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QUARTERLY J QURNAL

MICROSCOPICAL SCIENCE,

EDITED BY

EDWIN LANKESTER, M.D., F.RB.S., F.LS.,,
AND

GEORGE BUSK, F.R.C.S.E., F.R.S., F.L.S.

VOLUME IV.

With Allustrations on Wood and Stone,

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LONDON:
JOHN CHURCHILL, NEW BURLINGTON STREET.
1856

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QUARTERLY JOURNAL

OF

MICROSCOPICAL SCIENCE.

ORIGINAL COMMUNICATIONS.

Notice of some New Species of British FresH-WaTer
Diatomacex. By Wittiam Grecory, M.D., FRS.E.,
Professor of Chemistry.

Havine examined with some minuteness the fossil Diatoms
in the Mull earth and in the Glenshira sand, both of which
deposits yielded a very large number of species, I felt desirous
to compare with them the species at present living in our
waters. Accordingly I obtained, from various friends, gather-
ings from a great many different localities, both in England
and in Scotland. Those which I have been able to study with
some care, up to the present time, are almost all from fresh
water, and, postponing to a future opportunity an account of
the marine gatherings, | propose now very briefly to notice
the results obtained from a number of fresh-water gatherings,
more especially with reference to such species as are either
altogether new or new to Britain.

It is well known that in no department of Natural History
are the species, whether recent or fossil, so universally distri-
buted oyer the earth’s surface. All the more common species
are found, according to Ehrenberg, in his recent great work,
‘ Microgeologie,’ not only in the Arctic and Antarctic regions,
but under the Equator, between the tropics, and in the tem-
perate zones. but few forms seem to be characteristic of any
country or quarter of the globe. The remarkable genus Terp-
sine, and a few others, have not yet occurred in Europe, but
are found at widely distant localities in other parts of the
world. A very striking example of the wide-spread distribu-
tion of diatoms is that of a beautiful little Pznnularia, which
I first noticed in the Mull earth, and which Mr. Smith, who
shortly afterwards found it recent at Grasmere, named Pinnu-
laria latestriata, a name which | adopted instead of P. Hebri-
densis. 1 have since met with it in at least three-fourths of
all the gatherings I have examined from fresh water, although
invariably scattered. I could find no figure of this species in

WOre Ty: B

2 DR. GREGORY, ON SOME NEW SPECIES

any work to which I had access, neither in Ehrenberg’s Atlas
of 1838, in Kiitzing, nor in Rabenhorst. Nor did any English
observer know it. But I now find that Ehrenberg had de-
scribed it as P. borealis ten or twelve years ago, although his
figure, which, if published, appeared in the Berlin Transactions
or the Berlin Monthly Reports, was entirely unknown to all
our authorities in this country, none of whom, more than my-
self, have been able to consult Ehrenberg’s very numerous
papers on the Berlin Transactions, or Monthly Reports, except
as quoted by Kiitzing or Rabenhorst, neither of whom noticed
this species. I mention these facts, to explain how it was,
that a species long ago described, and I believe figured, by
Ehrenberg, was regarded by all our authorities as new when I
found it in the Mull earth two years ago. And now I find, in
Ehrenberg’s Microgeologie, not only that the species is com-
mon, which, so far as concerns Britain, I had myself noticed,
but that it is one of two specified by him as occurring in every
latitude and in every quarter of the globe, more uniformly
than any others.* The fact, that it so long escaped notice in
this country is explained by its occurring always scattered, and

* The two forms named by Ehrenberg are Pinnularia borealis and
Eunotia (Nitzschia, Sm.) amphiowys. Having lately examined about
60 small specimens of earth, found attached to plants in the University
Herbarium here, and given to me by Professor Balfour, I find, in accord-
ance with what is stated by Ehrenberg, that every one of these specimens
of earth, which are chiefly from different parts of South America, contains
diatomaceous exuvia, and many of them in considerable quantity. I have
detected, in examining only one slide of that part of each earth which is
insoluble in acids, not only Diatomacez, to the extent of from 20 to 40
or even 50 species, in each case, most of which are identical with British
forms, but also spicule of Sponges, and many Phitolitharia, exactly as
Ehrenberg has done in the numerous similar earths analysed by him.
It is most remarkable, that the two species above named occur in at least
four-fifths of all the exotic earths I have yet examined ; and one of them,
P. borealis, in very nearly the whole of them. I may add, that I seldom
explore a fresh-water gathering at home without finding one or both of
these two species. Sufficient attention has not yet been paid to the fact
of the invariable presence of Diatomacex, &c., in all earths in which plants
are found. Ehrenberg, in his ‘ Microgeologie,’ has established the fact as
an universal one, and pointed out the important bearing it has on the
growth of the soil. Indeed, it is difficult to imagine a more effectual agent
in the transference of silica from the waters to the solid earth, than the
growth of Diatomacex, the shells of which are as indestructible as their
multiplication is rapid. Ehrenberg is of opinion that they live in the soil,
as well as in water, and the constant presence of moisture in the soil
renders this conceivable. Although the proportion of silicious matter,
dissolved in ordinary water, is but small, it is evidently sufficient to
supply the shells of millions of Diatoms in a very short time; and it is
therefore probable, that as fast as it is extracted from the water by them,
it is dissolved from the rocks or earths in contact with the water; so that
the supply never fails.

OF BRITISH FRESH-WATER DIATOMACE. 3

never, as many other forms do, in crowds together. But this
consideration shows the necessity of minute search, without
which many of the scattered forms would escape observation.
Many similar examples might be adduced.

It would be intolerably tedious to give a list of all the species
observed in these gatherings, of which I have examined, more
or less minutely, upwards of 200. I may state that, with few
exceptions, I have met with all the known British fresh water
species, and that I have found various new localities for many
rare and curious forms.

Few, if any, of the new species which have occurred, are
confined to one locality; most of them have been found in
several and these widely distant stations.

These new species may be conveniently arranged in three
sections: 1. Those already described by foreign naturalists,
but now first detected as British forms, 2. Those which,
although I have myself recognised them as entirely new forms,
have been also, either about the same time or subsequently,
observed by others. Although these are still unpublished MS.
species, and in many cases, my own observations were by
much the earliest, yet as I find that these forms have been
named by Mr. Smith, I adopt his names, to avoid the confu-
sion arising from synonyms. 3. Species which, so far as I
can discover, have nowhere as yet been described or figured.

I. Species, now first found as British, but known to foreign
authors.

1. Eunotia tridentula, Ebr., fig. 1, Pl. 1.*—Banffshire, R.
Findhorn.

2. Navicula follis, Ehr.—Lochleven, (qu. ? Trochus ?)

3. N. dubia, Kiitz.— Elgin, Lochleven.

4, N. bacillum, Ehr.— Lochleven.

5. Pinnularia nodosa, Kiitz. (Legumen, Ehr.)— Elgin,
Elchies, &c.

6. P. megaloptera, Ehr.—Benrinnes, Elgin.

7. P. dactylus, Ehy.—Benrinnes, Elgin.

8. P. pygmaea, Ebr. (Nana, W. G.)—Near Edinburgh.

9. Stauroneis Legumen, Kiitz.—Elgin, R. Findhorn, Dud-
dingston Loch.

10. S. ventricosa, Kutz.—Elchies, Elgin.

11. Cocconema cornutum, Ebr. ?—Lochleven.

12. Gomphenema subtile, Ehr., Elgin.—Glenshire sand.

13. Meloma distans, Ebr. (Gallionella)—Elgin, Elchies,
Lochleven.

I do not give these as in all cases absolutely distinct species,

* The species are numbered to correspond with the figures in Plate I.
B 2

4 DR. GREGORY, ON SOME NEW SPECIES

but only as the forms figured under the names here given by
Ehrenberg and Kiitzing. It is indeed probable that Pinnularia
megaloptera is only a long form of P. costata (lata, Sm.) ; and
that NV. dubia may be a variety, as some believe, of N. firma,
although I am rather inclined to think that VV. amphigomphus,
Ebr. and WV. dilatata, Ebr., both of which occur in Lochleven
with NV. dubia, may be forms of one species with the latter,
but distinct from N. firma. For this reason, I have only
mentioned NV. dubia in my list. The remarkable form which
I have referred to NV. Bacillum, Ehr. is perhaps, as I find from
Ehrenberg’s ‘ Microgeologie, rather his NM. Americana, al-
though, to judge from his figures, these two form but one
species, It is also probable that Pinnularia Dactylus is only a
variety of P. major.

II. MS. species ; named by Prof. Smith, but unpublished.

13. Navicula apiculata, Sm.—Mull earth, Elgin, Dhu Loch,
in Glenshire.

14. N. rostrata, Sm.—Near Haddington, Lochleven; near
Oban, Linlithgowshire, Dhu Loch in Glenshira, Elgin; also
recently near Hamilton, and at Borthwick Castle.

15. WN. scutelloides, Sm.—Norfolk, Lochleven.

16. Mastogloia Grevillei (for the locality only), Lochleven.*

At one time I regarded Navicula scutelloides as one of the
innumerable varieties of Navicula varians, a form to which I
have lately directed attention, as showing the extent to which
shape and outline may vary on the diatoms, without materially
affecting other characters. But my friend Dr. Greyille has
suggested that the form in question is rather a Cocconeis, and
his opinion possesses much weight.

III. Species now first described and figured.
17. Cymbella2?} sinuata, W. G.—Dhu Loch in Glenshira,

* I give a figure of Mastogloia Grevillei, first observed by Dr. Greville
in a gathering from the Pentland Hills. I subsequently found it in my
Lochleven gathering, but not having then seen Dr. Greville’s species, I did
not at first recognise it. It is scarce on the gathering from Lochleven,
but will probably be found in abundance in some part of the lake, or in
some of the streams which supply it.

t I am by no means sure that this form is correctly referred to the
genus Cymbella. 1 at one time supposed it might be a Hunotia, or a
Pinnularia, or possibly a Gomphonema. But the general opinion among
those to whom I have shown it is that it comes nearest to Cymbella. It
is marked, however, as doubtful. Some have conjectured it to be an
abnormal state of some form, not specified. But it occurs in so many
localities, always with the same characters, that I cannot but regard it as
a normal and distinct species. Dr. Greville has recently met with it in
various gatherings from the vicinity of the Bridge of Allan, and I have
again found it in several from the neighbourhood of Hamilton.

OF BRITISH FRESH-WATER DIATOMACE:. 5

and Loch Etive, Argyllshire; R. Calder and R. Avon,
Lanarkshire ; Lochleven. Fossil in the Mull earth and Glen-
shira sand,

I have thus named the curious little form represented in
fig. 17. It is narrow, slightly arcuate, with rather square,
slightly expanding apices. On the generally concave side are
three rounded but gentle prominences ; the central one consi-
derable, the lateral ones, which are near the ends, very slight.
Strize conspicuous, sub-distant, about 20 in ‘001, not reaching,
or hardly reaching, the median line, which seems to be, as in
the known Cymbelle, a little nearer the ventral surface.
There is in most cases a blank space round the central nodule.
Length from ‘0008 to 0012 inch.

The characters of this species are very constant. It varies
somewhat in size, and a little also in the form of the apices,
which are in some less square than in others.

I first noticed it in the Mull earth, then ina slide mounted by
Professor Smith for Gomphonema gemmatum, the locality of
which was not given; then in the Glenshira sand, and subse-
quently in the other localities named. It has always been,
hitherto, scattered, and does not seem to have been yet found
in the spots where it grew. But it appears to be widely
diffused,

18. Cymbella turgida, W. G. Elgin—This pretty spe-
cies has only occurred to me, as yet, in one British gathering,
from a moss near Elgin, but 1 have seen it in two speci-
mens of soil from South America. It is short and broad,
the dorsal line almost perfectly circular, while the ventral one
is nearly straight. ‘The apices are acute, and somewhat pro-
duced. The two halves are very unequal, the dorsal being
very broad, the ventral remarkably narrow, Strize very con-
spicuous, strong and sharp, about 24 in 001. Length 002 to
‘0025 of an inch. Of the British Cymbelle, C. maculata
comes nearest to it, but differs in form, in the shape of the
apices, in striatum and in general aspect. In the Elgin gather-
ing the only one in which as yet it occurs, the species is very
uniform and well marked on its characters.

19. Cymbella obtusa, W. G.—This species occurs in
many gatherings; as Lochleven, those from Banffshire, from
Lanarkshire, Argyllshire, &c. Dr. Greviile finds it in one
from Braid Hills. It is rather small, with very obtuse apices,
and the striz are inconspicuous, much finer than in any of the
known species. I think I have seen it named C. Scotica,
but Professor Smith’s figure of that species, which accurately
represents a very common form, is very narrow and has ex-
tremely acute apices. Length ‘001 to -0015. Strie about

6 DR. GREGORY, ON SOME NEW SPECIES

36 in ‘001. I name this and the preceding species with some
hesitation, not that they are not well-marked forms, as may be
seen from the figures, but because the genus Cymbella, as well
as the allied one Cocconema, is not in a satisfactory state, and
requires a thorough investigation, in which the forms I here
describe must be considered. The same remark applies to
the next species.

20. Cymbella Pisciculus, W. G.—This form occurs in a
very interesting gathering from Norfolk, and Dr. Greville has
recently found it near Bridge of Allan. I have also lately
seen it in various gatherings, including that from Lochleven.
It is rather large, broad, and has somewhat square apices.
Length about (0016. Striz about 30 in ‘100.

21. Cymbella Arcus, W. G.—This pretty form I have very
recently found in two gatherings from the neighbourhood of
Hamilton. The ventral surface is straight, the dorsal highly
arcuate, and slightly undulating, broad in the middle, very
narrow towards the extremities, like a strung bow. The apices
are rather square, expanding a little, after a slight construc-
tion. The striz are best seen about the middle, where the
frustule is broadest. Length about ‘0014. Striz about 30 in
‘001.

22. Navicula cocconeiformis, W. G.—Occurs in Elgin,
Elchies, and some other Banffshire localities, and Lochleven,
and recently in various gatherings from different parts of
Scotland. In form it is short, broad, nearly oval, but with
a slight angularity in the middle, and flattened apices. Some
specimens are almost rhombic. In shape it comes very near
to Cocconeis flexella (Thwitesii), and it has much the aspect
of that form, except that the median line is quite straight.
Strie not resolvable. Length from ‘0006 to ‘0012. I under-
stand that this form has been named NV. nugax by Professor
Smith, but I consider my own name, given much earlier, as
more characteristic. Besides this, Dr. Greville has lately
figured it under the name here adopted.

23. Navicula lacustris, W. G—This fine species has only
as yet occurred in the gathering from Lochleven, in which,
though not abundant, it is yet far from scarce. It presents
two well-marked varieties, z and £, which pass into each other
by intermediate forms: a, which is rather more abundant than
the other, is elliptico-lanceolate, with acute apices. Nodule
bright in the centre, but without definite outline. Median
line double. Striz fine, but distinct, slightly inclined ; about
28 or 30 in, ‘001; length from 0016 to -0025 inch: 6 agrees
in every point with a, except in outline. It is broad, has
straight sides, sometimes even a little incurvated, and sud-

EE

OF BRITISH FRESH-WATER DIATOMACE. 7

denly contracted to narrow produced extremities. These two
varieties are seen in figs. 23 and 23, and there exists an
intermediate form. The only species with which this could
in any way be confounded is WN. firma, var. 6. But the
latter is longer and larger, always of a brown colour, and in
NV. firma not only are the strize much finer and less con-
spicuous, but they are almost exactly parallel. It is not easy
in a drawing to give certain peculiarities of aspect, but any
one who compares the two species, WV. firma 6 and WN. lacustris,
will perceive that the latter has an aspect entirely different
from the former, Moreover the side lines, always seen in
N. firma, never occur in WN. lacustris.

24, Navicula bacillaris, W. G.—This pretty little species
was first observed in several gatherings from Duddingston
Loch, and has since occurred in many others, as Lochleven,
Elchies, Elgin, and in large quantity in two from the neigh-
bourhood of Dundee. It is linear, narrow, with rounded and
slightly pointed apices. It has a very smooth aspect, and the
strie are so fine that it is difficult to resolve them, Length
from ‘0012 to :002 inch.

25. Navicula lepida a, W. G.—This form occurs in the
Lochleven gathering, where it is not rare, and I have recently
seen it in others, as in those from Hunter’s Bog, and in
one of Dr. Balfour’s from Borthwick Castle.* It is small,
of a narrow oval, and has at first sight a smooth polished
aspect; but on closer inspection the striz are seen to be by
no means very fine, but rather difficult to catch from their
transparency. They are distinctly but slightly radiate. The
central nodule is indefinite, and assumes frequently the aspect
of a hazy cross-band, approaching to that of a false stauros.
It is a very neat and well-marked little form, and its characters
are very constant, varying considerably only in length; the
average being about ‘0015 inches.

258. Navicula pileda? 6, W. G,—This is another small
form, which in some points is so near the last, that I regard it
for the present as a variety of NV. lepida. It is small, of a very
short oval shape, and the strie are both more distinct and
more radiate than in J. lepida, but yet it exhibits at first
sight the same apparent absence of striation. The difference
is in the structure of the nodule, which in the present case is
always very definite, transparent and glassy ; the same peculiar
aspect is seen in the terminal nodules; this form hardly ever
varies even in length. I have only once seen a specimen a
good deal longer and narrower in proportion, and consequently

* Dr. Greville has also found it in a recent gathering from Duddingston
Loch (April, 1855).

8 DR. GREGORY, ON SOME NEW SPECIES

in form close to WN. lepida, but the nodule retained its charac-
teristic aspect

26. Navicula incurva, W. G.—This elegant species 1 have
observed in two or three gatherings from the River Findhorn,
and very sparingly in that from Lochleven. It is rather
narrow, with somewhat angular shoulders, contracted suddenly
towards the apices, which are produced and square, and
more gently towards the centre. Length about ‘0017 inch.
The strie bave not yet been resolved. It seems to belong toa
group, all of which have irresolvable strie, such as NV. producta
and LV. affinis ; but its very characteristic and constant form
render it quite distinct.

27. Navicula longiceps, W. G.—This little form occurs in
the Morayshire and Banffshire gatherings along with the equally
minute species Pinnularia linearis, P. subcapitata, P. gracil-
lima, and WN. bacillaris. It is small, linear, narrow, but net
very long, contracted near the extremities, and subsequently
continuing of uniform width to the broadly rounded apices.
Nodule indefinite, striae not yet resolved. Length about ‘0012
inch. It is more frequent in the Elchies gathering than in
any of the others, and is very permanent in its characters. |
have named it, from the peculiarly long shape of the con-
tracted ends.

28. Pinnularia biceps, W. G.—This well-marked form
occurs in the gatherings from Elgin, Elchies, and Lochleven,
as well as in some others, and is by no means rare. It is
rather large, linear, contracted towards the ends, and expand-
ing into large round heads. The striz which have, as in P.
divergens, three centres of radiation, do not reach the median
line, and towards the central nodule leave a large round blank
space, on the sides of which of course the striae are much
shortened. There are two varieties: 8, which is less con-
stricted and subcapitate; and y, which has three undulations
on each side, and is capitate like the type. Length from ‘002
to 008 inch. Striz about 24in ‘001 inch. This species ap-
proaches to P. divergens, which, however, is not capitate, and
besides has the central blank space in the form of a broad
false stauros, reaching to the margin, so that there are no striz
on either side of the central nodule.

29. Pinnularia linearis, W. G.—This little form occurs in
the gatherings from Elgin, Elchies, and several other Banff-
shire localities, also in Lochleven and elsewhere. It is small,
linear, narrow, very slightly narrower at the apices, and occa-
sionally a little contracted just before them. The stria are
fine, very nearly parallel, reaching the median line. Nodule
small, somewhat elongated; it has a distinct border, formed

OF BRITISH FRESH-WATER DIATOMACEZ. $

apparently by a line parallel to the outer margin, and this
border is very broad for so small a form. Length from ‘001
to ‘0012. Striz about 40 in -O01 inch.

30. Pinnularia subcapitata, W. G.—This is another small
and linear species, which is found in the same gatherings as
the last, and also P. vaciva. It is linear, narrow, constricted,
subcapitate, the ends rounded. The striz are subdistant, con-

“spicuous, short. Length about 0013”.

31. Pinnularia gracillima, W. G.—This species occurs in
the Elgin and Elchies gatherings, in others from Banffshire,
and in various other localities, It is, I believe, the same
as that which Mr. Smith has named P. vaciva; but I had
named it long before, and as Dr. Greville has adopted my
name in a recent paper in the Annals, I retain it. It is very
narrow and long in proportion, varying a good deal in length,
as from ‘0014 to -0025. It has a constriction towards the
apices, which again expand into longish rounded heads.
Strie fine but distinct ; I have not counted them. Dr. Greville
has found this species in the district of the Tummel and
elsewhere.

32. Pinnularia digito-radiata, W.G.—This species occurs
in several gatherings from Duddingston Loch, also in Loch-
leven and elsewhere, and is not very rare. It is rather small,
in form linear elliptic or elliptic-lanceolate, and somewhat
narrow. It has a delicate aspect, and the striz are dis-
tinct, though rather fine, except at the centre, and much
inclined, The central nodule expands a good deal laterally,
and from it on each side diverge five or six very strong striz
or coste in a digitate fashion, as may be seen perhaps a little
too strongly marked in fig. 32. This character comes out
well under a high power. Length from ‘0014 to ‘002 inch.
Sirie about *25 in‘001”. This species has some resemblance
to the more finely striated varieties of what I have named
N. varians. But as N. varians occurs along with the new
form they are easily compared, and it is seen that the striation
of NN. varians is much coarser and far more conspicuous, so
that the aspect of the two forms is quite different.

33. Pinuularia Elginensis, W. G.—This species is another
of the numerous capitate forms which occur in fresh water.
It is rather small, not very narrow, with straight sides, con-
tracted towards the extremities, and again expanding into
somewhat square truncate heads. The nodule is rather inde-
finite, the striae not conspicuous but easily resolvable, fine and
very slightly radiate or inclined. It may possibly be a Navi-
cula, but it is often very difficult to know to which of these
two allied genera, Navicula or Pinnularia, we ought to refer a

10 DR. GREGORY, ON SOME NEW SPECIES

species. It seems to be distinguished by the character of its
striation from all similar forms yet described. NV. varians
sometimes takes nearly the same outline, but is at once known
by its conspicuous and highly radiate striaz. Length about
‘0013 inch, Striz about 30 in -001”.

34. Pinnularia globiceps.—This elegant little form occurs
not unfrequently in a very beautiful gathering from Norfolk,
the same in which I first noticed Cymbella pisciculus. 1 have
met with it also, or at least a form much resembling it, in the
recent mud from the Dhu Loch in Glenshire. It is well
marked by its globular extremities and prettily curved outline,
swelling a little at the middle part. The terminal nodules
are very prominent, casting a shadow, the central are indefi-
nite. The striz are fine but sharp and distinct, not reaching
the median line. They have three centres of divergence, and
are entirely absent from a broad crucial space, like a large
false stauros, the upper and lower parts of which pass into the
long blank caused by the striae not reaching the median line.
In fact the arrangement of the striz and blank space is like
what we see in P. divergens, Sm. Towards the apices the
blank space expands again. Length ‘0014 inch. Striz from
36 to 40 in 001”. It is possible that this form may be allied
to P. Stauronetiformis, or to P. divergens, as it is also possible
that the two last named may belong to one species. ‘The name
must therefore be considered as provisional for the present.
In any case it must be distinguished as a striking and well-
marked form, even if only a variety.

N.B.—Since writing the above I have observed, in some
gatherings from the neighbourhood of Duddingston Loch and
Arthur’s Seat, as well as in some from the Bridge of Allan,
the latter made by Dr. Greville, and in one from Borthwick,
made by Dr. Balfour, a form apparently allied to P. globiceps,
which for the present I shall call P. globiceps 6. It has a
much less elegant curve, but in most points agrees with the
form here described.

35. Stauroneis obliqua, W.G.—This very curious and well-
marked species has only occurred, as yet, in the gathering
from Lochleven, in which it is, though far from frequent,
always to be found, from 3 or 4 to 10 or 12 in a slide. In
form it is elliptico-lanceolate, usually rather short and broad,
sometimes longer. The stauros is broad and distinct, but less
so towards the margin, which, however, it reaches. The
strie are fine and slightly curved from the middle towards
the extremities ; but the most striking character is the peculiar
position of the median line, which does not, as usual, unite
the apices centrically, but has one of its ends on one side of

OF BRITISH FRESH-WATER DIATOMACEZ:. 11

the apex, the other on the opposite side of the opposite apex,
thus dividing the valve into two halves, which, although equal,
are so placed that the narrowest part of one corresponds to
the broadest of the other, as is well shown in the figures. In
some cases, as may be seen in the larger figure, the median
line is slightly sigmoid, but this is rare. The obliquity just
described, which I do not remember to have seen in any other
species, is invariably present; at least I have found it in at
least 150 specimens which I have examined. The length is
from ‘001 to 0022 inch, Stria, by the measurement of Pro-
fessor Kelland, 45 in ‘001 inch. I may add that Professor
Kelland thinks the median line is twisted, as it were on its
own axis, to a certain extent.

36. Stauroneis (2) ovalis, W. G.—This very pretty little
form first occurred to me in some gatherings made on the
River Findhorn by my friend Mr. Crawford, of Overton. In
one of these it is quite the predominating form, and in all of
them JV. incurva, already described, also occurs. I have
recently found it, much more sparingly, in Lochleven, in
which I also detected N. incurva. ‘The form is a pure oval,
‘001 inch long, and it is crossed by what at first I took for a
stauros, which is broad and reaches the margin. But I can-
not, with a high power, satisfy myself that this is really a
stauros, as it seems to vanish, or is so transparent that it
cannot well be traced. The valve appears to be convex, as
when the stauros is brought into focus, the other parts are
but dimly visible. The strie have not yet been resolved.
As the genus of this form is not yet determined, I retain the
name Stauroneis with a mark of interrogation, It is more
probable that it may prove to be a Cocconeis. At all events,
it appears to be a distinct and well-marked species. Length
about ‘O01 inch. I have recently observed it in two gather-
ings from Lanarkshire.

37. Stauroneis dubia, W. G.—This is a still smaller form,
and, as the name indicates,“its true position is not quite
settled. It occurs in some of the gatherings from Dudding-
ston Loch, and in others from the Hunter’s Bog, and is far
from scarce. It is small, narrow, of an elliptico-lanceolate
form, the apices slightly truncated. There is a stauros,
whether true or false is not yet ascertained, but probably
true. When examined under a high power, the valve exhibits
two parallel marginal lines within the margin on each side,
the stauros not reaching farther than the inner one of these
lines. The striae have not yet been resolved. Length from
0008 to ‘0012 inch.

38. Surtrella tenera? W. G.—This pretty form occurs in

12 DR. GREGORY, ON SOME NEW SPECIES

the Elchies gathering, where it is frequent, along with S.
biseriuta and §S. pills; so that it can be at once distinguished
from them. It has exactly the form of S. nobilis, but is
smaller and rather narrower in proportion. It differs from
S. biseriata in having one end round, the other acute. From
both of these species it differs still more in the fact of having
its canaliculi very much narrower and more numerous. Its
length is from ‘003 to ‘005 inch. Canaliculi fine, about 10 in
‘O01 inch. It is possible that it may be the perfectly deve-
loped S. linearis, but I have not as yet been able to ascertain
this.

39. Gomphonema insigne, W. G., rude, Sm.—This species
was first observed in some gatherings froin Duda Loch,
but I found it subsequently to be pretty widely distributed. It
is distinguished by its size and the coarseness of its striation.
The 8.V. is doubly conical, the angle at the broadest part being
strongly marked. The F. V, is cuneate. Length from ‘002
to 0024 inch. Strie 18 to 20 in :001". I believe that
Mr. Smith has ae this form, which I sent him when I
first observed it, G. rude, but I am not quite certain of this.
If so, there can be no objection to his name.

40. Gomphonema ventricosum, W. G.—This well-marked
species occurs in a gathering from the banks of the Spey,
near Elchies, different from that which I have spoken of as
the Elchies gathering. The middle part is much expanded,
and both extremities are obtuse and rounded, the longer limb
being a little expanded at the apex. It is short and broad in
proportion, and very uniform in its characters. Length about
0014 inch. Striz about 30 or 32 in 001". Dr. Greville has
recently (April, 1855) found this species tolerably frequent in
several gatherings made by him near the Bridge of Allan.

41. Gomphonema equale, W. G.—This species occurs in
the Elchies gathering, which is from a spring in the grounds
of the house. [ have seen it also in that from Elgin, and in
some of the other Banffshire gatherings, as well as in some
from Lanarkshire. It is shorter than the last, and is distin-
guished from it, as well as from other Gomphonemata, by the
position of the nodule, which is central, whereas in other
species it lies always nearer one end. In form it is linear
elliptical, but towards the extremities it is suddenly con-
tracted, and again expands, so as to be almost capitate. In
this it agrees nearly with some forms of G. tenedlum, from
which, however, it differs, both in having much wider and
coarser stria, and in the central position of the nodule.
Length ‘O01 inch. Striz rather distant, not reaching the
median line, conspicuous, about 22 or 24 in “001”.

OF BRITISH FRESH-WATER DIATOMACEZ. 13

42. Gomphonema Sarcophagus, W.G.—This species occurs
abundantly in the Lochleven gatherings, but it occurs also
in several gatherings made near Edinburgh, and in others
from Fife, Stirlingshire, Lanarkshire, and elsewhere. Indeed
it would seem not to be uncommon. In form it is linear,
rather narrow, the sides gently curved, so as to form a sort of
shoulder at the widest part, after which it contracts a little,
and again expands to a somewhat truncate extremity. The
opposite end is narrower, and, with the exception of a trifling
expansion at the apex, ae continuously narrower. These
things give to it very nearly the shape of a coffin. The F. V.
is, as usual in this genus, cuneate. Length about :0014 inch.
Stria 20 to 22 in -001".

I have now only to add a few words on the distribution of
the Diatomacee in our fresh waters. I have not only found,
~as Ehrenberg has done, that a large number of species occur
in every locality, but even in the case of the forms just
described, which, from their having been overlooked, might
be supposed to be very rare, most of them have been observed
in more than one, frequently in several different and distant
stations.

It must not be supposed that the gatherings which I have
examined are exhausted. The fact is, that only a small
number of them, no doubt the most interesting and the most
promising, have been at all minutely explored, and I would
particularly direct attention to the fact, that with the exception
of only two or three spec ies, all the forms now figured are
actually to be found in four gatherings, those, namely, of
which I have spoken as Elchies, Elgin, Lochleven, and Dud-
dingston Loch. Several of diese: Enema wet first observed in
other gatherings, though not many, but in time they have all
been found in these four. Nay, the Lochleven gathering
alone has been found to yield nearly the whole of them. If,
therefore, | had been confined to these four gatherings alund:
I should have detected, by careful exploration, all the forms
now figured as new. This shows what I formerly alluded to,
the importance of minute examination, without which many
iuteresting forms are daily overlooked. It is no argument
against this to say that species cannot well be ascertained
from a few scattered specimens, for what is rare and scattered
to-day, may be found in abundance to-morrow. ‘Thus the
doubtful Stuwroneis which I have figured occurs very sparingly
in the Lochleven gathering. Had it never occurred but there,
its character eould-haye-been easily ascertained. But in the
Findhorn gatherings it occurs abundantly. Stauroneis obliqua
occurs, at present, only in Lochleven, and that sparingly ; but

14 BUSK, ON THE STRUCTURE AND

its characters are so well marked that we need not wait till it
shall be found in abundance, as it probably will some day.
It would, however, certainly have been overlooked in Loch-
leven, but for the minute search to which the gathering was
subjected. The same remarks apply to Navicula lacustris and
to Navicula lepida.

Whenever, therefore, a gathering is met with which appears
to contain a great variety of forms, like the four above men-
tioned, it should be systematically and minutely searched,
and any striking forms, no matter how scarce, noted and
figured. If true species, they will most probably be found in
greater abundance elsewhere.

It is much to be regretted that no work yet published con-
tains figures of all the known species or forms named as
species by their observers. Even in Ehrenberg’s last great
work, in which many hundred species are figured, I obserye
the names of about 350 species, most of which are described
as remarkable or characteristic of certain localities, not one of
which is figured, although most of the common species are
many times represented.

Supposing, then, that all those forms which I have just
described as new to science should prove to be good and
distinct species, of which I cannot, of course, be sure, it is out
of my power to ascertain whether they may not agree with
some of the species named, but not figured, in his last work,
by Ehrenberg. I ought to mention, however, that several of
the species of my first section, new to Britain only, were con-
sidered by myself and others as new to science, till 1 found
them figured in Ehrenberg’s ‘ Microgeologie,’ when of course
I adopted his names for them.

An Account of the SrructurE and Rexations of Sacirra
BrpuNcTATA. By G. Busx, F.R.S.

THE minute creature to which the above name has been
given, though abundant, perhaps, in all seas, and noticed so
long ago as in the year 1781, has received but little attention
from zoologists in general. Its curious and interesting struc-
ture, however, and doubtful position in the animal kingdom,
render it a subject well worthy of further research ; and its
minute size, and the extreme delicacy and transparence of its
tissues, make it peculiarly an object of microscopical inves-
tigation. Though perhaps unknown, even by sight, to many
of our readers, the Sagitta bipunctata will probably be met
with on every part of the coast; and it may be procured,

RELATIONS OF SAGITTA BIPUNCTATA. 15

without difficulty, at any rate in fine and calm weather, by
means of a small muslin towing net over the side of a boat.

The animal, which has the form of a pointed needle, is
from one to two inches in length or less, and transparent as
the clearest glass. In warm, calm weather it swims on the
surface of the sea, and occasionally in the most surprising
numbers, In these latitudes it appears to be in a state of the
most complete maturity in August and September.

The present account pretends to little originality, except
in the figures, some of which were made by myself in 1852,
from specimens taken in Sandown Bay in the Isle of Wight;
and. for others, | am indebted tof{Mr. Huxley, whose observ-
ations upon this creature were made in the course of the
voyage of the ‘ Rattlesnake’ in the seas of Australia. That
accurate observer, who has also studied the British form, is of
opinion that the Sagitta he examined in the southern hemi-
sphere and elsewhere, is identical with that found on our
coasts ; and I have, therefore, no hesitation in availing my-
self of his figures, illustrating the nervous system.

The earliest notice of the animal which forms the subject
of this paper was given by Martin Slabber* in 1781, by whom
also the very appropriate name of Sagitta was applied to it.
This notice, however, seems to have been forgotten until
M.M. Quoy and Gaimard, when commencing their second
voyage round the world, ae dicequened the animal, as it may
be said, in the Straits we Gibraltar. The species whscined by
them was named Sagitta bipunctata, and is probably identical
with that now under consideration. This form and other
species of the same genus have been since noticed and more
or less accurately described and figured by several authors,
amongst whom may be noticed Scoresby, D’Orbigny,}
Forbes,§ Darwin,|| Krohn,{] Wilms,** Huxley{f and Busch.t{

* Physikalische Belustigungen, oder mikroskopische Wahrnehmungen
von 48 in-und auslindischen Wasser-und Landthierchen.’ Nurnberg, 1781.

+ ‘ Account of the Arctic Regions,’ vol. ii., Plate XVI.

{t ‘ Voyage dans l’Amerique meridionale ; Mollusques, p. 140, Plate X.,
figs. 1—7.

§ ‘ Annals Nat. Hist.,’ 1843.

|| ‘ Annals Nat. Hist.,’ Ist Ser., vol. xiii., p. 1.

{1 ‘ Anatomisch-physiologische Beobachtungen tib. die Sagitta bipunc-
tata,’ 1844, ‘N achtragliche Bemerkungen “ib. den Bau der G attung
Sagitta, nebst der Beschreibung einiger neuen Arten.’ (Wiegmann’s
‘ Archiv.,’ 1853, p. 266, Plate XII.) And Miiller’s ‘ Archiv.,’ 1853, p. 140.

** « Observationes de Sagitta, mare Germanicum circa insulam Helgo-
land incolente,’ 1846.

++ Report of British Association, 1851. (Trans. of Sections, p. 77.)

tf Beobachtungen tb. d. Anatom. u. Entwicklung einiger wirbellos.
Seethiere, 1851, p. 93.

16 BUSK, ON THE STRUCTURE AND

The present account of the animal, however, has been com-
piled chiefly trom the observations of Krohn and Wilms,
whose papers on the subject appear to include nearly all of
importance that has as yet been made out respecting the
anatomy and physiology of Sagitta.

The body of the Sagztta lipunctata is as transparent and
clear as glass, cylindrical or slightly flattened, pretty regu-
larly fusiform, though rather more attenuated posteriorly than
in front (PI. II. fig. 1), when it again expands at the extremity.
It is divided into three distinct portions, the “head, “ trunk,”
and “ caudal portion,” which are separated from each other
by transverse septa. Each of these portions will be sepa-
rately described. Posteriorly the body is furnished, on the
sides and extremity, with five delicate membranous expansions,
which have received the name of “ fins,” though bearing no
real analogy with the fins of a fish. ‘These “ fins” are all
in the same plane, and spring from a line equidistant between
the dorsal and ventral surfaces. ‘The anterior pair of lateral
fins, which are far smaller than the posterior, are situated
nearly in the middle of the body, being equal in length to
about 1-5th of the extreme length of the animal. The
posterior pair of lateral fins, which are both longer and wider,
extend from the posterior border of the former to within a
short distance of the caudal extremity, where they terminate
rather abruptly. Anteriorly the two pairs of fins are often
apparently continuous with each other by a very narrow band
of similar texture; so that, in fact, in many cases the lateral
fins might be described as constituting only one pair, of varying
width in different parts. ‘The caudal fin is, however, quite
distinct. It is broad and somewhat rounded, expanding like
a fan from the posterior extremity of the body, and passing a
short distance up on each side. These “ fins” are composed
of an excessively delicate and apparently structureless mem-
brane, which is strengthened by very slender radiating fibres,
placed very closely together, and appearing to be somewhat
thicker at the base than more outwardly. Although very
slight injury tears the fin in the direction of these apparent
fibres—and its edge, thence, often appears to be fimbriated—
the fibres themselves cannot be readily isolated, and there is
every reason'to believe that the edge of the fin in the perfect
state 1s entire.

The integument, except on the head, is comparatively
speaking thick and dense. It is covered with a very delicate
epidermis, composed of rounded or polygonal cells. The
existence of this epidermis was denied by Krohn in his first

RELATIONS OF SAGITTA BIPUNCTATA. 17

memoir, but is admitted by him in his subsequent observa-
tions. When the animal is placed in spirits of wine, the
surface presents numerous distinct, whitish, well-defined spots,
which closer examination shows to be rounded eminences
belonging to the cellular epidermis, and from which project
minute bundles of excessively delicate, rigid filaments or
sete. These spicules, as they may be termed, were first
pointed out by Wilms,* and the species on that account was
termed by J. Miiller, S. setosa; but from Wilms’ description
it appears to differ in no important particular from S. bipunc-
tata. Wilms describes them as constituting a single series
on each side, whilst Busch,f in speaking of a form termed by
him S. cephaloptera, notices that they are disposed, in that
species, in a double series on each side. Krohn also remarks
that he has seen these spicular bundles, not only in S. bipunc-
tata, but in several other species also; their existence, there-
fore, would seem to be general throughout the genus, and
careful observation may, perhaps, educe from their disposition
specific characters of some importance. In S. bipunctata, the
spicules project on all parts of the body, but they appear to
be more numerous on the anterior portion than elsewhere.
So far as I have observed, they seem to be scattered irregularly
over the surface, although Krohn states that they are appa-
rently arranged in symmetrical longitudinal tracts on the two
sides. He says also, that they occur on the caudal fin where
they are disposed in a curved line across its width. In some
species he remarks that they exist also on the posterior
lateral fins.

As has been said before, all these bundles of spicules are
placed upon rounded eminences, and in most cases they
appear to radiate on all sides from the centre of the eminence ;
but closer examination will sometimes show that they are
disposed in a simple line, and in close contiguity. This is the
case, at any rate, according to Krohn, in S. bipunctata.

Notwithstanding their rigidity, the filaments, of which
these spicular bundles are constituted, have nothing in
common either with spines (aculei) with which Wilms com-
pares them, nor with sete, as they are termed by Busch.
According to Krohn they are epidermic processes. And this
notion he remarks is supported by the circumstance that the
spicules, like the epidermis itself, are detached With extreme
readiness, and consequently are only to be observed in per-
fectly fresh specimens in a good state of preservation.

Some analogy may, perhaps, be conceived to exist between
the filaments of which these epidermic spicules are consti-
2b. c,4 p.11, fig..1, 16: + Lc, p. 93.

VOL. IV. Cc

18 BUSK, ON THE STRUCTURE AND

tuted and those by which the “ fins” are strengthened. With
reference to the latter, Krohn remarks that after repeated
observation he is convinced that these fibres are closely allied
to the sete of Annelids, Like these they are flexible to a
certain extent, and are readily broken into pieces. In form
they exactly resemble the simple or capillary sete. He
remarks also, though this hardly accords with my own ob-
servation, that they are merely loosely imbedded in the
homogeneous substance of the fin; since they may often, in
otherwise uninjured “ fins,” be seen bare for a considerable
extent. At any rate their connection with the substance of
the fins is by no means so close as he was formerly inclined
to believe.*

Immediately beneath the integument is placed a layer of
longitudinal muscles extending uninterruptedly from the head
to the caudal portion of the body. These muscles are dis-
posed in two broad bands, one situated on the dorsal and the
other on the abdominal aspect, and separated on each side by
a clear space, which is brought more distinctly into view, as
Krohn remarks, when the muscles themselves are rendered
opaque by immersion in spirit. Each band is again sub-
divided, but less distinctly, into a right and left portion; so
that in fact the muscular apparatus might be described as
consisting of four bands, a dorsal and an abdominal on either
side. ‘These muscular bands are composed of long trans-
versely striated fasciculi resembling those of insects.

The disposition of the muscular apparatus would indicate,
as observation shows to be the case, that the movements of the
animal are chiefly those of flexion and extension in the trans-
verse plane of the body, and consequently that the Sagitta, as
was observed by Quoy and Gaimard, swims like a Cetacean
by the horizontal blows of its caudal fin upon the water.

The Nervous system, in Sagitta bipunctata, may be described
as consisting of two principal ganglions, one situated on the
dorsal aspect of the head, the cephalic ganglion, and the other
on the ventral aspect of the trunk, the ventral ganglion. ‘The
one consequently is above the cesophagus, and the other below
it,—supra and sub-cesophageal ganglia. These ganglia—which,
as well as the nervous trunks, lie immediately beneath, and in
close contact with the integument—are mainly composed, as in
other instances, of ganglionic cells, but in the ventral ganglion
there appears to be a certain amount of white nervous matter
in the centre (fig. 8, /).

The cephalic, or supra-cesophageal ganglion (fig. 7), is
situated in the mesian line, a short distance from the anterior

* Loa; pik

RELATIONS OF SAGITTA BIPUNCTATA. 19

extremity of the head. It is of a more or less quadrangular
form and flattened, in large specimens measuring about + mm,
in length. Three pairs of nervous cords proceed from it.

1. An anterior (fig. 7, bb) which curves outwards, and then
backwards towards the process of the head upon which the
buccal hooks are placed, to terminate according to Krohn,
in the muscles by which the hooks are moved, close to which,
he says, that each nerve presents a minute ganglionic enlarge-
ment from which several filaments are-given off to be distri-
buted to the muscles.

The posterior pair of nerves arising from the cephalic gang-
lion (fig. 7, ¢ c) pass backwards, in a divergent direction, and
terminate in a rounded ganglionic mass, in the centre of which
the eye (fig. 7, hk) is, as it were, imbedded. These optic
ganglia, according to Krohn, are composed of distinct ganglionic
cells; but it would appear from Mr. Huxley’s observations,
that the optic nerves, as they may be termed, also exhibit a
smaller ganglionic enlargement immediately before entering
the optic ganglion (fig. 7,7). The optic ganglion and the eye
lie in a special closed cavity in the integument of the head.

3. The third pair of nerves arising from the cephalic gang-
lion (fig. 7, dd) are given off from the sides of that body,
curving backwards and downwards, so as to pass on either side
of, and to get beneath the oesophagus, where they approach
each other again, and becoming nearly parallel in the mesian
line of the trunk, join the ventral ganglion. They constitute,
therefore, what may be termed an cesophageal commissure,

The ventral ganglion (fig. 8) lies in the middle of the ventral
surface of the trunk, also immediately beneath the integument,
which is seen to be somewhat elevated by it when the animal
is viewed on the side. It is situated between the head and
the lateral fins, though rather nearer to the latter. It is of an
elongated, oval form, and in full-grown individuals about 1}
mm. long. There may be distinguished in it a lighter-coloured
nuclear or medullary substance (fig. 8, 4), which occupies a
central tract, and a darker-coloured, coarsely granular cortical
layer, composed apparently for the most part of ganglion-
globules. Four principal nervous trunks proceed from this
ganglion: an anterior pair (fig. 8, d d), which are continuous
with the lateral trunks given off ‘from the cephalic ganglion
(fig. 7, dd), and constitute the cesophageal commissure ; and
a posterior, (fig. 8, ff), which run directly backwards, slightly
diverging from each other. These trunks are, upon the whole,
stronger ant rather shorter than the anterior pair, inasmuch as,
according to Krohn, they do not extend much beyond the an-

terior pair of lateral fins. He states that each trunk terminates
c 2

20 BUSK, ON THE STRUCTURE AND

in a sort of cauda equina, composed of numerous minute
nervous twigs. From the sides of the ventral ganglion, and
according to Krohn, from the nervous trunks also, are given
off numerous nerves in rapid succession, which, according to
the same observer, curve upwards towards the dorsal surface
of the trunk, subdividing into numerous twigs, which anasto-
mose, and thus constitute a very intricate plexus beneath the
integument. The latter part of this statement may perhaps
be erroneous, but at any rate there is no doubt of the fact, that
numerous small lateral branches are given off, apparently sym-
metrically, from the sides of the ganglion itself, as shown in
fig. 8.

” The Head.—This portion of the animal is distinctly sepa-
rated from the trunk, and is surrounded by a sort of mem-
branous hood, which is capable of being drawn backwards
over it. The upper surface of this hood is level with that of
the trunk, whilst the lower forms a plane inclined from above,
and anteriorly downwards and backwards. When fully ex-
panded, the hood, except inferiorly where it presents, in the
middle line, a longitudinal opening for the mouth, appears to
envelop the entire head ; when retracted, the head is exposed,
particularly on the sides, when the following parts are dis-
played. 1. On each side a series of curved pointed hooks,
(fig. 3, c), which, when the hood is expanded, close from either
side of the mouth. The number of these hooks does not
appear to be very constant, and the anterior hooks are usually
shorter than the others. 2. Besides these larger buccal hooks
there will be observed, at the anterior extremity of the head,
two curved series of smaller denticles (fig. 3, a), one behind
the other on either side.

On each side the inferior surface of the head presents a
large, rounded eminence, apparently composed of the muscles
by which the buccal hooks are more directly moved, and be-
tween these buccal lobes is situated the oval opening in the
form of a longitudinal slit or fissure, which is crossed poste-
riorly by a kind of fimbriated border, stretching across from
one buccal lobe to the other (fig. 3, 0).

The pharynx or esophagus commencing at this point is a
short tube with thick muscular walls, a little larger in
diameter than the intestine, and extending but a short distance
beyond the junction of the head and trunk. It is bounded on
either side by the buccal masses above noticed. On the upper
surface of the head, on either side, and pretty close to the
median line, will be seen the “ eyes,” (fig. 7,2). These organs
are composed apparently of a mass of black pigment, around
the margin of which will be noticed clear points, or cornea,

RELATIONS OF SAGITTA BIPUNCTATA. 21

which, according to Mr. Huxley, are disposed in three distinct
sets. As has been before stated, the eyes are lodged in the
upper surface of the optic ganglia, and contained together
with them in special cavities excavated in the integuments of
the head.

2. Trunk.—This portion, which constitutes the principal
part of the animal, is an elongated hollow sac containing the
muscular hands above described, the intestinal canal and ter-
mination of the cesophagus, together with the ventral ganglion
and its branches, and the ovaries which are situated poste-
riorly.

The intestinal canal, which commences at the termination of
the cesophagus, is a simple, straight, somewhat compressed
tube, extending from this point to the junction of the trunk
with the caudal portion, where it makes a rather abrupt
curve downwards, becomes contracted, and terminates in the
anus, which presents the form sometimes of a rounded aper-
ture, sometimes more that of an elongated slit, but in either
case projecting beyond the surface. The walls of this simple
tube are composed principally of a layer of annular fibres,
strengthened on the upper and under sides by a narrow band
of longitudinal fibres, which, according to Krohn, are situated
external to the annular. The tube is lined internally by an
epithelium, composed of elongated prismatic cells, furnished,
perhaps throughout, with long vibratile cilia. [tis supported
in its place above by a continuous median band, and _ below it
is held by numerous slender, usually branched threads, disposed
in a line corresponding to the band above. The perigastric
cavity is thus imperfectly divided, as it were, into two lateral
compartments.

The intestinal canal is generally empty, but ina few instances
Krohn has seen in it fragments of minute fish and crustacea,
and in some cases portions of other Sagitte.

The “ caudal portion,” and the ovaries, constitute the sexual
apparatus, which will now be described.

1. The female portion of this apparatus consists of two
organs, which are situated in the posterior part of the cavity
of the trunk, on either side of the terminal portion of the in-
testine (fig. 4, a, a, fig. 6). These organs, which may be
termed ovaries, in the mature state, are often of considerable
size, extending even beyond the upper pair of lateral fins.
They are elongated sacs, which are attached by a longitudinal
band to the lower wall of the trunk. Inferiorly the ovary
curves abruptly upwards and outwards, forming a sort of short
oviduct, which opens externally between the upper muscular
band and the base of the posterior pair of lateral fins. In the

22 BUSK, ON THE STRUCTURE AND

outer portion of each ovary is a dense granular tract (fig. 6, @),
the remainder of the cavity being occupied by a more finely
granular stroma in which the ova are developed, attached at
first by short pedicles to the placental tract. In the outer
portion of this tract runs a slender cecal canal, which may be
traced close to the opening of the oviduct (fig. 6, 6). This
canal, which was first noticed by Wilms (1. c. p. 13, fig. 10), is
regarded by Krohn (Wiegm. Archiv. 1853, p. 269), as a
receptaculum seminis, seeing that it is occasionally found to be
filled with actively-moving spermatozoa. According to Wilms
and Huxley, the canal is lined with cilia, but Krohn is of
opinion that this appearance of cilia is due to the presence of
the motile spermatozoids. The ova (fig. 6, ¢) present no
peculiarity, except that Wilms and Krohn concur in stating
that a germinal spot is never observed in the comparatively
large germinal vesicle.

2. The male apparatus.—The caudal portion of the animal
(fig. 1, d) is divided by a vertical, longitudinal septum, into
two perfectly distinct compartments. These compartments
may properly be termed the festes, as it is them that the deve-,
lopment of the spermatozoa appears to take place, which is
thus described by Wilms(l.c. p. 13). In younger individuals,
each compartment contains a greater or less number of vesicles
of various dimensions, some spherical, others of irregular form,
elongated, and ovoid. At first sight they seem to be filled
with a sort of granular substance, but when a little larger, are
plainly seen to contain minute spherical cells. In animals
nearer maturity, besides these cysts, there will also be noticed
cells in which, upon the addition of acetic acid, a nucleus is
plainly visible. From these aggregations of cells (fig. 9),
which are always somewhat less in size than the cysts above
noticed, the spermatozoa are developed. At a certain period,
slender filaments are seen to proceed from them, causing the
appearance as if the cells were beset with spines, whilst others
present the appearances represented in fig. 12, a, 6, indicating
a further stage of development. The central cellular mass
(shown at a, fig. 12) gradually diminishes in bulk as the
filamentary portions become more and more developed (fig. 12
6), and gradually disappears altogether, nothing remaining but
bundles of spermatozoids attached to each by their heads.
These bundles eventually break up into separate spermatozoids.
The mature spermatozoid is a long filament, slightly enlarged
at one extremity, beyond which, however, the point is usually
prolonged in the form of a very delicate short thread (fig. 11).

A remarkable circumstance observable in the spermatic
cavities of Sagttta, is the continual cyclosis performed by their

RELATIONS OF SAGITTA BIPUNCTATA, 23

contents.* These will be seen constantly ascending on the
outer, and descending on the internal wall or septum in the
directions indicated by the arrows in fig. 4. The cause of this
motion is stated by Krohn to depend upon the presence of
scattered cilia in the posterior part of the cavity.

The spermatozoids thus formed make their exit from the
cavity in a very curious mode. On each side of the caudal
portion will be observed a projection, (figs. 1 and 4, e e,) which
may, perhaps, be regarded as a sort of ejaculatory apparatus.
These processes are hollow sacculi, which open externally by a
rounded orifice situated at the upper end, and communicate
with the interior of the compartment to which they belong,
through a canal excavated in the integuments of the caudal
portion. If, as Krohn observes, one of the seminal compart-
ments be laid open by a longitudinal incision on the under
surface, and the contents carefully removed, an opening sur-
rounded by a raised margin will be clearly seen at a short dis-
tance from each ejaculatory sac. This orifice leads into the
canal above mentioned, which runs along the corresponding
border of the upper muscular band, making a slight curve
posteriorly, gradually contracting in size, and finally opening in
the cavity of the ejaculatory sac. The inner wall of these
efferent canals, as well as of the external sac, is lined with an
actively vibrating ciliated membrane.

With respect to the mode in which the spermatozoids come in
contact with the ova nothing is known, though it would seem,
if Krohn’s observation above related, of the presence of sper-
matozo ain the cecal canal contained in the ovary be confirmed,
that they must make their entrance in some way into that
organ, It is more probable, however, that the ova are impreg-
nated after extrusion; and that this is the case, is rendered
the more likely by the circumstance that innumerable sperma-
tozoids in the most active motion may occasionally be observed,
swarming out of the orifice of what I have termed the ejacula-
tory sac (fig. 5). And it seems scarcely possible that these
motile filaments should make their way spontaneously into the
narrow-and close opening of the oviduct, which they must do
in order to reach the canal in question.

The Sagitta is obviously oviparous; but with respect to the
further development of the ova after deposition, little is known.
According to Krohn (Wiegm,. Arch. 1853, p. 270), the vitellus
consists of numerous cells containing an albuminous fluid, and
in which he was unable to perceive any vitelline granules.
It is surrounded by two membranes. The internal, which

* Krohn remarks (p. 13), that a similar movement of the spermatic
globules is observed in the testicular vesicles of the Leech.

24 BUSK, ON THE STRUCTURE AND

closely envelopes the vitellus, is thin and firm; the proper
vitelline membrane, whilst the outer is much thicker, and
according to him of a gelatinous consistence, swelling up
rapidly when the ova escape into the surrounding water. At
a later period it is sometimes absent, although the development

is not, according to Krohn, by this interfered with. Mr.
Darwin also (1. c.) assigns an outer envelope to the ovum, but
it would seem that this envelope was of a firmer consistence
than the one described by Krohn, since he states that it is rup-
tured soon after the commencement of partial segmentation of
the vitellus, which undergoes its further development after it
has thus escaped.*

Many species of Sagitta are described by different authors,
but it would seem that considerable confusion still exists on
this subject. One thing appears tolerably certain, viz., that
the species common on the British coast, and which is the one
here described, is, as before stated, very widely distributed in
all seas from the north to south antarctic oceans. And it may
well be supposed that superficial observation of specimens at
different ages and of different sizes, may have caused an unne-
cessary multiplication of species.

Krobn, who considers that the number, position, and form

* In Siebold and Kolliker’s ‘ Zeitschrift f. Wissens. Zoologie, Bd. v.,
p. 15, is a short notice respecting the development of Sagitta, by C.
Gegenbaur. He states, that the process of segmentation terminates in
the production of an embryo of a rounded form, in which two kinds of
cell-masses may be recognized,—one central, constituted uf minute, and a
well-defined peripheral layer, composed of larger cells. A depression is
now formed at one point of the surface, which gradually advances to the
centre, constituting the rudiment of the intestine. The embryo now
appears to increase in length, in consequence of which, since it completely
fills the cavity of the ovwm, it becomes bent, and is ultimately coiled in a
vermiform fashion. ‘I'he cavity of the trunk may be distinguished,
traversed by the intestine, which forms, as it were, a vertical septum ;
but, besides this, no other internal organs are apparent. At this period
the embryo often moves, and on the addition of acetic acid the muscular
bands in the trunk are visible, completely formed, and exhibiting the fine
transverse stric. The fins arise as simple lateral outgrowths of the body.
In this condition the animal leaves the ovwm, about ?'" in length, and
already presenting in all respects the character of the full-grown Sagitta.
The other organs, consequently, are not developed until after the animal
has quitted the ovwm. In the entire course of development, many stages
of which, particularly those which succeed complete segmentation, are
very difficult to be understood, ci//a never make their appearance.

If the anatomy of this creature had not satisfactorily shown that it
belongs neither to the Pteropoda, nor to the Heteropoda—this would have
been rendered certain by its mode of development, whieh does not accord
in any respect with the Molluscan type. What the real position of Sagitta
is I will not determine.

RELATIONS OF SAGITTA BIPUNCTATA. 25

of the lateral fins will afford most useful diagnostic characters,
describes the following species :—

1. S. multidentata (Wieg, Arch. 1853, p. 271, Plate 12, fig.
2).—Which in habit closely approaches the S. setosa of Wilms
(our S. bipunctata). 'The posterior fins are longer and wider
than the anterior, which extend in front to about the anterior
third of the body. The number of hooks is from 9 to 11. That
of the denticles in front of the mouth (fig 3, a), is in the ante-
rior row from 5 to 8, and in the posterior from 12 to 13.

He notices another form closely resembling the above,
but characterized by the existence of a horny, toothed ring
around the orifice of the ejaculatory sacs.

2. S. serrato-dentata (I. c. figs. 8 and 4).—Which appears to
resemble the foregoing in nearly all respects, except in the
conformation of the hooks, which are described as serrated on
the inner edge for about half their length. The number of
hooks is from 6 to 8 on either side. The denticles in the an-
terior row are never more than eight in number on each side,
whilst in the posterior there are as many as 18. The bundles
of rigid sete are disposed symmetrically in eight lateral rows,
four dorsal and four on the ventral aspect. It is a very small
species, not exceeding 44 m. in length.

3. S. lyra (1, ¢., fig. 5).—The caudal portion of the body
very short and separated by a groove from the elongated
trunk. The two pairs of lateral fins are apparently continuous
with each other, and the anterior are much longer than the
posterior, and extend far anteriorly. The number of hooks
is 6 to 8 on either side; of the denticles, 7 in the anterior
and 11 in the posterior series. The bundles of set@ are irre-
gularly distributed over the surface of the body. It is a large
species, attaining the considerable length of from 3 to 32
centim.

4. S. draco (l. c., fig. 6)—The body of this rare form is
short and thick, and invested for the anterior three-fourths of
its length, by a very considerable layer of large, thick-walled
cells. The caudal portion is very long, the trunk short, and
the caudal fin of large size. The anterior pair of lateral fins
is wholly wanting, and the pair corresponding to the pos-
terior fins of other species do not extend beyond the caudal
portion of the body. The species is remarkable also for the
existence of two lateral and opposite bundles of numerous,
very long, freely-floating filaments, seated upon special emi-
nences, which again are placed upon the cellular layer sur-
rounding the anterior part of the body. The filaments are of
soft consistence, ligulate, and constituted of parallel longitu-
dinal fibrilla. There are ten hooks on either side; eight

26 BUSK, ON SAGITTA BIPUNCTATA.

anterior denticles on each side and 18 posterior. The
bundles of rigid sete are scattered irregularly over the surface,
The only individual met with by Krohn was one centimetre
in length.

Other species described by authors are—

5. S. cephaloptera (Busch, |. c., pl. xv., fig. 2).—Distin-
guished by a radiated disc on the anterior part of the trunk,
and two tentacular processes on the sides of the head.

6. S. rostrata (Busch, 1. ¢., fig. 7)—Distinguished from
S. setosa, Wilms, by the presence of a large rounded eminence
on the anterior part of the head, whick Krohn imagines may
be caused in a young specimen of a Sagitta by the cephalic
ganglion.

7. S. bipunctata, Quoy and Gaimard, which we regard as
identical with—

8. S. setosa, Wilms, the species here described, and pro-
bably the parent of other species, among which perhaps may
be enumerated those named by D’Orbigny (Voyage dans
’Amerique Meridionale, tom y., p. 14, Pl. 10) according to
the number of their fins, as S. diptera, S. triptera, and S. hex-
aptera. If all these really belong to Sagitta at all, which,
in the absence of farther information than that given by
D’Orbigny, may be regarded as doubtful, S. hexaptera, at
any rate, may be considered identical with S. bipunctata.

With respect to the systematic position of Sagitta, very
considerable difficulties arise in the determination of it. Mr.
Huxley (I. c., p. 77) remarks that ‘ Sagitta has been placed
by some among the Mollusca, a view based upou certain
apparent resemblances with the Heteropoda. These, however,
are superficial ; the buccal armature of Sagitta, for instance,
is a widely-different structure from the tongue of Firola to
which, when extended, it may have a distant resemblance.”
“There appears,” he says, “ much more reason for placing
this creature, as Krohn, Grube, and others have done, upon
the annulose side of the animal kingdom; but it is very
difficult to say in what division of that sub-kingdom it may
most naturally be arranged.” After surveying the points of
resemblance and difference between Sagitta and the nematoid
worms and certain Naiadze, Mr. Huxley concludes by obsery-
ing “ that the study of its development can alone decide to
which division of the annulose sub-kingdom Sagitta belongs ;
but that until such study shall have demonstrated the contrary,
he stated his belief that Sagitta bears the same relation to the
Tardigrada and Acaride that Linguatula (as has been shown
by Van Beneden) bears to the genus Anchorella, and that the

MAGNIFYING POWER OF SHORT SPACES, 27

young Sagitta will, therefore, very possibly be found to re-
semble one of the Tardigrada, the rudimentary feet with their
hooks being subsequently thrown up to the region of the head
as they are in Linguatula.”

Krobn, with much hesitation, is inclined to regard it as
belonging to the Annelid group, with which it would certainly
at present appear to exhibit a very probable relationship.

On the Maaniryina Power of Snort Spaces zllustrated by

the TRANSMISSION of Liaut through Minute APERTURES.
By Joun Goruam, M.R.C.S.E., &e.

Havine described in the former papers the appearances
observable when pencils of light from small ezreular apertures
are partially intercepted by certain opaque or transparent
objects of definite shape and size; and having shown that
whether shadows or illuminated spaces are thus used, they
serve to exemplify the magnifying power of short intervals
existing between the organ of vision and the object to be ex-
amined, inasmuch as they occupy some position in space, and
have a certain form, qualities which pertain to them in common
with all substances appreciable by the sense of sight, we pro-
ceed to notice the phenomena which result when exceedingly
narrow linear apertures are substituted for those of a circular
form. In conducting these investigations it was not unreason-
able to suppose, a priori, that if the size, the quality, and the
position of the object to be examined, the direction and the
intensity of the light which was used, the sensitiveness and
immediate response of the pupil of the eye to the minutest
variation in the quantity of light impinging on the retina, and
the refracting qualities of the transparent portion of the visual
organ, were each and all taken into account, so that a nice and
delicate adjustment of the eye to the light, and of the light as
well as of the size of the objects to the eye could be insured,
appearances perhaps beautiful, doubtless uncommon, and cer-
tainly interesting to the physiologist might be fairly antici-
pated. Such anticipations, have been so far realized as to
present a strong inducement to prosecute the subject with a
legitimate prospect of still greater success.

It is obvious that the phenomena which have occupied our
attention are chiefly due to the formation of shadows. For
when a divergent pencil of light proceeding from a small cir-
cular perforation in a card falls upon the eye, and when a
small object either transparent or opaque—a transparent cross
on a black ground, or a black cross on a transparent ground,

28 GORHAM, ON THE MAGNIFYING

for instance, is allowed to intervene; it is evident that a
shadow of the cross in the latter case, and an illuminated space
equivalent to the shadow in size and shape, in the former, is
portrayed on the retina of the eye.

The same kind of phenomena result even if no artificial
body be interposed between the eye and the source of light,
the pupillary aperture in this case constituting the transparent
space, and the 777s the blackened margin which gives it outline,
so that those rays which are not intercepted by this curtain,
pass onwards and ultimately form a picture of the pupil itself
at the bottom of the eye.

When an opaque object is held either in a beam of light
(bundle of parallel rays), or a pencil of light (rays proceeding
from or towards some point), it intercepts a portion of the
rays, and the space behind the object is in darkness. This
dark space is called the shadow of the object. Thus in figure
1, if the luminous body L emits a pencil of light which is
stopped in its passage towards the screen by a round piece of
blackened pasteboard, O, the dark space between this and the
screen, W, is the shadow.

Fig. 1.

A shadow may be received on a screen held near the object,
when its outline will be similar to that of the body by which
it is cast. Thus the shadow of the circle O (fig. 1,) is pro-
jected as a circle at S, on the white screen W.

The breadth of a shadow depends on the direction and dis-
posal of the rays of light when they are stopped by the oppo-
sing body. These may be parallel, divergent, or convergent. In
the remarks which immediately follow, I shall merely embody
so much under each of these heads as relates to the subject of
our present disquisition.

With respect to parallel rays it is to be observed, that the
farther the luminous body is from an object, the less divergent

POWER OF SHORT SPACES. 29

are the rays which fall from it upon the object; or the more
nearly do they approach to being parallel. ‘‘ From a (fig. 2)
there is much divergence, from 0 less, from c less still, and

Fig. 2

rays from a greater distance, as those represented by d and e,
appear parallel. If the distance of the radiant point be very
great, they really are so nearly parailel, that a very nice test is
required to detect the deviation. Rays, for instance, coming
to the earth from the sun, do not diverge the millionth of an
inch in a thousand miles. Hence when we wish to make ex-
periments with parallel rays, we take those of the sun.’’*
When such rays therefore are intercepted by an opaque body,
the breadth of the shadow, for we are not now speaking of its
length, is equal to that of the substance. ‘The student in per-
spective, is aware of this fact, and the fine effect of a good
landscape painting is to be referred in part to the strictness
with which this relation is observed by the artist.

If the rays are divergent, as when the light-emitting body is
very small, a mere point, the shadow is larger than the object.
Thus if L (fig. 1) be the luminous body, and O the obstacle,
the circular figure, S, on the screen, W, being a cross section
of a shadow which is continually increasing in breadth, is
larger than the object O. “The shadow of a hand held be-
tween a candle and the wall is gigantic; and a small paste-
board figure of a man held in a divergent pencil of light, and
near its source, throws a shadow as big as a real man. The
latter fact has been amusingly illustrated by the art of making
phantasmagoric shadows.” Divergent pencils are easily pro-
cured from a pin-hole, a taper, a street lamp, a carriage lamp,
&e.

When a convergent pencil of rays is obstructed by an opaque
body, the shadow is smaller than the object, and if not re-
ceived on a screen, would taper to a mere point. This is true
of the shadows of all the planets, and of the earth, because
they are less than the sun. It is exemplified when the moon

* See Arnott’s ‘ Elements of Physics.’

30 GORHAM, ON THE MAGNIFYING

falls into the earth’s shadow, and becomes eclipsed, or still
better in a solar eclipse, when the moon being at her average
distance from the earth, the shadow but just reaches the earth’s
surface. Thus if S (fig. 1) represent the sun, and O the moon,
that portion of the earth situated at L is in its shadow.

The shape of a shadow is regulated by the distance between
the object and the screen on which the shadow is received. If
this be great, the shadow bears no very definite relation in
form to that of the object. On the contrary, it is a mere irre-
gular darkened space, the boundaries of which are ill defined
and the shape distorted. Thus a leaf at the distance of a yard
or two from a wall, will, in the sunshine, give a shadow of in-
definite outline, having a round instead of an angular edge: a
leaf at a greater distance will produce a mere dimness, with an
outline scarcely distinguishable. Instances of a like kind are
afforded when the sun’s rays are obstructed by the topmost
branches of a tree, or the summit of a tower, or by the inter-
vention of passing clouds, which in their passage through the
atmosphere contribute so much to the beauty and variety of
the natural landscape, and are amongst those fleeting appear-
ances which elude the vigilance of the pencil.

When the screen is at a great distance from the obstacle, as
well as from the source of light, the shadow so far from taking
the shape of the obstacle, will resemble that of the luminous
body. Thus the shadow of an irregular body placed in the
sun’s light is circular.

If on the other hand the object is brought to within a short
distance of the screen, its shadow is so clearly defined as to be
directly recognized as an exact fac-simile, in shape, of the
body itself. A leaf nearly close to the wall casts a shadow
of a leaf.

“These observations regarding shadows are applicable to
the illuminated space formed on a screen by making the sun’s
light pass through an aperture.” This will be obvious, on
reflecting, that if a shadow or darkened space be well defined,
the adjacent, illuminated space must be equally so, and vice
versa. For these are contrasted conditions, each of which
causes the other to become visible. Neither light alone, nor
darkness alone, but only contiguity of both will enable us to
appreciate form. Hence light and shade are not only pleasant
to the eye, but both are absolutely necessary for the distin-
guishing of one object from another. For this reason, pro-
bably, the visual organ is ever intuitively on the search for
contrasts either of light, shade, or colour.

“‘When the screen is near the aperture, the illuminated
portion is similar to the opening ; but when the screen is suffi-

POWER OF SHORT SPACES. 31

ciently distant, it is similar to the luminous body. The in-
terstices between the leaves of trees are so many small irregular
apertures ; hence the cause of the numerous small bright circles
seen in a sunny day in the shadow of a tree, or still more dis-
tinctly in that of a grove.”’*

These simple laws which govern the projection of shadows,
and which have been seen to adapt themselves to individual
cases, may be easily verified. It is by their judicious combi-
nation, however, that we discover the best method of throwing
large and well-defined images of small, near objects upon the
bottom of the eye, which indeed constitutes the main design
of our inquiry. Thus of the three modes of illuminating the
object which have been enumerated, that is obviously the best
suited to our purpose which casts the broadest shadow. A
divergent pencil of light is therefore chosen. mn the next place
he position of the screen demands attention, for on this, as we
have seen, depends the definition as well as the enlargement
of the image. Now in the investigation of small, near bodies,
the screen cannot possibly be brought too close to the eye; in-
deed it is better to dispense with all artificial substitutes, and
to use that kind of screen only which nature has provided.
That is to say, the retina of the eye itself. This has accord-
ingly been adopted.

Again, recollecting the impossibility of distinguishing out-
line at all, except by contrast,—a mass of shade bounded by
light, or light by shade,—definite contiguous portions of the
retina are simultaneously affected with such impressions by
using a darkened tube to exclude the light, having small inlets
of determined size to regulate its admission at one end, and
openings to secure its transmission and exit at the other. In
this way, light and dark spaces are brought into direct conti-
guity with a well-defined line of demarcation between them.
Thus small objects are appreciable.

But, moreover, a shadow, like its substance, appears larger
as it approaches the eye; and the amount of enlargement is
regulated by the same law. Hence the one is equivalent in
this respect to the other: and as a shadow can be projected
directly in front of the eye, and received as an image, it is
thereby much magnified ; nevertheless at such short distances,
both shadow and substance, by any other process, would prove
invisible.

Here, then, we have within our reach the combination of
elements which appear necessary for examining small objects,
at very short distances from the eye; namely:—A darkened
retina, a diminutive object less than the pupillary aperture, held

* See Chambers’ ‘ Optics,’ p. 14.

32 GORHAM, ON THE MAGNIFYING

close in front of the eye, and a small divergent pencil of light.
From which it results, that the object when held in this pencil,
intercepts a portion of the light, and so casts a shadow greater
than itself, which shadow is rendered visible by contrast, still
further magnified by proximity, and eventually forms a visible
image at the bottom of the eye.

This principle of opposition or dissimilitude of shade, as
well as of colouring, called contrast, a term in very general use
in painting, is of universal application, because it contributes
not to the beauty only, but to the visibility of all objects.
Whether these opposite and contiguous colours or shades are
seen at the same time, and that this gives rise to the effect of
which we are all sensible, as is generally supposed, or whether
it results from attentively looking at the one and then at the
other in rapid succession, as was insisted upon by Sir Charles
Bell, it is not our province now to inquire, although there are
reasons for believing that both of these theories are correct,
and that the former holds good for minute objects near to the
eye, while the latter applies to larger ones at greater or com-
mon intervals. Dismissing hypothesis, however, we know that
with respect to bodies viewed at ordinary distances, if a
white figure be delineated on a white ground, or a black figure
on a black ground, neither is visible; in the first there is no
shade, and in the second no light, consequently there is no con-
trast. But the slightest variation of shade in the figures in
relation to their respective grounds, is sufficient to render each
of them definite. Hence the effect of a well-executed en-
graving, in which, although no colour is introduced, but merely
white and black to imitate light and shade, the appearance is
natural and satisfactory.

Two simple experiments will serve to show the importance
of attending to contrast with respect to the examination of
very near objects. By the first it is seen that although a well-
defined image is known to be certainly received on the retina, it
is invisible when the retina and it happen to be equally illumi-
nated. For this purpose, let perforations with a needle, the
tenth of an inch apart, and arranged in the form of a circle
of about a quarter of an inch in diameter, be made in a piece
of blackened cardboard (fig. 3). When brought close to the
eye, these apertures appear as a ring of luminous circles (fig.
4), the remaining part of the retina being in darkness. If now
around piece be cut out from the centre of the first card, a
portion as large, for instance, as that which is traced in outline,
but not actually excised in figure 3, so as to admit light
through the very middle of the perforated circle; it will be
found that while the discs are known to be still received on the

POWER OF SHORT SPACES. 33

retina of the eye as circles, inasmuch as the perforations remain
intact, and their position unaltered, they are not perceived as
such, because the surface at the bottom of the eye on which
the inner half of each falls is illuminated. Hence they appear
as semicircles (see fig. 5).

Fig. 3. Fig. 4. Fig. 5.

From which it is manifest, that however well defined an
object may be, and however geedred we may feel that its image
is actually portrayed on the bottom of the eye, it is not recog-
nised unless the contiguous surfaces are oppositely affected with
respect to light and shade:

The second experiment is the converse of the last, and goes
to prove that an image ts visible only when the retina of the eye
and the object are unequally illuminated. Let that portion of a
common sewing-needle which contains the eye be mounte: on
a slip of glass as if for the microscope; and let the paper
with Which it is covered, have a very small circular aperture
through which to examine it, thus (fig. 6) :

Fig. |

On holding the object close to the naked eye, it is found
to be altogether invisible. Nothing is seen but vacant space.
[t is matter of certainty, however , that the front rays are in-
tercepted, and that a shadow of the needle is therefore really
formed, but before reaching its destination, lateral rays stream
into the eye in all directions, which neutralise the shadow,
and so nothing is seen (fig. 7),

VOL. IV. D

34 GORHAM, ON THE MAGNIFYING

But when these lateral superfluous rays are excluded by
using a divergent pencil of light only, as in the diascope, the
shadow Wecomes visible ; and not only is the exposed portion
of the body of the neadili seen, but its eye is well defined, and
both appear considerably magnified (fig. 8).

Fig. 7.

Hence we may safely assume that all small bodies, whether
transparent or opaque, are undistinguishable when held e/ose
to the naked eye, in broad day-light, or diffused light of any
kind, but that if it were possible to distinauish hes while in
this position, they would appear magnified ; and moreover,
that this may actually be effected in many instances by the
artificial contrivances to which we have been endeavouring to
direct attention.

Fig. 8.

If a single object be retained in a given position before a
screen, it will intercept the rays emitte -d from any number of
separate luminous bodies, or sources of light, situated in front
of it, and so cast as many shadows. In has) wav the shadows
are multiplied. Thus if a finger be held within an inch or two
of the wall, and a number of tapers at as many yards, the pencils
of light iow, the tapers crossing the finger in different direc-
tions, and being interce pted by it, an equal number of shadows
are cast on the wall at intervals, related to the position of the

POWER OF SHORT SPACES. 35

taper. And if an opening of given shape were substituted for
the opaque object, as many illuminated spaces would be pro-
jected on the wall instead of the shadows.

This is effected on a small scale in the diascope, where small
perforations which admit the light are substituted for the
tapers, transparent designs on glass for the object, and the
retina of the eye for the screen on the wall.

Beautiful combinations on a large scale might be projected
on an extended surface by the multiplication of shadows, but
it is not our purpose to examine bodies at ordinary distances.

Hitherto but few experiments have been instituted for the
purpose of showing what kinds of images are produced with-
out a lens by bodies held close in front of the eye. It is not
likely, therefore, that all the necessary conditions shall be de-
vised until more care and attention shall have been bestowed
on this interesting branch of optics. Those which have been
mentioned in the former papers, and are resumed in this, may
possibly prove sufficient to provoke inquiry, inasmuch as they
are based on legitimate conclusions from the known laws of
optics, and are confirmed by experiments.

Small circular, as well as elongated openings for the trans-
mission of light were used by Grimaldi, Newton, Fresnel, and
Frauenhofer for investigating the phenomena, which light pro-
duces, when passing near the edges of bodies, a branch of
optics which is called the inflexion, or the diffraction of light.

A divergent beam of light was obtained by causing the
sun’s rays to pass through one of these apertures, and it was
ascertained that the shadows of all bodies whatever, held in
this light, were not only surrounded, but encroached on by
fringes of colours.

The experiments themselves were instituted for the purpose
of ascertaining the magnitude, form, colour, and number of
such fringes, when examined either by common or by homo-
geneous light.

The aperture, moreover, was held six feet or upwards from
the eye, and the fringes were seen either by throwing them on
a smooth white surface, where they could be examined with
the naked eye, or by looking at them with a magnifying glass,
in which case their peculiarities could be more carefully in-
vestigated.

According to Sir David Brewster, this curious property of
light was ably and successfully investigated by Fresnel, but
the finest experiments on this subject are those of Frauenhofer.*

* See Sir David Brewster’s ‘ Optics,’ Cabinet Cyclopedia ; also Herschel’s
‘'l'reatise on Light,’ § 735; also Edinburgh Cyclopadia, art. ‘Optics,’ vol. xv.,
p. 556; also ‘ Elements of Natural Philosophy,’ by Bird and Brooke.

D2

36 GORHAM, ON THE MAGNIFYING

The experiments illustrative of these curious phenomena in
which the light becomes bent into hyperbolic curves when
passing near the edges of bodies, present nothing in common
with those which form the subject of the present paper, in
which the short space which is caused to intervene between
the eye and the light precludes the possibility of detecting
the coloured fringes, supposing indeed that these were the ob-
jects of which we were in search. The only point of resem-
blance between them consists in the minuteness of the aper-
tures through which the light is admitted, and this serves to
show that by the same simple means different ends may be
accomplished. The mere peeping through a pin-hole without
some definite purpose,—some object to be examined,—some
particular theory to be investigated, were indeed a childish oc-
cupation, It is more than probable that some of the followers
of Newton were not much better engaged when we find the
celebrated Goethe afterwards using the words, si per foramen
exiguum, somewhat tauntingly in referenee to the fact of their
so frequently introducing this term into tlieir writings,

‘The curious figures now about to be described, and which
are produced by” the transmission of light through minute
narrow apertures, although related to nee which have been
shown to result from mere perforation, contrast with them,
nevertheless, in several important particulars, of which not the
least isleinie is the production of quadrangular planes which
are formed ge the light is partially intercepted during its
passage towards the eye, and which when multiplied by i in-
creasing the number of lines which produce them, appear to
fall together at their edges, and so to resemble hollow semi-
transparent figures of considerable beauty.

It may not “be withheld, however, that this part of our sub-
ject is, so far as | have yet proceeded, circumscribed within
narrow limits, being restricted chiefly to the formation of
images on the retina of the eye, of those solids known as paral-
lelopipeds, with composite forms, resulting from the multipli-
cation of the simple ones. The peculiar feature in the experi-
ments, consisting not so much in the novelty of the forms
themselves, as in their mode of production.

We proceed to consider the phenomena which light presents
when introduced through a narrow aperture held at a short
interval of an inch or two from the eye.

When an exceedingly small transparent space or aperture*

* Lines for this purpose may be drawn on glass, or cut through tin-foil.
When the former process is adopted, a small round disc of Indian ink is
laid on a circular piece of very thin glass, such as is used for the cover of
microscopic objects, and which may be procured of any microscope maker.

POWER OF SHORT SPACES. 37

made on glass, or in tin-foil, is held at the end of a darkened
tube ae two inches lone, oe examined by placing the eye
at the opposite end, and looking either at a white cloud or a
window blind on a sunny day, or at a lamp with a ground glass
shade, it appears altered in s7ze, shape, and transparency.

In eden to illustrate this, and to give an idea of the image
thus formed on the retina of the eye, let AA (fig. 9) be one of
these apertures fixed in the end of a darkened tube T, and let
AC, AD be rays of light admitted through it. This light will
diverge in lines AC and AD, and form an image CD at the
bottom of the eye.

If the same aperture be removed a few inches farther from
the eye, it presents nothing remarkable, and in no wise differs
in appearance from what we know to be its real form, namely,
a transparent line of exceedingly small dimensions. But if
he again made to approach the eye, it will appear, first, to be
much magnified ; secondly, to have lost its rectangular outline,
and to become rounded at either extremity; and thirdly, to
be traversed. by dark bands which take a direction parallel
to its long axis, as shown in fignre 9.

Fig, 9.

These glass covers are sold by the ounce, and are cut into squares or
circles of various sizes for the convenience of mounting. The Indian ink
might be painted on the glass by hand; but, after having made several
gross of such black discs, the author of these papers strongly recommends
a little instrument which, although constructed for a totally different
purpose, answers most admirably for this. It is the invention of Mr.
Shadbolt, and is described and figured in the second edition of Quekett’s
‘Treatise on the Microscope,’ p. 289. This instrument is nothing more
nor less than a miniature horizontal turning lathe, which is worked by
the finger, and by which, with the assistance of a camel’s-hair pencil, the
ink may be laid on in circles with the greatest nicety and expedition.
When dry the narrow line — with a finely pointed and slightly
moistened one-nibbed quill ; what is better, a style of brass drawn
along a flat ruler. When tin- foil is used instead of class, it may be held
ona piece of smooth flat lead; an aperture of the required size can then
be cut completely throuzh with the point of a penknife.

38 GORHAM, ON THE MAGNIFYING

The magnitude of the image is of course due to the proxi-
mity of the object to the visual organ, the rounded appearance
of its ends to the circular form of the pupillary aperture, while

the dark bands are produced by interference. These pheno-
mena claim a more attentive examination.

That the apparent magnitude of the luminous space is so
increased that the latter loses its linear form, and becomes a
plane, is only another example indeed of the general law in
optics, that all bodies, without exception, appear to grow
larger as they approach the eye, and to diminish as they
recede from it. But here an objection may be naturally raised
by one who has not familiarised himself with such inquiries,
or with the refracting powers of the eye. He finds from direct
observation, opportunities for which occur daily, that remote
objects do appear diminished in accordance with the law to
which we have referred, and with respect to objects at such
distances, he is inclined therefore to acquiesce in its correct-
ness. But on holding a small body, a needle we will suppose,
close to the eye, he is disappointed on discovering not only
that it is not magnified, but that it is altogether invisible.
Such an experiment has doubtless been performed by many,
and from its failure it has been concluded, and not without an
appearance of reason, that the body was held too near to the
eye to be visible, which however is not the case, as we have
endeavoured to show in a former experiment. But this very
failure indicates the necessity of means to an end. For if
haying satisfied ourselves theoretically that the eye is endowed
with certain capabilities, which we have reason to believe
there is a possibility of developing ; and if, on the application
of certain known laws in optics, some definite figure which it
was anticipated should certainly result, does not make its
appearance, we are driven to the conclusion, that the failure is
attributable to the experiment itself. A fresh trial, however,
is perhaps crowned with success, and it is thus that we become
possessed of new optical instruments, the value of which is
directly proportionate to the importance of the laws they are
designed to illustrate. For what are all optical instruments,

The glass or tin-foil should now be mounted on a piece of cardboard of
the required dimensions to fit the diascope, and having a hole about one
quarter of an inch in diameter punched from its centre. For this purpose
the thin tracing paper used by architects is the best, as it answers the
double purpose of keeping the glass in its place, and preventing too much
light passing through the apertures.

The dimensions of these apertures should be about the 1-L5th of an
inch by. the 1-185th of an inch, or nine times as long as broad (9: 1

ys): These dimensions can be easily ascertained by a micrometer
ith the aid of a microscope.

POWER OF SHORT SPACES. 39

but material combinations which serve to elucidate funda-
mental principles in optics by direct experiment ?

When one of these apertures, only the 1-200th of an inch
broad, is brought close to the eye, its apparent size is about
two inches. This is easily proved by observing that the
breadth of its image covers that of a line two inches long,
held up for the purpose of comparing the two at an interval
of ten inches, the distance at which we are accustomed to
view ordinary objects in order to gain an idea of their sup-
posed extension in space, and so to guess at their real magni-
tude. If this distance of ten inches were always preserved,
and if surfaces whose real dimensions are required were always
compared with a scale held at such a distance, the eye might
become instructed to appreciate relations of magnitude with far
greater accuracy than it has hitherto attained.

The comparison of the image of a very small object in
close proximity to the eye, with that of any larger object at
the usual distance for distinct vision, thus affords a correct
method of measuring the apparent increased magnitude of all
small bodies ; and it cannot be too strongly impressed on the
mind, that on looking through any aperture, whether small or
great, it always appears as large as all we see through it.
This has been happily expressed by an eminent writer. “ If
you shut one eye and hold immediately before the other a
small circle of plain glass, of not more than half an inch in
diameter, you may see through that circle the most extensive
prospects, lawns and woods, and arms of the sea, and distant
mountains, You are apt to imagine that the visible picture you
thus see is immensely great and extensive ; but it can be no
greater than the visible circle through which you see it. If,
while you are looking through the circle, you could conceive
a fairy hand and a fairy pencil to come between your eye and
the glass, that pencil might delineate upon that little glass the
outlines of all those extensive lawns and woods, and arms of
the sea, and distant mountains, in the dimensions in which
they are seen by the eye.”

Since this was penned, the fairy hand and the fairy pencil
have both been actually discovered in the beautiful art of
photography.

2. The extremities of the aperture appear rounded or semi-
circular.—We have seen how a circular perforation considered
as aradiant point admits a divergent pencil of rays, the cir-
cular base of which forms a large round disc or image at the
bottom of the eye (fig. 10). Now as a line mathematically
considered is made up of a number of points, so a transparent
line may be assumed to consist of a number of radiant points,

AQ GORHAM, ON THE MAGNIFYING

each of which lying side by side in a linear direction will
produce exactly such a series of overlapping circles at the

Fig. 10.

bottom of the eye (fig. 11). Hence a small, narrow, transparent
slit for the transmission of light when brought very near to
the organ of vision, forms an image not of a line but of a
plane rounded at either extremity.

3d The area of the aperture appears to be traversed by longi-
tudinal dark bands.—** If we hold the band between the eye
and a bright cloud, or the ground-glass of a lighted lamp, and
open the fingers so as to admit the smallest portion of light,
we shall perceive similar dark bands intersecting the luminous
space at regular intervals.” * The explanation of this pbe-
nomenon is founded on the interference of light, which,
according to the undulatory theory, takes place when the un-
dulations meet in opposite phases; these being superposed
produce darkness.

We have now to examine the appearance of bodies held
close to the eye, and in the light admitted through small
linear apertures such as we have been describing.

* See Woodward, on ‘ Polarized Lieht.’

POWER OF SHORT SPACES. 4]

Bearing in mind that the image of a linear aperture is not
a line but a plane, and that this can be revolved by inserting
it in the distal end of the diascope, it will be seen that if the
object chosen for examination be a similar linear aperture
held close to the eye we obtain a second plane, the first of
which can be revolved in front of the second, and so the two
can be made to intersect at any angle.

In order to illustrate this, let the planes P and p (fig. 12),

—

about two inches apart, be inserted at the ends of a darkened
tube, and let a small linear aperture, a and d, be made in each
of them. Now by revolving the plane p, the one aperture
will intersect the other. "When common diffused light is
admitted through the further aperture d, the greater part
is intercepted in its passage towards the eye at E by the
plane P, but that which is transmitted will partake of the
form of the luminous space produced by the intersection of
the two. Thus when the apertures cross at a right angle, as
shown in the figure, the image which meets the eye is a square,
while it is han bie at all other angles.

This may be further instrated by cutting two oblong
pieces, exactly similar in shape and size, from the lid and
the bottom of a common pill-box.
When the former is revolved upon
the latter, the quadrangular planes
to which we have referred are easily
imitated (fig. 13).

Hence by holding two very nar-
row, linear apertures before the eye,
and examining them by diffused
light, all idea of mere linear exten-
sion is lost, and we obtain images
of the square and all possible varie-
ties of the rhomb.

It is worthy of notice that such planes do not differ in form

Fig. 13.

42 GORHAM, ON THE MAGNIFYING

from the modifications which a square undergoes in obedience
to the laws of zsometric perspective ; and it is obvious that
if we are enabled to form any kind of rhombic plane at plea-
sure, by the mere revolution of one narrow transparent line
upon another, we can by simply multiplying these lines mul-
tiply also the planes, which when united at their edges will
present every appearance of a geometric solid.

And as a single line held close to the eye appears by in-
tersection as a single isolated rhomb, so two or more such
lines will form as many images, the relative position of which,
as well as their number, can be regulated by that of the aper-
tures which produce them.

If, for example, three fine transparent lines are projected in
the form of an equilateral triangle, sufficiently small to be
enclosed within the boundaries of a circle not bigger than the
pupil of the eye (fig. 16), and if such an object be held close
to the eye, and examined by the light admitted through the
single aperture at the distal end, its image will be that of the
triangular prism (see fig. 21, Pl. IV.).

On revolving the distal end of the instrument, which con-
tains the single aperture, the prism will appear in a variety
of aspects, four of which are shown in the figs. 21, 22, 23,
24, Pl. 1V., in which the image is depicted as seen at each
quarter of the circle.

In order to insure the proper effect, it is essential that each
object (that which is held at the near or ocular extremity of
the instrument) shall be mere transparent outline (figs. 14 to
20), in contradistinction to many of those which were exa-
mined by the light from the circular perforations, and which
consisted of considerable surfaces of illuminated space.

A few of the outlines, which I have found to bring out the
most satisfactory results, are given in the annexed figures

(figs. 14 to 20).
Fig. 14. Fig. 15. Fig. 16. Fig. 17. 18. Fig. 19. Fig. 20,

Fig. 14. The straight line.
15. Two straight lines meeting at 60°.
16. Three straight lines meeting at 60° (the equilateral triangle).
17. Four straight lines meeting at 90° (the square).
18, Four straight lines meeting at 60° and 120° (the rhomb).
19. Six straight lines meeting at 120° (the regular hexagon).
20. The circle.

The first of these objects is converted into the rhomb or the

POWER OF SHORT SPACES. 43

square, the second into two rhombs which are united at their
edges, the third forms the triangular prism, the fourth presents
an image of the cube, the fifth of the rhombohedron, the sixth
of the regular hexagonal prism, while the seventh forms a very
beautiful image of the cylindrical tube. All these figures
appear hollow, and their terminal planes are filled in by the
imagination.

Hitherto we have assumed the existence of a single linear
aperture at the distal extremity of the instrument, and hence
the production of a single image; but we can by increasing
the number of the apertures multiply the images, just as when
an object is held in the pencils of light proceeding from many
simple perforations, and from the same cause.

The relative position and distance of the apertures will also
regulate the disposition of the images ; thus if they are arranged
at regular intervals the images will be so also, and if in rays
proceeding from a common centre the images will radiate in
like manner. Several composite forms of considerable beauty
are thus produced.

If, for example, a small hexagon drawn in transparent out-
line (fig. 19), be viewed in the light admitted
through several alternating and equidistant linear
apertures, thus (fig. 21), there will be seen the
images of as many regular hexagonal prisms
having the same relative position ; and the result-
ing compound form will present a_ beautiful
honeycomb appearance, as in the following figure (fig. 22).

If a transparent circle in outline (fig. 20) is substituted for
the hexagon, the resulting form presents an analogous arrange-
ment of cylindrical tubes, as in fig. 23.

Fig. 21.

Fig. 22. Fig. 23,

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Were I not afraid of tiring the patience of my readers, I
might here proceed to describe and delineate a considerable
variety of beautiful figures, which are produced when the
apertures at the most distant extremity of the instrument are
tinted with different colours. The introduction of tints in

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44 WENHAM, ON THE SAP-CIRCULATION OF PLANTS.

this way merely modifies and does not alter the results, and
sufficient has been said in the former papers to show that the
beauty of each image is much enhanced by the process, But
Tam not dammindral that, however interesting the results of
these simple experiments with mere etc tie light may be
to myself, it would be encroaching on the pages of the ‘ Micro-
scopical Journal’ to enter more into detail on this part of my
subject. Neither does it appear desirable to attempt to give
an air of importance to a set of phenomena which, saving that
they constitute legitimate illustrauions of the subject in hand,
have at present scarcely more than their novelty and beauty
to recommend them.

Nores and Osservations on the Sar-Circutation of Pants,
By F. H. Wena.

SrncE my communication in the last number of this Journal,
“On the Circulation of the Sap in the Leaf-cells of the
Anacharis Alsinastrum,’ 1 have continued some investigations
on non-aquatic plants, with the view of ascertaining the
relation or analogy, that the phenomena of their circulatory
movements display, towards the subject of my former paper,
and to each other respectively.

I must, however, remark in the first place, that the ex-
amples have been examined in a very random imanner, for |
take up the microscope at uncertain periods, merely as a
means of recreation, and make no pretensions to that order
and system, which alone would allow the efforts of my pen, to
find a place with those of a scientific and professed botanist.
I am merely desirous of recording some facts which I believe
have not before been noticed.

The movements of circulation are best seen in the hairs of
plants, as the transparency and uniformity of their substance
allows their internal mechanism to be very readily distin-
guished. I had commenced a list of the most remarkable, and
after extending the catalogue to upwards of one hundred, I
concluded that the difficulty was to find the exceptions, for
hairs taken alike from the loftiest Elm of the forest, down to
the humblest weed that we trample beneath our feet, plainly
exhibit their circulation. Even hairs from the upper surface
of a blade of common Couch Grass (A gropyrum repens) display
the sap-movement with singular beauty and distinctness,
considering the minuteness of the object; (the intermediate
diameter being less than 1-1000th of an inch). The particles

WENHAM, ON THE SAP-CIRCULATION OF PLANTS. 43

may be seen traversing straight from the base towards tlie
apex of the hair, and returning again by the opposite side.

The circulation in the hairs of the Groundsel (Senecio
vulgaris) was first announced by Mr. Holland, as a discovery
made by his triplet microscope, and it is a Feluaeicqbiles instance
of what his instrument was capable of performing, for out of
the multitude of vegetable hairs in which the sap-motion can
be seen, I consider this to be one of the most difficult ; for
with our best compound microscopes, it requires careful ma-~-
nagement, and a trial of several fresh specimens before it can
be shown satisfactorily.

Hairs that exhibit circulation may be taken from all parts of
the plant, as the leaves, flowers, stalks, and fruit, and even from
the ripening seed-pods as in the Snap-dragon (A ntirrhinum)
and White Mustard (Sinapis alba), &c. It is important that
the specimens should be gathered from a portion of the plant,
in a healthy and vigorous state of growth. The time is also
of some consequence, the motion of the sap being generally
most rapid about mid-day. The specimen must be examined
as soon as possible, and the hairs detached without touching
them, by tearing them off with a portion of the cuticle of the
plant to which they are attached, by means of a fine-pointed
forceps. If the hair itself is grasped the destruction of its
vitality is the usual consequence. The object should be
instantly placed in a thin glass compressor with clean water,
using a good eighth object-glass and an achromatic condenser
having a series of diaphragms. Daylight is infinitely
superior to artificial illumination, and I have found it much
preferable to use a right-angled prism instead of the ordinary
plane mirror.

In cold dull weatber, a well-known object will sometimes
fail to exhibit its circulatory movements ; in such a case, it
may be called into activity by means of the natural stimulus
of heat. In applying this the object need not be removed
from the microscope, as a stream of hot air may be blown on
to the upper or under surface of the thin covering glass,
until the sap current is seen to move, by means of a metal
blowpipe, or the stem of a tobacco-pipe, previously heated in
the flame of a spirit-lamp. Some plants always require
the application of an increased temperature, in order to show
their circulatory movements. The hairs of the Helianthus are
a good example of this.

In the hairs of the numerous variety of plants that display
the sap-circulation, each species exhibits somewhat different
and peculiar features, which may be considered, in a degree,
characteristic throughout the plant; in some, single lines of

46 WENHAM, ON THE SAP-CIRCULATION OF PLANTS.

sap-currents extend the entire length of the cells or hairs, and
in others they are divided into an irregular network of ramifica-
tions, which shift their positions with considerable celerity, the
diversity of the phenomenon, perhaps, depending in some
measure, upon the constitution and fluidity of the sap, for
where this is rather glutinous the current traverses in the
form of a sluggish uniformly moving sheet or layer, lining
large portions of the interior of the cell ; I may mention hairs
from the Elder (Sambucus niger) as an instance of this.

In all cases where the sap-motion is seen in the hairs of a
plant, the leaf-cell displays analogous peculiarities, provided
the cuticle is not too opaque, or strongly marked to obstruct
vision. The cells are best obtained, by tearing off a layer of
the cuticle from the stalk or midrib of the leaf, and must then
be examined as speedily as possible, for the specimen loses
its vitality much sooner than the hairs. ‘There is scarcely a
portion of a leaf-cuticle possessing the requisite trans-
parency, taken from any plant wherein I have not discovered
indications of circulation; even where there is no direct
motion of particles to be seen, on account of their minuteness,
the existence of circulation may still be known, from the fol-
lowing fact:—The active corpuscles, which are the primary
cause of all the circulatory movements, are remarkable for
their high refractive power, both on their completion, and in
different stages of formation, and when arranged in a moving
train, they appear as bright lines across the cell.*

Many specimens of leaf-cuticle, in which at first no move-
ments whatever can be discovered, exhibit these lines, which

* As these observations were intended to be exclusively confined to the
sap-circulation, I have been desirous of recording them in the simplest
manner possible, and have therefore avoided technical expressions ; what
I have termed “the investment of active corpuscles,” has been known
as “protoplasm,” or “cell-mucus.” It may be doubted whether these
terms are strictly applicable, or truly represent that which in reality
consists of a multitude of particles, possessing individual activity and
differing in size, and probably in chemical constitution, according to local
position and the variety of plant-substance and tissue with which they
are ultimately destined to combine, such as cellulose, and the loose con-
tents of the cell, as chlorophyll- and starch-granules, the latter being most
evidently formed by the successive deposit of external layers upon a
central nucleus.

I may also remark, that it was formerly supposed, and some even now
retain the same opinion, that the ‘‘ circulation,” ‘ rotation,” ‘‘ gyration,”
or “‘cyclosis,” in the vegetable cell, both in its early development, or
growing stages, was in some way connected with a central nucleus, also
kept in rotation, and termed the “‘ cytoblast.” I consider this supposition
to be entirely fabulous, for whenever I have occasionally observed such a
nucleus, it has either been formed by an accidental conglomeration of some
of the cell contents, or by morbid conditions,

WENHAM, ON THE SAP-CIRCULATION OF PLANTS. 47

on being carefully watched, are seen to alter their relative
positions, a condition evidently depending upon progressive
motion. Most leaf-cells, of course, contain chlorophyll-gra-
nules; I have occasionally seen a few of these kept in a
continual motion by the sap-currents, but never in any in-
stance with the same degree of vigour and constancy, as in
aquatic plants. In the cells of the common Plantain (Plan-
tago) a few chlorophyll-granules are sometimes seen in motion,
This plant furnishes an excellent object, as the cuticle from
the stalk or midrib of the leaf shows circulation, both in the
hairs and cells at the same time; the sap-motions round the
latter are occasionally quite as plainly seen as in the Anacharis,
but more frequently the current is one of extreme tenuity,
and travels round the cell-wall with great velocity.

In the cells of the Horse Thistle (Cnicus) 1 have also seen
the chlorophyll-granules carried along with considerable vigour
by the sap-currents: this plant exhibits a remarkable variety
in the phenomena of circulation, The glutinous corpuscles
are connected together in the form of a line, or rope stretched
across the cell, exhibiting a loose vibratory motion as if it
were being shaken at one end, while particles and, occasionally,
chlorophyll-granules, are carried forward in a manner resem-
bling beads along a string.

Having now noticed some of the distinguishing peculiarities
of the circulation in a few of the plants that have come under
my observation, I will offer some brief remarks on the vital
principle of vegetable growth and motion. I had stated in
my former paper that the cell-circulation, or what is termed
‘“‘ rotation,” in the Anacharis, is entirely caused by the com-
bined effort of a multitude of active corpuscles; the same fact
equally applies to every other plant that J have examined ;
and subsequent experience has given me some further insight
into the nature of these atoms; they evidently derive their
origin and formation from the most fluid portion of the sap,
with which every cell is filled, and which pervades all other
portions of the plant tissues. In every stage of their growth
they individually possess the motion peculiar to active mole-
cules, but when in combination in their containing cell, this
motion zs converted into one of direct progression from some
cause that I am not able to explain. I have tried by various
means to effect a similar motion artificially in ducts and tubes,
with both organic and inorganic active molecules, but without
success ; I therefore conclude, that the progressive movement
is not due to any mechanical conversion of one force into
another, but arises from some unknown property, connected
with the vitality of the plant. I have witnessed the effect in

48 WENHAM, ON THE SAP-CIRCULATION OF PLANTS.

numberless instances in both the cells and bairs of plants.
An isolated active corpuscle is seen detached, quickly per-
forming its vibrations with constant activity, until its progress
becomes arrested by one of the various ramified currents which
traverse the hair; at which instant the vibratory movements
totally cease, and the particle visibly assists the direct-furward
motion of the current by its vital energy.

I observed with regard to the Anacharis, that after having
been kept in a cold, dark place for one or two days, usually
pot a symptom of circulation could be discovered, the cor-
puscles having collected together in heaps, with the component
particles in a state of torpidity, and on being again exposed
to the stimulus of ight and heat, they recommenced their
active motions, This effect is still more remarkable in some
non-aquatic plants; and a practised eye may at once detect, by
the state of the cell-contents, whether the plant is in a state
of repose or hybernation, as the corpuscles will in this case
be seen collected together in several gelatinous-looking clots,
their dormant vitality being again called into existence, by
the same method as described for the Anacharis. Light is
also quite as necessary a stimulus as heat; for in a recent
experiment on this plant I interposed four thicknesses of blue
glass between the achromatic condenser, and luminous source,
(bright skylight,) thus entirely intercepting the heating rays,
and yet, in spite of this intervening obstacle, speedily suc-
ceeded in exciting the movements of circulation.

The microscope discovers that in every portion of the plant
each duct, cell, or vesicle, that is filled with sap, also contains
active corpuscles, apparently differing in dimensions and
substance according to locality. As regards the office that
these bodies fulfil, it may be inferred that either they are the
vehicles that convey nourishment to different portions of the
cell-tissues, or that they themselves are deposited, to form
the various structures of the plant. I will give an illustra-
tion of the latter effect. The annexed woodcut represents one
of the hairs or spines taken from the stalk of the Anchusa
paniculata (Boraginacee), an ornamental flowering plant of
rapid growth. The growth of the spine is performed by the
addition of successive layers to the interior, as shown at a, a,
which eventually fill up the apex and render it solid: the
method by which this action takes place is as follows:—A
dense current of corpuscles are seen to travel along one wall
of the spine, constantly returning by the opposite side, repre-
sented ath b. Atc, where the deposition occurs, there is a
considerable accumulation, and at the boundary, where they
are converted into the substance of the spine, a number are

WENHAM, ON THE SAP-CIRCULATION OF PLANTS. 49

seen to be adherent. Some are but recently deposited, while
the underlying ones are in various regular
stages of transition, gradually losing their
form and outline, and finally all traces of hh
individuality become lost ; and by a species i
of induration the particles become united His
and identified, with the solid body of the li
spine, ih

In very many specimens of this object
that I have submitted to examination, the
deposit has been so rapid, that there was
not sufficient time for the complete con-
densation of the component corpuscles.
In these instances a number of them have
been caught and loosely enclosed in one
or more cavities, as shown at d d, and,
with the exception of being perfectly
motionless, the contained corpuscles are wig
the exact counterpart of those circulating 4
in the spine. The walls of the containing 7 :
cavities do not possess a definite outline,
because they are lined with corpuscles in
all their transition stages.

I have now brought forward the chief
substance of my notes on this subject ;
they were made without previous study,
and with an intention to avoid all hypo-
thesis, and to confine myself to as clear a
description as I could give, of any facts
that the microscope might reveal.

There is yet very much to be learned
respecting the sap-circulation of plants,
particularly in their different organs ; but
the inquiry is attended with much difficulty,
from the necessity of our being compelled
to examine detached and lacerated specimens. In many ex-
amples this is not of material consequence, as in some aquatic
plants, for in these the cells retain their independent motions
and individuality, long after their separation; but in non-
aquatic plants the case is somewhat different, for the mutual
dependence of neighbouring cells is so considerable, that in
many instances, death is the immediate result of detaching
them, and the movements immediately to be seen under the
microscope, are probably only the lingering remnants of
vitality, and do not perfectly represent the circulation in the
uninjured plant.

VOL. IV. E

vv _

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Rie et

Sas
t&%

acu) SG TAN

Sys

50 WENHAM, ON THE SAP-CIRCULATION OF PLANTS.

Lest it should be imagined, that I advocate the long-ex-
ploded theory, that supposed all vitality to originate with
active molecules, I will venture, in conclusion, to make a few
brief remarks in relation to them. The existence of active
molecules has been known in a very early age of the micro-
scope, but the first definite information on the subject, was
given in the paper of Dr. Robert Brown, published in the
‘Edinburgh Journal of Science,’ for July, 1828. These
observations rather tended to favour the above theory than
otherwise, from the circumstance of his connecting together,
without due distinction, both inorganic and organic molecules,
some of the latter being obtained from actual living plants.
The difference between vital and inorganic molecules is im-
mediately perceptible, when submitted to the action of proper
tests. Active molecules may be obtained from very many
different mineral and inorganic bodies, as sulphur, limestone-
rock, ashes, and even burnt clay. Their motions have been
successively attributed to the influence of mutual attraction,
caloric, and electricity ; I have tried several experiments upon
them with these two agents, but without obtaining definite
results ; nor am [| yet satisfied with any explanation that has
hitherto been given of the cause of their activity. I merely
mention this in order to show the very wide difference exist-
ing between these and the active molecules, or rather cor-
puscles, contained in the vegetable cell; to all appearance
their movements are identical, but the motion of the latter
may be entirely suspended, or awakened, by the range of
temperature consequent upon ordinary atmospheric changes.
Their vital activity is immediately destroyed by a small trace
of hydrochloric or sulphuric acid. The motion is increased by
the agency of a slightly-alkaline solution, particularly that of
ammonia; but this stimulant added to excess becomes a
poison, and destroys the principle of activity.*

On the other hand, active molecules obtained from a pow-
dered brick-bat, for example, may be exposed to considerable
differences of temperature, without their motions being
affected by it; and provided there is no chemical decom-
position, they exhibit the same degree of energy, whether the
solution be either acid or alkaline.

* A fact curiously in accord with what has been observed by Kolliker,
with respect to the action of the same re-agents upon the spermatic fila-
ments of animals.—Vide ‘ Quarterly Journal of Microscopical Science,’
vol. iii., p. 293.—{ Eps. j

CURREY, ON THE PHYTOZOA OF ANTHERIDIA. 51

Hartie on the Puytozoa of AnruEripiA. By F. Currey, Esq.,

M.A
Was wird aus der Schwiimfaden der Antheridien? Dr.

Hartig has devoted a section of his essay on the develop-
ment of the vegetable cell, now in course of publication in
the ‘ Botanische Zeitung,’ to a consideration of the above
question, and the results he has arrived at are highly curious
and interesting. Should further investigation lead to a con-
firmation of Dr. Hartig’s views, the consequence will be that
several genera of the Infusoria must be transferred to the
vegetable kingdom. Dr. Cohn’s lately-published observations,
will have already prepared the minds of the friends of the
Infusoria for such a result, and will cause the blow aimed by
Dr. Hartig at the animal nature of some of Professor Ebren-
berg’s favourites to be less keenly felt. In the following
pages we purpose giving the substance of Dr. Hartig’s paper,
which is of great interest to microscopical observers; the
experiments are such as may be repeated without difficulty.

The author commences by observing that the phytozoa of
the Characee are best suited for the observations in question,
inasmuch as, when placed upon a slide in water, they are
then in their natural element; but numerous observations
made upon the Antheridia of Chara, Nitella, Polytrichum, and
Marchantia, have \ed to the same results, and the last-named
plant has the advantage of affording the easiest opportunity
of procuring a large quantity of phytozoa free from the
admixture of foreign bodies. To effect this, the disk in
which the Antheridia are imbedded should be washed repeat-
edly with distilled water, its upper surface removed, and fine
transverse sections taken from beneath. If these sections be
placed upon a slide in a drop of distilled water, a vast number
of phytozoary cells will escape from the segments of the
Antheridia into the surrounding water.

A dozen, at least, of such sections should be prepared, and
in order to prevent evaporation they must be placed upon
clean oiled-silk, and covered with bell-glasses lined with
moist blotting-paper. If these preparations be examined
twice or three times a day, certain changes will be observed
to take place in the phytozoa; and since these changes run
through the whole mass of the phytozoa in each preparation,
they must be considered as normal.

The above experiments constantly repeated have led uni-
formly to the following results.

The free phytozoa are very soon drawn to the edge of the
drop of water (probably by the effect of evaporation), and

E

52 CURREY, ON THE PHYTOZOA OF ANTHERIDIA.

form there in the first instance a skin which covers the sur-
face of the water. The form of the phytozoa is distinguishable
in the granulated and serpentine disposition of the granules
of this skin. Beneath this skin other phytozoa are seen in
the state of motion peculiar to them. In the course of a few
hours these latter phytozoa assume the form of Ehrenberg’s
genera Spirillum and Vibrio differing from that of the phytozoa
only in the manifest articulation, and in the absence of cilia.
At a later period the granulated skin extends from the margin
over the whole surface of the drop of water, and the phytozoa
underneath this skin are now seen, without any cessation of
their motion, to assume forms similar to those of the Spirilla
and Vibriones. The forms of Vibrio rugula and V. prolifera
are most frequent. :

After the first twelve hours all the phytozoa disappear,
and there remain only the Spzrilla and Vibriones in number
proportionate to that of the original phytozoa.

The Spirilla and Vibriones exist for a very short time.
After twenty-four hours most of them, after forty-eight hours
all of them, have become disarticulated. The whole drop is
now rendered milky and turbid by numberless globules
similar to Monas crepusculum in a state of active motion.

The observer may be fully convinced that the forms of Spi-
rillum, Vibrio, and Monas, do not originate from extraneous
germs, and that they are not formed out of shapeless matter,
but that they originate from the undecomposed substance of
the phytozoa. The unusual rapidity of the transformations
by which the process is kept, as it were, continually before
the eye of the observer is a favourable circumstance in these
observations.

It is an important circumstance that Spirillum does not
originate from Monas, but always Monas from Spirillum.

After forty-eight hours, it frequently happens that amongst
the moving monads which have hitherto been uniformly dis-
tributed through the water, small groups consisting of several
hundreds of them are to be seen in which the primary active
motion has ceased. Shortly afterwards a sharply-defined
hyaline skin is formed round these groups, and, as it would
seem, by the amalgamation or conjunction of the exterior
molecules; by this means the young Ameba (Proteus) is
formed. This transformation takes place pretty regularly
towards the end of the third day.

The original size of the Ameba is 1-300" in diameter. In
the course of three or four days it grows to about the size of
1-100". This species differs from the Amedbe hitherto de-
scribed in the fact that the inner portion of the body which

CURREY, ON THE PHYTOZOA OF ANTHERIDIA. 53

bears the granules is much smaller than a certain hyaline
covering, which covering is closely attached to the hinder
part of such inner portion, but extends far away from the
anterior part, and, in addition to this, the progressive motion
in this species originates in an alternate enlargement of the
longitudinal and transverse diameters, and is so slow as to
amount at the utmost to no more than 1-40'" per minute.
The form of the body resembles that of Ameba princeps
(Ehrenberg). The vesicle in the hinder part of the body,
which was first described by Ehrenberg as a mouth, and
afterwards as an ovarium, is also present.

After four or five days the Ameba assumes a spherical
shape and becomes motionless, the vesicular body expanding
and contracting rapidly as before, in a manner similar to
what takes places in many Vorticelle. These spherical mo-
tionless Amebe are then for the most part united by a
mucilage into groups of from ten to twenty. The mucilage
appears to be produced by the decomposition of a cast-off
external skin.

In about a fortnight after the commencement of the experi-
ment a green point appears in the interior of the spherical
colourless body of the Ameba; this point gradually increases
in size until it fills up the entire hollow of the Ameba, and
after becoming covered with a cuticle it escapes in the form of
an elliptical bright-green cell, 1-300" in diameter, resembling
a Protococcus. It exhibits a round transparent cavity, devoid
of chlorophyll, corresponding in size and position to the
vesicular body of the Ame@ba, and resembling at its colourless
apex the motile gonidia of Cladophora. A few days later
the elliptic or roundish cell lengthens, a formation of trans-
verse septa commences, and the uni-cellular alga becomes an
articulated one.

All these transformations of phytozoa into Spirilla, Vibri-
ones, Monads, Amebe, unicellular and articulated Alga, may
be observed, not only in the detached phytozoa, but in those
which remain in the interior of the sections of the Antheridia.
In those Antheridia of which the phytozoa are not fully ripe,
the Amebe are seen to originate in the middle of the internal
mass of phytozoary cells; some of them make their way
out through the softened mass of cellular tissue, but others
remain in the interior of the Antheridium until their develop-
ment into an articulated Alga.

Contemporaneously with Ame@ba, and often earlier, there
may be seen amidst the mass of Monads bodies very similar
in form and motion to the genus Bodo (socialis), and which
increase by transverse division; they have the front end

54 CURREY, ON THE PHYTOZOA OF ANTHERIDIA.

furnished with a long whip-shaped antenna or cilium similar
to that of Euglena. At their first appearance, their motion,
their change of form, and their whole exterior, differ so little
from the earliest states of Ameba, that at this period they
cannot be distinguished. In these early stages they both
resemble Chlamidomonas destruens of Ehrenberg.

The above forms uniformly make their appearance, and
always in the succession above described. It is true that
other forms, such as Uvelle, and even Leptomitee and Peri-
coni@, are sometimes met with, the germs of which may have
been imported by the atmosphere during the observation, but
these organisms, which always appear singly and after the com-
mencement of the observation, do not interfere with the above
results, when we consider the immense number of the phytozoa
and their uniform and contemporaneous transformations. If
about a dozen preparations are made, and if they are carefully
covered with a bell-glass after each observation, and if care
be taken not to extend the observations for too long a time at
once, at least half of the preparations will be free from all
admixture of foreign organisms.

Dr. Hartig proceeds to remark upon certain transformations
similar to the above, which occur in the motile gonidia of
Cladophora, and he also notices certain Amebe which originate
from the phytozoa of the Characee. Want of space prevents
us from entering into the details of these latter observations,
but it may be observed that in the Amebe of the Characee a
remarkable circulation is to be seen similar to that which
occurs in the cells of Chara. Diatomacee have been observed
to force their way into the interior of these Amebe, and to be
carried round with the current of the cell-contents. In con-
clusion, the author puts the following questions :—Does
Ameba belong to the animal kingdom, or is it a stage of
vegetable development? Assuming the latter, does this
development ultimately lead_to the production of the same
plant from which it took its rise, or is the final stage of
development dependent upon external circumstances? Are
the phytozoa endowed with impregnative powers, and do they
only become converted into Spirilla in the absence of those
organisms upon which their impregnative powers are ordi-
narily exercised ?

ON A UNIVERSAL INDICATOR FOR MICROSCOPES. 5D

On a Universat Invicator for Microscores. By J. W.
Battery.

In the ‘ Quarterly Journal of Microscopical Science,’ vol. i,
p. 34, an ingenious contrivance for registering the position of
microscopic objects is described by Mr. Tyrrel ; a modifica-
tion of this, by Mr. Aymot, is given in a subsequent number
(1. c., vol. i. p. 301); and a still better arrangement for the
same purpose, suggested by Mr. Brodie and applied by Mr.
Okeden to his microscope, is described at p. 166 of volume
iil. of the same work. The last mentioned device can scarcely
be improved upon for convenience ; but there is one defect
which is inherent to all these inventions, viz., that they are
essentially selfish contrivances, of no use to any one but the
owner of the particular instrument to which they may be
attached.

The object of the instrument I propose is more comprehen-
sive than that of the “ Finders” above alluded to, being no
less than to make a Universal] Indicator, by means of which an
observer can so register the position of any number of objects
mounted upon slides, that when these are sent to a distant
correspondent the latter may be able by means of the Indicator
to find at will any of these objects, as easily as if he had the
identical microscope and “ Finder” by which they were at first
recorded. If such a mode of recording the position of objects
can be generally adopted that when the register is once made,
the record and the objects shall then be entirely independent
of the original instrument and observer, and applicable to any
microscope, it will tend to promote science not only by facili-
tating the interchange of specimens among naturalists, but it
will give to each observer’s collection, when properly regis-
tered, a permanent scientific value and utility which it could
have in no other manner.

The plan I have adopted is to make upon an engraved card
what may be considered as a transferable stage, having guide-
lines, by means of which the centre of the field of view of
the microscope, and the position of a slide when any object
upon it occupies this centre, may be given.

Plate V. shows the Indicator complete. The centre of the
field of view corresponds to the intersection of the horizontal
line C, D, with the vertical line E, F. On the right and left
hand of this centre the vertical axes B and A’ are placed at
distances of 4-5ths of an inch, and the axes A and B’ are
similarly placed at the distances of 6-5ths of an inch from
the centre.

56 BAILEY, ON A UNIVERSAL

The axes are then graduated as seen in the plate; the small
divisions being each 1-50th of the standard inch.

The dotted lines G, H, I, give the outline of what will be
referred to as the centre-piece.

Should it ever be desired to reproduce the Indicator by en-
graving or otherwise, the dimensions above given must be
most accurately preserved. The dimensions here given were
taken from the standard inch of the United States, belonging
to the State of New York, and preserved in the office of the
Superintendent of Weights and Measures in Albany. It is
the same as the English inch.

The slides on which objects are mounted to be used with
the Indicator must have guide-lines ruled on their under side,
as shown in fig. 1 and 2. The horizontal line parallel to the
lower edge, and passing through the middle of the slide, is
not continued over the portion of the slide which is to be
occupied by the objects and their glass cover. The distance
of each of the vertical lines from the middle point of the
slide is one inch. Great accuracy in the distance between
these lines of the slide is not essential when they are to be
used with the ordinary form of the Indicator as above given,
but it is desirable when they are to be employed as hereafter
described, with a modification of the Indicator applied to a
moveable stage.

The slides should all be marked with an arrow placed upon
their upper and right-hand corner, as shown in fig. | and 2,
to point out the edge which must always be kept in front in
using the slides upon the Indicator.

The Indicator is to be used as follows :—Cut out the centre-
piece with a thin-bladed knife, following the outline G, H,I;
then replace the piece cut out, and make a hinge for it along
the line G, H, by pasting underneath it a piece of thin paper
which will bear repeated folding, so as to connect it to the
rest of the card.

The Indicator being now ready for use, it must be firmly
secured to the stage of the microscope, in such a position that
its centre as given by the intersection of the lines C, D, and
E, F, when viewed as an opaque object, may be exactly in the
centre of the field of view. If the stage is a moveable one, it
must be kept stationary after the Indicator is properly centred.

The Indicator having been adjusted as above directed, the
centre-piece is to be turned down, and the instrument is then
ready for use, either to record new objects, or to find those
previously recorded. The slide is to be put upon the Indi-
cator, and guided either by the fingers or a moveable ruler,
so that when any object which is to be registered occupies the

INDICATOR FOR MICROSCOPES. 57

centre of the field of the microscope, the horizontal guide-line
upon the slides shall pass through the same numbers on two
vertical axes of the Indicator as remote from each other as
possible. In some positions of the slide the axes A and B’
can be used for this purpose ; in others A, and A’, or B, and
B’ must be employed.

The horizontal line of the slide being arranged, as just
directed, it will be found that at least one of the vertical guide-
lines of the slide will intersect the horizontal graduation. By
observing now the numbers at which the guide-lines respec-
tively stand, the record can be made. Suppose, for example,
that the horizontal guide-line ruled upon the slide intersects
the verticals of the Indicator at 48, while the right hand ver-
tical of the slide cuts the horizontal series of numbers of the
Indicator at 75; the entry to be made for this object in the
register would be written thus 43’; and whenever that particular
object is to be found either by the same Indicator or any other
copy of it, if the slide is placed at these numbers, and the In-
dicator is properly centred, the object must be in the field of
view. In the same manner any number of objects can be re-
gistered or found. If the slide happens to be so placed that
both of its verticals intersect the graduated portions of the
horizontal line C, D, the position of either one of them can
be recorded at will.

If a guide-line upon the slide falls between two divisions
of either scale, the fraction of the division may be estimated
with sufficient accuracy by the eye or a hand-magnifier and

1!
entered in the register. Thus the recorded position a
would mean that the vertical lines of the Indicator were inter-
sected at 1-8th of a division of the scale beyond 25, while the
vertical guide-line of the slide passed 1-4th of a division
beyond the number 34 of the horizontal scale, as nearly as
could be estimated.

It is convenient to let the lower edge of the glass slide rest
against a straight-edged guide-piece, which can be moved
parallel to the horizontal line of the Indicator. By pushing
the slide along this edge, all the objects on the same horizontal
line can be found without changing the position of the guide-
piece. By moving the guide-piece a little forwards or back-
wards another sweep across the slide may be made, and so on
until every object of interest is found.

By following the directions above given it will be found
that the recording or finding of objects by means of the Indi-
cator is very easily performed, and scarcely requires the time
which has been employed in describing the method. It is

58 BAILEY, ON A UNIVERSAL

believed that the explanation above given is sufficiently ex-
plicit to enable any one to use the Indicator ; but some addi-
tional remarks will now be made upon the reasons for adopting
the particular arrangement I have used, the modes of insuring
accuracy in manipulation, and the modifications of which the
Indicator is susceptible for individual convenience.

It was desired to make the instrument capable of universal
application, so simple that it could be adapted to any stage ;
so light and yet so strong that it could be sent without injury
by mail or otherwise to any distance; and, lastly, that the
different copies should be perfect fac-similes of each other
and reproducible at any time. Al] this is secured by having
the Indicator engraved upon a steel plate and printed upon
cards of uniform quality, and by taking the dimensions from
the standard United States inch, preserved in the office of the
Superintendent of Weights and Measures in Albany. In order
to extend the use of the Indicator to all cases which are likely
to occur, the graduation was arranged with reference to slides
three inches long and one inch wide, while it will answer
equally well for smaller ones. When these slides are not
covered with paper, and guide-lines can be ruled as above
directed upon the glass itself, the graduations necessary for
their use would only extend upon the verticals $ an inch
above and below the horizontal line, and upon the horizontal
line only 4 an inch outwards from the points 40 and 70; but
in order to provide for paper covered, or opaque slides whose
uppermost and lateral edges may be used as guide-lines, the
graduation has been extended considerably. It will be found
on trial that slides of the standard size, whether paper covered
or not, may be employed with the Indicator for the registra-
tion of all objects under a glass cover of a square inch in size,
which is quite as large as is likely to be used. In using cover-
ing glasses of an inch square it will be found necessary to
employ the horizontal numbers 0 to 50, and the verticals
A, A’, for objects towards the right of the cover, and the other
axes and numbers for objects towards the left. For a portion
of the objects under the cover, either set of axes and numbers
may be used at pleasure, provided that the verticals are chosen
as far apart as possible.

Two verticals on the same side of the centre should never
be used together, as a small error in observing the numbers
would have more effect in displacing the object from the
centre than if two axes at a greater distance had been em-
ployed. The reason for leaving a blank ungraduated space
between 50 and 60 on the horizontal line was to allow a fac-
simile of the Indicator to be engraved upon the stage of any

INDICATOR FOR MICROSCOPES. 59

microscope, the blank space being left for the portion of the
stage occupied by the aperture.

The guide-lines upon the glass may be ruled with a fine-
pointed scratching diamond, and be rendered more visible by
having graphite or black lead rubbed into them. Lines ruled
in this manner will answer for all except very minute objects ;
but in consequence of the widening of the lines by the chip-
ping up of the glass due to unequal expansions and contrac-
tions, the lines often become too wide and irregular for very
accurate adjustments. In such cases admirable guide-lines
may be etched upon the glass with the vapour of fluohydric
acid, and can be made of any required degree of fineness.
Tlie’ sohition of the acid should not be employed for the
etching, as it gives lines which are too smooth and difficult
to see, and which will not retain the black lead if rubbed into
them.

The power of the objective employed in determining the
position of an object for registration, should always be the
highest which can be conveniently employed ; while in search-
ing for an object already recorded, a power lower than that
employed in the registration may be used. The object then
must be in the field of view, and would be at the centre but
for slight errors in manipulation, or the want of perfect ad-
justment in the mountings of the object-glass. Care should
be taken to bring each object accurately to the centre of the
field of view, before recording it. It will then require an
error equal to half the diameter of the field of view to throw
it out of that field. For example, the field of view of my
3-inch objective, made by Spencer, includes two divisions of
the Indicator, and hence an error of nearly one division might
be made in placing a slide upon the Indicator by means of
its recorded numbers, and yet the object would be found in
the field.

It may happen that in transferring a slide from one Indicator
to another that the object when brought into sight by means
of its recorded co-ordinates will not appear well centred. If
this be due to slight differences in determining the centres of
the Indicator, and yet the record has been carefully made, it
is easy to correct for the difference in the following manner,
Move the Indicator with the slide placed at any recorded
position until the object comes into the centre of the field of
view, then secure the Indicator to the stage in this new posi-
tion, and all other objects recorded by the same Indicator
ought to be brought to the centre of the field of view by
means of the numbers as registered.

The convenience of the Indicator for individual use may be

60 BAILEY, ON A UNIVERSAL

increased by several slight changes. One of these consists in
removing the paper centre-piece, and replacing it either tem-
porarily or permanently by a glass plate bearing lines at right
angles to each other ruled very lightly with a diamond point,
and so adjusted as to coincide with the prolongation of C D
and E F through the centre. For all but the highest powers
there is no objection to having these excessively minute lines
permanently beneath the centre of the Indicator, as they do
not perceptibly interfere with the light, and it is convenient
to have them always in place. They can be ruled upon a
piece of mica or thin glass cemented to the hack of the
Indicator, or the latter may itself be cemented to a piece of
plate glass and the central guide-lines then carefully ruled.
Even for the highest powers these lines can be used in record-
ing the position of objects, which can then be found for study
by using an Indicator of the ordinary form. By a proper
arrangement, a moveable stage, with screws for vertical and
horizontal motions, may be graduated so as to correspond to
the Indicator, and yet preserve all the advantages of accurate
adjustment which the screws afford. For this purpose it is
necessary to observe that if the Indicator be placed upon the
stage and accurately centred, with its guide-line, C D, parallel
to the front edge of the stage, and a slide be then placed upon
the Indicator, so that its horizontal guide-line shall coincide
with C D, and the right-hand vertical gue ine stand at 70,
(7.e. in the position which would be recorded as $9’,) or its left-
hand guide-line at $$’; then a motion of the stage iteelé bearing
with it the Indicator and slide, or an equal motion of the slide
upon the Indicator and fixed stage, will bring the same point
of the slide to the centre of the field of view.

Therefore, by attaching to the stage in any convenient
manner graduations corresponding to those of the Indicator,
and by having lines corresponding to 3§’ and $$’ ruled upon
the stage, it will only be necessary to place the slide directly
on the stage at these numbers, the stage itself being set either
at $$! or s.r of its graduations. By turning the milled heads
of elie screws which give the vertical and horizontal motions
of the stage, the object can be brought into the field of view,
and recorded or found again by means of the numbers attached
to the stage; while the record may be used for any other
Indicator as if made in the usual manner. If the distance
between the guide-lines upon the slide agrees accurately with
that between 40 and 70 of the Indicator, the slide, when placed
upon the moveable stage at either 59’ or 3%’, will need no
displacement for the whole series of numbers; but if this
distance do not agree, the slide must be put with its left-

INDICATOR FOR MICROSCOPES. 61

hand vertical coinciding with the left-hand vertical of the
stage for all numbers from 0 to 50 of the horizontal series ;
while from 60 to 110 of the same series the slide must be set
so that its right-hand vertical coincides with the right-hand
vertical of the stage; in each case the horizontal lines of the
stage and slide being adjusted to coincide. By observing this
rule the necessity of perfect accuracy in the position of the
guide-lines upon the slides is done away with.

There are some objections, but not insuperable ones, to the
moveable stage Indicator as above described. In the first
place, the stage as usually made has its motion too limited to
correspond to the whole range of the Indicator; and secondly,
the guide-lines ruled upon the stage for one object-glass may
not answer for other powers on account of slight inaccuracies
of mounting.

The stages can doubtless be constructed to give as wide a
range for motion as required, which will do away with the
first-mentioned objection. The second may be removed by
placing an Indicator upon the upper plate of the stage when
the latter stands at 4°’, and adjusting it so that when well
centred for the power employed the line C F shall be parallel
to the front edge of the stage. The slide being then placed
upon the Indicator, with its guide-lines at 5%’ or 22’, the re-
maining motions may be made with the screws in the usual
manner, and the numbers may be read off from the stage-scales
instead of the Indicator,

The above-mentioned modifications are excellent for in-
dividual convenience; but for the general purposes of science,
the comparable, transferable, reproducible Indicator, in its
simplest form, must be preserved ; and it is only in that form
that it deserves the name, suggested by a friend, of the Uni-
versal Indicator.

As a proof of the utility and accuracy of the Indicator, and
of its convenience as a means of scientific exchange, I may
state that numerous mounted slides of minute recent and
fossil diatoms have been exchanged through the Post Office
by Judge A. S. Johnson of Albany, and myself, and that
each has found by the ordinary as well as modified forms
of the Indicator all the shells, however minute, fragmentary or
previously unknown, which the other had recorded. Some
of these objects were less than 1-1000th of an inch in dia-
meter, and yet they were found without difficulty by means of
the Indicator.

To determine whether different impressions of the Indicator
when made on the same kind of paper were comparable, a set
of objects was registered successively by seven different im-

62 ON A UNIVERSAL INDICATOR FOR MICROSCOPES.

pressions made on enamelled cards, some of which were
arranged with the ordinary paper centre-piece, and others with
the central guide-lines ruled upon glass. The numbers being
recorded for the objects when well centred upon one of these
Indicators, the slide was then transferred to each of the other
Indicators, and each object being brought into the field by its
recorded numbers, the position was carefully adjusted so that
the object should be well centered, and a record for each copy
of the Indicator was thus made. On comparing the different
numbers it was found that the coincidence was almost perfect,
the difference never exceeding one-fourth of one of the divisions
of the Indicator, an amount which might be quadrupled before
an object would be thrown out of the field of view of my
3-inch objective.

The Indicator having been put to so many and such severe
tests, I feel no hesitation in recommending it as a means of
scientific intercourse among observers, and as a means by
which collections of microscopic objects may be registered,
arranged, and catalogued ; and an index to the whole so made
that any particular specimen may be found at will either by
the original observer or any one into whose hands the slides
and accompanying register may at any time come.

The copy of the Indicator which accompanies this paper is
not given for use with the microscope, as the kind of paper
upon which it is printed is different from that used for the
standard Indicator, and therefore in consequence of unequal
shrinkage a slight deviation is produced. The Indicator for
use with the microscope is printed upon enamelled cards, and
the different impressions have been found to agree so closely
with each other as well as with the original plate that no
appreciable error is perceived.

I cannot close this paper without expressing my warm thanks
to Judge A. S. Johnson, of the New York Court of Appeals,
for his cordial sympathy and aid in testing the merits of the
Indicator, and for some excellent suggestions as to its best
form for general use. I should also express my obligations to
the engraver, J. E. Gavit, Esq., of Albany, who has spared
no pains in making the steel plate from which the Indicator is
printed as accurate as possible.

C687!)

TRANSLATIONS.

On the IMpreGNATION and GrRMINATION of ALG#. By M.
PrinesnEIm. (Abridged from the Reports of the Berlin
Academy.)

Tue existence of sexuality in the vegetable kingdom, though at
first surmised simply upon a presumed analogy in this respect
between animals and plants, and long a disputed point in
science, has for some time been admitted as an indisputable
fact. In the Phanerogamia especially, the necessity of the
conjunction of the pollen tube and the ovule for the produc-
tion of the embryo can no longer be denied by any one.
- Observations and experiments whose results admit of no dis-
pute, have established this fact, although opinions may vary
as to the essential nature of the act of impregnation.

The sexual organs of the higher Cryptogamia also are
known ; but with respect to the mode in which the respective
organs participate materially in the act of impregnation, and
even as regards the necessity of their co-operation, we possess
at present little more than vague surmises,

In the Floridee, Fucoidee, Lichens, and Fungi, older and
more recent researches have, at most, merely indicated the
existence of organs to which sexual functions may possibly
be assigned.

The latest endeavours, lastly, to demonstrate the existence of
antheridia in the fresh-water Alga, with the exception of
certain fortunate indications, to which I shall return, may be
said to have wholly failed.

This condition, however, of our knowledge, with respect to
the sexuality of plants, cannot be regarded as very encou-
raging. For, admitting that, in order to prove the existence
of sexuality it is not sufficient to show the presence of dif-
ferent organs, to which sexual functions may by possibility
belong, but also to demonstrate the co-operation of these
organs in the formation of the seed or of the young plant ; it
is obvious that the sexuality of plants, even in that division
of the vegetable kingdom in which the organs to which the
sexual function has been assigned are already known, has
not been demonstrated with that degree of certainty which
admits of no doubts being entertained. The grounds upon
which the existence of sexual relations in the Cryptogamia,
has been assumed, properly reside only in the analogy between

64 PRINGSHEIM, ON THE IMPREGNATION

the bodies contained in the antheridia and the spermatic
filaments in animals; and again, in a few isolated observa-
tions on the sterility of female Mosses and Rhizocarpee in the
absence of the male plants or organs; and lastly, in the
occurrence of hybrid forms among Ferns. All these phe-
nomena, allow the true nature of the antheridia to be assumed
with great probability, but they are insufficient to afford a
scientific proof of it.

What has been wanting for a clear and convincing proof is
the demonstration of at least a single instance, in which the
entrance of the vegetable spermatozoids into the female organ,
and their influence thereupon may be seen with perfect dis-
tinctness and in a way readily at the command of any observer.
This requirement, however, is not fulfilled by our observations
with respect to the process in the sexual organs in either the
higher or the lower cryptogams.

I do not deny the value of Thuret’s researches, which show,
in the way of experiment, the sexuality of the Fucacee ; but
in morphological processes, direct visual observation of the
process is necessarily of greater value than experiments which
always leave room for some degree of doubt. Besides this,
Thuret has merely stated the results of his experiments, and
has not communicated the precise conditions under which
they were instituted. Experimental researches of this kind,
may, it is true, show the necessary existence of two kinds of
organs for the formation of the young plant, but they throw
no light upon the essential nature of the act of fertilization.

I am equally disposed to recognize the value of Suminski’s
statements, who says that he has witnessed the entrance of
the spermatozoids into the archegonium of Ferns, in Pteris
serrulata ; as well as the importance of Hofmeister’s obser-
vation, who has noticed the same thing in Aspidium filiz
mas. But in both these instances the tissue surrounding the
archegonium opposes such difficulties to precise observation,
and the phenomenon is so little under the control of the
inquirer, that the witnessing of this occurrence can only be
regarded as a rare piece of good fortune in an individual
observer. Such instances are, certainly, wholly unfitted to
constitute the basis of a general scientific conviction; leaving
altogether out of question, the circumstance that Suminski’s
observations have received much contradiction, and that, in
any case, he has been deceived as to the part played by the
spermatic filaments in the archegonium.

It must, therefore, be regarded as a particularly fortunate
circumstance, that I have succeeded in witnessing the process
in a plant, in which it was possible to observe the penetration

AND GERMINATION OF ALG. 65

of the spermatozoids into the female organ, with the utmost
distinctness and clearness, even into the minutest details of the
proceeding ; in a plant, in fact, so happily organized that the
fertilizing organs may be directly observed without injury
to it in its natural condition; and in which, lastly, the
female organ, owing to its transparency, offers such a slight
obstacle to observation that the motion of the spermatozoids,
within it, may be closely watched for hours together, so long
as it lasts. [I have noticed the gradual completion of both
sexual organs so far, as to be enabled to describe the con-
ditions presented in them, which immediately precede the
commencement of the act of impregnation. These circum-
stances place the phenomenon so much under the control of
the observer, that he is able previously to determine the time
of the commencement of the phenomenon, and in a condition
readily to demonstrate the whole act of impregnation before
others. Lastly, since I have made these observations in
Vaucheria sessilis, one of the lowest of the fresh-water Alga,
it would appear that the process of impregnation is at
present more precisely known in one of the lowest divisions
of the vegetable kingdom, than it is in any of the other
higher plants, or in any animal; nor does it, furthermore,
scarcely admit of doubt, that sex is a universal property of all
organisms, manifesting a wonderful analogy in the most highly
organized animals, as well as in the simplest cellular plants.

1. The Vaucheria, besides the asexual multiplication by
zoospores, also exhibits a true sexual propagation, effected by
means of the two organs, known as the hornlets (Hérnchen)
and spores. Even Vaucher, who first noticed these organs,
entertained a suspicion with respect to the nature of the
* hornlets,” which he declared to be the anthers of the plant,
stating that the fertilizing pollen, which, as he thought, filled
the entire tube, was discharged through them. With his
means of observation he could scarcely have penetrated more
deeply into the nature of the process, and it is highly to his
credit that he should have advanced so far towards an expla-
nation of it.

This view of Vaucher’s with respect to the true nature of
the “ hornlets,” is far nearer the truth than are the assertions
of later algologists of the occurrence of a copulation of the
*‘ hornlet,” and the contiguous spore, an assertion which is
at once contradicted by attentive consideration of the relative
positions of the mouth of the spore and of the “ hornlet”
before and after impregnation. ‘The notion arose from a sup-
posed analogy between the phenomena of fructification in the
Vaucheri@ and the formation of the spores in the Spirogyre.

VOL. IV. F

66 PRINGSHEIM, ON THE IMPREGNATION

This opinion, however, as well as Karsten’s recent unfor-
tunate exposition of the processes said to take place in the
‘“‘ hornlets” and spore-fruit of Vaneheria will be found to be
untenable from the following description of the act of fruc-
tification in that plant.

But the true process of impregnation in Vaucheria and the
development of both kinds of sexual organs—the “ hornlet”
and the contiguous stunted organ, which is more correctly
termed “ spore-fruit,” [sporangium| than ‘ spore,’ takes
place in the following manner. Both organs arise like
papillary branches from the tube, and in close proximity; and
it is usually the case that the papilla destined to become the
‘“‘ hornlet,” is formed sooner than that in which the spore ori-
ginates (Plate III. fig.1). The two papille even from the first
differ so widely in dimensions, that they can scarcely be con-
founded, The papilla which becomes the “ hornlet,” soon
elongates into a short, cylindrical, slender branch, which, at
first, rises perpendicularly from the tube, then curves down-
wards until it comes in contact with the tube, often forming
a second or a third curve, and in this way always represents a
more or less stunted branch which frequently exhibits several
spiral turns. The papilla of the neighbouring “ sporangium,”
usually begins to appear at the time when the “ hornlet” is
commencing its first turn; but the period at which it arises
is very indeterminate, for it sometimes appears much earlier
whilst the “hornlet” is still perfectly straight, sometimes
much later after it has curved, soas to form two limbs of equal
length.

The papilla destined to become the sporangium, gradually
enlarges into a considerable sized, lateral out-growth of the
tube, far exceeding the hornlet in width, whilst in length it
is barely equal to the straight limb of the latter (fig. 2). This
out-growth, which is at first symmetrical, ultimately throws out
a beak-like prolongation on the side looking towards the horn-
let,—the “ rostrate appendage,” (rostrum) of the sporangium,
whence the latter acquires its peculiar form, resembling that
of a half-developed vegetable ovule (fig. 3). Up to this period
the hornlet as well as the sporangiwa are not shut off from
the tube from which they spring by any septum; the cavity
of the hornlet and that of the sporangium consequently remain
uninterruptedly continuous with the parent tube, and are
filled with similar contents. A great number of elongated
chlorophyll granules lodged in an albuminous plasma—never, in
this case, starch—and rounded, larger or smaller oil globules,
constitute a dense, internal lining in the tube, the sporangium,
and the hornlet. Between this granular, parietal investment

AND GERMINATION OF ALG. 67

and the true thick cellulose membrane, is a very thin layer of
colourless substance which I have elsewhere described as the
** cutaneous layer” (Hautschicht) of the cell-contents.* The
sporangium is also especially characterized by the circum-
stance that a considerable number of oil-drops accumulate in
it and apparently occupy the whole of its proper cavity.

At this stage of development, a septum is suddenly formed
at the base of the sporangium, which is henceforth an inde-
pendent cell, completely separated from the parent tube
(fig. 4). Even before the sporangium has become separated
from the parent tube by the septum, there may be noticed in
the rostrate elongation directed towards the ‘ hornlet,” the
gradual accumulation of a colourless fine granular substance,
of the same nature as that with which the wall of the parent
tube and of the sporangium is lined on the inner surface, and
which, as I have already stated, has been termed by me the
cutaneous layer. This accumulation of the ‘‘ cutaneous layer”
in the fore part of the rostrate process is continued after the
formation of the septum between the sporangium and tube,
and in consequence of its continued increase the remaining con-
tents of the sporangium, the oil-drops, chlorophyll, and plasma
are by degrees pushed towards the back and base of the
sporangium (fig. 4). Whilst these phenomena are being ma-
nifested in the sporangium, the “ hornlet’’ also undergoes very
remarkable changes. In its apex, which, so long as the hornlet
continues to grow, presents the same condone’ as the summits
of the growing branches of Vaucheria, the contents, owing
to the disappearance of the chlorophyll, have become almost
completely colourless, except that occasionally a few chloro-
phyll granules remain; sometimes more sometimes less.
Thus the point of the “hornlet,” like that of the sporangium,
appears at this time to be filled with a colourless substance,
but which is not constituted by an accumulation of the
*‘ cutaneous layer” at this point, but manifestly arises from a
molecular change associated with an alteration of form and
colour in the contents previously existing at the apex. This
difference in the mode of formation of the colourless substance,
occupying the apices of the horn and of the sporangium,
should be carefully borne in mind; it is very essentially con-
nected with the different morphological destination of the
two substances. So soon as the contents of the point of the
** hornlet” have become colourless in the mode just described,
they appear to be constituted of a very fine-grained granulose

* A notice of the Author’s ‘ Researches on the Structure and Formation
of the Vegetable Cell,’ will appear in the next Number of the ‘ Quarterly
Journal of Microscopical Science.’

F 2

68 PRINGSHEIM, ON THE IMPREGNATION

mucous substance, of whose constitution, however, no clear
insight can be obtained. Now, so soon as the transformation
of the contents has taken place, the apex of the hornlet, so
far as it is colourless, is suddenly parted from the lower,
green portion by a septum, and is thus transformed into an
independent cell, haying no communication with the parent
tube, and the basal part of the hornlet. In this case the
septum is not formed as in the sporangium, at the base of
the process, but in the middle. But the point at which the
septum is formed, in the “ hornlet,” is not very determinate ;
the portion thus cut off from the rest being sometimes larger
sometimes smaller.

After the formation of the septum in the “hornlet,” the
colourless mucus in its apex gradually assumes a more deter-
minate form, and at this time a large number of minute,
perfectly colourless, rod-like bodies may be readily perceived
crowded together irregularly, and which being still here and
there surrounded by the amorphous mucus are, as it were,
imbedded in it. Close observation also will disclose an in-
distinct movement exhibited even thus early by some of
the little rods, and from which their destination may be
anticipated.

This perfecting of the “ hornlet” coincides in time with
that stage of development of the sporangium, at which the
accumulation of the ‘ cutaneous layer” in the anterior part of
the rostrate process has attained to its greatest extent; and
this condition of the sporangium and of the hornlet immediately
precedes the act of impregnation.

This is effected in the following manner: the pressure
within the sporangium upon its walls, and especially in the
direction of the rostrum, becomes greater and greater in con-
sequence of the continued increase of the “‘ cutaneous layer”
in the forepart of the rostrum, until ultimately the membrane
is ruptured exactly at the point of the rostrum, and allows a
portion of the ‘cutaneous layer” to escape (fig. 6). The de-
tachment of the extruded portion is attended with all the
appearances which accompany the slow separation of a mucous
substance into two portions, and which in the present case
show in the clearest manner the non-existence of any mem-
brane around the escaped portion of contents. This portion
then assumes the character of a drop of mucus, which remains
lying near the opening of the sporangium, and without under-
going any organization perishes, after exhibiting the various

henomena due to the absorption of water and disintegration
(figs. 7 and 8). The accumulation of the “ cutaneous layer”
in the interior of the sporangium, in the anterior part of the

AND GERMINATION OF ALG. 69

rostrum, and the escape of a portion of it, are merely the
mechanism by which the opening is produced in the sporan-
gium destined for the admission of the spermatozoids. Im-
mediately after the formation of the opening in the sporangium,
and in remarkable coincidence with the escape of the “ cuta-
neous layer” through the rostrum, the “ hornlet” opens at the
apex and pours out its contents (fig. 5). Innumerable, exces-
sively minute, rod-like corpuscles, most of them already nearly
isolated, though many at the moment of the opening of the
“ hornlet” still imbedded in the mucus, escape at once
though the orifice. Those already isolated exhibit an
extraordinarily rapid movement in all directions, and those
imbedded in the mucus do not become detached till after-
wards, when they follow the others with equal rapidity. The
field of view is soon covered with mobile corpuscles. In great
number (20, 30, or more) they enter the neighbouring orifice
of the sporangium, which they fill almost entirely (fig. 9),
penetrating through the portion of the cutaneous layer re-
maining in the sporangium, which, though obviously without
any definite membranous boundary, owing to its viscous,
mucous consistence, offers a solid resistance to their further
penetration into the sporangium. The corpuscles continue
thus to struggle forwards into the “cutaneous layer” for
more than half an hour; bounding against its outer surface
they retreat, again push forwards, again retreat, and so on
in an uninterrupted succession of assaults and retreats—
wonderful spectacle for the observer! After this commotion
has lasted some time an abrupt boundary-line suddenly ap-
pears in the outer aspect of the “ cutaneous layer” (fig. 10),
the first indication of a tunic forming around the contents of
the sporangium, which were before bare. From this moment
the mobile corpuscles are separated from the “ cutaneous
layer’ by a membrane which effectually prevents their further
action upon the contents. They continue, it is true, to move,
to and fro, and in the roseate process, and this motion often
lasts for hours together, but at last they perish in the rostrum
itself, their motion becoming gradually slower and slower and
finally ceasing. Even after the lapse of several hours, and
when the act of impregnation has long been performed, the
quiescent, dead corpuscles may be seen in the rostrum, lying
on the front of the spore in the interior of the sporangium,
until at last they are completely dissolved and all vestige of
them disappears. The portion of the “ cutaneous layer,” re-
maining in front of the green contents of the sporangium,
constitutes a thick stratum of a colourless and transparent
substance immediately within the orifice in the sporangium,

70 PRINGSHEIM, ON THE IMPREGNATION

and consequently the penetration of the mobile corpuscles, the
spermatozoids of the Vaucheria, into the opening, and their
continued efforts, as it were, to force themselves into the
‘‘ cutaneous layer,” may be observed with the utmost distinct-
ness and precision. In several instances also, after the sper-
matozoids had already been for some time within the sporan-
gium, I have very distinctly noticed the sudden appearance of
a larger, colourless corpuscle at the extreme border of, but yet
within, the cutaneous layer (fig. 10), and of which previously
not a vestige was perceptible. Its sudden appearance after
the impregnation, its superficial position in the ‘‘ cutaneous
layer,”’ its consistence and aspect, allow scarcely any doubt to
be entertained that this corpuscle arises from one of the sper-
matozoids. I shall subsequently describe a nearly similar
thing attending the act of impregnation in the Fucacee, and
will here merely advert to the remarkable circumstance that
the act of impregnation does not take place between a per-
fectly-formed cell and one or more spermatozoids ; but that
the action of the spermatozoids is exerted upon the, as yet,
unorganized contents of the sporangium, which do not become
a cell surrounded with a membrane until after the act of im-
pregnation has taken place—the true embryonic cell of the
plant.

With respect to the structure of the spermatozoids of Vau-
cheria, I shall here merely remark that when in the mobile
condition they present the appearance of elongated slender
rods about 1-180’” in size; when killed by means of iodine,
whilst in this state, I have never been able to perceive any
further structure in them. Whilst those spermatozoids which
have ultimately ceased to move after long-continued strug-
gling, but without having entered the opening of the spyoran-
gium, appear, very distinctly, like minute clear vesicles, also
about 1-180’” in size, exhibit a distinct opaque, not brown
point, and, as I have seen with the utmost clearness, two cilia
of unequal length. Their movement is obviously more like
that of the corpuscles of which the contents of the antheridia
in Fucus are composed, than that of zoospores.

I have stated that the portion of the cutaneous layer left
in the sporangium after its bursting, and after the entrance of
the spermatozoids, together with the remaining contents of the
sporangium, are surrounded with a membrane, and become a
cell which completely fills the sporangium—the embryonic
cell of the plant.

The formation of this membrane of the embryonic cell of
Vaucheria is one of the most convincing instances in favour
of my views respecting the origin of the cell-wall, in an im-

AND GERMINATION OF ALG. 71

mediate transformation of the “cutaneous layer” (of the
so-termed “ primordial utricle’’), The separation of a por-
tion of the “ cutaneous layer,” as above described, renders it
certain that, at the time when the rostrum of the sporangium
is ruptured, the contents of the latter are not surrounded by any
proper membrane: but it is also obvious that the cutaneous
layer, which after the escape of a portion of it through the
opening still surrounds the green contents of the sporangium,
and is accumulated in a particularly thick stratum over that
part of the contents which correspond with the opening,
diminishes considerably in thickness when the formation of
the membrane ensuing upon the impregnation takes place ;
and this diminution in thickness goes on in proportion as the
membrane in question increases in thickness (figs. 10, 11, 12,
13). In this case the transformation of the cutaneous layer
into the membrane may almost be witnessed. This membrane
gradually increases to a considerable thickness; at a later
period it appears to be formed of numerous thin lamine, and
it applies itself to all parts of the open tunic of the sporan-
gium (fig. 14). After the completion of the coat of the true
spore, scarcely a trace of the previously well-developed cuta-
neous layer remains ; an excessively thin parietal lining con-
stituted of it alone remaining. The green contents, which
had been forced back by the accumulation of the cutaneous
layer, in the mean while again spread themselves uniformly
throughout the perfect spore, and form as in all cells a thick,
internal parietal coating.

The true spore thus formed by the impregnation represents,
consequently, a large cell occupying the whole of the sporan-
gium, whose membrane, formed probably zn consequence of and
certainly after the impregnation, appears to be laminated.
It is surrounded on all sides by the persistent tunic of the
sporangium, which is open in front and prolonged into the
rostrum.

In this condition the spore remains for some time longer,
without being thrown off from the parent tube on which it
was produced: but the colour of its contents, which was at
first green, gradually becomes paler and paler; the spore is
at last rendered quite colourless, and presents in its interior
only one or more largish dark-brown bodies (fig. 14, 16).
When it has lost all its colour it is detached from the parent
tube, in consequence of the decay of the membrane of the
sporangium enclosing it (fig. 17). After some time (in my
experiments, after about three months) the spore, which is
readily recognizable by the red-brown nuclei in its interior,
suddenly resumes its green colour (fig. 18), and immediately

72 MULLER, ON SPHAXROZOUM

thereupon grows into a young Vaucheria, exactly resembling
the parent plant (fig. 19, 20). Close observation shows that
the innermost layer, elongating, breaks through the thick
outer membrane, and becomes the young tube, exactly in the
same way as I have described the process of development in
the germinating spore of Spirogyra.

The observation of the germination of this spore, however,
completes the proof that the cell produced in consequence of
the action of the spermatozoids is the true propagative cell of
Vaucheria arising from a sexual act.

(To be continued.)

On Spu#rozoum, Meyen. (Tuatassicotta, Huxley.) Nocri-
Luca, and the Potycystine. By Prof. Miitter. (‘ Report
of Berlin Academy,’ April 19, 1855.)

In the ‘Annals of Nat. Hist.’ 2 ser., vol. 8, p. 433, Mr.
Huxley describes what he regarded as a new genus of
zoophytes, under the name of Thalassicolla. 'This produc-
tion, whether animal or vegetable, is found in transparent,
colourless, gelatinous masses of very various forms and size ;
showing no evidence of contractility nor any power of loco-
motion.

Of such bodies Mr. Huxley notices two very distinct
kinds—the one, consisting of oval or constricted, and many
spherical masses, is distinguished to the naked eye by pos-
sessing numerous darker dots scattered about in its substance ;
whilst the other is always spherical, has no dots, but presents
a very dark, blackish centre, the periphery being more or less
clear.

For the former kind Mr, Huxley adopted the provisional
name of TJ. punctata, and for the latter that of JZ. nucleata,
but without prejudging the question as to the existence of
specific distinctions.

These creatures, which are described as consisting funda-
mentally of a mass of cells united by jelly, “like an animal
Palmella,” are placed by Mr. Huxley with the Protozoa, and
regarded by him as belonging to the same great division as
the Sponges, Foraminifera, Infusorie, and Gregarinida,—
unicellular animals. Of the two species, TJ. punctata and
T. nucleata, the former appears to present several varieties,
and the latter seems to approach very closely in its nature to
Noctiluca.

In the Reports of the Berlin Academy for April 19, 1855,
is a paper by Prof. Miller upon Spherozoum and Thalassi-

aa

AND THALASSICOLLA. 73

colla. The former name was applied, in 1834, by Meyen to
‘a form of agastric animal, which he describes as a spherical,
muco-gelatinous mass, constituted internally of globules, which
again consist of vesicles. This genus, although Meyen’s
description is not quite accurate, would clearly appear from
his figure, according to Prof. Miiller, to be identical with the
Thalassicolla of Huxley.

Prof. Miiller then proceeds to describe and discuss the
structure and varieties of the different forms assembled by
common characters under this generic group, and fully con-
firms in every particular the description given by Mr. Huxley.
But he is disposed to subdivide the Thalassicolla of that
observer into two sub-genera, and adds an account of other
specific forms. One subdivision of the group, for which he
would retain the term Spherozoum, Meyen, on account of its
priority, would include Spherozoum (Thalassicolla) fuscum,
Meyen, and S. ( 7.) punctata, Huxley, and a minute descrip-
tion of their structure is given.

A second form, noticed by Mr. Huxley as a variety of
T. punctata, and characterized by its containing in the centre
a prismatic crystal, or crystals, and having a fenestrated
shell not unlike that of a Polycystina, Ehr., he erects into the
type of a distinct genus or sub-genus with the name of Collo-
sphera, assigning to it the specific designation of C. Huzleyt.

In his description of the structure, which corresponds fully
with that of Mr. Huxley, he lays particular stress upon the
nature of the crystals contained in the large cells. These are
sometimes present in small, sometimes in considerable num-
ber, and in one case he counted twenty-seven in a single cell.
They are about 1-60" in length, clear and colourless, and
from their form, together with their insolubility, of a nature
altogether unusual in organized bodies. They are rhombic
prisms, belonging to the two-and-two-membered system, with
four-sided summits and a greater or less truncation of the
acute, long angle of the prism. Upon measurement of the
angles, which from the size of the crystals was not very
easily taken, it appeared that the crystalline form agreed in
a very remarkable manner with that of the sulphates of
strontian and of barytes. Their chemical properties, also,
which are described, would indicate that they were composed
of a difficultly soluble earthy sulphate, which, however,
could not be that of lime. And although strontian and barytes
have not been observed in sea-water, the presence of the latter
earth therein may be surmised from the circumstance that
celestine is met with in the fossiliferous marine deposits, in
the muschelkalk, lias, cretaceous and tertiary formations.

74 MULLER, ON SPHROZOUM

The author then discusses the question of the relationship
of the Collosphera with Ehrenberg’s Polycystina, with the
shells of which that of the former exhibits a striking resem-
blance, and especially with that of Cenosphera Plutonis, Ebr.

Mr. Huxley’s second species, T. nucleata, he conceives,
requires much consideration before its true place can be
assigned. But for the present he regards it as advisable to
separate TZ’. nucleata with the Physematia of Meyen from the
gelatinous bodies with silicious skeletons, and leave the
question of their true nature open. With reference, how-
ever, to the points of analogy indicated by Huxley between
his ZT. nucleata and Noctiluca, especially in the fact of the
motion of the granules in the interior, Prof. Miiller takes
the opportunity of noticing certain luminous bodies having
the appearance of an. encysted Noctiluca miliaris. ‘These
encysted bodies,” he says, ‘‘ constituted the principal luminous
animalcules observed at Messina in the autumn of 1853.”
Free Noctiluce, at that season were not seen there; and in
1849 the same kind of encysted bodies were very common at
Nice. The cyst is a perfectly transparent, spherical capsule,
with a light-bluish brilliancy at the edge, and appearing
like the egg-membrane of some crustacea. Within this cyst
is lodged a body in all respects resembling the Woctiluca
miliaris, except that at this time no vibratile filament can be
perceived. The Noctiluca-like creature fills the cyst more or
less entirely, though occasionally it is much smaller. In this
condition the animalcules are luminous without being agitated.
When the cysts are examined under the microscope in a
small quantity of sea-water, in such a way that during the
observation the saline contents are notably increased in conse-
quence of the evaporation, a moment speedily arrives when
the Noctiluca-like body suddenly contracts itself within its
case into a little nodule, that is to say, it contracts upon the
yellowish, granular nucleus from which the filamentary strings
of the interior proceed. I have noticed this vital phenomenon,
not on one occasion only, but in many of the encysted animal-
cules.”

“ The size of the case is usually from 1-5 to 1-4". But
many are far smaller, even down to 1-10". Occasionally,
also, instead of a Noctiluca, cysts may be observed, containing
a yellow nucleus 1-24" in diameter, and once I noticed a
cyst 2-10" in size, containing, besides this rounded yellow
nucleus, quite isolated, an extremely minute Noctiluca-like
body. Of the free Noctiluce taken near Heligoland in the
autumn, the smallest were 1-20" and the larger 4-20"—7-20" in
diameter. The common variety of form, with a constriction

AND THALASSICOLLA. 75

of the circumference, which is noticed in free Noctiluce, and
the radiating filamentary branching strie beset with extremely
minute granules in the interior, were also characteristic of
the encysted bodies, which I should be the more indisposed to
separate from the Noctiluce, from their possessing the most
remarkable luminous power. At present we want the key to
these remarkable phenomena, as well as all knowledge of the
development and course of life of the Noctiluce.

After discussing the probable relations of Thalassicolla with
the Sponges and Polycystina—but without coming to any
positive conclusion on the subject, except, that in any case the
two forms of Thalassicolla and Collosphera must go together—
Prof. Miiller proceeds to describe a new genus, apparently
closely allied to them, under the name of Acanthometra, Miiller.
It consists of solitary, pelagic, silicious organisms, with a
gelatinous envelope to the body. ‘They are motionless micro-
scopic creatures, constructed of a radiating silicious frame-
work, the long, usually polyhedral crystals of which are
disposed symmetrically in all directions, and meet in the
centre without forming any central cavity. The needles are
disposed in several decussating planes, and meet in the centre
with their conical truncated extremities. This construction
of the centre out of the conical ends of rays is observed in an
otherwise widely different structure insoluble in acid, which
Professor Miiller has described and figured, from the intes-
tinal contents of the Comatula mediterranea, and which has
been termed by Ehrenberg Asterolampra pelagica.

The Acanthometre differ from the Thalassicolle in the
junction of their spicules in the middle, and in the circum-
stance that they are solitary, and, so far, are a distinct
formation. Like the Polycystine they do not constitute
masses, but are distinguished from them by the absence of a
fenestrated shell, as well as by the construction of their
silicious skeleton. Actiniscus and Bacteriastrium differ from
Acanthometra in the circumstance that their rays lie in a
single plane and are united to a common centre.

Of the Polycystine, Professor Miiller remarks, that species
of Haliomma, Dictyospyris, Encyrtidium, Podocyrtis are occa-
sionally brought to the surface of the sea by currents and
other movements of the water; at any rate it is certain, that,
though very rarely, they may occasionally be taken in the
drawing of a fine net, on larve of Echinoderms, fully-formed
young Echinoderms, Meduse, Crustacea, Pteropoda, larve of
Gasteropods, Conchifera, Annelids, &c., and on Infusoria ;
and the living Polycystine taken by him have been thus
picked up on pelagic objects. In the same way also an

76 QUATREFAGES, ON THE

abundance of organic bodies are procured, which have been
detached from their proper seat by the action of the sea, such
as living arborescent Vorticelle of the genus Carchesium,
and Polypes. But heavier minute bodies, as the shells of
dead Polythalamia are occasionally brought up from the
bottom of the sea. With respect to living Polycystine, he
remarks that they are not enclosed in a connected jelly, but
that he has seen excessively delicate transparent, distinct
filaments, without. branches, or joints protruded from the
fenestrated shell. These filaments are soft but straight, and it
appears as if each filament proceeded from one of the openings
in the shell. They resembled the radiating filaments of the
jelly in Acanthometra, and of certain infusoria, as Actinophrys,
but they were motionless, Within, the shell was always
more or less completely filled with a soft, dark-coloured,
usually brown substance, which had previously been observed
by Ehrenberg in Haliomma. In the Encyrtidium of Messina
the substance occupies the interior of the upper part of the
shell, or the vault, and is very regularly divided into four
lobes, containing'a few clear, round corpuscles. In Dicty-
ospyris, when crushed, there are seen in the interior of the
shells, cells with; yellowish granular contents. In a form,
probably belonging to. Haliomma or allied to it, having six
spicules disposed in two planes crossing each other at right
angles, the slimy matter in the interior of the shell contained
both cells with yellowish granular contents 1-240" in size,
as well as colourless cells and violet-coloured molecular
corpuscles,

On the DevetopmentT of the Spermatozoms in Torrea
virrea. By M.A. pe Quatreraces., (‘ Ann. d, Se. Nat.’
4me Sér. Tom. ii., p. 152.)

In a memoir on the organs of sense in the Annelids (Ann, d.
Sc. Nat., de Série, t. xiii), I designated, under the name of
Torrea vitrea, a worm remarkable for the complex nature and
the development of the eyes, and the extreme transparency of
the tissues. Owing to this favourable circumstance, as well
as to the unusual size of the spermatogenous masses, | was
enabled at once to observe in it phenomena, of which I have
spoken in a note annexed to the report of Milne Edwards on
the results of his travels in Sicily (Ann. d. Sc. Nat., 3e Série,
t. ill.), and concerning which I shall now enter more into
detail.

The spermatogenous masses floating in the fluid contained
in the general cavity of this Annelid are irregularly ovoid,

SPERMATOZOIDS IN TORREA VITREA. 77

and present themselves, as is usual, in different degrees of
development. At first they are perfectly diaphanous, smooth,
and manifestly homogeneous, without any trace of an enve-
loping membrane. The dimensions attained to by them in
this condition reach to as much as 1-16th of a millimeter in
length, and 1-23rd of a millimeter in breadth.

At this epoch they may be seen to exhibit two grooves,
crossing each other at a right angle, and whose direction
has not appeared to me to present any constant relation
with the form of the mass itself. It is probable that this first
form of division may in some sort be accidental, for I Lave
only very rarely noticed it.

The number of grooves soon increases, and they become
more marked and deeper, and the mass, after having presented
a surface subdivided into large irregular lobes, assumes a mul-
berry-like aspect, and ultimately becomes completely granu-
lous. During the time that these phenomena are being
manifested, the mass continues to increase in volume, and in
its ultimate condition it is sometimes 1-12th of a millimeter
long by nearly 1-16th of a millimeter broad.

The masses when a little further advanced soon split up,
and the tail of the spermatozoids is then apparent. The
spermatozoids continue to adhere to each other for some time
longer by their bodies, as well as to the granulations not yet
transformed ; ultimately they are gradually separated.

At the moment when the spermatozoids separate themselves
from the minute masses, of which they constitute a part, their
body is almost fusiform, and perhaps not more than 1-100th
millim, long, and 1-300th millim. thick. But they grow
during the time they remain in the midst of the fluid
which bathes them, the body and the tail elongate ; and besides
this the former increases considerably in its transverse dia-
meter. Among spermatozoids quite mature, some will have
attained to a lengthof 1-60th millim., and breadth of 1-150th
millim,

I have long since remarked the analogy presented between
the progressive breaking up of the spermatogenous masses
and that of the vitellus. Numerous observers, it is well known,
have confirmed what I have written on this subject since 1845,
but it is a point upon which | have found myself continually
at discord with some who have been specially engaged in re-
searches of this nature.

In Germany, more especially, almost every naturalist who
has spoken of the development of the spermatozoids has
applied, in this department of physiology, the cell-theory of
Schwan. The spermatogenous masses, in their eyes, have

78 HARTIG, ON DILUTE SULPHURIC ACID ON

represented the mother-cells, whilst the divisions of this mass
have been secondary, tertiary, &c., cells. Lastly, the sperma-
tozoids themselves have simply been the last generation of
cells, separating themselves almost in the manner of vegetable
spores.

When I made my observations on the Torrea, I sought
with the greatest care to discover whether there were any
envelope around the masses destined to be resolved into sper-
matozoids, and notwithstanding their unusual size in this worm
I have never been able to perceive the least trace of such a
covering. Neither have I been able to distinguish the walls
of cells during the division. Since that time I have, many
times, instituted researches of the same kind, and invariably
with the same result. The spermatogenous masses have
always appeared to me to be composed of a perfectly homo-
geneous substance, and never to present any indication of a
cell-nature.

If to these observations are joined the positive facts which I
have pointed out in the vited/us of worms and of the mollusca,
the negative results which I have just recorded acquire, as it
seems to me, a real value. ‘Thus the cell-theory had been
applied, very happily as it seemed, to the segmentation or
division of the vitellus; but this doctrine necessarily suc-
cumbed before the fact that the most marked lobes, those in
which both the nucleus and the cell could not fail to have
been the best characterized, spontaneously fuse into one
another. If, then, theoretical conceptions are discarded in
favour of observation, the views which I have just explained
will I hope be adopted ; and it will be acknowledged that in
this case at least the cell-theory should be abandoned.

On the Influence of DiturE Sutenuric Acrp on the Deposit
Layers of the CELi-watt in its earliest condition. By Dr.
T. Harrie. (Botan, Zeitung, March 30, 1855, p. 222.)

In a previous paper in the same journal the author has shown
that the continued multiplication of cells in the ligneous and
alburnum layers, is effected by a twin pair of parent-cells
belonging to each fibrous ray, the inner one of which throws
off a series of sterile secondary cells towards the medulla, and
the outer a similar series towards the bark.

Each of the parent-cells, which correspond in size, form,
and structure, consists of a thin cell-wall and a double
ptychode-sac; the cell-wall itself consists of an internal and
of an external cell-membrane, between which is deposited a

THE DEPOSIT LAYERS OF THE CELL-WALL. 79

greater or less number of astathe layers, which swell up
strongly in sulphuric acid. (Bot. Zeit. 1854, p. 51, Tab. 1,
fig. 16-17, a, b).

The youngest of the secondary cells, both of the wood and
of the alburnum, exhibit no difference; they correspond in
size, form, and structure not only with each other, but also
with the two parent-cells, with which they constitute the
compound layer designated the ‘cambium.’ The first appa-
rent distinction in the structure of the secondary cells destined
for the ligneous substance, and of those belonging to the
alburnum, is shown in the dotting—the dots in the former
being always distinct, and in the latter always grouped in a
cribriform fashion. (Bot. Zeit. 1854, Tab. 1, fig. 24).

In the part of the ray belonging to the ligneous substance
it is the cell-fibres and lamellar-fibres, and in that belonging
to the alburnum substance it is the telial-fibres which retain
unaltered the cambial condition of their walls; no further
thickening of the wall ever takes place in these cells. In the
ligneous part of the ray it is the woody fibres, and in that part
which belongs to the alburnum it is the true alburnum-fibres
which exhibit a further thickening of the cell-wall, which is
effected by the deposition of new layers on the inner side of
the cambial-wall. These layers of the second and subsequent
generations afterwards constitute by far the main part of the
thickness of the wall, whilst the cambial-wall contracts to
such an extent, that its original constitution of cell-membranes
and deposit-layers, which in the course of its development was
distinctly demonstrable, is no longer perceptible. In this con-
dition I have myself, he says, several times confounded the
cambial-wall with what, in other situations, I have correctly
described as ‘ eustathe’ (intercellular substance, but not in the
sense in which Mohl understands that term), or as ‘ cell-glue.’
Thus, for instance, in my Leben d. Pflanzenzelle, t. ii, fig.
27 e, it is not ‘ eustathe,’ but the cambial-wall, contracted by
sulphuric acid and no longer capable of expansion, that is re-
presented,

In a former memoir “ Upon the formation of the deposit
layers,” I have shown how these additional layers arise from
the regeneration of the ptychode-sac.

The additional layers of the second and subsequent genera-
tions, both in the ligneous and in the alburnum fibres, in their
youngest condition, assume a beautiful rose-red colour when
brought into contact for some hours with dilute sulphuric
acid. In the same section and under precisely similar influ-
ence of the acid the cambial-wall remains unchanged, both in
the region of the ligneous and of the alburnum-fibres, as well

80 WEDDEL, ON THE CYSTOLITES

as in the cambium and in the telienchyma, where no part of
the wall at any age is coloured by sulphuric acid, owing to
the circumstance that the entire cell-wall in these situations is
composed of the cambial substance. It may thence be justly
concluded that an original chemical difference exists between
the deposit-layers of the cambial wall and the additional layers
of the second and subsequent generations ; and that this dif-
ference is manifested at a later period in the resistance offered
by this parietal layer to the expansive influence of acids and
alkalies.

The period is but very brief, during which the additional
layers of the second and subsequent generations are reddened
by sulphuric acid. Ina shoot of Pinus austriaca examined
on the 7th June, in which the annual ring had begun to be
formed in the early part of May, only the 16-18 outermost
fibres of each ray were reddened, whilst the older, 18-20 fibres
assumed a brown colour. This gives a period of 2 or 3 weeks
as the time during which the reddening effect of sulphuric
acid is manifested.

On the Cysto.ites or CaLcArEous Concretions in the Urti-
CACEX and other Piants. By H. A. Weppet, Aide-
Naturaliste in the Jardin des Plants. (From the Annales

d. Sc. Natur. Ser. 1V., tom. ii., p. 267.)

Axout the year 1827, J. Meyen discovered in the leaves of
Ficus elastica, and of several other species belonging to the
same genus, certain pedunculate corpuscles, constituted, as
he supposed, of gum or of some analogous substance; he
ascertained that these corpuscles increased by the super-
position of new layers, and that ultimately they became covered
with notches and elevations composed of a calcareous, crystal-
line material, soluble with effervescence in acids (carbonate of
lime).

Long after this discovery by Meyen, M. Payen undertook
the study of the same bodies, whose existence he demonstrated
in a great many other plants belonging to the family of the
Urticacee, and he concluded from his researches that their
constituent material, which was regarded by Meyen as being
of a gummy nature, was in fact cellulose, and that it was dis-
posed, not in concentric groups, but in true cells united into
racemose masses, each of which ‘was destined for the secretion
of a certain quantity of carbonate of lime. This view, which
was adopted by several botanists, has been combated by others.
Thus Schleiden, who was among the first to oppose it, appears

IN THE URTICACEZ. 81

to think that the corpuscles in question are analogous to the
deposits which, in time, obstruct the cavity of certain hairs,
in the Boraginee for instance ; and which, particularly in the
common Fig, may be seen prolonged into the cavity of the
bulb of the same kind of hairs. The cells in which the cor-
puscles arise would even, according to Schleiden, be urticating
hairs, whose base only was developed. The only argument
which it is necessary to oppose to this theory, is the fact that
the bodies in question are often seen beneath the epidermis
and even in the medulla itself. Moreover, the deposit con-
tained in the hairs of the Fig are formed in quite a different
way from the gummy, calcareous, pedunculate corpuscles of
Meyen, and behave towards reagents in a very different
manner,

More recently, again, Payen’s theory has found an anta-
gonist in H. Schacht, to whom we are indebted for a very
extended memoir on the subject. I shall content myself here
with remarking, that he adds absolutely nothing essential to
what Meyen had already stated with respect to the anatomical
constitution of these corpuscles. Schacht, moreover, adopts
entirely Payen’s opinion as regards their chemical constitution,
and notices them besides as characterizing the tissue of another
large family of plants—the Acanthacee—in which their pre-
sence would seem to have been first shown by M. Gottsche of
Altona.

Lastly, I have myself for several years studied these sin-
gular corpuscles ; and the result of my observations has also
been completely in accord with that at which Meyen had
arrived. Struck with the differences, which seemed to me to
exist between these bodies developed in special cells, and all
the other mineral secretions of plants, I gave them the name
of cystolites (céioric, Moc). ‘These concretions, moreover,
play a more important part in the physiognomy of the plants
in which they occur than might at first be supposed, and are
capable of furnishing the most valuable diagnostic characters ;
it appeared a useful object, therefore, to describe them more
clearly than had hitherto been done.

Their figure is most commonly spheroidal ; but in many of
the Urticacee, and in a great number of the Acanthacee, they
assume an oblong or more or less linear form, attenuated
towards the ends, sometimes in that of a bow, or more rarely
of a horse-shoe shape. In the living plant they are visible
only on dissection or by transmitted light ; the leaves in which
they are contained then exhibit when viewed with a magnify-
ing glass, translucid lines or points, but from which it would
scarcely be possible to draw any precise diagnostic characters.

VOL, IV. G

82 WEDDEL, ON THE CYSTOLITES

But this ceases to be the case when the plant is dried. The
cystolites in fact do not contract in consequence of the desic-
cation like the rest of the tissue of the leaf or stalk, but are
in a certain sense protruded externally, and the delicate mem-
branous tissue covering them is moulded so exactly upon them
that it is difficult when viewing them in this condition, to
believe, that they were previously concealed in the thickness
of the organ. Many botanists, deceived, under these circum-
stances, by their form, which is often linear, their white colour,
and especially by the remarkable relief in which they stand,
have described them as adnate hairs, others as Malpighian
hairs, or lastly as simple tubercles. Gaudichaud was the first
to recognise their mineral nature, regarding them, however, as
true raphides, an opinion since adopted by several others, but
which cannot sustain serious examination. Nevertheless the
cystolites thus rendered visible on the exterior by the desic-
cation, furnish specific and even generic characters of great
value in so natural a family as that of the Urticacee. Among
the genera belonging to this great group, in which these little
bodies especially afford good characters, I would here parti-
cularly notice the genus Pilea, of which the species at present
known amount to more than 100; and the genus Llatostema,
which contains nearly 40. Another genus of Urticacea,
Myriocarpa, may be recognised at once, and in the absence of
the organs of fructification, by the radiated disposition of the
cystolites around the base of the hairs which clothe the upper
surface of the leaves. In all these plants the calcareous cor-
puscles are, usually, more or less fusiform or linear; whilst in
the greater part of the stinging Urticacee, in the Parietarie,
and in the Béhmeria, they are nearly always spheroidal, pre-
senting, in the dried plant, the aspect of projecting points,
which often give to the leaf a certain asperity, which would
be sought for in vain in the living plant.

In all cases when studying the development of the sphe-
roidal cystolites, I have had no difficulty in perceiving the
pedicle, although it is sometimes very slender. This tenuity,
however, of the suspensory filament is still greater in the
linear cystolites ; so great, in fact, that Schacht declares that
he has sought for it in vain. Nevertheless there is no doubt of
its existence, at any rate in the first period of the development
of the corpuscle, for if the cell be viewed from without to
within, a minute point will always be observed on its exterior,
evidently marking the insertion of the pedicle. It may happen,
moreover, that the suspensory filament is eventually com-
pletely concealed by the new layers successively added to the
body of the concretion, which then appears to be sessile upon

IN THE URTICACE. 83

the wall of the cell in which it is produced. In this case it
resembles, to a certain extent, a Malpighian hair developed
in the interior of a cell.

The size of these cystolites is extremely variable; those of
a linear or fusiform figure, nevertheless, commonly attain to
much larger dimensions than the others. In several species
of Pilea, 1 have observed some more than a millimetre in
length ; whilst, on the other hand, there are some of a sphe-
roidal form whose diameter scarcely reaches 2 to 3 1-100ths
of a millimetre.

I have often been able to demonstrate, and as it seems to
me beyond the possibility of error, the concentrically laminated
structure of the body of the cystolite ; but in no case have I
been able to perceive in the pedicle the successive layers
figured by Meyen and Schacht; it has always appeared to me
to be a perfectly homogeneous appendage of the wall of the
cell, and to arise from a circumscribed and continuous thick-
ening of it. It behaves therefore towards reagents exactly in
the same way as the substance of the wall itself, except per-
haps that iodine develops, more frequently, traces of azotized
matters, This fact did not escape the notice of Payen; and
it cannot be doubted that this matter has something to do with
the rapid development of these bodies. Perhaps the pedicle,
directed towards the centre of the cavity of the cell, may
act there like a foreign body, around which the calcareous
matter is deposited. However this may be, the concretion
and its pedicle always remain organically quite distinct.

With respect to the physiological import of the cystolites,
considered generally, it is a point not easily determined with
precision; but if their situation, and the time at which they
acquire their complete development (the fall of the leaf), and
lastly, their chemical composition be considered, they would
appear to be rather a sort of excretion, than a secretion useful
in any of the functions of the plant. In this point of view,
therefore, the cystolites may very properly be compared with
other mineral matters met with in the cells of plants, and in
particular to those which occur in the crystalline form. Link,
it is true, has compared the latter to the calculi occurring in
animals ; but the analogy between certain of these calculi and
the cystolites, appears to me much more remarkable.

( 84)

NOTES AND CORRESPONDENCE.

The Circulation in Aqueous Plants.—In the 8th number of the
Journal, published in July, 1854, there is an account of the
circulation in the Closterium lunula, by the Hon. and Rey.
Mr. Osborne, and Mr. Hogg. This circulation, according to
Mr. Hogg, is “no new discovery,” but to me, as a young
microscopist, I must confess it was so, as until I applied the
parabolic reflector of Mr. Wenham, with the assistance of
direct sunlight, [ have never suspected it to exist. By this
means of illumination, however, it appears to me to be very
distinct, although I have seen it to better advantage in C.
acerosum.

Some time in April last I met with some good specimens
of this plant, and with }-inch objective of Smith and Beck
their No. 1 eye-piece, Mr. Wenham’s reflector, and a prism
instead of mirror, with the assistance of direct sunlight, I had
repeatedly the gratification of beholding what Mr. Osborne
appropriately calls a “godlike” sight of the most beautiful,
undulating ciliary motion, magnificently illuminated with
prismatic colourings. After a longer time than usual spent
over one specimen, the water in the cage partially dried, and
on the edge of the air-bubble being brought by this means in
close proximity with the specimen, the usual effect of external
ciliary motion was most distinctly visible to myself and a
friend for some considerable time, although no cilia could be
distinguished. The rapid and continuous passage of a stream
of molecules in the direction of the extreme end showed
beyond the possibility of any doubt that cilia were there.

A few days subsequently I met with a good sample of the
Chara, and it struck me to examine the circulation by the
same illumination I had so successfully employed with Clos-
terium. Judge my delight when I found precisely the same
appearances, the same rapid undulations, together with the
same brilliant coruscations, that almost satisfied me that
herein consisted the phenomenon of circulation in aqueous plants.
I am not aware that this has before been noticed, or at any
rate recorded, and hope some more practised observers will
put it to the test; for whether I am correct in supposing the
circulation in water-plants originates in ciliary movement or
otherwise, they will be amply repaid for the trouble expended,
in the glorious sight presented to them.—JAmEs WESTERN,
Veterinary Surgeon, Madras Artillery.

MEMORANDA, 85

On the Starch Grain—In the Botan. Zeitung for June 8,
1855, p. 407, is a short notice, by O. Maschke, on the starch
grain. Adverting to a paper “On the Structure of the Starch
Granule,” by Mr. Grundy, which appeared in the ‘ Pharma-
ceutical Journal for April 1855, the writer refers to his own
researches on the subject, made in the years 1852 and 1853,
and published in the ‘ Journal fiir praktische Chemie,’ vol.
56, part 7-8, and vol. 61, part 1; and states that in these
communications he endeavoured to show :—

1, That the starch-grains are enveloped with cellulose, and
consequently that they represent vesicles or cells.

2. That the starch-grains examined by him were constituted
of several cells, arranged one with the other in a pill-
box fashion.

3. That the amylon exists between these cells in a soluble
or insoluble state, in the latter condition presenting the
form of extremely minute granules.

4. That the so-termed nuclear point of the starch-grain is
a central cavity in the innermost vesicle, which is
sometimes empty in consequence of desiccation, and
sometimes filled with fluid.

5. That the “ moss-starch” (moosstarke) is merely amylon,
modified by the action of acids (modified starch).

6. The “staleness” of bread depends upon the circumstance
that the soluble starch, which exists in new-baked
bread, passes into the insoluble condition.

7. That what is termed “leiocom” is produced simply
from the action of an acid ; and that this acid is formed
in consequence of the elevated temperature necessary
for the demonstration of this substance.”

As the author does not appear, when these observations
were made, to have been in possession of a good compound
microscope, he may perhaps, when so furnished, see reason
to change his opinion in some respects as to the structure of
the starch-grain.

Aperture of Object-glasses.— Professor Bailey having noticed
in the last Journal my remarks bearing reference to the fact
of his being able to discover the markings on the most difficult
tests known, when mounted in balsam, I beg to state, that
my observations were dictated by no other motive than the
desire of establishing a correct fact, and that I was not pre-
judiced by any favourite theory.

Professor Bailey says, “It is appparent from the above
that Mr. Wenham has convinced himself, both by reason and

86 MEMORANDA.

experiment, that I ought not to have seen the markings on
delicate test objects, when mounted in balsam.” From this
I infer that Professor Bailey had not seen a paragraph con-
tained in my communication, in the ‘ Quarterly Journal of
Microscopical Science’ for January, 1855, page 162, or I feel
assured that he would not have thought it necessary to make
this form of reply, for I therein assert that subsequent expe-
rience had induced me to recall my remarks, and that I had
lately succeeded in bringing out the striz of some very
difficult tests when in balsam. I will now corroborate this
by saying that I am convinced that Professor Bailey is per-
fectly correct in his statement with respect to balsam tests,
which must henceforth be recorded in the list of facts. Thus
far we are quite agreed; but as Professor Bailey’s allusions
extend beyond this point, self-defence will be my apology for
taking some notice of them. Referring to me, Professor Bailey
says, “‘ The error in his arguments will be sufficiently obvious
to any one, who will trace the course of a divergent pencil
of rays out of the balsam instead of into it, as in Mr. Wenham’s
experiments, and it will then be seen, that large angles of
aperture are as useful for balsam-mounted specimens as for
others.” Surely Professor Bailey cannot have well considered
this extraordinary, because extremely incorrect assertion,
which is tantamount to saying, that a diverging pencil of rays
from a luminous point, submerged in balsam, will in each
case continue their course in the same right line, without
suffering any refraction, after emerging from a plane surface
of the medium. ‘This is contrary to all reason, for in the
trigonometry of optics where there are sufficient data con-
nected with the position and direction of the rays, it comes
to precisely the same thing whether they are traced into the
refractive medium or out of it. But taking Professor Bailey
on his own statement, I will explain what is the real effect in
this case. Suppose a series of rays diverging from a balsam-
mounted object ; from the mean refraction of the balsam and
glass cover (the indices being about 1°54 and 1°53) total
reflection would take place from the upper surface of the
latter at an angle of very nearly 41° from the perpendicular.
This, therefore, at once limits the angle of rays collected by
the object-glass to 82°, and as total reflection begins where
refraction ceases, all rays beyond this point will be entirely
reflected down again into the balsam, and lost by dispersion ;
and the extreme rays of the pencil of 82° that just exceed
total reflection by passing through the glass, so far from con-
tinuing their course in a straight line, are brought down by
refraction to the very level of the top surface of the cover

MEMORANDA, 87

itself, so that if it were possible to use an objective of 180°
of aperture, the effect of balsam-mounting would reduce it at
once to 82°, and allowing for all possible variations of the
refractive powers of the balsam and cover, I have no hesita-
tion in affirming that any object mounted in the usual manner
in this medium, has never been seen with an angle greater
than 85°; but in all probability the extreme limit has been
about 78°. This statement is not the result of mere hypo-
thesis, but admits of ocular demonstration, by experiments that
will prove it at least half-a-dozen different ways, and is so
true in theory, that to endeavour to disprove it will be to
take the difficult course, of attempting to undermine the
ground upon which I have taken my stand, by denying the
first laws of refraction upon which my assertion is based.

Professor Bailey has, no doubt, experienced the advantage
of the utmost extent of aperture that can be obtained, in that
particular department of investigation, in which te has so
eminently distinguished families and 1 am willing to admit,
that if the highest powers are to be used only for viewing
thin and flat objects like the Diatomacee, the aperture may be
as near to 180° as may be practically convenient for this
especial purpose; but considering all the requirements, and
perhaps more useful applications of the object-glass, | am
still of opinion that beyond 150° there is no real advantage to
be gained. I have expended much time, and taken special
delight in the cultivation of the largest apertures, and possess
an assortment ranging up to the greatest possible limit, and
I can even now bring out striae with 150° as readily as
with anything beyond it, with the positive advantage of a
greater distance between the front lens and object. Some of
the phenomena described in my communication to the present
Journal are extremely severe tests of all the good qualities of
an object-glass, and yet I have had some, whose performance
is unrivalled upon a difficult diatomaceous test, repeatedly
break down and fail in their effective duty, when applied to
the investigation of plant-circulation, from the fact of their
possessing too much aperture.—F, H. Wenuam.

On the Structure of the frond of Polysiphonia fastigiata.— Ihe
frond of Polysiphonia fastigiata, bearing antheridia, consists of
a mass of transparent matter, in which are jrabedded coloured,
elongated cells or siphons. These are so arranged side by
side in successive rows as to surround a central hollow passing
through the whole extent of the frond. Each row of siphons
with its hyaline matrix forms a kind of ring or section of a
tube, and under pressure has a tendency to detach itself from

88 MEMORANDA.

those next to it. These rings are articulated by some inter-
vening dark matter laid transversely.

The tube thus formed is occupied by a series of clear
vesicles of the same length as the siphons, which impress
upon their outer surfaces a set of corresponding parallel
depressions, and each vesicle contains an urn-shaped body of
the same colour as the siphons. A row of spines is placed
round the shoulder of this organ, and from either end a stem
with a slightly-expanded termination passes out, by which all
the vesicles and their contents are
brought into connection. These
urn-shaped bodies when immedi-
ately below a bifurcation of the
frond are rather more squared
than the rest, and give out a com-
municating process from each of
the distal angles. ‘The chain is
in this manner continued upwards.
The contents in the conditions in
which I have seen them are mere
granular matter. The same or
corresponding structures have not
been observed in other species of
Polysiphonia ; but in the frond
of P. fastigiata, producing tetra-
spores, they are present.

No description or representa-
tion of them has yet been pub-
lished, and their functional rela-
tions remain unknown.

Polysiphonia.

A. Terminal portion of a frond of Polysiphonia fastigiata, bearing
antheridia.

B. Transparent cells containing urn-shaped bodies from interior of
frond.

C. Urn-shaped body in eell from a part of the frond immediately
below a bifurcation.

Further remarks on the Ely’s Foor.— If Mr. Tyrrell’s theory be
correct, ‘‘ That the Fly uses the hooks as levers to detach the
foot,” we should expect &@ priori that the Beetle did so: but
the contrary is the fact. I placed one (not aquatic, or of the
Curculio tribe) under the microscope, feet upwards, which
was remarkably slow in its movements, and furnished with
two circular pads, and one triangular, possessing trumpet-
shaped hairs, and having the power of secreting fluid. When
detaching the foot in walking, it raised the hooks first, and

MEMORANDA, 89

kept them suspended for an appreciable length of time, before
it raised the pads. I placed a blow-fly for examination, after
having removed, under the influence of chloroform, the flap
and two hooks of one foot, and about half the hooks of
another: it could not attach the foot with one flap efficiently ;
but the one in which the hooks were so far shortened, that
they extended only to the middle of the flaps, it used very
well. Query, Would not the flap have been torn through,
and half left on the glass, in this case, if the above theory
were correct ?

When the foot of the Midge (one of the Tipulide) is in
action, it has the appearance of a horse’s foot in miniature.
I believe the Walrus, although it sometimes exceeds a ton in
weight, has a similar apparatus to the Midge, by which it
can support itself on the almost perpendicular sides of the
immense icebergs it has to traverse.

The Midge’s foot terminates in a single sucker, and has no
hooks wherewith to detach itself.—J. Hepworrn, Croft’s
Bank.

Microscopic Preparations.—F rom a notice in the Botanische.
Zeitung for November 10, 1854, we perceive that Dr. J.
Speerschneider, of Blankenburg, near Rudolstadt, in Thuringia,
proposes, apparently with the co-operation -of Professor V.
Schlechtendal, to issue a collection of microscopical prepara-
tions, intended to exhibit the most important points with
respect to the structure and development of plants. The
entire collection will contain ten to twelve dozen preparations,
and will be issued in five to six parts, each of which will cost
only three Prussian thalers; and subscribers’ names may be
sent either to Dr. Speerschneider, as above, or to Professor
Schlechtendal, at Halle.

( 90 )

PROCEEDINGS OF SOCIETIES.

MicroscoricaL Society, May 23rd.

On a new form of Microscope. By Ropert WartneTon, Esq.

In carrying on the observations in my smal] Aquarium, which have
for some time past occupied my leisure hours, I was very anxious
to bring the microscope to my aid in examining the minute organ-
isms or delicate structures of the creatures I had the opportunity
of noticing, and which had been maintained for a considerable
period in a healthy condition; at the same time it was important to
do this without disturbing them from the natural position they had
taken up, or removing them from the water. It occurred to me
that I could best effect this object by attaching the microscope to the
edge of the table, on which the aquarium was placed, by means of
a clamp, and that by shifting this along before the front of the
tank I could range over all the objects situated at that part.

In searching among some old chemical apparatus for a clamp
likely to be suited for this purpose, I happily found one that had
been employed for carrying the plates or subjects in an electrotyping
trough, and which appeared exactly adapted for the object I had
in view, being fitted with two ears which projected from the back,
and through each of which a circular hole was drilled for carrying
a rod, one of them being supplied with a binding screw for the
purpose of adjusting it to any desired length. As this clamp fitted
well to the edges of the table, I had only to get an ordinary micro-
scope body arranged, with a cradle-joint and circular rod attached
to the back and end of the bar which usually carries the rack and
pinion of the coarse adjustment, and the desired requirements were
fulfilled. By this means several motions of the instrument were
obtained : first, the power of elevation or depression, by means of
the rod, in the front of the tank ; second, the focussing for distance
by the rack and pinion; third, angularity in the position of the
body by the cradle-joint ; fourth, the traversing motion along the
margin of the table, and also a curvilinear motion of the instrument
by the rotation of the circular rod in the back of the clamp.

This object having been completed to my satisfaction, it next
became a question whether the instrument, with a few additions,
could not be turned to more general utility as a travelling micro-
scope, particularly for use at the sea-side. To effect this I procured
a small flat block of wood having an upright piece fashioned at
right angles across its upper surface, on the edge of which the
clamp or saddle could be screwed, and the body of the instrument,
being adjusted at right angles to the rod, thus brought to act over
any vessel, as a saucer or plate, containing the object to be
examined ; the length of the rod being the limit of the distance
over which it would range. This arrangement rendered the instru-
ment doubly useful, and was found to realize all my anticipations.

PROCEEDINGS OF SOCIETIES. 9L

The next step in its further development arose from the observa-
tion, that, when the wooden block was set upright, on the angle
formed by the strut, or projecting ridge, and the bed, it inclined
nearly at the angle, or diagonal direction, in which the microscope
is usually employed, and that by shortening the block slightly on
one side of the ridge the most comfortable position for observation
could be readily secured; the clamp or saddle carrying the body
being then attached over the upper extremity of the block. It
therefore merely required a stage and mirror to render the instru-
ment serviceable in this new form. This was effected, keeping the
portability of the result always in mind, by inserting into the
under surface of the block, at a proper distance, a dovetailed
socket for the reception of an elongation, or tongue, of a moveable
stage-plate, and below this a small ferrule was introduced for carry-
ing the rod of the mirror.

It was also found that, by elongating the rod, and craning the
body of the instrument over into a vertical position, it might be
employed as a dissecting microscope; the only addition that was
required being the insertion of another dovetailed socket into the
block to carry the stage-plate in a horizontal position, With these
various adaptations to the circumstances as they presented them-
selves, the little instrument assumed its perfect form.

As this original microscope was of inconvenient size and weight,
and as there was no apparent reason why these objections could not
be easily obviated, I determined to have a new one made, maintain-
ing the same form and construction, but reducing the weight and
dimensions wherever it was practicable; the result has been the
small instrument which was submitted to the Members of the
Society on Wednesday last, and which I shall now proceed to
describe in detail.

The block, or bed, is made of oak, or other heavy wood, of about
half an inch in thickness, and is 7} inches long by 3 inches wide.
Into this are countersunk the two brass dovetailed sockets, the
diagonal one, or that which carries the stage plate in a diagonal
position, and at right angles to the bed, at 33 inches from the upper
edge, the horizontal one at 3 inches; the circular socket for receiv-
ing the rod of the mirror being inserted about 14 inch from the
lower edge. At the back of the block are introduced two circular
ferrules, 3} inches from the top, for the reception of two strong
pivs, which connect the strut, or upright piece, with the bed ; this
arrangement enables us to remove this from its position, and to
pack the whole in a much smaller compass. In the side of the bed
is also inserted another ferrule to receive the pin of a condensing
Jens for concentrating the light on the stage for opaque objects, or
for the same purpose between the source of light and the mirror,
it is placed 23 inches from the top.

The strut, or upright piece, is of the same width and thickness
as the bed, and 34 inches in heighth, having two strong pins inserted
for connection with the main piece.

The stage is a single stout plate of brass, of the same width as

92 PROCEEDINGS OF SOCIETIES.

the bed, and 34 inches deep, bevelled at its sides, and having a short
tongue, or elongation, at the lower edge, for insertion into either
of the dovetailed sockets; it has a large central aperture, and is
provided with a light cross-piece, fitting on the bevelled sides of
the stage, and capable of moving easily up or down, for carrying
the object-slides ; at the right-hand corner of the stage there is also
a small aperture, with a saw cut through its edge, for the reception
of the pin of a pair of forceps. The small condenser may also be
inserted below the stage into this aperture, so as to condense the
rays from the source of light to the mirror, or between the mirror
and the stage.

The clamp, or saddle, should be made as small and as light as
is compatible with the thickness of the wooden bed, or stand, and
the weight which the screws have to maintain firm and steady.
The body is constructed of two tubes sliding the one within the
other, so as to allow of its elongation to its proper length when in
use. The outer one of these is embraced by a short tube two inches
long, lined with cloth, and through which the body tube should
have a steady and easy motion, as that forms the coarse adjustment.
To the lower edge of this tubular support is soldered the cradle-
joint with its attached rod ; the latter being five inches in length.
The fine adjustment, which I believe is new, is situated just above
the object-glass ; it is constructed on the principle of a common
union-joint, the outer half of which works in a male screw at the
extremity of the body-tube, and acts
against a spring in order to maintain a
constant bearing, thus :—A is the lower
part of the body-tube, having a ring of
metal as a stop in its interior, at 1,
against which the spring, 3, bears, and
having a screw on its exterior, at the
lower aperture, for the half-union, C,
to work in. JB is the tube which re-
ceives the object-glass at its lower
aperture, and has a ring of metal at-
tached to its upper extremity, within
the body-tube, at a, for the bearing of
the lower coil of the spring, 3; it has
also a slight projection on its exterior,
near the object-glass, which is embraced
by the curved extremity of the half-union, C.

The great object in this arrangement was to avoid the projection
of a screw-head, which in packing away the instrument generally
takes up so much space. By these modifications the whole instru-
ment, together with a live-box, two object-glasses, the condensing
lens, and the forceps, enclosed in a leather case, occupies a space
of 8 inches long, by 3 wide and 3 deep; so that it can be easily
carried in the coat-pocket. ‘The cost is estimated at about £3 for
the microscope complete, including the packing-case, without the
powers ; or with two French achromatics, at 15s. additional.

( 98)

ZOOPHYTOLOGY.

In Johnston’s ‘ History of British Zoophytes,’ six genera of
Vesiculariadan Polyzoa are described, but of which one,
Beania, is more properly referrible to the cheilostomatous
sub-order. To these have subsequently been added two or
three others ; as Avenella, by Sir J. Dalzell, MWimosella by the
Rey. T. Hincks, and, more recently, a form described under
the name JVolella, by Mr. Gosse. To this number we have
now to add another generic form, new to the British Fauna,
and a new species belonging apparently to the established
genus Farrella, although the characters of that genus, as
assigned to it by Van Beneden, will require some modification
for its admission.
Order. PoLYZOA INFUNDIBULATA.
Sub-order III. Crenostomata (VESICULARINA).
Fam. 1, VESsICULARIADZ.
§ 2. Polypides without a gizzard.
Gen. 1. Farrella, Ehrenberg.
Lagenella, Farre.
Laguncula, Van Beneden.

Char. Cells oblong or tubulous, scattered, arising from a creeping sto-

toniferous tube.
Farrella gigantea, Busk (n. sp.). Pl. V., figs. 1, 2.
Cells tubulous, sessile, not contracted at the base; tentacles numerous

(18—20). Ectocyst flocculent, rendered opaque by imbedded earthy
matter.

Hab. Tenby.

This very distinct form is characterized, in the first place,
by the comparatively enormous length of the cells, which
occasionally exceed 1-10th of an inch in length; and secondly,
by the peculiar constitution of the wall or ectocyst. This is
not horny and transparent, as in most of the other Vesiculari-
dans, but appears to be of a soft, flocculent texture, in which
is imbedded, as it were, an abundance of earthy matter,
apparently derived from the mud in the water in which the
creature lives, and consequently composed for the most part
of argillaceous and silicious particles. A similar constitution
of the ectocyst is observed in Anguinella palmata, and may
therefore be expected to occur in others of the same family.
This peculiarity of the ectocyst, and the extraordinary length
of the cells, appear to constitute the chief distinctive charac-
ters between Farrella gigantea and what I take to be the
Avenella (Farrella) fusca of Sir J. Dalzell. For specimens

94 ZOOPHYTOLOGY.

of the latter species I am indebted to Mr. Wyville Thomp-
son; and from one of these, fig. 38, Pl. VI., has been taken
for the purpose of comparison; the two having been drawn
under the same magnifying power. It should be remarked,
however, that the specimen of the latter here figured was in
the dry state, and consequently is somewhat distorted. But
since these figures were printed I have met with a species
of Farrella, parasitic upon Flustra foliacea, dredged in about
20 fathoms of water off Tenby, which appears to correspond
with the Avenella fusca, and the examination of which in the
living state has satisfied me beyond doubt, that that form and
Farrella gigantea are quite distinct. In the * Annals of Nat.
Hist.,’ 2nd Ser., vol. xvi., p. 85, Plate IV., fig. 29, Mr. Gosse
describes and figures a Polyzoan belonging to the same
family, under the name of Nolella, which would appear
closely to approach in some respects, as he himself observes,
the Avenella of Sir J. Dalzell; and from the semiopacity
assigned to the ectocyst, it would also seem to correspond
very closely with the form above adverted to, as found upon
Flustra foliacea. ‘The characters, however, assigned by Mr.
Gosse to Nolella are apparently sufficient to remove all
suspicion of this being the case. He says, that the “ cells
are erect, subcylindrical, springing singly, but closely from
an undefined polymorphous incrusting mat ; the tentacles (18)
forming a bell.” A copy of Mr. Gosse’s figure of NV. stipata
is given in Plate V., fig. 4.

What is meant precisely by the expression “ undefined,
polymorphous incrusting mat,’ from which the cells spring,
is not very clear. In all known Vesiculariadan Polyzoa,
except Anguinella, the cells spring “ singly” from a common
tube; and if, as the use of the word “mat” might imply, the
** polymorphous crust” is composed of tubes, the character is
intelligible enough, and the species in accordance, so far, with
its congeners ; but if, as the expression might also be taken
to convey, and as the figure certainly indicates, this crust is a
continuous substance,—the condition is so peculiar as at once
to raise the genus in which it is found to the rank of, at
least, a distinct family group. It is more probable, however,
that upon farther examination Mr. Gosse will find that the
cells do really arise from a creeping adnate tube; in which
case the genus will fall to the ground, and Wolella stipata have
to be referred to Farredla, with the characters as here modi-
fied. If so, it would seem to correspond in all respects with
Avenella fusca, Dalzell; or, at any rate, with the form oceur-
ring in Flustra foliacea above noticed, and which, if not the
Avenella, is apparently as yet undescribed.

ZOOPHYTOLOGY. 95

Between Farrella (Laguncula) elongata, V. B. (Rech. sur
les Bryozoair.), p. 26, Pl. Il. (0), of which an outline sketch
(reduced from the original figure) is given in Plate VL, fig. 4,
and F, gigantea, the difference is sufficiently obvious. This
species has not yet, so far as I am aware, been observed upon
the British coast, though it will in all probability be found
to be a native.

The only situation in which F. gigantea has as yet been
met with is in the neighbourhood of Tenby, and there chiefly
in a cave in St. Catherine’s Isle, which is only open at spring
tides. In the autumn of 1854 the walls of this cave were
in parts densely covered with this Polyzoan, growing in a
close and thick pile, but inconspicuous among the numerous
Sponges and minute vermidoms of similar colour and aspect,
with which the surface of rock is covered. In the present
year, however, the species is far less abundant in the same
locality.

The species, as has been said, is remarkable for the
gigantic size of the cells, which are often more than 1-10th
of an inch in length, ‘The polypide, however, is not beyond
the average size in other Polyzoa. It has from 20 to 30 long
slender, highly flexible tentacles.

Gen. 2. Anguinella, V. B. Rech. sur les Bryoz., p. 58.

Char. Cells tubulous, cylindrical, supported on a common stem (one
springing from the base of another).

A, palmata, V.B. Pi. VI., figs. 1, 2.

The only species—
A, palmata, V. Bened. Rech. sur les Bryoz., p. 58. Pl. VIL., figs.
18, 24.
Hab. Ostend, Van Beneden; Britain, Busk; River Deben, Suffolk ;
Tenby ; Charleston, 8. Carolina, U. §., Harvey.

The very peculiar conformation of the polyzoary in this
species at once distinguishes it from all its congeners. It is
farther distinguished from most of them by the constitution
of the ectocyst, which contains imbedded in a soft, or rather
flocculent substance, so large a quantity of argillaceous and
silicious matter, that when exposed to the flame of a spirit
lamp, it is converted into a kind of red earthenware, retaining
its pristine form and dimensions, or nearly so.

It grows to a large size; many tufts or bunches reaching
three or four inches in length. It is found on dead or living
shells, and on stones, and closely resembles a small Fucus
covered with mud. This peculiar colour and habit have
probably been the reason that it has so long escaped notice
on our coasts, where it will, in all probability, be found to

96 ZOOPHYTOLOGY.

be pretty generally distributed, especially in muddy situations.
Its wide distribution in the world is indicated by its occur-
rence at such a distant locality as South Carolina, the speci-
mens from which in my possession were collected by Dr.
Harvey.

In the river Deben, in Suffolk, which is more properly
speaking an estuary than a river, scarcely a dead or living
oyster-shell can be dredged up which is not covered by it.
At Tenby it occurs, very sparingly, in the caves in St.
Catherine’s Isle.

ZOOPHY TOLOGY.

DESCRIPTION OF FIGURES.

PuaTE V.
Fig.
1.—Farrella gigantea, natural size.

2.—The same magnified.
3.—Mouth of cell, with the polypide partially extruded.
4,—Nolella stipata, Gosse.

PuaTE VI.
1.—Anguinella palmata magnified.
2.—Portion of cell, with polypide partially extruded.

3.—Outline sketch of Avenella fusca, which had been dried and com-
pressed.

4,—Outline sketch of Faurrella (Laguncula) elongata, Van Beneden.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE I.

illustrating Professor Gregory’s paper on some new species
of British Diatomacez.

N.B.—Most of the figures in this Plate have not been drawn to the
scale now usually adopted, of 400 diameters, but to a scale considerably
smaller, which, according to my estimation, does not much exceed 300
diameters. This remark applies particularly to the larger forms, such as
figs. 4, 5, 6, 7, 11, 28, 88. The reader is requested to bear this in mind,
when comparing these figures with those of the Synopsis of the Rey.
Professor Smith. As for the smaller forms, they generally vary so much
in size that the figures may be held to represent average individuals under
a power of rather less than 400 diameters.

I, Species new to Britain.

Fig. Fig.
1.—Eunotia tridentula, Ehr. (P. pachyptera, Ehr.? P.
2.—Navicula Trochus, Ehr. lata, Sm., var. ?)
3, dubia, Kitz. 7.—Pinnularia dactylus, Ehr.
4— , Bacillum, Ehr. 8.— 53 pygma, Ehr.
(qu. N. Americana, Ehr. ?) 9.—Stauroneis Legumen, Kiitz.
5.—Navicula (Pinnularia) nodosa, | 10.— = ventricosa, Kiitz.
Kiitz. 11.—Cocconema cornutum, Ebr.

6.—Pinnularia megaloptera, Ehr. | 12.—Gomphonema subtile, Ehr.

II. New Species, named by other writers, but not yet figured.

13.—Navicula apiculata, Sm. 15.—Navicula scutelloides, Sm.
4— ,, rostrata, Sm. 16.—Mastogloia Grevillii, Sm.

Til. New Species, now first named.

17.—Cymbella (?) sinuata, W. G. 33.—Pinnularia Elginensis, W. G.

oh ie turgida, W. G. 34.— * globiceps, W. G.
19.— ,, obtusa, W. G. | 35.—Stauroneis obliqua, W. G.
20.— ee Pisciculus, W. G. sof.— 4, » With sigmoid
21.— a Arcus, W. G. median line.
22.—Navicula cocconeiformis,W.G, | 36.—Stauroneis (?) ovalis, W. G.
23.— ,, lacustris, W. G. 37.— a dubia, W. G.
238.— ,, be var, 38.—Surirella tenera, W. G.

24.— ,, bacillaris, W. G. This form frequently occurs
25.— ,, lepida, W. G. twice as large as the
258.— ,, a VEEE figure, but with the
26.— ,, incurva, W.G. same proportions.

27.— ,, longiceps, W. G. 39.—Gomphonema insigne, W. G.
28.—Pinnularia biceps, W. G. Side view.

28B.— ,, is var. b. Front view.

29.— uf linearis, W. G. 40.— a ventricosum, W. G.
30.— ne subcapitata, W.G. | 41.— Re aquale, W. G.
3L— ms eracillima, W.G. | 42.— Y Sarcophagus, W. G.

2.— - digitoradiata, W. G. b. Front view.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE II.

Illustrating Mr. Busk’s paper on Sayitta bipunctata.
big.
1.—Sagitta bipunctata magnified, dorsal view.
a, @. Anterior pair of lateral fins.
b, b. Posterior pair.
ec. Caudal fin.
d. Spermatic cavities.
e. Hjaculatory sac.
2.—Dorsal aspect of the head.
2* ,—Inferior aspect of head and part of trunk, to show an appareut pro-
cess, observed on one or two occasions, probably a parasite.
3.—Ventral aspect of the head.
a. Oral denticles.
b. Mouth.
c. Hooks.
4,—Magnified view of posterior portion of trunk and part of the caudal
portion of the body.
a, a. Ovaries.
b. Placental tract.
c. Orifice of oviduct, which opens however above the fin and
not below it, as here represented.
d, Anal opening.
e, e. Hjaculatory sacs.
J, f. Spermatic sacs in the caudal portion of the body.
5.—A more highly-magnified view of one of the ejaculatory sacs, with
spermatozoa swarming about the orifice (viewed on the side).
a. The sac.
6.—A more highly-magnified view of one of the ovaries.
a. Placental tract, enclosing—
b. A cecal canal ;
c. Ova, still attached to the placental tract ;
d. Orifice of oviduct.
7.—Cephalic ganglion and its branches (Huxley).
a. The’ ganglion, composed of nerve cells in the central portion.
b, b. Anterior pair of nerves, going to supply the buceal
muscles.
c,c. Posterior pair, or optic nerves.
d, d. Middle pair, which pass downward on either side of the
cesophagus, to join the ventral ganglion.
zi, i. Optic ganglia, which, according to Huxley, are contained
in capsules.
k, k. The eyes.
l,l. A ganglioform enlargement of the optic nerve.
8.—The ventral ganglion.
d, d. Anterior pair of nerves, going to the cephalic ganglion.
e. A loose capsular investment of the ganglion.
Ff, f. Posterior pair of nerves.
g, g. Lateral nervules.
h, h. Central tract of white nervous matter.
9,—Spermatic vesicles and cells.
10.—Diagrammatic view of the nervous sy stem, taken from Krohn, with
the omission of the supposed posterior cephalic loop.
11.—Mature spermatozoa,
12 ss Saas te in various stages of development.
. Early stage. b. Later stage.

Nbick Sou Wg Lil BLL L

GBusk del Tuffen West. sc Ford & Wast Imp.

4
4

JOURNAL OF MICROSCOPICAL SCIENCE.

EXPLANATION OF PLATE IV.

illustrating Mr. Gorham’s paper on the Magnifying Power
of Short Spaces.

In the third horizontal column the single aperture which is held at the
distal end of the instrument is shown in four of its phases of revolution.

In the fourth horizontal column, is delineated one of the objects (equi-
lateral triangle) chosen for examination, and placed close in front of the
eye in the circular end of the instrument.

The first, second, and fifth horizontal columns show in their uncom-
bined state the planes which are formed by the mutual intersection of the
two upper series. Thus the lines one and five contribute to the produc-
tion of the planes nine, thirteen, and seventeen: the lines two and six to
the planes ten, fourteen, and eighteen, and so on.

In the lowermost column is shown the coalescence of these planes into
one entire form, the triangular prism, presenting itself in four different
aspects, in accordance with the inclination of the lines 1, 2, 3, and 4, in
the uppermost series.

Micro. Journ., Vol. IV., Pl. TV.

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ORIGINAL COMMUNICATIONS.

On Certain Convitions of the Dentat Tissues. By Joun
Tomes, F.R.S., Surgeon-Dentist to the Middlesex Hospital.

Tue temporary teeth, when about to be replaced by the per-
manent set, lose their fangs by gradual absorption of their
substance. The crown, when thus left, having but little hold
upon the gum, soon falls out. The manner in which the
absorption of the dental] tissues is effected has been described
in a paper published in the “ Philosophical ‘l'ransactions,”’ in
1853. The subject is there mentioned in connection with the
absorption of bone.

Having latterly had occasion to devote considerable attention
to the phenomena attending the casting off of the deciduous
teeth, several conditions relative to absorption have come
under my notice, which, as applied to teeth, had, I think,
hitherto escaped observation. It may, however, be here
stated, that the more recent examinations have not led to any
modification of the opinions upon the subject of absorption
advanced in the paper alluded to, but have served rather to
confirm the statement there made. Absorption may com-
mence upon any part of the fangs of a tooth, and at several
points at the same time. By the gradual extension of this
process, both in depth and superficially, the root of the tooth
is wasted, till, at last, nothing is left but the crown, and even
this part is often so much hollowed out, that, excepting the
enamel, but little of the tooth remains. The cementum is
first attacked, then the dentine disappears, and the enamel at
those points where the dentine has been entirely removed
suffers from the same action. But whichever of the three
tissues is attacked, we see the same characteristic surface as
that shown by bone when undergoing a similar action, namely,
a surface full of deep indentations, as though they had been
made by a sharp piercing instrument, having a semicircular
extremity. These minute holes or depressions proceed in
various directions, several advancing from contrary points
towards the same spot, not unfrequently isolate pieces of
dentine. If a setion be taken through the substance of a
tooth, so as to cut the wasting part at a right angle, we shall
find the surface acted upon to have an irregular festooned
outline, so characteristic, that when once seen it cannot fail to
be again recognised,

VOL. IV. u

98 TOMES, ON THE DENTAL TISSUES.

It has been stated that, closely applied to the surface, a
cellular mass will be found, and that this is but slightly
adherent, the wasting and growing surfaces readily parting,
unless the two are held together by the irregularities on the
surface of the former. It will sometimes happen that the
cellular mass penetrates into the dentine through a small open-
ing, and there dilates, in which case its withdrawal becomes
impossible. This condition is now and then found on sec-
tions prepared for the microscope, when we have an oppor-
tunity of examining the two tissues im situ. Indeed we shall
find a few cells adherent to the surface of the dentine where
less deep burrowing has occurred. ‘The cells themselves do
not present any peculiarity by which they could be readily
recognised, if separated from the part undergoing removal.
They are small granular cells, of a more or less spherical
form. If a tooth which has lost its fang be carefully re-
moved, we shall find remaining in its place a growing papilla,
corresponding exactly in size and form to the surface from
which it has been separated ; and this separation may often
be effected with so little injury to the absorbent organ, that
no blood appears upon its surface after the operation, although
the organ is highly vascular and readily torn.* The superficial
extent of the papilla will be equal to that part of the tooth
undergoing waste, but the extent, as regards depth, is slight,
for, as the root of the tooth disappears, the socket is con-
tracted by the deposition of bone, which forms at the base of
the absorbent organ as rapidly as the cellular surface en-
croaches upon the tooth, The cases in which we find an
exception to this condition are those in which the permanent has
advanced close to the fangs of the temporary tooth, when the
crypt containing the one communicates with the socket of the
other, the rate of growth of the permanent having been greater
than the absorption of the deciduous organ; but even in these
cases we may generally observe some part in Which the con-
traction of the socket is coincident with the absorption of the
occupant fang. From the following quotation, it does not
appear that Mr. Bell observed these conditions :—

‘It has been already stated, that the permanent teeth during their
formation are crowded tugether in the jaw, by being placed in a smaller
arch than they would occupy if regularly placed side by side. As the
latter, however, is their destined situation, we find that as soon as they
are advanced to a certain point of their formation, and can no longer be
_ contained within the alveoli, absorption takes place in the anterior parietes

* Laforgue and Bourdet recognised the presence of the absorbent organ,
but supposed it exhaled a fluid capable of dissolving the roots of the
temporary tooth.

TOMES, ON THE DENTAL TISSUES. og

of the cavities, by which means the teeth are allowed to come in some
measure forward. In consequence of this absorption it often happens,
that not only the socket of the corresponding temporary tooth, but that
of the tooth on each side is also opened to the permanent one. Absorption
now commences in the root of the temporary tooth, generally on that
part nearest its successor, and thus goes on by degrees as the latter
advances, until the root is completely removed, the crown at length falls
off, leaving room for the permanent tooth to supply its place.”

Mr. Bell, however, rejects the idea that mere pressure of
the one tooth against the other has anything to do with the
absorption of the first set ; an opinion that he would probably
have expressed even more strongly, had he observed the
shallow but perfect sockets which are formed when the tem-
porary teeth are shed before their successors are ready to
appear. This, however, must be a very common condition,
as I have in my own collection several specimens illustrating
the point.

The fact was not overlooked, I think, by Hunter, although
his description is not very clear. He states at page 99 in his
‘Natural History of the Teeth:’ “The new alveoli rise with
the new teeth, and the old alveoli decay in proportion as the
old teeth decay ; and when the first set falls out, the succeed-
ing teeth are so far from having destroyed by their pressure
the parts against which they might be supposed to push,
that they are still enclosed and covered by a complete bony
socket. From this we see that the change is not produced by
a mechanical pressure, but by a particular process in the
animal economy.”

But there is still a disposition on the part of many who are
intrusted with the treatment of teeth, to attribute the absorp-
tion of the roots of the one tooth to pressure occasioned by
the growth of its successor, and the development of the per-
manent may have something to do with the shedding of the
other. But this does not offer a satisfactory explanation of
all the circumstances attending the absorption of the fangs of
teeth. In the first place we sometimes meet with cases in
which the fangs of permanent teeth are as completely ab-
sorbed as those of the temporary organs. Then, again, the
fangs of temporary teeth, which have no successors, are also
absorbed. These circumstances, taken with the hitherto
overlooked fact, that with the waste of the temporary tooth
we have pretty generally a corresponding development of
bone within the socket to be removed before the permanent
tooth appears through the gum, render the pressure theory
somewhat unsatisfactory. Another condition may be ad-
duced, tending also against that opinion, namely, that tem-
porary teeth occasionally maintain their place to the exclusion

H 2

100 TOMES, ON THE DENTAL TISSUES.

of the permanent ones, which are then kept within the
substance of the jaw, or appear in some unusual posi-
tion.

The relations as regards time between the absorption and
shedding of temporary teeth and the appearance of the suc-
ceeding permanent teeth, are by no means constant. In some
cases the temporary teeth are thrown off two years before the
corresponding permanent ones come through the gums. In
others, again, the new will replace the old ones in as many
weeks or even days.

Before the laws which regulate the absorption of the fangs
of teeth can be fully recognised, a more perfect knowledge
of the condition attending the process must be acquired.
Recent examinations have enabled me to add the following
additional facts bearing upon this subject to those already
known. The process of absorption once commenced, it
appears to have been assumed that the same action would
be continued, with more or less rapidity, until the tooth falls
out; or if not continual, is suspended only. Such, however,
is not constantly the case. Not only is the action of absorp-
tion suspended, but one of development takes its place. We
find the excavated surface of the dentine cementum and enamel
covered with cementum, the latter following all the irre-
cularities of the former tissues, and closely united to them.
In cases where this development is going on, or being set up
is maintained, the teeth afford considerable resistance when
their removal is attempted. In those instances where the first
teeth have remained, and tend to the displacement of the
second set, this deposit of cementum will be found to exist in
considerable quantity.

The development of bone upon the surface which had
formerly been the seat of absorption, by no means indicates
that the tooth will not again be subject to destructive action,
On the contrary, specimens in my collection show that the
bone deposited under the above circumstances may itself
become the subject of absorption, that this process may be
again suspended and development be renewed, that the absorp-
tion may again take the place of development; in fact, that
wasting and reparation may alternate until by the preponder-
ance of the former the tooth is shed. In sections of teeth
showing this peculiar condition of development, we may find
upon the growing bone numerous osteal cells, with here and
there a Jacunal cell. A bone dacuna, situated within a semi-
circular indentation in the dentine, gives the appearance of a
lacunal cell, and a dacuna similarly situated in the cementum
(a circumstance of common occurrence), has possibly been

TOMES, ON THE DENTAL TISSUES. 101

supposed by Mr. J. Salter to be what has been described in the
paper before referred to as a Jacunal cell.*

The part of a tooth which has the greatest power of resisting
absorption, is that in immediate contact with the pulp. We find
examples in which a thin shell of dentine surrounds that organ,
while that around it has been in great part taken away. This
is, however, eventually removed, and the pulp itself changes
its character, and becomes an absorbeut organ, or makes way
for that which is. In a fortunate selection we may find sec-
tions showing in one part dentine which has been but recently
formed, with its modular outline and contiguous cells, capable
of developing dentine; in another part absorption in active
progress ; and in a third the deposition of bone on the surface
of the wasted dentine. In no instance, however, have I seen
dentine deposited upon the surface of that which has been
diminished by absorption.

It would appear that the dentinal pulp, although its func-
tion may be changed into that of absorption, or its place be
taken by an absorbent organ, and this, again, changed to one
for the development of bone, is incapable of resuming under
any recognised circumstances its primary function of dentinal
development. In other words, that a portion of dentine when
removed by absorption, cannot be replaced ;+ while in bone,
or cementum, the removal of a lost portion is of frequent occur-
rence, Sections taken from the teeth of adults seldom fail to
exhibit points where the cementum has been removed and
again added ; and very commonly the absorption has at points
extended a short distance into the dentine, and the lost parts
made good with cementum. ‘This condition may be observed
in perfectly sound teeth; but in unsound ones, where the
cementum exceeds the normal amount, the removal and renewal
of tissue is still more marked. If the section be so made
as to give a view of the surface of the pulp cavity, we shall

probably find evidence of the pulp after the full develop-

* Transactions of the Pathological Society, vol. vi., p. 169.

+ Since the manuscript was sent to the Editors of this Journal, I have
seen a paper published in the last number of the Guy’s Hospital Reports,
by Mr. J. Salter, ‘On Intrinsic Calcification of the Permanent Tooth-
pulp.’ Mr. Salter describes a section taken from a carious temporary
molar, which was removed from the mouth of a person aged 18 years.
The author states, that the “‘ pulp was found converted into a mass of
crusta petrosa and dentine confounded together.” ‘The drawing is beauti-
fully executed, and shows, by the usual indications, that the pulp-cavity
has been enlarged by absorption of its parietes. Judging from a view of
the engraving only, it would appear that the tissue in contact with the
wasted dentine is cementum only, while the newly-developed dentine is
limited to the inner portion of the mass, If this view be correct, the
specimen would have served for the illustration of the present paper.

102 TOMES, ON THE DENTAL TISSUES.

ment of the tooth, having resumed its full formative powers,
and produced new, or secondary dentine, the action having
been excited either by the wearing away of the tooth or
by the presence of caries. If the irritation be continued
until it extends down the fang as far as its extremity, and
signs of inflammation show themselves, the aperture of the
fang will become enlarged by absorption, and after awhile the
enlargement is continued to a considerable distance up the
root of the tooth. The canal may be again contracted by the
formation of dentine, or by the development of cementum ; and
I have seen one or two instances in which the greater part of
the pulp cavity in permanent teeth has been lined with
cementum. ‘This condition of tissues is very common in teeth
that have been long the subject of caries, but I believe it is
not confined to carious teeth. I have several specimen of
temporary teeth, in which the lower part of the root has
suffered from absorption, and then has become the seat of
deposition of cementum, leaving only a small canal in the
centre. High up the root small patches of dentine have been
removed, some of which only have been made good with
cementum, while the contiguous parts have retained their
usual condition.

It will be seen that the foregoing facts bear upon the
opinions advanced by Mr. De Morgan and myself, in the
paper on the structure and development of bone, before
cited ; that we have indications in teeth, as in bone, of alter-
nations, of removal, and deposition of tissue. In the young
subject, the development of bone tissue is in excess of absorp-
tion, allowing the bones to increase in size ; that in middle
life the two powers, under ordinary circumstances, balance
each other, and the bones preserve their adult dimensions ;
while in old age the absorbent action appears to prepon-
derate. Conditions pretty nearly parallel occur in the dental
tissues after the temporary tooth has been fully formed; por-
tions of cementum are removed, and with it, in some cases, a
little dentine; the lost parts are replaced by cementum, and the
tooth is again perfect. When the time approaches for shed-
ding the teeth, the two actions alternate; but the absorption
being in excess of the development, the tissues disappear,
and the tooth is shed, After the formation of the permanent
teeth we have occasional alternatives of the two actions; but
they are balanced, and neither increase or diminution of size
is observed. But as age comes on, it often happens that
absorption is in excess, the fangs diminished in size, the teeth
become loose, and fall out.

TOMES, ON THE DENTAL TISSUES. 103

Observations on the Structure of the Enamel.

Without going fully into the structure and development of
the enamel, and into the citations of the opinions published
upon the subject, I wish to take this opportunity of recording
certain observations which I have made upon that structure.
The transverse striation of the enamel fibres has been fre-
quently remarked, but the cause of these markings has not
been determined. If sections from a number of teeth be
examined, it wili be found that the striae are much more
strongly pronounced in some specimens than in others, and
most especially so in those in which parts of the tissue have a
brown colour when seen by transmitted light.

The markings crossing the direction of the fibres are of
two descriptions. The one arranged in contour lines, and
situated at irregular distances from each other, uncertain in
number and extent, and sometimes altogether absent. The
other kind minute and regular, extending from fibre to fibre,
and strongly resembling the transverse markings in voluntary
muscle. In the present instance my remarks will be confined
to the latter kind of markings.

In unhealthy subjects the permanent teeth, when they
appear through the gums, are not unfrequently destitute of the
brilliant white colour common to the finely-developed organs
of a healthy child; on the contrary, they have an opaque
yellow colour. If such teeth be selected for examination, we
shall find that the sockets, when reduced sufficiently thin to
be seen by transmitted light, present in the enamel a confused
opaque appearance; but if a tolerably high power be used
(such as the quarter or eighth object-glass) in conjunction
with a strong light, the dark appearance will resolve itself into
a series of lines; the one set marking the course of the fibres,
the other taking the direction of the transverse stri¢. The
two sets of lines crossing each other at right angles leave inter-
spaces approaching a square form. ‘These interspaces are
fitted with granular masses, having the appearance of cells.
By treating the section carefully with dilute hydrochloric
acid, these appearances become more distinct, and we then
have series of parallel fibres composed of distinct sheaths,
each containing a line of granular cells or meshes arranged
in a single series, presenting a strong resemblance to the
ultimate fibrilea of muscles, That such is the true structure
of enamel is, 1 think, satisfactorily proved by specimens in
my collections, some of which show the cells or granular
masses; whilst others show the sheath, with the contents
remoyed, Other specimens, again, show the enamel fibres in

104 “TOMES, ON THE DENTAL TISSUES.

the very young subject, deprived of their salts, detached from
each other, and floating about in the fluid in which the section
is preserved.

The figures illustrating these forms were drawn from
specimens which retain the conditions figured. The appear-
ances described do not admit of dispute ; but the interpre-
tation of their origin may perhaps be differently given by
observers who do not agree upon the manner in which the
enamel is developed. I do not propose to enter upon the
question of development; but shall for the present leave the
subject, after stating the varying conditions of enamel as it is
found in human teeth.

In well-formed teeth, although the cell-like markings in the
enamel are not by any means as distinct as in teeth in the
condition I have described; yet having first examined the
latter, but little difficulty will be experienced in recognising
here and there faint indications of a similar structure, espe-
cially if the light be well managed. The more perfect the
development of the tooth, the more transparent and free from
markings will be the enamel, when seen as a microscopic
object ; and the less perfect the more distant will be the
columns of granular cell-fibres.

Examples may readily be found in which the union be-
tween the enamel fibres is so defective that the tissue readily
breaks down; a condition rendering it very difficult to grind
it sufficiently thin for microscopic examination. When ob-
tained, however, such specimens are very instructive, as they
show distinctly the individual fibres and their contents, which
in the most highly-developed tissue are so perfectly fused
together, that the strongly-marked distinction of parts, which
is so obvious in the one, is almost entirely lost in the other.

From what has been stated it will be seen that my view of
the structure of enamel is as follows :—

The enamel fibres are composed of a sheath containing a
series of cells or masses; that in perfectly-developed enamel,
the cells or masses and sheaths are so blended that but slight
distinction of parts remains, but that in less perfectly de-
veloped tissue the component parts remain visible.

(To be continued.)

ON THE FILAMENTOUS, LONG-HORNED DIATOMACE. 105

On the Finamentous, Lonc-HorNED Diaromacrem, with a De-
scription of two new species. By Tuomas Bricurwe tt, F.L.S.

In a gathering of Diatomacez, made by the late Mr. Wigham
in July 1854, on the borders of the salt-water estuary, called
Breydon, near Yarmouth, a singular filamentous, horned species
was detected, allied to the genus Chetoceros of Ehrenberg.

An examination of this singular organism, (the first of the
family which has occurred in this country ), aid a comparison
of it with the allied forms described by Ehrenberg and Dr.
Bailey, afford materials calculated to extend and correct our
knowledge of this rather doubtful group of Diatomacee.
Mr. Wigham’s discovery will also, we trust, induce surviving
labourers in the same field, to endeavour to add to our know-
ledge of existing species, as much must yet be brought to
light before a satisfactory classification of this group can be
effected.

Most of the described species have been found only ina
fossil, or rather, if we may so term it, a deposit state ; and in
this state it is clearly difficult to form a correct idea of either
species or genera, since deposits give no information as to the
Diatoms being in threads or solitary frustules.

From this circumstance, and a disposition to describe every
variety of form, and even many fragments of Diatoms, as
species, both species and genera have been multiplied to a
perplexing extent. It appears probable that there are few, if
any, instances of truly fossi/ Diatoms, but that all the so-called
fossil species are only deposits fain still-existing and living
species ; and it is only when we have the living Wiatati before
us, that we can give any specific or generic characters that
can be at all relied upon.*

The discovery of a new and living species of Chetoceros, and
a careful examination of most of the species of this and seve-
ral other allied genera, described by Ehrenberg as found in a
fossil state, have satisfied us that most, if not all these, will,
when found in a living state, turn out to belong to the singu-
lar filamentous and horned group, which may for the present,
with some extension of its character (such as is hereafter
attempted in this paper), be comprehended in the genus
Chetoceros.

The typical species of Ehrenberg’s genus appears to be C.

* In proof of this, Ehrenberg’s genus Biblarwm seems entirely composed
of the disjecta membra of several genera, as Tetracyclus, Odontidiuwm, and
some others. Tetracyclus emarginatus, Wm. Smith, (biblarum emargina-
tum, Ehr.,) has been found recently, in a living state, both in Ireland and
Scotland.

106 BRIGHTWELL, ON THE FILAMENTOUS,

didymus. This occurs not unfrequently in guano. The horns
proceed immediately from apertures on each side of the frus-
tules (an essential character of Ehrenberg’s genus), and differ
in this respect from our newly-discovered species, in which
the horns proceed from, or rather are an elongation of the
intermediate rings.

Two species from the Antarctic Sea are briefly described by
Ehrenberg (C. dicheta and C. tetracheta); each frustule is
smooth, and the horns (of which the former species has two
on each side, and the latter four) are very long and filiform.
These species were, we believe, found in pancake-ice, and
were brought home by Dr. J. D. Hooker.

Two species from Bermuda earth, marked as doubtful, are
described by Dr. Bailey (C. bacillaria and C. diploneiis),
and he has also recently described and figured a remarkable
species, named by him C. boreale, found in the stomach of
Botriodactyla grandis.* The horns of this species are very
long, and armed with numerous minute spines. Dr. Bailey
describes and figures a small species also found in guano,
named by him C. incurvum, which we have found plentiful
in South American guano,

Of the allied genus Goniothecium, eight species are de-
scribed by Ehrenberg, all found in the Richmond earth, North
America. The two largest and most common are G. Rogersii
and G. odontella, and we think it probable these will turn out,
if discovered in a recent or living state, to be Chetocert. Of
the remaining six species, we are led to conclude, from the
discovery of the Breydon species, that two of them belong to
the genus Chetoceros, and are, when living, filamentous. ‘They
are Gontothecium gastridium, of which we have found many
specimens with the horns perfect, and G. crenatum. A figure
of a frustule of this species is given in the Microgeologie of
Ehrenberg ; and it can scarcely be distinguished from the
frustules of the Breydon species. Similar frustules are of fre-
quent occurrence in African and other guano, and in several
fossil earths of marine formation, and we have detected recent
specimens in a gathering lately sent us from Monterey Bay,
North America. Goniothecium hispidum and G. didymum of
Ehrenberg, scarcely appear to differ from some of the smaller
frustules of the Breydon species. G. navicula and G. barbatum
are marked by Ehrenberg as doubtful species of Goniothecium ;
but are clearly allied to G. crenatum, or our Breydon species.

Several other fossil genera of Ehrenberg contain species
which will probably be found to belong to the long-horned
filamentous Diatoms. Xanthiopyxis cingulata has precisely

* See Smithsonian Contributions to Knowledge, Feb. 1854, pp. 8, 9.

—

LONG-HORNED DIATOMACE. 107

the cup-shaped and hispid character of our Breydon species,
but is destitute of the neck. Syndendriwm diadema and Di-
cladia capreolus are common species; they are found with the
other Chetoceri, in various earths, and guano, and appear to be
of the same family. They are chiefly distinguished by long
styles, proceeding from the rounded end of the frustule, which
styles are branched at the end, and are not unfrequently found
with a portion of the membrane adhering to them, in which
they seem to have been imbedded. Omphalotheca hispida has
the appearance of an imperfect frustule, and Mastogonia pre-
texta, of a semi-frustule of Goniothecium Rogersii.

We venture to give a synopsis of the Chetoceri, adapted to
our present imperfect state of knowledge of these singular
organisms.

CH2&TOCEROS.

Filamentous ; filaments elliptical, fragile, imperfectly siliceous. Frus-
tules without striz, united in pairs by the interlacing on each side, of
horns proceeding from the frustules, or from a cingulum between the
frustules. Horns often of great length, and sometimes spinous, or

serrated.
§ Horns, four on each side.

1. C. Tetracheta, Ehrenb., Kutz., spec. Alg. 138.

§§ Horns, two on each side, and proceeding from tubular apertures
in the frustules.
* Horns filiform.
. CO. Dicheeta, Ehrenb., Kutz., spec. Alg. 138.
. C. Didymus, Ehrenb., Kutz., spec. Alg. 138.
. 0.2 Bacillaria, Bailey, Kutz., spec. Alg. 1388.
. 0.2 Diploneiis, Bailey, Kutz., spec. Alg. 1388.
. C. Gastridium, Goniothecium Gastridium, Ehrenb., Kutz., spec.
Alg. 23. See Plate VIL., figs. 3—8.

N.B.—To Ehrenberg’s description should be added, ‘‘ Cornubus
utrinque duobus.” This species clearly belongs to the genus
Cheetoceros. Many examples have occurred with the horns
perfect. See Plate vii., fig. .

7. C. incurvum, Bailey. Smithsonian Contributions, Feb. 1854, p. 9.
Plate VII., figs. 9—11.
We have found this species abundant in guano.
Mr. Tuffen West has detected in guano frustules of a species, belonging
to this section, which is new to me, and may perhaps be C. Bacillaria,
Bailey. For figures of these frustules see Plate VIL., figs. 1, 2.

** TTorns spinous, or serrated.
8. C. boreale, Bailey. Smithsonian Contributions, Feb. 1854, p. 8.
Plate VII., figs. 12—15.
9. C. Peruvianum, Brightwell. Frustules hemispherical. Horns pro-
ceeding from the centre of the circular end; very stout
and long, and beset with short spines, recurved.

Doe wb

* T am also able to state, that C. Wighamti and Goniothecium his-
pidum have lately been gathered in the bay of the Isle of Roa, near
Ulverstone.

108 ON THE FILAMENTOUS, LONG-HORNED DIATOMACE#,

In guano from Callao, occurring in small flakes or patches full of pieces
of the horns, and a few detached frustules. Plate VIL., figs. 16—18.

§§§ Horns proceeding from a cingulum or ring, dividing the frustules.

10. C. Wighamii, Brightwell. Frustules cup-shaped, with a band round
the mouth of the cup, and a neck or bulb, proceeding
from the centre Frustules beset with minute short
spines, or papilla, in all parts, except the band. Oval,
on a front, or end view, the spines appearing as minute
specks. Boiled in acid, the filaments break up, and
the frustules, in an isolated state, and detached rings,
with the horns proceeding from them, are all that can
be detected. The rings may readily be distinguished
from the frustules seen endwise, as they are open, and
without dots; while the frustules, seen endwise, are
dotted.

In brackish water, near Breydon, Great Yarmouth. Plate VIL., figs.

19—36.

We have named this species after the discoverer, Mr. Wigham, an
excellent practical botanist, indefatigable in the pursuit of his favourite
study, and most liberal in his communications to his friends,

11. C. erenatum. All these species are described or figured by Ehren-
12. C. hispidum. berg, from frustules found in a fossil, or deposit
13. C. navicula. state, and appear to belong to this section of the
14. C. barbatum. genus Chcetoceros.*

The C. Wighamii was, as before stated, found near the salt-water
estuary, called Breydon, at the point where the rivers Yare and Waveney
meet. It occurred in a gathering made from a dirty ditch of brackish
water, at the back of a small public-louse, called ‘“‘ The Burney Arms,”
which is marked on the Ordnance maps. ‘The gathering abounded in
Campylodiscus clypeus (a species chiefly known before as occurring in
fossil earth from Bohemia), and in one or more species of Mastogloia ;
it also contained Bacillaria paradoxa, Amphora salina, Navicula palpe-
bralis and tumens, Melosira varians and subflexilis, and the Ulva bullosa (?);
and Protococcus hcematodes (?) abounded also in it, with which last the
Chcetoceros seemed most associated. It was perhaps parasitical on some
Alge, and, after being detached, had floated to where it was discovered.
This place has been frequently visited since Mr. Wigham’s decease, and
searched in vain, for the Cheetoceros ; although most of the above species

* We subjoin a reference to the figures of most of the species above referred to,
given in the Plates to Ehrenberg’s Microgeologie.
Mastogonia . . pretexta, Plate XIX. 15.
Goniothecium . . Rogersii . Plate XVIII. 92.
odontella Yo) Plo) Sega.
gastridiumi is) isi AGRE:
GidyMUM cut el Oa

a navicula ty Sale Ae Ss
ip hispidum’? 14 0.) "er, soles
barbatum =. . 106.

+ . .« crenatum, Plate XXXIX, 2. 74,
Chetoceros . . didymus, ,, XXXV. A. XVIII. 4, and XVII. 5.

Xanthiopyxis . . cingulata, ,, XXXII. XVII. 18.
Chetoceros . . diploneiis ere ae
Syndendrium . . diadema, Plate XXXV. A. XVIII. 13,
Dicladia’’ 4. 4°. «capredlus, . ‘SSS eA
Omphalotheca . . hispida .« Jo Ay EG 4.

HEPWORTH, ON THE MICROSCOPE. 109

were met with. In the living species of C. Wighamii, the endochrome
was seen of a green colour, and aggregated in the centre of each frustule,
in the manner represented in the figures of Hncampia zodaicus, in Kutz.
Bac., Pl. XXL, fig. 21, and Pritchard’s Infusoria, Pl. XIII, fig. 48. No
appearance of conjugation has been observed, nor have we been able to
detect in this, or any other of the species, mentioned in this paper, which
have come under our observation, any striz, or markings of that kind.

We have detected most of the species above described in
guano (chiefly from Callao), and especially in little transpa-
rent flakes or patches containing a mass of frustules. C.
gastridium, incurvum, Wighamii, and Peruvianum are of most
frequent occurrence.

There can be little doubt that all the guano of the coast of
Peru is in like manner pervaded with these organisms, and if
so, we ought to look to this locality for living species. C.
Wighamii has, as we have already stated, been lately gathered
in Monterey Bay, and a careful search would probably bring
other species to light.

The discovery of a number of specimens of C. boreale in
the stomach of a large species of Holothuria, or Sea-Cucumber,
should lead to the examination of the stomachs of Sea-Slugs,
especially of such as are known to feed on marine Alga, for
specimens of this singular and interesting group of Diato-
macee.

OxsERVATIONS on the PracricaL Apriication of the Micro-
score. By J. Hepworrn, Esq.

THERE are yet some parties in the medical profession who
are sceptical as to the utility of the microscope. I have
found it occasionally of practical importance ; and perhaps if
I mention a few cases, it may not be uninteresting to the
medical readers of the ‘ Jovrnal.’

J. M., a young man, aged twenty-three, applied to me,
bringing, in a bottle containing some fluid, a lock of hair, and
stating that he had vomited it in the night; that he believed
it had been in his stomach three months, during most of
which he had been under medical treatment for almost con-
stant vomiting, and he thought this had been the cause. I
examined the hair, and from the fact of the bulb and sheath
being complete, I concluded it had not been in the stomach
at all, or the gastric fluid would have dissolved these
portions of it. I suggested that it might have been thrown
into the vessel into which he vomited: that was found to be
the case, on inquiry, although he left with an impression that

110 HEPWORTH, ON THE MICROSCOPE.

I was mistaken. ‘To my surprise (in so young a man) | found
abundance of Sarcina Ventriculi amongst the secretions attached
to the hair. I prescribed, and the man got well in three
weeks, Had I not accidentally made the discovery, he might
have gone on vomiting three or six months longer.

J.W., aged twenty-eight, complained of great pain and irrita-
tion on micturition, and stated that he passed great quantities
of matter. On examining the secretion, | concluded from its
appearance, together with the symptoms, that the matter it
contained was pus; but with the aid of the microscope |
found it to be triple phosphate. I mentioned this case to a
friend, a (microscopical) sceptic, who observed that I might
have ascertained that by chemical analysis. I admitted it ;
but such a tedious process would have taken up too much
time ; whereas, with the instrument, I convinced myself of
the fact in a few seconds, and was able immediately to give
an opinion as to the probable result. I may further state,
that the man, although so young, had lost all his upper teeth,
and the first step towards his improvement was to procure an
efficient set of these necessary articles: this he succeeded in
doing (thanks to the dentists), and there was a gradual return
to health, which I attribute more to the dentist’s skill than to
any other remedy.

T. V., a boy five years old, had general anarsarca after
scarlatina: there was a brownish deposit in the urine. On
examination I found it contained altered blood discs (having
the appearance of toothed wheels), triple phosphate, abund-
ance of casts of the tubuli uriniferi, and, I thought, a few pus
globules (they might be mucous), but no brown epithelial
scales, which is a usual accompaniment with casts, as far
as I have remarked. The urine coagulated on the addition
of nitric acid. These appearances told a tale, which could
not have been so fully known without the aid of the micro-
scope.

I received from a friend a substance stated to be a portion
of a concretion passed per anum by a patient at the Man-
chester Infirmary: the case was one of Dr. E. Wilkinson’s,
who has kindly furnished me with some particulars, a few of
which I shall state. R. L., extat fifty-two, a weaver, four
years ago began to complain of pain in the stomach and right
side; it was so severe at times that he could not retain the
erect posture : soon after he perceived a fulness in the side,
the tumour gradually increased, and about two years ago

GREEN PIGMENT-DEGENERATION OF THE HEART. 111

he, with severe pain, passed a hard, flattened, spherical con-
cretion, of a light-brown colour, about two inches in diameter.
His diet consisted principally of oatmeal and milk. ‘The
tumour still remains, and occupies a large portion of the
abdomen. The concretions (of which he has passed several
about the same size and character) appear to consist of com-
pact masses of the beard of the oat.

Mrs. G. brought her son, a boy four years of age, who, she
feared, bad got the itch: the eruption appeared suspicious,
but did not occupy the usual situations on the body. With a
small pair of curved scissors I snipped off a pustule, in which
I detected two ovaof the Acarus Scabiei: this settled the matter
at once.

This leads me to state that I have never seen a good repre-
sentation of the mandibles of the Acarus. In a large and
beautiful engraving, in the possession of a friend, there is
only a slight indication of teeth up the centre of the head, as
though the mandibles were single members. Having
recently mounted a specimen, which shows the part so well,
I have given a drawing (Plate VIIL., fig. 3) ; also the mandibles
of some other Acaride. A mandible consisting of a single
member, appears, so far as my observation goes, to be the ex-
ception and not the rule in the Acart.

The mandibles of Acarus of the domestic Fly (fig. 6)
appear to bea pair of simple forceps; whilst those of the
Water Rat (fig. 14) seem to be a combination of forceps
and scissors. There are two Acari of the Mole (which has
its peculiar Flea, also), one (fig. 11) with the mandible fur-
nished with four barbed hooks, and the other (fig. 12) with
only a single hook, similar to that of the rabbit (fig. 13). All
the other specimens have double crab-like members.

On a Casy of GREEN PicMENT-DEGENERATION of the Heart.
By Dr. Tuupicnum.

In March last I gave to the Pathological Society of London
an account of a case of green pigment degeneration of the
heart, which has been published in the sixth volume of the
Transactions of that Society. In a foot-note on p. 141 of the
Transactions, I stated that I had since had an opportunity of
examining the heart of a man, aged fifty-four, who died of
disease of the brain (apoplexy from atheromatous arteries),
which presented features analogous to those described in my
first observation.

112 CASE OF GREEN PIGMENT-

This case I have thought myself justified in recording at
full length in this Journal, together with some observations
on the present state of the question.

The aorta was in a state of atheromatous degeneration,
with numerous scales of calcareous deposits.

The /eft ventricle was hypertrophied to an enormous extent,
the walls being nearly an inch in thickness. The microscopic
examination gave the following result :—

The muscular fibres from the outer wall show a granular
deposit of a dirty-yellowish colour. The granules are of all
sizes and shapes (Plate IX., figs. 1, 2), with a dark outline
when well focussed. Their colour is deeper in some parts
than in others; in some places it is a pale, dirty-yellowish
tint, in others sap-green. The granules are deposited in
patches, length-lines, mostly in the axis of the fibre, or singly,
scattered about, all apparently inside the sarcolemma. The
patches are very often broad and at regular intervals, so that
it seems as if they represented transformed nuclei (fig. 2 5),
particularly as the nuclei themselves are broad, nearly square,
with rounded-off angles (fig. 2a). In some places the deposit
is principally conspicuous at both ends of a nucleus (fig. 2).
The fibres themselves have preserved their transverse striz ;
numerous length-lines run along the fibres parallel with their
long axis, and crossing the transverse stria, which thence
appear as if they only reached from length-line to length-
line (Plate [X., fig. 1).

Acetic acid dissolves the fibres, and leaves the nuclei and
the unchanged granular deposit conspicuous,

Though the muscular fibres have a greenish tinge when
lying in thick layers, yet this tinge disappears when they
are lying singly, and when acetic acid is added, then all
tinge, except that of the green corpuscles, disappears.

The septum atriorum showed less deposit in its fibres,
which were however more macerated ; its striz were scarcely
distinct as such, but gave the fibres an irregularly-shaded
granular appearance, like figs. 2, 3.

In one of the right trabecule where the fibres are most
friable, and break into debris on preparation for microscopic
examination, the general tinge is deepest, but the deposit,
though consisting of many granules, is not very conspicuous,
because the granules are very small.

The right ventricle is in a state of atrophy, in every respect
the reverse of the left. The walls are thin, flabby, and tear
like rags. Their fibres are atrophied, pale, and very friable ;
great masses of fat-cells, or oil-drops, and globules of all sizes
are scattered through their tissue. Smaller fat-drops of the

DEGENERATION OF THE HEART. 113

usual bluish-white colour, with the dark outline, are seen inside
the sarcolemma along with the fine granular deposit. The fat,
or oil-drops, from the largest to the smallest (fig. 3 b), become
beautifully conspicuous on addition of acetic acid, and so do the
granular-yellowish and green corpuscles (fig. 8 a), which thereby
manifest themselves as being a distinct deposit, and not «
deposit of fat, as encountered in what is commonly called
fatty degeneration (fig. 3).

A small specimen boiled in ether showed the solubility of
all the fat globules in ether, since the granular-yellowish and
green deposit remained unchanged. On the ether cooling
and acetic acid being added, oil-globules were precipitated
again. ‘They adhered to certain projecting parts, or along
the nerve fibres, which had the appearance represented in
fig. 5, evidently from the fat of the contents of the fibre
haying been dissolved and deposited again out of the solution
against the walls of the fibre. Before boiling with ether the
nerves had the usual appearance represented in fig. 4. This
proves that mere boiling with ether is not sufficient to remove
all fat, but that subsequent washing with repeated small
portions of hot ether is necessary in order to remove all fatty
matter. The few drops of ether in which the specimen had
been boiled, which were clear when hot, became turbid after
cooling, and under the microscope showed myriads of oil-
globules of a more equal size, and molecules, of which the
globules were being formed. None of the oil-globules depo-
sited from the ether were tinged in any way, and the mus-
cular fibres retained their greenish tinge after boiling, and
preserved unchanged the yellowish or green deposit. This
peculiar degeneration of the heart has been observed by
Wedl (‘Elements of Pathological Histology’ pp. 171, 227),
and by Kolliker, quoted by Wedl. Both call the deposit
pigment, on account of its “ dirty-yellowish” colour, What
relation there exists between this pigment and “ the tapering
groups of small, isolated, yellowish granules,” seen at either
end of the nuclei of the fibres of any healthy heart, as de-
scribed by Mr. Paget (‘ Surgical Pathology,’ vol. i., p. 128),
is a question to be answered by further investigation,

The report on my first specimen given to the Pathological
Society by Drs. Habershon and Bristowe, and printed at
pages 142 and 143 of the ‘ Transactions,’ ‘though admitting
the correctness, on the whole, of my description of the micro-
scopic appearances, is to the effect that the specimen de-
scribed by me does not differ from the ordinary run of cases
of fatty degeneration. The reporters did not find the
molecular deposit greener than the fibres, and the latter pre-

VOL EV. I

114 CASE OF GREEN PIGMENT-

sented so very faint a greenish tinge, that they should have
passed it unnoticed, had not their attention been specially
directed to it. They believe the molecular deposit to be
neither green nor pigment, but simply fat. I believe that this
discrepancy with my account may be explained by the follow-
ing circumstances. The patient died on March 10th; |
made the post mortem examination on March 13th, which
was ona Tuesday. From the day following I had the heart
under examination in a warm room during four successive
days. On Saturday 17th I intended to give an account of the
specimen to the Medical Society of London, but was pre-
vented from doing so, and on that evening the heart went into
the hands of Dr. Routh, who put it in spirits of wine, as it was
already decomposing by that time. Happily I had on that
day exhibited specimens under the microscope to several
friends, all of whom found the molecular deposit to be green,
one of them, Dr. A. Henry, so much so, that he deliberated
with me, what appropriate name could be given to the deposit.
Dr. Gibb recollects to the present moment, that he distinctly
saw a green molecular deposit in the specimen submitted by
me to his inspection. The artist, who made the diagram
which I exhibited to the Pathological Society in illustra-
tion of my paper, coloured it after specimens under the micro-
scope. The eye of this gentleman is perfectly achromatic,
and practised in the minutest distinction of colours. On
the other hand, my microscope is equally achromatic. On
Tuesday, March the 20th, the specimen was, by the kindness
of Dr. Quain, brought before the Pathological Society.

Already, on that evening, I could not succeed in showing the
green colours under the microscope, because, as I then
thought, the light was too yellow and too strong, being con-
densed by Gillet’s apparatus. But I now believe that it was
mainly due to the colour having been changed by decom-
position and extracted by spirits of wine. After the meeting
of the Pathological Society, the specimen, with several others,
was put into strong spirits of wine, and it was only from the
21st downwards, eight days after the post mortem, that the
specimen, in spirits, could be examined by the reporters. I
therefore humbly submit that their report was not based upon
the original appearances, but upon a specimen changed by
the united influences of putrefaction and spirits of wine.

On the 24th I gave to Mr. Brooke, of Keppel Street,
a mounted specimen for examination. He submitted it to
an eminent microscopist, who declared it was nothing which
he had not seen before. I requested Mr. Brooke to look at
it himself, and he kindly did so in my presence, using per-

Powe

DEGENERATION OF THE HEART. 115

fectly white light for illumination, Though in many parts
the green colours had entirely faded, the specimen being
mounted in water, yet Mr. Brooke found clusters of molecular
deposit, the colour of which he declared to be green beyond
any doubt. He was quite positive about that. Even when
he used a second power in the place of an eye-piece, which
arrangement affords an exquisitely high magnifying power, and
with a careful adjustment affords a beautifully clear view of the
object, the colour of the clusters of molecular deposit appeared
to him (and to myself) perfectly green. Two days after
there was only a vestige of the deep-green colour left; it had
decomposed, and dissolved in the fluid surrounding the
specimen.

I have gone to such length, because, if the report of Drs,
Habershon and Bristowe stands unexplained, either my
veracity or the correctness of my sight might be doubted,
and for either I should be very sorry indeed. But happily
there are some witnesses to the green colour of the deposit
before it was decomposed, and to this fact my character and
that of my eye look for protection.

Already, in the note to my paper in the ‘ Transactions’ at
the Pathological Society, I have recorded my opinion on that
degeneration, the produce of which, said to be fat, does not
dissolve in ether. There is no fat, either in the vegetable or
animal kingdon which does not dissolve in ether and volatile
oils (Lehmann, ‘Theoretical Chemistry,’ 3rd edit, p 273.) It
is, therefore, an error to call a deposit fat which does not
dissolve in ether.

Since I saw green pigment for the first time, I have ex-
amined a great number of hearts and found green pigment in
three more instances. In one case where the colour was most
conspicuous, I was afforded a good opportunity of witnessing
how quickly the green colour is changed by decomposition.
It was in June; the heart stood for two days on a plate,
covered by a saucer; on being uncovered it was found to
be in the first stage of putrefaction, viz., smelling badly,
covered with greasy matter and exuding brown serum. The
green pigment was found to have changed its colour into
a dirty earth-brown, and only here and there a faint indication
of the former colour could be distinguished.

I think it only just to say that my paper was read and the
report thereon given, before I was aware or it had been stated
that Wedl and K@lliker mention a similar deposit. Corro-
boration of my observations is accumulating. Rokitansky, at
p- 189 of the new (8rd) edition of his ‘ Pathological Anatomy,’
speaks of granulay pigment deposited in striated muscular

r-3

116 WESTON, ON THE ACTINOPHRYS SOL.

fibre, which is undergoing fatty degeneration. At p. 217
he mentions rusty brown granular pigment in muscular fibrils,
which have lost their striz, and in the atrophied muscles
of a stump after amputation.

I hope to resume the subject in some future number of the
Microscopical Journal.

On the Actinopnrys Sou. By J. Weston, Esq., H.E.I.C.

Havine during the last two or three months met with a plen-
tiful supply of Actinophrys Sol, and foxiunately also a most
unusual deficiency of professional calls upon my time, I have
been enabled to pay these little creatures considerable atten-
tion, not, I hope, quite fruitlessly, since the description I am
about to give of some of their peculiar habits will, I think, be
novel.

I would premise, that as my knowledge of the microscope
is in its infancy (something less than two years old), my ob-
servations will be confined mostly to what I have actually
seen and shown to some of my friends, leaving deductions to
older hands and abler heads.

I regret that I shall have to call in question the correct-
ness of descriptions given by previous writers ; but as I “pin
my faith on no man’s sleeve,” and have rather a method of
looking and thinking for myself, I shall fearlessly state what
the instrument has revealed, much of which differs so mate-
rially from a Paper on the same creature in the 1st volume of
the Journal, that I am led to imagine the writer and myself
have been observing a different species.

In the first place, then, as there appears to be doubt about
the existence of a valvular opening, I have had some thousands
of these animalcules under my observation, and have never
met with a specimen where the valve was absent. It is best
distinguished when about the edge of the seeming dise, and
so far as my observations go, is never still night nor day ; being
slowly, but without cessation, as it were, protruded, occupying
from ten to seventy or eighty seconds in its development, and
then, like the bursting of a vesicle, rapidly and totally sub-
siding ; for an instant it has utterly disappeared, only to be
again as gradually and as certainly reproduced. Should that
side of the creature, where the valve is placed, be turned from
the observer, the effects of the contraction are distinctly seen,
although the valve itself is not, for at the instant of its burst-

WESTON, ON THE ACTINOPHRYS SOL. | i i:

ing and closure, some half-a-dozen or more of the tentacles,
situated on or about it, which have been gradually thrust from
their normal position by the act of its protrusion, now rapidly
approach each other with a jerk-like motion, caused by the
sudden bringing together of their bases.

With one-eighth of an inch objective I have been led to
imagine the valve to be formed of a double layer of the external
hyaloid membrane, the edges of which appear to adhere to
each other tenaciously, notwithstanding the growing distension
from within, until the force becomes so great that the lips, as
they may be called, suddenly separate, apparently to give vent
to some gaseous product, and at this moment there is, as I have
stated, enough seen to induce the belief in the existence of a
double lip-like valve, perhaps the organ of respiration. <A
rough sketch,* Pl. [X., fig. 6 ¢., shows the valve distended.
The power employed was two-thirds objective, and No. 2 eye-
piece of Smith and Beck.

The mode of feeding in the Actinophrys Sol has not, I think,
been accurately given, ‘That the tentacles possess some other
power than that of mere prehension appears to me evident,
because nearly every creature of moderate, and sometimes im-
moderate size, which strikes against them, is at once, for a time,
rendered immovable; when a Rotifer, in crossing the field
with velocity, strikes against an object, the rotatory organ is
frequently seen quickly to suspend its operation, the more
particularly should its cilia strike the cilia of another ani-
malcule; frequently no notice whatever appears to be taken
of the shock, except a sudden change in its course; not so,
however, with the victim to the Actinophrys Sol, on the instant
of contact with whose tentacles it appears paralyzed.

In some cases the prisoner is held for some seconds on the
exact spot where it struck, and then, without any visible means,
becomes attracted towards the body of the A. Sol, gliding
slowly down the tentacle until it is jammed between its base
and a neighbouring one. In another instance (in the same
creature) instead of the prisoner being arrested on or near the
extremity of the tentacle at which it strikes, it is shot down to
the base with extreme rapidity, to occupy the same position
as in the former case. In a third it would seem as if the
appetite of the Actinophrys were sated, or that the prisoner
was not approved of, for after remaining stunned, sometimes
for a few seconds, four or five, sometimes much longer, ciliary
motion (of a Vorticella, for instance) is feebly commenced in-
ternally, not with sufficient energy to produce motion, but, as

* We are unable to obtain the assistance of an artist here, or the
sketches should not have been rough.

118 WESTON, ON THE ACTINOPHRYS SOL.

if a return to vitality were being effected by struggles; shortly
it is seen to glide off the tentacle (as if this appendage pos-
sessed the power both of appropriation and rejection), and
frequently, with but little sign of recovered life, it slowly
floats out of the field.

We have now arrived at the point where the intended food
is fixed, the next process is as follows: from the margin of the
body of the Actinophrys a thin pellucid membrane is pro-
jected, up the side of the creature destined for food, which
proceeds rapidly, but almost imperceptibly, to surround one
side of it; a similar membrane springs sometimes also from
the Actinophrys, but more frequently from the tentacle on its
other side; these amalgamate on the outer surface of the
prisoner, which is thus enclosed in a sac, composed of
what I take to be the extended outer vesicle of the Acti-
nophrys. ‘This vesicle gradually contracts, or rather seems
to return by elasticity to its original position, and the food
thus becomes pressed within the body, there to become
digested,

Often before the engulphing was complete, I have seen the
return of ciliary movement in the victim, which, when large,
exhibits powerful efforts to free itself. This ciliary movement
continues long after its total immersion in the body of its
devourer, and ultimately ceases as its substance seems to be
dissolved.

In no one instance have I ever seen that crossing of the
tentacles described by Kolliker, as one of the means of pre-
venting an escape, but, as I before said, I may have been
watching a different species. In many instances I have seen
half-a-dozen or more prisoners attracted to the tentacles of an
individual, each gradually absorbed, and although thus busily
occupied, no cessation of the action of the valve takes place.
The <Actinophrys itself appears as if possessed of the most
complete stability ; nothing seems to move it, a free Vorti-
cella, almost as large as itself, or a Rotifer of equal dimen-
sions, dashes against it, producing scarcely a sign of motion,
although the force of the concussion would lead one to expect
the little creature would be forcibly driven from its position.
Does this stability arise from its spherical figure, and the hold
thus given to it by the numerous tentacles arising from its
entire periphery ?

Fig. 6 a of the sketch is intended to show a Chetonotus
larus, engulphed ; 6, b,b, three Rotifers fixed between the ten-
tacles; c, the valve. Power used, 2-3rds objective, No. 2
eye-piece.

Fig. 7a represents a large Vorticella, seized and surrounded

WESTON, ON THE ACTINOPHRYS SOL. 119

by the outer membrane, previous to being drawn into the body
as food. Power used 1-8th objective, No. 1 eye-piece.

Fig. 3 is my best drawing with the camera lucida; which, bad
as it is, will, I hope, show, a, a, two Vorticella enclosed within
the vesicle. ‘To obtain this, with my untrained manipulation
of the camera, [ had to raise the stand of the microscope a
foot from the table. The power used was 2-3rds objective,
and No. 2 eye-piece. A very few minutes sufficed to engulph
these larger morsels.

With regard to the reproduction of the species, I can posi-
tively affirm that self-division is one mode, for I may say I
have witnessed it a hundred times, and shown it to others.
The first time it came under my observation was late in the
afternoon, early in the month of August last; division had
commenced before the object came into view, but in less than
an hour it was complete. ‘The observing of this act by a
more experienced microscopist than myself would, I have
little doubt, set at rest the question as to whether or no the
envelope of the Actinophrys Sol was cellular, I watched this
division proceed, as in fig. 4, which was sketched about half
an hour after first seen. First was noticed a deep depression
above and below, not far from the centre of the body ; this, as
it increased, threw the tentacles across each other, in a manner
similar to that described by Kolliker, when in the act of en-
closing an object of prey; this crossing, however, in the act of
self-division would appear to be only the necessary consequence
of the depressions alluded to in the sketch, and the position
into which the outer membrane (in which the tentacles are
inserted) is drawn, As division proceeded, the two animal-
cules steadily, but rather quickly, increased the distance
between them, until the connecting medium was apparently a
long membranous neck, which, to my unpractised eye, ap-
peared composed first of four, then three, then two, irregular
lines of cells (possessing no nuclei), which ultimately dimi-
nished into a single cord, composed of three simple cells,
elongated like the links of a chain, this becoming gradually
more attenuated, until the exact moment of its division could
not be seen, All this latter portion of the process was rather
rapidly performed, that is, from the first formation of the rows
of cells, to the time of what I supposed to be the final separa-
tion, occupied only about a quarter of an hour.

At this time only the margin of each Actinophrys was left
in the field, so rapidly had they receded from each other; so
that, to watch further, I had to shift from one to the other;
this, however, could only be done for avery short time, as they
got out of an easy line of observation, which made it necessary

120 WESTON, ON THE ACTINOPHRYS SOL.

I should confine myself to one, and I selected the larger of
the two. Attached to the side of this I could perceive two
of the cells which had previously formed the connection, and
on the loose edge of the outer was a floating faint line, the
broken thread; this, together with the cells, gradually con-
tracted towards the body, and only a few minutes were neces-
sary to draw the whole into the body of the Actinophrys,
which then appeared as perfect an animal as I had seen.
During the whole of the process, the valve of each, situated
at nearly opposite extremes, was in constant action, and each
creature was busily employed seizing its food.

On the following morning J had several specimens in a
cage, one of which I observed slightly indented on its opposite
sides. I wrote to a microscopic friend to come to my bunga-
low (only about two hundred yards separated from his), but
before despatching the note I took another look, and found
division progressing so rapidly, that I fixed the cage and
carried the instruments to him.

Precisely the same proceedings occurred that I have already
described, except that the connecting chain, previous to sepa-
ration, remained to the last, broader, consisting of five or six
rows of cells. I have since had so many opportunities of
witnessing the same circumstances, that I have written down
self-division in the Actinophrys Sol, as a fact.

That other modes of multiplication occur is, also, I consider,
undoubted, otherwise how are to be accounted for the clusters
of them in their infancy, frequently met with so minute as to
render a } inch necessary to identify them positively ; minute,
however, as they are in this stage, the valve is still to be easily
recognised when the eye has become accustomed to its motion.

With regard to the production of these clusters of young
I have a curious occurrence to register. I have observed, and
that by no means unfrequently, see fig. 5 b, b, a thin pellicle
protruded from the edge of the Actinophrys, sometimes form-
ing a single, large irregular-shaped sac, generally two, as in
the figure, and in one instance, three. The first time this
came under my observation I supposed the cover of the cage
was pressing too hard upon the specimen, and was crushing it,
for shortly both cells simultaneously burst at their outer
margin, giving exit to a considerable mucous discharge,
much resembling (only of less consistence), the discharge seen
on the bursting of pollen; this discharge diffused itself gra-
dually in the water of the cage, and steadily disappeared (in
eight minutes) on dilution. Immediately after the bursting of
these cells I was surprised to see them contract ; this changed
my opinion regarding the supposed pressure of the cover, and

WESTON, ON THE ACTINOPHRYS SOL. 121

I soon became satisfied it was a natural phenomenon, for with
the same slow and steady motion by which all the food is
drawn in, and in the same manner as the connecting medium
of self-division, after separation, so were the burst cells drawn
towards the Actinophrys, ultimately disappearing in its sub-
stance. I kept this creature under the microscope nearly the
whole day, and watched it constantly, feeding it as in all
other cases.

Naturally expectant of a repetition of this proceeding, I
had soon the satisfaction of seeing it (for I had on some occa-
sions thirty or forty specimens in the cage at once), and have
watched the process as I have described upwards of a dozen
times.

Does this emitted fluid contain the germ of future genera-
tions ?

In Buffon’s ‘ Histoire Naturelle’ he says that nature gives
to the Actinophrys Sol a mouth and an anus at opposite sides
of the body. These I have never seen, nor anything that
leads to a conclusion of their existing, for the food is admitted
into the body exactly at the base of the tentacle against which
it strikes ; so also are the excrementitious portions of the food
passed out at any spot where circumstances appear to force
them. ‘This latter process 1 have frequently seen; in one
specimen twice, in less than half an hour, at different spots.

In watching the digestion of a Rotifer, it occurred to me to
see a dark body, composed apparently of the case, remain for
some hours in the same spot, and then gradually approach the
side, as if for expulsion, but while waiting for this to take
place, an opening in another part occurred, and excrement was
voided in quantity ; this voided matter lies amongst the base
of the tentacles, while the opening through which it has passed
closes, and then, with the same stealthy motion I have before
described, it is apparently driven along the tentacles (as if by
repulsion) beyond their extremities, finally disappearing in
the surrounding medium.

I am aware that Pritchard gives the Actinophrys Sol “a flat,
pancake form,” p. 554, but this I look on as an error. If the
cover of the cage in which the specimen is confined be gra-
dually and dexterously raised a little, with a 2-3rd objective,
and No. 2 eye-piece, the animalcule may be made to take
a rolling motion, owing to the imcreased depth of water,
and its spherical form distinctly traced ; moreover, correct
focussing with the higher powers will give the very points of
the tentacles standing erect, which, by focussing down, may be
traced to their bases, while, during the progress, the points

122 WESTON, ON THE ACTINOPHRYS SOL.

and sides of others come plainly into view with the rising of
the globe.

With an 1-8th objective I can distinctly see granules in
constant motion in the body of the Actinophrys, similar to
those always found in the points of the Closterium Lunula.
Apropos to this, a microscopic observer here remarked to me,
a short time since, that these granules, in the hyaline globules
at the points of the C. Lunula, are dependent for their position
in the globule on gravity, being always found, when observed
through the compound body, in the upper portion of the field.
Repeated observations of my own confirm this, which has
not, I think, been hitherto noticed.

In conclusion, I have much to regret that my attempted de-
scription of the actious of the Actinophrys Sol is sadly deficient
in a most essential point, viz., the absence of any measure-
ment of the objects. Microscopists are, as yet, but few and
far between in India, and there is not a micrometer here ;
even the instruments furnished lately by Smith and Beck for the
use of the Government hospitals are deficient in this essential,
added to which is the distressing circumstance, that we are so
far from the manufacturers that what could be procured in
London in a few hours, or at most a few days, [ have been
waiting for with the greatest anxiety since October, 1854, in
which month I sent an order for them.

Sept. 10th. Since writing the above I have had another
case of self-division, which presented some novel circum-
stances.

I had been observing a specimen which was an unusually
large one, when visitors interrupted me. At the end of an
hour or so, on returning to my table, I found that division had
proceeded almost to completion, for the two were each partly
out of the field. I was using Smith and Beck’s } inch. For
a time I observed them to become stationary, which is not
usual at this stage, but I was greatly surprised presently; a
reflex action commenced, and instead of separation, they ra-
pidly approached each other by the contraction or elasticity of
the neck or chain, Not only did they close upon each other,
but the smaller specimen overlapped the larger with full one-
third of its body, and thus they remained still for about two
minutes, giving me hopes I should be able to confirm KGlli-
ker’s description of amalgamation; but here I was disap-
pointed, for again they parted, the same chain appeared to
elongate, and that so rapidly, that in about five minutes they
were perfectly divided, and both out of the field.

Again I followed the larger specimen, because within it

WESTON, ON THE ACTINOPHRYS SOL. 123

could be seen a large green oval substance, approaching to the
outer edge as if for expulsion. This occurred in about half an
hour, but in a manner perfectly distinct from any [ had before
seen. In this case the egg-shaped substance, fully one-fourth
as large as the Actinophrys, was pushed through the integu-
ments, retaining its perfect figure, and giving to the whole
object much of the form of a dumb-bell crystal, only that the
one portion was smaller than the other. Suddenly, as if from
distension, the envelope of the ejected substance burst, the
ovoid figure was instantly dispelled, the greenish matter of
which it consisted spread about similarly to the excrementi-
tious ejections, and quickly disappeared,

Does this remarkable oval figure support the supposition of
the cellular substance of the A. Sol?

In other words, was it a single cell distended with fecal
matter ?

Was the conjunction of the two partially divided specimens
accidental, or had it ought to do with gemmation ?*

* The following letter accompanied the above interesting paper :—

“¢ DEaR Sir, “* Bangalore, Sept. 10, 1855.

“T hope you will find the enclosed worthy a place in the ‘ Journal.’
It strikes me that we are yet in our earliest stages of knowledge of the
Actinophrys Sol. Each specimen I look at shows me something more that
I have seen before, and the difficulty of developing the cause of its motions
appears to me greater the further I go. I have seen a specimen this
morning fixed in a fork of the plant, as it were in an angle, thus forcibly
work itself out ; but by what means I could not distinguish. The valve
was posterior in its progress ; has this anything to do with it when under
such fixed positions ? In this case the body of the Acténophrys was forced
forwards, so as to leave the tentacles as it were trailing behind against the
sides of the angle out of which it forced itself. It has, at the moment
of my writing, been four hours in an open space, feeding voraciously, but
not moving. Indeed, it has not gone beyond the field of the }-inch, since
it took up the position.

“TJ have a curiosity for a future occasion, in the shape of a Rotifer
hitherto unknown, with a forked foot and a tail. I was fortunate in
getting a brother officer to take a better sketch for me than I could do
myself. I fancy it allied to Hydatina,

“¢ Tf I can in any manner be of service in India, I shall be most happy.

“* T remain, dear Sir, very truly yours,
‘* To Dr. Lankester, “¢ J. WEsTON.”
ce. ce.

( 124 5

On the Imprecnation and Germination of Atcx. By M.
PrinesnEim. (Abridged from the Reports of the Berlin
Academy.)

(Continued from page 72.)

Havine thus fully described the mode of origin of what
may be termed the sexual organs in Vaucheria, the author
proceeds to describe the process of impregnation as it takes
place in the Fucacee, and which he finds to be of a precisely
analogous nature. Adverting to Thuret’s observations and
experiments, which showed that unless brought into contact
with the antheridia of the male plant, the spores of these
plants invariably perish without germination, he proceeds to
relate his own researches on the same subject in Fucus vesi-
culosus. 'The result was fully to confirm Thuret’s statements.

The density and opacity of the contents of the so termed
spores in the Fucacee, render them much less fitted for
microscopic examination than are those of Vaucheria, never-
theless the author arrived at some important conclusions.

In Fucus vesiculosus, however, it is not the spore which is
impregnated. ‘The so-termed spore of this plant is a large
thick-walled cell, densely filled with granular contents, and
supported on a unicellular peduncle. When mature the con-
tents of this spore divide into eight segments, which the
author terms ‘ division-spores” (Theilsporen). When arrived
at this stage the contents of the spore are expelled from the
transparent thick spore-membrane, and through the opening
of the conceptacle (Hiillenfrucht). This usually takes place
when the plants have been left dry by the retreat of the tide.
Under the same circumstances the antheridial sacs of the
male plant are also ejected through the opening of the con-
ceptacle.

When the tide returns and the plants are again covered with
water, the antheridia burst exactly as described by Thuret and
Decaisne, and allow the mobile spermatozoids to escape, which
spread themselves in all directions, and reach the “ division-
spores” which have collected themselves around the orifice of
the conceptacles in the female plant. These sporules, which
at the moment of their escape were imbedded in a common
gelatinous matrix (fig. 21), have in the mean while become

IMPREGNATION AND GERMINATION OF ALGAE. 125

isolated by the disappearance of the jelly. It will then be
seen that each sporule is also surrounded by a very thin
colourless gelatinous layer (fig. 22) ; and it will be distinctly
perceived that these eight portions of contents of the original
cell have not as yet acquired any cellulose membrane,

Should any doubt upon this point remain, it will be wholly
dissipated upon close consideration of the two lowermost
sporules in their natural position, and which are the last to
leave the spore-case when its contents escape (fig. 21 a).
These two portions are always produced at the extremity into
a point, which shows the absence of a membrane with the
greater certainty, since the change of form into the spherical,
which these spores undergo when they become isolated, could
not take place did any membrane exist. The spermatozoids,
then, come into contact with these membraneless masses,
covered only with a thin gelatinous layer. It is these masses,
the “ division-spores” of the Fucus, which after impregnation
has been effected become the young plant. The first indica-
tion of commencing germination in them is the formation of
a visible, tough membrane (fig. 23) around them, which also
manifestly arises from a transformation of the gelatinous layer
in which they are enveloped. The membrane is apparent about
twenty-four hours after the contact with the spermatozoids.

So soon as the membrane is formed around the sporules, a
number of minute red-brown nuclear bodies, which did not
exist before, are visible at the periphery of the sporule, and
they are enclosed together with the mass of the sporule by the
newly-formed membrane with whose inner surface they are in
contact. ‘The author never failed to observe these minute,
red-brown nuclei (fig. 23), in impregnated sporules which
afterwards grew up into young plants. They make their first
appearance almost simultaneously with the formation of the
membrane at the periphery of the sporule, and do not dis-
appear till afterwards, and in the further development of the
impregnated sporule (fig. 24). The author looks upon these
corpuscles, whose colour corresponds with that of the nuclei
of the spermatozoids of Fucus, as originating in the sperma-
tozoids.

The present case, therefore, he remarks, affords another
instance of what was observed in Vaucheria, viz., that the act
of impregnation does not consist in the operation of the sper-
matozoids upon a previously perfectly-formed cell possessing a
membrane—an ‘‘embryonic cell”—which would be impreg-
nated through its membrane, but rather in this, that one or
several spermatozoids enter a still membraneless, granular
mass, which afterwards, together with the spermatozoids,

126 PRINGSHEIM, ON THE IMPREGNATION

acquires a membrane, and thus comes to represent the vege-
table embryonic cell capable of immediate development.

The parent-spore in Fucus and the sporangium in Vaucheria,
are morphologically equivalent to the central cell of the arche-
gonium in Ferns and Mosses, to which the canal of that organ
leads, and to the embryo-sac of phanerogamous plants. The
author has hitherto in vain sought for an embryonic cell before
impregnation has taken place, in the central cell of the arche-
gonia. But, on the contrary, is pretty well convinced that in
this case also the true embryonic cell is not formed around a
portion of the contents of the central cell until after the en-
trance of the spermatozoids, and that it encloses the sperma-
tozoids which have thus effected their entrance. May not
the same process take place also in phanerogamous plants ?
May not the point of the pollen-tube which enters the embryo-
sac enclose the spermatozoids, which together with the contents
of the embryo-sac become the cell of the embryo, which is not
developed until after impregnation ?

After noticing the obvious analogies, thus indicated, between
the process of impregnation and the probable mode of origin
of the first embryonic cell in animals and plants, the author
goes on to speak of the sexual organs in the Floridee.

He says that his own observations, which fully agree with
those of Thuret, Mettenius, Derbes, and Solier, show that
N&geli was in error in stating that the antheridia, or cells so
termed in the Floridee, contained spiral filaments. These
organs, however, are nevertheless true antheridia, and the
absence of spiral filaments in them only show what was evident
in Fucus and Vaucheria, that the existence of spiral filaments
can no longer be regarded as the sole morphological proof of
the male function of an organ. On the contrary, it is indis-
putable that there are several forms of self-moving corpuscles
which, in plants, exercise the function of spermatozoa.

Besides the spermatozoids of the Ferns, Mosses, Characee,
&e., which approach in conformation the animal spermatoza,
we are at present also acquainted with forms more nearly
approaching zoospores, as in the Fucacee ; and, lastly, with
that, differing from either, peculiar to the spermatozoids of
Vaucheria, whose nearest allies would perhaps be met with
among the Lichens. But the cells of the so-termed antheridia
of the Floridee, manifestly resemble in the most striking
manner the spermatozoids of the Fucacee, and still more those
discovered by the author in Sphacelaria, which, in their struc-
ture, appear to constitute an intermediate form between the
two. This correspondence in structure, renders it in the
highest degree probable that these organs constitute the true

AND GERMINATION OF ALGZE. I?

male sexual apparatus of the Floridee, although they possess
so little motile power. As far as regards the antheridian
cells of Polysiphonia, the author can only confirm what is
stated by Thuret. “1 noticed,” he says, ‘it is true, a gradual
emptying of the originally full antheridia ; but I observed the
isolated antheridian cells close to the antheridium from which
they had escaped, free indeed, though always motionless.”
Like Thuret and Mettenius, the author has never been able
to perceive the cilia described by Derbes and Solier.

Another question equally important with the discovery of
the antheridia, concerns the existence of organs in the Floridee
which are impregnated by the antheridea, whose existence has been
thus certainly proved.

The author has been unable to solve this question, which
he proposes as a very interesting subject for botanists residing
constantly at the sea-side. He has endeayoured, however, by
observation of the germination of tetraspores, and of the con-
ceptacular spores of Ceramium rubrum, to approach its so-
lution.

But few observations upon the germination of the Floridee
have been published, and an essential defect pervades the few
that have been made, owing to the circumstance that observers
have been satisfied with the development of a few cells from
the spore, and have not sought to inquire whether the growth
proceeding from the spore resembles the parent plant or not.
In order to determine this point, those plants are undoubtedly
the most favourable whose laws of growth are known, and the
author therefore instituted his researches on the spores of the
species of Ceramium, because he had investigated the forma-
tion of the stem of the Ceramia with the accuracy requisite
for an inquiry of the kind. For this purpose, it is sufficient
to know, with respect to the mode of development of the
Ceramia, that they grow with a terminal cell, from whose
continued horizontal division the separate joints arise ; and
that the first cells of the so-termed cortical layer arise from
the formation of oblique walls which are developed in the
cells constituting the joints, in a direction from above and
inwards, downwards and outwards; these first cortical cells
then subdivide repeatedly, and thus constitute the cortical
tissue surrounding the central series of cells.

Now, the tetraspore of the Ceramium in its germination,
follows the mode just pointed out, from its first division
onwards. It is itself the first apical cell of the future plant, as
is shown by its longitudinal multiplication in the same way
as the other apical cells, and in the indications of the forma-
tion of the cortical cells in the mode above described. The

128 PRINGSHEIM, ON THE IMPREGNATION

product of its germination is therefore indubitably a young
Ceramium.

But it is otherwise with the conceptacular spore. From
this arises a very irregular cellular growth, which in form and
mode of origin, exhibits no similarity whatever with the body
of the Ceramium.

From this conceptacular spore is manifestly produced a
prothallus (Vorkeim), and it only remains to inquire whether
this production is equivalent to the prothalli of Mosses or to
the prothallium of Ferns. As the author has often seen the
commencement of germination in the still closed conceptacular
fruit of the Ceramia, without noticing any entrance into it, it
appears to him not improbable that the impregnation of the
Floridee takes place in the prothallus arising from the concep-
tacular spore ; unless it may be, that the Floridee with closed
conceptacular fruit, may behave differently in this respect from
those whose conceptacles have a canal leading into the in-
terior.

Though his researches have been very incomplete, he sees
reason to believe [with Harvey and Thwaites], that the tetra-
spores of the Floridee represent only gemmules of the sexual
multiplication, whilst the conceptacular spores are either the
true female sexual organs of those plants, or at any rate pro-
duce a structure which exercises the female sexual function in
some way or another.

Among the Fucoidee of Agardh, the existence of antheridia
in the true Fucacee (Angiospermee, Kiitzing) is no longer an
isolated fact. A second instance of antheridia filled with
mobile spermatozoids, in structure and mode of development
far more closely resembling the antheridia of Fucus than those
observed by Thuret in Cutleria, was discovered by the author
two years since in Sphacelaria tribuloides.

The terminal cell of Sphacelaria, which, during the youth
of the branch as a vegetative organ, forms the joints by re-
peated horizontal division, when the branch has attained to a
certain age, suddenly ceases to divide; it enlarges consider-
ably, and constitutes the organ, closely filled with contents at
the apex of the older branches, and which has been termed
by algologists the sphacela. This sphacela, which is always
terminal, is in fact nothing more than the enlarged terminal
cell of the ramule. It is precisely the same also with the ter-
minal cells of those peculiarly metamorphosed lateral ramules,
which are known as the propagative buds (brutknospen) of
the Sphacelaria, and which are capable of becoming new plants
by direct growth. Within this transformed cell on the com-
mon branches, as well as on the propagative buds, are after-

AND GERMINATION OF ALG. 129

wards formed one or several large cells, which do not usually
include the whole contents of the sphacela. These cells are
the antheridia of the Sphacelaria, and their contents, at first
brown, gradually lose all colour and appear indistinctly orga-
nized, assuming the aspect of a fine-granular, mucoid sub-
stance, obscurely subdivided into separate, roundish, colourless
corpuscles, and closely resembling the contents of the anthe-
ridium of a Moss previous to its opening.

Shortly after the antheridium has reached this stage of
development, its membrane is suddenly protruded on one side
into a long tubular prolongation, which breaks through the
wall of the sphacela (fig. 25) and opens at the point. At the
same time an active struggling and swarming movement in
the contents of the antheridium begins to take place under the
eye of the observer; and it is seen that the indistinct organi-
zation presented in the contents of the unopened antheridism,
was due to the existence of closely-packed, minute, colourless
corpuscles, crowded into the narrow space.

Most of these corpuscles quickly escape, and quite iso-~
lated from each other, through the tubular process, moving
spontaneously and freely with great rapidity in all directions.
Those left in the antheridium now having more space, exhibit
a distinct locomotion, although less rapid than that of the
corpuscles which have made their exit.

In the spermatozoids left within the antheridium, the author
has observed motion for more than an hour, whilst the escaped
spermatozoids cease to move after a few minutes.

The movement of the spermatozoids, though in some
degree like that of zoospores, appears to differ in this respect,
that the motion of zoospores is more uniform and continuous,
and that of the spermatozoids interrupted and jumping.

The spermatozoids of Sphacelaria appear like very minute,
clear cells without any dark or coloured nucleus, and so far
present the most striking resemblance to the antheridian-cells
of the Floridee ; but, on the other hand, they are furnished
with two cilia, like the spermatozoids of the Fucacea, like
which they move very actively. They appear, therefore, to
constitute an intermediate form between the spermatozoids of
the Fucacee and those of the Floridee, though as regards the
development of the antheridia within a single cell, and the
mode in which the antheridium opens, they are manifestly
more nearly allied to the former.

The author has little hesitation in assigning the female sex
to those plants which bear lateral sessile spores, but does not
seem to have confirmed this by direct observation. He re-
marks that it is very probable that Sphacelaria tribulvides alse

VOL. IV. kK

130 PRINGSHEIM, ON THE IMPREGNATION

affords zoospores, which escape from the cells forming the
joints; but of this also he does not appear to have any certain
proof, He describes antheridia, precisely like those of Spha-
celaria and developed in the same way, in the terminal cells
of the lateral ramules in the closely-allied Cladostephus
spongiosus.

With respect to the fresh-water Algee most nearly allied to
Vaucheria, it is, perhaps, sufficiently clear from the author’s
observations on that species, that these plants, besides the
asexual, gemmate multiplication by zoospores, also present
a true sexual propagation. The most probable supposition
would be that the female organs of these plants, as in
Vaucheria are to be sought in the quiescent-spores, which have
been found in many genera. But in the next place it remains,
not only to discover the antheridia in these plants, but also to
show the possibility of the entrance of the spermatozoids into
the interior of the quiescent spores, through an opening in the
spore-membrane ; or as in the Fucacee the impregnation of the
sporules externally to the parent body.

The author’s observations on these points, though incom-
plete, may still be serviceable towards further research.

The asexual multiplication of Achlya prolifera is well
known, but besides the zoospores this plant also presents
quiescent spores contained in peculiarly shaped sporangia.

The author finds that these spores germinate in the same
way as do those of Vaucheria. He found also that before the
formation of the quiescent spores, and in some measure
simultaneously with the division of the contents into the
masses destined to become quiescent spores, a great many
minute, oval, sharply-defined openings are formed by the
absorption of the cell-wall of the sporangiwm in several places,
which constitute so many open passages into the interior of
the sporangium even whilst its contents are in progress of
formation into quiescent spores. ‘The object of these openings
is clearly to allow of the entrance of the spermatozoids into
the dividing spore-mass. In this case, also, the action of the
spermatozoids must be exerted upon the contents of the
sporangium whilst undergoing division and not upon perfectly-

formed spores, for, long after the openings have been formed,
the segments of contents of the sporangium, are not even
separated, and far less do they represent fully-formed cells.

This process of development indicates a great similarity
between Vaucheriu and Achlya ; but whilst in the summit of
the tube in Vaucheria a single large zoospore is formed, in
that of Achlya very many smaller zoospores are produced, and
the same is the case with respect to the quiescent spores ;

AND GERMINATION OF ALG. 131

whilst in the sporangium of Vaucheria only a single, large
quiescent spore is produced which is impregnated through a
solitary orifice in the membrane of the sporangium, in the
sporangia of Achlya numerous smaller quiescent spores arise,
and the supposed impregnation takes place through numerous
openings in the membrane of the syorangium, whose number
probably corresponds with that of the spores. The analogy
between the two cases is further rendered more apparent by
the existence of very slender ramifying branches springing
from the parent tube in close contiguity to the sporangium
containing the quiescent spores, and which are so closely
applied to the membrane of the latter as apparently to be
adnate to it. ‘lhe analogy between these ramules which were
first pointed out by Braun, and the ‘ hornlet” in Vaucheria
cannot be overlooked. ‘The author has often noticed them, and
it has appeared to him that where they were in contact with the
membrane of the sporangium, these ramules throw out short
papillary lateral shcots, which were protruded through the
openings of the membrane of the sporangium and caused the
close adhesion of the ramules to that body,

Although, at present, it is but a mere supposition that the
spermatozoids of Achlya are developed in these armules, the
existence of the openings through which the spermatozoids
may reach and impregnate the contents of the sporangium,
has at least been discovered; and it has also been shown that
the quiescent spores of Achlya germinate in the same way as
do those of Vaucheria.

Among other fresh-water Alge which, besides the asexual
mode of multiplication by zoospores, also present quiescent
spores ; the author proceeds to communicate some observa-
tions, made upon CUdogonium, Bulbochate, and Coleochete.
With respect to the micropyle of the sporangia in Gedogonium.
he remarks that before the formation of the spore in the parent
cell, a great accumulation of its contents takes place as in
Vaucheria ; and on many occasions in Gtdogonium tumidulum,
he has witnessed the sudden rupture of the membrane of the
sporangium, on one side, through which the granulous and
cutaneous layers are protruded (fig. 26.) But the latter does
not, as in Vaucheria, throw off a portion, but is again with-
drawn ; and the whole contents of the cell, not yet surrounded
by a membrane, are converted into the well-known quiescent
spore of CEdogonium, most probably with the co-operation of
spermatozoids which have entered through the opening in
the sporangium thus formed, The opening in Gvdogonium is

3005.

132 PRINGSHEIM, ON THE IMPREGNATION

smaller than in Vaucheria, and it represents an oval, sharply-
defined slit (fig. 27).

The passage for the spermatozoids into the parent-cell of
the quiescent spore of Bulbochete is formed in a different
way ; in this instance the membrane of the sporangium, like-
wise in consequence of the accumulation of its contents, is
also ruptured ; but in a transverse fissure, more or less above
the middle (figs. 28, 29), so that the membrane is split into
two perfectly separate parts, between which the open passage
to the contents of the sporangium is rendered possible.

The openings of the sporangia in G¢dogonium, and the trans-
verse fissures of those in Bulbochete, both of which afford an
open passage into the interior of the sporangium, being thus
made known, a phenomenon common to both plants demands
the closest consideration.

Besides zoospores and quiescent spores, a third kind of
spores are met with in these plants, which are formed in
smaller cells, widely different from the common yegetative
cells (fig. 30a). To this kind of spore A. Braun has applied
the name of ‘“ microgonidia,”’ noticing, at the same time,
that the product of their germination is merely very minute,
usually bicellular little plants. These microgonidia, which
present precisely the same structure as the zoospores, always
affix themselves in a remarkable way, either upon the
sporangium or close to it. In Cdogonium they are found
seated sometimes upon the membrane of the sporangium, some-
times upon that of the cell immediately contiguous to it, and
in Bulbochete invariably upon the sporangium (figs. 28, 29, 30).
Hence they open, either at once or after they have pushed
out one or two short cells, and pour out their contents.
Although, at present, no indication of spermatozoids has
been observed in them, still the remarkable concurrence of
the evacuation of these maicrogonidia, immediately over, or
at any rate very close to the opening of the sporangium in
(Edogonium and of the transverse jissures in Bulbochete
necessarily leads to the supposition that the contents of the
microgonidia penetrate into the sporangia, and the author
has no doubt that it will be found that the impregnating
morphological elements of Cdogonium and Bulbochete
exist in the little plants produced from the microgonidia.
But this impregnation in Bulbochete and Gedogonium differs
essentially from that which is observed in Vaueheria, for in
the former case the two kinds of sexual organs are not pro-
duced upon the fully developed plants, but a special struc-
ture, a prothallus as it were, simply bearing antheridia is

AND GERMINATION OF ALG. 133

formed, to act the part of an impregnating apparatus. And
connected with this supposed diversity in the mode of im-
pregnation is probably the difference observable in the mode
of germination; for the germination of the quiescent spores in
Bulbochete differs very essentially from that of spores of
Vaucheria.

The curious development of the quiescent spores of the
former plant is thus described by the author.

The thick-walled, wholly red spore became green at the
border, the innermost layer of the cell-wall expanded and
burst through the outer layers and the membrane of the spo-
rangium. ‘Thus the spore escaped from the sporangium covered
only by the innermost thin layer of the cell-wall, whilst the
ruptured walls either opened out like two lids (fig. 31), or the
upper portion was elevated upon the escaping spore (fig. 30).
This liberated cell in a few hours was elongated into an ovoid
corpuscle (figs. 32, 33), whose contents shortly afterwards
were divided by successive scissions into four parts, lying one
behind the other (fig. 33).

In one or other of these portions of contents might now be
perceived a lateral, clear space (fig. 33), whilst the membrane
surrounding the four bodies thus constituted became more and
more expanded, lost its consistence, and swelled out into a
kind of jelly. At the same time a faint movement was per-
ceptible in the four reddish-qgreen bodies, becoming more and
more marked as the membrane expanded. The structure of
the bodies was now sufficiently obvious; each exhibited a
clear space at one end, around which was a crown of cilia
(fig. 34); they moved about as far as the space would allow
with great activity, with a continued vibration of the cilia, and
an uninterrupted turning on their axis.

Thus in the interior of the quiescent spore four zoospores
were produced, which presented precisely the same structure,
and were of the same size as the usual zoospores of Bulbochete,
from which they differed merely in the circumstance that they
contained, at any rate some of them, a red oil, similar to that
with which the quiescent spores are filled.

These zoospores, when liberated from the surrounding
vesicle, attached themselves and germinated. This production
of four zoospores within the quiescent spore of Bulbochete,
recalls the similar process in Chlamidococcus pluvialis, and
shows that the quiescent forms of the Volvocine should be
regarded simply as quiescent algan spores resulting from
sexual impregnation.

In various species of Coleochete the formation of zoospores,

134 PRINGSHEIM, ON THE IMPREGNATION

from the contents of the quiescent spore, may be observed to
take place in pretty nearly the same way as in Bulbochete.

Thus it will be seen that two modes of development of
quiescent algan spores, resulting from impregnation, exist.
Whilst in one mode, that which obtains in Vaucheria and
Achlya, the quiescent spore is developed at once into a young
plant; in the other, Bulbochete, Coleochete, Gedogonium, it is
merely the parent of swarming zoospores, which grow into
young plants by direct germination.

That similar sexual conditions occur in the Palmellacee is
almost certain; at any rate, in them also the existence of red,
quiescent spores together with zoospores is indubitable. Thus
in Gleocapsa ampla the author found, besides the individuals
whose cells become zoospores, other cells which acquire thick
walls, and become filled with red contents. These forms
have been erroneously regarded as distinct species. They are
in fact the female individuals of the plant.

Researches are still very much wanted as to the sexual con-
ditions of other Alga, such as the Spirogyre and Desmidiacee
on the one hand, and the Oscillarina, Kutz. on the other, in
which nothing like antheridia have been observed, although
the author indicates the basilar cells in Rivularia as showing
some indications of such being their nature. In conclusion,
he thus sums up the result to which he conceives his observa-
tions have led :—

1. That the phenomena presented in Vaucheria and
Fucus, establish beyond doubt the material co-operation
of the spermatozoids in the act of impregnation.

2. With respect to the essential nature of the act of
impregnation ; it appears that the spermatozoids do not
impregnate an already perfectly formed cell, but that the
act of impregnation consists in this, that cne or several
spermatozoids enter the, as yet, membraneless contents
of a cell; that this amorphous substance is not sur-
rounded with a membrane until after the entrance of the
spermatozoids, which membrane at the same time en-
closes the spermatozoids that have effected an entrance.
The true embryonic vesicle, therefore, does not exist
before impregnation, but is formed subsequently to that
act.

3. With respect to the conditions attending the fructifi-
cation of the Alg@; that a sexual propagation takes
place in them as well as an asexual multiplication or
gemmation,

The asexual multiplication is effected by means of the

AND GERMINATION OF ALG. 135

tetraspores in the Floridee, by the prolifications and propaga-
tive gemmules which are found in the Fucacee and the other
Fucoidee, and by the zoospores which are widely distributed
among the marine and fresh-water Alge. The sexual function
is probably fulfilled in the Floridee by the cells of the anthe-
ridia and the conceptacular spores; in the Fucacee certainly
by the spermatozoids and the contents of the so-termed
“ spores ;’ in the Conferve by spermatozoids and the contents
of the quiescent spores.

The spores of the Fucoidee and the quiescent spores of the
fresh water Alge, however, are properly spore-fruits (spo-
rangia), whose contents are fertilized sometimes within, some-
times without the sporangium.

The Alge, moreover, are sometimes di@cious—and this is
the case with the greater number—some monecious. The
individuals, lastly, which form the asexual organs of multipli-
cation are usually sexually sterile; but at the same time in
their vegetative parts more strongly developed than the fertile ;
this holds good both of the individuals with tetraspores among
the Floridew, as well as of the individuals of the fresh-water
Alge, which form zoospores. ‘lhe latter condition, which has
as yet not been noticed, promises to afford much aid in the
classification of allied forms.

On the Course of the AMytotp Deceneration. By Rupotpx
Vircnow. (Abstracted from the Archiv. f. Patholog. Ana-
tomie und Physiologie. Bd. viii., p. 364.)

In former communications on the subject of “amyloid degene-
ration” the Author was able to adduce, as instances of the
affection, besides the corpora amylacea in the nervous system,
only the waxy degeneration of the spleen, liver, and kidneys ;
but since then some more recent cases have afforded him the
opportunity of extending his researches, and of making, as he
thinks, a very important advance in the knowledge of the
remarkable changes included under the term.

In all these cases there existed chronic, and very consider-
able disease in some part of the osseous system. Even in his
former communication, respecting the ‘ waxy spleen,” he had
noticed that it was especially in persons affected with chronic
disease of the bones that this form of degeneration of the
organ was presented, and he has since seen scarcely a single
case in which the same complication did not exist. This
frequent association cannot, he thinks, be explained except
upon the supposition that the disease in the bone exerts a

136 VIRCHOW, ON THE COURSE .

determinate influence upon the production of the affection in
the spleen, liver, and kidneys. It is usually the case that
primary, long-continued disease of the bones, especially caries
and necrosis of the larger bones or portions of the skeleton,
in their subsequent course, induce cachexia and dropsy, and
par ticularly albuminuria and degeneration of the kidneys, but
how is the connexion between the primary and secondary
affections to be explained? ‘wo hypotheses, with respect to
this, might be entertained, either the disease in the osseous
system may so far interfere with the general nutrition that the
constituent elements of the spleen, kidneys, and liver may be
deprived of their normal supply of nutriment, and disposed to
undergo the amyloid change, or the disease in the bones may
actually produce the amyloid matter, which is deposited
secondarily in the other organs, In the former case there
would be a peculiar metamorphosis, an idiopathic, morbid
change in the elements of the spleen, liver, and kidneys; and
in the second an instance of metastasis, in which the glandular
organs would be merely the seat of the deposition of the
morbid material.

Hitherto Virchow has not found in the bone itself a sub-
stance corresponding to that which occurs in the abdominal
glands, whilst he has always detected its presence in the car-
tilages. In an aged individual, who presented in many of the
joints the changes peculiar to eau arthritis, the pubic sym-
physis in particular, towards the interior aspect, was much
enlarged, and unusually moveable. When cut across, there
was apparent in the middle of it an irregular, vertical fissure,
with uneven, somewhat tuberous walls, and without any fluid
contents. The layers of cartilage on each side were consider-
ably thickened, of a dirty, yellowish colour, and very unequal
density ; the parts immediately contiguous to the fissure were
more especially softened in places, greasy, and as it were,
broken up, so that portions, of considerable size, were almost
separated from the rest, or were held together only by slender
connexions. Microscopic examination disclosed a great variety
of constituents. ‘The cartilage cells were generally enlarged,
their capsules very thick and wide; in many places caidas
able-sized groups of them might be observed in a proliferous
state, but in some might also be seen minute, roundish, or
flattened corpuscles. Towards the surface of the fissure many
cartilage cells were in a state of fatty degeneration, the matrix
being, at the same time, transformed into a soft, clouded,
streaked, and granular substance, in which the presence of
cholesterin was here and there perceptible. In these situa-
tions the condition might be described as ‘ atheromatous dege-

OF THE AMYLOID DEGENERATION. 137

neration,’ similar to that which takes place in the arteries.
Crystalline cholesterin existed only on the surface, beneath
which, however, the matrix presented numerous alterations ;
isolated portions were composed, in great part, of the un-
changed, hyaline, dense substance, close to which might be
noticed considerable tracts and masses in which the matrix
was streaky and fibrous. ‘The fibres in some parts resembled
the rigid filaments in the well-known asbestos-like portions of
the costal cartilages, and in others assumed more the aspect of
hard, wavy, and strongly refractive strie. On the addition of
solutions of iodine, either the simply aqueous, or made with
iodide of potassium, some portions of the microscopic section
at once assumed an intense reddish-yellow (iodine-red) colour,
whilst others remained perfectly clear and colourless; the
greater part presented a yellowish, and, on more prolonged
action of the reagent, a yellowish-brown hue. If sulphuric
acid or chloride of zinc be now added, the reddish-yellow
spots are immediately rendered of a violet, or occasionally,
bright blue colour, although a strong seddigh tinge is always
retained. Under the action of a very conc entrated solution of
iodine, also, the colour becomes at once dark red, or nearly
violet-red, especially when the section so treated is dried and
again moistened with water. The places in the section where
the iodine reaction took place might be very distinctly recog-
nized, even by the naked eye, as dark, reddish, or blackish-red
points, particularly when thin sections were viewed over a
clean, white surface. When examined with the microscope it
was readily seen that it was not cholesterin in any form which
afforded the simple reaction with iodine; as is usual, this
substance, even after the addition of iodine, remained colour-
less, and did not exhibit any of the often-noticed changes of
colour, except under the energetic action of sulphuric acid or
of chloride of zinc.

It was now a point of much interest to determine in which
of the structural elements the reaction took place ; with respect
to which it was at once evident that both the matrix-substance
and the corpuscles participated in it, either each singly, or
both, though less extensively, conjointly. Of the corpuscles,
again, it was quite evident that it was the thick capsules which
afforded the deepest colouring, which was intense in proportion
as the corpuscles were of larger size, and more free in the
surrounding matrix ; but in some places the true cell (contents
of the capsules) also appeared to be similarly affected ; and,
especially in the smaller ones, Virchow often noticed the entire
corpuscles coloured red or violet throughout.

It was remarkable that no microscopic characters could be

138 VIRCHOW, ON THE COURSE

discerned, from which it might be concluded a priori whether
the parts would be acted upon by the iodine or not; neither
in the matrix, nor in corpuscles, did the spots, which were
afterwards coloured, exhibit before the addition of the iodine,
any difference from those which remained uncoloured ; nor,
excepting the rather remarkable microscopical condition of the
whole cartilage, could it be said that these cartilages presented
any appearance by which they could be distinguished from
many other senile cartilages in which the reaction did not
occur. This circumstance, with regard to the cartilages, is
perhaps of the more importance to be noted, as a strong con-
trast in this respect was presented in other parts, and espe-
cially in the glandular organs, in all of which, especially in
more advanced stages of the affection, in the portiens where the
amyloid change had taken place, a degree of softening inde-
pendent of any reagent might be recognised, and particularly
the presence of a brilliant, pale, thickening substance.

A farther step in advance was made on the inspection of the
body of a boy aged 13 years, who had died of albuminuria and
dropsy, following spondylarthrocasis. In this case there
existed almost complete destruction of the imtervertebral sub-
stance between the last lumbar vertebra and sacrum, together
with caries of the contiguous bodies of the vertebre, and ex-
tensive sinuses passing through the sciatic notch and over the
crista whi, running far between the muscles of the buttock
and thigh which were in a state of fatty degeneration, and
opening externally by large fistulous orifices. No tubercles
existed in any part, not even in the lungs; a single gland in
the mediastinum only was enlarged, and filled with a cheesy,
necrotic matter. On the other hand, there was very far ad-
vanced parenchymatous nephritis, with amyloid degeneration
of the glomeruli, sago-spleen, and slight enlargement of the
liver, whose cells, close to the portal vessels, were filled with
fat, whilst the interior of the acin? was occupied with amyloid
substance. All the waxy parts of the spleen, liver, and kid-
neys afforded, with iodine alone, a distinct reaction, obvious
even to the naked eye, and on the addition of sulphuric acid,
a beautiful violet and blue colour,

The condition ef the lumbar glands was especially worthy
of attention. ‘They were much enlarged, and presented exter-
nally a peculiar bluish-green, transparent aspect. On section,
the medullary substance (Aidus) appeared unchanged, whilst
the cortical portion was more or less completely transformed
into a clear, anaemic, transparent, nearly colourless gelatiniform
substance. This condition was most apparent in the glands
situated nearest to the diseased portion of the spine, and in

OF THE AMYLOID DEGENERATION. 139

these it extended almost through the entire thickness of the
cortical substance. Higher up the alteration was more con-
fined to the peripheral portions of the glands in which the
afferent lymphatics open, the substance surrounding the hilus
and the inner portion of the cortical substance retaining their
normal aspect. It could be readily perceived even with the
naked eye, but still better with a lens, that the substance was
not uniformly affected, but that the change had taken place in
the points, which in a normal lymphatic gland, are visible as
white, round, vesicular spots—the follicles or alveolt.

Microscopic examination entirely confirmed this supposi-
tion, and the chemical reaction fully established the identity
of this morbid condition of the lymphatic glands with that
formerly described by the Author under the term sago-spleen.
In the lymphatic glands, as in the spleen, the follicles appear
to constitute the proper seat of the affection, and in the one
case, as in the other, the proper gland-cells (lymph-corpuscles)
are destroyed in proportion to the amount in which the new
substance is deposited. The follicles or alveoli enlarge at the
same time, so as to attain to the size of a small pin’s head,
although the enlargement is never so considerable as in the
splenic follicles. ‘The deposited substance consists of com-
paratively large (0:04—0-05™™"), rounded, or subangular cor-
puscles, of a pale, colourless, homogeneous aspect, and breaking
up under pressure in such a way that their solid structure is
plainly discernible. In many cases might be perceived minute,
superficial depressions, rounded or stelliform, and usually one
or two in number, in which a minute, nucleiform body was
often seen lying. Amongst them was spread a fine network,
composed of stellate elements, in the nodular points of which
1—2 manifest nuclei were usually contained. Even on the
simple addition of iodine the pale corpuscles assumed a beau-
tiful yellowish-red colour, and on the application of a solution
of iodine in hydriodate of potass, they were rendered distinctly
bluish-red, which, on the subsequent addition of sulphuric
acid, or of ioduretted chloride of zinc, became the most
beautiful violet, gradually passing into a deep blue.

This degeneration, however, was not confined solely to the
follicular elements, it being evident that the fine arterial
vessels of the interstitial tissue had undergone a similar
change in their tunics. They were thickened, and the lumen
was contracted; whilst the walls, which appeared shining
and almost homogeneous, afforded the most marked reaction.
This change in the vessels, however, was also confined to the
proper cortical substance of the gland; neither in the medul-
lary substance, nor externally to the gland, was anything of

140 VIRCHOW, ON THE COURSE

the kind observable in the blood- or lymphatic vessels. Nor
in the interior of the gland did the vascular plexus there
situated present any colouring.

This discovery is of considerable importance as regards the
development of the corpora amylacea. On comparison with
the figures given by Kolliker (‘ Mik. Anat.’ ii. 2, figs. 365-
367) of the normal lymphatic glands, it will be satisfactorily
seen that each individual amyloid granule corresponds, not
with a single cell, but with an entire group. For since the
fine net-work remains in the interior of the alveoli, and, speak-
ing generally, only one corpus amylaceum lies in each areola,
it is obvious that it must represent an entire mass of the pre-
existing cells. In this case, also, the amyloid degeneration
cannot be regarded as a simple transformation of individual
cells; as in the arterial vessels all parts of the wall—
connective tissue, and muscular fibres—are ultimately fused
into a homogeneous substance, so is it with the cells in the
lymphatic follicles.

The morbid condition in the case last cited extended very
widely upwards. The epigastric lymphatic glands were also
extensively implicated, and on close examination some of the
bronchial glands also exhibited scattered waxy spots, though
it must be confessed to a very limited extent. At first it
appeared as if the process in the blood-vascular system was
limited to the minute arterioles of the lymphatic glands,
spleen, and kidneys; but it was afterwards found that the
arterial vessels of the digestive tract were also largely im-
plicated.

Dr. Jochmann was the first to notice that a strong iodine
reaction was manifested in the gastric mucous membrane, and
further investigation proved that this commenced in the
vessels, and was always most strongly marked in them.
Further research showed the same alteration in the vessels of
the mucous membrane of the cesophagus, and of the whole
intestinal canal, but particularly in the small intestine. It
was limited in all parts to the fine arterial vessels of the
mucous membrane, or at most involved only those of the
uppermost layer of the submucous tissue, and it might be
traced to some distance into the arterial side of the capillaries.
Without re-agents, little appearance of change was discernible,
the only indication of it consisting in the circumstance that
the walls were slightly thickened and homogeneous; on the
application of iodine and sulphuric acid, however, a very
deep, dark-violet colour was manifested, which never passed
into such a beautiful blue as that presented in the lymphatic
glands, but was nevertheless very characteristic. Simple

OF THE AMYLOID DEGENERATION. 141

iodine even, also produced a yery strong colouring. The
change to the naked eye was not very striking. The mucous
membrane in all these parts had a very pale aspect; and in
the stomach and cesophagus it was somewhat thickened, un-
usually transparent, and in parts of almost gelatinous con-
sistence.

The above case indicated a much wider range of the amy-
loid degeneration than was previously known, and another
observation showed the reliance which might be placed upon
the truth of the discovery. A man, thirty years of age, who
had long suffered from necrosis of the femur, with sinuous
abscesses and fistulous openings, died, also, with albu-
minuria and ascites, but not until a subcutaneous abscess of
the scrotum, suppurative inflammation of the parotid, and
hemorrhagic pleurisy had taken place. There was found an en-
larged waxy spleen, and parenchymatous nephritis, with very
considerable amyloid degeneration of the glomeruli, as well as
of the vessels and tubuli uriniferi in the papille, together with
simple fatty liver and atrophic induration of the pancreas.
The right femur was the seat of extensive hyperostosis,
combined in the inferior third with a great loss of substance,
whence proceeded fistulous passages; the surrounding parts
had undergone a thickening and condensation, such as is seen
in “ white swelling.”” The lymphatic glands in the thigh and
groin were enlarged, of a clear grey colour, in parts more
transparent. Microscopic examination distinctly showed the
commencement of amyloid degeneration in the follicles,
some of which were wholly reduced to that condition, whilst
others still retained lymph-corpuscles in some of the areole ;
and others, lastly, presented nothing but minute corpora
amylacea amongst normal corpuscles.

Virchow was unable in this case to detect any indication of
amyloid degeneration in the heart or any ‘part of the muscular
system, even in close contiguity with the diseased bone; nor
in the mucous membrane of the respiratory organs and
kidneys. The blood, also, contained no morphological par-
ticles which could be pronounced to be corpora amylacea.

Nevertheless, with respect to the course followed by the
morbid change, it appears indubitable that the incitement to
it proceeds from the diseased bones, whence it extends pro-
gressively to the lymphatic glands, then to the spleen, and
ultimately to several of the secretory organs. Among these
the first to suffer are invariably the kidneys, then the liver,
probably lastly the mucous membrane of the digestive
organs ; and it is a circumstance of the greatest interest, that
both in the kidneys and in the digestive mucous membrane

142 ON THE COURSE OF THE AMYLOID DEGENERATION.

the morbid change always commences in the secretory
vessels, in the same way as in the lymphatic glands, the
spleen, and renal papille, the vessels, and especially the
arterial, are very early affected. In all cases the normal
tissue is removed in proportion to the amount of the new
deposit, and it is not the individual elements which degene-
rate each separately, but the change involves all equally, so
that the ultimate products present a very uniform, homo-
geneous constitution. From al] that appears therefore, it is
highly probable that the affection consists rather in a me-
tastasis of a material formed in the site of the original
diseased action, that is to say, in the bones, and which is
transported to the different parts in a state of solution.

The constitution of the deposit is not everywhere alike, as
has been before remarked by Virchow (‘ Archiv. Bd.’ iii.
p- 144) and Meckel. In particular, it would seem, that the
substance in cases of less complete deposition, though assum-
ing a beautiful red colour even under iodine alone, receives
only an indistinct violet tint on the addition of sulphuric
acid, and is never rendered blue. This was the case very
remarkably in a boy, fourteen years of age, affected with disease
of the lumbar vertebra, whose liver weighed 5 lbs. 13 0z., the
spleen about 73 0z., one kidney nearly 4 and the other 34 oz. ;
in whom the entire parenchyma of the liver, the spleen in its
pulp, the kidneys in the glomeruli, the afferent arteries, and
in the papilla, exhibited the most complete waxy degenera-
tion. With sulphuric acid the iodine-red colour was
deepened, but rapidly became of a dirty violet, or rather of a
dark bluish-red hue, and in parts greenish. In this case,
therefore, the substance existed either in a less perfect form,
or was more mixed with other matters.

( 143 )

ih, FY, L ka WS,

UNTERSUCHUNGEN UBER DEN Bav UND DIE BILDUNG DER P¥FLANZEN-
ZELLE. Von Dr. H. Prinasuem, &c. Grundlinien einen Theorie der
Pflanzenzelle. Mit. 4. Colorirt. Tafeln. Berlin, 1854.

RESEARCHES ON THE STRUCTURE AND ForRMATION OF THE VEGETABLE
Cett. By Dr. H. Prinesnem. (Notice from ‘ Bot. Zeitung,’ May,
1855.)

Tuts memoir, which constitutes the first part of researches

respecting the vegetable-cell, is dedicated to the author’s

friend, Dr. F. Cohn. Its object is to afford a new doctrine
and new views with respect to the primordial utricle, differing
from those at present entertained. The author frst proceeds
to give an account of the primordial utricle, in accordance
with which the principal part in the life of the cell is
ascribed to that element which has been regarded as the
essential, often the only completely closed, nitrogenous mem-
brane of the plant-cell, and upon this subject the statements
of some observers are communicated. <A second section treats
of the disposition of the contents of the vegetable-cell; these
contents consist of the proper cell-fluid, which is always
found in the interior, and of the external, peripheral, sur-
rounding protoplasma (or more shortly, plasma), i in which the
granular portions of the cell-contents are always imbedded.
A distinct lamination is apparent in this plasma, that is to
say, it is constituted of an external, colourless layer applied tu
the cell-wall, and which never presents any granules, and
termed by the author “the cutaneous layer,” and of an in-
ternal, frequently of a dense mucoid consistence and granular
aspect, “‘ the granular layer” of the author. When this granular
layer is of some thickness the chlorophyll granules will be
found lying in its outer portion, whilst the inner part will be
seen to consist merely of a colourless, muco-granular sub-
stance, in which, it is true, many kinds of colourless, coarse,
granular particles occur, but never chlorophyll-granules or
amorphous chlorophy]]. The parietal cytoblast is invariably
lodged in the “ granular layer,’ and when this layer consists
of two portions it is always found in the inner one. In cases
where movement is observed in the cell, it always takes place
at the boundary between the “granular layer” and the cell-
fluid. When the granular layer is thin, the whole of it
moves together with the chlorophyll granules imbedded in it,
but when it is divided into two portions, the movement in-

144 PRINGSHEIM, ON THE STRUCTURE

volves only the inner layers beneath the chlorophyll-granules
(Chara). The author supposes that the formative activity of
the cell-contents is specially seated at the line of junction of
the cell-fluid with the granular layer, and that it is the cause
of the motion. In cases where the plasma does not constitute
a continuous lining to the wall, it cannot, by means of re-
agents, be detached from the wall with a definite outline, but in
the shape of a variously formed net-work of streaks of plasma.
But when it constitutes a complete and uniform covering, it
contracts in a continuous form under the action of the re-
agent, and under certain conditions assumes the false appear-
ance of a membrane. Lastly, in cases where the plasma is
divided, even in the cell, into two distinct layers, not only
does the outer layer appear as a membrane, but the granular
layer also presents a defined boundary. Whenever powerful
re-agents are applied, and a rapid contraction thus induced,
phenomena are always manifested, which necessarily lead to
the assumption of the existence of a primordial utricle,
although many different things haye been included under
that term. But when cells in which the primordial utricle
is displayed in the most distinct form are treated with weak
re-agents, although the same results are ultimately attained,
the process, owing to the more gradual way in which it is
effected, may be accurately observed, and it will thus be
seen that it is not smooth membranes which are separated
from each other, but a glutinous substance which is detached
from a membrane to which it was adherent; the detachment
frequently takes place only partially, and the connexion with
the wall is maintained by isolated threads of plasma, which
become more and more attenuated or are ruptured, until, at
last, the outermost layer of the plasma, contracting, assumes
the appearance of a membrane. This slow separation from
the wall satisfactorily shows, in every case, that the internal
coating of the cell is composed of a muco-glutinous, viscous
substance, and that it is not, properly speaking, a membrane.
The same considerations also confirm the author in his opinion
that, when large cells are treated with slowly acting re-agents,
the contents surrounded by the ‘cutaneous layer” often con-
tract into two, or, more rarely, into several segments, whose
connective portions becoming gradually attenuated are ulti-
mately ruptured, and then isolated, though appearing to be
bounded by an equally even and sharply-defined outline, as
that of the whole contents previous to their division.

In the third section the author speaks of the cell-diyision
in the Conferve, noting, in the first place, its mode of occur-
rence in Cladophora, and afterwards in Conferva, Spirogyra,

OF THE VEGETABLE CELL. 145

and the Zygnemacez in general, in G’dogonium and the Pal-
mellacez. Here also he endeavours to show that Mohl’s view
of the process of division is incorrect, and that it is manifested
in the way he describes only when Mohl’s mode of experi-
menting is closely followed. But when very dilute solutions
are employed it is obvious that a delicate cellulose-septum
exists even in the earliest stage of the division, and which
was overlooked by Mohl. And further, that this delicate
oe is dissolved on the addition of acetic acid when the

“cutaneous layer,” together with the “ granular layer,” are
detached from the proper cell-wall by weak re-agents (syrup);
owing to which circumstance Mohl was unable to perceive
this septum. The author recommends a dilute solution of
chloride of zinc, in order to render the matter clear, from the
circumstance that this agent first detaches the ‘ cutaneous
layer,” the septum still remaining, though it is afterwards
also destroyed. It remained to inquire whether this delicate
septum were a single or a double membrane, and observations
on other alge (Spirogyra), as well as in Cladophora, when the
division was interrupted, show that this wall is double from
the commencement, arising from a portion of the innermost
cellulose-layer thrown out towards the interior. Having dis-
cussed the mode of division of the cell in Spirogyra, and the
Zygnemacee in general, the author proceeds to notice the
process in Gdogonium and the Palmellacew, and finds that
the cells of Gdogonium differ from those above described in
the circumstance that the walls of the secondary cells are not
applied closely to that of the parent-cell, and, consequently,
that a different mode of separation is manifested in this case.
In Gdogonium also a substance is deposited in places between
the parent-cell and the uppermost secondary cell, in the
form of a ring of. cellulose. In the gelatinous Alg@ the wall
of the secondary cell is also not in close opposition with the
parent-cell, a substance being deposited between the two in
all parts.

In the fourth section, the import of the ‘ cutaneous layer,”
as regards the cell, is shown. The subject of the author’s
researches in this respect was afforded by Q¢dogonium, in
which plant the multiplication of the contents does not com-
mence until the elongation of the cell is completed. In this
case the accumulation of the plasma may be observed, and
the “‘cutaneous layer” be seen to constitute an incomplete
streaky lining of the cell-wall. The result of these observa-
tions leads to the conclusion that the cutaneous layer of the
plasma is the same substance as that of which the cell-wall is
directly formed, and that the transformation of the “ cutaneous

VOL. IV. L

146 PRINGSHEIM ON THE STRUCTURE

layer” into the cell-wall takes place when the former has
reached the highest stage of formation—that is to say—when
it constitutes a complete parietal investment. The primordial
utricle might, very readily, be taken for a membrane, but it is
not a membrane distinct from the cell-wall, being merely its
youngest cellulose layer, whose reaction with iodine depends
upon the substances still adhering to it, since it is impossible
that should be pure at this time. Usually it is only the
outermost portien of the ‘cutaneous layer” which is inti--
mately applied to the contiguous cell-wall, whilst the inner
portion is gradually perfected, and eventually comes to be
deposited in the same way. This just formed, youngest cell-
layer also constitutes the folds which advance so as to effect
a complete constriction in the interior of the cell. But it
occasionally also happens that the innermost part of the
“‘ cutaneous layer” becomes a young cell-wall, in which case
the outer portion is left enclosed between layers of cell-wall.
In this way is produced the so-termed “ jelly” in the Palmel-
lace, and the cellulose ring in Gdogonium. All these
formations are merely slight modifications of cellulose, which,
on the addition of acids, is either rendered blue by iodine, or
is converted into a soluble compound belonging to the amyloid
series, and which is not coloured blue by sulphuric acid and
iodine. Consequently, when the latter phenomenon is not
manifested in a membrane, the absence of cellulose cannot
absolutely be assumed.

The mode of division of the parent-cells of the pollen is
discussed in the fifth section. After giving a historical sum-
mary of previous observations on the subject, the author states
the results of his own researches in Allwm Victorialis and
Althea rosea, in which he finds precisely the same conditions
to obtain as exist in the Algz. The formation of the septum
is similar, except that in this case it becomes thickened before
it is completely closed.

The sixth section is entitled “ Nature of the cell-division
in plants.” In this chapter the author shows that the capa-
bility possessed by the cell-wall of forming folds which are
thrown out towards the interior is a general property of that
tissue, and consequently that the act of division consists in
the advancement of this plication till a complete constriction
is effected.

In the seventh section it is shown that the free formation
of cells consists in this: that the contents alone take part in
the formation of the secondary cells, the membrane of the
parent-cell having no share in it. But connected with this,
various cases occur, which are more particularly specified by

OF THE VEGETABLE CELL, 147

the author. He then adverts to the ‘‘swarm-spores,” which
are said to possess only a primordial utricle, and is of opinion
that the earlier limitation of these bodies is simply formed by
the young cell-wall itself, which is unable to resist the pow-
erful influence of re-agents, whilst at a later period, as the
zoospore is more fuliy formed, it presents a stronger and firmer
consistence. Ina note, he remarks that the cilia of the zoo-
spores are not motile organs, but for the purpose of attach-
ment, and that the motion is induced in consequence of
the perforation of the outer membrane, at which points a
more active endosmosis takes place, as may be seen in the
zoospores of Gidogonium, in which, when germinating, the
opening through the outer membrane of the spore is always
visible, from which the first commencement of the root pro-
ceeds.

The eighth section gives a resumé of the foregoing obser-
vations, and in the ninth the author adds a few supplementary
remarks upon the methods to be pursued in researches of
this kind, and particularly upon the application of chemical
re-agents under the microscope, and with respect to the
period at which the division of the cells in the Conferve may
be best observed.

A Manvat or Martve Zoonocy ror THE British Istes. By Puri
Henry Gosse. London: Van Voorst.
A Hanppook To THE Marine Aquarium. By Puimip Henry Gossr.
London: Van Voorst.
AurHouGcH the microscope is more capable of affording
amusement than most philosophical instruments, there are few
who have used it for any length of time but have discovered
that it is an important aid in scientific research, Even those
who have purchased their first instrament to wile away a
leisure hour have gradually got interested in its structure, and
the nature of the objects investigated, so that, although be-
ginning in play, they have ended in work. No one can know
that they have observed, for the first time, a fact new in the
history of science, without the rising of the feeling that con-
stitutes the discoverer in science—the seeker after truth. It
is thus that many great microscopic observers have arisen
among classes who have had no previous scientific edu-
cation that has prepared the world for the result of their
labours. The structure of the instrument, involving as it
does the greatest mechanical accuracy with the most interest-
ing problems of optical science, has excited the attention of
one set of inquirers, whose labours have resulted in the

L2

148 GOSSE ON MARINE ZOOLOGY

present perfection of the instrument. On the other hand, the
habits of minute observation developed by the daily use of
the microscope have produced a number of observers, whose
contributions to science are known wherever its progress
is regarded with interest. To those who are pursuing the
latter path, all works on those departments of science to
which the microscope is applied are of interest.

These two books by Mr. Gosse will be found useful
additions to the microscopist’s library. ‘The Marine Zoology
is the first part of a work devoted to the Zoology of the
sea-side. To those who make a practice of taking their
microscope to the sea-side, this book will be found very
useful, for although it does not give an account of every
species of animal to be met with, it gives descriptions of
families and genera, and contains illustrations of above three
hundred species. It is, however, only right to add that Mr.
Gosse has omitted any description of the Infusoria, the only
really microscopic family of animals. He excuses himself on
the ground of the uncertainty naturalists are in as to the
real nature and position in the animated scale of these minute
beings. We miss also the Rotifera, but surely the same
objections would not apply to giving an account of these
animals,

One of the most useful adjuncts to the microscope is an
Aquavivarium. Even a piece of Vallisneria, Chara or Ana-
charis in a jar will not only afford the materials for interesting
observations in themselves ; but the creatures that nestle in the
leaves of these plants, and which live in the water they cerate,
are almost innumerable. But what is true of these fresh-water
plants and animals is also true of those of the ocean. With
a little care, sea-weeds and marine animals can be kept as
easily for observation as the plants and animals of fresh-
water; but they require care, they demand knowledge; the
domestication of Dulse and Sea Cucumbers is an art, and Mr.
Gosse comes forward with a tiny hand-book of instructions for
those who are ignorant and need a guide. From this book
we give a short extract, by way of recommendation :—

In deep pools, and narrow clefts near the verge of lowest water, where
the overshadowing rock excludes the sun’s rays and imparts a genial
obscurity, grow several of our most delicate and beautiful Algae. Fore-
most among them is the Oak-leaved Delesseria (D. sanguinea), with tufts
of crimson leaves, exquisitely thin, much puckered at the edge, and
strongly nerved. ‘The Jrida, whose leaves are smooth and leathery, and
of a dark-brownish scarlet, is often the companion of the former. Here,
too, we find the Phyllophora, another weed of brilliant red hue, with
unnerved leaves much divided, giving origin to other leaves, and these
again to others. It is usually much covered with the cells and shrubs

AND THE AQUAVIVARIUM. 149

of various species of Polyzoa, exquisitely beautiful objects for the micro-
scope. The Gelidiwm corneum is another fine red weed, commonly of
small size and slender, but prettily fringed with processes all round the
edges of the leaves. This and the preceding are very hardy in confine-
ment, and form very suitable plants for an Aquarium.

When we can no longer work at so low a level, we recede to the slopes
of the ledges yet uncovered, and find other species in the quiet sheltered
pools. A weed is found here, growing in dense mossy patches on the
perpendicular and overshadowed edges of the rock, which, when examined,
looks like a multitude of tiny oval bladders of red-wine, set end to end in
chains. This pretty sea-weed is called Chylocladia articulata.

Here also grows the stony Coralline, a plant bearing some resemblance
to that just named, in the peculiar jointed form of its growth. Low-lying
pools are often incrusted with a coat of stony or shelly substance of a dull
purple hue, having an appearance closely like that of some lichens; the
crust investing the surface of the rock, and adhering firmly to it, in irre-
gular patches, which continually increase from the circumference, in con-
centric zones. This is the young state of the Corallina officinalis, which
by and by shoots up into little bushes of many jointed twigs, diverging on
every hand, or hanging in tufts over the edges of the rock-pools. Young
collectors are eager, I perceive, to seize such specimens as are purely white ;
but this condition is that of death; in life and health, the shoots are of
the same pale purple hue as the lichenous crust. This plant in both states
(for plant it undoubtedly is, though principally composed of lime, and of
stone-like hardness) is suitable for a tank, as it survives and flourishes
long; and your pieces of rock-work you may select from such places as
are covered with the purple crust.

The most valuable plant of all for our purpose is the Sea Lettuce (Ulva
latissima). Every one is familiar with its broad leaves of the most bril-
liant green, as thin as silver-paper, all puckered and folded at the edge,
and generally torn and fretted into holes. It is abundant in the hollows
of the rocks between tide-marks, extending and thriving even almost to
the level of high water, and bearing with impunity the burning rays of
the summer’s sun, provided it be actually covered with a stratum of water,
even though this be quite tepid. It therefore is more tolerant than usual
of the limited space and profuse light of an Aquarium, where it will grow
prosperously for years, giving out abundantly its bubbles of oxygen gas
all day long. It is readily found; but owing to the excessive slenderness
of its attachment to the rock, and its great fragility, it is not one of the
easiest to be obtained in an available state. The grass-like Enteromorphe
have the same qualities and habits, but their length and narrowness make
them less elegant. The Cladophore, however, are desirable; they are
plants of very simple structure, consisting of jointed threads, which grow
in dense brushes or tufts of various tints of green. Some of them are
very brilliant; the commonest kind is C. rupestris, which is of a dark
bluish-green ; it is abundant in most localities.

GENERAL OUTLINE OF THE ORGANISATION OF THE ANIMAL KINGDOM, AND
MAaNnuAL or Comparative AnatoMy. By Tuomas Rymer JONES.
London: Van Voorst.

Turis work has long been one of the most complete in our
language devoted to the subject of Comparative Anatomy.
At the same time such has been the great advance of anato-

150 JONES’S COMPARATIVE ANATOMY.

mical and physiological science, especially under the influ-
ence of microscopical observations, that a book never so com-
plete in 1841 could hardly be regarded as a guide in 1858.
It was, therefore, with pleasure that we saw announced a
second edition, as in its plan and general arrangement we
know of no other book so well adapted for the purposes of
the general student. A glance at the present edition indi-
cates that the author has added a considerable quantity of
new matter. The plates, which were excellent in the first
edition, have been increased from 330 to 398, and this even
does not indicate the number of new plates, as many of the
old ones have been withdrawn, The new matter, we find,
consists principally of additions amongst the descriptions of
the invertebrate animals, and of the history of their develop-
ment. ‘The student will also find in the account of the higher
animals a very acceptable description of the homologues of
the vertebrate skeleton. Professor Jones excels in the art of
writing plainly and gracefully; and his additional matter, in
point of style, is equal to anything in the original work.
Had it been consistent with the intention of the volume, we
should have been glad to have seen more of it re-written.
Some of the old matter is getting quite old, and references to
*‘ recent” researches in 1841 should not have been left in an
edition of 1855. We also find some indications of haste in
the incorrect spelling and use of names. In spite of many
serious deficiencies, and the absence of much information,
especially with respect to the Protozoa and lower classes of
animals afforded by numerous recent researches, defects in
which Professor Jones’s work is not singular, we can still
recommend his Outline as one of the best introductions to the
study of the animal kingdom that we at present possess.

( 151 )

NOTES AND CORRESPONDENCE.

Finders and Indicators.—Since Mr. Tyrrell first broached the
idea of a finder, the subject has frequently engaged my atten-
tion, and although my own modification of his instrument
enabled me with great ease to hit upon any object, however
minute, even when using a plain stage to which the original
was not adapted, I yet became early aware that a great
improvement would be effected if the ivory slip could be
altogether dispensed with; as it required, when using high
powers, more steadiness of hand for its accurate use than
many people are fortunate enough to possess, and as the read-
ing the figures through the microscope was not always easy.

Dr. Wright’s contrivance, which appeared in the same
number of the journal as my own, was very satisfactory as far
as the individual microscope for which it was used was con-
cerned ; but as no two makers form their instruments exactly
on the same principle, it was inapplicable to a great number
of moveable stages, although in the modified form suggested
by Dr. Wright at the end of his paper, available for plain
ones. It had, too, the disadvantage of being non-transferable
(or “selfish,” as Mr, Bailey calls it), from which charge, by
the way, I must defend Mr. Tyrrell’s and my own instru-
ments, inasmuch as they formed very convenient packing
cases for slides, and it was only necessary to wrap them in
paper, and enclose them in a twopenny stamped envelope to
insure their safe carriage to your correspondent. My own
was suited for the use of any microscope, and was in this
sense an “ Universal Indicator ;” its great drawback was, as
I have stated, the ivory slip. I next tried the vertical and
horizontal scales ruled on card, but failed from my inability
to insure satisfactorily an uniform position for it on any and
every moveable stage; in fact, the idea wanting was the
ingenious one of Mr. Bailey—the separate central piece for
continuing the vertical and horizontal lines to their intersec-
tion. The instrument which [ now forward you (a rough and
home-made specimen), and of which I also enclose an out-
line, is used with the greatest possible ease, and appears to
me to possess the following advantages. Its steadiness is sufli-
ciently insured by a side check to the left hand, which rests
against the stage. ‘The hole in the middle of the boxwood is
furnished with a rabbet or ledge for the reception of a disk of
bone, perforated accurately in the centre with a very small
needle, and which can be entirely and steadily removed by
seizing a little brass peg attached to it with the forceps.

152 MEMORANDA.

There is no necessity for ruling the slides. The scaling is
simple, and the cost of the instrument is very trifling.

0 5 10 15 20 25 30 35 40 45 50 55 6065 70 75 80 85 90 35 100 105

Box-wood Finder, with bone centrepiece, i situ.
‘Lhe dotted ring shows the rabbet on which the centrepiece rests.
a, brass pin attached to centrepiece.
b, two brass pins for steadying the instrument against the left side
of the microscope stage.

N.B.—The scales may be ruled on brass or bronze and inlaid, and
horizontal lines might be ruled on the surface of the instru-
ment as a guide for ‘placing x the slide.

The following directions for its employment will be sufficient.
Ist. Place the instrument on the stage, and find the central
needlehole through the mic roscope. 2ndly. Remove the bone
disk with the forceps held in the right hand. 3rdly. Place
the slide on the wood (the named side always to the right),
and make the requisite movements with the left finger and
thumb, vot with the stage screws.

The position of any object occupying the centre of the
field will now be accurately marked by the sides and ends of
the slide on two, at least, out of the four scales, and ean be
registered with a diamond point on the glass.

To find the object again is of course extremely simple
find your centre before removing the disk, and then place
your slide according to the letter and number marked on it,

As the boxwood should be at least an eighth of an inch in
thickness, it would be an easy matter to excavate a space
3 inches by | inch on its under side for safely stowing awaya
slide in case of transmission by post or parcel.

MEMORANDA. 153

Mr. Bailey alludes to the possibility of making the move-
able stage its own indicator, but the old and ever obstinate
vice of “selfishness” comes in his way, and he discards the
idea in favour of his paper instrument, forgetting, as it seems
to me, that his own very ingenious contrivance, the moyeable
centrepiece, is easily applicable to the stage. I would sug-
gest, then, that if makers would rule their stages with the
required vertical and horizontal scales of 50ths or 100ths of
an inch, agreeing to adopt an uniform given distance from the
middle for the commencement of each scale, and would
supply an ivory disk, perforated in the centre for adjusting
purposes, much would be done towards the attainment of a
good “ Universal Indicator.” One trifling difficulty remains,
it is this: the disk (as will be found on experiment) should
not exceed 8-10ths of an inch in diameter, and the central
apertures of microscopes are usually much larger than this.
The simple remedy would be to furnish a metal or bone
collar, which would fit the aperture, and remain in it while
employing the finder. It strikes me, too, that as the scale
divisions of less than 50ths of an inch may be puzzling to any
but sharp eyes, and as finer divisions would certainly be
advantageous, larger ruling might be adopted, and a small
vernier made to slide in a groove by the side of each scale.—
Tuomas Epwarp Amyort, Diss, Norfolk.

On Micrometers applied to Microscopes.—T|he ordinary
stage-micrometer, as constructed by the best English and
foreign opticians, cannot be directly applied to the measure-
ment of very minute objects. Although it can be procured at
a moderate price, and with divisions beautifully ruled on
glass at intervals of 1-100th of a millimetre apart, the scale
is far too coarse for the use of the histologist ; and it is usually
quite impossible, in examining certain objects under high
magnifying powers, to bring their edges into proper focus
while the ruled lines of the scale continue tolerably defined.

The eyepiece-micrometer, consisting of a scale ruled on
glass, and inserted in the stop or diaphragm of the ordinary
negative eyepiece, is a very convenient instrument, enabling
the observer, when using a magnifying power of 500 or 600
diameters, to estimate spaces of about 1-200th or 1-300th of
a millimetre with tolerable precision, in favourable circum-
stances. But the breadth of the lines on the best ruled eye-
piece-scale is so considerable, and the shadows caused by
their channels so perplexing, even when the illumination is
carefully managed, that, where extreme accuracy is required,
other apparatus must be employed.

The cobweb screw-micrometer, when well constructed, is a
far more perfect instrument; but, as Mr. Quekett remarks,

154 MEMORANDA.

“the measurements made by it are by no means so delicate
as they appear to be.” In taking a unit, from which to con-
struct the scale, a stage micrometer must be employed, and on
the accuracy with which this is graduated depends, of course,
the exactness of the subdivisions effected by means of the
screw. This objection applies equally to all eyepiece-micro-
meters; but the screw-instrument has the positive disad-
vantages of being constructed of parts very apt to become
deranged, and capable of being replaced by none but a first-
rate workman. The effects of friction cannot be wholly
obviated; the screw is apt to wear, and to wear unequally ;
and the uniformity of all its parts,—even when it leaves the
workman’s hands,—may be reasonably suspected. The price
is necessarily so high as to preclude its general employment
by those engaged in microscopic observations.

In Henle and Pfeifer’s ‘ Zeitschrift fiir Rationelle Medicin’
(band X. heft 1), Hermann Welcker, a medical student at
Giessen, proposes a new kind of micrometer, capable of
furnishing indications of extreme delicacy, and in elegance
of principle and cheapness far surpassing the cobweb screw-
micrometer.

The following description will enable any one familiar with
the elementary principles of trigonometry to comprehend
the mode of constructing and using such an instrument :—

Construction.—Across the stop of an ordinary negative eye-
piece, two very fine threads, from a small spider cocoon, are
stretched at right angles to each other, and, by means of a
little copal varnish, are fixed in such a position that the
shorter intersects the longer thread, cutting off about one
quarter of its length. T He relative position of the threads is
shown in Figs. Il. and IIL, where they are indicated by the
letters A Band CD. To ae upper part of the tube of the
microscope is fixed transversely a brass plate, along which
plays a pointer, firmly attached to the eyepiece immediately
beneath its milled rim, The appearance of this apparatus is
shown on a reduced scale in Fig. I. Upon the edge of the
brass plate is drawn an arc of a circle concentric with the

Fig. I.

eyepiece, and this arc is then subdivided into degrees, and
any fractional parts which may be required.

MEMORANDA, 155

By experimenting with a stage micrometer, we next endea-
vour to ascertain how far the pointer must be moved, in order
that the crossed thread shall traverse a space in the field
corresponding to 1-100th of a millimetre. By simply mani-
pulating on the stage of the instrument, the stage micrometer
can easily be put into the position shown in Fig. II., the long
line A B accurately coinciding with a line of the micrometric
scale. ‘The eyepiece is then cautiously rotated, till the cross
in the field, passing along the imaginary dotted circle in
Fig. II., seems to touch the next line of the stage-scale, the
long line now assuming the position a 6. The arc traversed
by the pointer during this rotation is then read off,—we shall
suppose it an are of 8°. The sine of the corresponding arc
of the dotted circle will, of course, indicate exactly 1-100th
of a millimetre ; and from this simple foundation any measure-
ment—. e., the length of the chord of any given arc in that
circle—may be calculated ; for the chord of any are being
equal to twice the sine of half that arc, the value of the chord
of 8° is found as follows :—

Proportion.
As sin. 8° :; *01 Millimetre : : 2 sin. 4° : chord 8°
Calculation.
Log. 2 sine 4° = 9°1446145

Log. ‘01 Millim. 2-0000000

7°1446145

Subtract Log. sine 8° = 9°1435553

Chord 8° = Num. *0100244 Millim. = 2°0010592

Fig. II,

156 MEMORANDA.

The same result may be obtained from the following pro-
portion, both sine and chord being supposed drawn :-—

Proportion.
Rad. : ‘Ol Millim. : : secant 4° : chord required.

Calculation.

Log. secant 4° = 10°0010592

Log. -01 Millim. = 2*0000000

Subtract Log. Radius = 10°0000000

Chord 8° = Num. *0100244 Millim. = 20010592

The equivalent number -0100244 is the required value of
the chord of 8° in fractional parts of a millimetre. This or
some other chord having been carefully determined by the
instrument-maker, or observer, it should be noted down, as
essential for the exactitude of all measurements to be after-

wards made. It will save trouble if its logarithm be also
recorded,

Mode of using the Instrument.—Suppose we wish to measure
the long axis of an object, such as M N in Fig. III., we so
arrange it on the stage that the cross in the field will, when
the eyepiece is rotated, touch first the extremity M, and then
the other extremity N. The arc Aa, traversed by the

Fig. III.

a B

pointer, is read off from the brass scale. The chord of the
corresponding are of the imaginary dotted circle is the measure

MEMORANDA, 157

of MN. Its length may be calculated with the greatest ease
by the help of the ordinary logarithmic tables of sines. In
comparing chords, we use the sines of half their including
arcs, as in the example which is appended :—

ExampLe.—See Fig. III.

The arc Aaisfound = 38°
Required the length of M N.
Proportion.
Sine 4° : 0100244 Millim. : : Sine 199: M N.
Calculation.
Log. 0100244 Millim. 2°0010592

Log. sine 19° 9°5126419
75137011

Subtract Log. sine 4° 8°8435845

M N. = Num. ‘0467861 Millm. = 2-6701166

In like manner the length of any other chords of the dotted
circle may be easily determined ; and a table—if required—
drawn up, from which the measure corresponding to each
degree of the scale can, by mere inspection, be at once ascer-
tained.

When the eyepiece rotates smoothly in the tube of the
microscope, and a magnifying power of 500 or 600 diameters
is used, measurements may be made with such an instrument
with the utmost nicety. Welcker recommends that the top
of the tube of the microscope should terminate in a hollow
cone, into which is received a conical collar, supporting the
pointer, and slipt on immediately beneath the milled rim of
the eyepiece. The errors of manipulation should hardly
exceed 1-40,000th of an inch,—a degree of exactitude scarcely
attainable by the cobweb screw-micrometer. An instrument
constructed for me, by Mr. James Bryson, of Edinburgh, on
the plan above described, has been tried against a finely-
finished screw-micrometer, and found to perform with very
great accuracy.—W. Rosertson, M.D., Monthly Journal of
Medical Science.

Cilia in Unicellalar Plants.—In consequence of several com-
munications appearing in the ‘ Microscopic Journal,’ announc-
ing the discovery of the existence of cilia both externally and
internally, in the Desmidiee and Diatomacee, I have been
induced to make a careful series of examinations of some
of these objects, under all varieties of illumination, dif-
ferences of aperture, and magnifying power.

158 MEMORANDA.

From being somewhat limited in a supply of the Closterium
lunula, I have used the C. acerosum as the chief subject of the
investigation, from the fact that all the motile phenomena are
precisely analogous, and quite as easily marked as in the
other. I possess a white flint glass bottle (closed with a cork),
containing an aquatic plant. The earth at the bottom is
covered with a stratum of the C. acerosum, and each decaying
stem of the plant, is also sheathed with a bright-green coating
of the same, in a vigorous state of growth. Specimens in
various stages taken direct from this source, were the objects
observed.

In the C. acerosum, the endochrome and primordial utricle
will sometimes be found partly contracted in a longitudinal
direction, at the same time drawing the swarm-spores and va-
cuole with it ; a considerable clear space is thus left at the end
of the frond, wherein the motion of the protoplasm can be very
distinctly seen in the act of flowing and returning in thread-
like currents, which shift their position, and frequently take
a spiral direction, in a manner exactly resembling the circula-
tion in the hairs of some plants.

The vital protoplasm contained within the Desmidiee, has a
similar granulated appearance, and is endowed with the same
active powers of locomotion as in other plants. Having
then a tendency per se to run in rapid currents, why should
the presence of cilia be requisite for assisting a motive
force already sufficiently energetic? Without being pre-
judiced by any obvious reply to this question, I have tried to
discover the presence of cilia, with the aid of the most perfect
appliances that the optician’s art can furnish, but without
success. So far as eyesight will inform me, there are no
indications of these organs either externally or internally—
neither on the membrane of the primordial utricle, or as an
investment, lining the inner wall of the frond—all the undu-
lating motions and currents appear to be caused entirely by
the movements of the protoplasm.

As I can, at will, adjust the illumination, conjointly with
other circumstances, so as to produce the most positive ap-
pearance of moving cilia, not only internally, but also on the
exterior of the frond, I will briefly mention the causes of this
fallacy. The effect of oblique sunlight, or any other powerful
source of illumination, in causing a refractive atom to appear
elongated, as a ray or line, is too well known to need comment,
as is the fact that this ray will appear to extend over the boun-
dary of a cell-wall, or other adjoining body. Another cause
of deception arises from a large angle of aperture ; when a thin
plane or membrane is viewed, in such a position as to be

MEMORANDA. 159

parallel to, and coincident with the axis of the object-glass, the
cone of rays will be bisected, and the opposite sides of the
surface brought into the eye simultaneously: consequently, a
somewhat confused definition is the result. A protuberance
on one side will seem to penetrate and project through on the
other side. With the aid of a diagram it would be easy to
demonstrate mathematically the optical principle to which this
appearance is due, but in the present case, a familiar ex-
ample will, perhaps, suffice to prove the fact.

In viewing the circulation of the Anacharis with a large
aperture, the chlorophyll granules traversing along a straight
and thin septum, (if the position is favourable) appear to
project into the neighbouring cell, seeming to pass directly
under the line of the pelewalll Smaller particles will
apparently travel within the substance of the wall, and in case
of a boundary or single cell, or in unicellular plants if the
surrounding water has nearly dried up, the rim or prism
remaining round the exterior, causes irregular refracted
images of the particles of protoplasm to appear outside the
cell, bearing such a remarkable similarity to external cilia,
that the passing shadows may even be mistaken for currents
in the water; I do not say positively that these are the causes,
giving rise to the appearance of cilia observed by others, I
merely mention them as facts to be borne in mind.

I may also state that | have never been able to discover the
orifice, said to have been seen at the extreme ends of the
Closteria. It may be assumed that if such an opening existed
it would have something like a structural margin, of sucha
size as to allow its position at least to be visible under the
microscope, but not the slightest break can be observed in
the laminated structure that the thickened ends display.

All attempts that I have made to ascertain the existence of
cilia in the Diatomacee have been equally unsuccessful. How
then are the active traversing motions of these organisms to
be accounted for? If caused by the action of cilia, such
extremely rapid impulses would be required, to propel the
comparatively large body through the water, that surrounding
particles would be jerked away far and wide; a similar effect
would be observed if the propulsion was caused by the reaction
of a jet of water; which, according to known laws of hydro-
dynamics, must necessarily be ejected with a rapidity sufficient
to indicate the existence of the current, a long distance astern.
I consider that there is no ground for assuming the motions
of the Diatomacee to be due to either of these causes. They
are urged forward through a mass of sediment, without dis-
placing any other particles than those they immediately come

160 MEMORANDA.

in contact with, and quietly thrust aside heavy obstacles,
directly in their way, with a slow but decided mechanical
power, apparently only to be obtained from an abutment
against a solid body. In studying the motions of the Dia-
tomacee, I have frequently seen one get into a position such
as to become either supported or jammed endways between
two obstacles. In this case particles in contact with the sides
are carried up and down from the extreime ends, with a
jerking movement, and a strange tendency to adherence; the
Diatom seeming unwilling to part with the captured particle.
Under these circumstances I have distinctly perceived the
undulating movement of an exterior membrane; whether this
envelopes the whole surface of the silicious valves | am not
able to determine, nor do I know if the existence of such a
membrane has yet been recognized. The movement that I
refer to occupied the place at the junction of the two valves,
and is caused by the undulation of what is known as the
‘‘ connecting membrane.” ‘This will account for the pro-
gressive motion of the Diatomacee, whick is performed in a
manner analogous to that of the Gasteropoda. The primary
cause, however, is different, and not due to any property of
animal vitality, but arises, in my opinion, merely from the
effects of vegetable circulation. I have observed several cor-
puscles of uniform size, travel to and fro apparently within the
membrane, which is thus raised in waves by their passage.
From this I, therefore, hazard a conjecture, with respect to
the movements of the Desmidiee. (Their progression is but
seldom seen, and then extremely slow, and chiefly confined to
elongated specimens, as the Closteria.) As there are no indi-
cations of either external orifices or cilia, may not their loco-
motion be effected by the currents of protoplasm forcing their
way between the primordial utricle and outer tunic, which
will thus be raised in progressive waves, if the investment
happens to be ina suitably elastic condition ?—F. H. Wennam.

Remarks on Wir. Wenham’s paper, on “ Aperture of Object-glasses.”"
—As Mr. Wenham now frankly admits the correctness of my
statements with regard to the possibility of resolving difficult
test objects, even when balsam-mounted, no further remarks
are necessary upon that point, but a few words of comment
are required by other portions of Mr. Wenham’s paper.

That my reply was written before I could have had any
knowledge that Mr. Wenham had recalled his remarks, in
which doubt appeared to be thrown on my positive statement
of facts, will sufficiently appear by the date of my reply, which
was published in the ‘American Journal of Science’ for

MEMORANDA. 161

January, 1855, the very time in which Mr. Wenham’s retrac-
tion of his remarks appeared in the ‘ Quarterly Journal
of Microscopical Science.’

If Mr. Wenham finds anything objectionable in the form of
my reply, he should bear in mind that the discussion is not
one of my seeking, and that I put the best possible construc-
tion upon his remarks which called in question the correctness
of my assertions. I am utterly averseto anything like scien-
tific controversy, and would make no further remarks in this
connection, if Mr. Wenham had not so entirely mistaken my
statement, as to represent me as having published sheer
nonsense.

The statement on which Mr. Wenham animadverts is as
follows: ‘*'The error in Mr. Wenham’s arguments will be suffi-
ciently obvious to any one who will trace the course of a
divergent beam out of the balsam, instead of into it; and it
will then be seen that large angles of aperture are as useful
for balsam-mounted specimens as for others.” This state-
ment, as zt stands, I still hold to; but I must protest against
its being considered as “tantamount” to any such absurdity
as that into which Mr. Wenham has translated it, which
is indeed “contrary to reason.” I mean, however, to assert
what Mr. Wenham so emphatically denies, viz.: that it does
make a difference, whether rays are traced into a refractive
medium or owt of it. I cannot admit that these two cases
“come to precisely the same thing.”

Mr. Wenham surely does not need to be told, that if “the
trigonometry of optics establishes anything, it proves that the
same medium which bends an incident ray towards the per-
pendicular when it enters, will bend it from the perpendicular
when it emerges. Hence a beam of divergent rays, from a
point within a medium, is rendered still more divergent when
it emerges, and in fact is spread out, so that the extreme rays
which emerge are in the plane of emergence, or make an
angle of 180° with each other.

Mr. Wenham seems to confine his attention to the fact,
that a large portion of the rays from a balsam-mounted object
are lost by internal reflection. This, of course, I never meant
to deny; and, in fact, it is one obvious reason why balsam-
mounted test objects are, as I long ago stated, far more difficult
to resolve than when mounted dry. The loss of a portion of
rays in this manner, however, has nothing whatever to do with
the present question, which is simply whether, of the rays that
do emerge (and which make every angle with each other, from
0° to 180°) more will be collected by a lens of large or small
aperture. Certainly Mr. Wenham cannot deny that the larger

VOL. IV. M

162 MEMORANDA.

aperture will receive the larger number of rays; and if so,
then my statement is fully confirmed, that “large angles of
aperture are as useful for balsam-mounted objects as for
others.”

The distinction | have alluded to above, between the inten-
sity of illumination of the balsam-mounted object, and the
effect of large angles of aperture is alluded to by Dr. Robinson,
of Armagh, in his paper ‘‘ On measuring the angular aperture
of object-glasses,” published in the Proceedings of the Royal
Irish Academy, January 23, 1854, where he states in a note,
that the effect of mounting in balsam is, in fact, equivalent to
reducing the aperture of the objective below 100°, as far as
allumination is concerned, though a much larger one may be
required to take in the pencil—J. W. Batrey, West Point,
New York.

Mohl on Chlorophyll.—In a recent number of the ‘ Annals and
Magazine of Natural History,’ Mr. Henfrey has translated an
interesting paper by Mohl on Chlorophyll. This paper thus

concludes :—

“Gathering all these points together,—the occurrence of Chlorophyll
in cells which contained no starch; the occurrence of membrane-like
Chlorophyll-structures, not preceded by any corresponding starch-strue-
ture, or accumulations of starch-grains ; the growth of Chlorophyll-globules
after the starch-grains have vanished from them ; the simultaneous increase
in size of starch and Chlorophyll-globules in other plants ;—-we are neces-
sarily led to the conclusion, that Chlorophyll is not produced by the
transformation of starch-grains, but that the two structures, though fre-
quently connected together, originate independently of each other. The
starch may exist earlier, and the Chlorophyll accumulate around the
starch-grains as around a nucleus—as may be seen so clearly in the
internal starch-bearing cells of a potato when exposed to the light, and,
in extremely numerous cases, in the leaves of buds; and, on the contrary,
the starch-grains lying in Chlorophyll-globules may increase in size inde-
pendently, and even be formed in Chlorophyll which originally contained
no starch.”

Mr. Henfrey has added the following notes :—

‘¢My own observations fully confirm the statement that starch-grains
may originate in Chlorophyll-globules at first totally devoid of starch; 1
have traced the formation of groups of starch-grains in this way in the
interior of Chlorophyll in the Hepaticee and other Cryptogamous plants.
There can be little doubt that the Chlorophyll belongs to the protoplasmic
substances of the cell-contents, and is capable of producing stareh equally
with the colourless protoplasm. From the mode in which starch-grains
are formed, both in Chlorophyll and in colourless protoplasmic masses, I
am inclined to regard it as a product formed by deposit or secretion on the
inside of cavities or vacuoles of the latter, by a process analogous to the
formation of the cellulose layers on the outside of the primordial utricle.
I do not find the protoplasmic nucleus described by Criiger in all starch-
grains. This would account for most of the phenomena observed. At

MEMORANDA. 163

the same time it would afford an argument for those who doubt the dis-
tinct existence of a determinate layer or primordial utricle on the outside
of the protoplasm. Our author’s statements as to the pellicular character
of the apparent membrane described by Nageli on starch and Chlorophyll-
corpuscles, would seem to apply to some extent to the so-called pri-
mordial utricle. Pringsheim has recently published some important ob-
servations on this head, which I trust to be able shortly to test and
report on.

“The observations of Mr. Grundy agree, in some respects, with those I
have made in a great variety of cases, but the striew are certainly not
superficial, and I doubt the existence of the outer membrane. I[ think
there is merely a pellicle of protoplasm, coagulated on the starch-grain
when re-agents are added. This would appear to dip between the con-
stituent grains of groups ; in some cases, however, the interposed pellicle
becomes obliterated, and the groups, mostly pairs in such cases, have the
outer layers common over the whole. It seems to me that there is a
fallacy in the various accounts of the membrane of the starch-granule,
founded on the experiment of boiling starch, assuming, as I do after
repeated experiments, that the main body of the structure is that of con-
centric lamin of a tough material. If there were an enclosing membrane
distinct from the starch-layers, thick enough to bear expanding to many
hundred times its original superficial dimensions, this must be thick enough
when unexpanded to be clearly visible as a well-defined coat. ‘lhe saccate
bodies obtained by boiling really result from the whole softened substance
of the granules becoming blown out (like india-rubber bottles) by a pro-
cess of endosmosis. ‘The internal substance softens and absorbs water
more readily than the other—a sufficient cause for the endosmosis. This
difference of condition of the layers is proved by an experiment I have
repeatedly made with fresh potato-starch. If we attempt to cut it with
a knife, it breaks with a roughish fracture, like a lump of partially-hardened
clay ; if the fragments are placed in cold water, the internal part of the
starch will often swell and protrude irregularly, while the outer layers
retain their shape. I cannot confirm Mr. Grundy’s statement, that the
“skins” can be boiled until they no longer take the blue (or bluish)
colour with starch. Still, since after boiling, as in treatment with sul-
phurie acid, the colour of the substance with iodine tends more and more
to pinkish purple, it is possible that long boiling may change this condi-
tion, just as roasting does.”

@n the Microscopical Structure of the Victoria Regia (Lindl) _
The stomata are nearly circular, formed of two crescentic
cells. They are minute, measuring only the 1-960th of an
inch in diameter, and so closely placed that one square inch
of epidermis will contain 139,845. An ordinary-sized leaf,
4 feet in diameter, with a surface of 1850-08 square inches,
will thus contain upwards of twenty-five millions of stomata
(25,720,937).

The lower surface of the Victoria leaf is somewhat peculiar.
It exhibits no stomata, but is thickly clothed with flexuous
hairs, consisting of cylindrical cells, and arising each from a
small round basal cell very distinct both from the other cells
of the hair and those of the epidermis, which latter are filled
with diffused colouring matter, mostly red, but in some blue,

M 2

164 MEMORANDA.

and a few are without colour. These hairs average about the
1-55th part of an inch in length, by the 1-490th of an inch
in breadth. There are seen scattered over the surface, in
addition to the hairs, numerous round cells, precisely similar
to those which form the bases of the hairs; these apparently
indicate non-developed hairs. The arrangement of these cells
(taking together those which form the basis of hairs and those
whose hairs are abortive) is so strikingly similar to the
arrangement of the stomata on the opposite surface of the leaf,
as to suggest the question whether these cells are not homo-
logous with the stomata; are in fact the cells from which
stomata would be evolved if they were produced. This idea
is strengthened by the fact that a trace of chlorophyll is seen
in these cells, while it is entirely absent in the ordinary
epidermal cells, but present in well-defined globules in the
cells of the true stomata. Whatever be the homological
relationship between the hairs and the stomata, there can be
no doubt that the cells to which I have alluded represent un-
developed hairs; and, indeed, Dr. Lankester has long ago
shown the tendency to non-development of hairs on aquatic
plants, such, for example, as in the case of Callitriche, where
peculiar rosette-shaped cells in the epidermis represent non-
developed hairs.

If a portion of the leaf of the plant be held between the eye
and the light, it will be seen that the thinner parts are per-
forated with numerous minute holes; indeed these are dis-
tributed more or less over the whole leaf, excepting those
parts occupied by the ribs. The nature of these openings,
and their purpose in the economy of the plant, have given
rise to some speculation. Hooker describes them thus :—
‘“* Conspicuously may be seen the numerous pores or stomata ;
these are circular, generally margined with red, and apparently
formed of a thin membrane, surrounded by a circle of red
cells,” and Fitch’s drawing shows a membrane stretched across
the pore. This is only the case, however, in the early con-
dition of the leaf; at maturity, the thin pellicle disappears,
leaving an actual perforation, measuring in the specimens I
examined the 1-84th part of an inch across. The develop-
ment of these pores has been carefully described by Planchon,
who has given them the name of Stomatodes, and subse-
quently by Trecul. Planchon believes that they are designed
to permit the escape of gases which are disengaged from the
water, and would otherwise collect in the spaces formed
between the ribs and the under-surface of the leaf. It appears
to me, however, that they might with equal propriety be
regarded as intended to drain off the superfluous water which,

MEMORANDA, 165

from rain or other sources, might collect upon the surface of
the leaf, whose edges, being turned up as a bulwark against
the surface ripple of the water, would prevent its speedy
escape otherwise ; and we well know that such a huge mass of
cellular tissue shut out from the air by a covering of water
soon dies. But, I believe, neither hypothesis explains the
real nature of the so-called stomatodes. It is desirable to
understand their homology before we speeulate on their func-
tions. They have none other than a fanciful relationship
with stomata. In their own structure they present no cha-
racters in common with stomata, nor are they even connected
with true stomata; on the contrary, there is an absence of
stomata around their margin on the upper surface, the thin-
ning of the tissue at that part rendering such organs un-
necessary.

While the perforations may serve both the purposes indi-
cated above, and thus afford an example of the modification of
a structure to suit the requirements of a plant, such as we see
every day in the organs of animals and plants, I believe that
they are merely the simplest form of a reduction of tisstes
more fully brought out in other plants. We well know the
tendency of phanerogamous plants growing in water to lose
the soft tissues of their leaves; Ranunculus aquatilis is a
familiar example wherein the submersed, as well as some of
the floating leaves, exhibit only a very partial development of
parenchyma; we also know that this reduction of parenchyma
is not confined to leaves actually submersed, but is parti-
cipated in by those which float upon the surface. Ouvirandra
fenestralis is a striking example, the parenchyma being so
much reduced as to give the leaf the appearance of a skeleton
leaf. In the Victoria it appears to me that the perforations
indicate the beginning, as it were, of a reduction of this
kind, which if it proceeded far enough would result in a
lattice-work leaf like the Ouvirandra, represented only by the
strong-ribbed venation with which the Victoria is furnished.
In fact, the thinness of the intercostal parts of the leaf, as com-
pared with the ribs, is an equally striking indication of such
a reduction. Viewed from this point of view, these pores
resolve themselves into a form of development with which we
are familiar in other plants, and lose their supposed singu-
larity as a feature of structure peculiar to the Victorza.—
G. Lawson. Proceedings of Botanical Society.

The Stomachs of the Polygastrica.—A spirited controversy
exists concerning the internal structure of the so-called Poly-
gastric Infusoria. In England the subject has not met with

166 MEMORANDA.

so much attention as abroad, where Professor Ehrenberg, of
Berlin, and Dr, Pouchet, of Ronen; stand at the head of one
party of naturalists ; whilst opposed to them is a large num-
ber, supporting the views of Dujardin in France, and of
Siebold in Germany.

Having had my attention attracted to this dispute, and
conversed with many of those naturalists who take an active
interest in the controversy (especially with Dr. Pouchet,
whose judgment I find in all cases to be the least prejudiced),
curiosity has tempted me to scrutinise their theories with
care, and practically to test their merits.

Briefly stated, the following are the views espoused by the
respective parties of naturalists :—

Ehrenberg states, the digestive apparatus of the Polygas-
trica (now known as Tnfusoria) to consist of many globular
stomachs. In the higher forms, these stomachs are connected
by a bowel, which has a receiving and a discharging orifice,
situated on the external integument of the Animalcule; in
the lowest types the bowel is dispensed with; a number of
stomachs, along with a single orifice, being all that Ehrenberg
has been able to discover.

The theories of this great naturalist are fully deseribed in
Mr. Pritchard’s work.

Dr. Pouchet, who to some extent supports Ebrenberg’s
opinion, acknowledges the existence of the polygastric struc-
ture, so far as the fixed globular stomachs are concerned, but
candidly confesses that he has not been able to discover a
connecting bowel. He has chiefly studied the Kolpoda and
Vorticelle.

Opposed to this theory, Dujardin affirms that the so-called
Polygastrica contain irregularly-formed alimentary granules,
which continually rotate within the body, in the same manner
as inthe Chara in Plants ; and that not being fixed, as stated by
Ehrenberg, they cannot have a connecting “bowel attached to
the outer integument.

Dr. Cohn, of Breslau, has accurately described this rotation
of granules in Lozodes bursaria, and contributed an article on
the structure of this Infusorium to Siebold’s ‘ Zeitschrift.’

The following are the results (concisely stated) of my
investigation, in connection with this disputed question.

I have traced the growth of Glaucoma scintillans, from the
Monas socialis of Ehrenberg (found amongst the Chlamido-
monas, or green-dust monads, in rain-water), and have seen
gradually developed within it many simple globular stomachs,
placed in a tolerably regular line round the body. They do
not rotate, but are permanently fixed. I have fed them with

MEMORANDA. 167

indigo ; seen them gradually become filled with that sub-
stance, and afterwards resume their transparent appearance,
as the digested matter was ejected in a stream from the pos-
terior orifice of the animalcule. After careful and repeated
observations, I feel satisfied that no bowel exists (for a blue
line, however faint, would in that case be visible).

This genus is somewhat allied to Kolpoda, the one investi-
gated by Dr. Pouchet; and I can, therefore, confirm his
opinion, with the additional observation, that I have found
each stomach to be provided with a little circular aperture for
the admission of food.

This does not, however, invalidate the theory of Dujardin ;
for, after reading Dr. Cobn’s account of the rotation in Lozodes,
I carefully examined Chelodon aureus, a similar type, and
found his observations to be perfectly applicable to this
animalcule, with only one difference, namely, that the granules
take two different directions from one side of the body, and
meeting at the opposite side, are there lost in the general
substance of the body. I have also clearly traced the rotation
of granules in Stentor viridis (S. polymorphus, Ehrenberg).

If these observations be correct, it follows that the two
parties before alluded to have examined two different types.

Dr. Pouchet (for Ehrenberg’s theory is too sweeping) has
studied, and accurately described, the structure of Kolpoda,
Vorticella, &c. ; whilst Dujardin, Cohn, and others, have
correctly observed Chelodon, Loxodes, Nassula, and that type
of Animalcule.

My investigations were made with a good, clearly-defining
microscope, manufactured by Schieck, of Berlin, and with
powers varying from 200 to 900 diameters.—JamEs SAMUEL-

son, full.

( 168 )

PROCEEDINGS OF SOCIETIES.

Microscoricay Society, March 28, 1855.
Dr. CarPenTER in the chair.
Geo. Bishop, jun., Esq., was balloted for and duly elected a
member of the Society.
The Society then adjourned to a soirée.

April 25, 1855.
Dr. CARPENTER in the chair.

E. G. Lobb, Esq., and J. Le Capellain, Esq., were balloted for,
and duly elected members of the Society.

A paper by Mr. Farrants on Mr. Peters’ Writing Machine was
read (Transactions, vol. iii. p. 55).

A paper by Mr. Furze on the Illumination of Objects by Polarized
Light was read (Transactions, vol. iii. p. 63).

The President made some remarks on the Structure of the Animal
of the Foraminifere.

May 23, 1855.
Dr. CARPENTER in the chair.

Mr. R. Tootal, Esq., W. C. Jones, Esq., C. H. Hingeston, Esq.,
and Capt. W. Noble, were balloted for, and duly elected members.

Mr. Warington read a paper on a new portable form of micro-
scope.

The President made some observations on Foraminifere.

June 25, 1855.
Dr. CARPENTER in the chair.

Rev. Jas. Guillemard, Bournemouth; J. M. Burton, Esq., Lee
Park; F. Currey, Esq., Blackheath Park, were balloted for, and
duly elected.

The following communications were read.

On three new species of Rotifers, and a microscopic plant, found
in India by J. Mitchell, Esq., Bangalore.

On the Circulation in Anacharis Alsinastrum by Dr. Branson
and Mr. Wenham. (Vol. ILI. ‘ Journal of Microscopical Science,’
pp. 274-277.)

The President described two low-priced microscopes, which had
obtained the prize at the Society of Arts. The instruments were
also exhibited. (Vol. III. ‘Journal of Microscopical Science,’
p. 306.)

October 31, 1855.
Dr. CARPENTER in the chair.

F. H. Glossop, Esq., Spring Grove, Isleworth; W. Heslop, Esq.,
St. John’s-street, and M. Bland, Esq., Fleet-street; were balloted
for, and duly elected members of the Society.

A paper by E. G. Lobb, Esq., on Anacharis Alsinastrum was
read.

The President gave an account of certain proceedings at the
British Association.

PROCEEDINGS OF SOCIETIES. 169

November 28, 1855.
GerorGE Jackson, Esq., in the chair.

C. L. Bradley, Esq., Barnsbury Park; E. Grove, Esq., Park-
street, Westminster ; E. Cobbett, Esq., 4 Cullum-street; Mr. H.
Williams, Somerset House; and John White, Esq., Cowes, Isle of
Wight, were balloted for, and duly elected.

Mr. Wenham read a paper on the formation and development of
Vegetable Cells (Transactions, vol. iv. p. 1).

Royau Society.

Mr. Gossr, ‘“ On the Structure, Functions, and Homology of the
Manducatory Organs in the Class Rotifera.’ March 1, 1855.
In this paper the author institutes an examination of the manduca-
tory organs in the class Rotifera, in order to show that the various
forms which they assume can all be reduced to a common type. He
further proposes to inquire what are the real homologues of these
organs in the other classes of animals, and what light we can
gather, from their structure, on the question of the zoological rank

of the Rotifera.

After an investigation of the bibliography of the class from Ehren-
berg to the present time, in which the vagueness and inexactitude
of our knowledge of these organs is shown, the author takes up, one
by one, the various phases which they assume throughout the whole
class, commencing with Brachionus, in which they appear in the
highest state of development. Their form in this genus is therefore
taken as the standard of comparison.

The hemispherical bulb, which is so conspicuous in B. amphiceros,
lying across the breast, and containing organs which work vigorously
against each other, has long been recognized as an organ of mandu-
cation ; it has been called the gizzard, but the author proposes to
distinguish it by the term mastax. It is a trilobate muscular sac,
with walls varying much in thickness, receiving at the anterior ex-
tremity the buccal funnel, and on the dorsal side giving exit to the
esophagus.

Within this sac are placed two geniculate organs (the madllei),
and a third on which they work (the izeus). Each malleus consists
of two parts (the manubrium and the uncus), united by a hinge-
joint. The manubrium is a piece of irregular form, consisting of
carine of solid matter, enclosing three areas, which are filled with
a more membraneous substance. The uneus consists of several
slender pieces, more or less parallel, arranged like the teeth of a
comb, or like the fingers of a hand.

The ineus consists of two ramz, which are articulated by a com-
mon base to the extremity of a thin rod (the fulerum), in such a
way that they can open and close by proper muscles. The fingers
of each wneus rest upon the corresponding ramus, to which they are
attached by an elastic ligament. The mallet are moved to and fro
by distinct muscles, which the author describes in detail, and by the
action of these they approach and recede alternately; the rami
opening and shutting simultaneously, with a movement derived
partly from the action of the mallet, and partly from their own
proper muscles,

170 PROCEEDINGS OF SOCIETIES.

All these organs have great solidity and density; and, from the
action of certain menstrua upon them, appear to be of calcareous
origin.

The writer proceeds to describe the accessory organs. The
ciliated dise has an infundibuliform centre, which commonly merges
into a tube before it enters the mastax. The particles of food that
float in the water, or swimming animalcules, are whirled by the
ciliary vortex into this tube, and being carried into the mastax are
lodged upon the ram, between the two unci. These conjointly
work upon the food, which passes on towards the tips of the ram,
and enter the cesophagus, which opens immediately beneath them.

From this normal condition, the author traces the manducatory
organs through various modifications in the genera Huchlanis,
Notommata aurita, N. clavulata, Anurea, N. petromyzon, N. laci-
nulata, Fureularia, N. gibba, Syncheta, Polyarthra, Diglena,
Eosphora, Albertia, F. marina, Asplanchna, Mastigocerea, Mono-
cerca, and Scaridium. Some of these display peculiarities and
aberrations highly curious. Notwithstanding the anomalies and
variations which occur, however, the same type of structure is seen
in all; and the modifications in general may be considered as suc-
cessive degenerations of the madlei, and augmentations of the ineus.

The form of the mandueatory organs, which occurs in Triarthra,
Pompholyx, Pterodina, Gicistes, Limnias, Melicerta, Conochilus,
Megalotrocha, Lacinularia, and Tubicolaria, is next examined.
The organs are shown to be essentially the same as in the former
type, but somewhat disguised by the excessive dilatation of the
mallei, and by the soldering of the wct and the rami together, into
two masses, each of which approaches i in figure to the quadrant of a
sphere.

Atteution is then directed to what has been called (but by a mis-
apprehension) the “ stirrup-shaped” armature of the genera Rotifer,
Philodina, Actinurus, &c. Here, however, the organs are proved
to have no essential diversity from the common type; their analogy
with those last described being abundantly manifest, though they
are still further disguised by the obsolescence of the manubria.

Flosculuria and Stephanoceros, the most elegant, but the most
aberrant forms of Rotifera, close the series. The mastax, in these
yenera, is wanting; and in the former genus the imews and the
manubria are reduced to extreme evanescence, though the two-fin-
gered wnci show in their structure relative position and action, the
true analogy of these organs.

Having thus shown that there is but oue model of structure, how-
ever modified or disguised, in the mandueatory organs of the Roti-
fera, the author proceeds to the question of their homology. He
argues on several grounds that they have no true affinity with the
gastric teeth of the Crustacea, though he states his conviction that
the Rotifera belong to the great Arthropodous division of animals.

It is with the Insecta that the author seeks to ally these minute
creatures; and, by a course of argument founded on the peculiarities
of structure already detailed, he maintains the following identifiea-
tions :—that the mastax is a true mouth; that the mallet are man-

PROCEEDINGS OF SOCIETIES. 171

dibles ; the manubria possibly representing the cheeks, into which
they are articulated ; that the rami of the ineus are maxille ; and
that the fulerum represents the cardines soldered together.

While the author maintains the counexion of Rotifera with
Insecta, through these organs in their highest development, he
suggests their affinity with Polyzoa, by the same organs at the
opposite extremity of the scale, since the oval muscular bulbs in
Bowerbankia, which approach and recede in their action on food,
seem to represent the quadriglobular masses of Limnias and Rotifer,
further degenerated.

If this affinity be correctly indicated, the interesting fact is appa-
rent, that the Polyzoa present the point where the two great parallel
divisions, Mollusca and Articulata, unite in their course towards
the true Polypi.

Mr. Gosse’s paper is illustrated by ninety-six figures of entire
Rotifera, or of the parts under review, all drawn from the life, and,
for the most part, with a power of 560 diameters.

“ Researches on the Foraminifera.—Part I. General Introduction,
and Monograph of the Genus Orbitolites.” | By Wititam B.
CarrenTer, M.D., F.R.S., F.G.S., &e. Received May 21,
1855.

THe group of Foraminifera being one as to the structure and

physiology of which our knowledge is confessedly very imperfect,

and for the uatural classification of which there is consequently no
safe basis, the author has under‘aken a careful study of some of its
chief typical forms, in order to elucidate (so far as may be possible)
their history as living beings, and to determine the value of the
characters which they present to the systematist. In the present
memoir, he details the structure of one of the lowest of these types,

Orbitolites, with great minuteness; his object having been, not

merely to present the results of his investigations, but also to

exhibit the method by which they have been attained; that method
essentially consisting in the minute examination and comparison of

a large number of specimens.

The Orbitolite has been chiefly known, until recently, through the
abundance of its fossil remains in the Eocene beds of the Paris
basin ; but the author, having been fortunate enough to obtain an
extensive series of recent specimens, chiefly from the coast of
Australia, has applied himself rather to these as his sources of
information ; especially as the animals of some of them have been
sufficiently well preserved by immersion in spirits, to permit their
characters to be well made out.

As might have been anticipated from our knowledge of their con-
geners, these animals belong to the Ahizopodous type ; the soft body
consisting of sarcode, without digestive cavity or organs of any
kind; and being made up of a number of segments, equal and
similar to each other, which are arranged in concentric zoues round
a central nucleus. This body is invested by a calcareous shell, in
the substance of which no minute structure can be discerned, but
which has the form of the circular disk, marked on the surface by

172 PROCEEDINGS OF SOCIETIES.

concentric zones of closed cells, and having minute pores at the
margin. Starting from the central nucleus,—which consists of a
pear-shaped mass of sarcode, nearly surrounded by a larger mass
connected with it by a peduncle,—the development of the Orbitolite
may take place either on a simple, or upon a complex type. In the
former (which is indicated by the ctreular or oval form of the cells,
which show themselves at the surfaces of the disk, and by the single-
ness of the row of marginal pores), each zone consists of but a single
layer of segments, connected together by a single annular stolon of
sarcode ; and the nucleus is connected with the first zone, and each
zone with that which surrounds it, by radiating peduncles proceeding
from this annulus, which, when issuing from the peripheral zone, will
pass outwards through the marginal pores, probably in the form of
pseudopodia. In the complex type, on the other hand (which is
indicated by the narrow and straight-sided form of the superficial
cells, and by the multiplication of the horizontal rows of marginal
pores), the segments of the concentric zones are elongated into
vertical columns with imperfect constrictions at intervals ; instead of
a single annular stolon, there are two, one at either end of these
columns, between which, moreover, there are usually other lateral
communications; whilst the radiating peduncles, which connect one
zone with another, are also multiplied, so as to lie in several planes.
Moreover, between each annular stolon and the neighbouring sur-
face of the disk, there is a layer of superficial segments, distinct from
the vertical columns, but connected with the annular stolons ; these
occupy the narrow elongated cells just mentioned, which constitute
two superficial layers in the disks of this type, between which is the
intermediate layer occupied by the columnar segments.

These two types seem to be so completely dissimilar, that they
could scarcely have been supposed to belong to the same species ;
but the examination of a large number of specimens shows, that
although one is often developed to a considerable size upon the
simple type, whilst another commences even from the centre upon
the complex type, yet that many individuals which begin life, and
form an indefinite number of annuli, upon the simple type, then take
on the more complex mode of development.

The author then points out what may be gathered from observa-
tion and from deduction respecting the Nutrition and mode of
Growth of tuese creatures. He shows that the former is probably
accomplished, as in other Rhizopods, by the entanglement and draw-
ing in of minute vegetable particles, through the instrumentality of
the pseudopodia; and that the addition of new zones probably takes
place by the extension of the sarcode through the marginal pores,
so as to form a complete annulus, thickened at intervals into seg-
ments, and narrowed between these into connecting stolons, the
shell being probably produced by the calcification of their outer
portions. And this view he supports by the results of the examina-
tion of a number of specimens, in which reparation of injuries has
taken place. Regarding the Reproduction of Orbitolites, he is only
able to suggest that certain minute spherical masses of sarcode, with
which some of the cells are filled, may be gemmules ; and that other

PROCEEDINGS OF SOCIETIES. 175

bodies, enclosed in firm envelopes, which he has more rarely met
with, but which seem to break their way out of the superficial cells,
may be ova. But on this part of the inquiry, nothing save observa-
tion of the animals in their living state can give satisfactory results,

The regular type of structure just described is subject to numerous
variations, into a minute description of which the author next enters ;
the general results being, that neither the shape nor dimensions of
the entire disk, the size of the nucleus or of the cells forming the
concentric zones, the surface-markings indicating the shape of the
superficial cells, nor the early mode of growth (which, though
typically cyclical, sometimes approximates to a spiral), can serve as
distinctive characters of species ; since, whilst they are all found to
present most remarkable differences, these differences, being strictly
gradational, can only be considered as distinguishing izdividuals.
It thus follows that a very wide range of variation exists in this
type; so that numerous forms which would be unhesitatingly ac-
counted specifically different, if only the most divergent examples
were brought into comparison, are found, by the discovery of those
intermediate links which a large collection can alone supply, to
belong to one and the same specific type.

After noticing some curious monstrosities, resulting from an un-
usual out-growth of the central nucleus, the author proceeds to in-
quire into the essential character of the Orbitolite, and its relations
to other types of structure. He places it among the very lowest
forms of Foraminifera ; and considers that it approximates closely
to sponges, some of which have skeletons not very unlike the cal-
careous net-work which intervenes between its fleshy segments. Of
the species which the genus has been reputed to include, he states
that a large proportion really belong to the genus Orbitoides, whilst
others are but varieties of the ordinary type. This last is the light
in which he would regard the Orbitolites complanata of the Paris
basin; which differs from the fully-developed Orbitolite of the
Australian coast in some very peculiar features (marking a less com-
plete evolution), which are occasionally met with among recent
forms, and which are sometimes distinctly traditional towards the
perfect type.

“* Notes on British Foraminifera.” By J. Gwyn JEFFREYS, Esq.,
F.R.S. Received June 19, 1855.

Havine, during a great many years, directed my attention to the
recent Foraminifera which inhabit our own shores, I venture to offer
a few observations on this curious group, as Dr. Carpenter, who has
favoured the Society with an interesting and valuable memoir on
the subject, seems not to have had many opportunities of studying
the animals in the recent state.

Rather more than twenty years ago I communicated to the Lin-
nean Society a paper on the subject, containing a diagnosis and
figures of all the species. ‘This paper was read and ordered to be
printed in the Transactions of that Society; but it was withdrawn
by me before publication, in consequence of my being dissatisfied
with D’Orbigny’s theory (which I had erroneously adopted), that

174 PROCEEDINGS OF SOCIETIES.

the animals belonged to the Cephalopoda; and my subsequent ob-
servations were confirmed by the theory of Dujardin. I have since
placed all my drawings and specimens at the disposal of Mr. Wil-
liamson, of Manchester, who has given such good earnest of what
he can do in elucidating the natural history of this group, by his
papers on Lagena and the Foraminiferous mud of the Levant.

The observations which I have made on many hundred recent and
living specimens of various species, fully confirm Dr. Carpenter’s
view as to the simple and homogeneous nature of the animal. His
idea of their reproduction by gemmation is also probably correct;
although I cannot agree with him in considering the granules which
are occasionally found in the cells as ova. These bodies I have fre-
quently noticed, and especially in the Lagene ; but they appeared
to constitute the entire mass, and not merely a part of the animal.
I am inclined to think they are only desiccated portions of the ani-
mal, separated from each other in consequence of the absence of any
muscular or nervous structure. It may also be questionable if the
term ‘‘ova” is rightly applicable to an animal which has no distinet
organs of any kind. Possibly the fry may pass through a metamor-
phosis, as in the case of the Medusa.

Most of the Foraminifera are free, or only adhere by their pseudo-
podia to foreign substances. Such are the Lagena of Walker, Wodo-
saria, Vorticilais and Textularia, and the Miliola of Lamack. The
latter has some, although a very limited, power of locomotion ; which
is effected by exserting its pseudopodia to their full length, attach-
ing itself by them to a piece of seaweed, and then contracting them
like india-rubber, so as to draw the shell along with them. Some
of the acephalous mollusks do the same by means of their byssus.
This mode of progression is, however, exceedingly slow ; and I have
never seen, in the course of twenty-four hours, a longer journey than
a quarter of an inch accomplished by a Miliola, so that, in compari-
son with it, a snail travels at a railroad pace.

Some are fixed or sessile, but not cemented at their base like the
testaceous annelids. The only mode of attachment appears to be a
thin film of sareose. ‘The Lobotula of Fleming, and the Rosalia and
Planorbulina of D’Orbigny belong to this division.

Dr. Carpenter considers the Foraminifera to be phytophagous, in
consequence of his having detected in some specimens, by the aid of
the microscope, fragments of Diatomacee and other simple forms of
vegetable life. But as I have dredged them alive at a depth of
108 fathoms (which is far below the Laminarian zone), and they are
extremely abundant at from 40 to 70 fathoms, ten miles from land
and beyond the range of any seaweed, it may be assumed without
much difficulty, that many, if not most of them, are zoophagous, and
prey on microscopic animals, perhaps even of a simpler form and
structure than themselves. ‘They are in their turn the food of mol-
lusea, and appear to be especially relished by Dentalium Entale.

With respect to Dr. Carpenter’s idea that they are allied to
sponges, I may remark that Polystomella crispa (an elegant and not
uncommon species) has its periphery set round at each segment with
siliceous spicula, like the rowels of'a spur. But as there is only one

PROCEEDINGS OF SOCIETIES. 175

terminal cell, which is connected with all the others in the interior
by one or more openings for the pseudopodia, the analogy is not
complete, this being a solitary, and the sponge a compound or
aggregate animal.

I believe the geographical range or distribution of species in this
group to be regulated by the same laws as in the Mollusks and other
marine animals. In the gulf of Genoa I have found (as might have
been expected) species identical with those of our Hebridean coast,
and vice versa.

In common with Dr. Carpenter, I cannot help deploring the ex-
cessive multiplication of species in the present day, and I would in-
clude in this regret the unnecessary formation of genera. Another
Linneeus is sadly wanted to correct this pernicious habit, both at
home and abroad.

The group now under consideration exhibits a great tendency to
variation of form, some of the combinations (especially in the case of
Marginulina) being as complicated and various as a Chinese puzzle.
It is, I believe, undeniable, that the variability of form is in an in-
verse ratio to the development of animals in the scale of Nature.

Having examined thousands (I may say myriads) of these elegant
organisms, I am induced to suggest the following arrangement :—

1. Lagena (Walker) and Extosolenia (Williamson),

2. Nodosaria and Marginulina (D’Orb.), &e.

3. Vorticialis (D’Orb.), Rotalia (Lam.), Lobatula (Flem.),
Globigerina (D’Orb.), &e.

4. Textularia (Defrance), Uvigerina (D’Orb.), &e.

5. Miliola (Lam.), Biloculina (D’Orb.), &e.

This division must, however, be modified by a more extended and
cosmopolitan view of the subject, as I only profess to treat of the
British species. ‘To illustrate MacLeay’s theory of a quinary and
circular arrangement, the case may be put thus.

The first family is connected by the typical genus Lagena with
the second, and by Extosolina with the fifth ; the second is united
with the third through Marginulina; the third with the fourth
through Globigerina ; and the fourth with the last through Uvige-
rina.

Whether these singular and little-known animals are Rhizopodes,
or belong to the Amceba, remains yet to be satisfactorily made out.

London, June 18, 1855.

(“41976>.)

ZOOPHYTOLOGY.

Tue species of Polyzoa here described, and most of which
appear to be new, occurred on shells from Mazatlan, on the
Gulf of California; and for the opportunity of examining
them, I have been indebted to the kindness of Mr. Phillip
Carpenter, who has prepared a descriptive catalogue of the
“¢ Mazatlan Mollusca,” for the British Museum. The typical
specimens of the forms here noticed, will be found in that
Institution.

Order. PoLyzoA INFUNDIBULATA.

Sub-order I. CHEILOSTOMATA.
Fam, Mrmpranriporipm.
Gen. 1. Membranipora, Blainv.
1. M. denticulata (n. sp.), Busk. Pl. VII., figs. 1 and 2.

Area of cells rhomboidal ; internal margin of the aperture denticulate ;
cells separated by a narrow raised line.

Hab. Mazatlan: on the shells of Zmperator olivaceus, I. unguis, and
Anomia.

The outline of the cells is usually distinctly defined by a
narrow brown line. One or two rounded or triangular emi-
nences (probably ovicells) are visible on many of the cells in
front and below. The form bears considerable resemblance
to M. Savartii, (Savigny, Egypt, pl. 10; M. Laeroizxii,
Savigny, B. M. Cat., p. 60, Plate 104, fig. 1,) but differs from
it in several important respects ; among which may be noticed
a narrow brown line surrounding the cells, and clearly defining
one from the other; and the irregularly shaped branching
denticles with which the margin of the internal aperture is
furnished.

2. M. gothica, n. sp., Rylands, MS. Pl. VIL, fig. 5, 6, 7.

Area of cells elongated, oval; margin thin and smooth; mouth raised,
suborbicular, with an ovide notch inferiorly; the anterior, calcareous,
depressed surface of the cells punctated, and perforated on each side by a
wide aperture ; large, immersed avicularia scattered irregularly over the
polyzoary.

Hab. Mazatlan: on Imperator olivaceus and unguis.

There is occasionally a short blunt spine or process on
each side of the mouth, a character which is also presented in
M. Rozieri, Savig. (B. M. Cat., p. 59, Plate 65, fig. 6) a
species to which the present exhibits, in other respects, con-
siderable resemblance, and especially in the existence of the
large opening on each side of the front of the cells immedi-
ately below the mouth. The differences between the two,
however, are sufficiently striking. In MZ. Rozieri the ovicell

ZOOPHYTOLOGY. 177

is large, superior, rounded, and carinate in front, whilst in MW.
gothica, as in M. calpensis, Busk. B. M. Cat., p. 60, Plate 104,
fig. 5, 6, this organ appears to be represented by one or two
rounded eminences at the bottom of the cell in front. The
large scattered avicularia also are characteristic of the present
form, as well as its far larger size.

The same species occurs on a Pearl-oyster shell, for which
I am indebted to Dr. J. E. Gray, the habitat of which seems
to be doubtful. In M, Milne Edward’s Memoir “Sur les
Eschares,” p. 17, Plate 12, fig. 13, a miocene fossil is
described and figured, which bears some resemblance to the
present; it differs principally, so far as can be determined

from the figure alone, in the thickened and granulated margin
of the area.

3. M. ,n.sp.? Pl. VIL, fig. 3, 4.

Apparently an undescribed form, but requiring further research for its
precise determination.

Hab. As the preceding.
Gen. 2. Lepralia, Johnston.

1. L. marginipora, Reuss. Fossil. Polyp. d. Wiener tertiar. Becken.,

p. 88." PI, 10;, fig, 2a. Busk, 1. ¢;.
p. 4.

Cells ovate, convex or slightly depressed, immersed, roughish, punctate
at the margin; mouth round, or subelliptical; margin thickened, with
an avicularium on each side,

Hab. Mazatlan: on Imperator unguis ; Vienna tertiary basin (fossil) ?

As the form appears precisely to resemble the tertiary
species described and figured by Reuss, I have applied his
name to it, and in great part employed his character.

2. L. humilis, n. sp. Busk, l.c., p.5. Pl. VIIL., fig. 1.

Cells immersed, depressed, or flattened, surface obscurely punctate ;
mouth small, rounded, with a shallow sinus in the lower lip, margin
simple, thin.

Hab. Mazatlan: on Imperator unguis.

3. L. hippocrepis,n. sp. Busk, l.c., p. 4. Pl. VIIL., fig. 2.
Cells immersed, punctate ; mouth suborbicular or elliptical, its upper

margin in the older cells inconspicuous, inferiorly and laterally, thickened
with an avicularium on each side.

Hab. Mazatlan: on Imperator olivaceus.

The peculiar horse-shoe shaped mouth of the older cells,
with the avicularia on either side, sufficiently distinguishes
the present from L. marginipora, to which, in the mouth of
the younger cells, it bears some resemblance.

4, L. Mazatlanica, n. sp. Busk, |. c., p. 38. Pl. VIL, fig. 4.

Cells immersed, depressed, or ventricose; surface punctate; mouth
VOL. IV. N

178 ZOOPHYTOLOGY.

suborbicular, with a wide sinus in the lower lip ; margin thickened, raised ;
a single avicularium (more rarely two) on the side near the mouth.

Hab. Mazatlan: on Imp. olivaceus and unguis.

This form might easily be confounded with some varieties
of L. unicornis, or L. Ballii (B. M. Cat.) It is distinguished,
however, by its reddish colour, and the raised mouth, together
with its thickened margin. The single, or sometimes double
avicularium, points outwards and upwards, and the mandible
is prolonged and acute. This organ is sometimes, but not
often absent.

5. L. adpressa, Busk. (B. M. Cat., p. 82. Pl. CII., fig. 3, 4.)

Hab. Mazatlan: on Columbella major, C. fuscata, and Pisania gemmata,
not uncommon. Chiloe, 96, fm. Shell ; Darwin.

The Mazatlan form differs from that from which the former
description and figure were taken, in the absence, or indis-
tinctness rather, of the radiating grooves. In other respects
the two agree very closely.

6. L. atrofusca, Rylands, MS.

Cells elongated, ovate or rhomboidal, bordered with a thin elevated line,
surface punctate ; mouth suborbicular, sinuated in the lower lip, toothed
on each side.

Hab. Mazatlan: on Jmper. olivaceus and unguis, and on Anomia.

General hue blackish ; and even when the cells are more
calcareous, and on that account whiter, the dark interstitial
line remains very evident. It is quite distinct from ZL. cucul-
lata (B. M. Cat., p. 81, Plate 96, fig. 4, 5) which is also of a

black colour, and occurs in the Mediterranean.

7. L. trispinosa, Johnston. (B. M. Cat., p. 70. Pl. 85, fig. 1, 2.
Pl. 57, fig. 7.)
Hab. Mazatlan: on Imperator? Britain,

A single minute specimen only occurred, but this is quite
undistinguishable from the British form.

8. L. rostrata, n. sp. Busk, 1. ¢., p. 4

Cells immersed, surface tuberculous or granulous ; mouth immersed,
upper margin inconspicuous ; lower lip deeply grooved, armed with a large
sessile avicularium,

Hab. Mazatlan: on Jmp. unguis.

The lower margin of the mouth, in the mature cells, is
deeply grooved in the middle; and on one side of the groove
is a strong, short, blunt spinous process; and on the other a
comparatively large, raised avicularium, which looks towards
the sulcus, and whose mandible is acute, and points upwards
and outwards. The surface of the cell is often beset with
short raised spines or processes ; and these projecting over the

ZOOPHYTOLOGY. L79

mouth of the cell beneath, give it the appearance of being
furnished with several oval spines.

Gen. 3. Cellepora, O. Fabricius.
1. C. papilleformis, n. sp., Busk, l. c., p.5. Pl. VIIL, fig. 5.
Cells sub-hexagonal, raised, surface punctate ; mouth suborbicular, with
a tooth on each side, margin simple, thin; scattered avicularia, with a
triangular mandible.

Hab. Mazatlan: on Jmp, olivaceus.

A well-marked and distinct form belonging to that sub-
division of Cellepora in which the mouth is not armed with a
projecting avicularium. The top of each cell projects in the
form of a rounded mamillary eminence from a_ hexagonal
area, which defines the border of the cell. The cells are of
very unequal size, and very irregularly disposed. It is of a
brownish colour.

2. C. cyclostoma, n. sp., Busk, 1. c., p. 5. Pl. VIIL., fig. 3. a, b, c.
Cells suberect or decumbent, discrete ; surface punctate; mouth large,
rounded above, with a wide sinus in the lower lip; the margin in the
older cells much raised, thickened, occasionally dilated, infundibuliform,
and furnished with a minute avicularium on each side,

Hab. Mazatlan: on Imp. unguis.

The wide, rounded, or elliptical, raised margin of the
mouths of the distant cells, gives the polyzoarium of the
present species a very peculiar and well-marked aspect. It is
of a brownish hue or white.

Sub-order II. CycLostomata.
Fam. Discoporap#@, Busk, MS.
Gen. Defrancia, Brown.
1. D. intricata, n. s., Busk, 1. ¢., p. 6.
Disc very irregular in form, rows of cells radiating irregularly ; orifices
of cells and intersticial pores of equal size.
Hab. Mazatlan: on Imperator unguis.

The small irregular patches appear to be constituted by the
confluence of several sets of coste, with their corresponding
interstices, each set radiating from a depressed central point.
It differs from D. deformis, Reuss (op. cit. p. 36, Plate 5, fig.
24), in the uniform size of the openings of the tubes in the
costa, and of the pores in the interstices.

Besides the above, there occur on some of the shells in the
same collection, indications of other species, but in too im-
perfect a condition to allow of their determination with any
certainty. Among these, perhaps the best marked are a
species strongly resembling Cellepora pumicosa, Linn., a species

of Lepralia, and a Tubulipora.

ZOOPHYTOLOGY.

DESCRIPTION OF FIGURES.

Puate VII.
Fig.
1, 2.—Membranipora denticulata.
3, 4.—Membranipora sp. ?
5, 6, 7.—M. gothica.
8.—Lepralia marginipora.

Puate VIII.

1.—Lepralia humilis.
2.—L. hippocrepis.
3.—Cellepora cyclostoma.
4.—L. Mazatlanica.
5.—Cellepora papilleeformis.
6.—L. adpressa.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE III,

Illustrating Pringsheim’s paper on the Impregnatiou and
Germination of Alge.

Figs. 1 to 20, Vaucheria sessilis, multiplied 250 diameters.

1 to 4.—Stages of development of the sexual organs before impregnation.

5.—The sexual organs during impregnation.

6 to 8.—The way in which the female organ (the so-termed ‘‘ spore”)
opens, the ‘‘ cutaneous layer” bursts through, and a portion is
constricted off.

9.—Approach of the spermatozoids to the female organ before the forma-
tion of the membrane of the embryo-cell (the true spore).

10.—The point of the female sexual organ after the formation of the
membrane of the true spore.

11, 12.—Later condition of the spore, after impregnation.

13 to 16.—Later condition of the male and female organs after impregna-
tion. They show the subsequent slow detachment of the mem-
brane of the male organ (the antheridiwm formed out of the
summit of the ‘“hornlet”), and the gradual decoloration of the
contents of the spore, lying in the female sexual organ (the spo-
rangiwm).

17.—Colourless spore after it has become detached from the parent tube.

18.—A spore detached from the tube, which after long rest (three months)
has again become green ; an indication of its awakening develop-
ment.

19, 20.—Germination of the viridescent spores.

Figs. 21 to 24, Fucus vesiculosus, multiplied 200 diameters.
21.—Large spore (sporangivm), whose contents the eight still connected
“‘ division spores” have escaped.

22,—“ Division spores,” isolated before impregnation ; the clear central
spot shows the true cell-cavity filled merely with fluid.

23.—Division spore after impregnation. The spermatozoids may be seen
within the membrane.

24.—Earlier state of germination of an impregnated ‘ division spore.”
Fig. 25, Sphacelaria tribuloides, multiplied 3500 diameters.

25.—Propagative gemmule, whose terminal cell transformed into a
Sphacela contains an antheridium partly emptied and partly filled
with spermatozoids.

Figs. 26, 27, @dogonium tumidulum, roultiplied 350 diameters.

26, 27.—Sporangium during (fig. 26) and after (fig. 27) the formation
of the micropyle for the spermatozoids.

Figs. 28 to 84, Bulbochcete, multiplied 250 diameters.
28.—Sporangium of Bulbochete setigera ; the passage into the interior of
the sporangium is already formed by a transverse fissure of the
membrane. <A microgonidium has germinated upon the spo-
rangium, and discharged its contents.

29.—A similar condition in a sporangium of B. crassia (n. sp.)

30, 31.—Sporangia of B. intermedia, ruptured in consequence of the
incipient development of the spore. ‘The spore, covered only by the
innermost layer of the cell-wall, has escaped from the sporangium.

32.—The liberated spore is somewhat elongated, and

33.—Its contents divided into four portions.

34,—The division is completed ; the four reddish green zoospores, produced
from the contents of the quiescent spore, are already fully formed,

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JOURNAL OF MICROSCOPICAL SCIENCE.

Fig.

DESCRIPTION OF PLATE VL,

Illustrating Mr. Tomes’s paper on Dental Tissues.

1.—A section from a temporary tooth, in which the dentine (a) and the

2.—A

enamel (5) have been removed by absorption, leaving the festooned
outline (¢).

section from the fang of a tooth, in which the dentine (a) has
been removed, together with the cementum (c), and again made
good by the deposition of cementum. The appearance presented at
the junction of the dentine and cementum, where absorption has
not encroached upon the tissues at that point, is shown at (0),
The curved irregular lines in the cementum indicate the extent of
absorption at various periods, and the boundaries of the tissue
which has replaced the lost parts.

3.—A section from a temporary tooth, the fangs of which have been

absorbed, and the crown hollowed out; the enamel having been
partly removed, and both tissues coated over with new cementum.
(a), the dentine ; (6), the enamel; (c), the cementum; (d), the
junction of the absorbed surface of the enamel and new cementum.

4.—A section of enamel, in which the centre (a) has been ground

through ; (0), the enamel fibres, with their granular cells shown
faintly ; (cc), the sheaths of the enamel fibres.

5.—A more highly magnified view from the same specimen, showing the

sheaths of the enamel fibres and their contents.

6,—A transverse section of enamel, showing the sheaths of the fibres

with the contents removed.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE VIL,

Illustrating Mr. Brightwell’s paper on Chetoceros, and some
allied forms.

Fig.

1 and 2.—C. Bacillaria? Bailey.

3 to 7.—C. didymum, Ehr. 5*, side view.

8.—C. gastridium, Ehr.

9 to 11—C. incurvum, Bailey. 11, Dr. Bailey’s figure reduced, equal
200 diam.

12 to 15.—@. boreale, Bailey. 12 to 14 are copied from Dr. Bailey’s
figures. 13, side view, red, equal 100. 15, from our own
specimens in all of which a slight constriction is visible
near the inner margin of the frustule; the horns run straight
out at a right angle to the frustule. :

16 to 18.—C. Peruvianum (n. sp.).

19 to 36.—C. Wighamii (n. sp.) 19 to 27 represent varieties in form and
character of processes of the contained goniothecium-like
frustules, from widely distant localities. 29 and 30 show
the neck separating. 380, the cup-shaped portion without
the neck, equal Omphalotheca hispida, Ehr. 82, side view.
33, a filament in its recent state drawn, in water with the
Endochrome. 34, short filament with internal frustules
irregularly placed. 385, side view of entire frustule. 36,
cingulum and horns without the frustule.

37.—C. hispidum, Ehr.

38.—C. navicula, Ehr.

39 to 42.—C. barbatum? Ehr.

43 to 46.—Goniothecium Rogersti, Ehr. 46, side view.

47 and 48.—G. Odontella, Ehr.

49 to 52.—Syndendrium diadema, Ehr. 52, side view.

53 to 60.—Diocladia Capreolus in different stages of growth. 54, shows
the membrane, not unfrequently found adhering to the horns.
56, a side view. 58, frustules like this have probably given
origin to Ehrenberg’s Goniothecium didymum. 59, 60,
varieties.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE VIII.,

| Illustrating Mr. Hepworith’s paper on the Mandibles of Acaride.

Fig.
1.—A portion of human skin, including an itch pustule ; 48 diameters.
a, ova of Acarus Scabiet.
b, young insects.
c, effete matter deposited by insects. .
2.—Full-grown insect, Acarus Scabiei ; 65 diameters.

3.—Mandible of ditto; 890 diameters.

4,— Pe of Acarus Sacchari (female) ; 390 diameters.
5.— 35 of ee (male); 390 diameters.
6.— 35 of Acarus of domestic Fly ; 630 diameters.
7.*— ,, of Long-legged Spider ; 30 diameters.
8.— Ps of Acarus of Blue Beetle and Humble Bee.
94— ,, of Cheese Mite; 390 diameters.
10.— » of Chelifer cancroides ; 65 diameters.
lla.— _ ,, of parasite of Mole ; 240 diameters.
b, proboscis ; 240 diameters.
12.— » of another parasite of Mole; 240 diameters.
13.— 55 of parasite of Rabbit ; 240 diameters.

14.—Mandibles of parasite of Water Rat ; 200 diameters.

* Perhaps, instead of calling these mandibles, they would more properly come
under the term maxillary palpi; as in the Scorpion. It appears to be one of the
non-spinning Arachnidans, If a leg get accidentally torn off, there is a spasmodic
twitching, which continues some seconds in the severed limb. This is so familiar
a phenomenon that there will be little difficulty in recognising the kind of spider I
mean. As I am an inquirer, I shall be glad to see any remarks on the subject.

+ Rymer Jones says (R J.’s ‘Animal Kingdom,’ p. 308), in speaking of the
Acarida, “The mouth seems adapted for suction, and the jaws form a piercing
instrument, barbed at the extremity.’? MNote.—I have not been able to detect this
piercing instrument: it has two powerful mandibles, as seen above, and equally
powerful maxilla; and in action they indicate too much motion, and which is of a
different character to that where suction is accomplished. How could a flour mite
(which has precisely the same kind of apparatus) subsist on dry flour, if it had organs
adapted to suction only ? I can easily conceive how the parasite of the Mole (fig. 11),
with its barbed proboscis, could live by suction.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE IX.,

Illustrating Dr. Thudichum’s paper on Green Pigment
Degeneration of Muscle.

Fig.

1.—Piece of degenerated muscular fibre from wall of left ventricle.
Transverse stri# interrupted by longitudinal lines. Granular
green pigment scattered along the axis of the fibre.

2.—Pieces of fibre with longitudinal lines (the stria have disappeared) ;
a, nucleus, and pigment deposits at both ends of the nucleus;
b, patch of pigment corpuscles, found at equal distances along
a fibre.

3.—Pieces of fibre, much macerated, from the right ventricle. Transverse
strie little indurated. Exhibits the striking difference of true
fat (b) from pigment (a).

4,—Nerve fibril from right septum.

5.—The same after boiling with ether and cooling. The cylinder axis
(serrated) has disappeared, and fat globules are deposited against
the outer membrane of the fibril.

Illustrating Mr. Weston’s paper on Actinophrys Sol.
Fig.
3.—Actinophrys Sol drawn by Camera lucida; a a, two Vorticella en-
closed in a vesicle ; 6, vesicle.

4,—A, Sol in the act of self-division.
5.—A, Sol ; a, an animalcule ; 6 bd, two expanded cells.

6.—Actinophrys ; a, Chetonotus larus engulphed; b 6 b, three Rotifers
caught; c, the valve.

7.—A, Sol seizing a Vorticella ; a, Vorticella.

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ORIGINAL COMMUNICATIONS.

Further Opservations on the SrrucrurE of APPENDICULARIA
Frasettum (Chamisso). By T. H. Houxtey, F.RS.
(Plate X.)

In a paper read before the Royal Society in 1851, I gave an
account of a very singular animal which had been frequently
observed and described under various names, as Appendicu-
laria (Chamisso), Ozkopleura (Mertens), Fritillaria (Quoy and
Gaimard), Vexillaria (J. Miiller), and Eurycercus (Busch),
but whose precise place in the animal kingdom was still a
matter of doubt. The essential points in that account will be
found in the following extracts :—*
* * * *

“<The animal has an ovoid or flask-like body one-sixth to one-fourth of

an inch in length, to which is attached a long curved lanceolate appendage

or tail, by whose powerful vibratory motions it is rapidly propelled through
the water.”

“The smaller extremity of the animal is perforated by a wide aperture
(d) which leads into a chamber, which occupies the greater part of the
body, and at the bottom of this chamber is the mouth. The chamber
answers to the respiratory cavity of the Zunicata, and is lined by an inner
tunic distinct from the outer; the space between these, as in the Salpe,
being occupied by the sinus system.

‘** On the side to which the caudal appendage is attached, an endostyle
(c), altogether similar to that of the Salpe, lies between the inner and
outer tunics; and opposite to this, or on the ventral side, close to the
respiratory aperture, there is a nervous ganglion, to which is attached a
very distinct spherical auditory sac, containing a single, also spherical,
otolithe. he sac is about 1-200th of an inch in diameter. The otolithe
about 1-800th, figs. 1, 2, 4 a.

*¢ Anteriorly, a nerve is given off from the ganglion (a) which becomes
lost about the parietes of the respiratory aperture ; another large trunk
passes backwards (b) over the left side of the cesophagus, and between the
lobes of the stomach, until it reaches the appendage, along the axis of
which it runs, giving off filaments in its course, fig. 2.”

‘There is no proper branchia; but that organ seems to be represented
by a richly-ciliated band or fold (e) of the inner tunic, which extends from
the opening of the mouth forwards, along the ventral surface of the
respiratory cavity, to nearly as far as the ganglion; when it divides into
two branches, one- of which passes up on each side, so as to encircle the
cavity (f). This circlet evidently represents the ‘ ciliated band’ of
Salpa.

«The mouth (g) is wide, and situated at the posterior part of the ventral
parietes of the respiratory chamber. The cesophagus (/) short, and slightly
curved, opens into a wide stomach (7) curved transversely, so as to present
two lobes posteriorly.

* Nova Acta Acad. Curiosorum, t. xi. pars secunda, pp. 313 and 314.
VOL. IV. O

182 HUXLEY, ON APPENDICULARIA FLABELLUM.

“¢ Between the two lobes, posteriorly, the intestine (/) commences, and
passing upwards (or forwards) terminates on the dorsal surface just in
front of the insertion of the caudal appendage (/).

“ The heart lies behind, between the lobes of the stomach. I saw no
corpuscles, and the incessant jerking motion of the attached end of the
caudal appendage rendered it very difficult to make quite sure even of the
heart’s existence.”

“The caudal appendage (A) is attached or rather inserted into the body
on the dorsal surface just behind the anus. It consists of a long, appa-
rently structureless, transparent, central axis (mm), rounded at the attached,
and pointed at the free end. This axis is enveloped in a layer (0) of lon-
gitudinal, striped, muscular fibres; which form the chief substance, in
addition to a layer of polygonal epithelium cells, of the broad alary expan-
sion on each side of the axis.”

“The only unequivocal generative organ I found in Appendicularia
was a testis (p), consisting of a mass of cells developed behind and below
the stomach, enlarging so much in full-grown specimens as to press this
completely out of place.

‘* In young specimens the testis is greenish, and contains nothing but
small pale circular cells; but in adults it assumes a deep orange red-
colour, caused by presence of multitudes of spermatozoa, whose develop-
ment from the circular cells may be readily traced.

‘“‘ This orange-red mass, or rather masses, for there are two in juxta-
position, is described by Mrerrens as the ‘ Samen-behalter’ or vesicula
seminales. He describes them as making their exit, bodily, from the
animal, and then becoming diffused in the surrounding water. This cir-
cumstance, indeed, appears to have furnished his principal reason for
believing these bodies to be what the name indicates.

“The spermatozoa have elongated and pointed heads about 1-500th of
an inch in length, and excessively long and delicate filiform tails.

‘¢ Mertens describes as an ovary, two granulous masses, which he says
lie close to the vesicule seminales, and have two ducts, which unite and
open into this ‘ ovisac.’

“This appears to me to be nothing more than the granulous greenish
mass of cells and undeveloped spermatozoa, which exists in the testis at
the same time as the orange-red mass of fully-developed spermatozoa.

“ T saw nothing of any ducts, nor do I know what the ‘ ovisac’ can be,
unless it be a further development of an organ which I found in two
specimens (fig. 3 ¢), consisting of two oval finely-granulous masses,
about 1-300th of an inch in diameter, attached, one on each side of the
middle line, to the dorsal parietes of the respiratory cavity, and projecting
freely into it.”

“ Still less am I able to give any explanation of the extraordinary en-
velope or ‘ House’ to which, according to MertTEns,* each Appendicularia
is attached in its normal condition. I have seen many hundred specimens
of this animal, and have never observed any trace of this structure; and I
have had them in vessels for some hours, but this organ has never been
developed, although MrErrens assures us that it is frequently re-formed,
after being lost, in half an hour,

“* At the same time it is quite impossible to imagine, that an account
so elaborate and detailed, can be otherwise than fundamentally true,
and therefore, as MERTENS’ paper is not very accessible, I will add his

* I have given this passage at length in order that others may be led to seek its
explanation. Leuckart and Gegenbaur have been as unsuccessful as myself in finding
any such structure; but that it should be purely imaginary seems past belief.

HUXLEY, ON APPENDICULARIA FLABELLUM. 183

account of the matter, trusting that further researches may clear up the
int.

Pe The formation of the envelope or ‘ Haus’ commences by the develop-
ment of a lamina from the ‘ semicylindrical organ’ (ganglion?). This, as
it grows, protrudes through the opening at the apex of the animal (respi-
ratory aperture). Its corners then become bent backwards and inwards,
and thus a sort of horn is formed on each side, the small end of which is
turned towards the apex of the animal, while its mouth looks backwards,
downwards and outwards.

“ At the same time two other horns are developed upwards (the animal
is supposed to have its small end downwards), one on each side. These
are smaller and more convoluted than the others.

‘This four-horned structure consists of a very regular network of
vessels, in which, at the time of the development of the organ, a very
evident circulation is visible; the blood-corpuscles streaming from the
attached end of the organ. ‘ The clearness with which the circulation was
perceptible, together with the great abundance of vessels and the large
extent over which they were spread, were circumstances which led me
(says MerrTeEns) to believe this truly enigmatical structure to be an organ,
whose function was the decarbonization of the blood. The ease with which
the animal becomes separated from this organ is no objection to this view ;
the necessity there seems to exist for the reproduction of the latter rather
confirming my opinion.’

“It is highly desirable that more information should be gained about
this extraordinary respiratory organ, which, if it exist, will not only be
quite swt generis in its class, but in all animated nature. And ina phy-
siological point of view, the development of a vascular network, many
times larger than the animal from which it proceeds, in the course of half
an hour, will be a fact equally unique and startling.”

“ For my own part, I think there can be no doubt that the animal is
one of the Tunicata. The whole organization of the creature, its wide
respiratory sac, its nervous system, its endostyle, all lead to this view.

“In two circumstances, however, it differs widely from Tunicata
hitherto known. The first of them is, that there is only one aperture, the
respiratory, the anus opening on the dorsum; and secondly that there is a
long caudal appendage.

“As to the first difference, it may be observed, that, in the genus
Pelonaia,* an undoubted Ascidian, there are indeed two apertures, but
there is no separation into respiratory and cloacal chambers. Suppose
that in Pelonaia the cloacal aperture ceased to exist, and that the rectum,
instead of bending down to the ventral side of the animal, continued in its
first direction and opened externally, we should have such an arrangement
as exists in Appendicularia.

“With regard to the second difference, I would remark, that itis just the
existence of this caudal appendage which makes this form so exceedingly
interesting.

‘Tt has been long known that all the Ascidians commence their ex-
istence as larvae, swimming freely by the aid of a long caudate appendage ;
and as in all great natural groups some forms are found which typify, in
their adult condition, the larval state of the higher forms of the group, so

* I would particularly remark that the statement that there is no separation
between the branchial and cloacal chambers in Pelonaia is erroneous. At the time
this paper was written I had not examined Pelonaia (whose structure, as I have since
found, differs in no essential point from that of an ordinary Cynthia), and I must have
misunderstood the verbal information given by my lamented friend Professor BH.
Forbes.

Oo 2

184 HUXLEY, ON APPENDICULARIA FLABELLUM.

does Appendicularia typify, in its adult form, the larval state of the
Ascidians.

“« Appendicularia, then, may be considered to be the lowest form of the
Tunicata ; connected, on the one hand, with the Salpe, and on the other
with Pelonaia, it forms another member of the hypothetical group so
remarkably and prophetically indicated by Mr. MacLeay, and serves to
complete the circle of the T’wnicata.

In 1854 Dr. Rudolph Leuckart published, among many
other valuable contributions to zoological science, a memoir
on Appendicularia (for a copy of which I am indebted to the
courtesy of the Author.)*

In several points Dr. Leuckart’s view of Appendicularia
differs from my own.

1. With regard to the “oval finely-granulous masses” at-
tached on each side of the dorsal parietes, Leuckart states
that they are by me considered to be “ probably the ovaries.”
My words, it will be observed, hardly justify this assertion ;
I merely stated that they seem to be a further development of
what Mertens calls the ovisac, which is a very different propo-
sition. Dr. Leuckart’s own view of these bodies, ‘that they
are the earliest indications of the subsequently-formed stig-
mata,” p. 84, is one with which I am, like Gegenbaur, unable
to agree. In fact, as will subsequently appear, Dr. Leuckart
has overlooked the true branchial apertures, unless indeed what
he describes as the anus be one of them. ‘The anal aperture,
he states, is “‘ situated on the right side, near the middle line,
and exhibits a strong ciliary movement.” Now, the anus is
really in the middle line, and the ciliary movement which it
exhibits could hardly be thus characterized, but, as will be
seen below, the description would perfectly apply to one of
the branchial apertures.

2. Dr. Leuckart failed to discover spermatozoa in the organ
which is described by me as a testis. Nevertheless, it will
be shown by-and-by that there can be no doubt that such is
its real nature.

3. Finally, Dr. Leuckart arrives at the conclusion that Ap-
pendicularia is a larval form, and not, as I had suggested, an
adult animal.

In 1855 Dr. Carl Gegenbaur, a very careful and excellent
observer, published a memoir f on Appendicularia, containing
the results of more extensive investigations than had hitherto
been made. Adopting the view that Appendicularia is an
adult form, Dr. Gegenbaur constitutes four species of the

* Zoologische Untersuchungen von Dr. Rudolf Leuckart, Heft. IT.
Salpen und Verwandte.

+ Bemerkungen ueber die organization des Appendicularen, Siebold und
Kolliker’s Zeitsch, B.VI.

HUXLEY, ON APPENDICULARIA FLABELLUM. 185

genus, A. furcata, A. acrocerca, A. cophocerca, and A. caru-
lescens. The most important and novel point in Dr. Gegen-
baur’s paper, however, is the discovery and description of the
true branchial apertures, which had been overlooked by all
previous observers, Dr. Leuckart and myself included. Dr.

Gegenbaur says (I. c., p. 415)—

“* If now we return to the branchial sac, the most remarkable objects are
the two respiratory clefts which lie on its ventral wall and partially em-
brace the entrance into the esophagus. Hitherto, none of those who have
investigated the Appendicularie have recognised the true import of these
organs, although Mertens saw them in Ozkopleura Chamissonis, and
Busch (in Lurycerus pallidus) would, in all probability, have understood
them had he only borne in mind the typical structure of the Ascidians.
Neither Huxley nor Leuckart have mentioned these respiratory aper-
tures.”

After describing the apertures, Gegenbaur proceeds—

“* Exact observation shows that they are not simple apertures in th®
branchial sac like those of the Ascidians, connecting its cavity with th®
surrounding space; but that each is prolonged into a short tube which
converges more or less towards its fellow on the ventral face.”

In A. furcata these two tubes run

** At first parallel with one another downwards (if the animal be sup-
posed to have its anterior part directed upwards, as in the figures), then
form a knee-like curve inwards, running directly towards one another,
and then entirely vanish, so that nothing more could be made out as to
their mode of termination. The function of the respiratory apertures is
therefore, in this case, entirely different from that which they perform in
the Ascidians, in which the water passes through the branchial clefts,
and, after aerating the blood contained in the network of the branchial
vessels, collects in the space between the mantle and the branchial
sac, to be eventually poured out of the cloacal aperture; while in our
Appendicularice the water is led back by tubular prolongations of the
branchial clefts into the body, so as either to become directly mixed with
the blood, or by some further ramifications of the tubes to act through
their thin walls on the surrounding blood. Which of these possibilities
really occurs must remain, for the present, undecided; for although in
A. cophocerca the end of the respiratory tube may be seen very clearly,
yet it is still uncertain whether a bent prolongation of it may not
be continued from this point, and may not, by presenting a transverse
sectional view, give rise to the appearance of an end. I will enter no
further in this place into the discussion of possibilities, my principal
object being the statement of facts. However, I believe I have demon-
strated that there is a tolerably-marked difference between the respiratory
system of the Ascidians and that of the Appendicularic, expressed mor-
phologically by the tube proceeding from the respiratory apertures of the
latter.”

Excessively puzzled to understand how structures so well
marked and so obvious as these should have escaped my
notice, I was, as may be imagined, very desirous to re-examine
Appendicularia ; but although its occurrence in the British

186 HUXLEY, ON APPENDICULARIA FLABELLUM.

Isles was already recorded,* I hardly hoped to find it at acces-
sible distances from the shore. During a few calm days last
autumn, however, the water of the Bristol Channel, near
Tenby, in Caermarthenshire, swarmed with Appendicularie
(in company with annelide and crustacean larve, Sagitta,
echinoderm larvae, Medusa, and Noctiluce), very little dif-
ferent from the southern species which I had previously
described, and I gladly seized the opportunity of repeating
my observations.

The length of the body of different specimens varied very
much; from one-fifth of an inch to a fifth or sixth that size.
The caudal appendage was three or four times as long as the
body, broad, flattened, and rounded at its extremity. The
whole animal was usually colourless, except that the stomach
had a brownish hue. In one instance, however, the caudal
appendage was stained of a bright crimson colour, from what
cause I know not.

With regard to the internal anatomy of the animal, I have,
in the main, to confirm the statements I originally made.
The oral aperture appeared to be more distinctly bilabiate
than I had observed it to be in the southern species, the
upper lip hanging over the aperture, and being, as it were,
enclosed by the concave edge of the lower. The test forms
a thick coat upon all parts of the body, except the posterior
region, over the testis, where it is excessively thin. It often
separates from the outer tunic in a very curious manner, be-
coming thrown into folds and sacculations ; and I was almost
inclined to seek here for Mertens’ “ Haus,” had not his
account been so circumstantially different.

The distance between the walls of the pharynx and the
outer tunic appeared to be considerably greater than in
previously-observed specimens, on the neural side, so that the
blood-sinuses were here very large, becoming still wider near
the ganglion, in consequence of the outer tunic being raised
at this point into a transversely-convex protuberance, gradually
diminishing towards the sides of the body. The pharynx is
richly ciliated, and narrows posteriorly, its wall nearly follow-
ing the contour of the stomach, so that it assumes the shape
of a cornucopia, its tapering hinder portion bending up to
terminate in the right division of the stomach. With regard
to the endostyle, I have nothing important to add to my pre-
vious account, except that I believe it to be here, as in other
Ascidians, the optical expression of the thickened bottom of a
fold or groove of the branchial sac. The large apertures de-

* On the coast of Scotland. See Forbes and Hanley, “ British Mol-
lusea,” vol. iv. p. 247.

HUXLEY, ON APPENDICULARIA FLABELLUM. 187

scribed by Gegenbaur (c), at once strike the eye, not only from
their size, but from the vehement action of the long cilia with
which they are provided, I can in no way account for having
overlooked them, and I see nothing for it but to accept the
fact of the omission as a practical lesson in scientific charity.
The pharynx passes on each side into a funnel-like prolonga-
tion (d, c), with its apex directed towards one side of the rectum.
The dilated base of this prolongation is continuous with the pha-
rynx, its comparatively narrow apex opens externally beside the
rectum. In the mid-length of this conical canal is a thick-
ened circular band (d), formed towards the pharynx of a series
of cellaform bodies, placed in a single series, end to end, and
externally to this of a transversely-banded substance. It is
from this latter portion that the cilia take their origin. They
are arranged in several tiers, are very long, and have a strong
wavy motion,

That we have here a direct communication between the
pharynx and the exterior, and not, as Gegenbaur states, a
communication between the pharynx and certain internal
canals, was made clear to me, not only by direct observation
of the external apertures, but by feeding the animals with
indigo. In two specimens this experiment succeeded per-
fectly ; but it was very curious, that while in the one the
current set im at the mouth and out at the apertures, in the
other the current was in precisely the opposite direction, i
at the apertures and owt at the mouth. The wide stomach is
bent backwards upon itself, so that its two halves or lobes are
pretty nearly parallel, leaving, however, an interval in which
the heart is situated. The right lobe is quadrate in outline,
and undivided, but the left is irregular and lobulated. ‘The
inner surface of the stomach is papillose and ciliated, and
many yellowish granules are scattered through the substance
of its walls. The intestine arises from the upper angle of its
left lobe, bends to the right, and then, when it reaches the
middle line, passes forward to the anal aperture. The rectum
is ciliated, and, as before, I was unable to find any trace of
the tubular “ hepatic’? system, so general among the other
Ascidians.

The heart (0) is large, and occupies a transverse position be-
tween the two lobes of the stomach, laterally, being more
closely in contact with the right lobe, and the testis and base
of the caudal appendage, antero-posteriorly. I was unable to
observe any blood corpuscles, nor could I discover any sign
of that reversal of the direction of the contractions so general
among the other Ascidians. The absence of corpuscles would
have rendered it almost impossible, under ordinary circum-

188 HUXLEY, ON APPENDICULARIA FLABELLUM.

stances, to discover the direction of the circulating currents,
but in one individual, the testis, having attained its full deve-
lopment, had broken up within the body, and the sinuses
were filled with dark masses of spermatozoa. The heart, in
full action, propelled these in a regular course up one side of
the caudal appendage and down on the other (Muller has
already described such a current in his ‘ Vezillaria’), forwards
on the hemal side, and backwards to the heart on the neural
side. This individual was particularly instructive also,
by affording corroborative evidence as to the nature of the
pharyngeal canals. Had these been in any way connected
with the sinus system, as Gegenbaur supposes, the sperma-
tozoa could hardly have failed to pass into them. Nothing of
the sort occurred however; they passed round in the sinus
between the walls of these canals and the outer tunic without
the slightest extravasation, and their dark hue gave the con-
tour of the canals only a better definition than it had before.

The testis was always present; small, discoid, and appa-
rently attached by minute radiating filaments to the parietes
in the younger specimens, it assumed the bilobed form in
the larger ones, occupying a large space behind the alimentary
canal. Individuals with fully-developed spermatozoa were
comparatively rare. In that just referred to, the spermatozoa
had rod-like heads, about 1-7000th of an inch long, with
very long, delicate, and filiform tails; and the testis was re-
duced to a mere transverse band, the greater part of its
substance having apparently been shed in the form of sper-
matozoa. Of a vas deferens I could find no trace.

The rounded bodies (m) on each side of the branchial cavity
anteriorly, appeared sometimes to present an internal clear
cavity, and might then be easily mistaken for ova. But the
absence of any germinal spot, the uniformity in appearance
of their bodies, in all individuals hitherto examined, and
their position, are very great objections in the way of any
such view of the matter.

I must confess that the evidence adduced by Gegenbaur
appears to me insufficient to prove that the bodies which he
describes in other Appendicularie as ovaria are such organs,
and for the present I think it is safest to conclude that the
female organs of Appendicularia are unknown.

With regard to the nervous system and the organs of sense,
the only additional observations of importance refer in the
first place to the caudal nerve, upon which I found at regular
intervals small ganglion-like enlargements (Pl. X., fig. 4), from
which, as well as in their intervals, minute filaments were
given off to the adjacent parts. ‘The largest of these ganglia

HUXLEY, ON APPENDICULARIA FLABELLUM. 189

is the lowest, and when the appendage and the body are
parallel, it is about opposite the end of the rectum. The
nerve here receives a coat of minute rounded corpuscles, so
that an oval mass, about 1-300th of an inch long, is formed,
from whence numerous minute fibrils radiate. The other
ganglia contain not more than two to five such corpuscles.

Gegenbaur states that if Appendicularia furcata be exa-
mined from the dorsal surface, an S-shaped cleft, ciliated at
its edges, will be observed to the right of the ganglion. The
cleft, which occurs only in this species, pierces the wall of
the branchial cavity, and puts it in communication with the
sinus system.

Seeking for this “cleft” in my Appendicularia (flabellum—
cophocerca?), 1 came upon a slightly different, but I have no
doubt, corresponding organ. This is a pyriform sac (q), about
1-800th of an inch in length, presenting at its wider end an
aperture with a produced lip, communicating with the
branchial cavity, and by its narrower extremity abutting
upon the ganglion. The sac was richly ciliated within, and
I have no doubt whatever that it is the homologue of that
“ciliated sac,” whose existence under different forms appears
to be universal among the Ascidians. There is every reason,
however, to regard this as an organ of sense, and it never
communicates with the sinus-system, so that probably
Gegenbaur’s statement may be regarded as an error of inter-
pretation.

I could discover no transverse muscles in the caudal
appendage, but only an upper and a lower layer of longi-
tudinal fibres, between which the axis of the tail was enclosed.
Whether this central axis is a solid body, or a membranous
capsule filled with fluid, I cannot say, but it is assuredly
closed at both ends. Its closed and rounded proximal ex-
tremity is readily seen, and I feel confident that there is no
such communication between the heart and the interior of the
axis as Gegenbaur supposes. In the individual already
referred to, in which the spermatozoa were effused into the
general current of the blood, none entered the axis of the
caudal appendage.

The discovery of the external openings of the pharyngeal
canal and of the true nature of the supposed “ciliated
cleft,” appears to me to possess peculiar interest, in that it
eliminates those structural peculiarities hitherto supposed to
exist in Appendicularia, which were in discordance with the
general plan of the Ascidians. That an Ascidian should
have apertures in its pharynx, establishing a communication
between its cavity and the sinus system, would be a great

190 HUXLEY, ON APPENDICULARIA FLABELLUM.

anomaly ; but that Appendicularia, being an Ascidian, should
possess a ciliated sac, and that the wall of its pharynx
should possess ciliated apertures or stigmata, establishing a
communication between its cavity and the exterior, inde-
pendent of the mouth, is only a strengthening of the evidence
of its truly Ascidian nature.

Again, while the existence of these apertures establishes
further most interesting relations of representation between
Appendicularia and the larve of Ascidians, especially of
Phallusia, it cuts away all ground for any supposed relations
of affinity between the two. In Phallusia, it is true, as
Krohn has shown, the cloaca is at first double, and each half,
which might be regarded as the equivalent of the outer half
of the pharyngeal canal in Appendiecularia, opens by an inde-
pendent aperture ; but then the anus, instead of opening
externally, terminates in one of these cavities. The enor-
mous size, coarse ciliation, and very small number of the
pharyngeal stigmata in Appendiculuria, too, are wholly unlike
anything larval.

The development of the nervous system and of the organs
of sense is quite opposed to the supposition that Appendicu-
laria is a larval form; and, in answer to Leuckart’s suggestion
that developed spermatozoa and ova are found in insect
larvee, I would urge that, in these matters, it is hardly safe to
judge of one class by analogical arguments drawn from
another. [ am not aware that such early development of the
reproductive products has ever been observed in any
mollusk.

The discovery of the true branchial apertures in Appen-
dicularia appears to me to bear no less importantly upon the
moot question of the homologis of the Tunicata and Polyzoa,
by removing all doubt as to the truly pharyngeal nature of
the branchial sac in the Ascidians. But, if it be a pharynx,
it cannot be the homologue of the conjoined tentacles of the
Polyzoa, which are entirely pre-pharyngeal structures.

Whatever may be the result of future inquiries as to the
arrangement of the female organs in Appendicularia, 1 ecan-
not doubt that in A. flabellum we have an adult form im a
male state. Whether the female has a totally distinct form,
or whether the ova are developed in the same form at a
subsequent period (I have observed individuals so young that
it is hardly conceivable that the ova should be developed at
an earlier period), is a problem of very great interest, but for
whose solution I see no materials at present. Considering
the abundance in which Appendicularia occurs on our own
shores, the collection of the requisite data ought to present no

HUXLEY, ON THE CHEILOSTOME POLYZOA. 191

great difficulties to those who possess leisure and the oppor-
tunities of a sea-side residence; and to any such person,
whose eye may fall upon these pages, I commend the investi-
gation as one which will amply reward him.

Note on the RerropuctirveE Oreans of the CuEILosToME
Potyzoa. By T. H. Huxtey, F.RS.

Osvious as are the ovicells and partially-developed ova of
the chetlostome Polyzoa, the precise position of their ovaria
and testis has not yet been determined ; the general idea that
the ova are developed within the ovicells being wholly an
assumption. ‘The investigation of the question is not without
difficulty, on account of the delicacy of the ova in their young
condition, the greater or less opacity of the ectocyst, and the
obstruction offered by the other viscera if the cells be viewed
in any of the positions which they ordinarily assume, lying,
that is, on their front or back faces. By tearing up a
polyzoarium, with needles, into single series of “Bie and
causing one of these series to lie upon its side, I found the
process of examination much facilitated.

In the younger cells of Bugula avicularis, I find that, as in
many of the hippocrepian Polyzoa, there is a cord, or
funiculus, connecting the extremity of the stomach with the
bottom of the cell, and attached to this I found, close to the
stomach, a single small pale ovum, commonly possessing a
double eerminal spot. At its lower attachment, on the other
hand, the funiculus is surrounded by amass of minute, pale,
spherical corpuscles. In these cells, no ovicells were as yet
developed; but in older cells they make their appearance as
diverticula of the ectocyst and endocyst, having their internal
cavity continuous by a narrow neck with that of the cell.
A valvular aperture eventually becomes developed at the
lower part of their anterior face.

In such older cells, the ovicell is at first empty, and we find
the ovum attached to the funiculus increasing in size, and
acquiring a reddish coloration; but in those still further
advanced, a similar, but larger ae redder, body makes its
appearance in the ovicell, and after undergoing yelk-division
becomes a ciliated embryo, In these older cells, again, we
find the granular mass at the bottom of the cell gradually
developing into a mass of spermatozoa, which eventually
float loose in the cavity of the cell.

I have no doubt, therefore, that in Bugula avicularis the
ovarium is situated at the top of the funiculus, the testis at

192 CURREY, ON REPRODUCTIVE ORGANS OF FUNGI.

its base; that impregnation takes place in the cavity of the
cell, and that the ovum passes from thence into the ovicell—
there, as in a marsupial pouch, to undergo its further deve-
lopment. The testis has a similar form and structure, and
its position is invariably at the bottom of the cell in Bugula
flabellata, B. plumosa, and Scrupocellaria scruposa, but that
of the ovarium varies greatly. Thus in B. flabellata the
ovarium is placed at the middle of the back of the cell, and
is not directly connected with the funiculus; in B. plumosa,
it lies at the apex of the back of the cell; in Serupocellaria
scruposa, it is at the upper and back part of the cell. The
ovarium rarely presents more than one or two ova.

On the Reerovuctive Oreans of certain Funet, with some re-
marks on Germination. No. II. By Frepericx Currey,
Esq., M.A.

Tue following paper is intended as a sequel to a previous
communication on the same subject which appeared in the
last volume of this Journal (see vol. iii., p. 263.) The instances
in which a particular fungus has been observed to produce a
variety of fruits differing essentially from one another, are
already very numerous, and are daily on the increase. This
polymorphism of fructification is highly interesting and im-
portant, not only in a physiological point of view, but from
the effect which it must necessarily have upon the classifica-
tion of the vast tribe of Fungi. Not only have different
genera of the same order been already proved to be identical,
but Fungi originally classed in different orders, and appa-
rently of widely-different habits and structures, have been
proved to be the produce of the same mycelium. The facts
which I proceed to mention, are principally the result of
observations made since the publication of my former paper,
and they will, I hope, be considered interesting additions to
this branch of microscopical science.

1. Asrerosporrum Horrmanni—Aunze.—The fungus known
by the name of Asterosporium Hoffmanni is a plant which is
frequently met with in this country upon twigs of beech. It
was originally ranged under Séi/bospora, but was separated by
Kunze as long ago as the year 1819, and erected into a
separate genus. Although the very peculiar shape of its
spores affords some grounds for this separation, the plant
accords in every other respect with Sti/bospora, in which genus
it is still retained by some mycologists. Each one of the

CURREY, ON REPRODUCTIVE ORGANS OF FUNGI. 193

spores of this singular plant consists of four bi, tri, or quadri-
septate pointed cones radiating from a common centre, but the
axes of which do not lie in the same plane. I have called
the rays cones, but this is not strictly correct, inasmuch as
they are generally slightly curved like a cow’s horn. The
spores have been compared to the instrument called crow’s-
Jeet, which, when thrown on the ground, always present one
point upwards, as would manifestly be the case with these
spores. In fig. 1, Pl. XI., I have represented a spore as seen
under a magnifying power of 500 diameters. I would ob-
serve, that although the normal number of rays is four, I have
met with spores in which two of the rays have failed, thereby
producing the appearance shown in fig. 2, which represents
one of these abnormal spores magnified 350 diameters. Spores
of this latter kind were tolerably numerous in one or two of
the specimens which I lately examined, and upon which the
observations to which this paper relates were made. The
threads of the mycelium are of a brownish colour, sometimes
septate, and not unfrequently branched. In the specimens
just mentioned these threads were so closely packed as to
present somewhat the appearance of a membrane composed
of elongated cells, but nevertheless, upon close inspection, it
might be seen that the threads were not actually adherent
to one another. The spores of Asterosporium, like those
of the Stilbospore in general, eventually produce a fissure in
the bark under which they grow, and are ejected from beneath
the epidermis; if the atmosphere be moist they have the
appearance of tubercles of black jelly covering the twigs
upon which the plant grows, but which tubercles, in hot
weather, cease to be gelatinous, and become hard and dry,

I must now direct attention to a plant which has hitherto
been considered quite distinct from Asterosporium, and which
bears the somewhat uneuphonious, but withal expressive,
name of Myriocephalum botryosporum. This fungus, which
has all the characters of a Stilbospora, was placed by M. Mon-
tagne in that genus, but has borne a variety of names. It is
the Cheirospora of Fries, the Rhabdosporium of Chevallier, the
Hyperomyxa of Corda, the Botryosporium of Schweinitz, and
the Myriocephalum of De Notaris, and Fresenius. It may be
recognized under the microscope at a glance, by the peculiar
grape-like bunches of green spores borne on the apices of long
slender filaments, which are sometimes, though not generally,
branched. Fig. 3 represents the upper part of one of these
filaments terminating in a bunch of spores ; and fig. 4 repre-
sents a similar bunch of spores, in which, as I have observed
to be the case in many instances, the terminal spore, and

194 CURREY, ON REPRODUCTIVE ORGANS OF FUNGI.

sometimes the two upper spores, considerably exceed in dia-
meter those spores which are lower in the chain, Fig. 3 is
magnified 500, and fig. 4, 550 diameters.

In the first week of January inthe present year, several dead
branches of a beech-tree, ina wood near the Weybridge Station
of the South-Western Railway, were covered with spots, each
consisting of a small circular black stain, with a central papilla.
A few days later, a large quantity of rain having fallen in the
interval, and the atmosphere having been unusually moist,
the spots had increased considerably in size, and assumed a
pulvinate or hemispherical shape. A vertical section of one
of these pulvinuli, carried down through the bark, presented
the appearance shown by fig. 5. ‘The epidermis was lifted up,
and a conical cavity formed between that and the inner bark,
This conical cavity was completely filled with the brown-
coloured mycelium above-mentioned, the threads of which
lay excessively close to one another. This mycelium was
covered with the ordinary spores of Asterosporitum Hoffmanni,
similar to the one shown in fig. 1]. In one or two of the
plants many of the spores of the Asterosporium had assumed
the form shown in fig. 2, and in other instances, multicellular
spores without horns existed in considerable quantities, always
towards the lowest portion of the conical cavity. The gelati-
nous tubercle which crowned the cavity, and the section of
which is seen in fig. 5 above the laciniz of the epidermis,
consisted of elongated white threads enveloped in a mucous
medium, each thread bearing at its apex bunches of spores
such as those shown in figs. 3 and 4. A careful examination
of a number of specimens quite satisfied me that the white
threads were prolongations of the brown mycelium, the threads
of the latter becoming gradually narrower and paler in colour
in approaching towards their summit. In short, the pale
brown filaments which filled the cavity beneath the epidermis,
and which bore the spores of the Asterosporium, and the
elongated whiter filaments, which traversed the mucous sub-
stance of the gelatinous tubercle, constitute but one of the
same mycelium, a fact which necessarily leads to the inte-
resting conclusion that Asterosporium Hoffmanni and Myrioce-
phalum botryosporum are only varieties of fruit of the same
fungus.

The forms above mentioned, however, are not the only
produce of this fertile mycelium. The moist atmosphere
which converted the dry papillate black spots into gelatinous
tubercles, had the effect of producing a further fructification
in the form of white colourless elliptical bodies, conidia in
fact, which were produced in abundance on the upper por-

CURREY, ON REPRODUCTIVE ORGANS OF FUNGI, 195

tions of the threads of the mycelium. In some specimens
the grape-like bunches of spores were literally floating in a
sea of these conidia, which were so numerous that I can only
compare them to the mass of similar bodies which may be
seen under the microscope at any time by moistening a spe-
cimen of Tubercularia vulgaris, ‘These conidia spring laterally
from the threads upon which they grow, and are, I think, pro-
duced in moniliform rows. They can seldom, however, be
observed tz situ, on account of the rapidity with which they
are shed when the plant is moistened. Fig. 6 represents
several of these conidia magnified 500 diameters,

In the Uredines, where the dimorphism, or rather poly-
morphism, of the fruit has been so clearly established, the
constant occurrence in the same matrix of the different sorts
of spores was observed long before it was proved that these
varieties were the produce of the same mycelium. Now
Asterosporium Hoffmanni is, as I have mentioned, a common
plant, and Myriocephalum botryosporum, although it is not
nearly so well known, and has not, as far as 1 am aware, ever
been found in this country before, has, nevertheless, been
noticed by several continental mycologists, none of whom,
however, have suggested the identity of the two, or have even
mentioned their association in growth. Fries, in the ‘Summa
Vegetabilium Scandinavie,’ has noticed the close connexion
existing between Hyperomyxa, Myriocephalum, Asterosporium,
and the Sti/bospore in general. He says, speaking of the two
former, ‘‘ Mediante Asterosporio cum veris Stilbosporis mani-
feste seriem contiguam sistunt: omnibus eadem genesis
vegetatio, stroma mucoso-floccosum, e.s. p.” Even Fries,
however, has not suggested the identity which I hope to have
established.

These remarks must not be considered as being made at
all with the view of magnifying the importance of the dis-
covery, but solely for the purpose of calling attention to
the fact, that since so many distinguished mycologists have
had both plants under their observation, and have not noticed
their association, it is probable that the occurrence of the two
kinds of fruit contemporaneously is a circumstance of rare
occurrence. We know little, if anything, of the atmospheric
conditions necessary for the favourable growth of particular
Fungi; the mycelium of Agaricus strobiliformis has been
known to lie dormant for 14 years, and yet the Agaric, the
fruit of that mycelium, has appeared after that lapse of time
true to its former locality. May not the coexistence of the
two fruits of the Asterosporium be dependent upon peculiar
atmospheric conditions, and be of as unfrequent occurrence ?

196 CURREY, ON REPRODUCTIVE ORGANS OF FUNGI.

I have spoken of Corda’s genus Hyperomyza as being iden-
tical with Myriocephalum. The only distinction is, that Corda
represents each thread and each fascicle of spores as enveloped
in a separate mucous sheath. There can be no doubt, I
think, that these mucous sheaths form, by their dissolution,
the gelatinous mass in which all the flocci and capitula of
spores are enveloped. In the ‘Summa Vegetabilium Scandi-
navie, the genus Hyperomyza immediately precedes Myrioce-
phalum, and upon the former Fries makes the remark, ‘* Forte
non satis diversum a sequente ; in quo vagina (1. ascus) jam
primitus resorbtus ut spore nude sint.” ‘ Nude” here must
mean naked, so far as regards any special protective organ, for
of the existence of the general mucous envelope there can be
no doubt.

The dampness of the atmosphere at the period of the above
observations was of course favourable to germination, and |
observed many germ-filaments amongst the mass of the
Myriocephalum spores. A remarkable feature in these germ-
filaments was their great diameter as compared with that of
the individual joints of the torulose capitula. This is so
striking as almost to induce the belief that each capitulum
germinates as a whole. In fig. 7, 1 have drawn one of these
germ-filaments under a power of 350 diameters, and an in-
spection of that figure will show its great width. The
filament is divided by a multitude of transverse septa, and
the contents of each cell are granular with two or three
nuclei. The colour of this particular one was a deep sea-
green, much darker than is usually the case with the germ-
filaments of Fungi, but others occurred which were almost
colourless.

In the ‘ Botanische Zeitung’ for the 25th of February, 1853,
Dr. Riess describes a new species of Prosthemium, which he
calls Prosthemium stellare, and which bears a tuft of spores
analogous to Myriocephalum. He suggests that the entire
fascicle may, perhaps, be considered to be a single highly-de-
veloped spore. If the same supposition could be made in the
case of the Myriocephalum, it would at once explain the appa-
rently unprecedented size of the germ-filament; but whether
or not such a supposition be admissible I am not prepared
to give an opinion,

It remains to say a few words with respect to the name by
which the plant here discussed should henceforth be distin-
guished. I think there can be no doubt that it should be
retained in the genus Sée/bospora. Although it has become
common lately to speak of the Stz/bospor@ as only stylosporous
states of Spheria, it is obvious that the genus cannot be

CURREY, ON REPRODUCTIVE ORGANS OF FUNGI. 197

extinguished until more has been effected than has yet been
done towards tracing the different species to their perfect
ascigerous condition. Inasmuch as Asterosporium and Myrio-
cephalum have both been placed, the one by Montagne and
the other by Persoon, in the genus Stilbospora, the best
course, now that they prove to be the same, will be to retain
them in that genus with an appropriate specific name. For
the latter I should propose the term “ mzlitaris,’’ since both
kinds of fruit resemble instruments of warfare—the stellate
spores being similar to crowsfeet, and the fasciculate spores
being something like grape-shot. In case any of my readers
may not be familiar with the former instruments, I may state
that crowsfeet consist of a spherical piece of iron with four
spikes concentric with the sphere, and radiating from it in
different planes. They were formerly used by throwing
them in numbers on the ground, with the view of laming the
enemy’s horses.

STEGANOSPORIUM CELLULOSUM.—This plant has not yet
been recorded amongst the British Fungi, although I can
hardly believe that it has not been observed. The genus was
separated by Corda from Stilbospora on the ground of the
more compound nature of the spore. He distinguishes two
species, Steganosporium pyriforme and S. cellulosum; there
does not, however, seem to be any substantial difference
between the two, for the existence or non-existence of longi-
tudinal septa in the spores is clearly unimportant, inasmuch
as spores are to be found in the same specimens some with
and some without such septa. The difference in the nature
of the perithecium is also, I think, insufficient to justify the
separation of the two species, even if such difference be not
(as I suspect it is) dependent merely upon accidental circum-
stances of growth. It would probably, therefore, have been
better to follow Fries, and to have united the two species
under the common name of Stilbospora cellulosa ; ut the follow-
ing observations will, I venture to think, be considered suffi-
cient to show that Steganosporium cellulosum and S. pyriforme
are only forms of fruit of a Spheria allied to, if not identical
with, S. amblyospora.

In July, 1855, I found a dead branch of a Sycamore in my
garden at Blackheath covered with Steganosporium cellulosum.
With the view of ascertaining whether any other fungus lay
dormant in its vicinity, I placed some pieces of the branch in
a green glass bottle with some damp moss, corked the bottle
tight, and exposed it to the full mid-day sun. In a few days
the ostiola of a Spheria appeared on one of the pieces of

VOL. IV. P

198 CURREY, ON REPRODUCTIVE ORGANS OF FUNGI.

stick, and upon examining the Spheria I found the asci
(figs. 8 and 9) mixed with the Steganosporium spores (figs. 10
—15) in the same perithecia. This would seem to show
satisfactorily that the Steganosporium and the Spheria are
identical, a conclusion which was fortified by a further ex-
amination of the specimens of the former Fungus. Careful
sections of these latter plants disclosed the existence of the
bodies represented in figs. 16, 17, 18, and 19. These bodies
were seen in situ attached to the stratum proliferum (it can
hardly be called perithecium) of the Steganosporium. Figs. 16
and 17 can be nothing else than empty asci; they have pre-
cisely the shape of these latter organs, and exhibit very
distinctly the internal second membrane common to the asci
of Fungi in general.* Figs 18 and 19 are also, I think,
manifestly imperfect asci. In fig. 19 the internal membrane
is clearly visible at the lower extremity, and in each of them
the endochrome is divided into eight distinct, somewhat
irregularly-shaped fragments, which may fairly be assumed
to be incipient or abnormal sporidia. These bodies (figs. 16
to 19) were, as I have mentioned, attached to the stratum
proliferum, and were situated at the bottom of the lenticular
cavity from which the cirrhus of the Steganosporium spores
emerged ; the ejected mass or cirrhus consisted almost entirely,
_ if not exclusively, of these spores, which are shown in figs. 10
to 15; and the same spores also filled the middle of the
cavity, whilst the lower portion of it was covered exclusively
with the organisms drawn in figs. 16 to 19.

With regard to the Spheria, the aseci and sporidia drawn
in figs. 8 and 9 will enable the reader to form an opinion as
to the species. I have little doubt that it is Spheria ambly-
ospora, a species which I have found on another occasion
associated with Steganosporium cellulosum. The sporidia,
however, are much more obtuse than is usual with S.
amblyospora, in which the successive cells generally decrease
rapidly in size from one end to the other, rendering the
sporidium truly lageniform. The bottom sporidium in the
ascus, fig. 9, is nearly the normal form in Spheria ambly-
ospora. In this latter ascus, where the sporidia are not quite
ripe, the gelatinous envelopes seen in fig. 8 were not visible,
and the sporidia were of a much paler colour than in fig. 8.

* In figs. 32, 33, I have drawn two asci of Spheeria herbarwm, which
I have observed to dehisce in a singular manner. In fig. 32 the top of
the ascus appears to have been carried upwards, and the internal second
membrane is visible at both ends. In fig. 833 the ascus has opened as it
were with a hinge ; the second membrane is reduced to a thread, which is
attached to and encloses a single sporidium,

CURREY, ON REPRODUCTIVE ORGANS OF FUNGI. 199

Fig. 20 represents a ripe sporidium from the same peri-
thecium as the ascus fig. 8. Fig. 21 is a sporidium from
another specimen of Spheria amblyospora. This sporidium, it
will be seen, has its envelope fully developed, and its colour,
like that of all those which were quite ripe, was a dark olive-
brown. Most of the sporidia in all the specimens had three
septa, but some had two, and a few only one.

By placing the spores of the Steganosporium in water under
thin glass, and securing them from evaporation, I found that
they germinated without difficulty, and the forms assumed by
them at the commencement of that process were very curious.
Several of the partitions into which the spores were divided
threw out contemporaneously slender white filaments, the
colour of which contrasted strongly with the dark green of the
spores. At this stage of the process the spores (Figs. 22,
23, 24) with their shoots had the appearance of large insects,
the spores representing the bodies, and the germ-filaments
the legs. One of these germinating spores had a round
vesicle attached to the extremity of one of the germ-fila-
ments, but whether this vesicle was really the expanded
apex of the filament or the spore of some other Fungus
accidentally adherent, I cannot say with certainty. The latter
is not improbable, for every Mycologist must be aware that
notwithstanding the greatest care in cleaning, the spores of
some previously-examined Fungus will frequently adhere to
the slides, and if care be not taken to distinguish such inter-
lopers, erroneous conclusions may be the result. Fig. 25
represents a spore in which the germ-filament has attained a
considerable length, and has thrown out lateral branches in
many directions. A few days later fresh branches had been
produced from the main filament, and further lateral shoots
from these fresh branches, the whole forming such a com-
plicated maze of filaments that any attempt to draw them
with the Camera lucida would have been quite hopeless.
The filaments were of a somewhat greenish colour with
granular contents, and a multitude of small nuclei were
scattered here and there irregularly throughout their whole
extent.

It will be seen by comparing figs. 10—15 and figs. 22—25,
that the Steganosporium spores vary much in size and shape.
The colour is constant, being a dull olive-green.

Spnz#rta Cryprosrorit.—In the former paper to which I
have referred, I described a new species of Spherta under the
above name, and at the same time certain facts were brought
forward, which appeared to show that the Fungus known by

P 2

200 CURREY, ON REPRODUCTIVE ORGANS OF FUNGI.

the name of Cryptosporium vulgare is only an imperfect state
of this particular Spheria. During the last autumn I met
with the same Spheria in two places, in the neighbourhood
of Chislehurst, in Kent ; and the further examination which I
had then an opportunity of making, not only confirmed the
previous supposition of the identity of the Spheria and the
Cryptosporium, but also disclosed the existence of some
curious transformations of the fruit of the former, which are
worthy of notice. The normal form of the fruit of Spheria
Cryptosporti is shown in fig, 26, and figs. 27 to 31 represent
the varieties of fruit just mentioned. The bodies shown in
figs. 27 and 28 resemble the common spores of Cryptosportum
vulgare, although their length is more considerable, and they
have an undulating form, which is not usual in these spores.
In fig. 28 two are seen, which have become twisted round
one another. It appears to me that these bodies may be
elongated asci, in which the endochrome instead of forming
sporidia has remained dispersed throughout the interior in a
granular condition. A reference to my former paper, and to
the figures accompanying it, Plate XII. in Vol. ii1., will show
the manner in which, according to my view, the formation of
sporidia froin the endochrome takes place. In fig. 29 the
lower end of the ascus has become transformed into a globular
vesicle, in which a considerable quantity of the endochrome
from the upper end has become accumulated. No symptom
of the formation of sporidia is visible either in this or in
the two other abnormal asci represented in figs. 30 and
31. In the one shown in fig. 30, the ascus has apparently
become swollen at the wpper extremity ; and in fig. 31 the two
ends are elongated, and a globular vesicle has been formed
between them.

I have observed transformations very similar to the above
to take place in the fruit of Spheria verruceformis; but the
figures and description of these would occupy so much space
that I must postpone them for a future communication. I
think it not unlikely that these monstrosities of fructification
are the result of excess of moisture; but this is a matter
requiring further investigation.

ON SIMILARITY OF FORM IN SNOW CRYSTALS. 201

On the Stmivarity of Form observed in SNow Crystats as
compared with those of Campuor under certain conditions of
CrystatiizaTion. By Josrepu Spencer, Esq. (Read before
the Greenwich Natural History Club, Jan, 2, 1856.)

INVEsTIGATIONS tending to throw some light on the laws
which determine the external forms and internal structure
of crystallized bodies, may not be considered devoid of in-
terest. The field of research is so extensive, the forms of
crystals so varied and beautiful, and a knowledge of their
primitive and resulting forms of such importance to the
kindred science of chemistry, that any additional facts on the
subject may be considered desirable. Much attention has
been given of late to the peculiar forms assumed by snow, or
to speak more correctly, by water under certain conditions of
crystallization. ‘The subject was first introduced, I believe,
by a distinguished member of this Society, and has since been
most ably worked out by him, Every one must have been struck
with the beauty and variety of snow-crystals, and some very
truthful delineations of them have been published. A great
difficulty sometimes has been felt by those desirous of studying
them from their very perishable nature, as they require to be
maintained at a temperature below the melting point of ice,
or 32 degrees of Fahrenheit’s thermometer. The usual plan
of viewing them has been by the microscope in the open air,
or ata window. MHaving tried both plans, and found them
beyond my powers of endurance for any length of time, I
have been driven to devise a plan for viewing them within
doors, and in comparatively warm rooms. This plan I shall
be happy to explain, at the conclusion of this paper, to any
members of this Society who may be interested in the sub-
ject. Very considerable interest attaches to the forms
assumed by snow, from the intimate connexion that appears
to exist between the production of certain forms of crystal-
lization, and certain states of the atmosphere. Meteorology
has of late years obtained that attention which its importance
deserves, as only by a slow and laborious collection of facts,
extending over a series of years, can we hope to arrive at a
knowledge of the laws which control the mighty agencies at
work in the atmosphere of our earth, and the study of which
is of such importance to the health and well-being of man.
It would be very desirable, however, in the study of snow-
crystals, to find some substance similar in its habits of
crystallization but of a less perishable nature, and which
would enable us to trace the progress of the crystals from the
simplest up to the most complicated forms; so that reasoning

202 ON SIMILARITY OF FORM IN SNOW CRYSTALS.

by analogy we might be able to throw some light on the
subject.

The well-known substance, camphor, I find, fulfils all these
conditions, and possesses some peculiar properties that make
it an interesting subject of study. Some of these peculiarities
have been long known; and I believe that the old-fashioned
instrument or philosophical toy, called the weather-glass, was
a tube hermetically sealed, and containing a solution of
camphor. Campbor, crystallized slowly, does not usually
assume the form of hexagonal crystals, but like snow or ice
takes the arborescent form, very similar to the fronds of
Ferns: this may often be observed in the case of ice in the
beautiful forms assumed on the surface of windows in winter.
Camphor usually takes the same form under like conditions,
but requires a rapid crystallization to produce hexagonal
crystals. The most convenient way to repeat these experi-
ments on camphor is to make a solution of this substance in
alcohol or spirits of wine, and add thereto some water of
ammonia—the precise quantities are not of much moment,
provided there be an excess of camphor undissolved. I
usually add a small quantity of water to the clear solution
drop by drop, till the precipitated camphor ceases to be re-
dissolved. The simplest form assumed by crystallized
camphor is a flattened disc: very frequently two discs are
united together by a smaller one in the centre, giving rise as
the process of crystallization goes on to twin crystals, super-
posed one on the other precisely like snow crystals. These
discs frequently possess what appears to be a nucleus, which
is coloured more or less; the disc and nucleus differing
in colour, the colours being most frequently complementary
to one another. I had proposed to myself to mount some of
these hexagonal crystals of camphor to exhibit to the Society,
but have found a difficulty in obtaining a suitable medium
which would not possess a solvent action upon them: they
are so readily procured, however, by a rapid evaporation of
the solution of camphor under the microscope, that this will
hardly be an objection. It must not be expected that we
should meet with that infinite variety of form observed in
snow crystals in the case of hexagonal crystals of camphor,
since we can only produce them on a very small scale, com-
pared with the millions we can select from in the case of
snow. My object, therefore, has been, in introducing the
subject to the notice of the members of this Society, to draw
their attention to it as an interesting subject for experiment
during leisure moments in the course of the winter, when
most probably they will have an opportunity of comparing

ON SIMILARITY OF FORM IN SNOW CRYSTALS. 203

for themselves the crystals of snow and of camphor, and of
throwing still further light on the subject.

Further Observations on the Stm1varity of Forms observed
between Snow Crystats and those of Campuor. By JAmMEs
GuaisHER, Esq., F.R.S. (Read before the Greenwich
Natural History Club, Feb. 6, 1856.) Plate XII.

Tue field of inquiry thus opened by Mr. Spencer has since
engaged a portion of my attention. The following are some
of the results of observation carried on at intervals, the solu-
tion being provided by Mr. Spencer, and a part, I believe, of
that employed by him in his own experiments. The follow-
ing are my notes on the subject.

The process of crystallization, according to my own obsery-
ation, appears to proceed rapidly, and to commence simul-
taneously with the action of the air upon the liquid; but to be
by no means certain of proceeding similarly under apparently
similar conditions.

The process of crystallization, in this case, bearing the closest
analogy to that of snow, and the one of most frequent occur-
rence, presents an endless succession of minute, round, moving
dots, passing to and fro with the restless movement of animal-
cules ; every instant these globules very perceptibly increase in
size, and soon develop points, generally six in number, which
continue to enlarge until they assume the character of
arborescent pinnae, the additions to the elementary figure
being effected at an angle of 60°. The crystal, when arrived
at perfection, immediately begins to simplify, and continues
to do so until quite evaporated. If, however, the room be
cool, and the evaporation proceed slowly, as is best in these
experiments, it is not unusual to perceive one or two of the
radial arms elongating themselves at the expense of the rest,
and the greater number subsiding into a kind of crystalline
film or disc, of which I will speak presently.

These figures never appear to attain to any great degree of
complexity, or to be other than arborescent when in their final
and most perfect stage of development. In some of the
richer specimens may be seen, around the nucleus, a somewhat
thick aggregation of little drops or knobs; but these are not
arranged with the geometrical precision to be observed in the
crystals of snow, and speedily disperse into the crystalline
matter of the arms, to which they contribute a still more
arborescent character. The downward and tertiary spike,
common to the snow crystal, is here often met with, and forms
a point of analogy worthy of remark.

204 ON SIMILARITY OF FORM IN SNOW CRYSTALS.

One main difference between these and the figures of snow,
is that they exhibit an entire want of angularity, and only
approximate, even when at their greatest perfection, to the
snow crystal just as it appears before finally dissolving.
Moreover, they have at all times a watery, uncertain, fluctuat-
ing outline and appearance generally, as though viewed
through a watery medium; even the disc into which they
generally subside, presents the same indefinite wavy outline, and
the transparency of the parts is rather that of globules of water
than of crystals.

These peculiarities attach to them at all times; but the
appearance of the field differs very considerably, under, to
all appearance, similar circumstances of observation. Some-
times it is covered with minute globular bodies (crystals in
embryo), which quickly settle close to each other in clusters,
and never go beyond the figure of a well-defined star. Some-
times they may be seen in fewer numbers, swiftly travelling
over the field ; some single, but the greater number double,
for they share in this respect a peculiarity of the snow
crystals, but differ in their being united by a point of contact
common to the two, instead of being united by a slender axis
as in the crystal of snow. As they roll over, their conforma-
tion is distinctly visible ; and it is curious to watch the double
process of development as the star emerges from the ele-
mentary globule, which is every instant perfecting itself to the
complete figure, when it settles down and remains stationary
till the moment of its final departure. Sometimes they unite
in rows, sometimes in clusters so intermixed that the in-
dividual forms are not distinguishable.

The greater number of these figures, indeed I may say it
is the rule with them, crystallize at an angle of 60°; there
are, however, exceptions, and on one occasion | failed to
discover any other than eight-rayed crystals, arborescent and
differing only in regard to the additional radii. They have
all of them, with few exceptions, a nucleus generally circular
but sometimes star-like, with parallel and inner markings,

I have made mention of a flattened disc into which
these bodies disperse. ‘This disc is in itself a most interest-
ing study; it is curiously intersected in different directions
by sinuous channels of different densities. It forms quickly ;
and when the room has been overheated I have seen the field
covered with discs with instantaneous rapidity, without ex-
hibiting a trace of stellar crystals. Sometimes the disc forms
round one-half of the crystal, dissolving the parts in contact
with itself.

This is all that I have been able to collect respecting these

ON AN EASY METHOD OF VIEWING DIATOMACE®. 205

bodies, which chiefly resemble the crystals of snow in their
hexagonal, stellate, arborescent shape and in the form of their
pinne. If not, however, intimately allied, it is interesting
to observe and compare the manner of their change ; and a
continuation of these observations, varied by experiment
and the employment of other solutions, may yet afford
information on a subject which, as Mr. Spencer remarks, is
of peculiar interest, as uniting the confines of meteorology
and chemistry.*

On an Easy Meruop of viewing certain of the Diatomace.
By Joun Cuartes Hatt, M.D., Physician to the Sheffield
Public Dispensary, &c. &c.

WE shall most certainly add not a little to the chances of
increasing our knowledge of the intimate structure of the
infusorial tribes, if any means can be suggested by which the
number of observers may be increased. Possessed of a good
microscope by one of our principal makers, a student may
imagine that he is in a condition at once to ascertain the
exact form and nature of certain shells of Bacillaria, certainly
amongst the most difficult of test objects; a very few trials
will, however, convince him that even the best-constructed
eighth will not fully display their peculiar markings without
some accessory instrument. For this purpose the achromatic
condenser of Mr. Gillet, as made by Mr. Ross, or the achro-
matic condenser of Powell and Lealand, or of Smith and
Beck, is usually employed. The purse, unfortunately, of the
most enthusiastic labourers is not always the heaviest; a mi-
croscope is bought and added to from time to time, and the
condenser, so much coveted, must often be waited for some
years.

We propose in the present paper to show how, for a few
shillings, this apparatus may, for a time at least, be dispensed
with; and how the Pleurosigma Hippocampus, Pleurosigma
formosum, Pleurosigma angulatum, and other individuals of
this genus, may be shown in the most satisfactory manner ;

* An infinite variety of crystalline forms, apparently allied to those
of snow and of camphor, is presented, when a drop of a weak solution
of common salt, to which a small quantity of wrea has been added, is
dried at a moderate temperature on a slip of glass held over a spirit-lamp.
The change produced by urea in the shape of the crystals of common salt,
from the octahedron to the dodecahedron, or some derivative, has been
long well known; and the fact may be usefully employed, with certain
precautions, to determine, under the microscope, the presence of extremely
minute quantities of wrea in animal and other fluids.—{ Eds. ]

206 DR. HALL, ON AN EASY METHOD

and we almost envy the sensation of delight which must be
experienced on using this simple means of illumination, and
beholding for the first time the wonderful markings and
brilliant colouring of many of these dust-like atoms, found
alike in the clearest waters, in the strongly acidulated, and in
the salt fluids of the various zones of the earth. “ In springs,
rivers, lakes, and seas, in the internal moisture of living
plants and animal bodies, exists,” says Pritchett, “a world,
by the common senses of mankind unperceived ; for, in the
ordinary pursuits of life, this mysterious and infinite kingdom
of living creatures is passed by without knowledge of, or
interest in, its wonders.” To facilitate the imvestigation
of these wonderful organizations the present paper has
been written.

The discovery of this method of exhibiting the Pleurosigma
angulatum was perfectly accidental, and so far as I know it
has not been published; at any rate, Messrs. Powell and
Lealand were wholly unaware that such an effect could be
produced, on my communicating it to them.

With many microscopes is furnished, for the purpose of a
dark-ground illumination, what is called a “ spotted lens ;” by
this means the object itself appears beautifully illuminated,
while the entire field by which it is surrounded is perfectly
dark ; the effect is produced by preventing any rays of light,
reflected from the mirror, passing through the object: this is
accomplished by placing a dark stop beneath the latter. The
arrangement, however, is such, that any oblique rays will
impinge upon the object, and after they are refracted by it,
they will pass into the object-glass ; consequently, the result
being, that the only rays transmitted through the instru-
ment, are those thus refracted from the object, it appears
beautifully bright whilst the surrounding field is black, The
accompanying engraving explains the instrument used by
myself, the cost of which was only 7s. 6d.: a, the brass
tube, fitting either into the usual brasswork of the achro-
matic condenser of Smith and Beck, by which it can easily
be moved up and down and correctly adjusted; or, as in the
microscopes of Mr, Salmon, into a small piece of tube
adapted to the diaphragm ; 4, the lens removed from the
tube. The drawings are the exact size of the different parts
of the apparatus,

This instrument is usually employed with the lower powers
(the inch and two inches), when the appearance is that already
described. On using it with a quarter constructed for me by
Mr. Ross, the angular aperture of which is 85°, with a 1-5th
of Smith and Beck’s (angular aperture of 100°), and with a

OF VIEWING CERTAIN OF THE DIATOMACEA. 207

very beautiful 1-8th (angular aperture 126°), made for me a
few months ago by Powell and Lealand, I was astonished to
find a field perfectly clear and white, and the illumination
little, if at all inferior, to that produced by Gillet’s con-
denser, or the one I generally use myself, which was made
for me by Smith and Beck. The first object I tried it with
was Pleurosigma angulatum (the Navicula angulata of
Quekett), which after a little trouble I was enabled to exhibit
most beautifully in dots; and two experienced friends, Dr.
Branson and Mr. Gregory, in common with myself, were much
struck, not only with the very beautiful manner in which the
object was shown, but also with the rapidity with which
the adjustment could be effected.

An experienced artist, Mr. C. J. Fleming, has carefully
sketched, from my microscope, the actual appearance of the
objects shown with this peculiar illumination, which at once
places in the hands of every student a ready and very cheap
method of exploring a field abounding with objects of the
most wonderful forms, and the internal structures of which,
as organized living beings, cannot fail amply to repay the
most diligent research.

These drawings, most beautifully engraved by Mr. Tuffen
West (Pl. XIII.), will show the student what he has to look for,
and so far as I know they give a better representation of ees
beautiful objects than any yet published; for however well
calculated the plates in the works of Quekett, Pritchett, or
Smith, are to show the forms of the different Diatomacea, they
fail, to my eye, to do justice to the wonderful appearances
actually exhibited by these shells. Perhaps it should be added
that the glass I generally use is an eighth, constructed by
Powell and Lealand; with a 1-5th of Smith and Beck, or a
1-4th of Ross, the markings may also be very well seen. 'The
light was obtained from the very complete gas lamp of Mr.
Highley.

In order to show these objects in a satisfactory manner,
the most careful manipulation is required; they must be

208 ON AN EASY METHOD OF VIEWING DIATOMACEZ.

covered with the thinnest possible glass, and the slide should
be perfectly clean and free from damp, otherwise the field
will have a milky appearance. In using the spotted lens,
every part of the microscope must also be perfectly clean and
free from dust; the concave mirror should always be used with
it. When due precautions are taken, points of structure can
with its aid be easily made out not seen by the ordinary
methods of illumination.

What may be the exact nature of the strie is not easy to
determine. ‘* Whenever,” says Mr: Quekett, “these infu-
soria are viewed under the most favourable illumination,
either from a white cloud or a lamp with direct light, and a
magnifying power of at least 1,200 diameters, the lines are
all shown to be dots or elevations from the surface.” * The
Rev. W. Smith ft considers the true character of these mark-
ings to have been mistaken: ‘‘ some observers having consi-
dered those appearances to arise froma series of perforations,
others from rows of beads or minute elevations.” From the
close manner in which the strie are arranged, their resolution
is amongst the most difficult tasks in microscopy. After
having given to the subject no little care and attention, with
an eighth object-glass made by Messrs. Powell and Lealand
(the beautiful defining powers of which it is impossible to
estimate too highly), | and a very deep eye-piece, I have little
hesitation in now concluding with Mr. Smith that the form of
these markings is hexaconl:

In speaking of these curious structures it will be seen that
the division of Mr. Smith has been followed ; and that the
genus Navicula of Kitzing is divided into Wavicula, distin-
guished by the delicacy of the strie, and their moniliform
character ; Pinnularia, from the strie, owing to the confluent
nature of the cellular structure of its epiderm, having the
appearance of distinct costa; and Pleurosigma from the
characteristic curve of its beautiful frustules.

* Quekett on the Microscope, 2nd Edit., p. 475.
t+ Smith, vol. i., pp. 61, 62.

MEASURING THE MAGNITUDE OF MICROSCOPIC OBJECTS. 209

On Derinine the Position and MrAsurine the MAGNITUDE of
Microscopic Oxsects. By the Rev. W. Hopeson, M.A.,
Incumbent of Brathay.

Ir is a matter of great practical convenience that the Micro-
scopical Society have adopted, as one of their standards for
size, a slide which measures exactly three inches by one. Of
the three square inches thus fixed upon, the middle square
inch is that which alone is employed to carry the object.
The inch on the right hand is appropriated to the label, or
mame; that on the left may be given up to registering the
position of any object, or may be left unoccupied altogether.
The middle square inch, therefore, is the only one to which
any measurements need refer. Let, then, the bounding lines
of this square inch at the bottom and on the left hand be
taken as what geometers would call the axes of rectangular
co-ordinates, or what, in the language of map-makers and
geographers, would be the equator and the first meridian, and
let the measurements be made in hundredths of an inch,

If an object, P (fig. 1), upon a slide represented by the dark
thick lines of the figure, were distant from AC by 67-100ths
of an inch, and from AB 39-100ths, a geometer would at
once understand its position from the values z = -67 and
y = °39, and the geographer would know what situation was
intended by long. 67° and lat. 39°.

In order, therefore, to define the place of any object on a
slide, two numbers are all that are essential.

The next step is to bring the point thus defined into the
centre of the field of the microscope. In all modern micro-
scopes, of even the most moderate pretensions, the optical
axis of the instrument will, if produced, pass through the
centre of the stage ; so that there exists already, in every such
microscope, a fixed point for the origin of co-ordinates, or
for the intersection of our microscopical equator and _ first
meridian. With the assistance of a diametral cobweb-line in
the eye-piece of the microscope, the point A (fig. 1) of the
slide, which is situated exactly one inch from its left-hand
extremity, may be brought accurately to the centre of the
stage, so that AB and CDA coincide respectively with the
horizontal and yertical lines through that point. The mea-
surements, therefore, which before were referred only to the
middle square inch of the slide, may now, by means of gra-
duation, be transferred to the stage of the microscope, or to a
supplementary stage with the name of “a finder.”

In the simplest case of a plain stage, a piece of sheet brass,

210 HODGSON, ON MEASURING THE

zinc, card, or other material, four inches by two, is prepared
with a central hole of one inch in diameter, and fitted, with
ledges, pins, springs, or some such contrivance, to the stage
of the microscope, in such a condition as to allow the glass
slide to be moved over it in various directions without dis-
turbing its position. An empty slide, on which the line AC
has been drawn with a common writing diamond, is brought,
with the help of the cobweb line in the eye-piece, into the
situation shown at fig. 1. The lines HI, H K, which are
merely the prolongations of the lines A H, GH given by the
edges of the slide, are graduated into tenths and hundredths
of an inch, and numbered both ways from H.

In order to bring an object, P, defined by long. 67° and
lat. 39°, into the centre of the field, place the slide so that
the edge GH cuts the scale H 1 at the 67th division,
while the edge H A cuts the other scale at the 39th division,
as shown in fig. 2. It is desirable to have the graduation of
HK repeated at LM, as an assistance towards keeping the
line A B parallel to its former position. With a plain stage,
the above plan is sufficient for those whose eyes can deal
readily with hundredths of an inch, and whose fingers can ~
easily make adjustments with the requisite nicety.

When the stage is fitted (as in the Students’ Microscopes of
Messrs. Smith and Beck) with dove-tailed grooves, in which
a frame for steadying the slide moves up and down, the
position represented in fig. 1 is obtained with more ease than
with a stage entirely plain. There is also a further advan-
tage in this case, by which minute dividing may be dispensed
with, without any sacrifice of accuracy. The moveable frame
may have attached to it a piece of thin brass, about an inch
broad, and on this the graduation H I, fig. 1, may be replaced
by a diagonal scale reading to hundredths of an inch, while
the edge on the right hand, or in some other convenient posi-
tion, may carry a vernier, divided as in the common baro-
meter, by which divisions of tenths on the edge of the stage
may be read to hundredths, instead of having recourse to such
minuteness as is required for the plain stage at H K.

Indeed, minuteness of division may be altogether dispensed
with, even for the plain stage, by adopting the form of Indi-
cator represented in fig. 3. The principle involved is precisely
the same as that employed in fig. 1, and the only difference in
the application of it consists in substituting two diagonal
scales reading to hundredths of an inch, for the other smaller
and less convenient graduations. The divisions in this ease
are so large that, with a flat rule and a writing diamond, the
lines may be readily drawn in a few minutes upon a piece of

MAGNITUDE OF MICROSCOPIC OBJECTS. 211

glass of proper size placed over fig. 3: and if the lines across
and near the centre are drawn by very light touches, so as to
be scarcely visible to the unassisted eye, the centreing of the
instrument is more easily effected, while no perceptible defect
results in the illumination of the object.

More elaborate instruments, possessing movements in hori-
zontal and vertical directions by means of fine screws with
micrometer heads, have already the powers requisite for
defining the place of an object, when once the commencing
position, fig. 1, has been carefully ascertained, and either
marked upon the instrument or registered for reference.

The principle, therefore, is simple in its character as well
as perfectly general in its application, and supplies the want,
which has been expressed, of a “ Universat INpicator ” for
the microscope.

With reference to the measurement of the magnitude of
microscopic objects, I have to suggest a modification of the
ingenious and elegant micrometer of Welcker, described in
No. XIV. of the Microscopical Journal, by which all gradua-
tion is dispensed with, except such as is found upon the
ordinary scales supplied with the commonest sets of mathe-
matical instruments, viz., a scale of half-inches divided to
tenths and hundredths. By means of cross-lines drawn on
the diaphragm of the eye-piece, and with a stage micrometer
divided to hundredths and thousandths of an inch, the radius
of the circle traced out by the intersection of the cross-lines
is carefully measured. The positions C D, ed (fig. 4), show
the method of effecting this; and if it should be found that
the radius of the dotted circle does not coincide exactly with
some number of thousandths of an inch, this inconvenience
may be easily rectified by means of the draw-tube. For
example, in an instrument which I have recently applied to a
Student’s Microscope by Messrs. Smith and Beck, the radius
of the dotted circle was found to be +0145 inch very nearly :
by drawing out the tube to the extent of 3:4 inches the radius
was measured exactly by «OL inch.

The modification which I propose for the external part of
Welcker’s instrument consists in substituting a right-angled
triangle for the circular sector, and suppressing all graduation.
A glance at fig. 5 will explain the matter at once. The angle
at E is a right angle, and the distance O E is exactly five
inches. The method of measuring the object is shown in
fig. 6. The object is brought so that one extremity of it is at
the intersection of the cross-lines, while the index O F coin-
cides with the line OE on the triangle. By the rotation of
the eye-piece, the diametral line is made to touch the other

212 MEASURING THE MAGNITUDE OF MICROSCOPIC OBJECTS.

extremity of the object, as shown by aO J, fig. 6. The index,
which is attached to the eye-piece, is by this movement brought
into the position O F, and the distance E F, when read by
means of the rule with the diagonal scale, gives the dimen-
sions of the microscopic object to three places of figures. Let
the distance E F, for example, when measured by the scale,
be 3°45 half-inches; this gives at once as the- length of the
microscopic object 00345 inch,

When a higher power was applied to the microscope, the
radius of the dotted circle was measured exactly by *004 inch
on the stage micrometer ; but if the radius is accurately known
in thousandths of an inch, there is no difficulty in adapting
the method above suggested to this or any other radius.
Suppose, for instance, that an object, much smaller than the
former, from its being more highly magnified, still appears of
the same size as M N, fig. 6, and that the reading given by
the scale is as before 3°45 half-inches, then the length of the
object will be, not -00345 inch, but a quantity bearing the
same proportion to it that 4 does to 10: nothing more,
therefore, is requisite than to add a cipher to the left and
multiply the result by 4: thus -000345 inch x 4 = *000138
inch, which is the length of the object.

For those who prefer greater accuracy and more expen-
sively-divided instruments, the plan of measuring by the
tangent is more easy in manipulation, and the trigonometrical
calculation is more simple, than when the chord is employed.
The equation,

log. MN = log. OM + log. tan. MON,

gives all that is necessary at once; and if the radius O M be
unity, it is sufficient to find the number corresponding to the
log. tan. of the degrees and minutes, Kc. of any observed angle.
In the case chosen above, the angle M O N was taken to
be 19°, of which the log. tan. = 9°536972, and the number
corresponding with this gives, for the length of MN,

with the lower power, * 034432
and with the higher, *00137728.

The error, therefore, by the plan now proposed, is less than
one ten-thousandth part of an inch in the one case, and less
than one hundredth-thousandth in the other. The triangle
can be made of wood, brass, zinc, card-board, or any other
suitable material, and is recommended on the score of cheap-
ness, portability, facility in use, and accuracy of result,

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TOMES, ON THE DEVELOPMENT OF THE ENAMEL. 213

On the Devetopment of the Enamet. By Joun Tomes,
F.R.S., Surgeon-Dentist to the Middlesex Hospital.

(Continued from page 104.)

Berore proceeding with this article, which was commenced in
the last Number of the Journal, I must take the opportunity
afforded by the publication of the second part to correct
certain typographical errors which have crept into the last
pages of the first. The first error is somewhat important, as
it makes me contradict a previous statement. At page 102,
and in the ninth line, not is left out after the word contracted ;
and in the tenth line after the word dentine, or has been sub-
stituted for but. At the fifth line from the bottom of the
page, alteratives has been substituted for alterations. In page
103, at the twentieth line from the bottom of the page, the
word sockets has been printed instead of sections; in the
eleventh fitted for filled; in the seventh meshes for masses;
and in the fifth line from the bottom of the page, fibrilea for
fibrille. In page 104, distant will be found instead of dis-
tinct in the eighteenth line from the bottom of the page.

The latter part of the preceding paper referred to the
structure of the enamel when fully formed. It is proposed in
this communication to enter upon the manner of formation.

Mr. Huxley, in an able article published in this Journal
(No. III, 18538), entered very fully into the history of the
subject, giving a clear account of the different views which
have been promulgated, and citing the authorities for each,
Under these circumstances it will not be necessary for me to
go over the same ground. I will, therefore, refer the reader
to the pages which contain Mr. Huxley’s paper, in place of
reprinting his historical matter.*

After adopting this arrangement, that part of Mr. Huxley’s
paper which gives his own views on the development of the
enamel, together with that which has been subsequeutly
written upon the same subject, alone remains for considera-
tion.

Prior to the appearance of Mr. Huxley’s essay, it was
pretty generally believed that the enamel fibres were formed
by the direct calcification of the columns of the enamel
organ. This opinion has, however, been shaken by a dis-

covery made by that distinguished physiologist. He found

* On the Development of the Teeth, and on the Nature and Import of
Nasmyth’s ‘ Persistent Capsule ;> by Thomas H. Huxley, F.R.S.—‘ Quar-
terly Journal of Microscopical Science,’ No. III., 1853.

VOL. IV. Q

214 TOMES, ON THE DEVELOPMENT OF THE ENAMEL.

that a membrane can be raised from the surface of the
enamel, at any period during growth, by the addition of an
acid; the membrane being external to the enamel fibres
already formed, and internal to the enamel organ—in fact,
lying between and separating the two tissues. This mem-
brane Mr. Huxley regards as the membrana preformativa of
authors. He describes it as perfectly clear and transparent,
and as being continued over the dentine in those parts where
enamel has not been formed, and over the dentinal pulp where
dentine has yet to be developed, giving it in fact the position
which the basement membrane of the mucous membrane of
the mouth would occupy when the tooth-pulp is in the folli-
cular stage, and consequently in the sacular stage, supposing
such membrane to exist in the one case, and that it has not
disappeared in the other. ‘These points are shown in the
figures illustrating Mr. Huxley’s paper.

°M. Lent, a pupil of Kolliker’s, published a paper on the
development of the dental tissues, which was subjected to the
Professor for revision.* Hence it must be regarded as ex-
pressing to some extent the opinions of M. Kolliker as well as
those of M. Lent. The account there given of the development
of the enamel is in the main but a confirmation of Mr, Huxley’s
statements, the points of difference being unimportant,
M. Lent describes the so-called membrana preformativa as
structureless, but as it were indented with the ends of the
enamel fibres. His figure shows a surface impressed with
minute square depressions. Mr. Huxley gives a similar
figure. The latter author says: ‘ Neither the capsule nor
the enamel organ take any direct share in the development of
the dental tissues, all three of which—viz., enamel, dentine,
and cement—are formed beneath the membrana preformativa,
or basement membrane of the pulp.” In another place he
says: ‘ Neither the capsule nor the ‘enamel organ,’ which
consist of the epithelium of both the papilla and the capsule,
contribute directly in any way to the development of the
dental tissues, though they may indirectly.”

M. Lent believes that the enamel organ exerts some
direct influence in the formation of the enamel, and puts
forward the following hypothesis, viz., that the cells of the
enamel organ secrete a fluid, which passes through the mem-
brana prefor mativa and cee forms enamel, Be he assumes
that the secretions of individual cells are independent, each
one forming or corresponding to an enamel fibre.

* “Ueber die Entwicklung des Zahnbeins und des Schmelzes,’ von
Eduard Lent, Stud. Med. aus Hamm.’ ‘ Zeitschrift fiir Wissenschaftlichs
Zoologie Sechster Band,’ p. 121, 1855,

TOMES, ON THE DEVELOPMENT OF THE ENAMEL. 215

I have Jatterly been occupied with this subject, but have
for the most part confined my investigation to young and feetal
teeth of the human subject. I must, therefore, be understood
to speak of the enamel of human teeth.

The method of investigation has been that indicated by
Mr. Huxley and M. Lent; and in the pursuit of the subject I
have endeavoured to trace the development of the tissue with-
out reference to its homological relations, under the belief
that the structure and development of a tissue should be per-
fectly understood before assigning its place among other
structures,

The investigations were commenced upon the lower jaw of
a nine-months’ foetus, which had been in spirit for some weeks.
On placing an incisor under the microscope, the surface was
seen to be covered by the enamel organ: the addition of a
drop of dilute hydrochloric acid (one part of acid to eleven of
water) at once produced the appearance described and figured
by Mr. Huxley; that is, a membrane seemed by degrees to
swell up from the whole surface of the enamel, the outer
surface having adherent to it, by their proximal ends, the
columns of the enamel organ, The covering glass was then
removed, the acid taken up with blotting-paper, and dilute
spirits of wine substituted. ‘The next step in the investiga-
tion was the removal of the membrane raised by the acid, in
order to submit it to separate examination. This end was
effected by the aid of needles; but in the operation the part
became torn in several places, so that its sac-like form was
lost. On returning the specimen to the microscope it was
seen that the membrane had a strong tendency to roll up in an
opposite direction to its normal position on the tooth, the out-
side thereby becoming the inside of the rolls. This dispo-
sition offered facilities for examination: had it been otherwise
there would have been some difficulty in obtaining a good
view of the torn edge—an inspection of which, with the
quarter of an inch object-glass, showed the conditions given’
in fig. 1, Pl. XV. It will be observed, on examining this
figure (which is an accurate representation of a preparation
which I have succeeded in preserving), that we have on the
concave side the columns of the enamel organ, while on the
convex side the decalcified enamel fibres remain. I have failed
to discover anything like a distinct membrane interposed be-
tween the two parts. A point may be recognised where the
two graduate into each other; but this part cannot be re
garded as a membrane, as the forming-enamel fibres clearly
pass through it.

The columns of the enamel organ are, however, very readily

Q

216 TOMES, ON THE DEVELOPMENT OF THE ENAMEL.

detached, and many float off in the fluid when the part is
under manipulation, If examined in this condition, some are
found in parallel bundles, and apparently attached slightly to
each other; but many are quite unconnected (fig. 2). But
whether associated or single, each column will be found to
have a delicate small process projecting from that extremity
which was connected with the enamel, a process which would
pass through a membrana preformativa could such be shown
to exist. Immediately above the point from which the pro-
cess starts, the column has, when separated from its fellows, a
slight circumferential dilatation, as though the cylinder had
been everted at the edge when the separation was effected. A
close examination of the columns will, I think, lead to the
belief that each is composed of a delicate sheath, in which is
enclosed one or more nuclei, the interspaces being occupied
by transparent granular matter. The nuclei are usually
more distinct near the peripheral end of the columns;
the attached extremity being commonly more granular than
nucleated ; but I have seen cases in which the sheath seemed
pretty fully occupied by nuclei. After the preparation had
been kept for a few weeks, the nuclei became more faint, and
the granular matter more apparent.

Now, supposing the decalcified enamel fibres are detached
from the columns and are viewed singly, it will be seen that
the end which approached the dentine is clear and transparent,
while that which meets the columns is coarse and granular,
appearing by transmitted light of a deep-brown colour; in-
deed, but for ihe colour, it would be difficult to distinguish
the distal extremity of the decalcified enamel fibre from the
proximal end of the column of the enamel organ, fig. 3.

In many parts of the specimen the columns have been
wholly detached, leaving a surface similar to that figured by
Mr. Huxley, and described as the membrana preformativa.
_ But if we look directly at the edge of the specimen where it

is turned towards the observer, it will be seen that the enamel
fibres pass through to the surface of this apparent membrane,
fig. 4, a.

The enamel fibre, in its decalcified state, consists of a fine
transparent and structureless sheath in the part which is fully
formed, but in the distal portions, where development is pro-
gressing, the sheath appears to contain in many instances
granular matter, fig. 3.

M. Lent mentions that he had at first some difficulty in
obtaining the membrana preformativa, freed from enamel
fibres. He at length succeeded, by treating the decalcified
specimens with caustic potash or soda. No doubt the ex-

TOMES, ON THE DEVELOPMENT OF THE ENAMEL. 217

tremely delicate sheath of the enamel fibre would under such
treatment soon disappear, and he might have got rid of the so-
called membrane by a continued application of the same agent,
in which case he might as fairly have argued that no soft
tissue existed, as he has done in assuming that a distinct
membrane bounds the enamel fibres because the sheaths have
been dissolved by an alkali, before the partly-ossified distal
extremities disappeared.*

The appearances which I have described, as existing in one
specimen, may be found in the teeth of similar age in any
foetus, which has not been too long kept. Immersion in spirits
of wine for a short time, I think, favours the demonstration,
as the extremely-delicate columns of the enamel organ become
hardened, and hence keep their normal position more fre-
quently, than in perfectly-fresh subjects. Still in the latter
similar structural conditions to these 1 have described may
be observed.

If, mstead of taking an incisor, the first molar of a nine-
months’ foetus be selected, the tooth-sac will be found dis-
tended with a fluid, in which numerous nucleated cells float.
Generally the cusps of the pulp are covered by caps of den-
tine, though this is not uniformly the case at this age. In
several instances I have preserved specimens, in which one
cusp only was invested with dentine, while the others were
quite free from calcification. In the latter case the membrana
preformativa should be distinctly visible. I have not been
able, however, to see anything that conveys to my mind the
idea of a distinct and separable membrane. A slight amount
of transparent tissue may be seen extending beyond the peri-
pheral dentinal cells, but it also dips in between them, and
has all the appearance of being nothing more than the blas-

* The results of the following experiment illustrate the amount of
dependence which can be placed upon membranes, the existence of which
cannot be demonstrated otherwise than by the use of reagents, A thin
longitudinal section was prepared from the upper incisor of a rat. This
was placed for a short time in hydrochloric acid and water (one part of
acid to eleven parts of water); on removal, the acid was neutralized by a
solution of potash. When placed in the field of the microscope, it was
seen that membranes had started up from the whole surface of the prepa-
ration. Not only did a membrane part from the surface of the enamel,
but one equally distinct peeled up from the worn, masticating surface of
the tooth, while others appeared upon the surfaces which were produced in
grinding the section. ‘The membranes thus demonstrated were distinct,
clear, and transparent, but exhibited no trace of the structural characters
of the tissues from which they were derived, and of which they had
formed a part prior to the application of the reagents. In this experiment,
the action of the acid was arrested by the potash before the whole of the
section had been decalcified. The edges and surfaces were softened, but
the interior remained firm and retained its structural characters.

218 TOMES, ON THE DEVELOPMENT OF THE ENAMEL.

tema, which connects into a mass the cells of the pulp. I do
not, however, propose to go into the development of dentine
in the present article ; hence the question of the presence or
absence of a preformative membrane extending over the den-
tinal pulp, and the relations of such membrane to the develop-
ment of dentine, may be left for future discussion.

If attention be directed to the cusps in which calcification
has commenced, appearances similar to those described in the
incisor will, if similarly treated, be found, excepting only
the enamel organ, the columns of which, in this case, are
shorter than those in the more advanced tooth.

Although I have confined the description to the structural
conditions found in developing teeth in one jaw, my exami-
nations have been extended over the teeth from many feetal
jaws. The results have, however, been uniformly similar.

Assuming that the foregoing observations have been cor-
rectly made, we need have no difficulty in explaining the
manner in which the enamel is developed, and in accounting
for the appearances exhibited in the fully-formed tissue; of
which a description and figures were given in the last Number
of this Journal. The columns of the enamel organ must be
regarded as subservient to the development of the fibres, the
conversion of the one into the other taking place in the fol-
lowing manner :—The proximal end of the column becomes
calcified, not uniformly throughout its thickness, but the
outer surface or sheath first receives the salts of lime, and at
the same time the columns become united laterally. At
this point—that is, at the extreme margin of calcification—
the columns readily separate from the fibres, and leave a sur-
face which, when looked upon directly, has the appearance of
a membrane, the reticulate character of which (figs. 4 and 5)
is due to the withdrawal of the central portion of the calci-
fying column, this central portion being the process which
has been described as forming part of the detached column
(fig. 2). The calcification of the central part of the column
goes on gradually, but does not keep pace with that of the
sheath, and when calcified, presents some points of difference
when compared with the surface of fibre. Thus, in adult
tissue, the interior of the fibre dissolved before the surface,
leaving the reticulated appearance described and figured in
the last Number of the Journal. Before calcification, the
nuclei of the column appear to break up into subgranular
matter, which may often be detected at the distal ends of the
forming-enamel fibres (fig. 3). The situation usually occupied
by well-marked oval nuclei is the distal extremities of the
enamel-organ columns ; but sometimes we find examples in

TOMES, ON THE DEVELOPMENT OF THE ENAMEL. 219

which the nuclei, or bodies very like them, fill up the whole
of the sheath, and become calcified: fig. 6 illustrates this
condition, It may generally be found in the opaque white or
brown teeth frequently seen in strumous subjects. A little
practice will enable the histologist to recognize teeth which
will yield specimens like the one figured.

Many authors have noticed the transverse striation of the
enamel fibres. The structural condition I have described is
but a more-perfect development of that which is but faintly
marked in the striation, and a less-perfect development of the
enamel itself.

In looking over a series of sections of teeth, we shall not
fail to find other exceptional conditions than that I have
described, and these must be also regarded as the results of
imperfect development. I allude to the irregularly-granular
state of the enamel fibres found in patches scattered here and
there amongst highly-developed tissue. At such points the
granularity is in many specimens confined to the interior of
the fibre, the sheath appearing clear and structureless, In-
deed, this deviation from the normal state appears due to the
calcification of the columns of the enamel organ, prior to that
change by which the granularity disappears, and the fibre
becomes transparent.

Mr. Huxley has referred to the “ persistent capsule” de-
scribed by Mr. Nasmyth, and considers it to be identical with
the membrana preformativa. In several specimens which have
been decalcified, after being reduced sufficiently thin for
microscopic examination, this membrane is obviously con-
tinuous with the cementum of the fang, and in other specimens,
which have not been treated with acid, I find the membrane
thickened in the deep depression of the crown of molar teeth,
and there tenanted by a distinct lacuna, The occurrence of
these two circumstances would indicate that Nasmyth’s mem-
brane is cementum, rather than membrana preformativa. The
general absence of lacuna in this membrane is due to its want
of sufficient thickness to contain them, just as we find these
bodies wanting in the cementum of the fang when the layer
of that tissue is very thin.

Apart, however, from this apparently-structureless layer
described by Mr. Nasmyth, we may sometimes observe a
diminution in the fibrous character of the enamel at the termi-
nations of the fibres on the surface of the tooth, and also at the
terminal edge of the enamel on the neck of the tooth. In
each of these situations appearances may be found which
suggest the idea that a fluid blastema became calcified, and
that the fibres had in the process become fused, and more or

220 CONTRIBUTIONS TO MICRO-MINERALOGY.

less lost in the mass so formed. Indeed, in the situation last
mentioned, lamination of an indistinct character may take the
place of fibres ; or both the laminated and fibrous arrangement
may be replaced by a structure exhibiting little arrangement
of parts. In any case, however, this deviation from the
normal structural character of enamel is limited to the ter-
minal edge of the tissue. The development of dentine and
cement will form the subject of a future communication.

Contributions to Micro-Mineratocy. By Samuret Hieutey,
PGS. PICS Ss Ue.

INTRODUCTION.

In 1847, not finding any classification of Minerals whereby to
arrange my collection, that satisfied my mind, I laid the
scheme of a Mineral-System founded on the chemical crys-
tallographic and physical characters according to their re-
lative value, and which I conceived threw the species into
more natural groups than any of the Systems I was then
acquainted with, all being either too chemical or too physical
in their arrangements to meet the requirements of a Natural
History method, where all the characters must receive their
due share of consideration.

My scheme was based upon the isomorphous relations of
the electro-negative to the electro-positive elements, and ap-
proached more the since-published Systems of Nordenskidld,*
(which I did not become acquainted with till 1851, when that
author visited the Great Exhibition), Danat and Rose.f
This [ showed at the time to several eminent chemists and
naturalists, who advised me to publish it as a Synopsis,
which I determined on and announced (and which I trust will
be produced ere long); but the more I advanced the more I
became assured that a searching analytical inquiry must be
instituted in various departments of Mineralogical Science
before anything approaching a philosophical or logical dis-
tribution of inorganic bodies could be hoped for. Among
other things, heterogeneous masses of mineral matter, mine-
ralized plants and animals, &c., have, for convenience, been
classed as true species under the mineralizing constituent.

* Ueber Das Atomistisch-Chemische Mineral System, &c., von Nils Nor-
denskiold, Helsingfors, 1849.

t System-—Chemical Classification, edition of 1850.

t Das Krystallo-Chemische Mineral System, von Gustav Rose, Leipzig,
1852.

CONTRIBUTIONS TO MICRO-MINERALOGY,. 221

An example of this may be found in the pages of this
Journal,* in the vexed question of the Torbane-hill Mineral,
and the Microscope as an instrument of structural, physical,
micro-chemical, and crystallological research may help to
solve many more such problems in mineralogy.

For the last three years my time has been fully occupied
with other matters, but now that I again find leisure, I return
to these inquiries ; and in the pages of this Journal I propose
to publish from time to time such investigations as bear upon
the microscopical part of the subject, and which | think will
well repay the labour, for though the bibliography of micro-
scopy abounds with papers and works on Animal and
Vegetable Structure, 1 am surprised to find how very few
have been written on mineral or inorganized bodies.

The Mineral Kingdom must embrace a wider domain than
that originally set apart for it, before it can be studied with
advantage; not only must it include those aggregates of
minerals and mineralized masses which are now regarded as a
distinct branch of study under the term Petralogy, or which
are included with Geology, but also the so-called artificial
products of the laboratory and the smelting furnace ; for where
exists the difference between the crystallogenic forces that
produce the Cyanoss of the mines and the Sulphate of Copper
of our laboratory capsules? How should we know that
Sulphur is dimorphous without resort to the crucible? or
that iodides, bromides, chlorides, and fluorides form isomor-
phous groups if we did not take cognizance of laboratory
products? As well might modern Botanists and Zoologists
ignore the extinct forms of former epochs wherewith they
now fill up many a gap in their Systems. If Mineralogy has
of late years been drifting too much from its position as a
branch of Natural History, out of the hands of the Naturalist
into those of the Chemist,t advantage has arisen, inasmuch as
Rammelsberg and Schabus have examined a large class of
laboratory products more in accordance with the Natural
History method—the results they have recently given to the
world in two yaluable publications. {

From this point of view, then, the study of the Mineral

* See Quekett, ‘'rRansactTions, vol. ii., p. 84, Pl. II., IV., V., Highley,
JOURNAL, Vol. ii., p. 141. ‘ Is Coal a Mineralogical Species ?’—Redfern,
vol. iii., p. 106, Pl. VII., VILI., LX.

+ The British Association does not include Mineralogy in the Natural
History or Geological Sections, but in the Chemical Section ; this indicates
the point of view from which this science is regarded in England.

t Handbuch der Krystallographischen Chemie von C. ¥. Rammelsberg,
Berlin, 1855; and Bestimmung der Krystallgestalten in Chemischen
Laboratorien Producte, von Jacob Schabus, Vienna, 1855.

222 CONTRIBUTIONS TO MICRO-MINERALOGY.

Kingdom should embrace the physiography and classification
of all inorganized bodies ; and although the sphere of inquiry
would be thus greatly extended beyond the limits originally
comprehended under the term MrNnerALoGy, yet that term
might be retained with a conventional significance implying
the Natural History Method of inquiry, which embraces a
consideration of all the characters common to inorganic bodies,
in contradistinction to the strictly Chemical Method. In this
conventional use of the term Mineralogy for a wider sphere of
inquiry, | am supported (though from another point of view)
by Professor Fleming of Edinburgh.*

The Mineral Kingdom would then be naturally divided
into two broad and great divisions, viz. :—

I. HomoaentA, embracing Minerals proper, and

Il. Hererocenta, including bodies of definite chemical
composition, but of composite structure—as Coal,
Bergmehl, &c.— Mechanical mixtures of chemical con-
stituents, but of apparent homogeneous aspect, as
Obsidian—and Erupted, Sedimentary, Metamorphosed,
Conglomerated + aggregates of mineral matter, com-
prising Rocks proper.

And here it may be necessary to define my idea of the
Mineral Individual. This, as most Mineralogists are agreed,
is the crystal state, which implies a definite chemical com-
position in the constituting mass. But we have other forms
of matter to deal with, which must find a place in our
Systems: these are the amorphous, liquid and vaporiform con-
ditions of the same chemical body ; which states I regard, for
convenience of description, if not for more logical reasons, as
analogous to the metamorphic or embryonic stages of the
lower forms of animals; and as Zoologists now regard the
whole cycle of Metamorphism or Development te be neces-
sarily comprised in the description of the Animal Individual, so
do I conceive the vaporiform, liquid, and amorphous states of
the same body, as only requiring favourable conditions to be
developed into the perfect form or crystal state, to represent
the series of the Mineral Individual. Thus, steam by con-
densation passes into water; water, at a certain temperature,
passes into the amorphous or crystal state according to cir-
cumstances ; in the latter case it is HexagconaL IcE—the
perfect Mineral Individual of the series. This, perhaps, is

* On the different Branches of Natural History, &c. ; an Address to the
Natural History Section of the British Association at Glasgow, 1855:
Edinburgh New Phil. Journal, No. 5, New Series, pp. 1380-2.

+ Vide Humboldt’s Cosmos, by Sabine, vol. i., p. 236.

CONTRIBUTIONS TO MICRO-MINERALOGY. 223

better than regarding these different states, as some authors
have done, as grounds for Specific distinctions,

As crystallization gives individuality to the Mineral mass,
the CrystaL System should be the ground for determining
Specific distinctions.

From considerations of the allotropic condition of matter
in dimorphous bodies, probably each crystal form has an
amorphous state of its constituent peculiar to itself. Thus
Ruompic SuLPHUR is produced from solution at low tem-
perature, and has an amorphous state common to it at ordi-
nary temperatures. Monocuinic Sutpnur, on the other
hand, exists only at high temperatures, and there is an allo-
tropic amorphous state of sulphur that, likewise, exists only
at high temperatures.

Ordinary honey-coloured amorphous Phosphorus produces
from solution Rhombic Dodecahedrons; probably the black
amorphous phosphorus would produce, under favouring cir-
cumstances, crystals belonging to a different system. Several
other instances might be cited, but it would be out of place
to enter further on this part of the subject in the pages of this
Journal, and I therefore proceed to the consideration of the
objects more specially in view.

It is my intention to consider the subjects of these contri-
butions under the following heads or parts :—

Ist. Tue InstrumMENTs oF Micro-MINERALOGICAL RE-
SEARCH.

2nd. Micro-CrystaLtocraPpuy.— Under this head I purport
describing crystal forms as seen in the field of the
Microscope,—Goniometry.—The means of determin-
ing true forms from apparent forms, caused by optical
and other deceptions. The Crystal-Systems under
which microscopical crystals may be classed. The
relation of Polarized light to the different Crystal-
Systems, and the method of measuring the angles of the
optic axes, diameter of the rings, and amount of
rotation, &c. in depolarizing crystals and inorganic
bodies, and the method of determining the Crystal-
System to which a crystal belongs, by means of
Kobell’s Stauroscope. The relation that exists between
the symmetrical grouping of crystals and the Crystal-
System to which they belong ;* and here a new field for
inquiry is open. In Vol. III. of this Journal, Plates
XIII. XIV., are figured many very beautiful groupings
* I drew attention to this subject in No. I. of ‘'The Chemist,’ New
Series, p. 58; 1853.

224 CONTRIBUTIONS TO MICRO-MINERALOGY.

of. Snow Crystals, throughout all of which Hexagonal
Symmetry prevails. I would draw especial attention
to fig. 14, a combination of obtuse Hhombohedrons,
with a central Hexagonal Prism: the relation of the
forms, and the symmetry of the grouping, is in strict
accordance with the Crystal-System to which Ice be-
longs, viz., the Hexagonal or Rhombohedric. These
symmetrical groups have been classed as twin-crystals,
a category to which I fancy, on a broader view of the
subject, they will be found not to belong.

3rd. Mrcro-CrysTaLLOGENY, comprising the influence of
foreign bodies, light, heat, electricity, magnetism, &c.,
on crystallization as viewed in the field of the Micro-
scope.

4th. Micro-ANALysIs, comprising methods of Structural,
Chemical, and Physical examination of inorganic
bodies, where the microscope is necessary as an aid to
the eye; under this head will be given the method of
determining the Indices of Refraction in minute
prisms, &c.

5th. Micro-Mineraxocy. In this section will be given a
systematic Microscopical examination of mineral bodies,
from the simplest to those of the most complex
chemical composition, for the purpose of separating
from the true mineral Species, those that are of hetero-
geneous structure, and belong more strictly to the nature
of rocks. The following divisions suggests themselves :

Division—HETEROGENIA.
(Groups determined by Micro-Analysis.)
OF DEFINITE CHEMICAL CoMPosITION.

A.—Composed of two or more varieties of the same Species, or allied Spe-
cies associated in bands, concentric layers, &c., of which many
AGATES are a type.

B.—Homogeneous in aspect to the unaided eye, but composed in mass of
vegetable remains saturated with mineral matter, of which Coat is
a Type; or conglomerated by mineral matter; or consisting of the
inorganic hard parts of vegetables condensed into rock-like masses ;
this group might be termed PuyTo.ires.

C.—Puyro-Zoorires, an intermediate group between this and the next,
the organized constituents being a mixture of vegetables and animal
remains, of which BERGMEHL is a Type.

D.—Zoouites, the organized constituents being animal remains entirely,
of which CuaLk is a Type.

[Part I. will appear in our next. |

( 225.)

REY IE Ws;

Ropiments oF ParuoLogicaL Histonocy. By Carn Went, M.D., &e.
Translated and Edited by Grorar Busx, F.R.S. (Printed for the
Sydenham Society.)

Tuer Sydenham Society has done unspeakable service for the
medical profession by presenting its members with numerous
works on Anatomy, Physiology, Medicine and Surgery, in an
English form, which, but for it, would ever have remained in
this country sealed books, unread and perhaps unknown to the
vast majority.

One of the great defects, we might almost call it an inevi-
table defect, in medical education, is its partialness—its one-
sidedness. The large amount of scientific study necessary in
medical education, the few years allotted to learning, and the
early age at which most young medical men are compelled,
from circumstances, to spend their whole time in the practice
of their profession, preclude almost the possibility of anything
like a complete general education, and but a small proportion
of the members of the profession will be found well conversant
with some of the languages of Europe in which many of the
most important works of the present day are written. These
observations are especially applicable to the German language—
and in the German tongue have appeared recently many of the
most important publications that have ever been issued upon
subjects connected with the medical profession.

Not the least valuable of these is the work now before us.

The title of Wedl’s work—‘ Rudiments of Pathological
Histology,’ is not absolutely correct, and does not do full
justice to its real character. It is not rudimentary; for the
subjects of which it treats are well considered in all their
length and breadth; and although histological descriptions
constitute the bulk of the letter-press, and the great majority
of the illustrations refer to structures as seen with high magni-
fying powers, still there are interspersed many admirable de-
scriptions of coarse pathological anatomy, and much interesting
generalization ; and among the figures are many illustrative of
structures as seen by unaided vision.

Again, the work has not the completeness which its general
and comprehensive title would seem to imply: the literature
of the several subjects treated of is very imperfect, and indeed
no effort seems to have been made on the part of the author to
render it otherwise : that was evidently not his object.

226 ON RUDIMENTS OF PATHOLOGICAL HISTOLOGY.

What Wedl’s work truly is, and what it might, in a some-
what lengthy title, be styled, is— The records of the labours of
a single individual in Pathological Anatomy in which Histology
has been chiefly considered. (n this circumstance lies the great
value of Wedl’s book—its originality: he has observed for
himself, described for himself, thought for himself, and, what
is of no small importance, he has illustrated for himself. Thus
it is that his observations have a circumstantial importance,
and his faithful records become a truthful authority, so valuable
for future reference. The general scope of the work may be
best described in the Author’s own words—

“The plan followed in the work has been the giving, in the first place,
as a methodical fourtdation, general morphological views and theories of
development with respect to exudations, atrophy, hypertrophy, the forma-
tion of inorganic and of organic substances, and particularly of new-formed
elementary organs and their various combinations.

“In the special part the subjects treated of are arranged in families : I. In-
organic formations; Il. Atrophies; III. Hypertrophies; IV. Exudations;
V. New formations; VI. Parasites.”

Mr. Busk, in his translation, has omitted, and we think very
judiciously, all notice of the Chapter on Parasites, which really
have nothing to do with pathology.

It is not our purpose to dwell farther upon Dr. Wedl’s
labours ; and we will only add that we entirely agree with his
translator’s remark, that—“ the extent of original information
and original illustration in his work will always entitle it to a
high place.”

On the manner in which Mr. Busk has fulfilled his task of
translating and editing this volume we need scarcely remark.
We have not only to thank him for an agreeable and facile
translation of the original text, but for many valuable annota-
tions in the form of foot-notes, for a voluminous index, and a
copious table of ‘contents’ appended to the volume. There
is, however, one point in which, we think, he has not used his
editorial functions with his usual judgment: he remarks at the
end of his preface—* The descriptions of the figures, usually
placed at the bottom of the page, are here given together at the
end of the book-— an arrangement which it is hoped will be found
convenient for reference.” We really do not see in what this
is more convenient than the old method; indeed we have found
it decidedly inconvenient, and we should have preferred cast-
ing our eyes from the figure to the bottom of the same page,
for the description, to the somewhat tedious process of referring
backwards and forwards over some hundreds of pages for the
same purpose.

We fear, however, that we may be accused of hypercriticism
in noticing this trivial objection amid such general excellence.

THE MICROGRAPHIC DICTIONARY. 227

Here we should close our brief notice of this work, but there
is one passage in the translator’s preface which we cannot pass
without reference: we allude to the observations he makes on
the cell theory of tissue-development, and in which we most
heartily concur. Mr. Busk remarks—

“The almost blind obedience at present paid to the doctrines of Schwann
and Schleiden has apparently acted for some time as a damper upon original
thought on the subject. Attention, however, having of late been directed,
more particularly by Mr. Huxley, to the foundation upon which this doc-
trine is based, and to the many and weighty objections to which it is
obnoxious, will, it is to be hoped, awaken a more scrutinising and inde-
pendent spirit of inquiry ; when, and not till when, we may hope to see
general, and with it Pathological Histology, placed on a firm basis.”’

We are only too glad to endorse the opinions here implied,
and to express our surprise that clear-sighted and conscientious
observers can be found who still defend the old cell-develop-
ment theory absolute and unqualified.

THe MicrocrarHic DicTIONARY ; A GUIDE TO THE EXAMINATION AND
INVESTIGATION OF THE STRUCTURE AND Nature or Microscopic
Ogsects. By J. W. Grirritn, M.D., &c., and A. Henrrey, F.R.S.,
&c. London. Van Voorst, 1856; pp. 696; with 41 Plates by Tuffen
West, and numerous Woodcuts.

WE congratulate our readers upon the completion of this
laborious and valuable work, whose peculiar nature renders a
notice of it in our pages almost imperative. Anything like a
critical review, however, of such an extensive encyclopedic
volume is obviously impossible within our necessarily con-
fined limits. Nor, perhaps, since the work has been, in part
at any rate, long before the public, is such a review now
demanded. But we think it incumbent upon us to point out
in brief terms what we conceive to be its more striking
merits and demerits, and how nearly its execution corresponds
with the conception implied in its title; and to what extent it
will prove specially useful to the general microscopic
observer, for whom alone we take it to be intended.

The Authors state that it is “offered as an index to our
knowledge of the structure and properties of bodies revealed
by the microscope.” This sentence may be taken to mean,
either that the work is intended to represent an index of what
is known respecting the microscopic structure and (micro-
scopic) properties of all bodies, or of what we know re-
specting the structure and properties of all microscopic
bodies. In neither sense, however, it is clear, does it come
up to this ambitious aim. Such a field is too vast to be
occupied by any single work of many times the dimensions of

228 THE MICROGRAPHIC DICTIONARY.

the ‘Micrographic Dictionary,’ and too varied to. be satis-
factorily cultivated by one or two individuals, however well
qualified. We find no fault, therefore, with the work in that
it has fallen short of the promise above quoted, but we may
be allowed to express some regret that the object expressed
in the title of the book has not been more closely adhered to.

A very useful and interesting work would be one including
plain and succinct accounts of the usual objects belonging
either to the organic or inorganic world, of a size so minute
as to require the aid of the microscope for their correct
examination—of objects which come under the observation,
not so much of the natural philosopher only, as of the
general class of observers who employ the microscope as
much as a means of intellectual and instructive amusement
and occupation as for the more serious purposes of study,
The real student will resort to other sources of instruction
than the pages of a Dictionary; and we fear that, notwith-
standing its many excellences, the general microscopist, as
he may be termed, will find much redundant matter in the
present work not very useful to him, and will look in vain
for many things which, as we conceive, he would have a
right to expect in its pages.

The introductory observations on the “use of the micro-
scope and the examination of microscopic objects,” refer
chiefly to the construction and mode of using the instrument
and to the methods commonly employed in microscopic
manipulation. In these, we observe nothing noyel or calling
for remark, except, perhaps, an implied recommendation to
microscopists to use glass slides measuring 2} x 1 inch
instead of those of the now universally adopted dimensions of
3 x 1 inch. This “mischievous recommendation,” as a
zealous correspondent terms it, we hope no one will incon-
venience himself and others by following. Besides these
introductory chapters, the work consists of short notices of
various objects taken, apparently, in some measure at random
from the animal, vegetable, and mineral kingdoms.

The main bulk of the Dictionary consists of botanical
articles. These include a great range of subjects, though
chiefly having reference to the lower cryptogamic plants, and
they include a considerable amount of valuable and original
information. The principal fault we have to find with this
department of the work is its very needless bulk, which is
caused by the admission of numerous things of no use or
interest whatever to the microscopical observer, nor, in fact,
to any one, and which seem to be quite out of place where
they are found, As a sort of imperfect ‘“ Conspectus

THE MICROGRAPHIC DICTIONARY. 229

Generum” of cryptogamic plants, these articles may have a
certain value to the botanist, who will most probably,
however, seek his information elsewhere; and of what use,
we may ask, to the physiologist or histologist, or to the
general microscopic observer, are such notices as these ?—
“ Drepanophyllee, a family of acrocarpous Mosses;_con-
taining one East Indian genus, Drepanophyllum, Rich.,
imperfectly known ;” or, “ Dryostachium, J. Sm., a genus of
Polypodiee, with very much branched, anastomosing veins,
with free branches in the meshes ;” or, “ Fadyenia, Hook., a
genus of Nephrodiee (polypodzous Ferns); exotic.”—Oft
which hundreds might be extracted. In general, however, the
botanical articles appear to have been judiciously selected,
and the descriptions are clear, correct, and well illustrated.
The articles having reference to the animal kingdom, much
fewer in number, also include a great amount of matter
which seems to us nearly useless where it is given. Surely
matters more interesting to those for whom the Micrographic
Dictionary is especially adapted might have been selected
than those taken from Kdlliker’s ‘Microscopic Anatomy of
the Human Body,’ with the large and well-known woodcuts
given in that work. What, again, is the use of occupying
two whole pages with an antiquated tabular view of the
animal kingdom, in which, by the way, we observe that the
Dugong is parted from its old congeners, the Cetacea, and
placed among the Pachydermata, whilst the Shrew (Sorex) is
made to forget its Insectivorous relatives, and figure among
the Rodents? Its hair alone, to adopt a microscopic test,
would show that it was an intruder there. The Polyzoa
(Bryozoa) still range with the Polyp?, and numerous micro-
scopic creatures find no place at all in the list. Of what
service, also, are such notices as those of Calia, Caliqus,
Caryophylleus, Caseine, Cecrops, Filaria, Platinum, Che-
mistry, and many others, which occupy so needlessly much
valuable space? Other matters, as, for instance, ‘* Polarized
light,” of great interest to the microscopist, and upon which
he is sure to demand information, are treated in the most
cursory way. The article on that subject conveys no informa-
tion whatever, and yet it might have been made, in a short
space, both interesting and useful. The execution, moreover,
of several articles more fully given is by no means what it
might be. As an instance of the extent to which the con-
fusion of totally distinct things under one term may be
carried, we would cite the article “ Polypi,”’ which contains
nearly as many errors as lines. Under the head of Grantia
no mention is made of Mr. Bowerbank’s interesting and
VOL Ly. R

?

230 THE MICROGRAPHIC DICTIONARY.

important discovery of the seat and nature of the ciliary
action so manifest in that sponge. The notice of Sponge,
again, is very imperfect, and in the description of the figures
the ees: of the sponge spicules are termed the apices, and
vice versa. In the Acalephe the arms, tentacles, &c., are
stated to be covered with cilia, and the class generally is said
without any hesitation, to be furnished with a distinct nervous
system, and with blood-vessels containing coloured blood,
distinct from the chy laqueous channels, although under the
head of “chylaqueous system,” Dr. Williams’s assertion is
adopted, that a separate blood vascular system is not found in
any form, even in the most rudimentary, below the Eehinoder-
mata, ai the Acalephe are particularly noticed as not pos-
sessing one. The omissions, however, in this department of
the dictionary are of still greater importance. We look in vain
for the words Bryozoa or Polyzoa, a class of animals wholly
microscopic, and containing forms of the greatest variety,
beauty, and interest, abounding.s in the sea and in fresh waters,
and together with tee equally neglected Sertulariadans, the
constant objects of never-ending, pleasing observation to the
young and old microscopist.

If half the botanical articles (in number) had been omitted,
and many of those relating to the animal kingdom, including
nearly all those on human histology, which are quite out of
place in the micrographica! dictionary, room would have been
afforded and to spare for matters such as the above, and
numerous others, of far greater interest and value to the large
class of general readers, for whom such works as the Micro-
graphic Dictionary are specially intended.

Having thus shown what we regard as the defects in the
Micrographic Dictionary, the more pleasing and longer task
would remain had we space to indicate its merits. As we
have said, the great bulk of the articles are valuable and well
selected, and it is impossible to commend in too high terms
the way in which the book is “got up.” Itis enough, perhaps,
to say that it is worthy of the publisher, printer, and artist.
The illustrations are copious, clear, and well selected, and
alone would confer great value upon the work, which we
strongly recommend to all who may require a compendious
summary of what is known on a vast variety of interesting
microscopic objects, and assistance in the mode of pursuing
microscopic researches,

DR. CARPENTER, ON THE MICROSCOPE. 231

Tue Microscope AND ITs REVELATIONS. By WiiitAm B. Carrenter,
M.D., F.R.S., &c. London. Churchill.

Ir was only to be expected that if Dr. Carpenter undertook to
write a book on the Microscope, it would be a good one,
and at least not inferior to any that had hitherto ae pub-
lished. Such was our anticipation, and we have not been
disappointed, The book is even better than we could have
hoped for, for knowing as we do the great amount of literary
and teaching labour performed by Dr. Carpenter, we are
astonished ie find that he could secure the time for producing
a book in every way so complete and faithful a transcript of
the subject to which it is devoted as the present volume.
This work is not, in fact, as its name might seem to imply,
a simple introduction to the use of the Microscope, but a
treatise on this instrument, describing the principles of its
construction, the various forms which are employed, their
adaptations to special uses, and a survey of the various depart-
ments of science in which it has been successfully employed.
The introduction consists of a sketch of the service rendered
by the Microscope to science. ‘The author indicates here the
various facts observed by means of the Microscope, and points
out their value as the foundation of philosophical reasoning
in all those classes of phenomena to which they are related.
We should have been glad to have quoted the whole of the
concluding part of these observations devoted to the educa-
tional value of the Microscope. ‘They are so applicable to
the educational demands of the present day, and so in accord-
ance with the aspirations of those who regard science and
scientific research as only means to the higher end of the
intellectual and moral development of man, that we can but
commend them to all interested in the subject of education.
We must, however, find space for the introductory remarks,

* All the advantages which have been urged at various times, with so
much sense and vigour,* in favour of the study of Natural History, apply
with full force to Microscopical inquiry. What better encouragement and
direction can possibly be given to the exercise of the observing powers of a
child, than to habituate him to the employment of this instrument upon
the objects which immediately surround him, and then to teach him to
search out novelties among those less immediately accessible? The more
we limit the natural exercise of these powers, by the use of those methods
of education which are generally considered to be ‘specially advantageous
for the development of the Intellect,—the more we take him from fields
and woods, from hills and moors, from river-side and sea-shore, and shut
him up in clese school-rooms and narrow play-grounds, limiting his atten-
tion to abstractions, and cutting him off even in his hours of sport from those

* By none more forcibly than by Mr. Kingsley, in his recent little volume en-.
titled “ Glaucus, or the Wonders of the Shore.”
R 2

232 DR. CARPENTER, ON THE MICROSCOPE

sights and sounds of Nature which seem to be the appointed food of the
youthful spirit,—the more does it seem important that he should in some
way be brought into contact with her, that he should have his thoughts
sometimes turned from the pages of books to those of Creation, from the
teachings of Man to those of God. Now if we attempt to give this direc-
tion to the thoughts and feelings in a merely didactic mode, it loses that
spontaneousness which is one of its most valuable features. But if we
place before the young a set of objects which can scarcely fail to excite
their healthful curiosity, satisfying this only so far as to leave them still
inquirers, and stimulating their interest from time to time by the disclo-
sure of such new wonders as arouse new feelings of delight, they come to
look upon the pursuit as an ever-fresh fountain of happiness and enjoy-
ment, and to seek every opportunity of following it for themselves.
“here are no circumstances or conditions of life, which need be alto-
gether cut off from these sources of interest and improvement. Those who
are brought up amidst the wholesome influences of a country life, have, it
is true, the greatest direct opportunities of thus drawing from the Natural
Creation the appropriate nurture for their own spiritual life. But the very
familiarity of the objects around them, prevents these from exerting their
most wholesome influence, unless they be led to see how much there is
beneath the surface even of what they seem to know best; and in rightly
training them to look for this, how many educational objects,—physical,
intellectual, and moral,—may be answered at the same time! ‘A walk
without an object,’ says Mr. Kingsley, ‘ unless in the most lovely and novel
scenery, is a poor exercise ; and as a recreation utterly nill. If we wish
rural walks to do our children any good, we must give them a love for
rural sights, an object in every walk; we must teach them—and we can
teach them—to find wonder in every insect, sublimity in every hedge-row,
the records of past worlds in every pebble, and boundless fertility upon the
barren shore ; and so, by teaching them to make full use of that limited
sphere in which they now are, make them faithful in a few things, that
they may be fit hereafter to be rulers over much.’ What can be a more
effectual means of turning such opportunities to the best account, than the
employment of an aid which not only multiplies almost infinitely the
sources of interest presented by the objects with which our eyes are most
familiar, but finds inexhaustible life where all seems lifeless, ceaseless ac-
tivity where all seems motionless, perpetual change where all seems inert ?—
Turn, on the other hand, to the young who are growing up in our great
towns, in the heart of the vast Metropolis, whose range of vision is limited
on every side by bricks and mortar, who rarely see a green leaf or a fresh
blade of grass, and whose knowledge of animal life is practically limited to
the dozen or two of creatures that everywhere attach themselves to the
companionship of Man, and shape their habits by his. To attempt to in-
spire a real love of Nature by books and pictures, in those who have never
felt her influences, is almost hopeless. A child may be interested by ac-
counts of her wonders, as by any other instructive narrative; but they
have little of 7ife or reality in his mind,—far less than has the story of ad-
venture which appeals to his own sympathies, or even than the fairy tale
which charms and fixes his imagination. But here the Microscope may be
introduced with all the more advantage, as being almost the only means
accessible under such circumstances, for supplying what is needed. A
single rural or even suburban walk will afford stores of pleasurable oecupa-
tion for weeks, in the examination of its collected treasures. A large glass
* jar may be easily made to teem with life, in almost as many and as varied
forms as could be found by the unaided eye in long and toilsome voyages
over the wide ocean ; and a never-ending source of amusement is afforded
by the observation of their growth, their changes, their movements, their

AND ITS REVELATIONS. 233

habits. The school-boy thus trained, looks forward to the holiday which
shall enable him to search afresh in some favourite pool, or to explore the
wonders of some stagnant basin, with as much zest as the keenest sports-
man longs for a day’s shooting on the moors, or a day’s fishing in the best
trout-stream ; and with this great advantage over him,—that his excursion
is only the beginning of a fresh stock of enjoyment, instead of being in
itself the whole.”

In the part of the work devoted to the description of the
Microscope, the most full and liberal account is given of the
various kinds of instruments constructed by various makers.
No one can, we think, complain that they are not fairly
treated by Dr. Carpenter. Whenever an instrument exhibits
a new feature or application it has been fully described, so
that the possessor of this volume will have an ample guide in
the purchase of the multiplicity of instruments now courting
his attention. The notice of accessory apparatus is not less
minute, fair, and comprehensive. Those who become ac-
quainted with the Microscope for the first time by this work,
will be, perhaps, somewhat dismayed at the extent, variety,
and expense of the microscopic apparatus, but let them be
comforted with the following words :—

“Tt cannot be too strongly or too constantly kept in view, that the
value of the results of Microscopic inquiry will depend far more upon the
sagacity, perseverance, and accuracy of the observer, than upon the elabo-
rateness of his instrument. The most perfect Microscope ever made, in the
hands of one who knows not how to turn it to account, is valueless ; in the
hands of a careless, a hasty, or a prejudiced observer, it is worse than
valueless, as furnishing new contributions to the already large stock of
errors that pass under the guise of scientific truths. On the other hand,
the least costly Microscope that has ever been constructed, how limited
soever its powers, provided that it gives no false appearances, shall furnish
to him who knows what may be done with it, a means of turning to an
account, profitable alike to science and to his own immortal spirit, those
hours which might otherwise be passed in languid ennw7, or in frivolous or
degrading amusements,* and even of immortalizing his name by the dis-
covery of secrets in Nature as yet undreamed of. A very large proportion
of the great achievements of Microscopic research that have been noticed
in the preceding outline, have been made by the instrumentality of micro-
scopes which would be generally condemned in the present day as utterly
unfit for any scientific purpose ; and it cannot for a moment be supposed,
that the field which Nature presents for the prosecution of inquiries with
instruments of comparatively limited capacity, has been in any appreciable
degree exhausted. On the contrary, what has been done by these and
scarcely superior instruments, only shows how much there is to be done.
The author may be excused for citing, as an apposite example of his mean-
ing, the curious results he has recently obtained from the study of the de-
velopment of the Purpura lapillus (rockwhelk), which will be detailed in
their appropriate place (Chap. x11.); for these were obtained almost entirely

* «1 have seen,” says Mr, Kingsley, ‘ the cultivated man, craving for travel and
success in life, pend up in the drudgery of London work, and yet keeping his spirit
calm, and his morals perhaps all the more righteous, by spending over his Microscope
evenings which would too probably have generally been wasted at the theatre,”

234 DR. CARPENTER, ON THE MICROSCOPE

by the aid of single lenses, the Compound Microscope having been only
occasionally applied to, for the verification of what had been previously
worked out, or for the examination of such minute details as the power
employed did not suffice to reveal.

“But it should be urged upon such as are anxious to do service to
Science, by the publication of discoveries which they suppose themselves
to have made with comparatively imperfect instruments, that they will do
well to refrain from bringing these forward, until they shall have obtained
the opportunity of verifying them with better. It is, as already remarked,
when an object is least clearly seen, that there is most room for the exercise
of the imagination ; and there was sound sense in the reply once made by
a veteran observer, to one who had been telling him of wonderful discove-
ries which another was said to have made ‘ in spite of the badness of his
Microscope,’—‘ No, Sir, it was in consequence of the badness of his Micro-
scope.’ If those who observe, with however humble an instrument, will
but rigidly observe the rule of recording only what they can clearly see,
they can neither go far astray themselves, nor seriously mislead others.”

The description of apparatus is followed by a very com-
plete account of the various methods adopted for mounting
and preparing objects.

The second part of the work consists of an account of the
various forms of animal and vegetable life, which are the
subjects of microscopic research. In this department it was
to be expected that Dr. Carpenter would display his great
knowledge of Biological phenomena, and few persons, how-
ever profound their knowledge of particular departments of
anatomical research and physiological laws, will fail to read
these chapters without adding to their stores of knowledge and
widening their sphere of thought.

This section of the work is almost a complete resumé of
the present state of our knowledge of the histology, repro-
duction, and development of the vegetable and animal king-
dom ; and Dr. Carpenter, by his general remarks, has given a
consistency and unity to these subjects, which will recommend
his book where microscopical research is not the object of
study. As a specimen of the manner in which these general
subjects are treated, we give the following :-—

“279. The Reproduction of the Rotifera has not yet been completely
elucidated. There is no instance, in this group, in which multiplication
by gemmation or spontaneous fission is certainly known to take place ; but
the occurrence of clusters formed by the aggregation of a number of indi-
viduals of Conochilus, adherent by their tails, and enclosed within a common
lorica, would seem to indicate that these clusters, like the aggregations of
Polygastrica, Bryozoa, and Tunicata, must have been formed by continuous
growth from a single individual. 'The ordinary method of multiplication,
however, is commonly supposed to be by a proper generative act ; as dis-
tinct sexes have been discovered in several individuals, and the act of
sexual union has been witnessed. The condition of the male of the re-
markable genus described by Mr. Dalrymple (loc. cit.) is a most extraor-
dinary one ; for it possesses no mandibles, pharynx, @sophagus, stomach,
nor hepatic glands; having, in fact, no other organs fully developed, than

AND ITS REVELATIONS. 235

those of generation. It would appear, therefore, quite unfit to obtain
aliment for itself; and its existence is probably a very brief one, being con-
tinued only so long as the store of nutriment supplied by the egg remains
unexhausted. In Lotifer, however, as in by far the larger proportion of
the class, no males have been discovered ; and it remains doubtful whether
the two sexes are united in the same individual, or whether the males are
produced only at certain times. The female organ consists but of a single
ovarian sac, which frequently occupies a large part of the cavity of the
body, and which opens at its lower end_by a narrow orifice into the cloaca.
Although the number of eggs in these animals is so small, yet the rapidity
with which the whole process of their development and maturation is ac-
complished, renders the multiplication of the race very rapid. The egg of
the Hydatina is extruded from the cloaca within a few hours after the
first rudiment of it is visible; and within twelve hours more the shell
bursts, and the young animal comes forth. In the Lotifer and several
other genera, the development of the embryo takes place whilst the egg is
yet retained within the body of the parent (fig. 201, &), and the young are
extruded alive ; whilst in some other instances, the eggs, after their extru-
sion, remain attached to the posterior extremity of the body (fig. 200), until
the young are set free. In general it would seem that, whether the rup-
ture of the egg-membrane takes place before or after the egg has left the
body, the germinal mass within it is developed at once into the form of the
young animal, which resembles that of its parent ; no preliminary meta-
morphosis being gone through, nor any parts developed which are not to be
permanent. ‘The transparency of the egg-membrane, and also of the
tissues of the parent Rotifer, allows the process of development to be
watched, even when the egg is retained within the body ; and it is curious
to observe, at a very early period, not merely the red eye-spot of the em-
bryo, but also a distinct ciliary movement. The multiplication of Hydatina
(in which genus three or four eggs are deposited at once, and their deve-
lopment completed out of the body) takes place so rapidly, that, according
to the estimate of Professor Ehrenberg, nearly seventeen millions may be
produced within twenty-four days from a single individual. Even in those
species which usually hatch their eg¢s within their bodies, a different set of
ova is occasionally developed, which are furnished with a thick glutinous
investment: these, which are extruded entire, and are laid one upon
another, so as at last to form masses of considerable size in proportion to
the bulk of the animals, seem not to be destined to come so early to matu-
rity, but very probably remain dormant during the whole winter season,
so as to produce a new brood in the spring. These ‘ winter-eggs’ are in-
ferred by Mr. Huxley, from the history of their development, to be really
gemme produced by a non-sexual operation; while the bodies commonly
called ova, he considers to be true generative products. Dr. Cohn has
recently informed the author, however, that he has ascertained by direct
experiment upon those species in which the sexes are distinct, that the
bodies commonly termed ova (figs. 200, 201), are really internal gemme,
since they are reproduced, through many successions, without any sexual
process, just like the external gemme of Hydra (§ 301), or the internal
gemmez of Lntomostraca and Aphides (Chap. xv1). And this view appears
to himself to be more accordant with general physiological analogy, than
that of Mr. Huxley, since, in the other instances referred to, as in the
Rotifera, the multiplication by gemmation goes on rapidly whilst food and
warmth are abundantly supplied; but gives place to the true generative
process, when the nutritive activity is lowered by their withdrawal.”

Although, of course, Dr. Carpenter has drawn largely on
the researches of others, the work contains much matter which

236 DR. CARPENTER, ON THE MICROSCOPE

may be regarded as exclusively his own. Such is his account
of the Structure of Shells, from which we give an extract re-
lating to the forms assumed by the Brachiopoda.

«©3841. The shells of Terebratule, and of several other genera of Bra-
chiopoda, are distinguished by peculiarities of structure, which serve to
distinguish them from all others. When thin sectionsof them are micro-
scopically examined, they exhibit the appearance of long flattened prisms
(fig. 259, 6), which are arranged with such obliquity, that their rounded
extremeties crop out upon the inner surface of the shell in an imbricated
(tile-like) manner (a). All true Terebratulide, both recent and fossil, ex-
hibit another very remarkable peculiarity ; namely, the presence of a large
number of perforations in the shell, generally passing nearly perpendicu-
larly from one surface to the other (as is shown in vertical sections (fig.
261), and terminating internally by open orifices (fig. 259), whilst exter-

Fig, 260.

CA

\

if

AS i

(eee

Ay
“yk

Fic. 259. Internal surface (a), and oblique section (0), of Shell of Terebra-
tula (Waldheimia) australis.
Fic. 260. External surface of the same.

nally they are covered by the periostracum (fig. 260). Their diameter is
greatest towards the external :

surface, where they sometimes Fig, 261,
expand suddenly, so as to be-
come trumpet-shaped; and it
is usually narrowed rather sud-
denly, when, as sometimes hap-
pens, a new internal layer is
formed as a lining to the pre-
ceding (fig. 261, a,dd). Hence
the diameter of these canals,
as shown in different transverse
sections of one and the same
shell, will vary according to the
part of its thickness which the
section happens to traverse.
The different species of Tere-
bratulide, however, present :
very striking diversities in the Ih :

size and closeness of the canals, heinia) australis abowing £8 aaa
as shown by sections taken in _ ing by large trumpet-shaped orifices on the onter

; z . “P4 ‘face, and contracting at dd into narrow tubes;
corresponding parts of their SiG \\t oie a 3 : ;

; g at B a bifurcation of the canals.
shells; three examples of this c . vat

kind are given for the sake of Comparison in figs, 262-264. These canal

AND ITS REVELATIONS. 237

are occupied, in the living state, by tubular prolongations of the mantle,
the interior of which is filled with a fluid containing minute cells and

Fig. 263. Fig. 264,

noe
HATA
® Hy A

Fic. 262. Horizontal Section of Shell of Terebratula bullata (fossil, oolite),
Fig. 263. Ditto . . . . . = . of Megerlia lima (fossil, chalk).
Fic. 264. Ditto . . . . . . of Spwiferina rostrata (triassic).

granules, which, from its corresponding in appearance with the fluid
contained in the great sinuses of the mantle, may be considered to be
the animal’s blood. Hence these cwcal tubes may be inferred to possess
a respiratory function; and seem to be analogous to tubes of a very
similar nature, which extend into the ‘test’? of many Tunicata from
their sinus-system (§ 834). In the family Rhynchonellide, which is
represented by only two recent species (the Lh, psittacea and Lh,
nigricans, both of which formerly ranked as Terebratulz), but which
contains a very large proportion of fossil Brachiopods, these canals are en-
tirely absent ; so that the uniformity of their presence in the Terebratulide,
and of their absence in the Rhynchonellidx, supplies a character of great
value in the discrimination of the fossil shells belonging to these two groups
respectively. Great caution is necessary, however, in applying this test ;
mere surface-markings cannot be relied on; and no statement on this point
is worthy of reliance, which is not based on a microscopic examination of
thin sections of the shell. In the families Spir¢feride and Strophonemide,
on the other hand, some species possess the perforations, whilst others are
destitute of them; so that their presence or absence there only serves to
mark out subordinate groups. This, however, is what holds good in regard
to characters of almost every description, in other departments of Natural
History, as well as in this; a character which is of fundamental import-
ance from its close relation to the general plan of organisation in one group,
being, from its want of constancy, of far less account in another.”

The illustrations in the above extract will give an idea of
the woodcuts with which the work abounds. These are all
executed by Mr. Bagg; and the whole work is got up with
the same care that characterizes Mr. Churchill’s series of
manuals.

* For a particular account of the Author’s researches on this group, see
his memoir on the subject, forming part of the Introduction of Mr. David-
son’s ‘ Monograph of the British Fossil Brachiopoda,’ published by the
Paleontographical Society.

( 238 )
NOTES AND CORRESPONDENCE.

‘he Proboscis of the Blow-fly.—Evyer since I have had a good
microscope, this has been a favourite and interesting object to
me, and partly in consequence of a photograph of it having
appeared in the third Number of this Journal, I was induced
to send the following query to the editors, which appeared in
the fifth Number, hoping that by thus calling attention to the
subject some one of competent knowledge and skill would
take it up. “Query. In what work may there be found a
description of the exceedingly beautiful structure of the
proboscis of the Fly, more especially of what are termed, in
the explanation of the Plate, in the third Number of this
Journal ‘divided absorbent tubes?” This query, unfortu-
nately, has not been noticed; and consequently, in this short
communication, I wish to direct the attention of your readers
to some points of the beautiful and curious structure of this
organ, and trust that some one learned in these matters will
endeavour to explain the functions of the parts described. I
have an additional inducement to do this since there appears
to be in published works diverse views as to the functions
of these beautiful spirals. Whilst in the description of Plate
VII. of the Transactions of the Microscopical Society, con-
tained in the third Number of this Journal, they are termed
“divided absorbent tubes,” in the ‘ Micrographic Dictionary,’
just completed, the proboscis is mentioned (article Musca,
p. 444) as being “kept expanded by a beautiful and elastic
frame-work of modified trachez.”’

Adopting provisionally the term “divided absorbent
tubes,” each tube appears to be made up, as it were, of
divided turns of a spiral fibre, which, to avoid circum-
locution, I shall call divided spirals; and in fig. 1, I have

made a very careful drawing, by the camera lucida, of a
portion of one of these tubes, magnified about 800 diameters.
But the opposed ends of these divided spirals do not termi-
nate similarly ; for while one extremity exhibits a fine point,
the other is forked, dividing into two portions, each haying a

MEMORANDA. 239

fine point, and which, together, are very nearly the shape of
a semicircle.

These simple points (A, fig. 1) and forks (s) alternate along
both sides of the line of division, the forked extremity of one
divided spiral being placed in juxtaposition with the simple
point of the adjacent fibre. It is evident that the portion
which I have endeavoured to draw, although showing this
structure very clearly, is rather distorted in the process of
mounting (mounted by Topping); but from what may be
seen in other portions of this specimen, I believe that a tube
quite undistorted would present something of the appearance
of figure 2. This very beautiful structure is obscurely indi-
cated in the positive photograph by Mr. Delves, alluded to
above. By carefully examining the proboscis with a power
of about 200 diameters, it appears as though these tubes are
connected together by a delicate, structureless membrane, not
on the same plane, with the membrane accurately represented
in figure 29a, Plate 26, of the ‘ Micrographic Dictionary ;’ in
which figure, however, the peculiar features of the “ divided
absorbent tube ” do not appear (with all due deference to the
talented Authors) to be characteristically drawn.—G. Hunt,
Handsworth, near Birmingham.

Aperture of Object-Glasses. — Professor Bailey having admitted
that the effect of balsam mounting is to cause a reduction of
the angle of aperture of the object-glass, any further remarks
from me in defence of this position are almost superfluous.

A scientific controversy should not, perhaps, be avoided, if
its sole end is to establish the truth—my arguments on the
subject in question have been entirely dictated by this motive.
If I have at all misunderstood Professor Bailey, it has not
been either intentionally or wilfully, for the few words to
which his last comments relate might readily bear the inter-
pretation that I put upon them. He stated that my argu-
ments were erroneous, and gave as the single reason that I
had “ traced the rays into the balsam instead of out of it;” I
must confess that I inferred from this that Professor Bailey
meant to imply that a ray traced outwards would be refracted
at a different angle of emergence relative to the degree of
incidence, than if the same ray was traced inwards. As this
can never be the case, and the discussion related to one point
only, viz., the aperture of the object-glass, or angle of rays
collected from an object in balsam, therefore, with all submis-
sion, I think that I was not in fault in saying that it comes to
precisely the same thing if the rays are traced into the re-
fractive medium or out of it, as far as the actual result is
concerned,

240 MEMORANDA.

The refractive effect of balsam causes but a small compara-
tive difference in favour of extreme degrees: for example,
referring to my former experiments, two object-glasses, one of
146° and the other of 105° of aperture, will be reduced over
an object in balsam to 75° and 68’, being a difference of
forty-one degrees in air, but only seven degrees in balsam. In
discussing this subject, I have omitted to mention that balsam-
mounting not only has the effect of another optical combina-
tion by the refractive medium reducing the aperture, but that
the same refraction also slightly diminishes the magnifying
power of the object-glass. This may be easily proved by
measuring the length of an object both before and after fluid
balsam has been allowed to run under the thin glass cover,
using a 1-12th objective—F. H. Wenuam.

Application of Collodion to the Production of Stage and Eye-piece
Micrometers for the Microscope.— A cheap stage-micrometer may
be made by taking a cast in collodion from a piece of ruled
glass, and mounting the cast thus taken as a microscopic
slide. The specimen sent with this is one of many casts
taken in this way from a piece of glass on which lines had
been ruled at the distance of 1-400ths of an inch. Every
irregularity in the original is accurately copied on the collo-
dion ; and by this planone correctly-ruled micrometer on glass
may be made to furnish any require dnumber of exact copies.

An eye-piece micrometer may be made in a very simple
manner, by employing the photographic camera to reduce a
coarsely-graduated original to any degree of minuteness which
may be desired. The specimens sent with this are copies of
a scale of inches and tenths, reduced in this way either to
tenths and hundredths or to twentieths and two-hundredths ;
and also of a diagonal scale reduced so as to furnish for the
eye-piece of the microscope a micrometer of which the divi-
sions are hundredths and thousandths of an inch. ‘The
originals are of glass, covered with black paper or black
varnish, on which lines were drawn with a knife-point.
These micrometers are not perhaps so sharp as those ruled
by machines, but they may be made at a much smaller cost,
of any required pattern and size, and by those who have no
machines within their reach.—W. Honeson, Old Brathay.

Note on Pinnalaria.—At the first page of this volume of the
‘Quarterly Journal of Microscopical Science, Dr. Gregory,
noticing a Pinnularia, for which he had adopted Professor
Smith’s name of Pinnularia latestriata, proceeds thus:—* I
could find no figure of this species in any work to which I
had access, neither in Ehrenberg’s Atlas in 1838, in Kutzing,

MEMORANDA. 241

nor in Rabenhorst. Nor did any English observer know it.
But I now find that Ehrenberg had described it as P. borealis,
ten or twelve years ago, although his figure, which, if pub-
lished, appeared in the Berlin Transactions or the Berlin
Monthly Reports, was entirely unknown to all our authorities
in this country, none of whom, more than myself, have been
able to consult Ehrenberg’s very numerous papers on the
Berlin Transactions or Monthly Reports, except as quoted by
Kutzing or Rabenhorst, neither of whom noticed this species.
I mention these facts to explain how it was that a species
long ago described, and I believe figured, by Ehrenberg, was
regarded by all our authorities as new when I found it in the
Mull earth two years ago.”

Allow me briefly and respectfully to state, that the Pzn-
nularia borealis is figured by Kutzing, and is figured by
Rabenhorst ; and that Kutzing copied his figure from Ehren-
berg’s American Tabula, a work by no means unknown in
this country.—J.

Ov Micrometers and Micrometry.—In the last number of the
‘ Microscopical Journal,’ there is a paper by Dr. Robertson,
quoted from the ‘ Monthly Journal of Medical Science,’ re-
commending an ingenious form of eye-piece micrometer, pro-
posed by Herman Welcher, a medical student at Giessen, on
which I wish to offer a few observations.

Micrometry, as affected by the compound microscope,
consists in the comparison of the magnified image of the
object with the similarly-magnified image of a body whose
dimensions are known, the most convenient for the purpose
being a piece of glass ruled with fine divisions, called a
stage micrometer. ‘This comparison cannot, as Dr. Robertson
correctly observes, be made directly by laying the object on
the divided scale; but it may be made indirectly, either by
the camera lucida, as practised by Mr. Lister, or by means of
an eye-piece micrometer, The latter method, in addition to
convenience in application, has the further advantage of sub-
dividing the divisions on the stage to an extent corresponding
to the magnifying power employed; but it also has the dis-
advantage of enlarging their errors in the same proportion.

In ruling a micrometer, the elasticity of the materials of the
dividing engine, the friction of its moving parts, or the free-
dom of motion necessarily allowed in order to diminish that
friction, will produce a very slight inequality in the individual
divisions ; but if these be carefully examined, their errors
will generally be found to be alternately plus and minus, in no
case cumulative. It therefore follows that the sum of the
errors of a number of divisions will scarcely ever exceed that

242 MEMORANDA.

of an individual one, and will probably be much less. The
advantage, then, of taking a large space of the stage micro-
meter as a basis for estimating the value of that in the eye-
piece is quite evident ; for, not only is the absolute amount of
error likely to be less, but that amount will be proportionally
diminished in measuring all smaller objects, whereas it would
be increased in measuring larger ones.

In the micrometer recommended by Dr, Robertson, the
object is made to occupy the chord of an arc, and the extent
that can be measured by it is the diameter of the dotted circle
described by the revolution of the point of intersection of the
lines a b and ed, fig. 2, p. 1595.

To find the value of this quantity, make the line ed parallel
and coincident with one of the divisions of the stage micro-
meter, then turn the eye-piece half round, and when the same
line is again parallel to a division, read off the number of
divisions passed over, which will be equal to the chord of
180°, or twice the size of 90°, The chord, then, of any ob-
served angle will bear the same proportion to the chord of
180°, that the sine of half the angle does to the sine of 90°;
and as the latter quantity is taken as unity in the tables of
sines, the calculation becomes quite easy, either by logarithms,
whole numbers, or the sliding-scale. Whether this instru-
ment is capable of the accuracy assigned to it by Dr. Robert-
son, must depend on the relative position of the eye-piece and
the object on the stage remaining invariable during the opera-
tion; and this can only be insured by sound workmanship
in the maker, and delicate manipulation in the observer.

The latter, however, will, I think, find some difficulty in
placing the line to be measured (which may be either in the
length or breadth of an object) in the exact direction of the
chord of the ¢maginary circle (for there is no trace of it in the
microscope) ; and the calculations, though simple, will become
wearisome when often repeated. When Dr. Pereira was
engaged on the last edition of his ‘ Materia Medica,’ I made
the measurements of the different starch-globules for him;
and as I generally measured eight or ten in each specimen, I
am sure that it would have taken me a much longer time than
I spent over it to accomplish the task with the above instru-
ment. The eye-piece micrometer that I used was a glass one,
furnished with the fine-movement screw, described in the
transactions of the Microscopical Society, and in Mr Quekett’s
treatise. It was divided into 250ths of an inch, and, by means
of a draw-tube, was made to read 10,000ths with the quarter
inch object-glass employed. The measurements may therefore
be relied on to the 30,000th of an inch; for the third, or even
fourth of a division can be easily estimated.

MEMORANDA. 243

Dr. Robertson complains that in glass micrometers “the
breadth of the lines is so considerable, and the shadows caused
by their channels are so perplexing,” that extreme accuracy is
unattainable with them.

From his constantly speaking of millimeters, I conclude
that the micrometers he has used are of French manufacture,
some of which, as I have seen, are justly liable to his censure,
for they appear to have been ruled by a diamond which cuts,
or rather splits, the glass like that employed by glaziers. But
micrometers may be obtained from most of the makers in
London, in which the lines are only thick enough to be dis-
tinctly visible ; and the channels being filled with plumbago,
and having a cover cemented over them with Canada balsam,

cast no shadows when in the focus of the eye-glass, the shadows
which Dr. Robertson complains of, being most ‘probably the
refraction of the prismatic edges of the channels.— GEORGE

Jackson, 30, Church Street, Spitalfields.

Mr. Amyot’s Finder.—You were good enough to insert a short
paper of mine on the “ Finder or Indicator” in the last
number of the ‘ Microscopical Journal ;’ I have since had
some lithographed scales struck off for pasting on the face of
the wooden instrument, and have had the pleasure of supply-
ing a considerable number of these to gentlemen unknown to
me, and to whom I have not had time to write full directions
for attaching them. Indeed it is only within the last few days
that I have hit upon a mode of effecting this with ease and
satisfaction to myself. If you would be good enough to insert
the few necessary directions which I have condensed to the
utmost, you would confer an additional obligation.

Directions for attaching the Lithographic Paper Scales to the Wooden
Indicator, described at page 151 of the last Number of the Journal.

1. Continue the lines of the four scales across the centre of the paper,
using a fine-pointed pencil.

2. Perforate the central intersection of lines with a needle.

8. Cover the face of the wooden instrument with a thin iayet of smooth
paste, the bone disk being removed.

4. Force the little brass pin out of the bone, and replace the disk on its
rabbet.

5. Place the paper on the wood, inclosing the bone, and then holding
the instrument up to the light, bring the needle-hole exactly opposite to
that in the bone, and ascertain with a lens that this is correctly done.

6. Smooth the paper on the wood, and before putting aside to dry again
ascertain that the centres are correct.

7. In about two hours remove the middle of the paper at the ring with
a sharp-pointed penknife. Take out the bone disk, replace the pin, and
trim the edge of the paper so neatly that the centre-piece may fall easily
in its place.

Tuomas E. Amyor, Diss, Norfolk.

( 244 )

PROCEEDINGS OF SOCIETIES.

MicroscoricaL Society, December 26, 1855.

Dr. Carpenter, President, in the chair.
H. Griesbach, Esq. ; —. Pillischer, Esq. ; F’. Haes, Esq. ; and Dr,
Stevens, were balloted for, and duly elected.
A list of persons proposed as Officers and Council for the year
ensuing was read, and ordered to be suspended in the Meeting-room,
Dr. Lankester read three papers, printed in the Journal.
Dr. Beale exhibited and described a new form of Microscope.

January 30, 1856.
Dr. Carpenter, President, in the chair.

J. Slade, Esq.; Dr. W. Rawlins; J. S. Gaskoines, Esq.; C. W.
Quin, Esq.; C. A. Long, Esq. ; and H. Sidden, Esq., were balloted
for, and duly elected.

Certain proposed additions and alterations in the Laws of the
Society were read, and ordered to be suspended in the Meeting-
room.

Feb. 27, 1856.
ANNIVERSARY MEETING.
Dr. Carpenter, President, in the chair.

A report from the Council and from the Auditors of the
Treasurer’s accounts was read, and ordered to be received and
approved.

The alterations and additions in the Laws, proposed at the last
Meeting, were read and adopted.

The President then delivered an address.

Dr. Lister; H. Morris, Esq.; Chas. Rivaz, Esq.; and C. W.
Gregory, Esq., were balloted for, and duly elected (see Transactions,
p. 15).

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JOURNAL OF MICROSCOPICAL SCIENCE.

EXPLANATION OF PLATE X.

Illustrating Mr. Huxley’s paper on Appendicularia.
Fig.
1.—Appendicularia flagellum seen from the side to which the caudal
appendage is attached, 7. e. the dorsal or hamal side.
2.—Body of Appendicularia, magnified ; side view.
3.—Body of Appendicularia, magnified ; dorsal view.
4,—Caudal appendage; showing the great nerve, with its ganglionic
enlargements.
A, Body. B, appendage.
a, oral aperture.
b, pharynx, giving off its lateral canals.
c, external opening of these canals.
d, ciliated circular bands, corresponding with the stigmata of the

branchial sac in ordinary Ascidians ; but here forming part of
the wall of the canal 8, c.

e, anus.

J, rectum,

g, cesophageal narrowing of pharynx.

h, right lobe of stomach.

z, left lobe.

k, testis.

1, axis of caudal appendage.

m, rounded granular masses projecting from the hemal wall of the
pharynx, and of doubtful nature.

n, Endostyle; here, as elsewhere in the Ascidians, the optical expres-
sion of the thickened bottom of a groove or fold, continuous at
its edges with the epipharyngeal bands.

0, one end of the heart.

», ganglion.

q, Ciliated sac.

7, otolithic sac,

s, nerve trunk.

t, ganglionic enlargements upon its caudal portion.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE XI.

Illustrating Mr. Currey’s paper on the Reproductive Organs
of Fungi,

Fig.

1.—A stellate spore of Stilbospora militaris, magnified 500 diameters.

2,—An abnormal spore of the same, magnified 350 diameters. Two of
the horns have failed to grow.

3.—The apex of a filament and fascicle of spores of Stilbospora militaris,
magnified 500 diameters.

4.—The apex of another filament and fascicle, magnified 350 diameters.

5.—A vertical section of a pulvinulus of Stilbospora militaris, magnified
60 diameters.

6.—Conidia of Stilbospora militaris, magnified 500 diameters,

7.—A fascicle of Stilbospora militaris, throwing out a germ-filament.
Magnified 350 diameters.

8 and 9.—Asci and sporidia of the Spheria accompanying Steganosporium
cellulosum. It is probably Spheria amblyospora. Magnified 220
diameters.

The ascus, fig. 9, is in an earlier stage than fig. 8, the sporidia
being of a paler colour, and the gelatinous envelope not
developed.

10 to 15.—Varieties of sporidia of Steganosporium cellulosum, magnified
220 diameters.

16 and 17.—Empty asci borne upon the stratum proliferum of Stegano-
sporium cellulosum. The internal second membrane is very
visible. Magnified 220 diameters.

18 and 19.—Bodies also borne upon the stratum proliferum of the Stegano-
sporitum. ‘The endochrome is divided into eight portions, being
apparently imperfect sporidia. Magnified 220 diameters.

20 and 21.—Ripe sporidia of Sphcerta amblyospora, magnified 220 dia-
meters.

22, 23, and 24.—Spores of Steganosporiwm cellulosum at the commence-
ment of germination. Attached to one of the germ-filaments is
a globular vesicle, possibly adventitious. Magnified 220 dia-

: meters.

25.—A sporidium of Steganosporiwm cellulosum after about three days’

germination. Magnified 220 diameters.

26.—An ascus and sporidia of Spheria cryptosporit, magnified 220 dia-
meters.

27 and 28.—Stylospores or perhaps imperfect asci of the same Spheria,
magnified 220 diameters.

29, 30, and 831—Abnormal asci of Spheria eryptosporii. The contents
are granular, but there is no symptom of the formation of sporidia,
Magnified 220 diameters.

32 and 33.—Curious instances of dehiscence of the asci of Spheeria her-
barwm. In fig. 32 the second membrane is clearly visible at both
ends of the broken ascus. In fig. 33 the second membrane is
reduced to a string, and encloses a single sporidium. Magnified
220 diameters.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE XII.

Figures of Camphor-crystal, illustrative of the observations of Messrs.
Spencer and Glaisher.

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JOUBNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE XIII,

Illustrating Dr. John Charles Hall’s paper on an Easy Method of
viewing certain of the Diatomacee.
Fig.
1.—Pleurosigma angulatum ; colour pale chesnut: striae 52 in 001";
length *0066" to -0100"; this figure is intended to give a general
view of the appearance it presents when viewed with this peculiar
illumination, and magnified about 800 diameters.

2.*—The same magnified about 2,000 diameters.

3.—Pleurosigma Hippocampus ; colour pale brown : long striz 32 in *001";
transverse striz 40 in *001"; length *0050 to 0066"; magnified
800 diameters.

4,—The same magnified 1,200 diameters, showing both the transverse and
longitudinal striz : a portion is also seen in dots.

d.—Pleurosigma Formosum; colour light chesnut-brown; strie 36 in
°OOL"; length °0141 to -0178".

* Since the present paper was in type, I have seen the very interesting book of
Dr. Carpenter “ On the Microscope :”’ in it, at page 307, will be found an engraving,
from a photograph of Mr. Wenham, of the Pleurosigma angulatum, as seen under a
power of 15,000 diameters. On comparing this with fig. 2, in the present plate, the
correctness of Mr, Fleming’s delineation will at once be apparent. Dr. Carpenter,
after having examined the valve with an objective having an angular aperture of 130°,
and very oblique rays, states that its hexagonal areolation becomes very distinct ;” he
states also, ‘* that when the object is accurately in focus, the hexagonal arex are seen
to be light, and the intervening spaces dark,” the reverse being the case when out of
focus ; this, of course, does not in any way affect the question, as to the nature of
these markings. I consider fig. 2, in the present plate, to be in focus.—J. C. H.

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( 245 )

ORIGINAL COMMUNICATIONS.

Notes on the SrructureE of Oscitiatori&, with a Description

of a New Spreciss, possessing a most remarkable Locomotive
Power, not Cra. By Dr. F. DALquen. (Plate XIV.)

Tue study of the structure of the Oscillatorie is particularly
interesting, from the fact that we may not unreasonably expect
to find in it a key to the singular motion from which they
have received their generic name, and which now, for more
than a century,* has formed an object of curiosity and interest
to the microscopist without having received as yet a satis-
factory explanation. In one species at least, I think, I have
been able to make out the leading features of its structure
and the mechanism of its locomotion. ‘The description of
this, to me, new species I wish to preface by a few observa-
tions, containing some new facts regarding the structure of
Oscillatoria in general, which may, perhaps, interest some of
your readers ; in doing so, it will, however, not be necessary
to refer to the general character of these interesting organisms,
as they must be familiarly known to every one who is in the
habit of using the microscope, and therefore I plunge at once
in medias res.

The following different tissues are observable in the true
Oscillatoria :—

1. An outer enclosing sheath ;
2. A special cell-membrane, with its contents ; and
3. The axis, or pith, of the filament ;

which we shall consider in the order here stated.

The filaments of certain species are enclosed in sheaths
(vagine) or continuous tubes, never showing any cross-
markings corresponding to the striae of the filament; they are
composed of a kind of cellulose, since, though they remain
unaffected by iodine, I have never been able to produce, on
subjecting them to the usual tests for cellulose, that peculiar
and striking blue colour characteristic of this substance. In
other species, these tubes are wanting, or have not yet been
observed. ‘They are easily recognized; when present, they
will be found projecting on one or both sides of the filament,
being considerably longer than the latter. Filaments enclosed
in their sheaths never, or but slightly, exhibit their peculiar
motions, though they may be seen sliding in them, back

* Their movements were first observed by Adanson in 1753
VOL. IV. PS)

246 ON THE STRUCTURE OF OSCILLATORLZA.

and forwards, or leaving them altogether; in the latter
instance, the filament, on sliding out, receives an impetus, as
it seems, from the sudden cessation of the impediment pre-
sented by the sheath to its forward motion. While sliding
within its sheath, I have repeatedly observed that the tapering
and bent extremity of the filament in its progress altered its
position with regard to the sides of the sheath, now pointing
upwards, now downwards ; performing, therefore, a kind of
rotation around its own axis in its progress.

The filaments themselves have been supposed to consist
wholly of protoplasm; this view is not correct, since the
protoplasm is enclosed in a proper cell-membrane, which has
not, to my knowledge, been noticed before. This cellulose
coat always shows the cross-markings corresponding to the
striae when such were observable in the filament, and which
divide it into distinct joints or cells; these cells, however,
seem to be what Kiitzing calls “ cellule hologonimice”
cells, completely filled out by the gonimic substance, or
endochrome, which circumstance causes the cells to resume
their former shape, after desiccation, on the addition of water,
and accounts for the difficulty of demonstrating their struc-
ture. They form, with the protoplasm deposited in them,
annular bands or concentric rings, around the solid axis of the
filament (formatio perigenata), A reference to Pl. XIV., fig 7,
will render its structure more intelligible. The presence of
this cell-membrane may be best demonstrated by breaking up
the filaments, either by moving the thin glass cover, or by
cutting through a mass of them in all directions with a pair
of fine dissecting knives. On now examining the slide, in
most instances many detached empty pieces of this cell-
membrane, with its stria, will be found, as well as filaments
partly deprived of the protoplasm, showing in those places the
empty, striated cellulose coat, figs. 1,2. On the subsequent
addition of iodine all these appearances will become unmis-
takeably evident; the entire portions of the filament turning
brown or red, while the empty, with its striae, remain either
unaffected, or at most present a slight yellowish tint, as is
frequently the case with cellulose when old, for instance. (PI.
XIV., figs. 3,8, 11.) Many specimens, however, do not readily
show the above appearances, but require some trouble and
management, while others do so readily enough; this arises
from the peculiar state they are in; as a general rule, I found
that those which admit of being easily broken up are the most
fit for demonstrating this cell-membrane. In case it might be
imagined I had mistaken the external enclosing sheath for the
cell-membrane, I will observe that I have repeatedly isolated

ON THE STRUCTURE OF OSCILLATORLA. 247

filaments plainly .enclosed in their sheaths, and have in-
variably been able to demonstrate the different tissues referred
to, viz., the plain unstriated cellulose sheath, and the striated
special or proper cell-membrane of the filament, deprived of
its protoplasm. Moreover, the sheaths never have any striae
corresponding to the joints of the filament, and I am rather
inclined to think that other observers, mistaking the cell-
membrane for the enclosing sheath, have been prevented from
earlier establishing the presence of the former, because I am
convinced, as it has been stated that the sheaths seldom show
any strie, that, where these striz were observed, the cell-
membrane has been mistaken for the sheath.

With regard to the contents of this cell-membrane, it has
already been stated that the protoplasm (or endochrome, since
it is coloured in the Oscillatori@) is deposited within it, in
the form of circular bands or rings, around the axis of the
cylindrical filament; they are evidently of a nitrogenous com-
position, coloured by chlorophyll; iodine turns them brown
or red, and syrup and dilute sulphuric acid produce a_beau-
tiful rose colour. The cells seem, however, not uniformly
filled with it, but its deposition is in some places less dense
than in others, as, for instance, in the centre. This circum-
stance, as well as that the cells are formed round the solid
axis of the filament, must be borne in mind on examining the
filaments while under the action of various chemical reagents.
By means of these latter, I think, it may be satisfactorily
proved that the filaments are really composed of separate
cells; syrup causes them to contract by exosmose, and, if it
is replaced by water, they resume their original shape by
endosmose (figs. 4, 5, 6). Another question, however, is, are
these cells in simple apposition without an intervening cedlu-
lose wall, or what kind of connexion, if any, exists between
them? This question is not easily answered, but I am almost
convinced that the strize of the cell-membrane represent
distinct joints, forming a cellulose wall, as represented in the
ideal section, fig. 7 b, because I have never observed the
endochrome recede beyond the striz on the addition of a
strong solution of chloride of calcium; and the lenticular
disks (fig. 9), or single joints, when on end, can bear any
pressure short of their entire destruction without displacement
of the endochrome, which would hardly be the case if it were
not enclosed within a proper cell. Further, in detached
empty pieces of the cell-membrane, some of the strie are
often seen out of their natural position, dividing the cells
obliquely, having been ruptured; and lastly, as there can be
hardly any doubt that the filaments consist of a series of

s 2

248 ON THE STRUCTURE OF OSCILLATORIZ.

cells, I think, from the presence of the proper cell-membrane,
it might be reasonably inferred that the septa likewise con-
sisted of cellulose, though difficult of positive demonstration
on account of their minute and delicate structure. On the
other hand, I must not omit to mention that I witnessed what
would lead one to think that a kind of immediate contact
existed between the cell contents; so soon as the points a and
b in fig. 8, which represents a part of a filament under the
action of iodine, began to recede from the cross-markings, the
opposite portions in the intermediate adjoining cells retracted
simultaneously, just as if a separation had taken place.

The axis of the filament may be compared to the pith or
medullary sheath (stratum medullare) of the Dicotyledons ; it
is solid, highly refractive; but slightly affected by iodine, and,
under a very high power, a granular appearance may be
distinctly seen in the very centre when the filaments are
broken up, and a single joint, which on end resembles a
lenticular disc, is examined. If the filaments are allowed to
dry spontaneously on a glass slide, a greenish thread may,
with a little care, be traced running through the middle of the
filament from one end to another. This is more decidedly
the case if the filaments have been previously treated by
iodine, fig. 10. While moist, no trace of this thread is to be
seen, owing to its being almost colourless, and rendered trans-
parent by the water; after desiccation, however, it acquires
colour by condensation or shrinking, and becomes visible ;
sometimes, also, it will be found protruding, and in other
instances I have seen it keeping up the connexion of cells,
otherwise separated, fig. 11. After the addition of a weak
syrup, | have also frequently observed an appearance which
seems to countenance the view I have taken, and is shown in
fig. 4.

With regard to their propagation nothing positive is known.
If kept for some time they gradually lose their green colour ;
those exposed to the sun much sooner, I think, than others
less exposed to its direct rays; the stratum eventually be-
coming brown, sinks to the bottom of the containing vessel ;
it presents a granular layer, embodying great numbers of
filaments in all stages of decay, and, what is very singular, a
ereat number of Amebe will be found feasting on them, with
swarms of lively Infusoria of the Monadina kind, briskly
flourishing their single flagelliform cilium about in all direc-
tions. I must also mention here a modification the filaments
are sometimes observed to undergo, which is represented in
figs. 12 and 13. Some of the cells, namely, contract in the
middle, and their colour becomes much deeper and more

ON THE STRUCTURE OF OSCILLATORIA. 249

brilliant; in other instances the cells assume more of a
globular shape, and in this case, the filament, which is usually
straight, deviates to the right or left after each globular ex-
pansion, and from both sides tapers down into it. I believe
the latter form is but a more mature state of the former; and
ultimately, at these joints, the filaments separate, setting the
globular cells free, which may, perhaps, justly be regarded as
gonidia. In other filaments the striz are formed; as it
seems, by a number of granules, though I believe they are in
reality to be found on each side of the cross-markings. As
these granules are only observable in some of the filaments,
and in others of the same species not, I think they denote a
peculiar stage of development, and [ am strongly impressed
with the notion that these bodies are in some way connected
with reproduction.

The growth of the Oscillatori@ has been stated by some to
be so rapid that they grow 10-12 times their length in as many
hours, and others have gone so far as to attribute their motions
to the rapidity of their growth. My observations have
taught me to regard these notions as entirely unfounded and
fanciful. Even Kutzing seems to share these extravagant
notions regarding their growth. He says (‘ Phycologia Germ.
p. 157, note): “All the Oscillatorie grow so fast that their
growth may be watched and followed up while under obsery-
ation with the microscope; this fact explains the pleno-
menon, that when they are slowly dried on paper in masses,
the filaments are prolonged in all directions, forming a ray
around the mass.” With all due regard for this distinguished
algologist, I think the fact cited admits of another, and what
seems to me the true explanation; the filaments, namely,
creep out from the mass, if I may apply this term to their
motions, wherever the presence of water facilitates their
movements ; in drying a mass of them on paper, the water
will naturally collect for some time at its circumference, and
allow the filaments to riggle out, forming thus the ray men-
tioned by Kiitzing. The formation of this ray is, therefore,
due to their protrusion, and not to a prolongation of the filaments
themselves, which alone is implied when speaking of their
growth. I have frequently observed, if a small portion of
the flaky stratum of Oscillatoria, of a deep, glossy greenish-
black colour, as found under damp walls, covering the damp
ground to the extent of several feet, be placed in a watch-
glass with water, in a short time nearly the whole extent of
the glass will be found covered with single filaments, forming
a kind of pellicle, and at first sight this might be taken for an
instance of their remarkable growth; but on examination, the

250 ON THE STRUCTURE OF OSCILLATORIZ.

small portion of stratum will be found almost completely
deserted, bare, deprived of its deep glossy colour, which
depended upon the presence of crowded masses of filaments,
which have forsaken their home and wandered forth under
the stimulus of the surrounding liquid element. Strange to
say, after about a fortnight the sides of the glass were less
crowded, the stratum having regained a little more colour,
and one could almost feel inclined to attach some truth to the
naive statement of the same observer, that the filaments leave
their sheaths to which they return when it is cold, &c. As
everything relating to their natural history is of some interest,
J will mention another observation I accidentally made.
Having emptied a bottle containing a stock of Oscillatoria,
and finding the sides of the bottle in several places covered
with them, I detached them from the sides, having previously
filled the bottle with water; the next morning I[ observed,
with some surprise, the rising bottom of the bottle covered
with a tolerably dense green stratum, but not a trace of any
of the detached pieces which I had left could be found; they
must, therefore, have crowded together, forming a little colony
of their own, being, as it seems, of a social disposition, and
gregarious in their habits.

The new species of Oscillatoria* which I shall now de-
scribe is peculiarly interesting, from its being apparently in a
state of transition, not having its cells filled out by chloro-
phyll, and thus admitting of a better observation of its in-
ternal structure; it was found forming an extensive, partly
frothy, stratum, of a dirty-green colour (drying blue-green or
zruginous), on stagnant water, and on being disturbed it sepa-
rated into small threads, having a twisted, curly appearance.
The average diameter of filaments is 1-6000"; diameter of
cells about the same; they are highly refractive, and the
most active | have as yet observed. I have stated they were
apparently in a transition state, because, besides those which
have their cells not coloured by chlorophyll, and which form
the great mass of them, there are others with only a few cells
filled out, appearing green; and again, others with all the
cells of the filaments filled up, and in this, what I suppose to
be their mature state, they resemble the usual forms the
Oscillatorie present, viz., filaments of a green colour, only
that in this instance the stria are very indistinctly developed.
In those with transparent, uncoloured cells the striz are well

* Though apparently-common, I have not been able to identify it with
any of the great number described by Kiitzing ; but as it may nevertheless
be known, | have refrained for the present from introducing it under a
specific name.

ON THE STRUCTURE OF OSCILLATORIA. 251

marked ; and through the middle of the filament runs a deep
green thread, somewhat tortuous like a swollen vein, perforat-
ing and connecting the cells from one end of the filament to
the other, forming its axis, and presenting an instance of a
contractile substance serving as an apparatus for locomotion
unexampled in the annals of vegetable physiology (figs, 14,
15). Their structure is, however, not so simple as one would
imagine from the description and drawings I have given ;
they present, on the contrary, so complicated and varying an
aspect, that it is next to impossible to give an adequate repre-
sentation of them, However, under a good object-glass
(1-8th), and at a certain focus, they appear as simple as
represented ; and I would add, it is only when seen thus that
their extraordinary motions, which differ in some respects
from those of other Oscillatorie, may be clearly observed.
The motions of the Oscillatorie are indeed so singular that
while some haye in vain attempted to explain them as partly
external and altogether physical, others are not wanting who
have come to the conclusion that they must be animalcula,
solely on the strength of their apparent voluntary movements.
Dr. Hassall, for instance, on the former supposition, says :
“The filaments are very straight and elastic, and when they
are placed for observation on the field of the microscope,
they are bent out of their natural straight line, and make an
effort to recover it ; currents almost imperceptible in the liquid
in which they are immersed, and perhaps unequal attractions,
are causes amply sufficient to explain their motions.”” The
most superficial examination, however, is sufficient to show
the futility of these arguments, and I would refer the reader
for a complete answer to them to a note of Captain Car-
michael, which will be found in Hooker’s ‘ Flora’ under
Oscillatoria ; and I will only add that a drop of Tincture of
Iodine, or an aqueous Tincture of Opium,* does neither
interfere with their efforts to recover their straight line, 7. e.,
with their elasticity, nor with the imperceptible currents of
the liquid in which they are immersed, but, nevertheless,
puts a stop to their motions. But, before referring further
to the cause of these motions, it will perhaps be desirable
to define strictly in what they consist. They are, generally,
not inaptly described as the oscillating of a balance with
an advance in a longitudinal direction; but | must mention
that sometimes these motions are slow, at others quick and
effected by jerks, but the motion itself consists in the
revolving of the filaments; they roll over and over, and
forward with a sudden start and then recoil, so that their
« Exposure to the vapours of chloroform produces the same effect,

252 ON THE STRUCTURE OF OSCILLATORIE,

forward motion is active and the recoil passive. To observe
this well, the very uppermost surface of the filaments ought
to be brought in focus, leaving the margins rather undefined,
bearing in mind that the filament is not a flat but a cylindrical
body. As to the cause of these motions, or the mechanism
by which they are effected, nothing positive is known; Dr.
Kingsley has observed the whole surface of a large species to
be covered with cilia, moving in a circular wave round the
axis of the filament. (Mic. Journal, No. xi. p. 243.) It
would be of the greatest interest to have this observation con-
firmed, as the presence of cilia would in a very great measure
explain their motions. As a further reason for such con-
firmation, | would assign the fact of having discovered, as I
believe, in the new species just described, a locomotive appa-
ratus within the filament, independent of cilia. While
attentively examining the green thread running through the
middle of the filament, it suddenly vanished in one cell, and
appeared more prominent in the next to it, repeatedly altering
its position in different cells, now vanishing, now appearing
again, without any other perceptible motion than a gentle
tremor of the filament. After more extended observation the
movement appeared to me to consist in a lateral deflection
and retraction of the thread. If the left hand, for instance, is
closed, and now the index-finger of the same hand is alter-
nately extended and bent, if the hand is not too plump, the
tendinous termination of the indicator muscle in its retraction
will be seen on the back of the hand to slip to the left side,
forming a curve, and to resume its former position on bending
the finger. This will give a very fair idea of what I saw at
that time. At last, however, having obtained a fresh supply
of this Oscillatoria, | observed, as I have since never failed to
do, in a filament of about six or eight joints, the most active
size, and therefore the most fit for observation, what I consider
to be its true motion. The thread suddenly began to spin
round, while the filament was set in active motion, passing
quickly out of the field with the corkscrew-like movement of
a very active vibrio. I have said, the thread suddenly
began to spin round—at least so it then appeared, though
further experiments have now convinced me, that the filament
itself revolves at the same time, as is the case with other
species of Oscillatoria—but its progressive motion only being
seen, the whirling movement seems to be confined to the
strongly-marked green axis or thread which divides the cells
longitudinally. ig confess, on making this last discovery, the
pleasure I felt on first beholding, what I could but regard as
the locomotive apparatus of the filament, was oreatly dimi-

ON THE STRUCTURE OF OSCILLATORLAE. 253

nished, since the question arises, is the spinning round of the
thread the primum mobile, the agency by which the motion of
the filament is effected, or is the motion of the latter due to
another cause, say for instance, ciliary action, in which latter
case the apparent motion of the axis or thread might be
accounted for by the revolving of the filament, which not
being distinctly observable would have the same effect as if
the thread alone spun round in propelling the filament. Still
after the most careful and patient observation, | must retain
my original opinion, viz., of the thread possessing independent
motion, and being the cause of the motion of the filament, for
the following reasons. I purposely watched and repeatedly
observed, while only the most gentle oscillations were observ-
able in the filament, the thread which was very distinct in
two adjoining cells, vanish out of one and not out of the other.
The gentle tremor of the filament could hardly be due to a
revolving of the filament; but even supposing it did revolve
at the time, as the thread in both cells was equally prominent ;
if its disappearance in one cell was owing to the revolving of
the filament, it ought also to have disappeared in the other cell
for the same reason. Similar appearances I have observed in
filaments which were partly bent, approaching the figure S,
and which could not have revolved around their axis without
its being plainly seen; yet, as in the former instance, the
thread could be seen altering its position in the different cells.
As a further reason for retaining my original opinion, I will
mention that by careful observation the body of the filament
itself may sometimes be seen to bend simultaneously while
the thread is seen to retract in the manner described above.
And, lastly, though using all the best means which have been
recommended by experienced observers, for the detection of
cilia, | have been unable to discover any ; and I would caution
other observers, in looking for them, not to mistake certain
appearances presented by the filaments under oblique light
and an object-glass of great angular aperture, which closely
resemble a fringe of cilia, though they are simply the result
of the highly refractive property of the filaments.

I have been thus particular in stating what I have seen, as
I am most anxious that other observers, with superior means
of investigation, whom I hope to induce to verify or correct
my own observations, should exactly know what I had seen;
and as I have provided myself with a good stock of this
interesting species, I shall be very happy to forward some of
it to those who feel interested, and inclined to investigate for
themselves what | consider to be a most important point in
vegetabie physiology, viz., the various motions observable in

254 ON THE STRUCTURE OF OSCILLATORIZ.

plants. On this head I would offer in conclusion a few
observations, in order to show that the present state of our
knowledge in this respect is far from satisfactory.

Almost every day brings forth a discovery by which the old
landmarks established in science for the arrangement and
classification of the various products of our planet are unset-
tled, and this is more particularly the case as regards those
two kingdoms, the lower forms of which approach so near one
another, that, for want of distinctive characters, we cannot
always draw a positive line of demarcation between them,
This state of uncertainty, though partly the natural result of
the very nature and conditions of the objects to which it refers,
still prevails to a greater extent than is warranted, and must
continue to do so until our present notions on this subject
have undergone a thorough revision. In my opinion, the
boundary assigned to the vegetable kingdom is too limited ;
our definition of a vegetable organism must be enlarged, and
we may vindicate for plants many attributes hitherto exclu-
sively attributed to animals, though, as a necessary conse-
quence of the more limited sphere of activity characteristic of
vegetable life in general, they will necessarily be manifested
in a less prominent manner; but this should not mislead us
so far as to ignore their existence altogether, and how vast a
difference in the manifestation of the various attributes of life
is observable even amongst animals themselves? A plant is
generally defined as a natural body possessing organization
and life, but devoid of sense and voluntary motion, Orga-
nization and life exclude all inorganic bodies; absence of
sense and voluntary motion the class of beings which are
comprised under the name of animals. Now a little consider-
ation will at once show us how arbitrary the limits are which
have been assigned to the vegetable kingdom in the latter
direction. By saying devoid of sense, is meant absence of
special organs of sensation, viz., nerves, and thus sensibility
is at once inseparably bound up with the existence of a
nervous system; sensibility, however, is simply the peculiar
aptitude or capacity of organized living beings for receiving
impressions, but not necessarily through nerves ony, neither
is it necessary that its effects should always be visible or ac-
companied by consciousness ; nerves presuppose sensibility,
but not, vice versa, sensibility nerves. Sensibility is something
prior to nerves; a faculty, an attribute of every living or-
ganism, but not every living organism must necessarily possess
nerves; nerves are only special organs characterizing the
manner of its manifestation in a certain class of beings. I
would remind tbe reader of the well-known instances of

ON THE STRUCTURE OF OSCILLATORLE. 255

animals which are devoid of a nervous system,. whether con-
sisting of a spinal cord or a system of ganglions. Thus, in some
of the Radiata, for instance, every trace of a nervous system has
disappeared, yet I am not aware that they are devoid of sen-
sibility, though without nerves. Nor would it avail much to
say, though we are not able to demonstrate its existence, yet it
may, nevertheless exist, as this argument would be equally
applicable in reference to plants. The existence of nerves as
special organs in certain classes of animals, must, therefore,
be regarded as an instance of that general law which may be
traced through the whole range of creation, aceording to which
the higher we ascend in the scale of created beings, the more
ample special and complex provisions are made for the mani-
festations of a more extended sphere of activity of individual
life; the greater its intensity the more special the apparatus
for its manifestations. ‘Thus the nervous system, the most
important of all, has reached in man the acme of its develop-
ment as a whole, while, as an instance of special endowment,
I may mention, that every hair of the beard of a cat is pro-
vided with its own separate nerve, having a special purpose to
fulfil in facilitating the carrying out of a powerful instinct
peculiar to this order of animals. The same relation obtains
with regard to other systems of the body ; compare, for in-
stance, the beautiful mechanism of the human hand with the
corresponding member of the monkey. To what a variety of
complicated and intricate operations is it not well adapted in
being provided with a number of muscles serving special
purposes? ‘Though the monkey can grasp a stick, he cannot
perform the act of pointing, the indicator muscle being absent.
What has been stated with regard to sensibility is not less
true as regards irritability. If taken in the sense of Haller,
as a property of the muscle, it becomes at once identified with
muscularity, and in this sense, of course, no one would think
of claiming it as an attribute possessed by plants; yet plants
undoubtedly possess irritability, and so do many animals,
which, as is admitted, are devoid of muscularity; no traces
of the fibrille of muscle exist in the animalcule and many
allied beings, yet nature has provided a substitute, viz., sar-
code, which may, for aught we know, perfectly supply the
place and functions assigned to nerves and muscles in the
higher animals. But we must go still further, and claim for
plants not only sensibility and irritability, but znstinct* also.

* Taken in the sense as applied to animals, which arbitrarily and
irresistibly impels them to the performance of certain actions always
directed towards a definite object, conformable to their nature, tending to
their well-being or propagation, yet without their being conscious thereof.

256 ON THE STRUCTURE OF OSCILLATORIZE,

If plants exist without these three general attributes of life,
then let me ask, in order to give but a few instances, why do
we witness in many plants a kind of sleep, or exhaustion and
subsequent recovery by rest? Why does the Mnothera
biennis open its flowers only towards evening, remaining open
during night, and fade the next morning if the sky is clear
and bright? Why, on the contrary, does the Drosera rotun-
difolia open its flowers only under the stimulus of the strong
light and warmth of mid-day? Why do the flowers of
Nymphea alba not only close but sink beneath the water
during the whole night, and rise only the next morning above
the surface? Why do the leaves of the Mimosa pudica, sensi-
tiva, and of a number of this class of plants, visibly contract
when touched? Why do the filaments of Berberis vulgaris, if
touched on the side next to the pistil, fly immediately towards
the stigma? Why do they lose this property if exposed for
a short time to the vapour of chloroform? Why, indeed,
does it return after a certain interval if the exposure has not
been too prolonged ?—(Mic. Journ., No. iii., p. 250.)

How exquisite must be the irritability of the Dionea musei-
pula, the leaf of which, or rather a part of it, folds up, even
if a little insect alight upon it? And why does it not relax
its grasp but when the little prisoner has ceased to make any
efforts for his delivery? Why do the five stamens of Par-
nassia palustris bend themselves forward and over the stigma,
and even, secundum ordinem, first one, after it has risen and
bent back, followed by a second, this by a third, and finally
by the remaining two at the same time ?

Many other instances of sensibility, irritability, and instinct
observable in plants might be adduced if needed, but surely
because these phenomena are witnessed only in a limited
number of plants, in so striking a manner, is no reason that
we should ignore them, neither can the visibility of their
effects decide the question of their existence, nor is it neces-
sary that all parts of plants should possess them in the same
degree. It has already been stated that there are animals
without a nervous system, without a head or distinct sexual
organs ; though, as a rule, the presence of a neryous system,
a head, &c., forms one of the most striking characters of an
animal, yet their absence, in some instances, does not eo ipso
exclude them from the animal kingdom. In the same manner
all parts of animals are not alike endowed with sensibility, as,
for instance, the epidermis and other epidermal structures,
as hairs, nails, Gc. The other negative qualification attributed
to a plant, viz., the absence of voluntary motion, appears to me
equally erroneous.

ON THE STRUCTURE OF OSCILLATORIA. 257

As a general rule, motion, no doubt, is one of the best
zoognomic characters, considering that the generality of plants
are fixed and rooted to the soil. The idea of locomotion, with
regard to land plants, would therefore involve an absurdity,
and the motions which have been observed in them, and of
which some striking instances have been mentioned, must be
necessarily confined to their several parts. Under altered
external conditions of vegetable existence, however, the case
is different. Amongst aquatic plants, those with roots stand,
of course, in the same category as land plants; others, without
roots, are kept floating on the surface of the water by the
construction of their leaves or other contrivances, as air-vessels
(aérocyste) for instance, such a provision being sufficient for
maintaining their individual existence intact. With regard to
those minute and beautiful objects, however, which are com-
prised under the general name Microscopic plants, quite
different relations obtain, and what in the former class of
plants must be regarded as a superfluity, we must here postu-
late as an indispensable requirement for their preservation,
nay, their very existence. Take, for instance, the Diatomacee
or Desmidiee. Light is as indispensable to them as to the
generality of plants, or as the air to us. This is an indis-
putable fact. Now, from their very minuteness, and the
nature of the locality where they dwell, they are every moment
exposed to be buried beneath the mud, and myriads are thus
buried by every risimg wave; they must inevitably perish if
not accidentally disentombed ; but a bountiful Nature has left
nothing to accident as regards the preservation of her offspring,
and even in this instance her own ample resources have not been
withheld, for she has provided them with an ingenious loco-
motive apparatus, which is to them what wings are to birds
—these, deprived of their wings, would certainly die of
hunger, setting aside that they would be left without the means
of escape from their natural enemies,—the others, without
their power of motion, would perish for want of the quick-
ening rays of light. Thus the presence of cilia, as organs
of locomotion, was recognised in several undoubted vegetable
organisms, which in their play had apparently so much of a
spontaneous character, that it became necessary to alter the
old formula, and y. Siebold stated that motion could only be
regarded as a proof of animality, if it consisted in, or was
accompanied by, voluntary contractions of the body. This
was done in order to exclude the moving spores of Alg@ from
the class of animals; but, more recently, other instances have
been brought forward which necessitate a further modification
of this formula, and the mistake of relying for our classifica-

258 ON THE STRUCTURE OF OSCILLATORIA.

tions upon a single character, as though life were not a mani-
festation of a complicity of forces and conditions, becomes
every day more manifest. If, on the contrary, the motions
allowed to plants be limited to physical motions, depending
upon external causes, which is the favourite doctrine of the
present day, then we have no alternative left but to hand over
to the zoologist many organisms, and the Oscillatorie amongst
them, which, in every other respect, are of undoubted vege-
table origin. Thus Mr. Hogg is in doubt whether the Diato-
mace are properly classed in the vegetable kingdom, because
they evince in their motions a controlling power independently
of a physical force, as intervals of rest and motion may be
clearly observed (Mic. Journ., No. xi., p. 235), and Captain
Carmichael (Hooker, |. c.) says, “I have bestowed consider-
able attention on such of the species of the Oscillatorie as fell
under my notice, and I do confess the result is something like
a conviction that they belong rather to the animal than to the
vegetable kingdom.” This view of the nature of the Oscilla-
torie might be supported by the fact that they evolve am-
monia when subjected to destructive distillation, and give off
carbonic acid gas in their living state as other animals. An
experiment made by me to that effect I twice repeated with
the same result, the particulars of which I will briefly state,
that it may be taken for quantum valeat. A quantity of the
frothy stratum of Oscillatoria was put in a hottle, nearly filled
with water, having its cork perforated by two glass tubes, one
a straight one, penetrating nearly to the bottom of the bottle,
the other a bent one, only perforating its cork, establishing a
communication with the air above the mass of Oscillatorie,
and another bottle, containing lime-water, on the principle of
a Wolfe’s apparatus. After six hours, the lime-water gave
clear proofs of carbonic acid gas having passed through it.

A third experiment made under the same conditions with a
mass of Confervee gave a negative result, and thus confirmed
the two former. Another circumstance worth mentioning is,
that the water in which they are kept is after some time ren-
dered slightly alcaline.* But to return to the previous ques-
tion: I would observe, that it might be shown, even if it be
granted that the motions of the Diatomacee are spontaneous,
that they cannot on that account alone be regarded as animals,
because no solid reason has as yet been brought forward why
we should not admit even spontaneous motions in plants; not
necessarily as proceeding from a consciousness or volition, but
as simple manifestations of instinct, blind impulses of their
vital force, yet withal independent of and unconnected with any

* At least in three instances this was the case.

ON THE STRUCTURE OF OSCILLATORI. 259

external physical force. Such inferences, I admit, are not
warranted by a superficial observation of external appearances,
but if we penetrate deeper into the idea of life, and look for
the cause of spontaneity and the proper sphere of activity of
every individual living being, we are forced to attribute to
every organism, possessing the general properties of life, an
animative principle (un principe animique), which is the cause
of the phenomena of life ; though this internal activity of a
being is not always immediately visible to the eye, still all
appearances, as expressions of its individual existence, prove
it to be so, and for that reason we must vindicate aléd for
plants a kind of soul,* however great the difference may be
which exists between it and the soul of an animal. Now, if
we must admit once that certain plants are endowed with the
power of motion, we must also admit that the determining
cause of such motions must reside or be sought for within
the plant itself; this would be conceding a kind of sponta-
neity, however limited its degree, agreeably to the narrow
sphere of activity characteristic of vegetable life.

This is not the place to enter more fully into these matters,
but I think I have said enough to bear out my assertion,
that the present state of our knowledge on these questions
is far from satisfactory, and I will "concltidle with refer-
ring to what, in my opinion, is calculated to retard in some
measure the progress of a sound vegetable physiology. I
mean the orthodox notions of certain eminent professors, and
with others a kind of fear of detracting from the dignity of the
genus homo, by being too liberal in acknowledging sundry
attributes in such inferior things as plants, &c. The latter
class we can pass by in silence, of the former we will give an
instance. If we descend the scale of creation we come at last
to a class of beings which are almost in a state of indifference,
that is to say, the prominent distinguishing features of each of
the two great classes of organized living beings disappear. y
Now to admit such a status indifferentia, as a common starting
point from which a progressive development in both directions

33

* Those of my readers who feel inclined to cry out ‘ riswm teneatis,
I would refer to men like Darwin, Treviranus, Carus, and other equally
distinguished men of science, who hold these opinions; see Dr. Ahrens,
‘ Cours de Psychologie.’

+ This is not only true as regards the two great classes of organized
beings, but in some respects also as regards the sub-classes of each ; thus,
to give but one instance: it is still a debateable question if the Lepidosiren
paradoxa, or Protopterus annectens, belong to the class of Fishes or to
that of Amphibia; it possesses gills and lungs, in addition to fish-scales.
Mr. Owen and Dr. Peters of Berlin contend for the former, Mr. Fitzinger
aud Professor Bischoff for the latter supposition.

260 ON THE STRUCTURE OF OSCILLATORIZ.

takes place, has been decried by some as being unphilosophical,
without, however, their offering us a better interpretation
of those facts which gave rise to the proposition. In the same
manner seemingly well authenticated observations, tending to
establish a transition from a vegetable to an animal existence,
and vice versd, have been met by a similar dictum ex cathedra,
which is deserving of censure, though coming from a vy. Sie-
bold or a Schleiden. Innumerable instances, from the insect
world alone, might be adduced involving metamorphosis not
less important as to the altered conditions of existence than
would be presupposed to take place in beings of the lowest
order, forming the boundaries of the two great classes, chang-
ing according to the varying external conditions from a vege-
table to an animal existence, and vice versd, and which might
have been set aside by a similar train of reasoning, were not
these phenomena from their nature capable of the most posi-
tive demonstration.

Note.

Since the foregoing was in print, further observations have
taught me, —

1. That the appearances of the new species of Oscilla-
toria, indicating a transition state, are produced by
the pressure of the thin glass cover when under
examination. And,

2. That the alkalinity of the water in which some Oseii-
latoria had been kept is traceable to the locality
from whence they came; the water being of the
most filthy description, communicating with a sewer,
and largely impregnated with putrid animal matter.

DENNIS, ON FOSSIL LIAS. 261

The existence of Mammirers anterior to the deposition of the
Lias, demonstrated from the Microscoric Srrucrure of a
Bone from the Rrver-Bep Deposit, Lymer Reers. By the
Rev. J. B. P. Dennis, Bury St. Edmunds. (Plate XVI.)

Turovenr the kindness of the President of the Geological
Society, a Paper of mine was read before the Society on the
19th of March last, in: which I brought under their notice
certain facts which seemed to me strongly to indicate the
existence of Mammifers at a period when the Lias had not
been deposited, and in a deposit well known by the name of
the Bristol bone-bed. Since then, through the kindness of
Professor Owen, Dr. J. E. Gray, and Professor Huxley, I have
had great opportunities of carrying on my investigations, and
I trust that, though errors may be found in my inductions, the
result of my inquiries will be found to have added some fresh
truth to the treasures of science.

Being desirous of giving publicity to some of the results of
my labours, the Editors of the Microscopic Journal have
courteously offered me an opportunity of so doing ; and as my
investigations have been for the most part microscopic, that
journal seems the most fitting medium for the introduction of
my views.

The microscope, like the telescope in another field, has
already revealed its wonders and unlocked many of the once-
hidden mysteries of Nature. No small authority has said,
“By the microscope the supposed monarch of the Saurian
tribes, the so-called Basilosaurus, has been deposed and re-
moved from the head of the reptilian to the bottom of the
mammiferous class. ‘The microscope has degraded the Sau-
rocephalus from the class of Reptiles to that of Fishes.” And
Mr. Quekett, adverting to these brilliant results of Professor
Owen, justly inquires, “ Why should not the minute fragments
of the other parts of the skeletons of extinct animals afford us,
by the same method of manipulation, some indications of the
particular class to which such fragments belong?” Such
reasoning is irresistible: and I may mention as a corrobora-
tive circumstance in favour of the use of the microscope, that
a geologist gave me what he considered, and what I believed
to be the bone of a pterodactyle, but which the microscope
proved to be crustacean,

la my examination of the microscopic structure of bone, I
haye observed certain facts that have induced me to suspect
a law which, if I am right in the discovery, will be of great
importance to science. I have noticed, for instance, in ani-

VOL, IV. . T

262 DENNIS, ON FOSSIL LIAS.

mals that have the power of springing, a preponderance of
pointed, oval lacune, and it is curious in this respect, to com-
pare the microscopic structure of the tiger’s femur with that
of the kangaroo, or the frog’s tibia with that of the newt.
The toad agrees very nearly with the frog, only the lacune
are longer, a character I have observed in animals that
climb. Those of the newt are quite dissimilar, and the struc-
ture of the tiger and the kangaroo is so very similar that it is
difficult at first to discriminate between them. The same
oval lacune are present in birds, and | cannot but think they
indicate a power possessed by the animal, of springing. The
ulna of the lesser flying opossum is a very beautiful illustra-
tion, the bone, in the shape of its lacunz, most resembling
that of birds, though still retaining sufficient evidence of the
mammal in its character. The pterodactyle, that singular
flying lizard, has the same pointed, oval lacune. ‘The bat,
also a flying quadruped, has the same; and it is curious to
observe in Mr. Quekett’s book that the only bird that has not
similar lacune is the parrot, a bird that never springs from its
perch, but climbs by its bill and claws. The force and
rapidity with which some birds rise from the ground, as the
partridge does, is perfectly surprising, and is quite as won-
derful as the spring of the tiger, the bound of the gazelle, or
the flight of the opossum: but the strain upon the bones of
these animals must be very great, and may well account for a
particular and suitable structure.

In the tarsus of a small Australian parrot, I find very few
of the pointed lacunz, but numerous long ones ; and in the
ulna of the same bird, the pomted ovals are much more nu-
merous. The Arctic fox, in its leg-bone, beautifully exhibits
the pointed oval lacune; so does the red Indian squirrel.
The same may be seen in the dog, cat, common fox, mouse,
&c.; and it would appear that they are present in all bones
that are subject to great or violent muscular action, as a
bird in its flight, or a mammal anda reptile in its bound. It
is curious also to compare the leg-bone of the ornithorynchus
with that of the turtle; for there is a very great similarity
between them, both in the haversian canals and the shape of
the lacunz ; and certainly that strange mammal does approach
in its habits the chelonian,

If a very thin vertical section is taken from the same part of
the humerus of a kangaroo and an otter, you will observe in
the former numerous narrow-pointed lacuna, similar to those
in the tibia of the frog or in the bones of birds; in the latter
you will not see one, the ovals seeming almost round. Com-
pare the otter with the beaver, another aquatic animal, and

DENNIS, ON FOSSIL LIAS. 263

again you see none of the structure of the kangaroo, but a
similarity in the shape of the lacune and the branching ap-
pearance of the canaliculi of the beaver to those of the otter ;
and compare both with the same bone of the newt, and though
the reptilian character of the latter is apparent, there is a
striking similarity in the appearance of the lacune. Exa-
mine a leg-bone of the ring-tailed monkey, and you will find
long lacune more abundant than the oval; the same will be
seen in the bear. These long lacune are very remarkable in
the radius of the chimpanzee, and would seem to be con-
nected with suspensive or pulling movements.

It is a step gained if it is found, upon comparison with the
bones of different animals who possess in common some
faculty, that the structure of their bones indicate it. The
next step will be to discover their points of difference as well
as their points of agreement with other animals. It may then
be possible not only to determine, for instance, whether the
animal could spring, but also whether it obtained its prey by
a spring, or by bounding escaped from the destroyer. All
this implies a thorough knowledge of the microscopic struc-
ture of the bones of animals from. observations made in diffe-
rent parts, and exact comparisons made with the same bones
in different animals; and until this has been done, no satisfac-
tory conclusion, in this respect, can be arrived at. If, how-
ever, there is any appearance of truth in this opinion, it is for
the mathematician to show what effect the difference of shape
in the lacune may have upon the strength and uses of any
particular bone. It may be only the sportive fancy of Nature,
as she has delighted to besport herself in the varied structure
of the foliage of plants; yet if that sportiveness has only
method and arrangement, it may prove of admirable use in
distinguishing animals by the microscopic structure of their
bones, as plants already have been by that of their leaves. In
the fragment of a bone, what clue can we have to the character
and habits of the animal to which it once belonged, unless the
microscopic structure indicates it. As far as I have been
enabled at present to carry my investigations, everything has
tended to show that there is a singular correspondence in the
microscope structure of animals of similar movements. This
matter, indeed, is well worthy of investigation, since if any
indication of habits may be deduced from the formal arrange-
ment of the lacunz, we shall be able to reconstruct. in some
degree, the history of a primeval animal, of which only a
fragment of its bone remains.

The presence or absence of haversian canals are no proof
for or against a bone being mammalian, as the radius of one of

Tt 2

264 DENNIS, ON FOSSIL LIAS.

our common bats does not exhibit* them, not to mention other
instances In the thick portion of fig. 2, Pl. XVI., there are
apparent traces of haversian canals which very probably have
been ground away in the more transparent portions of the
bone, a circumstance of frequent occurrence in grinding ver-
tical sections of fossil] bone. Figs. 2 and 2a show admirable
lacune that are in connection with an haversian system, and
very nearly compare with that of the walrus, fig. 8.

Having made these preliminary observations, we will turn
at once to the consideration of the fossil bone, of which fig. 1
is a representation, and attempt to determine its true rela-
tions. If by the microscope alone it may be shown to be
possible to assign it its due position in the scale of animated
beings, the achievement will be a brilliant one; if failure
ensues, at least it should be pardonable. Figs. 2 and 3 re-
present small vertical sections taken from the lower part, and
magnified 100 diameters. Figs. 2a, 26, portions of fig. 2,
magnified 400 diameters in fig. 25, the lacune are irregular,
and agree, in this respect, with some of the three-toed
sloth. The upper end of the bone is composed of fine can-
cellated structure: the appearance externally is very fine in
the grain like ivory. The bone came from the bone-bed
deposit west of Lyme Regis, which rests upon the upper beds
of the new red sandstone, and is identical with that deposit
which has been called—from, I believe, the circumstance of its
first having been observed at Bristol—the Bristol bone-bed.
It is principally composed of minute portions of bones and
fishes’ teeth, and was supposed chiefly to contain the remains
of fishes.

For convenience sake, I shall refer at first to Mr. Quekett’s
very excellent histological work ; and we have to deal therein
with Fishes, Reptiles, and Mammals, for Birds may well be
put out of the question. None of the plates on Fishes demand
our notice, until we arrive at Plate V., and this requires at-
tention. At once we may dismiss the Lepidosiren, as the size
and shape of its lacuna, not to mention other differences,
forbid us to compare our fossil with it; no more can the
Megalicthys Hibberti, figs. 1, 2, 8, 4, and 5, be compared with it.
We may also dismiss the figures of the Burdie house fossil,
for the lacune of that sauroid fish more nearly agree with
those of the pterodactyle. We have now only the supposed
Rhizodus to deal with, and a very slight examination of figs.
16 and 18, the transverse and vertical sections of the eranium
with the plate, will show at once that no agreement exists

* At least at present I have not detected any. They are hardly
apparent in the rib of the rat, and wanting in the scapula, &e. :

DENNIS, ON FOSSIL LIAS. 265

between them, either in size, shape, or number of the canali-
cule. Nor do we meet with better success in viewing the
plates on saurians: most of them much exceed the fossil in
the size of their lacuna, and those that do not, differ in form.
We are therefore obliged, so far as Mr. Quekett’s book is
concerned, to turn to his plates on Mammals, when at once
we cannot help noticing a striking similarity, especially when
we come to the sloth, and even more so when we reach
Plate XI., and find ourselves amongst the cetaceans. The
mammalian characters of the lacune and canaliculi of the
fossil in question, are certainly unquestionable; and besides
this, there is a very striking similarity in them to those of the
edentata and cetacea.

I shall now attempt the proof from my own practical obsery-
ations ; and let me here observe, that if any person wishes to
make himself acquainted with the structure of bone, the best
way is for him to do as I have done — grind for himself every
bone he can lay his hands on. It is a matter more of time
than of difficulty, except in the manipulation of fossil bone,
which requires all the care imaginable. Above all, let him
not put recent bone near Canada balsam, as all the minute
structure of bone is destroyed by it, unless polarised; and
even the canaliculi and lacune are filled with the balsam,
and often obliterated. Old or burnt Canada balsam should be
used when any is required, as is the case often in fossil bone,
when the canaliculi require to be better exhibited; and
as the small passages of fossil bone are generally filled up,
the balsam, of course, cannot then enter, while it has the
advantage of making other parts of the bone more trans-
parent. *

Some of the fossil fishes with which our bone was a con-
temporary were remarkable, some for the massive character of
the scales, and others the armature of their jaws. Through
the kindness of Mr. Adams,{ a gentleman residing at Buriton,
Petersfield, and who has in his cabinet some interesting
Stonesfield fossils, I have been enabled to examine the struc-
ture of the jaws of the Lepidotus and Pycnodus : the structure
of the former tubular, something like the fistularia; the latter
I have figured, as its lacune and canaliculi well illustrate the
icthic characters when they are present in fish, which are as
follows:—lacune of irregular shape, often stellate; canali-

* I have obtained the best sections by the aid of marine glue.

+ This gentleman has also enabled me to figure a fossil saurian from
Stonesfield, fig. 5; it compares almost exactly with the crocodile (vide
D and E of Plate), and is well worthy of notice from its showing that
nature has not deviated from her primeval plan.

266 DENNIS, ON FOSSIL LIAS.

culi few in number, rather thick at their bases, tapering off,
branched, straggling, reticulate.

I have examined other fossil fish, as the Dapedius and
others, but could find no appearance whatever of lacune or
canaliculi in their structure. One, a very powerful-boned
fish, that I found myself at Lyme Regis, and which I believe
is at present undescribed, is entirely destitute.

In the skull of the Pagrus, a recent sparoid fish, whose
jaws are armed with a most formidable array of canines and
molars, I have not been able to discover a vestige, either of a
lacuna or a canaliculus; and this 1 should presume applies to
all the class. The sturgeon only shows them in its fin-bones
and dermo-skeleton, where the lacune are very thick together.
Other large fish exhibited none. Our common roach has
them in the ribs. When, however, they are present, as in the
conger-eel, sturgeon, &c., they present precisely the same
characters, especially the very small number of canaliculi, and
their straggling, spider-like character. There is nothing
whatever to show that the bone under our consideration, as
the slightest examination of the figs. 21, 22, tells us, ever
belonged to a fish, for the lacunz and canaliculi have no
icthic characters. The contest, therefore, runs between
saurians and mammals; but I think I can satisfactorily show
that there are certain marked characteristics between the
lacunze and canaliculi of mammals and reptiles, and that in
these the fossil agrees with mammifers, though certain higher
saurians do approach the lower mammifers in apparent simi-
larity, as might be expected ; and much more iregularity of
structure is observable in the bone of the walrus or dugong
than we observe in the cat or giraffe.

There are certain well-marked and distinctive differences in
the lacune and canaliculi of Reptiles and Mammals; and
which, when made apparent, render the task easy in de-
termining the question about a fossil bone, if its structure is
sufficiently preserved so as to show some of the lacuna with
their canaliculi pretty perfect and well-defined.

The lacune in Reptiles are more generally irregular in
their shapes; and by this I do not mean that irregularity
which is observable in some mammifers, where the lacune
are some long, others oval, while some are nearly round ; for
a regularity is observed in one sense, as far as the individual
shape of a particular lacuna is concerned; but in the reptile
the lacuna is more often irregular in its shape. We must
be careful, however, not to confound a transverse or tan-
gential section of an haversian canal with a lacuna. The
crocodile, which of all reptiles that I) have observed, ap-

DENNIS, ON FOSSIL LIAS. 267

proaches nearer in the general appearance of its lacune to
mammals, haying its Jacune much more regular in form, is
still not free from the reptilian character. Great caution,
however, is required, as the walrus, and other lower mammals,
are inclined more or less to an irregularity in this respect.

The canaliculi of lizards are in general thicker than those
of mammals, and do not branch, but run in wavy courses from
the lacunz, where a number interlace. They have something
of the appearance of trellis-work. In the boa-constrictor the
saurian characters of the canaliculi are well displayed, which
more or less are apparent in all saurian bone that I have ex-
amined, The canaliculi also are much less numerous, though
their number varies in different Saurians. The definition,
therefore, of the general character of the lacunz and canaliculi
of Saurians will be :—lacunz more generally irregular-shaped
generally larger than mammals; the canaliculi generally larger,
in a similar manner extending from all parts, not so branched,
long, thick and wavy. There are apparent exceptions, of
course, to this general definition; but in the main it is truth-
ful and correct. The irregularity of the lacune in Reptiles
sometimes gives the appearance of branching; but then a
thinner part of the lacuna is mistaken for a canaliculus, I
have observed this in the boa-constrictor.

In examining mammal bone, the lacunz are observed gene-
rally to be (whether they are round, oval, or long and fusi-
form) of a pretty regular and uniform appearance, especially
in the higher mammifers, and are generally of an oval cha-
racter. They are also smaller than the generality of Saurians.

The canaliculi are much more numerous than those of
Saurians, and often fork out at their base ; and besides this,
give out branches. One end of a lacuna, when viewed with
its long axis, generally looks something like the head of a
stag’s-horn beetle, the canaliculi being bifid, and branched
like antlers. In most of the lacune of the crocodile, I have
observed the greatest apparent approach to this character ;
but it is more an apparent one (vide lacuna D). In the
mammal there is a considerable open space often left where
the extreme canaliculi bifurcate; whereas in the crocodile
they simply radiate all round, with little or no bifurcation, or
run out into a long point. The mammal definition will then
be :—lacunz generally of regular form, most frequently oval,
bifurcate, with forked, branching, fine and numerous canaliculi.

These remarks and definitions refer to vertical sections, and
the lacunz are defined as they appear when seen with their
long axis in the field. Transverse or tangential sections give
the lacunae always a more or less irregular form, and the+e-

268 DENNIS, ON FOSSIL LIAS.

cune generally are then presented with their short axis in
view. The mammal that shows most irregularity in its lacune,
as far as I have observed, is the walrus, and perhaps the
dugong. The definitions given appertain only to those
lacune that appear in the haversian interspaces. ‘Those that
form part of an haversian system have uniform and nearly
straight canaliculi proceeding from them, which in the
mammal generally are more numerous and finer, and less wavy
than in the Saurian.

The lacuna, fig. 4, is most remarkable for the great number
of canaliculi proceeding from it; and from a photograph that
I have of it, they appear so numerous, that they are not dis-
tinguishable one from the other. Figs. 2, 2a, beautifully exhibit
some of the lacune in the fossil connected with an bayersian
system, and very clearly show their mammal character.* They
bear a close comparison with the walrus ; and since that com-
parison is made with the recent bone of a mammal, it is easy
for any person who knows something about the microscopic
structure of bone, to form an opinion as to whether I am right
or wrong. For my own part, I cannot entertain a doubt upon
the question as to the bone belonging to some lower mammal.
But, at any rate, a new field is opened for the microscope ;
for the question I have raised must have a fair and scientific
solution. For if we are not able to discover the bones of
mammals and birds (and why we should not discover them I
know not, especially as the footmarks of the latter have been
already noticed), we shall at least be able to add new genera
and species to our existing list of reptiles and fishes.

The Bristol bone-bed is a mine of animal matter. Let only
the microscope, with its splendid powers, be scientifically
used, and it must bring to light new treasures for science. In
investigating these matters, one thing ought ever to be borne
in mind, and which I have already adverted to—the connec-
tion or relation that the bone bears to the animal to which it
belongs. If this is not considered, I think our inquiry is
almost useless. We want not only to say that such a frag-
ment of bone belongs to a mammal or a fish, but we also
desire to be able to discover something of the general cha-
racter of the animal to which it belonged.

In forming our judgment, then, concerning this or any
other fossil bone by its microscopic structure, we must do
pretty much what an anatomist would do under similar cir-

* | had intended that fig. 2@ and fig. 8 should have been magnified the
same number of diameters; the correspondence then would have been
more striking: but the reader must bear in mind that fig. 2 @ is magnified

twice as Many times as fig. 8,

DENNIS, ON FOSSIL LIAS. 269

cumstances, in determining about a particular bone or tooth ;
that is, try to discover the class and order of animals it most
resembles in its general characters. As I have adverted to be-
fore, great variety is observed in form and position of the lacunz
in the bones of animals; the canaliculi also vary. Having
first. of all determined the class, by a strict comparison with
known forms, then an attempt should be made to form a
judgment of the kind of animal, based upon inductive reason-
ing, the result of numerous and accumulated facts; and
unless we study recent bone with this end in view, we shall
only half do our work. It is a matter of difficulty, no doubt,
and the subject is quite a novel one; but it affords most
interesting material for microscopic inquiry.

Too great praise cannot be given to Mr. Tuffen West for
the extraordinary accuracy of his engraving. He says, and
truly says, that each lacuna, with each of its canaliculi, is a
study from nature, and though I see my name at the foot of
the Plate, yet I beg to say that all I have had to do with it
was in some measure to design its form, and to give Mr.
West the sections of bone to engrave from. I left them in
his hand to be produced in their truth and perfectness, and
most admirably he has accomplished the work. I ought to
mention that, for the sake of ready comparison, some fossil
and recent sections of bone have been introduced into the
Plate. They are as follows: A, single lacuna, with its
canaliculi, human; B, tiger's; C, boa constrictor’s; D,
crocodile’s; E, fossil saurian’s, Stonesfield; F, turtle’s, G,
conger-eel’s: these I term typical. Fig. 19, crocodile, trans-
verse section. Fig. 5, Stonesfield, fossil saurian. Fig. 9,
fossil vertebra of a whale. Fig. 7, fossil mammal, probably
a paleotherium; tertiary strata, Touraine. Fig. 20, toad.
Fig. 21, fin of sturgeon. Fig. 22, fossil fish, pycnodus,
Stonesfield. Fig. 10, fossil mammoth, Tull. Fig. 11, ant-
eater. Fig. 12, three-toed sloth. Fig. 15, ant-eater, vertical
section. Fig. 16, sloth, ditto. Fig. 13, dolphin, ditto. Fig.
14, dugong. Fig. 17, dolphin, vertical section. Fig. 18,
dugong, ditto. Figs. 1, 2, 2a, 26, 3, 4, and 6, representing
the fossil in question.

270 DR. LANKESTER, ON FUNGI IN WATER.

On the presence of Mtcroscoric Funer in WaTER deleterious
to Health. By Epvwin Lanxester, M.D., F.RS.

Nor one of the least important services rendered by the micro-
scope, is the facility with which the presence of organic matters,
especially when living, can be detected by its agency in posi-
tions where chemical analysis fails to recognise such compounds at
all. This is remarkably the case with the lower forms of animal
and vegetable life which inhabit fresh, mineral, and marine
waters. Some of the animals, as, for instance, the jelly-fishes,
which are large enough to be seen by the naked eye, and even
to present creatures of formidable dimensions, are scarcely
recognisable by chemical analysis in the water in which they
have existed. Such facts as these seem to indicate that the
microscope may be successfully employed in investigating waters
which may be suspected of containmg deleterious matters, or of
determining the presence of agents injurious to health. It is
true that our knowledge of the forms of microscopic life which
may be injurious to health is very limited, but sufficient is known
to stimulate further inquiry, and to prompt further efforts to
identify special organic forms with the unfitness of water for
dietetical purposes. On this ground I have thought the follow-
ing notes not unworthy of record.

In the autumn of 1854, I was requested to examine the well-
waters in the parish of St. James’s, Westminster, as some of
them, not without reason, as it subsequently turned out, had been
suspected of communicating, or predisposing those who took them
to, attacks of cholera. At the time I examined them (October,
1854) the majority of these waters presented no organic peculiari-
ties. One of them, however, that in Broad Street, Golden Square,
and which was afterwards proved to have been remarkably
connected with the great outbreak of cholera in the parish of St.
James’s, in September 1854, presented, after standing a little
time, a cloudiness visible to the naked eye. On examining a few
drops of this water with a } inch object glass, the cloudiness was
seen to be produced by the flocculent mycelium of a fungus
(Pl. XIV., fig. 16). On one occasion, whilst examining this myce-
lium, I observed a distinct passage of small oval bodies, of vary-
ing size, which passed on from one branch to another, and
presented an appearance closely resembling the movement of the
blood globules in the capillary vessels (fig. 17). ‘This movement
continued for several minutes. Although I looked for this move-
ment again several times, I was never able to observe it, and
the fungus shortly after this time was not developed in the water.

This fungus produced a sporidium (fig. 18), which was at
first filled with closely-packed spores ; after a little time they

DR. LANKESTER, ON FUNGI IN WATER. 271

exhibited a movement similar to that seen in the spore cases of
Achlya prolifera, and eventually burst the spore cases, and
became distributed by their movements through the water.

In a communication from Mr. Currie on this subject, he
says: “The circulation in the mycelium of Fungi would be a
novelty, but you are probably aware that there are many A/ge
in which moving bodies similar to those in your fig. 17 have
been observed, and it is a question whether these bodies
are the produce of the Alge themselves, or whether they are
the motile spores of aquatic Fungi which have forced their way
into the eells of the Alge.” The bodies moving in the my-
celium of the fungus were much smaller than the spores which
escaped from the spore-case.

Since the occurrence of the above my attention has been drawn
to the production of a fungus in well-water by Dr. Daubeny, of
Oxford. The well was situated at Cirencester, on the premises
of Mr. Robert Brown, wine-merchant. His son-in-law, Mr.
Pooley, who communicated the facts to Dr. Daubeny, lived on
the premises, and with his family was in the habit of using the
water for washing and drinking purposes. Mr. Pooley’s family
had suffered much from illness, and one child died. Mr.
Pooley says: “ My attention was first called to the question of
the water by Mr. Warner, who, from the rapid and fatal
symptoms in my little girl, and the occurrence of the same
symptoms in the rest on their return to the house, suggested
the possibility of the cause residing in the water.” The water,
although before suspected, from being ‘bright and imodorous,”
had not been regarded as the cause of the family illness. It

was now, however, again investigated, and Mr. Pooley states,
in a letter to Dr. Daubeny, that having a fortnight previously
filled an eight-gallon zinc cistern with the water, on going to
examine it he found “the surface covered to the thickness of
half an inch with a gelatinous opalescent cake.”

“The water was analyzed by Dr. Voelker, who found its chemical
constituents to be, in two imperial pints evaporated to dryness in water
bath, and residue dried in air bath at 300° F.

Grs.

Inorganic substances. : SP 35 ; 6°94

Organic matter . : . : : d 0°37
7°31 grains.

“Dr. Voelker considered, as far as it was chemically concerned, that the
water was a wholesome drinking water. I then submitted it to the
microscope, and Mr. Terry’s report is as follows :—

“¢ General Hospital, Bath,
“«« T have been able to discover no trace of sulphuretted hydrogen nor
ammonia in the water. The fresh water under the microscope gives

272 BRIGHTWELL, ON TRICERATIUM.

evidence of much vegetable growth (Fig. 19), and also a large number of
minute points, which, on the water being exposed to the action of the air
in a warm room, for three days, became exceedingly lively animalcules,
which move so rapidly over the field of the microscope that their exact
form cannot be defined, but appear to be of an oval, flattened shape, some-
what like the sole, and are not quite one-thousandth of an inch in length.’

‘* Professor Buckman’s microscopic observations exactly coincide with
the above, except that he has not found animalcules. His drawings are
similar. He says, the water contains an abundance of fungoid growths,
and from the fact of their requiring nitrogen for their nourishment, he
is of opinion they must obtain their supply from some communication
with a neighbouring cesspool. He concludes their presence is sufficient to
account for almost any amount of mischief.

“ Dr. Britten, of Bristol, observes, ‘1 find a few filamentous confervoid
filaments, with sporules and sporangiz developed upon and around empty
decomposing spore cases.”

‘“« My own observations, repeated a great many times, confirm the above,
with this addition, that besides the growths already mentioned, the great
bulk of the fungus is a prolongation of hair-like tubes, twisting and
decussating in every direction, so as to form a tangled knot, like a skein of
floss silk in a tangle.”

It is quite impossible to refer the loose floceuli (fig. 19)
found in this water to any particular species of Fungi. The
interest of the facts stated above consist in their probably indi-
cating a condition of the well-water injurious to health.

With regard to Professor Buckman’s theory that the well at
Cirencester probably communicated with a cesspool, I may add,
that the well in Broad Street, in which the fungus first described
was found, was subsequently proved to have communicated, by
a broken drain, with a cesspool in a neighbouring house.

Further Osservations on the Genus TriceraTium, with De-

scriptions and Figures of New Species. By T. Bricutwe tt,
F.LS.

In June, 1853, I communicated to this Journal a paper on
the genus Triceratium, with descriptions and figures of 22
species. Since that time, [ have used my best endeavours to
add to my knowledge of these singular forms, and have nearly
doubled my list. Those not before described I purpose
to describe in this paper, adding figures of each species,
and shortly to notice such as other labourers in the same field
have made known. [I take this opportunity, also, to correct
some errors in my former paper,

The species described and named by me T. brachiolatum I
conclude (since I have seen Ehrenberg’s fig. in his ‘ Micro-
geologie’) to be his TZ. pileolus. See ‘ Microgeologie,’ Pl.
XXXV. A. XXI. fig. 17.

BRIGHTWELL, ON TRICERATIUM. 273

Mr. Shadbolt’s 7. areuatum (See ‘Trans. Mic. Soc., Vol.
IL. p. 15, Pl. L., fig. 5”) comes also very near the same species,
if it be not identical with it.

T. comtum? Ehbr.—This species has recently been added
to the British Fauna, by Mr. Roper. See ‘Mic. Journal,’
Vol. II. p. 281. I have in my paper erroneously referred to
Kiitzing’s species Algarum for this species ; but the only notice
I find of it is in the last edition of Pritchard’s ‘ Infusoria,’
where a description is given, I presume from Ehrenberg, but
it is marked doubtful, and I perceive by Professor Smith’s
recently published 2 vol. ‘ Brit. Diatom.,’ he is not satisfied
that it is distinct from favus.

T. favus.—I have lately received a small gathering from
Sierra Leone, abounding in this species; and among the
frustules I have detected two of a cubical or square form, of
which | have given a figure. This variety is of great interest,
as confirming those discovered in two other species of Trice-
ratia, described and figured in my former paper. These
varieties, and the singular and bizarre forms into which
another species hereafter mentioned runs, show a tendency in
the frustules of this genus to vary from the regular form.

In a letter I have received from Professor Bailey, he says,
that although he leans to my opinion that these 4 and 5-sided
forms may be varieties of the triangular ones, he is not yet
fully convinced that this is the case. TJ. favus is, he says,
abundant on their coast, and he has seen it by thousands at
least, yet not one 4-sided or 5-sided one occurs; while in
South America, where the same: species is equally abundant,
a species with 4 sides, which he refers to Amphutetras for the
present, occurs with 7. favus, and resembles it closely in its
markings. The 4-sided forms having now- been met with in
connection with three distinct species, will, we think, go far
to establish them as varieties. The projection of a con-
necting membrane beyond the suture of the valve, which is
one of the characters of the genus Amphitetras, is not seen in
these square forms.

The fine species discovered by me, and which in my former
paper is described as T. striolatum, Ehr., appears to be new ;
and my T. membranaceum to be T. striolatum, Ely. See Mr.
Roper’s paper ‘ Mic. Journal,’ Vol. II. p. 8, Pl. VL, fig. 3.
Mr. Roper’s description and figure of T. striolatum, Ebr.,
will be found to agree with my 7. membranaceum, so as to
leave no doubt of their being the same. The species described
by me in my former paper as J. striolatum, I propose now to
call T. formosum, a name peculiarly applicable to the fine
frustules of this large and beautiful species.

274 BRIGHTWELL, ON TRICERATIUM.

Synopsis of new Species.
Section I, Sides concave, with angles protruded. Valvular
eile minute.

1. 7. exiguum, Smith ; Smith’s ‘ Brit. Diat.,’ vol. ii., p. 87, No. 17.—
This very minute species, the only one hitherto found in fresh water, has
been long known to the microscopists of this neighbourhood. It occurs in
fresh water at Ormesby and Horning, in this county, where it is not
uncommon.

Plate XVIL., fig. 1 a, b, c, end views ; d, front view.

2. T. brachiatum, n. s.—Angles drawn out into short thick arms,
bluntly truncated, and separated from the body by a distinct transverse
canaliculum.

Barbadoes earth. Plate XVIL., fig. 3 a, b, c, showing variations in size
and breadth of arms,

3. T. truncatum, n. s.—Like the last; but larger and stouter, and
having the surface of the frustule separated into twelve or more divisions,
by distinct lines or canaliculi, running horizontally from an irregular
central line, or canaliculum.

Barbadoes earth. Plate XVIL., fig. 4.

4, T. venosum, n. s.—Larger than the last. Sides concave, ends rounded
off. Canaliculi numerous, emanating from a central point in the frustule,
and diverging into two rows of irregular divisions on each side. ~

Barbadoes earth. Plate XVII., fig. 5.

5. T. coniferum, nu. s.—Sides of the frustule irregularly concave; the
angles being drawn out into an extended cone, recurved towards the end,
with a short stout horn near each end. Centre of the frustule convex,
with three stout sete ; one placed towards each angle.

Shell cleanings ? Plate XVIL., fig. 6a, end view; 60, front view.

Section IJ. Sides straight, or somewhat convex. Valvular
cells, varying in size.
6. T. favus, var. 8.—Cubical, four-sided, the sides somewhat concave,

and each of the four ends terminated with a stout horn.
Sierra Leone ; mouth of River Rohelle. Plate XVIL., fig. 7.

7. T. formosum, var.

Bermuda earth. Plate <WE fig. 8.

I deem this to be the same variety as that found with the recent frus-
tules. The occurrence of such a form in a fossil or deposit state, has in-
duced me to give a figure of it.

8. T. armatum, Roper. ‘Mic. Journal,’ vol. ii., p. 283, fig. 1.—I possess
several forms from different localities, nearly allied to, or perhaps, varieties
only of this species. The figure in the ‘ Mic. Journal’ being unsatisfac-
tory, I have given front and end views of British specimens.

Neyland, near Haverfordwest. Plate XVIL., fig. 9a, end view; 9 d, front
view.

9. Var. a.—Stout, and more convex than the British species; valve
studded with numerous short spines, horns short and stout.

Algerian deposit. Plate XVII., fig. 10.

10. Var. 8.—Smaller than the last; but like it in form, having three
spines on the surface of the valve, one on the middle of each side.

Australia, Plate XVIL., fig. 11, an end view; 110, front view square
variety.

BRIGHTWELL, ON TRICERATIUM. Pi,

11. Var. y. Frustule not only with numerous short spines, as in var. a,
but having numerous long and stout horns proceeding from the surface of
the valve.

This last has more the aspect of a distinct species ; and if so, I propose
to call it 7. horridum.

Algerian deposit? Plate XVII., fig. 12.

12. T. marginatum, n. s.—Frustule surrounded with a broad margin
or frame, having transverse canaliculi, and two large circular cells at each
angle. Surface of the margin with small circular cells, and of the centre
with small radiated cells.

Plate XVII., fig. 13.

13. T. radiatum, n. s.—Frustule large, surface undulated and de-
pressed in the centre, covered with minute puncta or cellules, arranged,
as in 7. condecorum, sides nearly straight, angles sharp, but without
cornua or horns. Short radiated lines proceed from the centre, outwards,
and from each of the sides inwards.

Barbadoes deposit. Plate XVIL., fig. 14.

14. 7. tabellarium, n. s.—Marcgin of the frustule thickly studded with
small cells, indented along the inner side in foliaceous curvatures ; surface
of the frustule spotted with small patches of cells. Angles with small

cornua or horns.
Honduras. Plate XVIL., fig. 15.

15. 7. hyalinum, n. s.—Small, transparent, surface with very minute
dots or cells, sides regular and straight, angles without spines.
Barbadoes. Plate XVIL., fig. 16.

Section III. Ends of the angles entirely rounded off.

16. T. Marylandicum, n. s.—Surface of the frustule covered with nu-
merous delicate finely-punctured parallel stris or lines, radiating from a
central pseudo nodule—a stout short spine placed laterally near each
angle, and in some frustules a spine also in the centre of each side ; sides
nearly straight, with the ends clean rounded off.

Maryland deposit ; P. Bailey.

Fragments of the frustules of this singular and beautiful species are
common in this deposit, but perfect ones are rare.

Plate XVIL., fig. 17.

17. T. punctatum, n. s.—Surface covered with large cell-like puncta,
suddenly diminishing in size at the rounded angles ; frustules somewhat
stout. ‘This species varies much in size, and in the stoutness of the
puncta,

Arctic Regions. Plate XVIL., figs. 18 a, 18 6, 18 ¢.

18. T. variable, n. s.—This species resembles 7. aléernans, but is larger,
and has-not only three lines, as in that species, but an indefinite and va-
riable number of other lines, upon the surface of the frustule. The angles
also are prone to run out into bizarre and ever-varying forms, giving a
grotesque appearance to the frustules.

Peruvian Guano, and in slides, from Mr. Topping, marked ‘“ Infusoria
Gomara.” Plate XVIL., figs. 19a, 19}, 19c.

19. T. parmula.—Minute, frustules thickly punctate; sides convex,
with small projecting papillaform angles, the outline of the frustule re-
sembling a little shield.

Port Natal, South Africa. Plate XVII., fig. 2.

20. T. orbiculatum. Shadbolt, see below, Pl. XVIL., fig. 20, a. 6,

276 BRIGHTWELL, ON TRICERATIUM.

New Species described by other Authors.

Mr. Shadbolt has described four new species from Port
Natal. See ‘Trans. Mic. Soc.’ Vol. II. p. 15.

1. T. sculptum. ‘Trans. Mic. Soc.,’ Plate I., fig. 4.—A fine specimen
of this singular species has occurred in a gathering received by me from
Wairau, New Zealand.

2. T. arcuatum. L.c., Plate I., fig. 5.—Qu. 7. pileorus, Ehr.? See
ante.

3. T. orbiculatum. lL. c., Plate L, fig. 6.—I have detected frustules
of what I take to be this species in shell cleanings ; and have seen slides
of the same from the Mauritius, marked 7’. ocellatwm ? Ehr.; but they by
no means agree with Ehrenberg’s specific character of that species—“* late-
ribus leviter concavis, cellulis inequalibus mediis maximis hexagonis.”
Mr. Shadbolt’s appears to me a good species, and appropriately named.
I have given a front and end view, to afford an opportunity of determin-
ing the species.

Plate XVIL., fig. 20 a, end view ; fig. 20, front view.

4. T. contortum. UL. c¢., Plate I., fig. 7, a, b.—This singular and in-
teresting species has some affinity to my 7. coniferum, but is quite dis-
tinct.

Professors Harvey and Bailey have described four new
species. See ‘Mic. Journal,’ Vol. III. p. 94. No figures are
given.

1. T. concavum. Hab. Tahiti.

2. T. gibbosum. Hab. Tahiti. :

3. T. orientale. Hab, Mindanao.—The description exactly agrees with
that of 7 grande, in my former Paper. See vol. i., p. 249; Plate 1V.
fig. 8. I conclude they are the same.

4, T. Wilkesii. Hab. Paget’s Sound.

Professor Bailey has also described and figured another
new species.

T. setigerwm. ‘ Smithsonian Contributions to Knowledge,’ Feb. 1854,
p. 11, fig. 24. Tampa Bay, Florida.—This species, Professor Bailey says,
appears to be allied to his 7. spinoswm, and both these species appear to
me allied to my 7. tridactylum, and to T. armatum, Roper. I incline
to think they are all one species, and in that case should be called
T. spinosum.

CONTRIBUTIONS TO MICRO-MINERALOGY. QE7

Conrrisutions To Micro-Mrneratocy. By Samvuen
Hieutety, F.GS., F.C.S., &e.

Parr 1.—Jnstruments of Micro- Mineralogical Research.

For the preliminary inquiry as to the general features of a
mineral mass, I arranged an instrument that should allow of
its free movement in all directions, and that might be left in
any position during a prolonged or interrupted examination
by means of the ordinary hand or pocket lens; this is deli-
neated in fig. 1, by which its construction will be readily
understood. To a firm base a ball-and-socket motion is
attached ; from the upper part of the ball arises a circular
stem on which fit three right-angled arms, capable of rotating
round their axis to any position, and then being clamped by a
broad circular stage that screws on to the axial stem ; through
the top of each arm a square rod passes, likewise capable of
being clamped at any point by little nuts; on the end of each
rotates a disc, studded with three pins, which may be used
naked or clothed with corks, according to the nature of the

body under examination: a telescopic universal movement-
stand for the lenses completes this arrangement. The stop-
VOL. IV. ; U

278 CONTRIBUTIONS TO MICRO-MINERALOGY.

plate of the lenses may be conveniently fitted with a small
moveable Tourmaline analizer. A stouter stand and stem,
carrying a Leeson’s or Schmidt’s goniometer, may be used in
place of the lens, for measuring the angles of large crystals.

Fig. 2.

As a Laboratory Microscope is subject to rough usage, an
economical form is certainly desirable ; the instrument, fig. 2,
I contrived to this end. It is of a good size, substantial and
neat-looking, has a rack-work movement to the body, bulls-
eye condenser, with universal movement, and packs into a
case 8 inches by 63 and 2? inches deep; the whole being
purchaseable under three pounds. When the drawer is in the
case, the instrument is upright. I have adopted a novel mode
of bringing it into the inclined position in the cheapest way,
by cutting the sides of the box away to a convenient angle, so
that, when the drawer is removed, half of the top of the box,
being hinged, falls to the incline, as shown in fig. 2.

For convenience in prosecuting the inquiries here laid
down, I deemed it necessary to construct an instrument that

CONTRIBUTIONS TO MICRO-MINERALOGY, 2t9

should be applicable, not merely to microscopical, but to
chemical and physical examinations, and that should combine
in one, the principles of Nachet’s Chemical Microscope with
those of Soleil’s Polaroscopes for the measurements of the
optic axes, circular polarization and saccharimetry, Darker’s
Selenite stage, Kobell’s Stauroscope, Leeson’s and Wollaston’s
goniometers, Jackson’s micrometer, with the means of deter-
mining the Indices of Refraction in minute crystals, Ke.
The instruments known as Nachet’s Chemical Microscope
since the Exhibition of 1851, and figured in the edition
of Professor Quekett’s Treatise of that year, has been
claimed by Professor J. Lawrence Smith, of the University
of Louisiana, U.S., as his invention, who seems wrath with
M. Nachet for not having mentioned his name in connection
with the instrument, and with Professor Quekett for not
knowing, what I believe few others knew till the appearance
of his article in the September number of Silliman’s Journal
for 1852, wherein he states that this form of instrument
he invented in 1850, and brought under the notice of the
Société de Biologie, of Paris, in the month of September of
that year, and with improvements in the micro-metrical parts
_ before the American Scientific Association in 1851. Those
who are acquainted with the wholesale way in which the MS.
descriptions of Exhibitors’ articles were, in most cases as a
matter of necessity, cut down to occupy the least possible
space in the Official Catalogue of the Great Exhibition, will
not, perhaps, think M. Nachet the one to blame that Pro-
fessor J. L. Smith’s name did not appear in connection
with the single line* that records the appearance of this Micro-
scope at the World’s Fair. Or can Professor Quekett be
fairly blamed, if with many calls upon his time, he does not
read every foreign journal that may issue from the prolific
Continental press, or that he did not become acquainted with
the proceedings of the American Scientific Association for
1851, before he issued his edition of December in that year,
considering that, like our own British Association, it does
not publish its Reports immediately after its adjournment; or
that he should not have known that Messrs. Wartz and Verdiel
had that form of instrument in use at their laboratory zn
Paris, especially as Professor Smith states that only mention
was made in the Minutes of the Societies referred to, and that
no published account of his principle had been given to the
world.

Curiously enough I first became acquainted with this prin-

* See Descriptive Catalogue, vol. iii., p. 1242, No. 1370; also Juries’

Reports, p. 267.
u 2

280 CONTRIBUTIONS TO MICRO-MINERALOGY.

ciple of Microscope in 1850 through Dr. Leeson, who,
during the summer months of that year, had his large Micro-
scope altered by Messrs. Smith and Beck to the form claimed
by Professor Smith, for the purpose of prosecuting, during the
winter months, some micro-crystallographical researches ; and

Fig. 3.

on lately referring to Messrs. Smith and Beck’s, their account-
books showed that the altered instrument had been delivered on
October 25th, 1850. On the same day that it was sent home, I
recollect that I went down to Greenwich with Dr. Leeson

CONTRIBUTIONS TO MICRO-MINERALOGY. 281

to try it, and it answered its purpose admirably ; thus two
persons were working out the same principle at the same
moment (as has frequently happened before in the records of
Science) quite independently of each other; and I think Dr.
Leeson* can as fairly claim this form of Microscope for
England as Professor J. L. Smith may for America.

The principle of introducing reflecting prisms into the
construction of the Microscope was, I believe, first employed
by Chevalier of Paris, who used a triangular prism in the
body, over his lenses, these being attached at right angles to
the body and pointed down to the stage ; here, however, the
prism was a more than useless intervention, the prism only
being justified (on account of loss of a small portion of light)
when the object-glass is to be placed under the object, as in
cases where vapours would arise, and thus dim or attack
lenses placed over them ; this specially obtains when chemical
solutions are to be examined, and where heat must be em-
ployed. If, however, Chevalier, by a modification of his
arrangement, used, as I believe he did (though I have never
seen his instrument), the lenses under the object, then THE
PRINCIPLE is due to him; the advantageous modification of the
angle at which the body is placed, and the resulting position
of the stage, to Professor Smith and Dr, Leeson; the econo-
mical adaptation of Soleil’s and other instruments, and the
general improvement in the arrangement and adjustments to
myself.

In the beginning of 1851 I sent a coloured drawing of the
instrument as I required it modified, and as represented in
fig. 3, to M. Nachet, who, however, from press of business,
could not get it made for me as quickly as [ wanted, and I
afterwards got it executed in this country; Kobell’s Stauro-
scope I have, of course, added since.

The instrument Professor Smith calls rue INvERTED Mr-
croscoPE, I, in its modified form and from its more general
application to crystallological researches, call THE MINERA-
LoaicaAL Microscopg, which I shall now proceed to describe.

The instrument’ is shown in fig. 3, as arranged for ordinary
structural observations, whilst in fig. 4 it is represented in
section, arranged for the optical characters of mineral bodies.

@he Base—on a central pivot, screwed into a solid circular
base, rotates a plate that carries the body, prism-box P, object-
glass and fine adjustment A ; to the side of the base is firmly
attached a square bar G, that carries the principal stage with

* Dr. Leeson has never described this, or laid any claim to the inven-
tion as yet.

282 CONTRIBUTIONS TO MICRO-MINERALOGY.

its coarse rackwork adjustment R, and the secondary stage, on
to which fits the diaphragm, polarizer, selenite plates, &c. A
tube screws into the top of the bar G, on which slides the mir-
ror. The object-glass and stages are centered, but the mirror
has free motion round the supporting-rod.

Fig. 4.

o

The Body slides into a socket attached to the prism-box at
the proper angle, so that its axis shall be perpendicular to the
outer face of the prism P. Within the draw-tube there are
fittings to receive glass tubes for examining with a Leeson’s
goniometer and minute-stop, the amount of rotation in liquids
that exhibit Cireular Polarization. If in place of the long body,
a tube of iron, round which copper wire has been wound, be
used, and the ends of the wires be connected with 12 or
more cells of a Groves or Maynooth battery, the rotation of a
polarized ray may be effected.

CONTRIBUTIONS TO MICRO-MINERALOGY. 285

A shorter body for other optical examinations replaces the
ordinary one; this is fitted with a Tourmaline T, a cell for a
plate of cale spar C, [cut at right angles to the principal axis
of the Rhombohedron or Hexagonal Prism,] when the instru-
ment is to be used as a modification of Professor Kobell’s Stau-
roscope for determining Crystal-Systems ; and two lenses L L,
with a Jackson’s Micrometer M, at the point of their foci, when
required for the determination of the optic axes on the principle
of Soleil’s Instrument.

The Prism P, is contained in a solid brass box, on the upper
surface of which is screwed the tubes that carry the object-glass ;
and one side is removable to allow of the prism being readily
taken out and cleaned.

The prism itself is six-sided, and has four polished faces with
angles of such dimensions, that a ray of light reflected down the
axis of the object-glass suffers two internal total reflections, the
second being axial to the body of the Microscope. ‘The angles
and quality of the glass are points of the greatest importance in
the construction of this instrument, as also are the proper adap-
tations of the object-glass and body to the line of reflection.

AnaLes. J. L. SMITH.
Upper obtuse = 145°.

acute — = bee
Lower obtuse = 1073°
5. acute; — 522-

The Fine Adjustment consists of a tube screwed into the
top of the prism-box at right angles to its surface ; over this,
tightly, but smoothly, slides another tube on which the object-
glasses are screwed. This is kept up to its work by a spring of
coiled wire, on which it rests; at right angles to its base an
arm projects, through which the fine-wormed screw of the
milled-head adjuster A works. The spindle of the adjuster A,
rotates in a socket projecting from the prism-box.

The Stage differs materially in its construction from that of
Professor Smith’s or Nachet’s, and allows a far wider scope for
pursuing the physical examination of mineral bodies. A stout
semi-circular arm works up and down the upright bar G, by
means of a rack and pinion R. This supports a circular stage
S, figs. 4 and 5; two axes at the circumference of the stage
pass through the extremities of the arm; the stage being
kept in a horizontal position by means of the nut x, which
passes through the arm into the stage; the nuts, N, screwing
on to the axes, clamp the stage firmly to the arm. The stage
has a projecting ring, within which a graduated plate rotates
when certain optical examinations have to be made, but which

284 CONTRIBUTIONS TO MICRO-MINERALOGY.

is ordinarily fitted with a plain metal_ plate that rises flush with
the top of the axes of the stage, or this may be replaced with
another plate, which rests on three screws, and has an arm pro-
jecting from one side, by which heat may be communicated to
the centre of the stage, when a spirit-lamp is placed under it ;
the three points of support not allowing the heat to be com-
municated to the other metal work. These three plates have
apertures in their centres, with screw rings, so that they may be
fitted with circles of thin glass, when liquids are used. Ifa
movement is required beyond that afforded by the object slides
having free play in all directions, a circular plate of metal or
glass, about ¢ inch less in diameter than the bottom plate of the
stage, with an inch aperture in the centre, may be used as sug-
gested by Professor Smith, motion being imparted by the ope-
rator’s fingers, or a Tilley’s, or any other form of mechanical
movement may be fitted within the ring of the stage. Of course,
in this instrument the object has to be placed with the thin
cover downwards.

By removing the nut N, the stage has free movement
on its axes, and may be inclined to any angle, as is shown in
fiz. 4, 8.8. One axe is longer than the other, and is so
arranged that the graduated circle before mentioned may rotate
on it, and be clamped, when desired, by the nut N. An index-

CONTRIBUTIONS TO MICRO-MINERALOGY. 285

point I, fig. 4, rises from the stage arm as the starting-point for
the readings. ‘Thus, in measuring the optic axes of a crystal,
the stage is inclined till one optic axe is properly cut by the
micrometic lines M, in the short body; the graduated circle
rotated till zero stands opposite the index-point I, and is there
clamped ; the stage is again inclined till the second axe cuts
the micrometic lines, and as the graduated circle has passed on
with the stage, the readings are taken from the fixed index-
point I. This circle is graduated from 1] to 180 on each half,
so that the reading may be taken on whichever side the stage
may be inclined. Its use as a Wollaston goniometer, and other
operations for which this is adapted, will be given under the
proper heads of these Conrripurions. The graduated circle
also fits over an eye-piece containing a double-image prism, and
thus constitutes a Leeson’s goniometer. The manipulation
and details of construction will be given under the head of
“Goniometry.” It will thus be seen that one graduated circle
economically does the work of three by this arrangement.

The Secondary Stage requires no special description, as the
ordinary accessory instruments are mounted sv as to slip ona
ring that rises from its surface. I find a reflecting bundle of
thin glass the best Polarizer for this form of Microscope ; by
removing the back and using the plain mirror, it may also be
used as a Refracting Polarizer. An electro-magnet arranged
so that its poles, which terminate in small sliding cones, may be
brought into the field of view without intercepting much of the
light reflected from the mirror, is mounted on a fitting, so that
when required it slips on the square bar G, between the princi-
pal and secondary stage.

It will be readily seen that this form of* microscope possesses
great advantages for chemical and mineralogical investigations,
as the stage is in a far better position for the eye to watch the
manipulations than in the ordinary instruments ; and the object-
glass being under the object cannot be dimmed or attacked by
the vapours arising from the liquids under examination. In
fact, Professor Bailey uses hydro-fluoric acid to determine
whether markings on a siliceous body are to be regarded as
elevations or depressions, as those parts that are elevated will
be last seen under the dissolving action of the acid. Professor
Riddell, in a note to Professor Smith, states, that after twelve
months’ trial he will not willingly return to the habitual use of
any known form of microscope, ‘‘ especially with high powers.”

Moreover, as the plate that carries the body and object-glass
rotates on the base, when the parts are properly centred, this
nay be used as a Demonstrating Microscope, as the body can

286 CONTRIBUTIONS TO MICRO-MINERALOGY.

be rotated to two persons on each side of the demonstrator
after he has arranged the object, and thus be examined by five
persons in succession. This has the advantage of economy over
Nachet’s three and four bodied microscopes (see vol. ii., page 72),
even if some of its other points are not attained.

Re-agent Botties.—In vol. il., page 58, of this Journal, my
friend Dr. Beale described and ficured a Re-agent Drop-
bottle used by him, and an improvement on its form by myself,
Finding that many persons meet with a “diff
culty in fillmg them by the plan there recom-
mended, though it isa very simple operation,
and moreover, that certain re-agents are
decomposed when they enter the heated
bottle, I have again improved its construe-
tion, which will be readily understood by
fig. 6. Instead of drawing out the neck of
the bottle to a capillary-tube, a piece of
thermometer-tube is drawn out to a fine
point, and is then ground into the neck of
the bottle like a stopper 5 ou the outside
of the neck a glass cap is ground in the same
way as in a spirit-lamp. When the bottle
has to be filled, the drop-tube stopper is
removed, aud firmly replaced after the bottle
is about two-thirds full, the warmth of the
hand affecting the contained air that rises to
the end of the bottle when the drop-tube is
pointed downwards on a slide, forces the liquor through the
thermometer-tube stopper drop by drop; and this is more
satisfactorily effected, as the bore is of one diameter along its
whole length, instead of bemg an elongated cone as in the old
form. ‘There should be a sufficient quantity of these in a
proper case ; such, with the other imstruments here described,
may be obtained of Messrs. Murray and Heath, opticians, of
43 Piccadilly. Watch-glasses, excavated and plain slides, stir-
rers, a Smee’s battery for electro-chemical decompositions, and
a Groves’ battery for examining the effects of electro-magnetic
currents on crystallization, &e., vill complete the micro- -mineralo-
gical laboratory, which may equal, if not rival, Wollaston’s
laboratory that was contained in a tea- tray.

Fig. 6

( 287 )

TRANSLATIONS.

Leuckart on the Microryie and Minute Structure of the
Eee-sHEtt zz Insects. (Miiller’s Archiv., 1855, p. 244.)

Tue Author, from observations made upon the ova of 180
insects belonging to the most various groups, is induced to
come to the following conclusions. As regards more espe-
cially the existence of a micropyle, he conceives that no
doubt can be entertained with respect to the following
points :

1. That this apparatus is characteristic of all insect
ova;

2. That it consists sometimes of a simple, sometimes
of a compound orifice, which passes through the tunics of
the ovum, and serves

3. For the admission of the spermatic filaments.

The last-noticed fact, it is true, has been demonstrated in
but a small number of species—not more than about a dozen
—but it may, nevertheless, perhaps be regarded as quite as
certain as the others. For the doctrine of impreguation,
however, this latter proof is of the highest importance, as by
it alone has the question respecting the micropyle of animal
ova received its pbysiological solution. Hitherto it might
always be doubted—as in fact it always has been—whether
the openings and canals which were some time since dis-
covered to exist in the envelopes of the ovarian ova in various
animals, and compared, as regards their external conditions,
with the micropyle of the vegetable ovum, also really pos-
sessed the physiological import of that micropyle. The
researches and statements of Keber cannot be regarded
having solved this question, since the spermatic corpuscle,
whose penetration and metamorphoses were so laboriously
described by that observer, is, as is well known, anything but
a spermatic corpuscle at all; ‘being only a thickening of the
vitelline membrane at the Facing of the micropyle process, and
to be found unaltered even after the escape of the embryo
(vide Bischoff, ‘ Widerlegung,’ and Hessling, ‘ Zeitscb. fiir
wissenschaft. Zool.’ vol. v. p. 892). The preceding observa-
tions, therefore (by Leuckart, in Miill. ‘ Archiv.’ 1855). to-
gether with those of Meissner, of which they are quite inde-
pendent, are the first, and, up to the present time, the only
ones demonstrating the penetration of the spermatic filaments

288 LEUCKART, ON MICROPYLE.

through a micropyle in the animal ovum. Meissner’s
researches noticed above, however, can, Leuckart says, be
taken into account in part, so far only as they apply to the
insect-ovuin. His statements respecting the ovum of Ascaris
and its micropyle, Leuckart is unable, as concerns the present
question, to regard as decisive, as he always found it impos-
sible to convince himself, in general, of the existence of a
vitelline membrane (Eihiille), nor, consequently, of a micro-
pyle, at the proper stage of dev elopment of those ova. Had
it even been proved that the conical discs regarded by
Meissner as the spermatic corpuscles, and which he states
penetrate into the vitellus through a micropyle, were really
the fertilizing elements, even in this case he is only prepared
to admit this much—that Meissner had shown in the
Ascarides the penetration of the spermatic corpuscles into
the, as yet, membraneless vitelline mass.

Previously to the observations of Meissner and Leuckart,
the known number of animals whose ova are furnished with a
micropyle apparatus was very small. Among these could be
reckoned with certainty only the Holothurie (Miiller,
Leuckart, and Leydig) and Ophiothrix fragilis among the
Echinoderms (J. Muller), Sternaspis thalassimoides among the
Worms (J. Miiller), Unio, Anodonta (Leuckart, Keber,
Bischoff, Hessling) and Venus decussata (Leydig) among the
Bivalves; All these animals have a simple micropyle, which,
according to Leuckart’s observations on the Waiade (Wagner's
‘Handw. d. Phys.’ Arr. Zeugung, p. 801) and Holothurie
(Bischoffs ‘ Widerlegung,’ p. 39), and which have since, in
all essential points, been confirmed on various sides, always
appears to be developed as a kind of stigma.

It might, consequently, almost have been concluded that
the micropyle, in general, existed only in those ova which, at
an earlier period of development, had been in continuous
connexion with the wall of the glandular follicle. The dis-
covery of the micropyle of the insect-ovum shows how hasty
such a conclusion would have been. We find a micropyle
in ova which are at all times free in their glandular follicles ;
it is clear, also, that this opening is formed in some other

way than by the dissolution of a previous connexion—that it
may arise in consequence of resorption. To this may be
added, that the micropyle apparatus of the insect-ova, ac-
cording to my researches, presents the most remarkable
diversities. in form and construction—such, in fact, as could
hardly have been previously imagined. Besides ova with a
simple micropyle, we are now acquainted with numerous
instances in which they are furnished with compound, and

? LEUCKART, ON MICROPYLE., 289

even with many such openings—with micropyles extending
over larger and smaller portions .of the whole vitelline
membrane,

These latter instances render it very probable that the
peculiar system of orifices and canals which, according to the
observations of J. Miiller (‘Monatsb. der Berlin. Akad,
1854, p. 164) and Remak (Miiller, ‘ Arch.’ 1854, p. 252),
pervades the chorion of our indigenous osseous fishes, also
belongs to the category of micropyle apparatus, and is sub-
servient to the act of impregnation. It is true that this
explanation of the import of these passages can only be satis-
factorily established by means of the microscope; but this
will perhaps remain a problem of difficult solution, as it can
scarcely be supposed that the spermatic filaments penetrate
through the solid chorion and make no use of the openings.
It is far more doubtful with respect to the radiating streaks in
the zona pellucida of the mammalian ovum, which are com-
pared by Remak with these orifices in the fish’s egg. It does
not even appear that these markings can properly be esteemed
as the optical expression of canals, seeing that neither dumina
nor orifices can be perceived in them. This much, however,
seems to have been made out, that the markings depend upon
a definite structural condition ; it must even be allowed that
the same conditions of structure may possibly indicate the
way followed by the spermatic filaments in their passage into
the ovum, and by which they penetrate the zona pellucida.
Eyen as canals, these passages would still require dilatation
in order to allow of the transit of the spermatic filaments,
which are found in the interior with their heads and tails.
In advyerting to these micropyle-like markings, J. Miiller
takes occasion to notice the radiating lines of the chorion in
the ova of Tenia. Leuckart has examined this in various
species (TJ. serrata, T. cenurus, &c.), and, from the optical
conditions presented, is satisfied that the markings depend
upon closely-placed perpendicular canals (1-2000"). But,
whether these canals penetrate the chorion completely, he
leaves undecided. And it must, of course, remain equally
doubtful whether they fulfil the function of a micropyle. At
the same time, he says that he does not believe such to be
their nature ; in the first place, because these canals in other
cestoid worms (Ligula, Tetrarhynchus), as well as in Tenia
cucumerina, &c., are wanting, and also, for the reason that
since, according to the anatomical conformation of the sexual
organs in these animals, impregnation takes place before the
formation of the chorion, any introduction by means of a
micropyle can scarcely be required.

290 LEUCKART, ON MICROPYLE.

In general, he is of opinion that we are by no means justi-
fied in assuming the existence of a micropyle-apparatus
universally in the animal ovum. That for the purpose of
impregnation, it is in all cases necessary that the spermatic
filaments should come into immediate contact with the vitellus,
can no longer admit of doubt, from tke result of recent ex-
periments, and particularly from the researches of Newport
(on the Frog’s egg), of Bischoff and himself (on the Frog’s and
mammalian ovum), of Meissner (on the mammalian oyum),
and of Lacaze Duthiers (on that of Dentalium), leaving out
of the question the observations on the eggs of Insects—but
this contact may probably be brought about in different
animals by different modes. In the same way that the
existence of an operculum, of valves, and similar provisions
for the liberation of the embryo from the coats of the ovum,
is limited only to certain species of animals; that is to say, is
governed by certain external conditions, although the em-
bryos, without exception, are liberated: so, also, is it pro-
bable that the existence of a micropyle for the admission of
the spermatic filaments is confined within certain bounds.
We are already in a position partly to determine, a@ priori, the
conditions under which the presence of a micropyle in the
animal ovum is rendered a physiological necessity. This
will be the case especially in those instances in which the
ova are very early, and before they come in contact with the
spermatic fluid, surrounded with a firm and resistant en-
velope, the penetration of which would resist all the boring
powers of the spermatic filaments. This would happen more
especially with ova furnished with a chorion (that is to say,
with a second, usually very firm envelope, formed in the
ovary), in which we may predicate the existence of a micro-
pyle. To this kind of ova belong, also, nearly all those cases
in which we have hitherto found micropyle-organs—the ova of
Insects and of osseous Fishes-——those of the Holothurie, and
also of the Bivalves.

It can scarcely, perhaps, be assumed that our observations
respecting the occurrence of the micropyle in the ova of
animals are at present conclusive. We shall undoubtedly
meet with such a provision in numerous other animal forms.
In most cases, we should certainly not place too high a value
upon the negative results of earlier observations. Personal
experience will show how easy it is to overlook an apparatus
of the kind, especially when it is confined to a limited spot,
and is otherwise indistinctly indicated; and it will be seen
that such a denial of its existence is unjustifiable. As
regards himself, Leuckart would remark that, notwithstanding

LEUCKART, ON MICROPYLE. 291

some experience in the detection of this apparatus, he has,
nevertheless, in many cases been compelled to make pro-
longed and often-repeated examination, and to devote the
closest attention to the subject, before satisfying himself with
respect to its existence and conformation. Had he not
entertained, a priori, the firmest conviction of its existence,
it would in many Insects certainly have escaped lim.

On the other hand, however, he says we must not expect
that the existence of a chorion is in all cases associated with
amicropyle. The chorion may possibly not be formed until
after the fertilizing contact with the spermatic filaments has
taken place, as in the Turbellaria, Trematoda, and probably
also in the Cestoidea, in which, to judge merely from the
anatomical conformation of the sexual organs, the spermatic
filaments are enclosed at the same time with the vitel/us and
the germinal vesicle, in a hard chorion-like capsule. Ac-
cording to Meissner, che ovum of Gammarus has a micropyle
only in the vitelline membrane, over which the chorion is
continued; in this case, impregnation, without doubt, takes
place also before the deposition of the chorion.

We have thus sought to refer the physiological necessity of
a micropyle at once to the physical condition of the egg-
membranes which are formed before impregnation has taken
place. But, at the same time, it can by no means be said
that such a provision is exclusively confined to ova furnished
with firm membranes. There remain numerous other con-
ditions which, even in the case of a soft and delicate covering
to the ovwm (Meissner expressly remarks of the vitelline
membrane in Gammarus, which has a micropyle, that it is
‘‘ excessively delicate”), render the existence of a micropy le,
if not absolutely necessary, still advantageous, But in any
case, the occurrence of the micropyle under these circum-
stances will, of course, be far more limited than in ova having
a hard and less penetrable covering.

Thus there may be said to be three distinct modes in
which impregnation, that is to say, the contact of the
spermatic filaments with the vitellus, is brought about :—

1. The entrance of the spermatic filaments, with
penetration of the egg-covering ;

2. Penetration through micropyles ; and

3. Penetration into the vitelline mass before the
deposition of the membranes of the ovum.

To which may be added a fourth mode of contact, lately
pointed out, more particularly by Meissner :—

292 LEUCKART, ON MICROPYLE.

4, Contact through premature dissolution of the vitel-
line membrane, as takes place, according to Meissner,
for instance, in the Earthworm. The Gasteropoda, also,
in which a similar condition has been long known (vide
Leydig. ‘ Zeitch. fiir wissenschaft. Zool. Bd.’ ii. p. 127),
might probably be here included, as well, perhaps, as the
Hirudinez and others of the Invertebrata.

What becomes of the spermatic filaments after they have
penetrated, and what particular part they may play in the
changes which we know immediately succeed the so-termed
impregnation, we are at present scarcely in a condition to
surmise. This much only is known with certainty—that the
spermatic filaments, some of which enter the vtel/us, whilst
some remain in immediate contiguity with it, between the
vitellus and its membrane, gradually dissolve (according to
Leuckart’s observations in Melophagus and Ephemera, far
more quickly than the filaments which remain external).
Whether this dissolution take place in consequence of a kind
of fatty metamorphosis, as Meissner states, or of a simple
disintegration and liquefaction, Leuckart is unwilling to de-
termine. It is sufficient to know that the filaments which
have entered are dissolved. But what farther becomes of
the remains of these fertilizing elements is at present wholly
unknown, It is highly probable that the substance of the
spermatic corpuscles, after their dissolution, becomes mixed
with the vitellus, but whether in a fluid or a molecular form
we. know not—not knowing, even, whether this commixture be
deferred until impregnation is completed, and is conse-
quently, to a certain extent, only adventitious and incidental,
or whether it afford an impulse of some kind essential to the
process of impregnation and development. Still less, there-
fore, are we in a condition to determine whether, in the latter
case, the remains, whatever they may be, of the spermatic
filaments directly participate in any way in the formation of
the embryonic cells, or, indeed, in the construction of the
embryo. The demonstration of an immediate contact between
the spermatic filaments and the vitellus is undoubtedly an
important and interesting fact in the history of impregnation,
but one which, it is to be feared, will not soon be brought
within the compass of our sensual perceptions.

(298)

REVIEWS.

TRANSACTIONS OF THE PATHOLOGICAL Society, Vol, VI.

Tue volume of the Transactions of the Pathological Society
for the present year has been punctually delivered to its
members. It possesses the high qualities which we have had
occasion to praise in its predecessors, and, to us, it has the
additional interest in being another example of the increased
appreciation of the microscope in the prosecution of patho-
logical investigations.

In the present volume the great majority of the illustrations
are of pathological histology, and there is scarcely a single
specimen referred to in which the microscopical appearances
are not recorded; this work, therefore, falls naturally enough
within our limits to review; and while, as we have already
said, there is much to admire, and much to praise, in these
published details of a year’s accumulated labeurs of the Pa-
thological Society, we think, in this Journal, we may very
properly point out and criticise those shortcomings and those
errors which here and there exist, and which in one or two
instances form unsightly blots on the pages of a beautiful
volume. We must, however, assure those whose productions
are unfavourably noticed, that they are criticised in no un-
friendly spirit, but rather to enforce a more scrupulous caution
for the future ; and, we believe, we may safely add, that sub-
sequent volumes of the Pathological Transactions will not
suffer by the adoption of our suggestions.

Among the list of contributors to the present volume we
find a goodly array of names, principally of young, earnest,
working men; and among the specimens exhibited are many
of rare interest.

Of the 161 original communications, and the 18 reports
on specimens by referees, we will select a few of the more
interesting ; we cannot, however, help expressing our regret,
that the reports of the referees bear so small a numerical pro-
portion to the original communications ; for we have always
considered that the plan adopted by the Pathological Society,
of referring all doubtful specimens and disputed points to the
scrutiny of a committee of two or more gentlemen, who have
paid particular attention to subjects similar to, or identical
with that in dispute, has constituted one of its best charac-
teristics, and has given peculiar weight and value to statements
which have emanated from its members. In the present

VOL. IV. xX

294 TRANSACTIONS OF THE PATHOLOGICAL SOCIETY.

volume we fear the officers of the Society have scarcely availed
themselves sufficiently of this wholesome surveillance of
referees.

Beginning with the diseases of the nervous system, with
which the present volume of the Transactions of the Patho-
logical Society commences, we observe an interesting account
of neuromatous tumours on the posterior tibial nerve, by Dr.
Van der Byl, the structure of which was investigated by
Dr. Snow Beck, who comes to the following conclusions,
based upon a careful microscopical scrutiny :—

“© 1, That neuroma originates in an individual fasciculus, and is confined
to the fasciculus in which it commences.

“2. That the adjoining fasciculi become altered by the pressure of the
tumour, but more especially by the constriction of the cellular tissue of
the neurilemma.

“3. That these tumours originate in a deposit within the membrane
surrounding the nervous tubules.

“4. That the individual tubules in the fasciculus become altered, from
the pressure of the deposit which has taken place amongst them.

“5, That this deposit becomes organized, subsequently grows, and
finally obliterates all appearance of the nervous structures amongst which
it originates.”

Among the “ Diseases of the Organs of Circulation,” we
find an account, by Dr. Wilks, of a very curious disease of the
heart, consisting of cysts adherent to the outer surface of the
organ, and composed principally of a fibrous tissue, displaying
great peculiarities of structure.

The walls of these cysts were composed of interlacing
fibres, many of which hung by free extremities into the cavities
of the cysts, and “to them are attached a number of earthy
bodies, of a round form, semi-transparent, yellowish, very
hard, and each of about the size of a pin’s head.” The fibres
themselves “‘ have a beaded, nodulated, or varicose form; that
is, they consist of a slender stalk, which swells out at intervals
into oval or rounded dilatations, and passing continuously
through them, without much variation of outline, appears as a
firm fibrous band.” These oval nodes on the fibres have a
central band passing through them, and appear like beads on
a string. Some of these nodules overlap each other, others
being widely separated; others again are faintly marked on
their surface by two concentric rings.

Of the real nature of this specimen, Dr. Wilks does not
venture to hazard an opinion, ‘The structure is certainly very
remarkable, and we do not remember that anything exactly
similar has been recorded.

Another interesting communication relative to a morbid
condition we have not previously described, also from the pen

TRANSACTIONS OF THE PATHOLOGICAL SOCIETY. 295

of Dr. Wilks, consists of an account of fatty degeneration of
the malpighian bodies of the kidney, all the other structures
of the gland, including the tubes, being free from that change.
The illustrations of this Paper, as well as the previous one,
are from original drawings by Dr. Wilks, and are very beau-
tiful ; but, in the one we are now considering, this usually ac-
curate observer has made a somewhat singular mistake in the
magnifying powers he has represented. The three figures
given in the Plate in question are said to represent different
portions of the gland, magnified respectively 6, 40, and 160
diameters. Now, between these numbers, there is a certain
proportion ; and we should expect to find the same proportion
in the structural elements, as represented in the several
figures; but here we are disappointed. The first figure is
said to represent “‘a small portion of the kidney, as viewed
with a simple lens. Magnified 6 diameters.” And this, from
the size of the opaque white malpighian bodies, is no doubt
pretty correct. The second figure of the same, ‘‘ magnified
40 diameters,”’ is also probably correct ; and the two have, as
they ought, about the proportion of 1 to 7. But in the third
figure, “‘ magnified 160 diameters,’ Dr. Wilks seems to have
lost sight of proportion altogether, for he has represented the
malpighian bodies in this figure, not four times the diameter
of the second, as we should have supposed, (40 x 4=160,) but
eight times. Supposing, however, that the two former figures
be correct, which we believe them to be, the third figure
should be defined as magnified 320 diameters.

Among the most interesting histological specimens in this
volume, are some examples of osteoids—in and among fibrous
tissues of various organs. Dr. Kirk gives two interesting ex-
amples of formations of bone in eyes damaged and rendered
useless by long previous disease; and the specimens have
been fairly described and illustrated. There are some points,
however, to which we must take exception. In the first
place, the description of the first figure, (PI. XIII., fig. 1,)
** showing the earthy matter exposited in the form of granules
in a fibrous stroma,” involves an idea which we believe is not
a true expression of the calcification-process. We would sug-
gest, as more probable, that these little spherules may be of
the same nature as those described by Dr. Hyde Salter in the
fifth volume of the Society’s Transactions, as occurring in an
osteoid in the pleura, consisting of minute isolated globules,
in which the earthy matter has impregnated the animal, like
the calcification-globules of dentine.

In fig. 1 a, we certainly have failed to see the “ crystalline ’
appearance described by Dr. Kirk; and we notice, moreover,

x 2

’

29G TRANSACTIONS OF THE PATHOLOGICAL SOCIETY.

between this figure and the preceding one a total dispropor-
tion of measurements—the latter figure being full ten times
less than the former, instead of five, according to the magni-
fying powers stated. The same disproportion, in figures 2
and 38, exists between the lacune magnified 250 diameters,
and those stated to be enlarged 50 times; the former are full
ten times larger than the latter. But the most remarkable
examples of confused and erroneous microscopical measure-
ments are to be found in observations by Drs. Jenner and
Hellier, on some osteoids from the lungs and omentum of a
patient who died from malignant disease of the femur after
fracture. The history of the case, which is very interesting
indeed in a general pathological sense, we shall not follow, as
it is foreign to our present object. On the description given
of the structure of the specimens, however, we have unfortu-
nately too much reason to comment; we ought rather to say,
of the total absence of description; for even under the head of
“* More minute examination of the morbid growths,” though a
subsequent paragraph is commenced—“ The growths in the
lungs,” Plate XV., figs. 1, 5,4,—which figures, by the way,
are intended to illustrate bone-lacunz—no account whatever
is given of anything osteoid, and no description certainly of
the structures, the figures of which are referred to: and, in-
deed, we should be altogether in uncertainty about the nature
of these very curious and interesting specimens, were it not
for the few words given in explanation of the plates ; ; and
these, too, are insufficient, The Plate in question contains
four ‘figures, not very artistic, certainly, but conveying a
general appearance of bone structures, as seen with high and
low powers. Figures 1 and 83 exhibit sections of a sort of
cancellated bone, not well expressed in the drawing ; magni-
fied, as we should have supposed, some 60 or 70 diameters ;
but to our astonishment we discovered that, according to Dr.
Hellier, they are magnified no less than two hundred dia-
meters. We have seen many specimens of bone from various
sources ; but lacunz of such minute dimensions we have never
previously observed. Referring to figure 4 in the same Plate,
we find some enormous isolated lacune, taken from the pre-
vious specimen; and as they are in diameter some ten or
fifteen times larger than those in that specimen, we ex-
pected to find that they had been magnified some two or three
thousand diameters. Imagine, therefore, our surprise at dis-
covering that they had been enlarged only 400 diameters, ac-
cording to the statement of Dr. Hellier! There is yet another
figure in this Plate, fig. 2, which we confess we do not quite
understand ; and the * bone with large lacunae,” said to be

TRANSACTIONS OF THE PATHOLOGICAL SOCIETY. 297

represented at letter c, we certainly have not been so fortunate
as to discover. Appended to the foregoing Paper, we find
a report, by Dr. Jenner, on the Microscopical Appearances of
the Osteoid Deposits in the Lungs, but were it not for the
heading, we might have some difficulty in guessing to what
the report in question referred, as there is nothing in it
bearing upon the subject of osteoid structures.

We must here close our notice of individual papers, which
has already occupied a larger space than we originally in-
tended. At the same time, it is fair to state that criticisms,
such as we have made upon those above noticed, are not ap-
plicable to others. Indeed, taken as a whole, the sixth volume
of the Transactions of the Pathological Society is probably
the best and most valuable that has been issued since its com-
mencement. Most of the communications are of much in-
terest; many are decidedly original, and to the majority we
can accord our unqualified approbation. We would now
venture to suggest to the future contributors of the Patholo-
gical Society, a few considerations which have occurred to us.

In the first place, we would urge the propriety of carrying
out the system of reports to a greater extent. As we have
before said, it gives safety, and consequently weight, to pub-
lished statements ; and care should always be taken to select
the riaht referee for the right specimen, about which, we should
presume, there cannot be much difficulty. Again, the method
of illustrating papers requires careful supervision. I[]lustra-
tions of pathological histology in one publication should, we
think, as far as possible, be rendered upon a fixed scale—say
by magnifying powers of hundreds or parts of hundreds—50,
100, 200, 400 diameters, and so on. If such a method were
adopted, it would give an intelligible relationship between
different Plates and figures, and a unity, not less agreeable than
useful, to the entire volume. One more suggestion: we would
recommend gentlemen who cannot draw from the microscope,
not to attempt it. Few things are more difficult than to ren-
der well upon paper, objects that are seen through the micro-
scope ; and it would be far better for observers to place their
specimens at once in the hands of Mr. Tuffen West, who il-
lustrates the Pathological Transactions, than to furnish him
only with ill-executed and incorrect representations of their
own. > Mr. Tuffen West combines in himself the accomplish-
ments of a good microscopist, and an artist of the nicest and
most accurate touch; and by his single exertions, in this
Journal and in the Transactions of the Pathological Society,
he has created a new era in the illustrations of normal and ab-
normal histology.

298 THE MICROSCOPE.

The members of the Pathological Society are under peculiar
obligation to Dr, Quain, their accomplished secretary ; who,
unassisted and alone, undertakes all the labour and responsi-
bility of the annual volume, and presents it to them with an
exact punctuality and completeness that do infinite credit to
the Editor,

Rustic ADORNMENTS FoR Homes or Tastr. By Surruey Hreperp.
London. Groombridge.

AuruouaH this work does not contain any microscopical matter
that we can criticise, we can, nevertheless, recommend it to our
microscopical fr iends, as containing a large amount of informa-
tion about things in which the oreat majority of them will be
interested. No microscopist should be without his aquavivarium,
sea and fresh water, to enable him to carry on observations on
the structure and habits of the creatures whose existence
depends on water. A Wardian case, too, in which to grow ferns
and other kinds of plants, will be necessary to those who are
investigating vegetable physiology. Even the most learned in
the construction of these things will be glad of additional hints,
and we can promise them many useful remarks, not only on
Aquariums and Ward’s cases, but on Aviaries, Apiaries,
Rockeries, Ferneries, and other things in this volume of Mr.

Hibberd’s.

THE Mricroscopr. By Dionystus Larpner, D.C.L. London. Walton
and Maberly.

Tuts book is a republication of an article on the microscope in
the Museum of Science and Art, and contains a yast quantity
of matter, for the small price at which it is published. As far
as the structure of the microscope goes, the descriptions and
illustrations are accurate enough, but in the department devoted
to the use of the microscope, ‘it is very much inferior to most
recent publications on this subject. The drawings of microsco-
pic ubjects are defective, and sometimes inaccurate, a necessary
consequence of their being selected from antiquated objects.
Dr. Lardner, however well acquainted with the optical principles
involved in the structure of the microscope, has certainly not
kept up with modern discoveries made by its aid. We cannot
but regret that so good an opportunity of etting out a cheap
book on the microscope should have been ‘fost fo for the want of
competent assistance in that part of the work devoted to the
practical applications of this instrument.

( 299 )

NOTES AND CORRESPONDENCE.

Microscopic Hints from Australia. —The Editors have received
a copy of the ‘Transactions of the Victorian Institute,’ in which
is a paper on ‘ Microscopic Investigation,’ by Mr. W. S. Gib-
bons. From this paper they give an extract, and also add some
illustrations, which have been forwarded to Mr. Jabez Hogg
by the Author, for the purpose of explaining some of the
apparatus he has successfully employed.

“Some years since I made some experiments in the use of
the air-pump in making microscopic preparations, believing that
it had not then attracted the attention of operators. Since
that time, I found in a recent work an account of some uses
- that had been made of that instrument, but that which I found
most advantageous was not mentioned, and appeared to have
escaped the experimenter; while that most dwelt upon in the
work in question is one that I abandoned as unavailing, nor
have I seen occasion to change the opinion. The operator
quoted immerses the objects in balsam, and then places them
on a dry hot-bath under the receiver of an air-pump ; the air is
supposed to be extracted by this process from the minute pores
or cells, and its place supplied by the balsam. I found, however,
that in the majority of cases the
viscidity of the balsam retains
the bubbles of air even when
they escape from the object, and
that many of them return to
their original positions on the
restoration of atmospheric pres-
sure. The plan I recommend
as preferable, is to immerse the
object in a bath of turpentine,
and exhaust it before applying
the balsam. The limpidity of
the turpentine allows the free
escape of air, and when the -
object is removed from the bath A: Conical tin-boiler, 5 inches diameter, to

vaporize a small quantity of water over

to be mounted, the balsam then hr Seeger ps est AE De We a
: : . Cage of perforated metal to hold the
blends with the turpentine, and ¢: objects C. It fits tightly at the collar

Fig. 2.
Steam Bath.

ae = = ke D, and is stopped by earth with a small
follows it into minute cavities aoe ieee ta ‘that ats teat axe
whither it could not alone have pass round the object.

penetrated.

300 MEMORANDA.

“ Before quitting the subject of mounting, I may mention that
I have found the common balsam of copaiba a useful medium
in which to preserve objects of a delicate character, which it
is not desired to mount immediately. I have used it cold, and
have mounted the objects in it temporarily between two plates
of glass; and have transmitted them by post and otherwise to
distant parts of the country in perfect safety; objects so pre-
pared may at once be mounted in Canada balsam without
further preparation. The advantage derived from the use of
copaiba is that it is not so viscid, and does not dry so rapidly as
the other balsam, while its refracting properties are so little
inferior that no detriment results from its use.

“The next point on which I have to make an observation that
1 believe to be original, is the mode of killing insects and other
small animals. <A paper recently read to the British Associa-
tion mentions that cyanide of potassium has been employed for
this purpose. I have had occasion to make some rather large
quantities of this salt for other processes, and contemplated the
employment of it as a means of destruction, for which its active
poisonous property eventually fits it, but I was so well satisfied
with other plans, that I have not yet tried it. I find that im-
mersion in turpentine kills small insects almost instantaneously,
and has the great advantage of making them protrude their
probosces, lancets, and other organs—a very desirable effect ;
they are also more readily saturated and rendered diaphanous
than after they have been allowed to harden. If it is intended
to dissect the internal organs this plan wll not do, and Swam-
merdam’s plan of suffocating the animals in spirits will be found
almost as rapid, and much more suitable. But the agent I most
incline to in cases when turpentine is inadmissible, both on the
ground of humanity, as causing speedy death, and for its pre-
servative quality, which renders it suitable for the cabinet, is
creosote. If the mouth and spiracles be touched with a pencil
dipped in it, the creatures most tenacious of life soon yield to
its influence. The use of spirit to suffocate the animal, and the
exhibition of creosote to its mouth, &c., both present the advan-
tage of hardening the viscera, which is very desirable, as it
tends materially to assist the process of dissection—at least so
long as the albuminous portions are not so much coagulated as
to make the delicate organs cling together. There is risk, how-
ever, that cyanide of potassium would corrode delicate organ-
isms, and thus be productive of mischief. Small soft-bodied
animals are, by soaking in spirit, rendered less liable to injury
in the process of compression.

“For the purpose of collecting aquatic animalcules, I use, in
preference to any kind of net, stout tin hoops, about four inches

MEMORANDA. 301

diameter and one and a half deep, nested for stowage, Muslin
of different degrees of fineness is strained over one opening of
the hoop, and a screw is attached by its head to the rim. The
net is thus portable, and is screwed into a hole in the end of a
walking-stick, or what is better a fishing-rod. I find that for
most purposes the fabric called bobbinet answers very well, and
catches creatures much smaller than its own meshes, while the
free escape of water through the openings prevents their being
washed out, as they frequently are in withdrawing the net from
the surface. If the stick have a spike at the other end it may
be stuck in the ground, and those animals that are visible to the
naked eye leisurely picked out, with a small thin spoon or
palette-knife, and transferred to bottles, care being taken that
the more voracious ones be separated from their prey ; while the
thick residuum, containing infusoria, &c., may be ladled up or
strained off into its appropriate vessel. On arriving home the
contents of the bottles are poured into one of the finer nets,
which is placed in a saucer of water. The drafting net is then
lifted up out of the water, and a final classification may be made.
‘Vo catch individual creatures that are too large for a fishing-
tube, a small spoon-net, made of slips of thin metal, bent into
the form of a spoon, with a large hole punched out of the bowl,
and muslin cemented to the rim, will be found convenient.
This form of net is free from the inconvenience of loose parts
of material, in which choice specimens may be confused and
lost.

Animaleule Net.

“ Before concluding this paper, 1 may mention a very useful
cement, for fine work, which was communicated to me by my
friend Mr. Capewell, of Ballan. Canada balsam is heated and
evaporated to dryness, and the residual resin dissolved in ether.
This cement dries as rapidly as collodion, is perfectly limpid,
and does not coagulate.

“T hope soon to submit to the Institute a section-cutting
machine, which I am constructing on a plan different to any
I have yet met with, and presenting, as I fancy, some con-
veniences. I have here some sections cut with it in its present
state, but it is not yet mounted.”

302 MEMORANDA.

Through the kindness of Mr. Jabez Hoge the editors are
enabled to present a drawing of this machine.

Fig. 1.

>

The Cutting Machine.

A A, consists of a stout brass frame, having an opening in the top plate.

B. Orifice of a tube half an inch diameter and one and a half long.

C. Loose piston working freely in the tube, and steadied by the slot in the
side.

D, is a female screw, to which motion is given by the toothed wheel.

E. The teeth, which answer the triple purpose of thumb-milling, ratchet-
stop, and graduation.

F. Block of wood, with rabbet to hold on the edge of a table. This machine
is self-regulating, and may be worked as rapidly as the skill of the
operator will allow. It admits also of very fine graduation.

New method of disintegrating VHasses of Fossil Diatomacex,.—
Many masses of fossil Diatomacez are so strongly coherent,
that they cannot be diffused in water, (for the purpose of
mounting in balsam,) without a degree of mechanical violence
which reduces to fragments many of the most beautiful and
interesting forms. This is particularly the case with some
specimens from the “ infusorial deposits” of California. Some
of these I endeavoured to break up, by boiling in water and
in acids, and also by repeated freezing and thawing when
moistened, but without good results in either case. At last it
occurred to me that the adherence might be due to a slight
portion of a siliceous cement which the cautious use of an
alkaline solution might remove without destroying any but
the most minute shells of the Diatoms. As the case appeared
a desperate one, a “‘ heroic remedy” was applied, which was
to boil small lumps of the diatomaceous mass in a strong solu-
tion of caustic potassa or soda. This proved to be perfectly
efficacious, as the masses under this treatment rapidly split up
along the planes of lamination, and then crumbled to mud,
which being immediately poured into a large quantity of
water ceased to be acted upon by the alkali, and gave when
thoroughly washed, not only all the large shells of the Diatoms

MEMORANDA. 303

in a state of unhoped for perfection, but also furnished abun-
dance of the minute forms. Having obtained by this method
highly satisfactory results from specimens from many localities,
I can confidently recommend it as an addition to our modes
of research.

The following directions will enable any one to apply the
process, Put small lumps of the mass to be examined into a
test tube, with enough of a solution of caustic potassa or soda
to cover them; then boil over a spirit lamp for a few seconds,
or a few minutes, as the case may require. If the solution is
sufficiently strong, the masses will rapidly crumble to mud,
which must be poured at once into a large quantity of water,
which after subsidence is removed by decantation. If the
mass resists the action of the alkaline liquor a still stronger
solution should be tried, as while some specimens break up
instantly in a weak solution of alkali, others require that it
should be of the consistence of a dense syrup. The mud also
should be poured off as fast as it forms, so as to remain as
short a time as possible in the caustic ley.

The only specimens which I have found not to give good
results by the method above given, are those from Tampa Bay,
Florida, and the infusorial marls from Barbadoes. In the
masses from Tampa the lapidification is so complete, that the
alkali destroys the shells before the lumps break up; and in
the case of the Barbadoes marls the cementing material is cal-
careous, and requires a dilute acid for its removal. In apply-
ing the above process one caution is necessary, which is
to thoroughly wash the shells with water, and not with acids,
as the latter will cause the deposit of a portion of the dis-
solved silica and materially injure the beauty of the speci-
mens. When the washings are no longer alkaline, the
specimens may then be thoroughly cleansed by acids or by
the chlorate process described in the last number of this
Journal, (Vol. xxi. p. 145.)—J. W. Baitry, American Journal
of Science and Arts, 2nd Series, Vol. X XI, May, 1856.

Om the Non-Existence of Polarizing Silica in the Organic King-
It is now more than twenty years since Sir David
Brewster announced the existence of polarizing or doubly-re-
fractive silica in the cuticle of Equisetum, and in that of some
of the grasses. In Lindley’s ‘ Natural System of Botany,’ the
following account of Brewster’s experiments is given :— On
subjecting a portion of the cuticle of Equisetum hyemale to the
analysis of polarized light under a high magnifying power,
Brewster detected a beautiful arrangement of the siliceous
particles, which are distributed in two lines parallel to the
axis of the stem and extending over the whole surface. * * *

donis.

304 MEMORANDA.

Brewster also observed the remarkable fact that each particle
has a regular axis of double refraction. In the straw and chaff
of wheat, barley, oats and rye he noticed analogous pheno-
mena.” (Quoted by Lindley from Grevill. Fl. Edinens., 214.)

In Quekett’s ‘ Treatise on the Microscope,’ 3rd ed., p. 358,
directions are given for preparing the siliceous cuticle of
Equisetum hyemale for microscopic examination, by boiling in
strong nitric acid, and it is added that “in balsam it forms a
beautiful object for polarized light.” Similar directions are
given for preparing the silica in the chaff of wheat, oats, &c.

As these statements are contained in the last editions of
each of the above-mentioned works, it is evident that no con-
tradiction of the error involved in them has been pointed out ;
yet, notwithstanding the high authority on which they rest,
the statements so far as the polarizing action of the silica is
concerned are wholly erroneous. If the cuticle of the above-
mentioned plants is completely deprived of its carbonaceous
tissues, it will be found wholly devoid of action on polarized
light, and any preparation of the cuticle which is found to
affect polarized light will also be found to blacken when
heated in concentrated sulphuric acid, and if then decar-
bonised by throwing into the hot acid solution a little chlorate
of potassa, the residual silica shows no signs of action under
the polariscope, either alone or with the selenite plate,
although it still retains the forms of the cells, stomata, &c.

It is clear then that the error in the above statements has
been caused by the imperfect removal of the dense carbona-
ceous tissues which are deposited beneath the silica. I have
examined several species of Equisetum, and a large number of
plants of the grass tribe which are most remarkable for their
siliceous cuticles, but have found no trace of any action upon
polarized light, when the carbonaceous matter was removed.
But it is unnecessary to resort to artificial preparations to
prove the correctness of my statements. Nature has made
her own preparations, and deposited them by myriads beneath
every peat bog, where may be found not only the siliceous
shells of the Diatoms, and the spicules of the fresh-water
sponges, but also a large number of the siliceous parts of the
grasses, sedges, &c. Ehrenberg has shown, (Berlin Monthly
Reports, May, 1848,) and I can confirm his statements, that
the silica in these Phytolitharia, as well as in the Diatomacee,
Polycistinee and Spongiolites is not doubly refractive. He
makes an exception in the case of the shell of Arachnoidiscus,
but my own experiments prove that when properly cleaned
this shell forms no exception. As I have shown above that
the silica in the cuticle of the Hguisetum and grasses, agrees
with that in the lower tribes in characters, I think the conclu-

MEMORANDA. 305

sion is warranted, that doubly refractive silica has no existence

in the organic world.—J. W. Baiwey, Ibid.

On some Specimens of Deep Sea Bottom, from the Sea of Kamt-
schatka, collected by Lieut. Brooke, U.S. n.—The fol lowing is a
copy of a letter from Professor Bailey to Lieut. Maury, of the
National Observatory, Washington, D. C., dated West Point,
New York, January 29th, 1856.

I have examined with much pleasure the highly interesting
specimens collected by Lieut. Brooke, of the U. 8S. Navy,
which you kindly sent me for microscopic analysis, and [ will
now briefly report to you the results of general interest which
I have obtained, leaving the enumeration of the organic con-
tents and the description of the new species for a more detailed
account which I hope soon to publish.

The specimens examined by me were as follows :

No. 1. Sea bottom 2700 fathoms, lat. 56° 46' N., long. 168°
18 E., brought up by Lieut. Brooke with Brooke’s lead.

No. 2. Sea bottom 1700 fathoms, lat. 60° 15’ N., long.
170° 53’ E., brought up as above, July 26th, 1855.

No. 3. Sea bottom 900 fathoms, temperature (deep sea)
32 Saxton, lat. 60° 30' N., long. 175° E.

A careful study of the above specimens gave the following
results.

1st. All the specimens contain some mineral matter, which
diminishes in proportion as the depth increases, and which
consists of minute angular particles of quartz, hornblende,
feldspar, and mica.

2nd. In the deepest soundings (No. 1. and No. 2.) there is
least mineral matter, the organic contents (which are the same
in all) predominating, while the reverse is true of No. 3,

3rd. All the specimens are very rich in the siliceous shells
of the Diatomacee, which are in an admirable state of preserv-
ation,—frequently with the valves united and even retaining
the remains of the soft parts.

Ath. Among the Diatoms, the most conspicuous are the
large and beautiful discs of several species of Coscinodiscus.
There is also (besides many others) a large number of a new
species of Rhizosolenia, a new Syndendrium, a curious species
of Chetoceros with furcate horns, and a beautiful species of
Asteromphalus, with from five to thirteen rays, which I pro-
pose to call Asteromphalus Brookei, in honour of Lieut. Brooke,
to whose ingenious device for obtaining deep soundings, and
to whose industry and zeal in using it, we are indebted for
these and many other treasures of the deep.

5th. The specimens contain a considerable number of the
siliceous spicules of sponges, and of the beautiful siliceous

306 MEMORANDA.

shells of the Polycistinee. Among the latter I have noticed
Cornutella clathrata, Khr., a form occurring frequently in the
Atlantic soundings. I have also noticed in all the soundings
(and shail hereafter describe and figure) several species of
Eucyrtidium, Halicalyptra, Perichlamidium, Stylodictya, and
many others.

6th. I have not been able to detect even a fragment of any
of the calcareous shells of the Polythalamia. This is remark-
able for the striking contrast it presents to the deep soundings
of the Atlantic, which are chiefly made up of the calcareous
forms. This difference cannot be due to temperature, as it is
well known that Polythalamia are abundant in the Arctic seas,

7th. These deposits of microscopic organisms, in their
richness, extent, and the high latitudes at which they occur,
resemble those of the Antarctic regions, whose existence has
been proved by Ehrenberg; and the occurrence of these
northern soundings of Asteromphalus and Chetoceros, is another
striking point of resemblance. These genera, however, are not
exclusively polar forms, but, as I have recently determined,
occur also in the Gulf of Mexico and along the Gulf Stream.

8th. The perfect condition of the organisms in these sound-
ings, and the fact that some of them retain their soft portions,
indicate that they were very recently in a living condition,
but it does not follow that they were living when collected at
such immense depths. As among them are forms which are
known to live along the shores as parasites upon Alga, &e., it
is certain that a portion at least have been carried by oceanic
currents, by drift ice, by animals which feed upon them, or
by other agents, to their present position. It is hence proba-
ble that all were removed from shallower waters in which they
once lived. ‘These forms are so minute, and would float so
far when buoyed up by gases evolved during decomposition,
that there would be nothing surprising in finding them in
any part of the ocean, even if they were not transported (as it
is certain they sometimes are) by other agents.

Jth. In conclusion, it is to be hoped that the example set
by Lieut. Brooke will be followed by others, and that in all
attempts to obtain deep soundings the effort will be made to
bring up a portion of the bottom. The soundings from any
part of the ocean are sure to yield something of interest to
microscopic analysis, and it is as yet impossible to tell what
important results may flow from this study.

The above is only a preliminary notice of the soundings
referred to. I shall proceed without delay to describe and
figure the highly interesting and novel forms which I have
detected, and I hope soon to have them ready for publication,
—J. W. Baitey, American Journal of Science and Art, 1856.

(S07 *»)

PROCEEDINGS OF SOCIETIES.

Microscoricau Soctety, March 26, 1856.
GrorGE SHADBOLT, Esq., President, in the chair.

W. Fuller, Esq., Harley-place, Bow-road; W. W. Armstead,
Esq., 35 Belitha Villas, Barnsbury Park; G. J. Brownlow, Esq.,
Alfred-place, West, Thurloe-square; and E. O. Spooner, Eagle
House Blandford, were balloted for, and duly elected Members of
the Society.

The following Papers were read: “‘ On the Post-tertiary Diato-
maceous Sand of Glenshira,” by Professor Gregory (see Transactions,
vol. iv., p. 35).

Notes on some Fresh-water Confervoid Algz, by Arthur Henfrey,
Esq. (see Trans., vol. iv. p. 49).

* On the Illumination of Opaque Objects under the highest
powers of the Microscope,” by F. H. Wenham, Esq. (see Trans.,
vol. iv., p. @5).

April 30, 1856.
GEORGE SHADBOLT, Esq., President, in the chair.

The Hon. and Rey. 8S. G. Osborne, Blandford, Dorset ; H. Druce,
Esq., George-street, Chelsea; and Henry Pollock, Esq., George-
street, Hanover-square, were balloted for, and duly elected Members
of the Society.

The following Papers were read: ‘‘ Discussion on an Object
Compressor for preparing and mounting Objects,’ by F. Hislop,
Esq.

“On defining the position and measuring the magnitude of
Microscopic Objects,” by R. J. Farrants, Esq.

Mr. Busk gave an account of Mr. Dobson’s observations on Loap
or Lerp, the eup-like covering of Phyllide found on the leaves of
certain Bucalypti.

( 308 )

ZOOPHYTOLOGY.

1. Polyzoa cheilostomata.
Gen. 1. Membranipora, Blainville. (‘ Brit. Mus. Cat.,’ p. 56.)
1. M. hexagona, Busk. Pl. XIL, fig. 4.

Area of cell hexagonal, or sub-elliptical ; surface smooth ; septa smooth,
even ; mouth semilunar. .
Flustra coriacea, KE. Forbes; Johnston, ‘ Brit. Zooph.,’ p. 348. Pl.
LVI., fig. 8 (mon ‘ Esper Pflanzth.
Flust.,’ Tab. vii., fig. 2; Busk, ‘ Brit.
Mus. Cat.,” p. 57. Pl. LXXIIL, fig.
4, 5).
Hab. Coast of Devon, Miss Cutler; Isle of Man, E. Forbes; Fowey
harbour, Peach; Sana Island, Hyndman.

The species figured by Esper, under the name of F. coriacea,
is clearly not the same as the one here represented, which seems
to correspond with E. Forbes’ description and Dr. Johnston’s
figure. Esper’s figure corresponds more nearly with the M7

coriacea of the Brit. Mus. Catalogue, which is also a British
form. For the specimen from which the present figure was
taken, I am indebted to Miss Cutler.

Gen. 2. Lepralia, Johnston.
1. L. ringens, n. sp. Busk. PI. IX,, figs. 3, 4, 5.
Cells ovate, with a circumscribed area in front; surface minutely punc-
tured, scaly ?; a vibraculum on the front or side of the cell; mouth ex-

panded below the base of the moveable lip into a transverse, sub-crescentic
fissure ; 4 to 6 marginal spines.

Hab. Shetland, on stone, Barlee. (In the Newcastle Museum, pre-
sented by Dr. Edward Charlton.)

A curious form which, as Mr. Alder; to whom I am indebted
for the drawings from which the figures are taken, remarks, “ has
very much the appearance of a Membranipora, filled in with
calcareous matter similar to the rest of the cell. ‘There is a
strong raised rim in the same position as in [some] Membrani-
pore. ‘The mouth is very curious. There is a wide transverse
aperture, edged with a horny substance, below what appears to
be the true mouth covered with the horny operculum; but I
cannot,” he says, “make out whether or not there is any
calcareous division between the two. In the freshest cells the
surface, when highly magnified, has a beautiful scaly appearance,
each scale being perforated (vide fig. 5). In the older cells the
perforations only appear.”

2. L. fissa, n.sp. Busk. Pl. [X., figs. 8, 9, 10.
Cells ovate, immersed, quincuncial, or disposed in parallel contiguous

ZOOPHYTOLOGY. 309

rows ; surface smooth. Mouth raised, deeply sinuated below, with two
or three unequal teeth on either side; four superior, marginal spines.
Ovicell globose, with a triangular vertical fissure in front. Avicularia of
various sizes distributed irregularly over the polyzoary.

ee Guernsey, J. Alder; Coast of Devon, Miss Cutler; Exmouth,
artee,

The foregoing Lepralia was long since brought under my
notice by my esteemed friend, Mrs. Gatty, to whom zoophy-
tologists are under many important obligations.

3. L. lata,n. sp. Busk. PI. X., figs. 1, 2.

Cells broadly-ovate, immersed, quincuncial ; surface punctate or pitted,
more especially around the border. Mouth rounded above, contracted
below the middle, with a straight lower lip; margin slightly thickened.

Ovicell rounded.
Hab. Bay of Gibraltar, on Shell, Dr. Landsborough.

4. L. unicornis, Johnston, Pl. X., figs. 3, 4.

This is the same species as the one figured in Pl. LXXXI.
of the ‘ Brit. Mus. Cat.,’ where it is regarded as a variety of
L. spinifera, but I now think erroneously ; whether it differ,
however, from Dr. Johnston’s Z. ansata is far more doubtful ;
I am inclined to think that Z. ansata is nothing more than
L. unicornis, with the two avicularia. It is sometimes without
those appendages at all, sometimes has one, and very often
two. The latter form seems to be identical with the Cellepora
Dunkeri of Reuss (‘ Fossil. Polyp. d. Wiener tertiar. Beckens,’
Peek, tr 27),

5. L. Peachii, Johnston. (Brit. Mus. Cat., p. 77.) Pl. X., figs. 5, 6.
(Var. labiosa).

This thick-lipped variety, as I suppose it to be, of L. Peachii,
was collected by Mr. Alder in the Island of Guernsey ; I have
it also from Belfast Bay, collected in deep water by the late Mr.
Thompson.

6. L. pallasiana, Moll. (Brit. Mus. Cat.,p.81.) PI. XI., figs. 1—2.
(Var. armata.)

Most of the cells having an avicularium immediately below the mouth

in front ; mandible rounded.

Hab. Tenby, Busk.

This Lepralia agrees so perfectly in all other respects with
L. pallasiana, that it is impossible, I think, to separate them
merely on account of the existence of the avicularium below the
mouth.

7. L. Landsborovii, Johnston. (Brit. Mus. Cat., p. 66.) Pl. XL, fig. 3.

The species here figured, appears to correspond in most par-
ticulars with that described by Dr. Jolnston under the above
appellation, of which the only specimen with which I am ac-

VOL. IV. Y

310 ZOOPHYTOLOGY.

quainted is in his collection in the British Museum. The pre-
sent figure was taken from a specimen collected by Mr. Alder,
in Guernsey or Jersey ; it was on an oyster-shell.

8. L. punctuta, Hassal. (Brit. Mus. Cat., p. 79.) Pl. XI., figs. 4, 5.

The form here figured seems to correspond with L. punctata,
in its most perfect state; it was collected in Gibraltar Bay,
growing on shell, by the late lamented Dr. Landsborough.

9. L. californica, n. sp. Busk. Pl. XL, figs. 6, 7.

Cells broadly-ovate, surface minutely punctured; a lunate pore in front,
a little below the mouth; an avicularium on either side above. Mouth
rounded above, lower lip straight, four superior marginal spines. “Ovicell
small, sub-immersed.

Hab. California, Dr. Gould.

The specimen of this well-marked species was furnished to
me by the kindness of Dr. Philip Carpenter. In the older
cells the front is so much raised, that the mouth and the lunate
pore, with the surrounding part of the surface of a triangular
shape, lie in an almost horizontal plane.

Gen. 3. Alysidota, n. gen. Busk.

Char. “ Cells disposed in a single series, branching irregularly ; one
cell arising from another by a broad base. Surface usually punctured.”

In the ‘ Brit. Mus. Cat.’ of Marine Polyzoa, p. 82 (PI.
XCIL., figs. 1, 2, 3), a species of Lepralia is described, and
ficured under the specific name L. labrosa, in which the cells
ave disposed for the most part in linear series, branching out
irregularly from a central point, where some of the cells are
crowded together without any definite order. In the absence
of other forms having a similar mode of growth, it seemed
better to include this species under Lepralia, of which it might
be regarded as an aberrant form, and to which, at any rate, it
appeared to be very closely allied, than to erect it into the type
of a distinct generic group.

Lately, however, we have been furnished by Mr. J. Alder,
with another form apparently very closely related to the
above in its mode of growth; and it would now seem justi-
fiable to constitute of these dendritic polyzoaries a separate,
perhaps subgeneric group, of which ZL. labrosa, Busk (¢ Brit.
Mus. Cat.,’ p. 82, Pl. XCII., figs. 1, 2, 3), would form the
type. The name is taken from the chain-like disposition of
the cells.

The genus differs from Lepralia in the disposition of the
cells, which are, for the most part, arranged in linear series,
branching out in various directions in a dendritic manner.
From Hippothoa, it is distinguished by the circumstance, that
the cells arise from each other by a broad base, and are not

ZOOPHYTOLOGY. okt

contracted below into a tube, and that the branches are given
off more irregularly, and not from the sides of the cells, but
from the upper and back part of the eell from which they
spring.

1. A. Aldert,n. sp. Busk. Pl. IX., figs. 6, 7.

Cells ovate broad, surface punctate, verrucose round the border; an
umbo in front. Mouth circular with a sinus in the lower border, margin
very slightly thickened. Ovicell globose, keeled in front, with a small
central umbo.,

3 Gen. Hschara, Ray. (‘ Brit. Mus. Cat.’ p. 89.)
* Foliaceous.
1. H. cribraria, Johnston. Pl. X., figs. 7, 9.

Cells punctured, oval or rhomboidal, the aperture in the mature one
with a blunt mucro below ; an avicularium on each side of the mouth.
Mouth orbicular, margin simple, thin.

Hab. Berwick Bay, 35 fms, Dr. Johnston ; Coast of Northumberland,
deep water, A. Hancock, W. King, J. Alder.

The beautiful Eschara here figured, appears to correspond
so closely with Dr. Johnston’s description of /. cribraria, that
there would appear to be little doubt of its really being the
form understood by him under that appellation. His figures,
however, are bad, and seem to have been taken from an old or
worn specimen, and it is not easy to reconcile them with his
verbal account.

The species was first brought to my notice by Mr. J. Alder,
who kindly furnished me with the two smaller specimens
figured in the plate, and, at the same time, was good enough to
supply outline figures of the larger growths there shown. He
informs me that several specimens of it exist in the Newcastle
Museum, where they were placed by Mr. King, and labelled
E. foliacea ; he states, also, that Mr. A. Hancock obtained it,
many years ago, by dredging in deep water. The mode of
growth of the young polyzoary is remarkable. It clasps, by a
contracted base, the branch or branches of a Sertularia or
Fucus, and the two planes of cells turn round the support, and
apply themselves back to back. This mode of origin, however,
is not altogether peculiar ; for it obtains in more than one other
species of Eschara, an instance of which may be seen in M.
Edwards, Sur les Eschares, Pl. IIL, fig. 1d, in the case, un-
doubtedly, of EH foliacea.

2. Polyzoa cyclostomata.
Gen. 1. Alecto, Lamx.
1. A. granulata? W. Thompson. PI. IX., figs. 1, 2.

The figure is taken from a drawing by Mr. J. Alder of a specimen
apparently of the above species, exhibiting a peculiar mode of growth,

growing on a stone from Shetland. It bears a close resemblance to
Alysidota,

(312)

ZOOPHY TOLOG Y.

DESCRIPTION OF PLATES.

Puate [X.
Fig.
1.—Alecto granulata? natural size.
2.— Id. magnified. J. Alder, del.
0.—Lepralia ringens.
4.—Single cell, more highly magnified.
5.—Surface of cell more highly magnified. J. Alder, del.
6.—Alysidota Alderi, natural size.
7.—Portion magnified. J. Alder, del.
8, 9.—Lepralia fissa.
10.—Young cell from edge of patch.
PLaTE X.
1, 2.—Lepralia lata.
3, 4.—L. unicornis.
5, 6.—L, Peachii (var. labiosa),

Puate XI.
1, 2.—Lepralia pallasiana (var. armata).
3.—L. Landsborovii ?
4, 5.—L. punctata ?
6, 7.—L. californica.

PuaTe XII.
1, 3.—2Hschara cribraria,
4.—Membranipora hexagona,

T OLOGY.

ZOOP HY

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Plate IX.

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ZOCPHYTOLOGY

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ZOOFEHY TOLO GY.
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iii

TRANSACTIONS OF MICROSCOPICAL SOCIETY.

DESCRIPTION OF PLATE IV.,,

Hlustrating Professor Henfrey’s paper on some Fresh-water Con-
fervoid Alge, new to Britain.

Figs. 1—25, Pandorina Morum, Ebr.
Fig.

1 —Perfect form, with 16 gonidia, side view.
2.—Ditto, polar view.
3.—Perfect form, with 32 gonidia, side view.
4.—Ditto, polar view.
5.—A gonidium, side view.
6.—Ditto, from above.
7 and 8.—Side and end view of a small frond, with 16 gonidia.
9.—Side view of a small frond, with 32 gonidia.
10.—A frond, with the gonidia dividing.
i1.—A more advanced frond.
12.—A frond, with the young ones nearly perfect.
13 and 14.—Young fronds free.
15 to 20.—Side and end views of fronds, with the gonidia pushed close
together.
21.—Side of a frond, like fig. 15, with the gonidia encysted, their contents
turned red, and the gelatinous envelope nearly dissolved.
22.—End view of the same.
23.—Side view of one with 32 gonidia, more magnified.
24.—Resting-spores (encysted gonidia) free.
25.—One more magnified, to show the membranous coat.

Figs. 26 and 27, Apiocystis Brauniana, N ageli.

26.—A half-grown frond.
27.—Green gonidia from the interior, the lower ones dividing.

Figs, 28—36, Clathrocystis ceruginosa, Henfrey.

28 to 31.—Successive stages of development of a frond.

32 to 84.—Fragments of a broken-up frond, like fig. 31.

35.—Green cells from the interior of the gelatinous fronds, some under-
going division.

36.—One more magnified, to show the membranous coat.

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TRANSACTIONS OF MICROSCOPICAL SOCIETY.

DESCRIPTION OF PLATE V.,
Illustrating Dr. Gregory’s paper on the Glenshira Sand.

Fig.
1.—Navicula rhombica, n. sp. A frequent variety ; S. V.
a «CS s Front view, showing several grouped in a pack,

2.—N. maxima, n.sp. 2*.—Ditto, narrow variety. 2**.—Intermediate
form of N. maxima.

3.—N. Hennedyi, 8m. (Not figured in Synopsis, vol. ii.)
4.—N. latissima, n. sp. 4*.—Ditto, longer variety.
5.—WN. quadrata, n. sp. (= N. humerosa, Bréb.)
6.—N. formosa, n. sp.
7.—N. pulchra, n. sp.
8.—N. angulosa, n. sp.
8*.— 22 B.
9.—N. Macula, n. sp.

10.—N. solaris, n. sp. 2 figures.

11.—N. ? Pandura, Bréb. (?).

12.—N. ? nitida, Sm.

12*.— =F ?

13.—N. incurvata, n. sp.

14.—N, splendida, n. sp.

15.—WN. didyma, y. Costate striz.

16.— 3 , 5. A new variety.

17.—N. clavata, n. sp.

18.—Pinnularia longa, n. sp.

19.—P. fortis, n. sp.

20.—P. inflexa, n. sp.

21.—P. acutiuscula, n. sp.

22.—P. Ergadensis, n. sp.

23.— Stauroneis amphioxys, un. sp.

The figures in this plate represent, for the most part, full-sized or large
individuals under a power of 400 diameters. No. 9, Navicula Macula, is
represented under a somewhat higher power; but I believe there are
individuals of equal size under 400 diameters.

The remainder of the new forms which I have described in the Glenshira
Sand, and several of which are very curious, will be figured in the next
Number of the Journal.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE XIV.,

Illustrating Dr. D’Alquen’s paper on the Structure of Oscillatoria.
Fig.
1—-Portion of a filament of Oscillatoria contexta, showing the striated
proper cell-membrane.
2.—A detached empty piece of this cell-membrane.
3.—Portion of filament treated with iodine.
a. Entire portion.
b. Proper cell-membrane slightly affected by the reagent.
ce. The plain unstriated cellulose sheath or tube.
d. Single joint on end.
4.—Portion of filament treated by weak syrup.
5,—Ditto by a strong solution of chloride of calcium.
6.—Ditto by a weak ditto.
7.—Ideal section of a filament, showing the concentric arrangement of its
different tissues.
a. Vertical section.
b. Horizontal section.
c. Solid axis.
d. Layer of protoplasm coloured by chlorophyll.
e. Proper cell-membrane.
8.—Portion of filament, displaying the manner in which the cell-contents
are sometimes observed to separate while under the action of iodine.
9.—a. Portion of filament. ‘
b. The same as seen on end, having the appearance of a lenticular
disk.
10.—Portion of filament after desiccation and treatment by iodine, show-
ing the shrunken axis of the filament in the form of a green thread.
11.—Ditto not dried, showing this thread between the separated portions
of the filament.
12, 13.—Filaments with modified cells representing gonidia.
14,.—A new species of Oscillatoria, having its cells not coloured by
chlorophyll.
15.—The same, with some of its cells filled out.

Illustrating Dr. Lankester’s paper on Fungi in drinking water.

16.—Mycelium of Fungus. «a, enlargements seen on larger branches.
17.—Particles passing through the branches of the Mycelium.
18.—Spore case of the same Fungus.

19.—Mycelium of a Fungus. 6, moving particles.

JOURNAL OF MICROSCOPICAL. SCIENCE.

DESCRIPTION OF PLATE XVI.,

Illustrating Rev. J. B. P. Dennis’s paper on a Fossil Bone,
supposed to be Mammalian.
Fig.
1.—Represents the fossil rib from Lyme Regis. Natural size.
2.—Tangential section. Magnified 100 diameters.
2 a.—Portion of the above, at a, showing the character of the lacunez and
canaliculi, in connexion with an haversian canal. Magnified
400 diameters, for comparison with fig. 8.
2 6.—Portion of fig. 2, at b. Magnified 400 diameters.
3.—Longitudinal section of the Lyme Regis bone, magnified 100 dia-
meters, to show the general arrangement of the lacuna.
4.—Single lacuna of fossil. Magnified 400 diameters.
Figures A to G represent typical lacunz under the same
degree of enlargement.
A. Human. B. Tiger. Mammalian. ©. Boa Constrictor.
- D. Crocodile. E. Fossil Saurian from Stonesfield.
F. Turtle. Reptilian. G. Conger Eel. Fish
5.—Fossil Saurian from Stonesfield. Magnified 100 diameters.
6.—Lyme Regis fossil, vertical. Magnified 400 diameters.
7.—Tertiary Mammal. Magnified 400 diameters.

8.—Walrus, transverse ; lacunx in the neighbourhood of an haversian
canal. Magnified 200 diameters.
9.—Fossil Cetacean. Magnified 400 diameters.

10.—Fossil Elephant. Magnified 400 diameters.

11.—Ant-eater. Magnified 400 diameters.

12.—Sloth. Magnified 400 diameters.

13.—Dolphin. Magnified 400 diameters.

14.—Dugong. Magnified 400 diameters.

The resemblance of this latter to the fossil in question is very
striking.

15, 16, 17, 18.—Ant-eater, Sloth, Dolphin, and Dugong, magnified 100
diameters, to show the general arrangement of the lacune and
canaliculi.

19.—Crocodile, transverse. Magnified 200 diameters.

20.—Toad, tibia, vertical. Magnified 200 diameters.

21.—Sturgeon fin, vertical. Magnified 200 diameters.

22,—Fossil fish (Pyenodontus), from Stonesfield.

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JOURNAL OF MICROSCOPICAL SCIENCE.

DESCRIPTION OF PLATE XVII.

Illustrating Mr, Brightwell’s second communication on the
Genus Triceratium.
Fig.
1.—T. exiguum, W. Sm. 3, front view.
2.—T. parmula (n. sp.)
3.—T. brachiatum (n. sp.)
4.—T. truneatum (n. sp.)
d.—T. venosum (n. sp.)
6.—T. coniferum (n. sp.). 6, partial front view.
7.—T. Farus B.
8.—T. formosum y.

9.—T. armatum, Roper. 9 6b, front view. Dr, Bailey’s figure of 7.
setigerum (Smith’s Contr. 1854) very strongly resembles ours.

10.—T. armatum, a.

11.— ‘i B. 11), front view of a four-sided specimen.
12.— aa 7.

13.—T. marginatum (n. sp.)

14.—T. radiatum (n. sp.)

15.—T. Tabellarium (n. sp.)

16.—T. hyalinum (n. sp.)

17.—T. Marylandicum (n. sp.)

18.—T. punctatum (n. sp.)

19.—T. variable (n. sp.) Three of the very numerous and bizarre forms
of this curious species are represented.

20.—T. orbiculatum, Shadbolt. 5, front view.

* The figures are all magnified 400 diameters, with the exception of figs. 5, 6, 7,
8, 9,10, 12, 13, 14, 20, which are only X 300.

INDEX

VOLUME

TO JOURNAL.

Ve

A.

Acanthometra, 75,

Actiniscus, 75.

Actinophrys Sol, J. Weston on, 116.

Algie, on the Impregnation and Ger-
mination of, by M. Pringsheim, 63,
124,

Amyloid, degeneration on the course
of the, 135.

Amyot, T. E., on ‘‘ Finders and In-
dicators,”’ 153.

a on his “‘ Finder,” 243.

Anguinella palmata, 95.

Animalcule net, 301.

Antheridia, on the Phytozoa of, 51.

Aperture of object-glasses, F. H.
Wenham on, in reply to Professor
Bailey, 85.

Aperture of object-glasses, F. H.
Wenham on the, 239.

* Aperture of Object-glasses,” Re-
marks on Mr. Wenham’s paper on
the, by Professor Bailey, 160.

Appendicularia fiabellum, observa-
tions on the structure of, by T. H.
Huxley, 181.

Asterolampra pelagica, 75.

Asterosporium Hoffmanni, 192.

B.

Bacteriastrum, 75.

Bailey, Professor, remarks on Mr.
Wenham’s paper on the “ Aperture
of Object-glasses,”’ 160.

Bailey, J. W., on a Universal Indi-
cator for Microscopes, 55.

” on disintegrating dia-
tomacer, 302.
Pr on polarizing silica,

303,

Blow-fly, G. Hunt on the Proboscis
of the, 238.

Bone, microscopic structure of, 261.

Brightwell, Thomas, on the filamen-
tous long-horned diatomacex, 105.

ep on the genus Tri-
ceratium, 272.

Busk, G., on the structure and rela-
tions of Sugitta bipunctata, 14.

C.

Camphor-erystals, Joseph Spencer on
the similarity of forms of, with
those of snow, 201.

Carpenter, W. B.; The Microscope
and its Revelations, review of, 231.

= Researches on
the Foraminifera, 171.

Cellepora, new species of, 179.

Cell-theory, as applied to the deve-
lopment of spermatozoids in Torrea
vitrea, 77.

Cell Vegetable, on the structure and
formation of the, by H. Pring-
sheim, 143.

Cell-wall, on the influence of dilute
sulphuric acid on the deposit of
layers of, 78.

Chetoceri, Synopsis of the, 107.

Chetoceros, 105.

Chlorophyll, Mohl on, 162.

Cilia in unicellular plants, F. H.
Wenham on, 157.

Circulation in aqueous plants, James
Western on the, 84.

Circulation in Fungi, 270.

Collodion, Rev. W. Hodgson on the
application to the production of mi-
crometer for the microscope, 240.

Collosphera, 75.

Comparative Anatomy, Rymer Jones’
Manual of; review of, 149.

314

Currey, F., notice by, of Hartig on
the Phytozoa of Antheridia, 51.
“ on the reproductive or-
gans of certain fungi, 192.
Cutting-machine, by Mr. W. S. Gib-
bons, 302,
Cymbella, various new species of, 4-6.
Cystolites, or calcareous concretions
in the Urticacer, &c., H. A. Wed-
dell on, 80.

D.

Defrancia intricata, 179.
Degeneration, Amyloid, on the
course of, by Rudolph Virchow,
135.
3 green pigment, of the
heart, 111.
Dental tissues, on certain conditions
of the, by John Tomes, 97.
Dennis, the Rev. J. P., on the mi-
croscopic structure of bone, 261.
Deposit-layers of the cell-work, on
the influence of dilute sulphuric
acid on the, by Dr. T. Hartig, 78.
Diatomace, on the distribution of,
13.

a J; /C2 Hall, M-D., on
an easy method of viewing certain
of the, 205.

a on the filamentous, long-
horned, by Thomas Brightwell,
105.

ty method of disintegra-
ting, 302.

¥ on new species of Bri-
tish fresh-water, by W. Gregory,
MDinl

ss of deep sea, 305.

Dicladia capreolus, 107.

EK.

Enamel, John Tomes on the develop-
ment of the, 213.
35 on the structure of, 103.
Encystidium, 76.

F.

Farrella gigantea, 93.

“ Finder,” Mr. Amyot’s, 243.

Finders and Indicators, T. E. Amyot
on, 153.

Fly’s foot, remarks on the, by J.
Hepworth, 89.

Foraminifera, Researches on the, by
W. B. Carpenter, 171.

4 Notes on British, by

J. Gwyn Jeffreys, 173.

INDEX TO JOURNAL.

Fungi, Fred. Currey on the repro-
ductive organs of certain, 192.
» circulation in, 270.
»» Microscopic, in drinking-
water, 271.

G.

Gibbons, W. S., on microscopic inves-
tigation, 209.

Glaisher, James, on the snow and
camphor-crystals, 203.

Gomphonema, new species of, 12, 13.

Goniothecium, 106.

Gorham, John, on the magnifying
power of short spaces, 27.

Gosse, P. H., Handbook to the Ma-
rine Aquarium, 147.

F Manual of Marine Zoo-
logy, review of, 147.

53 on the _ structure,
functions, and homology of the
manducatory organs in the Class
Rotifera, 169.

Green pigment degeneration of the
heart, Dr. Thudichum on, 111.

Gregory, W., M.D., on a new species
of Diatomacez, 1.

H.

Haliomma, 75.

Hall, J. C., M.D., on an easy method
of viewing certain of the diato-
mace, 205.

Hartig, Dr. T., on the influence of
dilute sulphuric acid on the deposit
layers of the cell-wall, 78.

* on the Phytozoa of
Antheridia, 51.

Henfrey, A., on the structure and
formation of starch grains, 162.

Hepworth, J., on the practical appli-
cation of the microscope, 109.

~ remarks on the fly’s
foot, 89.

Hibberd, Shirley, review of ‘Homes
of Taste,’ by, 298.

Highley, Samuel, contributions to
micro-mineralogy, 220,

55 micro-mineralo-
gical researches, 277.

| Histology, pathological, by Carl Wedl,

review of translation of, 225.
Hodgson, Rev. W., on the application
of collodion to the production of
micrometers for the microscope,
240.
ae on defining the
position and measuring the magni-
tude of microscopic objects, 209.

INDEX TO JOURNAL.

Hunt, G., on the proboscis of the
Blow-fly, 238.

Huxley, T. H., observations on the
structure of Appendicularia fla-
bellum, 81.

if on the reproductive

organs of the cheilostome Polyzoa,

191.

Br on the systematic po-

sition of Sagitta, 26.

a on Thalassicolla, 72.

ir.

Indicator, universal, for microscopes,
by J. W. Bailey, 55.

J.

Jackson, George, on micrometers and
micrometry, 241.

Jeffreys, J. Gwyn. on Foraminifera,
173.

Jones, Rymer, manual of comparative
anatomy, review of, 149.

L.

Lankester, Dr., on Fungi in drinking
water, 270

Lardner, Dr. D., review of the Mi-
croscope by, 298.

Lawson, G. on the microscopical struc-
ture of the Victoria regia, 163.

Lepralia, new species of, 177, 178.

Lyme Regis River-bed, deposit of,
261.

M.

Mammifers, existence of, demon-
strated from the microscopic struc-
ture of a bone, 261.

Marine aquarium, handbook to the,
by P. H. Gosse, review of, 147.

Mariue Zoology, a manual of, by P. H.
Gosse, review of, 147.

Maschke, O., on the starch grain, 85.

Membrauipora, new species of, 176.

Midge, on the foot of the, 89.

Micographie Dictionary, review of
the, 227.

Micrometers applied to microscopes,
W. Robertson on, 153.

Micrometers and Micrometry, George
Jackson on, 241,

Micro-mineralogy, Samuel Highley’s
contributions to, 220.

Micro-mineralogical researches
Mr. 8. Highley, 277.

Microscope and its revelations, by W.
B. Carpenter, review of the, 231.

by

315

Microscope, on a new form of, by R.
Warington, 90.

a on the practical applica-
tion of the, by J. Hepworth, 109.

Microscopical Society, proceedings of
the, 90, 168, 244, 307.

Microscopic objects, Rev. W. Hodg-
son, on defining the position and
measuring the magnitude of, 209.

Mohl, H., on chlorophyll, T62--—

Miiller, Professor, on Spherozoum,
(Thalassicolla,) Noctiluca, and the
Polycystine, 72.

Myriocephalum botryosporum, 193.

N.

Navicula, new species of, 6-8.
Nocticula, Professor Miiller on, 72.

A

Odogonium, micropyle of the spo-
rangia in, 131.

Omphalotheca hispida, 107.

Orbitolites, W. B. Carpenter, mono-
graph of the genus, 171.

PB.

Pathological Society, transactions of,
2935.

Phytozoa of Antheridia, Hartig on
the, by F. Currey, 51.

Pinnularia, new species of, 8-10.

4 borealis, note on, by J.,
241,

Poiarising of silica, 303.

Polycystine, Professor Miller on the,
72.

Polygastrica, James Samuelson, on
the stomachs of the, 165.

Polysiphonia fastigiuta, on the struc-

- ture of the frond of, 87.

Polyzoa, cheilostome, T. H. Huxley,
on the reproductive organs of the,
191.

» from Mazatlan, description
of new species of, | 76.

Pringsheim, H.. on the structure and

formation of the vegetable cell, 143.
3 M., on the impregnation
and germination of Algwz, 63, 124.

Proceedings of. the Microscopical

Society, 90, 168, 244, 307.

Q.

Quatrefages, M. de, on the develop-
ment of spermatozoid in Torrea
vitrea, 76.

316

R.

Researches on the structure and form-
ation of the vegetable cell, by Dr.
H. Pringsheim, 143.

River-bed, deposit Lyme Regis, 261.

Robertson, W., on micrometers ap-
plied to microscopes, 153.

Rotifera, P. H. Gosse, on the man-
ducatory organs of the, 169.

Royal Society, proceedings of the, 169.

SS)

Sagitta bipunctata, G. Busk, on the
structure and relations of, 14.

, 1. H. Huxley on the sys-
tematic position of, 26.
,, Various species of, 25-26.

Samuelson, James, on the stomachs
of the Polygastrica, 165.

Sap-cireulation of Plants, notes and
observations on, by F. H. Wenham,
44,

Sea-deep, diatomacee of, 305.

Short spaces, on the magnifying
powers of, by John Gorham, 27.

Silica, polarising of, 303.

Snow crystals, James Glaisher on the
similarity of forms observed be-
tween, and those of camphor, 203,

a5 Joseph Spencer on the
similarity of forms of, with those
of camphor, 201.

Society, Microscopical, proceedings
of, 90, 168, 244, 307.

Speerschneider’s, Dr. T., collection of
microscopical preparations, 89.

Spencer, Joseph, on the similarity of
forms between snow crystals and
those of camphor, 201.

Spermatazoids, on the development
of, in Torrea vitrea, 76.

Sphacelaria tribuloids, 128.

Spheria eryptosporti, 199.

Spherozoum (Thalassicolla), Nocti-
luca, and the Polycystine, Professor
Miiller on, 72.

Starch grains, A. Henfrey on the
structure and formation of, 162.

35 O. Maschke on the, 85.

Stauroneis, new species of. 10.

Steam bath for preparing objects, 299.

Steganosporium cellulosum, 197.

Surirella tenera, 10.

Syndendrium diadema, 107.

INDEX TO JOURNAL.

Av

Thalassicolla (Huxley) Professor
Miiller on, 72.

Thudichum, Dr., on green pigment-
degeneration of the heart, 111.

Tomes, John, on certain conditions
of the dental tissues, 97.

- on the development of
the enamel, 213.

as on the structure of the
enamel, 103.

Torrea vitrea, on the development of
spermatozoids in, by M. de Qua-
trefages, 76.

Transactions of Pathological Society,
293.

Triceratium, new species of, 272.

U.
Urticacez on the crystolites in the, 80.
Ws

Victoria regia, on the microcospical
structure of the, by G. Lawson, 163.

Virchow, R., on the course of the
amyloid degeneration, 135.

Ww.

Warington, R., on a new form of
microscope, 90.

Weddell, H. A., on the erystolites or
calcareous concretions in the Urti-
cacee, 80.

Wedl, C. pathological histology, re-
view of translation of, 225.

Wenham, F. H., on the aperture of
object glasses, 259.

zs on cilia in unicel-

lular plants, 157.

3 reply to Professor

Bailey on the aperture of object

glasses, 85.

99 on the sap-circula-
tion of plants, 44.

Western, James, on the circulation in
aqueous plants, 84.

Weston, I., on Actinophrys Sol, 116.

Z.

Zoophytology, 93, 176, 308.

LONDON: PRINTED BY W- CLOWES AND SONS, STAMFCRD STREET.

TRANSACTIONS

MICROSCOPICAL SOCIETY

EON DON.

NEW SERIES.

VOLUME IV.
LONDON:

JOHN CHURCHILL, NEW BURLINGTON STREET.
1856.

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INDEX TO TRANSACTIONS.

VOLUME IV.

A.
Address of the President of the

Microscopical Society, 17.
Alge new to Britain, 49,

B.

Beale, Lionel, M.B., on a simple
form of portable microscope, with
lever adjustment, 13.

C.
Cell, vegetable, Mr. Wenham on, 60.

D.

Diatomaceous sand of Glenshira, 35.

G.

Illuminating opaque objects, Mr.

Wenham, on, 55,

M.

_ Microscope, portable, on a simple

form, with lever adjustment.
Lionel Beale, M.B., 13.

By

| Microscopical Society, Address of the

|
}
|
|

President, 17.

3 5 Report of the
Sixteenth Annual Meeting of
the, 15.

R.
Report of the Sixteenth Annual
Meeting of the Microscopical So-
ciety, 15.

S.

| Sand, diatomaceous, of Glenshira, 35.

Greville, Dr. R. K., drawings of dia- |
| Vegetable cell, on the formation and

tomacee, 35.

Gregory, Dr. W., on
tertiary diatomaceous
Glenshira, 35.

Glenshira, diatomaceous sand of, 35.

the post-
sand of

H.
Henfrey, Arthur, Notes on

fresh-water Confervoid Algw, new
to Britain, 49.

some |

V.

development of the; By F. H.
Wenham, 1.

Wie

Wenham, F. H., on the formation
and development of the vegetable
cell, 1.

ae = on a method of
illuminating opaque objects, 55.

99 - on the vegetable

cell, 60.

LONDON : PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS.

TRANSACTIONS

OF THE

MICROSCOPICAL SOCIETY

OF

LONDON.

On the Formation and DEVELOPMENT of the VEGETABLE CELL.
By F. H. Wenuam.

(Read November 28th, 1855.)

Tue favourable manner in which my paper on ‘Sap Circula-
tion,’ published in the Jast ‘ Journal of Microscopic Science,’
has been received, by some of the most eminent members of
this Society, has encouraged me to bring directly before the
present meeting the result of investigations on the origin and
first formation of the Vegetable Cell.

As I have admitted that I take up the microscope only
occasionally, as a means of recreation rather than a special
study, it may probably appear great presumption in one, com-
paratively unpractised, to make a statement of investigations
that stand in opposition to the opinion of the distinguished
observers who have written upon this self-same subject, after
many years of observation, aided by an intimate knowledge
of the researches of others in a similar department. I must
state, therefore, that I write with due submission, and in the
hope that some of the facts mentioned herein may contribute
towards the promotion of science, if only by directing atten-
tion towards a field of investigation, which, in my opinion, is
yet comparatively unexplored.

Feeling that many who take up the study of a particular
department of physiological science for the first time will
agree with me, I cannot refrain from protesting against the
excessive predilection that most professed writers exhibit, in
applying technical phraseology to a new branch of science
even in the earliest stages of discovery. From this mistaken
display of scientific pedantry, the uninitiated are probably at
first quite unable to comprehend the matter; and worse than
this, an inappropriate name is frequently applied to a circum-
stance or imaginary substance, having a doubtful, or at least

VOL. IV. b

2 WenuaM, on the Vegetable Cell.

not a very general existence, and this name is continued
throughout the whole series of subjects to which the science
relates, often giving rise to a maze of hypothesis. I make
the remark because the physiology of the vegetable cell is an
example of this, Let any one desirous of knowing in what
manner the cell is said to be first formed, take up the ela-
borate works on the subject by the continental writers, he will
find it there stated that an universal and necessary condition
of the existence of the cell is the first formation of a central
nucleus, termed the ‘cytoblast.” Around this is next
formed a membrane which eventually encloses the cell con-
tents, this is named the “primordial utricle,” and by the
division and duplication of this, successive cells are supposed
to be accumulated.

The primordial utricle is'a necessary condition in the
anatomy of some unicellular plants, such as the Desmidiee and
Alga, for, in these instances, the folding inwards of this im-
portant membrane causes a constriction of the contents of each
cell, and a reproduction and multiplication by self-division ;
but the same analogy cannot be extended throughout the vege-
table kingdom, in those cases where a system of cells haye a
mutual dependence upon each other. In unicellular plants
each cell is one in its most complicated condition, and
capable of continuing its existence as a separate plant, inde-
pendently of others, and is therefore provided with special
organs requisite for this peculiar mode of growth.

Those microscopists who, like myself, experience the most
fervent delight in reading a page directly from the book of
nature, may resort to their microscopes again and again in the
hope of witnessing the first creation of the vegetable cell, in
relation to the acting conditions of the cytoblast and pri-
mordial utricle. The search may be carried from tree, shrub,
flowers, or fruit, and be alike in vain. No direct ocular
evidence will be obtained of the existence of this nucleus and
membrane, and the attempt is abandoned at last, perhaps not
without some feelings of humiliation at the supposed un-
skilful manipulation, that failed to discover facts, believed to
have been firmly established.

Before proceeding to describe the formation of the vege-
table cell, I must premise that I am fully aware that the
interests of science are not to be promoted by controversy
based entirely upon mere hypothesis; I have, therefore, care-
fully avoided this. The illustrations were drawn directly
with the camera lucida in exact conformity with the originals,
and I have confined myself entirely to what I have seen; but
this course will not perhaps justify the assumption of a dog-

»

Wennay, on the Vegetable Cell. 3

matical position, for in microscopical investigation there is
some risk in even trusting solely to the evidence of eyesight,
and it frequently happens that a series of real facts may be so
arranged as to form the basis of a false theory.

In the last number of the ‘ Quarterly Journal of Microscopical
Science,’ I described an instance wherein I had observed the
growth and thickening of a cell wall to be caused by the de-
posit of a mass of active corpuscles, the so-called protoplasm.*
It is from this mysterious vital substance that all the cell tis-
sues of the vegetable world are built! The starch and chlo-
rophyll contained in the cell cavities, are also seen to derive
their increase of bulk by the deposit of the same material. If
any portion of a vegetable tissue (particularly if cousisting of
a group of young cells) be placed in the compressor with a
very small quantity of water, and examined under a high power,
by applying sufficient force the mass will burst, and as the
protoplasm flows forth the following peculiarities may be
observed. It is not soluble in water, but only diffuses itself
therein; it is in all cases materially composed of active
particles, the size of which differ extremely in various
plants ; in some of the lower Cryptogamia, the particles con-
stituting the protoplasm are exceedingly minute, but with
a large aperture and good illumination the whole is still
seen to be chiefly composed of an assemblage of active
molecules.

Protoplasm, when flowing from the living plant into the
surrounding water, exbibits a remarkable tendency to separate
itself into cavities and ramifications, which speedily acquire
some degree of consistency, apparently from the formation of
a membrane, by the partial coagulation of the external
portion exposed to water. When the ramifications become so
much attenuated, as only to allow the passage of a few active
particles at a time, the lateral vibrations of these become
restricted, and they travel some distance either backwards or
forwards, in a manner very much resembling a single cur-
rent of sap in the living vegetable cell. At the point where
the cells have been ruptured, the protoplasm will sometimes
form a membraneous tube, through which the discharge takes
place.

Protoplasm exists in a dormant state of vitality in seeds
and dried roots, and many pollen granules appear to be simple
vesicles filled with this substance, the molecules being more
decidedly marked for partial drying. When a pollen grain

* The substance termed sarcode, composing the vital tissue of some of
the lowest orders of animals (such as Hydra viridis), bears a remarkable
resemblance, in some respects, to vegetable protoplasm.

b 2

4 Wennam, on the Vegetable Cell.

has been deposited in the plant ovule, the occurrence of a
cyclosis or circulation is said to have been discovered, passing
through the channel of communication that is formed between
the granule and embryo sac. This I have not yet witnessed.
Whether the protoplasm contained in vegetable cells is
endowed with the property of fertilization, | am not able to
affirm, unless the following circumstance can be taken as
evidence of the fact. During the conjugation of some of the
Alga and Desmidiee, the contents of two cells are expelled,
and first unite in the form of a shapeless mass; the accom-
panying protoplasm is now seen to extricate itself from inter-
vening particles, and envelope the whole of the ejected
endochrome with a gelatinous-looking sheath. All irregular
projections are next drawn inwards, and the mass acquires a
spherical or ovoid form. The exterior of the layer of proto-
plasm is then converted into an investing membrane, and
finally a perfect sporangium is the result.

The point that I wish to direct attention to is this. If just
at the time that the combined masses of endochrome are
assuming the spherical shape, the lid of the compressor used
for the observation is repeatedly raised and lowered, so as to
wash away the investing layer of protoplasm, the mass of
endochrome will retain its ragged outline, without alteration,
for many successive days, and a sporangium will not be
eventually formed, thus showing that it is the living proto-
plasm that imparts the principle of vitality to the germ, and
also arranges the cell contents in the proper course of sym-
metry and order.

There are some remarkable movements of corpuscular
activity to be observed in some seeds, mainly due to the
presence of protoplasm. If a very thin slice of horse chest-
nut is moistened with a small quantity of water, and covered
with thin glass, after about one hour’s duration the motion
will be in full force. The whole field of view is filled with
active granules of protoplasm, and also of starch, in all stages
of growth, the most minute of the latter being possessed of
molecular motion. ‘There are some spots in the fluid not to
be distinguished from the surrounding medium, either by
difference of density or any other indication, and which yet
cause a very peculiar action, for when the active particles
approach these places they are whirled rapidly past. Some-
times a molecule will suddenly start forward and shoot
straight across the field of view with considerable velocity,
dashing otbers out of its course. This oftentimes happens
when two have become adherent, and occasionally several
will be linked together in the form of a spirozoid, which

Co. eo

*

Wennam, on the Vegetable Cell. 5

screws its way through the water with a somewhat uniform
speed,*

Having briefly noticed some of the properties of proto-
plasm, I will proceed at once to the main subject of my paper.
I have selected the Anacharis Alsinastrum as one of the
subjects of investigation, chiefly on account of the magnitude
of the vital phenomena, and also because the perfect trans-
parency of the walls of the cells permits their internal move-
ments to be seen without impediment in the earliest stages of
growth, the action continuing under considerable mutilation

* Fearing that I am digressing too far from the direct title of this
communication, I append this note, submitting some further remarks on
corpuscular motion. When a single active molecule is in an isolated
position, its vibrations occur spontaneously and at random in all directions ;
but when a number are combined together in a line of narrow compass, if
they have a tendency to mutual entanglement or adherence, as in the
instance of the component gelatinous corpuscles of protoplasm, the longi-
tudinal vibrations are restricted, and the atoms are compelled to move
from side to side, or transversely. This occasions a waving or serpentine
movement of the thread-like current, which causes the whole to travel in
a straightforward direction ; thus accounting for the circulation in the
vegetable cell. In some plant cells a thread of protoplasm, consisting of
a single line of particles, displays in its appearance such a remarkable
analogy to a single cilium, that I am inclined to consider the seminal fila-
ment, attached to some vegetable spores, as a simple line of conjoined
active corpuscles, the lateral vibrations of which cause the undulating and
progressive motions of the filament.

I cannot at present call to mind any instance wherein a strictly vegetable
cilium is possessed of a permanent existence. After its first temporary
office is fulfilled, as an organ of locomotion, for propelling the vital spore
to another locality, it speedily becomes disorganised, and disappears.

On the other hand, the animal cilium, used either as a prehensile or
motile organ, is far more complicated. It is endowed with permanency,
and capable of renewal in cases of injury.

As a matter of conjecture, I offer a remark on those minute bodies
termed spizilla, or spirozoids, which are found in decomposing vegetable
and animal solutions. They are sometimes so irregular in shape, length,
and bulk, that 1 suppose them to be merely associated particles of organic
matter linked together. If the component atoms are in a state of mole-
cular activity, the progressive undulations of the filament will cause the
helix to turn on its axis, and, in consequence, these corkscrew-like forms
advance through the fluid by rotation.

In the paper contributed to the last number of this Journal by Mr.
Busk, we are informed of the fact, that associated vital corpuscles in the
living animal possess the same tendency to travel in a direct forward
course as in the vegetable cell:—page 22: “ A remarkable circumstance
observable in the spermatic cavities of Sagitta, is the continual cyclosis
performed by their contents. These will be seen constantly ascending on
the outer, and descending on the internal wall, or septum.” I have some-
times seen a cyclosis in the Motifera, in an organ which I presume to be
a spermatic vesicle; but this discovery, in a being apparently so highly
organised as the Sagitta bipunctata, is an important advance into the
mysteries of animal creation.

6 Wennam, on the Vegetable Cell.

and distortion of form—a circumstance of particular import-
ance.

On dissecting out the centre of the bud at the extreme end
of a stalk of the Anacharis, a kind of cellular cone will be
found, shown PI. L., at a, fig. 1; 56 are protuberances extend-
ing up the sides of the cone, being the germs of future leaves
in various stages of growth.

In the first for mation of a leaf from the main stem, a small
nodule or protuberance appears, which is entirely filled with
granular protoplasm. A number of cavities next become
disseminated throughout the mass, as represented by fig. 2.
These are formed in the most random and irregular manner, both
as to size and position—small spaces being indiscriminatel
mixed with larger ones of perhaps ten times their bulk, much
resembling the cavities in a slice of bread-crumb. There is
no special means provided for the formation or arrangement
of these spaces, neither does it arise from any species of fer-
mentation, but from the inherent property that protoplasm
possesses of separating itself from its more fluid admixtures,
and forming cavities and thread-like divisions, as chance alone
directs.

At this primitive stage there are no travelling currents of
protoplasm, a feeble corpuscular motion is all that is to be
seen. ‘These cavities are the foundation of the cell formation.
Very minute starch granules make their appearance in some of
them, even at this period, as shown at a, a, fig. 2. This
example was drawn from the Anacharis, but it may be taken
as the representative of the primary cell formation of the
largest portion of the vegetable creation. The first germs of
either leaves, flowers, or stems, alike consisting simply of a
nodule of irregular diversiform cavities, so nearly similar in
shape and arrangement in widely-different species, as scarcely
to exhibit any distinctive features of variety, I have selected
the following plants to exemplify this :—Fig. 3 is a mass of
cells in their first formation, taken from the centre of a bud
of Arabis albida, with rudimentary cavities appearing in the
body of protoplasm at the apex. Fig. 4 is a leaflet from the
same plant, with the cells in a rather more advanced stage,
each cell containing a few minute nuclei, or incipient starch
granules. Fig. 5 is a malformed stellate hair, the base being
filled with protoplasm, which, in the upper portion, exhibits a
tendency to divide itself into cavities and cells. Fig. 6 is a
leaflet of Reseda, the apex having burst under the action of
the compressor, and the protoplasm had exuded into the sur-
rounding water, in the form of a globule, filled with cavities,
shown at a, a. ‘This accident frequently happens, and may

Wewnam, on the Vegetable Cell. 7

readily be mistaken for a mass of primary cell formation
Fig. 7 is the first formation of a linear leaf of the Anethum
Feniculum, bearing much resemblance to fig. 2.

Having shown the analogy between the primitive cell for-
mation of the Anacharis and non-aquatic plants, I will now
trace the cell in its progressive stages of development, referring
from fig. 2, Fig. 8 represents the Anacharis cells in a more
advanced condition. A general longitudinal extension has
taken place throughout the mass, and something like a definite
line of cell formation becomes apparent. The cavities contain
an increased number of starch nuclei, and are now lined with
a distinct wall or membrane, but still, from the thickness of
the intermediate substance, the whole structure resembles a
number of irregular vesicles or bags, imbedded in _proto-
plasm,

If at this period of growth a portion of the leaflet be sub-
jected to the test of alcohol, the cellulose membrane lining
each cavity will separate, and shrink together upon the cell
contents. This has probably been mistaken for the so termed
primordial utricle; but however this may be, it is, in fact,
from first to last, the true cell wall, and is not dissolved or
absorbed in any subsequent state of the cell’s existence. It
thus appears that a bud, instead of starting at first from a
single cell, as some have imagined, derives its origin from the
simultaneous development of a group of some hundreds. The
number of cavities in the primary nodule do not exactly cor-
respond with the number to be contained in the perfect leaf,
for wherever there is an accumulated bulk of protoplasm, a
space is sure to be formed within it subsequently ; new cells
are thus continually in the course of formation.

On considering fig. 2 it will become evident that if an
uniform distension of the mass should take place, the great
disproportion in the bulk of adjoining cavities would create a
system of cells, of such monstrous difference in size and
length, as to set all symmetry at defiance (well illustrated by
the extension of an india-rubber model). The manner in
which this difficulty is obviated, and regularity obtained at
last, is both simple and beautiful. Fig. 9 represents a series
of cells ina more advanced stage of growth. The walls are
yet soft, and much exceed their destined and final limits of
thickness. At this period cyclosis may be distinctly seen in
each cell, all of which now contain protoplasm within their
walls. In those cells that are exceedingly elongated, and dis-
proportionate in size, the protoplasm accumulates in the
middle, and forms a thick septum across, as shown at a, a, a,
thus dividing the cell into two. On both sides of the septum

8 Wenuam, on the Vegetable Cell.

a thin membrane is next formed, which constitutes the end
wall of the two cells. The two membranes gradually approxi-
mate towards each other, and the intervening protoplasm
disappears.

In instances where the cell is of excessive length, a larger
mass of protoplasm accumulates midway, in the centre of
which a cavity makes its appearance, as at a, fig. 10; this
enlarges, and becomes lined with a membrane, and thus di-
yides the original cell space into three parts.

A tissue of cells, in the stage of development represented
by fig. 9 is nearly colourless ; it is about this period that it
begins to emerge out of its dark location, so far as to give the
first indications of the chemical action of light in causing the
deposit of chlorophyll instead of starch. The minute granules
of starch, previously scattered throughout the cells, serve for
the nuclei of the chlorophyll granules. At first they are enve-
loped in a delicate green coating, which becomes thicker, and
more decided in colour, as the cell approaches further into the
light. These incipient chlorophyll granules are now frequently
carried about in the currents of protoplasm circulating in the
cells at this time. A single atom of starch is sufficient for
the nucleus of a chlorophyll granule, but sometimes the green
coating is deposited simultaneously upon a group of several
together.

Fig. 11 represents the cells of a leaf of Anacharis in its
latest stage of vital existence. The cell walls having now
attained their utmost degree of thinness and consistency, the
entire leaf acquires a yellow tinge, from the altered colour of
the shrunken and partly dissolved chlorophyll granules (hence
termed “ xanthophyll’), which now so far disappear, that some
cells contain only two or three, much disintegrated. At this
period the leaf cells, though apparently in their first stage of
decay, are probably performing their most important functions,
by affording nutriment to the growing plant, by the dissolution
of their contents. In the specimen here drawn a rapid cur-
rent of protoplasm was trayersing the interior of each cell.
This motion is perhaps quite as necessary for the solution of
the cell contents as for their formation by successive deposits ;
in fact, the phenomena of cell circulation are oftentimes best
seen at this stage.

I have omitted to mention that indications of a strong en-
dosmotic force are perceptible throughout the entire course of
cell formation. The cavities spontaneously formed in an
exuded mass of protoplasm sometimes burst from the accumu-
lation of fluid in their interior ; many unicellular plants, after
being partly dried, will also burst on being again subjected to

Wenuam, on the Vegetable Cell. 9

moisture, from the infiltration of water into their cells. It is
this same force which is chiefly instrumental in causing the
distention of the detached vesicle or bag, of which each cell
primarily consists, till at last contiguous walls become united
throughout the structure. In some instances the force is not
sufficient to cause the complete distention and union at the
corners, consequently the leaf tissues of many plants are cha-
racterized by little angular spaces, occupying the point of
union between the confluent walls of neighbouring cells.

It now remains to be asked, if the first origin of all parts of
the vegetable structure consist merely of a protruding nodule
of protoplasm, containing numerous cavities in size and posi-
tion most irregular, what is it that determines whether this
shall form either a stem, flower, or leaf at last, the first forma-
tion being alike for each? The question is a difficult one to
answer in all its details, but it may be stated with certainty
that the primitive mass possesses no inherent power of its own,
in either shape or substance, to arrange its destined form of
growth. This is dependant entirely upon the influence of the
adjoining, and more perfectly developed portions of the plant.
In the case of a leaf, the soft cellular mass, while yet growing
in the bud, is moulded to something like its proper form by
the pressure of other leaflets, and when the cells of the embryo
leaf have acquired some degree of consistency, a single spiral
duct * is seen to grow out of the parent stem, forcing its way
as an axis through the soft assemblage of cells. Others quickly
follow, and lateral ramifications extend themselves as form
requires, In the case of a leaf, all this may be very readily
observed, but the formation of a flower-bud involves far more
complicated conditions, with the whole details of which I do
not profess to be acquainted. Fig. 12 will, however, serve as
an illustration; it is a group of embryo fiowers, taken from
the Arabis albida, during the month of October (the fully
developed blossom not appearing until the ensuing spring):
a is a simple protuberance, filled with protoplasm, in its early
stage of cell formation; 4 is a flower-bud, at a more ad-
vanced period of growth, the centre being permeated by
several spiral ducts and vessels. In the stages e, d, and e the
ducts and vessels are still to be discerned, but very much in-
creased in number and complexity; f and g exhibit all the
rudiments of the perfect flower, being apparently made up of

* It has not been explained very clearly how these vessels are formed.
By frequently observing their growing end among a mass of young cells,
I have imagined that I have detected a disc-shaped cell at the extremity,
by the successive formation and subsequent perforation of which the spiral
duct is formed; but the first growth is so indistinct and ill-defined, that
I cannot at present affirm it with certainty.

10 Wennam, on the Vegetable Cell.

thickened and gelatinous-looking masses of cells; / are cell
prolongations, or the successive rudiments of stellate hairs.

I may remark, in conclusion, that I am aware that some of
the facts relating to vegetable growth herein mentioned are
not new, but information on this subject exists in so scattered
a form that there is some difficulty in making special references.

Addendum.

In order that there may be no misapprehension of my
views, with respect to cellular creation, I append the following
summary of the succeeding stages :—

The first appearance of the formation of vegetable cells is
a simple protuberance filled with protoplasm, alike throughout
in substance. This is enclosed by a skin or membrane, the
origin of the future leaf cuticle, but which, I presume, at this
early period, would be termed the “ periplast.’ A number
of irregular cavities (vacuoles), filled with watery cell sap,
now make their appearance. ‘These are simply formed by
the separation and agglutination of the viscous protoplasm.
A thin lining membrane is next developed in the interior of
each cavity; this does not become detached at any after
period, but is, in fact, the inner stratum of the future cell-
wall. The membrane is thickened into a true cell-wall by the
direct transmutation into cellulose of the protoplasm existing
between, and ezterior to the cell cavities.

It is not until the cell-wall has advanced to a well-marked
degree of development that any protoplasm is generated within
the cell. This now rapidly makes its appearance, and spreads
itself within the cell-wall. Hence arises the question whether
this, when in the form of an internal layer, is explicitly un-
derstood if termed the “primordial utricle?” In this case
primordial is certainly inapplicable, because protoplasm does
not make its appearance in the cell cavity before it is some-
what advanced in growth, and sometimes is not even seen,
until subsequently to the formation of minute starch granules
adherent to the cell-walls.

By the application of a reagent, the protoplasmic layer,
from being extremely prone to coagulation, can be made to
contract like a membrane upon the cell contents, but I ques-
tion whether the term membrane, or utricle, is to be properly
applied to a motile but viscous fluid, which at times will run
together in patches and clots, and leave large portions of the
cell-wall bare. There is perhaps no reason against the pro-
priety of the term when applied to some unicellular plants, in
which the appearance and uses of such a membrane are so
distinctly to be observed.

TRANSACTIONS OF MICROSCOPICAL SOCIETY.

DESCRIPTION OF PLATE I., Vou. IV.
Illustrating Mr. Wenham’s Paper on the Vegetable Cell.
Fig.
1.—End of stalk of Anacharis alsinastrum. 6, b. Germs of future leaves.
2.—Primitive cell-formation of leaf of Anacharis.

3.—Primitive cell-formation of Arabis albida, with the rudiments of cells
appearing at the apex.

4,—Leaflet of Arabis, with cells in a more advanced stage.

5.—Malformed stellate hair with the protoplasm at the apex, showing
a tendency to cell-formation.

6.—Leaflet of Reseda burst at the apex. The exuded mass of protoplasm
having become filled with cavities.

7.—Primitive cell-formation of leaf of Anethum Feeniculum.
8.—Cells of Anacharis in succeeding stage to Fig. 2.

9.—Cells of Anacharis in more advanced stage. a. a. Septa of protoplasm
dividing cells too much elongated into two parts.

10.—Cell excessively elongated with an intermediate mass of protoplasm,
a, Cavity formed in protoplasm which expands and divides the
original cell-space into three parts.

11.—Cells of Anacharis in latest stage of growth.

12.—Group of embryo flowers of Arabis albida. a. b. c. d.e. f. g. Succes-
sive stages of development. h, Cell prolongations or rudiments of
stellate hairs.

1, [
TO
LVF,
=

Soe XL

Ue

: Nb,

J

A Simple Form of Portaste Microscope, with Lever
ApsUSTMENT, which may be adapted to several different pur-
poses. By Litonet Beare, M.B., Professor of Physiology
and General and Morbid Anatomy in King’s College,
London.

Tue Microscope which I wish to bring under the notice of
the Society, seems to me to possess some advantages over
those in ordinary use in simplicity of construction, in the
number of uses to which it may be applied, and in price.
The accompanying outline diagrams show the general ar-
rangement of the instrument. The telescope stem, a, and
horizontal arm, b, upon which the body, c, is fixed by the aid
of a hinge-joint, e, are made of brass tubes, about an inch in
diameter. Upon the outside of the stem the stage, f, and
mirror, g, are made to slide. The lower part of the stem
slides in a tube, h, provided with a clamp screw, 2, so that
the whole instrument may be arranged in the erect posture at
any convenient height, Fig. 1, Pl. IL. If required, the mirror
can be fixed upon the lowest part of the stem beneath the tripod
at k. The tripod stand may be made of cast iron or of brass,
and each leg attached with a hinge-joint, which increases its
portability. The horizontal bar is prevented from turning
round by a ridge, 7, which is fixed upon its lower surface, and
which slides in a groove in a piece of tube attached to the
upright by a hinge-joint, m. The coarse adjustment consists
of a knee-lever, m, and in this way a very smooth and steady
movement of three inches in extent is obtained. The tube in
which the body slides should be longer than that in the instru-
ment exhibited this evening. For the adaptation and manu-
facture of this lever adjustment [ am indebted to Mr. Becker,
Philosophical Instrument Maker, of Newman-street. <A fine
adjustment may be attached in the usual position, just above
the object glass, 0. Upon the front of the body, in its upper
part, is placed a small piece of brass, with a number of holes,
p, in which a small brass pin may be inserted, so that the
object-glass may be brought as close to the object as may be
desired, and at the same time without any danger of its being
forced down upon the object, or through the glass slide
placed upon the stage.

Fig. 1 shows the ‘instrument arranged in the erect posture,
Fig. 2 i in a slanting direction. The horizontal arm, 0, in this
position takes the place of the upright stem. Fig 3 repre-
sents the microscope arranged for making minute dissections,
a small pin, 7, prevents the horizontal har from falling too

VOL. LV. c

14 BEALE, on a simple form of Portable Microscope.

low. In fig. 4 the telescope tube is drawn out, and the in-
strument arranged for examining living animals, &c., in a
vivarium.

The various portions of the microscope are readily sepa-
rated from each other, and can be packed in a small case.
The weight of the entire instrument, with case, &c., will
probably not be more than six pounds, Mr. Matthews, of
Portugal-street, Lincoln’s Inn, thinks that this microscope,
without powers, can be well made for five pounds, or even
less. There is some vibration in the body of the instrument
which I have in use, but the lever movement appears likely
to answer well for all powers below half an inch; the motion
is even smoother than would be supposed. Several slight
alterations in the mechanical parts of the instrument have
been suggested, and will doubtless add to its efficiency. As
a travelling microscope, especially for sea-side work, this
arrangement will I think be found very useful, and is not likely
to get out of repair,

‘ee iaD
REPORT

OF
THE SIXTEENTH ANNUAL MEETING

OF THE

MICROSCOPICAL SOCIETY.

Tue Meeting was held February 27th, 1856,—Dr. Carpenter,
President, in the Chair. The Assistant Secretary read the
following Reports :-—

According to annual custom, the Council have to make the
following Report on the state and progress of the Society
during the past year.

The number of Members at the last Anniversary, was 221,
including 6 Associates and Honorary Members, Since that
time there have been elected 32, making a total of 253. This
number must, however, be reduced by 3 deceased and 9
resigned, making a final total of 241; still showing an
increase of 20 upon the number at the last Anniversary.
Many new works and objects have been added to the Library
and Collections of the Society. There are also in the posses-
sion of the Society various drawings and diagrams relating
chiefly to papers read at the Meetings, together with copies
of the several parts of the Transactions and of the Journal.
The state of the finances of the Society will be shown by the
following Report of the Auditors, from which it appears that
there isa balance in the hands of the Treasurer of 37/1. 14s. 4d.

The election of Officers took place, when the following
gentlemen were elected :—

Officers and Council.

President . . . . Geo. Suapsort, Esq.
Treasurer: 62. NU BE Win, Eee.
Secretary . . . . J. QUEKETT, Esq.

Four new Members of Council.
Dr. LAnKEsTER.
F. S. C. Roper, Esq.
R. J. Farrants, Esq.
Antonio Brapy, Esq.

In the place of
G. C. Hanprorp, Esq.
R. Hopeson, Esq.
Rev. J. B. READE.
F. Srmonps, Esq.
who retire. e2

Sixteenth Report of the Microscopical Society.

16

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Address of the PResivEnv.

GENTLEMEN,—The circumstances under which our Society
now meets, bear so close a resemblance to those which ex-
isted at its last Anniversary, that we must look upon them, I
think, as representing, not a transient condition which it may
be left to time to modify, but a persistent state which has
grown to be a part of our existing constitution. I think it
well, therefore, to place before you, in the best manner I am
able, such an honest view of our position as may bring out
our weak as well as our strong points, our deficiencies as well
as our advantages; and may thus at once suggest remedies
for the former, and lead to the still further development of
the latter.

Our Report is again most satisfactory in regard to the
financial position of the Society. The number of members
still continues on the increase, no fewer than thirty-two new
members having been elected, whilst we have lost only twelve
by death or withdrawal. Our funds have consequently been
adequate, not only to supply every member with a copy of
the ‘ Quarterly Journal,’ but also to furnish tea for our meet-
ings; and we have also been able to meet without inconyve-
nience an unexpected demand for an arrear of twelve guineas
due to the Ray Society.

Our meetings, also, have been almost uniformly well
attended ; and great benefit has doubtless resulted from the
intercommunication which they have promoted between so
many who are interested in the same pursuit.

We are far, however, from having similar cause for satis-
faction, in regard to the number or the importance of the
papers brought before us. The dearth which I last year
hoped might be temporary, has increased rather than di-
minished ; and our meetings would have been without any-
thing to occupy them, on several occasions, if means had not
been extemporaneously found for supplying the deficiency,
Our Transactions for the last year contain but two papers and
one short notice; and these, with a paper which it was not
thought desirable to include in them, and with the exhibition
of Mr. Warrington’s and of Dr. Beale’s new forms of micro-
scope, constitute the whole of the regular business which has
come before us.

Now I cannot but regard the continuance of this state of
things as likely to be most prejudicial to the interests of the
Society. It would be unreasonable to expect that the attend-
ance at our meetings should keep up, if there be no adequate

18 Address of the PresipENT.

prospect of materials for their occupation. That which should
be but a subordinate inducement to membership of the So-
ciety, the title to receive its publications, seems now to have
become the principal attraction ; every member, through the
arrangement which we have been enabled to make with the
proprietors of the ‘Microscopical Journal,’ haying nearly
three-fourths of his subscription returned to him in this form,
But this arrangement may be determined at any time ; since
it merely exists so long as it shall be found to work adyan-
tageously for both parties. If the proprietors of the Journal
should have reason to think that the increase in the number
of our members causes a diminution in the number of their
subscribers, they will probably not consider its continuance to
be for their interest; whilst, on the other hand, if it should
appear that the support which we give to the Journal, so far
from promoting our welfare as a Society, has an indirect
tendency to weaken us, that support we might feel it desirable
to withdraw.

I cannot but consider that both the status of the Society as
a scientific body, which must depend upon the goodness and
quantity of the work it does, and the maintenance of its attrac-
tiveness and efficiency as a centre of union to those engaged in
microscopic research, necessitate the taking of some steps to
supply a deficiency which has now become unfortunately but
too apparent; and the first and most obvious of these steps
consists in the inquiry into its causes. Of these, I shall only
specify what occur to myself; others will doubtless be sup-
plied by such as have a more extended acquaintance than I
possess with the individual members of our Society.

In the first place, 1 am disposed to think that the facility of
publication now afforded by the ‘ Microscopical Journal,’ has
had no inconsiderable influence in diminishing the number of
papers sent to the Society.

Formerly our Transactions constituted the only medium
through which a microscopist could readily make public,
with the requisite illustrations, such results of his inquiries as
might scarcely possess the dignity or completeness required
for presentation to the Royal or Linnean Societies. But the
Journal now opens its pages freely to all, whether Members
of this Society or not; its editors readily admitting every
creditable paper, and liberally furnishing the requisite illus-
trations. Now as our Transactions are published in a form
so precisely similar to that of the Journal, as only to be
distinguishable by the numbering of the pages, few authors
would much care whether their contributions appear in
one part of the Number or the other. And yet there is,

Address of the PreswEnvT. 19

or there might be, a considerable difference in the credit
attaching to these two appearances respectively. For the
editors of the Journal (having to fill a certain number of
pages every quarter) can scarcely be expected to feel that
responsibility as to the quality of the papers they insert,
which lies upon the Council of our Society, which is charged
with admitting into its Transactions only such communi-
cations as they may deem possessed of a certain scientific
value. As the case at present stands, I cannot but believe
that the want of due appreciation of the superior credit of our
Transactions, and a feeling of indisposition on the part of
authors to subject their communications to the double ordeal
of a public discussion and of a privately-considered verdict,
have kept, and will continue to keep, many valuable papers
from being brought before the Society.

Now if such be really one of the causes of deficiency, the
next question is, how can it be remedied? The remedy does
not seem to me to be easy, so long as the existing union
between the Transactions and the Journal shall continue ;
and this union is attended with so much advantage to our
Members, that I cannot advise its discontinuance. But it
has occurred to me that a more marked difference might be
advantageously made between our Transactions and the
Journal, by adopting a different style for the former,—a some-
what larger type, for example, or a more open page,—which
should in some degree mark the superior status which I
claim for them. The remedy lies essentially, however, with
the Members themselves; who ought, I think, to feel under
an obligation to promote the interests of the Society, by
sending their communications to it, rather than forward them
direct to the Journal: and though we can scarcely exert any
compulsion in such a matter, yet | would have the latter pro-
ceeding discouraged, and the former encouraged, by the potent
voice of public opinion. Further, if we can, by such a dis-
tinction as I have suggested, increase the value set upon the
appearance of a paper in our Transactions, we might take
means to attract to ourselves varlous communications from
sources external to our Society, which at present naturally
follow the course of the stream that carries them to the
Journal.

Another source of the deficiency in question, appears to
me to lie in the desultory mode in which a large proportion
of our microscopic observers apply themselves to the use of
the instrument. When we contrast the products of British
and of German microscopy, and see how completely inverse
are the proportions between the values of the instruments em-

20 Address of the PREsIpEN’.

ployed, and of the results obtained, in the two countries
respectively, we cannot but feel some shame at the low position
we take. Now it may be said, that there are so many more in
Germany who can make microscopical observations a special
object of pursuit, devoting to it a large proportion of their
whole time, than there are in this country, that the difference
in result is not to be wondered at. But this | feel satisfied is
by no means the whole of the cause of difference ; for if those
among us who are able to give but a few hours a week to
microscopic research (which has been almost constantly my
own case), would but apply those few hours to the prosecution
of some definite department of study, they would come to
feel, 1 am confident, a far higher interest in their pursuit,
and would be in a far more favourable position to add some-
thing to the common stock of knowledge, than by expending
their time in desultory observations. And this will be espe-
cially the case, when the student, in the selection of his
department, consults his means and opportunities for investi-
gating it, as well as his tastes, so as to protect himself as
much as possible from being cramped in his inquiries by
want of the necessary material. There is always, of course,
a danger that the inexperienced inquirer will not duly inter-
pret what he sees, and that he may draw wrong deductions
where he observes aright; but this danger is greatly dimi-
nished when he confines his attention within a narrow range,
instead of trying to comprehend the whole of the “ world of
small” within his survey; since he will find it much easier to
acquire that guiding knowledge which already forms part of
the fabric ae physiological science, when the required amount
of that knowledge is limited, instead of being voluminous ;
and his éornective experience will be much more speedily
rendered precise and efficient, when it is constantly brought
to bear on the same class of facts, than when it is only occa-
sionally called into play through the too-wide range of his
observations. I should be far, oie er, from recommending
any one to limit himself entirely to a single department of
microscopic study; on the contrary, the highest education
of the eye, or rather, of the perceptive mind (for it is after all
the mind that sees, and not the eye), can only be attained by
a widely-extended course of observation, And every young
microscopist, in first training himself in the knowledge of
what to observe and how to observe, will do well to examine
objects of the most varied kinds, and to learn as much about
them as his time will permit. But it is when this preli-
minary education has been passed through, that I strongly
urge the limitation of the attention to particular departments

Address of the PResiDENnv. 21

of research, as the means by which alone, in this, as in every
other branch of scientific inquiry, can any really good results
be attained.

I hope that I shall not be supposed desirous of trumpeting
the merits of my own production, if I say that in the ‘ Manual
of the Microscope,’ which I have just brought to a conclusion,
I have especially aimed, on the one hand, to put the young
microscopist in possession of what it is most essential that he
should know at starting, on each of the most important topics
to which his attention may be directed ; and on the other, to
point out how much remains to be known, and to guide him
into the path of research which he may follow with the great-
est likelihood of beneficial results. And I cannot point toa
better example of the advantage to be derived from the steady
devotion of the attention to a definite object, than is presented
by the admirable contributions which have been made during
the last year by Mr. Wenham, to two most important depart-
ments of vegetable physiology; especially by his memoir on
Vegetable Cell Development, which appears in the last part
of our Transactions (Jan. 1856). To this I shall presently have
occasion to make particular reference; and I shall now only
remark, that I look upon it as one of the most important
rectifications which the current doctrines of this science have
ever received ; and that, although the product of one who
must be considered an amateur rather than a professor of
science, it would, in my opinion, do credit to the most accom-
plished physiologist. 1 should have hesitated, perhaps, at
pinning my faith upon Mr. Wenham’s statements, had it not
been for two circumstances which have had a powerful influ-
ence with me: in the first place, the care in observing, and
accuracy in recording, of which Mr. Wenham’s previous
paper on the ‘ Rotation of Sap in Vegetable-cells’ gave satis-
factory evidence ; and secondly, the coincidence of the results
of Mr. Wenham’s researches and conclusions, with those
towards which many recent inquiries on the history of cell-
development seem to me to converge.

It-is of great importance to the progress of any department
of Science, that we should from time to time review the
state of our knowledge on those fundamental questions which
affect its condition and aspect; and it appears to me that the
time is now come, when we must take such a review of the
Cell-theory of Schleiden and Schwann, in its relation to
Vegetable and Animal Physiology. ‘To such a review I pro-
pose now to lead you: it must necessarily, from the briefness
of the space at our command, be a very cursory one ; but I
venture to hope that I may succeed i in so placing before you

22 Address of the PresipENtT.

the aspect under which the questions at issue present them-
selves to my own mind, as to lead you to a conception of
the mode in which (as it appears to me) their solution is to
be sought for. That I have myself fully attained that solution
I dare not affirm. That the principle I offer to you, however,
is more consistent with known facts, than are the doctrines
commonly entertained, I feel a very strong conviction,

Although the general organization of Plants was so far
understood at the time when Schleiden first came before the
public, that every vegetable tissue was recognised as essen-
tially cellular in its nature, yet I consider it to have been by
him that the fundamental truth was first broadly enunciated,
in 1837, that, as there are many among the lowest orders of
plants in which a single cell constitutes the entire individual,
each living for and by itself alone, so each of the cells, by the
aggregation of which any individual among the higher plants
is formed, has an independent life of its own, besides the
‘incidental’ life which it possesses as a part of the organism
at large; and that the doctrine was first proclaimed, that the
life-history of the individual cell is, therefore, the very first
and absolutely-indispensable basis, not only for Vegetable
Physiology, but (as was even then foreseen by his- far reach-
ing. mental vision) for the science of life in general, The
first problem which he set himself to investigate, therefore,
was, how does the cell itself originate? It is unfortunate that
he should have had recourse for its solution to some of those
cases in which the investigation is attended with peculiar
difficulty ; and it is, doubtless, in great part to this cause, that
we are to attribute certain fallacies in his results, of which
subsequent researches have furnished the correction.

The publication of the ‘ Microscopical Researches’ of
Schwann, in 1839, marks a like era in Animal Physiology.
For although the doctrine could not be said to be a new one,
that each integral part of the animal body possesses an inde-
pendent life of its own, in virtue of which it performs a
series of actions peculiar to itself, provided that the condi-
tions of these actions be supplied, yet it derived a new
significance from the idea with which he connected it, that
the integral parts are either cells or derivatives from cells, and
that their independent life is, therefore, cell-life. This idea,
avowedly suggested by that of Schleiden, was based by
Schwann on the apparently-satisfactory results of his micro-
scopic observations on the development of the animal tissues.
For he found, that however diverse may be the structure and
actions of the component parts of the animal organism in
their fully-developed condition, there is a period in its

Address of the PRresiDENT. 23

history when it is nothing else than an aggregation of cells,
all apparently similar to each other; and as in some of the
tissues—for example, in the blood-corpuscles, fat, cartilage,
epidermis, epithelium, and the grey matter of the nervous
centres—the cellular character is preserved throughout life,
so might it be reasonably inferred that the rest are derived
from cells, by a metamorphic process whose consecutive
stages might be traced by microscopic observation. This
was the problem which Schwann set himself to elucidate, and
which he has been generally considered to have gone far to
solve. For although an exception was early taken by
various observers both on the continent and in this country,
in regard to that simple fibrous tissue which is formed by the
fibrillation of the effused blastema or organizable plasma of
the blood, almost every microscopic observer, down to a very
recent period, who has devoted himself to this department of
inquiry, has taken Schwann’s idea as his guide, and has con-
sidered it to be his main object to extend and complete it,
by more fully elucidating the series of steps by which bone,
tooth, shell, muscle, nerve, &c., are evolved from the cells in
which they have have been almost unquestioningly believed
to originate.

The doctrine of Schwann and his followers, however, has
lately been the subject of very acute criticism on the part of
Mr. Huxley; who has urged many arguments for the conclu-
sion, that the cell is not the essential integer of the living
organism which it has been, and still is, held to be by most
physiologists ; that it is only one out of many forms of organic
structure, into which the organizable blastema may evolve
itself; and that many animal tissues may form themselves
directly out of this blastema, without undergoing the inter-
mediate condition of cells.*

Although I am not by any means disposed to go as far as
Mr. Huxley in abandoning the cell-doctrine of Schwann and
his followers, yet I cannot but admit the correctness of much
that he has urged. ‘The essential truth, however, seems to
me to lie between the two extremes; in other words, the cell-
doctrine of Schwann can only be accepted when the word
“cell” is understood in a sense much wider than that to
which he limited it; but when it has been thus modified,
there does not seem to me to be any adequate reason for
relinquishing it. Fresh light having been thrown upon the
subject by recent researches into the lowest types both of

* See his Memoir on the Cell-Doctrine, in the ‘ Brit. and For. Med.-

Chir. Rev.,’ vol. xii.; and his article, ‘ Tegumentary Organs,’ in the
‘ Cyclop. of Anat. and Physiol.,’ supplementary volume.

24 Address of the PRESIDENT.

vegetable and animal life, I shall first proceed to inquire how
far these researches tend to modify our idea of what consti-
tutes a cell; and shall then test these modifications by the
results of inquiries into the structure and development of
more complex organisms.

The typical vegetable cell has commonly been considered
to consist, externally, of the cellulose wall,—next to this, of
the primordial utricle,—within this, of a layer of protoplasm,
usually mingled with chlorophyll-granules,— and, finally, of
the liquid cell-contents. But we find, among the simplest
Protophytes, that all the functions of vegetative life are per-
formed by beings which do not present any such differentia-
tion of parts. Thus each individual of the Palmoglea
macrococca (Kutzing) seems to be a particle of viscid plasma
containing green granules, having neither definite limitary
membrane on its surface, nor definite cavity in its interior ;
and this is surrounded by an indefinite gelatinous envelope,
which usually coalesces with that of other similar particles,
so as to form a continuous slimy matrix. Now each of these
particles has a nucleus like that of fully-developed cells; it
increases by drawing into itself nutritive materials, which it
converts into the organic compounds it requires for its aug-
mentation; it undergoes duplicative subdivision, by which
the single particle gives origin successively to two, four, eight,
&c., after the ordinary method of multiplication of unicellular
plants; and finally it conjugates with another like itself, the
substance of the two particles being fused together in such a
manner as to demonstrate the non-intervention of any limitary
membrane, and the product being a “ spore” or rather a “ pri-
mordial cell,” which originates a new generation by the re-
newal of the process of duplicative subdivision.

Now if we compare the life-history of this Palmoglea with
that of any unicellular plant that may be familiar to us,— one
of the Desmidiacee for example,—we shall see that in all
essential particulars it is the same; and that the only differ-
ence lies in the less-developed condition of the former as com-
pared with the latter. For if its nearly homogeneous mass of
protoplasm were to take upon itself that tendency to differ-
entiation of its component parts, which operates in the pro-
duction of the perfectly-developed vegetable cell, a very easy
transition would speedily manifest itself from one condition
to the other. For the surface of the protoplasm would gradu-
ally undergo condensation, so as at last to be converted into a
more or less definite membrane, the “ primordial utricle ;” *

* It is maintained by some recent observers, that the ‘“ primordial
utricle” of Mohl is not to be regarded as a proper membrane, because it is

ee

Address of the Presipent. 25

at the same time, ‘‘ vacuoles” filled with a more liquid mate-
rial would appear in the substance of the protoplasm, and
these would increase and coalesce, until at last the principal
part of the interior would be occupied by the watery fluid,
the viscid protoplasm being confined to the layer immediately
lining the primordial utricle. Further, the secretion from
the surface, instead of being a soft gelatinous slime, would
constitute a firm protective envelope,—the cellulose wall.
Now this is what may be actually seen, in following the evo-
lution of the “ zoospores” of Confervee, &c., into perfect cells ;
for these zoospores are nothing else than protoplasmic parti-
cles, formed by the subdivision of the contents of the cell
from which they are set free, having one or more filamentary
prolongations, by the vibration of which they are propelled
through the water; and it is not until they have fixed them-
selves, and have begun to grow, that they present any indica-
tion of that distinction of parts, which I have spoken of as
characterizing the typical cell.

There is another phase in the lives, not only of Protophytes,
but of more highly-organized plants, in which, according to
recent observations, a most important functional act is per-
formed by particles of protoplasm not yet furnished with a
cell-wall. Thus in Vaucheria, in which the existence of dis-
tinct sexes, and the performance of a true generative act has
been substantiated by the admirable observations of Prings-
heim, it seems very clear that while the contents of the sperm-
cell are metamorphosed into self-moving antlerozoids which
make their escape from it, those of the germ-cell simply form
an aggregate spherical mass in its interior, which, at the time
of the entrance of the antherozoids, has no limitary membrane.
The antherozoids, coming into contact with its surface, swarm
over it, and seem to undergo dissolution upon it ; and it is not
until a fusion has thus been accomplished between the con-
tents of the sperm-cell and those of the germ-cell, that the
product of this fusion becomes invested with a definite mem-
brane, and is thus developed into acell. The observations of
Dr. F. Cohn upon the generation of Spheroplea annulina are
to precisely the same effect; and Dr. Pringsheim, carrying out
more fully the observations of Thuret on the fertilization of

simply the superficial layer of the protoplasm more condensed than that
which it encloses. It does not appear to the Author that this constitutes
a sufficient reason for recognizing it as a definite membrane, where it has
a membranous consistence. And the controversy will be seen to be one
of words rather than of things, when the presence or the absence of this
membrane is viewed as a matter simply depending upon the degree of
differentiation which the protoplasm may have undergone.

26 Address of the Presivenv.

the Fuci, has ascertained that the same holds good in their
case,

Thus, then, we are driven either to admit that the essential
integers of the vegetable organism,—that which may not only
maintain an independent existence, but may increase and mul-
tiply both by self-division and a true generative process,—is
not (as we have hitherto supposed it to be) a cell; or we are
constrained to modify our definition of a cell, so as to make it
include bodies which do not possess the attributes that have
been hitherto involved in this designation. Whichever we do,
we should keep constantly in mind the relationship of the two
objects. For the nucleated particle of protoplasm, although
not structurally a cell, is a cell physiologically, possessing all
its most important functional endowments; and although it
may never develop itself into the type of a cell in a few of
the lowest Protophytes, which pass the whole of their lives in
this homogeneous condition, yet in by far the greater number
this simpler state is but transitory, the homogeneous particle
of protoplasm speedily differentiating itself into a true cell ;
so that although not a cell actually, it may be regarded as
a cell potentially. Instead, therefore, of characterizing the
simplest type of vegetable organisation as a cell, having a
distinct membranous envelope and liquid contents, we should
more correctly describe it as a nucleated particle of protoplasm,
that may either remain in that low grade of incipient organi-
sation of which a homogeneousness (approximating that of in-
organic bodies) is the distinctive feature, or may make that
first advance in organisation which consists in the differentiation
of its substance into the more solid envelope and the more
liquid interior, the cell-wall and the cell-contents.

Now it is in showing that a process essentially the same takes
place in the first formation of new organs in the higher plants,
that the great value and interest of Mr. Wenham’s paper con-
sist. It has usually been supposed that every leaf originates
in the duplicative subdivision of a certain cell of the axis, and
that its subsequent extension is due to the continuance of the
like process of cell-multiplication. Mr. Wenham has shown,
on the contrary, that (in certain cases, to say the least) the
leaf originates in a layer of protoplasm, which is in the first
instance homogeneous, but in which large vacuoles, disposed
with a certain degree of regularity, soon make their appear-
ance; these vacuoles become the cavities of the first cells,
whilst the plasma between them, acquiring increased consist-
ence, become the walls of these cells. Sometimes, when one
of the first-formed vacuoles is unusually large, it is divided
into two by the extension of a bridge of protoplasm across it ;

Address of the Prestvent. 27

on the other hand, if the plasmatic division between the
vacuoles should be unusually broad, a new vacuole forms in
its substance. Now this mode of cell-development I believe
to be altogether a new fact to physiologists ; and although Mr,
Wenham’s observation stands as yet unconfirmed, yet it
accords so well, on the one hand, with the facts which I have
stated with regard to the simpler Protophytes, and on the
other, with appearances which I have myself observed in
various animal structures, that I feel a strong couviction of its
essential truth.

If, now, we direct our attention to the Protozoa, or simplest
forms of animal life, with a view to inquire whether there be
among them any phenomena of a parallel kind, we are at once
struck with the strong resemblance which their condition bears
to that of the humblest Protophytes. Taking the well-known
Actinophrys sol as a typical example, we find that it consists
of a nucleated particle of “ sarcode” (the equivalent of the
vegetable “ protoplasm’), whose destitution of anything like
limitary membrane is evidenced by its extraordinary power
of extending itself into filaments, which, when they happen to
meet each other, undergo a complete coalescence. Yet this
nucleated particle behaves, in many respects, as a true cell,
It draws nutrient material into its interior, applies it to the
augmentation of its own substance, and multiplies itself by
duplicative subdivision. It has been supposed even to per-
form the generative act by conjugation with other particles
like itself; but recent observations upon Actinophrys and
allied organisms, have rendered it very doubtful whether
the fusion of two of these particles is a real conjugation;
since no special product has been observed to result from
it; and not only two, but several, individuals have been seen
thus to coalesce together, the composite mass afterwards
resolving itself again into isolated particles not apparently
differing in any respect from the originals. What is the true
meaning of this act, therefore, we are at present unable to
affirm ; but the fact, however we may interpret it, is in itself
extremely significant, as affording an additional proof of the
homogeneousness of the sarcode-body of the <Actinophrys.
I need scarcely stop to remark, that the same is true of the
animal bodies of the Foraminifera generally ; for these, in so
far as we are acquainted with them, are nothing else than
homogeneous particles of sarcode, extending themselves into
pseudopodia, whose coalescence, when they happen to encoun-
ter one another, affords ample evidence of the non-existence
of any limitary membrane. In Ameba, the distinction between
cell-wall and cell-contents begins to show itself; the super-

28 Address of the PRESIDENT.

ficial portion of the sarcode having decidedly more consistence
than the interior ; and the pseudopodia being much less freely
extended. Still, however, the consistence of this external
layer is not such as to present any obstacle to the reception
of alimentary particles into the interior of the sarcode-body
through any portion of its surface, or to interfere with the
rejection of indigestible particles,—the temporary orifice, in
either case, being at once closed by the coalescence of its
edges ; so that there is obviously no definite limitary mem-
brane, notwithstanding that the liquidity of a large part of the
interior substance allows a free movement of granular particles
in every direction, as I observed many years ago. Thus, the
Ameba seems to me to represent that condition of the vege-
table cell, in which the primordial utricle is distinguishable
as the external more condensed layer of the protoplasmic
mass, but does not possess the distinctness of a proper mem-
brane. A more advanced stage is seen in the curious Gre-
garina, which must be regarded as corresponding with the
Protozoa in the simplicity of its organization, whilst it resem-
bles the Hntozoa in the peculiarity of its habitat. For here,
the distinction between the cell-wall and the cell-contents is
decidedly marked ; the former becoming more consistent, and
the latter more liquid. The body undergoes great changes
of form, but no pseudopodial extensions are sent forth; and
the nutrient materials being imbibed in a liquid state by the
whole surface, neither are solid particles introduced by an
oral orifice extemporised in the superficial layer, nor are
rejectamenta extruded through a like extemporised anus,
Passing-on to the Jnfusoria, we find much reason to regard
these simpler forms (at any rate) in the light of cells modified
for an independent existence; and their essential difference
from Actinophrys and Amba seems to lie in this, that the
external layer of the sarcode is condensed into a more definite
limitary membrane,—a change which involves other altera-
tions. For, in the first place, the body can undergo compara-
tively little change of form ; and no pseudopodia can be sent
forth. And, secondly, as the alimentary particles can no
longer be introduced through any point of the surface, a
definite orifice is left in the membranous envelope, into
which the nutrient materials are driven by the peculiar dis-
position of the cilia; and, in many cases, a definite anal
orifice is also provided, through which indigestible matters

may be ejected.

Thus, among the Protozoa, as among the Protophyta, whilst
we trace a gr adual advance in the differentiation of the homo-
geneous particle of sarcode into the true cell, we find vast

Address of the PResiDEN’. 29

multitudes of beings passing their whole lives (so far, at least,
as we are acquainted with them) in that earlier and simpler
condition, in which no such differentiation has taken place,
and in which, therefore, the structural constitution of a cell
has not been attained,

Now before I pass on to inquire how far this condition
finds its parallel in the elementary parts of higher organisms,
[ wish to stop for a moment, to notice how strongly the
differences between the Vegetable and Animal kingdoms are
marked out, even in those lowest and simplest forms of both,
which we have been just engaged in considering. For the
Protophytes, like the most perfect Plants, draw their nutri-
ment from the inorganic compounds which are everywhere
within their reach,—water, carbonic acid, and ammonia ; by
decomposing carbonic acid, they give off oxygen; and they
form for themselves the starch and the chlorophyll, the cellu-
lose and the albumen, which they apply to the augmentation
of their own substance. On the other hand, even those hum-
blest Protozoa, the Rhizopoda, can only exist (so far as we
can see) upon organic materials previously elaborated by
other beings : these they receive “ bodily” into their interior ;
and though mouth, stomach, intestine, and anus, all have to
be extemporized every time that the animal feeds, yet the
digestion which the alimentary particles undergo in its
interior, is not less complete than that which is performed by
the most elaborate apparatus which we anywhere meet with ;
and the nutrient materials thus obtained seem to be appro-
ptiated, without any further conversion, to the augmentation
of the substance of the body. Thus, notwithstanding the
remarkable analogy which these two orders of beings exhibit,
I cannot see that any difficulty need be experienced in
separating them, when we are acquainted with their mode of
nutrition. The Gregarina constitutes no real exception; for
although it imbibes its nutriment through its entire surface,
like the Protophyte, yet that nutriment has been previously
digested and prepared for it by the animal whose body it
inhabits ; and in the absence of any oral orifice or digestive
apparatus of its own, it corresponds with a far higher group
of animals, the Cestoid Worms, which live under the same
conditions. Some recent observations, it is true, would seem
to invalidate this distinction, by showing that certain rhizopods
and infusoria have their origin in undoubted plants ; but we
must be permitted for the present to withhold our assent from
conclusions so strange, and to question whether they may not
be invalidated by some unsuspected fallacy. It has been well
remarked, however, that ‘‘ there is no limit to the possibilities

VOL. IV. . d

30 Address of the PrestDEN’T.

of Nature ;” and | should be the last to attempt to set up as
fixed laws what are merely the expressions of the present state
of our knowledge, or to wish to throw discredit on the ob-
servations of accomplished and careful microscopists, merely
because they overthrow distinctions which | had imagined to
be well founded. I would strongly recommend the observa-
tions of Professor Hartig (Quart. Journ. of Microsc. Science,
Vol. IV., p. 51) and of Mr. Carter (Ann. of Nat. Hist., Feb.,
1856) to your attentive scrutiny ; and hope that some of our
members may be able, ere long, to furnish either a confirmation
or a refutation of them.

Turning, now, to some of those parts of the fabric of higher
animals, in which a cellular organization has been described
by some observers and denied by others, I think I shall be
able to show that the discrepancy is capable of being recon-
ciled, by the application of the principle of progressive dif-
ferentiation to the mass of sarcode in which any such organ
originates. Thus having found, in various kinds of shells,
certain instances in which a very definite cellular organization
appeared to me to exist,—others in which this organization
was less definite, though still (as I thought) unmistakeably
present,—others in which it was only faintly indicated,—and
others in which I could discern no traces of it ;—and having
also met with gradations from one condition to another, even
in the very same shells ;—I thought myself justified in con-
cluding that the animal basis of the shell-substance must have
been originally cellular in every case, but that the divisions
between the cells must have been lost in some cases by a very
early coalescence. Mr. Huxley, on the other hand, has recently
expressed an opinion,* founded on an examination of my own
preparations, that the whole of my interpretation is erroneous,
and that no cellular structure can really be discerned in shell.
Now in the justice of this verdict, I cannot say that I am pre-
pared to coincide ; on the other hand, I am quite ready to
admit that my original interpretation requires modification.
Taking the general history of the first formation of a leaf from
a layer of protoplasm, as probably applicable to the formation
of a lamina of shell from a layer of sarcode, | should now
interpret the appearances which my preparations exhibit, as
follows :—In those forms of shell-substance in which I can
discern no structure whatever, and in which a continuous
membrane is left after decalcification, | should be disposed to
think that the entire layer of sarcode has undergone calcifica-
tion, before any differentiation of parts had begun to take place
in it. In those again in which (as in Mya and Thracia) a

* ¢Cyclopedia of Anat. and Physiol.,’ Supplement, p. 489.

Address of the PRresipEnv. 31

cellular arrangement is more or less obvious in the section,
but in which no distinctly-cellular residuum is left after decal-
cification, I should infer that the processes of vacuolation and
of consolidation had commenced, but bad not proceeded far,
when the calcification took place, Lastly, in those in which
(as in Pinna) a very definite residuum, apparently cellular, is
left after decalcification, the very striking resemblance which
this bears to that stage in the vacuolation and consolidation of
a layer of protoplasm about to form a leaf (as described and
figured by Mr. Wenham) which immediately precedes the
formation of distinct cells, induces me to think that such must
have been the stage in which the sarcode-layer must have
undergone calcification. Hence, whilst agreeing with Mr.
Huxley that in few (or perhaps none) of the structures which
I have described as cellular, are any complete cells ordi-
narily formed, I still believe Pata in all of them there has been
a nisus more or less operativ e, towards the development of
cells; their differences lying solely in the greater or less
degree of differentiation, tending towards the production of
perfected cells, which had manifested itself in the sarcode at
the time of its eee

I am strongly disposed to believe, that the same doctrine
will apply to many other animal structures, in which the pre-
sence of a cellular organization is affirmed by some and denied
by others. If, for example, you look at the scale of an Fel,
you observe that its otherwise homogeneous substance is marked
out by ovoidal spaces, which suggest the idea of cartilage-cells
with an intervening matrix. By Professor Williamsan, who
has carefully studied the structure of fish- scales, a layer af this
kind has been shown to be of very general occurrence ; and
he considers these ovoidal spaces to be “ botryoidal concre-
tions” of calcareous matter, having no relation whatever to
cells. And he puts the like interpretation on analogous
appearances exhibited by various egg-shells, which have been
regarded by Professor Quekett and others as indicative of a
cellular organization. Now the microscopic appearance of
the scale of the Eel so precisely resembles that of the leaf-
forming layer of protoplasm, as figured by Mr. Wenham, that
I can scarcely doubt that its ovoidal spaces are vacuoles
formed with a view (as it were) of becoming cells ; and that
the regularity of the shape and disposition of the calcareous
concretions is determined by that of the vacuolations. And
the condition of such egg-shells as exhibit an appearance of
cellular structure, so closely resembles that of many shells of
mollusks, in which there is a cellular areolation without well-

32 Address of the PresiDENT.

defined membranous partitions, that 1 can scarcely hesitate in
attributing to it a similar origin.

The general doctrine, then, which seems to me best to
express the facts I have stated, is that those essential endow-
ments which we have been accustomed to attribute only to
the typical cell, may exist in that comparatively-homogeneous
substance which is commonly termed “ protoplasm” in the
vegetable kingdom, and “ sarcode” in the animal; that iso-
lated particles of this substance may comport themselves after
the manner of true cells, although no distinction between
cell-wall and cell-contents may have made itself apparent ;
and that various organs and tissues among the higher plants
and animals have their origin in larger extensions of the same
substance, in which the process of cel/ulation may either pro-
ceed to the complete evolution of an aggregate of perfect cells,
or may be stopped at any point, so as to leave but faint traces
of the tendency in question. I have already adverted to the
belief which I have from the first entertained, that in the
animal body, the fibrillation of the blastema may take place
quite independently of cellulation; and I am much disposed
to think that the formation of other tissues may take place
by alike direct process of conversion. But I wish to take
this opportunity of protesting against the assertion, that
where no perfected cells can be demonstrated, there is not a
tendency to a cellular organization, however incomplete may
be its result. It would be just as unphilosophical, in my
opinion, to assert that the white fibrous tissue does not mani-
fest the tendency of the blastema to fibrillate, because it
seldom exhibits isolated sharply-defined fibres like those of
the yellow or elastic tissue.

Some apology might, perhaps, seem due for thus oceupy-
ing your time in an abstract physiological disquisition ; but
next to correct observation, is the right interpretation of what
we see; and, in fact, it is often extremely difficult (as is
obvious in the history of this very inquiry) to distinguish
between the impressions which the objects themselves make
upon our minds, and the ideas which we connect with those
impressions. And I am desirous that those whom I have
now the pleasure of addressing, should be put in the way of
examining for themselves into the merits (1) of the cell-
doctrine as commonly held, (2) of the opposite view put
forward by Mr. Huxley, and (3) of the intermediate doctrine
which I have this evening endeavoured to expound.

Address of the PRrestpENv. 33

It now only remains for me, in resigning the chair to my
successor, to thank you most gratefully for the kind indulg-
ence which you have so constantly extended to me; and to
express my regret that I have not been able to do more to
promote the interests of the Society, by myself furnishing
original communications to its meetings. It is known to
many of you, that the small amount of time which I can
spare for original research, has long been devoted to one
special object, the elucidation of the structure and physiology
of the Foraminifera; and the liberal assistance which has
been afforded me by the Royal Society in the prosecution of
my researches (whereby I have been enabled to procure the
unrivalled series of microscopic drawings that I have exhi-
bited from time to time at our meetings), makes me feel it
but common gratitude, to place before that Society the
systematic results of my researches. And further, the
number and variety of demands upon my time have entirely
precluded my making any such active exertions to obtain
communications from others, as may not unreasonably be ex-
pected from your President. I have the gratification of
believing that my successor may be much more able than I
have been, to contribute to your welfare in both these modes ;
and it is, therefore, with much satisfaction that I look for-
ward to being replaced by one of the oldest members of the
Society, who has given evidence of such extensive attainments
in various departments of Microscopical Science, and who
will, I feel confident, do the fullest credit to your choice. I
have only to beg you to believe, that the warmest desire to
promote the interests of the Society has never been wanting
on my part, and that nothing but the coercion of circum-
stances, which I could not control or resist, has prevented me
from more fully manifesting the sincerity of that desire in
labour for your benefit.

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Micro. Trans., Vol. IV., Pl. II.

Micro, Trans., Vol. IV., Pl. III.

Fie 4,

( 85)

On the Post-rertiary Diatomacrous Sanp of GLENsHtrRa.
Part TI: Containing an account of a number of additional
undescribed species. By W1tttaM Grecory, M. D.,F.RS.E.,
M.R.I.A., &c.; Professor of Chemistry in the Univ ersity
of Edinburgh. Illustrated by numerous figures drawn from
Nature, by R. K. Greviiyie, LL.D., F RS. E., &c., and
engraved by Turren West, Esq. (Plate )

(Read March 26, 1856.)

In the first part of this communication * I described the pecu-
liar locality in which the Glenshira Sand occurs, and pointed
out, that the remarkable mixture of marine and fresh water
forms which it contains, was a proof that, when this sand or
mud was deposited, the fresh-water lake, then filling the
upper part of the valley, and standing, of course, at a higher
level than it now does, must yet have occupied the same
relative level, compared with the sea, which it now occupies,
when it is confined to the lowest part of the valley, and being
exactly at the level of half-tide, flows into the sea at low
water; while, at high water, the sea flows into the lake. This
state of matter produces in the lake, at this moment, a mix-
ture of marine and fresh-water species, not only of diatoms,
but also of other tribes, both animal and vegetable. And as
the existence of a similar mixture in the sand now under ex-
amination, deposited at the higher level, implies that at the
period of its deposition the ieliiee lev els of the sea and of
the lake were the same as now, while we see that the lake
now stands at a lower level than formerly, we infer, that since
that period the land has risen, or the sea has fallen; a con-
clusion justified and supported by many other geological phe-
nomena in the estuary of the Clyde, with which Loch Fine,
the arm of the sea into which the Dhu Loch of Glénshira
flows, communicates.

In the same paper I gave a list of about 215 known species
of Diatoms, and nearly 20 undescribed species, which I had
found in the deposit; a number of species far exceeding that
hitherto found in any other similar deposit, so far as is known
to me. This, I conceive, indicates that the circwmstances
which favoured the mixture and accumulation of a must
have been of very prolonged duration.

At the same time I stated that there Setanta about as
many more undescribed forms as those I had been able at that
time to figure, and that these should be figured and described
on some later occasion. I now proceed to fulfil that promise.
I must explain, however, that it is impossible for me to com-

* © Quarterly Journal of Microscopical Science,” vol. iii., p. 30.
VOL. IV. eC

36 Dr. Grecory, on the Post-tertiary

plete the investigation in the present paper. In the first
place, the sand is not yet exhausted ; for although I have ex-
plored about 600 slides of it, new forms are still from time to
time occurring. Secondly, it has been found impossible to
finish the study even of the whole of those which I had ob-
served in it in 1854, and to prepare figures of them. I pro-
pose, therefore, only to describe and figure, at this time, such
of the new forms as have been duly studied. This is, no
doubt, the majority of them ; but it will require a third paper
to complete the examination, more especially of the smaller
forms, among which, as well as among those of the larger
which have not yet occurred entire, much remains to be done,

Before describing the new forms, | must add to the list of
known species formerly given the following, many of which
were accidentally omitted. Others have since occurred to me,
and ‘a few have been pointed out to me by Mr. Okeden, well
known as a zealous observer. These I have also myself seen.

Additional List of known Species.

235.* Cymbella sinuata, W. G, 250. Navicula Pandura, Bréb. (?)
236. Amphora membranacea. 251. Pinnularia megaloptera, Ehr.
237. i salina. 252. 3 biceps, W. G.

238. rs hyalina. 253. a linearis, W. G.
239. Amphiprora paludosa. 254. 8 subcapitata, W. G.
240. Campylodiscus Ralfsii. 255. ‘a gracillima, W. G.
241. Actinocyclus undulatus. 256. Pleurosigma distortum.

242. Actinocyclus ? 257. re intermedium.
243. Actinocyclus duodenarius, Sm. | 258. Gomphonema subtile, Ebr.
244. Nitzschia bilobata. 259. Orthosira spinosa.

245. Navicula Westii. 260. os mirabilis.

246. te obtusa. 261, Grammatophora Balfouriana.t
247. 5 Hennedii. (See Synopsis, Vol. II. Pl. LXI.
248. 3 rostrata, fig. 383.)

249, Navicula varians, W. G. (in

all its forms).

On this list I would only remark, that the species marked
W. G. have been lately described by me, as well as Nos.
248, 251, and 258, the two last as new to Britain;{ that No.
249, Navicula varians, has been also fully described by me
elsewhere :§ that No. 2438, <Actinocyclus duodenarius, appears

* These numbers are continued from Part I., in which JI gave a list of
234 species.

+ Ihave given a figure of this form, as being little known as yet. At
first it seemed to differ from the form figured by Dr. Greville, the inter-
rupted vittee being less conspicuous, the striae more so; but Iam now
satisfied that it is essentially the same form, which varies, however, more
than was at first supposed. The figure is not numbered, as it is not
intended for engraving.

t ‘ Quarterly Journal of Microscopical Science,’ vol. iv., p, 1.

§ ‘Trans. Micr. Soc., Quart. Journ. of Micr. Science,’ No. X., p. 10,
Jan. 1855.

ae

Diatomaceous Sand of Glenshira. 37

as a British form in Vol. If. of Smith’s Synopsis. I have
found in Glenshira several forms of this kind, differing only
in the number of septa, which varies from 7 or 8 to 14 or
16. I observe in Pritchard’s Animalcules, that Ehrenberg
makes a species of each number of septa ; but to judge by the
aspect of these forms in Glenshira, they are all of one species,
which I have named duodenarius, because 12 is about the
average of the septa in those I have seen there. No. 250,
Navicula Pandura, was \ast year figured by De Brébisson as
occurring at Cherbourg. I mark it with a query, because it is
doubtful whether it may not be the same species as JV. nitida,
Sm., (named in my former list,) and also because I have
great doubts as to either of these forms being correctly named.
They belong to a very striking group, in which the Glenshira
sand is somewhat rich, and which I shall have presently to
consider more fully.

Of No. 247, Navicula Hennedii, I give a figure, because very
fine specimens occur in this deposit, and the form has not yet
been figured, though it will be described in Vol. II. of Pro-
fessor Smith’s Synopsis. The two Orthosire are also new
forms; O. spinosa having been found in Braemar by Drs.
Greville and Balfour, and in Auvergne by Professor Smith,
and figured both by Dr. Greville and Professor Smith ; and
O. mirabilis having been found last summer in Wales by Mr.
Okeden, but not yet figured. I may here mention, that I had
observed and sketched both, in my earliest explorations of the
Glenshira sand, fully three years ago; but from the number
of new forms, I was compelled to postpone the study of them,
and had not been able to resume it when the naturalists above
named discovered them. But before the account of O. spinosa
had appeared, I had again found both forms in three or four
South American soils. I mention this here, because my ob-
servations on these soils have led me to doubt whether O.
mirabilis be not an abnormal state of O. spinosa.

My reasons for thinking so are: 1. That inal] the localities
in which O. mirabilis occurs, it is accompanied by O. spinosa.
2. In the Glenshira sand and in the American soils, I was un-
able to find any discoid or end view, or diaphragm, which I
could suppose to be that of O. mirabilis, except that of O-
spinosa; and I believe that Mr, Okeden has been equally
unsuccessful. 3. I found one cylinder, one-half of which had
the peculiar markings of O. mirabilis, narnely, two series of
curved or sigmoid lines, decussating and crossing the cylinder
transversely ; while the other half had all the characters of
O. spinosa. 4. In no specimen of O. mirabilis have I seen
any appearance of the usual septa, so strongly mana in

e2

38 Dr. Greeory, on the Post-tertiary

O. spinosa, which leads me to suppose that the markings are”

due to the septa having been removed and replaced by some
new internal arrangement. 5. In both forms, the ends of the
cylinders exhibit the spines, or appearance of spines, from
which OQ. spinosa is named. It was for these reasons that I
did not earlier mention QO. mirabilis as a species; and as for
O. spinosa, I had postponed it with other forms, otherwise
both might long ago have been known.

Let us now turn to the new forms. Here I must premise
that a few of those new figures were described and figured in
my former paper. I have figured these again, in some cases, be-
cause the former figures were accidentally erroneous; or in
others, on account of additional peculiarities, or because I
now understand the forms better than I was at that time able
to do. By far the greater part of the forms now given are
figured for the first time.

1. Navicula rhombica, n. sp. In my former paper are
two figures of this species, which is very frequent in the
sand. I now give two more figures, to complete the history
of it.

Length from 0:001” to 0:0025”. Form rhombic, with
somewhat acute apices as in the former figures, or elliptic
lanceolate, with obtuse extremities, as in fig. 1. Stria fine,
but easily seen with a good 1-4 or 1-5, about 45 in -O0L", but
those near the middle of the valve much more distant, so as
to be almost conspicuous ; the striz slightly inclined. Median
line strong ; nodule large and well marked. Valve colourless,
or pale yellow.

The above characters sufficiently distinguish this species
from N. rhomboides, which, in the typical form, is always
acutely rhombic, of a much darker colour, and has no definite
central nodule, the two halves of the median line ending in
sharp triangular points. The striae in JV. rhomboides are so
fine, that I have never yet been able to see them with a 1-5
of extraordinary goodness, and they are indeed hardly to be
resolved by the 1-8; they are also parallel. All these things
unite to give to WV. rhombica an aspect so entirely different
from that of WV. rhomboides, that it is impossible to confound
the two forms, where, as in the present deposit, they occur
together. I may add that the variations of NW. rhomboides,
viz., LV. crassinervia and N. interrupta, W. G., are quite distinct
from those of NV. rhombica. 1 state this, because some who
have only seen the figures of VV. rhombica in my former paper,
have supposed that it is only NV. rhomboides. Those who have
seen the forms will admit that it is not possible for two species
of the same genus to differ more thoroughly; but it is im-

me Pt

Diatomaceous Sand of Glenshira. 39

possible, in all cases, to represent in drawing, characters
which, in the forms, are perfectly satisfactory.

Since writing the former paper, bowever, I haye observed
an additional mark of distinction, which has even led me to
doubt whether the form under consideration be a Navicula at
all; for it frequently occurs in what I may eall packs, like
packs of cards, in which six, eight, or more are laid flat and
close on each other. I have represented one of these in fot i:
This is a character which | have not observed in any Navicula,
although it is easy to imagine that some species of the genus
may occur in such groups. From the fact of these packs
being so frequent in a deposit like this, so long water-tossed,
it may be inferred, that the forms composing them are very
firmly attached together in the living state. I must leave to
better authorities to decide whether this be a Navicula or not,
merely observing that it is a well-marked and beautiful species.

I believe N. rhombica to be a marine form, having seen it,
with other marine species, in a recent gathering from the
coast near Tantallan, Haddingtonshire. There were also
some fresh-water, or rather brackish-water forms, derived
from the mouth of a small brook near the spot. If it be
marine, this will be another point of distinction between it
and N. rhomboides. 1 have seen no trace of it in all the very
numerous fresh-water gatherings I have studied, though
N. rhomboides is one of the commonest forms (222.)f

2. Navicula maxima, n. sp. This was also figured in my
former paper, but I now give some additional figures of it,
both because I have since found much finer specimens, and
in order to show its usual varieties.

Form linear, broad, usually a little incurved at the middle,
with broadly acuminate apices, as in fig. 2. Also linear,
narrow and long, without constriction, as in fig. 2*. Some of
this variety are very long and narrow; and there are also
forms intermediate between 2 and 2*, as in fig. 2**. Length
from 00035” to 0:0065”, Median line strong, usually some-
what bent towards the central nodule, at least in the broader
variety. Stria transverse, parallel, reaching the median line ;
fine and close, about 50 in 0-001” in the broader, consider-
ably finer in the narrower variety. Colour of the valve in
balsam, clear straw yellow. The valve is thick and convex,
so that, when not lying quite flat, the edges become black.
It is a very striking form, and frequent in the coarser densities
of the prepared sand.

From the figure formerly given, some have supposed it to
be identical with MN. firma 6, Sm. As that form was not

+ This is the number attached tou the species in the list given in Part I.

40 Dr. Greeory, on the Post-tertiary

figured in the Synopsis, Vol. I., and I was at the time little
acquainted with it, | was at first inclined to adopt this view.
But a further examination of both forms has satisfied me
that they are distinct. NV. firma & has, even in balsam, a
strong brown colour; its striation is coarser, and far more
conspicuous, and is also slightly inclined; and it forms
several well-marked varieties, which have been described and
figured by Ehrenberg as distinct species, such as WV. dilatata,
NN. amphigomphus, and others. Now, so far as I can see,
N. maxima exhibits no other varieties than those here figured,
which I give for the purpose of comparison. Moreover, while in
N. firma, in all its forms, we have a side line on each side of
the median line, NM. mazima has usually two such lines on
each side. Lastly, both forms occur in this deposit, and are
easily distinguished by their general aspect, even under a low
power. (225.)*

3. Navicula Hennedii, Sm. I give a figure of this beautiful
species, because no figure of it has yet been published, and
because the finest specimens I have seen occur in the Glen-
shira sand. As it will be fully described in the Synopsis,
Vol. IL., I need only say here, that fig. 3 represents a very fine
one, although I have a specimen one-half larger even than
this. (247.)f

4, Navicula latissima, n. sp. This is another yery fine
species, which occurs very well developed in our deposit.

Form very broadly elliptical, with very obtusely acuminate
apices, having usually a very slight constriction before the
extremities. The sides are occasionally parallel in the middle.
Length from 0:002” to 0-005”, or even 0:006”. Some of the
shorter individuals, from the great breadth, are nearly or-
bicular. Nodule very large, median line doubly conical, the
bases of the cones meeting at the nodule. This appearance is
due to the striation, which does not reach the middle, and re-
cedes farthest from it near the central nodule. Striz rather
coarse, finely moniliform, highly radiate, and not reaching the
true inner median line. Colour of the valve, in balsam, a
strong straw yellow, occasionally light brown.

I understand that some are disposed to refer this form to
N. granulata, Bréb., which, as I stated in my former paper,
also occurs here. But I cannot do this; for in NV. granulata,
not only are the stria much less numerous, even though it is a
considerably smaller form, but they are composed of large
granules, so distant as to give a special character, from which
the name is taken. In W. Jatissima, the stria are indeed

* So numbered in Part I.
+ So numbered in the list of known forms, given at page 34.

Diatomaceous Sand of Glenshira. 41

moniliform, as in many other navicula, but this character is
far from being conspicuous. Moreover, the invariable and
decided colour of the valve distinguishes it from WV. granulata,
which is colourless. Neither have I ever seen in JW. latissima
the produced or apiculate apices of WV. granulata. I consider
N. latissima to have very well marked characters, and the
aspect of the larger individuals to be entirely peculiar.

Fig. 4 represents one of the shorter, and fig. 4* one of the
longer forms of this fine species. -(262.)

5. Navicula quadrata, n. sp. (= N. humerosa, Bréb.) This
form is allied to the preceding, and is equally frequent in the
deposit.

Form rectangular or nearly square, the ends suddenly con-
tracted to short produced apices. Length from 0:0015” to
0-005” or even more, the breadth not increasing with the length
in the longer individuals. The usual length is about 0:0025”
or 0-003”. Striz radiate, much finer than in JW. latissima,
minutely moniliform, coming nearer to the median line. Fig. 5
represents an example rather below the average size.

When I first observed this form, and sent it to de Brébisson,
he told me that he had then just found it at Falaise, and had
named it WV. humerosa; but he preferred my name as haying
been the earlier, and as more characteristic. Subsequently,
Professor Smith referred it to V. granulata, Bréb., with which
it agrees in form, while it differs from it remarkably in
striation and aspect. De Brébisson, having found it quite un-
mixed with WV. granulata, still, | believe, regards it as a dis-
tinct species,* For this reason, I give it here as such, adding,
however, that I think it probable that it may prove to bea
variety, not indeed of NV. granulala, but of JN. latissima, from
which it differs, indeed, both insform and in number of striaz,
but which it resembles considerably in general aspect. In my
paper on Navicula varians,; 1 have shown that neither outline
nor number of striz are to be relied on, in certain cases, as
specific characters, and [ shall take an early opportunity of
directing attention to other facts of the same kind which I
have since observed. I may add that in this deposit there
occur forms which, both as regards outline and striation, are
intermediate between this one and the preceding, J. latissima.
Even as a variety, however, it requires to be noticed and
figured, in order to give a correct idea of the species as we find
it. (263.)

I may here state that all the three torms, NV. Jatissima,

* It appears as such, I find, in Vol. II. of the Synopsis, p. 93, as N.
humerosa. Of course I shall withdraw my name, and adopt that of de
Brébisson, to avoid confusion.

+ ‘Quart. Journ. of Mier. Science, No. X., p. 10, Jan. 1855.

42 Dr. Gregory, on the Post-tertiary

NN. quadrata, and N. granulata, are marine forms, and that
they all occur in recent gatherings on our coasts.

6. Navicula formesa, n. sp. This is a very beautiful form,
and is frequent in the coarser densities of the deposit.

Form, an elegant linear elliptic, or elliptic lanceolate, with
somewhat obtuse extremities. Nodules large and definite ;
median line like that of many Pinnularia, such as P. viridis.
Strie slightly inclined, about 35 in ‘001”, not reaching the
-median line. There is, on each side of the median line, a
side line, parallel to it. Length from 0:003” to 0°0065." At
one time I referred NV. maxima § and this form to one species,
but in NV. formosa the striae, besides being inclined, and not
reaching the median line, are much more conspicuous, giving
to the form a peculiar and well-marked aspect. I had also
some doubts, whether it should not be referred to Pinnularia,
rather than Navicula, but I have preferred the latter, because I
believe the striz to be moniliform, though very minutely so.

Fig. 6 represents a specimen, nearly of the average size; it
is, however, often considerably longer, I have not yet seen it
elsewhere. (264.)

@. Navicula pulchra,n, sp. This very pretty form is not so
frequent in the deposit as most of the preceding species,

Form, elliptic lanceolate, almost rhombic, with a slight in-
flexion towards the extremities; not very broad. Length about
0-003." Striz not very fine, very highly radiate, and very
strongly moniliform, which gives to it a very peculiar aspect.
Fig. 7 represents what appears to be the typical form, which
I have only seen in this deposit. (265.)

8. Navicula angulosa, n. sp. This very beautiful form is
frequent in the medium densities of the sand.

Form elliptic lanceolate, rather broad, with acute apices.
Length from 0:0025” to 0-0045.” Strize conspicuous, marginal,
and bounded, internally, by an angular, rhombic space. No-
dules definite, median line sharp and distinct. It is repre-
sented of the average size in fig. 8. I understand from Mr.
Bleakley, that he has found this form on our eastern coasts,

Var. 8. Rather smaller. Form linear, sides parallel, ends
acuminate, striae more distant; otherwise agreeing with a.
Represented in fig. 8*. This also seems to have occurred to
Mr. Bleakley.

Perhaps this species ought to be referred to the genus
Pinnularia, but it is not easy to define these two genera. We
shall see presently that moniliform or costate stria are not
always to be depended on, although Professor Smith distin-
guishes them by these characters. I was at one time persuaded
to refer this form to N. palpebratis, but having carefully
studied authentic specimens of that species, I am satisfied that

Diatomaceous Sand of Glenshira. 43

they are distinct. Indeed N. palpebralis is a very small form,
while LV. angulosa is generally large and conspicuous. But
the angular space in the middle in both varieties of N. angu-
losa, is a good and permanent mark of distinction. (266.)

9. Navicula Macula,n. sp. This is a very remarkable form,
which is not rare in the lighter densities of the deposit ; but I
have never seen it elsewhere as yet.

Form elliptic in the middle, short, contracted, and again
slightly expanding to very obtuse, almost truncate apices. In
shape it is not unlike the larger specimens of Cocconeis flexellu
( Thwaitesit, Sm.). Length, 0:0015” to 0-002”. Median line
straight, abruptly terminating at two points some way on each
side of the centre. There is no central nodule, but only a
large blank space, the length of which lies across the middle
of the valve, and which looks like a stain. Beyond this,
towards each end, the valve is very finely striated. Striz about
70 in 0-001", transverse and parallel.

The peculiar blank central space, which is not at all like an
expanded nodule, differs from anything I have seen in any
other form. I have examined not less than 100 specimens,
and in none of them could I see any appearance of a central
nodule, nor could I trace the median line farther than the
margin of the blank, as we can do in so many forms where the
nodule is expanded.

Fig. 9 is a very accurate representation of this form, which
is remarkably uniform in its characters. (267.)

10. Navicula solaris, n. sp. This is a very pretty and well-
marked form, frequent in the middle densities of the deposit.
It is represented in fig. 10.

Form rhombic, long and narrow, with obtuse extremities.
Length from 0:0015” to 0:0045”. The striation is fine, but
very distinct, even conspicuous, very much inclined towards
the ends, and in the centre, where there is a small circular
blank spot, so highly radiate as to present the appearance of
a sun with rays. Strie 36 in ‘OOL". The valve is usually of
a brown colour, more or less deep, even in balsam, There is
some resemblance between the shorter individuals and P. ra-
diosa; but N. solaris, besides having finer striz, and those
more inclined, is usually much longer. As both forms occur
in the deposit, they are easily seen to differ very materially in
aspect. I have not yet observed it elsewhere. (268.)

11. Navicula Pandura, Bréb.? In the course of last year
a very beautiful form was described and figured under this
name by de Brébisson as occurring in sea water at Falaise. I
have here given under this name, as a British form, that which
is represented in fig. 11, although it does not appear to be in
all points identical ‘with, that of de Brébisson. But the Glen-

44 Dr. Grecory, on the Post-tertiary

shira sand is particularly remarkable for the occurrence in it of
several different forms of the same general type, which I figure
that they may be compared with others from different localities.

That which I have named, doubtfully, W. Pandura, is in
shape panduriform, very deeply constricted in the middle,
with the extremities nearly triangular, broad, with somewhat
acute apices. Nodule square; median line strong, double,
straight, with two dark lines, parallel to it, and close to it on
each side, converging at the ends, These lines are shades,
caused by elevations in the striz#, and similar to those in
N. elliptica, Kutz (ovalis, Sm.), and in NV. didyma. Length
0:004” to 0:005”. Striz coarse, very conspicuous, costate.
Indeed, had not de Brébisson named his form Wavicula, 1
should have called it Pinnularia, as the costze resemble those
of P. alpina. It will be seen that the next form has the same
character, (269.)

12. Navicula nitida, Sm.? I have named this form, repre-
sented in fig. 12, also doubtfully, as no description of the
species has yet appeared. It is represented in fig. 12. Form
like that of the preceding, but less deeply constricted, and the
ends longer in proportion. Length 0-003” or 0:004”. Striz
not quite so coarse as in the last, costate. I have been re-
peatedly informed that this is Professor Smith’s JV. nitida, but
I cannot reconcile this with his definition of Navicula as
having moniliform, Pinnularia as having costate striae. (270.)

13. Navicula ineurvata, n.sp. This form, which belongs to
the same group, is a true Navicula, if that generic name imply
moniliform striation.

Form approaching to that of the two preceding species, but
much more gently constricted, narrower in proportion, and
with the extremities very uniformly rounded. Median line
straight, with the dark-shaded lines on each side. Stria much
finer than in the two last, about 30 in -001", and minutely
moniliform. It is perfectly uniform in its character, and a
well-marked species. Length 0-003” to 0:004". (271.)

14. Navicula splendida, n. sp. This very fine species is also
a true Navicula, but still belongs to the same group.

Form panduriform, much constricted, very broad at the
shoulders, ends triangular and obtuse. Length 0°005" to
0-006.” Median line straight, nodule square. Stria rather
fine, compared with the two first forms of the group; but dis-
tinctly moniliform ; not reaching the median line, and leaving
on each side of it a long narrow blank space, which adds to its
apparent breadth. The aspect of this form, as may be seen in
the figures, is very different from that of the other forms of the
group. It is the rarest of them in this deposit, and, as yet, has
not occurred elsewhere. (272.)

Diatomaceous Sand of Glenshira. 45

15. Navicula didyma, var. y. To the four preceding forms
I add one more, which I do not venture to erect into a new
species. It has the form and size of a very frequent form of
N. didyma, but with the entire or costate striz of Nos. 11 and
12. This character would lead us to make it a Pinnularia,
were it not that de Brébisson, and even Professor Smith him-
self, who gives it as a character of Pinnularia, have referred,
in N. pandura and N. nitida, costate forms to the genus
Navicula. At least 1 am so informed as to JW. nitida, for I
have not seen Smith’s description of it, nor an authentic speci-
men named by him, De Brebisson’s figure of NV. pandura
speaks for itself.

I have figured the costate form, which, for these reasons, |
refer for the present to WN. didyma, in fig. 15. No detailed
description of it is necessary, and I need only say here, that I
frequently meet with it in the Glenshira sand, along with the
other forms of this group, ,which I have figured, and that,
besides the two common forms of JV. didyma, well figured
by Smith, our depdsit contains one, if not two other varieties
which have moniliform striz, and which I refer also to NV. di-
dyma, a species which, like WV. elliptica, Kitz. (ovalis, Sm.)
and W. elliptica, Sm. (Smithii, Bréb.), appears to vary much
both in outline and general aspect.

16. One of these is represented in fig. 16. It is frequent
in the deposit. I call it NV. didyma, 6. .

It is evident that all these constricted forms belong to one
group, but how they are to be classified it is not easy to say.
The following questions naturally occur :—1. Do the costate
forms constitute one or more species? 2. Are the monili-
form types of this group to be referred to one or more species ?
3. Is it possible that all these forms, whether moniliform or
costate, belong to one and the same species? and if so, how
is that species to be defined ?

If we refer them all to one species, or even if the form,
fiz. 15, be referred to NV. didyma, or figs. 11 and 12 to Navi-
cula, what becomes of Professor Smith’s definition of Pinnu-
laria, and how is that genus to be distinguished from
Navicula? I do not pretend here to answer these questions ;
but I may state, that the form fig. 15 has every appearance of
being a variety of LV. didyma (agreeing precisely, as it does,
in form and size with the commonest small form of that
species, which is very abundant in the deposit); and if that
be so, then we have moniliform and costate striae in the same
species. I may add that I have made observations on
N. elliptica, Kitz. (NV. ovalis, Sm.), a common fresh-water
form, which tend to show that it passes into NV. didyma,

46 Dr. Grecory, on the Post-tertiary

equally well known as a marine form.* And I have also
observed, that MN. eldiptica, which varies remarkably in all
obvious characters, sometimes acquires a nearly, if not a per-
fectly costate striation, though usually strongly moniliform.
As I propose soon to lay these observations before the
Society, I shall not here go farther into the subject.

17. Navicula clavata,n.sp. This very fine form, represented
in fig. 17, has at first sight some resemblance to NW. Hennedit ;
but on close inspection, it presents remarkable characters.

Form elliptic, broad, with broad rounded projecting masses
at the apices, which are the extremities of the median line.
Striation marginal, as in NV. Hennedii, but the inner bounding
line of the striated band, instead of being purely elliptic, as in
that form, becomes towards the extremities, nearly straight,
so as to form a kind of angle, giving to the included blank
space between it and the median line, a very remarkable form.
Median line complex. First there is in the middle, as in
N. Hennedii, a narrow line proceeding from each end, and
terminating on each side of the centre, and at a short distance
from it, in long rounded expansions; the other extremities
are also rounded, but larger. Between the two central knobs
lies a rectangular white space, extending in its length at right
angles to the median line, and rather narrow. It reaches
beyond the general width of the middle part, that is, the
striated portion now to be mentioned, expands at the middle.
On each side of the proper median line is a transversely
striated band, which, near the ends, touches the median line,
but near the middle, recedes a little from it on both sides.
The striated band expands into large round heads, projecting
beyond the true elliptical outline of the valve, and it also ex-
pandsa little in the middle. The white blank across the centre
appears to have at each end a small striated patch placed trans-
versely to it. The large swollen ends of the complex median
line, not only project, forming short snouts, but stand out
strongly from the surface of the valve. The striz appear rather
coarser than those of NW. Hennedii, about 20 in -001", and are
very distinctly moniliform. Length of the valve, 0-0034”,

I may here mention that Dr. Greville has found in the
same Trinidad sand which | have alluded to elsewhere in this

* J observe that in Vol. Il. of the Synopsis, Professor Smith gives, as
N. elliptica, Kiitz. var. 8, the form which I found in Lochleven, and which
resembles NV. didyma. 1 admit that it seems to be a variety of N. elliptiea,
Kiitz., but I cannot find any essential difference between it and ‘certain
forms of N. dydyma. Is it possible that N. elliptica, Kiitz. may take the
form of NV. dydyma in sea water, and that some other local cause may have
produced the same modification in the fresh water of Lochleven ?

Diatomaceous Sand of Glenshira. 47

paper, and which has yielded so many fine new forms, a still
larger and finer Navicula, to which he has paid me the com-
pliment of attaching my name. In this form also, we find
the projecting, rounded, club-like snouts to the valve, standing
out from it in the same manner. It is quite distinct from the
form here figured, although, no doubt, the two forms belong
to the same group. I think I have seen, in the Glenshira
Sand, indications of a tendency in the larger forms of Navicula
Smithii, Bréb. (elliptica, Sm.), to pass into snouted varieties,
with the snout rising in relief from the surface of the valve.

I have not met with JV. clavata, except in this deposit. (273.)

18. Pinnularia longa, n. sp. This remarkable form, of
which an average example is represented in fig. 18, is not
rare in the deposit, but, on account of its slenderness, is
seldom found entire.

Form rhombic, very long and narrow, with acute termina-
tions. Coste very conspicuous, distant, inclined or radiate,
about 12 in 0-001". Length from 0-004” to 0-008”, but
usually about 0-006". ‘The only known form to which it has
any resemblance is P. directa, Sm. But in P. directa, the
form is rather lanceolate than rhombic, while the striz are
much more numerous, and are also parallel, reaching the
median line, which those of P. longa, in the middle, at “lege.
do not reach. Moreover, P. directa, so far as 1 ae seen, is
a much smaller form. P. longa has another peculiarity,
which is, that the median line, as seen in the figure, is gene-
rally twisted. |The, valve appears very thick. (274.)

19. Pinnularia fortis, n. sp. This is a very ‘pretty little
form, and frequent in the lighter densities of the deposit. It
is well represented in fig. 19.

_ Form nearly rhombic, or rhombic lanceolate, rather short,
apices somewhat obtuse. Length from 0-002" to 0:0035.
Costa conspicuous, about 16 in -001, and apparently projecting
from the surface of the valve, for on the edge view they seem
to stand out, and the valve has, in consequence, a very pe-
culiar aspect. The valve is also very convex towards the
extremities, but concave in the middle, which gives to the
F. V. a constricted form. There is a blank space at the
centre, round which the cost radiate. There is something
about the form very difficult to reproduce in a drawing.
The coste appear very distant, yet when counted, we find
them much more numerous than we expected ; and if we
give in the figure the real number, the whole character of
the form is lost. This character is well represented in the
figure, but there are fewer cost there than in the original.
It is a very well-marked form. (275.)

48 Dr. Grecory, on Post-tertiary Sand of Glenshira.

20. Pinnularia inflexa,n. sp. This is a remarkably neat
little form, well marked, and frequent in the lighter densities.

Form elliptic lanceolate, ends acute. Striation conspicuous.
Coste subdistant, highly radiate, leaving in the centre a
rather large round blank space, about 26 in 0-001". Near
each apex is a strong black cross-bar across the valve, which
I believe to be caused by a depression in the valve, and I have
named it from this character. Length 0-0014". It is very uni-
form in its characters, and is well represented in fig. 20, (276.)

21. Pinnularia acutiuscula, n. sp. This is another well-
marked species, frequent in the finer densities. Form long,
almost lanceolate, with the sides parallel in the middle, and
slowly converging to the acute apices. See fig. 21. Length
from 0-002" to 0:0026”. Striz distinct and conspicuous in
the middle part, from being more widely separated. They
are also radiate, but less strongly so than those of the two
preceding forms. They are finer than in these forms, and are
about 30 in ‘001’. The only form to which this one has any
resemblance is P. acuta, but its peculiar form and aspect are
quite sufficient to distinguish it. Both forms occur here, and
when seen together appear quite different. (277.)

22. Pinnularia Ergadensis,n. sp. I have given this name,
from Ergadia, Argyll, to the species represented in fig. 22.

Form nearly linear, or linear elliptic, ends rounded, obtuse,
almost truncate. Length from 0-002" to 0:0045", or more.
Striation finer than in P. fortis, but conspicuous ; coste about
25 in 0-001", sub-distant, not quite reaching the median line,
somewhat inclined. It is frequent in the lighter densities,
and has a perfectly distinct aspect, so that it cannot be con-
founded even with P. fortis, the form which it most resembles,
but in which the character of the striation is totally different.

As yet, I have met with none of the species of Pinnularia
here figured, except in the Glenshira sand. (278.)

23. Stauroneis amphioxys, n. sp. This curious form is not un-
frequent in the lighter densities, and is well represented in fig. 23.

Form nearly rhombic, tending to lanceolate, with acute
apices. Valve highly convex, so as very often to pre-
sent the dark appearance of an air-bubble, and, even in the
best position, showing the margin as a broad black line.
Stauras broad, reaching the margin, very transparent, so as
often to be seen with difficulty, if in the least out of focus.
At other times it is black, from the general convexity. Striz
fine, very nearly parallel, transverse, nearly 60 in 0-001", not
conspicuous, often apparently irregular, from the convexity of
the valve. (279.)

(To be continued.)

HENrREY, on some Fresh-water Alge. 49

Notes on some Fresu-waterR Conrervoip Arex, new to Bri-
tain. By Arruur Henrrey, F.RS., Professor of Botany,
King’s College, London. (Plate LV. )

(Read March 26, 1856.)

Panpvortna Morum, Ehr.

Pandorina, Ehrenberg (Char. emend). Frond a microscopic,
ellipsoidal, gelatinous mass, containing imbedded near the
periphery, sixteen or more biciliated, permanently active
gonidia, arranged in several circles perpendicular to the long
axis of the frond. The gonidia, almost globose, with a short,
beak-like process, a red spot, and a pair of cilia which pro-
ject through the substance of the frond to form locomotive
organs upon its surface. Reproduction—1l, by the conversion
of each gonidium into a new frond itis the parent mass ;
and 2, by the conversion of the gonidia into encysted resting
spores, which are set free, and (?) subsequently germinate to
produce new fronds.

P. Morum, Ebr. (P1. 1V., figs. 1-25.) Fronds hyaline; from
about 1-80” downwards. Gonidia either sixteen, and then
arranged in four circles of 4, or thirty-two, and then in five
circles, three at the poles of 4, and the intermediate three
of 8 gonidia, which in the perfect form stand near the peri-
phery and wide apart. In the forms which produce the
resting spores, the gonidia are crowded together in the centre.
The gonidia are green, but the contents of the resting spores,
after they have become encysted, are converted into oily and
granular matter of a bright-red colour.

The description of Pandorina given by Ehrenberg, is so
incorrect, that no one would be able to determine the organism
by its aid ; but the figures in the ‘ Infusionsthierchen, al-
though =n are sufficient for identification. Pandorina
Morum has been observed by Focke* and Alex. Braunft in
recent years, who pointed out the errors of Ehrenberg in
stating that the gonidia had only one cilium and no eye-spot ;
but we do not anywhere find a clear and satisfactory account
of this creature. It was with much satisfaction that we re-
ceived early in February of this year (1856), from H. Pol-
lock, Esq., a bottle containing a vast quantity of Pandorina
Morum, which he had found colouring the water in a pool at
Hatton, near Hounslow, Middlesex.

* ©Physiolog.’ Heft., ii. 1854, Pl. 1V.
t ‘ Verjungung,’ Ray Society’s Vol. for 1853, pp. 169, 209.

50 Henrfrey, on some Fresh-water

The forms presented by this organism are exceedingly varied,
and nothing can be more beautiful than a number ‘of them
revolving slowly on their long axes in a drop of water, as
seen under a power of about 100 diameters.* In the first
place, the perfect form exhibits two patterns shown in figs. 1
and 3, and there are minute counterparts to these, remain-
ing in that state, as in figs. 7 and 9; while in the water
where the species is actively multiplying, all sizes between
figs. 13 and 14, just emerged from the parent frond, and the
full grown from figs. 1 and 3, &c., occur. The form with
32 gonidia results from the cell-division going on one stage
further than in the form with 16; but this difference is fixed
during the earliest stages of development, as the form with 16
(fig. 1) never changes into that with 32 (fig. 3), after it
has become free from the parent. In the perfect forms the
gonidia are arranged near the periphery of the frond in circles,
like the equator and parallels of latitude on a globe, so that
Pandorina resembles Cohn’s Stephanospherat more closely
than any of the other Volvocinee, that having a single equa-
torial ring of gonidia in its globular frond. Among the
forms with the isolated gonidia occur others almost equally
numerous with the gonidia collected together into berry-like
heaps (figs. 15-20); these are smaller than the others, but
equally varied in dimensions ; their gonidia resemble those of
the other form; they appear destined to form the resting spores.

The gonidia are almost globular; they have no proper
membrane, but consist of a gelatinous, granular substance
which contains a thinner fluid in the centre, as it contracts
strongly by exosmosis when strong saline solutions are ap-
plied. There is a large, nucleus-like hody (the chlorophyll-
vesicle of A. Braun) at the posterior end of the gonidium
(fig. 5), and at the opposite side is a short beak-like process,
"with a colourless space behind it; the pair of cilia arise here,
and a little to one side and below these is the reddish-brown
granule called the ‘ eye-spot.’ We have never been able to
observe a pulsating vacuole, as described by Busk and Cohn
in Volvox and Gonium.

The gelatinous frond appears to be perfectly homogenous,
without any boundary membrane. Iodine and sulphuric acid
do not colour it blue. It is tolerably resistent, and appears
solid, as it does not give way or become indented by exter-
nal pressure, as is the case with the hollow frond of Volvoz.

The fronds are multiplied by the conversion of the gonidia

* A, Braun says they revolve constantly to the right ; but they change

the direction constantly.
t ‘ Annals Nat. Hist.’ 2nd Ser., x., p. 321, &e.

Confervoid Alga. 51

into new families. If they are viewed at night, many of the
fronds may be found at rest at the bottom of the vessel (in the
daytime they assemble at the side next the light), motionless,
and with the gonidia rounded and deprived of their nucleus.
By covering up the bottle from the light, the development of
the new fronds, which naturally takes place very early in the
morning, may be retarded so as to be followed during the
morning until noon. Some of the fronds may be found with
the gonidia converted into berry-like heaps (fig. 10), others
with the gonidia already distinct (fig. 11), while many parent
fronds present the young fronds more or less regularly arranged
in the softened and expanded parent mass (fig. 12), which ulti-
mately dissolves and sets them free (fig. 13,14). They then
increase in size in proportion to the favourable conditions in
which they are placed. I have never seen anything like what
are described by Cohn in Stephanosphera as ‘ microgonidia.’*

When kept for some weeks, an increasing quantity of fronds
became accumulated at the bottom of the water, and these
chiefly of the character shown in fig. 17, but devoid of cilia;
and while many of them decayed, in others the gonidia be-
came encysted so as to form globular cellules. Left for a
fortnight, the water was found without a trace of green colour,
with merely a brownish sediment at the bottom, upon ex-
amining which, it was found to contain a large number of
berry-like forms (fig. 17), with the gonidia not only encysted,
but with their contents converted into a red, oily, granular
substance (figs. 21-25), as in the resting-spores of many Con-
fervoids. The gelatinous frond was here almost dissolved
away, and a slight pressure was sufficient to detach and
separate the cellules, which are doubtless resting-spores, and
destined to become subsequently developed into new fronds,
This remains to be decided.

The organism thus described is a well-marked and distinct
species, very different from Volvoa and Gonium, but approach-
ing near to Stephanosphera. The form which produces the
resting-spores, after losing its cilia, is Kutzing’s Botryocystis
Morum, I have met with a form like this not unfrequently,
but never before with the perfect Pandorina. Mr. Pollock tells
me that he has collected from the same pond for some years
past, but never found Pandorina before, and yet it colours
the water green this season. Volvox seems, in like manner, to
come and go at intervals of years, its revivification from the
resting-spores depending much on external conditions.

* ¢Ann. Nat. Hist.,’ 1.c. In a letter received from Professor A.

Braun since the above was written, he speaks of the forms with small
gonidia (figs. 7—9) as the ‘ microgonidial’ form. A. H., June, 1856,

VOL, IV. St

52 HEnrFrREY, on some Fresh-water

Apiocystis Brauntana, Nageli.

Apiocystis, Nigeli. Frond a microscopic, hyaline, gela-
tinous, sac-like body, attached by an attenuated base; contain-
ing numerous green globular gonidia, multiplying, during the
growth of the frond, by quaternate division, and finally breaking
out by a lateral orifice as active, two-ciliated zoospores, each
of which becomes encysted and grows up into a new frond.

A. Brauniana, Nig. (PI). 1V., figs. 26 and 27.) Frond
pyriform, 1-600” to 1-25” high, the cavity filled up by gela-
tinous matter, in which are embedded the gonidia, at first few,
increasing in number with age as far as 1600, each about
1-2000" in diameter. Niigeli, ‘ Einz. Algen,’ p. 67, Pl. ii A;
Kiitzing, ‘Spec. Alg.,’ p. 208. Fresh-water ditches, &c.

few young specimens of this little plant were observed in
January of this year (1856) in a jar of water containing
aquatic plants, brought from Wimbledon Common six months
previously. The whole collection was destroyed by frost soon
after, so that the development was not followed. Néageli (U. ¢.)
gives the following account of it:—

“The young ‘ swarm-cells’ (zoospores) attach themselves by their
ciliated point (especially to Cladophora fracta), and become invested with
a club-shaped enveloping membrane. The first division of the green
body then takes place in the direction of the axis of the vesicular envelope,
aud is repeated, in A. Brawniana, alternately in each direction of space.
During this the vesicle in which the cells (gonidia) lie, continually
expands, and generally becomes very evidently pedunculated. Young
vesicles contain a regular number of cells, namely, 2, 4, 8, 16, 32, &c. ;
but the number afterwards becomes indefinite ; in largish vesicles, 1-50”
long and 1-120” in diameter, I have counted about 800; in the largest,
about 1-25" long and 1-50" thick, some 1600 cells.

‘“‘ The cells (gonidia) are at first uniformly distributed over the whole
cavity of the vesicle. Subsequently they generally become collected on
the internal surface of the wall of the vesicle, where they lie in one or
more strata. But the cell-division always takes place in all directions
of space, the cells situated internally advancing outwards towards the
periphery. In old vesicles the cells are sometimes arranged in rings of 8
upon the wall. .

‘“* When the family of cells is mature for ‘ swarming,’ which may occur
at very different sizes and with very different numbers of gonidia, the
cells begin to move at first slowly from their places, and then gradually
to circulate more rapidly in and out about each other. The vesicle bursts
and the gonidia emerge by the orifice which is formed. Sometimes the
swarming is preceded by the state in which the cells are arranged in
parietal rings.

“The cells secrete an abundant gelatinous coating, which becomes
softened within the vesicle, and confluent into a structureless jelly. The
vesicle sometimes appears merely as the boundary line of the jelly; in
general, however, it may be distinguished as a distinct wall composed of
denser gelatinous substance (Pl. IV., fig. 25), the internal outline of which
is always distinct and sharp, while the outer is frequently indistinct and
partly dissolved.”

Confervoid Alge. 53

The vesicle sometimes presents delicate ciliary processes on
the outside. The aoneyaree have two cilia, according to

Al. Braun.* They have no ‘ eye-spot.’

CLATHROCYSTIS AERUGINOSA.

Clathrocystis, Nov. Gen. Frond a microscopic gelatinous
body, at first solid, then saccate, ultimately clathrate, (frag-
ments of the broken fronds occurring in irregularly-lobed
forms,) composed of a colourless matrix, in which are im-
bedded innumerable minute gonidia, which multiply by divi-
sion within the frond as it increases in size. (No zoospores or
resting-spores observed.)

C. eruginosa. (PI. IV., figs. 23—36.) Fronds floating in
vast strata upon fresh-water pools, forming a bright green
scum, presenting to the naked eye a finely granular appear-
ance ; when dried appearing like a crust of verdigris. Gonidia
or green cells, with a distinct membrane, about 1-8000"’ in
diameter, leaving a hyaline border at the surface of the fronds ;
full-grown fronds, 1-50” to 15” in diameter. Microhaloa eru-
ginosa, Kiitzing. (‘ Linnea,’ viii, p. 371, Pl. 8, fig. 23.)
Microcystis icthyoblabe, Kiitz., ‘ Phyc. Gen.’ ex parte. Mene-
ghini, ‘Monogr. Nostoch,’ p. 104. Microcystis eruginosa,
‘Tab. Phyc.’ i, Tab. 8. Polycystis e@ruginosa, Kiitz., ‘Sp.
Alg.,’ p. 210. ‘‘ Flos Aque,” ‘ Treviranus,’ Linnza, xvii.,
p- 51, Pl. 3. On fresh-water lakes.

This remarkable form does not appear to have been ob-
served hitherto in Britain. We found it in the autumn of
1855, forming a scum extending over a large portion of the
surface of the lake in the Royal Botanic Gardens at Kew.
A portion of it, brought home and preserved in a room ina
bottle of water, continued to grow healthily until the middle
of winter.

It is very well described in the paper of Treviranus above
referred to; but none of Kiitzing’s descriptions mention its
remarkable mode of growth or its peculiar form when perfect.
Apparently that author has only seen it in a dry state ; it
does not agree with the definitions of the genera Microcystis
or Microhaloa ; and as the name Polycystis has been occupied
in the Fungi, we have ventured to add to the already confusing
synonymy, by giving it a distinctive and characteristic name.

The smallest fronds met with are usually roundish or ellip-
soidal, of the character shown in PI. IV., figs. 28 and 34.
When quite young they appear to be solid, but as they grow
by the multiplication of the internal gonidia, and the secretion
of gelatinous matter, the expansion takes place chiefly near the

* © Verjungung,’ &c., Ray Soc. Vol. 18538, p. 209.

54 HernFrREY, on some Fresh-water Confervoid Alge.

periphery, so that the frond becomes a hollow body (just as
the stems of Grasses or Umbellifere become fistular). The
walls of the sac then give way, (figs. 29 and 30,) and as the
expansion proceeds, orifices are formed in different parts, until
the whole becomes a coarsely-latticed sac or clumsy net, of
irregularly-lobed form (fig. 31). Then this becomes broken
up into irregular fragments (figs. 832—34) of all shapes and
sizes, (giving the stratum a granular appearance to the naked
eye,) each of which recommences the expanding growth, and
becomes a latticed frond. The internal cells are very minute,
but have a distinct margin with internal granules (figs. 85 and
36). They multiply by dividing into two or four. The gela-
tinous frond always presents a transparent border or peripheral
stratum, destitute of green cells; but no boundary membrane.
exists, the surface exhibiting a softened or half-dissolved
aspect. On the approach of winter the fronds ceased to in-
crease, and by degrees most of the gelatinous masses faded to
a light brownish tint, swelled up and settled to the bottom
of the water in light flocculent clouds. They appear to
become half dissolved, and to allow the green cells to become
free, as many of the latter were found free, adhering to the
sides of the vessel; perhaps these reproduce the fronds in the
next season. No zoospores were ever detected.

The verdigris-like appearance of this Alga when dead is
most remarkable and characteristic. While growing, in its
wet state, it is rather of a yellowish opaque green colour.

As to the systematic position of the above species, Pando-
rina belongs, of course, to the Volvocinee ; Clathrocystis is
doubtless referable to the same group as Pulmella cruenta, and
therefore to the family of true Palmellacee, which will require
to be kept apart from Protococcus, and similar forms, on
account of the absence of zoospores. Apiocystis must remain
for the present in the heterogeneous assemblage which in-
cludes Protococcus, Gleocapsa, &c., which require much
more study before they can be satisfactorily classified.

Wenuam, on Illuminating Opaque Objects. ay)

On a Mernop of Ittuminating Opaque Ossecrs under the
FTighest Powers of the Microscorr. By F. H. Wennam.

(Read March 26th, 1856.)

Repeated experiments have shown, that it is a matter of
extreme practical difficulty to contrive any method of con-
densing light directly down upon an object, when viewed
under an eighth or twelfth object-glass of large aperture. In
the first place, the close proximity of the front lens and its
setting, will only allow a thin conical dise of light, to find a
passage towards the object, at an angle of seldom less than
100°, or at an obliquity far too great to be practically useful ;
and secondly, when the object is covered with thin glass, con-
siderably more than half the light will be lost by the reflection
from the surfaces, the rays from which enter the microscope,
and*occasion an amount of glare and fog sufficient to obscure
the object; for these reasons [ think that there is but little
chance of obtaining any useful result in this direction.*

The methods that I now bring before the Society are based
upon an entirely different principle, which is not applicable
to dry objects, but only to those mounted either in Canada
balsam, fluid, or any other refractive medium. An experience
of nine months warrants me in the assurance of its complete
success, as a means of investigation—objects being brilliantly
illuminated in a jet-black field, with an objective of 170° of
aperture or more.

‘The principle of operation consists, in causing rays of light
to pass through the under side of the glass slip upon which
the object is mounted, at the proper angle for causing total
internal reflection from the upper surface of the thin cover, which is
thus made to act the part of a speculum, for throwing the light
down upon the under-lying objects, immersed in the balsam or
fluid.

As there will be no total reflection from the planes of a
parallel plate of a refractive material, it is necessary to adopt
some method for allowing the rays to enter the medium at
such an angle as to cause total reflection from the upper sur-
face. There are many methods of effecting this; those which
I now describe I have found to be the most practicable and
useful: a,a, fig. 1, is a glass slide containing objects mounted
in balsam; 8, thin glass cover; ¢c, is a right-angled prism

* Since the above, Mr. Ross has shown me his ingeniously-contrived
Leiberkuhn, applied to the highest powers for illuminating uncovered
opaque objects, and which performs most admirably ; to my mind un-
doubtedly proving the fact, that the minute scales from the wings of
butterflies, &c., are perfect cellular structures.

56 Wenuaw, on a Method of

cemented on to the under surface of the slide with Canada
balsam; d, is an Amici prism for condensing and directing
the rays into the prisin ¢; e, is a large bull’s-eye condenser
placed with its convex side toad thie lamp.

Fig. 1

Making ample allowance for all possible differences of
refraction in the slide, balsam, and cover, the angle of total
reflection for the mean anced | ray, will vary from 40° to
45° from the perpendicular—at any rate it will never exceed
the latter degree ; consequently for this reason I consider the
right-angle prism the most convenient for most purposes, as the
rays may be passed perpendicularly through its surfaces with-
out any trouble arising from refraction.

The mode of action illustrated by the diagram is simply as
follows: the rays from the luminous source are first collected
and converged by the large bull’s-eye lens e, and then further
condensed and directed upwards by the Auwies prism d; they
next enter the surface of the right angle prism e, and pass
directly onwards till they reach ‘the upper side of the thin
cover, from whence they are totally reflected down again,
forming a brilliant surface of light, which will of course illu-
ininate any small bodies immersed in the balsam just below.
If the cover is clean and free from scratches, not the smallest
portion of light from the luminous source will find its way
through. The view of the objective will be unimpeded, and
the field perfectly black. Another way of causing the light to
enter the prism, is by means of a parabolic condense rr, adjusted
as under ordinary circumstances ; the light will in this case
enter the two faces of the prism at the same time, which is
some advantage ; it must be sufficiently small to have some

Illuminating Opaque Objects. 57

play in the cavity at the apex of the paraboloid ; if the right-
angled faces are one quarter of an inch square, it will perform
very well. The objection to the plan just described is the
necessity of having a separate prism for every object, which,
though of advantage in some remarkable and peculiar cases, is
not necessary for all. Fig. 2 is more universal in its appli-
cations ; aa is a thin plate of brass, }, a right angle prism let
in exactly flush with the upper surface; any small objects

Fig. 2.

such as animalcules, Diatomacee, pollen, &c., must be laid
upon the prism with water, and covered with thin glass; total
reflection will then occur from the uppermost surface, in the
same way as in fig. 1, and illuminate the objects in the fluid.
Any ordinary plane slide containing objects mounted in
balsam may be placed upon the plate and prism, first inter-
posing a drop of water. It is almost unnecessary to remark
that if this, or some other fluid is not interposed, the rays will
all be reflected from the back of the prism itself, instead of
passing onwards into the slide.

Fig. 3 is another method; aa is a glass slide—under this
is cemented with Canada
balsam a lens, 0, nearly
hemispherical, with a seg-
ment removed so as to
leave the thickness equal
to about one-third the dia-
meter of the sphere. The
flat facet of the lens is
blackened. The radius of
curvature should be about
two-tenths of an inch: the
use of the blackened facet
is to exclude all rays below
the incident angle of total .
reflection. This lens is intended to be used in conjunction
with the parabolic condenser, in the manner represented by the
figure. The rays from the parabola pass through the surface of
the lens in a radial direction without refraction, and proceed
till they reach the upper surface of the thin glass cover, where
they are totally reflected and converge upon the object; the

58 Wenuam, on a Method of

cover in this instance acts precisely the part of a Leiberkuhn,
with the advantage of more perfect reflection.

A lens of this description may be let into a thin plate of
brass as in fig, 2, and used in the same way as an aquatic
holder, the parabolic condenser always being used for concen-
tratng the light. When-a slide containing balsam-mounted
objects is placed above the lens, instead of using water, it is
preferable to employ turpentine, or oil of cloves ; the refractive
index of the latter being nearly the same as crown glass. The
reason for introducing this agent is because light impinging
upon the polished plane between a greater and a less refractive
medium, will always suffer total reflection at the surface of
the former, at a given angle dependent upon the relative
refrangibilities. If water is used, the angle of the illuminating
pencil will be limited to about 160°; above this, all rays will
be reflected down again by the flat surface of the lens, and
lost, as shown by fig. 4; aa represents the glass slide, with

objects in balsam ; } is a hemispherical lens placed underneath
the slide, with water interposed ; ¢ c, rays which pass onwards
to the top plane of the thin glass cover, to be reflected down
again upon the object: the dotted lines, dd, are the portions
of the illuminating pencil, that will be lost by being reflected
from the flat surface of the Jens—of course if a medium of
nearly the same refractive power as the glass is used, ‘such as
oil of cloves, all this light will be transmitted and rendered
available,

Another variation in this principle of illuminating opaque
objects, is that illustrated by fig. 5: a is a small paraboloid of
solid glass with a flat top. A black stop, 4, of the same
iliameter as the apex, is fixed at the base of the parabola, for

Illuminating Opaque Objects. 59

the purpose of stopping out direct rays. This paraboloid is

set in a ring, which is screwed underneath a flat brass plate,

so as to bring the upper plane surface of the glass exactly
level with that of the plate in the manner shown by the figure.
The parabola must be sufficiently short to prevent any rays

from passing within the angle of total reflection relative to the
flat top—or the paraboloid may be cut off at the ae in the
curve intersected by an angle of 45° drawn from the focus.

If a powerful series of parallel rays be sent into the base of
this paraboloid, not any of the light will find its way through
the upper flat surface. The whole will be reflected down
again into the body of the glass. If now a piece of thin glass
is placed on the top, with a drop of water, the greater portion
of the illuminating pencil will be fran aie to the upper
surface of the cover, and from thence totally reflected, illumi-

nating any small objects contained in the fluid. Glass slides
containing balsam objects may be placed on the apex of the
paraboloid, using an intermedium of turpentine, camphine, or
oil of cloves, in preference to water, This same reasoning also
applies when small objects are viewed directly in fluid, by
being laid on the flat top of the paraboloid, and covered with
thin glass. When the nature of the substances will admit of
it, for the purpose of obtaining greater intensity of illumina-
tion, they should be placed in turpentine or oil of cloves; in
this case the whole of the light will be reflected from the top
surface of the cover—no separate reflection taking place from
the upper plane of the paraboloid, as with water. In using
this instrument, all that is required is to throw direct light
into the parabola, by means of the concave mirror,

Having now described some modifications of this principle
of illuminating opaque objects, as most especially adapted for
the highest powers, numerous experiments will Justify me in
saying a few words as to the effect. The light may be ob-
tained of any required degree of intensity, and the field per-

60 WennAm, on the Vegetable Cell.

fectly black, with objectives of the most extreme aperture ;
some Diatomacee mounted in balsam, are shown with a degree
of beauty and delicacy, that I have never seen equalled, and
from the lights brilliantly illuminating the prominences on the
surface, many of them wear an entirely different appearance to
the same objects seen as transparencies, and from the absence
of all irregular refraction and colour, and the purity of the
vision, the mind is impressed with the fact, that we are viewing
them under their true features, as cellular structures, and in
some instances displaying such a singular arrangement and con-
figuration of markings, in cases where I had not even suspected
them to exist, that I shall on a future occasion give some
illustrations of them. It must not, however, be expected that
all the Diatomacee can be seen by these methods, for some of
them, when mounted in balsam, are so exceedingly translucent,
that they will not hold a sufficient quantity of light, to be
viewed as strictly opaque objects.

For this method of illumination, the greatest nicety is
required in the adjustment of the object-glass, the slightest
defect in this causing milkiness and indistinctness of vyision—
indeed so particular is the care required in this respect, that a
different adjustment is sometimes necessary for various parts
of the same object, in a case where it lies in an inclined
position in the balsam.

With regard to the relative merits of the three methods that
I have mentioned ; for those who are already possessed of a
parabolic condenser, the preference is most decidedly to be
given to the hemispherical lens, fig. 4, set in a very thin plate
of brass, but the truncated paraboloid, fig. 5, is by itself a
most convenient piece of apparatus, readily applied and easily
managed, forming a most useful adjunct to the other.

On the VEGETABLE Ceti. By F. H. Wennam.
(Read May 28th, 1856.)

In the ‘ Annals of Natural History’ for May, 1856, there is a
notice, by Professor Henfrey, relating to my paper on ‘ Cell
Development,’ published in the ‘Quarterly Journal of Micro-
scopical Science’ for Jan, 1856. I prefer making my reply
through the medium of the same Journal, which is accessible
to all whom the subject may concern.

The notice commences by saying :—‘t The essay contains
internal evidence of the author’s want of familiarity with the
subject treated.” It does, in all probability, contain irregu-
larities and omissions which may possibly be exeused in an
inexperienced writer on these particular subjects. I pretend

Wenuam, on the Vegetable Cell. 61

to be nothing more than a sincere searcher after the truth,
uninfluenced by motives of ambition or notoriety ; and it is
not fair that I should be criticised according to the same
rigid rules which would be applicable to an established pro-
fessor. As regards “ want of familiarity with the subject,”
I can only say, that for years past I have examined the deve-
lopment of the vegetable cell, and have been trying, without
success, to reconcile the facts that I have observed with the
written statements of Mr. Henfrey; for it is to these, or such
as have appeared under his sanction, that I have made the
most particular reference. ‘This is my excuse for not viewing
these things through the medium of Mr. Henfrey’s eyesight,
and for falling back upon my own judgment ; and I trust that
I may be pardoned for so doing. Even to this hour the cell
theory is by no means a settled question, and I would advise
those engaged in this study to form their ideas less upon a
groundwork of contending theories, and apply more diligently
and directly to the book of nature for information.

It is to be regretted that any remarks should give rise to
this form of reply, so directly out of the course of correct
scientific discussion. I will now proceed to notice Mr. Hen-
frey’s objections, which are scanty enough. He first says, in
reference to me :—“ The objects selected were unfavourable,
and not favourable as he imagined ; for young leaves of most
flowering plants, in the stages figured by him, are not flat
plates, but cones, or at all events solids having more than
one thickness of cells in all three dimensions ; therefore the
view is confused by one layer lying behind another.” In
reply to this I may say, that if Mr. Henfrey had condescended
to read my paper before thus perverting my meaning, he would
find these subjects described as “ cellular-cones,” or “ nodules
of protoplasm filled with cell-cavities ;” so that this objection
must at once fal] to the ground: and to avoid the delineation
of that confusion he mentions, I had drawn directly with the
camera lucida the top layer of cells only, and any error in form
and position is a trifling one, occasioned by the object being
slightly flattened in the compressor.

Mr. Henfrey further remarks :—‘ But even in the leaves
of Anacharis the application of dilute sulphuric acid and
solution of iodine suffices to render the structures clearly dis-
tinguishable, as quite different from what is represented in
Mr. Wenham’s drawings.” No doubt of it! I believe that
there are but few recent vegetable structures that would
submit to such treatment unchanged. I have tried numerous
experiments with these and other re-agents, but ceased to place
much confidence in them for the investigation of very young

62 Wennam, on the Vegetable Cell.

cells ; for, though they are most useful for testing the transi-
tion stages between protoplasm, starch, and cellulose-layers,
Se; they are extremely prone to develop an appearance of
membranes and organisms that do not really exist. I much
prefer, when the case will admit of it, to view the structure
and note the successive stages of development under natural
conditions. Iam, however, far from wishing to disparage the
valuable test referred to. The effect of sulphuric acid and
solution of iodine, in the young cells in the cases in question,
is to cause the cavities in the formative plasma to become
more distinctly apparent, as perfectly clear spaces, containing
nothing else but a watery fluid. The objection that I have
sometimes found in using it is, that in the boundary of a
consolidated plasma, known to be homogeneous, it is apt to
develop the appearance of layers, or zones, not arising from
cellulose deposits, but caused by the grades of chemical
action of the test. When young cells contain but a small
quantity of contents, another fallacy may arise, from the
application, for they become drawn together in the centre of
the cavity, appearing as a ball of nucleus,

As a further explanation, which must be considered supple-
mentary to my former paper, I have now some additional
remarks to make on vegetable cell development.

The basis of a cellular structure in its first stage,—consist-
ing of a membranous sac filled with an uniform plasma, or
mass of formative material—may be termed by some, “ the
primordial cell ;” but in my view improperly, for the external
membrane is merely protective, it exerts no active influence
upon, and is unconnected with the subdivision, or cellulation
of the contents, and, taken as a whole, has none of the func-
tions of an individual cell.*

Now we have here a vesicle filled with formative material,
ready to break up into a group of cells. Those who have
examined for themselves with the requisite degree of care
must recognize a simultaneous development,t numerous rudi-

* When the cuticular envelope, containing the uniform plasma, is
ruptured under water, the protoplasm sometimes escapes as a globule,
which speedily becomes filled with vacuoles. These rapidly enlarge and
increase in number, till the whole becomes spread out and diffused in the
fluid. The tunic, or envelope of young cells, does not at first, in all cases,
possess an uniformity of surface ; for, in many plants it is spinous, or
covered with tubercules, at its earliest stage ; these are the rudiments of
hairs. It is remarkable at what an early period they are perfectly deve-
loped, even before a detinite or complete cellulation of the plasma, that
they have sprung from, has taken place ; some of the hairs being already
jointed, and showing sap-currents in their cells.

+ When the bark is stripped from the growing branches of exogenous
plants, early in the spring, the surface of the wood is covered with a slimy

Wennuam, on the Vegetable Cell. 63

mentary cell-cavities appearing spontaneously throughout the
mass at the same time, and increasing independently of each
other; in every one the inner lining of each space in the
formative protoplasm becoming hardened into a membranous
layer, which may be readily proved, as the unconnected cell-
sacs can be washed out of the containing plasma and isolated.
The “ vacuoles” are rather apt to take their rise from the
larger particles contained in the plasma, but I believe that
this is only a mechanical and not a vital condition, for it is
equally certain that a large number of them form themselves
apparently without any starting point whatever. In Anacharis,
and many other plants, these cells, in the first stage of their
existence, are simple membranous sacs, containing nothing
else but a limpid, watery fluid, and a few very minute granu-
lar bodies adhering to the cell-wall—and here is a point at
issue. It is maintained that cells, even in their very earliest
stage, contain an active nitrogenous layer lining the interior
of their cavities—the so-termed “ primordial utricle.’ My
own observations cannot confirm this; and, indeed, reasoning
independently of the evidence of eye-sight, it seems an
anomaly to expect a detached portion of a material to be
enveloped in a cavity of its own substance, before any limitary
membrane is completely formed to prevent their coalescence.
Neither can it be set down as a general rule, that new cells
are commenced singly. around a collection of solid contents,
for “ vacuoles” are to be seen of the minutest size, which are
afterwards expanded, so as to become perfect cells in all
respects ; unless in this case it is assumed that the formation
takes place around invisible contents.

As I have before stated, it is not until the membrane of the
sac is completely formed, that protoplasm is found within the
cell; this is rapidly followed by the deposit of internal

film of protoplasm, in a free state; if this is scraped off it will be found
to contain transitional cambium cells, dotted ducts, &e., in all stages of
development. ‘The formative plasma is mostly deposited in the form of
strips, in the grooved surfaces of the bark and wood, and there rapidly
resolves itself into a row of cells, or hardens into a fibre, according to the
influences of local conditions, or the size of the matrix. These cells are
not formed by the division of older ones, but arise directly from the
simultaneous cellulation of the formative plasma, in the manner that I
have explained in other instances.

From the light colour of the substance it is a difficult matter to investi-
gate the young cellular deposit, as an opaque object ; but after the surface
has dried, an impression may be taken with black sealing-wax, which will
also sometimes bring away some of the young cells in course of formation,
and afford a more satisfactory view of the cell stages and arrangement,
using a Leiberkuhn for illumination.

64 WenuaM, on the Vegetable Cell.

secondary layers, and the appearance of other constituents,
as starch, chlorophyll, &e.

The sooner the term “ primordial utricle,” as applied to
the active nitrogenous fluid, or protoplasm, flowing round the
interior ofthe cell-cavities, is discarded the better, for a clear
understanding of its all-important properties as the formative
principle. If even a viscid fluid can be endowed with the
properties of a membrane, it is not at all times so in this
case, as it frequently collects in the form of clots, or nuclei
(as some might term them); thus changing its name and
appearance perhaps several times during the course of a day.

The specimens drawn for illustrating my last paper origin-
ated in a plasma so homogeneous and free from all extraneous
matters, that the cell-cavities were clear from first contents ;
in fact, this is mostly the case with Anacharis and some other
aquatic plants ; the cellulation occurring in a mass of proto-
plasm nearly pure ; but this is not so in “other instances.

What I have already said of cellular formation might serve
as a guide to the principle to which my investigations have
led me, but it may now be proper to notice some frequent
variations, which at first sight might not appear reconcilable
to my views: I refer to tissues originating in a mass of cells,
not hollow at their commencement, but with their cavities
completely filled with contents (and hence I have always
hesitated in making use of the general term “ yacuoles”’).
This condition is easily observable in some leaves and germi-
nating seeds, where the formative substance contains a larger
quantity of extraneous matter; under such circumstances the
process of cellulation is in no way different, for relieving the
mind from the task of attempting to reconcile the theory of
the subdivision of an unity (and the relationship of “ mother
and daughter cells”), and admitting the principle of a simulta-
neous development of cells, the denser granulated material of the
original plasma, in its first stage of cellulation, is shown to
arrange itself in the form of irregular squares, trapeziums, or
oblong figures, partitioned off by thick divisions of more
transparency and consistency. This is the true protoplasm,
which has separated from its solid admixtures, or expanded
from centres, as it were, to form the cell walls, a process to
which Dr. Carpenter has so appropriately applied the term
‘differentiation ;”’* but it must not be supposed that these

* This term is also explanatory of the formation of the simplest types
of shell, which have arisen from a plasma containing calcareous matter.
The ‘‘sarcode” (analogous in vital properties to vegetable protoplasm)
having separated into somewhat irregular divisions, and formed a mem-
brane between the nucleated and consolidated calcareous matter, producing
a rude cellular structure. In some more perfect developments of shell

Wenuam, on the Vegetable Ceil. 65

rudimentary walls, or rather septa, become one uniform and
continuous solid—the true cell wall is still formed in the
interior of each cavity, with the appearance of being moulded
upon the mass of contents, and when the membrane has
acquired consistency, the proper cell constituents arise within,
from external absorption as in former instances. The cells
may now be washed out from the intervening plasma in
which they are imbedded, as separate sacs just in the same
way as I have described before.

The expanding action of the living protoplasm, may be
seen in actual operation during the conjugation of the
Desmidiee—a process that I have always watched, with never-
failing interest. When the two masses of endochrome are
ejected, they are not bounded by any limitary membrane as
some seem to suppose, but unite at first oftentimes in the
form of a rugged mass. All the intervening protoplasm now
separates from the general mixture, and forms an external
sheath, which hardens into a membrane—the cell wall of the
unicellular sporangium.* I bring this forward again, because
the expansive effect of the protoplasm, as seen to take place
here, will illustrate the action in the associated cells in
question, when filled with contents, by considering each cell
in the formative plasma for the time being, as a separate and
independent organ.

If now one system of cells are first formed with empty
cavities, and another with more or less of primary contents,
the question arises, what ought to be the physiological differ-
ence in favour of the subsequent vital welfare and develop-
ment of the latter? As far as my investigations have gone I
cannot say that the full cells appear to differ much in growth,
or derive after benefit from the circumstance of their first
replete condition, the well-doing of the cell still depending
upon external conditions ; but without going so far as to state

structure, there seems to be a beautiful combination of this vital action, in
conjunction with definite chemical arrangement, or a crystallization of the
calcareous deposit, giving rise to very regular and perfect cellular forms,
and prismatic structures. It would be a very interesting inquiry to ascer-
tain how far these two forces act together in harmony, in forming regular
cell arrangements in other departments of the animal and vegetable king-
dom. ‘This would be an investigation in which the polariscope would be
extremely serviceable.

* In some of the Desmidiece and Algce, when the endochrome or con-
tents of one cell are forced out, by the application of gentle pressure, into
the water, the first action is somewhat similar to that which takes place
during conjugation. The protoplasm separates from the other consti-
tuents, and is determined outwards as a complete envelope, the mass ac-
quires a spherical shape, and remains so for many hours, but no consis-
tent exterior membrane is ultimately formed ; all vital action ceasing at
this point, the mass always proving barren.

66 WenuaM, on the Vegetable Cell.

that the primary contents are useless for the purposes of
nutrition, [ will merely mention that some recent and most
valuable practical researches, made by an independent ob-
server (and which I trust he will shortly bring before the
public), have proved that extraneous matters may be conveyed
into the mass of the formative plasma, and substituted for the
contents of the primary cells, without interfering with the
growth, and of such a nature as to afford no nutriment to their
tissues.

In conclusion I beg to inform the Society, that though the
microscope has led me to take up particular views of cell
development, I do not profess to write a complete essay on
the subject. I will, however, remark, that it is still quite a
new field for investigation, for all the controversies and con-
tending theories that for years past have appeared on this
theme have done but little towards the enunciation of a
simple system of laws. As cell formation undoubtedly takes
place, in various grades of complexity, the lowest and highest
being widely different in their mode of production, in order
to simplify this most important branch of science, I would
venture to suggest, with all due deference, the possibility of
classifying the subject, by arranging it in heads or depart-
ments, or to make myself understood, say as follows :—

1. Spontaneous appearance of membranous cavities in
a primitive plasma, or simple differentiation.

2. Cell formation by self-division, or the conjunction of
definite membranes or utricles.

3. Cells requiring special organs for their production.

4, Allied phenomena, &c.

If this were accomplished it would save some amount of
confusion; much of what is already known might be arranged
under such heads as these. In the most highly organised
plants, it is probable, that all these modes of cell formation
separately exist, in various organisms.

It is to after influences, or vascular bundles arising from
the parent stem, that the proportions of symmetry and form
are conveyed to the embryo cellular mass, dividing, distribut-
ing, or increasing it according to its destined condition. At
the time that these vessels and ducts begin to force their way
through the young assemblage of cells, these differ so much
in both individual form and arrangement, as to be typical in
nearly all cases of the most excessive irregularity (the embryo
leaves of the vine may be taken as an average example), and
is utterly irreconcilable with the idéa that the cavities or cells
originate from the regular division and subdivision of pri-
mordial cells.

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