE.

■which are difficultly separable, and an in-
ternal epithelial layer. The former is most
distinct in the larger branches, being almost
absent in the terminal interlobular ducts ;
it contains numerous nuclei and nuclear
fibres. Kolatschewslij' states that the bile-
ducts are directly continuous Tvith the
cavity of the liver-cells. The epithelium

Fig. 408.

llagnifled 200 diameters.
Biliary capillarieB from the liver of the rabbit: a,
biliary capillaries; 6, liver-cells; c, bile-ducts ; <i, ca-
pillary blood-vessel.

of the larger ducts is cylindrical, that of
the smaller of the pavement kind. In the
hepatic ducts, the outer coat contains scat-
tered muscular fibre-cells. The ducts also
contain small mucus-glands. The secreting
cells of the lobules fill up the interspaces
between the blood-vessels. They are very
transparent, of a roimded or polygonal form,
about 1-1000" in diameter, containing one
or two nuclei, with a very fine reticulum
and a number of gi'anules, and a few small
globules of fat (fig. 160, page 238).

Kupffer describes star-cells existing with-
in the liver-ceUs, after staining with chlo-
ride of gold.

The division of the substance of the liver
into lobules is rather apparent than real,
being effected by the peculiar arrangement
of the vessels, the lobules having no true
coat or envelope.

The connective prolongation of Glisson's
capsule which accompanies the vena portae
and its branches becomes less and less in
quantity as the branches become smaller,
and is apparently lost in the interlobular
spaces. It is much more abundant in
animals, as the pig, than in man, rendering
the lobular arrangement much more dis-
tinct. But, after washing away the liver-
cells with a hair-pencil, from a thin section,
a very dehcate network, consisting of a
homogeneous membrane with minute nu-

clei, remains, in the meshes of which the
liver-cells are placed.

The branches of the hepatic artery are
distributed to the portal vessels, the hepatic
ducts, Glisson's capsule with its prolonga-
tions, and the peritoneal coat. They are
often elegantly tortuous.

Among the more common morbid states
of the liver may be mentioned: — that called
cirrhosis, in which the connective tissue is
excessively developed and mixed with a
large number of fibro-plastic corpuscles,
producing an atrophied state of the epithe-
lial structure ; the amyloid degeneration,
which commences between the inter- and
intra-lobular portions, in the branches of
the hepatic artery ; an increase in the
amount of fatty matter in the cells (fig. 160,
page 238) ; and the presence in these also
of granules of cholepyrrine, rarely with
crystals of cholesterine and bilifulvine.

The examination of the arrangement of
the blood-vessels is best made in a liver
which has been injected with two kinds of
injection, as yellow (chromate of lead) and
red (vermilion), or red and white (carbonate
of lead) — the yellow or white being injected
into the hepatic vein. As the injection is
being proceeded with, the surface of the
liver should be examined with a lens to
ascertain whether the intralobular veins are
well filled, and the injection has reached
the capillaries ; the red injection should
then be thrown into the portal vein until
it is filled. The general vascular arrange-
ment is best observed in an injection in
which the capillaries themselves are not
filled, but only the smaller portal and he-
patic branches.

To examine the ducts as to their course
and termination, the portal vein should
previously be injected. If this be not done,
the injection easily bursts through the walls
of the terminal ducts, and escapes into the
intralobular plexus ; and thus the appear-
ance of a plexus of vessels prolonged from
the terminal ducts is produced. The fine
ferridcyanide cold injection should be used.

The structure of the hepatic cells is easily
seen on scraping the surface of a section of
the liver, and placing the portion thus ob-
tained between two pieces of glass as usual.

The minute structure of the liver is best
seen in sections of portions which have
been hardened in chromic acid or spirit,
and stained with logwood. In these, the
cut orifices of the biliary capillaries are
sometimes seen, between the liver-cells.

LLAVEA.

[ 476 ]

LOPHOPUS.

The general arrangement of tbe secreting
cells is observed in sections made with
Valentin's knife.

In many animals, as fishes, the loading
of the cells of the liver with fat, which in
man represents the morbid state of fatty
degeneration, is normal, and renders it a
matter of some difficulty to distinguish
clearly the outlines of the cells, which are
also very delicate.

BiBL.' Kiernan, P/h7. Tr. 1833; KoUiker,
Mil-. Anatii.; H. Jones, Phil. Tr. 1846,
and 1840; Guillot, Ann. Sc. Nat. 1848;
Leidy, Sill. Jn. 1848 ; Beale, Liver, & Hoiv ;
Hering, Stn'cker^s Gewehel. i. 429 ; Kolats-
chewsky, Sch. Arch. 1877, xiii. 415 ; Frev,
Hist. 540.

LLA'VEA, Lagas. — A genus of Pteridese
(Polypodiaceous Ferns). One species ;
Mexico. (Hooker, Syn. Fil. 144.)

LOASA'CE.E.— A family of Dicotyledo-
nous Flowering plants, with stinging hairs
upon the epidermis. Loasa, Bartonia, and
Blumenhachia are often to be obtained in
gardens.

LOCUST-BEANS.— The seeds of Cera-
tonia siliqua are so called.

LOFTU'SIA, H. B. Brady.— A large fusi-
form arenaceous Foraminit'er, consisting of
a spiral lamina, secondary oblique longitu-
dinal septa, and tertiary vertical divisions,
making the internal structm-e labyrinthic.
In texture similar to the higher Trochcnn-
rnincp, Loftusia stands high amongst the
arenaceous forms, corresponding with Alveo-
lina in the Porcellaneous, and Fusidina in
the Hyaline group. Fossil in Persia.

BiBL. Brady, Phil. Trans. 1869, 751.

LOMA'RIA, AYilld.— A genus of Pteri-
deae (Polypodiaceous Ferns).

L. Spicant, often called Blechnnjn boreale,
is British. Many other foreign species.
(Hooker, St/n. 174.)

LONCH'I'TIS, PresL— a genus of Pteri-
dese (Polypodiaceous Ferns). Differs from
Pteris in the sori occupying the sinus ;
exotic (fig. 410). (Hook, 'Syn. 128),

Fig. 410.

Lonchitis pubesccnR. A pinnule with sori.

Maguifled 10 diani8.

LO'PHIUM, Fr.— A genus of Pyre-
nomycetes (Ascomycetous Fungi), remark-
ably distinguished by the form of the peri-
thecia resembling a bivalve shell with the
valves in situ (tigs. 411 & 412). The nu-
cleus contained within the carbonaceous

Fig. 411.

Fig. 412.

Fig. 413.

LophiuMi mytiliauiii.
Fig. 411. A perithecium, seen sidewise.
Fig. 412. The same, seen endwise.
Fig. 413. A perithecium cut open.

Magn. 2.5 diama.

perithecium consists of erect asci mixed
wdth paraphyses, containing minute spores,
and soon falling away into a powder. L.
mytiUnum, Pers. (figs. 411-13), occurs on
the bark or naked wood of fir trees. L.
datum, Carm., also occm's on fir wood.

BiBL. Berk. Br. Fl. ii. pt. 2. 280 ; Fries,
St/st. 31yc. ii. 633 ; Siimma Veg. 401 ; Gre-
ville, Sc. Cnipt. Fl. pi. 177.

LOPHOCO'LEA, Nees.— A genus of
Jungermannieee (Hepaticte), including J.
hidentata, L., and J. heterophylla, Schrad.,
growing in moist situations, at the roots of
trees, &c.

BiBL. Hook. Brit. Junyerm. pis. 30, 31
Br. Fl. ii. pt. 1. 122.

LOPHOxMONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Free, ovate, spherical or fusiform,
with an anteiior tuft of long slender
flagella.

Two species ; intestines of Blatta, &e.
(Kent, Inf. 321.)

LOPHOPPI'ORUS, Br.— A genus of
Copepodous Entomostraca.

L. indynis. In marine dredgings, Dur-
ham. (Biady, Copep.., Bai/ Sue. i. 121.)

LOPHOPO'DIUM, Ktz.-A doubtful
genus of Oscillatoriaceas, allied to Amphi-
thri.c. 6 spec, on submerged stones and
posts.

BiBL. Babenh. Fl. Fur. Aly. ii. 231.

LOPH'OPUS, Dutuortier.— A genus of
freshwater Polyzoa, of the order Hippo-
crepia, and family Plumatellida?.

Char. Polypidom sacciform, hyaline, ge-
latin lus, with a disk serving for attachment ;

LORICA.

[ 477 ]

LUNGS.

orifices scattered ; ova elliptical, with a
riiiii', but no spiues.

BiBL. Allman, Fresh. Poli/zoa (Hai/ Soc),
83 ; Johnston, £rit. Zooph. 391.

LORI'OA. See Carapace.

LOUSE. SeePEDicuLUSandANOPLtTRA.

LOVEXEL'LA, Hincks.— A genus of
Campanuliiriidaj (Ilydroid Zoophytes).

Char. Stems simple or slig-htly branching,
rooted by a throad-like stolon ; capsules
turbinate, elongate, operculum of distinct
segments ; proboscis large and prominent.
L. dausa, iu dredgiugs, Torbay.

BiBL. Hincks, ]3rit. Hyd. Zooph. 117 .

LOXOCEPH'ALUS, Eberh.— A genus
of holotriehous Infusoria.

Char. Free, ovate-oblong, constricted
towards the front, with one or more short
setfe at the constriction, and one or more
caudal setje.

Two species. Freshwater, with decaying
vegetation. (Kent, Inf. 488.)

LOXOCON'CHA, "Sars.— A marine Os-
tracode, allied to Cythere, with long setife-
rous antennte, and strong subrhomboidal
valves, which have toothed hinges and often
a pitted surfixce. Common in the British
and other seas, and fossil iu the Tertiary
and post-Tertiary strata.

BiBL. Bradv, Linn. Tr. xxvi. 432.

LOXO'DES, Ehr.— A genus of hypo-
trichous Infusoria, family Trachelina.

Char. Body curved, with a longitudinal
row of transparent vesicles, each of which
contains a highly refracting body, and with
a more or less arborescent distribution of
the digestive canal.

L. rostrum, Ehr., Pekcida rostrum, Duj.
(PI. 31. fig. 39); freshwater.

L. bursar ia (PI. 31. fig. 41) is a Parame-
cium. L. cuculluhis and L. dentatus belong
to Chilodon.

BiBL. Ehr. Inf. 323; Duj. Inf. 449;
Stein, Inf. ; Clap'arede et Lach. Inf. 339.

LOXOPIIYL'LUM, Duj.— A "genus of
holotriehous Infusoria, fam. Trachelina.

Char. Body flat and leaf-like; contractile
vesicle posterior, near the anus ; anterior
part of the bodv sometimes produced. 5
species. i./as«o/a (PL 30. fig. 10). They
belong to the genera Amphileptus and Tra-
chelius, Ehr.

BiBL. Duj . Infii.^. 487 ; Claparede et
Lachmann, jyifus.' 360 ; Kent, Inf. 527.

LOXOSO'-AiA, Keferst. — A genus of
Polyzoa, fam. Pedicellinidse. Like Pedi-
ce/lim, but united in colonies. 3 species,
on marine annelida. (Hincks, Polyz. 572.)

LOXSO'MA, Brown.— A genus of Hy-
menophylleiB (Polypodiaceous P'erns), dis-
tinguished by the projecting colunm bearing
the sporangia (tigs. 414^ 415, 410j.

Fig. 414.

Fig. 415.

Fig. 416.

Loxsoma Cunuinghamii.
Pig. 414. A pinnule with marginal sori. Magn.5 diams.
Fig. 415. A sorus opened. Magn. 2.5 diams.
Fig. 416. Columella with sporanges. Magn. 50 diams.

New Zealand (Hooker, Si/n. 56).

LUCERNARIA, Fabricius.— A genus of
Medusje. i. auricula is common in the
summer in the seas of England and Norway.
It can be kept for some time in an aqua-
rium, and from the small size of many indi-
viduals, is a very interesting object for the
microscope.

BiBL. M. -Edwards & Hainie, Coraill. iii.
457; Agassiz, Sea-side Stud., 1871, 46;
Keferstein, Zeit. f. iviss. Zool. xii.

LUMBRI'CUS.— A genus of setigerous
Aunulata. L. ten^estris, the earthworm.
Ray Lankester, Qu. Mic. Jn. 1864 & 1865 ;
Lockhart Clarke, Proc. Roy. Soc. 1857, 344
(nervous system) ; Rolleston, Forms of An.
Life.

LUNGS. — The internal respiratory sacs
of animals.

Under tliis head we shall notice also the
larynx, trachea, and bronchi.

Larynx. — The cartilages of the larynx do

LUNGS.

[ 478 ]

LUNGS.

not all possess the same minute structure.
The thyroid and cricoid cartilages consist of
hyaline cartilage, the basis being homoge-
neous, and containing disseminated cartilage-
corpuscles. The walls of the corpuscles are
usually thick. The basis often becomes
fibrous, and both corpuscles and basis in-
crusted with calcareous salts, or completely
ossified. Their perichondrium is firm, and
is composed of connective tissue, with fine
elastic fibres, vessels, and nerves.

The epiglottis (PL 49. fig. 40) and the
appendices of the arytenoid consist of fibro-
cartilage ; and the corpuscles are frequently
more or less filled up by secondary deposit.

The mucous membrane, as also the sub-
mucous tissue of the larynx, consists of
connective tissue with networks of fine
elastic fibres ; at the surface it becomes
more homogeneous, but does not form a
separable basement layer or membrane. It
contains a number of small racemose glands,
the vesicles of which are lined with pave-
ment, the ducts with cylindrical epithelium.
Its surface is covered with ciliated epi-
thelium, agreeing in structm-e with that of
the trachea.

Trachea and larger hronehi. — The incom-
plete cartilaginous rings of these tubes are
surrounded and connected together by a
iirm, elastic, fibrous membrane, forming
their perichondrium, which also covers the

Fig. 417.

V<^rA^y-

1^1

-■'mii

wm"

Epithelial cells of the trachea in sUu; human, a,
longitudinal elastic flbrea ; b, homogeneous outer (base-
ment) layer of the mucous membrane; c, deep layers
of round cells ; d, intermediate layers ; e, outer ciliated
cells.

Magn. 350 diameters.

posterior part of the tubes as a somewhat
thinner layer. The cartilage is of the true
kind. At the posterior part of the tubes is
a layer of unstriated muscular fibres, most
of w^hich form transverse, but a few longi-

Fig. 418.

tudinal bundles. The elastic tissue of the
mucous membrane is greatly developed,
forming a distinct internal layer of princi-
pally longitudinal anastomosing fibres.

The epithelium is ciHated, and consists
of several layers. The deepest layers are
composed of roundish cells with distinct
nuclei, those succeeding being elongated,
while those next the surface are still longer,
greatly nai-rowed at the base, and with oval
nuclei. Those of the last row are covered
wdth vibratile cilia (fig. 418).

The smaller bronchi differ
in structure somewhat from
the larger. Thus, the car-
tilage forms angular plates
distributed throughout
their circumference, while
the elastic and connective-
tissue coats become thin-
ner, and the transverse mus-
cular fibres smaller and less
closely placed.

Air-cells. The terminal
bronchi open into a group
of air-cells partly fused to-
gether, forming common
cavities — the lobules, al-
veoli, or infundibula. These
are separated from each
other by connective tissue
mixed with muscular
fibres, containing, in adult
animals, black pigment in ceflsfrom the surface
the form of granules, some- of the trachea ; hu
times also crystals. They
are best seen in the lungs
of young animals.

The walls of the pulmonary air-cells
consist of a fibrous, and an epithelial layer.
The former is composed of a basis of homo-
geneous connective tissue, with numerous
elastic fibres, vessels and nerves.

The elastic fibres surround the air-cells
in the form of elegant wavy bundles and
separate fibres, which anastomose and con-
stitute a dense network, most obvious at
those parts Avhere several cells are in con-
tact with each other ; while in other parts
the areolar element supporting the nume-
rous capillaries predominates, and the elastic
elements are more . sparing and slender.
The epithelium is of the pavement kind,
not ciliated, consisting of rounded or polygo-
nal nucleated cells, about ^jyVsj" in diameter.

The smaller or primary lobules are ag-
gi'egated to form larger secondary lobule-» —
the lobules of descriptive anatomists, and

Isolated epithelial

man.
Magnified 350 dia-
meters.

LUNGS.

[ 479 ]

LUNGS.

Fig. 419.

Two pulmonary lobules a a, with the air-cells 6 b,
and the terminations of the bronchi c c ; from an infant
newly born.

Magnified 25 diameters.

the outlioes of wliich in adults are also
principally mapped out by lines of pigment.

Fig. 420.

Outer surface of the lung of a cow, the air-cells of
which are injected with wax: a, a, a, air-cells; b, b,
boundaries of the (primary) lobules.

Magnified 30 diameters.

The lobular structure of tlie lungs is best
shown in the lungs of festal animals in-
jected from the trachea or bronchi.

The capillaries of the lungs are extremely
minute and very difficult to inject fully;
and the finest injection is required for the
purpose.

The capillaries may often be well seen
in thin sections of the inflated and dried
organs. The altered structure of emphyse-

matous lungs may also be best shown by
this method.

Fig. 421.

*.J^®

l^^-r^^V^

.>\:n^

Air-cells of a human lung, a, epithelium; 6, fibrous
portion, where the walls of several air-cells are con-
fluent ; c, thinner walls of several air-cells.

Magnified 350 diameters.

Fig. 422.

Capillaries of the human lung.

Magnified 60 diameters.

The epithelium is best seen in sections of

LUNULARIA.

[ 480 ]

LYCOPODIACE.E.

a luug wliich has been injected from the
trachea with a very weak solution of nitrate
of silver; or in well-washed sections treated
with very dilute acetic acid; solution of
logwood is useful for staining.

The lymphatics invest the subpleural
lobules in the form of a plexus, and dip
inwards to join the deep-seated tubes which
accompany the bi'onchi and large vessels to
the root of the lung.

In the lower vertebrate animals, the
structure of the hmgs is much simplar than
in the higher. Thus in the Triton each
forms a simple tubular sac, whilst in the
frog and toad (PI. 39. hg. 34) each lung
may be compared to a single lobule of a
lung of the Mammalia, having a cavity in
the centre, with which comparatively few
large cells extending into the periphery
communicate. The capillaries are also much
larger, especially in the two animals last
mentioned.

BiBL. Kcilliker, Mik. An. ii. ; Stannius,
Vergl. An. ; Waters, Human Lung., 1860 ;
Verson and Schulze, Strieker's Hist. i. ;
Williams, Tvdd's Cycl. An. ; Luschka, ^4?*-
chiv mik. Anat. v. 1 ; Frey, Hist., and the
Bibl.

LUNULA'PJA, Michel.— A genus of
Marchantiea}, growing on the ground in
shady places, having the perigones spread-
ing like rays from the top of the receptacle
(Hgs. 319, p. 387, 329-331, p. 389), which is
a mere peduncle, so that an approach is made
to the character of the Jungermanniese.
See Hepaticje.

LYCOG'ALA, Mich.— A genus of Myxo-
mycetes, consisting of somewhat globtdar
bodies, verrucose on the outside, composed

Fio-. 422*.

Lycogala epidendrum. Katural size.

Filament and spores of the same. M:asn. 200 diams.

of a double papery peridium, containing
capillitium and spores, growing on rotten

wood, &c. L. cpidench-um (fig. 422*) varies
from the size of a pea to that of a nut,
is globular when solitary, deformed when
growing in groups, and of a red colour. L.
parietinum is bluish black, and the peridia
do not exceed 1-20" in diameter.

Bibl. Berk. Br. Fl. ii. pt. 2. 307 ; Ann.
N. H. 2 ser. v. 365 : Grev. Sc. Crypt. Fl.
pi. 38; Fries, Syst. My col. iii. 79; Summ.
Veq. 448.

LYCOPER'DON, Mich.— A genus of
Trichogastres(GasteromycetousFungi). The
species are commonly known as puff-balls,
from the cellular matter being absorbed,
leaving the spores free, mixed with a few
threads, and discharged like a puff of smoke.
The structure of the hymenium is noticed
under Gasteromycetes; see also PI. 27.
fig. 6. The ignited mass of spores and
threads forms an anaesthetic.

LYCOPODIA'CE.^. — This order of
Cormophytous Flowerless Plants, Avhich
derives its name from the Lycopodia or
Club-mosses, is difficult to characterize in
general terms. The bifurcating branched
stem, rooting at each fork by a slender
thread-like adventitious root, and the ordi-
narily small overlapping leaves, distiugiush
most of the species of Zycopodium ; but
there is considerable variation from this
habit in the Psilotece, especially in Isoetes,
and the nature of the fructification is the
only mark generally applicable. The Ly-
copodiaceaj bear spores which are found in
small dehiscent cases at the bases of the

Fig. 423.

Fig. 424.

Lycopodium ©ayanum.

Fig. 423. Scale of spike with axillary sporange ; side

view.
Fig. 424. The same seen from the ontside.

Magnified 20 diameters.

leaves (figs. 423, 426, & 427), on the upper
face or imbedded in it ; and these fertile

LYCOrODlACE.^.

[ 481 ]

LYCOPODIACE.E.

leaves are either scattered all along- the
stem, or collected into spikes resembling, on

Fig. 425.

a small scale, elongated Pine-cones (figs. 425,
435). The plants of the genus Lycopodium
proper, exhibit both these conditions ; but

YiK. 420.

Fig. 427.

Lycop odium complanatum.
One third the natural size.

Fig. 428.

Selaginella cemua. Half natural size.

Selaginella apoda.

Fig. 426. Scale with oosporange. Magn. 20 diams.
Fig. 427. Scale with poUen-sporange. Magn. 20 dianis.

in all these the spores are small and nume-
rous and alike. In SelagincUa, to which
belong the elegant creeping Club-mosses,
with flattened leafy stems (often with a
metallic lustre), now so much grown in
Wardian cases (fig. 428), the capsular leaves
are in spikes, which are found forming one
arm of a bifurcation of the stem, while the
other continues the vegetative growth ; and
in the spikes we find the capsules on the
lowest scales (oosporant/es) producing only
fjur spores (macro -
spores, figs. 426, 429),
of much larger size
than tho.se (micro-
spores) contained in
large number in the
other spore-cases {pol~
len-sporanges, figs.
427, 430). In Lyco-
podium and Selaginella
the sporanges have but
one cavity ; in Tme-
sipferis the sporanges
are two-ceUed, and in
Psilotnm three-celled.
In Isoetes (fig. 376,
p. 443), where all the
leaves are seated on a
tuberous stem, and
most of them fertile,
the sporanges contain-
ing spores of each kind
are many-celled, and
immersed in the sub-
stance of the base9 of
the leaves.

2 I

LYCOPODIACE^.

[ 482 ]

LYCOPODIACE^.

Fig. 429.

Fiff. 430.

Selagiaella cernua. Half natural size.

Fig. 429. Oosporange with four large spores. Magn.

20 diams.
Fig, 430. Pollen-sporange burst, containing small

epores. Magn. 20 diams.

The anatomical structure of the stem of
the Lycopodiese is not very complex. There
is an outer thickish riud, composed of cel-
lular tissue ; and on cutting across a stem,
the ends of isolated tibro-vascular bundles
are sometimes seen traversing this; these
isolated bundles are merely a portion of
those forming a kind of cord running up
the centre of the stem, whence they have
been seen sent off to supply the leaves.
The fibro-vascular bundles are composed of
spiral-fibrous ducts siuTOunded by elongated

Fig. 431.

Fio-. 482.

Fig. 433.

,,e*i*SJ3e,

pP-

11

- - ■ •/

Lycoiiodium phlcgmarium.

Fig. 431. Section of the stem. Magnified 20 diameters.

Fig. 4:32. The centre of ditto. Magnified 100 diameters.

Fig. 433. One of the isolated bundles of ditto. Magnified 200 diameters.

Fig. 434.

Fig. 4.35.

Fig. 436.

Fig. 434. Lycopodium comnlanatum. Young shoot.

Fig. 43?. Lycopodium lufidulum. Spike of fruit. Mngnifled 3 diameters.

Fig. 436 Belaginella apoda. Young shoot. Magnified 2 ijlame.

LYCOrODIACE.E.

[ ^83 ]

LyCOPODlACE.E.

cellular tissue (see Tissues, vegetable),
which in lar^e woodj stems become ligni-
fied by secondaiT depo.^its. The roots have
also a central tibro-vas'jular cord, connected
with the central cord of the stem. The
structure of the little-developed tuberous
stem of Isoetes is very different, and ex-
hibits a remarkable mode of growth, form-
ing annual layers of woody structure (see

ISOF.TES).

The leaves are of very simple structure ;
but their arrangement exhibits many curious
peculiarities. In Psilotum, one of the
simplest forms, where they are mere minute
scales on a widely bifurcated stem, they
are alternate ; in some Lycapodia they are
opposite, in others whorled. When the
leaves are in whorls, they vary in number,
not only in different species, but often in the
same species in different localities, or even in
the same plant : thus, the arrangement is
often different on the main stem and ou the
branches.

When the leaves are opposite, those
forming the pairs sometimes differ both in
dimensions and form ; in Lijcopodlum cum-
planattim (hg. 434), the pairs of opposite
leaves cross alternately at right angles, so
as to form four rows up the stem ; in two
(opposite) rows the leaves are alike and
flattened laterally ; of the other two rows,
one consists of leaves like the two just
described, but flattened against the stem ;
and the fourth row (opposite the third) of
minute scale-like bodies. In other cases,
as in Selayinella apoda (flg. 436), the cor-
responding leaves of the pairs are unequal,
and are so an-anged that the smaller lie
in two contiguous vertical rows, on the
front of the stem. In most of the Lycopo-
diaceae the leaves are simple and almost
sessile ; but in Tmesipferis they have a blade
developed into two lobes and borne on a
long stalk ; and in Psilotum the short scale-
like leaf is also divided into two lobes and
supported on a petiole. The leaves of
Iscetes are different (see IsoiJXEs).

The reproduction of the Lyeopodiacete is
not uniform. In Lycopodiian the spores
are alike, producing monoecious prothallia ;
wliile in Selayinella and Isoetes, as above
stated, two kinds of spore exist, viz. micro-
spores and macrospores. It is found that
when both kinds of spore are sown, the
results of their germination are totally
distinct. The former small dust-like spores
burst their outer coat alter a time ; and the
delicate inner membrane, which is pro-

truded, likewise bursts subsequently and
discharges extremely minute eel's, in each
of which is developed an actively moving
spiral spermatozoid, like those of the Ferns.
This breaks out and swims about rapidly in
the water when seen beneath the microscope.
The large macrospore exhibits no external
change for a period varying from a few
weeks to a few months ; but a section
shows that a process of cell-formation has
commenced in its interior, which results in
the production of a kind of disk of cellular
tissue in the upper part, beneath that por-
tion of the outer spore-coat which exhibits
the three converging ridges produced by
the pre-sure of the four spores in the
parent sac during their development. At
this period the spore appears to have three
coats — an outer, tough, coloured coat, a
second coat lining this, and a third which
lines the second over the great cavity of the
spore, but at the upper part invests the
inside of the newly-formed disk of cellular
tissue, which thus lies between the second
and third coats. This disk of tissue is a
prothallium; and on its upper surface are
developed a number of archeyonia of very
simple structure. A cell of the substance
of the prothalliinn, taking on the function of
an emhryo-sac, develops a free cell {embryo-
cell) in its interior ; and the cells between
this and the surface become modified and
part, so as to leave an intercellular canal
between the contiguous angles of four ad-
joining cells, leading down to the embryo-
cell, — the four cells growing up from the
surface so as to form a kind of perforated
cellular papilla, something like that of the
archegone of the Ferns. At a certain stage
of this development, the outer coat of the
spore bursts at the converging ridges, and
the angular flaps resulting turn back and
expose the prothallium ou the upper surface.
One (sometimes two, but as an irregulaiity)
of the embryo-cells is then fertilized by the
spiral spermatozoids produced by the micro-
spores, if these exist at the right stage of
the development in the vicinity. After
this, the embryonal cell undergoes multi-
plication, flrst growing down as a cellular
fllament which breaks through into the
great cavity of the spore. The lower end
lying there then increases until it acquii-es
the form of a cellular nodule, which breaks
out above and exhibits on its free portion
the flrst adventitious root and the flrst pair
of leaves. The rootlet makes its waj- down-
waids into the soil ; and the leaves are

2i2

LYCOPODIE.E.

[ 484 ] LYMPHATIC SYSTEM.

gradually elevated on a thread-like stalk,
and separate, disi^laying two terminal buds
between them, whence the first bifurcation
of the stem proceeds.

Thismodeofreproductionallies the family
very closely to the double-spored JMarsi-
leaceas, and separates them from the Ferns
and Equisetaceat), in which the protliallium
is formed outside the spores, after the ger-
naination of the single and only kind of spore
which these plants possess. And by recent
authors, the Lj^copodiacese are separated
from the Selaginacese, on account of the
isosporous fructification of the one, and the
heterosporous fructification of the otlier.

The order Lycopodiacete is divided into
two families, in accordance with the struc-
tui-e of the sporanges :

Fmnilies.

Lycopodie^. Sporanges simple, one-
celled,

PsiLOTE^. Sporanges compound, many-
celled.

BiBL. Hofmeister, Verc/l. Unters. 1851,
111; De Bary, Ann. Sc. Nat. 4 ser. ix. 30,
An7t. N. H. 3 ser. iii. 189; Faukhauser,
Bot. Zeit. 1873; Strasburger, Bot. Zeit.
1873 ; Sachs, Bot. 474. See also Isof;tes.

LYCOPODIE'^E.— A family of Lycopo-
diaceous plants, distinguished by their
simple one-celled sporanges. The existing
kinds are all herbs, mostly creeping over the
ground ; but some of the fossil kinds, met
with especially in the Coal-measures, were
large trees, the Lepidodendra. Genera:

Lycopodium. Sporanges all of one kind,
containing numerous small spores resem-
bling pollen-grains.

SeUir/inella. Sporanges of two kinds, the
greater part resembling those of Lycopo-
dium ; one, situated at the base of the spikes,
larger, often four-lobed, and containing only
four large spores.

LYCOPO'DIUM, Linn.— A genus of Ly-
copodieae. This has been sufficiently cha-
racterized under the head of Lycop(>diace8e.
There are more than half-a-dozen British
species, mostly alpine plants ; but L. inirn-
datmn occurs on bogs in all parts of Britain.

BiBL. Hook, Br. Ft. ; JBabinglon, Bi-.
Bot. ; Francis, Br. Ferns^ 8ic. See also

LYCOPODIACEiE.

LY'GEUM, Linn. — A genus of Grami-
naceaj ; L. spartum is Esparto-grass.

LYGO'DIUM, Swarlz.— Agenus of Schi-
zasaceie (Polypodiaccous Ferns), consisting
of beautifid climbing plants, with conju-

gate, palmate, lobed, or pinnate leaves,
having the sessile sporanges in double rows
on the teeth of the pinnules (fig. 437), each

Fig. 437.

Lygodium retieulatum.
Portion of a leaf, with fertile pinnules. Nat. size.

having a hood-like special indusium ffia'S.
438,439). °

16 sp. ; tropical. (Hook, Syn, 437.)

Fij?. 438.

Fig. 439.

Lygoclium retieulatum.

Fig. 43S. Tooth of a pinnule with overlapping indusia.

Magn. 2U diams.
Fig. 439. The same, with the indusia removed to show
the sporanges. Magn. 20 diams.

LYMPHATIC SYSTEM.— This consists
of the lymphatic or absorbent vessels, and
the lymphatic glands.

The lymphatic capillaries commence in
the various tissues and organs, as fine net-
works or irregular lacunoe. The lacunse are
connected by canals and clefts, and form a
h'mph-canalicular system. The Ivmphatics
of the intestines — the lacteals, commence as
cseca.

In structure the lymphatics resemble the
veins, but the walls are thinner in propor-
tion to their calibre ; they are also fur-
nished with valves, formed by folds of the
inner and epithelial coats.

Tlie Ivmpliatic capillaries are larger tlian
the blood-capillaries. At the surface of the
serous membranes, the lymphatics are cun-

LYMPHATIC SYSTEM.

[ 485 ]

LYNGBYA.

I

nected with small openings left between the
epithelial cells, called stomata ; so that the
serous cavities and the lymphatic system are
directly continuous. The lymphatics in
their onward course unite, passing through
the lymphatic glands, forming longer ves-
sels, ultimately terminating by two trunks,
one of which is the longest and called the
thoracic duct, and which terminate in the
angle formed by the internal jugular and
subclavian veins on each side.

The lymphatic or conglobate glands con-
sist of a capsule, composed of connective
tissue with scattered tine elastic fibres, and
in animals unstriated muscular fibres. The
substance of the glands consists of a cortical
and a medullary portion.

The cortical portion, which in the larger
glands forms a layer about 1-0 to 1-4" in
thickness, exhibits a coarsely granular ap-
pearance, visible externally through the
capsule. This arises from the presence of a
large number of septa or trabeculje pro-
longed from the capsule into the substance
of the organ, and dividing it into alveoli ;
these are about 1-96 to 1-36" in diameter,
and of a rounded or polygonal form ; they
are more distinct in animals than in man.
The septa consist of connective tissue with a
few tine elastic fibres, and numerous delicate
spindle-shaped bodies, often anastomosing
at their ends.

The contents of the alveoli are greyish
white, pulpy, traversed by capillary blood-
vessels, and by numerous delicate hbres,
with spindle-shaped and stellate cells re-
sembling those found in the septa, but form-
ing a lacunar or spongy adenoid tissue.
The soft substance consists of free nuclei
and rounded cells, resembling those foimd
in the chyle and lymph.

In the medullary portion, the retiform
tissue is very fine, closely filled with lymph-
corpuscles, and connected with a plexus of
lymphatics, ending in the efferent vessels.

The afferent vessels penetrate the capsule,
pass through the septa between the alveoli,
and open into their lacuuc-e, which are not
lined with epithelium. From these, the
lymphatics of the medullary plexus arise,
to terminate in the eiferent vessels.

The course of the lymph is from the
afferent vessels into the capsular network,
thence into the cortical and the medullary
sinuses ; from these into the network of
lymphatics of the hilus, and finally into the
efferent lymphatic vessels.

The injection of the lymphatics is a very

difficult matter. Partial injections may be
obtained by injecting the prussian-blue
lictuid into an aperture made in the dif-
ferent tissues or organs. The structure of
the glands is made out, in ordinary sections
well washed to remove the lymph-corpus-
cles. See on these matters, Rutherford's
little ' Practical Histology.'

The lymph, or liquid contained in the
ordinary lymphatics agrees essentially with
the chyle, except that the molecular base is
absent ; the white corpuscles forming the
characteristic microscopic elements. These
are described at p. 101.

Lymphatics in Amphibia, — The structure
and arrangement of the larger lymphatics
differ in the Amphibia. They do not form
cyhndrical tubes, but lacunae, which occupy
the interspaces between the different organs,
the surface turned towards the interior of a
cavity being covered with a single layer of
tessellated epithehum. These cavities or
sacs communicate with each other by means
of microscopic openings. As there are no
contractile tissues in the walls of the sacs
special contractile organs acting rhythmi-
cally, or lymph-hearts, are superadded. A
very visible one in the frog is close to the
sacrum, and pnmps the lymph into the
sciatic vein ; another propels it into the
jugular. They are chietiy composed of
transversely striated short muscular laminae.

BiBL, Kolliker, Mik. Anat. ii. ; Todd &
Bowman, Phi/s. An. ii. ; Lane, Todd's CycL;
Teichmann, D. Saugad., 1862 ; Briicke, Sitz.
Wien. Akacl. 1852-18/)5 ; His, Zeits. iviss.
Zool. xi., xii.,xiii. ; Recklinghausen, Stnclcer''s
Hist, i.; E. Klein, Lxjmph. Si/st., 1873; Sap-
liej,An.Si-Pht/s. d.vaiss. lymi?h., 1876; Frey,
Hist. 1876, and the lit.
_ LYNG'BYA, Ag.— A genus of Oscillato-
riacese (Confervoid Algas), related to Culo-
thrix and OsciUatoria, distinguished from
the former by its stratiffed habit, from the
latter by the long flexile but not oscillating
filaments. It contains both freshwater and
marine species. L. muralis (PI. 8. fig. 10)
grows in damp places and in water. The
specific characters are not satisfactory; but
we have found what we take to be L.
siagnina, Kiitz. Tab. Phyc. i. pi. 87. fig. 5,
and L. concinnata, KiiJ:z. I. e. pi. 89. fig. 5,
in fresh water. L. speciosa, Cannichaelii,
and ferruqinea, marine species, are figured
in Engl. Bot. Supp. Nos. 2926-27 a and h.

These plants appear to break up into lenti-
cular gonidia ; but their reproduction, like
that of OsciUatoria, is very obscure.

LYSIGONIUM.

[ 486 ]

MACROSPORIUM.

Braxton Hicks has stated that L. muralis,
a Sc/nz'iffo?imm, and a Prasiola are all dif-
ferent stages of the same organism, and has
noticed the segmentation of their gouidia
into Palmelloid cells.

BiBL. Hassall, Brit. Fr. Ajg. p. 219,
pis. 59, 60, 72; Harvey, Brit. Mar. Alg.
p. 22o, pi. 26 E. ; Kiitz'. Sjkc. Alq. p. 279 ;
Tub. Phi/c. i. pi. 86-90; Rabenh. Fl. Eur.
Alg. ii. 135 ; B. Hicks, Qu. Mic. Jn. 1861.

LYSIGO'NIUM. SeeMELOsiBA.

M.

]\rACERATION.— The soaking of ob-
jects in various menstrua, for the purpose
of causing decomposition and solution of
portions of structure which are more readily
attacked, is an operation frequently had
recourse to in the anatomy both of animals
and plants. In addition to water, cold and
hot, a number of stronger agents are often
employed, chiefly oxidizing substances, such
as Nitric Acid, the same combined with
chlorate of potash, &c. Ammonio-oxide of
copper dissolves delicate cellidose rapidly,
and does not so soon attack woody fibre,
&c. See Tissues.

MACHI'LIS, Latr. See Petbobitjs.

MACROBIOTUS, Schuhze.— A genus
of Tardigrada (Arachnida), family Arctisca.

Char. Head not furnished with append-
ages ; mouth terminated by a sucker, with-
out palps ; skin soft, with irregular ruga3.

M. Hufelandxi (PI. 50. fig. 8). Body
cylindrical, colourless ; head rounded in
front, with minute coloured eye-spots ;
sucker, pharyngeal tube, and styles well
developed ; oesophageal bulb supported by
a sohd frame- work of jointed pieces; legs
equal ; claws two, bifid, the poi'it of each
aorain bifid ; movement tolerably quick ;
sFze 1-85 to 1-35".

The most common species ; found upon
mosses growing on walls, stones, at the foot
of trees, &c.

M. Oberhduseri. Dark brown ; colour
distributed unsymmetrically in spots, and
forming five longitudinal bands ; no eye-
spots ; claws three, — one simple, terminal,
and forming a short filament ; the two
others hooked, the interior one double or
bifid, the posterior simple ; movement very
active ; length 1-100 to 1-85".

M. ursellus. Claws three, none fila-
mentous.

M. Dujardinii. Claws two, bifid.

BiBL. Doyere, Ann. Sc. Nat. 2 ser. xiy.,
xvii. and xviii. ; Dujardin, ibid. x.

MACROCY'PRIS, Brady.— An Ostra-
code, aUied to Bairdia, among the Cypridce,
with long, smooth, pointed valves, and
characterized by short setae on the upper
antennae and rudimentary postabdominal
rami. Living in the North Sea (M. mimia,
Baird); fossil in the Chalk (J/, siliqua,
Jones).

BiBL. G. S. Brady, Limi. Tr. xxvi. 391.

MACROGONIDIA.— A name applied to
the larger form of ciliated zoospore found
in many Confervoid Algte, associated with
a form much smaller, distinguished as
MicROGO>;iDiA. See Zoospores and Hy-

DEODICTYON.

MACROSPORES, or MEGASPORES.

See Spores.

MAC'ROSPO'RIUM, Fr.— A supposed
genus of Dematiei (Hyphomycetous Eungij,
growing upon decaying vegetable matters,
corresponding to Sejjtosporimu , Corda, and
Hebnisporium, Duby. Several species are
British. M. Cheirnnthi, Fr., is common on
wallflowers and stocks ; M. BrassiccB, Berk.,
on cabbage-leaves ; M. sarcinula, on gourds;
and M. concinnum, on rotting decorticated
willow twigs. We have found one species
among the Oidium of the vine-fungus.

Fig. 440.

Macrosporium bulbotrichmn.
Magnified 200 diams.

Tulasne shows that they are conidiiferous
forms of a Sphseriaceous genus. The spores
of different species of Macrosporium were a
very prominent feature in the organisms
observed in deposits from the air at Cal-
cutta.

BiBL. Berk. Br. Fl. ii. pt. 2. 339 ; Ann.
N. II. i. 261, pi. 8. fig. 10, vi. 435, pi. 12.
fig. 21 ; Fries, Sinnma Veget. 501 ; Sgd.
Mgcol. iii. 274 ; Corda, Ic. Fung. i. 175,
176, 188 ; Tulasne, Ann. Sc. Xat. 4 ser.

MACROTHRTX.

[ 487 J

MAIZE.

V. 109; Cunningham, Mic. Exam, of Air,
C'tlcutta, 1873.

MAC'KOTHRIX, Baird.— A genus of
Eutomostraca, of the order Cladocera and
family Da]]hniad£e.

Char. Five pairs of legs ; beak directed
forwards; superior antennae of considerable
size, one-jointed, and pendnlous from the
beak ; inferior antennre two-branched, pos-
terior branch four-, anterior three-jdiuted,
and with a ver}- long tilament arising from
the end of the first joint ; a black spot at
the root of the superior antenuiB.

M. laticornis (PI. 19. tig. 2o). Shell
oval, smooth, anterior margin strongly
ciliated ; eve areolar.

Found in ponds.
M. rose us. Eve

superior antennfe longer

areola ;
slender

Found

without an
and more
than in the above

Probably a variety of the last,
in Scotland.

BiBL. Baird, £r. Enfom. 10-3; Norman
& Brady, Mail., Nat. Hist. Tr. Nortlmmb.

MADOTHE'CA, Bu- Yi^. 441.
mortier (Jungermnnnia,
L.). — A genus of ,lun-
germanniei'B (Hepaticse),
containing two British
species :— one, M. platy-
phylla (fig. 441), com-
mon on walls, rocks, and
trees ; the other, M. Ice-
tigata, found on alpine
rocks. The sporange is
borne on a short stalk,
globose, and bursts by
four convex valves, from
which the elaters are
quite free. The globose
persistent epigone is seen

in the fio-ure inside the Madothecaplatyphylla.
, 1 • J • Magn. o diams.

two-hpped penaone.

BiBL. Eudl. ^Gen. Plant. Siqjpl. i. 1.341 ;
Hooker, Br. Fl. ii. 125, Brit, jimgermann.
pis. 35, 40, and Supp. pi. 3 ; Ekart, Synops.
Jimqerm. 52, pi. 3. tig. 24, pi. 0. fig. 44.

MAGNESIA, Salts of.

Ammonio-phosphate of magnesia or triple
phosphate. This salt is frequently met with
an animal secretions which have undergone
decomposition, also in calculi. The most
common forms are prismatic, and figured in
the group a, b, PI. 13. fig. 1 ; but their va-
rieties are endless. Those of the above
group are frequent in decomposing urine,
blood, fteces, &c. Those in group c are
occasional in urine. Those of group d are

found in the contents of the vesiculae semi-
nales. The forms e and /are rare. Fig. 2
a, b, represents the so-called penniform
crystals, or rather groups of crystals (prisms)
occasionally found in urine. Fig. 3 repre-
sents the stellate form, occasionally found
in urine; sometimes the minute and imper-
fectly formed crystals of fig. 4 are met with
in the same liquid.

The crystals belong to the rhombic system.
The prismatic crystals were formerly re-
garded as consisting of a neutral, and the
feathery of a bibasic salt ; but the composi-
tion of the two is the same, and the variation
in form depends upon the conditions under
which they are produced.

The prismatic forms may be prepared by
allowing urine to decompose spontaneously,
or by diluting this secretion with water and
gi'adually stirring-in very dilute solution of
ammonia in small quantities at a time ; the
penniform crystals by adding excess of solu-
tion of ammonia to very dilute solutions of
the phosphate of ammonia and sulphate of
magnesia ; and the feathery forms by adding
excess of ammonia to urine. The prismatic
crystals form a beautiful polarizing object.

Sulphate of magnesia (Epsom salt). When
crystallized upon a slide from an aqueous
solution, the prisms of this salt, mounted
in balsam, form an interesting polarizing
object; they are also analytic.

Borate of magnesia fused into a bead
before the blowpipe is a beautiful object
(Sorby).

Urate of magnesia. See Ueic Acid.

BiBL. That of CHEinsTRY, and Phil. Mag.
1852, iii. 378.

MAG'NETITE. See Rocks.

MAGNIFYING POWER. See Mea-
surement.

MAGOSPHtERA, Haeckel.— a genus of
Catallacta (Protista) ; according to Kent, a
Flagellate Infusorian.

BiBL. Haeckel, Jenai. Zeit. 1870 ; Kent,
Inf. 323.

"MAHOGANY.— The wood of various
species of Stvietehia (Nat. Ord. Cedrelaceas).
Cross sections of this well-known wood
form good objects for showing the structure
of Wood with low power.

MAIZE. — Indian, corn, Zea Mays, L. —
One of the family of Grasses producing
seeds used as corn. The seeds, or rather
caryopses, are remarkably firm, being of a
horny texture in the outer part of the sub-
stance, while the central mass is more or
less brittle and soft. The solidity of tho

MALLOMONAS.

[ 488 ]

MARCH AN TIA.

grain results from the outer cells of the
albumen being densely filled with starch-
grains (PI. 40. fig. 3), which, by pressure,
assume a parenchymatous form and cohere
together firmly. In the centre they are
loosely packed in the cells, and then are of
rounded forms (figs. 5 & 6). Figs. 1 to 4
represent successive stages of development
of the starch-grains in the protoplasmic
mass originally filling the cells, but finally
almost wholly displaced. See Starch.

MALLO'MONAS, Perty.— A genus of
Ciho-flagellate Infusoria.

Char. Body oval, elliptic or discoid, with
brown or greenish contents; surface covered
with long non-vibratile hairs ; a single long
anterior llagellum.

2 species ; marsh-water.

BiBL. Pertv, Inf. 170 ; Kent, Inf. 464.

MALPIGHIAN BODIES. See Kidney.

MANDIOC or MANIHOT. See Cassava.

MANILLA HEMP.— One of the most
delicate of vegetable fibres used for textile
fabrics, yielded by the liber of the fibro-
vascular bundles of Musa te.vtilis, a kind of
banana common in the Philippine Islands
(PI. 28. fig. 7). It is manufactured into
"Manilla handkerchiefs" and "Manilla
scarfs," consisting of a delicate muslin.
These are often erroneously stated to be
made of the fibre of some kind of Pine-
apple. See Textile Substances.

BiBL. Hool-er's Journ. Bot. 1849, i. 28.

MARANTACE^.— A family of Mono-
cotyledonous Flowering plants, to which
belong the true West-Indian arrow-root
plants (see Arrow-Root), and the Tous-
les-niois plants, species of Canna. These
substances consist of the starch (PI. 46.
figs. 18, 25, & 26) obtained from the tube-
rous rhizomes of the plants (see Starch).

MARATTIA, Swartz.— The typical ge-

Fig. 442.

Fiff. 443.

Marattia.
Fig. 442. Side -^-iow of a sorua.
Fig. 443. Inclusium with the
sorus removed.
Magnifled 12 diams.

mis of Mavattiaceous Ferns. Tropical (figs.
442 & 443). Hook, Syn. 440.

MARATTIA 'CE^.— An order of Ferns,
approaching the Polypodiacese in general

habit, but more resembling the Ophioglos-
saceEe in their sporanges, which are destitute
of an annulus, and often so fused together
as to form a midtilocidar sac. Gen. :

Anf/iopfo'is. Caps, very close together,
opening by a lateral slit.

Marattia. Capsules concrete, opening
by internal slits.

Dancea. Caps, concrete, opening by api-
cal pores.

Kaidfussia. Caps, concrete, in raised
circular masses, openings internal.

MARBLE. See Rocks.

MARCHAN'TIA, Micheli.— A genus of
Marchantiefe (Hepaticfe), Liverworts. The
most common species is M. j)olynior])hn.
It is a little plant, not uncommon upon the
earth of damp shady courtyards, the borders
of springs, &c., extending itself in bright-
green thin lamellae of irregular lobed outline,
attached to the soil by radical hairs arising
on the lower surface. The frond presents
an upper and lower epidermis, with an
intermediate parenchyma ; and the lobes
are traversed by a kind of midrib. The
upper surface is marked by raised lines
which cross each other very regularly,
leaving between them lozenge-shaped spaces
(fig. 444), in the centre of each of which

Fig. 444.

Marehantia polymorpha. •

Lobe of a frond.
Magnifled 10 diameters.

occursa stoma, leading to an intercellular
space in the parenchyma. The stomata of
Marchantia are circular, and consist of six-
teen cells, an-anged so as to form four rino-s,
one upon another, each ring being composed
of four cells ; they may be best explained
by comparing them with a chimney com-
posed of four courses of bricks, each con-
sisting of four bricks laid together to enclose
a square. The parenchyma is composed of

MARCIIANTIA.

[ 489 ]

MARCIIANTIA.

several layers of cells, which contain much
chlorophyll. The inferior epidermis is
clothed with radical hairs, whicli exhibit a
remarkable spiral inarldug, arising from the

f)rojection of a --spirally deposited secondary
aver in the interior of the tube.

The fi'onds do not readily develop spo-
ranges in shady places; but when exposed to
the" light, they are produced at the ends of
the ribs, at the base of the terminal notches

Fig. 445.

Mareliiintia polymorpha.

Plant with antheridial receptacles (male).

Nat. size.

of the lobes. The male structures are pro-
duced on different plants from the female ;
but both are borne on peculiar stalked re-
ceptacles. The first appearance of one of
these receptacles is as a little green papilla
surrounded by reddish scales, at the end of
one of the principal ribs. As it enlarges, it
pushes its way through the scales ; and the
rib on which it is borne elongates to form
a pedicel, on which it is raised up perpen-
dicularly above the surface of the frond,

Fig. 446.

Marcliantia polymorpha.

Plant with fertile receptacles (female).

Nat. size.

ultimately acquiring the form of an ex-
panded cap. In the male receptacles it has
a sinuate margin (tig.44o) ; and in the female
the border is developed into eight or nine
thick cylindrical lobes (fig. 446).

The male receptacle is concave above,
with papillae consisting of the mouths of
flask- shaped cavities, in each of which is
formed an antheridium (fig. 447). These

Fig. 447.

Marcliantia polymorpha.

Section through an antheridial receptacle, showing

flask-shaped cavities containing the antheridia.

Magnified 25 diameters.

antheridia are oval cellular bodies lodged in
the expansion of the cavity, with a long
neck projecting upward through the mouth
of the flask-shaped excavation. The cells
of the interior of the lower part of the an-
theridia produce spermatozoids (PI. 40. fig.
32). The lower surface of the receptacle is
clothed with membranous processes and
hairs.

The female receptacles are somewhat

Fig. 448.

Marchantia polymorpha.

A sporangial receptacle seen from below.

Magnified 5 diameters.

MARCHANTIA.

[ 490 ]

MARCHANTIA.

convex above ; and on the under surface of
the base of each lobe are found delicate
membranous processes with toothed mar-
gins. The membranes of each two adjoin-
ing lobes form a perichcetium (fig. 448)
alternating with the lobes, concealing be-
tween them the archeyonia, which are at-
tached by their bases, and have their mouths
pointing downwards. The archegones of

ring surrounding
ultimately rising

it (fig,
up so as

Fig. 448'

Marchuntia polymorpha.

Archegonia in yarious stages.

Magnified 100 diameters.

Marchantia are flask-shaped sacs with a
long slender neck (fig. 448*), containing
in their cavity a cell (germ-cell), which
after fertilization becomes developed into an
oval cellular body, the young sporan(/ium.
In the course of the development of this, it
soon fills the cavity of the archegone, which
then begins to grow with it, and subse-
quently forms a loose sac around it — the
ejnffonium — finally ruptured at the point, so
as to exhibit four or five teeth or valves,
which become recurved (fig. 449). Mean-
Fig. 449.

Marchantia pol3nnorpha.
Vertical section of Fig;. 448, showing sporanges in situ,
bursting to discharge the spores and elaters.

Magnified 10 diameters.

while another envelope grows up around
the epigone, appearing at first as a mere

448*), but
to enclose it,
remammg open however at the summit ;
this is the perigoniu^n. In its young stages
the sporange is a mere oval mass of poly-
gonal cells ; but a distinction may soon be
detected between a cortical or peripheral
layer and the internal mass. The cells of
the former remain firmly united into a
membrane forming the wall of the sporange.
These cells grow so as to assume an elongated
form, and when mature exhibit internally a
spiral-fibrous secondary deposit (PI. 40. fig.
35), analogous to that of the cells of the
anthers of Flowering plants. The cells of
the internal mass present at an early period
the appearance of a large number of fila-
ments radiating from the centre
sporange to the wall. These soon
free from each other ; and it may
perceived that some are of very
diameter, and others three or four times as
thick. The slender ones are developed at
once into the long elaters (PI. 40. fig. .36)
characteristic of this genus, containing a
double spiral fibre, the two fibres, however,
coalescing into one at the ends (fig. 37).
The thicker filaments become subdivided by
cross partitions, and break up into squarish
free cells, which are the parent cells of the
spores, four of which are produced in each
(PI. 47. figs. 10-13). The spores of M. po-
lymorpha have but a single coat ; and their
contents are bright yellow when mature.
When they germinate, the contents are
converted into chlorophyll ; and the groAvth
commences by the production of a tubular
process from one side of the spore.

Fig. 450.

of the
become
then be
slender

A collection of gemmae in their involucre.
Magnified 25 diameters.

It lias been mentioned that M. polymorpha
does not fruit freelv in the shade. Under

MARCHANTIE.E.

[ 491 ]

MARSILEACEyE.

these circumstances it produces gemmce,
consisting of little, compressed, oblong
masses of cells, of green colour, capable of
reproducing the plant. These are found,
■when mature, in elegant cup-like struc-
tures, with toothed borders, sessile on the
upper face of the frond (tigs. 446, 450).
The cup seems to be formed by a develop-
ment of the superior epidermis, which is
raised up and tinally bursts and spreads
out, laying bare the gemmae, produced from
the internal parenchyma. The gemmae
consist at first of a single cell, which di-
vides so as to present an upper and a lower
(stalk-) cell ; the upper multiplies until it
becomes a cellular mass (fig. 451). The

Fig. 451.

Marchantia poljrmorpha.

A Tertical section of the same, with nascent gemmsB.

Magnified 50 diameters.

development of this structure presents much
analogy to that of the sori of the Ferns with
their iudusia and sporanges.

The Marchantice also increase by innova-
tions, or lobes of the frond becoming de-
tached from those on which they originate.

These plants form most interesting ob-
jects of microscopic investigation, in all
parts of their structure.

BiBL. Hook. Br. Fl. ii. pt. 1. 105 ; Engl
Bot. pi. 110; Mirbelj Mem. Acad. Paris,
xiii. 337, 375 ; Niigeli, Linna-a, xvi. 1842 ;
Henfrey, Dev. of Spores ^r., Linn. Tr. xx.
103, pi. 11; Thuret, Antheridies, Ann. Sc.
Nat. 3 ser. xvi. 72, pi. 12 ; Gottsche, Bot.
Zeit. 1858, Swppl. ; Strassburger, Jahr. wiss.
Bot. vii. 409 ; Sachs, Bot. 354.

MARCHANTrE^.— A family of Liver-
worts or Hepaticae. — Brit. Genera : Mar-
chantia, Fef/ateUa, Behouillia, Lunularia.
See Hepatic.^.

MARG ARIC ACID and MARGARINE.
— The former general ingredient of the fatty
matters of both the animal and vegetable
kingdom, when crystallized from hot alco-
hol, forms minute needles, either isolated

or in groups (PI. 11. fig. 16 a). The crys-
tals differ from tliose of stearic acid, which
form lanceolate single or aggregated plates
(PI. 11. fig. 16).

Margarine crystallizes from a hot alcoholic
solution in fine needles, mostly grouped or
branched, sometimes surrounding globules
of oleine, or forming bulb-like aggregations
of needles (PI. 11. fig. 15). It is sometimes
found crvstallized within the cells of fatty
tissue (I>1. 11. fig. 15 a)

Margaric acid is now
ture of

regarded as a mix
stearic

acids, and
these acids

-A Nodosa-
equi lateral,

palmitic and

a combination of
with glycerine.

BiBL. That of Chemistry.

MARGIN ULI'N A, D'Orb.-
rine Foraminifer, elongate,
curved or spiral in its earlier portion ;
chambers globular or compressed ; orifice
rounded, marginal. Kodosaria raphanus
becomes Marginuline with an eccentric
aperture (PI. 23. figs. 30-32); and, by gradual
modifications, Marginulina passes into Cris-
tellaria, with which ^\'illiamson unites it.

Common in existing seas ; and fossil from
the Trias upwards.

BiBL. Williamson, i?ec. For am. Z^; Mor-
ris, Br. Foss. 37 ; Parker & Jones, Ann.
N. H. 3. xii. 432; Carpenter, Intr. For.

MARSIL'EA, L.— A genus of Marsilea-
cete (Flowerless Plants), growing in mud,
by a creeping rhizome, from which arise
erect filiform leaf-stalks, supporting a com-
pound fom'-lobed blade ; at the bases of the
leaf-stalks arise also stalked capsules, cham-
bered in the interior, being divided by one
perpendicular and many horizontal septa ;
in these chambers are found sacs (sporanges)
containing the spores. This plant agrees in
all essential respects with Pilulaeia. See
Mahsileace^.

MARSILEA'CE/E.—Afamily of Flower-
less plants possessing a slight leafy stem ;
composed of a small number of plants, of
minute dimensions, but of gi'eat interest in
a physiological point of view. They are all
aquatics, some growing in the mud in and
around ponds, others floating on the surface
of stagnant waters. They all bear distinct
spore-fi-uits or sporocarps, seated on a stalk
arising from the stem. These contain spo-
ranges or spore-sacs, differently arranged in
the different genera, but agreeing in this
respect, that they ccntain spores of two
kinds, macrospores and microsporus, aualo-

MARSIPELLA,

[ 492 J

MASTOGONIA,

gous to the two kinds of spore in Lycopodi-
acese, bat differing in their mode of develop-
ment.

Pilularia (jlohuJifera is the only British
representative of this ftimil}'.

BiBL. Hofmeister, Venjl. Writers. 103,
pis. 21 & 22 ; Henfrey, Tr. Br. Assoc. 1851 ;
Ann. N. H. 2 ser. ix. 447 ; Hanstein, Mo-
natsh. Ak. Berlin, 1864, Ann. N. H. 1864 ;
Sachs, £o(^.444(tij?.).

MARSIPEL'LA, Norm.— A delicate are-
naceous Foramiuifer, related to Astrorhiza.
(Norman, Ann. N. H. 5. i. 281 ; Brady, Qu.
Mic. Jn. xix. 17.)

MARY'NA, Griiher.— A genus of Holo-
trichous Infusoria. Bodies cup-shaped,
with a funnel-shaped cleft neck : terminal
on the ends of a branched zoary. M. socialis,
marine (Kent, Inf. 520.).

MASTIGAMCE'BA, Schulze.— A genus
of Flagellate Infusoria.

Char. Amojba-like, changeable, creeping,
emitting pseudopodia, with an anterior fla-
gellum. Four species ; freshwater. M.
aspera (PI. 53. fig. 22). (Kent, Inf. 221.)

M ASTIGOB 'RYUM. See Herpetium.

MASTIGOCER'CA, Ehr.— A genus of
Rotatoria, of the family Euchlanidota.

Char. Eye single and cervical ; tail-like
foot styliform; carapace prismatic, with a
dorsal crest.

M. carinata (PI. 43. fig. 46, side view).
Foot as long as the body ; freshwater ; entire
length 1-72".

BiBL. Ehrenberg, Infiis. p. 460.

MASTIGOC'LADUS, Cohn.— A genus
of Confervoid Algse, allied to Sirosiphon.

Char. Filaments moniliform, dichoto-
mously ramose, without sheaths. Secondary
branches with cylindrical cells, among
which are some elliptical ; foi-ms a fleshy,
spongy layer.

M.^laminosus (PL 52. fig. 9), in warm
springs.

BiBL. Rabenh. FL Eur. Air,, ii. 284.

MASTIGONE'MA, Schwabe.— A genus
of Rivulariacese.

Char. Filaments tufted, articulated, elon-
gate, with thin ends, sheathed ; apex of the
sheath open. M. }}lana, an Irish and Scot-
tish species.

BiBL. Rabenh. Fl. Eur. Air,, ii. 226.

M ASTIGOPII'ORA, Hincks,= iep-a//a
pt. (Hincks, Volyz. 278).

MASTIGO'TliRIX, Kiitz.— A genus of
Rivulariaceae.

Char. Filament single, bent, fiagelliforra,

ending in a produced hyaline process,
sheathed and jointed ; on freshwater
Algae.

M. (sruc,inosa (PI, 52. fig. 10).

BiBL. Rabenhorst, Alg. ii. 225 ; Kiitz.
Phyc. Oentr. 232.

MASTOGLO'IA, Thwaites.— A genus of
Diatomacefe.

Distinguished by the Navicula-\\kQ frus-
tides, the hoops of which are furnished with
loculi, immersed in a^mammillate frond.

Five British species, marine and fresh-
water.

M. lanceolata (PI. 51. fig. 26). Valves
lanceolate, elliptical, ends acute ; loculi
8-30 ; in brackish water.

M. Danseii z= Uickicia Danseii, Thw.

BrsL. Smith, ^/-i^. Diat. ii. 63; Thwaites,
Ann. N. H. 1848, i. 171.

MASTOGO'NIA,Ehr.— A doubtful genus
of fossil Biatomaceae.

Char. Frustules single ; valves dissimilar,
angular, mammiform, orbicidar at the base,
free from umbilical processes, not cellular,
angles radiating.

The (eight) species are interesting from
the structure of the two valves of the frus-
tules differing. Thus in one, M. Crux (PI,
18. fig. 23 a) the angles and rays are four
in one valve, but seven in the other ; in

Fig. 452.

Fig. 453.

Fig. 454.

Matonia peetinata.

Fig. 452. Part of a fertile pinna. Magn. 3 diams.

Fig. 453. Indusium opened at the side, showing theca»
in situ. Magn. 2.5 diams.

Fig. 454. The same with the theose removed. Magn.
25 diams.

MATONIA.

C 493 ]

MEASUREMENT.

M. actt7iopti/chus (PI. 18. fig. 23 b) the

angles and rays are nine in one valve, and
thirteen in the other, and so on. Diameter
from 1-1600 to 1-300".

M. he.va<iona (PI. 18. %. 25).
BiBL. Ehrenb. Bet: Bed. Akad. 1844;
Kiitz. Sp. Alg. 25.

MATO'NLl, R. Brown.— A genus of
Cvathese (Polypodiaceous Ferns).

M. pectinata (figs. 452-454) Exotic.
(Hook, Si/n. 45.)

_ MAUliAN'D YA.— A genus of Scrophula-
riacese (Dicotyledons), the testa of the seed
of which is composed of cells with spiral-
fibrous deposits, foradng an elegant micro-
scopic object.

MEASUREMENT and Measures.— In
this article we shall consider the method
of measuring the magnifjang power of a
microscope, of ascertaining the dimensions
of objects, and shall give a sketch of the
standard measures in which the dimensions
of objects are expressed.

Measurement of the magnifying power of
a microscope. — The apparent size which an
object appears to possess under a micro-
scope will vary according to the power of
the object-glass and of the eye-piece used,
and the length of the body of the micro-
scope ; and it is a good plan to determine
the measurements once for all in the case
of the various object-glasses and eye-pieces,
keeping them wi-itten upon a card, so that
they may be readily accessible.

The apparatus requisite consists of a
glass micrometer-slide graduated into thou-
sandths of an inch, each tenth division being
marked by a longer line ; or two separate
slides, one graduated into thousandths, the
other into hundredths of an inch ; and an
ivory scale, graduated into inches, tenths,
and hundredths.

The simplest method is that by double
sight, as it is called. The micrometer-slide
is placed upon the stage, the lines brought
into focus, and the image of one of the
interspaces, as seen upon the stage with the
open eye not used in looking through the
microscope, is measured with compasses.
By then dividing the measure of the image
of the space by the known measure of the
unmagnitied space, the quotient is the
required magnifying power. Thus, if the
space on the micrometer-scale is equal to
the 1-lOOth of an inch, and the image of
the magnified space corresponds to S-lOths
of an inch, the space is magnified 50 times :

The same result may be obtained with
the aid of the camera lucida, by placing the
microscope horizontally, and its axis at a
distance from the table equal to the distance
between the focus of the eyepiece and the
stage ; the breadth of the image of a division
is then measured as before ; and this is the
best and most certain method.

A most important point in relation to
this subject is that the joint of the micro-
scope shall be furnished with a stop or pin
(Introduction, p. xv), by which the body
may be placed horizontally at once, so that
all objects which are drawn under the
same object-glass and eyepiece may be
magnified to the same extent, the degree
being determined by the second of the
above methods.

The obvious use of being acquainted
with the magnifying power of a microscope
is that objects under examination may be
viewed by the same power as that with
which figures of them have been made, so
that the structure or appearance of the
objects in the two cases may be compared.
In the above estimation of the magnifying
power, one dimension only is taken into
accoimt, viz. the breadth or diameter; and
this is the ordinary manner in which the
magnifying power is stated ; objects are
then said to be magnified so many dia-
meters, or so many times linear.

Measurement of the size of objects. — This
is efi'ected with the aid of a slide micrometer
passed through two slits in the eyepiece
above the stop, and at the focus of the upper
glass of the eyepiece. The breadth of the
spaces between the lines must be such as to
give an even and minute fraction of an inch.
The value of the spaces will vary with the
power of the object-glass and eyepiece ; so
that it must be determined in each case,
and recorded. For measuring small objects,
the breadth of the spaces in the eyepiece-
micrometer may be such that twenty of
them correspond to 1-lOOOth of an inch
in the stage-micrometer slide, so that the
value of each division wiU be the l-20,000th
part of an inch. It is seldom that we have
to measure objects so small as this ; but the
small size is of great advantage, because in
most cases it will happen that the margins
of the objects will coincide exactly with
some of the lines, whereby the chance of
error in computation will be avoided. For
larger objects, the spaces of the eyepiece-
micrometer may be coarser.

The method of measuring scarcely requires

^lEASUREMEXT.

[ 494 ]

MEASUREMENT.

further explanation. Supposing, however,
that the divisions of the stage-micrometer
are equal to 1-lOOOth of an inch, and
those of the eyepiece-micrometer equal to
l-20,000th of an inch (i. e. twenty of them
cover one space in the former), an object
brought into focus and covering five of the
spaces of the eyepiece-micrometer, will be
l-4000th of an' inch in diameter ; and so
for other dimensions. "When the objects
are large, the compasses and the ivory scale
wiU suffice for their measurement ; but
sometimes this may be conveniently done
under a low power, for the 1-lOOths of an
inch are not very clearly discernible to all
eyes.

In measuring objects, they must be co-
vered with thin glass, and not immersed in
too much liquid.

It is a matter of great diSiculty, under
high powers, to adjust accurately the divi-
sions of the eyepiece-micrometer to those
of the stage-micrometer, or to the margins
of objects, by means of the movable stage ;
a very ingenious apparatus has been con-
trived by Jackson to overcome the diffi-
culty. It consists of a little brass frame,
in which the eyepiece-micrometer slides
from side to side, the motion being com-
municated by the end of a screw working
against one e"nd of the slide, and resisted at
the other by a spring ; and as the magiii-
i'ying power with which the divisions of
the eyepiece-micrometer are viewed is
small, the adjustment is easily and accu-
ratelv effected.

Hartnack's diagonal scale is very useful ;
and very minute investigations and mea-
surements may be taken with it and
with Jackson's eyepiece-micrometer to
l-100,000th of an inch.

Other micrometers, as the "cobweb-
micrometer," are made ; but as they are
very expensive, we shall pass them over.

Some authors express the measurement of
objects by means of a ruled scale appended
to the figures or plates of them, the scale
consisting of divisions of a stage-micrometer
of known value traced off" under the same
power as the objects themselves; or some-
times the divisions are ruled over the figures.
These methods are very objectionable, be-
cause the size of the objects cannot be
ascertained without measuring with com-
passes and calculation, which is almost as
bad as the size being omitted altogether.

Whenever figures of objects are given,
the magnifying power with which they are

drawn should always be expressed in num-
bers near the figures.

Measures. — The measures in which the
dimensions of objects are expressed should
consist of parts of an English inch, and not
of a line. On the continent, fractions of a
millimetre, or of a Paris, or Prussian line are
used. When fractions of a millimetre are
adopted, this is usually denoted by the
addition of """ to the figure or figures.

The following data wiU be found useful
in reducing the foreign to tlie English mea-
sures : — -

A millimetre = 0'0393707 English inch ;
or rather less than l-2oth of an English
inch.

A centimetre = 0"393707 Eng. inch ; or
rather more than l-3i'd Eng. inch.

A Paris line = 0-088815 Eng. inch ; or
rather more than 1-11 th Eng. inch, to which
vulgar fraction it is nearest.

To convert a foreign into the English
measure, the former must be multiplied by
its unit-value; thus, Q-2b^^ (millimetre) X
0-0303707=0-G0984267o Engl. inch. But
in most cases a few decimal places only
need be observed. In this way, however,
w-e get a rather long sum, which may be
avoided by the use of the following Table.

Table for conversion of foreign into English
measures.

Millimetres

Old Paris lines

Prussian lines

into

into

into

English inches.

English inches.

English inches.

1

•039370

•G88815

•085817

2

•078741

•177630

•171633

3

■118112

•266445

•25745

4

•157483

•355260

•343267

6

•190853

•444075

•429083

6

•236224

•532890

•51490

7

•275595

•621705

•600717

8

•314966

•710520

•686532

9

•354337

•790335

•77235

in which the numbers in the first (or left-
hand) column correspond to the denomi-
nations expressed in the uppermost (head)
line of the three broader columns, while
the fractions opposite these numbers denote
their values in parts of the denrmiinations
of the lowermost (head) line. Thus, 1mm =
0-039.370 Eng. inch; 3""ii' = 0118112 ; 2
Prussian lines = 0171033 Eng. inch, and
so on. In using this Table, the decimal

MEDULLA.

[ 495 ] MEDULLARY RAYS.

fraction to be converted into parts of an
Eno-litih inch luiL-t be broken up into its
decimal parts, and each valued separately
from the Table; thus, to convert 0-75""" into
a fraction of an Eu'^lish inch —

(by tbe Table).

0.7mm _ 0-0275-j9o

O-Oo""" = 0-00 1968.53

0.75mm _ 0-02952803 Eng. inch.

The only circumstance which requires
attention iii the use of this Table is the
position of the decimal point. Thus, in the
above measure of O-ro'""^ which, when
broken up, makes O"?'"'" and O-Oo"""*, if the
first value (0-7) had been 7-0, the value in
Eng. inch would have been, according to
the Table, 0 275595 Eng. inch ; but this is
10 times too much, or = 7 whole milli-
metres ; hence the shifting of the decimal
point, and so on. To express the mode of
proceeding by rule, — the decimal point in
the fraction of an English inch given by
the Table should be shifted to the left, and
as manj- ciphers added as there are decimal
places in the foreign measure.

Harting introduced a new measure, the
.j^t__th of a millimetre = •0000a9 in., called
a micromillimetre, expressed by /x. This
and its multiples are often used in foreign
works. The /x is nearly equal to the tsW
of an English inch. But we agTee with
Frey, that its use possesses no advantage.

Throughout this work the foot and inch
and their fractional parts are expressed for
brevity by placing respectively one or two
acute accents on their right side : thus, one
foot is denoted bv 1', one inch by 1", and
' ' ^ ' 10".

.j^^th of an inch bv 1

MEDUL'LA OF Plants. — The

name

formerly applied to tlie pith of Dicotyledons
(fig. 455 Mj, from a supposed analogy with

Fio'. 455.

the medulla epinalis of animals. It affords
excellent sections of regular parenchyma-
tous tissues, as in the elder and in the tall
annual stems of many of the larger peren-
nial herbaceous plants. It sometimes be-
comes curiously chambered as it grows
older, as in the walnut and the jasmine ;
very frequently, however, it decays after a
time, leaving the centi-e of the stem hollow;
this same hollow condition occurs early in
tistular stems, such as tbose of the Um-
belUferse, from the pith being torn up by
rapid expansion of the wood. The Mono-
cotyledons do not generally possess a defi-
nite pitli ; the cellular mass, in which the
isolated Fibeo-vascular Bundles are
imbedded, answers to a diffused pith, or
rather to the pith and medullary rays col-
lectively. It may be seen well in sections
of the flowering stem of lilies (fig. 456 M).

Fig. 456.

Horizontal section of a yearling shoot of a Dicotyle-
don. M.iQedulla; RM, medullary rays ; T, medullary
sheath. Magnified 25 diameters.

Horizontal section of the Howering stem of a lily.
M, medulla ; F, fibro- vascular bundles.

Magnified 5 diameters.

A more definite medulla occurs in the stem
and leaves of the rushes and sedges, where
also the cells are often elegant radiating
forms, leaving large air-canals between
them (PI. 47. fig. 18). The pith of a Dico-
tyledonous stem loses itself gi-adually in
the terminal bud, where it is confounded
with the nascent wood and cortical layers.
In this stage its cells possess an active
\-italitv, which, however, is soon lost.

ME'DUL'LARY RAYS.— The processes
of cellular tissue extending outwards from
the pith, between the fibro-vascular bundles
of a Dicotyledonous stem in the fir.^t year
of gi-owth (fig. 455 RM), together with
additional interpose'd rays formed between
the older in each succeeding annual layer
of wood (fig. 457, 1, 2, 3, 4). The tissue of
these rays generally becomes much com-
pressed durino: gi'owth ; but their size and
the degree of development differ much in

IMEDULLARY SHEATH. [ 496 ]

MELANCONIEI.

different cases. In radial sections of Dico-
tyledonous wood they often appear distinctly
to the naked eye, from the direction of their
cells being different from that of the woody
fibre, and therefore reflecting light dif-

Fig. 457.

Section of a four years' old shoot of the Cork oak. M, pith ;
1, 2, 3, 4, medullary rays of successive years ; P. C, liber layers ;
S, cork layers.

Magnifled 20 diameters.

ferently ; this causes the "silver grain" as
it is called of oak panels, &c. ; in tangential
sections of the trunk, the ends of the me-
dvdlary rays usually appear as short, more
or less regidar, narrow streaks.

MED'ULLAR Y SHEATH.— The earliest
layer of fibro-vascular tissue developed in a
Dicotyledonous stem, consists ordinarily of
spiral vessels, these forming the foundation
of the wood-bundles (fig. 4oo T). As the
latter stand in a circle round the pith, their
internal vascular layers of course form col-
lectively a continuous cylindrical envelope
to the pith ; this is called the medullaiy
sheath. It is absent in some Dicotyle-
donous stems, for example in the Oroban-
chacese.

MEDU'S^E. See Acaleph^.

MEE'SIA, Hedw.— A genus of Bartra-
mioid Mosses ; one species, M. uliginosa
( = Bnjiim trichodes) , certainly British ;
another. 31. lonr/iseta, doubtful.

MEESIA'OKE.— AtribeofBartramioid
Mosses, containing two genera, of which
there are but few British representatives.
See Meesia and Paludella.

MEGALOT'ROCHA, Ehr.— A genus of
Rotatoria, of the family Megalotrocha^a.

Char. Eyes two, red, sometimes disap-
pearing with age.

Rotatory organ two-lobed or horse-shoe-
shaped ; teeth in rows.

M. albo-flavicans, E. (PI. 44. fig. 1).
Colourless and unattached when young,

yellowish and grouped in radiant clusters
when old; freshwater; length of individuals
1-36"; of the clusters 1-6".

The ova remain some time attached to
the parent by a cord.

M. velata, Gosse.

BiBL. Ehr. Lifus. 396; Gosse,
Ann. N. H. 1851, viii. 198 ; Pritch.
Infus.

MEGALOTROCH/E'A, Ehr.— a
family of Rotatoria.

Char. Neither envelope nor cara-
pace present ; rotatory organ simple,
notched or sinuous at the margin.
Three genera :

Eyes none Cyphonautes.

Eyes present

Eye one Microcodon.

Eyes two JJegalotrocha.

BiBL. Ehr. Infus. p. 394.
MEGAM'ERUS, Duges.— a genus
of Trombidiua (Acariua).

Char. Palpi long, fi-ee, with a claw ;
mandibles forcipate; body constricted;
coxse^ distant ; legs ambulatoiy — femora,
especially _ of the fourth pair, "very large,
seventh joint short.

Several species. They live in damp
shady places, and move rapidly.

M. celer (PL 6. tig. 33 : a, labium ; b,
palp). Minute; abdomen oblong; the sides
narrowed posteriorly, covered with hairs,
and with three terminal set«; labium bifid ;
mandibles with a movable, elongated, pointed
and curved claw.. *

PI. 6. fig. 33 c, mandible of M. roseus.
BiBL. Duges, Anyi. Sc. Nat. 2 ser. ii. 50 ;
Walck. Arachn. iii. 169 ; M
Ent. 115.

Gervais,

Lurray,

MEGAP'ORA, Hincks, = Lepralia pt.
(Hincks, Pohjz. 171.)

MEGU'RA, Buckt.— a genus of Aphidse.
Black, eyes red ; on Vicia septum. (Buck-
ton, Aphid., Bay Sue. i. 188.)

MELAMPSO'RA, Cast— a genus of
Uredinei (Coniomycetous Fungi), distin-
guished by producing two distinct kinds of
spores — summer and winter spores. The
species are very common on the willow,
birch, poplar, &c., forming yellow or orange
spots upon the leaves. (Cooke, Handh.
522 ; Tulasne, Ann. Sc. N. 4. ii. 94.)

MELANCONI EL— A provisional family
of Stylosporous Fungi, distinguislied from
SphiTcronemei by the perithecium being ob-
solete or altogether wanting. The spores,
which vary much in the different genera,
are ultimately protruded in the form of

MELANCONIUM.

[ 497 ]

MELOPHILA.

tendrils or otlier-svise. They are all mere
forms of Sphaoriacei.

MELA^CO'NIUM, Lk. — A supposed
genus of Melauconiei^(Stylosporous I uugi ),
so called from forming a kind of black rust
on branches of trees, reeds, &c. Several
species have been found in Britain. The
commonest is M. bicolor (Didi/i}wsj)orium
ekvatum, Br. Fl.), on twigs of birch. Fries
places also Cnjptosporium vulgare here.
These plants are forms of Sphaeriacei. See

COXIOMYCETES.

BiBL. Berk. Brit. Flor. ii. pt. 2. p. 357 ;
Ann. N. H. vi. p. 438 ; Fries, Summa Veg.
p. 508 ; Tulasue, Ann. d. Sc. Nat. 4. ser. v.
p. 109.

MEL'ANINE.— The black or brown pig-
ment met with in the choroid and uvea ; in
the rete mucosum of man, especially the
negro, and animals ; in hair, feathers, &c.;
a)id in the blood in malaria. These pig-
ments are derived from htematine and
hsemoglobine, and exist usually in the
form of very mmute granules. They are
insoluble in watey, alcohol, ether, and
acids: but are sometimes soluble in alkalies
or solution of chlorine. The lungs and
bronchial glands often contain a black pig-
ment, which is unacted upon by these re-
agents, and is derived from carbonaceous
matter admitted through the respiratory
organs. (Rindfleisch, Path. Hist, 167 ;
Hoppe-Sevler, Ati. Chim. 240.)

MELANOGAS'TER, Cd.— A genus of
Hypogaeous Gasteromycetous Fungi. Two
species occur in this coimtry, under beech,
Lombardy poplars, &c. M. variegatus (fig.
54, p. 92) is sold in the market at Bath
under the name of Red Truffle, but it has
none of the fine flavour of the real Truffle.
M. ambiguus is very fetid, smelling like
assafcBtida.

BiBL. Tul. Fung. Hyp. t. 2. f . 4, 5 ; Berk.
Outl. 293 ; Cooke, Handh. 356.

MELANOTHE'CA, Fee.— A genus of
Pyrenodei (Lichenaceous Lichens).

Char. Thallus scarcely any; apothecia
verrucaroid, numerous, confluent ; hjTnenia
scarcely distinct ; perithecium black ; spores
8, variously divided. Two British species^
on trees. (Leighton, Lich. Flora, 498.)

MELAS'MIA, L^v. — A supposed genus
of Sphaeronemei (Coniomycetous Fungi),
but apparently only a stylosporous form of
Rhytisjl\. M. acerina occurs on the
leaves of the sycamore, forming black spots,
sometimes as much as 1-2" in diameter.

BiBL. Berk. Ann, N, H. 2 ser. v. 456 ;

E^veiU^, Ann. Sc. Nat. 3 s^r. v. 276 ; Fries,
Summa Veg. 423.

MELASPTLEA, Nyl.— A genus of Gra-
phidei (Lichenaceous Lichens).

Char. Apothecia black, superficial, artho-
noid ; spores 1-septate ; paraphyses distinct.
Five species. (Leighton, Lich. Flora, 436.)

MELICER'TA, Schrank.— A genus of
Rotatoria, of the family Floscularitea.

Char. i3odies each iu an isolated tubular
carapace or urceolus ; rotatory organ fom-
lobed ; eyes two, at least when young.

M. ringens (PI. 44. fig. 3 ; fig. 4, animal
removed from the sheath ; fig. 6, jaws).
Carapace conical or cylindrical, brownish,
composed of numerous rounded or discoidal
bodies agglutinated together ; body colour-
less. Length of carapace 1-36 to 1-24".

Frequently found attached to water-
plants, especially Fotamogeton crispus.

BiBL. Ehr. Infus. 404; Williamson,
3Iicr. Jn. 1852 ; Gosse, Tr, Mic. Sac. 1851,
iii. 62 ; Bedwell, Jn. Mic. Soc. 1878, 176 ;
Ann. N. H. 1881, viii. 448.

MELI'OLA, Fr. — A genus of Ascouiyce-
tous Fungi, belonging to the division Peii-
sporiacei.

All the species are exotic, occurring on
various leaves, and distinguished by their
highly developed mycelium and large septate
sporidia,

BiBL. Leveille, Ann. Sc. Nat, 1846, v.
266 ; Mont. Cuba Crypt. 327.

MELOBE'SIA, Lam.— A genus of Coral-
linaceae. Nine British species, on rocks and
other Algae (Harvey, Mar. Algce, 107). The
capsules (ceramidia) form little blimt cones,
scattered over the crusts, and containing
tufted tetraspores as in Corallina.

MELOLON'THA, Fabr. (Cock-chafer).
— A genus of Coleopterous Insects, family
Melolonthidae.

The structure of M, vidgaris, the common
cock-chafer, has been elaborately studied
and described.

BiBL. Suckow, Naturg. d. Maikdfers ;
Straus-Diirckheim, An. comp. d. Insect, j
Westwood, Introd.

MELOPHTLA, Nitzsch {Melophagm,
Latr.). — A genus of Dipterous Insects,
family Hipj:)oboscidce.

Char. Head posteriorly received iu an
excavation of the thorax ; wiugs and halteres
absent; last joint of the tarsus largest.

M. ovinus, the sheep-tick (PI. 35. fig. 23).
Common upon sheep. Antennae small, sunk
in an eye-Uke cavity of the head ; eyes small,
oval, resembling two groups of ocelli ; setae

2k

MELOSIRA.

[ 498 ]

MEMBRANES.

three, enclosed in two sheath-like, hairy,
iinjoiuted organs (labial palpi), resembling
otherwise those of Pulex, and arising from
the sides of a triangular labium. Legs
robust ; tarsi with two stout serrated claws,
each having at its base a blunt process ;
accompanying the claw is an elegant feathery
tarsal brush ; and on the under side of the
last tarsal joint is a bilobed pectinate organ.

BiBL. Lyonnet, Anat. et les mctamor.
Gurlt, Magaz.f. d. rfesam. Tliier. 1843, ix.
Westwood, Introd. ; Curtis, Br. Entom. 142
Dufour, An7i. Sc. Nat. 1845, iii. ; Leuckart,
Fvrtpfanz. der Pupiparen.

MELOSI'RA, Ag. {GalUonella,mir.).—
A genus of Diatomaceag.

Char. Frustules cylindrical, discoidal or
subspherical, united into jointed filaments.

Hoops often very broad, to adapt them-
selves to the breadth of the new frustules.
In some species a narrow projecting ridge
or keel encircles the valves near their ends.
Valves covered with dots, which are mostly
very minute and invisible under ordinary
illumination ; in the side view they some-
times have a radiate arrangement. In some
species the margins of the ends of the frus-
tvdes (side view) have coarse and distinct
radiating striae.

This genus has been subdivided by
Ehrenberg and Kiitzing into : — Lymjonmrn,
in which the keel is present ; and Gallionella
(proper), in which this is absent. Again, by
Thwaites into : — Aidacosira, in which the
frustules are cylindrical, surrounded trans-
versely by two furrows, with rounded (con-
vex) ends, but no line for division ; Orthosira,
in which the frustules are exactly cylindrical
(with flat ends), exhibiting the transverse
line of division, and with spherical or sub-
spherical internal cavities ; and Melosira
(proper), in which the frustules are convex
at the ends, and have the central line of
division.

Numerous British species.

* Marine.

M. nummnhides, Kg. (PI. 17. fig. 5 a ;
h, a frustule more magnified). Prepared
frustules colourless, distinct keel pn sent ;
valves without markings imder ordinary
illumination; breadth 1-1500 to 1-1200".

This common species forms long, slightly
curved chains, and, on account of the great
breadth of the frustules, shows well the
various stages of subdivision. The filaments
are sometimes stipitate.

M. Borreri, Grev. Prepared frustules
dark brown, ends rounded, entire surface

punctate (ordin. ilium.), no striae nor keel ;
breadth 1-850 to 1-5C0".

M. Uiclxiei (^Orthosira Dickiei, Thw.)
(PI. 17. fig. 15: a, front view; b, side view).
Filaments short, frustules nearly colourless,
ends flat, no striae nor keel (ord. ilium.),
valves thickened so as to render the cavity
of the frustules rounded ; breadth 1-1500 to
1-1200".

The remarkable sporangia formed in this
species (PI. 10. fig. 0) are noticed under

DlATOMACE^, p. 249.

** Freshwater.

M. {Orthosira) varians (PI. 17. fig. 6,
front view ; a, side view). Frustules colour-
less, ends sHghtly convex and striated at the
margin (ord. ilium.), keel absent; breadth
1-1500 to 1-1200". The end view of the
frustules resembles that of Cychtella.

Formation of sporangia shown in PL 10.
fig. 8 o ; 6, sporangial frustule.

31. arenaria. Ends of frustules flat and
striated at the margin (ord. ilium.), the striae
appearing also in the front view; keel
absent ; frustules broader than long; breadth
1-660 to 1-260".

M. cremdata, Kg. (Aulacosira crenulata^
Thw. ; M. orichalcea, Ralfs) (PI. 10. fig. 7 a,
forming sporangia; h, c, sporangial frus-
tules). Differs from the last in its less
diameter, and the frustules being two or
three times as long as broad; breadth
1-1400".

BiBL. Kiitz. Bacill. 52, Sp. AJg. 27;
Ralfs, An7i. ISf. 11. 1843, xii. 346; Thwaites,
ibid. 1848, i. 168 ; Smith, Br. Biat. ii. 54 ;
Rabenh. Aly. ii. 37 ; O'Meara, Q. Mic. Jn.
ix. 150.

MELOXAN'THUS, Buckt.— A genus of
Aphidae. M. salicis. Black, legs orange,
antennae 7-jointed; on the willow. (Buckton,
Aiihid., Bay Soc. ii. 21.)

MEMBRANES, Undulating. — These
are said to be simple membranous bands,
one margin only of which is attached, the
other being free and exhibiting an undu-
latory motion. They are allied to and
answer the same purpose as cilia. They
are described as occurring upon the sper-
matozoa of salamanders and tritons ; as
forming longitudinal processes in the water-
vessels of some Anellida, as the Turbellaria;
also as existing in some Infusoria, as Tricho-
dina, and some Rotatoria. Some authors
have regarded them as consisting of rows of
cilia or a spiral fibre, and not membranes.
They are most easily examined in the sper-
matozoa of the triton, in which we believe

MEMBRANIPORA.

[ 499 ]

MERfDION.

the appearance of an undulating membrane
arises* from the existence of a tibre coiled
around tlie spermatozoa, and uudulating
throughout its length (PI. 60. fig. 17).
This opinion is b.ased upon the circumstance
that if the coiled fibre be detached from the
proper tilament of a spermatozoon or sper-
matozoid, no margins of the (lacerated)
membrane can be detected other than that
visible at first, and which really represents
the coiled fibre". This, however, is an in-
teresting subject for further investigation.
Siebold, who has paid most attention to it,
remarks that Trypanosoma Grubii, a sup-
posed entozoon found in the blood of frogs
and fishes, is not an independent animal,
but simply an undulating membrane swim-
ming freely.

BiBL. Siebold, Sieb. und Soil. Zeitschr.
Bd. ii. 356, and the Bihl. therein.

See Mucous and Serous Membranes.

MEMBRANIP'ORA, Johnst.— A genus
of marinePolyzoa, family Membraniporid.^.

Several British species; usually fcniud in-
crusting sea-weeds, more rarely shells and
stones.

M.inlosa (PL 41. fig. 18). Orifices of the
cells with one long hair, and several spinous
teeth. Verv common.

MEMBR AIsIPOREL'LA, Blainv., =ie-
praKa, pt. (Hiucks, Polyz.).

MEMBRAXIPOR'ID.E.— A family of
Cheilostomatous Infundibulate Polyzoa.

Distinguished by the expanded, incrust-
ing, stony polypidom, and the horizontal
quiucuncial cells. Genera :

Memhranipora, Cells open in front, with
raised margins.

Lepralia. Cells closed in front, poly-
pidom spreading circularly.

BiBL. Johnston, Br. Zooph. ; Busk, Cat.
Mar. Folyz. ; Gosse, Mar. Zool. ii. 16 ;
Hincks, Poli/z. 127.

MEXI'PEA, Eamx.— A genus of Infun-
dibulate Cheilostomatous Polyzoa, family
Cellulariadpe.

Char. Cells oblong, tapering downwards,
not perforate behind, with one or two sessile
birds'-heads in front below the orifice. Two
British species.

M. ternata {Celhdaria ternata, Johnst.).
Cells elongated, gi'eatly tapeiing down-
wards, .3 in each internode, with a stalked
operculum protecting the orifice ; operculum
expanded, entii-e, two spines on the upper
margin ; anterior birds'-head single.

BiBL. Johnston, Br. Zooiyh. '6\jo; Busk,
Cut. 20 ; Hiucks, Puhjz. 36.

_ MENIS'CIUM.— A genus of Grammi-
tidete (Polypodiaceous Ferns).

10 sp. ; tropical. (Hook., ^yn. 390.)

MENISCOS'TOMUM, Kt.— A genus of
Holotrichous Infusoria. Like Paraniociutny
but mouth lateral, lunate ; Avith a ^abratile
membrane. 1 sp. ; fr. wat. (Kent, Inf. 539.)

MENIS'PORA, Pers.— A genus'of Mu-
cedines (Hyphomycetous Fungi), one species
of which, M. lucida, Corda, is recorded as
British, growing on decayed wood.

BrBL. Berk, and Broome, Ann. N. H.
2 ser. vii. 101 ; Corda, Ic. i. pi. 4. fig. 223.

MENOID'IUM, Perty.— A genus of
Flagellate Infusoria.

Char. Small, crescentic, thicker on the
outer margin, colourless, or greenish.

M. pellucidum, fi'eshwater ; movement
jerking and revolving, 1-670 to 1-430".

BiBL. Perty, Lehensf. 174.

MENOPON, Nitzsch.— A subgenus of
LiOTHEUM (Anoplura); with the head
semilunar or trapezoidal, but witliout a deep
lateral sinuosity. The species infest poultry,
the partridge, quail, &c.

MEREN'CHYMA.— A name applied by
some authors to the form of vegetable cel-
lular tissue where the cells are of circular,
ellipsoidal, or irregularly rounded outline;
ordinarily known as lax parenchyma.

MERIDTON, Leibl.— A genus of Diato-
macese.

Char. Frustules (in front view) wedge-
shaped, united laterally so as to form seg-
ments of circles or spiral bands. Fr. wat.

Frustules in side view obovate, and fur-
nished with coarse transverse strias visible
under ordinary illumination, which extend
into the front view.

Kiitzing distinguishes Meridian, in wliich
the frustules form a spiral (helical) band,
from Eumeridion, in which they form a con-
volute band.

Meridian circulare, Ag. (PI. 17. fig. 7 :

a, front view ; b, side view). Frustules in
side view simply obovate, forming a spiral
(helical) band or , filament ; length of frus-
tules 1-600 to 1-375".

Meridian conMrictum, Kg. (PI. 16. fig. 28,
filament fiattened, and frustules (front view)
separated by drying ; a, convolute filament ;

b, side view). Frustliles in side view con-
stricted near the broad end, attenuate to-
wards the narrow end, and attached to a
hemispherical stipes or cushion.

BiBL. Kiitz. Bacill. 41, Sp. Aly. 10:
Ralfs, Ann. N. I£. 1843, xii. 457 ; Smith,
Br. Uiat. ii. 5 ; Rabenh, A/y. i. 295.

2k2 .

MEKISMOP^DIA.

[ 500 ]

MESODIXnBI.

:MERISM0P^E'DIA, Meyen.-A genus
of Confervoid Algfe, consisting of minute
cells, arranged in fours and multiples, form-
ing a quadrate layer or plate. Several
species are described ; but their relation to
Goniitm is obscure. Sarcina is placed in
this genus by Rabenhorst ; hut Sarcina
forms a cube. See Saecixa and Gonium.
(Rabenhorst, Fl. Alg. ii. 56.)

MERIZOMY'RIA, Ktz.— A genus of
Rivulariacefe.

Char. Filaments moniliform, upper cells
subulate, basal cells contained in a mucous
matrix, and constituting an amorphous
thallus. Freshwater.

EiBL. Rabenh. Fl. Alg. iii. 224.

MERMIS, Duj. — A genus of Entozoa.

M. niyrescens resembles Gordius, but dif-
fers from it principally in the Aulva of the
female being transverse and situated near
the anterior end of the body, whilst in Go?--
dius this is placed at the posterior end.
Eggs black.

It is found in the newly dug-up damp
eai-th of gardens, and in the intestines of
insects.

BrBL. I~)uj. Ann. Sc. Nat. 2 ser. xviii.
129, and Helminthes, 294; Siebold, Ent. Zcit.
1842, 146; Meissner, Sieb. and Koll. Zeit-
schrift, 1853.

M'EROT'RICHA, Mer.— A genus of Fla-
gellate Infusoria. Free, oblong, green ; fla-
gelliun single, ventral; with anterior tri-
chocysts. 1 sp., freshwater. (Kent,//?/. 249.)
MERU'LIUS, Hall. Dry-rot.— A genus of
Hymenomycetes (Basidiomycetous Fungi),
distinguished by the veiny or sinuously
plicate folds of the hymenium, these folds
not being distinct from the flesh of the
pileus, and forming angular or serrated pores.
M. lachrymans is the dry-rot fungus. The
mycelium is composed of filaments creeping
in the substance of the infected wood, dis-
organizing and feeding on this as it decays.
The mass is at first white and cottony, form-
ing an effused pileus from 1 to 8" broad ;
subsequently ferruginous or deep orange.
The in-egular folds finally discharge a
watery liquid, whence the name.

The most efficacious remedies against diy-
rot are creasote and carbolic acid. Cor-
rosive sublimate, though at first efficacious,
seems to lose its virtue after a time.

Several species of the genus have been
found in England in addition to J/, lachry-
ynans.

EiBL. Berk. Br. Fl. ii. pt. 2, 129 ; Sow-
erby, Fungi, pi. 113,

:MES0CAR'PUS, Hassall {Sjyhcerocarjms,
Kutz.). — A genus of Zygnemaceae (Confer-
void Algae), with evenly distributed cell-
contents, producing in conjugation a cross
branch, in which is formed a round spore.
It often happens that all the successive
members of a long series of cells conjugate
with another similar series, so as to produce
a ladder-like body, the "roimds" of which
are formed of the transverse processes (tra-
hecidce, KUtz.). The only kind of repro-
duction yet observed is that by the spores
formed in the transverse branch from the
conjoined contents of two cells; but it is
possible that zoospores and encysted con-
ditions of these occur, as in Spirogyba and
MouGEOTiA. The stellate encysted bodies
found in most of the allied plants have been
seen in M. scalaris by Thwaites. Thwaites
also observed a division of the contents of
the spore into four parts, such as occurs in

ffiDOGONrE^.

M. scalaris, Hass. (fig. 138, p. 204).
Sterile filaments 1-1800 xo 1-1440" in dia-
meter, 6 times as long ; sporanges oval or
round. Hass. pi. 42.

M. depressus, Hass. Sterile filaments
1-2880 to 1-2400" in diam., 6 to 8 times
as long ; spores globose or elliptical. Hass.
pi. 44. fig. 1.

M. intricatus, Hassall, is apparently the
same as M. scalaris; all the other forms
mav be brought under M. depressus.

BiBL. Hassa.U, Alg. 166, pis. 41-45;
Kiitzing, Sp. Alg. 435 ; Tab. Phyc. v.
{Splicer ocar pus), pis. 5-7 ; Thwaites, Ann.
N. H. xvii. 262.

MESOCE'XA, Ehr.--A doubtful genus
of Diatomacete, according to Ehrenberg
and Kiitzing.

The bodies refen'ed to this title consist of
single siliceous rings, oval or angular frame-
works, without a centre, and mostly with
external and sometimes internal spines ari-
sing from them ; man)^ are fossil.

Whether they are spicula of Echinoder-
mata or not, remains to be decided. Dia-
meter from 1-750 to 1-400".

M. octogona, Ehr., PI. 25. fig. 1.

BiBi.. Ehrenberg, Ber. Bert Ak. 1840 ;
Kiitzing, Bacill. 139, Sp. Alg. 142.

MESO'CHRA, Boeck.— A genus of Co-
pepodous Entomostraca, close to Cantho-
camptiis. 2 species ; brackish water. (Brady,
Cupep. ii. 62.)

MESODINTUM,_ Stein. — A genus of
Peritrichous Infusoria. Free, ovate, snout-
like in front, with a ring of setose cilia.

MESOGLOIA,

[ 501 ]

METOPIDIA.

2 species; fi-esliwater and marine. (Ivent,
Inf. (535.)

"MESOGLO'IA, Ag.— A genus of Clior-
dariaceas (Fucoid Algae), with filiform,
much-branched, gelatinous fronds ; the axis
of the filaments composed of interlacing
longitudinal cells, with gelatinous interposed
matter ; the periphery of radiating, dicho-
tomous, coloured filaments. The fructifi-
cation consists of unilocular and multilocular
sporanges; the former are ovate sacs (fig.
^8) occurring attached to the ramuli of

Fig. 458.

Mesogloia vermicularis.
Peripheral ramiili, unilocular sporanges and the fila-
ments upon which the jointed sporanges arise.

Magnified 50 diameters.

the periphery ; the latter are produced by
ramifications of other ramuli siu-rounding
them (fig. 458). Both kinds produce cili-
ated zoospores, which germinate. M. ver-
micularis (figs. 458, 459), an olive-gi-een

Mesogloia vermicularis.

Portion of a filament.
Magnified 10 diameters.

or yellowish frond, 6" high, is common on
rocKs and stones between tide-marks. M. vi-
rescens, a smaller species, is not uncommon.

BiBL. Harvey, Mar. Alg. 47, pi. 10 B ;
Phyc. Brit. pis. .31 & 83 ; Thuret, Ann. Sc.
Nat. 3 ser. xiv. 237, pi. 27.

MESOT^'RIUM, Nag.— Probably iden-
tical with Palmoglcca, (Archer, Qu. Mic,
Jn. iv. n. s. 109.)

METACYTRIS, B. & R— One of the
Ci/therid(e : carapace tumid and cordate ;
upper antennae long and setose. Lakes and
rivers of England, Ireland, and Holland.

BrBL. Bradv and Robertson, Ann. N. H.
4, vi. 19 ; ix. 51.

METACYS'TIS, Cohn.— A genus of
Holotrichous Infusoria.

Char. Free, ovate or elongate, ringed,
vesicular behind.

M. tnmcata, among decaying marine
algse. (Kent, Inf. 511.)

METAMORPHOSES of Tissues.— The
degenerations of the tissues, characterized
by an alteration in their quality and impair-
ment of function. They are divided into
metamorphoses and infiltrations. The meta-
morphoses are characterized by the direct
change of the albuminoid constituents of a
tissue into a new material, which is usually
followed by the destruction of the histo-
logical elements, and the softening of the
intercellular substance. They include fatty,
mucoid, and colloid degeneration.

BiBL. Green, Path, and Morh. Anat.

METEORITES.— In transparent sections
of small fragments of meteorites, many
mineral substances may be recognized here
and there ; but the microscope and even
polarized light fail to distinguish the kinds
of crystals. It is best to examine the
bruised debris ; and minute crystals may
be sorted out, and removed for microscopic
examination.

BiBL. Maskelyne, Proc. Roxj. Soc. 1870.

METOPI'DES, Quenn.— Like Metopus,
but with two or more posterior setfe. M,
contorta, freshwater. (Kent, Inf. -582.)

METOPIDIA, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eyes two, red, frontal ; foot forked j
carapace depressed or prismatic; anterior
and upper part of head naked or uncinate ;
no hood. = Lepadella with two frontal
eyes. Lorica closed beneath.

M. triptera (PI. 44. fig. 7). Carapace
ovate, accurately trilateral, crested on the
back. Freshwater ; length 1-288 to 1-144".

Four other species.

METOPUS.

[ 502 ]

MICROCOLEUS.

BiBL. Ehr. Infus. 477 ; Gosse, Ann. N.
H. 1851, Yiii. 201.

METO'PUS, Clap, et Lach.— A genus of
Heterotrichous Infusoria, fam. Bursarina.

Char. Buccal fossa oblique and elongate,
anterior part of the body prolonged ; ante-
rior cilia stronger than those of the rest of
the surface. M. sujmoides (PI. 52. tig. 11).

BiBL. Claparede et Lach. Inf. 254.

METRID'IA, Boeck.— A genus of Oo-
pepodous Entomostraca. M.armata, ma-
rine. (Brady, t'opejwda, i. 79.)

METZGE'RIA, Raddi.— A genus of Pel-
lieae (Hepaticse), comprehending Jumjer-
manmafurcata, L., and J!7J?<iesc«?.s,Schrank,
growing on trunks of trees, rocks, &c. in
very moist places. The fronds of both are
linear-dichotomous,membranous and ribbed.
M.fiircata is smooth above, hairy beneath ;
M. puhescens hairv on both sides and larger.

BiBL. Hook. Br. Fl. ii. pt. 1. 131 ; Br.
Jimgerm. pis. 65, 50, &: 73 ; Endlicher, Gen.
Plant. Supp. 1. 1338; Hofmeister, Vergl.
Untersitch. 10, pi. 4.

MICA. — This mineral substance, ■which
is often erroneously called talc in the shops,
was formerly used for covering mounted
objects, but is now replaced by thin glass.
It is, however, occasionally useful in apply-
ing a red heat to objects, as Diatomaceiie,
&c., where it is required not to change the
position of the object. It often contains
crystalline and crystalloidal inorganic mi-
neral substances, as metallic oxides, &c., of
interesting appearance.

Thin plates of mica are used also in bring-
ing out colours in objects with polarized
light. See Polar ization, and Rocks.

MICRASTE'RIAS, Ag.— A genus of
Desmidiacese (Coni'ervoid Algfe).

Char. Cell single, lenticular, deeply
divided into two-lobed segments ; lobes
inciso-dentate (rarely only bidentate), and
generally radiating.

Sporangia spherical, with stout spines
(PI. 14. tig. 12).

Numerous British species (Ralfs).

M. denticulata (PI. 14. fig. 11, undergoing
division ; fig. 12, sporangium). Cell cir-
cular, surface smooth ; segments five-lobed ;
lobes dichotoniously divided, ultimate sub-
divisions truncato-emarginate, with roundetl
angles. Length 1-113". Common.

M. rotata (PI. 14. fig. 13). Cell circular,
smooth ; segments five-lobed ; lobes dicho-
tomously incised, ultimate subdivisions
bidentate. Length 1-91". Common.

BiBL. Ralfs, Br. Dcsmtd. 08; Lobb, Tr.

Mic. Soc. 1861 ; Dixon, Mic. Jn. 1859 ;
Archer, Pritchard's Infus., & Mic. Journ.
1862 ; Bailey, Smith. Contr. ; Rabenh. Aty.
iii. 187.

MICROCLA'DIA, Grev.— A genus of
Ceramiacese (Florideous Algae), containing
one rare British species, M. r/landidosa (Pi.
4. fig. 7), with a dichotomously branched,
filiform, compressed frond 1 to' 2" high, of
a bright rose colour. Its fructification con-
sists of (1) roundish, sessile involucrated
favelliB with sjmres, and (2) tetraspores
(tetrahedrally arranged) imbedded in the
ramules.

BiBL. Harvey, Mar. Ah/. 160, pi. 22 B;
Phyc. Br. pi. 29 ; Grev. Alg. Br. t. xix.

MICROCOCCUS.— A genus of Schizo-
mycetes, distinguished by the minute or-
ganisms being globular instead of linear.
The species have been divided into 3 groups.
The chromogenous : as M. prodiffiosus,
which is blood-red, and frequently occurs
on Fungi, cooked provisions, red milk, &c.
(see Blood on Bread) ; M. hdeus, cyaneus,
violacetts {e\\\-^i\c^\) , aurani iacus, on cooked
potatoes and haitl white of egg; and M.
chlorimis on Bgo^, The zymcgenous, pro-
ducing various kinds of fermentation, as
31. crepuscidum = 3Ionas c, Ehr.; M. urea,
in Torida-fovm, 2-8, in urine, converting
the urea into carbonate of ammonia, and
decomposing hippuric acid. And the patho-
genous, by some considered globular Bac-
teria, producing contagious diseases : as 31.
vaccinas, in vaccine and variolous matter;
31. diphiheriticiis, oval, in twos or more,
sometimes in colonies ; 3t. septicus {3Iicro-
s^>o?-o??, Klebs), in the tissues and vessels in
pyaemia and septiciemia ; 31. homhycis, in
the intestines of silkworms ; and others,
very doubtful, in the blood and sputum of
measles, in scarlet fever, typhus, glanders,
and syphilis. CoUariiim, Lk., seems, at least
as regards some species, to be identical.

BiBL. Biill. Soc. hnp. dAi/ric. 2 S(5r. vii.
727; Comptes rcvdns, 1852, 119; Cohn,
Beit. i. 109, and ii. 148; Magnin, Bacteries;
Hallier, Phytopath.

MICROCO'DON, Ehr,— A genus of Ro-
tatoria, belonging to the family Megalotro-
cha5a.

Char. Eye single ; no carapace ; foot styli-
form. Jaws two, each with a single tooth.

3T. clavvx (PI. 44. fig. 8). Body compa-
nulate, foot equalling or exceeding the body
in length. Fr. wat. Length 1-288 to 1-216'"'.

BiBL. Ehr. Infas. p. 395.

MICROCO'LEUS, Besmaz, (Chthono-

MICROCYSTIS.

[ 503 ]

MICROTIIECA.

blasfu.-i, Kiitz?). — A gemi9t)f OscillatoriacefB
(Coiifervoid Alg« ), with frond.s I'oriuing-
strata on moist gTouiid, patlis, imul, &c.
These phints may be described as bundles
of Os(//A//o;vrt-fiLiments enclosed in a com-
mon ^n'lalinous sheath, which is simple oi'
irregularly dichotomously branched, and
forms twisted interwoven masses. The
structure of the filaments appears to bo
identical witli that occurring in Oscilla-
TORiA, described under that head ; the fila-
ments oscillate : the mode of origin of the
enclosing sheath is obscure ; but it would
appear to be formed of the gelatinous half-
dissolved outer membranes of the enclosed
filaments. No formation of spores or goni-
dia has been described. M. repens, Harv.
(PI. 8. tig. 9a, the open end of a sheath),
is very common on damp paths, kc, its
sheaths are branched ; M. aiiguiformis,
Harv., occurs on the mud of brackish
pools; its sheaths are said to be simple.
31. gracilis, Hrissall, said to be found in
similar situations, has no character attached
to it.

BiBL. Harvev, Mar. AUj. 227, pi. 26 D ;
Plu/c. Br. pl.24ij; Hassall, ^/(7. 260, pi. 70;
Kiitz. Tab. Fhyc. i. pis. 54-58.

JMICROCYSTIS, Kiitz.— A genus of
Palmellaceffi (Confervoid Algae), composed
of crowded minute spherical cells, enclosed
in a common envelope, forming- solid fami-
lies. M. protoc/enita (PL 3. fig. 12), bluish
green, in long-kept water.

BiBL. Kiitz. Sp. Alfj. 208; Tub. Phyc.
pis. 8, 9 ; Rabenh. Alg. ii. 51.

MICROGLE'NA, Ehr.— A genus of In-
fusoria, family Monadina, E.

Char. Tail absent ; body truncated in
front, with a single flagelliform filament ;
one or two red eye-spots present. Fresh-
water.

Probablv the spores of Algae.
M. punkifera (PL 31. fig. 43a). Body
yellow, ovate, subconical, attenuate poste-
riorly, two red eye-spots accompanied by
a blackish frontal spot ; length 1-620".

M. monadina (PL 31. fig. 436). Body
ovate, equally rounded at both ends, bright
green ; eye-spot red and single ; length
1-1150 to 1-020".

BiBL. Ehr. Infus. 25 ; Kent, Inf. 403.
MICROGONID'IA. See Macrogoxidia.
MICROGRO'MIA, Hert.— A genus of
ReticiUarian Rhizopoda. The pseudopodia
of different individuals unite, so as to pre
duce colonies.
X. Slip pi. 1.)

(Her twig, Arch. mile. An.

MICROTI ALO' A, Kiitz.— A genus of Pal-
melLicea; (Confervoid Alga;), consisting of
microscopic gelatinous patches, floating in
water, crowded with minute green gonidia.
M. Ichthyohlabe (quite distinct from Cla-
THROCYSTis) occurs in IMtain ; and Has-
sall's Sorospora virescetis belongs here. Pro-
bably a Chhrococcus.

BiBL. Kiitz. Sp. Alfl. 207; Tab. Phyc.
pis. 6, 7 ; Ilassall, Alg'. 326 ; Rabenh. Aly.
iii. 60.

MICRO'MEGA, Ag., = Schizonema pt.

MICROM'ETER. See Introduction,
p. xxviii, and Measurement.

MICROBE Pt A, Lev.— A genus of Sphjs-
ronemei (Stylosporous Fungi), of which
one species is described as British, M. dru-
pacearum {Cenanyium Cerasi, junior, Fr.,
Spha>ria dubia, Pers.), growing on dead
branches of the cherry-tree. It forms
whitish tubercles which split the bark trans-
versely, composed of somewhat cylindrical
conceptacles, conjoined at the base, the
white mealy ostiole projecting; the linear
spores are yellowish and curved at the
apex.

BiBL. Berk, and Broome, Ann. N. IT.
2 ser. V. 380 ; Leveille, Ann. Sc. Nat. 3 s(5r.
V. 283 ; £r. Flora, ii. pt. 2, 211.

mCROP'ORA, Gray,= Membranipora
pt. (Hiucks, Polyz. 173.)

MICROPOREL'L A, Ilincks, = Lepralia
pt. (Hincks, Poh/z. 204.)

MI'CROPYLE (of Animals). See Ovum.

MICROSCOPE.— The first Section of
the Introduction consists of remarks upon
the microscope and microscopic apparatus.

MICRO-SPECTROSCOPE. See Spec-
troscope.

MICROS'PORA, Thuret,= Conferva pt.

MI'CROSPORES.— The small kind of
spores produced by Lycopodiacete and Mar-
sileacese in contradistinction to megasporea
or macrospores. When sown, they pro-
duce sperm-cells and spermatozoids.

MICROTHAM'NION, Niig. — A genus
of Chaetophoracese.

Char. Filaments much branched, rigid,
jointed, narrow; joints longer than broad,
slightly tumid. Propagation by zoogonidia.
Freshwater.

BiBL. Rabenh. Alg. iii. 365.

MICROTIIE'C A,"Ehr. —A marine organ-
ism of doubtfid nature.

It consists of yellow, flattened, rectan-
gular (side view) bodies, with four equi-
distant spines projecting from each end;
the colour arises from the contents ; no

mCROZYMES.

[ 504 ]

MILLOX'S TEST.

transverse line of division; entire length
1-216".

BiBL. Ehr. Infus. 164.

MI'CROZYMES, B(5chanip.— The term
applied to the minute particles or organisms
producing fermentations, especially the
pathogenous. Most of these bodies are
considered to be forms or spores of Schizo-
mycetes, referable to the genera Bacterium,
Bacillus, and Micrococcus. Being very
minute, they are with difficult}- separated
from the other constituents of the liquids
in -which they occur; and the process
adopted by Chauveau and Sanderson to
isolate and prove the action of the vaccine
microzymes may be pointed out. Tlie
vaccine matter was placed in a very small
test-tube, a Httle water gently added. The
layer of leucocytes AA-hich subside first, was
separated, and on vaccination found to be
inactive. The remaining liquid was allowed
to stand, when the soluble albuminous con-
stituents diffused into the water, but the
solution was innocuous ; the zymome-layer
was however found to be active.

BiBL. Bechamp, Coinp. rend. 1S68, Qu.
Mic. Jn. 1868, 274 ; Sanderson, Priv}i Coun-
cil Hep. 1869, 232 ; Ilallier, Phijfopafhol.
1868; Roberts, Q. M. Jn. 1877, xvii. 307;
Klein, Qu. Mic. Jn. 1878, xviii. 170.

MIELICHHOFE'RIA, Ilornsch.— A ge-
nus of Bryaceous Mosses, containing one
British species, il/.M«V/f/«, sometimes referred
to Weissia (fig. 81, p. 121).

MILI'OLA, Lamarck. — An extensive ge-
nus of Imperforate (Porcellaneous) Fora-
minifera, in which the chambers grow alter-
nately on two or more sides of the long
axis of the suboval shell : if on two sides,
they iorm Biloculina (B. rinc/ens, PI. 23. fig. 3)
and Sj)iroloculina(Sp.planulata, PL 23. f. 7),
many and thin in the latter, few and thick
in the former ; if on three sides, they form
Triloculina (Tr. triyonula, 1*1. 23. fig. 4). Ir-
regular development of the edges of the
chambers gives rise to the many Quinque-
loculine varieties {Quinqueloculina seminu-
hnn, PL 23. fig. 5; (}. Brunpiiarfii, fig. 0) —
from three to eight cliambers being visible
on one side, and from two to six on the
other. Uniloculina ( U. inclica, PL 23. fig. 2)
is possibly a young or arrested MilioJa.
Cruciloculina has a cross-slit opening, whilst
the others have usually a crescentic aper-
ture, owing to the presence of a tongue
(homologue of the septum); but it may bo
round and produced.

In its young or Adelosine stage, Miliola

differs fi'om Cornu^spira by its segmental
stricture. See M. obesa junior, Schultze,
PL 23. fig. 1. Hai-erixa and Fabul.\ki.\
are closely allied genera.

Fossil in all formations from the Trias
upwards ; and common in existing seas,
chiefly in shallow water (M. seminulum,
PL 23. fig. 5).

BiBL. Williamson, ^^'c.Jbr. 78; Schultze,
Org. Polyth. 67; Parker, Tr. Mic. Sac,
n. s. vi. 53 ; Parker & Jones, Ann. N.
If. 2, xix. 299; Cai-penter, Introcl. For.
74.

MILK. — This liquid consists of a solu-
tion of caseine and certain salts, holding in
suspension minute glubules of fatty matter
(butter).

The fluid portion possesses no microscopic
peculiarities. The globules are very nume-
rous, round, and vary in size from mere
molecules to 1-3000 or 1-2O0O" in diameter.
Each is surrounded by a pellicle or coat of
caseine, which prevents the globules from
fusing into each other. If a portion of a
drop of milk be placed upon a slide, and the
thin glass cover be moved to and fro, the
coat of caseine will be ruptured, the globules
of oil will become confluent, and shreds of
the coats will be visible. If acetic acid be
added, the coats will be acted upon, and the
confluence also produced. The same effect
occurs naturally in sour milk ; hence in this
the globules are often much larger than the
above dimensions, and irregular in form,
frequently becoming elongated and united
in twos, so as to bear some resemblance to
the young state of a fungus.

The milk first secreted after parturition,
called the colostrum, differs considerably
from the normal liquid. The fatty globules
contained in it vary greatly iu size, often
being \evj large, and existing within iso-
lated or aggregated epithelial cells, some of
them resembling exudation-corpuscles.

Peddie's paper on the human milk in
relation to medical practice, is well worthy
of perusal.

BiBL. Kcilliker, Mik. An. ii. ; Donu^,
Cours de Micros. ; "Wagner, Hand. d. Phy-
siol, art. Milch ; Peddle, Ed. Mn. Jn. 1840,
and Chemistry.

MILK- VESSELS. See Laticifeeous

TISSUE.

MILLON'S TEST, or TEST-LiQrro.—
Tliis is a strongly acid (nitric and nitrous)
solution of proto- and peruitrate of mercury,
made by dissolving metallic mercury in its
weight of strong nitric acid, with the aid of

MILNESIUM.

[ 505 ]

MNI0IDE.15.

hoat. It gives a red colour to certain sub-
stances, gently boiled in it.

The followinp: substances and tissues are
coloured red by the test : albumen, caseine,
chondriue, crystalline, epidermis, feathers,
fibrine, gelatine, gluteu, horn, legumine,
proteine, silk, wool.

The follo^viug, when pure, are not co-
loured : cellulose, chitine, cotton, gum (ara-
ble), linen and starch.

BiBL. Millon, Coinpt. Rend. 1849, or
Chem. Gaz. 1849, vii. 87.

MILNE'SIUM, Doyere. — A genus of
Arachnida, of the order Tardigrada (Oolo-
poda).

Char. Head with two very short palpi-
form appendages at its anterior and lateral
parts ; mouth terminated by a sucker sur-
rounded by palps ; skin soft, transversely
furrowed ; legs four pairs ; rings of the body
divided into two segments.

M. tardiyradum (PI. 50. fig. 9). Mouth
surrounded by six minute unequal palpi,
svmmetrically arranged, diminishing in size
from the upper to the lower part; head
rounded in front when the mouth is re-
tracted ; eye-spots tolerably large and gra-
nular; pharyngeal tube much dilated, styles
very small, bulb elongated and pyriform,
without an internal framework ; body trans-
parent, attenuated at both ends, especially
the posterior ; skin pale brownish yellow ;
three anterior pairs of legs nearly equal, the
foiu'th very short, resembling two tubercles,
with scarcely a trace of annulif orm division ;
claws four, two terminal, and in the form of
elongated filaments hooked at the end, and
each supported on a distinct tubercle ; two
inferior and internal, the anterior divided
into three strongly curved hooks, the pos-
terior into two ; hooks or terminal filaments
of the fourth pair longer than those of the
first three. Movement active. Length
1-50 to 1-40".

BiBL. Dovere, Ann. Sc. Nat.
MIMOSEL'LA, Hincks.— A genus of
Ctenostomatous Polyzoa, fam. VesiculariidaB.
Char. Zoary confervoid, jointed, and
branched ; cells ovate, opposite, with a basal
joint; animals with eight tentacles and a
gizzard.

M. gracilis. Branches erect, arising from
a creeping fibre. On sea-weeds.
BiBL. Hincks, Polyz. 555.
MINERALOGY, application of the
MICROSCOPE TO. — The following substances
mav bo recognized in transparent minerals
or blowpipe beads, by means of the cha-

racteristic absorption-bands seen in the
spectrum, even when they are much co-
loured by the oxides of iron, manganese, or
nickel, viz. didymium, erbium, uranium,
cobalt, chromium, copper, manganese, and
jargonia. In one method the substance is
fused with borax or microcosmic salt, so as
to give a clear bead, and the spectrum is
examined by means of the spectrum eye-
piece. In the other method, the saturated
borax bead is kept hot over the lamp, so
that crystals may be deposited in it. Many
kinds of crystals may be thus distinguished.
See Spectroscope and Rocks.

BiBL. Sorbv, Qu. Mic. Jn. 1869, 182.

MIRROR "OF SCEMMERING. See
Introduction, p. xxii.

MISCHOCOC'CUS, Nag. A genus of
Palmellaceae.

Char. Thallus gelatinous, branched ; the
terminal cells of the branchlets in pairs or
fours. In boggy pools.

M. confervicola (PI. 52. fig. 12).

BiBL. Rabenht. Fl. Alt/. Eur. iii. p. 54.

MISTLETOE. See Viscum.

MITES. — The animals usually included
under this term are species of Acarina.

MITOPH'ORA,Perty.— A genus of Ciho-
Flagellate Infusoria. Free, ovate, with a
lateral row of parallel stout cilia, and a long
terminal flagellum. M, duhia, fi-eshwater.
(Perty, Lehens. 15.3.)

MNIA'CE^.— A tribe of Mnioide^
(Mosses), of Bryoid habit, but with firm,
rigid, and usually undulated leaves, mostly
increasing in size toward the top of the
stem. British genera : Cinclidium, Geor-
gia., Mnium, and Timmia.

MNIADELPHA'CE.E. — A family of
Pleurocarpous Mosses, with the leaves ar-
ranged in four or more series, and composed
of parenchymatous cells, mostly equally
hexagonal and Mnioid, very smooth, pellu-
cid, destitute of a distinct primordial utricle,
the lowest decurrent on tlie stem at the base,
larger, spongy, lax, mostly beautifully dark-
tinged, never single, slender. Brit, genus:

I)altonia. Calyptra mitre-shaped, bell-
shaped, elegantly fringed at the base. Pe-
ristome double [Neckeroid) : outer, sixteen
narrow, subulate, trabeculate teeth, reflexed
when moistened; inner, an equal number
of similar cilia, alternating with the teeth,
devoid of a basilar membrane.

MNIOI'DEvE.— A family of operculate
Mosses, ordinarily of acrocarpous habit, but
sometimes pleurocarpous, with broadl}' oval,
spathulate, oval or lanceolate, flattish leaves,

MNIUM.

[ 506 ] MOLECULAR MOTION.

having a very prominent, thick dorsal nerve.
The base of the leaves composed of some-
what parallelogrammic cells, rounded-hexa-
gonal or with equal walls towards the apex,
very full of chlorophyll, or with the pri-
mordial utricle mostly very conspicuous, or
much thickened, firm, rarely papillose. This
family is divided into two tribes : Mnia-
CE.^i; and Polytrichace^.

MNI'UM, Dili. — A genus of Mniaceous
Mosses, of acrocarpous and pleurocarpous
habit, including many Brya of the British
Flora. Among the commonest is M. hor-
nu7n = Bnium hornum, L.

MOCHA STONES. — The varieties of
chalcedony known under this name contain
a number of bodies (mineral dendrites)
which have been mistaken for plants.

Compare Agate, Silica, and Flint.

BiBL. K. Miiller, Ann. N. H. 1843, xi.
41o.

MOH'RIA, Swartz. — A genus of Schizae-
aceous Ferns.

M. tlmrifraga (fig. 4G0) ; Cape. (Hook.
Syn. 436.)"

IMohria thurifraga.

A pinnule with Bporangea.

Magnified 25 diameters.

MOI'NA, Baird. — A g«nus of Entomos-
traca, order Cladocera, and family Daphni-
adse.

Char. Head rounded and obtuse ; supe-
rior antennas of considerable length, of one
piece, and arising from the front of the head
near the middle ; inferior antennae large,
fleshy at the base, and two-branched, one
branch three-jointed, the other four-jointed ;
legs five pairs. Freshwater.

M. rectirostris (PL 19. fig. 21). Cara-
pace almost straight or but slightly rounded
behind.

M. brachiata or hranchiata. Carapace
greatly rounded behind.

BiBL. Baird, Br. Entmnns. 100; Grobben,
Entw., Jn. Mic. Soc. iii. 77.

MOIST CHAMBER. — Introduced by
Recklinghausen, improved by Schultze and
others ; it enables the object under micro-
scopic examination to be placed in a space
saturated with moisture, and to be examined
without or with the inten-ention of thin
glass. Also it enables an immersion-lens to
remain with its water in contact with thin
glass over an object in any liquid for a con-
siderable time. The simplest form is that
of a large glass ring cemented to a broad
glass plate ; a thin and flexible caoutchouc
membrane is tixed to the ring and to the
object-glass by india-rubber rings. The
growing-slide mostly answers the same pur-
pose. See Frey, ^3Iik. 63; Rutherford,
Hist. 150 ; Dalhnger and Drysdale, M. M.
Jn. xi. 97.

MOLECULAR MOTION. — When ex-
tremely minute particles of any substance
immersed in water or other liquid are exa-
mined under the microscope, they are seen
to be in a state of vivid motion. A little
gamboge or Indian-ink mixed with water
will exhibit the phenomenon distinctly
enough. The minute particles or molecules
are seen to move irregularly, to the right
and left, backwards and forwards, as if re-
pelled by each other, until the attraction of
gTavitation ultimately overcomes the force
upon which their motion depends, when
they sink to the surface of the slide. This
applies to the molecules of those substances
which are heavier than water. In the case
of those which " are lighter than water, or
the liquid in which they are immersed, the
molecules ultimately become adherent to
the tliin glass covering the slide.

This motion is in no way connected with
evaporation, for it takes place equally when
this is completely prevented, just as when
it is not. Neither light, electricity, mag-
netism nor chemical reagents exert any
effect upon it. Heat is the only agent
which affects it ; this causes the motion to
become more rapid. Hence it might be
attributed to the various impulses which
each particle receives fi'om the radiant heat
emitted by those adjacent. Or, as it takes
place when the temperature is uniform, may
it not arise from the physical repulsion of
the molecules, uninterfered with by gravi-
tation, hence free to move ? The effect of
heat would then be explicable, because this
increases the natural repiilsion of the parti-
cles of matter, as in the cou version of water
into vapour.

Molecidar motion plays a part in some

MOLGULA.

C 507 ]

MONADINA.

common phenomena. Tlius, it prevents
turbid water from becomino- rapidly clear by
repose ; by its agency also the disaggregated
particles of animal or vegetable matter are
diHiised throughout the mass of the liquid.

The microscopist sliould become ac-
quainted with the appearance of particles in
molecular motion, as it might give rise to
error ; and it often occurs in animal and
vegetable cells. Thus particles under its
influence might be mistaken for monads ; or
particles moved by cilia miglit be regarded
as merely exhibiting this molecular motion.

Two circumstances appear most favour-
able for its production and continuance, in
addition to the augmentation of tempera-
ture, viz. a very iinely divided state of the
matter, and the specific gravity of the matter
and the liquid in which it is suspended being
as nearly as possible coincident.

BiBL. Brown, On Active Molecules {pri-
vateh/ pn'nfed) ; Duj. Ohserv. au Mic;
Grifiith, Med. Gaz. 1843 ; Delsaulx, M. Mic.
Jn. xviii. 1; Hartley, ib. 8j Jevons, Qu. Jn.
Sc. 1878, 167 5 Orel, Jn. Mic. Soc. 1879,
656.

MOL'GULA, Forbes.— A genus of Tuni-
cate Mollusca, of the family Ascidiad^^.

Two British species : M. oculatn, adherent,
bluish or purple, mottled with orange, 2-^" in
diameter ; and M. tuhulosa, free, in sand.

BiBL. That of the familv.

MOL'GUS, Duj ., = Bdella pt. 2 species ;
on marine sands. (Dujardin, VInstitut, 1842,
310; Gervais, ^^^^. 1.58.)

MOLLUSCA.— Every portion of the
structures of the Mollusca offers objects of
interest to the microscopist. The motion
of the cilia, the structure of the lining
membrane of the viscera, the spermatozoa,
the ovular growth and the nature of the
sensory organs can be easily investigated.
Remarks upon certain interesting structures
occurring in the Mollusca will be found
under Tongue, Shell, Snails (Water-),
Mussel, Oyster, and Ovusi. The calca-
reous concretions, crystals, and spicula met

with in the integument or mantle of some
mollusca are curious.

BiBL. Siebold, Vcrc/l. An. and the co-
pious BiBL. ; Vogt, Zool. Briefe ; Adams,
Recent Mollusca ; Forbes and Hanley, Br.
Mollusca ; Woodward, Shells ; Jones, An.
Kinr/dom, and Cycl. of An. and Phys. ;
Huxley, Comp. Anat., and Enyl. Cyclop. ;
Deshayes, Hist. Nat. Moll. ; Turton, Br.
Shells, by Gray ; Jeilreys, Br. Conch, (figs,
of all species, mar. and frw.) ; Rimmer, Br.
Id. and freshwater Shells.

MONACTI'NUS, Bail.— A genus of Des-
midiaceoe = Monactinium, Braun.

Distinguished from Pediastrum by the
marginal cells having one horn only.
Species : — M. octonariiis : marginal cells
eight, central none. M. duodenorius (PI. 36.
fig. 28): marginal cells twelve, central
three,

BiBL. Bailey, Smith. Contr. 1853, 14 ;
Rnbenh, Alg. iii. 71.

MONADLNA.— A family of Infusoria,
accoi'diug to Ehreuberg's system, but con-
sisting of a heterogeneous group of imper-
fectly examined bodies.

Char. Carapace absent ; no expansions ;
locomotive organs consisting of one or more
flagelliform filaments or cilia at the anterior
part of the body.

Ehreuberg distinguishes nine genera :

A. Tail none.

a. No lips.

a. Swimming.

a. No eye-spot.

Single 1. Monas.

Grouped 2. Uvella.

j3. Eye-spot present.
Single.
* I'lagelliform filaments

one or two 3. Microfflena.

** Fiagellifiirm filaments

four or five 4. Chloraster.

*** riagclliform filaments

numerous 5. Fhaceloinonat.

Grouped 6. Glenomorum.

b. Rolling 7. Doxococeus.

b. Lips present 8. Chilomonas.

B. Tail present 9. Bodo.

Duj ardin divides them thus :

A single flagelliform
filament

MONADINA.

f „-;„;„~ f„„™ ti t ■ f moving throuehout its whole length

arising irom the anterior l.i_- i i • j t ti ^ ui

,^i-„ .„t <•.!, 1 J 'thicker and rigid at the base, moveable
extremity of the body ' *'

1. Monas.

A second filament.

( at the end 2. Ci/cUdium.

^^ arising obliquely from behind an anterior prolongation 3. Chilomonas.

( lateral _ 4 Ainphimonas.

I posterior 5. Cerconiona.^.

Two equal filaments terminating the curved angles of the anterior end 6. Trepomonas.

Four equal filaments in front, and two thicker ones behind 7. Hexamita.

A second filament arising from the same spot as the flagelliform filament, but thicker,

trailing and retracting 8. Seferomifa.

^A filament and vibratile cilia 9. Trichomonas.

J Groups always free, revolving 10. UccVa.

j Groups originally fixed at the end of a branched polypidom or stalk 11. Anthophysa.

MONADS.

[ 508 ]

MONOCOTYLEDONS.

Dujardin's characters are : — animalcules
■without an integ-ument, consisting of a glu-
tinous, apparently homogeneous substance,
susceptible of becoming agglutinated to
other bodies, and so drawn out and altered
in form, with one or more flagelliform fila-
ments as locomotive organs, and sometimes
lateral or tail-like appendages.

BiBL. Ehr. Infus. 1 ; Duj. Infus. 270 ;
DaUinger, M. M. Jn. xiii. 185 ; Cienkowsld,
Schnitzels Arch. xii. 227.

MONADS are species of Monas, or other
Monadina.

MONAS, Miill. — A genus of Infusoria, of
the family Monadina.

M. Dailingerii. Ovate, pointed, no nucleus
nor contractile vesicle; length 1-4000". In
fish- (cod) macerations. Propagation by
transverse fission ; and by spores after con-
jugation and encystment. The germs of
these monads survive a temperatme which
destroys the adidts.

M. vhwsa, E. Ovate, uniformly rounded
at each end, of a red-wine colour, motion
slow and tremulous. Length 1-12,000 to
1-6000".

Foimd upon the sides of glass vessels in
which decaying vegetable matter has been
kept, on the side next the light.

M. lens, D. (PI. 31. fig. 44 a). Body
rounded or discoidal and tubercular. Breadth
1-5200 to 1-1800".

One of the most common organisms in
animal and vegetable infusions. We have
found one common in animal infusions
(PL 31. fig. 44 b), perhaps the same as the
above ; but it possesses usually two fila-
ments : on the left side is one without fila-
ments, but with the body drawn out from
adhesion to the slide.

M. altemiata, D. (PL 31. fig. 44 c). Body
ovoid, narrowed at the ends, nodular, un-
equal ; filament arising from the anterior
narrowed portion. Ijcngth 1-1 GOO". Very
abundant in fetid films floating on water
containing decaying freshwater Algse.

M. jyi-odif/wsa, see Micrococcus.

Several other species ; many probably
consisting of the zoospores of Algfe, or the
swarm-germs of other Infusoria.

BiBL. Ehr. I7ifus. S; Duj. Infus. 279;
Kent, Inf. 232.

MONE'RA, Haeckel.— A gi-oup of Pro-
tista, forming the simplest of all organisms,
the protoplasm or sarcode constituting the
whole structureless body ; nuclei and cell-
membranes are never developed. The Mo-
nera are subdivided into Gymnomonera and

Lepomonera, The Gymnomonera do not
pass into a quiescent or resting condition,
and do not surround themselves with a
covering, and propagate by fissiparous divi-
sion. The Lepomonera pass into a resting
stage, and surround themselves with a co-
vering for the purposes of reproduction —
breaking up into spore-like bodies, which,
on escaping, resemble the parent form.

BiBL. Cienkowski, Schultse's Arch. 1865,
i. 203 ; Haeckel, Zeit. loiss. Zool. 1865, xv.
360 ; Gejier. Morph. Jenai. Zeit. 1868, iv. ;
Wright, Qu. Mic. Jn. 1869.

MONOCER'CA, Bory.— A genus of Ro-
tatoria, of the family Hydatinsea.

Char. Eye red, single, cervical; foot-like
tail simply styliform.

Gosse mentions a second eye situated in
the breast of one species. Ehrenberg de-
scribes three species, to which Gosse adds
two.

M. rattus, E. (PI. 44. fig. 9). Body ovate-
oblong ; forehead truncate, unarmed ; foot
styliform, as long as the body. Aquatic.
Length 1-120".

BiBL. Ehr. Infus. 4:'2-2; Gosse, Ann. N. H.
1851, 199.

MONOCOTYLE'DONS. — One of the
classes of Angiospermous Flowering Plants,

Fiff. 461.

Reduced view of a stem of a Palm, showinjj the per-
pendicular and horizontal section, in which the fibro-
vascular bundles i\V are seen isolated in the medullary
parenchyma.

so called from the structure of the embryo
contained in the seed, which in a lar^ce num-
ber ot cases is of microscopic dimensions,
and always requires the use of the simple
microscope for its dissection. Some of the
families placed under this head have usually
an acotyledonous embryo, as Orchidaceas ;

MONOGRAMMA.

[ 609 ]

MONSTRILLA.

but these possess tlie character of the class
in all other respects. Auioug- the most im-
portant of their other characters is the iso-
lated condition of the fibro-vasciilar bundles
forming the woody structures (see Tissues,
vegetable). This character, mostly very
evident both in perpendicular and horizon-
tal sections of the stems, is illustrated by
figs. -loG & 401.

MOXOGRAM'MA, Schk.— A genus of
Grammitideae, consisting of small grass- or
rush-like plants, the simplest in structure
of all the Ferns. Several species, tropical.
(Hooker, Si/>iops. 374.)

MOXOL'ABIS, Ehr.— A genus of Rota-
toria, of the family Philodinaea.

Char. Eyes two, frontal ; tail-like foot
with two toes ; horns absent.

Two species.

M. gracilis (PI. 44. fig. 10). -Body slender,
no cervical process nor respiratory tube ;
teeth two in each jaw ; freshwater. Length
1-240 to 1-144".

BiBL. Ehr. Infus. 497.

MONOR'MIA, Berkeley.— A genus of
Nostochacese (Confervoid Algte), with a
definite, linear, convoluted frond, enclosing
a single moniliform filament ; differing from
Nostoc in the convoluted frond being devoid
of the common membranous pellicle. Mo-
nonnia infricata occurs in gelatinous
masses, about as large as a walnut, of a
reddish-brown colour, floating in slightly
brackish ditches. When the spermatic cells
are quite mature, the definite outline of the
linear frond is almost lost, and there is little
to distinguish the plant from Trichormus,
except the peculiar convolutions of the
moniliform filament : the frond then also
assumes a greenish tint.

BiBL. Berk., Glean, of Br. Alqce, t. 18 ;
Ralfs, Ann. N. H. ser, 2. vol. v. pf. 8. fig. 1 ;
Harvey, Phyc. Br. t. 2-56 ; IlassaU, Algce, i.
75. fig. 11. Nostoc intriccdum, Meneghini,
Anahcsna intricata, Kiitz., Tab. Phyc, i. t. 94.
fiff. 1 : Rabenhor.st, Ahj. ii. 183.

''MOXOSI'GA, Kt.— A genus of Choano-
flageHate Infusoria.

Char. Bodies naked, solitary, sessile or
stalked, with a single tiagellum, and an an-
terior funnel-shaped collar composed of sar-
code. Nine species, freshwater and marine ;
1. 1-5000 to 1-2.500". (Kent, Infus. 329.)

MOXOSPI'LUS, Sars. — A genus of
Lynceidfe (Entomostraca).

Char. Carapace of series of superimposed
valves ; head depressed ; no compound
eye.

BiBL. Norman and Brady, Mon. Nat.
Hist. Tr. Northumb.

MONOSTE'GIA, D'Orb. ; MONOTHA-
LA'MIA, Schidtze. — Instituted as an order;
but one-chambered Foraminifera are found
in most of the chief families, and therefore
cannot constitute a separate group. Thus
Proteonina, Squamidina, Cornuspira (PI. 23.
fig. 13), Vniloculina (PI. 23. fig. 3), Tro-
chammina (PL 23. fig. 14), Saccammina,
Astrorhiza,Laffena (PI. 23. figs. 22-27), Ovu.-
lites, Orbulina (PI. 24. fig. 1), and SpirilUna
(PI. 24. fig. 5) are either usually or constantly
unilocular.

MONOSTRO'xMA, Thuret.— A genus of
Ulvaceae (Confervoid AlgsB), of which M.
buHosum (U/va bullosa, Roth) is the type,
distinguished from Ulua by consisting only
of a single layer of cells, and these being
roundish (mostly grouped in fours), im-
bedded in an apparently homogeneous ge-
latinous membrane (PI. 9. fig. 1 a). This
plant is reproduced by zoospores formed
from the cell-contents, and discharged by
bursting of the cell-wall (fig. 1 b, c). They
have four cilia.

Currey has described, under the name of
M. roseum, a plant which we think scarcely
referable here, but rather to Microcystis.

BiBL. Thuret, Ann. Sc. Nat. 3 ser. xiv.
225, pi. 21. iigs. 1-4 ; id. Mem. Soc. Scient.
de Cherbonrq, ii. 1, 1854.

MONOSTY'LA, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eye single, cervical ; tail-like foot
simply styhfoi-m ; carapace depressed.

Four species : three, Ehreuberg ; and one
other, Gosse.

M. quadridentata (PI. 44. fig. 11). Cara-
pace yellowish, fore part of head deeply
cleft in fom- horns; freshwater. Length
1-120".

BiBL. Ehr. Infus. 459; Gosse, ^nn. N.H.
1851, viii. 200.

MONOTOS'PORA, Corda.— A genus of
Dematiei (Hyphomycetous Fungi), of which
one species has been found in England,
growing on dead bark of the yew. M. me-
galospora, Berk, and Br. Filaments erect,
simple, straight, nearly equal, articulated.
Spores tei-minal, obovate, even, -00133 to
■0014" long. Frie^ regards this genus with
doubt.

BiBL. Berk, and Broome, Ann. N. H.
2 ser. xiii. 462, pi. 15. fig. 11 ; Fries, Sum.
Veg. 497.

MONSTRIL'LA, Dana. — A genus of
Copepodous Entomostraca. M. Any/ica;

MONTAGNITES.

[ 610 ]

MOSSES.

Wevmouth. (Lubbock, Ann. N. IT. 1857,
XX. 401 ; Brady, Cop. iii. 37.)

MONTAGNI'TES, Fr. — A genus of
Agaricini (llymenomycetous Fungi), distin-
guished by the dry gills which project after
the universal volva breaks off from the
edge of the pileus.

One species occurs in the south of France
and Algeria, another in Texas, and a third
in Siberia, in dry sandy soil; extremely
interesting as connecting the Hymenomy-
cetes with the Gasteromycetes.

BiBL. Fr. JSp. 241 ; FL Alg. t. 21. f. 2.

MONU'RA, Ehr.— A genus of Rotatoria,
of the family Euchlanidota.

Char. Eyes two, frontal ; foot simply sty-
liform. Carapace somewhat compressed
and open beneath.

Two species.

M. duk'is (PI. 44. fig. 12). Carapace
ovate, obliquely truncate and acute behind ;
eyes distant. Length of carapace 1-280".

BiBL. Ehr. In/us. 474.

MOOR'EA, J. & Kirkby.— A fossil Os-
ti'acode, known by its suboval depressed
valves, with raised margins. Found in
Silurian and Carboniferous rocks.

BiBL. Jones & Holl, Ann. N". H. 4, iii.
225

~ MORCIIEL'LA, Dill— A genus of Asco-
mycetous Fungi, distinguished by its stipi-
tate receptacle, wliich is deeply folded and
pitted.

Four species occur in this country, amongst
which M. crassipes is the giant of the genus.
The species are esculent, and largely im-
ported. They are very abimdant in some
parts of India, especially in Kashmir. They
often occur on cinder walks and burnt S(iil.

BiBL. Grev. Cn/pt. Fl. tab. 68, 89; Berk.
Outl. t. 21. f. 5 ; Cooke, Handb. 655.

MORPHIA. See Alkaloids, p. 31.

MORPHO, Fabr.— A genus of Exotic
Lepidopterous Insects.

M. Mendaus. The scales from the wings
of this beautiful insect are sometimes used
as Test-Objects.

MORTIEREL'LA.— A genus of Muce-
dines, with branched threads like a cande-
labrum, on the underside of which spo-
rangia are produced ; zygospores have also
been found. Moulds of great elegance.
Martensella, an allied genus, has pectinate
sporangia. (Coemaus, liidl. Ac. Bclfiii[. xv.
544 ; Bary .fe Worouiu, Beit. 4 ; Brefeld, iv.

"mosses, MUSCACE.E.— This order of
flowerless plants is distinguished from the

Hepaticse by the vegetative structure and
by the sporanges. In one group alone
{Ilypopferyc/iece) is the stem clothed with
leaves, accompanied by amphigastria (sti-
pule-like leallets), in 'the manner of the
foliaceous Hepaticse (fig. 35o, p. 409) : and
here the sporauge is a stalked urn-shaped
body, with a deciduous lid, and Hke those
of the Mosses generally ; and this Jun-
germannia-like leafy stem is erect, and not
procumbent as in Jungermannia itself. In
all other Mosses the leaves clothing the
stem are arranged in a spiral order around
the stem, so as to give the vegetative struc-
ture a very characteristic aspect. On the
other hand, the AndraBacese, which have
a valvate capsule, have spirally-arranged
leaves.

The stem of the Mosses is a slender
thread-like wiry structure, wholly com-
posed of cellular tissue, without vessels ; but
the external layer has an epidermoid cha-
racter, while the central portion is com-
posed of elongated cells. In one section of
the Mosses this stem terminates in a spo-
range, and these are called Acrocarpous
Mosses; in others the sporanges spring from
lateral branches, and the ter-
minal bud of the stem elon-
gates the stem year after year;
these latter are called Pleiiro-
carpotis Mosses. In some of the
genera the sporanges are borne
terminally on short special
branches, as iii Sp/uu/num,
Mielichhoferia, part of Fisd-
dens, Guemhi'lia fontinaloides
(tig. 289, p. 366) ; these are
termed Cladocarpous.

The leaves are of simple
structure, usually composed
of a single layer of cells, the
forms of which are used as
characters by systematic Mus-
cologists. They are either all
alike in a leaf, and tilled with
chlorophyll, and in these cases
may be either jMrenchymatoKS Magn. 6o diamg.
(PI. 47. fig. 19) or prosenchy-
matoiis (PL 47. fig. 20). In other cases two
soi'ts of cells occur arranged in a peculiar
way ; some, smaller, containing chlorophyll,
form a kind of network, the meshes of which
are occupied by large nncoloured cells (see
Sphagnum and Leucohryum).

The margins of the leaves are frequently
st>rrated ; and the upper surface is occasion-
ally papillose, or covered with rough points.

Fig. 462.

Ephomprum

serratum.

Leaf.

MOSSES.

[ 511 ]

MOSSES.

Many of them have one or more distinct
nervules, composed of elongated cells, often
not reaching the apex of the leaf.

The leaves oftvn differ on different parts
of the stem ; and we hence have radical,
cauline, &n^ perichcetial or involucral leaves,
the last ordinarily f n-ming a kind of rosette,
in the midst of wliich the reproductive or-
gans are produced. Schistostega exhihits
two forms of stems, with two kinds of folia-
ceous structure : tlie stems which terminate
in a sporange have leaves only at the upper
part, and these arranged in eight rows
standing crosswise on the stem, like ordi-
nary leaves ; the barren stems have two
rows of leaflets arranged in one plane on the
stem, like the leaflets of a compound leaf
(such as that of the Acacias) of Flowering
plants. The stem-leaves of many genera
exhibit wing-like structures, hair-like ap-
pendages, i)V peculiar forms of curvature
(figs. "242-246, Fissidens) ; others, like

Fig. 4G3

Barbula L-hloronotus.
Fig. 463. Leaf with Cfllular filaments at the tip. Magn.

30 diams.
Fig. 464. Leaf with cellular filaments crowded on the

midrib, with an awn-like prolongation.

Magn. 20 diams.

certain Barhulce (figs. 40.3-466), have col-
lections of cellular filaments on the upper-
side.

The outer leaves surrounding the repro-
ductive organs are called perichcetiaJ, and
sometimes 'they form the only envelopes ;
sometimes, however, a few small leaves,
difiering very much from the above, form
the immediate envelopes of the archegones ;
and these pen(/omal leaves, forming the
perigone, are developed after the reproduc-
tive organs themselves (as is the case also

with the perigone of the Hepaticse). The
perigonial leaves either overlap and cover-in
the reproductive organs, or they are keeled
at the base and turned liack above, so as to
expose the organs of reproduction (PoLY-
triciium).

The Mosses have no roots, their function

Fig. 465.

Fig. 466.

Barbula chloronotus.

Fig. 465. Cross-section of 463. Magn. 50 diams.
Fie. 466. Cross-section of 464. Magn. 50 diams.

Fig

being performed by root-hairs or rhizoids,
usually brown.

The young reproductive organs_ consist
of antheridia, and archcgonia or pistillidia,
which are found either together (fig. 467),

Fi?. 467,

Fig. 468.

Bryum nutans.

Fig. 467. Inflorescence of antheridia and arohegonia.

Magn. 25 diams.
Fig. 468. Spermatozoids from antheridia. Magn. 600

diams., the cilia omitted.

or on different parts of the same plant, or on
diflerent individuals of the same species.

Fig. 469.

MniuBi arcticiun,

Antheridial inflorescence.

Magnified 25 diameters.

To these structures the term inflorescence is
applied. The antheridia occur either with
the archegones in one perigone (fig. 467) or

MOSSES.

[ 512 ]

MOSSES.

in the axils of the upper leaves of the stem,
which terminates in a perigoue containing
archegones ; or they have a special perigone
(fig. 469), either on the same plant, or on a
different one fi-om that which bears the
archegones. The antheridia are globular,
oval (fig. 467), or elongate membranous
sacs composed of cellular tissue, red or

Fig. 470.

Fig. 471.

Fig. 472.

Fig. 473.

Fig. 470. Cosoinodon pulvinatus. Capsule enclosfd in

the calyiitra, with the Yaginule below.

Magn. 10 diams.
Fig. 471. Orthotrichum Hutchinsii. Capsule covered

by the calyptra, with the vaginule below.

Magn. 10 diams.
Fig. 472. Ditto. Calyptra, Magn. 25 diams.
Fig. 47l>. O. Btramineum. Vaginule. Magn. 25 diams.

yellow when ripe, filled with minute cells)
which escape by the bursting of the apex
of the sac ; and these cells exhibit a fiore
coiled in their interior, which circulates
rapidly, even before the expidsion from the
antheridium, and after a time breaks out of

its cell (fig. 468, and PL 40. fig. 33), and
moves rapidly in the water under the mi-
croscope (see Antheridia). The anthe-
ridia are generally accompanied by cellular
filaments which have received the name of
parapht/ses (fig. 23, p. 57); no physiological
office is attributed to these ; but "the anthe-
ridia are the male organs.

The ai-chegone of the Mosses (figs. 30, 31
(p. 71), 467), like that of the Hepaticee
(excepting Anthoceros), is a flask- shaped
cellular case, the epigone, containing an
emhi-yoncd cell at the bottom of its cavity.
This embryonal cell becomes gradually de-
veloped by cell-division into a conical "body
elevated on a stalk, which at length tears
away the walls of the flask-shaped epigone
by a circular fissure, and carries the upper
part upwards as a hood, while the lower
part remains as a kind of collar round the
base of the stalk (figs. 470-472) ; the latter
is termed the vaginula (fig. 473) ; the cap-
like portion carried upwards on the spo-
rauge is called the calyptra (figs. 470-472).
The sporanye, elevated more or less by the

Fig. 474.

Fig. 475.

Fig. 474. Tayloria serrata. Dimidiate calyptra. Magn.

2.5 diams.
Fig. 475. Funaria hj-grometrica. Section of young

capsule, showing the columella. Magn.

50 diams.

development of its stalk (seta or peduncle),
is gradually converted by internal changes
into a hollow urn-like case, usually -n^th a
stalk-Hke column (columella) running up
its centre (figs. 50, 475), the space between
the central column and the side walls be-
coming filled with free spores, which are
minute cells with a double coat, the outer
of which exhibits elegant markings (see
Si'OBEs). In some cases this hollow case
does not burst natiu'ally, but the spores

MOSSES.

[ 513 ]

MOSSES.

escape by its decay (Astomtjm, fig. 50).
In the ANDn^BACK-E (%. 11, p. 41) the
sporange bursts by vertical slits, so as to

Fig. 476.

Fig. 477.

n iriOt )■,'; j ,-i^!t! nciciS

Fig. 47ti. Cosetnodon pulrinatus. Fragment of peri-
stome. Magn. 100 diams.

Fig. 477. Barbula flavipes. Fragment of peristome.
Magn. 100 diams.

be divided into valves, as in the Junger-
jnanniese, and there is no column in the
sporange here ; but the valves do not sepa-
rate at their suuimits, and the character of
the leafy stem at once distinguishes these

Fig. 478.

Fig. 478. Phasciun serratum. SeFsile sporange enclosed
by few leaves. Magn. 1.5 diams.

Fig. 479. Pottia truncata. Operculum separating from
the sporange. Magn. 10 diams.

Mosses from the Hepatica?. The ordinary
course, however, in the Mosi^es is the fonna-
tion of a horizontal slit ner r the top of the

sporange, so that the upper part falls off like
a lid (operculum, fig. 479).

The sporange of the Mosses exhibits a
very complex anatomical structure, which
we have not space to enter into veiy mi-
nutely : it will suffice to state that the
lower part next the peduncle is sometimes
enlarged into a thickened mass, called the
apophysis ; sometimes the peduncle is very-
long, sometimes very short (P/mscunz, fig.
478), so that the sporange is hidden in the
perichsete ; finally, the mouth may either
exhibit a smooth edge (fig. 479), or a single

Fig. 480.

^UX

Cinclidium arcticum

Part of double peristome, the inner processes united
into a plaited membrane in the centre.

Magnified 100 diameters.

(figs. 476, 477) or double (figs. 483, 484)
fringe of very variously constructed teeth,
which are of great service in discriminating
the genera. When the mouth of the spo-
range is naked, the Mosses are called ffym-
nostomous, when furnished with only a
.single row of teeth huploperistomous. When
a double peristome exi.^ts, the outer con-
sists of teeth, the inner of processes or cilia
(fig. 483) or of both {Bryiim). The teeth
sometimes arise , directly from the mouth of
the sporange, sometimes are seated on a
basal membrane, sometimes connected to-
gether irregularly (Funabia, fig. 259, p.
342), or by regular bars (Guembklia, fig.
291, p. 366), or the whole of the inner circle
may be conjoined entirely (Buxbaumia,
fig. 93, p. 126) or at the tips (fig. 480) into
a membrane, or by a number of cross bars
into an open trellis (fig. 484). The outer
rows of teeth are continuations of the inner
layers of tissue of the sporange (fig. 481) ;

2l

MOSSES.

[ 514 ]

MOSSES.

where an inner circle occurs they are con-
tinuations of the spore-sac ; the outer waU
of the sporange is, as it were, continued by
the operculum. Ordinarily these do not
separate directly from each other when the
lid falls off, since one or several layers of
elastic cells, forming a ring {annulus, lig. 482)
round the mouth, split out from between
the sporange and its lid, and cause the latter
to fall off.

The spores are developed in a distinct
spore-sac, which has one layer next the wall
of the capsule, and an inner layer next the

Fijr. 481.

Fig. 482.

Fig. 483.

Fig. 481. Racomitrium faaciculare. Section of margin
of sporange, with a tooth of the peristome.
Magn. lOU diams.

Fig. 482. Bryum CEespiticium, annulus. Magn. ICO diams.

Fig. 483. Orthotriehum diaphanum. Portion of double
peristome, the outer composed of teeth,
the inner of cilia. Magn. 50 diams.

Fig. 484,

Neckera antipyretica.
DonWe peristome, the inner composed of teeth united
by cross bars, forming a trellis.

Magnified 100 diameters.

columella. The top of the columella ex-
pands into a kind of pseudo-operculum in
Polytrichum. In Phascacese the columella
is absorbed.

Allusion has been made to the sexual im-
port of the antheridia and archegonia. In
the reproduction of the Mosses the spores
produce a confervoid filament or protonejna,
from the sides of which the young plants
with stem and leaves shoot ; and on these
the antheridia and archegonia are formed.
From the embryo-ceU of the fertilized
archegonium arises the sporogonium, in
which the spores are formed.

The Mosses exhibit a variety of forms of
vegetative multiplication. The lower part
of the stem often sends out horizontal
branches, which root and produce buds
(fig. 485) , from which arise new leafy stems ;

Fig. 485.

Polytrichum undiilatum.

Creeping filaments with innovations.

Magnified 5 diameters.

and in this way, patches of moss frequently
increase to a great size.

They also produce confervoid filaments,
which exhibit tuberous thickenings, a form
of gemma' (figs. 488, 480), which may be
detached from each other like bulbils, so as
to propagate the plants without any sexual
reproductive organs.

The protoplasm of these confervoid fila-
ments also foi'nis Amoeboid bodies, and
gonidia or ciliated zoospores (Flicks).

Gemm^ or minute cellular tubercles,
capable of development into new plants,
are likewise met with in other situations,
as in the axils of leaves, on the surface, the
margins (fig. 490), or at the tips (figs. 486,
487) of the leaves or the' stems (fig. 401):
these are formed of only a few cells at tlie
time they fall off, and illustrate well the

MOSSES.

[ 515 ]

MOSSES.

Fig. 486.

Fig. 487.

Orthotrichum phyllanthum.

Leaves with gemmae at the tips.

Magnified 25 diameters.

independence of the individual celh forming
the organs of these plants, where, under
peculiar circumstances, a single cell of the
tissue may be developed so as to lay the
foimdation of a new plant.

In the following arrangement of the
Mosses we follow Miiller. The order Mus-

cacefe is fii-st divided into two suborders
according to the habit of growth :

ACROCARPI. Mosses with the fruit-
stalk terminating the stem, or short special
branches (Cladocarpi).

PLEUROCARPI. Mosses with the fruit-
stalk produced only from lateral buds.

Si/nojJsis of the Families.
ACROCARPI.

* Schistocarpi. Cajjsule loithout a lid
(opei-culmn), opening by longitudinal
jfissures.

ANDHjEACEiE. Capsule splitting into
four valves.

** Cleistocarpi. Caps^ile without a lid,
hurstiiig open irregularly.

Bruchiace^. Cells of the leaf (areola-
tion) parenchymatous, looser at the base,
not papiDose, dense.

Phascace^. Areolation of the leaf
parenchymatous, dense, filled with chloro-
phyll, more or less papillose.

Epheiieee^. Areolation of the leaf
parenchymatous, everywhere lax, not papil-
lose.

Fig. 488.

Fig. 490.

Fis:. 491.

Hedwigia ciliata.

Creeping filaments with tuber-like gemmae.

Fig. 488, magnified 50 diameters.

Fig. 489, magnified 20 diameters.

Fig. 490. Orthotrichum Lyellii. Leaves with mar-
ginal gemmse. Magn. .50 diams.

Fig. 491. Aulacomnium undulatum. Gemmae in. tl e
place of the capsule. Magn. 20 diams.

2l2

MOSSES.

[ 51-6 ]

MOSSES.

*** Stegocai*pl. Capsule bursting hy a lid.

Distichophylla. Leaves arranged in two
straight rows.

a. leaves regularly vertical.
SCHISTO STE GE^ .

6. Leaves regularly subvertical.

Dbepanophylle^.

c. Leaves horizontal.

DiSTiCHiACE^. Areolation of the leaves
pareuchymatous, minute ; leaves wilhout
appendicular laminte.

FissiDENTE.E. Areolatiou of the leaves
parenchvmatous ; leaves produced into ap-
pendicular laminae at the back and point.

Polystichophylla. Leaves arranged in
three or more straight alternating
rows.

a. Leaves exhibiting narrow green cells, forming a reti-
culation between larger diaphanous cells.

Leucobbyace^. Leaves composed of
several layers of columufir, empty, paren-
chymatous cells; the 'intercellular' green
cells three- to four-angled, interposed be-
tween the empty cells in a single curved
row.

Sphagnace^. Leaves composed of a
single stratum of empty prosenchymatous
cells, with intercellular green cells interposed
between all the empty cells. Cladocarpous,
branches fasciculate.

6. Leaves without ' intercellular ' cells,
a. Leaves not papillose.
\. Loosely areolated.

ruNARioiDE.^:. Areolation of the leaf
parenchymatous, lax, containing much chlo-
rophyll.

DiscELiACE.E. Areolation of the leaves
rhomboid-prosenchymatous, destitute of
chlorophyll, empty, fusce.scent.

BuxBAUMiACE^. Areolation of the leaf
hexagonal ov polygonal, very minute, dark-
coloured, destitute of chlorophyll.

2. Densely areolated.

Mniotde^. Areolation of the leaf in
parallelograms at the base, round-hexago-
nally parenchvmatous towards the apex ;
very full of chlorophyll, or more frequently
thickened (very rarely papillose).

Bryace^. Areolation of the leaf prosen-
chymatous, ordinarily rhomboidal, abound-
ing with chlorophyll.

DiCBANACEiE. Cells of the leaf prosen-

chymatous, very often intermixed with
parenchymatous cells (rarely scabrously pa-
pillose), alar basilar cells ordinarily crowded
and ventricose, or flat and much more
loosely reticulated than the upper cells.

LEPjOTEiCHACEiE. Cells of the leaf
rhombic at the base, rectangular or both
mixed further up, smooth, without proper
alar cells.

b. Leaves papillose.

Bartramioide,^. Cells of the leaves
parenchymatous, square, ordinarily nodu-
lose or scabrous with papillse at the trans-
versal sides, never opaque.

PoTTioiDE.E. Cells of the leaves paren-
chymatous, square, ordinarily covered on
all sides with papillte above the base, but
smooth and pellucid at the ba?e.

DiPHYSCiACE.E. Leaves of two kinds;
the cauline with the cells densely hexa-
gonally parenchymatous, abounding with
chlorophyll, the pericha3tial leaves with the
cells destitute of chlorophyll and more
loosely reticulated.

PLEUROGARPI.

Distichophylla. Leaves arranged in
tivo opposite rotes.

Phyllogoniace^.

Tristichophylla. Leaves arranged in
three rotes, appearing like three, erect,
of two forms.

Hypopterygiace^e. Cells of the leaf
everywhere prosenchymatous, equal.

Polystichophylla. Leaves arranged in
four or more rotes.

Mniadelphace^. Cells of the leaf
parenchymatous, Mnioid.

Hypnoide^. Cells of the leaf prosen-
chymatous, rhombic or rounded.

BiBL. Hooker, Taylor, and Wilson, Bryol.

Brit. ; Bruch and Schimper, Bryol. Eur. ;

Schimper, Cor. Bryol. JExr. 18o5; Flora,

1856, (381 ; Hedwig, Theoria generat. ; Bri-

del, Bryol. Universa ; Miiller, Syn. Mvsc.

frond.; Dillenius, His. 3/?/5c. ;" Lanzius-

Beninga, Nova Acta, xxii. 555 ; llofmeister,

Vcrgl: Unters. 1837 ; Ber. Siichs. Gesell

Wiss. 1854 ; Flora, 1855, 4.-14; Valentine,

Linn. Tr. xviii. 409; HicliS, Linn. Tr. xxiii.

18G2, 5G7; Braithwaite, if/o"s«f>s; Stevenson,

Myc. Scot. 1879 ; Tripp, Br. Mosses, Jigs, of

spec. ; Hervey, Amertcan Sea-mosses, iSSl ;

MOTH, CLOTHES.

[ 517 ]

MOUTH.

Sachs, Bot. 359; Janczewsky, Bot. Zeit.
187i>.

MO'JII, CLOTHES. See Tinea.

MOTHEK CELL, or Parent cell, the
term coimiu)nly applied to the cell in the
interior of which a new generation of cells
is developed.

MOTHER-OF-PEARL. See Shell.

MOUGEO'TL\.— A genus of Zyguema-
eejB (Confervoid Algae), distinguished by
the conjugation of the filaments taking place
without the formation of transverse pro-
cesses, the conjugating filaments being ge-
niculately bent. There is stih obscurity as
to the mode of reprodnction of the plants of
this genus. According to Vaucher, a spore
is formed iu one of the conjugating cells,
without transfer of contents, and this, ger-
minating in situ, breaks out from the pa-
rent cell. Hassali says the plants are re-
produced by zoospores ; this has been con-
firmed by "Kiitzing, who, together with
Itzigsohn", has observed the formation of
small rounded resting-spores iu the joints,
Avhich underwent segmentation and deve-
loped a number of smaller cells, the ultimate
fate of which was not observed. All this
tends to prove that the reproduction agrees
with that of Spirociyra, where we have : —
1. large conjugation-spores, sometimes ger-
minating hi situ, producing iu some cases
new filaments, in others zoospores ; 2. zoo-
spores produced immediately from the con-
tents; and 3. what appeared to be encysted
forms of these (see Spirogyea).

M. genufexa, Ag. (fig. 139, p. 205). The
cells are about 1-72U" in diameter in
large specimens {M. major, Hass.), and
about three or four times as long ; iu smaller
specimens (J/, gemijiexa, Hass., M. (/racilis,
Kiitz.) the diameter is about 1-200", the
le.igth of the cells five or six times as great.

In fig. 139 the lowest filament does not
belong to the genus; but the method of
conjugation of Mougeoiia is seen iu the one
above.

AI. l(svis, Archer, is an Irish form.

BiBL. \^aucher, Conf. creau douce, 79,
pi. 8; HassaU, Alg. 171, pi. 40; Kutz. Sj).
Alg. 43; Tah. Fhyc. v. pis. 1-3 and 36;
Itzigsohn, ^oi!. Zeit. xi. 081, 1853; Rabenh.
Ah/, iii. 255 ; Archer, Qu. Mic. Jn. 1867.

MOULDS and MILDEWS. — These
names are generally applied indifferently to
a multitude of Hyphomycetous,_ Phycomy-
cetous and Coniomycetous Fungi ; but some
of the more common ones are especially
distinguished. Thus ordinary ' blue mould '

of cheese, &c. is Aspergillus glaucus;
another still more common blue or green
nioidd is Penicillium glaucum ; various
species of Oidium and Erysiphe are known
as the mildews of the Hop, Vine, Rose,
&c. The mildew of wheat is Puccinia.
graminis.

MOUNTING. See Preservation.

MOUSE, HAIR OF (PI. 1. fig. 3 ; PI. 29.
figs. 27, 28). See Hair of Animals and
Test-objects.

MOUTH. — The mucous membrane of
the mouth, which becomes continuous with
the skin at the lips, is furnished with very
numerous conical or filamentous papiUse
resembling those of the skin, sometimes
simple, at others branched, and a number
of mucous glands.

Its epithelium is of the pavement kind,
consisting of several layers of delicate cells ;
these are roundish in the deeper, flattened
and polygonal in the superficial layers.

Fig. 492.

Epithelial cells of the mucous membrane of the human
mouth : o, large, 6, smaller cells ; c, one with two nuclei.

Magnified 350 diameters.

The glands, distinguished, according to
their situation, as the labial, the buccal, and
the palatal glands, are rounded, about 1-36

MOUTH.

[ 518 ]

MUCEDINES.

to 1-6" in size, and open by short excretory
ducts into the mouth. They consist of
glandular lobules enveloped in areolar tissue
with elastic fibres, the whole being sur-
rounded by a firmer portion or capsule, and
a branched duct. The lobules are composed
of a number of convoluted canals or lobular

Fig. 493.

k« )

>^

Human racemose mucous gland from the floor of the
cavity, of the mouth, a, areolar coat; 6, excretory duct ;
c, glandular cseca ; d, lobular ducts.

Magnified 50 diameters.

ducts, with simple or compound caeca or
glandular vesicles, each consisting of a

Fig. 494.
a

The ducts of the lobules have a coat of
connective tissue, with networks of fine
elastic fibres, and a single layer of cylindrical
epithelial cells.

Fig. 49

o.

Diagram of two lobular duets of a mucous gland, a, common duct ;
6, lobular branch ; c, glandular vesicles in situ ; d, the same separated,
and the ducts unfolded.

Magnified 100 diameters.

basement membrane and a single layer of
angular epitheHal cells. The latter separate
very readily ; and then the caeca appear filled
with a granular mass.

Two glandular vesicles of a human racemose mucous
gland, a, basement-membrane; b, epithelium, side
view ; c, the same in surface view.

Magnified 100 diameters.

The mucous liquid of the mouth con-
tains, in addition to detached epithelial
cells, very transparent corpuscles, about
1-2000 to 1-1500" in diameter, consisting
of a delicate cell-wall, a nucleus, with a
number of minute moving molecules. We
have figured these among the Test-Objects
(PI. 1. fig. 5). They are called mucous or
salivary corpuscles. KoUiker regards them
as a form of exudation corpuscles : and this
view is probably correct ; for they may occur
in the secretion of any mucous surface, and
have no special connexion ^^ ith the salivary
glands : we have found them in m3'riad3
in the urine.

The secretion of the mouth frequently
contains very slender filaments of a fungus
(Leptothbix), with species oi Monas and
of Vibrio.

BiBL. Kolliker, Mih. An. ii. ;
Sebastian, JRech. An. s. I. gland,
labial. ; Webb, Qu. Jn. Med. Sci.
1857; Ward, Todd's Ci/cl. An.&e. ;
Klein in St/'icker, Hist. i.

MUCEDTNES.— A family of
Hyphomycetous Fungi, forming
moulds and mildews upon living
or decaying animal or vegetable
substances, and contributing to
their decomposition, character-
ized by a flocculent mycelium
bearing erect, continuous or sep-
tate, simple or branched, tubular
pellucid filaments, terminating
in single spores or strings of spores, which
soon separate from each other, and lie
among the filaments of the mycelium.
This tribe includes a number of the most

MUCEDINES.

[ 519 ]

MUCEDINES.

interestiug of the microscopic fuugi, noted
for their destructive influence upon organic
bodies which they attacls:. The species of
Botn/tir^, Old in m, Szc. spread with won-
derful rapidity as mildews over the herba-
ceous parts of vegetables and moist vege-
table substances generally; in the former
situations their spores enter the stomata,
their mycelia ramifying among the subjacent
cells, and carrying decomposition and decay
into all the soft structures. They are most
abundantly developed in a close, damp at-
mosphere. The mycelia of other kinds, as
of Penicillium, growing in liquids con-
taining organic matter, or upon decaying
vegetable substances, produce remarkable
chemical decompositions, causing a fer-
mentation of the medium in which they
exist.
See Penicillium and Ferjlentation.

Synopsis of British and nearly allied Genera.

A. Fertile filaments (pedicels) simple or
branched, terminating in single spores or
a very short row.

* Spores simple.

Sotrytis. Pedicels erect, septate,
branched ; branches and branchlets septate ;
spores solitary, on the tips of the branch-
lets, which are either racemose, umbellate,
cymose {Pvlyactis), paniculate, verticillate
(Acrostalagmus), spicate (Haplaria) or ca-
pitate.

Peronospora. Like Boti^ytis, but the
pedicels without septa; often producing
resting-spores.

Verticillium. Pedicels erect, septate, with
whorled branches terminating in a solitary
spore or a short row of spores.

Acremonium. Pedicels shoi't, subulate,
branches from a hoiizontal filament, bearing
single smooth spores.

Zyyodesmus. Like the last, but with
echiiiulate spores.

Oidium. Pedicels simple, short, erect,
clavate, septate, bearing usually one, some-
times two more or less oval spores.

Fusidium. Pedicels very short, pulviuate.
Spores elongate, fusiform.

Menispora. Pedicels erect, septate, bear-
ing fusiform or cylindrical spores, at lirst
joined in bundles.

Sceptroviyces. Pedicels erect, geniculate,
verticillately branched ; branches short, race-
mose ; spores in grape-like bunches.

** Spores septate.

Brachydadium. Pedicels branched above,
septate, nioniliform ; branches and branchlets
forming a sporiferous capitulum ; spores
ti'ansversely septate.

TricJiothcciuin. Pedicels interwoven in
tufts, the central erect, fertile ; spores acro-
genous, didymous, free, commonly loosely
heaped together.

Cephaloihecium. Pedicels simple, con-
tinuous, bearing a terminal head of didymous
spores.

B. Erect filaments {pedicels) terminating in
strings of spores.

* Spores simple.

Penicillitim. Pedicels erect, septate, peni-
cillatelj^ branched above ; branches and
branchlets septate; strings of spores attached
to the tips of the branches.

Sporotrichum. Pedicels erect, simple or
slightly branched, septate and articulate,
articulations remote, inflated ; spores simple,
usually found collected in heaps among the
filaments.

Briarea. Pedicels erect, septate, with
terminal moniliform chains of spores,
crowded into a head.

Gonatorrhodon. Pedicels erect, septate,
with chains of spores in a terminal head
and in whorls at the joints.

** Spores septate.

JDendrypMum. Pedicels erect, septate,
unbranched ; strings of spores attached in a
bunch to the apex ; spores septate.

Dactylium. Pedicels erect, septate,
branched above ; strings of septate spores
attached singly or in pairs to the apices of
the branches.

C. Fertile filaments {pedicels) inflated at
the tips or at various points in their
length, with projecting points or warts
on the inflations, bearing

* Simple spores.

Aspergillus. Pedicels continuous, erect,
simple filaments, inflated into a little head
at the summit, bearing moniliform chains of
spores, crowded into a capitulum.

Bhinotrichum. Pedicels erect, septate,
sometimes sparingly branched, the apices
clavate, cellular, bearing scattered points
supporting simple spores.

MUCOR.

[ 620 ]

MUCOR.

Tiqndaspora. Pedicels, short lateral
branches from a creeping filament, termi-
nating in cellular heads beset with simple
spores on the areolfe.

Rhopalomyces. Pedicels erect, not septate,
terminating in cellular heads, with simple
spores on the areohe.

Stachj/lidvcm. Pedicels erect, articulated,
whorlecl-branched above ; branchlets geni-
culate and articulate ; spores subpedicellate,
accumulated in little capituhform heads
inserted at the tips of the branches.

Gonatuhotrys. Pedicels erect, septate,
■with joints swollen at intervals, the swollen
joints bearing globular heaps of spores on
short spines spirally arranged.

Acmosjmrium. Pedicels erect, septate,
branched above; branches and branchlets
forming a cyme, thickened at the apex, and
furnished with globular capitules covered
all over with points ; spores simple, attached
on the points of the capitules.

IlaplotricJmm. Pedicels erect, septate,
terminating above in a continuous, simple,
solitary, sporiferous head ; spores simple.

Actinocladium. Pedicels erect, septate,
umbellately branched at the summit; spores
simple, accumidated at the tips of the
branches.

Botryosporium, Pedicels erect, septate,
with short spine-like branchlets above, spi-
rally arranged, and ternunating in four or
five short points, which support globular
heads of spores.

** Spores septate.

Arthrobotrys. Pedicels simple, septate,
with joints swollen at intervals, the swollen
joints clothed with spines bearing didymous
spores, which are collected into globular
heaps.

Some of the species are mere conditions
of perfect Fungi, as Hypoaylon and Chiviceps.

In several genera, sexual union like that
in Tuber and Peziza takes place.

MU 'COR, Micheli. — A genus of Mucorini
(Phycomycetous Fungi), forming a common
mould on paste, decaying fruits, or other
vegetable matters. I'lie general character
is that of an interwoven mass of hori-
zontal branched filaments, sending down
little root-hke ramules, and pushing up
erect, not septate, fertile filaments, which
branch at the base in a stoloniferous man-
ner, and thus form loosely grouped tufts.
At the sunnnit of the erect filaments, a
globular vesicle is formed, wliich soon be-

comes cut of!" by a septum. Its contents
become di\ided into a large number of
spores ; and the septum at the base becomes
meanwhile pushed up or protruded into the
centre of the vesicle so as to form a kind of
" core," called the coJumeUa. After a time
the vesicle {peridiole) bursts and discharges

Fig. 496.

Fig. 497.

Mueor Mu^edo.
{Ascophora foim.)
Fig. 496. Nat. size, growing on a leaf.
Fig. 4^7. Single fertile filaments, with the columella
collapsed, and fallen like a cap over the end. Magn. 50
diams.

its spores ; the pressure of the turgid colu-
mella apparently hastens the bursting. The
dehiscence takes place either by a circular
slit just above the base of the columella,
leaving this alone, surrounded by a narrow
ragged collar (Mucor), or the peridiole
bursts above and disappears by solution,
and the columella collapses upon "the pedicel
(Ascop/iorci, fig. 497). The membrane of
the peiidiole of M. 31ucedo, and perhaps of
other species, is clothed with minute spines.
The erect filament is sometimes simple,
sometimes branched. It has been conjec-
tured, though on what grounds is imcert'ain,
that the columella mav become converted
into a second peridiole, Iby being shut off by
a septum which is converted into a new
columella.

It has been imagined that Achlya is
only an aquatic form of Mucor; and this
seems not iruprobable ; however, the expe-

MUCOR.

[ 621 ]

MUCORINI.

riments we liave made on this point have
hitherto given uepitivo results.

The species of 3/hco/- described by authors
m-e prettv numerous; but we think consider-
able allowance for variation should always
be made in this genus. Rhizopus, Ehr. =
Mucor when distinctly stolouiferous. It
seems very doubtful whether Hydrophora
should be separated from Mucor. Conju-
gation takes place in one or two species.

* Fertile filaments simple.

M. Mucedo, L. (tigs. 496, 497). Myce-
lium byssoid, peridiole and spores globose,
at first white, ultimately blackish. (This
includes Ascophora Mucedo, Tode.) Ex-
tremely common. Sowerbv, Funfp', pi. 378.
fig. 6 ; Greville (Ascophora) ,Cri/pt. Fl. pi. 2G9.

M. caninus, Pers. Mycelium byssoid,
peridiole globose, ultimately yellow or fer-
ruginous ; spores globose or elliptic. Very
common on excrement of dogs and cats in
wet weather. Grev. Sc. Crypt. Fl. pi. 305.

31. fusiger, Lk. Mycelium byssoid. Peri-
diole globose, ultimately black ; spores spin-
dle-shaped. On decaying fungi.

M. clavatus, Lk. Mycelium byssoid. Cla-
vate apices of the fertile filaments simply
penetrating the globose peridiole ; spores
globose, at first white, then browni, at
length black. On rotten pears ; possibly
only a state of M. Mucedo or the following.

M. amethysteus. Mycelium thick, white,
closely interwoven. Peridiole at first white,
then pale yellow, then crystalline and pure
violet, finally violet-black or brownish ;
spores globose, filled with globose spori-
dioles (?). Fertile filament 1-40" high.
On rotten pears with the foregoing.

M. delicatuhis, Berk. Mycelium form-
ing a thin velvety stratum. Very minute ;
fertile filaments short ; peridioles globose, pale
yellow ; spores globose. On rotting gourds.

M. succosus, Berk. Mycelium forming
small, pulvinate, yellow, spongy masses.
Peridiole very minute, globose, yellow, at
length olive ; columella minute. On dead
shoots of Aucuba. Berk. Ann. N. H. vi.
pi. 12. fig. 15.

** Fertile Jilamenis branched.

M. ramosus, BuU. Mycelium Avoolly.
Fertile filaments racemose. Peridioles glo-
bose, yellow, then bluish-grey or reddish-
brown. On rotting fungi. Builiard, pi. 480.
fig. 3.

M. suhtihssi7nus, Berk. Mycelium creep-
ing, filaments exceedingly slender. Fertile

filaments branched, the short patent branches
each terminating in a globose peridiole ;
spores obhng, elliptical. A mildew of
onions. Berk. Jlort. Jn. iii. 97. figs. 1-5.

BiBL. Berk. Br. Flora, ii. pt. 2. 332;
Ann. N. H. vi. 433 ; Kort. Jn. iii. 91 ; Fries,
Summa Vec). 487 ; Syst. Myc. iii. 318 ; Fre-
senius, Beitr. z. Mycologie, heft i. 4, 18-50 ;
V. Tieghem, Ann. 6'c. N. 1875, i. 5 : Brefeld,
Flora, 1873.

MUCORI'NL— A family of microscopic
Pkycomycetous Fungi, constituting the
moulds, &c. common on most decaying
vegetable and animal substances, consisting
of a filamentous mycelium, forming flocks
and clouds in or on decaying matters, bear-
ing vesicles, on erect pedicels or sessile,
filled with minute sporules, discharged by
the rupture of the vesicles {peridioles).
These plants correspond among the theca-
sporous Fungi to the Mucedines among the
acrosporous or free-spored orders. The
peridiole consists of the terminal cell of an
erect filament, enlarged like the head on a
pin, into a globular vesicle. At first the
cavity of this vesicle communicates with
that of the pedicel ; but a septum is soon
formed ; in some genera this septum is flat,
in others projecting into the interior of the
peridiole like the "punt" of a bottle, form-
ing a hemispherical or cylindrical columella.
While this columella rises in the peridiole,
the latter becomes filled with spores, form-
ing thus a polysporous sporauge ; and it
bursts to let them escape.

The manner of bursting of the sporange
and the form of the central column vaiy
much, and afford generic characters. Thel-
actis presents a remarkable pecidiarity : each
filament terminates in a sporange containing
a great number of spores, while at its base
it gives origin to whorls of branches, the
terminal cells of which remain sterile.

Syzygites^ exhibits conjugation of its
branches, like that of the Zygnemacefe.

Some observations of De Bary tend to
show that the genus Furotium only j-epre-
sents certain conditions of Aspergillus. In
some cases the lower threads are enor-
mously developed, Avhere, from excessive
moisture, the fruit cannot be produced.
Two different forms of fruit occasionally
occur in the same thread, as in Ascophora
elegans.

Synopsis of British Genei-a.

Phycomyces. Peridiole pear-shaped, se-
parated from the apex of the erect pedicel

MUCOUS CORPUSCLES. [ 522 ]

MUSCA.

by au even joint; opening by an umbilicus.
Spores oblong, very lai'ge. Filaments caes-
pitose, tubular, continuous, and shining.

Hydropliora. Peridiole subgiobose, mem-
branous, dehiscent, at first crystalline, aque-
ous, then turbid, and at length indurated,
persistent. Columella absent; spores simple,
conglobated.

Mucor. Peridiole subgiobose, separating
like a cap (leaving an annular fragment
attached) from the erect, simple, continu-
ous pedicel, or bursting irregularly ; colu-
mella cj^linch'ical or ovate, spores simple.

(?) Acrostalacpnics. Peridioles globose,
with a columella, at the points of doubly
verticillate branches from an erect pedi-
cd.

Pilobolus. Peridiole globular, separating
like a cap from the short stalk composed of
a single cell, attached on a unicellular rami-
fied mycelium ; columella conical ; spores
very numerous, free in the peridiole.

Syzygites. Filaments erect, simple, very
much branched above, branches and branch-
lets di- or trichotomous, fertile branches
forcipate, bearing pairs of opposite internal
clavate branches, which subsequently coa-
lesce.

MUCOUS CORPUSCLES. See Mouth.

MUCOUS MEMBRANES.— Those in-
ternal canals and cavities of the body which
open externally, as the alimentary canal,
bladder, &c., are bounded by what may be
regarded as internal prolongations of the
skin, called mucous membranes.

They consist of four layers : — 1, an inner-
most or epithelial layer, corresponding to
the cutaneous epidermis ; 2, a subjacent
structureless basement membrane, which is
not always separable and demonstrable or
present ; 3, a layer of variable thickness,
consisting of connective and elastic tissue,
well supplied with blood-vessels and nerves,
often containing numerous small glands,
frequently furnished with conical or filiform
processes tei'med papillse or villi, and some-
times traversed by muscular fibres. These
three layers form the proper mucous mem-
brane ; and are supported by, 4, an outer-
most submucous laj^er or coat, composed of
the same elements as the last, but much
more lax in structure, and frequently con-
taining fatty tissue.

The mucous membranes are usually very
vascular; and injected preparations of them
are very beautiful, and to some extent cha-
racteristic.

The size and form of the epithelial cells

are to a certain extent also characteristic,
especially those of the uppermost layer ;
and a knowledge of the peculiar structure
in individual cases is of use in determining
the source of morbid mucous products mixed
with epithelial cells.

See the special articles.

MUCRONEL'LA, l\mc\B, = Lepralia pt.
Zoary incrusting ; cells with a rounded or
semicircular orifice, and an anterior tooth.
Several species ; on rocks, shells, and sea-
weeds. (Hincks, Polyz. 360.)

MUCUS. — Natural mucus contains no
essential morphological elements. As ordi-
narily met with, it often, however, exhibits
some epithelial cells, mucous corpuscles,
and numerous granules ; and the peculiar
mucous matter has a striated or fibi-ous
appearance, mostly produced artificially.
The abnormal elements are principally those
of inflammation.

BiBL. See Chemirthy, Animal.

MUD. — The organisms found in mud are
very numerous ; they consist principally of
Diatomacese and other minute Algae. The
surface of mud is often covered with yel-
lowish or greenish layers, composed almost
entirely of these organisms. The most
beautiful and most numerous forms of Uia-
tomacefB are found in the mud of sea- water,
or that of tidal rivers. On exposing a bottle
of mud and water to the light, they will
rise to the surface of the mud, some adher-
ing to the side of the bottle next the light,
and can then be "easily separated. The sur-
face of freshwater-mud frequently appears
of a blood-red colour, from the presence of
Tuhifex rivuloruin.

MUREXTDE. See Ammonia, ptjrpu-

RATE OP.

MURIATE OF AMMONIA. See Am-
monia, HVDROCItLORATE OF.

MU'RIFORM. — The term applied to
flattened six-sided cells placed one above
the other in one or more rows, like bricks
in a wall.

MU'SA, Tournef. — A genus of Musacese
(Monocotyledonous Flowering Plants), com-
prising the Bananas and Plantains. The
libro-vascular bundles of Musa aft'ord ex-
amples of spiral vessels with numerous
spiral fibres (see Spiral Structures).
Mvsa textilis affords the fibre called Manilla
hemp (see PI. 28. fig. 7). See Fibrous
Structures.

MUS'CA, Linn. — A genus of Dipterous
Insects, of the family Muscidse.

Among the well-known species, all of

MUSCACE^.

[ 523 ]

MUSCLE.

wliich have been foimed into new genera,
we may mention :

Miisca domestica, L., common house-fly.
Third joint of antennie thrice the length of
the second ; style plumose, eyes reddish
brown, front of head white, the rest black ;
thorax blackish grey witli four longitudinal
black bands, abdomen blackish bi'own above,
with blackish elongated spots, pale yellow-
ish brown beneath.

M. carnaria, L. (Sarcophac/a, Meigen),
the flesh-fly. Antennae feathery ; head
golden-yellow in front, eyes reddish : thorax
grey, with black longitudinal lines; abdomen
black, with four square white spots on each
segment ; all the body strewed with black
hairs. Viviparous, 1-2" long.

M. C(ssar, L. (Lucilia, Donov.). No
spots, abdomen green, with a metallic lustre.

jM. vomitoria, L. (Callip/ioi-a, Donov.),
bluebottle or blow-fly. Head yeUowish,
golden or white, eyes brown ; thorax black ;
abdomen shining blue with black stripes
and long black hairs.

The larvae are known as gentles. The
ova or larvae are deposited upon animal or
vegetable substances, mostly in a state of
decay, upon which they live.

Several parts of the species of Musca are
of general microscopic interest, — as the

f)roboscis (PI. 3.3. fig. 29) with its two fleshy
obes (c), kept expanded by a beautiful and
elastic framework of modified tracheae; ; the
setae or lancets (b), which are modified
maxilla}, sometimes rudimentary, with theii*
palpi (a) at the base ; the remarkable an-
tennae (PI. 33. fig. 20) ; the elegant tarsus
(PL 34. tig. 7 a), with its terminal spine,
pulvilli (figs. 7, 8 & 9) and claws ; and the
rudimentary wings or halteres (Insects,
p. 432).

Musca pumilionis {Chlorops, Meig.) de-
posits its eggs in the j'oung wheat-grain,
which is consumed and destroyed by the
larvae.

Many other members of allied femilies of
Diptera, commonly known also as flies, are
of microscopic interest, on account of their
oral setas or lancet-hke organs.

BiBL. Westwood, Infr.; Macquart, Ins.
Dipt. ; Meigen, Syst. ziceifli'ig. Insect. ; Keller,
Stuhenjliege ; Sufiblk, Mn. Mic. Jn. i. 331 ;
Lowne, on the Bloiv-Jly.

MUSCA'CE^. See Mosses.

MUSCARDINE. — A disease in silk-
worms, in wliich the whole of the sebaceous
matter is exhausted, and the blood greatly
altered, by a species of mould, Botrytis

bassiana, which is perhaps too near Botrytis
dijfusa, Grev. A few of the spores placed
on the back of a liealthy silkworm are
sufficient to impregnate the whole body.
It takes its name from the resemblance of
the diseased caterpillar to a pecuhar kind
of pastile.

BiBL. Balsamo, Gaz. de Milan, 1835;
Bibl. If. xxix. 183o; Robin, Veg. Par. 5G0;
Guerin, Seric. 1849, 1850, 1851.

MUSCLE. — Muscular tissue forms the
greater portion of the flesh of animals.

It occurs in two principal forms ; one of
which is termed organic, unstriated, or
unstriped muscle ; the other, voluntary,
striated, or striped muscle.

Unstriated muscle. — This consists of more
or less elongated, somewhat spindle-shaped,
narrow fibres (p. 74, fig. 35), having the
import of cells, and hence often called fibre-
cells ; they are, however, solid. Each con-
tains an elongated nucleus, brought to ligh?
by acetic acid, and exhibiting a reticulai;
appearance. The fibres are of variably
length (from about 1-580 to 1-2-50"), and
1-5000 to 1-3500" in diameter. They ofte,
appear longitudinally fibrous within ; and
the cell -wall is transversely wrinkledv
They sometimes exist singly in the midst
of connective tissue ; at others they are
united into rounded or flattened bundles,
and surrounded by an imperfect kind of
sarcolemma, composed of connective tissue
with elastic fibres.

Eig. 498.

Unstriated muscular fibres from the CB=iophagus of a
pig, after treatment with dilute nitric acid.
Magnified 10 diameters.

They occur most abundantly in the hol-
low viscera, as the stomach, the intestines
the bladder, and the uterus ; but they also
exist in other situations, as the spleen.

MUSCLE.

[ 524 ]

MUSCLE.

trachea and bronclii, tlie dartos, the arteries,
veins, and lymphatics, the prostate gland,
fallopian tubes, urethra, villi of the small
intestines, the skin, iris, and beneath the
lung-pleura. See.

Striated muscle. — Tlie structure of striated
is more complex than that of unstriated
muscular tissue. It consists of a number
of very slender fibres, called fibrillfe, con-
nected into bundles, termed primitive bun-
dles or fasciculi, each of which is enclosed
in a sheath or sarcolemma. The primitive
bundles are again united into secondary and
tertiary bundles, the whole being bound
together by a mass of connective and elastic
tissue surrounding each of them, and form-
ing the perimysium. This arrangement is
best seen in a transverse section (fig. 499).

Fig. 499.

TranBTerse section of a portion of the sterno-cleido-
mastoideus: c, outer perimysium; b, inner perimy-
Bium ; c, primitive and secondary muscular bundles.

Magnified 50 diameters.

v

i:

Transverse section of the muscular fibres or primitive
bundles of the human gastrocnemius : a, sarcoh'mma
and interstitial connective tissue ; b, section of flbrillse
and intermediate substance.

Magnified 350 diameters.

The primitive bundles are from about
1-1000 te 1-200" in diameter, and of a
rounded or polygonal form (fig. .500). Their
surfaces are marked by a number of trans-
verse strife, which forms the most charac-
teristic appearance of the tissue. They also
exhibit irregular longitudinal stria?, which
are the indications of the component fibrillae
(PL 22. tig. 35).

Fig. 501.

Portion of a primitive bundle treated with acetic
acid: a, sarcolemma; b, single nucleus; c, twin nuclei
surrounded by granules of fat.

Magnified 450 diameters.

The sheath or sarcolemma, when separated
from the muscular substance b}' treatment
with water, acetic acid, and alkalies, in
which it is insoluble, forius a structureless,
transparent and smooth membrane. It is
perhaps most easily seen in the muscle of
tishes by simple dissection (PI. 50. fig. 18).
On its inner side are numerous spindle-
shaped or lenticular nuclei (fig. 501).

The ultimate or primitive fibrillge in man
are about 1-20,000" in diameter, and each
exhibits numerous regidarly alternating
light and dark portions (PL '22. fig. 3G b);
the i-elative po.sitions of the two may, how-
ever, be made to change by altering the
focus ; but the dark bands are more highly
refractive than the white. The ends of the
fibrillae are distinguishable in transverse
sections of the primitive biuidles; and their
lateral margins are perfectly straight.

Difierent views have been taken of the
structure of the fibrillar, and, in fact, of the
general structure of muscle. Thus the ulti-
mate fibrilloe have been described as monili-
form or beaded (PL 22. fig. 36 c) ; this ap-
pearance, however, arises fi-om an optical
illusion, connected either with imperfection
in the object-glasses used, viewing the
object in too much liquid, or the use of too
low an object-glass, and too high an eye-
piece.

MUSCLE.

[ 625 ]

MUSCLE.

Fig. 502.

It often happens, especially when niusele
has been kept in spirit, that it separates trans-
versely iutt) a number of llat disks (fig. 502) ;
hence' it has been viewed as cousistiug of
these disks. Again, as
under certain conditions
it separates longitudi-
nally into fibrill;u and
transversely into disks,
it has been supposed to
consist of primitive par-
ticles or ' sarcous ele-
ments ' united end to
end as well as laterally.
We admit the existence
of the primitive fibrilliB
as origmal components
of muscle, though there
can be little doubt that
the fibrillfe are not ho-
mogeneous, and of uni-
form constitution either
chemical or physical.
On carefully examining
them at different foci,
it is seen that those por- ^ . .^. ,

,. i? • 1 i J CI •! ^, a primitive bundle,

tions of isolated fabriis magnified 350 diame-
which appear dark when ters, jiartly separated

the margins of the fibrils into disks, side view. B,

Y ^ • n the same, rather more

are best in focus, are magnifled, end view.

more highly refractive
than the intermediate portions, as showm
by the gi-eater luminosity they acquire on
altering the focus of the object-glass; and
that this focal effect does not arise from a
lenticular form of the parts is evident from
the straight condition of the margins of the
fibrils. Hence these more highly refractive
parts probably constitute the proper mus-
cular substance, connected in the direction
of their length by a different kind of sub-
stance, which becomes brittle under the
action of spirit, whilst the former does not ;
for the line of separation into the disks
occurs through the less highly refractive
portions. And that these compound fibrils
naturally exist, is shown by their being dis-
tinguishable in a primitive bundle without
the use of reagents, or even of mechanical
means.

It has always been supposed that the ulti-
mate fibrils are composed of cells arranged
end to end ; and the appearance represented
in PI. 22. fig. 36 a, w^iich is sometimes met
with, might countenance this notion. But
whenever it is seen, there is imperfect defi-
nition, from the presence of too much liquid,
or some other cause ; for we have never

observed it when the object was properly
arranged and examined.

On examining the fibrilla? under a very
high power, each white band is seen to be
divided by a faint dark line, Krause's line or
membrane, which is regarded as a trans-
verse partition, the compartments being
occupied by the true muscular substance ;
and it is through this line, that the fibrils
separate into the disks (PI. 22. fig. 30 d) ; or,
often the same part appears bounded at each
end by a transverse dark line (fig. 36 b), or
both parts are traversed mesially by a ti'ans-
verse dark line. In some instances we have
noticed a very delicate constriction, which
woidd account for these appearances ; but
the explanation of this we have failed to
discover.

The dark portions of the various fibriUaa
of the primitive bundles being opposite to
each other, gives rise to the coarser dark
striae seen under a low power. But it often
happens that by pressure or manipulation
this natural relation is destroyed, the direc-
tion of the strise is altered, and sometimes
those of one bundle are made to alternate
with those of the next. Hence arises an
appearance of transverse or spiral fibres
(PI. 22. fig. 35) ; but none such really exist
in muscle.

Muscle consists chemically of a proteine
compound called syntonine, resembling
fibrine in many of its properties. By pressing
muscles a liquid is obtained, containing some
peculiar organic substances.

The unstriated and the striated muscular
fibres have the same chemical composition.

In regard to the development of muscle,
it appears that muscular fibre proceeds from
cells which elongate, each becoming fusi-
form, and at the same time increasing enor-
mously in thickness; the nucleus also in-
creases, and the cell-contents become striated
to form the muscle.

The muscles are very vascular. The
smaller branches of the vessels mostly run
parallel to the primitive bimdles in the
perimysium, and anastomose by transverse
or oblique branches.

The bundles of transversely striated mus-
cular fibres in many of the lower animal.^,
and in the heart of man, are found to branch
and form networks. This may be well
observed in the muscles of the tongue of
the frog.

Schjifer points out that the dark bands of
the muscular fibrils of certain insects, as
Dytiscus maryinalis, are traversed by nume-

MUSCLE.

[ 626 ]

MUSCLE.

rous very slender parallel longitudinal mus-
cle-rods (Pl._22. fig. 36 e). These extend at
either end into the adjacent white bands,
terminating in knotted ends; forming a row,
running transversely across each white
hand.

When muscular fibres are examined by
polarized light, the sarcous elements are
seen to be anisotropous or doubly refractive,
while the intermediate substance is iso-
tropous.

They are also well supplied with nerves ;
these mostly (always, Beale) terminate in a
plexus of looped branches (fig. 503).

Fig. 603.

\MmMM:m

:-A

Termination of the branches of a nerve in a portion
of the omohyoideus muscle, treated with caustic soda :
a, meshes of the terminal x'lexus ; 6, loops ; c, muscular
fibres.

Magnified 350 diameters.

In the Lisects and Reptiles the nerves
terminate in granular nucleated swellings,
spread over the muscular bundles; their
sheaths becoming continuous with the sar-
colemma, the nerve-fibres branching off in
various directions.

Muscle undergoes important changes in
disease. Wounds are filled up with connec-
tive or tendinous tissue. In atrophy and
fatty dcg(Mieration, the bundles become
smaller, Mjfter, more readily broken up, the
transverse striae and fibrillpe indistinct, or

apparently absent, and contain yellowish or
brown pigment-granules, with more or less
numerous globules of fat (PI. 38. fig. 14 a),
and sometimes a large number of nuclei or
small cells.

Muscular fibres with ner-ve-ends from IJacerta viridit,
A. Seen in profile: P P, the terminal nerve expansion
or plate ; SS, its support or base, consisting of a granu-
lar mass with nuclei. B. The same, seen in a perfectly
fresh muscular fibre.

The interfascicular connective tissue is also
sometimes increased in amount, and fatty
tissues developed in it ; or the muscular sub-
stance is partially absorbed, and the sarco-
lemma contracting gives the bundles a
moniliform appearance (PL 38. fig. 14 6).
In tetanus, the fibres become varicose and
often ruptured, and the strife closer.

The muscular tissue of the lower Verte-
brata and some of the Invertebrata agrees
essentially in structure with that of man ;
but the sarcolemma is often much thicker,
the fibrillse larger, and the nuclei contained
within the substance of the bundles, and
sometimes arranged in regular linear series.
The margins of the bundles are also some-
times uneven, and rounded at regular inter-
vals (PI. 22. fig. 36), giving the appearance
of their being surrounded by fibres.

In many of the lower members of the In-
vertebrata, although the substance of the
body is voluntarily contractile, no trace of
fibres or bundles can be detected.

The so-called muscle-corpuscles are placed
in the interior of the fibre in the muscles
of the heart ; and they are to be met with in
Amphibia, Fishes, and Birds in the same
position.

MUSHROOMS.

[ 527 ]

MYKIANGIUM.

To obtain the separate fibrillae of striated
muscle, the tissue should be ujacorated for
about two hours in alcohol. This removes
fatty matt*^r, and renders the fibrillaj more
easily separable by dissection with mounted
needles. The fibrillfe are very minute;
hence a very small portion of the tissue only
should be taken for examination. That of
fishes, the cod or the slvate, or of reptiles,
the ii-og-, is the best for tlie purpose. Or,
the bottom of a glass vessel is covered with
chlorate of potash, slightly moistened with
wat^r, and four parts of nitric acid added.
The whole is shaken, and a portion of muscle
buried beneath the crystals with a glass rod.
In half an hour, the muscle is removed and
placed in water, and strongly shaken, when
it separates into the fibrillae (Kiihne).

The unstriated muscular fibres are best
seen in muscle which has been treated with
dilute nitric or muriatic acid (1 part acid to
4 water). This renders them more opaque,
and often cmiously tortuous or spiral(fig.498).

BiBL. Bowman, Todd's Ci/cl. art. Muscle,
and Phil. Tr. 1840-41 ; Lebert, Ann. Sc. Nat.
3 ser. xiii. ; lu-ause, Arch. An. u. Phys. h. v.
646, 1868; Moxon, Qu. Mic. Jn. 1866, 2-35;
Doyere, Ann. Sci. Nat. ser. 2. 1840 ; Kuhne,
Brucke, Arnold, and Strieker, Strieker'' s Hist.
vol. i. 1870; Quain's^w. ; Brucke, Bau d.
Muskel, Wiener Denkschr. xv. 79; Heppner,
Schultze's Archiv,Y. 1869; Schafer, P/»7. Tr.
V. 163, 429, 1873 ; Beale, Hoto ^-c. 1880 ;
'Nasse,Qi/erffestr.Musk. 1882;FYej,Hist.S0l.

MUSHROOMS. See Agaricus.

MUSSEL. — The species of Mollusca
commonly known as mussels are of interest
to the microscopist, on account of their ali-
mentai'v canal containing Diatomacete ; the
same applies also to other marine and fresh-
water Mollusca, as well as other animals
living upon these minute Algse.

If it be required to obtain the valves only,
the entire animal may be dissolved in hot
nitric acid, and the residue washed as usual
in preparing the Diatomaceae.

The gills of the common marine mussel,
Mrjtilus edulis, are well adapted for the
examination of the cilia and ciliary motion.

Mussels also frequently contain the nurses
and larvae ( Cercarice) of Dhtoma and other
Trematoda,

One of the Acarina, Hydrachna concharum,
is found in the pnllial cavity or beneath the
outer lamella of the branchial plates of the
Naiadeae (Unio, Sec).

BiBL. Dickie, Ann. N. H. 1848, i. 322 ;
Vo?t, Ann. Sc. Nat. 3 .ser. xii.

MUSTARD.— The best mustard consi.'^ts
of the ground seeds of Sinapis niyra (Cruci-
ferae) ; but those of iS". alba are largely em-
ployed. The structure of these grains is very
different from those of the substances most
commonly employed for adulteration, — for
example, wheat-fiour, which is known by
its starch-granules. Inferior samples con-
tain variable quantities of the husk of the
seed, which may be detected by the micro-
scope. Mustard is generally coloured arti-
ficially, especially when adulterated with
white meals, by means of Turmeric, the
peculiar colour-cells of which are readily
recognizable. See PI. 2. fig. 11 ; and Hassall,
Food and Adulteration, 123.

MYCE'LIUM.— The vegetative part of
the Fungi as distinguished from the fruit.
Many fungi in a barren state have been
described as genera, Himantia, Ozonium,
Xylostroma. Mushroom-spawn is simply
the mycelioid state of Ayaricus campestris.
The mycelium sometimes penetrates deeply
into wood, rendering it of various colours,
as green by Peziza ceruyinosa, red by Corti-
cium sanyuinenm, yellow by Hypoxylon
luteum.

BiBL. Berk. Outl. 39 : Crypt. Bot. 262.

MYCETOZO'A. See Myxomycetes.

MYCOIDEA.— A genus of doubtful afli-
nity, allied to Chroolepus; propagated by
zoospores, also by sexual imion, like Pythimn
and some other Saprolegnife. 1 sp. ; on the
leaves of Camellia, in India {Linn. Tr. 2nd a.
i. 301, figs.).

MYCOP'ORUM, Plot. — A genus of
Lichenaceous Lichens. 3 sp., rare (Leighton,
Lich. Flo. 437).

MYELOPLAX'ES. See Bone, p. 111.

MY'LIT'TA, Fr. — A genus apparently of
Tuberacei (Ascomycetous Fungi).

Mylitta australis, the native bread of the
Australians, has not been found with perfect
fruit ; but the structure is apparently that
of Tuberacei. The other species are doubtful,
and perhaps mere root-tubercules.

BiBL. Cd. Ic. ; Berk. Ann. N. H. 18.39, 326.

MYOBIA, Hevd. See Acarus, p. 5.

MY^OCOP'TES, Clap.— A genus of Aca-
rina. M. muscidinus, on the body of the
mouse (Claparede, Zeit. iriss. Zool. 18 ;
Murrav, Fc. Ent. 325: Megniu, 156).

MYO'MATA and MYXO'MATA. See
TrjiORS.

MYRIAN'GIUM, Mont, and Berk.— A
genus of Myriangiacei (Lichens). 31. Du-
ruri on ash and elm, rare. (Leighton,
Lich. Fl. 37).

MYRIAPODA.

[ 528 ]

MYRIONEMA.

MYRIAP'ODA.— A class of Ai-thropoda.

Char. Wiugs none ; one pair of antennae ;
legs numerous ; thorax not separated from
the abdomen.

These animals are commonly known as
centipedes, millipedes, or hundred-legs.

Body usually long, cylindrical or flattened,
and consisting of numerous rings, joints, or
somites. Head distinct, and the jointed
legs, with a single claw, arranged on each
side of the body throughout its length. A
few of them are broad, short, and flattened,

Fig. 504.

lulus terrestris. Magnified 4 diameters.

somewhat resembling wood-lice. Behind
the antennse are laterally placed the eyes,
which in some are absent; they usually
consist of a group of ocelli.

The structure of the trophi varies in the
different genera. The labruui is small, and
usually consolidated with the cephalic plate.
The mandibles (PI. 35. figs. 25, 26 6) are
often large and powerful, somewhat resem-
bling those of the spiders, and, like them,
traversed by a canal, through which the
duct of a poison-gland passes. The maxillae
are smaller, softer, and furnished with two
palpi. The labium (PI. So. fig. 20 a) is
often deeply cleft, its anterior and inner
margin elegantly toothed ; and to it are
attached tiie labial palpi (tig. 26 c). In
some the labial palpi and mandibles are
absent, the labium forming a kind of sheath
or suctorial rostrum.

The internal structm-e resembles that of
the larvae of insects.

The sexes are separate. The embryo, on
escaping from the ovum, has but few legs,
sometimes three pairs, at others none, the
number being augmented each time the
skin is cast ; the same applies to the ocelli.

The Myriapoda live in dark places, be-
neath the bark of trees, under dead leaves,
stones, &c.

They form verj' interesting objects when
properly prepared and moimted. The small
ones, when slightly compressed between
two glasses, dried in that position, subse-
quently macerated in oil of turpentine, and
mounted in balsam, become very transpa-
rent, and show the structure beautifully ;
the nervous ganglia and cords are often very
distinctly seen in these specimens without
dissection. The abdomen of the longer

specimens shoidd be slit up with fine scis-
sors, and the viscera removed — the iuteo-u-
ment being gently compressed, and driecf as
above.

BiBL. Newport, Linn. Tr. xix. ; id. Phil.
Tr. 1841 ; Gervais, Ann. d. Sc. Nat. 2 ser.
vii. ; Leach, Linn. Tr. xi. ; Jones, Todd's
Ci/cl. An. iii. ; Fabre, Ann. d. Sc. Nat.
1855, iii. ; Packard, Amer. Natural, iv. ;
Cope, Tr. Amer. Ent. Soc. 1870 ; Lubbock,
Linn. Tr. 1867; Nicholson, Zool. 310 ; Pas-
coe, Zool. 90 ; Latzel, Mi/r. 1880.

MYRIONE'MA, Grev.— A genus of My-
rionemacete (Fucoid Algse), consisting of
minute epiphytic plants, forming patches of
short, erect, simple, jointed filaments, spring-
ing from a thin expanded layer of decum-
bent cohering filaments. They are described
as bearing oblong " spores ; " but these are
probably sporanyes producing zoospores, and
it is probable that they are accompanied by
septate sporanges, as in Elachistea.

M. strangulans. Patches convex, con-
fluent ; erect filaments clavate ; spores ou
the decumbent filaments; forms brown dots
upon Ulva, or little rings round Entero-
morphae.

M. Ledancherii. Circular; erect fila-
ments cylindrical, spores ou the decumbent
filaments ; in patches 1-12 to 1-4" in dia-
meter ; on decaying fronds of Bhodymenia
and Ulva.

M. punctiforme. Patches globose; fila-
ments tapering to the base ; spores very
narrow, fixed near the bases of the erect
filaments ; on Ceramia and Chi/locladia.

M. clavatum; obscure.

BiBL. Harvey, Mar. Akj. 51 ; Grev. Sc.
Crypt. Fl. pi. 300; Harv. Phyc. Br. pi. 41 A ;
Hook. ^r.i^/. ii. pt. 1. 391."

MYRIONEMACEiE.

[ 629 ]

MYXOMYCETES.

MYRIOXEMA'OE.E.— A family of Fu-
coide;^. Olive-coloured sea-weeds, with a
tuber-shaped or crustaceous spreading froiitl,
sometimes minute and parasitical. _ Ovoid
uiiiloculiU", and iilamentous multilocular
sporanges attached to the superficial tila-
ments, and concealed among them.

Leathesia. Frond tuber-shapad.

Ralfsia. Frond crustaceous.

EU'whlstea. Frond parasitical, consisting
of a tubercular base bearing pencilled erect
filaments.

Miirionema. Frond parasitical, forming
a flat base, bearing cushion tufts of decum-
bent fllaments.

MY^RIOTHE'LA, Sars.— A genus of
Hydroid Zoophytes.

^Char. Polj-pes soUtary, cylindrical, ter-
minating in a conical pro*boscis, springing
from an adherent chitinous base; tentacles
small, capitate, covering the greater portion
of the body ; gonophoves clustering round
the base of the polypes, and containing
fixed sporosacs. M. Phryriia, on stones.

BiBL. Sars, Zool. Seise in Lofoten ; Gosse,
Mar. Zool. 19 ; Hincks, Ht/d. Zooph. 75.

MY'RIOTRICH'IA, Harv.— A ^enus of
Ectocarpaceas (Fucoid Algae), consisting of
minute epiphytic plants, forming tufts of
capillary filaments on larger Algfe. Fila-
ments simple jointed tubes, set all over with
minute, simple, spore-hke ramules, which
again are clothed with very slender, long,
jointed filaments. Fructification composed
of oval unilocular sjwranges on the sides of
the main axis, producing zoospores ; pro-
bably also multilocular sporanges exist.

M. daviformis. Main filament with quad-
rifarious ramules, increasing in length up-
wards ; fronds 1-2" long, forming tufts on
Chorda lomeniaria.

M.jiliformis. Main filaments very long,
often flexuous, set at irregular intervals
with oblong clusters of minute papilliform
ramules; 1" or more long; on Chorda lo-
nientaria and Aspei-ococais echinatus.

BiBL. Harv. PJiyc. Br.; Mar. Aly. 0-3;
Hook. Jn. Bot. i. 300.

MY^ROTHE'CIUM, Tode.— A genus of
Stilbacei (Hyphomycetous Fungi).

M. roridum, Tode, occurs on decayed
plants, fungi, &c. It has no peridium, but
consists of minute subcylindrical spores
seated on a thin base, the whole forming a
subgelatinous mass, wliich is exactly analo-
gous to the fructifying mass of Phalloidei.

BiBL. Berk. Br. FL ii. pt. 2. .323 ; Fries,
Stim. Veg. 448 ; Cooke, Handb. 559.

MYXAS'TllUM, Ilaeckel.— A genus of
Monera.

Char. A simple shapeless protoplasm
body without vacuoles, which protrudes
simple or ramifying and anastomosing pro-
cesses. Reproduction by radial fission. The
encapsuled resting body divides into a groat
number of germs, whose longitudinal axis
is radially directed towards the centre of
the globular cyst. Each separate germ sur-
rounds itself with a siliceous covering. The
germs issuing from these spore-coverings
at once assume the form of the full-grown
organism.

M. radians, Lanzerote, Canaries.

BiBL. Haeckel, Monog. of Monera {Qii,.
Mic. Jn. ix. n. s. p. 342).

MYXODIC'TYUM, Haeckel.— A genus
of Monera. Simple protoplasm bodies with-
out vacuoles ; pseudopodia ramifying, ana-
stomosing, and forming a net. Reproduc-
tion probably by division, each individual
producing new colonies. M, sociale. Bay
of Algesiras.

BiBL. Haeckel, Monera ( Qu. Mic. Jn. ix.
n. s. 339).

M YXOQAS'TRES = Myxomycetes.

M YXOM YCE 'TES.— A family of minute
Fungi, of cm'ious and interesting structure,
characterized by their development from a
mucilaginous filamentous matrix, out of
which arise sac-like dehiscent sporangia or
peridia, emitting a very remarkable, often
reticulated, filamentous structure, bearing
the spores.

The Myxomycetes grow upon bark of
trees, decayed wood, or on leaves (especially
imder certain atmospheric conditions), or on
the ground ; and their evanescent mycelium
consists of diflluent mucilaginous proto-
plasmic filaments of varied form and colom'.
In proportion as these acquire consistence,
there is formed a crust common to the
whole mass, divided within into chambers,
or a number of individuals appear separate
from it and associated on a common thal-
lus. In the first case a single peridium is
formed, which may be regarded as a com-
mon peridium if we consider the inner cells
as partial peridia soldered together, while
in the second case each individual has its
own peridium. This peridium, sessile or
stalked, is composed of one or more mem-
branous, papery, or crustaceous coats; in
some cases where there are two coats, tho
outer is crustaceous and persistent, or it is
extremely thin and membranous, and breaks
up into deciduous scales. In the outer waU

2 m

MYXOMYCETES.

[ 530 ]

MYXOMYCETES.

of some peridia, calcareous crj-stalloids are
found. Tlie mode of dehiscence varies.
fSonietimes an irregular opening is formed
at tlie summit, as iu Physarum ; sometimes
tlie peridium opens like a little box, as in
Craterium (tig. 145, p. 213) ; sometimes the
upper half falls oiF, leaving a cup-shaped
base, as in Arcyria ; or the membrane may
be very delicate, and break up entirely into
little scales, which fall oiF and leave the
capxlUtium with its spores naked, as in Ste-
monitis. The capillitium or sporiferous
structiu-e is formed of filaments, simple or
branched, free and loose, or anastomosing
so as to form a network (fig. 147, p. 214);
iu Trichia these have spiral markings, and
resemble the elaters of Hepaticne (PI. 40.
fig. 39). The filaments are often elastic,
and when the peridium bursts they rise
from the bottom of it, forming a coloured,
erect or drooping plume (Arcyria). In
many species there is a stalk, columeUa or
styJidium, in the centre of the capillitium.
The spores appear to be produced upon
these filaments by grooving out from them
in the manner of basidiospores. They are
formed in vast numbers, and lie, when com-
plete, on the branches and in the interstices
of the capillitium.

In germination, each spore liberates its
entire protoplasm, which exhibits amoeboid
movements, and protrudes pseudopodia,
which anastomose as in Gromia. In some
instances, these amoeboid bodies acquire
cilia, resembling Monads. They then con-
jugate, finally forming a sporangium, in
which the capillitium with its very nume-
rous spores are produced. Some authors
regard these organisms as animal, but this
opinion seems to rest upon partiiJ views.

Synopsis of British Genera,

* Teichiacei. Primary mucilage con-
joining several distinct peridia. Filaments
of tlie capillitium free, entwined, elastic, or
almost absent.

Licea. Peridium subpersistent, mem-
branous, bmsting irregularly. Spores in
heaps, with scarcely any filaments.

Pericha'tia. Peridium persistent, mem-
branous, bursting by a circumscissile slit.
Fila iients few, free.

Trichia. Peridium simple, persistent,
bursting irregularly at the summit. Eila-
ments densely interwoven, elastic.

Arcyria. Peridium simple, membranous,
splitting all round at the base, the upper

part very fugacious. Filaments densely in-
terwoven, elastic.

** Stemomtf-i. Primary mucilage con-
necting several distinct ]jeridia. Filaments
conjoined into a network, adnate or innate.

Cribraria. Peridium simple, membra-
nous, the upper part falling olf. FUamenta
adherent in the interior, at length exjiand-
ing into a free network above.

Dictydium. Peridium simple, subglo-
bose ; very delicately membranous, bursting
indeterminately, leaving the filaments (in-
nate) forming a cage-like latticed capUli-
tium.

Stemonitis. Peridium simple, globose or
cylindi-ical, delicately membranous, finally
evanescent. Filaments forming a determi-
nate capillitium, attached to a bristle-hke
central columella, and forming a network
around it.

Diachfcu. Peridium simple, ovate-oblong,
membranous, detached in fragments, leaving'
a radiately reticulate capillitium, with a
floccose gi'umous pulverident axis.

Enerthoiema. Peridium simple, globose,
membranous, at length evanescent, laying
bare a conical columella with a cup at
the summit, bearing beneath ascending en-
twined filanients.

*** Physabei. Primary mucilage spread-
ing widely, passing into many peridia. Fila-
ments adnate, strnight, vague. Spores black.

Craterium. Peridium simple, varied,
papery, persistent, closed b}* a Hd, which
finally falls ofi". Capillitium somewhat
chambered, foi-mcd of crowded filaments,
at length erect.

Physarum. Peridium simple, variable,
naked, membranous, bm-sting irregularly.
Capillitium floccose; filaments at first joined
into a net or forked.

Didymiiim. Peridium double ; the outer
bark-like, breaking up into little furfura-
ceous scales or mealy down, the irmer mem-
branous, bursting irregularly; filaments
vague, adnate to the peridium.

Uidcrma. Peridium double ; outer crust-
like, distinct, brittle, dehiscent, the inner
very delicately membranous, evanescent ;
filaments vague, adnate to the base.

**** ^TH ALINE I. Primaiy mucilage
producing one peridium.

Spumaria. Peridium indeterminate,
crustaceous, divided into cells by regidar
ascending folds, and finally falling awa3\
No inlernal filanients.

Aifh(dium. Peridium indeterminate, fra-

gile, falling

away,

covered with a floccose

MYXORMIA.

[ 531 ]

NAIDINA.

bark externally, ct'lltilar internall}^ by means
of filaments conjoined into membranous
layers.

Reticidana. Peridium indeterminate,
simple, nalced, fugacious, bursting iiregu-
laily, laying- bare branched, reticulated ad-
nate filaments.

Li/cogala. Peridium detemiinate, com-
posed of a double membrane, membranous,
somewhat warty, persistent, bursting at tlie
summit. Fihimeiits adnate on all sides of
the peridium.

BiBL. Schmitz, Lhtn-cpa, xvi. 188 ; De
Bary, Die Mt/cefozoa, 18G4; Plofmeister,
P/ii/s. Bot. ii. 2\)o ; Cienkowsky, Jahr. trhs.
Hot. iii. 325, 400 ; Kent, InK'klO ; Sachs,
Bot. 26o ; Cooke, Myxomyc. 1877.

MYXOR'MIA, Berk, and Br.— A genus
of Coniomycetes, containing one species, M.
atroL-iridis, forming minute cu}>like be dies,
on dead leaves of grass. It is allied to
Excipida, but differs in its concatenate spores
being connected by a slender thread, which
frequently breaks off with them ; spores
very gelatinous.

BiBL. Berk, and Br., Ann. N. H. 2 ser.
V. 457 ; Cooke, Hamlb. 459.

MYXOT'RICHUM, Kze.— A. genus_ of
Dematiei (H\^homycetous Fungi), growing
on rotten wood, paper, &c. Three British
species : M. ccesitim, Fr. ; 31. chartarum,
Kze. ; and M. dejlexum, Berk. They form
little tufts or downy balls, sending off
radiatius: branched filaments. The spores
are described as occm-riug collected in
masses about the base of the threads.

BiBL. Berk. Br. Fl. ii. pt. 2. 335 ; Ann.
N. H. i. 2G0, pi. 8. fig. 9 ; Fries, Sum. Vey.
502 ; Syst. Mye. iii. 348 ; Church, Ann.
N. H. 1862.

MY'ZUS,Passerini. — Agenusof Aphidfe.
Four species ; on the cheiTy-tree, peach
and nectarine, red-currant and gooseberry.
(Buckton, Ajihides, i. 173.)

N.

NACCA'RIA,Endl.— A genus of Ciypto-
nemiacese (Plorideous Algae), containing one
rare British species, N. Wiijghii (Pi. 4.
fig. 18), usually thrown up from deep water.
Its rose-coloiu-ed frond is 6 to 12" high, and
consists of a branched filiform expansion,
the central axis being about as thick as a
crow-quill, the branchlets quadrifarif)usly
alternate and clothed with ranmles about
1-12" lung. The cells of the main axis and
branches of the frond are large and empty
in the centre, small and closely packed at

[ the circumference ; the raniulea are com-
posed of jointed dichotomous filaments
having a whorled arrangement, surrounded
bj' gelatinous matter. The .spores arebi)rne
on branches of the filaments of the ra-
mules, the fertile ramules being swollen in
the middle.

BiBL. ll^Y\ey,Mar. Alg. 152, pi. 201);
Ph/c. Br. pi. 38; Greville, Ahj. Br. pi. IG.
NAIDI'NA.— A family of Setigera (An-
nulata).

Char. Worm-like, annulate or segmented,
without suckers or soft leg-like appendages ;
segments furnished with partially retractile
bristles or seta3, excepting the first three or
four ; head distinct from the body.

Freshwater animals, living among aquatic
plants, or burrowing iu mud. Sexes distinct;
propagation by ova and spontaneous trans-
verse division. The bristles are moved by
muscles, and answer the purpose of legs ;
they are situated on the upper or under
surface of the body, mostly in rows.

The Naidina are remarkable for the sin-
gular process of non-sexual multiplication
which they present before attaining sexu d
maturity. A bud is thrown out between
two rings near the middle of the boJy, and
is developed into a fresh individual ; more-
over the parent body separates at this point,
and becomes two individuals ; and prior to
the detachment of the bud, others are
formed from the same segment.

Nais, Miill. Four anterior segments
without upper bristles.

N. Scotica. Cylindrical, ends obtuse, the
anterior smooth and cylindrical, the portion
behind it with a double row of thin tufts of
prickles, shorter than the diameter of the
body; mouth and anus terminal; no pro-
boscis; length 1".

N. serpentina. Cylindrical ; head snake-
like, with a produced lower lip ; eyes two ;
upper bristles subulate, lower forked or
hooked; length about Ih," ■ The lower
bristles with a globular swelling below the
middle ; segments SO-OO ; head with 4 dark
transverse band?.

N. prohoscidca. Cylindrical, flattened iu
front ; first four segments divided by a
stricture from the body, the first or head
being prolonged into 'a filiform proboscis ;
two eyes; upper bristles simple, lower
forked ; length 1-2"; on the roots of aquatic
plants.

Cliatogaster, Baer. All the segraents
without upper bristles.

C. vennicidaris. Truncate in froi.t ; no

2 H 2

NAILS.

[ 582 ]

NAILS.

eyes; mouth terminal; setaa bifid; length
1" ; among- Lemna, in ditches, and in the
respiratory chamber of the Lymnjeida}.

See TuBiFKX.

BiBL, Schmidt, Miiller's ArcJiiv, 1846,
406; Duges, Ann. Sc. Nat. 2 ser. xv. 319;
Johnston, Cat. non-;)arasit. Worms ; Doyere,
3Ie?)i. Linn. Soc. Norniandti, x. ; Claparede,
Rcch. 1861.

NAILS. — These organs, which consist of

modified epidermic formations, are imbedded
posteiiorly and laterally in depressions, or
are covtn-ed at these parts by a fold of the
skin. The posterior depression (fig. 505 J)
is much deeper than the lateival depressions
(fig. 506 c).

The nail itself consists of the root (fig,
505 1), the body (k), and the free end (/«).
The root extends over that part of the
matrix furnished with the ridges, and is

Fi?. 505.

e

/

.//-

Longitudinal section through the middle of the nail and its matrix, a, matrix and cutis of the back and point
of the finger; 6, rete muco^um of the point of the finger; c, that of the nail ; d, tliat of the bottom of the root-
fold ; e, the same of the back of the finger ; f, epidermis of the point of the finger ; g, its origin beneath the margin
of the nail ; h, eindermis of the back of the finger; i, its termination at the upper surface of the root of the nail;
Ic, body, I, root, m, free end of the proper nail.

Magnified 8 diameters.

either entirely lodged in the posterior de-
pression of the cutis, or the crescentic por-
tion of it is exposed. The body of the nail
is imcovered except at the sides, which are
overlapped by the lateral folds oi the skin.

The portion of the cutis (fig. 506 a) to
which the under sm'face of the nail, except
that of the anterior free portion, is attached
— the matrix or bed — is covered with ridges
(fig. 506 a) extending from the posterior
part or root of the nail to the convex mar-
gin of the white crescentic portion called
the lunale, where they become larger and
higher, forming plates which run to the end
of the matrix. The margins of the ridges
and plates are covered with short papillfe.
The anterior portion of the matrix of the
nail is very vascular.

Tlie under surface of the root and body
of the nail is covered with depressions and
ridges to adapt itself to those of the matrix.

Two layers are distinguishable in the
nails — an under soft layer (figs. 505 r/, 506 r,
507 B), corresponding to and directly con-
tinuous with the rete mucosum of tlie skin,
and the upper horny layer forming the true
nail (figs. 506/, 505 k, 507 C). The lower
surface of the latter is furnished witli small

ridges (fig. 507 o), which occupy con'espond-
ing furrows in the mucous layer.

In minute structure the soft layer resem-
bles that of the cutaneous rete, except in
the deeper layer of cells being elongated
and arranged perpendicularly (fig. 507 h).

The horny portion, or proper nail, con-
sists of epidermic cells, flattened and aggre-
gated into plates or lamiufB (fig. 507 C).
In the natural state, these cells are undistin-
guishable, except at the root and the under
surface, where the nail is in contact with
the mucous layer — the remainder merely
exhibiting shorter or longer dark lines, re-
presenting the flattened nuclei, or indicating
the existence of the laminae. But if a
section of nail be treated with solution of
caustic potash or soda, the nucleated cells
swell up, and resume their proper form and
appearance.

Tlie blood-vessels of the bed of the nail
form a coarse plexus in the coriuni of the
matrix, from which loops are given off to
the papillit! ; and the proper bed of the nail
has a mucli finer plexus and loops ascending
to the ridges.

Numerous moduUatcd nerve-fibres lie in
the subcutaneous tissue of the nail-bed, and

NAI1>S.

[ 51)3 ]

NASSULA.

TraiisTorse section of tlie nail and its n.atnx a, matrix- witli its rirlges (Mack); 6, cutis of the lateral folfl : c.
r.te n.ucosiun oi tlu- .-ame; </, rete mucosum of the nail with its ridges (white) ; e, enidermic layer of cutaicous
told;/, proper .ub.tance of the nail, with short teeth on its under suifaee. <-. ipiatimic lajerol uitaiicous

Magnified 8 diameters.

lose their medullary sheath at the level of
the corium, and theu run vertically to the
surface.

Fig. 607,

5*. e

a

Transverse section of the body of the nail. A, cutis
of the matrix. B, rete mucosum of the nail.. C, epi-
dermis of the same, or proper nail, a, plates of the
rnatrix ; 6. i>lates of the rete mucosum of the nail ; c,
ridges of the proper substance of the nail ; d, deeper
perpendicular cells of the rete mucosum of the nail ;
e, upper flattened cells of the same ; /, nuclei of the
ceUs of the proper nail.

Magnified 250 diameters.

The cutaneous epidermis (fig. 506 e) ex-
tends for a certain distance into the lateral
and posterior depressions of the skin, covers
the anterior portion of the root, the poste-
rior part of the body, and the lateral mar-
gins of the nails, terminating in a fine layer
which, however, is nowhere directly con-
tinuous with the substance of the nail.

Laminae of a nail after boiling with solution of caustic
soda or potash. A, side view. H, surface view, a, cell-
membranes ; 6, nuclei seen from above ; e, the same in
side view.

Magnified .350 diameters.

BiBL. KoUiker, Mik. An. ii. and the Bill.
therein ; Biesiadecki, Striclxer''s Hist.

NAIS, Miill. See NAioiNA.

NANNOPUS, Brady,— A genus of Cope-
podous Entomostraca. (Brady, Cn^). ii.)

NAR'COTINE. See Alkaloids, p. 31 .

NAS'SULA, Ehr.— A genus of Holo-
trichous Infusoria, of the family Trachelina.

Char. Body covered with cilia arranged
in longitudinal rows; mouth surrounded by
a cone of rod-like teeth ; no proboscis nor
ear-like processes.

The gastric sacculi of those animals fre-
quently contain a coloured liquid, derived
from the solution of partly digested Oscilla-
torice,

N. elegans (PI, 31. fig, 45; h, teeth).
Length 1-144 to 1-120".

N. aurea (PI. 31. fig. 4G), Length 1-120".

NAUPLIUS.

[ 534 ]

NECTRIA.

It is questionable how far this genus is
diliereiit from Chilodon.

BiBL. ]<]hr. Infus. 8:;S ; Stein, Inf. 248 ;
C.ihn, Qii. M. Jn. 1859 5 Clap, et Lachm.
Etudes ; Kent, Inf. 494.

NAU'PLIUS. ' See Critstacea, p. 216.

NAVICELLyE. See Gregarina, p.36o.

NAVIC'ULA, Bory.— A genus of Diato-
mace?e.

Char. Frustules single, free; valves ob-
long, lanceolate or elliptical, (sometimes with
the ends narrowed and produced, rarely
constricted in the middle, furnished with a
longitudinal line or keel, and a nodule in
the middle and at each end; surface of
valves covered with dots arranged in trans-
verse or slightly radiating rows, producing
an appearance of lines, altliough both dots
and lines are often invisible by ordinary
illumination.

Valves usually symmetrical, and the keel
median ; but in two species the keel is
sigmoid and the valves inequilateral. Some-
times the keel is double. There is mostly
a little space between the rows of dots
(PI. 15. hg. 8), so that these readily exhibit
transverse lines or strias by unilateral oblique
light ; but sometimes they are pretty uni-
formly distributed, as in many of the species
belonging to the tirst section of Fleui-o-
sigma.

Species or forms very numerous ; Kiitzing
describes 170, some of them, however, be-
longing to IHnnuhiria, Pleuromyma, and
other genera. Ilabenhorst notices 237 spe-
cies. Many may have been derived from
a frustule of a Schizonema or CoUetoneinn
which had escaped from its gelatinous
envelope !

The formation of sporangial frustules has
been noticed by us in Navicula amphirhyn-
clms, and they are contained in a siliceous
sporangial sheath or case. The process is
sufficiently illustrated by the figures (PI. 50,
figs. 19-24): fig. 19, side view of the parent
frustule; fig. 20, front view of conjugating
frustules, with young sporangial sheath ;
fig. 21, empty mature sheath ; fig. 22,
crushed empty sheath and jmrent frustides
in situ ; fig. 23, sheath, one parent frustule
and sporangial frustule in front view ; fig.
24, sporangial frustule in side view.

N. cuspidata (PI. 15. fig. 6, side view;
fig. 7, front view ; a, hoo])). Valves lan-
ceolate, somewhat rhomboid, acuminate ;
freshwater; length 1-350 to 1-200". Valves
slightlv iridescent, no striae bv ord. ilium.

N. didynia (PI. 15, fig. t)). " Valves ellip-

tic oblong, slightlv constricted in the middle;
marine ; length 'l-(JOO to 1-300". Ends
sometimes broadly rounded, and the con-
striction very deep.

N. vhnmhoides. Valves rhomboid-lanceo-
late; colourless and not striated by ordin.
ilium.; freshwater; length 1-350". Striae
85 in 1-1000" (Sm.).

N. a)])p/iirh)/7ichns(P\. 50. fig. 19, side view ;
fig. 22, front view of conjugating frustules).
Valves linear, or nearly so, suddenly con-
tracted near the produced and obtuse ends ;
freshwater; length 1-500 to 1-250",

N. affinis. Valves elliptical, contracted
and linear towards the rounded ends ; fresh-
water.

BiBL. Smith, Br. Biat. i. 4G ; Kiitz, Ba-
cill. 91, and Sp. A/ff. 69 ; Grev., n. sp., 31ic.
Tr. 18<d6, 84 & 126; O'Meara, pec. forms,
Qu. Mic. Jn. 1872, xii. 283 ; Kabenh. Aly. i.
169.

NEBA'LIA, Leach.— A genus of Phyllo-
podous Entomostraca.

Char. Antennse two pairs, large and rami-
form ; eyes two, stalked ; legs twelve pairs,
eight branchial and four natatory ; carapace
large, enclosing head, thorax, and part of
abdomen.

N. bipes (PI. 19. fig. 28), Marine ; body
yellowish ; length 3-8".

BiBL, Baird, Br. Entom. 36 ; Clans, Sieb.
Sf Kdll. Zeits. 1872, 323 ; An. N. H. 1879,
iv, 418.

NECKE'RAj Hedwig.— A genus of Hyp-
noid Mosses.

Elegant little perennial plants, growing
on trunks of trees and shady rocks, having
stems pinnately branched, bearing compla-
nate leaves arranged in eight rows (fig. 484).

N. crispa, Dill., found in mountainous
districts, is a large moss, with stems 4 or 6"
long or more, growing horizontally from a
creeping rhizome,

NECTRIA, Fries.— A gemis of Sphfe-
riacei (Ascomycetous Fungi), distinguished
from true Sphcerice by the free, membranous,
flaccid, brightly coloured perithecium, the
pale papilla, and the gelatinous pale nucleus
expelled in the form of a drop or of white
flocks ; the asci contain eight pellucid
spores. The imperfect forms of tliese plants
are described as distinct genera. Thus
Tubercularia vidyaris, common on bark of
dying or dead trunks, and on dead twigs of
birch especially, ripens into N. cinnabarina ;
this we have observed ; and it is probable
tiiat other Conioni3Tetous forms will require
to be reduced in like manner. Nectria

NEMALEON.

[ 535 ]

NEPIIROSELlNriS.

includes the following Sphfrrm of the
liritisli Flora — cinndharina, coccinen, ochra-
cca, aurnntiit, i-osella, citrina, Pezizci, san-
yuinea, episplucrid, kc. ; and several new
species are described by Messrs. Berkeley
and Hroome.

EiUL. Fries, Smn. Vecj. 387 ; Berk. &
Broome, Ann. N. H. 2 ser. xiii. 467 ; Cooke's
HancU). 780.

NEMA'LEON, Tarji-ioni. — A genus of
Cryptonemiaie* (Florideous Algae), con-
taining two British species, one, N. muUiJi-
dum, not uncommon on shells and stones
near low-water mark. Its frond consists of
a somewhat cartilaginous, simple or once or
twice dichotomous cord, 3 to G" high and
1 to 2" in diameter, of a dull purple coloiu-.
The cord consists of a dense axis formed of
interlaced longitudinal filaments, clothed
with horizontal, dichotomously-branched
filaments, moniliform and coloured towards
the circumference of the cord. The fruit
consists oi :—favelUdia, consisting of glo-
bular masses of spores attached singly to
the filaments of the periphery, witli a tri-
chogyne (PI. 4. fig. 12 c) ; and collections
of antheridia, consisting of minute hyaline
cells seated on the peripheral filaments, but
discharging spermatozoids (PL 4. fig. 12 h).

BiBL. Harv. Mar. Alg. 153, pi. 21 B,
Phyc. Br. pi. 36 : Derbes and Solier, Ann.
Sci. Nat. 3 ser. xiv. 274, pi. 35 ; Thuret,
ihid 4 s^Tt 111. 21.

NEMAS'PORA, Fries.— A supposed ge-
nus of Melanconiei (Couiomycetous Fungi),
the species of which present two forms, one
bearing minute conidia {Nemaspora), the
other spores (Liherfella, Desmaz.), and which
probably also will be found to exhibit an
asciferoiis form. X. crocea, Pers., is common
on beech trees, N. Rosre on roses and lilacs.
They are iit first minute gelatinous masses
of conidia, coherent into a nuclt'us under
the epidermis, devoid of a perithecium ; the
spores finally exude as a gelatinous tendi'il ;
the spores are curved and of an orange-
colour. Nemaspora consists really of sper-
mogonous fruits, and Libertella of stylospo-
rous fruits of Ascomvcetous genera.

BiBL. Berk. Br. Fl. ii, pt. 2. 355 ; Fries,
Sum. Veg. 413 ; Desmaz. An7i. Sc. Nat. 1
s^r. xix. 209.

NEMATIIE'CIA.— Wart-likecollections
of vertical filaments found on the surface of
the fronds of the Cryptonemiaceje (Flo-
ride^).

NEOTTIOS'PORA, Desmaz.— A genus of
Sphferonemei(Stylosporous Fungi), remark-

able from the fusiform spores being fur-
nished with three or four terminal threads.
N. caricuni grows upon dead leaves of
sedges, bursting from beiieath the epidermis
by a circular black orifice, from which an
orange-coloured (sometimes olive-coloured)
gelatinous mass of spores escapes in the
form of a cirrhus. Diameter of conceptacles
about 1-80".

BiBL. Desmazieres, Ann. Sc. Nut. 2 ser.
xix. 346; Berk. <& Broome, Ann. N. II.
2 ser. xiii. 379.

NE'PA, Linn. — A genus of Ilemipterous
Insects.

N. cinerea, the common water-scorpion,
is of a dirty brown colour, the body broad
and flat, with two long terminal respiratory
tubes ; anterior pair of legs stout and greatly
elbowed, posterior formed for crawling and
not swimming.

PI. 33. fig. 26 represents the trophi. The
labium {i) is three-jointed, with two small
lobes between the second and third joints ;
the four sette (mandibles and niaxillfe) are
furnished with teeth, directed towards the
free end (and not as shown in the figure) ;
the lingua or tongue (*) is trifid at the
apex.

The lateral tracheae are dilated opposite
the thorax to form two internal respiratory
sacs. The eo-o-s are oval, and ^^ith seven
reflexed filaments at one end.

BiBi,, Westwood, Intr. ; Dufour, Hemip-
teres.

NEPEX'THES, L.— A genus of Nepen-
thaceSB (Dicotyledonous Plants), in which
the spiral vessels have four parallel fibres
(see Spiral Structures),

NEPHROCYTIUM, Nag.— A genus of
PalmeDacese ; consisting of 4-16 minute
reniform green cells, enclosed in an ample
envelope. 2 species ; in ditches and buggy
pools. (Rab. Fl. Alg. 62; IS'ag. Einzell.
Alg. 79.)

NEPHRO'DIUM, Rich.— A genus of
Aspidieae (Polypodiaceous Ferns, fig. 224.
p. 320). A very large number of species,
cosmopolitan. "^Brit. sp. : N. Filix-mas,
Theltjpteris, Oreopteri^ {montnmmi), rit/i-
dum, cristatum, spinidosimi (dilatatuin), and
CBTnfda.

NEPHRO'LEPIS, Schott.— A genus of
Aspidiefe (Polypodiaceous Ferns). 7 spe-
cies, tropical. (Hooker, Si/n. 300.)

NEPIIR0'3IIUM, Nyl.— A genus of
Lichenaceous Lichens. Three species; rare.
(Leighton, B. Lich. Fl. 99.)

NEPIIROSEL'MIS, Stein.— A genus of

NERIUM.

[ 536 ]

NERVES.

Flagellate Infusoria. Free, solitary; fla-
gella two, arising- from the middle of the
ventral side. N. oHvitcea,Temiorm; length
1-1000" ; freshwatei-. (Kent, Inf. 405.)

NERIUM. See Stomata, and Liber
(p. 461).

NERVES and NERVOUS CENTRES.
— The nervous system is usually regarded
as consisting of two parts — the nerves, which
are divided into the cerebro-spinal and the
sympathetic; and the nervous centres, re-
presented by the brain and spinal ; cord,
with which must also be placed the ganglia.
These parts are composed essentially either
of nerve-tubes, nerve-cells, or of both these
elements.

The nei-ve-tibres may be arranged in two
groups, the meduUated and the non-medul-
lated.

The meduUated nerve-tubes are most nu-
merous in the white portion of the nervous
centres and in the nerves. They are slender,
soft, cyhndrical filaments, varving in diam-
eter from 1-20,000 to 1-1 iOO". When
quite recent, they are transparent and appa-
rently homogeneous (fig. 509, 1), but they
really consist of three distinct parts— an
enveloping membrane or sheath ; a tenacious
liquid, the white substance of Schwann ;
and a soft, elastic, and probably fibrous
axis, the axis-cylinder, or band of Remak.

The outer sheath or tubular membrane
of the nerve-tubes is a thin structureless
transparent membrane (fig. 510, 2, 3 a, 4 «),
containing nuclei. It is very visible and
thick in the nerves of the mesentery of the
frog, and in the electrical organs of the tor-
pedo. It is furnished with annular con-
strictions at regular intervals.

Within the outer sheath is a hollow
cylinder or tube (figs. 509, 5i, 510, 3b, 4 b)—
the white substance of Schwann. It is
homogeneous and tenacious in perfectly fresh
nerves, but soon after death becomes coagu-
lated, sometimes externally only, giving a
double outline to the walls of the nerve-
tubes (fig. 510, Ji, 511), or becoming granular
externally, and remaining liquid internally.
It is also easily altered by pressm-e, some-
times escaping in globides or masses of
various forms (myeline), from the ends or
the broken sides' of the tubes, at others
accumulating at intervals in various parts
of the tubes, giving them an elegant vari-
cose appearance (fig. 511). It is frequently
called the medullary sheath, and those nem-es
possessing it are meduUated.

The third structure exists within the last,

in the form of a rounded or flattened, pale,
fibrous band, occupying the axis of the tube,
and called the axis-cylinder (figs. 509, 2 b,
3 c, 4 a, 5; 510, 1 b)\ this is the essential
nervous element.

Fig. 509.

/.

5-

Nerve-fibres. 1 . From nerves of the dog and rabbit,
in tlie natural state : a, fine, b, moderate, c, large fibre.
2. From a frog, after the addition of serum : a, drop
forced out by pressure ; b, part of the axial fibre con-
tained in it. 3. From the human spinal marrow, treated
with serum ; a, sheath ; b, w hite substance with a double
outline ; c, axial fibre. 4. Fibre with double outline,
from the human fourth ventricle : n, axial fibre. 5. Two
isolated axial filires, with a portion of the white sub-
stance adherent to the right-hand one.

Magnified 350 diameters.

These three structures of nerve are some-
what difiicult of demonstration. The outer
sheath may sometimes be shown by pressing
the nerve-tube, which forces out the white
substance. Boiling the nerves in absolute
alcohol, with the subsequent addition of
caustic alkali, or in acetic acid, when crys-
tals of fat separate from the white substance
(fig. 510, 1), will answer the same purpose.
Strong nitric acid, and afterwards potash,
causes the white substance to exude; and
the axial fibre being dissolved, the yellow
sheath is left empty and very distinct. So-
lution of corrosive .^sublimate has also been

NEKVES.

[ 537 ]

NERVES.

recommended. The axial band is best seen
in nerves treated Avith strong- acetic acid, or
cold absolute alcohol, ether, chromic acid,

Fio-. olO.

Nerve-tubos. 1. From a frog, after boiling with acetic
acid and alcohol : a, sheath ; b, axial band : c, crystals
of fat. 2. Isolated sheath of a frog's nerve boiled with
Boda. 3. From the human fourth ventricle, after treat-
ment with soda : a, sheath ; 6, white substance exndiiig
in drops : the axial band has been removed in the pre-
paration. -1. Human, treated with soda : a, sheath; b,
white substance ; the axial band not visible.
Magnified 350 diameters.

Fig. 511.

Human nerve-tubes, showing tubes of various sizes ;
some with a single, others with a double outline ; some
varicose, others with the white substance in a granular
state.

Magnified 350 diameters.

&c., and staining fluids. Osmic acid so-
lution hinders the coagulation uf the medul-

lary substance, which is oily and very re-
fractive, and turns it black.

Chemically, the sheath and axial band
consist of a proteine compound, and the
white substance of a mixture of cerebrine
with leeythine.

In the 7ion-meclulIated nerves the fibres
are of three kinds. The primitive nerve-
fibrils present the simplest form, and are
very fine and thread-like. They are only
visible witli powers greater than 500 linear,
and may be traced to their junction wath
ganglion-cells and thicker nerve-fibres. No
internal structure can be distinguished ; and
they become varicose here and there with
reagents, such as osmic acid, finally becom-
ing diffluent. They abound in the neigh-
bourhood of the termination of other nerves,
for instance, in the retina (see Eye).

The second kind of fibres have been called
naked axis-cylinders, and are thicker than
the primitive fibrils. They are transparent,
and more or less striated longitudinally,
being composed, like the axis-cylinders of
medullated neiTCS, of minute longitudinal
fibrils. When connected with multipolar
ganglion-ceUs, this fibrillation is often di-
stinct under the action of reagents. They
have only been traced for short distances ;
and it is evident that they and the primitive
fibrils may become covered with a sheath
and merge into the medullated type. The
thu'd kind consists of a thicker or thinner
bundle of primitive nerve-fibrils, according
to the kmd of axis-cj'linder present, imited
together by a structureless, perfectly trans-
parent, extremely thin nucleated tissue —
the tubular sheath of the medullated fibres.

In the cerebro-spinal nerves, the nerve-
tubes are aggregated into bundles, and sur-
rounded by an envelope of connective tissue,
called the neurilemma, in which blood-
vessels ramify, thus corresponding with the
arrangement of the primitive tibrillas of
muscle. Sometimes, towards the termina-
tions of the nerves, the neurilemma appears
as a homogeneous membrane with elongated
nuclei.

Branching or division of all the ner\'e-
fibres, except the non-medidlated primitive
kind, occurs occasionally in and near the
nervous centres and in the nerve-trunlis, and
frequently in the periphery. The best
example of peripheral divison is in the
electric eel, where one medullated fibre
divides millions of times to supply the sub-
cutaneous fat-like organ. l)ivision into
fibres may be seen in sections of the spinal

NERVES.

[ 538 ]

NERVES.

cord of the ox treated with carmine and
ammonia.

In the grey, sympathetic, or ganglionic
nerves, the fibres of which are sometimes
called gelatinous fibres, the nerves are paler
than those of most of tlie cerebro-spinal
nerves, and they are scattered through

From the human sympathetic. A. Portion of a grey
fibre treated with acetic acid: a, fine nerre-tiibes ; b,
nuclei of Remak's iibre8. B- Three ganglion-globules,
one with a pale process.

Magnified 350 diameters.

numerouslongitudinal non-medidlated fibi'es
(Remak's fibres), containing elongated nuclei
(fig. 512).

Net-ve-cells, nerve-corpuscles, or ganglion-
globules are masses of fibiillar protoplasm,

granular and faintly coloured ; they have a
nucleus and nucleolus. They are most nu-
merous in the cineritious or dark portions of
the nervous centres, and in the ganglia ; but
they are met with in the trunks and termi-
nal expansion of nerves, as the retina, &c.
Some are furnished with a nucleated capsule
(fig. 513, 2 a) ; this is easily seen in the
cells of the ganglia, but with difficulty in
those of the central organs.

They are rounded, elongate, pyriform, or
angular (fig. 51.3). Some are simple, others
are furnished with one, two, or more simple
or branched processes ; hence they are
described respectivelv as uui-, bi-, or midti-
polar. Their contents are a soft, tenacious,
but fibrillar mass (fig. 51-3, 3), consisting of
a clear, homogeneous, proteine basis, and a
number of larger and smaller granules, as
well as a nucleus and nucleolus. In size
they are very variable, from 1-5OU0 to 1-500".
The granules are sometimes colourless, at
others yellow, brown, or black ; and occa-
sionally these are aggregated to form a
mass.

A number of fine fibres radiating from
the nucleus and nucleolus may be seen
traversing the cell-substance, which con-
tains granular, yellow, or reddish-brown
pigment. Chloride of gold renders the
nucleus very distinct. Beale has shown
that two processes are given ofl" from the

Fig. 513.

Nerve-cells and fibres from the auditory nerve. 1. Nerve-cell with the origin of a fibre,, from the anastomosis
between the facial and auditory nerve in the meatus auditorius externus of the ox: o, ceil-membrane ; h, contents ;
c, pigment; ^.nucleus; p, prolongation of the sheath upon the nerve-tube; y, nerve-tube. 2. Two nerve-cells with
tubes from the auditory nerve of the ox: a, sheath with nuclei; 6, protoplasm, fibrillar really ; c, nucleus; rf, origin
of tube, with nucleated sheath; e, tubes, '■i. Separ.ite contents of a nerve-cell with a nucleus and two nucleoli.

Magnified 350 diameters. \

iM^RVES.

[ 539 ]

NERVES.

small end of the bell-shaped ganglion -cells
of the sympathetic in the frog, and that
whilst cue pursues a straight com'se, the

Fig. 514.

Cells from the central grey substance of the human
Bpiual marrow. Some are connective-tissue cells.
Magnified 350 diameters.

other forms a series of coils around It, both
lying within a nucleated slieath continuous
with that of the ganglion-cpll.

On'ijin of Nerve-fibres. — The ganglion-
cells, whether multipolar or unipolar, are in
continuity with nerve-fibres. Some gan-
glion-cells are merely nucleated dilatations
of the axis-cylinder ; and others, which are
also bipolar, are true ganglion-cells; for the
more or less globular cell-mass is continuous
with the axis-cylinder and with the gTanu-
lar matter of the medullary matter, but the
tubular sheath of the nerve stops short of
the cell.

Multipolar ganglion -cells are invariably
connected with one meduUated nerve-fibre,
which passes off without branching or
diminishing in calibre. Its axis-cylinder is
continuous with the fibrillar structure of the
protoplasm of the ganglion-cell, and it be-
comes invested with the medullaiy sheath
soon after leaving the cell. The other pro-
cesses either communicate with adjacent
multipolar cells, or break up after repeated
branching into a great number of processes,
which,however, are clearly continuous with
the fibrillar protoplasm of the cell, but are
uncovered by any medullary sheath. Their
idtimate termination is doubtful ; but it is
inferred that many of them become continu-
ous with the axis-cylinders of nerves. So

Large cells from the grey cortical layer of the human cerebellum. Magnified 350 diameters.

fibrillar are the processes under reagents,
and so fibrous is the appearance of the gan-
glion cell-mass, deficient as it is of cell-wall.

that it is imagined that the fibrous structure
of the axis-cylinders is continuous with that
of each other through the cell-substance.

NERVE3.

[ 540 ]

NERVES.

Doubtless many nerve -fibres originate from
very small cells imbedded in tlie grey sub-
stauce, and which are usually destroyed by
the processes of preparation.

The ganglia (fig. 516) consist of nerve-
tubes either separate or united into bundles,
intermingled vsdth nerve-cells, from which
some of the nerve-tubes arise. The tubes
and cells are imbedded in or supported by a
stroma of connective tissue, sometimes
homogeneous, at others more or less di-
stinctly fibrous, forming an apparent sheath
to the ganglia, and ending in numerous

septa, rarely but occasionally forming a di-
stinct envelope to the individual cells ; some-
times it consists of elongated, triangular, or
spindle-shaped nucleated cells — in short,
corresponding to connective tissue in various
stages of development.

The finer nerve-fibres are often with difii-
culty distinguished fi'om fibres of connective
tissue; but the frequent occiu'reuce of nuclei
will often serve to distinguish them.

The nerves are developed from the ele-.
mentary embryonic cells, which at first
appear rounded or slightly elongated and

Fig. 516.

Fig. 617.

Fig. 518.

Fie ."iie. Sixth thoracic sympathetic ganglion of the left side of a rabbit. Been from behind, after treatment with
soda r.2. trunk of sympathetic; Jt. c, conmnmicating branches, each bifurcating; .S'p^sphmehnic branch. *, gan-
glial'braneh, with large and smaU branches probably going to vessels ; 5-, ganglion-globules and ganghal hbres.

MacniCed 40 diameters. , ,. • . ,1 i_ /■ » 1 ■ n ?

he. r,17. 1. Ganglion-globules from a spinal ganglion of a four-months human io-tus: », nueleus in the pale
process of the cell? 2. Nerye-tubea in development, from a two-months human ioDtus. A. Cells from the ciueri-
tious cerebral substance of the same fcctus. ,,^^ o-xt iir 1

Fie 518 1 Two nerre-libres from the ischiatic nerve of a four-months foetus. 2. Nerve-tubes from a newly-
born rabbit: a, sheath ; h, nucleus; c, white substance. 3. Nei-ve-Ubrc from the tail of a tadpole: a, 6, c, as above;
at d the fibre has still the embryonic character.

somewhat flattened. In their further gi-owth
they either retain their primitive shape (fig.
617), or send out persistent lateral pro-
cesses, so forming nerve-cells or ganghou-

globules ; or the processes of adjacent cells
unite into nucleated fibres, much resembling
those of the sympathetic system, in which
the white substance and axial fibre of the

NEUROGLIA.

[ 541 ]

NIDULARI VCET.

nerve-tubes are formed as secondary depo-
sits (fig. 51 8).

In atrophy and degeneration of the
nervous elementss, the nerve-cells become
loaded with fat and pigment, and the walls
of the nerve-tubes thiuner, brittle, and the
white substance more or less replaced by
granules of fat.

The nerve-fibres are very difficult of ex-
amination, and require a high power. They
mav bo hardened in chromic acid or Miiller's
liquid. Chloride of gold with tlie subsequent
addition of very dilute acetic acid, briugs to
light the axial fibre ; while the medullary
sheath is darlvened br osmic acid.

BiBL. KoUiker, Mik. An. 2 ; Todd, Ci/cl
iii. ; Gerlach, Mik. Stud. ; Reniak, Monatsb.
Acad. Berlin, 1853 ; Schultze, Sfnict. new.,
1868 ; Lister & Turner, Qu. Mic. Jn. 181j0,
29 ; Mayer, Strick. Hist. ; Meynert, ibid. ;
Deitevs,' Gekirn u. Mark d. Mensch., 18(35;
Clarke, Phil. Tr.lSGS; Beale, Phil. Tr.lSSO,
1862, 186-3, 1864, Croon. Lecture 1865, Qu.
Mic. Jn. n. s. vols. iv. & v., & How; Clelaud,
Qu. Mic. Jn. 1870, 126; Darwin, Qu. Mic.
Jn. 1874, 110; Schmidt, M. Mic. Jn. 1864,
200; Frej, Hist. 62i; Bevan, If. Mic. Jn.
xvi. 105.

NEUROGLIA. — A granular connective
tissue, with fine elastic fibres and cells sur-
rounding the nerve-fibres in the brain and
spinal cord.

NEUROP'TERA.— An order of Insects,
containing the Dragonflies (Libellulid^).
NEW-ZEALAND FLAX. See Phor-
MiuM and Textile substaxces.
NEWT. See Triton.
NICOTirOE, Aud. & Edw.— A genus of
Crustacea, of the order Siphouostoma, and
family Ergasilidte.

N. astaci (PI. 19. fig. 36, fem.) is found
upon the giUs of the lobster.

The sides of the body are extended into
two remarkable lobes, containing the ovaries
(rt) and the intestinal canal.

Bibb. Baird, Br. Ent. 300; Van Beneden,
Ann. Sc. Nat. S ser. xiii.

NIDULARIA'CEL— A small family of
Gasteromycetous Fungi, including the Ni-
dularmi or bird"s-nest-like Fungi, and the
Carpoboli, which contain only one concep-
tacle. They are curious aud very interest-
ing Fungi, growing on the ground among
decaying" sticks, dung, &c., bearing upon the
flocculent mycelium yellow or dull-coloured
fruits or receptacles (fig. 519). The ex-
ternal part of the receptacle consists of a
more or less globular or ovate peridium.

whicli bursts whon mature, in tlie Carpoboli
by a lid or by m )re or less regular slits, in
the Nidulariui by an orifice which enlarges

Fijr. 519.

Fig. 520.

Fig. 521.

Cyathus vernicosus.

Fig. 519. A ripe receptacle. Nat. size.
Fig. 520. The same, opened vertically.

so that the mouth becomes turned out as a
spreading lip around a cup-shaped cavity
(fig. 519). The Carpo-
boli, containing only
one conceptacle, proj ect
this with elasticity
when ripe. The Nidu-
larini contain many
conceptacles lying like
eggs in a nest (figs.
519, 520), in Ci/athus
and Crucibidum (fig.
521) attached by a funi-
culus. The structure
of the conceptacles is
alike in all. The en-
velope of each is triple
(fig. 522); and they
form a cavity lined by delicate filaments
which converge towards the centre, where

Crucibulum vulgare.

A conceptacle detached
from the receptacle.

Magnified 12 diama.

Fi»-. 522.

Cyathus vernicosus.

K nearly ripe receptacle, cut open vertically, showing
tlie two halves filled with conceijtaclea.

Magnified 3 diameters.

their extremities are expanded into basidia
cro\\aied by four spores (fig. 523), which
are cylindrical and almost sessile. The
filaments being of very unequal length, the

NIDULARIACEl.

[ 542 ]

NITOPHYLLUM.

basidia are intermingled with them in the
cavity of the conceptacle, not forming a
definitely marked layer.

Fig. 523.

Cyatlaus striatus.

Basidia and spores from the fertile layer of a
conceptacle.

Magnified 2o0 diameters.

Fig. 524.

Fig. 525.

A\, \\j I.

Cyathua striatus.

Fig. 524. Vertical section of a young receptacle. Magn.

10 diams.
Fig. 52.5. Another, more advanced. Magn. 10 diams.
Fig. 526. Another, still more advanced. Magn. 5 diams.

Synopsis of British Genera.

* Carpoholi. Peridium containing only
one conceptacle.

Atractnhuhis. Perid. simple, cup-shaped,
sessile, closed at first by an umbonate lid.
Conceptacle spindle-shaped, simple, iudehis-
cent, projected when ripe from the bottom
of a peridium.

Thelehuhis. Perid. simple, sessile, round-
ish, urceolate-inflated ; mciuth entii'e. Con-
ceptacle globose, papilliform, protruded
from the mouth.

Spltaroholus. Perid. double, eacli layer
bursting in a stidlato manner, the internal
membrane at length turned inside out, and
projecting the globular conceptacle elasti-
caUy.

** NiDULAKiNi. Peridium with many
conceptacles.

Crucibulum. Perid. at fii'st globose-capi-
tate, afterwards crucible-shaped, orifice ex-
posing numerous disk-shaped smooth concep-
tacles, each with a globular process beneath,
prolonged into a long, slender funiculus.

Cyathus. Perid. at fii'st obovate or fusi-
form, closed by a veil, then widely open
at the mouth, exposing ten to eighteen
disk-shaped thick conceptacles, umbilicate
beneath, and attached to the walls of the
peridium by a compound peduncle.

Nidularia. Perid. sessile, subglobose,
finally open without evident veil ; concep-
tacles numerous, disk-shaped, nestling in

gelatinous

mucus, without a funiculus.

BiBL. Tulasne, Ann. Sc. Nat. 3 ser. i. 41 ;
Schmitz, Linncea, xvi. 141 ; Sachs, Bat.
Zfit. xiii. 823 ; Pringsheim, Jahrb. ii. 199 ;
Eidam, CoJm. Beit. ii. 221.

NIPHOB'OLUS, Kaulf.— A genus of Po-
lypodiaceous Ferns, with elegantly articu-
lated veins and numerous naked sori at the
tips of free branchlets ; under surface with
woolly tomentum. = Poli/podium pt. (Hook.
Syn. 349).

NIR'MUS, Nitzsch. — A subgenus of Phi-
lopterus. Like Docophonis, but the trabe-
cuhe absent or rudimentary. On the black-
cock, grouse, and pigeon.

NITELLA. See Charace^.

NITOPHYL'LUM, Greville.— A genus
of Uelesseriaceas (Fiorideous Algae), con-
taining about half-a-dozen British species,
only two of which are commonly met with.
Their fronds are membranaceous, of reticu-
lated (parenchymatous) structure, mostly
rosy red, without ribs, or with irregular ribs
towards the base. The membranously ex-
panded frond of N. punctata/n (PL 4. fig. 0),
4 to 12" high, is either regularly dichoto-
mously divided or parted into two or three
principal lobes, which have a border of
dichotomous wedge-shaped lobes. N. lace-
riim lias the frond 2 to 10" high, much
dichotomously divided and marked with
flexuous veins, the segments mostly linear,
waved or fringed at the margins. Fructifi-
catidU consisting of spores, tetraspores, and
antheridia. 1. Spores sessile on the fronds,
arising from tufted filaments contained in
coccidia ; 2. tetraspores, forming distinct
scattered spots on the frond ; -3. antheridia,
minute cells standing perpendicularly on the
surface of the frt)nd, collected into patches,
only distinguishable by the help of the
microscope.

NITRATE OF POTASH. [ 6^3 ]

NOCTILUCA.

RiBL. Ilarvev, 3Iar. Alg. IIG, pi. 15 B ;
Phiic Br. ; Greville, Ahj. Br. pi. 12 ; Thuret,
Aivi. Sc. Nat. 4 »6v. iii. 22.

NITRATE OF POTASH. See Potash,
Nitrate of.

NITRIC ACID is useful as a reag-ent,
aud for separating the organic matter of the
Diatoiuace;« from the siliceous valves.

NITZSCiriA.— A genus of Annulata.

BiBL. Jolinst. Non-parasitic Worms,
1855.

NITZSCIITA, Denny (Liotheum).—A
genus of Anoplura.

N Bur)neisteri is the louse of the com-
mon swift (^Cypselus apus).

BiBL. Denny, Monogr. Anopl. 230.

NITZSCII'IA, Hass.— A genus of Dia-
tomaoefe.

C7iar. Frustules free, single, compressed,
usually elongate, straight, arched, or sig-
moid, with a longitudinal, not median, ex-
ternal keel (? ), and one or more longitudi-
nal rows of puncta ; suture in front view of
frustides not median.

The valves have no nodules; we have
not been able to satisfy ourselves of the
presence of the external keel ; upon the
portions of the valves forming the middle of
the side \dew of the frustules are one or two
longitudinal rows of slightly elongate dots
or puncta (PL 17. fig. 10 d), often visible
under ordinary illumin. ; surface of valves
covered with smaller dots, mostly opyjosite
(not quincuncial) (fig. 10 d), invisible under
ordinary illmniuation.

The frustules aud valves are either linear,
lanceolate, or of intermediate forms, some-
times constricted or beaked.

N. sigmoidea (PI. 17. fig. 9 : a, side view;
b, front A"iew) ; length 1-75" ; freshwater.

N. hniceolata (PI. 17. tig. 10: a, front
view of frustule ; b, front view of single
valve ; c, side view of frustule) ; length
1-150" ; fig. 10 d exhibits the two kinds of
markings as seen with the stops. Marine.

N. birostrata, Sm. (PI. 17. fig. 11 : a, side
view; b, front view); length 1-70"; ma-
rine.

N. acicidaris (PI. 17. fig. 13 6); length
1-.300"; freshwater.

N. reversa (PL 17. fig. 12) ; brackish
water.

N. tcenia (PL 17. fig. 13 a); length
1-250" ; brackish water.

BiBL. Smith, Br. Diat. 37 ; HassaU,
Ah/a, 4.35; Rabenh. Alg. i. 149.

NOBERT'S LINES and Plates.—
These consist of parallel bauds or groups of

parallel lines, beautifully rided upon a slide
with a diamond. The bands are of equal
breadth, and the lines in each successive
baud are more numerous aud closer than in
those of the preceding. In the 20-band
plate, R. Beck determined the distances of
the lines to be as follows, in fractions of an
inch.

Band

Band.

1.

l-13000th

11.

l-49000th

2.

l-1.5000th

12.

l-52000th

3.

1-1 8000th

13.

l-55000th

4.

l-21000th

14.

l-57000th

5.

l-23000th

15.

l-59000th

6.

1 -27000th

IG.

1-61 000th

7.

1-3 1000th

17.

l-63000th

8.

l-36000th

18.

l-6o000th

9.

l-41000th

19.

l-67000th

10.

l-45000th

20.

l-7U000th

More recently, a 30-band plate has been
produced, in which the lines are ruled to
over l-100,000th of an inch. The exhibition
of these lines requires sufiicient magnifying
power, oblique illumination, and large an-
gular aperture in the object-glass. See
Test-Objects. Also Frev, MiJcr. ; Pigott,
Mri. M. Jn. ix. 63; Robin, "Mic. 313 ; Brown,
Pr. Roy. Soc. xxiii. 531 {Mn. M. Jn. xv.
27.3) ; Rogers, 3In. M. Jn. xvi. 74 ; Webb,
ibid. xvi. 171 ; Beck, Micr. 1865, 19.

NOCTILU'CA, Suriray.— A genus of
marine Protozoa, now usually referred to
the Infusoria.

N. miliaris (PL 53. %. 23) is rounded, of
about the size of a pin's head, with a ten-
tacle-like, transversely striated, curved pro-
process, by means of which it propels itself
through the water. Near its attachment is
the mouth, on one side of which is a tooth-
like projection. The mouth leads by means
of a tubular gullet to an irregular hollow
stomach in the sarcode of the interior of the
animal ; and there is a definite anal opening.
The body consists of a radiating protoplas-
mic network. There is a nucleus; but no
vacuoles have been observed. The part to
which the tentacle is attached is plicate aud
depressed, so as to render the body some-
what bilobed ; it has no carapace.

Multiplication takes place by subdivision
and internal gemmation. Sexual union
also takes place, the animals placing their
oral apertures close to one another, a proto-
plasmic bridge being formed, which unites
the nuclei of the two indi\iduals ; the two
Noctilucse then fuse, aud the nuclei become

NODOSARIA.

[ 544 ]

NOSTOC.

one. At last a large individual represents
the two. Swarm-spores, wliicli become
tailed, ciliated, and furnished with the tooth-
process, are formed within the conjugated
Noctilucse and escape.

It is phosphorescent, rendering the sea
luminous by night ; but under the micro-
scope the luminosity does not appear to be
uniform, but dependent upon a number of
repeated flashes ; it is increased by physical
and chemical agents.

BiBL. Quatrefages, Ann. Se. Nat, 3 &6r.
xiv. ; Gosse, Nat. Ramb. ; Ivrohn, IVieg-
man'nJs Archiv, 1852; Huxley, Mici\ Jn.
1855; Brightwell, Ann. N. H. 1850, vi.
305 ; Pring, Fhil. Mag. 1849 ; Cienkowski,
Schultzes Archiv, 1871 & 1872 ; Carus, Man.
Zool. ; Webb, Qu. Mc. Jn. iii. ; Busch, Qu.
Mic. Jn. iii. ; Alhnan, Qu. Mic. Jn. 1872,
326; Kent, Inf. 397.

NOBOSA'lilA, Lamk.— A subgenus of
Hyaline J'oraminifera. Shell elongate,
straight, rounded, conical or cylindrical,
with distinct or close-set chambers, smooth,
ridged, or spiued; orifice terminal, mostly
produced and round (N. raphanus, PI. 23. fig.
29). It passes by curvature into Dentalina
&c., by eccentricity of aperture into Mar-
ginulina &c., and by compression into Liu'
gulina and Frondicularia.

Found in Carboniferous and Permian
rocks ; abundant in the Trias and Lias, and
in many strata of later date : living in many
seas in rather deep water,

BrBL. D'Orbigny, For. Foss. Vien. 38;
Williamson, Fee. For. 14 ; Morris, Cat. Br.
Foss. 37 ; Parker and Jones, A7m. N. H. 3.
iii. 478 ; Carpenter, For. 101.

NODOSARrNA, P. & J. — A genus
(strictly a type species) of Hyaline Fora-
minifera. Its chief subgroups are Nodosaria
and Cristellaria, which are one in essential
characters of structm-e and mode of growth:
Glandnlina, Lingulina, Dentalina, Rimnlinaj
Vaginulina, Margimdina, Flahellina, Fron-
dicularia, and others are subsidiary forms.
No line of division can be drawn between
tliese approximate allies; for the straight,
the curved, and the spiral lose themselves
in each other — the amount of curvature and
of spii-ality, and the greater or less closeness
of the chambers and of the whorls being
varying characters. The style of ornament,
chiefly longitudinal ribbings, passing into
spines and tubercles, is the same throughout
(see PI. 23. figs. 28 to 39).

BiBL. Parlfer and .Jones, Ann. N. II. 3.
iii. 477 ; Carpenter, Forajn. 159.

NOUOSINEL'LA, Brady.— One of the
Arenaceous Foramiiufera, being a Lituoline
isomoi-ph of Nodosaria. Fossil in the Car-
boniferous and Permian rocks. (Brady,
Monogr. Curb. For., Pal. Soc. 1876.)

NODULA'RIA =Lsmanca. — Supposed
to produce poisonous effects. (Beale, HozPf
.^•c. 281.)

N(EMATE'LIA, Fr.— A genus of Tre-
mellini (Hymenomycetous Fungi) distin-
guished by the presence of a central nucleus
distinguished from the gelatinous surround-
ing substance. N. encephala is common in
subalpine countries on larch raUs, looking
like a small brain, as the name implies.

BiBL. Fr. Ep. 591; Berk. Outl. 290;
Cooke, Handb. 350,

NOLEL'LA, Gosse. — A genus of Infun-
dibulate Ctenostcmatoua Polyzoa, of the
family Vesiculariidae.

Distinguished by the erect, subcylindrical
cells, crowded on tubes forming an unde-
fined incrustiug mat ; tentacles eighteen,
forniiug a bell. One species :

N. stipitata.

BiBL. Gosse, Mar. Zool. ii, 21.

NONIONI'NA, D'Orb.— A subgenus of
Hyaline Foraminifera, subordinate to Pohj-
stomella. Shell nantiloid, usually sym-
metrical ; many chambers, opening with a
transverse slit at the base (^N. crassula, PI.
24. fig. 18). By septal modifications it passes
into Polystomella {P. striato-2nmctata, and
P. crispa, PI. 24. figs. 19, 20).

Nonioniiia is 'not known for certain in
strata older than the Chalk and the Tertiaries.
It still abounds in shallow seas of temperate
latitudes.

BiBL. D'Orbigny, For. Foss. Vien. 109 ;
Parker & Jones, Ann. N. H. 3. v. 102 ; Car-
penter, For. 286.

NORMANDI'NA, Nyl. — A genus of
Pyrenodei (Lichenaceous Lichens).

Char. ThaUus squamose, squamulte thin,
rounded ; apothecia black, immersed. N,
Icetcvirens, green, common on damp earth.

BiBL. Leighton, Lich. F'lora, 440.

NORMANEL'LA, Brady.— A genus of
Copepodous Entomostracea. N. dubia,
North Sea. (Brady, Copep. ii. 87.)

NOSTOC, Vaucher.— The typical genus
of the Nostochacea), distinguished from the
allied genera by the definitely formed hard-
ened pellicle or rind enclosing the fronds,
which are composed of a gelatinous sub-
stance (fig. 527) in which are imbedded
numerous more or less beaded filaments
(fig. 528). The filaments are composed of

NOSTOC.

[ 545 J

NOSTOC.

rows of cells (I'l. 8. fig. 7) wliicli iucreaso I found on damp ground, wet rocks, mosses,

the length by I'epeated transverse sub-

Nostoc commune.
Natural size.

division ; here and there are larger cells
(a, c) which appear brighter than the rest,
resembling the iH^sicu/ar cells of the allied
genera. The filaments break up after a
time into short fragments, which by cell-

Fig. 528.

Nostoc caeruleum. ,
Filaments. Magnified 200 diameters.

division produce new filaments. The pelli-
cle of the frond bursts, allowing the gela-
tinous mass to escape, and the filaments to
spread abroad in the water ;
these consist of short straight-
ish pieces, which move slowly
along in the direction of their
length ; after a time they cease
to move, and a new gelatinous
envelope is formed around each
piece like a transparent sheath.
They soon become enlarged
considerably, and then divide
in the direction of the length of
the filament (fig. 520), which
becomes so disintegrated that
the filament forms a spiral,
by the increase of which
through further transverse
cell-division the mass be-
comes confused, until the de-
velopment of a greater quan- j^^S'^ms
tity. or the gelatmous matter
makes the filaments more distinct.

The Briti.^h species of this genus are

Nostoe
verrucosum.

Filaments mul-
tiplying by
8ul)division.

ifcc, and free or attached to stones, in
fresh water (PI. 8. fig. 7). They are very
numerous, and the following only can be
noticed.

* Frond globose or sifbr/lobose.

Nodoc minutissimum. Frond globose,
fronr 1-30 to 1-4'" ; filaments equal, deep
teruginous green, densely entangled ; peri-
derm growing brown.

N. lichenoides. Fronds from the size of
a mustard-seed to that of a pea, aggregated
and heaped together ; filaments equal,
loosely entangled, ajruginous or olivaceous ;
periderm pellucid, colourless, firm.

ft. ve<icariuin\ larger, soft, wit li a fuscous
distinct periderm, mucous within, some-
times hollow.

N. spji(pj-icum. Frond the size of a pea,
firm, blackish seruginous or somewhat olive-
coloured, soft within ; filaments pale green,
loosely entangled ; periderm firm, colourless
or fuscescent, subopaque. On stones in
mountain rivulets. Meneghini states that,
when dried and again moistened, it emits a
pleasant odour like violets. Hassall thir.ks
it probably an immature form of N.fuli-
aceum.

N. ccerideum. Frond from the size of a
pea to that of a sloe, soft and slimy, pale
a3ruginous blue ; filaments unequal, loosely
entwined, joints oblong-elliptical ; periderm
colourless, pellucid, soft. On mosses iu
flowing water or very moist places.

N. pruniforme. Frond the size of a large
round plum, deep seruginous green, very
soft and watery within ; filaments unequal,
bright aeruginous green, loosely entangled,
joints subdepressed, dimidiate ; periderm
leathery, crystalline ; unattached, iu fresh-
water pools or rivulets.

-** Frond foliaceous, irref/ular, or vesicular.

JV. foliaceum. Frond terrestrial, mem-
branous, erect, plaited, olive-green ; fila-
ments slender, copious. On clayey ground
constantly moistened bv oozing water.

N. comnnme (fig. 527, & PI. 8. tig. 7).
Frond terrestrial, gelatinous, subcoriaceous,
greenish, irregularly plaited ; filaments
nearly equal, tiexuous, colourless or green,
loosely entangled, the joints loosely con-
joined, distant or geminate, subspherical,
depressed, with a central opaque spot ;
periderm hyaline, srowing brown. Gravelly
soils, garden walks, rocks, barren pastures,
&c. ; very common iu autumn nnd winter.

2n

NOSTOCHACE^.

[ 546 ]

NOTODELPHYS.

N. verrucosum, Vaucher. Frond blad-
der-shaped, softh' leathery, fuscous-green ;
filaments spiral, densely entangled, joints
globose ; periderm gelatinous, soft, green
or dirty brown. On stones in streams.

N. van'effafum, Moore.

BiBL. The works above quoted ; Itzig-
sohn, JBoi. Zeit.xu.52l (1854); Sachs, Bot.
Zeit. xiii. 1 (1855) ; Thuret, Mhn. Societe
de C/ierbomy, 1857, An7i. N. 11. 3 ser. ii. 1;
Kiitzing, Sp. Alg. 295, and Phijc. gen. 204 ;
Fischer, Nostoc. 1853; Hicks, Qu. Mic. Jn.
1861, ii. 90 ; De Bary, Regensh. Fl. 1863 ;
Rabenh. Alq. ii. 161.

NOSTOOHA'CE^.— A family of Con-
fervoid AlgfB, forming gelatinous strata or
definitely shaped gelatinous balls or masses,
on damp ground or floating at the bottom
of water; consisting of minute, nnbvanched,
usually moniliform, microscopic filaments,
tranquil or oscillating, imbedded in a mass
of muciliiginous or tirmish substance (the
amorphous matrix is produced by the fusion
of the gelatinous sheaths of the individual
filaments) ; filaments finally breaking up.
Cells of the filaments of three kinds: — 1.
ordinary cells ; 2. vesicular cells or hetero-
cysts, usually large and without granular
matter, frequently with erect hairs ; 3. spo-
ra7u/ia or spot-angial cells, produced by the
enlargement of the ordinary cells, globular,
elfiptical or cylindrical. Eeproduction by
spores has been observed in Cylindrosper-
mum by Thuret, who finds that the spo-
rcmgial cells produce in their interior one
thick-coated spore, which, after a season of
rest, germinates and breaks out from the
sporange to grow into a new cellular fila-
ment.

Synopsis of British Genera.

Nostoc. Phycoma globose or spreading,
gelatinous or coriaceous, containing simple,
curved, and entangled, moniliform, colour-
less or greenish filaments, composed of cells
imbedded in a gelatinous matrix; hetero-
cysts globose, interstitial, larger than the
other joints.

Monnrmin. Frond a gelatinous, elon-
gate, curled and convolute sheath, enclosing
a single moniliform filament ; heterocysts
interstitial ; sporangia developed from joints
most distant irom the vesicular cells.

Trichormns. Heterocysts interstitial and
terminal. Sporanges at first formed from
the cells most distant fi'om the heterocysts.

Sphcerozyga. Heterocysts interstitial ;
sporanges from the nearest cells.

Cylindrosporum. Heterocysts terminal ;
sporanges like the last.

DolicJiospermiim. Heterocysts interstitial ;
sporanges of unequal length, and without
definite arrangement.

Aphanizomenon. Heterocysts none (?) ;
sporanges usually simple and of unequal
length,

Spermosira. Heterocysts interstitial,
single or in pairs ; sporanges as in Trichor-
mns.

Exotic genus : Trichodesmium.

BiBL. Ralfs, Ann. N. H. 2 ser. v. 321 ;
Klitz. Tab. Phyc. i. 91 ; Thuret, Ann. Sc.
Kat. 2 s6r. ii. ; Meneghini, Mem. Turin
Acad. ser. 2. v. 1843 ; AUman, Mic. Jn.
1855; Eabenb. Alq. ii. 161; M-Nab, Qu.
Mic. Jn. 1874, 215 ; Sachs, Bot. 251.

NOTA'MIA, Flem.— A genus of Gemel-
lariidfB, Cheilostomatous Polyzoa.

Char. Cells placed back to back, facing
opposite directions ; tobacco-pipe-shaped
bird's-heads above each pair. One species :

K. bnrsaria (PI. 36. fig. 21). An elegant
microscopic object.

BiBL. Johnston, Br. Zooph. 294; Busk,
Cat. Pohjz., Brit. 3Ins., 36; Plincks, Polyz.

koTAS'PIS, Plerm.— A genus of Ori-
batea (Acarina). Cephalothorax with
lamellar appendages, tarsi with three
homodactyle claws. N. bipilis, common in
France. (Murray, Ec. Ent. 217 ; Michael,
Jn. Mic. Soc. 1880, 177.)

NO'TEUS, Elir.— A genus of Kotatoria,
of the family Brachionsea.

Char. Eyes absent, foot forked ( = eye-
less Brachionus).

N. quadricornis (PI. 44. fig. 13). Carapace
suborbicular, depressed, scabrous, areola te,
with four spines in front and two behind ;
freshwater ; length 1-10 to 1-70".

BiBL. Ehr. Infus. 602; Pritch. Infus.
707. -^ •'

NOTH'RUS, Koch. — A genus of Ori-
batea (Acarina). Cephalothorax without
lamellar appendages, tarsi Avith three hete-
rodactyle claws. N..^mugcr, violet-brown,
covered with dirt. N. horridus, in moss.
(Murray, Ec. Ent. 219.)
^ KOfOCHL^'NA, Brown.— A genus of
Grammitidero (Polypodiaceous Ferns),
Several species; tropical. (Hook. Syii.

NO'TOCHORD.— The new name for the
Chorda dorsalis.

NOTODEL'PHYS, Allm.— A genus of
Copepodous Entomostraca.

NOTODROMAS.

[ 547 ]

NUCLEUS.

y. asa'dicola (PI. 19. fig. 22) resembles
Cyclops in general appearance. The ex-
ternal ovnry is a single organ, lying across
the back of the abdomen ; eye single ;
marine.

•3 other species.

BiBL. Allman, Ann. N. H. xx. 1 ; Baird,
Br. Enfom. 2;37 ; Bradv, Copep. i. 141.

NOTOD'ROMAS, Lilljeborg.— An Os-
tracode related to Candona, among the Ct/-
pridce. It has long set?e on the lower an-
tennae, and two eyes. Its carapace has a
flat ventral surface with limiting ridges ;
and with this portion upwards it floats at
the top of sunny pools in Europe and the
British Isles (iV." monac/ms, Miiller), and in
Australia {N.fenesfrala, King).

BiBL. BradV, Lijin. Tr. xxvi. 379.

NOTOGO'NIA, Perty.— A gemis of Eu-
chlanidota (Rotatoria).

Char. Lorica present, dilated posteriorly,
with two pointed processes on each side.
Eyes two, red; jaws curred, strong, with
two or three teeth ; caudal setae strong ;
between Confervcs.

BiBL. Perty, Lehensf. 42.

NOTOM'MATA, Eiir.— A gemis of Ro-
tatoria, of the family Hydatinaja.

Char. Free ; eye single, cervical ; tail-
lilre foot with two toes ; rotatory organ
simply ciliated.

In some the rotatory organ is extended
laterally in an ear- or arm-like form.

Ehrenberg describes twenty-three species,
some of which are parasitic, N. petromyzon
and parasita living within Volvox glohutor^
and N. Wernecldi within the vesicles of
Vaucheria ; and divides them into the sitb-
genera : — Labidodon, jaws each with a
single tooth ; Ctenodon, jaws each with
several teeth.

Kotommata granularis is the male of N.
BracMonus.

Many of the species are large and well
adapted for the study of the internal
structure.

N. centrura (PI. 44. fig. 14 ; 1-5, jaws and
teeth). Body attenuate at each end, foot
small, and hard ; cephalic auricles short ; no
lateral -setae ; freshwater; length 1-36".

BiEL. Ehr. Inf. 424; Duj. Inf. G4G ;
Pritchard, Infus.'GSl ; Hudson, M\ M. Jn.
1875.

IsOTOXEC'TA, L. — A genus of aquatic
Hemipterous insects.

The insects belonging to this genus have
the elytra membranous m the posterior part,
and the body is more or less boat-shaped.

Fig. 530.

Kotonec'ta glauoa.
Magnitied 3 diameters.

The hind legs are very long, and when
stretched out resemble and act as a pair of
oars. The Notonectm swim on their backs,
and generally in a slightly inclined position,
on the surface of ponds and ditches. They
descend with great rapidity. They are
very voracious, and live on aquatic larvae,
biting also very sharply. Their mouth-
organs and limbs aiFord interesting micro-
scopic objects.

N. glaiica (the water-boatman) is com-
mon in pools.

NOTOPTEROPH'ORUS, Costa. — A
genus of Copepodous Entomostraca. Two
species ; marine. (Bradv, Copep. i. 141.)

NUBECULA'RIA, Befrance.— An Im-
perforate Foraminifer ; shell bpaqite, often
sandy, protean, parasitic on shells and algae ;
straight, scale-hke, or cervicorn ; chambers
with imperfect base; at first spiral; aperture
oval, produced, often lipped. Fossil in the
Trias, Oolite, and Tertiaries; common in
shallow waters of warm latitudes (N.rugosa,
PI. 23. fig. 21).

BiBL. Jones & Parker, Q. J. Geol. Soc.
xvi. 456 ; Carpenter, Eor. 69.

NUCLEUS AND NUCLEOLUS of
Animals. See Cell, p. 138.

NUCLEUS and NUCLEOLUS of
Plants. — The term nucleus is applied in
botany to two very diflerent things — first
to the central body of the young ovules of
Flowering plants, and secondly to a pecu-
liar structure met with in the interior of
cells. The first will be described under the
head of Ovule ; the cell-nucleus and nu-
cleolus are treated of in the article Cell,
Vegetable.

Few parts of the minute organization of
plants are more obscure than the structure
and ftmction of nuclei : some authors re-
gard them as of the highest physiological
importance ; others consider their import

2n2

NUCLEUS.

[ 548 ]

NUCLEUS.

altogetlier unknown. The nucleus may be
observed most easily in the pareuebymatous
cells of the herbaceous structures and flowers
of Monocotyledons (PI. 46. fig. 28/>), or in
the young cells of the hairs of Flowering
plants generally (PI. 47. figs. 8, 9b), or in the
embryo-sacs of ovules (PI. 47. tigs. 4-6) ;
in such cases the characters are well defined
and luimistakable. It consists of a lenti-
cular body formed of more or less granular
protoplasm, with one or more well- or ill-
defined bright points or cavities (nucleoli) in
the interior. Wherever it appears throughout
the higher plants, it seems to possess the
same characters ; but it ma}' be absent in
the cells of many Algse, Lichens, and
Fungi.

( )rilinarily nuclei are found attached to
the side of cells, or forming the centre of
radiating protoplasmic filaments (PI. 47.
fig. 1)) : sometimes, however, the nucleus is
suspended in the middle of the cavity of
the cell by filamentous processes of proto-
plasm ; in all such cases it forms a kind of
centre for the circulation of the protoplasm
where this exhibits movement (Rotation),
find it is itself carried about to a certain
extent by the currents.

The nucleoli (PI. 47. fig. 8 ») of the.se
larger nuclei are apparently usually more or
less solid granules of a transparent substance,
but sometimes they appear more like minute
cavities.

The nuclei and nucleoli of the lower
plants are exceedingly obscure ; in a great
many cases the so-called nuclei are little
different from the nucleoli of the larger
forms, occupying to the entire cell-contents
the same relation as the nucleoli to large
nuclei, for example, in the spores of Lichens
(PI. 37. fig. 7), Fungi, itc. In the lower
Confervoid Algse the nucleus (or nucleolus)
appears to be represented by the entire cell-
contents (PI. 7), in which one or more well-
defined granules often occur, representing
nucleoli ; in certain stages, however, a larger
granule is met with, coloiu'ed by chloro-
phyll, which some regard as a nuclevis ;
this disappears totally at particulnr epochs,
and is replaced by starch-granules or oil-
globules. The bright-coloured point, or
" eye-spot," seen very generally in the Zoo-
SPOEES both of Confervoids and Fucoids,
may represent a nucleolus.

Nuclei originate in two ways. The sim-
plest mode is found where they precede free-
cell formation, as in the development of
the germinal vesicles in the embryo-sacs of

Flowering plants. Here the nuclei appear
first as globular, granular, or lenticular
masses, which become gradually defined in
the substance of a collection of protoplasm
accumulated at the upper end of the cell
(PI. 47. tigs. 1-4). This is a spontaneous
isolation of a portion of the protojilasm to
become the foundation of a new cell. We
may compare this with the segmentation of
the entire mass of contents of the cells of
Confervae in the formation of Zoospobes,
which may perhaps be regarded as at
first free nuclei. In cells multiplying by
division, a division of existing nuclei has
been observed to take place in certain cases,
as in the hairs of Traclcscantia (PI. 47. figs.
8 & 9) ; but in other .similar cases of division
no nuclei are observed (PI. 47. tigs. 10 k 11).
In Tradcscan/iUfihe oval parent nucleus fills
up the end of the growing cell, so that the
division of tlie nucleus is almost synonymous
with the division of the primordial utricle.
But in this case, as in the development oi
cells from free nuclei, as indicated in the
germinal vesicles, the cell-membrane in
expanding draws away from the nucleus,
which remains adherent to or suspended in
connexion with a layer of protoplasm lining
the cell-wall and forming its primordial
utricle. In Spirogyra and Zi/f/nema, a
division of the free suspended nucleus pre-
cedes the division of the large primordial
utricle.

Mohl describes a division of nuclei as
occurring in Anthoceros ; and most authors
who have written on the development of
pollen and spores lay great stress on the
influence of the nuclei, which they describe;
but the import of nuclei in vegetable cells
is certainly still a problem. Some believe
they are the universal agents of production
of new cells; others that they are not the
agents of this in any case, but, when pi-e-
sent, may be divided with the cells. Others
imagine that they are merely the original
" mould " of protoplasm on which the cel-
lulose membrane of the nascent cell is de-
posited, and which is left unaltered when
this expands (the phenomena in Spirogyra
are opposed to this). Some of those who
deny their influence in cell-development
believe them to be the vital centres of the
cells in which they exist.

They are best seen in very young cells in
all cases ; in nascent tissues they almost or
quite fill the cavit\" of the young cells. As
the cells grow older, their histoiy difl^ers in
dillerent cases. Sometimes they persist

NUMxMULINA.

[ 5i9' ]

ODDNTELLA.

until the decay of the organ in which they
exist. This luippens very generally in the
cells of the ilowers, stems, Sec. of Monoco-
tyledons ; not unfrequeutly, in stems and
leaves they become converted into starch or
chlorophvll granules. In other cases they
have a more definite purpose ; for in the
vesicles in which are formed the spermato-
zoiDs of Ferns, Mosses, Hepaticas, Chara-
ceoe, Sec, these structures appear to be pro-
duced by a metamorphosis of the nuclei.

In examining supposed nuclei of plants,
especially those of lower cellular organiza-
tion, tincture of iodine should always be
applied, to distinguish starch-granules Sec.
from true nuclei, which are always coloured
deep yellow or brownish by that reagent,
besides being coagulated, contracted, and
thcrebv rendered more distinct.

BiBL. R. Brown, Phil. Mag. Dec, 1831 ;
Nageli, Zeit. wiss. Bot. (Ray Soc. 1845 &
1849); Mohl, P/lanzenzelle, 36, 51; Hof-
meister, Entsteh. d. Embryo, 1840, 7; Braun,
Verjimgting {Ray Soc. 1853, 175); Sachs,
Bot. 45; Strassburger, Zp//e/;ij7r/«»(/, 1880.
NUMMULI'NA, D'Orb. I A Hyaline Fo-
NUMMULI'TES,Lamk. ( raminifer of
the highest class. Shell lenticular, varying
in convexity and in size (from less than -g-g
to 2^ inches in diameter), composed of
several, overlapping, uniform, whorls of nu-
merous > -shaped chambers in a discoid
spire. These are prolonged towards the
umbo of each face, thus forming Alar
Lobes, either straight (in the Radiatce),
or sinuous (Sinuafcs), or inosculating (Reti-
culattB). The alse are abortive or absent,
and the spire therefore exposed, in Assi/ina
and Opercidina, unequal and modified in
Amphistegina. The chambers communicate
by a transverse slit at the base of the
septum, with smaller occasional holes. The
outer chamber-walls (Spiral Lamina) are
thin in the latest, but in the older cham-
bers thickened by successive layers of the
delicate tubuliferous shell. Over the septa
of the median plane (PL 24. fig. 22), and
where the alar septa cross and touch, the
tubuli being obsolete, the shell becomes
translucent (Pillars) ; at the outer margin
(Marginal Cord) also of the whorls the
layers of shell become translucent, and are
traversed by radiating and inosculating
tubes, continuous with canals passing be-
tween the two shell-layers of each septum
(Interseptal Canals), and with the canals
in the margin of the inner whorls. This
Canal-system carries spiral and branching

threads of sarcode through the denser parts
of the shell, which, indeed, in some Polysfo-
melhe. and Calcarince app;'ar to be secreted
thereby (Supplementary Skeleton).

Numniulina is rare in the Carboniferous,
Jurassic, and Cretaceous, but very common
in the Lower Tertiary strata ; living in the
North, Red, and Australian seas, but small
{N. rndiata, PI. 24. fig. 21).

BiBL. D' Archiac et Haime, An.foss. Num.
Inde, 1853; Carter, Ann. N. H. ser. 2. xi,
161, ser. 3. viii. 320, 366 ; Parker and Jones,
Ann. N. H. ser. 3. v. 106, viii. p. 229 ; Car-
penter, Foram, 202, Microscope, 1858, 510 ;
Bradv, Ann. N. 11. ser. 4. xiii. 222.

NYCTOTHE'RUS, Leidy.— A genus of
Heterotrichous Infusoria, very near Plagio-
foma. 4 species ; in the intestines of Am-
phibia and Invertebrata. (Kent, Inf. 579.)

NYMPH^EACE.E. See Haibs (p. 379).

O.
OAT, Amna sativa (Nat. Order Grami-
nacepe. Flowering Plants). — The form of
the starch-corpuscles of the oat is very un-
like that of the other common corn-plants ;
they consist of numerous small polygonal
grains grouped together in roundish or oval
masses (PI. 46. fig. 10). See Starch.
OBE'lAX = Laomedea pt.
OBISIDA. See Arachnida.
OBJECT-GLASS, or Objective. See
L\TRODucTioN, p. xvi. & Angflar Aper-
ture, p. 47.

OCEL'LI. — The simple eyes or eye-spots
of the Invertebrata ; they are noticed under
the classes.

OCHLOCH.ETE, Thwaites.-A genus
of Chaetophoraceae. O. hystrix, on grasses
in freshwater and brackish ditches.

OCHROPTERIS, Sm.— A genus of
Pteridefe (Polypodiaceous Ferns). O. jicd-
lens; Mauritius"^ (Hook. Syn. 127.)

OCTAVIA'NA, Tul.— A genus of Gas-
teromycetous Fungi (section Hypogaei) dis-
tinguished by the sterile base of the conti-
nuous or cracked peridium ; the easily
divisible byssoid frames and the fruit-
bearing cavities at first empty, then covered
with the rough spores.

BiBL. Tul. Fung. Hyp. t. ii. f. 1 ; Berk.
Outl. 292 ; Cooke, Handb. 355.

OCTOSPORES.— Sporangia of Fucacese,
which subdivide into a cluster of eight cells.
ODONTELLA, Ag. — This genus of
Dlatomacese is united with Biddxtlphia,
Biddulphia (Odontella) aurita undergoing
spontaneous division, PI. 19. fig. 9.

ODONTHALIA.

[

550

]

CEDOGONIUM.

ODONTHA'LIA, Lyngb.— A genus of
Hhodomelacete (Florideous Algas) coutain-
ing one British species, O. dentuta (PI. 4.
fig. 13), which has an irregularly bipinna-
titid frond, 3 to 12" long, the main axis and
lobes 1-4" wide throughout ; coluur deep
■wdne-red, darker when dried. Frond with
marginal, stalked, ostiolate, ovate ceramidia
with spores, lanceolate stichidia, in which are
contained two rows of ternate tetraspores,
and antheridia.

BiBL. Harv. Alg. 77, pi. 11 A; Phyc. Br.
pi. 34 ; Greville, Aly. Br. pi. 13, Kiitz. Fhijc.
generalis, 448.

ODONTIDIUM, Kutz. — A genus of
Diatomacete.

Char. Frustules quadrangular, united into
an elongated biconvex filament ; linear in
front view; valves elliptical with transverse
continuous striae. Freshwater and marine.
Diifers fi-om Denticida in the elongated
filament, which sometimes, however, con-
sists of only three or four frustules !

O. tunjidulum (PI. 17. tig. 14: a, front
view ; 6, side view). Valves lanceolate,
obtusish ; striae on each valve six ; fresh-
water; length of frustules 1-1720 to 1-570".
O. tahellaria,Suiith = Staurosira construens,
Ehr. (PL 50. tig. 38).

BiBL. Kiitz. BacUl. p. 44 ; Sp.Alg. p. 12 ;
Smith, Brit. Died. ii. 15 ; Rabenh. Fl. Eur.
Alq. i. 116.

ODOXTODIS'CUS, Ehr.— A genus of
Diatomaceae. See Coscikodiscus.

Char. Frustules single, lenticular ; valves
circular, alike, without nodules, covered
with dots arranged either in radiating rows
or in excentrically curved lines, and with
erect marginal teeth. Three species; fossil
and in guano.

O. eccentricus (PI. 18. fig. 52).

BiBL. Ehr. Ber. Berl.Ak. 1844, 73; Kiitz.
Sp. Ah/. 129; Piitchard, Infus.

ODON'TOPHORE. — A new name for
the tongue of the Mollusca; and Radula is
another.

ODONTOTRE'MA, Nyl.— A genus of
Lecideinei (Lichenaceous Lichens).

Char. Tliallus indistinct. Apothecia
black, thelotremoideo-lecideine or gymno-
tremoid, naked, at first closed, then dehiscing
with a denticulato-ruptured proper margin.

O. loiifjias, Nyl. Ou old rails.

BiBL. Leighton, Lich. Flora, 389.

(ECIS'TES, Ehr.— A genus of Rotatoria,
of the family QEcistina.

Char. Single; rotatory organ single,
with an entire margin; body attached to

the bottom of a fixed cylindrical carapace ;
eyes two, frontal, red, disappearing in ad-
vanced age.

O. cnjstallinus (PI. 44. fig. 16). Carapace
hyaline, viscid, covered with foreign bodies;
freshwater; entire length 1-36".

Jaws each with three teeth.

BiBL. Ehr. J/if. 392; Prit chard. Inf.;
Davis, Mic. Tr. 1866, 14; Hudson, Jn. M.
Soc. 1881, 1.

(ECIS'TINA, Ehr.— A family of Rota-
toria (small Melicertcc, probably).

Char. Animals single or aggregate, at-
tached to the bottom of a gelatinous cara-
pace ; rotatory organ single, with an entire
margin.

A distinct carapace for each animal. . . 1 . (Ecistes.
Carapaces ajjgregated into a sphere... 2. Conochilus.

BiBL. Ehr. Infus. 391.

(EDE'iVnUM, Fr.

-A genus of Dematiei

(Hyphomycetous Fungi). CE. a<;-«7«, Corda,
consists of dense tufts of brown erect fibres,
scarcely branched, and without true septa.
The roundish " spores " are sessile upon the
sides of the erect filaments.

BiBL. Corda, Sturm's Deutschl. Fl. 6,
pi. 9 ; Fries, Si/si. Mj/c. 344 ; Berkeley and
Broome, Ann. X. H. 2 ser. vi. 466.

(EDIPODIUM, Schwagr.— A genus of
Splachnaceaj (Acrocarpous Mo.sses), some-
times included under Gymnostvmum. (Edi-
jjodium Grijfitliianum, Schwag., the only
species, is remarkable for the peculiarly
thickened fruit-stalk, whence the name of
the genus is derived.

(EDOGONIACE^.— A family of fila-
mentous Confervoid Algae, remarkable for
the filaments growing by a peculiar mode of
cell-division, accompanied by circumscissile
dehiscence of the parent cell, and by the
zoo.spores being formed from the whole con-
tents and bearing a crown of numerous cilia.
Two genera :

CEdoyonium. Filaments unbranched.

Bulbochate. Filaments branched and
bearing bristle-cells with a bulbous base.

BiBL. See the genera.

(EDOGO'NIUM,Link.(P;-o/i/e;-«,Leclerc,
Veaiculifera, Hass.). — A genus of Qidogo-
niaceaa (Confervoid Algae). Some QlLdoyc-
nia aie among the commonest and most
abundant of freshwater Algie, occiu'iing in
every pond, ditch, or stream, and quickly
making their appearance in tanks, aquaria,
&c. They may generally be recognized at
a glance by the dense and uniform green
protoplasm, sometimes filling the cells,
sometimes (after dividing) leaving half of the

(EDOGONIUM,

[ 551 ]

CEDOGONIUM.

cell colourless aud devoid of chlorophyll —
above all, by the aimular stride occurring at
the euds of 'many of the cells (PI. 9. fig. 7 b,
h). The cells have each a large parietal
nucleus (fig. 7 a). The large round inter-
stitial sporangial cell (fig. 7^) is also a very
distiuctive character. The filaments are at-
tached, when young, to stones, plants, &c.
by root-like processes ; and are composed of
rows of cylindrical cells, which multiply
interstitially in a very curious manner.
When a cell is about to divide, an annular
deposit of cellulose occurs around the upper
part of the parent cell. Next the wall of
the parent cell breaks, by a circumscissile
dehiscence, just below the cellulose ring.
The internal cell elongates aud removes the
margins of the circular slits from each other,
the upper piece of the parent-cell wall being
pushed up as a kind of cap on the elongating
cell. While the cell is thus being elongated,
its primordial utricle becomes divided below
the line of dehiscence of the parent cell ;
but both the new portions grow, so that the
line of division between the two new cells
at length rises above the margin of the
lower part of the parent cell. The annidar
deposit of gelatinous cellulose has mean-
while become stretched or developed over
the space left by the separation of the halves
of the parent membrane, forming an outer
coat to the new cell. After the growth of
the lower cell is finished, the upper one
begins to elongate, until it attains equal
length ; it remains poor in protoplasm and
chlorophyll while growing, but becomes
densely tilled when it has attained its full
dimensions. The margins or broken ends of
the parent-cell wall form the annular striae
seen on the filaments (PL 9. fig. 7 b, (/, h) :
at first there is only one at the top of any
given cell; but the next dehiscence takes
place just below this, giving rise to a second,
and so on, until many successive rings are
produced at one spot.

The zoospores or ciliated gonidia (fig. 7 c)
are formed from the entire contents of a
cell, and exhibit a large round nucleus;
t'.iey escape by a circumscissile dehiscence
of the wall of the parent cell (6) : the fila-
ment, however, does not generally become
quite broken in two ; the portions remain
attached by a strip of the side-wall forming
a kind of hinge ; and the zoospores are not
set free directly, but at first are enclosed in
a very delicate and almost imperceptible
globular envelope, colorable blue by iodine
and sulphuric acid, which appears to dis-

solve very quickly in the water. The zoo-
spores are large, somewhat ovate in form,
with a transparent region at one end, whence
the numerous cilia arise. When expelled,
they move for a time, and then come to rest,
attaching themselves to foreign objects by
the ciliated end, acquiring a membrane,
sending out root-like processes below {e),
and elongating and expanding above into a
longish pear-shaped body. Sometimes the
zoospores do not completely extricate them-
selves from the parent cell, and then ger-
minate in this way in situ, the root-like
processes remaining engaged in the parent
cell. Very often they attach themselves
upon the parent filament to germinate. The
next stage after germination presents two
difTerent classes of phenomena : in the one
case, as a purely vegetative zoospore, the
young plant elongates gradually into a
jointed filament by extension and cell-
division ; in the other it is an androspore,
and becomes an antheridial filament.

The (Edoyonia produce large resting-
spores (oospores or oogonia), which are
formed from the entire contents of the
uppermost of two cells developed as above
described. A rupture of the parent-cell
wall takes place at the side during the
development of the spores ; through the
small orifice thus formed the spore-mass
becomes fertilized through the agency of
the little globular bodies produced in the
autheridia (PL 5. figs. 5, 16, 17). Ulti-
mately the spore, while increasing in size,
retracts itself from the walls of its parent
cell {oor/oniuiii), and lies free in the cavity,
presenting a double coat, the outer of which
is thick and tough ; its contents acquire a
red colour as it ripens. The parent cell of
the spore mostly acquires a globular or
elliptical form, and a red or brown colour,
appearing like a kind of nodule on the fila-
ment ; and the ripe spore, of globular elli|D-
tical, or depressed spherical form, is mostly
of greater diameter than the ordinary cells
(PL 5. fig. 21). The ripe spore, which is
quadruple, escapes by the decomposition or
dehiscence of the parent cell, and is covered
with a hyaline membrane. Each of the
four spores is likewise surrounded by its
ceU-membrane. After a short time has
elapsed, the hyaline membrane disappears,
and the four spores lie still and motionless.
Then a change sets in : the cell-membrane
of each spore bursts by means of an annular
slit, and a part separates like a lid. Soon
the cell-contents leave the ceU in the form

(EDOGONIUM.

[ 552 ]

CEDOGONIUM.

of a zoospore, which moves with the aid of
a crown of cilia. Alter a time the motion
ceases, the cilia disappear, and one end of
the zoospore becomes elongated into a root
like the ordinary zoos]wres. The little cell
thus fixed becomes di\ided bj a transverse
septum. Each spore thus produces four
CEdof/onmm plants.

The antheridial structures of the CEdo-
gonia are either formed in the ordinary fila-
ments (PI. 5. fig. 13), or from dv\ arf fila-
ments produced from the smaller zoospores
or androspores (PI. 5. fig. 10). In either
case they consist of one or more very short
joints of the filament, formed in the ordi-
nary way, the contents of which divide
into two portions. The cells then dehisce
and allow the new products to escape, which
resemble the vegetative zoospores, but are
much smaller. These new bodies, the
spermatozoids, make their way through the
orifices in the parent cells of the spores and
fertilize their contents (PL o. fig. 20).

Some of the larger spermatozoids move
like Amahce, creeping over the oospore,
until they I'each the canal, into which
they enter.

The Qidogonia appear to be sometimes
purely monoecious or dioecious, the single
filaments including eitlier both antheridial
and spore-cells, or only one kind of organ ;
bat the most common condition is interme-
diate : the filaments having some joints
converted into sporangial cells, others
giving birth to the androspores, which
germinate into dwarf antheridial filaments,
often sessile on or near the sporanges,
which produce spermatozoids. This con-
dition is termed bj' Pringsheim gynandro-

Sj}07'OUS.

The systematic arrangement of the
species is difficult on account of the vari-
ability in the size of the filaments. Prings-
heim makes the following arrangement: —

* Spores globular.
t Sporanges opening by a valvular lid.

CE. rostellatum. Sporange oval, spore
globular, not filling the sporange, An-
theridia 3- or 4-celled. Monoecious.

tt Sporanges opening by a lateral orifice.
\ Monoccions.

(E. curvum. Sporanges depressed, orifice
in the middle line ; spores completely
filling the sporanges, and of the same form.
Antheridia 3- and 4-celled.

(E. tumiduhtm. Sporange ovate, orifice
in the upper half; spore globular, not
fillinof the sporange. Antheridia mostly
2-ceUed.

XX Gynandrospurous.

CE. Rothii. Dwarf male plant straight,
sessile on the sporange, without a spreading
base. Sporange ovate, expanded in the
middle ; orifice in the middle line ; spores
depr£ssed, filling the inflated part of the
sporange.

GL. depressum. Male plant straight, sessile
on the sporange, with a foot and internal
1-celled antheridia. Sporange depressed,
orifice in the middle line ; spores of the
form of the spoi-ange. not filling it.

CE. Braunii. Male plant curved, with a
foot and 1-celled antheridium. Sporange
oval, iuflated in the middle ; spore globular,
not filling the sporange.

CE. ecliinospermnnt. Male plant almost
straight, sessile on the cell below the
sporange, with foot and outer 1-celled an-
theridium. Sporange oval, orifice in the
lower half: spore globular, spinous.

** Spores oval.

t Sporanges opening by a circular lid.

X Gynandrosjjorous,

CE. ciliafinn. Male curved, sessile on the
sporange, with foot and outer 1-celled
sporangium. Spores oval, filling the broken
portion of the sporange.

tt Sjwranges opening by n lateral orifce.
X Ciynandrosporous.

CE. apophysatvm. Male plant curvid,
sessile below the sporange, and outer 2-
ranked antheridium. Sporange oval, orifice
in the upper half; spore filling the sporange
up to the cap-like part.

XX Dioecious.

CE. gomellipariuni. Male plants more
slender than the female ; anthei'idia monv-
rowed ; septa of the parent cells perpen-
dicular to the other cell-septa. Sporange
oval, orifice in the upper half, the spore
filling it completely to the cap-portion.
Filaments ending in seA'eral almost hyaline
elongated cells, without a terminal bristle.

BiBL. Mohl, Bot. Ze.it. xiii. 689 ; De Bary,
Soc. Sc. Nat. Fribotire/, 1856 ; Carter, Ann.
N. II. 3 ser. i. 29 ; Ilassall,'^/^. 195 : Eraun,
Kiitz. Sp. Alg.; Eabenh. Alg. iii. 347;
Juranyi, Pringshei7ns Jahrb. 1873 ; Prings-

OIDIUM.

[ 553 ]

ONCOBRYSA.

lieiiii, Jahrb. i. 1 ; De Bary, A7in. Sc. N. 4
s^r. V. 262 ; Sachs, Bot. 281.

OID'IUM, Link ( Acrosporium ?ir\A. Spoi-o-
tru'/nim, Greville ; Torula, Corda). — A sup-
posed geuus of Mucedines (Hj^phomycetous
Fungi), but very probably consisting of
imperfect conditions of plants of more
complex nature. The Oidia have recently
attracted great attention on account of the
extraordinary development of the form
called Oidiuin Tuckeri on the vines of Eu-
rope and the Atlantia islands. This, how-
ever, like O. leticoconiion and others, appears
to be only the conidiiferous mycelium of an
Erysiphe or some allied plant ; the parti-
culars of its history are given more at length
under Vixe-Fungus. Oidi'mn lacfis seems
also referable to Torula, or to the myce-
lium of PENiciLLitTM, O. abort if (icims ,
Lk., is an imperfect state of Cla^iceps ; O.
albicavs, Robin, the fungus of Aphtha,
is probably referable to some other genus
when mature, as Achorion should perhaps
also be included under Penicillium. The
objects described as Oidia consist of delicate
horizontal filaments, creeping over leaves,
fruits, or decaying vegetable and animal
substances (O. lactis at the edges of sour
milk, O. albicans in the mouth of the hu-
man subject), forming an interlaced fleecy
coat, the horizontal filaments giving origin
to numerous erect, usually short, articu-
lated pedicels, the uppermost cells of which
(or several of the uppermost) expand into
oval bodies (conidia) which become dis-
articulated, and, falling upon the matrix,
germinate and produce new filaments (PI. 26.
figs. 8-11 ).

Oiditim leucoconimn, Tuckeri, erysiplioides
are white ; O. aureum,fiilTvm,fructigen%im,
and others subsequently become coloured,
and these certainly belong to a different
categorv.

BiBL. Berk. Hook. Br. Fl. ii. pt. 2. 349 ;
Ann. N. H. i. 263, vi. 438, 2 ser. vii. 178,
xiii. 463 ; Crypt. Bot. 300, 308; Fries, Smn.
Vet/. 494 ; Fresenius, Beitr. z. Mycol. H. i.
23, ii. 76 ; Leveille, Ann. Sc. Nat. 3 ser. xv.
109; Grev., Crj/pt. i^/.pl.73; Puibin, Vcr/et.
Par. 2nd ed. 488 ; and the Bibl. of Vine-

FUNGTTS.

OIKOM'ONAS, Kt.— A genus of Flagel-
late Infusoria. Exceedingly minute, ovate,
flagellum single ; a thread-like process pro-
truded at will from the posterior part of
the body, serving for attacliment. Six
species; in infusions, fresh- and salt-water.
(Kent, Inf. 250).

OIL. — Oils of various kinds are most
abundantly produced by a very large num-
ber of plants, and occur to some extent in
almost all. For the microscopist, it is con-
venient to divide them into essciitial and
fixed oils. The former are special secre-
tions, and occur in the cells of the Glands
and Glandular Hairs of the epidermis of
those parts of plants exposed to the air and
light. Fixed oils are found principally in
the cells of tissues stiU physiologically
active in the nutrition of the plants, and
they appear in many cases to have a close
relation with and to form substitutes for
starch. Thus fixed oils occur stored up in
the cells of the perisperms or of the cotyle-
dons of certain seeds in which little or no
starch is produced, as in the Papaveracecs,
Cruciferce, Liniim, the almond, nut, &c.
Oil may occur also in the pulp of fruits, as
in the olive.

Spores of Cryptogamic plants and Pol-
LEN-grains are remarkable for tlie oil they
exhibit in their mature condition. It ap-
pears to serve as an indifferent or inert form
of assimilated nutriment.

Oil occurs in the cavity of cells in the
form of minute drops, which may be dis-
tinguished mostly, by the experienced mi-
croscopist, by simple inspection ; but it is
often desirable to prove the nature of the
globules, which may be done by removing
them with benzole, or, in the case of pollen,
by viewing them in spirit of turpentine or
oil of lemon.

OI'THONA, Baird.— A genus of Cope-
podous Entomostraca. O. spiiiiferus ; marine.
(Bradv, Copep., Pai/ Soc. i. 90.)

OLEAN'DRA, 'Cav.-A geuus of As-
pidieae (Polypodiaceous Ferns). 6 species j
tropical. (Hook. Sijn. 302.)

OLTGOCLASE. See Rocks.

OLPIDTUM, Braun.— Like Chytridium,
but without operculum or rootlet, elongated
into a cylindrical tube ; epi- or entophytic,
on freshwater Algje ; O. simidans, in the
living leaves of the dandelion. ( Rabeuhorst,
Air/, iii. 282.)

OMPHALOPEL'TA, Ehr.— A genus of
fossil Diatomaceoe which agrees with Acti-
noptyclins.

O. areolata (PI. 18. fig. 53).

Bibl. Ehr. Ber. Berl. Ak. 1844, 263;
Kiitz. Sp. Aly. 132; Grev. Mic. Tr. 1866,
122.

ONCOBRY'SA, Agardh {Hydrococcus,
Kiitz.). — A genus of Palmellacere. Fronds
minute, hardish ; cells in rows, the super-

ONCOSPHENIA.

[ 554 ]

OOGONIUM.

ficiiil ones crowded, forming a cortical layer.
3 species, brownish-green or purplish ; on
submersed wood and mosses. (Rabenh.
Alq. ii. 67.)

ONCOSPHE'NIA, Ehr.— A genus of
Diatomacese.

O. carpathica. Valves laxly striated, one
end turgid, rounded, and straight ; the other
attenuate and uncinate ; freshwater ; diam.
1-790".

BiBL. Ehr. Ber. Bed. Ak. 1845, 72;
Kutz. Sp. Alff. 11 : Rabenh. Alg. i. 296.

ONIOX, Allium Cepa (Flowering Plants,
Nat. Ord. Liliacefe). — The young bulb of the
onion offers a very good and cheap subject
for the investigation of the development of
spiral vessels, to those who do not object to
its odour ; other bulbs will do equally well.
In the cells of the base of the bulb occur
very elegant groups of prismatic crystals
(see Raphides).

ONOCLEA, Sw.— A genus of Dick-
sonieoe (Polypodiaceous Ferns). Sori dorsal,
globose, on the veins of changed contracted
pinnae of the fertile fronds, and concealed by
their revolute margins. 3 species; cold or
temperate climates. (Hook. Si/ii. 45.)

ONYCH'IUM, Kaulf.— A genus of
Pterideae (Polypodiaceous Ferns). Four
species ; tropical. (Hook. Si/7i. 143.)

ONYCHODROMUS, Stein.— A genus of
Hypotrichous Infusoria. Like Stylonichia,
but the ventral styles linear, and the caudal
setae absent. O. grandis; freshwater.
(Kent, Lif. 766.)

ONYGE'NEl.— A family of Ascomyce-
tous Fungi, containing a few inconspicuous
plants growing upon the feathers of dead
birds, or upon cast-oif hoofs and horns. The
flocculent spreading mycelium usually pro-
duces on its surface little white stalk-hke
bodies crowned by a globular perithecium.
At first erect and thick, these supports be-
come more slender as they elongate, and
seem to bend under the weight of the light
perithecium (fig. 531). In some species the
perithecium is sessile. The perithecium is
filled with branching filaments, arising from
the walls of its internal cavity, interlacing
together and bearing at their free extremi-
ties globular cells (asci) containing the
spores (figs. 533, 535). At the epoch of
maturity the perithecium, originally closed,
bursts circularly towards the b.ase, the upper
part becoming detached under the form of
a more or less regular cap (fig. 632), expo-
sing the spores set free by a solution of the
filaments.

Fig. 531.

Fig. 532.

Fig. 5.33.

Fig. 534.

.^^j^m^

Onygena corviua.
Fig. 531. Plants on a featht-r. Nat. size.
Fig. 532. Single plant with the perithecium dehiscing.

Maga. 10 diams.
Fig. 533. Portion of the sporiferous layer, with asci.

Magn. 350 diams.
Fig. 53-1. Asci detached. Magn. 700 diams.
Fig. 535. Spores. Mag. 700 diams.

British Genus.

Omjgena. Perithecium capitate, at length
slit round the base, and falling off as an
imperforate cap. Asci borne at the free
ends of filaments forming an entangled mass
in the perithecium, finally free and pulvera-
ceous.

BiBL. Berk. Br. Fl. ii. pt. 2. 322; Anyt.
N. H. vi. 432, 2nd ser. vii. 184; Tulasne,
Ann. Sc. Nat. 3 ser. i. 367, pi. 17 ; Greville,
Crypt- Fl. pi. 343 ; Cooke, Hando. 641.

OOC AR'DIUM, K(^g., = Inomerin.

OOCYS'TIS, Nag.— Agenus of Palmel-
laceous Algae, probably identical with
Nephrocyfimn.

BiBL. Rabenh. Fl. Eur. Aly. iii. 52.

OOGO'NIUM. — A term sometimes used
to signify the parent cell of a true female
spore.

OOLITE,

[ 555 ]

OPERCULINA.

OOLITE, or hoestone, is the substance
of oolitic rocks, aud consists of carbonate of
lime, partly crystallized, partly granular;
the granules usually include organic remains,
as broken shell, &c. It consists of two
parts, one of which, forming the matrix, is
mostly colourless, often crystalline, and
exhibits a number of round or oval cavities,
each of which contains a nodular granule
of a corresponding form. The nodides are
sometimes coloured, rarely hollow, and
often exhibit concentric rings like those of
calcidi, and indicative of the successive
deposition of layers. Sometimes a Forami-
nifer, but more often an organic fragment, or
grain of sand, forms the nucleus of the
grain.

Polished sections of oolite form interest-
ing objects; aud where the nodules are
coloured and the matrix colourless, as in
oolite from Bristol, in which the former are
red, the beauty of the appearance is in-
creased.

See Rocks.

OOMY'CES, Berk, and Br.— A genus of
Pyrenomycetes (Ascomycetous Fungi),
founded on a minute plant growing upon
the leaves of grasses. O. carneo-allus,
{Sphceria carneo-alha, Libert) has pale,
flesh-coloured, tough receptacles 1-18" high,
marked with the ostioles of 3-7 perithecia
closely packed within it, bearing resemblance
to the eggs of some insects.

BiBL. Berk, and Broome, Ann. Nat, Hist.
2 ser. vii. p. ISo.

OOSPORE.— A term used to indicate a
spore which is impregnated before germina-
tion, as in CEdoffoniiwi ; and also applied to
the larger form of spore in Selagi^jella
and IsoETES.

OPAL. — A siUceous mineral. There are
many varieties, thin sections of which
present interesting objects for the micro-
scope and microspectroscope. Wood opal
is wood petrified w ith hydrated silica, and
is light and not very hard. It exhibits in
some places vegetable structure. Other
opals contain the remains of substances
which may be of vegetable origin, or of
minerals which simulate such organisms.

BiEE. Dana, Mineral. ; Slack, 31. Mic.
Jn. 1873, 105 ; Zirkel, Mineral. &c. 112.
See Agate.

OPALI'NA, Purk. and Val.— The ani-
mals comprised under this title were for-
merly regarded as Infusoria ; but later re-
searches tend to show that many are im-
perfectly developed forms or intermediate

stages of higher animals. They are micro-
scopic, oval or oblong, colourless, covered
with vibratile cilia arranged in regular rows.
Some contain a nucleus, and exhibit coa-
tractile vesicles ; but they do not admit
colouring-matters, nor have they a mouth.
In one form an adhesive suctorial disk has
been observed, and in another a hook-
apparatus, probably serving the same end.
They are parasitic vvithiu the bodies, usually
the intestinal canal, of earth-worms, frogs,
Planari<s, Naides, beneath the gill-plates
of Gammarus, &c.

O. (Bursuria, F.) ranarum, is figured in
PL 31. fig. 47.

BiBL. Purkinje and Valentin, De mot,
vibr. ; Schultze, Turhell. ; Stein, Inf. ; Cla-
parede et Lachmann, Etudes, 373 ; Lan-
kester, Qu. M. Jn. 1870, 143; Kent, Inf. 558.

OPEG'RAPHA, Ach.— A genus of Gra-
phidese (Lichenaceous Lichens), gi'owing on
bark of trees, stones, &c. Besides their
linear lirellce., the fronds bear spermogonia,
in O. varia and O. calcarea forming black
spots on the surface, communicating with
little unilocular cavities lined with short
linear sterigmata bearing numerous sper-
matia. Several species.

BiBL. Br. Fl. ii. pt. 1. 147 ; Tulasne,
Ann. Set. Nat. 3 ser. xvii. 207 ; Leighton,
Lich. Flora, 395.

OPERCUL AREL'LA , Hincks, = Cam-
panidaria pt. (Hincks, Hyd. Zooph. 193.)

OPERCULA'RIA, Goldfuss.— A doubt-
ful genus of Vorticellina, now included in
Epistylis.

O. articnlata, E. Found adherent to Hy-
dropldlus piceus and F)ytiscus maryinalis.
PI. 32. fig. 25.

O. lerberina, St. Found upon Noterus
crassicornis, a water-beetle.

Other species, on Entomostraca, &c.

BiBL. Ehr. Infus. 286 ; Stein, Lifus. ;
Clapai ede et Lachmann, Etudes, 111; Kent,
Inf. 710.

OPERCULI'NA, D'Orb.— A Nummuline
Foraminifer. Shell flat, discoidal, many-
chambered ; spire exposed, and whorls
rapidly increasing in width. The shell-
structure of O. arabica, Carter, is described
at p. 330 (PI. 24. figs. 23-26), Rare in the
Chalk, and abundant in many Tertiaiy beds.
Large and plentiful in the East-Indian and
South seas; common, but small, in the
northern seas.

BiBL. Williamson, Tr. 3Iicr. S. ii. 159
(" Nonionina''); Carter, Ann. N. H. 2. x.
101, 3. viii. 311; Carpenter, Phil. Tr.lSoQ;

OPHIDOMONAS.

[ 006 ]

OPHRYDIUM.

For. 247 ; Parker and Jones, Ann. N, H.
3. viii. 229.

OPHIDOM'ONAS, Ehr.— Agenericname
applied to slender, filiform, spiral (helical),
Fi'i/v'o-like bodies, of a brown or red colonr,
■with obtuse ends, and actively moving
through the water by means of an anterior
flagelliform filament. Ehrenberg places
them among the Infusoria, in the family
Cryptomonadina, and admits two species,
characterized by the difterence in colour.
One was found in fresh, the other in brack-
ish water. Length about 1-570", breadth
1-9000". In some the spire forms . >nly half
a turn, in others two and a hall' turns.

Probably an Alga. Is it the young state
of Spirulina ?

BiBL. Ehr. Infus. 43, and Ber. Berl. Ak.

-A genus of

1840 ; Kent, Inf. 244.

OPIirOCLES, Hincks.
Hydroid Zoophytes.

Char. Stem branching, rooted by a creep-
ing stolon, capsules vase-shaped ; polypes
not retractile ; body d-^eply constricted a
little below the base of the tentacles, which
surround a conical proboscis. Tentaculoid
organs borne on the stem and stolon, highly
extensile. Reproduction by fixed spore-
sacs.

BiBL. Hincks, Brit. Hifd. Zooph. 230.

OPHIOCY'TIUM, Nkg.— A genus of
Unicellular Algse.

Char. Cells free, single, vermiculate, ob-
tuse at one end, mucronate at the other.

O. majus (PI. o. fig. 11), on freshwater
plants.

BiBL. Pabenh. AI(/. iii. 66.

OPHIO'DES, Murr.— A genus of Ixodea
(Acarina). Body thin, flat, circular ; on
foreign snakes. (Murrav, Be. Bnt. 203.)

OPHIO'DES, Hincks.— A genus of Hy-
droid Zoophytes. O mirabilis,onLaminaria
&c. (Hincks, Zooph. 230).

OPHIOGLOSSA'CE^.— An Order of
Ferns, distinguished from all others by the
characters both of the vegetative and re-
productive structures. Fronds divided into
two parts, one fohaceous and sterile, the
other fertile, neither being rolled up in the
form of a crook. Sporanges destitute of
annulus, and split transversely nearly to the
base.

Ophioglossuvx. Sporangia sessile, in two
rows, forming a narrow spike,

Hehninthosfachys. S])orangia in crested
clusters, forming a long loose spike.

BotrycMuin. Sporangia sessile, in two
rows on the spikes which form a panicle.

OPHIOGLOS'SUM, Linn.— The typical
genus of Ophioglossaceous Ferns, repre-
sented by the Adder's-tongue Fern, Ophio-
c/lossum vulgatum. Other tropical species.
(Hook. S)/n. 444.)

OPHIONEL'LA, Kt.— A genus of Peri-
trichous Infusoria. Solitary, elongate,
pesistome as in Vorticella ; contained in a
soft sheath. O. ««fte : freshwater. (Kent,
Inf. 734.)

"OPHIOTHE'CA, Curr.— A genus of
Myxogastrous Fungi, distinguished bv a
simple perldium bursting longitudinally ;
capillitium twofold, viz. hyaline articu-
lated threads, to which the spores are at-
tached, and echinulate thicker branched
filaments.

O. chrt/sosperma occurs on the inner bark
of dead trees.

Bmu. Curr. Qu. Mic. Jn. ii. 240; Berk.
Oxitl. 310 ; Cook, Hanclb. 402.

OPHRYDI'NA, Ehr.— A doubtful family
of Infusoria, corresponding to Vorticellina
with a carapace.

Animals grouped in a gelatinous mags ... Ophrydium.
'Body atta'.-hed to the bottom ) ~. ,.

pace by a stalk... f^'" '"'""*•

i.als J o

Anim.alsJ of the carapa

single, j Body not j Carapace stalked... Coihurnia.
( stalked. "( Carapace sessile ... Vaginicola.

BiBL. Ehr. Infus. 291 ; Clap, et Lach.
Etudes, 03.

OPHRYD'IUM, Ehr.— A genus of Perl-
trichous Infusoria,, family Vorticellina.

Char. Consists of a colourless, gelatinous,
rounded mass, either adherent or free, con-
taining numerous greenish VorticeUa-\\kQ
animals imbedded and somewhat rad lately
arranged within it ; freshwater. Lenjjth cif
extended bodies 1-100" ; size of entire mass
from that of a pea to that of the fist, and
even more.

O. versatile (PL 31. fig. 49, portion near
the surface ; fig. 48, portion expanded by
pressure ; fig. 50, separate animal). The
gelatinous mass or envelope has been de-
scribed as con.«isting of separate portions or
cells, and again as forming a homogeneous
whole. It somewhat resembles and hrs
been mistaken for frog's spawn. The body
exhibits annular con.strictions and longi-
tudinal folds, and contains scattered chloro-
pliyll-grannles, and a long, narrow, tortuous
nucleus. A distinct narrow elongated
oesophagus is present. Ehrenberg remarks
that at first the indindual bodies are united
in the centre by filaments, which subse-
quently disappear. The animals undergo

OPHRYOCEUriNA.

[ 557 ]

ORBULINA.

the encystiiiji- process; when they leave the
jelly, a'posterior ring of cilia is formed, as
iu Vortkella, aud the aiiimids swiui with
the tail tirst.

This organism bears some resemblance to
CoccocMoris among the Palmellacese, yet it
appears decidedly animal.
O. EivhorHii, on Anacharis.
BiBL. Ehr. In/us. 292 ; Stein, In f. ; Cla-
parede et hachmanu, Etudes ■ Kent, Inf. 735.
OPHRYOCEKCINA, Ehr.— A 'family
of In fii soria . See Th ac heli x a.

OPHRYODEN'DRON, Clap, et Each.—
A genus of Acinetina.

C/iar. Acinetina with the suckers at-
tached to a long retractile proboscis.
Six species ; marine.
(). ahitiimim, on Ciunpnnularia.
BiBL. Clap, et Each. Etudes^ 381 ; Kent,
Inf. 849.

"OPHRYOGEE NA, Ehr.—A genus of
Holotrichous Infusoria, of the family Bursa-
rina.

Char. Ovate ; a fronial eye-spot ; cilia in
longitudinal rows; a watch-glass-shaped
vibratile membrane near the muuth. Fresh-
water.

Five species. Stein remarks that, on
treating these animals with acetic acid, the
cilia became converted into a dense network
of curved and geniculate hairs, some as long
as the bodv.

0.atra\V\. 31. fig. 51). Body ovate,
compressed, black, acute posteriorly ; eye-
spot black, marginal ; cilia whitish ; length
1-180".

O. acuminata, brown ; eye-spot red.
O.Jlavicatis, yellowi.-h ; eve-spot red.
BiBL. Ehr. Inf. 360; Stein, Inf. 240;
Diij. Inf. 506; Lieberkiihn, Ann. N. H.
1866, x\-iii. 319 ; Claparede et Lachmanu,
Etudes, 256 ; Kent, Inf. 532.

OPHRYOSCO'EEX, St.— A genus of
Peritrichous Infusoria. Free, ovate-elon-
gate, with a Vorticella-Yike peristome ;
middle of the back surrounded by a row of
stout setEe ; a long posterior style-like pro-
cess. 2 species ; in the rumen aud reticulum
of ruminants. (Kent, Inf. 652.)

OPISTHIOT'KICHA, Perty.— A genus
of Infusoria.

Char. Small, .cylindrical or pyriform.
Cilia on body fine, those on posterior part
large. 0. tenuis, in bog-pools.
BiBT.. Pertv, Lebensf. 150.
OPIS'THO'DOX, St*ein.—A genus of Hy-
potrichous Infusoria. Free, ovate, dorsally
convex, vcj lically plane, t jlialc ; mouth

near the posterior half, w-ith a cylindrical
rod-fascicle. O. niemeccerms ; freshwater.
(Kent, Inf. 749. )

OPISTIIOTRICiriA, Kt.— A genus of
llypotrichous Infusoria. Free, ovate ;
frontal, ventral, aud anal styles as in Ojci/-
triclui, also with caudal setas. 2 species j
freshwater. (Kent, Inf. 785.)

ORBICUEI'NA, Eamk.— A genus of
porcellaneous Foraminifera. Discoidal, equi-
lateral, greatly compressed, very variable
according to age; forming an embracing,
very regular spire when young, subse-
quently growing into a more or less perfect
disk, almost uudistinguishable from Orhito-
lites. Chambers very narrow, curved, and
divided throughout their length into nu-
merous minute cavities (chamberlets) by
perpendicidar partitions, transverse to the
spiral coil. Orifices very numerous, round,
in rows along the septal plane on the outer
margin of the shell.

Living in tropical seas (O. odunca, PI. 23.
fig. 19) ; fossil in the Tertiaries.

BiBL. Carpenter, Phil. 1): 1856, 547;
For. 93.

ORBITOrpES, D'Orb.— One of the hya-
line Foraminifera, related to NummuUtes
and often mistaken for it. Eenticular ;
thick or thin ; smooth, granular, or radiate ;
composed of a median plane of chamberlets
arranged cyclically, and of very numerous
layers of compressed chamberlets above and
below.

Fossil only ; in the Upper Chalk, and
Eower and Middle Tertiaries.

BiBL. Gumbel, Abh. baijer. Ale. 1868, x.
070.

ORBITOEI'NA. See Patellixa aud

POKOSPH^RA.

ORBITOLI'TES, Lamarck (Orbulites).—
Aporcellaneous Foraminifer, nearOrbicidina,
but distinguished by the chambers being
arranged in concentric circles.

Inhabiting tropical seas.

O. complanaius (PI. 23. fig. 17) — Sorites
and Amjjhisonts, Ehr. ; fossil in the Lias,
Chalk, and Tertiaries.

BiBL. Morris, Brit. Foss. 39 ; Carpenter,
Phil. Tr. 1856, 181 ; For. 105.

ORBULI'NA, D'Orb.- A hyahne Fora-
minifer, consisting either of a single spheri-
cal chamber, or of a large globular chamber
enclosing a small Globigerine group of
earliercells. Perforations numerous, minute
and of two sizes; but single orifice doubtful.
O. uni versa CPl. 24. fig. 1). Recent, and
fossil as far back as the Lias,

ORGANIZATION.

[ 558 ]

ORIBATEA.

BiBL. D'Orbigny, -For. Vien.22; William-
son, See. For. 2 ; Carpenter, For. 17G ;
Alcock, 3Iem. Lit. Phil. Manch. 3. iii. 178 ;
S. Owen, J. Linn. Soc. Zool. ix. 149; Ter-
quem, iJfe'OT. Mefz, 1862, 432; Brady, Qii.
Mic. Jn. n. s. xix. 75.

ORGANIZATION AND VASCULA-
RIZATION.— Immediate reimion of cut
surfaces may take place without any exuda-
tion ; but in healing' by what is termed the
fi]"st intention, a substance is present which
g'lues the edges of the wound together.
This consists of the connective tissue of the
Gut surface, infiltrated with blood-corpuscles
and serum, and swollen by the imbibition
of the latter. The next stage of the pro-
cess is the migration of colourless corpuscles
from the dilated vessels in the immediate
neighbourhood. They permeate the whole
of the cementing medium and the adjacent
connective tissue, so that the divided parts
are at length united by a continuous layer
of embryonic tissue. The next step is the
reestabli'shment of the circulation. Thiersch
found the cut ends of the vessels a few
hours after the injury plugged by a cor-
puscular proliferation and somewhat dilated,
but seldom occupied by a blood-clot. In-
jecting the vessels at this stage with a warm
sohition of gelatin, and hardening the speci-
men in alcohol, he found sticking to the
surface of the club-shaped plug of gelatin,
endothelial cells, some detached and isolated,
others undergoing proliferation. Moreover
he found a peculiar configuration of the
surface of the plug, in which were the
radicles of a very beautifid system of inter-
cellular canals, forming a provisional nu-
trient apparatus. The last act is the trans-
formation of that part of the embryonic
tissue which is not employed in the con-
struction of vessels, into fibrous connective
tissue. Should pus be forined in a wound,
healing by the second intention occurs (see
Pus). Pus is given oft" from the wound,
and from its surface young cells force their
wav from countless points ; they are accom-
panied by a fluid mainly transmitted from
the blood, and very rich in dissolved nj-
buminous matters. 'Sooner or later the cells
close up their ranks, and a layer of em-
bryonic tissue is formed, which intervenes
between the parenchyma of the organism
on the one hand and "tlie pus on the other.
Then this embryonal connective tissue gets
thicker, rises into small globular projections
or granulations ; they produce both skin and
cuticle, and new vessels. Along certain

lines running through the parenchyma in
which these new vessels are to be, a closer
aggregation of the cells becomes apparent;
a cord or row of cells becomes visible,
pointing out the form and direction of the
future blood-path. Soon the blood makes
its appearance in the axis of the cellular
cord, and the cells parted asunder begin to
constitute the wall of a new blood-vessel.
As each layer of embryonal tissue is formed
on the surface, rows of cells aggregate as
above, and new vessels are completed. As
the cicatrical tissue contracts after its for-
mation out of the embryonal tissue, and as
it is fashioned at the deepest part of the
wound, first the whole of the raw surface
shrinks and compresses the vessels, obliterat
ting many and reducing the vascularity of
the healing tissues.

_ ORIB'ATA, Latr.— A genus of Oriba-
tidee, of which there are several species, on
stones and plants. Some are common.

The position of three species is doubtful,
viz. Acarus confervce, Schr., freshwater,
creeping upon Confervse, &c. ; Oribata de-
mersa, Duj., with a cervical eye, upon
Hyimum inunclatum ; and Oribaia marina,
a marine species.

BiBL. Gervais, Walch. Apt. iii. 251 ;
Schrank, Iris. Amtrice, 511 ; Duiardin,
rinstit. 1842, 316 ; Koch, Detdschl 'Cntst. ;
Duges, Ann. Sc. Kat. 2. ser. ii. 46 ; Murray,
Fc^Fnt. 217.

ORIBATEA.— A family of Acarina.

C7iar. Body covered by a hard horny
dark envelope; palpi fusiform, 5-joiflted ;
first joint small, second large, inflated and
almost half the length of the entire palpus,
palpi hairy outside only ; mandibles chelate;
body often winged ; no suckers. Genera :

NuthrKs. Body elongate, Irregularly
quadrilateral, with spinous filaments ; logs
of moderate length, thick, tarsi with 3
homodactyle claws.

Belba. Abdomen distinct from thorax,
rounded, inflated; legs long, geniculate,
with 1 claw.

Oribata. Cephalothorax with lamellar
appendages ; tarsi with 3 heterodactyle
claws ; hairs bristle-shaped.

Cepheus. Cephalothorax lamellar ; claws
3, alike.

Notaspis. Cephalothorax lamellar, tectum
confounded with it.

Leioso7na. Cephalothorax with plates,
claws 3, heterodactyle.

Pelops: Like Oribata, but hairs flat and
spatula-shaped.

ORNITHOBIUS.

■[ 559 ]

ORTIIOTRICIIUM.

ncrmannia. Ceplialothorax soldered to
abdomen ; tarsi with 1 claw.

Eremccus. Cephalothorax simple ; tarsi
with 3 heterodactyle claws.

Damcvus. Cephalothorax ribbed, legs
long'er than the body, 1 claw.

Galumna. Abdomen siibglobidar, de-
pressed, margins of the pseudothorax
winged ; legs of moderate length.

Hoplophora. As the last, but wing-like
appendages absent ; tarsi 1-clawed.

BiBL. Walclc€7iaer' s Apth'cs, 251 ; Koch,
DeufschL Crustac. ; Duges, Ann. Sc. JVaf. ii.
48 ; Diifour, Ann. Sc. Nat 1 ser. xxv. 289 ;
Mcolet, Archiv d. Mii^exm, 1855 ; Michael,
M. M. S. 1879, 225, 1880, 32, 177.

ORXITHO'BIUS, Denny.— A genus of
Anoplura. Like Ninnus, but with 2 horns
to the clypeus. O. cygni, on the swan ; 2
other species.

OROBIAS, D'Eichwald.— A Nummuline
or Fusuline Foraminifer, found in the Car-
boniferous Limestone of Russia ; possibly a
true Numnmlina.

BiBL. D'Eichwald, Leih. Ross. i. 352.

ORTHOCERI'XA, D'Orb.— A Sticho-
stegian Foraminifer, related to Nodosarina ;
square or triangular in cross section; without
septal furrows ; orifice terminal, simple or
pouting.

Recent in W. Indies, O. quadrilatera (PI.
23. fig. 36) ; fossil in the Tertiary, Chalk,
Gault, and Oxford Clay.

BiBL. Carpenter, For. 166.

OR'THOCLASE. See Rocks.

ORTHODON'TIUM, Schwagr.,= 5;7/?m
pt. O. qracile, on sandstone rocks. (Wilson,
Bryol. 'Brit. 218.)

ORTHOPTERA.— An order of Insects,
containing the grasshoppers, crickets, &c.
ORTHOSI'RA, Thw. See Melosira.

0RTH0TR1CHACE.E.— A tribe of
Pottioid Mosses including several British
genera.

a. Papilla distinct, tvherexdafe, rarely obso-
lete ; peristome mostly pale, rarely orange-
coloured.

Zygodon. Calyptra dimidiate. Peristome
wanting, simple, external or internal, more
rarely glabrous, without an annulus.

Orthotrichiim. Calyptra campanulate,
plaited. Peristome absent, simple, or
double. External of thirty-two geminate
(sixteen, fig. 483) or bigeminate (eight,
fig, 537) teeth, more rarely of sixteen entire,
undivided teeth, granular, fleshy or brittle,
mostly pale, rarely orange-coloured, erect.

afterwards reflexed, arising below the mouth
of the capsule. Internal : eight or sixteen
cilia, simple, hyaline, or rarely resembling
the teeth. Vaginule ochra'ceous. In-
florescence monoecious or dioecious. Capsule
without an annulus, pyriform, grooved,
rarely glabrous; operculum capitate, conical.

b. Papillcs mostly obsolete, rarely distinct ;
peristome always coloured, purple, red, or
orange.

Glypliomitrium. Calyptra campanulate,
large, totally enclosing the capsule, deeply
laciniate, plaited. Peristome of sixteen
short, lanceolate, denselj^ trabeculate, entire
teeth, with a central line, in pairs, incurved,
arising below the orifice, orange-coloured,
smooth_ (fig. 283, p. 360). Inflorescence
monoecious.

Brachystelium. Calyptra as in the pre-
ceding, entirely or almost covering the cap-
sule, mitre-shaped, with long and repeated
laciniations, slightly plaited. Peristome as in
Trichostommn, the teeth more or less split
to the base into two arms. Inflorescence
monoecious.

Guembelia. Calvptra dimidiate, otherwise
like the following' (figs. 289-291, p. 366).

Giimmia. Calyptra mitre-shaped, laci-
niate, smooth, scarcely exceeding the oper-
culum, or shorter. Peristome simple, teeth
sixteen, lanceolate, with a median line,
trabeculate ; often, however, fissile, hence
very polymorphous, more or less split as far
as the middle into two or four teeth, or into
two arms down to the base (fig. 288, p. 365).

Fig. 536.

^ Ii

Fig. 537.

Fig. .loO. Orthotrichum pulchellum. Magn. 15 diams.
Fig. 537. Orthotrichum pallens. Fragment of peri-
stome. Magn. 50 diams.

ORTHOT'RICHUM, Hedwig.— A genus
of Orthotrichaceae (Pottioid Mosses), o-row-
ing in round tufts, fertile at the summ'it, on

OSCILLATOR lA.

[ 560 ]

OSCILLATORL\.

trees and stones, never on the eaitli. Bri-
tish species miinerous, remarkable for the
apophyses, sometimes having stomata, and
the varied character of the outer peristome,
the thirty-two teeth of which are variously
conjoined, so as to appear thirty-two, six-
teen, or eig-ht. Calyptra mostly covered
with hair-like processes (flo-. 472, p. 512).

B[BL. ^\'ilson, Bri/ol. Br. 185 ; Hooker,
Br. Fl. ii. pt. 1. 57 ; Vejitiiri, 31. M. Jn.
1881,80.

OSCILLATO'RIA, Yaiich.— A genus of
OsL-illatoriacefe (Confervoid Alga?), distin-
giiislied from the allied forms by the simple,
rigid, elastic hlaments, forming a stratum
in a common gelatinous matrix. Filaments
enclosed singly in tubular cellulose sheaths,
open at the ends, from which the fragments
emerge when broken across (PI. 8. fig. 8).
The young filaments or growing extremities
are continuous and scarcely striated ; but
by degrees transverse strife appear, some-
times very close together, sometimes dis-
tant, indicating a constriction and final
fission in the substance of the filament,
■which, when old, readily breaks at these
places. The internal structure of the fila-
ment is obscure : it seems to be composed
■wholly of protoplasmic substance, the joints
not possessing special cellulose coats; but
the substance of the filament, although
apparently solid, seems sometimes less dense
internally, since we have noticed a kind of
hour-glass contraction intermediate be-
tween the strife after the action of thick
syrup (by endosmose) and after desiccation.
The curious rounding-off" of the separated
ends of dividing filaments (PI. 8. fig. 8,
right-hand figures) seems to depend on some
power of expansion of an outer thicker layer
of the substance of the filament. The mo-
tion of the filaments ■wiU be described
under Oscillatoriaceje. The filaments
ultimately break up at the strife into di-
stinct joints, -which may be regarded as
gonklia. No formation of spores has been
observed. A remarkable and unexplained
appearance is occasionally observed at the
growing ends of the filaments : they appear
crowned by a wreath of cilia ; but these
processes are rigid and motionless.

The species occur on damp ground, on
stones, mud, in fresh water, running or
stagnant, in springs, and in brackish water ;
a few are truly marine. In the following
characters the colour of the strata is given
as seen by the naked eye, that of the fila-
ments as seen under the microscope.

In fresh -vvater, or on damp earth, &c.
a. Stratum eeruginous or blue-green.

O. limosa, Ag. Stratum dtirk green,
glossy, ■svith long rays; filaments green,
1-3300 to 1-3000" in diameter; articulations
shorter than the diameter. At the bottom
of ditches and pools.

O. tennis, Ag. Stratum dark green, thin,
with short rays ; filaments pale green,
1-4200" in diameter ; articulations equalling
or half the diameter. In muddy ditches,
&c. ; at first on the bottom, finally fluating.

O. muscorum, Ag. Stratum dark ;erugi-
nous-greeu, 3 or 4" in extent, growi)ig over
mosses in rapid streams ; filaments thickish,
pale blue-green.

- O. tiafom, Oarm. Stratum ptile verdi-
gris-green, glaucous, 1 or ly in diameter,,
resting on an ochraceous substratum ; fila-
ments hyaline, very slender. On fli.ating
sods in turf-pits.

O. (h'corf leans, Grev. Stratum smooth,
glaucous-green, membranous, peeling off" in
fiakes ; filaments pale bluish green, very
slender. Damp w'alls, pumps, &c. ; common.

b. Stratum dull green, inclining to purple,
black, or brown.

O. nigra, Vauch. Stratum blackish
green (bluish black when dry), with long
radii; filaments pale bluish green, 1-2S00
to 1-3000" in diameter ; joints equalling or
a little shorter than the diameter. Ditches
and ponds. Common.

O. autumnalis, Ag. (PI. 8. fig. 8). Stra-
tum purplish or greenish black ; filaments
pale dirty bluish green, 1-4000 to 1-5000" in
diameter; joints shorter than the diameter.
Damp ground, walls, iSrc. Common.

O. contexta, Carm. Stratum glossy black,
spreading three feet or more, appearing
satiny and striated to the naked eye; fila-
ments pale green, 1-3000" in diameter; ar-
ticulations largish. On mud ; apparently
common.

O. ochraeca^ Grev., is probably the same
as Leptothrix ochracea.

** Marine, or in brackish witter.

0. littoralis, Carm. Stratum bi-ight an'u-
ginous-green ; filaments deep green,' thicker
than in O. nigra ; joints one third the
diameter. Pools on the sea-shore. See
Symploca.

BiBL. Harvev, Br. Alg. 1st ed. 161;
Mar. Alg. 228 ; 'Phgc. Brit. pis. 105, 251 ;

OSCILLATORIACE^E. [ 561 ] OSCILLATORIACEJE.

Hassall, Ah/. 244, pis. 70-72 : Kiitz. Sp. Ahj.
237; Tab. 'P/ii/c. lid. i. pis. 38-44 ; Rabeuli.
Alff. ii. 95 ; Engelmauu, Beweg. Bot. Zeit.
1879.

OSCILLATORIA'CE.^.— A family of
Oonfervoid Algfe, containing organisms of
considerable diversity and not well cha-
racterized at present, owing to the obscurity
of the reproduction. The genus Oscillatoria,
with its nearest allies, is composed of
cylindrical filaments of protoplasmic sub-
stance, invested by a continuous cellulose
sheath or tubular cell-membrane. The in-
ternal (solid ?) filament gradually becomes
transversely striated as it increases in age,
and subsequently breaks across at the trans-
verse lines ; and the fragments readily
escape from the sheaths, since no cross walls
of cellulose are produced (PI. 8. fig. 8). These
kinds exhibit clearly the remarkable motion
from which the family takes its name. They
are mostly found upon damp ground, form-
ing wide and irregular strata. Rivuluria and
the allied genera have the joints of the fila-
ments more distinct; and the filaments are
coherent into definite fronds, on which they
stand erect or radiate from a centre (PL 8,
figs. 13, 16). The sheaths often become
complicated, from the internal multiplica-
tion and the persistence of the cellulose
sheaths of several generations one within
another (see Petaloxema), often gelati-
nously swollen up, and sometimes decomposed
into spiral fibrous sti-uctures (PI. 8. fig. 15 ;
see Spie.\i. structures). Some of the
remaining forms differ considerably from
the above, and are imperfectly imderstood.
Spindina (PL 7. fig. 15) has the filaments
curled spirally; and in the strange plant
Didymohelix (PL 1. fig. 10) two spiral fila-
ments occur twined together. These last
minute forms generally occur imbedded in a
gelatinous stratum.

The structure of the OsciUatoriacese,
judging from Oscillatoria, Microcolem, and
Lynghija, differs importantly from that
of ail other Confervoids. The filaments are
not composed of rows of cells, but, in the
earliest condition, of a cylindrical thread of
protoplasm, coloured gi-eyish, green, brown,
or purple in different cases. The ends of
the gi'owing filaments are narrower and de-
void of strife, and bave no perceptible cellu-
lose sheath ; when a little older, cross stiise
appear, consisting of double rows of granides
or dots, and the tubular cellulose coat is
evident; finally tbe strife become distinct
lines (see PL 8,' figs. 8-22). In this stage,

external violence will cause the filament to
break across at the strijB ; and the fragments
then slide along inside the cellulose sheath,
the broken ends always assuming a rounded
form like that of the free extremities (PL 8.
fig. 8 6). When these fi'figments slide quite
out of the sheaths, the latter appear as con-
tinuous tubes (PL 8. fig. 8 a), seldom with
any cross markings opposite the stria3 of the
internal mass. In Lynyhya the division
seems to take place in a peculiar manner,
accompanied by an interstitial gi-owtb com-
parable to that of Zygnema. In a well-
developed filament, every eighth stria is
strongest, the intermediate fourths rather
lighter, every second one between them
paler still, and the intermediates of these
only just marked; while in Oscillatoria the
strife seem to be gradually less definite
towards the growing apex of a filament.
The filaments appear solid as ordinarily
viewed ; but the endosmose resulting from
placing them in syrup or gum-water causes
them to contract between the strife, or to
break up into lenticidar disks. The ultimate
fate of all the filaments seems to be a sepa-
ration into disks or globular gonidia, by
bi-eaking across at the strife.

In Microcolem (PL 8. fig. 9) and many
Rivularice there would appear to be a trans-
verse multiplication like that occurring oc-
casionally in NosTOC, as the filaments' are
found lying side by side in gelatinously de-
composed outer (parent) sheaths. The fila-
ments of the Itivularice are seated on a
large basal cell (PL 8. figs. 13, 16, 18), the
nature of which is not understood.

The remarkable spontaneous motion of
many Oscillatoriaceae presents a considerable
variety of conditions. In Oscillatoria and
Microcokus the ends of the filaments emerge
fi-om their sheaths, the young extremities
being apparently devoid of this coat ; their
ends wave backwards and forwards, some-
what as the fore part of the bodies of cer-
tain caterpillars are waved when they stand
on their prolegs with the head reared up.
This motion probably depends upon the ir-
regular contraction of difierent parts of the
protoplasm. The filaments also emerge
from the tubes and break up ; and the fi'ag-
ments then exhibit an oscillating movement
like that of a balance, -together with an ad-
vance in a longitudinal direction. Lynyhya
(PL 8. fig. 10) does not appear to oscillate,
at aU events when in long filaments ; Spiru-
lina and other forms exhibit only a tremu-
lous oscillation ; Didymohelix probably ac-

2o

OSCILLATORIACE^. [ 562 ] OSCILLATORTACEvE.

quires its double-spiral character from the
eutwining of origiually distinct filameuts.
Leptothriv and the allied genera are very
imperfectly known, and are only included
here from the absence of indications of closer
affinities elsewhere ; very likely thej'- are
mycelial filameuts of Fungi.

These plants occur on damp ground,
rocks, or stones, and among Mosses and
other Confervse on rocks, stones, &c. in
fresh and salt water, and are allied in some
respects to the Nostochaceje ; but the
articulations of the filaments of the latter
are aU perfect cells with a complete cellulose
wall, multiplying by di-vision in the same
way as the Confervaceae.

8yno2)sis of British Genera.

A. Oscillatoriece. Filaments transversely
striated or moniliforai, sometimes spi-
rally curled ; sheathed, or, in the minute
forms, without evident sheaths; exhi-
biting spontaneous oscillating or creep-
ing motion. Increased by transverse
division.

Didymolielix (PL 1. fig. 10). Filaments
brown, very slender, continuous, curled spi-
rally and twisted together in pairs. No
evident sheaths, but a common investing

•ielly-

Oscillatoria (PI. 8. fig. 8). Filaments
coloured, continuous, transversely striated,
readily breaking across, with a proper cellu-
lose sheath, oscillating ; collected in strata
and imbedded in a common gelatinous
matrix.

Microcoleus (PI. 8. fig. 9). Filaments as
in Oscillatoria, but collected into bundles
in a common gelatinous dichotomously
branched tubular sheath ; filaments oscil-
lating.

Cmnocoleus. Filaments branched, annu-
lated, contained with their ramifications
within a tough, more or less permanent
sheath which bursts irregularly.

Symploca. Filaments as in Oscillaloria,
but erect and tufted, coherent at their bases,
bristling above.

B. Lymibi/ea. Filaments motionless (r),
oscillarioid, enclosed in a very distinct
sheath, tufted, or forming strata, with
or witliout an enveloping jelly.

Dasyylcea (PI. 8. fig. 11). Filaments un-
branched, sheathed; older sheaths broad,
coalescent outside into an amorphous gela-
tinous stratum.

Lynyhya (PL 8. fig. 10). Filaments elon-
gated, distinctly articulated, unbranched,
with distinct convoluted cellulose tube, but
without a gelatinous matrix (motion creep-
ing ?) ; articulations very close.

Liehleinia. Filaments short, erect, tufted,
unbranched, with distinct cellulose coat,
free, without an investing jelly.

Chamcesiphon, Crenothrix,

C. Scytonemece. Filaments distinctly arti-
culated, simple or branched, motionless,
with distinct articulations and large in-
terstitial (propagative ?) cells ; sheaths
at length softened and swollen, but with-
out a common gelatinous matrix.

Scytonema (PL 8. fig. 19). Filaments
csespitose, or more rarely fasciculate, with
a double (lamellar) gelatinous sheath,
(mostly) closed at the apex ; branches con-
tinuoiis by lateral growing out of the pri-
mary filaments, with a knee-like base.

Desmonema. Filameuts branched, more
or less coherent ; branches of two kinds, pri-
mary branches each with a connecting cell
at the base, secondary branches without
connecting cells; annulated. See Toly-

POTHRIX.

Arthronema (PL 8. fig. 20). Filaments
distinctly articulated, simple, in short
lengths, overlapping at their ends within
the gelatinous sheath.

Petalonema (PL 8. fig. 21). Filameuts
branched, with the outer sheaths of the
single joints expanded upwards and out-
wards into fumiel-shaped bodies, each partly
overlapping its successor, forming a common
obhquely laniellated and transversely barred
gelatinous cyhnder.

Calothrix (PL 8. fig. 22 ). Filaments very
closely articulated, tufted, with branches in
apposition for some distance, here and there
cohering laterally. Sheaths firm, often
darli-coloured.

Tolypothrix, Filaments free, radiantly
or fastigiately branched, most distinctly
articulated at the bases of the branches ;
branches continuously excurrent, not in ap-
position ; sheaths thin, hyaline.

Sirosip/toH. Filameuts single, double or
triple, within a distinct common sheath,
very distinctly articulated; branched by
lateral budding, the branches divergent.

Schizothrix (PL 8. fig. 17). PMament.^
branched by division ; sheaths laniellated,
thick, rigid, curled, thickened below, finally
longitudinally divided.

Syinphyosiphon. Filaments erect or as-

OSCiLLATOKIACE^.

[ r,G3 ]

OTOGLENA.

cending, enclosed inlamellated,hard sheaths,
concreted laterally at their bases, involved
in jeUv.

Rhizonema. Sheath cellular and fur-
nished throughout its leng-th with niunerous
branched and anastomosing rootlets (?).
Filaments distinctly anmdated, and inter-
rupted here and there by a comiecting cell.
Branches in pairs, arising from a protrusion
of the filament.

Fischer a,

D. Rivulariece. Filaments distinctly arti-
culated, with an enlarged basal cell,
mostly attenuated above, connected into
definite or indefinite fronds ; motionless.

Schizosi})hon (PI. 8. fig. 13). Basal cells
globose, filaments simple, distinctly articu-
lated, mostly attenuated towards the apex,
sheathed, sheaths connate into groups, hard,
dark-coloured, open and expanded above,
and overlapping so as to form a succession
of ochre^e which have the free borders
slit up into filaments or fringes ; also dis-
pla^dng a spii'al fibrous structm'e in dissolu-
tion.

Physactis. Filaments whip-shaped, toru-
lose at the base, sheathed, sheaths simple,
gelatinous, collected into a globose and
solid, or subsequently a buUose-vesicu-
lar frond ; in the globose fronds the fila-
ments radiate from the centre, in the vesi-
cular fronds from the internal or lower
surface of the gelatinous matrix,

Amactis (PI. 8. fig. 15), Filaments
branched, jointed, with thin sheaths, col-
lected into a sohd pulvinate frond, concen-
trically zoned by the dichotomous branching
of the filaments. Sheaths more or less
solidified by carbonate of hme ; sometimes
exhibiting a spiral structure in dissolution.

Rwulana (PI. 8. fig. 18). Filaments
with an oval basal cell succeeded by one of
cylindrical form {manubrium), the remainder
short, attenuated in diameter upwards (whip-
shaped) ; sheaths sometimes saccate below,
open (not fringed) above ; forming a slippery
gelatinous frond.

Euactis (PI. 8. fig. 16). Filaments whip-
shaped, with repeated ochreate sheaths,
forming fronds in which they radiate, and by
superposition of successive generations form
concentric layers ; sheaths cartilaginous,
lamellated, fii-mly united laterally, dilated
upwards (funnel-shaped), decomposed into
& fiinge at the orifice.

Inomeria. Filaments whip-shaped, ver-
tical, parallel ; sheaths obscure, everywhere

decomposed into very slender filaments ;
forming crustaceous fronds, becoming stony.
Petronema, Densely ctespitose, erect,
somewhat regularly branched; branches free,
with obtuse rounded apices, and each with
a connecting cell at the base. Filaments
annulated and growing thicker upwards.

E, Leptotrichece. Doubtful Oscillatoriacese.

Leptothrix. Filaments very slender,
neither branched, articulated, concreted,
nor sheathed.

Ihjpheothrix, Filaments unbranched, in-
articulate, sheathed, interwoven into a more
or less compact stratum.

Symploca. Filaments unbranched, inar-
ticulate, sheathed, concreted into branches,
conjoined at their bases; sheath a simple
hyaline membrane.

OSMIC ACID.— An oxide of the metal
osmium, obtained from platinum-ores. It
is a crystalhne, volatile, poisonous substance,
soluble in water, with a powerfully irritating
odoui". Its aqueous solution is used for
hardening and colouring certain animal tis-
sues black or dark blue, as fat-ceUs and
globides, the medulla of nerves, more slowly
the gaughon-cells, the connective-tissue cor-
puscles, Zoophytes, &c. The ordinary
strength is about 90 grains to a pint.
Small pieces of the structures should be
immersed in it, fi-om \ hour to 24 hours,
then weU-washed in distilled water, and
mounted in acetate of potash or Farrant's
compound. It is also useful for its remark-
able power of killing Infusoria, Rotatoria, &c.
so suddenly, that the cilia remain extended,
instead of being retracted and imdistinguish-
able as with other reagents. (Ranvier, Hist.
techn. ; Robin, Micr. 220 ; Frey, Mikr.)

OSMO'SIS. See Endosmose.

OSMUN'DA, Linn.— A genus of Osmun-
daceous Ferns, represented in Britain by
Os7nunda regalis (tigs. 222, 223, p. 319), the
Royal or Flowering Fern, as it is termed, a
large and handsome plant, found in damp
situations : not common.

OSMUNDA'CEyE,— An order of Poly-
podiaceous Ferns, characterized by the broad
imperfect annulus on the back of the spo-
ranges. Genera :

Osmunda. Sporangia on metamorphosed
pinnules.

Todea, Sporangia on imchanged pin-
nules.

OSTRACO'DA. See Entomosthaca.

OTOGLE'NA, Eln-.- A genus of Rota-
toria, of the familv Hvdatintea.

2o 2

OTOLITHS,

[ 5G4 ]

OVARY.

Char, Eyes three ; one sessile and cervi-
cal, the two others stalked and i'routal;
neither jaws nor teeth present.

O. papulosa. Body campanulate, turgid,
rough with papillas; freshwater; length
1-U6".

BiBL. Ehr.//^/. 4.53; Pritchard, Inf. 690.

O'TOLITHS.— The crystalline or crys-
talloid particles found in the lab^Tinth of
the internal ear. They are enclosed in sacs,
appearing as white specks ; and are com-
posed of carbonate of lime, with an organic
basis, which is left after the action of dilute

OTONYS'SUS, Kol.— A genus of Sar-
coptidie (Anoplura). O.sfkholasius, on the
bat ; other species. (Maddox, M. Mic. Jn.
1871, 144; Murray, Ec. Ent. 317.)

OTOS'TOMA, Carter.— A genus of Holo-
trichous Lifusoria.

Char. Ovoid, mouth ear-shaped; anus
terminal ; nucleus long ; contractile vesicles
double. Its cysts have been discovered on
Nitella, and give exit to monadiform beings
approaching the parent shape.

O. Carteri, Bombay.

BiBL. Carter, Ann. N. II. 1866, xvii. 117;
Kent, Inf. 500.

OVA OF Animals. — The germs secreted
by the ovaries. When extruded from the
body, they are generally termed eggs (Eggs).
See OvTJM,

OVARY. — The organ in which the ova
or germs of the future offspring are formed
and temporarily contained.

The ovary consists of an outer fibrous
capsule, and a parenchyma or stroma.

Fig. 538.

Transverse section ol a human ovary at the fifth
month of xiregnancy. n. Graafian vesicle of the under,
h, of the upper surface; c, peritoneum; rf, tlie tunica
albuginea; in the centre are two corpora lutea; e,
stroma of the ovary.

The outer coat, or tunica albuginea, is
firm, white, and intimately connected with

the subjacent sti'oma: it consists of inter-
lacing bundles of connective tissue with
few elagtic fibres.

A layer of columnar or germ-eijithelium
covers the capsule, therefore different from
that of the peritoneum, with which it is
continuous at the base of the organ. The
germ-epithelium here and there lines tube-
like inward prolongations (the ovarian
tubes).

The stroma (fig. 538 e) is composed of
nucleated connective tissue, and in it are
imbedded the Graafian vesicles (fig. 538 a).
They vary greatly in number and size ; the
largest are generally nearest the surface, and
project more or less, so as to give it a nodu-
lar aspect. They are round closed sacs
(fig. 539). Each possesses two coats ; the

Fig. 539.

Graafian vesicle of the pig. a, outer, b, inner layer
of the fibroua coat; c, membrana granulosa; d, liquid
contained in the vesicle ; e, proligerous disk ; f, ovum
with the zona pellucida, yolk, and germinal vesicle.

Magnified 10 diameters.

outer is a fibrous and vascular layer, con-
nected with the stroma by somewhat lax
areolar tissne, which consists of two layers :
the outer composed of ordinary fibrous con-
nective tissue; the inner consisting of young
connective tissue, rich in cells, usually fusi-
form, stellate, or spheroidal, and resembling
amoeboid cells. Lining this is the epithe-
lium of the follicle, which covers the whole
of the inside of the tunica propria, and
forms the membrana r/ranulosa (fig. 539 c).
Next the siu'face of the ovary this is
thickened and projects inwards, forming the
proligerous disk, e ; the epithelium is strati-
fied and columnar. The ovum is imbedded
in this proligerous disk.

The cavity of the Cjraafian vesicle con-
tains a hquid resembling the serum of tlie
blood ; and in it are found gi-anules, nuclei,
and cells, arising from the disintegration or
the membrana granulosa.

When the vesicle bursts, the ovtim es-

VIPOSITOR.

[ 565 ]

OVULE.

capos surrounded by the cells of the proli-
gerous dit^k and the adjacent part of the
epithelium ; the inner surface then becomes
wrinkled, and gives oft" fleshy processes
which become yellowish, and form the cor-
pora lutea.

In those animals in which the amount of
stroma present is small in proportion to the
size of the vesicles, the ovaries have a race-
mose appearance.

In many of the lower animals the ovaries
are tubular, the ova lying closely packed
within them.

BiBL. Kblliker, Mik. An. ii. ; Siebold,
Vei-ffl. An. ; Todd's Cyclop. An. ; Waldeyer,
Strieker's Hist. ; Balfour, Covtp. Embnjol.
1880.

OVIPOS'ITOR. See Insects, p. 433.

OVULE or OV'ULUM.— The name ap-
plied to the rudiment of the seed of Flower-
ing Plants, produced in the ovary or ger-
meu during the development of the flower,
fertilized by the pollen-grains when com-
plete ; and afterwards converted into a Seed
Dv the development of the Embryo and
other secondary structures during the con-
version of the ovary into the fruit. For the
general conditions of the ovules in ovaries,
reference must be made to botanical worlcs.
The ovules make their appearance upon the
placenta as cellular papillfe rising up from
its surface, and are at first simple ; this first
development, the main feature of the organ,
is called the ?mcleiis (figs. 540-642). In

Fig. 540.

Fig. 541.

Atropous ovules.

Fig. 640. Tonng ovule of Chelidonium. n, nucleus ;

ch, chalaza.
Fig. 541. Toung ovule of mistletoe, consisting of a

nucleus only.

rare cases this remains naked ; but in most
instances one or two coats are produced,
arising as circular folds near the base, and
gi'adually gi-owing up over the nucleus
(fig. 542), leaving only a small hole or pas-
sage at the apex, leading down to the point
of the nucleus. When two coats are
formed (fig. 54.3), the inner appears first;
the outer originates later and grows up over

tlio inner, and it is generally thicker and
more developed. The inner is the secundine
of Mii'bel, the outer the prijnine (figs. 543,
544, 547, S, P). German writers reverse

Fig. 542.

Fig. 543.

End

-P

Atropous ovules.

Fig. 542. Young ovule of walnut, consisting of a nucleus

iV, with a single coat A' ; End, the endostome

or micropyle.
Fig. 543. Young ovule of Polygonum. F, funiculus;

P. primine (of Mirbel); S, secundine; Ex,

exostome ; End, endostome.

Magnified 40 diameters.

these names, resting on the true order of
development. Some term them the integu-
menUivi, intermim and externmn. The inner
is the tegmen, the outer the iesta of Brown.
The passage at the apex, leading to the nu-
cleus, is called the microjn/le ; sometimes the
orifice in the outer coat is distinguished
from that in the inner coat, and they are
termed respectively exostome and endostome
(fig. 547). While the nucleus and coata
are becoming perfected, one of the cells
situated near the apex of the nucleus takes

Fig. 544.

Fig. 545.

..yr«

A.e

Sections of atropous ovale of Polygonum.
P, primine ; S, secundine; N, nucleus ; SE, embryo-
sac; F.e, P/, nascent embryo.

Magnified 20 diameters.

on a peculiar character, becoming more de-
veloped than the rest, and often causing the
absorption of part, or sometimes the whole,
of the tissue of the nucleus ; it appears at
length as a large sac eccupying the centre of
the ovule ; this is the embryo-sac (fig. 544).
The base of the ovule is pushed up from
the surface of the placenta during its deve-
lopment so as to appear at length sup-
ported on a stalk of variable length ; this is

OVUI.E.

[ 566 ]

O^njLE.

termed the funiculus (figs. 543 F, Ml f) ;
the point of attachment of this stalk to the
body of the ovule (marked by a scar when
the ripe seed separates) is called the hihnn.
That region of the interior where the lower
parts of the coat are confluent with the
base of the nucleus, is called the chalaza
(fig. 546 C). ^, ^ ^

The form of ovules is much aflected by
excessive development of their constituent
parts in special dii-ections before the fertili-

Fig. 546.

Section of campylotropous ovule of the wallflower.

C, chalaza ; N, nucleus ; S, inner coat ; P, outer coat.

Magnified 20 diameters.

zation. If all parts grow equally, the com-
plete ovule is erect on the placenta, with its
hilum and also the chalaza turned towards
the latter, and its micropyle at the opposite
free end : such an ovule is technically termed
atropous or oi-thotropotis (figs. 5'41— 545).
Very frequently an excessive gi-owth takes
place at one side of the coats of the ovule,
so that the chalaza is carried up and di-
rected away from the placenta, the micro-
pyle being at the same time turned down
towards the latter ; but as the growth is in
the coats of the ovule, the hilum remains at
the base, near where the micropyle arrives ;
such an ovule is termed anatropous (fig. 116,
p. 157). The hilum is then connected with
the chalaza by a ridge (a kind of adherent
funiculus) called the raphe. In other cases
the form becomes altered by the point of
the ovule turning down, the entire structure
becoming folded or bent upon itself, with-
out disturbance of the relative positions of
the hilum and chalaza, while the micropyle
is brought down, as in the anatropous
ovule, to the vicinity of the hilum. Thi.s
form is termed camptjlotropous (fig. 546).
Other conditions occm* less frequently,
among which is the amphitroiwus form
(figs. 550 & 551).

During these developments the embryo-
sac also undergoes various changes. Some-
times, as in the Orchidaceae, it expands so

as to obliterate all the tissue of the nucleus,
and appears like a simple sac enclosed by

Fig. 648.

Fig. 549.

Magnified 40 diameters.

Fig. 550.

Fig. 551.

Magnified 20 diameters.
AmEhitropous ovule of mallow in difi"erent stages.
Fig. 551. Section,

the coats ; in. the Scrophulariacese and other
orders it produces peculiar lobes or pouches
at various points; in the Santalacea3 itgi-ows
out from the summit of the nucleus as a
free, naked, tubular process, kc.

Tip to this point the ditferences in ovules
are such as may be termed secondary ; but
a primary distinction now comes into view,
connected also with a difference in the ex-
ternal conditions, affording grounds for the
division of the Flowering Plants into two
great classes. In the Couiferte and Cyca-
dacese the ovules are developed upon open
carpels, and consequently the micropyle
may receive the pollen-grains immediately,
when expelled from the anthers. Plants
exhibiting this condition ai'e termed Gym-
NOSPERMS, or naked-seeded. In the Dico-
tyledons and Monocotyledons the carpels
are always closed up into cases or ovaries,
surmounted by a stigma, sessile or elevated

OVULE,

[ 5(37 ]

OVULE.

upon a style, and the pollen, falling- upon
the stigma, produces there its pollen-tubes,
which pass down through what is called
the couducting tissue of the style and upper
part of the ovary, on to the placentae,
whence they make their way to the micro-
pyles of the ovules. Plants exhibiting
these conditions are distinguished as Angi-
osPERMs or covered-seeded.

The next phenomena which characterize
the development of the ovules of the An-
giosperms may be briefly given as follows.
The formation of the embryo-sac has already
been described. Shortly before the opening
of the flower, in most cases, this sac is more
or less denselj' filled with granular proto-
plasm, in which a variable number of nuclei
may be seen (PI. 47. figs. 1-7). About the
time when the pollen-grains are discharged
fi'oni the anthers, a number of minute, free,
globidar protoplasmic bodies may be dis-
covered in the embryo-sac, usually three
(^more rarely one) of these being crowded
into the upper end of the embryo-sac and
constituting what are called the germinal
bodies or masses (PI. 47. fig. 4), Others,
which often occur in the embryo-sac, are
generally collected near the bottom of it;
they are apparently characteristic of par-
ticular famih.es only; in some plants they
are very large, as in the Crocus. About
this time the embryo-sac often exhibits
asymmetrical growth, forming pouches or
processes, sometimes at the summit, some-
times at the base.

"When the pollen-grains fall upon the
stigma, they protrude their pollen-tubes
(see PoLLEx), which pass down through
the conducting tissue, and enter the micro-
pyles of the ovides. Wben they reach the
apex of the embryo-sac, they either stop,
often swelling a little, or they pass down a
short way over its side (PL 47. tig. 5) ; very
rarely two pollen-tubes are found engaged
in the micropyle of the same ovule. It is
not absolutely known whether the cavities
of the pollen-tube and the embryo-sac
become actually continuous by absoi-ption
of the walls at the point of attachment ; it
is generally believed not, but we feel some i
doubt on this point. The essential point of
the process is the intermixture of the con- '
tents of the pollen-tube ^\4th the substance j
of the germinal body. In the higher [
Cryptogamia and in the Algae, the impreg- |
nation is of a similar nature ; but there the
germ-masses are fertilized by the agency of ;
spermatozoids, which make their way to 1

them, cither constituting or carrying the
impregnating matter, Avhich in the case of
the pollen-tube is a liquid, containing fine
granules, but exhibiting no trace of active
spermatic bodies, except that refractive gra-
nules are sometimes seen in active motion
in the end of the pollen-tube.

Soon after the pollen-tube has reached
the point of the embryo-sac, one (rarely
two, giving rise to Polyembryony) of the
germinal bodies becomes invested by a cel-
lulose membrane {(/erm-cell), and usually
changes from a spherical to an oval form, a
transverse septum soon dividing it into two.
Most frequently the elongation continues,
with a successive formation of septa, until
the nascent embryo appears as a rounded or
oval cellule suspended at the base of a
simple confervoid filament (suspensor) ; in
other cases the formation of the first trans-
verse septum is followed by the expansion
into two globular cellules connected by a
naiTow neck, the upper, almost devoid of
contents, constituting the suspensor (Pota-
moffefon, Zannichellia) ; in Orchis, the upper
of the first two cells grows upwards and
outwards, as a blind septate confervoid fila-
ment, through and beyond the micropyle of
the ovule. In Tropceolum and Zea the sus-
pensor becomes more complex, by formation
of perpendicular septa. In all cases the
end or embryonal cell, at the point of the
suspensor, which always appears densely
filled with protoplasm, ultimately enlarges,
and by segmentation is converted into the
embryo (PI. 47. fig. 6).

During the early development of the em-
bryo, the embryo-sac is often found more
or less densely filled with free cells formed
from its protoplasm (ewf?os^?^;-m-cells) . These
are fi-equently absorbed, and disappear du-
ring the growth of the embryo, this ulti-
mately filling the embryo-sac ; while in
other cases they persist and multiply, form-
ing the ALBUMEN of the seed. In the
Nymphaeaceae these cells remain, forming
an inner Endosperm or Albumen, in addi-
tion to that formed from the body of the
nucleus. In other cases (those of exalbu-
minous seeds) the embryo not only displaces
these internal endosperm-cells, but in the
course of its growth causes the absorption
of the tissue of the nucleus, and idtimately
constitutes the entire seed, enclosed only
by the true integuments. The remaining
characters are given under Albumen and
Embryo,
Tulasne is in doubt whether the germinal

OVULE.

[ 668 ]

OVULE.

vesicles exist before the pollen-tube enters
tlie micropyle. We have certainly seen
them before ; but we believe they do not
possess a cellular coat before impregnation.
Observations on the ovule of Santalum
album have led us to conclude that they
receive the influence of the pollen -^hile in
the state of nucleated protoplasmic cor-
puscles, analogous to the unimpregnated
spores of Fucus; and this view has since
been supported by the later observations of
Schacht, although Hofmeister and Radlko-
fer maintain that the germinal bodies possess
a cell-membrane before impregnation.

Li the Gymnospermous Flowering Plants
(Couiferse, &c.) the ovule, consisting of a
cellular nucleus and a single coat, is placed
upon an open carpel, and its widely-open
micropyle receives the pollen-grain. At
the period of impregnation, the embryo-sac
is a cavity deeply seated in the tissue of
the nucleus ; it is formed by the coalescence
and expansion of several cells (in the Yew
there are often at first three embryo-sacs).
In the embryo-sac a number of free nuclei
soon appear, and numerous free (endo-
sperm-) cells are formed. In many of the
Abietinese this goes on imtil the spring
following the impregnation. Ultimately
the embryo-sac is found to have increased
to more than twenty times its original size,
with the endosperm-cells applied in layers
over the inside of its walls, increasing in
number until the cavity is filled up. Then
a certain number of cells (from three to
eight in different genera), situated near the
micropyle end, but each in the layer next
but one to the wall of the embryo- sac,
become enlarged, and the cells intervening
between these enlarged ones (secondary
embryo-sacs) and the wall of the original
embryo-sac become divided, by two per-
pendicular septa standing at right angles,
into four cells. A central intercellular pas-
sage then appears at the contiguous angles
of these four cells. These new bodies, which
closely resemble the archegonia of the Lv-
copoioiACE^, were called corpuscula by
Brown, who discovered them.

Free cells, or perhaps merely protoplasmic
masses, are next formed in the secondary
embryo-sacs of the corpuscula, several at
the upper, oiie at the lower end. The pol-
len-tubes now advance, breaking down the
tissue of the nucleus, until their points
reach the corpuscula ; and one then makes
its way down the intercellular canal of
each, to reach its secondary embryo-sac ;

the free cell at the base of this (germinal
vesicle) then becomes divided into four col-
lateral cells ; these multiply again ; and sub-
sequently the cellular body (jiroembri/o) so
formed breaks through the base of the
secondary embryo-sac, and grows down in
the substance of the lower part of the nu-
cleus, which is now in a state of semisolu-
tion. The proembryo then separates into
four cords, corresponding to its four primary
cells ; and these filaments (suspensors) ter-
minate iu rounded cells, each of which is
an embryonal cell; so that there are now
four times as many rudimentary embryos
as there are corpuscula. Out of all these,
only one ultimately remains and becomes
perfectly developed ; the rest are absorbed
during the ripening of the seed. In the
latter, the perfect embryo is found Ipng in
a mass of alljumen formed of the nucleus ;
its radicle, developed at the point of junc-
tion of the suspensor, never becomes very
clearly defined at its extremity, but remains
organically continuous with the albumen.

Other points relating to the development
of ovules will be found under Polyeji-
BRYONY, Seeds, and CELL-formation.

The methods of investigating the deve-
lopment of ovules are simple in their nature,
but rather difficult in practice. The ordinary
plan is to place an ovule between the thumb
and fore finger of the left hand, and with a
\tiry sharp lancet cut it into two unequal
pieces, in the direction of the axis. The
larger of the two being then laid on its flat
side on the finger (by the aid of a mounted
needle), another slice is made so as to leave
a section preserving all the central part of
the ovule. This adheres either to the finger
or the lancet ; and a di'op of water should be
placed on it to free it ; then it may be trans-
ferred to a slide with a very fine cainel's-
hair pencil. Examined under a low power
(a half-inch), it will probably be found to
require further dissection, with exceedingly
fine needles, under a simple lens: some-
times mere pressure is of service. For the
minute details, the quarter and eighth ob-
ject-glasses will require to be applied. We
have found ovules which have been kept in
spirit easier to dissect ; when fresh, the cell-
membranes are excessively delicate. It need
scarcely be added that ovules require to be
examined in all stages in order to imder-
stand their developmental characters; and
the student must not be disheartened by the
failure of a large proportion of his sections
to ali'ord satisftictorv observations.

OVULITES.

[ 509 ]

OVUM.

BiBL. Brown, Ajyp. to King's Voyage,
1820; Linn. Tr. 1833; Mirbel and Sparh,
Ann. Sc. Nat. 2 s6r. xx. 257 ; Mohl, Bof.
Zeit. 1847, 1855; Miiller, ibid. 1847;
Sclileiden, Nova Acta, xix. 29; Ormuh.
Bot. ; Hofmcister, Entsteh. d. Emhnjo,
1849; Unters. hoher. Crypt. 1851; Ahh.
K. siichs. Ges. vi. ; Planstein, Flora, 1857 ;
Tulasue, Aim. Sc. Nat. 3. xii. 21, 4. iv. 65 ;
Schaclit, Beitr. z. An. u. Phys. 1854 ;
Jahrh. loiss. Bot. i. 1857 ; Bot. Zeit. 1858 ;
Criiger, Bot. Zeit. 1851, 1856; Eadlkofer,
Entsteh. des Embryo, 1856; Henfi-ey, Linn.
Tr. xxi. 7, xxii. 69 ; Tr. Brit. Asxoc. 1856 ;
Bentley, Man. Bof.; Henfrey-Masters, i?oi^. ;
Cbalin, Ann. Sc. N. xix. 1874, 1 ; Sachs, Bot.
558; Stvasshm-gev, Zellcnbiidung, 1880.

OYULI'TES, Lamarck {Oveolites) .—A
large elegant one-celled ForaLuiuifer, re-
garded by some as a calcareous Alga ; either
ovoid, sausage-shaped, or like a drumstick ;
shell porous, with large terminal apertures ;
length 1-25" and more.

Fossil ; abimdant in the Eocene of Grig-
non, Hauteville, &c., France; rare in the
Miocene of San Domingo.

BiBL. Parker & Jones, Ann. N. H. 3. v.
292, and 1877, xx. 77.

OVUM OF Animals. — Several points in
regard to the structure of the ovum, and
the nature of the changes which it imder-
goes at different periods of its development,
are in doubt and obscurit3^

The first perceptible trace of the ovum
existing within the ovary is formed by a
very minute gi-anule or globule, not sur-
roimded by a cell-wall. This gradually
enlarges; and when it has attained a certain
size, being still very minute, a smaller sphe-
rical globule forms in its interior. The
minute internal globule is th.Q germinal spot;
and the external globule is the germinal
vesicle. It appears, however, that in some
cases the germinal spot is formed fu-st, and
the germinal vesicle subsequently. When
these have still further grown, a cell-waU
separated by a slight interspace forms
around the germinal vesicle ; and this inter-
space contains a transparent liquid. Minute
granules then arise in the liquid, which
becomes inspissated ; and subsequently a
number of globules of sarcode — yoJk-
glohides — become perceptible in it ; this
mass forms the yolk ; and the surrounding
membrane is the vitelline membrane. As
the ovum attains further development, al-
buminous layers are deposited upon and
fused with the vitelline membrane, fonning

the zona pellucida or chorion (fig. 562 a),
Fig. 552.

Human ovum from a Graafian vesicle of moderate
size, a, zona pellucida; ft, vitelline membrane and
outer boundary of the yolk ; c, germinal vesicle with
the germinal spot.

Magnified 250 diameters.

which appears as a white ring. The yolk-
globules are sometimes transparent, or
slightly granular; at others they contain
one or several vacuoles, and are frequently
aggregated into little groups. The yolk,
as it approaches maturity, frequently be-
comes coloured. It is usually whitish or
pale yellow in the Mammalia, Reptiles, and
Fishes, bright yellow or reddish in many
Birds, and often green, blue, violet, or red
in the Invertebrata. In the yolk of the
ova of reptiles and fishes, crystalline plates
are met with, consisting of an albuminous
substance, allied to Htematoidine.

Viewing the ovum as a simple cell, the
germinal spot represents the nucleolus, the
germinal vesicle the nucleus, the vitelline
membrane or zona pellucida the ceU-wall,
and the yolk the cell-contents.

Some authors consider that the vitelline
membrane is formed after the chorion.

The ovum of man and the mammalia
differs from that of the lower animals in its
remarkably small size, which depends upon
the extremely small quantity of yolk enter-
ing into its composition. The mature ovum
of man and mammalia averages about 1-200
to 1-150" in diameter, being rarely 1-100".
Another peculiarity consists in their ova,
instead of being in immediate contact by
means of their chorion or outer envelope
with the stroma of the ovary, or loose
within the cavity of the latter, as in other
animals, being enclosed in distinct larger
cells — the Graafian vesicles.

On the escape of the ovum from the ovary,
the phenomena whieh ensue vary according
to whether the ovum has been impregnated
or not. In both cases the germinal vesicle
and spot disappear ; an interspace, filled
with albuminous liquid, occurs between the
yolk and the zona pellucida ; the ovum

OVUM.

[ •'^ro ]

ovmi.

becomes coA^ered with cilia, and undergoes
a regular motion of rotation ; and certain
movements and changes in form of the
yolk-substance, which forms Amoeba-like
processes, have been noticed. In the un-
impregnated o\um, decay and decomposi-
tion subsequently take place.

Tlie essential part of the process of im-
preg-nation consists in the penetration of
the yolk by the spermatozoa, and their
subsequent solution in it. This takes place
either through tlie micropyles or the radiate
canals, or directly into the naked yolk.

In the impreg-uated ovum, the germinal
vesicle soon disappears, the chorion becomes
thinner, the ovum grows, and the yolk be-
gins to undergo segmentation ; but just
before this process commences, one or two
globules separate from the substance of the
yolk, being apparently pressed out of it,
and occupy the interspace between the yolk
and the chorion ; these globules subse-
quently dissolve in the liquid.

In the process of segmentation, at first a
notch or sUght indentation appears on some
part of the surface of the yolk; this be-
comes deeper and deeper, so as to encircle
the yolk with an annular depression. Soon
after the commencement of this, a clear
spot appears in the centre of each circum-
scribed portion of the yolk. The depression
becoming deeper, the yolk is divided into
two distinct portions. The process is con-
tinued in the case of each of these in
exactly the same manner, and in that of
the segments arising from their subdivision
also, each simultaneously acquiring a clear
spot, miiil the yolk appears entirely com-
posed of innumerable small bodies having
the appearance of nucleated cells. Finally
these become very minute, and the yolk
acquires much the appearance it had before
impregnation. Cells then form in the yolk,
as in an ordinary blastema, from without
inwards, and froni the spot originally occu-
pied by the germinal vesicle as a centre ;
and from these the tissues of the embryo
are formed.

According to this description, the seg-
mentation is not a process of cell-division
or endogenous cell-formation, and the nu-
clear spots would correspond to portions of
the yolk substance from which the granules
and globules of sarcode were absent. Com-
pare p. 140.

In unimpregnated ova, segmentation takes
place to a certain extent, but irregailarly and
incompletely.

In the impregnated ova of some animals,
as in certain of the Batrachia, most fishes
and Cephalopods, the segmentation is only
partial, a portion of the yolk remaining as
at first.

In some of the Mammalia, the zona pel-
lucida is traversed by very fine radiating
lines (canals), which are best seen in ova
immersed in water.

In the lower Vertebrate animals, the ova
are- often covered by new layers, secreted
by the ovaries, as in the Batrachia (frog,
&c.), where a thick gelatinous coat is pre-
sent. In the osseous Fishes, the vitelline
membrane is fi'equently elegantly sculp-
tured, and finely and closely punctate from
the existence of minute canals traversing
its substance. A second coat is also pre-
sent, and sometimes a third or albuminous
layer. In many of the Cyprinoidea, this
layer is represented by small radiate cylin-
ders. In several Fishes, as is so general
amongst the Invertebrata, especially Insects
(Eggs), the vitelline membrane or chorion
exhibits a facetted or sculptured appearance,
derived from the impression of the epithe-
lium lining the ovarian passages.

In addition to the fine canals traversing
the membranes of the ovum, one or more
large canals or apertures are frequently met
with resembling the micropyles of vegetable
ovules, and receiving the same names; these
are most distinct in the ova of fishes and
insects.

The study of ova and their changes is
very difficult. The most favourable objects
for the purpose exist perhaps in those of the
aquatic MoUusca ; the ova of insects, as the
large species of Musca, of species of Pule.r,
&c. are also easily accessible. Some im-
portant results have been obtained with the
ova of the frog (frog's spawn) .

BiBL. Kolliker, iMik. An. ii. ; Thomson,
Cyel. An. art. Ovum ; Newport, P/tiL Tr.
1851 and 1853 ; Siebold, Veryl. An. ; Meiss-
ner, Sieb. 4" Kollik. Zeitsch. vii. 208, 272 ;
Leuckart, Midi. Archiv, 1855 ; Claparede,
Bibl. Univ. Geneve, 1855 ; Ann. N. H.
1856, xvii. ; Bischoff, Sieh. ^^- Kiill. Zeit. vi.
377 ; Radlkofer, Befnuhtnnqs. 1857 ; Bene-
den & Bessels, M. M. J. 1869, 41 ; Kupfifer,
M. Mic. Jn. 1869, 47 ; Kowalevski, Mem.
St. Petersh. xvi. 1871 ; Klein, M. M. J. vii.
1872, 193 ; Beale, Ti: Mic Soc. 1867; Ho^o
(§•0.307; Beneden, /'ffi//", 1870; Dalliuger
& Drysdale, M. M. Jn. 'xviii. 86; Schafer,
Pr. Roy. Soc. no. 168 ; Kolliker, Entwickel. ;
Balfour, Comp. Emhryol. ; M. Baker, Phys.

OVUM.

[ 571 ]

PACHYGNATHUS.

1880; His, Mensckl.Emhri/0,1880; Reichert,
Menschl. Frucht. 1873 ; Girdwoyn, Mai. d.
(Eufs (tish), 1880.

OVUINI OF Plants. See Ovule.

OXALATES. See the bases.

OXYR'RHIS, Duj.— A genus of Flagel-
late Infusoria, belonging to the family
Thecamonadina.

Char. Body ovoid - oblong, rugose, ob-
liquely notched in front and prolonged into
a point ; several flagelliform filaments (two,
Kent) arising laterally from the bottom of
the notch.

O. marina (PI. 31. fig. 54). Body colour-
less, subcylindrical, rounded behind ; ma-
line ; length 1-500".

BiBL. Dujard.7«/.347; Pritchard, Inf. 513.

OXYT'IMCHA, Bory, Ehr.— A genus of
Hypotrichous Infusoria", of the family Oxy-
trichina.

Char. Closely resembling Stylonychia \
but the front of the bodv not produced.

O. penioneUa, E. (PI. 31. fig. 52). Body

whitish, smooth, slightly depressed, equally
rounded at the ends, often somewhat broader
in the middle ; head not distinct ; mouth
ciliated; tail with bristles. Freshwater;
length 1-720 to 1-280".

0. ffibba E. (PI. 31. fig. 53). Body white,
lanceolate, obtuse at each end, ventricose
in the middle ; ventral surface flat, with a
double row of setge ; mouth large, rounded.
Freshwater; length 1-240". Other species.

According to Haime, Oxytricha is the
larva of Aspidisca.

BiBL. Ehr. hif. 363; Duj. Inf. 416;
Haime, Ann. Sc. Nat. 3. xix. 109 ; Clap, et
Lachm. Maudes, 139 ; Kent, Inf. 786.

OXYTRICHI'NA.— A family of Hypo-
trichous Infusoria.

Char. Carapace absent; body depressed,
with vibratile cilia, setae, or cii-ri, and non-
vibratile styles or hooks. Movement crawl-
ing. Alimentary orifices two, neither ter-
minal.

Genera : —

(

Marginal cirri .

{The anterior part of the body not pro-
longed as a neck, furnished with cirri OTytricha.
The anterior part of the body neck- like,
and covered with cirri S/ichochieta.

(.Foot-cirri not arranged in rows Stylonychia.

{TTx-iu e ,, r Foot-hooks / No dorsal bristles Euplotes.

Withtrontal I ^^^^ 1 Dorsal bristles Schizopus.

ciT" LNo foot-hooks Cumpylopus.

Without frontal cirri Aspidisca.

-I

BiBL. Ehr. Inf. 362 ; Pritch. Inf. 639 ;
Clap, et Lachm, Etudes, 168.

OXYUR'IS, Rud. See Ascaris.

OY'STER {Ostrea).—k. genus of Lamel-
libranchiate Mollusca.

The giUs of O. edulis, the common oyster,
show the ciliary movement ; but it is not so
easily seen in this as in the marine mussel.

The sheUs of the fry or 'embryo oysters'
exhibit the black cross and an imperfect
set of coloui'ed rings with polarized light.

PACHNOC'YBE, Berk.— A genus of
Isariacei (Hyphomycetous Fungi), some-
what confused by authors with Doratomyces,
Corda, and Periconia, Xees. These plants
have an erect filiform stem, composed of
conjoined filaments, capitulate above, the
head being pruinose (not floccident), with
crowded simple spores. The pedicels are
mostly brownish or blackish, the spores
light-coloured ; the entire plants from 1-24
to 1-6" high. Several species occur on
rotten wood, stems, &c,

BiBL. Berk. Hook. Br. Fl. ii. pt. 2. 333 ;

Ann. N. H. 2. v. 465 ; Fries, Sum. Veg.
467,

PACHYG'NATHUS, Duges.— A genus
of Trombidina (Acarina) .

Char. Palpi conical, last joint scarcely
forming a claw; mandibles stout, chelate;
body entire, naiTowed in front ; coxfe dis-
tant ; legs gxessorial, sixth joint very long,
seventli very short; anterior legs longest
and stoutest,

P. vehitinus (PI, 6. fig. 34), the only spe-
cies. Foimd in autumn, imder damp stones.
Hairs covering the body short, fiat, and
curved, giving it a velvety aspect. Body
infiated, narrowed in front, the narrowed
portion with two projecting brownish eyes.
Insertions of the legs in two groups, not
far distant, or from the median line ; second
pair of legs shortest ; in all the sixth joint
very long, the seventh very short and nar-
row (6), as in Tetranychus, Megamerus, and
Paphignathus ; claws two, large ; rostrum
projecting; palpi (a) short, about twice the
length of the labium ; mandibles very large
and stout at the base. Movement slow,

BiBL. Duges, Ann. Sc. Nat. 2, ii. 54;
Gervais, Walck, Apter. iii. 171.

PACHYMA.

[ -^72 ]

PABINA.

PACHY'MA, Fr. — A supposed genus
of Sclerotiacei, but probably a condition of
certain roots, the substance being converted
into pectic acid. It is well known in the
United States imder the name of Tucha-
hoo.

BiBL. Fr. Sijst. Mijc. ii. 242 ; Berk. Int.
Crypt. Bot. 254.

PACHYMATIS'MA, Bowk.— A genus
of marine Sponges.

Distinguished by the fleshy, crust-like,
not celliUar nor elastic mass, covered by a
thick skin, and perforated by scattered ori-
fices f the interior beset with siliceous aci-
cular and stellate spicula. P. Johnstonia.
(Bowerbank, Bi-it. Spong., Ray Soc.)

PACHYPHLCEUS, Tul.— A genus of
Tuberacei (Ascomycetous Fungi), with a
common warty integument opening by a
terminal aperture with a distinct base, cla-
vate asci, and spherical sporidia. Three
species occur in Great Britain.

BiBL. Tul. Funy. Hyp. 130 ; Berk, and
Br. Ann. N. H. xiii. 3o9, xviii. 79 ; Berk.
Outl. 377 ; Cooke, Hondh. 743.

PACHYT'EOCHA, Kent.— A genus of
Peiitrichous Infusoria. Like Cotlmrnia,
but \A\\\ a fleshy pad closing the carapace.
P. cothurnoides ; pond-water. (Kent, Inf.
729.)

PAODs'IAN CORPUSCLES. — These
curious organs form terminations or appen-
dages of the spinal nerves in the skin and
subcutaneous tissue of the palm of the
hand, the sole of the foot, the fingers and
toes, in the sympathetic semilmiar ganglia,
the mesentery, &c.

They are elliptical or pear-shaped, whitish ,
and about 1-25 to 1-6" in diameter. Each
consists of from twenty to sixty concentric
layers of connective tissue (tig. 553), sepa-
rated by interspaces, those between the
outer layers being considerable, those be-
tween the inner being small ; each is lined
with epithelium. They surround a cavity
filled with soft, abinidantly nucleated and
very easily alterable material, which imder-
goes coagulation after death, and into the
interior of which the nerve-fibres penetrate.
They are filled with a clear serous Uqnid ;
each is also furnished with a stalk, contain-
ing a slender nerve-fibre, which passes into
the central space, in which it terminates,
frequently in two or three branches, each
■wnth a granular tubercle.

The Pacinian corpuscles are met with
also on the nerves of many Mammalia, and
are very numerous in the skin, the beak.

Fig. 553.

d

c
e

A human Pacinian corptiscle. a. stalk ; 6, nerre-flbre
within it ; c, outer, rf, inner layers of the sheath ; e, pale
nerve-fibre in the central cavity; /, its termination.
Magnified 350 diameters.

and the tongue of birds. Thev are readily
examined in the mesentery of the cat.

BiBL. Kolliker, Mile. An. ii. ; Schultze,
Strieker's Hist.

PADI'NA, Adanson.— A genus of Dic-
tyotacecs (Fucoid Algaj), containing one
species, P. Pavonin (fig. 554), found rarely
in summer and autumn on the south coast
of England. The fan-shaped or reniform
fronds grow in tufts, and are 2 to 5" high,
sometimes entire, sometimes cleft (fig. 5.54).
They are marked with concentric zones.
The substance is parenchymatous — the
number of layers of cells diminishing, with
the thickness and solidity, from the base to
the edges. The back of the frond is covered

PADINA.

[ 573 ]

PALMELLA.

by a layer of cells nmch smnllor than the
rest, forming a kind of epidermis, which
ultimately acquires a thickish cuticular

Fi?. 554.

Padina Pavonia.
Frond, one third natui-al size.

layer. The growing edge of the frond is
rolled backwards (circinate) and fringed.
The fructification occurs in linear concentric
sori, on the coloured zones of the frond.
The pear-shaped qiore-sncs (tig. oo5) origi-
nate from cells of the epidermal layer, which

Fig. 655.

Vertical section of a frond at a concentric zor.i , made
in a radial direction, cutting through the sorus of spore-
sacs and a line of hairs. The indusial layer of cuticle
has been removed.

Ma^ifled 50 diameters.

take on special development, and in the
course of their growth push up and finally
burst through the loosened cuticular layer
which originally clothed them, so that the
latter forms a kind of indusium Hke that of
the Ferns. The spore-sacs produce each
four spores, which separate after their escape
from the sac. The zones of the sori alter-
nate ■n'ith zones composed of tufts of jointed
hairs placed in corresponding lines (fig. 555).
Thuret states that he has never found
antheridia hitherto, and he believes that
Agardh mistook the hairs or paranemata
for them,

BiBL. Han^ev, Mar. Alg. 37, pi. 6 C ;
Thyc. Br. pi. 91 ; Grev. Ahj. Br. pi. 10 ;
Agardh, *S)>. Aly. i. 112; Niigeli, Algemyst.
180, pi. 5 ; Thuret, Ann. Sc. iVV. 4 ser. iii.

12 ; Kiitz. Phyc. gen. pi. 22 ; Al. Braun,
lieJHvenescence, Hay Soc, 1853, 79.

PALMEL'LA, Lyugbye (lied snow and
gory dew). — A genus of l'aliuellace;e (Con-
fervoid Alga)), of which the best known
example is the common P. crucnta (PI. 7.
lig. 3 rt). This plant, very common on damp
walls in shaded places, appears at first in
the form of rosy gelatinous patches ; these
spread and become confluent until the mass
extends sometimes over a great extent of
surface, as a tough, gelatinous, irregular
mass, of the colour and general appearance
of blood ; when dried up in this state, it
forms a horny, somewhat criunbling stra-
tum ; if placed in water, portions float to
the top in pellucid rosy masses of jelly.

When placed under the microscope, the
frond appears to be composed of a colourless
homogeneous jelly, in which are imbedded
globular cells, single or in pairs (from divi-
sion), of a beautiful rose-colour (fig. 3, a, b) ;
by the application of reagents, these may
be shown to possess a proper membranous
coat (c). The contents of the cells appear
uniformly granular (b, c) ; and it would
appear that, besides increasing by division,
the cells also burst and discharge their con-
tents, since patches of minute granules occur
imbedded in the jelly (lower figs, of b), pro-
bably destined to grow up into the ordinary
cells. No zoospores, nor the remarkable
phenomena generally that occm' in ProtcH
coccus, have yet been observed in this, which
appears to be a very distinct genus. The
jelly of full-grown fronds (which appears to
be derived from the gelatinous softening of
the coats of the parent cells of the successive
generations of cells) is often overgrown and
discoloured by minute filamentous struc-
tures, which at first sight seem to belong to
it ; but on the application of a higli power
are found to consist of a very minute Nos-
tochaceous plant, apparently the Anabaina
subtilissima of Kiitzing, or Vibrio bacillus,
Ehr. (PL 7. fig. 21), which we find to occur
commonly among the Pahnellaceous Algae.
From the examination of specimens of
the true "red snow," brought home by
Captain Parry, we incline to regard this as
a Pahnella, distinct genericaUy from the
Profococcus or Hfematococcus phtvialis of
German writers, with which it is commonly
associated. Our specimens consist of a
tough, colourless, gelatinous substance, con-
taining globidar cells difl'ering only in size
(PL 7. fig. .3 d) from those of Palmella cru-
enta ; and in the jelly occur also abundance

PALMELLACE^.

[ 574 ]

PALMELLACEzE.

of the minute granules or cells, wliicli are
the discharged contents of the larger cells.
The red cells of the red-snow plant turn
green when exposed to light, if kept moist.
An exactly similar plant has heen given us
by Mr. Oliver, from Crag Lough, North-
umberland, in a fresh condition ; and v^e
have never been able to detect any moving
forms in it. Further particulars are given
under Rkd Snow and Water. Several other
species of Pahnella are described ; but most
of them are too imperfectly known to allow
of definite characters being given ; P. rosea
is perhaps a good species. The forms with
a definite frond formerly placed here (P.
pi'otuberans, hotryoides, &c.) will be found
under Coccocitloris.

BiBL. Eng. Bot. pi. 1800 ; Greville, Alg.
pi. 205; Meneghini, Tr. Turin Ac. 2. v.
pi. 6 ; Hassall, Alg. pi. 80 : Niigeli, Alg. G6,
pi. 4D; Kiitz. 'Sp. Alg. 211; Rabenht.
Alg. iii. 32. See also Red Snow, and Pro-

TOCOCCUS.

PALMELLA'OE^.— A family of Con-
fervoid Algae, consisting of gelatinous or
pulverulent masses, growing on damp sur-
faces, in fresh water or in the sea ; composed
of globular or elliptical cells, either more or
less adherent together into a definite or
indefinite pseudo-membrane or frond, or
loosely aggregated within a definitely or
indefinitely formed gelatinous matrix, or
loosely coherent in the form of a pulverulent
crust. Some authors have imagined that
the cells of Coccochloris or Pahnella are at-
tached to filaments included in the gelatinous
frond: this seems an error (seePALMELLA).
Yellowish or bluish-green, or red, often
varying from green to red, and vice versa,
during the course of development. In-
creased by cell-division into two or four,
and by ciliated zoospores. Many exhibit
three forms: — 1. active; 2. quietly vege-
tating by subdivision ; 3. resting form,
with a tough membrane. We include here,
for the sake of convenience, not only the
true Palmellacese, where there is a frond
composed of a number of cells held together
by mucus, but also all those Unicellular
Algfe which, from their mode of increase,
are found living socially or in masses which
appear like Palmelloid plants.

Synopsis of Genera,

* Cells immersed in a colourless gelatinous
frond. t Frond amorphous.

Pahnella. Frond a slimy stratum, crowded

with rather large globular green and red
cells, multiplying by division (PI. 7. fig. 3).
Microhaloa. Frond mucoid, floating in
water, densely cro\\ded with minute cells,
multiplying by di^sision, green or red,

tt Frond dejinite.

Gloeocapsa. Cells enclosed in wide gela-
tinous coats, enclosed in similar wide gela-
tinous parent coats for several generations
(PI. 7. figs. 4 & 13).

Eotrydina. Frond globose, the peripheiy
composed of cells cohering into a kind of
cellular epidermis ; inner cells free (PI. 7.
fig. 9).

Coccochloris. Frond gelatinous, globose,
containing numerous distinct cells, all free
(PI. 7. fig. 6).

Clathrocgstis. Frond gelatinous, at first
globose, then hollow and broken into a
coarse net, crowded with minute cells (PI.
5. fig. 9).

Meris77iopcedia. Frond very minute, flat,
sc^uare, containing cells in families of four,
sixteen, and sixty-four (PI. 7. fig. 12).

Urococcus. Frond composed of striated
gelatinous tubes, formed of the parent cell-
membranes in a single row, with solitary
or binary cells in the ends (PI. 7. fig. 7).

Hormospora. Frond a wide, gelatinous,
simple or branched sheath, containing a
single row of cells in twos or foiu-s (fig-. 33B,
p. 395).

Tetraspora. Frond gelatino us, foliaceous ;
cells in fours, becoming free as zoospores
(PL 7. fig. 10). ■

Hydrurus. Frond toughly gelatinous,
filiform, containing imbedded longitudinal
rows of cells (PI. 7. fig. 8).

Pahnodictyon. Frond gelatinous, filiform,
branched; branches anastomosing into a net,
consisting of large vesicular cells, ^\•ith co-
loured contents which escape as zoospores.

** Cells single, either solitary or united
in small numbers into families (Unicellular
Algae).

Sckizochlamys. Cells free, globular, green,
aggregated in a jelly, each dividing into 2
or 4 portions, set free by the parent cell
breaking into 2 or 4 segments.

ChJorosphcera. A large free globose cell,
with green contents, ultimately dividing
into two cells, each forming a new cell like
the parent, set free by lateral rupture (PI. 5.
%• 4).

Characiunt. A minute attached, pyriform,
fusiform, or roimded, shortly stipitate sac

PALMELLINA.

[ -'"'75 ]

PALUJJICELLA.

containing green protoplasm, wliicli by re-
peated biuar}' division forms a swarm of
active 2-ciliated zoospores escaping by a
lateral or terminal slit (PI. 5. tig. 2).

Apiocystis. A simple attached sac with
a stout membrane, with green contents,
consisting at fii"st of groups of four still
gonidia, which subdivide repeatedly, and as
the parent sac grows become converted into
innumerable active zoospores, which mt)ve
in the paient sac and then break out in a
swarm (PL 5. tig. 6).

Codioium. An attached small, long cla-
vate sac, forming a stipes below, tilled Avith
granular green contents, with starch-corpus-
cles, finally converted at once into nume-
rous globose gonidia, escaping by ruptm-e of
the sac (PI. 5. fig. 6).

Hydrociftium. An attached minute shortly
stalked oblong sac, with green contents, and
a parietal starch-corpsule. Contents finally
divided into uiunerous 2-ciliated zoospores,
breaking out in a swarm (PL 5. fig. 1).

Ophiocyfium. Single or rarely in families ;
composed of a minute cyhndrical cvirved
sac, v\-ith a short stipes, jfree or attached ;
green contents scattered, finally forming 8
gonidia in a row, set free by the circumscissile
rupture of the end of the sac (PL 5. fig. 11).

Sciadiiim. A t first a stalked tubular sac,
with 8 gonidia, which grow fi-om the orifice
in an umbel, finally emitting 2-ciliated zoo-
spores (PL 5. fig. 3).

C'hytridmm. A minute parasitic globu-
lar or urceolate rooted sac ; cell-contents
colom'less, finally converted into 2-ciKated
zoospores (PL 5. fig. 7).

Pythium. Parasitic ; a coloiu'less globu-
lar sac, living m the interior of diseased
Confervoids, often in groups, the neck per-
forating the nm-se-plant, emitting active
gonidia (PL 5. fig. 8).

BiBL. Braim, Hejuven., Hay Soc. 1861 ;
Alg. Unicell. 1855 ; Chytridium, 1856 ;
Nageli, Eiir^eU. Alyen, 18'49 ; Kiitz. Sj)ec.
Aly. and Tah. Phycol. i. ; Cohn, Noca Acta,
xxiv. ; Kabenh. Aly. iii. ; Cooke, Fresh-
icaicr Alyce, 1882.

PAL.MELLI'NA, Radlk.— A doubtful
genus, allied to PahncUa, or probably Fmigi.
Thallus fl Occident ; cells very minute, some
smaller and globular, others larger, elliptical
or elongate. In the mud of wells and
fountains ; and beneath the epidermis of
the scalp !

BiBL. Rabenh. Aly. iii. 35.

. PALME'RIA, Grev.— A genus of Dia-
tomacese from Hong Kong.

BiBL. Grev. Ann. N. H. 1865, xvi. 1.

PALMICELLA'IUA, Alder.— A genus
of Escharida3 (Cheilostomatous Polyzoa).
Orifice of the capsules with a palmate or
mucrouate process, with an avicularium on
its inner aspect. Four species ; marine,
deep water. (Hincks, Br. Zooph. 378.)

PALMITIC ACID is a constituent of
most neutral animal and vegetable fats ; it
exists in combination with glycerine, form-
ing palmitine. When crystalline it forms
pearly scales.

PALMODAC'TYLON, Nag.— A sup-
posed genus of Unicellular Algae, germina-
ting spores of a Moss ?

P. varium consists of a group of radiating
single cells, or short multicellular filaments ;
ends rounded; numerous green masses in
each cell. The cell-wall bursting in definite
directions, sets free active gonidia. In
freshwater pools.

BiBL. Nageli, EmzeJl. Aly. pi. 2. fig. B ;
Rabenh. Alq. iii. 43.

PALMODIC'TYON, Ktz.— A genus of
Palmellacese (Confervoid Algse). Frond
forming a delicate gelatinous network, com-
posed of single or double rows of large vesi-
cular cells, 1-600 to 1-960" in diameter;
containing a pair of eUiptical gi-een cellules,
1-3000" in diameter, which ultimately es-
cape as active zoospores. This genus ap-
pears identical with Tryjwthallus, Hook,
and Harvey, and is nearly related to Hy-
DEURXJS and Tetbaspoea.

P. rufescens, Ktz., doubtfully referred
here, is larger ; it occurs near Aberdeen.

BiBL. Kiitz. -§j. Aly. 234; Tah. Phyc.
Bd. i. pi. 31 ; Rabenh. Aly. iii. 37.

PALMOGLCEA, Ktz. See Cocco-

CHXORIS.

BiBL. Archer, Qu. Mic. Jn, 1864, 124;
Rabenh. Aly. iii. 116.

PALMOPHYL'LUM, Ktz.— A genus of
Palmellacese (Confervoid Algae). 1 species,
found in the Adriatic.

BiBL. Rabenht. Flor. Eur. Aly. iii.
49.

PALUDEL'LA, Ehr.— A genus of Mee-
siaceae, having • only one representative,
which occurs in Britain, P. squarrosa =
Brxjum squarrosum, L.

PALUDICEL'LA, Gervais.— A genus of
Polyzoa.

Char. Polyzoary fixed, filamentous, dif-
fusely and irregularly branched, coriaceous,
consisting of a single row of club-shaped
cells arranged end to end ; apertures unila-
teral, tubular, placed near the broad end of

PAMPHAGUS.

[ 576 ]

PAPER.

each cell ; tentacular disk circular, with a
single row of free tentacles.

F. articidala. The only species ; olive-
green ; polypes ascidian. Freshwater ; dia-
meter of filaments about 1-30 to 1-20".

BiBL. Johnston, £r. Zooph. 405 ; All-
man, Ann. N. H. xiii. o31, and Pr. Irish
Ac. 1843.

PAM'PHAGUS, BaUey. — A genus of
Rhizopoda allied to Lieherkuehnia. P. mu-
tabilis is auicebiforni, covered with a delicate
elastic integument. Bailey, Amcr. Jn. Sei.
XV. ; Pritchard, Inf. 551 ; Claparede et
Lachmann, Etudes, 465 j Archer, Qti. M. J.
1871, 101.

PANDORI'^^A, Bory (PL 5. fig. 10).—
A genus of Volvocine£e (Confervoid Algas),
which we believe to be synonymous with
Eudorina, It exhibits a great variety of
forms, some of which have been described
under the name of P. Monim.^ others of End.
eUyans. The most characteristic conditions
are represented in PI. 5. fig. 10. Pandurina
stands midway between Volvox and Ste-
phanosphcera, — consisting of an ellipsoidal
translucent gelatinous sac, containing im-
bedded just within its surface, several zone-
like rows of green pear-shaped gonidia,
whose two cilia penetrate the gelatinous
envelope, and, hanging out free, move the
entire organism by their vibration. Two
distinct forms occur — one with sixteen, the
other with thirty-two gonidia. Where
sixteen occur, there are four zones of four
gonidia, while where thirty-two exist they
stand in four zones of eight, %vith four at each
end(Pl. 5. fig. 10 a and Z»). The gonidia
have a red spot and a vacuole, like those of
Gonium and Volvox. These two forms
occur together; and evidently the difference
arises simply from an additional binary sub-
division of the gonidia in the earlier stages
of development from the spore. They are
often so numerous as to tinge the water of
fresh pools gi'een, like Volvox and Proto-
coccus. They occur of various sizes, from
1-80" downwards.

These forms are multiplied vegetatively
by the conversion of each gonidium into a
family like the parent, each group acquiring
its special envelope and becoming free by
the solution of the parent-envelope. Two
corresponding forms also occur with the
above, with the sixteen or thirty-two goni-
dia closely crowded together, instead of
standing at wide intervals in the large
colourless envelope.

The resting-spores are formed out of all

or part of the gonidia of a family, after
conjugation (fig. 13U*, p. 205). The impreg-
nated gonidia soon acquire a stout special
coat, and their originally gi-een contents
turn red ; they become free by the solution
of the parent-envelope. In germination
they turn green again, and by repeated
division of their protoplasm, form the new
families of sixteen or thirty-two, constitu-
ting the perfect plant.

Fertilization of the gonidia has also been
described as being produced by the action
of spermatozoids — minute, fusiform, ciliated
corpuscles, produced in large numbers by the
subdivision of certain of the gonidia. This
seems doubtful.

BiBL. Ehr. Inf. 53; Duj. Inf 317;
Henfrey, Mic. Tr. 2. iv. 49 ; Fresenius,
Mus. Senckenb. ii. 187 ; Cohn, Nova Acta,
xxvi. 1 ; De Barv, Bot. Zeit. xvi., Supp. ii.
73 ; Currey, Q. Mic. Jn. vi. 213 ; Carter,
Ann. N. H. 3 ser. ii. 237 ; Rabenhorst,
Alq. iii. 99 ; Pringsheim, Monatsb. Berl.
Ak. 1869 ; Sachs, Bot. 258.

PANNA'RIA, Del.— A genus of Placodei
(Lichenaceous Lichens). Several species.
(Leighton, Licli. Fl. ] 50.)

PANOPH'RYS, Duj. = rRONTONiA pt.

P. ckri/salis (PI. 31. fig. 55). Marine.

BiBL. Duj. Inf. 491; Claparede & Lachm.
Etudes, 260.

PANTOT'RICHUM, Ehr.— A genus of
Infusoria.

P. kif/ennla, E. (PI. 31. fig. 58). Body
ovate, equally rounded at each end, yellow-
ish ; tegument produced in front in the
form of a neck or truncate rostrum ; length
1-1080 to 1-580".

BiBL. Ehrenberg, Inf. 247; Dujard. Inf.
388 ; Clap, et Lachm. Inf. 315.

PAPER. — A few general observations
only can be made under this head. Ordinary
paper, as is well known, was generally manu-
factured from rags of linen or cotton f abi ics,
so that it consisted of a kind of felt of the
fibres of cotton or flax ; but in consequence
of the immense demand for paper, other
substances, such as straw, jute, esparto, the
pulped woody fibres of the poplar and pine,
are now largely used. The manipulation
to which the material is subjected, together -
with the effect of frequent washing in the
case of rags, affects the - characters of the
fibres to some extent; and the cellulose is
in some cases already brought into that
state in which iodine colours it blue. The
addition of sulphuric acid and iodine colours
the fibres of most papers blue ; and care

PAPER.

[ .577 j

PARAaiTES.

must be takeu on this accouut to avoid
errors from the accidental presence of them
■\vlien blotting- -paper is used to absorb these
reagents when applied to objects on a slide.
The determination of the nature of the tila-
ments of which a paper is composed, by tlie
aid of the microscope, requires a thorough
knowledge of the characters of vegetable
fibres. The structure of the various fibres
is noticed under the individual heads. Lat-
terly the use of the fibres of the purple bog
melic-grass, Molinea ccerulea, has been in-
troduced.

Rice-paper, as it is termed, is a totally
different material, consisting of thin layers,
cut by a peculiar operation, of the pith of
Aralia papyrifera, a Chinese Araliaceous
tree : this consists of parenchymatous cel-
lular tissue.

Papyrus, consisting of pressed superposed
lamina? of the pith of the Papyrus plant,
Papyrus antiquorum, a kind of Sedge, ex-
hibits the lax parenchymatous structure
chaiacteristic of similar tissues, as in the
Rushes, &c.

PAPER, METEORIC, and Aeeophytes. —
The structure of these substances is the
same as that of the so-called natural Hanuel
(Flanistel). They were formerly regarded
as of meteoric origin. They have been ob-
served in some in.^tances to fall from the
air, having been wafted perhaps many miles
from their place of formation by whirlwinds
and hurricanes.

BrBL. Ehr. Abhandl. d. Berl. Akad.
1838.

PAP'PUS.— The free portion of the
calyx of the Compositse. It may be
featherv, spiny, membranous, or hairy.

PAPULASTORA, Preuss.— A genus of
Mucedines (Hyphoniycetous FuugiJ, con-
sisting of a decumbent articulate mycelium
sending up erect pedicels bearing a cellular
head, each cell supporting an oblong spore.

P. sepedonioides has been found on rice-
paste.

BiBL. Berk, and Broome, Ann. N. H. 2.
xiii. 4G2 ; Berk. Crijpf. Bot. 305, fig. 69 b.

PAPY'RUS.— The pith of the stem of *
the Papyrus antiquormii (modern papyrus
from P. syrtacus), cut into slices, which are
laid upon one another and pressed so as to
form a compact stratum. Sections display
the parenchymatous tissue more or less de-
formed bv pressure.

PAPACY 'PRIS, Sars. — A genus of
Cypridce (Entomostraca), near Ayluia and
Potamocyyris. One British species, rather

common, marine ; also fossil in raised
beaches, &c. (Brady, Zm«. 2/-. xxvi. 377.)
PARADUXOS'TUMA, Fischer.— A ge-
nus of Cytheridce (Entomostraca). Valves
thin, smooth, elongate, compressed, sub-
ovate or subtiiangular ; mouth simple, tubi-
fbrm ; five joints in the lower, six in the
upper antennte, the last very slender.
Marine ; 13 British species. P. variahile
very common, fossil in raised beaches, &c.
(Brady, Linn. Tr. xxvi. 456.)

PARAME'CIUM, Hill, Ehr.— A genus
of Holotrichous Infusoria, family Colpodina.
Char. Body compressed, covered with
cilia ; no eye-spot ; moutii lateral and with-
out projecting cirri.

Several species, freshwater and marine.
P. aurdia (PL 31. figs. 56 and 57). Body
cylindrical, ovate-oblong, rounded or obtuse
at the ends, with an oblique longitudinal
fold extending to the mouth. Length 1-120
to 1-100" ; in vegetable infusions.

This common infusorium shows well the
curious star-shaped contractile vesicles.
Ehrenberg notices in it the periodical occur-
rence of small black crystalline particles at
the anterior end. The depressions on the
surface of the integument (PI. 32. tig. 1) are
distinctly seen in the dried animal ; tri-
chocysts are present.

P. chrysalis, E. (^Pleuronem'i crassum, D,
PI. 32. fig. 37, undergoing division). Body
oblong, cylindrical; oral cilia very long.
Length 1-2-10".

BiBL. Elir. Inf. 349; Duj. Inf. 481;
Stein, Infus. ; C laparede et Lachmann, Infus.
265 ; Kent, Inf. 483.

PARAISJ 'UNAS, Kt.— A genus of Fla-
gellate Infusoria. Free, ovate or globular,
one tiagellum, a distinct mouth at its base-
Four species, white, red, or green ; fresh-
water. (Kent, Inf. 370.)

PARAPHY'SES.— The name apphed
to more or less delicate-jointed, hair-like
filaments Avhich occur in small numbers
around and between the antheridia and
archegonia of Mosses and Hepaticse (fig. 23,
p. 57, fig. 327, p. 388). The same term is
applied to simple tubular, more or less
clavate cells, occurring in large numbers
among the spore-sacs (asci and thecce) of
the Ascomycetous Fungi and the Lichens
(fig. 40, p. "78; fig. 398, p. 463; PL 37.
figs. 6, 12).

PARAPONTEL'LA, Br.— A genus of

Copepodous Entomofttraca. P. brevicornis,

marine. (Brady, Copepoda, Hay Soc. i. 68.)

PARASITES. — Under this head are in-

2p

PARASITES.

[ 578 ]

PARASITES.

eluded a uumber of microscopic animals
and plants infesting other animals and
plants, and often nourished at the expense
of their structures or juices. Almost eveiy
animal and plant is subject to parasites,
both in the young and the adult state ; and
in some instances, the parasites are them-
selves infested by other parasites. The
parasite may live on the surface of the
parasitiphore or host, or within its tissues
and in the cavities of its organs ; hence the
division of parasitic animals into epizoa
and entozoa. The commonest parasites
either feed upon the deca;y'ing external
skin -tissues, or are nourished at the expense
of the blood and fluids. In some remark-
able instances, as in the cirripeds, the male
appears to live parasitically upon the fe- I
male ; and in almost every case of para- '
sitism there is a complicated life-cycle, often
accompanied by strange adaptations and
degenerations of form, so that often the
parasite ultimately resembles but slightly its
free and primitive form. Of the Animal
Parasites, many are not microscopic, but
the following sketch may be useful for
reference. The chief portion belong to : —
The Crustacea, Order Siphonostoma, as
Caligus, Cecrops, Lcemargus, Nicotho'e. The
Aeachnida, Ord. Acariua, as Sarcoptes,
the itch-insect ; the Ixodea, or ticks ; the
Gamasea, on insects ; Tromhidium, the
harvest-bug; the Hypoderidee, in birds;
the Phytoptidse, in galls. The Insects,
especially the Anoplura, as Htsmato^nnus,
Pediculus (the louse), and Phthirius ; Pedi-
cimis ; and TricJiodectes. The Entozoa,
as Tcenia {Ccenunis, Cysticercus, Echino-
coccus) ; Distoma, in the hver; Bilharzia,
in the human blood-vessels, the ova in the
lU'iiie in endemic hsematuria and chyluria ;
the Nematodes, Anyuilhda intest. and ster-
coralis, and TJocJimius, in tropical diarrlicea ;
Sderostoma synfjamiis in poultry, producing
the " gapes;" Stromjylns 2}eryrucilis in the
Grouse-disease. The Infusoria, Oj)alma,
Trichomoyuis, &c. ; and the Gregabinida,
Psorospermice in mammals, and insects
(Pebrine).

These are described under the respective
heads.

The Plants parasitic on animals chiefly
belong to the class of Fungi, and are tole-
rably numerous ; but many of the forms
which have been described are certainlj"
not distinct plants. They will be most con-
veniently emmierated under the heads of
the classes of animals infested.

Man and Mammalia.

On the Skin. — Achorion Schcenleinii and
Puccinia favus, on the hair and in the
follicles, in favus. Trichophyton ton-
siiranSf on the hair in plica polonica and
favus ; this appears to be a Tonda-like
growth, probably not a mature plant. Tr.?
spondoides, Rob., occurs in plica ; and Tr.?
ulcerina, Rob., in the pus of ulcers. Micro-
sporon Audouinii occurs in the hair-fol-
licles in porrigo decalvans : M. metdagro-
phytes. on the beard &c. ; M. fiirfiir, on the
skin of the chest tS:e. in pitja-iasis versicolor.
The occurrence of 3Iuco)- mucedo on the
skin, and of an Asj^ergillus in the external
conduit of the ear, must be regarded as
accidental.

On tlie mucous surfaces or in cavities. —
Sarcina ventricidi in the stomach ; Torula
cerevisice (?), ditto. Various species of
Leptomitus, which must be regarded as
imperfect mycelial growths, found in almost
all the cavities of the body. Oidium albi-
cans, the fimgus of aphtha, probably a pe-
culiar condition of PENicii,LirM;'ie/;;'o-
tlirix hiccalis, a filamentous growtli constant
between the teeth, probably some allied
mycelium.

Birds.

Various species of Aspergillus have
been found in the kmgs and air-sacs ; their
introduction would appear to be accidental.
In the eggs of the common fowl, Dacty-
LiuM ooyenum occurs not imfrequeutly,
sometimes on the membrane of the yolk,
sometimes on the outer membrane, just
beneath the shell. — Sporotrichum hrun-
neunt, Schenk, in the white of eggs, convert-
ing it into a brownish gelatinous mass.

Iteptiles and Fishes.
On the skin of Tritons, as of Fishes,
Achlya {Saproleynia) is frequently ex-
tremely developed ; other obscure forms are
also enumerated by Robin. The same author
describes the Psorospeemi^ as Algfe allied
to the Diatomacea; ; but they are pseudo-
navicidaj of Gregarina.

Berkeley has recorded the occurrence in
Denbighshire, on the scales of goldfish, of a
'\ lichen identical A^dth one wliich is found on
stones in neighbouring streams.

Insects

are subject to the invasion of various para-
sitic fungi, among the most remarkable of

PAKASITES.

[ -"'J ]

PAILMKLIA.

which is the 3Iuscardine of tlio Silk-wurm,
BoTRYTis ba^siaiia, which soiUL'limcs occii-
sions euoruious loss to the silk-cidtivators.
This fungus grows in or upon auy part of
the silk-worm, Bombi/.v mori, iu its larva,
chrysaHs, aud imago forms. It is not fully
developed until after the death of the insect ;
but if the spores penetrate the body of a
living specimen and this is placed iu a damp
and contined atmosphere, the germination
takes place, aud a development of the fungus
ensues, which destroys the tissues and organs,
finally causing death. It has been developed
on many other Lepidoptera which have
been inoculated with it ; and even the larva)
of certain Coleoptera take it. It is very
common to hud flies iu autumu infested
with a f migus, a kind of muscardine of tiies :
this belongs to the genus Spohendonema ;
its mycehal filaments ramify in the interior
of the body, and emerge at the articulations
of the segments of the abdomen to bear fruit,
killing the fly. A number of so-called genera
of Fungi and Alg8e have been described by
Eobin and Leidy as occurring in the intes-
tines &c. of insects : these appear to us to
be imperfect organisms (see Enterobryus,
Aethrojxitus, Leptothrix, Cladophy-
titm). Several species of Cordyceps infest
the larvae of insects, the mycelium destroy-
ing them aud gradually completely dis-
placing the internal organs, while the skin
retains its shape and dries ; the fruit sub-
sequently breaks out from the anterior or
posterior extremity (see Sph^ria). Some
species of Isaria, described as parasites,
gro\\- upon dead insects ; but these are mere
conditions of different species of Cordyceps.

The microscopic vegetahle parasites of
Plants

are very numerous, all belonging to the class
of Fimgi. Much confusion exists in many
works between the true parasites and mere
epiphytes ; and it is sometimes very difficult
to draw any line of demarcation. Among
the undoubted parasites are all the genera
and species of the family Uredinei, together
with a large portion of the other genera of
Coniomycetes and the Ascomycetous forms
to which they mostly belong. Among the
Hyphomycetes may especially be cited the
genus Peroxospora, P. infestamheiug the
potato-fimgus. Fusisporium, Oidium, &c.
form desti'uctive mildews ; and among the '
Ascomycetes, the Erysiph^, and espe-
cially their mycelia (commonly forming-
spurious Oidid), ar^' v>ell-kiio\vn pests. (

Further particulars are given under Potato-
FifNGUS {Butrytis infestam) ,\ i^k-Fxjsgvh,
and Bligut. The organisms described as
Unicellular Alga3, under the names of
Chytridium and Pythium, are parasitic
on Confer voids.

BiBL. Robin, Vcyet. Parasit. ; Bseren-
sprung, Ann. N. II. xii. ; Siebold, Wayner\s
Hand. d. Pliys.-, Hdunoyev, MuUer''s Arc/t.
1842 ; Beimett, Bd. Phil. Tr. xv. ; Archer,
Qu. Mic. Jii. 1872, 366 ; Cobbold, Parasites ;
Leuckart, Mensch. Parasit. 18S1 ; Murio,
Mn. M. Jn. vii. 149 ; .^laddox, Mic. Tr. 1866 ;
Beneden, Schmarotzer,\S7Q; Hallier, P%^o-
pathol. 1868 ; Kaltenbach, Pflanzcnfeinde
(Insects), 1872 ; Giebel, Epizoa {Insects),
1874; Bounon, Par. diar. Cochin- China;
Gurlt, ^4rc/<. Nataryesch. 1878, 162 j ITartig,
PJlanzenKr. (Funyi), 1S80; Frank, AVawM.
P/l. {Funyi), 1880 ; Heller, Schmarotzer,
1880 ; Megnin, Paras. 1880 ; Ormerod, In-
jurious Insects, 1881 ; Cuhn, Paras. Alyce,
Beitrage, i. 87 ; Kiichenmeister, Parasiten,
1881 ; Bollinger, Pilzhranhh. nied. und
hah. Thiere, Bot. Centralblatt, ii. 274 (Jn.
Mic. Soc. 1881, 492) ; Halher, Zeitschr.
Paras. Kunde.

PAPtEN'CHYMA. See Tissues, Vege-
table.

PARKE' RI A, Carpenter. — A large
spheroidal Arenaceous Foraminifer, attain-
ing 3 inches and more in diameter, and
consisting of a chambered conical centi'e-
piece (primordial chamber-cone) surrounded
by numerous concentric lamellae and their
interspaces, traversed aiid connected by
radial tubes, all of cauueilated (labyrinthic)
structure. Fossil in the Greensand.

BiBL, Carpenter, Phil. Trans. 1869, 721.

PARKE'RIA, Hooker, = Cerato-

PTERIS.

PAR^IE'LIA, Acli. — An extensive genus
of Parmeliacese, characterized by the spread-
ing, lobed, foUaceous thallus, with orbi-
cular apothecia fixed by a central point
beneath ; spores simple ; growing upon
trees, palings, rocks, stones, walls, &c.
The species with bilocular spores form the
genus Physcia. P. parietina, the yellow
wall-Uchen, is one of the commonest plants
of this family, and furnishes a ready means
of observing the structm-e both of the
apothecia and the 'spermogonia (PL 37.
figs. 1-3).

BiBL. Hook. Br. Fl. ii. pt. 1. 202; Engl.
Bot. pi. 194 ; Schaerer, Enum. Lich. Europ. ;
Tulasne, Ann. Sc. Nat. 3. xvii. 66, 137 :
Leighton, Lich, Flora, 114.

2p2

PAKMELIACE^.

[ 580 ]

PATELLINA.

PARMELIA'CE^.— A family of open-
fruited Lichenaceous Lichens, beaiing ses-
sile shields, tlie borders of which are formed
by the surface of the th alius. This family
corresponds nearl}' to the series Eamalodei,
Phyllodei, and Placodei, of the family Li-
chenacei in Leigh ton's B}'it. Lich. Flora.

British Genera.

* Apotheeia atjirst veiled, thallus horizontal :
Peltigeri.

Peltif/era. Thallus foliaceous, leathery
or membranons, spreading, lobed, with
woolly veins beneath. Apotheeia somewhat
circular, adnate on the upper side of the
lobules of the thallus, with a border fomied
by this.

Kephroma. Thallus foliaceous, leathery
or membranous, spreading, lobed, naked or
hairy beneath. Apotheeia circular or reni-
form, adnate on the underside of the lobules
of the thallus, vnih a border formed by the
latter.

Solorina. Thallus leathery, membrana-
ceous, veined or fibrillose below. Apo-
theciwn suborbicidar, affixed to the upper
sm-face of the central lobes of the thallus ;
veil finall}' forming an evanescent margin.

^"^ Apotheeia at first closed, thallus horizontal :
Euparuieliacei.

Sticta. Thallus fohaceous, leathery-car-
tilaginous, spreading, lobed, free and downy
beneath, with little cavities or hollow spots,
often containing a powdery substance. Apo-
theeia beneath formed of the thallus, to
which thej'^ are appressed and fixed by a
central point, the disk coloured, flat, sur-
rounded by an elevated thalline border.

Parmelid. Thallus foliaceous, membranous
or leathery, spreading, lobed and stellated
or laciniated, more or less fibrous beneath.
Apotheeia circular, formed by the thallus,
fixed by a central point, disk concave,
coloured, with an infiexed margin from
the thallus.

Urceolaria. Thallus luiiform, crusta-
ceous. Apotheeia urceolate, somewhat im-
mersed, the thalline border somewhat di-
stinct.

Lecanora. Thallus crustaceous, spread-
ing, flat, adnate and uniform. Apotheeia
circular, thick, sessile and adnate; disk
plano-convex, the border thickish, formed
of the crust, and of the same colour.

Physcia. Thallus caililaginous, branched
and laciniated, the segments free, generally
grooved beneath, the margins frequently

ciliated. Apotheeia circular, peltate, foi-med
of the thallus, the disk coloured and sur-
rounded by an inflexed thalline margin.

*** Apotheeia open fro7n the frst, thallus
mosfl)/ centripetal, veHieal or sarmen-
tose, without any hypothallus : L^snei.

Cetraria. Thallus foliaceous, cartila-
gineo-membranous, ascending or spreading,
lobed and laciniated, smooth and naked on
both sides. Apotheeia circular, obliquely
adnate to the margin of the thallus, the
lower portion being free (from the thallus) :
disk coloured, plano-concave, with an in-
flexed thalline border.

Roecella. Thallus cartilaginous, leathery,
rounded or flat, branched or laciniate.
Apotheeia circular, adnate to the thaUus,
disk coloured, plano-convex, with a thalline
border, at length thickened and elevated,
and covering a black powder concealed
within the substance of the thallus.

Ramalina. Thallus cartilaginous, gene-
rally branched and laciniated, somewhat
shrubby, generally bearing powdery wai-ts,
cottony and compact within. Apotheeia
circxilar, shield-shaped, stalked and peltate,
flat, bordered, entirely formed of the sub-
stance of the thallus, and mostly of the
same colour.

Cornicularia. Thallus cartilaginous,
branched, subcylindrical, fistulose, or nearly
sohd and cottony within. Apotheeia cir-
cular, tenniual, "obliquely peltate, entirely
formed of the substance of the thallus, at
length convex, more or less bordered and
often toothed.

Evcrnia. Thallus somewhat crustaceous,
branched and laciniated, angled or com-
pressed, cottony within. Apotheeia circular,
shield-shaped, sessile, with the disk concave,
coloured, and an inflexed border formed by
the thallus.

Usnea. Thallus somewhat crustaceous,
rounded branched, generally pendulous,
with a central thread. Apotheeia circulai-,
terminal on processes of the thallus, peltate,
nearly of the same colour, mostly without a
raised border, but ciliated at the margins.
BiBL. See the genera.
PASTE, Eels ix. See AxGUiLLrLA.
PATELLI'NA, Will.— A genus of Hya-
line Foraminifera, of the Ilotaline family.

Trochoid, formed of a low cone of sub-
spiral, seraiannular, and annular chambers,
divided into chamberlets. Sometimes in-
crusted with small cells externally, and

i'AVONlNA.

[ o81 J

PEDALIOX.

always having llie hollow face cuated or
tilled up with superiuiposed chanibeilft.s,
forming a columnar chamber-structure.

British species, P. corrugata (I'l. 24.
tig. 8), rare : abundant in tropical seas ; and
of larger size in some Cretaceous and Ter-
tiary strata.

BiBL. Williamson, 7?ec, For.AQ; Carter
{Cvimlites and Orbitolinci), Ann. N. H. 3.
viii. 331, 457, 459 ; Carpenter, Introd. For.
299.

' PAVONI'NA, D'Orb.— A Hyaline Fora-
minifer, compressed and liabelliform ; cham-
bers concentric, the last widest, with
numerous marginal apertures. It is a tlat
Bigenerine Textularia. Madagascar, Pacific,
and West Indies.

BiBL. Brady, Ann. N. H. 4. xix. lOo ;
Qu. Mio. Jn. n. s. xix. 68.

PAXIL'LUS, Fr. — A genus of Agariciui
(^Hymeuomycetous Fungi) with the margin
of the pileus involute, the gills decurrent,
auastomosing, and separable from the pileus
and without any trama. Paxillus involutus
is a very common species ; and to this the
characters of the genus more especially
apply. P. inmnoides occurs on sawdust in
cellars &c., and is closelv allied to Merulius.

BiBL. Fr. Gen. Hym. 8; Berk. Outi.
t. 12. fig. 5: Cooke, Handh. 194.

PEARLS. — These well-known bodies are
formed as secretions from the mantle of
bivalve mollusks, the best being obtained
from the Cej'lon pearl-oyster or mussel
(Avicula maryaritifera). They occur natu-
rally from the irritation produced by particles
of sand accidentally confined betAveen the
mantle and the shell ; and they are produced
artificially by wounding the mantle with
pieces of ii-ou wire, &c. Their structure
agrees with that of the shell of the animal
in which they are formed. Sometimes they
consist entirely of nacre or pearly matter,
arranged iu close concentric layers; at
others, the interior exhibits the prismatic
sti'ucture of sheU. When acted upon by a
dilute mineral acid, the lime-salt is removed
from the organic cast of the original, which
is left. They are sometimes found fossil.

See Shell.

BiBL. Hague and Siebold, Siebold <$• Kdl-
liker's Zeitschr. viii. 439 & 445 ; Carpenter,
Microscope.

PEB'illNE is the name of a disease

•which for the past twenty years has raged

amongst the silkwoi-msin France, In 1853,

the weight of cocoons produced in that

country was 26,000,000 of kilogrammes ; iu

1805 it had fallen to 4,000,000. The black
spots wliich cover the larv;e are a frequent
outward sign of the disease ; hence the
name pehrine, first applied to the plague by
Quatrefages. It also declares itself iu the
stunted and unequal growth of the worms,
in the languor of their movements, in their
fastidiousness as regards food, and iu their
premature death. The cause of the disease
is the presence in the internal economy of
the larvie of Gregariaida \ their number is
often enormous. They take possession of
the intestinal canal, and spread thence
through the rest of the body. In particular,
the silk -secreting organs, instead of being
filled with the clear viscous liquid of the
silk, are packed to distention by these cor-
puscles. Pasteur in 1805 made out the
fact that they might exist in an incipient
condition iu the eggs and larvae, although
it might be impossible to detect them. In
the moths, if either egg or larva from
which they come should have been at all
stricken, the corpuscles infallibly appear,
and there is no dilficulty in detecting them.
In eradicating the disease, Pasteur, there-
fore, showed that it was of the greatest
importance to secure eggs from healthy
moths, since the healthy appearance of the
eggs themselves was not sufficient to secure
immunity. The larvaj issuing from the
eggs of perfectly healthy moths may them-
selves become infected thi'ough contact
with diseased larvae, or through germs
mixed with the dust of the rooms in which
the silkworms are fed.

BiBL. Pastern", Maladie des vers a sole;
Tvvidall, Nature, 1870 ; Balbiani, Jn. Anat.
18G6, 599 ; Robin, Micr. 948.

PECTIN ATEL 'LA, Leidy.— A genus of
freshwater Polyzoa, order Hippocrepia,
family PlumatelUdfe.

Char. Zoary massive, gelatinous, fixed,
investing ; orifices arranged in ii'regidar
lobate areolae upon the free surface ; ova
lenticular, with a ring and marginal spines.

P. niaynlfica. Philadelphia.

BiBL. Leidy, , Proc. Ac. Philadelphia,
1851 ; AUman, Freshwater Polyzoa, 81.

PEDA'LION, Hudson.— A genus of
Rotatoria, family Hydatinfea, P. tnirum
has the trochal disk very large, and resembles
2'riarthj-a lonyiseta. ' The males are very
smaU, and deficient in most of the inrnal
organs ; freshwater.

BiBL. Hudson, Mn. Mic. Jn. 1871, 1872;
Qu. Mic. Jn. 1872, 333; Lankester, Qu.
Mic. Jn. 1872, 338.

PEDIASTRUM.

[ o82 ]

PELLIA.

PEDIAS'TRUM, Meyen.— A geuus of
Desmidiacefe (Confervoid Algee).

Char. Cells aggregated into a usually
circular, minute disk or flattened star, and
generally arranged either in a single or in
two or more concentric series ; marginal
cells bipartite on the outside.

lialfs describes eleven British species.
Interstices of the cells usually hyaline, but
in P. selcnceum these are greenish.

Rraun divided the genera into four sub-
genera, which include twenty-nine forms
more or less worthy of being considered
genera.

P. Boryanum (PI. 14. fig. 4S). Cells
arranged in one or more circles around one or
two central ones ; marginal cells gradually
tapering into two long subulate points ;
notch narrow. Diameter of outer cells
1-2730 to 1-2200".

P. granulatmn (PI. 14. fig. 49). Cells
six, granular or punctate on the svu'face ;
lobes of marginal cells tapering. Diameter
of outer cells 1-18-50".

The method of reproduction is noticed
under Desmidiace^, p. 244.

Bii3L. Ralls, lir. Desmid. ISO ; Braun,
Eejuv., Ray. Soc. 1853, pis. 3 & 4; Aly,
XJnicell. Gen. Nova, 64; Rabenh. Aly. iii. 09.

PEDICELLA'RI.E. See Echinoder-

MATA.

PL 45. fig. 3 represents a pedicellaria
from the common starfish ; the stalk is not
figured.

The bird's-head processes of the Polyzoa
(Polyzoa) are analogous organs.

PEDICELLI'NA, Sars.— a genus of
Ctenostomatous Polyzoa, family Pedicelli-
nidte.

Char. Those of the family.

Bodies globose, with a circle of short
tentacles, curled inwards and not retractile ;
placed at the ends of erect slender stalks
springing from a creeping adherent fibre.
3 species.

BiBL. Johnston, Br. Zooph. 381 ; Allman,
Polyzoa, Pay <S'oe.,19,note; llincks,iW?/~.564.

PEDICELLINI'D^E.— A family of Po-
lyzoa, containing the single geuus Pedi-

CELLINA.

PEDICI'NUS, Gerv.— A genus of Pedi-
culida); with the antenntc 3-jointed, the
fourth and fifth being fused with tlio third,
the head elongate ; the legs all scansovial ;
abdomen broad. On Quadrumana. (Mt^g-
nin, Paras. 70.)

PEDIC'UEUS, L.— A genus of Anoplu-
rous Insects, of the family Pediculida?.

Char. Legs all scansorial or prehensile;
thorax large, not constricted from the abdo-
men, which has seven segments ; antenute
five-jointed ; mouth with a fleshy rostrum.

The species are human lice. The colour
varies according to that of the skin of the
pe(jple they inhabit ; being darker in the
dark ti-ibes.

Rostrum retractile, concealed beneath the
head, furmiug a soft tubular sheath dilated
at. the end, where it is furnished with a
double row of hooks, and containing a horny
tube formed of four setae.

P. capitis. Ashy-white, thorax elon-
gated, quadrate, abdiimen ovate, laterally
lobed, segments blackish at the margin.
Length of male, l-lO" ; of female, 1-8",

P. vestimenti, bodv or clothes' louse
(PI. 35. fig. 3). Dirty white, elongato-
ovate ; head much produced ; thorax con-
tracted in front; abdomen with the seg-
ments indistinctly indicated. Length about
1-8".

P. tahescentium, distemper-louse. Pale
yellow ; head rounded ; antennae long ;
thorax large and quadrate ; abdomen large,
the segments intimately united. Doubtfully
British.

The extraordinary annoyance stated to
have been produced by these vermin, has
arisen from the -want of washing and puri-
fication of woollen garments.

See Phthirius.

BiBL. Dennv, Anoplur. ; Murray, Ec.
Ent. 391 ; Schieidte, Ann. N. H. 1860, xvii.
213; Megnin, Paras. 74: Piaget, Pedicul.
18b0.

PELARGO'NIUM. See Pollen, Ra-
PHIDES, and Hairs.

PELECTDA, J)\\].,=Loxodes, CI. & L.

P. rostrum (PI. 31. fig. 39) = Zo.rof?es

PELL^'A, Lk.— A genus of Pterideae

(Polypodiaceous Ferns). Many species,
tropical. (Hooker, Syn. 144.)

PEL'LIA. — A genus of Pelliea; (froudose
Hepaticae). P. epiphylla (fig. 550) is not
uncommon in damp shady places, by springs
and wells, where it grows rapidly. Its
pedicels are silvery-white, the capsules pale
brown ; and when the ^■alves are fully ex-
panded, the elaters form an elegant tuft
in the middle. The character of the frond
varies somewhat according to the degree of
moisture of the habitat. The forms called
lonyifolia nnd fiirciycra are now considered
to constitute a distinct species, P. calycina.

BiBL. Hooker, Br. Jung. pi. 47 ; Br.

PELLIE.E.

[ .583 ]

PELON^A.

Fig. 55G.

Pellia epiphylla.
Magnifled 2 diameters.

Flora, ii. pt. 1. 130 ; Endlicher, Gen. Plant.
Svjyp. i. Nos. 472-5 ; Ekart, Syn. Jung. G3,
pis. 7 & 13 ; Eng. Bot. Siqyp. pi. 2873.

PELLIE'^.— A tribe of Liverworts or
Hepaticfe, nearly allied to the Juugerman-
niese in the character of the fructification,
hut having a lobed thalloid frond, traversed
bv a mid nerve, from which the fruit-stalks

arise.

British Genera.

Blyttia. Fructification emerging fi'om the
end of tlie rib below the apex of the frond,
at length dorsal. Perichsete 4-5-pnrted ;
lobes torn. Perigone herbaceous, tubular,
the mouth denticulated. Archegones eight
to twenty. Epigone persistent, torn at the
summit. Sporange 4-valved. Antheridia
dorsal, placed on the rib, covered by dentate
incumbent leaflets.

PetalophyJlum. Fructification from the
upper sui-face of the plaited frond. Peri-
chtete broad, bell-shaped and toothed.
Perigone wantLug. Epigone concealed in
the perichsete. Sporange bursting into
iiTegiilar lacinise. Elaters often branched.

Fossombronia. Fructification emerging
from the end of the rib below the apex of
the frond, at length dorsal. Perichsete
obconic bell-shaped, the mouth crenate or
dentate. Perigone wanting. Archegones
few. Epigone persistent, torn at the sum-

mit. Sporange circumscissile. Antheridia
dorsal, situated on the rib, naked.

Metzyeria. Fructilication emerging from
the ventral side of the midrib of the frond,
Pcrichsete ventricose, at length bipartite.
Perigone none. Archegones few. Epigone
persistent, torn at the summit. Sporange

four-valved
on the rib,
leaflets.

Aneura.
the ventral
frond. Perichaete
Perio-one wanting

Antheridia ventral, placed
covered by incumbent dentate

Fructification
side, near the

emerging

from

of the

short, lobed or torn.

Archegones few. Epi-

gone persistent, torn at the summit. Spo-
range four-valved. iintheridia immersed
in the back of special lobes of the frond.

Pellia. Fructification emerging from the
dorsal side of the frond. Perichsete short,
somewhat cup-shaped, the mouth lacero-
dentate. Perigone wanting. Archegones
several. Epigone membranous, accompanied
by a few sterile archegones, at first, at the
lower part. Sporange fom-valved. An-
theridia immersed in the surface of the
frond.

Blasia. Fructification at first immersed
in the rib of the frond, then emerging fi'om
the apex. Peiichgete and perigone wanting.
Epigone membranous, with few sterile
archegones, at first, scattered toward the
lowest part. Sporange four-valved. An-
theridia immersed in the rib of the thallus,
more prominent below, and covered by
little dentate scales.

Taryionia. Fructification sessile, inferior,
solitary and terminal to the frond. Perichsete
two-valved, splitting vertically. Perigone
wanting. Epigone delicate, persistent, in-
vesting the sporange until maturity, some-
times evanescent above. Sporange biu'sting
by an irregular slit, or into fragments. An-
theridia immersed in the rib of the frond
below, covered by papiUfe.

PELOMYX'A, Greef .— A genus of Amoe-
bpea (Rhizopoda).

This freshwater organism forms large
brown amoeboid masses, with lobose hyaline
pseudopodia. The ground-substance con-
tains nuclei, hyaline homogeneous highly
refractive, and delicate rod-like bodies. It
gives lise to swarms of minute Amoebae,
which become developed into flagellate free-
swimming organisms.

BiBL. Greef, Schultse's Archiv, 1873 ;
Qu. Mic. Jn. 1874, 97.

PELON^'A, Forbes.— A genus of Tu-
nicate Mollusca, of the family Pelongeadae.

PELOPS.

[ -"^84 ]

PENICILLIUM.

Char. Unattached ; feet cylindrical ; ori-
fices ^^-itll0^lt rays, on two equal approximate
warty eminences at tlie anterior end. They
live buried in mud. Two species^

P. corrugata. Test deep brown, much
elongated, rudely wrinkled transversely.

P. (glabra. Test greenish yellow, smooth,
pilose, shorter than the last. See Tuni-

CATA.

BiBL. Forbes and Hanley, Br. Moll. i.
43.

PE'LOPS, Koch (Aearina). — Differs
from Oribaia in the hau'S on the vertex
being flat or spatula-shaped. (Murray, Ec.
Ent. 218; Michael, Jn. itfjc/Soc. 1879, 237.)

PEI.OPSI'NA, Brady,— A genus of Are-
naceous Foraminifera, one- or many-cham-
bered ; Willis thick, composed of mud, with
a long cliitinous neck. Living, South Seas.
(Brady, Qti. M. Jn. 1879.)

PELTIDEA, noto., = Species of Pel-
TiGERA and Sticta.

PELTID'IUM = Alteutha.

PELTIG'ERA, Willd. — A genus of
Parmeliaceous Lichens, characterized by a
foliaceous, usually leathery thallus, with
woolly veins beneath ; the suborbicular
shield-like apothecia arising on the upper
sides of the lobules.

P. canina, a large Lichen, is extremely
common on the ground among moss in
woods. Two or three nearly allied species
are separated from this by most authors,
but wnth questionable propriety. Three or
four others are subalpine.

BiBL. Hook. Br. Fl. ii. pt. 1. 218; Eny.
Bot. 2229 ; Leio-hton, Lich. Flor. 101.

PENEROP'LIS, Lamk.— A genus of
Porcellaneous Foraminifera,

Broad, complanate, and ear-shaped (P.
jjertusns, PL 23. fig. 11), or narrow, subcy-
lindric, and crosier-like (Spiroluia) (S.
austriaca, PI. 23. fig. 12) ; striated. The
primordial double chamber is succeeded by
curved chambers in one direction ; and as
these vary in transverse extent, sometimes
to even three fourths of a cii'cle, the shell
takes different shapes. The aperture is
single and lobulate in the early chambers ;
cribrate in the narrow, branched in the
nautiloid forms {Dendritina) ; and divided
into rows of lioles, often tubular, in the
outspread varieties. Living in the Medi-
terranean and warm seas only ; fossil in the
Tertiaries.

BiBL. Williamson, Rec. For. 45 ; Parker
and Jones, Ann. N. H, 3. v. 179 ; Car-
penter, Phil. Tr. 1859, 2 ; Foram. 84.

PENICIL'LIUM, Link.— A genus of Mu-
cedines (Hypliomycetous Fungi), of which
the species P. f/laueitni is at once one of the
most frequent and the most puzzling plants
of the class. This fungus is the commonest
of the constituents of the greenish or bluish
mould formed on decaying vegetable sub-
stances of all kinds, especially on semifluid
or liquid matters. On the surface of liquids
it forms a kind of dense pasty crust, slimy
on , the lower surface, and coloured and
pidverulent (bearing spores) above, ^^'hen
the upper fertile layer is examined under
the microscope, it is found to consist of
pedicels terminating in a repeatedly but
shortly bifurcated pencil, each ultimate
branch of which bears a moniliform row of
spores. The ramification of the pedicels is
not distinctly represented in fig. 557 ; but the
appearance of the spores is characteristic ;
and the ramifications of the sporophores are
scarcely perceptible in examples growing on
dryish substances. The mode of attachment
of the spores is shown in figs. 15 and 16 of
PI. 26. The mycelium consists of inter-
woven articulated filaments, most exten-
sively ramified. The spores appear whitish,
yellowish, gi-eenish, or bluish, according to
age : under the microscope they appear
opaque Avhen mature.

So far there is little difli cully about the
history of these plants ; and if the spores of
the above form are sown on a glass slide,
kept moist with an organic
liquid, they will germinate
and v,imify, and under fa-
vom-able circumstances bear
thin peniciUate tufts of spores
at points which emerge from
the mitrient liquid. But
this same fructification of
P. f/laticum presents itself
invariably under certain cir-
cumstances associated with
the vinegar-plant and the
yeast-plant, toward tJie close
of the ordinary development
of these fungi. In common
with most observers, we find
that the exhaustion of the
saccharine matrix of the
vinegar-plant is 1 olio wed in
all cases by the apjiearance
of crusts of Penicillium-
mould on the upper surface,
whence it woidd appear that
the vinegar-plant was only the mycelium of
Fenicillium. It was asserted, moreover,

Fig. 557.

Penicillium.

A fertile plume
with pencils of
spores.

Magnified 150
diameters.

PENICILLIUM.

[ 585 ]

rEi»rEi{.

many yeai-s ago, by Tiirpin, that P. (//(iiicitm i
is the last term ot' the growth both of the
true yeast-phiut {'Tonila Cerevidce) and of
the milk-yeast {Oidium lactis). We have
found the' gelatinous crusts of the vinegar-
plant to contain structures which represent
Toruki aud Oidium, and to grow like them ;
and we have also observed, iu repeated ex-
periments, that beer allowed to stand until
sour, at tir^t appears clothed with a whitish
mealy collection of minute vesicles, repre-
senting the ultimate stage of Torida, aud
subsec^uently this gradually gave place to
gelatinous matter, which at length covered
the whole surface with a tough him, and
fruited as Penicillium glaucum. Hence it
would appear that the yeast-fungus also
is merely a \egetative form of Fenicillium
developed under pecuhar conditions. This,
however, has been actually proved h\
Berkeley and Iloffiuan (see '' Yeast," in
Black's ' Encyclopedia of Agriculture').
More is said on this point imder Vixkc4AB-
Plant and Yeast.

One of the species has become famous on
account of its extremely rapid occurrence
in Paris on the " pain de munition," where
the spores must have undergone a degree of
heat equal to that of boiling water.

Several species are enumerated ; and we
have given under the separate head of
CoREMiUM a form which is merely a con-
fluent growth of Penicilliuni, producing a
compound pedicel.

P. gJmicum, txrev. Mycelial filaments
form a crust-like web, spores green or
bluish. GreviUe, .b'c. Crypt. Fl. pi. 58. flg. 1.
P. crustaceum, Fries. Extremely com-
mon.

P. candidian, Link. Mycelial filaments
woven together, spores white. (Distinct ?)

P. sparsum, Grev. Mycelium lax, spores
white. Sc. Crypt. Fl. pi. 58. flg. 2. Per-
haps not different from the last.

P. fasciculatum, Sommer. Mycelium
scarcely developed filaments aU fertile,
trifid at the apex, spores glaucescent.

P. subtile, Berk. Extremely minute, my-
celium creeping, fertile filaments erect, sim-
ple or ternate : chains of spores few, spores
broadly elliptical. Ann. N. H. \i. pi. 14.
fig. 25.

P. roseum, Link. Mycelium effused ;
fertile filaments slightly branched, spores
rose-colom\

One species (P. curtipes) has been found
in amber.

BiBL. Berk. hook. Br. Flor. ii. pt. 2.

Cells
trans-
Length

844; Ann. N. 11. i. 202, vi. 437, 2. vii. 102;
Greville, loc. cit. ; Fries, ISyst. Myc. iii. 407 ;
Sum. Veyet. 489. See also Yeast and
Vinegar-Plant.

PE'NIUM, J5reb.— A genus of Desmidi-
aceiB.

Char. Cells single, entire, elongated,
straight, and slightly or not at all constrict-
ed in the middle.

Sporangia round or quadrangular, smooth,
not spinous.

At each end of the cells is a rounded
space containing moving molecules.
Several British species (Ralfs).
P. Brebissonii (PL 14. fig. 36).
smooth, cylindrical, ends rounded,
verse median baud inconspicuous.
1-640 to 1-400".

Common. Sporangium at first quadrate,
but finally orbicular ; conjugating cells per-
sistent, or remaining permanently attached
to the sporangium.

P. inaryaritaceum (PL 14. fig. :\7 , empty
cell). Cells cylindrical or fusiform, with
rounded truncate ends, and covered with
pearlv granules in longitudinal rows. Length
1-160":

BiBL. Ralfs, Desmid. 148; Archer, Qu,
Mic. Jn. 1864, 179, 1867, 183
Alg. ; Rabenh. Alg. iii. 119.

PENNAT'ULA, Cuv. (Sea-pen). — A
genus of Alcyonaria (Zoophytes).

The spicula form interesting microscopic
objects.

■PENTHALEUS, Koch. — A genus of
Trombidina (Acarina). Somewhat elon-
gate ; anterior legs rather long and slender ;
femora of hind legs thickened. P.hcematopus.
(Koch, Uebers. ; Murrav, Ec. Ent. 121.)

PENTHALO'BES, Uyn:i\,=Meyamerus
ovcdis.

^ PEPLONYS'SUS, Kol. — A genus of
Sarcoptidfe (Acarina). 2 species; yellow-
ish-brown ; on Nycteris and Rkinopoma ;
Egypt. (Kolenati, Sitz. Ak. Wien, 1858,
74 • Murray, Ec. Ent. 323.)

PE FPER. — Black pepper consists of the
benies of Piper- nigrum ; white aud decor-
ticated pepper of the same berries with the
outer part of the coats removed. The cel-
lular tissues of the several lamellae of the
husk, and of the albumen or body of the
seed, are tolerably characteristic (PL 2. fig.
12) , and may be known by their appearance
under the microscope from the fragments of
linseed, mastard, &c. with which peppers
are sometimes adulterated. White pepper
is fraudulently reduced with flour, which

, Hassall,

PERACANTHA,

f 586

PERIGLISHRUS.

may he detected by the starch-gi-auules —
those existing in pepper itself being exceed-
ingly minute particles; the same remark
applies to rice and pea-flour, &c. Exces-
sive quantities of the hiisli-tissue in black
pepper denote that the refuse of the decor-
ticated white peppers has been added. (See
also Cayenne.)

BiBL. Pereira, Mat. Medica ; Plassall,
Food and its Adtdterations, 42.

PERACAN'TIIA, Baird.— A genus of
Entomostraca, of the order Cladocera, and
family Lynceidae.

Char. Side view of shell oval, the lower
and posterior portion with an acute projec-
tion directed backwards and upwards, and,
as well as the upper extremity of the ante-
rior margin, beset with strong hooked
spines ; beak sharp, curved downwards.

P. tnmcata (PI. 19. fig. ol). Superior an-
tennae conical ; inferior short, the anterior
branch with five setfe, one from first, one
from second, and three from last joint ; pos-
terior branch with three setpe from the last
joint only ; intestine convoluted, with one
turn and a half ; ova two ; freshwater.

BiBL. Baird, Bi-it. Enfoin. 136.

PERANE'MA, Duj.— A genus of Flagel-
late Lifusoria, family Eugienia.

Char. Form variable, globular, or inflated
posteriorly and narrowed in front, where it
becomes prolonged into a long flagelli-
form filament; movement slow, uniform,
forwards.

P. (/lobulosa (PI. .31. fig. 59). Body almost
globular, more or less drawn out anteriorly,
with oblique wrinkles on the surface ;
freshwater; length 1-1400".

BiBL. DujarcL Inf. 353 ; Pritchard, Inf.
545.

PERANE'MA, Don = SPH^ROPTEBis.

PERFORATA, Carpenter. — The Di-
vision of Foraminifera tliat possess a vitre-
ous or hyaline shell perforated by tubular
openings for the exit of pseudopodia.

BiBL. Carpenter, Infrod. For am. 149.

PERICH.il'NA, Fr.— A genus of Myxo-
mycetes, consisting of little rounded mem-
branous sacs of brownish or yellowish colour,
generally splitting all round (transversely),
and discharging yellow spores and (few)
free and elastic filaments. The commonest
(P. popidina), yt>ll(n\'ish and about as large
as a mustard-seed, occurs on fallen poplar
trees ; two others occur in fir-plantations.

BiBL. Ikn-kelev, Hook. Br. Fl. ii. pt. 2.
321; Fries, Syst. Myc. 190; Sum. Veget.
459 ; Greville, Crypt. Flora, 252.

PERICO'NIA, Tode.— A genus of De-
matiei (Hyphomycetous Fungi), character-
ized by a stem composed of fascicidate com-
pacted threads. Head globose ; spores fixed
on the free apices of the threads. It is
analogous to Pachnocyhe. Tulasne states
that it is merely a conidiiferous form of
some Sphcsria, Two species occur in this
country.

P. ylaucocephala, Cd. ; on decayed linen.

P. calicioides, B. ; on dead herbaceous
stems.

BiBL. Fries, Summa Veg. 1G8 ; Berk.
& Broome, Ann. N. H. 2. v. 165 ; Tulasne,
Ann. Sc. Nat. 4. v. 109 ; Cooke, Handb.
565.

PERIDERM. See B.4Iik.

PERIDER'MIUM, Lk. — A genus of
ITredinei (Hypodermous Fungi), distin-
guished from ^ciDiUM by the sac-like
perithecium bursting irregularty, as if by a
circumscissile dehiscence. The type of this
genus is P. (jFcid.) Pint, found on the
leaves and bark of Scotch Firs. The spores
are covered with very numerous small
tubercles. See Ubedinei.

BiBL. Berk. Br. Fl. ii. pt. 2. 374; Tu-
lasne, Ann. Sc. Nat. 4 ser. ii. 176, pi. 10 ;
De Bary, Brandjnlze, 1853, 72.

PERIDINI'NA. — An Order of Cilio-
flagellate Infusoria (see p. 422).

PERIDINTUM.— A genus of Peridinina
(Cilio-flagellate Infusoria).

Char. Body with a transverse groove, the
two portions of -the facetted lorica uearlj-
equal.

Those species with a horn-hke process,
are sometimes separated as Ceratlum.

P.ftiscum (PI. 31. fig. 11). Brown, not
luminous, carapace ovate, slightly com-
pressed, smooth, acute in front, rounded
behind; freshwater; 1. 1-430 to 1-290".

P. (C.) tripos (PI. 31. fig. 12). Yellowish,
splendidly phosphorescent ; carapace urceo-
late, broadly concave, mouth with three
horns, two very long, frontal, and recm'ved,
the third posterior and straight ; marine ;
length 1-140".

Several other species. See Glenodi-
Niujr.

BiBL. Ehr. Inf 262; Duj. Inf. 374;
Allman, Micr. Jn. iii. 24 ; Clap, et Lach.
Etmles, 403 ; Clark, Ann. N. H. 1865, xvi.
270 ; Kent, Inf 447.

PERIGLISCHRUS, Koch. SeePxEROP-

TUS.

Tlie species adhere by the margin of the
body aU round.

PEETGONIMUS.

[

PERISPOEIUM.

PERIGON'IMUS, Sars.— A genus of
AtractylidiV (ITydiMid Zoopliytes).

DiiR'vs Iroiu Atractylis in the simple fixed
spove-sacs being medusiforni.

On other marine zoophytes, shells, &c.

Biiii,. St. \\'ri!,'lit, rr. Boy. Sor. Edin.
1S57, 18^58; Ann. N. II. 1801, 1;J0; Alder,
Trans. Ti/nes. F. C. v. 230 ; AUman, Ann.
N. IT. 1863,1804; Hincks, Ili/d. Zooph. S9.

P]':rtrOLA, Fries.-i'. Ummdosa, Fr.,
described as a Sclerotioid Fur,o:us, is an
obscure, irregular, tleshy body, with a white
villous surface, foimd growing on potatoes.
It is probably the early form of some unas-
certained species of fungus. This was cha-
racteristic of those forms of potato-rot
which were known before the introduction
of tlie Peronospora.

PEPtlP'TERA, Ehr.— A genus of Dia-
tomaceoe.

Char. Frustules single, compressed ; valves
dissimilar, one being simply turgid, the
otlier winged or furnished with horns ;
horns sometimes branched and attached to
the extreme margin. Fossil.

Valves not areolar nor punctate under
ordinary illumination. America and Ber-
muda.

P. cMaymdophora (PL 50. fig. 41) ; P. te-
tracladia (W. 18. fig. 6G) ; P. capra (PL 18.
fig. 07).

BiBL. Ehrenb. Ber. Berl. Ak. 1844, 263 ;
Kiitz. Sp. Alq. 25.

PEPtlSPIRA, St.— A genus of Holotri-
chous Infusoria. Free, ovate; mouth an-
terior ; oral cilia extending spirally towards
the posterior end.

P. ovum ; green, = Iloplophryu ovum ?
(Kent, /«/". 511.)

PERISPOPJA'CEL— A famil}; of Asco-
mycetous Fungi, mostly epiph}i;ic and of
smaU size, characterized by producing floc-
cose commdn receptacles (mostly) radiating
from a point, forming patches upon leaves,
Sec, in the centre of which are developed
somewhat globular perithecia of obscure
cellular structure, persistent, bursting at
the summit, filled densely with subgelatin-
ous, scarcely diftluent gelatine ; sporidia
produced in asci, subsequently often eff"used,
simple, free, and mixed with the gelatine
in the centre of the peritheciuiu. The m}'-
celia of these plants, bearing conidial struc-
tures, have been described as distinct fungi,
for example those of Erysiphe as Oidia,
&c. See Eeysiphe. Eitiotium probably
belongs here. British Genera :

Lasiobotrys. Perithecium fleshy-horny.

globular, naked, collapsing at the sum-
mit.

Capnodium. Perithecium fleshy, clavate,
double (the outer cellular, interior hya-
line), mucilaginous, opening by a fringed
mouth ; asci containing about six spores in
two rows.

Erysiphe. Perithecium membranous,
closed at first, afterwards open, supported
on a persistent radiating mycelium formed
of continuous filaments bifid at their ends.
Asci one to eight, paraphyses none ; spores
definite, ovate.

Pcrisporium. Perithecium superficial,
at length bursting irregularly. Asci club-
shaped, not mixed with paraphyses. Spores
numerous, ovate.

Chcetomium. Perithecium superfcial,
finally open at the mouth, clothed externally
with opaque hairs. Asci clavate, mixed with
paraphyses. Spores simple, ovate.

Ascotricha. Perithecium thin, at length
bursthig, clothed with dark, subpellucid,
even, obscurely-jointed hairs. Spores sim-
ple, C(mtained in linear asci. Superficial,
at length free or resting on the investing
thallus, black.

Orhicida, Cooke. Perithecium seated on
a distinct mycelium, reticulated. Ostiolum
obsolete ; sporidia subglobose ; paraphj-ses
simple or branched.

PERISPO'RIUM, Fr.— A genus of Pe-
risporiacei (Ascomycetous Fungi), consisting
of minute, globular, free, punctiform sacs,
with fleshy or waxy walls, seated on an
obscure thallus, growing on leaves or stalks;
finally biu-sting and collapsing. The spores
are produced in large numbers in swollen
clavate asci (figs. 558, 559), which are un-
accompanied by paraphyses.

Fio-. 558.

Fig. 659.

Pcrisporium disscminatum.

Fig. .358. A perithecium in vertical section. Magni-
flcfi 100 diameters.
Fig. 559. An ascus detached. Magnified 300 diams.

BiBL. Fries, Sum. Veq. 404 ; Syst. 3Iyc;
iii. 248 ; Berk. Ann. N. H. vi. 432.

PERISTEPHANIA.

[ 588 ]

PETALOPUS.

PEPtlSTEPHA'NIA, Ehr.— A genus of
Diatumaceae, closely allied to Stephano-
discus, differing, however, in having a
parallel (and non-radiate) arrangement of
the granules ; and also to Sysfephania,
Avhifh differs only in having iutramarginal
teeth. P. eutycha in deep Atlantic sound-
ings ; P. lineata in guano.

BiBL. Pritchard, Infiis. 824.

PERITHE'CIUM.— The name applied to
the special envelope, mostly of different
structure from the rest of the thaUus or the
receptacle, enclosing the nucleus of the
Angiocarpous Lichens and the Pyreuomy-
cetous Fungi.

PERITH'YPtA, Ehr.— A doubtful genus
of Diatomacese. Probably closety allied to
CoscinodiscKS. 2 species from the Ganges.

BiBL. Pritchard, Infus. 842.

PERITIIO'MUS, St.— A doubtful genus
of Infusoria. (Kent, Inf. 759.)

PERIZO'NIUM, Cohn et Jan.- A genus
of Diatiimacete.

Char. Frustules navicular, free, en-
circled with thick linear zones,

P. Braimu (PI. 51. fig. 42), fresh-
water.

BiBL. Rabenh. Alg. i. 228.

PERO'NIUM, Cohn.— A genus of Mona-
dina allied to Ant/tojjhi/sa. It is parasitic
on the spores of I'i/idaria, and consists of
a delicate, colourless fibre surmounted by a
globular head which resolves into numerous
narrow cells of a monadiform character.

BiBL. Cohn, Entivick. 158 ; Pritchard,
Inf. 501.

■PERONOS'PORA, Ung. See Botrytis,
& Smith, M. M. Jn. x\\. 120.

PEROPHORA, AViegm.— A genus of
Tunicate MoUusca, family Claveliuidfe.

Cliar. Individuals stalked, roundish, com-
pressed ; thorax not marked with granular
lines.

P. Listeri. Occurs attached to sea-weeds.
Very transparent, appearing like little specks
of jelly dotted with orange and brown.

BiBL. Forbes and Ilanley, Br. MoU. i.
28

PERTUSA'RIA, DC— A genus of
Lichenaceous Lichens, having an adnate,
uniform tliallus, spreading over bark, rucks,
(fcc, and bearing wart-like apothecia, finally
exhibiting a depressed pore m their centre,
leading to the one or several cells containing
the thec£e. P. communis is very common
on trees.

BiBL. Hook, Br. Fl. ii. pt, 1, 1(J4; Enyl.
Bot. pi, 677 ; Leighton, Lich. Flora, 226.

PESTALOZ'ZIA, De Not.— A genus of
Melanconiei (Stylosporous Fungi), with
septate spores seated on a long pedicel, and
crested at the apex (fig. 711). Three species
occur in this country, P. Guepini is some-
times very destructive to Camellias. They
are beautiful microscopic objects.

See fig, under Stylospoees.

BiBL. Berk. Otitl. 324 ; Cooke, Handb.
471.

PETALOxM'OXAS, St.- A genus of Fla-
gellate Infusoria. Free, ovate, depressed,
Hagellum single, long, mouth at the base
of the flageUum.

P. abscissa=Cyclidmm ahs., Duj,; other
species ; freshwater, (Stein, Inf. iii, j Kent,
Inf. 371.)
^ PETALONE'MA, Berk. (Arf/irosiphon,
Kiitz.). — A genus of Oscillatoriacete (Con-
fervoid Alga;), with a remarkable mode of
growth. The filaments are branched and
cylindrical, with an evident terete, gelatinous,
duplicate sheath (PI. 8. fig, 21). The inner
is thin and follows the filament; the outer
presents oblique striae indicating the inter-
position of lengths of the outer sheaths one
inside another, like a series of nested funnels
or conical cups. This appearance is pro-
duced by the bursting and expansion of
each length of the sheath at the apex alone,
to make room for the growth of the new
cells of the filaments formed at the apex.
This structm-e is analogous to that occurring
in Ueococcus, where each parent-cell
membrane bursts -at one side only to allow
the new one to emerge, thus at length
forming a jointed pedicel. The edges of the
funnels of Petcdonema sometimes become de-
composed into curled filamentous processes.

The filaments of P. alatum are green and
striated, about 1-3000" in diameter ; the
inner sheath is yellowish, the outer colour-
less and 1-400'' in diameter, ' It forms a
brownish stratiun on rocks and stones,

BiBL, Berkelev, Gleanings, 23, pi, 7 ;
Greville, Crypt. Fl. pi. 222; Hassall, Fr.
Ah). 237, ph 68 ; Kiitz. Spec. Aly. 311 ; Tub.
Phyc. ii. '2S ; Al, Braun, Pejtiren., Bay Soc.
1853, 178 ; Rabenh. Ah/, ii", 265,

PETALOPHYL'LUM, Wilson,— A ge-
nus of PeUieaj (frondosa Ilepaticaj), P.
Italfsii is an elegant little Liverwort with
the frond plaited or lamellated in rays fi'om
the orisrin of the fruit,

BiBL, Enql. Bot. Stipp. pi. 2874.

PETAL'OPUS, Clap, et Lach,— A genus
of Amcebaea (Rhizopoda). Pseudopodia
filiform, arising from one point of the sur-

PETALOTRICHA.

[ 589 ]

PEZIZA.

face, but expanding at the end into a delicate
film. The film and pseudopodia become
globular before retraction.

P. diffliiens (PI. 52. fig. 16), freshwater.

BiBL. Claparede et Lachniann, Etndes,
44i>.

PETALOT'RICHA, K.— A genus of
marine Peritrichous Infusoria. Free, at-
tached to tlie base of a horny carapace by
a peduncle ; anteriorly a ring of ciliated
petaloid segments. 2 species. (Kent, Inf.
627.)

PETALS.— The petals of Flowering
Plants afford many interesting microscopic
objects, in the epidermis, glandular and
other hairs, the colour-cells, and the veins
composed of spiral vessels. Entire petals
of small size and delicate character form
good objects when dried and mounted in
Canada balsam. Those of the smaller
Caiyophyllacese, the ligulate corollas of
Composita?, Szc, are well suited for this.
The larger kinds are studied by means of
sections, like Leaves.

PETROBIA, 'Muvv.,= Tefrani/chu.i oris-
fatus.

PETRO'BIUS, Leach.— A genus of Li-
sects, of the order Thysauura, and family
Lepismenas.

P. }nan'ti}nus has a general resemblance
to Lepisma saccharina ; but it exercises a
leaping movement. The antennee are longer
than the body ; of the setse at the tail, the
middle one is longest. The insect is of a
blackish-brown colour, and is covered with
scales ; the legs ai-e yellowish , and the caudal
setae ringed Avith white ; the abdomen is
furnished Avill gill-like processes.

It is foimd upon the rocky- sea-coast.

The scales have been used as test-objects.

BiBL. Gervais, Walckenaer's Apt. iii.
447; Guerin, Iconogr. Ins. pi. 2. tig. If;
and Ami. Sc. Kat. 2 ser. v. 374.

PETRONE'MA, Thwaites.— A genus of
Oscillatoriacefe (Confervoid Algae). P.
frvticuhsa grows as a frustulose olive-
brown crust on limestone rocks (not marine),
forming little hemispherical masses ; the
sheaths are thick and cartilaginous, brown
above but colourless at the tips, the proto-
plasm dull green.

BiBL. Engl Bot. Supp. pi. 2959.

PEYER'S GLANDS. See Lctestine.s
(p. 440).

PEYSSONELIA, Dene.— A genus of
C.i-j-ptonemiacese (Florideous Algae), con-
sisting of small plants with a depressed
lobed ihallus (fig. 560), growing over stones.

shells, &c., attached by the whole under
surface, which produces jointed radical hairs
(fig. 661), especially at the thin margins.

Fig. 560.

Thallus. Nat. size.

Fig. 561.

Peyssonelia squamosa.
Vertical section of a portion through two warts.

Magnified 25 diameters.

The thallus is composed of several rows of
compact parenchymatous cells, and bears
on the conceutrically-marlved surface warts
composed of radiating rows of cells, among
which occur crucially-divided tetraspores.
P. Dubyi is not uncommon on British
shores ; it is 1 to 2" in diameter, roundish
at first, ultimately irregularly lobed, and
dull brownish. Thuret has observed an-
theridia on distinct plants of P. squamosa, a
Mediterranean form ; they are jointed fila-
ments collected into wart-like bodies, like
those containing the tetraspores.

BiBL. Harvev, Mar. Ah/. 144, pi. 14 D;
P7ii/c. Brit. pi. '71 ; Thuret, Ann. Sc. Nat.
4 ser. iii. 23, pi. 4.

PEZI'ZA, Dill.— A genus (.f HelveUacei
( Ascomycetous . Fungi), containing nume-
rous species, a large number of Avhich grow
upon dead wood, on the ground, among
leaves kc, many brightly coloured. They
are at first closed sacs, which burst at the
summit, and spread out to form a kind of
cup containing asci and paraphyses. Thus
they belong to the Discomycetes of some
authors.

Tulasne has shown that some of the
Pezizce have a secondarv fructification con-

PHACELOMONAS.

[ 590 ]

PIIACOPSIS.

si.sling- of sti/lospoies ; these have beeu de-
scribed as species of Dacnjmyces. Other
species also produce spermatia ; but this was

Fig. 562.

Fig. 563.

Fig. 564.

Peziza furfuracea. Small variety.
Magnified 5 diameters.

long since suspected by Fries. (See PI. 27.

%• 18.)

BiBL. Berk. Br. Fl. ii. pt. 2. 186 ; Fries,
Stimma Veq. 348 ; Tulasne, Ann. Sc. Nat.
3 ser. XX. 167 ; Currev, Jn. Mic. Sc. v. 124.

PHACELOM'ONAS, Ehr.— A doubtfiU
genus of Infusoria.

Char. Tail-like process absent; a red
(eye-) spot present ; mouth teruiinal, trun-
cate, furnished with eight to ten anterior
long cilia or flagelliform filaments, vacuoles
numerous.

P. pulvisculus. Body oblong, subconical,
attenuate posteriorly, bright green: aqua-
tic ; length 1-1150". Occm-s in myriads m
pools. Perhaps zoospores of GEdogonium.

BiBL. Ehr. Inf. 28 ; Pritch. Inf. 494.

PHACIDIA'CEL— A family of small
Ascomycetous Fungi, mostly growing in
large numbers on the half-decayed woody
parts of plants, or on the ground ; consist-
ing usually of davlc-coloured indurated or
leathery bodies, solitary or connate, or
seated on a common base, closed at first
and containing a soft nucleus; the outer
case (penthecmm) subsequently opening
widely, and presenting a cavity lined with
asci containing spores.

Tlie history of development of these plants
is still obscure ; for many of them are con-
nected with certain of the Coniomycetes as
diHerent staa-es of one and the same plant.
We describe the genera according to the
existing classifications, noting the new facts
rehUing to these metamorphic phenomena
in the articles on the particular genera.

British Genera.

* Perithecium open, marf/inal, closed bij a

lid or veil.

Patellaria. Perithecium patelliform, mar-

o-ined, open, covered with a thin veil con-

fiueiit with the nucleus. Disk at length

pulverident, the annulate asci breaking out.

Ti/nipanis. Perithecium cup-shaped, mar-
gined, open, covered by a thin, evanescent
veil. Disk fixed in the receptacle (proper
stratum), at length dissolved. Asci filiform,
fixed.

** Perithecium (e.rcipidum) at length open,
connate roitli the Jloccose receptacle.
Nucleus discoid, ascigerous, placed on
the receptacle.

Cenangimn. Perithecium entire, leathery-
horny, opening by a connivent mouth, di-
stinct from the discigerous stratum. Asci
filiform, persistent, expelling the separate
spores -ndth violence.

*** Perithecium entire, dehiscing hg closely
connivent slits.
Lophium. Perithecium subsessile, elon-
gated, compressed, bursting by a longitudinal
slit. Asci erect, fixed, cyhndrical, persistent ;
sporidia simple, rounded. Thallus crus-
taceous or imperceptible.

-**** Peritliecium someiohat dimidiate, at
length open, nucleus naked.

Rhgtisma. Perithecium innate, of irregular
form, opening by fi-agments breaking ofl'
into a tiexuous slit ; nucleus placeutiform,
persistent. Asci erect, fixed ; paraphyses
stalked.

Phacidium. Peritheciumroundish, simple,
bursting with several teeth at the summit ;
nucleus disk-shaped, in some degree per-
sistent. Asci erect, fixed; paraphyses
stalked.

Ilysteriuin. Perithecium sessile, oval or
elongated, with a longitudinal slit at first
closed, afterwards gaping open ; nucleus
linear, somewhat persistent. Asci erect,
fixed ; paraphyses stalked.

LahreJla. Perithecium innate, bursting by
a longitudinal slit ; asci sliort, broad and
obtuse above, attenuated below, mixed with
short flexuose paraphyses; spores few, ovate-
oblong, occasionally contracted or septate in
the middle.

PHACIDIUM, Fr.— A genus of Phaci-
diacei (Asconwcetous Fimgi), containing
many species growing on dead leaves,
branches, &c. Some of them are common,
as P. dentatum, on oak-leaves.

BiBL. Berk. Br. Fl. ii, pt. 2. 291.

PHACOP'SIS, TuL— A genus of Micro-
lichens, parasitic on the thallus of Evernifc
and Lecaiiorce.

PHACOTUS.

[ 591 ]

rillALINA.

BiBL. Lindsay, Bnt. Lich. 318 ; Qti. Mic. \
Jn. 18G9, 143.

PHACO'TUS, Pert)'.— A genus of Cryp-
tomonadiua.

Char. Body round, biconvex, with two or
fom- filaments. Probably it is one of the
Algfe.

BiBL. Pritchard, Infus. 513.
PHA'CUS, Nitzsch, Buj.— A genus of
Flagellate Infusoria, family Thecamona-
dina.

Char. Body flattened and leaf -like, usu-
ally gTcen, with an anterior red (eye-) spot,
a single flageUiform filament, and covered
with a resisting membranous integument,
prolonged posteriorly like a tail. Fresh-
water.

Dujardin distmguishes this genus from
Euglena, by the constancy of the form of
the body, which varies every moment in
the latter genus.

P. pleuronedes (PI. 31. fig. 62). Body
oval, almost circular, green, with slightly
marked longitudinal furrows, and a tail-like
prolontration a third or fourth of its length ;
length''l-630".

P. longicaudus (PI. 31. figs. 3 & 63). Other
species.

BiBL. Duj. Inf. 334; Archer, Qu. Mic.
Jn. 1871, 99 ;

PH^OSPO'RE^, Thuret. See Fr-

COIDEiE, p. 338.

PHALANSTE'RIUM, Cienk.— A genus
of Choano-Flagellate Infusoria. Bodies
ovate, flagellum single, with a basal collar ;
imbedded in a simple or branched gelatinous
zoary. Two species ; freshwater. (Cien-
kowski, Arch. mikr. An. iv. 428 ; Kent,
Inf. 361.)

■pHAJ.LOIDE'I.— A family of Gastero-
mycetous Fungi, characterized by the pro-
trusion of a large clavate, columnar, stellate
body, or globular, hollow, latticed frame-
work, from the summit of the burst peri-
dium. The basidiospores mast be observed
early here, as thej' fall off and form a deli-
quescent mass upon the hymenium when
the sporange is mature. The fleshy struc-
tiu'e protruded from the dehiscent capsule
is composed of spherical ceUs very loosely
connected ; the peridium, which is very
tough, is composed of closely packed, very
slender, filamentous cells.

BiBL. Berkeley, Ann. N. H. iv. 155 ; Br.
Fl. ii. pt. 2. 226 ; Eossmann, Bot. Zeit. xi.
185.

PHAPtCID'JA, Korb.— A genus of
Micro-lichens found on the apothecia of

Lecanora. Spores 8 ; 2-4-locular, colourless,
linear, or rod-shaped. (Lindsay, Qu. Mic.
Jn. 1869, 343.)

PHASCA'CE^E.— A family of iuopercu-
late Acrocarpous (termiiial-fruited) Mosses,
uunute, gi-egarious or csespitose, with a
simple or branched stem. Leaves oblong,
oval, lanceolate or spathulate, concave, with
a thick cylindrical nerve ; the cells of the
leaves parenchymatous, looser at the base,
by degrees denser towards the summit,
mostly papillose. Capsules mostly obliquely
apicuiate, with spores larger than in most
Mosses, but not so large as in Arciiidjum.
Columella soon vanishing in the smaller
species.

British Genera.

Acaulon. Plants very dwarf, gregarious.
Capsule coutaiued in the closed perichiBte.
Cal}^tra mitre-shaped, dimidiate. In-
florescence monoecious (antheridia on a
distinct branch at the base of the steiu) : or
dioecious (autheridia terminal on a distinct
plant), bud-like.

Phascum. Plants cfespitose. Pericheete
open. Capsule on a longish stalk, and
mostly obliquely apicuiate. Calyptra dimi-
diate. Inflorescence monoecious (autheridia
terminal in a bud on a distinct lateral branch,
or naked and axillary on the fruit-bearing
branch), or dioecious.

PHASCO'LON, Stem.— A genus of
Hypotrichous Infusoria. Free, plano-convex,
broadest in fi'ont; pharynx enclosing a
rod-fascicle. P. vorticeUa ; freshwater ;
length 1-288". • (Kent, Inf. 746.)

PHAS'CUM, L.— A genus of Phascacete
(Acrocarpous Mosses), which is now sub-
divided variously by ditferent authors.
Wilson separates the earlier Ph. alterni-
fulium only, under the name of Archidiitm ;
"foreign authors fiu'ther distinguish between
PiL\scuM, Acaulon, Ephkmertjm, and
AsTOMUJi. Species retained : Ph. crispmn,
cnsjtidatttm, curvicollum, rectum, hryoides.
Ph. cuspidattim is very common on banks,
especiallv on a gravelly soil.

BiBL." Wilson, Bryol. Br. 32; Hooker,
Br. Fl. ii. pt. 1. 6.

PHLALI'NA, Boiy, Ehr.— A genus of
Holotrichous Infuijoria, family Ti-achelina.

Char. Body finely ciliated, ha^-ing a kind
of neck crowned with large cilia; mouth
lateral, below the appendix to the neck ;
freshwater.

P. viridis (PI. .".1. fig. 61). Body oval,
tiask-shaped, gi-eeu, suddenly naiTowed in

PHIALONEMA.

592 ]

PHLYCT.ENA.

front and graduallv behind, neck short
length 1-290".

P. vei'micularis. White.

EiBL. Ehr. Inf. 333 ; Clap, et Lach. Inf.
304; Kent, Lif.' old.

PHIALONE'MA, Stein.— A genns of
Flagellate Infusoria. Free, flask-shaped,
oral aperture everted, with a single lateral
flagellum. P. cyclodomum, surface spirally
ribbed or striate; freshwater; length 1-500".
(Kent, Inf. 373.)

PHILODI'NA, Ehr.— A genus of Rota-
toria, of the family PhilodiniBa.

Char. Eyes two, cervical ; tail-like foot
with horn-like lateral processes.

Ehrenberg describes seven species ; fresh-
water ; in general structure and appearance
closely resembling Rotifer.

P. ~ erythrophtholma (PI. 44. tig. 17).
Colourless, smooth, ej-es round, processes
of foot short; length 1-120 to 1-50".

P. roseola is reddish, the eyes oval ;
P. collaris has a projecting cervical ring ;
P. citrina has the middle of the body yel-
lowish ; P. macrustyla has oblong eyes, and
the foot-processes very long ; in P. megalo-
trocha the eyes are oval, and the rotatory
organs very large ; and in P. aculeata the
body is covered with soft setaceous pro-

BiBL. Ehr. Inf. 498; Pritchard, Inf.
705.

PHILODIN.E'A, Ehr.— A fiimily of
Rotatoria.

Char. No sheath or carapace ; rotatory
organs two, simple, resembling two wheels
when the cilia are in motion.

Body usually cylindrical, or somewhat
spindle-shaped, contractile even so as to
form a ball. In certain states of extension
it sometimes appears pointed in front,
from the presence of a proboscis ; in others
the two ciliated rotatory organs are pro-
truded.

The animals are capable of swimming l^y
means of the cilia, or of creeping like a
leech, the ends of the body being alter-
nately fixed. The tail-like foot is often
furnished with horn-like lateral processes
and terminal toes.

Ehrenberg distinguishes seven genera : —

A. Eye8 absent.

a. Proboscis and horn-like lateral pro- j. Callidina.

cess on the foot present S

p. Proboscis and horn-like processes j.

absent S .

.1. Rotary organ stalked Hydruis.

b. Rotary organ not stalked Typhlina .

B. Eyes present.

Eyes two, frontal.
Foot with horn-lite processes.

Toes two S-oiifer.

Toes three AcUnurus.

Foot without horn-like proces- Ij^onolabis.

ses, but with two toes )

Eyes two, cerTical Philodina.

BiBL. Ehrenberg, Infns. p. 481.

PHILOME'DES, LiUjeborg.— A Cypri-
dinad, with suboval valves, notched in front,
spined behind, pimctate. Upper Hntennge
G-jointed, longer in the male : natatory
branch of lower antennae 9-jointed, secon-
dary branch setose in the female, cheliform
in the male. Eyes small and pale in female,
large and red in male. 1 British species,
rare.

BiBL. Brady, Linn. Tr. xxvi. 377 ; Pr.
Zool. Sac. 187i, 291.

PHILOP'TERUS, Nitzsch.— A genus of
Anoplurous Insects, of the family Philo-
pteridse.

Char. Antennae filiform, five-jointed;
maxillary palpi none ; mouth with strong
toothed mandibles ; tarsi with two claws.

The species are very numerous, and have
been arranged in six subgenera : Docopho-
rus, Nirmus, Goniocotes, Goniodes, Lipeuras,
and Ornifhobius. In some of them there are
two movable oigaus (trabeculae) situated
in front of the antennae.

P. (Docophorus) communis (PI. 35. fig. 5).
Chestnut- coloured, shining, with white
hairs ; head triangular, elongate, anterior
portion much produced ; trabeculae very
large, curved ; posterior femora much incras-
sated and toothed below. Length 1-16".

Parasitic upon the Passeres or Insessores.

BiBL. Deunv, Anoplur. Monogr. 02.
. PHLE'BI.\J Fr.— A genus of Hymeno-
mycetous Fungi, intermediate between
Hydnei and Auricularini. The hymenium
is' soft and pinclied up into crest-like
:sNTiukles or veins, which do not fi^irm di-
stinct pores. Four species are found in this
country, of which two at least are very
prettv when in perfection.

Biuj.. Fv.Si/sf. Myc. i. 426 ; Grev. t. 280;
Hass. ii. t. 44; Berk. Outl. 263; Cooke,
IlaiuJh. 305.

PIlLOEM.~The liber-portion of the
fibro-vascular bundles of stems.

PHLYCTyE'NA, Desmaz.— A genus of
Sphajronemei (Stylosporous Fungi), nearly
related to Sepforia, difiering in the absence
of a proper peritliecium. P. vayabunda has
been found in Britain.

BiBL. Berk, and Broome, Ann. N. H. 2.

PHLYCT^NIA.

[ 593 ]

PHOTOGRAPHY.

xiii. 460; Desmazieres, Ann. Sc. Nat. 8.
viii. 16.
PHLYCTiE'NIA, Kg,— A genus of Dia-

tomaceae.

Char. Frustules those of Naviciila, en-
closed in gelatinous globular cells (masses?).
Marine.

P. minuta. Cells 1-720 to 1-240" in dia-
meter ; length of frustules 1-1200 to 1-600".

P. marUima (Fri(dulia mar., E.).

BrBL. Kiitzing, Sp. Al<j. 96 ; Ehrenberg,
Infiis. 232.

'PHLYCTID'ICJM, Br.— A genus of Uni-
cellular Algae, allied to Chytridium ; con-
sisting of globose or oblong iuoperculate
cells, the orillce simple or slightly produced,
either rooted or not ; gonidia with a single
long cilimn. Several species; in fresh-
water Algse, kc. (Rabenhorst, Fl. Alg.
iii. 278.)

PHLYC'TIS, Wallr.— A genus of Pertu-
sariei (Lichenaceous Lichens). 2 species,
on trees, frequent. (Leightou, Lichen Flora,
237.)

PHO'MA, Fr. — A genus of Sphaeronemei
(Stylosporous Fungi). There are nume-
rous British species, forming small black or
brown pustules upon dead leaves, twigs, kc.
Tulasne regards this genus as formed by
pycnidiiferous states of Sph^ria. P. uvicola
produces the disease called Anthracose on
the vine.

BiBL. Berk. £r. Fl. ii. pt. 2. 285 ; Ann.
X. H. vi. 2G3 ; 2. v. 368, xiii. 459 ; Fries,
Summa Vey. 421 ; Tulasne, Ann. Sc. Nat.
4. V. 115 ; Cornu, Grevillea, vii. 18.

PHO'XOLITE. See Rocks.

PHOR^tllDTUM, Kiitz.— An obscure
genus of Oscillatoriaceee, the filaments
sheathed, forming a membranous layer ;
many species. (Rabenhorst, Fl. Aly. ii.
115.)

PHOR'MIUjNI, Forst.— p. ienax is the
name of the plant yielding New-Zealand
Flax. It is a Monocotyledonous Flowering
Plant belonging to the order Liliacese.

PHOR'ODON, Pass.— A genusof Aphidse.
Two species ; on the hop (Aphis hunmli),
the sloe, and the plum. (Buckton, Aphides,
Rau Soc, i. 165.)

PHOSPHORESCENCE and PHOTO-
GENIC STRUCTURES, see Mio: Diet.
3rd edition, 504 ; and the Bibl. therein.

PHOTOG'RAPHY.— Microscopic ob-
jects may be photographed by the ordinary
methods, especially by the collodion pro-
cess, by arranging the microscope so as to
form the optical part of a camera obscura.

The old solar microscopes are examples of
the principle of such an aiiungement. Mi-
croscopic cameras have been constructed in
which the lens is replaced by a fitting
carrying achromatic object-glasses, with
the rod bearing the stage and illuminating
apparatus, as in the ordinary stands of com-
pound microscopes. A simpler plan for
those who possess a compound instrument
and a camera, is to remove the lens of the
latter and introduce into its place the eye-
end (with the eyepiece removed) of the
compound body, placed in a horizontal posi-
tion ; filling up the crevice all round with
a piece of black velvet or cloth. Another
method (Wenham's) which dispenses with
the camera, is to operate in a room darkened
by a shutter having an orifice through
which the simlight may be reflected by a
mirror placed outside, and received either
directly or condensed by a bull's-eye, on the
object lying on the stage of the microscope
placed horizontally, with the eyepiece re-
moved ; a screen placed at a suitable dis-
tance from the eye-end of the tube receives
the image. In operating with this screen,
the object should be focused on a sheet of
card, and then, the light being shut ofl' by
coveiing the eye-end of the tube, a prepared
paper or collodion plate be substituted ex-
actly in the same place. Means must be
used, by a black cloth or similar contrivance,
to shut ofi" all side light between the orifice
of the shutter and the object-glass. In
this last process, it is possible to obtain
pictures with different parts of the object
not lying in the same plane, by separate
focusing, applying pieces of card suitably
cut to shut oft' the image at difierent parts
as required. With very minute objects and
high powers, the achromatic condenser is
used, as well as the bull's-eye.

It is well known that the correction of
the objectives for perfect vision is not the
best for photographic purposes. With high
powers, as the 1-4" object-glass and upwards,
the difference may be neglected, but with
lower powers, an adjustment is required.
Shadbolt finds it sufiicieut to withdraw the
object-glass a little by the fine movement,
from the object, and gives the following
data for Smith and Beck's object-glass : for
the 4-10", withdraw the objective 1-1000";
for the 2-3", withdraAV it 1-200"; for the
1|", withdraw it 1-150''. Wenham pre-
fers to place a doubly convex lens in the
place of the back stop of the object-glass,
and advises for the 4-10" and 2-3" object-

2q

PHRAGMICOMA.

[ '^94 ]

PHTHIRIUS.

glasses a lens of 5" focus ; for the I5" a lens
of 8" focus.

Microscopic photograplisare test ol^tained
with solar light ; but artificial light has been
used, as that from caniphene or gas for low
powers, the oxyhydrogen light for high
powers, andMaddox has used the magnesium
light. A gi-eat point is to secure clean pre-
parations, with the object sufficiently flat to
allow of being clearly ibcused all over ; this
sets a limit to the utility of the process ;
fm-ther, certain objects in which red and
yellow, or yellowish-brown colours exist, do
not transmit the hght, or only imperfectly.
It will probably be advantageous to bleach
many objects, as, for instance, insects and
their parts, by long maceration in turpen-
tine, sections of dark-coloTired wood by
nitric acid, &c., when they are intended to
be photographed.

The purely photographic manipulation
cannot be given here, but requires the ordi-
nary skill in photography. Lengthened
particulars respecting the application of
photography to the microscope are contained
in the papers referred to below.

BiBL. Ilighley, Qn. Mic. Jn. i. 178, 30o,
and ii. 158 ; Shadbolt, Q^(. Mic. Jn. ii. 1G5;
AVenham, Mic. Tr. 1855, 2. iii. 1 ; Rood,
Qu. Mic. Jn. 1802, 261 ; Hessling and Koll-
mann, Atlas, d. thier. Gewch. 18()2 ; Maddox,
Tr. Mic. Soc. 1863, 9 ; ibid. 1865, 34 ; Jn.
Lond. Photo. Soc. 1864 ; Mn. Mic. Jn. 1869,
27 ; Woodward, ihid. 29, vol. iii. 290; Qu.
Mic. Jn. 1870, 380; Brit. Jn. Photo. 1866;
Moitessier, Photog. Appliquee, 1860 ; Reich-
ardt and Sturenburg, I808, Mon.mik. Phot.;
Benecke, Photo(/r. 1869 ; Hermann, Phot. ;
Gayer, Micro-photor/r. ; M. M. Jn. xv. 258 ;
Frey, Das Mik. ; Beale, How Sfc, and the
notices therein.

PHRAGMICOMA, Dumort.— A genus
of Jungermanniefe (Hepaticse), containing
one British species, P. Mackaii (Jung.
Mackaii, Hook.), occurring
rarely on trees and rocks, espe-
cially on limestone.

BiBL. Hook. lir. Jung. 53 ;
Ekart, Sy?i. Junq. 59, pi. 9.
fig. 72 ; Endlicher, Gen. Plant.
Suppl. i. 472-9.

I'HRAGMID'IUM, Lk.
(Arcgma, Fr.). — A genus of
Uredinei ( Coniomycetous

Fungi), forming rusts very
common on Rosaceous plants.
They appear upon living
leaves, breaking through from

Fig. 565.

beneath the epidermis, and are chiefly dis-
tinguished from PuccixiA by the number
of septa which are contained in the spores
or pseudo.spores. P. bulhosum is common,
forming yellow and brown pulverulent
spots on bramble-leaves (see Aefj^ma).

BiBL. Berk. (Aregma), Br. Fl ii. pt. 2.
358 ; Grev. Sc. Crypt. Flor. pi. 15 ; Tulasne,
Ann. Sc. Nat. 4 S(Sr. ii. 180, pi. 9; De Bary,
Brandpihe, 1853, 49, pi. 4 ; Fries, Sum. Teg.
507; Currev. Q. J. Micr. Sc. v. 117.

PHR A(tM01'RIC'HA 'CE.E.— a family
of Coniomycetes, distinguished from Melan-
coniei by their moniliform chains of spores.
See CoxioMYCKTF.a.

PHRAGMOT'RICHUM, Kze.— A genus

Phragmidiuiii
bulbosum.

Isolated basi-
diiim with four
septate sjioreH.
Mag. lOU diams.

566.

Fi?. 568.

Fig. 567.

Phragmotriehtim Chailletii.

Fig. 566. Scale of a spruce-flr cone, with pustules.

Half nat. size.
Fig. 567. A pustule, magnified 10 diameters.
Fig. 568. Vertical section across a pustule, showing

the chains of sjiores. Magnified lUO diams.

of Phragmotrichacepe (Stylosporous Fungi).
The plants form little tubercles bursting
out from beneath the epidermis, and con-
taining filaments arising from a sottish
fibrous stroma. The filaments (basidia)
are interrupted at intervals with cellular
spores (fig. 568), which ultimately separate.
P. Chailletii grows upon the scales of the
cones of Abies e.vcelsa. Other species grow
on the poplar and maple.

BiBL. Fries, Si/st. Mi/c. iii. 4d'2 ; Sum,
Veq. 474 ; Berk. Crypt. Bot. 327.

PIlTlIlR'irS, Leach.— A genus of
Anophira, family Pediculidae.

Char. Legs of two kinds, anterior pair
formed for walking, pdsteiior pairs for
climbing ; thorax large, not distinctly sepa-
I'ated from the abdomen.

PIIYCOMYCES.

[ 595 ]

niYLLOPirORA.

p. itHfiilnalh (redicuhis pubis). Parasitic
upon mill). Length 1-10 to 1-20".

The ova are firmly fastened to the haira
by ii gliitiiiou.-i pei-ietion ; tliey are urn-
shaped, and furnir^lied witli a lid.

]}iRL. Deuuy, M'>n. Anopl. 8 ; Leach,
Zool. Mine. iii. Go ; Mi^gnin, Paras. 7o.

PHYCOMY'Cf:S, Kze.— A genus of
Mucoiini ( Phycomycetous Fungi), of wliifli
one species, P. nifens, has beeu found in
Britain growing on the walls of oil-cellars
and on grease. It is olive-coloured, dis-
tinguished iVom Miicor chietly by the absence
of a columella, the pyrilbrm peridiole, and
oblong spores; but the entire plants are
much larger and of more solid texture.
The fertile filaments of P. splendcns, the
only other known species, are as thick as a
horse-hair, and 3 to 4" high.

It is the finest of all the jNFucorini, and
■was at first confridered an Alga, which it
strongly resembles on a superficial exami-
nation, when dry, from its green shining
threads.

Van Tieghem attributes to this a fructi-
fication like that of Si/ziiyites, with which
genus it must idtimately be combined.

BiHL. Fries, Syst. Myc. iii. 309 ; Sum.
Veg. 488 ; Berk. Ann. N. H. vi. 433 ; Van
Tieghem, ^?!«. Sc. Nat 1873, xvii. 202.

PIIYCOMYOETES.— An order ofFungi
composed of microscopic plants of very
simple organization, the mycelium being a
byssoid or flocculent mass, bearing simple
vesicular sporanges (peridiola), filled with
minute spores. The liature of the mem-
branous wall of the peridioles is not yet well
ascertained in all the genera, some authors
describing it as merely a veil, others as a
perfect sac formed b}' the expansion of the
terminal cell of the filament, which is cer-
tair.ly true in 3I?icor. According to our
own observations, the spores aie formed by
free-cell formation in the peridiole, which
ultimately bursts to discharge the spores.

But the division Antennariei cannot stand ;

AT>Tr:xxAr!iA seems to be merely a form of

CAPXODirM ; and Piso:myxa and Pleveo-

PYXis are obscure objects of which little is

known.

In the Antennariei the peridioles are ses-
sile on radiating flocci, which sometimes
send processes which gi-ow up and surround
them, or they are attached to the sides of
eiect filaments; these filaments form whitish
or gieyish patches, on the leaves of trees
and herbs, bearing a close external resem-
blance to Enjsiphe.

The Miicorini are moulds growing on
decaying organic matter, the mycelium
constituting flocks floating in liquids or
overgr(.wing damp substances, while the
delicate spore-sacs or peridioles are borne
at the apices of erect stalk-like and often
extremely branched filaments. The genus
Syzi/f/ites exhibits a remarkable peculiarity.
Each spm'e-sac is formed by means of the
conjugation of two bianches of the ramified
fructification (see Syzygites).

The later researches on the plants of this
group seem to indicate that, as in most of
the Fungal Orders, much remains to be
cleared up concerning the relations of the
forms. See on this subject the article Eu-
EOTiFM, which genus, according to De
Bary's researches, is associated as merely a
second form of fructification, with Asper-
Gn>LUS, upon the same mvcelium.

PH YL ACTEL 'LA, llincks, = Lepralia
pt. (Tlinck-s, Poli/z. 356.)

PIIYLLOBET.— A series of Lichena-
ceous Lichens.

Char. Thallusfoliaceous, depressed, lobed.

BiBL. Leighton, Brit. Lich. Flora, p. 2.

PIIYLLOGONIA'CE^.— A family of
Pleurocarpous Mosses, distinguished bv the
peculiar character of the leaves and their
arrangement. The leaves are either in-
serted horizontally or imbricated vertically,
clasping, and are composed of very narrow
linear parenchymatous cells, appearing
almost confluent into a homogeneous mem-
brane, auricled at the base, with luinute,
parenchymatous, thickened alar cells ar-
ranged orbicularly at the auricles, very
smootb ; tbe leaves stand in two opposite
rows.

This family contains only tbe single small
exotic genus Pltyllfxpiniinn.

PHYLLOM'iTUS, Stein.— A genus of
Flagellate Infusoria. Free, ovate ; flngella
two, unequal, united at the basal portion ;
no mouth. P. undulans, freshwater. (Kent,
Inf. 299.)

■PHYLLOPII'ORA, Grev.— A genus of
Crypt onemiacefe (Florideous Algag), con-
sisting of several species, with a red, rigidly
membranous, stalked, leaf-like, often dicho-
tomous thallus, the lobes of which are often
proliferous ; from a few inches to a foot long,
gi'owing near low-water mark, or in the sea.
(P. rvhens, PI. 4. fig. 4.)

The fructificatiou consists of:- — I. favelli-
dia, scattered over the thallus, containing
minute spores ; 2. antlieridia, wart-like
bodies compcsed of radiating moniliform

2q. 2

PHYLLOPODA.

[ 696 ]

PHYSIOTIUM.

fllameuts foimcl on distinct plants from the
spores ; and 3. telraspores, collected into
sori either towards the apex of the thallus
or on proper lobes.

BiBL. Harvey, Mar. Alg. 142, pi. 18 A ;
Phijc. Brit, pi." 191 ; GreTille, Alg. Brit.
pi. 15 ; Derbes and Solier, Ann. Sc. Nat. 3
i^er. xiv. 277, pi. 37 : Thuret, ibid. 4s6i: iii. 18.
PHYLLOP'ODA. See Extomosteaca.
PHYLLOXE'RA, Fonsc— A genus of
Aphidaj (Homopterous Hemiptera) ; the
species have the fore Aviugs flat on the back,
■with 1 simple stigmal, and 2 simple oblique
discoidal nerves ; the antennae 3-jointed.

These insects are notable from the immense
damage they do, in the vinicolous countries,
to the grape-vines. The apterous broods
feed upon the roots of the vine, exhausting
its juices, producing decay of the leaves, and
absence of fruit. In the autumn, the winged
sexual forms are produced, which spread the
malady abroad, by laying their eggs in new
places. P. vastatrix (PI. 53. fig. 7) is the
vine-pest ; but other species occur on the
oak, &c. The insects may be found by
separating the layers of the roots, and
examining them with a good lens, when
they will be seen in all stages, often sur-
rounded with a zone of eggs.

BiBL. West wood, Intr. ii. ; Fatio and
Demole-Ador, Rap. s. I. Phyll. 1875-76;
Lichtenstein, Ann. A(/ronom. 1876, ii. 129 ;
Robin, Micr. 1877, 953 ; Balbiani, Rev.
Scient. 1874; Cornu, Phyll. vast, 1878
(24 plates).

PHYMATOP'SIS, Tul. — A genus of
Microlichens parasitic on the apothecia
and thallus of Usnefe.

BiBL. Lindsay, New-Zealand Lich. and
Funqi, 442 ; QiC Mic. Jn. 1869, 350,

PHYSAC'TIS, Kutz.— A genus of Oscil-
latoriaceas (Confervoid Algae), improperly
separated from Rividaria, consisting of
freshwater and marine plants, growing on
stones &c., at first globose, and afterguards
vesicular and lobed by peripheral growth
accompanied by gradual decay of the ori-
ginally solid centre. Under this head are
included : —

P. (Rivularia) nitida. Deep olive-green,
tufted and lobed, gregarious ; fronds from
1-12 to 1" in diameter. (i2. hidlata, Berk.)
Marine.

P. (Riv.) plicata. Diam. 1-12 to 1-2" in
diameter ; deep green. Marine.

P. (Riv.) pisum. Globose, dirty green,
1-12 to 1-2" in diameter. Freshwater.

BiBL. Kiitz. Sp. Alg. 332; Tab. Phyc.

Bd. i. pi. 58; HassaU, Fr. Alg. 262 ; Har-
vev. Mar. Alg. 222 ; Berk. Gleanincfs, pi. 2.
fig. 1 ; Rabeuh. Ah/, ii. 2C6.

PHYSA'RUM,"Pers.— A genus of Myxo-
mycetes, containing numerous species
gi-owing on rotten wood, bark, leaves, &c.
They arc nearly related to iJidymium and
Didcrnia, but have a sim^ile membranous
peridium : the filaments are adnate to the
peridium; but in some spores they are
very few, approaching to the condition of
Licea. Some are sessile, others stipitate
(fig. 569) ; the clustered forms (P. hyali-

Fig. 571. Fig. 569.

Fig. 570.

Physarum bryophilum.

Fig. 569. Plants growing on a Plagiochila. Magn. 2
diams.

Fig. 570. A peridium burst. Magn. 25 diams.

Fig.571. Filaments and spores from the same. Magn.
100 mams.

num and utrivulatuvi) are removed to
Berkeley's geims 'Badhamia. P. album is
common.

BiBL. Berk. Br. Fl. ii. pt. 2. 314 ; Mat/.
Zool. and Bot. i. 49 ; Ann. N. H. vi. 431,
2. xiii. 159 ; Fries, System. Myc. iii. 127 ;
Sum. Veg. 153 ; Greville, Cri/pt. Fl. pi. 40.
310; Cooke, Grevillea, 1880; Kent, Pop.
Sc. Rev. 1881, and Inf. 470.

PHYS'CIA, Nyl.— Like Parmelia, but
with the spores bilocular; nianv species.

PH YSOOMIT'RIUM, Bridel.— A genus
of Funariacea? (Acrocarpous Mosses), in-
cluding many Gymnostomaoi other authors.
Physcomitrium pyrifurnie, J^vid. = Gylnno-
stomnm pyriforme, Hedw. Ph. sphcericam
is remarkable as having been found only in
one year in one locality in Britain.

This species exhibits a pretty structure in
a vertical .section of the immature capsule,
the mass of sporiferous tissue being sus-
pended freely in the middle by cellular
threads.

PHYSIO'TIUM, Nees.— A genus of Jun-
germanuiea) (Hepaticse), containing one

PHYSODICTYON,

[ 507 J

PILOBOLUS.

species, P. cochJeariforme, a large plaut,
growing iu purple tufts 4 to 6" long, on
moors aud among rocks in Ireland and the
Scotch highlands.

BiBL. Hook. Brit. Flor. ii. pt. 1. p. 119;
Br. Jim(i. p. G8 : Eiu/l. Bof. pi. 2500 ; Elcart,
Si/?iops. Jintf/. pi. 5. hg. 40 ; Endlicher, Gen.
Plant. Suppl. 1. nos."472-81.

PIiYS6DIC 'TYON, Ktz.— A genus of
Algse, consisting of globular vesicles com-
posed of angular parenchymatous cells con-
taining chlorophyll; diameter 1-12". On
rocks and submerged wood. P. qraniforme
(PI. 3, fig. 14). (Rabenhorst, Ahj. iii! 312.)
PHYSOM'ONAS, Kt.— A genus of Fla-
gellate Infusoria. Rounded, free or fixed by
a slender filament ; obliquely truncate in
front ; tiagella two, unequal ; diam. 1-3000" ;
freshwater and marine. (Kent, Inf. 263.)

PHYTEL'EPHAS, R. and P.— The ge-
neric name of the Palm yielding the Vege-
table-Ivory nut.

PHY^TOCRE'NE, Wallich.— An Arto-
carpaceous tree with wood of very remark-
able structure. See Wood.

PHYTOP 'TID^.— A family of Acarina,
the nature of which is ill-understood. The
member? are found in the buds and gaUs of
plants. The galls, which form warts, tu-
bercles, nail-like growths (fcc. upon the
leaves, and produce distortion of the buds,
were formerly considered fungi, and placed
in the genera Urineum, Phillerium, &c. The
Acari are usually elongate, the body trans-
versely striated, the legs two anterior pairs,
the hinder pairs being replaced by tubercles
or long hairs. They were supposed to be
the larvae of Tetranychus or other Acaiiua,
but theu' eggs are found with them in the
galls. They have not been properly ar-
ranged iu genera and species, being usually
referred to the single genus Phytoptus, Duj ,
They are often very transparent and easily
overlooked, and sometimes can only be
foimd by washing the opened galls, and
searching for them in the wash-water.
They are commonly met with in the galls
of the lime, the vine, the wiUow, the pear, 1
vew, &c., aud are named accordingly P.
"tilue (PL o3. fig. 24), P. vitis, &c.

BiBL. Dujardin, Ann. Sc. Nat. 1857, iii.
lo ; Pagenstecher, Verh. Heidelb. 1859 ;
Frauenfeld, Verh. zool.-hot. G'es. Wien, 1864-
72; Low, ib. 1874; Thomas, Zeitschr. ge-
sammt. Naturw. xxxiii. ; Kaltenbach,
Pflam.feinde ; Briosi, M. M. Jn. xvii. 181
(with copious Bibl.) ; Ormerod, Inj. Ins.
179 ; Mui-ray, Ec. Ent. 365.

PICO'BIA, Hall.— A genus of Trombi-
dina (Acarina). P. Heeri, in the subcu-
taneous cellular tissue of the woodpecker.

Bibl. Megnin, Paras. 248; Haller,
Zeitschr. wiss. Zool. 1877, xxx.

PIGGO'TIA, Berk, and Broome.— A
genus of Sphaeronemei (Stylosporous
Fungi), or perhaps the conidiiferous form of
Dothidea. P. astroidea occurs on the green
leaves of the elm, formino- ii-regidar round-
ish, granulated or wrinkled jet-black patches
(sometimes with a yellow border) on the
upper surface of the leaf. Perithecia soon
confluent, bursting by a lacerated fissure.

Bibl. Berk, and Broome, Ann. N. H. 2.
vii. 9o, pi. 5. fig. 1.
PIGMENT. See Introduction, p. xxxiv.
PIGMENT-CELLS of connective tissue
occur in a few isolated spots only in Man
and the higher Vertebrata, but are widely
distributed m Amphibia and Fishes, appear-
ing especially in the skin, the serous mem-
branes, and the tunica adventitia of the
vessels. The pigment is deposited in gi-a-
nules, which differ in shape and colour.
The pigment-cells of connective tissue are
usually characterized by their beautiful
stellate form and numerous processes. In
Man they occur normally in the eye. The
pigment -granules in Amphibia are collected
in round masses or diffused in the stellate
cells, their movement being evident but
slow. Spontaneous alteration in form of
pigment-cells occurs in the skin of these
animals, and is connected with the change in
colour which they present. See Mel anine.
PILA'CRE, Fr.— A genus of Trichogas-
tres (Gasteromycetous Fimgi).

This genus must not be confoimded with
0)iyyena, to which it bears a cei'tain resem-
blance. One or two of the species are
remarkable for the strong permanent odour,
resembling that of pigs.

Bibl, Berk, and Broome, Ann. N. H. 2.
V. 365, pi. 11.

PILEOLA'RIA, Cast. See Uromyces.

PILEORin'ZA.— A conical hood on, or

shield or guard to, the tips of the roots of

plants, protecting the nascent tissue. See

Root.

PILINTA, KUtz.— A genus of Chaetc-
phoraceousAlgfe. Filaments erect, jointed,
tufted, rooting, forming a spongy stratum.
P. rimosa (PI. 3, fig. 15), on submersed
wood ; marine. (Rabenhorst, Alg. iii. 386.)
PILOBO LUS, Tode.— A geims of Mu-
corini (Phycomycetous Fungi), consisting
of little moulds growing upon dung ; bear-

PILOPHOEON.

[ 593 ]

PILrLARIA.

ing some resemblance iu their structm-e to
Botrijdium among the Algse. The plants
Lave a stolon iferous creeping mycelium,
from wlueh arise fertile pedicels, each cut
off from the mycelium by a septum; the
upper part of the pedicel expands into the
■vesicle, which also becomes shut oft" by a
septum ; in the vesicle or peridiole, spores
are next developed by free-cell formation,
and at the same time' the septum becomes
pushed up into its interior (as in Mucoe)
to form a columella, which ultimately causes
the vesicular peridiole to split off by a cir-
cumscissile dehiscence just above the sep-
tum ; it is thrown off" with elasticity, en-
closing the spores. Tlie development of
P. crystaUiiius has been studied by Colin and
Bail.' They hud the germinating spore to
produce a creeping unicellular mycelial por-
tion, and next a fruit-pedicel, which soon
has the peridiole separated by a septum ;
thus, in its simplest form, this plant consists
of only three cells ; subsequently it becomes
complex by the root-cell or mycelium pro-
ducing numerous stolons. P. crystallinus is
yellowish at first, the peridiole finally black.
P. roridus, Bolt., a doubtful species, is smaller
and more slender than the last, having an
elongated filiform stem.

Bjbl. Berk. Br. Fl. ii. pt. 2. 231 ; Fries,
Sum. Vef/et. 487 ; Cohn, Kova Acta, xxiii.
492 ; Bail, Hot, Zeit. xiii. C30 ; Currey, J.
Liim. Sue. Botany, i. 162.

PILOPH'ORUN,Tuck.— Agenus of Cla-
douiei (Liclienaceous Lichens ). P. Jihula,
on wet rocks, rare. ( Leighton, Lich. Fl. 69.)
PILOT'PJCHUM, Pal. de Beauv.— A
genus of Hypnoid Mosses, including some
Fontincdes of authors.

Pilotrichum antipyreticum, C. Mull.=
Fontinalis antipyrelica, L.

P. squamosum, C. Miill. = F. squamosa,
L.

P. ciIi(itu7n,C MiiYl.^ Anoecfaiiffiion cilia-
tum, Brid., var. y. striafum = A. cUiutum,
Wilson.

P. hcteromaUum, P. d. ^.—Daltoniaheie-
7'otiialla, 11. and T,

PILULA'EIA, L.— A genus of Marsile-
aceous Plants, containing the only British
representative of the order — P. glohuUfera
(fig. 574). Tliis is an iuconspicuous plant
growing in mud at the edges of or in pools,
having a filiform creeping stem, bearing
erect filiform pTeen leaves and delicate ad-
ventitious roots, and producing shortly-
stalked globular spore-fruits, about the size
of a pepper-corn. The anatomical structure

of the stem and leaves is simple : they are
clothed with an epidermis possessing sto-
mata ; and a cross section both of the stem
and the leaves exhibits a central vascular
bundle (of spiral vessels) surrounded by a
sheath of brownish cells, while in the deli-
cate cellular tissue intervening between the
central bundle and the epidermis stands a
circle of air-passages separated from each
other by simple radiating cellular septa.

Fig. 572.

Fig. 573.

Pilularia globulifera.

Fig. 572. h. vertical section of a spore-fruic. Magn.
.5 diameters.

Fig .37-3. Transverse section of a spore-fruit. Magn.
b diameters.

The spore-fruits are liollow cases with an
oiiter tough cellular coat, and an inner more
delicate coat dijipiuginat four perpendicular
lines, as far as the centre, so as to form
dissepiments dividing the fruit into four
chambers (fiffs. 572, 573) ; up the centre of
the outer wall of each chamber runs a raised
ridge, a kind of placenta, whence arise the
sporanges or thecce (fig. 573). These are
pear-shaped sacs composed of a very deli-
cate cellular membrane. Those in the upper
part of each chamber contain a number of
minute globular bodies (microspores), re-
sembhng pollen-grains, immersed in a gela-
tinous liquid. The sacs in the lower part
of the chamber contain only one body or
spore (macrospore) of very peculiar firm ;
it nearly fills the theca, is somewhat oval,
and possesses several coats.

In the development of the spores the
small spores are developed in the usual way,
by the formation of parent cells in the
theca, each subsequently producing four
spores. In the thecfB which have the single
large spore, a number of parent cells are
origiually produced ; and these become
divided into four chambers by septa ; but
then all but one of these decay. This pro-
duces four spores; but out of these four,
only one attains ]ierfect development, the
rest being subsequently dissolved and ab-
sorbed to make room for the solitary large
spore. The two kinds of spore in Pilularia

PILULARIA.

[ r,no ]

PILULARIA.

correspond to the two forms in Selaqi-
NBLLA and IsoETE.s, and to the pollen and
ovules of the Flowering Plants. They are
set free by the dehiscence of the spore-lriiit,
and lie at first inib.'dded in the jelly poured
out by the thecse.

In this state the small spores resemble
pollen-grains, having au outer granular, and
an inner delicately membranous coat, — the
outer coat presenting ridges coi'respouding
to the points of contact in the parent cell.
When set free, tlie spores soon burst at
these ridges, and tlie inner coat is slightly
protruded ; this next bursts and discharges
a number of lontienlor cells, from each of
■which escapes a ciliated spiral spermatozoid.

The mature large spore-s (tig. 575) are of

oval form, and have a thick outer gelati-
nous coat Ci)mpt)sedof prismatic cells stand-
ing perpendicularly on an inner glassy coat ;
the gelatinous coat is perforated at the
summit byafunnel-sha}3ed opening through
which protrudes a pyramidal elevation of the
second, glassy coat ; the last is lined by a
delicate internal coat containing protoplasm,
starch, oil-globules, &c. Soon after the
expulsion of the spore, cell-formation takes
place inside the pyramidal protrusion of the
outer coat, from the cell-contents of the
spoi-e. The glassy coat next splits at this
point into four teeth, and exposes the cellular
structure {protliallium), which increases in
size, and acquires a green colour. An
archegoniuni is next formed on this, con-

Fig. 574.

Fig. 575.

Fig. 578.

Fig. 576.

Fig. 577.

Pilularia globulifera.

Fig. S"4. Natural size.

Fi;;. 57o. An ovule spore. Magnified 25 diameters.

Figs. 576 & 577. The same in germination. Magnified 25 diameters.

Fig. 578. Germinating spore more advanced. Magnified 10 diameters.

sisting of a cell (embryo-sac) lying in the
substance at the apex, with a canal Ijordered
by four papillose cells leading to it. A
spermatozoid fertilizes the free embryo-ceU
contained in the archegonium ; and this be-
comes developed into a new plant within
the substance of the prothallium (fig. 577),
sending out a leaf on one side and an ad-
ventitious root on the other, tangentially to

the surface of the spore. In this stage
(fig. 578) the j'oung plant, with the remains
of the spore, somewhat resembles a germi-
nating Monocotyledonous seed. Finally, as
the young plant increases in size, the rem-
nants of the spore-coat are thrown off.

BiBL. Valentine, Linn. Tr. xvii. ; Hof-
meister, Vergl. Unters.\9>5\,\0Z ; Henfrey,
Ann. N. H. 2. ix. 447 j Hanstein, Pilul. ^c.

PINE-APPLE.

[ 600 ] PITTED STRUCTURES,

1866, Brauu, Monatsb. Berl. Ak. 1870;
Sachs, Bot. 444.

PINE- APPLE. See Bro>ieliace;e.

PINNULAEIA , Ehr.— A genus of Uia-
tomacefe, family Naviculacese.

C/mr. Frustules single, free, longer than
broad ; front view linear or oblong ; valves
navicular, elliptical, lanceolate, or oblong
(side view), with a median line, and a
nodule at the centre and at each end ; sur-
face exhibiting transverse or slightly radi-
ating striae or furrows (costse).

This genus diifers from Navictda in the
strife not being resolvable into dots. They
ai'e mostly distinct under ordinary illumina-
tion. In some of the species tliey are absent
in the middle, leaving a transverse clear
space or band, resembling in appearance the
stauros of Staurmieis. Many species.

P. nohilis (PI. 15. fig. 1, side view).
Valves linear, dilated in the middle and at
the rounded ends ; strige coarse. Fresh-
water and fossil; length 1-100 to 1-70".

P. viridis (PI. 15. fig. 2, side view).
Valves elliptical, somewhat turgid, ends
obtuse ; freshwater ; length 1-500 to
1-220"; common.

j3. Strise parallel, absent from a transverse
band.

P. ohlonga (PI. 15. fig. 8, side view).
Valves linear-oblong, ends rounded ; fresh-
water and fossil ; length 1-120" ; common.

P. radiosa (PI. 15. fig. 4, side view ; fig. o,
front view) . Valves lanceolate, ends some-
what obtuse ; fi-esh water ; length 1-500" :
common.

BiBL. Smith, Br. Died. i. 54, ii. 95 ; Ehr.
Abh. 1840, 20; Donkin, Mic. Jn. 1861, 8;
Pritchard, Inf. 899; Kutz. 8p. Alg. 81;
Gregory, Diat. of Ckjde, 7 ; Q. Micr. Jn.
ii. 28, 98 ; Griin, Wien. Verh. 18G0, 524 ;
Rabenh. Alg. iii. 209 ; Pfitzer and O'Meara,
Qu. 3Iic. Jn. 1872, 386.

PI'NUS, L.— A genus of Coniferaj (Gym-
nospermous Flowering Plants), presenting
many interesting points of structure. The
most familiar example is the Scotch Fir
(P. sylvestris) ; but a great number of other
species are cultivated in this country. For
the microscope they yield instructi^ e objects:
— in the wood (PI. 48. fig. 1), composed of
peculiarly pitted cells (see CoNiFERiE) and
traversed by turpentine-reservoirs ; in the
Babk, which has a kind of false corli ; in
the development of the Gymnospermous
Ovules, and in the structure of the Pol-
LEN-grains.

The wood of species of the genus Pinus

frequently occurs in a fossil condition (Pl.
25. figs. 29-33).

Bibl. See the articles above cited.

PISOM YX' A, Cordni Brgucladimti, Ktz.).
— A genus of Mucorini (Phycomycetous

Fig. 579.

Pisomyxa racodioides.
Magnified 200 diameters.

Fungi), growing upon leaves. A species
has occm'red in Ceylon on the leaves of
A7}wmum.

Bibl. Fries, Swn. Veg. 406 ; Corda, Ic.
Fung. i. pl. 6. fig. 292 ; Berk, and Broome,
Linn. Jn. xiv. 139, t. x. f. 54.

PISTIL.— The parts of a flower included
in the terms ovary, style, and stigma. It
is in theory composed of modified leaves
or carpels.

PISTILLA'RIA, Fr.— A genus of Cla-
variei (Hymenomycetous Fungi), consisting
of small club-shaped heads which are con-
fluent with the ste-m. There are about six
species indigenous to this country, of which
that on fern-stems is the most common.

Bibl. Fr. Ep. 586; Berk. Outl. 286;
Cooke, Handb. 342.

PISTILLID'lUM=AHcnEGONiuM, the
female reproductive organ of the higher
Crvptogamia.

PITH. SeeMEDtTLLA.

PITHOPH'ORA, Wittr.— An obscure
genus of Algse. (Wittrock, Qu. M. Jn.
1877, xvii. 293; Moore, Jn. Bot. 1877;
M. M. Jn. xviii. 40.)

PITTED STRUCTURES of Plants.
— The secondary deposits of cellulose which
form the layers of thickening of the walls of
vegetable cells are seldom uniform or homo-
geneous in character. In most, if not in all,
cases some special microscopic structure
may be distinguished, either by mere in-
spectiDU or on the application of reagents.
These layers, .spoken of more particularly as
to their nature under Secondary depo-
sits, may be divided into two classes, com-

PITTED STRUCTURES. [ 601 ] PITTED STRUCTURES.

prehending pretty accurately all the varied
conditions, namely: — the Spiral deposits,
where the seconclary layers assume the
aspect of Hbres applied upon the inside of
the cell-wall; and Pitted, ov,ns they are often
tenned, Porous deposits, where layers are
applied over the whole internal surface of
the cell, which layers present orifices of dif-
ferent character.s,'leaving- the primary mem-
brane hare, and forming in this way a pit as
viewed from the inside of the cell. When
the secondary layers are comparatively thin,
their presence is often overlooked ; and the
pits have thus often been mistaken for ori-
fices or jwres (figs. 580, 581) in the primary

Fig. 580.

Fig. 581.

Pitted cells of Elder pith.
Magnified 250 diameters.

membrane ; but such pores are never origi-
nally present ; the closvire of the pit by the
layer of primary membrane may always be
demonstrated in young structures ; and when
orifices really do occur in cell-walls, these
ai'ise from the absorption of the primary
cell-membrane converting the pit into a
pore. The best way of demonstrating that
young spotted cell- walls are only pitted aud
not perforated, is to apply sulphuric acid
and iodine for the production of the blue
colour in the primary cell-wall.

Simple pits, of no great depth, occur on
the slightly thickened walls of most perma-
nent parenchymatous cells ; they may be
seen in the cells of herbaceous stems, in
pith, bark, in the cells of the parenchyma of
leaves, &c. (Figs. 580, 581 ; PI. 47. fig. 14.)

In most prosenchymatous wood-cells, or
liber-cells, aud in the woody cells of the
stones or shells of fruits and seeds, the pits
are far more clearly evident, and become
more and more distinct (PI. 48. fig. 3), as
the layers of thickeniug increase in number,
since, by the successive application of these,
the pits are deepened (with the contraction
of the cavity of the cell) until they become
canals or tubular passages radiating from
the central cavity (PI. 47. fig. 23). In these
cases it is evidently seen that the pits of
adjacent cells and ducts con'espond to each

other at their outer extremity ; and in old
tissues, when the primary cell-walls have
been absorbed, these coincident pits form
tubular canals leading from one cell to
another. It has been observed thattwo (n-
more pits sometimes become confluent in
the later internal deposits, so that the in-
ternally simple orifice leads out to several
branches corresponding to the original pits
on the wall of the cell. In rare cases, simple
pits occur on the outer walls of epidermal
cells, as in Ci/cas (PI. 47. fig. 28).

Pits of the above kinds occm" on the
structures called ducts (see Tissues, -stege-

Fig. 582. Fig. 583.

Fig. 582. Pitted duets of Clematig. Magii. 100 diams.

Fig. 583. Side wall of a cell of Pine, with bordered

pits. Magniiied 200 diameters.

table), formed of cells applied end to
end and confluent (fig. 181, page 271).
These large pitted tubes (which occur abun-
dantly in most woods, witli the exception
of that of the Coniferas) are sometimes
termed bofhrenchi/ma , signifying jntted tis-
sue ; but the character not being exclusively
applicable to them, the name is bad.

In many pitted ducts, and in the pitted
wood-cells of many plants, especially of the
Coniferae, the pits present a greater degree
of complication. The markings on the walls
of the wood-cells of most of the Coniferae,
for example, consist of pits surrounded by a

PITTED STRUCTURES. [ 602 ] PITTED STRUCTURES.

broad rim (fig. 583 ; PI. 48. figs. 1, 4, 5) ; tlie
portion within the rim projec-ts somewliat
into the cavity of the cell, and appears like
a lenticular body attached on the wall; hence
tiie markings were formerly termed the
" glands " of Coniferous wood. In reality,
however, while the pits themselves resemble
ordinary pits, the broad rim, or rather the
circular line outside the pit, depend* on a
condition of the cell-wa'.l outside the mem-
brane, and is merely the outline of a lenti-

Fig. 584.

r.iu

pt.

Section of Pine wood at right angles to the pitted
walls, p.f, walls of a pitted cell ; c.j, cavity of a cell ;
c. I , lenticular cavity between two adjacent pits ; r. in,
cells of a medullary ray, the pits have no rim here.

Magnified 400 diameters.

cular cavity existing between two adjacent
cells, the boundary of which is visible
through the wall on account of the trans-
parency of the latter : the nature of this
structure is very evident in sections made at
right angles to those which show the bor-
dered pits in face (fig. 584 ; PL 48. fig. 1 b).
In most of the ConiferaB the wood is ex-
clusively composed of large elongated pros-
enchym'atous cells, with bordered pits of
this character on the side walls (that is, on
the walls standing radially or perpendicular
to the bark) ; the pits, however, which lie
on parts of the wall adjoining the cells of

medullary rays, ai'e generally devoid of the
rim.

Similar bordered pits occur very generally
on the walls of the pitted ducts of Dico-
tyledons ; but as the wood is here of mixed
composition, and the ducts adjoin cells as
well as other ducts, independently of the
medullary rays, we often find a greater va-
riety of conditions on the wall of the same
duct, which may have bordered pits when
adjoining another duct, and simple pits, or
pits with a double outline, when adjoining
cells. The pits with a double outline (PL 48.
figs. 15 b, ic 20) are of difiereut nature from
the bordered pits (PL 48. figs. 13, 14, 15 a,
16, 18), the double outline depending simply
on the fact that the later or more internal
layers of thickening do not reach the edge
of the orifice in the earlier secondary de-
posits, so that the pit is conical, or rather
has sloping edges, the circumference at the
primary membrane being rather less than
that of the margin next the cell-cavity. A
peculiar modification of this unequal mode
of deposit is seen in company with the true
rim or border in many cases (PL 48. figs. 14,
1(3, 18), where the central spot or ongiual
pit appears in the middle of a sUt running
across .the circle indicating the border ; this
slit indicates the alteration of the shape of
the gap in the secondary deposits in the
successive layers, and corresponds to the
inner margin of the pit, where this has the
form of an elongated groove or slit, gi-adu-
ally diminishing- to a small round hole
towards the primarv cell-membrane (PL 48.
fig. 18«). Sometimes (PL 48. fig. 18 «r, b)
the two or more slits formed in this way on
contiguous pits become confluent. The last
condition indicates a transition to the more
sparing form of the secondary' deposit where
it appears as a modification of a spiral fibre
or fibres; and the later secondary deposits of
pitted ducts do sometimes actually assume
this Ibrni, and produce a spiral-!ibruus layer
of thickening inside the layers perforated by
pits. This is the case in Taxus (PL 48.
figs. 4), in the Lime (PL 48. fig. 13), and
Mezereon (PL 48. fig. 19 b), &c.

Ilartig and Mohl have described a pecu-
liar kind of pitted tissue formed of cells,
which the former calls Siebrohren, or sieve-
tubes, the latter clathrafe cells. They are
thin-walled cells occurring associated with
the prosenchymatous liber-cells of Dicotyle-
dons, and forming part of the vasa j)ropria
of Monocotylednns; having their walls
mi.rked with large shiUow pits, the mem-

PITTED STRUCTURES. [ 003 ]

PLAGIOCIIILA.

Itrane of the pits beinp: ag-iin vovv finely
punctate or reticulated ; llartig regards the
line punctuations as holes.

For tlie guidance of microscopic observers,
•we may furnish a series of examples (in ad-
dition to those of the Conifku.^:, PL 48.
fiffs. 1, 4, 5), of the dilferent kinds of mark-
ing- on pitti'd cells and ducts.

A. Forms wliere there is no spiral-Jihrous
secundiin/ deposit.

a. Bordered pits uniformly distributed,
■without reference to adjacent structures ;
E!cea(inm acicninata, Clematis Vilalha (PI.
4± lig. 18).

b. Jiordered pits fewer on the walls ad-
joining cells: Acacia lophantha, Sophora
Japotiica.

c. Bordered pits on the walls adjoining
duets, while the walls adjoining wood-cells
have few or no bordered pits, and those
next the medullary rays have pits without
a border : elder, beechj hazel, poplar, alder,
plane, apple, &c.

d. Bordered pits on the walls adjoining
ducts, but with large pits devoid of a bor-
der where adjoining cells : Cassi/tha (jlahella
(PL 48. tig. 14), Bombax pentandruyn (PL 48.
tig. 15).

e. A modification of the last, where the
bordered pits have the form of slits as wide
as the ducts when adjoining ducts, while
the walls adjoining cells have large pits
without a border : Chilinnthiis arboreus
(PI. 48. fig. 17); the vine (in a less striking
manner). Urt/nc/ium maritimiim (PL 48.
fig. 21) exhibits a <;onditiou approaching this.

/. Sieve-tubes or clathrate cells, large thin-
walled cells with round, oval, or elongated
thinner places (pits) on their walls, the mem-
brane of the pit being finely reticulated or
perforated like a sieve. These are found in
the liber of Dicotyledons, as in Biynonia,
the lime, the vine, elder, pear, &c., and in
the central part of the vascular bundles of
Monocotyledons, as Musa, Asparayus, &c.

B. Forms where a spiral-Jibrotis structure is
added after the jjits.

g. All the ducts with bordered pits, but
the larger ducts with smooth walls, the
smaller with a spiral fibre : Clematis Vitalba,
Uimus campestris, Mortis alba.

h. All the ducts closely pitted, with
slender fibres between the rows of yjita :
Hakea oUifolia.

i. The larger ducts with pits, the smaller

without ; both kinds with spiral fibres on
the internal surface: J)ii/)/<nr Mrzereinn
(PL 48. fig. 19), PasserinajViformis, Genista
canariensis.

J. The walls adjacent to other ducts
pitted, those next ells with very distant
pits, or devoid of them ; all the walls with
fibres : the lime, horse-chestnut, sycamore,
cornel, holly, hawthorn, Pruiuis Padus, P.
virjiiniana, &c.

The last set of forms allies these struc-
tures to those characterized pecidiarly by
the SpiRAL-fibrous Structurks : and, as
will be indicated there and under S R( :ond ary
DEPOSITS, the smooth layers of thickening,
such as those between the pits of Pmas,
may be made to show a spiral structure by
the action of reagents.

For the micro-chemical conditions of
these objects, their development and rela-
tions, see Secondary deposits ; Tissues,

Vegetable ; and Cei.l,

B table.

BiBL. Works on Structural Bcjtany, and
the Bihl. of Spiral structures.

PLACENTA OF Plants.— The region
of the carpel whence ovules arise. Stroma
would be a preferable term.

PLACO'DIUM.— A genus of Placode!
(Lichenaceous Lichens) ; 13 species, on
rocks and Avails. (Leighton, Lick. Fl. K'O.)
PLACOPSIL'INA , B'OiVignj.—Litvolre
of irregular growth and attached, belong to
this subgenus.

BiBL. Carpenter, For. 143.
PLA'CUS, C'Ohn. — A genus of Holo-
trichous Infusoria. Free, ovate ; surface
indurated, reticular, mouth inferior ; move-
ment rotatory ; length 1-780"; saltwater.
(Kent, Inf. 489.)

PLAGIACAN'THA, Claparede.— A ge-
nus of Acanthometrina (Rhizopoda).

Char. The spicula, which are branched
and without a central canal, do not unite
in the centre of the body, but on one of the
sides, so as to form a scaffolding on which
the sarcode rests; pseudopodia elongating
either at the ends or sides of the spicula to
which they are attached, and which they
unite more or less together.

BiBL. Clap, et Lach. Etudes, 461.
PLAGIOCIU'LA, Nees and Montague.
— A genus of Jungermannieaj (llepaticfe),
containing a number of British species, viz. P.
[Ju7i(fermannia,ilook.)aspleni(iides,spinnlosa,
decipiens, resupinata, undiduta (fig. 321),
planifolia, nemorosa, and umbrosa, some of
which, especially P. a-:plenioides (fig. 585),
are acong the most frequent and finest

PLAGIODISCUS.

[ 604 ]

PLANARIOLA.

Fig. 585.

plants of the family, its stems gi'owing from
3 to 5" long.

BiBL. Hook. Br. Fl. ii.
pt. 1, 111 ; Br. Jung.
pis. 13, 14 ; Ekart, >S>h-
ops. Jung. 6 et seq, pi. 1 ;
Endlicher, Gen. Plant.
Supp. 1, No. 473.

PLAGIODIS'CUS,Gr.
— A gemis of Diatoma-
cese. Allied to Surirella,
but the costae radiating
at the ends. 2 species ;
valves reniform ; Hondu-
ras. (Grunow, M. M. Jn.
xviii. 172, figs.)

PLAGIOG'NATH.1,
Duj. — A genus of Rota-
toria containing- species ^it%t^„U^|fait.
included by Enrenberg
in the genera Notommata, Diglena, and
Distemma ; distinguished by the arched
back and peculiar jaws.

BiBL. Duj. Inf. 651; Pritchard, Itif.
692.

PLAGIOGRAM'MA, Grev.— A genus
of Diatom acese, family Fragilarife.

Char. Frustules quadrangular, united into
a short fascia; valves with two or more
sti'ong, pervious transverse costre, and mo-
niliform generally interrupted strise.

BiBL. Greville, Mic. Tr. 1865, 1866;
Rabenh. Fl. Eur. Alg. i. 117 ; Pritchard,
Infus. 778.

PLAGIOPH'RYS, Clap.— A genus of
Actinophryina (Rhizopoda).

Char. No carapace, pseudopodia nume-
rous, arising from one point of the surface
of the body. 2 species ; fi-esh water. P. cy-
lindrica (PI. 52. tig. 17).

BiBL. Clap, et Lach. Infus. 453 ; Archer,
Qu. Mic. Jn. 1871, 146.

PLAGIOPOGON, St.— A genus of Ho-
lotrichous Infusoria. Free, oval, longitudi-
nally furrowed, oral setee rigid. P. cohps ;
length 1-300". (Kent, /«/. 508.) ■

PLAGIOP' YLA, Stein.— A genus of Ho-
lotrichous Infusoria. Ovate ; mouth ven-
tral, with an undulating membrane ; sur-
face with trichocysts. 3 species ; fresh and
salt water. (Kent, Inf. 538.)

PLAGIOT'OMA, Duj.— A genus of Bur-
sarina (Infusoria ciliata).

Parasitic ; in the intestines and their walls
of Vertebrata and luvertebrata, and in the
mucus of Mollusca. 7 species. P. lumbrici^
in the earthworm j P, coli, in the human in-
testine.

Clap, et Lach.

A genus of

BiBL. Duj. Inf. 504
Infus. 235.
PLAGIOTRICHA, Kt

Hypotrichous Infusoria : allied to Oxgtncha
2 species; freshwater. (Kent, Inf. 771.)

PLAGIOT'ROPIS, O'Meara.— A genus
of Diatomaceae closely allied to Amphi-
prora, Ehr.

BiBL. O'Meara, Qu. Mic. Jn. 1874, 88.

PLANA'RIA, MiilL— A genus of Annu-
loida, of the order Turbellaria, and sub-
order Planarida.

Char. Body soft, flattened, oblong or
oval, not jointed, covered with vibratile
cilia ; neither suckers, bristles, nor leg-like
appendages present.

Some parts of the structure of these ani-
mals have been noticed under Annul at a
in speaking of the Turbellaria. The mouth
is situated on the under sm-face of the
middle of the body, at the end of a retrac-
tile proboscis ; there is no anus ; the mouth
leads to a capacious stomach giving ofl
dendritically-branched caeca, somewhat as
in one joint of a Tcenia (PI. 21. fig. 14).
Their motion is continuous and gUding,
upon water-plants, or the sides of glass jars.
The anterior part of the body exhibits a
curved row or a single pair of eyes, and
sometimes ear-like projections. They mul-
tiply by division, and the formation of ova,
which are enclosed in a coloured capsule.

Some of the species are very common in
pools, and resemble, at first sight, minute
leeches. P. nigra, which is black, has a
row of marginal anterior eyes, and two
lateral and one mesial projection ; length
about 1-2". P. hrunnea, dusky-brown, with
a dark mesial line ; eyes as above ; length
rather less. P. lactea, cream-coloured,
tinged with pale reddish brown, truncate in
front, Avith two slight lateral auricles ; eyes
two or foiu- ; length 1-2 to 3-4". P. torva.,
grey or black : obtu.-e in front, angles
rounded, centre proj ecting ; eyes two, with
a white halo ; length 1-2". Of the other
species some are marine.

BiBL. Johnston, Non-parasitical Worms ;
Duges, Ann. Sc. Nat. 2. xv. and xxi. ;
ffirsted. System, d. Plattioiirmer ; Diesing,
Helminth. ; Daly ell. Powers of Creation, ii. ;
Schultze, Naturg. TwhelL ; J luxley, Cofnp.
An. ; Vaillant, Mn. Mic. Jn. i. 311 ; R.
Lankester, Pop. Sc. Rev. 1867, vi. 388 ;
Moseley, Phil. Trans. 1877, xvii. lOo.

PLANARI'OLA, Duj.— A doubtful ge-
nus of Infusoria.

P. rubra (PI. 31. fig. 65). Aquatic, in

PLANORBITLINA.

[ 605 ]

PLATYZO^IA.

decomposing vegetable matter ; length
1-250".

BiBL. Du]. Inf. 568.

PLANOKBULl'NA, D'Oib.— A genus
of Hyaline Foramiuifera. Shell spiral,
coarsely porous, subnautiloid or outspread,
often parasitic ; having from 15 to 200
chambers, with single septa and slight
rudiments of the canal-system. Aperture
sometimes produced and lipped. Compla-
nate (PI. mechterranensis, PI. 24. tig. 10) ;
plano-convex, Truncatulina (T. lobatula,
PI. 24. fig. 9) ; rotaliiform {PL Haidingerii,
PI. 24. tig. 6 ; PI. veneta, fig. 12) ; or sub-
nautiloid (AnomaUna and Planulina).
Smooth; limbate (Planulina); or granulate.
In all seas ; fossil in the Carboniferous,
Lias, and later formations.

BiBL. Carpenter, For. 206 ; Parker and
Jones, Phil. Tr. civ. 379,

PLANTA'GO. — The common plaiutaiu ;
its leaf and hairs furnish excellent exam-
ples of Cyclosis. See Carpenter, Microscope,
p. 431.

PLANCJLA'RIA, Defi-ance.— A notice-
able gi'oup of delicate, elongate, flattened
Cristellarice, connecting the nautiloid with
the margiuuUne varieties, come under this
name. Recent and fossil.

BiBL. Parker and Jones, Ann. N. H. 3.
V. 114 (crepidtda^ ; xii. 215 ; 4. viii. 166.

PLANULI'NA, D'Orb.— a subgenus of
Planorhulina ; flat, discoidal, subsymmetri-
cal, and with raised margins and septal
lines (Umbate). Recent and fossil.
BiBL. Carpenter, Introd. For. 207.
PLASMODIUM.— A sponge-like net-
work, formed by the union of the pseudo-
podia of amoeboid bodies.

PLAS'TIDS. — The simplest living forms,
and the most elementary parts of tissues,
consist of (1) small particles and masses of
protoplasm without a nucleus or any trace
of structure (our protoplasts, 1856), (2) of
similar portions of protoplasm in Avhich a
nucleus has been dift'erentia,ted. The first
group Hackel terms Cytodes, the second
cells ; and both are grouped under the head
of Plastids.

The cytodes, or the protoplasmic masses
-s\dthout a nucleus, are : —

GymnocytodtB, or naked cytodes. Such
are the freely moving Monera, the non-
nucleated Plasmodia of Myxomycetes, and
of several other Protista, the amoeboid
erms of the Greyariiice proceeding from
he pseudo-naviculse, &c.
Lepocytodce, or covered cytodes. These

are plasma-masses without a nucleus, en-
closed in an entire or incomplete uiembrane
or shell. For example, the encapsuled
resting condition of vi\a.nyLepomonera,mimy
Siphoncca, and numerous other lower plants,
and the so-called non-nucleated cells of
many higher plants and animal tissues.

The cells or cyta are plasma-masses with
a nucleus, and are divided into : —

(xymnocyta, naked cells. Such are the
naked plasma-masses with a nucleus, but
without a membrane or shell ; for example,
the true Amoeba, the naked zoospores of
Alga;, the eggs of Siphonophora, and other
animals, the colomiess blood-cells, many
nerve-ceUs, &c.

Lepocyta, or covered cells. Such are the
cells of animals, plants, and tissues with
nuclei and cell-walls. See Pkotista,
Cytode.

BiBL. Hackel, Biol. Studien, H. i. ; Qu.
Mic. Jn. 1869, 331 ; Hallier, Plastids, 1878.

PLATINUM.— The sodio-chloride of
platinum crystallizes in prisms and plates
which polarize light; while the potassio-
chloride of platinum yields several forms,
which do not polarize light. This reaction
of the soda-salt has been proposed as a
means of distinguishing soda from potash,
or detecting minute quantities of the
former.

BiBL. Andrews, Chem. Gaz. 1852, x. 378,

PLATYCE'RIUM, Desv.— A geims of
Acrosticheee (Polypodiaceous Ferns), o
species ; tropical. (Hooker, Syn. 425.)

PLATYCHE'LIPUS, Br.— A genus of
Copepodous Entomostraca. P. littoralis ;
brackish water. (Bradv, Copep., Ray Soc,
ii. 102.)

PLAT YC 'OLA, Kt.— Like Vaginicola,
but the sheath decumbent, and attached by
one side. Freshwater ; several species.
(Kent, Inf.7?A.)

PLATYG'RAPHA, XyL— A genus of
Graphidei (Lichenaceous Lichens). P.ri-
mata, on ash trees, rare. (Leighton, Lich.
Flor. 388.)

PLATYS'MA, Hoffin. — A genus of
Ramalodei (Lichenaceous Lichens). 10 spe-
cies, on rocky mountains &c. (Leighton,
Lich. Fl. 93.)

PLATYTHE'CA, St.— A genus of Fla-
gellate Infusoria. -Ovate, with a decumbent
rugose carapace ; flagellum single ; length
1-1200" ; on Lemna. (Kent, Inf. 262.)

PLATYZO'MA, Br.— A genus of Glei-
cheniaceous Ferns. P. tnicrophyllum, Aus-
tralia, (Hook. Syn. 11.)

PLECANIUM.

[ 606 ]

PLEUKOSIGMA.

TLEC A 'XI UM, Reuss.— Texfuktrlce with
sandy sliell-titsue rome under this lieadiuo:.

BiBL. Reus?, Sifziim/sh. Wien, xliv. 38-3.

PLEOPEL'TIS, Hu'mb. ;ind BoDpl.— An
exotic genus of Polypodiefe (Polypodioid
Ferns), remarkable for the presence of
peculiarly formed so-called paraphyses in
the sori, performino- the function of an
indusium. These bodies are peltate, or
like minute fiat mushrooms or umbrellas
exptinded over and sheltering the spurauges
(ligs. 586, 587).

Fio-. 586.

Fig. 587.

Pleope)tis nuda.

Fig. 58i5. A sorus, seen from above.

Fig. 587. Vertical section of ditto.

Magnified 2.5 diameters.

-Mosses vrith late-

A genus

PEEUROCAR'PI.

ral fruits.

PEErROCAR'PUS, Braun
of Zygnemace* (Confervoid ALie)

2 .-species, in freshwater pools. (Rabenh.
Alq.m. 258.)

■PLEURUCLA'DIA, Braun.— A genus
of Fucoiden?-, group Plifcosporepe. P. In-
ciifU-is: freshwater, (llnheuh.. Alg . iii. 393.)

PEEUROCOC'CUS, IMeneg.— A genua
of Pfflraellacefe ( Uni cellular Algae).

Clt'ir. Cells single or collected in glo-
bular or cubical masses, globular or angular
from pre-ssure, with a central nucleus ;
cytioderni thick and hyaline; cell-contents
homogi'neou*, green or reddish. Multipli-
cation by Jiltemate fission in opposite direc-
tions. G(;nidia formed, in special cells.
Thev present the greatest similarity to the
gonidia of I^ichens. Several species =
forms of Prof.ococcus ?

Binr,. Meneg. Nosfoch. 38; KdgeW, Si/d.
124; Rabenh. .-!/,'/. iii 24.

PLEURODEB'MIUM, Kiitz.— An ob-
scure genus of DiatoHiacea;, allied to Stria-
iella\ maiine; Africa.

BiBL. Kiitz. Sp. A/q. 115.

PLEUROM'ONAS", Perty.— A genus of
Flagellate Infusoria.

Char. Reniform, extremely delicate,
small, colourless; flagellum single, from
the concave side of the body, three times
its length. P. jnrulans; motion jerking;
stasnant water. (Pertv, Lehenrf. 111.)

PLEURONE'MA, "Duj.— A genus of
Holotrichous Infusoria, family Colpodina.

Char. Body oblong-oval, dejn-essed, with
a broad lateral orifice, from \\ liich a bundle
of long, curved, floating and contiactile
ciliary filaments issue.

F.' chrysalis, (crassa) D. (PI. 31. fig. 66).
Freshwater. Other species.

Bir.L. Duj. Infi/s. 473; Clap, et Lach.
Inf. 274 : Kent, Inf. o42.

PLEUROPH'RYS, Clap.— A genus of
Actinophryina (Rhizopoda).

Char. Body invested with a sheath in-
crusted with extraneous siliceous particles.
P. sphcerica. Freshwater.
BiBL. Clap. etLachm./«/w6-. 454; Archer,
Qu. Mic. Jn. 2870.

PLEUROPYX'IS, Cordn.— A genus of
Mucorini (Phycomycetous Fungi), growing

Fig. 588.

Pleuropyxis microsperma.
Magnified 200 diameters.

upon leaves and stems. This genus is im-
perfectly known.

Bibl' Coida, Icon. Fnnq. pi. 6. fig. 291.

PLEUROSIG'MA, Smith.— A genus of
Diatoma( eoe.

Char. P'rustules single, ft-ee, lorger ihau
broad ; front view linear or hnear-laiiceolate;
valves navicular, sigmoid, with a longitu-

PLEUROSIGMA.

[ 607 ]

rLEUlU)8IGMA.

dinal line, and a nodule in the centre and
at each end.

Theniedi.in line and nodides con-ist of an
internal tliiekening of the valves; at the cor-
responding parts ; the line is best seen in
the front view (PI. 1-j. fiy. 16); it is occa-
sionally found in a iractured valve, pro-
jecting as a solid highly refractive rod, the
thinner adjacent portions of the valve being
broken aAs ay ; for brevity, it may be called
the keel.

The valves exhibit spurious strife, arising
from the existence of rows of dots, of which
we have already treated under Diatoma-
CBJE. The.=?e s'trias and dots are in most
species very difficult to detect, requiring
the use of oblique light, and the modern
condensers with the stops ; the principles
which should guide in the search for them
have been explained under Axgular aper-
ture ; the preliminary preparation of the
valves is also essential (Diatomace^, p.
2.30).

Most of the species are found in salt or
brackish water ; a few in fresh water. They
often abound upon the surface of mud.
Conjugation or the formation of sporangia
has not been observed. The frustules are
.•sometimes foinid enveloped in amorphous
mucus, and those of one species have been
found within gelatinous tubes.

Many species have been described, of j
which those that have been used as Test-
objects will be enumerated. The mea-
surements are mostly those of W. Smith
and E. Beck, with which our own have
coincided very nearly. The species are
arrarged according to the finene.'-s of the
markings, which coincides with the diffi-
culty witli which they are detected and
resolved into dots ; and the appended figures
express the number of strife or rows of dots
in 1-1000".

Stfice oblique (dots alternate or quin-
cuucial, PI. 15. fig. 40).

P. formosmii (PL 15. fig. 2o). Broadly
linear, attenuated towards the ends ; sig-
moidure evident ; keel oblique ; length
1-60" ; stria; 36. INlarine.

P. decorum (PI. lo. fig. 26). Ehomboid-
linear ; attenuated ; sigmoidure very evi-
dent; keel oblique; length 1-90"; striag 36.
Marine.

P. speciosmn {fig. 28). Linear-lanceolate ;
sigmoidure resulting from the curvature of
one ma: gin of each half of the valve, the
opposite margin of each respective half

being nearly straight; keel in each half
forming two curves; very oblique near the
ends; length l-!iO"; marine: striaa 44. The
halves of the valves somewhat resemble the
blade of a pocket-kuif.'.

P. strigosion (tig. 29). Linear-lanceolate;
ends rather obtuse, sigmoidure t-light ; keel
nearly straight in the middle, curved near
the ends; length 1-00"; stria; 45. Marine.
Fig. 40 represents the striie resolved into
dots.

P. quadrat mn (fig. 34). Rhoiuboidal, acu-
minate at the ends; sigmoid ui'e evident
towards the ends ; keel curved, nearly me-
dian ; length 1-150" : marine : strite 45.

/'. elonyatum (PL 15. fig. 31, and PL 1.
fig. 18). Linear-lanceolate, acuminate ; sig-
moidure slight, uniform ; keel median ; length
1-80" ; marine ; strife 48.

P. rigiduin (fig. 30). Linear-larceolate,
obtuse at the ends ; sigmoidure slight ; keel
nearly median; length 1-70"; marine;
stri;T3 48.

P. anf/ulatum (PL 15. fig. .33). Rhomboid-
lanceolate or anguUu-lanceolate ; sigmoidure
evident; keel nearly median; length 1-110";
marine; stria; 52. PL 1. fig. 16" represents
a valve with the strife resolved into dots ;
PL 15. fig. 41 represents the dots very
highly magnified ; and PL 15. fig. 46 exhi-
bits the appearance of hemispherules, which
some authors consider to form the true
structure.

PL 15. fig. 33 a represents a specimen
with the endochrome and nucleus.

/3 (fig. 33 6). Simply and narrowly lan-
ceolate, ends acute.

7 (fig. 33c). Ends beaked; abruptly
flexed.

P. cestvarii (fig. 35). Lanceolate ; ends
abruptly tapering, short and beak-like; sig-
moidure evident ; keel not median ; length
1-250" ; marine ; strife 54.

P. inter meditim (fig. 36). Narrowly
linear-lanceolate, acute ; sigmoidure none,
or merely indicated by a slight inequality
in the opposite margins of the valves : keel
nearly straight and almost median ; length
1-140" ; marine; stripe 55.

/i P. nuhecvla. Ends obtuse ; slightly
more lanceolate, and shorter; marine;
strife 55.

P. delicatnlum (fig. 32). Very nairowlv
linear-lanceolate ; sigmoidure evident ; keel
nearly central; marine; length 1-1.30";
strife 64.

P. obscurum (fig. 27). Linear, attenu-
ated near the ends ; sigmoidure shght ;

PLEUROSIGMA.

[ 608 ]

PLEUROXUS.

principally arising from the curvatui'e of
one margin of each half of the valve ; keel
not median, especially near the ends j ma-
rine; length 1-200" ; striie 75.

StricB longitudinal and transverse (dots
opposite, PL 15. figs. 39, 42).

In most of the following species or forms
the dots are not ec[uidistaut in the longitu-
dinal and transverse rows.

P. strir/ilis (fig. 12). Linear-lanceolate ;
sigmoidiire evident ; keel nearly median,
flexure double ; marine ; length 1-75" ;
striae : longitudinal 40, transverse 36.

P. balticum (fig. 10). Broadly linear,
narrowed at the ends ; sigmoidure apparent
at the ends only and produced principally
by the curvature of one margin only ; keel
not median, flexure double ; marine ; length
1-80" ; strise, both sets, 38. Fig. 39, piece
of valve, showing dots.

(8. Gradually tapering towards the ends ;
striae obscure.

P. Hippocampus (tig. 13). Narrowly
lanceolate, gradually attenuated towards
the broad, very obtuse ends ; sigmoidure
evident ; keel nearly median ; marine or
brackish water ; length 1-lGO"; stritB : long.
32, tr. 40.

P. attenuatum (fig. 15. PI. 1. tig. 17).
Linear-lanceolate, with obtuse ends; sig-
moidure slight ; keel nearl)^ median ; marine
and freshwater; length 1-120"; striae:
long. 30, tr. 40.

P. lacustre (fig. 18). Linear-lanceolate,
ends rather obtuse ; sigmoidure evident ;
keel almost median ; freshwater ; length
1-130" ; striae, both sets, 48.

P. tenuissimmn (tig. 24). Narrowly linear,
attenuate towards the ends ; sigmoidure
evident ; keel nearly central ; freshwater ;
length 1-180" ; strise, both sets, 48.

P. Spencerii (tig. 17). Linear-lanceolate;
sigmoidure evident ; keel nearly median ;
freshwater ; length 1-200" ; striae : long. 55,
tr. 50.

P. littorale (fig. 19). Lanceolate, ends
somewhat prolonged ; sigmoidure evident ;
keel median ; freshwater ; length 1-180" ;
stria) : long. 24, tr. 50, Fig. 42 represents
the dots upon part of a valve.

P. acumiitatum (fig. 14). Linear-lan-
ceolate, acuminate ; sigmoidure evident ;
keel median ; freshwater ; length 1-150'' ;
strite : long. 40, tr. 52.

P.fascioln (tig. 21). Linear-lanceolate;
with linear beak-like ends ; sigmoidure evi-

dent; marine; length 1-200": striae": long.
(?),t;.04. ' ■ o

P. prolongatum (fig. 23). Very narrowly
linear-lanceolate, acuminate, with Hnear
beak-like ends ; sigmoidui-e present in the
ends only ; keel nearly median ; marine ;
length 1-200 ; striae : long. (?), tr. 65.

P distortmn (jig. 20). Lanceolate; ends
slightly produced and beak-like ; sig-
moidure evident ; keel central ; marine ;
length 1-300"; striae: long. 65, tr. 75.
" P. macrum (tig. 22). Very narrowly
linear-lanceolate ; ends produced into long
beak-like processes ; sigmoidure produced
by the ends of the beaks only ; keel median ;
length 1-100"; marine; striae: long. (?),
tr. 85.

BiBL. Hassall, Freshwater Alcjce.^ 435;
Smith, Brit. Diatom, i. 61 ; Kiitzing, Sp.
Al(/. and Bacill. ; Rabenhorst, Aly. i. 230
(46 European species) ; and the BiBL. of

DlATOMACE^.

PLEUROSTAU'RUM,Rab. = Stauroneis
united into tilaraents.

BiBL, Rabenh. Ah/, i. 258; O'Meara,
Qu. Mic. Jn. 1872, 387.

PLEUROT^E'NIUM, Nageli.— A genus
of Desmidiaceae, consisting of species of
Closterium, Docidium, and Penium.

BiBL. Rabenh. Fl. Eur. Ala. iii. 140.

PLEUROT'RICHA, Stein. — A genus
of Hypotrichous Infusoria. Like Stylo-
nychia.1 but vsathout caudal setae, with
larger ventral setfe, and the anal styles in
two groups. 3 species ; freshwater. (Kent,
Inf. 782.)

PLEUROT'ROCHA, Ehr.— A genus of
Rotatoria, of the family Hydatintea.

Char. Eyes none ; a single tooth in each
jaw; foot forked (^ = Hydatina with uni-
dentate jaws).

P. (jihha (PL 44. fig. 18). Body ovate-
oblong, truncate in front ; toes small, turgid.
Freshwater ; length 1-216".

BiBL. Ehr. Infus. 418 ; Gosse, Ann. N.
H. 1851. viii. 199.

PLEUROX'US, Baird. — A genus of
Entomostraca, of the order Cladocera, and
family Lynceidfe.

Char. Anterior part of shell prominent
above, obliquely truncate below ; first pair
of legs very largo ; beak shai'p, cur\ed
downwards. Freshwater.

P. triiioncllus (PL 19. tig. 32). Beak
long, sharp-pointed, slightly curved down-
Avards ; inferior antennae' short and slender,
anterior branch with four seta^, one from
the first joint, one from the second, and two

PLOCAMIUM.

[ 609 ]

PODISOMA.

from the last ; posterior brunch with three
set^, all arising from the last joint.

r. unciiiatus. Beak curved upwards at
the end ; 3 sharp spines at anterior inferior
angrle of shell ; inferior antennae as the last.
P. hamaftts. Beak blunt and strong,
slightly curved downwards ; fir.st pair of
legs with a curved claw at the end. PMale
of P. trigonellus.

BiBL. Baird, Brit. Entomostr. p. 134.
PLOCA'MIUM, Lamouroux. — A genus
of Delcsseriacese (Florideous Algte), con-
taining one species, P. cuccineum (PI. 4.
fig. 10), the commonest of our red sea-
weeds, with a delicate flat feathery thallus,
from '2 to 12" high, growing in bushy tufts
on rocks or other Algae. The fruit consists
of : — 1. coccidia, spherical, stalked or sessile
tubercles, at the sides or in the axils of the
ramules, tilled with angular spores ; 2. an-
theridia, which occur in inconspicuous flat
patches, composed of short erect cells, upon
the surface of distinct plants ; and 3. sti-
chidia, lateral or axillary, simple or branched
pods containing a single or double row of
linear (transversely parted) tetraspores.

BiBL. Harvey, Mar. Alg. 19; Phyc.
Brit. pi. 44; GreV. Alg. Brit. pi. 12; Thuret,
Ann. Sc. Nat. 4 ser. iii. 19.

PLCEO'TIA, Duj.— A genus of Infusoria,
family Thecamouadina.

Char. Body diaphanous, with several
longitudinal ribs or keels in the middle, and
a rounded perfectly limpid margin. Two
anterior locomotive filaments, one flagelli-
lorm, the other trailii:g and capable of
arresting the movement of the body.

P. vitrea (PI. 31. tig. 67). Marine; length
1-1200". Movement slow.
BiBi,. Duj. Infus. 34o.
PLffiSCO'NIA, B\i\., = Eiiphtes, Ehr.
PLUMATEL'LA, Lamk.— A genus of
freshwater Polyzoa, order Hippocrepia,
family Plumatellida?.

Char. Zoary confervoid, branched, tubu-
lar, branches distinct ; tentacular disk cre-
scentic ; ova elliptical, with a marginal ring,
but no spines.

P. repeiis. Zoary irregularly branched ;
cells subclavate, without a longitudinal fur-
row or keel ; tentacles about 60 ; tentacular
membrane dentate ; ova broad.
a. Adherent thrcugho'it.
/8. Attached only at the base.
P. fruticosa. Irregularly branched, at-
tached at the origin only ; cells cylindrical,
and destitute of furrow, but obscui-ely
keeled ; ova elongated.

P. coraUoidcs. Attached at the base only ;
tubes dichotomous, densely tufted, desti-
tute of furrow and keel ; tentacles about
60 : ova broad.

liiBL. AUman, Freshio. Pohjz. 92 ; Ann.
X. 11. 1844, xiii. 330; Johnston, Br. Zooph.
402; Parfltt, Ann. N. H. 1866, xviii. 171.

PLU.AIULA'RIA, Lamk.— A genus of
Hydroid Zoophytes, family Plumulaiiidic.

Char. Polypidom plant-like, rooted, sim-
ple, or branched, feathery ; cells small, uni-
lateral, usually seated in the axilla of a
horny spine ; egg-vesicles scattered. Ten
British species.

P. cristata. Stem simple, a single tube,
pinnate; pinnae alternate; cells close, rim
toothed ; vesicles gibbous, girt with crested
ribs.

P.falcata. Stem a single tube, -waved,
branched, branches alternately pinnate ;
cells close, shortly tubular, rim entire ; egg-
vesicles oval-oblong; common.

In P. mgriophyllam & P. frutescens, the
stem consists of several parallel tubes.

P. pinnuta, Linn. Stem a simple tube,
plumose; pinnae alternate, three on each
internode ; cells rather distant, campanulate,
appressed, rim entire ; vesicles pear-shaped,
rim toothed.

P. setacea, Ellis. Stem a single tube,
pinnate ; pinuse alternate, one at each joint ;
joints ringed ; cells very remote, campanu-
late, rim even ; vesicles elliptical, smooth ;
common.

BiBL. Johnston, Br. Zooph. 89; Hincks,
Hyd. Zooph. i. 294.

■PLUMULARI'ID.E.— A family of Ily-
droida.

BiBL. Hincks, Hijd. Zooph. i. 279,

PODAXIXE'L— A family of Gastero-
mycetous Fungi, none of which are found
in Britain ; they are distinguished from all
allied tribes by a solid column in the centre
of the sporange.

Many of the species grow on the hills of
the White Ant.

BiBL. Montague, Ann. Sc. Nat. 2. xx.
69; Tulasne, Ann. Sc. Nat. 3. iv. 169;
Currev, Linn. Tr. xxvi. 288.

PODISO'MA, Link.— A genus of Uredi-
nei (Hypodermous Fungi), growing upon
the living leaves and branches of species of
Juniper ; the filamentous mycelium creeping
beneath the epidermis, and sending up a
fleshy, stalk-like, tremelloid body (tig. 589),
composed of agglutinated tilaments (fig. 590)
terminating in bilocular spores (or two
spores adherent together), each of the cells

2k

rODOCORYNE.

[ GIO ]

PODOSPIIEXIA.

having two or four pores, throng-li wliicli
the internal membrane is protruded in ger-
mination.

Fig. 589.

Fig. 690,

Podisoma Juniperi.

Fig. .589. Branch of Juniper with clavate fructification
protruded from beneath the bark. Nat. size.

Fig. 590. Vertical section through a fruit, sliowing
the fllamenta terminating in bilocular spores. Magnified
50 diameters.

Four species are descrihed as British : P.
Juniperi-comimmis, P. Jun-sahince, P.folii-
cohim (on the leaves of J. communis), and
P. fuscum on Pinns halepensis and oxy-
cednis.

It has been supposed, but perhaps -with-
out sufficient grounds, that the Podisoma
of Savine is a condition of Rastelia cancel-
lata.

PODOCOR'YNE, Sars. — A genus of
Hydroid Zoophytes. 2 species j on stones
and shells, deep water.

BiBL. Sars, Fmin. Lift. Now. i, 4, t. i. ;
AUman, Ami. N. H. 1859, 1864 ; Ilincks,
Hyd. Zooph. 27 ; Agassiz, Sea-side Studies,

1871.

PODOCOPtYN'IDyE.— A family of Hy-
droid Zoophytes.

Char. Polypes sessile, with a single
whorl of filiform tentacles around the base
of a conical proboscis ; mouth simple. Gen. :
Podocoryne and Conjnopsis.

BiBL,. Hincks, Hyd. Zooph. 27.

PODOCY'ATHUS,Kt.— LikePof/op/^T/o,
hut with two kinds of tentacles, prehensile
and suctorial. P. diadema, marine, length
1-600", (Kent, Inf. 827.)

PODOCYS'TIS, Ktz.— A genus of Dia-
tomacete, Cohort Surirelleaj.

Char. Frustules sessile, cuneate ; valves
convex, obovate, with a median line, trans-
verse continuous, and intermediate granular
strife.

P. americana, Bailey (PI. 51. fi^. 7).
The only species ; marine = P. adrintica,
'Kiz.= Doryphora elcyans, Roper.

BiBL, Bailey, Smith. Contr. 1854 ; Ktz.

Bac. 62 ; Roper, Mic. Jn. ii. 284 ; Rabenht,
Aly. i. 60.

PODOCYS'TIS, hiy. = 3Ielampsora. See
Uredinei.

PODODIS'CUS, Kg.— A genus ofDia-
tomaceae.

Cliar, Frustules single or concatenate,
with a marginal stalk ; valves circular, con-
vex. Marine. No markings visible under
ordinary illumination.

P. jamaiccnsis (PI. 17. fig. 16). Stalk
elongate, weak. Diameter 1-840",
BiBL. Kiitz. Baeill. 51 ; Sp. Aly. 26.
PODOPH'RYA, Ehr.— A genus of Aci-
netina.

Char. Suckers simple, capitate, in bun-
dles or on the surface, neither on a trunk
nor ramified; body without a shell, pedun-
culated. Several species, freshwater and
marine; P.fxa (PI. .30. fig. 5, a k b).

BiBL. Ehr. Inf. 305; Clap, et Lach. Inf.
.381; Kent, Inf. 813; Gegenbaur, Moiph.
Jahrh. 1875.

PODOSI'RA, Ehr.— A genus of Diato-
macefB.

Cliar. Frustides concatenate, with a la-
teral stalk; valves circular, punctate, con-
vex. Marine. Stalk attached to the centre
of the valves.

P. hormoides (PI. 19. fig. 34). Frustules
2 to 6, depressed-spheroidal, connected by
isthmi or stalks ; hoops obscurely punctate.
Diameter 1-650".

P. Montaynei (Melosira ylohifera, Ralfs),
Frustules usually .2 ; hoops striate, Diam,
1-600",

P. maculata. Smith, Diat.
P. compressa, West, Prifch. Inf. 815.
P. I(^ris, Gregorv, Mic. Jn. vii. 85.
BiBL. Kiitz. Sjp. Alg. 26; Smith, Br.
Diat. ii. 53 ; Rabenh. Ah), i. 37.

PODOSPHE'NIA, Ehr.— A genus of
Diatomacese.

Char. Frustules attached, sessile, wedge-
shaped in front view ; ends indented so as
to produce a black line (vitta) in the front
view ; valves convex, obovate, with a lon-
gitudinal median line and transverse strise,
but no nodules. Marine.

The strife consist of rows of dots, some-
times distinct by ordinaiy illumination, at
others not so.

P. Ehrenheryii (PI. 17. fig. 17). Frus-
tules truncate at the end in front view ;
valves somewhat acute at the ends ; length
1-240".

P. Lynyhypi. Fr. truncate in front view ;
valves rounded at the end; length 1-350".

rODOSPORIUM.

[ Gil ] POLARIZATION OF LIGHT.

Three otlier British species.

BiBL. Smith, Br. Diat. i. 82; Kutz.
BacilL 119; Rabenhorst, Alff.i. 110.

RODOSPORIUM, L^T.,= Mdamj^sora.
See Uredixei.

PODOS'TOMA, Clap, et Lach.— A genus
of Amoebasa (Rhizopoda).

Char. Bodies amoeboid, with 2 kinds of
pseudopodia, one the ordinary, the others
teriuiuitin';- in a llapellum.

P.filujerum, among aquatic plants.

Bi"i!L." Clap, et Lach. Inf. 441 ; Kent,
//;/•. ■2-2i.

"PODU'RA, L. — A genus of Insects, order
Thysauuiu, family Podurellse.

The original genus has been greatly sub-
divided. In its extended signification, the
characters consist in tlie thorax being di-
stinct from the abdomen, and in the presence
of a forked tail, bent under the abdomen
when not in use, and enabling the animals
to move by springing or jumping, whence
the common name of spring-tails applied to
them.

They are of a leaden appearance, and
found in shady damp places, as under flower-
pots or stones, in cellars, &:c., and are about
1-20 to 1-10" in length. They may be
caught by placing a little flour upon a
piece of paper in their haunts.

Fig. 591.

i \

I'odura.
Magnified, about 15 diameters.

The body is covered with scales (PI. 1.
fig. 12), which are used as test-objects.
Those of the so-called P. j^^umbea, which is
now described as a Lejnduqirtns, are usually
recommended ; but the most common Po-
dura is not this species. This, however, is
a matter of little importance, because the
scales of several species, belonging to even
different genera, are similar both in form
and markings.

See Scales of Ixsects and Test-
objects.

BiBL. Gervais, Walckenaer^s Apteres, iii.
and the Bill. ; M'Intii-e, Mn. Mic. Jn. i.

203 ; 1870, 1 ; Beck, Mic. Tr. 1802, 84 ;
Lubbock, Thi/snnura, Bai/ >Soc.

PODURlilP'PUS, Megn.— A genus of
Thysanura, fam. Podurelhc. P. piti/riaaicus ;
body fusiform, black, legs paler ; producing
prurigo in horses. (Megnin, Paras. 104.)

PLEUROCIllLID'IUM,Steiu.— Agenus
of Ilolotrichous Infusoria. Free, no cara-
pace, sidjreniforui, mouth with a narrow
undulating membrane. P. striyilatuni,
among Leinnce. (Kent, Inf. 540.)

POLARTSCOPE.— A term employed to
designate a polarizing apparatus, consisting
of a polarizer and analyzer. See Intro-
duction, p. XX.

POLARIZATION OF LIGHT.— The
phenomena exhibited by microscopic ob-
jects, when viewed by polarized light, are
perhaps the most beautiful and interesting
of those connected vvdth the use of the
microscope. The extreme brilliancy, trans-
parency, and variety of the colours deve-
loped cannot be equalled ; much less can
they be represented by illustrations, although
the figures in PI. .39 may give some idea of
the manner in which they are arranged in
certain objects.

The ordinary arrangement of the parts of
the polarizing apparatus scarcely needs de-
scription,— the polarizer being placed be-
neath the object and the analyzer above it,
the polarizer and analyzer usually consisting
of two Nicol's prisms, although two plates-
of tourmaline are sometimes used. Some
artificially prepared crystals exert a power-
ful polarizing action, and may be used either
as polarizers or analyzers, or as both ; among
these the salt of Quinine called Herapa-
thite occupies the first place. Others form
interesting analyzers, some of which have
been noticed under Analytic Crystals
and DiCHROisii.

Numerous salts and other crystalline
bodies, which powerfully depolarize the
already polarized light, and exhibit beauti-
ful colours, are mentioned under their re-
spective heads ; some of these may be enu-
merated here^as the oxalate of ammonia,
of soda, and of chromium and ammonia,
the oxalurate of ammonia, the acetate of
copper, chlorate of potash, the prismatic
form of the ammonio-phosphate of mag-
nesia, the ammonio-phosphate of soda, the
sulphates of cadmium and of magnesia,
selenite, salicine, fused sautouine, uric acid,
&c.

Many animal bodies and tissues also
possess considerable depolarizing power, and

2r 2

POLARIZATION OF LIGHT. [ G12 ] TOLAEIZATIOX OF LIGHT.

form 'beautiful microscopic objects — as
horse-hair, portions of feathers, sections of
quill, of hoof, horn, fish-scales (salmon),
&c.

The influence of vegetable structures on
polaiized light has been thoroughly investi-
gated by Mohl, whose interesting accoimt
■we are able to confirm, and a brief notice of
it is desirable here; but the observations
apply equally to the more feebly anisotro-
pous tissues of animals. As it is desirable
to obtain as much light as possible, a glass
prism is prefei-able to the ordinary mirror
for illumination ; Nicol's prisms are bettor
than tourmaline or Herapathite for the pola-
rizer and analyzer ; and the latter should
be as large as possible. Further, the hght
emerging from the polarizer should, if
possible, be condensed by an achromatic of
large aperture ; or the condensation may be
etfected by a hemispherical fiint-giass lens,
5 lines in diameter, having its plane face
turned towards the object. The obj ct-
glasses must be of large angular aperture ;
a power of 4-10" is sufhcient for most
objects; but 1-4", and even 1-8" object-
glasses may be made to transmit sufficient
light. It is requisite to provide plates of
the doubly-refracting substances mica and
gypsum, mounted so that they can be in-
serted between the polarizer and the con-
denser, and revolved horizontally while so
placed. Those of mica are used for de-
tecting weak degrees of doubly-refracting
power, being of such thickness as to give a
grey field with a white or black object
when the prisms cross. The thin laminae,
of which six may be provided, from the
thinnest possible 'up to 1-20"', should be
cemented with Canada balsam between
glass plates. For obtaining colours, plates
of gypsum, similarly mounted, are best.
Mohi prefers such as give a red field, and
provides plates of diflerent thickness, giving
the reds of the different orders of Newton's
rings.

it is easy to ascertain whether an organic
body shows positive or negative colours,
by comparing its colour, when seen with a
plate of gvpsum in a certain definite posi-
tion, with the colour given under the same
circumstances by a strip of glass brought
into a state of tension by slight bending, or
with the colours of a suddenlj'-cooled glo-
bule of glass. In this way the author de-
termined that the fibres of a spiral vessel
displayed negative colours, and the laminpc
of a starch-corjuiscle positive colours, and

then applied these organic structures, by
comparison, for ascertaining the properties
of other objects. The objects to be exa-
mined should be mounted in a liquid or
other substance rendering them as trans-
parent as possible, such as glycerine, Canada
balsam, or an essential oil.

"When ordinary globular or cylindrical
cellular tissues are viewed by cross sections,
their substance is seen to be doubly refrac-
tive; for when the prisms cross, the circular
sections of the cell-walls appear like rings
of bright light on a black ground, but with
the ring divided into four quadrants hj dark
stripes, as if a black cross lay over it; when
the prisms are placed parallel, the parts of
the section previously bright appear dark,
and vice versa, on a bright field. If a sec-
tion of polyhedral cellular tissue is viewed
in the same way, the appearances are
somewhat different, since the cut edges
are here straight lines, variously inclined
towards the prisms ; those which are per-
pendicular to the prisms are invisible,
while those standing obliquely are bright
in their whole length. In general, cell-
membrane acts more powerfully on the
light the denser its substance, and soft col-
lenchymatous tissues are far less powerfully
doubly-refractive than wood-cells. When
the cells have the walls much thickened, it
is common for the primary cell-membrane
to be much more powerfidly refractive than
the secondary layers. The influence of cel-
lulose membranes upon polarized light is
not much affected by bleaching them with
nitric acid and chlorate of potash (Schultze's
reagent). It has been supposed that the
remarkable eifect produced by the epidermis
of Equisetum hyemale is attributable to the
silex present ; but Mohl finds the action
greatly weakened by destroying the organic
matter by a red heat. But this heating
does not remove the power there, nor in
the Diatomacese, of which Mohl confirms
Bailey's statement, in contradiction to Eh-
renberg, that various species of Kavicula,
St/nedra, Pknrosif/ma, and Melosira are de-
cidedly doubly refractive.

Very remarkable phenomena are pro-
duced when the polarized light is made to
pass through plates of mica or selenite. In
the first place, thin plates of mica often
allow of the discovery of a doubly-refracting
power too feeble to be detected bv the
prisms alone — the degree of illumination of
the object being slightly different from that
of the field on which it is viewed. But the

POLARIZATION OF LIGHT. [ G13 ]

POLLEN.

most important matter is the revelation, by
the use of the selenite plates, of the exist-
ence of positive and negative characters,
like those of positive and negative crj-stals,
in the chemically distinct constituents of
vegetable tissues.

Let us suppose that between the lower
prism and the object is placed a plate of
selenite giving a red field ; the plate is then
rotated so that its neutral axes are at an
angle of 45° with the prisms. A section
of a cylindiical vegetable cell will be seen
to be divided into four quadrants : the two
alternate quadrants, whose middle lines cor-
respond to the neutral axes of the selenite,
are either blue or green, the other two
yellow or red : if the selenite is then rotated
so that its neutral axes are perpendicular to
the prisms, the colours will be all lost ; but
on continuing the rotation, they reappear in
the reverse order — what was blue appearing
yellow, and vice versa. When the walls are
rectilinear, all the ceU-walls perpendicular
to one of the prisms will give the colour of
the field, all those which run parallel with
one of the neutral axes of the selenite plate,
or form no great angle with it, will be blue,
those parallel with the other axis yellow.

It is found that vegetable structures fall
into two classes in reference to these colours,
in one of which classes all layers lying ob-
liquely in the direction of a right-wound
screw are tinged blue and yellow, those
oblique in the opposite direction yellow or
red ; in the other class, the colours under
the same conditions are just the reverse ; so
that one class are optically positive, the
other optically negative.

The optically negative are the ordinaiy
cell-membranes of the internal organs of
plants, whether in their natural condition
or cellidose purified by the help of nitric
acid and chlorate of potash : collenchyma,
horny endosperm-cells, the gelatinous ceUs
of Algae, &c., all agree in this property.
Optically positive colours are given by cell-
membranes of periderm and the cuticular
layers of epidermal cells. The contrast of
the positive and negative colours of the
cuticle and other parts of the cell-wall is
well seen in the epidermis of Aloe. The
diversity of colouring under polarized light
here corresponds to the diverse behaviour
under treatment with iodine after macera-
tion in solution of potash (Secoxdary
deposits).

The longitudinal sections of all behave
like the cross sections j but the appearances i

are not so clear. When side views of the
surface of cells ai'e obtained, the phenomena
are very varied ; but these are best seen in
vessels or ducts when the thickening layers
are in the form of spiral bands. Tluis, if
one of the spiral vessels of Musa is placed
(its spiral somewhat drawn apart) with its
long axis perpendicular to one of the prisms,
the fibres on the upper side turn to the left,
those on the under side towards the right ;
and when the selenite plate is interposed,
they exhibit the complementary colours.
When the side walls of cells have obscure
striation, as in the cells of Conifers, the
liber-cells of Apocyneas, kc, the membrane
gives evidence of its fibrillar structure by
the yellow or blue colour developed with
the selenite plate. If fibres of a spiral
vessel cross at right angles, and they are
pressed together, they neutralize one another
where they cross : when the prisms are
used alone, the crossing points are black,
the rest of the fibres white ; when the
selenite plate is interposed, the crossing
points exhibit the colour of the field, and
the uncrossed portions of the fibre are blue
or yellow according to position.

The vicinity of a round bordered pit, as
in the wood-cells of Finns, exhibits a black
cross when seen perpendicularly by polarized
light. The black cross and the colours ex-
hibited by starch are well known. Chloro-
phyll does not seem to act on polarized
light, nor the primordial utricle of cells,
except a trace when contracted by weak
alcohol.

The polarization apparatus is exceedingly
useful for the detection of ciystals (Raphi-
DEs) in vegetable tissues, when thej'^ are so
small as to be easily overlooked ; and the
larger kinds form beautiful objects with,
and often without the selenite plate.

BiBL. Herschel, Encycl. Metrop. art.
Light ; Pereira, Lec-t. on Pol. Light, hy B.
Powell; Brewster, Optics; Erlach, Beobacht,
iib. organ. Element, bei polar. Licht, Miiller's
Archiv, 1847; Valentin, Untersuch. 1801;
Lobb, Qu. Mic. Jn. viii. 107; Carpenter,
The Microscope ; Beale, How 8fc. ; JDavies-
Matthews, Mounting ^-c.

POLLEN.— This name is applied to the
coloured pulverulent substance familiar to
every one as occurring scattered in the in-
terior of full-blown flowers ; it is produced
in the anthers, the (usually) stalked club-
shaped organs which stand in one or more
circles between the floral envelopes and the
pistils, and is discharged from them when

POLLEN.

[ 014 ]

POLLEN.

ripp, in order to fertilize the ovules. When
slightly magnified, the pollen of most
flowers appears to consist of granules, of
different size and colour in different plants ;
hence the individual particles are called
poUen-c/rains or cjrcmulcs (PI. 40). Exami-
nation under a sufficient magnifying power
shows that the simple or typical forms of
pollen-grains are single free cells filled
with fluid matter: more complex forms
occur in many cases, which, however, may
he simply characterized as simple pollen-
grains, permanently coherent into defiriitely-
formed groups.

The pollen-grain may be examined as to
its form and stucture, its contents, and its
development.

The forms of simple grains presented in
dift'erent plants are tolerably varied — sphe-
rical (PI. 40. figs. 8-10, 22, 23, 25) and
elliptical (figs. G, 11, 29) being perhaps
those most common ; but besides these, nu-
merous geometrical forms occur, such as
tetrahedral (fig. 14), polygonal (figs. 16, 27,
28), cubic (fig. 19). But it must be noted
here that the forms frequently vary accord-
ing as the pollen is viewed dry or in fluid,
since the elliptical and allied forms often
expand into a spherical form, when they
absorb liquid (figs. 18 & 20 a, h, c). The
explanation of this will be given presently.
The external appearance is further greatly
influenced by minor peculiarities of form,
such as ridges, spines and processes of dif-
ferent kinds ; these, however, are referable
to the structure of the outer coat.

The ordinary structure of the coats or
the cell-wall of the pollen-grain is that of
a delicate internal cell-membrane, with an
outer, thick and resisting layer, which may
be regarded as the Cuticle of the inner or
proper membrane of the cell. In a few
cases the inner membrane alone exists, as
in the cylindrical pollen-cells of Zostera
and some other aquatic plants. In other
cases the outer or cuticular coat presents a
more complex structure, and two, or, it is
said, even three layers may be distinguished
in it ; these, however, seem to be merely a
lamination of the outer coat. The condi-
tions in some of the Coniferas are dift'erent
from this, and will be alluded to presently.
The inner membrane is exceedingly deli-
cate and homogeneous: in ordinarj- spherical
or oval grains it accurately lines the outer
coat ; in some of those forms which present
processes of various kinds, kucIi as (linothera,
it seems to us that the inner coat does not

extend into these processes in the mature
pollen. The outer coat exhibits, as to sur-
face, ever}' variety of appearance, from
smooth, through granular and spiny, to
pseudo - cellular arising from reticulated
ridges ; in addition to this, the ju'ocesses
just alluded to give a very peculiar aspect
to many kinds of' pollen. Besides these, we
find in all cases markings appearing like
pores, or others like slits (which become
furroxvs when dry), or both together, and
these in varying niunber iii diflereut cases.
The colour of the pollen presents great dif-
ferences ; although usually yellow, it may
be Avhitish, red {Vcrbascum) , blue {Epilo-
bimn cnicjustifoliinn), even black (tulip) : this
colour resides in the outer coat. The outer
coat also exhibits, in the majority of cases,
a secretion upon its surface, of a viscid cha-
racter, usually described as oily, biit appa-
rently consisting of a viscid matter not
readily soluble in water, remaining from
the dissolved parent cells. It would seem
to be the substance which holds together
the poUen-grains in those cases where it
consists of waxy masses, readily breaking
up into small fragments (Ophrydeous Or-
chids). In the Onagracefe the pollen-grains
are loosely connected by slender viscid fila-
ments, which appear to be derived from
the same source.

The more detailed explanation of the
character of the pores &c., the projecting
processes, and the compound conditions of
pollen will be understood better after a
sketch of its development.

The anther, in which the pollen is formed,
consists in its yoimger stages of a minute,
solid, cellular papilla or c_\lnidrical body.
At an earlv period a distinction becomes
manifest in its cells : a single vertical row,
lying in the position of the axis of each
pollen-chamber (or loculus), presents a
different aspect, from its cells exceeding the
surrounding ones in size ; and these rows
undergo a special development to produce
the pollen-grains, while the surrounding
layers are developed into the tissues forming
the coat or wall of the anther, and its mid-
rib or connective (see Akther). The cells
of the primary row multiply by cell-division
with the general increase in size of the
anther (figs. 592-594), until at length they
form relatively large masses of cellular
tissue composed of large squarish cells
filled with granular contents, well defined
as constituting a distinct tissue from the
walls of the pollen-chambers. A new

rOLLEN.

[ G15 ]

POLLEN.

CI

Fig. 592. Fig. 59,3.

C.E CE CI CM

Fig. 594.
CL Ci CM

Tertical secfions of a cell of a Tonrg anther of the
Melon, showing the gradual separation of the regions.
C E, epidermal cells; CI, cells of the wall of the anther;
CL. cells lining the loculi ; CM, cells from which the
pollen is developed.

Magnified 100 diameters.

change then takes place : the contents of
each cell secrete a layer of cellulose, which
does not adhere to the wall of the parent
cell to form a layer of secondary deposit,
but lies free against it, so that a new free
cell is foiTued -vN-ithin each old one, nearly
tilling it. The walls of the old cell (form-
ing a connected parenchymatous tissue)
then dissolve, so that the new cells be-
come free, no longer merely in their parent
cells, but in a cavity which is to constitute
the pollen-chamber or loculus of the anther.
These free cells are the parent cells of the
pollen of authors. A new phenomenon soon
occurs in these. These parent cells divide
into four by ordinary cell-division, either
by one or by two successive partings by
septa at right angles to each other but both
■perpendicular to an imaginary axis (as when
an orange is quartered), or by simulta-
neously-formed septa which cut off por-

tions in such a manner that the new cells
stand in the position of four cannon-balls
piled into a pyramid (tetrahedrally ). These
new cells are the special parent cells of the
pollen ; and in each of these the entire pro-
toplasmic contents secrete a series of layers,
which in the ordinary course, by the solu-
tion of the primary walls of the special

Fig. 595.

Fig. 597.

Fig. 596.

Pollen-grain of the Melon in various stages of de-
velopment.

Magnified 100 diameters.

parent cells upon which they were applied,
become the walls of free cells, which con-
stitute the simple ordinary pollen-cells.
These subsequently increase in size ; and
their outer laminae assume the characteristic
form and appearance while free in the
chamber of the anther (figs. 595-697).

In referring the peculiarities of many
kinds of pollen to circumstances connected
with the development, it may be noted in
the first place, that the mode of division of
the parent cells into quarters often influ-
ences the ultimate fonn of the pollen-grain :
thus, when the division is by two planes at
right angles, the original form of the pollen-
grain will be elongated, and the ripe grain
will probably be elliptical, while, when the
division is " tetrahedral," the grains may
retain the form thus produced, or be slightly
modified and become polygonal, or, as is
more common, they expand more readily
than the others into a sphere. But there is
no absolute rule here ; we find even the
tetrahedral and the polar division occur
together among the parent cells of the same
anther. In the next place, a compoimd
condition of the pollen-grains (PI. 40. figs.
7, 17) is readily explicable by referring it to
an arrest of the process of subdivision ; so
that if the walls of the special parent cell
do not dissolve, the pollen-grains will be
left in groups of four ; and if the parent
cells do not become singly detached in the

POLLEN.

[ 616 ]

POLLEX.

antecedent process of solution, tlie grains
maj- be still developed in the same order
and manner and remain connected in greater
or smaller masses or groups, each enclosed
in its special parent cell, itself connected
■w ith a number of others of the same gene-
ration by the persistence of the Avails of the
cells in which the parent cells were deve-
loped. This explains the compound pollen
of the Acacias (PI. 40. fig. 25), and, as an
excessive form, the waxy pollen-masses
which occur in the Orchidacese and Ascle-
piadacefe. It is sometimes stated that the
pollen-grains of these compound forms are
merely connected together by the viscid
substance remaining from the solution of
the parent cells ; but this would render such
cohesions indefinite in character, instead of
being regular; at the same time it will be
understood that the solution may have ad-
vanced so far that the grains merely hold
together slighth', and may readily be sepa-
rated. This is not the case, however, with
the majoiity of compound pollen-grains.
When pollen-grains do become free, the
viscidity of their surface is probably refer-
able to the dissolved parent cells.

The metamorphoses of the outer coat or
cuticle of the pollen-grain are very remark-
able, and not yet at all understood ; the
granulations (PI. 40. figs. 11, 12), spines
(tigs. 8, 9, 22, 26), reticulations (figs. 13, 23,
27, 28), &c. characterizing mature grains
make their appearance in the interval be-
tween the solution of the special parent
cells and the bursting of the anther, while
the pollen-grains lie free within the latter ;
their production is accompanied by a gene-
ral growth and expansion of the pollen-
grain. AVe have observed that the outer
coat is often deposited as a very thick layer
inside the special parent cell, and that, when
the latter dissohes, the outer coat of the
pollen-grain is also in a softened condition,
and becomes stretched by the expanding
inner coat, finally forming a comparatively
thin layer on the ripe grain {e. g. in Tra-
descantia). The mode of origin of the
markings, like those on Spores and on the
cuticle oi Helk'bo7-its &c. (see Epideemls),
is altogether unknown ; probably all the
cases are referable to one cause.

It has been mentioned that the u re
pollen-grain exhibits pores or slits. • We
believe they should rather be regarded as
thinner places in the outer membrane. Their
number and position varies much, as will
be indicated presently on referring to some

of the principal types of form of pollen.
The slit-like markings are generally ac-
companied by a peculiar shrinking of the
p;)llen when di'y, the coat collapsing at
the thin places, so that gi-ains of this
kind appear oval or angular, not clearly ex-
hibiting the slits (which then become fur-
7'otvs) ; but they swell out and display the
latter clearly when placed in water or di-
lute acids (PI. 40. figs. 18 & 20). AN'hen
the so-called pores exist, they are either
like simple pores (PI. 32. fig. 10), or they
may be provided with little disk-like pieces
or lids, which fall off" and leave them bare
when the pollen-tube is formed (figs. 13 &
22). In all cases, however, we believe that
the outer coat is extended over the whole
surface, and that the slits and dots are
merely thinner places ; moreover, in certain
cases (^Leschenaultia, a quatemate pollen)
we have seen the thickening layers of the
young pollen-grain, inside the parent cell,
exhibit iiits (exactly comparable to those of
ordinary pitted cells) at the places corre-
sponding to the future pores, and, curiously
enough, in some cases at least, the pits of
adjacent pollen-cells corresponding, although
in the mature expanded compound grains
they were far separated. Sometimes the
lids are found at the end of short projecting
processes (PI. 40. fig. 22). The pollen of
GEnothera and allied genera exhibits remark-
able conditions, which have been mistakenly
described. The form of the grain is that of
a depressed sphere with three large equi-
distant truncated cones projecting pretty
nearly in the same plane. The outer coat
is thick, except at the ends of the couical
masses; and two laminoe are distinguishable
(PI. 40. fig. 14). The outer coat thins oiF
towards the end of each process. It ap-
pears to us that the inner coat or true
pollen-membrane does not extend into the
processes at all, but is globular, and that a
semifluid deposit occupies the space between
the inner coat and the outer, in the cavity
of the tubular processes. Now, supposing
such a deposit to become hai-dened and,
after circumscissile fission, pushed oft" as a
plate by the advancing pollen-tube, instead
of giving way and expanding, we should
have the lid occurring in Cncitrbita Pepo
(PI. 40. fig. 22) and other cases.

Is has been stated that the pollen is the
agent of fertilization of the ovules in the
^'lowering plants. When scattered from
the anthers, that portion of tlie pollen
which falls upon the stigma (and frequently

rOLLEN.

[ 61^ ]

POLLEN.

other portions fiilling upon nectaries or
secreting surfaces) swells slightly, and ger-
minates a,^ it were, sending out a delicate
tubular process from one or more of the so-
called pores or slits (PI. 40. fig. 30), which
processes (the poUen-tnbes) insinuate them-
selves between the loosely packed cells of
the stigma, and, eontirnially elongating,
make their Avay down the style and along
the conducting tissue to the ovules. In the
Conifer;^ the pollen-grains fall directly upon
the micropyle of the naked Ovule, and
send their pollen-tubes into it. The pollen-
tube is produced by the development of the
inner or proper coat of the pollen into a
tubidar filament. When pollen-grains are
placed in dilute sulphuric acid or in syrup
(sometimes in water), they absorb liquid,
swell, and their contents partly exude from
pores kc, either to a slight extent, as a
little "hernia," as it were, of the inner
membrane, or in large quantity in a worm-
like, irregular mass ; in the latter case the
coagulation of the suiface often produces a
pellicular coat. These exuded masses are of
course distinct from the true pollen-tubes
produced under natm-al conditions.

The fluid contents of the pollen-grains
consistof agranular viscid protoplasm, with
minute starch-granules and (apparently)
oil-drops, making together what has been
called the fovilla, which increases in density
as the pollen ripens. The starch-granules
exhibit molecular motion in the pollen-
tube, and still more clearly when they
escape by rupture. The granular contents of
the pollen-cell, which are always rendered
opaque by the action of water, are gi-adually
transferred to the pollen-tube as it elongates.

Connected witii this point is the pecu-
liarity exhibited by the pollen of the Coni-
ferse. In the Abietineas the form of the gra-
nules is very peculiar — elongated, curved,
and with bulging ends ; and, according to
Schacht, a distinct internal ceil exists, at-
tached at one side in the cavity of the ordi-
nary pollen-cell, this internal cell dividing
and growdng out as the pollen-tube when
the pollen-grain comes upon the o%nile.
The pollen of the Cupressinese is spheroidal ;
but free cellules appear to be formed in the
pollen-tubes during the fertilization. These
conditions, which are not yet satisfactorily
cleared up, indicate a relation to the sper-
matozoid-producing spores of the Marsilea-
ce*, «S:c., analogous to that between the
Gymnospermous ovules and the ovule-.spore3
of those Ciyptogamic families.

It has been imagined tiiat the form and
structure of the pollen-grains might have
some relation to the general structure of
the plants, and miglit serve as an indication
of systematic position and afllnities. J'ut
there appears to be no definite relation ;
very varied pollen occurs witiiin the limits
of the same family, and very similar pollen-
grains in families widely distant. There
appears, however, to be a certain relation
within the limits oi yenfrn. It may be per-
haps generally .stated that the Monocotyle-
dons have frequently one pore or furrow ;
the Grasses often three pores, as is the case
with many Dicotyledons, many of which
have more, while a large number of the
families of the latter division exliibit both
pores and slits. As microscopic objects, it
is most convenient to class the f(jrms arti-
ficially, or according to structure ; and we
give a brief list of the principal varieties
arranged under this point of view.

The pollen-grains of Zostera, ZanicheUia,
and other submerged aquatio plants, have
no cuticle or outer coat ; all other known
forms possess one or more outer layers.

A. Outer coat without furrows or pores.

a. Outer coat granular: Strelitzia Rer/ince,
CalJa palustris, Crocus sativus, ^-c.,
Asarum europceum, Laurus nohilis, ^-c,
many Euphorbiaceae.

b. Outer coat with papillae : Canna inclica.

c. Outer coat with cell-like reticulations :
Huellia formosa (PI. 40. fig. 2.3;, R,
strepens, Tribulus terrestris.

In Periploca (p-feca (PI. 40. fig. l-o) and
Apocynum vcnctum (fig. 7) grains of this
kind are connected in fours in one plane ;
in some Luzulce tetrahedrally.

B. Outer coat presenting longitudinal fur-

rows (or folds).

* One furrow (the form of most Mono-
cotyledons).

a. Outer coat finely granular : common
in Monocotyledons ; among the Dico-
tyledons, in Myricu ccrifcra, Maynolia
yrandijlora, Liriodendron tulipiferunij

b. Outer coat granular, spiny : Nymplusa
alba.

c. Outer coat with cell-like reticulations :
Hemerocallis fulva, and other Munoco-
tvledons.

POLLEN.

[ 618 ]

POLLEN.

d. Outer coat with irregular reticulations :
Alstrameria C'urtisiana.

Among tlie Orchidese are found quater-
nate grains belonging to this group.

** Outer coat with two furrows : a rare
form, occurring iu species of Fonte-
deria and Amaryllis, Tamits commu-
nis and elephaniipes, Tigridia paw-
nia, Calycanthus JluriduSj &i'c,

*** Outer coat with three longitudinal
furrows.

a. Outer coat granular. One of the com-
monest forms : Quercus Rohur, Viola
odorata (PI. 40. tig. 6).

h. Outer coat with short spines : Cactus
Jiayelliformis, Viscum cdbum.

c. Outer coat with cell-like reticulations :
Statice (PI. 40. fig. 29), various Cruci-
ferse.

**** Outer coat with more than three
furrows.

a. Four : very rare as normal, Hoiisfonia
cccrulea, Cedrela odorata; occasionally
occurring where three is the normal
niimber, as in Solamnn tuberosum.

b. Six : some of the Labiata? and Passi-
florefe (PI. 40. fig. 20), Ephedra dista-
chya, Heliotropium grandlflorum.

c. A large number of furrows : many
Ptubiacefe, e. g. Sherardia arvensis (PI.
40. fig. 18).

The pollen of the Pines is related to this
group, also that of Nymphd'a Lotus, Victo-
ria reyia, and other plants, where the fur-
rows or thin places occupy the greater part
of the wall, and the outer coat forms only
segmental pieces. In Thunbcryia alata
(PI. 40. fig. 24 a) a remarkable appearance
arises from the furrows running in a curved
or spiral direction.

C. Outer coat with pores.

* A single pore : Grasses, Sedges, Ttj-
pha anyustifolia, Sparyanium ra-
mosum.

** Two pores : Colchicum, and a few
other Monocotyledons^ also JJrous-
sonetia.

*** Three pores.

a. Outer coat granular : Dipsacero, Urti-
caceaj, Onagraceae [here the pores form
projecting processes (PI. 40. fig. 14) ;

and in Mori?ida pet'sica this is still more
the case] ; Cucimm satirus.

b. Outer coat with cell-like reticulations :
many Passiflorere — with large lids, P.
cccrulea (PI. 40. fig. 13), alata, ^-c.

**** Four pores.

a. Pores on the equator : Pistacia tere-
binthus, Campanula rotundifolia, ^c.

b. Pores not equatorial : Passijlora ker-
mesina, Impatiens Balsamina (PI. 40.

fig. 21) {Noli-me-tanyere).

***** More than four pores.
t Distributed regvilarly.

a. On the equator : Alnus ylufinosa, Ul-
mits camjyestris, Collomia linearis, Cam-
2>amda Specidum.

b. All over the gi'ains : Basella alba (PI.
40. fig. 19).

tt Scattered irregularly.

a. Outer coat shghtly granular : many
Nyctaginepe, Convolvulaceas, Chenopo-
diacese, Alsineae, Alisma Plantayo ( PI.
40. fig. 10), Plantayo lanccolata, liibes
yjiyrum, Cactus Opuntia, Sfc.

b. Outer coat granular and spinv : Cvcur-
bita Pepo (with lids, PI. 40'. fig. 22),
Malvaceaj (fig. 26).

c. Outer coat with cell-like reticulations :
Polyyonum amiiliibium, pcrsicaria, Co-
bcea scandens.

Compound porous forms occur in some
of the Onagraceai, and in Drimys Winteri,
where four grains are conjoined telralie-
drally. In the MimosejB groups of eight
or sixteen (PI. 40. fig, 25) occur in A-arious
forms. In Zesc/ienaultiafor7nosa the grains
are quaternate, lying in one plane.

D. Outer coat with both furrows and pores.

* Grains rounded or depressed, with
three depressions, each with a pore :
most l)ipsacea3 and Geraniacese
(sometimes only two occur, PI. 40.
fig. 22).

** Three furrows and three pores.

a.. Outer coat granular : a very common
form among Dicotyledons.

b. Outer coat spiny : most Compositoe.

0. Outer coat with cell-like reticulations ;
rare : Syrinya vulyaris, Liyustrum lul-
gare, Greioia occidcntalis, and other
species.

POLLEN.

[ 619 ]

POLYCYSTINA.

*** Outer coat with more than three
furrows, each with a pore. Some-
times abnormally, instead of three,
but normally in most of the Boragi-
naceie and Polygalacea;.

**** Six to nine furrows, three con-
taining a pore : Lythraceaj, Mela-
stomacea3, Combretacese.

***** Three or four furrows, with six
or eight papilliB : Neurada promm-
hens, ^-c.

****** Three furrows and three papillfe
not in the furrows : Carolinea cam-
pesfris, Sfc.

Starch-corpuscles exist in the fovilla of
some pollen-grains in the form of very small
grains which are stained blue by iodiue.

Related compound forms occur in the'
Ericacefe and Epacridacete, where the grains
are tetrahedrally an-auged (PL 40. fig. 17).
Other aberrant forms occm- in which the
single grains are cubic or dodecahedral ;
and in the Cichoracese polyhedral forms of
complicated character are common (figs. 16,
27, 28).

Mature pollen-grains should be observed
drv (as opaque and transparent objects), and
iu water or glycerine ; in some cases, in oil ;
treatment with acids is also useful iu making
out structure. In observing the develop-
ment of pollen, it is necessary to wet the
object with a solution of sugar or gum ;
otherwise the appearances are altogether
changed through endosmotic action.

BiBL. Nfigeli, Enticick. des Pollens, 1842,
and on Cell-formation, liai/ Society, 1846,
1847 ; Hofmeister, Bot. Zeit. vi. 1848 ;
Gieswald,inni«?«, XXV. 81; Schacht (Coni-
ferse), Beitrag z. Bot. 1854 ; Saccardo,
Kuovo Giorn. Bot. 1872 ; Ilassall, An. N. H.
1841 & 1842 (pis.) ; Smith, M. M. Jn. xvii.
9 (figs.); Edgeworth, Pollm, 1877 (446
figs.), & M. M. Jn. xviii. 190 ; Qu. M. Jn.
1880, XX. 19; V^^&rmmg, Uansteins Bot. Abh.
1873.

POLY AC'TIS.— Separated from Botrytis
on account of the dark, quasi-carbonized
flocci.

POLYAR'THRA, Ehr.— A genus of
Rotatoria, of the family Iljdatinsea.

Char. Eye single, cervical ; foot absent ;
body with six cirrhi or fins on each side.
Jaws each with a single tooth.
P. platyptera (PI. 44. fig. 19). Body
ovato-subquadrate, fins ensiform serrate ;
freshwater ; length 1-190".

P. trifjla. Fins setaceous ; freshwater
length 1-1 no".

BiBL. Ehrenberg, Infus. p. 440.
POLYCLI'NUjNI, Sav.— a genus of Tu-
nicate Mollusca, of the family Botkyllid^
(p. 115).

P. aurantmm. Consists of little rounded
orange masses, fixed to rocks by a short
and thick peduncle.

BiBL. Forbes and Hanley, Br. Moll. i.
14.

POLYCOC'CUM, Sant.— A genus of
Micro-lichens, parasitic on the prothallus of
Stcreocaulon eondensatum.

Char. Spores eight, small, bilocular,
brown.

BiBL. Lindsav, Qu. Mic. Jn. 1869, 343.
POLYCOC'CUS, Kiitz.— Probably be-
longs to Microcystis (Rab., Alg. ii. 55).

POLYCO'PE, Sars.— A bivalved Ento-
mo.stracon of the Cladocopa group. Upper
and lower antennae both natatory and seti-
ferousj two pairs of posterior limbs, the
first natatorj', the second branchial; no
eyes ; no heart ; intestine imperforate.
Valves circular, tliin, smooth, or orna-
mented. Marine ; recent and fossil.
BiBL. Brady, Linn. Tr. xxvi. 470.
POLYC YS'TINA, Ehr.— A family of
Radiolarian Rhizopoda.

The animal bodies are contained in shells
of various forms (PI. 39. figs. 23-31).
These are rounded, conical, oval, radiate,
star-shaped &c., often furnished with spines
and other processes, and sometimes con-
stricted so as to give them a jointed ap-
pearance. The shells are siliceous, every-
where perforated by coarse, rounded or
angular foramina ; and at one end, some-
times at both, is a larger aperture. The
animal matter is olive-brown or yellowish.
The Polycystina have been foimd on nearly
every ocean-bottom. Ehrenberg found
them at Cuxhaven, and in the Antarctic
seas ; Bailey in the depths of the Atlantic ;
Miiller in the Mediterranean, and Hiickel in
the Adriatic; Wallich in the Indian Ocean;
and Wyviile Thomson, Carpenter, and
Gwvn Jeftreys in the deep-sea soundings of
the North Atlantic. The siliceous skeletons
or shells accumulated in thick deposits
during the last geological periods ; and
myriads of these exquisite microscopic forms
may be obtained from many strata in Sicily,
Greece, Oran, Bermuda, Richmond, Vir-
ginia, and Barbadoes. They are rare in the
Chalk.

BiBL. Ehr. Monatsh. Berl. Ak. 1846,

POLYCYSTIS.

[ 020 ]

POLYNEMA.

1850; Microg. 18.54; Miiller, Thalass. Sf
Polycyst., Abh. Ak. Wiss. Berlin, 1858 ;
Haeckel, Rudiolarien, 1862 ; Furlong-, Qu.
Mic. Jii. i. 18G1-64; Claparede et Lach-
niann, Inf. 434; Wallich, Tr. Mic. Soc.
n, s. xiii. 75 ; Thomson, Deep Sea, 98.

POLYCYS'TIS, Kiitz.-See Clathro-
CYSTis. Is a Microcystis.

POLYCYS'TIS, Leveille (Urocystis,
Hallier). — A genus of Ustilagiuei (Hypo-
devmous Fungi), including several of the
old species of Uredo ; P. colckici, P. parul-
lela, and P. violce are British. See Ustila-

GINEI.

POLYE'DPtlUM, Niig.— A genus of
Unicellular Algae.

Char. Cells single, 3-4-8-angular, the
angles more or less produced. Several
species, in freshwater pools. P. longi-
spinum (PI. o. fig. 13).

BiBL. Rabenh. Aly. iii. 61 ; Archer, Qu.
Mic. Jn. 1871, 96.

POLYEM'BRYONY.— This term is ap-
plied to a phenomenon occurring sometimes
regularly, sometimes abnormally in the de-
velopment of the ovules of Flowering Plants.
In the Angiospermous plants it is usual to
find several germinal masses in the unferti-
lized embryo-sac (see Ovule); but ordinarily
only one of these becomes impregnated and
developed. Occasionally, however, more
than one commences the course of develop-
ment into the embryo, as in the Orchidacepe,
and more especially in the genus Citrus: in
most cases all but one become subsequently
obliterated; but in the orange this is not
the case, and ripe seeds are met with con-
taining more than one embryo. We have
met with them in other cases.

Another kind of polyembryony occurs in
the Santalaceaj. Viscitm has two or three
embryo-sacs ; these may all have their ger-
minal masses fertilized, and the develop-
ment of the embryos may go on to a certain
point, until one takes the lead and the
others disappear.

In the Gymnospermia (Couiferfe and Cy-
cadacese), as described in the article Ovule,
there may be one or more (Taxns) primary
embryo-sacs, in which are produced several
corpnsada, with secondary embryo-sacs;
furtlier, the germinal masses of these, after
fertilization, produce suspeusors, which
branch at tlieir lower ends, and each pro-
duces four riidimentary embryos, all but
one of them vanishing during tlie ripening
of the seeds. Our space only admits of a
brief notice of these interesting phenomena,

on which much interesting iufomiation wiU
be found in the works referred to below.

BiBL. Meyen, On Impreynation and Poly-
emhryonij, Taylor's Sc. Mem. iii. 1 ; Brown,
Ann. N. H. xiii. 3G8 ; Mirbel and Spach,
Ann. Sc. Nat. 2. xx. 257 ; Criiger, JBot. Zcit.
ix. 57 ; Gelesnoff", Ann. Sc. Nat. 3. xiv. 189,
and the works of Hofmeister cited under
Ovule.

POLYGAS'TIIICA.— According to Eh-
reriberg's system, the Infusoria were sub-
divided into the Polygastrica and the Rota-
toria. The so-called Polygastrica now cor-
respond to the Infusoria; the Rotatoria
forming a distinct class.

POLYl'DES, Ag.— A genus of Cr^-pto-
nemiaceae (Florideous Algre), containing
one British species, P. rotuiidus (PI. 4.
fig. 3), having a branched frond 4 to 6"
high, consisting of repeatedly dichotomous,
purplish-brown, solid fibres, about 1-20" in
diameter. The fibres present a central layer
of longitudinally arranged filamentous cells,
and a cortical layer of perpendicular, dicho-
tomous filaments, formed of elliptical cells
internally, terminating at the surface in
minute moniliform rows. The fructification
consists of: — 1. favellce heAvmg spores, con-
tained in superficial wart-like bodies, com-
posed of colourless articulate filaments ; 2.
tetrahedrally divided tefrasjwres, embedded
in the peripheral filaments of the cortical
layer of the frond. Antheridia have not
yet been observed.

BiBL. Harvey, Mar. Alq. 146 ; Phyc.
Brit. pi. 95 ; Greville, Ah/. ^Brit. pi. 11.

POLYKRIKOS, But.-chli.— A genus of
Holotrichous Infusoria. P. Schicartzii,
marine. (Kent, Inf. 508.)

POLYMORPIli'NA, D'Orb.— A genus
of Hyaline Foraminifera. luequilateral,
oblong or elongate, globose or compressed
(PI. 23, fig. 40, P. coiiimunis; fig. 42, P.
ohlonya ; fig. 43, P. co7npressa) ; chambers
often numerous, alternate in two rows,
sligluly embracing, but always more so on
one side than the other ; orifice round, at
the summit of the last chambers, radiate.
Sometimes the later chambers have branch-
ing, tubular apertm-es (P. Orliynii, PL 23.
fig. 41).

Many species in all seas ; fossil from the
Trias upwards.

JjiBL. Williamson, Pec. For. 70 ; Car-
penter, For. 166 ; Brady, Parker, and Jones,
Linn. Tr. xxvii. 107.

POLYNE'MA. — A genus of Jlymenop-
terous insects. The^perfect insect is aquatic

rOLYG'XA.

[ 621 ]

POLYPI.

in its habits,, swimming by means of its
wings. It lays its eggs inside those of
Dragonflies.

liiBL. Lubbock, im«. T;*. 1863; Metam,
Insect. 37.

POLYCE'CA, Kt.— A genus of Choano-
flagellate Infusoria. Like Salpim/wca, but
the carapaces united into a branched 7.oi\vj.
P. dichotoma, marine. (Kent, Inf. 3G0.)

POLYOM'MATUS, Latr.— A' genus of
Lepidopterous Insects, of the family Lycae-
nidfe.

Char. AntenniB terminated by a con-
tracted knob ; tarsal claws minute ; wings
not tailed.

The (thirteen) species are small butter-
flies, the upper surface of the wings of a
beautiful blue colour, the under side grey
or brownish, and with numerous eye-like
spots.

The scales upon the under surface of the
wings of P. arr/iolus and P. argus have
been proposed as test-objects. They are of
two kinds — one resemblmg in structure the
ordinary scales of insects, the other of a
battledore form (PI. 34. figs. 20 & 21). See
Scales of Insects and Test-objects.

The species are figured in Westwood's
British Butterjlies.

POLY^PHE'MUS, Miill. — A genus of
Cladocerous Entomostraca, family Poly-
phemidiB.

Char. Head distinct from the body ; ab-
domen long, slender, and projecting exter-
nally from the shell.

P. pedicuhis (PL 19. fig. 29). The only
species. Freshwater.

BiBL. Baird, Brit. Entomosfr. Ill ; An,
N. H. X^Ti, xix. 119 ; Clans, Pohjph.lSn.
POLYPHRAG'MA, Reuss. — A large
stichostegian Arenaceous LituoJa, with nu-
merous short chambers and cribrate septa.
Fossil ; Cretaceous. Saxony and Bohemia.
BiBL. Von Reuss, Geinitz^ s Elbihalyehirye,
I. iv. 139.

POLYPI. — A group of Zoophytes, com-
prising the Actiuaria and Ilydroida. Body
rounded or cylindrical, with a distinct
mouth, surrounded by retractile non-ciliated
tentacles or radiating lobes: individuals
usually aggregate ; gemmiparous and ovi-
parous.

The polvpes are usually enveloped in an
external (PI. 41. figs. 45, 12, & 14), or
supported by an internal axial skeleton
(PL 41. tig. 6), called the polypidom. This
is either horny, leathery, or calcareous.
Most polypes are united into smaller or

larger groups by the polypidom, which
often possesses an elegant plant-like foriu
(PL 41. fig. 15). The tubular or cup-
shaped processes or cavities in which the
body of the individual polypes is contained,
form the polype-cells or capsules ; they are
sometimes furnished with a kind of lid.

The structure of the calcareous polypi-
doms has not been satisfactorily deter-
mined. They are usually traversed by vas-
cular caiuxls, and appear in some cases at
least to consist of aggregated and fused
spicula.

The polypes are rarely free, or capable of
fixing themselves by a disk at the base of
the body, as in Hi/dru, being usually fixed
at the bottom of the polype-cells, the poly-
pidoms being attached by a rooting base to
some foreign body. Imbedded in the outer
parts of the soft substance of the body,
especially the tentacles, are stinging organs
(PL 41. fig. 22), resembling in general those
of the Acalephfie.

In many, distinct muscles are present ;
but the fibres are not transversely striated,
although frequently exhibiting wrinkles. In
some polypes, the substance of the body
consists entirely of sarcodic substance. In
many, both the integument and the sub-
stance of the body contain calcareous spi-
cula (PL 41. figs. 7, 27, & 28).

The alimentary apparatus consists of a
mouth and a simple gastric sac, the fiod
being admitted and the undigested portion
rejected from the single apertm-e, except in
one genus, where the anus is separate. The
oral orifice is usually surrounded by a ring
of contractile arms and tentacles, which are
hollow internally, and communicate with
the cavity of the abdomen ; sometimes the
tentacles are distributed over the surface of
the body.

The simple gastric cavity is usually sepa-
rated from the cavity of the body ; Avhere-
by a larger or smaller abdominal cavity is
formed, which is usually prolonged futo
the hollow arms, and in many polvpes
living in colonies passes into the canals
traversing tlie interior of the polypidom, so
that the abdominal cavities of the indi-
vidual polypes are all brought into con-
nection by these canals. Sometimes longi-
tudinal partitions run like a mesentery
from the outer to the inner surface of the
abdominal walls, thus dividing the abdo-
minal cavity into chambers. The bottom
of the gastric cavity is provided with one
or more spontaneously closeable openings,

POLYPI.

[ 622 ]

POLYPODIACE.E.

by which it communicates with the abdo-
minal cavity. Tlie gastric cavity is covered
with ciliated epithelium, which is continued
through the gastric apertures into the ab-
dominal cavity, and here not only covers
the outer surface of the stomach and the
septa, but also the inner surface of the ab-
dominal walls, the cavities of the arms, and
the canals of the polypidom.

The walls of the stomach are variously
coloured, white, yellow, or brown, from the
presence of aggregations of pigment-cells
(liver cells), which probably perform the
function of a liver, as there is no glandular
appendage corresponding to a liver pre-
sent.

A peculiar circulation takes place in most
polypes, by the to-and-fro motion of a
nearly transparent liquid containing minute
colourless corpuscles, in the abdominal
cavity. In the colonial polypes, this circu-
lation continues through the canals which
traverse the polypidoms, from one abdo-
minal cavity to the other.

The propagation of the polypes takes
place : by spontaneous division, which is
mostly longitudinal and rare ; the forma-
tion of gemnue or buds, which is very com-
mon, the individuals either separating or
remaining attached ; and by the formation
of ova. Most of the gemmae become deve-
loped into ordinary polype-cells, and so
produce the growth of the compound orga-
nism. But in many polypes, some of them
grow into large cells, of different form from
the common polype-cells, constituting the
ovarian vesicles, or capsules (PI. 41. figs.
14 i and IGi). In these, the gemmae,
which are developed within them, and
Avhich are often called o^a, gradually be-
come bell- or disk-shaped, and assume the
form of Acalephcp. ; and on escaping from
the vesicles, swim about freely, subsequently
either becoming directly developed into
new polypes, or acquiring sexual organs
and producing ova.

In other (simple) polypes, distinct sper-
matic and ovi-sacs occur in the parent
animals; either together in the same ani-
mal, and external {Hyiira), or separately in
different individuals and internal {Actinia,
etc.).

The ovum-embryo of the polypes is
usually more or less elongate-oval, coated
with cilia, and moves about on its long
axis like an infusorium. After a short
time, it fixes itself to some object, the cilia
disappear, and the tentacles of the polype

are protruded ; as these polypes increase by
gemmation, new colonies are formed.

The formation of coral reefs and islands
by the skeletons of polypes is well known.

The new names of the Polype-structures
will be found in the Art. Hydeoida, and
Hincks's 'Zoophytes.'

POLYPODIA'CE-'E. — An order of
Ferns, divided into 13 families by the cha-
racters of the sporanges.

Si/no2)sis of the Families.
* 8ori tvith an indusium {except Alsophila).

Cyathe.^. Sporanges numerous, sori on
a raised receptacle, with a somewhat ob-
lique annulus.

DiCKS0NiE.i3. Sori globose, on the back
or apex of a vein ; indusium subglobose,
free, at length bursting iri'egularly, more
frequently cup-shaped, entire or with 2
lips.

Hymenophylle.^. Sori terminal or
marginal from the apex of a vein ; recep-
tacle elongate, often filiform, and more or
less exserted, clothed with sessile orbicular
subpeltate compressed capsules, with a
transverse ring opening vertically.

Davallieje. SoiT rounded, marginal or
submarginal, covered by a reniform or
rounded scaly indusium open at the apex,
fastened broadly at the base, and open at
the sides.

LiNDSAYE.'E, . Sori in a line at or near
the end of the frond, inner valve of indu-
sium membranous, the outer formed of the
margin of the frond.

Pteride^. Sori marginal, linear or ob-
long ; indusium of the same shape as the
sorus, formed of an altered and reflexed por-
tion of the frond, opening inwardly.

Blechne,^. Sori linear or oblong, dor-
sal, parallel with the midrib and edge of
the segments, not close to the latter ; indu-
sium shaped like the sorus, superior, open-
ing towards the midrib.

AsPLENiE^. Sori attached to the veins,
oblique or subparallel to the midrib, linear
or oblong. Indusium shaped like the sorus,
when single, opening towards the midrib,
sometimes double.

ScoLOPENDRiE.E. Sori as in Aspleniere,
but the indusia arranged in pairs and open
towards each other.

AspiDiEiE. Sori dorsal, subglobose,
rarely elliptical ; indusium superior, sliaped
like the sorus, fixed either by the centre or
a sinus.

rOLVrODlE/E.

[ Gi>3 ]

POLYSTOMELLA.

** Imlnsium absent.

PoLYPODiEJE. Sori on the back of the
lobes, round or rarely oblong, not more
than twice as long as broad.

Grammitideje. Sori on the back of the
lobes, more than twice as long as broad,
usually linear.

AcROSTiCHE-^. Sori spread over the
imder surface or rarely both surfaces of the
frond, not contined to the veins.

POLYrODIE'.E.— A family of Polypo-
diaceous Ferns; contains the single genus
Poll/podium.

POLYPO'DroM, Linn. — A genus of
Ferns with naked sori, of which there are
several indigenous representatives, P. vul-
gare, the Oak-Fern, being one of our com-
monest species. Exceedingly well adapted
for examination of the structiu-e of the sori
and sporanges in this family.

POLYPOK'EL— A faniily of Hymeno-
mycetous Fungi, characterized by bearing
basidiospores lining tubes, pores, or pits,
on the underside of a stalked or sessile
jn'leus, or fleshy cap or disk. The basidio-
spores are seen by horizontal sections from
the undersurface of the pileus. (See Ba-
sidiospores and Hyjiexomycetes.)

Bebl. Berk. Fruct. of Fungi, Ann. N. H.
i. 81 ; Lgveille, Ann. Sc. N. 2. viii. 324.

POLYSAC'CUM, D. Cd.— A genus of
Trichogastres (Gasteromycetous Fungi),
having a common peridium filled with
peridiola ; the spores mixed with threads.
One species only occurs, and very rarely in
this country. Abroad they grow on exposed
sand. One of the species has been used in
dveing. P. crassipes, p. 349, fig. 200.
'Bibl. Fr. Sgsi. Myc. iii. 54; Berk.
Outl. 304; Sow. t. 425; Cooke, Handb.
375.

POLYSEL'MIS, Duj.— A doubtful genus
of Infusoria, of the family Euglenia.

Char, Oblong or variable in form, with
several anterior flagelliform filaments, and a
single red eye-spot.

Probably the zoospore of a Confervoid
Alga.

P. viridis (PI. 31. fig. 68) resembles a
Euglena of an oblong form with the ends
rounded ; one of the filaments is longer than
the three or four others which surround its
base. Freshwater ; length 1-650''.
Bibl. Dujardin, Infus. 370,
POLYSIPHO'NIA, Grev.—Anextensive
genus of Rhodomelese (Florideous Algas) or
Red sea-weeds, with cylindrical, more or less

articulated fronds, the joints consisting of a
circle of longitudinally arranged cells sur-
rounding a central cell, like the wood-
bundles of a young Dicotyledonous stem
surrounding the pith, so that the ti'ansverse
section presents the appearance of a rosette.
The number of peripheral cells varies among
the 300 different species of this genus, from
four to twenty-five ; the British forms
mostly have four and six. In some of the
species a kind of rind is formed subsequently,
by a growth from the base of the joints
analogous to that which occurs in Batra-
CHOSPERMUM and Callithamnion. The
fructification consists of: — 1. ceramidia, urn-
shaped or ovate, attached to the sides of
branches, containing nume-
rous pear-shaped spores at
the base ; 2. tetraspores on
distinct plants, formed in the
swollen central cell of dis-
torted branches (fig. 598) ;
these are gonidia and develop
a thallus ; and 3. antheridia,
elongated whitish sacs, col-
lected in great numbers at
the summi ts of the branches,
accompanied by a dichoto-
mous hair, and sometimes
prolonged into a hair-like
process at the summit. Nageli
describes the spermatozoids
as consisting of a spiral fila-
ment, Thmet states that
they are merely hyaline glo-
bules, about 1-5000" in dia-
meter, without active motion.
The British species are placed
in two subgenera — Oligosi-
phonia, where there are but
four or rarely five peripheral
cells, and Polys{pJionia,\\h.evQ
there are six or more.
Twenty-six species are de-
scribed, many of which are common.
fastigiata, PI. 4. fiff. 20.)

Bibl. Harvey, "Mar. Ahj. 82, pi. 12 A ;
Thuret, Ann. Sc: K 3. xvi. io, pi. 6 ; Nageli,
Zeitsch. tviss. Bot. 1846, 207, pis. 6 .fc 7 ;
Henfrev-Masters, Bot. 433.

POL YS'TICHUM = Aspidimn pt.
POLYSTOMEL'LA, Lamk.— A genus of
Hyaline Foramiuifera. Shell free, regular,
equilateral, biconvex, sometimes compressed,
otten dorsally keeled; spire embracing;
chambers with a single cavity, straight or
arched, meeting at the umbilicus and fur-
nished with transverse pits between the

Polysiphonia.
nigresoens.

Distorted ramuH
containing im-
biddi-d tetra-
spores.

Magn. 50 diams.

{P-

POLYTIIALAMIA.

[ 624 ]

POLYTRICIIUM.

sutures or over them. Orifices numerous,
arranged along the margin of, or forming a
triangle at, the upper part of the last cham-
ber. Polystomella passes into Naniojilna,
through P. striato-punctata (PL 24. f. 19),
common in cold seas.

P. crispa (PI. 24. fig. 20) is common in
temperate seas. P. eraticulata is of tropical
growth. P. macdla (^Faujasina) is unsym-
metrical and starved. Many fossil forms.

BiBL. D'Orbigny, For. Vien. 121 ; Wil-
liamson, Fornm. 39 ; Morris, Br. Fossils, 40;
Parker & Jones, Ann. X. H. 3. v. 103 ;
Carpenter, For. 276.

POLYTHALA'MIA. See Fokamini-

FERA.

POLYT'OMA, Ehr.— A genus of Fla-
gellate Infusoria, family Mouadina (Hydro-
morina).

P. iwella (PL 31. fig. 69, undergoing di-
vision), the only species, is oblong or oval,
obtuse at the ends, colourless, furnished with
two flagelliform filaments ; it has no cara-
pace. Fresh or decomposing water ; length
1-2200 to 1-960" ; size of body when the
division is nearly complete, 1-400".

As it increases in size it assumes a wrinkled
or mulberry appearance, and this indicates
the approaching division into many sections,
whence the name.

PiBL. Ehr. Inf. 24 ; Schneider, Ann. N.
II. 18o4, xiv. 321 ; Pritchard, Inf. 136 &
504 ; Kent, Inf. 301.

POLYTRE'MA, Blainville.— A protean
parasitic Foraminifer of the Rotaline family ;
scale-like, globular, or arborescent, with
cancellated structure. P. miniucemn is
widely distributed in the Mediterranean and
other warm seas.

BiBL. Carpenter, For. 235; Schultze,
TViepn. Arch. 1863, 81 ; Ann. N. H. 3. xii.
409 ;' Carter, ihid. 4. xvii. 185 ; 5. v. 440.

POLYTRICIIA'CEyE. — A tribe of
MnioidciB (operculate Mosses of usually
Acrocarpous habit).

Getiera.

Cathnrwen. Calyptra narrowly hood-
shaped, subscabrous at the apex, rather hairy
within. Peristome simple, composed of
thiity-two teeth, arising from a narrow,
cellular basilar membrane, ligulate, mem-
branous, white, with many percurrent,
reddish, inarticulate iilaments, somewhat
incurved, scarcely hygroscopic, firm. Colu-
mella dilated at the apex into a drum-like
epiphragm. Capsule equal. InHorescence
monoecious or dioecious.

Fig. 599.

Pohjtrichinn. Calyptra dimidiate, but
appearing campauulate on account of a
quantity of very close hairs descending from
it as a long villous coat ; otherwise resem-
bling the preceding genus.

POLYT'RICHUM, Dill.— A genus of
Poly trichaceous Mosses, variously defined by
diflerent authors. In the British'Flora, it in-
cludes the forms separated in this work under
Cathabinea, which in the 'Bryologia Bri-
tannica ' are divided between Atrichum and
OUyotrichum. The species of Pohjtriclnoa
comprised in our definition are distributed in
the same work under Poyonatum. (those with
a ronnd capsule and thirty-two teeth) and
Pohjtrichum proper (those with a square or
prLsmatic apophysate capsule (tig. 600 ), and
usually twice as many
teeth ). P. commune is
one of o ur finest Mosses,
common on heaths,
moors, and mountain
tracks, varying some-
what under the differ-
ent physical conditions.
The stems are from
6" to 1' long, and the
fruit-stalks 2 or 3".
The stems are almost
of woody texture, the
leaves large and firm.
The calyptra is den.sely
covered with hairs.
Wilson remarks that
the true structure of the
sporauge and columella
of Mosses may be most
easily learned from
the study of this
genus. The columella
is seen (figs. 601, 603),
to be separated from
the spores by an
imier layer of the spo-
rangial membrane. The
diaphragm attached
to the apices of the
teeth of the peristome is
the dilated apex of the columella (fig. 603).

The peristome (fig. 602) is composed of
ligulate obtuse teeth, connected by a m(>m-
brane at the base, continuous with the inner
layer of the wall of the capsule. These
plants are also exceedingly Avell adapted for
the examination of the male inficn-escence
and spermatozcids. They are all dicecious ;
and the male plants (lig. 604) are readily
distinguishable by the cup-shaped infiores-

Polytrichiim commune.

Plants in fruit.
One half natural size.

rOLYTRICIIUM.

[ 625 ]

rOLYZOA.

cence, composed of scale-like leaves and
pavaphyses suvrounding a uuniber of subu-
late sacs constituting tiie aniherklia. The
male tlowersof P. commune ^uiuperinum,Sic.

Fig. 600.

Polytrichum commune.
Capsule with operculum. Section of young capsule
Magnified 10 diameters. showing the plaited spo-

" rangial membrane.

are found everywhere on heaths in spring.
The antheridia'may be readily extracted un-
der a simple lens, and, when placed iu vrater

Polytrichum commune.

Fragment of peristome. Columella with section

Magn. 100 diams. °^ ^^^ apophysis.

Magn. 25 diams.

under the compound microscope, soon (if
ripe) hurst at the summit and discharge the
spermatozoids ; these usually escape still
enclosed in their parent cells, which when
first discharged cohere in a gelatinous mass ;
hut the ciliated spermatozoids (PI. 40. fig.
33) escape and swim actively in the water.

They require at least an eighth object-glass
for examination ; and the cilia are seen most
clearly after drying the object, or treating
it with tincture of iodine.

Fig. 604.

Fig. 605.

subkingdom

Poljiirichum commune.
Male inflorescence. Innovation from male

One half nat. size. inflorescence.

Magn. 5 diams.

BiBL. Wilson, Bryol. Brit. p. 205 et seq. ;
Tburet,. Ann. Sc. Nat. 3. xvi. 26, pi. 14.

POLYZO'A or BRYOZOA.— A class of
Animals, belonging to the
Mollusca.

Char. Polypiform, aggregate ; indi-^-idual
bodies microscopic, contained in horny or
calcareous cells, often connected by tubular
stems, forming a usuallj' branched zoary ;
mouth stUTOinided by long, ciliated, uncon-
tractile tentacles ; mouth and anus separate,
but near each other. Marine and fresh-
water.

They are found everywhere on the sea-
shore, either rooted to, or forming a crust
upon submerged rocks, stones, shells, &c.
The individual is called a polypide ; and
the aggregate or colony constitutes a
coenoicium or polyzoarium ; it is usually
of a whitish or brownish colour, of a
horny or calcareous textvire, and consists
either of cells or cups simply aggregated
(PI. 41. figs. 17, 20), or connected by tubu-
lar stems, and often- arranged in elegant
plant-like forms (PI. 41. fig. 5 a). The
stems are divided into compartments by
perforated septa (PL 41. fig. 5/), through
which thread-like filaments of the sarcode
pass.

2s

POLYZOA.

626 ]

POLYZOA.

Tlie cells are of various forms, mentioned
under the genera, and the j are often furnished
with bristles or spines. At the orifice of
each cell the tentacles and more or less of
the body of the animals are protruded. In
the marine or Infuudibulate order, the struc-
ture of the cell-mouth is used as a charac-
ter,— those in which itis terminal and simple
(PI. 41. fig. 30) forming the Cyclostomata ;
and those in which it is subterminal, curved,
and furnished with a movable lid, the
Cheilostomata (PI. 41. fig. 5 b) ; whilst in
the Ctenostomata there is a comb-like cir-
cular fringe of bristles connected by a mem-
brane surrounding ths cell-orifice, visible
when the body is partly protruded. Most
are fixed ; but CridatcUa is free and loco-
motive, having a discoid base.

Curious appendages are found attached
mostly to the cells of the polyzoaries. The
first are called bird's-head processes or avi-
cuJaria (PI. 41. fig. 5h*, and fig. 20).
They consist of a body (fig. 26 c/), a hinge-
or lower -jaw-like process (fig. 26 e), and a
stalk (/). They are attached by the stalk
to the interior of a round hollow process,
projecting slightly from the surface of the
polyzoary (fig. 26 a). The body is divided
by an oblique ridge (fig. 26 d) on its inner
surface into two chambers. The lower
portion is moved up and down by an
elevator and depressor muscle (fig. 26 c).
During life the motion is constant ; and it
continues long after the death of the animal.
These bodies appear analogous to the pedi-
cellaria of the Echinodermata.

The second kind, called vihracula, consist
of a hollow process (fig. 5 cl, b), from which
a vibrating filament (fig. 5 d) projects.
The interior of the process is filled witli a
contractile substance which moves the
filament.

The body is usually oblong or elongate.
At its anterior end is a ring or disk {lupho-
phore), upon which the tentacles are placed ;
tliis is perfect in the Infundibulata, but
deficient at one part, or horse-shoe shaped
in the Ilippocrepia (PL 41. figs. 3 c & 9).
The tentacles are hollow, closed at the end,
uncontractile, coated externally with cilia
on the sides next each other, and communi-
cate with the cavity of the body through
apertures in the disk. In most of the Ilip-
pocrepia, the tentacles are surrounded at the
base by a transparent cup dike membrane
(cali/x), prolonged somewhat upon each ten-
tacle, and mostly dentate at the margin.

Digestive System. — The mouth is situated

in the middle of the tentacular disk (PI. 41.
fig. 3 c), and is closeable in the Ilippocrepia
by an epiglottis-like hollow valve {ejnstome),
which IS absent in the Infundibulata; at the
base of this valve is an aperture which per-
forates the disk to open into the abdominal
cavity. The mouth terminates in a pharynx
(PI. 41. fig. -l e, /), and oesophag-us (tig. 18,
b, d), often of considerable length, which is
sometimes succeeded by a strongly muscular
gizzard. Next comes the stomach (figs.
5 e, b, 18 f), often very capacious, and
with an appendix (fig. 18 e), and finally the
intestine (fig. 18 y), which terminates out-
side, but close to the disk (fig. oe,c). Thus
the alimentary canal is bent upon itself, the
two orifices being very near each other.

The alimentary canal consists of three
coats — an inner rugose, composed of cells
with brownish contents, and representing a
liver ; a middle, composed of colourless
nucleated cells ; and an outer, thin, cellular
coat, probably containing muscvUar fibres.
The mouth and more or less of the upper
portion of the alimentary canal are ciliated.

The walls of the cavity of the abdomen,
the interior of the disk and of the tentacles
aU communicate, and are filled with a clear
liquid, in which irregular particles float,
and in which a constant rotatory motion
exists, produced partly by muscular action,
and partly by cilia. This liquid corresponds
to a chylaqueous fluid, and performs the
chyliferous, sanguiferous, and respiratory
functions ; for there are no distinct respira-
tory organs, nor blood-vessels.

The muscular system is well developed,
the fibres being transversely striated — the
principal, or retractors, arising from the
bottom of the cells, and being inserted into
tlie sides of the oesophagus, so as to exert
a retracting action upon the body. There
are also parietal muscles, which are in the
form of circular bundles running transversely
round the cell; they project the polypide.

The nervous system consists of an oval
ganglion placed between the oral and anal
apertures, and giving ott' branches to the
tentacles, alimentary canal, &c. ; and there
is stated to be a nervous connexion between
all the cells of a zoarium, called the colonial
system.

Reproduction. — The Polyzoa are propa-
gated by gemmation, and by the agency of
sexual organs.

Two kinds of gemmation occur. In the
first, the gemm£e are developed externally
from the parent cells, and usually near the

rOLYZOA

[ 627 ]

PONTIA.

orifice, but often from the stem ; these
gemina3, on attaining" their full dcnelopmont,
remain attached to the parent, thus forming-
the compound orgauism. In the second,
they are formed internally, as buds upon
the funiculus, which is a process passing
from the testis to the stomach. Afterwards
they become free within the abdominal
cavity, from wliich they escape at an orifice
near the disk, according to Beneden, al-
though this is denied by Allman. The
latter kind, which are often called ova,
have an external hard coat, exliibiting the
appearance of a marginal ring, and are often
of a dark colour; their development is not
dependent upon impregnation, and they
seem to correspond to the winter ova of the
Entomostraca &c. : Allman proposes the
name statoblasts for them. The sexual
organs, which usually exist together in the
same individual cell, consist of a roundish
ovary, attached by a short peduncle near
the orifice of the cells ; whilst the testis is
a rounded irregular mass attached to the
funiculus. The ova, which are first set free
in the abdominal cavity, are ciliated and
swim freel}'.

Four modes of reproduction in the Poly-
zoa have been described, three of them
taking place in an asexual way : — 1. The
growth of the whole colony by buds which
are external ; 2. The reproduction by eggs
formed by internal buds of the endocyst ;
3. The production of new polypides and
eggs in empty cells (zocecia), by brown
bodies which are produced out of the
former polypide of the cell by retrogressive
metamorphosis ; 4. Sexual reproduction by
eggs and spermatozoa.

The Polyzoa are divided into two orders:

Order I. Hippocrepia {Phylactolcemata),

Tentacular disk horse-shoe shaped or bi-
lateral ; mouth with an epistome j mostly
freshwater.

Order II. Infuxdibulata {Gymnolcemata).

Disk circular, or nearly so ; epistome ab-
sent ; mostly marine. 3 suborders :

Cyclostomata, Cells with a simple round
orifice.

Clieilostomata. Orifices of cells fitted
with a thin, membranous or calcareous
plate ; with a curved mouth, furnished with
a moveable lip.

Cienostomata. Orifices surrounded by a
circle of setse.

BiBL. Johnston, Br. Zooph. 253; Busk,
Ma7\ Polyzoa, Brit. Mus. ; Fossil, Pal. Soc.
18.39; Farre, Phil. Tr. 1837; Dumnrtier
and Beneden, Mem. Ac. Brux. IB-jO ; Han-
cock, Ann. N. If. 1850, v. ; AUman, Freshw.
Poli/zoa, Ray Soc. ; Gosse, Mar. Zool. ii. 1 ;
Muiler, Wiey. Archiv, 18()0, 311; Huxley,
Inrertebr. ; Smitt, Qn. Mic. Jn. 1871, 155 ;
Muiler, Reich. 8f D, Reymond''s Archil^,
18160; Claparede, Sieb. ^- Kail Zeit 1871,
137; Norman, Qu. Mic. Jn. 1868, 212;
Hyatt, Pr. Essex Institute, U. S. A. 1868 ;
Nitsche, Sieb. S,- Kdll. Zeit. 1870; Barrois,
Embryol. 1877 ; Hincks, Polyzoa, 1880.

POM'PPIOLYX, Gosse.— A genus of
Rotatoria, family Brachionfea, P. compla-
pluiiiita ; freshwater. (Gosse, Ann. N, H,
185], viii. 203.)

POMPHOLYX'OPHRYS, Ai-cher, Hy-
alolampe, Greef. — A genus of freshwater
Rhizopoda.

Clutr. Rhizopod composed of two distinct
sarcode regions, the inner a dense coloured
globular sarcode mass, the other colourless,
and bearing a number of separate hyaline
globular structures ; these are disposed in a
layer around the inner globe, which latter
gives ott' slender non-coalescing pseudopodia.

BiBL. Archer, Qu. Mic. Jn. 1870, p. 105.

PONTEL'LA, Lubb.— A genus of Cope-
podous Entomostraca. P. Wollastoni, Wey-
mouth. (Ann. N. H. 2. xx. 406 ; Brady,
Cop. i. 73.)

PONTIA, Fabr.— A genus of Lepidopte-
rous Insects, of the family Papilionidse.

This genus contains some of the com-
monest butterflies, as P. brassicce, the large
cabbage-butterfly ; P. rapce, the small calj-

bage-butterfly ; and P.

napi.

the

green-

veiued white butterfly.

The form and structure of cei'tain scales
existing upon the vmder side of the wings
of the males are curious ; and the markings
were formerly found so difficult to render
distinct, that the scales were used as test-
objects.

In the male P. brassic<s the upper surface
of the anterior wings is free from spots,
whilst in the female there are two black
spots in that situation. The peculiar scales
are represented in PI. 34. fig. 24 ; fig. 26
exhibits a portion of. the wing with the
ordinary scales.

In P. rapce and P. napi the anterior wings
of the males have a single spot upon the
upper surface, whilst there are two upon
each wing in the females. Tlie peculiar
scales bear considerable resemblance in the

2s2

PONTOCYPRIS.

[ 628 ]

PORPHYRIDIUM.

two species (PI. 34, fig. 23 a, scale of F.
rupee ; fig. 23 6, portion of wing, showing
tlie points of attachment of the two kinds
of scales).

The scales may he separated by gently
pressing the nnder surface of the wings
against a slide.

See Scales of Insects and Test-objects.

BiBL. Westwood, Brit. Butterflies.

PONTOCY'PRIS, Sars.— An Ostracode,
near Argillcccia among the Cypriclce, with
fragile pod-like yalves, higher in front than
behind ; no branchial appendage on the
second pair of jaws ; upper antennae long
and setiferous. 3 British species, rather
common.

BiBL. Brady, Linn. Tr. sxvi. 384.

POPPY.— The seeds of Poppies {Pa-
paver, L., Nat. Order Papaveraceoe) are ele-
gant opaque objects under a low power, the
testa being pitted so as to produce a reticu-
lated surface (PI. 39. fig. 14).

PORCELLID'IUM, Glaus.— A genus of
Copepoda. 4 species, among Laminarics,
&c. (Brady, Copep., Ray Soc.)

POKIF'ERA. See Spongida.

POROCYC'LIA, Ehr.— A genus of Dia-
tomaceae closely allied to Liparogyba.

BiBL. Pritchard, Infus. 823,

PORODIS'OUS, Grev.— A genus of Dia-
tomacefe, fam. Melosirse. (Rabenht. Ah/, i.
85 ; Greville, Mic. Tr. 1863, 63 ; 1865, 46.)

PORO'NIA, Fr.— A genus of Sphferiacei
(Ascomycetous Fungi), consisting of a corky
stroma, which is flat or hollowed out at the
top, and studded with the ostiola of the
perithecia. Tlie only British species is not
uncommon on horse-dung.

BiBL. Fr. Si/st. Myc. ii. 330 ; Berk. Outl.
385; Cooke, Handb. 791; Tul. Carp. ii.
27, t. iii.

POROSPH^'RA, Steinm.— Small glo-
bular fossils, common in the chalk, known
as OrhitoHn(T, formerly referred to Sponges
and Foraminifera, now found by Carter and
Steinmann to have Hydractinian structure ;
calcareous, with reticular tissue and radiate
tubes. (Steinmann, PaJceontoqraphica, 1878,
XXV. 120.)

POROUS STRUCTURES of Plants.
— What are ordinarily called porous tissues
in vegetable anatomy are described in ac-
cordance with their real nature under the
head of Pitted structures. . True pores
do, however, occur in the walls of vegetable
cells, from secondary or ultimate changes in
their character. They are seen in the cells
of the leaves of Leucohryum and Spluiynum

(see Sphagnace;e). Other regular orifices
are produced in the walls of the cells of
many of the zoospore-producing Confervoe,
as Conferva, Cladoplwra, Enteromorpha, &c.
(see PI. 9). The wall of the sporangial cell
of Achh/a presents analogous openings ; and
according to Cohn, pores are produced in
the spore-cells of SpHiEROPLEA to admit
the spermatozoids. The pits and the inter-
stices between reticulated fibrous secondary
deposits are often changed into true holes
in old cells, but this is the result of decay
of the primary membrane ; it takes place
very early however, at the contiguous ends
of SpiRAi.-fibrous and Pitted cells coa-
lescing to form ducts, changing the septum
formed by the adjoining ends into a kind of
grating, or irregularly torn diaphragm.

PORPETA, Bail.— A genus of Diato-
macese, closely allied to Biddulphia. Gulf-
stream.

BiBL, Pritchard, 7w/. 350 ; Rabenht. ^/^.
i. 315.

POR'PHYRA, Ag.— A genus of Por-
phyraceae (Florideous Alg.Te), with an ex-
panded, membranous, shortly-stalked frond,
composed of a single layer of cells appi-oxi-
mated in fours, the contents purple or red.
Fructification consisting of: — 1. scattered
sori of oval spores ; 2. octospores immersed
in the frond ; and 3. antheridia, on the
same or distinct plants. P. laciniata and
vulgaris are common on our coasts.

BiBL. Harvey, Mar. Aly. 261, pi. 25 A ;
Thuret, Ann. Sc. Nat. 4. iii. 5 ; Janczewski,
Mem. Soc. Cherhourq ., xvii. 345.

PORPIIYRA'CE.E.— A tribe of Flori-
deous_ AlgfB (according to Thuret), of low
organization, forming Ulvoid membranous
fronds or strata of Confervoid filaments, of
a purple or red colour. They are ])laced
among the Ulvaceae by most authors, but
ditter in the absence of the zoospores and
the presence of tetraspores (octospores) and
antheridia. They are marine, — Porphyra
growing on rocks and stones, Banyin "the
same, or parasitic upon Zostera, Algae, &c.

British Genera.

Po}phyra. Frond plane, membranous,
very thin, of a purple colour, with oval
spores in sori, and tetraspores (square)
scattered all over the frond.

Banyia. Frnnd filiform, tubular, com-
posed of numerous radiating cells in trans-
verse rows, enclosed within a continuous
hyaline sheaJi.
■PORHPY RIDTUM = Palmella cruenta.

PORRIGO.

[ 629 ]

rOTTIOIDEA.

rORRI'CxO. See Favus.

POTAMUCY'PKIS, Brady.— One of the
Cypridcc ; valves reniforiu, thick, right
larger than left ; upper antennte with very-
short set;« ; post-abdomiual rami rudimeii-
taiy. 1 British species.

BiBL. Brady, Kat. Hist. Tr. North. 8,-
Durham, iii. 365.

POTASH, AND ITS SALTS.

Caustic Potash. — The strength of the
solution may be that of the Liq. Potasste
of the Pharmacopoeia. But we prefer a
stronger solution made with 1 drachm of
the potassa fnsa or stick-potash of the
shops, and 1 tluid oz. of water. The solu-
tion should be allowed to settle, and the
clear portion poured off into one of the
test-bottles (Intr. p. xxvii).

Some remarks are made upon the action
of potash in the Inte., and others under
the heads of the tissues, kc. On treating
organic substances with this reagent, tlie
cvstic-oxide-like crystals of the carbonate
(PI. 10. fig. 2Q) will frequently be formed._

Chromates of Potash. — The bichromate is
used in the preparation of the chromate of
lead for injection. Its crystals polarize
well. The neutral chromate is also some-
times used for preparing injections. See
Peepaeation.

Nitrate of potash, nitre, or saltpetre. —
This salt is dimorphous : it usually crystal-
lizes in six-sided prisms with dihedral sum-
mits, or in other forms belonging to the
right-rhombic prismatic system. But some-
times it assumes the form of obtuse rliom-
bohedra, resembling those of nitrate of soda,
and referable to the rhombohedric system.

The crystals exhibit very beautifully the
phenomena of Analytic Ceystals.

POTATO-FUNGUS. See Boteytis.

POT'TIA, Ehr.— A genus of Pottiaceous
Mosses, including some of the Gymnostoma
and ire/ssi'tg of Hedwig and others. Wilson
separates as Anacalyptce the species with a
peristome (fig. GOO).

Fig. 606.

POTTIA'CE.^E.-

Mosses.

-A tribe of Po-tioi

?3

^"^mrnmm

Pottia caespitosa.
Fragment of peristome.
Magnified 50 diametera.

Synopsis of Genera,

Pottia. Calyptra dimidiate. Peristome
simple or wanting ; if present, composed of
lanceolate articulate teeth, simple or with a
longitudinal line, rugulose and somewhat
fleshy.

Trichosto7mitn. Calyptra dimidiate. Peri-
stome simple, sixteen teeth, each split to the
base into two cilia, or irregularly and there-
fore into more than two, erect, stifl^ and
not twisted.

Barhula. Calyptra dimidiate-hood-
shaped. Peristome simple, ciliiform ; cilia
tliirty-two, solitary or approximated in
pairs" on a more or less exserted basilar
membrane, spUt into two cilioles behind,
very long, articulate-rugulose, twisted to
the left, rarely to the right, in one or several
spires, hygroscopic. Cells of the operculum
and calyptra twisted in the same way.

Ceratodon. Calyptra dimidiate. Peri-
stome simple ; teeth sixteen, connate at the
base into a cellular membrane, split into
two long, nodosely articuUi.ted dark-coloured
arms, paler on each side, densely trabeculated
at the lower part. Capsule thick-skinned,
shining, nodding, with a somewhat nodose
collum ; annulate.

Weissia. Calyptra dimidiate. Peristome
simple or wanting ; if present, composed of
sixteen lanceolate or subulate, entire or
cribrose, equidistant teeth.

POTTIOI'DEyE.— A family of Acrocar-
pous operculate Mosses, but sometimes
Pleurocarpous by innovating branches.
Leaves of varied form, with a terete nerve ;
cells parenchymatous, hexagonal or squa-
rish six-sided, looser at the base, sometimes
very lax, more or less pellucid, often ex-
ceedingly transparent, large, fragile, rigid,
foraminate, bearing on the upper side soli-
tary papiUse or confluent papillte (hence
often truncate and tuberculate at the apex),
placed in the middle of the cell ; cells
mostly fuU of chlorophyll, often very small
and thickened. Capsule erect, rarely in-
clined, oval, elliptic or pear-shaped oblong,
smooth or striate, the operculum mostly-
conical or beaked.

This family is divided into three tribes :
Calympeeace^. Basilar cells of the
leaves rigid, hyaline, often very brittle,
more or less ample, empty, distinctly fora-
minated.

PoTTiACEiE. Basilar cells of the leaves

PRASIOLA.

[ 630 ]

PREPARATION.

suft, pellucid, longer, mostly empty, rarely
contaiuing- a persistent primordial utricle.

Orthotrichace^. Basilar cells of the
leaves with only the reiy lowest soft, the
upper mostly thickened, rarely pellucid and
normal.

PRASI'OLA, Meneg-hini.— A genus of
UlvaceiB (Confervoid Algre), separated from
Monostroma by the arrangement of the
quadri geminate cells of the frond in lines,
with wide intercellular walls ; from TJlva
by the existence of only a single layer of
cells, and from both by the absence(?) of
a reproduction by zoospores ; from Schizo-
yonium by the frond consisting of expanded
plates. The species are included imder
Ulva (the terrestrial forms) in the Br. Flora
and Harvey's AJgte, ed. 1. They have been
carefully examined by Jessen, who finds
the fronds proliferous at the margins ; the
" spores " he describes as consisting of mo-
tionless cells formed of the entire contents
of the cells of the frond, set free by the
solution of the parent cell. The reproduc-
tion of this group seems to us to require
further iuvestigation. Jessen includes here
P. calophylln (PI. 3. fig. 10), crispa,fur-
furacea, and a form which he names P.
stipifcita, differing from the last chiefly
in the narrowly wedge-shaped, stipitale
character of the frond : probably the last
three constitute only varieties of one species.

BiBL. Jessen, Frasivlte Monoy. 1848 ;
Harvey, Br. Aly. 171 ; Hassall, Aly. 297,
pis. 77, 78 ; Kiitz. Sj). Aly. 472 ; Rabenht.
Ah/, iii. 308.

PREPARATION of microscopic objects
for examination and preservation. — Some
remarks on the former point will be found
in the Introdxjction, p. xxxii ; and imder
many of the general and special articles,
such as Diatomacese, Ovule, &c., directions
are given. A few general remarks may
still however be made in this place.

The parts of bodies or objects are usually
separated by the mounted needles under a
dissecting microscope, or by means of sec-
tions, according to the nature of the views
which it is desired to obtain. With regard
to the former operation, it need be merely
observed that it is generally to be per-
formed under water, in a watch-glass, glass
cell, or other convenient holder.

The preparation of sections is a more
comyjlicated process. Soft parts of animals
are best sliced by means of a Valentin's
knife : but Armor structures, such as horn,
may be cut with a sharp razor. Vegetable

structures in general are sliced with a
razor, which must be kept very sharp, and
rubbed on a strop frequently while in use,
and always before putting away. Fresh
stems, thick leaves, &c., may be simply
held in the fingers ; thin objects, such as
leaves, petals, &c., are best placed in a split
cork or piece of carrot, the halves of which
are kept together by insertion in the neck
of a vial or a test-tube, which at the same
time serves as a handle. Sometimes it is
advantageous to immerse objects, especially
soft or very small ones, in thick mucilage
of gum-arabic, and to allow this to dry
until tough enough to be cut by the razor ;
the slices are freed from gum by immersion
in water. Dry objects, such as wood, dried
leaves, seeds &c., must be softened by soak-
ing in water before slicing. Small firm ob-
jects, such as softer seeds, are mostly sliced
when fixed in a bit of white wax or
stearine, which may be done by placing
them on the surface of the latter, and
stirring them into the substance melted by
the application of a hot wire. Most sec-
tions of vegetable objects are obscured by
air-bubbles engaged in the intercellular pas-
sages, &c. In old wood and similar objects
immersed in liquid, the air is readily driven
out by heat ; in fresh structures, where
heat may coagulate or dissolve matters, the
air may be allowed to dissolve or escape by
itself, which requires time, or it may be
removed by exhaustion under an air-pump.

Sections of wood, &c., which are to be
mounted in liquids, should be soaked for
some little time in spirit or turpentine, to
remove resins, &c. The Section-cutter is
used for slicing such objects ; but this is
not of much use except when large numbers
of very perfect sections of the same kind
are required for purposes of sale, &c.

It need scarcely be said that sections
require to be made in various directions in
studying objects by these means. Thus
stems should be sliced horizontally, and
perpendicularly both parallel and at right
angles to the medullary rays. A\"hen work-
ing with high powers, it is necessary to be
on our guard against appearances of stria-
tion or fibres which maybe produced by the
fine notches in the cutting instrument.

The structure of laminated shells, Szc,
may often be seen in fragments broken off
by the point of a knife. But sections of
bone, shell, kc, are best made by sawing
off thin pieces with a frame-saw having a
watch-spring blade, grinding them down

PREPAKATION.

C 631 ]

PRESERVATION.

upon a Tvater-of-Ayi* or some other stone,
and polishing them upon a clean leather
hone or strop with putty - powder and
water, finally upon a dry hone ahnie.

Sections of very hard subsitances, as
agate, &c., are so easily made by jewellers,
that a description of the process is scarcely
necessary. They are cut by means of a
rotating' circular iron plate, its margins
being coated with a mixture of oil and
dianiond-dust. They are then ground upon
a plate of metal with emery-powder and
water, and polished upon a Hat surtace of
pitch with putty-powder and water.

In grinding and polishing sections of
hard structures, it is often requisite to
cement them to a slide with Canada bal-
sam, heat being applied until the balsam
has become so hard as to fix the section
firmlv to the slide. As soon as one side
has been polished, the section is removed
from the slide, the balsam being rendered
soft by heat, the polished side cemented to
the glass, and tlie other side polished. The
balsam may afterwards be separated from
the section by maceration in oil of turpen-
tine, benzole, &c.

The more delicate animal tissues require
hardening before section. This is usually
produced by freezing in the section-cutter ;
or by maceration in chromic-acid mixture
(15 grs. of chromic acid to the pint of
water, with ^ a pint of methylated spirit),
bichromate of potash (180 grs. to the pint),
osmic acid, or Miiller's liquid (composed of
220 grs. of bichromate of potash, 90 grs. of
sulphate of soda, and a pint of distilled
water). These liquids require to be poured
oft" and replaced until the tissue is suffi-
ciently hardened.

Great care is required in the interpreta-
tion of the appearances presented by minute
objects or portions of tissue, as to the
intluence of the liquids in which they are
immersed ; even water often totally distorts
their natural appearance, as in the case of
pollen. Sec. And in animal tissues, the
liquid of the allautois, blood-serum, or
iodized serum or albumen (p. 441), are
often useful as con-espouding nearly to the
liquid in which they are naturally im-
mersed, and so producino' but httle change.

Besides these methods of preparation,
there are those which enable the observer
to keep sections or minute plants and animals
under continuous examination without be-
coming dry, to provide a proper and equable
or even higher temperatures to parts or the

whole of organisms, and to add gases to the
fluid surrounding the object. Reckling-
hausen's moist chamber fullils tlie first
requirement ; and Strieker's slide, which is
heated b}^ means of the galvanic current, is
most useful in producing constant anu)unt3
of heat. Strieker's gas-chamber, slide, and
its conducting tubes enable carbonic acid,
oxygen, liydrochl )ric acid, or any t)ther gas
to be applied to the fluid under examination.
A substitute for those complicated pieces of
apparatus, may be made by procuring a flat
strap-shaped piece of metal, to be fixed upen
the stage, witli an aperture near one end corre-
sponding with that in the stage. The sUde
is placed upon this, and a feeble flame of a
spirit-lamp applied to the other end, will
serve to produce the gentle heat required to
set in motion or continue the amoeboid
movements of organisms.

The preparation of many objects requires
the process of dyeing or Staining.

BiBL. Beale, ffotv Sfc. ; Carpenter, Mi-
croscvpe ; Frey, Mikr. ; Strieker, Hist. ;
Gerlach, i6«Z. ; Rutherford, 7/?'s^. ; Mouchet,
Mn. Mic. J. iii. 75 ; Flemming, ScJmltze's
Archiv, ix. 123 ; Gronland, Cornu, and
Rivet, Prep. Micros. {Botanicul), 1871, Qu.
Mic. Jn. 1872, 82; L. Clarke, Phil. Tr.
18ol ; Minot, Mn. M. J. xviii. 97 ; Meyer,
Arch. Mik. An. xiii.; Moseley, Qu. Mic. Jn.
1872, 374, 379; Pritchard, Qu. Mic. Jn.
1872, 380; Ranvier, Hid. tech.; Marsh,
Section-cuHing ; Betz, Schultze\s Archiv, '\x.
101 ; Qu. Mic. Jn. 1873, 343 ; Gibbs, Hist.
1880.

PRESERVATION of microscopic ob-
jects.— Under this head we shall consider
the arrangement of microscopic objects for
permanent preservation, supposing that they
have been prepared (Prepaeation) in
such manner as to render this possible.

Dry objects, or those which exhibit their
structural peculiarities in the dry state. —
These are sometimes mounted alone, at
others when immersed in some preservative
compound.

In the dry and uncovered .state, they are
occasionally mounted upon disks of cork,
leather, or pasteboard, the surface upon
which the object is to be placed being black-
ened by a coating of very fine lamp-black
mixed with warm sfze or gum-water, or by
a piece of dull black paper pasted upon it ;
the simplest way of making the disks is to
paste black paper upon thick soft leather,
and cut out the disks with a punch, like gun-
wads. The object is fastened to the disk with

PEESERVATION.

[ 632 ]

PRESERVATION.

a little solution of marine glvie in naplitlia,
or •vrith pnm. The disks are sold in the
shops. They are usually transfixed Avith a
pin, by which they may be fixed in the
forceps under the microscope, and may be
fastened to the bottom of a box lined with
sheet-cork when not in use. The advantage
of this plan is its simplicity ; its greater dis-
advantage, however, is that the objects are
liable to injury, and become covered with
dust. It answers very well for common
objects, seeds, minute lichens, etc. ; but
when the objects are of value, they should
be mounted in a cell.

The cell may be made of a square piece
of card-board or pasteboard, of suitable
thickness, with a hole punched in the mid-
dle, ffistened to a slide by marine glue or
Canada balsam — the object being fixed to
the slide by a little of either of the above
cements, and a thin glass cover cemented to
the card-board. Or the whole may be fast-
ened together with paste — first a piece of
black paper upon the middle of the slide,
then the perforated square, next the object,
and lastly the cover. The square of paste-
board may be replaced by a glass ring, a
perforated square of glass, or a piece of
sheet gutta-percha.

When the objects are minute or very
thin, the squnre of pasteboard may be dis-
pensed with, and they may be mounted thus :
they are to be laid upon a slide, and a cover
of thin glass placed upon them ; a piece of
paper larger than the cover, with a portion
cut from the middle larger than the object,
is then covered Avitli paste, and a minute or
two allowed to elapse, that the paper may
become thoroughly imbued with it, the
superfluous paste being removed with the
paste-brush ; the paper with the pasted side
downwards is then laid upon the cover and
the adjacent portions of the slide, and gently
pressed with a cloth, that it may be accu-
rately applied to the glass surfaces. The
whole is then allowed to dry. Tlie principal
point in this process is the complete removal
of the superfluous paste before the paper is
applied. If this be not effected, it will be
drawn by capillary attraction between the
cover and the slide, and reaching the object,
will spoil it.

A very secure method of mounting dry
objects which are not altered by heat, con-
sists in laying a ring or square of black
japan upon a slide, the thiclvness of the
layer being adapted to that of the object,
and applying a pretty strong or long-con-

tinued heat until the cement becomes per-
fectly hard when cold. The object is next
placed within the ring, a cover laid on, and
heat applied until the cement becomesliquid.
Gentle pressure then brings the cement and
the margius of the cover into contact ; and
when the cement becomes cold, the cover is
firmly fixed to the slide.

Another method of fastening the cover to
the slide is by the use of electrical cement
and balsam (Cements, p. 150) mixed with
1 or 2 parts of tallow.

Many dry objects can be well preserved by
Mountiny in Canada Balsajn. — When this
is to be done, care must be taken that they
are thoroughly dry ; otherwise they will ac-
quire a milky appearance, from being sur-
rounded by minute drops of water. Some
objects in drying curl up or become de-
formed, although their minute structure
may not be essentially changed ; this may
be prevented by confining them between
two slides tied together with thread, or held
together by india-rubber rings, sealing-wax
applied at the two ends, or by a folded strip
of brass with the ends riveted. If the ob-
jects be of tolerable size, they are then
soaked in oil of turpentine kept in an oint-
ment-pot covered with a lid, for some hours,
or even days, uiitil the air is entirely dis-
placed froni them by the turpentine. The
latter will often also remove the colouring-
matter from some objects, as parts of insects,
which may or may not be desirable ; hence
the duration of" the process must vary
accordingly. A clean slide is then warmed
over the flame of a spirit-lamp, or upon a
stove, and some clear balsam placed in the
middle of it, and rendered more liquid by
further gentle heat; the object is next care-
fully removed from the turpentine with fu'-
ceps, drained and laid upon tlie warm
balsam. Some more balsam is then allowed
to fall from the warm wire (Balsaji)
upon the object ; and when this is well
covered with it, a warmed cover is gently
laid upon its surface. The superfluous bal-
sam then escapes at the sides of the cover;
and this sliould be aided by gentle pressure.
The slide is next maintained at a gentle heat
upon a warm mantelpiece, or a piece of tin-
plate, until when allowed to cool, the bal-
sam is perfectly hard. As soon as this is
the case, the superfluous portions are cut
away or scraped off witli a kuife, the sur-
faces of the glasses cleaned from any residue
by a cloth wetted with turpentine or ben-
zole, and some sealing-wax varnish applied

PRESERVATION.

[ 633 J

PRESERVATION.

to the edges of the cover aud the adjacent
portions of the slide.

The success of the operation depends
mainly npon two circumstances, viz. tlie
object having been tlioroughly dried, and
the exclusion of air-bubbles. The former
constitutes no diilu'iilty, time being all tliat
is n^quired ; but the latter requires that the
object shall previously have been tlioroughly
moistened with the tnrpeutine, aud that the
balsam sliall have been added to the object,
when laid in the balsam upon the slide,
before so much of the turpentine has evapo-
rated as will allow air to enter any minute
cavities in the object. The heat applied
should also be gentle ; and if the direct flame
of a spirit-lamp be used, its application
should be made rather to some portion of
the shde near that upon which the object is
placed, than directly beneatli the object. If
much heat be applied, bubbles of the vapour
of the turpentine wiU often disfigure the
object for a time; but these will vanish as
the object becomes cool.

If air-bubbles have found their way into
the object, the slide must he macerated in
oil of turpentine until the balsam is dissolved
and the object liberated, aud a fresh mount-
ing made.

If the object he large, it must be mounted
in a cell. A glass ring (sold in the shops)
of suitable thickness must first be cemented
to the slide by balsam ; more balsam is
then added until the cavity is filled, the
object next added, and the cover applied.

If the object be minute, its removal for
maceration in the turpentine is not requisite,
and might entail the loss of the object. It
must then be laid upon a slide, a drop or
two of turpentine added, aud the wliole
warmed until no air-bubbles are visible.
The cover is then removed, most of the tur-
pentine drained oft", balsam added from the
warmed wire, and the cover applied as be-
fore : or balsam may be placed upon the slide
near the margin of the applied cover ; and
on applying a continued gentle heat it will
find its" way under the cover, aud replace
the turpentine as it evaporates.

If air-bubbles remain in parts of a minute
object, a cover should be applied, turpentine
added, and the slide held over a lamp until
the turpentine boils, aud the bubbles dis-
appear on cooling. The cover is then re-
moved, most of the turpentine allowed to
evaporate, the balsam added, and the cover
re-applied. Gum dammara may be used
in the same manner as Canada balsam.

Gum and Gh/cerine. — Objects which can-
not be conveniently dried may be mounted
in a solution of gum-arabic in glycerine ;
tlie manipulations are much the same as
with balsam, except that no heat is re-
quired. Glycerine jelly is often used.

Moimting in Liquid. — The structure of
many objects is so altered by drying that
they require to be mounted in some preser-
vative liquid. These, if of considerable size,
must be mounted in glass cells.

The cells may consist of ghiss rings, i. e.
portions cut transversely from pieces of glass
tubes, of various sizes, according to the
dimensions of the objects. In using these,
the ring is first warmed in the flame of a
spirit-lamp, being held by steel forceps ; one
of the ground surfaces of the riug is then
covered with marine glue or balsam pre-
viously melted in the same flame ; the sur-
face of the slide to which the ring is to be
cemented is then heated in the flame, and
whilst it is hot the stirface of the riug coated
with the melted cement is applied to it, and
the riug pressed firmh^, so as to displace
the superfluous portions. When cold, these
are to be removed with the point of a knife;
sometimes a little solution of potash, oil of
turpentine, or naphtha is required for this
purpose. The cell is then complete, ex-
cepting the lid or cover, which consists of
a circular plate of thin glass, of slightly less
diameter than that of tlie outer margin
of the glass ring. The cell is now to be
filled with the preservative liquid, the object
placed in it, and the cover applied, being
made to slide over the upper surface of the
ring, so as to displace any excess of liquid,
and prevent the admission of air-bubbles.
If the quantity of liquid first put into the
cell be not sufficient, more must be added,
until slight excess is present; the superfluous
portions may be removed by a piece of blot-
ting-paper, and tlie margin of the cover aud
ring very carefully wiped clean with a silk
handkerchief, so that the surfaces may be
free irom all traces of the preservative liquid.
The exposed parts of tlie upper surface of
the glass ring, and the adjacent margins of
the cover, are then to be coated lightly with
one of the liquid cements, by means of a
camel's-hair pencil ;_ and when the first coat
is dry, another must be laid on, so that the
edges of the cover and the adjacent parts of
the glass ring may be firmly cemented toge-
ther, aud the cell completely closed, to pre-
vent the evaporation of the contained liquid.
The important points in this process are,

PRESERVATION.

[ 634 ]

PRESERVATION.

that the heated cemeut used to fasten the
ring to the slide must accurately coat every
portion of the two surfaces in apposition,
and that the surfaces to which the liquid
cement is applied must be perfectly clean
and dry, so that the cement may come into
contact with the surfaces of the glass.
Rings of India-rubber and gutta-percha are
very useful instead of glass.

When the objects are very large, the
rings may be conveniently replaced by cells
constructed of slips of glass, arranged so as
to constitute four sides of a box, the bottom
of the box being formed by the slide, and
the top by a plate of thin glass : the pieces
should be cemented together by marine
glue.

Smaller cells may be made with marine
glue, melted, dropped upon a slide and flat-
tened whilst warm with a piece of wetted
glass, the superfluous portions and central
portion cut away with a knife. Should the
marine glue become loosened from the slide,
it may be re-fastened by heat ; and if the
upper surface be not perfectly flat, it may
be made so by grinding with emery-powder
and water upon a plate of metal or upon a
stone.

Minute objects may be mounted in liquid
in a variety of ways, the choice of which
will vary with their nature. They are
genei'ally mounted in shallow cells, the
sides of which are formed by varnish.

The old method consisted in placing
the object upon a slide, adding a drop or
two of the preservative liquid, applying the
glass cover, adding more of the liquid, or
removing excess with blotting-paper, until
the space between the slide and cover was
accurately filled, then applying to the mar-
gin of the cover and the adjacent portions
of the slide a coat of some liquid cement, as
gold-size, asphalt solution, black japan, &c.
Objects thus mounted keep well for a time;
but the cement soon apparently runs into
the space between the cover and the slide,
and the object becomes spoiled. It is often
requisite, however, to mount an cbject in
this way, which may be lying upon a slide,
perhaps in some peculiar position which it
IS important for it to retain ; when this is
the case, the electrical cement with balsam
and tallow should be used; and there is less
fear of change, provided spirit be not used
as the preservative liquid.

^\'henever it is possible, then, a cell- wall
should be previously formed, by laying a
ring or square of one of the liquid cements

upon the slide with a camel's-hair pencil,
and applying a continued heat until it be-
comes thoroughly hard when cold. The
cements genei'ally used are : — asphalt solu-
tion ; gold size with which a little finely
powdered litharge has been well mixed,
immediately applied, as it soon hardens ;
sealing-wax varnish ; solution of marine
glue in naphtha, or of Canada balsam in
benzole or chloroform, or the balsam alone.
Allport's hquid marine glue is very useful.
If the upper surfiices of the rings or squares
formed of these compounds, when thoroughly
dry and hard, be not perfectly flat, they
may be made so by grinding alone, or with
emery and water, upon a piece of metal,
marble, or a stone. The object is then
placed in, the cell, the preservative liquid
added, and the cell closed as above de-
scribed.

The following are the most important
preservative liquids and compounds : —

Thicaites's liquid is thus prepared : to
16 parts of distilled water add 1 part of
rectified spirit, and a few drops of creosote
sufficient to saturate it; stir-in a small c[uan-
tity of prepared chalk, and then filter. With
this liquid mix an equal measure of camphor-
water, and before using, strain througli fine
muslin. Used for preserving freshwater
Algje, as having but little action upon the
endochrome.

Ralfs's liquid. — Prepared with bay-salt
and alum, of each a grain, distilled water
1 oz. ; dissolve. 'Forms a readily prepared
substitute for the former in the preservation
of the Algse (Desmidiaceoe).

Ilantzsch, quoted by Carpenter, produced
a fine preservative medium for minute
Algfe ; composed of 3 parts of alcohol, 2 of
distilled water, and 1 of glycerine ; and the
object, laid in a cement-cell, is covered with
a drop, and placed under a bell-glass. Al-
cohol and wnter evaporate, and leave the
glycerine: more is added time after time,
and the cell is thus filled.

Acetate of alumina. — 1 part of the salt to
4 parts of distilled water. Topping finds
this the best preservative for delicate vege-
table colours.

Distilled tenter. — Very often used for
preserving Algfe; but perhaps camphor-
water would be better.

Camjyhor-icater is prepared by digesting
distilled water with a lump of camphor.

Spirit and water. — Proof-spirit is prepared
by mixing 5 nu>asures of rectified spirit
with 3 of distilled water. It is frequently

PRESERVATION.

[ 635 ]

PRESERVATION.

used for preserving animal structures, or-
gans, injections, &c. Delicate preparations
may be kept in a mixture ot" 1 part of
spirit with 5, or even 10, parts of water.
iJilute spirit sliould never be used as a pre-
serA ative when it can possibly be avoided,
on account of its action upon the cements.
Methylated spirit is very useful, on account
of its cheapness and strengtli ; may be used
when diluted in preserving large specimens
of animal tissue.

Creosote water is prepared by filtering a
saturated solution of creosote in rectihed
spirit, mixed with 20 parts of water. It is
recommended for preserving preparations of
muscle, cellular tissue, tendon, cartilage, &c.

Arscnious acid. — A preservative liquid is
made of this substance by boiling excess of
the acid with water, iilteriug the solution,
and adding 2 parts of water. It is a very
good preservative of animal tissues. Arse-
uite of potash, 1 part dissolved in 100 of
water has been found usefid for preserving
the primitive nerve-tubes.

Corrosive siihliniate. — A dilute solution of
this substance is useful in the case of the
blood-corpuscles, nerve, muscular fibre, &c.

Salt (^chloride of sodium) and water, 5 gr.
to the ounce, was long since recommended
for the preservation of tissues, but is not
much used, because fungi are apt to grow in
it, which might, however, be prevented by
satm'ating it with camphor by digestion.
Corti has found a tolerably concentrated
solution the best preservative for the delicate
structures and nerve-cells of the internal
ear. Carpenter recommends sea-water, with
one tenth part of alcohol and one tenth of
glycerine, for preserving the delicate marine

organisms.

Carbonate of potash. — 1 part dissolved in
from 200 to 500 of distilled water, is a good
preservative of the primitive nerve-tubes.
Solution of acetate of potash is also useful.

Glycerine. — This is the most valuable of
all liquids for vegetable preparations, which
may be closed air-tight or not at pleasure.
Dissections covered with a glass may be
left in it from day to day, remaining un-
changed and always ready for examina-
tion. Objects may be mounted in it, as
with chloride of calcium. It is one of the
most valuable fluids for the preservation
and preparation also of animal tissues.
Camphor-water and naphtha and water may
be added.

Glycerine and Gum {FarranCs com-
pound).— Pure gum-arabic i oz., glycerine

1 oz., water 1 oz., arsenious acid 1} grain;
dissolve the arstiiiious acid in the water,
then the gum, without heat, add the gly-
cerine, and incorporate with great care to
avoid forming bubbles.

(Jum-ivater (see Cicment.s). — The solu-
tion should be very thick, so as to flow with
difficulty from the end of a wire. It may
be used like balsam, but without heat. The
residue is very apt to crack when dry ; this
may be prevented by applying a thick coat-
ing of varnisli around its margins.

Chloride of calcium (Calcium, chloride
of). — Objects may be mounted in this solu-
tion without closing the cell, by pasting
two narrow strips of paper transversely upon
a slide, leaving a greater interval than the
breadth of the object ; the latter is then laid
upon the slide, a small quantity of the solu-
tion added, and a cover applied. The solu-
tion must not touch the paper. The cover
may be fLxed to the paper on the slide by
tiie electrical cement with balsam and tallow.
It is best, however, to close the cell.

Chloride of zinc. This is an excellent pre-
servative of animal tissues for microscopic
examination. It exerts a slight coagulating
action, but this is not sufficient to seriously
impair the peculiarities of the objects, and
large portions of all structures which may
require to be examined should be kept in it.
The ordinary strength is 20 grs. of the fused
chloride to the 1 oz. of water. A lump of
camphor should be kept floating upon the
surface of the solution in the stock-bottle.

Goadhy's solutions. — These are of three
kinds. The first (A) is made with — bay-
salt (coarse sea-salt) 4 oz., alum 2 oz., cor-
rosive sublimate 2 grains, boihng water 1
quart. This is too strong for most pur-
poses, and is only to be employed where
great astringency is required to give form
and support to delicate structures.

The second (B) is made with — bay-salt
4 oz., alum 2 oz., corrosive sublimate 4 gr.,
water 2 quarts. This is recommended for
general use, and as best adapted for perma-
nent preparations. Mr. Thwaites uses it for
marine Algaj ; but we have found chloride
of calcium answer for this purpose, and it is
much more secure. Schultze recommends
it for preserving Medusce, Echiiiodermata,
Annelid larvse, Entomostraca, Diatomacese,
Foraminifera, and Polycystina, both the
hard and the soft parts, and advises the
use of glycerine afterwards to produce
transparence.

When carbonate of lime exists in the

PRESERVATION.

[ 636 ]

PRESERVATION,

preparations, as in the Mollusca, tlie fol-
lowing (C) should be used : — take of bay-
salt 8 oz., corrosive sublimate 2 grains,
water 1 quart. Marine animals require a
stronger liquid (D) of this kind, made by
adding about 2 oz. more salt to the last.

Pacini's modification is made with corro-
sive sublimate 1 part, chloride of sodium
2 parts, glycerine 13 parts, and distilled
water 113 parts. The mixture should be
kept for two months ; and in use, 1 part
should be diluted with 3 parts of water, and
filtered. It is good for the preservation of
blood-corpuscles, nerves, ganglia, and
morbid cell-structures.

iSalici/lic acid. Edwards found that a
saturated solution kept Volvox well.

Deanes compound. — This is made with —
gelatine 1 oz., honey 5 oz., water 5 oz.,
rectified spirit ^ ox., and 6 drops of creosote.
The gelatme is soaked in the water until
soft, the honey added, the mixture then
boiled, and when it has cooled somewhat,
the creosote mixed with the spirit added;
la>;tly, it is filtered through tine flannel.
This is used warm.

That preservative liquid should always be
chosen which exerts least action upon the
structure of the object which it is requnded
to preserve.

If drying the object does not destroy its
peculiar structure, and the object is not very
transparent, the balsam should be used.

If the structure be destroyed by the pro-
cess of drying, and the obj ect be not impaired
by endosmosis, the chloride of calcium or
glycerine is best. Other circumstances may
render these preservatives desirable : thus
the minute parts of the moutli of the Aca-
rina are best seen and preserved in balsam,
Avhilst the general form of the body is best
retained when the animals are immersed in
chloride of calcium or glycerine.

Objects to be mounted in a preservative
liquid should be placed in a watch-glass.
If they are alive they maybe placed in water,
and as much of this as possible should be
poured off or removed with a pipette or
blotting-paper, and the preservative liquid
added, and tliis operation repeated that the
water may be entirely displaced.

The liquid cements used to close the cell
sliould be applied in several layers, each
being allowed to dry before the next is
applied.

The preservative liquid must not bo capa-
ble of exerting any action upon the cements
used in making or closing the cell.

If chloride of calcium or glycerine be used
as the preservative liquid, when the first
coat of liquid c^'ment used to close the cell
has become dry, the slide and cover should
be washed gently with a sponge and di-
stilled water, then dried with blotting-paper
or a silk handkerchief, and the next coat of
varnish applied.

The great difficulty is to permanently
preserve moist objects; for whatever may
be the cement used, watery liquids almost
invariably escape in time, altliough the pre-
parations may remain good for some yeiu's.
No jjerfect cement is known, which on
thoroughly drying retains its hold on the
slide. Objects mounted in glycerine keep
best ; but in many instances the structure is
entirely destroyed by it. This difficulty may
be often overcome, by adding very diluted
glycerine to the object at first, replacing it
gradually by stronger as the water evapo-
rates, until at last the object becomes really
mounted in pure glycerine.

Many moist objects may also be mounted
in balsam or dammara-solution, by lirst
macerating them in weak alcohol, then in
stronger, next in oil of cloves, and finally in
balsam.

Even objects mounted in balsam are not
safe ; for when the balsam becomes really
dry, it separates from the slide, and air runs
in. Balsam thinned with turpentine, and
gradually added, perhaps with the aid of
gentle heat, will, however, restore the ori-
ginal condition. 'And the cement around
older objects should be varnished occa-
sionally with dilute balsam or dammara-
benzole solution.

The deeper the cell, the less the chance
of the object being spoiled.

As soon as objects are mounted, the slides
shoidd be labelled with a square or circular
piece of paper pasted upon them, the name
and other particulars being expressed in
writing. The name &c. may also be
Avritten upon slides with a diamond : but
the paper labels should always be used ;
otherwise much time will be lost in search-
ing for and distinguishing particular objects
in the cabinet.

For preserving dried plants from mould
and. insects, the old method was to brush
them with a solution of a grain or two of
corrosive sublimate dissolved in an ounce
of spirit. The " Kew inixture " for the
same purpose, is made with corrosive sub-
limate and crystallized carboHc acid, of each
I oz., methylated spirit a pint. Perhaps

TRIMITIA.

[ 087 ] rPJMORDIAL UTRICLE.

I of this strenpftli is sufficient for freneral
use. The same may be applied to insects
in the cabinet, by means of a hair-pencil.
Bn-keley points out that carbolic acid alters
the colour of some fungi.

RiBL. Treatise upon the INIicroscope
(liVTROD.) ; Corti, Sieb. und Kiill. Zeit. iii.
1.34 ; Goadby, Amer. J. xiii. 15 ; Davies-
Matthews, Mounting ; Mohl, Bot. Zeit. xv.
249 ; Beale, IIoio ; Carpenter, Microscope ;
Fray, Mikr. ; Strieker, Hid. ; Heys and
Hepworth, Tr. Mic. Sac. 186-5 ; Lawrence,
Qu. Mic. Jn. 1859, 257; Walmsley, Mn.
Mic. Jn. i. 380; Bastian, ibid. i. 94;
Mouchet, ibid. iii. 7o ; B.ichmann, Anf. mik.
Praparat.

PRDII'TIA, .T. & H.— A small fossil
Ostracode with suboblong valves, impressed
with a varialile furrow or pit in the medio-
dorsal region. Forty species in the Silurian
rocks of Britain, Europe, and America.

BiBL. Jones & Hall, Ann. N. H. 3. xvi.
415.

PRIMORDIAL UTRICLE.— This term
indicates a peculiar portion of the contents
of the cellulose sac constituting a vegetable
cell. As the formations comprehended
under this name are of great importance in
the development of vegetable cells, a little
detail must be entered into in explaining
the subject.

If a cell of the pulp of any succulent
fruit, a cell of yeast, or cells in sections
taken fi-om the delicate nascent tissues of
any growing part of plants, are placed in
water, the entire contents will soon be seen
to retract from the cellulose wall, leaving a
clear space, filled with transparent liquid,
between the latter and a sharply detiued
line bounding the contracted or coagulated
contents (PL 47. figs. 1, 2, 10-12). The
addition of tincture of iodine makes the
conditions still more clear. If the parent
cells of pollen-grains or spores are treated
thus, just before the development of the
cellulose wall of the special parent cells (see
Pollen), the four portions of the contents
of the parent cell contract and separate, and
each portion, containing its own granular
stnictures and nucleus, appears bounded by
a well-defined line (fig. 607). This well-
defined line presents in this condition the
appearance of a delicate membrane or pel-
licle enclosing the entire contents. The
action of acids, or spirit, and iodine, reveals
the existence of a similar set of conditions
in all actively vegetating cells ; and in most
cases a more or less thick viscous layer of

the protoplasm is found lining the cellulose
wall before the application of the reiigents.
Since the line indicating the boundary of
the contents cannot be distinctly seen until
the contents have retracted from the cellu-
lose wall, and since the protoplasm is always
coagulated by the action of the reagents, it

Fig. 607.

Fig. 608.

CM-...i

Fig. 607. Parent celJa of pollen-grains jnst after the
separation of the contents into four portions, treated
with iodine. CM, the parent cell. P, the protoplasmic
portions, each with a nucleus and a well-defined outline
at the surface of the primordial utricle. Magnified 250
diameters.

Fig. 608. Cells of Protococcus multiplying. The green
granular contents are bounded by the definite outline
of the primordial utricle : the primary and secondary
cellulose parent-cell membranes are represented as
separated from each other. Magnified 400 diameters.

is a subject of discussion whether the film
forming the well-defined line on the surface
of the contracted contents is a true struc-
ture, or_ only a pellicle produced by the
coagulation of the surface of the protoplasm,
just as a "skin" forms over size, or other
similar substances when they dry up in the
air. ■\'ery young cells often appear tiUed
with a dense protoplasm (young autheridial
cells of Cryptogamia, embryo-sacs of many
flowering plants, cells about to produce
zoospores in the Confervoids, &c.), which
may produce numerous new cells by merely
breaking up into separate portions; and
thus the fvmction of the primordial utricle
is shared by the entire mass of contents.
Young cells of nascent tissues, presenting
this condition at first, acquire the primor-
dial utricle afterwards, simply by the dense
contents becoming excavated as the cell-
wall expands, and following this in its
growth, so that the originally dense homo-
geneous mass becomes a hollow sphere
with the centre occupied by watery cell-
sap; in other cases the originally homo-
geneous protoplasm becomes excavated by
nimierous water-vesicles, and thus honey-
combed, until it forms a mere reticulation
of protoplasmic threads upon the wall or
stretched across the cavity. The proto-
plasmic layer lying upon the wall of the

miTCHAKDIA.

[ 638 ]

PROSTHEMIUM.

cell presents a complex arrangement in
some cases : Braun correctly distinguishes
three layers in Iliidrodictyon ; there are
three in Chara, where the intermediate one
contains the chlorophyll-granules, and the
innermost forms the circulating mass ; a
distinct layer is left after the discharge of
the zoospores in Clad q)}) or a, Sec. Thus, as
explained under the head of CELL-forma-
tion, the primordial utricle or formative
protoplasmic layer is the active agent in
cell-division, and the layer forming the
surface of the isolated portions of contents
of parent cells produces the new cell-wall
in all cases of free-cell formation, whether
taking place in parent cells, or, as in the
case of the zoospores of Algae, after escape
from the latter. Strassburger describes
the primordial utricle as being radiately
striated, especially when treated with osmic
acid.

In many of the Algae, some of the indivi-
dual cells regularly exist for a certain period
as masses of protoplasm devoid of a celkilose
coat, as, for example, the spores of Fuciis
and its allies, and the active zoospores of
Confervoids ; and these bodies, although
presenting a well-defined outline, do not
appear to have a properly developed mem-
brane on the surface, which merely appears
to be denser than the semifluid central por-
tion. These bodies withdraw themselves
evidently from the definition of a vegetable
cell as ordinarily given ; nevertheless they
constitute all the essential living part of a
vegetable cell, and indicate most clearly
the undoubted fact that the cellulose walls,
that is to say all the really solid and per-
manent portions of vegetable structure, are
mere skeleton or shell for the protoplasmic
or nitrogenous structures.

BiBL.^ jMohl, Bot. Zeit. ii. 273; VermiscMe
Schrift. 362; Henfrev, Ann. N. H. xviii.
364; Kfigeli, Zeitsckr. tciss. Bot. 1844 &
1846; Braun, Verji'mg., Bay Soc. 1853,
121 ; Cohn, Nova Acta, xxii. 605 ; Prings-
beim, Bild. d. Pflanzenzelle, 1854 ; Hartig,
Bot. Zeit. xiii. 393; Criiger, j'fiw/. 001 ; Sachs,
Bot. 43 ; Henfrey-Masters, Bot. 495.

PRITCHAR'DIA, Raben.— A genus of
Diatomaceaj, comprising certain species of
Nitzschia and Si/nedra. (Rabenht. Aly. i.
162.)

PROROSCEL'LA, Kt. — A genus of
Ilolotrichous Infusoria. Elongate-clavate,
compressed, with an apical hook ; mouth
ventral ; an undulating membrane between
the front and mouth; with one or more

caudal setse. P. vennina ; maiine length
1-250".

PROEMBRYO.— The term applied to
the structure first produced from the ger-
minal vesicle of Flowering Plants, after im-
pregnation, consisting of the suspensor and
the embryonal cell at its extremity. The
proembryos of the Gymnosperms are espe-
cially remarkable (see Ovule). The same
term is often incorrectly applied to the pro-
thallium, the cellular structure first pro-
duced in the germination of the spores of
the higher Fiowerless Plants.

PROROCEN'TRUM, Ehr.— A genus of
CiHo-flagellate Infusoria.

Char. No eye-spot ; carapace smooth,
terminating in a point in front; flagellum
single.

P. micans (PI. 31. figs. 70 & 71), ovate,
greatly compressed ; length 1-430".

BiBL. Ehr. Inf. 44 ; Ulap. et Lach. Infus.
411: Kent, /??/.' 461.

PROR'OD(Ji\, Elir.— A genus of Holo-
trichous Infusoria, family Tracheliua.

Char. Body covered with vibratile cilia,
truncate in front ; mouth with a cylinder of
teeth ; freshwater. Species numerous.

P. teres (PI. 31. fig. 72). Body ovate,
terete, white. Length 1-140".

BiBL. Ehr. Inf. 315; Clap, et Lach.
Infus. 318 ; Kent, Inf. 491.

PROSEN'CHYMA. See Tissues, Ve-
getable.

PROSTHE'MIUM, Kunze. — A genus
of Melauconiei (Coniomycetous Fungi),
growing upon the branches of trees, form-
ing circular depressed spots ; the perithecia

Fig. 609.

Prosthemium betulinum.

Spores and paraphj-ses seen in a rertical section of fruit.

Magnified 200 diama.

enclose erect articulated filaments bearing
radiating tufts of two or three septate spores
(fig. ()09). P. bcfidhunn occurs upon tlie
bark of the branches of the birch tree. The
species are mere forms of Sithceriacei,

PKOTAMCEBA.

[ 639 ]

PROTOCOCCUS.

EiBL. Berkeley, Urit. Flor, ii. pt. 2. p.
297.

PROTAMCE'BA, Haeckel.— A genua of
Protista.

Char. A simple shapeless protoplasm-
body witliout vacuoles, ■with simple pseudo-
podia, not ramifying nor anastomosing ; re-
production by Ussion.

Species. Protamaha priinitii'a. Proto-
plasm-body of 0'03-0"05 millim. diameter,
continually varying in form, with one or
several (3 to 6) peripheral pseudopodia.
Processes short, rounded, obtuse, hnger-
shaped, at most as long as the diameter of
the central body. Freshwater, near Jena.
(Haeckel, Oen. 'Moiyhol. 186G, i. 133.)

PROTEA'CE.E.— A family of Dicotyle-
donous plants, mostly from New Holland
or the Cape, shrubs or small trees (Banhsia,
Grevillea, Haliea, &c.), of remarkably rigid,
evergreen habit. The coriaceous leaves are
well suited for the study of the epidermal
structures ; and the stomata have interesting
peculiarities (see Stomata). The epider-
mis is often scurfy with scattered hairs,
some of which are of curious forms (PI. 28.
fig. 29).

PKOTEON'INA, Williamson.— A simple
Ai'enaceous Foraminifer ; a feeble Lituola of
the Haplophragmiujn group.

BiBL. Williamson, Foram. 1 ; Ctii-penter,
For. 309.

PEOTEUS.— An old uame applied to
certain Infusoria, as Amoeba &c. Also a
genus of Amphibia with large blood-cor-
puscles.

PROTHAL'LUS or PROTHALLIUM.
— The structure resulting from the germi-
nation of the spores of the Cryptogamia, in
which the female, and sometimes the male
organs are formed. See Marsileace^,
Lycopodiace^, Equisetace^, and Ferns.

PROTISTA, Haeckel.— A kingdom of
organic nature supposed to be intermediate
between the animal and vegetable king-
doms, and comprising the so-called lowest
forms of life. It is divided into the follow-
ing groups : —

t\. Gymnomonera {Frofogenes, Fro-
tamosba, &c.).
I. Monera. -< 2. Lepomonera {Protomonas, Vam-
I j>yreUa,Protomyia,Muxiiatrum,

{ &c.).

(I. Nudiflagellata (Euglena, Spon-
TT -171 „ 11 <■„ ' rlu/o7iiorui:t,&c.).

II. ^lageUata.^ ^ Cilioflagellata (Peridinium, Ce-
( ratiuni, &c.).

III. Labjrinthulea {Laltyrinthula).

IV. Diatomea (Bacillaria).

V. PhycochromacejE.-

VI. Fungi.

VIII. Protoplasta (AmoBboida).-i

'1. Chrysococcacea (Glce-

ocapea, Merismopae-

dia, &c.).

2. Oscillarinca (Nosfocha-

j ceu ,Itivulariacea, &c.).

'1. Phycomycetes {SuprolegniecB, Mu-

corine(P, &c.).

2. Hypodermiee ( LVediTKE, Usiilagince,
&c.).

3. Basidiomycetes {Hymenomycetes ,
Giistroniycefes, &c.).

4. Asconiycetes (Protomycetes, Disco-
, mycetes, &c.).

VII. Myxoniycetes (Mycetozoa).

(1. Gymnamcebae
(Aulij»ioeba, &c.).

2. Iiepamceb;e (Ar-
celhi, TJiJJlugia,
&c.).

3. Gregari ee
( (^Gregarina).

IX. Noctilucee KocHlvca.

(I. Acyttaria (Monothalamia and
I Polythalamia).

X. Ehizopoda.-i 2. Heliozoa [Acfinosphanwii).

3. Eadiularia (Monocytharia and
\ Polycytharia).

BiBL. Haeckel, Gen. Morpli. ; Mon. Mo-
neren, Jenai. Zeit. 6. iv. I ; Biol. Studien,
1 ; Wright and Kirby, Qu. 3Iic. Jn. 1869 &
1871 ; Kent, Lif. 44.

PROTOCOC'CUS, Ag.— A genus of Vol-
vocineee (Confervoid Algae), at present very
imperfectly known, since without a toler-
ably complete history of the development
of the forms it is impossible to distinguish
the true species of Protococcus from the
young states of the more complicated Pal-
mellaceee, and even from the germinating
gonidia of the Lichens. As we have limited
it, Protococcus includes those unicellular
Algas which in the aquatic state consist of
single zoospore-like bodies, with a more or
less evident gelatinous cellulose envelope
through which the two cilia protrude.
They move actively, and are multiplied by
division during the active state. Finally
they settle down into a resting-stage ; and
they may then increase by vegetation so as
to form granular patches. Mostly, however,
those which settle down tm-n red and ac-
quire a thick coat, passing through a stage
of rest before they germinate again, appa-
rently requiring to be dried up first, "\^'hen
they germinate, they frequently produce
many generations of still forms before the
active cDiated forms reappear, especially
when placed on damp surfaces, and not in
water. When placed in favourable circum-
stances, the resting-forms (even after several
years) recommence the course of vegeta-
tion, reacquiring the green colour by de-
grees in the course of several generations of
vegetative cells. The contents of the red

PROTOCOCCUS.

[ 640 ]

PROTOMYCES.

form appear to consist partly of oil-glo-
biiles ; in the green form the protoplasmic
substance is colom-ed by chlorophyll^ and at
a certain stage contains starch.

We have traced P. viridis through all
these stages, as represented in PI. 7. fig.
2 a-g : a most elaborate monograph of P.
pluvialis by Cohn goes to establish the same
conclusion, that the genus Hcematococcus is
founded on states of Protococcus. The P.
viridis of our figures is undoubtedly C/da-
midomonas, synonymous with Disc/mis, Du-
jardin. This form appears at first sight
nearly allied to Euglena; but there are
striking differences in the appearance and
moyements of the active forms, and the
vegetative forms are somewhat different.
It may be remarked, however, that the
zoospores of Protococcus viridis, allowed to
dry upon a slide, often turn red and look
just like small Astasice (PL 7. fig. 2 g).

We have remarked under Palmella,
that the Polar red snow appears to be a
Palmella (PL 7. fig. 'id), although this
species has been called Protococcus and
Hcsmatococcus nivalis ; and it appears to us
that Shuttleworth and others have con-
founded this with Protococcus 2^^uvialis.
Hassall's species of HcEinatococcus, nos, 8 to
19, with the exception of H. vulgaris (Chlo-
rococcum) fPl. 7. fig. 1), are probably con-
generic with our P. viridis.

Our P. viridis makes its appearance com-
monly on damp earth, sand, kc, forming a
greenish coat of no perceptible thickness;
and the zoospores (Chlamidomonas) occur
constantly in standing pools in spring and
autumn, tinging the surface of the water
bright green, and, as they settle to rest,
forming a kind of green scum at the mar-
gins, constituting the green matter of
Priestley. Cells of resting-form 1-2400"
in diameter. P. ^yluvialis colours water red
in like manner ; it occurs on mountains,
especially in melted snow-water. Cells of
resting-form 1-1250 to 1-625" in diameter.
Similar colorations, however, are produced
by various other organisms (see Water).

It may be observed that when the active
forms of P. viridis and P. pluvialis divide
without coming to rest, they produce forms
which are imdistinguishable from many of
Ehrenberg's species of Polygastrica. When
they acquire a loose cellulose coat before
losing their cilia, they represent Gyges ; at
other times they resemble Chlorogonium,
Uvella, Polytoma, Manas, Bodo, Sec.

BiBL. Ilarvej^, Br. Alg. 1. 180 ; Ilassall,

Fr. Alg. 821 ; Meneghini, Tr. Turin Ac. 2.
V. 1 ; Cohn, Nova Acta, xxn. 605, Pag Soc.
1853, 514 ; Von Flotow, Nova Acta, xx.
414 ; Braun, Verjilngung, Ray Soc. 1853,
206 ; Nageli, Einzellige Algen ; Ktitzing, Sp.
Alg. 196 ; Tab. P/igc. i. ; Rabenh. Alg. iii.
56 ; Cooke, Fr. loai. Algce, 1882. See also
Red Snow.

PROTODER'MA, Ktz.— Agenus of Ul-
vacese (Confervoid Alg.ie).

Char. Cells forming a thin membrano-
crustaceous expansion ; they are roundish
angular. P. viride (PL 3. 'fig. 18), fresh-
water; on stones; cells 1-300".

BiBL. Ktz. Phyc. Gen. 295: Rabenht,
Alq. iii. 307.

PROTOG'ENES, HaeckeL— A genus of
Protista.

Char. A simple shapeless protoplasm body
without vacuoles, which protrudes ramify-
ing and anastomosing processes, and repro-
duces itself by fission. Protogenes priiuor-
dialis. Body sometimes globular,from 1-200-
1-25" diameter, sometimes extended and
flattened out, with irregular outline, to 1-10"
diameter ; pseudopodia exceedingly nume-
rous, over a thousand, very fine, with very
numerous ramifications and anastomoses.
Mediterranean.

BtBL. Haeckel, Zeitschr. iciss. Zool. xv.
1865, 360.

PROTOHY'DRA, Greef— A genus of
Zoophytes, Like Hydra ; but simpler in
structure, as it has no tentacles. Reproduc-
tion by transverse fission ; nematophores and
pigment-cells present.

BiBL. Greef, Sieh. u. Kdll. Zeit. i. 1870 ;
Qu. Mic. Jn. 1870, 297.

PROTOM'ONAS, Haeckel.— A genus of
Protista.

Char. A simple protoplast, without
vacuoles, simple or ramifying pseudopodia.
Reproduction by zoospores, which combine
into meshes or plasmodia.

Protomonas amyli. In decaying Nitella.
(Haeckel, Gen. Mmph. vol. ii. 23, Qu. Mic.
Jn. 1869.)

PROTOM'YCES, Unger.— A genus of
Fungi, the affinities of which are very
doubtful ; placed in Ascomycetes by Sachs,
but apparently forming a degraded branch
of Phycomycetes. They grow in the inter-
cellidar passages of leaves and leaf-stalks.
According to De Bary, these Fungi consist
of ramified filaments creeping between the
cells of soft tissues, and swelling up at inter-
vals (apparently where they meet an inter-
cellular space large enough), to form globular

PKOTOMYXA.

[ 641 ]

PROTOZOA.

spores : a filanumt with several spores in
course of di\ isioii appears like a varicose
tube ; it is septate, however; and when the
glolMilar spores are mature, they have a
double coat; in P. 7uacrosjK>rns the diameter
of the ripe spore is about l-oOOO". When
advanced in age, the mycelium appears to be
wholly converted into spores, which become
free. " The existence of these Fungi is ren-
dered more or less evident externally by
warty projections of the epidermis, finally
bursting. Unger describes four species — i*.
macrosponts occurring on ^l^</opodium and
AmieUca, P. encJnyoms (Galii) occurring on
Galiiuii mollugo, P. mkrosporus on Rannn-
ctilus repens, and P. Paridis on Paris qua-
drifolia. Do Bary found a species on 3Ie-
njianfhes, with oval spores 1-800" long and
1-1 ."JOO" broad. A species {P. conconutaiis)
has lately been found on exotic Orchids.

BiBL. Unger, Exanthem. d. Pftanz. 341 ;
D^ Bary, Brandpitze, 15, pis. 1 & 2, and
Beifriuie,\. 18G4 ; Leveille, Ann. Sc. Nat. 3.
viii. 374; Tulasne, ibid. vii. 112; Fries,
Sum. Ve(/. ol7.

PROTOMYX'A, Haeckel.— A genus of
Protista.

C/iar. A simple shapeless mass of proto-
plasm, with vacuoles, which protrudes rami-
t'viug and anastomosing pseudopodia. lie-
production by zoospores, forming plas-
modia.

Protomy.ra aurantiaca, orano;e-red ; resting
condition globular, with a thick structure-
less covering. Zoospores pear-shaped, with
a strong ilagellum at the pointed end, at first
moving like the zoospores of the Myxo-
nij-cetes, afterwards creeping like an Amaha.

genus of ^lyxomycetes. P. coprinarius, in
the intestines of man, cows &c. ; amoeboid
bodies not uniting. (Cunningham, Qu.
Miv. Jn. 1881 ; Kent, Inf. 472.)

PROTOPLASM.— Tlie name appHed by
Mohl to the colourless or yellowish, homo-
geneous or granular viscid substance, of
nitrogenous constitution, which constitutes
the formative substance in the contents of
ACgetable cells, in the condition of gelatinous
strata, reticulated threads, and nuclear aggre-
gations &c. It is the same substance as that
termed by Dujardin in animals Saecode.

Protoplasm is the simplest form which
organized matter can assume, and which,
without any otjier material pecidiarities
except a certain softness, transparency,- and

jelly-lilce condition, iscapable of contracting,
expanding, and assimilating. It is common
to the animal and vegetable kingdoms.
See Cell, Sarcode, and Pkimokdial

UTRICLE.

PROTOSPON'GIA, Kt.— A genus of
Ohoano-flagellate Infusoria. Ovate, imbed-
ded in a gelatinous matrix ; Uagellum single.
P. Hacchelii ; length 1-3000' ; freshwater.
(Kent, Inf. .363.)

PROTOZO'A.— A Subkingdom of the
Animal Kingdom, characterized by the
absence of distinct organs, the form and
simple organization being reduced to those
of a cell (Siebold). If the above definition
be adopted, it must be remembered that the
cell may be represented by the cell-contents
only ; and these we believe to constitute the
essential part of a cell (see Edition 18oG_),
which is now generally admitted.

The Protozoa form the lowest group of
the Animal Kingdom. They are mostly
minute, and aquatic, consisting of a mass of
gelatinous protoplasm or sarcode. This is
usually granular, often containing minute
globules of fat, sometimes minute crystalline
particles. Sometimes one or more nuclei
are present, often they are absent. The body
is naked in some, in others it is enveloped
in a carapace or shell, which may be simply
membranous, calcareous, as in the Forami-
nifera, or siliceous, as in the Poly cystina and
Aca7ithometrce. Movement is eilected by
pseudopodia, which are short and stout, or
long and slender, processes of the protoplasm,
sometimes branching and anastomosing to
form meshes or plasmodia ; by cilia; or by
flagelhform filaments. There is no proper
gastric cavity. The food-particles are in the
lowest forms entangled and brought to the
body by the pseudopodia, as in Amoeba and
Actinophrys &c., or ingested from all parts
of the surface ; while in many Infusoria there
is a distinct mouth and anus. Contractile
vesicles supposed to represent a circulatory
apparatus are sometimes, but not always
present. Reproduction is produced by fission,
by conj ugation, or by the breaking-up of the
nucleus.

The Protozoa approach closely the lower
and simpler forms of the Vegetable Kingdom ;
and very different views are held as to the
characters by which they may be distin-
guished, and the organisms which belong to
the two kingdoms.

An older character was, that animals
subsist upon ingested organized matter,
while plants prepare their food from un-

2t

PSAMMOSPH.ERA.

[ G42 ]

PSILOTE.E.

organized materials, as carbonic acid and
ammonia. The other, that animals absorb
oxygen and evolve carbonic acid, while
plants evolve oxygen, cannot be applied
generally in the case of these microscopic
organisms. But certain Protozoa have no
mouth, and cannot admit food-particles like
Ainoehci, nor can organic matters be endos-
mosed by them. Movement has in late
years been shown to be a property of pi'oto-
plasm, limited where a cell-wall is present,
yet it may be said to be universal. Stein
and Kent consider the presence of a contrac-
tile vesicle to form a distinctive character ;
but its existence in Volvox, we think must
invalidate tliis view.

The chemical property of the protoplasm,
that of animals swelling and dissolving in
solution of potash or ammonia, Avhile tliat
of plants is apparently unaffected, has also
been called in aid ; and this really appears
to be the best individual test. Little atten-
tion has been paid to this part of the question,
so that the older views must remain, until
further experiments have been made. See
Animal Kingdom, and the heads of the
Classes.

BiEL. Siebold, Verffl.An.i.;^och,Icon.
Hist. 1865 ; Gabriel, Gegcnlaur's Morph.
Jahrb. 1875 ; Mereschowski, Hussl. Arch.
mik. An. 1878, xvi. : Butschli, Brotm's Klass.
^■c. ; Kent, Inf. 1880, 31.

PS.UIMOS'PH^'RA, Schultze. — An
Arenaceous Foraminifer, round, free or
attached, made of coarse sand-grains and
fine cement ; common in deep seas. (Brady,
Qu. Mic. Jn., new ser. xix. 8.)

PSECA'UIUM, Eeuss.— A globose or
Glanduline Maryinulina. Fossil.

BiBL. Eeuss, "-S"//-. Ak. Wien, xliv. 368.

PSEUDOCALA'^^US, Boeck.— A genus
of marine Copepoda. 2 sp. (Brady, Cty;^';}.,
Hay Soc. i. 44.)

PSEUDOCH'LAMYS, Clap, et Each.—
A genus of Arcellina (Rhizopoda). P. ni-
lelln ; carapace brown, pseudopodia broad
and short ; in ponds. (Claparede et Lachm.
Inf. 443.)

PSEUDOCYC'LOPS,Brady.— Agenusof
marineCopepoda. 2sp. (Bradv,^©;)^^^ i. 81.)

PSEUDOCYTH'ERE, G. O. Sars.— One
of the C]iihvrida>\ valves very thin, obliquely
quadrangular ; five joints in upper, seven in
lower antenufc, which are long and have
long setije ; no eyes. 1 British species.

BiBL. Bradv, Linn. Tr. xxvi. J53.

PSEUDODIFFLUGIA, Schlum. — A
genus of Arcellina.

Char. Shell membranous, ovoid or ovo-
globular, smooth or striped spirally, with a
wide round opening whence issue pseudo-
podia. (Pritchard, Inftisoria, p. 557.)

PSEUDOGONIDIA.— A term applied to
bodies appearing in the interior of cells of
Algfe, which are obscure in their nature,
being either metamorphosed and isolated
masses of protoplasm, or parasitic bodies
resembling monads. They are apparently
connected with the objects called Chytei-
DiUM and Pythium. (Cienkowski, Princ/s-
heim's Jahrb. Bot.'i. .371.)

PSEUBOG'RAPHIS, Nyl.— A genus of
Microlichens parasitic on Lecanoras.

Char. Spores colourless or becoming
brown, 4-6-locular, sometimes becoming
submuriform ; slightlv blue with iodine.

BiBL. Lindsav, Qit. Mic. Jn. 1869, 352.

PSEUDOPODIA are the processes of
protoplasm which are protruded from the
bodies of the Rhizopoda, serving for loco-
motion and the prehension of food.

PSEUDOS'PORA, Cien.— A genus of
Flagellate Infusoria. Body naked, swimming
or creeping; flagella two, equal ; no mouth.
P. volvocis, on and in Volvox; length
1-12^'^0". (Kent, Inf. 304.)

PSEUDOSPORES. — The apparent
spores of Uredinei and TremcUini, -^hich
germinate and produce the real reproductive
spores, which are then called sporiola.

PSICHOHOR':\IIUM, Ktz.— This genus
consists of species of Confeita, whose fila-
ments are more or less incrusted with oxide
of iron or carbonate of hme.

Bibb. Rabenh. Fl. Ear. Ah/, iii. 324.

PSILO'KIA, Fr.— A genus "of Sepedoniei
(Hyphomycetous Fungi), consisting of little
compact tufts of twisted filaments, at
first covering the fusiform, globose, or oval
spores, which arise from the wart-like pro-
tuberances on the central filaments, ai:d
soon become fi-ee. They are found on dead
wood or on reeds. P. nivea, which is com-
mon on the bark of beech-trees, is the
product of an insect, Adch/es fagi.

BiBL. Berk. i?r. J7. ii.'pt."2."353 ; Ann.
N. II. 2. viii. 17U ; Fries, Sum. Vet/. 405.

PSILOTE.E.— A family of Lycopodia-
ceous plants, distinguished by their many-
celled sporanges, varj'ing much in habit and
external appearance.

Si/nop,sis of Genera.

Psilotum. Sporanges ses.-ile, three-celled,
busting imperfectly into three valves by a
vertical craclc, filled with mealy spores.

PSILOTE/E.

[ 043 ]

PTEiaUE^E,

Tmesipferis. Sporanpfes sessile, three-
celled, buvsting iiiipovfectlv into two v<alves
by a vertical crack, lillcd with nioaly spores.
' Isoetes. Sporani>-es imbedded in the bases
of the leaves, and adnate at the back, not
valvate, with sevenil transverse septa ; con-
taining two kinds of spores (iu distinct spo-
rangia).

Fig. 610,

Pbilotum iriquftium.
Nat. size.

Fig, Gil.

Fragment of a branch of Fsilotum triqui'trum.
Magnified 10 diameters.

PSILOT'RICIIA, St,— A genus of ITy-
potrichous Infusoria. Bodyoblong, flattened,
with 2 rows of long ventral, and a peripheral
row of setae, but no styles. P. acuminata,
freshwater. (Kent, Inf. (572.)

PSILO'TUM, Swartz. {Lycopodium nu-
dum, Ij. ). — An exotic genus of P.'^iloteaj (Ly-
copodiaceoe), remarkable for their trilocular
capsules and minute leaves (fig. 611 ).

PSORO'MA, Nyl.— A genus of Lichena-
ceous Lichens, with large distinct gonidia.

BiBL. Leighton, Lick. Flora, 14'J.

PSOROP'TES, Gervais.— A genus of
Arachnida, of the order Acarina, and family
Acarea.

Char. Body soft, depre.«sed, with rigid
hairs beneath, and on the legs.

Parasitic upon the horse and sheep, and
the ox.

P. equi (PL 6. fig. 18), itch-insect of the
horse. Found upon the scaly crusts formed
upon the body. Mandibles elongate, didac-
tyle, each terminated by two teeth; palpi
three-jointed, and adherent to the labium;
ventral surface covered with parallel undu-
lating rugae ; at the end of the body are
two fleshy lobes, terminated by a tuft of setae,

BiBL. 'Hering, Nov. Act. xviii. 585; Ger-
vais, Walclienners Aptcres, iii. 266; Dujar-
din, Micr. 147 ; Murray, Ec. Ent. 307 ;
Megnin, Paras. 189.

PSOROSPERMI^.— These bodies were
discovered by Miiller, and appear to repre-
sent the pseudo-naviculaj of the Greyarinm
of fishes.

They are microscopic, oval, depressed, or
di.scoidal corpuscles, with or without a tail,
exhibiting no movements, and con.si.stiug of
a tolerably firm outer coat, containing one
or two oblong contiguous vesicles at that
end of the body opposite the tail. They are
about 1-2500 to J -2000" in length, and are
contained in immense numbers in minute
cysts, in almost every part of the body of
fishes, as upon the gills, in the muscles, and
between the coats of the eye, in the swim-
ming-bladder, &c. Sometimes they are
imbedded in a ramified sarcodic mass.

Diameter of the cysts on the pike 1-50 to
1-25" ; of the corpuscles, length 1-2000",
breadth 1-3500". See Pebrine.

BiBL. Muller, Archiv, 1841. 477, 1842,
193; Creplin, ibid. 1842. 61; Dujardin,
Helminthes, 643; Leydig, Mi'dl. Archiv,
1851, 221, Mic. Jn. 1853, i, 200; Robin,
Ve(jet. Parasit. 2. 291.

PTERID'E^.— A family of Polypodia-
ceous F.ems. Genera:

2x2

PTERIDE^.

[ 644 ]

PTEROPTUS.

Adiontum. Sori marginal, linear or glo-
bose, numerous and distinct, or couiiuent.
Indui^ium shaped liked the sorus, formed of
the reflexed margin of the fronds, witli the
capsules beneath.

Ochropteris. Sori marginal, transversely
oblong, at the apices of the lobes of the
segments. Indusium the same shape as the
frond, formed of its retlexed marg-in.

LoncJiitis. Sori marginal, in the sinuses of
the frond, reuiform or elongated. Indusium
shaped like the sorus, membranous, formed
of the frond.

Hypoh'pis. Sori marginal, in the sinuses
of the frond, small, subglobose, uniform.
Indusium formed of the reflexed margin,
membranous.

CheiUmthes. Sori terminal or nearly so on
the veins, at first small, subglobose, after-
wards confluent. Indusium formed from
the changed reflexed margin, roimdish, or
confluent, not quite continuous.

Casseheera. Sori terminal on the veins,
globose or oblong, not reaching beyond the
branches of a single vein. Indusium in-
serted within the margin, and separate from
it, shaped like the sorus.

Oynjchmm. Sori on a continuous linear
receptacle, connecting the apices of several
veins. Indusium parallel with the margin
of the segments, linear, opposite, pressed
over the sori, the edge nearly or quite
reaching the midrib.

Lhivca. Sori linear, occupying the
whole length of the changed pod-like seg-
ments of the upper part of the frond. In-
dusium the same shape, rolled over and
concealing them.

Cryptofiramma. Sterile and fertile fronds
usually diflerent, from the same root ; sori
terminal on the veins, at fii'st sidjglobose, then
confluent, the continuous indusium formed
of the changed iurolled margin of tlie frond.

Pellci-a. Sori intramarginal, terminal on
the veins, at fu'st dot-like or decurrent on
the veins, then running into a line. Indu-
sium formed of the more or less changed
edge of the frond, continuous, sometimes
very narrow.

Pteris. Sori marginal, linear, continuous,
occupying a slender filiform receptacle in
the axis of the indusium. Indusium the
shape of the sorus, usually membranous, at
first covering it, then spreading.

Ceratopteris. Sori placed on two or three
veins which run longitudinally down the
frond, and which are nearly parallel Avilh
both the edge and the midrib. Indu-

sium formed of the reflexed margin of the
frond, those of the two sides meeting at the
midrib.

Lomaria. Sori linear, continuous, lon-
gitudinal, and occupying the space between
the midrib and the edge. Indusium mem-
branous, formed of the revolute margin of
the frond.

PTERIS, Linn.— A genus of Pteridefe
(Polypodiaceous Ferns), represented by one
indigenous species, Pteris aquilina, the com-
mon Brake Fern ; numerous tropical species.
(Hooker, Syn. 153.)

Fig. 612.

Pteris,

A pinnule with marginal indusiate sori.

Magnified 10 diameters.

PTEROCOM'MA, Buckt.— A genus of
Aphidfe. P. p//os«, on willow-twigs. (Buck-
ton, Aj^hida;, Pay Soc. ii. 142.)

PTERODI'NA, Ehr.— A genus of Rota-
toria, of the family Brachionsea.

Char. Eyes two, frontal; foot simply
styliform. At the end of the tail-like foot
is a suctorial disk ; jaws with the teeth
either arranged in a row, or two teeth only
in each.

Three species; two freshwater, one
marine.

P. patina (PI. 44. fig. 20). Testula mem-
branous, orbicular, cry.^talline, roughish
near the broad margin ; a depression pre-
sent between the rotatory lobes. Fresh-
water; length 1-120".

BiBL. Ehreuberg, /»/?<«. 51 0; Pritchard,
Inf.lW.

■pTEROP'TI'S, Dufour. — A genus of
Acarina (Arachnida), family Gamasea.

Char. Body depressed ; last joint of palpi
longest ;. legs stout, with short joints.

P. vespertilionis (PI. 6. fig. 39). Found

TTERYGIUM.

[ 645 ]

PUOCINIA.

upon bats. Several species have been de-
scribed.

BiBL. Gervais, WalcJcenaer^s Aptbres, iii.
227 ; Dufour, Ann. Sc. N. xvi. 98, xxv. 9 ;
Koch, Deutschl. Crustac. ; Murrav, Ec. Ent,
175.

PTERYGIUM, Nyl. -A genus of Colle-
niaceous Liclieus. 2 species, ou calcareous
rocks. (Leio-liton, Lichen Fl. 12.)

PTERYGO'NIUxAI, Sw. — A genus of
Alosses. See Neckeea.

PTILIDIUM, Nees.— A genus of Jun-
germanuiete (Ilepaticte), containing one ele-
gant British species, P. ciliare, frequent on
heaths and rocks in subalpine districts, but
rarelv found in fruit.

BiBL. Hooker, Br. Fl. ii. 126; Br. Jung.
pi. Co ; Ekart, Juny. pi. 5. fig. 36.

PTILO'TA, Ag. — A genus of Ceramiacefe
(Florideons Algfe), with flat feathery fronds
a few inches high ; of a deep red colour,
growing on Laminarm or Fuci, or on rocks
between tide-marks. The fructification
consists of: — 1. clustered roimdish favell<e
containing spores, terminating the ultimate
pinnules, and surrounded by an involucre
of subulate ramuli, or naked ; 2. tetrahedral
tetraspores on short pedicels fringing the
pinnules. Antheridia have not been ob-
served. F. plumosa (PI. 4. fig. 16).

BiBL. Harvey, Mar. Alg. 159, pi. 22 A ;
Flnjc. Br. pi. 70 ; Greville, Aly. Br. pi. 16 ;
Niigeli, Algensi/stem, pi. 6. figs. 38-42.

PTYCHOG'RAPHA, Nyl.— A genus of
Graphidei (Lichenaceous Lichens). 1 sp.,
on decorticated mountain-ash. (Leighton,
Lich. Fl. 392.)

PTYCIIOS'TOMUM, St.— A genus of
Holotrichous Infusoria. Free, ovate, un-
svmmetrical, mouth ventral. 2 species, in
the intestines of Aunulata (Tubifex), and
MoUusca {Pahulina). (Kent, Inf. 541.)

PTYGU'RA, Ehr.— A genus of Rotatoria,
of the family Ichthydina.

Char. Eyes none; no hairs upon the
body ; tail-like foot cylindrical, simply trun-
cate.

Teeth three in each jaw ; anus* situated
at the end of the tail-like foot.

P. melicerta (PL 44. fig. 21). Body terete-
clavate, turgid in front, hyaline ; mouth
with two little hook-like horns ; cervical
process single and smooth. Freshwater ;
length 1-144". Ehrenberg questions whe-
ther this is not a young form of another
geniis.

BiBL. Ehrenberg, Inf. 387 ; Hudson,
Mn. M. Jn. xiv. 165.

PTYXID'IUM, Perty.— A genus of Eu-
chelia. It shoidd probably be included in
Leucophrys.

BiRL. Pritchard, Infusoria, p. 615.

PUCCIN'IA, Persobn.— A genus ofUre-
dinoi (Ilypodermous Fungi), containing
numerous parasitical species, growing upon
the leaves and other herbaceous parts of the
higher plants, forming "mildews," and Avith
their Uredinous forms, "rusts" &c. Tliese
Fungi have received considerable attention
lately from Tulasno, l)e Bary, and others ;
and it appears that the genera Uredo and
others have no distinct existence, but are
preparatory forms of Puccinia and other
genera noticed under Uredinei. In the
article iEciDiUM w^e have described the
twofold reproductive structures, namely the
spermogonia and the perithecia (figs. 6 & 6 a,
p. 19 ; PL 26. figs. 1-4), producing respect-
ively the spermatia (supposed to have the
office of spermatozoids) and the spores. In
Puccinia three forms of reproductive organs
occur : first, spermogonia analogous to those
of ALcidium ; then the forms called Uredines
(chiefly of the supposed genus Trichohasis),
producing globular unilocular bodies, shortly
stalked, and with transparent walls, but
with yellov/ or orange-coloured contents ;
and lastly the true Puccinice, containing
bilocuLar spores borne on short stalks, and
having a dark-brown integument. The
latter present remarkable phenomena in
germination, which may be best observed
in those which sprout without becoming
detached from the matrix, such as P. gra-
minis, which however rem.aiu quiescent
until the spring foUoAving their development,
whUe P. Glecho)n(e,Buxi, Dia}dhi, sinAotliers
germinate in the same summer. The bilo-
cidar spores have each one pore (analogous
to the pores of PoLLEN-grains), from which
extends a filamentous process, ultimately
giving rise to four short processes, each
terminating in a pointed process bearing a
sporidium, of more or less curved elliptical
form. About the time when these fall off",
the filament bearing the four processes be-
comes divided by septa into four chambers,
but then appeal's to die. The sporidia ger-
minate and produce a filament, which, in-
stead of becoming the basis of a mv'celium,
reproduces a sporidium smaller than the first.
More is said respecting these remarkable
organisms under the head of Uredinei.

The Puccinice present the following ge-
neral characters : — The spermogonia rare,
scattered on either face of the infested leaf.

PULEX.

[ G46 ]

PULEX.

with an immersed, ostiolate peridiole, bear-
ing long cilia at the mouth ; pale, orange,
or blackish in colour. The Urediuous fruits
are scattered or grouped in circles, devoid
of a proper peridium, but surrounded some-
times by thickish cylindrical paraphyses,
very rarely connected below into a mem-
brane, forming a kind of ciliated peridium ;
the stylospores are round and mostly spinu-
lose, with three or four equidistant pores.
The Puccineous fruits are also scattered or
grouped in circles, sometimes containing
only their proper spores, sometimes with
Uredinous spores intermixed, destitute of a
proper peridium, but, lilie the Ureclines,
having sometimes a false envelope formed
of continent paraphyses ; their spores, form-
ing the chief distinctive character of the
genus, are biloculai; oblong or globose,
rounded-obtuse or acuminate at the apex,
smooth or spinulose, the upper locidus with
a pore at its summit, the lower with a pore at
the upper end of one side (next the septum).
These plants occur commonly on the
Grasses and many otlier herbaceous plants,
often changing colour during the summer,
being yellow or orange when the Uredinous
spores are ripe, and afterwards blackish
when the Puccineous form is matin-e.

The species are very numerous ; but some
of those formerly included under this name
are now removed to other genera, such as
Uromyces, Triphragmimn, Sec. (See Ure-
DiNEi.) P. yraininis is common on corn
and other grasses (Mildetv) ; among the
other frequent species are P. Caricis, Poly-
yonorum, Mentlice, Anemones, Buxi, &c.
Robin describes a Pi(cci>u'a, apparently on
the authority of Ardsten, a Swedish phy-
sician, found upon the human head in Favi^s.
From his description it appears to be a true
Puechiia, and should hold its place (P. Favi,
Ardst.) among the species. But Avhat is
more remarkable, it occurs together with
Achoriun ScJianleimi, the latter presenting
itself as a constituent of the cups or crusts,
while the Puccinia occurs afterwards on the
desquamations of the epidermis.

BiBL. Berk. Br. Fl. ii. pt. 2. 303 ; Ann.
N. H. vi. 439; ibid. 2. v. 4G2, xiii. 461;
Tulasne, Ann. Sc. Knt. 3. vii. 12; ibid. 4. ii.
77, l.'W & 182; Levcille, ibid. 3. viii. 309;
De liary, Brandpihe, 30 ; Fries, Sum. Vey,
513; Pvobin, Veyct. Pa rasif. 2. (Jl3; Bagnis,
Jn. Mic. Soc. 1878, i. 27.

PULEX, Linn. (Flea).— A genus of In-
sects, of the order Siphonaptera (Suctoria
or Aphaniptera), and family Pulicidse.

CImr. As there are only the single family
and genus in the order, the characters of
the latter are distinctive.

Head small (PL 35. fig. 9), compressed,
rounded above, truncate in front, in some
species with an inferior pectinate fiinge of
blackish-brown teeth ; eyes one on each
side, round, simple, smooth ; behind each
eye is a cavity or depression, at the bottom
of which the antennse are attached ; an-
tennfe (figs. 9 a, 12) four-jointed, their form
varying in the difR-rent species, the third
joint very minute, and forming the cup-
shaped base of the terminal joint or piece,
which in some species is furnished with
numerous transverse incisions, representing
as many distinct joints; in some the an-
tennae extend out of the depres^-ion, and are
carried erect.

Oral appendages (PI. 35. fig. 9 e) compos:^d
of several parts : 1 . (PL 33. figs. 32 d, 33 d)
The uppermost is single, and consists of a
thin, flattened seta, coars*4y toothed on the
upper surface, and traversed throughout its
entire length by a canal, upon the walls of
which a very slender trachea runs, and from
which very minute canals, terminating at
the end of the little teeth, are given ofl".
This is the suctorial organ, and perhaps
corresponds to the labrum, but is sometimes
regarded as the lingua or ligula. 2. (figs.
32/, 33/) Two quadrangular, narrow, and
elongated plates, each furnished with longi-
tudinal ribs, and with fine teeth ; these are
the lancets or scalpella, and correspond to
the mandibles. 3. (PL 33. fig. 32 y) Two
somewhat triangular or leaf-like plates, the
maxillae ; to which are attached — 4. ( PL 33.
fig. 32 h ; PL 35. fig. 9 d) Two nearly cylin-
drical four-jointed maxillary palpi. 5. (PI.
33. fig. 32 Jc ; fig. 33 Jc) Two labial palpi, in
the form of sheaths, four-jointed, thickened
at the back and membranous at the margin ;
these palpi arise from near the apex of —
6. (PL 33. fig. 33 /) A small membranous
labium, with the still smaller mentum (PL
33. fig. 33 7n) at its base.

Thorax composed of three segments, each
consisting of an upper (PL 35. fig. 9, c), and
a lower piece //; from the lower arise the
corresponding legs. The two posterior seg-
ments of the thoi'ax aroeach furnished with
a pair of plates, the hindermost of which is
longest, and nearly covers the sides of the
first and part of the second abdominal seg-
ment (fig. 9, behind /,/) ; these represent
rudimentary wings.

The legs are large, especially the hinder

rULEX.

C G-J- ]

PULEX.

ones, and adapted for leaping. The first
joint or coxa (//) is very thick; the second
or trochanter (/■;) is very small ; next come
the fomnr (/), the tibia {h), and lastly the
five-jointed tarsns (/), which is terniiuated
by two curved and denticulate claws, with
a lobe or heel at the base.

The abdomen of the female has nine
distinct rings, the first seven of which are
each furnished with a pair of stigmata («),
and consist of horny arches with mem-
branous margins. The eighth arch, which
has no membranous margin, is strengthened
by a horny band furnished with fine hairs,
to protect the orifice of the last stigma.
The ninth and last segment, called the
pygidium (fig. 9x and PI. 1. fig. 13), is
somewhat kidney - shaped or two - lobed,
folded on the dorsum, and exhibits twenty-
five to twenty-eight stift' and longish bris-
tles, implanted in the centre of as many
disk-like areoloj, each of which is orna-
mented with a ring of rectangular or some-
what cuneate rays. The poi-tions of the
pygidium between the areolpe are studded
with minute spines. The end of the abdo-
men in the female (PL 3o. fig. 9) is more
rounded or ovate than that of the male
(fig. lo), which is somewhat tm-ned up-
wards.

In some species the segments of the
thorax and abdomen are furnished with a
posterior pectinate fringe.

The alimentary canal is short and straight;
the stomach cylindrical ; the small intestine
as long as the stomach, and the large intes-
tine short. Four short and broad Malpighian
vessels open into the lower orifice of the
stomach; and the ducts of tw-o round salivary
vesicles unite to a single canal ascending in
a coiled form on each side of the oesophagus
towards the mouth.

The eggs of the flea are white, elongated,
and viscid outside. The larvas have no
legs ; they are elongated, resembling minute
wonns, and very active, coiling themselves
into a circle or spiral, and serpentine in
their movements. The head is scaly, with-
out eyes, and supporting two very minute
antennae ; the body has thirteen segments,
with small tufts of hairs, and at the end of
the last are two little hooks.

The species are numerous (twenty-five,
Gervais) ; but their characters are not well
defined. One spades (P. terrestris) is said
to exist under brush-wood; and one (P,
Boldi) in Boleti.

P. irritans, human flea. Pitch-brown ;

head shining, smooth, pectinate fringe ab-
sent ; legs pale ; femora of posterior legs
with hairs inside ; second joint of the tarsi
of the auterittr pair of legs and first joint
of posterior tarsi longest. Tarsal joints, in
respective order of greatest length : an-
terior, 2, 5, 1, 3, 4 ; posterior, 1, 5, 2, 3, 4
(Bouche). We have not been able to find
a flea with the above relative length of the
joints of the anterior tarsi.

P. /('//s, cat's flea (P. canis, Bouche; PI.
35. fig. 9). Pale pitch-brown ; head naked,
shining, smooth, with delicate scattered
dots ; coxa3 and femora almost naked ;
fifth joint of anterior tarsi and first joint
of posterior tarsi longest. Tarsal joints:
anterior, 5, 2, 1, 3, 4; posterior, 1, 2, 5,
3, 4.

P. cams or serraticeps,^e?i of dog and fox
{P.felis, Bouche ; PL 35. fig. 10, head.}. Pale
pitch-brown ; head shining, smooth, punc-
tate behind ; lower part of head and pro-
thorax with a pectinate fringe ; posterior
tibiiB much expanded at the end ; fifth
joint of anterior and first of posterior tarsi
longest. Tarsi : anterior, 5, 2, 1, 3, 4 ; pos-
terior, 1, 5, 2, 3, 4.

P. (jallince, fowl's flea. Pitch-brown,
with shining, smooth, elongated head ; pro-
thorax with a pectinate fringe; first joint
of all the tarsi longest. Tarsi : anterior and
posterior, 1, 2, 5, 3, 4.

P. mnrtis, flea of the marten and dog.
Postero-inferior margin of head and pro-
thorax with pectinate fringe ; tarsi as in P.
cams.

P. sciuri, flea of the squirrel. Head
naked ; pectinate fringe on prothorax, none
upon the abdomen. Tarsi : anterior, 1, 6,
2, 3, 4 ; posterior, 1, 2, o, 3, 4.

P. erinacei, flea of hedgehog. Head
naked, mesothorax with a fringe. Tarsi :
anterior, 5, 2, 1, 3, 4 ; posterior, 1, 2, 5, 3, 4.

P. iaipce, CuL'tis, flea of mole (PI. 35.
fig. 24).

P. colmnhfp, pigeon's flea. Prothorax
with pectinate fringe, none upon the abdo-
men ; antennfe o.f male erect, those of the
female lying in the depression.

P. penetrans {Rhijnchoprion), the chigoe or
jigger. The females burrow in the skin of
the feet ; and the ova, undergoing develop-
ment, enlarge the parent-abdomen to the
size of a pea, causing severe inflammation,
&c. Rostrum very long. Tropical.

P. ve>>peiiilioms, flea of the bat (PL 35.
fig. 11, head) ; the first seven segments of
the abdomen with pectinate fringes.

PULLENIA.

[ 648 ]

PUSTULirOP.A.

p. pipistrellee. The two first and the '
seventh segments only with teeth.

BiBL. \\'esU\ood, Intr. ii. 489; Bouch^,
jVov. Act. 1835, xvii. 501 ; Duges, Ann.
Sc. N. 1832, xxvii. 165 ; Gervais, Walcke-
naer's Apt. iii. 362; Denny, A7m. N. H.
1843, xii. 315; Laudois, An. d. Hunde-
Flohs, ISi-u ; Furlmig, it/?«. Mic. Jn. 1872,
263 ; M^gnin, Paras. 00 ; Tascheuberg, B.
Flohe, 1880.

PULLE'NIA, Parker & Jones.— A mi-
nute, globose, glassy, nautiloid Foraminifer,
near iilohiyerina ; showing usually 4 or 5
chambers and a transverse slit-like aper-
ture ; an isomorph of Nonionina. Recent
and fossil.

BiBL. Carpenter, Introd. For. 184.

PUL VINULI'NA, Parker & Jones.— One
of the typical Rotalid<e. Shell with 7-30
cells ; dense and delicately tubuliferous,
often limbate, sometimes prickly, granulate,
and stellate ; usually biconvex \F. repanda,
PI. 24. tig. 16); sometimes outspread, and
vermiculate (P. vermicular is, PL 24. fig. 11);
septa single, little trace of canal-system ;
aperture large, arched or notched ; septal
face often coarsely perforated. Very nume-
rous species, recent and fossil.

BiBL. Carpenter, For. 310; Parker and
Jones, Phil. Tr. civ. 390.

PUNCTA'EIA, GreviUe.— A genus of
Punctariacese (Pucoid Algse), containing
three (one doubtful) British species, P. la-
tifolia,plantu(finea, and tcnuiasima, growing
on rocks and stones, consisting of membra-
nous, olive or brown, ribless fronds, 4 to 12"
long, 1 to 3" broad, having a shield-like
organ of attachment at the base. The fruc-
tilication consists of sori scattered all over
the fronds in minute distinct dots, com-
posed of roundish sporanges (producing
zoospores) intermixed with paraphyses;
these sporanges are called spores in most
works.

BiBL. Harvey, Mar. Alg. 41 and Pkijc.
Brit. ; GreviUe, Alq. Brit. pi. 9.

PUNCTAlllACEyE. -A family of Fu-
coideje. Root a minute naked disk ; frond
cylindrical, or flat, unbranched, cellular,
with ovate sjuiranr/es intermixed with jointed
threads in groups on the surface. British
Genera :

Pimctaria. Frond flat and leaf-like.
Sporanijes scattered or in sori.

Asperococcns. Frond membranous, tubu-
lar, either cylindrical or compressed. Spo-
ranf/es in dot-like sori.

Litosiphon. Frond cartilaginous, fili-

form, subsolid. Sporanges scattered, almost
solitary.

PUS,— Popularly known as "matter;"
one of the products of inflammatory exuda-
tion.

Its general properties are too well known
to require description. Pus consists of an
albuminous liquid, containing a number of
minute corpuscles in suspension. These
consist of molecules and granules composed
of proteine compounds, fat or the earthy
phosphates, globules of fat of very various
sizes, and the proper pus-corpuscles or leu-
cocytes. Pus-corpuscles (PI. 38. fig. 4) are
spherical, from 1-2500 to 1-3500" in dia-
meter ; presenting a granular appearance on
the surface, and containing a number of
larger or smaller granules and a small
quantity of liquid. They are undistinguish-
able from the Avhite corpuscles of the blood,
and may be considered as leucocytes. They
possess as protoplasmic masses the power
of spontaneous movement; and migrate in
the tissues. They multiply by division.
When treated with acetic acid, they swell
up, and the granules become excessively
transparent, and ultimately vanish (PI. 38.
fig. 5), leaving from one to five, generally
two or three, round or oval nuclei, which
mostly present a dark margin and light
centre, giving them a cupped appearance,
indicating a diminution of refractive power
in the centre. The cupped centre is some-
times seen in the nuclei without acetic
acid, after the action of water only.

In the pus of chronic abscesses, unhealthy
ulcers, &c. the corpuscles are often few, de-
formed and mixed with numerous granules
of proteine, fatty and calcareous matters,
crystals of cholesterine, of the ammonio-
phosphate of magnesia, and sometimes
monads and vibrios ; exudation-corpuscles
are occasionally present also.

Pi/oid corpuscles. ■ — ■ Under this term
Lebert describes a modification of pus-cor-
puscles, consisting of a tolerably transparent
envelope, enclosing from eight to ten or
more small globules (PL 38. tig. 0). Acetic
acid does not alter them, or at most only
renders them slightly more transparent.
The small globules are composed of a pro-
teiue-compound ; for i\wy are soluble in
potash.

BiBL. That of CHKMiSTRy, Animal; and
Lebert, Phys. Path. ; llindileisch, Path.
Hist. ; Green, Morb. Anat.

See Inflammation.

PUSTULIP'ORA, Blainville.— A genus

PYCNIDIA.

[ 049 ]

PYXICOLA.

of Infundibiilate Cyclostomatous Polyzoa,
family Tubulii)oridoe,

Char. Zoary erect, cylindrical ; cells half-
immersed, arranged on all sides ; orifices
prominent.

Two British species — P. proboscidea, and
P. defli'.va. The latter common on shells
from deep water.

13iBL. Johnston, Br. Zooph. 278 ; Gosse,
Mar. Zoo/, ii. 8,

PYCNIDIA.— A term applied to the
receptacles enclosing stt/lospores in the
Lichens and Fuxgi.

PYCNOG'ONUM.— A genus of Podo-
somata, Sea Spiders, which are usually
placed amongst the Crustacea, but by some
authors amongst the Arachnida. They have
no special respiratory organs, and only four
pairs of legs. They sprawl over seaweed,
and hide under stones. There is a pair of
chelate mandibles.

PYCNOPHY'CUS, Kutz.— A genus of
Fucace;B (Fucoid Algfe), containing one
British species, P. (Fucus) tubercidatus; re-
moved from Fucus on account of its cylin-
drical frond, the compact cellular substance
of the receptacles, and the ramified fibrous
pseudo-root. The fructifications, formed at
the ends of the dichotomous lobes of the
frond, are elongate, cylindrical, more or less
tuberculated, and with numerous pores
opening from couceptacles containing spoj-e-
sacs and antheridia (together), resembling
in general those of Fucus. The spore-sacs
are collected at the bottom of the coucep-
tacles, the antheridia at the upper part.
See Fucrs.

BiBL. Harvey, Mar. Alg. 18 ; Phijc. Br.
89; Decaisne and Thuret, Ann. Sc. N. 3.
iii. 5 ; Thuret, ibid. xvi. 10.

PYGID'lUM.— The last segment of the
ahdomen of certain insects. It exhibits a
curious structure in Pulex (p. G47) ; the
same is stated to occur also in Chrysopa,
the lace-winged flv, the locust &c. (l)avis,
Jn. Mic. Soc. 1879, ii. 252.)

PYRAMID'IUM, Bridel.— A genus of
Funariacese (Acrocarpous Mosses), allied to
Funaria in habit, but differing in important
points.

Pyramidium tetragomtm, Brid. = Gymno-
stomum tetragonum, Schwiigi".

PYRENID'IUM, Nyl.— A genus of Col-
lemaceous Lichens.

Char. Thallus minute, stellato-divided ;
apothecia pyrenocarpous, verrucarioid. P.
actincllum; on chalk. (Leighton, Lich. Fl.
36.)

PYRENODEI.— A series of Lichenacei.

Char. Fructification in closed receptacles.

BuiL. Leigliton, Lich. Flora, p. 2.

PYRENOMYCE'TES.— That portion of
the Ascomycetous and Coniomycetous Fungi
having a closed, nuclear fruit ; standing
opposed to the Discomycetes, with open
fruits, like the Angiocarpous and Gymno-
carpous Lichens. Now sunk in Sphteriacei.

PYRENOP'SIS, Nyl.— Ageuus of Col-
lemaceous Lichens. 8 species ; on rocks.
(Leigliton, Lich. Flora, 14.)

PYRENO'THEA, Fries.— A genus of
Liniborieee (Angiocarpous Lichens), con-
taining a number of species separated from
Verrucaria, on account of the spores being
free in the perithecia and not developed in
thecEe. The bodies taken for spores, how-
ever, are spermatia contained in spermo-
gonia, the sporiferous perithecia being
apparently unknown (see LICHE^^s).

BiBL. Leighton, Aug. Lichens, 65; Tu-
lasne, Ann. Sc. N. 3. xviii. 217.

PYRSONE'MA, Leidy.— A genus of
Holotrichous Infusoria. Body fusiform,
with a cord-like longitudinal undulating
border. P. vertens, in the intestine of the
white axit{Termes); length 1-200". (Kent,
Lnf. 554.)

'PYRULI'NA, D'Orb. — A neat acuto-
pyriform Pohjmorphina. Fossil in the
Chalk, and German Tertiaries.

BiBL. D'Oibigny, Mem. Soc. Geol. Fr.
iv. 43 ; Bradv, Parker and Jones, Litui. Tr.
xxvii. 219. '

PYTIIIUM, Pringsheira. — A supposed
genus of parasitic Unicellular Algfe, the
true nature of which, how^ever, is yet
doubtful.

P. cntophyt,um (PI. 5. fig. 8) occurs in
this country in diseased cells of Confervoid
Algae. It consists of minute flask-shaped
bodies, taking the place of the proper cell-
contents, finally pushing the neck-like por-
tion through the wall of the cells, outside
of which it bursts and discharges active (?)
molecules, which Pringsheim regards as
gonidia. P. viGnospermum grows upon
insects in water, in the manner of Achlya ;
and he refers this genus to the family
Saprolegniece.

BiBL. Pringsheim^ Jahrb, iviss. Bot. i.
289; Carter, Ann. N. II. 2. xvii. 101;
Henfrey, Tr. Mic. Soc. New Series, vii. 25;
Currev, Mic. Jn. v. 211 ; Rabenht. Alg. iii,
276.

PYXICOLA, Kt.— A genus of Peritri-
chous Infusoria; like Cvthurnia, but with

PYXIDICULA.

[ C50 ]

QUININE.

an operculum. Several species ; fresh and
salt water. (Kent, Inf. 725.)

PYXIDICULA, Ehr.— A genus of Dia-
toraacefe.

Chca: Frustiiles single, free or sessile ;
valves circular, convex, hoop absent.

Numerous species have been described —
one f r. wat., one marine, the remainder fossil,
found in America.

Kabenhorst reduces the species to P. major,
adriatica, and a doubtful form, P. Naeyelii.

P. major (PI. 25. tig. 1.3). Valves coni-
cal, regularly punctate. Diameter 1-420" ;
freshwater.

P. adriatica. Fr. se.-sile ; valves nearly
hemispherical, free from markings (ord. ill.).
Upon marine Algae. Diam. l-GOO".

P. m{)ior=CycIotella operculata.

The bodies represented in PI. 2o. fig. 12,
found in ilint, have been described as P.
(/lobator, Pritch. (not P. globosus, Ehr.) ;
they do not, however, appear to belong to
the Diatomacese.

Kiitzing places Stephanopy.vis and Xan-
thiojyyxis here.

BiBL. Ehr. Inf. 165, and Per. Perl. Ah.
1844 & 1845 ; Klitz. Bacill. 51, and Sp. AJfj.
21 ; Pritchard, Inf 432.

PYXID'lUM, ' Kt.— Like Opercularia,
but solitary. Two species ; freshwater ;
on Entomostraca and Confervse. (Kent,

Inf. asm:)

PYXILLA, Grev. — A genus of Diato-
macese.

BiBL. Grev. Mic. Trans. 1-865, 2.

Q.

QUARTZ. See Rocks.

QUILL. — The quill of feathers possesses
considerable polarizing power; the coloured
bands, however, are so broad that they are
better seen with the naked eye.

See Feathebs,

QUININE. See Alkaloids.

lodo-disulp/iafe, sulphate of iodo-quinine,
Herapathite. — This remarkable salt is pre-
pared by dissolving disulphato of quinine in
strong acetic acid, warming the solution,
dropping into it an alcoholic solution of
iodine carefnily in small quantities at a
time, and placing the mixture aside for
some hours, when tlie crystals separate.

They dissolve in the heated mother-liquor,
also in hot alcohol, being again deposited
on cooling ; but they are not soluble in cold
alcohol or ether.

They are so easily decomposed and alt<n'ed,
that they are with diliiculty mounted. This

may, howe-^-er, be effected by cautiously
neutralizing tlie excess of acid in the mother-
liquor b}' solution of ammonia, taking care
not to precipitate the excess of the disulphate
of quinine ; a portion of the liquid contain-
ing the crystals is then transferred to a slide,
the liquid removed with blotting-paper, and
the crystals dried in a current of cold air.
They are then moimted in Canada balsam
rendered thin with ether, heat being avoided.

The crystals are of a pale olive-green
colour (Pi. 11. fig. 17), and possess a more
intense polarizing power than any other
known substance. The play of colours pre-
sented when they are rolling over each other
whilst contained in a watch-glass, forms a
very beautiful sight, the colours varying
according to the relative positions of the
crystals to each other ; and when the latter
cross each other at a right angle, complete
blackness is produced.

lierapath, who discovered this beautiful
salt, has described a method of making
crystals of sufficient size to replace tourma-
lines or Nicol's prisms. The ingredients
are : — as pure disulphate of quinine as can
be obtained, that from Howard and Kent
being best ; strong acetic acid, of sp. gr.
1"042 ; proof spii-it composed of equal bulks
of rectified spirit of sp. gr. 'SS? and dis-
tilled Avater ; and tincture of iodine, made
by dissolving 40 grains of iodine in 1 oz, of
rectified spu-it. The p-"oportion3 are :

Disulphate of quinine. . 50 grains.

Acetic acid 2 fiuid ounces.

Proof spirit 2 fluid ounces.

Tincture of iodine .... 60 drops.

The disulphate of quinine is dissolved in the
acetic acid mixed with the spirit, the solu-
tion heated to 130° F., and the tincture of
iodine immediately added in drops, the
mixture being constantly agitated.

The compound should be prepared in a
wide-mouthed Florence flask ; and the tem-
perature should be maintained for a little
time after the addition of the iodine, so that
the solution may become perfectly clear,
and of a dark sherry-colour. It should
then be set aside to crystallize in a room of
a imiform temperature of 45° to 50° F.,
and kept from vibration. The latter may be
efll'cted by suspending the flask by the neck
witli strong string, attaching this to a hori-
zontal cord stretching across the room from
one wall to the other ; or placing the flask
on a steady support, lying upon a pillow.
The large crystalline plates form upon the

QUIXQUELOCULIXA.

[ Gol ]

RALFSIA.

surface of tlie liquid, where tliey are allowed
to remain for twelve to twenty-four liours,
until they have acquired sufilcieut tliicluiess.
The fla^k is then carefully removed without
shaking, and rested upou a gallipot. A
circular cover is next fastened by its edge to
the end of a glass rod with a little wax or
marine glue, and passed beneath oue of the
crystalline films, the adherent mother-liquor
removed with blotting-paper, and the lilm
allowed to dry in a room at a temperature
of 45° to oO°"F. The cover and film are
then placed under a small bell-glass, with a
watch-glass containing a few drops of
tincture of iodine. The time required for
the iodizing may be about three hours at
50° F., or less if the temperature be higher.
The tilni is then covered with a solution
of Canada balsam in ether, saturated with
iodine by warming with a few crystals of
this substance, and allowing it to cool.

Other lilms are removed and moimted in
the same manner. Should the films not
separate from the original liquid at the end
of six hours, this must be heated with a
spirit-lamp until the deposited crystals are
dissolved, a little spirit and a few drops
more tincture of iodine added, and the
liquid again set aside.

If the film appear black when removed
on the cover, it is crossed by an adherent or
interposed crystal, which must be carefully
removed.

These crystals are sold ready mounted,
and may be purchased at a very small cost.
Herapath proposes the production of the
crystal of the quinine-salt as a very delicate
test for the presence of quinine. A test-
liquid is first made with 3 drachms of
acetic acid, 1 drachm of rectified spirit, and
6 drops of dilute sulphuric acid. A drop of
this is placed upon a slide and the alkaloid
added, and, when it is dissolved, a very
minute quantity of tinctm'e of iodine added ;
after a time the salt separates in little
rosettes.

BiBL. Herapath, Phil. Maq. 1852, iii.
161, iv. 186, and 18o3, vi. 171 & 346;
Haidinger, ihid. 1853, vi. 284.

QUIXQUELOCULIXA, D'Orb. — One
of the modifications of Miliola, having its
chambers aggregated on two opposing faces,
as in Sjyiroloculina, but with their edges
more extended on the one side than on the
other, so that only three chambers are ap-
parent on one side, and fve on the other.
Xumerous QuinqiielocuHnai occur recent
and fossil. Q. fendnidum (PI, 23. fig, 5)

ia common in the European seas. Q.
Bronf/marfii (fig. 6), having delicate striaj,
is not uncommon in warmer seas.

IJiBL. Williamson, Foratn. 85 (Miliolina);
Carpenter, Fur, 78,

R.

RACO'DIUM. See Antennabia,

EACOMIT'RIUM = TRiciiosTOMr>r pt.

RADIOLA'RIA, Miiller.— An order of
Rhizopoda, including the Polycystina,
Acantliometrina, Thalassicollida, and Acti-
nophryina. They possess a siliceous test or
sihceous spicules, a central capsule and
peculiar yellow cells, and are provided with
long, protruding, radiating pseudopodia
which occasionally form meshes. See the
Families and Rhizopoda.

BiBL. Haeckel, Badiolarien, 1862 ; Greef,
Arch. mik. An. 1869, 1875.

RAD'ULA, Dumort. — A genus of Jun-
germanniese (Hepaticfe), containing one
British species, R. complanata (fig. 613),

Fi^, 613,

Eadula complanata.

Leafy shoot with an immature and a burst capsule.

Magniiied 5 diameters,

common upon the trunks of trees, every-
where, forming orbicular pale-green patches
closely appressed to the bark,

BiBL. Hook. Br. Jung. pi. 81 ; Br. Flor.
ii. pt. 1. p. 120 ; Ekart, Syn. Jung. pi. 4,
fig, 31 ; Endlicher, Gen. Plant., Supp. 1,
Xo. 472. 13 ; Leitgeb, Ber. Wien. Ak. 1871.

RAD'ULUM.— A genus of Ilydnei (Hy-
menomycetous Fungi), consisting of a few
species with irregular compressed teeth or
rude irregular tubercles. R. orhictdare is
not infrequent on fallen branches of birch
and other trees, assuming various foiTQS.

BiBL. Fr. El. 148; Berk, Outl. 263;
Cooke, HnndlK .304,

RALF'SIA, Berk. — A genus of Myrione-

RAMALINA.

[ 6r,2 ]

RAPHIDES.

macepe (Fucoid Algse), containing one Bri-
tish species, Ji. verrucosa {H. deusta, Berk.),
forming cTark-brown I^ichen-like patches, 1
to 6" in diameter, on rocks between tide-
marks. The fronds are at lirst orbicnlar and
concentrically zoned ; they are composed of
densely packed, vertical, simple,jointed fila-
ments. The fruit is formed in wart-like
patches, and consists of obovate sporanges
attached to the bases of vertical filaments.

BiBL. Harvey, liar. Ale/. 49.

RAMALINA, Ach. — A genus of Rama-
loidei (Lichenaceous Lichens), containing
13 British species, of shi'ubby habit, mostly
growing upon the trunks of trees, bearing
orbicular-peltate apothecia, nearly of the
same colour as the thallus. R. fraxinea,
fastu/iata, and farinacea are common.

BJBL. Hook. JBr. Fl. ii. pt. 1. 228;
Tulasne, Ann. So. Nat. 3. xvii. 192.

RAMULI'NA, R. Jones.— A tubular
branching Il3'aline Foraminifer, swollen
here and there into chambers, whence the
branches or stolouiferous tubes proceed at
varying angles to other such chambers. H.
aciileata, D'Orb., it. Iccvis, and hrachiatn,
Jones, are known from the Chalk ; Ii. (/lobu-
lifeva, Brady, has a wide distribution in the
Atlantic and Pacific.

BiBL. Rupert Jones, Proc. Self ad X. F.
Club, 1875, n. ser. i. 88 ; Brady, Jn. Mic.
Soc. n. ser. xix. 272,

RA'NA, Linn. See Frog.

RAPH'IDES.— This name was first ap-
plied to the minute needle-shaped crystals
occurring in great abundance in the tissues
of many plants; but it is now generally
applied to all the crystalline formations
contained in vegetable cells. The crystals
are either solitary or grouped ; and some-
times the groups are formed on a peculiar
stalked matrix projecting into the cavity of
enlarged cells, forming the organs called
ci/sfoliths.

There are few plants of the higher classes
which do not contain raphides : they are
very abundant in the herbaceous structures
of the Monocotyledons generally, and espe-
cially those of tile Aracea3, Musacefe, Lilia-
ceae, &c. ; they also abound in the Polygo-
naceee, Cactaceae, Euphorbiacefe, Urticacena,
&c., among the Dicotyledons. They are
usually found only in the interior of the
cavities of cells, but in some cases they occur
in the intercellular cavities, or in the cell-
walls. They may occur in almost any
part, but are found most extensively in the
stems of herbaceous plants (Monocotyledons

in general and Cactacese); they also occur
in the bark and pith of many woody plants
(lime, vine) ; leaves hkewise frequently con-
tain them in vast numbers (Aracese, Mu-
saceae, Liliacea;, Iridacese, Polygonaceae) ;
also sepals (Orchidaceae, Geraniaceae) ; in
the rhubarbs, and also in Umbelhferse, they
occur extensively in the roots, for instance
in the carrot ; and they abound in autumn
in the base of the bulbs of the onion and
other Liliacete. Raphides are often very
readily discovered and clearly seen in tissues,
by the aid of the polarizing apparatus.

The form of the needle-shaped raphides
is usually that of a square prism with pyra-
midal ends. These ordinarily occur lying
parallel in bundles (fig. G14) ; another com-
mon form is that of rectangular or rhombic
prisms with oblique or pyramidal ends ; the
smaller of these often present themselves in
groups radiating fi-om a centre (fig. 615).
Prisms of similar or of six-sided forms,
octahedra, rhombs, &c. also occur singly or
few together (PI. 48. fig. 28), the larger
ones sometimes nearly filling the cavity of

Fig. ni4.

Fig. 615.

Fig. (U4. Parenchymatous cells of the stem of Rumour,
containing bundles of raphides. Magnified 400 diam^.

Fig. 61o. Purenchymatoiis cells of tlie stem of Beta,
with groups of raphides (Sphaeraphides). MaguiUed
400 diams.

the cells in which they lie. Rhombic
crystals of oxalate of lime occur in the
parenchjnnatous cells surrounding the vas-
cular bundles in the bracts of Medicago
tri{/onclla ; and CTulliver has shown the
crystal in each cell of the testa of the elm.
The cells containing the bundles of acicular
raphid(>s in the Aracese also contain a viscid
sap, which causes them to burst, through
eudosmose, when placed in water, and dis-

RAPIIIDES.

[ 653 ]

EATTULUS.

charge the crystals. Turpiu erroneously i Jn. 186(
described these as organs of a special nature,
under the name of Biforines.

Kapliides most frequently consist of oxa-
late of lime, especially in the Cactacea;,
Poljgonacea^, &c. ; carbonate of lime seems
to stand next in the order of frequency,
mostl}' in the form of granules, only recog-
nizable under polarized light witli the
crossed uicols ; then sulphate and phosphate
of lime. Their composition may be ascer-
tained by the appropriate tests for these
salts. It is sometimes difficult to determine
the form accurately, on account of the small
size ; it is found advantageous to mount
well-cleaned and partly crushed crystals in
Canada bals:im, also to Aiew them roUing
over in alcohol (Inte. p. xxxiii).

The pecidiar crystalline structures called
cystoUthSj occur most abimdantly in the
families of the Urticaceas (including Morepe)
and the Acauthacefe. They ordinarily con-
sist of a stalked, clavate, and globose, or
irregular linear body, suspended in a greatly
enlarged cell, most frequently situated
beneath the epidermis of the leaf (PI. 48.
figs. 26, 27) ; but they also occur in deeper-
seated regions. Their nature and develop-
ment liave been followed by several ob-
servers ; and they are found to consist of a
cellulose matrix with carbonate of lime crys-
tallized in a kind of efflorescence upon the
surface. They appear to originate by a little
papilla or column of secondary deposit at
the upper end of the cell, which increases
by successive concentric layers of cellulose
applied on the lower surface, leaving a short
stalk-hke portion which remains uncovered
and also free from the crystals which gradu-
ally sprout out from the thickened head.
The crystals may be removed by the action
of acid ; and then the matrix assumes a blue
colour with sulphuric acid and iodine. Payen
imagined the thicker portion incrusted by
the crystals to be composed of numerous
cellules, each producing a crystal : this is
erroneous. The cystoliths yaxy in form :
the clavate kinds may be best observed in
Ficus elastica (PI. 48. fig. 27) and other
species, in vertical sections of the leaf;
globular forais are found in Pan'etaria offi-
cinalis (fig. 26) and the Hop ; in species
of Pilea they are linear or crescentic, and
suspended by the convex edge.

BiBL. Turpin, Ann. Sc. Xat. 2. vi. o ;
Dyer, Qu. Mic. Jn. 1872, 288 ; Quekett, Tr.
Mic. Sue. new ser. i. 20 ; Gulliver, Sei.
Gossij), 1873; Ann. N. H. 1865; Qu. Mic.

1869, 1873: M. M. Jn. x. 2-59,
xvui. 143 ; Lankester, Q. M. J. 1863, 243 ;
Urban, Bot. Zcit. 187.3, 266; Sanio, Monatsh.
Bed. Ak. 1857; Ilanslein, ihid. 18o9;
Holzner, F/o?-rt, 1864 ; Ililgers, Pringsheim's
Jahrh. vi. 1867 ; Rosanofi', Bot. Zeit. 1867 ;
Solms-Laubach, ib. 1874; Pfitzer, Flora,
1872 : Sachs, Bot. 66.

RAPIIIDIOPH'RYS, Archer.— A genus
of Rhizopoda.

Char. Bodies green, spherical, aggregate,
surrounded by a common investuient of
cloudy buff-coloured sarcode, containing
slender, hyaline, circular, siliceous spicula.
Pseudopodia arising from the sarcode
between the spicula, long, straight, and very
thin ; they never coalesce.

BiBL. Archer, Freslav. lihiz., Qu. Mic. Jn.
1869, 1871.

RAPHID'IU.V, Ktz.— A genus of Uni-
cellular Algae. Cells fusiform or cylindrical,
acuminate, straight or slightly curved, with.
green cell-contents. The species are those
of Ankistrodesmus, Closferiiim, Micrasterias,
and Scenedesmus of other authors.

Rabenhorst regards our C'losterium Griff.
(PI. 14. figs. 57, 58) as H. acicularc.

BiBL. Rabenht. Fl. Fur. Alg. iii. 44.

RAPHIG'NATHUS, Duges.— A genus
of Acarina, family Trombidina.

Char. Palpi long, with an indistinct
claw ; mandibles represented by two short
setae inserted upon a fleshy bulb, concealed
by a broad labium ; body entire : coxae
contiguous ; legs but little attenuated at the
ends, anterior longest, last joint longer than
the others.

It. rtiberrimus (PI. 6. fig. 35 a, labium with
mandibles and a palp ; h, a mandible).
Body oval, slightly depressed, smooth, and
almost free from hairs, rostrum forming a
conical process; eyes two, dark red, one on
each side at the anterior part of the body ;
labium triangular, concave ; setie accom-
panied by a more slender hair-like process ;
palpi large, inflated, clawof the 4th joint very
short. Found under stones and on plants.

R. hispidus. Form, that of the preceding ;
body velvety, with two posterior papillfe.

BiBL. Duges, Ann. Sc. Kat. 2. i. 22, ii,
55 ; Gervais, Walckenaer^s Apter. iii. 172 ;
Murray, Ee. Ent. 114.

RAT'TULUS, Lamarck.— A genus of
Rotatoria, of the family Ilydatinaja.

Char. Eyes two, frontal ; tail-like foot
simply styliform ; neither cirri nor fins pre-
sent. Teeth indistinct.

R. lunaris (PL 44. fig. 22). Eyes distant

REBOUILLIA.

[ 654 ]

REPTOMONAS.

from the anterior margin ; foot decurved,
lunate; freshwater; length 1-288".

BiBL, Ehrenberg, Infus. 448 ; Pritchard,
Infusoria, 088.

■REBOUIL'LIA, Raddi. — a genus of
Marchantieae (llepaticne), founded ou Mar-
chantia hemisphcrrica, Linn., characterized
by the conical or tlattened,l— 5-lobed stalked
receptacle ( fig. 610), the perigone being ad-
herent to the lobes of the receptacle on the
under side, opening by a slit (fig. 617) ;

Fig. 616.

Fig. 617.

Hebouillia hemisphsBrica.

Female recp]itacles, with the perigone burst.

Fig. 616, seen from above; Fig. 617, from below.

Magnified 2 diameters.

perichsete none, and the globose sporange
liursting irregularly. The antheridia are
imbedded in sessile, crescent-shaped disks.
The fronds are rigid, with a well-marked
midrib, green above, purple beneath. It
grows on moist banks, or by the side of
mountain-streams.

BiBL. Hook. Br. FI. ii. pt. 1. 108 ; Bis-
choff, JV^ova Acta, xvii. 1001, pi. 69. fig. 1 ;
Endlich. Gen. Plant. No. 408.

RECEPTACLES FOR SECRETIONS.
See Skceeting Organs of Plants.

RED SNOW.— The remarkable pheno-
menon Imown under this name has been the
subject of very extensive investigation, and
it is well known to be the result of the
enormous development of a microscopic
organism related to Protococciis or Chlami-
dococcus inridis. We are inclined to believe
that more than one 1'orra is comprehended
at present under the name of Protococciis or
Ilcematococcus nivalis ; for our specimens of
Arctic red snow, for which we were in-
debted to the kindness of R. Brown, appear
to belong to the same genus as Palmella
crucnta, as first indicated by Brown, and
confirmed by Sir W. Hooker. Greville's
figures of the Scotch plant closely resemble
this ; but the continental plants described by
Shuttleworth and others would seem conge-
ni>vic with Protococciis, Chlamidococcus, and
Chlamidomonas, since they produce active
zoospores, the forms which Shuttleworth

described as distinct Infusoria, as species of
Astada. Nearly connected with this con-
tinental snow-plant, if not identical, is the
Protococciis pi uvialiSjdLtiSiixihQ^ so elaborately
by Colin, which moreover appears to be
synonymous with the Uiscercea jmrpurea of
Morren.

The following is a description of the red
snow, brought home by Capt. Parry, from
our own observation. It may be noticed as
remarkable that, after being kept so many
years in a moist state in a stoppered bottle,
the structure appears almost unchanged, the
only difierence being the assumption of a
gieen colour on the surface of the masses
when exposed to light. Frond an indefinite
gelatinous mass densely filled with splierical
cells, about 1-200" in diameter (PI. 7. fig.
3f/) ; cells with a distinct membrane, their
contents consisting of numerous tolerably
equal granules, red or gi'een (see above).
Between the large cells lie patches of mi-
nute red granules (as in Palmella crnenta,
PI. 7. fig. 8 a, b), apparently dischai'ged from
the large ceUs. Bauer and Greville both
i describe this as the mode of propagation of
the plant ; but it is probable that the cells
also increase by division when actively ve-
getating.

BiBL. Brown, Appendi.v to Posses 1st
Voyage, 1819; DeCandolle, Bihl. miiv.
Geneve, 1824 : Hooker, Append, to Parry's
Second Voyaye ; Greville, Crypt. Fl. pi. 'I'-M ;
Shuttleworth, Bihl. univ. Geneve, 1840;
Morren, Mem. Acad. Bruxelles, xiv. 1841 :
PTotow, j\orrt Acta, xx. 11; Cohn, Nova
Acta, xxii. (305.

R1]NULI'N.\, Blake.— Minute subglo-
bular, hollow, calcareous bodies, l-:200" in
diameter, often silicified, entering largely
iuio the composition of the Coralline Oolite ;
regarded as probably organic by Sorby, and
referred to the Foraminifera by Blake.
(Sorbv, Qa. Geol. Jn. vii. 1851, 1 ; Blake,
Jn. Mic. Soc. 1876, 202.)

RENULI'TES, Lam. (Penulina, Blain-
ville). — A broad, reniform modification of
Vertebralina, one of the Porcellaneous Fora-
minifera.

IJiJiL. Carpenter, Infrod. For. 74.

RE'OPIIAX, Montlort.— A simple, uni-
serial subspeciesofZiYwo/a, straight or curved,
chahibers often angular or rugged in outline.
Abundant in manv seas. (Parker and
.Tones, Ann. N. II.\ vi. 340; Brady, Qu.
Mic. Jn. n. s. xix. 51.)

REPTOMONAS, Kt.— A genus of Rhizo-
Flagellate' Infusoria. Creeping ; fiagellum

RESERVOIRS.

[ 655 ]

RIIABDOSTYLA.

pinp-le, psoiidnpodia ftrising from the postcro-
veutral siirrace. R. cmuiata; in luvv-in fu-
sions, and decaying grass ; leiigtli 1-1000".
(Kent, /»/•. l>2;}.)

RESERVOIRS FOR SECRETIONS
IX Plants. See Skceeting Oiiuans of
riaiits.

RETE MUCOSUM. See Skin.

RETEP'ORA, Lamk.— A genus of In-
fundibulateClieilostomatous Polyzoa, family
Escharidai.

Char. Zoary leafy, reticular, fragile ; cells
ou one surface only, short, and not promi-
nent. Two l^ritisli species :

li. reticulata. Wavy and convolute, upper
side warty and very porous.

R. Beaniana. Umbilicate, funnel-sLaped,
wavy; interspaces unarmed.

BiBL. Jolmston, Br. Zvoph. 353 ; Gosse,
Mar. Zool. 18 ; Iliucks, Poli/zoa, 388.

RETICULA'RIA, Bull."— A genus of
Myxomycetes (Gasteromycetous Fungi)
characterized by the indeterminate, thin
simple peridium, bursting irregularly, with
the branched, shrubby, reticulated capilli-
tium adherent to it. Several species are
British ; they are rather large plants, grow-
ing over recently felled timber or on huUow
trees, rails, &c., with great rapidity.

BiBL. Berk. i?;-. Fl. ii. pt. 2. 308; Fries,
Sum. Vcq. 449 ; Syst. Mycol. iii. 83.

RETlCULA'PtlA, Carpenter.— Rhizo-
poda with long slender pseudopodia, which
meet and reticulate : as in Lieberkuehnia , and
other FoRAiiiNirEBA.

BiBL. Carpenter, Introd. For. 28; Micro-
scope, 47G.

RETINA. See Eye.

RHABUAM'MINA, Sars.— A relatively
large Arenaceous Foraminifer, usually tri-
radiate, but sometimes with ftair or even
five hollow rays or tubes, and sometimes
consisting of only the central chamber elon-
gated on two sides, forming one tube swollen
in the middle. R. abyssornm, Sars, At-
lantic and Pacific ; R. linearis, Brady, West
Indies and Soutli Atlantic, at great depths.
(Carpenter, Soiree, Mic. Sac. 1870, 5 ; Brady,
Jn. Mic. Sc. n. s. xix. 37.)

RHABDI'TIS, Bu]. See Anguillltla.

RHABDOGONIUM, Reuss.— A three-
or four-angled Orthocerine Foraminifer.

BiBL. Reuss, Sitz. Ah. Wien, xliv. 3(37.

RIIABDOLI'TH ES, Schmidt.— Minute,
subcylindrical, calcareous bodies, about
1-3000" length, usually consisting of a rod
and a terminal circlet of smaller rods
(1-25000"), simple or confluent. Abundant

with coccoliths in the mud of the Adriatic ;
and fossil with the same in tlie chalk of
Manitoba and Nebraska. Foimd also in the
t)cean-ooze by W. Thomson, and referred
by him to small floating spherules (possibly
vegetables) formed by their attached bases,
and termed by him Rhahdosphercs. (Schmidt,
Sitz. Ak. Wien, Ixii. (iOU, and Ann. iV. I£.
4. X. 309 ; Dawson, Canad. Nat. vii. 256 ;
W. Thomson, The Atthmtic, i. 221.)

RHABDONE'MA, Kiitz.— A genus of
Diatomaceas.

Char. Frustules tabular, depressed, com-
pound, fixed by a stalk arising from one of
the angles, with interrupted vittfe (front
view), vitta} capitate ; valves transversely
striate, strias extending into the front view,
and forming numerous longitudinal series.

Marine ; upon Algse. Striaj visible under
ordinary illumination ; the dark lines or
vittoe correspond to more or less complete
internal septa ; frustules connected with
each other by gelatinous cushions (isthmi).

Conjugation and the formation of sporan-
gia have been observed.

R. arcuatum i^Striatella arcuat., Ralfs)
(PI. 17. fig. 18). VittBe in two marginal
rows, isthmi convex. Length 1-.300''.

R.minutum (Tessella catena, Unlk). Vittae
in two marginal rows ; transverse strite faint .
Length 1-1200 to 1-9G0".

R. adriaticum. Vittse forming four rows
(interrupted in the middle, and again
between the middle and the margin on each
side) ; transverse striae distinct ; isthmi con-
cave. Length 1-480 to 1-170",

BiBL. Kiitzing, Bacill. 126, and Sp. Ahf.
115; Ralfs, Ann. N. H. xi. 455, and xii.
104 ; Smith, Diat. ii. .32 ; West, Micr. Jn.
1858, 186; Arnott, Micr. Jn. 1858, 91;
Rabenht. Alg. i. -305.

RHABDOPLEU'RA, Allraan.— A genus
of Polyzoa according to Allmau, and of
Hydroida according to Sars. Zoary tubular,
creeping or incrusting, septate, annulate,
bodies with an oral disk. It connects the
two classes, and presents many features of
great interest. Allman considers that its
polypary resembles that of the Graptolites.
Two species, on shells from deep water.

BiBL. Allman, Qu. M. Jn. 1874 ; Sars,
Qu. M. Jn. 1874, 23; Lnnkester, Qu. Mic.
Jn. 1874, 77; Hincks, Polyz. 577.

RHABDOSTY'LA, Kt.— A genus of
Peritrichous Infusoria. Solitary, like Torfi-
cclla, but with a rigid, short pedicle. Seven
species; salt or fresh water. (Kent, Inf

0t;4.) -^ ■

RHAGADOSTOMA.

[ 656 ]

RHIZOCLONIUM.

RIIAGADOS'TOMA, Koib.— A genus
of Micro-lichens parasitic on the thallus of
Solorina crocea. Spores 2-4, in lanceolate
fugacious thecne, large, simple, becoming 2-
locular, colourless. (Lindsay, Qu. Mic. Jn.
ISm, 344.)

RHAPIIIDOGL(E'A,Klitz.— Agenusof
Diatoniaceaj.

Char. Frustules navicular, arranged in
radiating crowded rows in a globose gelati-
nous mass. INlarine.

R. micans (PI. 19. fig. 11). Rows of frus-
tules irregular, obsolete ; valves linear-lan-
ceolate, subulate, somewhat acute. Length
1-140".

Three other species.

BiBL. Kiitzing, JJa^ill. 10 ; id. Sp. Ah/. 97.

RAl'IIIDOMONAS, Stein.— A geiius of
Flagellate Infusoria. Free, green, tlagellum
single ; mouth anterior, with a defined pha-
rynx ; an anterior row of trichocvsts. Ji.
se7ne7i = 3Ionas s., 'Ehvh.; length 1-500";
marsh-water, among decaying Sphagnum.
(Kent, Inf. ;191.)

RHAPHONE'IS, Ehr.— A genus of Dia-
tomacefe.

Char. Frustules single, quadrangular, na-
vicular ; valves without a median aperture
(nodule?) ; median sutural line longitudinal.
Marine. = Doryphora without a stalk.

Eleven species.

BiBL. Ehrenberg, Ber. Bcrl. Akad. 1844,
74 ; Kiitzing, Sp. Alq. 49.

RUIN OPS, Hudson.— A genus of Rota-
toria.

BiBL. Hudson, -4wi. Isai. Hist. January
1869.

RHINOT'RTCHUM, Oorda.— A genus of
Mucedines (Hyphomycetous Fungi), cha-
racterized by more or less clavate threads
studded with spicules, to which the spores
are attached. Several species occur in this
country. A very beautiful rose-coloured
species has lately' been gathered in rabbits'

dung.

Ncmatozomnn, Desm., difi'ers in bearing
necklaces of spores.

BiBL. Berk. Outl. 348; Cooke, Handb.
690.

RHIPIDODEN'DROX, Stein.— A genus
of Flagellate Infusoria. Bodies ovate, con-
tained in elongated parallel, granular tubes,
forming a branched zoarv. Two species;
freshwater. (Kent, Inf. 285.)

RIIIPIDOPIl'ORA*, Kiitz.— A genus of
Diatomaceas.

Char. Those of Licmop)1iora, except that
the frustules are each furnished with a

distinct stipes ; but as this is not always the
case, the character is of little or no value.
Marine.

Three British species (Smith) ; twelve
others (Kiitzing').

R. 2)arachxa^{V\. 17. fig. 19). Stipes fili-
form, dichotomous ; frustules in front view
broadly wedge-shaped, somewhat acute at
the base. Length of frustules 1-540 to
4-480".

RHIZAM'MINA, Brady.— A thread-hke
Foraminifer, or chitino-arenaceous branch-
ing tube (1-50" diam.), forming a tangled
weed-like tuft. R. al(/<Bformis, from 21(50
fathoms near Juan Fernandez. (Brady, Jn.
M. Soc. n. s. xix. 39.)

RHIZIDTUM, Braun.— A genus of Uni-
cellular Algae, allied to Chytridium. At
first unicellular, then bicellular, and with
delicate multipartite rootlets ; cells oblong ;
fructiferous cells beneath the apex; zoo-
spores with a cilium. Parasitic in Eughnce
and Nitclla.

BiBL. Braun, 3Ionatsh. 1856, 591 ; Ra-
benht. Ah/, iii. 284.

RIIIZ'iNA, Fr.— A genus of Helvelloidei
(Ascomycetous Fungi), distinguished from
Peziza by the bullate hymenium, con-
cave beneath, and furnished with rooting
fibrils.

Two species have been found in this
country, on sandy banks where the heath
has been burnt.

BiBL. Fr. Syst. Myc. ii. 33 ; Cui-rey, Linn.
Tr. xxiv. 493"; Cooke, Handb. 064.

RHIZOCLO'NIUM, Kiitz.— A genus of
Confervaceae (Confervoid Algae), distin-
guished by the decumbent habit and the
short, root-like appendages to the branches.

Kiitzing includes here many of our British
Conferv;© :

R. riinihirc, C. , Filaments simple, diam.
1-900", fine bright-green bundles 2 to 3 feet
long ; in streams and rivers ; common (l)ill-
wyn, pi. .39).

R. fortaosjim, Dillw. Filaments simple,
diam. 1-800", rigid, curled and twisted,
forming large strata; in salt-water pools;
abundant (Billwyn, pi. 46).

R. arennsmn, Carm. Filaments simple,
diam. 1-1000 to 1-1800"; in dirty-green
strata ; sandy sea-shores.

R. ohttmanyuliim, Lyngb. (PI. 9. fig. 12).
Filaments branched, diam. 1-1400"; pale-
green, stratified; sandy sea-shores.

R. 7-ipariu)n (Jergensii', Kiitz.). Fila-
ments branched, diam. 1-1400 to 1-1800",
Apparently not distinct from the preceding.

RfllZOGLYniUS.

[ 657 ]

KIIIZOSELENrA.

On sandy sea-fliores ; not uncommon (Engl.
Botany, pi. 2100).

R. implc.rmn, Dillw. Filaments simple,
diam. 1-2000"; bri^-ht preen ; forming large
strata, on mountain-rocks (Dill. C. iin-
ple.va, tab. B).

M. arenicolum, Berk. (Kochiamtm, Kz.).
Filament 1-2000 to 1-2400"; mountaiu-
rocks (Berkeley, Gleaninqs, pi. 13. fig. 8).

BiBL. liarvev, Mar. Alq. 200, pi. 24 F ;
Kutz. Sp. Alff. 385 ; Tab. 'Phyc. ; Br. Fl. ii.
pt. 1.354; Uillwyn,J?/-. Confervcs; Rabeulit.
Ah/, iii. 329.

KIIIZOG'LYPHUS. See Acartjs, p. 5.

RIIIZOMOU'PIIA.— The name given by
authors to certain mycelioid expansions with
a dark bark, which have been traced to
Polypori and Sphceriacei. Many of the
forms which occur in mines are remarkable
for their luminosity.

BiBL. Berk. Ini. Crifpt. Bot. p. 266.

RHIZONEMA, Thw.— A genus of Oscil-
latoriacese (Confervoid Algfe) =Z)ec/yo«p»i«,
Kiitz. This curious plant (It. inter nqituvi)
differs from its allies by the gelatinous
.sheath being composed of distinct cells and
furnished with branched root-like processes,
which anastomose freely. The cell-contents
are deep blue-green, with occasional yel-
lowish interstitial cells.

BiBL. Thwaites, Enq.Bot. Supp. pi. 2954;
Kiitz. Sp. Ah/. 321; Tab. Phyc. ii. pi. 40. f. 5.

RHIZOPHORA'CE^E.— A family of Di-
cotyledonous plants, to which belong the
celebrated Mangrove-trees of the tropics.
They are remarkable for the general occur-
rence of a ramified form of liber-ceU (PI. 48.
fig. 31). The long woody radicles pushed
out by the fruits, while still attached to the
parent tree, contain a vast number of these
ramified cells with very thick walls.

RHIZOPHYD'IUM, Schenk, = Chytri-
cliiim, sp.

RIIIZOP'ODA. Duj., or better, Psmdo-
poda, Ehr. — A Class of the animal subking-
dom Protozoa.

Char. Gelatinous, structureless aquatic
animals, mostly minute, locomotive organs
consisting of variable retractile root-like
processes — ^pseudopodia or false legs; no
mouth.

The food-particles are drawn into the
body by the pseudopodia, as described under
Actinophrys. The body is sometimes naked,
at others enclosed in a carapace or external
skeleton, which is either chitinous, calca-
reous, or siliceous. A nucleus and a con-
tractile vesicle are sometimes present, some-

times absent. In some, the protoplasm
contains granules and yellow cells ; these
have been supposed to be parasitic orga-
nisms, a rudimentary form of liver, or re-
productive organs. The presence of the
Contractile vesicle in some Uhizopoda, and
its absence in others, is entirely opposed to
the view of Stein and Kent, that the
presence of a contractile vesicle is a cha-
racter of animality ; unless many of the
Rhizopoda be referred to the Vegetable
Kingdom. The Class is divided into four
Orders, thus : —

Reticulaeia. Pseudopodia slender,
anastomosing to form meshes. — Foramiui-
fera, Lieberk'dhnia, Labyrinthula, &c.

Radiolaeta. Pseudopodia radiating. —
Actinophryina, Acanthometra, Polycystina,
Thakissicolla.

Lobosa. Pseudopodia short, A'ariable,
not anastomosing. — Amoebaja, Arcellina.

Gregarinida. Pseudopodia absent ;
these are often considered a distinct Class
of Protozoa.

BiBL. Dujardin, Ann. Sc, Kat. i., iii.,iv. ;
Schultze, Polythal., 1834; Carpenter, Phil.
Tr. 1856, 1859, 1862 ; Huxley, Invertebrata;
Williamson, Tr. Mic. Soc. 1852, 169, and ii.
159 ; Reichert, Ann. N. H. x. 1862, 401 ;
Kclliker, Zeitschr. wiss. Zool. 1849 ; Lie-
berkiihn, ibid. 1856, 808 ; Carter, Phizopoda
of Enq. Sf India, Ann. N. H. 1865 ; Tr. Mic.
Soc. 1849, 174 ; Mliller, Milll. Archiv, 1858 ;
Focke, Physiol. Stud. 1854; Fvesenius, Beitr.
z. mikr. Organ. 224; Miiller, Monatsb. Akad.
Berlin, 1856; Bailey, ^«?e/7C. Journ. Sci. xv.;
Claparede & Lachmanu, Infus. ; Haeckel,
Padiolarien, 1862; Gener. Morphol. ; Archer,
Qu. M. Jn. 1870-78; Hertwig & Lesser,
Arch. raih. An. 1874, x. Suppl. ; Schultze,
ibid. X., xi., xiii. ; Hertwig, Radiol. {Histol.)
1876 ; Wallich, M. M. Jn. xiii. 210 ; Ann.
N. IT. 1877, xix. 158 ; Claus, Zoologie; Leidy,
PWshw. Rhiz. N. Amer. 1879 ; Jn. 3Iic. Soc.
1880, 288; Butschli, Bronn's Klass. ^-c.
1880 {8f the Bibl. therein); Cienkowski,
Schultze's Archiv, 1876, xii. (tieio genera) ;
Pascoe, Zool. 1880, 6.

RHIZOPO'GON, Fries.— A genus of
Hypogfei (Gasteromycetous Fungi). R, ru-
bescens is found in sandy ground. (PL 27.
fig. 8, sporophores).

RHIZOSELE'NIA,- Ehr.— A doubtful
genus of Diatomacepe.

Char. Frustules elongate, subcylindrical,
marked with transverse or spiral lines, ends
oblique or conical, and with one or more
long terminal bristles ; marine and fossil.

2u

RIIODOMELA.

[ 658 ]

RHOICOSPHENIA.

Four i3iitisli species : R. styliformis, R. i
imhricata, li. setUjeray and R. (data. |

R. (data (PI. 51. lig. 25). R. americana \
(PI. 50. fifr. 46). 1

The British species were obtained from I
t'^alpa, Ascidia, and NoctUiica. {

BiBL. Ehr. Abh. Berl Ak. 1841, 291;
Kiitz. Sj). Ahj. 24; Bdghtwell, Micr. Jn. !
1858, 94.

RHODOM'ELA, Ag-.— A genus of Rho-
domelaceee (Eloiideous Algse), containing
two toleraljly common British species, with
feathery, inarticulate, branched fronds, the
branches composed of concentric layers of
oblong, colourless cells, with a cortical layer
of minute colom-ed cells. Colour of R. hjco-
podioides purplish brown, becoming black ;
height 4 to 18". Colour of R. snbfusca
brownish or reddish ; height 4 to 10". The
ceramidia are stalked on the ramuli, occur-
ring in summer ; the stivhidia, with tetra-
hedral tetraspores, occur in a similar situa-
tion in winter ; the antheridia (observed in
R. subfusca) also occur in tirfts in the same
position.

BiBL. Harvey, 3Iar. Aly. 78; Tiilasne,
Ann. Sc. Nat. 4. iii. 20.

miODOlMELA'CE^.— A family of Flo-
rideous Algae. Red or brown sea-weeds,
with a leafy or filiform, areolated or articu-
lated frond, composed of polygonal cells.
Fructification : 1. Conceptacles (eeraviidia)
external, ovate or urn-shaped, furnished
with a terminal pore, and containing a tuft
of pear-shaped spores ; 2. antheridia, borne
in tufts in similar situations ; 3. tetrasj>oret>
immersed in distorted ramuli or in lanceo-
late receptacles (sticJiidia), usually in rows.

Synojysis of the British Oenera.

Ochnthalia. Frond flattened, linear, ^\^th
an obsolete midrib, pinnatitid, alternately
inciso-dentate.

Rhodomela. Irond cylindrical, _ inarti-
culate, opaque. Tetraspores contained in
pod-like receptacles (stichidia).

Bostrychia. Frond cylindrical, inarticu-
late, dotted; the surface-cells quadrate,
Tetraspores in terminal pods.

Rhytiphlcca. Frond cylindrical, inarti-
culate, transversely striate. Tetrasj:ores in
pod-like receptacles.

Rolysi}>homa. Frond cylindrical, articu-
lated wholly or in part ; the branches longi-
tudinally streaked. Tetraspores in distorted
ramuli.

Dasya. Frond cylindrical, the stem inar-
ticulate ; the ramuh articulated, composed

of a single string of cells. 'Tetraspores in
pod-like receptacles (stichidia), borne by
the ramuli.

RHOBOSPOR'E.E:. See Algje.

RHODYME'NIA, Grev.— A genus of
Rhodj'meuificese (Florideous Algte), con-
taining seven British species, beautiful,
brightl3'--coloured sea- weeds, growing on
rocks or larger Algae, having a flat mem-
branous or somewhat leathery frond, ribless
and veinless, of parenchymatous texture.
{R. Rahnctta, PL 4. tig. 8'.) Most are not
more than 2" high, but R. laciniafa and
jjabncda gi'ow to 10" and 18". The coloiu'
is mostly rose- or blood-red. The coccidia
are formed on the lacerated margins or the
tips of lobes of the frond. The tetraspores
form cloudy spots along the margin, or are
scattered, tetrahedrally di\-ided. The an-
theridia likewise form patches on the sur-
face of the frond, in R. Palutetta and palmata.

BiBL. Harvey, Mar. Aly. 124, pi. 16 A;
Thuret, Ann. Sc. Xaf. 4. iii. p. 19, pi. 3.

RHODYMENIA'CE.F:.— A family of
Floiideous Algas. Purplish or blood-red
sea-weeds, Avith an expanded or iiliform
inarticulate frond, composed of polygonal
cells ; occasionally traversed by a librous
axis. Superficial cells minute, irregularly
packed, or rarely arranged in filamentous
sei'ies. Fracti/icafion: 1. Conceptacles (coc-
cidia), external or half-immersed, globose or
hemispherical, imperforate, containing be-
neath a thick envelope a mass of spores
affixed to a central column ; 2. antheridia,
collected in flat patches or sori ; 3. tetra-
spores, either dispersed through the whole
frond, or collected in indefinite cloudy
patches. British Genera :

•* Frond flat, expanded, leaf -like, dichoto-
mous or palmate.

Stenoqramme. Conceptacles linear, rib-
like.

Rhodyntenia. Conceptacles hemispherical,
scattered.

** Frond compressed or terete, linear or
filiform, much branched.

Sphcerococcus. Frond linear, compressed,
two-edged, distichously branched, with an
obscure midrib.

Gracilaria. Frond filiform, compressed,
or flat, irregularly branched ; the central
cells very large.

Ilypnea. Frond filiform, irregularly
branched, traversed bv a fibro-cellular axis.

RIK )I(!(,)SPnE'NL\,Grunow.— A genus
of Biatomaeea?, = arcuate Gomphoneina w ith

RHOIKONEIS.

[ 659 ]

EICCIA.

a central iiodulo in the curved side. R. cur-
vata (PI. ry2. iig-. 1')).

BiiiL. liabenht. Ahj. i. IVI.

RIIOIKONE'IS, Grim.— A subgenus of
Achnantludiiim, comprising two species^
found iu the Nortli Pacific.

BiBL. Rabouht. Alf/. i. 109.

RIIO PALOM Y 'CES,Corda.— A genus of
Mucedines (Ilypliomycetous Fungi), nearly
allied to AsPEiiaiLLrs, but having the

Fig. 618.

Fig. 619.

Rhopalomyces nigra.
Fig. 618. Tufts on wood. Nat. size.
Fig. 619. Fertile filaments. Magnified 200 diameters.

spores single (fig. 619), and not in monili-
form series. The single spores are borne j
on minute spines (fig. 619, left-hand head), i
They are mildews growing over decayed |
wood, matting, dung,"&c. Two new British
species are described by Berkeley and
Broome, found growing together.

BiBL. Berk, and Broome, Aidi. N. H. 2. \
vii. d'6, pi. 5.

RHOPALOSI'PHUM, Koch.— A genus ;
of Aphidte. Six species, on the currant and
goosebeiTV, Sonckm, Alisnia, Ligustrinn,
and JBerheris. (Buckton, Ajjhidce, Eai/ Sac.
ii. 9.)

RHUBARB.— Garden rhubarb (Meum
tindulafiaHfiind other species) afibrds, in the
large edible petioles, excellent specimens of
SpiRAX-tibrous Structures, spiral, an-
nular, and reticidate vessels and ducts : these
are readily isolated by the help of a needle
from a fragment of cooked rhubarb placed |
in water on a slide, and are well seen by
polarized light. The petioL.'S and leaves
I^Lkewise contain bundles of acicular Ra-
PHiDES. The roots also contain special
receptacles for a characteristic secretion.

RHYNCH.E'TA, Zenker.— A genus of
Acinetina. Body ovate, free or attached,
Avith a long anterior suctorial tentacle. Ii.
ci/clujnon, freshwater, on Ci/cloj)-". (Kent,
inf. 800,) 1

RHYNCHOL'OPHUS, Duges, = Eri/-
thrceus, Latreille (not Duges). A genus of
jV.raclmida, of the order iVcariua, and family
Trombidina.

C7uir. Palpi large, free ; labium penicil-
late ; mandibles ensiftn-m, very long; body
entire ; cox;e very remote, legs palp-like, i. e.
dilated at the end, posterior very long.

Species numerous ; foimd iu woods, under
leaves, and iu mosses.

Ii. citiereus (PL 6. fig. 40 : «, labium with
palp ; h, tarsus ; c, plume of labiimi more
magnified; d, mandible).

BiBL. D-iges, Ann. Sc. Nat. 2. i. 30;
Gervais, TVulokenaer's Aradodd. iii. 175 ;
'K.och, Deiitsclil. Crust.; ^Iwixiw, Econ. Ent.
124.

RIIYNCHONE'MA, Ktz.— A genus of
Zygnejiaceje (which see).

BiBL ; Rabenht. Akj. iii. 229.

RHYNCHOP'AGON, Werneck (Rota-
toria) =i)/(//e?ia with a bilobed roitrum !
Two species. (Werneck, Ber. L'crl. Ak.
1841, 377.)

RriYNCIIOP'ORA, = Lcin-alia pt. R.
hispinosa^i L. bisp.

RHYNCHO'PRION. See Pulex.

RHYTIS'MA, Fries.— A genus of Phaci-
diacei (Ascomycetous Fungi) , growing upon
the leaves of trees and shrubs, forming dark
patches or spots on the surface, breaking
through the epidermis with little scales or
irregular fissures. J?, acerinum is exceed-
ingly common, forming large black spots on
the leaves of the sycamore and maple; the
thecasporous fruit is perfected (on the di;ad
fallen lea\es j in spring ; Melasjua acerina,
which occurs in autumn, appears to be a
preparatory form of this plant. R. salici-
nuin is common on willow-leaves.

BiBL. Berk. Br. FI. ii. pt. 2. 290 ; Grev.
Crypt. Fl. pL 118; Fries, >S'i«wi. Vey. .'570;
Tulasne, Covipt. Rendus, 1852 {Ann. N. H.
2. viii. 118) ; Coruu, Comjd. Rend. 1878,
Grevilka, vii. 100.

RICASO'LIA.— A genus of Phyllodei
(Lichenaceous Lichens).

Char. Thallus lobate or laciuiate, affixed
by fasciculate rliizinte ; gouidia small , yellow-
green ; spores 1-3-septate. (Leighton, Brit.
Lkh. Flora, 112.)

RICCIA,L.— Agf-uus of Riccieaj (Ilepa-
ticte), consisting of minute green thalloid
productions growing upon damp ground or
tloating on water, distinguished from the
allied forms by the capsules being immersed
iu the sub.~tance of the frond, dc'stitute of
perichajte and perigoue, while the archegon(;

2u2

mccL\.

[ 660 ]

RIMULINA.

permanently encloses the sporange as an
adherent epigone, bearing a persistent stvle-
like neck (tigs. 621, 622). The antheridia

Fig. 620.

Eiccia fluitans.
lower surface of a frafrment of the frond, vrith three
imbedded sporanges projecting, their orifices being on
the upper surface.

Magnified 5 diajneters.

are globose sacs contained in special cavities,
the oritices of which, narrowed into a neck,
project as short processes from the surface
(cuspides). The epigone being adherent to
the sporange, the spores appear to lie im-
mediately in the cavity of the former when

Fig. 621.

Fig. 622.

Eiccia fluitans.

Fig. 621. Vertical section through the frond and spo-
range contained in its svib.^tance.

Fig. 622. Sporange, with persistent epigone, extracted
from the frond.

Magnified 25 diameters.

ripe ; they are unaccompanied by elaters, and
escape by irregular rupture of the epigone.
Several species occiu- in Britam.

* Terrestrial.

a. (jiauca, L. Frond without membran-
ous .scales below, fleshy, ovate-oblong, two-
to three-lobed, 1-2 to 1" in diameter, the
divisions dichotomous, growing in orbicular
tufts, surface smoothish, punctate, glaucous
green. On banks.

II. crystaUimi, L. Differing from the
last chieily in lai'ger size and lighter colour,
and having large cavernous air-cells opening
Avidely on the upper siu-face. Damp mould.

** Aqttatic.
11. fluitans, L. (fig. 620). Fronds with-

out scales below, 1-2 to 2" long, repeatedly
forked, segments linear, notched at the
ends ; when placed on damp earth it pro-
duces radical hairs, (fig. 621-2). Stagnant
water.

It. natans, L. Fronds with long reticu-
lated scales below, obcordate, 1-2" long, or
with the two lobes again divided ; scales
of the lower surface pm-ple. On stagnant
pools.

BrBL. Hook. Br. Fl. ii. pt. 1. 102 ; Bis-
chofl". Nova Ada, xvii. 909 ; Lindenberg,
ibid, xviii. 361 ; Hofmeister, Vergl. Unters.
43 ; Knv, Jahrb. wiss. Bot. v. ; Tr. Mic. Soc.
1880, iii'. 125.

RICCIE'^.— A tribe of Liverworts or
Hepaticae, consisting of delicate, green,
membranous fronds, spreading on the ground
or floating on water. The fruits are always
sessile on the frond, more or less imbedded
in its substance according to the thickness ;
the spores are unaccompanied by elaters.

Synojjsis of British Genera.

Sj)Iicei-oca>-pus. Archegones dorsal, on a
lobed membranous frond, sparingly aggre-
gated. Perichsete obtusely conical or pear-
shaped ; perforated at the summit, con-
tinuous with the frond. Perigone wanting.
Epigone crowned by the deciduous style.
Sporange at length free, indehiscent.

Biccia. Archegones immersed in the
frond, scattered, neither emergent nor ex-
posed on the surface imtil burst. Perichajte
and perigone lindistinguishable. Epigone
crowned by the enlarged, long, persistent
style, adherent to the sporange. Sporange
bursting iiTegidarly.

RICE. — This grain is produced by the
grass called Oryza sativa. The seed is
remarkable for the hard character of the
albumen, which is explained at once when
we examine a section under the microscope
(PI. 46. figs. 12 & 13). The ceUs are filled
with very small starch-grains, which are
packed so closely that they assume a paren-
chymatous form and present the appearance
of a continuous tissue (as in maize). The
cohesion of the starch-gi-anules is the cause
of the peculiar grittiness of rice-flom". See
Staech.

PJMULA'PJA, Nyl.— A genus of Leci-
deinei (Lichenaceous Lichens).

Char. Apothecia black, rounded, de-
pressed in the centre, dehiscing by a sub-
radiate fissure ; spores simple. (Leighton,
Lich. Flora. 438.)

RLMULI'NA, D'Orb. — A Nodosaiine

RIND.

[ CGI ]

ROCKS.

Foramiuifer, with oblique chambers, anil a
long sHt-like oritice ou the edge of the last
chamber. Aclriatic. (Parker, J. & B.,
Ann. N. 11. 8. xvi. 1-).)

RIXD.— This word is used to denote _a
structure intermediate between epidennis
and bark, — a compound structure consisting
of several, or many layers of cells and even
of distinct forms of tissue, but not present-
ing the characteristic kinds and arrange-
ment which occur in true Bark.

KIVULA'RIA, Koth.— A genus of Oscil-
latoriaceie (Confervoid Algae), subdivided
by Kiitzing, and restricted to the forms in
which there is a distinct manubrmm or
elongated cell next to the globular basal
cell. As thus defined, it contains only a
few aquatic species, the rest being trans-
ferred to Physactis, Euactis and allied
genera.

R. anffidosa, Roth. Frond floating, glo-
bose, dirty-green ; manubria oblong and
curved, or oblong-ovate and abbreviated ;
filaments torulose at the base, interruptedly
articulated at the apex. E/iff. Bot. 968.

R. Bonjana, Kg. (PI. 6. tig. 18)_. Frond
globose, greenish brown ; the size of a
cherry ; manubria large ; sheaths veutricose,
colourless, with plaited constrictions ; fila-
ments moniliform or interruptedly articu-
late, flagelliform. ^.Jiaccida, smaller, fila-
ments flaccid, not interrupted. Doubtful
species : R. hoinjokles, and R. plana.

R.plicata, Harv. Frond densely grega-
rious, compresso-pUcate, often hollow and
ruptured, dark green : filaments spuriously
dichotomous, attenuated.

BiBL. Kiitzing, Sp. Alg. 336 ; Tab. Fliyc.
ii. pis. G7, 68 ; Harvey, Br. Alq. 1 ed. 150 ;
Hassall, Alg. 262, pi. 64 ; Eng. Bot. Swpp.
pi. 2911.

ROBERTI'NA, D'Orb.— A modification
of the Bulimine form of Foraminifera with
long oblique chambers, 7-10 in the last
whorl, and interdigitating : orifice comma-
shaped. Recent and fossil.

BiBL. Carpenter, For. 196 ; Parker and
Jones, Phil. Tr. civ. 375.

ROBERTSO'NIA, Br. — A genus of
Copepodous Entomostraca. R. tenuis, in
dredgings. (Brady, Copepod., Ray Soc. ii.
25.)

ROBULI'NA, D'Orb.— A common form
of Cristellaria, in which the orifice is trian-
gular.

BiBL. Williamson, Rec. For. 24 {Cris-
tellaria) ; Parker and Jones, Ann. N. H. 2.
xix. 289.

ROCCEL'LA, Ach.— A genus of Rama-
lodei (Lichenacet)us Lichens)), growing on
marine rocks, remarkable as furnishing tho
dye called orchil or archil. R. tinctoria,
phycopsis, and fusiformis, the British spe-
cies, grow only in the extreme south of
England.

BiBL. Hook. Br. Ft. ii. pt. 1. 225; Engl.
Bot. pis. 211, 728; Leighton, Lich. Fl.
73.

ROCKS. — Rocks are roughly divided,
according to their origin, into an eruptive
and a sedimentary series. Again, the erup-
tive rocks may be classed in two great
groups, the vitreous and the crystalline ;
the former being in great part structureless,
while the latter consist essentially of cry-
stals. A microscopic examination of the
vitreous rocks, such as Obsidian, pitchstone,
pearlite ifcc, shows, however, that rocks of
this class are not wholly devoid of structure,
since they almost invariably contain large
numbers of minute crystals (microliihs) too
small to be referred with certainty to
any known mineral species, together with
more or less sparsely disseminated crystals
of lai'ger size. The microliths, moreover,
are frequently disposed in approximately
parallel and often tortuous bauds ; while
sometimes, bauds of structureless matter,
glass of a slightly ditferent colom* and den-
sity, are seen to traverse the rock. These
bauds, as shown in PI. 42. fig. 8, whether
consisting only of glass, or whether I'e pre-
sented by lines of microliths, are very cha-
racteristic of lava-streams, and are indica-
tive of their fusion and flow. Such struc-
tures are not always apparent to the naked
eye ; and in these cases the microscope -often
serves to demonstrate the conditions under
which certain rocks have been formed.

In the examination of the crystalline
rocks, which are essentially built up of
crystals, frequently of difterent minerals,
and pertaining to various crystallographic
systems, it becomes necessary to determine
their optical characters; and for this pur-
pose the employment of polarized light
affords the best means of discriminating be-
tween them; since, in thin sections of
fine-oTained rocks, the application of re-
agents to any particular crj-stal or grain is
a matter of some difiiculty. Before enter-
ing, however, upon the subject of the cry-
stalline rocks, it may be well to take a
glance at a few of the most characteristic
features presented by the vitreous series.

In the Obsidians, pitchstones, pearlites

ROCKS.

[ 662 ]

ROCKS.

find taehyh'te?, uiioroliths and other minute
-truftnres are almost always present. Some
of tliese are mere opaque hairs or threads,
called trichites, stranguly beut and twisted
(PI. 42. fig. 8), aud concerning whose
niineralogical character nothing definite is
kno-wn. Others are fine needles, sometimes
•with lateral growths, which, as in the
pitchstone of Corriegills in AiTan (PI. 42.
fig. 5), resemble, when highly magnified,
the fronds of ferns. These spicular bodies
or belonites have been referred to angite.
In many of the obsidians and pearlites, the
microliths are minnte elongated prisms or
cylinders, and their ends often appear to
be rounded. They commonly form dense
streams, their longest axes lying in approxi-
mately uniform directions, except where
larger crystals occur; and at these points
the streams ai'e deflected and appear to
sweep round the obstacles. In some of the
obsidians and vitreous basalt-lavas, the crj'-
stallites exhibit a more or less complex
structure, as in PI. 42. fig. 4, the relation
of which can occasionally be traced to per-
fectly developed crystals. In the pearlites
and in some other glassy rocks, curious
little cracks occur, which separate the rock
into minute spheroids (PI. 42. fig. 7).
The cracks are seldom continuous all round
the form, but thin away in a very cha-
racteristic manner. There is no nucleus,
and the phenomenon appears to be solely
due to shrinkage upon cooUng. The streams
of microliths which often traverse these
roclfs, pass without interruption through
this pearlitic structure.

Spherules are sometimes plentifully deve-
loped in A^itreous rocks, and result in many
cases from ciystallization around a point or
along a line (axiolites) of limited extent.
PI. 42. fig. 6 shows parts of two spherules,
in an obsidian from the Lipari Isles, which
have partially coalesced ; and in some speci-
mens they ma}' be found united in con-
tinuous strings.

In the felspars and other minerals occur-
ring in certain lavas, enclosures of vitreous
matter are sometimes visible. These are
small portions of the glassy magma which
have been entrapped by the crystals during
their formation. PI. 42. fig. 2 shows glass
lacunae of this kind enclosed within a fel-
spar crystal in one of the lavas of Etna,

The crystalline eruptive rocks consist, ns
already stated, of crystals or crystalline
grains of various minerals, and it is neces-
sary to study their optical characters in

order to determine them with any preci-
sion. Before entering, however, upon this
method of investigation the student should
become familiar with ordinaiy hand speci-
mens of the chief rock-ft)rming minerals,
and should acquire some knowledge of the
simple tests, both physical and chemical,
which distinguish the different species. In
the absence of such elementai-y knowledge,
deductions based solely upon microscopic
observations are sure to be untrustworthy,
if not worthless. The text-books from
which this rudimentary instruction may be
derived are too numerous to need mention.
For the study of the optical properties of
minerals the student may advantageously
consult the works of Dana, Zirkel, Rosen-
busch, von Lasaulx, Fouque, Levy, and
other recent contributors to microscopic
petrography.

In a mei'e sketch of the subject, such as
this must necessarily be, it is impossible to
do more than allude to the microscopic
characters of a few of the most typical
rocks ; and in doing so, we may begin with
a thin slice of gi-anite (PI. 42. fig. 9). The
student doubtless kmows beforehand that
he is dealing with a rock composed essen-
tially, of felspar, mica, and quartz. But
there may be more than one species of fel-
spar present, and the mica may also be of
various kinds. To determine the character
of the felspars, he must study their angles
of extraction between accurately crossed
Nicol's pri,sms ; and to do this, it is neces-
sary to employ a microscope with a pro-
perly di-\ided, rotating stage, which can be
centred correctly for any object-glass which
may be used, so that a minute speck in the
preparation can be made to revolve imme-
diately beneath the point of intersection of
tv.o crossed spider-lines set within the eye-
piece. He can, in most cases, ascertain
I whether the felspars crystallize in the
monoclinic or in the triclinic system by ob-
serving the character of the twinning in
polarized light. The nronoclinic felspars
are usually twinned on what is known as
the Carlsbad type, and show only two dif-
ferently coloured halves or lamellae ; while
the triclinic felspars are striated by nume-
rou.s twin-lamella?, which polarize in dif-
ferent alternating colours; unless, of cour.se,
in either case, the plane of section coincides
with the plane of composition of the twin-
lamellae, /. e. the direction in which the
plates appear to be stuck together. In the
moni^clinic felspars, the maximum extiuc-

ROCKS.

[ "'<'-i ]

ROCKS.

tioii between crossed Nicols either coincides
with the edge formed by the union of the
basal plane and the clinopinakoid, or else
lies at rio-ht angles to this edge ; while
in the triclinic system the maximum extinc-
tion does not coincide with, or stand
at riglit angles to the homologous edge
formed by the basal plane and the brachy-
pinakoid, but occurs in some azimuth on
one or the other side of those directions,
the angle being determined by rotating the
stage upon which the preparation lies. To
facilitate the recognition of the precise
azimutli in which the axes of elasticity lie,
an axially-cut plate of quartz, having a
thickness of 1-G", is inserted between the
object-glass and the analyzer, and the
Nicols should be so adjusted that a uni-
formly violet light pervades the field. A
known crystallographic edge being made to
coincide with one of the spider-lines, the
section is then turned, imtil a tint is esta-
blished which exactly corresponds vritli the
tint visible in the field of the microscope
wlien the preparation is removed. Similar
determinations may also be effected by
stauroscopic methods, which are described
in the worlvs already cited. Tliese means
of ascertaining the position of the axes of
elasticity, are of course applicable to anj^
minerals which are translucent when cut in
sufficiently thin slices. Tables of the angles
of extinction in the different minerals will
be found in various works on mineralogy.

Reverting to our section of granite, we
may notice that there is perhaps more than
one kind of mica present. One is probably
of a more or less deep-brown colour, and
the plane of the section may be either
parallel with the basal planes of the cry-
stals, thus affording six-sided forms, or it
may cut through the crystals at some angle
to the basal plane. In the latter case it
will be found, that by rapidly rotating the
polarizing prism, the analyzer being re-
moved, a marked change of colour or tint
occurs, while, if the mica be colourless,
there wiU merely be a slight change in the
intensity of the light transmitted under
similar conditions. The brown, or in hand
specimens often black, mica is commonly
Biotite, the colourless mica, Muscovite ;
but there are many other species of mica,
and in order to know which species is pre-
sent, it may be needful to have recourse to
blowpipe analysis or to an examination of
cleavage plates, or of sections coincident
with the basal plane, in convergent pola-

rized hght. For this purpose twn or nion-
strongly converging lenses are placed above
the polarizer, and are brouglit just benoath
the preparation. A wide-angle half- or
quavter-mch object-glass should be used in
conjunction with an eyepiece-fitting ■with-
out lenses, surmounted by an analyzer ; or
better, the arrangement introduced by
Swift, of University Street, Tottenham
Court Road ; in either case, the Nicols being
accurately crossed. To determine the posi-
tive or negative character of the crystal, a
quarter-undulation plate, or a quartz-wedge,
should be employed; but the manner of
using it and the phenomena observed under
these conditions must be looked for in
books specially devoted to such questions.
Again, in a thin section of granite, the
observer will also notice the presence of
more or less quartz. Tliis will appear
coloiu'less and limpid bv ordinary trans-
mitted illumination, but in plane-polarized
light it will exhibit strong colours ; and in
convergent light it will, if of suitable thick-
ness, show a more or less perfect inter-
ference-cross. The rotatory polarization of
quartz cannot be observed in ordinary
microscopic rock-sections, which are far
too thin to permit this phenomenon.

Quartz, when examined under moderately
high powers, is usually seen to contain
lacunaj partially or wholly filled with fluid,
which is very commonly, but not always,
water. In the partially filled cavities,
bubbles of course exist, the size of which in
relation to the size of their containing cavi-
ties represents the condensation which the
liquid has rmdergone since its imprison-
ment. On the application of heat the
bubbles contract. The cavities vary greatly
in form ; those shown in PL 42. fig. 1 are
imusually large. The bubbles in these lacunae
sometimes exhibit spontaneous motion when
high powers are emploj'ed.

PI. 42. fig 10. represents part of a section
of Syenite. In this rock, hornblende is
one of the essential constituents. In one of
the patches of hornblende there figured, the
characteristic cleavages are shown, inter-
secting at an angle of about 125°. These
cleavage-planes run parallel with the faces
of the oblique rhoanbic prism. In augite,
the corres~ponding cleavage-planes intersect
approximately at right angles. Hornblende
may also usually be distinguished from
augite by its dichroism, which becomes
evident when the lower Nicol is rotated, the
analyzer being removed. Augite shows, as

EOCKS.

[ GC4 ]

EOCKS.

a rule, no dichroism. Augite is a common
constituent of Basalt and other rocks of a
basic cliaracter. Fig. 18 shows a section of
a crystal of augite cut transversely to the
principal axis. Li fig. 14 are shown the
very peculiar forms of hornblende, which
occur in some phonolites, and which from
their frayed-out ends can sometimes hardly
be recognized as crystals. In fig. 15 some
more hornblende is shown, occurring in a
dioi ite ; the character of the twinning in the
triclinic felspar is shown in this drawing.
It is in the nature of the felspar that diorite
differs from syenite. The original syenite
of Pliny, from Syene in Egypt, contains
quartz. Many petrologists, however, now
exclude from syenite those rocks in which
quartz is present. The quartzless syenites
are closely related to minette (PI. 42. kg. 11) ,
in which magnesian mica takes the place of
hornblende. The crystals of mica constitute
the chief features of the rock. The matrix
in which they lie is a finely crystalline mix-
ture of felspar and mica. In the drawing,
the central crystal of mica is cut trans-
versely to the basal plane : the line stri;e
representing the direction of cleavage or the
characteristic platy structure of mica. A
crystal of magnetite is also shown in this
drawing. It is a section through an octo-
hedron. Among the minerals which crys-
tallize in the cubic system, Haiiyne and
Noseaii are often met with in volcanic rocks.
In PI. 42. fig. 14 some crystals of Noseau
are shown ; like all cubic minerals, they
exert no influence upon polarized light.
Haiiyne and Noseau exhibit structiu'al pecu-
liarities when examined under high powers,
which cannot be described or figured in this
short article. Fig. 16 represents a crystal
of Olivine in a Saxon basalt. Olivine is
a common constituent of basalt, and some
modern petrographers exclude from basalt
any rock from which olivine is absent : thus
many of the rocks which in England have
always been regarded as basalts, would
under this new arrangement be classed with
the andesites. Olivine being a rhombic
mineral, has its axes of elasticity coincident
with its crystallographic axes. Fig. 17
represents a section of basalt from the
Giant's Causeway, as seen by polarized
light under an amphfication of 77 diameters.
The black patch in this drawang indicates
magnetite or titaniferuus iron, both of which
minerals are commonly more or less plen-
tiful constituents of basalt. PI. 42. tig. 15
shows a transverse section of a crystal of

Nepheline partly filled with dusty matter.
Nepheline is sometimes met with in bascilts ;
this drawing is made from a phouolite. The
phonolites are rocks which essentially con-
tain nepheline. The green crystals in the
drawing are microliths of hornblende.

The rocks Diabase and Gabbro may be
regarded as varieties or special conditions
of basalt. The latter rock contains diallage
instead of augite ; but these two mineral
species ai-e now regarded by some mineralo-
gists as identical.

The rocks termed Norite and Hj'persthe-
nite, contain the rhombic forms of pyroxene,
hyjiersthene, and enstatite. Fig. lu is
drawn from a section of trachyte and shows
crystals of sanidine and oligoclase,the former
a monoclinic, the latter a triclinic felspai-.
In the centre is a crystal of sphene or
titanite, which although not a very common
rock-forming mineral, nevertheless occurs
both in plutonic and volcanic rocks.

We now come to rocks of a diti'erent class
to those just described. These are kuo-svn
as jnetamorpJuc ; and they are regarded by
some as the result of the alteration of sedi-
mentary rocks by high temperatures existing
at great depths beneath the surface of the
earth, or by the contact or proximitj' of
eruptive rocks. Others regard them in
many cases as the residt of crystallization
from solution, and not by fusion, set up in
sedimentary rocks subsequent to their depo-
sition. Whatever may have been the pro-
cesses by wdiich they have arrived at their
present condition, we find that they consist
of minerals which, in the main, are identical
with those which are met with in eruptive
rocks : thus, gneiss for example, is ideutic-al
with granite so far as its mineralogical con-
stitution is concerned ; but the crystals and
crystalline grains which compose the rock,
are arranged in more or less definite layers
of different mineral character, an arrange-
ment termed foliation. Mica-schist (PI. 42.
fig. 20) is another example of a metamor-
phic rock, and consists essentially of rudely
alternating layers or films of mica and
quartz. Chlorite-, talc-, schorl-, and horn-
blende-schists are rocks of similar structure,
and contain respectively the minerals which
their, names imply, together with quartz,
and at times felspars, garnets, &c., while
staurolite, chiastolite, kc. are met with in
certain argillaceous rocks which have also
been subjected to alteration. Quartzite
again is an .altered sandstone, and the bed-
ded hjillefiiutas of Scandinavia (PI. 42.

ROC lis.

[ 665 ]

ROCKS.

fig. 12) are usually regarded as altered
fel;<patliic .saiidstoues, which are identical in
miuural cous^tilu'iou aud structure with
the rocks liuowu as t'elstoue, wliich coosist
of a luicro-crystaUine admixture of felspar
and quartz, and in which the boundaries of
the component grains are uot always clearly
defined under the microscope. This hazy
ill-detined granular structure is spoken of
as a crypto-crystalliue one ; while there is
ako another condition of matter having the
same chemical composition in which merely a
nebidous, granidar, or faintly-marked tibrous
structm-e distinguishes it from vitreous sub-
stances, its optical character being similar
to that of glass. This is known as micro-
felsitic matter.

The four drawings which constitute the
lower row in Plate 42 represent sedimentary
rocks, or those which have resulted from
the disintegration of preexisting laud, the
degi-aded ruaterials having been transported
by rivers aud deposited in the sea or in lakes.
Sandstones, shales and slates, and lime-
stones, may be regarded as the principal
t^pes of these sedimentary deposits. PI. 42.
fig. 21 represents a section of millstone grit
as seen under polarized light. The rock
consists essentially of fragments of quartz
with some fragments of felspar, bound to-
gether by a ferruginous cement. The frag-
ments have probably resulted from the
disintegi-ation of granitic rocks, the mica,
owing to its form rather than its specific
gravity, having been held longer in suspen-
sion, and transported to greater distances in
the old seas in which these materials were
deposited. PI. 42. fig. 22 represents a piece
of Cambrian slate from the Penrhyn quar-
ries in N. AVales. The appearance is that
presented between crossed Nicols. The
general elongation of the constituent particles
in the direction of cleavage, is the result of
pressure, which is further demonstrated by
the frequent distortion of the fossils met
with in these old deposits. Microliths are
also present whicb have been developed
subsequently to the deposition of the rock.
Similar microliths in other Palaeozoic slates
have been referred by Kalkowsky to anda-
lu,~ite, a silicate of alumina. PL 42. fig. 2-3
shows the small spheroidal grains which
occur in the Great Oolite of Lincolnshire.
They are concentric deposits of carbonate of
lime, which often, as in the largest spheroid
in the figure, have a foraminifer as a
nucleus ; in some cases the accretions have
taken place aroui.d a grain of sand. The

interstitial matter in these rocks is usually
crystalline carbonate of lime. PI. 42.
fi;,'. 24 is an example of a crystalline, sac-
charoid limestone, statuary marble. It
consists wholly of crystalline grains of
calcite. The twinning of the separate crys-
tals, parallel to a rhombohedral face, i3
reju-esented as it is seen by polarized light.
It is impossible in this article to cite
further examples. Volcanic ejectamenta,
which both in their loose and consolidated
states, oiler problems of great interest to the
geologist, must pass unnoticed ; but, before
closing this article, it may be worth while
to make a few remarks on the relative
merits of thick and thin microscopic sections
of rocks. In the first place thick sections
are easier to prepare ; but in most cases
they are of little or no use to the student,
since the optical properties of the different
minerals cannot as a rule be properly
studied from such feebly translucent pre-
parations. The rotatory polarization of
quartz cau of course only be observed in
thick sections taken at right angles to the
optical axis ; and dichroism, when barely
perceptible in certain thin slices, becomes
well marked in thicker ones; but apart
from these advantages which thick sections
possess, they have others. A thick un-
mounted section can be submitted to the
action of chemical reagents, and in many
cases may be subsequently washed, ground
thinner, and finally mounted, while much
useful information may be thus gained.
Little objection can also be raised to thick
sections of vitreous rocks, when they happen
to be very transparent, since the crystals
which theycontain may then be studied in
their integrity ; whereas in thinner sections
we can merely examine slices of them.
Furthermore, in the preparation of very thin
sections there is always the danger either
of stripping out the larger crystals, or of
ultimately wasting labour by grinding away
the whole of tlie preparation. Thick sec-
tions are best examined by reflected light,
when many important points are often dis-
cerned,_ which would never be noticed if
transmitted fight only were employed. As
a rule, however, it is scarcely possible to
prepare too thin a_ section of a rock, nor to
over-estimate the value of the thinnest pre-
parations which can be procured; since a
few finishing touches may often permit the
recognition of structure which would other-
wise pass unnoticed. Most of the lapi-
daries in this country spoil their sections

ROOKS.

[ 666 ]

ROOTS.

through uot risldnp: tlieir loss or diminutiou

bv those

finisliing

strokes which

of size

render a, preparation useful or -worthless.
The best sections I have yet seen are those
prepared by Ciittel, of New Compton Street,
Soho. Good rock-sections may also be pro-
cured on the continent, notably from Yoigt
and Hochgesang of Vienna, Marchand
of Paris, and Fuess of Berlin. Machines
for the preparation of roelc-sections are
made by Cotton and Johnson of Grafton
Street, Soho, Fuess of BerHn, and others.
Mucli may, however, be done simply with a
flat cast-iron plate and emery, while a file and
hone will suffice for the preparation of some
of the softer rocks. Chapters on this
branch of microscopical work wiU be found
in ' The Study of Rocks,' and in Beale's
* How &c.' Microscopes suitable for this
branch of study, are made by Watson, of
4 Pall Mall, and Swift, of University Street,
Tottenham Court Road.

The student of petrology should, how-
ever, study the great features presented by
rock-masses, and learn to recognize the
large crystals, with which Nature and the
mineral-dealer can provide him, before he
commits himself to microscopic investi-
gation.

BiBL. Zirkel, Mtkr. Beschaff. d. Mine-
ralien und Gesteine, 1873 ; id. Mikr. Zitsam-
mensetzwng d. BascdUjesteine, 1870 ; id.
Microscopical Petrography, U. S. Oeoloy.
Explor. ofthe¥)th pnrollel, 1876; Vogel-
sang, Die KrystaUiten, 1875 ; Rosenbusch,
Mikrosliop. I'hysiograpliie, 1877 (coloured
plates), and the Bihl. ; Mohl, Basalte mid
Phonolithe Sdchsens, 1873; Poussin and
Renard, Caract. mineral. S^'c. des roches Plu-
tonnienyics de la Belyique ct de TArdenne
Frangaise, 187G ; Boiicky, Petrograph.
Stud. Basaltgesteinen Bohmens, 1874 ; id.
PJionolifJigesteine Bohmens, 1873; id. Me-
laphyrgest. 1870; id. Elemeide c/icin.-mi-
krosk. Mineral- und Gesteinanalyse, 1877 ;
(the last 4 works are in the Archiv d. Na-
turtvissenschaftl. Landosdtirchforschung v.
Bohinrn); Credner, Pefrograj>Jii-tc/ie Geologic
{Element e d. Geologic., 1870) ; Lasaulx,
Pctrographie, 1875 ; Geikie, Carboniferous
Volcanic Rocks of the Basin of the Firth of
Forth, Tr. R. Soc. Ed. 1879 ; FouqutI an'd
Levy, Mineralogie Micrographique, Roches
eruptives Fram^., coloured plates and Bibl.,
1879; Sorby, Anniversary Addresses to Geol.
Soc. Land., 1878-70; Rutlev, The Study
of Rocks, 1879; Geikie, Text-Book, 1882.

Numerous papers on Microscopic Mine-

ralogy and Petrology, by Phillips, Sorby,
Allport, Bonney, Ward," Davis, Daintree,
and others, will be found in the Qu, Jn.
Geol. Soc, others in the Jn. Mic. Soc, Tr.
Roy. Soc. Ed., the R. Irish Academy, the
Roy. Irish Geol. Soc, Xeues Jahrh. f.
Mineral., Zeitsch. d. deutsch. geol. Gesellsch.,
Bull. d. I. Soc Mineral, d. France, &c.

RCESTE'LIA, Rebent.— A genus of Ure-
dinei (Coniumycetous Fungi), closely re-
lated to iEciDiuji, and presenting sfmilar
spermogonia and perithecia ; the chains of
spores of the Rastelice, however, present a
peculiarity, — having a sterile joint, forming
an isthmus of variable length, between
each spore : the peridium bursts irregularly ;
or (in R. cancellata) the teeth cohere more
or less for a time, so as to form a kind of
lattice. Tliis genus includes ^cidium cor-
nutmn, laceratum, and cancellatum of older
authors, growing respectively on the leaves
of the moimtain-ash, hawthorn, and pear.
See y^EciDiuM and Uuedikei.

ROOTS. — The structure of roots presents
important modifications ; but these are less
striking than those in stems. In all cases
they have a fibro-vascular axis enveloped in
a more or less thick cortical parenchyma,
covered when yoimg by a delicate epidermis
devoid of stomata (epiblema), when old by
an epidermal tissue of corky nature.

The roots of the vascidar Cryptogamia
are all adventitious ; and their structure
consists merely gf a central fibro-vascuLir
axis, surrounded by a cellular cortex and an
epidermis provided with root-hairs of a
yellowish colom'.

Dicotyledons produce an axial root, which
is a direct prolongation of the stem down-
wards ; and both this and the adventitious
roots frequently developed on the stem have
the peculiar imlimited fibro-vascular struc-
ture found in the stems of this class, and
may become woody and increase by annual
layers lilce the ascending axis. The axial
root of Dicotyledons, being a direct con-
tinuation of the stem, displays a circular
group of fibro-vascular bundles as in the
ascending axis : but these mostly converge
at the point of junction of .stem and root
(collar), so tliat tlie central axis of the pa-
renchyma, the pith, is lisualty absent, the
medullary rays remaining as in the stem.
Externally, uirain, there is a difference, since
the liber-bundles vanish and the cambium-
region passes at once into the cortical pa-
renchyma,' here colourless and succulent,
and tliis is clothed by a less prominent peri-

ROOTS.

[ 667 ]

ROOTS,

derm tlian the stem. The roots of Dico-
tyledons increase in diameter by animal
layers of wood formed in the lihro-vaseular
bundles; these, however, aro much less
regular in their arrangement than those of
the stem on account of the tortuous course
of tlie roots ; hence, while the wood of the
roots is often useful for ornamental purposes,
it is comparatively valueless for carpenters'
uses. The branches of the axial root are
originally gTowths from the apex of the root
thrown oft to the sides as it were, and their
woody axis is derived from a division of
that of the main I'oot. Tlie radical of a
germinating Dicotyledon has its pileorhiza,
and grows, in the same way as that of the
Monocotyledons, by development of cells
just behind the apex. Young roots are
covered by a delicate epidermis ; and the
cells of this are abundantly produced into
hairs (fibrillfe) in many plants, especially in
those growing on light soils ; these fibrils
are deciduous, the delicate epidermis, which
is always destitute of stomata, being gra-
dually converted into a corky layer. Ad-
ventitious roots are very common in Dico-
tj'ledous, especially the herbaceous peren-
nial kinds, and they alone can exist on plants
raised from cuttings &c. of stems. The
roots originate much in the same way as
those of the Monocotyledons, appearing first
as cellular cones in the region adjacent to
the cambium -layer, with which the fibro-
vascular structure soon becomes confluent.
They break through the rind with a coleo-
rhiza, and protected by a pileorhiza, just as
in Monocotyledons ; but when once formed,
they appear to branch in the same manner
as the axial root, and not by the formation
of secondary adventitious roots.

The radicle of a monocotyledonous embryo
is never developed ; but if a section is made
of the lower part of the embryo, we find one
or more little conical bodies imbedded in
the parenchyma ; these are the nascent ad-
ventitious roots, which soon appear exter-
nally, breaking their way through the
superficial tissue. The anatomy may, how-
ever, be more easily studied by tracing the
development of the adventitious roots on
the rhizomes of rushes, flags, and other
plants of this class. The roots originate in
the region where the fibro-vascular bundles
of the stem terminate, (and frequently form
a fibrous plexus). They are first wholly
cellular, and consist of three parts : — a
woody axis Avhicli soon becomes continuous
with tlie fibro-vascular plexus ; a cortical

parenchyma, continuous with the inner part
of tliat of the parent stem ; and a kind of
conical hood of rather dense cellular tissue
enveloping the end of the root. As the
root grows it pushes the hood forward,
which breaks down the cellular tissue before
it, and finally appears externally. When
the epidermis is ruptured in tliis way, it
presents a circular free edge standing up
slightly like a coUar around the base of the
free part of the root : this is called the
coleorhiza by some authors. The conical
hood upon the apex of the root, called the
pileorhiza, is more or less persistent in dif-
ferent cases ; in aquatic plants it becomes
greatly developed, as may be seen in the
duckweed (Lenmd), where it forms a long
sheath, appearing as if slipped over the end
of the rootlet. The focus of development
of the root is within the pileorhiza, which is
pushed forward by the continued develop-
ment of cells just behind the apex. The
pileorhiza may be compared to a land of
shield or guard to the tip of the root, pro-
tecting the nascent tissue, by the expansion
of which it is pushed forwards, itself always
possessing a certain solidity, which enables
it to penetrate between the particles of the
soil.

The centre of the root of a Monocoty-
ledon is occupied by prosenchymatous tissue
with a circle of vessels around it, the whole
enclosed by regular parenchyma, sometimes
by liber-cells and covered by an epidermis.
The ring of vessels spreads out into a kind
of rosette at the base, and anastomoses with
the extremities of the fibro-vascidar bundles
of the stem in the fibrous region. Secon-
dary adventitious roots are formed in the
same way in the roots, originating imme-
diately upon the vascular ring and breaking-
through the cortical parenchyma. The
woody adventitious roots of arborescent
]Monocotyledons differ only in the greater
development of the fibro-vascular struc-
tures; and they emerge from the stem
(palms) in the form of thick conical shoots.
In the thickened adventitious roots of as-
paragus, which perform the function of
tubers, the parenchyma is greatly developed.
In the tuberous roots of Orchids the central
woody axis becomes ii-regularly expanded
into parenchymatous tissue, driving the
vessels out nearly to the periphery, so that
the characteristic structure is greatly dis-
guised. The aerial roots of the epiphytic
Orchids have the growing extremities
clothed by several layers of a parenchy-

ROTALIA.

[ 6G8 ]

ROTATION.

matous tissue, in which the cells are cha-
ractei'ized by delicate open spiral-fibrous
secondary la^er.-?.

iioots grow by cell-development only near
the apex; and interstitial expansion soon
ceases. Old roots of Dicotyledons present
a dense heart-wood like the trunks, the
passage of fluid taking place through the
outer layers. When the older parts of roots
are exposed to the air by removal of soil,
they acquire a thick corky periderm. The
general structure of the root of Conifers is
like that of Dicotyledons.

BiBL. Henfrey-Masters, Bot. ; Nageli and
Leitgeb, Nliy., Whs. Bot. 1867 ; Hofmeister,
Murphul. d. Gewi'h. 1865 ; Tieghem, Ann.
Sc. N. 5. xiii. ; Sachs, Bot. 165 ; Olivier,
Sac. teff. 1882 (50 pis.).

ROTA'LIA, Lamarck (restricted). — A
typical Foraminifer ; shell ammoniform,
neat, finely porous, unequally biconvex ;
with 1-3-40 chambers, double septa, and
canal-system ; limbate and often granulate.

Species numerous, both fossil and recent
(B. Beccarii, PL 24. figs. 13, 14).

BiBL. Carpenter, For. 212; Micr. 545;
Parker & Jones, Phil. Tr. civ. 387.

PtOTALI'NA, Carpenter {Eotalbue) .—
A subfamily of Globigerinida. See Foea-

MIXIFEBA.

BiBL. Carpenter, For. 198 ; Parker &
Jones, Phil. Tr. civ. 378, and Qu. J. G. S.
xxxviii. 103.

ROTATION or CYCLOSIS.— This terra
is usually employed in botanical works to
denote peculiar flowing movements of the
contents of vegetable cells ; and it is useful
to retain the word for all cases of the kind,
in order to avoid confusion of these pheno-
mena with the general circulation of the sap.
The term " circulation of the cell-sap " is,
however, often used instead of rotation, and
especially in reference to the cases where it
exhibits numerous distinct currents.

The rotation presents itself in two types,
namely — (1 ) a rotatory movement of a layer
of protoplasm investing the entire internal
surface of the cell, as in Chaba, «&c. ; and
(2) a radiating movement of the pi'otoplasm
in slender currents, from the nucleus out over
the remainder of the cell, with a return flow
towards the nucleus; but as the nucleus
itself shifts in the latter type as in the
former, tlie two kinds are scarcely definitely
distinguisluible ; they may, however, be
spoken of separately.

The rotation in Chara and Xitella has
been long known ; a .similar movement oc-

curs in many water-plants, such as Vallis-
neria, Hydrocharis, Anacharis, Sfraf.iofes,
Sayittaria, Potamoyeton,Ceratuphyllum, Sec,
where it is seen best in the more delicate
foliaceous structm'es, such as young leaves,
stipules, or sepals, or in the young rootlets.
It has also been observed in the fruit-stalks
of Blasia pusilla and some other Ilepaticie.

In the Chaeace^ the wall of the cells is
lined with chlorophyll-granules, leaving two
oblique or spiral striae bare (fig. 125, p. 162) ;
these sti-ise indicate the boundaries of the
ascending and descending currents (marked
by arrows) . The moviaig substance is a vis-
cid semifluid layer, lying within the chloro-
phyll-layer, and itself sniTOunding the
watery cell-sap occupying the centre of the
cell. This layer, forming a kind of gelatinous
sac, moves in a spii-al com-se up one side of
the cell and down the other, the motion
being rendered very evident by chlorophyll-
and other gi-anules imbedded in it ; these
appear to be carried along passively by the
stream, the larger slowly, the smaller with
greater rapidity. In Vallisneria, Anacharis,
&c. the chlorophyll-granules and the nu-
cleus are imbedded in and moved with the
flowing protoplasm. If long cells of Chara
are bent or tied round by a ligatm-e, the
circulation is not stopped, but takes place
independently in each half. If a cell of
Chara is cut across, the protoplasm of the
current flowing towards the cut surface
escapes at once, but that of the current
flowing away, goes on to the end of the
cell, turns round, and then flows towards
and out from the wound.

The size of the stream seems to be in in-
verse proportion to the length of the cell,
decreasing as the latter acquires its I'uU
development. The rapidity of the current
varies according to the age of the plant and
the activity of its vegetation. It is most
rapid in hot weather and in sunshine. Arti-
ficial elevation of temperature in the water
in which the plant grows, up to a certain
point, hastens the movement; a heat above
80° Fahr., however, retards it for a time.
A temperature of 112° Fahr. kills the plant,
as also does a cold of about 20°. Darkness
appears merely to exert eflect through its
influence on the activity of the vegetation.
Keeping Chara in water exhausted of air
does not stop the rotation until the plant
dies. Most chemical reagents seem to exert
no special action ; only lime-water appears
to stop it in a few moments. A solution of
sugar, or gum, or milk greatly hastens tlie

ROTATION.

[ 669 ]

ROTATORIA.

rotation in Vallisnerut, &o that the proto-
jihisni is moTod on in waves ; but the pri-
mordial utricle finally dissolves, and the
movement ceases, rassing: an electric cur-
rent through the cell stops the current for
a time ; but it recovers itself, just as occurs
after any mechanical interference. If several
cells are injured by cutting- or pricking, the
whole rotation stops in young plants, but it
gradually returns as before in the uninjured
cells. Pressure inteiTupts or stops the mo-
tion for a time only ; when removed, the
current is gradually restored ; but actual
injuiy to the cell stops it for ever.

The rotation which takes place between
the external surface of the green layer and
the outer cell-membrane in Closterium and
other Desaiidiace^ appears to be of the
same kind as the above.

The circidation in reticular currents, first
observed by Brown in the hairs of the
stamens of Tmclescantia, appears to exist
far more extensively, if it be not even a uni-
versal phenomenon. It has been observed
in the Coufervoideae, Fucoide;^, Floridese,
Lichens, Fungi, Hepaticas, Equisetacese,
Lycopodiaceo9, and Ferns, and in the most
varied families of Flowering plants. It is
seen most easily in young tissues, especially
such as can be prepared readilj^ without
much mechanical injury ; for example, in
hairs, cells of the pulp of fruits, cells of the
germen of Onagi-aceae, of the labellum of
Orchids, &c. It generally exhibits the fol-
lowing characters : — In the middle or at one
side of the cell occurs a large heap of pro-
toplasm, in which is imbedded the nucleus ;
from this protoplasm more or less slender
filaments run out over the cavity of the cell,
and as these contain numerous fine granules,
a flowing movement which takes place be-
comes evident by the change of place of the
granules. Attentive examination shows that
these flow out from the central mass and
return to it, and, moreover, that the cur-
rents change their form and direction, and,
lastly, that the nucleus itself moves. This
rotation cannot be observed in very young
cells when the cavity is densely filled with
protoplasm ; but Hofmeister states that he
has seen the entire primordial utricle rotate
in the special parent cell of the spore of
I'hascmn cuspidatum. As the young cells
increase in size, vacuoles are formed in the
protopla,sm,filled with watery sap ; and these
enlarging and becoming confluent, leave the
protoplasm in the form of a reticulated
mass.

The cause of the motion is evidently
related to the movements exhibited by free
protoplasmic bodies, such as Zoospores,
Sprumatozoids, the free filaments of Os-
ciLLATOniA, &c. It has been well com-
pared with the movements of the body of
Amoeba, which bear considerable resem-
blance to some kinds of the reticular I'ota-
tion. The relation existing here is further
borne out by the fact of pulsating vacuoles
existing in Volvox, Gonium, &c., j ust like
those in the Infusoria.

The actual rotation or movement in a
definite direction is the result of the con-
fining cell-wall on the contracting and ex-
panding protoplasm. It is produced in
Algoe clurmg cell-growth.

The rotation in CJiara may be observed
by simply placing portions of the plant on a
slide in water. The unincrusted species are
of course most favourable ; but the growing
points of the others are tolerably transpa-
rent. In Viillisneria, detached fragments of
leaves, or even horizontal sections of the
leaf, may be used ; in A7iacharis, entire
leaves or sepals may be detached and ol>
served. Hairs are frequently more or less
covered with a viscid secretion, which re-
tains air-bubbles about them ; in such
cases, it is often useful to dip them for an
instant in alcohol, and then place them in
water.

BiBL. Varley, Tr. Soc. Arts, xlviii. ; Mic.
Trans. ; Slack, Tr. Soc. Arts, xlix. ; Du-
trochet, Compt. Bend. 1837, 775 ; Becque-
rel, ibid. 784 ; Unger, Sitziingsber. Wien.
Ak. viii. 32 ; Moh], Bot. Zeit. iv. 73 ; Ann.
N. n. xviii, 1 ; Hofmeister, Venj. Unters.
73 ; Osborne, Mic. Jn. iii. 64 ; Branson,
ibid. iii. 260; Weuham, Hid. iii. 250; Hen-
frey, Ann. N. H. 3, i. 419; Reichert, Ann.
N. H. 1867, xix. 10 ; Beale, How ^-c. 4th
edit. 165 ; Carpenter, Microscoi^e ; Henfrey-
Masters, Bot. 551.

ROTATO'RIA or ROTIF'ERA. — A
Class of the Animal Kjngdom.

Char. Microscopic, transparent animals,
living in fresh or in salt water ; legs absent ;
anterior portion of the body furnished with
one or more retractile, often lobed disks,
upon which are placed usually vibratile
cilia, when in motion presenting the appear-
ance of one or more revolving wheels ; ali-
mentary canal usually distinct, with a den-
tal apparatus, and two orifices; reproduction
by ova.

Body covered with a firm and usually
smooth skin or integument, sometimes pre-

ROTATORIA.

[ 670 ]

ROTATORIA.

sentiug indicatious of segments ; often more
or less enclosed in a carapace (Carapace),
which is either secreted by the skin, by the
aHmentary canal, or by a special secreting
organ. In some species the skin is fur-
uislied with cilia, hairs, or rigid bristles.

In most, there is a tail-like process at the
posterior end of the body called the foot-
like tail, tail-like foot, or false foot ; this is
jointed, and can often be contracted and
extended like a telescope ; it does not form
a direct prolongation of the end of the body,
bnt arises from and is situated upon the
ventral aspect. It is often terminated by a
suctorial disk, or a pair of claw- or toe-like
processes.

Distinct longitudinal and circular muscu-
lar bands are present ; and they sometimes
present transverse striae.

The rotatory disks or wheel-organs vary
greatly in structure, the varieties forming
characters of the families and genera.

Their margin is usually furnished with
one or two rows of vibratile cilia; some-
times these are replaced by bundles of non-
contractile elongate cilia (PL 43. fig. 32),
or the I'otatory organ is divided into ten-
tacle-like processes, upon which cilia are
placed (PI. 44. fig. 25).

The rotatory disk is tlie principal organ
of motion, by means of the cilia of which
the animals swim through the water; some
of the Rotatoria, however, move in a leech-
lilce manner, by alternately fixing the toe-
like processes and the anterior end of the
bod3% which in some forms a kind of pro-
boscis (PI. 43. fig. 1).

The nervous system is not well known.
It appears to consist of a ganglion and of
branches given off iu various directions.

In many of the Rotatoria, eyes are pre-
sent, mostly red. These appear to have a
cornea and a lens. They sometimes dis-
appear iu the adult animals ; and as their
number, position, &c. are used as charac-
ters, when absent in the adults, they nuist
be looked for iu the young or the ova,
either within the carapace or adherent to
the body.

AlimenUiri/ apparatits, — Behind the mouth
is sometimes a distiuct conical pharynx,
but nearly always a rounded muscular giz-
zard containing the jaws and teeth. In the
pharynx are occasionally seen two undula-
ting lines, presenting a lliekeriug appearance,
the indications of cilia or undulating mem-
branes. The jaws are constructed mostly
after two forms. In one of these they con-

sist of two knee-shaped ]iieces (PI. 43. fig.
24), — to the posterior portion of which
nmscles are attached, whilst the anterior,
which passes inwards at a right or obtuse
angle to tlie former, ends in a single point
or in several teeth (fig. 26). In the other,
the jaws have the form of stirrups (fig. 17),
with their bases turned towards each other,
upon which two or more teeth are placed.
A third single or compound intermediate
piece forms a support (figs. 24, 26), upon
which the food acted upon by the jaws
is triturated. In some species the jaws
and teeth are very complex in their ar-
rangement.

The alimentary canal is usually short and
straight, but sometimes curved. Its walls
are very thick, and lined with ciliated epi-
thelium. The stomach forms a distinct
expansion (PI. 4^3. fig. 27 c) ; this is suc-
ceeded by an intestine, the termination of
which corresponds to a cloaca, receiving the
expelled contents of the reproductive organs
and so-called water- vessel system, and open-
ing at the base of the foot. In some Rota-
toria a second expansion or stomach is situ-
ated below the upper one.

The walls of the stomach and intestines
frequently contain brown or yellow cells,
representing a liver ; and at the commence-
ment of the stomach are two or more crecal
appendages, probably corresponding to a
pancreas (PL 44. fig. 14).

In the male Rotatoria, the alimentary
canal is entirely absent.

Vascular sydem. — Distinct blood-vessels
are apparently not present in the Rotatoria ;
but on each side of the body, in most of
them, runs a narrow straight or waxy baud,
containing a slender vessel (PL 43. fig. 18 a;
PL 44. fig. 14 b). Anteriorly, these vessels
give oft'branches, the terminations of which
are not well known. By some they are said
to open into the abdominal cavity, by others
to terminate as casca. Attached to the walls
of these lateral tubes, or situated within
them, are pear-shaped or oval corpuscles
(PL_ 4^3. fig. 18 a ;_ PL 44. fig. 14 c), which
exhibit a fiickering appearance from the
action of cilia connected with them, and
which open into the cavity of the abdomen.
I'osterioily, the tubes terminate in an ac-
tively contractile sac, which opens into the
cloaca. In regard to their fimction, these
tubes have been variously viewed as water-
vessels, testes, and kidneys. I'^lueuberg con-
sidered them as connected anteriorly with
a certain projecting organ (PL 44. fig. 14 a),

ROTATORLi.

[ ^71 ]

RUCKERIA.

situated usually in the cervical region (PI.
43. lig. •■> ; PI. 44. fig-. 17), denominated the
calcar or respiratory tube, and terminated
by a retractile tuft of nou-vibratile cilia
(tig. 5 a). They have no relation, how-
ever, with this, Avhich corresponds to an
antenna. Huxley proved that they are
part of a water-system.

Beneath the inteo-ument of the Rotato-
ria, a kind of irregular circulation, varying
with the motions of the body, or a simple
molecidar movement of minute granules, has
been noticed. These granules are probably
situated in the abdominal cavity ; in which
also sarcodic globules, sometimes free, at
others connected by filaments, have been
observed.

Reproduction. — The Rotatoria are propa-
gated by means of sexual organs, and are
unisexual. The female organs consist of
one or two longer or shorter ovarian sacs or
ovaries, situated towards the posterior end
of the body in the abdominal cavity, the
oviduct terminating in the cloaca, or at a
distinct A-ulva. The ova are of an oval
foiTu, and are sometimes smooth externally
and soft. The -s^-inter-ova are larger and
darker than those hatched during the sum-
mer, and the outer coat is thick and hairy
or tubercular. The winter-ova which re-
main so long attached to the posterior part
of the body are probably gemmie ; they
sometimes remain adherent to the cloaca
for a time, and in a few instances they are
hatched Avithin the ovary.

The testis is situated at the posterior
part of the body, and consists of a wedge-
shaped body, with a muscular duct opening
externally.

Many of the Rotatoria are remarkably
tenacious of life ; and some of them are
stated to have revived after having been
kept dr}' for several years.

Perfect desiccation destroys the Rotifers,
but they wiU last a long time with a very
slight amount of moisture.

The families of the Rotatoria are thus
distinguished : —

Ciliated margin of rotatory disk simple or continuous.
Margin entii'e. Solotrocha.

Carapace absent Iclithydina.

Carapace present • Qiciatina (?) .

Margin undulate or excised. Schizotrocha.

Carajiace absent Megalotrochsea.

Carapace present Floscularieea .

Rotatory disk divided or multiple.
Divided into several parts. Polyifocha.

Carapace absent Hydatincea.

Carapace present TiuchlauJdota.

Divided into two parts. Zygotrocha .

Carapace absent Philodinasa.

Carapace present Erachionsea.

See Albebtina.

They are found wherever water exist%
provided it be not in a state of putrefaction,
— thus iu pools, on moist earth, mosses, in
gutters, &c., and even in the cells of mosses
and alga).

BiBL. Ehr. Inf. ; Dujard. Inf. ; Siebold,
Verf/l. An. ; Dalrvmple, 'Phil. Tr. 1849, 331 j
Huxley, Mio: Trans. 1852, i. 1 ; William-
son, Micr. Jn. i. 1 ; Cohn, Siebold mid Kdl-
likers Zeitsch. vii. 431 ; Gosse, Tr. Micr.
Soc. iii. ; id. Ann. N. H. 1851, viii. 198
(several new genera and species) ; and 185G,
xviii. 333; Pritchard, /«/". ; Schmarda, Ncne
Rotatoria, 1861 ; Mecznikow, Sieh. und KoU.
Zts. 1865; Qu.Mic. Jn. 1666, 34 & 240;
Claparede, An. N. II. 1868, i. 309 ; Schloch,
Riiderthiere, 1869 ; Cubitt, M. M. In. vi.
168, viii. 5; Hudson, M. M. Jn. xiii. 45;
Pascoe, Zool.

ROT'IPER, Cuv. — A genus of Rotatoria,
of the family Philodinjea.

Char. Eyes two, situated upon the pro-
boscis ; foot furnished with lateral horn-
like processes, and with t\\o terminal toes,
giving its end a bifm-cate appearance; fresh-
water.

R. vul(/aris (PI. 44. fig. 23). Body fusi-
form, white, gradually attenuated towards
the foot J length 1-48 to 1-24".

This is one of the commonest of the
Rotatoria, and has long been linown as a
favourite microscopic object under the po-
pular name of the wheel-animalcule. The
anterior and upper part of the body termi-
nates in a proboscis, ciliated at the end, and
upon which the eyes are placed ; the two
rounded lobes of the rotatory organ are
placed laterally. Behind, and at the root
of the proboscis, is the calcar.

In R. citrinus, the middle of the body is
yellowish, the horns of the foot long, and
the eyes round. In R. macrurus, the body
is suddenly narrowed into a long foot. lli
R. tardus the body is gradually attenuated,
but somewhat deeply constricted into seg-
ments.

BiBL. Ehr. Lifus. 484 ; Pritchard, Inf. ;
Greuacher, M. Mic. Jn. 1870, 44.

ROTIF'ERA, See Rotatoeia.

RUBEFACTIOX of AVatek. See
Water.

RUCKE'RIA. — A genus of Computitce.
The pericarp possesses HAUiS of an inter-
esting structui'e.

RUELLIA.

[ 072 ]

SALICOENARIA.

BiBL. Decaisne, Ann. Sc. Nat. 2. xii.
251 ; Ann. N. H. vi. 257.

RUEL'LIA. — A genus of Acaiitliaceous
plants. The testa of the seed of JRnellia
formosa exhibits a peculiar kind of Haxr,
*(P1. 28. %. 21).

RUST OF Plants. See Blight.

RUTILA'RIA, Gr.— A genus of Diato-
macese. Frustules compressed, forming a
short filament ; valves elliptical, elevated at
the angles, with a central nodule, termina-
ting in two short processes ; margin spinous.
3 species ; in the Barbadoes deposit. (Cire-
ville, Tr. Mic. Soc. 186G, 124.)

RYE. — The grain of Secak cereale. See
Starch.

RYLAND'SIA, Gr. & Ralfs.— A genus
of Diatomacete. Frustules simple, disk-
shaped, areolar ; valves with two opposite
smooth raJ^s, dilated at their base, not
i-eaching the centre. R. hiradiata, Barba-
does deposit. (Greville, Qu. Mic. Jn. 1861,
67.)

RYTIPHLCE'A, Ag.-A genus of Rho-
domelaceae (Florideous Algse), containing
fovu" British species, mostly common, having
pinnately branched, filifoi'm or compressed
fronds, transversely striate and reticulated ;
the articulate axis is composed of a circle of
large elongated tubular cells surrounding a
central cell, the whole enclosed by a kind
of rind of several layers of small coloured
cells. Colour mostlv dull red or brown.
Fronds from 2" to 4" or 6" high. Cem-
midia scattered on the ramules of some
plants ; antheridia tufted in the same situ-
ations on others ; and tetrahedral tetra-
spores occur imbedded in a double row in
stichidia, borne on distinct plants. R. trinas-
truidcs (PI. 4. fig. 11).

BiBL. Harvey, Mar. Alrj. 80 ; Grev. AJg.
Br. ; Derbes and Solier, Ann. Se. Nat. 3.
xvi. 275 ; Thuret, ibid. 4. iii. 20.

S.

SACCAM'MINA, Sars. See Littjolida.

SACOOG'YNA.— A genus of Junger-
mannieae (Ilepaticoe) founded on Jumjer-
mminia viiicidosa of Linnteus ; it is re-
markable on account of the subteiTaneous
fleshy perianth, in which character and in
habit it is allied to Cab/jw(/eia. It is found
among mosses, especially in alpine districts.

BiBL. Hook. Rr.Fl. ii. pt. 1. 121; Br.
Junr/. pi. GO ; Ekart, Syn. Jun/f. pi. 1. fig. 6;
Eudlicher, Gen. PL Supp. 1. iNo. 472-23.

SAC'CULUS, Gosse.— A genus of Rota-
toria, of the family Ichthydina.

Char. Eye single, frontal ; body free fi-om
hairs, and mthout a foot ; rotatory organ a
simple wreath ; alimentary canal very large ;
jaws set far forward, apparently consisting
of two delicate unequal lateral pieces, and
a slender central portion, very evanescent ;
eggs attached behind after deposition.

*S'. viridis. Length 1-150" ; freshwater.

BiBL. Gosse, Ann. N. H. 1851, viii. 198.

SADLE'RIA, Kaulf — A genus of Blech-
neae (Polypodiaceous Ferns). Two species;
arborescent; Sandwich Islands. (Hooker,
Syn. Fil. 187.)

SAGENEL'LA, Brady. —A simple,
branchmg, Arenaceous Foraminifer, at-
tached to NuUipores, forming a network
with its anastomosing branches (1-200" to
1-65" in diameter). Admiralty Islands.
(Brady, Qu. Jn. Mic. Sci. n. s. xix. 41.)

SAGO. — Farinas obtained from a variety
of tropical plants are known by this name';
but the true East-Indian sagoes are ex-
tracted from the central part of the trunks
of Palm-trees belonging to the genus Sayns,
natives of the Moluccas. In PI. 46. fig. 23,
is figured the starch of a sago obtained'
from the Museum at Kew; but it is un-
certain whether this is the produce of a
Sayus; its grains resemble those of some
East-Indian Arrow-roots (PI. 46. fig. 18).
See Starch.

SAGRI'NA, D'Orb. (Sagraixa, Reuss).

See UviGERINA. •

SAL A 'CIA, Lamx. — A genus of La-
foeidse, Hydi-oid Zoophytes.

Char. Stem erect, composed of aggregated
tubes, branching, rooted. Cells cylindrical,
sessile, without operculum, aduate fur the
greater part of their length, on all sides of
stem and branches in regular longitudinal
rows. Ovicells scattered on the stem and
branches. Polypes long, cylindrical, with
a conical proboscis.

'S'. abietina. Deep water oft" Northumber-
land coast. (Hincks, ^yr/. Zoojih. 211.)

SALICINE. — The alkaloid of the willow
and poplar.

The so-called circular crystals of this
substance (PI. 39. fig. 9) form a beautiful
polarizing object. The largest crystals are
obtained bv fusion.

SALICURNA'RIA, Cuv.-A genus of
Chcilostomatous Polyzoa.

Char. Surface divided into rliomboidal
or hexagonal spaces by ridges sarn.undiug
the cells : avicularia disposed irregularly.

SALICORNARIID.E.

[ 673 ]

SAND.

S. farcimifioides. On old shells, &c. from
deep water, not uncommon.

BiBL. Johnston, JBr. Zocph. 355; Busk,
Cat. Mar. Polyz., Brit. Mas., 16; Heller,
Verhandl. zool.-bot. Gesellsch. Wieti, svii.
1867, 85 ; Hincks, Pohiz. 104.

SALICORNARI'IDyE. — A family of
Infundibulate Cheilostomatous Polvzoa.

Char. Polvpidom erect, branched, jointed;
branches cylindrical, dichotomous, with the
cells on all sides. One genus :

Salicoknaria.

SALIVA and SALIVARY GLANDS.
— These organs, consisting of the parotid,
the submaxillaiT, and the sublingual glands,
agree essentially in structure with the race-
mose mucous glands (Mouth), of which
thev may be regarded as aggregations.

Their 'ducts consist of connective tissue,
with numerous very dense networks of elas-
tic tissue. "Wharton's duct contains un-
striped muscular fibres.

The salivary corpuscles are noticed at

page 518.

SALMON-DISEASE. See Achlya.

SALPI'NA, Ehr. — A genus of Rotatoria,
of the family Euchlanidota.

Char. Eyes single, cervical ; foot forked ;
carapace closed on the ventral surface, and
furnished with spines or horns at the ends.
Freshwater.

The carapace resembles a three-sided
box with convex sides, flat and closed
beneath, and often scabrous.

S. redunca (PI. 44. fig. 24). Carapace with
two curved horns in front upon the ventral
surface, smooth, posterior, end with three
horns; dorsum cleft, gaping. Length of
carapace 1-216 to 1-144".

Five other species.

BiBL. Ehr. Inf. 469 ; Pritchard, Infus.

SALPIN'GIA, Coppin.— A genus of
Cheilostomatous Polyzoa, of the family
Eucratiidse.

Char. Erect, branched ; cells elongate,
with spines and trumpet-shaped processes ;
orifice lateral. One species :

S. HassallU. On filamentous fuci ; rare.

BiBL. Coppin, Ann. N. H. 1848, ii. 273.

SALPINGCE'CA, J. Clark.— A genus of
Choano-Flagellate Infusoria. Single, in a
fixed sessile or stalked, ovate or flask-
shaped carapace. 29 species, marine and
freshwater ; attached to Algse, shells, &c.

<S'. amphoridium (PI. 53. fig. 25). Fresh-
water, on Conferva! &c. : length 1-3350".
(J. Clark, Mem. Bost. Soc. i. 1668 ; Kent,
Jnf. 340.)

SALTS. See Crystals.

SAL'VIA, L. — An extensive genus of
Flowering plants, of the Nat. Ord. Labiat;©,
including common sage, and many species
cultivated for the beauty of their flowers.
They are interesting to the microscopist
both on account of the glandular liairs,
containing the essential oils, and the spiral-
fibrous structures foimd in the hairs of the
pericarp (PL 28. fig. 23) and the hairs of
the stigma.

SALVIN'IA, Mich.— A genus of Mar-
sileacese, growing floating on the surface
of stagnant water (not British).

The fructification resembles tliat of 3Iar-
silea and Pihdaria, except that the antlie-
ridia and sporangia are contained in sepa-
rate sacs, and also attached to a sort of
central cellular stroma. The pro thallium
of Salvinia produces several archegonia.
See Marsileace^ and Pilularia.

SAND, Brain-. — Brain-sand, or the acer-
vulus cerebri, is found
in the pineal gland and
the choroid plexus,
sometimes also in the
pia mater, the arach-
noid membrane, and
the walls of the ven-
tricles.

It consists of single,
or aggregated and no-
dular, rounded, dark
bodies,l-2500 to 1-200"
in diameter, sometimes
also forming club-
shaped, cylindrical, or
reticular masses. It is
principally composed
of carbonate and
phosphate of lime, and,
like other concretions,

Fig. 623.

Brain-sand from the
pineal gland, in bundles
of areolar tissue.

leaves an organic cast

Magn. 350 diams.

of the original form,
after the salts have been removed by a di-
lute acid.

BiBL. KoUiker, Mikr. Anat. ii.

SAND, Sea-. — This often contaiua
interesting microscopic objects, a,s Fora-
minifera, spicules of sponges, minute shells
of the Mollusca or their fragments, portions
of the skeleton of the Echinodermata, &c.

The various bodies may be separated
from the washed and dried sand with a
mounted bristle.

The sand or powder which may be
separated by pressing or shaking newly
imported sponges, and which is sometimes

2x

SANDSTONE.

[ 674 ]

SAROOBE.

called spouge-sand, is very rich in the above
organic bodies, especially the Foraininifera.

SANDSTONE. See Rocks.

SAN'IDINE. See Rocks.

SAP. — A name vaguely applied to the
watery juices contained in living plants.
Sap tiowing from wounds may contain
various organized substances, such as starch-
granules, chlorophyll-globules, protoplasm,
and also raphides ; but it cannot be said to
have any proper microscopic characters.

SAPROLEG'NIA. See Achlya.

SARACENA'RIA, Defrance.— A short,
thicli, triangular modification of Cristellaria.
Recent and fossil. (Parker and Jones, Ann.
N. H. 3. xii. 217.)

SAR'CINA, Goodsir. — A curious organ-
ism, formerly placed among the Palniel-
lacete from considerations relating to its
structure, but which, from its habitat and
general characters, is now referred to the
Schizomycetous Fimgi. Sarcina venfnculi
(PI. 7. fig. 5 a and b) is sometimes found in
great abundance in the vomited contents of
the stomach of the human subject, also in
the stomach after death, where no disorder
had appeared during life. It consists of
minute, cubical, oblong, or even irregular
masses, of considerable consistence, com-
posed of four, eight, sixteen, sixty-four or
more, squarish cells contained in a tough
transparent frond, apparently composed of
the ceU-membranes of these cells. The
cells are always most closely connected in
groups of foiu-, which stand a little more
apart from each other in the secondary
groups of sixteen ; these again have a
stronger line of demarcation between them
when they are collected into tertiarv groups
of sixty-four (PL 7. fig. 5 a, b). The size
of the primary cells, or nuclei of Robin
appears to vary slightly ; we find their
diameter about 1-16,000"; they have a
slight brownish tint, which imparts a colour
to the whole mass. Iodine colours the
fronds brown ; alcohol contracts them a
little. Nitric acid does not dissolve tliem,
even when heat is applied. Alkalies cause
the fronds to break up into their constituent
components. The plant appears to increase
by the division of the contents of its ulti-
mate cells into four and the formation of a
new membrane around each portion, the
groups remaining attached a longer or
shorter time according to circumstances.
Berkeley has in vain tried to get it to ger-
minate in sugar and water.

It is stated to have been found also in the

lung, and the pus of pulmonary abscess, the
blood, the urine, the ffeces, and in the sto-
mach of the rabbit. According to Ferrier,
it is normal or constantly present in the
blood of man and animals ; and may be
readdy obtained by keeping blood in tubes,
stopped with wool, for a week or ten days,
at a temperature of 100°.

We have never found it, except in the
contents of the stomach.

Robin and Rabenhorst place Sarcina in
the genus Merismopcedia ; but its cubical
form and the absence of chlorophyll at once
separate it.

BiBL. Goodsu', Ed. Med. and Surff. Jn.
1842, 430 ; An. and Path. Obs. 184-5 ; Na-
geli, Eitiz. Alg. 2 ; Robin, Veg. Parasit. 331 ;
Rossniann, Flora, 1857, 641 ; Stephens,
Ann. N. H. 2. xx. 514 ; Ferrier, Qu. Mic.
Jn. 1872, xii. 163 ; Lorstofer, Wien. Jahrb.
1872.

SARCOCH'ITUM, Hass.— A genus of
Infundibulate Ctenostomatous Polyzoa, of
the family Alcyonidiidse.

Char. Incrusting, covered with perforate
prominences in which the cells are im-
mersed; ova scattered singly throughout.
One species :

S. ]}olyoum. On Ftieus serratus.

BiBL. Hassall, Ann. N, H. 1851, vii. 484;
referred to Alcyonidium.

SARCODE.— A termappUed byDujardin
to the gelatinous, homogeneous, diaphanous
proteine substance occurring abundantly in
very j'oung animals, the larvae of insects,
embryos of the Vertebrata, worms, zoo-
phytes, &c. ; it is synonymous with proto-
plasm. It constitutes the whole of some
of the lower animals, as the Aincehce. It
may be readily studied when exuding from
aroiuid the body of the intestinal parenchy-
matous worms, as Disfovia, Ci/sticercus,
Tce^tiia, &c., or almost any of the Infusoria,
placed alive in water between two plates of
glass. In the course of a short time, the
bodies of the animals are seen to be bordered
with a row of projecting diaphanous glo-
bules (PI. 32. fig. 2 a), frequently more or
less pressed together, which after a time be-
come separated and float in the liquid, espe-
cially it it be shaken. Spherical cavities
or vacuoles are soon perceptible in tliese
globules of sarcode (PI. 32. fig. •2b), the
nature 'if which is readily determined by
comparing the refraction of the light at
their circumference with that at the cu'cimi-
ference of the globules themselves ; for on
elevating the object-glass, the centre of the

SARCONYSSUS.

[ 675 ]

SARCOSCYPIIUS.

vacuoles becomes darker, and the centre of
tlie fi-lobules becomes brighter ; whilst on
approximating the object-glass, the reverse
takes place. The spontaneously produced
cavities continue to enlarge and increase
in numbers, until some of the globules
appear perforated in all directions. Ulti-
mately the globules become so altered by
the action of the water, that they form a
thin granular or wrinkled layer, resembling
coagidated albumen.

The protoplasm of vegetable cells corre-
sponds to the sarcode of animal structures.
In certain cells it exists in two forms as
regards density, the outer portion being
firmer than |tlie inner; or it .may become
entirely liquid. In many of the lower
organisms, and probably most cells in their
youngest state, it is glutinous, and in the
former, permanently remains so.

^^'hen existing in cells and the lowest
animals, it appears to constitute the essen-
tial part of their structm-e, and is capable
of performing all the functions carried on
by the tissues of the higher or more per-
fect organisms. It also appears that the
cell-theory, in so far as it attributes the
principal importance to the cell-wall, is
founded upon error — the cell-wall merely
forming a protection to the sarcode or pri-
mordial utricle of plants, and the sarcode,
or protoplast as it might be called, of ani-
mals, enabling them to carry on their
essential functions uninterrupted by sur-
rounding influences (1st Ed. 1856).

BiBL. Dujardin, Infus. p. 36.

SARCONYS'SUS, Kol.— A genus of
Ixodea, with the terminal joint of the
palpi rounded or oval ; 4 species ; on bats.
(Kolenati, Siiz. Ah. Wien, 1860, 576 ; Mur-
ray, Ec. Ent. 195.)

SARCOPSILLUS, Westw.— A genus of
Aphauiptera. One species, on the fowl.
(Westwood, £■«/. Mn.Mag. 1875, xi. 246.)

SARCOP'TERUS,Nitzsch.— Asubgeuus
of Sarcoptes. In the two anterior pau-s of
legs, the suckers are replaced by claws, and
in the posterior bv hairs. »S'. nidulans, in
birds. (Murrav, Ec Ent. 314.)

SARCOP'TES, Latr.— A genus of Arach-
nida, of the order Acarina, and family Acarea.

It is, by some authors, considered a family,
being divided into several genera, as Sarcop-
tes, Symhistes, Sarcopterus, Myobia, Oto-
nyssus, Ltstrop/iortcs, Myocojiies, and Der-
Dialeichus.

S. scabiei (Acarus scabiei, PI. 6. tig. 16) ;
the itch-insect of man.

Body soft, white, oval-oblong or rounded ;
ventral surface witli transverse and undula-
ting ruga3 ; dorsal surface with marginal
irregidarly concentric rugaj, the central
space with numerous short and conical pa-
pillie and stouter but short protuberances
or spines arising from an annidar base ; at
the sides and upon the surface of the body
are also scattered setse. Head smaU, some-
what narrowed in front ; mandibles toothed.
Anterior two pairs of legs separated from
the posterior by a considerable interval ;
legs short, the anterior two pairs with aceta-
bula or adhesion-disks and tive-jointed, the
posterior three-jointed, the last joint termi-
nated by a long seta and without acetabula.
Length of female 1-100 to 1-75".

The females burrow in the skin, in which
the oval eggs, 1-120" in length, are laid;
these are hatched in about ten days, and
the yormg have only six legs.

Male only about half the size of the
female, and with acetabula to the hinder-
most pair of legs.

The irritation produced by these mites
and their ova is the cause of the itch.

They shoidd be searched for at the end of
one of the red streaks or burrows, which are
often visible to the naked eye ; the ova are
frequently present in the pustides. They
are most easily found by examining the
skin with a power of fifty to seventy dia-
meters, attached to a firm but moveable
arm, and with the aid of a good bull's-eye
condenser.

The entii'e animals may be preserved in
glycerine or solution of chloride of calcium ;
the parts of the mouth should be dried and
mounted in Canada balsam.

Other varieties or species occur upon ani-
mals, as the dromedary, the chamois, the
dog, sheep, rabbit, kc,

BiBL. Bourguignon, Traite de la Gale
(abstract in Ed. Monthly Journ. 1852, Ix.) ;
Gervais, Walckenaer^s Insect., Apt. iii. 2G8,
and Ann. Sc. Nat. xv. 9 ; Hering, Kriitz-
milhen d. Thieve, Nov. Act. xviii. 573 ; Du-
ges, A)in. Sc. Nat. 2. iii. 245 ; Fiirstenberg,
Kratzmilhen ; Murray, Ec. Ent. 291; Meg-
niu. Paras. 158.

SARCOS'CYPHUS, Corda.— Agenus of
Jinigermanniese ( Hepaticpe) . »S'. Ehrharti
(Jif/iy. enianjinata, Ehrh.) is a remai'kable
species, of dark purple, almost black colour,
growing frequently in wet places, on rocks
of mountainous districts.

BiBL. Hook. Brit. Flur. ii. pt. 2. p. ]14;
Brit. Juny. pi. 27; Ekart, Synops. Jung.

2x2 ,

SAEGASSUM,

[ 676 ]

SCALES.

pi. 7. fig. 56, and pi. 13. fig. 113; Endliclier,
Gen. riant. Supp. i. nos. 474-1.

Fig. 624.

Fig. 625.

.^^^sK^fflrr^,

%

Sarcoecyplius Ehiharti.

Fig. 624. Perithoete and perigoue opened, stowing the
young sporange emerging from the epigone. Magnified
25 diameters.

Fig. 625. Perichiete and perigone opened, show ing the
ba>e of the seta surrounded by the epigone. Magmlied
10 diameters.

SAP.GAS'SUM, Ag.— A gemis of Fuca-
cete (Fucoid Algae), gulf-weeds, known
from the allied sea-weeds by its stalked
globular air-vessels. The receptacles are
small, linear, and mostly clustered at the
base of branches, and pierced by numerous
pores leading to conceptacles, containing
spore-sacs and clusters of autheridia (see

FUCACE^).

BiBL. Harvey, Brit. Mar. Alg. p. 14,
pi. 1 A ; Greville, Alg. Brit. pi. 1.

SCALAEIFOEM VESSELS. See
Spiral Strtjctubfs.

SCALES OF Fishes. — These bodies
were formerly regarded as epidermic ft)rma-
tions, analogous to the nails, &c. of the
higher animals, which later observations
have shown not to be the case.

Each scale is contained in a distinct sac
of the skin or cutis, covered externally with
its pigment-layer and epidermis. The cutis
itself consists of interlacing fibres of areolar
tissue with formative cells. The piiiment-
layer is composed of elegant pigment-cells
with long prt)cesses. Immediately above
the upper surface of the scales lies a very
fine membrane, distinct from the cutis, in
which the impressions of the irregularities
of surface existing upon the scales are
visible.

In some fishes, as the eel, the scales do
not project beyond the surface ; hence the

eel is commonly supposed to possess no
scales. They are easily seen, however, in a
dried piece of the skin, mouutt'd in balsam,
covered by the skin with its pigment-cells
(PI. 22. fig. 19), the whole forming a very
beautifid object.

In many of the common cycloid fishes, as
the roach, dace, &c., the scales projects pos-
teriorly from the sm-face, carrying before
them the thinner and closely applied outer
layer of the cutaneous sac, whilst the ante-
rior portion of the sac extends into or is
formed bj' the under portion of the cutis.
In these fishes also, the portion of the cutis
situated beneath the posterior projecting
portion of the scales contains a large num-
ber of very thin and minute crystals, to
which the silvery lustre of the skin is owing,
and which often exhibit very beautifully the
colours of thin plates.

The signification of the various parts of
structure of the scales has not been satis-
factorily determined ; hence we must con-
fine our remai-ks to simply pointing out the
structural peculiarities.

Most scales consist of two portions, — an
under, composed of numerous layers made
up of very fine fibres taking various direc-
tions, and best seen by scraping away the
upper portion of the scale after maceration
in dilute acid (PI. 22. fig. 11 a). The upper
portion consists of concentric plates, the
margins of which give rise to the concen-
tric lines so frequentlv seen in the scales
(PL 22. tigs. 6, 10, 22, 23, &c.). These lines
correspond to the margins of the layers, and
often present a nodular or crenate appear-
ance (fig. 116); and towards the middle
of the scales they are frequently interrupted
and irregularly curved (fig. lie). The sub-
stance of the upper portion appears to be
structureless.

In a transverse section, the projecting
margins of the laminae belonging to the
upper portion of the scale are seen as so
many teeth (PI. 22. fig. 12.)

INIany scales also exhibit radiating lines
(PL 22. fig. 23), corresponding to furrows
in the upper portion of the scales; these
are sometimes closed above, so as to form
tubes, and have been regarded as nutritive
canals.

Near the centre of some scales, as those
of the perch, are numerous rounded corpus-
cles or solid bodies, imbedded in the sub-
stance of the upper portion of the scales
(PL 22. figs. 6a & 7). At the posterior
portion of the same scales are often seen

SCALES.

[ r.77 ]

SCALES.

spine-like processes (figs. 0 h & 9), -with
rouuded or augidtir bodies, resembling the
last in appearance, arranged in rows at their
bases (tig. 8).

The scales of the eel appeal* to be princi-
pally composed of similar bodies, ditt'ering
only in form, and arranged in concentric
rows (PI. -22. figs. 20 & 20 a). They are
solid, impregnated throughont with calca-
reous matter, which is left after incinerating
the scales, retaining the original form of the
bodies (fig. 21).

In the scales of some fishes, particularly
those of extinct genera aiid species, lacuufe
and canaliculi resembling those of bone
(PI. 22. fig. 1 c), with Haversian canals, are
met with. A vitreous or enamel-like layer,
having the structure of dentine, is also met
with in the form of an external coating.

The structure of the spines or spine-like
scales of the skate is curious. The larger of
them consist of a button-like base, sur-
mounted by a sharp process (PI. 22. fig. 3).
The outer and lower part of the base is
opaque-white, and consists of an imperfectly
fibrous tissue with large areolfe (fig. 87j.
The spine is hollow, the cavity being con-
tinuous with that of a rouuded body, partly
immersed in the white substance (PI. 22.
fig. 3 a). The cavity is filled with a pulp,
consisting of lax areolar tissue with minute
cells; whilst its walls are composed of a
hard substance traversed by branched canals
resembling those of dentine (fig. 4). The
substance of the smaller spines (fig. 2)
exhibits the same dentine us structure
(fig. 5).

PI. 22. fig. 10 represents one of a longi-
tudinal row of scales extending along the
middle of the side of the body of most
fishes, and traversed by a tube (a), formerly
supposed to give exit to the mucous secre-
tion of the surface, which view has lately
been thrown into doubt. The tubes are
visible to the naked eye, and produce the
lateral line, as it is called.

The scales of fishes contain a large amount
of inorganic matter, composed principally of
phosphate of lime, but mixed with the car-
bonate. The organic basis consists of a
cartilaginous substance.

Some years since, Agassiz founded a
classification of fishes upon the structure of
the scales, having found that with difiTerences
in the scales other great and important di-
stinctions were in harmony. The system
has been found of eminent service to the
geologist: although later researches have

shown that scales presenting the charac-
teristics of those belonging to fishes of dif-
ferent orders in this system have been
found upon tlio same fish.

The arrangement was as follows : —

Scales enamoUed.

Ord. 1. Ganoid fishes. Those the skin
of which is regulai'ly covered with angular
thick scales, composed internally of bone,
and externally of enamel. Most of the
species are fossil, the sturgeon and bony
pike being recent.

Ord. 2. Placoid fishes. Skin covered iiTe-
gularly with large or small plates or points
of enamel. Includes all the cartilaginous
fi.she3 of Cuvier, except the sturgeon ; as
examples may be mentioned the sharks and
rays. Many are fossil.

Scales not enamelled.

Ord. 3. Ctenoid fishes. Scales horny or
bony, serrated or spinous at the posterior
margin. Contains the perch and many other
existing species, but few fossil.

Ord. 4. Cycloid fishes. Scales smooth,
horny or bony, entire at the posterior mar-
gin ; as the salmon, herring, roach, and
most of our edible and freshv^^ater fishes.

Most of the fossil fishes belong to the
first two orders, and most of the recent to
the third and fourth.

BiBL. Agassiz, Ann. So. Kat. 2. xiv. ;
Mandl, Ann. Sc. Nat. 2. xi., xii., xiii. & xiv. ;
Reade, Ann. N. H. 1838, ii. 191 ; Muller,
Wiegm. Archiv, 1843, 298; Vogt, Zooloq.
Brief e, ii. ; ^^^ilUamson, P/;//. Tr. 1849,435,
& 1851 ; Salbey, Struct, and Growth of
Scales of Fish, Ann. N. H. 1870, v. G7.

SCALES OF Insects. — The fine dust
which adheres so readily to the fingers on
handling a butterfly or moth consists of a
number of microscopic flattened bodies,
called scales or feathers, upon which the
beautiful coloiu-s and opacity of the wings
depend, the membranous wing itself being
transparent and colourless.

These scales have always been favourite
microscopic objects, both on account of the
beauty and variety of their forms, and the
curious markings found upon them. The
manner in which they are attached is be,st
examined in the wing of a butterfly. Each
has a narrow portion at its base, forming a
pedicle or stalk. ' The stalks are implanted
into small and short tubes or cups (PI. 34.
fig. 23 b), denominated the squamuliferous
tubes, the orifices of which are directed
backwards. Around the points of attach-
ment of the cups to the wings, the surface

SCALES.

[ 078 ]

SCALES.

exhibits a number of irregularly radiating
rugae or folds of the upper membrane of the
wing (PI. 34. fig. 26). The cups are arranged
in more or less regular transverse rows.
Each scale is composed of two superficial
laminje, enclosing a central lamina of struc-
tureless membrane, the surface of which is
highly polished.

The scales are variable in form, both in
different insects aiul in different parts of
the same insect, being oval, obloug, cordate,
obcordate, or cuneate, &c. (Pis. 1 & -M) ;
sometimes they are filiform or capillary
(Pi. 34. fig. 27). Their free end is rounded,
truncate, toothed, or terminated by a num-
ber of hair-like processes ; and they are ar-
ranged like the tiles of a roof, overlapping
each other (fig. 26).

The interesting markings seen upon the
scales vary considerably in different insects.

The most common, as seen by transmitted
light, are longitudinal, simple, continuous,
parallel or slightly radiating dark strife or
lines (PI. 1. figs. 6, 7, 8, 9 a). These are met
with upon the scales of nearly all butter-
flies and many other insects. Li some in-
sects the striae are not simple and conti-
nuous, but are made up of rows of smaller
striae in twos or threes meeting at an angle
(PL 34. figs. 28 b, 30 & 31). In others they
are composed of a mmiber of bead-like dots,
or are interrupted, still preserving their ge-
neral longitudinal direction (PI. 34. fig. 24) ;
or they are slightly undulate or irregular,
and give off" short lateral branches (figs. 23 a
& 29). In others, again, they present dila-
tations in certain parts of their course (figs.
20 & 21).

These longitudinal striae consist of eleva-
tions or ridges upon the sm-face, probably
representing folds of the upper layer or
membrane of the scale. They often project
slightly from the free end of the scale (PI.
34. figs. 3 & 22) ; and when moistened,
bubbles of air may not unfrequently be
found imprisoned between the surface of
the scale and the cover, which, being con-
fined between two of the ridges, assume an
oblong form. They sometimes contain air,
which may be displaced by liquid (PI. 34.
fig. 21). We have never been able to de-
tect trachea} in these folds or in the scales.
A minute conical point or spine sometimes
occurs in each of the dilatations when pre-
sent (fig. 20 a).

In the scales of Podura (PI. 1. fig. 12),
the striao consist of longitudinal rows of
minute vs^edge-shaped bodies.

In addition to the longitudinal striae, on
most scales, especially when examined by
unilateral oblique light, are seen a number of
minute transverse strife (PI. 1. figs. 7 & 9 «).
These are neither indications of ridges nor
depressions, but arise from the existence of
a number of pigment-granules situated be-
tween the two layers of the scale ; and the
appearance of striae has the same origin as
that in the case of the valves of the Diato-
maceae. This point is best examined in
brown or other dark-coloured scales. If
perfectly direct light be transmitted through
one of these scales, the transverse striae
vanish, their place being occupied by the
distinct and isolated granules of pigment
(PI. 1. fig. 9 b) ; the scale should also be
immersed in balsam or hquid, to diminish
the effects of the refraction arising from the
inequalities of the surface of the scale. On
then transmitting unilateral oblique light
through the scale, the appearance of trans-
verse striae may be easily produced.

The colours of the scales of insects arise
partly from iridescence, partly from the pre-
sence of pigment ; in general, the brilhant
colours depending upon tlie former, and the
more sombre hues upon the latter. The
darkness of the longitudinal striae is caused
by refraction ; for scales containing no pig-
ment appear perfectly white by reflected
light, although the strife may be very dark.

Upon certain scales, other irregular, more
or less transverse cm-ved striae exist (PI. 34,
figs. 3 & 22) ; thes'e appear to consist of
wrinklings or folds of the under membrane
of the scale.

In examining the scales of insects, they
should be viewed both in the dry state, and
immersed in water, or oil of turpentine;
and both by transmitted and reflected light.
When the insects are pressed against the
slide to remove the scales, a number of
globides of oil adhere simultaneously to the
slide ; and when the cover is applied, the
scales often become partially or entirely
covered with the oOy matter, producing an
appearance as if the upper layer of the scale
were removed, and rendering the markings
so pale and indistinct as to be apparently
absent. The appearance of transvei'se striae
is best produced by turning the mirror to
one side, so as to reflect unilateral light.

A brief notice of some interesting insects
in respect to the structm-e of. their scales is
given under the individual heads, as CuR-
cuLio, Lepisjia, Morpho, Poduba, Po-

LYOMMATUS, PONTIA, TlNBA, &C.

SCALES.

[ 679 ]

SCHTSTOSTEGE^.

See also Test-objects.

BiBL. West wood, Intr. ^-c, and Brit.
Butterflies; Descliamps, Ann. Sc. Nat. '2.
iii. Ill ; Diij. Ohs. au Micros. ; Ratzeburg,
Die Forst-Insekten ; Siebold, VergleicJi.
Anat. ; Pigott aud M'Intire, M. M. J. 1870,

o31 ; /6."1871, V. 3;

Watson,

ih. ii. 73

IV.

& 314; Anthony, ib. 1872, vii. 1 & 250
M'Intire, M. M. Jn. iii. 1 ; Maddox, M. M. J.
V. 33 ; Woodward, ih. v. 149 ; Beck, Qu. 31.
Jn. 1864, 2 ; Mn. Mic. Jn. iv. 2-52 ; Wonfor,
Qu. Mic. Jn. 1868, 80 ; Slack, Mn. Mic. Jn.
vii. 48 ; Pigott and Beaumont, Proc. Roy.
Sac. 1873, 222; Wenliam, Mn. Mic. Jn.
1874, 75; Woodward, ih. xv. 2">3.

SCALES OF Plants.— Under the head
of Hairs, mention has been made of scales
(lepidesj occurring on the epidermis of
plants. They consist of flat, usually more
or less circular plates of cellular tissue, the
cells presenting a radiated an'angemeut
from the centre, by which they are ordi-
narily attached ; the margins are usually
toothed or fringed more or less regularly by
the prolongation of the free ends of the
cells. They are closely related to stellate
hairs, such as those of ivy, of Deutzia (PI. 28.
figs. 26*, 27), &c., and may be regarded as
more highly developed forms of these. They
are particularly remarkable on the epidermis
of certain plants which exhibit a Mud of
scm'fy surface, for example
the Eleagnaceae (fig. 626),
the Bromeliaceas, some
Rhododeudra, aud the
lower surface of the leaves
of mauy ferns ; they must
be distinguished in the
last case from the ramenta
of the stems, which are ''■'.■\r'^%\
attached by the base, and scale of the epidermis
not by a central pedicle. of Hippophae rham-

BiBL. See HAIBSand ^°4^-fle, go diams.

Epidermis.

SCAPHID'IODON, Stein.— A genus of
Hvpotrichous Infusoria. Free, convex above,
flattened and ciliated below, pointed behind ;
mouth with a cylinder of teeth. <S'. navi-
cula; marine; length 1-240". (Kent, 7«/.
750.)

SCARID'IUM, Ehr.— A genus of Rota-
toria, of the family Hydatinaia.

Char. Eye single, cervical, rotatory organ
armed with a hooked bristle in front; foot
forked, very long, adapted for leaping.

Lateral processes of jaws bifurcate, so as
to present two teeth each.

S. lonyicaudum (PL 44. fig. 27). Foot as

Fig. 626.

ff?f^

^^

long as or longer than the body, toes shorter
than the foot; freshwater, length 1-72".

BiBL. Ehr. Infus. 439 ; Prit. Inf. 6SG.

SCENEDES'AlUS, Meyen.— A'genus of
Desmidiacea?.

Char. Cells fusiform or oblong, arranged
side by side in a single row of from two to
ten, after division forming two alternating
rows ; division oblique ; terminal cells often
lunate, or with a bristle at each end.

Several species (Ralfs).

S. quadricaucla (PI. 14. fig. 50). Cells
generally four, oblong, rounded at the ends,
in a single row, terminal cells with a bristle
at each end. Common ; length of cells
1-1120".

S. ohliqims (PI. 14. fig. 51.) Cells ellip-
tico-fusiform, after division aiTanged in two
distinct and generally oblique rows, end
cells lunate. Length 1-1670".

_ S. ohtusus (PL 14. figs. 53 & 54, just after
division). Cells three to eight, ovate or
oblong, all alike, arranged in one row, or
after division alternately in two rows. Com-
mon ; length 1-2330 to 1-1960".

BiBL. Ralfs, Brit. Besmid. p. 189.

SCEPTRONE'IS, Ehr.— A genus of
Diatomaceae. Frustules those of Syiiedra,
but the valves cuneiform. Several species,
marine and fossil. (Ehrenberg, Ber. Berl.
Ak. 1844,264; Grunow, 31. M. Jn. xviii.
169.)

SClIlS'MA. — A genus of Jungermannieas
(Hepaticae), founded on a rare British form,
*S'. {Jung.) juniperina, /3. europaa, found
among rocks on the mountains of Scotland,
Ireland, and Wales. It grows 3 to-6" high,
and is rarely found in fruit.

BiBL. Hook. Br. Fl. ii. pt. 1. 124, Br.
Jung. pi. 4 ; Ekart, Sgn. Jung. pi. 8. fig. 62 ;
Endlicher, Gen. Plant. Suppl. 1. No. 472.
17.

SCHISTOSTE'GE^.— A family of oper-
culate Acrocarpous(terminal-fiauted) Mosses
of gregarious habit. Stem naked below,
foliaceous in two manners above ; sometimes
frond-like or fern-like, composed of leaves
attached vertically and connected at the
base, with dense areolations consisting of
rhomboidal prosenchymatous pellucid or
green cells ; sometimes with small leaves,
like those of other Mosses, horizontal and
arranged quincuncially. All the leaves
nerveless and flat. Capsule without an
annulus, very minute, globular-oval, with a
very small convex operculum (figs. 627-
630). British genus :

ScHiSTOSTEGA. Calyptra cylindrically

SCmSTOSTEGE.E.

[ 6S0 ]

SCHIZOCIILAMYS.

bell-shaped. Inflorescence dioecious, plants
similar.

The only species of this genns, the elegant
little Sch. osmuiidacea, Web. and Mohr (JSch.

Fig. 627.

Scliistostega osmundacea.
Leaves of barren branches. Magnified 50 diameters.

pennata, Hook, and Taylor), occurs liere and
there in Great Britain. Tlie name was
derived from what appears to have been an
erroneous observation of Hedwig, who de-
scribed radiating fissures in the operculum,

Fig. 628.

Fig. 629.

Fig.

630.

Scliistostega osmundacea.

Fig. 628. A plant and fruit. Magnified 10 diameters.

Fig. 629. Open capsule with operculum. Magnified
50 diameters.

Fig. 630. Young capsule opened, showing the colu-
mella. Magnified 50 diameters.

Avhich do not exist in living specimens.
The germinating confervoid prothallium of
this moss was described by Bridel as an alga,
under the name of Catoptridium smarag-
dimim ; Agardh described it as a Protococcus
{smarcu/dhvis) ; and it was long supposed to
be phosphorescent : this appears to be an
error : iSchistosfega grows on the roofs of
sandy caves and similar places; and the

luminous appearance seems to arise from
the condensation and reflection of the little
daylight admitted, by the pellucid convex
cellules of the prothallium.

SOHIZ.E'A, Smith.— A genus of Schi-
zaeaceous Ferns, of curious and elegant struc-
ture ; several species; exotic (figs. 631,
632).

Fig. 681.

Fig. 632.

>-^

Schizsea dichotoma.
Fig. 631. A fertile pinna. Magnified 5 diameters.

A pinnule with sporanges. Magnified 2.5

Fig. 632.
diameters.

-An order of Polv-

SCHIZ.'EA'CEyE.-

podiaceous Ferns. .

Char. Sporangia 2-valved, opening down
the side, crowned by a complete operculiform
ring ; indusium none. Genera :

Schizcea. Sporangia sessile, in 2-4 rows,
covering one side of close distichous spikes,
w-hich form separate fertile segments at the
apex of the fronds.

Anemia. Sporangia small, very numerous,
forming a copiously branched panicle, di-
stinct from the leafy part of the frond.

Moliria. Sporangia sessile, on the bark
of the leafy frond, near the edge.

Trochopteris. Sporangia small, sessile,
placed irregularly round the edge on the
under side of the slightly contracted lower
lob(;s of the leafy frond.

Lijgodhtm. Sporangia solitary, or casually
in paii-s, in the axils of large imbricated
clasping involucres, which form spikes, either
in separate pinufc or in lax rows along the
edge of the leafv ones.

SCHIZOCH'LA]\IYS, Br.— A genus of
Palmellacese (Confervoid Algae). aS". gelati-

SCTITZOGONIUM.

[ (^81 ]

SCIIIZUMYCETES.

nosa (PI. 3. fig. 16) is found growing upon
aquatic plants or floating ii'ee,in little gela-
tinous masses composed of globular green
cells, 1-2000" in diameter, surrounded
by a hyaline cell-membrane. The i-emark-
able peculiarity in this genus is the splitting
of the hyaline membrane into two or four
equal pjii-ts by regular, clean dehiscence, the
internal cell-mass becoming divided at the
same time or remaining imchanged. By
frequent repetition of this splitting, the
internal cell acquu-ing anew coat each time,
the cell becomes surrounded by a number
of fragments of the old coats, held together
by a gelatinous matter.

Zoogonidia produced by the division and
subdivision of the cell-contents. Macro-
gonidia and micrngonidia exist.

BiBL. Braun, J^erjii)H/u)ig, Hai/ Soc. 18o3 ;
Klitz. Sp. Alg. 891 • Kabenh. Alg. iii. 32.

Fig. 633.

Schizogonium murale.
Filaments of frond in variouB stages of development.
Magnified 300 diameters.

SCHIZOGONIUM, Kiitz.— A genus of
Ulvacefe (Confervoid Algae), nearly related
to Prasiola, distinguished by fUiform fronds,
which, when young, present only a single
row of cells, but subsequently, by collateral
subdivision, have two, four, or eight parallel
rows. Of the species given by Kiitzing, the
following appear to be British :

S. murale {Bangia vehttina, Ktz., olim)
(fig. 633). Fronds of a single row of cells
1-2400 to 1-2100" in diam. ; double, 1-1440
to 1-1260" ; triple, 1-720"; cells half as long
as broad, dull gi-een. On damp earth and
walls, common.

S. ^je/r?»'S2<?/8 (HJnteromorphn, Ag.).
Frond with a double row of cells, 1-1200 to
1-900" in diam. ; length of cells equal to the
breadth ; bright or pale green ; collapsed
when dry. Marine.

S. Icetevirens (^Bcmgia, Ilarv.). Frond
with a simple row of ceils, 1-1800 to 1-1440"
in diam., rigid ; with a double row, 1-600' ' ;
bright or yellowish green. Marine.

Bangia lacustris, Harv., is given as a
doubtful species.

BiBL. Kiitz. SiJ. Ah/. 350, Tab. Phyc. ii.
pis. 98, 99 ; Harvey, Brit. Alg. 1. 172, and
Marine Alg. 211.

SCHIZOLO'MA, Gaudichaud, = Liml-
sai/a, pt.

'SCHIZOM'ERIS, Ktz.— A genus of Ul-
vaceae (Confervoid Algse).

Char. ThaUus capillary, flattened upwards,
fixed by a callous base ; growth by cell-
division, first in one and then in two direc-
tions, so as to form cell- groups of fours. S.
Leibleinii (PL 3. fig. 17) ^freshwater.

BiBL. Rabenh. Fl. Eur. Alg. iii. 311.

SCHIZOMYCE'TES, Nag.— An order of
Fungi.

These organisms consist of very minute,
mostly colourless cells, or filaments, occur-
ring in organic liquids, or upon organic bodies,
from which they derive their nourishment,
and the decomposition or putrefaction of
which they produce by their vegetative
growth. They are sometimes globular, at
others cylindrical, more or less distinctly
jointed, straight, undulate, or spiral. They
were formerly supposed to arise from spon-
taneous generation; also to be the early
forms of Mucedines kc, but their develop-
ment in this direction has not been traced.
Some are motionless, others move by cilia,
or internal undulatory motion. In some
cases, they secrete a gelatinous material,
which unites them into rounded masses,
constituting the so-called zooglcea-forms.
They are all insoluble in potash or ammonia.
They are reproduced by transverse division,
or by sporangia and spores; i. e. certain of
the cells or joints are more persistent, and
offer more resistance to outer agencies.

They are stated to cause phosphorescence
upon decomposing fish.

Tlie knowledge of these organisms is very

SCHIZONEMA.

[ 682 ]

SCHIZOXYLON.

incomplete, and it appears that mere pro-
ducts of decomposition of higher organized
bedies, and crystalline precipitates and crys-
talloids of carbonate of lime have been in-
eluded among them.

Some are recognized as the zymotic
agents in the production of disease, as Ty-
phus and Typhoid Fever, Splenic Fever, &c.
Five genera are admitted : Micrococcus, cells
globular, indefinite ; Sarcina, cells in cubes ;
Bactermm, cells or joints single or in twos,
short ; Spirillum, fibres undulate, short, in-
flexible ; SjnriUum, fibres spiral, flexible ;
Spirochete, fibres helical, long.

See the genera, and the Bibl. of those
articles.

SCHIZONE'MA, Ag.— A genus of Dia-
tomaceae.

Char. I'rustules short, straight or sigmoid,
resembling those of Navicula, aggregated in
longitudinal rows in a fihform, simple or
branched, slender and lax gelatinous frond.
Marine.

Sporangia or sporange-like bodies (sper-
matia) fiUed with frustules, occur within the
substance of the sheaths. This form of
brood-sporangia, as they might be called,
appears to resemble that occurring in the
Desmidiacea? (PI. 10. %. 3 A).

The species in which the frustules are
contained in simple tubes, form the genus
Colletonema ; those in which the tubes are
enclosed in outer tubes, the genus Micro-
mega (PL 17. fig. 8). Eabenhorst includes
all in the genus Schizonema.

Species very numerous ; Smith describes
seventeen as British.

8. Dillwi/nii (PI. 19. fig. 1 2) . Frond hya-
line, tufted, wavy, lubricous, bright green,
much branched ; end branches short, nume-
rous, patent, attenuate, and somewhat acute ;
frustules towards the base of the frond
remote and scattered, towards the ends
crowded, oblong-truncate in front view;
valves lanceolate, 1-1020'' in length.

Bibl. Kiitzing, Bacill 111, Sp. Ah/. 97 ;
Smith, £r. Diai. ii. 71 ; Eabenhorst, Aly.
i. 265.

SOIIIZONEU'RA, Hartig.— A genus of
Aphidae. (5 species, including^;)7j/.s lanif/era ;
on the apple, blaclf currant, fir, elm, pliun,
&c. (Buckton. Aphid., Ray Soe. iii. 88.)

SCIIIZOPIIYL'LUM, Fr.— A genus of
Agaricini, characterized by the gills splitting
along the edge and becoming re'\olute.

*S'. commtme is one of tbe commonest exotic
Fungi, and is rare in tliis country, except
introduced accidentally on foreign wood.

Bibl. Fr. Obs. i. 103 ; Sow. 1. 183 ; Grev.
t. 61 ; Berk. Eng. Fl. v. 130 ; Cooke, Handb.
16.

SO HIZOPOREL'L A, Hincks, = Lepralia
pt. Orifice of the cells semicircular or
rounded, inferior margin with a notch.
Several species. (Hincks, Polyzoa, i-il.)

SCHIZ'OPUS, Clap, and Lach.— A genus
of Hypotrichous Infusoria.

Char. Marginal cirri absent, frontal cirri
and uncini present, also dorsal styles. 1 sp.
S. norvegicus, (PI. 52. fig. 20) ; marine.
(Claparede et Lachmann, Inf. 182.)

SCHIZOSI'PHON, Kt.— Bodies as in
Slichofricha, but situated in the ends of a
branched zoary. S. socialis ; freshwater.
(Kent, Lif. 778.)

SCHIZOSI'PHON, Kiitz.— A genus of
Oscillatoriacefe (Confervoid Algae), contain-
ing Cttlothrix scopulorvm, fasciculata, and
perhaps other species of Harvey's 'Manual.'
Another British species has also been de-
scribed by Caspary, <S'. Warrenice (PI. 8.
fig. 13) ; this extends over large surfaces of
maritime rocks, in dull blackish-green tufts
of variable size, from 1-4 to 1-2" in thick-
ness. The ei'ect filaments are fastigiately
branched («), the basal cell of the branches
broader and hemispherical (c) ; ochreal
sheaths obscure (5), frequently exhibiting a
spiral-fibrous structure in decay (d, e) ; apices
of the branches much attenuated.

Bibl. Kiitz. Sp. Alg. 326, Tab. Phi/c. ii.
pi. 47 ; Harvey, Mar^ Alg. 224 ; Caspary,
Ann. N. H. 2. vi. 266, pi. 8 ; Eabenhorst,
Alg. ii. 232.

SCHIZOTHE'CA, Hincks, = Lepralia
pt. Two species. (Hincks, Polyzoa, 283.)

SCIH'ZOTHRIX, Kiitz.— A" genus of
Oscillatoriaceae (Confervoid Alga3),of which
two British species, growing over maritime
rocks, have been described.

S. Cresivellii (PI. 8. fig. 17). Tufts 1-2 to
3-4" high, olive-coloured ; filaments curled,
1-3000" in diameter at the base, 1-12000" at
the summit, in twisted bundles, peniciUately
corymbose above.

S. Smithii (Coleonema), Thw. Stratum
dense, dirtj^ red ; filaments closely entwined,
more or less laterally concreted, 1-9000 to
1-8400" in diameter ; sheaths lax, multipli-
cat4^, the internal prolonged and exserted.

Bibl. Kiitz. Sp. Ah/. 320, Tab. Phi/c. ii.
pi. 40 ; Ilarvev, Mar. Alg. 223, pi. 26 B,
Ph>/c. Brif. pi. "190.

SCHIZOX'YLON, Pers.— A genus of Pla-
codt'i (Liehenacoous Licliens). One species ;
on oaks, rare. (Leigh ton, Lich. Flora, 390.)

SCHULTZE'S FILMS.

[ 083 ]

SCLEROTIUM.

SCHULTZE'S FILMS. See Silica.

SCPIULTZE'S TEST.— This was origin-
ally proposed by Pettcnkofer as a test for
bile ; but Sclmltze found that it reacted also
witli several other substances, and especially
the proteiue compounds. In this application
it is often of use in discriminating one kind
of tissue or substance from anotlier. It con-
sists in treating the matter with strong sul-
phuric acid, and tlien adding a little syrup.
The characteristic reaction is the produc-
tion of a purplish-red colour. The best
method of proceeding is to wash the sub-
stance in question, then to moisten it with
a drop of syrup, and finally to add the acid.

The tissues and substances aflected by
it are muscidar tissue, both striated and
unstriated ; nerve-tubes and cells; the cor-
puscles of blood, pus, and mucus ; epithelial
and epidermic scales; hairs; feathers; horn ;
whalebone ; and the cellular portions (cell-
contents ?) of Fungi and Algae.

Those in which the reaction is not pro-
duced are areolar tissue, elastic tissue, gela-
tine and chondrine, chitine, silk, cellulose,
'gum, starch, and vegetable mucus.

BiBL. Schultze, Liehig's Annalen, 1849,
Chem. Gaz. viii. 98.

SCHULZE'S TEST.— This consists of a
solution of chloriodide of zinc, and is used as
a test for cellulose, which it colours blue.

The original directions given for its pre-
paration are indefinite ; they are as follows :
— dissolve zinc in muriatic acid, evaporate
the solution with excess of zinc until it ac-
quires the consistence of syrup, and dissolve
in this enough iodide of potassium to satu-
rate it ; iodine is then added, and the solu-
tion diluted with water if necessar3^

Radlkofer recommends zinc to be dis-
solved in muriatic acid, the solution to be
evaporated at a temperature but little above
that of boiling water, when a liquid of about
2-0 sp. gr. is obtained. This is diluted with
water until its sp. gr. is 1-8 ; if its original
sp. gr. was 2-0, 12 parts by weight of water
must be added to 100 parts of the solution.
In 100 parts of this liquid. 6 parts by weight
of iodide of potassium are to be dissolved at
a gentle heat, and the mixture heated with
excess of iodine until the latter is no longer
dissolved, and violet fumes become percep-
tible over the liquid.

This reagent has the consistence of strong
sulphuric acid, and is pale yellowish-brown.
It must be kept iu a well-stoppered bottle.

BiBL. ^&!iulze,i^/or«, 1850, 64.3; Schaclit,
Mikroskop. 30 & 197 ; Radlkofer, Liebi(j''s

Annakn, xciv. 332, Chevi. Oaz. 1855, xiii.
372.

SCIA'DIUxAI, Al. Braun.— A genus of
Unicellular Alga). The yovmg plant is
attached to foreign bodies, and consists of a
cylindrical cell («), in which arc produced
eight gonidia ; the top of the cylinder fall-
ing oft" lilco a cap, the gonidia emerge and
fiu-m an umbel of similar cylinders (b), the
bases of which stick iu the primary cell.
Each new cell repeats the process, so as to
forui a compound umbel ; but the gonidia
of the third generation (c) are set free, form-
ing the primary cells of new families.

S. arhuscula (PL 5. fig. 3); on freshwater
Confervoidea3 &c. Rabeuhorst unites this
genus with Ophiocytimn.

BiBL. Braun, Alff. Unieell. 48; Ciu-rey,
Mic. Jn. vi. 212 ; Rabeuhorst, Alg. iii. 66.

SCFRUS, Herm.,=5fMapt. ; including
the species with apparently a head and neck.
5 species, found among mosses, on insects, &c.
(Murray, Ec. Ent. 144).

SCLEREN'OHYMA. See Tissues,
Vkgetable.

SCLEROCHI'LUS, Sars.— One of the
Cytheridce, with smooth, hard, elongate,
bean-shaped valves ; lower antennae 5-
jointed ; upper 6-jointed, with long setse ;
eye single. One living British species ;
common. (Bradv, Linn, Tr. xxvi. 455.)

SCLERODER'MA, P. — A genus of
Trichogastrous Fungi having a firm peri-
dium, which bursts irregularly, containing
large granulated spores separated in masses
by Hoccose veins.

Four species have been found in this
country, one of which when young is sub-
stituted for truffles, though withont any of
the fine aroma.

BiBL. Fr. Syst. Myc. iii. 46 ; Berk. Outl.
t. 15. f. 4 ; Cooke, Hanclb. 374.

SCLEROT'ICA. See Eye (p. 310).

SCLERO'TIUM, Tode.— A large collec-
tion of fungoid structures were formerly
gathered together under this name, among
others the preparatory form of the Ergot
fungus. They are now all regarded as
consisting of the mi/celia of fungi in an
imperfect state. The sclerotioid state exists
when the mycelium forms hard tubercular
masses. Analogous -masses of mycelial
structures occur, in a pulpy condition, in
the Vinegar-plant ; in a filamentous con-
dition, in those fungi forming large masses
of barren bi/ssus, &c. ; in other cases, as in
some of the Myxogastres, the structure is
membranous.

SCOLIOPLEURA.

[ G84 ] SEBACEOUS FOLLICLES.

BiBL. Leveille, Ann. Sc. N. 2. xx. 218;
Berkeley, Hort. Jn. iii. 97 ; Fries, Su7n.
Veg. All.

SCOLIOPLEU'EA, Grunow.— A genus
of Diatoinacese. Frustules those of Na-
vicula or rinmdaria, with the median line
and hoop curved.

BiBL. Grunow, Wien. Verh. 18G0;
Rahenh. Alq. i. 228.

SCOLOP'EN'DRIUM, Smith, Tlares-
tongue. — A genus of Scolopendriese (Poly-
podiaceous Ferns), represented by the indi-
genous species Sc. vulgare (fig. 221, p. 319).

SCOLOPENDRIE'^. — A family of
Polypodiaceous Ferns ; containing the single
genus Scolopendvium.

SCRUPA'RIA, Hincks.— A genus of
Eucratiidfe (Polyzoa). »S'. clavata, on other
Polyzoa. (Hincks, Polyz. 21.)

SCRUPOCELLA'RiA, Van Beneden
{Cellularia, Johust., pt.). — A genus of Chei-
lostomatous Polyzoa, of the family Cellula-
riidse.

Char. Cells with a vibraculum behind,
and a sessile avicularium at the upper and
outer angle; orifice spinous. Five species.

S. scniposa. Cells without an operculum.
Common on Algfe, &c.

8. scrupea. Cells with a stalked reniform
operculum.

BiBL. Johnston, Br. Zooph. 3-36 ; Busk,
Ann. jV. H. 1851, vii. 83; Hincks, Polyz.
43.

SCUTELLID'IUM, Claus.— A genus of
Copepoda. 2 species, on Laminaria. (Brady,
Copep. ii. 175.)

SCUTOVER'TEX, Mich.— A genus of
Oribatidfe (Acarina), allied to Eremaius.
S. sculptiis, brown-black. (Michael, Jn. Mic.
Soc. 1879, ii. 241 ; 1880, 177.)

SCU'TULA, Tula-ne.— A genus of Coc-
cocarpese (Gymnocarpoua Lichens), para-
sitic, found upon Peltigera canina.

BiBL. Tulasne, Ann. Sc. Nat. 3. xvii. 118;
Lindsay, Qu. Mic. Jn. 1869, 140.

SCYPHID'IA, Duj.— A genus of Peri-
trichous Infusoria, family Vorticellina.

Char. Body oblong or campanulate, nar-
rowed at the base, which is very contractile,
covered with a reticular integument.

S. rugosa (PI. 31. tig. 74). Body with
oblique stripe or rugre, not numerous;
freshwater; length 1-550". Four other
species.

BiBL. Clap. & Each. //i/. 116; Kent, Inf.
658.

SCYP'IHUS, Koch.— A genus of Trom-
bidina (Acarina). S. diversicolor, very

minute, in damp moss, under decaying
leaves Sec.

SCYTO'MONAS, Stein.— A genus of
Flagellate Infusoria. Free, ovate, form
persistent, flagellum single, no mouth. S.
pusilla ; freshwater ; ' lengthl-1600" . (Kent,
Inf. 241.)

"SCYTONE'MA, Berk.— A genus of Os-
cillatoriaceae (Confervoid Algse), especially
distinguished by the mode of branching of
the filaments. We can only make out with
certainty one British species of the genus as
now restricted, <S'. Myochrous (PI. 8. fig. 19),
which grows in alpine bogs and rivulets,
and is composed of decumbent filaments
interwoven into a dark- brown stratum.

BiBL. Harvey, Br. Alg. 1. 155 ; Hassall,
Alg. 235, pi. 68 ; Kiitz. Sp. Alg. 303, Tab.
Phyc.

Fig. 634.

Gompound sebaceous eland, from the nose, opening
upon the surface with a hair-folliele. a, b, e, as in the
next figure; (i, lobules of the compound gland ; e, hair-
follicle (root-sheath) ; /, the hair.

Magnified 50 diameters.

SEBACEOUS FOLLICLESoR
GLANDS. — These organs exist pretty

SEBACEOUS FOLLICLES. [ G85 ] SEBACEOUS FOLLICLES.

generally in the skin, and secrete a fatty
matter. They are mostly seated close to
the hair-follicles, into which their ducts
usually opeu. They vary in form, some

Fig. 635.

Rimple sebaceous follicle, from the nose, a, glandular
epithelium, continuous with 6, the rete mucosum ; c,
contents of the gland, consisting of cells containing fat,
with free fatty matter.

Magniflod ,"0 diameters.

Fig. 636.

Glandular vesicle of a sebaceous eland, a, epithelium
continuous with the glandular cells b, containing lat.

Magnified 250 diameters.

Fig. 637.

Cells rem the glandular vesicles and the sebaceous
secretion, a, small nucleated cell, containing but little
fat, and resembling an epithelial cell ; b, cells abounding
in fat, without evident nuclei; c, cell in which the fat-
globules are becoming confluent; rf, cell containing a
single drop of fat ; e,/., cells from which part of the fat
has escaped.

Magnified .350 diameters.

being simple pouches or depressions of the
skin, whilst in others the deeper part of the
pouch is branched, so as to constitute a true
racemose gland. The narrower portion, or
duct, is variable in diameter ; it usually
opens into the hair-follicle, rather above its
middle, but sometimes upon the surface of
the skin itself.

Each gland consists of an outer coat of

more or less

connective tissue,

forming

thick membrane in proportion to the size of

Fig. 638.

ii.'--"?t..'

Development of the sebaceous follicles in a six-
months' foetus, a, hair ; b, inner root-sheath ; e, outer
root-sheath ; d, rudimentary follicle.

Magnified 250 diameters.

a, b, c, d, as above, but in a more advanced stage.
Magnified 250 diameters.

SECONDARY DEPOSITS. [ 686 ] SECONDARY DEPOSITS.

tlie gland ; this is derived either from the
hair-follicle or the cutis, according to the
situation ©f the gland. It is lined by layers
of roundish or polygonal, epidermic or
epithelial cells, the outermost of which
are closely connected, so as to form one or
more membranous layers, and contain few
or no globules of fat ; whilst the inner ones
are larger, and almost filled with these glo-
bules.

The development of the sebaceous glands
commences at the end of the fourth or in
the fifth mouth. The glands at first consist
of solid depressions or outgrowths of the
rete mucosum of the skin, or the inner
root-sheath of the hairs ; the inner cells
then become filled with fat, loosened, and
are finally evacuated through that part of
the immature gland which in its subsequent
development forms the duct.

BiBL. KoUiker, Mik. An. i. 180 ; Biesia-
decki, Strieker's Hist.

S E C O N D A R Y D E P 0 S I T S OB
LAYERS OF Vegetable Cells. — The
structures known by this name are spoken
of under Cells, in a general point of view,
and in detail under Pitted and Spiral
Structtjees. a few remarks maybe given
here, connecting the phenomena included
under the last two heads.

It is well known that the original or
2yritnarif cell-wall, the layer of cellulose by
which the cell first becomes really consti-
tuted as a closed membranous sac, is, so far
as our present instruments enable us to
judge, devoid of detailed structure : it is a
homogeneous pellicle. This has a power of
extension by interstitial nutrition, which
leaves no traces in the perfect membrane,
enabling the cell to increase in size. But
the increase in solidity is effected by a
different process, leaving distinct evidences
of its occurrence, namely by an application
of successive thin layers of cellulose mem-
brane, more or less completely all over the
inside of the primary membrane, giving the
cell-wall a laminated character, either evi-
dent in the natural condition, or capable of
being demonstrated by the aid of macera-
tion or corrosive applications.

No cell which is to form part of a ])erma-
neut tissut; remains long without receiving
secondary layers upon its walls. In certain
cases the wall (sxliibits in its natural state
merely the laminated htructure, withciut
any markings (PI. 47. fig. 24) ; but in the
majority of cases, where the secondary de-
posits are considerable, these layers exhibit

markings of very peculiar characters. As a
general rule, the layers present themselves
under two different types, according to the
extent to which they cover the primary
membrane. In one case they are applied as
a general layer over the wall, absent merely
at dot-like or slit-like points, where they
leave the primary wall uncovered, and thus
give rise to a pitted condition as seen from
the inside of the cell. Successive layers
lea^•iug the same spots bare, the pits become
gradually deeper, and form canals running
through the thick cell-wall to the primary
membrane (see Pitted Structures) (PI.
47. fig. 23).

Another curious condition of the secon-
dary deposits has been pointed out by Hartig
and Mohl, where large patches or spots upon
the cell-wall, especially at its base, are left
bare by the thicker secondary layers, and
become coated with a thin layer perforated
by minute orifices, as if riddled with holes,
or reticulated ; this is called a sieve-tube
or dathrate tissue.

In the other case, the secondary deposits
are more sparing in quantity, and are ap-
plied over lines forming a definite pattern
upon the primary membrane, in which a
spiral course in the direction of the long
axis of the cell is more or less evident ;
infinite modifications of this type occm*,
which are treated of under the head of
Spiral Structures (PI. 48. figs. 7, 9).

In certain less common cases we find the
earlier secondary layers exhibiting the pitted
character, while others later-formed produce
spiral-fibrous thickening, as in TaxHS, the
lime, and other cases (see Pitted Struc-
tures, PL 48. figs. 4, 13, 19 i).

The last-mentioned cases point to a rela-
tion between the spiral-fibrous and the
pitted layers, which appears really to exist,
for in a great number of cases it is possible
to distinguish a spiral structure in the
membranous layers of pitted cells, or even of
cells where the layers of thickening luerelv
exhibit the laminated structure without an}"-
pits or fibrous markings. Thus, in the liber-
cells of the Apocynace* (PI. 48. fig. 30),
the thickened walls appear under a low
power homogeneous, while under higher
magnifying-power, and especially bj^ the
help of acids, we may detect an evident
though delicate spiral structure. The action
of acids reveals a similar. sjiiral arrangement
of the constituent molecules, in the cotton
hair (PI. 28. tig. 1), and in most liber-cuUs
(figs. 2, 5, 25), in many wood-cells, as of

SECONDARY DEPOSITS. [ iif^T ] SECRETING ORGANS.

Pinus, &c. The membranes forming the
sheaths of many of the Oscillatoriacese
(PI. 8. figs. 13 d, e, 15) exhibit a spiral-
fibrous structure when undergoing dit^solu-
tion ; and an analogous condition may be
detected by the help of reagents pretty
generally in the cell-walls of the tubular
Confervse. AU these phenomena seem to
indicate a fundamental identity in secon-
dary layers of all kinds, to which we direct
attention under Spiral Structures ; but
it is convenient to keep the Pitted and
SpiRAL-tibrous structm-es distinct.

The mode of formation of the secondary
deposits is not clearly known : some imagine
them to be precipitated from the cell-sap
upon the waUs ; others, and apparently with
more reason, believe that they are attributable
to the agency of the primordial utricle,
continuing its action after the formation of
the primary membrane. Criiger goes so far
as to consider the spiral markings, &c. as
dependent on tlie RoTATiON-cuiTents of the
protoplasm. There can be little doubt of
the mistaken character of Trecul's view,
which regards the spiral and other fibrous
thickenings as folds of the primary wall
thrown inwards.

The secondary deposits appear to be always
composed of some modification of cellulose.
Mohl has investigated this point very
thoroughly ; and we have followed him over
much of the gromid. The cellulose, how-
ever, loses its distinctive character with
age, either by intilti-ation with foreign
matters, or by a slight chemical metamor-
phosis, so that old secondary layers do not
readily become blue when sulphuric acid
and iodine are applied ; but as a general
rule the cellulose reaction may be obtained
by using a preliminaiy treatment. AU in-
ternal structures, such as wood-cells, liber-
cells, stones of fruits, &c., should be boiled
in nitric acid, washed, dried, and tincture of
iodine applied ; then, if again dried and
wetted with water, they turn blue. Ex-
ternal structures, such as epidermal c.ells,
cork, and the like, require boiling with solu-
tion of potash.

Secondary deposits present considerable
di (Terence in their consistence and degree of
development in different cases. In most
wood- and liber-cells they are abundant in
quantity, in some cases almost filling up
the cavity (Pl. 47. fig. 27) ; here they are
hard, and appear to be in that state of the
cellulose-compound which may be distin-
guished as lignine. The same condition

prevails in the stones of fruits, bony shells,

the gritty tissue of pears, &c. ; and the less
abundant secondary substance of spiral-
fibrous tissues appears to be in the same
state. The secondary layers of parencliy-
matous cells are usually rather soft and
elastic, and often turn blue with sulphuric
acid and iodine alone ; those of the collen-
chymatous tissue beneath the epidermis of
many herbaceous plants, such as the Che-
nopodiacepe, &c., are abundant in quantity,
but of somewhat cartilaginous texture.
Those of the larger Algaj, and of the thallus
of the larger Lichens, approach to the same
condition, while the fleshy and horny al-
bumen of many seeds contains abimdant
deposits of analogous character (PI. 47.
figs. 21-2.3) ; in the latter the composition
is sometimes of amyloid, approaching starch,
stained blue by iodine alone, and more or
less soluble in dilute sulphuric acid. The
secondary layer of epidermis and corky layers
differs again, being usually more sparing in
quantity, but very firm and elastic, and
strongly resisting decomposing agents ; the
composition appears to be of that modifica-
tion of cellulose called sitherine.

BiBL. Mohl, Vegetable Cell, 1852, Bot.
Zeit. 1847, 97, Tat/lar^s Scientific Memoirs, 2.
i. 95 ; Schacht, PflanzenzeUe, 1852 ; Criiger,
Boi. Zeit. xiii. 1855, 601 ; Trecul, Ann. Sc.
Nat. 4. ii. 273 ; Wigand, Intercellular-sub-
stanzj 1850 ; Mulder, Phys. Chem. ; Henfi-ey-
Masters, Bot.

SECRETING ORGANS of Plants;
Reservoirs or Receptacles for Secre-
tions.— The structures falling under this
head have been in part treated of under the
heads of Glands and Laticiferous Tis-
sue ; but there still remain certain organs
of analogous character, which could not be
properly included under either of the above.
The name of receptacle or reservoir for
peculiar secretions is ordinarily applied to
groups of cells, of variable, but most fre-
quently elongated prismatic form, contain-
ing special secretions, either in their ca-
vities or eff'used into theu- intercellular
passages, traversing in the form of cords or
bundles the parenchymatous or prosenchy-
matous tissues. They are almost special
characteristics of families, and by no means
frequent; the Coniferte, the Cycadace9e,the
Alomeous Liliacese, the Polygouacese, Com-
positse, Umbelliferae, Amygdaleous Rosacese,
Leguminosge, &c. afford striking examples.

In the Coniferse the tm-pentkie-reservoirs
are very remarlcable ; and to a certain extent

SECTIONS.

688 ]

SEEDS.

they render it possible to determine the
genus by their arrangement. In Pimis they
consist of bundles of elongated thin-walled
cells, running through the wood parallel to
the axis of the stem. These thin-wall cells
are densely filled with turpentine ; in some
cases the cells of the meduDary ravs are
likewise filled with turpentine, and, besides
these, perpendicular intercellular passages ;
the latter form of turpentine-canal is chiefly
met with in the bark. Turpentine-canals
also exist in the leaves of the Coniferse, the
scales of the cones, &c.

The reservoirs of the Aloes are bundles
of prismatic cells accompanying the vascu-
lar bundles of the leaves and stems. The
colouring-matter of the root of rhubarb is
contained in cells of imperfect medullary
rays. The structure of the balsam-reser-
voirs of the myrrh tree, &c. has not been
thoroughly studied. The resin- and oil-
canals of the Umbellifer^ are of

great im-
portance ; but the former, chiefly occurring
in the roots, are imperfectly known. The
oil-ieservoir of the fruits (vitfes) consists of
elongated excavations in the cellular tissue,
filled with oil. Canals containing odorife-
rous oils occur in some of the Compositas.
Besin-canals occur also in the common lime.
Gum-canals, consisting of simple or
branched intercellular passages with a spe-
cial coat of small secreting cells, occm- in
the leaf-stalks of Cycadacese, the bark of
the Amygdaleee, the stems of the Malvaceae,
Cactaceae, &c. Structm-es of similar nature
contain the milky juices of certain plants, as
the Anacardiaceae ; and these appear to be
different from the ordinary Latex vessels.

BiBL. Meyen, Secret.-Organe d. Pflanzcn,
1837, 18 ; Unger, An. und Phys. der Pflcm-
zen, 1855, 204 ; v. Tieghem, An. Sc. Nat.
1872, xvi.; Sachs, JSoi. 79.

SECTIONS. See Preparation; and
for Schiefferdecker's section-cutter, Schidtze's
Arch. 1876, xii. 91 ; a modification. Kiddy,
Qu. Mic. Jn. 1877, xvii. 35 ; and Lewis,
M. M. Jn. xvii. 300.

SEEDS. — These are interesting objects j
for microscopic examination in respect to
many difiereut characteristics. Among ^
them may be mentioned first the variety of
beautiful markings upon the surface, which ;
render almost all saeds, like the elytra of j
beetles, interesting opaque objects for ob-
servation with a low power. A few striking {
forms are represented in Plate 89. figs. 14-
18 ; and we give a list of kinds easily to be j
obtained. ,

j Hypericum.
' Lychnis.

Stellaria.

Reseda.

Lepidium.

^'igella.

Erica.

Anayallis.

Orobanche.

Linaria.

CMronia.

Oentiana.

Datura.
Nicotiana.
Petimia.
Sedum.
Saxifraga.
Capparis.
Elatine.
Gesnera.
Begonia.
Delphinium.
Scrophularia.

Maurundya.

Sphenogyna.

Hyoscyamvs.

Setnpervivum.

Limnocharis.

Silene (PI. 39.

figs. 16, 17).
Dianthus (PI. 39.

fig. 15).
Papaver (PI. 39.

fi^. 14).

Antirrhinum. Digitalis (PI. 39,

Mesembryanthemum. fig. 18).

The following are well seen when mounted
as transparent objects in Canada balsam.

Parnassia.

Drosera.

Orchis.

Pyrola,

Monotropa.
Hydrangea,

Saxifraga.
Rhododendron .

j The testa or outer skin of some of the
latter (also Begonia), when removed from
j the seed and viewed with a high power, ex-
i hibits elegant pitted cells. The surface of
the seed of Cobcea is mealy with little scales
consisting of p^Tiform cells containino- a
spii-al fibre (PI. 28. fig. 20).

The surface of various seeds, such as Cnl-
lomia and Puellia, and the pericarp of many
seed-like fruits, such as that of Salvia and
Senecio, present remarkable Hairs.

The stones of plums or cherries, the so-
called shell of the Cocoa-nut and similar
fruits, exhibit remarkably thick Secondary

DEPOSITS.

The examination of the structure of ripe
seeds is a matter of great importance in
botany. The investigation will vaiy much
according to circumstances, ^^'here seeds
are large, the microscope is only required
for the examination of their tissues; but
small seeds must be examined by dissection
with needles under the simple microscope,
or by sections, which are most easily made
by fixing the softened seed into a piece of
wax. Seeds have two coats, the testa and
tegmen, or external and internal membrane,
and, according as the seed is or is not albu-
minous, an albumen enclosing the embiTO,
or an embryo of larger size immediately
invested by the coats. The characters of
the Albumen and Embryo will be foimd
under these heads, as also other particulars
under Ovule. Embryos are either Mono-
cotyledonous or Dicotyledonous ; sometimes,
however, the two cotyledons are soldered
together more or less completely. In the
Conifer?e and certain genera of Dicotyle-

SEIROSPORA.

[ 689 ]

SEPEDONIEI.

donous Angiosperms, as Schizopeta/mn, the
cotyledons appear to be four, six, or more
in uuniber ; but the observations of Du-
chartre show that there exist only- two —
bifid, trihd, or multitid cotyledons. In
other cases, as in Orchis, the embryo remains
imperfectly developed, and appears as a
mere cellular mass Lu the ripe seed before
germination ; this is destitute of albumen ;
but in Orohanchc an amorphous embryo is
found imbedded in the albumen.

BiBL. General icorks on Botany.

SEIROS'PORA, Harv.— A genus of Ce-
ramiacese (Florideous Algae), containing one
rare species, <S'. Griflifhsiana, a little crimson
feathery sea-weed, composed of single j ointed
tubes, the joints being traversed by articu-
lated filaments. The spores are unknown;
but the tctraspnres, which serve to distin-
guish this plant from the CaUithamnia, occur
in terminal beaded strings, being formed
out of the ramuli.

BiBL. Harvey, Mar. Alg. 170.

SE'JUS, lioc\i,= Gamams, pt. (Koch,
Uehers. 92 ; Murray, Ec. Ent. 164.)

SELAGINEL'LA, De Beauv.— A genus
of Lycopodiacese, distinguished from Lyco-
jjodimn by the presence of two kinds of
spores and the dissimilar habit.

This genns includes only one of our
native Club-mosses, *S'. sjnnosus {Lye. selayi-
noides) ; but most of the so-called Lycopodia,
now so extensively cultivated in Wavdian
cases, fern-houses, &c., belong to this divi-
sion (fig. 428, p. 481). The principal parti-
culars relating to these plants, especially
the remarkable history of the reproduction by
the spores, are given under Lycopodiace^.

BiBL. See Lycopodiaceje.

SELEiSITE.— This well-known mineral
substance consists of crystallized hydrated
sulphate of lime. Its crystals belong to the
oblique prismatic system ; and the colours
exhibited by thin laminse, into which they
may be easily split, are very beautiful under
polarized light. Polarizing crystals and
organic substances, in which the thickness
is not suited to the production of distinct
colours under the polariscope, may be made
to exhibit them by placing a plate of sele-
nite beneath the object. For this purpose,
the plate is usually kept mounted in Canada
balsam. See Polarization.

SELIGE'RIA, Br. & Sch.— A genus of
Leptotrichaceous Mos-^es, including certain
Weissice of authors ; having the leaves seta-
ceous, and the capsules pvrifoi-m.

SENBTNE'RA, Woods— A genus of

Jungermannieifi (Henaticae), mostly tropical ;
one species of wliich, «S'. {Jung. ) Wooddi,
occurs rarely in tlie mountains "of the S.W.
of Ireland (devoiil of fruit).

BiBL. Hook. Br. Fl. ii. pt. 1. 126; Br.

or seed-like fruits of the common groundsel
(Senecio vuJyaris) is sparingly clothed with
Haibs of a peculiar character. These ap-
pear to consist of two semicylindrical cells
apphed together by their flat faces, so as to
form a kind of tube with a vertical septum.
When placed in water they expand some-
what, and the contents are expelled from the
ends, consisting of an indistinctly spiral-
fibrous structure, which untwists and ex-
pands by the absorption of water, to twice
or three times the length of the hairs, in a
manner comparable in some degree to the
behaviour of the contents of the hairs of
Acanthace^. (Leighton, Ann. N. H. vi.
259.)

SEPEDONI'EL— A family of Hyphomy-
cetous Fungi, consisting of a heterogeneous
assemblage of imperfectly known genera-,
and difierently defined, by different authors.
Those genera we have included in our list
are enumerated in Liudley's ' Vegetable
Kingdom ; ' but Fries includes Oidinm and
others. The general character of the family
is, that the plants produce spores lying im-
mediately upon the decumbent filaments
of the mycelium, or upon short pedicels.
Genera :

Artotrogus. Entophytic; filaments creep-
ing, persistent; spores springing from tlie
middle of the filaments, simple, at length free,
spinous.

Sepedonium. Filaments woolly, septate,
evanescent; spores globose, connate, scabrous,
stalked, solitary, at length heaped together.

Fusisporium. Spores fusiform or cylin-
drical, glued together in heaps resting on the
gelatinous matrix.

Epochnium. Spores heaped, oblong, api-
culate, septate, adnate to the matrix, inter-
woven with the effused, entangled, slender
filaments of the mycelium.

Fsilonia. Spores simple, pellucid, not
glued together, at fi^st covered by the con-
verging filaments of the mycelium.

Monotospora. Epiphytic ; filaments creep-
ing, evanescent ; spores globose, solitary,
terminal, at length free.

Asferophorn. I'ilament' creeping, ramuli
branched, the fertile termiualing in a spiral

2y

SEPEUONIUM.

[ 690 ]

SERTULARIID^E.

coil, composed of about 3 joints, one of
which swells into a rough-coated spore.

Zyyodesmus. Filamentscreeping, branched,
■v^-ith short ramulibeaiing echiuate spores, the
pedicels with a lateral indentation looking
like a joint.

SEPEDO'NIUM, Link.— A genus of Se-
pedoniei (Hyphomvcetous Fungi), contain-
ing two species, growing upon decaying
Fungi. S. chrysospenna has golden-yellow
spores, S. roseum red ones. The first is
common. The species are all forms of
Sphferiacei.

BiBL. Berk. Br. Fl. ii. pt. 2. 350 ; Fries,
Sum. Vey. 497 ; Grev. Crypt. Flor. pi. 198.

SEPIA, Linn. — A genus of Cephalopoda.
The structure of the dorsal internal shell of
S. officinalis, the cuttle-fi^h, called the cuttle-
bone or sepiostaire, presents a curious struc-
ture. It is oval, flat, convex, horny outside,
the interior being calcareous and composed
of numerous friable, horizontal, parallel, cal-
careous plates, separated by innumerable
minute perpendicular flattened columns,
with transverse thickenings at pretty regular
intervals, producing a striated appearance.
When mounted in balsam, it forms an in-
teresting polarizing object.

SEPTONE'MA, Corda.— A genus of To-
rulacei (Coniomycetous Fun-
gi), related to Tom la, and
connecting this in some mea-
sure with Dendryphium. S.
spiloma, forming gi-een tufts
on old rails, has been found
in Guernsey. Several spe-
cies are recorded as French
by Leveille, one forming
patches on vine-leaves, the
others on the potato. The
chains of septate spores soon
break up.

BiBL. Corda, Ic. i. & ii. ;
Fries, Stim. Vey. 504 ; Le-
veille, Ann. Sc. Nat. 3. ix.
261 ; Berkeley and Broome,

Ann. N. H. 2. v. 461 ; Berk. Septonema viride.

Fig. 640.

Lond. J. Bot. iv. t. 12. fig. 5.
SEPTO'RIA, Fr.— A ^e-

Magnified 150
diameters.

nus of Sphaeronemei ( Coniomycetous Fungi),
but probably in reality consisting of pre-
paratory forms of Sphcerife. They grow
upon the leaves of plants, the fusifoim sep-
tate or inarticulate thread-like " spores "
oozing out from a pore in the form of a
tendril.

<S'. Ulmi and <S'. OxyacanthfP are common;
numerous other species ai'e recorded.

BiBL. Berk. Br. Fl. ii. pt. 2. 356; Berk,
and Br. Ann. N. H. 2. v. 379, xiii. 460 ;
Tulasne, Ann. X. H. 2. viii. 117, 4. v. 115.

SEPTOSPO'EIUM. See Macrospo-

HIUM.

SERIALA'RIA, Lamarck. — A genus of
Vesiculariidse (Polyzoa). *S'. lendiyera, the
only British species, is not uncommon on
Fuci, near low-water mark. (Ilincks, Polyz.
515.)

SEROUS MEMBRANES.— These con-
sist of the same elements, an-anged in the
same number of layers as in the Mrcous
Membranes. The thickness of the layers,
however, is considerably less, the fibrous
elements are finer, and the epithelium forms
a single layer only of polygonal cells. The
communication of the lymphatics with the
so-called stomata is noticed at p. 485.

BiBL. That of Tissues, Animal.

SERRA'TOR, Megnin. See Acarls,
p. 5 (Megnin, Paras. 144).

SERTULAREL'LA, Gray.— A genus of
Sertulariidfe (Hydroid Zoophytes).

Char. Cells biserial, alternate, with a
toothed orifice and an operculum composed
of several pieces. -S'. riiyosa (formevlj- Ser-
tuhiria ?•., PL 41. figs. 11 & 12); common
upon Flusf.rfe, Fuci, &.c. at low-water mark.
(Hincks, Br. Hydr. 234.)

SERTULA'RIA, Linn.— A genus of Hy-
di'oid Zoophytes, family Sertidariidaj.

Char. Polypidom plant-like, fixed by its
base, variously branched, the branches
formed of a single tube, denticulated or ser-
rated with the cells, and jointed; cells alter-
nate, semialternate, or opposite, biserial,
sessile, urceolate, with everted apertures ;
ovarian vesicles scattered.

Many of these elegant zoophytes, which
would at once be referred to the vegetable
kingdom by any casual observer, are com-
monly found on the sea-coast, either loose
or attached to shells, sea-weeds, &c.

S.jmmila (PI. 41. figs. 13 & 14). Cells
opposite, approximate, shortly tubular, the
top everted, with an oblique somewhat mu-
cronate aperture ; vesicles ovate ; common
on Fuci near low-water mark.

S. operculata (PL 41. figs. 15 & 16). Cells
opposite, inversely conical ; aperture patu-
lous; obliquely truncate, pointed on the
outer edge, and with two small lateral
teeth ; vesicles obovate.

BiBL. Johnston, Brit. Zoophytes, 61 ;
Hincks, Hi/dr. Zooph. 250.

SERTULARITD^E.— A famUy of Hy-
droid Zoophytes.

SETOSELLA.

691 ]

SHELL.

Char. Capsules quite sessile on a liovny

Solypidom ; egfi-frerm.s contained in scattered
eciduous capsules. British genera :
Hakcium. Polypidoni plant-like ; stem
consistinpf of several parallel tubes ; cells
shallow cups, on opposite sides, alternate,
one under each joint.

Sertularia. Plant-like ; stem simply tu-
bular, branched, jointed; cells vase-like,
alternate or in pairs, ou opposite sides, with
everted rims.

Reticularia. Polypidom an investinof net-
work of horny tubes, immersed in a homo-
geneous horny crust; cells short curved
projections of the tubes, with simple round
orihces.

Coppinia. Parasitic, massive, hairy ; cells
long, tubular, often curved, arising at irre-
gular distances (generally at the angles of
junction) out of a cellular basis, the aper-
tures of the cells or spores of which are often
themselves covered in by a lid perforated
by a small tubular orifice.

Thuiaria. As SerUdaria, but the cells
closely pressed to or imbedded in the surface
of the stem and branches.

Antenmdaria. Simple or branched, jointed,
with slender hair-like whorled branchlets ;
cells small cups on the inner side of the
branchlets ; egg-vesicles seated in the angles.
Phunidaria. Simple or branched, feathery ;
cells small, usually in the angles formed hy
horny spines on the inner side of thebranches;
egg-vesicles scattered.

BiBL. Hincks, Hi/dr. Zooph. 233.
SETOSEL'LA, Hks.— A genus of Poly-
zoa = Membrampora pt. aS'. vuhieraia, on
very small stones in deep water. (Hincks,
Polyz. 181.)

SHEEP-TICK. See Melophila.
A species of Trkhodect€s{sphceroeephalus)
is also found as a louse upon sheep.

SHELL OF Animals. — In this article
we shall notice the various substances com-
prised under the term shell, in its common
acceptation. See PI. 45. figs. 1-16.

Egg-shell. — As an example of the struc-
ture of the egg-shell of birds, we may select
the shell of the e<^^ of the coiLmon fowl.

This is lined internallj- by a loosely ad-
herent layer of a thin yet firm albuminous
membrane, called the membrana putaminis.
It consists of a number of very slender
fibres, interlacing in various directions. In
imperfectly formed or soft eggs, as they are
called, the fibres present thickenings at irre-
gular intervals, resembling, ou the whole,
the nuclear fibres of elastic tissue with the

remains of their formative cells still visible.
On macerating the shell in dilute nuuiatic
acid, an outer layav of this membrane, in-
separably adherent in the natural state to
the inner surface of the shell, may be
detached.

The membrane may be heated to boiling
in solution of potash without undergoing
solution, and is insoluble in acetic acid ; but
it is coloured by Schultze's test.

The substance of the shell consists of nu-
merous masses of secretion, or protoplasts,
impregnated with calcareous matter. In
soft eggs, these form rounded, loosely ad-
herent masses (PL 45. fig. 12), may easily be
detached from the surface of the eg^^, and
contain but little calcareous matter; whilst
in the perfect egg they are somewhat angu-
lar from mutual pressure, and abound in
calcareous granules having an imperfectly
radiating arrangement (PI. 4o. tig. 13j ; this
is most easily perceived in the inner por-
tions of the shell.

The structure of the shell of the ostrich
presents a curious variety. In a section
parallel to the surface (PI. 45. fig. 14) the
protoplast structm-e is visible, but the cal-
careous matter is arranged in the form of
triangular plates, often fused together, and
leaving angular interspaces. The perpen-
dicular section is represented in PL 45.
fig. 15. The former section constitutes an
interesting polarizing object.

Tortoise-shell. — This substance is an epi-
dermic formation, structurally resembling
horn, in so far as it consists of epidermic
cells flattened and united into numeroiis
superimposed plates. The long-continued
action of solution of potash (from twenty-
four to fortj-eight hours), and the subse-
quent addition of water, are necessary to
resolve tortoise-shell into its component
cells.

Shells of the Mollusca. — The structure of
these shells vaiies in the diftereut orders,
«S:c. of the class ; and a knowledge of the
respective varieties has been used as an aid
to the recognition of fossils, and the de-
teimination of the affinities of the genera,
families, &c.

In the bivalve Mollusca, two kinds of
structure may be distinguished, an outer
prismatic or fibrous, and an inner lami-
nated.

The outer prismatic portion consists of
flattened masses or plates of crowded poly-
gonal prisms, placed sometimes jerpendi-
cularlv, sometimes obliquelv to the surface

'2y 2

SHELL.

[ 692 ]

SHELL.

of the inner layer. These prisms are trans-
parent, and polarize light, possessing a crys-
talline structure, although their forms are
not crystalline but those resulting from
mutual pressure. Transverse sections of
the prismatic structure exhibit a cellular
appoarance (PI. 45. ligs. 4 & 11 a) ; and a
somewhat similar appearance is presented
by perpendicular sections (figs. 5 and 11 b).
The prisms are pretty easily separable in
the lines of mutual contact, and often form
several superimposed strata. They fre-
quently contain pigment, either uniformly
diffused through their substance, or in gra-
nules. They also sometimes appear trans-
versely striated.

The inner laminated portion, which some-
times constitutes the entire shell, is either
white or presents the brilliant iridescent
tints of nacre or mother-of-pearl. It is
often called the nacreous portion, or nacre,
and when polished forms the mother-of-
peavl of the shops. Under the microscope
it exhibits a number of tine lines or grooves,
running in various directions, and probably
ct)rresponding to the edges or intersections
of the strata or laminae of which this por-
tion of the shell is composed ; and it is to
the interference of light ensuing at the sur-
faces of these grooves that the iridescent
colours are usually owing.

In some shells {Terebratulce) there are
tubes traversing the substance perpendicu-
larly (PL 45. hg. 7) or obliquely, or forming
branched horizontal channels (fig. 9 a, b) ;
in the latter case they are sometimes con-
nected with rounded cavities (fig. 9 a).

In some Gasteropoda, as Cyprcea, the
outer portion of the shell consists of three
layers of similar prismatic structure, but
with the prisms in each layer in alternately
contrary directions. The same may be seen
in some of the outer layers of oyster-shell,
except that the prisms are nearly horizontal
or slightly oblique. But in the Acephala
generally,' the structure corresponds to the
inner portion of that of the Cephalophora.

Shell consists of an organic basis, in which
calcareous matter, principally composed of
carbonate of lime, is deposited; and by
digesting it with dilute muriatic acid, the
latter may be removed, an organic cast of
the original being left. On treating a thin
plate of nacre in this way, Carpenter found
that the iridescent colours remained visible
until the membrane was stretched and the
supposed folds obliterated, when they va-
nished j luuce this author concludes that

the edges of the folds were the cause of the
interference of light producing the colours.
It appears to us, however, objectionable to
this view, that the same structure and
colour are produced by laminated calcareous
and organic matter artificially formed ; that
they are also present after the edges of the
folds must have been ground away, as in
sections; and that the colours, in the in-
stance mentioned, might have been those of
a thin plate, and some of the colours of
iridescent shell are known to be those of
thin plates. It may be stated here that
Carpenter considers the lines or striae in
nacre to be produced by the edges of folds
of a single layer of membrane, arranged so
as to lie over each other in an imbricated
manner. The same author views the shell
of the Mollusca as corresponding to the
epidermis of the higher animals, calcified.

The outer prismatic layers of shell are
secreted by the borders or margins of the
mantle, whilst the inner laminated portions
arise from the outer surface. The growth
of shell is not uninterrupted or constant, but
periodical ; hence the laminated arrange-
ment of its constituents.

In some portions of the shell of the
oyster, &c., tlie calcareous matter assumes
the form of distinct rhomboidal or hexago-
nal crystals (PI. 45. fig. 10). These appear
to be deposited in the inner laminated por-
tion ; and when detached they leave angular
spaces corresponding to them in form. In
the tooth of the shell of Mija, groups of
radiating prisms are present, forming an
elegant microscopic object.

The prisms existing in the outer portion
of shells have been supposed to represent
cells filled v^nth calcareous matter; they
have also been regarded as consisting of
aggregations of epidermic cells, the trans-
verse striae (in Pinna) corresponding to
thickenings of the cell-membranes where
the layers come into contact ; and the folded
membrane has been compared to a basement
membrane. It is probable, however, that
shell should be regarded as a simple secre-
tion from the mantle, and as coiTespoudin»
m structure to egg-shell.

SheU of the Crustacea. — The hard portion
of the integument of the Crustacea, alkided
to at p. 215, possesses a laminated struc-
ture, corresponding to periods of growth,
and giving rise to the appearance of trans-
verse parallel lines in a perpendicular section
(PI. 45. fig. 16). The substance is traversed
by numerous straight, or slightly wavy,

SIAGONTIIEKIUM.

[ 693 ]

SILICA.

very slender tubes (PI. 45. fig. 16), resem-
bling' those of tlentine.

Shell of Ec/iiiioderinafa. — The perforated
structure of the homogreneous basis forming
this substance has been already noticed
(p. 274). In the spines of Echinus, Cidaris,
&c., the calcareous network consists of
slender tibres with large areolae at intervals,
arranged in a somewhat regular pattern, and
traversing a solid homogeneous substance,
which is thus divided into a number of ribs
or pillars. The transverse section of these
is seen in PL 45. figs. 6 & 6rt.

Carpenter regards the c ileareous network
as corresponding to the fibrous structure of
the cutis of the higher animals, calcified.
This view does not, however, account for
the intervening substance.

The method of procuring sections of shell
is noticed under Preparation.

BiBL. Carpenter, Tr. Brit. Association,
1844 oc 1847 ; Ann. X. H. 1843, xii. 376 ;
Gray, Phil. Tr. 1833 ; Deshayes, Todd's
Cycl. An. ^c. iv. 556 j Bowerbank, Tr.
Micr. Soc. 1844, i. ; Lavalle, Ann. Sc. Nat.
3. vii. ; Siebold, Verql. An. ; Brewster,
Phil. Tr. 1814, and Optics, 1853; Wood-
ward, Shells ; Williamson, Qu. Mic. Jn. viii.
35 ; Carpenter, The Microscope, 1881, 666.

SIAGONTHERIUM, Perty.— A genus
of Enchelia. Body ovate, very minute,
colourless, with an antero-lateral tuft of
reflexed ciha. S. tenue, in bog-water.
(Perty, Lif. 150.)

SI'DA, Baird {Daphnia, anct.). — A genus
of Entomostra'ia, of the order Cladocera,
and family Daphuiidge.

Char. Anterior branch of inferior an-
tennae two-jointed, posterior three-jointed
and with a row of spines at its .anterior
margin ; legs six pairs.

S. crystallina (PI. 19. fig. 27). The only
species; freshwater.

Daphnella belongs here.
BtBL. Baird, Brit. Entom. 107.
SIUEROLI'NA, Lamk.— Another name
for Caxcarina. (Carpenter, For. 199,
223.)

SIDY'NUM, Sav.— A genus of Tunicate
MoUusca, of the family Botryllid^.

S. turhinatmn. Amber or orange. On
the underside of shelving rocks. (Forbes
and Hanlev, Br. Moll. i. 13.)

SIEVE-T LJBES.— These are thin-walled,
elongated cells, united end-to-end in rows,
the intervening transverse portions, or bases
of the cells, forming perforated sieve-like
plates ; the sides next other sieve-tubes are

also sometimes perforated. The protoplasm
of tlie cells pass s through these perfora-
tions, forming minute fibres.

Sieve-tubes are found in the liljer of
Dicotyledons, and in the fibro-vascular
bundles of Endogens. They may be most
easily obtained from the stems or leaf-stalka
of Cucurhita pepo, Calamus Rofamj, Pota-
mo()ef.on nutans, Bi(jnoniu speciosu, Vitis
vinifera, &c. Sachs recommends that their
longitudinal sections be treated with so-
lution of iodine until the cell-contents are
rendered brown, and the subsequent addition
of sulphuric acid; this dissolves the cell-
wall and sieve-plates, allowing the slender
protoplasmic filaments to be distinctly seen.

BiBL. Sachs, Bot. 89 ; Ilenfrey-Masters,
Bot. 4S7; Wilhelm, Bot. Centralblatt, i.
908, Jn. Micr. Soc. 1881, i. 72.

SILICA. — This inorganic substance is
most abundantly met with in the mineral
kingdom, in the form of earth, sand, or di-
stinct crystals. The crystals belong to the
rhombohedral system, usually forming six-
sided prisms, terminated hj six-sided pyra-
mids. The mineral fornix are noticed under
Agate, including chalcedony, and under
Rocks.

In the animal kingdom, it is met with
especially in the Protozoa, forming the
spicula and elegant siliceous shells so
well-known as microscopic objects, and
which are noticed under the heads of the
classes, genera, &c.

In the vegetable kingdom, silica is a con-
stant constituent of the epidermis of the
Graminaceae, the Equisetaceae, and certain
Algae, especially the valves of the Diato-
maceae.

Chemically it is distinguished by its inso-
lubihty in boiling nitric acid, and its inde-
structibility by a red heat.

If, as Schultze fir.-t pointed out, some
sulphuric acid be added to a mixture of
powdered fluor-spar and sand, in a wide-
mouthed flask, with a short tube of mois-
tened blotting-paper in the neck, the fluo-
ride of siJiciimi, which is evolved, is decom-
posed, and silica is deposited in Alms upon
the paper. If these are washed in distilled
water, dried, and examined under the mi-
croscope, they are found to consist of
minute crystalloid "hemispheres of silica,
often pointed, and grouped into plates. The
finer ones present considerable resemblance
to the markings of the finer valves of the
Diatomaceae, when so minute as to be only
visible by their lenticular foci or their dif-

SILK.

[ 694 ]

SIPHONACE^.

fractinu-spectra, whence they were con-
sidered to represent and explain the forma-
tion of the siliceous structure of the valves,
and have heen called Schultze's iilms. The
coarser ones have no re.^emblance whatever
to the coarser marldugs of the Diatomacese.
Their relation to the valves of the Diato-
macefe has been referred to under Diato-

MACKiE.

SiUca has but little action upon pola-
rized light; in fact, Scliultze states that the
apparent depolarization is due to refraction.
The selenite-plate will, however, render it
more evident in many instances in which
it is feeble.

BiBL. Works on Chemistry; andSchultze,
Verh. Natnrh. Vereins. jy^-eiiss. Rheinlande,
XX. 1, Qu. 3Iic. Jn. 1863, iii.

SILK. — This valuable substance is se-
creted in Insects, especially the silkworm,
by two glandular organs, described under
Insects, Sphining Ovf/ans.

The fibres of which it is composed are
cylindrical or somewhat flattened, solid,
tolerably highly refractive, and free from
structural markings of any kind.

Chemicilly, silk consists of a proper silk-
cylmder, consisting of fibroine and forming
the principal part of the fibres, sun-ouuded
by a coat of albumen, upon which is a layer
of gelatine. The fibres also contain a small
quantity of fat and colouring-matter.

Fibres of silk may easily be distinguished
from those of linen or cotton by the appli-
cation of Millon's or Schultze's test, both of
which colour the silk, but neither of them
the linen or cotton. The test for cellulose
is equallv applicable to the same pvu-pose.

SIMULTANEOUS BUNDLES. See
Vascular Tissue.

SIPHOCORY'NE, Buckt.— A genus of
Aphida?. CBuckton, Aj)hid. ii.)

SIPHONA'CE^.— A family of Confer-
void Algse, either marine, freshwater, or
growing on damp ground ; characterized by
the individual fronds being composed of
large branched cells, the contents of which
expelled in various forms serve for the
reproduction. The fronds mostly have a
more or less compound character, either
from regular ramification, or b}' a kind of
stoloniferous multiplication at the base of
the cells; and in Hiffh-odicfj/on, which seems
best placed in this family, the cells are
always connected together by their extre-
mities, so as to form a net-like frond. In
the majority of the genera the cell-contents
are green. The modes of reproduction

exhibit considerable diversity, and are pro-
bably still imperfectly known in most of the
genei'a. Codimn and Bryopsis are repro-
duced by the discharge of the contents of
certain cells in the form of numerous small
ciliated zoospores. Vauc/ieria is increased
by large elliptical solitary zoospores, covered
with vibratile cilia ; in Hydrodictyon the
cell-contents are converted into a multitude
of cihated zoospores, which vuiite to form a
new net or fi'ond before leaving the parent
cell ; while in Botrydium the cell-contents
are said to he discharged in the condition
of motionless gonidia ; but we imagine this
point is not quite certain. In addition to
the gonidial reproduction, spores have been
discovered in Vaucheria, and will probably
be found in the rest. In Vaucheria they
occm- in special branch-ceUs ; here, however,
accompanied by antheridial cells, which pro-
duce spermatozoids, fertilizing the sporan-
gial cell. Spores have not yet been ob-
served in the other genera; but it is to be
expected that they will be found in them
also. More particular details on the very
interesting genera of this somewhat hetero-
geneous family will be found under their
respective heads. British genera :

Codium. Filaments green, branched,
closely interwoven into a spongiform frond,
producing biciliated zoospores in sporangial
cells borne on the sides of the erect clavate
branches ; marine.

Bryopsis. Filaments gi'een, free, pin-
nately branched, .producing two- or fnur-
ciliated zoospores in the extremities of the
branches ; marine.

Vaucheria. Filaments green, more or
less branched, continuous, producing in
their apices large solitary zoospores covered
with cilia ; also bearing lateral globose spo-
rangial cells and hook-like antheridial cells
or horns; marine or fi-eshwater, and still
more commonly on muddy ground, damp
garden- pots, &c.

Bofryditim. Frond a spherical green
vesicle seated on a ramified filamentous
base, the cavity of the whole continuous;
the ramified base producing new vesicles,
sporanges, by stoloniferous growth. Mul-
tiplied by the granular contents of the Aesi-
cle discharged by a rupture at the summit.
On damp, mostly clayey gi'ound subject to
floods.

Ilydrodicfynn. Frond a green bag-like
net, with usually pentngonal open meshes,
formed of cylindrical cells connected bv
their ends. Reproduced by ciliated zoo-

SIPIIONINA.

[ 695 ]

SKIN

spores formed in the " link "-cells, uniting
together and forming a perfect miniature
uet before escaping from the parent cell.

See also Pvthium.

SIPHONI'NA, Reuss.— A low form of
Planorhulina, having open-mouthed tubes
leading otl" the psondopods from the chani-
ber.'^, and large-necked septal oriiices. Re-
cent and fossil in the Mediterranean area.
(Parker and Jones, Ann. N. H. 3. xi. 94.)

SIPHOXOPH'ORA, Koch.— A genus of
Aphidae. Species numerous, on a variety of
plantvS. S. ros(e= Aphis i: (Buckton, ^4«/i«-
dce, i. 104.)

SIPHONOPH'ORA.— An Order of Hy-
dro-medusse ; the oceanic Ilydrozoa. (Hux-
lev, Phil. Tr. 1849.)

SIPHONOS'TOMA (Parasita, orPoecilo-
poda). — An Order of Crustacea.

Char. Body often almost entirely enclosed
in a buckler, consisting generally of one,
sometimes of two pieces ; mouth suctorial ;
legs formed for walking or prehension, or
partly branchiferous and fitted for swim-
ming. Parasitic upon fishes, &c.

Tliese animals (PI. 19. figs. 7, 23, 24, 36,
and PI. 20. fig. 1), which often present the
most extraordinary forms, are found mostly
affixed to the gills of fishes by means of
hooks, arms, or suckers, arising from or
consisting of modified foot-jaws. In some,
the cephalothorax is distinct from the abdo-
men, and the head is more or less distinct
from the thorax ; whilst in others the body
presents more of a worm-like form, is occa-
sionally ringed or segmented, and sometimes
exhibits simple or branched lateral lobes or
processes. The antennae are mostly rudi-
mentary. Flattened elytriform dorsal ap-
pendages are sometimes present. The ros-
trum is conical, tubular, and furnished with
two setaceous or styliform mandibles. The
alimentaiy canal is straight, without a
gastric expansion, and its orifices at the two
ends of the body. In some, branchial plates
form the respiratory organs ; but in most
the same office is performed by the skin.

The sexes are distinct, although they are
not known in all the species. The males
are smaller than the females. The ova are
often attached to the lower part of the body
of the females, either contained in external
ovaries, or simply glued together by the
secretion from a special gland, and forming
long, cylindrical, straight or convolute ap-
pendages. The young animals have but few
legs, swim freely, and frequently resemble
the young of Cyclojis.

\

BiBL. Baivd, Br. Entomosfr. ; M. -Ed-
wards, Ilist, Nat. Crust, m.; Siebold, Veryl.

SIROC'ROCIS, Kiitz. — Probably the
mycelium of a fungus.

BiBL. Kiitzing, Sp. Alq. p. 153.

SIROGO'NIUM, Kiitzing.— aS. not<Mle =
Mesocarjms notabilis, Hass. ; S. sticticuin =
Spiroffyra {Zi/ynema, Hassall) stictica; S.
hreriarticulafiim = Spiroqyra curvata.

SlROSrPHON, Kiitz.— A genus of Os-
cillatoriacese (Confervoid Algae), which
should perhaps have been placed under the
older name of HassalUa, This genus is
principally distinguished by the solitary
branches passing off from the sides of the
rather rigid filaments, the branches arising
from longitudinal division and lateral growth
of interstitial cells. The plants are black,
and found on wet moors, rocks, &c. Two
species seem to be established — "S". oceUata
(PI. 8. fig. 12), and S. compacta ; Leigh-
ton places the latter among the Lichens;
others appear doubtful.

BiBL. Hassall, Ah/. 231 ; Kiitzing, Sp.
Alg. 315, and Tab. Phi/c. ; Leighton, Lich.
Fl. 9 ; Rabenhorst, Alg. ii. 285.

SKELETON LARVA.— The larva of
Corethra plumicornis, a dipterous insect, of
the family Tipulidee.

It is very transparent, and shows well the
internal structure.

BiBL. Westwood, Insects, ii. 515 ; Prit-
chard, Micr. Illustr. 50.

SKELETONS 'MA, Grev.— A genus of
Diatomaceae.

S. Barhddense, in the Barbadoes deposit.
(Grev. Micr. Tr. 1865, 43.)

SKIN OB INTEGUMENT OP AnIMALS. —

Three parts are distinguishable in the skin :
an outer or cellular, forming the epidermis ;
an inner fibrous, or cutis vera ; and an inter-
nal or subjacent, Imown as the subcutaneous
cellular tissue. The two former constitute
the skin proper.

The cutis vera or corium (fig. 641 c) con-
sists of connective and elastic tissue, with
fat-cells, blood-vessels, nerves, absorbents,
and unstriated tnuscular fibres. The fibres
of the connective tissue are variously inter-
laced and united into interwoven bundles,
forming a tolerably dense and firm tissue,
with small areolae, and sometimes presenting
laminae. The elastic tissue is less abundant
than the connective, and consists of net-
works of finer or cofirser fibres.

The outer surface of the cutis gives off
a number of conical processes or papillae

SKIN.

[ 696 ]

SKIN.

(fig. 641 e), which are frequently bifid,
lobed, or arise several from a common base.
In many parts of the skin they are arranged
in more or less regular rows.

In certain papillfe, the connective tissue
is often horaogeueous, especially in the me-
dian portion, where it forms an oval trans-
parent body (fig. 642 rt), surrounded by a
layer of imperfectly developed elastic tissue,
consisting of spindle-shaped cells and fibres
taking a horizontal or circular direction,
and giving the oval body a transversely
striated or laminated appearance. These
are called tactile corpuscles, and are most
abundant at the ends of the fingers and in
the lips. See also Pacinian Corpuscles.
The cutaneous papillae are traversed by the
terminal loops of the capillaries (fig. 642 d)
and nerves (fig. 642 c).

The cutis is continuous beneath with the
subcutaneous cellular or properly areolar
tissue (fig. 641 d), which is of a much more
lax texture than the cutis, presenting large

areolae filled in most but not all places with
fatty tissue (fig. 641/).

The cutis is everywhere covered externally
with a thin membrane, and this by the epi-
dermis, which is a semitransparent coat,
containing neither vessels nor nerves, mould-
ed as it were upon the surface (fig. 648)
and filling up the intervals between the pa-
pillae (fig. 644). The vai'iously arranged lines
seen upon its outer surface are depressions
corresponding to those existing upon the
cutis between its rows or groups of papillfe.

The epidermis consists entirely of nu-
cleated cells ; and two distinct layers are
recognized in it (fig. 643), an inner forming
the rete mucosum (fig. 643 c), and an outer
or cuticle (fig. 643 6?). The rete mucosum
is softer than the cuticle, and is fre-
quently of a brownish colour, from its
cells, especially the deepest, containing gra-
nules of jjigment. These cells are not all of
the same form, those immediately applied
to the cutis beinof somewhat elongrated and

Fig. 641.

Fig. 642.

l-M

e

L.-

<^^'

../

,/

%

Fifj. 641. Perpencliculap spcti'on of the skin of the under surface of the end of the thtimh, throueh three furrows,
a, cuticle; 6, rete mucosum; e, cutis Tera ; </, upper part of subcutaneous tissue; e, papilJse of the cutis; y, fatty
tissue ; g, sudoriparous glands; A, sudoriparous ducts; t, orifice of the latter. Magnified 20 diameters.

Fig. 642. Paitillae from the skin of the under part of the end of the flufjer.
minai loop ; d, d, loops of capillary blood-vessels. Magniiled 2.50 diameters.

o, axial body ; S, nerve ; c, its ter-

SKIN.

[ 697 ]

SKIN.

arranged perpeiulieularly upon its surface
(ti"-. 043 b). The nwxt are somowhat cubi-
caF; and their surface often exhibits flat
processes or teeth, forming the so-called
" prickle-cells." The cells of the next rows
are polygonal, and contain one or more
nuclei ; tliey have a distinct cell-wall, and
some have hair-like processes.

The cells of the cuticle are colourless,
flattened, often wrinkled or folded, and
correspond to the pavement epithelium of
the mucous membranes. B tween the epi-
dermis and the cutis is situated a basement
membrane, which is easily distiuguishable.

In preparing the skin, it maybe hardened
by a mixture of chromic acid and alcohol,
and stained with picro-carmine. By keep-
ing a portion of skiii in a digestive liquid, as
pepsiue and dilute muriatic acid, the con-
nective tissue becomes transparent, and ex-
hibits clearly the muscular and elastic fibres.
In the examination of the skin, sections
must be made with Valentin's knife, and
these treated with acetic acid, solution of
potash, dilute nitric acid, &c. The blood-
vessels are well seen, as regards general

Fig. 043.

Pei-pendicular section of the skin of the Negro, a,
papillae of the cutis; 6, deepest and most intensely
coloured layer of elongated perpendicular cells of the
rete mucosum ; c, upper layer of the rete ; d, cuticle.

Magnified 350 diameters.

Fig. 044.

Under surface of the epidermis of the palm of the hand, cr, ridges corresponding to the furrows between the
ridges of the cutis; 6, ridges corresponding to the furrows between the rows of papillae; c, sudoriparous ducts;
d, their broad insertions in the epidermis; e, depressions corresponding to the papillae.

Magnified about 20 diameters.

SLATE.

[ 698 ]

SNOW.

arrangement, in injected preparations, some
of which, OS thuse of the pulp of the finger,
form very beautiful objects. The epidermis
is easily separated by maceration.

Fig. 645.

Per-Hon of the skin of tlie heel parallel to the siirfnce,
through one entire ridge of the skin and part of two
others ; showing tha arrangement of the papillse in rows
corresponding to the ridges of the cutis, a, cuticle
between the ridges; h, rete mueosum ; c, papillae; d,
portion of the rete mueosum between papillae arising
from a common base ; e, sudoriparous ducts.

Magnified 60 diameters.

The integument of animals is noticed
under the respective heads of the classes.

It must be remarked that the terms epi-
dermis and cuticle are generally used syno-
nymously.

BiBL. KiJlliker, Mik. An. i., and Geivebe-
lehre ; Todd and Bowman, Phys. An.;
Meissner, Beifr. z. An. ti. Phys. cl. Haut,
1863 ; Biesiadecki, Strieker's Hist.

SLATE. See Rocks.

SMARIS, or Smaridia, Latr. — A genus
of Acarina, family Trombidina.

Char. Palpi slender, inserted upon a re-
tractile rostrum ; mandibles sword-shaped ;
body entire, narrow anteriorly ; coxse stout,
distant, the anterior articulated to a fixed
eminence upon the body ; legs palpatorial,
u.sed also as palpi, the anterior longest.

S. jMpil/osa (PI. 6. fig. 36; a, mandible).
Body vermilion-coloured, broader in front,
depressed, covered with short cylindrical
papillfe rounded at the end. Fusiform
scales replace the papilhx; upon the legs,
palpi, and rostrum.

Found upon the trunks of trees, and in moss.

Several other species are found in moss,
upon fallen leaves, and on the debris left
after inundations.

In S. expalpis, Koch, there are no palpi.
BiBL. Duges, Ann. Sc. N. 2. i. 16 & 34;
Clervais, Walckenaer' s Apt. iii. 173; Murray,
Ec. Ent. 149.

SMIT'TIA, Hincks. — A genus of Esclia-
ridae (Cheilostomatous Polyzoa),=iey«"a^m
sp., with the secondary orifice elevated, pro-
duced, and channelled in front. 7 species.
(Hincks, Polyzoa, 340.)
SMUT. See Uredo.
SNAILS, WATER-.— Most microscopic
observers, ever anxious to determine the
unknown cau.se of the curious circulation
or rotation (Rotation) taking place in cer-
tain water-plants, as Vallisneria., Anacharis,
&c., keep these growing in large glass ves-
sels, as confectioners' jars, or Vivaria.
These plants, and the sides of the vessels,
are however very apt to become overgrown
and obscured by Coufervoid Algae (as CEclo-
gonium), Palmellaceae, &c., which ma^^ be
prevented by keeping water-snails in the
water, as species of Limttcetis, Physa, By-
thinia, Phmorhis, &c. The latter are best
for this purpose (the shell is flat-spiral).
If Desmidiaceas, Diatom aceae. Infusoria, &c.
are to be preserved, the snails must be care-
fully excluded, because many of these are
consumed by them, and will not live, as the
bottom of the vessels soon becomes covered,
when snails are kept, with a load of excre-
ment. The chanvcters of the snails are too
long to be given here. The gelatinous masses
of ova are found adhering to water-plants.
See the Bibl. of Mollusca.
SNOW. — The various forms presented by
ice or crystallized water in the form of snow
constitute beautiful although fugitive mi-
croscopic objects.

The crystals belong to the rhombohedric
or hexagonal system. Several hundreds of
forms have been observed, and many of
them figured. Among them may be men-
tioned hexagonal or dodecahedral plates ;
hexagonal prisms, single, arranged in a
stellate form, or terminated by rectangularly
placed plates or secondary groups of needles;
hexagonal pyramids. Sec. The angles of
these forms frequently constitute secondary
centres, around which other similar or dis-
siuiilar forms are aggregated. By some
authors these forms are regarded as skeleton
crystals.

See also Red Snow.

Bibl. Scoresby, ^nf/c Begions; Kamtz,

SODA.

[ G9f) ]

SPECTROSCOPE.

Mefeorolocfie; Glaisher, Mic. J». 1Sj5, iii. ;
Nauiuanu, Alinerahu/ie.

SODA. — KoUiker recommends a solution
of caustic soda, iu preference to potasli, for
the resolution of some of the tissues into
their conipt>ueut elements. We have been
unable to detect any marked dill'ereuce be-
tween the action of these two solutions;
and the former has the disadvantage of
lifting the stopper from the bottle by the
crystallization of the carbonate formed, so
that it is with diHicalty preserved.

PI. 10. fig. 15 represents the crystals of
oxalate of soda ; and fig. 19 those of the
nitrate (Urea).

SODIUM, Chloride of, or common
salt. — The crystals of this- salt belong to
the regiUar system. The most common
form is the cube terminated b}' quadrangu-
lar pyramids or quadrangular pyramidal
depressions, rectangular tables, &c. Schmidt
endeavours to show that the primaiy form
of the crystals is the octahedron, and that
the cubes are twin octahedra. The crystals
do not polarize light. (Schmidt, Entwurf
ein. allg. Untersuch. 90 ; and the Bibl. of

CHE>nSTRY.)

SCE.MMERIXG, Mirror of.— Intro-
duction, p. xxii.

SOLENOPH'RYA, CI. & Each.— A
genus of Acinetina.

Char. Sessile and with a membranous
lorica, tentacles simple, in distinct tufts. On
roots of Lemna. (Clap, et Each. Inf. 389.)

SO'EIUM, Heib.— A genus of Biddul-
phieie (I)iatomacea3). (Rabenh. Ahj. i. ol9.)

SOLORI'NA, Ach.— A genus of Phyl-
lodei (Eichenaceous Eichens). 4 species, in
mountainous districts. (Eeighton, Lich.
Fl. 106.)

SORAS'TRUM, Kiitz.— A genus of Des-
midiacese.

Char. Frond globular, composed of com-
pressed radiating cuneate cells, bifid at the
apex.

S. spinosiim (PI. 3. fig. 22), in stagnant
turf-pools.

Bibl. Kiitzing, Sp. Aly. 19.5; Rabenht.
Aly. iii. 81 ; Carter, Ann. N. H. 1869.

SORITES, Ehr. See Amphisorus and
Orbitolites.

SOROSPH^'RA, Br. — A free. Are-
naceous Foraminifer, with niunerous sub-
globidar thin-walled chambers (1-5" diam.),
loosely attached, and irregularly crowded.
H. confusa, in the Atlantic and Pacific,
900-2900 fathoms. (Brady, Qn. Mic. Jn.
n. s. xix. 9.)

SOROS TOR A, Ilass.— A genus of Pal-
mellacete (Confervoid Algae) not clearly
distinguished from Glococapsa and Proto-
coccus. (Ilassall, A/r/cfl, 309.)

SOROTHE'EIA, Kiirb.— A genus of Mi-
crolicJiens, parasitic on the thallus of /'///c-
iis art/ena. Spores 8, 2-locular, brown.
(Eindsay, Qn. M. J. 1869, 343.)

SO'RUS. — The name applied to the ag-
gregation of sporanges of llie Ferns; some-
times applied also to the groups of spores in
the Florideous Alg;e.

SPATHIDTUi^l, Du]. =Leucophn/s pt.

SPATHUEA'RIA, P.— A genus of Dis-
comycetes (Ascomycetous Fungi), with a
fertile head running down the stem on either
side. S. Jiavida is one of our prettiest
Fungi when in perfection.

Bibl. Grev. t. 165; Berk. Outl. t. 21.
fig. 7; Cooke, Handb. 661.

SPECTROSCOPE, or Microspectro-
.SCOPE. — The spectrum-analysis uf coloured
microscopic objects may be effected by
means of one or more prisms in connexion
with the simple or compound microscope.
The prism, or combination of prisms, may
be placed, either beneath the achromatic
condenser, in the body of the microscope, or
in the eyepiece ; and this last arrangement
is usually adopted. Sorby and Browning
have perfected the microscopic eyepiece.

Above the eye-glass of the eyepiece,
which is made achromatic and capable of
focal adjustment for rays of different refran-
gibility, is placed a tube containing five
prisms, two of flint glass interposed between
three of cro-wn glass in such manner that
the emergent rays which have been separa-
ted by the dispersive action of the flint-glass
prisms are parallel to the rays which enter
the combination. Below the eye-glass, in
the place of the ordinary stop, is a diaphragm
with a narrow slit, which limits the admis-
sion of light. Objects placed on the stage
of the microscope, provided they trar.smit a
sufficient quantity of light, may then be
examined, and their spectra observed. If it
is desired to corppare their spectra with any
other, provision is made for the formation of
a second spectrum, by the insertion of a
right-angled prism which covers one half of
the above-mentioned slit and reflects up-
wards the light transmitted through an
aperture in the side of the eyepiece. For
the production of the ordinary spectrum,
light is reflected into this aperture from a
smaU mirror carried at the side ; while for
the production of the spectrum of any sub-

SPERMATIA.

[ 700 J

SPERMATOZOA.

stance through which the light reflected
fr.tin the mirror can be transmitted, it is
only necessary to place the slide carrying
the section or crystalline tihn or the tube
containing the solution in the frame adapted
to receive it. In either case this second
spectrum is seen by the eye of the observer
alongside of that produced by the object
viewed through the body of the microscope,
so that the two can be exactly compared.
Some care is requisite in the arrangement
and number of the prisms according to the
amount of dispersive power required.

Crookes has devised a modification of this
apparatus, in which the prisms and slit can
be withdrawn and replaced without remo-
ving the eyepiece.

The spectroscope is of the utmost value
in microscopic, as in other researches ; but
its study is very difficult, and we have no
space to enter into its minute details.

BiBL. Sorbv, Qi(. Jn. 8c. ii. 198, Proc.
Boy. Soc. XV. 433, Mn. Mic. Jn. xiii. 198
(hluod-stains), aad Beales Hoiv, &c. 269 ;
Lockyer, Phil. Trans. 1874, 481, and Spec-
/roscoj)e ; Browning, Sj)ectroscope ; Schellen,
Spectroscope ; Proctor, Spectroscope ; Hug-
gins, Tr. Mic. Soc. 1865 ; Crookes, M. M.
Jn. 1869, 371 ; Suffolk, Spectr. Analys. ;
Vierordt, »S}^. Anal., quant., 1876 : Ward,
Jn. M. Soc. 1878, i. -326 {new spectroscojie) ;
Palmer, Mn. M. J. xvi. 277 {me<tsurement) ;
McMunn, Spectr. in. Med. 1881.

SPERMATIA.— The minute corpuscles
supposed to represent spermatozoids in the
Lichens (PI. 37. tigs. .3, 15, 16) and Fungi
(PI. 26. figs. 2, 3, 4).

SPERMATOZO'A of Animals. — The
form of the spermatozoa varies in dif-
ferent animals (PI. 50) ; but they usually
consist of a rounded or oval body or head,
to one end of which is appended a move-
able filament. This is their form in man
(tig. 25), and the Mammalia generally (tigs.
26-28) ; the former exhibit an undulating
membrane (Gibbes). In Birds, the body is
sometimes cylindrical, sometimes spiral or
presenting a zigzag outline (figs. 29-31).

In Reptiles, the body is usually cylindri-
cal and straight ^fig. 33), sometimes spiral;
they are very large in Amphiuma ; but in
some of theni, the straight or slightly undu-
lating terminal filament is surrounded by a
spiralfibreor Undulating Membrane (fig. 17).
In some instances, the so-called undulating
membrane consists of adherent portions of
the formative protoi>lasm.

In Fishes, the spermatozoa are usually

very small, and the body rounded, al-
though in some the body is spiral (fig.
34).

In the Invertebrata, a distinct body and
terminal filament are present in some ;
while in others each spermatozoon forms a
simple filament tapering at the ends (fig. 32).
la some instances, the body seems to exist
as a short cylinder or rod ; in others, the
spermatozoa are represented by simple cells,
or cells with radiating processes.

The development of the spermatozoa is not
agreed upon. In the higher animals, the
protoplasm of the peripheral cells of the
seminal canals gxows inwards into finger-
like processes, called spermatoblasts. In
each of these, a nucleus is formed, constitu-
ting the head of the spermatozoon, the pro-
toplasm at the end of the process growino-
into the filament, so that each spermato-
blast produces 8 or 10 spermatozoa. Ac-
cording to Kolliker, thej' are developed
witliin the epithelial cells of the tubuli,
nuclei or globules arising within these, in
each of which a spermatozoon is found
coiled up (PI. 50. figs. 35, 36). In some
animals, the spermatozoa are formed in
bundles, the bodies and filaments Iving
parallel with and opposite each other
(fig. 37). _ _ .

Most spermatozoa exhibit active move-
ments, produced by the action of the tila-
meut, whence they were formerly con-
sidered independent animals ; but tliese
movements are comparable with those of
the ciliated zoospores of the Algse, or the
cihated epithelium of animals; they are
increased by the addition of caustic potash.

In some animals, tubular sheaths are
secreted around the masses of spermatozoa
while contained in the seminal apparatus,
and called spermatophores. These, when
discharged from the organ, are fixed by tlie
male to the posterior end of the body of the
female by means of a glutinous secretion.

The spermatozoa are the essential fertili-
zing elements of the liquid in which they are
contained.

Spermatozoa may be best examined and
preserved by washing them with distilled
water, and drying them upon a slide.

BiBL. Kolliker, Mik. An. ii. ; id. Beitr.z.
Kcnntn. d. Geschlechts. d. wirb. Thiere ;
Czermak, Sieb. u. Kiill. Zeit. ii. ; Wagner,
Todd's Ct/cl. iv., art. Semen ; id. Physioloyy,
hy WiUis ; Leuckart, Wdyners Ilandwort.
d . P/iys. i\;. 819 ; Beneden, An. Conip. ;
Owsiannikoftj Mn. M. Jn. i. 312; Lankester,

SPEKMATOZUIDS.

C '01 ]

SPH.iiRlA.

Qu. Mic. Jn. 1871; St. ({mi^^^ Strieker's
Jlisf. ii. 141, and the liibL; Klein, Hid.;
Einer, Pkt/s. Med. Ges. Wiiiizhurc/, vi. 93 ;
Jolniston, M. Mic. Jn. xvi. 61 {Amphinma).

.SPERMATOZO'IDS, or ANTHERO-
ZO'IDS. — The terms applied to the struc-
tures produced in tlie antheridia of the
Cryptogamia, regarded as analogous to the
spermatozoa of animals, and as the agents of
fertilization of the germ-cell. In the Mar-
sileacefe, Lycopodiacese, Equisetacea?, Ferns
(PI. 40. figr34), Mosses (fig. 33), Hepatica?
(fig. 32), and Characea? (tig. 31), they are
ciliated spirally-coiled filaments, exhibiting
Tery active spontaneous motion. In the
Fucoid Algae, they are globular cells bearing
two unequal cilia moving actively. In the
Floridefe they are minute globular cells (PI.
4. tig. 12 rt),and neither cilia nor movement
have been demonstrated. In the Lichens
and Fungi the spermatia (PI. 26. fig. 4; PI.
27. fig. 23; PI. 37. fig. 15) appear to represent
the spemiatozoids of the other classes, and
they seem to be devoid of spontaneous move-
ment. The details respecting these bodies
are given under their respective classes.

BiBL. Thuret, Ann. Sc. Nat. 3. xiv. 214,
and xvi. o ; Schacht, Sperm, ivi Pflanz.
1864, &- Qu. Mic. Jn. IBGo.

SPERMOGO'IsIA.— The supposed an-
theridial structures of Lichens (PL 37.
figs. 2, 13, 15) and Fungi (PI. 26. figs. 1
and 4).

SPERMOSI'RA, Kiitzing.— A genus of
Nostochacese, growing in salt marshes,
containing two British species ; known
from the other genera by the disk-shaped
or lenticular cells ; but the filaments are
liable to be mistaken for a Nostoc in the
young state.

Spermosirn litorea, Kiitz. (PI. 3. fig. 20).
Filaments 1-3600" thick, straightish, a;ru-
giuous ; ordii ary cells confluent, very short ;
sporangial cells at first green, depressed-
spheroidal, 1-3000" in diameter, granular,
fuscous when mature ; vesicular cells trans-
versely elliptical, not wider than the ordinary
cells. lu muddy bracldsh ditches.

aS'. Harvey ana, Thwaites. P'ilaments
much curved ; cells nearly as long as broad ;
sporangial cells exactly spherical, almost
twice the diameter of the ordinary cells ;
vesicular cells subquadiate, rather longer
than wide, about as wide as the ordinary
cells. In muddy brackish ditches.
■ BiBL. Harvey, Brit. Alc/a-, 233, and Phijc.
Brit. ; Kiitzing, Tab. Phyc. i. ; Rabenhorst,
Alg. ii. It50.

SPIIACELA'RIA, Lyngb.— A genus of
Ectocarpacete (Fucoid Algte), containing a
number of species, two of wliich, S. .scoparia
and S. cirrhosa, are common. They have
joiuted,rigid, distichously branched,feathery
filamentous f'londs, of an olive colour, a few
inches high, and are especially characterized
by the sphacelcs formed at. the ends of the
branches. They multiply by zoospores pro-
duced in unilocular or plurilocular sporangia.
The propagula are produced on the lateral
branches, and are connected by a cell which
may produce several of them. Each con-
sists of a pedicel of three rays and of a
multicellular pair. The rays and pedicel
produce when they come into contact with
those of another Alga, short shields like a
prothallus, of which the peripheral cells
may produce new plants.

Bjbl. Hijrvey, Mar. Alg. 55; Janczewski,
Mem. Soc. Kat. de Cherbourg, xvi. 337.

SPH^E'RIA, HaU.— A genus of Pyreno-
mycetes (Ascomycetous Fungi), now some-
what reduced from its ancient limits, but
still containing a vast number of species,
which it is impossible to treat satisfactorily
within our limits. The forms vary chiefly
in regard to the perithecia, which are some-
times only covered by a veil, and hence
appear superficial on the matrix, while in
other cases they are imbedded in the matrix

Fig. 646.

Sphceria quaternata.

Thi-ee groups gi-owing on a piece of beech wood.

Magnified 20 diameters.

(PI. 26. fig. 25), only evident externally by
the black papilla, which is permanent,
becoming indurated, and opening by a pore
to discharge the spores in a fine powder.
Many of the immersed kinds are only evi-
dent externally as minute black points or
dots upon the snrface of the leaf, stem, ike.
which they infest ; others are exposed freely
when mature, breaking out from beneath the
epidermis. Sometimes they are solitary,
sometimes associated in small or ]ar<^e
numbers, distinct oi' confluent. <S'. quaternafa
(fig. 646) is an example of the occurience
of fi-ee perithecia grouped together, mostly
in fours ; being decumbent, their ostioles
are collected together, and they perforate
the bark by a little black rugged tubercle.

SPH.ERIA.

[ 702 ]

SPH.ERIACEI.

This is common on beech trees. <S'. con-
ven/em (figs. 647, 648) is an analogous form.
S. elongata (figs. 655-657 ) affords an example
of those species which are at first immei'sed
and adnate, and finally biu'st forth and
become nearly free.

Fig. 647.

Sphreria convergens.
Magnified 20 diameters.

Fig. 649.

Spliaeria verrucosa.
Magnified 20 diameters.

For species now separated from this genus
see Claviceps, Hypoxylon, Xylaria,
Hypoceea, and Necteia.

Certain points of great interest have lately
been ascertained respecting this genus and
its allies, which are mentioned under the
heads of the family and other genera, namely
the coincidence and evident connexion be-
tween true species of Sphceria and various
Coniomycetous Fungi ; for just as Melasmia
is a precursory foim of Dothiden, Tubercu-
lar ia of Nectria, &c., Cytispora, Septorta,
and other forms precede S^j/Ksria, and many
distinct stylusporous forms are associated,
usually described as belonging to distinct
genera, such as fiHi/boftpora, Sjwrocadus,
Sphcerojjsis, &c. Thus these plants seem to
produce three kinds of reproductive organs,
as is now known to be the case with the
Uredinei, viz. : — (1) a form analogous to the
spermogonia of the Lichens (in Sp/ieeria
represented by Cytispora, Szc.) ; (2) an
ascophorous fruit, the perithecium of the
true Spharia ; and (3) a stylosporous fruit,
representing the genera 8tilhof2>ora, Sporo-
cadiis, &c.

S. Lahurui has been found by Tulasne to
exhibit all these stages, namely perithecia
containing asci surrounding a cytispore,
•with other conceptacles on the same stroma
resembling the perithecia, but lined with
fitylospores instead of asci. Berkeley and

Broome also describe the existence of the
perithecia of Sphc^ria inquinmis and the
conceptacles of Stilbospora jnacrosperma on
the same stroma (PI. 26. figs. 25-28).

It is stated by Tuhisne that the spermatia
of the cytisporous forms may be conteuipo-
raneous with the stylospores orbasidiospores,
but they always precede the ascospores in
their development ; hence there is ground
for supposing that they represent the sper-
matozoids of the higher Cryptogamia.
With regard to the relations of the stylo-
spores, it is possible that they are merely
modifications of the ascospores ; but it
would appear probable that they must be
regarded as real gonidial structures, for
which it may be desirable to retain Fries's
name of conidia, just as that of tetraspores
is retained among the Florideous Algte.
Attention should be directed here to the
complete correspondence between the series
of forms of these genera and those of the
Uredinei, where, as in Puccinia, we
have the spernwyonium (cytispore), the
uredo (stylosporous fruit), and the perfect
fruit, (perithecium). See also Comomy"-

CETES.

Currey has published some extensive
observations on the spores of the Splicerim.

BiBL. Berk. Br. Fl. ii. pt. 2. 232 ; Ann.
N. H. i. 205, vi. 360, 2. v. 374, vii. 186 ;
Hook. Jn. Bot. iii. 319 ; Fries, Sum. Vcc/et,
388, Syst. Mycol. ii. 319; Tulasne, Ann.
So. iV. 3. XV. 375 (Ann. N. H. 2. viii. 117),
4. V. 108, viii. 35 5 Currey, Mic. Jn. 1855,
iii. 263, Linn. Tr. xxii. 257.

SPH^RIACEL— A family of Ascomy-
cetous Fungi, containing a vast number of
parasitic plants, mostly of minute dimen-
sions, growing upon leaves, stems, bark,
wood, &c., and sometimes on the bodies of
insects. The essential distinctive character
lies in the globular, ovate, or flask-shaped
conceptacle or perithecium., containing asci,
which ultimately opens by a pore at its
summit to discharge the spores. These
perithecia occur either solitary or in groups
on an indistinct matrix, growing out from
the epidermis of leaves, &c. {Sphariu) ; or
they are immersed in a tuberculnr stroma
{Nectria), while in the larger forms the
stroma becomes developed into an erect
clavate or bushy structure, of fleshy or
horny consistency, the perithecia being
imbedded in the superficial layer of this,
and opening by pores on tlie surface. Much
remains to be done in reference to the
history of this family, not merely on accoimt

SPH.ERIAOEI.

[ 703 ]

SPILERIACEI.

of the polyme>rphous characters of the asco-
phorous forms, but from tlie circumstance
tliat it has recently been shown, as was sus-
pected before, that there is a rehitiouship
existing between them and the supposed
genera of Coniomycetoiis Fungi of similar
habit. The.'se last are in fact mostly forms
of Sphferiaceous Fungi, as is indicated
under the heads Coxiomycetes, Ascomy-

CETES, DOTHIDEA, SpH^RIA, CytISPORA,

Septoria. Our treatment of this family
is very imperfect, the knowledge of them
being contined to few persons, and much of
it lying scattered in fi-agments. British
genera :

* Stfoma erect.

Claviceps. Stroma simple, clfivate ; peri-
thecia superficial, in a distinct layer at the
summit of the clavate stroma ; asci tubular ;
spores very long, multiseptate.

X;/!aria. Stroma simple or branched;
perithecia spread all over, often wanting at
the summit, olack ; asci eight-spored ; spores
uniseptate.

Fiff. 650.

Fig. 651.

So o«t

Ml'

,oaa

Fig. 652.

Xylaria guianensis.
Fig. 6.50. A stroma. Nat. size.
Fig. 6.51. Vertical section of the same. Nat. size.
Fig. 652. Section of a perithecium. Magnified 10 dia-
meters.

Thamnomyces. Stroma branched, shrubby,
or stalk-like ; perithecia formed from tlie
stroma, more or less naked ; asci tubular ;
spores simple, ovate.

** Stroma hetxoeen ei-ect and horizontal.
Poronia. Sti'oma cup-shaped, stipitate

or ses.sile, margined ; peritliecia in tlie disk,
superficial; ostioleseven sliglitly prominent.

*** Stroma horizontal.

Hifpocrea. Stroma distinct from the
raatri.x, tubercular; perithecia immersed;
asci filiform ; spores simple or uniseptate.

Hypoxylon. Stroma distinct from the
matrix, at first covered with a floccose
mealy veil ; perithecia black ; asci linear-
clavate; spores subseptate, expelled in a
cloud of black powder.

Fig. 653.

Fig. 654.

c':^^'

Xylaria grammica.
Pig. 658. Natural size
Fig. 654. Horizontal section. Magnified 5 diameters.

Biatrype. Stroma partly formed from
the matrix, not distinct ; perithecia deep-
seated, produced into a long neck, and
frequently a beak ; spores simple and pel-
lucid.

Dothidea. Perithecia uudistinguishable
from the stroma ; asci collected into a glo-
bose nucleus with a neck above, leadino- to
an ostiolate papilla.

**** Stroma loantiny ; the perthecia often
seated on a tuberculous, crusiaceous, bys-
soid, macular mycelium.

Nectria. Perithecia free, membranous,
flaccid, brightly coloured, with a pale
papilla, nucleus pale ; asci eight-spored ;
spores pellucid.

SPILEROBOLUS.

[ '04 ]

SPH^RONEMA.

Oomyces. Peritliecia erect, several cou-
taioed in a shiiiiug- sac, free towards the
upper part ; ostiole punctiform ; asci linear ;
spore iiliform, very long.

Splueria. Peritliecia black, papilla covered
by a veil or by the matrix, soujetimes beaked,
indurated, ostiolate, black ; asci usually
eig-ht-spored ; spores usually septate, dis-
charged as a powder.

Fig. 657.

Fig. 655.

Fio-. 656.

Siilioeria elongata.

Fig. 6-'i5. Eiumpent lines of perithecia. Nat. size.
Fig. 666. Portion of one in end view. Magnified 20

diameters.
Fig. 657. Asci and paraphysea from a perithecium.
Magnified 200 diameters.

SPIT^.ROB'OLUS, Tode.— A genus of
Kididavini (Gasteromycetous Fungi), con-
sisting of a peridium of several layers, the
inner one of which is suddenly reversed,
and discharges the globose sporangia.

BiBL. Tul. Fimq. Hyp. t. 21. f. 11 ; Berk.
Oiifl. tab. 21. f. 2 ; Cooke, Handh. 412.

SPHyEROCAR'PUS, Kiitz. = Staubo-

CAItPTJS.

SPH.EROCARTUS, Mich.— A genus
ofRiccieffi (Hepaticae). S. terrestris (fig.
658) is a minute Liverwort growing on the
ground, especially, it is said, in clover- fields.
The ironds are from 1-4 to 1-2" long, palish
green, very thin and membranous, the lower
surface adhering to the ground by radical
hairs. The middle part of the upper .surface
bears a quantity of fruits, which consist at
first of urchegonia and anthcridia, like tho.se
of other Liverworts, surrounded by a cu])-
like open pei-icha;te (?), which gradually
grows up over the fertilized archegonium
and closes at the lop, so as to form a pyri-
form sac, presenting an oriliceat thesunmiit.
The archegonium ripens into a globular

.sporange, containing spores without elaters,
Clowned by a curious Uttle styliform process.
The spores are discharged by irregular rup-
ture. The walls of the sporange are com-
posed of simple parenchymatous cells, with-
out spiral-fibrous layers. While the spo-
range is ripening, the perichsete enlarges
into a loose, obconical, green membranous
sac, through the thin walls of which the
globular sporange is visible (fig. 658).

Fig. 658.

6ph:erocarpu3 terrestris.

A frond with periebsetes containing sporanges;

one cut open.

Magnified 10 diameters.

RiBL. Hook. B): Flor. ii. pt. 1. 103 ; Bis-
cliofl". Nova Acta, xiii. 150 ; Lindeuberg, ib.
xviii. 406 ; Fitt, Huoker's J,i. Bot. 1847, vi.
287.

SPILEROCOC'CUS, Stackh.— A genus
of Rhodymeniaceai (Florideous Algfe), con-
taining one British species, S. coronopifolms
(PL 44. fig. 14), having a flat, linear, 'disti-
chously branched frond of crimson colour
and cartilaginous texture, of fan-like outhne;
parenchymatous, with an internal denser rib
and cortical layer; 6 to 12" long. The
upper branches have their margins set with
minute tooth-like processes, about 1-24"
long, in some of which the spherical concep-
tacles are imbedded.

BiBL. Harv. Mar. Ahj. 128; Greville,
Alq. Br. pi. 15.

SPH^ROIBI'NA, D'Orb.— A roundish,
sublobate, hyaline P'oraminifev, near Glohi-
(jerina, but of denser structure, and folded
somewhat like a Miliola. Recent and fossil.

S. anstriaca (PI. 24. fig. 4).

BiBL. Carpenter, Introd. For. 185.

SPIlyEROM'PIIALE.— A genus of Try-
petheliene (Angiocarpous Lichens), nearly
rehited to J^erriiraria.

SPHtERONE'MA, Fr. — a genus of
S]iha'ronemei (Stylosporous Fungi), charac-
terized chiefly by the spores wliich emeige
from the pore becoming glued together into

SPH^RONEMEI.

[ '05 ]

SPILEROPHORON.

a firm globule. The species, which grow
upon the surface of decaying plants, are pro-
bably onl)' forms belonging to Sphajriaceous
genera.

BiBL. Berk. Bi: Fl ii. pt. 2. 281 ; Ann.
N. H. vi. 363, lb. 2. v. 371 ; Fries, Sum. Veget.
400.

SPFL'EK0NE:ME'I.— A family of minute
Stylosporous Fungi, growing on bark, or
more or less dry stems or leaves, chai'ac-
terized by the couceptacle ordinarily burst-
ing by a pore or ostiole, or a Ud, to extrude,
in most cases, a gelatinous ball of filaments
mixed with spores. From recent observa-
tions it appears that the genera do not con-
sist of independent species, but are forms
which occur in combination with Ascomy-
cetous forms to complete the whole de-
velopment of an individual, — the Sphajro-
uemeous genera constituting the stylospo-
rous or couidial fruits of Sphaeriacei, &c.,
corresponding perhaps to the tetraspores
found in the Florideous Algee, which also
possess proper spores (see Sph^ria).
British genera :

ConiuthyrhiDi. Conceptacle free, mem-
branous, opening by an irregular pore at the
summit ; spores globular.

Leptostroma. Conceptacle innate, subum-
bouate in the centre, dimidiate, at length
falling off, leaving a very thin disk.

Phoma. Conceptacle ostiolate, very thin,
innate, immersed, roimded, with a simple
pore ; spores oblong, simple.

Lepfothyrium. Conceptacle operculate,
innate, shield-shaped, not radiate-fibrous :
spores spindle-shaped, simple.

Actinuthyrium. Conceptacle operculate,
innate, shield-shaped, radiate-fibrous ; spores
spindle-shaped, simple.

Microthecium. Conceptacle indehiscent,
membranous, immersed, endophytic ; spores
simple.

Cryptosporium. Conceptacle membranous,
opening u'regularly at the summit ; spores
spindle-shaped, simple.

Sphceronema. Conceptacle homy, innate-
superficial, more or less produced into a
neck, ostiole sunple ; spores oblong, simple.
Acrospermum. Conceptacle leathery ex-
ternally, fleshy within, elougate-clavate,
ostiole simple ; spores stick-shaped, simple.
Diplodia. Conceptacle horny, innate-su-
perficial or immersed, perforated by a pore
or irregularly opened or ostiolate, ostiole
more or less produced ; spores ovoid or
ellipsoid, double, then halved into com-
pressed-ternate semieUipsoid sporules.

Hendersonia. Conceptacle fleshy, super-
ficially innate or immersed, perforated by a
pore, opening irregularly or ostiolate, ostiole
more or less produced ; spores globose, cylin-
drical, or discoid.

Septoria. Conceptacle hom^y, innate-im-
mersed, rounded, ostiole simple ; spores
cylindrical, septate.

Vermicidaria. Conceptacle bristly, de-
pressed, bursting irregularly ; spores minute,
linear.

Neottiospora. Conceptacles immersed ;
spores appeudaged at one end with short
hyaline threads.

ProstJiemium. Conceptacle horny, immer-
sed, ostiole simple; spores transversely
septate, verticillate at the apex of their fila-
ments.

Asteroma, Conceptacle very small,
slightly prominent, close, subconfluent,
seated on more or less distinct radiating
fibrils.

Angiopoma. Conceptacles free, mem-
branous, somewhat horny, cup-shaped, de-
hiscing by a cu'cular mouth, provided with
a fugacious epiphragm ; spores affixed at
the base, stalked, septate.

Discosia. Conceptacles innate, somewhat
carbonaceous, at length coUapsed and plicate,
ostiole perforated ; spores fusiform, produced
at both ends into a thread-like point.

Piggotia. Conceptacles very irregulai',
thin, obsolete beneath, confluent into a ru-
gulose patch, bursting by an irregular crack ;
spores on short stalks, largish, obovate,
somewhat constricted towards the base.

Phlyctana. Conceptacle spurious, formed
by the blackened epidermis; spores fusi-
form, cuspidate, septate, emerging accom-
panied by a gelatinous mass.

Glceosporium. Couceptacle absent ; spores
covered only by the cuticle, which separates ;
spores stalked, longish, elliptical, simple,
exuding a gelatinous tendril.

Dilophosphora. Conceptacle immersed in
a spurious stroma, covered, perforated by a
pore ; spores cylindrical, continuous, crow-
ded at both ends with radiating filiform
appendages.

Splueropsis. Couceptacle spherical, im-
mersed, subinuate, astomous, at length (by
the separation of the epidermis) bursting by
circumscissUe dehiscence or irregularly.
Spores simple.

SPH^ROPH'ORON, Pers.— Agenus of
Epiconiodei (Lichenaceous Lichens). Thal-
lus erect, shi'ubby, externally crustaceo-car-
tilaginous, internally solid and cottony.

2z

SPH^ROPHRYA.

[ 706 ]

SPH.EROPLEA.

Apotliecia terminal, spherical, the peritlie-
cium, formed of the thaUus, closed, dehiscing
irregularly. Nucleus globular, internally
floccoso-cartilaginous, the discharged (black)
sporidia crowded in the circumference.

S. coralloicles (fig. 395, p. 463), and S.fra-
f/ile, common on sand-rocks, among mosses.

S. compactum is rare. The spermoyonia
occur at the ends of the more delicate
branchlets of the thaUus.

BiBL. Hook. Br. Fl. ii. pt. 1, 236 ; Leigh-
ton, Lich. Fl. 48 ; Tulasne, Ann. Sc. Nat. 3.
xviii. 209.

SPH^ROPH'RYA, Clap, et Lach.— A
genus of Acinetina.

Char. Tentacles simple, radiate ; no sheath
or peduncle ; body free.

S. pusilla, small, spherical ; freshwater.
(Clap, et Lach. Inf. 385.)

SPILEROP'LEA, Ag.— A genus of Cou-
fervacete of uncertain position, but proba-
bly allied to the Chsetophoracese. It is cha-
racterized chiefly by the formation of the
spores. The plants consist of simple fila-
ments, Avith long joints, at first containing
green colouring-matter excavated by large
vacuoles, producing a banded appearance
(PL 9. fig. 14 a), the contents in the fertile
cells finally resolving themselves into nume-
rous spinulose globular spores arranged in
longitudinal rows (6), which become red
when ripe.

The development of the spores of *S'. cmtiu-
lina has been observed by several authors ;
and Cohn has published an account of the
formation of spermatozoids in distinct cells,
exercising a fertilizing function. The fila-
ments, which always terminate in pointed
hair-like ends, present when actively vege-
tating the excavated or banded appearance
of the green contents above noticed ; the
vacuoles separating the bands of a proper,
colourless, mucilaginous coat. When about
to produce spores the regidarity of the bauds
vanishes, the vacuoles multiply in number in
the substance of the bands, and the contents
present the appearance of a gveenfroi/i with
starch-granules scattered through it. After
a time a number of green corpuscles, the
spores, appear in the median line of the cell ;
these assume a stellate shape, with radiating
threads of protoplasm connecting them to-
gether ;. they soon appear in pairs, sepai-ated
by transverse false septa, formed by the
flattened vesicles of the vacuoles. The spores
gradually become better defined, and the
false septa disappear ; then the young spores
present themselves as globular bodies, de-

void at this time of a cellulose coat. From
two to six minute orifices are preceptible at
this time in the partially softened wall of
the parent cell. While these phenomena are
occm-ring in some of the cells, a different
change takes place in others. The green
bands assume a reddisli-yellow colour, their
starcli disappears, and they are gradually
converted into myriads of short stick-shaped
bodies, which break apart and " swarm "• in
vast numbers, filling the whole cell, moving
actively in all dLrections. The gelatinous coat
of some of the vacuoles sometimes remains
intact ; and these then He free in the cavity
of the cell, and are often carried about by
the rapid motion of the corpuscles. Orifice's
are meanwhile formed in these cells also,
through which the stick-shaped bodies
(spermatozoids) escape into the water. Their
length is about 1-3000". The hinder end
now appears somewhat swollen, and they
bear two long cilia on the pointed beak— in
fact resemblmg the mivrogonidia of the other
Confervoids. Cohn states he has seen them
accumulate aroimd the orifices of the spore-
cells, enter the cavities of these, and swarm
about in the interior, in considerable num-
bers, at length adhering to the young spores.
These restiug-spores then acqiui-e a mem-
brane, and under this a second , which is
at_ first smooth, but afterwards presents a
spinulose or stellate appearance; the first
coat is then thrown oft, and a third, smooth
coat appears under the stellate coat, closely
investing the contents. These conditions
resemble those of the spores of Spirogyba
and other Confervoids ; Spirogyra, however,
retains the outer coat until germination.
The green contents of the spores ultimately
turn red. Their size and number in a cell
vary much.

Cohn has also observed the gemiinatiou
of these spores, which is interesting in se-
veral respects. Their ordinary size is from
1-1200 to 1-1500" ; and they present, as
above mentioned, two coats, the outer ele-
gantly marked ; most authors describe it as
stellate ; Kiitzing asserts that it is spirally
folded. The real fact is, that it is plaited
in the direction of meridians from pole to
pole, and thus appears stellate when seen at
either pole, marked with lines Avhen seen
sideways. The spores do not appear to ger-
minate until the spring following their pro-
duction. The red contents begin to assume
a green colom- from the' surface inwai-ds,
divided into two, then into four or eight
portions, which break out from the spore-

SPH.EROPSIS.

[ 707 ]

SPHrEROZYGA,

cell, and swim about as free biciliated zoo-
spores, of globidar or shortly cylindrical
form, from 1-2280 to 1-1680" long, either
bright red or particoloured red and green,
the point bearing the cilia, however, always
colourless. After a time they become
coated with a cellulose membrane, cease to
move, and grow into a spindle-shaped body,
the ends prolonged into hair-like points.
The growth appears to be always in the
middle, the hair-Uke points remaining ;
thus the spindle-shape is retained until the
length reaches 1-24' or more, and the first
septum appears in the middle of the filament,

S. annulina (PI. 9. fig. 14) appears to be
the only well-known form. It is a rare
Conferva, growing on flooded fields ; it
does not seem to have been recorded in
Britain.

For Sph. crispa and purictalis, see Ulo-

THEIX.

BiBL. Kiitz. Sp. Ah/. 362, & Tab. PJtyc. ;
Braun, T'erjiinc/unf/, Ray Soc. 1853, 165;
Cohu, Ber. Berlin. Ak. 1855 ; Ann. Sc.Nat.
4. v. 187 ; Ann. N. H. 2. viii. 81 ; CienkowsM,
Bot. Zeit. xiii. 777 ; Eabeuht. Ahj. iii. 318.

SPH^^ROPSIS, Lev.— A genus of Sphse-
ronemei (Stylosporous Fungi), growing
upon stems, &c. ; apparently only stylospo-
rous forms of Sphseriaceous genera.

BiBL. Fries, Sum. Veget. 419 ; Tulasne,
Ann. Sc. Xat. 4. v. 115.

SPH.^ROP'TERIS, Wall.— A genus of
Dicksonieee (Polypodiaceous Ferns). 8.
harbata ; India. (Hooker, Syn. 49.)

SPmEROSlRA, Ehr. See Vol vox.

SPH^ROTHE'CA.— A genus of Sphjs-
liacei (Ascomycetous Fmigi), closely allied
to Erysiphe. S. pannosa is common on the
leaves and fruits of a rose ; S. Castaynei, on
the leaves of hops &c. (Cooke, Handb, 645 ;
Tulasne, Carp. i. 208.)

SPH^EROT'ILUS.— A genus of Crypto-
coccese, consisting of cells an-anged in rows,
connected by mucus, forming a flocculent,
variouslj- divided floating layer. S. natayu
(PI. 3. fig. 21), brownish, in organic liquids :
said to purify the water.

BiBL. Rabenht. Alg, ii. 8 ; Eyferth, Jn.
Mic. Soc. 1881, 97.

SPH^ROZOS'MA, Corda.— A genus of
Desmidiacese.

Char. Filamentous; filaments flat, fra-
gile, their component coUs closely united
by means of minute (glandular) processes,
and deeply divided on each side into two
seg'ments.

S. vertebrattmi (PI. 14. fig. 9, front view ;

fig. 10, side view). Cells about as long as
broad ; connecting processes oblique, one on
each side. Length of cell 1-1430". Not
uncommon in ditches.

S. excavatum. Cells longer than broad ;
connecting processes sessile, two on each
side. Length of cell 1-2570".

After separation, the cells conjugate ; spo-
rangia elliptical. Other species.

BiBL. Ralfe, Br. Desmid, 65 ; Rabenht.
Aly. iii. 148.

SPH.EROZO'UM.— A genus of Radio-
larian Rhizopoda.

It consists of a spherical group of rounded
bodies consisting of sarcode with distinct
nuclei, surrounded by a zone of siliceous
spicules, the whole being imbedded in a com-
mon gelatinous matrix. The centre of the
mass is vacuolated; and the whole often
becomes a hoUow sphere. (Huxley, Comp,
Anaf. ; Carpenter, Microscope.')

SPILEROZ'YGA, Agardh {Anabcena,
Bory, Brebisson). — A genus of Nostocha-
cese, difleriug from the allied genera only in
the sporaugial ceUs being separated by vesi-
cular cells. As the sporaugial cells are de-
veloped from the ordinary cells, and this
gi-adually, the vesicular cell will appear at
certain epochs to have a sporangial cell on
one side and an ordinary cell on the other ;
but this arises merely from the fact that
the sporangial cells are developed singly
and successively, first one on one side of
the vesicidar cell and then one on the other,
and so on, to whatever number of adjacent
sporangial cells there may be developed on
either side of the vesicular cell ; and those
nearest the latter will therefore always be
the largest, until the whole have acquired
tlie full size. Ralfs describes seven British
species.

* Filaments moniliform; sporangia elonyated,
not turyid.

S. Carmichaelii. Filaments with tapering
exti-emities ; ordinary joints distinct, sub-
quadrate ; sporaugial cells oblong ; vesicular
cells spherical. — Ralfs, Ann. N. H. 2. v. pi.
8. fig. 7 ; Harvev, P/ujc. Br. pi. 113 A ; Mar.
Alyce, 2. ed. pi. 27. fig. D.

Belonia toridosa, Carmichael ; Sphcerozyga
compacta, Kxxiz. ; Anabcena marina, Brebis-
son ; Cylindrospernium Carmichaelii, Kiitz.
Sp. Aly. 294, Tab. Phye. i. pi. 99.

Var. tenuissima, with very slender fila-
ments. Forming a tender, very thin stra-
tiun of a dark or bluish-gi-een colom*, on the
damp soil of salt-marshes flooded at spring

2z 2

SPHAGNACE^.

[ 708 ]

SPHAGNACE^.

tides, more rarely iu brackish ditclies, or i
upon decaying marine Alga?,

The best distinctive marks of this species
are, the subacute extremities, combined
with the short filament and littoral habit.

S. Jacohi. Filaments elongated, their ends
usually' attenuated ; ordinary cells subsphe-
rical; vesicular cells spherical; sporangia!
cells oblong or cj-lindrical. — Ralfs, I. c. pi. 8.
fig. 8; Eny.Bot. 2826. fig. 2. Forming thick,
bluish-green, gelatinous masses, fii'om which
the filaments issue in long rays. Fresh-
water.

S. eladica (PI. 8. fig. 3). Dissepiments
conspicuous ; ordinary cells quadrate ; vesi-
cular cells eUiptic ; sporangial cells cjdiu-
drical, trmicate. — Ealfs, I. c. pi. 8. fig. 9.
Cylindrospenmim elonfjatum, Kiitz. Tub.
Phi/c. i. pi. 99. fig. 3. Forming a tender
stratum, of a deep bluish colour", in bogs.

** Filaments moniliform; sporam/ia turyicl,
much broader than the ordinary cells.

S. Broomeij Thwaites. Filaments elon-
gated ; ordinary cells suborbicular ; vesicu-
lar cells barrel-shaped or elliptic ; sporangial
cells elliptic, catenate. — Ralfs, /. c. pi. 7.
fig. 10. Forming a firmish bluish- or yel-
lowish-green stratimi in brackish ditches.

*S'. Berkeleyana, Thwaites. Ordinary
cells spherical or slightly compressed ; vesi-
cular cells spheroidal, compressed, as broad
as the large, turgid-elliptic, sporangial cells.
— Ralfs, I. c, pi. 8. fig. 11. In brackish
ditches.

<S'. Mooreana, Ralfs. Ordinary cells sub-
spherical; vesicular cells barrel-shaped,
much narrower than the large, broadly
elliptical sporangial cells. — Ralfs, /. c. pi. 8.
fig. 12. An Lish species.

*** Dissepiments obscure ; cells longer than
broad.

S. leptos2)erma (Kiitzing). Filaments
elongated, not constricted at the dissepi-
ments ; ordinary cells longer than broad,
confluent ; vesicular cells elliptic ; sporan-
gial cells linear. — Ralfs, /. c. pi. 8. fig. 13.
Cylindrosjjermuni leptospermum, Kiitzing,
Tab. Phyc. i. pi. 99. fig. 2. Forming large
shapeless gelatinous masses in still waters,
varying from deep green to yellowish green,
or, when the filaments are comparatively
few, nearly colourless. Distinguished espe-
cially by the " confluent ordinary cells with
obscure dissepiments."

SPHAGNA'CE^.— A family of Clado-
cai-pous Mosses, of pecidiar habit, growing

in bogs &c., distinguished especially by the
mode of branching, the structm-e of the
leaves, sporanges, and antheridia, and by
the absence of roots, except in the early
stages of growth.

The stem of the Sphayna is composed of
three layers of cells, — a cortical, a medullary,
and an intermediate prosenchymatous layer,
which finally becomes somewhat woody.
The primary axis is indefinite in its gro'wth ;
the lateral axes, steiile or fertile, are an-
nual. The secondary axes are fascicidate ;
and being pendent or recurved upon the
stem, they fulfil in some measm-e the func-
tion of roots. The leaves are remarkable for
their cellular sti'ucture, being composed of
two kinds of cells — namely, narrow and
elongated cells filled with chlorophyll, con-
joined into a kind of network, the meshes
of which are occupied by large hyaline cells.
The hyaline cells contain, in all but one
exotic species, a spiral or annular secondary
deposit (PI. 48. fig. 25) characteristic of
this family. These large cells also become
opened by regidar circular pores at a certain
stage of growth.

The inflorescence is monoecious or di-
oecious. The antheridia are produced singly
in the axils of perigonial leaves at the club-
shaped tips of short branches. They are
pedicellate and roundish, like those of the
Liverworts ; they produce biciliated sper-
matozoids. The archegonia are found about
four together, sessile, in a tuft of perichaj-
tial leaves occupying the axis of a fascicle
of branches, the receptacle subsequently
elongating into a peduncle, bearing a glo-
btdar capsule, entirely surrounded by the
calyptra. The cah-ptra is ruptured near the
middle, the lower part persistent and con-
tinuous with the fleshy vaginule, within
which the capsule. is seated on a bulb-like
pedicel : peristome none ; operculum flattish,
thrown oft' with elasticity. Spore-sac
wanting ; columella short, not reaching the
mouth of the capsule. Spores apparently of
two kinds, some enclosed four together in
parent cells, others smaller, sixteen in one
parent cell : the former fertile, the latter
sterile, occming either together or in di-
stinct capsules. The spores in germinating
produce a Marchantioid body, very dillerent
from the confervoid mass of ordinary mosses.

British Genus.
Sphaymim, Dill. Character that of the
order. Nine species occiu- in Britain, some
common on every bog, distinguished by

sphagnoc(t:tis.

[ 700 ]

SPINAL CORD.

their brilliant yellow-f^reon colour and the
wet, spongy character of the beds they form.
The leaves are very interesting microscopic
objects.

Rotatoria are sometimes found in the cells
of the leaves. Also upon or within the
same, the cm-ious parasitic Rhizopod —
Chlamijdopi/xis lahi/riufhidoides. This, in the
resting-stage, consists of a laminated thick-
walled cellulose red or green cell. As the
organism grows, it bursts the cell-wall, and
the protoplasm issues in the form of nu-
merous very slender radiating filaments,
along which glide minute fusiform bluish-
green amoeboid bodies. It seems to bear
analogy with the Myxomycetes.

BiBL. Wilson, Bryol. Br. 14; Schimper,
Ann. Sc. Nat. 4. i. 31.3 ; Braithwaite, Mosses ;
Archer, Qu. M. Jn. 1875, xv. 107 {Chla-
mydopi/.vis) ; Husnot, Sphay. Europ. 1882.

SPHAGXOCCE'TIS, Nees.— A genus of
Jungermannieae (Hepaticfe), containing one
species, (S". (Junff.) Sphagni, an elegant little
plant gTOwing over Sphagnum and other
mosses on bogs ; attaching itself by long
radicles, numerous on the under side of the
procumbent, nearly simple stem. The gem-
miferous branches only have amphigastria.

BiBL. Hook. i?r. Fl. ii. pt. 1. 113; Br.
Juni]. pi. 33, and Suppl. pi. 2 ; Ekart, Syn.
Junq. pi. G. figs. 43 & 48.

SPHEXE. See Rocks.

SPHENEL'LA, Kiitz.— A genus of Dia-
tomacese.

This genus appears to consist of the de-
tached frustules of Gomphonema. Klitzing
describes seven species. S. vulgaris (PI. 19.
fig. 19).

BiBL. Kiitz. Bacill. 83, Sp. Alg. 62 j
Rabenht. Alg. i. 282.

SPHENODE'RIA, Schlum.— A doubtful
genus of Arcellina (Rhizopoda).

It is allied to Euglyphe and Trinema.

BiBL. Pritchard, Infusoria, p. 557.

SPHEN0:M'0NAS, stein.— a genus of
Flagellate Infusoria. Free, surface hard ;
flagella two, one long, one short ; a tubidar j
pharynx. Two species ; freshwater. (Kent,
Inf. 438.)

"SPHENOSI'RA, Ehr., KUtz.— A genus
of freshwater Diatomacepe. Diatomace.^,
p. 244.

S. catena (PL 17. fig. 26).

BiBL. Klitzing, Sp. Alg. 68 ; Rabenht.
Fl. Eur. Alq. i. p. 293.

SPHIXCTOCYS'TIS, Hass.,=CYMATO-

PLEUEA, Sm.

SPHINCTRI'NA.— A genus of Calyciei

(Lichenaceous Lichens), with little stalk-
like excipula and scarcely distinguishable
thallus, growing on leaves or Fertumrim,
(Leighton, Lich. Fl. 38.)

SPICULA (plural of spierdum). — In some
of the lower Invertebrata, firmness is given
to the body by a kind of internal and
external skeleton consisting of a number of
curiously shaped microscopic bodies, many
of which are of a needle-like form, often
containing a cavity, and denominated spi-
cula. They are met with in endless variety
of form in sponges (see Spongida) (PI. 45,
the lettered objects), where they usually
consist of silex, some being of carbonate of
lime. They also occur as anchors &c. in the
Echinodermata (PI. 45. figs. 1 h, i, k, I, and
19 a, b, c), the Foraminifera (PI. 23. fig. 24),
and in some of the Zoophytes {Alcyonimn)
and Mollusca (Doris), in these instances
being calcareous.

There can scarcely be doubt that s})icula
are homologous with the elements of shell ;
but little or nothing is known of their
development. They form very interesting
microscopic objects, on account of their
remarkable forms.

To prepare them, the animal substance
in which they are contained should be
boiled with nitric acid if they are composed
of silex, and with dilute solution of potash
if they consist of lime-salts. They may be
preserved by mounting in Canada balsam.

They are commonly met with iu sea-
mud, and as fossils in some rocks.

SPIDERS. See Abachniba.

SPILOCiEA, Fr.— A genus of Torulacei
(Coniomycetous Fungi). S. Pomi occurs
upon apples, in contiguous effused patches,
from which the epidermis separates in frag-
ments, exposing the simple globular spores,
adherent to each other and to the matrix.

Probably only a state of Cladosporinm.

BiBL. Berk. Br. Fl. ii. pt. 2. 360 ; Fries,
Sum. Veqet. 482,

SPILONE'MA, Fries.— A genus of Col-
lemaceous Lichens.

Cliar. ThaUus filiform, branched, fruti-
culose, granula gonima large, in transverse
strata. Apothecia lecideine, lenticular.
Spermatia shortly cylindrical. 3 species,
on rocks. (Leighton, Lich. Flora, 10.)

SPINAL CORD.-The spinal cord of
man is that part of the central nervous
system which extends downwards from the
medidla oblongata, occupying much of the
vertebral canal, and terminating in a conical
extremity at the level of the first lumbar

SPINES.

[ 710 ] SPIRAL STRUCTURES.

vertebra. The cord is composed of white
substance, grey substance, and blood-vessels
(PI. 52. fig. 7).

The white substance («) is mostly ex-
ternal, and forms the antero-lateral and
posterior longitudinal columns, besides the
transverse anterior commissure at the end of
the anterior longitudinal fissui-e. It is com-
posed of nerve-fibres of large and medium
size, of connective tissue, and blood-vessels.
The grey substance (c) is internal, and in
transverse section of the cord presents a
shape which may be roughly compared
with that of the letter H. On either side
there is an anterior and posterior horn or
cornu; and the median line of the letter is
represented by a soft grey commissm'e per-
forated by a canal, which is central and
lined with epithelium, SuiToimded on all
sides by the white substance, the anterior
and posterior spinal nerves reach their re-
spective cornua by crossing at different angles
along two lines on either side of the ge-
neral direction of the nerves of the white
substance.

The grey substance contains a large num-
ber of very fine nerve-fibres, which are
united in a plexiform manner with nerve-
or ganglion-cells ; most of these fibres pass
outwards and become spinal nerves, belong-
ing then to the white substance or to di-
stinct nerves. There is moreover granular
matter with highly refractive globules, and
extremely small nucleated cells surrounding
the nerve-fibres and ganglion-cells. Much
connective tissue exists in the neighbourhood
of the central canal and in the posterior
cornu.

The examination of the spinal cord and
the brain is so difficult and not likely to be
the subject of general investigation, that
we must refer to the Bibl. for further de-
tails.

BiBL, Todd's Ci/cl. An. ^- Phys. ; Lockhart
Clarke, Phil. Tr. 1858, 1868 ; Strieker's
Hist. ii. ; Frey, Hist., and the Bihl.

SPINES OF Animals. — These are pro-
perly stout rigid and pointed processes of
the integument, formed externally by the
epidermis, and internally of a portion of the
cutis or corresponding structure ; but the
temi is frequently ajiplii'd to stout rigid and
puintf d processes of the epidermis only.

See Hairs, and the notices of the struc-
ture of the integument under the heads of
the various classes.

SPIRACLES or Stiumata of animals.
— ^The external orifices of the tracheaj of

Insects and Arachnida. The respiratoiy
tubes of these animals have no communica-
tion with the mouth, but terminate exter-
nally in orifices situated upon the surface of
the thorax or abdomen. These are mostly
rounded or elliptical (PI. 35. figs. 3, 7, 8,
and 9 a), sometimes in the form of small
clefts, and are often furnished with a kind
of moveable valve, or bounded by a thick-
ened rim ; sometimes a sieve-like sti'ucture
(PI. 34. fig. 34) prevents the admission of
foreign bodies, or they are surrounded by
hairs or scales effecting the same purpose.

They are often situated at the lateral
and upper portions of the abdomen, at the
posterior, lateral, and upper part of the
thorax, &c.

See Arachnida, Insects, and the
genera.

SPIRAL STRUCTURES of Plants.—
Among the most elegant of the microscopic
objects fm-nished by the Vegetable King-
dom are the various forms of the secondary
deposits upon the walls of cells, vessels, and
ducts, Sec, which present the appearance of
fibres coiled into perfect spirals, or of spiral
fibres either with the coils detached and
forming rings, or with the coils more or less
connected by cross pieces, producing a re-
ticulated structure.

Under the head of Secondary Deposits
it is stated that tliis spiral-fibrous deposit
may be taken as the character of a group of
structm-es to be contrasted with those struc-
tures described as Pitted ; and that the
essential distinction in the nature of these
two groups lies in the greater extent to
which the primary wall is covered in the
pitted structures. This is not quite absolute
in reference to all spiral-fibrous structures,
as in the true unrollable spiral vessels and
similar organs the coils of the spiral fibres
are often closely in contact, although not
adherent to each other. It has been stated
that the various fonns of the open spiral,
annular, and reticulated deposits are modi-
fications of the simple close spiral ; but this
must be understood only in a moi-pholo-
gical sense, since there is no actual change
of condition ensuing with age, as has been
assumed by some authors, the fibrous layers
being always •originally deposited on the
primary wall in the form and pattern which
they ultimately possess. There appears to
be no j-eal opening of the s]^irals or break-
ing up into rings, in consequence of the
expansion of the primary wall to which
they are attached,

SPIRAL STRUCTURES.

[ 711 ]

SPIRAL STRUCTURES.

It •will be convenient, in the first place,
to speak of the distinct well-marked struc-
tures ordinarily known as spiral cells and
vessels, occurring in tlie stems, leaves, &c.
of the higher plants, before describing cer-
tain other forms found in special organs,
and to reserve to the end some points re-
lating to the ultimate constitution of the
secondary membranes of cells. Spiral
structures are usually divided into true
spiral, annular, reticulated, and scalariform
organs.

Spiral cells and vessels are perhaps the
most generally difHised of the forms. The
name spiral vessel is given to elongated
cyhndrical cells tapering to a point at both
ends, with a spiral-fibrous deposit lining the
primary wall (fig. 669, and PI. 48. figs. 8, 11,
12). The spiral fibre may be either single,
as is most common, double (fig. 659) ; or

Fig. 659.

Fiff. 660.

Fig. 659. Fragments of spiral vessels from the Melon.
Magnified 200 diameters.

Fig. 660. Magnified diagram of a section of the base
of a leaf-stalk arising from a Dicotyledonous fhoot,
showing the position of the spii'al vessels in the leaf-
stalk and neit the pith of the shoot, the spiral fibres
being uncoiled and a little drawn out.

a number of fibres may run parallel {Mu-
sa, Nepent/ies, Zingiheracece, Marantacece).
These spiral vessels occur as the first vascu-
lar formation outside the pith (Medullary
Sheath) in almost all the Dicotyledons
(fig. 660), and as the first vascular forma-
tion in the vascular bundles of the stems of
Monocotyledons — also of all other vascular
bundles, forming the ribs or veins of pe-
tioles, leaves, bracts, sepals, petals, &c. In

the internal organs they can only be ob-
served in sections, or when extracted by
maceration : in delicate vessels and petals
they may often be observed tlirough the
transparent epidermis. The coiled spiral
fibre is mostly elastic enough to bear
stretching open like a wire S]iring ; m this
case the primary wall is torn between the
coils, and its ragged edges moy sometimes
be detected. The uncoiled fibres are often
seen still unbroken when a hyacinth or
similar leaf is broken across and the pieces
gently drawn apart. Ami ulur vessels closely
resemble the preceding, except that the
fibrous deposits are in the form of detached
rings (fig. 661) ; they are the rarest forms ;
they are especially remarkable in the Equi-
setacese. The reticulated, again, have irre-
gular spiral coils or rings connected more
or less by perpendicular or oblique bars
(fig. 662, and PI. 48. fig. 9) into a network.
These two modifications are usually of larger
diameter than the true spiral vessel, and
the reticulated larger (also of later origin in
the organs) than the annular. However,
mixed forms occur not uncommonly, partly
annular, partly spiral or reticulated (fig. 663).
They are found in similar situations, but
generally do not extend into the more de-
licate orgaiis. Spiral, annular, and reticu-
lated vessels may be prepared in most beau-
tiful forms and large size from portions of
the leaf-stalk of rhubarb, of the stem of the
garden-balsam, the melon, &c.

Fig. 661.

Fig. 662.

Fig-. 663.

Fig. 661. Fragment of an annular vessel from the
Melon. Magnified 200 diameters.

Fig. 662. Portion of a reticulated vessel from the
Melon. Magnified 200 diameters.

Fig. 663. Fragment of a spiral and annular vessel from
the Melon. Magnified 200 diameters.

Spii'al and other vessels are usually simple

SPIRAL STRUCTURES. [ 712 ] SPIRAL STRUCTURES.

at first (brauclied spiral vessels do occur,
more rarely), but ordinarily unite together
hj a kind of fusion. The conical extremities
overlap to a certain extent (fig. 659) ; and
thus the articulation is more or less oblique.
This fusion is much more evident and com-
plicated in roots, rhizomes, and abbreviated
stems than in stems with developed inter-
nodes. The elementary cells are then gene-
rally much shorter ; and the vessels formed
from them branch out in various directions
through the tissue. This is very well seen
in the roots of many herbaceous plants,
such as the dandelion, chicory, &c., and at
the point of origin of the vascular bundles
of adventitious roots generally.

The above-mentioned confluent spiral
vessels pass insensibly into the duds, which
are similar confluent rows of cells forming
parts of the sohd wood of stems, composed
of cells with flat ends applied together.
They may resemble in their markings the
preceding forms, but in their varied con-
ditions form a series leading towards the
Pitted Ducts. The scalariform vessels or
ducts (fig. 664, and PI. 48. fig. 10), so called
from the ladder-like markings, are a very
regular form of the reticulated type — this re-
gularity appearing to depend, however, upon
the relation between the markings of the ad-
jacent organs. In the Pitted DucTSwe find
the pits only opposite to other pits, therefore
on the .sides adj acentto other ducts or to cells ;
in the scalariform ducts
a spiral-fibrous deposit
is conjoined into a net-
work by vertical fibres
placed opposite the in-
tercellular passages or
the meeting angles of
contiguous cells or
ducts, leaving regular
slit-lilie spaces opposite
the cavities of the adja-
cent cells. This form
is especially charac-
teristic of the Ferns ;
but it occurs also com-
monly in the Dicoty-
ledons in a less regular

form, passing quite in- Fragments of scalariform

sensibly into Pitted vessels from a Fern.

DtrCT.S, as in the wood Magnified 200 diameters,
of Eryngium marithnum
(PL 48.' fig. 21). The scalariform vessels
of Ferns are often slightly luirollable.

It is mentioned under 1*itted Struc-
tures^ also, that a combination of the two

Fig. 664.

types sometimes occurs in the same cell,
'this is the case in the ducts of the Lime,
Mezereon, and other plants (PI. 48. figs. 4,
13, & 19).

Besides the generally diffiised spiral and
other vessels and ducts above described,
cells, properly so called (that is, such as
never become elongated very greatly in one
particular direction), belonging to particular
organs and plants, present the same kind of
mai'kings. The ducts and vessels, indeed,
in many cases are formed of vei-y short
cellidar elements ; but these may be distin-
guished from proper cellular tissue charac-
terized by spiral secondary deposits. Under
this head may be cited first certain wood-
cells. In the Cactacefe, the prosenchyma-
tous tissue of the stem presents remarkable
spiral and annular cells, in which the fibre
becomes so much thickened that it 2>rojects
like a riband set with its edge against the
cell-wall (PI. 48. fig. 7). The wood of the
Mistletoe (figs. 665,666) also exhibits spiral-
fibrous cells : that of the Yew (Taxus) is
composed of true spiral-fibrous cells and
others with bordered Pits and an internal
spiral fibre in addition (PI. 48. fig. 4). In
the stems of the Leguminosae, parenchy-
matous portions occur in the midst of the
wood, the cells of which exhibit spiral fibres
{Ulex, Sjxivtiuvi). The cellular tissue near
the surface of the roots of the epiphytic
Orcliids (PI. 48. fig. 6) affords another ex-
ample, as also some of the subepidermal
cells of the leaves "(fig. 667). The layers of

Fig. 665.

Fig. 666.

Fig. 667.

Fig. 665. Annular-fibrous cell from the stem of Mistle-
toe. Magnified 200 diameters.

Fig. 666. Cell intermediate between reticulated and
pitted, from the Mistletoe. Magnified 200 diameters.

Fig. 667. Spiral-fibrous cell from the leaf of an Orchid.
Magnified 200 diameters.

cells lining the Anthers of Flowering-
plants are characterized by most varied
patterns of spiral markings (PI. 40. figs. 1-5) ;
in these cells, moreover, we sometimes see
the connexion between the fibrous and ho-
mogeneous deposits well illustrated, as the
cells may have one or more sides marjved
with .spiral fibres, while the remainder of

SPIRAL STRUCTURES. [ 713 ] SPIRAL STRUCTURES.

tlie wall is covered -with a continuous layer.
A similar structure, generally with perfect
spiral fibres, occiu's in the walls of the spo-
ranges oiJungermannia, Marchaniia (PI. 40.
fig. 35), aud other Liverworts. With these
are nearly connected the structures called
Elatebs, which are found mixed with the
spores in the same plants. These are tu-
bular cells containing a single or double
elastic spiral fibre (PI. 40. _ figs. 36-38),
exactlj^ analogous to the spiral vessel in
structure. Elaters of similar nature occur
even among the Fungi, as in the sporange
of Teichia (PI. 40. figs. 39, 40). The ela-
ters of the Equisetaceae (fig. 205, p. 300)
are of different character, consisting of four
short filaments «-ith clavate ends, attached
at one side of the spore and originally
coiled round it, ultimately unrolling with
elasticity. They appear to be formed by
the deposition of a spiral-fibrous layer oh
the wall of the parent cell of the spore,
within which the true (single) spore-men-
brane is formed, unadherent ; and when the
spore is ripe, the spiral-fibrous layer splits
up and starts away from the inner coat.
An elegant spiral and annular fibrous struc-
ture is also met with in the large cells of the
leaves of the Sphagnace^ (PI. 48. fig. 25) ;
this is exactly analogous to the similar de-
posits in the higher plants. Spiral layers
are found, less distinctly, in the radical
hairs growing from the lower surface of the
frond of Marchantia. Nageli regards
them as folds of an inner layer of mem-
brane ; but they appear to be regular secon-
dary deposits.

Lastly, the hairs and sirnilar epidermal
appendages sometimes exhibit spiral-fibrous
deposits. An unroUable spiral fibre is
beautifully ai'ranged in the cells fonning
the mealy coating of the seed of Cohcea
scandens (PI. 28. fig. 20). The seeds of many
of the Acanthaceas (figs. 21 & 24), CoUomia
(fig. 22), the pericarp of some of the Labiatae
(fig. 23) and Compositas (Sexecio) bear
tubular hairs, consisting of cells with a spiral
or annular fibre in their interior (see H.-aRs
of Plants). The structure of the hairs of
CoUomia, Ruellia, &c. has been much dis-
cussed, but it seems very simple : they ap-
pear to consist of a short tubular cell, upon
the wall of which a closely coiled elastic
spiral-fibrous layer is deposited ; during the
ripening of the seed the primary membrane
undergoes a metamoi-phosis into a substance
related to amyloid (or bassorine ?), which
softens and swells up when placed in water,

allowing the spiral fibre to extend itself (PI.
28. figs. 21, 22 i, c). Sulpliuric acid and
iodine give the swollen gum-like envelope a
purplish tint.

Another and less distinctly marked spiral
arrangement of the substance of the cell-
walls occurs in the form of cracks or gaps
in certain of the layers of the secondary
deposits, ruiming more or less round the
cell, appearing like ireegular spiral streaks ;
these are sometimes present in the earlier
secondary layers and not in the later, so
that the " cracks " are covered in by the
latter and converted into canals in the sub-
stance of the cell-wall. These occur in the
wood-cells of Heniandia smiora, in the pros-
enchymatous cells of the vascular bundles
of Caryota urens, Phoenix, Metroxyhn, and
probably in other cases. Something similar
may be detected in the wood-cells of Pintis
(PI. 48. fig. 1), especially after treatment
with boiling nitric acid. In liber-cells a.
spiral texture is far more generally evident.
In Vinca, for instance (PI. 48. fig. 30), and
other Apocynaceous plants, a delicate spiral
striation of the wall is evident in its natural
state, beautifully regular in its arrange-
ment ; a similar appearance may often be
detected in the walls of thickened hairs,
especially when acids are applied, as in
Cotton (PL 28. fig. 1 J), particularly in gun-
cotton (fig. 1 c) — sometimes with interme-
diate slits, as in Urtica (fig. 8), &c. ; and
by boiling with nitric acid, a minute spiral-
fibrous structure may be detected in the
secondary layers of the liber-cells of very
many plants, as of Flax (fig. 2 b, c), Coir
(fig. 5 a, h), Boehmeria (fig. 25 h, c), &c.
All these spiral structures belong to the
secondary deposits of the cells ; they are
mostly distinguishable fi'om those previously
described by being thinner places or lines
left hare, instead of being lines of deposit.

' "We have observed a somewhat similar
spiral streaking of the walls of Hydrodictyon,
depending on slits in certain of the laminse.
Some of the genera of Oscillatoriacese, as
Ainactis (PI. 8. fig. 15 b) and Schizosiphon
(fig. 1-3 (?, e), also present a spiral-fibrous de-
composition of their cellulose coats when
old ; and we have seen a spiral marking on
the wall of Cladophora, as described by
Mitscherlich. Agaitlh has stated that he
detected a complicated spiral-fibrous struc-
ture in the cell-wall of Confervae, extending,
however, from one cell to another ; and he
regards this as a proof of the spiral sti-ucf ure
of primary cell-membrane generally ; and

SPIRAL STRUCTURES. [ 714 ]

SPIRILLUM.

says he has likewise detected an analogous
spiral-fibrous structure in the primary cell-
wall of the structures of the Phauerogamia.
The delicate striatiou of the membranes of
the Coufervfe and slightly thickened liber-
or pareuchyma-cells of many Flowering
plants form a desirable object of investiga-
tion for those accustomed to the delicate
observation of the markings of the valves of
the Diatomaceae. The use of reagents,
such as nitric acid and solution of potash,
boiling, maceration, and other means must
be employed for this purpose, controlled
always by a careful observation of the
structm-es in their natural state and in diffe-
rent stages of development. It is not im-
possible that all secondary deposits may
prove, as Mej-en assumed, to have a fibrous
constitution, and true memhi-ane to be con-
fined to the primary walls. One set of
layers, however, seems always to resist the
endeavour to resolve them into fibrils,
namely those of the horny and fleshy Al-
bumen of seeds.

As to the mode of the formation of spiral
secondary deposits, little is certainly known.
Criiger attributes them to spiral circulation
of the secreting protoplasm over the cell-
wall in the position of the future fibres ;
but this is a somewhat speculative notion.
Others have asserted that they are formed
by gradual collocation of visible granules ;
this is certainly an error. AVe have observed
the gradual formation of the spiral band
in the elater of Marchantia, where it is at
first a faint spiral trace with indistinct
edges ; as it grows thicker, the edges become
more and more defined ; and it is produced
originally in the exact position and pattern
which it subsequently retains.

The actively moving spiral filaments or
Spermatozoids of the Ferns, Mosses, Cha-
racese, &c. have nothing in common, ex-
cept the spiral form, with the structures de-
scribed in this article ; they belong to the
protoplasmic structures or cell-contents, as
is also the case with the spirally-arranged
green contents of Spirogyra ; while this
article refers exclusively to cellulose struc-
tures belonging to the cell-wall.

See also Cell, Vegetable ; Secondary
DEPOSITS ; Pitted structures ; and Tis-
sues, Vegetable.

BiBL. (Jeneral works on Vegetable Ana-
tomy ; Schleiden, Ann. N. H. vi. 35, 18-39 ;
E. Quekett, Tr. Mic. Soc. i. 1 ; Ann. N. H.
XV. 495 ; Mohl, Verm. Sckrift. 285, Ann. Sc.
Nat. 2. xvi. 242 ; Ve(/. Cell, 14 ; Agardh,

Cell. Vegetah. 1852; Criiger, Bof. Zeit. xii.
57, 833, xiii. 601 ; Casparv, Bot. Zeit. xi.
801 ; Tr^cul, Ann. Sc. Nat. 4. ii. 273 ;
Schacht, Pflanzenzelle, 1852 ; Bot. Zeit. viii.
697 ; Ungei", Linncea, xv. 385 ; Spencer,
Linn. Tr, xxv. 405 ; Hofmeister, Handh. Bot.
i. ; Sachs, Bot. 22.

SPIRILLI'NA, Ehr.— A doubtful genus
of marine Infusoria, of the family Arcellina.

Char. Shell siliceous, porous, forming a
flat spiral. »S'. vivipara. Shell microscopic,
hyaline, smooth, containing numerous em-
bryo shells. Foimd in America. (Ehren-
berg, Ahh. Berl. Ak. 1841, 402, 422.)

SPIRILLI'NA, Ehr., Rupt. Jones.— A
genus of Rotaline Foraminifera, near Pulvi-
nulina.

Char. Shell hyaline, consisting of a single
elongated chamber, coiled into a flat close
spiral ; orifice simple, as wide as the tube.

Two recent British species, *S'. perforata
(PL 24. fig. 5), and margaritifera ; also some
fossil (Jurassic and Tertiary).

BiBL. "Williamson, Bee. For. 91; Car-
penter, For. 180 ; Parker and Jones, Ann.
N. H. 4. iv. 386 ; ix. 221.

SPIRIL'LUM, Ehr.— A genus of Schizo-
mycetous Fungi.

Char. Consisting of a colourless, tortuous
or cylindrical spiral filament.

These very minute organisms, found in
infusions and decomposing liquids, are very
interesting objects on account of the re-
markable character of their corkscrew-like
movements. They multiply by transverse
division, separating into two portions while
in motion. They .are jointed or septate, but
the joints are not always easy of detection.
They are insoluble in boiling potash. Their
structure is best examined when they are
preserved in a dry state. They are appa-
rently related to the Oscillatoriaceous Algae,
but are very different from Spirulina, with
which thej' have been compared. Sjnril-
lum hryozoon consists of the spermatozoids
of Mosses.

Like the other Schizomycetes, they pro-
duce decomposition in organic liquids. A
species of ISpirochceta is supposed to be the
cause of relapsing fever, and occurs also in
certain purulent discharges.

*S'. tenue (PI. 7. fig. .17/). Filament
sliglitly tortuous, indistinctly jointed ; spiral
of three or four turns ; movement active ;
length 1-1000" ; diam. 1-12,000".

S. undula (PI. 17. fig." 17^). Filament
very tortuous, jointed ; spiral of oue or one

and a half turns ;

length

1-1500"; diam.

SPIROCH-ETA.

[ 715 ]

SPIROGYRA.

fij?. 23). Filaments
jointed, \ritli a

1-120,000". Perty describes a red and a
black variety.

S. rolutam (PI. 7. ^f,.
■s'eiy tortuous, distinctly
cilium at each end ; spiral of three, four, or
more turns; leng-th 1-1400" ; diam. 1-14,000".

S. plicatile (S/nroc/iceta jdicafilix, Ehr.)
(PI. 7. fig. 22). Filament very long, flexible ;
coils numerous : movement undulating ;
length 1-180"; diam. 1-12,000".

BiBL. Ehr. /«/. 84; Dujard. Inf. 223;
Rabenht. Ah/. ii."72.

SPIROCH^ETA, Ehr. — S. plicatilis =
SjnriUitm pUcatUe.

SPJROCHO'NA, Stein. — A genus of
Peritrichous Infusoria, family VorticelUna.

S. f/emntipara (PI. 32. fig. 3o) is found
upon the branchial plates of Gammanis
pulex, where also its remarkable Aoineta-
form (fig. 36) occurs.

S. ScJieidenii is met "with upon the feathery
setae arising fi-om the terminal joints of the
post-abdominal legs of Gammarus.

S. tintmnabulum, on Trifon-\&\'\Sd.

BiBL. Stein, Inf. ; Clap, et Lachm. Inf.
132: Kent, InfmO.

SPIRODIS'CUS, Ehr.— Under the name
S. fiilmis, Ehrenberg places among the In-
fusoria, in the family Vibrionia, a brownish
organism, consisting of a short discoidal or
much-flattened helical spiral, 1-1200" in
diameter, and found in Siberia. It exhi-
bited a slow movement. Ehrenberg's figure
gTeatly resembles that in PI. 40. fig. 34 (the
upper two), without the cilia, and magnified
200 instead of 400 diameters. (Ehr. Infus.
86.)

SPIROGY'RA (^Zyomma, Agardh in
part) (fig. 068). — A genus of Zygnemacese
(Confervoid Algte),
mostly very elegant,
and all very interest-
ing on account of their
structure and modes
of development. They
are green filaments,
floating imattached in
standing fresh water.
The}' consist of jointed
tubes — that is, rows of
cylindi'ical cells, some-
times of considerable
size, in the interior of
which the gr
louring-matter

Fig. 668.

is

co-
ar-

ranged in one or more
spiral lines running
roimd the walls, these

Sinrogyra communis.

Fragments of two

fllamonts conjugating.

MagniUed 200 diameters.

spiral lines presenting bright points at inter-
vals along their course (PI. 9. tigs. 17, 26, 27).
The green lines consist of bands of proto-
plasm coloured by chlorophyll. The bright
points are in some stages composed of
globules of similar substance ; but generally
they are occupied by starch-granules im-
bedded in the protoplasm ; smaller starch-
granules also occur at certain stages
throughout the green band. A remarkable
lenticular nucleus is also present, suspended
in the centre of the cell by threads of proto-
plasm running out to the primordial utricle
lying against the cell-wall. Sometimes this
nucleus is placed with its faces towards the
side wall {S. tiitida, PI. 9. fig. 26) ; sometimes
it appears to be placed with its faces
looking up and down, as it presents the
appearance of a narrow ellipse when seen
sideways (S. pelbtcida, PI. 9. fig. 27). The
laminated structure of the cell-walls is also
curious, but will be better imderstood after
a sketch of the mode of development.

The attractive appearance of the Spiro-
gyrce and the easily observed phenomenon
of conjugation have caused much attention
to be paid to this genus ; and maiiy points of
their history have been determined. The
cells composing the filaments all multiply
simultaneously when the plant is growing,
each becoming twice its length and divided
into two. It has been certainly observed by
Braun and Priugsheim that the division
is preceded by a division of the nucleus.
From this interstitial mode of growth it is
evident that the walls of the cells of plants
actively vegetating must soon become com-
posed of a number of layers belonging to di-
stinct generations of cells. Thus, supposing
we have an original cell a, this encloses its
progeny, two cells or kb; and when these
divide again and come to enclose respect-
ively a^ & c and V- & d, the parent cell a,
stretched to four times its original length,
still encloses the whole. The laminte be-
longing to the respective generations do not
become very intimately blended ; for by ma-
ceration we may cause the outer membranes
to soften and dissolve, and set free the
younger cells intact. The older membranes
seem to have become thinner by stretching,
or by solution, midway between their septa,
since on maceration we ma}' often see them
give way in the middle, and the young cells
slip out from them, leaving them as short
hyaline tubes with a diaphragm in the mid-
dle. The ends of the cells of some species
present a curious appearance, which might

SPIROGYRA.

[ 716 ]

SPIROGYRA.

be compared to the " punt '' of a bottle,
produced by a circnhtr fold thrown in from
the cross septum. It is attributed to the
excessive growth of the membrane of the
young ceUs, confined in space by the outer
pareut-membrane. The filaments of Spiro-
(jyra are consequently very instructive in
reference to vegetative cell-formation. In
some cases the half-dissolved parent-cell
membranes form a delicate but well-
defined gelatinous coat on the tube (PI. 9.
fig. 27 s).

Tlie reproduction of this genus exhibits,
besides the proper conjugation, other phe-
nomena, the import of which is not yet fully
determined. The conjugation itself has been
observed by almost every microseopist. It
consists essentially in the production of
papillary elevations on the contiguous walls
of the cells of two filaments lying side by
side, the growth of these papillae until they
come into contact, and their coalescence
so as to form a canal of communication be-
tween the two cells (fig. 668 ; PI. 9. fig. 18).
TMien this is accomplished, the contents of
one of the cells (the contents of both having
meanwliile lost their characteristic arrange-
ment on the cell-walls) pass thi'ough the
cross tube into the other cell, when the
contents of both become blended and form
an eUipitical free body (PI. 9. fig. 18), which
acquires cellulose integuments and becomes
a spore or zyr/ospore, lying free in the parent
cell. This process is accompanied by the
death of the parent filaments, conjugation
often taking place in the majority of the
cells : the spores are sometimes set free by
decay of the parent cell-wall ; but very often
the latter remains undissolved until the
germination of the spore (PI. 9. fig. 19).
A modification of this mode of conjugation
(PI. 3. fig. 24), occurs in some cases appa-
rently as an abnormal process ; for it has
been observed ( Braun) taking place in species
which conjugate as above. It occurs in single
filaments in which two contiguous cells
produce papill.ie at the adjoining ends,
growing towards each other and coalescing,
the contents of one of the cells thus passuig
into the next cell of the same filament.
Braun calls this "chain-like" conjugation,
in contradistinction to tlie " ladder-like " |
conjugation above described. As the two j
forms occur associated, Kiitzing's genus
Rhynclio7iema and others fomided upon this
are of doubtful value.

The ripe spore or zygospore forms an
elliptical body enclosed in three membra-

nous coats, the outer of which is of deli-
cate texture and separated by an interval
from the next, which is brownish and of
fu'm texture. The inmost coat or true
spore-membrane, is again delicate. The
spores appear to rest through the winter
after they are formed, and to germinate in
spring, in which process the middle coat
of the spore splits at one end, longitu-
dinally, opening by two valves to allow the
inner to gi-ow forth, which bursts through
the outermost sac, in the form of a tube
(PL 9. fig. 19) which soon acquires the
characteristic appearance of the parent
plants. The contents of the spore are brown
and homogeneous during the stage of rest
(fig. 21) ; in germination they become green
again, and arrange themselves iu the spiral
bands (fig. 22), which become more distinct
as the cell elongates.

Certain other occurrences take place in
the cell-contents of the Spirogyrce, the rela-
tion of which to the reproduction is not so
clear as the above. In filaments in an un-
healthy condition, about to decay, such as
are often seen when a collection of them is
placed in a jar of water to keep for exami-
nation, it is not uncommon to see the green
contents gradually lose their spiral arrange-
ment and break up into a number of globular
portions (PL 9. fig. 28) ; we have sometimes
observed these rolling over slowly in the
cell. In one case we have observed the
contents converted into sixteen distinctly
organized biciliated zoospores (PL 9. fig. 20),
differing only from tlie ordinary zoospores
of the Confer\-oids in the almost total
absence of colour. They were somewhat
crowded iu the cell, and moved lazily about
in it, the cilia vibrating. It is still more
common to observe the contents of decayed
filaments convei-ted into encysted globules
(PL 9. figs. 24, 25), which appear to be
a kind of resting-form of the zoospores.
These globules, which have a tough spiniilose
coat, have been observed by Pringsheim
as produced from the contents both of
ordinaiy cells, and abnormally ? from the
contents of a large spore (PL 9. fig. 23) : the
latter case might give colour to the idea that
this was a sporange, had not its germination
been observed. Pringsheim has furtlier
noticed that actively moving zoospores are
produced from the small encj^sted bodies ;
perhaps these may fulfil an antheridial
function. Carter has observed in the cells
of Spiroyi/ra the bodies constituting the
genus PytJmim, and apparently coonected

SPIROGYRA.

[ 717 ]

SPIRORBIS.

witli the zoospore-like bodies just described
(see PYTunjM).

The species of Spirof/i/ra have been
p-eatly multiplied by author.*. The pecu-
liar fold projecting from the septum appears
to us to depend upon age and activity of
growth ; and the length of the joints de-
pends greatly on the stage of growth, as
they continually divide into two equal parts.

Spiral band single.

S. tenuissima. Vegetating filaments 1-3000"
in diam. ; joints four or live times as long
as broad ; spiral band open ; spore oblong-
elUptical (Hassall, pi. 32. figs. 9, 10).

S. Ivmiata. Filaments about 1-1000" in
diam. ; joints six or eight times as long ;
spiral lax, spores oblong-elliptical (Hass.
pi. 31. fig. 394).

*S. injlata (S. (/astroides, Kiitz.). Fila-
ments 1-1680" in diam. ; joints four or five
times as long ; turns of spiral about five ;
fertile cells ventricose ; spores oblong-
eUiptical (Hass. pi. 32. figs. 6, 7).

<S'. commttnis (fig. 668). Filaments 1-1440
to 1-2000" in diam. ; joints two or three
times as long ; turns of spiral four, broad ;
spores elliptical (Hass. pi. 28. figs. .5, 0).

S. quinina (PL 9. fig. 17). Filaments
1-600" in diam. ; joints once and a half or
twice as long ; tiu-ns of spiral broad and
dense ; spores elliptical (Hass. pi. 28. fig. 2).
Varies in the length of the joints, which are
sometimes twice to seven times as long.

Spiral bands two.

S. decimina. Filaments 1-720" in diam. ;
joints two to fom- times as long; spiral
bands lax, crossing so as to present the
appearance of the letter X (Hass. pi. 23.
figs. 3, 4).

S. elongata. Filaments 1-1320 to 1-1200"
iu diam.; joints ten times as long; bands
lax (Berkeley, Gleanings, 12, fig. 2).

Spiral bands numerous.

S. nitida (PL 9. fig. 26). Filaments
1-360' ' in diam. ; j oints twice or three times
as long ; bauds fom-, dense, closely veiled ;
spores elliptical (Hass. pi. 22. figs. 1, 2).

S. maxima. Filaments 1-200 to 1-300"
in diam. ; joints equal, once and a half or
twice as long ; bands lax : spores globular
(Hass. pk. 18, 19).

S. bellis. Filaments 1-400"; joints equal
or twice as long ; bands two or three, lax ;
spores roimded; var. /3, spirals condensed
(Hass. pi. 24).

S. pellucida (PL 9. fig. 27). Filaments
1-840" in diam. ; joints four or six times as
long ; bands lax and slender ; fertile cells
ventricose ; spores globose (Ilass. pi. 2.5).

S. rimdaris. Filaments 1-2040" in diam. ;
joints three or four times as long; spiral
bands four, broad, dense (Hass. pi. 27).

<S'. curvatum (Sirogonimn stictituni and
breviarticulatum, Kiitz.). Filaments 1-720"
in diam, ; joints four or five times as long ;
bands three or four, slender; conjugation
dii'ect, without a cross branch, approaching
Mougeotia. (Hass, pi. 26. figs. 1, 2.)

BiBL. Hassall, Alg. 135 ; Kiitzing, Sj).
Aig. 437, Tab. Phyc. v, ; Pringsh. Flora,
XXXV. 465, Ann. N. H. 2. xi. 210; Brauu,
Verjiingimg, Hay Soc. ; Vaucher, Conferves,
37 ; Agardh, Ann. Sc. Nat. 2. vi." 197 ;
Rabenh. Ah/, iii. 232 ; Carter, Ann. N. II.
1880, vi. 207 ; Petit, Srnrog. of Paris,
1881.

SPIROLI'NA, Lamk. (Spirulina, Ehr.).
— -Restricted. The long, narrow, crozier-
like modifications of Peneroplis (P. (Sp.)
austriaca, PL 23. fig. 12) come under this
title. Fossil and recent.

BiBL, D'Orb. For. Foss. Vien. 137 ; Car-
penter, Phil. Tr. 1859, 10 ; Parker, Jones,
and Brady, Ann. N. H. 3. xv. 230.

SPIROLOCULI'NA, D'Orb, — A sub-
genus of Miliola, among the Porcellaneous
Foraminifera,

Clucr. Shell regular, equilateral, com-
pressed, oblong, oval, or elongated ; cham-
bers concentric on two opposing faces, in the
same plane, not embracing, all apparent and
with simple cavities ; orijice single, situated
alternately at the two ends of the longitu-
dinal axis, simple or with a tooth, frequently
prolonged into a tube.

Sp. planalata (PL 23. fig. 7). Many
species, recent and fossil.

BiBL. D'Orb. Ann. Sc. Nat. vii. 298;
Williamson, Rec. For. 82 ; Carpenter, For.
77 ; Parker, Jones, and Brady, Ann. N. H.
4. viii. 248.

SPIROM'OXAS, Perty.— A genus of
Flagellate Infusoria.

Char. Body leaf-like, compressed, rounded
at both ends, and loUed spirally ; with one
or two flagella.

S. vohibilis=Cycliditim distortum, Duj.
Kent describes other species, (Pertj'-,
Lebensf. 171 ; Kent, Inf. 297.)

SPIROPLEC'TA, Ein-. See Textulaeia.

SPIROR'BIS, Daudin, Lamk,— A genus
of AnniUata, order Setigera,

The elegant little milk-white flat spiral

SPIROSTOMUM.

[ 718 ]

SPLACHNACE^.

shells of S. naittiloides {communis) (PI. 36.
fig. 29) are frequently met with upon Fitcus
sen-atus, &c. The animal has six pinnate bran-
chial filaments and a pedunculate operculum.
SPIROSTOMUM, Ehr. — A genus of
Heterotrichous Infusoria, family Bursarina.

Char. Body ciliated all over, oblong or
cylindrical and elongated, or flat ; mouth
spiral, with neither teeth nor a tremulous
lamina ; anus posterior ; fi'eshwater.

S. amhiguiim (PL 81. figs. 77. 78). Body
cylindrical and elongated, colomless, ob-
tuse in front, truncate behind, prolonged
anteriorly beyond and above the mouth ;
length 1-12".

S. teres. Body lineai'-fusif orm ; length 1-60' '.
BiBL. Ehi-. Inf. 332 ; Dujard. Inf. 514 ;
Clap, et Lach. Inf. 231.

SPmOT^'NIA, Breb. — A genus of
Desmidiaceee.

Char. Cells single, elongated, cylindiical
or fusiform, straight, entire, not constricted ;
endochrome spiral.

Division oblique. In one species the
endochrome is spiral at first, subsequently
becoming uniform.

S. condensata (PI. 14. fig. 59). Endo-
chrome forming a single broad band ; length
1-208'' ; common.

S. ohscnra. Endochrome at first forming
several spiral threads, afterwards uniform ;
length 1-240".

BiBL. Ralfs, Desmid. 178 ; Archer, Qu.
Mic. Jn. 1867, 186 ; Rabenhorst, Alg. iii.
145.

SPIRULI'NA, Link.— A genus of Oscil-
latoriaceffi (Confervoid Algse), consisting of
minute spirally coiled geeen filaments im-
mersed in a colom-less gelatinous matrix,
and having an oscillating motion ; forming
extensive strata in lakes, brackish water,
&c. The intimate structure and develop-
ment of these curious organisms are not yet
well understood; they are supposed to
increase by the filaments breaking across :
in some the filament appears continuous;
in others it has striaj, like the Oscillator ics,
appearing beaded when badly defined.

*S'. Jennei-i (PI. 7. fig;. 16). Filaments
with strise, 1-6000" in diameter, usually of
eight or ten coils, forming a thin teruginous
stratum.

»S'. oscillarioides (PI. 7. fig. 15). Fila-
ments not striated ; coils 1-7200" in diam. ;
lax. Among Oscillatorice in stagnant pools.
BiBL. Kiitzing, Sji. Alg. 236; Hassall,
Alg. Til, pi. 75 ; Harvey, Mar. Alg. 229,
pi. 27 ; Phyc. Br. pi. 105 ; Ralfs, Ann. N.H.

xvi. 308, 2. viii. 205; Cohn

Nova Acta,
XXIV. ; Rabenht. Alg. ii. 90.

SPLACHN A'CE^.— A family of Funa-

rioideas (Acrocarpous operculated Mosses),
of broad and densely tufted habit, mostly
found upon dung, with a very much branched,
loosely-leaved stem (fig. 669). Inflorescence
hermaphrodite, dioecious, rarel}' monoecious.
Antheridial flower a capituliform, terminal
bud. Antlieridia large, club-shaped, rather

Pig. 669.

Fig. 670,

Splachnum vasculosum.

Fig. 669. Nat. size.

Fig. 670. Eipe capsule open, dried, and the apophysis
shrivelled. Magnified 20 diameters.

Fig. 671.

Fig. 672.

Fig. 673,

Splachnum vasculosum.

Fig. 671. Calyptra. Magnified 20 diameters.

Fig. 672. Young capsule and apophysis. Magnified
20 diameters.

Fig. 673. Vertical section of an unopened capsule mth
its spongy apophysis. Magnified 20 diameters.

cm'ved, Archegonia narrow, long-apicu-
late. Peristome, if present, of regulaily

SPLACHNAOEaE.

[ 719 ]

SPLEEN.

lanceolate, neither obtuse nor trabeculate,
twin, nifescent, rather fleshy teetli. Coki-
mella ordinarily projecting (fig. 670). Cap-
.<ule on an apophysis (fig. 673), mostly fur-
nished with stomates.

British Genera.

CEdipodium. Calyptra soft, longish-nar-
row, split almost to the summit, obtuse,
somewhat lacerated at the base. Capsule
subglobose, loosely reticulated, soft, with a
very long collum arising from a gradually
thickened fruit-stalk, the mouth naked.
Columella dilated at the apex. Inflores-
cence monoecious.

Tetraplodon. Calypti-a smalUsh, hood-
shaped, split to the middle, operculate,
delicate. Capsule apoph^^sate, oval-cylin-
di'ical. Apophysis obconical, obovate, or
subovate. ColumeUa scarcely dilated at
the apex. Peristome of sixteen double teeth
in fours, lanceolate, formed of two rows of
cells, connate in pairs at the base, refiexed
when diy, erect and incurved when moist,
much shorter than the capsule. Autheridial
flower sessile in the axil of a leaf, or termi-
nal on a little special branch, in a capituli-
form bud.

Tayloria. Calyptra inflatedly conical,
erect, split at one side, constricted at the
base, lacerated aroimd the margin. Peri-
stome arising below the orifice of the cap-
sule, of sixteen or thirtj^-two teeth ; teeth
single, approximated in pairs or coherent,
often very long ; when moist incurved and
involuted, when diy (in the ripe capsule)

Fig. 674.

reflexed, appressed to the capside or tortu-
ously bent down; very hygroscopic. Inflo-
resceuce monoecious. Columella mostly
free, exserted from the ripe capsule, flattish-
apiculate.

Dissodon. Calyptra inflatedly conical,
erect, slit at one side, constricted at the
base and torn or erose. Peristome arising
at the orifice of the capsule. Teeth thirty-
two, connate, in eight bigeminate or sixteen
geminate teeth, lanceolate, smooth, trans-
versely articulate, connivent into a depressed
cone when moist, subincurved when dry.
Inflorescence perfect or monoecious. Colu-
mella included or exserted, flatfish. ■

Splachmim, Calyptra conical, rather
small, entire or slit here and there at the
base. Peiistome of sixteen teeth, composed
of a double row of cells, lanceolate, largish,
yellowish, approximated in pairs and to
some extent conglutinated, when dry re-
flexed and appressed to the capsule, when
moist erect and incurved at the apex. In-
florescence diojcious, rarely monoecious.
ColumeUa ordinarily emerging, capitate.

SPLACHNUM, Linn. — A genus of
Splachnaceae (see above). >S'. aonjyullaceum
is not uncommon on the dung of animals on
bogs, is a very handsome moss, with purple
or red capsules. S. vascidosum (figs. 6G9-
673) is less common, occurring only in high
mountain districts.

SPLEEN. — This organ appears to occur
exclusively in the Vertebrata, but is not
found in the Leptocardia and Myxiuoids.
The spleen is covered externally by the

Fig. 675.

Fig. 676.

Fig. 674. Natural size. Portion from the middle of the spleen of an oi, washed ; showing the bands and their
arrangement.

350

Fig. 675. Peculiar fibres from the pulp of the human spleen, belonging to the microscopic trabeculse. Magnified
diameters.

Fig. 676. One of the same enclosed in a cell. Magnified 350 diameters.

SPLEEN.

[ 720 ]

SPLEEN.

peritoneum, except at the hilus, where the
vessels are connected with it.

Beneath the peritoneal tunic is a thin,
semitransparent, firm, fibrous coat, which at
the hilus accompanies the vessels, and forms
sheaths around them.

The spleen is traversed hy fibrous bands
or trabeculse (fig. 674), which arise from
the inner surface of the fibrous coat and
from the outer surface of the vascular
sheaths, and, being- connected with each
other, form a number of irregular meshes
or areolae, in which are situated the splenic
corpuscles and the spleen-pulp. In reptiles
they form stellate expansions, their connec-
tive tissue becoming infiltrated with lymph-
corpuscles; and the connective tissue in
this modified form occupies all the inter-
spaces of the proper parenchyma of the
organ.

The fibrous coat and the trabeculse consist
of ordinary connective tissue, with mostly
parallel fibres, traversed by networks of fine
elastic fibres, which become continuous with
the coats of the veins. In certain animals,
as the dog, cat, pig, &e,, the fibrous coats
and trabeculse contain also unstriped mus-
cidar fibres. These do not occur in man,
unless they are represented in the micro-
Fig. 677.

scopic trabeculse by pecidiar wavy fibres,
about 1-500" in length, with lateral or
stalked nuclei (fig. 67o). Some of these
are found enclosed in cells (fig. 676), from
which they become liberated by the action
of water.

The splenic or Malpighian corpuscles
(fig. 677) are white rounded bodies, imbed-
ded in the spleen-pulp, and attached to the
smallest arteries. They vary in size from
1-120 to 1-36", and cannot always be de-
tected. They are either placed upon the
sides of the arterial branch, or situated in
the angles of their bifurcation.

The splenic corpuscles consist of an enve-
loping membrane (fig. 678 a) composed of
connective tissue with fine reticular elastic
fibres, and derived from the arterial sheath.
They are traversed by capillaries and filled
with a tenacious grey parenchyma. The
parenchyma consists of cells 1-3000" in
diameter, containing one or two nuclei, and
free nuclei (fig. 104, p. 138). Sometimes
the cells contain globules of fat or blood-
corpuscles ; and occasionally free blood-cor-
puscles are met with. When the splenic
corpuscles undergo amyloid degeneration,
they produce the so-called sago-spleen.

"The splenic pulp forms a soft reddish

Fig. 678.

Pig. 677. Portion of a smaO artery from the spleen of a dog, with one of the branches covered witli Malpighian
bodies. Magnifii'd 10 diameters.

Fig. 678. Malpighian corpuscle from the spleen of an ox. «, wall of the corpuscle; b, contents; e, wall of the
artery upon which it is situated ; d, its sheath. Magnified 150 diameters^

SPOLVERINA.

[ 721 ]

SPONGIDA.

mai^s, and consists of three elements — micro-
scopic trabecule, fibres, or bands, parenchy-
ma-cells, and the smaller blood-vessels — or
of cells and an intercellular substance. The
trabecuhv agree in structm'e ^^ ith the larger
ones. The tibres or bands are the termina-
tions of the sheaths of the vessels ; they are
indistinctly fibrous, and free from elastic
tissue. The parenchjona-cells resemble
those in the splenic corpuscles. Blood-cor-
puscles are found enclosed in cells, from
one to twenty in each, or surrounded by a
transparent substance, their contents exhi-
biting vai'ious changes in colour and con-
sistence. The arteries tenninate in elegant
tufts or peuicilli, becoming continuous with
a meshwoi-k of capillaries.

The blood-corpuscles from the blood of
the splenic vein frequently contain crystals
of hsematoidine.

In the examination of the spleen, the tra-
beculse aie best seen after washing away the
pulp with water, the splenic corpuscles by
tearing the spleen or boiling it, either in
the pig or ox. The cells containing blood-
coi-puscles must be searched for in the pulp
unacted upon by water. The muscular fibres
are most evident in the smaller trabeculse,
especially after treatment A\'ith dilute nitric
acid (one part to five parts of water).

BiBL. Koliiker, Mik, An. ii. and Todd's
C'ljcl. An., art. Spleen ; Gray, A, Cooper^s
Prize Essay ; Saunders, Goodsir^sAnn.ofAn.
1851, i. ; Huxley, Qii. Mic. Jn. ii. 1854 ;
Frey, Mikros. ; Miiller, Strieker's Hist, and
the Bibl. therein.

SPOLVERI'NA, Mass.— A genus of
ilicro-hchens, parasitic on the thallus and
prothallus of various crustaceous lichens.

Char. Spores 1-2, large, globose-ovoid,
simple, colourless, or yellowish. (Lindsay,
Qu. Mic. Jn. 1869, 344.)

SPONDYLOCLA'DIUM.— A genus of
Dematiei ( Ilyphomycetous Fungi), analo-
gous to Arthrobotryum, characterized by the
erect filaments, with whorled multiseptate
spores (PI. 27. fig. 15j. (Mart., Fl. erl. 354 ;
Link, Spec. 79 ; Hotixaann, Fl. germ. ii.
pi. 13.)

SPONDYLOM'ORUM, Ehr.— A genus
of Volvocinese.

S. quaternarium. Ccenobium globose,
compoj^ed of 8-12-10 cuneata green cells,
each with a long cilium, and a dorsal red
eye-spot, enclosed in a colourless gelati-
nous envelope (PI. 3. fig. 23). In ditches.
(Pertv, ie6e?2.s/'. 177; Rabenht. ^/y. iii. 98.)

SPONGASTERIS'CUS, Hckl.— A genus

of Radio-flagellate Infusoria, with a silice-
ous perforated carapace. 2 species; marine,
(Kent, Inf. 229.)

SPON'GIDA or PORIF'ERA.— A Class
of Protozoa.

Char. Form variable ; fixed by a kind of
root at the base, or incrusting ; consisting
of a soft gelatinous sarcodic mass, mostly
supported by an internal skeleton, composed
of reticularly anastomosing horny fibres, in
or among which are usually imbedded sili-
ceous or calcareous spicida ; or sometimes
the spicula alone form the skeleton.

The horny fibres forming the skeleton of
sponges, which may be well seen in any
common sponge, are cylindrical, and vari-
ously united, so as to form a coarse network
with roundish or angular microscopic meshes,
In addition to these generally diftused
meshes or intervals, large (to the naked
eye) rounded apertures or oscula are scat-
tered over the surface of most sponges,
leading into sinuous canals permeating their
substance in every direction ; and between
these are other smaller apertures, just visi-
ble to the naked eye, also the orifices of
canals, which traverse the substance and
communicate with the oscular canals.

In the Hving sponge, this skeleton is
covered with a glairy or gelatinous, colour-
less, amorphous substance, resembling that
of which Amoebce are composed; the
proportion being variable in the different
genera. This substance appears to be
composed of minute masses, those on the
smfaces being furnished ^vith a long and
slender flagellum, or forming collared
monads ; and during life, by means of these,
water entering by the smaller apertures,
and reaching the oscular channels, is ex-
pelled from the oscula in ciu-rents, which
may be rendered visible by sprinkling a
little finely powdered charcoal over them.
Hence Clark and Kent refer the Sponges
to the Choano-flagellate order of the Infu-
soria.

The fibres of the common Sponges appear
to be solid under the microscope ; and when
treated with sulphuric acid, they are seen to
consist of two parts, an outer tubular portion,
which is contracted in length by the acid,
and an inner cylindrical thread, which
usually becomes elegantly wavy or spiral,
frequently protruding from the cavity of the
outer portion in broken fibres, and resem-
bling PI. 28. fig. 22.

The spicula are of various forms (PI. 46,
lettered figui'es), and either scattered through

3a

SPONGIDA.

[ 722 ]

SPONGOCYCLIA,

the substance or arranged in bundles form-
ing spurious fibres; sometimes projecting
more or less from the surface (PI. 45. fig. 8).
In some sponges they are absent, and in
one genus tliey are replaced by gravel. The
calcareous spicula exert a much more
powerful action upon polarized hght than
the siliceous spicula.

In some sponges, an external membrane
is present ; and this has been observed to
exhibit a reticular or cellular appearance,
from the presence of fine reticular fibres.

Sponges are mostly marine, rarely fresh-
water. In the natiu'al state they often
possess lively colours, which appear in some
instances to arise from the presence of gra-
nules of colouring matter, probably chloro-
phyll, in others from iridescence. They
usually grow in groups upon rocks, shells,
zoophytes, sea-weeds, &c.

Sponges appear to be propagated in four
ways : — by gemmation, from the interior of
the canals ; by the formation of ciliated gem-
mules (swarm-spores) ; by the formation of
true sexual ova ; and by the production of
bodies analogous to " winter-ova."

The ciliated gemmules,

which are not of
are yellowish, oval,

general occurrence,

narrowed at one end, and covered, except
at this part, by vibratile cilia. They are
mostly formed in spring, and after swim-
ming about for a time, become fixed to some
suitable spot and undergo development.

Of the other reproductive bodies, one
kind consists of roimdish or ovate masses
containing spicula and resembling the
parent in structure, either lying loose in its
substance, or adherent to the horny fibres,
and escaping at its death and solution, to
acquire maturity.

The " winter-ova " are round or ovoid
seed-like bodies, with a fumiel-shaped de-
pression on the surface communicating with
the interior. At first these lie in a ca^ity
formed by condensed surrounding substance ;
subsequently a membrane presenting a hex-
agonal reticular structure is formed aroimd
tht-m, upon which a crust of spicula is
afterwards deposited. When expelled from
the body of the parent, they are motionless;
they then swell up, burst, and the mimite
locomotive germs escape. These exhibit
Amacba-Mke processes, and take on an inde-
pendent Hie.

The true ova are oval, and scattered
through the general substance ; they have a
distinct outer membrane, with a germinal
vesicle and spot. The spermatozoa have

an oval body and a filament ; thej' occur in
minute cells, also difiused through the sub-
stance. The germs are ciliated.

Sponges are probably nourished by en-
closing Algae &c. in their substance in the
same manner as Amabce. This has been
seen to take place in the young animals
developed from the winter-ova.

According to the skeleton, the sponges
are divided into three Orders : My.vospon-
gi(Sy in which it is absent (Halisarca); Fihro-
sponr/ice, in which it is horny or siliceous ;
and Calcispouffice, in which it is calcareous.

Thread-cells have been found in the
genus Reniera ; and Eimer states that he has
even distinguished in some siliceous forms
something like connective tissue and fusi-
form muscular fibres.

BiBL. Johnston, Br. Sponges ; Bowerbank,
B)\ Spong., Ray Soc. 1866; Huxley, Comp.
Anaf.; 3&viQS,-(M?ivk, Amer.'Jn.of Sci.\S71 ;
Gray, Pr. Roy. Soc. 1867 ; Lieberkiihn,
Miiller's Archiv, 1856, Ann. N. H. 1868, ii.
236; Thomson, Phil. Tr. imQ,nn^ Deep-sea
Drechjing ; Ellers, Sieh.uiid Kdll. Zeit. 1871,
xxii. 540; Eimer, Sehultze's Arch. 1872;
Leidy, Amer. Nat. 1870 ; Agassiz, Bull.
Harvard Coll. 1869 ; Miklucho-Maklay,
Mem. Acad. Petersboiirg, 1870 ; Schmidt,
Spongienfauna Allan. Geb. 1870 ; Spong.
Kiiste Algier, Spong. d. Adriat. Meer. ; Car-
ter, Ann. N. H. 1878, ii. 157 ; ib. 1879, iii.
284, 343 ; ib. 1879, iv. 374 ; Gosse, Mar. Zool.
i. ; Haeckel, Kalkschivihnine, 187 S ; Vosmaer,
Broun, Klass. Sfc, 1882 ; Kent, Inf. 143.

SPONGIL'LA, Lam.— A genus of fresh-
water sponges. Two British species, S.
fluviatilis and S. laciistris.

Found attached to stones, old woodwork,
&c. in still or slowly running waters ; gi'een
or grey. See Spongida.

SPONGIOLES.— Many works on vege-
table physiology still retain the old error
that the extremities of roots are devoid of
epidermis, and that the tissue then presents
an open spongy character, whence the name
of spongioles applied to the absorbing apices
of roots. So tar is this from being a correct
account of the conditions, that, in reality,
not only is the surface completely invested
with a continuous epidermis, but the grow-
ing point and principal absorbing surface is
found a little above the absolute extremity,
which is pushed forward b}' interstitial
growth (fig. 679). See Roots.

SPONGOCYC'LIA; Hckl— A genus of
Radio-flagellate Infusoria. Several species ;
marine. (Kent, Inf. 228.)

I

SPONGOMONAS.

[ 728 ]

SPORENDONEMA.

Fig. 679.

Longitudinal section of the rootlet of an Orchjs.

C, C, Cellular tissue (cambium) in which development
is still going on. FP, Fibro-vascular bundles gradually
becoming organized from above downwards.

Magnified .500 diameters.

SPONGOM'ONAS, Stein.— A geuus of
Flagellate lufiisoria. Ovate or rounded ;
flagella two, equal ; immersed in a gelati-
nous envelope. Four species ; freshwater.
(Kent, Inf. 286.)

SPORAN'GIUM and SPOR'OCARP.—
The term sporangium is applied to the
structure immediately enclosing the spores
of the Cn-ptogamia. The different forms
and conditions are described under the
classes of Flowerless plants. Abortive spo-
rangia in Ferns, sometimes borne on the
pedicel of the true sporangia, are called spo-
rangiastra. Sporocarp or spore-fruit is the
name given to the capsules or similar organs
which contain the sporanges of the Mar-
sileaceae (see Pilulabia).

SPOREXDONE'MA, Desm. — A sup-
posed genus of Sepedoniei (more properly
belonging to Saproleguese). It is a very
common occurrence in autumn to find the
house-fly, dead, adhering to walls, window-
panes, &c., firmly fixed by its probo.scis,
and with its legs spread out, thus differing
from dead flies in general, which have the
legs contracted. In about twenty-four
hom's after death, a kind of fleshy substance
of a white colour, is found in the form of a
ring projecting between each of the rings,
of the abdomen ; and in a day or two after,

the whole will be found dried, and the
surface of the wall or glass lightly covered
in a semicircle, at about 1-2 to 1" from the
fly's abdomen, with a cloud of whitish
powder. The whitish fleshy sub.stance is
found on examination to consist of a vast
number of short erect filaments growing
out from the interior of the fly's body, be-
tween the rings ; these filaments contain
large oil-globules, often arranged in a row ;
and their having been mistaken for spores
gave origin to the name Sporendonema
applied to this fungus. Cohn has described
its growth somewhat minutely, and chan-
ged the generic name to Empusa, or rather
Empusina, the first of these names being al-
ready occupied. He correctly states that
the vertical filaments terminate in the ab-
domen in a continuous, often branched
tube, and consist therefore of a single tubu-
lar cell. The upper free end, however, be-
comes cut off by a septum ; and the terminal
cell acquires a campanulate form and a
darkish colour ; when ripe, it is thrown off
with elasticity ; and a number of these form
the white cloud above mentioned. Cohn
endeavom-ed in vain to make them germi-
nate ; and nothing like them was found in
the cavity of the abdomen of numerous
flies in which the filaments were traced in
their earlier stages. From our own obser-
vations, we rather incline to regard them as
peridioles or spore-cases, comparable perhaps
to that of Piloholus ; or they may be stylo-
spores, like some of those of the Uredinei,
which after a stage of rest produce an inter-
mediate mycelial structure, and then give
birth to the ripe spores.

The most remarkable point about this fly-
fimgus (to which, however, Cohn does not
allude) is the circumstance that, when the
body of the fly with the rings of fungi
freshly developed is placed in water, Achlya
proJifera is almost always, if not always,
produced, and apparently from the filaments
which in the air produce the bell-shaped
deciduous body above described. We find
the Achilla with its ciliated zoospores, and
later with its globidar .sporanges filled with
spores, apparently representing an aquatic
form of the Sporendonema or Empiisina.
Cienkow.ski has recently confirmed the view
that Achlya is an aquatic form of the present
plant, but Braun denies this ; he states that
he has found a second species of Empiisina
on the common gnat (Cukx pipiens).

Sporendonema Casei, Desm., is referable

to TOKULA.

3a2

SPORES.

[ 724 ]

SPORES.

ley,

XXV.

2. V.

BiBL. Berk. Br. Fl. ii. pt. 2. 350 ; Fries,
Syst. Myc. iii. p. 435, Sum. Veg. 594 ; Var-
Tr. Mic. Soc. iii. ; Colin, Nova Acta,
299 ; Berk, and Broome, Ann. JV. H.
4G0 ; Oieukowski, Bot. Zeit. xiii. 801 ;
Brauu, Aly. Unicell. 105.

SPORES, Spobules, Sporidia, Spori-
DioLA, Microspores, Macrospoees^ &c. —
A number of nearly connected terms which
are applied to the various organs which
either really or apparently represent, in the
Flowerless Plants, the seeds of the Flower-
ing classes. The names have been mostly
applied with the view of marking slight
distinctions between organs supposed to be
homologous. Of those placed at the head
of this article, the first only should be
retained, the second being merely a useless
diminutive of it, and the third and fourth
being superseded by the more definite no-
menclature now applied to the reproductive
bodies of the Cryptogamia.

It may be desirable perhaps here, if merely
for the sake of explaining the exact meaning
of words constantly used in this work, to
pass in review the various structures com-
prehended under the general name of
Spore.

The definition of the word spore itself, as
commonly used, may be stated thus : — a re-
productive body, thrown ofl^ by a FloAverless
plant to reproduce its kind, and containing
no embryo at the moment when cast oft' by
the parent. It is evident from this how lax
is its application.

The highest of the Flowerless plants, the
Marsileacese and the Lycopodiacese, produce
two kinds of spore — one destined to produce
spermatozoids, the other archegonia and
ultimately embryos growing up into new
plants. These are sometimes distinguished
as pollen-spores and ovule-spores or oospores ;
the latter are large sacs with complicated
outer membranes, the former simple cells
with a double coat, like pollen-grains (see

PiLULARIA, IsoiiXES, and LYCOPODIACEiE).

The Ferns and the Equisetacese produce
only one kind of spore, a simple cell with a
double coat, the outer of which is generally
elegantly marked in the former (tigs. 232-
236, p. 321), and split up into elastic fila-
ments or elaters m the latter (tig. 205,
p. 300). In germinating, tliis spore pro-
duces a kind of thallus, the prolhallium
(figs. 23G-239, p. 321), on which antheridia
and archegonia ultimately appear, and an
embryo is formed, fertilized, and developed
(see Ferns and Equisetace^).

In the above cases the spores are always
formed in sporanges of various kinds, deve-
loped directly from the axis or the leaves
by a process of vegetative growth.

In the Mosses and Liverworts the spores
are mostly of one kind, consisting of a cell
with a single or (generally) double coat, like
a pollen-gi-ain. The spores, unlike those
above-mentioned, are formed in sporanges
which are the product of fertilized arche-
gonia, and more resemble the fruits of
Flowering plants. The spores of Mosses
germinate by emitting the inner coat as a
Ooufervoid filament (fig. 680), which usually
branches and gives
origin to numerous Fig. 680.

stem-buds. The
spores of the Liver-
worts exhibit many
modifications in the
first stages of ger-
mination, as illus-
trated by the ac-
companying figures Spores of a moss germinating,
(figs. 682-684) ; Magn. lOO diams.

the Marchantiee

and other frondose kinds grow at once into
thaUoid fronds (see Mosses and Hepa-
tic^).

The systematic position of the Characeie
is perhaps still an open question ; but there
can be little doubt of the analogies between
these red productive bodies and those of the
other Cryptogamia. There is no sporange
here, nor appare-ntly any archegonia. The
(/lobule (figs. 121 & 122, p. 162) produces
antheridia giving birth to spermatozoids.
The nucule (fig. 120, p. 161) appears to be
a spore (see Chaeace.3e).

In the Lichens, only one kind of organ
has been termed a spore, namely the repro-
ductive cells formed in the thec£B (PI. 37.
figs. 6 & 12), which are known to reproduce
the plant when thrown oft' by the parent.
Two other kinds of body connected with
the reproduction occur ; these, the tjonidia
(PI. 37. figs. 2, 3) and the spermatia (see
Lichens), have fortunately obtained and
preserved distinctive appellations. The
spores are simple cells or septate tubes,
with a double membrane.

In the Alg£e much confusion still exists,
not only between difterent lands of spore,
but even between spores and sporanges;
and this is not easily cleared away, since in
certain cases the organs appear really capable
of serving as one or the other, according
to circuinstauces ; the true spores are

SPOEES.

[ 725 ]

SPORES,

always simple cells with a double or triple
coat.

In the Floridefe, the characters of the
structures seem pretty clear ; we find spores
(p. 327), TETEASPonES (figs. 248-250),
which appear to represent the gouidia of
the Lichens, and spermatozoids (see Flori-
defe). Among the olive-coloured sea- weeds
(Fucoids), the Ffcace^e and Dictyotace j-
produce spores and spermatozoids ; but in
the majority of the families, only a totally
different mode of reproduction is known.
The plants produce ovate sacs, commonly
called spores, and chambered filaments ;
from both are discharged actively moving
ciliated cells, corresponding exactly to the
Zoospores of the Confervoids. Thm-et re-
gards the oosporanges and trichosporanges
(fig. 458, p. 501), as he called these sacs and
filaments respectively, as merely different
forms of one kind of structure. But it
seems possible that true spores may be dis-
covered, even indeed that the oosporanges
may be parent cells sometimes of zoospores
and sometimes of spores.

Fig. 682.

Fig. 683.

In the Confervoids we find true spores in
very many cases, pro-
duced generally after Fig. 681 .
some process of ferti-
lization or of Conju-
gation, in special
cells (fig. 668, and
PI. 9. figs. IG & 18 ;
PI. 10. tigs. 1-5). But
the " spores "' thus
produced, while they
sometimes germinate
into new filaments,
also sometimes pro-
duce numerous bodies
of different kinds,
connected in some
way with reproduc
tion ; this is the case
in Spirogyra (PI. 9.
fig. 23^, perhaps also in Closteeium and
other mstances. Besides the spores proper,
we have also in this family, Zoospores
— the actively moving ciliated bodies which
are regarded as gonidia and are fm-ther di-

Fig. 684.

Nodularia sjiuinigera.

Filaments with sporangial
cells containing quaternate
spores.

Magn. 200 diams.

Pellia epiphylla. Preissia commutata. Blasia pusilla.

Spores of Hepatic® germinating. Magnified 200 diameters.

vided into macrogonidia and microgonidia
(Hydeodictyon), the latter of which
may perhaps have the function of sperma-
tozoids (see Sph^roplea andVArcHERiA).
In the Fungi the greatest confusion exists
in.the nomenclature. The Agarics and their
congeners produce free naked cells at the tips

of short filaments, whence they ultimately
fall oft, to reproduce the plant ; these are
called spores or sporides, or distinctively
Basidiospores (figs. 53-55, p. 92). There
is no essential difference between them and
the spores produced by the Hyphomycetes,
either singly or in rows or capitula (Bo-

SPORES.

[ 726 ]

SPOROCmSMA.

TRYTis, figs. 77, 78, p. 116 ; figs. 685, 686;
and PI. 26. figs. 5, 6, 15, 16) at tlie ends of

Fig. 685. Fig. 686.

Fig. 687

Fig. 685. Mystrosporium Stemi^hylium, Corda (Stem-
phyhnm, Fries). Magn. 200 diams.

Fig. 686. Stachyobotrya atra. Fertile filament with
heads of acrogenous spores. Magn. 200 diams.

Fig. 687. A head of spores. Magn. 500 diams.

erect filaments ; these again appear to pass
almost insensibty into the conidia or repro-
ductive cells produced by tlie brealdng-up
of the mycelium, either wholly or in part,
into free cells capable of continuing the
growth (ToRULA, PI. 26. fig. 7, and Oidium,
fig. 8) : on the other hand, the spennatia
(figs. 2, .J, 4), such as occur in some of the
Coniomycetous forms of the Pyrenomycetous
and Discomycetous Fungi, are closely re-
lated, as far as structure goes, to the conidia
of Torula &c. and the spores of the Hy-
phomycetes; while the stylospores of the
Ukedhstei and Tremellini produce bodies
resembling them, and still more like the
basidiospores of the Agaricini. The stylo-
spores, another free form of spore, may be
regarded probably as compound organs,
fornied of a row of cells contained in a
persistent parent cell : it is sm-mised that
they are merely metamorphosed asci (see
Sph^rta and Stilbospora, PI. 26.
figs. 25-28) ; yet their mode of occurrence
woiild lead to the idea that they are a
distinct kind of organ. Lastly, we have
the ascospores or thecaspores (fig. 42, p. 78),
closely resembling those of the Lichens,
consisting of free cells with a double coat,
developed free in the cavity of a parent cell
or sac. In the British Flora the terms spo-
riile and sporidiimi are used synonymously
in the sense of spore, and are applied to
basidiospores, ascospores, stylospores, and
to the bodies (found in Cyiispora, Tuber-
cidaria, &c.) called by Tulasne spermatia.

The term sporidiola is applied apparently to
nuclei or granular masses occun'ing in the
cavities of spores, or to the separate portions
of contents of imperfectly septate stylo-
spores.

The sporangia of Diatomacese are some-
times called Auxospores.

With regard to the homologies of the
above structures, the spermatia are supposed
to represent spermatozoids ; the conidia are
regarded as corresponding to gonidia of
Lichens ; the stylospores are also connected
with these through the medium of the
tetraspores of the Floridese.

In conclusion, a reference may be made
to descriptions and figm-es like those given
(figs. 688, 689) oifree spores resting on the
matrix and among the filaments. Such
characters are totally out of date in the

Fig. 688.

Fig. 689.

Fig. 688. Leptotrichimi glaucum. Free spores among
the filaments of the matrix. Magn. 200 diameters.

Fig. 689. Fusarium herbariun. Free spores resting
on the matrix. Magn. 200 diameters.

present state of science, and simply serve
as indices of points requiring further in-
vestigation.

BiBL. See the heads of the classes of
Cryptogamic Plants.

SPORIDES'MIUM.— A genus of Toru-
lacei (Coniomycetous
Fungi), growing upon
bark, wood, &c. (PI.
27. fig. 12).

The character of
the spores seems to
vary in different spe-
cies ; sometimes they
are simply septate,
sometimes celliUar
(fig. 690).

See ToRiTLACEi.

SPOROCHIS'MA,

Sporidesmimn paradoxum.

Spores sessile on the
matrix.

Magn. 200 diams.

Berk, and Br. — A

SPOROCHNACE/E.

[ 727 ]

SPUMARIA.

genus of Torulacei ( Ooniomycetous Fungi),
contaiuiug one species, S. viirabih', forming
a black velyety stratum on rotten beech
wood. See Tohulacei.

SPOROCHNA'CE.E.— A family of Fu-
coidecie. Olive-coloured, inarticulate sea-
weeds, whose unilocular and septate spo-
ranges are attached to external jointed
filaments, which are either free or compacted
together into kuob-like or warty masses.

S)/nopsis of British Genera.

* Sporanges altached to pencilled Jihtments
issuing from the branches ( Arthrocla-
dieae).
Desmarestia. Frond solid or flat, di-
chotomously branched.

Arthrocladia. i^;-o»^7 traversed by a jointed
tube, filiform, nodose.

Stilophora. Frond filiform, tubular or
solid, branched ; sporanges arising from
necklace-shaped filaments collected in wart-
like groups upon the frond.

** Sporanges produced in knoh-Jike receptacles
coinposed of tchorled Jilameyits compacted
together (Sporochnese).

Sporochnus. Receptacles lateral, on short
peduncles.

Carpomitra. Receptacles terminal, at the
tips of the branches.

SPOROCH'NUS, Ag.— A genus of Spo-
rochnaceae (Fucoid Algas), containing one
British species, S. pedunculatus (PI. 4. tig. 1),
having a filiform, solid, cellular main axis
(containing a central cord of dense tissue),
bearing long slender branches arranged in a
somewhat pinnate manner and clothed at
intervals with elliptical fertile ramules, con-
sisting of an axis densely covered with whorl-
ed horizontal branching filaments bearing
ovoid sporanges, and terminating in a decid-
uous pencil of byssoid filaments. Main stem
6 to 8" long, olive-brown, changing to yel-
low-green on exposure.

BiBL. Harvey, Mar. Alg. 25, pi. 5 A ; Gre-
viUe, Alg. Br. pi. 6 ; Thuret, Ann. Sc. Nat.
3. xiv. 238.

SPOROC'YBE, Fries.— A genus of De-
matiei (Hyphomycetous Fungi), growing
on dead sticks, decaying stems, &c., forming
usually a blackish stratum. Several British
species are recorded. They have a rigid,
septate, simple or branched peduncle, endino'
with a capitate head clothed with spores
(figs. 691, 692). This genus is synony-
mous with Periconia, Corda. Periconia,
Tode, is an obscure form.

Ym. 691.

Fig. 692.

Sporocybe bulbosa.

Pig. 691. Stratum upon a stick. Nat. size.
Pig. 692. Two fertile peduncles, crowned with heads
of spores. Magnified 100 diameters.

BiBL. Berk. Br. Flor. ii. pt. 2. 3-33 ; Ann.
N. H. vi. 433, pi. 13 ; Fries, Sum. Veget.
467 ; Syst. My col. iii. 340.

SPOROT'RICHUM, Link.— A genus of
Mucedines (Hyphomycetous Fungi), grow-
ing on decaying vegetable substances, dung,
&c. The forms referable to this genus,
according to the character, include a very
heterogeneous assemblage ; indeed the cha-
racter which omits the nature of the original
attachment of the spores, is worth nothing.
Fries has separated a genus Trichospo-
BiUM, including a number of species with
distinctly acrogenous spores ; this includes
S. nigrum and ^S". geochroum of the Brit.
Flora. The remainder are placed by him
among the Sepedoniei, under Sporotnchum
and another genus which he calls Physo-
spora. These genera are very obscurely
known, much resembling mycelia with de-
tached conidia scattered on them.

BiBL. Berk. Br. Flor. ii. pt. 2. 346 ; Fries,
Sum. Veg. 492, 495, 521 ; Greville, Crypt.
Flor. pi. 108. figs, 1, 2.

SPUMA'RIA, Pers.— A genus of Myxo-
mycetes, the peridia of which are divided
internally into chambers by ascending folds,
and in S. alba are either sessile and pass above
into torn white laminae, or are stipitate and
divided, and form corniculate peridioles
bursting above ; the latter is probably the
perfect form. The whole plant looks at
first like white froth ; it groAvs on grasses
&c., generally at a little heiglit from the
ground.

BiBL, Berk. Br. Fl. ii. pt. 2. 309 ; Gre-
ville, Crypt. Fl. pi. 267; Sowerby, Fungi

SPUMELLA.

C 728 ]

STAINING.

(SeticuJaria), pi. 280; Fries, Sum. Veg,
449.

SPUMEL'LA, Cienk.— A genus of Fla-
gellate Infusoria. Minute, free or pedicied,
rounded or ovate, mouthless, with 1 long
and 2 short flagella. ^S". guUida and S. vivi-
para = Monas rj. and v., Elir. In pond water
and infusions. (Kent, Inf. 305.)

SPU'TUM.— We omitted to notice under
Expectoration the occurrence of fibrinous
casts of the smaller bronchi and pidmonary
air-cells in the expectoration of pneiimouia.
They are best seen on mixing the sputa with
water, forming dichotomous cylinders with
rounded enlargements. They consist of fine
filaments, and are mostly covered with gra-
nule-cells, and are generally met with be-
tween the third and the seventh day.

Koch's. Bacilhis tuberculosus of phthisis,
also deserves special attention.

BiBL. Remak, Diagn. ^c. TJntersuch.; Ed.
Mn, Jn. 1847, vii. 350 ; Gibbes, Lancet,
1882, ii. 183 & 797 ; Jn. 31. Soc. 1882, ii.
572

SPYRID'IA, Harv.— Agenusof Cerami-

Fig. 693.

Spyridia filamentoaa.
Fragment with a fayella and ramule8.
Magnified 25 diameters.

acese (Florideous Algse), containing one
British species, *S'. Jilamentosa (fig. 693),
having a dull-red, cylindrical, filiform,
much-branched frond, consisting of a cham-
bered tube, the articulations of which are
short, and the walls of which are composed
of small angular cells. It arises from a
hroadly expanded disk. The branches are
clothed with setaceous ramules. The
favellce are stalked, gelatinous, and lobed,
surrounded by a few ramules and contain
two or three masses of .spores. The tetra-
spores occur attached to the ramules. An-
ther idia have not yet been observed.

BiEL. Harvey, Mar. Alg. 166, pi. 22 D.

SQUAMA'RIA, DC— A genus of Placo-
dei (Lichenaceous Lichens) . Six species,
on calcareous rocks and earth. (Leighton,
Lich. Fl. 157.)

SQUAMEL'LA, Bory, Ehr.— A genus of
Rotatoria, of the family Euchlanidota.

Char. Eyes four, frontal ; foot forked ;
fi'eshwater.

S. ohlonga (PI. 44. fig. 29). Carapace
depressed, elliptical, or ovate-oblong, hya-
line; toes slender, long ; length 1-216".

S. hractea. Toes short and thick. (Ehr.
Inf. 479.)

■SQUAMULI'NA,Schultze.— An obscure,
small, parasitic, scale-like, opaque Forami-
nifer, probably Nubecularian.

BiBL. Schultze, Org. Polyth. 56; Car-
penter, For. 67.

STACHEI'A, Brady.— An adherent Are-
naceous Foraminifer, with numerous subdi-
vided chambers, acervuline or in irregular
layers. Six fossil species (Carboniferous).
(Bradv, Carhonif. Foram., Pal. Soc, 1876,
107.) ■

STACHYLIDTUM, Link.— A genus of
Mucedines (Hyphomycetous Fungi), nearly
related to Botrytis, distinguished apparently
only by the subpedicellate spores. Fries
states that these are developed within a
fugacious veil (?). Botryosporium dif-
fusum, Corda, is included here by most
authors. S. hicolor and ^S". terrestre, having
quaternate sporiferous branches at the upper
joints of the erect, simple filaments, grow
upon decaying herbaceous plants and rotten

StlOKS

BiBi.. Berk. Br. Fl. ii. pt. 2. 341 : Fries,
Su7n. Veg. 490; Greville, Crgpt. Flor. pi.
257

STAINING. — The staining or dyeing
process was introduced by Gerlacb, after
observing in his carmine injections, how
differently the elements of the tissues were
dyed by the colouring-matter.

The general action of the dye is, that the
nuclei and the protoplasm of the cells are
deeply coloured, while the cell-walls are
but little acted upon, and the intercellular
substance is hardly at all affected. The
cause of this difference in the dyeing effect
lies partly in the physical and partly in the
chemical condition of the organic matter.

If the dye-liquor be too strong, or its
action too long continued, the whole tissue
will become confusedly coloured, and its
elements undistinguishable.

The dyes which have been used are very

STAINING.

[ 729 ]

STAINING.

give a sketch of the

numerous ; we will
priucipal and their uses.

Among- these are carmine, indigo-carmine,
alkaUne sulphindigotates, saiiron, aniline
blue, eosiue, I'uchsiuo, magenta, logwood,
picric acid, ink, and Judson's dyes.

Frey recommends that 3 to 0 grains of
carmine (better carminic acid ?) be dissolved
in a few drops of Liq. Ammon., with an
ounce of distilled water. To the filtered
liquid is added 1 ounce of glycerine, and
2 to 3 drachms of alcohol. This solution
may be used alone, diluted with water, or
with glycerine. The duration of the mace-
ration will vary according to the kind of
tissue and the strength of the dye-liquor ;
in some cases a few minutes are enough, in
others 24 hours are required. The pieces
of tissue are then washed with water or a
very weak acid (an oimce of distilled water
with 2 or 8 drops of acetic acid). Fresh
tissues, or those hardened by alcohol are
best ; next those previously treated with
chromic acid or bichromate of potash.
Preparations to be preserved in feebly acidi-
fied glycerine require to be less dyed than
those to be moimted in balsam.

Gerlach used a concentrated solution of
carmine in ammonia, and placed the sec-
tions of brain and spinal cord, previously
hardened by solution of chromic acid, in the
carmine solution for ten or fifteen minutes.
They were then well washed in water and
treated with acetic acid ; subsequently the
water and acid were removed by absolute
alcohol ; and the preparations were then
mounted in Canada balsam. Afterwards
he found that better results were obtained
by using dilute solution of carmine and
ammonia — for instance, two or three drops
of the ammoniacal solution to an ounce of
water. He advised also maceration in this
solution for two or three days. Beale's
carmine fluid for staining protoplasm is
made as follows : —

Carmine 10 grains.

Strong liquor ammonite h drachm .

Price's glycerine 2 oimces.

Distilled water 2 ounces.

Alcohol I ounce.

The carmine in small fragments is to be
placed in a test-tube and the ammonia
added to it. By agitation and heat the car-
mine is soon dissolved ; "then the solution is
boiled for a few minutes and allowed to cool.
After an hour any excess of ammonia will
■ have escaped ; the glycerine and water
may then be added and the whole filtered.

The clear fluid is to be kept in stoppered
bottles ; and should any carmine be preci-
pitated, a drop or two of liquor ammonife
should be added. Care should be taken
that the solution and the tissue to be stained
have not too alkaline a reaction; other-
wise the staining Avill be too intense, and
some of the tissue surrounding the proto-
plasm will be destroyed. The permeating
power of the fluid is increased by the addi-
tion of alcohol and water. This is a most
valuable staining agent, but requires care.
Thiersch recommends: — carmine 1 part,
caustic ammonia sol. 1 part, distilled water
3 parts ; the solution is to be filtered ; oxalic
acid 1 part, distilled water 22 parts. One
part of the carmine solution is to be mixed
with 8 parts of the oxalic acid solution, and
12 parts of absolute alcohol are to be added.
Should the solution turn out orange-co-
loured, more ammonia should be added.

A solution of carmine in borax is some-
times used — 4 parts of borax dissolved in
50 parts of water, to which is added 1 part
of carmine. The filtered solution is mixed
with 2 volumes of alcohol. This solution
answers well in dyeing cartilage.

Frey gives the following formula for
Thiersch's blue staining fluid : — Oxalic acid
1 part, distilled water 22 parts, indigo-car-
mine as much as the solution wiU take up.
Another solution of oxalic acid and water
in the same proportion is required; and one
volume of the first solution is mixed with
two volumes of the last and nine of absolute
alcohol. An aniline-blue solution may be
made as follows : — Soluble aniline blue
I grain, distilled water 1 oz., alcohol 2odrops.
This fluid is not acted on by acids or alkalies.
Magenta colours rapidly, and hence it is very
useful ; but its eftects are not permanent.
Eutherford gives the following formulae : —
Crystallized magenta 1 grain, absolute alco-
hol 100 minims, distilled water 5 oz. This
is used for the tissues generally; and the
following is for blood-corpuscles : — Crystal-
lized magenta 1 part, rectified spirit 50
parts, distilled water 150 parts, glycerine
200 parts.

Very often nerve does not stain readily
with carmine after hardenino- in a solution
of chromic acid. This maj^ be obviated bv
placing the section in absolute alcohol for a
short time in order to get rid of the water ;
then it is placed in a solution composed of
water 300 to 600 parts, and chloride of pal-
ladium 1 part. As soon as a pale straw-
colour is seen on the section, it may be

STAmrxG.

[ 730 ]

STAMENS.

removed from the solution and washed, and
then placed in a strong solution of carmine
and ammonia. A very few minutes will
suffice to stain the axis-cylinders red and
the medullary matter yeUow {Qii. Mic. Jn.
1872, 160).

A blue staining agent, useful for treating
specimens of the spinal cord, is formed by
the reaction of molybdate of ammonia, iron
filings, and hydrochloric acid {Qu. Mic. Jn.
1872, 161).

A logwood staining solution, which con-
sists of an ounce of satm-ated solution of
logwood and alum mixed with two di'achms
of 75 per cent, alcohol, is useful for the
nervous elements {Qu. Mic, Jn. 1873, 87,
& The Lens, Jidy 1872).

Other staining agents comprise especially
the chlorides of gold, potassium and palla-
dium, oxide of uranium, nitrate of sOver,
and osmic acid. In these, except perhaps
in the last, a secondary decomposition
occm-s before the colour is imparted to the
tissues ; and the greatest possible care must
therefore be taken to allow for the gxanular
or striated condition which such precipitates
may assume, and for their collecting in
tubes and between tissues. An excellent
f ornuda for staining ganglion-ceUs especially
is as follows: — Bichromate of ammonia
1 to 2 per cent, solution in water. Place
the fresh nerve-substance in it for 15 or 20
days. Then dip it, after having made sec-
tions, in water 10,000 parts, double chlo-
ride of gold and potassium 1 part : wash in
hydrochloric acid 1 or 2 parts in 3000 water.
Then dip for ten minutes in the following
mixtiue : — Hydi'ochloric acid 1 part, and
1000 parts of a 60 per cent, solution of
alcohol ; immerse in absolute alcohol, clear
^vith oil of cloves, and put up in Canada or
Dammar balsam. Staining with chloride
of gold may be conducted as follows, the
object being to stain nerve-fibres : — Chlo-
ride of gold ^ part, distilled water 100 parts.
Place pieces of fresh tissue in this for a few
minutes until they become tinged with
yellow, then in dilute acetic acid (1 to 2 per
cent.), or in concentrated tartaric acid solu-
tion for a few (10-15) minutes. Expose to
light until a violet colour appears. Mount
in glycerine. There is great uncertainty in
the results of this process ; but care and
experience overcome most of the difficulties
and produce magnificent preparations ;
ue^'ertheless no results are worth recording
which are obtainable by this process alone,
and which are not the same as those vi-sible

with glycerine and carmine staining solu-
tions. The discrepancies of observation of
different and equally dogmatic observers are
most instructive. In fact in some tissues
the gold solution will stain many histolo-
gical elements (see Klein, Qu. Mic. Jn.
1872, 21 ; and Moseley, Qu. Mic. Jn. 1871,
68). _

Nitrate of silver for staining epithelial
cement in capillaries, lymphatics, &c. The
solution must be clear and weak, and of
1 part nitrate of silver to 200, 400, or 800
of distilled water. The fresh tissues must
be macerated in the solution for one to
three minutes, and then in a solution of
dilate acetic acid (1 to 2 per cent.) for a
minute or two. Then place in glycerine
and expose to the light ; or after removal
from the nitrate-of-silver solution the tissue
shoidd be washed in distilled water, or in
a weak solution of common salt before ex-
posure to light.

In examining the tendinous centre of the
diaphragm of any of the smaller mammalia,
the part should be placed in the nitrate-of-
silver solution and brushed over with a
camel's hair pencil and then removed and
treated as above.

Solution of osmic acid may be used as a
hardening agent, also as a staining medium.
Solution of 1 per cent., and usually of much
less, blackens many tissues freely, especially
the white substance of Schwann in nerves,
and fat. It is very useful in investigating
the minute anatomy- of the Invertebrata.

Many parts of animal tissues may be
stained by maceration in a weak solution of
acetate of lead, washing in water, and
digesting with weak hydrosulphuret of am-
monia. As usual, the nuclei are rendered
very black and distinct, the whole tissue
being rendered brown.

Vegetable tissues may be stained in the
same way as the animal structures. The
aniline dyes answer best (Beatty, Mn. Mic,
Jn. xiv. 57).

BiBL. Beale, How ^c. ; Strieker's Hist.,
Intro. ; Frev, Mikros. ; Rutherford, Hist. ;
Jackson, Qu. Mic. Jn. 1874, 139; Ehrlicli,
Schultz&s Archiv, 1873, xiii. 263; Gibbs,
Hist.; Tafani, Jn. M. Soc. 1878, i. 82;
Merbel, M71. Mic. Jn. xviii. 242 ; Sternberg,
Jn. M. Se. 1882, ii. 571 (staining Bacteria) ;
Schwartz, Sitz. Be): Wien. Ak. 1867, Iv.
071.

STAMENS.— The fertilizing organs pro-
ducing the POLLEN, surrounding the pistil
in perfect Flowering plants, or occurring

STARCH.

[ 731 ]

STARCH.

alone in the barren flovcers of the monoe-
cious and dicvcious genera. Stamens pre-
sent a great variety of interesting points for
examination under a simple microscope
with a knv power, in their forms, append-
ages, pores, itc. For the compound micro-
scope they aftbrd good material for the study
of development of cells in the pollen, the
POLLEN-grains themselves, and the spiral-
fibrous tissue of their anthers.

STARCH or Amylfm. — This substance,
with the exception of the protoplasm, is the
most generally diffltsed of all the products
met with in the interior of vegetable cells,
and occurs in the form of transparent gra-
nules, of varied size and form and in varymg
quantity, in all classes of plants but the
Fungi. It has been stated that it sometimes
exists in a diffused or formless condition ;
but this seems questionable. All starch-
gi'ains appear when newly formed as mi-
nute spherical bodies, and very many never
advance beyond this stage ; but a consider-
able proportion of the grains, in all cases
where the starch becomes an important and
considerable element in the cell-contents,
increase in size, and acqmre a more or less
definite form, diverging from the spherical,
and often characteristic of the particular
plant in which the gi'ain is pi'oduced. The
grains in a single cell mostly vary very
much in size, on account of their different
degrees of development ; but the full-grown
characteristic grains of the same species of
plant agree tolerably well in size. One of
the most remarkable peculiarities of starch
is the fact that it assumes a blue colour
when iodine is applied to it, which in most
cases affords a ready means of detecting its
presence. The smallest grains are almost
too minute to measure, and even their de-
termination by the application of iodine is
sometimes unsatisfactory ; the largest grains,
such as those of Carina and the potato, for
example, attain a length of more than
1-400".

The starch-granule is a definitely organ-
ized structure, although its existence in
relation to that of the cell is ti'ansitory. It
consists of assimilated food, deposited in a
definite form insoluble in the ordinary cell-
sap, through a process of organization ana-
logous to that by which the development of
the cell itself is effected. It is related
closely to the ceUuhjse structures of the cell-
wall through the remarkable secondary
layers foimd in the Axbi^men of certain
seeds, composed of the substance called

served, more
cases, which

ann/l<nd, which sometimes takes a blue
colour when iodine is applied to it, and,
like starch, is ultimately dissolved and re-
moved to furnish material for de\olopmeut.

The structure of the starch-granule has
formed the subject of much debate, wliicli,
however, seems to have originated rather
through considerations relating to the deve-
lopment than from a difficulty in observing
the complete objects. Very minute granules,
as above stated, appear as solid globules ;
but when the granules acquire appreciable
dimensions, concentric lines may be ob-
or less distinctly in difterent
lines increase in number with
the increase of size, in many cases, however,
soon becoming exceutrical from the pre-
ponderating growth of one side of the
granule. In freshly extracted granules the
original centre usually appears solid or with
a minute black point ; but if the starch is
dry, the centre appears hollow, sometimes
is even occupied by air ; and some starch-
grains, as in Irispallida,Jioyentina, &c., have
a large cavity. If strong alcohol is applied
to fresh grains, the abstraction of water
likewise produces a hollow in the central
point of growth ; and in all these cases,
cracks not unfrequently run out towards
the surface. The point in question, the
starting-point of growth, solid or hollow as
the case may be, is sometimes called the
hihtm or the rincleus : the former term arose
out of the mistaken hypothesis of its being
a point of attachment to the cell- wall ; the
latter term is admissible in a general sense
as merely indicative of its precedence in age
of the general mass of the grain. It is
sometimes asserted that this point or nucleus
is a pore or fimnel-shaped cavity ; but this
is altogether a mistake, as may be readily
proved by gently roasting a few starch-
granules of the potato on a slide, and ob-
serving how the expanding air blows up
the dextrine, into which the starch is
changed, in the form of a bubble or bladder.
Sometimes small granules occur in the
potato with a large cavity and thin walls.

The lines seen in the starch -granules are
the boundaries of superimposed layers of its
substance ; sometimes these are very di-
stinct, sometimes very faint. Often more
distinct lines appear at intervals in the
series of the same gi'anule (PI. 40. fig. 31) ;
and in these cases even a thin vacancy, or
in the dried granules a stratum of air, seems
to exist between the layers. The markings
have been described as " folds " on the

STARCH.

[ 732 ]

STARCH.

starch-pranules ; but their dependence on
the existence of the concentric layers is
beyond doubt. They are seen in the proper
relative positions when the g-ranides are
rolled over in all directions beneath the
microscope ; their relative numbers and
forms correspond to the size and stage of
development of the granules in the same
plant ; and other characters connected with
the physical structure confirm the conclu-
sions from simple inspection.

Starch is not chemically an individual
substance, but consists of two independent
isomeric substances : one of which, granu-
lose, is soluble in saliva, is coloured blue by
iodine, and is dissolved by weak solutions of
chromic acid ; while the other, cellulose,
which composes from 2 to 4 p. c. only of the
grains, is not affected by saliva or iodine, and
is soluble in solution of cuprate of ammonia,
but not in chromic acid solution.

Starch is usually stated to be miaffected
by cold icater, and this is generally the case ;
but if the granides of Tous-les-mois are
crushed before placing them in water, so as
to expose the internal substance, the water
is sometimes absorbed by the inner layers,
and these swell up considerably without the
outer layers being affected. When dry
stare li-granules are heated gradually upon a
slide, until some of them assume a yellowish
colour, either the air-bubble above-men-
tioned appears — occasionally with a partial
separation of the concentric layers through
expansion of the films of air existing between
them, while other parts become fused, — or
the general shape remains unchanged, and
the strife gradually vanish, becoming melted
into a mass, as it were, the starch itself
being converted into dextrine. When
starch-granides are heated in water to the
boiling-point, they usually soften and
" blow up " into a large sac, the inner part
softening first, and pushing out the more
superficial ; if the sac bursts, the inner siib-
stance sometimes partly escapes in the form
of cloudy fiocks, but is not dissolved. Di-
luted sulphuric acid acts somewhat in the
same manner as hot water ; but if stronger
acid is allowed to attack the granules locally
or partially by flowing in from one side
upon the object, very remarkable appear-
ances present themselves : the acid touching
certain parts of the granule first, or acting
most quickly on softer portions, causes the
softening internal layers to expand and
bulge out tlie external layers at particular
points (like hemice) until the entire gi-ain is

softened, when these coalesce and the whole
expands into a thin sac. Gradual action of
the acid causes a more uniform expansion,
which is usually accompanied by a sudden
crack running out from the nucleus into the
substance (indicating the abstraction of
water ?), followed almost immediately by a
collapse of the wall above this crack, and
a sudden expansion of the whole into a sac
or an irregular gelatinous film. Solution of
potash produces much the same effect as
dilute sidphuiic acid.

All the above appearances indicate that
the starch-granule is composed of concentric
" shells " of a substance of the same nature,
but less dense and more rich in water in the
interior layers, firmer, less hydrated, and
more resisting in proportion to the distance
from the starting-point of growth or nu-
cleus ; and, according to modern views, the
layers are alternately more and less hydrated.
With polarized light, moreover, the starch-
granule exhibits a black cross, and with a
plate of selenite a beautiful coloured system,
especially well seen in large grains like those
of the potato or Tous-les-mois.

Pure starch is coloured blue by iodine,
whether in its natiu'al state or softened by
hot water, the depth of the colour depend-
ing on the quantity of iodine ; where much
is added, the colour is almost black. When
dilute sulphuric acid has been added pre-
viously, the coloiu' is rather purple than
blue, especially the faint tinge given at first
by weak solution of iodine. When the
starch grains are heated di-y, the colour
given by iodine changes, proportionately to
the violence of the action, from blue to
purple, red-wine colour, and finally brown ;
the starch being converted into dextrine.
The best application is the solution of iodine
in iodide of potassium ; and this should be
used very weak in investigation of starch.

Starch-granules occur either isolated (PI.
46. figs. 8 & 21), or in groups (figs. 7, 10, 11)
(in the latter case mostly with fiat faces, so
as to fit together into round, oval, or similar
forms), or packed closely in the parent cell
in such numbers that they press upon each
other and appear like parenchymatous cells
(PI. 46. figs. 3 & 12). In the actively vege-
tating parts of plants, starch-granules occur
A'ery generally imbedded in the green glo-
bules called CHLOROPHVi.L-graiuiles, either
singly or in groups ; this is seen especially
well in the cells of the Confervacepe, of the
Hepaticse, the prothallia of Ferns, in the
leaves of aquatic plants, such as Vallisneria,

STxSJlCH.

[ 733 ]

STARCH.

in autumn, &c. The free granules occur
more particularly in the colourless oi'gans
of plants — ill tubers, rhizomes, roots, and the
cambium region in the season of rest, in
the endosperm of ovules, or the albumex or
cotyledons of seeds, &c. The parenchyma-
tously grouped granules are tound in the
albmnen of seeds, especially of maize and
rice. The compaiison of the istates and of
the course of development of the crowded
granules of maize throws much light upon
the manner in which starch-granules are
formed.

In the first place, two rival doctrines exist
as to the order of development of the parts
of the granule. Most authors assert that
the granules grow by the superposition of
layers from within outwards, consequently
that the outermost layers are the youngest.
Other authors, especially Niigeli, comparing
the granule to a cell, assert that the layers
are formed internally, the older ones ex-
panding to make room for them. There
can be no doubt that the first view is cor-
rect. In the next place a variety of notions
have been put forth as to the origin of the
starch-granule and its relation to the rest
of the contents of the cell, especially the
chlorophyll. It is curious to note the error
into which earlier observers fell from the
want of the guiding thread liu'uished by a
knowledge of the function of the proto-
plastic structures connected with the pri-
mordial utricle. The idea that the starch-
gi'anule sprouted out from the cell-wall
coiresponded with the original view of the
origin of the septum in cell-division ; while
the hypothesis that starch is developed from
chlorophyll, and the contraiy notion that
starch-granules form the nuclei of chloro-
phyll-granules, both rest on actual pheno-
mena, in which, however, the chlorophyll
proper, that is the mere green colouring-
matter, bears no important share.

The development of the starch-granule is
very beautifully illustrated in the gradual
ripening of the seeds of Maize ; and in im-
perfect seeds, difl'erent parts of the same
gi'aiu often exhibit various stages of growth.
The figs. 1 and 3 of PI. 46, show the gi-adual
formation of the starch-gi-anules by depo-
sition from the internal smface of vacuoles
in the protoplasm filling the cell, exactly in
the same way as the primordial utricle
secretes cellulose layers upon its outer sur-
face. Fig. 28 shows minute starch-granules
originating in the same way in the proto-
plasm-current connected with the nucleus

in the white lily ; and Criiger, who first
published this view in a decided form, has
shown that the large granules, with an ex-
centric hilum, originate in a similar position,
and owe the excentricity of their form to
the fact of their remaining imbedded at the
thicker end in the protoplasmic threads of
the primordial utricle, while the small free
end is gradually pushed out fm-ther from
the nutrient mass. The existence of starch-
grauides in chlorophyll-masses is thus clearly
enough accounted for, now that we know
the chlorophyll-globules to consist of masses
of protoplasm coloured green by the presence
of an extremely small quantity of a sub-
stance acquiring a green colour under the
influence of light. Starch originates in
vacuoles in this as in any other protoplasm.
The gi-oujys of granules are formed through
the simultaneous origin of a number, in
vacuoles excavated in one large globule of
chlorophyll or colourless protoplasm. We
have traced this in the fronds of the Hepaticse.
It remains to speak of the diversities of
form and size of the large and perfect gra-
nules in difl'erent plants. A glance at
Plate 46 will give some idea of these, and
an inspection of the individual figures will
show how remarkably the characteristic
forms may vary in nearly related plants,
even genera of the same family, as is the
case with the ordinary Cereal grains. Thus
in Maize (figs. 1,3,5), where the small grains
are, as usual, originally roundish or oval
(fig. 5*), they gradually press upon one an-
other and become polygonal — in the cells of
the centre of the grain, where they are less
densely packed, lemaining wdth obtuse edges
and angles (fig. 5), in the cells of the homy
outer part of the grain, where they adhere
more or less firmly together, forming an-
gular parenchymatous masses (%. 3). The
central cavity is large here. In the grain
of Wheat we find delicate, transparent, len-
ticular granules (fig. 8), the strias faint ; in
Barley (fig. 9) they are more irregidarly
discoid, with a thickened edge, the striae
obscure ; while in the Oat (fig. 10) the
granules are ofvery small size, but of angidar
forms and packed together in large numbers,
so as to form roundish masses with a smooth
surface, w'hich readily break down into their
components when pressed ; the separate seg-
ments all exhibit their separate black crosses
in polarized light. In Rice (fig. 12) we find
somewhat similar conditions to those in
Maize ; but the granules are much smaUer
and more firmly united, whence the gritty

STAURASTEUM.

[ 734 ]

STAUROCAEPUS.

character of rice-flour. In the Leguminosse,
and the pea (fig. Q b*, p. 28), the gi-auules
are oblong, the striae distinct, and the hilum
radiate. In the Potato the starch-granides
(fig. 21) are larger than any of the above ;
they are numerous and closely packed in the
cells (fig. 20) . Among the more remarkable
forms of starch are the large grains of the
CamwB (fig.25), J/"«sa(fig.24),and most of the
Zingiberaceae (fig. 19). Some East-Indian
Arrow-root (fig. 18) has compoimd grains
of large size (mostly detached in the pre-
pared farina). True West-Indian Arrow-
root, from Maranta arundinacea, is repre-
sented in fig. 26. Various other kinds are
illustrated in PI. 46. Dieffenhachia Seguina
(Araceae) has remarkable lobed granules.

Here maybe mentioned the so-called taimiu
starch-grains. These resemble ordinary
stai-ch-grains, but the cellulose is replaced
by tannin, the granulose being unaltered ;
they are coloured blue-black by iron solution,
and are found in wood, seeds, &c.

Starch-granules are usually isolated by
slicing the tissues in which they exist, and
washing them out. When they are to be
observed in situ, either delicate transparent
structures (as in the Cryptogamia) must be
selected, or sections very carefidly made.
The cells filled with starch of the potato
(PI. 46. fig. 20), &c., may be isolated by ma-
cerating the structures in water for a day or
two. Starch-granules may be preserved for
a certain time in glycerine ; but they are,
perhaps, best taken fresh from a store of
dry granules, when required for examination.

BiBL. Martin, Phil. May. iii. 277 ; Busk,
Mic. Tr. i. 58 ; Allman, Mic. Jn. ii. 163 ;
Criiger, Bot. Zeit. xii. 41, Mic. Jn. ii. 173 ;
E. Quekett, Ann. N. H. xvii. 193 ; Caspary,
Jahrh. iviss. Botanik, i. 448 ; Trecul, Ann.
Sc. Nat. 4. X. ; Niigeli, StarkeJcd)-ner ^-c. ; and
Sitzunc/sber. bayer. Ak. 1865 ; Sachs, Bot.
58 ; Henfrey-Masters, Bot.

STAURAS'TRUM, Meyen.— A genus of
Desniidiacese.

Char. Cells single, constricted at the
middle ; end view angular or circular, with
a lobato -radiate margin, or rarely com-
pressed with a proct'ss at each end. Spo-
rangia generally spinous and often globose.

Many British species.

S. ili'jevtum (PI. 14. fig. 26). Segments
smooth, lunate or elliptical, constricted por-
tion very short ; end view with inflated
awned lobes. Common ; length 1-830".

S. maryavitaceum (PI, 14. figs. 28, 29).
Segments rough, tapering at the constric-

tion, and with short lateral processes ; end
view with five or more short, narrow, ob-
tuse rays. Length 1-1176".

S. yracile (PI. 14. fig. 30). Segments
rough, elongated on each side into a slender
process terminated by minute spines ; end
view biradiate. Length 1-770 to 1-540".

BrBL. Ralfs, Desmid. 119 ; Rabenht. Aly.
iii. 109; Archer and Dixon, Qu. Mic. Jn.
viii. 77 ; ib. xvii. 103.

STAURIDIUM, Duj.— A genus of
Hydroid Zoophytes.

Char. Stems simple or branched, rooted
by a creeping filiform stolon ; polypes
borne at the summit of the stems with
several whorls of capitate tentaciUa in the
form of a cross.

S.productum. On marine algje. (Hincks,
Hyd. Zooph. 67.)

STAUROCAR'PUS, Hassall {Stauro-
spe7-mum, Kiitz.). — A genus'of Zygnemacese
(Confervoid Algae), growing in boggy
freshwater pools ; distinguished by the re-
markable quadrate spore formed in the
cross branch produced by conjugation.
Ilassall enumerates six species. He speaks
of, but does not describe or figure, the spores
of S. ccerulescens as filled with zoospores.
Thwaites, however, saw the spores of S.
yracilis resolved into four portions ; and pos-
sibly these may become converted into
zoospores like the spores of Bulbocil/ETE ;
or probably they ger-
minate directly, as in ^^&- "''*•

Spiroyyra.

S. yracillimus. Fila-
ments 1-4200" to
1-3960" in diam. ;
spores acutely qua-
drangidar.

S.f/racilis (fig. 694,
and" PI. 9. fig. 16).
Filaments thicker
than in the last ;

spores cruciform. Stam-ocarpus gracilis.

iS. ylutinosilS. Fila- Conjugating ttlaiueuts with
ments 1-1 SOO" to ^poi-es (zygosiiores).

] -1560" in diam. ; blu- Maguidert m diu.ueters.
ish green, lubricous ; spores four-sided, with
the angles rounded.

8. cfcrulescens. Filaments about the same
size as the last ; spores cruciate, with obtuse
lobes.

»S'. quadratus. Filaments 1-2400" in diam. ;
spores between square and globose.

S. virescens. Filaments 1-3240 to 1-3000"
in diam. ; spores cruciate, emarginate.

BiBL. Ilassall, Alff. 176 J Kiitziug, Sp.

STAUROGENIA.

[ 735 ]

STENOGRAMME.

Phyc.

& 9;

V. pis. 8
N. H. x\-ii. 262; Ralfs,'
Brauu, J^erjiinc/ung, Bay

-A genus of

arrauged in

Alg. 437 J Tab
Thwaites, Ann.
Desmid. p. 146 ;

Soc. 1853, 287.

STAUKOGE'NIA, Kutz.-
Unicelliilar Algre.

Char. Cubical, the cells
gi'oups of 4, 8, and 16. Propagation by tran
quil gonidia arising from repeated division
of the cell-substance. -S'. quadratum (PI. 52.
fig. 21). In freshwater pools.

BiBL. Rabenli. Alq. 'in. 80.

STAURONEIS, Ehr.— A genus of Dia-
tomacese; including Staiirostiyma and Stau-
roptera.

Char. Frustules resembling those of iVa-
vicida, but the median nodule expanded
into a transverse band or stauros.

Striae resembling those of Naoicula, or
intermediate between thosQ oi Navictda and
Pinnularia ; often invisible by ordinary
illumination.

The species or forms are numerous.

S. phoenicentci-on (PI. 15. fig. 43. Valves
lanceolate, gradually attenuated towards
the somewhat obtuse ends ; stam'os reaching
the margins of the valves; strife faint.
Freshwater; common; length 1-170"

S.pidchella (PI. 15. figs. 44,45). Valves
oblong, ends obtuse; frustules in front
view broadly linear, constricted in the
middle, and rounded-truncate at the ends ;
sti'iaj distinct ; stauros not reaching the
margins. Marine; length 1-70".

BiBL. Ehrenb. Ber. Berl. Ak. 1843;
Kiitz. Bacill. 104, and Spec. Alg. 89 ; Ra-
benh. Alg. i. 244.

STAUROSPER'MUM,Kiitz.=.STArao-
CAEPus, Hassall.

STEARIC ACID.— The crystals of this
fatty acid are represented in PL 11. fig. 16.

STEGANOPOREL'LA,Smitt.— A genus
of Polyzoa = Membi^anipora pt. (Hincks,
Polyzoa, 176.)

STEMONI'TIS, Gled.— A genus of
Myxomycetes, consisting of little, somewhat
stamen-shaped plants, either separate or

fascicidated,

on rotten wood, &c.

They appear at first in the form of a muci-
laginous fiocculent expansion (fig. 695), from
which the membranaceous peridia grow up
(fig. 696). Many of these remain abortive ;
others are raised upon stalks, ripen, and, on
the separation of the fugacious peridium,
display themselves somewhat in the form
of Di ACH.s;A,but with a bristle-like columella
and no remains of the peridium. The flat,
cylindi'ical or globose, reticulated capilli-

Fig. 695.

Stemonitis ferruginea.
Mycelium overgrowing decaying pine-leaves.

Fig. 696.

stemonitis ferruginea.

Immature (fasciculate) peridia arising from the

mycelium.

tium is penetrated partly or through its
whole length by a columella continuous
with the peduncle ; the spores are inter-
spersedin the reticulations of the capiUitium.
Capillitium and spores mostly of blackish
colour. There are numerous British species ;
S. fiisca is common. See Enerthenema
and DiACH^A.

BiBL. Berk. Br. Fl. ii. pt. 2. 317 ; Ann.
N. H. i. 257, vi. 431, 2. v. 366 ; Greville,
Cnjpt. Flor. pi. 170; Fries, Sum. Veg. 455;
Syst. Myc. iii, 156.

STENHE'LIA, Boeck.— A genus of Co-
pepodous Entomostraca. Two species, on
Laminaria and in dredgings. (Brady, Copep.
ii. 32.)

_ STENOO'YBE, Nyl.-A genus of para-
sitic Micro-lichens fumid on the thallus of
Thelotrenia and Graphis = Sphinctrina,
Leightou. (Lindsay, Q. Mic. Jn. 1869, 146.)

STENOGRAM'ME, Ilarv.— A genus of
Rliodymeniacese (Florideous Algse), con-
taining one very rare British plant, S. in-
terrupta, characterized by stalked, flat, fan-
shaped fronds, more or less divided dicho-
tomously into riband-like lobes, 3-5" high,
of a clear pinky-red coloiu'. It is com-
posed of a centi'al laj^er of large globular
cells, with a kind of rind of small cells.
The conceptacles form a sort of sorus or dark

STENTOR.

[ 736 ] STEPHANOSPH^RA.

line resembling a rib, up tbe centre of each
fertile lobe. Tetraspores and antheridia
unknown.

BiBL. Harvej', Marine Alg. 123, pi. 15 D.

STENTOR, Oken.— A genus of Hetero-
trichous Infusoria, of the family Bursarina.

Char. Body conical or trumpet-shaped,
fi'ee, or sessUe and attached by the narrow
base, covered with cilia; anterior portion
widened and fringed with a marginal row
of longer cilia, with a spiral row of ciha
extending from it to the mouth. Fresh-
water.

These Infusoria are among the largest
and the most beautiful of the class. The
body is very contractile and liable to varia-
tion in form, often becoming ovate, oblong,
or globular; the nucleus is moniliform or
strap-shaped. Reproduction by oblique fis-
sion, and by germs arising from the nucleus.
The enc^'sting process has been noticed in
some of the species.

According to Lachmann, in S. Miilleri,
jjoli/morphus, and Rwselii, near the plane of
the ciliary disk is a large contractile vesicle,
from which a longitudinal vessel with
several dilatations runs to the posterior ex-
tremity of the body"; also an annular vessel
round the cUiary disk, close under its row
of cilia.

S. Miilleri (PL 32. fig. 3). Body colour-
less imless from containing foreign coloured
particles, with a fringe of cilia or a ciliated
crest extending from the mouth to near the
middle of the body ; nucleus monUiform.
Length 1-24"

Several other species.

Dajardin places this genus in the family
Urceolarina.

BiBL. Ehr. Inf. 261 ; Stein, Infus.., pas-
sim ; Pritchard, Inf. 581 ; Clap, et Lach.
Inf. 222 ; Kent, Inf. 588 ; Laukester, Qu.
M. J. 1873 (col. matter).

STEPHANOC'EROS, Ehr.— A genus of
Rotatoria, of the family Floscularifea.

Char. Eyes single ; rotatory organ di\aded
into five tentacle-like lobes, furnished with
whorls of vibratile cilia ; body attached
by the base to a cyhudrical hyaline ca-
rapace.

*S'. Eichhornii (PI. 44. fig. 25). The only
species. Freshwater; length 1-36". This
beautiful animal uses the lobes of the ro-
tating organ to catch its prey, in the manner
of Hydra. At a (tig. 25) are seen the tre-
mulous bodies, above Avhich is a row of
roundish globules, called by Ehrenberg ner-
vous ganglia.

BiBL. Ehr. Inf. 400; Pritchard, Inf.
668 ; Oubitt, Mn. Mic. Jn. iii. 240.

STEPHANODIS'CUS, Ehr.— A genus
of Diatomacefe.

Char. Frustules discoidal, single ; valves
circular, alike, not areolar (under ordinary
illumination), and with a fringe of minute
marginal teeth ; freshwater.

»S'. berolinensis has the valves finely ra-
diate, with mostly thirty-two teeth, and is
1-1 LoO" in diameter. S. Niagarce (PL 18.
fig. 26) ; »S'. lineatus (fig. 27) ; S. sinensis
(fig. 28) ; S. Mgijptiacus (fig. 29) ; S. Bra-
maputrcB (fig. 29*).

Blbl. Ehrenb. Ber. Berl. Ak. 1845, Ixxii. ;
Klitz, Sp. Al(/. 21 ; Rabenht. Alg. i. 36.

STEPHANOGO'NLl, Ehr.— An obscure
genus of fossil Diatomacese.

Char. Frustules resembling those of ilfas-
togonia, but with the apices of the valves
truncate, angidar, and spinous.

Two species found in Bermuda and North
America. S. poh/gona (PI. 18. fig. 30).

BiBL. Ehrenb.' ^e;-. Berl. Ak. 1844, 264;
Kiitz. Sp. Alq. 26; Pritch. /;//. 814.

STEPHANO'MA=Pandorixa.

STEPfLlNOM'ONAS, K.— A genus of
Cilio-Flagellate Infusoria. Free, ovate,
with an anterior circle of cilia, and a single
flagellum. S.locellus; freshwater. (Kent,
Inf. 466.)

STEPH'ANOPS, Ehr.— A genus of Ro-
tatoria, of the family Euchlanidota.

Char. Eyes two, frontal, foot forked;
carapace depressed- or prismatic ; anterior
part of body expanded so as to form a fron-
tal hood ; jaws each with a single tooth.

S. cirratus (PL 44, fig. 28). Carapace
with two posterior spines j freshwater;
length 1-240".

!S. muticus has the carapace without spines
posteriorly, and the eyes have not been
recognized ; whilst <S'. lamellatm has three
posterior spines.

BiBL. Ehr. Inf 478 ; Pritch. Inf. 600.

STEPHANOPYX'IS, Ein-.-A genus of
Dintomaceed = Fi/xiclicula in part.

STEPHANOSI'RA, Ehr.— A genus of
Diatomaceae.

Char. Frustules united into a short fila-
ment, disk with radiating series of minute
puncta and a marginal crown of teeth.
Allied to Stephanodisms and Melosira. On
trees. (Pritchard, Infus. 823.)

STEPIL\NOSPIE^'RA, Cohu.— A ge-
nus of Volvocinese (Confervoid Algse).
S. pluvialis (PL 48. fig. 22) is neai-ly related
to Pandorina, consisting of a large hyaline

STEHEOCAULON.

[ '37 ]

STICTEI.

globe with eiglit biciliatecl green cells,
placed at equal distances on the equator.

liiHL, Cohn, Siff). cV lui/lilc, Zeitschr. iv.
77, Ann. X. II. x. 321, pi. 0 ; Mic. Jn. vi.
131; Kabenh. Alff. iii. 100; iircher, Qu.
Mic. Jn. 18G-J, 110.

STEREOCAU'LON, Schreb.— A genus
of Cladodei (Licheuaceous Lichens). 8,
jjdschale, the most distinct species, is abun-
dant on rocks and stones in mountainous
districts. Thallus greyish and rough, apo-
thecia conglomerated, blackish brown ; sper-
mogonia in little brown heads, near the
apothecia. Other species.

BiBL. Hook. Br. Fl. ii. pt. 1. 237; Tu-
lasue, Ann. Sc. Nat. 3. xvii. 197 ; Enyl. Bot.
pi. -1^^ ; Leiirhton, Lich. Fl. Ii9.

STEREONE'MA, Kiitz. — A supposed
Alga of the family Phasonemere (Kiitzing),
stated by Cohn, however, to consist of the
decaying stalks of Anthophysa. (Kiitz.
Sp. Ah). IGO.)

STE'REUM, Fr. — A genus of Auricula-
rini (Ilymenomycetous Fungi), character-
ized by its coriaceous substance, and even
hvmeuium without bristles, as in Hymeno-
chctte.

The species are numerous, amongst which
Stereum hirsuiutn is one of our commonest
Fungi.

BiBL. Fr. Fp. 548; Berk. Outl. t. 17.
f. 7; Cooke, Handb. 316.

STERIG'MATA.— The term applied by
Tulasne to the filaments forming the pedi-
cels of the spermatia in the Fun«i (PI. 26.
figs. 2, 3).

STERROM'ONAS, Kent.— A genus of
Flagellate Infusoria. Free, elongate, with
two flagella, the longer rigid, the shorter
flexible and vibratile. 8. formicina, in
vegetable infusions, salt and freshwater.
(Kent, Inf. 420.)

STICIIIDIA. — Pod-shaped processes of
the fronds of Florideous Algte, containing
the tetraspores imbedded in them (fig. 157,
p. 236).

STICHOCIL'E'TA, CI. and Lachm.— A
genus of Hypotrichous Infusoria, fam. Oxy-
trichina. Free, elongate, narrowed and
with cirri in front, and with styles and
setae behind, ^S". pedicuUformis \ marine.
(Kent, Inf. lib; CI. & Lachm. Inf.
152.)

STICHOCOC'CUS, Xiig.— A genus of
Palmellacese, consisting of very minute, ob-
long, thin- walled, green cells, single, or usu-
allv arranged in rows. <S'. bacillaris (PI. 3.
fig.' 25), on damp decaying wood, especially

of willows, walls, &c. (Rabenhorst, Fl. Ahj.
iii. 47.)

STICIIOSTE'GIA, D"()rb. (Rhabooi-
DEA, Schultze).— lJ"Orbigny arranged all
Foramiuifera having uniserial or linear
growth under this head as an Order; but,
besides the many straight Nodosarince,
there are several rectilinear forms of other
genera belonging to dilferent Natural
Orders, as Litiiold, Puvonia, ArticuUna, Sec,

STICIIOTRICIIA, Perty. — A genus
of Hypotrichous Infusoria. Elongate, va-
riable, narrowed in front; outer anterior
cilia very long, in a lateral row ; often con-
tained in a cyUndrical carapace.

Several species; salt aud freshwater.
(Kent, l7if. 775; Perty, Lebensf. 153.)

STIC'TA, Ach.— A genus 6f Phyllodei
(Lichenaceous Lichens), with a tough fo-
liaceous thallus, growing over rocks and
trunks of trees, mostly in mountainous dis-
tricts. *S'. jmlmonaria forms large shaggy
fronds of olive-green colour when fresh,
pale-brown when dry, pitted and reticu-
lated ; apothecia mostly marginal, red-
brown. Spermogonia occur scattered on
the upper surface, mostly near the ends of
the lobes.

BiBL. Hook. Br. Fl. ii. pt. 1. 208; Tu-
lasne, Ann. Sc. Nat. 3. xvii. 169, pi. 1 ;
Engl, Bot, pi, 572; Leightou, Lich. Flor.
111.

STICTEI, Fries.— A group of Ilelyel-
lacei (Ascomycetous Fungi), containing

Fig. 697.

Fig, 698.

Stictis versicolor.

Fig. 697. An open disk, emerged on the surface of

wood, hating an irregular border.
Fig. 698. Vertical section of the same.
Magnified 20 diameters.

Fig. 699. Asci and paraphyses from the last. Magni-
fied 20U diameters.

several genera of plants, growing on wood,

3b

STICTINA.

[ 738 ]

STILBACEI.

brandies of trees, &c., bursting througli
from beneath the bark when matiu'e. Stidis
(Cn/ptomt/ces,Ikv\i. ; Propolis, Fr., ^S". Vcff.)
versicolor (figs. 697-600) is common on
wood ; the upper surface of the open fruit
is white, and at length mealy.

BiBL. Berk. Br. Fl. ii. pt. 2. 214 ; Ann.
N. H. vi. ooO; Fries, Sum. Veg. 372.

STICTINA, Nyl.— A genus of Phyllodei
(Lichenaceous Lichens). Thallus variously
lobed or laciniato-lobate ; rhizina3 simple ;
granula gonima of a dark blue-green colour.
(Leiohton, Z«r7/(.i^/. IDS.)

StiCTODIS'CUS, Grev.— A genus of
Diatomacese. S. Hardmanianus, in the
JNIonterey deposit. (Grev. Mic. Tr, 1865,
98.)

STIGEOCLO'NIUM, Klitz.— A genus of
Confervoid Algfe, doubtfully referred to
Confervacefe, growing mostly in brooks,
and composed of delicate branched fila-
ments, drawn out into delicate hyaline
points ; attached to stones aud forming
masses of a mucous or lubricous character.
The jointed filaments are composed of short
cells, possessing bright green contents ; the
entire contents of a cell are converted into
a single spore (with four cilia) and dis-
charged (PI. 0. fig. 5) ; and the cell-wall is
so delicate that it generally vanishes at the
same time. Many species are described by
Kiitzing, formerly regarded as members of
the genus Dkapaenaldia, Avhich differs in
the number of spores produced in each cell,
and in possessing large pi'imary filaments
with lateral tuits of dehcate ones, re-
sembling those of Sfit/eoclonium (fig. 179,
p. 271).

S. jn-otensiim (PI. 0. fi^. 5). Tufts of
filaments 1-36 to 1-60" high, very much
branched and elongated ; primary filaments
1-1800" in diameter, joints equal or three
times as long (Drap. condcnsata, Ilassall).

S. tenue. Tufts about 1-36" to 1-72"
hig'h; filaments 1-21G0" in diam., torulose;
set above with tufts of abbreviated brauch-
le's {Drap. tenuis, Llass. )

<S'. elotuiatum. Filaments very slender,
1-2880" in diam.; branches erecto-patent,
often opposite, subramulose, fkagelliform ;
joints three or five limes as long as broad
(jJrap. elong. Ilass.).

S. nanum. Filaments highly mucous,
very slender, sparingly bninched, branches
acuminate, not usually ciliate ; cells rather
broader than long {Drap. nana, Ilass.).

]5tbl. Kiitz. Sp. Al,/. 352; Tab. P/ii/c.
iii. pis. 1-11; Ilassall, L'r. Ahj. p. 118;

Thuret, Ann. Sc. Nat. 3. xiv. 223, pi. 18 ;
liabenh. Aly. iii. 375.

_ STIG'MA.— The part of the pistil of An-
giospermous Flowering Plants, upon which
the pollen rests to produce its pollen-tubes,
and where the oi'ifices exist leading to the
cavity of the ovary. It is situated either
at or near the summit of the style or its
branches ; or, when this is absent, it is ses-
sile on the ovary. The surface of the stigma
is clothed with papilliform or short tubular
cells, from which a tenacious secretion
exudes at the period when the ovules are
prepared to receive the pollen-tubes. At-
tached by this adhesive fiuid and often
grasped by the papillae the polkm-grains
produce theu" tubes, which make their way
between the papilhe to descend through
the conducting tissue of the style to the
placenta (PI. 40. fig. 30). These papilli-
form cells in a young state often form
favourable subjects for the study of the pro-
toplastic cell-contents, and also of the fiuid
colouring-matter. The forms of the stigma
are exceedingly varied aud sometimes very
elegant; and some of those covered with
coloured hairs form beautiful microscopic
objects. In the Order Oompositos, its cha-
racters are used for the systematic divi=:ion
of the numerous genera.

_ STIGM-F'US, Koch.— A genus of Trom-
bidiua (Acarina). Legs seven-jointed, ce-
phalothorax Avith transverse line ; no eyes.
!S. cruentus, very minute. (Koch, Ucbcrs. ;
Murray, Fc Ent. 124.)

STIGMAPH'ORA, Wallich.

A genus

of Diatomaceie.

Char. Frustules free, naviculoid ; valves
lanceolate, loculale ; kiculi with central and
marginal puncta ; marine. India.

BiBL. Wallich, Tr. Mic. 8oc. viii. 43;
Eabeuht. Ah/, i. 258.

STIG'MATA OF Animals. See Smra-

CLES.

STIGMATIDIUM, Mey.— A genus of
Graphidei (Lichenaceous Lichens). Apo-
tliecia brownish, punctiform or elongate,
immersed, hypothecium colourless, (Leigh-
ton, Lich. Flora, 412.)

STKiONE'MA, Ag. — A supposed genus
of Oscillatoriaceiie, founded up(m wliat has
proved to be the thallus of a genus of
Lichens. See Ephebe.

STILBA'OEI.— A family of Hyphonwce-
tous Fungi, growing upon decaying animal
or vegetable matter, or oji bark or leathery
leaves. Characterized by a receptacle com-
posed of conjoined filamentous or hexagoual

STILBOSrORA.

[ 739 ]

STING.

cells and spores borne singly on the apices
of tree tiIanients,t'oi-minj^ a gelatinous mass.
Some of the Fungi here included are hete-
rogeneous and iniperfoctly studied; for
example, Tiibcrciilurin and Fusariiim are
apparently only imperfect states of other
Fungi, Avhile the more distinct genera ap-
pear to be referable to the family Dematiei.

Si/nopsis of British Genera.

Stilhum. Receptacle stalked at the base?
clavate or capitate at the summit, com-
posed of coalescent, densely crowded, paral-
lel filaments ; spores simple, arising singly
at the apices of free filaments.

Atractium. Stem firm. Head subglo-
bose ; spores fusiform, elongated.

Mi/rothecium. Receptacle at length mar-
ginate. Spores diffluent, oblong, forming a
Sat or slightly convex, dark green stratum.

Tub&rcularia. Receptacle wart-shaped,
globidar or stalked, fleshy, composed of
continuous sterile, and thread-like beaded
fertile filaments. Finally indurated, floc-
cose, with the spores scattered over it, or
falling into powder.

Periola. Receptacle cellular, sessile;
fertile filaments abbreviated, torulose, mixed
with septate lax sterile filaments.

VuhdeUa. Receptacle wart-hke, cellular,
compact, with long, rigid bristles; spores
spindle-shaped, septate, on continuous short
filaments, arising all over the receptacle.

Fmarium. Receptacle wart-like, cellular,
gelatinous; spores spindle-shaped, simple,
somewhat cm-ved, borne on simple filaments
arising all over the receptacle, and forming
a discoid stratimi.

lUusporium. Receptacle wart-shaped,
subgelatinous, difiiueut; spores simple, pel-
lucid, generally with a hyaline envelope,
borne on short filaments.

Epicoccum. Receptacle wart-shaped, cel-
lular, for the most part seated on an eftused
patch ; spores four-sided, cellular, attached
singly to very short, continuous filaments.

yEgerita. "^Spores irregular, disposed in
short moniliform threads at the apices of
flexuous, branched, radiating, compacted
peduncles.

BiBL. Berkeley, Crypt. Botany, 311.

STILBOS'PORA, Pers. — A supposed
genus of Melanconiei (Stylosporous Fungi),
but apparently only consisting of stylospo-
rous fruits of '^Spharice. These grow npon
w^ood, sticks, &c., breaking forth on _ the
surface without any distinct perithecium,

consisting of a nucleus Fig. 700.

composed of aggluti-
nated (septate) stylo-
spores (see Sph-'eria).
BinL. Berk. Jir.
Flor. ii. pt. 2. 356;
An. N. II. vi. 355;

Hookers Jn. o/^ J5o<. Stilbospora macrosperma.
iii. 322; Fries" Sum., f''"""P "^ conceptaclca

T' ~Ao T' ■ bri'aliini? forth on :i frac-

ley. o08: Iresenius, m.-nt oNvood; nat. 8i?:7..

Beitr. S. 31yc. ii. 03 ; The (UtaLlu-d spoi-cs on

Tulasne, An. So. Nat. f^^^Sf """""'^''
4. V. 109.

STIL'BUM, Tode.— A genus of Stilbacei
(Hyphomycetous Fungi), containing a con-
siderable number of species, forming little
shining mildews, sometimes brightly
coloured, on decaying Avood, herbaceous
plants, fungi, &c. The stalk-like stroma is
sometimes villous, sometimes glabrous and
rigid, sometimes pellucid and soft ; it is
formed of conj oined filaments, the free ends
of which bear the spores in a capitulura,
which finally exhibits a gelatinous cha-
racter.

BiBL. Berk. Brit. Fl. ii. pt. 2. 330 ; Ann.
N. H. vi. 432, pi. 12 ; ih. 2. v. 465 ; Fries,
Sum. T'er/. 469.

STII.OPPl'ORA, J. Ag.— A genus of
Sporochnacepe (Fucoid Algje), included by
some authors among the Dictyotacese. There
are two British species, 8. rhizodes and 'S'.
Li/nybyei, characterized by a branched, fili-
form, at first solid, afterwards tubular frond,
the former 6 to 24", the latter 2 to 4" long,
arising from a small naked disk. The fruc-
tification consists of little wart-like bodies
scattered all over the frond, composed of
tufts of moniliform filaments, at the bases
of which are attached either pyriform uni-
lociUar, or tubular septate sporauges. Thu-
ret states that the specimens of *S'. rhizodes
found a certain distance above low-water
mark appear mostly to bear septate, those
always under water simple sporauges, and
those in an intermediate position exhibit
both. The plants of the first kind are of
paler colour than those of the second.

BiBL. Harvey, Mar. Ahj. 39, pi. 7 C ;
Greville, Alg. Brit. pi. 6 ; Thuret, A?in. Se.
Nat. 3. xiv. 238, pi. 38.

STING OF Insects. — The well-known
sting of the females or so-called neuters of
H}-menopterous Insects, as the honey-bee,
the humble-bee, the hornet, the wasp, &c.,
appears to the naked eye to be a single
needle-like organ ; but when examined un-
der the microscope, it is seen to consist of

STINGS.

I 740 ]

STINGS.

three pieces — a short, stout, cylindrico-coni-
cal outer piece or sheath (PI. 34. fig. 14 a),
cleft throughout its length on the under
surface and obtuse at the end, within which
are partly contained two long elbowed setse
or lancets (PL 34. fig. 15, one of them),
thickened and furnished with teeth directed
backwards near the end of one margin, the
other margin sharp and cutting. These setse
play within the sheath, being partially pro-
trusile and retractile, as is the sheath itself.
The poison-apparatus consists of two glan-
dular elongated sacs, either simple (PI. 34.
fig. 14 e,/), or branched as in the humble
bee, &c., and terminating by one (fig. 14f/) or
two ducts, in a muscular reservoir (fig. 14 c),
from which an excretory duct runs to the
base of the sheath of the sting.

The irritation produced by the sting of one
of these insects needs no remark. It does not.

Fig. 701.

however, serve a merely defensive purpose,
but is used also to paralyze the prey, so that
it may be kept in store for future use.

The sting represents a modified ovi-
positor.

BiBL. Lacaze - Duthiers,
Aim. Sc. Nat. 3. xii. xiv.
&c. ; AVestwood, Intrud. ; Sie-
bold, Vergl. An.

STINGS OF Plants. —
These are epidermal struc-
tures, consisting of large hairs,
with a bulbous base more or
less included in a cellular
coat,'and attenuated upwards.
In the sting of the nettle the
apex is expanded into a little
bulb, which is broken oft" when Kettlt
the sting is lightly touched ,j^ go diams.
(PI. 28. fig. 8). Young stings

stinging hair of

Pig. 702.

Fig. 703.

Fig. 704.

Fig. 702. Gastric mueous gland with cylind^r-opitlK^liiim, from the pylorus of a dog. a, principal cavity;
6, tuBu)ar processes arising from it. Magnified <iO diameters.

Fig. 703. Gastric peptic gland from the middle of the stomach, a, principal cavity; 6, primary, and c, terminal
branches arising from it. Magnified 60 diameters.

Fig. 704. Portions of a terminal branch, the upper representing a longitudinal, the lower a transverse section,
a, basement membrane; b. large cella in close apposition with it; c, smaller epithelial cells surrounding the
cavity.^ Magnified 350 diameters.

STIPA.

[ 741 ]

STOMATA.

exliibit the Rotatiox. Stings occur not
only ill the nettles (Urfica), but in the
cultivated Loasacene {Loa/^a, Bartonia, Sec),
and of much larpn- size in some exotic
Urticacete and Euphorbiacese.

See Hairs, page 378.

STI'PA, Linn. — A genus of Graminacefe.
The fibres of the culms of -S'. tenacissima
are used in the manufacture of paper.

STOMACH.— The glauds which secrete
the gastric juice, or the peptic glands, are
tubular, and placed perpendicularly beneath
the surface uf the mucous membrane, and
extending as deeply as the muscular coat of
the stomach.

They vary in length from 1-60 to 1-12",
are cylindrical, somewhat narrowed towards
the closed end, which is rounded or some-
what inflated. The lower third is wavy or
spiral, especially in the glands occupying the
pylorus ; some of them also give on a ctecal
Dranch.

The peptic glands consist of a delicate
basement membrane, lined in the upper
third with cylindrical epithelium, the lower
portion being tilled with large, pale, poly-
Fig. 705.

Perpendicular section of the pyloric portion of the
stomach of a pig. a, glands ; b, muscular layer of the
proper mucous membrane; c, submucous tissue with
the oritices of divided ressels ; d, transverse muscular
layer; e, longitudinal ditto; f, serous coat. Magnified
30 diameters.

gonal, finely granular cells, not arranged in
a laminated form.

In many animals the gastiic glands are of
more complicated structure than in man, and

two distinct l<inds exist — in one, secreting
mucus, tlie tubes being lined with cylin-
drical epithelium; wliilstin tlie other, wiiich
secretes gastric juice, rounded epitlidi <\
cells occur, and the walls tu'e expanded at
intervals.

Closed follicles resembling the solitary
glands of the small intestines are met with
in the stomach ; they are inconstant, how-
ever, and variable in number.

The stomach is lined by cylindrical epi-
thelium.

BiBL. KoUiker, Mik. An. ii. 1.37, and the
Bibl. therein ; Todd and Bowman, Phi/s. An.
^•c. ; Briuton, TodxVs Cycl. An. ^- Phys. Art.
Stomach ; Klein, Strieker'' s Hist. i. 1543.

STOM'ATA (plural of Stoma).— The
name applied to the structures which con-
stitute the passages of communication,
through the Epidermis of plants, from the
intercellular passages to the external air.
They occur almost exclusively on the green
parts of plants, and are usually absent from
the epidermis of roots, and the siu'face of
all structures growing under water. The
lowest classes which present them are the
Liverworts and Mosses, where, however,
they are limited to a few kinds, and in the
former present a pecidiar organization. In
the Ferns they are distributed just as in
the Flowering Plants, where they occur
principally upon the leaves (fig. 706),
especially upon the lower face, but ex-
tend also over the green shoots, the parts
of the flower (fig. 200, page 296), and even
into the interior of cavities, as on the epi-
dermis of the replum of Cruciferre (wall-
flower), and still more remarkably on the
epidermis of seeds (skin of the walnut).

In the Liverworts the stomata occur on
the fronds and receptacles of certain genera
{Marehanlia, Feyatella, &c. &c.). In Mar-
chantia (fig. 447, p. 489), they are somewhat
circular orifices in the epidermis, guarded
by cells arranged in three or fom* tiers. In
the Mosses they are met with on the apo-
physes or thickened summits of the setas
bearing the capsules, as in Funaria (fig. 262,
page 343). The structures here resemble
those in the higher pkint.j, as is the case
also with those on the leaves of Ferns.

In the Flowering Plants the perfect sto-
mata appear as roundish or sometimes
squarish chasms in the epidermal layer,
occurring regularly at the meeting angles
or sides of four or more epidermal cells, the
chasm forming an orifice leading down to a
subepidermal intercellular space, and guar-

STOMATA,

L 742 ]

STOJIATA.

Fig. 706.

ded a little below the upper edge, more
deeply, or even at the bottom, by usually
two semilunar cells, applied together by
their flat faces, but not coherent, their con-
vex surfaces adhering firmly to the sides
of the epidermal gap. According as the
two stomatal cells —
pore-cells or guard
cells — are distended
or coUapsed, their
flat faces approacli
or retreat from each
other, in the latter
case leaving a slit-
like orifice leading
from the outer pas-
sage into the subepi-
dermal space. Some-
times the guard
cells are four iu
number, in which
case they either form
two tiers, as upper
and lower (Prote-
aceae, e. y. Hake a, Epidermis of the WWto

Protca, &C.), or thev ^''y ^it^^ stomata si (lower
li V ' surface).

are m the same hne ..^ •„ imAj-

, HIP Maenined 100 diameters.

and parallel, lorm-

ing inner and outer guard cells {Ficns
elastica). In certain coriaceous leaves the
stomata are placed on the sides of pits ex-
cavated beneath the surface of the leaves,
as in Dasylirion longifolium and Kerium
Oleander.

A considerable difi'erence exists between
the appearances presented by vertical sec-
tions of the epidermis of leaves made so as
to pass through the stomata. In young
leaves the guard cells are little (if at all)
below the general level of the epidermis ; and
the same is the case with the perfect forms
of various herbaceous plants in which the
leaves are of mtunbranous texture. In other
cases, as iu the Hyacinth, Iris, Narcissus,
Equisetum, Sec, the guard cells are found at
a very early period quite beneath the layer
of epidermal cells, attached as it were
under the passage communicating with the
air. The same occurs very frequently in
the stomata of coriaceous leaves, as in Aloe
(PI. 48. fig. 2-2),Fici(s, Ci/cas, Halcea, Protea,
&c. In other instances also in leathery
leaves, the guard cells appear more or less
elevated ahore the general level of the
epidermal cells, as in some species of Leii-
cadeiidron, Orevillca, &c. It is important to
observe that in the cases where the guard
cells are sunk in the orifice of the epidermis,

the upper margin of the orifice, formed by the
borders of the sm'rounding epidermal cells,
sometimes becomes elevated and even con-
verted into a kind of perforated dome (PI.
48. fig. 2'2) by development of the cuticular
layers (see Epideemis). This might be
mistaken for the stoma itself. The same
cuticular substance is often developed in
matiu'e leaves, not only down over the walls
of the stomatal passage, but over the guard
cells, and thence more or less into contiguous
intercellular passages. This maybe observed
iu Euphorbia Capid-Mediisa; , Hellebortis
niijer and viridis, Behda alha, Asphodelus
htteus, and Cereus, some Aloees, &c. Gas-
parini obtained these connected processes of
cuticular substance, iu the form of an
isolated coherent piece, by boiling epidermis
in nitric acid, which dissolved the adjoining
cell-walls : these he mistook for peculiar
organs, and called them cystomes. Hooker
has described a remarliable form of stomata
in the parasitical plant Myzodendron.

Iu those plants in which the epidermis
becomes infiltrated with siliceous matter, the
walls of the stomatal pore and the guard
cells become imbued with it, and a sili-
ceous skeleton of the structure remains after
the organic matter has been removed by
nitric acid and burning (PI. 48. fig. 29).
This is readily seen in the Equisetacea3,
especially E. hyemale, also in the Grasses.

The mode of development of the stomata
appears to be uncertain. Mohl and other
authors assert that the guard cells origi-
nate from one of the cells of the subepi-
dermal tissue, which is pushed up into a
vacancy formed by the separation of the
epidermal cells at certain points. This cell
is next divided into two, which become
free from each other in the line of the now
partition then formed. Niigeli and others
assert that the guard cells are originally
constituent cells of the epidermal layer,
which become subsequently displaced down-
wards (or upwards), and undergo special
development analogous to that just de-
scribed. In the Iridaceas, Equisetaceoe, and
some other plants, the process is more com-
phcated.

The stomata are generally largest upon
succulent leaves, smallest on hard and
leathery kinds ; their form and nuudjer are
most varied, both in different plants and on
different jiarts of the saine plant. Tliey
abound most on the lower face of loaves ;
but it has been mentioned that they are not
found on submerged organs, and on floating

STOMATA.

[ 743 ]

STRIATELLA.

Ipavos thoy occur only upon tlio upper face.
The larger kinds ure more scattered on
a given surface ; the smaller occur closer
together: this depends, of course, on the
fi^eneral character of the epidermal and sub-
jacent tis,-;ue. The numbers have been
estimated upon the surfaces of many leaves,
of which a few examples may be given :
thus a sq[uare inch contains, on the

Uppor surface. Lower surface.

Carnation 38,500 38,500

Garden Flag ... . 11,572 .... 11,572

Ilouse-leek .... 10,710 .... G,U00

Tradescanfia .... 2,000 .... 2,000

Mi.stletoe 200 . . . . 200

IIollv 0 . . . . 03,600

Lilac 0 ....1(;0,000

Tine 0 . . . . 13,000

Laurestinus 0 90,000

BiBL. Geiieral Works on Struct. Botany ;
Mirbel, Mem. Ac. lioif. France, xii. ; Gas-
pariui, Nuove ric. s. strutt. cl. Cistomi, 1844;
Garreau, Ann. Sc. Nat. 4. i. 213 ; Hooker,
Flora Antarct. i. 291 ; Biscoe, Mn. Mic. Jn.
viii. 31.; Hohnfeldt, ^o!!. Centralhl. 1880, i.,
Jn. Mic. Soc. 1881, i. 71 (undergTouucI) ;
Prantl, Flora, 1872 ; Stein, Bot. 103.

STOMATA or Stigmata of Animals.—
These are minute rounded spaces, left be-
tween the epithelial cells of the capillary
blood-vessels, lymphatics, and of the serous
membranes. Great importance has been
attributed to them, as allowing the escape
of the corpuscles and liquid into the sur-
rounding tissues. This may occur when the
vessels are congested and distended; but
not in the normal state, for the finest injec-
tions do not escape through them. They are
best seen in silver-stained preparations.
(Frev, Hist, and the Bibl.)

StOMATOP'ORA=ALECTO.

STONES OF Feuits, such as cherries,
plums, Sec, aftbrd excellent materials for
sections, showing extreme development of
the woody Secondaky deposits of vege-

STORTHOSPn.E'RA, Schulze.— A glo-
bular Arenaceous Foramiuifer with a short
blunt spike. German Ocean. (F. E. Schulze,
Commiss. wiss. Un.deutsch. J/eere,1875,113.)

STRIA'RIA, Grev.— A genus of Dictyo-
siphonacese (Fucoid Algae), nearly related to
Punctariaceas, having a branched, filiform
pale olive, tubular frond, ari.sing from a
shield-shaped naked disk. The walls of the
tube are membranous, and the cavity with-
out septa. >S'. attenimta (fig. 707) grows from

Striaria attenuata.
Fig. 707. Part of a frond. One-third of the nat. siz«.

Fig. 708.

Fig. 709.

striaria attenuata.
Fig. 708. A fragment with sori. Magnified 5 dinms.
Fig. 709. Section of a fertile branch, with sori. Mag-
nified 25 diameters.

3 to ] 2" high. The branches are attenuated
towards each end, and marked with rings
consisting of clusters of simple sporanges
(spores) (fig. 708), sometimes accompanied
by filaments (fig. 709).

BiRL. Harv. Mar. Ahj. 41 ; Grev. Ahj. 54.

STRIATEL'LA, Ag.— A genus of Dia-
tomaceae.

Char. Frustules with a stipes attached to
one angle, depressed, tabulate ; with longi-
tudinal uuint^jrrupted vittje, apparently
thickened at each end. Marine.

The vittse appear as dark lines ; no trans-
verse striae are visible under ordinary illumi-
nation.

*S'. unijnmctata (PI. 17. fig. 20), Frustules
in front view quadrangular, often broader
than long, lateral margins subulate ; valves
narrowly lanceolate ; stalk elongate, simple,
filiform and thickish. Length of frustules
1-450 to 1-280".

STRIGULA,

[ 744 ]

STYLONICHIA.

BiBL. Kiitz. 7?««//. 125 : Sp. Ak/. 114;
Rabenbt. A/(/. i. 307 ; Grimow, M. M. J.
xviii. 171.

STKIG'ULA, Fries.— A genus of P^Te-
nodei (Licbenaceous Liebens), containing
one Britisb species, S. Bahinc/tonii, growing
ou tbe leaves of box and otber evergreens.
Tballus subepidermal ; asci containing eigbt
cymbiform triseptate spores.

BiBL. Leigbton, Lkh. Fl. 498; Berk.
Enf/. Bot. Supp. pi. 2957.

STROMBID'IUiM, CI. & Lacb.— A ge-
nus of Peritricbous Iufasoria,fam. Halterina.

Char. No setse for leaping, essentially
swimmers. 8 species ; marine and fresb-
Avater. (CI. & Lacbm. Inf. 371 ; Kent,
Inf. O.-U.)

STKOMBIDINOP'SIS, Kt.— A genus of
Heterotricbous Infusoria. Free, ovate,
ciliated ; anterior cilia longer, forming a
wreatb of one or more turns. S. (/yrans ;
fresbwater; lengtbl-350". (Kent, //(/.614.)

STRONG YLID'IUM, Sterki.— A genus
of Hypotricbous Infusoria. Like Urolepttis
piscis, but witli a tbicker twisted bodv, and
frontal and anal styles. (Kent, Inf. 779.)

STRON'GYLUS, Miill— A genus of
Nematoid Entozoa. Tbe species are very
numerous. S. jiergraciUs is tbe cause of tbe
grouse-disease. S. saju/visiu/n is allied to
Anchylosto7na, inbabits tbe buman small
intestine, sucking tbe blood and producing
ansemia. (See tbe Bibl. of Entozoa, and
Dounon, Parasites.)

STRONTIA OR STRONTIAN. — Tbe
crystals of tbe sulpbate of tbis eai'tby base
are figured in I'l. 10. fig. 18, to contrast witb
those of tbe sulpbates of barvta and lime.

STRUTHIOP'TE-
RIS, Willden. = 0??(7-
clea, pt. — -S'. (Onoclea)
f/erma?iica, fig. 710.
■ STRYCHNlNE,or
Strychnia. See Al-
kaloids, p. 31.

STYLOBIB'LI-
UM, Ebr. — A genus
of fossil Diatomacefe.
C/iar. Frustules
circular, single, com-
pound ; valves con-

tiguous,

in a single

row, like tbe leaves of

Struthiopteris germanica.

Portion of a pinna with the

, , ., . rolled margins coverine the

a book, tbe nmer ones gori.

with a large median Magnified 40 diameters.

aperture (?),tbe outer

not being perforated but sculptured.

S. c7?/;je2<s (PI. 18. fig. 50 a, />) ; S.divisum

(%. 50 (?) ; S. eccetitricum (fig. 50 (f). It is
uncertain whether the so-called inner valves
are merely hoops, or tbe valves of imperfectly
separated frustvdes ; also whether tliey are
perforated or not, for neither Ebrenberg nor
Kiitzing can be relied on for distinguishing
aperforation, as evidenced by their erroneous
description of tbe structure of the valves
of Piiinularia, Grammatophora, and many
other IJiatomacese.

Three species are described, occurring in
America and Siberia. The sculpturings
upon the outer valves consist of radiating
or excentric curved lines.

Bibl. Ebr. Ber. Berl. Ak. 1845; id.
Mikroff.; Kiitz. Sp.Alff. Id', Rahenht. Alg.
i. 302.

STYLOB'RYON=Dmoi/7/on pt.

STYLOCHO'NA, Kt.— Like Sjnrochona,
but with distinct stalks. 2 species ; on
Kehalia and Gammarus. (Kent, Inf. 662.)

STYLOCHRY'S'ALIS, Stein.— A genus
of Flagellate Infusoria. Ovate, pedicled ;
flageUa 2, equal ; two lateral pigment-bands ;
freshwater. *S'. parnsita, on Eudorina ele-
gans. (Kent, Inf. 405.)

STYLO'COLA, De From.— A genus of
Peritricbous Infusoria. Body as in Tagi-
nicola, but attached to tbe sheath by nume-
rous fibres. Two species; freshwater. (Kent,
Inf. 730.)

"STYLONE'THES, Sterki.— A genus of
Hvpotrichous Infusoria. S. tardus. (Kent,
Inf 782.)

■STYLONICHIA, Ebr.— A genus of Hy-
potricbous Infusoria, fani. Oxvtricbina.

Char. Body ciliated, and furnished with
styles and hooks.

In tins genus, transverse and longitudinal
division, gemmation, and tbe encysting pro-
cess have been observed.

S. mgtilus=Kerona mijtilns, D. (PI. 31.
figs. 27, 28). Body wliite, hyaline at each
end, flat, oblong, slightly constricted in tbe
middle, dilated at the obbque fore part ;
fresbwater; length 1-240 to 1-100".

S. pustuJata-=Kerona pnsful. B. (PI 31.
fig. 26). Body white, turbid, oblong, witli
a median ventral band of books ; fr. wat. ;
length 1-144".

S. histrio (PI. 31. fig. 29). Body wbite,
elliptical-oblong, hoolfs aggregated into an
anterior heap ; no setse ; fr. wat. ; length
1-290 to-1220"; probably a variety of >S'.
pnstidata.

S. lanceolata (PI. 31. fig. 30). Body
lanceolate, pale green, obtuse at tbe ends;
central surface flat ; hooks acervate near

STYLOPLOTES.

[ 745 ] SUDORIPAEOUS GLANDS.

the mouth ; styles none ; fr. wat. ; length
1-140 to l-i'O''.

BiBL. Ehr. Inf. 870 ; Stein, Inf. ; Clapa-
mle et Lachni. 'inf. lo4; Kent,'//?/". 71)0.

STYLOPLOTES, Steiu= Sti//oni,hia pt.

STYXOSPOR'EL— These fuiigi were for-
merly included in the Coniomycetks; but
their external resemblance to the Pyreno-
MYCi^.TEs, of which they are indeed forms,
makes it desirable to give them a separate
name.

STY'LOSPOEES.
— Stalked spores of
Coniomycetous Fun-
gi, usually compound
or septate, then pro-
bably consisting of a
row of independent
spores connected by
an adherent parent
sac — thus, structur-
ally, metamorphosed
asci ; they are some
times appendaged

above (fig. 711) (see Stylospores of Pestalozzia.
Spores and OoNIO- Magnified 200 diameters.
MYCETES).

STY'SA'XUS.— A genus of Dematiei
(Mucedinous Fungi), characterized by a
stem consisting of an aggregation of threads,
bearing above at their extremities simple or
necklaces of spores. S. C(qmt-Medus(P.
(tig. 346, p. 406).

Fig. 712.

SUBLIMATION.— The npplication of
this process in tin; detection of arsenic and
antimony is alluded to at p. 7.3 ; but its
utility has been further shown in regard to
several other inorganic and organic sub-
stances— a little of the substance being
placed in a cup-like hollow in a piece of
platinum-foil, a cover laid on, and heat
applied until fusion and sublimation takes
phace, when the characteristic crystals are
found (Alkaloids).

BiBL. Guy, Phann. Jn. 2. viii. & ix. ;
Helwig, D. Mikr. in d. To.cicologie, 1865,
64 microphotographs.

SUCCINIC ACID.— This acid, which
occurs in amber, in all fermented liquids,
and in the contents of Udi inococcns-cjsts,
is pretty soluble in water, readily in hot but
with difficulty in cold alcohol, and but little
in ether. The ciystals belong to the ob-
lique prismatic system, and are represented
in PL 11. fig. 21.

BiBL. That of Chemistry.

SUDOEIP'AROUS GLANDS.— These
organs secrete the perspiration.

They are found in most parts of the skin,
but in variable numbers in difierent locali-
ties. Thus it has been estimated that 417
exist in a square inch of the skin of the back
of the hand, 109-3 in an inch of the outside,
and 1123 in the inside of the forearm, and
2736 in an inch of the palm of the hand.

Each gland consists of a long tube coiled

Fig. 713.

a

Fig. 712. A sudoriparous gland, with its blood-vessels, a, proper gland; 6, duet; e, blood-Tessels of a gland
Magnified 35 diametera.

Fig. 713. Portion of the tube foiming a sudoriparous gland from the hand. a, areolar coat ; 6, epithelium ;
c, cavity. Magnified 360 diameters.

SUDORIPAROUS OLANDS. [ 74G ]

SYCAMINA.

into a knot near the closed end, -nliicli is
situated in the subcutaneous cellular tissue,
and forms the gland proper, and a straight,
undulate or spiral duct, which traverses the
slan perpendicularly, to terminate upon its
surface between the papilte.

In the glands of the axilla, the portion
of the tube forming the gland proper is
branched ; and sometimes the branches ana-
stomose.

Fig. 714,

/

a

Portion of a tube with a muscular coat, from the Bcro-
tnm. a, connective tissue ; 6, muscular layer ; e, epi-
thelial cells, filling the tube and containing yellow
granules. Magnified 350 diameters.

The coiled portion or proper gland is sur-
rounded and permeated by an elegant plexus
of capillaries ; and some of them are sur-
rounded by a capsule of connective tissue
with spindle-shaped cells.

The tube of the glands exhibits two forms
of structure. In one of these there is an
outer coat of indistinctly fibrous connective
tissue with elongated nuclei, sharply defined
internally by probably a basement mem-
brane, this being lined with one, two, or
more layers of polygonal pavement-epithelial
cells, mostly containing fat-globules and
pigment-granules.

In the other form, the fibrillation of the
connective coat is tolerably distinct, the
fibres longitudinal, sometimes also with an
inner, delicate transverse layer, and both
containing nuclear elastic fibres ; and within
this coat is a layer of longitudinal, unstriped
muscular fibres.

The portion of the ducts traversing the
cuticle is spiral.

It is by no means an easy matter to ob-
tain the sudoriparous glands in the entire
state. The skin of the palm of the hand or
the paw of a dog is best for the purpose \
and before making sections with a Valen-
tin's knife, the structure should be mace-
rated in a mixture of 1 part nitric acid and
2 of water, or in solution of carbonate of
pota.sh.

BiBL. Koliiker, Mik. An. ii. ; Todd and
Rowm.an, Thxjs. An. ; J3iesiadecki, Strieker's
Hist. ii. 238.

SUGAR. — This substance is liable to
fraudulent adulterations; and the coarser
kinds of brown sugar contain many im-
purities, such as Acari, fragments of the
cane, &c. Starch and flour are used to
whiten and give dryness to inferior moist
sugar ; and these may be detected by the
microscope (Starch).

The crystals of sugar of milk are repre-
sented in PI. 10. fig. 12 ; and those of dia-
betic sugar in fig. 13. (Ilassall, Food ^c.l2;
and the Bibl. of Chemistry.)

SURIREL'LA, Turpin.— A genus of
Diatomacea3.

CJiar. Frustules free, single, ovate, ellip-
tical, oblong, cuneate or broadly linear in
front view ; valves with a longitudinal
median line or a clear space, the margins
winged, and with transverse or slightly
radiating canaliculi or tubular striae.

It appears that in the valves the margins
of the depressions are fused together to
form tubular channels open at the ends.

S. hi from (Ehr. 1833 = 6'. biseriata, Rrdb.
and Smith) (PI. 17. fig. 22). Frustules in
front view broadly linear, with rounded
angles ; valves elliptic-lanceolate, somewhat
obtuse ; al?e and canaliculi distinct ; fresh-
water ; length 1-180 to 1-9G".

S. gemma (PI. 17. fig. 21). Frustules
ovate; valves elliptic-ovate ; canaliculi nar-
row, inequidistant ; marine ; leiigth 1-240".
S. splendida. Frustules ovato-cuneate,
ends rounded ; valves ovato-lanceolate ; alfe
and canaliculi distinct; freshwater; len"-th
1-100".

Bibl. Smith, Br. Diatom, i. .30 ; Kiitz.
Bac. 59, and S^j. Ala. 34 ; Rabenht. Ala. i.
51.

SWARMING.— This term has been ap-
plied, from comparison with the swarmino-
of bees, to the remarkable oscillating
crowding movements of Ihe spores of Con-
fervae &c. while free in the cavity of the
parent cell and preparing to break fortli.

The spores are hence often called "swarm-
ing-spores." See IIydrodictyon.

SYCAMI'NA, V. Tieg.— A genus of
Volvocinea?, composed of very minute
spherical, biciliated cells, associated in laro-e
numbers to form a mulberry-Iilie revolvino-
mass, the protoplasm being- black or brown,
sometimes violet or reddish. S. niffrcscens,
found at the bottom of ponds and aquaria,
forming a dark deposit, and producing the

SYENITE.

r 747 ]

SYNDENDRIUM.

decomposition of the organic m.itter.
Reproduction by fission, and formation of
resting' spores. (V.Tieirliem, />»//. >S(ic. Hot.
Fi: 1880. 073; Jn. Mic. Soc. 1881, i. 07.)

SYENITE. See Rocks.

SYMBIOTES = Chorioptes.

SYMROLOPH'ORA, Ehr.— A genus of
Diatomacea?.

CJinr. Frustules single, disk-shaped, with
incomplete septa radiating from the solid
angular centre, and intermediate bundles
of radiatinir lines. Marine and fossil.

-S'. Trinitafis (PL 25. tig. 0). Valves
with a triangular umbilicus, the transparent
margins of which are crenulate, the rest
of the disk covered with six bundles of
very iine radiating lines. Diameter 1-230".
America.

S. acuta (Tl. 18. fig. 54) ; S. micrasterias
(fisr. 55) ; >S'. peiifas (fig. 5G).

JBiBL. Ehr. Ber. Berl. Ak. 1844, 74;
Kiitz. Sp. Alq. 131.

SYMPIIYOSI'PHON, Kiitz. = Sci/to-
nema pt.

SYM'PLOCA, Kiitz.— A genus of Oscil-
latoriacefe (Coufervoid Algfe), perhaps not
distinct from Symphyosiphon.

SYNALIS'SA.— A genus of Collemei
(Collemaceous Lichens), somewhat resem-
blinsr Lichina, but with open apothecia.
(Leio-hton, Licit. Fl. 13.)

SYNAP'TA, Eschsch.— A genus of ver-
mifoiTU Echinodermata.

The species of Si/iiapfa, which are not
British, are of special microscopic interest,
on account of the presence in their skin of
remarkable anchor-shaped calcareous spi-
ciUa, the bases of which play in perforated
plates. These are situated upon minute pa-
pillae of the skin, and serve to aid in loco-
motion and adhesion.

EiBL. V. d. Hoeven, Zool. i. 150 ; Vogt,
Zool. Briefe, i. 168 ; Quatrefages, Ann. Sc.
N. 2. xvii. 19 ; Gegenbaur, Verr/l. An. 216 ;
Herapath, Qir. Mic. Jn. 1865, 1.

SYNCII/E'TA, Ehr.— A genus of Rota-
toria, of the family Hydatiusea.

Char. Eye single, cervical, rotatory organ
furnished with styles; foot forked; jaws
each with a single tooth.

Some of the species are furnished with
one or more so-called crests, which in some
appear to correspond to the calcar.

S. baltica (PL 44. fig. 20). Body ovate ;
rotatory lobes four ; styles four ; a single
median sessile crest; marine; length 1-108".
Phosphorescent. Three other species. (Ehr.
Infus. 436.)

SYNCniT'RIUxM, De By. & Woronin.—
A genus of parasitic Unicellular Alg;e,
allied to Ciiythidium, found under the
epidermis of the loaves of Tara.ractnn and
Succisa, and composed of aggregated orange-
yellow cells, enclosed in an envelope, form-
in"- sori.

BiBL. Rabenht. A/r/. iii. 284.

SYNCORY'NE, Ehr. (parti).— A genus
of Corynidaj (llydroida).

BiBL. Allman^ Ann. K H. 1864 ; Hincks,
Hyd. Zooph. 48.

SYNCRYP'TA, Ehr.— A doubtful genus
of Volvocinefe (Confervoid Algfe), composed
of organisms consisting of a hyaline spherical
gelatinous envelope, enclosing a number of
ovate green bodies placed at the periphery,
and sending out a pair of free vibratile cilia
from the surface of the envelope. Green
bodies not attenuated at the posterior ex-
tremity ; no eye-spot. S. Volvox (PL 7.
fig. 14 J), globe 1-576" in diameter, bodies
1-2880" long; freshwater. This object,
which we have observed in company with
those represented in figs. 14 a, 31 and 32 of
the same plate, is most probably a young
specimen of either Volvox or Pandorma.
Kent places it among the Flagelliform In-
fusoria.

BiBL. Ehr. Inf. 00 ; Kent, Inf. 413.

SYNCYC'LIA, Ehr.— A genus of Diato-
mace«.

C/iar. Frustules cymbelliform, united in
circidar bands, immersed in an amorphous
gelatinous substance. Marine.

The nodules appear to be the same as
those of Cymhella.

S. salpa (PL 19. fig. 14). Frustules
semiovate, unstriated (ord. ilium.), com-
monly six together, united into a ring ; en-
dochrome bright green.

S. quaternaria. Frustules two or four
together ; endochrome yellow or reddish ;
length 1-860".

BiBL. Ehr. Inf. 233; Ber. Berl. Ak.
1840, 32 ; Kutzing, Sp. Ahj. 61 ; Rabenht.
Ah/, i. 97.

SYNDEN'DRIUM, Ehr
Diatomaceaj.

C'liar. Frustules single, subquadrangnlar,
destitute of a median umbilicus ; valves
unequal, slightly . turgid — one smooth, the
other with numerous spines or little horns
branched at the ends, situated upon the me-
dian flat portion, the margins being free
from them.

S. diadema (V\. 18. fig. 59). Frustules
lanceolate ; spines five or six, bifurcate or

A genus of

SYNECIIOCOCCUS.

[ 748 ]

SYNTETHYS,

tufted at the end, as loii": as the frustules
are broad. Breadth 1-1150". Found in
Peruvian guano.

BiBL. Ehr. Ber. Berl. Ahtd. 1845, 155;
Kiitz. Sp. Ah/. 141; Pritchard, Infus. 8GG.

SYNECHOCOC'CUS, Nag.— A genus of
Unicellidar Algae.

Char. Cells minute, oblong, single or eon-
joined in rows of 2-4; dividing in one di-
rection only; endochrome seruginous or
yellowish.

S. (enu/inosus (PI. 3. fig. SH). Common
on damp rocks and banks. (Rabenht. Alt/.
ii. 59.)

SYxNE'DEA, Ehr.— A genus of Diato-
macepe.

C/iar. Frustules prismatic, rectangular,
or curved ; at first attached to a gelatinous,
sometimes lobed cushion, subsequently often
becoming free; valves linear or lanceolate.

The valves usually exhibit a longitudinal
line, with a dilated median and two termi-
nal nodules ; they are also generally covered
with transverse striae ; in some species the
median line and appearance of a median
nodule correspond to a clear space, free
from the transverse striffi.

Species very numerous.

S. radians, Sm. {splendens, K.) (PL 17.
fig. 23 a, b, c). Frustules elongated, in front
view dilated and truncate at the ends ;
valves gradually attenuated from the mid-
dle to the obtuse ends. Freshwater ; com-
mon; length 1-70". Frustules radiate upon
the cushion.

S. ftdf/ens (Linnophora fuhj. K.) (PI.
17. fig. 24). Frustules linear ; valves slightly
dilated in the middle and at the rounded
ends, arranged in a fan-shaped manner upon
tbe branched cushion. Marine ; length
]-120".

8. capitata (PI. 17. fig. 25). Frustules
linear, truncate, ends slightly dilated; valves
linear, ends dilated into a triangular head.
Freshwater ; length 1-GO".

BiBL. Smith, Br. Diat. i. 69; Kiitz.
Sp. Ah/. 40; Rabenht. AI;/. i. 126; Gru-
now, M. M. Jn. xviii. KJG.

SYN'GAMUS, Lieb.— Agenus of Nema-
toid Entozoa. S. frachcaJis is very common
in the trachea of poultry, producing the
"gapes." (Dujardin, i/f'/«H'/;^/(f',s, 260; Sie-
bold, Wiegmann^s Arch. 1835; Cobbold,
Paras?)

SYNOVIAL MEMBRANES.— In minute
structure these resemble serous membranes.

Synovial membranes are occasionally fur-
nished with appendages, some of which

contain fatty tissue, others abound in capil-
laries and form fringes where the synovial
membrane is attached to the articular car-
tilages. The latter consist of a basis of
indistinctly fibrous connective tissue, co-
vered by the sj'novial e])ithelium, with a
few fat-cells, sometimes isolated cartilage-
cells, and the capillaries. Attached to their
margins are flattened, conical, stalked,
smaller appendages (fig. 715), seldom con-
taining blood-vessels, and composed of indi-
stinctly fibrous areolar tissue, with scattered
cartilage-cells, and a thick epithelial layer ;
while some of the smaller ones consist
almost entirely of epithelial cells or of
areolar tissue.

Fig. 715.

From he synoyial membrane of a finger-joint.

A. Two appendages of the synovial ]irocesses. a,
areolar tissue in its axis; h, ipithelium of the free
margin : c, that eontinuons with the epithelium of the
processes; d, cartilage-cells. Magnified S.'iO diameters.

B. Four ejiithelial cells froiQ the synovial membrane
of the Itnec-joiut, one of them with two nuclei. Magni-
fied 350 diameters.

BiBL. Brinton, Todd's Cyd. An. ^- Bhi/s.
art. Serous Membranes ; Albert, Strieker's
Jlisf. iii.

SYN'TETHYS, Forbes.— A genus of
Tunicate Mollusca, of the family Botryllidfe.

Cliar. Mass sessile, gelatinous, forming a
single system ; animal sessile, ha^^ng simple

SYNURA.

[ 749 ]

TABELI.AEIA.

orifices, without rays. One species : S, Jle-
bri'ilicus,

BiBL. Gosse, Mar. Zool. ii. 34.

SYNU'EA, Ehr.— A doubtful genus of
Volvocineiio (Coufervoid Algfe), consistiug
of a number of oblong corpuscles attached
together by their prolonged iiliform pos-
terior extremities to form a globe ; Hagella
two ; no eye-spot. In S. Uvella the corpus-
cles are yellowish, the tails three times as
long as the bodies ; diameter of globes
1-290". See Vol vox. (Ehi-. /«/. 6 ; Kent,
Inf. 411.)

"SYRINGID'IUM, Ehr. — A genus of
Diatomacea}.

Char. Frustules single, terete; valves acu-
minate at one end, two-horned at the other.
Marine.

S. bicorne (PL 18. fig. 32). Frustules
oblong, smooth, not striated, turgid in the
middle, one end attenuate, with two slight
constrictions, and acuminate, the other sub-
globose, tursrid, and with two horns. Length
1-370". Coast of Africa.

S. pahemon (PI. 18. fig. 33).

BiBL. Ehr. Ber. Berl. Ah 184.5, 365;
Kiitz. Sp. Alg. 32 ; Pritc-hard, Inf. 866.

SYRINGOSPH^'RID^, Duncan.—
An extinct Order of Rhizopoda. Free,
globular, sometimes 3" in diameter, consist-
ing of congeries of tubes (1-1000 to 1-300
inch), in radial groups, with an iuterradial
reticulation of inosculating tubes, some of
which appear at the sm-face. Syringo-
sphcera, 5 species, and Stuliczkaria, 1 species,
Triassic (?), N. India, known as " Kara-
koram Stones."

BiBL. Duncan, Ann. N. H. 5. ii. 297;
Yarkand Miss. mid; Qu.J. Geol. S. xxxviii.

69.

SYSTEPHA'NIA, Ehr. —A genus of
Diatomaceae.

Char. Frustules circular ; valves alike,
areolar, neither radiate nor septate, with a
crown of spines or an erect membrane on
the outer surface of each valve (not on the
margin). Foss^il.

S. corona (PI. 18. fig. 57) ; 'S'. diadema
(fig. 58).

One other species ; found in Bermuda.

BiBL. Ehr. Ber. Brl. Ak. 1844, 264;
Kiitz. Sp. Alq. 126 ; I'ritchard, Infus. 832.

SYZYGITES, Ehrenbercr (see Phyco-
MYCES). — A genus of Mucorini (Phycomy-
cetous Fungi), containing two species, a
kind of mould growing over decaying
Agarics, remarkable among all the class to
which they belong for the occurrence of the

phenomenon of conjugation of the branches
as a preliminary to the formation of tho
spores. Ehrenbtsrg discovered the conju-
gation in *S'. megalocarpus many years ago.
The young filaments are simple, slender,
rather rigid, pellucid and straight, — soon
becoming forked, thickish, wliitish yellow
(somewhat olive when dry). The rudi-
ments of the peridioles spring out as papillas
from the branches, becoming pear-shaped ;
and when two come into contact, they coliere,
and become confluent into a fusiform body.
The contents of the filaments next ascend
and accumulate in the peridiole, at length
forming a black globule (sporange?). While
this is ripening, the apices grow out into
long simple filaments.

Fig. 716.

Syzygites megalocarpus.

A branched filament, exhibiting the conjugation in
various stages.

Magnified 200 diameters.

BiBL. Ehrenb. Verhandl. Naturf. Freund.
Berlin, i. p. 91 ; Fries, Syst. Mtjc. iii. p. 329 ;
Berkeley, Ann. Nat. Hist. i. p. 259; Van
Tiegh. Ann. d. Sci. Nat. 1873.

T.

TABELLARIA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules tabular, attached, at first
united into a filament, subsequently cohe-
ring only by the angles, with longitudinal
vittae interrupted in the middle ; valves
inflated in the middle and at each end,
striated ; freshwater.

T. focculosa (PI. 17. fig. 27 a, h). Septa
3-5 on each margin. Length 1-960 to
1-840".

T. fenestrata. Frustules oblong ; vittae
two, opposite. Length 1-600 to 1-290",

TACHIDIUS.

[ 750 ]

T^NIA.

Five fossil species.

BrBL. Kiitz. <S/j. AUj. 118 ; Smith, Br.
Dial. ii. 44 ; Pritcliard, Infus. 807.

TACinD'IUS, LiUj.— A genus of Cope-
podous Entomostraca. T. brevicornis ; ma-
rine. (Brady, Copep. ii. 10.)

TACHYGO'NIUM, Nag.— A doubtful
genus of Palmellacete. (llabeuh, Alg. iii.
36.)

TADPOLE. See Fbog.

T^EisIA (Tape-worm). — A genus of Ces-
toid Entozoa.

Char. Body elongate, compressed, jointed.
Head mostly broader than the very narrow-
neck, with four suctorial depressions ; and
usually a median, imperforate retractile
rostellum, very frequently armed with one
or two circles of minute recurved hooks,
especially in the young state. Genital ori-
fices situated at the margins of the joints or
proglottides, either on one side only, or on
both margins and on alterna,te j oints.

The Tcejiiee, of which the common tape-
worm may be taken as the type, are found
in vertebrate animals alone, and in these
only in the alimentary canal. They are
most common in birds, next in mammalia,
then in fishes, and lastly in reptiles.

The species are very numerous : Rudolphi
enumerated 14G; Dujardin 1.35.

Tcenia solium,the common human English
species, varies in breadth from 1-50 to 1-40"
at the anterior part, to about 1-3" at the
middle and posterior part. At the anterior
extremity is situated a central rostellum,
which is surrounded by a crown of small
recurved hooks, as in PI. 21. figs. 1 /& 10,
Behind these are four siictorial depressions,
which are not pervious at the bottom. The
digestive system is wanting, and the worm
absorbs by its surface; but according to
Blanchard, it is represented by two tubes or
lateral canals (PL 21. fig. 14 «), having be-
tween them a transverse canal at the sum-
mit of each joint; these extend from the
anterior to the posterior end of the body.
In the cephalic portion, directly behind the
suckers, there is a kind of lacuna or furrow
communicating directly with these intesti-
nal tubes ; and it appears that the nutritive
matters respired by means of the suckers
penetrate into this lacuna, and thence into
the digestive canals. These tubes have di-
stinct walls, and are best seen when the animal
has been macerated in water, and is exami-
ned by transmitted light, or after having
been injected. But this is very doubtful.

The vascular system, according to the

above author, consists of four longitudinal
vessels (PL 21. fig. 14 h) .-ituated'^ a little
above the intestinal tubes, and infinitely
more slender. They traverse the whole
length of the body; and between them
are numerous transverse vessels (PL 21.
fig. 14). These so-called digestive and vas-
cular canals are now considered as belonging
to a water-vessel system ; the canals unite
in the last segment in a receptacle.

The male generative organ consists of a
slender coiled tube, extending to near the
principal ovigerous canal, where it is pre-
ceded by some very small testicular capsules
(PI. 21."'fig. 14 c). - The slender tube termi-
nates in a duct (fig. 14 d), which opens into
the lateral orifice, or sometimes it projects
externally in the form of a spiculum. The
ovary consists of a principal median canal,
presenting slight flexuosities, and extending
nearly from one end to the other of each
joint. It presents ctecal branches on both
sides, and opens by a slender oviduct (fig.
14 e) just within the genital orifice.

The ova are innumerable ; one is figured
in PL 21. fig. 15. They consist of an outer
delicate membrane, enclosing a gelatiumis
substance containing numerous highly re-
fractive globules. Within this is another
very delicate and transparent membrane,
closely applied upon a brittle, dark-looking
(by transmitted light, but white by reflected
light), thick envelope, within which is the
yoUi or embryo, according to the state of
development of the ovum. Very frequently
the hooks of the young tajnia are seen im-
bedded in its centre, as shown in the figure.
The thick biittle coat of the ovum exhibits
an appearance of radiating fibres (canals ?) ;
and when broken, the fractures are radiant.
When the middle of the outer surface of
the brittle envelope is brought into focus, it
presents a tolerabty regular appearance, as
if composed of cells ; this arises, however,
from the extremities of the fibres being
broug-ht into focus.

The filiform spermatozoa are readily found,
simply by picking any joint containing ova
to pieces with needles.

The young animal, consisting of head and
neck only, was formerly considered distinct,
aud placed in a genus (Scolex).

Among other species may be mentioned :
Tcenia mediocanellata, the unarmed tape-
worm of the ox ; T. crassicollis, in the cat ;
T. echinococcnx, in the dog and wolf; 7'.
serrula, in the dog ; aud T. nana, human, in

T.ENITIS.

[ 751 ]

, TAEGIONIA.

The old genera Cccnwus, Cysticercus, and
Eclitnococcus are the larval or nurse-forms
of Tcenia.

BiBL. Weinland, on Tape-2vorms ; Som-
mer, Geschlechtsorg. v. T. sol. 4' mediocancl-
lata ; Megnin, Compt. rend. 1870, 8S, Ann.
N. IT. 1879, iii. 317; Piutiier, Ban S)-c.
1880; Aloniez, Cestodes, 1881; Stein, ^«^-
tcick. u. Parasitism, mensc/d. Cestoden, 1882.

T.ENITIS,Sw.— A genus of Grammitideie
( Pol vpodiaceous Ferns). Five species; tro-
pical. (Hooker, St/n. 300.)

TALC. See Mica.

TAO'NIA, J. Ag.— A genus of Dictyo-
taceas (Algse), containing one rare British
species, T. atomaria, which has a tiat, mem-
branous, fan-shaped, deeply cleft frond,
3 to 12" high, of brownish olive colour;
marked on both faces, at intervals of 1-4 to
1-2", with concentric wavy lines, formed by
rather crowded dark-brown " spores," the
interspaces being dotted over with scattered
spores. The disk of attachment is covered
with woolly hlaments.

BiBL. Harvey, Mar. Aly. 38; Thuret,
Ann. Sc. N. 4. iii. 7.

TAPHRl'NA.— A very low form of As-
comycetous Fuugi, formerly included under
EbikeUjVI, to which genus E. auremn, on
Poplar, and E. clandestijium, on Hawthorn,
are now referable. (Tulasne, Ajin. d. Sc.
K. ser. v. ; Greville, Crypt. Fl.)

TAPHROCAM'PA, Gosse.— A genus of
Rotatoria, of the family Hydatinsea.

Char. Kotatoiy organs absent; body fusi-
form, annulose, tail forked, gizzard oval.

T.annulosa. Freshwater; length 1-110",

BiBL. Gosse, Ann. N. H. 1851, viii. 100;
Pritchard, Inf. 602.

TAPIOCA. — A very purefecula prepared
from the finer particles of the starch of the
Mandioc or Cassava plant (PI. 46. fig. 14).
The starch-gi'anules of tapioca of the shops
appear to have imdergone the action of
heat, which disguises the characters. See
Staech.

TAPtDIG'EADA (Water-bears).— An
Order of Arachuida.

These microscopic animals are found in
stagnant fresh water, amongst water-plants,
in patches of wet moss, in the gutters of
houses, &c.

Body soft, cylindrical or elongate-oval in
outline, with four ti-ansverse furrows or in-
distinct segments, and a fifth anterior, cor-
responding to a head, short, conical, retrac-
tile and with indications of two or three
segments ; sometimes dilated at the end to

form a sucker, or furnished with unequal,
short, palp-like ])rocesses. Eyes two.

The oral organs are represented by a tu-
buliu" rostrum, through the sides of which,
from witliout inwards, two calcareous styles
or mandibles pass, and serve to wound the
animals forming their prey. At the base
of the rostrum is a gizzard with radiating
muscidar fibres, iu Macrohiotus enclosing a
kind of framework consisting of six parallel
jointed cyhuders.

The alimentary canal is straight, and fur-
nished with lateral cfecal appendages. The
ovary is a simple sac, behind which is
situated a seminal vesicle containing sper-
matozoa, both opening into a cloaca. But
few eggs are produced at a time ; they are
either smooth, rugose, or studded with
points, and are usually deposited during the
ecdysis, the exuviiB serving as a protection
to them during the process of hatching.
The young resemble the parents.

The Tardigrada resemble some of the
Rotatoria in reviving after having been kept
dried for years.

Genera : Emydium, Maa'ohiotiis, Milne-
sium {Arctiscon^ doubtful).

BiBL. Doyere, Ann. Sc. Nat. 2. xiv. 2G9,
xvii. 193, xviii. 1; Bujardin, x. 185; Vogt,
Zool. Briefe, i. 496 ; Kauftmann, Sieb. und
Koll. Zeitschr. iii. 220 ; Greef, Schidtze's
Archiv, i. 101; huhhock, Met am. of Insects.

TAPtGIO'NIA, Mich.— A genus of Pel-
liese (Hepaticse), characterized by the almost
sessile globose capsule arising from the end
of the midrib of the under face of the frond,
which is somewhat fleshy, smooth, deep-
green, piu'plish at the edges', and forms large
patches on rather moist but exposed banks.
The frond has an epidermis on both faces,
with stomata and intermediate parenchyma ;
the midrib is only apparent beneath, and
has radical hairs, with purple scales. The
perichjete originates from this rib, on the
under smface, rising to the upper side (fig.
717). "When mature, it is globose, of dark
purplish colour and firm texture, and marked
with a vertical prominent line or keel : at
this line it ultimately splits into two valves
(fig. 718). Hofmeister's observations, how-
ever, show that this envelope grows up
after the fertilization of the archegone,
which is originally naked in its upper half ;
hence it would seem to be a pcriyonc.
Several archegones are found half-immersed
in the end of the midrib ; and one of these
is converted into a fruit ; the lower part be-
comes spherical, and the neck forms for a

TAEGIONIA.

[ 752 ]

TEA.

Fig. 717.

Fi<?. 718.

Fig. 719.

Fig. 720.

Targionia hypophylla.

Fig. 717. Lobe of a frond with fruit. Magnified 5
diameters.

Pig. 718. Perichsete opened, showing the globular
sporange. Magnified 20 diameters.

Fig. 719. Vertical section of a very young sporange.
Magnified 200 diameters.

Fig. 720. A branched elater. Magnified 200 diameters.

Fig. 721.

Fig. 722.

Fig. 72.3.

Fig. 724.

Fig. 725.

■•%>-

Pigs. 721 & 722. Groups of four spores, not quite ma-
ture. Magnified 400 diameters.

Fig. 72:). Parent cells of spores and imperfect elaters,
from a more advanced fruit. Magnified 100 diameters.

Fig. 724. The same. Magnified 200 diameters.

Pig. 72-5. A single ripe spore. Magnified 400 dia-
meters.

loug time a filiform point or stj^Ie. This
epigone bursts irregularly and vertically.
The spherical capsule emerges from it, but
is not protrnded beyond the perichaste. The
globular capsule bursts irregularly at the
summit, and discharges spores and elatera
resembling those of Mca-chantia (figs. 723
to 725). The autheridia are imbedded in the
midrib, opening on papilhe on the lower face.

BiBL. Hook. Brit. Flor. ii. pt. 2. p. 105 ;
Corda, Sturiiis Deutschl. Fl. Jungertn. pi.
2G ; Nees, Lehernioose, iv,

TARTARIC ACID.— The crystals of
this substance, which belong to the obhque-
prismatic system, exhibit beautiful colours
under the polariscope. A concentrated
aqueous solution is useful in the chloride-
of-gold staining process.

TAYLO'RIA, Hk.— A genus of Splach-
naceiB (Acrocarpous Mosses). T. serrata
(fig. 474, p. 512), on Scotch mountains.
(Wilson, Bry. Brit. 28: J.)

TAX US, L. — Tax us haccata is the Yew
tree, belonging to the Coniferae. Its wood
(PI. 48. fig. 4), as also that of T. canadensis,
shows the remarkable combination of spiral
fibres with the coniferous pits. Its embryo-
logy is also interesting. See Conifee^
and Ovule.

TEA (the prepared leaves of Thea viridis
and 2\ BoJwa, Nat. Ord. Ternstrcemiacea3).
— This important article of commerce has
aftbrded some of the most remarkable ex-
amples of systematic i'raud, practised not
merely by the vendors in this country,
but by the Chinese manufacturers. The
principal adulterations of tea consist of re-
manufactured exhausted tea-leaves, spurious
tea made up of the dust of tea and other
leaves, together with earthy matter, by the
aid of gum, and of spurious tea made of
leaves of other plants, — the whole of these
being prepared either for black or green tea
by * facing,' or imparting a colour or bloom
with black-lead, indigo, prussian blue, mica,
turmeric, &c.

The leaves of tea may be distinguished
when moistened and spread out, and still
more decidedly, even in fragments, by the
aid of the microscope, which shows the
peculiarities of the epidermis of the upper
or lower faces, &c. (1*1. 2. fig. 1). Other
leaves fraudulently introduced may be tluis
separated, and often identified by careful
comparison with known lands likely to
have been employed. The spurious tea
made up of agulutinated rubbish falls to
pieces instead of unrolling when infused

TEETH.

[ '^->^' ]

TEETH.

with hot water. Tho 'facing' of the various
kinds is mostly distinguishable with a com-
mon lens, and when tlie tea is infused forms
a sediment, the characters of which may be
determined by tho microscope and by che-
mical analysis.

BiBL. liassall, J(w7i^-c.,L'G8; Warington,
Tr. Chem. Soc. 1851.

TEETH.— The teeth of the Mammalia
are inserted in sockets or alveolar cavities
of the jaws.

The teeth consist of : — a crown, or that
portion which projects beyond the alveolar
cavity and the gum ; the things, or the por-
tions which are inserted into the bony
structures ; and a neck, or narrower inter-
mediate portion. The crown of the tooth
contains the pulp-cavity, which is closed
above, but prolonged laelow through the
fangs.

In regard to their structure, teeth are in
part identical with bone, in part closely
allied to it ; but in respect to their develop-
ment, they must be regarded as formations of
the mucous membrane, as modified papillae.

The substance of human teeth consists of
three parts : — the ivory or dentine (fig. 726 d),

Fig. 726.

Molar tooth, human :

longitudinal section,
ivory,

with

a, enamel ; 6, pulp-cavity ; c, cement ; d,
the ivory -tubes. Magnified 5 diameters.

which constitutes the greater portion of
their mass, and to which their form is

mainly owing ; the cement, or bony portion
(tig. 726 c), which forms an external cov(>r-
ing, principally of the fangs ; and tho ena-
mel (fig. 726 a), which covers the crown.

The ivon/ or denfitic (figs. 726 d, 727 d) is
whitish and of a silky lustre, and, excepting
a small portion at the base of the fangs,
forms the entire boundary of the cavity of
the teeth. It consists of a homogeneous

Transverse section of the same; the references as above.
Magnified 5 diameters.

matrix enveloping numerous tubes or cana-
liculi, called the ivory-tubes (tig. 729 a, b).
The tubes are very fine, and pursue an un-
dulating course, at first curving, then bifur-
cating, throughout gix-ing off" numerous fine
lateral communicating branches, which are
best seen in a horizontal section (fig. 728),
and ultimately ramifying and anastomosing
freely. They commence at the surface of
the pulp-cavity, in the crown following a
somewhat radiating direction from its centre
(fig. 726), whilst in the fangs their course
is more horizontal. They have distinct

Fig. 728.

Transverse section of the ivory-tubes of the fang (a),
fig. 729), showing their numerous anastomoses.
Magnified 450 diameters.

walls, about equal in thickness to their
calibre, although in transverse sections (fig.
730) this thickness is generally exaggerated,
on account of their being obliquely divided.
They contain air in the dry state, which

3c

TEETH.

[ 754 ]

TEETH.

may be displaced by liquids. By reniuving
the inorganic salts iVom a tooth with dilute

Fig. 729.

Tvory-tulies of a fang of a human tooth, or, inner
surface of the ivory, witli fiw tubes ; h, their branches ;
c, their terminations in loops ; d, granular layer, con-
sisting of small ivory globules at the boundary of the
ivory; e, lacunie of bone, one anastomosing with an
ivory-tube. Mognilled 50 diameters.

muriatic acid, and macerating the remaining
cartilage with acids or caustic alkalies until
it forms a pasty mass, the tubes may be
isolated from the basis.

Fig. 730.

< ® ® .^ ®*^ I
\s ® ® ®/

Transverse section of the ivory-tubea. a, closely
aggregated; 6, wider apart. Magnified 4-50 diameters.

In sections made from fresh teeth, high
powers of the microscope (-500 or 1000
diameters) being used, it is not difficult to
recognize, especially in the centre of the

Fig. 731.

Perpendicular section of the apex of a human incisor
tooth. «, pulp-cavity ; 6, ivory ; c, curve'd contour lines
with interglobular spaces; (/.cement; c, enamel, with
indications of the course of the tiliris in various direc-
tions ; y, coloured stripes of i he enamel.

Magnified 7 diameters.

TEETH.

[ 755 ]

TEETH.

tooth, the fine, pale, homogeneous processes
of the totith-pulp or deiiliue-fibres. These
may be stained by carmine.

"the ivory not unfrequently exhibits indi-
cations of a laminated structure, forming-,

Eig. 782.

Portion of tlie ivory, with ivory-globules and inter-
globular spaces filled with air. Muguified 350 diams.

in longitudinal sections, curved lines more
or less parallel to the outline of the crown
(fig. 731), appi\aring as rings in transverse
sections, and called the contour-lines.

Fig. 733.

Cement and ivory of the fang of a tooth of an old
person, a, cavity; b, ivory; c, cement with lacunse ;
e. Haversian canals. Magnified oO diameters.

Near the enamel (fig. 731) and the cement
(fig. 7:29 d) also, the ivory presents one or
more irregular dark patches or bands, often
continuous -with the ends of the contour-

lines, and exhibiting a coarsely cellular
appearance. On careful examination, the
d.irk appearance is seen to result from a
number of irregular spaces filled with air
(fig. 732 a) iiitevveniiig between certain
globules, called ivory-<jlohules, the spaces
being termed the interf/hhular sjMces. In
the recent tooth, these spaces are filled with
the organic basis of the ivory, containing
tubes likethe rest of that substance, in which,
however, the inorganic matter has not been
deposited ; hence this structure arises from
imperfect development.

Other, ill-defined iridescent stripes, run-
ning parallel to the pulp-cavity, are some-
times seen ; these correspond to the primary
curves of the ivory-tubes.

The cement or bone of teeth forms the
outer coating of the fangs (figs. 726 & 733, c),

Fig. 734.

Enamel-fibres, isolated by the very slight action of
muriatic acid ; human. Magnified 130 diameters.

sometimes cementing them together. It
commences as a very thin layer at the part
where the enamel ceases, increasing in
thickness towards the ends of the fangs.
The cement does not differ from bone in
structure, except in rarely containing Ha-
versian canals. In the molar teeth of old
persons, however, these are met with
(fig. 733 e). The lacunae are frequently
absent from the "thinner portion of the ce-
ment ; and it sometimes contains tubes like
those of the ivory. The interlacunar sub-
stance is sometimes striated, and exhibits a
laminated structure.

The enamel (fig. 72G a) covers the ivory

3c2

TEETH.

[ 756 ]

TEETH.

of the ciown of the teeth. It is thickest at '
the opposing surface, decreasing towards
the neck, where it terminates. The cuticula
is an extremely resistant investment to the
exposed portions of the teeth, and wliich
disappears when they are mature. It is
separable after the action of muriatic acid,
and may be tinted with a solution of nitrate
of silver, which causes the appearance of
figures like large epithelial cells. The
enamel has a fibrous aspect, and appears of
a bluish-white colour by reflected light,
and of a greyish browu by transmitted

Fig. 735.

light. It is very brittle, and so hard as to
strike fire with steel. It consists of nume-
rous solid fibres or prisms (fig. 734), about
l-()000 to 1-5000" m breadth, mostly six-
sided, more or less wavy, slightly varicose,
and transversely striped. These usually
extend throughout the thickness of the
enamel, and are placed in a direction gene-
rally perpendicular to the surfiice of the
portions of the ivory which they cover
(figs. 726, 731). The form of the 'fibres is
best seen by viewing their ends in a trans-
verse section (fig. 735). The prisms do not

Fig. 736.

^-iSs,

Fig. 735. Sc.rface of the enamel, with the ends of the enamel-fibres, from the tooth of a calf. Magnified 350
diameters.

Fig. 736. Diagram showing the develojiment of a milk-tooth, and the corresponding permanent tooth, a, furrow ;
6, the same with the papilla ; c, the same closing, with the commencement of the reserve cavity ; d, the same, further
closing; e, follicle completely formed, with the reserve cavity; y, the reserve cavity receding; g, the same, with a
tooth-germ ; h, the alveoli of both capsules formed, the milk-tooth being through the gum ; i, the same further
advanced, the neck of the capsule forming a solid cord.

run exactly parallel with each other, but
are arranged in groups or zones, the fibres
of which cross each other. The fibres
are readily isolated before they have be-
come so developed as to be hard, and when
very slightly acted upon by muriatic acid.
It is doublfid if sometimes the ivory-tubes
extend into the enamel.

Two kinds of dark bands or stripes are
seen traversing the enamel (fig. 731). The
direction of one of these coincides pretty
nearly with that of the fibres, and it arises
from the crossing of the zones of fibres,
allowing more or less light to pass through,
the bauds being light and dark. The other
set (fig. 73l,ff) consists of arched, brownish
stripes, indicating the laminated structure

of the enamel. Under the polariscope, a
third set becomes visible, arising from the
variable inclination of the axes of the fibres
to the plane of polarization.

The en.imel is often traversed by cracks,
mostly running parallel with the fibres, and
containing air in dry teeth.

Pulp. — The pulp of the teeth is the vas-
cular and nervous matrix of the dentine
and the remains of the original tooth-papilla.
It contains a few blood-vessels and nerves,
being connected with the periosteum and
base of the sockets of the jaw. The princi-
pal part is made of indistinctly fibrous con-
nective tissue, containing numerous cells;
and it appears to be quite cavernous from
the breaking up of the terminal capillaries.

TEETIT.

[

I ■)!

]

teJ':tii.

The external layer is formed of Lirge cells of
elongated form, provided witli immeroiis
processes culled odontoblasts, which are
ai-ranged so as to form a kind of colunmar
epithelium. They are tinely granular, but
have no cell-wall. Three kinds of pro-
cesses may be distinguished in these cells —
the dentinal, pulp, and lateral processes.
The dentinal processes become the before-
mentioned dentinal fibres of the ivory.

Chemically, teeth consist of an organic,
cartilaginous basis, agreeing iu composition
with that of bone, and of inorganic matter,
consisting principally of phosphate of lime
with a sni ill quantity of the carbonate.

JJiVii/ojjment. — At tho beginning of the
third mouth, the margins of the jaw form a
slight ridge, which consists of a thickening
of the embiyunic connective tissue and
epithelium of the mucous membrane of the
mouth. The rudiments or germs of the first
(milk) teeth are met with in the sixth week
of fcetal life, ar.d consist of small papillae,
one for each tooth, which become visible iu
grooves of the mouth, afterwards forming

Fig. 737.

Lower jaw of a human nine weeks' foetus, a, tongue,
turned back ; 6, right half of the lower lip turned aside ;
ft', left half of the lip cut off: c, outer wall of the gum;
d, inner wall of the gum; e,f,g. *, papilla; of the teeth;
•, fold where the sublingual duct subsequently opens.

Magnified 9 diameters.

the alveolar processes. The epithelium
forms the enamel, and the other tissue the
dentine and cement. Processes from the
sides of these dental grooves are then
formed, and, approaching each other, en-
close the papillte iu distinct follicles, the
margins of which gradually grow over the
papillse, and uniting, convert them into

closed sacs or capsules. The pulps then be-
conu! moulded into the form of the future
teeth, the bases of the pulps dividing into
as many portions as the teeth have fangs ;
and as tho capsules increase at this stage
faster than the pulps, a space is left be-
tween them, in which a gelatinous-looking
substance is deposited from the wall of the
capsule forming the enamel-organ. By
some recent authors, however, the existence
of the dental grooves is denied.

Tlie capsule (fig. 738 a) possesses a con-
nective coat with vessels and nerves ; and
from its base arises the tooth-germ or pulp
(fig. 738 h). The pulp consists of an outer

Fig. 738.

Capsule of the second incisor tooth of an eight months'
human foetus, a, capsule; 6, enamel-pulp ; c, enamel-
membrane; d, enamel; f, ivory-cells; h, papilla of
tooth or pulp; i, free margin of enamel-organ.

Magnified 30 diameters.

non-vascular layer of elongated nucleated
cells, with filiform processes, in close appo-
sition (fig. 739 rt), covering the surface of
the pulp — the ivory-membrane (fig. 738y),
not distinctly defined internally, but gradu-
ally passing into the vascular parenchyma
of the pulp. Tlie inner part of the pulp
consists of indistinctly fibrous connective
tissue -^ith nuclei, tlie vessels terminating
in loops beneath the enamel-membrane
(fig. 739 c).

The enamel-organ (fig. 738 h) covers by
its inner concave surface the pulp, its out-

TEETH.

[ 758 ]

TEGEOCRANUS.

side being in apposition witli tlie capsule.
It forms a spongy tissue, composed of ana-
stomosing stellate cells or reticular areolar
tissue; in its inside is the enamel-mem-
brane, consisting of c^lindrical epithelium
(fig. 738 c).

The enamel is formed by the direct cal-

Fig. 739.

Surface of the pulp of a newly-born infant, a, ivory-
cells; 6, their inipendagfs ; (■, vascular part of the pulp.

Magnified .300 diameters.

cification of the epithelium, the prisms re-
sulting from the calcification of the long
cylindrical cells.

" Ossification commences by the deposition
ofcalcareous matter in the cells of tlieivory-
membrnne at the summit of the pulp ; this
is soon folloAved by similar deposition in the
cells of the enamel-membrane. By the fur-
ther formation of new cells and fresh depo-
sition, the structure of the teeth becomes
more and more consolidated, the spongy
tissue of the enamel graduallj' being ab-
sorbed.

When the entii'e enamel and a consider-
able portion of the ivory have been formed
in the capsules, these become too small to
contain the teeth, which tlien rupture them,
and continue to grow at the root, until the
crown projects above the margin of the jaw.
The remainder of the capsule then forms
the periosteum of the alveoli, and, by depo-
sition from the side next the tooth, pro-
duces the cement.

The permanent teeth are formed upon
the same plan :■ — the three last molars in
the remains of the primitive dental groove;
tlie others in distinct sacs, called reserve

sacs, and formed in the wall of the follicles
of the milk-teeth.

The teeth of animals present numerous
interesting varieties, to which we can but
briefly refer. Thus, in the Mammalia the
enamel is often absent, the cement fre-
quently extends over the crown, the three
component structures are folded, the teeth
are compound, the ivory contains Haver-
sian canals, and the ivory-tubes enter the
enamel. In Eeptiles the teeth are often an-
chylosed to the jaws. In Fishes the teeth
are often solid ; the ivory is furnished with
Haversian canals, sometimes isolated, and
each surrounded by a layer of ivory and ce-
ment, so that the teeth appear to consist of
aggregations of little teeth ; the vessels
often branch and anastomose freely ; the
ivory-tubes are often very large or absent,
the ivory then consisting of a finely granu-
lar base with numerous vascular canals, true
enamel appe.aring to be absent.

The oral and gastric teeth of the Mol-
lusca (see Tongue), Vermes, and Arthro-
poda, are composed of chitine, which is some-
times impregnated with lime or silica. The
teeth of Echinida are composed essentially
of thin leaflets aggregated into a radial
lamina ; and they are composed of elongated
prisms of carbonate of lime, somewhat
curved at their extremities. These lustrous
calcareous plates lie between the prisms, and
present a fine plexus of anastomosing cana-
liculi.

It may he said generally that the teeth
of the higher Invertebrata are to be re-
garded as epithelial structures, and that in
the lowest Yertebrata they are chiefly com-
posed of peculiarly modified and ossified
connective tissue.

The method of maMug sections of teeth
is described under Peepakation. They
should be very thin, and preserved in the
dry state.

BiBL. Owen, Oclontot/raphi/, and Todd^s
Cyd. iv. 864; Goodsir, Ed. Med. and Svn/. Jii.
1839, i. ; Tomes, Dental Surgcn/, and Phd.
Tr. 1849, 1850; Hanover, Verh. Leopold.
Carol. Ak. xxv. 2, Mic. Jn. 18.'57, v. 166;
Huxley, Qu. Mic. Jn. 1854, 18.>5, 1857;
Lankester, Qu. Mic. Jn. 1867 ; Boll, Zahn-
jndpa, Arch. Mih. An. iv. 1868 ; Cutler, Den-
tal Comos, 1867; EoUeston, Qu. Mic. Jn.
1872; Waldeyer, StricJicr's Hum. c^- Comp,
Hist. i. ; Wliite, Mn. Mic. Jn. vii. 2(;3 ;
Tomes, M. M. Jn. xiii. 85 ; Frey, Hist, and
the lit:

TEGEOC'RANUS, Mich.— A new genus

TELOTKOCIIIDIUM.

[

]

TEST-OBJECTS.

of Oribatea (Michael, Jn. Mk: Soc. 1879,
247; 1S80, .'^2. 177).

TELOTROCIIIDIUM, Kt.— A gomis of
Peritiichoiis Iiifu.'^oria. Free, ovate or cam-
pannlate, no tail ; two ciliary rings ; anal
aperture iiosterior.

T. craterifunne ; freshwater. (Kent, Inf.
643.)

TEM'ORA, Baird.— A genus of Copepo-
dous Eutoinostraca, family l)iaptoniid<ie.

Char. Thorax composed of fiye, abdomen
of three joints; lesser antenute two-branched ;
first four pairs of legs each giving otfa two-
jointed branch. T. finmarchica. On the
British coasts. (Baird, Br. Entomostr. 227 ;
Brady, Cop. i. 37.)

TFA^DON. See Ligaments.

TEXTHRE'DO, Leach.— A genus of Hy-
menopterous Insects, of the family Tenthre-
dinidae (Saw-flies).

The species of Tenthredo and of the other
genera belonging to the family, both of
which are very numerous, are interesting on
account of the remarkable structure of the
ovipositor, which consists of two flattened
and curved saw-like plates. These are used
to saw the leaves of plants, for the deposi-
tion of the eggs.

The insects are found upon gooseberry-
bushes, rose-bushes, the white thorn, the
willow, alder, poplar, the plum- and other
fruit-trees, cabbage, turnip, bramble, &c.
The larvse ai'e very destructive to agricul-
tural crops.

T. nassdta is represented in figure 866
(p. 437).

BiBL. Westwood, Introductinn., ii. 90.

TEREBEL'LA.— A genus of Tubicolar
Annulata.

The animal forms a tube of sand and por-
tions of shell, agglutinated by a secretion.
Carpenter remarks that in the respiratoiy
organs situated in the part outside the tube
— the head — two liquids may be seen circu-
lating:— one colourless, containing numerous
cell-like corpuscles, which can be seen in
the smaller and more transparent species to
occupy the space intervening between the
outer sm-face of the alimentary canal and
the inner wall of the body, and to pass
from this into canals, which often ramify
extensively in the respiratory organs, but
are never furnished with a returning series
of passages ; while the second is a usually
red liquid containing few particles, and en-
closed in a system of proper vessels commu-
nicating with a central propelling organ. In
Terehella a distinct provision is made for the

aeration of both fluids ; for the first is trans-
mitted to the tendril-like tentacula which
surround the mouth, whilst the second cir-
culates through tlie beautiful arborescent
branchine situated just behind the head.
The ibrmer are covered with cilia, the action
of which continually renews the water in
contact with them, whiLst the latter are
destitute of them. The colourless liquid
is probably blood, and the red belongs to the
water-system.

BiBL. Huxley, Comp. An. ; Carpenter,
Micro.scope.

TERPSIN'OE, Ehr.— A genus of Diato-
macese.

Char. Frustules tabular, obsoletely
stalked, subsequently connected by isthmi,
and with transverse, short, interrupted,
capitate vittaj ; valves in side view with
lateral inflations.

T. musica (PL 19. fig. 33, side view; PI. 2o.
fig. 10, front view). Frustules very faintly
punctate, in front view rectangular oblong;
side view equally inflated in the middle and
at the ends, in older specimens constricted
in the middle, inflated beyond the middle
towards both ends, the apices produced and
obtuse, the nodules separated by septa.
Length 1-180".

T. indica (Anatdus ind., E.).

BiBL. Ehr. Ahh. Berl Ak. 1841, 402;
Kiitz. Bacill 128 ; Sp. Ahj. 119; Pritchard,
Inf. 850.

"TESSEL'LA, Ehr.— A genus of Diato-
macese.

Char. Frustules broadly tabular, not con-
catenate, with crowded, longitudinal, alter-
nate vittfB, interrupted in the middle; stipes
absent (?). Marine.

T. interrupta (PI. 19. fig. 3o). Leno-th of
frustules 1-580; breadth 1-560 to 1-120".
Found with Striafella.

BiBL. Ehr. 7h/: 202 ; Kiitz. Bacill. 125;
Sp. Alff. 114; Pritchard, Inf. 804.

TESTAMGEBIFOR'MIA, Carter.— Pa-
rasitic, lobular, and wild-growing Forami-
nifera, some nearly i inch long. Huluclad-
nia and Cydt'odictynia with calcareous,
Ceratestina with chitinous test. Gulf of
Manaar. (H. C. Carter. Ann. N. H. June
1880, 446.)

TEST - OBJECTS. — Te.st-objects are
microscopic objects used to determine the
value of object-glasses.

We must presume that the reader has
perused the remarks upon object-glasses in
the Introdl'ction (p. xvi), al.so the article
Angular Aperti-re; otherwise the

TEST-OBJECTS.

[ reo ]

TEST-OBJECTS.

observations made here will be unintel-
ligible.

The main points in which object-glasses
diifer from each other are four : viz. their
magnifying power ; their defining power ;
their penetrating power ; and their correc-
t've adaptations.

The magnifying or separating power
scarcely requires notice ; it must be adapted
to the size of the objects likely to come
under examination. Usually, several object-
glasses are kept, of ditfereut powers ; at all
events, if scientific investigations are to be
pursued, a power of 400 diameters must be
accessible, and this without the use of the
highest eyepiece. The magnifying power
should be ascertained by Measurement,
and not by j udging from the focal length.

Giood defining power is the most im-
portant character of an object-glass ; and if
good in respect to this, the dark boundary
lines of the test-objects will appear clear,
black, sharp, as if engraved, and quite free
from colour. If this is ascertained to be
the case, the higher eyepieces should be
put on ; and it must be observed that
although the sharpness of the outline is
somewhat diminished, all the parts are
clearl}' distinguishable as before. In this
examination the light shoidd be as direct
as possible.

The power of displaying the minute or
internal structural peculiarities of objects,
or the penetrating power, as it is called, de-
pends upon two distinct circumstances — the
goodness of the defining power, and the
magnitude of the angular aperture of the
object-glass: the degree of obliquity of the
light is also of great importance in con-
nexion with the latter.

Thus, in examining the scale of a Podura
(PI. 1. fig. 12 ff, b,c), the magnifying power
being sufficiently high, if the defining power
be good, tlie wedge-shaped bodies will be
clearly and sharply displayed by direct light,
and whether the angular aperture be large
or small. But if we examine a valve of
Fkurosiffftia (Tl. 1. figs. 17 & 18) by direct
light, the minute structure will be invisible,
however small or large the angular aperture
may be, or however perfect the defining
power ; but if the light be thrown obliquely,
and the aperture be sufficient, the stri;i3 will
at once become evident. Thus there are
two distinct kinds of penetrating power,
one of which is the same as the defining
power, the other depending upon a difi'erent
cause ; hence the term penetration or pene-

trating power should be laid aside, as
tending to cause confusion, the properties
of object-glasses being reducible simply
to their defining power and their angular
aperture.

In recent times, a new meaning has been
assigned to the term penetrating power,
viz. that of rendering a certain thickness of
an object visible at one time. This de-
pends upon the smallness of the angle of
aperture of the object-glass. It seems a
useless innovation.

The defining power should be tested upon
the difi'erent objects mentioned below in
connexion with each object-glass, and the
angular aperture should be determined by
measurement (Angular Aperture) ; for
judgment founded upon the examination of
the valves of the Diatomacete may be very
fallacious to an unpractised observer, on
account of the influence of the obliquity of
the light, and of the correcting adjustment.
If, however, an opinion is to be formed in this
way, the valves should be examined by ob-
lique light thrown from all sides, as with
the central stop in the condenser, so that
the dots may be viewed ; fur an object-
glass may show the lines very fairly, but
the dots very badly.

The correcting adjustment is of import-
ance in examining very delicate objects or
structures with the high powers ; it should
therefore always be present.

We subjoin a list of a few of the objects
which will be foiuid most suitable for the
purpose of testing an object-glass.

I5 07' 'I-inch ohject-glass. Magnifying
power 20 diameters.

Test-objects : the pygidium of the flea
(PI. 1. fig. 13 a), in which the general out-
line and the hairs should be distinct; the
hair of the mouse (PI. 1. tig. 3). Also, as
an opaque object, a piece of an injected
preparation (PI. .39. figs. 33-35).

1-inch or ft-ds object-glass. Magnifying
power 60 diameters.

Tests: hair of Dcrmestes (PI. 1. fig 1);
of the bat (fig. 2) ; of the mouse (fig. 3) ;
the pygidium of the flea, the outline of the
areola being distinguishable under the high
eyepiece (120 to 200 diameters), but not
the rays. Also an injection, as a piece of
lung._

\-inch or -i^Jhs-inch ohject-glass. Magni-
fying power 100 to 120 diameters.

Tests : hairs (PI. 1. figs. 1, 2, 3) ; the disks
of deal (fig. 4) ; the coarser scales of Le-
pisma (fig. 6 a) ; the pygidium of the flea

TEST-OBJECTS,

[ 761 ]

TEST-OBJECTS.

(fig. 13 a, h), the entire structure visible
under the high eyepiece ; a dark scale of
iWjim {PI. 1. fig. 12 6).

\-inch oI)ject-ijlass. Magnifying power
220 diameters.

Tests : liair of Dermestes ; the disks of
deal; the salivary corpuscles (PI. 1. tig. 5),
the moviuo; molecules being clearly distin-
guishable ; tlie smaller scales of Li'pisma
(PI. 1. fig. 6 b, c) ; the scales of Pudura ;
the filaments oi Didi/mo/ielix (fig. 10 a) ; the
pygidium of the Hea, and the scales of
Fonfia brassicce (PI. Si. fig. 24).

Ifh-inch objed-glass. Magnifying power
420 to 450 diameters

Tests : the paler scales of Podura ; the
pygidium of the flea ; the scales of Pontia
brussicfs ; the filaments of Didymohelix,
showing the component fibres ; the salivary
corpuscles.

^\ih or ^\fh-inch object-glass. Magnify-
ing power GOO to (3o0 diameters.

Tests : the paler scales of Podura ; the fila-
ments of Didj/ino/i^lix mounted in balsam ;
and the primitive tibrillae of muscular fibre
(PI. 22. fig. .36 6, rf).

,';</* a?ul upioards. Magnifying power
1250 to 2000 diameters.

Tests : the more delicate of the above
obiects, and the finest Nobert's lines.

It wiU be observed that we have omitted
the tests for angular aperture, which are
often now regarded as the true tests of the
value of an object-glass. Those, however,
who wash for an interesting series of difficult
objects in this respect, may use that of
Dippel, viz. : the valves of Pleurosigma for-
mostim, attenuatum, anyulatum ; Grainmato-
2)1wra marina ; NitzscMa mjmoidea ; Navi-
cula rhomboides ; N. affinis, Amici's test-
object, that used at the Exhibition of 1802,
mounted in balsam, the transverse lines ;
Surirella gemma, the longitudinal lines;
Grammatophora subtilissima ; Frustulia
saxonica, and Bailey's Hyalodiscus subti-
liss{7nus. Nitzschiatcenia and Berkeleya fra-
gilis are also fine objects, MoUer's or
Rodig's Test-plates may also be used. These
consist of a series of the valves of Diatoma-
ceae, arranged according to their difficulty,
and moimted on a glass plate in balsam.
We shall now offer a few
General remarks on the application of
test-objects to the choice of an object-glass.
A gi-eat difficulty presents itself in this ques-
tion in the case of persons commencing the
use of the microscope ; for on viewing
almost any object, they will see so much

that was invisible before, that they are natu-
rally led to regard an object-glass as good
which may simply possess tolerably magni-
fying power.

There is also some difficulty to an un-
practised eye in discriminating between a
well-defined margin of an object, and one
which is ill-defined. This may be overcome
by purchasing one or two test-objects from
those who mount objects for sale, and first
viewing them under their microscopes; or
by examining some of the objects exhibited
at the evening, meetings of the learned
societies.

The objects themselves are also variable,
some being much more delicate than others
even of the same kind. Moreover objects
viewed under immersion-glasses are more
brilliant than under the dry object-glasses.
The manner in which objects are mounted
is also of importance; for if they be immersed
in too much balsam or covered by too thick
a cover, no object-glass will show them well,
however good it may be. Hence the ne-
cessity of purchasing the test-objects, in the
case of an inexperienced observer. Any of
these may be obtained from Norman, Foun-
tain Place, City Road; Wheeler, 48 T(j1-
lington Road, HoUoway ; Baker, 244 High
Holborn ; of Smith and Beck, Ross, or
Powell ; or Bourgoyne, of Paris,

A few notes upon the test-objects them-
selves may not be out of place here.

Hairs of animah (PI. 1. figs. 1-3). These
should be mounted in Canada balsam. Many
of those represented in PI. 29 might be used
with equal advantage.

Disks of deal (PI. 1. fig. 4), fonn a good
test-object on account of their freedom from
colour, whence the colours from uncor-
rected chromatic aberration are easily seen
with a bad object-glass.

Salivary globules (PI. 1. fig. 5 a, b, c). Ob-
tained from the saliva. A good test-object
for those engaged in physiological investi-
gations ; the marginal granules and the
moving molecules should be very distinct,

Scales of insects (PI. 1. figs. 6 «, b, c, 12 a,
b, c; PI. 34. fig. 24), These should be
mounted dry. The scales of Tinea and many
others have nothing to recommend them.
Nor do we advise the use of those scales
which exhibit the transverse stria? by oblique
light, as those oi Morpho (PI. 1. fig. 7), of
Hipparchia (fig. 9), Sec, as they are easy
tests even to inferior English object-glasses
of the present day. The long scales of
Pontia brassicce, however, are good.

TEST-OBJECTS.

[ 762 ]

TP]TRAXYCHUS.

DichmioheUx (PI. 1. fig. 10 a, h, c, d).
The fiiaments should be mounted in solution
of chloride of calcium, or in Canada balsam.
It is very difficult to display the component
fibres of this beautiful object when in bal-
sam. It also forms a good test of magni-
fying power.

Dich/moprium (PI. 1. fig. 11). The lon-
gitudinal lines upon the cells require con-
siderable magnifying power.

The pyi/idimn of Pulex. An excellent
test-object, mounted in as small a quantity
of balsam as possible. Dujardin represents
the rays upon the disks as round, like so
many beads, wliereas they are wedge-shaped
with the bases outwards.

The valves of the Diatoniacece. It is a
difficult matter to show the lines upon
Grammatophoramarinaw\t\\ an object-glass
of 110"^ of angular aperture, requiring ex-
tremely oblique light ; but many of those
mentioned above are far more difficidt.

The tdtimate JibrUUc of muscidar jihre
(PI. 22. fig. 36). Mounted in Hquid.
Kolliker represented them as beaded
(fig. 36 c) ; they have also been repre-
sented as in a : probably both these inac-
curacies arise from im^jerfect adjustment,
and from their immersion in too much
liquid. Their true structiu-e is figured in
h, d, e.

Foherfs test-lines. See ISTobert's lines.

We have omitted to notice several test-
objects, as the scales of some insects, a
minute globule of mercury, &c., because the
former have been so obscurely described
that we are unable to comprehend in what
the test-structure consists ; and the test-
appearances presented by the latter viewed
as an opaque object are inappreciable to one
unaccustomed to the use of the microscope,
by whom mainly are remarks upon test-
objects required. See on this matter,
Wenham, in Beale's How &c. p. 436.

Che^•alier's test-object consists of the
scales of Pontia hrassicce (PL 34. fig. 24),
the granules being rendered distinct ; this
is a test for definition.

Mohl recommended the scales of Hip-
2mrchia janira for testing penetrating-
power ; pollen-gTains, the scaly elytra of the
diamond-beetle, or bat's hair, for definition.

Schacht's test-object consists of the scales
of Hipparchia janira (PI. 1. fig. 9r), a test
for moderate angular aperture and oblique
light.

13iBL. That of the Inteoduction, and
of Angular aperture.

TE'THEA, Lam. — A genus of marine
Sponges.

Char, Solid and compact,rounded, covered
with a skin ; without sensible pores ; inte-
rior fleshy, with acicular and globulo-subu-
late sjDines (PI. 4.5. fig. e).

BiBL. Johnston, Br. Spong. !->l ; Gosse,
3Iar. Zool. i. ; Huxley, Ann. N. H. 1851,
vii. 370.

TETMEM'ORUS, Ralfs.— A genus of
Desmidiacese.

Char. Cells single, simple, elongated,
straight, cylindrical or fusiform, constricted
in the middle ; segments emarginate at the
ends.

Sporangia square or round.

T. (jranuMus (PI. 14. figs. 33, 34) . Cells
fusiform both in front and side view, ends
colourless and lip-like ; dots irregular.
Length 1-1.30".

T. leevis (PI. 14. fig. 35, in conjugation).
Cells in front view somewhat tapering, ends
truncate ; side view fusiform ; dots none, or
very indistinct (under ord. ilium.
1-350".

T. Brebissonii.

Length

Dots in longitudinal
rows.

BiBL. Ralfs, Br. Besmid. 145 ; Rabenht.
Alq. iii. 139.

TETRACHAS'TRUM= Mcrasf'^-ios pt.

TETRACTIN'lUM,Brn. = P(r/m.s!';7»» pt.

TETRACY'CLUS, Ralfs.— A genus of
Diatomacefe.

Char. Frustule? compound, aggi-egated
into a filament, in front view broadly tabular
with longitudinal interrupted vittae ; valves
inflated on each side in the middle.

Valves with coarse transverse strise.

T. Thienemamii, Ehr. (lacustris, Ralfs)
(PL 17. fig. 28). Valves rounded or sub-
acute at ends, inflations rounded.

T. cmarginatiis. As the last, but valves
constricted towards the rounded and sub-
apiculate ends, and the inflations emar-
ginate.

BiBL. Ralfs, Aym. N. H. 1843, xii. 105 ;
Kiitziug, Sp.Alg. 118; Smith, Br. Diat. ii.
37 ; Rabenht. Alg. i. .302.

TETRAGON'iCEPS,Brady.-A genus of
Copepodous Entomostraca. T. vwUcoIata,
in dredgings. (Bradv, Copep. ii. 65.)

TETRAM'ITUS,Perty.— A genus of Fla-
gellate Infusoria. Free, changeable, tapering
behind, truncate in front; flagella four.
Three species ; in stale water and infusions.
(Pertv, Lebensf 170 ; Kent, Inf. 313.)

TETRAN'YCHUS, Duf.-A genus of
Trombidina (Acarina). Spinning-mites.

TETRAl'EDIA.

[ rm ]

TEXTULARIA.

CJiar. Palpi incumbent upon the rostrum,
stout, short, and conical; mandibles and
labium as in liluiphuinatlius ; palpi chelate;
cox;b inserted in two groups on each side,
, one for the two anterior, the other for tjie
two posterior; anterior legs longest, third
^ joint (femur) largest ; claws short and
greatly cm-ved, and with rigid bulb-pointed
hairs.

Several species and varieties, red and
green.

T. telarius, the red spider. Yellowish ;
abdomen produced behind ; a dark yellow
spot on each side of the back. On ill-
conditioned greenhouse-plants, forming a
web.

T. fflaber (PL 6. fig. 32). Very minute ;
eyes two, whitish, upon the anterior pro-
minence. Under stones in damp places.

T. htpidum (cnsfotus, Duges) (PI. 6.
fig. 35). Legs slender, anterior very long ;
eves three on each side ; several rows of
white points upon the back and margins of
the bod}'. Under stones and upon plants.

Claparede places Tromhidium antiimuale
in this genus.

BiBL. Duges, Ann. Sc. N. 2. i. 24, & ii.
55 ; Gervais, Wo.lckenaeys Apteres, ii. 165 ;
Dufour, Ann. Sc. N. i. xxv. 279; Koch,
Dctitsc/il. Cnistac. ; Boisduval, £nt. Jlorf.
88 ; Murrav, ^c. Lnt. 97.

TETRAJPE'DIA, Reinsch.— A genus of
Unicellular Algfe.

Char. Cells compressed, quadrangular or
triangular, equilateral, becoming subdivided
into quadrate or connate segments or
rounded lobes, either by deep vertical or
oblique markings or by wide angular or
rounded sinuses. (Archer, Qu. Mic. Jn.
1872, 351.)

TETRAP'LOA, Berk, and Br.— A genus
of Tondacei (Coniomycetous Fungi), com-
prising at present a single species, T. aris-
tata, a curious little fungus growing upon
leaves of gi-ass. See Toeulacei.

TETRAP'LODON, Br. and Sch.— A ge-
nus of Splachnacefe (Acrocarpous operculate
Mosses). T. mnioides and angustatus, on
dung in moimtainous regions.

TETRASEL'MIS, Stein.— A genus of
Flagellate Infusoria. Free, obovate or
oblong; flagella four; protoplasm green,
with an eye-spot. T. cordiformis, fresh-
water. (Kent, Inf. 315.)

TETRAS'PORA, Link.— A gen us of Pal-
mellace8e(Confervoid Algte), nearly related
to the Ulvacese; indeed it is very difficult
to di-aw any very distinct line of demarcation

between Tetraapora and Monostroma, the
fronds of both of which are membi*anous
strata formed of a single layer of cells ; the
latter, however, has its constituent cells
crowded, while in Tetrnspora the green cell-
contents lie scattered, mostly in groups of
two or four, in the gelatinous frond. Thuret
states that the cells possess long cilia in the
stage when they are imbedded in a contin-
uous frond (PI. 7. fig. 10). Development
by the ciliated cell-contents breaking out as
swarming zoospores. Two recorded British
species appear to be distinct, growing in
stagnant pools.

T. gelatinosa (PL 7. fig. 10). Frond gela-
tinous, soft, of irregular shape and division,
pale green; cells 1-10800 to 1-4200" in
diameter (Kiitzing, Tab. Phyc. i. p. 28).

T. lubrica. Frond green, elongated, me-
sentery-shaped, lobed and sinuated, lobes
often anastomosing ; cells angulo-globose,
1-3G00" in diameter (Kiitzing, I. c. pi. 30).
BiBL. Hassall, Ah/. 300, pi. 78; Kiitzing,
Sp. Ah/. 225 ; Tab. Phyc. i. ; Thuret, Ann.
Sc. N. 3. xiv. 248, pi. 21 ; Niigeli, Einzell.
Alg. 71, pi. 2 ; Rabenht. Ale/, iii. 38.
TETRASPORES. See Spobes.
TETRATAXTS, Ehr. — A Valvuline
Foraminifer, with four chambers in a wdiorl.
Fossil (Carboniferous). (Parker and Jones,
Ann. N. H. 4. x. 259.)

TEXTILE FABRICS.— The components
of these are noticed under the heads of silk,
wool, fibrous and filamentous structures.

BiBL. VYiesner, Techn. Mikr. ; Schle-
singer, Mihr. Urdersuch. d. Gespinnffasern,
1872; Button, M. M. Jn. vii. 259; Lat-
teaux, Man. Techn. Micr.

TEXTULA'RLY, Def ranee (Textilaria,
Ehr.). — A protean genus of hyaline Fora-
miuifera, having typically a binary series of
subglobular or subquadrate chambers ar-
ranged alternately on two sides of a longi-
tudinal axis, and usually increa.sing in size
from the oldest (at apex) to the youngest,
with a slit-like apperture in the wall of
each chamber ( T. cvneifonnis, PL 23. fig. 47).
The shell is flattened in one direction in
Vuhulina, with oblique chambers and ter-
minal slit, V. gramen (PL 23. fig. 49); in
another, in Cuneolina, with transverse cham-
bers and a row of ap^rtural pores in normal
position. Irregularly alternate and biserial
chambers, passing into a short linear row,
with a necked and rimmed aperture, consti-
tute Heterostomella ; Bigenerina has many
uniserial chambers, with a tenninal poutirg
j mouth {B. agglutinans, PL 23. fig. 50).

TILILAMOPORA.

[ 7G4 ]

TIIECAMOKIDINA.

Instead of the biserial form, frequently
tlie shell begins with a triserial arrange-
ment of chambers ( l^erneuilina, with con-
tracted aperture ; Candeina ?, with perforate
septa). The Verueuiliue commencement is
often succeeded by the usual two alternating
rows {Gaudri/ina, G. pupoidea, PL 23.fig.48),
or by a linear growth with terminal aperture
( Tritadi(i). The triserial varieties are some-
times twisted. If T^idvtdiiia takes on the
linear growth, we have Venilina.

The early chambers of Textidaria and its
modiiications are not uufrequeutly coiled
(Spiroplecta). Textidaria (»S}j.) annectens
(Pi. 2-j. fig. 52), from the Gault, commenced
spiralh", proceeded biserially, and ended
with uniserial chambers.

Large Textiilarice are rarely porous and
translucent; they usually become sandy
{^Pleeuniiun).

Common in all seas, and fossil in all
formations from the Silurian upwards.

BiBL. D'Orbigay, For. Fuss. Vien. 24o;
Williamson, For. 75 ; Morris, Cat. Br. Foss,
4f3; Bi-oan, Index Pal. art. Text.; Ehren-
berg, Mikrog. ; Schultze, Org. Polyth. 62 ;
Carpenter, For. 189; Parker and Jones,
Ann. N. H. 3. xi. 91 ; 4. ix. 298, x. 189,
196, 259; Brady, Carh. For., Pal. Soc.
1876, 130.

THALAMOP'ORA, Eeuss. — A large,
subcylindric, zoophytoid Foraminifer, com-
posed of superimposed chambers, with laby-
rinthic and perforated walls, arranged around,
and opening into, a central vertical cavity.
Tludamopora exhibits characters of alliance
with Polgtrema, Carpcnteria, Tinoporus,
Ci/mbalopora, and, through the last, with
Planorhulina and others of the Rotalina. It
is among the Perforata what Ductylopura is
among the Imperforata. (Reuss, Geinitz's
Elhthak/ehmie, 1872, 139.)

THALASSICOL'LIUA, Huxley. — A
family of Radiolarian Rhizopoda.

Char. Composed of structureless cysts,
single or aggregate, containing cellular ele-
ments and sarcode, giving ofi" radiate pseu-
dopodia, which sometimes run into each
uther and form a network. Nucleus present,
l)ut no contracting vesicle. Numerous yel-
low cells occur scattered through them ;
and occasionally a few may be seen suspended
within the external gelatinous structure.

The whole organism is permeated by spicula,
or sustained by a fenestrated shell. The
most common genera are SphcBrozoum, Col-
losphcera, and Thalassivolla. They are ma-
rine, in tropical and subtropical seas.

BiBL. Huxley, Ann. N. H. 2. viii. 1851,
489; Qu. Mic. Jn. iv. 1856, 72; Miiller,
Thalass. ; Plaeckel, Radiolarien, 1862 ; Wal-
lich, Ann. N. II. 1869, iii. 97.

TllALES'TRlS, Claus. — A genus of
Copepodous Entomostraca. Ten species,
marine. (Bradv, Copep., Pag Soc. ii. 120.)

THAMNO'LIA, Ach.— A genus of Cla-
dodei (Lichenaceous Lichens).

T. vennicularis ; on mossy earth ; rare.
(Leighton, Lich. Fl. 74.)

THAMNOM'YCES, Ehr.— A genus of
Sphagriacei (Ascomycetous Fungi). It has
distinct asci and sporidia. (Berk. Br. Flor.
ii. pt. 2. 284; Fries, Su7n. Veq. 382.)

THAUMAN'TIAS, Esehscholtz. — A
genus of Campanulariidfe.

Char. Stem simple (or branched ? ), rooted
by a thread-like stolon ; cells campanulate ;
polypes with a funnel-shaped proboscis; re-
production by free medusiform buds.

T. inconspicua, Forbes. Common off the
Hebrides. (Hincks, Hi/d. Zooph. 178.)

THAUMATONK'MA, Grev.— A genus
of T»iatoniacea3. (Grev. Mic. Tr. 1863, 76.)

THECA. — A term used very loosely in
the descriptions of Cryptogamic plants. In
the case of the Lichens and Fungi it is syn-
onymous with Ascus, a sac in which free
spores are developed ; these are called theca-
spores or ascospores, in contrast with basi-
DiosPOEES or stylospores. In the higlier
Cryptogamia, as Ferns, &c., it is used in the
sense of sporangium.

THECAMONADI'NA, Divj.— A family
of Infusoria (=Cryptomonadina and some
Astasitea, E.).

Char. Usually coloured ; covered witli a
non-contractile tegument, which is either
hard and brittle, or membranous ; locomotive
organs one or more fiagelliform filaments.

Many are Algae, or their spores. They
are minute, usually green, but some are red ;
and they often colour stagnant water from
existing in vast numbers. They are mostly
recognizable by their rigidity ar.d the uui-
formity of their motion.

Dujardin subdivided them thus : —

' A single
llnf^clliform
ulameiit.

Body ovoid orj Tegument hard and brittle 1. Trachelomonas.

globular ( TegunK'nt membranous 2. Cri/pfo^iioiia/f.

Body depressed or ( with a tail-like urolongation 3. Phttcus (Ktigleini pt., E.)

folia'ceoiis 'l without a prolongation 4. CrumeinUti.

rp (Two similar filaments 5. Diselmis (Cklamid.omonas, E.).

fii *^°. -One flogelliform filament, and ( Body jirismatic or boat-shaped 6. Ploeotia.

niaments. / o„,, traUing retractile filament) Bodv ovoid or pip-shaiied 7. Anisonema.

, Several filaments Body prolonged into a point in front 8. Ojyrrhis.

TIIELIDIUM.

[ '65 ]

TJIYRSOPORELLA.

BiBL. Duiiirdin, Infus. 323.

TnELID'lUM,-Mass.— A geuus of Micro-
liehtnis parasitic on the thallus of Lecauor*.

Char. Spores subfiisiforiu, 2-looTilar, co-
lourless. (Lindsay. Qu. J\Iic. Jn. 18Gil, 340.)

THELOCAR'PON, Nvl.— A geuus of
Pyronodei (Lichenaceous Lichens).

Four species. (Leighton, Lich. Fl. 439;
Lindsay. Qu. Mic. Jn. 1809, 345.)

THELOTREMA, Ach.— A genus of Pla-
coidei (Lichenaceous Lichens), containing
two British species. (Lei^hton, Lich. Fl.
238.)

THEO'RUS, Ehr.— A genus of Rotatoria,
of the family Hydatinaea.

Char. Eyes colourless, more than three,
cervical, in two gi-oups ; foot forked ; jaws
each with a single tooth.

T. vernalis (PL 44. fig. 32). Toes small,
frontal hook absent. Aquatic; length 1-140
to 1-120".

T. uncinaUts. Toes long, frontal (or
rather cervical) region with hooks ; fresh-
water ; length 1-240".

BiBL. Ehr. Inf. 454 ; Pritchard, Inf. 000.

THLIPSU'RA, J. & H.— A Cytheroid
Ostracode in the Silurian strata. (Jones
and HoU, Ann. N. H. 4. iii. 213.)

THO'REA, Bory.— A genus of Batra-
chospermese (Confervoid Algte), of which
one species (T. ramosisshna) occurs in Bri-
tain; its fronds are olive-black, branched
filaments, a foot or more long, about as thick

740.

Thorea ramosiasima.
Horiisontal section of a filament (halved). The semi-
circular denser portion represents the axis, the loose
spreading branches the villi. Magnified 25 diameters.

as a crow-quill, with a villous siu-face. The
filaments are composed of radiating branched
cells, closely compacted into a kind of solid
axis, from which proceed lax, radiating ra-
muli, forming the villous surface. The
spores or sporangia! cells arise from these
ramules (fig. 740).

BiBL. Kiitz. Phyc. qeneralis, pi. 16, Sp.
Alg. 534 ; Emi. Bot. Supp. No. 2948 ; Has-
sail, Alg. 64; Rabenht. Ahj. iii. 418,

THOREL'IJA, Boeck. — A genus of
Copepodous Entomostraca. T. hrunnva, on
Laminaria. (Brady, Copep. i. 95.)

TIIUIA'RIA, Flem.— A genus of Polypi,
of the Order Ilydroida, and family Sertiila-
riid;v.

Char. Those of Sertularia ; but the colls
closely pressed to or imbedded in the stem
or branches. Two species :

T. thuia. Cells ovate-elliptical, acutish ;
vessicles pear-shaped. On shells from deep
water.

T. articulata. Cells ovate, obtuse or trun-
cate, vesicles elliptical ; rare.

Bibb. Johnston, Br. Zooph. 83 ; Gosse,
Mar. Zool. ii. 23; Iliucks, Iii/d. Zooph.

THU'JA, L.— A geuus of tjoniferte (Gym-
nospermous Plants), to which belongs the
arbor vitcc of gardens, Thuja occidentalis ;
T. oricntalis is placed by some authors under
another genus, Biota. The characters of
Coniferous wood, Gymnospermous ovules,
&c., may be observed in tliese plants (see
CoNiFERiE and Ovulk).

THURAjM'MINA, Brady.— a subglobu-
lar Arenaceous Foraminifer (0"5 mm.), with
perforate papillfe ; single and enclosing a
smaller chamber or group, and adherent.
Atlantic and Pacific. (H. B. Brady, Q. Jn.
M. Sc. n. s. xix. 45.)

THURIC'OLA, Kt.— A genus of Peritri-
chous Infusoria. Like Vaginicola, but sheath
with a closeable valve. Three species; salt
and fresh water. (Kent, /;//. 718.)

TH Y'AS, Koch. — A genus of Hydrachnea
(Acarina). Like Ilyclraclina, but legs formed
for w^alking. T. venusia. (Koch, Uebers. ;
Murray, Fc Frit., fig.)

THYMELEA'CE^.— An order of Di-
cotyledons to which the Spurge-Laurels
{Daphne) belong. In D. Lar/etto ( = Lagetta
lintearia) the fibres of the liber are separated
into lozenge-shaped meshes, arranged in
such beautiful and easily-separable layers,
as to have acquired for the plant the name
of the Lace-Bark Tree.
See Liber.

THYRSOPOREL'LA, Giimb.— Gumbel
' divides the Factyloporidcce (see Dactylo-
: pora) into (I.) those with chambers : —
I 1. Ilaploporella ; segmental, annular, or
i cylindrical (piled rings), with large cham-
I bers and simple traversing canals (0 species,
recent and Tertiary) : 2. IJavtyloporella ;
cylindricnl, with large and subsidiary cham-
bers, and branched traversing canals (4
species, Tertiary). (II.) Those without
chambers: — 3. Thy rsoporella ; cylindiical,

TIIYRSOPTERIS.

[ 7G6 ]

THYROID GLAND.

Avith simple, swolJeu, traversing canala, and
fa.<cicules of smaller tubes (2 species, Ter-
tiary ) : 4. Gi/roporeUa ; cylindrical, with
circular canals (14 species, Triassic and
Neocomian) : 5. Uteria ; annular, hollow,
perforate (1 species. Tertiary).

BiBL. Giimbel, Abhandl. k. hayer. AJcad.
Wiss. 11. a. xi. 1872, p. 231.

THYRSOP'TERIS, Kunze.— A genus of
Cyathese (Polypodiaceous Ferns), with glo-
bose, marginal sori, collected into a panicle

Fig. 745.

Fig. 741.

Fig. 742.

Thyrsoi^teris olegans.

Fig. 741. A fertile pinna.

Fig. 742. A pinnule converted into a cup-like Poru3.
Magnified 20 diameters.

distinct from the sterile pinnfe. Capsules
sessile, on a globose receptacle ; indusium
inferior, cup-shaped, the mouth entire. T.
eleijans, tropical. (Hooker, Si/71. 15.)

Fie. 743.

Fig. 744.

Thyrsopleris elegnns.
Fig. 743. Yertieal section of the same, with the spo-
ranges removed from the columella.

Fig. 744. Side view of a sporange. Magn. 100 diams.

TH Y^'ROID GLAND.— The thyroid gland
is one of the vascular gland.-*, or glands with-
out ducts.

It consists of rounded, closed, glandular
vesicles (tig. 745) surrounded by or imbedded
in a fibrous stroma (a), and aggregated into
rouiidi.sh, elongate, or somewhat polygonal
acini or minute lobules, these being grouped
in secondary lobules, which unite to form

Glandular vesicles from the thyroid gland of a child.
a, intervening c onnective tisbue ; b, basement mem-
brane ; c, epithelium.

Magnified 250 diameters.

lobes. The vesicles are from 1-600 to 1-240"
in diameter, the acini from 1-50 to 1-24' '.
The Strom a is condensed around the lobules,
to form a fibrous coat.

The stroma consists of ordinary interlacing
bundles of connective tissue, with fine elas-
tic fibres, at its outer surface containing fat-
cells.

Fiff. 746,

Glandular vesicles with- colloid matter
Magnified 50 diameters.

The vesicles consist of a basement mem-

TllYSANURA.

[ 767 ]

TINTINXUS.

brane (fig. 7 to b), liiu>d by a piuirlt^ layor of
polygonal epithelial cells (c'),aiKl coutaiuing
a veliowisb, tenacious, albumim)us liquid.

The capillaries form plexuses surrounding
tbe vesicles.

In f/oifre, tbe vesicles become greatly en-
larged, and continent, so as to form cysts
containing colloid matter, with tat-globules
and crystals of cholesterine. The same con-
ditions, iu a minor degree, are so frequently
met with, that tbej' can scarcely be regarded
as abnormal. The epithelium is also often
found loose in the vesicles (hg. 740), The
minute arteries and capillaries are often
t'oimd varicose.

BiBL. KiJlliker, Mik. An. ii. 327; Forster,
Pathol. An. ii. :233 ; Verson, Strieker's Hist.
i. 267.

THYSANU'RA.— An Order of Insects
(Spring-tails), to ■which Lepisma, Petrobiiis,
Podura, and Lepidocyrtus belong. See In-
sects.

BiBL. Lubbock, Thysanura, ^-c, Ray
Soc. 1873 ; Murray, Ec. Ent. 401.

TlCHOTHE'CiUM, Fv,— A genus of
Microlichens parasitic on the thallus of
many crustaceous and subfoliaceous lichens,

BiBL, Liudsav, Qu. Mic. Jn. 1809, .347.

TILLE'TIA, Tulasne,— A genus of Usti-
lagiuei (H^']3odermous Fungi), forming the
Bunt, a kind of blight of various corn-grains,
in which the ears are attacked, and the in-
ternal substance of the grains is replaced by
a foetid, black powder, consisting of the
spores of the fungus, T. Caries ( tlredo Ca-
ries, D.C.) attacks wheat and other grain.
The interior of the ovaries of the corn is at
fii-st occupied by an interwoven mycelium,
from which the globular spores arise on
short stalks; as the latter grow, the ears
become more or less deformed, the mycelium
disappears, and the spores are set free as a
pulverulent mass. The spores have a reti-
culated surface ; and their pedicel is often
found attached (PI. 27. fig, 13). A distinct
species is found in wheat in the United
States. (See Ustilauinki.)

BiBL, Berk. Br. Fl. ii. pt. 2. 375; Tu-
lasne, Ann. Sc. N. 3, vii, 112, pi. o ; 4. ii.
101,

TILLI'NA, Gruber,— A genus of Holo-
trichous Infusoria, Free, renitbrm, pha-
rynx curved ; longer ciha round the mouth
and the pharynx. T. mcujna ; freshwater,
(Gruber, Zeitsch. iviss. Zool. 1879, Jn. Mic.
Soc. 1880 ; Kent, Inf. 514,)

TIM'MIA, Hedw. — A genus of Mniaceous
Mosses, approaching Polytrichum in habit,

and M)iium in the form of the capsule. One
Jhitish .-pecies, Tiin/nia austriaca, on rocks
iu Scotland.

TlN'EA,Fabr. — AgenusofLepidopteroua
Insects, of the family Tineidaj.

The small scales from the underside of
the wings of 7'. vestianella, the common
clothes' moth, have been proposed as test-
objects; but they can hardly be regarded as
such for object-glasses of the present day.
The longitudinal lines form the test-struc-
ture.

BiBL. Westwood, 7?i^ro«?.; Stainton, 3/«-
nual of Butterflies.

TINOP'OR'US, Carpenter (Ue Montfort).
— A many-shaped Foraminiferal genus of
the Globigerinida ; globular, subhemisphe-
rical, lenticular, or stellate ; areolated, gra-
nulate, and often spined (baculate). Com-
mencing as a spiral Rotaline (like Calcariyui),
it soon heaps on each face subcyclical layers
of quadrangular chambers, with cribrate
floors and strong, perforated, radiating septa.
The spines consist of ''supplemental skele-
ton," arising from some of the early septa,
with an extension of the " canal-system."
Gypsina, Carter, is an allied but less elabo-
rate form.

Recent, often in great abimdance, as Tino-
porus baculatus of the Australian seas and
the Philippines.

BiBL, Parker and Jones, Ann. N. H. 3.
^•i, 34 ; Carpenter, For. 223 ; Carter, Ann.
N. H. 4. iv. 215 ; 5, v. 444,

TINTINNOD'EA,— A family of Pletero-
trichous Infusoria,

Kent includes in this family, Tintumus,
Tintinnidium, Vasieola, and Strombidinoi)sis.

TINTINNID'IUM, Kt, — A genus of
Heterotrichous Infusoria. Like Tintinnus,
but contained in a mucilaginous cylindrical
sheath, adherent to foreign bodies. Three
species; marine and freshwater. (Kent,
Inf. Oil.)

TINTINNOP'SIS, Stein,— A genus of
Heterotrichous Infusoria. Like Tiidinnxs,
but with two independent rings of anterior
cilia. T. beroidea, marine, (Kent, Inf. 617.)

TINTIN'NUS, Schrank. — A genus of
Heterotrichous Infusoria, family Tintin-
nodea.

Char. Single ; body contained in a cylin-
drical, sessile, bell-shaped carapace, to the
bottom of which it is attached by a stalk.

Many species.

T. inquilinus (PI. 32. fig. 4). Body hya-
line or yellowish ; carapace cylindrical, hya-
line. Marine; length 1-240''.

TISSUE. [ :

BiBL. Ehr. Inf. 294 ; id. Ber. Berl Ak.
1840 ; Duj. Inf. "561 ; Ann. JV. K. 1879, iv.
290; Clap, et Lacli. Inf. 195; Kent, Inf. G03.

TISSUE, FiBEO-PLASTic. — A term ap-
plied by Lebert to imperfectly developed
abnormal connective tissue. The separate
elements are often found diffused through
normal tissues, or products of inflammatory
exudation. They consist of rounded or
oblong cells, froiu 1-2300 to I-KjOO" in dia-
meter, in a more advanced stage becoming
fusifonii or angular, and finally forming di-
stinct hbres ; hence resembling the elements
of embryonic connective tissue (PI. 49. fig.
42). In some instances the development is
arrested at one of the early phases, so that
the tissue consists almost exclusively of the
rounded or the fusiform cells; and in others,
the cells enlarge and produce a number of
nuclei or secondary cells (PL 38. lig. 10 c).

Eibro-plastic tissue or its elements are
met with in inflammatory efl'usions upon the
serous and synovial membranes (but rarely),
in the interstitial effiisions of pneumonia,
especially when chronic, in cirrhosis of the
liver, in the products of suppurating sur-
faces, on the surface of chronic ulcers and
non-malignant fungoid vegetations, in the
soft yellow vascular tissue occupying the
cancelli of ulcerated bones, in certain tu-
mours, &c.

BiBL. Lebert, Thys. Path. ; Wedl, Path.
Hist. ; Fbrster, Path. Anat. i. ; Riudfleisch,
Path. Geioebcl.

TISSUES, Animal.— The following syn-
optical arrangement of the principal animal
tissues, according to their structure, is in-
tended to facilitate reference to the various
articles scattered through the work.

A Simple.

1. Blaslemic or protoplastic . Barcode.

2. Memt)ranoii.s Basement membrane.

(Fatty tissue ; epithelium ;
nerve-cella ; simple
cartilage ; unstriated
muscular fibre.
(Without secondary depo-
sit ; true cartilage.
With secondary deposit ;
bone.
C Connectivetissue; tendon;

5. Fibrous < ligament; elastic tis-

l_ sue ; muscle.

6. Fibrmis and cellular Pibro-cartilage.

(Without secondary de-
posit. Vessels.
With secondary deposit.
Nerve-tubes.

B. Compound. Glands ; mucous and serous mem-
branes ; skin ; synovial membrane ; teeth.

BiBL. Ucydig, ///■s;'. 18-16; Morel, Hist.
18G4 ; KiJlliker, Ic. Hist. 1805; Briicke, £■/<'/«.
Organism. ) 'BeolQ, Simple tissues', Exner,

68 ]

TISSUES.

Leitf. thier. Gtncehe, 1873 ; Ranvier, Hist,
technique ; Thin, Hist. 1877 ; Schafer,
Pract. Hist. 1877; Gibbes, Hist. 1880;
Klein and Smith, Atlas Hist. ; Ork, Hist.
1881 ; Thierfelder, Atlas path. Hist. 1881 ;
Satterthwaite, Hist. 1881 ; Stirling, Hist.
1881.

TISSUES, Vegetable.— The tissues
of which vegetables consist are all composed
of cellulose sacs or cells, most of them re-
taining their primary form, constituting
cellular tissue, which makes up the greater
mass of plants ; while others undergo com-
paratively slight, yet characteristic modifi-
cations in form, consistence, and in their
mode of union to form other tissues. The
tissues may be divided into groups on dif-
ferent principles; but for our purpose a
simple arrangement will suffice, based
chiefly on the character of the compound
tissues, leaving the secondary divisions to
be determined by the nature of the compo-
nent cells.

Cambium tissue, occurring in the growing
regions of all plants having stems, is com-
posed of minute cells of variable form,
densely filled with protoplasm, and without
intercellular passages. It is a transitional
structure, forming the first stage of all the rest.

Parenchyma, or ceUular tissue, is com-
posed of cells in which the diameter is
not excessive in any one direction, and
the walls are comparatively thin. This is
divided by authors into many sections, ac-
cording to the form of the cells, the laxity
of their coherence, &c. The only distinc-
tions worth note are between : —

a. Parenchyma proper, where the cells
have polygonal forms.

b. Merenchyma, where the cells are round,
oval : &c.

c. Collcnchyma, a form of cellular tissue
where the walls are greatly thickened
with softish secondary deposits ; it
occurs beneath the epidermis of many
herbaceous plants, in the fi-onds of the
larger Algae, of Lichens, &c.

d. Sdercnchyma. Where the secondary
deposit or thickening is hard, as in the
bony cellidar tissue of the shells, stones
of fruits, Sic.

prosenchyma. Cellular tissue, usually
forming the mass of wood and various
fibrous structures, where the cells are atte-
nuated to a point at each end, the cells, or
fibres, being intercalated and applied side to
.side.

Tela conte.vta. This name is used to

TISSUES.

[ 709 ]

TONGUE.

indicate the interwoven tissue formed by
the ramified jointed filanieuts of the my-
celium of Fungi, and the cottony substance
in the interior of the thaUus of many
Lichens.

I'ibro-vasculartissiieis composed of vessels,
ducts, and prosenclnnnatous cells or "fibres"
associated in various ways, forming fibrous
or fibro-vascular bundles, which either re-
main distinct or cohere to form masses of
wood.

a. Fibrous bundles, occm'ring in liber, in
the outer part of many Monocotyledo-
nous stems, and in the stems of Mosses,
consist of cords formed of prosenchy-
matous cells, which are often of great
length.

b. Fibro-vascular bundles, composed of
vessels and ducts together with pros-
enchyma, form the woody fibres of
every part (except the bark) of all
plants above the Mosses.

c. Sieve-tubes or Clathrate tissue, foimd in
the bark of Dicotyledons and in the
vascular bundles of Monocotyledons.

Laticiferous tissue and Heservoirs for Se-
cretion, composed either of intercellular
passages lined by a proper coat, or of lines
of cells fused at their ends, so as to form
continuous branched canals ; they occur in
the bark, wood, and pith of the Flowering
Plants.

Epidermal tissue. Composed of cellular
tissue, forming a continuous firm layer over
the external surface of the higher plants.
It is composed usually of a single layer of
cells, and presents veiy varied appendages,
such as Hairs, Gi.ands, &c., and is per-
forated by Stojiata. Its outer surface is
rendered dense by the deposit of Cuticle.
The epidermis is replaced, on stems, by the
CoBK or suberous layer of Bark.

BiBL, Henfrey-Masters, Bot. ; Sachs,
Bot. ; V. Tieghem, Bot. 1881; and the Bibl.
of the above heads.

Fig. 747.

Tmesipteris tannensis.

TMESIP'TERIS.— A genus ot Psilotefe
(Lycopodiacea^), remarkable for its peculiar
habit and bivalvod sporanges bursting by a
vertical crack. See LYCOPODiACEiE.

TOBACCO.— The leaves of Tobacco (M-
cotiana Tabacnm and other species) may be
distinguished from the leaves of the plants
commonly used for adulteration by the pecu-
liar structure of the Epidermis with its
hairs (PI. 2. fig. 16), and the form of the
section of its Fibro-vascular bundles. Paper,
which has been sometimes used, is still
more readily detected. The epidermis of
the dock-leaf (PI. 2. fig. 17), that of rhu-
barb (fig. 18), and of colt's-foot (fig. 19),
are also characteristic. As in other similar
cases, the nature of a foreign ingredient
can only be determined by careful compara-
tive investigations,

Bibl. Hassall, Food 8fc. ; Prescott, To-
bacco and its Adulterations, 1858.

TO'DEA, Willdenow.— a genus of Os-
mundaceous Ferns (figs. 748-50). Four spe-
cies. Exotic.

Fig. 748. Fig. 749.

Fig. 750.

Todea africana.

Sporanges closed and bursting.

Magnified 40 diameters.

TOLYPOTH'RIX, Kiitz.— A genus of
OsciUatoriacefe (Coufervoid Algje), appa-
rently uot very satisfactorily defined. Has-
sall describes six species as British, of which
T. distorta (PI. 8. fig. 14) is said to be com-
mon, adhering to sticks, stems, &c. in stag-
nant water, forming tufts from 1-2 to 1" in
height, dark green when fresh, verdigris- or
blue-green when dry ; primary filaments
1-1800 to 1-1440" in diameter; joints about
as long as broad. Tolypothrix Dilhoynii—
Desfnotietna, Eng. Bot. Supp. no. 2958,

Bibl. Kiitz. Sp. Alg. 312 ; Tab. Pkyc. ii.
pis. 31-33; Hassall, Alg. 240, pis. 68 & 69 ;
Rabenh. Aly. ii. 273.

TONGUE.— We have only space here to
notice the beautiful papillae of the tongue.

The filiform or conical papillae (fig. 755)
are whitish, very numerous, and occupy the
intervals between the umgiform papillae.

3d

TONGUE.

[ 770 ]

TONGUE.

The papillae of the mucous membrane at
their bases (p, p) are conical, and covered
either at the end only, or all over the siu--
face with a number of smaller or secondary
papillfe ; the whole being coated by an epi-
thelial investment (e), terminating in a tuft

Fig. 751.

<^-

of free filiform processes (f). The inner
layers of the epithelium agree in structure
with that of the mouth, whilst the outer
layers, and especially the epithelium of the
processes, resemble rather the scales of the
epidermis, in their hardness, small size, and

Fig. 753.

Fig. 752.

Fig. 754.

Fig. 7•^l. Fungiform papilla, covered by the epithelium e on one side, and with the secondary or simple papillae p.
Magnified 35 diameters.

Fig. 752. The same, with the vessels; the epithelium e represented in outline, a, artery; v, vein; d, capillary
loops of the simple papilla; c, capillaries in the simple papillae of the mucous membrane at the base of the fun-
giform papilla. Magnified IS diameters.

Fig. 75:3. Perpendicular section of a human ciroumTallate papilla. A, proper papilla; H, wall; a, epithelium;
6 6, nerves of the papilla and wall ; c, secondary papillse. Magnified 10 diameters.

Fig. 754. Follicular gland from the root of the human tongue, a. ejathelium; b, paiiillfp of the mucous mem-
brane ; c, areolar coat ; e, cavity ; /, epithelium hning it ; gg, tolUcles in the thick capsule. Magnified 30 diameters.

considerable resistance to the action of
alkalies and acids. The papillse themselves
consist of areolar tissue, with a large num-
ber of undulating nuclear fibres, each con-
taining a small artery («) and vein {v), with
intermediate plexus of looped capillaries,
and numerous nerve-tubes.

The fungiform or clavate papillse (fig. 751)
are reddi.sh, distributed over the entire sur-
face of the tongue, and are very numerous
at its point. Each has at its base a club-
shaped mucous papiUa, and is covered all
over with simple or secondary conical pa-
piUse {p,p) ftnd a simple epithelial layer (e),

without filiform processes. The vessels Cfig.
752) are more numerous, but otherwise re-
semble those in the filiform papillas.

The circumvallate or lenticular papillae
(fig. 753) consist of a flattened central pa-
pilla (A), surrounded by an elevated wall or
ridge {B). The flat surface is furnished with
crowded conical secondary papillae (c), the
whole being covered ■with epithelium (a)
free from processes. The wall appears as a
simple fold of the mucous membrane, and
also exhibits beneath its smooth epithelial
coat numerous rows of simple, conical, se-
condaiy papillte. In other respects these

TONGUE.

[ 771 ]

TONGUE.

papilljB do not differ essentially in structure
li'om tlie fungiform.

In some of the papilla) of the tongue,
axial bodies are found resembling those in
the papillae of the skin.

The epithelial processes of the filiform
papillne are often covered by a fungus (Lpp-
tothrix), the mycelium closely surrounding
them, \\-hilst some of the filaments project
from the surface.

Fig. 755.

Two human filiform papillae, one with epithelium.
p, p, papillse ; a, v, artery and vein, with the capillary
loops ; e, epithelial covering ; J", its processes.

Magnified 35 diameters.

The glands of the tongue consist of mu-
cous and follicular glands.

The mucous glands resemble those of the
mouth (Mouth).

The follicular glands are most numerous
between the epiglottis and the circumval-
late papillae, and are so superficially situated
as to form projections of the mucous mem-
brane. They form lenticular or globular
masses, from 1-24 to 1-6" in diameter, im-

bedded in the submucous tissue ; and in the
middle of the free surface is the orifice
(754 (!) of a conical cavity (e), formed by a
depression of the mucous membrane. Each
gland forms a thick-waUed capsule, sur-
rounded by a fibrous coat (c) contiimous
with the deeper portion of the mucous
membrane, and lined internally by a pro-
longation of the mucous membrane with
papillae and epithelium {b, a) ; and between
the two are closed capsules or follicles (ff),
imbedded in a fibrous and vascular basis.
The follicles are from 1-120 to 1-48" in
diameter, rounded or somewhat elongate,
whitish, composed of a coat of connective
tissue without elastic fibres, and wdth grej'-
ish-white contents consisting of cells I-6OCO
to 1-4000" in diameter and free nuclei.

In the small portion of tissue constituting
one of the papillae of the frog's tongue,
Beale found striped muscular fibres, capil-
lary vessels, pm-ely sensitive nervous fibres
forming an expanded terminal plexus at the
summit of the papilla, motor nerve-fibres
distributed to the muscle, nerve-fibres
around the capillary vessels, and a few very
fine nerve-fibres ramifying in difterent parts
of the papillae. All of these are imbedded
in and held together by connective tissue,
forming the body of the papilla, the summit
of which is surmounted by a peculiar epithe-
lium-like tissue, perhaps connected with
the nerves and belonging to nerve-texture,
while its sides are covered with ordinary
ciliated epithelium. The fur of the tongue,
which is usually considered to be composed
of epithelium, is stated by Butlin to consist
of Schizomycetous fungi.

BiBL. Todd and Bowman, PIii/s. ; Ward,
Todd's Cijcl. An. 8>- Phjs.\ Salter, ibid.;
Huxley, Mic. Jn. ii. 74; Beale, Phil. Tr.
1864, and Hoto i^-c. ; Hartmann, Miiller's
ArcMv, 1863 ; Klein and Verson, Strieker's
Hist. V. 1 ; Butlin, St. Barth. Hosn. Rep.
1879, .37.

TONGUE OF MOLLUSCA.— The tongue,
odontophore, or palate of the Mollusca, has
long formed an interesting microscopic ob-
ject on account of the elegant horny or
chitinous teeth situated upon it, in nu-
merous rows and in various patterns

The tongue forms a shorter or
ribbon-like structure, attached behind to the
bottom of a sac or sheath, situated on the
lower wall of the pharynx. It is supported
by a cartilaginous cushion, over which it
works backwards and forwards by muscular
action.

3d2

longer

TONGUE.

[ 772 ]

TONGUE.

It exists in the Gasteropoda, the Ptero-
poda, and the Cephalopoda.

It consists of a central strip or band,
called the rachis, and two lateral bands, the

Fig. 755*.

DQaoMQDOQgQDQDDSaaaOOiJ

ftfc^

Tongue of Whelk ; with separate teeth t- Magnified
10 diameters, the teeth 40 diameters.

pleuree. In the rachis, the teeth often rather
resemble overlapping toothed plates, the
teeth being straight, while the pleural teeth,
or uncini of the lateral bands, are usually
curved and more or less serrate.

Fig. 755**.

Row of teeth of the tongue of the Periwinkle.
Magnified 120 diameters.

They may be easily examined m the lim-
pet {Patella), the whelk [Buccinuni), or in
the freshwater snails, Lyimiceus, Planorhis,
Sec.

In the tongue of many terrestrial Gastero-
poda, as the snaU (Helix) and slug {Limax),
the number of plates in each row is veiy
considerable, amounting to 180 in the large
garden-slug (Lwiax tnaximus) ; whilst in
many marine Gasteropoda, sucli as the com-
mon whelk (Bucciniwi undatum), the tongue
has only three plates in each row, one bear-
ing the small central teeth, and the two
others the large lateral teeth. Generally
speaking, the tongue of the terrestrial Gas-
teropoda is short, and contained within the
nearly globular head; but the closely-set
rows of teeth are usually very numerous,
frequently more than 100, and in some
species as many as 1(50 or 170; so that the
total number of teeth may mount up, as in
Helix jwmatia, to 21,000, and in Limax

maximus to 26,800. The transverse rows
are usually more or less cm'ved, whilst the
longitudinal rows are quite straight; and
the cm-vatm'e arises on each side from the
central longitudinal row, the teeth of which
are symmetrical ; whilst in those of the late-
ral portions of each transverse row, the
prominences on the inner side of each tooth
being suppressed, those on the outer side
are increased, this modification augmenting
in degi'ee as we pass fi-om the central line
towards the edges. The tongue of the
marine Gasteropoda is generally longer, and
its teeth larger ; and in manj' instances it
extends far beyond the head, which may,
indeed, contain but a small part of it. Thus
in the common limpet {Patella) the princi-
pal part of the tongue is folded up, but per-
fectly free, in the abdominal cavity, between
the intestines and the muscular foot; and
in some species its length is twice or even
three times as great as that of the entire
animal. In a large proportion of cases the
tongue exhibits a very marked separation
between the central and the lateral portions
— the teeth of the central band beuig fre-
quently smaU and smooth at their edges,
whilst those of the lateral are large and
serrated. The tongue of Trochus zizyphimis
is one of the most beautiful examples of
this form — not only the large teeth of the
lateral bands, but the delicate leaf-like teeth
of the central portion having their edges
minutely serrated. A yet more complex
type is found in the tongue of Haliotis, in
which the central band of teeth has nearly
straight edges instead of points, with on each
side a lateral band consisting of large teeth
shaped like those of the shark, and beyond
this, again, another lateral band on either
side, composed of several rows of smaller
teeth. Very curious differences also present
themselves among the diflerent species of
the same genus. Thus in Doris jiHosa the
central baud is almost entirely wanting, and
each lateral band is formed oi a single row
of very large hooked teetji, set obliquelj' ;
whilst in JJoris tnberculata the central band
is most developed, and contains a number of
rows of perpendicidarly conical teeth, like
those of a harrow. In Dendronotm, the
central and lateral teeth are very finely and
beautifully serrated.

In Littorina, the periwinkle, the tongue is
2^ inches long, coiled like a watch-spring,
and contains about GOO rows of teeth.

The tongues may be preserved either in
the dry state, or in glycerine or in balsam .

TONSILS.

[ 773 ]

TORULA.

many of them in Ihe Latter medium forming
beautiful |)olanzing objects.

The iuipei'feetly cleansed ton"^ies, when
stained with Judson's dyes, also form beau-
tiful objects.

ikr.L. Carpenter, Microscope; Thomson,
Todd's Ci/el. An. ^-Phi/s. iv. 1 142 • Ann. N. H.
2. vii. 8G; Gray, ?6. 2. x. 413 ; Macdonald,
ih. 1868, ii. 236, 1869, iii. 113; Maplestone,
Mn. Mic. Jn. 1872, 4.5 ; Hogg, Ti\ Mic. Soc.
1868 ; Lov^n, (Efversujt Kongl. Vetensh. Ak.
Fdrhandl. 1847; Troschel, Gchiss d, Schmc-
ken (36 pis.), 1875 ; Woodward, Mollusca.

TONSILS. — Tliese organs may be re-
garded as consisting of from ten to twenty
follicular glands, resembling those found at
the root of the tongue, surrounded by a
common fibrous coat or capsule.

The blood-vessels are numerous, forming-
elegant networks around the follicles. (Kcil-
liker, Hist, ; Klein & Versou, Strieker's
Hist.)

TOPAZ.— The crystals of this mineral
consist principally of silicate of alumina,
with the fluorides of aluminium and sili-
cium.

Sections of topaz &c. often exhibit micro-
scopic cavities, frequently containing crys-
tals and one or two non-miscible liquids,
the latter sometimes including bubbles of
gas or vapour.

Brewster recommended the spherical
cavities as the best objects for examining
the aberrations of lenses, and as infinitely
preferable to globules of mercury.

BiBL. Brewster, Edinh. Phil. Tr. x. &
xvi. ; Microscope, 186.

TORQUATEL'LA, Lankester. — A
doubtful genus of Infusoria. Body rounded,
with an anterior funnel-shaped frill of un-
didating membrane ; no cilia, vacuoles, or
nucleus. Marine, in Bay of Naples. (Lan-
kester, Qu. Mic. Jn. 1874, 272.)

TOR'TULA, Hedw. See Barbula.

TOR TIL A, Pers.— A genus of Torulacei.
The plants ordinarily referred here appear to
be somewhat heterogeneous in their nature.
In what may be considered the true species,
the chains of spores form Ihe principal bulk
of the plants, little or no filamentous myce-
lium existing. Other forms very generally
included under this head agree in their
characters with Oidium, which itself is a
doubtful genus, probably founded on the
conidiiferous states of more perfect kinds.
But in T. sacchari (or cerevisice), the Yeast-
fungus, usually referred here, we find both

forms presented; for when actively vege-
tating in fermenting liquids, it presents the
characters shown in PI. 26. fig. 23, while,
while the liquid becomes exhausted, por-
tions of tlie fungus float to the top, and
produce a filamentous structure, terminating
in cliains of spores, such as are represented
in PI. 26. fig. 24, and in fig. 756. The
simply beaded form is taken as the type of
a genus Cnjptococcus by certain authors,
some of whom consider it a Fungus, others

Fig. 756.

Tonila sacchari (aerial form).
Magnified 200 diameters.

(Kiitzing especially) an Alga. The same
varieties of form occm* in the Vinegar-
plant ; and in both cases Penicillium (flau-
eum seems invariably to succeed the pre-
ceding when kept at a moderate tempera ■
ture. Thus between all these various forms,
together with Oidium lactis, there appears
to be a relation, not yet clearly made out,
indicating that they probably represent
different states of the same plant grow-
ing under different conditions of nutri-
tion and temperature. Further remarks on
this head are made imder Yeast and Vi-
negar-plant. A growth similar to T.
sacchari presents itself sometimes in decom-
posing urine (PI. 26. fig. 7) from healthy
subjects ; and indeed scarcely any decom-
posing animal or vegetable fluid, in which
there exist fermentible elements, remains
long free from Torula-like growths, if left
exposed to the air (see Fermentation).

We find it impossible to give definite
characters for the species that have been
enumerated. T. herharum is a common
form gi-owing on decaying stems of plants ;

TORULACEI.

[ 774 ]

TORULACEI.

it forms at first erect greenisli tufts, which
afterwards become bhtckish, ramify and
form a black crust, the spores readily sepa-
rating. T. Spurendonema, a form growing
on decaying cheese, represents the Sporen-
donema casei of Desmazieres. T. Fumago
is now separated with other forms under
the genus Capnodium. T. alUrnata also
is the type of the genus Alternahia.

BiBL. Berk. Br. Fl. ii. pt. 2. 359 ; Ann.
N. H. i. 203, vi. 439 ; 2. v. 400, xiii. 400 ;
Fries, Syst. Myc. iii. 499 ; Sum. Veyet. 505 ;
Fresenius, Beitr. z. Myc. Heft ii. 58, pi. 6.
fig. 55 ; Corda, Ic, Funr/orum.

TORULA'CEI.— Afkmily of Coniomyce-
tous Fungi, forming moulds and mildews on
decaying vegetable substances, or acting as
ferments in decomposing yegetable and ani-
mal fluids. They are compound microscopic

Fig. 757.

Fig. 759,

Fig. 758.

Fig. 757. Speira toruloides. Magnified 200 diameters.
Fig. 758. G-yrocerus ammonis. Magnified 200 diams.
Fig. 759. Trimniatostroma salicis. Magn. 200 diams.

"cylindrical or beaded filaments, simple or
ramified, the joints of Avhich (all or part)
separate from each other to form the spores.
There is no definite receptacle liere; the
mycelium grows as a cottony web over or
in the infected body, or forms clouds or
flocks in liquids. Much obscurity prevails
respecting the genera included below, and
it is indeed doubtful whether any of them
are independent productions. Some species
of Torv.la, such as T. cerevisicfi (the Yeast-
fungus), appear intimately connected with
certain Ilyphumycetous genera, perhaps

merely representing their conidiiferous forms
(see Torula). Achoriox, again, seems to
be merely the spermogonous form of a Peni-
cilUum. Sporendonema is founded appa-
rently on imperfect observation ; (S. muscce,
the true characters of which are given under
that head, has been renamed Enipusa ; and
its proper position is among the Saprolegnei;
but it would appear to be referable to the
Mucorini. Dictyospormm, Speira, and Trim-
■matostroina appear to consist merely of the
spores of some other genera; Gyrocerus
cannot be regarded as a perfect form ; and
indeed all the genera require a thorough
examination in a fresh state.

Synopsis of Oenera.

Torula. Spores in beaded chains, simple,
readily separating, placed on a short con-
tinuous or septate pedicel (PI. 26. figs. 7 &
23). _

Bispora. Resembling the last, but the
spores uniseptate.

Septonema. Resemblingthe preceding, but
having several transverse septa in the
spores.

Alternaria. Resembling the preceding,
but with cellular spores connected b}^ a
filiform isthmus.

Sporidesmimn. Spores in tufts, straight,
subclavate or fusiform, shortly stalked or
sessile, transversely septate or cellular.

Tctraploa. Spores sessile, quadri septate,
coherent in bundles of four, each spore
crowned with a bristle.

Sporochisma. Filaments erect, simple, ex-
ternal membrane inarticulate, cell-contents
at length separating into spores, articulated
in fours, emerging.

Coniothecium. Spores without septa, col-
lected in heaps, finally separating more or
less into a powder.

Echinobofryum. Spores rounded-apicu-
late, collected in fascicles, attached on simple,
erect, anuulated filaments.

Spiloccea. Spores globose, simple, adhering
firmly together and to the matrix, forming
spots laid bare by the separation of the epi-
dermis of the .subject infected.

Sporcyidonema. Described as composed of
erect filaments, containing single rows of
spores in the interior. S. muscce {Empusa,
Cohn) really consists of short, tufted, erect,
simple filaments, terminating in a bell-
shaped cell (spore or sporange :■), thrown off
with elasticity when mature.

TOURMALINE.

[

775 ]

TRACIIELTNA.

Achorion. Mycelium somewhat ramose,
articulated, joints terminatin<r iu round, oval,
or irregular spores (conidia ?).

Speira. Spores connate into concenhic
filaments, fovminpr laminse resembling a
horseshoe, tinnlly separating.

Tri»UJ>afossfroinn. Spores more or less
curved, multiseptate, chained in beaded
rows, finally separating.

Gi/rocerus. Spores connate into spirally
coiled filaments, finally separating.

Dicfi/osporium. Spores tongue-shaped, re-
ticuliirlv cellular (fig. 172, p. 2(10).

TOURMALINE.— Sections of the crys-
tals of this mineral, cut pnrallel to the axis,
were formerly used as polarizers or ana-
lyzers. They are now usually replaced by
Nicol's prisms (Introduction, p. xx).
Crystals of the quiuiue-salt (Quinine) form
cheap substitutes for either. The crystals of
tourmaline belong to the rhombohedric
system. They consist principally of silica
with alumina, containing also boracic acid,
magnesia, iron, &c. ; but their composition
is not constant.

Good tourmalines are transparent, brown-
ish or pinkish ; the colourless ones do not
polarize.

BiBL. Pereira, Polarized Liff/tt; Nau-
mann, Mineraloqie, .310.

TOUS-LES-MOIS.— A kind of fecula
consisting of the starch of species of Canna,
remarkable for the large size, great transpa-
rency, and numerous striae of the granules
(PI. 46. fig. 25). The mixture of any of the
common kinds of starch Avith Tous-Ies-mois
is readily detected by microscopic exami-
nation. The granules are excellent sub-
jects for studying the physical characters of
starch, iu particular the appearance with
polarized light (PL 39. fig. 40), &c. See
Staech.

TOXONIDEA, Donkin.— A proposed new
genus of Diatomaceas, the fi'ustules of which
resemble those of Fleurosir/mn, except that
the longitudinal line is curved on each side
of the median nodule in the same direction,
so as to resemble a bow. Two species.

T. Grerioriana (PI. 51. fig. 24).

BiBL. Donlrin, Micr. Jn. 1858, vi. 12 ;
Rabenht. Ah/, i. 243.

TRACHE'A. See Lungs.

TRACHE'vE OF Insects, &c.— The re-
spiratorv tubes of Insects and Arachnida.

Traclieffi (PI. 34. fig. 17 ; PI. 35. fig. 2 h)
are cylindrical tubes containing air. They
are broadest at their origin from the spira-

cles, afterwards branching freely, the minute
branches being distributed to all parts of the
body and anastomosing freely. By reflecti'd
light they appear white, with a metallic
lustre, or slightly iridescent ; l)y transmitted
light the snuiller ones are black, the larger
usually of a violet tint.

The tracheoe consist of two coats, between
which lies a spiral fibre (PI. 34. fig. 17) ; in
the larger trunks a second external envelope
exists. The fibre becomes more slender and
indistinct in the smaller tracheal branches,
until it finally disappears. The outer mem-
brane appears to arise from the confluence
of cells ; for iu the tracheae of caterpillars
and other larvae of insects, the remaining
nuclei are visible (PI. 34. fig. 17). The
inner coat forms a pavement epithelium.
The spiral fibre arises from the splitting up
of a homogeneous membrane deposited in
the space bounded by the confluent cells of
the outer membrane.

In many insects the trachefe are furnished
with dilatations forming air-sacs, in which
the spiral fibre is absent.

AVhen larvae are fed with indigo or car-
mine, or when the dorsal vessel is injected
with colouring-matter, the tracheae become
coloured, which some authors believe to
arise from the nutritive liquid circulating
between the membranes of the tracheae ;
whilst by others this circulation, or the ex-
istence of a space between the tracheal
membranes, is denied.

BiBL. That of Insects ; Newport, Phil.
Tr. 1836, 529; Platner, Miiller's Archiv,
1844, xxxviii.; Stein, Verr/l. Anat. Insek-
ten; Agassiz, Ann. Sc. Nat. 3. xv. ; Bassy,
ibid. ; Joly. ibid. xii. ; Blanchard, Compt.
Rend. 1851 ; Ann. N. II. 1852, ix. 74; Du-
four, Compt. Bend. 1851, Ann. N. H. 1852,
ix. 435; Meyer, Siebold S,- Kolliher's Zeitschr.
i. 175 ; Moselev, Pi'oc. Roy. Soc. No. 153.
vol. xxii. 344, 1874 ; Gerstacker, SieboJd S,-
Kollikers Zeitschr. W. 204, 1874; Landois,
Zeit. iviss. Zool. xvii.

TRACHEA OF Plants.— This name
was formerly .applied to the unreliable
Spiral Vessels of Plants, from their resem-
blance to the tracheaj of Insects.

TRACIIELI'NA.— A family of Holo-
trichous Infusoria.

Char. Body without regular spiral teeth
or foot ; parenchyma excessively contrac-
tile ; mouth and oesophagus very dilatable.

BiBL. Clap. & Lachm. Inf. p. 291.

TRACHELIUS.

[ 776 ]

TRAGACANTH.

/ Mouth ter-
rninal.

w

o

<

Month not
terminal.

Synopsis of Genera.

/■Anterior part of ^ Body more or less cylin- /Mouth on the summit

I body with a J drical, moving by-^ of the appendage

conical appen-j turning on axis. \ Mouth at its base

dage. I Body flat, swims without turning on axis

C (f^n i„o, ,„„ /^Body attenuate infront

I No inter- J '-°.:J^^^< Body not attenuate in

No conical
[ pendage.

ap-

' (Esophageal
teeth present.

No oesophageal
teeth.

nal teeth. i '"■"•

V Leaping cirri

front

I ( Body attenuate in front

I Internal teeth -/Body not attenuate in

No cirri .

\ front

j Body never much flattened

'( Body much flattened

A bundle of cirri, simulating a foot

A row of spherical vesicles, each enclosing a very

refractive body

No lateral (A branched intestine...

lamina. 1 No branched intestine .

A broad marginal lamina of compact

tissue

No vesicles

e b

teryn
Phialina.
Trachelophyllum .
Enchelys.

Holophrya,

TJrotricha.

Enchelyodon.

Prorodon.
Nas»ula.
Chilodon.
Trichopvs.

Lojrodes.

Trackelius.

Ampkiieptus.

LoxophyllMin.

TRACHE'LirS, Ehrenb.— A geniLs of
Holotrichous Infusoria, fani. Tract elina.

Char. Mouth situated at the base of the
trunk-like prolongation, alimentary canal
apparently branched. No row of spherical
yesicles or lateral lamina.

T. ovum (AmiihUei^tus omim, Duj.), in
bog-water. Trachelius himella (PI. 32. fig. 5)
is a Lo.xophyllmn. (Clap. & Lachm. Inf.
345.)

TEACIIELOCER'CA, Ehr.— A genus
of Holotrichous Infusoria =Zof7'?/w«r2rt.

2'. olor=^Laa'ymaria olor.

T. m'ridis (PI. 31. fig. 33). Body green;
neck as in the last; freshw. ; length 1-120".

BrBL. Ehr. lif. 341 ; Clap. & Lachm.
Inf. 295; Kent, Inf. 514.

'TRACHELOM'ONAS, Ehr.— A genus
of Infusoria, family Ci-yptomonadina.

Char. Body enclosed in a spherical or
ovoid hard and brittle envelope, having a
small aperture, from which a long flagelli-
form filament projects ; eye-spot present.
Freshwater.

T. vokocina (PL 30. fig. 24 d, empty en-
velope). Spherical, green, brownish, or red;
eye-spot red; length 1-8G5".

T. niyricans. Ovate-globose, green, black-
ish brown or reddish ; eye-spot brownish ;
length 1-1780".

T. cylindrica. Oblong-subcylindrical ;
bright green ; eye-spot red ; length 1-1000".

Other species.

The bodies represented in PI. 30. fig. 24
(h tor/), and which are commonly found in
bog-water, probably belong here, with the
genera Chcetoyhnaici), Chcetotyjyhla (tig. 26),
and Doxocoeciis (fig. 47). The margins of
the red envelope appear as a bright red
ring, on account of the greater thickness

traversed by the light. They are probably
spores of Algse.

BiBL. Ehrenberg, Inf. 47 ; Kent, Inf. 388.

TRACHELOPHYL'LUM, Clap. &Lach.
— A genus of Trachelina (Holotrichous In-
fusoria).

Char. Anteiior part of the body with a
prolonged appendage, which has no circlet
of cirri ; body flat, without a lateral marginal
lobe. Swims without turning on its axis.
Two species ; freshwater. (Clap. & Lachm.
Inf 3U6.)

TRACHYL'IA, Fr.— A genus of Micro-
lichen.s, parasitic on Pertusarice.

Char. Thallus granular ; apothecia cu-
puliform, sessile, black. Spores blackish,
1-septate. Three species, on old posts.
(Lindsay, Qu. Mic. Jn. 1869, 140 : Leighton,
Lich. Fl 470

TRACH'YTE. See Rocks.

TRADESCAN'TIA, L.— A genus of
Commelyuacese (Monocotyledons), com-
monly cultivated in gardens under the name
of Spider-worts. These plants are cele-
brated for having served as material for
some of the most remarkable observations
on the physiological processes of vegetables
— as the Rotation of the cell-contents,
and the multiplication of the cells, so well
seen in the hairs of the stamens when young
(PI. 47. figs. 8 & 9). The stems, petioles,
vvc. afi'ord beautiful spiral, annular, and re-
ticulated vessels, kc.

TRAG'AOANTH.— A gum derived from
various .-species of Adrayalns, not con.^isting
of a formless exudation, but of partty dis-
organized collenchymatous tissue which is
extruded from the medullary raj's. It is
often used for fastening opaque objects, as,
when dry, its surface is duU, unlike gum-

TREBIUS.

[ 777 ]

TRICERATIU^r.

arable. We have some of the solution which
has been kept twelve years in a corked bottle
with a piece of camphor, and it is as good
as if freshlv prepai-ed.

TRE'BIUS, Krliyer.— A genus of Crus-
tacea, order Siphonostoma, family Caligida).

Cltar. Head in the form of a large buck-
ler, with the large frontal plates destitule
of sucking-disks ; thorax three-jointed, seg-
ments uncovered ; legs four pairs, with long
plumose hairs, fourth pair slender and two-
branched; autennfe small, Hat, and two-
jointed; second pair of foot- jaws two-
jointed, and not in the form of a sucking-
disk.

T. caudutiis. Found upon the body of
the skate. Male much smaller than the
female.

BiBL. Baird, Entomostraca, 280 ; Thomp-
son, Ann. N. H. 1847, xx. 248.

TREMATO'DA.— An order of Entozoa,
containing the tiukes. See Distoma.

TREMELLI'NI.— A family of Hymeno-
mycetous Fungi, consisting of polymor-
phous, often convoluted or lobed, more or
less gelatinous masses, growing upon
branches or stumps of trees, in crevices of
the bark, or on the dead wood. The
hymenium extends over the whole of the
upper exposed surface, and, from the recent
researches of Tulasne, appears to present
remarkable characters. The gelatinous
substance of these Fungi is composed of
ramified filaments, with more or less effused
mucilage between them. In Tremella a
portion of the filaments terminate at the
surface at fu"st in expanded globular cells
(PI. 27. figs. 3, 4), which Ijecome divided
by vertical septa into fom' somewhat pyri-
form cells (bastdia) ; fi'om each of these
arises a slender filament {stengma\ which
terminates in a slender point tipped with a
globular spore (^stylospore or basidiospore) .
Other filaments coming to the surface in
like manner ramify extensively, with short
divergent branches, finally bearing nume-
rous minute globular bodies (sjjermatia),
solitary or in groups of four, which, hke the
basidiospores,f all ofl'and rest on the hymenial
surface, involved in jelly, but, imlike those,
do not germinate. The basidiospores are
about 1-.3000" in diameter, the spermatia
about 1-12000". In Tremella mesenterica
the surface covered with basidiospores as-
sumes a whitish colour, the layers of sper-
matia and the jelly are orange.

In Exidia the production of the basidio-
spores is similar ; but the spores are reni-

form and unilocular, about l-2.')00" long
and 1-5000'' in diameter, Spermatia have
not been detected.

In Dacryimjces the basidia are represented
by simple clavate or bifurcate branches at
the hymenial surface, these terminating in
points bearing single reuiform spores ex-
hibiting three septa (quadrilocular). In
germination some of these spores produce
a long filament from each loculus ; others
behave difierently, producing the spermatia
of the plant, each loculus sending out a
short pointed process bearing a globular
cellule exactly resembling the spermatia of
Tremella. Other examples of Dacrijmyees
bear a different kmd of reproductive bodies,
apparently representing conidia. In these
the peripheral filaments terminate in a mass
of many-j ointed Torula-Wke processes, which
ultimately break up into the separate joints,
(See Dacbymyces.)

BiBL. Berk. Br. Fl. ii, pt, 2, 215 ; Ann.
N. H. 2. xiii. 406, pi. 15. fig. 4 ; Tulasne,
Ami. Sc. Nat. S. xix. 193, pis. 10-12.

TRENTErOH'LIA, Mart. = CJianiran-
si'a and Chroolepus sp.

TREPOM'ONAS, Duj.— A genus of Fla-
gellate Infusoria, family Monadina.

Char. Body compressed, thicker and
rounded behind, twisted in front into two
narrowed lobes, Avhich are inflexed laterally,
and each terminated by a flagelliform fila-
ment, which produces a very lively rotatory
and jerking motion.

T. ar/ilis (PI. 32. fig, 6). Body granular,
unequal; length 1-1100". In decomposing
marsh-water. (Dujardin, Infus. 294 ; Kent,
Inf. 300.)

TRIAR'THRA, Ehr.— A genus of Rota-
toria, of the famdy Hydatinsea.

Char. Eyes two, fi-outal ; foot simply
styliform ; body with lateral cirri or fins,

^lovement jerking. Jaws two; each bi-
deutate.

T. longiseta (PI. 44. fig. 30). Eyes dis-
tant, ciiTi and foot nearly three times as long
as the body ; length 1-216",

T. mydacina.' Eyes approximate ; cirri
and foot scarcely twice as long as the body,

T. breviseta (Gosse), Cirri much shorter
than the body.

BiBL. Ehr. Inf. 446 ; Gosse, Ann. N. H.
1851, viii. 200; Pi-itchard, Infiis.

TRICERA'TIUM, Ehr.— A genus of
Diatomacefe.

Char. Frustules free ; valves triangulai",
areolar, each angle mostly with a minute
tooth or short horn.

TRICHIA.

[ 778 ]

TEICHINA.

T.fams (PI. 17. fig. 29). Valves plane
or convex, angles obtuse, with horn-like
processes ; areola hexagonal ; marine ; dia-
meter 1-240' '.

T. alternans. Angles of valves slightly
elevated ; areolfe circular ; marine.

T. striolatumi?). Angles subacute; areo-
lation faint ; brackish water.

BrBL. Ehr. Ber. Bed. Ak. 1840 ; Smith,
Br. Diat. i. 26 ; Kiitz. Baeill. 138, and Sp.
Alff. 139 ; Brightwell, Micr. Jn. 1858, 158;
Rabenht. Ah/, i. 315,

TRICHIA, HaD.— A genus of Myxo-
niycetes (Gasteromycetous Fungi) gTowiug
upon rotten wood '&c., characterized by a
stalked or sessile, simple, membranous peri-
dium, which bursts at the summit, whence
the densely interwoven free capillitium ex-
pands elasticaUy, carrying with it the spores.
The capillitium is composed of tubular fila-
ments {elaters), containing spiral-fibrous
secondary deposits, like the elaters of Mar-
chantia (PL 40. fig. 39). In some species
the elaters bear numerous little spinidose
processes. The genus is divisible into two
groups. In the first {Hemiarci/ria) the
dehiscence of the peridium is obscurely cir-
cumscissile (fig. 760), the capillitium dense ;
these are always stalked, usually of reddish
colour when young. Some species have the
peridia fasciculate on a compound peduncle
(fig. 760), others separate. In the other
division ( Goniosjwra) the dehiscence of the
peridium is irregular, the capillitium lax,
the peduncle short or absent, the colour at

Fig, 760.

Trichia rubifonnis.
Maguifled 25 diameters.

first whitish, changing to yellow, and the
spores rather angular. In 2\ serpnla and
reticulata the sessile peridia are irregular,
flexuous, serpentine or annular bodies ; in
most of the other species the peridia are

pvriform, turbinate, or of some analogous
form. The elaters (PI. 40. figs. 39 & 40)
are interesting objects, and form good tests
for the defining-power of the microscope
under very high powers. They must be
mounted in a verv thin stratum of liquid.

EiBL. Berk. Br. Fl. ii. pt. 2. 319 ; Ann.
N. H. vi. 432, 2. v. 367 ; Fries, Syst. Myc.
iii. 182 ; Sum. Veg. 457 ; Greville, Crxipt.
Fl. pis. 266, 281 ; Henfrey, Linn. Tr. xxi.
221 ; Currev, Mic. Jn. iii, 15, v. 127.

TPJCHtNA, Owen.— A genus of Ne-
matoid Eutozoa.

T. spiralis (PI. 21. figs. 16,^7, 18), as
ordinarily seen, inhabits the human body,
forming opaque white specks, visible to the
naked eye, in the voluntary muscles. The
worms usually exist singly within a cyst situ-
ated between the muscular bundles (fig. 16).
At each end of the cyst is a group of fat-
ceUs resembhng those of ordinary tatty tis-
sue. The cysts are about 1-50" in length,
elliptical or oval, usually narrowed and
slightly produced at the obtuse ends, and
consist of numerous structureless laminae,
in which are frequently imbedded minute
granules consisting of fatty or calcareous
matter. The worm is cylindrical, narrowed
towards the anterior end, the posterior end
being obtuse and rounded. The integument
is transversely striated or annular, and ex-
hibits an anterior and a posterior longitudi-
nal muscular band. The mouth (fig. 17 a)
is situated at the anterior extremity, from
which a small papilla is sometimes protru-
ded. The first part of the alimentary canal
is very narrow, and leads to a broader sac-
culated portion; this behind the commence-
ment of the posterior half of the body ter-
minates in a funnel-shaped expansion (fig.
18 c), the remainder of the canal being
narrow and lined with pavement epithelium
(fig. 18 d). The manner in which the pos-
terior end of the alimentary canal terminates
is doubtful — whether directly continuous
with the anal orifice, or free in the abdomi-
nal cavity. Luschka describes tliree valves
as existing at the posterior end of the body.
At the commencement of the funnel-shaped
portion of the alimentary canal (fig. 16 ft)
are two rounded glandular sacs. The re-
productive organs are not well known,
.lust below the funnel-shaped portion of the
alimentary canal is the ctecal origin of a
tubular .sac (figs. 17 & 18 c), containing a
dark granular-looking body (fig. 17 d\ fig.
IS e) near its commencement ; this extends
to the posterior end of the worm, where it
either terminates in^ the anus or in the

TRICHOCEPIIALUS.

[ 779 ]

TRICHODACTYLUS.

abdoiiiinal cavity. Luschlia regards this
aj( the male orj^-aii, and the dark-looking
body as the testis; but no spermatozoa have
been detected.

Some of the cysts and worms are found
in a state of fatty degeneration, with gra-
nides or globules of fat, and calcareous
matter.

Trichina is admitted to the human body
with the food. It exists iu two different
conditions. In one it is sexually immature;
and it then inhabits the muscles, of the pig
or rabbit for instance, in vast numbers, each
worm being coiled up in its capsule or cyst.
It is incapable of further development under
these circumstances. But if a portion of
the muscle be eaten by a warm-blooded
vertebrate animal and so introduced into
the alimentary canal, the immediate de-
velopment of young TrichincB is the result.
The immature worms escape from the cysts,
grow larger, develop sexual organs, and
produce viviparously a numerous progeny.
The young Trichiiice thus produced perfo-
rate the waUs of the digestive system, and
after working into the muscles become
encysted.

Tt is important that every one should know
the appearance of meat infected with this
worm, as it produces serious disease, and
even death. It is stated that 8 per cent.
of the slaughtered American pigs contain
Trichince.

Three or four other doubtful species have
been described.

BiBL. Owen, Zool. Tr. i. .315: Luschka,
SieboM ^- Koll. Zeitschr. iii. 69; Bristowe
and Raiuey, Tr. Path. Soc. v. 274; Duj. Jlel-
minthes, 29.3 ; Herbst, Ann. Sc. Nat. .3. xvii.;
Kobelt, Valentin s Rep. 1841 ; Leuckart,Pa?-. ;
Bakodv, Sieh. ^- Koll. Zeit. 1872, 422 ; Vir-
choWj'Qu. Mic. Jn. 1861, 44; Cobbold,
Parasit. 149 ; and the Bibl. of Entozoa.

TRICHOCEPH'ALUS,Goeze.— Agenus
of Nematoid Entozoa.

Char. Body elongate, composed of two
parts, the anterior longer and capillary, the
posterior becoming suddenly broader ; spi-
culum of male simple, long, and surrounded
by a sheath.

' The species occur in the large intestine,
principally the caecum of man and the mam-
malia.

T. dispar (PI. 21. %. 19, the male; fig.
21, the female).

Anterior portion of the body, spiral in the
male, containing the oesophagus only, or
the fii'st moniliform portion of the intestine ;

posterior portion containing the rest of the
intestine and the reproductive organs. Anus
situated at the posterior obtuse end of the
body. Integument transversely striated,
and with a longitudinal band studded with
papilL-B (PI. 21. fig. 20). Oviduct termi-
nating at the point of junction of the two
portions of the body ; ova (fig. 21 «) oblong,
covered by a resistant shell, with a short
neck at each end.

BiBL. That of Entozoa.

TRICHOCO'LEA, Nees.— A genus of
JungermanniefB (Hepaticse), containing one
British species, T. {Jung.) tvmentella, grow-
ing in moist places in the Avest and north of
England, Scotland, and Ireland. It is re-
markable for the character of the leaves,
which are cut up into compound capillary
segments, giving the plant a spongy texture.
Colour pale.

BiBL. Hook. Brit. Fl. ii. pt. 1. 127 ; Br.
Jung. pi. .36 ; Ekart, Si/nops, Jung. pi. 6.
fig. 49 ; Endlicher, Gen. Plant. Supp. 1. no.
472, 15.

TRICHO'DA, Mull.— Agenus ofPIolotri-
chous Infusoria.

Char. Free, ovate or club-shaped, trun-
cate in front ; mouth anterior, with a lip or
vibratile membrane ; cilia very fine, oral
larger.

T. pur a, oblong attenuate in front ; iu
putrid infusions, of haj^ &c. ; length 1-720".

T. carnium, in putrid- flesh water.

T.pyrum.^ in pond water.

T. angvlata, I)uj. (PI. 32. fig. 7), oblong,
obliquely and irregularly folded or angular,
with one or more superficial vacuoles ; fresh-
water; length 1-700".

BiBL. Ehr. Inf. 306 ; Duj. Inf. 395.

TRICHODACTYLUS, Dufour.— A ge-
nus of Acarea (Acarina).

Rostrum short, with minute setae ; fourth
pair of legs longer than the rest, without
claws, but terminated by a verj' long seta.

T. Osmice. Glabrous, pale red, with two
marginal setae on each side ; legs and pos-
terior part of the body darker ; length l-oO' '.

T. Osnii(e, on an Osmia ; T. Xylocopce, on
Xylocope ; another species in hornets' nests.

Murray unites the three genera. Hypo-
pus, Trichodactylus, and Homopus into a
family, Ilypopidae ; while Megnin declares
them to be the nymphae of Acarea.

In all, the hinder pair of legs is rudimen-
tary, hairs replacing claws.

iJiBL. Dufour, Ami. Sc. Nat. 2. xi. 276 ;
Gervais, Walchcnaer'' s Apteres, iii. ■■2i^Q j
Murray, Ec, Ent.251 ; Megnin, Paras. 146.

TRICHODECTES.

[ 780 ]

TRICHOGASTRES.

TRICHODECTES, Nitzscb.— A genus
of riiilopteridse (Anoplura).

Char. Antennae filiform, three-jointed;
maxillary palpi none or inconspicuous ;
mandibles two-tootbed ; tarsi with one law.

T. latus (PL 36. fig. 6). Abdomen pale
fulvous ; bead and tborax ferruginous yel-
low ; bead subquadrate, witb two l^lack spots
in front, and a black lateral band on eacb
side ; abdomen oval.

Common upon dogs, especially puppies.

Other species, upon cattle, the horse, ass,
deer, sheep, cat, &c.

BiBL. Denny, Anoplur. 186; Murray,
Ec. Ent. 383 ; Mt^guin, Paras. 80.

TRICHODER'MA, Pers.— A genus of
Fungi, placed by Fries among the Gastero-
mycetes. The plants are characterized by
a romidish peridium composed of inter-
woven, ramified, septate filaments, evanes-
cent at the summit ; the spores minute,
heaped together, at first conglobated. T.
viride, growing on fallen trees, has a white
villous peridium, and dusky-green globose
spores. The peridia appear as scattered
spots 1-20 to 1-8" or more in diameter. It
is a conidiiferous state of Hypocrea rtifa.

BiBL. Berk, Br. Fl. ii. pt. 2. 323;'Gre-
ville, C^-ypt. Fl. pi. 271 ; Fries, Sum. Vey. 417.

TRICHODES'MIUM, Ehrenb.— A genus
of microscopic Alga?, apparently belonging
to the Nostoehaceae, discovered by Ehren-
berg to produce the red colour over large
tracts in the Red Sea, and found also in the
Atlantic and Pacific Oceans by Darwin and
Hinds, and in the Chinese Sea. No vesi-
cular cells or spermatic cells have been de-
tected ; hence the characters are as yet
imperfect. Montague has separated the
plant of Hinds from Ehrenberg's ; and Kiit-
ziug characterizes two species in his Sjt.
Alf/amm, and figures them in his Tahnlfe
Flnjcoloijkxe ; but neither the figures nor the
descriptions indicate any very marked dift'e-
rences.

T. Ehrenherfjii, Montagne. Blood-red (at
length becoming green) ; bundles widish,
confluent ; tilaments 1-3000" in diameter,
joints about twice as wide as long. Found
floating in vast strata in the Red Sea by
Ehrenberg and Dupont, and in the Yellow
Sea (China).

T. Hinclsii. Blood-red, with a strong
odour; bundles longish, slender; joints
twice or thrice as broad as long, transversely
granulated.

See also on the species, and on the red
coloration of the sea by plants, Montague's

papers in the Ann. Sc. Nat. 3. ii. 332,
vi. 202 ; 4. i. 81 ; Ami. N. II. 2. xix. 431 ;
Rabenht. Ah/, ii. IGl.

TRICHODI'NA, Ehr.— A genus of Peri-
trichous Infusoria, family Vorticellina.

Char. No tail, nor pedicle; cilia absent
from the surface of the conical or discoidal
body, but forming a frontal crown or a tuft ;
oral orifice not spiral.

T. pedicultis ( Ureeolaria stellina, D.) (PI.
31. fig. 16). Body discoidal, the imder and
upper surfaces each with a crown of cilia.

Parasitic upon Hydra vulyaris and viridis.
Breadth 1-575 to 1-200". On the under
sm-face is an annular imdulatory membrane ;
and within and at the base of this is a horny
ring, with an outer and an inner row of teeth,
forming an organ of adhesion.

T. mitra. Parasitic upon Planaria torva.

T. grandhiella and T. vorax, on Halteiina.

T. tentaculata. Body discoidal, cilia large,
forming a tuft ; a styliform, tentacle-like
process present ; diam. 1-290".

BiBL. Ehrenberg, Inf. 265; Dujardin,
Inf. 527 ; Siebold, Siebold vnd Kdlliker's
Zeitschr. ii. 361 ; Stein, Inf. 174 ; Claparede
& Lachmann, Inf. 128 ; Ivent, Lif. 647.

TRICHODINOP'SIS, CI. audLachm.—
A genus of Heterotrichous Infusoria. Free,
conical ; an anterior oral ring of cilia, and
a posterior suctorial disk. T. paradoxa, in
the mucous cavities of Cyclostoma. (Clap.
& Eachm. Inf 133 ; Kent, Inf. 614.)

TRICHODIS'CUS, Ehr.— A genus of
Rhizopoda, family Actinophryina, D.

Char. Body depressed, stalkless ; seta-
ceous tentacles forming a simple row at the
margin of the bodv.

T. sol (PI. 32. fig": 8). Body suborbicular,
hyahne or yellowish, tentacles variable;
diameter 1-432 to 1-216".

BiBL. Ehr. Inf 304.

TRICHOGAS'TER, Sterki.— Agenus ol
Hypotrichous Infusoria. Free, ovate, ven-
tral surface ciliated, a few larger cilia in
front and behind. T. jnlosns, freshwater.
(Sterki, Zeits. iviss. Zool. 1878 ; Kent. Inf.
764.)

TRICHOGAS 'TRES {Puff-halls).— K fa-
mily of Gasteromycetous Fungi, character-
ized by the contents of the leathery peridium
breaking up when mature into a pulverulent
mass of spores and filaments, without a
central column, the whole being expelled by
the bursting of the case .(see Gastkuomy-

CETES).

BiBL. Berkley, Ann. N. H. iv. 155; Tu-
lasne, Ann. Sc, N, 2. xvii. I.

TRIOHOMANES.

C 781 ]

TRICHORMUS.

TRTCirOM'ANES,^ Linn.— A genus of
Ilyuiouophyllaceous Ferus, of elegaut aud
delicate uabit.

Fig. 761.

Fig 762.

Trichomanes alatum.

Fig. 761. A pinnule. Magnified 5 diameters.

Pig. 7(52. Section through a sorus, showing the vein
prolonged as a columella, and continued out beyond the
border. Magnified 25 diameters.

Fig. 763.

A sjiorange, with horizontal anuulus. Magnified 100
diameters.

Many species ; tropical. T. hrevisetum
{radicans), British. (Hooker, Syn. 79.)

TRICHOM'ONAS, Donne.— A genus of
Flagellate Infusoria.

Char. Free, soft, ovate, with two anterior
and one posterior flagella, and a dentate
lateral undulating membrane ; no mouth.

T. batrachorum, in the intestine of frog
and toad.

T. vcujinalis (PI. 32. fig. 9). Body glu-
tinous, nodular, unequal, frec[uently be-
coming agglutinated to other objects; move-
ment vacillating ; length 1-2500". Found
in morbid vaginal mucus.

T. limacis (PI. 32. fig. 10). Body ovoid,
smooth, pointed at each end; movement
forwards, by revolution upon its axis ;
length 1-1600". Found in the intestine of
Limax agrestis.

BiBL. Dujardin, Infiis. 299; Kent, Bif.
308.

TRICHONE'MA, From.— A genus of
CUio-Flagellate Infusoria. Free, ovate,
variable ; flagellum single; body with short

cilia. T. /drsuta; h-eshwatev. (Kent, Inf.
409.)

TRICHONYM'PHA, Leidy.— A genus
of Ilolotrichous Infusoria. 7\ Of/i/is, in the
intestine of the American white ant.
(Leidy, Pi'oc. Ac. Philadvlphia, 1881 ; Kent,
Inf. 533.)

TRIOHOPH'RYA, 01. & Lachm.— A
genus of Acinetina. Like PodojjJtrya, but
fixed without a pedicle ; tentacles in scat-
tered bundles; vesicles numerous; nucleus
band-like. Two species ; on the stalk of
EinstyHs pliccdilis, aud on Entomostraca.
(CI. & Lachm. Inf. 386; Kent, /«/. 811.)

TRICHOPH'YTON. See P.vbasites.

TRIC'HOPUS, Clap. & Each.— A genua
of Hypotrichous Infusoria.

Char. Body depressed, with a bundle of
long ventral cirri near the posterior end of
the body ; a tuft of caudal cilia, and a group
of pharjTigeal teeth.

T. dysteria ; marine. (Claparede & Lach-
mann. Inf. 338.)

TRICHOR'MUS {Anahcena, Bory, Bre-
bisson, Kiitzing, Montague, «.tc.). — A genus
of Nostochacese (Confervoid Algse), grow-
ing on wet earth, and rising to the surface of
lakes, brackish ditches, &c., forming an in-
determinate stratimi, at first nearly colour-
less aud transparent, with the filaments
sparingly scattered through the mass; the
filaments afterwards increasing rapidly in
number, causing the mass to become opaque ;
deep bluish green, and occasionally mottled
with brown, especially beneath. Filaments
mostly short and moniliform. Cells more
or less globular ; the spermatic cells resem-
bling tlie ordinary cells more in this than
in the allied genera. The filaments closely
resemble those of Nostoc ; and some of the
floating aquatic species can only be distin-
guished from that genus by the absence of
definite form or size, and of the hardened
peridenn. It differs from Dolichos])cnnmn
in the globular shape of its sporangia, aud
from Sphterozyya and Cylindrospermiim in
the arrangement of its vesicular and sper-
matic cells, which are in Trichormus sepa-
rated by ordinary ceUs. In PI. 8. fig. 2, we
have represented what appears to be a new
species.

T. Jlo&-aqu<s. Filaments flexuous or
ciu'ved, moniliforn\; cells orbicular, vesi-
cular ones larger, terminal aud interstitial.
Ralfs, Ann. N. H. 2. v. pi. 8. fig. 2. Anor
baina Jl.-aq., Kiitz. S^). Ah/. ; Trichormus
incurvatus, AUman, Ann. N. H. xi. 163;
HassaU, AUjce, pi. 75. Rising to the surface

TRICHOSPH^RA.

[ 782 ]

TRINACEIA.

of stagnant pools or other still waters, in
gelatinous bluish or green masses.

T. spiralis. Filaments coiled or spiral ;
vesicular and spermatic cells orbicular.
Ralfs, I. c. pi. 8. fig. 3 (?). Anahaina spi-
ralis, Thompson, Ann. N. II. t. 81 ; Spiril-
lum Thompsoni, Hassall, Br. Fr. Algce,
pi. 75.

T, Thivaitesii. Filaments moniliform,
flexuous ; ordinary cells globular or nearly
so ; vesicular cells larger, globular when
interstitial, ovate when terminal, ciliated;
sporangia oval, catenate. Ralfs, I. c. pi. 8.
fig. 4. Salt marshes, forming thin, gela-
tinous dark-green patches, on damp soil or
the bottom of ditches, then floating and
abounding in spermatic cells.

T. oscillarioides. Filaments elongate,
flexuous; ordinary joints subquadrate ; ve-
sicular cells barrel-shaped or elliptic, naked ;
spermatic cells oval, catenate. Ralfs, /. c,
pi. 8. fig. 5. Bluish green, in brackish
ditches.

T. rectus. Filaments bright green,
straight. Ralfs, I. c. pi. 8. fig. 6 ; in pools.

BiBL. Ralfs, Ann. N. H. 2. v. pi. 8;
Rabenht. Ah/, ii. 293.

TRICHOSPH.E'RA, Semper.— A genus
of Rotifera. T. cEquatorialis is spherical,
the rotatory organ consisting of an equato-
rial zone of cilia ; found among worms,
infusoria, &c. in the rice-field ditches of
Zamboanga; diameter 1-36." (Semper, <SVc6.
8i Koll. Zeitschr. 1875, Mn. M. Jn. xiv. 237.)

TRICHOSPO'RIUM, Fr.— A genus of
Mucedines (Hyphomycetous Fungi), nearly
allied to Botrytis, characterized by a ctes-
pitose mycelium, whence arise fertile conti-
nuous filaments, bearing solitary, simple,
acrogenous spores. T. nigrum= Sporotri-
cliuni niffrum, Fries
(Syst. Mt/c), Botrytis
nigra, Link.

BiBL. Fries, Sum.
Veg. 492 ; Grev. Crypt.
Fl. pi. 274.

TRICHOS'TOMUM,
Hedw. — A genus of
Pottiaceous Mosses, so
called from the hair-
like peristome, resem-
bling closely that of
Barbula ( Tortilla),
but with the teeth

straight instead of Tnchostomumrigiduh.m.
twi.sted; in T. rigidu- Fragment of the ikti-
lum, however (fig. 764), stome with filiform teeth,
there exists a slight Magnified lOO diameters.

Fig. 764.

J'^uJ^'

curling even in this genus. The Tricho'
stoma grow on the ground and on stones.

TPJCHOTHE'CIUM, Link (Diplospo-
rium, ejusd.). — A genus of Mucedines (Hy-
phomycetous Fungi), growing upon dead
sticks, herbaceous parts of plants, &c., form-
ing a cajspitose entangled mycelium, from
which arise erect fertile filaments, bearing at
the summit a few acrogenous, free, didymous
spores. From some observations recently
published by Hoifmann, and confirmed by
Bail, the spores of T. roseum, when they
germinate, produce a mycelium whence
arise fertile filaments of Verticillium ru-
berrimum, the " spores " of which they con-
sequently consider to be the spermatia of this
plant. Several species are British, as T.
roseum, obovatuni {IJactylium, Berk.).

BiBL. Berk. Br. Fl. ii. pt. 2. 348 : Ann.
N. H. vi. 437, pi. 14 ; Greville, Crgpt. Fl.
pi. 172 ; Fries, Sum. Veg. 492 ; Hoffmann,
Bot. Zeit. xii. 249 ; Bail, ibid. xiii. 673.

TRICHY'DRA, Wright.— A genus of
Hydroid Zoophytes.

Char. Stem creeping, branched; cells
rudimentary, consisting of very short tubular
processes at intervals on the creeping stem ;
poh-pes cyhndrical, very slender and exten-
sile, with a short conical proboscis. T. pu-
dica, marine, on shells &c. (Hincks, Ili/d.
Zooph. 215.)

TRILOCULI'NA, D'Orb.— A subgenus
of Miliola, with the chambers aggregated
on three opposite faces, embracing, three
only apparent.

Many species, both recent and fossil.
M. (Tr.) trigomda (PI. 23. fig. 4).

BiBL. Williamson, Bee. Brit. For. 84
(Miliolina) ; Carpenter, For. 78.

TRIMAS'TIX, Kt.— A genus of Fla-
gellate Infusoria. Free, ovate, with a lateral
membranous border; flagella three, ante-
rior, one directed forwards, the others
trailing.

T. marina. Li salt water with decaying
plants ; length 1-1400". (Kent, Inf. 312.)

TRIMxMATOSTRO'MA, Corda (fig. 759,
p. 774). An obscure genus of Toru-
lacei (Coniomycetous Fungi), perhaps
founded on the spores of Phragmatotri-
chum. (Corda, Icon. ; Fries, Sum. Vea.
475.)

TRINA'CRIA, Heib.— A genus of Dia-
tomacese.

Char. Frustules with three broad, bi-
spined, equal-lengthed processes, margin
pearly, angles naked. Danube.

BiBL. Rabenht. Alg. i. 317.

TRINEMA.

[ 783 ]

TRITON.

Ficr. 765.

TRIXE'MA, Duj.— A genus of Rliizo-
poda, family Actiuophryina.

Char. Carapace menibranous, diaphanous,
elong-ate-ovoia, naiTower iu front, with a
large oblique lateral oritice ; expansions two
or three, tiliform, very slender, as long as
the carapace.

T. acinus=Difflugia enchelys, E. (PI. 32.
fig. 11, after Ehr. In Dujardiu's tigure the
expansions are represented as much more
slender.)

BiBL. Duj. Inf. 249; Clap. & Each. Inf.
455.

TRIXO'TON, ^iizsQ]i=^Liotheum pt.

TRIOPHTHAL'MUS, Ehr.— A genus of
Rotatoria, of the family Hydatina^a.

Char. Eyes three, red, cervical, in a trans-
verse row; foot forked; jaws single-
toothed.

T. dorsalis (PI. 44. fig. 31). Body crys-
talline, turgid, suddenly attenuated at the
foot, which is half the length of the bodv.
Length 1-48 to 1-36". (Ehrenberg, Inf.
450.)

TRIPHRAG'MIUM, Link.— A genus of
L^redinei (Hypodermous Fun-
gi), distinguished by their tri-
locular spores (fig. 765). T.
uhnarice ( Uredo tdmarice, Brit.
Fl.) grows upon the leaves of
Spircea uhnaria, forming orange,
subsequently blackish, effused
patches, bursting from beneath „ • v .
the epidermis. Tulasne has "ulmarS!™*
shown that it possesses all three A pedicellate
forms of reproductive structure jiagi^-gei 350
of the L'redinei, A'iz. 1. spermo- diameters,
gonia with spermatia ; 2. Uredo-
fi-uits, with ellipsoid or globose stylospores ;
and 3. perfect fruits, arising either among
the stylospores or in special sori, containing
stipitate three-lobed spores (fig. 765), each
lobe of which is unilocular and exhibits a
single pore in its black tubercular outer coat.
The last germinate in the spring, and pro-
duce from each pore a tubular filament
which becomes divided into fom- or five
chambers, from three or four of which arise
single styliform processes (sterigmata), each
bearing a small smooth spherical sporidium.
The globular stylospores also germinate (in
the first summer), but produce only a long-
filiform process, probably the rudiment of a
new mvcelium. (See Ueedinei.)

BiBL. Berk. Br. Ft. ii. pt. 2.368; Tulasne,
Ann. Sc. Nat. 4. ii. 181, pi. 10; Fries, Sum.
Veq. 513 ; Currev, Micr. Jn. v. 126.

TRIPLO'CERAS, B&±=Docidium sp.

I"

TRIPOSPO'RIUM, Corda.— A genus of
Dematiei (liyphomycetous Fungi), charac-
terized by the three-lobed septate spores.
T. elegans (fig. 766) has been found in this

Fig. 766.

Triposporium elegans.
Magnified 200 diameters.

country on bare oak-trunks. Another spe-
cies, T. Gardneri, forms a blight in the co ffee
plantations of Ceylon.

BiBL. Berk. Ami. N. H. 2. vii. 98 ; Hortic.
Jn. iv. 8.

TRITAXTA, Reuss. See Textularia.
(Reuss, Sitz. Ak. Wien, xliv. 383.)

TRITICEL'LA, Dalyell.— a genus of
Ctenostomatous Polyzoa. Cells moveable ;
no gizzard. Three species. (Hincks, Polyz.
542.)

TRI'TON, Laur. (water-newt).— A genus
of Reptiles.

If a male and female T. cristatus (fig. 767),

one of the common water-newts, be kept in
a glass jar with healthy water-plants, they
will lay their eggs upon them. The larvae
are veiy beautiful microscopic objects for
showing the circulation in the gills and
tail, the chorda dorsalis and the embryonic
tissues; they should be kept in a vessel
separate from the parents ; otherwise these
will devour them.

The injected skin of T.pahisfris, the large
water-newt, forms a beautiful opaque object,
showing the loose capillary network, which

TROCHAMMINA.

[ 784 ]

TRYPANOSOMA.

contrasts well with the brilliantly mottled
skin.

BiBL. Bell, British Reptiles.

TROCHAM'MINA, Parker and Jones.—
A variable geuiis of Arenaceous Foramini-
fera, very near Lituola ; shell opaque, sandy,
smooth ; moniliform, serpentine, folded,
discoidal, or subnautUoid and rotalioid ;
segmentation mostly obsolete except in the
last. Very many species or varieties, recent
and fossil. The discoidal forms constitute
Reuss's Ammodiscus. Tr. incerta, PI. 28.
fig. 14.

BiBL. Parker and Jones, Q. J, Geol. Soc,
xvi. 304 ; Ann. N. H. 4. iv. 386 ; Carpenter,
For. 141.

TROOHIL'IA, Dnj.— A genus of Hypo-
trichous Infusoria, family Ervilina.

Char. Body irregularly oval, narrower in
front, where there are some ciHa ; carapace
obliquely furrowed, slightly twisted, and
terminated behind by a moveable pedicle.

T. sigmoides (PI. 32. fig. 13) ; fig. 12 re-
presents the animal undergoing transverse
division ; marine. Two otlier species.

TROMBIDI'NA.— A family of Acarina.

Char. Palpi vAth the last joint obtuse,
the last but one unguicidate, the second
very large ; legs for walking, with two
claAvs ; eyes usually latero-anterior.

Principal genera : Anystis, Cheyletus, Me-
gamerus, Pachygnathus, Haphignathxis ,
Rhyticholophus, Smaris, Tetranychits, and
Tromhidium.

TROMBIDTUM, Latr.— A genus of
Trombidina (Arachnida).

Char. Palpi large, free ; mandibles un-
guiculate ; body turgid, bearing the four
posterior legs, and an anterior narroAv
moveable prominence, upon which the eyes,
the four anterior legs, and the mouth are
situated ; anterior legs longest ; legs seven-
jointed.

The species are nimierous, and not well
characterized.

T. phalangii (PI. (J. fig. 37). Body sub-
triangular, angles obtuse ; of a velvety ap-
pearance, from the presence of numerous
plumose hairs ; eyes two, placed upon auri-
cular appendages.

An external parasite of Phalangium (the
harvest-spider) and insects, at least in its
early hexapodous stage.

T. eliDtgatum. Crimson ; eyes approxi-
mate. Found under stones.

T. cinereum (PI. 6. fig. 40) (Rhynchoh-
phits ciner., l^ug.). Body with brown and
greyish-white spots ; hairs spathidate ; eyes

two on each side. Length 1-12". Found
in ditches amongst plonts and stones.

T. autumnale (PI. 6. fig. 38) (Leptus au-
tumn.). The harvest-bug. This well-
known arachnidan insinuates itself into the
human skin in autumn, causing troublesome
irritation. It is found ou plants and the
stubble of corn-fields, and may easily be
caught by tying a white pocket-hauclker-
chief around the legs, and walking through
stubble-fields. The young form with six
legs is most frequent^ met with.

T. aurantiacum, on the black \iQ?m- Aphis.
Other species.

T. {Atoma) parasiticum, on the house-fly.
Other species.

BiBL. Duges, Ann. Sc. N. 2. i. 36 ; Ger-
vais, Walck. Apteres, iii. 178 ; Johnston,
Tr. Berwick. Nat. Club, 1847, 221 ; Koch,
Deutschl. Crust. Myriap. i>;c. : Murray, Ee.
Ent. 128.

TRUNCATULI'NA, D'Orb.— A sub-
genus of Planorhtdina. Shell discoidal,
plano-convex, thick or thin, lobular or neat,
adherent by the flat face ; orifice slit-like,
slightly apparent above and continued be-
neath, along tlie line of suture, as far as the
second or third chambers.

Man)' recent and fossil species. PI. (Tr.)
lohatula (PL 24. fig. 9); very common,
attached to sea-weeds.

BiBL. Williamson, Rec. For. 60 ; Car-
penter, Foram. 207 ; Parker & Jones, Phil.
Trans, civ. 381.

TRYBLIONEL'LA, Smith.— A genus of
Diatomacese.

Char, Frustules free, linear or elliptical
in front view ; valves plane, with parallel
transverse (tubular ?) strife, and submarginal
or obsolete alfe.

In some a median line is present, in
others not. The, alfe are not marginal, as
in Surirella, but arise from the surface of
the valves, as shown by the diagram of a
transverse section in PI. 17. fig. 32.

T.sctdellum (PL 17. fig. 30). Valves
elliptical, with a median longitudinal line;
alae very short ; striae faint ; marine ; length
1-140".

T. gracilis (PL 17. fig. 31). Frustules
linear, narrowed at the ends ; valves linear,
acuminate, strite coarse ; alje distinct ; fresh
and brackish water ; length 1-200".

Four other species.

BiBL. Smith, Brit. Diatom, i. 35; Rabenh.
Alg. i. 347.

TRYPANOSO'MA, Gruby.— A genus
of Flagellate Infusoria. Free, compressed ;

TUBER.

[ 785 ]

TUBERCULAKIA.

one side thin, undulating, frill-like ; ante-
riorly produced into a long ilagellate appen-
dage ; no nioulh.

T. sa>i(/ id Ill's, in frog's blood, length
1-600"; f. Eberfhi, in the intestines of
poultry. (Grubv, Covipt. Rend. 1843 ; Kent,
Inf. 2l8.^

"TUBER, Mich. See Tuberacei.

TUBERA'CEI.— A family of Ascomyce-
tous Fungi, growing underground or upon
the siu'face, of more or less round form, and
solid, fleshy texture, excavated with sinuous
cavities liied by asci containing usually
four or eight spores, elegantly reticidated
or spinulose (figs. 768-770). The internal

Fig. 768.

Choiromyces leonis.

Fig. 768. A peridium. Nat. size.
Fig. 769. An ascus with spores. Magnified 400 dia-
meters.
Fig. 770. Vertical section of a peridium.

substance either dries and grows hard, or
falls into a floccident powder with age.

Tuber cibarium is the common truffle.
Sections of the marbled internal substance
show this to be composed of interlacing
branched filaments, forming fleshy convo-
lutions, between which serpentine cavities
are alternately excavated ; branches of the
filaments free at the sm-face of the lacunae
bear spherical sacs {asci), each containing
four globular spores of yellow-brown colour,
having an elegantly reticulated outer coat.
Wlien the spores germinate, they produce
a subterraneous cottony myceUum, which
after a time presents villous nodides, in the

interior of which the peridia are developed ;
as these advance, the villous coats gradually
vanish, together with the mycelial structure,
and the mature peridia appear free, either
a little beneath (Tuber cibarium) or upon
the surface {T. album) of the soil (see also
Elaphomyces).

BiBL. Berk. Br. Fl. ii. pt. 2. 227; Tulasne,
Ann. Sc. Nat. 2. xvi. o ; Monog. Fumj. Hij-
po(jcBi, 1851 ; Ann, N. H. 2. viii. 19 ; Les-
piault, Ann. Sc. Nat. 3. ii. 316 ; Vittadini,
Monog. 2\iber. ; Monog. Lycopocl., Mem.
Turin{Acad. 2. v. 145.

TUBERCLE or Tubercitlar jiatter.
— Tubercle consists of lymphatic corpuscles
contained in the meshes of a very delicate
reticulum, or a transparent homogeneous
tissue (PL 38. fig. 8). The cells vai-j^ in
size, and many contain a small distinct
nucleus. In addition to these, there are a
few larger cells containing two or even three
nuclei. The nucleated cells are exceedingly
destructible, so that often more fi'ee nuclei
than ceUs are visible. In most cases the
tubercle appears to consist entirely of closely
crowded nuclei or so-called tubercle-cor-
puscles (PI. 38. fig. 9 a), about 1-5000 to
1-4000" in size, oblong-angular, and un-
affected or simply rendered paler by acetic
acid (fig. 9 b).

Tubercle appears to originate most fre-
quently fi'om the tissue which surrounds the
small arteries in every situation, constituting
the lymphatic sheaths. The small cells in
this situation multiply at separate centres,
and thus miliary nodules are produced
aroimd the vessel ; and as they gradually de-
velope, they compress the vessel, and may
finally occlude it. Tubercle invariably
imdergoes a retrogressive change ; this com-
mences in the centi'e of the grauidations,
and consists in the atrophy and incomplete
fatty metamorphosis of the closely crowded
cellidar elements, constituting what is
termed caseation. The translucent and grey
granulations thus become opaque and yel-
lowish, the yellow tubercle being merely a
stage of the grey granulation. The caseous
tubercle subsequently softens, or may gra-
dually dry up into a firm cheesy mass, which
becomes ultimately calcified.

BiBL. Green, Path. Anat. 1871, 145;
Rindfleisch, Path. Hist. 1878.

TUBEROULA 'RIA, Tode.— A supposed
genus of Stilbacei (Hyphomycetous Fungi),
but apparently only preparatory forms of
Sphseriaceous Fungi. T. vulgaris is a state
of Nectria (Sphceria) cinnabarina ;' it is ex-

3e

TUBICLAVA.

[ 786 ]

TUBURCINIA.

tremely common in autumn and winter, on
dead sticks, damp wooden palings, stumps,
&c., forming scarlet-orange rounded nodules,
or irregular fleshy masses, sometimes more
or less stipitate, the surface at a certain stage
exhibiting the ends of the filaments termi-
nating in chains of cells breaking up into a
pulverulent substance. These cells are pro-
bably the couidia of the Nectri<2.

TUBICLA'VA, Allman.— A genus of
Athecate Hydroid Zoophytes.

Char. Stems erect, simple or branched,
arising from a creeping stolon ; polypes cla-
viform, with scattered filiform tentacles.
Reproduction by means of fixed sporosacs
in clusters on the body of the polype, behind
the posterior tentacle, or on very short stems
developed on the creeping base.

BiBL. Hincks, Hyd. Zooph. 10 ; Allman,
Ann. N. K. 3. xi. 9.

TUBICOLA'RIA, Ehr.— A genus of
Rotatoria, fam. Flosculariaea.

Char. No eye-spot ; disk f our-lobed ; stalk
long, contained in a transparent gelatinous
sheath. T, najas, jaws with four teeth ;
on Lemna. (Elu'enberg, Infus. ; Pritchard,
Inf.)

TU'BIFEX, Lamk.— A genus of Aunu-
lata, order Setigera.

Char. Body filiform, attenuated at the
ends, pellucid, with four rows of setae — two
dorsal and two ventral.

The worms live and burrow in the mud of
stagnant pools or the still parts of rivers,
giving it a bright-red appearance. When
the water or mud is disturbed, the red
patches instantly disappear, from the re-
traction of the animals. Length from 1-5
to 3-4" or more.

They are transparent, and show well tbe
alimentarj^ canal, with its peristaltic actions,
and the cilia lining it, the blood-vessels and
their movements, with the loops bathed
in the chylaqiieous liquid, and the coiled
water- (respiratory or I'enal) vessels with
their cilia.

BiBL. Schmidt, MiUlcr''s Archie, 1846,
406; Duges, Ann. Sc. Nat. 2. xv. 319;
Johnston, Ann.N.H. 1845, xvi. 443; Lan-
kester, Qu. Mic. Jn. 1871, 180.

TUBULA'RIA, Linn.— A genus of
Hydroid Zoophytes, family Tubulariid^.

BiBL. SeeTuBUL^VKIIDJE.

TUBULA'RllD/E.— A family of Athe-
cate Hydroid Zoophytes.

Char. Polypes fiask-shaped, with two sets
of filiform tentacles, one oral, the other near
the base.

Tubularia. Stem twisted, branched or
unbranched ; tentacles fihf orm in two rows ;
egg-germs or gonophores on short footstalks,
clustered at the bases of the lower tentacles.

Corymorpha. Partly enclosed; polypidom
short, thin, membranous, swollen at the base,
which is immersed in the sand ; polype
single, head club-shaped, encircled at the
base by long filiform tentacles, and a circle
of short ones around the tip.

-Ectopleura. With free medusiform sexual
buds.

BiBL. Hincks, Hijd. Zooph. 114; Lister,
Phil. Tr. 1834 ; Johnston, Br. Zooph. 48 ;
Mummerv, Qu. Micr. Jn. 1853, 28; Wright,
Ed. Neto Phil. Jn. 1858, 113; Allman,
Ann. N. Hist. July 1859, and July 1864 ;
Van Beneden, Ttibulmres.

TUBULIP'ORA, Lam.— A genus of In-
f undibulate Cyclostomatous Polyzoa, of the
family Tubuliporidae.

Three British species ; some of them
common upon shells, sea-weeds, &c.

PL 41. fig. 30 represents a species (not
British).

BiBL. Johnston, Br. Zooph. 266 ; Hincks,
Poh/z. 442.

TUBULIPOR'ID^.— A family of lufun-
dibulate Cyclostomatous Polyzoa.

Char. Polypidom calcareous, massive,
circular, lobed or divided dichotomously ;
cells long, tubular, with a round, prominent,
unconstricted orifice. Genera :

Tubidipora. Wart-like, with a defined
base ; cells suberect, aggregated or in im-
perfect rows, more or less fi'ee at the end.

Diastopora. Incrusting, undefined; cells
alternate, tubular, horizontal, immersed,
with a raised circular orifice.

Idmonea. Divided dichotomously, erect ;
cells on one side, tubulai-, in transverse
rows, divided iiito two sets by a median
longitudinal line.

Piistidipora. Erect, cylindrical ; cells
semi-immersed, on all sides, orifices pro-
minent.

Alecto. Creeping, adherent, irregidarly
branched ; cells horizontal, in one or more
rows, their ends free.

BiBL. Johnston, Br. Zooph. 264 ; Gosse,
Mar. Zool. ii. 7.

TUBURCIN'IA, Fries.— A genus of
Ustilaginei (Hypodermous Fungi J, occur-
ring in vegetable tissues.

T. scabies produces the disease called
scab in potatoes ; T. tricntalis occm-s on
leaves of Trientalis Etiropa'a ; conidia are
produced on the miderside of the leaves.

TUMOURS.

[ 787 ]

TUMOURS.

BiBL. Berk. & Br. Ann. N. H. 2. v. 464 ;
Cooke, Handb. 516 ; De Bary & Worouin,
Beit. V. pis. 1-3.

TUMOURS. — Non-inflammatory new
formations. Under this head we .shall
make a few remarks upon some of the more
interestino' elements ot certain tumours and
other morbid growths.

Sarcoma. The tumom's included under
this name, comprise the fibro-plastic, fibro-
nucleated, recurrent fibroid, and the myeloid.
They consist of comioctive tissue, i-etaining
more or less the embryonic type ; and the
varieties depend upon the size and form of
the cells, and the nature of the intercellular
substance. The cells are either round,
fusiform, or myeloid — larger cells containing
many nuclei or secondary cells. The inter-
cellular substance is scanty, homogeneous,
granular, or fibrillated.

Fibrous tumours consist of fidly developed
connective tissue. The fibres are sometimes
iii-m and dense, at others lax. The cells or
coimective-tissue corpuscles are very few in
number, and usually only become visible on
the application of acetic acid. They are
often minute spindle-shaped, fusiform, or
stellate bodies, the latter having processes
of varying length, which communicate with
those from neighbouring cells.

Gummata are new formations, consisting
of an incompletely organized granulation
tissue. They soon undergo retrogressive
changes; hence the growth is idtimately
made up of atrophied, degenerated, and
broken-down cell products, imbedded in an
incompletely fibrillated tissue.

Mifxomata consist of a ti'anslucent and
succulent connective or mucous tissue, the
intercelhdar substance of which yields
mucine. They are of a peculiar soft gelatini-
form consistence, and of a pale greyish or
reddish-white colour'. On scraping the cut
surface they yield a tenacious mucilaginous
liquid, in which may be seen the cellular
elements. The cells are angidar and stel-
late, with long anastomosing prolongations
and trabeculse ; others are isolated, fusiform,
oval, or spherical, with one or two nuclei.

Lipomata. Fatty tumours resemble adi-
pose tissue, and consist of cells containing
fat united by a variable quantity of connec-
tive tissue.

The Enchondromata and Osteomata con-
sist of cartilage and bone respectively ; and
the Lymphomata are new formations con-
sisting of lymphatic, or, as it is usually
termed, adenoid tissue.

The Pa^nllomata, such as warts, horny
growths, polypi, originate from the skin
and mucous membranes, of the tissues of
which they may be called exaggerations.
The adenomata, or tumours of glands, are
new formations of gland tissue. They
resemble the racemose glands, and consist
of small grouped saccules or tubes filled
with squamous or cylindrical epithelium-
cells.

The carcinomata, or cancers, consist of
cells of an epithelial type, without any
intercellular substance, gTouped together
irregularly within the alveoli of a fibrous
stroma. There are four varieties — scirrhus,
encephaloid, epithelioma, and colloid. These,
although all possessing the same general
characters, present certain structural dif-
ferences which serve to distinguish them.
The cells are comparatively large, varying
considerably in diameter, of a roimded,
oblong, or ovate form, usually in no definite
order, in the intervals of the fibres (PL 38.
figs. 11 & 12), although sometimes in the
ineshes formed by the aggregation of the
fibres into loose bundles (fig. 17).

The interspaces of the cells and fibres are
occupied by a pale yellowish or colom'less
liquid ; and the cells are so loosely imbedded
in the fibrous basis, that on scraping the
surface of a section of a cancer, uiuuerous
cells are found in the jiuce thus obtained.

The number of fibres present varies accord-
ing to the stage or development of the
cancer. In hard or schirrous cancer, they
predominate, the cells being few ; while in
soft, encephaloid, or medullary cancer they
are scanty, the cells being very abundant ;
globules of fat usually aboimd in the latter
forms.

Other varieties of cancer have received
special names. Thus, when the capillaries
are very numerous and distended, extrava-
sated blood being also frequently present,
we have fungus hfematodes ; when the
fibres are grouped into bundles, forming
marked areolae, filled with a gelatinous
substance, we have colloid or gelatiniform
cancer (PI. 38. fig. 18) ; again, when the
cancer cells abound in pigment, we have
melanotic cancers.

In epithelial caucea*, or epithelioma, the
general arrangement of the elements is not
strikingly altered, but the papiDae of the
skin are hypertrophied, the epithelial cells
more numerous than natural, sometimes
containing many nuclei or secondary cells,
and the intercellular juioe is more abundant.

3£ 2

TUNICATA.

[ 788 ]

TUNICATA.

The flattened epitlielial cells are also often
arranged around the papillae in the form of
concentric rings or nests, resembling fibres ;
but the cell-structure is at once rendered
e-^ident by the addition of solution of
potash.

In regard to cells generally, an insuper-
able difficulty is met vdih in discovering
the exponent of their power, as it might be
temied ; thus the embryonic cells or cor-
puscles in an early stage are undistinguish-
able from each other, yet some grow into
fibres of connective tissue, others into
nerve-tubes, &c. Chemistry lends no aid
here, and the difficulty will probably ever
remain.

In the examination of tumom's and other
morbid g:i'owths, sections should be made
with a Valentin's knife, the elements being-
first observed in water, and then in the
natm-al fiiud. The sections and elements
are best preserved in water.

BiBL. Paget, Tumours and Surgiccd Por-
tJioloyy ; Bennett, on Cancer, and Ed. Mn.
Jn. vii. & viii. ; Redfern, ibid. xi. ; and the
Tr. Pathol. Soc, passim ; Green, Path.
Anatomy ; Rindfleisch, Path. Gewehel.

TUNiCA'TA.— A class of Animals, be-
longing to the Invertebrate subkingdom Mol-
lusca.

Char. Marine ; often microscopic ; bodies
single, social, or aggregate ; acephalous ;
enclosed in an elastic tunic with two orifices,
one oral and branchial, the other anal
or cloacal ; a large atrial system, the
pharynx commimicatiug with it by bran-
chial slits ; respiration branchial, branchife
phar}Tigeal ; nervous system a ganglion ;
circidation effected by a tubular heart, with
vessels, the current of blood varying in di-
rection ; hermaplu'odite ; evolution accom-
panied by metamorphosis, or following the
law of alternation of generations (PI. 18.
figs. 10 & 20).

The smaller Tunicata are commonly found
aggregate, and investing rocks, stones, and
shells ; some are adherent to seaweeds, &c.,
a few are free ; many are common on the
sea-shore.

The body is sac-shaped or elongate, some-
times slightly constricted so as to exhibit a
thorax, abdomen, and a posterior portion or
postabdonien. The outer coat, test or
tunic, is cartilaginous, leathery, gelatinous,
or membranous ; and consists partly of cel-
lulose, often containing calcareous spicula.
Within this is another coat, the mantle,
usually adhering to the former at the orifices

only, and containing numerous muscidar
fibres. The oral orifice (PI. 18. fig. 10, a),
or opening of the usually dilated pharynx
or branchial cavity, within wliich is placed
the branchial apparatus (6), leads to the
mouth. This is slit-like, and leads into a
narrow oesophagus; to this succeeds an
expanded stomach (/), which terminates
in a longish intestine with a haemal curve
(i), and ends at the base of the cloaca
{{*), which opens externally at the atrial
orifice. Within the oral orifice, at the com-
mencement of the branchial cavity, is a ring
of rudimentary tentacles.

The branchial apparatus in the pharynx
(fig. 10, h) consists of numerous cross bars,
«ith slit-like openings between them ; these
are ciliated, and copiously supplied with
networks of blood-vessels. The slits open
into the atrial system. The current excited
by the cilia draws the water through the
oral orifice into the pharynx, where it tra-
verses the openings, flowing outwards to
collect in the cloaca, from which it is ex-
pelled through the atrial orifice. In some
of the larger Tunicata^ the branchial appa-
ratus is stra]^)-shaped, and traverses the bodj'
obliquely.

Tlie heart {h) is a spindle-shaped sac,
enclosed in a pericardium (p), and situated
near the base of the body, the principal
vessels running on the dorsal and ventral
surface of the branchial aj^paratus. The
current of blood varies in direction, being at
one time expelled from one end of the
heart, at others from the other. In those
Tuuicata which are connected by a common
tube, the blood passes freely from one to
the other.

The nervous system consists of a single
ganglion (fig. 10, g), situated between the
two orifices, and giving oft' its principal
branches to the branchial sac and the ali-
mentary canal. In some an eye is present,
resembling the compound eye of the Arti-
culata, and with a reddish pigment.

Moreover an auditory capsule has been
noticed in some genera.

The liver (/J consists either of a dark
glandular layer lining the alimentary canal,
or of distinct glandular ctieca.

The Tunicata are reproduced by gemma-
tion, by sexual organs, and by intermediate
generations.

The testis (/) and ovaiy {o) are usually
strap-shaped organs, either adherent to the
alimentary canal, or situ.ated in the poste-
rior part of the body j the former has a long

TURBELLARIA.

[ 789 ]

TYMrANIS.

spermatic duct (d), whicli opens into the
clo.ica, into ■which also the ova or larvfe are
discharged, to escape by the posterior orifice.
The larvfe often resemble at first tadpoles
with three anterior sucker-like organs, by
means of which they adhere to foreign
bodies to complete their development, the
tail gradually disappearing. In Appendicu-
laria the larval form persists through life.

The larval caudal appendage lias been
shown to have a rod-like body, which has
been compared to the chorda dorsalis of
Vertebrata.

In the large free Tunicata, the inter-
mediate generations are united into long-
chains, the final product being a sexual
individual ; but into the further structure
of these curious beings we have no space
to enter.

Synopsis of the Families.

* Attached; mantle and test united only at
the orijices.

BoTRYLLiDJE. Bodies united into sys-
tems.

Clavelinidje. Bodies distinct, but
connected by a common root-thread.

AsciDiAD^. Bodies unconnected.

** Free ; mantle and test united throughout.

Pelon^ad^. Orifices near together.
Salpidje. Orifices at opposite ends.

BiBL. M. -Edwards, Ascid. Comp., and
3Iem. de VInstitut, 1842 ; Forbes and Han-
lev, Br. Moll. i. 1; Siebold, VeryLAn. 234;
Lister, P/iiV. 7;-. 1834; Huxley, Com2i.An.;
Rupert Jones, Todds Cycloj)., Art. Tunicata;
Allman, Qu. Mic. Jn. vii. 86 ; Gegenbaur,
Vergl. An. ; Nicholson, Zool. 363.

See AppEXDICUI/ABIA, BoXBYLLIDiE,
Clavelinid^, (fee.

TURBELLA'EIA.— An order of Annu-
lata.

TURBINEL'LA, Schultze.— A genus of
Ichthvdine Rotatoria.

BiBL. Schultze, Midler's Archiv, 1853,
241 ; Pritchard, Inf. 381.

TURMERIC. See Curcuma.

TUR'RIS, Lesson. — A genus of Athecate
Hydroida, family Clavid?e.

Char. Stems short, rooted, bearing the
polypes on their summits ; polypes clavi-
form, with scattered filiform tentacles. T.
ne</leitn, in the Solent, Ilfracombe, kc.
(liincks, Hyd. Z<joph. 13.)

TYD.EUS, Koch.— A genus of Trombi-
dina (Acarina). Transverse line present ;

no eyes ; legs six-jointed. T. mutahilis,
very minute, on damp earth or moss. (Koch,
Uebers.; Mm-ray, Fc. Fnt. 120.)

TY'PHOID CELLS.— In typhoid fever
certain special uninuclear cells are formed,
which contain more protoplasm and are
larger than lymph-cells, pus-corpuscles, and
white blood-corpuscles ; these assume an
irregular and often polygonal form. De-
generative changes speedily commence, and
the cells break up, mostly by fatty meta-
morphosis, into oily debris capable of re-
absorption. The cells are found not only
in the intestinal structures, but also in other
organs ; forming medullary masses on the
pleural surface, and inside the sarcolemma of
muscles.

BiBL. Rindfleisch, Path. Geweb. 317.

TYM'PANIS, Fr.— A genus of Phaci-
diacei (Ascomycetous Fungi), consisting of
horny bodies growing on branches of trees,
breaking out through the bark. T. con-
spersa (fig. 771) grows upon Rosaceous

Fig. 771.

Fig. 772.

Tympanis conspersa.

A collection of perithecia, more or less mature, burst-
ing through the bark. Magn. 10 diams.

trees, T. saliyna on
the privet. In the
former the perithecia
are collected in tufts ;
they are first closed,
afterwards opening
into cups, the disk of
which is occupied by
the hymenium, bear-
ing long and broad
asci containing nume-
rous spores, and some-
times also septate Vertical section through
■ 1 • ij. apieceoi tneabove.passing

Stylospores SUUulta- through some of the open

neou.sly. In T. sahyna cup-like perithecia.

the perithecia occur Magnified 20 diameters.

only two to four to-
gether. Spermoyonia exist (which are oblong
or conical bodies) intermixed with the peri-
thecia, perforated by a terminal pore (re-
sembling perithecia of Sphceria) ; these are
lined with delicate branched filaments bear-
ing minute coi-puscles (spermatia), which

TYPHLINA.

[ 790 ]

ULVACE^.

■when mature escape from the pore in a
tencbil (as in Ci/tisjwra) if moistened or
pressed (see also Cenangium).

BiBL. Berk. £r. Fl. ii. pt. 2. 210 ; Ann.
N. H. 2. vii. 185 ; Hook. Jn. Bof. iii. 322 ;
Tulasne, Ann. Sc. Nat. 3. xx. 143, pi. 16.
figs. 15, 16 ; Fries, Sutn. Veg. 399 ; Gre-
yille, Crypt. Fl. pi. 335.

TYPH'LINA, Ehr.— An imperfectly ex-
amined genus of Eotatoria, of the family
PhUodinaja. T. viridis (Pi. 44. fig-. 33).
Found in Egypt. (Ehrenberg, Inf. 483.)

TYROG'LYPHUS. See Acarus.

TYUO'SINE. — This substance is gene-
rally found associated with leucine. It
forms silky-white needles, often in stellate
groups, difficultly soluble in water, and en-
tirely insoluble in alcohol and ether. When
warmed with sulphuric acid, and perchloride
of iron is added, it is rendered violet. The
little white grains found upon anatomical
preparations preserved in spirit consist of
tyrosine. (Hoppe-Seyler, Anah/se Chim, ;
¥vej,mst.51.)

U.

U'LOTHRIX. — A genus of Confervacese
(Couferyoid Algse), allied to Draparnaklin
and Stiyeoclonium. They consist of un-
branched filaments, adhering loosely toge-
ther to form a mucous stratum, growing
upon stones &c. in fresh water. The fila-
ments are composed of short hyaline cells
(PI. 9. fig. 6), the green contents of which
are at first granular, adhering to the waUs
(a), then contracted into transverse bands
(h). Contractile vesicles have been ob-
served in the cells of some species. Ac-
cording to recent observations, macrospores
with four cilia occur singly or in twos,
in certain cells ; while in others, numerous
biciliated microspores are formed, which
conjugate and produce resting spores ; these
again give rise to zoospores, from which
new filaments arise.

U. zoyiuta. Filaments 1-9G0" in diame-
ter, joints about as long {Lynghya zon.,
Hass. pi. 59. figs. 2, 3, & 6).

U.^jectmalis. Filaments 1-1800" to 1-9G0"
in diameter, joints half or a fourth the
length; fertile cells swollen (Hass. pi. 00.
figs. 1-5).

U. crispa. Filaments very long, 1-600" in
diameter, joints half or a third as long {Con-
ferva hico'hr, Enq. Hot. p. 2288).

_ U.floccosa. Fiiaments 1-2100" to 1800" in
diameter, joints about as long {Lynghya
floccosa, Hass. pi. 60. figs. 1 & 2).

U.puncialis. Filaments 1-3000" to 1-2500"
in diameter, regularly torulose ; joints two
and a half times as long as broad {Lyngb.
jnmct., Hass. pi. 00. fig. 4 ; including per-
haps L. virescens and L. vermicularis) .

U. spedosa. Filaments 1-780" to 1-420"
in diameter, curled ; sterile joints half or a
third as long.

U. mucosa, Thuret (PI. 9. fig. 6). Pale
green or yellowish, slimy ; joints usually as
long as broad, sometimes shorter, 1-3000" in
diameter.

BiBL. Kiitzing, *S^. Alg. 345 ; Tab. Phyc.
ii. ; Hassall, Ah/. 219; Thuret, Ann. Sc. N.
3. xiv. 222, pi. 18 ; Rabenht. Alg. iii. 365 ;
Cramer, Bof. Zeit. 1871 ; Dodel, PringsheinCs
Jahrb. x. 417.

UL'VA, Linn. — A genus of Ulvacese
(Confervoid Algae), here taken in the sense
of Thuret. The plants are all marine, con-
sisting of broad, green, simple, or lobed,
membranous fronds, growing upon rocks
and stones. The cells are rounded-angular
(PI. 9. figs. 2 & 3), and are at fii-st filled
with amorphous green colouring-matter,
which subsequently becomes collected into
masses (a), ultimately converted into nu-
merous zoospores. Under the influence of
light, those soon " swarm " and break out
from the cells by a pore in the outer wall
(fig. 3 6). The emptied cells give a pale
colour to the parts of the frond where they
are situated. The zoospores appear in two
forms, some large and bearing four cilia
(fig. 3 c), others much smaller and pos-
sessed of only two cilia (fig. 2 b). The
fronds in which the latter occur are gene-
rally of a yellower colour. Thuret has seen
botii kinds germinate. As defined by that
author, the British species stand as fol-
lows : —

U. Lactuca, L. Frond broadly ovate or
oblong, 6 to 18" long, and several inches
wide.

i3. kdissima. Frond 3' or more long, 18"
or more wide ; found in the muddy water
at the entrance of harbours {PJiycoseris My-
riotrema, Kiitz. Sp. Alg.)= U. orbiculata.

U. Linza, L. Frond linear-lanceolate,
6 to 24" long, i to 1^" wide.

BiBL. Harvey, Mar. Alg. 216, pi. 25 B;
Thuret, Mem. Sue. Cherbourg, ii. ; Ann. Sc.
Nat. 3. xiv. 224, pi. 20 ; Greville, Harvey,
Kiitzing, Algce ; Kabenht. Fl. Eur. Alg. i.
316.

ULVA'CE/E.— A family of Confervoid
Algaj. Marino or freshwater Alga?, con-
sisting of membranous, expanded, saccate

ULVINA.

[ 791 ]

UREDINEJ^.

or tubular, sometimos filiform fronds, com-
posed of spherical or polygonal cells, united
together firmly into layers, either single or
double. Reproduced "by roundish spores
formed from the whole contents of cells, or
by ciliated zoospores formed in twos, fours,
or many in each cell.

Ulva. Frond plane, simple or lobed,
formed of a double layer of closely packed
cells, producing zoospores.

Enterojnorpha. Frond hollow, simple or
branched, of a single layer of closely packed
cells, forming a sac or tube ; with zoospores.

Monostroma. Frond flat or saccate, simple
or lacerate-lobed, forming a single layer of
cells scattered in a homogeneous membrane ;
with zoospores.

Prasiola. Fronds membranous, lacerate-
lobed, formed of a single layer of cells in
simple or compound lines, or in groups mul-
tiples of four. Spores formed from the
whole contents of the cells, motionless.

ScMzof/onium. Fronds filiform, dilated
here and there into flat ribands, containing
two or four rows of cells ; spores formed
from the whole contents, motionless.

See PKOTODERiiA and Schizomeeis.

ULVI'NA. See CRYPTOcocCACEiE.

UMBILIC A'EIA, Fee ( Gp-ophora,Ach.).
— A genus of Phyllodei (Lichenaceous li-
chens). U. jmstulata gi-ows on rocks in
various parts of Britain. It is remarkable
for the tubercles or hollow papillae occurring
on its surface. The apothecia are flat, at
first black, at length tuberculate. Sper
mogonia also occur
tubercles

in the form of little
containing a nucleus of densely
packed sterig-mata, enclosed by a thin black
rind. The species in which the disk of the
apothecia is concentrically plicate form the
proper Gyrcphorce of Ach. ; they occur on
momitain-rocks. Several other species,

BiBL. Hook. Br. Fl. ii. pt. 1. 223; Tu-
lasne, Ann. Sc. Nat. 3. xvii. 207, pi. 5. figs.
•5-12 ; Schserer, Enum. crit. 25 ; Leighton,
Lich. Fl. 142.

UMBONEL'LA =LEPnALiApt. (Hincks,
Pob/zoa, 31G).

UNILOCULI'NA, D'Orbigny.— A sub-
genus of Miliola.

Char. Shell regular, equilateral, globular;
chambers completely embracing, regularly
woimd round the axis, one only apparent,
this making a complete revolution around
the preceding; cavity simple ; ori/ice single,
with a tooth.

In the other genera of the family, each
chamber occupies only half the circumfer-

ence, whilst here it forms a complete circle.
One species, U. ImJica (PI. 23. fig. 2).
(D'Orb. For. Fos. Vien. 261.)

URATES. See Uric acid,

URCEOLA'RIA, Ach.— A genus of Par-
meliacese (Gymnocarpous Lichens), included
under rarmclia by Fries, but agreeing in
almost every particular with Lecanora.
U. scritposa, the commonest species, gi'ows
on heaths, walls, and rocks. The disk of
the apothecia is black, and the border
crenated. The spores are cellular or multi-
locular (PI. 37. fig. 17). The si^rmogouia
are scattered over the thallus, sometimes in
the outer wall of the (thallodal) border of
the apothecia ; they are veiy inconspicuous,
on accoimt of the light colour of their
ostiole.

BiBL. Hook. Br. Fl. ii. pt. 1. 175 ; Tu-
lasne, Ann. Sc. Nat. 3. xvii. 172, pi. 4. figs.
5-14 ; Schferer, Enum. crit. 85.

URCEOLARIA, J)ii].= Trichodina pt.
U. mitra=^T. mitra.

URE'A. — This substance occm'S normally
in the urine of man and the carnivora, in
small quantity in that of the herbivora ; also
in the amniotic liquid, and the vitreous and
aqueous humours of the eye. Pathologi-
cally, it. is found in the blood, dropsical
effasions, vomited liquids, and doubtfully in
the saliva, the bile, and perspiration.

When pure, it forms colourless four-sided
prisms, sometimes longitudinally striated,
and with one or two oblique terminal facets.
The crystals are readily soluble in water and
alcohol, but not in pure ether.

When nitric or oxalic acid is added to a
solution of urea, the nitrate or oxalate sepa-
rates in the crystalline form.

The nitrate of urea, when rapidly formed,
consists of irregularly aggi'egated scaly cvys,-
tals (PI. 13. fig. 18c); when more slowly
formed, rhombic or hexagonal plates, or
distinct prisms (fig. 18 «, b). The crystals
of the nitrate of soda (PI. 10. fig. 19) bear
some resemblance to those of the lU'ea salt.

The crystals of the oxalate of urea some-
what resemble those of the nitrate, the
rhombic formbeing evident.

BiBL. That of C^HEJiiSTRY, Animal.

UREDIN'E/E. — The genus Uredo is
shown by Tulasne to have no satisfactoiy
claim to a distinct existence, since the struc-
tures which have represented it appear to
be merely a form of tlie reproductive organs
common to a number of plants, wliicli, in
their most perfect state, represent the genera
Ihiccinia, Phragmidium, Uromyces, Sec.

ITREDINB^.

[ 792 j

UREDINE^.

Fig. 773.

These constitute the genera of the family
Uredinei.

Of the genus Phraf/midimn, P. buJbosuin
(Piiceinia ruhi, Schfer.) is a species com-
monly occurring on the leaves of brambles,
forming reddish, then orange, and finally
blackish rusty spots (fig. 773). The first
signs of reproductiTC organs appear in the
middle of the spots on the upper face of
the leaf, consisting of a few minute unilocu-
lar cavities {spermoyoma) excavated in the
leaf, with a little flat ostiole ; in these
occur ovate s})er-
matia (see ^ci-
dixtm), which are
accompanied by a
yellowish mucous
liquid, and are ex-
pelled with this in
the form of drops.
Subsequently to
this, the tlredo-
fruits are deve-
loped, mostly on
the lower face of
the leaf, at the back
of the sperm ogonia,
or more rarelj' on
the upper face, in a
circle around them.
They are pulvei'u-
leut patches (fig.
773), solitary or a few together ; and a ver-
tical section (fig. 774) shows them to con-
sist of paraphyses (fig. 775), and simple or
branched short filaments bearing globose
stylospores (fig. 776), which soon become
detached, and in ripening acquire an echi-
nate outer coat with numerous pores.

Fig. 774.

Fig. 776.

Leaf of bramble,
" Ureclo ruborum."
the nat. size.

with
Half

Vertical section of the same Uredo-fruit, with para-
physes and imperfect stylospores, Magn. 460 diams.

When these germinate, they produce merely
a long slightly branched filament. Finally
the perfect fruits (spores) appear on the
same, or in distinct sori (on the lower fiiee
of the leaf) iu the form represented in fig.

Fig. 775. Separate paraphyses.

Fig. 776. Detached pedicels with stylospores.

Magnified 460 diameters.

Vertical section of the sorus of " Uredo suaveolens,'
with immature stylospores. Magnified 460 diameters.

Eipe stylospores of the same, germinating.
Magnified 460 diameters.

Fig. 779.

Fig. 780.

Deformed styloepores, with the spinuloae coat deve-
loped. Magnified 460 diameters.

UREDINE.E.

[ 793 ]

URIC ACID.

565 (p. 594). The loculi of these have each
three or foui- pores iu the upper part of the
side-walls, whence emerge m geruiiuation
(in spring) short tubular filaments, which
soon divide into four cells, from each of
which arises a minute " sporidiimi " borne
on a pointed sterigmatous process.

Puccinia composiUtrum exhibits very simi-
lar phenomena ; its Uredo-hmt has been
described as TJredo suaveohns. Fig. 777
represents a vertical section through an im-
mature sorus of this ; fig. 778 some of the
stylospores detached and germinating ; the
outer spinulose coat is here fully developed,
and the tubular filaments are seen emerging
from the pores. The spores of the perfect
fruits of this genus ditfer from those of
rhragmidium in being bilocular, or, by abor-
tion, imilocular (see Puccinia).

In ^ciDiUM, Cystopus, and some other
genera, spermogonia and styhsporous fruits
( Uredo-fruits, Tulasne) have been observed,
in Cronarfimn, spermocionia are unknovra,
but the C-^;-efZo-fruit exists. In Podisoma
both s^iermogonia and Uredo-ivmts, are un-
known ; in both of these genera the perfect
fr'uits are placed on a fleshy columella or
ligula.

We subjoin Tulasne's synopsis of the fa-
mily ; but as his generic characters are too
long to transcribe, the typical species only
can be cited.

I. Albuginei, white or pale yeUow, hetero-

sporous.
Cystopus. Type, Uredo Candida.

II. ^cidinei, with a peridium, homoeo-

sporous.
Cceoma. Type, Uredo euonymi; U.

jnnguis.
j^cidimn. Type, ^c. cichoracearum ;

^. tussilaginis, ^. violarum.
Roestelia. Tj^pe, yfi". cancellatum.
Peridermium. Type, Per. pint.

III. Melampsorei, soUd, pulvinate, biform.
Melamjisora. Type, Uredo populiwi ;

U. caprcearum.
Coleosporkwi. Type, Uredo rhinantha-
cearum ; U. campanidce.

IV. Phragmidiacei, pulverulent, biform,
infuscate ; centre of the family.

Phragmidimn. T>-pes, Phragmiditmi

incrussatiim, with Uredo ruhorum ;

Puccinia potentillce, witli Uredo poten-

tillarum.
Tri})hragmium. Type, T. ulmurice.
Puccinia. T}"pe, Puccinia composita-

7-«?;i, with Ur. suaveolens ; P.graminis,

with Ur. linearis.

Uromyces. Type, Uredo Jicartce.

Pileolaria = Uromyces ?, which itself
may consist of species of Puccinia
with spores unilocular by abortion.

V. Piicciniei, fleshy, ligulate, or trcmel-

liform, naked and uniform in the
fruits ; the largest plants of the
family.

Podisoma. Type, P. jimiperi commu-
nis.

Gymnospo7'angium. Type, P. junipe-
rinum.

VI. Cronartici, peridiate, biform, ligulate ;
perhaps the most highly organized of
all the genera.

Cronartium. Type, Cr. asclepiadeum,
with Uredo vincetoxici ; C. pxeonice,
with Ur. piOionicB.

Genera cancelled by Tulasne : — Uredo,
Epitea, Podocystis, Trichobasis, Lecythea,
Physonema, Solenodonta.

Genera referred to Ustilaginei : — Usti-
lago, Tilletia, Thecaphora.

Doubtful UsTiJGAGiNEi : — Protomyces, Po-
lycystis, Testicuhiria.

BiBL. Berk. Br. Fl. ii. pt. 2. arts, ^cid.,
Puce, Uredo, 8,-c. ; Ann, N. H. i. 264, 2. v.
463 ; Tulasne, Ann. So. Nat. 3. \ii. 12, 4. ii.
77 ; Leveille, ib. 3. viii. 369 ; De Bary,
Brandpilze, 1853; Fries, Sum. Veg. 509;
Uuger, Exanth. Plant. ; and the Bibl. of
the Genera.

URIC ACID and URATES, or lithic
acid and lithates. — Uric acid may easily be
procured in small quantities from human
urine, by adding a few drops of dilute mu-
riatic acid, and setting the liquid aside for
some hours, when it subsides in crystals.
In larger quantity it may be obtained by
heating the excrement of serpents with ex-
cess of dilute solution of potash, until the
odoiu' of ammonia has disappeared, and fil-
tering the solution whilst hot into dilute
muriatic acid, when it falls in a colourless
state. Or the excrement may be digested,
without heat, with excess of strong sulphuric
acid, the mixture set aside that the impmi-
ties may subside, and subsequently poured
gradually into a large quantity of distilled
water.

It exists also iu the excrement of birds,
in the urine of MoUusca and Insecta, and of
all the Mammalia, -excepting those which
are herbivorous ; it has also been found in
the human blood, of which it is probably a
normal constituent in minute quantity, al-
though mostly secreted with the urine as
soon as formed.

URIC ACII).

[ 794 ] URINARY DEPOSITS.

Ill the natural state of solution in the
urine, uric acid exists combined with soda
and ammonia ; but it is frequently found as
an abnormal deposit in the human mine,
and is often precipitated after the secretion
has been evacuated, from the occurrence of
an acid fermentation. The crystals of the
free acid are sometimes also met -with in
the urine or excrement of the lower ani-
mals, as Insects, &c.

Uric acid is but little affected by water,
alcohol, acetic or muriatic acid, slowly so-
luble in solution of ammonia, but readily in
solution of potash, from which it is re-pre-
cipitated by a dilute acid.

The crystals belong to the right-rhombic
prismatic system.

Their various forms are represented in
PI. 12. figs. 1-10, and fig. l-'5. Those in fig. 1
are frequently met with as natural deposits
from human urine, although most of the
same forms, with those in fig. 15, are also
found in the artificially precipitated acid.
The most common and characteristic form
is the rhomb (a), the side view being linear
or rectangular. When the urine is strongly
acid, the crystals often appear striated from
the presence of linear fissures (c,d). Some-
times they are narrower and more elongate,
with a prismatic form (c). They are fre-
quently aggregated, and either fused into
twin crystals (/, ff), or form aigrettes or
tufts {h, I, m, n, oj. The other forms are
noticed in the description of the plate.

The crystals forming a natural deposit are
almost invariably coloured, from combining
with the colouring-matter of the urine ;
sometimes their colour is very brilliant
(fig. 4) ; they may also be coloured artifi-
cially by precipitation from a solution of
purpurate of ammonia (fig. 3), madder, &c.

The test for uric acid is the production of
the colour of purpurate of ammonia or mu-
rexide, whicli may be efiected by dissolving
the crystals or suspected substance in a
small quantity of dilute nitric acid, gently
evaporating the solution to dryness, and
adding a little ammonia to the residue, or
exposing it to the vapour of ammonia, when
the red colour becomes visible. But the
rhombic form, when present, with the action
of potash and dilute acid, Avould be suflicient
to distinguish this acid from most sub-
stances.

The formation of the crystals of uric acid
presents an interesting object for examina-
tion. A drop or two of solution of uric acid
in potash is first placed upon a slide and

covered with thin glass ; a little dilute mu-
riatic acid is then applied to the edge of
the liquid, or a drop of strong acetic acid
placed near its edge, so that the vapour may
be absorbed by the liquid. The latter soon
becomes turbid, from the formation of a pre-
cipitate of numerous molecules and granules.
If the turbid liquid be watched under the
microscope, a minute crystal will presently
be seen to form suddenly in some part of
the field. The molecules and granules then
slowly dissolve immediately around the crys-
tal, leaving this in the middle of a clear
space. The crystal now enlarges, and the
surrounding molecules gradually disappear,
until they at last entu'ely vanish from the
field. By careful inspection, it may easily
be seen that the crystal is not formed by
the coalescence of the precipitated molecules,
but is deposited from a state of solution.

Some crystals of uric acid polarize light
splendidly ; and some of the feathery crystals
(PI. 12. fig. 8e) possess considerable ana-
lytic power.

The forms of the crystals and ciystalline
groups of the urates are represented in PI.
12. figs. 11-14 ; they are not very charac-
teristic, and the aid of chemistry is requii-ed
for determining with certainty the com-
position of the respective crystals.

The urate of ammonia may be prepared
artificially by adding ammonia to a boiling
mixture of uric acid and water ; the urate of
lime by mixing urate of potash with chloride
of calcium ; the urate ol soda by di.^solving
uric acid in solution of soda ; and the urate
of magnesia by mixing solutions of sulphate
of magnesia and urate of potash.

The presence of an excess of lU'ic acid in
the blood is the chemical expression of
gout ; it leads to an abnormal precipitation
of urates in various parts of the body. In
cartilage the cells are the chief depositories
of the urates of soda and lime, and they form
the centres of the stellate bundles of crys-
tals by whicli the tissue is permeated.
The appearance of cartilage thus affected is
very characteristic ; and each cartilage cell
is surrounded by radiating tufts of crystals
Avliich uearlj' or quite touch the extremities
of other groups radiating from neighbouring
cells. See Urinary I)i:posits.

Bini-. Rindfleisch, Pff^//. Hisf. ii. 270;
and that of Ciiemistry, Animal.

URINARY DEPOSITS.— We shall give
here a list of the deposits most commonly
occurring in the human urine, with the re-
ferences to the plates in which they are

URINARY DEPOSITS.

[ 705 ]

UROCOCCUS.

represented, and the articles in which they
are described.

Since the publication of the important
paper by Vigla (L'Rvpenaice, 18^9), in
which most of these deposits were fu'st
illusti'ated, the use of the microscope has
constantly been called in to aid in their
detection. In regard to the pathological
indications aft'orded by their presence, upon
which we cannot enter, it may be remarked
that most of the deposits are formed after
the evacuation of the lu-ine.

Uric acid. PI. 12. ligs, 1, '2; and Urates,
figs. 11 c, d, e, 13 a, 14 a (Uric acid and
Urates).

Oxalate of lime. PI. 13. figs, 9, 10, 11,
12 (LniE, Salts of). The concretionary
forms of this salt (figs. 11, 12) are more
slowly acted upon by reagents than simple
crystals.

Ammotno-phosphate of mat/nesia. PI. 13.
figs. 1, 2, 3, 4 (Magnesia, Salts of).

Carbonate of lime. PI. 13. fig. 8 (LoiE,
Salts of).

Cystic oxide. PI. 13. fig. 5 (Cystic
oxide).

Blood-corpiiscles. PI. 49. fig. 21, espe-
cially the form fig. 21 e (Blood).

Mucous coiyuscles. PI. 1. fig. 6 (IVIouth,
p. 518).

Pus-corjmsclcs. PI. 38. figs. 4, 5 (Pus).

Spermatozoa. PI. 50. fig. 25 (Sperma-
tozoa). These are found in the urine of
the female for several days after intercourse ;
and we have detected them in the uterus
more than a fortnight after the same.

Sarcina ? PI. 7. fig. 5 (Sarcina).

Fungi. Penicillium (fig. 557, page 584 ;
PI. 26" fig. 15) and Torula (PI. 26. fig. 7).
The spores of Penicilliwn form the so-called
small organic globules.

Casts of the tiibuli uriniferi. The extreme
diameter of these is rather less than that of
the tubules ; but they are often much more
slender. They are cylindiical, generally
wavy, sometimes hollow, at others solid.
Some are very transparent, finely granular,
and are composed of fibrine ; others consist
entirely of, or contain imbedded in them,
renal epithelial cells, with or without glo-
bules of fat either free or within the cells ;
they sometimes also contain mucous and
pus-corpuscles, with blood-globules ; some
of the epithelial cells occasionally contain
lithates. The epithelium of the bladder
agrees essentially in structure with that
of the pelvis of the kidney.

Bebl. That of Chemistry, Animal]

Hoppe-Seylcr, Chim. jihi/s. ^-c. ; Schmidt,
Versuch. ^-c. ; Griifith, Urinary Deposits
and Med. Oaz. 1843.

URNATEL'LA, Leidy.— A genus of
freshwater Polyzoa.

Not yet found in Britain,

BiBL. Leidy, Pr. Ac. Philadelphia, v. Sc
vii. ; and AUman, Polyzoa, 117,

UR'NULA, Clap, et Lach.— A genus of
Actinophrnna (Rhizopoda).

Char. Slieath membranous and fixed to
other bodies. U. Episfylidis (PI. 52. fig. 15),
attached to the pedicle of Epistijlis j)lica-
iilis. (Clap, et Lach. Inf. 457.) "

UROCENTRI'NA. A family of CiUate
Infusoria.

BiBL. Clap, et Lach. Irif. 134.

UROCEN'TRUiM, Nitzsch.— A genus of
Peritrichous Infusoria, family Urocentrina.

Char. Free, no pedicle ; tail awl-sliaped ;
cilia absent from the body, but forming an
anterior crown ; mouth not spiral,

U. turbo (PI. 32. fig. 14). Body hyaline,
ovate, trilateral, tail one third the length of
the body. Freshwater ; length 1-430 to
1-290". (CI. & Lachm. Inf. 134 ; Kent, Inf.
641.)

UROCOCCUS, Hassall,— A genus of
Pakuellacese (Confervoid Algte), remarkable
for the peduncular processes formed by the
gelatinous coats of the cells. The cells are
invested by a gelatinous coat or membrane
(like that of Glceocapsa), which is ori-
ginally simple ; but new gelatinous layers
are successively produced on the immediate
surface of the cell-contents ; and as each new
one is formed the preceding layer is rup-
tured on one side and partially thrown off,
the cell with its new layer lying in the pre-
ceding layer as in a cup ; by the repetition
of this process the cup-like exuvifc accumu-
late, packed one within another so as to
form a peduncle, the structure of which may
be roughly compared to a pile of wooden
washing-bowls or tea-cups standing one in
another. When the cell-contents divide
into two portions, the peduncles bifurcate
(PI. 7. fig, 7). The sti-ise indicating the
successively shed coats are more or less di-
stinct in different species, and probably
in different conditions of the same. U.
flookerianus is represented in PL 7. fig. 7 :
U. insignis is veiy much larger; U. All-
nianni and U. cryptophila are much alike,
and neither presents the striae. A green
species is also described with the synonym
(erroneous ?) of Chlorococcum murale, Grev.
Reproduction unknown.

UROCYSTIS.

[ 796 ]

UROTRICHA.

BiBL. Hassall, Mar. Alg. 322, pi. 80;
Braun, Verjihujmig {Ray Soc. 1863, 178) ;
Rabenlit. Al{/. iii. 31.

UROCYS TIS. See Polycystis.

UROGLAUCINE. — This substance,
which was first detected by Heller, may be
obtained by evaporating human urine with
concentrated nitric acid (PL 13. fig. 20). Its
true nature is unknown ; but it is probably a
product of the decomposition of the colour-
ing-matter of the urine; it has perhaps
some relation with indigo.

BiBL. Heller, Archiv phys. Chemie und
Mikr. ; Lehmanu, Phys. Chem. ; Funke,
Atlas.

UROGLE'NA, Ehr.— A supposed genus
of Volvocineae (Coufervoid Alg^), consist-
ing of a family of zoospore-like individuals
arranged at the periphery of a membranous
sphere, as in Vol vox, but said to difter from
that genus in having only one cilium, and
a basal prolongation or tail running toward
the centre of the sphere. U. volvo.v forms a
sphere, 1-95" in diameter, with yellowish
bodies 1-1728" long, two lateral colour-
bands, exclusive of the tail, which is three
or four times as long. Inhabiting bog-pools.
Kent places it among the Flagellate In-
fusoria. (Ehr. Inf. 61; Kent, /??/. 414.)

UROLEP'TUS; Ehr.— A genus of Ilypo-
trichous Infusoria, family Colpodina ; ii'esh-
water.

Cha); Eye-spot absent; no tongue-like
process or proboscis ; a tail present.

U. jn-scis (PI. 32. fig. 15 a) = Oxyfricha
caudata, Duj. Body terete, subturbinate,
gradually narrowed behind into a tail ; in-
ternal granules gi-een; length 1-288 to
1-144".

U. lamella (PI. 32. fig. 156). Body de-
pressed, hyaline, linear-lanceolate, flat and
very slender; length 1-216". Other species.
(Ehrenberg, Inf. 358 ; Kent, Lif. 779.)

UROM'YCES, Lk.— A supposed genus
of Uredinei (Coniomycetous Fungi), perhaps
not properly separated from Puccinia, but
distinguished from the ordinary state of that
genus by the unilocular spores of the per-
fect fruit (see Uredinei and Puccinia).
The genus Pileolaria, Cast., does not appear
to difter from Tlromycvs in any essential
particular. The ZTyomycetes are rusts oc-
curring upon leaves, presenting at least two
forms of fructification (spermoyonia have
not yet been observed), viz. 1. Urcdo- fruit f,
consisting of stylosporos unaccompanied by
paraphyses, which have been described as
species of Trichohasis, Lev. ; and 2. the per-

fect fruit, resembling that of Puccinia, but
with unilocular spores, imaccompanied by
paraphyses. U. Jicarm, L^v. ( Tlredojl-
carice, Alb. & Schw.) is not uncommon
on Rauunculacefe, U. appendiculatus, Lk.
{Uredo appendicidosa, Berk.), on various
Leguminosse.

BiCL. Berk. Br. Fl. ii. pt. 2. 380, 382 ;
Tulasne, Ann. Sc. Nat. 4. ii. 145 & 185 ;
Leveille, ib, 3. viii. 370 ; De Bary, Brand-
pike, 33.

IJRONE'MA, Duj.— A genus of Holotri-
chous Infusoria.

U. marina (PI. 32. fig. 16). Body colour-
less, semitranspareut, nodular, and with
four or five faint longitudinal ribs ; mouth
ventral, with a trap-like velum ; marine ;
length 1-570".

BiBL. Duj. Inf. 392; Clap. «& Lach. Inf.
271 ; Kent, Inf. 546.

URONYCH'IA, Stein.— A genus of
H;s^otriclious Infusoria. Oval-oblong, with
a carapace, truncate in front, with a mem-
branous upper lip, with posterior hooks ;
mouth excavated, with a band-shaped un-
dulating membrane.

U. transfnqa = Plccsconia sadum, Duj.
Salt water," (Stein, Inf. ; Kent, Inf 797.)

UROP'ODA, Latr.— A genus of Arach-
nida, of the order Acarina and family Ga-
masea.

Char. Palpi and rostrum inferior ; dorsal
shield consisting of a single, broad, circular
or oval piece ; legs nearly equal ; body fre-
quently with a caducous anal peduncle.

U. vegetans (PI. 6. fig. 25j. Sixth joint
of legs longest. The peduncle forms a
horny filament, secreted from the .amis, and
serving to attach the body to Coleopterous
insects, of which this animal is the parasite,
although it is sometimes found under
stones. Four other species, most of them
doubtful.

BiBL. Duges, Ann. Sc. Nat. 2. ii. 29;
Gervais, Walck. Apt. 220.

UROSTY'LA, Ehr.— A genus of Ilypo-
trichous Infusoria, fam. Oxytrichiua.

Char. Body ciliated ; styles present in a
small cleft on the ventral sm'face ; no hooks.

U. yrandis (PI. 32. fig. 17). Semicyliu-
drical, subclavate, rounded at the ends,
slightlj' thickened in front; freshwater;
length 1-44 to 1-96". (Elir. Inf 309;
CI. & L. Inf 142 ; Kent, Inf. 797 .j

UROT'RICHA, CI. & Lachm.— A genus
of Ilolotrichous Infusoria, family Trache-
liua. Free, oyate, witli a long posterior
saltatory cirrus.

URTICA.

[ 797 ]

USTILAGO.

Two species ; freshwater. (CI. & Lachm.
Inf.SU; Kent, Inf. 504c.)

URTl'CA, L.— A genus to wliicli the

stingiug-nettle belongs (see Stings).

US'NEA, Aeh.— A genus of Ramalodei
(Lichenaceous Lichens), with a somewhat
crustaccous branched tliallus, bearing pel-
tate apothecia, which often have a ciliated
margin. U. harhata is common on park-
pales and old trees, U.florida andplicata in
similar situations, mostly in mountainous
regions. Tlie pendulous tibrillous thallus
and ciliated apothecia of U. harhata are
very characteristic.

BiBL. Hook. Br. Fl. ii. pt. 1. 2-30; Leigh-
ton, Lich. Fl. 75.

USTILAGIN E^E.— A family of Hypo-
dermous Fungi related to the Uredinei,
generally distinguished by their growing in
the interior of the organs (especially the
ovaries and anthers) of Flowering I'lants,
causing deformity, absorption of the internal
tissue, and its replacement by a pulverulent
substance cou.sisting of the spores of the
Fimgi. In the earlier stages, the infected
organ exhibits either a grumous mass, or
an interwoven filamentous mycelium, from
which acrogeuous spores arise ; finally the
mycelium disappears, and a dark-coloured
(ol'ten foetid) powder remains, composed
entirely of the spores, which are simple, or

Fig. 781.

Fig. 782.

Fig. 783.

Fig. 784.

Fig. 785.

Thecaphora deformans.

Compound spores, entire and broken up.

Magnified 460 diameters.

more rarely compound (figs. 784, 785), i. e.
several coherent within a common coat, at
length free (Kgs. 781-783), smooth or
unequallv echuiate or reticulated.

BiBL. iBerk.i?r. Fl. (art. Uredo) ; Tulasne,
Ann. Sc. Xat. 3. vii.
Bramlpilze ; Bauer

5, ii. 157 ; De Bary,
and Banks, CuHis^s

Pract. Obs. on Br. Grasses, 1805; Linger,
Exanthem. Plant. ; Fischer v. Waldheim,
Ustilat/mci.

UStlLA'GO, Fries.— A genus of Usti-
laginei (Hypodermous Fungi), forming

Fig. 786.

Fig.

r87.

Fig. 786. Ustilago Carbo, on oats. Nat. size.
Fig. 787. Ustilago Carbo, on barley. Nat. size.

smuts, infesting the ears of corn and other
grasses, the ovaries and anthers of other
Flowering Plants, and in some cases the
leaves and stems of plants. The interior of
the organ infested by them presents at
first a grumous-mucous whitish mass, which
grows at the expense of the tissue and juice
of the infested organ, and is finally con-
verted into a pidveruleut mass of simple
spores, mostly of deep colour, and with a
smooth, spiny or reticulated surface.

The species growing upon leaves and
stems occur on grasses, e. (/. U. lonr/issima
(Uredo lonc/issima, Sow.), 17. hj/podytes (Ur.
ki/podi/tes), and U. f/randis (or typlioides) ;
they form linear patches, ultimately con-
taining smooth black spores.

The greater number, however, occur in
the parts of flowers, especially of gi-asses —
Ust. Carho (Uredo segetum, Pers.), form-
ing the blight called smut of corn, com-
monly infesting wheat, oats (fig. 786), barley
(fig. 787), and other grasses, filling the ears
with a black powder of smooth spores,
about 1-5000" in diameter in corn, some-
times about twice as large in the varieties
attacking species of Bromus. The smut of

UTERIA.

[ 798 ]

UVELLA.

maize {U. maidis, fig. 788) has minutely
echinate spores, 1-2500" in diameter.

It is curious that when U. Anthe-
ranmi attacks a dioecious plant, as Lychnis
dioica, it causes the abortive stamens to be
developed, and then finds its place in the
uevs' anthers.

Sedges are infested by Ust. urceolarum
with dark-brown and Ust. oUvacea with
olive-colom-ed spores (Uredines, Br. Fl.)

Fig. 788.

Vortioii of a spike of Maize infested with Ustilatjo
maidis. Some of the lower grains perfect and mature:
above these, femah; flower with abortive ovaries. The
projeeting bodies are grains which have become de-
formed by the Ustilago developed within them.

Ust. caitJicrarum, growing in the anthers of
Caryophyllacese, has violet-coloured spores.
Many other species are described by Tulasne,
several of which have occurred in Britain.

BiBL. Tulasne, Atin. Sc. Nat. 3. vii. 73, 4.
ii. 157 ; Berk. Br. Fl. art. Uredo; Ann. N.
H. 2. V. 463.

UTE'RIA, Mich. See Thyrsopouklla.

UTERUS.— The substance of the uterus
consists of longitudinal, transverse, and

Fig. 789.

oblique unstriated muscular fibres, inter-
woven with imperfectly developed areolar
tissue resembling that in the stroma of the
ovary.

Three layers of muscular fibres are de-
scribed, but they are intimately connected.
Those in the cervix are principally trans-
verse or circular ; and immediately beneath
the mucous membrane at the mouth of
the uterus, the transverse fibres form a
sphincter.

The muscular fibres are
from 1-600 to 1-400" in
length, fusiform, with elon-
gate-oval nuclei, and very
difiicidtly separable on ac-
count of the large amount of
areolar tissue intermingled
with them.

The epitheliumis simple
and ciliated. The mucous
membrane of the body has
no papiUee, but here and
there some folds, and con-
tains numerous tubular or

uterine

glands

resembling

the Lieberkiihn's glands of
the intestines, their csecal
ends being simple, bifurcate,
or spiral, and consisting of
a basement-membrane with
cylinder-epithelium.

In the cervix are situated
glandular depressions of the ^
mucous meAbrane, " which ^^^l^ZT^^^Z
secrete a transparent tena- after parturition,

cioUS mucus ; some of these treated with acetic
, -I -I f , , aeicl. a, nuclei ;

are closed, and torm the y, globules of fat.

ovules of Naboth. Magnified

The lower third or half 350 diameters,
of the canal of the cernx
contains papillee covered with ciHated epi-
thelium.

During gestation the uterine elements,
especially the muscular fibres, as also the
vessels and probably the nerves, become
enlarged and more numerous, from new
formation (fig. 790).

All three of the coats of the veins of the
pregnant uterus contain muscular fibres.
After parturition, many of the muscular
fibres imdergo fatty degeneration, and be-
come absorbed (fig. 789).

BiBL. Kolliker, Mikr. An. ii. ; Chrobak,
StricJcer's Hist. iii.

UVEL'LA, Bory, Ehr.— A genus of
Flagellate Infusoria, fam. Monadina.

Char. Bodies without an eye-spot,

in^ELLA.

[ 799 ]

VALLISNEKIA.

Fi{?. 790.

U i

a I

Muscular elements from a uterus at five montha' ges-
tation, a, formative cells ; 6, young, c, fully developed
muscular fibres. Magnified 3o0 diameters,

movmo- by means of two flagelliform fila-
lueuts, aud aggregated into spherical revol-
ving clusters.

JJ. viresceiis (PI. 32. fig. 18). Bodies
ovate, rounded at each end, with two lateral
bright green bands. Diameter of clusters
1-288", length of bodies 1-2016" ; fresh-
water.

The life-cycle of a cercomonad. — One of
the Uvellce has been described by DaUinger
and Drysdale. When mature it multiplies
by fission for a period extending over from
two to eight days. It then becomes pecu-
liarly amoeboid ; two individuals coalesce,
.slowly increa.se in size, and become a sUghtly
distended cyst. The cyst bursts, and incal-
culable hosts of excessively minute sporides
are poured out, as if in a viscid fluid and
densely packed ; these are scattered, and
slowly enlarging, acquire flagella. They be-
come active, attain rapidly the parent form,
and once more increase by fission.

BiBL. Dallinger and Drvsdale, Mn. Mic.
Jn. 1873; Ehr. hif. 19;' Duj. Inf, 300;
Kent, Inf. 406.

UVICtERI'NA D'Orb.— a genus of hya-
line Foraminifera, near Poh/morphina, Shell
made up of three series of inflated chambers,
alternating irregularly on an elongate spire,
often ribbed ; orifice central, round, tubular,
and lipped. The triserial alternation passes
sometimes into a biserial and even a uni-
serial growth (Sar/rina, restricted). Um/e-
rina is world-wide in its distribution, and
goes back to the Middle Tertiary I'eriod.

U. pygmcsa (PI. 23. fig. 8).

BiBL. D'Orbigny, Ann. Sc. Nat. vii. 209 ;
Carpenter, For. 169 ; Parker & Jones, riiil.
Tr. clv. 363.

V.

VAGINIC'OLA, Lamarck.— A genus
of Peritrichous Infusoria, fani. Vorticellina.

Char. Bodies as in VorticeUa, single or
in pairs, in a membranous urceolate sessile
sheath.

V. crystallina (PI. 32. fig. 19) = Cofhurma
crystallina. Sheath crystalline, urceolate,
straight, internal granules green ; length
1-216".

Several species, salt and freshwater.

BiBL. Ehr. Inf. 295 ; Clap. & Each. Inf.
126.

_ VAGINULI'NA, D'Orb.— A Stichoste-
gian subgenus of Noclosarina, with oblique
chambers.

V. hadenensis, D'Orb. (PI. 23. fig. 35).

BiBL. Willia-mson,7<b?-«?«.21(Z>ento/zV?a) ;
Jones, Parker, aud Brady, Monoyr. For.
Crar/, 63.

VALKE'RIA, Flem.— A genus of In-
fundibidate Ctenostomatous Polyzoa, of the
family Vesicular iidse.

Char. Variou.sly branched ; cells oval,
irregidarly clustered ; eight tentacles, but
no gizzard.

V. cuscnta. Stem with subverticillate
branches ; cells in clusters or opposite pairs ;
on marine Algae, shells &c.

F. uva. Stem creeping, irregularly
branched ; cells scattered.

V.jyustulosa. ■ Dichotomous or alternately
branched ; cells clustered, imilateral.

V. tremella. Cells very small and slender.

BiBL. Johnst. Br. Zooph. 373 ; Gosse,
Mar. Zool. ii. 20; Hiucks, Poh/z. 551.

VALLISNETtIA, Mich.— An aquatic
genus of Angiospermous Flowering Plants,
belonging to the faniUy Hydrocharidacece.
V. sjnralis, a native of the South of Europe,
occurring wild also in North America, India,
&c., is commonly grown in jars for the sake

VALVULINA,

[ 800 ] VASCULAR BUNDLES.

of observing the Rotation in the leaves.
This plant is clicecious ; and the specimens
ordiuarilv found in cidtivatiou are the pistil-
late forms, which often produce flowers,
but the seeds, remaining unfertilized, never
ripen ; the plant increases rapidly, however,
by runners, if in a healthy condition. We
find it thrive well in any situation indoors
near a window and not exposed to frost ; but
it attains a far larger size in water kept at a
high temperatiu'e, as in Victo)-ia-t&nks in
Botanic Gardens. It is necessary, when
growing it in jars, not to keep too many or
too large snails in the water, as they destroy
the leaves. See Rotation.

VALVULI'NA,D'Orb.— A genus of Are-
naceous Foraminifera.

Tj^icaUy it has a triserial, three-sided,
pyramidal shell, with three chambers in a
turn of its spire and a valved or tongued
aperture. The trifacial compression disap-
pears in a common trochoid form, which
becomes scale-like and flat. If the cham-
bers fail to make a coil, an obliquely semi-
oval shell is produced, with a broad oblique
septal plane and a large valve, which bridges
over the crescentic aperture with bars. The
triangular form sometimes becomes Bulimi-
noid ; and often takes on a uniserial growth
{Clamdina, restricted), either cylindric, tri-
carinate, or five-angled. Numerous forms,
recent and fossO. V. austriaca (PI. 23. f. 20).

BiBL. Parker & Joues, Ann, N. H. 3. v.
467 ; Carpenter, Forani. 146 ; Brady, Carh.
For., Pal. Soc. 1876, 81.

VAMPYREIi'LA, Hckl.— A doubtful
genus of Radiolarian Rhizopoda. Body
red, rounded, without nucleus or contractile
vesicle, and with very slender pseudopodia.
These animals perforate the cells of Sin-
royyra and Gompho}i£)na,sm([ feed upon their
contents. In the encysted condition, thoy
are stated to possess an outer nitrogenous
and an inner cellulose coat.

BiBL. Haeckel, Qu. Mic. Jn. 1869, 33 ;
SchuUzes Arch. 1876, xii. 24.

VARI0LA'RL4.,Pers. — A spurious genus
of Lichens, founded upon imperfect forms
of Pertusaria &c.

BiBL. Hook. Br. Fl. ii. pt. 1. 172 ; Scha3-
rer. En. Crit. 229.

VASCULAli BUNDLES.— This title is
applied to the fibrous cords which form the
ribs, veins, &c. of the leaves, petioles and
other appendicular organs of all plants rank-
ing above the Mosses, and which by their
confluence and more considerable develop-
ment constitute the wood of stems and

trunks. The vascidar bundles of petioles
(tig. 660, page 711), &c., rimninginto leaves
to form their ribs, and lying imbedded in
parenchyma, resemble the Tmndles which
form the rudiments of wood of the stem
itself. The bundlesremain isolated as fibrous
cords in the stemsof the herbaceous Monoco-
tyledons, or are only combined into a wood,
in the Palms &c., by the lignification of the
cells of the parenchyma in which they are
imbedded (fig. 461, p. 508).

In the Dicotyledons, the rudimentary
bimdles are developed in a circle surrounding
the pith (fig. 455, p. 495), and soon unite
to form a tube of wood, with an external
cambium layer and a true bark j and the

Fig. 791.

Monocotyledon.

Transverse section of a fibro-Tascular bundle of a
Palm : the upper end is directed towards tlie centre of
the stem. «•, woody fibres resembling liber iu struc-
ture; s. V, spii-al vessels; c, cambium (vnsii propria);
d, ducts ; p, parenchyma ; /, liber ; I. c, laticiferous
canals. Magnified 150 diameters.

cambium layer is the seat of renewed de-
velopment of the vascular bimdle in each
successive year. On such characters of
growth, Schleiden founded a division of the
vascular bundles into classes which are con-
venient in reference to microscopical inves-
tigations, and affixed tolerably perfect syste-
matic characters to them.

In the higher flowerless Plants, viz.
Ferns, Eqiusetacese, &c., the vascidar bun-
dles are composed chiefly of ducts, sui--

VASCULAR BUNDLES. [ 801 J VASCULAR BUNDLES.

rounded by elongated tubular cells, almost
devoid of secondary deposits, the whole
enclosed by a layer of tolerably firm prosen-
chymatous wood-cells, especially developed
in the Ferns. In the Ferns, the ducts are
mostly of the kind called scalariform (fig.
664, page 712 ; PL 48. lig. 10), in the Equi-
setacejTQ annular (fig. 061, page 711), in the
Lycopodiaceje spiral (fig. 651), p^ge 711 ;
PI. 48. figs. 11 & 12). They are variously
arranged in the diflferent orders, but agree in
the mode of development, namely in grow-
ing only at the end next the j^unctiun vege-
tutiouis, iu proportion to the elongation of
the stem and the evolution of leaves. Hence
Schleiden called them shmilkineotis bundles ;
their various elements — ducts, tubular and
proseuchymatous cells — being formed si-
multaneously.

In the ^louocotyledons, where the vas-
cidar bundles occur isolated, they originate
iu the jmnctum vegetationis, and are deve-
loped with the growth of the stem, outwards
and upwards into the leaves, and outwards
and downwards towards the permanent cir-
cumference of the stem, old and new bundles
crossing each other in a more or less com-
plicated manner (fig. 461, page 508). Here
(fig. 791) the first trace of the vascular bundle
consists of spiral vessels, followed on the
outer side by spu'al, anniJai', or reticulated
ducts ; next comes a collection of elongated
tubular cells of delicate structure (vasa
in-opria), and in the outer part, at first, a
cambium region, which is gradually con-
verted into proseuchymatous woody struc-
tui-e having the character of LiBEB-cells.
In this case, the development is not only
gradual from the imnctum vegetationis out-
ward, but the iimer side of each bundle is
perfected first, and the conversion of the
outer part into wood occupies a whole
season of growth. Hence these are entitled
progressive bundles ; but as no new develop-
ment occm-s in these in successive seasons,
they are further distinguisbed fi-om those of
the' Dicotyledons as definite bundles. The
sti-uctm-e of the vasculai' bundles of Monoco-
tyledons is very well seen, in difterent charac-
teristic conditions, iu vertical and hoiizontal
sections of the stems of the white lily, of the
large grasses,rhizomes of sedges and rushes —
affording well-developed examples iu herba-
ceous structures ; of the bamboo (an arbo-
rescent grass), of the conunou cane or the
partridge cane (both species of Palms),
where the bundles are connected by lignified
parenchyma. In leaves of bulbous Monoco-

tyledons, &c., the bmidles consist chiefly of
spiral vessels ; in tlie palms, bananas, &c.,
the woody fibre extends also into the ribs of
the foliaceous organs.

In the Dicotyledons, the bundles of the
stem appear first as a circle of cords com-
posed of spiral vessels, around the pith, out-
side which larger vessels and ducts, and
subsequently woody fibre or wood-cells are
developed, passing into the elongated pros-
euchymatous liber (fig. 792). The develop-

Fig. 792.

Dicotyledon.
Transverse section of a fibro-vascular bundle of a
Melon stem ; the upper end next the centre of the stem.
p, pith ; s. y, spiral vessels ; m. r, medullary rays ; w,
wood ; d, pitted ducts ; c, cambium ; /, liber ; I. c, lati-
ciferous canals ; c. e, cellular enTelope of the bark ; e,
epidermis. Magnified .50 diameters.

ment of the successive regions is irrogressive
dm-ing the fii-st season ; but here the cam-
bium layer remains capable of renewed
activity, and a new layer of wood (and of
liber) is added on the outside of the bundle
in each successive season ; hence these bun-
dles are distinguished as indefinite. These
may be observed iu sections and yoimg
shoots of any common tree (figs. 455 & 4o7,
pages 495 & 496).

Infinite variety of modification occm's in
the character and aiTangement of the vas-
cular bundles within the limits above laid
down, or very slightly overstepping them.
A few remarkable cases may be mentioned
here ; in the Orobanchaceas (parasites) no
spiral vessels occur in the vascular bundles
forming the wood; in Victoria reyia the
isolated bimdles are composed of spiral
vessels without any proseuchymatous wood-
cells ; other peculiarities, influencing moi'e

3f

VASICOLA.

[ 802 ]

VAUCHERIA.

especially the characters of Wood^ are given
uudev tiiat article. Vasculose, the sub-
stance of which vessels are formed, is in-
soluble in hydrochloric and sulphuric acid,
and in cojiper solution, but is soluble in
boiling caustic potash. (See also Cambium
and Medulla.)

BiBL. Henfrev-Masters, Bot.; Sachs,
£ot.

VASIC'OLA,Tatem.— AgenusofHetero-
trichous Infusoria. Ovate, pointed behind ;
mouth anterior, surrounded by long cilia;
contained in a transparent carapace.

V. ciliata ; pond- water. (Tatem, 3Li.
Mtc. Ju. i. 117 ; Kent, Inf. Gl-S.)

VAUCHE'RIA,D.C.— An important and
to the microscopist a most interesting genus
of SiphonacefB (Confervoid Algse), consistiufi-
of gieen filamentous plants growing in fresh
and salt water and on damp ground, charac-
terized by the continuity of the cavity
throughout the branched tubular filament
(sometimes several inches long) of which
each plant is composed, and by the modes of
reproduction, both by gonidia and by spores.
VaucJieri(einajhe gathered on damp borders
in every garden, or by the sides of ditches,
where they form fine silky green tufts ; the\'
are very variable in form and size, so that
the specific distinctions heretofore laid down
appear to be worth httle. The ordinarily
occurring species presents itself as a tubular
cell of comparatively gigantic dimensions,
containing more or less protoplasm, coloured
by chlorophyll in the form of minute gra-
nules applied upon the wall or occupying
more or less of the cavity. The green gra-
nules may be seen to lie imbedded in a
colourless protoplasm at the inner surface
of the cellidose wall ; and it is curious to
observe when the filament is accidentally
or intentionally ruptm-ed that the green
granules which may escape are contained in
a mucous investment, which soon rounds
itself into a globular body, of size propor-
tionate to the quantitv of green granules
extruded ; these globules sometimes e^en
exhibit a sUght rolling movement, but they
appear ultimately to decay. Such globules
sometimes occur inside tlie filaments, when
the growth is unhealthy; and Itzigsohn calls
them spennatospheres, stating tliat they pro-
duce spermatozoids. This, like all this au-
thor's observations, requii'es confirmation.

If the Frt)/67<e/v«-filaments are gathered at
a favourable epoch, or if they are cultivated
in a vessel of waler well exposed to light,
the blmd ends of the filaments (or rather of

the ramifications of the filament) are found
very densely filled with green contents, ap-
pearing almost black ; and if these ends are
watched early in the morning, a remarkable
series of phenomena is observed in them.
The ends of the filaments about to produce
gonidia are found swollen into a slightly
clavate form ; the green contents of the club
separate from the general contents of the
filament, leaving a transparent space (fig.
703) ; then, having as it were acquired
a definite independence, the isolated mass
retui'us so as to fill up the transverse light
space, but does not again coalesce with the
lower mass of contents. Next, a light space
is observed between the surface of the ter-
minal body of contents and the cellulose

Fig. 793.

li

Fig. 794.

A'aucheria Ungeri.

Fig. 793. End of a ■filament in which a gonidium is
being developed.
Fig. 791. Gonidium escaping from the illament:.

Magnified 50 diameters.

wall surrounding it ; and the latter soon
gives away at the apex, forming a passage
for the escape of the contents. This mass
of contents is now clearly recognizable as the
(jonidium or zoospore ; it graduallv extri-
cates itself from the tube, with a rotatt^rv
motion around its own axis ; and it exhibits
a remarkable elasticity of structure, giving-
way and altering its form (fig. 794) to
sfiueeze tlirough the narrow orifice of es-
cape. Sometimes it becomes " pinched " in
this process into two independent gonidia
of half the usual size. As soon as it has
perfectly emerged, it assumes an elliptical
form, increa.ses much in size, and is seen to
be covered with inmunerable vibratile cilia
(fig. 790); arising from its gelatinous (pro-
toplasmic) coat (these are rendered much
more distinct by applying tinctm'e of

VAUCHERIA.

[ 808 ]

VAUCHERIA.

iodine) : no cellulose membrane exists at
this time ; and the <i:oiiidiiuu swims .about
actively inth e water, rovolvinf^ on its long
axis. The large number of cilia existing on

Fig. 795.

Fig. 796.

Vauoheria Ungeri.

Pig. 795. End of the filament from wliich the gonidiimi
has escaped. Majjiiilied 50 diameters.

Pig. 79i5. Gonidiuin which has been treated with
iodine and dried between two slips of glass, showing
the cilia very clearly. Magniiied 110 diameters.

this gonidium . distinguish it remarkably
from all others ; but we are inclined to be-
lieve that there is a nearer relationship than
appears at first sight. The green substance
at the surface of the gonidium presents a
pecidiar granular or globidar appearance;
and it appears not far-fetched to regard this
body as composed of a densely combined
family of ordinary two- or four-ciliated
zoospores, such as would be formed by the
swarming-spores of Hydrodictyon if they
remained in theii' primitive crowded con-
dition. This, however, is a point requiring
further examination. The end of the tube
from which the gonidium has escaped ap-
pears as a hyaline sac (fig. 795 j, which soon
decays down to the point where the con-
tents parted, where a septum, now closing
the tube, is developed.

After swimming about for some time,
from one to several hours (usually about
two), the gonidium falls to the bottom of
the vessel, its cilia disappear, and it assumes
a spherical form, acquiring very soon a di-
stinct cellulose coat ; after this it soon ger-
minates by pushing out one or more tubular
processes (fig. 797), which grow up into
filaments like the parent. Sometimes the
gonidium cannot make its escape ; sometimes
half of it escapes and becomes pinched oft,
the other half being left behind : in these
cases, the arrested body, or the remaining
portion of the divided one, germinates in
situ (fig. 798).

It should be mentioned that the contents

of the vegetative filaments have a remark-
able tenacity of life ; for if the tube is slightly

Fig. 797.

Fig. 798.

Vaucheria Ungeri.

Fig. 797. G-onidia germinating,
diameters.

Fig. 79S. Filament with gonidia germinating in the
parent tube; the left-hand figure, hal'' '- ' '
diuia. Magniiied 25 diameters.

Magnified about 15

germinating in the
naif a divided goni-

injured at any point, the primordial utricle
commonly retracts from the wound, and
secretes a cellulose layer (Xi its surface,
shutting off" the injured part. Filaments
are sometimes met with having several
living regions of this kind, shooting out
into branches, separated from each other
by dead, empty lengths of the filament.

Besides the vegetative reproduction above
described, the Vaucherice are repz'oduced by
spores formed by the concurrence of two
distinct kinds of reproductive organs. Fila-
ments growing on damp ground ordinarily
exhibit lateral organs of two kinds, asso-
ciated together, but variously gi-ouped and
collected in varying numbers at particular
points, apparently according to external
conditions. The larger kind of organ, or
sporangium, appears first as a pouch-like
process, which expands into a short flask-
shaped body, stalked or sessile, the neck of
which is gradually turned over in the
development, until it projects at one side ;
the form then somewhat resembling that of
a bird's head (or a chemist's glass retort cut
off short at the neck, PL o. fig. 12 a, b, s).
Near this, on the main filament, or on a
common pedicel with one or more of the spo-
rangia, is developed another organ, the an-
theridiuni, at first straight and tubular, but
soon curving over into the form of a hook or
scroll, without however expanding (PI. 5.
fig. 12 A, B, a). The sporangium becomes
filled with dense green granular matter, and
cut off" by a septum from the main filament,

3f2

VEGETABLE IVORY. [ 804 ] VEGETABLE KINGDOM.

The upper part of tlie antheridium is like-
wise cut oft' by a septimi ; and when matiu'e
it bursts at the apex and discharges biciliated
spermatozoids resembling those of Fucus,
which enter the simultaneously opened neck
of the sporange and fertilize its granular
contents. The contents become isolated
from the wall, secrete a proper coat, and
form a free cell (spore) lying in the sporange,
its green granular matter gradually becoming-
brown (PI. 5. fig. 12 c). Two coats, at least,
are developed ; and the spore idtimately
escapes by the decay of the parent filament
and sporange. According to Pringsheim,
about thi'ee months elapse before germina-
tion, in which process the outer spore-coat
splits, and the inner grows out into a
tube, forming the basis of a new ramifica-
tion of the Vaucheria-Hlaiiient.

In the systematic works on Algology,
nimierous species of aquatic and land T^au-
cherics are described ; but we agree with
Thiu'et in believing that the characters by
which most of the forms are distinguished
are imessential, therefore we omit any syn-
opsis of them. E^sen V. racemosa, Ue-
caisne, appears merely an extreme of the
kind of development producing V. yeminata.
Thuret proposes the name V. Ungeri, to in-
clude allbut V. racemosa; Hassall suppresses
the name V. clavata, as indicating a form
common to all the species, of which he de-
scribes a large number. We do not find
any thing sufficiently distinctive in the cha-
racters of the marine species cited by
Harvey.

BiBL. Vaucher, Conferves d'eau douce
(Ectosperma) ; HassaU,^/^. ; Harvey, Mar.
Alf/. 195; Unger, Nova Acta, xiii. 11, I}ie
Pflanze im Mom. cler Thicrwcrdiuuj , 1843 ;
Decaisne, Ann. Sc. Nat. 2. xvii. 430 ; Thuret,
ilnd. xix. 2G6 ; Ivarsten, Bot. Zeit. x. 85, xv.
1 ; Pringsh. Ber. Berl. Ak. 1855 ; Ann. N.
H. 2. XV. 346 ; Braun, Verjilng. (Ray Soc),
Aly. imicelL, 8, 105 ; NiigeH, Neues Alyen-
syst, 175, pi. 4 ; Itzigsohn, Bot. Zeit. xi.
225 ; Dippel, Flora, 1856, 481 : Rabenht.
Aly. iii. 267 ; Sachs, Bot. 275.

VEGETABLE IVORY.— This substance
consists of the seeds of the Palm called
Phytelephas macrocarpa, and is composed of
a large round mass of bimy Albi^mex, in
which a small embryo is imbedded. Slices
of this ivory-hke albumen, placed under the
microscope, afford very beautiful examples
of vegetable cells with the cavities almost
obliterated by Secondary deposits (PI.
47. fig-. 23).

VEGETABLE IvINGDOM.— The large
number of Natural Orders of Angiospermous
Flowering Plants, and the subordinate
characters of their diversities in microscopic
structui-e, lead us to depart from the plan
on which the Synopsis of the Animal
Kingdom is given and carry it into effect
hei'e only in reference to the Cryptogamic
plants. For the microscopic phenomena in
the Phanerogamia described in this work,
reference shoidd be made to the articles
Embryo, Ovule, Tissues, Wood, &e.

Ivingdom VEGETABILIA.

Subk. 1. Phanerogamia. Flowering plants.

Division I. Anyiospermia.
Class I. Dicotyledons.

Most common ti'ees and herbs.
Class II. Monocotyledons.

Grasses, rushes, most bulbous plants,
palms, kc.
Division 2. Gymnospermia.
Class III. C0NIFEB.aE.
Firs, pines, yew.

Class IV. CYCADACEiE.

Cycas, Zamia.

Subk. 2. Cryptogamia. Flowerless plants.

Division 1. Contiophytes or Acroyens.
Class I. Lycopodiales.
Order 1. Mabstleaceje.

Pilularia, Pill-wort.
Order 2. Lyx-opodiace^.
Club-mosses.
Class II. Filicales.
Order 1. Filicace^.

Ferns.
Order 2. Equisetace^e.
Horse-tails.
Class III. Muscales.
Order 1. MusCACEiE.

Mosses.
Order 2. Hepatic^.

Liverworts and Scale-Mosses.
(Order of uncertain place, Cha-

RACEiE.)

Division 2. JliaUophytes.
Class I. Alg.*;.

Order 1. Florid EiE.

lied sea-weeds.
Order 2. Fucoide^.
Olive sea-weeds.
(Pha20sporea3.)
Order 3. Confertoideje.

Green silk-weeds, slime-weeds,
and brittle-\veeds(Diatomaceai).

?5
GC

o

o
58

VEINS.

[ 806 ]

VERRUCARIA.

Class II. Lichens,
Class III. Fungi.

Order 1. Sciiizomycetes.

Bacterixm, Vibrio.
Order -2. Phycomycetes.

-Moulds aud mildews.
Order 3. IIvpODERMiiE.

Uredineaj, Ustilagineae, smuts, &c.
Order 4. Basidiomycetes.

Mushrooms, toad-stools, puff-balls.
Order 5. Ascomycetes.

Truffles, morells, &c.
Ordin- G. Myxomycetes.

Trichia, JEthalium, Lycogala,

BiBli. Lindley, Veg. Kingdom; End-
liclier, Gen. Plant. ; Fries, Summa Veget.
Scan.; Heufrey-Masters, Elem. Cowse ;
Sachs, Lehrb. Bot.

VEINS OF A^^iJiALS. — The walls of the
veius are thinner than those of the arteries,
which arises principally from the less de-
velopment of the contractile and elastic
elements. The inner coat is less developed,
but otherwise ao-rees with that of the arteries
in structure. The middle coat is not yellow,

Fio-. 799,

Longitndiuiil ecouon of the vena cava inferior, near
the liver, a, inner coat ; b, middle coat without mus-
cular fibres ; c, inner layer of the outer coat — a, its
longitudinal muscles; fi, its transverse areolar ele-
ments; d, outer portion of the outer coat, without
muscles. Magnified 30 diameters.

but greyish red, containing more connective
tissue aud fewer elastic fibres aud muscles ;
in addition to the transverse, it has longitu-
dinal layers. The outer coat is usually the
thickest, agreeing with that of tlie arteries,
except that in many veius, especially those
of the abdominal cavity, it contains well-
developed longitudinal muscular fibres.

The veins of the brain, the bones, retina,
^-^'c, contain no muscular fibres.

The large veins, near the heart, contain
transverse striated musciUar fibres.

BiBL. Kolliker, Hist. ii. ; ^hexi\x,Stricker''s
Hist. ; Frey, Hist.

VEINS OF Plants. — The name com-
monly applied to the ramifications of the
Vascular bundles, forming the ribs of
leaves and similar organs,

VENILI'NA, Giimbel. SeeTEXxuLARiA.
(Giimbel, Tr. Munich Acad. cl. 2, x. Q^^).

VERMES.— A subkingdom of the Ani-
mal Kingdom,

VERMICULA'RIA, Fr.— a genus of
Sphserouemei (Coniomycetous Fungi), but
seemingly stylosporous states of Spheeriacei,
most of the species being included under
Sphceria ia. the British Flora. They grow-
on decaying stalks, leaves, or wood. " S. re-
licina, Dematium, cuhnifraga, trichella, and
others of the Br. Fl. belong here. Another
species, V. atramentaria, is common on de-
caying potato-stems, forming black velvety
patches. This is distinguished from V.
Dematium by its straight spores. The erect
black hairs of the perithecia are character-
istic.

BiBL. Berk. Br. Flor. ii. pt. 2. 274, &:c.,
Ann. N. H. 2 v. 378; Fries, Smn. Veg.
419.

VERMILION, or bisulphuret of mercury,
is used as a pigment for injecting. It should
be in a finely divided state, in which it is
best obtained by levigation, and should not
exhibit any white crystalline particles when
examined as an opaque objeft.

VERNEUILI'NA, D'Orb, See Textu-
lama.

VERRUCA'RIA, Pers.— A genus of Py-
renodei (Lichenaceous Lichens), containing
numerous species having a cioistaceous or
cartilagineo-membranous thallus growing
upon and adherent to the bark of trees or
stones ; named from the wart-like ])rocesses
corresponding to the perithecia, which open
by a pore at the surface. The perithecia
have a black rind, enclosing either the
whole or the upper half of the nucleus.
The spermogonia much resemble the peri-

VERTEBRALINA.

[ 806 ]

VESSELS.

thecia, only they are mucli smaller ; they
occur either scattered among the perithecia,
or collected towards the margins of the
thallus. Species very mmierous.

BiBL. Hook. Br. Ft. ii. pt. 1. 152 ; Leigh-
iow,Lich. Fl. 444 ; Schferer, Emtm. crit. 213 ;
Tiilasne, Aim. Sc. Nat. 3. xvii. 215, pi. 3,

VERTEBEALI'NA, D'Orh.— A genus
of Porcellaneous Foraminifera, near Milioia.

Char. Shell free, regular, greatly com-
pressed, mostly inequilateral, more convex
on one side than on the other, suborbicular
or elongate ; spire embracing in the young
state only, afterwards straight; chambersin
the spire, two or three; orifice a large
patulous apertm-e along the septal plane.
See Articulina and Renulites.

One recent British species :

V. striata (PI. 23. fig. 10).

BiBL. Williamson, Bvc. For. 89 ; Car-
penter, Intrvcl. For. 72.

VERTICIL'LIUM, Nees.— A genus of
Mucedines (Hyphomycetous Fungi), distin-
guished from Botrrjtis (under

which it is included, with

Fig. 800.

Acrostalagmns, by Fries)
chiefly by the verticillate
arrangement of the spoiifer-
ous branches. A number of
species are described ; but,
from the observations of Iloft-
mann and Bail on the germi-
nation of Tricothecinm, this
genus represents only one
form of the plants belonging
to other genera, — V. niherri-
vtmn, Bonorden {Botrijtis rer-
ficilloidcs, Oorda, which Hulf-
maun regards as identical with v.itic-iiiium
Acrostalaf/mus 2)arasifaiis and cylimU-osporum.
cimmharimis), having been Magnified 200

, p ., c T, • dinmetcrs.

raised from the spores ot i ri-

clwthecium rustnim, and its " spores " being

barren (see Trichotiiecium). Berkeley

and Broome describe and figure several new

species.

BiBL. Ann. N. II. 2. vii. 101, pi. 7.
figs. 15-18; Fries, Smn. Vvij, (Ilofri/tis),
491.

See also Triciiotuecium.

VESICULA'RIA, Thomps.— A genns of
Infundibulato Ctenostomatous Polyzoa, of
the family Vesiculariidic.

V. spinosa, the only species, general on
marine shells, kc.

BiBL. Thompson, Zool. Illustr. 98 ; John-
ston, Br. Zooph. 370; Hincks, Pobjz. 512.

VESICULARITDJE.— A family of In-

fundibulate Ctenostomatous Polyzoa.

Char. Polypidom plant-like, horny, tubu-
lar ; cells free, deciduous, the ends flexible
and invertile. Genera :

Serialaria (Amafhia). Shoots slender,
filiform, erect, branched ; cells tubular, ad-
herent, uniserial and unilateral, rows inter-
rupted by blank intervals ; tentacles eight.

Vesicularia. Shoots branched, jointed ;
cells oval, distinct, uniserial and unilateral ;
eight tentacles, and a gizzard.

J'alkeria. Variously branched ; cells oval,
irregularly clustered ; eight tentacles, no
gizzard.

Miviosella. Variously branched ; cells
ovate, in two rows, opposite, jointed at the
base ; eight tentacles and a gizzard.

Avcnclla. Filifonn, creeping, nearly
simple ; cells large, solitary, scattered, in one
row, slightly contracted at tlie top, curved ;
twenty to twenty-four tentacles, and a small
gizzard.

Kolella. Cells erect, subcjdindrieal,
crowded on tubes which form an undefined
iucrusting mat ; tentacles eighteen.

Bou-erbankia (PI. 18. fig. 19). Matted
and creeping, or erect and irregularly
branched; cells tubular, densely clustered';
tentacles eight to ten, and a sti'ong gizzard.

Farrella. As Bou-erbankia^ but tentacles
twelve to thirty, and no gizzard.

Anguinella. Branched palmately, one
tube springing from another, largely com-
posed of mud ; animals with twelve tenta-
cles and no gizzard.

BiBL. Johnston, Br. Zooph. 307 ; Gosse,
3Iar. Zool. ii. 19 ; Hincks, Pohjz. 512.

VES'PA,Linn.- — Vcsjm vuhinris, thewasp,
and V. crahro, the hornet, are readily acces-
sible insects for the examination of the sting
(Sting).

VESSELS OF Animals. See Arteries,
Lymphatic system, and Veins.

VESSFJjS of Plants. — This name was
applied by the enrlier observers to various
elongaled (ubidar siriiclures of vegetable
tissues, I'rom an id(\a tliat t]u>y corresponded
with the vessels uf animals; and the name
is still retaini'd. The spiral, aiunilar, &c.
vessels are described under Si'Irai, Struc-
tures. The term vessel is now gent-rally
contrasted with duct, to indicate a single
long tubular cell, or row of conlliu'nt elon-
gated cells, with spiral (-econdary deposits
upon their walls, in contr-adistiucliun to a
canal formed of a row of cells, with pitted

VIBRIO.

[ 807 ]

VILLI.

secondary deposits, applied end to end and
conHuent. The Latioiferous tubes are
sometimes called laticiforous or milk vessels.

VIB'RIO, Miill.— A genus of Sckizoray-
cetes.

Char. Filiform, more or less distinctly
jointed from imperfect division ; flexible,
movement undulatory, like that of a ser-
pent.

Theso filamentous bodies are extremely
minute ; their simple structure is best seen
when thev are dried.

V. rvgula (PI. 7. fig. 19). Filaments
hyaline, distinctly jointed, very tortuoiis
when in motion. Warming describes a
cilium. In decomposing infusions ; breadth
1-1 2000' •.

V. haciUus (PI. 7. fig. 21). Filaments
elongate, hyaline, joints sometimes distinct
onlv after drying, flexuous in their slow
motiou; length 1-288" ; breadth 1-1700".

Fig. 801.

V. se7'pen8. Smaller than the last, with
tlu'ee or four undulations. In infusions &c.

BiBL. Ehr. /??/. 77 ; Duj. Lif. 216; Ra-
bonlit. iii. 71.

Vibrio /;7V/ri=ANOUiiiLULA tritici.

VICTOREL'LA, Kent,— A genus of
Ctenostomatous Polyzoa. ('ells formed in
open enlargements of the creeping stem;
tentacles few ; no gizzard.

V. pamla, YGvy minntQ; on Cordylophora
hicustris, in brackish water.

BiBL. Kent, Qu. Mic. Jn. 1870, 31;
Hincks, Polijz. .559.

VILLI. — These are minute folds or pro-
longations of the mucous membrane of the
small intestines. They are most numerous
in the jejunum and ileum — in the former,
conical and flattened, sometimes plate-like,
cylindi'ical, club-shaped or filiform, while
in the latter they are broader and flat-
tened.

Fig. 802.

Fig. 801. Intestinal villus of a kitten free from epitlieliimi, and after treatment with acetic acid: a, boundary of

^a ,'o?A^;.- J*''!"*''""'^''' '"' nuclei ofthe muscular fibres; c/, roundish nuclei in the middle of the villus. Mae-
nifled 3o0 diameters. ^>

Fig. 802. >1, magniflcd 75 diameters Two villi with their epithelium, from a rabbit: a, epithelium; 6, paren-
chyma. B ma^mUed .300 djameters. A row of detached epithelial cells: ff, membrane separated bv water. C.
magmflcd 3oO diameters. Detached epithelial cells : a with, h without the separated membrane ; e, surface view of
some epithelial cells.

The villi form solid processes of the mu-
cous membrane, consisting of connective
tissue without elastic elements, but abound-

ing in roundish nuclei; containing also
blood-vessels, lymphatics, and uustriated
muscular fibres.'

VINCA.

[ 808 ]

^INE-FUNGUS.

The villi are exceedingly vascular, and
form beautiful microscopic objects when
injected, exhibiting a network of capillaries

with rounded or elongate meshes
Fio-. 803.

x'uri^r II,

Fig. 803. Two villi from a calf, without epitheliiun,
and containing each a lacteal vessel ; after treatment
with dilute solution of soda. Magnified 3.50 diameters.

Each villus contains a lacteal, the origin
of which commences either in a single ccecal
dilatation, or in a network of branches.

Tlie muscular fibres form a thin layer,
not very distiuct in man, suvrouuding the
lacteals, and capable of greatl>- contracting
or sliorteuing the villi.

The epithelial cells are intimatelv con-
nected with each other, but easily detached
from the villi, often in groups or rows ;
the free surface is longitudinally striated.
When acted upon by water, the cell-mem-
brano at the surface is separated, leaving a
clear space between the granular cell-con-
tents and tlii^ former.

BiBL. Kiilliker, Mikrosk. Anat. ii.

VINCA, L. — The generic name of the
garden plants called Periwinkles ; interest-
ing to microscopists on account of their

striated liber-fibres (PI. 48. fig. 30).
Spikal Stkucturks.

Fig. 804.

See

Fig. 804. Two contracted villi, from a eat. Magnified
60 diameters.

VINE-FUNGUS. — The vine-mildew,
Oidium Tuckeri, Berk., which has in recent
years caused such extensive destruction, has
formed a subject of investigation for most
of the principal mycologists ; and notwith-
standing that its natm'al history is not yet
wholly cleared up, many interesting points
have been discovered. As it ordinarily
appears, it forms a white and very delicate
cottony layer upon the leaves, young shoots,
and fruit of the vine, soon causing a pro-
duction of brown spots upon the green
structures, and subsequently a hardening
and a destruction of the vitality of the sur-
face. Under the microscope, the white
substance is seen to be composed of delicate
ramified filaments, creeping horizontally
over the surface, and, when the phuit is
much developed, forming a dense interlace-
ment. The hoiizontal filaments exhibit
few septa, these occurring at the points of
branching, and they do not penetrate into
(he inferior of the epidermal layer ; here
and tlicre, however, they are found fixed to
the epidermis by a more or less develojied
organ of attachment, consisting of a disk or
lobed expansion, comparable roughly to tlie
so-called root of some of the Fucoid Algaj,
which adheres firmly to the cuticle, and
when removed, lea\es a brownif^h scar be-
hind. The destructive eft'ect of the Fungus
seems to arise from its arresting the de-
velopment of th(^ epidermis, by binding its
structiu'es together, and excluding the sur-

VINE-FTTNGUS.

[ 800 ]

VINE-FUNGUS.

faoe from the iiifluonco of tlie air, since
when young biu'ries are invaded, the inter-
nal development proceeds, and the sphace-
lated epidermis preventing the natural ex-
pansion, the grapes burst and rot. In this
case, species of Botrytis, &c. appear upon
the decomposing pulp, as on all siniilai" sub-
stances ; and these must be distinguished
fi'om the proper mildew. When full-grown
leaves are allected lo a moderate extent,
the vitality is often only partially affected,
causing a laxity of the tissue, and more or
less fading of the green colour, without
inevitable decay.

When the mildew is observed with a low
magnifier, its surface exhibits a mealy ap-
pearance, arising from minute bead-like or
pearly shining bodies of oval form ; and the
application of sufficient power shows that
the horizontal filaments bear numerous
erect branches or pedicels, consisting of
short-jointed filaments (PI. 26. fig. 8), the
terminal cells of which (oi* the last two) are
elliptical and expanded. These terminal cells
are soon matured, and then fall off"; vast
numbers of them are produced, and are
found lying upon the surface among the
creeping filaments, where they quickly ger-
minate (PI. 2(3. fig. 9) and produce new
ramifications of mycelium. The fungus, as
thus desciibed, constitutes the Otdiiim pro-
per ; and the deciduous terminal cells form
the so-called spores. But the history of
the development of the mildew does not
cease here.

In the first place, the detached ' spores '
do not always produce a filament as repre-
sented in fig. 9; some of them present,
while slill attached, a kind of segmentation
of the protoplasmic contents (fig. 10) ; and
detached examples are found filled with
minute ' sporides ' of elongated-elliptical
form. These minute ' spoiniles ' are either
discharged by a dehiscence of the ' spore '
(fig. 11), and then germinate, or sometimes
they germinate in situ and send out slender
filaments through the walls of the spore.
We have found also that the large filaments
produced by the simple large ' spore ' (fig. 9)
do not always at once form a regular myce-
lium, but sometimes give rise to slender
pedicels, terminating in a point bearing-
minute solitary corpuscles of about the size
and form of the 'sporules' above described,
and resembling the spermatid of many of
the higher Fungi.

In addition to this, we have sometimes
observed those ' spores ' which produce the

' spornles' in tlieir interior, with their outer
membrane finely })unetate ; and in very rare
cases this form of fruit was not composed
of a single terminal cell, but presented indi-
cations of cross septa, as it two or more
cells of the smnmit of the pedicel were con-
fluent into one sac ; here the pmictuation
of the surface was veiy strongly marked.

Thus far we depend upon our own obser-
vations ; but Mohl, Tulasne, and others de-
scribe a still more highly developed fi'uit
than that last noticed : they have foinid the
terminal body, producing * sporules,' with a
distinct celliilar coat (Pi. 20. fig. 12), from
which the sporules are discharged by a ter-
minal dehiscence. Mohl found this body,
very rarely, of spherical form. We have
never seen this cellular coat ; in the cases
we have met with, the coat was certainly
only punctate or tubercular ; probably the
structure was not mature, nevertheless the
^ sporules ' were distinctly evident.

These phenomena, exhibited by the Vine-
fungus, clearly agree with those exhibited
by the Oidia always accompanying certain
Erysiph^e, as described under that article ;
and therefore most of the authors who have
written on this subject conclude that the
Vine-fungus is really an Erysiplie, of which
the perfect, ascophorous fi-uit has not j^et
been discovered. A comparison of figure
12, PI, 26, from the Vine-, copied from
Mohl, with those of the Wa^-Erysiphe, fig.
14, will show the agreement of structure
between the two plants.

It remains only to add a few remarks as
to the interpretation or nomenclature of the
different organs. Mohl, Tulasne, &:c. have
denominated the simple ' spores ' above de-
scribed (figs. 8, 9) coiiidia ; but as we have
stated, the cells are convertible into what
may be called sporanyes, producing 'spo-
rules' (or true spores) without alteration of
structure. When their walls become cel-
lular (fig. 12), the sporangial character is
more decided ; but as the Erysiphce produce
a more perfect sporanye, in which asci are
developed, the name of pycnidia is applied
to them. This fruit it was which gave rise
to the establishment of a supposed distinct
genus, by Cesati, under the name of Ampe-
lomyces ; while Ehreuberg, also regarding
it as a distinct plan.t, made it the type of a
genus called Cicinobohis, on account of the
pecidiar tendril-like extrusion of the 'spo-
rules ' (fig. 12s). Mohl distinguishes it as
the Cici7iobolus-h'mt, which he, like Tidasne,
finds constantly associated with other (un-

VINEGAR.

810

VINEGAE-PLANT.

doubted) Erysiphce (fig. 14), in very slightly
different and equally irregidar forms.

There can be no doubt Avhatever, that it
is the cause and not a consequence of the
'murrain;' still there are various curious
circumstances connected ■with it not at all
understood. It is probable that peculiar
atmospheric conditions induce predisposing
states of the plants : but the phenomena
are enigmatical : we have had it completely
covering a vine in a small greenhouse, de-
stroying all the fruit one year; and although
no precautions were taken (as it was desired
to study the disease), no sign of mildew
appeared there the next year ; wliUe on an
out-door trellis, a few yards oif, the disease
reappeared in a slight form in the second
season. The application of sulphur appears
to arrest the growth.

BiBL. Berkelev, Qardener''s Chron. 1847,
no. 48 ; Jn. BoH. Soc. vi. 284, ix. 01 ; Mon-
tague, Bull. Soc. Centr. Agric, 2. v. ; Jn.
Iloi't. Soc, ix. 112; Amici, Atti cMF Accad.
de' GeorffofiU, xxx., Jn. Hort. Soc. viii. 231 :
Savi, ibid. 241 ; Tulasne, Bot. Zeit. xi. 2o7 ;
Compt. Bendus, xxx'^ii. ; Thuemeu, Pihe d.
Weinstocke, 1878.

VINEGAR, Eels in. See Anguillttla.

VINEGAR-PLANT.— Under this name
is known a remarkable vegetable production
formed in fluids rich in sugar, when under-
going fermentation at ordinaiy temperatures
and conversion into vinegar. As ordinarily
met with, it forms a tough gelatinous mass
floating on the surface of the liquid, its
shape (superficially) defined by that of the
vessel in which it is contained, extending
itself so as to occupy the whole surface even
in very large pans, — its depth or thickness
depending on its age and the amount of uli-
triment contained in the liquid. The gela-
tinous substance decreases in density from
above downwards, the lower part being very
lax and flocculent, the inferior surface being
in a state of continuous development. The
general mass, however, displays remarkable
tenacity, which, together with its lubricity,
renders it difiicult to tear ; but if the lower
surfiice is examined, it is found possible to
strip ofl" layer aftei* layer, each a few lines
thick, to an extent depending on conditions
of growth, the lower, less dense portion
being thus distinctly stratified.

When portions are placed beneath the
microscope, very varied forms of structure
are discovered in the interior. The general
mass of jelly appears structureless, as if
formed by some exudation, or solution of

the organized portion ; but the mode of ori-
gin of this jelly is not yet ascertained.
Imbedded in the jelly are cellular structures,
polymorphous indeed, but exhibiting trans-
itions which render it impossible to regard
them as of distinct origin. In the middle
portion often occiu' innumerable isolated
masses of short rows of cells, resembling
the cells of Yeast when coherent, except
that they are generally elliptical ; some of
them have short cylindrical joints : others
short cylindrical portions arising from long
tubular filaments, and terminating in ellip-
tical cells, so as to resemble exactly Oidium.
The diameter of all these structures is most
variable, from 1-4000 to 1-8000". In the
upper part, the elongated branched filaments
more aboimd, the length of the intemodes
and the diameter of the tubes still varying
extremely. At the lower, laxer surface^ the
ceUiilar structures are accompanied by less
of the tough gelatinous matrix. The lami-
nation of the lower growing surface is very
curious, but may perhaps be accounted for
by supposing that the inferior growing sur-
face of the mass, which is certainly the
mycelium of a fimgus, periodically produces
a crop of conidia, which become detached
and fall into the body of the liquid on which
the mass floats ; there quickly germinating,
they form a new entangled mass of filaments
and chaplets of cells, which then acquires
its gelatinous consistence, and, buoyed up
by the liquid, applies itself against the lower
surface of the parent mass, with which it
adhei-es, more or less, on account of the gela-
tinous condition. In the upper part of old
and thick masses, the layers become insepa-
rable— probably in some measure from the
pressure of the floating force from below,
together witli the condensation arising fi'om
the evaporation of the liquid of the jelly at
the upper surfiice.

When a vinegar-plant is left upon the
solution after the saccharine matter is ex-
hausted, we find it always display, after a
certain time, patches of the ordinary fructi-
fication of PENICILL,IUM///«?<eH?H (fig. 805),
as stated by Turpin and others, forming
green, blue, and yellow "mould'' upon the
surface, and imbedded in the upper strata,
in which also heaps of the spores occur;
the vinegar sometimes ultimately suffers
more or less decomposition, so that the
common " mother " of vineo'ar, which by
its gT0^vth destroys the acidity, appears to
be another condition of this same organ-
ism. In some cases where we kept an

^'INEGAR-PLA.NT.

C BU ]

VITTiE.

Penicillium.

bearing strings of spores.
Magnified 250 diametera-

exhausted liquid in
the dark for some
mouths, the acidity
of the vinegar dis-
appeared, the gela-
tinous layer becauio
greatly condensed,
and assumed a briglit
crimson tint, and re-
mained as a dull-red
membranous film,
somewhat like a
smear of blood when
di'ied upon paper.

From tlie above
observations it woidd
appear that the vine-
gar-plant consists ofH'^f'cl.of a (■"•'""„ ^1^™«"*
the mycelium of Peni-
ciUinm glamum^ vege-
tating actively and increasing also by crops
of conklia or gemmre. This opinion is en-
tertained by Turpin, Berkeley, and other
observers; and the various genera and species
founded on the different forms of structm'e
occurring in it cannot be entertained :
among these are Ulcma, Kiitz., and species
of Hygrocrocis, Leptomitns, ike. But the
moniliform growth is at the same time
scarceK distinguishable from the Yeast-
plant by any satisfactory characters ; and
repeated observations strongly impress us
with the idea, that these objects are all
referable to one species, — the viuegar-plant
being the form of vegetative growth taking
place at low or ordinary temperatures in
highly saccharine liquids, while the true
yeast-plant'or Torida is formed in the more
rapid fermentation taking place at more
elevated temperatures. Another circum-
stance, mentioned under Penicillium, is
that we have foimd stale beer-gi'ounds, kept
at a rather low temperature, always ulti-
mately acquire a gelatinous crust, on which
PeniciUutm-hmt becomes developed.

In Connexion with this subject may be
mentioned the objects called C'rijptoccoccus
<jh(tinif>, Fres., and the '^ blood on bread,*'
which appear nearly related to the red-co-
loured condition of the vinegar-plant abo^•e
mentioned. These are possibly merely forms
of the same plant; indeed we have observed,
on some fiom'-paste partially covered with
PeniciUium (jlaKciim, small circular patches
of a crimson tint, which under the micro-
scope were found to consist wholly of mi-
nute elliptical bodies, generally exhibiting
two internal gi-anules or "nuclei," and

exactly resembling the articulations of some
of the moniliform structures of the vinegar-
plant, which readily separate into their
component cells. All these phenomena
require further investigation, to which long-
contiuued and constant observation must be
applied in order to ascertain with certainty
the relation the different objects bear to
each other. It is a kind of research occu-
pying much time, and demanding great
care and patience, but calculated to repay
the trouble far better than the amassing of
isolated characters of forms seen at different
periods and under special conditions. Fur-
ther particulars concerning various points
treated in this article will be found mider
the heads Fermentation, Oidium, Peni-
cillium, ToRULA, and Yeast.

BiBL. Turpin, Mem. cle VInstifnf, xvii.
135 ; Berkeley, Jn. Hort. Soc. iii.91 ; Lindley'a
Med. Bot. 17; Fresenius, Beitr. z. Mycol.
Heft ii. 77 ; Slack, Tr. Mic. Soc. I860, 10.

VIRGULA'RIA.— A genus of Pemiatu-
lidae (Alcyonaria). V. mirabilis is found in
British seas, and has a long rod-like support
to the short polype-bearing fringes.

VIRGULI'NA, D'Orb.— A subgenus of
Bulimina, having outdrawn, very delicate,
and smooth biserial shells, with extremely
fine pores. The regular VirgnUnce are ty-
pified b}^ V, squamosa, those of less regular
growth by 7^'. Schreihersii. The only variety
taking on a sandy condition, becoming de-
licately rugose or subarenaceous, is V.Hemp-
richii, common in the Indian seas and in
some Tertiary and Cretaceous strata, having
muddy dull shells of very variable growth,
and presenting passages of form between V.
Schreihersii and Bulimina proper. See Bo-
LiviNA and Bulimina. Common, recent
and fossil.

The extreme subcylindrical modification
of Virgtdina is PleurostomeUa, Reuss ; the
bi-uui-serial modification is Bifarina, P.«&J.

BiBL. 'Ehrenher'2,Mikro(/.: Parker& Jones,
Phd. Tr. civ. 075; Aim.' N. II. 4. ix. 284,
299.

VIS'CUINr, Tjinn.— A genus of Lorantha-
ceje (Dicotyledons).

T^. album is the mistletoe, alluded to under
Embryo-sac, Liber, and Ovule.

\TTREOUS HUMOUR or bod v. See
Eye.

VITT^ of the valves of the Diatomacese.
— These are internal projections or inflections
of the valves, forming imperfect septa; they
appear as dark lines, visible mider ordinary
illumination.

vrTT^.

[ 812 ]

YOLVOCINE^.

VITT^ OF FRUITS, See Secbeting
Organs of Plants.

VITTA'RIA, Sm.— A genus of Grammi-
tideae (Polypodiaceous Ferns). Several
species ; tropical. (Hooker, Srjn. 895.)

VOLUTELLA, Fr.— A geuus of Stilbacei
(Hyphomycetous Fungi), compiising seve-
ral species of parasites which have been
variously distributed. The plants consist
of minute fleshy papillse (stromata) of cel-
lular structure, the surface of which is
clothed with elliptic, oblong, or fusiform
sty lospores, from between which project long-
jointed hairs (fig. 800) traversing the stroma.

Fig. 806.

Volutella buxi.
Maj^iififd 20 diametera.

It may be desirable to give the synonymy
of theseplants according to Berkeley and
Broome.

V. ciliata, Fr. (Psilonia rosea, Br. FL).
Whitish or rosy ; on potatoes.

V. buxi, Berk. & Br. (Fusisporium huxi,
Br. Fl.). White; on dry box-leaves (fig.
806).

V. setosa. Berk. & Br. {Psilonia setosa,
Br. Fl^JEffevitaset, Grev.). White, onwood
and herbaceous stems.

V. hijamithorum. Berk. ScBv.(Psil. h/ac,
Br. Fl.). White ; stipitate ; on hyacinths
grown in water.

V. mehtloma, B. & Br. Orange, with
black hairs ; on sedges.

BiBL. Berk. Br. Fl. ii. pt. 2. f.52-3 ; Ami.
N. H. 2. V. 460, pi. 11. fig. 3: Greville,
Cnjpt. Fl. pis. 102 & 208. fig. 2 ; Corda, Ic.
Fmuf. ii. pi. 13. fig. 107 ; Fries, Syst. Myc.
iii. 447.

VOTA'OOIN'E/E.— A family of_ Confer-
void Algte; they were formerly included
among the Infusorial animalcules, among
which they form one of Ehrenberg's families.
The most striking general character of these
objects is their composition of individual
elements, which exhibit in their mature and
most perfect stage of existence, the charac-
ters of the transitory zoospores of the other
Confervoids. The Volvocinete may be cha-

racterized as plants composed of a number of
permanently-active zoospore-like bodies
associated together into families of definite
form, in which the members, connected or
held together in various ways by cell-mem-
branes, retain their distinct individuality for
all physiological purposes of nutrition,
growth, reproduction, &c., but represent only
one being in relation to the surrounding
objects. Protococeiis, however, consists of
only a single cell. The best-known and
most beautiful example of this family is the
genus Volvo.v (PI. 7. fig. 24), consisting
when mature of a spherical membranous
sac, at the periphery of which, within the
membrane, are arranged a large number of
zoospore-like bodies (f/oniclt a), ea.ch provided
with a pan* of cilia, which pass out through
the enveloping membrane, collectively form-
ing a coating aU over the external siirface,
and by their vibration causing a rotary mo-
tion of the entire globe.

The modes of reproduction of the Volvo-
cinea3, both vegetative and by spores, are
described under Pandorina, Volvox, and
Gonitjm; hence it is unnecessary to dwell
on them here.

Char. Permanently active zoospore-like
bodies, ciliated (except Gyges), surroimded
by a gelatinous coat (like Coccochloris) ;
solitary or combined in definite groups, with
or without a common enveloping membrane.
Individuals pyriform, or with the body pro-
longed posteriorly.

Solitary.
Without cilia Gyges.

Withapairofoilm {(ChhimiJomoiias.)

Grouped.
Forming a square layer, goui- 1 g„„;,„„.
dia with two cilia J

Forming a spherical body.
Cilia solitary.

With a " tail " Urogfenn*.

Without a " tail."

Without an eye-8pot,i , ,„,_

with special coats ...J •' "^
With an eye-spot, go- i

nidia dividing into ^ SpkcEvosira*.

clusters )

Cilia two.

Without an eye-spot... Sgnvra*.
With an eye-spot.
Common envelope spherical.

Gonidia numerous, !iii\rolvox.

over the periphery... )
Gonidia eight, in a bir- j stephunosphar^ .

cle at the equator i ^ '^

Cominou envelope ellipsoidal, gonidia sixteen

or thirty-two Faiulorina.

* Probably stages of development of VOLVOX or Pan-

D OK IN A.

VOLVOX.

813 ]

VOLVOX.

See SpoNDYLOMonrM aud Sycamiua.
Bii?L. See tlie geuera.
VOLVOX, L. — A o-emis of ^'olvocine0e
(Confcrvoid Alg;v), of which ouly one spe-
cies, V. ylohator (PL 7. tig. :24), seems satis-
factorily established. This orgauism, occur-
ring not unconuuonly and often in great
abundance in clear pools on open conmions,
&c., appears to the naked eye as a minute
pale-green globule gently moving about in
the water ; its dimensions variable, but gene-
rally about 1-50" wheij. full-grown. When
placed under a low magnifying power, it is
found to be a spherical membranous sac or
coenobium, studded all over with green points,
the entire body rolling over in the water
with a motion which is readily discerned to
be caused by innumerable cilia arranged
upon the siu-face of the globe. In the inte-
rior of the sac are generally seen dense
globes, in summer mostly of a green colour
(PI. 7. fig. 24) : sometimes the cavity is
whoUy filled up by a number of membranous
sacs exactly resembling the parent but de-
fomied by mutual pressm-e (PI. 7. fig. 25) ;
and inside these are seen smaller green
bodies as in the former case. The cceno-
bium is also flexible, yielding to pressure
and recovering its form, and in fuU-growa
specimens is generally ruptm'ed at one point,
where the internal bodies escape, so that
the number varies; usually, however, the
original number is eight.

The application of higher powers is requi-
site to discover the intimate structure of
Volvo.v, which, by the researches of Wil-
liamson aud Busk, most of whose observa-
tions we have verified, has beeu pretty
clearly made out. The outer envelope con-
sists oi a layer of cell-membrane, in all
probability composed of a modification of
cellulose, although Ave have never succeeded
in producing more than a faint purple tinge
with sidphuric acid and iodine. By the
applicatiou of a suflicieut magnifying power,
the green corpuscles at the peripheiy are
found to consist of zoospore-like bodies (go-
nidia, PI. 7. fig. 28), which are seated inside
the membranous envelope, each sending out
its pair of vibratile cilia (figs. 24-30) through
separate orifices in the external coat. The
same investigation will reveal that the
green gonidia have radiating processes ex-
tending from their sides, and running from
the ditlerent centres to meet each other in
the light interspace, forming thus a kind of
delicate network beneath the membrane.
The gonidia are pyi-iform, have a transpa-

rent anterior end bearing a pair of cilia,
and contain a reddish-brown eye-spot and
a contractile vacuole, thus exactly resc^mbling
those of Gviiiuui, and indeed the zoospores
of Coufer\oids generally. The radiating
processes resemble those found in particular
stages of Pkotococcus pluvialis, running
through the gelatinous coat, and probably
may be compared to the radiating fila-
ments proceeding from the nucleus of Spi-
KOGYBA (PI. 9. fig. 26). There is somewhat
more difficulty in deternduiug the nature of
the structure in which the gonidia are en-
closed. There is a layer of soft consistence
of some thickness within the external mem-
brane ; the green gonidia are wholly im-
bedded in this ; and their radiating processes
and cilia traverse the substance of it. We
are inclined to believe that this presents a
firm membranous layer again at the internal
surface, looking toward the general cavity
of the sphere. The nature of the soft laj'er
has beeu the subject of discussion ; we be-
lieve Busk's view to be correct, that it is
not formed by the collocation of distinct
membranous cells, like those of ordinary
parenchv^niatous structures, but by the close
juxtaposition of gelatinous envelopes of the
individual green bodies, resembling- those
of Coccochloris, Gloeocapsa, &c. We could
never detect a true line of demarcation
halfway between neighbouring gonidia :
an appearance is indeed sometimes pre-
sented in preparations Ivept in chloride of
calcium, which nught lead to an error on
this point ; for the outer membrane is then
sometimes swollen into papillfe opposite
each corpuscle (PI. 7. fig. 30), the furrows
between which in certain foci give the ap-
pearance of a septum running round each
corpuscle (PI. 7. fig. 29). Similar prepara-
tions also often show the gonidium con-
tracted and leaving an empty ring round
it, separating it from the gelatinous coat,
which runs uudistinguishably into those of
the neighbouring gonidia. But the strongest
fact we have observed is that, by the appli-
cation of solution of potash, the substance
surrounding the gonidia is so entirely dis-
solved that the oily substance extracted
from the green bodies will run freely about
beneath the external membrane (apparently
confined internally by another film), in
sheets extending over considerable segments
of the sphere, yet leaving the gonidia and
their radiating processes intact, or at least
only shrunk and discoloured. If a true cell-
membrane existed around each gonidium,

VOLVOX.

[ 814 ]

VORTICELLA.

forming- septa dividing them, the above
phenomenon could not display itself, since the
potash would not so dissolve the structures.
The modes of reproduction of Volvox
have recently been entirely elucidated. In
certain conditions, some of the gonidia ap-
pear larger than the rest, and as if under-
going division (PL 7. fig. 27) ; it is possible
that some of the gonidia, or of such grouped
gonidia, escape into the cavity, and there
become developed into tlie large green bo-
dies (PI. 7. fig. 24), which are rudimentary
globes; but Williamson believes these are
detached in an earlier stage : perhaps both
modes of development take place. Forms
with the grouped gonidia (PL 7. fig. 29)
woidd appear to represent Ehrenberg's
Spharosira. Ehi'enberg's genus Uroglena,
again, would seem to be a Volvox either im-
perfectly developed or decaying.

The deep-green bodies (PL 7. fig. 24),
seen in the cavity of the spheres, are young
Vvlooces, and in an early stage the}' appear
as spherical cells filled with gi-anular green
substance ; the green substance divides by
segmentation (PL 7. figs. 31, 32) until it
forms a gi-oup of gonidia, on each of which
a pair of cilia appears , the enclosing mem-
brane expands, and they follow it and re-
move apart, until they form a perfect Vol-
w.r-sphere, studded with the gonidia. As
above mentioned, a second generation is
sometimes met with in the parent sphere
(PL 7. fig. 25) . We are uncertain whether
to regard the objects represented in PL 7.
fig. 14, as the young of Volvox ; they would
seemingly equally represent the genus Pan-
dorina, Syncrypta, or jEitdorina, Ehr.

Volvox, examined in autumn and early
winter, often exhibits either the green bodies
with a thick coat (PL 7. fig. 33), or the inner
globes are of an orange colour (PL 7. figs. 26
& 34), which appear to be successive stages
of de\-elopment of a restinci-spore. When
mature, this possesses at least two coats,
one immediately siu-roimding the granular
contents, another at some distance outside
the former, transparent, colourless, and as
it were glassy and brittle, breaking with
shai"p-angled cracks Avhcn pressed (PL 7.

figs. 34 &

A\'e cannot detect any in-

termediate substance or layer, which would
be required to complete the analogy with the
resting-spore of Spirogyra as described
by Pringsheim (PL 9. fig. 21) ; perhaps it
does not exist in either case. Sometimes
the outer coat of the enclosed yellow globes
is tuberculated or covered with conical ele-

vations (PL 7. fig. 30). The form with the
smooth yellow restiug-spores (PL 7. figs. 26
& 34) represents Ehrenberg's Volvox aureus,
and the form with the spines (PL 7. fig. 30)
his V. stellatus. The development of the
resting-spores of Volvox has been fully de-
scribed by Cohn, and presents an essential
resemblance to the process in Paxdouina
and Stephanospilzeea. Some of the
gonidia become enclosed in special cyst-like
coats'; and their contents are then converted
into spermatozoids, which break out and
move actively in the interior of the spherical
common envelope. These bodies fertilize
other gonidia, Avhich take on the function
of spore-ceUs ; and after their impregnation
the latter acquire the firm coats and yellow
contents characteristic of the resting-spores.
They are set free at first into the common
cavity of the spherical envelope.

A doubt remains as to the natm-e of the
object described as Synura uvella ; it may
belong here, or, not improbably, to the
genus Uvella (PL 32. fig. 18), which itself
may bo no more than a complex form of
Protococcus or Chlamidomonas (PL 7,
fig. 2 ; PL 23. fig. 30), which doubtless in-
cludes also Chlorogonium (PL 30. fig. 31),
Crypto(/lena (fig. 35), and Cryyes (PL 50.
fig. 14).

When a pool contains Volvox, the indi-
viduals are generally abundant, and may be
readily seen by the naked eye, as pale-gi'ecn
globules, in a phial of water held up to
the light ; but they are kept with difficulty,
being devoured by Rotatoria, &c. The
cilia are best seen by di-^ang and wetting
them again, or by applying iodine. Tlie
gonidia are a good deal altered by chloride
of calcium.

BiBL. Ehr, Inf. ; Pritchard, Inf. ;
Williamson, Tr. Phil. Soc. Manchester, vol.
ix. ; Tr. Mic. Soc. 2. i. 45 ; Busk, ibid. 31 ;
Cohn, Ann. Sc. Nat. 4. v. 323 ; Ann. N. II.
2. xix. 187 ; Rabenh. Aly. iii. 20 ; Cooke,
Alf/ce, 1882.

VORTICEL'LA, Linn.— A genus of
Peritrichous Infusoria, of the family Vor-
ticellina.

C/iar. Body campanulate, with an ante-
rior ring of cilia, stalked ; stalk simple, spi-
rally contractile.

These interesting Infusoria are very com-
monly met with in decomposing vegetable
infusions, as of hay, portions of dead
flowers, ifcc. Their curious metamorphoses
and modes of reproduction, are noticed under
Infusoria.

VORTICELLINA.

[ 815 ]

WATER

V. nchdifera (PI. 32. fig. 21). Body
conico-campauulate, colom-less ; anterior
margin dilated ; body witliout rings when
contracted. Length of bodv -nithout the
stalk 1-570 to 1-288".

V. microstoma (PI. 32. fig. 2G, body
with genimoe). Body ovate, narrowed at
the ends, greenish white ; anterior margin
not dilated, nor bodv ringed when con-
tracted. Length of body 1-2000 to 1-250".

V. convaUaria, Body ovato-couical,
whitish hyaline, annidate; expanded ante-

rior margin slightly prominent. Length of
body 1-4.30 to 1-240".

Many other species.

Dujardin unites the genera Carcliesmm
and Zootlunnnium to his genus Vurtkella.

BiBL. Ehr. Inf. 269; Duj. Inf. 546;
Lachmauu, Ann. N. II. 1857, xix. ; Clap,
ot Lach. Inf. ; Greef, Ann. N. H. 1872, 105,
106, 384, 462 ; AUman, Mn. Mic. Jn. xiv.
178 ; Kent, Inf. 667.

VOllTICELLI'NA.— A family of Infu-
soria.

Table of Genera.

I A. peduncle.

/ Peduncle
contrac-
tile.

branched

-«1

HH
Hi

W

o

I— I

o
>

'Without a pos-
terior crown
of cilia during"
the greater
part oilifc.

/ Naked. ■{

iTSot branched

^ /Each branch having

branched. ]^«P«3tg\--l°

( muscle .

Peduncle not contractile

Posterior part of]
body attached
by a disk. J

No disk

f No true sheath, the peduncle lost in a gelatinous mass

^ [ ^i'l'lc^^f fl!^ I Sheath fixed bv its base

I- A sheath. < gheath f Sheath fixed by its side. .

I Animal susi^ended freely in the sheath

With a i^osterior ciliary crown during the whole of life; body free

No pedun-l
cle. 1

I A helical funnel in front
I No funnel

Sheathed.

Q-ENUS.

VorliceUa.

Carchesium.

Zoothani Ilium.
Epislijlis.

Spirochona .
Scyphidia.

Gerda.
Ophri/diu»i.

Cothurnia.
Vaqinicola.

ZagenopJiri/s.
Trichodina.

BiBL. Clap. & Lach. Inf. 93; Allman,
Qu. Mic. Jn. 1872, 393.

YORTICLA'VA, Alder.— A genus of
Hydi'oid Zoophytes.

Char. Polypes on simple stems, developed
at interAals on a creeping filiform stolon ;
tentacles in two dissimilar whorls, the oral
short and capitate, the outer longer and
filiform ; reproduction imknown.

Two species, on stones and corallines.

BiBL. Hincks, Hych: Zoopli. 131; Wright,
Qu. Mic. Jn. iii. n. s. 50.
\TJLVULI'NA,D'Orb.— SeeTEXTULAEiA.

W.

WART. — The common hard wart con-
sists of a circular group of elongated papillie
with their free extremities slightly enlarged
and bulbous, their vessels dilated and ex-
tending close up to the epithelial covering.
This presents its normal threefold division,
inasmuch as a thick layer of transition-cells
fills up all the interstices between the en-
larged papillaj, while the horny lamina in-
vests the group of papilla3 with a common
covering. (Rindfleisch, Path. Hist.)

WASP. See Vespa.

WATER.— Under this head we might
form a kind of index referring to a large
proportion of the articles of which this

volume is composed, since water, existing
under different cu-cumstauces, forms one
of the most fertile sources of microscopic
objects ; but as om* space and plan do not
admit of such an enumeration, we must be
content to dwell shortly upon two of the
most important questions in which the mi-
croscope is applied to the examination of
the contents of water.

Ordinary examination of ivater. — Here it
appears merely necessary to point out that
the mode of examining the contents of sam-
ples of water, for the pui-pose of ascertaining
the extent to which organic beings are con-
tained in them, should be very diiFerent
from that pursued by the microscopist who
is engaged in collecting specimens. We
make this remark in consequence of the
gross misrepresentations which have been
made respecting the " animalcules " in
water, carried- to theu'most absurd extreme
in the so-called " drop " of water shown by
oxyhydrogen microscopes, where we often
see the field covered with larvas of dragon-
flies, of beetles, of gnats, &c., Entomos-
traca, and worms of diflerent kinds, not
only preceptible without a microscope, but,
in the case of the larva), perhaps really more
than an inch long. Less violent exagge-
rations occur when water which appears
cloudy is selected, allowed to stand for some

WATER.

[ 816 ]

WEISSIA.

time, and the sediment examined. Very
false results must also be obtained when
water is exposed to tlie air for any length
of time before examination, since Infusoria
and microscopic Algte always appear in a
short time, even in distilled water, when
exposed to the atmosphere; and an un-
covered water-butt or cistern wiU be foimd
a very fertile source of microscopic objects.
We regard the presence of most of those
organisms which do not sufficiently affect
the water to render its impurity discernible
by the naked eye, as a matter of little con-
sequence. Large niunbers of Entomostraca,
certain Ilotatoria and Infusoria, and Oscil-
latoriaceous Alga3, generally very perceptibly
clouding or colouring the water, of course
indicate the presence of much decomposing
organic matter in the water, which, how-
ever, reveals itself very clearly in a short
time when the water is kept, by a fetid
odoiu'. The presence of green Confervoid
Algfe is by no means a sure sign of impurity
properly so called, in water ; for some will
only grow in -sery clear and piu'e water,
while many of tliem may be regarded as
agents of purification. The presence of
Zygnemacese, Diatomacese, and especially
the Schizomycetes, is, however, particularly
objectionable, as they become very fetid in
decomposition, which generally takes place
very soon when they are distm-bed and
injured. When large numbers of minute
Algae appear in water, discolouring it over
extensive sm-faces, the microscope wiU en-
able us to detect the nature of the object pro-
ducing the appearance, but will scarcely be
requisite to prove the impurity of the water.

The mici'oscope is also of great importance
in detecting the presence of undigested and
bile-stained particles of food, showing the
admixture of sewage with water.

Coloration of iVfiter. — • Under this head
we shall refer to those plants and animals
which most commonly produce such ap-
pearances, premising that the commonest
cases of coloration depend upon suspended
mineral substances (mud), of tlitterentcolours
according to the soils wa^^hed by the water.

1. Producing a general f/recn colour, or a
thick film on the surface. — Protococcus
( C/damidonionas, Ehr., Diselmis, Duj. ), very
common in the spring ; and various Nosto-
chaceous Algfe, as Tiuchoemus, (.'oxio-
PHYTUM, &c. (see NosTocHACKiK ; many
with a bluish tinge); Cj.atiirocv.stis (form-
ing a granular verdigi'is-green layer), Mi-
ciiOHALOA, and various other Palmella-

CE^ and CoxFERVACE^ ; Euglena viridis,
See. The Desmidiace^e form greenish
patches at the bottom of water or on plants,
as do certain Oscellatoriace^b.

2. Producing a 7-ed colour in fresh water.
— Astasia hmnatodes, Ehr. ; species of
D.\piES'iA. TuBiFEx produces a red colour
on the mud in shallow water. Red forms of
species of Protococcus (see also Red
Snow). — In salt water, Diselmis Dunalii,
Duj.; Trichodesmium.

3. A brown cloudy appearance often ap-
pears in masses near the source of small
springs of water flowing out of blue clay,
or in pools on peat-bogs. This mostly con-
sists of peroxide of ii'on ; but sometimes a
similar brown appearance is produced in
pools by collections of amorphous granular
decaying organic matter, in which occm*
great abundance of certain Oscillatorle,
l)iATOMACE^,IxFrsoRiA, and Rotatoria.
The obscure mycelioid sti'uctm'e called by
Kiitziug Leptothrix ochracea produces a
yellowish-brown tiut ; Didymohelix also
gives abrown colour to water. Diatomaceae
often form a yeUowdsh-browu coat on mud
at the bottom of water. Many Rotatoria
and the larger Infusoria (Paramecia, &c. ),
when abundant give water a slightly milky
appearance.

The ordinary method of separating the
organic bodies from water, is to place it in
a conical glass, and allow them to subside.
A httle spirit or osmic acid shoidd be pre-
viously added fo prevent growth or repro-
duction. The bodies are then removed
with a pipette, or separated by filtration
thi'ough hwedish paper.

The above list is undoubtedly very im-
perfect, but may afford some usefid hints.
Microscopists who meet with such colora-
tions will naturally examine them carefully;
tliey will find f lu tlier information under the
heads of the articles cited.

BiBL. Macdonald, Soc. Sci, Congress,
1877 ; Scott, Jn. Mic. Soc. 1877, Mn. M.
Jn. xviii. 237 ; Church, Water, 1877 ; Fox,
Food 4''C. 1881; Cohu, Beit)-, z. Biol, i,
108; Blyth, Food ^r. 1881; Frankland,
Water- Analysis.

WATER-B1:aRS. see Tarbigrada.

WEIJBI'NA, D'Orb; (Restricted.)— A
anhgewnSioi'J'rochainminu ; adherent, single-
celled, mouiliform, or alternating. Recent
and fossil.

JiiRL. Parker and Jones, Phil. Tr. civ.
4-35; P.,J., & Brady, ilfa?K)(/. Crag For. 25.

WEISSIA, Iledwig.— A genus of Pot.

WESTWOODIA.

C 817 ]

WHALEBONE.

tiaceous Mosses, variouslydefined by authors,
related to Gt/mnosfomum. W. controversa
(W. viridula, Miill.) is common on banks.
Wilson includes Blindia here, and separates
W. fuyux and denticulata as Rhabdoiveissia.
(W'ilmn, Bn/ol. Br. 4Q.)

WESTWOODIA, Dana, = Arpadicus
pt. W.nobilis = Arp.nob.jXn.'AY\)iQ. (Bradv,
Copep. ii. 140.)

WILALEBONE.— In whales the teeth
are rudimentary ; and arising from a depres-
sion ill the upper jaw on each side are a
number of parallel horny plates, many feet
in length, which proj ect downwards : these
plates, which are technically known as fins
or blades, constitute whalebone ; and through
them the water containing the animals upon
which the whale hves is strained, and the
food thus obtained. These plates are situ-
ated upon a vascidar membrane, folds of
which enter a cavity at their base, which is
the portion connected with the jaw.

Whalebone may be pretty easily divided
into longitudinal laminae and fibres ; but
these are oulj^ secondary forms resulting
fi'om the aggregation of a number of cells
of which whalebone wholly consists.

On examining a transverse section of a
blade or plate of whalebone with the naked
eye, or a lens, two structures are readily
distinguishable — an inner porous-looMng
medullary portion, surrounded by an outer
compact or cortical substance. A longitu-
dinal section through the plate exhibits a
number of dark lines or stripes, fi-om about
1-100 to 1-150" in diameter, parallel to each
other and to the axis of the plate, and cor-
responding to the pores seen in the trans-
verse section. These stripes, which have
been called whalebone-canals, but which we
shall denominate medullary lines, are seen
to be sun-oimded by a paler substance.

With a higher power {\ inch), the trans-
verse section exhibits in the centre a num-
ber of rounded apertures or circles con-e-
spondiug to the pores (PL 22. fig. 31), sui--
rouudedby very tine, concentric, interrupted
dark lines, whilst towards the cii'cumfer-
ence these lines run parallel to the surface
of the plate. In the longitudinal section,
viewed with this power, the medullary lines
are seen to consist of a number of cells
(PI. 22. fig. 30), mostly arranged in single
longitudinal series, and, in dried whalebone,
having a very dark appearance by trans-
mitted light, from the presence within
them of a large quantity of pigment and
air. These are the medullary cells. The

sing them

iug a transverse section

substance between the lines of medullary
cells exhibits very fine longitudinal strise,
and, in parts, the ends of divided laminae.

On macerating whalebone for twenty-
four hours in solution of caustic potash, it
becomes soft ; and on aftei-wards digesting
it in water, the cortical portion resolves
itself into numerous large transparent cells
from 1-230 to 1-310" in length, and fi-om
1-500 to 1-330" in breadth (PI. 22. fig. 33).
These contain a variable number of gra-
nules of pigment, of a deep brown colour,
also some small globules of fat, which are
especially numerous in those portions near-
est the base of the plate. These cells in the
natural whalebone are laterally compressed
or flattened : and the transverse axes of
those surrounding the medullary lines are
arranged tangentially to the latter, whilst
in the cortical portions these axes are par-
allel to the surface of the plate. The con-
centric lines seen in a transverse section
arise principally from the pigment-granules
within those cells which sui'round the me-
dullary cells becoming arranged in a linear
series by the flattening of the cells enclo-
This may be shown by treat-
of whalebone with
caustic potash, and then adding water and
watching its resolution into cells. As these
expand, the interrupted lines are seen also
to expand as it were, and to become re-
solved into a number of distinct pigmenl-
grauules existing within each cell. The
lines seen in a longitudinal section arise
from the miequal refraction of light by the
laminae of compressed cells surrounding the
medullary lines.

The medullary cells contain a large quan-
tity of pigment, as do also those compressed
cells which immediately surround them ; in
the former these grauides are frequently
aggregated. In the common dry whale-
bone of commerce the medullary cells also
contain air, which has been mistaken for
fat, and hence the cells denominated fat-
cells. The air is readily displaced by liquids.
Between the compressed ceUs, minute ca-
vities containing air, sometimes assuming a
linear form, at others representing mere
dots, are seen both in the transverse and
longitudinal sections ; these are distin-
guished by the displacement of their con-
tents. Hence ordinary whalebone closely
resembles hair or horn in its structure ; and
the fibres which are seen projecting from
the margin of the blades as found in com-
merce have a remarkable similarity to hair

3g

WHEAT.

[ 818 ]

WOOD.

(PI. 22. fig. 32). Chemically, it consists of
a proterue compound, and is therefore co-
loured by INIillou's and Pettenkofer's test-
liquids.

AMialeboue polarizes light like horn.
BiBL. Runiev, Phil. Trans. 1787; Bonders,
IlidcJer's Phys. Chemie ; Lehmann, Phys.
Cliem.

WHEAT.— The stabch of the grain of
wheat (Triticinn mlgare and other species
and varieties) presents itself in the form of
delicate little fiattish lenticular bodies, very
characteristic (PL 46, fig. 8). Wheat is
subject to various Blights, -which are re-
ferred to under that head, depending on
the groveth of parasitic Fungi, especially
TiLLETiA, attacking the ear, Pucci>^ia
attacking the straw, &c. In other cases the
ear is found infested with a minute worm
(Anguilli'la tritici) remarkable for its
tenacity of life.

WINGS OF Insects. — The arrangement
of the veins or nerves of the anterior wings^
of the Hymenoptera is sometimes used to
form the basis of systematic arrangement ;
and the several veins and interspaces have
received distinct names, which may be illus-
trated by reference to PI. 34. fig. 11, repre-
senting the anterior wing of the humble-
bee (L'otnbtts terrestris) : a, costal nerve ;
h, hind margin ; c, iimer margin of wing,
with the fold (k) for the attachment of the
hooks ; d, postcostal nerve ; e, externo-me-
dian;/, anal ; the nerve between 3 and 10, the
trausverso-median ; h, anterior or outer mar-
gin ; /, the subdiscoidal : s, stigma ; 1, costal
cell ; 2, externo-median cell ; 3, interno-
median ; 4, anal ; 5, radial or marginal ; 6,
first cubital cell ; vi, m, m, second, third,
and fourth cubital cells; 10, first discoidal
cell; 11, second ditto; 12, third ditto; 13,
first, and 14, second apical cell.
See Insects, ivini/s.

liiBL. That of Insects ; Jurine, Kou-
velle Methode ; Shuckard, Tr. Eniom. Soe.
i. ; Staveley, Miss, Neurafio/t, Linn. Trans.
xxiii. 125 ; Semper, Sielold c^ KiJUikers
ZAtischr. viii. 320.

WINTE'UE^.— A section of the Dico-
tyledonous family Magnoliacete (Dbiwys,
Tasmannia), remarkable for the character
of the elementary structure of the wood,
approaching closelj' to that of the Coniferpe,
It consists, as in that family, wholly of
pitted prosencliymatous colls without ducts,
the cells having two or three rows of bor-
dered pits as in Abaucabia. A distinc-
ion exists, however, in the character of the

medullary rays, which are very numerous in
Wintereae, occiuTing both large and small,
six or seven in the breadth of 1-12" in a
vertical section at right angles to the rays —
some of them being thin, composed of one
or two parallel layers of cells, extending to
a vertical extent of about ten cells, others
much larger, ten or twelve cells thick (or
broad), and of a vertical extent of eighty or
a himdred cells ; the latter are very evident
on the sm-face of the wood when the bark
is removed. The meduUary rays here tra-
verse all the annual layers of wood, which
is not the case in the Ooniferae.

BiBL. Goeppert, Linncea, xvi. 135 (1842) ;
Ann. Sc. Nat. 2. xviii. 317.

WOOD. — The mode of origin of Avood is
explained in the articles Cambium, Me-
dulla, Medullary Kays, and Vascular
bundles, while the characters of the ele-
mentary organs of which wood is composed
are described under the heads of Cell ;
Fibrous, Pitted, and Spiral Struc-
tures ; and Secondary Deposits. Pe-
culiar composition of the wood in certain
classes, families, or genera of plants is also
noticed under their special heads, which
will be referred to presently. In this article
the principal modifications of the wood, as
a whole, occurring in these and certain
other cases, are to some extent classified,
in order to indicate their relations, and to
furnish a guide to microscopists seeking to
observe the most remarkable varieties of
structure, occurring in this substance.

The elements entering into the composi-
tion of wood are : — 1, Fibro-a'ascular
bundles, which in their most complete
form contain Spiral and other Vessels,
Pitted ducts, Prosenchymatous cellular
tissue with thickened walls {looody Jibre) ;
and in the Monocotyledons, vasa propria,
as they are called by Mohl, viz. elongated
tubular cells of membranous structure oc-
curring in the centre of the bundles. 2,
Medullary Rays in the Dicotyledons, or
a generally diftused medullary parenchyma
in the Monocotyledons. 3, Woody I'AREN-
CHYMA, which is foimd under difterent con-
ditions and in difterent quantities in difter-
ent cases.

The GvMNOSPERMS may be considered
in the above enumeration as agreeiug with
the Dicotyledons. Tiie less-generiilly dif-
fused structures connected with Secretion
are here let^t out of \\e\\.

In classifying the kinds of wood, we may
commence with the l^ss perfect forme.

WOOD.

[ 819 ]

WOOD.

Monocotyledons. — In our uative plants of
this class the stem is mostly herbaceous,
and the woody structure then occius sim-
ply in the form of " fibres " (Jibro-vascular
bi'mdks, tig. 45G, p. 495), the structure of
which has been described elsewhere (fig.791,
p. 800). The same kinds of elements are
arranged in nearly the same way in must of
the arborescent plants of this class, such as
Palms — for example, in the Cocoa-nut Palm,
in the common Cane {Calamus), or the
various striped solid canes (all Palms) used
for walking-sticks, &:c. The solid woody
textm'e depends in these upon the inter-
space between the fibro-vascular bundles
being filled up with looody imrenchyma ; i. e.
the general medullary substance, which in
such stems as that of the White Lily is soft
and spongy, in the Palms &c. becomes soli-
dified by tlie great deposition of secondary
layers upon the walls of the cells ; thus
the bundles, at first ''fibres," are bound
together into a solid wood. The thick
woody walls of the hollow Bamboo cane
are constructed on the same plan, being
highly developed and lignified forms of
the structure which is exhibited in a soft
and herbaceous condition iu our common
Grasses.

Certain Monocotyledons present a struc-
tm'e which differs from the above in the
appearance presented by transverse sec-
tions. In the Smilacese, and some of the
Dioscoreacese, the fibro-vascular bundles are
aiTanged in more definite order in one or
two cij'cles ; but there is no distinction of
pith, medullary rays, and bark here ; the
bundles are bound together by looody par-
enchyma, and there is no cambium-region
beneath the rind. The anomalous gTowth
exhibited by the stems of other Monoco-
tyledons, such as Draccena, Yucca, See.,
cannot be regarded as depending on the
formation of wood in the proper sense ; in
them, layers of fibrous structure tire formed
between the central region of the stem
(containing the original vascular bundles)
and the rind, which take their origin from
the ends of the vascular bimdles at the
periphery of the stem beneath the rind, and
extend down in a kind of false cambium
layer beneath the rind.

Interesting objects illustrating the above
structures arc furnished by longitudinal and
transverse sections of the trunks of large
Palms and of the large woody leaf-stalks of
these, of canes of difterent kinds, of Bamboo
canes, the rliizome of Sarsaparilla plants

(Smila.v), JRuscus, the harder parts of the
stem often found attached to imported
Pine-applos, &c. Sections of silicified fos-
sil Palm-stems, prepared by the lapidary,
can also be obtamed from the dealers in
objects.

Dicotyledons. — In this class we meet with
a remarkable diversity in the character of
the wood, which moreover here exhibits,
from the indefinite power of gi'owth of the
Fibro-vascular bundles, a much more
extensive and perfect development than in
the Monocotyledons. In the articles Me-
dulla (fig. 455, p. 495), Medullary Rays
(fig. 457, p. 496), and Vascular bundles
(fig. 792, p. 801) are described the condi-
tions of ordinary Dicotyledonous stems in
the first year of their growth ; it is stated
in the account of the vascular bundles, that
a new layer of wood is developed in the
cambium layer in each succeeding season
(fig, 457, p. 496). The nature of the ele-
mentary structures in such cases is illus-
trated by the accompanying figures from the
Maple {Acer campestre, figs. 807 & 808),

Fig. 807.

Traus verse and Tex-tical section of a segment of a
shoot of the Maple in the early pai't of the second year
of itsage. T. spiral vessels; YP, pitted ducts; F, woody
fibre; C, cambium; Pc, cortical parenchyma; F, liber
fibres; Pc, cellular envelope of the bark ; S, corky layer
of ditto. Magnified 6U diameters.

3g2

WOOD.

[ 820 ]

WOOD.

Fig. 808.

Transverse section of Maple-wood three years old.
The figures 1, 2, 3 indicate the annual rings of wood ; the
rest is bark. ?», medulla; /.spiral vessels; u, ducts ;
f, woody fibre ; c, cambium ; «ie,medullary parenchyma ;
I, liber. Magnified 40 diameters.

of wMcli the former represents sections of a
shoot at the begining of its second year,
when the cambium layer (c) is swelling,
the latter a shoot of three years' growth,
the portions belonging to each year being
indicated by the figm'es. The only difFer-
euce between the structures developed in
each succeeding season is the absence of a
layer of spiral vessels (medullary sheath, in
the first year) at the point where each year's
gi'owth commences. Here, as is seen, the
fcody of the wood is composed chiefly of
prosenchymatous cells (wood-cells or woody
fibre,/), with a few pitted ducts (v) near
the commencement of each annual layer ;
the medullary rays are narrow in this wood.
In the Hornbeam [Carpinus Betidus) the
wood is of very similar composition; the
wood-cells, however, are more thickened,
and the ducts exhibit a spiral marking ; the
annual layers are not very clearly defined in
sections under the microscope. This is the
case, again, with the excessively hard wood
of the Box (Bkxhs semper virens), which is of
analogous composition. The Birch (Betida
nlba) has the same structure. Other com-
mon timber-trees exhibit an additional
structui'e in their wood, namely masses of
looody parenchyma interspersed in various
ways among the ordinary prosenchymatous
structure of the wood. A very small quan-
tity of this occurs in scattered groups in the
common Oak {Quercus pedunctilata) ; here
also the ducts are very large, appearing as
open holes to the naked eye in cross sec-
tions ; the larger medullary rays are like-
wise very evident. In the Beech (Fagus
sylvatica) there is a small quantity of woody

parenchyma, but greatly thickened prosen-
chyma prevails ; the ducts are rather small ;
but the broader medullary rays are very
evident, appearing to the naked eye as
brown streaks in longitudinal sections. " The
Chestnut {Castama vesca) differs from this
chiefly in wanting the broader medullary
rays. In the Elm ( Ubnus campestris) the
prosenchyma is interposed between bands
of woody parenchyma and wide ducts,
which renders the distinction of the annual
layers obscure. The Walnut-tree has no
woody parenchyma ; the Apple- and Pear-
trees have alternate bands of prosenchyma
and woody parenchyma ; these exist, but
are narrower, in the Plum and Cherry. In
the wood of most of the Ijeguruinosee
(Eobmia, JJlex, Genista, Gleditschia, &c.)t]ie
woody parenchyma appears in bands of con-
siderable size ; but the walls of its cells are
less thickened than those of the prosenchy-
matous cells. Woody parenchyma occurs
extensively in Mahogany and Rose-wood,
producing a peculiar variation of colour in
the wood ; the large holes are the orifices
of the very wide ducts.

The wood of the Vo-plavs (Poptdus), and
Willows (Salix), has the prosenchymatous
cells little thickened. The Hazel (Corylus
Acelland), and the Alder (Alnus glutinosa),
present a peculiarity : the wood appears to
the naked eye to have broad medullary rays ;
but imder the microscope these rays are
found to be portions of the wood devoid of
ducts, intervening between segments with
closely-pitted ducts placed at particular
points in the annual rings. The Lime
{Tilia) and the Horse-chestnut (yEscidus)
have wood of soft texture, the prosenchy-
matous cells being only slightly thickened,
while tlie ducts are large and numerous
(these exhibit a spiral band, very evident in
the Lime). The wood of the Plane {Phi-
tanus occidentalis) has strongly marked
meduUary rays ; the prosenchymatous cells
are greatly thickened; and mingled with
them are very numerous ducts, and a small
quantity of woody parenchyma. The stem
of the Vine ( Vitis viniferd) has likewise
long and broad meduUaiy rays ; the wood
is composed of prosenchymatous cells, with
a spiral-fibrous deposit on their walls, while
the cells of the woody parenchyma are
devoid of this ; the ducts are very long, and
exhibit every gradation of form, from spiral,
reticulated, and scalariform to pitted ducts.
The various species of Clematis have strongly
marked medullary r^ys, and wood chiefly

WOOD.

[ 821 ]

WOOD.

composed of pitted ducts, as is the case also
ill the common Rose.

Ill many of the above trees, the wood
acquires a special peculiarity when it attains
a certain age ; the proseiichymatous cells
generally become more solid, year by year,
through the filling-up of their cavities by
the increasing thickness of the secondary
deposits on their walls : in the lighter-
coloured and .-softer woods, such as the
Lime, there is no distinct line of demarcation
between the older and younger part of the
ti'unk — the alburmun or sap-irood and the
duramen or Jieart-n-ood ; but in mnny cases,
as in the Ebony (Dwspjjros) , Lignum vitfe
(Guai'acum), to a less extent in the Elm,
Oak, Szc, the duramen assumes a remark-
able solidity and a deeper colour, so that
after a certain time the colours of the dura-
men and alburnum are very different. This
appears to arise from a chemical alteration
of the substance of the secondary deposits
of the prosenchymatons cells.

A great degree of regularity and agree-
ment of structm-e exists between the woods
of the Dicotyledons above mentioned. It
remains to direct attention to various kinds
which depart more or less from the type
thus selected.

In the various parasitical Dicotyledons,
such &.S, Lathrcea , Melampyrum, Cuscuta, &c.,
there is no layer of .spiral vessels con-e-
sponding vdth the medullary sheath ; and
in the Mistletoe ( Viseuni) only annular ducts
occur in this situation ; the wood in the
latter is largely composed of woody paren-
chyma, the cells of which are punctated, or
possess spiral-fibrous layers (figs. 665, 666,
page 712). The stem of J/yror?? »f/ro« also
exhibits some remarkable anomalies.

In the Bombacese (Bombax, Carolinea,
kc.) the mass of structure corresponding ,
to the wood is chiefly composed of mem- j
branous parenchymatous cells, with scat-
tered isolated prosenchymatons cells, and '•
large pitted ducts. The wood of Avicentiia is i
principally composed of large pitted ducts,
with naiTow mterspaces filled up with small
pitted parenchymatous cells.

The wood of theCactacefe {MammiUaria,
Melocadus) is composed of dotted ducts,
together with a kind of cell, apparently re-
ferable to parenchyma, the walls of which
have a remarkably broad spiral-fibrous band
(PL 48. fig. 7). the wood of the Casiiarincs
exhibits a cm-ious structure : it is composed
of long prosenchymatons cells, the walls of
which, together with those of the numerous

large ducts, have bordered pits (PI. 48.
fig. 2) ; while concentric lines of cellular
tissue appear at intervals in the cross .sec-
tion, consisting of plates of parenchyma
extending from one medullary ray to* the
next, and connecting them. The stems of
some of the Menispermaceae have likewise
concentric processes of parenchymatous tis-
sue. In the WiNTKEE^, a section of the
Magnohaceae, the wood is wholly composed
(with the exception of the medullary sheath)
of pitted prosenchymatons cells resembling
those of Araucaria (PI. 48. fig. 5), without
any ducts.

In certain families of Dicotyledons a
remarkable appearance arises from the ar-
rangement of the bundles in several circles,
almost as in the Monocotyledons ; but this
results in a veiy different kind of structure,
on account of the unlimited growth of the
cambium in Dicotyledons. Examples of
this kind of wood occur in the Chenopo-
diaceae, Nyctag-inaceae, Piperacefe, &c. In
Pisonia, which has been supposed to grow
in the same way, the result is a solid mass
of wood, composed of prosenchymatons cells
and ducts, with isolated perpendicular cords
of parenchyma (exactly the reverse of what
occurs in the Monocotyledonous stems).
The woods of Phytocrene and Nepenthes
may be further cited as offering remarkable
peculiarities.

It would exceed the space which we can
allow to this article to enter into a descrip-
tion of the anomalous Dicotyledonous stems
of the tropical lianes or climbing trees, of
the Bignoniace(S, 3Ienispermacea;, Malpighi-
ace(^, Sec. ; the irregularities of the wood
of which depend upon deviations from the
normal type arising in the course of the
growth of the stems, which, from the obser-
vations of Treviranus, Crtiger, and others,
appears to be mostly regular when quite
young. Isolation of one or more fibro-vas-
cular bundles from the central cylinder of
wood, producing distinct centi-es of develop-
ment, is the most common cause of irregu-
larity.

The wood of Dicotyledons must be exa-
mined by transverse sections, and pei-pendi-
cular sections parallel with and at ri^ht
angles to the medullary rays. The same
applies to the wood of Gymnosperms. The
mode of cutting these sections is stated
elsewhere.

Sections of recent woods are best pre-
served wet in chloride of calcium. Fossil
wood, if silicified, is cut by the lapidary's

WOOD.

[ 822 ]

WOODWARDIA.

wheel ; wood in the state of coal in like
manner (see Preparation, Fossil wood,
aud Coal).

Gymnospertns. — In this division of the
Flowering Plants Ave also meet with two
types of structure :

GonifercB. — Here the character of the
wood agi-ees in general with that of the
typical Dicotyledons, with certain distinc-
tions ; namely, althoui^h the medullary
sheath of spiral vessels exists, no ducts or
vessels occur in the mass of wood external
to this, which is wholly composed of pros-
enchymatous cells, with bordered pits, in
single (Plate 48. fig. 4) (usually), double, or
treble (Araucaria) rows (fig. 5) ; in Ta.rus
accompanied in part by a spiral-fibrous band
(fig. 4). The particulars of these forms are
given under Coxifer^. It may be men-
tioned that the " woody parenchyma " of
Dicotyledons seems to be represented here
by the cords of parenchymatous ceUs in
some cases traversing the prosenchyma, ulti-
mately filled with resinous deposits (" cords
of secretion-cells").

Ci/cadacece. — The earliest condition of
the stems here appears to resemble that in
Coniferse ; but no annular rings are formed.
Concentric layers are produced at intervals,
however, separated by parenchymatous
layers. The true mode of origin of these
does not appear to be clearly made out.
The wood is composed of pitted prosenchy-
matous cells (PI. 48. tig. 20), without ves-
sels or ducts, excepting in the medullary
sheath of spiral vessels.

Some elaborate and interesting researches
on the peculiar intimate structure of wood
and tissues have been published by Har-
ting, Sanio, Nageli, and Hanstein ; but we
have no space to analyze these long papers
here.

For further details on the markings of
the ducts, &e., see Pitted and Spiral

STRUCTURES.

BiBL. Lindley, 7nfo'. to Bot. ; DeCandolle,
Orgcmographie, i. 161 ; Meyen, Pflanzen-
phys. i. 331 ; Goeppert, Struct. Conifer.
1841, Linncea, xvi., xvii., Ann. Sc. Nat. 2.
xviii. 1 & 317 ; Brongu. Veyet. Fossiles, 1828,
et seq., Ann. Sc. N. 1. xvi. 589; Hooker,
Flor. Antarct., Ann. Sc. Nat. 3. v. 193 ;
Gaudichaud, Recherches Anat., and Ann,
Sc. Nat. 3. passim ; Meneghini, Ricerche
sulla Struftura Monoc. ; Schacht, Pflanzen-
zelle, 193, Das Baum, 94 ; Cruger, Bot. Zeit.
viii. 99, x. 465 ; Trdcul, Ann. Sc. Nat. 3.
xviii., xix., xx., 4. i., ii., iii. ; Milde, Beitr. z.

Bot. 1850 ; Hanstein, Pringsheim's Jahrb. i.
232; Sanio, Lvuidpa, 1858; Hartig, Bot.
Zeitumi, xvii. : Henfi-ey-:\Iasters, Bot. :
Sachs' Bot. ; Knv, Ilohkdrper, 1882.

WOOD'SIA, Brown.— A genus of Dick-
soniefe (Polypodiaceous Ferns), represented
by two rave indigenous species, W. Ilvensis
aiid hi/perhorca. Sori globose ; indusium
inferior, cup-shaped or globose, sometimes
enclosing the sorus, opening at the top, the
mouth or margin irregular, iobed or fringed
with long hairs (fig. 809). Several tropical
species. (Hooker, Syn. 46.)
Fig. 809.

Wodcl.^ia liyi.crborea.

A soma and indusiiua with a hair-like fringe.

Magnified .iO diameters.

WOODWAR'DIA, Smith.— A genus of
Blechnese (Polypodiaceous Ferns). Several
species; exotic.

Fig. 810.

hi

Itl^J

Woodwardia.
A fertile i>innule. l^Iagnifled 5 diam«ters.

WOOL.

[ 823 ]

XYLARIA.

WOOL OF Animals. See HAin. The

fibvt\s (if wool are coloured by the test-
liquids of Millou aud Schultze.

WRANGE'LIA, Ap-.— A peiius of Cera-
raiaceiie (Florideous Alga)), differing- from
Qrtffithmn chietly iu the scattered tetra-
spores. W. miilfiji'hi, the only Britisli spe-
cies, has rose-red feathery fronds, an inch
high, consistiug of a main filament, about
as thick as a bristle, composed of a single
row of cells, bearing long, pinnately-ar-
ranged, patent branches, mostly branching
in the same way again. At the articula-
tions occur two opposite (or more rarely a
whorl of) pinnato-multifid or subdichoto-
mous ramelli 1-1:^ to l-li" long. The fruc-
tification consists of: — 1, favellce, borne on
stalks at the joints, and surrounded b}' a
whorl of ramelli; and 2, elliptical fetra-
spores, opposite, secund or tufted, ou
the lower part of the ramelli. In some
foreign species antheridia have been ob-
served in similar situations to the tetra-
spores.

BiCL. Harvey, Mar. Alg. 169, pi. 24 D ;
Phyc. Brit. pi. 27 ; Derbes and Solier, Ann.
Sc. Nat. 3. xiv. 273, pi. 35 ; Thuret, ibid. 4.
iii. 38.

X.

XANTHID'IA.— The bodies found in
flint, and thus called, are probably sporangia
of Desmidiace* (PI. 25. figs. 22-28). They
have been distributed in genera and species,
the description of the characters of which
would be useless.

It is a curious circumstance, that these
sporangia should be found in flint, which is
of marine origin, considering that tlie Des-
midiacete are none of them marine.

XANTHIDTUM, Ehr.— A genus of Des-
midiacess,

Cliar. Cells single, constricted in the
middle ; segments compressed, entire, spi-
nous, with a circidar, usually tuberculated
projection near the centre. Spines more
til an two to each segment.

X. armatum (PL 14. fig. 23; fig. 24,
empty cell, showing the projections). Seg-
ments broadest at the base ; spines short,
stout, tri- or multi-fid ; length 1-180".

X. fasciculafum (PI. 14. fig. 25). Seg-
ments with from four to six pairs of subulate
marginal spines; central projections minute,
conical, and not beaded ; common ; length
1-400".

Sixteen .species.

BiBL. Ralfs, Br. Desmid. Ill; Rabenht.
Ah/, iii. 221 ; Archer, Prifc/iard's In/us.

XANTIIIOPYX'IS, Klir.-A genus of
fossil Diatomacete, consolidated with Pyxi-
DicuLA. It consisted of those species the
margins of the valves of which are furnished
witli a dentate membrane, or the surface
covered with seto^ or hair-like processes.
Bermuda.

BiRL. Ehr. Ber. Berl. ^A.w/. 1844, 2(34;
Kiitz. Sp. Alg. 23 ; Pritchard, Lifns. 82G.

XENOD'dCIlUS, Schlecht— A genus of
Urediuei (Flypodermous Fungi), con.sisting
of black tufts, found on the leaves of Pote-
rium, containing microscopic, short, curved,
usually shortly stipitate filaments, attenu-
ated at each end, composed of a moniliforra
row of (five to fifteen) globose cells filled
with black granules.

These bodies occur associated with TJredo
miniata, of which X. carhonarius appears to
be the perfect form. Xenodochus is only
distinguished from Phragaiidium by the
greater number of joints.

BiBL. Schlechtendahl, Li7incea, i. 237,
pi. 3. fig. 3 ; Fries, Sum. Vet/. 505 ; Ber-
keley, Ann. X. H. i. 263.

XENOSPHyE'RIA, Trevis.— A genus of
Micro-lichens, parasitic on the thallus of
Solorina saccata.

Char. Spores 6-8, oblong, 4-6-locular,
brown ; sometimes large, irregulai', and
muriform.

BiBL. Korber, Syst. 326; Lindsay, Qu,
Mic. Jn. 1869, 344.

XESTOLEBE'RIS, Sars. — One of the
CyiheridcB, with subtriangvdar valves,higher
behind than in front, smooth, with distant
papillse ; lower antennoe with 4 joints;
upper 6-jointed, with simple setje, and
short. Two living British species, com-
mon.

BiBL. Brady, Tr. Linn. Soc. xxvi. 437.

XIPHIAS'TER, Murray.— A genus of
Ixodea (Acariua). Flat, with a long pro-
jecting rostrum and long applied palpi ;
abdomen beaded behind. X. rostratum,
Old Calabar. (Murray, Ec. Entom. 201,

fig.)
XIPHICHI'LUS, Brady.— One of the

Cytheridce, near Parado.vostoma ; with sub-
equal, compressed-valves, elongate, pointed,
thm, aud smooth. Two living British spe-
cies, rare. (Brady, Nat. Hist. Tr. North.
S,- Durh. iii. 369).

X YL A'RI A, Schrank. — A genus of Sphae-
riacei (Ascomycetous Fungi), several of
which are common ou rotten wood, stumps

XYLEM.

r 824 1

YEAST.

of trees, &c. They are branclied, horny or
fleshy bodies, -with often clavate lobes,
whitish and mealy when j-oung', afterwards
brown or black, with black, homy, im-
mersed perithecia all over the branches, or
with the tips barren ; the perithecia have a
black centre composed of asci, each contain-
ing eight (usually uniseptate) spores.

BiBL. Berk. Br. Fl. ii. pt. 2. 234 ; Fries,
Sum. Veget. 381.

XY''LEM. — Nageli's name for the woody
tissue forming part of the fibro-vascular
bundles of stems. It is composed of spiral
vessels, woody fibres, pitted ducts, and
wood-parenchyma.

XYXOG'RAPHA, Fr.— A genus of Gra-
phidei, Lichenaceous Lichens.

Char. Apothecia black, linear, plane, in-
ternally ashy ; spores 8, simple. 4 sp., rare.
(Leighton, Lich. Flora^ 390.)

YEAST(-plant). — This well-known
substance, which possesses the remarkable
property of resolving sugar in solution into
alcohol and carbonic acid, consists of a mi-
nute fungus, or rather of a particular condi-
tion of development of a certain fungus.

When yeast from an actively fermenting
liquid is examined with the microscope, it is
seen to consist of myriads of minute cells or
vesicles, about 1-3000 to 1-2400" (PL 26.
fig. 23) in diameter, containing a nucleus
and some granules. During the progress of
the fermentation, these cells increase in
number, by budding, until either the sugar
or the nitrogenous matter of the fermenting
liquid is exhausted, when the cells, especially
those nearest the surface, become elongated,
remaining connected end to end, until they
reach the surface, where they produce their
fructification.

The growth of the yeast-plant has been
carefully studied by several observers. We
may describe some observations of our own,
which confirm those of Mitscherlich and
others. Some fresh wort, in which fermen-
tation had commenced, was obtained from a
brewery, and a drop of the liquid, containing
yeast-globules, placed upon a slide and co-
vered with a piece of thin glass. After the
removal of the extraneous liquid, the upper
glass plate was cemented to the lower one ;
the slide was then placed under the micro-
scope, with the l-4th object-glass -and the
micrometer eye-piece, in such a manner that
several well-formed globules were visible ;
and these were drawn on ruled paper.

At first the globules or cells enlarged imtil
they had attained a certain size ; then there
elapsed a short interval, during which no
change was observable. Next there took
place a projection of some point of the cell-
wall, which first appeared as a little point-
like bud, afterwards becoming larger and
larger, until at last a new cell, of the size of
the parent cell, was formed. Within three
hours a cell was so far developed that a
new one was formed from it, and thus an
independent individual perfectly developed.
The rapidity of gTOwth probably varies with
the temperature and the nature of the
process : in twenty-four hours, when the
thermometer was at about 78° in the day,
sixteen cells were developed from one. After
a time the growth slackened ; finally no fur-
ther increase took place, undoubted!}' be-
cause all was removed from the liquid which
could serve for their growth. Growing glo-
bules from this experiment are figured in
PI. 26. fig. 23.

Berkeley and Hoffman went a step further,
by contriving to get an atmosphere of air
round the drop of sugar and water, and
saw the cells of the yeast-fungus as soon as
it reached the air developed into a Peni-
cillinm.

By the observations of numerous compe-
tent investigators, it seems certain that the
fermentation of beer, of wine, and in fact
all vinous fermentation, is eftected by the
growth of this plant ; and after the evidence
brought forward in the articles Fermenta-
tion, ToRULA, and Vinegar-plant, there
is little doubt that the Vinegar-plant, the
Oidium lactis, and other supposed distinct
plants are but forms of the Yeast-plant.
PI. 26. fig. 24 exhibits the condition of the
Yeast-plant on the surface of exhausted
wort of malt, before the Vinegar -fungus
appears ; fig. 756, page 773, the Torula-iovm.
at the margins of the surface of liquids.

Wo cannot clearly make out any difference
between the 'top yeast' and 'bottom yeast'
{Oberhefe and tlnterhefe of the Germans),
beyond the difference resulting from more
or less active development : when the
growth is rapid the cells are more spherical
and become quickly detached, and the evo-
lution of gas comes up more to the surface ;
when the yeast vegetates quietly at the
bottom of the liquid, its cells are more
elongated. We do not believe the yeast-
cells ever burst to discharge reproductive
granules. The globular form is known by
various names, as Mycoderma cerevisife,

YEW.

[ 825 ]

ZOOSPORES.

Desni., which agrees with Cryptococcm ffhi-
fi/iis, Kiitz. ; the globular form in the Vine-
gar-plant is Kiitzing's Ulvina aceti; the
tilamontous form with simple moniliform
fruit (fig. 7oG) is Tontln cerevisice, Turpin ;
without fruit, species of Hygrocroch or Lep-
tomitus, tlie final form being apparently
PeniciUhnn r/laiicitm (PI. 26. fig. 15).

The Yeast-plant is truly most ubiquitous ;
but so are the conditions for its growth,
while its reproductive power is enormous,
and its small size renders it liable to be
scattered by imperceptible movements of
the air. Asperffilli(s (/laucus is almost as
constant in its' favourite nidus, cheese ;
Mticor mucedo on paste, &c. ; Botrytis vul-
yaris on dead leaves and stems in damp
places, iSrc. : and all these are certainly not
pseudomorphic productions ; and if, as we
believe really to be the case, yeast is but
the conidial form of PenicUUuin glmmnn,
there has been no lack of the spores of the
latter in the air, in any situation where we
have ever exposed vegetable substances for
any length of time to a damp atmosphere.

i^ees has lately observed in yeast, which
he calls Saccharomyces, that when sown on
plaster of Paris, or some convenient sub-
stance, certain cells at length swell and
contain sporidia. But after the fact that
sporidia are developed within the threads
of Chionyphe and in Hemileia, this does not
seem of much consequence.

The Yeast-fungus is often developed in
ripe grapes, causing -vinous fermentation.
In an article published in Aim. d. Sc. Nat.
the globules are regarded by Karsten as
merely pathological; but this is contradicted
by the facts above mentioned.

' BiBL. Turpin, Mem. de VInstitut, xvii.
93; Lowe, Tr. Edinh. Bot. Soc. 1857;
Bail, Flora, 1857, 417; Berkeley, Crypt.
Bot. 242, 299 ; Karsten, Ann. N. H. 4. xiii.
161 ; Rees, AlkohoIydhrimyspiJze, 1870 ;
Sachs, Bot. 254; and the BM. of Fermen-
tation.

YEW. See Taxtjs.

ZA'MIA, Liudl. See CYCADACEiE.

ZAN'CLEA, Gegenbaur. — A genus of
Corynidse, Hydroid Zoophytes.

Char. Stem simple or branched, rooted
by a creeping filiform stolon ; polypes more
or less clavate. Tentacles capitate, scat-
tered over the body ; gonophores borne on
the body of the polype and producing free
medusiform gemmae.

-The larval stage of some of the

Z. imple.ra, marine, on shells, stones, &c.

BiBL. Gegenbaur, Versvch eines Syst. d.
Medusen, Zeit. f. wiss. Zool. 1856,' 229;
Hincks, ITyd. Zooph. 58.

ZAUS, Goodsir. — A genus of Copepodous
Entomostraca. Two species, marine. (Brady,
Cope p. ii. 153.)

ZETES, Koch.— A genus of Arachnida,
of the order Acarina and family Oribatea.
It is consolidated with Galumna.

ZINC— The crystals of the lactate, as
deposited from an aqueous solution, are re-
presented in PL 11. fig. 20; they belong to
the right-rhombic prismatic system.

The chloride of zinc is useful as a preser-
vative of animal tissues. (See Preseeva-

TION.)

Chtm-iodide of zinc. See Schulze's Test.

BiBL. That of Chemistry.

ZOEA.-
higher Crustacea.

ZONARIA, Harvey (Aylaozom'a, Zanard,
Kiitz.). — A genus of Dictyotacese (Fucoid
Algse), of which the British species, Z. par-
vula, forms olive-green, membranous, fan-
shaped fronds, 1" or more in diameter,
growing over stones or corallines, to which
it attaches itself by whitish fibres on the
lower surface. It is scarcely marked with
concentric lines like Padina. The fructifi-
cation occurs in scattered sori on both sur-
faces, and is apparently analogous to that of
Padina, but requires further examination,
since Thuret has shown that the true Dicty-
otaceae have peculiar reproductive organs,
spores, tetraspores, and antheridia, so that
they stand between the Fucacete and the
Florideee.

BiBL. Harvey, 3far. Aly. 38, pi. 6 D;
Thuret, Ann. Sc. Nat. 4. iii. 25.

ZONOTRIC'HIA, Ag.=AiNACTis and
Euactis. (Rabenht. Aly. ii. 212.)

ZOOGLCEA, Cohn. See Bacterium.

ZO'OID. — The more or less completely
independent organisms, produced by gem-
mation or fission, whether these remain at-
tached, or are liberated and set free. (Ni-
cholson, Zool.)

ZO'OPHYTES, or Ccelenterata. See
Animal Kinc4Dom, and Polypi ; also
Hamann, Organism. Hydroidpolypen, 1882,

ZO'OSPORES.— The name given to the
ciliated active gemmoe orGoNiDiA produced
either singly or, more frequently, after
segmentation, in numbers, out of the con-
tents of oi'dinary or special cells of the Algae,
without any previous process of fertilization.
These bodies are generally discharged from

ZOOSPORES.

[ 826 ]

ZOOSPORES.

the parent cell in the state of Primoedial
Utricles, and acquire a cellulose coat
subsequently, wheu they cease to move,
and settle down to germinate and produce
a sti'ucture resembling the parent. In some
cases (in Hydrobictyon normally, in many
other Coufervoids abnormally) they become
encysted ■within the parent cell ; and it ap-
pears most probable that the small cysts with
dense and often spinulose coats, such as
occiu- in Sjnroc/yra (PI. 9. tips. 24, 25) and
other genera under certain circumstances,
are of similar origin. In the Volvo cine^,
zoospore-like bodies form the permanently
active individuals of the fomilies.

True zoospores occur pretty generally
throughout the Confervoid Algse, with the
exception of Oscillatoriacefe, Nostochaceae,
and perhaps Diatomacefe, and are described
under the heads of the families or genera.
A brief review may be permitted here. The
largest form is that produced in the apices
of the filaments of Vaucheria (fig. 796) ;
it is ciliated all over, and very unlike that
of any other genus. In CEdogonium (PI. 9.
fig. 7 c, k fig. 811) the zoospores are formed
out of the whole contents of a cell, and have
a crown of cilia aroimd the transparent
'beak.' In other Confervaceee, asClado-
pJiora (PI. 9. figs. 1.3 i,c'), Covferra (&gs.
10 6, lie); in Chpetophoracefe, as in
C7ieetnp/tora (fig. 9), Draparyialdia (fig.
180, page 271), Stujeoclonimn (PL 9. fig.
.5cc); in Ulvaceae, Viva (PI. 9. figs. 2 6,
Zc,d), Enferomorpha (tig. 4 6): in Froto-
coccus (PI. 7. fig. 2 6), in Achlya, in Desmi-

Fig. 811.

h

Zoospores of (Edofjonium. a have lost their cilia ;
and in 6 germination is more or less advanced. Mag-
nified .300 diameters.

diacefe (PI. 10. fig. ll), &c., as in all other
cases, they are formed either singly from
the entire contents, or in small or large
number by the segmentation of the entire
contents, and mostly break out in various
ways, as pyriform bodies with tAvo or four
cilia on the transparent beak, moving ac-
tively for a time, and then germinating to

produce new plants. They appear usually
to be surrounded at the moment of discharge
by a delicate common .sac, composed of
cellulose, which expands and quickly dis-
appears, apparently by solution, setting them
free ; in PEDiASTRrii, however, this enve-
lope appears to be permanent and to hold the
gonidia together in the characteristic group
or family (PL 10. fig. 11). In Hydrobic-
tyon, as de.scribed under that article, their
histoiy is different, though the earlier con-
ditions are analogous. It has been found
that zoospores of two very different sizes
are produced in many Coufervoids: these are
called macror/07iidia and mkror/on dia by
Braun(see Hydrodictyon) ; and a different
function is supposed to be exercised by the
latter by some authors, who believe they are
fertihzing bodies (like Spermatozoids).

Zoospores exist in a large proportion of the
Algae usually included under the Fucoide^,
but which Thuret separates under the name
of Phfeosporeae. The Phseosporeae have
sporangia containing motile zoospores, bi-
ciliated like the spermatozoids of the Mela
nosporeae (or Fucoideae). This separates
them from the latter. The Phaeosporous
families bear organs called Sporaxge.s
(usually described in Algological works as
spores), from which are discharged zoospores
agreeing in all essential respects with those
of the Coufervoids, except that the two cilia
are often arranged fore and aft, instead of
being both in front. Examples of these are
de.scribed under Ectocarpus, Myrionema,
CrTLERiA, Lamixaria, i.'cc. Zoospores
have been discovered in Fungi {Pcrono-
spora and Cystoptts) by De Bary, and in
Lichens by Famitzin : and if Saprolecjnicp
are really aquatic Fungi, their existence is
then notorious (PL 27. fig. 27). See Sapro-
legnia.

It remains to direct attention to the di-
stinction between Zoospores and Sper-
matozoids, which are sometimes confused
together. This confusion is rendered more
imminent by the manner in which i\\e. forms
pass one into another. The essential charac-
ter of a zoospore is, that when separated from
the parent, it usually becomes encysted and
at once developed into a new individual
resembling tlie parent. An exception to
this occurs in some of the zoospores of
(Edogoniuji, which, as the amlrospores,
produce special structures in which are de-
veloped spermatozoids. And in many cases
the zoospores conjugate, before becoming
encysted (Conjugation).

ZOOTEIRA.

[ 827 ]

ZYGNE]\rA.

Spermatozoids are transitory structures ;
when discharged from the parent cell, they
oither make their Avav to a germ-cell of a
spore, fertilize it and disappear, or, if de-
barred from this, at once perish without
germination. As stated under SpEn:\rATO-
zoiDS, these bodies vary much in form. In
the higher Cryptogamia they are spiral fila-
ments (PL 40. tigs. 31-4). In the Fucaceae
they are minute globular bodies with two
cilia (fore and aft) closely resembling some
zoospores ; in the Florideae they are globules
without cilia : and those recently described
as existing in VArcHEEiA, amoiig the Cou-
fervoids, are also biciliated globules with
the cilia fore and aft, while those in Sph^-
ROPLEiE resemble the microyonklin of this
family, having their pair of cilia on the beak ;
in CEcoGOxirM they resemble the zoospores,
but are smaller. The latter observation is
in favour of the microgonidia of Hydrodic-
tifon, &c. being spermatozoids.
■ ZOOTEI'RA, Wright.— A genus of Ac-
tinoplu-yina (Rhizopoda).

Char. Body furnished with numerous
contractile acuminate rays, elevated on a
contractile pedicel ; the rays become thick-
ened towards the point when not fully ex-
panded.

BiBL. Wright, Prifchard's Infusoria,
563.

ZOOTHA^l'NIUM, Ehr.— A genus of
Vorticellina (Peritrichous Infusoria).

Char. Body like Vorticella, usually of
different shapes, attached to the ends of
a branched zoary ; internal muscle branched
and continuous. Many s "
fresh water.

Z. arhuscula (PI. 32. fig. 22). Branches
of polypidconi racemose-umbellate, bodies
white, stalks very thick. Freshwater j
length of polvpidom 1-4" ; of bodies 1-430' '.

BiBL. Ehr. Infm. 288 : Stein, Inf. ; Clap.
& Lach. Inf. 101 ; Kent, Inf. 693."

ZOS'ENIE, Boeck. — A genus of Copepoda.
Z. typica, in dredgings. (Brady, Copepoda,
ii. 14.)

ZOS'TERA, L. -Agenusof Monocotyle-
donous Flowering plants (Nat. Ord. Zostera-
ceas), gi-owing in sea- water ; remarkable for
the Pollen, of which the grains are repre-
sented by tubular filaments destitute of an
outer coat and exhibiting Rotation when
fresh.

ZYGNE'MA, Agardh, in part {Tynda-
ridea, Bory, Hassall). — A genus of Zygne-
macese (Confervoid Algae), consisting of
filamentous plants, with the gi'een contents

pecies, salt and

[ of the cells an-anged in twin stellate or lobed
masses in each joint (fig. 137, page 204).
This stellate appearance arises from the
presence of radiating threads, like those from
the nucleus of SpiHOCiYUA ; hence it cannot
be well observed in dried specimens. Cell-
division with previous division of the
stellate masses may be well studied in this
genus. Kiitzing separates from this genus
all the forms in which the spore is formed
in the cross branch produced in conjugation,
associating them with Zyyoyonium. We
prefer to follow Hassall's distribution of the
forms, seeing that Zyyoyonium ericetorum
is a plant of very different appearance. If
the said character is constant, this genus
might be divided into two.

Spores in one of the parent cells.

Z. cruciata (fig. 137, p. 204). Filaments
1-GOO" in diameter; joints equal or twice
as long ; spores globose (Hassall, /. c. infra,
pi. 38. fig. 1 ; Kiitz. /. c. infra, y. pi. 17.
tig. 4). Z. Dilhvynii and stellina of Kiitzing
appear to be only smaller states of this, as
also Ty7id. lutescens, Hassall, and T.anomala,
Ralfs.

Z. staynalis. Filaments 1-2640" in dia-
meter, joints three or four times as long;
spores globose or oblong (Hassall, I. c.
pi. 38. figs. 9, 10). Tynd. ovalis, Hass., is
perhaps a larger form of this.

Z. insiynis. Filaments 1-1800 to 1-loGO"
in diameter, joints twice as long; spores
globose (Hass". /. c. pi. 38. figs, 6, 7 ; Kiitz.
/. c. V. pi. 17. fig. 1).

Z. bicornis. Filaments lr440 to 1-200"
in diameter, joints twice as long ; spores
globose (Hass. /. c. pi. 38. fig. 5 ; Kiitz. /. c.
V. pi. 16. fig. 3).

Spores in the cro.ss branches.

Z. immersa. Filaments 1-1200" in dia-
meter, joints about half as long again;
transverse processes very thick, filled by the
large and globose spore (Hass. /. c. pi. 39
fig. 3; Kiitz. /. c. v. pi. 12. fig. 5).

Z. conspicua. Filaments 1-1440 to
1-1080" in diameter, joints equal or twice
as long : transverse' processes long, ventri-
cose in the middle, where they enclose the
ovate-globose spore (Hass, /. c. pi. .39. figs. 1
2: Kiitz. I.e. v. pi. 12. fig. 2).

Z. decussata. Filaments 1-1440" in dia-
meter, joints three times (more rarely fiye
times) as long; transverse processes short

^.

ZYGNEMACE^,

[ 828 ]

ZYGODESMUS.

and filled by the globose spore (Hass. /. c.
pi. 39. fig. G : Kiitz. /. c. \. pi. 11. fig. 4).

Z. Unlfsn. Filaments 1-1920 to 1-1440"
in diameter, joints three or four times as
long; transverse processes very ranch dilated
in the middle, containing an elliptical spore,
with the long axis at right angles (Hass.
I c. pi. 39. figs. 4, 5 ; Kiitz. /. c. v. pi. 11.
fig. 2).

Z. pectinata. Filaments 1-G60" in dia-
meter, joints equal or a little shorter; cell-
contents transversely bipartite, more fre-
quently radiato-dentate, pectinate, dull
green (Kiitz. L c. v. pi. 14. fig. 4 ; Em/. Bot.
pi. 1611 ?). Possibly this is only a state of
Z. cruciata with the spores in the transverse
processes ; if so, the subdivision above indi-
cated cannot stand.

BiBL. Ilassall, Ahjce, 160, pis. 38, 39
{Tyndaridea) ; Kxitz. {Zygnema and Zygo-
yonium, in part), Tab. Phyc. v. pis. 11-17,
Sp. Air/, pp. 444, 445 ; Eabenh. Aly. iii.
248 ; Cooke, Alf/cs, 1882.

ZYGNEMA'CEyE(Pl. 9.figs. 16-28).— A
family of Confervoid Algae, consisting of
plants composed of articulated cylindrical
filaments, the cells of which often have the
green contents arranged in elegant patterns.
The principal mode of reproduction, whence
the family takes its name, is by Coxjuga-
TION, followed by a mixture of the entire
contents of the united cells, and their con-
version into a spore. Other phenomena
occur in some instances, such as the produc-
tion of ciliated zoospores, and small spore-
like bodies with a dense spinidose coat
{asteridia) ; but these appearances are not
yet thoroughly understood (see Spieogyea
and Mougeotia).

The British Genera are : —

Spiroyyra. Filaments simple, with the
green contents arranged in one or more
spiral bands upon the cell-wall. Conjuga-
tion normally by transverse tubidar pro-
cesses ; spores formed in one of the parent
cells (or occasionally in both).

Zr/ynema. Filaments simple, with the
green contents arranged in two globuLar or
stellate masses in each cell. Conjugation
by transverse processes ; spores formed in
one of the parent cells, or in tlie cross
branch.

Zyyoyorthnn. Filamentssimple, or slightly
braiiclied, with the contents dilTused or
arranged in two transverse bands. Conju-
gation by transverse processes ; spores glo-
bose, formed in the cross branches, or in
blind lateral pouches without conjugation.

Mesocarjms. Filaments simple, with the
contents diffiised. Conjugation by trans-
verse processes, from which the filaments
become recurved ; spores in the dilated
cross branches.

S/mirocm-pus. Filaments simple, with
the contents diffiised (or rarely in monili-
form lines). Conjugation by transverse
processes, from which the filaments become
recurved ; spores (or sporauges) square or
cruciate, in the dilated cross branches.

Movyeotia. Filaments simple, soon bent
at intervals, contents mostly diffiised, some-
times in several serpentine lines. Conjuga-
tion by the inosculation of the filaments at
the convexity of the angles; spores not
satisfactorily known.

Thwaifesia, Montagne, resembles Zyynema
in its stellate cell-contents ; but the spore
formed in one of the parent cells divides
into four portions (perhaps not distinct from
Zyynema).

Craterospermum, nearly resembling
Sfaurocarpus and Mouyeotia, but with the
spore and the short tube in which it is con-
tained subconstricted in the middle.

Pleurocarpus. Simple filaments, with
diffused contents, the conjugation taking
place between adjacent cells of the same
filaments, by means of a short arcuate tube ;
spore globose, in the tube.

Rhynchonema, Kiitzing, has spiral cell-
contents like Spiroyyra, but conjugates like
P/eiirocarpus, by an arched tube connecting
adjacent cells of the same filament.

BiBL. Kiitzing, Spec. Aly., Tabid. Phyc. ;
Braun, Ak/. IJniceU. 60 ; Eabenh. Alg. iii.
110 ; Cooke, Alyce, 1882.

See also the genera.

ZYGOC'EROS, Ehr.— A genus of Dia-
tomacese. Detached frustules of Bid-

DULPHIA ?

BiBL. Ehrenbevg, Abh. Berl Ak. 1839,
131 ; Kiitzing, Bacill. 138, and Sp. Aly. 139 ;
Rabenh. Alq. i. 310.

ZYGODAC'TYLA, Brandt.— A genus
of Campanuliniflfe (Hydroid Zoophytes).

Char. Capsules with an operculum formed
by many convergent and acuminate seg-
ments; polypes cylindrical, tentacles
webbed below; reproduction by free me-
dusiform gemmae.

Z. vibrina, Ilfracombe. (Ilincks, Brit.
Zooph. 191.)

ZY(K^DES'MUS, Corda.— A genus of
Sepedoni.ei (Hyphomycetous Fungi). Z.
fuscus occurs upon bark of fallen branches.
Berkeley thinks it-^possibly may be a form

ZYGODON.

[ 829 ]

ZYMOMES.

of some Thelephoroid Fungus. Currey has
shown that Corda's figure (fig. 812) is not
completely accurate, since he finds the

Fig. 812.

Zygodesmus fuscus.
Magnilied 400 diameters.

points at the apex of the fertile pedicels
each crowned by a spore ; and the normal
nimiber of sterigmata is probably four, so
that the structure would resemble a basi-
dium of Hymenomycetes. The above figure
is after Corda.

BiBL. Berk. Crypt. Bot. 298; Currev,
Micr. Jn. v. 126.

ZYG 'ODON, Hook, and Taylor.— A genus
of Orthotrichaceous Mosses, deriving its
name i'rom the yoking of the teeth in pairs ;
the species are mostly found in mountainous
districts and rarely in fruit.

ZYGOGO'NIUM, Kiitz. — A genus of
ZygnemaceDe (Confervoid Algae), consisting
of filamentous plants, growing on damp
groxmd or in water, gTeen or yellowish
when fresh, purple or bro'^Tiish when dry.
Kiitzing includes here all Hassall's species
of Tyndaridea (Zvgxema) which produce
the spore in the cross branch.

Z. ericetorum, Kiitz. Filaments 1-2160
to 1-1440" in diameter, joints as long or half
as long again, cylindrical or torulose (fila-
ments sometimes slightly branched). Con-
jugation rare, apparently mostly 'chain-like,'
from one cell to the next in the same fila-
ment. Contents green when growing in
water, purple when growing on wet heaths
(Hass. pi. 41; Greville, Sc.CrypL Fl. pi. 261.
fig. 1). Conferva ericetorum, DiUw.

See Zygnema.

BrBi,. Hassall, I. c. ; Greville, /. c. ; KUt-
zing, Sp. Aly. 445, Tab. Phyc. v. pi. 10;
Enq. Bot. pi. 1553 ; Rabenh. Aly. iii. 251.

ZYGOMYCETES.— A group of Fungi,
in which conjugation takes place, corre-
sponding to the Conjugatas of the -Ugse, as
in the Mucoiini &c. (Brefeld, Schimmel-
pilze, 1872 ; V. Tieghem, An. Sc. N. 5. xvii.;
Sachs, Bot. 268.)

ZYGOSEL'MIS, Duj.— A genus of In-
fusoria, of the family Eugleuia.

Char. Form variable ; movement eflected
by two flagelliform filaments, incessantly in
action.

Z. nehdosa (PI. 32. fig. 28). Body colour-
less, sometimes globular, at others variously
expanded so as to become pyiiforni or
top-shaped, turbid from the presence of
numerous granules. Freshwater; length
1-1100".

BiBL. Dujardiu, Inf. 369; Kent, Inf.
417.

ZY'GOSPORE or Auxospore. — The
result of the union of conjugating Algse.

ZY'MOMES =MiCROZYMES.

THE END.

PlilNTKD UV TAYLOR AND !• KANCIS, KED LION COURT, FLEET STREET,

J: