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No. XXXI. APRIL, 1860. Rica da.

QUARTERLY JOURNAL

OF

MICROSCOPICAL SCIENCE:

Che Microscopical Society of ondon.

EDITED BY
EDWIN LANKESTER, M.D, F.RS., F.LS.,

GEORGE BUSK, F.RBCSE, FBS, F.LS.

: WITH WOODCUTS AND LITHOGRAPHIC ILLUSTRATIONS.

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| LONDON:
JOHN CHURCHILL, NEW BURLINGTON STREET.
MDCCCLX.

;. Adlard,) , [Bartholomew Close.

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TRANSACTIONS OF THE MICROSCOPICAL SOCIETY

GH
CONTENTS OF No. XXXI ‘Q
Va
V

OF LONDON.

PAGE

List of Diatomacee occurring in the Lee ey | of Hull. By
Grorce Normay, Esq. : 59

On the Reproductive Process in the Contenido (with pat of Plate
VI). By T.C. Druce, Esq. ; 71
Report of Annual Meeting—The President’s Aeldies ; » wok.

On the Amceboid Conditions of Volvox Globator. By J. Braxton
Hicks, M.D. Lond., F.L.S., &. ‘ . 99

A Monograph of the Genus Asterolampra, spaiddias Asteromphalus aa
Spatangidium. By R. K. Grevitie, LL.D., F.R.S.E. &e. . 102

On the Structure of Carduella cyathiformis. A contribution to our
knowledge of the Lucernariade. By Prof. Aruman, F_R.S., &. &c. 125

On the development and Structure of the Diatom-valve. By G. C.
Wattuicn, M.D., F.L.S. . F ‘ : 2-199

JOURNAL OF MICROSCOPICAL SCIENCE.

ORIGINAL COMMUNICATIONS:

On American Diatomacee. By ArtHur M. Epwarps, Esq., New

York, U. 8S. 3 : ; : . 127
TRANSLATION:
Atmospheric Micrography. Observations on the Corpuscles suspended
in the Atmosphere. By M. Poucurt : ; . 1380
NOTES AND CORRESPONDENCE . eee 2 Gee 2 ae
PROCEEDINGS OF SOCIETIES ; te | hig ag aie a
ZOOPHYTOLOGY.. yin Ades : ; . 143

TRANSACTIONS.

List of Diatomace# occurring in the neighbourhood of Hull.
By Georce Norman, Esq., Hull

(Communicated by Dr. Lankester. Read January 11th, 1860.)
a

Fottow1ne the example set by Mr. Comber, in his excellent
“TJist of Diatomacez, of the neighbourhood of Liverpool ”’
(Transactions of the Historic Society of Lancashire and
Cheshire.—Vol. xi.), I have, in the following Paper, attempted
to give as complete a list as possible of the Diatomacez of
Hull and neighbourhood.

In so domg, I have not been so much influenced by the
desire to make the paper of so much interest to Diatomists in
general, as to compile a list which will be found serviceable
to those who may wish to study and collect the forms occur-
ring in this particular locality. Apart from this, however, the
list may have its use (as far as it goes) in being a record of
the local distributions of these beautiful forms.

On referring to Mr. Comber’s list, it will be seen, that
Liverpool and neighbourhood furnishes 257 species—a large
number certainly, but falling considerably below the number
detected in this locality. This may be partly owing to the
area included in my list, beimg somewhat larger than the
limit taken by Mr. Comber; nevertheless, I may fairly say,
that the neighbourhood of Hull is peculiarly rich in Diato-
mace ; furnishing, as it does, nearly 400 species.

It may be here remarked, that (with the exception of one
haul off Flambro’ Head) dredgings on our coast are untried.
Sand gatherings which have yielding Dr. Donkin and others
so many novelties have also been scarcely tried—These two
methods, if properly carried out, would in all probability con-
siderably increase the number of species.

It is also very likely that I have overlooked many forms
which would otherwise have been recorded, had the time of

VOL. VIII. 3 a

60 Norman, on Diatomacee.

observation extended over a longer period of time. ‘The
following species were collected by myself (with the few ex-
ceptions I have mentioned) within the short period of little
more than three years.

It may perhaps be objected to, that species have been in-
cluded which strictly speaking have not occurred in this
neighbourhood. JI allude here to the various forms collected
from Ascidians taken from Oysters, dredged some 30 miles
from the Humber mouth ; but when I state that these Asci-
dians may always be found on Oysters in the Hull market
during the winter months, I think the objection is overruled.
Again, I have thought proper to include one or two species
collected in the Docks from the bottoms of vessels recently
arrived from abroad. In so doing, my object has been to
point out this source for many interesting forms, and to sti-
mulate others to examine vessels arriving in our various ship-
ping ports. Diatoma hyalinum and Hyalosira delicatula have
occurred to me copiously in such localities.

I have already stated, that—with few exceptions—the
species enumerated in the following list have been collected
and identified by myself, consequently I alone am responsible
for the correctness of the same. ‘

The exceptions are the species and localities furnished by
Mr. Robt. Harrison, and Dr. Munroe, to whom my best
thanks are due.

Ji will be seen that I have included the Genera Rhizoso-
lenia, Dicladia, Chetoceras, Syndendrium, and Bacteriastrum,
which may or may not with propriety be considered as true
Diatomacezee. They are however, in my opinion, so closely
allied that I have not hesitated to admit them.

Epituemia, Kiitzing.

Fi. turgida, Sm.—Not wocommon. Risby Pond. Peat Deposit,
Hornsea. Plentiful in a pond, Stepney Lane.

i. Westermanii, Sm.—Rare. North Humber Bank, Dr.
Munroe.

i. Hyndmanii, Sm.—Rare. Peat Deposit, Hornsea.

Ei. granulata, Kiitz.—Rare. Hornsea Mere. Hornsea Deposit.

EL. Zebra, Kiitz.—Not uncommon. Hornsea Meer. Driffield.
River Hull, Wawne.

E. Argus, 8m.—Rare. Hornsea Deposit.

Ei. alpestris, Sm.— Rare. Hornsea Deposit.

E. proboscidea, Kiitz.—Local. Tetney Lock. Hornsea De-
posit.

E. Sorex, Kiitz,—Rare. Pond in Stepney Lane, copious.

Norman, on Diatomacee. 61

E. Musculus, Kiitz.—Not uncommon. Brackish marsh, Tet-
ney Lock. Timber Pond, Victoria Dock. Ditch near
Stoneferry.

E. constricta, Sm.—Rare. Brackish marsh, Tetney Lock.
Brackish Ditch near Stoneferry. North Humber Bank,
Dr. Munroe.

E. gibba, Kiitz—Not unfrequent. Risby Pond. Driffield.
Brackish pond near Tetney.

E. ventricosa, Kiitz.— Not uncommon. Risby Pond. Brack-
ish marsh, Tetney Lock. Salt-water Ditch, Stallingbro’.
River Hull, Wawne. MHornsea Peat.

E. marina, Donk.— Rare. Sands, Hornsea.

CymBe.ta, Agardh.

C. Ekrenbergu, Kitz.— Not uncommon in fresh water.
Hornsea Peat. Cottingham. Spring Ditch.
C. cuspidata, Kiitz— Not uncommon, but never abundant.

Saltersgate. Harrogate. Frequent in gatherings,
Cottingham.

C. affinis, Kiitz—lLocal. Abundant in a gathering near
Harrogate.

C. maculata, Kiitz—Frequent. Pure, in a ditch running
from Anlaby to Hessle Road. Beverley. Cottingham.
Haltenprice. Reservoir Waterworks.

C. Helvetica, Kiitz.—Rare. Rocky stream, Saltersgate. Spring
Ditch. Market Weighton Canal.

C. Scotica, Sm.—Raye. Rocky stream, Saltersgate. Ditch,

Cottingham Road.
. ventricosa, Kiitz.—Not uncommon. Pond, Skirlaugh.
Inglemire Lane, near Cottingham, pure. Benningholme.

Q

Ampuora, Ehrenberg.

. ovalis, Kutz—Common in almost every fresh-water
gathering ; more rarely in brackish water.-

. affinis, Kiitz.— Not unfrequent in brackish water. Ditch
near Stoneferry. Humber Bank. Tetney.

. hyalina, Kiitz.—Frequent. Humber. Pure in a salt-
water pool, Grimsby.

. salina, Sm.—Not unfrequent. Victoria Dock Timber
Pond. River Hull, near Stoneferry.

. tenera, Sm.—Common in salt-water Pools and Ditches.
Dairycoates under Railway arch. North Humber Bank,
pure. River Hull, near Stoneferry.

. costata, Sm.—Rare. Behind the Garrison, Dr. Munroe.

. minutissima, Sm.—Fresh water. Cottingham. Beverley
Parks, near Woodmancy. Springs, Newbald.

mB hoo

EN

62 Norman, on Diatomacee.

boi ik fi

. n. 8. with capitate extremities. Growing on wall in a Fern
and Orchid stove.

qguadrata, Greg. —Rare. Ascidian gatherings.

arenaria, Donk.—Rare. Sands, Hornsea.

. ittoralis, Donk.—Rare. Sands, Hornsea.

. crassa. Greg,—Rare. In Ascidians.

Cocconrts, Ehrenberg.

. Pediculus, Ehr.—Very common in most fresh-water

gatherings. Pure, Cottingham Beck, on Cladophora
Waterworks reservoir. Beverley. River Hull. Cot-
tingham, &c.

. Placentula, Ehr.—Very frequent. Cottingham. Halten-

price. Wawne. Pure on Cladophora, Harrogate. Water-
works reservoir.

C. Thwaitesii, Sm.—Rare. Ditch, Cottingham-road. Springs,

Newbald.

C. Scutellum, Ehr.—Common on Cladophora rupestris. Filey.

Flambro’ Head. Stomachs of Ascidians.

C. diaphana, Sm.—Rare. Hornsea Deposit. Brackish ditch,

C.

Marsh Chapel.

Coscinopiscus, Ehrenberg.

. minor, Ehr.—Rare. Ascidians.
. minor, Kiitz.— Rare. Inaslide from the Humber gathered

by Dr. Redfern in 1853, and sent to me by Professor
Arnott.

. radiatus, Ehr.—Common in Ascidian gatherings. Dredg-

ings off Flambro’ Head. Rare in Market Weighton
Canal. Rare in Reservoir Waterworks, where the salt
water unfortunately sometimes has access.

eccentricus, Ehr.—Very common in Ascidian gatherings,
often very pure.

C. Concinnus, Sm.—Frequent in Ascidians, sometimes very

large.

C. perforatus, Ehr.?—Ascidians. Very rare.

C. ovalis, Roper.—Very rare in Ascidian gatherings.

C. Normani, Greg.—F requent in Ascidian gatherings.

C. Labyrinthus, Roper.—Very rare in Ascidian gatherings.
C. centralis, Ehr.—F requent in Ascidians.

E

Evropiscus, Ehrenberg.

. Argus, Ehr.—Not unfrequent in Ascidians. Dredgings
off Flambro’ Head.

Norman, on Diatomacee. 63

E. fulvus, Sm.—Very plentiful and fine im Ascidians.

E. crassus, Sm.—Ascidian gatherings. Sands, Hornsea.
Stoneferry.

E. sculptus, Sm.—fRare. Ascidian gatherings.

E. tesselatus, Roper.—Very abundant and fine in Ascidians,
sometimes nearly pure.

E. Ralfsti, Sm.—Rare. Ascidian gatherings.

Actinocycivus, Ehrenberg.

A. undulatus, Kiitz.— Very frequent in Ascidian gatherings.
Stoneferry, rare. Dredgings Flambro’ Head. Filter
Waterworks, rare.

TricERATIUM, Ehrenberg.

T. favus, Ehr.—Very rare in Ascidians. Single frustule,
Walls of Victoria Dock.

T. alternans, Bailey.—Frequent in Ascidian gatherings.

T. striolatum, Ehr.—Rare in Ascidians.

T. armatum, Roper.—Very rare in Ascidians.

T. undulatum, Brightwell.—Very frequent in Ascidians.

CycLoretta, Kiitzing.

C. Kiitzingiana, Thwaites—Very common in fresh and
brackish water. Spring Ditch. Cottingham. Tetney.
Stoneferry. Market Weighton Canal. Wawne.

C. minutula, Kiitz.—F requent in the Hornsea Deposit.

C. operculata, Kutz.—Frequent in clear Ditches. Spring
Ditch. Cottmgham. Ripley. Pure in a Drinking
Trough for Poultry.

C. rotula, Kiitz.— Rare. Market Weighton Canal. Hornsea
Deposit.

C. punctata, Sm.—Very copious and fine in a gathering made
in the Market Weighton Canal, near the River Foulney,
attached to Myriophyllum and Potamogeton.

C. Dallasiana, Sm.—Rare. In a ditch running from Stone-
ferry to Sutton.

CampyLopiscus, Ehrenberg.

C. costatus—Frequent. Spring Ditch. Plentiful in an Iron
spring, Haltenprice. Springs, Cottingham. Springs,
Newbald. Market Weighton Canal. Hornsea Deposit.

VOL. VIII. k

64 Norman, on Diatomacee.

C. Hodgsonii, Sm.—Not unfrequent in a Dredging made off
Flambro’ Head.

C. spiralis, Sm.—Not unfrequent in boggy places. Iron
spring, Haltenprice, copious. Boggy place, Skirlaugh.

C. cribrosus, Sm.—Not unfrequent in salt-water Pools and
Ditches, Humber Banks. Market Weighton Canal.
Marfleet.

C. parvulus, Sm.—Rare. Ascidian gatherings.

C. decorus, Bréb.—Rare. In an Ascidian gathering.

SURIRELLA, Turpin.

R

. biseriata, Bréb.—Not uncommon in fresh and even in
brackish water. Cottingham. River Hull. Market
Weighton Canal. Wawne Ferry.

S. linearis, Sm.—Not unfrequent in fresh-water localities, but
always sparse. Cottingham. Beverley Parks. Wawne
Ferry. Hornsea Deposit. Market Weighton Canal.

turgida, Sm.—Very rare in brackish water. River Hull,
northward of Stoneferry. North Humber Bank, Dr.
Munroe. ;

S. splendida, Kiitz— Not frequent. Spring Ditch. River

Hull, near Stoneferry. Market Weighton Canal.

S. nobilis, Sm.—Not unfrequent. Hornsea Deposit. Cot-
tingham. Market Weighton Canal. Stoneferry, &c.

S. striatula, Turp. — Not unfrequent in brackish water.
Stallingbro’. River Hull, near Stoneferry. Humber
Banks. Market Weighton Canal.

S. Gemma, Ehr.—Very frequent in salt-water Pools. North
Humber Bank. River Hull, Stoneferry. Quite pure at
Patrington. Breakwater near Hessle. Pure Humber
Banks, Mr. Robt. Harrison.

S. fastuosa, Ehr.—Rare. Ascidian gatherings.

S. Craticula, Ehr.—Very rare in the Hornsea Peat Deposit.

S. ovalis, Bréb.—Not unfrequent in brackish water. Stal-
lingbro’. Small Ditch near River Hull, above Stoneferry.
Hornsea Deposit. Ditch running from Anlaby to
Hessle Road.

S. panduriformis, Sm.— Not unfrequent in fresh water.
Skirlaugh. Nettleton. Market Weighton Canal. Pure
near Harrogate.

S. Brightwellii, Sm.—Not wnfrequent in brackish water, but

never abundant. Outlet Hornsea Meer. Hornsea

Deposit. River Hull. Ditch near Stoneferry. Reser-

voir Waterworks. Market Weighton Canal.

<

S.

Norman, on Diatomacee. — 65

S. ovata, Kiitz.— Very frequent in brackish or fresh water.
River Hull. Skirlangh. Dairycoats. Nearly pure,
North Humber Bank. Cottingham, nearly pure. Harro-
gate. Victoria Dock Timber Pond.

S. salina, Sm.—Rare. Banks of River Hull.

S. pinnata, Sm.—Not uncommon in fresh and even in
brackish water, but never abundant. Risby Pond. Cot-
tingham. MHaltenprice. Ditch near River Hull. Horn-
sea Deposit.

. angusta, Kitz.—Rare. Stoneferry Lane. Dr. Munroe.

. Crumena, Bréb.—Rare. Boggy Ditch, Saltersgate. ‘“ Birk
Craggs,” Harrogate. Ditch at Haltenprice.

. apiculata, Sm.—Rare. Boggy Ditch, Saltersgate.

. minuta, Bréb.—Rare. Thornton-le-Moor, Mr. Robt. Har-
rison. Victoria Dock Timber Pond, Dr. Munroe.

RR RR

TRYBLIONELLA, Smith.

T. gracilis, Sm.—Not uncommon in brackish water. Stone-
ferry. Humber Banks. Hornsea Deposit. Market
Weighton Canal... Very abundant and fine in a small
Ditch northward of Stoneferry.

T. marginata, Sm.—Not uncommon in brackish and fresh
water. Stallingbro’. River Hull above Stoneferry.
Outlet Hornsea Meer. Haltenprice. Market Weighton
Canal. Pond near Stepney.

T. constricta, Greg.—Rare. Ascidians.

T. punctata, Sm.—Rare in brackish water. Market Weighton
Canal. Humber Bank, in slides sent me by Professor
Arnott, collected by Dr. Redfern in 1853. Pond, Stepney,
Lane.

T. acuminata, Sm.—Not uncommon in brackish water. Rare
in fresh water. Ditches near Stallingbro’. Cottingham.
Timber Ponds, Mr. Robt. Harrison.

T. angustata, Sm.—Rare. Market Weighton Canal. Be-
verley Parks. Anlaby-Road, Dr. Munroe. Thornton-le-
Moor.

T. apiculata, Greg.—F requent in a gathering, Patrington.

T. Scutellum, Sm.—Very rare. North Humber Bank, Mr.
Robt. Harrison.

CyMATOPLEURA, Smith.

C. Solea, Sm.—Very common in fresh-water ditches. Skir-
laugh. Hornsea Deposit. Wawne. Reservoir Water-
works. Very abundant near Cottingham. Haltenprice.
Spring Ditch. Beverley Parks, &c.

66

Norman, on Diatomacee.

C. apiculata, Sm.—Rare. Cottingham. Skirlaugh. Clay

Pits, Nettleton.

C. elliptica, Sm.— Very common in fresh-water ditches.

22 2

2

N.
N.

Risby Pond. Wawne. Haltenprice. Peat Deposit,
Hornsea. Cottingham. Beverley. Market Weighton
Canal. Spring Ditch.

Nitzscuia, Hassall.

sigmoidea, Sm.—Very frequent in fresh clear water ditches.
Cottingham. Risby Pond. River Hull, Wawne. Spring
Ditch, very abundant. Harrogate. Beverley Parks.
Haltenprice.

. Brébissonii, Sm.—Local but plentiful im a small brackish

ditch near the River Hull, above Stoneferry.

. socialis, Greg. —Not uncommon ina Dredging, Flambro’

Head.

. macilenta. Greg.—Rare in a Dredging, Flambro’ Head.
. Sigma, Sm.—Very frequent in salt water pools and

ditches. Dairycoats, under Railway arch. River Hull,
frequent. Victoria Dock Piers. Grimsby. Timber
Ponds, Victoria Dock.

spectabilis, Sm.—Rare in a brackish ditch near Stone-
ferry.

eabee Sm.—Not uncommon. Haltenprice. Cottingham.
Beverley Parks.

tenuis, Sm.—Very common. Haltenprice. Beverley
Parks. Spring Ditch. Nettleton. Cottingham, very
frequent.

. spathulata, Sm.—Rare. On Breakwater Hessle, Mr.

Robt. Harrison. Sands, Hornsea. North Humber Bank,
Dr. Munroe.
angularis, Sm.—Not unfrequent in salt water. Timber
Pond, Victoria Dock. Piers, Victoria Dock. Ascidians.
lanceolata, Sm.—Occasionally from Ascidians.

N. Amphioxys, Sm.—Not unfrequent, but always much mixed.

Soil, Benningholme Carrs. Nettleton. Harrogate.
Cottingham. Wawne. Killinghall. Market Weighton
Canal.

vivax, Sm.—Copious in a brackish ditch near River Hull,
above Stoneferry.

parvula? Sm.—Not uncommon in brackish or fresh water.
Pure in a Pool at Withernsea. Victoria Dock Timber
Pond. Cottingham.

. minulissima, Sm.—In a trough for poultry.

Norman, on Diatomacee. 67

N. vitrea, Nor. M. 8.—Very local. Inasmall brackish ditch
near River Hull, above Stoneferry.

N. dubia, Sm.—Very common in brackish or fresh water.
Stallmgbro’. Cottingham, very pure. Humber Banks.
Tetney. Ditch near River Hull, above Stoneferry, abun-
dant. Wawne. Haltenprice. Dairycoats. Pure ina ditch
running from Anlaby to Hessle Road.

N. dubia Var. (3 Sm.—Not uncommon in fresh or brackish
water. Skirlaugh, nearly pure. Clay Pit, Nettleton.
Brackish ditch near River Hull. Pond in Stepney
Lane.

N. bilobata, Sm.—Not unfrequent in brackish water. Pure
under Railway arch, Dairycoats. Stalligbro’. Small
ditch near the River Hull. Outlet, Hornsea Meer.

N. cursoria=Bacillaria cursoria, Donk.—Rare. In a sand-
gathering, Hornsea.

N. plana, Sm.—Not frequent. Brackish ditch near River
Hull.

N. virgata, Roper.—Rare. Sands, Hornsea. Dredgings off
Flambro’ Head. _

N. insignis, Greg.—Rare. Dredgings off Flambro’ Head.

N. Closterium, Sm.—Not unfrequent. Salt and brackish

water. Humber Banks. Marfleet. Grimsby. Asci-
dians.

reversa, Sm.—Rare. Ascidians. Ditch near Stoneferry.

acicularis, Sm.—Not frequent. Under Railway arch at

Dairycoats. Cottingham, near Mr. Wilson’s Grounds.

Tenia, Sm.—Not uncommon. Humber Bank. Pure

near Marfleet Clough.

palea, Sm.—Not common. Cottingham. Pure near the

Waterworks, Stoneferry.

curvula, Sm.—Rare. In fresh and brackish water.
Beverley Parks. Ditch running from Stoneferry to
Sutton, Mr. Robt. Harrison.

2 2 2% 22

Ampuiprora, Ehrenberg.

A. alata, Kiitz.—Very frequent in brackish water. Humber
Banks, often pretty pure. Marsh Chapel. Breakwater,
Hessle. Ditch near River Hull, above Stoneferry.
Victoria Dock Timber Pond.

A. paludosa, Sm.—Not unfrequent in brackish water. Ditch
running from Stoneferry to Sutton. Ditch near River
Hull. Humber Banks. Ditch running from Anlaby to
Hessle Road.

A, “didyma, Sm.—Rare. Humber Banks,” Dr. Munroe.

68

py By

AS pS

22

Norman, on Diatomacee.

. vitrea, Sm.—Rare. Dredgings off Flambro’ Head.
. constricta, Khr.—Very common in brackish water. Pure

in Victoria Dock Timber Pond. Marsh Chapel. Pure
near Marfleet. Garrison Moat. Dairycoats, under
Railway arch.

. lepidoptera, Greg.—Rare. Dredgings, Flambro’ Head.

AMPHIPLEURA, Kiitzing.

. pellucida, Kiitz.—Very local. Nettleton. Very pure

near Cottingham, Mr. Robt. Harrison. In abundance
Risby Pond, near a submerged Willow Tree. Between
Spring Head and Cottmgham, Dr. Munroe. Very
copious and fine, Pond, Botanic Gardens.

. sigmoidea, Sm.—Rare. Ascidians.
. danica, Kiitz.—-Not unfrequent. Pure near Tetney Lock.

Pure, Grimsby. Humber Banks,

Navicuta, Bory.

. rhomboides Var. (3 Sm.=interrupta, Greg—Very rare. In

a ditch between Hedon and Paull, Dr. Munroe. Salt-
water ditch at Dairycoats, Mr. Robt. Harrison.
amphigomphus, Khr—Not common. Cottingham.
Wawne. Harrogate.

. lanceolata, Kiitz.—Very local. Very copious in a gather-

ing from Beverley Parks, near Woodmancy.

. Crassinervia, Bréb.—Not unfrequent in fresh water, but

always much mixed. Nettleton. Saltersgate. Cotting-
ham. River Hull.

cuspidata, Kiitz.—*requent in fresh water. Spring ditch.
Cottingham. Hornsea Meer. Hornsea Deposit. Risby
Pond. Pure in a Puddle near “ Birk Cragg,” Harrogate
Haltenprice. Stepney.

. rhynchocephala, Kitz.—Not unfrequent, but never abun-

dant. Cottingham. Risby Pond. Harrogate. Hal-
tenprice. Market Weighton Canal.

. Liber, Sm.—Rare. Dredgings off Flambro’ Head.
. firma, Kitz.

Not uncommon, but always much mixed.
Risby Pond. Cottingham. Haltenprice. Spring Ditch.

. elliptica, (WKiitz.—Very frequent, though always much

mixed. Hornsea Deposit. Springs at Haltenprice and
Newbald. River Hull. Reservoir Waterworks. Mar-
ket Weighton Canal. Cottmgham.

. ellipsis, Sm. M. S.—Plentiful im a gathermg from the

Piers, Victoria Dock.

. Smithii, Bréb.—Not unfrequent in brackish water ditches.

Ditch near River Hull. Ascidians.

Norman, on Diatomacee. 69

. Smithii, var. (3, fusca, Greg.—Ascidians.

. Smithii, var. y, nitescens, Greg.—Ascidians.

. gastroides, Greg.—Scarce. Small ditch near Stoneferry.

. minutula, Sm.—Not unfrequent in brackish water. Stone-
ferry. Ditch near River Hull. Humber Bank. Marsh
Chapel. Tetney.

. Jennerii, Sm.—Not unfrequent in salt and brackish water.

Humber, near Stallingbro’, covering the mud for miles.

River Hull, Stoneferry. Marsh Chapel. Dairycoats.

AAAS

x4

Grimsby.

N. Westii, Sm.—Rare in brackish water. River Hull.
Stallingbro’.

N. elegans, Sm. Local in brackish water. Very copious in

a stinking marsh Tetney. Small ditch near River Hull,
beyond Stoneferry.

. palpebralis, Bréb.—Rare. Mr. Robt. Harrison vide

Smith’s Synopsis. South Humber Bank, Dr. Munroe.

. Semen, Kiitz.—Local. Not unfrequent in the Hornsea

Peat Deposit. Cottingham. Risby Pond.

. affinis, Ehr.—Rare. Spring Ditch. Stream at Cottingham.

. inflata, Kiitz.— Not unfrequent in fresh-water gatherings.

Wawne. Killinghall. Market Weighton Canal. Bever-
ley Parks. Frequent in Cottingham gatherings.

N. gibberula, Kitz. Frequent in fresh and brackish water.
Risby Pond. Skirlaugh. Nettleton. Cottingham.
Hornsea Meer. Hornsea Deposit. Copious in a brackish
marsh, Tetney. Ditch near River Hull, above Stoneferry.
Wawne. Haltenprice. Spring Ditch. Market Weighton
Canal.

N. amphirhynchus, Ehr.—Not uncommon, though always
much mixed. Nettleton. Cottingham. Skirlaugh.
Harrogate. r

N. producta, Sm.—Not uncommon, though always sparse.
Boggy place, Skirlaugh. Springs near Cottingham. Hal-
tenprice. Peat Deposit, Hornsea.

N. ambigua, Ehy—Rare. Ditch near Stoneferry, leading to
Sutton. Hornsea Peat Deposit.

N. Amphisbena, Bory.—Very frequent both in fresh and
brackish water. Copious in a ditch near Stoneferry.
Nettleton. Humber Bank. Cottingham. Marsh Chapel.
Tetney. Copious near Harrogate. Ripley. Halten-
price. Market Weighton Canal.

N. spherophora, Kiitz.—Rare in fresh water. Haltenprice.
Nettleton. Hornsea Peat Deposit.

N. tumens, Sm.—Local in brackish water. Stinking marsh
at Tetney. Ditch near River Hull, above Stoneferry.

Sas Ste

70 Norman, on Diatomacee.

N. punctulata, Sm.—Rare in brackish water. Stallingbro’.
Marsh Chapel.
N. pusilla, Sm.—Not uncommon in brackish or fresh water.
Wawne. Market Weighton Canal. Small ditch near
River Hull, above Stoneferry. Cottmgham. Thornton-
le-Moor, Mr. Robt. Harrison.
N. tumida, Sm.—Rare. In a gathering from Cottingham.
N. dicephala, Kiitz.—Rare. In a ditch near the Farm House
Haltenprice. Cottingham.

cryptocephala, Kiitz.—Very abundant in almost every salt
and brackish water ditch. River Hull. Humber Banks,
pure. Victoria Dock Timber Pond. Market Weighton
Canal. Dairycoats.

N. bacillum, Ehr.—Rare in Hornsea Peat Deposit.

N. levissima, Kiitz.— Frequent in fresh-water gatherings,
though never abundant. Rocky stream, Saltersgate.
Nettleton. Cottingham frequent. Hornsea Peat Deposit.
Haltenprice. Wawne.

N. limosa, Kiitz.—Very scarce in fresh water. Spring at
Cottingham. River Hull, near Wawne.

N. Hennedyti, Sm.—Rare in Ascidians.

N. Lyra, Ehr.—Ascidians. Dredgings, Flambro’ Head.

N. Lyra, var. [3, Greg —Rare, Ascidians.

N. humerosa, Bréb. — Not unfrequent in a sand-washing,
Hornsea. Tetney.

N. Crabro, Ehr.—Rare, Ascidians.

N. didyma, Kiitz.—Not unfrequent im salt and brackish water.
Frequent in a ditch near River Hull, above Stoneferry.
Marsh Chapel a good gathering. Grimsby. Abundant-
in Ascidians.

N. binodis, Ehr.—Very rare in fresh-water gatherings. Be-
verley Parks, near Woodmancy. Market Weighton
Canal. Thornton-le-Moor.

N. Bombus, Ehy.—Rare in Ascidians.

N. Scita, Sm.—Very local in fresh-water gatherings. Springs
at Newbald. Cottingham near Springs.

N. Barclayana, Greg.—F requent in a sand-gathering, Hornsea.

N. mutica, Kiitz—Rare. Posts in salt water, Dairycoats.

N. libellus, Greg.—Rare, Aseidians.

N. retusa, Bréb.—Rare, Ascidians. Dredgings, Flambro’
Head.

N. apiculata, Bréb.—Rare. In an Ascidian gathermg.

N. bacillaris, Greg.—Local in fresh water. Cottingham.
Frequent in a spring two miles north of Cottingham.

N. follis, Ehy.—Rare. Market Weighton Canal. Beverley
Parks.

2

Druce, on Confervoidee. 71

N. forcipata, Greville—Not common in Ascidians.

N. lepida, Greg.-—Very rare in fresh water. Spring Ditch.
N. granulata, Bréb.— Rare. In a sand-gathering, Hornsea.
N. pectinalis, Sm.—Rare. Sand-washing, Hornsea.

N. estiva, Donk.—In a sand-gathering from Hornsea.

On the Reproductive Process in the CoNFERVOIDE” (with
part of Plate VI). By T. C. Drucz, Esq.

(Read January 11th, 1860.)

Tue study of the reproductive process in the Confervoideze
has occupied the attention of observers so eminent, that it
is with very great diffidence I venture to lay before you
the present imperfect observations; but two considerations,
arising one out of the other, impel me to this course. The
first, that whatever may be the real importance of the facts
I shall have the honour of submitting to you, they are at
least recorded faithfully, and have assumed a consistency and
strength I little expected at the commencement of a some-
what desultory course of study. The second is, that as the
present and coming season is favorable for the observation
of the resting spores, 1 hope to induce many more observers
to regard these organisms, humble in the scale of creation,
but full of the highest physiological interest, and possessed
moreover of beauty sufficient to reward the mere searcher
after pretty objects, for devoting to them a somewhat less
desultory attention than usual. I would commence the
remarks I have to offer to you by pointing out a few of the
difficulties with which the path is beset in this department
of research. These are of two kinds; the first, pregnant
with snares for the imexperienced observer, arises from the
tendency of the vital protoplasm to pseudo-organization ; for
it is frequently overlooked that this life-blood of the vege-
table world possesses as great a formative capacity as the
blastema of animal life; hence are presented many appear-
ances otherwise unaccountable. I have seen the contents of

72 Druce, on Confervoidee.

a ruptured cell of Vaucheria assume the form of young
encysted fronds of Pediastrum so nearly, that had I not
myself seen the process, I should have had no doubt im so
considering them ; the contents of Cladophora in like manner
bear an exact resemblance to young Palmelle. I might con-
tinue the list of these false appearances ; but, not to multiply
instances, I would just remark that in Spirogyra, the instant
a cell is injured, or the density between the contents and the
surrounding medium altered, the spires become flaccid and
exhibit a disposition to separate into globular aggregations of
chlorophylls, and around each will be found a transparent
protoplasmic layer. As this becomes inspissated, it assumes
the appearance of a true cellulose envelope, and may become
produced into stellate processes ; and thus the history of many
phenomena assumed to be connected with reproduction may
be elucidated. I have no hesitation in asserting that almost
all the obscure encysted bodies of algologists are to be
accounted for in this wise. Again, in decaying cells, it is not
unusual to find the contents resolved into a fibro-molecular
mass, exhibiting a motion very similar to the swarming in
Desmidez ; this is doubtless the ordinary molecular motion,
but it is very deceptive. -The second class of difficulties is
formidable to the physiologist and practised observer, and
consists in this (in the words of the authors of the ‘ Micro-
graphic Dictionary’), viz., the great apparent diversities that
occur in the physiological phenomena presented by what at
first appear like identical structures. I shall not touch upon
these now in detail, as we shall have to dwell upon some of
them at a later stage in our inquiry, but pass on to con-
sider, first, the premises upon which, in the reproduction of
Confervoid Algze, observers may hope to arrive at a right
conclusion. ‘To do this effectually, we must, I thmk, first
look upon the distinctive peculiarities of the class before us,
as bearing upon the phenomena we should expect to find
connected with their reproduction; and this we may do
without departing from legitimate analogy. These are the
extraordinary extent of germ capacity conferred by a single
generative act, and the continued nisus to vegetative multi-
plication rather than to generation, so long as favourable
conditions are supplied ; the independent vitality of the com-
ponent parts of even the higher families, and the complete
individuality of the phytoids of the lower; and lastly, the
great resemblance, both materially and physiologically, be-
tween the protoplasm of the Algz and the sarcode of the
lower animals. From these characteristics we may infer, first,
that in many species the true generative act would be com-

Druce, on Confervoidee. 73

paratively seldom observed; and secondly, that from the
combined conditions of the nisus towards gemmation, and
the multiform variableness of the plastic element concerned
in these changes, we should often find the true reproductive
phenomena obscured by the differing conditions and fertility
of resource exhibited by those of gemmation and vegetative
multiplication. The uniform simplicity of plan, upon which
these orders are developed, would moreover lead us to expect
a corresponding uniformity as to the organs of reproduction
throughout the group, more or less completely differentiated,
but still identical in function and purpose ; it will, therefore,
not be unscientific to consider these, first, as we find them in
the highest families of the order, with the intention of
inquiring how far it is probable that, to ‘discover the truth,
we must look for their homologues in the lower. If this
mode of investigation be legitimate, it may both lead to the
solution of the problem of the reproduction of the Con-
fervoid Algz, and, without pretending to account for multi-
farious occurrences connected with them, may enable us to
discriminate between essential and non-essential phenomena.
The Rhodosperms I pass by, as they possess an indication of
affinities higher than any of the aquatic Cryptogamia; and
would direct your attention to the Melanosperms, as repre-
sented by the genus Fucus, in which we find the provisions
for reproduction to be as follows :—First, Oosporanges ;
second, conceptacles; third, antheridia. I believe I am
justified in asserting that these several organs rather appear
to be evolved upon a higher type than those of Confervoideze
than to be so in reality. It has been ordained that the
forests of the deep should be developed upon the Crypto-
gamic type ; but it is evident that the ability of each cell to
produce zoospores, or to become a spore or antheridium,
would be here incompatible with the dimensions to which
these plants attain, and to fulfil their purposes. We there-
fore find all the fertile cells, whether gonidial, sperm, or
germ, collected together im specialized parts of the organism ;
but the specialization stops with the locality, the spores being
extruded, whether singly or in octospores, finally without a
membrane, and afterwards acquiring true cellulose envelopes,
after the manner of Confervoidese. The oosporanges are
formed merely by the breaking up of the cell-contents of a
mass of cells into zoospores, and the process is in every
respect comparable with that of the unicellular Alge ; and
although the antherozoids are developed from articulated
filaments, the antheridia are budded off from these in a
manner similar to the horns of Vaucheria. I would also

74 Druce, on Confervoidee.

mention here, as a point to remember in connection with the
process in Confervze, that the antheridial capsules, though
quickly dissolved, are detached with the contained Anthero-
zoids. I hope to be able to show that a similar process in all
essentials exists in Spirogyra, and, as seen by Pringsheim, in
CEdogonium, and by Cohn, in Spheoplea annulina. 1
have selected this genus Fucus—widely separated from my
immediate subject—because the relation of the several organs
is indubitably well known, and the fertilization by the an-
therozoids often observed. I shall now proceed to the
Siphonaceze, in which we have again the threefold type—
gemmation by zoospores, and reproduction by spores and
antheridia, as observed lately in all its details by Prings-
heim. I would here remark upon two points, viz., that the
hooklike antheridia and spores are both formed by pouchlike
protrusions from the main filament, as if for the formation
of branches; the process is therefore vegetative, until the
shutting off of the contents of the new cells by septa. I
mention this here because the outgrowth of the fructification
renders the nature of the process evident, and it does not
seem impossible that the antheridia may occasionally stop
short of perfection, and be converted into the small zoospores
of certain Confervee, and that the spores themselves, up to the
time of fertilization, or i default of it, may, by the amount
of vegetative power inherent in them, be subdivided into
zoospores, and thus account for much of the confusion at
present existing between true spores and sporangia, which
last I have little doubt true spores never become. In the
curious Hydrodictyon, the formation of resting spores has
not been discovered, but there is no doubt, from analogy, that
they exist. There is, however, one point to which I would
direct your attention, viz., the smaller zoospores or micro-
gonidia, and, so far as at present known, their ultimate fate;
these, after moving for some time, fall to the bottom, and
become encysted in little green heaps. This I believe to
occur in other of the Confervee, and to be no less than an
encysted form of the antheridial capsules; and that the
fecundation of the resting spores may take place either
before the formation of the spore coat at all, or in the spring
when it is ruptured by their expansion. I pass over the
Batrachospermee and Chezetophoraceze, in which the genera-
tive act has not yet been witnessed, with one observation,
viz., that if, as Dr. Carpenter has suggested, the setiform
terminal cells of the latter be antheridia, a connecting link
would be formed towards the lower Confervoidez, in the less
degree of differentiation between them and the hooklike

Druce, on Confervoidee. 75

antheridia of Vaucheria. It will be more consonant with
my purpose to consider the Confervaceze and Zygnemacez
together as one class, waiving any precedence in point of
classification between them in virtue of their near relation
one to the other in vital phenomena; and that this is nearer
than is generally imagined, I desire to show, by weighing
the value of conjugation (the prominent characteristic of
the latter family), as a true generative act, complete in itself.
I should have great hesitation in propounding an assertion so
heterodox, if I were not backed by the weighty authority,
Schleiden, but I truly believe that conjugation is in no case
or class essential; the obvious and rough analogy presented
by the coalescence of two cells having blinded many observers
to the evidence upon the other side.

In reference to Spirogyra, Schleiden says, “I have ob-
served the followimg cases, which prove how inessential this
process really is. Two cells were combined with the papilla
of a third cell, and thus arose four spores—one in each of the
first-named cells, and two in the third. Three cells were
combined, and the result was the formation of one spore in
the space formed by the three papille. Again, two cells were
combined; there appeared two spores, and a third spore in
the cavity of the papilla. Two cells combined together, and
here a spore was formed in each one. Another instance very
frequently occurred, in which one cell that had a papilla,
which did not combine with another, exhibited a spore formed
within the cell. Finally, it sometimes happens, although but
rarely, that a spore is formed without the cell having formed
any papilla.” This paragraph I quote entire, because it
affords, in better terms than I could have described, a com-
plete epitome of my own experience. I have only to add
that, having witnessed in many cases the endochrome in the
very act of transference, I am certain that the assertion of
Itsighsohn, that in one cell the contents are broken up into
moving spiral filaments or antherozoids, is void of foundation ;
in fact, that observer having been probably deceived by an
injured filament, the dismtegrated contents of which exhibited
molecular motion,—a source of error referred to in my intro-
ductory observations. The occurrence of non-conjugatory
species in these Conjugatez is surely sufficient evidence ; and
when, in addition to this, we find no approximation to this
process among the multitude of Confervoidez, so closely allied
in other characteristics, we may surely consider the case
proved against its essentiality.

The conjugation, so far as seen among the Diatomacee,
strengthens this view ; for here we have the spores resulting

76 Druce, on Confervoidee.

from an altered condition of two halves of a single frustule,
as in Melosira and Orthosira, and probably throughout the
filamentous group. The same process has been observed
among certain of the Naviculz, in Acnanthes, and other or-
ganisms ; and it may, I think, be safely concluded that if con-
jugation were the process which, in one shape or other, the
student had to discover as the true generative act among the
Confervoideze, its essential conditions would not vary ; and,
moreover, considering that the majority of these organisms
are admitted to be unicellular, and the conditions of a true
generative act consist in the union of two cells of different
characteristic endowments, although each cell may produce
many by internal gemmation, it is difficult to conceive that
the product of this vegetative multiplication can ever result
ina sperm and germ cell from the same parent. The theory
I would very diffidently offer to your notice is—that as a
certain definite amount of germ capacity only is conferred by
each generative act, the tendency of each growth by vegetative
multiplication is towards the degeneration of the organism.
This is evidently true and palpable to any one who has grown
Confervee in an aquarium,where the nutritive elements are
not so abundant as in their native waters. In order, there-
fore, to prolong this power of multiplication, two cells com-
bine to produce one, by the mere fusion of their respective
cell-contents ; and in cases where two spores are formed, and,
as we have seen not unfrequently in Spirogyra, after fusion
the contents part again into two reproductive bodies. I
would further venture to propose that the germ cells in these
orders are very imperfectly differentiated, and that up to the
period of fecundation there is no real difference between the
preparation of the cell-contents for zoospores and real spores ;
and that these unfecundated spores may become encysted,
aud are sporangia, while those fecundated are, in all cases, im
due time developed in the likeness of their parents. A
curious confirmation of this doctrine here occurs to me im the
only instance of conjugation, so called, among a class of
animals so high as the Articulata,—one of the Trematode
Entozoa, Diplozoon paradoxum a parasite upon the gills of
certain fishes, which in its young state, Diporpa, is destitute
of the organs of reproduction, but at a certain stage of their
existence two previously independent individuals are partially
fused into each other, and become one bi-sexual organism.
Here surely we may conclude that each of these Diporpee does
not in itself possess sufficient germ capacity to become perfect,
but that the united capacity of both affords the requisite
accumulative power ; and here there can be no question as to

Druce, on Confervoidee. 77

where the true generative act intervenes, as the phenomenon
oceurs in a class so highly organized as to afford us unmis-
takeable ova and spermatozoa in their respective organs.
Upon this plan there is nothing extraordinary in the occur-
rence of spores in each cell of a Conferva (as in Spirogyra
mirable, and Mougeotia notabilis), or in both cells of a con-
jugating filament, or in a cell to which the papilla has not
reached that of the one opposite. And indeed, finally, I
would say that there is not anything remarkable in any
spherical aggregations of endochrome within cells, for their
appearance is often the precursor of decay in injured fila-
ments. So far we have had to deal with facts well ascertained,
however open they may be to difference of interpretation. I
have now to present to you occurrences resting principally
upon my unsupported observations. These, however, have
assumed a consistency which, when coupled with my previous
conviction that conjugation is not the true reproduction in
Confervie, have made me deem these observations of sufficient
importance to submit to your consideration. The late Pro-
fessor Henfrey mentions, in the ‘ Micrographic Dictionary,’
as an abnormal occurrence in Spirogyra, the conversion of the
endochrome in certain cells into large colourless zoospores ;
this it has been my good fortune to witness in so many in-
stances, that it is impossible to regard it otherwise than as
connected with reproduction. It has also presented itself in
Cidogonium, and the process is as follows, in both cases.
The Chlorophyll vanishes by degrees from the cells, which
become at last diaphanous ; though obviously still full of cell-
contents, the characteristic nucleus of Spirogyra is enlarged,
and the protoplasmic threads thickened and connected with
nucleus-like aggregations of protoplasm at the sides; nuclei
and protoplasmic threads not so definitely arranged, but
still obvious, are to be seen in (idogonium, and the contents
at last break up into the large colourless zoospores above
mentioned ; these grow in size, become spherical, and are
gradually filled with a purplish black endochrome, which at
last becomes dense, though evidently granular; and finally
the capsules burst and discharge minute bodies, moving
actively, into the cavity of the cell; although my power of
350 diameters was insufficient to detect any cilia. They most
resemble the spermatia of lichens. This I believe to be the
antheridial function in Spirogyra, and so far in all essentials it
agrees with the account of Pringsheim on (E£dogonium,
excepting that the antheridial capsules discharge their con-
tents before leaving the parent cell ; but the foregoing process,

I have said, obtains also in (idogonium, and is at first sight

78 Druce, on Confervoidee.

difficult to reconcile with it. Recollecting, however, that in
(Edogonium the ordinary zoospore is formed from the whole
euntents of the cell, we may conceive each characium to be
the primordial utricle, full of antheridial capsules, which
burst within it, freeing the antherozoids into its cavity before
the dehiscence of the lid. This process I have also been so
fortunate as to witness; the characium being full of globular
bodies, and presenting a totally different appearance to that
of the same phytoid at a later stage, when the antherozoids
are swarming up to the lid, after the manner of the Des-
mide ; the only difference being, that this aggregation of the
antheridial capsules is discharged from the parent cell at an
earlier period, and provided with sufficient vegetative life to
enable it to elaborate the antheridia independently.

It further appears to me, that the generative act im Con-
fervee may, and probably does, take place at all periods of the
year ; that spores, formed by conjugation and otherwise in the
spring, are fecundated at once by the antherozoids after the
manner I have named; whilst in the summer, in Cidogonia
the vegetative process is too active to wait for the develop-
ment of the antheridia within the parent cell; the cycle of
their life hurries on, and the whole aggregation of antheri-
dial capsules is emitted as a zoospore. The resting spores
only attract attention in the autumn, because their appearance
is more distinctive, and they are provided with additional
envelopes to enable them to withstand the rigour of winter.
Other occurrences there are more difficult to account for, but
the supposition that the antheridial capsules may become
encysted for the winter, like the resting spores, will go far to
explain it, if it may only be received. I have noticed a
swarming of minute gonidia in quite young cells of CGidogo-
nium, radient with Chlorophylls, these atoms crowded to one
end of each cell as if to escape; but of this there was no
probability ; and perhaps, although I do not speak this upon
the authority of further observations, these represented the
microgonidia of Hydrodictyon, but became encysted within
the parent cells. Pringsheim has noticed that encysted
bodies in Spirogyra produced small zoospores. Now I have
no doubt that here the encysted bodies are the large colour-
less zoospores; the development of the antherozoids being
arrested by the approach of winter. In Spheroplea annulina,
in which the only difference seems to be that the primordial
utricle forms one antheridial capsule, instead of subdividing
into many, Cohn has witnessed the fertilization of the spores
by the antherozoids resembling exactly those I have seen in
Spirogyra and (Edogonium. In Chlorosphera, Professor

Druce, on Confervoidee. 79

Henfrey has described antheridia of somewhat higher grade,
having definite tubular apertures, and discharging similar
corpuscules, occurring simultaneously with the resting spores;
so that hardly any doubt can remain here as to their co-
relationship. I should here mention, that Professor Henfrey
suggests an affinity with the colourless zoospores witnessed by
him in Spirogyra. I beg therefore to disclaim any appro-
priation of discovery in these observations, only believing I
have been so fortunate as to continue them one step further.
I have seen a similar process in Cladophora, and in a small
branched Conferva allied to it: the capsules were adherent
after the manner of those of Gidogonium, excepting that
they were affixed by a point incised, instead of rootlike pro-
cesses; but the contents were freed by the dehiscence of a
definite lid, and corresponded in all other respects entirely.

In Closterium moniliferum I have found the chlorophyll
to disappear, as in Spirogyra, and the spheroidal bodies
rolling to and fro in the frustule, filling by degrees with the
purplish-black cell-contents, and finally bursting imto an-
therozoids.

In the last number of the ‘Microscopical Journal,’ Mr.
Archer has described and figured bodies apparently similar
to those I have mentioned, in an abnormal Tetmemorus, but
also affirms it to be a frequent occurrence in Tetmemorus,
Micrasterias, and Euastrum, and he has also seen a similar
phenomenon to that which Professor Henfrey describes in
Chlorosphzera, mm Clostertum, viz., the formation of fiask-
shaped bodies, discharging antherozoids, which in both cases
are, I would suggest, the encysted antheridia. Cohn’s
account of the formation of the antheridia and antherozoids
in Volvox, agrees also in all main poimts with my account in
Spirogyra and Cedogonium. In CXdogonium I have had the
good fortune to witness, I believe, the actual fecundation, a
drawing of which I have attempted, which has at least the
merit of having been drawn from life.

These are my facts; and, if the mterpretation I have
placed upon them be correct, they serve to show that, in the
several classes named, the fructification attains essentially to
the same degree of organization as that of the higher Alge ;
and as approximate occurrences have been from time to time
observed in almost all of the Confervoid Algze, the type may
fairly be considered universal to the group. The summary
of the foregoing is—first, that conjugation is not the genera-
tive act in organisms in which it occurs, and not essential,
though it may be subservient to the preparation of true
spores for fecundation, Secondly, that true fecundated spores

VOL. VIII.

80 Druce, on Confervoidee.

are never sporangia, although those unimpregnated may
remain in the condition of encysted gonidia, or, under
favorable circumstances, subdivide at once into zoospores.
Thirdly, that the true spores are fecundated by antherozoids —
developed in capsules, at first themselves motile, and after-
wards either inside the parent cell, as in Spirogyra, or outside,
as generally in Gidogonium, freeing their contents either by
the rupture of the cell-wall or the dehiscence of a definite
lid. Fourthly, that the antheridia may become encysted
in the autumn, as well as the resting spores, and impregna-
tion take place either before the formation of the envelopes
of the spore in the autumn, or in the spring, when these are
ruptured. (See Plate VI.)

In conclusion, I am conscious how little I have performed
towards the fulfilment of my programme at the outset, and
‘how easily I may be condemned upon my own premises; but
I proposed it to myself rather as an indication towards nght
investigation, than with any hope of completing it myself on
the present occasion. Finally, I lay claim to very little novelty
in the foregoing observations, my object having been rather
the attempt to consolidate and connect together facts already
known, than to proclaim a new thing; and I do desire to call
the attention of microscopists who have no special study, to
these lowly organisms, not merely that it is a favorable
field for research, offermg the charm of novelty and ever-
_ changing beauty, but also because the study is full of the
highest physiological interest; for from unicellular organisms
is there the greatest chance of discovering the great funda-
mental, and as yet hidden, laws of life.

81

MICROSCOPICAL SOCIETY.

ANNUAL MEETING

February 8th, 1860.

Dr. LanxesteR, President, in the Chair.

Report of Councit.

“Tw accordance with annual custom, the Council have to
make the following report:

The number of members reported’

at the last anniversary was . . . 276
There have been since elected . 28
Making atotal of . 304.
This number has to be reduced by—
Deceased . . - 7
weumdfawn . . . . .. . 1W=19
Leaving a final total of . . . 285 as the present

number of members of the Society.

“The Library has been increased by about 160 works,
including serials—chiefly presents ; 77 of them consist of cata-
logues of objects of natural history, presented by the Trustees
of the British Museum ; 14 others have been purchased with
a fund arising out of the sale, to members, of the early ‘ Trans-
actions,’ at a reduced price, which fund it is intended shall
be applied solely to the supplying the Library with such
works as it may be thought desirable to add to it. There
still remains a considerable surplus available for this pur-
pose.

“The collection of objects also has received many additions.

“The arrangements for the distribution of the ‘Journal’
continue the same as last year.”

my.

Auditors’ Report.

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83

Revort of the Liprary Committers of the Microscopican
Sociery.

“Since the last Report, some valuable additions have been
made to the Library, comprising sixteen volumes, and 143
pamphlets presented, and sixteen volumes purchased, or
exchanged for old numbers of the ‘Transactions’ or
‘Journal.’ The whole of the books m the Library have been
examined ; fifty-six volumes have been bound ; the collection
of pamphlets has been classified, and bound in five volumes ;
and a catalogue of the whole has been prepared, printed, and
presented with the ‘ Journal’ to the members.

“The Committee draw especial attention to the presenta-
tion by W. S. Sullivant, of the United States, of seven works
on Mosses, &c.; and to seventy-seven numbers of the British
Museum publications, by the Trustees.

“The Committee trust that arrangements will be made at
an early period to provide accommodation for the books in
the rooms they at present occupy, so as to be more available
to the members. k

“Tn conclusion, they strongly recommend that the follow-
ing works should be added to the Library as soon as possible:
‘Der Organismus der Infusionsthiere,’ by Dr. F. Stein;
“Die Kieselschaligen Bacillarien,’ by F.'T. Kiitzing ; ‘ Mikro-
geologie, by Dr. C. G. Ehrenberg.

“F.C. S. Roper.
Gero. E. BLenxins.
J. H. Rozerts.

R. J. Farrants.”

The President delivered the following address :

The Presipent’s Apprzss for 1860.
By Dr. Lanxester.

GENTLEMEN,—It gives me great pleasure to address you at
the close of my term of presidency, after you have heard
the Reports of your Council and Treasurer, and which repre-
sent our Society ina condition which commands our mutual
congratulations. At the present we have a larger number of
members than at any previous time in the history of our
Society. However much we may regret the withdrawal of

84 The President’s Address.

some of our members, the addition to our numbers more
than compensates for the loss. It is, however, always a
painful task on these occasions to have to reflect that our
numbers are diminished by the hand of death. During the
past year seven of our members have been thus removed, and
amongst them you will recognise some of the earliest and
most active members of our Society. They are Mr. J. N.
Furze, Professor Henfrey, Mr. Andrew Ross, Mr. E. Speer,
Mr. W. Stuart, Mr. Richard Taylor, and Dr. H. Rees.

Some of these gentlemen demand from me more than a
passing notice; and I would first refer to Professor Henfrey,
whose death at an early age we have not only to deplore as a
loss to ourselves, but to science generally. Although, from
disease of the lungs contracted in youth, he was never
robust, he yet by unceasing industry acquired for himself a
European reputation. He was originally intended for the
medical profession, and studied at Bartholomew’s Hospital;
but the state of his health mduced him to abandon the
arduous duties of practice, and devote himself entirely to
science. The branch of study to which his tastes led him
was that of botany, and in this science more particularly he
attained his great distinction. One of his earliest works was
on ‘ Anatomical Manipulation,’ which he wrote in con-
junction with Mr. Alfred Tulke; this was published in 1844.
About this time he was appointed Botanist to the Geological
Survey of the United Kingdom; he held this post but for a
short time. He was subsequently appointed lecturer on
Botany at the Middlesex Hospital, and at the St. George’s
Hospital School of Medicine. In 1847 he published his
‘Outlines of Structural and Physiological Botany ;’ this
work was illustrated by plates executed by himself. Several
of these plates were devoted to the illustration of the micro-
scopic structure of plants, and were faithful representations
of his own observations. He had at this time carefully
investigated the views of Schleiden and Hugo yon Mohl
on the cytoblast and primordial utricle, and his work, at the
time it was published, was a faithful epitome of the various
observations that had been made on the histology and
development of vegetable tissues. This work laid the founda-
tions of one much more extended and complete, which he
afterwards published in 1857, with the title, ‘An Elemen-
tary Course of Botany, Structural, Physiological, and
Systematic; with a brief outline of the Geographical and
Geological Distribution of Plants.’ This work, which gives
the most complete view of the histology and development of
plants in our language, contains a large amount of original

ee eae ——

The President’s Address. 85

matter on the development of the cells of plants, and the
phenomena of reproduction, more especially amongst the
lowest forms of plants. Between the publication of these
two works, he devoted the larger portion of his time to
microscopic observations, and he published several papers on
these subjects in the ‘ Transactions of the Linnean Society,’
the ‘Annals and Magazine of Natural History,’ and in the
Reports of the British Association. The subject to which he
gave the largest share of his attention was the nature of the
changes which go on during the process of the impregnation
of the ovulein the Phanerogamia. Schleiden had opposed the
view of Amici, that the embryo is developed from an “ em-
bryonic vesicle’ contained within the “sac of the embryo,”
and maintained that it was formed within the pollen-tube.
Henfrey, from an early period, maintained the correctness of
the first view of Amici, and made a great number of obser-
vations on the subject. The whole of that part of Professor
Henfrey’s work devoted to the histology and reproduction of
plants is well deserving the study of “those engaged in the
microscopic inv estization of the structure and formation of
plants. Mr. Henfrey contributed two papers to the Transac-
tions of our Society—one in the fourth volumeyf the new
series, “On some Fresh-water Confervoid Algz new to Great
Britain;” and one in the seventh volume, “ On Chlorosphera,
a new genus of Unicellular Fresh-water Alge.” It was in
such papers as these that he displayed his careful habits of
observation with the microscope ; and had his life been spared,
we might have expected from him large contributions to our
present knowledge of microscopic organisms. During the
last five years of his life he was occupied, in conjunction with
Dr. Griffiths, in the laborious task of compiling and editing
the ‘Microgr aphic Dictionary.’ Mr. Henfrey undertook the
whole of that part of the work which related to the micro-
scopic structure of plants. The value attached to this great
work was indicated by the speedy demand for a new edition,
which was completed just previous to the death of Mr.
Henfrey. We have here treasured up all that had been done
_for the advance of botanical science by the aid of the micro-
scope; and our friend could hardly have left behind him a
more fitting monument of his industry and appreciation of
microscopic inquiry, than his own contributious to this com-
prehensive volume.

But besides these labours having more especial reference
to our specialty, Mr. Henfrey produced many other valuable
works. In 1852, he wrote a volume on ‘The Vegetation of
Europe, being an account of the distribution of the princi-

86 The President’s Address.

pal forms of plants found in Europe. The geography of plants
found in him an able exponent, and he constructed the maps —
and wrote the letterpress on the distribution of plants, in |
‘ Johnston’s Physical Atlas.’ He also further contributed —
to make this subject popularly understood, by translating
from the German, Professor Schouw’s ‘ Earth, Plants, and
Man.’ His acquaintance with German botanical literature
was extensive, and he translated into English Schleiden’s
‘Lectures on the Biography of Plants,’ and Alexander
Braun’s ‘ Rejuvenescence in Nature,’ a somewhat specula-
tive but interesting volume, published by the Ray Society.

Although he had not the gift of free speech, his earnest
desire to impart all he knew, rendered him a popular teacher
in his class; and when the late Professor Edward Forbes
resigned his chair at King’s College, he was appointed Pro-
fessor of Botany in his place. Besides bemg a member of
our own Society, he was a Fellow of the Royal and Linnean
Societies, and had the appointment of Examiner in Natural
Science at the Royal Military Academy at Woolwich, and at
the Society of Arts. He was of a retiring and amiable
disposition, and sincerely beloved by all those who knew him
in privateslife. He fought a brave fight, and is a bright
example of what a firm will can do amidst the feebleness of —
habitual indisposition.

In Mr. Andrew Ross the Society has lost one of its original
members, and one who has had no little share in brmging
the microscope to its present perfect state. He was an
optician by profession, and laboured with Pritchard, Goring,
Holland, and others, to bring the simple microscope to per-
fection, before Mr. Lister had made his great discovery of a
combination of achromatic glasses in a compound arrange-
ment. Mr. Ross was one of the earliest makers who com-
prehended Mr. Lister’s principles, and carried them imto
practice in the manufacture of compound achromatic imstru-
ments. The perfect success, however, of these glasses was
attended with a defect which in some measure was a draw-
back to their usefulness. This arose from their use in the
examination of objects covered with thin plates of tale or
glass, as the corrections for uncovered objects were found erro-
neous for those which were covered. Mr. Ross discovered the
means of correcting this defect, which consisted in separating
the anterior lens of the combination from the other two, in
such a way that it could be brought further or nearer to
them, according to the necessity of the case. An account of
this discovery and its application will be found in the fifty-
first volume of the ‘Transaction of the Society of Arts,’ pub-

The President’s Address. 87

lished in 1837. This method of correcting for covered and
uncovered objects is applied to all our better object-glasses,
and has since received some improvements at the suggestion
of Mr. Powell. Mr. Ross has also from time to time added
improvements to the general structure of the compound
microscope, and suggested a variety of modifications in its
accessory apparatus. If we are more indebted to him for
his practical talent as a mechanician, it was not because he
had not the ability to contribute to the literature of his pro-
fession. We have, in fact, from his pen one of the best
articles that ever appeared on the microscope. This article
was contributed to the ‘ Penny Cyclopzedia,’ in 1839, and is
more or less the foundation of most practical treatises written
since that time. Besides this masterly article, and the paper
already referred to, I am not aware that Mr. Ross has con-
tributed anything to the literature of the microscope; but
these must ever give him a place amongst those who asso-
ciated with Joseph Jackson Lister, and assisted to make the
compound achromatic microscope the great imstrument of
research it is at the present day.

Those who have been in the habit of attending the scientific
societies of the metropolis during the last twenty years will
all recollect the intelligent and benignant face of the late
Mr. Richard Taylor. Although for the last few years he had
withdrawn from the activity of London life, his decease
did not take place till the begining of last year, and he con-
tinued a member with us till his end. Mr. Taylor was not so
well known as aman of science, as he was as a man of letters
who sympathised with men of science. He was a scholar,
and cultivated that class of literature which led him to regard
with especial imterest the progress of natural science. He
was especially associated with those who cultivated natural
history, and was for many years a joint editor, as well as
printer and publisher of the ‘Annals and Magazine of Natural
History. He also edited four volumes of Scientific Memoirs,
which were published by him from 1838 to 1846, containing
translations of valuable scientific papers from the French and
German. He was also, in conjunction with the late Mr.
Richard Phillips, the editor of the ‘ Philosophical Maga-
zine,’ from 1827 to 1832. These varied labours in connection
with the literature of science, constitute for him a strong
claim to our remembrance and gratitude. His connection
with the Linnean Society was more close than with any
other, and he acted for many years as the Assistant Secretary
of that Society.

The death of Mr. Furze is one that must have caused great

88 The President’s Address.

pain and surprise to many of the members. He was a man
in the prime of life, and carrying on a large and successful
business; but in the midst of all he found time to cultivate
a taste for microscopic research. Without contributing to
our Transactions, he took a great interest in our proceedings;
and the intelligence and energy with which he cultivated the
microscope, as an instrument of research, must have done
much to recommend its use amongst a large circle of his friends
and acquaintance. I accidentally had a proof of this some
years ago, when visiting a village by the sea-side, in the
county of Suffolk, where I found Mr. Furze had been staying
for a few weeks before I had arrived. I had not long been
there before I heard of the impression he had produced on the
minds of the villagers by his daily demonstrations, upon
the sea-shore, of the microscopic structure of the creatures
with which the coast abounded. I have often thought that
this would form the subject for a picture to a painter
of the nineteenth century—a naturalist exhibiting the
wonders of animal structure through a microscope to a rural
population. By such pictures the great history of our civili-
zation might be told. :

Mr. E. Speer, though not a contributor to our Transactions,
was deeply impressed with the value of the microscope as an
instrument of research; and, in the hope of alleviating human
distress by its agency, presented, before his death, a magnifi-
cent instrument, made by James Smith, to the Hospital for
Consumption and Diseases of the Chest.

I would now call your attention to the state of our library.
Since I addressed you last year, several works have been
purchased, and others have been presented; so that we have
altogether 186 complete volumes, with about 140 pamphlets
and papers of various kinds. Although the number of books
is not large, they present a tolerably complete epitome of the
literature of the microscope in our own language. A cata-
logue of those works has been prepared by the Library Com-
mittee, and was published in the Transactions for the past
year ; separate copies have also been printed for the use of
the members. <A glance at this catalogue reveals to us the
curious fact that the literature of the microscope has had two
distinct periods; the first period may be said to commence
with the establishment of the Royal Society, in 1660. From
this time to the latter end of the eighteenth century, the
‘Philosophical Transactions’ abound with papers and memoirs
devoted to the structure of the microscope and observations
by its aid; and it is on this account that I think it would
be most desirable that the members of this Society

The President’s Address. 89

should have the opportunity of consulting these precious
volumes in our own library. The works that were the
result of this activity are, I believe, tolerably completely
represented in our catalogue. The first to which I would
call your attention is the ‘ Micrographia’ of Robert Hooke,
published in 1665, and which, considering that it was the
first work devoted to the literature of the microscope,
is a perfect marvel. Its illustrations and the sound obser-
vations of the author may be studied with advantage at
the present day. This was followed by the works of Grew
and Malpighi on the Anatomy of Plants. Although Malpighi
was a foreigner, his works were published by the Royal
Society of London ; they consisted mostly of papers which
had appeared in the ‘ Philosophical Transactions.’ He was
the first to observe the passage of the blood through the
capillary vessels, and his works otherwise abound with sound
observations. In 1675 the communications of another dis-
tinguished foreigner commenced in the ‘Philosophical Trans-
actions;’ and we may claim Leeuwenhoek almost as an English
writer. His collected works will be found in our library, and
contain an astonishing variety of observations on animal and
vegetable structure. During this century Swammerdam wrote
his treatises on insects, and made many curious observations
with the microscope on the generation of the frog and other
animals.

These researches bring us over the seventeenth, and carry
us on to the commencement of the eighteenth century. Here
we meet with the investigations of Trembley, on the Hydra;
of Lyonet, on the Caterpillar of the Goat-moth ; and of Spal-
lanzani, on a variety of subjects. The latter was the first to
maintain the independent animal nature of the Infusoria, and
contributed a large number of observations on the function
of animal impregnation. The works of Baker and the two
Adamses close the labours, as far as our library will indicate
them, of the eighteenth century, on microscopic subjects.

If we now turn over the pages of our catalogue, we in vain
look for the continued activity of the preceding period. Ob-
servers seemed to think the microscope had done all for
science that could be accomplished by its aid. It is true, the
instrument was not forgotten. There were those who believed,
if its powers could be increased, much more might be done by
its aid. Brewster, Pritchard, Goring, Tulley, and others,
worked at the construction of lenses, in the faith that more
might be accomplished by its aid than had hitherto been
supposed. Here and there observers were working unnoticed.
Robert Brown was laying the foundation of the science of

90 The President’s Address.

Histology and the laws of development in relation to the vege-
table kingdom, and Ehrenberg was studying the forms of
infusorial animalcules in every part of the world. It was not,
however, till the production of Mr. Lister’s paper m the
‘ Philosophical Transactions, in 1828, that a new impetus
was given to microscopical research, and a literature sprung
up unrivalled in the past history of the microscope. It would
be impossible for me here to attempt to analyse this literature.
It includes investigations with the microscope in every branch
of natural science. It contains observations on the forms of
crystals, plants, and animals; it embraces the highest gene-
ralisations of physiological science, and includes countless in-
vestigations into the origin, forms, and modes of growth of
organs and the ultimate parts of organs of both plants and
animals. Altogether, it forms an assemblage of facts and
reasonings the most imposing that has ever been presented
to the human mind in the same space of time in the whole
history of science. To increase the stock of this literature, to
render it accessible to all inquirers, and to make it the means
of educating future observers by the aid of this mstrument,
will, I hope, be one of the constant aims of this Society.
From the Library let us turn to the Museum. It seems to
me, when we consider the little cost and facility of keeping
microscopic objects, that the development of the Museum
should be more an object of attention than it has ever yet
been to the Society. The whole collection of objects amounts
to six hundred and sixty-three, seventy-three of which have
been added during the past year. If illustrated works are a
source of instruction, and important as enabling one inquirer
to understand the views of another, there can be no doubt that
properly named specimens are of more importance. This is
especially the case with the forms of mimute animals and plants
which are described from time to time by different authors. If
collections of species named by authors could be obtained from
those who have first described them, they would be of great
value for reference im all time to come. When we consider

that the number of specimens in our Museum is not so great

as those offered in the lists of those who vend these objects, and
that their maximum value is not twelve pounds, I would sug-
gest that we should do one of two things—either abandon
the idea of a collection altogether, or place it im a position
more worthy the credit and dignity of the Society.

Let me now call your attention to the work of the Society
during the past year. Having been hastily summoned to
quit our apartments in Regent-street, at the beginning of the
year, aud not having a place to meet in at the commence-

The President’s Address. 9]

ment of the session, the council have found it convenient to
curtail the number of our meetings; so that durmg the past
year we have held but seven meetings, including the soirée at
the South Kensington Museum, and the annual meeting on
the 16th of February. Perbaps I may be allowed to say a
word or two, first, with regard to the soirée. From the cir-
cumstance of the council having determined to hold this an-
nual gathering in the extensive rooms of the Museum at
South Kensington, which were placed at their disposal by the
Committee of Council on Education, it was one of the
largest meetings of the kind that had ever been seen in the
metropolis. About three thousand persons were present, and
the display of microscopes, and their accessory apparatus, was
such as had never been got together before. Upwards of
three hundred microscopes, exhibiting all the forms and ap-
plications of the instrument, were displayed. Although this
exhibition of the instrument, and the assemblage of so large a
number of patrons, might, consistently with the objects of
your Society, have been purchased by a considerable outlay of
funds, it must be gratifying to you to hear that, by the judi-
cious arrangements of your council and the liberality of indi-
vidual members, this immense meeting has not only not
entailed on your funds any loss, but that you have been
gainers by it to a slight amount.

As the ordinary meeting-nights of the past year have been
only six, including the first meeting of this year, you will not
be surprised to learn that only ten papers have been read.

The first paper was by Dr. Bowerbank, ‘On the Organiza-
tion of Grantia ciliata,’ and contained a more detailed ac-
count of the structure of this curious member of the sponge
family than had hitherto been published. To Dr. Bowerbank
belongs the credit of having studied this interesting family of
organized beings in the most exhaustive manner; and it will
be gratifying to all present to know that he is now preparing
a complete monograph of the British forms of sponges, which
will be published by the Ray Society for the year 1861.

Our next paper was one “ On Diatomacez collected in the
United States,” by Arthur M. Edwards, Esq. Besides this
paper from the other side of the Atlantic, we have had an-
other read, “ On Diatomacez found near Gambia, Ohio,” by
Professor Hamilton L. Smith. These papers are interesting,
as giving an account of the distribution of the Diatomacez in
the New World, and they have been received by our Society
as a gratifying proof that our aims and objects are recipro-
cated and understood by scientific inquirers in America. Dr.

92 The President’s Address.

Greville, of Edinburgh, has communicated a paper describing
several new forms of the beautiful Diatomaceous genus Campy-
lodiscus. Mr. Roper, in a paper on Triceratium arcticum,
has shown that this genus must no longer be regarded as a —
non-catenated form of Diatomacez, as in its natural state its
triangular frustules are connected together as in many other
forms of this family. The last contribution on Diatomacez
is by Dr. Wallich, who, in his paper “‘ On the Siliceous Orga-
nisms found in the Digestive Cavity of Salpz, and their rela-
tion to the Flint Nodules of the Chalk Formation,” has
endeavoured to account for the presence of forms of Diato-
maceze and Desmidez in the flints and siliceous nodules of
the chalk, by their having been collected by Salpz in their
stomachs, then swallowed by whales or other large animals,
and, on the death of these creatures, been deposited in the
bed of the ocean, in the concretionary form in which they
are now found.

We may learn from these papers how great an interest
attaches to the study of the Diatomacez, and how some of
the highest problems in the history of the life upon our globe
may be solved by their study. Formed of imperishable
material, and, once formed, not experiencing the decay which
is the law of every other existing organism, these minute ~
beings leave behind them the most extensive record of their
existence. Not only can we examine their forms, many of
which are exquisite from their graceful outline and delicate
carving, but even with regard to extinct species, we may
gather the history of their habits and mode of increase, and
other points, from the localities in which they are found.
Independent, however, of the interest which attaches to the
study of the Diatomacez as a group of organized beings pre-
senting us, as it were, with the first struggles of life against
the physical and chemical forces of brute matter, they are
capital objects with which to train the eye and mind to habits
of correct observation. It is in this group of beings that the
advanced microscopist secks for the severest tests with which
to try the highest powers of his object-glasses; and it is in
the observation of the forms and markings of these the most
delicate productions of the Creative Hand that the young
microscopist will best acquire the habit of distinguishing
minute differences and resemblances.

An interesting communication was read at our June
mecting, from Mr. George F. Pollock, containing “ Obser-
vations on Granulated Blood Discs.” This paper indicates
that, however well the blood. dises may have been observed,

The President’s Address. 98

they still present phenomena whose full significance is not
yet understood, and await for their explanation further
observation and reflection.

The last paper read at our meetings, and not yet published
in our Transactions, was one by Mr. Druce, “ On the Repro-
ductive Process in the Confervoidez.” In this paper Mr.
Druce shows that there is yet much more to be done in making
out the true reproductive process in Confervoidee. He
agrees with previous authors in the conviction that the
process of conjugation in this family is not necessarily indi-
cative of a union of germ-cells and sperm-cells ; and certainly
in most cases of conjugation this fact has not been made out.
It is not at all inconsistent with our present knowledge of the
ordinary function of vegetative reproduction by the multipli-
cation of similar cells, which I have elsewhere ventured to
call “homogenesis,’* that it should assume the forms and
external phenomena of true generation (heterogenesis). We
see this occurring im the fact that seeds which have originated
quite independent of the influence of the sperm-cell occur in
many of the higher forms of plants, and that ova and vivi-
parous spores, as in the case of the bees and aphides, are
produced under the same circumstances. It is, then, an in-
teresting field for the microscopist, to study those lower
forms of vegetable life in order to ascertain what phenomena
are connected with the vegetative cell multiplication or
homogenetic development, and what are the forms in which
the phenomena of heterogenesis are presented to us.

These are the principal subjects which have been presented
for microscopic inquiry during the year. In addition to
these papers, we have had two on improvements in the struc-
ture of the microscope. One of these was by Mr. Richard
Beck, “On the Universal Screw.” Although Mr. Beck’s
paper pointed out some defects in the working of the plan
for obtaining a universal screw, by which the object-glasses of
different makers might be used by the same body, as carried
out by a committee of our Society, it is very gratifying for
us to know that, generally speaking, our plan has been most
successful, and that microscopists, both in this country and
America, recognise the suggestions of the Society as a great
boon. The other paper on the instrument was by Mr. James
Smith, who, in his description of a section and mounting
instrument, with other contributions which he has made to
_ the Society, has displayed considerable skill in the invention

* Preface to translation of Kiichenmeister on ‘Animal and Vegetable
Parasites.’

94. The President’s Address.

of apparatus for microscopic investigation ; and should he

continue to apply himself to this department of study, there
can be no doubt that the microscopic inquirer will be
indebted to him for further improvements in the mechanical
arrangements of the microscope.

But the labours of our Society do not end here. You must
not forget that the ‘ Journal’ originated in your Society, and
has been conducted under its auspices, and that the papers
published in its pages are as much a part of your organization
as the papers published in your ‘Transactions. For the
very reason that the papers in your ‘ Transactions’ have been
less in number, those in the ‘ Journal’ have been more, and

in no year since its origin has the ‘ Journal’ been more rich

in original papers than during the past year. These papers
have been eighteen in number, besides translations and a
variety of communications in the form of notes and memo-
randa. No less than ten of these have been on the Diato-
mace; and although some may regard this as a dispropor-
tionate space for one set of objects to occupy, it must be

remembered that these organisms are exclusively muicroscopi- —

cal, and that at the present moment they possess for the
microscopist a high interest, for reasons which I have before
stated.

Two of the remaining papers, by Mr. Rainey, deserve your
especial attention ; one ‘‘ On Dental Tissue,” the other “ On
the Starch Granule.’ The object of Mr. Ramey in these
papers is to show that the formation of the dental tissues, as
well as of the starch granule, are due to the same process as
that which he has so ably shown to take place in the produe-
tion of shell and other hard parts, in his work on ‘The Mode
of Formation of Shells of Animals,’ &c. As long ago as 1840
and 1841, Harting and Link published separate treatises*
on the Production of Membranes, as the result of a process of

crystallization of inorganic substances in contact with organic —

matters ; and from time to time the -presence of the aggre-
gating force of crystallization has been alluded to, as possibly
modifying the results of that action which has been called
cell-force. It is, however, to Mr. Rainey that we are indebted
for a full investigation of this subject ; and he has shown that —
in all cases where a considerable quantity of inorganic matter
is present, as in the case of carbonate of lime in shells, and
phosphate of lime in bones and teeth, that the peculiar form
of the tissue is due to the properties of the i inorganic matter

present. In his paper “ On the Starch Granule,” he has car-

* See Report on Botany, of Ray Society, 1845, pp. 6, 7

1
|
|
7

The President’s Address. 95

ried this view further, and endeavoured to show that the pe-
euliar form and structure of grains of starch are due to
minute quantities of morganic matter. For this process he
has adopted the term “ molecular coalescence.” These ob-
servations are interesting in connection with the views of
those who are opposed to the cell-theory of Schleiden and
Schwann, and who prefer to speak of the whole of the phe-
nomena of the formation of the tissues of plants and animals
as a process of “ differentiation.”” In connection with this
subject, a paper by Professor Williamson, in the last October
number of the ‘ Journal,’ ‘On some Histological Features of
the Shells of Crustacea, is well deserving attention. He
there shows that certain tissues in the shells of the Crustacea
that had been regarded as cellular in their structure, are pro-
duced in a protoplasmic matter, independent of cells or nuclei.
I will not, however, enter here further into the matter, but
call your attention to this subject as a field inviting further
inquiry, and likely to yield abundant fruits to those who have
leisure and opportunity for its culture.

To Mr. Currey the pages of our ‘ Journal’ are largely in-
debted for his varied contributions in the field of mycology.
His ‘ Mycological Notes,’ in the number of the ‘ Journal’ for
July, is an example of how various observations on the same
series of objects may be communicated with great advan-
tage to those who are working in the same direction. In
these busy days, when so many observers are investigating the
same subjects, it becomes a matter of importance to all to
know what others are doing, so that no time may be wasted
in re-discovering what others have done. In connection with
the subject of mycology, I may also draw attention to a
translation in the last number of the ‘ Journal,’ in which M.
De Bary attempts to show that a certain group of the Fungi
are rather of an animal than of a vegetable nature. Although
considerable doubts may be thrown on M. De Bary’s conclu-
sions, his observations indicate the interest that still attaches
to the question of the limits between the animal and the
vegetable kingdoms. It is only by the aid of the microscope,
used by well-trained observers, that such a question can be
decided ; and large groups of forms belonging to the Proto-
phyta and Protozoa present themselves for investigation on
this subject. Here, too, is a district in which perhaps the
inquiries of the microscopist may come in to assist the in-
quiry which has just been opened by one of our most dis-
tinguished naturalists as to the origin of species.* It is only

* On the ‘Origin of Species,’ by Charles Darwin, I. R.5.
VOL. VIII. m

96 The President’s Address.

by the microscopical observer that the question of the spon- —
taneous gencration of animals and plants can be set at rest.
As far as the results of present investigation go, there seems
to be no satisfactory evidence that the organisms which we
call plants and animals have had any other origin than or-
ganisms endowed with vital properties similar to themselves;
but as to how far any one of these organisms may differ from
its predecessors through all time, we are in the dark. At
first sight, it looks as if this question of the origin of species
was one that must be for ever veiled from our sight; and if
it had not been raised by an inquirer so competent to judge
of the possibilities of our science, we might have passed by
the challenge unheeded. But we have been invited to ascer-
tain the amount of change of which each individual organism
is capable, and especially to observe how far such changes
impress themselves permanently on the organisms, or series
of organisms, in which it takes place. If by the collation
of past well-observed facts with those which present them-
selves before us at the present day, and allowing the largest
amount of time that can be reasonably demanded, we come
to the conclusion that the higher organisms could be degraded
to the forms of the microscopic Protophyta or Protozoa, or
that these latter could be elevated to the condition of verte-
brate animals, then we ought perhaps to conclude, with Mr,
Darwin, that probably all organisms are derived from a single
prototype. But if, on the other hand, the amount of change
we can observe either of degradation or elevation, or both, is
so limited that no amount of time could account for the di-
versity of forms of animal and vegetable life we see around
us, I thik we are driven back upon the hypothesis of a
special creation of species, without being committed to the
special form or manner of that creation. But, whatever be
the direction in which our opinions lead us, let us not be
hasty in the interpretation of the facts which are presented
tous. Let us observe carefully and cautiously, and record
our observations faithfully, in the full confidence that the
Creator has so endowed the human mind, that it will in the
end reject all that which is false, and only hold that which
is true.

T now call your attention to two papers of high interest, on
the microscopic structure of the nervous system; the one by
Messrs. Turner and Lister, of Edinburgh, the other by Mr.
Lockhart Clarke, of London. To the latter gentleman we
are indebted for our knowledge of a method of preparing
nervous tissue for examination, which has resulted in a much
more accurate knowledge of the details of the structure of the

The President’s Address. 97

nerve tubes and cells than has been hitherto known. I need
not tell you, perhaps, that there is yet much to be learned
with regard to the functions of the nervous system ; and that,
whatever advances the physiologist may make in this direc-
tion, the real relation between function and structure will
only he made by the microscope. Here, then, is a subject
for some of our younger friends to pursue. The fact is, in
waatever direction we turn our eyes, there is still work to be
done ; and I have often thought it would be possible for this
Society to imitate the proceedings of the great French Aca-
demy, and appoint committees to report on researches or on
subjects demanding research, which would give an impetus
and direction to an amount of activity and energy that is
now too often unproductive. It has been the reproach of our
country that, whilst undoubtedly we have the finest instru-
ments in the world, our contributions to micrological science
are not at all in accordance with our superior opportunities
of observation. I hope our Society, as it increases in num-
bers, will do more and more to wipe away this reproach. I
_hope to see our ‘ Transactions ’ increasingly enriched by papers
that will bear the stamp of the excellence of our instruments
upon them, and that the pages of our ‘ Journal’ will have dimi-
nishing space for foreign contributions, on account of the
value of those from our home market.

In my address last year, I brought before you the subject
of the desirability of rendering the microscope available in
our natural history and other museums. No one knows
better than you that he who sees with his naked eye alone
sees but half the world that God has made. With this im-
pression, I suggested the manufacture of a museum micro-
scope on a plan that I find was not at all new, and which has
been now at work in the South Kensimgton Museum for
nearly twelve months. It has so far answered its purpose
that, whilst thousands have looked at the objects to be seen
by its aid, the instrument has not suffered in its arrangements ;
and the Committee of Council on Education have ordered
four of them to be placed in various parts of the Animal
Product and Food collections at the South Kensington
Museum, for the exhibition of objects which cannot be seen
by the naked eye. The only way to gain for society the full
advantages of science is to bring the popular mind, by educa-
tion, into a condition in which it can comprehend the principles

involved in the application of its truths in the manifold
directions of art, industry, and health. The discoveries of
science lose the higher part of their value, unless they become
appreciated and applied by an educated public. It is for

98 The President’s Address.

societies like ours to encourage the extension of scientific
education, to enlist the neophyte in our ranks, and thus to
secure accomplished observers and discoverers, and a public
capable of comprehending and applying their discoveries.

I have thus endeavoured to glance at the work of the year,
and embody the thoughts it suggests; but before I close, I

would remind you of the obligation we are under to the —

Council of the noble Institution within whose walls we have
permission to meet. When obliged to leave our apartments
in Regent Street, at the latter end of our last session, we
obtained the consent of the Council of the Royal Society,

and the Senate of the University of London, to meet im the

large room which they now jointly occupy. We had hoped
that this permission would have been permanent, and I feel
it due to the Senate of the London University to say that,

as far as they were concerned, such permission was granted ; —

but the Council of the Royal Society could not see its way
clear to give up its rooms for our use once a month ; and thus
we were compelled to look for a meeting-room in some other
direction. It was then suggested by Dr. Lionel Beale that
application should be made to the Council for permission
to meet in the rooms of King’s College; and I can bear testi-
mony to the promptitude with which this request was
responded to, and you yourselves are the witnesses of the
readiness with which all the accommodation we require has
been accorded to us. I am also able to state that the Council
of this College has, with the same generosity, placed the
whole suite of rooms at the disposal of the Society for a soirée
on the 11th of April next.

It now remains for me to offer thanks for the courtesy that
I have received on all hands, and for the kind manner in
which I have been assisted by the Council, and supported by
you, in performing the duties of your President. It gives me
great pleasure to resign this chair to one who is so well
entitled to fill it, and whose election is so honorable to the
Society itself. Professor Quekett has worked with us from
the beginning, and much of the success of the Society has
depended upon his exertions. Many of the most valuable
papers in our ‘Transactions’ are the result of his pains-taking
and accurate habits of observation, and he has been our
Secretary for nineteen years. These labours alone would
have entitled him, at your hands, to the position in which you
have this day placed him. But independent of what he has
done for you, as Professor of Histology in the Royal College
of Surgeons of England, as the author of the masterly lectures
which he has delivered from the chair he holds, and as the

Hicxs, on Volvox Globator. 99

- first and ablest historian of the microscope, its structure and
uses, he has pre-eminent claims to be the President of the
Microscopical Society of London. To this post he would
long ago have been elected, had your wishes alone been con-
sulted ; but his devotion to science has entailed upon him one
of its too frequent accompaniments, and that is ill health ;
and this alone is the plea that he has put in against your wish
to make him your President on this occasion. J amsure you
will jom me in wishing that he may be speedily restored to
good health and strength, and that he may never be deterred
from occupying your Presidential chair by the presence of
those bodily infirmities which accompany disease.

The Society then proceeded to ballot for officers and four
members of Council in the usual manner, when the scruti-
neers having made their report, the following were declared
duly elected :

President—Professor Qurxert. Treasurer—N. B. Warp,
Esq. Secretaries—G. E. Buunxtnys, Esq.; M. S. Lee, Esq.

Four Members of Counctil—Dr. Mitiar; J. R. Mummery,
Esq.; Dr. Watiicu; S. C. Wurrsreap, Esq. ;—in the place
of A. Brapy, Esq.; J. Guaisuer, Esq.; H. Pericar, Jun.,
Esq.; J. H. Rozerts, Esq.; who retire in accordance with
the regulations of the Society.

The thanks of the meeting were unanimously voted to Dr.
Lankester, for his services as President during the past two
years.

On the Ama@potp Connpitions of Votvox GiopaTor.
By J. Braxron Hicks, M.D., Lond. F.L.S., &e.

(Read March 14th, 1860.)

Tur effect of the attention paid of late to the histology
of the lower tribes both of the animal and the vegetable
kingdom has been to lessen the number not only of species,
but of whole groups, and to rob zoology of many of its sub-
jects. Perhaps thisis best shown in the case of the zoospores,

100 Hicks, on Volvox Globator.

where whole genera of Monadina, Astasiza, &c., have
been distinctly proved to represent only one of the many
phases of the respective Algze to which they belong. But
that Amaba—the moving and all-devourmg “ sarcode’”—
and Actinophrys with its extemporised tentacles, possessing
some of the very essentials of animal life, should belong to the
vegetable kingdom was scarcely to be expected.

Still we have now on record the results of the careful
observations of three naturalists, which seem to prove that
an Amoeboid phase occurs in the life of many vegetables.

Dr. Hartig* has noticed that the antheridia of Characee,
Polytrichum,and Marchantia, change into Spirillum, Vibriones,
and Monas consecutively; and that from the fusion toge-
ther of a number of these last, bodies are formed undis-
tinguishable from Amewba princeps. He remarks that, by
some means or other, Diatomacez find their way into the
interior of this self-moving mass, within which they circulate
in obedience to the various currents.

Mr. Carter+ has watched the changes in the protoplasmic
contents of the cells im Spirogyra, both conjugatmg and
agamic, from which rhizopodous bodies are produced, some
like Amebe, others becoming precisely similar, in appearance
at least, to Actinophrys sol.

Dr. De Bary, as noticed in the Journal (vol. vii, p. 97),
has lately remarked, in his examination of the Myxogastres,
that the creeping threads of mucilaginous matter, by the
confluence of which the fructifymg mass of thalium is
formed, consist of Sarcode. He also remarks, that the
spores placed in water burst, and their contents escape,
clothed only by a very thin primordial utricle, and furnished
with cilia. These bodies progress as ordinary zoospores, and
by further changes are converted into organisms precisely
like Amebe, from which, eventually, spore-cases are formed.
De Bary, therefore, concludes that the Myxogastres are not
fungi, but animals (allied to Rhizopods), and calls them
** Mycrtozoa.”

A fourth instance of this phenomenon occurred to myself
in the course of some observations on Volvox, six years
since, at the end of the summer, at the time when Volvoxr
globator was changing into V. aureus ; although the appear-
ances I allude to were noticed in V. globator, in its ordinary
form, and in ¢wo stages of its existence.

The first example in which I observed motion in the cell was

* See ‘Journ. of Micros. Science,’ 1856, p. 51.
+ See ‘Annals of Nat. Hist.,’ 1857, p..259.

bedi

Hicks, on Volvox Globator. 101

at an early period, before the young Volvo is fully grown,
at the time when the future zoospores first appear, enclosed
in cells, the final product of segmentation. These zoospore-
containing cells, by contact with their neighbours, are rendered
multangular, and they include about twenty or thirty hexa-
gonal, young zoospores, in close contact, and which are of
many colours, as shown at PI. VI, fig. 12,@,6. When these cells
are detached, they become round, and, (to quote my notes at
the time, “They have a curious power of changing shape,
like an infusorial Proteus, protruding the wall, first at one
side, and then at another, into which protrusions the contents
run” (fig. 12 ¢). The other and more striking instance,
however, was visible in the zoospores themselves at an
advanced age, when some of them enlarge and become :irre-
gular in outline (Fig. 13 @). Some disappear. Some break
up and disperse within the Volvor (sperm-cells?). Some
undergo a process of subdivision (germ-cells?), producing a
group of from two to forty green drops, arranged so that their
apices, with cilia, point externally ; while others enlarge to two
_ or three times their natural size, having many nuclei within,
and variously coloured. When this cell, probably by the
solution of the outer mucilaginous coat, becomes free, it also
possesses the power of moving precisely as does a true Aineba.
Unfortunately, I did not extend my observations so far as to
see if in its progress it included foreign matter,—a point of
much interest ; the conditions, however, above described were
so distinct, that there was no possibility of mistake by confu-
sion with other structures, as | watched these aged zoospores
move away in many instances from their original position,
while it underwent the transition.

To conclude, with Dr. De Bary, that the Myxogastres are
animals, because in some phase of their existence they possess
a self-moving endoplast, seems in our present knowledge to
be premature ; for then must we include the above-mentioned
genera, not excepting Volvor and its congeners in the animal
kingdom,—a step for which botanists are not as yet prepared.
A much better explanation seems to me to be this: that the pro-
toplasmic contents, when deprived of their confining envelope
of cellulose, possess, in common with Sarcode, under certain
circumstances, a power of spontaneous motion in the manner
of an Ameba. It is questionable how far such actions in the
Rhizopodan class are the result of any true consciousness,
_ or whether it is not an involuntary action—a property which
can scarcely be denied to vegetables composed only of endo-
or protoplast; and this would seem to be strengthened by the
fact I have observed, viz., that before protrusion, in the dmeba

102 GREVILLE, on Asterolampra.

and Amoeboid bodies, takes place, a rush of the semi-fluid
contents to the spot can be plainly seen before any bulging
occurs. Whether these Amceboid bodies possess the power of
“eating,” will be a question for future observation.

The above remarks increase the interest connected with the
life-history of Volvox globator, which from analogy we may
suppose to be a zoospore-state of another existence; to which
opinion, indeed, the results of investigations are gradually
drawing us.

A Monograph of the Genus AsteRoLaMpPRA, including Astr-
ROMPHALUS and Sparancipium. By R. K. Greviiie,
LL.D., F.R.S.E., &e.

(Communicated by F. C. 8. Roper, Esq., F.L.S., &c. Read March 14th, 1860.)

Since the publication of my paper on Diatomacez occur-
ring in Californian guano (‘ Mic. Journ.’ vol. vii), some very
interesting materials have been placed in my hands, the
careful study of which has led me to take a different view
than I formerly entertained, of the generic relations of Aste-
rolampra, Asteromphalus, and Spatangidium. The materials
referred to consist of—1. Soundings from the Indian Ocean,
obtained by Captain Pullen, in latitude 5° 37’ south, and
longitude 61° 33’ east, at a depth of 2200 fathoms. This
most remarkable gathering was presented by Mr. Hilton to
Mr. Roper, who very kindly transmitted a portion of it to
myself. 2. A series of slides prepared from some of the de-
posits of the United States, by Mr. E. W. Dallas. 3. A
series of slides prepared by Professor Walker-Arnott, from
the substance known under the name of Monterey stone.

My investigations into the great variety of allied forms
derived from these sources point very decidedly towards a
union of the three genera above mentioned ; and that Asfe-
romphalus and Spatangidium will most naturally take their
place as sections under Asterolampra. I may here candidly
admit that, soon after the publication of my former paper,
I became convinced that I had committed an error in adopt-
ing, under any modification, the genus Spatangidium; an
error which might be traced to my desire to retain, if possible,
a genus established by so distinguished a naturalist as De
Brebisson. For although at first sight, under a moderate
power of the microscope, the difference was so striking as to

GREVILLE, on Asterolampra. 1038

justify De Brébisson in using the terms celluloso-reticulate,

subpunctulate, subgranulate, &c., in order to describe the

relative appearance of the segments under the same magni-
ing power, it was easy to see by sufficiently increasing the
wer that the structure of all was essentially the same.

~ In the preparation of the present communication, I gladly

acknowledge the valuable suggestions I have received from

my friends, Professor Walker-Arnott and Mr. Roper.

‘As some confusion already exists with regard to the names
applicable to the different parts of these discs, it is desirable
that some attempt should be made to regulate them. I ven-
ture, therefore, to propose the following nomenclature, which
will be followed in this paper, and easily understood with the

help of the following diagram :

Fig. 1, diagram of Asteromphalus ; Fig. 2, diagram of Spa-
tangidium. ‘To convert Fig. 1 imto a diagram of Asterolam-
pra, all that is required is to separate the lines cc a little, and
make the ray f as broad as the rest.

a umbilicus, & umbilical lines, ¢ median lines (approximated
umbilical lines), d hyaline area (composed of the united bases
of all the rays), e rays, f median ray, g areolated segments.

A few explanatory remarks may be required with reference
to some of these terms. It has been suggested that “ hyaline
area” is uncalled for, because it is composed merely of the
bases of the rays. This is true, but it is composed of the
bases of the rays collectively, and it will be very convenient
sometimes to be able to define the contour, position, Xc., of
this area. As to the rays themselves, there can be no doubt

SS

j
?
¥

that it is desirable to restrict the appellation to those radi-
ating divisions which, commencing at the umbilicus, are at_
first included between the umbilical lines and are afterwards —
continued in a contracted and linear form between the areo- :
lated segments to the margin. The umbilical lines (‘ sepi-
menta imperfecta,” of Ehrenberg) offer greater facilities for
description than the bases of the rays themselves, and a name
for them could hardly be dispensed with.

Several terms have been suggested for the narrow or
“obsolete” ray which occurs in Asteromphalus and Spatan-
gidium ; but, upon the whole,I prefer that of “median,”
which is as expressive as any of the others, and has the
advantage of having been already used by De Brébisson.
An additional recommendation is, that it enables me to apply
the equally expressive term, “ median lines,” to the two ap- |
proximated lines above the median ray, there being evidently |
some connection between these parts. The position of these —
lines differs in Asteromphalus and Spatangidium. Inthe for-
mer genus they appear as really umbilical lines, approximated
indeed, but still springing, like the rest, from the central
point. In the latter they do not do so, and therefore cannot
strictly be called umbilical lines. In fact, they have no rela-
tion with the other lines in point of radiation. It was,
therefore, desirable to invent a term which should be equally
applicable in both genera. By the term median, then, I wish
to imply the two lines which invariably accompany the me-
dian ray, and only exist in connection with it. We shall see
that much interest attaches to these lines, and that they
afford good discriminative characters.

Without giving the original characters verbatim, the three
genera under consideration are distinguished as follows:

ASTEROLAMPRA, Ehrenb. in ‘ Berl. Monatsbericht, 1844,
p. 73. The valve is strictly circular, with a centrical hyaline
area, which is equally divided by lines (* sepimenta”) radi-
ating from the umbilicus. Each of these lines terminates at
the base of a marginal areolated segment, while alternating
with them the rays are continued between the segments to
the margin.

Asrprompnatus, Ehrenb. in ‘ Berl. Monatsbericht,’ 1844,
p. 198. ‘The valve is exactly circular, with a centrical hyaline
area; but, instead of being equally divided by the lines
(“sepimenta imperfecta”) which radiate from the umbilicus,
two of them are approximate and parallel; and instead of all
the rays being equal, one of them is much narrower than the
rest, or, as Ehrenberg calls it, “ deficiens vel ita obsoletus.”

SPaTANGIDIuM, De Bréb. ‘Bull. de la Soc. Linn. de Nor-

104 GREVILLE, on Asterolampra.

het ip Mla a al es: OP

.

GREVLLLE, on Asterolampra. 105

mandie,’ 1857. The valve is “ suborbicular,” and the “ poimt
@ou rayonnent les ambulacres . . . + est toujours ex-
centrique.”’

It will be perceived that if we take a frustule of Astero-
lampra (which may be assumed as the typical form of the
group), and merely approximate two of the umbilical lines,
so as to become parallel, and make the ray between them
narrower than the rest, we have at once an Asteromphalus ;
and that between the latter genus and Spatangidium there is
only (according to De Brébisson’s view) the eccentrical post-
tion of the hyaline area, with its lines and rays. Again, if
we take the genus Asterolampra as our stand-point, and
examine in what respects Ehrenberg has made Asteromphalus
to differ from it, we are reduced to the conclusion that the
former rests its claim to generic distinction, as compared
with the latter, on the sole circumstance that the rays and
umbilical lines are all equal.

Let us now examine how far these genera have been
affected by recent discoveries. In Asterolampra the species
named Marylandica was the only one known to Ehrenberg ;
and though various others have been subsequently described,
they must all be referred to that species. In all of them the
areolated segments are concave at the base, and the umbilical
lines straight and simple. But other species, very different
in habit, must now be introduced on the claim specified in
the close of the last paragraph. One of these is Asterom-
phalus Grevillii, of Wallich,* from the Indian Ocean, found
also by Mr. Dallas in the Rappahannock deposit, United
States, and by Professor Walker-Arnott in Monterey stone ;
in which the numerous segments are square at the base, and
the umbilical lines are variously divided. In A. variabils,
another species found in the same material, the umbilical
lines are most of them divided near to the central point,
being either forked or arranged in triplets; while the base of
the segments is so sharply angular as to give a triangular
aspect to the adjoining portion of the rays.

In a third species from the same source (A. Brébissoniana,
Pl. II], fig. 9), the numerous segments are square at the base,
and the umbilical lines exhibit the angular bend in the mid-
dle, which is observable in certain species both of Asterom-
phalus and Spatangidium. It is impossible not to perceive
how strongly the characters and natural habit of the diatoms
noticed above run into those of the last-named genera.

Asteromphalus, as we have already seen, only differs (ac-

my

* «rans, Mic. Soc.,’ vol. viii, p. 47, Pl. 2, fig. 15.

f
al
cording to Ehrenberg himself) from Asterolampra in two of
the umbilical lmes common to both genera becoming approxi-
mate and “ parallel,” and in one of the rays common to both
genera becoming narrower than the rest. But even this dif-

106 GREVILLE, on Asterolampra.

ference is not strictly maintained in all Ehrenberg’s own

species ; forin A. Darwinii and A. Rossii the median lines

are not “parallel,” but cuneate. This deviation from the ;
generic character is still more prominent in recently disco-—

vered species, which, notwithstanding, cannot be excluded

from this place. In my <Asterolampra Dallasiana, for ex-—

ample (Pl. IV, fig. 10), the median lines are campanulate ;
and in my Asterolampra Wallichiana (fig. 11), they are

so widely cuneate as to show a decided approach to Aste-
rolampra as restricted by Ehrenberg. It is evident, therefore,

that were the genus to be sustained, the character derived :

from the parallelism of these lines would have to be aban-
doned. With regard to the form of the segments, they are
represented as concave at the base in all Ehrenberg’s species.
In Asterolampra Dallasiana and <A. Wallichiana, however,
they are square at the base. The angular bend in the umbi_
lical lines which marks some species of Asterolampra and
Spatangidium is found also in Asteromphalus in one or two
instances,

I have remarked elsewhere—and am glad to see that my
view is supported by Dr. Wallich—that the character on
which De Brébisson founded his genus Spatangidium, viz.,
the eccentrical position of the hyaline area, is far too uncer-
tain to be relied on; for valves are continually occurring in
which this feature is scarcely, if at all, perceptible. And
when this character disappears, so also does the “ sub-orbicu-
lar”’ form of the valve. How little dependence can be placed
upon it is well shown in S. heptactis of De Brébisson (S.
Ralfsianum of Norman, in my former paper). De Brébisson
does not state the form in his description, but his figure
represents it as broadly ovate, whereas in mine it is the very
reverse.* An exception, however, appears to exist in Spa-
tangidium Arachne, which, as far as 1 have observed, retains
constantly its round-ovate outline, as well as its highly eccen-
trical arrangement. A better generic character than the
latter might have been found for Spatangidium, as Professor
Walker-Arnott has suggested, in the median lines (Dr. Wal-
lich’s basal ray) passing over and beyond the central point,
so as to cause the umbilical lines to radiate from the top and
sides of the median lines, and not from the central point

* «Mie. Journ.,’ vol. vii, Pl. 7, fig. 8.

S

GREVILLE, on Asterolampra. 107

itself, as in Asteromphalus. A most remarkable species, how-
ever, belonging to the Indian Ocean soundings—my Astero-
lampra Roperiana (P1.1V, fig. 14)—seems to form a connect-
ing link, not only between these two genera, but including the
Asterolampra of Ehrenberg itself. It will be seen at a glance
that the plan, so to speak, of the valve is far more that of
Asteromphalus than of Spatangidium. In the circular out-
line, in the centrical hyaline area, radiation of the umbilical
lines, approximation of the median lines, and in the median
ray, it is an Asteromphalus. In the single circumstance that
the median lines pass slightly beyond the central point, form-
ing a little imperfect circle round it, is the frustule, a Spa-
tangidium. The median lines in this species present some
additional curious features. But for the intervention of the
little imperfect circle, which may be compared to the nave of
a wheel, the umbilical lines would meet at precisely the
central point. Immediately beneath the imperfect circle the
median lines contract into a sort of neck, and then, instead
of continuing to be approximate, as they ought to do for a
Spatangidium, or parallel, as Ehrenberg would require of them
for an Asteromphalus, they diverge, and by a curve reach the
edge of the hyaline area at points almost equidistant between
themselves and from the adjoining umbilical lines. In this
last character (sub-equidistance of the termination of the
median lines), as well as in the sub-equidistance of all the
rays, the median one included, the frustule is very nearly an
Asterolampra. The valve in my Asterolampra Shadboltiui is
also circular, and, but for the median lines passing slightly
beyond the central point, would in every other respect belong
to the Asteromphalus section. In Asteromphalus Brooket,
likewise, of the late Professor Bailey, the valve, if not actually
circular, appears to be so to the eye, and the median lines,
which somewhat resemble those of Asterolampra Roperiana,
scarcely pass beyond the central point. Enough has been
said, perhaps, to illustrate the transition of these genera into
each other ; and we may now proceed, in accordance with the
views advocated, to give a systematic arrangement of the
known species.

Asterotampra, EKhrenb.

AsTEROMPHALUS, Ehr. Sparanerpium, De Bréb.

Frustules simple, two-valved, disciform. Valves orbicular
or sub-orbicular (in one case oblong) ; central area hyaline,
and furnished with radiating lines, each of which terminates
at the base of an areolated marginal segment ; while, alter-

108 GREVILLE, on Asterolampra.

nating with them, transparent rays are continued from the
hyaline area between the segments to the margin.

Section I.—Rays equal and equidistant: AsTEROLAMPRA.

1. Asterolampra Marylandica, Ehr. Umbilical lines simple,
straight ; areolated segments curved at the base. Diameter
‘0016" to 0080". (Pl. III, figs. 1—4.)

Asterolampra Marylandica, Ehr. Berl. Monatsbericht, 1844, p. 76,
Pl. (June), fig. 10. Bail. Sill. Journ., vol. xlviii, Pl. 4, fig. B.
Kutz. Sp. Alg., p. 129. Pritch. Animale., p- 320, Pl. 14, fig. 33.
Mic. Dict., p. 71, Pl. 19, fig. 5. Wall. Trans. Mic. Soe., vol. viii,
p. 47, Pl. 2, figs. 13 (6 rays), 14(7 rays). Brightw. Mie. Journ.,
vol. vill, Pl. 5, fig. 3 (6 rays). a

A. septenaria, A. 8. Johns. Sill. Journ., 2d ser., vol. xiil, p. 33.

A. impar, Shadb. Trans. Mie. Soc., vol. ii, Pl. 1, fig. 14 (7 rays). ,

A. pelagica, Ehr. Berl. Monatsbericht (1854), p. 238. _ (Noticed
first by Miller, Abhandl. d. Berl. Akad. 1841, vol. i, p. 232,
PL. 6, fig. 4, in his Memoir tiber den Bau des Pentacrinus caput
Medusee (7 rays).

Hab. Various deposits in the United States (6 to 9 rays).
West Indies (7 rays), R. K. G. Natal (7 and 11 rays), Shad- —
bolt. Monterey stone (7 rays), Professor Walker-Arnott.
Indian Ocean, from Salpe (6 and 7 rays), Wallich. Indian
Ocean soundings, at 2200 fathoms (6 rays).

This species is exceedingly variable ; and, notwithstanding
the number of figures which have been given of it, several of
which, however, are merely repetitions of each other, I have
considered it very desirable to offer some additional ones, in
order more fully to illustrate deviations from what may be
regarded as the typical form, well represented by Ehrenberg’s
original figure. That author has assumed eight as the normal
number of the rays, and he is probably correct with reference
to the frustules found in the American deposits. I believe
that number to predominate, although specimens with from
six to nine rays also occur in the same deposits. It is at the
same time a very curious fact, that in the Indian Ocean
soundings every example which has come under my notice
possesses Only six rays; and Dr. Wallich has represented one,
likewise with that number, obtained from Salpe in the Bay
of Bengal. While thus the number eight appears to predo-
minate in the American deposits, and six in the Indian Ocean
(so far as known), an odd number, seven or eleven, was found
by Mr. Shadbolt to exist exclusively in a gathering from Port
Natal. It would be rash from such limited data to conclude
that these are the prevailing numbers on the coast of East
Africa ; still it is remarkable, that in the gathering specified,

GREVILLE, on Asterolampra. 109

with the frustules “‘ moderately abundant,” not one should
have been observed having other than seven or eleven rays.
The extreme range appears to be from six to twelve; Dr.
Waliich refers to one in his possession, without mentioning
the locality, containing the latter extraordinary number. It
is, however, now admitted on all hands that the number of
rays is of no diagnostic value whatever ; and, consequently, it
is necessary to bring together all those so-called species which
have no other character to rest upon. Among the examples
which I have given in Plate III, are frustules with six, seven,
and nine rays; but I have not selected these forms on account
of this variation, but in order to show how widely the valves
may otherwise differ, and to assist in determining the ques-
tion of identity. In fig. 1, from Piscataway, Maryland, the
yays are not only numerous, but the segments form an ex-
tremely deep curve; and in Dr. Wallich’s figure, 14, 1. c.,
the same effect is produced with fewer rays, in consequence
of the segments being carried still nearer to the umbilicus.
In my figure 3, detected by Mr. Dallas in ‘ Bermuda Tripoli,”
the species seems to have reached the very opposite extreme,
and its most aberrant condition. The hyaline area is so large
as to occupy half the radius; and the curve of the areolated
segments is not only very shallow, but ceases to be regular,
being considerably flattened; all which makes the rays appear
so short, that they might be compared to the handles of a
steering-wheel. I have introduced figure 2, from Rappahan-
nock, to show that while the hyaline area occupies even a
larger portion of the valve than the preceding, the segments
preserve the true curve. The valve has seven rays, and pre-
sents a most striking contrast to Dr. Wallich’s fig. 14, l. ¢.
My fig. 4 represents a frustule from the Indian Ocean sound-
ings, remarkable for its gigantic size. It exhibits also a pecu-
liarity, observable in all the specimens, obtaimed from the
same quarter,—a greater breadth of the ray than usual. The
umbilical limes may be said to be normally simple in this
species ; but one or two of them are occasionally forked close
to the central point, as seen in fig. 1.

With regard to the nature of these lines, it is improbable
that they indicate an actual division or dissepiment between
the bases of the rays, as such a provision would seem to be
useless while the remaining portion of those organs is so
firmly united to the adjoming parts. In the numerous frac-
tured specimens of Asterolampra and Spatangidium I have
examined, I have never been able to trace any disposition in
the valve to break up in the direction of these lines. The
more correct view, it appears to me, is that suggested by Mr.

110 GREVILLE, on Asterolampra.

Roper, viz., that they are raised and thickened lines, tended —

to strengthen the valve. In a frustule of A. Marylandica, to
which he drew my attention as throwing some light on the
subject, a portion of the hyaline area has been accidentally
destroyed, leaving one of the lines denuded throughout its
whole length. From its evident strength, it is admirably
adapted to the purpose assigned toit by Mr. Roper. Indeed,

the hyaline area, in all these diatoms, may not be unaptly —

compared to a circular window, with radiating bars, fitted

with transparent siliceous panes. In several species of this —
and the following sections, there is an apparent thickening —
in the rays, especially where they pass the confines of the —
hyaline area. At this part there is sometimes a sort of ridge —
or convexity, which gradually subsides into the plane surface —
of the basal portion of the ray. This appearance is indicated

in Mr. Shadbolt’s figure already quoted, and is probably
caused by an internal channel, the termination of which, near

the umbilicus, is occasionally tolerably evident ; but I do not

find anything like the line passing down the middle of the
ray, as faintly seen in Mr. Shadbolt’s figure, and conspicu-
ously in that given by Mr. Brightwell. (‘ Mic. Journ.,’
vol. viii, pl. 5, fig. 3.) That the rays are tubular, seems to be
confirmed by Dr. Wallich, who finds air-bubbles in them in
some of his balsam-mounted slides. It is now well known,
that the two valves of the frustules of this group do not cor-
respond in the disposition of the rays, or, to use a printer’s
phrase, they do not register; but that the ray of one valve

is opposite to the areolated segment of the other,—a cireum- —

stance which, to an mexperienced observer, is often not a
little perplexing. This arrangement was first noticed by
Miiller, who, in fact, figured the two valves of Asterolampra
in their normal position, before Ehrenberg himself constituted
the genus. He remarks, “ Dieser Stern ist eme Doppelfigur
und besteht aus eimem vordern und hintern stern, woven
jeder 7 Strahlenhat, die Strahlen des hinteren stehen in den
Zwischenraumen der Strahlen des vorderen.’”’*

It is a curious fact, that im species where the umbilical
lines are more or less branched, those of the two valves do
not necessarily correspond. In a beautiful frustule in my
possession, of Asteromphalus Brookei of Bailey, the upper
valve is so convex that the umbilical lines can be focused
distinctly from those of the lower flat valve, and it appears
that the fureation of the two sets of lines is to some extent
different. This tends to confirm Mr. Roper’s idea above-

* Abhandl. d. Berl. Akad. (1841), vol. i, p. 282.

GREVILLE, on Asterolampra. il}

mentioned, that these lines are to be considered mainly as
ribs or bars of support. No species has so wide a range with
regard to size as A. Marylandica. The smallest that has
come under my notice is a specimen belonging to Mr. Roper,

of Shadbolt’s A. impar, which is only ‘0018.

2. Asterolampra Rotula, n. sp. Grev.—Areolated segments
nearly square at the base; umbilical lines simple, or forked
close to the central point. Diameter -0044". (Pl. ITI, fig. 5.)
_ Hab.—Monterey stone, Professor Walker-Arnott.

Tt is with considerable hesitation that I venture to offer
this diatom as distinct from the following, and should not
have done so but for the opportunity afforded me by Professor
Walker-Arnott, of imspecting a series of that species. I
find, on a close examination, and after making drawings of a
number of specimens, so uniform an adherence to the cha-
racter furnished by the base of the segments, that I cannot
at present bring myself to regard the present form as a
variety. At the same time it may be held as only provision-
ally independent. The segments are somewhat square at the
base, and the lmear portion of the rays commences abruptly
at the margin of the hyaline area; whereas, in the following
species, the linear portion of the rays assumes a triangular
figure before leaving the hyaline area, in consequence of the
very different outline of the base of the segments. The
umbilical lines of the two are much alike; those of the
species under consideration showing a disposition to divide.
It will be perceived that one of them, immediately after
leaving the central point, separates into three branches.

3. Asterolampra variabilis, nu. sp. Grev.—Areolated seg-
ments, with a dipping angle at the base; upper part of the
basal portion of the ray triangular; umbilical lines simple,
forked, or in triplets. Diameter ‘0028” to -0048” (Pl. ITI,
figs. 6—8.)

Hab.—Monterey stone, Professor Walker-Arnott.

The most characteristic feature, as I conceive, of this
diatom, arising from the form of the basal portion of the
rays, and consequent angular base of the segments, has been
referred to in my remarks on the preceding species. The
result of this character is a very beautiful rosette-like contour
of the hyaline area, and constant in all the specimens I have
seen. The umbilical lines, also, are remarkable. I A.
Marylandica they are, as we have seen, normally simple,
being rarely (one or two only) forked. In the species now
before us, the reverse is the case. In the great majority of
instances the lines are forked or in threes; so that in the
same valve there will seldom be more than two of them un-

VOL. VIII. n

112 GREVILLE, on Asterolampra.

divided. In the series already referred to, as communicated
by Professor Walker-Arnott, the following arrangements of
these lines occur. (1.) In a valve with seven rays, one
line is simple, six united in triplets; so that only three
lines actually radiate from the central point. (2.) A valve of
eight rays (fig. 6) : two simple lines and two triplets; four
lines therefore radiate from the central point. (3.) Another
valve with eight rays: one simple line, two forked and one
triplet; four lines, as before, radiating from the centre, but
by a different combination. (4.) A valve with nine rays
(fig. 7): two simple lines, two forked and one triplet; in
this case the divisions occur at a considerable distance
from the umbilicus, and five lines emanate from the central
point. (5.) A valve with ten rays: no simple line at all, but
two forked and two triplets; only four actually radiating
from the centre. (6.) A valve with eleven rays (fig. 8);
one simple line, two triplets, and one quadruplet; still only
four proceeding directly from the umbilical point. It willbe
obvious from the above statement, that there is a decided
tendency in the umbilical lines of this species to arrange
themselves in triplets. I regret that I have not space to
admit of the entire series being engraved, but the examples
I have selected will afford a good idea of the whole. It is
worthy of observation that the valve I have represented at
figure 6 seems, on a momentary glance, to possess what I
have called median lines, which enclose Dr. Wallich’s “ basal
ray” (“from the true rays being always arranged around or
upon it”) ; but this is a deception. Median lines, according
to my view, cannot exist apart from a median ray, and con-
sequently are not to be found in this section of the genus.
In the present instance it will be perceived, by a comparison
with figures 7 and 8, that the appearance is caused by two
triplets of umbilical lines happening to adjoin each other.
The same effect is twice repeated in figure 8, only not quite
so conspicuously. Dr. Wallich proposes to substitute the -
term “basal” ray for median or “ obsolete”? ray ;* but as
there is no instance on record of more than one median ray
occurring in the same valve, he must use the term in a more
enlarged sense in his highly interesting paper, when he
ascribes three basal rays to the species he has done me the
honour to associate with my name. In one of Professor
Walker-Arnott’s slides is an abnormal valve of A. variabilis
with the hyaline area very eccentrical, and the whole havin

exactly the appearance as if it had been intended for a

* ‘Trans, Mic. Soc.,’ vol, Vill, p, 45,

GREVILLE, on Asterolampra. 113

Spatangidum. It has six rays, the lower one much the
longest ; the upper one short, and the lateral ones slightly
curved downwards. This accidental deviation from the
ordinary arrangement of the valve in this species is imma-
terial, except as an additional illustration of the tendency
in individuals belonging to the different sections of the
group to partially assume the general appearance of each
other.

4. Asterolampra Grevillit.—Areolated segments square at
the base; rays numerous; umbilical lines divided and ar-
ranged in parcels or groups of from two to five lines each.
Diameter about -0034”. (Pl. IV, fig. 21, an abnormal
valve.)

Asteromphalus Grevillii, Wall. Trans. Mic. Soc., vol. viii, p. 47, Pl. 2,

fig. 15

Hab.—Rappahannock Deposit, United States, Mr. E. W.
Dallas. Indian Ocean, Dr. Wallich. Monterey stone,
Professor Walker- Arnott.

The uniform character of the rays brings this species into
the present section. The examples originally discovered by
Mr. Dallas, and which I had described in MS. as unques-
tionably distinct, I have little or no hesitation in now referring
to this place. Although no character can be strictly drawn
from the number of rays, yet it would seem that in this
diatom they are so numerous as to give it a peculiar appearance.
The umbilical lines, as they radiate from the central point,
are very few; but they almost immediately divide in such a
way, that a group of lines seems to be supported, as it were,
by a single short stalk. The frustule figured by Dr. Wallich
has thirteen rays; the umbilical lines are combined into
three groups ; the three little stalks which support them alone
radiating from the central point. One of the American
specimens, of which I had prepared a drawing, contains
fifteen rays; and the umbilical lines are combined into four
groups, supported by as many little stalks. Another of the
American specimens contains seventeen rays. The one with
fifteen rays has four, which Dr. Wallich would call “ basal ;”
that is, they unite at the umbilicus exactly in the same
manner as do his three “‘ basal rays” in his figure of the
present species. Consequently, if I am right in considering
the American and Indian individuals as identical, the species
might be said to possess an indefinite number of such rays.
But, as I have already remarked, this arrangement of the rays
admits of a different and more satisfactory explanation. - At
figure 21 (Pl. IV), I have introduced a valve, from the

114 GREVILLE, on Asterolampra.

Indian soundings, having a very irregular and curious arrange-

ent of the umbilical lines. ,

. 5. Asterulampra Brébissoniana, n. sp. Grev.—Areolated
segments square at the base ; umbilical lines with an angular
bend in the middle. Diameter ‘0030’. (Pl. II, fig. 9.)

Hab.—Monterey stone, Professor Walker-Arnott.

This may be regarded as one of Professor Walker-Arnott’s
most interesting discoveries, as it shows that the very remark~
able angular bend in the umbilical lines, already known to
exist in some species of Asteromphalus and Spatangidium,
is not excluded from the present section; and therefore
strengthens, in however small a degree, the argument in
favour of the union of the whole group into one genus. I
have much pleasure in dedicating so well-marked a species to

M. Alphonse de Brébisson, whose name is so eminently asso- —

ciated with these wonderful structures.

Section IJ.—Rays unequal (one much narrower than the
rest). Umbilical lines radiating from the central point ; two
of them approximated.— AsTEROMPHALUS.

6. Asterolampra Hookerii.—Ayreolated segments curved at
the base ; umbilical lines straight, the two approximated ones
(median lines) parallel.

Asteromphalus Hookerii, Ehr., Berl. Monatsb., 1844, p. 200, pl. (June),
fig. 3; Kiitz., Sp. Alg., p. 129; Pritch., Animale., p. 321; Mie.
Dict., p. 71, pl. xix., fig. 2; Ehr., Mikrogeol., pl. 35, A. xxi., fig. 2
(6 rays).

Asteromphalus Buchii, Ehr., Berl. Monatsb., 1844, p. 200, fig. 4;
Kiitz., lc. p. 130; Pritch., |. ¢., p. 321;. Mic. Dict., p. 71 7
rays).

anterantalas Humboldtii, Ehr., Berl. Monatsb., 1844, p. 200, fig. 6;
Kitz., l.c., p. 130; Pritch., 1. c¢., p. 321, pl. xiv., fig. 34; Sie
Dict., p. 71; Ehr., Mikrogeol., pl. xxxv., A. xxi., fig. 3 (8 rays).

Asteromphalus Cuvierii, Ehr., Berl. Monatsb., 1844, p. 200, fig. 7;

Kiitz., l. ¢., p. 180; Pritch., 1. ¢., p. 321; Mie. Dict., p-71; Ehr.

Mikrogeol., pl. 35, A. xxi., fig. 1 (9 rays).

Hab.—The Antartic Ocean, Dr. J. D. Hooker.

As the celebrated Ehrenberg regarded a simple difference
in the number of rays as amounting to specific distinction,
he has added a multitude of names to our list of Diatomacez
which cannot now be permitted to retain their position.
Such is pre-eminently the case in the genera Actinocyclus and
Actinoplychus, which will probably be found ultimately to
contain comparatively few true species. In Asteromphalus the
same system was carried out. The four species now brought
together are only distinguished by each individual having

=?

;
:

GREVILLE, on Asterolampra. 115

one more ray than its predecessor. In every other respect
they are precisely similar.

7. Asterolampra Dallasiana, nu. sp., Grev.— Areolated seg-
ments square at the base; umbilical lines straight ; median
lines campanulate. Diameter -0038". (Pl. IV, fig. 10.)

Hab.—In “ Bermuda Tripoli,’ Mr. E. W. Dallas.

The diatomist cannot fail to observe how similar this form
is to some of the species described in the first section, with
the exception only of the median ray and median lines. In
general habit it is widely different from all the Asteromphali
of Ehrenberg, but agrees more with the following species,
also detected by my lynx-eyed friend, Mr. Dallas, in the
same material. The precise locality of this famous “ Tripoli”
was for some time a mystery ; but the readers of the ‘ Micro-
scopical Journal’ will be aware that Professor Walker-Arnott
believes that he has traced it to a place called Bermuda,
about twenty miles below Richmond in Virginia.* Con-
sidering that the genera Heliopelta, Craspedodiscus, &c., have
never been found elsewhere, it may be said to be the most
precious deposit known; and the discovery in it of two new
species of the present section of Asterolampra will add not
a little to its interest. It is remarkable, however, that if it
really forms a part of the great Richmond deposit, nothing
like it should have been found since the original supply
passed into circulation.

8. Asterolampra Wallichiana, n. sp., Grev.—Areolated seg-
ments square at the base; umbilical lines straight, the two
median one scuneate. Diameter ‘0021". (Pl. IV, fig. 11.)

Hab.—In “ Bermuda Tripoli,” Mr. E. W. Dallas.

Only one specimen of this species has been seen, and it is
conspicuous for the polygonal aspect of the hyaline area,
which resembles the dise of an Ophiura. There are only six
rays, and the basal portion of each is so wide next the areo-
lated segments, that it may be compared to a short-bladed
trowel, while the linear part represents the handle. These
relative proportions, however, may not be constant.

9. Asterolampra Beaumontii—Areolated segments curved
at the base; umbilical lines with an angular bend; median
lines straight, parallel.

Asteromphalus Beaumontii, Ehr., Berl. Monatsb., 1844, p. 200, pl.
(June), fig. 5; Kitz, 1].¢, p.1380; Pritch., Le, p. 321; Mic.
Dict., p. 71, 2d edit., Pl. 43, fig. 15.
Hab.—Antarctic Ocean, Dr. J. D. Hooker.

* ‘Mic. Journ.,’ vol. vii, p. 254.

116 GreviLLy, on Asterolampra.

A very singular species, having the ordinary umbilical
lines furnished with an angular bend in the middle, while
the median lines are straight. It thus forms a transition
from the previous species of the section to the following one.

10. Asterolampra Darwinii.—Areolated segments some-
what square at the base; umbilical lines with an angular
bend ; median lines cuneate, with an angle midway, furnished
with a minute spine-like projection. Diameter 0019" to
0035". (PI. IV, figs. 12, 13.)

Asteromphalus Darwinii, Ehr., Berl. Monatsb., 1844, p. 200, pl. (June),
fic. 1; Kiitz., 1. ¢., p. 129; Pritch., l. ¢., p. 320; Mic. Dict., p. 7]
(5 rays).

Asteromphalus Rossii, Ehr., Berl. Monatsb., 1844, p. 200, pl. (June),
fig. 2; Kitz. 1c, p. 180; Pritch., |. ¢, p. 321; Mie. Dict.,
p. 71; Ehr., Microgeol., pl. 35, A. xxi, fig. 4 (6 rays).

Hab.—Antarctic Ocean, Dr. J. D. Hooker. Monterey
stone, Professor Walker-Arnott.

The determination of this species has been accompanied —

with a good deal of perplexity. The figures given by Ehren-

berg represent the base of all the areolated segments as—

curved—not in the remotest degree as tending to square ;
whereas in the specimens obtained by Professor Walker-
Arnott from the Monterey stone (all of them four-rayed), the
hyaline area is decidedly quadrangular. Nay, more than
that, the outline of the hyaline area between the median and
adjoining rays is slightly but unequivocally convex instead of

concave. It is difficult to conceive how so great an amount
of error should have crept into Ehrenberg’s figures, if the

Monterey specimens be really the same. I confess that I
am not quite satisfied on this point, although the umbilical
and median lines agree. In deference, however, to Professor
Walker-Arnott’s opinion, I refer his Monterey valves in the
mean time to this place, and offer representations of two
examples, in order that the discrepancy between them and
Khrenberg’s figures may be better understood. It will be
noticed that there is some difference in the median lines in

the two valves; but the absence of the angles in figure 13°

may be regarded as accidental.

_ Section I11.—Rays unequal. Umbilical lines radiating
from the top and sides of the median lines; which latter pass
beyond and enclose the central point.—SpaTanGIDIUM.

sate Lots
* Umbilical lines without an angular bend.

11. Asterolampra flabellata.—Areolated segments curved

~

GREVILLE, on Asterolampra. 117

aR!
.
4

at the base; umbilical lines all straight, radiating from the
apex and sides of the median lines. Diameter ‘0017” to
7 “0024”.
i
Spatangidium flabellatum, De Bréb., Bull. Soe. Linn. de Normand.,
vol. iii, Pl. 3, fig. 3.
ep rmalos flabellatus, Grev., Mic. Journ., vol. vii, p. 160, Pl. 7,
gs. 4, 5.
Spatangidium peltatum, De Bréb., |. ¢., Pl. 3, fig. 4.

Hab.— Peruvian Guano, De Brébisson. Californian Guano.
_ After a reconsideration of the claims for distinction put
forth on behalf of the two diatoms above quoted, I cannot
find any really trustworthy characters to separate them. The
slightly arcuate rays in S. flabellatum will not alone suffice, as
this appearance may be seen occasionally in species whose
rays are normally straight ; and the “ subpinnate ”’ disposition
of the rays in S. peltatum is rather a deception, arising
simply from the number being uneven, and the odd ray
being placed on the apex, in the direction of the median lines.
Beyond these two characters—the one as uncertain as the
other—there is nothing to rest upon. The number of rays in
the specimens I have scen is ten or eleven; but a larger
series of examples would probably show a wider range. The
_areolation is very minute.
12. Asterolampra Hiltoniana, n. sp. Grev.—Areolated seg-
ments acutely curved at the base; umbilical lines radiating
from the apex and sides of the median lines, the two lower
pair suddenly defiexed. Diameter 0038” to 0052”. (PI. IV,
fig. 15.)
Hab.—Algoa Bay Guano, R.K.G. Indian Ocean soundings,
made by Captain Pullen.
_ Ona former occasion, this species was referred to by me as
probably distinct ;* but at that time I had only seen two
examples with ten rays each. In the Indian soundings I
have met with numerous individuals (including fractured ones,
which are often equally instructive), and my previous im-
pression is fully confirmed. The latter specimens are much
finer, the rays varying from fifteen to nineteen. Three of
the umbilical lines on each side are generally deflexed, but
the lowest two on each side are more or less suddenly bent
downwards in the middle, either by a sharp curve or angle.
In the African specimens the lines are all simple. So are
_ they all in an Indian valve of eighteen rays. In the Indian
one, however, which I have figured, with nineteen rays, three
_ of the lines are forked. It is a very transparent species, and
"

’

* «Mic. Journ.,’ vol. vii, p. 160.

118 Grevit_e, on Asterolampra.

easily overlooked. The rays are slender, and the areolation
SS * ® Umbilical lines with an angular bend.

13. Asterolampra elegans, Grev.—Areolated segments
sharply curved at the base, morethan half theradius; umbilical
lines radiating from the apex and sides of the median lines,
normally simple, but sometimes once or even twice forked.
Diameter 0030" to -0060". (Fig. 16.)

elegans, Grev.,’ Mic. Journ., vol. vii, p. 7, Pl. 7, fig. 6,
Aste ‘Trans, Mie. Soc, vol. vik p. 46, Pl, 2, fg 108 i

Hab.—-Californian Guano. Soundings from the Indian
Ocean, in 2200 fathoms, made by Captain Pullen.

My figure formerly published represents a small normal
example; but the specimens which occur in the Indian
soundings present so extreme a deviation from the typical
state, that an additional illustration becomes absolutely
necessary. In most of these Indian valves there is a disposi-
tion in the umbilical lines to divide, or even subdivide; and
this is done so irregularly that simple lines may be mixed
with the forked ones. In three specimens now before me,
the first, with seventeen rays, has three of the lines forked and
one twice-forked. The second, with twenty rays, has four
forked and one twice-forked. The third, a magnificent and
perfect specimen, with twenty-five rays (fig. 16), has seven
lines forked and one twice-forkéd ; so that only five of the
lines remain in their normal condition. A large specimen
in Mr. Roper’s cabinet, of which he has sent me a drawing,
exhibits a still more whimsical aberration. It has twenty- |
nine rays, but only ten umbilical lines radiate directly from
the median lines; of these, one is divided into six, another
into seven branches. Four lines only are simple. In the
sketch of another valve contaming twenty-five rays, sent by
Mr. Norman, six lines are simple. In these anomalous valves
the angular bend becomes less conspicuous, because the
ramification generally takes place at one or both angles of the
bend ; a fact which rather tends to strengthen my remark
under A. heptactis, that where the angular bend exists, a
ramulus however fine, or at least a disposition. to origimate a
ramulus, may be also presumed to exist. The areolation of
this species is extremely minute, and the rays are gracefully
slender. I have some scruples about referring the valve,
which Dr. Wallich has figured, to this place, without an
opportunity of tracing its connection. The peculiar-looking
median lines, robust rays, and apparently rather large areola-
tion, seem to indicate a difference.

GREVILLE, on Asterolampra. 119

14. Asterolampra imbricata.—Areolated segments, sharply
curved at the base, less than half the radius; rays numer-
ous, robust; angular bends of the umbilical lines forming
unitedly an oblong elliptical figure. Diameter 0024” to
"0034". (Fig. 17.)

va ae imbricatus, Wall., Trans. Mic. Soc., vol. ‘viii, p. 46,

Hab.—Salpe, Bay of Bengal, Dr. Wallich. Soundings
from the Indian Ocean, in 2200 fathoms, made by Captain
Pullen. Natal, Mr. Roper.

One of the most distinct and beautiful species I am ac-
quainted with. The appearance of the valve is singularly
rich, the usual parts being so arranged as to present suc-
cessive series of radiations. The umbilical lines are given
off from the top and sides of the median lines in such an
equal, symmetrical manner that the angular bends are in
close and parallel approximation. The oblong-elliptical line
thus formed, taken at its widest part, is about a third of the
radius, and constitutes what may be called the first zone in
the radiation. The continuation of the umbilical lines to
the base of the segments, taken along with the enclosed
basal portions of the rays, forms a second zone; and the
narrower portion of the rays, with the areolated segments, a
third zone. As all the specimens which I have examined
differ somewhat from Dr. Wallich’s figure, [ have thought it
desirable to give a supplementary one, of a valve with
twenty-one rays. I have another drawing of an equally
perfect valve, with seventeen rays, in all respects similar. In
my valves the median lines taper down beautifully to the
median ray, and exhibit an abortive angular bend at the
proper place. The most material difference, however,
between Dr. Wallich’s figure and my specimens consists in
the wide space represented by him between the two lowest rays
and the median ray ; whereas in my extensive series of valves
there is no greater space than there is between any of the
other rays; indeed, in most frustules, the space is rather
less. The outline of the valve is slightly, but perceptibly,
ovate ; the areolation considerably larger than in A. elegans,
its nearest ally. It is the most robust species which has
occurred in the Indian soundings, and hence, perfect indivi-
duals are not quite so rare as in other cases. Among Mr.
Roper’s drawings is one of a valve from Natal, with only ten
rays, and in diameter only ‘0015. In all material charac-
ters, however, it agrees well with the present species.

15. Asterolampra Brookei.—Valve nearly quite circular ;

120 Grevitie, on Asterolampra.

areolated segments nearly square at the base; angular bend
of the umbilical lines situated towards the outer extremity ;
median lines scarcely passing beyond the central pomt,
arched at the top, then contracted, afterwards more or less
divergent. Diameter ‘0028” to 0036". (Fig. 18.)

Asteromphalus Brookei, Bail., Sill. Journ., 2d ser., vol. xxii, p. 2, PET
fig. 1.

Hab.—Sea of Kamtschatka, in soundings made by Lieut.
Brooke, in 1700 fathoms, Professor Bailey. Atlantic
soundings, Mr. Roper. ;

Were it not that I possess specimens of this species from
Professor Bailey himself, I could scarcely have recognised it
from the brief notice he has given of it in ‘Silliman’s Jour-
nal,’ and still less from the figure which accompanies it. The
fact is, the characters which he attributes to it are now
shared in common with other species, and we have to look
for other distinctive marks. In some points, the species is
allied to A. Roperiana, being apparently quite circular, and
having the base of the segments square, or nearly so. An
additional resemblance is also found in the median lines,
which scarcely cover the central point, being arched at the
top, then contracted, and lastly expanded, though not to the
same extent as in the species just mentioned. Professor
Bailey’s figure represents the base of the segments as
decidedly curved as in A. Marylandica, but they are more
nearly square, and in some valves quite so. The umbilical
lines radiate from the upper half of the median lines, and
are sometimes branched. There is an angular bend, nearer
to the outer extremity than in any other species, and at each
angle the minute spime-like process indicates probably the
base of a ramulus. This may also be seen at the base of the
median lines. The areolation is conspicuous. The number
of rays, according, to Bailey, varies from seven to thirteen, or
more; in my specimens they are from ten to twelve. The
frustule, when perfect, is very convex.

16. Asterolampra Roperiana, n. sp., Grev.—Valve cir-

cular; hyaline area centrical ; areolated segments square at

the base, almost equal; rays seven; median lines passing
round the central point in a semicircle, then contracted
below, and lastly widely expanded. Diameter -0028” to
0066". (Fig. 14.)

Hab.—\ndian Ocean, in soundings made by Captain
Pullen, in 2200 fathoms.

[t is unnecessary to repeat the remarks which I have

already made on this most interesting diatom, as constituting

GRrEVILLE, on Asterolampra. 121

a link between the last and the present section. In fact, had
the two median lines united af the central point instead of
being carried just round it, it would have been included in
the last section. In other words, it would have been an
« Asteromphalus,’ instead of a “ Spatangidium.”’ The six
perfect rays are broad, and equal to the margin, like those of
De Brébisson’s Spatangidium heptactis. The umbilical lines
have an angular bend, which is so obscurely developed as to
be liable to be overlooked ; but the indication of the bend in
the median lines, towards the margin of the hyaline area, is
more conspicuous. When carefully looked for, however,
they will be perceived without difficulty. I have even suc-
ceeded in tracing in two specimens very slender ramuli,
passing from the angles of the bend to the angles at the base
of the segments, exactly as in Spatangidium heptactis ;
but to do this requires the most careful adjustment possible,
and such a management of illumination as to throw the um-
bilical lines, and ramuli, and edges of the ray cavities into a
light definition. The umbilical lines, including the median
ones, are robust, and the areolation rather large. The valves
seem very constant to the characters given, as I have tested
by an examination of above a dozen specimens. In one only
did the median lines vary, in becoming widely sub-parallel,
instead of diverging. Perfect examples are very rare. The
individual figured is the most perfect, but by no means the
largest in my cabinet.

17. Asterolampra Shadboltiana, n. sp., Grev.—Areolated
segments square at the base; umbilical lines radiating from
the arch of the pyriform median lines, with the angular
bend about the middle; rays seven, terminating consider-
ably within the margin. Diameter 0031". (Fig. 19.)

Hab.—Indian Ocean, in soundings obtained by Captain
Pullen, in 2200 fathoms.

Mr. Roper very kindly sent both his accurate drawing and
the slide containing the valve of this interesting species for
my inspection; and I have since been so fortunate as to dis-
cover a second example for myself, so minutely similar that
the engraved illustration might have been taken from either
specimen. It seems to be a really well-marked diatom. Its
nearest ally is perhaps 4. Brookei, from which it is separated
by the very different median lines, and by the angular bend
being more in the middle of the umbilical iines. If the
termination of the rays so much within the margin of the
valve, and singularly short median ray, prove permanent
characters, they will serve still farther to distinguish the
present species. I suspect, also, that, as in A. Roperiana,

122 GREVILLE, on Asterolampra.
A. heptactis, and A. Arachne, the number of rays may be more
constant than is generally the case in the group. The
areolation is rather large.

18. Asterolampra heptactis —Segments square at the base ;
rays seven, six of them broad, linear, subarcuate, the median
one in a broad shallow groove; umbilical lines with a
ramulus proceeding from each angle of the bend ; areolation
large. Diameter ‘0018” to -0070".

Spatangidium heptactis, De Bréb., Bull. Soc., Linn. de Normand.,
vol. iii, pl. 3, fig. 2. si

Spatangidium Ralfsianum, Norm., Grev. Mic. Journ., vol. vii, p. 161,
pl. 7., figs. 7, &.

Hab.—Peruvian Guano, De Brébisson. Californian Guano,
R. K. G. Atlantic soundings, Mr. Roper.

The extraordinary discrepancy between the figure, with part
of the character in De Brébisson’s paper above quoted, and
the numerous specimens of the diatom itself, which I had
examined, led me formerly to regard Mr. Norman’s Spatangi-
dium Ralfsianum as a distinct species. The broadly ovate
outline of the valve delineated by De Brébisson, and the state-
ment in his specific character, that the median ray was the
longest, were opposed to my own experience; for I had ever
found the valve broadest in the transverse direction, and the
two lower lateral rays the longest. I still consider that my
figure 8, above quoted, is typical of the species, as it agrees
with the vast majority of specimens. While, however, I was
supported in my view by some diatomists, others were
against me, and I am at length satisfied that we had the
same organism in view. Among some careful drawings of
his own making, which Mr. Roper kindly permitted me to
consult, are two of this species, and in one of them there is a
slight approach towards a broadly ovate outline, and the
median ray is the longest; but this is decidedly an exceptional
case, unless, indeed, the Peruvian frustules differ in contour
from those of California. There is a curious feature in this
species which I did not formerly notice: the very slender
ramuli which proceed from each angle of the bend in the
umbilical lines terminate at the angles of the areolated
segments, in a line with the margin of the broad rays; the
consequence of which is, the two small spaces enclosed by
these ramuli, at the base of each of the segments although
they form a part of the hyaline area, are excluded from the
basal portion of the ray. It may be observed also, that as in
this fine species, as well as in A. Roperiana, the angular bend
is distinctly connected with a system of ramification, it may

GREVILLE, on Asterolampra. 123

be inferred with some degree of confidence, that it is an
important character when met with in other species. Little
spine-like processes are seen to project from the angles in
several allied forms, and may be the basis of similar ramuli.
In the diatom under consideration, the base of each ramulus
is conspicuous, but it appears at first sight to stop abruptly,
and it requires very careful adjustment to trace the fine con-
tinuation to the angle of the segments. In other species,
while the spine- like base is sufficiently obvious, the very
delicate continuation may escape observation altogether. The
colour of the valve is very pale yellow ; the areolation larger
than in any other member of the group.
_ 19. Asterolampra Arachne.—Valve broadly ovate ; hyaline
area very small and eccentrical ; areolated segments curved
at the base, the upper one very widely, the lateral ones
sharply ; umbilical lines two, lateral; median lines dilated
upwards ; rays five, the two superior ones curved upwards,
widely apart. Diameter about ‘0021’.
ries ie nag De Bréb., Bull. Soc. Linn. de Normand., vol. iii,
Astron malleus, Wall., Trans. Mic. Soc., vol. viii, p. 47, pl. 2,

Hab.—Peruvian Guano, De Brébisson. In Salpe, Indian
Ocean, Dr. Wallich. Indian Ocean, in soundings at 2200
fathoms, made by Captain Pullen.

It would be fortunate for the student if diatoms were in
general as faithful to their characters as this remarkable
species. It is one of the few belonging to the present group,
of which it may be said that the number of rays is really
constant. Their disposition is also very peculiar. The hya-
line area is so small as scarcely to be perceived at first sight,
being composed merely of the very short suddenly dilated
bases of the four perfect rays and the space enclosed within
the short median lines. The rays are attached to the sides of
the median lines, nearly the whole of which they occupy.
The upper pair turn their backs, as it were, on the lower pair,
curving outwards and upwards, and bear much the same rela-
tion to the median lines as the horns of an ox do to the frontal
bone. The lower pair of rays are straight, and point laterally
downwards, forming a group of three with the median ray.
The median lines also exhibit a character peculiar, I believe,
to this species, in not being united at the top; they do not
even incline towards each other, but stop abruptly, leaving
the intervening space in juxtaposition with the base of the
upper areolated segment. Another anomaly occurs in this
part of the valve, in the segment just mentioned being un-
supported by an umbilical line. The areolation is large ; and

124 GreviLLE, on Asterolampra.

the colour of the valve, even when mounted in balsam,
brownish yellow. Two specimens only have occurred to me,
in the Indian Ocean soundings. “ee

20. Asterolampra Sarcophagus.—< Valve oblong, with a
slight constriction near each extremity ; basal ray plane, and
continuous with one of the true rays; sutures plane; cellules
very large. Length 0018"; breadth -0009".”

Asteromphalus Sarcophagus, Wall., Trans. Mic. Soc., vol. viii, p. 47,
pl. 2, fig. 12.

Hab.—Indian Ocean, from Salpe, Dr. Wallich.

As I have not had an opportunity of examining this very
curious diatom, I give the specific character in Dr. Wallich’s
own words. The form of the valve is so extreme a deviation —
from the otherwise more or less orbicular shape of the entire
series, that an impression almost forces itself upon the mind
that it is simply a malformation. Dr. Wallich does not men-
tion how many individuals have come under his notice, but
he has probably seen a sufficient number to satisfy him that
its eccentricity of outline is permanent. It is most nearly
related to A. Arachne; for if we remove the terminal ray
(which in many species may be either present or absent), the
five remaining rays would occupy the relative position which
they hold in that species, as well as the same direction; one
pair of perfect rays poimting upwards, the other pair down-
wards. In both species also the areolation is large.

Among several frustules of which I have only seen single
specimens, and whose position is doubtful, is a minute and
beautiful valve, of which I give a figure (fig. 20). It is
allied to A. Hiltoniana and A. flabellata, but cannot be
satisfactorily referred to either. The lowest pair of umbilical
lines are curved downwards, as in the former species. The
median lines are parallel, and continued to the edge of the —
hyaline area, or, in other words, to the base of the median
segments, in a decidedly square manner. The valve, at a first
glance, is most conspicuous for the large size of the hyaline
area and the consequently rapidly attenuated rays; but this
may prove to be a worthless distinction. It is only 0018” m
diameter. I shall not attempt a formal character, but it may
bear, for the sake of convenience, the provisional name of A. —
stellata. It occurs in the Jndian Ocean soundings. |

Asteromphalus centraster, of Dr. C. Johnston, from Elide
Guano (‘ Mic. Journ.,’ vol. viii, p. 12, Pl. I, fig. 10). I can-
not speak of with any certainty. The rays, in being con-
tinued like distinct bars, or the ribs of an umbrella, from the
central point to the margin, are unlike those of every known
species of the group. There is evidently no true median ray.

ALuLMAN, on Carduella cyathiformis. 125

On THE Srructrure oF CARDUELLA CYATHIFORMIS. A con-

tribution to our knowledge of the LuceRNartap™. By
Prof. Attman, F.R.S., &c. &e.

In the month of August last, during a short sojourn
among the Orkney Isles, my attention was directed by Mr.
Gilchrist of Stromness, to a little Lucernarian zoophyte,
which he had discovered attached to stones near low-water-
mark, in the neighbourhood of that town.

The little animal proves to be identical with the Lucernaria
cyathiformis of Sars; but its characters are such as to con-
vince me that it must be separated from the true Lucernarie,
and assumed as the type of a distinct genus in the family
of the Lucernariade. That I am justified in this view, will, I
think, appear from the following description :—

Fam., Liucernariav%.

Gen., CARDUELLA, mihi.

F aye" diminutive noun from carduus, a thistle, in allusion to its
orm.

Gen. Char.—Body stalked; tentacles capitate, not tufted,
springing from within the margin of a circular disc in a
single series.

C. cyathiformis, Sars.—Body urceolate; peduncle dilated
at its base into a dise for attachment ; tentacular circle in-
terrupted at about eight nearly regular intervals, by the non-
development of certain tentacles.

_ Synonym.—Lwucernaria cyathiformis, Sars, in Fauna lit. Norveg.; John-
ston, Brit. Zooph., 2d Ed., p. 475, fig. 86.

Hab.—On stones near low-water-mark.

Localities—Coast_ of Norway, Sars; Island of Arran,
Scotland, Rev. D. Landsborough ; Stromness, Orkney, Mr.
Gilchrist and G. I. A.

Carduella cyathiformis is about half an inch in height.
The body is hemispherical posteriorly, where it is seated on
the summit of the peduncle; it then contracts behind the
tentacular circle, and then again expands into a wide circular
disc, whose margin is not produced into rays, as in the
true Lucernarie, and which has the mouth in its centre.
The tentacles, slightly tapering from the base, and each
ending in a spherical capitulum, do not, as in Lucernaria,
spring from the edge of the cup, but from a circle situated at
some distance within it, and in the fully expanded state
of the animal extend about as much again beyond it.

The tentacular circle is interrupted at four nearly regular

126 Aptian, on Carduella cyathiformis.

intervals; but all the tentacles are situated in a single circle,
and never form tufted groups as in Lucernaria.

Each of the four interruptions in the continuity of the
circle of tentacles is caused by.a single tentacle having that
at each side of it arrested in its development, so as to
present under the lens the appearance of little conical papille
(Pl. V, fig. 8, m), while the developed tentacle, situated
between the two arrested ones, is invariably bent over the
edge of the cup in the expanded state of the animal (figs. 1, 3,)

and thus renders the interruptions in the circle still more —

obvious. Not unfrequently, other interruptions are observed
in the tentacular circle, caused by a similar abortion of one
or more tentacles; but these are less regular in position, amd

less constant in occurrence, than those just described. “4d

In the centre of the oral disc is a prominent four-lobed
mouth, and the extremities of the four generative bands may
be seen projecting from below each angle of the mouth,
and distinctly visible through the disc, by the greater depth
of their colour.

The peduncle is distinctly annulated both in the extended
and contracted state, and terminates below in a little disc-
like dilatation, by which the animal fastens itself to the
rock ; but I cannot find that it has the power of detaching
itself when it has once become fixed.

The colour of C. cyathiformis is a brownish-red, with the
stomach and generative bands conspicuous, by their deeper
colour, through the semi-transparent walls of the body ;
while, just behind the bases of the tentacles, the body is
marked by a deep-brown circle ; and four paler lines, sepa-
rated from one another by equal intervals, extend backwards
from this circle to the summit of the peduncle.

It was a very frequent thing to meet with two individuals

growing from a single basal disc; but this I believe to be a —

case of simple fusion from contiguity, and not an example of —

gemmation or other form of zooidal multiplication.

Carduella cyathiformis is one of the most elegant members —

of our littoral fauna, and rarely will the wanderer along the
shore at low tides have his search more amply rewarded than
by the capture of this charming little zoophyte.

Anatomy.—A transverse section (fig. 4) made about the

middle of the body, or a longitudinal section (fig. 3) passing

through the axis, shows an outer bell or umbrella (a), tra- —

versed in its axis by a quadrilateral, elongated stomach (6). In

the walls of this stomach, along each of its four angles, runs a —

double lobulated band (c), which projects into the cavity of
the stomach, and is the seat of the ova or spermatozoa.

ALLMAN, on Carduella cyathiformis. 127

From the outer side of the walls of the stomach there extend
to the umbrella eight membranous vertical lamellze (figs. 3,
4,d). These are so arranged, that from each of the angles along
which one of the four generative bands runs two lamelle are
given off, and thence diverging at a wide angle, are attached
by their outer edges to the inner surface of the umbrella,
along a longitudinal ridge (e), which also gives attachment to
one of the lamellz of the neighbouring pair. There are thus
four of these ridges, each giving attachment to two lamelle,
and situated alternately with the four angles of the
stomach to which the opposite edges of the lamelle are
attached.

The result of this arrangement is the formation of eight
spaces, four of which (/) are situated externally, while the
other four (g) alternate with these and lie internally.

The four outer spaces are closed above, and their roof thus
forms the oral disc (h) of the animal; while the four inner spaces
are open, and allow a needle to be passed down along the
side of the stomach the whole way as far as the peduncle.

Each of the four ridges, along which the vertical laminze
are attached to the inner edge of the umbrella, seems to be
traversed through its entire length by a canal. They are
visible in the living animal through the walls of the umbrella,
where they appear as four pale-coloured lines, extending sym-
metrically from the summit of the peduncle as far as the
tentacular circle.

Running along the bases of the tentacles, so as to form a
continuous circle at some distance within the margin of the
disc, is a deep reddish-brown line (), which I have no hesi-
tation in viewing as a circular canal, into which the tubular
_ tentacles all open.

Upon the inner surface of the stomach are eight longitu-
-dinal rows of tubular appendages (k), two rows being situated
in each of the four intervals between the generative bands.

They are finely ciliated on their surface, and have their walls
loaded with large thread-cells.

I have not satisfactorily made out the structure of the
peduncle; but it seems to present the principal parts demon-
‘Sstrable in the body, namely, the umbrella, stomach, and
generative bands, compressed into a smaller space and less
distinguishable from one another.

Round the margin of the umbrella runs a band of circular
muscular fibres (/), which performs the office of a sphincter
in closing the mouth of the umbrella during the contracted
state of the animal; while other fibres radiate in the oral
disc, where they may be seen converging from the circular

VOL, VIII. 0

128 Atuman, on Carduella cyathiformis.
canal at the base of the tentacles towards the central

stomach. k ; ;
In the ova (fig. 5), the germinal vesicle and germinal spot

are distinct ; and the spermatozoa (fig. 6) present a charac- |
teristic hydrozoal form, consisting of conical corpuscles, with
the caudal filament attached to the broad end of the come.
Homologies.—As to the true import of the structure now F
described, it will be easily seen that we have in it a genuine ©
hydrozoal type, notwithstanding a certain superficial resem~ —
blance to the structure of the Actinozoa. The point which
at first sight seems to remove it most widely from the
Hydrozoa, and approximate it to the Actinozoa, will be found —
in the presence of the vertical lamellee which connect the —
stomach with the outer wall of the animal. A little atten- —
tion, however, will show that these must on no account be ©
confounded with the radiating lamelle of an Actinia, from
which they differ entirely in their arrangement and relations. —
The axile stomach of Carduella is exactly the manubrium
of a Medusa, while the external body-walls correspond to
the umbrella; and if I am correct in my interpretation of
the appearances which lead me to believe im the existence of -
longitudinal and circular canals, we have in them the exact
representatives of the radiating and circular canals of the
gastro-vascular system of a Medusa. “
As to the homology of the oral dise, I cannot help seeing
in this muscular membrane the representative of the muscular
velum of a gymnophthalmic Medusa, which, instead of being,
as in the Medusa, free towards the axis of the animal, is here
united to the stomach, while it is at the same time extended
and so folded into plaits, as to form by the union of these
plaits alternately to the stomach within, and to the umbrella
without, the four pairs of vertical lamelle; and although
what we know of the development of the velum in the Medusa
can scarcely be said to give any direct support to this view,
it certainly is not inconsistent with it. yo
It will now be seen that it is with the gymnophthalmic
rather than with the steganophthalmic Medusa, that the
affinities of Carduella are to be sought. We have, indeed
only to conceive of a gymnophthalmic Medusa, with its
stomach (manubrium) united to the umbrella along four
equidistant longitudinal lines through the medium of a pecu-
liarly plaited velum, in order to convert it, so far as regards
the most important points of its structure, into a Carduella.

129

On the Devetorment and Structure of the DiavoM-vALveE.
By G. C. Waxticn, M.D., F.L.S.

_ Iva paper recently published in ‘The Annals and Maga-
zine of Natural History,’ I endeavoured to show the unfit-
ness of the valves of the Diatomacez as standard tests for
_Inicroscopic lenses, and based my objections to their
employment on the variable character of the markings in
different individuals of the same species, in the same species
under varying conditions of development, and in the same
specimen under different methods of examination. In deal-
ing with this subject, I purposely selected Pleurosigma angu-
latum and P. balticum, the forms most frequently referred to,
without assuming, for a moment, that the markings of these,
or any other diatoms, are of sufficient importance, in a bio-
logical point of view, to entitle them to interest; and solely
because it became imperative on me, whilst condemning tests
hitherto relied on, to prove that some of those most constantly
im use, and in the delineation and description of which the
greatest pains has been taken by writers, exhibit characters
irreconcilable with the structure usually assigned to them.
In the following observations, I shall principally endeavour
to prove that growth does not take place in the diatom valve,
after its primary development; and that the variation observ-
able in the size and markings of different individuals of the
Same species is not only consistent with this view, but
naturally follows from it.
The mere discussion as to whether the surface of a valve
exhibits this or that kind of markings, so long as no higher
‘purpose is in view than the production of certain appearances
under the microscope, and the claim of superiority for the
‘instrument whereby the most Protean aspects are engendered,
must always remain barren of scientific results. For we are
bound not only to see, but to comprehend the relation of one
portion of minute structure to another, before we are in a
position to draw serviceable inferences from it. It is well
understood, by all who have had experience in microscopic
“manipulation, that great caution is necessary in pronouncing
“upon the precise structure of an object; and that, under
‘imperfect adjustments, either as regards the object or the
instrument, an indefinite amount of variation may be made
apparent. This is especially the case under the employment
of the higher powers. For, although the definition of the
entire series of objectives, manufactured by our leading
“opticians, may be said to be equally perfect, a variety of

130 Waxuicn, on the Diatom-valve.

conditions are essential to secure accuracy of observation, and
these can only be fulfilled under the exercise of the strictest
vigilance and judgment. é

But whilst the minute structure of the diatom-valve may
be deemed by some persons unworthy of the labour that has
been bestowed upon it, it is indisputable that the correct ex-
position of that structure involves a question, quite as mmpor-
tant, perhaps, as any we have to encounter in the whole course
of vegetable physiology ; and however cynically some of our
intellectual eagles may affect to treat the subject, they may
rest assured that no little honour awaits the observer who
shall place the laws by which it is governed in an intelligible
light.

“Why, let me ask, does one organism present peculiarities
in the arrangement of its cell-wall which do not occur in
another immediately allied to it? Why do we find organisms
belonging to the same group, formed on the same general
plan, surrounded by the same influences, and deriving
nourishment from the same medium, vary so remarkably in
the disposition of one of their elements, in which we should
least expect to meet with variability? Thus, amongst the

Diatomacez, why do we observe such differences between the —

arrangement of the siliceous particles in Triceratium and
Campylodiscus, Campylodiscus and Pleurosigma,or Pleurosigma
and Pinnularia, and so on with the remaining genera? As
nothing in nature is, or indeed can be, fortuitous, some law
must operate in bringing about these differences. Although
as yet ignorant of the nature of that law, there is no reason
whatever why we should remain so. Day after day brings
forth fresh facts, in elucidation of the complicated scheme of

tea

creation; and no one can tell, therefore, how great a length ~
of the chain of knowledge may be consolidated, by the addi- —

tion of a link snatched from objects holding no higher place
in the scale than the unpretending diatom.
Other more startling discoveries have been effected, and -

ioe

have earned for the discoverers ereater éclat; but it is_
doubtful whether any have surpassed in physiological value

Schwann and Schleiden’s enunciation of the theory of cell-
formation. On this basis the study of the entire organic

world may be said to rest. It is the groundwork of our

acquaintance with the structure of every living thing, from
the lowest protophyte up to man. But there is a link, yet

tte ell

beyond that point, which requires to be filled up and riveted. |
| allude to the law that presides over the development of the |

cell-wall; and this, I coneeive, can hardly be studied more
advantageously than amongst the Diatomaceze, the indestruct-_

.

Watticu, on the Diatom-valve. 131

ible nature of which, coupled with their extreme trans-
parency and the already understood chemical relations of
their siliceous element, renders them so well fitted for the
inquiry.

It is admitted on all sides that the rules by which species
have heretofore been established demand material modifica-
tion. Amongst the Diatomacez, a line, a dot, a minute spine,
or a variation in size or outline, amounting, relatively speak-
ing, to nothing more than we see occurring amongst indi-
viduals of the same species of every animal and plant in
nature, has been accepted, by some observers as of sufficient
moment to constitute a specific character. Almost every
microscopist has fallen more or less into this error. But it is
by no means anerror confined to one class of observers ; for
entomologists, botanists, and conchologists are in exactly
the same predicament. So that our knowledge of the minute
Fauna of the globe, after all, is but in the same state as that
of other branches of natural history, making due allowance
for the multiplied difficulties by which microscopic investi-
gation is specially beset.

Now, in the case of the Diatomacez, the leading generic
characters are taken from the configuration of the siliceous
valve. The sooner, therefore, that we gain such an insight
into the law which regulates the deposit of the silex, as shall
enable us to judge how far the differences of configuration
may be dependent on chemical or molecular forces, and how
far on the inherent property of the organisms themselves, the
sooner shall we have it in our power to establish a natural
classification, and to simplify, by rendering determinate, the
methods of investigation.

We have before us the phenomenon of a mineral, elimi-
nated or secreted by what we are pleased to denominate a
simple cell, in a state of the utmost purity, and assuming
definite forms, which may be said to hold an intermediate
position between crystallization and simple molecular aggre-
gation. We know the fact, but as yet we know absolutely
nothing of the causes producing it. Surely then the investi-
gation of such a problem is worthy of the best efforts of the
microscopist ; and from this point of view, even the “ dot’
may exercise a world of significance.

But whilst it is necessary that we should possess a clear
idea of the structure of the siliceous wall of the diatom, it is
by no means essential that we should have at our finger ends
the precise nature of the surface in the more minute and
subtle forms, or indeed in any save those that are typical
and most easily revealed. If analogy means anything at all,

132 Waxticu, on the Diatom-valve.

it surely authorises us to accept as most closely allied in
structure those forms which, by universal consent, have been
arranged side by side. We are sure to meet with stronger
and more reliable analogies amongst the several species of
the same genus, than amongst those of distinct genera. The
statement of the one fact is but a statement of the other.
And, for this reason, it is obvious that, in microscopic inves-—
tigation, we are warranted in resorting to the most strongly
marked and most readily observed species of a genus, when
we attempt to draw general conclusions regarding its orga-
nization.

I allude just now more particularly to the genus Pleuro-
sigma, of which a species, P. angulatum, has been handed
down from writer to writer, both in Great Britain and abroad,
as the one, par excellence, presenting us with typical struc-
ture. That it does exhibit structure identical in every essen-
tial particular with that observable in the rest of the species
of that genus is undeniable. But, although by no means a
difficult object for a quarter-inch lens of good construction,
the markings on its valves are much more minute and
delicate than is the case with other species; and accordingly
the risk of misinterpretation, when it is viewed under higher
powers, is necessarily augmented. I shall therefore select
two other forms as typical of the rhomboidal and quadran-
gular structure, in which the characters can be made palpable
both more easily and more distinctly.

Before entering, however, on a description of the structure
in Pleurosigma, I would briefly point out the manner in
which it appears to me the Diatomaceous frustule is
developed ; and to what extent the variations of conditions, to
which it is subject during such development, seem likely to
affect the siliceous deposit.

Inthe first place I would mention, that there is no evidence
of growth proceeding continuously in the diatom-valve—if
by growth be meant the increase and extension of the entire
structure in every direction, as occurs in the higher orders of
the vegetable kingdom. Some writers have endeavoured to
account for the variable character of the striation in certain
species, by asserting that, although the number of striz in a
minute fractional part of an inch is subject to considerable
variation, the total number of strize on the valves of all indi-
viduals of the same species or varieties is not liable to the
ike amount of deviation. In other words, they consider
that the siliceous valve is capable of continuous growth ; and
that, whilst no fresh strize are added to the valve, the distane
between the several strize may be augmented. Others again

Wattuicn, on the Diatom-valve. 133

modify this view by supposing that an addition may take
place to the actual number of the striz.

Now, whilst I fully admit the correctness of the first of
these premises,—namely, that whilst the total number of
strize on a valve is nearly uniform in all the individuals of a
given species orvariety, the number of strize upon the fractional
part of the valve admits of very great variation,—I dissent
entirely from the opinion that the number of the striz in a
fractional part of a valve is capable of modification, either
by the extension of the valve through growth, the total
number of the striz remaining the same, or by additional
striz being produced within the limits already attained.

The fact is, that the variation in the size of the valve and
the number of its striz proceeds, pari passu, during the
progress of division, but not subsequently. Growth may
take place to the extent of fresh siliceous matter being
secreted along the margins of the valve, its depth being
thereby somewhat augmented; but it is highly probable, for
reasons which shall immediately be adduced, that the con-
necting zone, by which the young valve is protected during
its secretion and consolidation, determines the limit of the
dimensions to be attained by it; and although the young
valve may still have to undergo a certain degree of conso-
lidation, the whole of the characters, as we observe them
under the microscope, are indelibly and unalterably impressed
upon it, either before or almost immediately after its libe-
ration. In like manner, the two rings of the connecting
zone grow lengthwise by secretion of fresh siliceous matter at
one of their margins only—as was shown by me in a former
communication to the ‘Microscopical Journal’ (vol. vi, p.
224)—and they are thus enabled to slide out, one from the
other, telescope fashion, and to accommodate themselves to
the increase of their contents during division. The last
feature is strikingly manifest in such genera as Biddulphia,
Amphitetras, Isthmia, Grammatophora, and others.

1 believe I am quite correct in stating that it very rarely,
if ever, happens that an imperfectly developed—that is, an
immature—valve is found associated with one of the parent
valves from which it was derived, after the separation of the
parent connecting zone; whereas we constantly meet with
such a combination prior to that event. In the next place,
whensoever we find, through the evidence of the still per-
sistent connecting zone, that a young valve has but recently
been perfected, its structure presents no peculiarity whereby
it can be pronounced to differ from the parent valve with
which it is associated. We frequently meet with frustules,
furnishing incontestable evidence of recent division having

134 Waxuicn, on the Diatom-valve.

<en place, as just stated, equalling in dimensions the largest
—_ aE 3 species to which they belong. And, lastly,
we never meet with such differences in size and markings as
would, of necessity, result, did growth continue in the
terminal parent valves of an elongated filamentous species ;
whilst the central or most recently produced valves exhibit
only the size and markings attained by the parent valve at
the period at which the first occurrence of division intervened.

A further and most remarkable confirmation of the view,
that growth does not take place in the valve after its libera-
tion from the parent connecting zone, is, I submit, derived
from an abnormal form of Triceratium favus, a figure and
description of which are given by Mr. Brightwell, im the
‘ Quarterly Journal of Microscopical Science,’ vol. i, p. 246. In
this specimen, an oblong portion, equal in extent to about one
third of the entire valvular surface, is cleft out, as it were,
from one of the angles. It is evident that, from whatsoever
cause this configuration occurred, that cause must have taken
effect whilst the valve was still in the plastic condition, to
which reference has been made; for the cleft margin is
fringed by a regular series of quadrangular cellules, such as
we frequently observe along the inflected edge of the valve in
the species under notice. As the specimen must have been
subject to the action of acid or heat, before its intimate struc-
ture could have been examined and figured, it is equally
evident that the valve had attained its mature and perfected
condition. It should be borne in mind that the valve is of
normal outline and configuration on the remaining surface.
There is no projection from the sides or angles, indicating
that the object to which the abnormal development was due
had taken effect after the complete valve had been deposited ;
but, on the contrary, it is clear that such object must have
presented an obstacle to the complete development of the
valve whilst it was retained within its parent connecting
zone. From the shape of the emarginate portion, it would
appear to have been produced by growth taking place around
some substance, such as a calcareous or siliceous spicule.
From its not having been retained in situ, we may infer—
either that, being siliceous, it had broken its way out at the
deficient angle ; or, being calcareous, that it had been dissolved
during the operation of cleaning by acid. It is hardly possible
to conceive that an object could pierce the already perfected
and consolidated diatom-valve. But, supposing that possible,
it is certain that fracture must have resulted, or that an
extent of valvular surface must have been displaced of equal
bulk to the emarginate space.

It may be asked, then, to what cause are we to attribute the

Watticu, on the Diatom-valve. 135

variation in dimensions that occurs so frequently? If not
to growth, in the ordinary sense, to what other cause? It is
attributable, in the first place, to imcreased or diminished
supply of nutrition to which the species happens to be subject;
acting by the production of differences between the parent
and the young valve, wholly inappreciable to our vision, not-
withstanding all our appearances, but yet quite capable of
effecting the variation in question, through the intervention
of a multitude of individuals. In strict truth, no two valves
of the same frustule can be of the same size ; for the new
valves, being formed within the connecting zones of the parent
frustule, must be smaller than these. In answer to this it
may be urged that, in the usual course of growth, they reach
the dimensions of the parent valve. But unless we are pre-
pared to admit that the latter obligingly cease growing for a
time, to permit of the requisite uniformity in size being
attained, it will be seen that this objection is invalid. The
difference in the two valves arising from the last-mentioned
cause, however infinitessimal it may appear in the case of the
individual, becomes, nevertheless, all-powerful when operating
through vast successions of individuals ; and is, therefore, of
itself sufficient to account for the variations we witness.

The main source of difference, however, in the size of the
valves of any given species is derived from the peculiar
idiosynerasy of the sporangial frustule. The large dimensions
that frustule attains in many cases is well known. And,
although the precise history of the produce of the sporangial
cell still remains doubtful, there is, I believe, quite sufficient
evidence forthcoming to show that the prevailing opinion, as
to the great variation in dimensions of the new brood, is quite
correct. If we bear in mind the vicissitudes of climate and
locality to which the sporangial cell may, under certain cir-
cumstances, be subjected, we can readily understand, more-
over, how increased or diminished sources of nutritive matter,
dependent on those vicissitudes, may affect the produce of
that cell towards either extreme.

In Jsthmia, a genus offering remarkable facilities for the
detection of differences between the size of the old and the
new valves of the frustules, after careful and oft-repeated
examination, I have been quite unable to detect any differ-
ences independent of the causes associated with the connecting
zone to which reference has already been made. In this genus
and in Biddulphia, the overlapping of the two rings of the
connecting zones is more strikingly manifest, perhaps, than
in any other forms, and the entire frustules are often of such
magnitude as to enable us clearly to distinguish the contrast,

136 Watticn, on the Diatom-valve.

in internal area, of the two valves, arising from this source.
In Isthmia, we also sometimes observe great variation as to
length and breadth of frustules growing upon the same object.
But it will be found that these marked differences do not
occur in the same filament, but on separate ones; and that
the primary frustule, or rather that valve of it by which
epiphytic adhesion was first secured, frequently does not
exceed in size the smallest of any of the other neighbourmg
terminal frustules. ;

After similarly extended observation of the compressed
filamentous genera, I have never found any ground to alter
my views respecting the determinate period durmg which
the siliceous value may be said to increase; and, as an
example in point, and one which, for several reasons, is
amongst those best fitted to test its correctness, I would
mention having carefully measured, by means of Ross’s screw
micrometer, frustules of the three species of Rhabdonema,
at intervals, in filaments numbering as many as a hundred
individuals, without the discovery of any difference in the
length of the valves of sufficient magnitude to be referable to
any other cause. When it is recollected that, in this genus, the
frustules are annulate, and the entire structure would appear
specially liable to variation in size, from the repetitive process
alternating, as it were, with the extension of the frustule
through the deposition of the annulate portions, it will be
admitted that a more satisfactory test genus could not have
been selected. I would add, for the guidance of those who
may desire to repeat these measurements, that a source of
fallacy exists which must be carefully guarded against;
namely, the change of apparent size depending on the struc-
ture under examination not being placed perfectly fiat upon
the surface of the slide. A very little management will,
however, suffice to ensure the proper position.

As regards the cell-contents, and the gelatinous envelope
by which the whole of the Diatomacez are, in a greater or —
lesser degree, surrounded, growth goes on, in all probability, —
indefinitely. The present observations must be understood —

to apply, exclusively, to the siliceous valve of these organisms;

and are offered with a view to prove that the specific markings —
of any given form are definitely impressed upon it, either at —
the period when division is completed, or almost immediately —
afterwards ; and that whatever may be the normal shape of —
these markings—that is to say, their primary form in the ©
young valve—being disposed in a determinate order with —
relation to each other, and to the boundaries of the frustule, —
their ultimate configuration is determined, in a principal —

Watticu, on the Diatom-valve. 137

degree, by the form of the frustule, and by the direction in
which that form exercises a constrictive force, whilst the
siliceous material of its valves is still in a plastic condition.

If we admit this proposition, we cannot fail to comprehend
how materially the nature of valvular markings may be modi-
fied by any variation in the condition to which the parent
frustule may be exposed during the period of division; and
we at once recognise the futility of drawing specific characters
from the mere numerical estimate of strie within certain
limits, or, indeed, from any structural peculiarities apart
from such as are constant.

Much of the confusion that exists with regards to the
““striation” or “lineation” of the Diatomacez arises, I con-
ceive, from the vague manner in which these terms are
employed to indicate different portions of the valvular struc-
ture. Thus, in Pleurosigma, the terms are used, by some
writers, to indicate the lines presented to the eye ‘by the
coalescence of the several series of intra-linear spaces ; whilst,
by others, they are intended to denote the lines formed by
the boundaries of those spaces. This last is certainly the
correct view; and it is borne out by the circumstance that
the outline and peculiarities of the intra-linear spaces are
determined, as shall presently be shown, by the inherent
order of the lineation, and not the lineation by the inherent
‘development of the spaces.

In the ‘Synopsis of British Diatomacer, the valve of
Pleurosigma is stated as being “ striated; stric resolvable
into dots, which are frequently hexagonal.” Other writers
are also in the habit of alluding to “striz composed of
dots.” From this definition it is impossible to gather
whether the lines we observe crossing each other at certain
angles are indicated, or the spaces bounded by the intersec-
tions of those lines. In reckoning the number of lines in
the one-thousandth part of an inch, the measurements are
evidently derived from the first of these points; whereas it
is undeniable that the so-called “dots” occupy the intra-
linear spaces. The number of “ dots,’ and the number of
“strie,” therefore, can never tally; and, for a similar
reason, it involves a contradiction to say that the “ striz are
resolvable into dots.” It remains still a point of dispute
whether the intra-linear spaces are depressions or eleva-
tions. It is not improbable that they are elevations in some
species, and depressions in others. Fortunately, however,
the solution of the question is a matter of no great moment
for purposes of classification; and it becomes of still less
‘importance when we bear in mind, that as a valve happens

138 Watuicu, on the Diatom-valve.

to be viewed in one or other of its aspects, so must the
appearance of elevations or depressions vary. At present, it
:s only in some of the more boldly-marked species that we
can decidedly pronounce which surface of a valve is directed
towards the observer. On this account I have adopted the
use of the somewhat vague term, “ intra-linear” spaces, to
designate those portions in which the appearances of eleva-
tions or depressions occur, leaving the peculiar nature of
such spaces to be dealt with in each separate case.

If we examine the valve of any of the most boldly-
marked species belonging to the Naviculoid group of dia-
toms, as, for example, Pinnularia distans, alpina, or lata, we
meet with what I conceive to be the simplest form of linea-
tion, namely, a series of narrow, elongated, depressed
“coste,’—as they are very inappropriately termed,—ar-
ranged in transverse order on the surface of the valve, and
rendered remarkably distinct by their superior degree of
translucence, and the contrast they present in refractive
power with the adjacent parts. Neither the depressed
“‘coste ”’ nor the intra-costal spaces exhibit any trace of
secondary markings. In proof of the ‘“coste” being
depressions, it may be mentioned that, whilst the median
line and nodule and the entire margin of the valves exhibit
one uniform colour, usually a pale rose pink, the “ coste”
partake of the faint-blue tint observable in the surrounding
field of vision; and lastly, that, in accidentally fractured
valves, the intra-costal spaces are left more or less entire,
like the teeth of a comb, attached to the median portion of
the valve, which is precisely the opposite of what would
occur did the intra-costal bars constitute the thinnest por-
tions of the valve, whilst the cost are the thickest.

In the genus Navicula, we find this kind of structure
modified, but in a slight degree ; and this, it appears to me,
has not been clearly shown heretofore, inasmuch as the very
term ‘ striz,’? which is specially employed to indicate the
structure, at once suggests the idea of projecting lines, or
bands minutely scored across, at intervals; whereas the
difference between the markings in Pinnularia and Navicula
consists only in the depressed spaces in the latter genus
being so minute as to admit of their arrangement, at inter-
vals, in linear series across the valve, and thus appearing as
unbroken lines under the lower powers of the microscope.
In this imstance, the definition, “resolvable into circular
dots,” is strictly accurate.

In the monstrosity which has been dignified with the
name of “ Surirella craticula,’ we at times meet with the

Watticu, on the Diatom-valve. 139

striation of Navicula, and the canaliculate structure of
Surirella, associated on distinct portions of the same valve.
In a specimen in my possession, from Bengal, and a similar
one from the Channel Islands, the central third of the valve
is distinctly striated, whereas the two outer thirds exhibit
the canaliculate character, in respect of which this form has
been referred to Surirella. In vol. u, p. 97, of the ‘ Journal
of the Microscopical Society,’ Professor Gregory has described
a similar form as occurring in the ‘‘ Mull deposit ;” and
alludes to the so-called “ canaliculi” being “‘ bars.” Under
my view of the structure in Pinnularia, to which genus the
diatom in question bears much closer resemblance than to
Surirella, the spaces between the bars are the analogues of
the “costz,’ whilst the bars constitute the intra-costal
spaces. I would here beg leave to state that, in retaining
the term “‘ costz,” as ordinarily applied, which is much more
applicable to the intra-costal spaces than to the parts which
have hitherto received it, 1 am guided solely by the desire of
avoiding inconvenience invariably attendant on changes of
the kind.

In Pleurosigma, on the other hand, the intra-linear spaces
constitute the strongest portions of the valvular plate. In
P. formosum there exists good evidence to prove that the
intra-linear spaces are occupied by elevated rhomboidal
papille, which present facetted surfaces; whereas in P.
Balticum, instead of rhomboidal elevations, we have four-
sided flattened pyramids, presenting, as in the former case,
four sets of lines, of which those bounding the spaces, and
not those crossing them, are the predominant ones.

Again, taking into consideration the secondary internal
valvular plate, the existence of which is constantly seen in
some species, it is not improbable that such a structure may
occur throughout the whole family, although incapable of
separation in most examples. From the modified impress of
the markings of the external plate found upon that beneath
it—as, for example, in Cocconcis—it is clear that, to a
certain extent at all events, the markings of the external
surface of the primary plate are traceable on its internal
aspect. Much additional evidence must, however, be forth-
coming, before this question can be satisfactorily settled.

A good deal of misconception has arisen from the sup-
posed analogy between the markings in Triceratium, in which
hexagonal structure really occurs, and those in Pleurosigma,
in which the appearance of hexagonal cellulation is only
observable under deceptive instrumental adjustments. In
the one case, the hexagonal spaces constitute the thinnest

140 Waxticu, on the Diatom-valve.

portion of the valve, and fracture takes place through their
centres ; whilst in Plewrosigma, the intra-linear spaces, which
are held, but erroneously, to be equivalent to the hexagonal
spots, constitute the strongest portion of the valve, and
fracture never takes place through them, save when undue
force happens to be employed. That the error in this case
originates in a misconceived analogy, is evident from the
subjoined quotation :—“ The valve is thinner and weaker at
the parts occupied by the dots; so that the line of fracture
corresponds to these parts.” And agai—“In those
(Pleurosigmas) requiring the use of oblique light and stops,
the line of fracture also corresponds to the rows of dots,
provided the light is equally oblique on all sides; and the
same appearances are presented by the dots in both cases,
beginning with those in which they are large (as Isthmia), to
those of moderate size (as in the species of Coscinodiscus),
down to those in which they are extremely minute (as in
Gyrosigma, &c.). Moreover, analogy affords us very strong
confirmatory ground; for the Diatomacee form a very
natural family, and if the dots are depressions m some
genera, we might expect them to be so in others. Had
these dots (im Gyrosigma) represented elevations, the valve
would have been stronger at those points.” (¢ Micrographie
Dict.,’ new ed., p. 34.)

If we take into consideration the outline of the more
marked discoidal forms, for instance, Triceratiwm and Cosci-
nodiscus, and contrast it with that of the Naviculoid group,
such as Navicula or Pleurosigma, it appears to me that we
might naturally expect to find the markings in the two types
exhibiting some distinct relation to the outlme. Now, inthe
genera which exhibit the honeycomb structure—that is, where
we find the appearance of a number of little hollow cylinders,
of considerable relative depth, and open outwardly in so far

as the siliceous wall is concerned—the conversion of elemen-.

tary circular cavities into hexagons is exactly what would
result from pressure exerted equally in every direction. Ina
small but well-marked species of Coscinodiscus, C. nitidus,
Greg., the markings are always circular, the distance between
them being too great to admit of their shape being modified
by the pressure of each cellule upon those adjoining it. The
same holds good of a small Triceratium, closely allied to Mr.
Brightwell’s 7. punctatum.

_ In Isthmia we meet with shallow cellules, or rather depres-
sions, varying in different frustules, in different gatherings,
and in different parts of the same valve, from irregular circles,
to irregular hexagons, parallelograms, and pentagons, accord-

Wattutcn, on the Diatom-valve. 4b

ing as they are situated on plane or curved portions of the
valve; thus proving most clearly, that the figure of the cel-
lules is modified, as I have asserted, by the configuration of
the entire frustule.

Advancing from the discoidal group, presenting haxagonal
cellulation, we are gradually led, first through Campylodiscus,
and then Surirella, to the Naviculoid group, exhibiting what
is called ‘‘striation.”

In Campylodiscus cribrosus we meet with circular or sub-
circular markings. In C. Hodgsonii, the circular and the
canaliculate are combined, or rather occur at definite portions
of the valvular surface; the canaliculi being arrayed con-
formably to the curvature of the valve. This last feature is
to be seen still more markedly in C. spiralis, whilst in
Surirella fastuosa we have the connecting bond between
Campylodiscus and the Naviculoid forms; specimens of
C. fastuosa, from the Channel Islands, presenting a distinct
flexure at right angles to the true axis of the valve, as in the
last-named genus.

Although our knowledge of the precise share taken in the
secretion of the siliceous valve, by the primordial utricle, is
lamentably deficient, certain facts crop out, here and there,
which it may be well to record under one head, with a view
to facilitate further inquiry. We know, for instance, that the
frustules of the Diatomacez, like the fronds of the Desmidiaceze
are encased in a gelatinous layer or envelope. In some
genera, this envelope is highly developed; in others it is not
so. But from the invarible obscurity of the markings upon
all, until the siliceous surface is cleaned by the application of
acids or heat, it is certain that such envelope exists indis-
criminately in the whole tribe. Judging, therefore, from the
impermeable character of the siliceous wall, it is highly
probable that the gelatinous stratum is secreted by the pri-
mordial utricle, through the marginal aperture of the valve,
much in the same way as the epiderm of the molluscous
shell is secreted at the margin of the mantle. Like the
latter, moreover, it is probably intended as a protection to
the subjacent structure. Of its highly elastic nature we have
ample proof, as was shown in a paper communicated by me
to this Society a short time ago. We can hardly doubt its
vitality, therefore; and we are thus furnished with presumptive
evidence that the invisibility of the motile filaments, whose
existence I endeavoured to demonstrate inferentially, is due
to the same cause that enables this gelatinous stratum to defy
our optical appliances. .

Another element of difficulty in the resolution of valvular

142 Waxuicu, on the Diatom-valve.

structure consists in a portion of the connecting zone being
sometimes projected under the surface of the valve, and faintly
impressed with its markings, as we find to be the case in
Epithemia gibba, Stauroneis pulchella, and Nitzschia specta-
hilis. In Stauroneis pulchella and Cocconeis placentula, the
peculiar wavy appearance which is superadded to the valvular
structure would appear to be due to this cause.

I cannot better describe the markings on the valves of
Pleurosigma formosum and P. Balticum, than by comparison of
what is seen in the first to a wafer-stamp, or neck of a gun-
stock; whereas, in the last, we have the form of marking
that would result, were an impression taken of a wafer-stamp,
in which the rhomboidal figures were replaced by flattened
four-sided pyramids. In both cases there are four facets,
inclined at a moderate angle to the plane of the surface ; and
two of the four sets of lines they exhibit can be brought into
focus more readily than the other two. The reason of this is
obvious. The diagonal series in P. formosum, and the rect-
angular in P. Balticum, being arranged strictly on the same
plane, are capable of being brought into accurate focus simul-
taneously. They constitute the thinnest portions of the valves.
Whereas the longitudinal and transverse series in the first
species, and the diagonal in the last, being constructed of a
series of short zigzags following the rise and fall of the
facetted portions, cannot be brought into focus at all points
with equal exactness; and form the thickest portions of the
valve. The distance, moreover, between the several sets of
lines being different, the closer series are more difficult of
resolution. The first-named cause is, however, by far the
most powerful.
_ Without taking upon myself the unnecessary task of prov-
ing a negative, I would briefly state my reasons seriatim for
rejecting, as wholly inconclusive, the arguments cited in
proof of the hexagonal structureof Pleurosigma angulatum, and
also the evidence based upon the photographic representation.

The analogy derived from what is seen in Triceratium and
Isthmia has been shown to be fallacious.

It is admitted by the advocates of the hexagonal structure
that, under imperfect adjustments of the microscope, “ hexa-
gonal dots” may be made to appear quadrangular or trian-
gular; and that those dots which cannot be conceived to be
really hexagonal may be made to appear so.

In Pleurosigma Balticum or P. hippocampus, by imperfect
adjustments, the appearance of hexagonal structure may be

produced quite as vividly as it can be made to appear in P.
angulatum.

be eG NaS

_ =

it

Waxtuicu, on the Diatom-valve. 143

~ Inasmuch as the photographic representation so constantly
appealed to is stated to be partly in perfect focus, and partly
out of focus, whereas the structure is equally distinct on
both parts, and the only difference observable consists in
the reversal of the lights and shadows, it is much more pro-
bable that one portion was as much without the true focus as
the other portion was within it.

From the woodcut of the photographic picture, it would
appear that the thickness of the walls of the hexagonal cel-
lules is equal to half of their diameter. Now, the striz being
stated to be composed of dots, and the lines being estimated
at sogooth of an inch apart, the walls must measure in round
numbers >5;'5;,th part of an inch in thickness; thus pre-
senting a surface the outline of which ought to be readily
resolved by the same powers that show the diagonal markings,
—for stance, by a quarter-inch objective,—did the hexagonal
structure really exist. -

_ It is highly improbable that hexagonal structure should
present itself in one species or group of a well-marked genus,
whilst a totally different structure is admitted to exist in the
other species of the same genus.

In proot of the rhomboidal structure, I beg, on the other
hand, to offer the subjoined proofs.

Under the application of any powers, ranging from } to +4
of an inch focus, so long as definition remains unimpaired, the
rhomboidal structure is invariably discernible; the diagonal
lines bemg predominant and visible, with perfect clearness, in
the case of the rhomboidally marked group, whereas the rect-
angular series 1s so in the other.

The object retained in one position on the stage, when
viewed under a given power, say a 75-inch objective and
a low eye-piece, exhibits oblique lineation and rhomboidal
facetted spaces, with perfect definition; whereas, by re-
placing the low eye-piece with a high one, and making any
alteration of focus demanded by the change, the hexagon-lhke
structure exhibits itself, but with imperfect definition.

By causing the rotation of the slide, containing either the
rhomboidally or rectangularly marked forms, at every forty-
five degrees a fresh series of lines will predominate, according
to the direction of the illuminating rays; each of the four
series being, of course, twice repeated in one complete revo-
lution, and the change of series therefore taking place eight
times.*

* As the longitudinal and transverse series of lines in the rhomboidal
group, and the diagonal series of the rectangular group of Plexosigmas,
require much more careful adjustment than the predominant series, for

VOL. VIII. p

te

144 Wauticu, on the Diatom-valve.

Were the structure hexagonal, these changes could not
occur in the foregoing order or number; for, inasmuch as
in any hexagonal arrangement only three series of lines are
present, being disposed on the same plane, the changes to
the predominant series would take place six times only,
namely, at every 60° in a complete revolution, each series
being twice repeated.

It has been pointed out by Mr. Hunt (‘ Journal of Microsco-
pical Science,’ vol. i, p.175) that the boundaries of a portion ofa
valve, belonging to one of the diagonally marked group, to
which moisture had accidentally gained access, were in strict
accordance with the view of diagonal lineation ; whereas they
were not reconcilable with any other view of the structure.
A similar fact may, at any time, be witnessed in balsam-
mounted specimens to which air has gained partial access, or
in dry mounted slides, affected by the ordinary atmospheric —
moisture.

Lastly, the lines of fracture, as before stated, mvariably
tally with the thinnest portions of the valves in the two groups,
that is, with the diagonal series in the one, and with the
longitudinal and transverse series in the other; a result at
variance with the indefinite lines of fracture observable in true
hexagonal structures.

Without reverting, then, to theoretical points, I would sum
up the general conclusions for which I conceive sufficient
evidence has been adduced. ‘They are as follows :—

That the growth of the diatom valve ceases entirely, either
at the period of its liberation from the connecting zone of the
parent valve, or immediately afterwards.

_ That, subsequently to this period, no change of configura-
tion takes place in the siliceous valve, except along its
margin, where fresh siliceous secretion may, under certain
conditions, be produced.

That the normal figure of all markings whatever is circular,
or approaching thereto.

That these markings are arranged on the surface of the
diatom valve in a determinate order, according to the inhe-
rent tendency of the species; but that the ultimate figure of
those markings is due to forces exerted wpon the young yalve,
whilst in a plastic condition, and retained within the connect-
ing zone of the parent frustule.

And lastly, that variation in size, and in the degree of fine-

reasons already given, they may be left out of the proof, if the experimenter
desires, without in any degree vitiating the result; for, in this case, the
change to the predominant series only, would oceur four times, instead of
eight, in.a complete revolution, namely, at cach 90°,

}

ie

Watticu, on the Diatom-valve. 145

ness or coarseness of the markings, is, within given limits,
dependent on the conditions under which the sporangeal
frustule gives egress to the germs of the new generation ; but
that the ordinary process of division is, of itself, sufficient to
bring about great variation, when operating through a vast
succession of individuals.*

* In the discussion which followed the reading of Dr. Wallich’s paper,
Mr. Wenham stated that, with an object-glass of his own construction,
having a focal distance of about sth of an inch and a large aperture, he had
ascertained beyond doubt, that in Pleurosigma angulatum, and some others,
the valves are composed wholly of spherical particles of silex, possessing high
refractive properties. And he showed how all the various optical ap-
pearances in the valves of the Diatomacee might be reconciled with the
supposition that their structure was universally the same.—{Zds. |

ORIGINAL COMMUNICATIONS.

On American Diaromacez. By Arruur M. Epwarps, Esq.,
New York, U. S.

A paper of mine, on American Diatomacez, was read
before the London Microscopical Society, March 30th, 1859,
and published in their Transactions, in which an omission
occurred which [ herein wish to rectify. A mistake occurred
in re-writing, so that the description of the species found at
Charleston harbour, 8. C., was left out. A paper on this
subject, by the present writer, was read before the New York
Lyceum of Natural History, February 21st, 1859, a copy of
which is annexed :—

On the Microscopic forms of the Harbour of Charleston, South
Carolina.

In the year 1850, Professor Bailey published in the ‘Smith-
sonian Contributions to Knowledge,’ a list of the microscopic
organisms which he had found in mud collected from the logs
of wharves, and from other situations in the harbour of
Charleston, S. C., which contained two new species, besides
many other curious forms; and in the year 1858, he de-
scribed four species of Ehrenberg’s genus Auliscus, three of
which are also found at Charleston, though Bailey failed to
detect them. Bailey’s list is as follows :—

Actiniscus sirius, hr. Navicula sigma, Lh.
Actinoyclus bioctonarius, hr. Pinnularia interrupta, ZAr.
Actinoptychus senarius, Lr. x didyma, Zhr.
Biddulphia pulchella, Gray. " lyra, Phr.
Cocconeis scutellum, Zh. Raphoneis rhombus, Fhr.
Coscinodiscus eccentricus, Zh. Stauroptera aspera, Hhr.
Dictyocha fibula, Zhr. *Surirella cireumstuta, B.
Eupodiscus Rogersii, Zh. Terpsina musica, Lhr.

ag radiatus, B. Triceratium favus, Zhr.
Gaillionella suleata, Zhr. alternans, B.

Certain of these have been re-named by later observers,
VOL. VIII. L

128 EDWARDS, ON AMERICAN DIATOMACE.

or have been found to be synonymous with already described
species, and should be designated thus :—

Coscinodiscus actinoptychus, Hd.
Actinopheenia splendens, Shad.
Eupodiscus argus, Hhr.
Navicula didyma, K.

» lyra,
Doryphora amphiceros, K.
Stauroneis pulchella, W. S.
Tryblionella scutellum, W. S.
Orthosira marina, Hhr.

Actinocyclus bioctonarius, Ehr.
Actinoptychus senarius, Er.
Eupodiscus Rogersii, Ehr.
Pinnularia didyma, Hhr.

- lyra, Ehr.
Raphoneis rhombus, Fhr.
Stauroptera aspera, Zir.
Surirella circumstuta, B.
Gaillionella sulcata, Hhr.

Actiniscus sirius, Ehr., and Dictyocha fibula, Ehr., are
neither of them Diatoms, and are most probably portions of
the skeleton of a Holothuria.

Some two years back, I received from a friend residing at
Charleston some of the so-called black “ pluff’’? mud, taken
from between watermarks, and which I found to be extremely
rich in Diatomaceous forms. The following species were
observed :—

Hu eon wet a

Actinocyclus undulatus, Zhr. Epithemia Hyndmanii, W. S.
Actinopheenia splendens, Shad. as musculus, K. ~
Auliscus celatus, 2B. Navicula didyma, K.
»» pruinosus, B. E tak tt maculata, 2. sp.
» punctatus, B. eae permagna, 7. sp.
Biddulphia rhombus, V7. S. Nitzschia sealaris, W. iS.
ss aurita, Bréb. Pleurosigma angulata, W. S.
Campylodiscus cribrosus, WV. S. Triceratium alternans, B.
Cocconeis scutellum, Zhr. favus, Hhr.
Coscinodiseus actinoptychus. Edw. punctatum, 7. B.
‘5 eccentricus, Dir. Tryblionella scutellum, WS.
a lineatus, Lhr. P. punctata, WS.

a oculus-iridis, Bhr.
a radiatus, Hhr.
55 subtilis, Dkr.

The Navicula sigma, Ehr., of Bailey’s list, is most probably
synonymous with the Pleurosigma angulata, W. S., of mine.
Chose species marked with an asterisk (*) are new, and are
characterised as follows :—

Navicula maculata, n. sp.=Stauroneis maculata, B., 1850.

a Lanceolate or elliptical; ends slightly produced and
rounded ; surface punctato-striate, with a large smooth cen-
tral space.” Bailey. To this description I have to add the
following measurements : length 055 in. ; breadth -00216 in. 5
strive coarsely moniliform, 12 in. ‘001 in.
Navicula permagna, n. sp.=Pinnularia permagna, B., 1850.

“‘ Large, lanceolate on the ventral faces, with punctato-
striate marginal bands, and a broad, smooth central stripe ;

j

EDWARDS, ON AMERICAN DIATOMACES. 129

ends slightly rounded.”’ Bailey. I have as yet only found
this species in small quantities, and have been unable to
make its measurements. There can be no doubt that these
two species should be placed in the genus Navicula, as the
seeming stauros in the first, the presence of which would
seem to rank it in that of Stauroneis, is only a blank space,
‘such as is seen in many species of Navicula, as N. elegans,
&e. The presence of moniliform striz in the second species
removes it from Pinnularia, which is characterised by its
markings being cost, not resolvable into dots. Of N.
macuiata, | have specimens from Duval’s Creek, near Enter-
prise, Florida, for which I am indebted to Dr. Christopher
Johnston, of Baltimore, Md.

I here mention a fact that has come within my notice
while examining this gathering. Smith’s Eupodiscus radiatus,
as described and figured in the first volume of his ‘ Synopsis,’ is
not the same as the form described under that name by
Bailey in 1850. Roper has remarked this same fact (‘ Trans.
Mie. Soce.,’ London, vol. vii, p- 19), but was in some doubt
until I had the pleasure of forwarding him authentic
specimens of it from Bailey’s cabinet, when he wrote to me
that the examination of them confirmed his opinion that
Smith was in error in referring the Thames diatom to that
species. Itis perfectly distinct, and a true Eupodiscus.

Since the above article was written, I have been lead, by
the advice of Dr. Arnott, to reconsider the subject of the
species, which I, in my paper on American Diatoms, called
Coscinodiscus actinoptychus. This belongs to Ehrenberg’s
genus Actinocyclus, the species of which are characterised by
the number of rays,—a loose character. It should therefore
be placed in that genus for the present, the specific name
being left blank until more is known of its natural history.

130

TRANSLATION.

AgvmospHeric MicrocrapHy. Osservations on the Cor-
puscLes suspended in the AtMosPpHERE. By M. Povucuer.

(‘ Comptes rendus,’ March 21st, 1859.)

Tuer atmosphere contains, in suspension, numerous cor-
puscles, consisting of the detritus of the mineral crust of the
earth, animal and vegetable particles, and the minutely
divided débris of the various articles employed in our wants.
These various kinds of corpuscles are more numerous and
more voluminous in proportion to the degree in which the
atmosphere is agitated by the wind; and they constitute
what we term “ dust.”

This “dust” being simply the deposit of the corpuscles
carried in the atmosphere, it is evident that the attentive
study of its composition is simply a microscopic analysis of
the air.

The granules of mineral origin, partly going to form the
dust, present but little variety. They are derived essentially
from the detritus of the rocks which are exposed in the
country where the dust is observed.

The débris derived from the animal kingdom consists
chiefly of the following articles :—various animalcules in a
dry state and of extreme minuteness, such as entozoa be-
longing to the genus Oxyuris and Vibriones of several
species. I have often also noticed the skeletons of siliceous
Infusoria, especially of Navicule, Bacillarie, and other
diatoms; fragments of the antenne of Coleoptera; scales of
diurnal.and nocturnal Lepidoptera; fibres of wool of various
colours derived from our clothes, often of a beautiful blue,
bright red, or green; hairs of the rabbit, bat, &c.; the
barblets of feathers; fragments of the tarsi of insects ;
epithelial cells; fragments of the skin of various insects;
particles of cobweb. Twice only, in more than a’ thousand
observations, have I observed one of those large ova of
Infusoria having a diameter of 00150 mm., denominated by
naturalists “ cysts.’

The corpuscles contained in “ dust?’ belonging to the vege-
table kingdom, observed by me, are the following ;:—frag-

ee

POUCHET, ON ATMOSPHERIC MICROGRAPHY. 131

ments of the tissue of various plants; a few ligneous fibres ;
more frequently fragments of cells and vessels; often hairs of
the nettle and other plants; numerous filaments of cotton,
usually white, but sometimes of various colours, also derived
from articles of dress; some fragments of anthers and pollen-
grains of malvaceous plants, of Kpilobium and Pinus ; spores
of cryptogamous plants, but in very small number. Lastly,
I have constantly noticed, and almost invariably where my
observations have been extensive, a very notable quantity of
wheat-starch mixed with the dust, whether recent or old;
and, in rare instances, may be found the starch of oats,
barley, and the potato.

It is evident, therefore, that the atmosphere holds in sus-
pension a certain quantity of wheat-starch among its dust-
corpuscles. This substance is met with in all places where
it enters into articles of food, and it may readily be distin-
guished by its physical and chemical characters. The grains
of which it consists are sometimes ovoid, sometimes spherical ;
in diameter they usually vary from 0-0140 to 0:0280mm.
Besides these numerous extremely minute incipient granules,
may be seen others less than 0-0028mm. in diameter. The
larger grains are very rare; those of a medium size far
more common, and the very minute ones extremely abundant.
In the large granules the concentric layers and hilum may
sometimes be readily distinguished. It is rather curious to
remark that this starch, notwithstanding, in some instances,
its secular existence, still affords all the physical and chemical
properties of the recent substance. The only difference
being that the very ancient presents a light-yellow tint.
When boiled in water it swells and dissolves. Very weak
hydrochloric acid has no effect upon it ; it is coloured blue
by iodine with greater or less intensity; and sometimes its
colour disappears under the influence of ight. One circum-
stance which has struck me, is, that among starch found in
dust several centuries old, I have, from time to time, met
with grains which had spontaneously assumed a beautiful clear
violet colour. Was this due to the influence of time, or to
the vicinity of the sea, or, lastly, according to M. Chatin, to
the traces of the vapour of iodine contained in the atmo-
sphere? Finally, that no doubt may be entertained with
respect to the identity of this aérial fecula with ordinary
starch, I would add, that its effect upon polarized light is
the same, except that, when procured from a very ancient
deposit, its polarizing property is less energetic.

It is evident that it is this fecula thus perfectly charac-
terised by its physical and chemical properties, that M. De

132 POUCHET, ON ATMOSPHERIC MICROGRAPHY.

~

Quatrefages has taken for the ova of microzoa. It is the
most minute grains of this substance to which he refers when
he states, that he “ could easily recognise in the dust” several
of those minute corpuscles of a spherical or ovoid form, well
known to all micrographers, and which involuntarily suggest
the idea of an extremely minute ovum.* This image is
correct, but the illusion is at once dissipated by the slightest
chemical test, which proves that the granules in question
can be nothing else than either extremely fine amylaceous
grains or siliceous particles, which I have frequently ob-
served, and which are of such extreme tenuity, as under the
microscope to present the appearance of transparent spherical
granules.

Astonished at the comparative abundance of the amyla-
ceous particles which I found among the atmospheric cor-
puscles, and in order to obtain a rigorous demonstration of
the fact, I determined to examine dust of all ages and from
all localities. I have investigated the monuments of our
great cities, others on the sea-shore and in the desert; and,
in the midst of the immense variety of corpuscles universally
floating in the air, have almost everywhere met with starch
in greater or less abundance. Gifted with an extraordinary
self-conservative power, time seems scarcely to affect it.

However remote may be the antiquity of the atmospheric
corpuscles, starch still recognisable is found among them. I
have discovered its presence in the most inaccessible recesses
of our old Gothic churches mixed with the dust, blackened
by an existence of from six to eight centuries. I have even
found it in the palaces and subterranean chambers of the
Thebaid, where it would date probably from the epoch of the
Pharaohs.

It may be affirmed, as a general proposition, that in all
countries where wheat constitutes the basis of food, its
starchy element penetrates everywhere with the dust, and is
found mixed with it in more or less considerable quantity.
It is more abundant in situations pear the centre of towns
and at a low level, whilst, in proportion as we go to greater
distances from the great centres of population, and explore
the more isolated monuments, does the starch become less
and less abundant, and its grains more and more minute.
I have been unable to detect any either in the Temple of
Jupiter Serapis, situated on the shores of the Gulf of Baize,
or in that of Venus Athor, placed on the confines of Nubia.
Nevertheless, I have collected some in subterranean temples
of Upper Egypt.

* “Comptes rend.,’ Paris, 1859, t. xlviii, p. 31.

POUCHET, ON ATMOSPHERIC MICROGRAPHY. 133

It is remarked also, that in proportion to the elevation
reached on mountains or on buildings, the amount of fecula
mixed with the atmospheric detritus is diminished. In the
Abbey of Fécamp, which is below the level of the ground,
and situated in the middle of the town, starch abounds in
the dust of its chapels. In the Cathedral of Rouen a con-
siderable quantity is met with in the lower part of the
tower of Georges d’Amboise, the proportion gradually dimi-
nishing as we ascend. Whilst still abundant in the ancient
dust found in the roof of the choir, it becomes more and
more rare when we mount into the spire. Very little is
found at the base of the cast-iron pyramid, and not a single
grain at its summit.

In an isolated chapel situated on the sea-shore, and built
on a beach about 110 metres in elevation, the dust lodged
on a statue was composed, in great part, of calcareous
particles, derived from the sides of the mountain, and con-
. veyed by the wind to the floor of the building, which is open
day and night to pilgrims. In the same situation were also
found a great number of scales of lepidopterous insects, which
had, doubtless, often sought shelter there ; but very rarely was
a grain of starch perceived in the field of the microscope ;
whilst in the detritus of towns, on every trial, several grains
of a medium size, and a considerable number of more minute
dimensions, would have been noticed.

A battery also placed on the shore, and in an isolated situa-
tion, and which had not been opened for sixty years, afforded
a black dust, which was as poor in starch as that of the
chapel above mentioned. But the dust itself was of a wholly
different nature, being composed almost entirely of very
angular, transparent, colourless particles of silex. The
starch was so scarce in this dust, that often not more than
a single grain could be discovered in a dozen observations.

This dissemination is a phenomenon so general and so
widely diffused in places where wheat is used for food, that
there is no nook or corner into which starch does not in-
sinuate itself with the air. It is found im everything, and in
‘all situations into which the latter penetrates. The most
obscure corners of our Gothic buildings have afforded this
substance in the ancient dust which had never been dis-
turbed in the memory of man. I have even found it in the
interior of the cavity of the tympanum in the skull of a
mummified dog which I procured from a subterranean
temple in Upper Egypt. M. Ch. Robin, whose observatious
accord with mine, has discovered starch on the surface of
the human skin, whence it may be procured by scraping

134 POUCHET, ON ATMOSPHERIC MICROGRAPHY.

with a sharp instrument either in the dead body or of a
ing person.

arti tick observations, if it were needed, might be sup-
ported by biological proofs. Until the contrary can be
shown experimentally, it may be said that the air is so
rarely the vehicle of ova, and the dust so rarely their recep-
tacle, that when the latter is subjected to an elevated tem-
perature, it is no less fecund in animalcules than that which
has not been heated; which would not be the case, were the
hypothesis of aerian dissemination of ova founded in truth.

I have often repeated the following experiment. I have
taken 3 grammes of an ancient dust, and placed it in a
thin tube, heated to 215° C., in an oil-bath, for an hour and
a quarter. The dust has afterwards been put ito 30
grammes of artificial water, and the whole covered with a
bell-glass. At the end of five days, and at a mean tem-
perature of 20° C., the water was crowded with animalcules of
large size—Colpoda and Paramecium. The same result takes
place with dust which has not been heated. What has been
taken, therefore, for ova deposited from the atmosphere, was
not really such; for, in that case, the dust which had been
heated would have been infertile, the germs contained in it
having been killed by a temperature of 215°C.

Another very simple experiment also proves that it is
impossible to discover any living germ in the atmosphere.
By means of an inhaling flask I caused 100 litres of air to
pass through a safety tube whose bulb contained two cubie
centimetres of distilled water. At the end of eight days I
was unable to discover a single animalcule or ovum in this
small quantity of water, in which the latter, themselves, could
not escape observation, now that they have been completely
described and measured, and are well known in several species.
On the contrary, if I place in a cubic decimetre of distilled
water 5 grammes of a fermentable substance, sheltered
by a bell-glass having a capacity of one litre, at the end of
eight days, and at a temperature of 18° C., the whole surface
of the water is occupied by incalculable myriads of ani-
malcules.

The memoir concludes with the detail of particular observa- —

tions on dust collected in the following localities :

Tower of Georges d’Amboise, at Rouen. Interior of the
Abbey at Fécamp. Ruins of Thebes. Tomb of Ramses II.
Sepulchral chamber of the Great Pyramid. Temple of Venus
Athor, at Philoe. Temple of Serapis, at Puzzuoli. Skull of
a mummified dog, from the subterranean vaults of Beni-
Hassan. The cabinet of a Jewish antiquarian at Cairo.

135

NOTES AND CORRESPONDENCE.

Angular Aperture— My object in the paper on the subject of
angular aperture, which you were good enough to insert
(p. 256, last volume), was simply to facilitate the application of
Mr. Lister’s method of measurement, by showing how that
method might be made available independently of the special
apparatus usually considered requisite for this purpose. Mr.
Hendry, therefore (p. 61, present volume), is mistaken if he
supposes, as he seems to do, that I claim for the method, as
described by me, superiority in point of accuracy to the
method as usually practised. I do not do that, but I claim
for it eguality in this respect. An angle is determined quite
as accurately by measurement of the sides of the triangle to
which it belongs, as by measurement of its subtending are.
The use of two candles saves the trouble of moving the one
candle, if one only is used, from one side of the field of view
to the other; and the indication of these being properly
placed will easily be found to be im exact accordance with
the corresponding indication m Mr. Lister’s method, as
usually described.

But I am surprised at Mr. Hendry’s statement, that “ my
rule gave no provision for angles exceeding 90°.” I know of
no ground for this statement. Take his fourth example :

Lights apart, 44 inches; distance of lens, 10 inches.

Hence 44 + (10 x 2) = 2:2. On reference to Hutton’s
Tables, I find this to be the tangent of 65° 33’. The aperture
therefore is 131° 6’.

Mr. Hendry, perhaps, has only a table of logarithmic
tangents. Very well. The logarithm of 2:2 is 0°3424, to
which adding 10, to accommodate it to the tabular radius, it
becomes 10°3424; and this is the logarithmic tangent of
65° 33’, as before—M. Gray, 7, St. Paul’s Villas, Camden
Town, December 5th, 1859.

A New Cement for mounting Objects for the Microscope, either
in dry cells or in fluid—I have found that great rapidity is
obtained in mounting objects in a cement made with as-

136 MEMORANDA.

phaltum dissolved in Benzine or Benzole instead of turpentine,
because it dries so quickly that a great many more objects
can be mounted and finished in a day with it than with any
other cement. I finish it off with a coat of asphalt im tur-
pentine, to give it a smooth appearance.

It should be kept, like all cements for the mounting of
microscopic objects, in a capped bottle, so that the brush is
always soft and ready for use. |

Benzole is also the most convenient solvent for removing
superfluous balsam from the outside of the glass covers under
which objects are mounted in that medium.—J. W. Law-
RANCE, Peterborough.*

Registration of Objects—I beg to subjoin notice of a simple
mode of registering objects on slides, which was devised by
me in India, and has answered all ordinary purposes so effici-
ently as to induce me to hope it may prove useful to micro-
scopists.

It possesses three great advantages,—in requiring no sepa-
rate apparatus, no special adjustment of slides or stage, and
costing nothing. It is adapted for use with all the higher
powers of the microscope. Although more readily available
where the body of the instrument admits of lateral displace-
ment, it may nevertheless be used where no such arrange-
ment exists, by simply elevatmg the body to a sufficient
height to allow of the bearings of the spot of light given off
from the illuminator being accurately taken by the eye and
hand.

Suppose an object to be in the centre of the field of vision.
The body of the microscope is either turned aside or raised,
as the case may be. The slide being securely clamped m
position, two minute marks are made, with a writing diamond,
perpendicularly above, and in a line horizontal with, the spot
of hight thrown upon the object by the condenser. ‘The
smaller the spot of light, of course, the more easy will it be
to denote the situation of an object accurately. The slide is
now removed, and the scratches are converted into short
vertical and horizontal lines, varying in length according to
convenience. These two lines are now joined together by a
third line; and, lastly, a number is attached, at either angle
thus formed, for entry in the note-book or catalogue of the
observer.

To find the object again, all that has to be done is to place
the slide on the stage, and the body of the microscope being

* The addition of a little gold size to the solution of asphaltum in benzine
will be found useful in rendering it less brittle —{Eps.]

MEMORANDA. 713

either turned aside or elevated as before, to move the slide to
and fro, either by hand or stage movements, until the spot of
light from the condenser indicates the spot at which the
vertical and horizontal lines beyond the margin of the cover
would intersect each other, if produced.

Of course, upon the accuracy with which the bearings have
been taken will depend the facility of finding an object. But
with ordinary care and a tolerably true eye, there is no diffi-
culty.

The following diagram will show the mode of registry, and
how it may be applied to any number of objects on the same
slide—

The dots, it is almost unnecessary to remark, are appended
merely with a view to indicate the points at which the objects
to be registered occur.—G. L. Wauuicn.

Improvement of the Camera Lucida.—One of M. Nachet’s
ingenious applications of the prism to the microscope fur-
nishes a hint for the improvement of the camera lucida,
which I desire to bring under the notice of yourself and your
readers. I refer to the arrangement described and figured
on p. 706 of the second edition of Dr. Carpenter’s work on
the microscope. A prism of peculiar form is there seen, ap-
plied as a camera lucida to a vertical microscope.

To the arrangement in question, as a whole, do not attach
much importance; for, first, our English microscopes are
generally of too tall a duild to admit of being at all commo-
diously used in a vertical position for any length of time ;
and, secondly, if they could be commodiously so used, the
stage would be in the way of the hand; while, moreover, the
paper not being in the place where 7¢ seems to be, but away
in front of the instrument, I venture to think that this would
seriously interfere with the free use of the pencil in tracing
the image.

It is to a small adjunct of M. Nachet’s prism that I
refer, as holding out a prospect of advantage; I mean the
piece, marked b, in Dr. Carpenter’s figure. It is well known
that many—perhaps most—microscopists find considerable

138 MEMORANDA.

difficulty in using the camera lucida as at present constructed,
owing to the constrained position in which the eye must be
held, half the pupil over and half beyond the edge of the
prism. A partial remedy for this difficulty would be found in
discarding the present form of prism, with its two reflecting
surfaces, and using a prism having only one such surface, and
drilling a small hole through it vertically. Through this hole
the paper would be seen, while the image would be visible by
the rays reflected from the inclined surface of the prism.
The objection to this is that the hole would act, as regards
the rays entering the prism, as an opaque rod, and so render
useless the portion of the reflecting surface immediately
behind it. A complete remedy for the difficulty is suggested
by inspection of Dr. Carpenter’s figure. Instead of making
a hole in the prism, let there be attached to the centre of
its inclined surface, by Canada balsam, an oblique segment
of a small glass cylinder,* so that its base should be pa-
rallel to the upper surface of the prism. The effect now,
on looking into the prism, will be precisely that of a
a hole through it, without the drawback attendant upon an
actual hole. The paper will be clearly seen through the
prism and the cylinder, and the image by reflection from the
inclined surface of the prism, the whole of which surface will
now be available, with the exception of the spot where the
cylindrical segment is attached, which, however, will be so
small as not to be productive of any injurious effect. In fine,
so far as I at present see, I feel warranted in expressing a
belief that by the adoption of the arrangement now suggested,
the difficulty hitherto attendant on the use of the camera
lucida would be entirely prevented.

It has often been matter of wonder with me why our
opticians continue to supply, for microscopical purposes, the
prism with ¢wo reflecting surfaces. These are requisite in
other applications of the camera, for the erection of the
image. But in its application to the microscope we do not
want this.t What we want, if we had a preference in the
matter, is that the inversion caused by the first reflection be

* Dr. Carpenter calls Nachet’s “ piece £” a prism. I think he must be
wrong. The quasi hole will be of the form of a direct section of the piece
employed. A square prism would give a square hole, and a cylinder a cir-
cular oue. :

+ A polished steel dise (Amici’s disc) has sometimes been employed
instead of the more usual Wollaston’s camera. But the latter will always
be preferred by those who draw from the microscope, simply for the reason
that the image thrown on the paper by it corresponds in position with that
viewed through the microscope.—[Ebs. }

MEMORANDA. 139

left alone. I should think that a prism with only one re-
flecting surface would be much more easily worked than one
with two. A prism of the latter form, however, is spoiled
by the slightest clipping of the edge; while, in the arrange-
ment I have proposed, the edge does not come into use—and
it might perhaps be found more advantageous in the working

to have the edges truncated.—P. Gray, 7, St. Paul’s Villas,
Camden Town, N.W.

On the Rarer and Unpescrisep Sprcizs of DiatoMacEs.
By T. Brieutweit, F.L.S. Part II.

ERRATA ET CORRIGENDA.

I regret to find the following errors have crept into my
last paper which need correction.

TEXT,
Page 94, line 4, insert reference to plate “ (Pl. VI, fig. 15).”

» 94, 4, 8, for “tig. 15,” read “18.”

» 94, 4, 4 from bottom, zxstead of “Aulacodiscus,? read “Auliscus
sculptus = A. celutus, Bailey. *

» 95, line 1, for “ Aulacodiscus,” ‘read “ Eupodiscus.”?

» 95, ,, 6, “ Aulacodiscus levis”? I find this form has been named
and distributed by Dr. Arnott as “4 Kitloni;” the specific name
of “‘/evis’”? must, therefore, be cancelled, and ‘* Kittoni” substi-
tuted.

» 95, line 19, the specific name should be “ coscinodiscus,” instead of
* pyxidicula.”

» 96, line 6, for “ -019 to 0°3,” read “+0019 to 0030.”

One general error runs through all the measurements ; they require an
additional ‘0 in front.

DESCRIPTION OF PLATES.

Plate V.

Fig. 2, insert specific name “ trilingulatus.”
» 4, for “ pyxidicula,” read “ coscinodiscus.?
» 9, for “ Aulacodiscus,’ read “ Auliscus.?

» 6, insert specific name “ coronatus.”
wry 22
ay ee as per ak Marg nitus.
a eel 9 » * cervinus. .
» 10, for “ Aulacodiscus,” read “ Lupodiscus.
Plate VI.
Fig. 11, izsert specific name “ radiata.”
LOL. 5, a nme semiplanus.”
» 13, »” ” ” © Kittont.
“<c Seo ta, 9
” 15, ” ” » Splnosa.
ig “6 » “* stylorum.

>” ” ‘ ‘ EP
» 17, for “ Eupodiscus,” read “ Actinoptychus interpunctatus.

140

PROCEEDINGS OF SOCIETIES.

MicroscoricaL Socrery, January 11th, 1860.
Dr. LaNKEsTER, President, in the chair.

Tur minutes of the preceding meeting were read and ~
confirmed.

J. A. Tulk, Esq., 5, East Preston-street, Edinburgh ;
J. C. Forsyth, Esq., Stoke-upon-Trent ; and George Kelly,
Esq., 9, Sutherland-gardens, Maida-vale, were balloted for,
and duly elected members of the Society.

The following papers were read :

1. ‘On the Localities of Diatomacez,’ by Mr. Norman.
(‘ Trans.,’ p. 59.)

2. “On the Reproduction of Confervoid Alge,’ by Mr.
Druce. (‘Trans.’, p. 71.) * ‘

The following letter, addressed to the President, was —
read :—

“My pear Sir,—l send you three slides of the same object.

‘No. 1, mounted in balsam, without any preparation except
washing away the salt water.

“No. 2, the same burned on the cover, and mounted dry.

“No. 3, the same neither boiled nor burned, and mounted ~
in fluid. It is probable that, in this last, all the objects may,
during the transit, be deposited on one side of the cell, but a —
little shaking will perhaps cause them to become again —
scattered, as they were when mounted. .

“The first time that it came under my notice, it was sent me,
11th September, 1858, by the Rev. R. Taylor, of Bedlington,
from the coast of Northumberland. I afterwards received it
from Mr. Mansfield Browne, of Liverpool, collected on that —

coast. Thereafter it was sent me by Mr. Roper, from the —

Norfolk coast ; by Mr. G. Norman, of Hull, from near the
mouth of the Humber; and the other day, I received an
immense quantity of it from Mrs. Macdonald, of St. Andrews, —
Fifeshire. ;

“Tn all these cases it is found on very shallow pools among _
the sands; it floats on the surface and forms extensive patches.
If sand adheres, it is easily separated by a slight shaking in
the bottle in which it is colleeted. .

PROCEEDINGS OF SOCIETIES. 14]

“Some have supposed it a diatom allied to Biddulphia
Bayleyt. From its filamentous nature, and having long spines
or cilia, it might, if diatomaceous, be approached to Biddul-
phia; but it takes in turpentime and balsam when dried without
being boiled or burned. Now this can only take place on the
supposition either that there are no partitions (or valves at
the jomt—ain other words, that the tube is continuous), or that
the wall is porous; either of which is contrary to its being a
diatom at all.

“Some of my correspondents suppose it to be the exuvize of
an annelid; but no one can point out either genus or
species.

“An object of such abundance on our coasts (at St. Andrews
I am informed that a pint of it could have been collected in a
few minutes) must surely be well known to the London
microscopists; and therefore I send you the slides in the hope
that, through its members, you will be able to throw some
light on the point.

“T shallsend a supply of the object itself to Mr. J. T. Norman,
the well-known preparer of microscopic objects; so that any
one requiring slides may have them from him. They are
best seen on the cover, dry, and not burned; but, unless
burned, they are apt to imbibe damp, and the slide becomes
useless in a year or two. I therefore, myself, prefer them
when mounted dry, after being burned.

“ Yours truly,

“G. WaLKER ARNOTT.”

‘© Victoria-terrace,
* Dowanhill, near Glasgow.”

Josh. Gratton, Esq., and R. Beck, Esq., were appointed
auditors of the Treasurer’s account.

February 8th, 1860.
ANNIVERSARY MEETING.
Dr. Lanxester, President, in the chair.

The minutes of the preceding meeting were read and
confirmed.

Reports from the Council and the Library Committee were
read, together with the Auditors’ Report on the Treasurer’s
accounts; there remaining in his hands a balance of
£25 16s. 10d.

Resolved that these Reports be received and adopted.

142 PROCEEDINGS OF SOCIETIES.

R. Lloyd, Esq., 69, Holborn-hill ; and H. W. Elphinstone,
Esq., 45, Cadogan-place, were balloted for, and duly elected
members of the Society.

The President delivered an address on the progress of the
Society, and of microscopical science generally, during the
past year.

Resolved, that the address now read be printed and circu-
lated in the usual manner, with the Reports of the Council,
the Library Committee, and the Auditors. :

March 14th, 1860.
Grorce Jackson, Esq., in the chair.

John Shepperd, Esq., 11, Sussex-place, Regent’s-park ; and
Thomas Ketteringham, Esq., 51, Coleshill-street, Chelsea,
were balloted for and duly elected members of the Society.

The following papers were read :—

‘On the Development of the Diatom-valve,’ by Dr.
Wallich. (‘Trans.,’ p. 129.)

‘On Asterolampra, and some other species of Diatomacez,’
by Dr. Greville. (‘ Trans.,? p. 102.)

‘On the Ameeboid Conditions of Volvox globator, by Dr.
Hicks. (‘Trans.,’ p. 99.)

‘On a New Zoophyte,’ by Dr. Allman. (‘ Trans.,’ p. 125.)

143

ZOOPHYTOLOGY.

SHETLAND Poryzoa. Collected by Mr. Barter. (Continued.)

2. L. Barleci,n. sp. Pl. XXVI, figs. 1, 2.

L. cellulis ovoideis, convexis, superficie granulosé ; orificio orbiculari infra
sinuato, peristomate simplici elevato ; ovicellulis decumbentibus adnatis, ad
marginem supra perforatis.

Cells ovoid, convex; surface granular; orifice orbicular with a sinus
below, peristome thin, raised ; ovicells adnate, decumbent, punctured round
the border above.

Hab. Shetland, Bariee ; on shell.

3. L. canthariformis, n. sp. Pl. XXVI, figs. 3, 4.

L. cellulis late ovoideis, superficie granulosé, punctatd, nitida ; orificio
magno, suborbiculari seu irregulari, peristomate producto, sepius infundibuli-
Sormi, integro.

Cells broadly ovoid, surface granular, punctate, shining; orifice large,
suborbicular, oblong, or irregular ; peristome much produced, often infundi-
buliform, entire.

Hab. Shetland, Barlee ; on shell.

4. L. umbonata,n. sp. Pl. XXVII, fig. 1.

L. cellulis oblongis, seriatis, lined elevatd sejunctis ; ad latera perforatts,
medio umbonatis, et juxta orificium medio aviculurium mandibulo semicirculari
horizontali gerentibus ; orificio suborbiculari, infra paullulum constricto,
peristomate simplict spinis 4; supra armato; ovicellulis umbonatis vitlamque
parvam utringue ostendentibus.

Cells oblong, serial, parted by a narrow raised line, punctured on the
sides, and sometimes in front, with smaller pores; furnished with a central
umbo, and having a prominent avicularium with a semicircular horizontal
mandible immediately below the orifice; orifice suborbicular, or sometimes
contracted below ; peristome simple, with four spines above; ovicell large,
rounded, umbonate, with a small vitta or depressed area placed obliquely on
each side below.

Hab. Shetland, Bariee; on stone.

The only species with which this can well be confounded is
L. verrucosa, which possesses a similar -suboral avicularium,
but always wants, I believe, the central umbo on the cell and
on the ovicell, as well as the vitte on each side of the latter,
which are not unlike those on the ovicell of L. figularis, only
smaller. In ZL. verrucosa, also, the ovicell is punctured,

VOL. VIII. M

144. ZOOPHYTOLOGY.

whilst in ZL. umbonata its walls are apparently entire. The
umbo on the ovicell, it may be remarked, is merely that be-
longing to the cell in front of which the ovicell rises.

5. L. bella, nu. sp. Pl. XXVII, fig. 2.

L. cellulis ovoideis, perforatis ; orificio suborbiculari, infra sinuato, denticu-
lum internum bifidum ostendenti; peristomato, elevato, subinde incrassato,
inermi ; ovicellulis rotundatis perforatis.

Cells ovate, punctured; orifice orbicular, with a spout-like sinus below,
within which is a rather large, bifid denticle; peristome raised, often
thickened ; ovicell subglobose, punctured.

Hab. Shetland, Bariee; on shell.

This is the species which I doubtfully termed L. Landsbo-
rovii, when the account of Mr. Barlee’s species was read at
the British Association. It is clearly, however, not that
species as now understood, however much the figures here
given may seem to correspond with that of L. Landsborovii,
in Plate LXXXVI, of the ‘ British Museum Catalogue.” That
figure was taken from the only specimen of L. Landsborovit
contained in the Johnstonian Collection, and which was the
sole representative of the species I had then seen. Since
then, however, having received numerous and more perfect
specimens, I have been able to determine the characters of
the species more precisely; and Fig. 1, Plate CII, of the
‘ British Museum Catalogue,’ erroneously referred to L. reti-
culata, may perhaps be taken as representing its typical form.

The differences between L. bella and L. Landsborovii con-
sist—

1. In the absence in the former of the intercellular raised
line, and

2. In the absence of any avicularian organ on the lower
border of the orifice.

From L. reticulata and L. pertusa the differences are too
obvious to require more particular notice.

The other species of Lepralia which occur in Mr. Barlee’s
collection are—

6. L. Pallasiana, Moll.

7. L. bispinosa, Johnston.
8. L. granifera, Johnston.
9. L. ringeus, Busk.

10. L. discoidea, Busk. Pl. XXVII, figs. 4, 5.

The figure of this species, which in some respects closely
approaches an Alysidota, was inadvertently placed on the
stone, before I remembered that it had been already figured
in (‘ Zoophytology’) Pl. XXII, figs. 7, 8, from specimens

ZOOPHYTOLOGY. 145

collected in Madeira by Mr. J. Y. Johnson. As I am unable
to discover any satisfactory specific distinction between the
northern and southern forms, I am induced to consider them
identical.*

Other species belonging to the family Membraniporide,
which occur in Mr. Barlee’s collection, are—

1. Membranipora Rosseli, Savign.

2. ee Pouilletii, Savign.

3. ss spinifera, Alder.

4. Alysidota Alderi, Busk, which appears to be very abundant.

* In the paper read at the meeting of the British Association, this species
was termed Alysidota conferta.

(To be continued.)

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ZOOPHYTOLOGY.

DESCRIPTION OF PLATES XXVI & }

PLATE XXVI.
Fig.
1 and 2.—Lepralia Bazleei, p. 143.
3 and 4.—L. canthariformis, p. 143.

PLATE XXVII.

1.—Lepralia umbonata, p. 143.
2 and 3.—Z. bella, p. 144.
4 and 5.—L. discoidea, p. 144.

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