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THE
CAMBRIDGE NATURAL HISTORY
EDITED BY
S. F. HARMER, M.A., Fellow of King’s College, Cambridge ; Super-
intendent of the University Museum of Zoology
AND
A. E. SHIPLEY, M.A., Fellow of Christ’s College, Cambridge;
University Lecturer on the Morphology of Invertebrates
VOLUME III
ee feo eee ee | Ee
London: Macmillan &C°
15 W.Long: 0.E.Long:
lp
=
b
7
aia
cies
|
Map to illustrate
THE GEOGRAPHICAL DISTRIBUTION
of the
LAND OPERCULATE MOLLUSCA
eet
undicate the number of known sp:
a
MOLEUSCS
By the Rev. A. H. Cooke, M.A., Fellow and Tutor) of
_ King’s College, Cambridge
bRAGHIOPODS (RECENT)
By A. E. Saiptey, M.A., Fellow of Christ’s College,
Cambridge |
BRACHIOPODS (FOSSIL)
bye: KR. C. Reep, M.A., Trinity Colleges.Cambridge
New Bork
Mes CV iia NesACN Do CO:
AND LONDON
1895
All rights reserved
«“ Why, you might take to some light study: conchology, now;
I always think that must be a light study.”
GEORGE Exiot, Middlemarch.
CopyRIGHT, 1895,
By MACMILLAN AND CO.
| 2029
Norwood 3Bress :
J. S. Cushing & Co. — Berwick & Smith.
Norwood, Mass., U.S.A.
“ny og
Coo
CL aa
a. oh Uta
PREFACE TO THE MOLLUSCA
THE general plan of classification adopted in this work is not
that of any single authority. It has been thought better to
adopt the views of recognised leading specialists in the various
groups, and thus place before the reader the combined results
of recent investigation. This method may, perhaps, occasion a
certain number of small discrepancies, but it is believed that
the ultimate effect will be to the advantage of the student.
The classification adopted for the recent Cephalopoda is that
of Hoyle (‘ Challenger’ Reports, Zoology, vol. xvi.), for the fossil
Cephalopoda (Nautiloidea) that of Foord (Catalogue of the
Fossil Cephalopoda in the British Museum, 1888-91), and (Am-
monoidea) P. Fischer (Manuel de Conchyliologie, 1887). In
the Gasteropoda the outlines are those adopted by Pelseneer
(Mém. Soe. Malacol. Belg. xxvii. 1894), while the details are
derived, in the main, from P. Fischer. The Amphineura, how-
ever, have not been regarded as a separate class. The grouping
of the Nudibranchiata is that of Bergh (Semper, Reisen im
Archipel der Philippinen, ii. 3). The Pelecypoda are classified
according to Pelseneer’s most recent grouping.
Acknowledgment of the principal sources of information
has been made in footnotes, and a short list of leading author-
ities has been appended to the chapters on anatomy, for the use
of students desirous to pursue the subject further. In the case
V
vi PREFACE
of geographical distribution the authorities are too numerous
and scattered to admit of a list being given.
A special word of thanks is due to Mr. Edwin Wilson for
his patient care in preparing the illustrations, the majority of
which are taken from specimens in the University Museum of
Zoology. Mr. Edgar Smith, besides affording the kind help
which visitors to the British Museum always experience at his
hands, has permitted me to use many specimens for the pur-
poses of illustration.
A. H. COOKE.
Kine’s CoLLEGE, CAMBRIDGE,
20th December 1894.
CONTENTS
ScHEME OF THE CLASSIFICATION ADOPTED IN THIS Boor .
MOLLUSCA
GAA BaAGE RR.
INTRODUCTION — POSITION OF MOLLUSCA IN THE ANIMAL KINGDOM —
CLASSIFICATION — ORIGIN OF LAND AND FRESH-WATER MOLLUSCA
CHAPTER II
Lanp AND FRESH-WATER MOLLUSCA, THEIR HABITS AND GENERAL
Economy : : : : : : : F
CHAPTER UI
ENEMIES OF THE MoLuusca — MEANS OF DEFENCE — MIMICRY AND PRO-
TECTIVE COLORATION — Parasitic Mo.ntiusca — CoMMENSALISM —
VARIATION. eo - - ; ‘ : : : ,
CH ASR Eire LV
Uses oF SHELLS FOR MONEY, ORNAMENT, AND Foop — CULTIVATION OF
THE OysTER, MUSSEL, AND SNAIL — SNAILS AS MEDICINE — PRICES
GIVEN FOR SHELLS : ; ; : : : ; : : é
CECA ER. Vv
REPRODUCTION — DEPOSITION OF EGGS — DEVELOPMENT OF THE FERTIL-
ISED Ovum — DIFFERENCES OF SEX — DIOECIOUS AND HERMAPHRO-
DITE Moititusca — DEVELOPMENT OF FRESH-WATER BIVALVES
Vii
ho
co
On
(op)
96
Vill MOLLUSCA
CHAPTER VI
l-ESPIRATION AND CIRCULATION — THE MANTLE z § ‘ 2 .» 450
CHAPTER VU
OrGANS OF SENSE: ToucH, SicHT, SMELL, HEARING — TuE Foot — THE
NERVOUS SYSTEM . - - ; : - : : ; é ee UE
CHAPTER Vii
Tue DIGESTIVE ORGANS, JAW, AND RapULA: ExcRETORY ORGANS . 209
CHAPTER IX
THE SHELL, ITs Form, CoMposiITION, AND GROWTH — DESIGNATION OF
Irs Various ParTS : ; : : é : : : : . 244
CHAPTER X
GEOGRAPHICAL DISTRIBUTION OF LAND AND FRESH-WATER MOLLUscA —
THE PALAEARCTIC, ORIENTAL, AND AUSTRALASIAN REGIONS . ee
CHAP TER xt
GEOGRAPHICAL DistrRIBUTION oF Lanp Mo.tvusca (continued) — THE
ETHIOPIAN, NEARCTIC, AND NEOTROPICAL REGIONS 328
CHAPTER jat
DISTRIBUTION OF MARINE Mo.utiusca — Deep-sEA MOoLuusca AND THEIR
CHARACTERISTICS . : : P : : : : : 2 . 9360
CHAPTER XII
Crass CEPHALOPODA . : : 5 5 : i x . - » os
CONTENTS 1x
CHAPTER XIV
CxLass GASTEROPODA — AMPHINEURA AND PROSOBRANCHIATA . ; . 400
;
CHAR E iit JV.
Crass GASTEROPODA (continued:): OPISTHOBRANCHIATA AND PULMONATA 427
CHAPTER XVI
CLASSES SCAPHOPODA AND PELECYPODA . 3 : ; 2 ‘ . 444
BRACHIOPODA (RECENT)
CHAPT RRAXV iL
INTRODUCTION — SHELL — Bopy — DiGEsTIvVE System — Bopy Cavity —
CIRCULATORY SYSTEM — EXCRETORY ORGANS — MuscLes — NERVOUS
SysteEM — REPRODUCTIVE SysTEM — EmpryoLtocy — Hasits — Dis-
TRIBUTION — CLASSIFICATION ; : : ; : : ‘ . 4638
BRACHIOPODA (FOSSIL)
CER AP ER, ox Velih
INTRODUCTION — Division I. EcarpINES — EXTERNAL CHARACTERS — IN-
TERNAL CHARACTERS — Division II. TEsTICARDINES — EXTERNAL
CHARACTERS — INTERNAL CHARACTERS — SYNOPSIS OF FAMILIES —
_ STRATIGRAPHICAL DISTRIBUTION — PHYLOGENY AND ONTOGENY . . 491
SCHEME OF THE CLASSIFICATION ADOPTED IN
THIS BOOK
MOLLUSCA
Class Order Sub-order Section
Eee (p. 382).
Beer anche. Phragmophora (p. 386).
ata Sepiophora (p. 588).
EOSIN { Myopsidae (p. 889).
Chondrophora 1 Oi “7d 390
CS igopsidae (p. ):
P
Retrosiphonata (p. 893).
NAUTILOIDEA : ~
Tetra. . Prosiphonata (p. 395).
ranchiata ‘
? Retrosiphonata (p. 397).
AMMONOIDEA 4 Prosiphonata (p. 397).
' POLYPLACOPHORA (p.-400).
Amphineura 4 4 pLacoPHORA (p. 404).
Docoglossa (p. 405).
Zygobranchiata (p.
DiIoTOCARDIA Le 406).
Bhipidoglossa Azygobranchiata (p.
407).
Proso-
prauchiats. Ptenoglossa (p. 411).
. Platypoda (p. 411).
Taeniogloss : ¢
MOonorocARDIA Ann. Mag. Nat. Hist. (2) vi. (1880) p. 68.
38 TENACITY OF LIFE CHAP.
and placing them in tepid water, one of them came out of its
shell, and the next day ate some cabbage leaf. A month or two
afterwards it began repairing the lip of its shell, which was
broken when it was first affixed to the tablet.
While resident in Porto Santo, from 27th April to 4th May
1848, Mr. S. P. Woodward! collected a number of Helices and
sorted them out into separate pill-boxes. On returning home,
these boxes were placed in empty drawers in an insect cabinet,
and on 19th October 1850, nearly two and a half years after-
wards, many of them were found to be still alive. A whole
bagful of H. turricula, collected on the Ilheo de Cima on 24th
April 1849, were all alive at the above-mentioned date.
In September 1858 Mr. Bryce Wright sent? to the British
Museum two specimens of H. desertorum which had been dor-
mant for four years. They were originally collected in Egypt
by a Mr. Vernédi, who, in May 1854, while stopping at one of
the stations in the desert, found a heap of thorn-bushes lying in
a corner of the building, rather thickly studded with the snails.
He picked off fifteen or twenty specimens, which he carried
home and locked up in a drawer, where they remained undis-
turbed until he gave two to Mr. Wright in September 1858.
In June 1855 Dr. Woodward placed specimens of H. candi-
dissima and H. aperta in a glass box, to test their tenacity of
life; he writes of their being still alive in April 1859.
Mr. R. E. C. Stearns records? a case of Buliminus pallidior
and H. Veatchit from Cerros I. living without food from 1859
to March 1865.
H. Aucapitaine mentions‘ a case of H. lactea found in cal-
cinated ground in a part of the Sahara heated to 122° F., where
no rain was said to have fallen for five years. The specimen re-
vived after being enclosed in a bottle for three and a half years.
In August 1863, Mr. W. J. Sterland® put specimens of H.
nemoralis in a box and afterwards placed the box in his cabinet ;
in November 1866 one specimen was discovered to be alive.
Gaskoin relates ® a case in which specimens of H. lactea were
purchased from a dealer in whose drawer they had been for two
1 Ann. Mag. Nat. Hist. (2) vi. p. 489. 2 Thid. (8) iii. p. 448.
3 Amer. Nat. xi. (1877) p. 100; Proc. Calif. Ac. iii. p. 329.
* Gaz. Med. Alger. 1865, 5th Jan. p. 9. 5 Science Gossip, 1867, p. 40.
6 Ann. Mag. Nat. Hist. (2) ix. p. 498.
II AGE OF SNAILS 39
years. This dealer had them from a merchant at Mogador, who
had kept them for more than that time under similar conditions.
One of these shells on being immersed in water revived, and in
April 1849 was placed quite alone under a bell jar with earth
and food. In the end of the following October about thirty
young H. lactea were found crawling on the glass.
Mr. R. D. Darbishire bought! some H. aperta in the market
at Nice on 18th February 1885. Two specimens of these, placed
with wool in a paper box, were alive in December 1888. ‘This
is a very remarkable case, H. aperta not being, like H. deserto-
rum, H. lactea, H. Veatchii and Bul. pallidior, a desert snail, and
therefore not accustomed to fasting at all.
Age of Snails. — It would appear, from the existing evi-
dence, which is not too plentiful, that five years is about the
average age of the common garden snail. Mr. Gain has pub-
lished * some interesting observations on the life of a specimen
from the cradle to the grave, which may be exhibited in a tabu-
lar form.
Aug. 1882. Eggs hatched; one attained diameter of 3 in.
before winter; fed on coltsfoot and cabbage.
oth Oct. 1883. Shell 1 in. in diameter, no lip formed.
July 1884. Shell finished; diameter 1} in., including
perfect lip.
8rd May 1885. Left winter quarters; companion introduced,
with which it was seen in company on oth
August.
9th Aug. “ Laid eggs in soil, which were hatched on
10th September, and feeding on 17th Sep-
tember; in May 1886 the largest of these
was +1 in. diameter.
13th Oct.1887. Old snail died, aged 5 years 2 months.
According to Clessin, the duration of life in Vitrina is one
year, Cyclas 2 years; Hyalinia, Succinea, Limnaea, Planorbis,
and Ancylus are full grown in 2 to 8 years, Helix and Paludina
in 2 to 4, and Anodonta in 12 to 14. Hazay finds? that the
duration of life in Hyalinia is 2 years, in Helix pomatia 6 to 8,
in Helix candicans 2 to 8, in Paludina 8 to 10, in Limnaea and
Planorbis 3 to 4.
1 Journ. of Conch. vi. p. 101. 2 Naturalist, 1889, p. 55.
3 Malak. Blatt. (2) iv. pp. 43 and 221.
40 GROWTH OF THE SHELL CHAP.
Growth of the Shell.— Mr. E. J. Lowe, many years ago,
conducted! some interesting experiments on the growth of
snails. ‘The facts arrived at were —
(1) The shells of Helicidae increase but little for a consider-
able period, never arriving at maturity before the animal has
once become dormant.
(2) Shells do not grow whilst the animal itself remains
dormant.
(8) The growth of shells is very rapid when it does take
place.
(4) Most species bury themselves in the ground to increase
the dimensions of their shells.
Six recently hatched H. pomatia were placed in a box and
regularly fed on lettuce and cabbage leaves from August until
December, when they buried themselves in the soil for winter ;
at this period they had gradually increased in dimensions to the
size of A. hispida. On the 1st April following, the box was
placed in the garden, and on the 3rd the Helices reappeared on
the surface, being no larger in size than they were in December.
Although regularly fed up to 20th June, they were not per-
ceptibly larger, but on that day five of them disappeared, having
buried themselves, with the mouth of the shell downwards, in the
soil. After ten days they reappeared, having in that short time
grown so rapidly as to be equal in size to H. pisana. On the
15th July they again buried themselves, and reappeared on
1st August, having again increased in size. For three months
from this date they did not become perceptibly larger; on 2nd
November food was withheld for the winter and they became
dormant.
A similar experiment, with similar results, was carried on
with a number of H. aspersa, hatched on 20th June. During
the summer they grew but little, buried themselves on 10th
October with the head upwards, and rose to the surface again on
oth April, not having grown during the winter. In May they
buried themselves with the head downwards, and appeared
again in a week double the size; this went on at about fort-
nightly intervals until 18th July, when they were almost fully
grown.
Helix nemoralis, H. virgata, H. caperata, and H. hispida bury
1 Phil. Trans. 1854 (1856), p. 8.
xi SELF-BURIAL OF SNAILS AI
themselves to grow; H. rotundata burrows into decayed wood;
Hyalinia radiatula appears to remain on decaying blades of
grass ; Pupa umbilicata, Clausilia rugosa, and Buliminus obscurus
bury their heads only.
The observations of Mr. W. E. Collinge! do not at all agree
with those of Mr. Lowe, with regard to the mode in which land
Mollusca enlarge their shells. He bred and reared most of the
commoner forms of Helix and also Clausilia rugosa, but never
saw them bury any part of their shell when enlarging it. While
admitting that they may increase their shells when in holes or
burrows of earthworms, he thinks that the process of burying
would seriously interfere with the action of the mantle during
deposition, and in many cases damage the membranaceous film
before the calcareous portion was deposited. Mr. Collinge
has found the following species under the surface in winter:
Arion ater (8-4 in.), Agriolimax agrestis (6-8 in.), Hyalinia
cellaria and HA. alliaria (6-8 in.), Hyalinia glabra (5 in.), Helix
aspersa (O-6 in.), H. rufescens (4-6 in.), H. rotundata (4-5 in.),
Hi. hispida (7 in.), Buliminus obscurus (4-6 in.), B. montanus?
(24 in.), and the following in summer, Hyalinia cellaria and
alliaria (6-8 in.), Helix rotundata (4-5 in.), Balea perversa
(6-8 in.), Cyclostoma elegans (8-4 in.). The same author has
found the following species of fresh-water Mollusca living in
hard dry mud: Sphaerium corneum (8-14 in.), S. rivicola (5-6
in.), S. lacustre (10-14 in.), all the British species of Pis¢diwm
(4-12 in.), Limnaea truncatula (18 in., a single specimen). All
our species of Unio, Anodonta, Bithynia, and Paludina bury
themselves habitually in fine or thick wet mud, to a depth of
from 4 to 14 inches. ©
This burying propensity on the part of Mollusca has been
known to play its part in detecting fraud. When my friend
Mr. E. L. Layard was administering justice in Ceylon, a native
landowner on a small scale complained to him of the conduct of
his neighbour, who had, during his absence from home, diverted
a small watercourse, which ran between their holdings, in such
a way as to filch a certain portion of the land. The offender
had filled up and obliterated the ancient course of the stream,
and protested that it had never run but in its present bed.
1 Naturalist, 1891, p. 75 f.; Conchologist, ii. 1892, p. 29.
2 Taylor, Journ. of Conch. 1888, p. 299.
42 DEPOSITION OF EGGS CHAP.
Mr. Layard promptly had a trench sunk across what was said to
be the old course, and the discovery of numerous living Ampul-
laria, buried in the mud, confirmed the story of one of the
litigants and confounded the other.?
Depositing and Hatching of Eggs: Self-fertilisation. —
There appears to be no doubt that Helices, when once impreg-
nated, can lay successive batches of eggs, and possibly can con-
tinue laying for several years, without a further act of union.
A specimen of Helix aspersa was noticed in company with
another on 5th August; on 9th August it laid eggs in the soil,
and early in the following summer it laid a second batch of eggs,
although its companion had been removed directly after its first
introduction. An Arion received from a distance laid 380 eggs
on dth September, and 70 more on the 28rd of the same month,
although quite isolated during the whole time? By far the
most remarkable case of the kind is related by Gaskoin? A
specimen of Helix lactea was kept in a drawer for about two
years, and then in another drawer for about two years more.
It was then taken out, and placed in water, when it revived,
and was placed alone under a bell jar with earth and food.
Six months after, about 30 young HA. lactea were found
crawling on the glass, the act of oviposition not having been
observed.
The observations of Mr. F. W. Wotton,* with regard to the
fertilisation and egg-laying of Arzon ater, are of extreme inter-
est and value. A pair of this species, kept in captivity, united
on 10th September 1889, the act lasting about 25 minutes.
From that date until the eggs were laid, the animals looked
sickly, dull of colour, with a somewhat dry skin. Eges were
deposited in batches, one, which we will call A, beginning three
days before B. On 10th October A laid 80 eggs; on the 16th,
110; on the 25th, 77; on 8th November, 82; and on 17th
November, 47; making a total of 396. Specimen B, which
began on 13th October, three days after A, made up for the
delay by laying 246 eggs in 40 hours; on 26th October it laid 9,
on 10th November, 121; and on 30th November, 101; a total of
1 See Tennent’s Ceylon, i. p. 221, ed. 5.
2W. A. Gain, Naturalist, 1889, p.55; Brockmeier, Nachr. Deutsch. Malak.
Gesell. xx. p. 118.
3 Ann. Mag. Nat. Hist. (2) ix. p. 498. 4 Journ. Conch. vii. 1893, p. 158 f.
Il HATCHING OF EGGS 43
477. These eggs weighed 624 to the ounce, and, in excluding
the batch of 246, B parted with 2 of its own weight in 40 hours,
while the whole number laid were rather over #? of its own
weight !
While depositing the eggs, the slug remained throughout in
the same position on the surface of the ground, with the head
drawn up underneath the mantle, which was lifted just above
the reproductive orifice. When taken into the hand, it went on
laying eggs without interruption or agitation of any kind. After
it had finished laying it ate half a raw potato and then took a
bath, remaining submerged for more than an hour. Bathing is
a favourite pastime at all periods. Specimens, says Mr. Wotton,
have survived a compulsory bath, with total submersion, of
nearly three days’ duration.
Mr. Wotton’s account of the hatching of the eggs is equally
interesting. It is noticeable that the eggs of one batch do not
hatch by any means simultaneously; several days frequently
intervene. The average period is about 60 days, a damp and
warm situation bringing out the young in 40 days, while cold
and dryness extended the time to 74 days, extremes of any kind
proving fatal. Of the batch of eggs laid by B on 380th Novem-
ber, the first 2 were hatched on the following 16th January,
and 2 more on the 17th; others, from 10 to 20, followed suit
on the succeeding 5 days, until 82 in all were hatched, the
remaining 19 being unproductive.!
By placing the egg on a looking-glass the act of exclusion
can be perfectly observed. For several days the inmate can be
seen in motion, until at last a small crack appears in the surface
of the shell: this gradually enlarges, until the baby slug is able
to crawl out, although it not unfrequently backs into the shell
again, as if unwilling to risk itself in the world. When it once
begins to crawl freely, it buries itself in the ground for 4 or 5
days without food, after which time it emerges, nearly double
its original size. At exclusion, the average length is 9 mm.,
increasing to 56 mm. after the end of 5 months. Full growth
is attained about the middle of the second year, and nearly all
die at the end of this year or the beginning of the next. Death
from exhaustion frequently occurs after parturition. Death
1 T succeeded in hatching out eggs of Helix aspersa, during the very warm
summer of 1893, in 17 days.
44 REPRODUCTION OF LOST PARTS CHAP.
from suffocation is sometimes the result of the formation of
small blisters on the margin of the respiratory aperture. The
attacks of an internal parasite cause death in a singular way.
The upper tentacles swell at the base in such a way as to pre-
vent their extrusion; digestive troubles follow, with rigidity
and loss of moisture, and death ensues in 2 or 5 days.
Mr. Wotton isolated newly-hatched specimens, with the view
of experimenting on their power of self-fertilisation, if the op-
portunity of fertilising and being fertilised by others was denied
them. One of these, after remaining in absolute solitude for
104 months, began to lay, scantily at first (1th January, 2; 25th
January, 2; 11th February, 2), but more abundantly afterwards
(8rd April, 60; 15th and 16th, 70; 29th, 53, etc.), the eggs be-
ing hatched out in 42-48 days. The precautions taken seem to
have been absolutely satisfactory, and the fact of the power of
self-fertilisation appears established as far as Avion ater is con-
cerned.
Braun took young individuals of Limnaea auricularia on the
day they were hatched out, and placed them singly in separate
vessels with differing amounts of water. This was on loth
June 1887. In August 1888 specimen A had only produced a
little spawn, out of which three young were hatched: specimen
B had produced four pieces of spawn of different sizes, all of
which were hatched; specimen C, which happened to be living
with three Planorbis, produced five pieces of spawn distinctly
Limnaeidan, but nothing is recorded of their hatching. Self-
impregnation, therefore, with a fruitful result, appears estab-
lished for this species of Limnaea.!
Reproduction of Lost Parts. — When deprived of their ten-
tacles, eyes, or portions of the foot, Mollusca do not seem to
suffer severely, and generally reproduce the lost parts in a short
time. If, however, one of the ganglia is injured, they perish.
Certain of the Mollusca possess the curious property of being
able to amputate certain parts at will. When Prophysaon, a
species of Californian slug, is annoyed by being handled, an in-
dented line appears at a point about two-thirds of the length
from the head, the line deepens, and eventually the tail is shaken
completely off. Sometimes the Prophysaon only threatens this
spontaneous dismemberment; this line appears (always exactly
1 Nachr. Deutsch. Malak. Gesell. xx. p. 146.
“7 STRENGTH OF SNAILS AS
in the same place), but it thinks better of it, and the indentation
proceeds no further.1 According to Gundlach,? Helix imperator
and H. crenilabris, two large species from Cuba, possess the
same property, which is said to be also characteristic of the sub-
genus Stenopus (W. Indies). Amongst marine species, Harpa
ventricosa and Solen siliqua have been observed to act in a simi-
lar way, Harpa apparently cutting off the end of the foot by
pressure of the shell. Karl Semper, in commenting on the
same property in species of Helicarion from the Philippines
(which whisk their tail up and down with almost convulsive
rapidity, until it drops off), considers? it greatly to the advan-
tage of the mollusc, since any predacious bird which attempted
to seize it, but only secured a fragment of tail, would probably
be discouraged from a second attack, especially as the Helicarion
would meanwhile have had time to conceal itself among the
foliage.
Strength and Muscular Force.— The muscular strength of
snails is surprisingly great. Sandford relates * an experiment on
a Helix aspersa, weighing + 0z. He found it could drag verti-
cally a weight of 24 oz., or nine times its own weight. Another
snail, weighing 4 0z., was able to drag in a horizontal direction
along a smooth table twelve reels of cotton, a pair of scissors, a
screwdriver, a key, and a knife, weighing in all no less than 17
oz., or more than fifty times its own weight. This latter ex-
periment was much the same as asking a man of 12 stone to
pull a load of over 5? tons.
If a snail be placed on a piece of glass and made to crawl, it
will be seen that a series of waves appear to pursue one another
along the under surface of the foot, travelling from back to
front in the direction in which the animal is moving. Simroth
has shown that the sole of the foot is covered with a dense net-
work of muscular fibres, those which run longitudinally being
chiefly instrumental in producing the undulatory motion. By
means of. these muscles the sole is first elongated in front, and
then shortened behind to an equal extent. Thus a snail slides,
not on the ground, but on its own mucus, which it deposits
mechanically, and which serves the purpose of lubricating the
1 Raymond, Nautilus, iv. p. 6.
2 Quoted by Oehlert, Rév. Sc. xxxviil. p. 701.
3 Animal Life, Intern. Scientif. Ser. ed. 1, p. 3895. +4 Zoologist, 1886, p. 491.
46 SUDDEN APPEARANCE AND DISAPPEARANCE CHAP.
ground on which it travels. It has been calculated that an
averaged sized snail of moderate pace progresses at the rate of
about a mile in 16 days 14 hours.!
Sudden Appearance of Mollusca.—It is very remarkable
to notice how suddenly Pulmonata seem to appear in certain
districts where they have not been noticed before. This sudden
appearance is more common in the case of fresh-water than of
land Mollusea, and there can be little doubt that, wherever a
new pond happens to be formed, unless there is something in its
situation or nature which is absolutely hostile to mollusean life,
Mollusea are certain to be found in it sooner or later. ‘Some
23 years ago,” writes Mr. W. Nelson,? “I was in the habit of
collecting shells in a small pond near to the Black Hills, Leeds.
At that time the only molluscan forms found there were a dwarf
form of Sphaerium lacustre, Pisidium pusillum, Planorbis nau-
tileus, and Limnaea peregra. About 10 years ago I resumed my
visits to the locality, and found, in addition to the species already
enumerated, Planorbis corneus. These were the only species
found there until this spring [1883], when, during one of my
frequent visits, I was surprised to find Physa fontinalis and
Planorbis vortex were added to the growing list of species. Later
on Pl. carinatus, Limnaea stagnalis, and Ancylus lacustris turned
up; and during June, P/. contortus was found in this small but
prolific pond.” Limnaea glutinosa is prominent for these re-
markable appearances and disappearances. In 1822 this species
suddenly appeared in some small gravel pits at Bottisham,
Cambs., in such numbers that they might have been scooped
out by handfuls. After that year they did not appear numer-
ous, and after three or four seasons they gradually disappeared.®
Physa (Aplecta) hypnorum is noted in a similar way. In Feb-
ruary 1852, for instance, after a wet month, the water stood in
small puddles about 3 feet by 2 in a particular part of Bottisham
Park which was sometimes a little swampy, though usually quite
dry. One of these puddles was found to contain immense num-
bers of the Aplecta, which up to that time had not been noted as
occurring in Cambridgeshire at all.4 Ina few days the species
entirely disappeared and was never again noticed in the locality.®
1 Thomas, quoted by Jeffreys, Brit. Conch.i.p.30. 2 Journ. of Conch. iv. p. 117.
3 Rey. L. Jenyns, Observations in Nat. Hist. p. 318. 4 Id. ib. p. 319.
5 Further detailed examples will be found in Kew, The dispersal of Shells, pp. 5-26.
rh SHOWERS OF SHELLS 47
Writing to the Zoological Society of London from New
Caledonia, Mr. E. L. Layard remarks:! “The West Indian
species Stenogyra octona has suddenly turned up here in thou-
sands; how introduced, none can tell. They are on a coffee
estate at Kanala on the east coast. I have made inquiries,
and cannot find that the planter ever had seed coffee from the
West Indies. All he planted came from Bombay, and it would
be interesting to find out whether the species has appeared there
also.”
Sometimes a very small event is sufficient to disturb the
natural equilibrium of a locality, and to become the cause either
of the introduction or of the destruction of a species. In 1883
a colony of Helix sericea occupied a portion of a hedge bottom
twenty yards long near Newark. It scarcely occurred outside
this limit, but within it was very plentiful, living in company
with H. nemoralis, H. hortensis, H. hispida, H. rotundata, Hyalinia
cellaria and Hy. nitidula, and Cochlicopa lubrica. In 1888 the
hedge was well trimmed, but the bottom was not touched, and
the next year a long and careful search was required to find
even six specimens of the sericea?
Showers of Shells. — Helix virgata, H. caperata, and Cochli-
cella acuta sometimes occur on downs near our sea-coasts in such
extraordinary profusion, that their sudden appearance out of
their hiding-places at the roots of the herbage after a shower of
rain has led to the belef, amongst credulous people, that they
have actually descended with the rain. There seems, however,
no reason to doubt that Mollusca may be caught up by whil-
winds into the air and subsequently deposited at some consid-
erable distance from their original habitat, in the same way as
frogs and fishes. A very recent instance of such a phenomenon
occurred? at Paderborn, in Westphalia, where, on 9th August
1892, a yellowish cloud suddenly attracted attention from its
colour and the rapidity of its motion. In a few moments it
burst, with thunder and a torrential rain, and immediately after-
wards the pavements were found to be covered with numbers
of Anodonta anatina, all of which had the shell broken by the
violence of the fall. It was clearly established that the shells
1 P. Z. 8. 1888, p. 358. 2W. A. Gain, Naturalist, 1889, p. 58.
3 Das Wetter, Dec. 1892. Another case is recorded in Amer. Nat. ili. p.
556.
48 SINGULAR HABITAT—UNDERGROUND SNAILS CHAP.
could not have been washed into the streets from any adjacent
river or pond, and their true origin was probably indicated
when it was found that the funnel-shaped cloud which burst
over the town had passed across the one piece of water
near Paderborn, which was known to contain the Anodonta in
abundance.
Cases of Singular Habitat. — Mollusca sometimes accus-
tom themselves to living in very strange localities, besides the
extremes of heat and cold mentioned above (pp. 28-24). In
the year 1852, when some large waterpipes in the City Road,
near St. Luke’s Hospital, were being taken up for repairs, they
were found to be inhabited in considerable numbers by Neritina
fluviatilis and a species of Limnaea Dreissensia polymorpha
has been found in a similar situation in Oxford Street, and also
in Hamburg, and has even been known to block the pipes and
cisterns of private houses. In an engine cistern at Burnley,
60 feet above the canal from which the water was pumped
into the cistern, were found the following species: Sphaertum
corneum, S. lacustre; Valvata piscinalis, Bithynia tentaculata ;
Limnaea peregra, very like Suecinea in form and texture;
Planorbis albus, P. corneus, P. nitidus, P. glaber, and thousands
of P. dilatatus, much larger than the forms in the canal below,
a fact probably due to the equable temperature of the water in
the cistern all the year round.? In certain parts of southern
Algeria the fresh-water genera Melania and Melanopsis inhabit
abundantly waters so surcharged with salt that the marine
Cardium edule has actually become extinct from excess of
brine. The common Mytilus edulis is sometimes found within
the branchial chamber and attached to the abdomen of crabs
(Carcinus maenas), which are obliged to carry about a burden
of which they are powerless to rid themselves (see p. 78). A
variety of the common Limnaea peregra lives in the hot water
of some of the geysers of Iceland, and has accordingly been
named geisericola.
Underground Snails. — Not only do many of the land Mol-
lusca aestivate, or hibernate, as the case may be, beneath the
surface of the soil, but a certain number of species live perma-
nently underground, like the mole, and scarcely ever appear
in the light of day. Our own little Caecilianella acicula lives
1 Zoologist, x. p. 3480. 2 Science Gossip, 1888, p. 281.
rt UNDERGROUND AND ROCK-BORING SNAILS 49
habitually from 1 to 38 feet below ground, appearing to prefer
the vicinity of graveyards. Testacella, the carnivorous slug,
scarcely ever appears on the surface during the day, except
when driven by excessive rain, and even then it lurks awhile
under some protecting cover of leafage. There is a curious
little Helix (tristis Pfr.), pecuhar to Corsica, which is of dis-
tinetly subterranean habits. It lives in drifted sand above high-
water mark, always at the roots of Genista Saltzmanni, at a
depth which varies with the temperature and dryness of the
air. In hot and very dry weather it buries itself nearly 2 feet
below the surface, only coming up during rain, and burying
itself again immediately the rain is over. Like a Solen, it often
has a hole above its burrow, by which it communicates with the
air above, so as to avoid being stifled in the sand. The animal,
in spite of its dry habitat, is singularly soft and succulent, and
exudes a very glutinous mucus. It probably descends in its
burrow until it arrives at the humid stratum, the persistence of
which is due to the capillarity of the sand.t. I am assured by
Mr. EK. L. Layard that precisely similar underground habits are
characteristic of Coeliazis Layardi, which lives exclusively in
sand at the roots of scrub and coarse grass at East London.
Rock-boring Snails. — Cases have sometimes been recorded,
from which it would appear that certain species of snails possess
the power of excavating holes in rocks to serve as hiding-places.
At Les Bois des Roches, ten miles from Boulogne, occur a
number of solid calcareous rocks scattered about in the wood.
The sides of the rocks which face N.E. and E. are covered with
multitudes of funnel-shaped holes, 14 inch in diameter at the
opening and contracting suddenly within to } inch. Sometimes
the holes are 6 inches deep, and terminate, after considerable
windings, in a cup-shaped cavity. Helix hortensis inhabits these
holes, and has been observed to excavate them at the rate of
+ inch each hibernation, choosing always the side of the rock
which is sheltered from the prevailing rains. It does not form
an epiphragm, but protrudes part of its body against the rock.
That the snails secrete an acid which acts as a solvent seems
probable from the fact that red litmus paper, on being applied to
the place where the foot has been, becomes stained with violet.?
1 Lecoq, Journ. de Conch. ii. p. 146.
2 Bouchard-Chantereaux, Ann. Sci. Nat. Zool. (4) xvi. (1861) p. 197.
VOL. Il E
50 PRODUCTION OF MUSICAL SOUNDS CHAP.
Helix aspersa is said to excavate holes 10 to 12 cm. deep at
Constantine, and AH. Mazzullit is recorded as perforating lime-
stone at Palermo.? .
Snails as Barometers. — An American writer of more than
thirty years ago? gave his experience of Helices as weather-
prophets. According to him, H. alternata is never seen abroad
except shortly before rain; it then climbs on the bark of trees,
and stations itself on leaves. Helix clausa, H. ligera, H. penn-
sylvanica, and H. elevata climb trees two days before rain, if it
is to be abundant and continuous. MSueccinea does the same, and
its body is yellow before rain and bluish afterit. Several of the
Helices assume a sombre colour after rain, when their bodies
are exceedingly humid; after the humidity has passed off they
resume a clearer and lighter tint.
Production of Musical and other Sounds.— Certain mol-
luses are said to be capable of producing musical sounds. Sir
J. E. Tennent describes his visit to a brackish-water lake at Bat-
ticaloa, in Ceylon, where the fishermen give the name of the
‘crying shell’ to the animal supposed to produce the sounds.
“The sounds,” he says,* “came up from the water like the gen-
tle thrills of a musical chord, or the faint vibrations of a wine-
glass when its rim is rubbed by a moistened finger. It was not
one sustained note, but a multitude of tiny sounds, each clear
and distinct in itself; the sweetest treble mingling with the
lowest bass. On applying the ear to the woodwork of the boat, -
the vibration was greatly increased in volume. The sounds
varied considerably at different points as we moved across the
lake, and occasionally we rowed out of hearing of them alto-
gether.” According to the fishermen, the shells were Pyrazus
palustris and Littorina laevis. It appears uncertain whether the
sounds are really due to Mollusca. Fishermen in other parts of
India assert that the sounds are made by fish, and, like those in
Ceylon, produce the fish which they say ‘sings.’ The same, ora
similar sound, has also been noticed to issue from the water in
certain parts of Chili, and on the northern shores of the Gulf of
1 Forel, Ann. Sci. Nat. (3) xx. p. 576; Bretonniére, Comptes Rendus, cvii.
p. 566.
2 Brit. Mus. Collection.
3 Thomas, quoted by Récluz in Journ. de Conch. vii. 1858, p. 178.
+ Nat. Hist. of Ceylon, p. 382. See also T. L. Taylor, Rep. Brit. Ass. for
1848, p. 82.
wt
“3
na HABITS OF CARNIVOROUS SNAILS AND SLUGS 5!
Mexico. Dendronotus arborescens, when confined in a glass jar
of sea water, has been noticed! to emit a sound like the clink of
a. steel wire. According to Lieut.-Col. Portlock,? F.R.S., Helix
aperta, @ very common species in South Europe, has the property
of emitting sounds when irritated. When at Corfu, he noticed
that if the animal is irritated by a touch with a piece of straw
or other light material, it emits a noise, as if grumbling at
being disturbed. He kept a specimen in his house for a con-
siderable time, which would make this noise whenever it was
touched.
The Rev. H. G. Barnacle describes the musical properties of
Achatinella in the following terms:% *“* When up the mountains
of Oahu I heard the grandest but wildest music, as from hun-
dreds of Aeolian harps, wafted to me on the breezes, and my
companion (a native) told me it came from, as he called them,
the singing shells. It was sublime. I could not believe it, but
a tree close at hand proved it. On it were many of the Acha-
tinella, the animals drawing after them their shells, which grated
against the wood and so caused a sound; the multitude of
sounds produced the fanciful music. On this one tree I took 70
shells of all varieties.”
Habits of the Agnatha. — Not much is known of the habits
and mode of life of the Aynatha, or carnivorous Land Mollusea.
In this country we have only two, or at most three, of this
group, belonging to the genus Testacella, and, in all probability,
not indigenous to our shores. There seems little doubt, when
all the circumstances of their discovery are taken into account,
that both Testacella haliotidea and T. Maugei have been im- |
ported, perhaps from Spain or Portugal in the first instance,
along with roots imbedded in foreign earth, for their earliest
appearances can almost invariably be traced back to the neigh-
bourhood of large nursery grounds, or else to gardens supplied
directly from such establishments.
The underground life of Testacella makes observation of its
habits difficult. It is believed to feed exclusively on earth-
worms, which it pursues in their burrows. Continued wet
weather drives it to the surface, for though loving damp soil it
1 Dr. R. E. Grant, Edinb. Phil. Journ. xiv. p. 188.
2 Rep. Brit. Ass. for 1848, p. 80. The statement is confirmed by Rossmissler.
8 Journ. of Conch. iv. p. 118.
52 HABITS OF CARNIVOROUS SNAILS AND SLUGS CHAP.
is decidedly averse to too much moisture, and under such cir-
cumstances it has even been noticed! in considerable numbers
crawling over a low wall. In the spring and autumn months,
according to Lacaze-Duthiers,? it comes to the surface at night,
hiding itself under stones and débris during the day. Larth-
worms are, at these periods, nearer the surface, and the Testacella
has been seen creeping down into their burrows. The author
has taken 7. Mauget abundantly under clumps of the common
white pink in very wet weather, lying in a sort of open nest in
the moist earth. On the other hand, when the earth is baked
dry by continued drought, they either bury themselves deeper,
sometimes at a depth of 38 feet, in the ground, or else become
encysted in a capsule of hardened mucus to prevent evaporation
from the skin. When first taken from the earth and placed in
a box, the Testacella invariably resents its capture by spitting up
the contents of its stomach in the shape of long fragments of
half-digested worms.
It appears not to bite the worm up before swallowing it, but
contrives, in the most remarkable manner, to take down whole
Fia. 20.— Testacella haliotidea Drap., protruding its pharynx (ph) and radula (7) ;
oe, oesophagus; p.o, pulmonary orifice; sh, shell; ¢, tentacles (after Lacaze-
Duthiers).
worms apparently much too large for its stomach. Mr. Butterell
relates * that, after teasing a specimen of 7. Maugez, and making
it emit a quantity of frothy mucus from the respiratory aperture,
he procured a worm of about three inches long, and rubbed the
worm gently across the head of the Zestacella. The tongue was
rapidly extended, and the victim seized. The odontophore was
then withdrawn, carrying with it the struggling worm, which
made every effort to escape, but in vain; in about five minutes
all had disappeared except the head, which was rejected. This
protrusion of the tongue (radula) and indeed of the whole
1 Zoologist, 1887, p. 29. 2 Arch. Zool. Exp. Gén. (2) v. p. 459 f.
3 Journ. of Conch. iii. p. 277 ; compare W. M. Webb, Zoologist, 1893, p. 281.
II HABITS OF CARNIVOROUS SNAILS AND SLUGS 53
pharynx, is a very remarkable feature in the habits of the ani-
mal. It appears, as it were, to harpoon its prey by a rapid thrust,
and when the victim is once pierced by a few of the powerful
sickle-shaped teeth (compare chap. viii.) it is slowly but surely
drawn into the oesophagus (Fig. 20).
Most gardeners are entirely ignorant of the character of
Testacella, and confuse it, if they happen to notice it at all, with
the common enemies of their tender nurslings. Cases have been
known, however, when an intelligent gardener has kept specimens
on purpose to kill worms in ferneries or conservatories. In some
districts these slugs are very numerous; Lacaze-Duthiers once
dug 182 specimens from a good well-manured piece of ground
whose surface measured only ten square yards.
Towards the end of September or beginning of October the
period of hibernation begins. I infer this from the behaviour of
specimens kept in captivity, which, for about a fortnight before
this time, gorged themselves inordinately on as many worms as I
chose to put into their box, and then suddenly refused food,
buried themselves deeply in the earth, and appeared no more
during the winter. The eggs are apparently much less numerous
than is the case with Limax or Helix, and very large, measuring
about ¢ inch in diameter. They are enveloped in a remarkably
tough and elastic membrane, and, if dropped upon any hard sur-
face, rebound several inches, just like an india-rubber ball.
The animal creeps rather rapidly, and has the power of
elongating its body to a remarkable extent. When placed on
the surface of the ground, in the full light of day, it soon betrays
uneasiness, and endeavours to creep into concealment. Its method
of burying itself is very interesting to watch. It first elongates
its neck and inserts its head into the soil; gradually the body
begins to follow, while the tail tilts upwards into the air. No
surface motion of the skin, no writhing or wriggling motion of
any kind occurs ; the creature simply works its way down in a
stealthy and mysterious way, until at last it is lost to view.
The great Glandina, which attain their maximum develop-
ment in Mexico and the southern United States, are a very
noticeable family in this group. According to Mr. Binney,!
Glandina truncata Gmel., one of the commonest species of the
genus, is somewhat aquatic in its habits. It is found in the sea
1 Bull. Mus. Comp. Zool. Harv. iv. p. 85.
54 HABITS OF CARNIVOROUS SNAILS AND SLUGS CHAP.
islands of Georgia and around the keys and everglades of Florida,
where it attains a maximum length of 4 inches, while in less
humid situations it scarcely measures more than 1 inch. It
occurs most abundantly in the centre of clumps and tussocks of
coarse grass in marshes close to the sea-coast. By the action of
the sharp, sickle-shaped teeth of its radula-the soft parts of its
prey (which consists chiefly of living Helices) are rapidly rasped
away; sometimes they are swallowed whole. It has been known
to attack imax when confined in the same box, rasping off large
pieces of the integument. In one case an individual was noticed
to devour one of its own species, thrusting its long neck into the
interior of the shell, and removing all the viscera.
Fic. 21.— Glandina sowerbyana Pfr. (Strebel).
The Glandinae of southern Europe, although scarcely rival-
ling those of Central America in size or beauty, possess similar
carnivorous propensities. Glandina Poireti has been observed,}
on Veglia Island, attacking a living Cyclostoma elegans. By its
powerful teeth it filed through two or three whorls of the shell
of its victim, and then proceeded to devour it, exactly in the
same manner as a Watica or Buccinum perforates the shell of a
Tellina or Mactra in order to get at its contents.
Few observations appear to have been made on the habits or
food of Streptaxis, Rhytida, Ennea, Daudebardia, Paryphanta,
and other carnivorous Mollusca. , in. in
length, and 4 in. in breadth at
its base (see Fig. 54). 7
It appears most probable that "A “Tiyaiinta exvavatu Bean; By Heli
the dart is employed as an ad- = fortensis Miill.; C, Helix aspersa
junct to the sexual act. Besides fy wie
the fact of the position of the dart sac anatomically, we find
that the darts are extruded and become embedded in the flesh
just before or during the act of copulation. It may be regarded,
then, as an organ whose punctures induce excitement prepara-
tory to sexual union. It only occurs in well-grown specimens.
When once it begins to form, it grows very rapidly, perhaps
not more’ than a week being required for its entire formation.
The dart is almost confined to Helicidae, a certain number
of exceptions being known which border on Helix. Hyalinia
nitida and excavata are the only British species, not Helices,
which are known to possess it. It has not been noticed to
occur in the slugs, except in the N. American genus Tebenno-
phorus. About one-third of the British Helices are destitute of
the dart... H. rufescens possesses a double bilobed sac, but only
two darts, which le in the lower lobes. It does not use the
darts, and could not do so, from the relative sizes of dart and
sac; it has often been watched when uniting, but the use of the
darts has never been observed. From this it has been inferred
that the darts are degenerate weapons of defence, and that they
were in fact at one time much stronger organs and more often
used.2. This theory, however, does not seem consistent with
1C. Ashford, Journ. of Conch. iii. p. 239, iv. pp. 69, 108.
2 W. E. Collinge, Zoologist, 1890, p. 276.
144 HERMAPHRODITE ,MOLLUSCA, GENERATIVE ORGANS _ cuHap.
the whole circumstances of the occurrence, position, and pres-
ent use of the darts.
Hermaphrodite Mollusca. — (6) Digonopora.— As an exam-
ple of the Digonopora or hermaphrodite Mollusca with separate
generative apertures for the male and female organs, we may
take the common Limnaea stagnalis (Fig. 55). It will be seen
from the figure that the relative positions of the hermaphrodite
gland and duct, and of the albumen gland, are the same as in
Helix. When the oviduct parts company from the vas deferens,
it becomes furnished with several accessory glands, one of which
(GLE.) probably serves as a reservoir for the ova, and answers
more or less to a uterus. The tube leading to the spermatheca
Fia. 55.— Genitalia of Limnaea stagnalis
L. (from a dissection by F. B. Stead),
xi.
A.G, albumen gland.
Ac.G, accessory gland.
F.0, female orifice.
G1.E, glandular enlargement.
H.D, hermaphrodite duct.
H.G, hermaphrodite gland.
Li, liver.
M.O, male orifice.
P, penis sac.
Pr, prostate.
R.M, retractor muscle of penis.
Sp, spermatheca.
V.D, vas deferens.
is short, and there is no divergent coecum. The female orifice
lies near to the external opening of the branchial cavity. The
vas deferens, which is very long, is furnished with a large pros-
tate gland. The penis sac is greatly dilated, and there is no
flagellum. The male orifice is behind the right tentacle,
slightly in advance of the female orifice (compare Fig. 102).
Most of the Opisthobranchiata, but not all, have separate
sexual orifices. Numerous variations from the type just de-
V GENITALIA; OF PELECYPODA 145
seribed will be found to occur, particularly in the direction of
the development of accessory glands, which are sometimes very
large, and whose precise purpose has in many cases not been
satisfactorily determined.
Pelecypoda. — In the dioecious Pelecy poda, v which form the
great majority, the reproductive system is simple, and closely
parallel in both sexes. It consists of a pair of gonads, which
are either ovaries or tests, and a pair of oviducts or sperm-ducts
which lead to a genital aperture. The gonads are usually placed
symmetrically at the sides or base of the visceral mass. The
oviduct is short, and the genital aperture is usually within the
branchial chamber, thus securing the fertilisation of the ova by
the spermatozoa, which are carried into the branchial chamber
with the water which passes through the afferent siphon.
Hermaphrodite Pelecypoda are rare, the sexes being usually
separate. The following are assured instances: Pecten glaber,
P. jacobaeus, P. maximus, Ostrea edulis, Cardium norvegicum,
Pisidium pusillum, Cyclas cornea, Pandora rostrata, Aspergilluim
dichotomum, and perhaps Clavagella. The greater number of
these have only a single genital gland (gonad) on each side,
with a single efferent duct from each, but part of the gland is
male and part female, e.g. in the Pectens above mentioned.
Pandoraand Aspergillum have two distinct glands, respectively
male and female, on each side, each of the two glands possessing
its separate duct, and the two ducts from each side eventually
opening near one another. It appears probable that the Septr-
branchiata (Cuspidaria, Poromya, Lyonsiella, etc.) must also be
added to the number of hermaphrodite Pelecypoda which have
separate male and female glands.
It is worthy of remark that all the hermaphrodite Pelecypoda
belong to forms decidedly specialised, while forms distinctly
primitive, such as Nueula, Solenomya, Arca, and Trigonia are all
dioecious. In Gasteropoda similarly, the least specialised forms
(the Amphineura, with the exception of the Meomenzidae, and
the Rhipidoglossa) are dioecious. It is possible therefore that
in the ancestors of the Mollusca the separation of the sexes had
already become the normal type of things, and that herma-
phroditism in the group is, to a certain extent, a sign or accom-
paniment of specialisation.!
1 Pelseneer, Comptes Rendus, cx. p. 1081.
VOL. III 1
146 DEVELOPMENT OF LARVAL PELECYPODA CHAP.
Development of Fresh-water Bivalves. — The vast majority
of fresh-water bivalves either pass the larval stage entirely
within the mother, and do not quit her except in a perfectly
developed form (Cyclas, Pisidium), or assume a mode of de-
velopment in which free larvae indeed occur, but are specially
modified for adaptation to special circumstances (Unio). Cyclas
and Pisidium, and no doubt all the kindred genera, preserve
their ova in a sort of brood-pouch within the gills, in which the
ova pass the earlier stages of their development. But, even so,
the larva of these genera retains some traces of its original free-
swimming habits, for a rudimentary velum, which is quite useless
for its present form of development, has been detected in Cyclas.
The larva of Dreissensia (see Fig. 47, A), so far as is at
present known, stands alone among fresh-water bivalves in being
free-swimming, and to this property has been attributed, no
doubt with perfect justice, the fact of the extraodinarily rapid
spread of Dreissensia over the continent of Europe (chap. xvi.).
In expelling the ova, the parent slightly opens the shells and
then quickly closes them, shooting out a small point of white
slime, which is in fact a little ballof eggs. The general course
of development is precisely parallel to that of marine Pelecypoda,
greatly resembling, so far as form is concerned, certain stages in
the growth of the larvae of Modiolaria and Cardium, as figured
by Lovén.1
In June and July the larvae appear in large numbers on the
surface of the water, when in spite of their exceedingly small
size, they can be captured with a fine hand-net. They pass
about eight days on the surface, feeding apparently on minute
floating algae. During this time, the principal change they
undergo is in the formation of the foot, which first appears as
a small prominence midway between the mouth and anus,
and gradually increases in length and flexibility. When the
larva sinks to the bottom, the velum soon disappears entirely,
the foot becomes exceedingly long and narrow, while the shell
is circular, strongly resembling a very young Cyclas.
Larvae of Unionidae. — The early stages of the develop-
ment of Unio and Anodonta (so far as the species of North
America, Europe, and Asia are concerned) is of extreme interest,
from the remarkable fact that the young live for some time
1 Kon. Vet. Akad. Handl. 1848, pp. 329-455.
Vv GLOCHIDIUM OF ANODONTA 147
parasitically attached to certain species of fresh-water fishes. In
order to secure this attachment, the larva, which is generally
known as Glochidiwm, develops a long filament which perhaps
renders it aware of the neighbourhood of a fish, and also a larval
shell furnished with strong hooks by which it fastens itself to
the body of its unconscious host (Fig. 56). According to some
interesting observations made by Mr. O. H. Latter,! the ova
pass into the external gill of the mother, in which is secreted
a nutritive mucus on which they are sustained until they
arrive at maturity and a suitable opportunity occurs for their
‘being born.’ If this opportunity is deferred, and the Glochidia
mature, their so-called ‘byssus’ becomes developed, and by being
A B
Fic. 56.— A, Glochidium immediately after it is hatched: ad, adductor muscle; by,
‘byssus’ cord; s, sense organs; sh, shell. B, Glochidium after it has been on the
fish for some weeks: a.ad, p.ad, anterior and posterior adductors; a/, alimentary
canal; au.v, auditory vesicle; 67, branchiae; f, foot; mt, mantle. (Balfour.)
entangled in the gill filaments of the parent, prevents their
escaping. It is interesting to notice that, when the nutritive
mucus of the parent is used up, it becomes, as 1t were, the turn
of the children to provide for themselves a secondary mode of
attachment.
The mother Anodonta does not always retain the Glochidium
until fish are in her neighbourhood. Gentle stirring of the
water caused them to emit Glochidium in large masses, if the
movement was not so violent as to cause alarm. The long
slimy masses of Glochidiwm were observed to be drawn back
again within the shell of the mother, even after they had been
ejected to a distance of 2 or 3 inches.
It is a mistake to assert that the young Glochidiwm can
swim. When they finally quit the mother, they sink to the
1 P. Z. §. 1891, p. 52 f.
148 DEVELOPMENT OF GLOCHIDIUM CHAP
bottom, and there remain resting on their dorsal side, with the
valves gaping upwards and the so-called byssus streaming up
into the water above them. ‘There they remain, until a conven-
ient ‘host’ comes within reach, and if no ‘host’ comes within a
certain time, they perish. They are eviden‘ly peculiarly sensitive
to the presence of fish, but whether they perceive them by smell
or some other sense is unknown. ‘“ The tail of a recently killed
stickleback thrust into a watch-glass containing Glochidium
throws them all inte the wildest agitation for a few seconds ;
the valves are violently closed and again opened with astonish-
ing rapidity for 15-25 seconds, and then the animals appear
exhausted and lie placid with widely gaping shells — unless they
chance to have closed upon any object in the water (e.g. another
Glochidium), in which case the valves remain firmly closed.”
In about four weeks after the Glochidium has quitted its host,
and the permanent shell has made its appearance w7thin the two
valves of the Glochidium, the projecting teeth of the latter press
upon the ventral edge of the permanent shell, at a point about
half way in its lengthward measurement, retarding the growth
of the shell at that particular point, and indenting its otherwise
uninterrupted curve with an irregular notch or dent. As growth
proceeds, this dent becomes less and less perceptible on the
ventral margin of the shell itself, but its effects may be detected,
in well-preserved specimens, by the wavy turn in the lines of
growth, especially near the umbones of the young shell.
Mr. Latter found that all species of fish with which he ex-
perimented had a strong dislike to Glochidiwm as an article of
food. Sometimes a fish would taste it “just to try,” but in-
variably spit it out again ina very decided manner. The cause
of unpleasantness seemed not to be the irritation produced in
the mouth of the fish by the attempt of the Glochidiwm to attach
itself, but was more probably due to what the fish considered a
nasty taste or odour in the object of his attentions.
The following works will be found useful for further study
of this portion of the subject : —
F. M. Balfour, Comparative Embryology, vol. i. pp. 186-241.
F, Blochmann, Ueber die Entwickelung von Neritina fluviatilis Mull.: Zeit.
wiss. Zool. xxxvi. (1881), pp. 125-174.
L. Boutan, Recherches sur l’anatomie et le développement de la Fissurelle;
Arch. Zool. exp. gén. (2) iil. suppl. (1885), 173 pp.
Vv LIST OF AUTHORITIES 149
W. K. Brooks, The development of the Squid (Loligo Pealii Les.): Anniv.
Mem. Bost. Soc. Nat. Hist. 1880.
A 7 The development of the oyster: Studies Biol. Lab. Johns
Hopk. Univ. i. (1880), 80 pp.
R. von Erlanger, Zur Entwickelung von Paludina vivipara: Morph. Jahrb.
xvii. (1891), pp. 337-379, 636-680.
a Zur Entwickelung von Bythinia tentaculata: Mitth. Zool.
Stat. Neap. x. (1892), pp. 376-406.
H. Fol, Sur le développement des Ptéropodes: Arch. Zool. exp. gén. iv.
(1875), pp. 1-214.
, Etudes sur le développement des Mollusques. Hétéropodes: ibid.
v. (1876), pp. 105-158.
, Etudes sur le développement des Gastéropodes pulmonés: ibid.
vill. (1880), pp. 103-232.
. Grenacher, Zur Entwickelungsgeschichte der Cephalopoden: Zeit. wiss.
Zool. xxiv. (1874), pp. 419-498.
. Hatschek, Ueber Entwickelungsgeschichte von Teredo: Arb. Zool. Inst.
Univ. Wien, iii. (1881), pp. 1-44.
. Horst, On the development of the European oyster: Quart. Journ. Micr.
Se. xxii. (1882), pp. 339-346.
. Korschelt and K. Heider, Lehrbuch der vergleichenden Entwickelungs-
geschichte der wirbellosen Thiere, Heft iii. (1893), pp. 909-1177 (the
work is in process of translation into English).
A. Kowalewsky, Embryogénie du Chiton polii avec quelques remarques
sur le développement des autres Chitons: Ann. Mus. Hist. Nat. Mars.
Zool. i. (1883), v.
E. Ray Lankester, Contributions to the developmental history of the
Mollusca: Phil. Trans. Roy. Soc. vol. 165 (1875),
pp- 1-31.
is ms Observations on the development of the pond-snail
(Lymnaeus stagnalis), and on the early stages of
other Mollusca: Quart. Journ. Mier. Sc. xiv. (1874),
pp. 365-391.
Observations on the development of the Cephalopoda:
ibid. xv. (1875), pp. 37-47.
W. Patten, The embryology of Patella: Arb. Zool. Inst. Univ. Wien, vi.
(1886), pp. 149-174.
M. Salensky, Etudes sur le développement du Vermet: Arch. Biol. vi.
(1885), pp. 655-759.
L. Vialleton, Recherches sur les premieres phases du développement de la
Seiche (Sepia officinalis): Ann. Se. Nat. Zool. (7) vi. (1888), pp. 165-
280.
S. Watase, Observations on the development of Cephalopods: Stud. Biol.
Lab. Johns Hopk. Univ. iv. (1888), pp. 163-183.
ae Studies on Cephalopods: Journ. Morph. iv. (1891), pp. 247-
294.
E. Ziegler, Die Entwickelung von Cyclas cornea Lam.: Zeit. wiss. Zool.
xli. (1885), pp. 525-569.
ty WD WwW fF
CHAPTER VI
RESPIRATION AND CIRCULATION—THE MANTLE
THE principle of respiration is the same in the Mollusca as
in all other animals. The blood is purified by being brought,
in successive instalments, into contact with pure air or pure
water, the effect of which is to expel the carbonic acid produced
by animal combustion, and to take up fresh supplies of oxygen.
Whether the medium in which a molluse lives be water or air,
the effect of the respiratory action is practically the same.
Broadly speaking, Mollusca whose usual habitat is the water
‘breathe’ water, while those whose usual habitat is the land
‘breathe’ air. But this rule has its exceptions on both sides.
The great majority of the fresh-water Mollusca which are not
provided with an operculum (e.g. Limnaea, Physa, Planorbis),
breathe air, in spite of living in the water. They make periodic
visits to the surface, and take down a bubble of air, return-
ing again for another when it is exhausted. On the other
hand many marine Mollusca which live between tide-marks
(e.g. Patella, Littorina, Purpura, many species of Cerithium,
Planazis, and Nerita) are left out of the water, through the
bi-diurnal recess of the tide, for many hours together. Such
species invariably retain several drops of water in their bran-
chiae, and, aided by the moisture of the air, contrive to support
life until the water returns to them. Some species of Littorina
(e.g. our own L. rudis and many tropical species) live so near
high-water mark that at neap-tides it must frequently happen
that they are untouched by the sea for several weeks together,
while they are frequently exposed to a burning sun, which
beats upon the rocks to which they cling. In this case it ap-
pears that the respiratory organs will perform their functions
150
CHAP. VI MODES OF RESPIRATION ISI
if they can manage to retain an extremely small amount of
moisture.!
_ The important part which the respiratory organs play in the
economy of the Mollusca may be judged from the fact that the
primary subdivision of the Cephalopoda into Dibranchiata and
Tetrabranchiata is based upon the number of branchiae they
possess. Further, the three great divisions of the Gasteropoda
have been named from the position or character of the breathing
apparatus, viz. Prosobranchiata, Opisthobranchiata and Pul-
monata, while the name Pelecypoda has hardly yet dispossessed
Lamellibranchiata, the more familiar name of the bivalves.
Respiration may be conducted by means of — (a) Branchiae
or Gills, (6) a Lung or Lung-cavity, (¢) the outer skin.
In the Pelecypoda, Cephalopoda, Scaphopoda, and the great
majority of the Gasteropoda, respiration is by means of branchiae,
also known as ctenidia,? when they represent the primitive Mol-
luscan gill and are not ‘ secondary’ branchiae (pp. 156, 159).
In all non-operculate land and fresh-water Mollusca, in the
Auriculidae, and in one aberrant operculate (Amphibola), res-
piration is conducted by means of a lung-cavity, or rarely by a
true lung, whence the name Pulmonata. The land operculates
(Cyclophoridae, Cyclostomatidae, Aciculidae, and Helicinidae)
also breathe air, but are not classified as Pulmonata, since other
points in their organisation relate them more closely to the
marine Prosobranchiata. Both methods of respiration are united
in Ampullaria, which breathes indifferently air through a long
siphon which it can elevate above the surface of the water, and
water througha branchia (see p. 158). Siphonaria (Fig. 57) is
also furnished with a lung-cavity as well as a branchia. Both
these genera may be regarded as in process of change from an
aqueous to a terrestrial life, and in Siphonaria the branchia is to
a great extent atrophied, since the animal is out of the water, on
the average, twenty-two hours out of the twenty-four. In the
allied genus Gadinia, where there is no trace of a branchia, but
1 The result of some experiments by Professor Herdman upon Littorina
rudis, tends to show that it can live much better in air than in water, and goes
far to support the view that the species may be undergoing, as we know many
species must have undergone (see p. 20), a transition from a marine to a terres-
trial life. It was found that marked specimens upon the rocks did not move
their position for thirty-one successive days (Proc. Liverp. Biol. Soc. iv. 1890,
p. 50).
- Diminutive of xreis, a comb.
[152 RESPIRATION BY THE SKIN CHAP.
only a lung-cavity, and in Cerithidea obtusa, which has a pul-
Fia. 57.— A, Siphonaria gigas
Sowb., Panama, the animal
contracted in spirit: g7,
siphonal groove on right
side. B, Gadinia peru-
viana, Sowb., Chili, shell
only: gr, mark of siphonal
groove to right of head.
monary organisation exactly analogous to that of Cyclophorus,
this process may be regarded as practically completed.
Respiration by means of the skin, without the development
Sara.
Qe
Fiac.58.— Aeolis despecta Johnst., British
coasts. (After Alder and Hancock.)
of any special organ, is the
simplest method of breathing
which occurs in the Mollusca.
In certain cases, e.g. Hlysia, Ln-
mapontia, and Cenia among the
Nudibranchs, and the parasitic
Entoconcha and Entocolaz, none
of which possess breathing organs
of any kind, the whole outer
surface of the body appears to
perform respiratory functions. In
others, the dorsal surface is cov-
ered with papillae of varied size
and number, which communicate
with the heart by an elaborate
system of veins. This is the case
with the greater number of the
Aeolididae (Fig. 58, compare Fig.
o, C), but it is curious that when
Q\ the animal is entirely deprived of
these papillae, respiration appears
to be carried on without inter-
ruption through the skin.
In the development of a distinct breathing organ, it would
seem as if progress had been made along two definite linés, each
1 Stoliczka, quoted in Journ. de Conch. xviii. p. 452.
VI DEVELOPMENT OF A BREATHING ORGAN 153
resulting in the exposure of a larger length of veins, 7.e. of a
larger amount of blood, to the simultaneous operation of fresh
air or fresh water. Either (a) the skin itself may have devel-
oped, at more or less regular intervals, elevations, or folds, which
gradually took the form of papillae, or else (6) an inward fold-
ing, or ‘invagination,’ of the skin, or such a modification of the
mantle-fold as is described below (p. 172) may have taken place,
resulting in the formation of a cavity more or less surrounded
by walls, within which the breathing organs were ultimately
developed. Sometimes a combination of both processes seems
to have occurred, and after a papiliform organ has been pro-
duced, an extension or prolongation of the skin has taken place,
in order to afford a protection to it. Respiration by means of a
luneg-cavity is certainly subsequent, in point of time, to respira-
tion by means of branchiae. |
The branchiae seem to have been originally paired, and
arranged symmetrically on opposite sides of the body. It is not
easy to decide whether the multiple form of branchia which
occurs in Chiton (Fig. 59), or the simple form as in Fssurella
* \ y
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i.
‘
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i
i
it
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Fic. 60.— Fissurella virescens Sowb.,
Panama, showing position of the
Fie. 59.— Chiton squamosus L., Bermuda: branchiae: Br, branchiae; E, E, eyes;
A, anus; Br, branchiae; M, mouth. F, foot; M, mantle; T, T, tentacles.
(Fig. 60), is the more primitive. Some authorities hold that the
multiple branchia has gradually coalesced into the simple, others
that the simple form has grown, by serial repetition, into the
multiple. There appears to be no trace of any intermediate
forms, and, as a matter of fact, the multiple branchia is found
154 BREATHING ORGANS IN AMPHINEURA CHAP.
only in the Amphineura, while one or rarely two (never more)
pairs of branchiae, occur, with various important modifications,
in the vast majority of the Mollusca.
Amphineura. — In Chiton the branchiae are external, forming
a long row of short plumes, placed symmetrically along each side
of the foot. The number of plumes, at the base of each of which
lies an osphradial patch, varies from about 70 to as few as 6 or
7. When the plumes are few, they are confined to the pos-
terior end, and thus approximate to the form and position of
the branchiae in the other Amphineura. In Chaetoderma, the
branchiae consist of two small feather-shaped bodies, placed
symmetrically on either side of the anus, which opens into a sort
of cloaca within which the branchiae are situated. In Meomenia
the branchiae are still further degraded, consisting of a single
br
Fic. 61.— Terminal portions of the Amphineura, illustrating the gradual degradation
of the branchiae, and their grouping round the anus in that class. A, Chiton
(Hemiarthrum) setulosus Carp., Torres Str.; B, Chiton (Leptochiton) benthus
Hadd., Torres Str.; C, Chaetoderma; D, Neomenia; a, anus; br, br, branchiae ;
k,k, kidneys ; p, pericardium. (A and B after Haddon, C and D after Hubrecht.)
bunch of filaments lying within the cloaca, while in Proneomenia
there is no more than a few irregular folds on the cloaca-wall
(Fig. 61).
In the Prosobranchiata, symmetrically paired branchiae
occur only in the Fissurellidae, Haliotidae, and Pleurotoma-
riidae, in the former of which two perfectly equal branchiae
are situated on either side of the back of the neck. These
three families taken together form the group known as Zygo-
branchiata In all other families the asymmetry of the body
has probably caused one of the branchiae, the right (originally
left), to become aborted, and consequently there is only one
branchia, the left, in the vast majority of marine Prosobran-
| Gyov, a yoke, from the symmetrical position of the branchiae.
VI BREATHING ORGANS IN PROSOBRANCHIATA 155
chiata, which have been accordingly grouped as Azygobranchiata.
Even in Haliotis the right branchia is rather smaller than the
left, while the great size of the attachment muscle causes the
whole branchial cavity to become pushed over towards the left
side. In those forms which in other respects most nearly
approach the Zygobranchiata, namely, the Trochidae, Neritidae,
and Turbinidae, the branchia has two rows of filaments, one on
each side of the long axis, while in all other Prosobranchiata
there is but one row (see Fig. 79, p. 169).
In the great majority of marine Prosobranchiata the branchia
is securely concealed within a chamber or pouch (the respira-
tory cavity), which is placed on the left dorsal side of the
animal, generally near the back of the neck. For breathing
purposes, water has to be conveyed into this chamber, and
again expelled after it has passed over the branchia. In the
majority of the vegetable-feeding
molluscs (e.g. Littorina, Cerithium,
Trochus) water is carried into the
chamber by a simple prolongation
of one of the lobes or lappets of
the mantle, and makes its exit by
the same way, the incoming and
outgoing currents being separated
by a valve-like fringe depending
from the lobe. In the carnivorous
molluses, on the other hand, a
regular tube, the branchial siphon,
which is more or less closed, has
been developed from a fold of the
mantle surface, for the special pur-
Pes of conducting water to the Fic. 62. — Bullia laevissima Gmel.,
branchia. After performing its showing branchial siphon §;
purpose there, the spent water does nek i en De
not return through the siphon, but cles. (After Quoy and Gaimard.)
is conducted towards the anus by
vibratile cilia situated on the branchiae themselves. In a.large
number of cases, this siphon is protected throughout its entire
length by a special prolongation of the shell called the canai.
Sometimes, as in Buceinum and Purpura, this canal is little
more than a mere notch in the ‘mouth’ of the shell, but in
156 BREATHING ORGANS IN PROSOBRANCHIATA CHAP.
many of the Muricidae (e.g. MW. haustellum, tenuispina, tribulus)
the canal becomes several inches long, and is set with formi-
dable spines (see Fig. 164, p. 256). In Doliwm and Cassis the
canal is very short, but the siphon is very long, and is reflected
back over the shell.
The presence or absence of this siphonal notch or canal
forms a fairly accurate indication of the carnivorous or vege-
tarian tendencies of most marine Prosobranchiata, which have
been, on this basis, subdivided into Stphonostomata and Holosto-
mata. But this classification is of no particular value, and is
seriously weakened by the fact that Matica, which is markedly
‘holostomatous,’ is very carnivorous, while Cerithiwm, which has
a distinct siphonal notch, is of vegetarian tendencies.
In the Zygobranchiata the water, after having aerated the
blood in the branchiae, usually escapes by a special hole or holes
in the shell, situated either at the apex (Fissurella) or along
the side of the last whorl (Haliotis). In Pleurotomaria the sht
answers a similar purpose, serving as a sluice for the ejection of
the spent water, and thus preventing the inward current from
becoming polluted before it reaches the branchiae (see Fig.
79, p.-200).
In Patella the breathing arrangements are very remarkable.
In spite of their apparent external similarity, this genus pos-
sesses no such symmetrically paired plume-shaped branchiae as
Fissurella, but we notice a circlet of gill-lamellae, which extends
completely round the edge of the mantle. It has been shown
by various authorities that these lamellae are in no sense mot-
phologically related to the paired branchiae in other Mollusca,
but only correspond to them functionally. The typical paired
branchiae, as has been shown by Spengel, exist in Patella in
a most rudimentary form, being reduced to a pair of minute
yellow bodies on the right and left sides of the back of the
‘neck.’ longations of the integument, and tentacular
Pe etek os, PHOCeBReS in the neighbourhood of, or surround-
seizing its prey, Ng the branchiae (see Figs. 58 and 84), or
ae ety es even projecting from the whole upper surface
(Strebel.) of the body (Fig. 5, C).
In the Pelecypoda, the chief organs of
touch are the foot, which is always remarkably sensitive, espe-
cially towards its point, the labial palps on each side of the
mouth, and the siphons. In certain cases the mantle border is
prolonged into a series of threads or filaments. These are par-
ticularly noticeable in Pecten, Lepton, and Lima (Fig. 85), the
mantle lobes of the common ZL. hians of our own coasts being
very numerous, and of a bright orange colour. In many genera
—e.g. Unio, Mactra —this sensibility to touch appears to be
shared by the whole mantle border, although it is not furnished
with any special fringing. The ‘arms’ of the Cephalopoda
Vil TASTE IN SNAILS 179
appear to be keenly sensitive to touch, and this is particularly
the case with the front or tentacular pair of arms, which seem
Fic. 84. —Idalia Leachii A. and H., British seas; bv, branchiae. (After
Alder and Hancock.)
to be employed in an especial degree for exploration and inves-
tigation of strange objects.
Taste. — The sense of taste is no doubt present, to a greater
or less extent, in all the head-bearing Mollusca. In many of
these a special nerve or nerves has
pharynx, connecting with the cerebral
ganglion; this no doubt indicates the
seat of the faculty of taste. The Mol-
lusca vary greatly in their hkings for
different kinds of food. Some seem
to prefer decaying and highly odorifer-
ous animal matter (Buccinum, Nassa),
others apparently confine themselves
to fresh meat (Purpura, Natica, Testa-
cella), others again, although naturally
vegetarian, will not refuse flesh on
occasion (Limax, Helix).
Mr. W. A. Gain! has made some
been discovered in the
Fia. 85. — Lima squamosa Lam.,
Naples, showing tentacular
lobes of mantle (f, ¢); a, anus;
ad.m, adductor muscle ; b7,)7,
branchiae; /, foot; sh, shell.
interesting experiments on the taste of British land Mollusca,
as evidenced by the acceptance or rejection of various kinds of
food. He kept twelve species of Arion and Limaz, and eight spe-
cies of Helix in captivity for many months, and tried them with
no less than 197 different kinds of food, cannibalism included.
1 Journ. of Conch. vi. p. 349 ff.
180 POSITION OF THE EYES CHAP.
Some curious points came out in his table of results. Amalia
gagates appears to be surprisingly omnivorous, for out of 197
kinds of food it ate all but 25; Arion ater came next, eating all
but 40. Limazx arborum, on the other hand, was dainty to a
fault, eating only seven kinds of food, and actually refusing
Swedes, which every other species took with some avidity. Cer-
tain food was rejected by all alike, e.g. London Pride, Dog Rose,
Beech and Chestnut leaves, Spruce Fir, Common Rush, Liver-
wort, and Lichens; while all, or nearly all, ate greedily of Pota-
toes, Turnips, Swedes, Lettuces, Leeks, Strawberries, Boletus
edulis, and common grasses. Few of our common weeds or
hedgerow flowers were altogether rejected. Arion and Limax
were decidedly less particular in their food than Helix, nearly
all of them eating earth-worms and puff-balls, which no Helix
would touch. Arion ater and Limax maximus ate the slime off
one another, and portions of skin. Cyelostoma elegans and
Hyalinia nitida preferred moist dead leaves to anything else.
II. Sight
Position of Eyes.—In the majority of the head-bearing
Mollusea the eyes are two in number, and are placed on, or in
the immediate neighbourhood of the head. Sometimes they are
carried on projecting tentacles or ‘ommatophores,’ which are
either simple (as in Prosobranchiata) or capable of retraction
Fia. 86.— A, Limnaea peregra Miill.; e, e, eyes; t, t, tentacles; B, Helix nemoralis
Miill.; e, e, eyes; ¢, ¢, tentacles; p.o, pulmonary orifice.
like the fingers of a glove (Heliz, etc.). Sometimes, as in a large
number of the marine Gasteropoda, the eyes are at the outer
base of the cephalic tentacles, or are mounted on the tentacles
themselves, but never at the tip (compare Fig. 60, p. 153 and
VII ORGANISATION OF THE EYE 18I
Fig. 98, p. 199). In other cases they are placed somewhat
farther back, at the sides of the neck. The Pulmonata are
usually subdivided into two great groups, Stylommatophora and
Basommatophora (Fig. 86), according as the eyes are carried on
the tip of the large tentacles (Helix, and all non-operculate
land shells), or placed at the inner side of their base (Limnaea,
Physa, etc.). In land and fresh-water operculates, the eyes are
situated at the outer base of the tentacles.
In the Helicidae, careful observation will show that the eyes
are not placed exactly in the centre of the end of the tentacle,
but on its upper side, inclining slightly outwards. The eye is
probably pushed on one side, as it were, by the development of
the neighbouring olfactory bulb. The sense of smell being far
more important to these animals than the sense of sight, the
former sense develops at the expense of the latter.
Organisation of the Molluscan Eye. — The eye in Mollusca
exhibits almost every imaginable form,
from the extremely simple to the elab-
orately complex. It may be, as in cer-
tain bivalves, no more than a pigmented
spot on the mantle, or it may consist,
as in some of the Cephalopoda, of a
cornea, a sclerotic, a choroid, an iris,
a lens, an aqueous and vitreous humour,
a retina, and an optic nerve, or of some
of these parts only.
In most land and fresh-water Mol-
lusca the eye may be regarded, roughly
speaking, as a ball connected by an
exceedingly fine thread (the optic nerve) ye. 97, — Eye of Helix poma-
with a nerve centre (the cerebral gang- tia L., retracted within the
lion). In Paludina this ball is elliptic, ca are er. ae
in Planorbis and Neritina it is drawn _ op.n, optic nerve; 7, ret-
out at the back into a conical or pear (After Simroth.)
shape. In Helix (Fig. 87) there is a structureless membrane,
surrounding the whole eye, a lens, and a retina, the latter con-
sisting of a nervous layer, a cellular layer, and a layer of rods
containing pigment, this innermost layer (that nearest the lens)
being of the thickness of half the whole retina.
Comparing the eyes of different Gasteropoda together, we
182 STAGES OF DEVELOPMENT IN THE EYE CHAP.
find that they represent stages in a general course of develop-
ment. Thus in Patella the eye is scarcely more than an invagi-
nation or depression in the integument, which is lined with
pigmented and retinal cells. The next upward stage occurs
in Trochus, where the depression becomes deeper and bladder-
shaped, and is filled with a gelatinous or crystalline mass, but
still is open at the top, and therefore permits the eye to be
Fic. 88. — Eyes of Gasteropoda, showing arrest of development at successive stages:
A, Patella; B, Trochus; C, Turbo; D, Murex ; ep, epidermis; /, lens; op.n, optic
nerve; 7, retina; v.A, vitreous humour. (After Hilger.)
bathed in water. Then, as in Yurbo, the bladder becomes closed
by a thin epithelal layer, which finally, as in some Murez, be-
comes much thicker, while the ‘ eyeball’ encloses a lens (Fig. 88),
which probably corresponds with the ‘ vitreous humour’ of other
types.
In Nautilus the eye is of a very simple type. It consists of
a cup-shaped depression, with a small opening which is not
quite closed by the integument. The retina consists of cells
VII EYE OF CEPHALOPODA 183
which line the interior of the depression, and which communicate
directly with the branches of the optic nerve, there being no
iris or lens. This type of eye,
it will be observed, corresponds
exactly with that which occurs
in Patella. It appears also to
correspond to a stage in the
rs e mo USPNILEALIRA AN \
development of eyes in the Di- Sea
B 3S eee
branchiata (e.g. Octopus, Sepia,
Loligo). WUankester has shown !
that in Loligo the eye first ap-
pears as a ridge, enclosing an
oval area in the integument.
By degrees the walls of this
area close in, and eventually
join, enclosing the retinal cells
within the chamber in which
the lens is afterwards developed sige nee rato. ae ee
(Fig. 89). It thus appears that enclosing p.0.€, primitive optic cham-
in some cases the development Di 0" orice betwoon tho closing
of the eye is arrested at a point Gb. Ci, ciliary body; 7, rudimentary
which in other cases only forms _*°"** # "tina. (Alter Lankester. )
a temporary stage towards a higher type of organisation.
The developed eye in the dibranchiate Cephalopods consists
of a transparent cornea, which may or may not be closed over
Fic. 90.—Eye in
A, Loligo; B, He-
liecor Limax.--C,
Nautilus: a.o.e,
anterior optic
chamber; c, cor-
nea; int, integu-
ment; 27, iris; >
Wy T ‘ NS \
WV \\\\ g Y \
4 aoe
B\\\i “Ve \. \
Ps
| a —<—— 30
| SS";
4 ~
PET eg aRee ot ceaett
gnu oe Se
Ere
Wt
\\\\
I} ||
Fic. 106.— Nervous system of Cardium edule L.: a.m, anterior adductor muscle; br,
branchiae; b7.n, branchial nerve; c.g, c.g, cerebral ganglia; c.p.c, cerebro-pedal
commissure; ¢.v.c', cerebro-visceral commissure; c.v.c, cerebro-visceral commis-
sure of mantle; l.p, labial palps: 7, mouth; p.g, pedal ganglion; p.m, posterior
adductor muscle; v.g, visceral ganglion. (After Drost, x 3.)
can be detected. The pedal ganglion becomes separated into
two portions, one of which innervates the arms, the other the
funnel. Two peculiar gangla (the stellate ganglia) supply a
number of branching nerves to the mantle.
E.L. Bouvier, Systéme nerveux, morphologie générale et classification des
Gastéropodes prosobranches: Ann. Se. Nat. Zool. (7), ii. 1887, pp.
1-510.
J. Brock, Zur Neurologie der Prosobranchier: Zeit. wiss. Zool. xlviii. 1889,
pp. 67-85.
O. Butschli, Bemerkungen iiber die wahrscheinliche Herleitung der Asym-
metrie der Gasteropoda, ete.: Morph. Jahrb. xii. 1886, pp. 202-222.
B. Haller, Zur Kenntniss der Muriciden. I. Anatomie des Nervensystems:
Denksch. Math. Nat. K]. Ak. Wien, xlv. 1882, pp. 87-106.
Untersuchungen tiber marine Rhipidoglossen. II. Textur des
Centralnervensystems und seiner Hiillen: Morph. Jahrb. xi.
1885, pp. 319-436.
”
208 AUTHORITIES CHAP. VII
H. Grenacher, Abhandlungen zur vergleichenden Anatomie des Auges: Abh.
Naturf. Gesell. Halle, xvi. 1884, pp. 207-256 ; xvii. 1886, pp. 1-64.
A. P. Henchman, The Origin and Development of the Central Nervous
System in Limax maximus: Bull. Mus. C. Z. Harv. xx. 1890, pp.
169-208.
V. Hensen, Ueber das Auge einiger Cephalophoren: Zeit. wiss. Zool. xv.
1865, pp. 157-242.
C. Hilger, Beitrige zur Kenntniss des Gasteropodenauges: Morph. Jahrb. x.
1885, pp. 352-371.
Lacaze-Duthiers, Otocystes ou Capsules auditives des Mollusques (Gastéro-
podes): Arch. Zool. Exp. Gén. i. 1872, pp. 97-166.
Du systéme nerveux des Mollusques gastéropodes pulmonés
aquatiques: ibid. pp. 437-500.
P. Pelseneer, Recherches sur le systéme nerveux des Ptéropodes: Arch.
Biol. vii. 1887, pp. 93-130.
Sur la valeur morphologique des bras et la composition du
systéme nerveux central des Cephalopodes: Arch. Biol.
vill. 1888, pp. 723-756.
H. Simroth, Ueber die Sinneswerkzeuge unserer einheimische Weichthiere :
Zeit. wiss. Zool. xxvi. 1876, pp. 227-548.
J. W. Spengel, Die Geruchsorgane und das Nervensystem der Mollusken :
Zeit. wiss. Zool. xxxy. 1881, pp. 333-383.
39 99
CHAPTER VIII
THE DIGESTIVE ORGANS, JAW, AND RADULA: EXCRETORY
ORGANS
THE digestive tract, or, as it is often termed, the alimentary
canal or gut, is a very important feature of the Mollusca. It
may be regarded as consisting of the following parts: (1) a
mouth or oral aperture; (2) a throat or pharynx ; (8) an oesoph-
agus, leading into (4) a stomach, (6) an intestine and rectum,
ending in (6) an anus.
The primitive positions of mouth and anus were presumably
at the anterior and posterior ends of the animal, as in the
Amphineura and symmetrical Mollusca generally. But the
modifications of original molluscan symmetry, which have
already been referred to (p. 164, compare pp. 245, 246), have
resulted in the anus becoming, in the great majority of Gastero-
poda, twisted forward, and occupying a position on some point
in the right side in dextral, and in the left in sinistral species.
The process of digestion, as the food passes from one end of
the tract to the other, is performed by the aid of the secretions
of various glands, which open into the alimentary canal at
different points in its course. The principal of these are the
salivary glands, situated on the pharynx and oesophagus, and
the liver, biliary or hepatic gland, connecting with the stomach.
With these may be considered the anal and ink-glands, which, in
certain genera, connect with the terminal portion of the rectum.
1. The mouth is generally, as in the common snail and peri-
winkle, placed on the lower part of the head, and may be either
a mere aperture, circular or semicircular, in the head-mass, or, as
is more usual, may be carried on a blunt snout (compare Fig. 6,
p. 10, and Fig. 68, p. 159), which is capable of varying degrees
of protrusion. From the retractile snout has doubtless been
VOL, Ill 209 P
210 THE PROBOSCIS, PHARYNX, AND JAWS CHAP.
derived the long proboscis which is so prominent a feature of
many genera (compare Figs. 1, B, and 99), and in some (e.g.
Mitra, Dolium) attains a length exceeding that of the whole
body. Asa rule, Mollusca provided with a proboscis are carniv-
orous, while those whose mouth is on the surface of the head
are vegetable feeders, but this rule is by no means invariable.
The mouth is thickened round the aperture into ‘ lips,’ which are
-often extensile, and appear capable of closing upon and grasping
the food. In the Pelecypoda the mouth is furnished, on each
side, with a pair of special external lobes, the ‘labial palps,’
which appear to be of a highly sensitive nature, and whose
object it is to collect, and possibly to taste, the food before it
passes into the mouth.
2. The Pharynz, Jaws, ant Radula.— Immediately behind
the lips the mouth opens into the muscular throat, pharynx, or
buccal mass. The pharynx of the Glossophora, 7.e. of the Gas-
teropoda, Scaphopoda, and Cephalopoda, is distinguished from
that of the Pelecypoda,! by the possession of two very charac-
teristic organs for the rasping or trituration of food before it
reaches the oesophagus and stomach. ‘These are (a) the jaw or
jaws, and (6) the radula,* odontophore, or lingual ribbon. The
jaws bite the food, the radula tears it up small before it passes
into the stomach to undergo digestion. The jaws are not set
with teeth like our own; roughly speaking, the best idea of the
relations of the molluscan jaw and radula may be obtained by
imagining our own teeth removed from our jaws and set in
parallel rows along a greatly prolonged tongue.®
In nearly all land Pulmonata the jaw is single, and is placed
behind the upper ip. If a common Helix aspersa be observed
crawling up the inside of a glass jar, or feeding on some succu-
lent leaf, the position and action of the jaw can be readily dis-
cerned. It shows very black when the creature opens its mouth,
and under its operation the edge of a lettuce leaf shows a regular
series of little curved indentations, in shape not unlike the semi-
1 There is practically no pharynx in the Pelecypoda, the mouth opening
directly into the oesophagus.
2 Radere, to scrape; ddovs, tooth; Péperv, to carry.
3 The mechanism of the radula has been dealt with by Geddes, Trans. Zool.
Soc. x. p. 485. Riicker has observed (Ber. Oberhess. Gesell. Nat. Heilk. xxii.
p. 207) that the radula in Helix pomatia is the product of five rows of cells; the
use of the first row is uncertain, the second forms the membrane of the radula,
while rows three to five originate the teeth.
VI THE JAW IN PULMONATA PAI |
circular bites inflicted by a schoolboy upon his bread and butter.
The jaw of Helix (Fig. 107, B) is arched in shape, and is
strengthened by a number of projecting vertical ribs. That of
Limaz (A) is straighter, and is slightly striated, without vertical
ribs. In Bulimulus (C) the arch of the Jaw is very conspicuous,
and the upper edges are always denticulated: in Orthalicus there
is a central triangular plate with a number of overlapping plates
on either side; in Succinea (I) there is a large square accessory
plate above the jaw proper. The form of the jaw is peculiar not
Fig. 107.— Jaws of
various Pulmon-
ata: A, Limaz
(gagates Drap.,
Lancashire, 15);
B, Helix (acutis-
sima Lam., Ja-
maica, x 15); C,
Bulimulus (de-
pictus Reeve,
Venezuela, x 20);
Py CALC TOE 2 10.0
(fulica Fér., Mau-
ritius, <7); E,
Succinea (elegans
Riss., Aral Dis-
triGte x oO). FB;
Limnaea (stag-
nalis L., Cam-
bridge, x 30).
only to the genus but to the species as well. Thus the jaw of
H. aspersa is specifically distinct from that of H. pomatia, and
that of H. nemoralis is distinct from both. Wiegmann has
observed! that in young Arion, Limar, and Helix, the jaw con-
sists of two pieces, which coalesce by fusion in the adult, thus
indicating a stage of development in advance of the double jaw
which is found in most of the non-pulmonate Mollusca. In all
fresh-water Pulmonata there are two small accessory side plates.
besides the jaw proper (Fig. 107, F). |
Nearly all the non-carnivorous Prosobranchiata, land, fresh-
water, and marine alike, are provided with two large lateral jaws.
1 Jahrb. Deut. Malak. Gesell. iii. p. 193.
aie aA LN PROSOBRANCHIATA AND OPISTHOBRANCHIATA CH.
Many of these are sculptured with the most elaborate patterns,
and appear to be furnished with raised teeth, like a file. In the
FE
i,
KP
LL
dy
Fic. 108. —Jawsof A, Triton australis Lam., Sydney; B, Ampullaria fasciata Reeve,
Demerara; C, Calliostoma punctulatun Mart., New Zealand; D, Cyclophorus
atramentarius Sowb., Sanghir; all x 15.
Fic. 109. — Jaws of A, Chromodoris gracilis Iher., x 15; B, Scyllea pelagica L., x 7;
C, Pleurobranchus plumula Mont., x 10; D, Pleurobranchaea Meckelii Lam., x 3.
Nudibranchiata the jaws are of great size and beauty of orna-
mentation (Fig. 109).
VIII THE RADULA 213
The carnivorous genera, whether marine (e.g. Conus, Murez,
Buccinum, Nassa) or land (e.g. Testacella, Glundina, Streptavis,
Ennea), are entirely destitute of jaws, the reason probably being
that in all these cases the teeth of the radula are sufficiently
powerful to do the work of tearing up the food without the aid
of a masticatory organ as well. Jaws are also wanting in the
Heteropoda, and in many of the Nudibranchiata and Tecti-
branchiata.
In the Cephalopoda the jaws, or ‘ beaks,’ as they are called,
are most formidable weapons of attack. In shape they closely
resemble the beaks of a parrot, but the hook on the dorsal side
of the mouth does not, as in birds, close over the lower hook,
but fits under it. Powerful muscles govern these mandibles,
which must operate with immense effect upon their prey
(Fig. 110).
The Radula.1A— When the food has passed beyond the opera-
1 The whole of the radulae and jaws figured in this work are taken from the
original specimens in the collection of the Rey. Prof. H. M. Gwatkin, who has
always been ready to give me the run of his cabinets, which probably contain
the finest series of radulae in the world. To his kindness I owe the following
description of the process of mounting: ‘‘ The first step is to obtain the radula.
Dissection is easy in species of a reasonable size. On opening the head from
above, so as to lay open the floor of the mouth, the radula itself is seen in most
of the marine species, though in others it is contained in a sort of proboscis ;
and in the Pulmonata and others the student will find the buccal mass, with
commonly a brown mandible at its front end, and the lingual ribbon in its
hinder part. The teeth may be recognised by their silvery whiteness, except in
a few cases like Patella and Chiton, where they are of a deep brown colour.
When obtained, the radula may be cleaned by boiling in a solution of caustic
potash. There is no risk of injury if the solution is not too strong.
‘¢Smaller species may be treated more summarily. The proboscis, the
buccal mass, or even the whole animal may be thrown into the potash solution
and boiled till scarcely anything is left but the cleaned radula. Remains of
animals dried inside the shell may be similarly dealt with, after soaking in clean
water. With a little care, this process will answer for shells down to the size
of Ancylus or Rissoa. The very smallest (Carychium, Tornatellina, Skenea,
etc.) must be crushed on the slide and boiled on it, after removing as much as
possible of the broken shell. The radula can then be searched for under the
microscope, and washed and mounted on the slide.
‘*The student must be warned that though the general process is simple,
there are difficulties in particular cases. In the Pulmonata, for example, mem-
branes on both sides of the radula need careful removal. Murex, Purpura, and
most of the Taentoglossa have the side teeth folded down over the central, so
that the arrangement is not well seen till they have been brushed back. The
Cones, again, have no basal membrane at all, so that if the potash is not used
with great care, the single teeth will fall asunder and be lost. Perhaps the
worst case is where a large animal has a radula as small as that of a Rissoa,
214 FUNCTIONS AND POSITION OF RADULA CHAP.
tion of the jaw, it comes within the province of the radula, the
front part of which perhaps co-operates to a certain extent with
Fic. 111.— Patella vulgata L., show-
ing the normal position of the
radula, which is doubled back in
a bow; the shell has been re-
moved, and the whole visceral
mass is turned forward, exposing
the dorsal surface of the muscular
foot: gr, longitudinal groove on
this surface; i, i; intestine; J,
Fic. 110.— Jaws of Sepia: A, in situ liver; m, m, mantle edge; mu,
within the buccal mass, several of muscles (cut through) fastening the
the arms having been cut away ; visceral mass to the upper sides of
B, removed from the mouth and the foot ; ov, ovary; 7, radula; u.f,
slightly enlarged. upper or dorsal surface of the foot.
the jaw in performing the biting process. The function of the
like Turritella, Harpa, or Struthiolaria, or where the radula is almost filmy in
its transparency, like those of Actaeon and the small Scalaria.
‘‘When once the radula is laid out, the mounting is commonly easy.
Canada balsam makes it too transparent. Fluids may be used, and are almost
necessary for thick radulae like those of large Chitons; but the best general
medium is glycerine jelly. It runs under the cover glass by capillary attraction,
and may be boiled (though only for a moment) to get rid of air bubbles. It
should then be left unfinished for several weeks. If cracks appear, the reason
is either that the jelly is a bad sample, or that it has been boiled too long, or
(commonly) that the object is too thick ; and there is not often any difficulty in
remounting. J have no serious complaint of want of permanence against the
medium, if I may speak from a pretty wide experience during the last twenty
years.””
vl TEETH OF THE RADULA ZH:
radula as a whole is to tear or scratch, not to bite; the food
passes over it and is carded small, the effect being very much
the same as if, instead of dragging a harrow over the surface of
a field, we were to turn the harrow points upwards, and then
drag the field over the harrow.
The radula itself is a band or ribbon of varying length and
breadth, formed of chitin, generally almost transparent, some-
times beautifully coloured, especially at the front end, with red
or yellow.t It hes enveloped in a kind of membrane, in the
floor of the mouth and throat, being quite flat in the forward
part, but usually curving up so as to line the sides of the throat
farther back, and in some cases eventually forming almost a
tube. The upper surface, z.e. the surface over which the food
passes, is covered with teeth of the most varied shape, size,
number, and disposition, which are almost invariably arranged
in symmetrical rows. These teeth are attached to the cartilage
on which they work by muscles which serve to erect or depress
them; probably also the radula as a whole can be given a for-
ward or backward motion, so as to rasp or card the substances
which pass over it.
The teeth on the front part of the radula are often much
worn (Fig. 112), and probably fall away by degrees, their place
being taken by others successively pushed up from behind. At
the extreme hinder end of the radula the teeth are in a nascent
condition, and there are often as many as a dozen or more
scarcely developed rows. Here, too, lie the cells from which
the teeth are originally formed.
The length and breadth of the radula vary greatly in differ-
ent genera. In Littorina it is very narrow, and several times
the length of the whole animal. It is kept coiled away like a
watch-spring at the back of the throat, only a small proportion
of the whole being in use. I have counted as many as 480 rows
in the common Littorina littorea. In Patella it is often longer
than the shell itself, and if the radula of a large specimen be
freshly extracted and drawn across the hand, the action of the
hooks can be plainly felt. In Aerope, the Turbinidae generally,
and Haliotis it is very large. In Turritella, Aporrhais, Cylichna,
1 The substance both of the jaw and radula is neither crystalline nor cel-
lular, but laminated. Chitin is the substance which forms the ligament in
bivalves, the ‘pen’ in certain Cephalopoda, and the operculum in many uni-
valves. Neither silica nor keratine enter into the composition of the radula.
216 SIZE OF RADULA— PRESENCE OR ABSENCE CHAP.
Struthiolaria, and the Cephalopoda it is small in proportion to
the size of the animal. In the Pul-
monata generally it is very broad,
the length not exceeding, as a rule,
thrice the breadth; in most other
groups the breadth is inconsider-
able, as compared to the length.
The Radula is wanting in two
families of Prosobranchiata, the
Eulimidae and Pyramidellidae,
which are consequently grouped
together as the section Gymno-
glossa. It is probable that in
_ these cases the radula has aborted
a rae ST a a rd through disuse, the animals hay-
Reeve, Panama), much worn by ing taken to a food which does not
eo require trituration.. Thus several
genera contained in both these families are known to live para-
sitically upon various animals — Holothurians, Echinoderms, etc.
—nourishing themselves on the juices of their host. In some
cases, the development of a special suctorial proboscis compen-
sates for the loss of radula (see pp. T6-77). In Harpa there is
no radula in the adult, though it is present in the young form.
No explanation of this fact has yet been given. It is also absent
in the Coralliophilidae, a family closely akin to Purpura, but
invariably parasitic on corals, and probably nourished by their
exudations. There is no radula in Entoconcha, an obscure form
parasitic on the blood-vessels of Synapta, or in Neomenia, a
genus of very low organisation, or in the Tethyidae, or sea-
hares, or in one or two other genera of Nudibranchiata.
The number of teeth in the radula varies greatly. When
the teeth are very large, they are usually few in number, when
small, they are very numerous. In the carnivorous forms, as a
rule, the teeth are comparatively few and powerful, while in
the phytophagous genera they are many and small. Large
hooked and sickle-shaped teeth, sometimes furnished with barbs
like an arrow-head, and poison-glands, are characteristic of
genera which feed on flesh; vegetable feeders, on the contrary,
have the teeth rounded, and blunter at the apex, or, if long
and narrow, so slender as to be of comparatively little effect.
VIII NUMBER AND ARRANGEMENT OF TEETH 217
Genera which are normally vegetarian, but which will, upon
occasion, eat flesh, e.g. Limax and Hyalinia, exhibit a form of
teeth intermediate between these two extremes (see Fig. 140, A).
In Chaetoderma there is but one tooth. In Aeolis coronata
there are about 17, in A. papillosa and Elysia viridis about 19,
in Glaueus atlanticus about 21,in Mona nobilis about 28. In
the common whelk (Buccinwm undatum) there are from 220 to
250, in the common periwinkle about 3500. As many as 8343
have been counted in Limnaea stagnalis, about 15,000 in Helix
aspersa (that is, about 400,000 to the square inch), about 50,000
in Limaxc maximus, and as many as 40,000 in Helix Ghies-
breghti, a large species from Mexico; they are very numerous
also in Nanina, Vitrina, Gadinia, and Actaeon. But Umbrella
stands far and away the first, as far as number of teeth is con-
cerned. In both U. mediterranea and U. indica they entirely
baffle calculation, possibly 750,000 may be somewhere near the
truth.
The teeth on the radula are almost invariably disposed in
a kind of pattern, exactly like the longitudinal rows of colour
in a piece of ribbon, down the centre of which runs a narrow
stripe, and every band of colour on one side is repeated in the
same relative position on the other side. The middle tooth of
each row — the rows being counted across the radula, not longi-
tudinally —is called the central or rachidian tooth; the teeth
next adjacent on each side are known as the /aterals, while the
outermost are styled wncini or marginals. As a rule, the dis-
tinction between the laterals and marginals is fairly well indi-
cated, but in the Helicidae and some of the Nudibranchiata it
is not easy to perceive, and in these cases there is a very gradual
passage from one set to the other.
The central tooth is nearly always present. It is wanting
in certain groups of Opisthobranchiata, some of the carnivorous
Pulmonata, and in the Conidae and Terebridae, which have lost
the laterals as well. Voluta has lost both laterals and marginals
in most of the species, and the same is the case with Harpa.
In Aeolis, Elysia, and some other Nudibranchiata the radula
consists of a single central row. Other peculiarities will be
described below in their proper order.
The extreme importance of a study of the radula depends
upon the fact, that in each species, and a fortiori in each genus
218 VALUE IN CLASSIFICATION CHAP.
and family, the radula is characteristic. In closely allied species
the differences exhibited are naturally but slight, but in well-
marked species the differences are considerable. The radula,
therefore, serves as a test for the distinction of genera and species.
For instance, in the four known recent genera of the family
Strombidae, viz. Strombus, Pteroceras, Rostellaria, and Terebel-
lum, the radula is of the same general type throughout, but with
distinct modifications for each genus; and the same is true,
though to a lesser extent, for all the species hitherto examined
in each of the genera. These facts are true for all known genera,
differences of the radula corresponding to and emphasising those
other differences which have caused genera to be constituted.
The radula therefore forms a basis of classification, and it is
found especially useful in this respect in dealing with the largest
class of all, the Gasteropoda, and particularly with the chief
section of this order, the Prosobranchiata. Thus we have —
(a) Tozxoglossa
(6) Rachiglossa
( Monotocardia | (c) Taenioglossa
(d) Ptenoglossa
Prosobranchiata | (e) Gymnoglossa
{ (f) Rhipidoglossa
Diotocardia ] (a). Deen
(a) Toxoglossa.— Only three families, Terebridae, Conidae,
and Cancellariidae, belong to this section. There is no central
tooth, and no laterals, the radula consisting simply of large mar-
ginals on each side. In Conus these are of great size, with a
hae base which contains a poison-gland (see p. 66), the con-
tents of which are carried to the point by a duct. The point is
always singly and sometimes doubly barbed (Fig. 116). When
extracted, the teeth resemble a small sheaf of arrows (Figs. 118,
115). A remarkable form of radula, belonging to Spirotropis
(a subgenus of Drillia, one of the Conidae), enables us to explain
the true history of the radula in the Toxoglossa. Here there
are five teeth in a row, a central tooth, and one lateral and one
marginal on each side, the marginals being very similar in shape
to the characteristic shafts of the Conidae (Fig. 114). It.is
evident, then, that the great mass of the Toxoglossa have lost
1 réfov, arrow; paxis, ridge, sharp edge; raivia, ribbon; mrnvés, winged ;
yuuvos, bare; piris, fan; doxds, beam.
Vul FORMULAE OF TEETH 219
both their central and lateral teeth, and that those which remain
are true uncini or marginals. Spirotropis appears to be the soli-
tary survival of a group retaining the primitive form of radula.
The arrangement of teeth in all these sections is expressed
by a formula applicable to each transverse row of the series.
The central tooth, if present, is represented by 1, and the laterals
and marginals, according to their number, on each side of the
Fic. 114.— Portion of radula of Spiro-
tropis carinata Phil., Norway. x70.
Fie. 113. — Radula of Bela turricula Mont. Fie. 115.— Eight teeth from the radula
x 70. of Terebra caerulescens Lam. x 60.
central figure. Thus the typical formula of the Toxoglossa is
1.0.0.0.1, the middle 0 standing for the central tooth which is
absent, and the 0 on each side of it for the absent laterals; the
1 on each extreme represents the one uncinus in each row.
Thus the formula for Spirotropis, which has also one lateral on
each side and a rachidian or central tooth, is 1.1.1.1.1. Often
the formula is given thus: aoe Ae, where 30 and 42
stand for the average number of rows of teeth in Conus and
Spirotropis respectively ; the same is sometimes expressed thus:
MeO scosOle LL «42.
220 RADULA OF THE RACHIGLOSSA CHAP.
(6) The Rachiglossa comprise the 12 families Olividae, Harpi-
dae, Marginellidae, Volutidae, Mitridae, Fasciolariidae, Turbi-
nellidae, Buccinidae, Nassidae, Columbellidae, Muricidae, and
Fic. 117. — Portion of the radula of Melongena
vespertilio Lam., Ceylon. x 30.
Fig. 116.— A tooth
from the radula
of Conus imperi-
alis L.,S. Pacific,
x 50, showing
barb and poison
duct. Fig. 118. — Portion of the radula of Eburna japonica
Sowb., China. x 30.
Fic. 119.— Portion of the
radula of Murex regius
Lam., Panama. x 60.
Coralliophilidae. Certainly most and probably all of these fam-
ilies are or have been carnivorous, the Coralliophilidae being a
degraded group which have become parasitic on corals, and
have lost their teeth in consequence. The characteristics of the
VIII RADULA OF THE RACHIGLOSSA O22) |
group are the possession of a central tooth with from one cusp
(Boreofusus) to about fourteen (Bullia), and a single lateral more
or less cuspidate, the
outer cusp of all being
generally much the larg-
est. Thus in Melongena
respertilio (Fig. 117) the
central tooth is tri-
cuspid, the central cusp
being the smallest, while Fic. 120 — Portion of the radula of Imbricaria
the laterals are bicuspid ; murnorata Swains. x 80.
in Hburnajaponica (Fig.
118) the central tooth is 5-cusped, the two outer cusps being much
the smallest. The teeth, on the whole, are sharp and hooked,
Fic. 121.— Three rows
of teeth from the
radula of F'asciola-
ria trapezium Lam.
x 40.
with a broad base and formidable cutting edge. In the Olividae,
Turricula, Buccinopsis, and the Muricidae the laterals are unicus-
pid and somewhat degraded (Fig. 119). In
Mitra and the Fasciolariidae they are very
broad and finely equally toothed like a comb
(Figs. 120, 121). The whole group is desti-
tute of marginals.
Several remarkable peculiarities occur.
Harpa loses the radula altogether in the adult.
In the young it has lost only the laterals,
and consists of nothing but the central tooth.
Fie. 122.—Six teeth Marginella has no laterals; the central tooth
from the radula of . :
Cymbium diadema 18 Small and comb-shaped, with blunt cusps.
pos torres Strait. In Voluta the laterals are generally lost, but
fs in Volutomitra and one species of Voluta! they
are retained. The central tooth usually has three strong cusps,
1V. concinna, according to Schacko (Conch. Mitth. i. p.126, Pl. xxiv. f. 5); the
lateral is large, strong, unicuspid on a broad base.
222 DEGRADED AND ABNORMAL RADULA CHAP.
and is very thick and coloured a deep red or orange (Fig. 122);
in the subgenus Amoria it is unicuspid, in shape rather like a
spear-head with broadened wings ;
in Volutolyria it is of a different
>) type, with numerous unequal den-
ticulations, something like the
laterals of Mitra or Fasciolaria.
9 Of the Mitridae, Cylindromitra
has lost the laterals. Among the
- ; Buccinidae, Buccinopsis possesses
H a curiously degraded radula, the
central tooth having no cusps, but
being reduced to a thin basal
A’ plate, while the laterals are also
weakened. This degradation from
the type is a remarkable feature
—— among radulae, and appears to
5 ae be characteristic, sometimes of a
fete errs ele ade raed fortis whole family, e.g. the Columbeili-
of radula: A, Cantharus pagodus dae (Fig. LZ. B); sometimes of
Reeve, Pana oaseent en) 40: 4 genus, sometimes again of a
portion; B, Columbella varia Sowb., single species. Thus in Cantha-
ema rus (a subgenus of Buccinum)
the radula is typical in the great majority of species, but in
C. pagodus Reeve, a large and well-grown species, it is most
remarkably degraded, both in the central and lateral teeth
(Fig. 123, A). This circumstance is the more singular since
Fic. 124. — Three rows of the radula of Sistrum spectrum Reeve, Tonga. x 80.
The laterals to the right are not drawn in.
C. pagodus lives at Panama side by side with C. ringeus and
C. insignis, both of which have perfectly typical radulae. It is
probable that the nature of the food has something to do with
the phenomenon. Thus Sistrum spectrum Reeve was found to
possess a very aberrant radula, not of the common muricoid
VIII RADULA OF THE TAENIOGLOSSA 223
type, but with very long reed-like laterals. This singularity
was a standing puzzle to the present writer, until he was fortu-
nate enough to discover that S. spectrum, unlike all other spe-
cies of Sistrum, lives exclusively on a branching coral.
The dental formula for the Rachiglossa is thus 1.1.1, except
in those cases where the laterals are absent, when it is 0.1.0.
(c) The Taenioglossa comprise 46 families in all, of which
the most important are Tritonidae, Cassididae, Cypraeidae,
Strombidae, Cerithiidae, Turritellidae, Melaniidae, Littorinidae,
Rissoidae, Paludinidae, Ampullariidae, Cyclophoridae, Cyclo-
\(\
Fic. 125. — Portion of the radula of Cassis su/cosa Born., x 40. The marginals
to the right are not fully drawn.
stomatidae, and Naticidae. The radula is characterised by a
central tooth of very variable form, the prevailing type being
multicuspid, the central cusp the largest, on a rather broad base ;
a single lateral, which is often a broad plate, more or less cusped,
and two uncini, rather narrow, with single hooks, or slightly
Fic. 126.— Four rows of teeth
from the radula of Vermetus
grandis Gray, Andamans.
x 40.
cusped. The accompanying figures of Cassis, Vermetus, and
Cypraea, and those of Littorina and Cyclophorus given on pp.
20, 21, are good examples of typical taenioglossate radulae.
In Homalogyra the radula is much degraded, the central
tooth is large and trianglar on a broad base, the lateral is
represented only by a thin oblong plate, and the uncini are
absent. In some species of Jeffreysia the uncini are said to be
absent, while present in others. Lamellaria has lost both its
uncini, but the radula of the allied Velutina is quite typical. A
peculiar feature in this group is the tendency of the marginals
to increase in number. A stage in this direction is perhaps
224 RADULA OF THE TAENIOGLOSSA CHAP.
seen in Ovula, Pedicularia, and the Cyclostomatidae. Here the
outermost of the two marginals is by far the larger and broader,
and is strongly pectinated on its upper edge; in the Cyclostoma-
Fig. 127.—Two rows of the
radula of Cypraea tigris L.
x 30.
tidae the pectinations are rather superficial; in Ovula (where
both marginals are pectinated) they are decidedly deeper; in
Pedicularia they are deeper still, and make long slits in the
tooth, tending to subdivide it altogether. In Turritella the
number of marginals is said to vary from none (in 7’. acicula) to
three (7. triplicata), but the fact wants confirmation. Solariwin
is an aberrant form, possessing simply a number of long uncini,
which recall those of Conus or Pleurotoma, and is therefore hard
to classify ; the allied Torinia has a radula which appears allied
to Ovula or Pedicularia. In Triforis the teeth are identical
throughout, very small, about 27 in a row, tricuspid on a square
base, cusps short.
The normal formula of the Yaenioglossa is 2.1.1.1.2; in
Lamellaria, 1.1.1; in Triforis, 18.1.18, or thereabouts.
(d) Ptenoglossa.— This
section consists of two
families only, which cer-
tainly appear remarkably
dissimilar in general habits
and appearance, viz., the
Ianthinidae and Scalarii-
dae. In all probability
their approximation is
only provisional. The
Fie. 128. — Portion of the radula of Janthina yadula, which in Janthina
comniunis Lam. x 40.
is very large, and in Sea-
larva very small, possesses an indefinite number of long hooked
VIII RADULA OF THE PTENOGLOSSA, ETC. 225
teeth, of which the outermost are the largest. The central
tooth, if present (it does not occur in Janthina), is the smallest
in the series, and thus recalls the arrangement in some of the
carnivorous Pulmonata (p. 232). In Lanthina the radula is
formed of two large divisions, with a gap between them down
the middle.
The formula is o.1.00 or o.0.00 according as the central
tooth in Scalaria is or is not reckoned to exist.
(e) Gymnoglossa. — In the absence of both jaw and radula
it is not easy to classify the two families (Eulimidae and Pyra-
midellidae) which are grouped under this section. Fischer
regards them as modified Ptenoglossa; one would think it more
natural to approximate them to the Taenioglossa.
Fia. 129. — Portion of the radula of Margarita umbilicalis Brod., Labrador.
x 75 and 300.
(f) Rhipidoglossa.— This section consists of seventeen
families, the most important being the Helicinidae, Neritidae,
Turbinidae, Trochidae, Haliotidae, Pleurotomariidae, and Fissu-
rellidae. The radula is characterised by —
(1) The extraordinary development of the uncini, of which
there are so many that they are always reckoned as indefinitely
numerous. They are long, narrow, hooked, and often cusped
at the top, and crowded together like the ribs of a fan, those at
the extreme edge not being set straight in the row, but curving
away backwards as they become smaller; in Solariella alone,
where there are from five to ten, can they be counted.
(2) The varying number of the laterals. The average num-
VOL. IJ Q
226 RADULA OF THE RHIPIDOGLOSSA CHAP.
ber of these is five on each side; in some cases (Livona) there
are as many as nine, in some (Weritopsis) only three. The
lateral next to the uncini (which is specially large in the
Neritidae, and is then known as the capituliform tooth) is
regarded by some authorities as the first uncinus, by others as
the sole representative of the laterals, the teeth on the inner
side of it being reckoned as multiplied central teeth. Accord-
ing to this latter view, Livona will have as many as seventeen
central teeth. Taking five as the average number of ‘ laterals,’
we shall have the following different ways of constituting the
rhipidoglossate formula, the first being that to which preference
is given, V1Z.: —
(1) 5.1.5.0, ze. one central, five laterals, including the
‘last lateral’ tooth.
(2) (o.1).4.1.4.(1.0 ), regarding the ‘last lateral’ as first
uncinus, but specialising it by a number.
(3) o.1.(4.1.4).1.0, regarding the ‘last lateral’ as the only
lateral.
In the Neritidae and the derived fresh-water genera (Neritina,
Navicella) the first lateral, as well as the capituliform tooth, is
Fic. 130. — Portion of the radula of Nerita albicilla L., Andaman Is., with central
tooth highly magnified : c, c, the capituliform tooth. ~ 40.
very large, and in shape rather like the blade bone of a shoulder
of mutton; the intervening laterals are very small. In Neri-
topsis (a degraded form) the central tooth and first lateral
are entirely wanting. In the neritiform land-shells (Helicina,
Proserpina) the first lateral is no larger than the others, while
the capituliform tooth is enormous. Hydrocena is a very aber-
rant and apparently degraded form; the laterals between the:
first and the capituliform tooth are all wanting. In Halvotis,
Scissurella, and. Pleurotomaria the five laterals are of fauly
vin RADULA OF THE DOCOGLOSSA 227
equal size; in Fissurella we again meet with a large capituliform
tooth, with very small laterals.
(g) The Docoglossa are in direct contrast with the Rhipido-
glossa in possessing few and strong teeth, instead of many and
weak. There are only three families, Acmaeidae, Patellidae,
and Lepetidae. In some of the Acmae-
idae there are not more than two
teeth in a row, while in no species are
there more than twelve. The radula
is, however, very long: there are as
many as 180 rows in Patella vulgata.
The teeth are thick, generally of a
very deep red horn colour, rather
opaque. The cartilage in which they
are set is remarkably thick, and in
some species whose teeth are very few Fie. 131.— Portion of the radula
; : ; : of Patella cretacea Reeve,
a considerable portion of this cartilage geen in half profile. x 40.
is left quite bare.
Although the teeth are so few, the arrangement is by no
means simple. The special feature of the group is the multipl-
cation of identical centrals. Of these there are two in Acmaea,
and four, as arule,in Patella. Thus in these two genera there is
seldom an absolutely central tooth. Either laterals or marginals
are liable to be lost, but there are never more than two of either
in Aemaea, and never more than two laterals and three marginals
in Patella. Thus the formula varies from 0.0.(1 + 0 + 1).0.0 in
Fic. 132. — Two rows of
the radula of Pte7ro-
trachea mutica Les.,
Naples. x 60.
Pectinodonta, 2.2.1 +0 +41).2.2 in Collisellina (both Acmaei-
dae), to 3.2.01 + 0 +1).2.3 in Patinella, and 3.1.(2 + 0 + 2).1.8
in Patella proper. In the Lepetidae there is an absolutely
central tooth, which appears to be made up of the coalescence
of several teeth, no laterals, and about two marginals; formula,
2.071.032:
228 RADULA OF HETEROPODA AND AMPHINEURA CHAP.
The radula of the Heteropoda is quite characteristic, and
shows no sign of affinity with any other Prosobranchiate. The
central tooth is large, broad, tricuspid, and denticulated on a
broad base; the single lateral is strong, often bicuspid; the two
marginals simple, long, falciform; formula, 2.1.1.1.2 (Fig. 132).
Amphineura. — (a) Polyplacophora.— The radula of the
Chitonidae is quite unique. It resembles that of the Docoglossa
in being very long, and composed of thick and dark horn-col-
oured teeth. The number of teeth, however, is considerably
Fiac. 133.— A, Portion of the radula of Chiton (Acanthopleura) spiniger Sowb., An-
damans, x 30; B, portion of the radula of Dentalium entalis L., Clyde, x 50.
ereater, amounting almost invariably to seventeen in each row.
There are three rather small central teeth, the two outer of
these being similar; next comes a very large lateral (the major
lateral), usually tricuspid, which is followed by two much
smaller laterals, which are scarcely more than accessory plates ;
then a very large and arched marginal (the major uncinus), at
the outer side of which are three accessory plates. Some con-
sider there is only one central tooth, and count the two small
teeth on each side of it as laterals.
Thus the formula is either (8+1).(24+1) .2.(1+2).d1+8)
or (84+1).(24141).1.0414+2).(14+8). :
(6) Aplacophora.— Of this rather obscure order, Chaetoderma
has a single strong central tooth, Meomenia has no radula,
VII RADULA OF OPISTHOBRANCHIATA 229
Proneomenia and Lepidomenia have about twenty falciform
teeth, much larger at one end of the radula than the other;
formula, 0.1.0.
Opisthobranchiata. — The radula of the Opisthobranchiata
is exceedingly variable in shape, size, and number and character
of teeth. Not only do allied families differ greatly from one
another, but allied genera often possess radulae widely distinct
ibe Be
a"
avi \ \\ | |
\
‘ \ f WW f hf
\ \ ‘ , ‘eee a
\s eg — = a
: Y <> 7
J Fic. 1584. — Two teeth from the radula of \
/ Aeolis papillosa L. x 55. \
in plan. Thus, among the Polyceridae, Goniodoris has no cen-
tral tooth, one large lateral and one marginal (form. 1.1.0.1.1) ;
Doridunculus the same, with five marginals (form. 5.1.0.1.5);
Lamellidoris one each of median, laterals, and marginals
(1.1.1.1.1); ZIdalia, Anecula, and Thecacera the same as Gonio-
doris; Crimora several each of laterals and marginals. Even
species of the same genus may differ; thus the formula for
Aeolis papillosa is 0.1.0, but for Ae. Landsbergi 1.1.1; for Philine
aperta 1.0.1, but for Philine pruinosa 6.0.6.
It must not be forgotten, however, that a simple repetition
of the same tooth, whether lateral or marginal, does not nec-
essarily constitute an important characteristic, nor does the
presence or absence of a central tooth. In most of the cases
mentioned above, the difference in the number of laterals and
marginals is due to the multiplication of identical forms, while
the central tooth, when present, is often a mere plate or narrow
block without cusps, whose presence or absence makes little
difference to the character of the radula as a whole.
There appear to be three well-marked types of radula among
the Opisthobranchiata.
(a) Radula with a single strong central tooth, rows few.
230 RADULA OF OPISTHOBRANCHIATA CHAP.
This form is characteristic of the Aeolididae, Fionidae, Glaucidae,
Dotoidae, Hermaeidae, Elysiidae (Fig. 185), and Limapontiidae.
In the Aeolididae it is sometimes accompanied by a single
lateral. The same type occurs in Ozynoe, and in Lobiger (=
Lophocercus).
(6) Radula with the first lateral very strongly developed.
This type may take the form of (1) a single lateral, no central
or marginals, e.g. Onchidoris, Scaphander (Fig. 187, A), Philine
(certain species), Ringicula, or (2) first lateral strongly devel-
oped, and repeated in succeeding laterals (2-6) on a smaller
scale, e.g. Philine (certain species). A few marginals are some-
~— se 4
LGU ESN
LUTE NP Now SS
= ZY Ugn~s SST“
Fic. 135.— Radula of Elysia Fig. 136.— Portion of the radula
viridis Mont. x40. Type of Gadinia peruviana Sowb.,
(a). Chili. x 250. Type (c).
times added, e.g. in Polycera, Lamellidoris (where there is a
degraded central tooth, Fig. 137, B), Idalia, and Ancula.
(e) Radula with an indefinite number of marginals, laterals
Gf present) merging into marginals, central tooth present or
absent, inconspicuous, teeth all very small. This type of radula,
among the Nudibranchiata, is characteristic of certain subgenera
of Doris (e.g. Chromodoris, Aphelodoris, Casella, Centrodoris), of
Aypobranchiaea and Pleurophyllidia; among the Tectibranchiata,
of Actaeon, many of the Bullidae, Aplustrum, the Aplysiidae,
Pleurobranchus, Umbrella and Gadinia (Figs. 136 and 187, C).
In the Pteropoda there are two types of radula. The Gym-
nosomata, which are in the main carnivorous, possess a radula
with a varying number (4-12) of sickle-shaped marginals, cen-
tral tooth present or absent. In the Thecosomata, which feed
on a vegetable diet, there are never more than three teeth, a
central and a marginal on each side; teeth more or less cusped
on a square base.
VII RADULA OF PULMONATA 221
Pulmonata. — The radula of the Testacellidae, or carnivo-
rous land Mollusca, is large, and consists of strong sickle-
shaped teeth with very sharp points, arranged in rows with or
without a central tooth, in such a way that the largest teeth are
often on the outside, and the smallest on the inside of the row
(as in Rhytida, Fig. 189). The number and size of the teeth
vary. In Testacella and Glandina, they are numerous, consist-
ing of from 30 to 70 in a row, with about 50 rows, the size
throughout being fairly uniform. In Aerope they are exceed-
Fic. 137. — Portions of the
radula of Opisthobranchi-
ata, illustrating types ())
and (c); A, Scaphander lig-
narius L.; A’, one of the
teeth seen from the other
side, x 40; B, Lamellidoris
bilamellata L., Torbay, x
60; C, Hydatina physis L.,
E. Indies, x 75.
ingly large, and only eight in a row, the outermost marginal
being probably the largest single tooth in the whole of the
Mollusca. The central tooth is always obscure, being, when
present, simply a weaker form of the weakest lateral; in genera
with only a few teeth in a row it is generally absent altogether.
The first family of jaw-bearing snails, the Selenitidae, is
distinctly intermediate. The possession of a jaw relates it to
the main body of Helicidae, but the jaw is not strong, while the
teeth are still, with the exception of the central, thoroughly
Testacellidan. The central tooth is quite rudimentary, but it is
232 RADULA OF PULMONATA CHAP.
something more than a mere weak reproduction of the marginals.
There are no true laterals. The Limacidae show a further stage
in the transition. Here the central tooth has a definite shape of
its own, tricuspid on a broad base, which is more or less repeated
in the first laterals; these, as they approach the marginals,
Fic. 138. — Portion
of the radula of
Glandina trun-
cata Gmel. x 40.
gradually change in form, until the outer marginals are again
thoroughly Testacellidan This is the general form of radula,
varied more or less in different genera, which occurs in Wanina,
Helicarion, Limax, Parmacella, and all the subgenera of Zonites.
It is certain that some, and probable that all of these genera will,
|
' Fig. 139. — Portion
of the radula of
Rhytida Kraussit
Pir., 3S; > Adrica:
x 25.
on occasion, eat flesh, although their usual food appears to be
vegetable. The jaw is more powerful than in the Selenitidae,
but never so large or so strongly ribbed as in Helix proper.
When we reach the Helicidae, we arrive at a type of radula
1 In some cases (e.g. Hyalinia inornata) the laterals are very few, while in
Zonites laevigatus the first side tooth is more of a marginal than a lateral.
Vill RADULA OF PULMONATA 235
in which the aculeate form of tooth—so characteristic of the
Agnatha — disappears even in the marginals, and is replaced by
teeth with a more or less quadrate base; the laterals, which are
always present, are intermediate in form between the central and
the marginals, and insensibly pass into the latter. In size and
number oi cusps the first few laterals resemble the central tooth ;
in the extreme marginals the cusps often become irregular or
evanescent. As a rule, the teeth are set squarely in the rows,
with the exception of the extreme marginals, which tend to slope
away on either side. In some Helicidae there is a shght approxi-
mation to the Zonitidae in the elongation of the first marginals.
The above is the type of radula occurring in the great family
Helicidae, which includes not only Helix proper, with several
thousand species, but also Arion, Bulimus, Ariolimax, and other
genera. The jaw is almost always strongly transversely ribbed.
In the Orthalicidae (Fig. 140, C) the teeth of the radula,
instead of being in straight rows, slope back at an angle of
about 45 degrees from the central tooth. The central and
laterals are very similar, with an obtuse cusp on rather a long
stem; the marginals become bicuspid.
In the Bulimul/dae, which include the important genera
Placostylus, Amphidromus, Partula, Amphibulimus, and all the
groups of South American Bulimulus, the jaw is very charac-
teristic, being thin, arched, and denticulated at the edges, as if
formed of numerous narrow folds overlapping one another. The
radula is like that of the Helicidae, but the inner cusp of the
laterals is usually lengthened and incurved. In Partula the sep-
aration between laterals and marginals is very strongly marked.
The remaining families of Pulmonata must be more briefly
described. In the Cylindrellidae there are three distinct types
of radula: (a) Central tooth a narrow plate, laterals all very
curiously incurved with a blunt cusp, no marginals (Fig. 140,
D); (2) radula long and narrow, central tooth as in (@), two
laterals, and about eight small marginals; (¢) much more heli-
cidan in type, central and laterals obtusely unicuspid, marginals
quite helicidan. Type (c) is restricted to Central America,
types (a) and (6) are West Indian.
Pupidae: Radula long and narrow; teeth of the helicidan
type, centrals and laterals tricuspid on a quadrate base, mar-
ginals very small, cusps irregular and evanescent. This type
234 RADULA OF PULMONATA CHAP,
includes Anostoma, Odontostomus, Buliminus, Vertigo, Strophia,
Holospira, Clausilia, and Balea.
Stenogyridae, including Achatina, Stenogyra, and all its sub-
genera: Central tooth small and narrow, laterals much larger,
tricuspid, central cusp long, marginals similar, but smaller.
Achatinellidae: Two types occur; (@) teeth in very oblique
rows, central, laterals, and marginals all of the same type, base
narrow, head rather broad, with numerous small denticles
(Achatinella proper, with ae
Blianca y pertenecientes a una, el Himalaya, se librarian del ca-
t( secta religiosa, se quedaron espe-
t], rando el momento anunciado
b —precisamente a las 2:45 P. M.
(8:45 A. M., hora de Nueva
6,, York)— en que el Angel Gabriel
tl daria, al fin, el temido trompetazo
y una bomba de mercurio estalla-
it|ria con potencia tal que inclina-
ria 45 grados el Eje de la Tierra.
ny Las grandes masas ocedaicas inun-
fc| darian islas y continentes y s6lo
los escogidos, que estarian refu-
5 giados en el Monte Blanco, en
F Atalia; y en el Monte Everest, en|
to
inte
when the valves are closed.
'taclismo para volver a poblar la
Tierra.
No se sabe si habia otro grupo >
esperando el momento en el Mon-
te Everest, pero el pediatra de
Milan, que se llama a si mismo
“Emman” del culto, aguardaba
con su gente, en un chalet arren-
dado en el Monte Blanco, la mi~eg,
sidn de nuevo Noé.
A punto de llegar el momento, a
alguien del grupo, muy segunda a
mitad del Siglo XX, empezo a ye
(PASA a la pagina 32)
Se ur
1e€
Sa Rl U2 ulUil Cath be seen
As a rule, the two portions are
intimately connected with one another, the ligament folding
ie the cartilage, but in some cases, e.g. Mya, Mactra, where
€ cartilage is lodged within the hinge, they are completely
disconnected (Fig. 1 Sit)
7 = Pecten the external ligament is very thin, and runs along
1e dorsal margi internal li 1
¢ gin, while the internal ligament is large, solid,
and situated in a shallow pit.
In Perna, where the hinge is
270 PARTS OF THE SHELL IN BIVALVES CHAP.
impressions. The impression produced by the muscular edge of
the mantle, which curves downwards and backwards from the
anterior adductor impression, is known as the pallial line. In
shells with only one muscle it is represented by an irregular
row of small marks, or disappears altogether (Ostrea). The
pallial sinus is produced by the muscles which retract the siphons,
and is most marked in those genera in which the muscles are
powerful and the siphons large (e.g. Tellina, Mya). It is entirely
° o14-LCama, Z futacas, Mesa Cocke
absent In genera 2 Mesas Esquineras, 2 lampa-
as y JGO. COMEDOR 5 Piezae
tode nuevo): Adeimas seleccién de
Z EFRIGERADORA usada oe TELE-
SsISION. Pequefio cargo de Crédi-
g4). Tenemos Faciles Términos de
“7 srédito. Sin Bancos. Sin Inconve-
alll jientes. Un Regalo Gratis para
odos. Si Ud. solamente quiere nn
Inez de Cuarto nesotros podemos
We dividir el Grupo.
ague $4Sem. SOLO $189
, CAIRE'S
. WAREHOUSE OUTLET
3ra. Ave. Entre Calles 80 y 81
VMuugurante el invierno nosotros ire-
mos a buscarlo a su casa.
«lame al sefior Lopez y haga ana
Fic 184. — Lett vale .cita a su conveniencia sin
a = obligacion.
» anterior, 5, aRA SU CONVENIENCIA ES-
D, ventral marg4AMOS ABIERTO A DIARIO DE
breadth of shell. 9. LLAME HOY AL GERENTE
a.m, anterior ; Depto. E-U3-F.
tor muscle; p, pa . LEhigh 35-5003
sinus ; /, ligament yeg al Sr. Lopez — Llame hoy 0
c, cardinal teeth aria y Domingo a cualquier hora.
tooth; p.l, p a LE 5-5003
the valves as ri;
that the siphons
-
: laber constructiva! ... oe!
Right and 1 ae
OBSERVACIONES
El nuevo Director de la O;
de Ja Oficina del Trabajo aqui,
anos Director de -Organizaciér
tal posicién para ir a desem
Comisién de Relaciones entre,
leva colaborando 25 afios con sus
Publicas” entre los suyos y el
minoritarios (y hasta mayoritari
Ge unos y de otros... ee |
é LIDERES PUERTORRIQ)
En una entrevista que ‘Joe He
por la radio, Monserrat le pregur
puerterriquenos” en esta gran m
nada mas que -irse a.la comunidad
mos por ahi. Cuanta persona que
trabajando por el bienestar de la «
inteligencia y trabajando dia por
labor de liderate que viene realiza
-eerse gue nosotros los puertorric
700.606 en N. Y¥. (setecientos mil |
para mejorar nuestra ciudad”...
f 2a
from him; in tleposreron ere valve edo Ce Pentre Cree ene
right valve, and the valve to the left the left valve. If, however,
the animal is not present, it may be remembered that the liga-
ment is nearly always behind the beaks, and that the beaks, as a
rule, point forward, thus the right and left valves can generally
be named by observation of the beaks and ligament. When
the ligament is median to the valves (e.g. Ostrea, Pecten), and the
beaks are not curved, the valves may be recognised by noting
the fact that the impression of the adductor muscle (in these
fe ais
IX THE LIGAMENT AND HINGE 2/1
cases always single) is nearer to the posterior than to the anterior
side. In a similar way the pallial impression, which only forms
a sinus on the posterior side, furnishes a guide to the valves of
Donaz, in which the beaks point backward, and of Tellina, in
which the beaks are frequently central.
In the fixed inequivalves (e.g. Chama) it is sometimes the
right, sometimes the left valve which is undermost, but the fixed
valve, whether right or left, is always deep, and the free valve
flat. Ostrea and Anomia are always fixed by the left valve.
The Junule is a well-marked area in front of and close to the
umbones, usually more or less heart-shaped, and
limited by aridge. Generally it is shallow, but
sometimes, as in Dosinia, Opis, and some Car-
dium, deeply impressed. A corresponding area
behind the umbones, enclosing the ligament, is
called the escutcheon (Fig. 186), but it seldom
occurs.
The ligament is a more or less elastic band,
be
which unites the two valves along a line adjacent es
to the umbones. As a rule, the greater part of Fic. 186.— Venus
subrostrataLam.:
the ligament is external to the shell, but it may ¢5 esentcheon;
be entirely internal. It is placed, normally, /%, ligament; lu,
; ; Tonule’s %;20: a,
behind the umbones, but in a few cases, when ympones.
the hinge line is very long (Areca, Pectunculus),
it extends in front of them as well. The edges of the valves,
when the ligament is mainly external, are more or less excavated
for its reception. When internal it is generally contained in a
groove or spoon-shaped pit, known as the fossette (compare
Fiz, 187).
The ligament consists of two distinct parts, which may occur
together or separately, the external, or ligament proper, and the
internal, or cartilage... Only the external portion can be seen
when the valves are closed. As a rule, the two portions are
intimately connected with one another, the ligament folding
over the cartilage, but in some cases, e.g. Mya, Mactra, where
the cartilage is lodged within the hinge, they are completely
disconnected (Fig. 187).
In Pecten the external ligament is very thin, and runs along
the dorsal margin, while the internal ligament is large, solid,
and situated in a shallow pit. In Perna, where the hinge is
272 THE LIGAMENT AND HINGE CHAP.
toothless, the ligament is folded into a number of transverse
ridges, which fit into corresponding grooves in the shell.
The lgament proper is zmelastic and insoluble in caustic
potash. The cartilage is very elastic, composed of parallel
fibres, shghtly iridescent, and soluble in caustic potash.
The operation of the hgament — using the word as including
the whole ligamental process —is in opposition to that of the
adductor muscles. When the latter
close the valves, they compress the
ligament, an action which its elas-
ticity resists: thus its operation
tends in part towards keeping the
valves open. But when lgament
and cartilage are both fully de-
veloped, they work in opposition to
one another, the ligament, by its
resistance to compression, prevent-
ing any straining of the adductor
muscles when the valves are open,
¥ en: Seapets pee? and the cartilage, for the same
edulis King; ca, cardinals; 7.4, reason, preventing the ventral mar-
anterior laterals; /.p, posterior _-; ; :
laterals; f, fossette; ¢, cartilage; @inS of the shell from closing too
1, ligament. rapidly upon one another when the
valves are being shut.
The Hinge. — The valves of Pelecypoda are generally articu-
lated, below the umbones, by a Ainge which is furnished, in the
majority of cases, with interlocking teeth, small pits or depres-
sions in each valve corresponding to the teeth in the other.
The teeth are distinguished as cardinal, or those immediately
below the umbo, and lateral, or those to either side of the car-.
dinals, the latter being also distinguished as anterior and pos-
terior laterals, according as they are before or behind the umbo
(Fig. 184). In shells which are tolerably equilateral there is no
difficulty in distinguishing between cardinal and lateral teeth.
But when they are very inequilateral, the whole hinge may
share in the inequality of growth, and an anterior lateral may
be thrown backward and simulate a cardinal, or a cardinal
may be thrown backward and simulate a posterior lateral (e.g.
Cardita, Unio, Fig. 188). In many Chama the cardinals are
pushed up into the umbo and become a mere ridge, while the
De THE LIGAMENT AND HINGE 273
strong anterior lateral becomes nearly central and simulates a
cardinal.
Some bivalves, e.g. Anodonta, Ostrea, Pedum, many Mytilus,
have no hinge teeth at all, in others the laterals are wanting
Fic. 188.— Hinges of A, Cardita semiorbiculata Brug., and B, Unio rectus Lam.,
showing how, in inequilateral shells, the lateral teeth tend to shift their position.
a.m, anterior adductor, p.m, posterior adductor muscle; ¢, c, cardinal teeth;
p.l, posterior lateral teeth; /, ligament.
(Psammobia, Diplodonta). In the Arcadae the hinge consists
of a number of very similar denticles, which are often serrated
like the teeth of a comb (Fig. 189).
Hinge-teeth are probably, in origin, derived from the crenula-
sabia
Ai
~—
KAKNLARAAAS SS ULE
Fic. 189. — The hinge in Arcadae : Fic. 190.—A, Tridacna scapha Lam.; B,
A, Nucula Loringi Ang. x 4; Cardium enode Sowb., showing the inter-
B, Arca granosa L.; u.a, um- locking of the ventral margins.
bonal area.
tions or ribbings of the surface of the shell, the upper ends of
which impinge upon the dorsal margin and mark it in a way
which is quite recognisable when the shell is thin. Similar
crenulations, resulting in interlocking of the valves, are not
VOL, IL T
274 HINGE-TEETH AND OTHER PROCESSES CHAP.
uncommon upon the ventral margin in certain genera (Fig. 190).
The mechanical effect of these continued riblets, when fitted
together on the opposing valves, would be to prevent the valves
sliding upon one another while closing, or after being closed.
Thus there would be a probability of their surviving, even after
the ribbing had disappeared from the surface of the shell, the
increased strength given by the hinge compensating for, and
making it possible to do without, the extra strength supplied by
the ribs. It is therefore possible that the teeth of the Nuculidae
and Arcadae, which have no distinction between cardinals and
laterals, represent a very ancient type, from which have been
evolved the various forms of hinge in which cardinals and laterals
are distinguished. Even in some forms of Arcadae (comp. Pec-
tunculus) we get a hint how the transverse teeth of the typical
Arca may have become transformed into the longitudinal tooth
of the normal lateral.!
The developed hinge-teeth, then, ensure the opening of the
valves in one direction; they also secure their accurate closure
upon.one another in exactly the same plane. Exposed shells
and gaping siphons matter little to animals which are protected
by their burrowing propensities, but to those which live in
material which can be easily penetrated by their foes, it must be
of advantage to be able to buckle their armour absolutely tight.
The edentulous hinge of Anodonta is a degeneration from a
dentate type, which retains its teeth (in Unio, etc.) when subject
to the jar of rapid streams, but tends to lose them in the stiller
waters of canals, lakes, and ponds.
Other processes in the bivalve shell.—In Anatina each umbo
is fissured and strengthened on the inside by a kind of umbonal
plate which carries the ligament. Some forms of Liligna de-
velop a strong internal umbonal rib, which serves as a buttress
to strengthen the shell. In Pholas, the so-called falciform pro-
cess serves as a point of attachment for the muscles of the foot
and viscera. There is no ligament or hinge-teeth, the place of
the latter being taken by the anterior adductor muscle, which is
attached to the hinge-plate, the latter being reflected back into
the shell.
In Septifer the anterior adductor muscle is carried on a
sort of shelf or myophore, and in Cucullaea the posterior
1W. H. Dall, Amer. Journ. Sc. xxxviii. p. 445 f.
rs MEASUREMENT—THE PERIOSTRACUM 25
adductor is partly raised on a similar and very prominent
formation.
Length and breadth of bivalve shells is variously measured.
Most authorities measure length, or ‘ antero-posterior diameter,’
by a straight line drawn from the extreme anterior to the
extreme posterior margin, and breadth by a similar line, drawn
from the umbones to a point, not very clearly marked, on the
opposite ventral margin (see Figs. 184 and 185). Others, less
correctly, reverse these terms. TZnickness is measured by the
extreme distance of the opposite faces of the closed valves.
As a rule, the length exceeds, and often greatly exceeds, the
thickness, but in a few cases—e.g. the Cardissa section of
Cardiwm — this is reversed.
The periostracum.— Nearly all shells are covered, at some
period of their growth, by a pertostracum,! or surface skin, which
serves the purpose of protecting the shell against the destructive
effects of the chemical action set up by water or air. It also, in
some cases (see p. 258), acts as a kind
of base upon which the shell is de-
posited. In old shells it is commonly
worn away, especially at those parts
which are likely to become abraded.
The form and composition of the
periostracum varies greatly. Some-
times (e.g. Oliva) it is a mere trans-
parent film, at others (Zonites) it is
transparent, but stout and solid. It
is corneous in Solenomya, covered
with fine hairs in many Helicidae, in
Conus, Velutina, and Cantharus it is
thick, fibrous, and persistent; in Tri- pe
191; —“Triton oleariuny.1:.,
chotropis and some Triton it is fur- Mediterranean, an example of
a Shell with a stout and hairy
nished with long bristles on a thick periostracum. x .
ground (Fig. 191). In fresh-water
shells it is usually rather thick, in order to protect the shell from
the erosive powers of certain kinds of water. In some cases
(Mya, Anatina) the periostracum is continued over the siphons,
so as to form a protection throughout their whole length.
1 The term epidermis, as distinct from periostracum, is properly restricted ta
the outer layer of the skin of the mantle and body generally.
276 EROSION OF THE SHELL CHAP. IX
Erosion. — The fresh-water Mollusca generally, and marine
mollusca in a few rare cases (Purpura, Littorina) are subject to
erosion, or decay in the shell substance. In univalves erosion
usually sets in near the apex (Fig. 192), where the life of the
shell may be regarded as weakest, and in bivalves
near the umbones. It is commonest in old shells,
and rarely occurs in the very young. So long as
the periostracum is present to protect the shell,
erosion cannot set in, but when once it has been
removed the shell is liable to the chemical changes
set up in its substance by water. There is abun-
dant evidence to show that erosion is caused by
pollution of water. Out of many instances one
must suffice. Ina certain stream near Boston, U.S.,
AG ee numbers of Mollusca occurred, the shells of which
ample of an Were very perfect and free from disease. Some
eroded fresh- little way down stream an alkaline manufactory
water shell : : :
(Melaniacon- Grained its refuse into the water. At and below
fusa Dohrn, this point for some distance every shell was more
Ceylon). :
or less eroded, most of them seriously. Farther
down, when the alkali refuse became diluted away, the shells
retained their normal condition.1
A small percentage of lime in the water appears to produce
erosion. The result of some experiments by G. W. Shrubsole, in
the investigation of this point, may be tabulated as follows : ?—
Water from pei aa Result
River Dee, near Chester . 9300 grs. acted strongly on shells
Wrexham . : : . 4-00 grs. - *
River Dee, near Llanderyel . 0°53 grs. Pe ; -
Trent Canal . : : . 833 gers. no action 3
1J. Lewis, Proc. Bost. Soc. vi. p. 149. 2 Journ. of Conch. v. p. 66.
CHAPTER X
GEOGRAPHICAL DISTRIBUTION OF LAND AND FRESH-WATER
MOLLUSCA — THE PALAEARCTIC, ORIENTAL, AND AUSTRAL-
ASIAN REGIONS
THe Mollusca afford specially valuable evidence on prob-
lems of geographical distribution. This fact is largely due to
their extreme susceptibility to any change in the conditions of
life. Genera which are accustomed to live in a certain temper-
ature and on certain food, cannot sustain life if the temperature
falls or rises beyond certain limits, or if the required food be
not forthcoming. There is therefore a marked contrast between
the Mollusca of the tropics and of the temperate zones, while
different regions in the same latitude, whether within or with-
out the tropics, often show great diversity in their fauna.
Every region is thus characterised by its Mollusca. The Mol-
lusea, for instance, of Australia or of South Africa characterise
those countries quite as much as do the kangaroo and the emu,
the hartebeest and the ostrich; there is nothing like them any-
where else in the world. In the Greater Antilles the Mollusca
stand out beyond all other forms of life as characteristic of the
islands as a whole, and of each separate island in particular.
The geographical distribution of the land and fresh-water
Mollusca must be considered quite apart from that of the marine
Mollusca. The sea offers no such serious barriers to the spread
of the latter as the land does to the spread of the former. If we
were to journey to the Azores, and turn our attention to the
land-snails, we should find them almost wholly peculiar, while
amongst the sea-shells we should recognise many as occurring
also on our southern coasts, and few that were different from
those of the Mediterranean. The marine Mollusca of the Sand-
277
278 LOCALISATION OF GENERA AND SPECIES CHAP.
wich Islands, in spite of the enormous intervening distance, are
not very different from those of Natal, but the land Mollusca of
the two countries are as widely different as is possible to imagine.
Land Mollusea are, as has been remarked, fettered to the soil.
Quadrupeds, birds, fishes, and reptiles are provided with organs of
motion which enable them to overpass barriers of various kinds.
Even plants, although themselves incapable of motion, may be
conveyed in every direction by means of seeds, which are either
wafted by the wind or adhere to the skin of animals. But the
Mollusca have no such regular means of transport, and are, in a
large number of instances, limited to districts of a certain char-
acter of soil, or producing certain kinds of vegetation.
The localisation, both of genera and species, occurs all over
the world. The genus Achatinella, which is pecular to the
Sandwich Islands, is found there in a profusion of species. It
lives in the mountain valleys which radiate from the central
ridge of each island, and each valley is characterised by its own
peculiar set of species. The great carnivorous Glandina is
restricted to Central America and the adjacent parts of the two
continents, with one or two species in Southern Europe. Bulimus
proper is restricted to South America; Achatina to Africa south
of the Sahara; ZYornatellina to the Pacific Islands; Cochlostyla
to the Philippines; Cylindrella and Bulimulus are peculiar to
the New World; Buliminus, Nanina, Scarabus, and Cassidula to
the Old.
Extreme cases of this restriction of habitat sometimes occur.
Thus Limnaea involuta is found only in a single small mountain
tarn in Ireland; Clausilia scalaris along a narrow strip of lime-
stone in Malta; Strophia nana is confined to a few square rods
on an island that is itself a mere dot in the Caribbean Sea; the
genus Camptonyx occurs only in the neighbourhood of Mt. Girnar,
in Gujerat; and Lantzia in moss on the top of a mountain in
Bourbon.
Attempts to colonise snails in strange localities have usually
resulted in failure, especially when the attempt has involved
serious changes of environment. The common Cochlicella acuta
of our coasts resists all endeavours to establish it beyond a cer-
tain distance from the sea. Snails brought from the Riviera and
placed under almost similar conditions of climate on our own
southern coasts have lived for a while, but have very rarely taken
x ARTIBICIAL, GRANSPORT OF SPECIES 279
permanent root. Mr. H. W. Kew? has collected a good many
of these attempts to acclimatise species, the general success of
which seems to depend almost entirely on a restoration of the
old conditions of life.
At the same time there are certain species which exhibit a
curiously opposite tendency, and which seem capable of flour-
ishing in almost any part of the world, and under the most
varied surroundings. Our own common garden snail (Helix
aspersa) is a Striking instance of this adaptability to new condi-
tions. It has been established, by art or by accident, in Nova
Scotia, Maine, South Carolina, New Orleans, California, Mexico
city, Cuba, Hayti, Cayenne, Brazil, Valparaiso, Cape Town, the
Azores, St. Helena, Mauritius, Loyalty Islands, and Australia.
The great Achatina fulica of East Africa has been established
first in Mauritius, and from thence has been carried to the
Seychelles and Calcutta. Helix lactea,a common Mediterranean
species, has been carried to Teneriffe and Montevideo; Helix
similaris, whose fatherland is Eastern Asia, has been transported
to Mauritius, Bourbon, West Africa, West Indies, Brazil, and
Australia; Hnnea bicolor (Eastern Asia) to India, Bourbon,
Mauritius, West Indies; Stenogyra decollata (Mediterranean
basin) to South Carolina; S. Goodallii (West Indies) to British
pineries ; Helix Hortensis to New Jersey. Seven common Eng-
lish species (Limax gagates, Hyalinia cellaria, H. alliaria, Helix
aspersa, H. pulchella, Pupa umbilicata) have become naturalised
in St. Helena,? and as many as nineteen in Australia.
Cases of artificial transport of this kind are readily detected ;
they follow the lines of trade. The snails themselves or their
ova have been accidentally enclosed with plants or mould, or
have adhered to packing-cases, or to hay and grass used in pack-
ing. Thus they constitute no disturbance to the general rule of
the persistent localisation of species and genera, and there is little
fear that the evidence which the geographical distribution of the
Mollusca brings to bear upon the general problems of distribution
will be confused by any intermixture of fauna naturally distinct.
Land Mollusca: Barriers to Dispersal. — The chief natural
barriers to dispersal are extremes of temperature, the sea,
mountain ranges, and deserts. Rivers, however large, seem of
1 The Dispersal of Shells, pp. 182-195. 2K. A. Smith, P.Z. 8. 1892, p. 259.
8C. T. Musson, Proc. Linn. Soc. N. S. Wales (2), v. p. 883.
280 BARRIERS TO DISPERSAL CHAP.
little effect in checking dispersal. There is no appreciable
difference between the land Mollusca north and south of the
Ganges, or north and south of the Amazon. Living snails, or
their ova, are no doubt transported from one bank to another on
floating débris of various kinds. The barrier offered by the sea
is obvious, and at first sight appears insurmountable; but the
facts with regard to oceanic groups of islands lke the Azores
and Canaries (see p. 297) show that even a stretch of salt water
many hundred miles in breadth may be ineffectual in preventing
the dispersal of Mollusca.
Mountain ranges, provided they are too high to be scaled,
and too long to be turned in flank, offer a far more effective
barrier than the sea. Every thousand feet upward means a fall
of so many degrees in the mean temperature, and a change,
more or less marked, in the character of the vegetation. There
is generally, too, a considerable difference in the nature of the
climate on the two sides of a great mountain range, one side
being often arid and cold, the other rainy and warm. The
combined effect of these influences is, as a rule, decisive
against the dispersal of Mollusca. Thus the Helices of Cali-
fornia are almost entirely pecular; one or two intruders from
states farther east have succeeded in threading their way
through the deep valleys into the Pacific provinces, but not a
single genuine Californian species has been able to scale the
heights of the Cascade Mountains. The land Mollusca of India
are numbered by hundreds; not one penetrates north of the
Himalayas. According to Mr. Nevill,! the change from the
Indo-Malayan to the so-called European molluscan fauna at
the northern watershed of the Kashmir valley is most abrupt
and distinct; in two days’ march northward, every species is
different. Ranges of inferior altitude, such as the Pyrenees,
the Carpathians, or the Alleghanies, may be turned in flank as
well as sealed, and we find no such marked contrast between
the Mollusca on their opposite sides.
The most effective barrier of all, however, is a desert. Its
scorching heat, combined with the absence of water and of
vegetable life, check dispersal as nothing else can. The distri-
bution of the Mollusca of the Palaearctic Region is an excellent
instance of this. Their southern limit is the great desert which
1 Scient. Results Sec. Yarkand Exped. “ Mollusca,’’ pp. 1-16.
x BARRIERS TO DISPERSAL 281
stretches, with scarcely a break, from the west coast of Africa
to the extreme east coast of Asia. The Mediterranean offers no
effectual barrier; shells of southern Europe are found in pro-
fusion in Morocco, Tunis, and Egypt, while all through Siberia
to the extreme of Kamschatka the same types, and even the
same species, of Mollusca occur.
A detailed examination of the means, other than voluntary,
by which Mollusca are transported from one place to another
hardly comes within the scope of this work. Ocean currents,
rivers, floods, cyclonic storms of wind, birds, and even beetles
and frogs, play a part, more or less considerable, in carrying
living Mollusca or their ova, either separately or in connexion
with floating débris of every kind, to a distance from their
native home. Accidental locomotion, of one or other of these
kinds, combined with the well-known tenacity of hfe in many
species (p. 87), may have contributed to enlarge the area of dis-
tribution in many cases, especially in the tropics, where the
forces of nature are more vigorous than in our latitudes. The
ease with which species are accidentally spread by man increases
the probability of such cases occurring without the intervention
of human agency, and numbers of instances may be collected of
their actual occurrence.)
A point, however, which more concerns us here is to remark
on the exceedingly wide distribution of the prevailing forms of
fresh-water Mollusca. It might have been expected that the
area of distribution in the fresh-water forms would be greatly
restricted, since they cannot migrate across the land from one
piece of water to another, and since the barriers between pond
and pond, lake and lake, and one river system and another are,
as far as they are concerned, all but insuperable. We might
have expected, therefore, as Darwin and Wallace have remarked,
to find a great multiplicity of species confined to very restricted
areas, since the possibility of communication with the parent
stock appears, in any given case, to be so exceedingly remote.
As is well known, the exact reverse occurs. The range, not
merely of genera, but even of individual species, is astonishingly
wide. This is especially the case with regard to the Pulmonata
and Pelecypoda. The genera Limnaea, Planorbis, Physa, An-
eylus, Unio, and Cyclas are world-wide. Out of about ten genera
1 Mr. H. W. Kew, The Dispersal of Shells, has brought together a very large series.
282 WIDE DISTRIBUTION OF FRESH-WATER MOLLUSCA _ cuHap.
of fresh-water Mollusca in New Zealand, one of the most isolated
districts known, only one is peculiar. In South Africa and the
Antilles no genus is peculiar. In the latter case, this fact is
remarkable, when we consider that the same sub-region has at
least ten peculiar genera of operculate land Mollusca alone.
To give a few instances of the distribution of particular
Species : —
LTimnaea stagnalis L. occurs in the whole of Europe, and
northern Asia to Amoorland, Turkestan, Afghanistan, North
Persia, and Kashmir; Greenland, North America from the
Atlantic to the Pacific, and from North Canada and British
Columbia as far south as Texas. The distribution of L. peregra
Miull., LZ. truncatula Miull., and LZ. palustris Mull. is almost
equally wide.
Planorbis albus occurs in the whole of Europe, and northern
Asia to Amoorland, Kamschatka, and Japan; Turkestan, the
Altai-Baikal district, Alaska and Greenland, North Canada, and
the whole of eastern North America.
The distribution of Anodonta anatina L., Cyclas cornea L.,
and Pisidium pusillum Gmel. is almost equally wide.
It is evident that the accidental means of transport mentioned
above are insufficient to account for the facts as we find them ;
we are therefore compelled to seek for further explanation.
Anything in the nature of a current furnishes a ready means
of transport for Mollusca which have obtained a footing in the
upper waters of a river, and there is no difficulty in imagining
the gradual spread of species, through the agency of floods or
otherwise, over a whole river system, when once established at
any point upon it. The feeble clinging power of newly-hatched
Limnaea has often been noticed as contributing to the chances
of their range of distribution becoming extended. Fresh-water
Mollusca, too, or their ova, are exceedingly likely, from their
extreme abundance, to be transported by water-birds, which fly
without alighting from one piece of water to another. Again,
the isolation of one river system from another is, in many
instances, by no means well marked or permanent, and a very
slight alteration of level will frequently have the effect of
diverting the supplies of one watershed into another. When we
know what enormous oscillations in level have taken place over
practically the whole surface of the globe, we can recognise the
x ATTEMPTS AT EXPLANATION 283
probability that the whole river system of the earth has been
mixed up and reconstructed again and again, with a very
thorough blending of adjacent fauna.
It is possible that the very uniform conditions under which
fresh-water Mollusca live may have something to do with the
uniformity of their distribution and the comparative sameness
in their development. There can scarcely be any question that
the environments of fresh-water species are in themselves less
varied and less liable to fluctuation than those of species whose
home is the land. Water is very like water, all the world over;
it may be running or motionless, warm or cold, clear or muddy,
but the general tendency is for it to be free from extremes of
any kind. Even if the surface water of a lake or river freezes,
or becomes unusually hot, there is generally plenty of water ata
lower stratum which maintains a less extreme temperature, and
to which creatures can retire on the first symptoms of a change.
From this two results will follow. Not only will the inhabitants
of a piece of water not be inclined to vary much from the type,
since their whole surroundings, food, etc., continue very much
the same, but, if transported by any accident or cataclysm else-
where, they will be exceedingly likely to arrive at a place which
closely resembles their former home in all essentials. Thus
the tendency for new types to be formed would be constantly
checked, or rather would very seldom arise.
Mr. Belt, while recognising the importance of changes of
level as affecting the distribution of fresh-water species, appears
to regard the operations of such changes from a rather different
point of view to that described above. “I think it probable,”
he writes, “ that the variation of fresh-water species of animals
and plants has been constantly checked by the want of continuity
of lakes and rivers in time and space. In the great oscillation
of the surface of the earth, of which geologists find so many
proofs, every fresh-water area has again and again been de-
stroyed. . . . Thus species of restricted range were always
exposed to destruction, because their habitat was temporary and
their retreat impossible, and only families of wide distribution
could be preserved.”
The terrestrial surface of the globe has been divided, as indi-
cating the facts of geographical distribution, into six regions —
1 The Naturalist in Nicaragua, p. 304 f.
284 REGIONS OF DISTRIBUTION CHAP.
the Palaearctic, Oriental, Australasian, Ethiopian, Nearctic, and
Neotropical. To these is sometimes added a seventh, the Neant-
arctic, consisting of Chili and Patagonia (and certain islands of
the south Atlantic); but since the Mollusca of Chili unmis-
takably form a part of the Neotropical fauna, it seems hardly
worth while to recognise a separate region for those of the
extreme south of South America, which have no peculiar char-
acteristics.
In certain points the exact limits of these regions, as indi-
cated by the Mollusca, will probably not correspond to those
which are marked out by other zoological classes. Wallace’s
line, for instance, does not exist, as far as the Mollusca are
concerned.
These regions may be further subdivided into sub-regions,
thus : —
Regions Sub-regions Regions Sub-regions
Septentrional / Central African
Palaearctic / Mediterranean Ethiopian { South African
| Central Asiatic | Malagasy
Oriental ; pao ay Nearctic | pag
| Chinese Californian
/ Antillean
Papuan Central American
Australasian { Australian Neotropical / Colombian
| Polynesian | Brazilian
_ Chilian
A. The Palaearctic Region
The southern boundary of this region is the northern limit of
the African Sahara, the Mediterranean forming no break what-
ever in its continuity. In Asia this boundary is less well
marked, but roughly corresponds to the southernmost of the vast
ranges of mountains which border the great tablelands of central
Asia. Across Africa the line of desert is well defined; but in
the north-east, as the desert approaches more nearly to the sea,
the African extent of the region is correspondingly narrowed
until it becomes little more than a strip of coast land, scarcely
widening even in Lower Egypt. On the Morocco coast, Palae-
arctic land forms penetrate as far south as Cape Nun At
its eastern extremity the line becomes less well defined, but
1 Morelet, Journal de Conch. 1875, p. 194.
x THE PALAEARCTIC REGION 285
probably proceeds along the snowy mountains west of Setchouan,
the Pe-ling and Tan-sia-shan ranges, so as to include all the
high ground of Thibet and of the upper waters of the Hoang-ho,
and ultimately reaches its eastern limit at some point on the
shores of the Sea of Japan.
The region thus includes all Europe, Africa north of the
Sahara, with the Atlantic islands (the Azores, Canaries, etc.),
North Arabia, Asiatic Turkey, the greater part of Persia,
Afghanistan, Thibet, all Asiatic Russia, and a very large portion
of the Chinese empire.
The principal characteristics of the region as a whole are: —
(1) The rich development of Helix, Arion, Limax, Buliminus,
and Clausilia.
(2) The comparative absence of land operculates (see map,
Frontispiece ).
(8) The uniform character of the fresh-water fauna.
It is in the southern portion of the region that Helix Gn the
sub-genera Macularia, Iberus, Pomatia, and Xerophila) and
Buliminus (Zebrina, Chondrula, Ena) attain their maximum.
In the north, Frutictcola is the characteristic group; in the
mountainous districts of the south-east, Campylaea, with
Clausilia. The Arionidae have their head-quarters in the
damp and warm regions of western Europe, but are rare in
the south. They only approach the Mediterranean coast in
Algeria, near Gibraltar, and in the region between the base of
the Pyrenees and the Maritime Alps, and are very poor in
species throughout Italy and Sardinia. They are absent from
almost the whole of northern Africa, the Mediterranean islands
(except Sardinia), the whole Balkan district, the Crimea,
Caucasus, and western Asia.
The uniformity of the fresh-water fauna is disturbed only
in the extreme south. A few species of Melanopsis, with Nerv-
tina, occur in southern Spain and Austria, Galicia, and southern
Russia, while a Melania or two (absent from Spain) penetrate
the south-eastern parts of Europe as far as Germany. Cyrena
begins to replace Cyclas in southern Russia and the Caucasus.
The Palaearctic region falls into three sub-regions : —
(1) The Northern or Septentrional Sub-region, ¢.c. the dis-
1 Pollonera, Boll. Mus. Zool. Torino, v. 1890, No. 87.
286 SUBDIVISIONS OF THE PALAEARCTIC REGION CHAP.
trict north of the line formed by the Pyrenees,! Alps, Carpathians,
and which, passing to the northward of the Aralo-Caspian district,
follows the great central mountain range of Asia until it reaches
the Sea of Japan, perhaps somewhere in the neighbourhood of
Vladivostok.
(2) The Mediterranean Sub-region, 7.e. the countries border-
ing on the Mediterranean, the Black and Caspian Seas, with the
Atlantic Islands.
(3) The Central Asiatic Sub-region, z.e. Turkestan, Afghan-
istan, Thibet, and probably the districts of Mongolia and
Manchuria.”
(1) The Septentrional Sub-region has been divided by some
writers into two provinces, the European and the Siberian.
There seems, on the whole, but little occasion to separate off
northern Asia, the characteristic of which is, as will be seen
below, rather the gradual disappearance, as we proceed eastward,
of European species and genera, than the development of any
new and peculiar groups. The remarkable fauna of Lake Baikal
stands apart, not only from European, but also from the Siberian
types occurring in its immediate neighbourhood.
On the whole, the Septentrional Sub-region is poor in species
except those which inhabit fresh water. This fact is probably
due to the extreme vicissitudes of temperature which prevail, and
it is interesting to notice that the number of land Mollusca
appears to touch its lowest point in districts where the annual
range of temperature is greatest. On the other hand, in the
western portions of the region, where the climate is moist and
temperature more equable, the Mollusca are considerably more
abundant and varied.
The line which separates the Septentrional from the Mediter-
ranean Sub-region must of necessity be very roughly drawn, and
stragglers from the south will be found to make their way north-
ward, and vice versd, under favouring circumstances of tempera-
ture and geological formation. Jordan has noticed ? that species
1 South and south-western France, however, belong to the Mediterranean
Sub-region.
2'The coast-line of north-east China, including Corea and Japan to north
Niphon, is much more definitely tropical than the adjacent inland districts. The
coast-line, therefore, must be placed in the Oriental Region, while the inland
districts belong to the Palaearctic Region.
3 Biol. Centralbl. ii. p. 208.
% CIRCUMPOLAR SPECIES 287
which in southern countries are not confined to any particular
quality of soil are in more northern latitudes found only on
limestone, which absorbs more heat than other formations. Con-
versely, the higher elevations of the Alps, Pyrenees, and even
Carpathians are like islands in a sea, and support a thoroughly
northern fauna, quite strange to that of the plains below.. Thus
Helix harpa Say, a completely boreal shell, which is at home in
Canada, Sweden, Lapland, and the Amoor district, is found on
the Riffel Alp, at a height of 6000 feet.t Vertigo arctica Wall.,
a species abundant in Lapland, North Siberia, Iceland, and Green-
land, occurs on the high Alps of the Tyrol.
Circumpolar Species. — A certain number of species are com-
mon to the extreme north both of the Palaearctic and Nearctic
regions, and are, in fact, cireumpolar. The number of these
species, however, is so small, not exceeding about 40: species
(=16 genera), that it seems hardly worth while creating a spe-
cial sub-region for their reception, particularly as no genus is
peculiar. At the same time the fact is instructive as illustrating
the close connexion of the northern districts of the two regions,
a connexion which was no doubt more intimate in recent geolog-
ical times than it is now.
The circumpolar genera are as follows. The list decisively
sets forth the superior hardiness of the fresh-water as compared
with the land genera: —
sp. Physa..- . lL sp,
so Anodonta 1 ,,
Uniroy 2 sk x,
$5 Pigidium ..: ‘1. ;,
Valvata .1sp. Helix . .4 sp. Succinea .
Bithynia . 1 ,, Patulaies:s 2. -, Limnaea .
Witrina «; 1”, Pupa o 5 Planorbis.
Hyalinia . 4 ,, Cionella .1 ,, Aplecta
— OU aT
Great Britain. —'There are in all about 130 species — 83
land, 46 fresh-water; Zimnaea involuta (mountain tarn near
Killarney) appears to be the only peculiar species. There are
11 Hyalinia, 5 Arion, and 25 Helix, the latter belonging princi-
pally to the sub-genera Xerophila, Tachea, Trichia, and Fruti-
cicola. Three Testacella are probably not indigenous, but are
now so well established as to reckon in the total. Of the four
Clausilia two reach Ireland and one Scotland; two do not occur
north of the Forth. There are only two land operculates, one of
which ( Cyclostoma elegans) occurs in Ireland but not in Scotland,
while the other ( Acicula lineata) reaches the southern counties
1 Craven, Journ. de Conchyl. (3) xxviii. p. 101.
288 GREAT BRITAIN — FRANCE CHAP.
of Scotland. Several species, e.g. Helix pomatia, H. obvoluta, H.
revelata, H. cartusiana, H. pisana, Buliminus montanus, are
restricted to the more southern or western counties; Geomalacus
maculosus is confined to a district in south-western Ireland.
The Pleistocene beds of East Anglia contain a number of
species. now extinct in these islands, whose occurrence appears
to indicate a warmer climate than the present. Such are Helix
ruderata, H. fruticum, H. inearnata, Clausilia pumila, Unio
littoralis, Hydrobia marginata, and Corbicula fluminalis.
Scandinavian Peninsula.— From Norway 121 species in all
are recorded, and 148 from Sweden. The milder climate of
Norway allows many species to reach a considerably higher lati-
tude than in Sweden, thus in Sweden Limaxr maximus only
reaches 62°, but in Norway 66° 50’. Similarly Arion hortensis
and Balea perversa only reach 63° and 61° respectively in
Sweden, but in Norway are found as far north as 69° and 67°
50’. Clausilia is represented by 9 species in southern Norway ;
one of these is found north of the Arctic circle. There are 4
Pupa, 9 Vertigo, and 11 Hyalinia, but Helix dwindles to 14, 9 of
which occur north of the Arctic circle. No land operculates
are found; Cyclostoma elegans, however, occurs in Jutland and
Zealand, which practically form a part of this district.
Iceland. — Eleven species, all Scandinavian, occur. These
are Arion 2, Limazx 1, Helix 2 (arbustorum L. and hortensis Mull.,
the latter being found only on the warmer southern coast),
Limnaea 1, Planorbis 1, Pisidium 4.
France. — The northern, central, and eastern districts belong
to this sub-region, while the southern and western, in which an
entirely new element occurs and many northern forms disappear,
belong to the Mediterranean. Thus, for instance, Helix pomatia
L., H. inearnata Mill., H. fruticum Miill., H. cantiana Mont., H.
strigella Drap., H. rufescens Penn., H. plebeta Drap., are not
found in southern France. No detailed enumeration of species
is at present possible, the efforts of a large number of the lead-
ing French authorities being directed to indiscriminate species-
making rather than to the careful comparison of allied forms.
Perhaps the principal difference between the Mollusca of north-
ern France and those of our own islands is the occurrence of two
species of Pomatias. In the more elevated districts of eastern
France (the Vosges, Jura, western Alps), a certain number of
x FRANCE AND GERMANY 289
species occur which are confined to the high grounds of south
central Europe. Among these are Helix holoserica Stud., H.
personata Lam., H. bidens Chem., H. depilata Drap., H. cobresiana
Alt., H. alpina Faure.
The Pleistocene deposits of the valley of the Somme tell the
same tale as those of eastern England, containing as they do
species and even genera whose northern range is now much more
limited. The Eocene fossils from the Paris beds show most re-
markable relationships to genera now existing in the West Indies
and Central America. Others again indicate affinities with India.
Thus we find Ceres, Megalomastoma, and Tudora by the side of
Leptopoma, Faunus, and Paludomus. ,
Germany.— The Mollusca of the plains of northern Germany
are few and not striking, and exhibit littie difference from those
of our own islands. In the mountainous districts of the south
and south-east, a number of new
forms occur, amongst which are 3
species of Daudebardia, a remarkable
carnivorous form, with the general
appearance of a Vitrina; 24 of Clau- /
silia, many Pupa, several Buliminus, ae - ee
3 of the Campylaea group of Helix, _ orifice. (After Pfeiffer.) B, shell
stragglers from the Italo-Dalmatian _ 2” Pir-, 8. Germany.
fauna, and 1 of Zonites proper. Our familiar Helix aspersa is |
entirely absent from Germany. There are only 4 land oper-
culates— Pomatias 2, Acicula 1, Cyclostoma 1, all of which occur
exclusively in the south. SBithynella and Vitrella, two minute
forms of fresh-water operculates akin to Hydrobdia, occur through-
out the district. |
Northern Russia and Siberia.—This vast tract extends from
eastern Germany to the Amoor district. It is exceedingly poor
in Mollusca, and is chiefly characterised by the gradual disap-
pearance, as we proceed eastward, of European species. There
are a few characteristic Siberian Mollusca, closely allied to
European forms, and in the extreme east a new element is
introduced in the appearance of types which indicate Chinese
affinities. The whole district may be regarded as bounded to the
south by a line drawn from Lemberg to Moscow, and thence to
Perm; passing south of the Ural mountains, it includes the
whole basins of the rivers Obi, Yenesei, and Lena, coinciding with
VOlan TE U
290 NORTHERN RUSSIA AND SIBERIA CHAP.
the vast mountain ranges which terminate to the north the table-
land of central Asia, at the eastern extremity of which it dips
sharply southwards, so as to include the Amoor basin and Corea.
All the larger Helices are wanting, and no land operculates
occur. Helix arbustorum L., H. nemoralis Miull., H. lapicida L.,
H. aculeata Mill., and Hyalinia nitidula Drap., do not appear to
occur east of the Baltic; Arion fuscus Mull., Helix strigella Drap.,
Buliminus obscurus Mill., Clausilia laminata Mont., C. bidentata
Bttg., C. plicatula Drap., Viviparus fasciatus Mull., and Neritina
fluviatilis L., do not pass the Urals.
In the Obi district (West Siberia) a further batch of European
species find their easterly hmit. Among these are Helix hispida
L., Bithynia tentaculata L., Vivipara vivipara L., Pisidiwm amni-
cum Mull., and Unio tumidus Retz. A few distinctly Siberian
species now appear, e.g. Ancylus sibiricus Gerst., V ‘alvata sibirica
Midd., and Vitrina rugulosa Koch.
The following are among the European species which reach
eastern Siberia: Hyalinia nitida Mill., Succinea oblonga Drap.,
Planorbis vortex L., spirorbis L., marginatus Drap., rotundatus
Poir., fontanus Light., Valvata piscinalis Mull., Bithynia ventri-
cosa Leach, and Anodonta variabilis Drap. Here first occur such
characteristic species as Physa sibirica West., P. aenigma West.,
Helix pauper Gld., H. Stuxbergi West., H. Nordenskiéldi West.,
Planorbis borealis Lov., Valvata aliena West., Cyclas nitida Cless.,
and C. levinodis West. In the Amoor district a decided Chinese
element makes its appearance in a few hardy forms which
have penetrated northward, e.g. Philomycus bilineatus Bens.,
and a few each of the Fruticicola (Chinese) and Acusta groups
of Helix. Out of 53 species, however, enumerated from this
district, as many as 33, belonging to 18 genera, occur also in
Great Britain.
Lake Baikal. —The Mollusca of Lake Baikal exhibit distinct
characteristics of their own, which seem to indicate the long-
continued existence of the lake in its present condition.
Several entirely peculiar genera occur, which are specialised
forms of Hydrobia,e.g. Baikalia, Liobaikalia, Gerstfeldtia, Dybow-
skia, and Maackia; Benedictia alone extends to the basin of
the Amoor. Choanomphalus, another peculiar and ultra-dextral
(p. 250) genus belonging to the Limnaeidae, appears to be related
to the West American Carinifex.
x SPAIN AND NORTHERN AFRICA 29I
(2) The Mediterranean Sub-region is divided into four
provinces: (a) The Mediterranean province proper; (0) the
Pontic; (c) the Caucasian; and (d) the Atlantidean province.
(a) The Mediterranean province proper is best considered
by further subdividing it, with Fischer and others, into separate
districts, each of which has certain pecuhar characteristics.
G) The Mispano-Algerian district includes the greater part
of the Iberian peninsula, the Balearic Islands, and northern
Africa from Morocco to Tunis. The extreme western parts of
these districts, including West Morocco, Portugal, Asturias, and
south-west France, under the influence of the moist climate
caused by the Atlantic, show some pecuhar features which, in
the view of some, are sufficient to justify their separation from
the rest of the Hispano-Algerian portion. Among these is a
marked development of the slugs, Testacella, Arion, and Geoma-
lacus, the latter of which occurs even in south-western Ireland.
Spain. — The principal features are the development of the
Macularia, Iberus, and Gonostoma groups of Helix, and the
Fia. 194. — A, Parma-
cella Valenciensit
W. ‘and! Be. xz.
(After Moquin-
Tandon.) A’, shell
of the same, natu-
ral size.
occurrence of the remarkable slug Parmacella, which is found
in many other parts of the sub-region, and extends eastward as
far as Afghanistan. CUausilia has but few species, mostly in the
north. There are four species of land operculates, one of which
is referred to a genus (T7udora) now living only in the West
Indies, but which occurs in the Eocene fossils of the Paris
basin. In the south there are several species of Melanopsis and
Neritina.
The States of Northern Africa have a thoroughly Mediterra-
nean fauna, whose facies on the whole shows rather more affinity
to Spain than to Sicily. The Helices of Morocco and Algeria
belong to the same groups as those of southern Spain. Many
are of a dead white colour, the better to resist the scorching
effect of the sun. Ferussacia is abundant, Geomalacus and Par-
os
292 NORTHERN AFRICA AND THE SAHARA CHAP.
macella are represented by a single species each, and there is one
Olausilia. According to Kobelt,! the original land connexion
between southern Spain and Morocco must have been much
more extensive than is usually assumed, and probably reached
at least to the meridian of Oran and Cartagena. The Mollusca
of Oran and Cartagena are, according to him, much more closely
related than those of Oran and Tangier, or those of Cartagena
and Gibraltar, but at Cartagena some species, which are charac-
teristic of the Mediterranean coasts from Syria westward, dis-
appear, are absent from the rest of Spain and from Morocco, but
reappear on the south-western coasts of France. These species
may possibly have pushed along that arm of the sea which, when
the Straits of Gibraltar were closed as far as the latitude of Oran
and Cartagena, united in comparatively recent times the Bay of
Biscay with the Gulf of Lions.
The following genera, which do not occur in Spain, have
probably spread into northern Africa as far as Algeria, vza Sicily
and Tunis, namely, Glandina (1 sp.), Daudebardia (1 sp.),
Pomatias (2 sp.). Tunis shows strong traces of Sicilian influ-
ence, and Kobelt found a colony of snails, of Sicilian affinities,
as far west as Tetuan.
The Sahara. — The Algerian Sahara contains, in many places,
a sub-fossil Molluscan fauna which appears to show that the
district has, in quite recent times, undergone a gradual desicca-
tion. The species are mainly fresh-water, including Melania,
Melanopsis, and Corbicula, with here and there valves of Cardium
edule, and indicate, on the whole, an affinity with recent Egyp-
| tian, rather than North African
species. Itis probable that a vast
series of tangs, or brackish-water
lakes, once stretched along this
region, and were ultimately con-
nected with the sea somewhere
A B between Tunis and Egypt.
Fic. 195.— Characteristic shells of S. :s A ork le
France: A, Helix (Macularia) ni- G1) Southern France. The
ciensis Fér.; B, Leucochroa candi- Southern portion of France bor-
ecg Drap. dering on the Mediterranean
contains many species, especially of Helix, which do not occur in
the centre and north. Amongst these are —
1 Jahrb. Deutsch. Malak. Gesell. viii. p. 278.
x ITALY “AND SICIEy 293
Leucochroa candidissima Drap. | Helix ciliata Ven.
Hyalinia olivetorum Gmel. » explanata Mull.
Zonites algirus L. »» apicina Lam.
Helix rangiana Desh. 55 cespitum Drap.
5 serpentina Fer. » Lerverii Mich.
» niciensis Fér. 5 pyramidata Drap.
» splendida Drap. , trochoides Poir.
» vermiculata Mill. Ferussacia folliculus Gron.
» melanostoma Drap. Rumina decollata L
»» aperta Born. Pupa megacheilos C. and J.
Several species of fresh-water Hydrobia (Bithynella) occur.
The district, on the whole, unites certain
characteristics derived from northern Italy
with those of eastern Spain.
Gii) The Jtalo-Dalmatian district in-
cludes Italy and the neighbouring islands
(Corsica, Sardinia, Sicily, Malta), and the
regions at the head and north-eastern shores
of the Adriatic (Carinthia, Carniola, Croatia, <—
and Dalmatia), the line which separates pie, 196.— Helix (Poma-
these latter districts from the fauna of south- 4) aperta L., 5.
: ; . : France, showing epi-
ern Austria, Bosnia, and Servia being very phragm.
difficult to define.
Italy, with the neighbouring islands, has a rich molluscan
fauna. In the sub-Alpine districts of northern Italy the promi-
nent Helix groups are Campylaea, Pomatia, and Anchistoma,
which in the south are generally replaced by Jberus, which here
attains its maximum development. Large Ayalinia are abun-
dant in the north, and Pomatias and Clausilia are frequent all
Fic. 197. — Helix (Campylaca) zonata Fic. 198. — Helix (Iberus)
Stud., Piedmont. strigata Miill., Florence.
along the Apennines. Sicily has about 250 species, half of
which are peculiar. Helices of the Ierus type abound, but
Campylaea is reduced to two species. Many peculiar forms of
Clausilia occur, especially a latticed type of great beauty. Ferus-
294 DALMATIA, EGYPT, AND SYRIA CHAP.
sacia and Pupa are well represented, and there are one each of
Glandina and Daudebardia.
Dalmatia and the adjacent districts are chiefly remarkable
for the rich development of Clausilia, which here attains its
maximum (nearly 100 species). The Campylaea section of
Helix is represented by its handsomest forms,
many of which are studded with short hairs.
Here too is the headquarters of Zonites
proper, which stretches westward as far as
Provence, and eastward to Asia Minor; and
also of the single European Glandina, which
has a similar eastward range, but spreads
7 _. westward through Italy and Sicily to
Fie. 199.— A, Clausiliu : : ;
hh aS Ben., Algeria, not occurring in southern France.
Sicily ; B, Clausilia The land operculates are chiefly repre-
macarana Zieg., Dal- :
matia: B', clausilium Sented by Pomatias, and among the fresh-
of same. water operculates are a Melania and a
Lithoglyphus, the latter having probably spread from the basin
of the Danube.
(iv) The EHgypto-Syrian district extends along the south-
eastern shores of the Mediterranean from Tripoli to North Syria,
and eastward to the Euphrates valley. Lower Egypt alone
belongs to this portion, the fauna of Upper Egypt being of an
entirely tropical character, and belonging to the Ethiopian
Region.
Lower Egypt. — The Mollusca of Lower Egypt stand in the
unique position of belonging, half to the Palaearctic, and half to
the Ethiopian Region. The land Mollusca are of a distinctly
Mediterranean type, while the fresh-water, directly connected as
they are by the great highway of the Nile with regions much
farther south, contain a large admixture of thoroughly tropical
genera (Ampullaria, Lanistes, Melania, Cleopatra, Corbicula,
Cyrena, Iridina, Spatha, Mutela). The Helices, which are not
numerous, are rather a mixture of circum-Mediterranean species
than of a specially distinctive character. H. desertorum, how-
ever, belonging to the group Hremophila, is characteristic.
There is a single Parmacella, but the physical features of the
country are unfavourable to the occurrence of such genera as
Clausilia, Pupa, Hyalinia, and the land operculates.
Syria.— The Mollusca, especially in the more mountainous
x THE PONTIC PROVINCE 2905
regions of the north, are much more varied and numerous than
those of Egypt. Clausilia is again fairly plentiful, and the
Helicidae are represented by some striking
forms of the sections Levantina, Pomatia,
and Nummulina. Leucochroa has several
curious types with a constricted aperture,
and the Agnatha are represented by Libania,
a peculiar form of Daudebardia. A promi-
nent feature is the occurrence of a number
of large white Buliminus of the Petraeus
section (Fig. 200). Land operculates appear
to be absent, but Melanopsis and Neritina 2 eee plans
are abundant. The Dead Sea contains no Oliv., Beyrout; B,
Mollusca, but Lake Tiberias has a rich fauna, ea ee, hee
including the above-mentioned genera, with _ Roth., Palestine.
a Corbicula and several Unie.
Upper Mesopotamia appears to possess a mixture of Syrian
and Caucasian forms, including a Parmacella. Lower Mesopo-
tamia has an exceedingly poor land fauna, but is comparatively
rich in fresh-water species, the growing eastern character of
which is shown by the occurrence of several Corbicula and
Pseudodon, and of a Neritina of a distinctly Indian type.
(6) The Pontic province extends from Western Austria to
the Sea of Azof, and includes Austria, Hungary, Roumania, the
Balkan peninsula (so far as it does not form part of the Mediter-
ranean sub-region ), the islands of the Greek Archipelago, south-
ern Russia and the Crimea, and Asia Minor. It thus practically
corresponds to the whole Danube basin, together with the lands
bordering on the Black Sea, except at the extreme east, which
belongs to the Caucasian sub-region. Fischer separates off
Greece, Asia Minor (except the northern coast-line), and the
intervening islands, with Crete and Cyprus, as constituting a
portion (Hellado-Anatolic) of the Mediterranean sub-region
proper. These districts, however, appear to possess scarcely
sufficient individuality to warrant their separate consideration.
A prominent characteristic of the Pontic Mollusca is the
great abundance of Clausilia and Buliminus. In the islands
east and west of Greece Clausilia forms a large proportion of the
fauna, each island, however small, possessing its own peculiar
forms. The Helices belong principally to the groups Campylaea
296 THE CAUCASUS AND THE CASPIAN SEA CHAP.
(which is very abundant in Austro-Hungary), Pomatia (Greece
and Asia Minor), and Anchistoma. Macularia is comparatively
scarce, but is represented in Greece by one very large form
(Codrington Gray). Zonites proper has its metropolis in this
sub-region, and the Danube basin contains one or two species
of Melania and Lithoglyphus. Buliminus is abundant through-
out the sub-region, in the sub-genera Zebrina, Napaeus, Mastus,
and Chondrula. Several striking forms of Zebrina (Ena) are
peculiar to the Crimea.
(c) The Caucasian Province. —The limits of this province
can hardly be exactly defined at present. It appears, however,
to include the whole line of the Caucasus range, Armenia, and
North Persia.
The land Mollusca are abundant and interesting. Among the
carnivorous genera are four species of Daudebardia, a Glandina,
and three peculiar forms of naked slug, Pseudomilax, Trigono-
chlamys, and Selenochlamys. There is a single Parmacella, the
same species as the Mesopotamian, and a good many forms of
Limax. Vitrina and Hyalinia are well represented, and the pre-
dominant groups of Helix are Huloto, Cartusiana, Xerophila, and
Fruticocampylaea, the last being peculiar. Clausilia and Pupa
are rich in species, together with Buliminus of the Chondrula
type. One Clausilia of the Phaedusa section, together with a
Macrochlamys (Transcaspian only), a Corbicula, and a Cyclotus,
show marked traces of Asiatic affinity. There is one species
each of Acicula and Cyclostoma, and one of Pomatias.
The Caspian Sea, like Lakes Baikal and Tanganyika, is dis-
tinguished by the possession of several remarkable and peculiar
genera. The sea itself, the waters of which are brackish, is 80
feet below the level of the Black Sea, and is no doubt a relict of
what formed, in earlier times, a very much larger expanse of
water. Marine deposits containing fauna now characteristic
of the Caspian, have been found as far north as the Samara bend
of the Volga. It is probable, therefore, that in Post-plocene
times an arm of the Aralo-Caspian Sea penetrated northward up
the present basin of the Volga to at least 54° N. The Kazan
depression of the Volga (55° N.) also contains characteristic
Caspian fossils... According to Brusina,? the Caspian fauna,
1 Netchayeff, Kazan Soc. Nat. xvii. fasc. 5.
2 Fauna der Congerien-Schichten, p. 142.
x MADEIRA AND THE CANARIES 207
_—
as a whole, is closely related to the Tertiary fauna of southern
Europe.
Twenty-six species of univalve Mollusca, the majority being
modified forms of Hydrobia, have been described from the Caspian,
namely, Wicromelania (6), Caspia (7), Clessinia (3), Nematurella
(8), Lithoglyphus (1), Planorbis (1), Zayrabica (1), Hydrobia (2),
Neritina (2). The bivalves are mostly modified forms of Cardium
(Didacna, Adacna, Monodacna), which also occur in estuaries
along the north of the Black Sea.
pines fm GEOGRAPHICAL DISTRIBUTION
a
GR) oO of the Land Mollusca of the
s
ve EAST INDIAN ARCHIPELAGO
= < The red line marks the 100 fathom line
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95 Longitude E.100 of Greenwich 105 no 5 120 126 180 135
London. Stanso sta
London: Macmillan & Co.
308 MALACCA — SUMATRA
This
islands
which s
panying
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Fis. 207.—
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s- JAVA AND BORNEO 309
It seems not impossible, from the point of view of the land
Mollusca only, that the Sunda Islands may at one time have
stretched much farther into the Bay of Bengal, prolonged, per-
haps, into what are now the Andaman and Nicobar groups,
while Ceylon and the western side of the Deccan, united into
one continuous piece of land, and possibly separated from N, India
by a wide stretch of sea, extended farther eastward in a long
island, or series of islands.
Java, from its Mollusca, does not appear to hold the compara-
tively isolated position which its mammals and birds seem to
indicate. Borneo, on the other hand, is more Siamese than Java
or Sumatra in respect of a group whose metropolis is Siam,
namely, the tubed operculates; for while that section is repre-
sented by 3 species in Sumatra and only 2
in Java, in Borneo it has as many as 19,
Rhiostoma not occurring in the two former
islands atall. Alycaeus, Lagochilus, Pupina,
and Cyclophorus are found throughout, but
Hybocystis (Malacca, 1 sp.) does not quit the
mainland. Borneo is remarkably rich in
land operculates, especially noticeable being
the occurrence (11 sp.) of Opisthostoma
(Fig. 208), a most extraordinary form of
land shell (Ceylon, Siam), of Diplommatina
(17 sp.), and Raphaulus. The occurrence
Fic. 208.—A, Opisthostoma
of a single Papuina (Moluccas eastward) Cookei E. A. Smith,
iS very remarkable. Borneo; B, Opistho-
; : ee stoma grandispinosum
Amphidromus is a genus characteristic G.-A., Borneo. Both
of the great Sunda Islands, attaining its AS.
maximum in Java (12 sp.). The Indian Glessula still has
ohne species each in Sumatra, Java, and Borneo. One species
of Streptazis! occurs in Malacca, but Hnnea (3 sp.) reaches as
far east as Borneo and the Philippines. Parmarion, Helicarion,
Ariophanta, and other groups of the Naninidae are well repre-
1 Streptaxisisaremarkable instance of amainlandgenus. Althoughabundant
in the Oriental, Ethiopian, and Neotropical regions, it never seems to occur on
any of the adjacent islands, except in the case of Trinidad (1 sp.), which is prac-
tically mainland. Omphalotropis, on the other hand, is the exact reverse of
Streptaxis in this respect, occurring all over Polynesia and the Malay Is., as far
west as Borneo, as well as on the Mascarenes, but never, save in a doubtful case
from China, on the mainland of Asia, Australia, or Africa,
310 CELEBES CHAP.
sented. Hemiplecta and Xesta are abundant and large, while the
Rhysota of Borneo contain some huge sinis-
tral forms. hodina is a remarkable form
from Malacca, whose exact generic position
is not yet settled. Clausilia has afew species
on all the islands, the last occurring on
Ternate, and a single Papuina (Moluccas
and N. Guinea) occurs in Borneo.
The Island of Celebes marks the be-
ginning of a distinct decrease in the Indo-
Malay element. The Naninidae lose
eround, in proportion to the Helicidae,
FE MA indents Macrochlamys, for instance, being repre-
perversus L., Java. sented by only one species, and Hemzplecta
by four. Other characteristic genera of
the Indian region dwindle, such as Amphidromus, Clausilia,
the tubed operculates, and Cyclophorus, while Sitala, Kaliella,
Glessula, and Plectotropis disappear altogether. Comparing
the total numbers of Naninidae and Helicidae from Sumatra to
New Guinea, we obtain this interesting result : —
Sumatra Java Borneo Celebes Moluccas N. Guinea
Nanina (all genera) 26 52 51 22 36 40
Helix (all genera) i i 15 14 55 91
It will be noticed that the proportion of Naninidae to Helicidae,
which has been nearly 4 to 1 in Sumatra, falls to 8 to 1in Java,
and rises again to 4 to 1 in Borneo (showing the essentially con-
tinental character of the island); in Celebes it further falls to 3
to 2, while in the Moluceas the scale turns and Heliz has the
advantage by about 8 to 5, and in N. Guinea by more than
2 to 1.
There is the same absence of marked features of individuality
in Celebes as in the islands dealt with above. Not a single
genus is peculiar. The nature of the sea bottom between Borneo
and Celebes, with its indications of a somewhat broad bridge over
an otherwise deep channel of separation, would seem to account
for and suggest the true explanation of the facts as they stand.
At the same time, there are indications of a certain amount of
contrast between N.andS.Celebes. The Indian element, which
constitutes the preponderating majority of the fauna, is common
to north and south alike. But the north part of the island, in
x CELEBES— THE MOLUCCAS snr
which Obba and Obbina occur, shows decided relationship with
the Philippines, while the occurrence of three CAloritis and one
Planispira tend to approximate 8. Celebes rather with the
Moluccas.
The islands eastward of Java, from Bali to Timor Laut and
the Tenimber Is., present no trace of individual peculiarities ;
they simply carry on the Indo-Malay fauna as though along a
great peninsula. Even Timor, surrounded as it is on all sides by
sea of profound depth, shows no sign of possessing even one
peculiar genus. Amphidromus, perhaps the most characteristic
of all Indo-Malay genera, occurs throughout, diminishing in
numbers as we go eastward (Bali, Lombok, and Sumbawa 4 sp.,
Timor 2 sp., Timor Laut 1 sp.), while Plectotropis reaches no
farther than Flores and Timor. The tubed operculates are alto-
gether wanting. In Timor Laut we have Moluccan influence
appearing in 8 Chloritis, and there is one (supposed) Corasia.
Two Helices of a marked Australian type (thagada) occur, one
in Flores, the other on Dama I., south-west of Timor. The con-
figuration of the sea bottom (see map) would lead us to believe
that the north-west coast of Australia once stretched a good
deal nearer to these islands.
The Moluccas, taken as a whole, constitute a transition region
between the Indo-Malay and the Papuan faunas, uniting, to a very
considerable extent, the features of both. They fall into two
well-defined groups. The northern, or Ternate group, consists of
Gilolo (Halmahera), Batchian, and the outlying islands as far
south as and including Obi major. The southern, or Amboyna
group, consists of Buru, Ceram, Amboyna, and the chain of islands
to the south-east of Ceram, as far as, and including the Ké Is.
The Ternate group shows decidedly closer relations with New
Guinea than the Amboyna group. Thus, among the Helices, the
markedly Papuan genus Papuina is represented by T species in
the Ternate group, but by 1 in the Amboyna group. Again, the
Cristigibba section of Planispira, which is a Papuan form, has
4 representatives in the northern group, but only 1 in the
southern. Certain points of connexion with Celebes come out
in the southern group which are wanting in the northern; thus
of Chloritis there are 8 species in Amboyna, 0 in Ternate, 5 in
Celebes.
In the Moluccas the Helicidae, for the first time as we move
312 THE MOLUCCAS CHAP.
eastward from India, gain the ascendancy over the Naninidae,
the numbers being, Heliz 55, Nanina 36. If we take the groups
separately, we find that in the Amboyna group the proportion is
22 to 23, while in the Ternate group it is 383 to 13, an addi-
tional proof that the Amboyna group is far less Papuan than the
Ternate. Of Planispira, the most characteristic sub-genus of
Helix, there are 12 species in the Ternate group, and 5 in the
Amboyna. The section Phania, which contains 4 species of the
finest Helices known, is quite peculiar to the Ternate group.
One species of Obbina, a sub-genus markedly Philippine, occurs
in each group. Several of the Indo-Malay land operculates
(e.g. Ditropis) reach their limit here, and here too we have the
last Clausilia (strangely absent from the Amboyna group).
Amphidromus is not reported on sufficient authority to warrant
its insertion in the list.
Land Mollusca of the Moluccas. (T = Ternate, A = Amboyna! group)
Helicarion . 1A. Cristigibba . JA,4T ‘Paunus . | <= A
Euplecta . . LAr sObbina..<. = LA,? ET. Vivipara. -age 1A
esta #, .-.< | GAYA Phania,..> - 4T Acmella. 2 1A
Macrochlamys 1A Albersia . . oT Diplommatina. 4 A, 2T
Lamprocystis 4A,27T Camaena . 1T £Registoma . . 3
Macrocycloides AA) 6Papuina... © 1A, 77 “Pupmella yas 1A
sitala;. of .. 1A APUpaie. 2 s \. 3 Gallia 2 ae 2A
Kaliella 2 -2~%3,.A,1T Vertigo . . 2A Leptopoma. . 4A,5T
Trochomorpha 38A,3T Clausilia. . 1T Lagochilus . <> Aye
Endodonta . 1A Opeas.. 4A,4T Ditropis sues 3A
Patula .. 1A Subulina. . 1A Cyclotus . . 44768
Plectotropis . 1T = ‘Tornatellina 1A Omphalotropis 3A
Eulota .. 1A Vaginula . 1A. Georissa. . % 1
Chioritis..... SA Melania . .18A,4T ~—Helicnma. «= 645e0
iRigmispira. < 5-4, 122
(d) The Philippine Province. —In the extraordinarily rich
development of their Mollusca, the Philippines form a remark-
able contrast with the poverty of the adjacent Malay islands.
No less than 727 species of land Mollusca alone are known from
the group, amongst which are included some of the finest and
handsomest forms yet discovered. The main features of the
fauna are Indo-Malay, with the addition of a certain Australa-
1The Amboyna group has been much the better explored. Common to both
groups are one sp. each of Kaliella, Trochomorpha, Opeas, Leptopoma, Cyclotus,
Helicina.
x THE, PHILIPPINES 313
sian element, and a remarkable development of individual char-
acteristics.
The principal indigenous feature is the profuse abundance
of the genus Cochlostyla, a group of large and elegant land shells,
partly helicoid, partly bulimoid in shape, many of the species
of which are covered with a curious hydrophanous epidermis.
They are in the main of arboreal habits, living in the tops of the
enormous forests which cover the greater part of the islands.
As many as 247 species, belonging to 15 sub-genera, have been
described.
The distribution of the sub-genera of Cochlostyla on the
Fig. 210. — Cochlostyla (Chry- Fic. 211.— Cochlostyla (Ortho-
sdlis) mindoroensis Brod., stylus) Porteit Reeve, Luzon.
Mindoro, Philippines. x 3.
different islands of the Philippine group affords important
evidence on the geological relation of the islands to one another.
Thus we find Orthostylus and Hypselostyla occurring in the
central islands and 8. Luzon, but not in Mindanao or Mindoro;
we find Chrysalis peculiar to Mindoro, Prochilus to Mindoro
and the Cuyos, Ptychostyla to Luban, all these being sub-genera
of very marked characteristics. Six out of the fifteen sub-genera
are entirely absent from Mindanao, although occurring on the
islands in the immediate vicinity. The little group Tablas-
Romblon-Sibuyan are entirely deficient in certain sub-genera
which occur on the islands surrounding them on all sides.!
1 A. H. Cooke, P. Z. S. 1892, pp. 447-469.
314 THE PHILIPPINES CHAP.
Other forms peculiar to the Philippines are Diaphora, a
section of Ennea with a curi-
ously produced mouth, and
several sub-genera of the
Naninidae ( Vitriniconus, Vit-
rinoidea, Hemitrichia). The
great Rhysota here find their
metropolis. Another very
—— marked group of Helix is
Fic. 212. — Helix (Obbina) rota Brod., Obbina, 19 of the 25 known
Philippines. : - :
species being peculiar.
The Helicidae proper of the Philippines are still held in
check, as in the greater part of the Indian region, by the
Naninidae. The single TZrachia and Plectotropis, and the 2
species each of Plectopylis and Satsuma, indicate affinities with
Indo-China. Further important Indian relationships are seen
in the great Manina and Cyclophorus, which here attain almost
Indian dimensions; in Kaliella (8 sp.), Sitala (2), Clausilia
(1). Among the operculates we still have 1 Alycaeus and 1
Coptochilus. Singularly enough, several Indian genera which
occur here are not found in the intervening islands of Bor-
neo, Sumatra, or Java, e.g. Streptaris, Hypselostoma, Ditropis,
Acmella, and Cyathopoma. ‘The curiously tubed Malay opercu-
lates, Opisthoporus, etc., fail to reach the Philippines proper,
although occurring in Borneo and N. Celebes; one of them.
reaches Palawan. The strikingly Malay genus Amphidromus
reaches Palawan, but no farther (1 sp.), while 2 species reach
Mindanao, and one of these penetrates as far as Bohol and S.
Leyte. Amongst the slugs, Mariaella occurs again only in the
Seychelles, and Zennentia only in Ceylon.
Land and Fresh-water Mollusca of the Philippines
Streptaxis . 1 Hemiplecta . 11 Trochomorpha 21 Papuina 1
Ennea . 10 Hemitrichia .15 Endodonta 1 Phoenicobius . 7
Mariaella 3 Xesta 2 Plectopylis 3 Cochlostyla. 247
Tennentia . 1 Macrochlamys 5 _ Plectotropis 1 Amphidromus. 2
Helicarion . 21 Microcystis 3 Aulacospira 3 Hapalus (?) +
Vitrinopsis 5 Lamprocystis . 17 Pupisoma 1 Hypselostoma. 1
Vitrinoidea 1 Bensonia 4 Satsuma 2 Pupa 4
Rhysota . 17 Vitriniconus . 16 Dorcasia 2 Clausilia 1
Trochonanina 2 Sitala 2 Chloritis . 7 Subulina 5)
Euplecta 28 Kaliella 8 Obbina . 19 Prosopeas 2
x ISLANDS ADJACENT TO THE PHILIPPINES 315
Opeas 4 Melania . . 50 MHargreavesia . 1 Cyathopoma . 5
Geostilbia . 1 Pirena 2 Callia 2 »Cyclotus. =. . 19
Tornalellina 1 Bithynia 1 Pupinella 3 Omphalotropis 3
Succinea 3 Vivipara 7 Helicomorpha 4 Helicina . . 18
Vaginula 2 Ampullaria 5 - .Coptechilus- .° 1 &Georissa 7.......3
Ancylus 1 Acmella 2 Alycaeus 1
Limnaea 3 Diplommatina 41 Leptopoma . 42 Anodonta . . 1
Planorbis 3 Arinia 6 Lagochilus . I; Cyrena .. 33.38
Physa 2 Pupina . 5 Cyclophorus . 381 Corbicula . . 7
Registoma . 7 Ditropis ri
Islands adjacent to the Philippines.— The Philippines are
connected with Borneo by two distinct ridges or banks of eleva-
tion, which enclose between them the Soo-loo or Mindoro Sea.
There can be little doubt that these ridges represent the ancient
highway of transit, by which Indo-Malay species passed into the
Philippines. The depth of the sea on either side is profound,
ranging from an average of about 1000 fathoms west of Palawan
to 2550 off the south-west coast of Mindanao.
It appears that the fauna of the Soo-loo ridge is definitely
Philippine up to and including Bongao, Sibutu, and Bilatan, the
last islands at the Bornean end of the ridge. On these are found
two species of Cochlostyla and an Obbina.
The Palawan ridge may also be described as more or less
Philippine throughout. One species of Cochlostyla occurs on
Balabae, just north of Borneo, and two on Palawan, but these
are perhaps counterbalanced by the definitely Indo-Malay Amphi-
dromus and Opisthoporus (1 sp. each). At the northern end of
the ridge, on Busuanga and Calamian, the Philippine element
predominates.
Representatives of two remarkable groups of Helix ( Camaena
and Phoenicobius) occur along the Palawan ridge and in Mindoro.
The Phoenicobius find their nearest allies in the curious small
group known as Obdba, from N. Celebes, the Camaena possibly in
a type of Helix (Hadra) occurring in New Guinea and N.E.
Australia. The only other Helix from the whole of the E. Indies
which bears any resemblance to the Phoenicobius group is H.
codonodes Pfr., which is peculiar to the Nicobars. A few forms
assigned to Camaena also occur in Further India and Siam. It
would appear possible, therefore, that these two isolated groups
are a sort of survival of a fauna which perhaps had once a much
more extended range.
316 CHINA CHAP.
(2) The Chinese Sub-region. — The Chinese Sub-region in-
cludes the whole of China from its southern frontier up to and
including the basin of the Blue or Yang-tse River, together with
the coast district, including Corea, perhaps as far north as Vladi-
vostok, and the outlying islands of Hainan, Formosa, the Loo-
Choo and Bonin groups, and Japan to the north of Niphon. It
may be divided into two provinces, the Chinese and the Japanese.
(a) The fauna of the Chinese province proper bears, in many
respects, strong marks of relationship to that of India and Siam.
Thus Streptaxis, Helicarion, Macrochlamys, Kaliella, Sitala, Ario-
phanta, Rhysota, Hemiplecta, Diplommatina, Opisthoporus, Ptero-
cyclus, Lagochilus, and Alycaeus all occur, especially in Southern
China. The two points in which the sub-region bears special
marks of individuality are Helix and Clausilia. The sub-genera
of Helix which have their metropolis in China are Satswma,
Cathaica, Aegista, Acusta, Huhadra, Plectotropis, and Plectopylis.
Sinistral forms (compare Fig. 213) are rather prevalent. In
several cases —e.g. T'richia Gonostoma Fruticicola—there is a
reappearance of forms which appear to belong to well-known
European sub-genera. Clausilia here attains a kind of second
centre of distribution, and is represented by its finest forms,
which belong to several peculiar
sub-genera. The carnivorous Mol-
lusea are not abundant, and are rep-
resented by Rathovisia (a peculiar
genus of naked slug), Hnnea, and
Streptaxis. In the western provinces
— Buliminus is abundant in several
Fig. 213. — Helix (Camaena) cica- sub-genera, one of which appears to
HSCS NUT GLEE be the European Napaeus.
There is little which is striking in the operculates, which are
most abundant in the south, and appear to be mainly derived
from Indian and Siamese sources. The occurrence of Helicina
(3 sp.), Omphalotropis (1), Leptopoma (2), and Realia (2), is
evidence of some influence from the far East. Heudeia is a
very remarkable and quite peculiar form of Helicina with
internal plicae, perhaps akin to the Central American Ceres.
Fresh-water genera are exceedingly abundant, especially
Melania, Unio, and Anodonta. The occurrence of Mycetopus
(a South-American genus) is remarkable. There are several
x CHINA, HAINAN, FORMOSA, AND COREA zi
peculiar forms of fresh-water operculates, whose exact position is
hardly yet assured.
Land and Fresh-water Mollusca of the Chinese Province
Rathouisia . 1 Trichia. . .10 Succinea 8 Leptopoma. , 2
Streptaxis . . 7 Cathaica . . 22 Vaginula 7 Lagochilus. . 10
Ennea . 12 Aegista. . .10 Limnaea 2 Cyclophorus 18
Parmarion . 2 Armandia . 3 Planorbis 6 Coelopoma . i!
Helicarion . 15 Acusta 15 Melania. . . 44 Pterocyclus 3
Euplecta 3 Obbina . 1 Paludomus 3 Opisthoporus . 4
Macrochlamys 19 Camaena 5 Bithynia . . 12 Cyclotus . . 10
Microcystina . 2 Euhadra . 14 Lithoglyphus . 3 Scabrina 4
Microcystis 7 Plectopylis. 19 Melantho(?) . 1 Ptychopoma . 12
Kaliella . . 16 Stegodera . 6 Pachydrobia 1 Omphalotropis 1
Sitala 8 Chloritis 1 Prososthenia . 2 Realia 2
Ariophanta 1 Hel. Inc. sed. . 39 Stenothyra. 2 Pseudopomatias 1
Rhysota. 5 Buliminus . 21 Hydrobia 2 Helicina. 3
Hemiplecta 1 Buliminopsis . 8 Mecongia 1 Georissa. +
Trochomorpha 2 Buliminidius 3 Oncomelania . 9 MHeudeia. 1
Limax 1 Napaeus 14 Margaracya 1 Cyclas 1
Philomycus 1 Rachis (?) . 4 Rivularia 4 Corbicula 50
Patula 2 Pupa 10 Delavaya Lone: . . OO
Gonostoma. 4 Clausilia . 102 Fenouillia . 1 Monocondylaea 1
Metodontia 2 Opeas .. .12 Vivipara 34 Anodonta 5d
Vallonia 1 Euspiraxis. . 1 Diplommatina 20 Mycetopus. 12
Plectotropis . 9 Subulina 5 Pupina . 6 Pseudodon . 1
Fruticicola 11 Stenogyra(?). 12 Alycaeus 23 Dipsas 4
Satsuma . 14
The island of Hainan, in the extreme south of the sub-
region, has 40 species of Mollusca, 22 of which are peculiar, but
there is no peculiar genus.
The Mollusea of Formosa, although in many cases specifically
distinct, show close generic relationship with those of China.
The characteristic Chinese groups of Helix and Clausilia occur,
and there is still a considerable Indian element in several species
of Streptaxis, Macrochlamys, Kaliella, and Alycaeus. The oc-
currence of two Amphidromus, a genus which, though Siamese,
is not found in China or Hainan, is remarkable.
The peninsula of Corea must undoubtedly be included in the
Chinese sub-region. It is true that the land operculates scarcely
occur, but there are still a number of Clawsilia, and several of
the characteristic Chinese groups of Helix are reproduced. In
some points Corea appears to show more affinity to Japan than
318 JAPAN AND NEW GUINEA CHAP.
to China, four of the Helices being specifically identical with
those of Japan, but the peninsula is at present too little explored
for any generalisations to be made as to its fauna in this respect.
(b) Japanese Province. — Kobelt distinguishes four groups
of Mollusca inhabiting Japan (a) circumpolar species, actually
occurring in Europe, Siberia, or N. America, or represented by
nearly allied species (these of course do not belong to the
Japanese province as such); (6) Indo-tropical species; (¢) species
which are Chinese or akin to Chinese; (d) peculiar species, a
mixture of two forms, southern and northern, the latter being
chiefly Hyalinia, Patula, and Fruticicola. Out of a total of 193
Japanese species, at least 164 are peculiar.
The Japanese Helices belong to sub-genera common to
China (Plectotropis 8, Huhadra 21, Acusta 23?); but the
Naninidae scarcely occur at all. The principal feature of the
fauna is the development of Clausilia, which presents some
extraordinarily fine forms. One slug (Philomycus) is identical
with an Indian species. The operculates, which consist mainly
of a few species each of Diplommatina, Cyclophorus, Pupinelia,
Pupina, Helicina, and Georissa, belong almost exclusively to
the southern islands Kiu-siu, Sikoku, and southern Niphon. The
three species usually reckoned as Japonia are probably forms of
Lagochilus.
C. The Australasian Region
This region includes all the islands of the Pacific east of
the Moluccas, and falls into three sub-regions —the Papuan,
the Australian, and the Polynesian.
1. The Papuan Sub-region may be divided into— (a) the
Papuan Province proper, which includes New Guinea, with the
Aru Is. and Waigiou, the Admiralty Is., New Ireland, New
Britain, and the d’Entrecasteaux and Louisiade Groups; (6)
the Queensland Province, or the strip of N.E. Australia from
C. York to the Clarence R. (about 29° S. lat.); (e¢) the
Melanesian Province, which includes the New Hebrides, New
Caledonia, with the Loyalty Is. and the Viti Is. The Solomons
form a transition district between the Papuan and Melanesian
provinces, abounding on the one hand in characteristic Papuan
Helices, while on the other they form the north-western limit of
NEW GUINEA 319
Placostylus, the group especially characteristic of the Melanesian
province.
(a) The Papuan Province.—The molluscan fauna of New
Guinea is the richest and by far the most original of all the
Australasian region. We find ourselves, almost in a moment, in
a district full of new and peculiar forms. New Guinea may be
regarded as the metropolis of the rich Helicidan fauna, which is
also characteristic of the Moluccas to the west, of N. and N.E.
Australiato the southand south-east, and of the Solomons and other
groups to the north-east. Here abound species of Papuina and
Insularia (the latter being quite peculiar), among which are
found, if not the largest, certainly the most finished forms of all
existing Helices. Chloritis (13 sp.), Planispira (5), and Cristi-
gibba (9) are common with the Moluccas, while a tropical
Australian element is shown in Pedinogyra (1) and Hadra (4).
Very remarkable, too, is the occurrence of one species of Obbina
and Rhysota, genera which culminate in the Philippines and here
find their most eastward extension; while a single Corasia serves
to form a link between the Corasia of the Philippines and those
of the Solomon Is., if the latter are true Corasia.
We naturally find considerable traces of a Polynesian element,
which appears to be principally characteristic of the eastern part
of the island. Most noteworthy in this respect is the occur-
rence of Partula (3), Tornatellina (1), Charopa (1), Thalassia
(3). As compared with the true Pulmonata, the operculates are
feebly represented, and the great majority are of a markedly
Polynesian type. Nota single Cyclophorus occurs; Lagochilus,
Alycaeus, and all the tubed operculates, so marked a feature of
the Indo-Malay fauna, are conspicuous by their absence, and the
prevailing genera are Cyclotus, Helicina, and a number of sections
of Pupina. Leptopoma, as in the Philippines, is strongly repre-
sented. Not that an Indo-Malay element is altogether absent.
We still have Xesta (5), Hemiplecta (8), and even Sitala (2),
but the great predominance of Helix seems to have barred the
progress, for the greater part, of the Indian Naninidae.
The slugs appear to be represented by a solitary Vaginula.
A single Perrieria is a very marked feature of union with
Queensland, where the only other existing species (P. australis)
occurs. The solitary Rhytida, so far the only representative of
the carnivorous group of snails, emphasises this union still
320 NEW GUINEA AND ARU ISLANDS CHAP.
further. Little is known of the fresh-water fauna. Melania
(28 sp.) is predominant, but on the whole the relations are
Australian rather than Indo-Malay. Ampullaria is wanting,
while a decisive point of similarity is the occurrence of Lsidora
(3 sp.), a genus entirely strange to the Oriental region, but
markedly characteristic of the Australasian.
Land and Fresh-water Mollusca of New Guinea
Rhytida 1 Thalassia. . 3 Calycia 4 Diplommatina 1
Helicarion 2 Ochthephila(?) 1 Partula 3 Pupina;:— os
oni expe: :
3
—
Ww: 2 :
Ome. Bw. Crw.
GREATER ANTILLES
S
g z
3 3)
5 A
5 a
ee
os 2
pC?) 1
iu ae
1
13
—
for)
2 moos OCObO® or:
(oof dl — tee ee
14
es
se 7
ae 2
i 3
=, 6
me
34
- 1
S 6
eras
~ 1
“2 «414
14-9
36-385
es 1
7 (2)
: oo Porto Rico.
a] So) — ee
> =D bh:
. mM O92 Coe to: 3
COia el ec
ee hf — rs ee
Opeas
Subulima .
Glandinella
Spiraxis
Melaniella .
Geostilbia .
Cionella
Leptinaria .
Obeliscus .
Pupa.
Vertigo
Strophia
Clausilia
Succinea
Vaginula
Megalomastoma
Neocyclotus
Licina
Jamaicia
Crocidopoma
Rolleia
Choanopoma
Ctenopoma
Cistula
Chondropoma
Tudora
Adamsiella
Blaesospira
Xenopoma
Cistula
Colobostylus
Diplopoma
Geomelania
Chittya
Blandiella .
Stoastoma .
Eutrochatella
Lucidella
| Aleadia
| Helicina
Proserpina.
> pO =1b0 ooo Cuba.
> jm > Jamaica.
to: bo §. Domingo.
Ch aS
7 4
7,
é °
ci enka
mboor:s cos COR:
—
bo
: = 5 :
© OOWH Orit. -
ee)
STMOTUOS) 6 os
os 1
80 1
6 6
4 1
14 4
16 924
4 :
351
bobo co! 2 0: et noo Porto Rico.
- Wr WR bw:
The Virgin Is., with St. Croix, Anguilla, and the St. Bar-
tholomew group (all of which are non-voleanic islands), are
related to Porto Rico, while Gaudeloupe and all the islands to the
south, up to Grenada (all of which are voleanic), show marked
traces of S. American influence.
St. Kitt’s, Antigua, and
Montserrat may be regarded as intermediate between the two
groups.
St. Thomas, St. John, and Tortola have each one
352 LESSER ANTILLES CHAP.
Plagioptycha and one Thelidomus, while St. Croix has two sub-
fossil Caracolus which are now living in Porto Rico, together with
one Plagioptycha and one Thelidomus (sub-fossil). The gradual
disappearance of some of the characteristic greater Antillean
forms, and the appearance of 8. American forms in the Lesser
Antilles, is shown by the following table: —
; Thomas.
. Croix.
Anguilla,
St. Kitt’s.
Antigua.
Guadeloupe.
Dominica.
Martinique.
St. Lucia.
Barbados.
St. Vincent.
Trinidad.
Bulimulus
Cylindrella
Macroceramus é
Cyclostomatidae, etc. .
Dentellaria
Cyclophorus .
Amphibulimus
Homalonyx
S
o°
_
=
=
=
=
| m PR
1
3
3
re ona | Tortola.
woe
23
hoe OR: RO
Aooboot: 5:
(d) In Guadeloupe we find Cyclophorus, Amphibulimus,
Homalonyx, and Pellicula, which are characteristic of S. America,
and nearly all recur in Dominica and Martinique. These islands
are the metropolis of Dentellaria, a group of Helix, evidently
related to some of the forms developed in the Greater Antilles.
Stragglers occur as far north as St. Kitt’s and Antigua, and there
are several on the mainland as far south as Cayenne. ‘Traces of
the great Bulimus, so characteristic of South America, occur as
far north as S$. Lucia, where also is found a Parthena (San
Domingo and Porto Rico). Trinidad is markedly 8. American ;
59 species in all are known, of which 22 are peculiar, 28 are
common to S. America (8 of these reach no farther north along
the islands), and only 5 are common to the Antilles, but not to
S. America. The occurrence of Gundlachia in Trinidad has
already been mentioned.
The Bermudas show no very marked relationship either to
the N. American or to the West Indian fauna. In common
with the former they possess a Polygyra, with the latter (intro-
duced species being excluded) one species each of Hyalosagda,
Subulina, Vaginula, and Helicina, so that, on the whole, they
may be called West Indian. The only peculiar group is Poecilo-
zonites, a rather large and depressed shell of the Hyalinia type.
(2) The Central American Sub-region may be regarded as
xI CENTRAL AMERICA 353
extending from the political boundary of Mexico in the north
to the isthmus of Panama in the south. It thus impinges on
three important districts—the N. American, West Indian, and 8.
American; and it appears, as we should perhaps expect, that the
two latter of these regions have considerably more influence
upon its fauna than the former. Of the N. American Helicidae,
Polygyra is abundant in Mexico only, and two species of Strobila
reach N. Guatemala, while the Californian Arionta occurs in
Mexico. S. American Helicidae, in the sub-genera Solaropsis
and Labyrinthus, occur no farther north than Costa Rica. Not
a single representative of any of the characteristic West Indian
Helicidae occurs. Bulimulus and Otostomus, which form so large
a proportion of the Mollusca of Venezuela, Colombia, Ecuador, and
Peru, together with Orthalicus, are abundant all over the region.
Again, Cylindrella, Macroceramus, and some of the characteristic
Antillean operculates, are represented, their occurrence being in
most cases limited to the eastern coast-line and eastern slope of
the central range.
Besides these external elements, the region is rich in indigenous
genera. Central America is remarkable
for an immense number of large carni-
vorous Mollusca possessing shells. There
are 49 species of Glandina, the bulk of
which occur in eastern and southern
Mexico; 36 of Streptostyla (S.E. Mexico
and Guatemala, only 1 species reaching
Venezuela and another Peru); 5 of Sala-
siella, 2 of Petenia, and 1 of Strebelia; the
last three genera being peculiar. Strept-
axis, fairly common in S. America, does
not occur. Velifera and Cryptostracon,
two remarkable slug-like forms, each with
a single species, are peculiar to Costa Rica.
Among the especial peculiarities of the
Fic. 232.—Examples of
region are the giant forms belonging to the _ characteristic Mexican
< 2 : ele = . Mollusea: A, Coelocen-
Cylindrellidae, which are known as Holo- RN. Fl ree eae
spira, Eucalodium, and Coelocentrum (Fig. — Streptostyla Delattrei
232). They are almost entirely peculiar “ine
to Mexico, only 7 out of a total of 33 reaching south of that
district, and only 1 not occurring in it at all. :
VOL. Ill 2A
354 CENTRAL AMERICA CHAP.
The land operculates are butscanty. Tomocyclus and Amphi-
cyclotus are peculiar, and Schasicheila, a form of Helicina, occurs
elsewhere only in the Bahamas. Ceres (see Fig. 18, C, p. 21) and
Proserpinella, two remarkable forms of non-operculate Helicinidae
(compare the Chinese Heudeza), are quite pecuhar. Pachychilus,
one of the characteristic fresh-water genera, belongs to the S.
American (Melaniidae) type, not to the N. American (Pleuro-
ceridae). Among the fresh-water Pulmonata, the Aplecta are
remarkable for their great size and beauty. In the accompany-
ing table “* Mexico” is to be taken as including the region from
the United States border up to and including the isthmus of
Tehuantepec, and “ Central America” as the whole region south
of that point. .
Land Mollusca of Central America
2 s & 2
= a
He aes eS Wo Sees
2 OEE eo 2 SES co}
= Odds O08 = O45 O28
Strebelia 1 ae ...| Berendtia . i| aS
Glandina 33 18 3 | Orthalicus 6 3 3
Salasiella 4 sts 1) Pupa 1 1 1
Streptostyla. 18 12 6 | Vertigo 1 dss sae
Petenia os 1 1 | Holospira 12 rae es
Limax : Bhd ase 1 ... | Coelocentrum 6 1 1
Velifera ‘ sie Nicies 1 ... | Eucalodium . 15 are 5
Omphalina Biel Lt) 1 1| Cylindrella . 6 qd re
Hyalinia 2 5 3 | Macroceramus 2 1 te
Guppya : Sas 8 3 | Simpulopsis . 2 1 ly.
Pseudohyalina 2 2 | Caecilianella 1 BE =
Tebennophorus . 1 es =. | Opeds.. 1 2 =
Cryptestracon ;. .. 1 ... | Spiraxis 8 2 1
Xanthonyx . 4 sits Leptinaria sins 2 es
Patula . : 3 Sui 4 | Subulina 2 3 +
Acanthinula. 1 2 2 | Succinea i 3 1
Vallonia as 1 Vaginula 1 due aes
Trichodiscus 2 2 3 | Aperostoma . sae 4 ik
Praticolella . 1 x 1 | Amphicyclotus 2 1 2
Arionta : 3 .. | Cystopoma 2 wid we
Lysinoe : : 1 1 1| Tomocyclus . 4 1 2
Oxychona 2 5 Choanopoma 2 2 ae
Solaropsis aise 2 ... | Chondropoma 2 11 —
Polygyra . = 1 2 | Helicina 13 10 6
Strobila 1 A ... | Schasicheila. 2 oad 1
Labyrinthus. by 5 a+ |Geres ; 2 a oe
Otostomus . ve e2S 20 7 | Proserpinella 1 ae
Bulimulus 6 5 2
(3) The Colombian Sub-region includes Colombia, New
Grenada, Venezuela, Guiana, Ecuador, Peru, and Bolivia. It has
XI COLOMBIA AND VENEZUELA Rn
been usual to separate off the two latter countries as forming a dis-
tinct “ Peruvian” sub-region ; but there is, as will be seen, abso-
lutely no line to be drawn between the Mollusca of Peru and those
of Ecuador; nor would one, on geographical considerations, expect
to be able to draw such a line. A better method of subdivision,
so far as the species of the whole eastern portion of the region
are concerned, would be to group the Mollusca according to the
altitude at which they occur, were it not that the evidence on
this point is at present but fragmentary. We know, however,
that all along the line of the Andes certain species, more parti-
cularly of Bulimulus, occupy their own zones of elevation, some
ascending as high as 10,000 feet above the sea, and never occur-
ring on the plains.
In the northern portions of this sub-region, Central American
and West Indian influence is felt toa certain extent. Thus there
Fie. 233. — A, Orthalicus
Deburghiae Reeve,
Ecuador; B, Bulimus
(Pachyotus) egregius
Jay, Brazil.
are eight Glandina and one Streptostyla in Venezuela and Colom-
bia together with one or two species of Cistula, Chondropoma,
Proserpina, and Cylindrella, while a single Strophia (decidedly
a straggler) occurs at Curacao. In Demerara and Cayenne there
are three or four species of Dentellaria. In Ecuador, however,
Glandina diminishes to three species, and in Peru disappears
altogether, although one Streptostyla occurs. Similarly the
West Indian operculates are reduced to one Chondropoma
(Ecuador) and disappear entirely in Peru.
385 ECUADOR, PERU, AND BOLIVIA CHAP,
The Helicidae are most abundant in the north and west, and
are represented by several very striking sub-genera, some of which
possess retnarkably toothed apertures, and perhaps betray an
ancestry common to some of the West Indian genera. Of these,
Labyrinthus has 12 species in Venezuela and Colombia, 5 in
Ecuador, and 8 in Peru and Bolivia; Jsomeria 12 in Venezuela
and Colombia, 20 in Ecuador, and 2 in Peru and Bolivia;
Salaropsis is represented in these countries by 6, 3, and 7 species,
and Systrophia by 4,5, and 8 species respectively.
Clausilia —in the group Menta — appears in some numbers
along the Andes chain, the only other representative in the New
World being the solitary species occurring at Porto Rico. There
have been described, from Venezuela and Colombia 10 species,
from Ecuador 5, and from Peru and Bolivia 12.
Another marked feature of the region is the occurrence
of the Orthalicidae, in the two genera Orthalicus and Porphy-
robaphe. The latter of these magnificent forms is peculiar,
while the former reaches Mexico, the West Indies, and Brazil.
Ecuador, which contains 23 species, seems the metropolis of
the group.
Bulimus and Bulimulus, the former genus being peculiar to
S. America and the adjacent islands, are largely
represented, the former in the three groups
Borus, Dryptus, and Orphnus. These attain
their maximum in Peru, with 25 species, but
Venezuela and Colombia have as many as 17.
Bulimulus has been subdivided into a number
of groups, e.g. Drymaeus, Mesembrinus, Thau-
mastus, Mormus, Scutalus, with many others,
—the exact scientific limits of which are not
easily discernible. It must suffice here to
state that Peru seems to be the head-quarters
of the group with about 190 species (which
probably may well be reduced ), Ecuador having
about 70, and Venezuela and Colombia between
80 and 90.
Fic. 234. — Rhodea Two very remarkable forms belonging to the
gamed aos» Pupidae, Anostoma (Fig. 154, p. 248) and Toii-
gerus, occur in Venezuela, the metropolis. ho-
dea, another very peculiar shell (Fig. 284), whose exact family
XI THE GALAPAGOS — BRAZIL 357
position is uncertain, is pecuhar to New Grenada. The land
operculates are few in number, and in Bolivia almost disappear.
They belong principally to Neocyeclotus (of which 11 species
occur in Venezuela and Colombia) and Helicina (10 species in
the same district), besides the stragglers already mentioned from
West Indian sources, and a few Cydopiorn: Bourcieria is a
form of Helicina peculiar to Ecuador. Ampullaria, with Cera-
todes, a pecuhar planorbiform sub-genus, and Hemisinus, form
the bulk of the fresh-water operculates.
Lhe Galapagos. — Thirty-four species of land Mollusca, all
pecuhar, are known from these islands; 25 of these are forms
of Bulimulus. There are no Helicidae, one each of Hyalinia,
Leptinaria, and Helicina, and two Pupa. The Bulimulus are
mostly of the group Jesiotis, and in their brown colour bear
some outward resemblance to the dark Achatinella of the Sand-
wich Is., living as they do mostly under scoriae on the ground,
and not on trees. In type, however, they appear to be derived
from Chili and Peru, rather than from the parts of S. America
immediately contiguous. Another section (Pleuropyrgus 2 sp.)
closely resembles a marine Chemnitzia. The islands are all
volcanic, and are probably not the resuit of subsidence; thus the
existing species are not to be regarded as the relics of a more
widespread fauna, but as a new set of inhabitants.
(4) The Brazilian Sub-region.— This immense district is
very little known, except in the south, and it is consequently
impossible to give any satisfactory account of its Mollusca. It
is possible that eventually it will be found that it falls into
provinces which correspond more or less to (a) the Amazon
basin; (6) the mountainous district in the east, drained by the
Tocantins and the San Francisco; (¢) the Parana basin in the
south central district; and (d) the Argentine or Pampas district
in the extreme south. But at present the data are insufficient
to establish any such subdivisions, whose existence, if proved,
would have an important bearing on the problem of the coales-
cence of S. America into its present form.!
The Agnatha are represented by Streptazis alone (17 sp.).
Helix is rare, but includes the peculiar Polygyratia (Fig. 150 A,
p- 246), while Labyrinthus (2 sp.), Solaropsis (5 sp.), and Systro-
1 Compare von Martens, Malak. Blatt. 1868, Ds 169; von Ihering, Nachr.
Deutsch. Malak. Gesell. 1891, p. 98. :
35 8 ARGENTINA — CHILI CHAP.
phia are common with the Colombian Sub-region, and Oxychona
(4 sp.) with the Central American. Bulimus
has in all 36 species, the sub-genera Pachyo-
tus (Fig. 233) and Strophochilus being pecul-
iar. Bulimulus, though not so abundant as
in Peru and Ecuador, has about 60 species, of
Fic. 235. — Bulimulus which Navicula (Fig. 235) is the most remark-
ce ee able group. Megaspira is peculiar. Orthali-
cus has only 4 species, while Tomigerus (4 sp.)
and Anostoma (3 sp.) are common with Venezuela. Land opercu-
lates are scarce, and appear to include only Neocyclotus, Cyclo-
phorus, and Helicina.
In Argentina, which may probably rank as a separate pro-
vince, the tropical forms greatly decrease,
Streptaxis being reduced to 2 species, and
Bulimus and Bulimulus together to 40, while
Orthalicus, the great Helices, and the land
operculates disappear altogether. Odonto-
stomus (Fig. 236), a genus of the Pupidae, is
abundant in the northern part of the province.
Two or three species of Chilina occur. :
(5) The Chilian Sub-region.—The greater 5. 036 _ odonto-
part of Chili, from its arid and rainless climate, stomus pantagru-
is unfavourable to the existence of land Mol- ees reat zs
lusca. Bulimus (Borus) still has 3 or 4 species,
and Bulimulus (Plectostylus 11, Scutalus 9, Peronaeus 7) is
fairly abundant, but the profusion of the tropics is wanting.
There are no carnivorous genera, and only two land operculates.
A remarkable form of Helix (Macrocyelis, Fig. 237) is quite
peculiar, but the majority of the species belong to two rather
obscure groups, Stepsanoda and Amphidoxra. Chilina, a singu-
larly solid form of Limnaea (of which 8 sp., with a sub-genus
Pseudochilina, occur in Chili), is peculiar to Chili, S$. Brazil,
and Patagonia. From the two islands of Juan Fernandez and
Masafuera, are known several Helix, of Chilian affinity, several
curious Succinea, a Homalonyx, Leptinaria, and Nothus, and three
species of Tornatellina, with the almost universal Limax gagates.
The question of the existence at some remote period of a
Neantarctic continent, which formed a communication between
the three great southern peninsulas of the world, is one on
XI QUESTION OF A NEANTARCTIC CONTINENT 359
which the Mollusca may offerevidence. Von Ihering holds that
an essential difference can be observed between certain of the
Unionidae which inhabit 8. America, Africa, and Australia with
New Zealand, and those which inhabit Europe, Asia, and N.
America, but the point can hardly be regarded as definitely
established at present. Something perhaps may be made of the
distribution of Bulimus and Bulimulus. It seems difficult to
explain the occurrence of sub-fossil Bulimus on St. Helena except
on some such lines as have been recently adduced to account for
the presence of struthious birds in the Mascarenes, and possibly
the form Livinhacea may be a trace of the same element in S.
Africa. Again, the Liparus of S. and W. Australia, with the
Caryodes of Tasmania, and the Leucotaenta and Clavator of Mada-
gascar (which all may be related to Bulimus), together with the
Placostylus of New Caledonia and the adjacent islands, reaching
Fic. 237. — Macrocyclis
laxata Fér., Chili.
even to New Zealand, and perhaps even the Amphidromus of
Malaysia (which are more akin to Bulimulus), may be thought
to exhibit, in some remote degree, traces of a common ancestry.
The land operculates give no help, and, of the carnivorous
genera, 2thytida is a marked link between Africa and Austraha,
while Streptaxis is equally so between S. America and Africa.
As regards fresh-water Gasteropoda, Ampullaria is common to S.
America and Africa, while Js¢dora is common to Africa, Australia,
and New Zealand, but is altogether absent from S. America.
Gundlachia occurs in Florida, Trinidad, and Tasmania, but has
not been detected in Africa. It must be concluded, therefore,
that the present state of the evidence which the Mollusca can
afford, while exhibiting certain curious points of relationship
between the three regions in question, is insufficient to warrant
any decided conclusion.
CHAPTER XII
DISTRIBUTION OF MARINE MOLLUSCA — DEEP-SEA MOLLUSCA
AND THEIR CHARACTERISTICS
MARINE Mollusca may be divided roughly into Pelagic and
non-Pelagic genera. To the former division belong all Ptero-
poda and Heteropoda, and a large number of Cephalopoda,
together with a very few specialised forms of Gasteropoda
(Clanthina, Litiopa, Phyllirrhoe, etc.). Pelagic Mollusca appear,
as a rule, to live at varying depths below the surface during the
day, and to rise to the top only at night. The majority inhabit
warm or tropical seas, though some are exceedingly abundant
in the Arctic regions; Clione and Limacina have been noticed as
far north as 72°.1
The vertical range of Pelagic Mollusca has received attention
from Dr. Murray of the Challenger, Professor Agassiz of the
Blake and Albatross, and others. Agassiz appears to have estab-
lished the fact that the surface fauna of the sea is hmited to a
comparatively narrow belt of depth, and that there is no inter-
mediate belt of animal life between creatures which live on or
near the bottom and the surface fauna. Pelagic forms sink to
avoid disturbances of various kinds, to depths not much exceed-
ing 150 to 200 fathoms, except in closed seas like the Gulf of
California and the Mediterranean, where the bathymetrical range
appears to be much greater.”
Non-Pelagic Mollusca are, from one point of view, con-
veniently classified according to the different zones of depth at
1 The distribution of some Pteropoda has been worked out by Munthe, Bih.
Svensk. Ak. Handl. XII. iv. 2, by Pelseneer ‘‘ Challenger’ Rep., Zool. xxiii., and
by Boas, Spolia Atlantica.
2 Bull. Mus. C. Z. Harv. xiv. p. 202; xxiii. p. 34 £.
360
CHAP. XII PHENOMENA OF DISTRIBUTION 361
which they occur. Thus we are enabled to distinguish Mollusca
of (a) the littoral, (6) the laminarian, (¢) the nullipore, or
coralline, and (d) the abyssal zones. It must be borne in mind,
however, that these zones cannot be exactly defined, and that
while the littoral zone may be understood to imply the area
between tide-marks, and the abyssal zone a depth of 500
fathoms and upwards, the limits between the laminarian and
the coralline, and between the coralline and abyssal zones can
only be fixed approximately.
The difficulty of assigning special genera or species to special
‘zones of depth’ is increased by two important facts in the
phenomena of distribution. In the first place, it is found that
species which occur in shallow water in northern seas often
extend to very deep water in much lower latitudes. This in-
teresting fact, which shows the importance of temperature in
determining distribution, was first established by the dredgings
of the Lightning and Porcupine off the western coasts of Europe.
In the second place, a certain number of species seem equally at
home in shallow and in abyssal waters, in cases where a great
difference of latitude does not occur to equalise the temperature.
Thus the Challenger found Venus mesodesma living on the beach
(New Zealand) and at 1000 fath. (Tristan da Cunha); Lima
multicostata in ‘shallow water’ (Tonga and Port Jackson) and
at 1075 fath. (Bermuda); Scalaria acus from 49 to 1254 fath.
CN. Atlantic); and S. hellenica from 40 to 1260 fath. (Canaries).
The Lightning and Porcupine found, or record as found,! Anomia
ephippium at 0 to 1450 fath., Pecten groenlandicus at 5 to 1785
fath., Lima subauriculata at 10 to 1785 fath., Modiolaria discors
at 0 to 1785 fath., Crenella decussata at 0 to 1750 fath.,
Dacrydium vitreum at 80 to 2750 fath., Arca glacialis at 25
to 1620 fath., Astarte compressa at 3 to 2000 fath., and Sero-
bicularia longicallus at 20 to 2435 fath. Puncturella noachina
has been found at 20 to 1095 fath., Natica groenlandica at 2 to
1290 fath., Rissoa tenuisculpta at 25 to 1095 fath. In many
of these cases we are assured that no appreciable difference can
be detected between specimens from the two extremes of
depth.
In spite, however, of these remarkable vagaries on the part
of certain species, we are enabled roughly to distinguish a large
1 See papers in P. Z. §. 1878-85.
362 RECENT EXPLORING EXPEDITIONS CHAP.
number of genera as ‘shallow-water’ and ‘ deep-water’ respec-
tively, while a still larger number occupy an intermediate
position. Among shallow-water genera may be named Patella,
LIittorina, Nassa, Purpura, Strombus, Haliotis, Mytilus, Cardium,
Solen; while among deep-water genera are Pleurotoma, Scissu-
rella, Seguenzia, Dentalium, Cadulus, Limopsis, Nucula, Leda,
Lima, and Axinus.
Theories on the geographical distribution of marine Mollusca
have been revolutionised by the discoveries of recent exploring
expeditions. The principal have been those of Torell (Swedish)
(1859-61) on the coasts of Greenland and Spitzbergen ; of the
Lightning and Porcupine (British) in 1868-70, in the N.E.
Atlantic, off the Scotch, Irish, French, and Portuguese coasts,
and in the Mediterranean ; of the Challenger (British), under
Sir C. Wyville Thomson, in 1878-76, in which all the great
ocean basins were dredged or sounded; of the Blake (American),
under Alexander Agassiz, in 1877-80, in the West Atlantic,
Gulf of Mexico, and Caribbean Seas; of the 7’ravailleur (French)
in 1880-88, off the west coasts of France, Portugal, and Morocco,
Madeira, the Canaries, and the Golfe du Lion; of the Talisman
(French) in 1882, off the west coast of Africa from Tangier to
Senegal, the Atlantic Islands, and the Sargasso Sea; of the
Albatross (American) in 1891, off the west coast of tropical
America; of several other vessels belonging to the U.S. Fish
Commission and Coast Survey, off east American shores; and
of the Prince of Monaco in the Hirondeile and Princesse
Alice at the present time, in the N. Atlantic and Medi-
terranean.
The general result of these explorations has been to show
that the marine fauna of very deep water is much the same all
the world over, and that identical species occur at points as far
removed as possible from one another. The ocean floor, in fact,
with its uniform similarity of temperature, food, station, and
general conditions of life, contains no effectual barrier to the
almost indefinite spread of species! To give a few instances.
The Challenger dredged Stlenia Sarsti in 1950 fath., 1100
1 A break in this uniformity may be found underneath the course of a great
oceanic current like the Gulf Stream, which rains upon the bottom a large amount
of food. A. Agassiz (Bull. Mus. C. Z. Harv. xxi. p.185 f.) explains in this way
the richness of the fauna of the Gulf of Mexico as compared with that of the
west coast of tropical America.
x WIDE DISTRIBUTION OF DEEP-WATER FORMS 363
miles south-west of Australia, and also in 2650 fath. off the mouth
of the Rio de la Plata; Semele profundorwm in 1125 fath. near
the Canaries, and in 2900 fath. mid N. Pacific; Verticordia
deshayesiana in 155 fath. near Cape York, and in 350 fath. off
Pernambuco; Arca pteroessa in 2050 fath. mid N. Pacific, in
1000-1675 fath. west of the Azores, and in 890 fath. off the
West Indies; Arca corpulenta in 1400 fath. off N.E. Australia,
in 2425 fath. mid-Pacific, and in 1875 fath. near Juan Fer-
nandez; Lima goliath in 775 fath. off S. Japan, and in 245
fath. off S. Patagonia; Pleurotoma engonia in 700 fath. north-
east of New Zealand, and in 345 fath. off Inoshima. A surpris-
ing range was occasionally found even in shallow-water species;
thus Petricola lapicida was discovered by the same expedition
in the West Indies and N. Australia, Cardita calyculata off
Teneriffe and in Bass Strait, Arca imbricata off Cape York
and in the West Indies, Modiolaria cuneata at Port Jackson
and Cape of Good Hope, Lima squamosa at Teneriffe and the
Philippines. In these latter cases it is not improbable that the
species lives in deep water as well, from which it has not yet
been dredged.
It follows from these considerations that any attempt to
classify marine Mollusca under Regions and Provinces can only
apply to Mollusca which occur at moderate depths. The most
important factor in the environment, as determining distribu-
tion, is the temperature of the water, which is probably to be
regarded as affecting not so much the adult Mollusca as their
ova; for the adult might possibly support hfe under conditions
in which the ova would perish. It appears that a sudden change
of temperature is the most effective barrier to distribution,! and
may bring the range of a species to an almost instantaneous
stop, while a very gradual change will allow it to extend its
range very widely.
1 On the western coasts of Europe and America, where the change in surface
temperature is very gradual, Purpura lapillus (the west American ‘species’ are
at best only derivatives) is able to creep as far south as lat. 52° (Mogador) in the
former case, and lat. 24° (Margarita Bay) in the latter, the mean annual tem-
perature of the surface water being 66° off Mogador, with an extreme range of
only 8°, and that of Margarita Bay 73°, with an extreme range of only 5°. On
the eastern coasts, where the Pacific and Atlantic gulf-streams cause a sudden
change of temperature, the Purpura is barred back at points many degrees
farther north, viz. at lat. 41° (Hakodadi), surface temperature 52°, extreme
range 25°; and at lat. 422° (Newhaven), surface temperature 52°, extreme range 30°.
364 ATLANTIC REGION CHAP.
It has been usual to classify marine Mollusca from moderate
depths under the following regions and sub-regions : —
Regions Sub-regions Regions Sub-regions
1. Arctic. . (1. Australian.
3
2. Boreal. C. Australian | 2. Neozealanian.
A. Atlantic and | 3. Celtic. (1. Aleutian.
Circumpolar | 4. Lusitanian. | 2. Californian.
5. West African. | 3. Panamic.
6. South African. TAGHETICAT | 4. RMS
B. Indo-Pacifi 1. Indo-Pacific. | 5. Magellanic.
Fiver | 2. Japanese. . Argentinian.
15
| 6
| 7. Caribbean.
(8. Transatlantic.
A. The Atlantic Region
includes the whole to the eastern shores of the Atlantic, from
the extreme north of the Cape of Good Hope, together with the
circumpolar seas, which may be regarded as roughly bounded by
the Aleutian Islands and the coast of Newfoundland.
(1) The Arctic Sub-region includes the circumpolar seas,
and is bounded in the N. Pacific by a line drawn between Cape
Avinoft in Alaska, and Cape Lopatka in Kamschatka, so as to
exclude the Aleutian Islands. On the western shores of the
Atlantic the cold Labrador current brings it as far south as the
coast of Newfoundland, but on the eastern shores the influence
of the Gulf Stream has the contrary effect, so that the North
Cape may be taken as its southern limit.
The principal genera (many species of which are common to
the whole sub-region) are Volutomitra, Buccinum, Buccinopsis,
Neptunea, Trophon, Bela, Admete, Velutina, Trichotropis, Lacuna,
Margarita, Philine, Pecten, Leda, Yoldia, Astarte, and Mya.
The shells are generally unicoloured, and of a dead white or
rather sombre tint.
(2) The Boreal Sub-region may be subdivided into two pro-
vinces, the European and the American. The former includes
the entire coast-line of Norway, the Faroe Islands, and Iceland
(except perhaps the northern coast), and possibly the Shetland
Islands ; the latter the American coasts from the Gulf of St.
Lawrence to Cape Cod (lat. 42°). Thus the Boreal American
province does not extend nearly so far south as the Boreal
XII BOREAL AND CELTIC SUB-REGIONS 365
European, the reason being that on the American coasts the cold
Labrador current, which hugs the land, bars back the advance of
southern genera, but allows Boreal genera to spread southwards,
while on the European side the warmer conditions produced by
the Gulf Stream keep the Boreal species back, and allow more
southern forms to spread northwards.
Many of the Boreal species occur on both sides of the Atlantic,
and thus support the theory of a more continuous fringe of con-
tinental land once existing along the north of the Atlantic.
Among the prominent genera, besides several of those mentioned
under the Arctic Sub-region, are Purpura, Chenopus, Littorina,
Gibbula, Natica, Patella, Tectura, Chiton, Doris, Aeolis, Tellina,
Thracia.
(8) The Celtie Sub-region includes the British Islands (except-
ing perhaps the Shetland Islands), the coasts of the North Sea
and the Baltic, with N. France to Cape Ushant. The absence
of any cold or warm current exerting direct influence upon the
coast-line of this sub-region causes a very gradual change in the
conditions of life as we move either southward or northward.
The fauna of the British seas contains a decided mixture of
northern and southern forms. ‘The following are among the
common Boreal species which attain their southward range on
our coasts: Tectura testudinalis Mull. (to Dublin Bay and
Scarborough), Zrichotropis borealis Brod. (to the Dogger Bank),
Margarita helicina Fabr. (to Yorkshire and Dublin Bay), JZ.
groenlandica Chem. (western Scotland), Natica montacuti Forb.
(to Cornwall), Trophon truncatus Str. (to Tenby), Chiton mar-
moreus Fabr. (to Dublin Bay and Scarborough). Buceinwm
undatum and Littorina littorea become very scarce on our extreme
south-western coasts. Among Lusitanian species which reach our
coasts are Gibbula magus L. (to Orkney and Shetland Islands),
Phasianella pullus L. (to Caithness), Galerus chinensis L. (to
Milford Haven), Galeomma Turtoni Turt. (to Weymouth), Car-
dium aculeatum L. (to Isle of Man), Solen vagina L. (to north
Ireland).
It appears from the Mollusca of our Crag formations that at
the time of their deposition the temperature of our seas must
have been considerably warmer than it is now. ‘Thus in the
Crag we find many species and even genera (e.g. Mitra, Fossarus,
Triton, Vermetus, Ringicula, Chama) which now occur no farther
366 LUSITAINAN SUB-REGION CHAP.
north than the southern coasts of the Channel, the west of
France, and the Mediterranean.
The Baltic, a sea specially lable to violent changes of tem-
perature, with a large admixture of fresh water at its eastern
end, appears to possess only about 65 species in all. More than
50 genera occurring on the western coasts of Denmark do not
enter the Sound. In the eastern portion of the Baltic marine
and fresh-water species live together (p. 12).
(4) The Lusitanian Sub-region extends from Cape Ushant
in the north to Cape Juby (lat. 28°) in the south, and includes
the whole of the Mediterranean, as well as the Azores, Canaries,
and Madeira groups.
The English Channel acts as an effectual barrier to the
northward extension of many species; as many as 81 species
which occur in western France do not reach British coasts
(P. Fischer). At the same time, the western coasts of France
are rather intermediate between the two sub-regions than
distinctly Lusitanian, for between 50 and 60 Mediterranean
genera do not occur on those coasts.
The Mediterranean itself is exceedingly rich in species, about
1200 in all (including deep-water species) being known. A
certain number of these belong to tropical genera which here
find their northern limit, e.g. Fasciolaria, Cancellaria, Sigaretus,
Siliquaria, Chama, Spondylus. Here too occur Carinaria,
Lobiger, Oxynoe, Pedicularia, Cypraea, Marginella, Mitra, Dolium,
Cassis, Cassidaria, Pisania, Huthria, Vermetus, Argonauta, and
many others. A few Celtic and even Boreal species, which occur
on the western coasts of Morocco, do not enter the Mediterranean.
Among these are Purpura lapillus, Helcion pellucidum, and
Tellina balthica. Halia, a rare West African genus akin to
Pleurotoma, is found in Cadiz Bay, and the West African Cym-
biwm occurs on the Spanish coasts as far as Malaga.
The Black Sea, whose northern and western coasts are
exceedingly cold, is comparatively poor in species. The Sea of
Azof is chiefly characterised by forms of Cardiwm.
(5) The West African Sub-region extends from Cape Juby to
a point probably not very far south of lat. 80° S., the cold cur-
rent which sweeps up from the Pole probably limiting the south-
ward extension of tropical species on this side of Africa, while
the warm Mozambique current on the eastern side permits the ~
xu WEST AND SOUTH AFRICAN SUB-REGIONS 367
spread of many Indo-Pacific species almost as far south as the
Cape. Owing to its extreme unhealthiness, and the absence of
harbours, the sub-region is very ttle known.
The principal genera are Cymbium, Pleurotoma, Marginella,
Terebra, Mitra, Aygaronia, Murex, Cancellaria, Purpura, Pseud-
oliva, Natica, Tellina, Lucina, Tugonia, Sehizodesma, and Arca.
Studer has enumerated as many as 55 species common to West
Africa and the opposite American shores. The north and south
equatorial currents, which circulate in this part of the Atlantic,
probably transport the larvae from one coast to the other. Pur-
pura coronata Lam., a characteristic West African species, is
represented by a well-marked variety in Demerara.
The Mollusca of St. Helena (178 known species) most
resemble those of the West Indies, 50 per cent being common,
while 30 per cent are common to the Mediterranean. From
Ascension Island only 33 species are known, which in their
general relations resemble those of St. Helena.!
(6) The South African Sub-region extends along the coast
from about lat. 80° on the west, to about East London on the
east. Mr. G. B. Sowerby enumerates 740 species from ‘South
Africa,’ but includes in this lst Natal species, which more prop-
erly belong to the Indo-Pacific fauna. Of these 740, 323 are
pecuhar, while 67 also occur in European seas, some being
familiar on our own shores. It is remarkable to find in a sub-
region separated from ourselves by the whole width of the tropics,
such well-known forms as Mangilia costata Don., WM. septangularis
Mont., Cylichna cylindracea Penn., Pholas dactylus L., Solen
marginatus Pult., Cultellus pellucidus Penn., Ceratisolen legumen
L., Lutraria oblonga Chem., Tellina fabula Gmel., 7. tenuis Da C.,
Modiolaria discors L., and many others.
The leading genera are Huthria, Triton, Cominella, Bullia,
Nassa, Cypraeovula, Oxystele, Fissurella, Fissurellidaea, Patella,
and Chiton.
The Mollusea of Kerguelen Island and the Marion and
Crozets groups show relationship partly with South America,
partly with the Cape, and partly with South Australia and New
Zealand, thus showing some trace of a circumpolar antarctic
fauna corresponding to, but not nearly so well marked as that of
the circumpolar arctic sub-region. Among the remarkable forms
1K. A. Smith, P. Z. S. 1890, pp. 247, 317.
368 INDO-PACIFIC REGION CHAP.
discovered off Kerguelen are Neobuccinum and a sub-genus of
Struthiolaria (Perissodonta).
B. The Indo-Pacific Region
includes the whole of the coast-line of the Indian and western
Pacific oceans, from about East London in South Africa to the
north of Niphon (lat. 42°) in Japan, with the Red Sea and Persian
Gulf, the whole of the Indo-Malay Archipelago, Polynesia to the
Sandwich Islands in the north-east, and Easter Island in the
south-east, and Australia to Swan River in the west, and to
Sandy Cape and Lord Howe’s Island in the east. It is especially
the region of coral reefs, which furnish so favourite a home of
the Mollusea, and which are entirely absent from the Atlantic
Region.
(1) The Indo-Pacific Sub-region proper (which includes the
whole of this region except that part defined below as the Jap-
anese Sub-region) is by far the richest in the world. The
marine Mollusca of the Philivpines alone (in some respects the
nucleus of the whole region) have been estimated at between
5000 and 6000 species, and Jousseaume estimates Red Sea
species at about 1000. Some prominent genera are very rich
in species. Garrett enumerates from Polynesia 81 species of
Conus, 60 of which occur on the Viti Is., 21 on the Sandwich
Is., and only 14 on the Marquesas, where coral reefs are almost
absent; 82 species of Cypraea, Viti Is. 44, Sandwich Is. 31,
Marquesas only 18; 167 species of Mitra (besides 29 recorded
by others), Viti Is. 120, Sandwich Is. 86, Marquesas 7. Of 50
existing species of Strombus, 39 occur in this region, and 10 out
of 11 Hburna.
The following important genera are quite peculiar to the
region: Nautilus, several forms of Purpuridae, e.g. Rapana,
Magilus, Rapa, Melapium, and Ricinula ; Tudicla, several forms
of Strombidae, e.g. Rostellaria, Terebellum, Pteroceras, and
Rimella ; Cithara, Melo, Neritopsis, Stomatia, Malleus, Vulsella,
Cucullaea, Tridacna, Hippopus, Libitina, Glaucomya, Anatina,
Aspergillum, and many others.
The number of species common to the Red Sea and
Mediterranean is exceedingly small, some authorities even deny-
ing the existence of a single common species. The present
XII JAPANESE SUB-REGION — AUSTRALIAN REGION 369
author, from an examination of the shells dredged by Mac-
Andrew at Suez, regarded 17 species as common, and Mr. E. A.
Smith has confirmed this view with regard to 8 of the species in
question.t. The Mollusca occurring in Post-pliocene beds at Suez
show that Mediterranean species lived there in comparatively
recent geological times.
The opening of the Suez Canal appears to have already
induced several species to start on their travels from the Medi-
terranean to the Red Sea and vice verséd. Two Red Sea species
(Mactra olorina Phil., Mytilus variabilis Ky.) had in 1882 estab-
lished themselves at Port Said, while two Mediterranean species
(Pholas dactylus L., Solen vagina L.) had reached Ismailia.?
(2) The Japanese Sub-region consists of the Japanese Islands
to Niphon, together with Corea and a stretch of adjacent main-
land coast of unknown extent. The warm Kuro Siwo current,
sweeping up between Luzon and Formosa, permits tropical species
to extend much farther north than on the opposite shores of
America, where a cold polar current keeps them back. Ds
dorso-lateral ; tentacular arms retrac- pocket into which the tentacu-
tile; two first dorsal arms in the 4" atm is retracted.
male hectocotylised ; gladius narrow, half as long as the body.—
World-wide.
Principal genera: Sepiola, dorsal mantle connected with the
head by a broad cervical band, ventral mantle with the funnel by
a ridge fitting into a groove; Rossia, dorsal mantle supported
by a ridge, arms with never more than four rows of acetabula:
Inioteuthis, Stoloteuthis, Nectoteuthis, and Promachoteuthis.
Fam. 2. Sepiadariidae. — Fins not as long as the body, mantle
united to the head on the dorsal side, fourth left arm in the
male hectocotylised; no gladius. Principal genera, Sepadarium,
Sepioloidea. — Chiefly Pacific Ocean.
Fam. 3. Idioseptidae.— Fins very small, terminal; fourth
pair of arms in the male hectocotylised, bare of suckers.
The only genus, Idiosepion, with a single species CL. pyg-
maeum Stp.) is from the Indian Ocean, and is the smallest
known Cephalopod, measuring only about 15 mm. in length.
Fam. 4. Loliginidae. — Body rather long, fins varying in size,
tentacular arms partially retractile, gladius as long as the back,
pointed in front, shaft keeled on the ventral side. — World-wide.
Loligo proper has a pointed body with triangular posterior
fins united behind; sessile arms with two rows of acetabula,
L |
1 uvéw, Close the eyes; dis, sight; contrasted with Oigopsidae (oiyw, open).
390 DECAPODA CHAP.
tentacular arms with four; fourth left arm hectocotylised at the
tip ; funnel attached to the head. Other genera are Loliguncula,
Sepioteuthis, and Loliolus. Belemnosepia, Beloteuthis, Leptoteu-
this, and Phylloteuthis are fossil genera only, differing in the
shape of the gladius.
(b) Oigopsidae: cornea more or less open; species pelagic.
Fam. 5. Ommastrephidae. — Body cylindrical, fins generally
terminal, united together, regularly rhomboidal, sessile arms
with varying number of rows of acetabula, mantle connexions
elaborate; gladius horny, narrow lanceolate, with a hollow
cone at the posterior end. — World-wide.
Ommastrephes proper has a natatory web on the sessile arms ;
the wrist of each club has a series of acetabula with correspond-
ing cushions on the other wrist. In Thysanoteuthis (often made
a separate family) the sessile arms have two rows of cirrhi, with
lateral expansions of the skin; fins as long as the body. In
Fic. 250.— Architeuthis princeps, Verr., E. America: /, Right fin; fw, funnel; /.c,
fixing cushions and acetabula on the tentacular arms (¢, ¢). (After Verrill, x ds.)
Architeuthis, to which belong the largest Cephalopoda known,
the fins together are shaped like a broad arrow-head ; acetabula
of sessile arms strongly denticulate ; tentacular arms very long,
with equidistant pairs of acetabula and fixing cushions through-
out their entire length, and a group of the same at the base of
the club. The acetabula and cushions correspond on the oppos-
ing tentacles, and enable them to pull together. Other genera
are Dosidicus, Todarodes, Illex, Bathyteuthis and Mastigoteuthis.
Fam. 6. Onychoteuthidae.— Body cylindrical, fins terminal or
lateral, mantle-locking apparatus elaborate, tentacular arms very
long, sessile or tentacular arms furnished with retractile hooks,
gladius lanceolate, with a terminal cone.— World-wide.
The prehensile apparatus of Cephalopoda reaches its maxi-
mum of power and singularity in this family. In Onychia, Onycho-
XIII DECAPODA 391
teuthis and Ancistroteuthis, the sessile arms have acetabula only,
in Gonatus and Abralia they have hooks as well, while in
Verania, Ancistrochirus and Enoploteuthis, the sessile arms have
hooks only. The number of rows of hooks or acetabula varies
with the different genera.
Fam. 7. Chiroteuthidae.— Head nearly as large as the body;
fins terminal, tentacular arms very long,
sessile arms slightly webbed, acetabula
denticulated; mantle-supports consist-
ing of cartilaginous ridges on the
mantle, which fit into corresponding
depressions on the tunnel, gladius ex-
panded at each end. — Atlantic Ocean.
The six dorsal arms in Histioteuthis
are united by a broad web, while in
Histiopsis the web only reaches half
way up the arm. In Chiroteuthis the
tentacular arms have scattered sessile
suckers throughout their whole length,
and four rows of very long peduncu-
late suckers on the clubs.
Fam. 8. Cranchiidae.— Head small,
body rounded, barrel-shaped, fins termi-
nal, eyes often very large, sessile arms
short, tentacular arms long, thread-like.
— World-wide.
Cranchia proper has the tentacular
clubs finned, with eight rows of suck-
ers, body sometimes covered with warty
tubercles. Loligopsis has a very atten-
uated body, with fins terminally united;
some species are spotted with colour, Beer cree aeenadiles
or have rows of tubercles on the ventral, 7, fins; ¢, ¢, tentacular
side. TYaonius (Fig. 251) is doubtfully a™ms. (After Hoyle, x 3.)
distinct from Loligopsis.
Order Tetrabranchiata
Cephalopoda with four branchiae and four kidneys; animal
inhabiting the last chamber of an external multilocular shell ;
392 CEPHALOPODA — TETRABRANCHIATA CHAP.
funnel consisting of two separate lobes; tentacles numerous,
without suckers or hooks; no ink-sac.
The shell consists of two layers, the outer being porcellanous,
and the inner, as well as the walls of the chambers or septa,
nacreous. The septa vary greatly in shape. In most of the
Nautiloidea they are regularly curved, as in Nautilus, or
straight, as in Orthoceras, but in the Ammonoidea they are often
exceedingly complex. The edge of the septum, where it unites
with the shell-wall, is called the suture, and the sutural line,
which is not seen until the porcellanous layer is removed, varies
in shape with the septum.
The septa are traversed by a membranous tube known as the
stphunele, which in Nautilus is said by Owen to connect ulti-
mately with the pericardium. ‘The septal necks, or short tubular
s&s.
cerasa Scaphites with
- the first whorls dis-
united. Macrosca-
phites (Fig. 259, B)
is similar, but with
Fic. 260.—A, Scaphites aequalis Sowb., Cretaceous; B, the first whorls
Crioceras bifurcatum Quenst., Cretaceous. (From Zittel.)
sis Ail
il
my
OU : {
(
an |
pl
if
united and not con-
cealed. Turrilites (Fig. 259, A) is turreted and sinistral, while
Baculites is quite straight, with a long body-chamber.
CHAPTER XIV
CLASS GASTEROPODA — AMPHINEURA AND PROSOBRANCHIATA
Order I. Amphineura
BILATERALLY symmetrical Mollusca, anus at the terminal
end of the body, dorsal tegument more or less furnished with
spicules.
Sub-order 1. Polyplacophora (Chitons ).— Foot co-extensive
with ventral surface of the body, dorsum with eight transverse
plates, articulated (except in Chitonellus), a row of ctenidia on
each side between the mantle and the foot. Silurian —
The Chitons are found in all parts of the world, ranging in
size from a length of about half an inch to six inches or more in
the giant Cryptochiton. Although in the main sub-littoral, they
occur at very great depths; the Challenger dredged Leptochiton
benthus Hadd. at 2300 fathoms. Chiton Polit exceptionally
occurs at Malta—teste MacAndrew—above sea margin, but
within reach of the ripple. As a rule, the Chitons live in con-
cealment, on the under surface of stones or in deep and narrow
fissures in the rocks. When the stone to which they are
attached is turned over, they crawl slowly to the side which is
not exposed, as if disliking the light. An undescribed species,
however, which I took at Panama, crawled quite as fast as an
ordinary snail. Chiton fulvus Wood, apparently is accustomed
to crawl with some rapidity. MacAndrew took it in abundance
on his anchor chain in Vigo Bay every time his yacht was got
under weigh. He also found it crawling in sand on the shore, to
which habit is no doubt due its extreme cleanness and freedom
from the foreign growths which are so characteristic of many of
the species. When detached a Chiton contracts the muscles of
the whole body, and rolls up into a ball like a wood-louse.
400
CHAP. XIV
POLY PLACOPHORA 401
The Polyplacophora are characterised, externally, by their
usually articulated shell of eight plates or valves, which is
surrounded and partly kept in position
by a muscular girdle. These plates over-
lap like tiles on a roof in such a way that
the posterior edge of the first, cephalic,
or anterior valve projects over the an-
terior edge of the succeeding valve, which
in its turn overlaps the next, and so on
Fig. 262. — Valves of
Chitonellus separated
out (anterior valve
uppermost): a, a, ar-
ticulamentum; ¢, ¢,
tegmentum. x2,
throughout. Seven-
valved monstrosities
very rarely occur.
A certain portion
of each valve is coy-
ered either by the
girdle or by the valve
next anterior to it.
This portion, which is
whitish in colour and
non-porous in struct-
ure, forms part of an Fic.261.—Valves of a Chiton
inner layer which peparated 10 show the
. various parts (anterior
underlies the rest of valve uppermost): a, a,
the substance of the articulamentum; Db, beak;
: j, jugum; pil, pl, pleura;
valve, and is called *% ¢, teomentum.
the articulamentum.
The external portion of the valves, or teg-
mentum, is generally more or less sculptured,
and is largely composed of chitin, impregnated
with salts of hme, thus answering more to a
cuticle than to a shell proper. It is very
porous, being pierced by a quantity of minute
holes of two sizes, known as megalopores and
micropores, which are connected together by
minute canals containing what is probably
fibrous or nerve tissue, the mouths of the pores
being occupied by sense organs connected
with these nerves. The tegmentum of the
six intermediate valves is generally divided
into three triangular areas by two more or less prominent ribs,
VOL. III
2D
402 POLYPLACOPHORA CHAP.
which diverge from the neighbourhood of the median beak or
umbo. The space enclosed between these ribs is known as the
median area or jugum, the other
two spaces as the lateral areas or
pleura. The ribs terminate with
the edge of the tegmentum, and
are not found on the articula-
mentum. In certain genera these
areas are either non-existent, or
are not distinctly marked. The
sculpture of the lateral areas
(which is, as a rule, much stronger
than that of the median area) will
generally be found to resemble
that of the anterior valve, which
has no proper median area. In
Lik the posterior valve the median
Fic. 263.—First, fourth, and eighth area is very small, while the
valves of a Chiton, showing 11, sculpture of the rest of the valve
laminae of insertion; n, n, notches;
s.l, s.l, sutural laminae. x 2. corresponds to that of the lateral
areas generally (see Fig. 261).
The articulamentum of the intermediate valves is divided into
two equal parts in the middle of the anterior edge, opposite to
the beak, by a senus. Each of the portions thus formed is again
divided by a notch or suture into two unequal parts, the anterior
of which is known as the sutural lamina, and is more or less
concealed by the valve in front of it, while the lateral part, or
lamina of insertion, is entirely concealed by the girdle. The
articulamenta of the anterior and posterior valves are either
simple or pierced by a series of notches (Fig. 263).
The girdle of the Chitonidae varies considerably in character.
Sometimes its upper surface is simply corneous or ecartilaginoid,
with no other sculpture than fine striae, at others it is densely
beset with spines or bristles, or tufted at intervals with bunches
of deciduous hairs; again it is marbled like shagreen or mossy
down, or covered with serpent-like scales. The width of the
girdle varies greatly, being sometimes very narrow, sometimes
entirely covering all the valves (Cryptochiton). As a rule, its
outer edge is continuous, but in Schizochiton it is sharply notched
over the anus.
XIV POLYPLACOPHORA 403
A description has already been given of the dorsal eyes in
Chiton (p. 187), the nervous system (p. 202), the branchiae (p.
154), the radula (p. 228), and the generative system (p. 126).
The recent Chitons are thus classified by Dr. W. H. Dall : —
SECTION I. CHITONES REGULARES. — Anterior and posterior
valves of similar character.
A. Leptoidea. — Insertion plates obsolete, or, if present,
unslit; Leptochiton, Hanleyia, Hemiarthrum, Microplaz.
B. Ischnoidea.— Insertion plates sharp, smooth, fissured ;
with eaves; Trachydermon, Callochiton, Tonicella, Schizo-
plax, Leptoplax, Chaetopleura, Spongiochiton, Ischnochi-
ton, Callistochiton.
C. Lophyroidea.— Insertion plates broad, pectinated, project-
Fic. 264.—Girdles of
various Chitonidae.
A, Radsia sulcata
Wood, x2) °8;
Maugeria = granu-
lata Gmel., x 3;
C,Enoplochiton
niger Barnes, x 3;
D, Acanthochiton
Fascicularis L., x
4; E, Tonicia fas-
tigiata Sowb., x 4.
ing backward; Chiton, Tonicia, Eudoxochiton, Craspedo-
chiton. .
D. Acanthoidea. — Insertion plates thrown forward; Sclero-
chiton, Acanthopleura, Dinoplax, Middendorffia, Nuttal-
lina, Arthuria, Phacellopleura.
SECTION II. CHITONES IRREGULARES. — Posterior valve
abnormal, or with a sinus behind.
E. Schizoidea.— Posterior valve fissured; Lorica, Schizochiton.
F. Placiphoroidea.— Posterior valve unslit, internally ridged,
umbo nearly terminal; Hnoplochiton, Ornithochiton,
Plaxiphora.
G. Mopaloidea. — Posterior valve with posterior sinus and
one slit on each side; Mopalia, Katherina, Acanthochi-
ton, Notoplax.
404 APLACOPHORA
CHAP.
H. Cryptoidea.— With double sutural laminae: Crypto-
conchus, Amicula, Oryptochiton.
Fic. 265.— Chitonellus fasciatus Quoy ; ant, anterior end.
I. Chitonelloidea. — Posterior valve funnel shaped; laminae
thrown forward; Chitonellus, Choneplacz.
Sub-order 2. Aplacophora. — Animal
vermiform, ioot
absent, or a mere groove, cuticle more or less
covered with spicules.
Fic. 266. — Neomenia ; ; :
carinata Tullb.: a, worm-like exterior being
anus; gr, ventral que to adaptation to sur-
groove; m, mouth. :
roundings. They have
hitherto been found chiefly in the N. Atlantic
and Mediterranean, generally at considerable
depths, and often associated with certain
polyps in a way which suggests a kind of
commensalism.
Fam. 1. Neomeniidae.— Foot a narrow
groove, intestinal tube without differentiated
liver, kidneys with common exterior orifice,
sexes united, ctenidia present or absent.
Genera: Neomenia (Fig. 266), Paramenia,
Proneomenia, Ismenia, Lepidomenia, Don-
dersia.
According to Marion, one of the principal
authorities on the group, the Aplacophora
are perhaps Amphineura whose development
has been arrested at an early stage, their
Fic. O61. Chabradeeae
nitidulum Lov.: 4a,
anus; m, mouth.
x 3.
Fam. 2. Chaetodermatidae.— Body cylindrical, no ventral
groove, liver a single sac, kidneys with separate orifices into the
branchial cloaca, two bipectinate ctenidia.
Chaetoderma (Fig. 267).
Single genus,
Order II. Prosobranchiata
Vises al loop twisted into a figure of 8 (streptoneurous ), right
XIV DIOTOCARDIA — RHIPIDOGLOSSA 405
half supra-intestinal, left half infra-intestinal; heart usually in
front of the branchia (ctenidium), which is generally single;
head with a single pair of tentacles; animal dioecious, usually
marine, more or less contained within a shell, operculum
generally present. Cambrian to present time.
Sub-order 1. Diotocardia. — Heart with two auricles (except
in the Docoglossa and Helicinidae), branchiae bipectinate, front
end free ; two kidneys, the genital gland opening into the right
(except in Neritidae); nervous system not cencentrated; no
proboscis or siphon, penis usually absent.
(a) DococLossa (p. 227).— Heart with a single auricle,
ventricle not traversed by the rectum, visceral sac not spiral,
shell widely conical, non-spiral, no operculum; radula very long,
with few hooked teeth in each row.
Fam. 1. Acmaeidae.— Left ctenidium alone occurring, free
on a long stalk. Cretaceous Principal genera: Pectino-
donta, front part of head much produced, radula 0 (1. 0. 1.) 0:
Acmaea (= Tectura), with sub-genera Collisella and Collisellina,
no accessory branchial ring, shell closely resembling that of
Patella, but generally with a distinct internal border; Seurria,
accessory branchial ring on the mantle.
Fam. 2. Lepetidae.— No ctenidia or accessory branchiae,
animal generally blind. Pliocene Principal genera:
Lepeta; Propilidium, apex with internal septum; Lepetella.
Fam. 3. Patellidae.— No ctenidia, the osphradial patch at
the base of each alone surviving, a circlet of secondary branchiae
between the mantle and sides of the foot. Ordovician
G.) Patellinae. —Three lateral teeth on each side, two of them
anterior. Principal genera: Patella, branchial circlet complete;
chief sections Patella proper, Seutellastra, Ancistromesus (A.
mexicana Brod., measures 8-14 in. long): Helcion, branchial
circlet interrupted in front; Zryblidiwm (Ordovician). — (i1.)
Nacellinae. —'Two developed laterals on each side, one anterior.
Genera: Nacella, branchial circlet complete; Helcioniseus, bran-
chial circlet interrupted in front.
(6) RaAIPIDOGLOsSA (p. 225). — Ventricle of the heart trav-
ersed by the rectum (except in Helicinidae), one of two ctenidia;
Jaw in two pieces, radula long, marginals multipled, rows curved.
Of all the Gasteropoda, this section of the Diotocardia
approach nearest to the Pelecypoda, particularly in the least
406 DIOTOCARDIA — RHIPIDOGLOSSA CHAP.
specialised forms. The auricle, the branchiae, and the kidneys
are in many cases paired, and more or less symmetrical. The
ventricle is generally traversed by the rectum, there is a long
labial commissure between the cerebral ganglia, special copula-
tive organs are usually absent, while the shell is often nacreous,
like those of Pelecypoda of a primitive type.
SECTION I. ZYGOBRANCHIATA. — Two ctenidia, shell with
apical or marginal slit or holes, corresponding to an anal tube
in the mantle (p. 265).
Fam. 1. Fissurellidae.— Two symmetrical ctenidia and kid-
neys, visceral mass conical, shell conical, elevated or depressed,
with a single anterior or apical slit or impression; no operculum.
Jurassic Ci.) Fissurellinae. Shell wholly external, apex
entirely removed by perforation, apical
callus not truncated posteriorly; cen-
tral tooth narrow. Genera: Fissurella
(Figs. 171, p. 261; 178, ps 26a) setae
suridea, Clypidella. (i.) Fissurelli-
dinae. Shell partly internal, otherwise
as in (i.); central tooth broad, mantle
more or less reflected over the shell,
apical hole very wide. Genera: F%s-
surellidaea, Pupillaea, Lucapina,Mega-
tebennus, Macroschisma, Lucapinella.
Gu.) Hmarginulinae. Shell usually
Fic. 268. — Scutus australis Lam., wholly external, apex usually not re-
Australia: m, m, mantle; sh, : ‘ ‘
shell. x 3. moved by perforation, sometimes with
internal septum, anal tube in a narrow
sht or sinus. Genera: Glyphis, externals of Fisswrella, but hole-
callus truncated behind; Pwncturella (sub-genera Cranopsis and
Fissurisepta), slit just anterior to the apex, a small internal
septum ; Zezdora, large internal septum as in Crepidula: Emar-
ginula, shell elevated, slit very narrow, on the anterior margin
Cn subg. Rimula, it is between the apex and the margin), radula
bilaterally asymmetrical; Subemarginula, margin indented by a
shallow groove; Scutus (= Parmophorus) shell oblong, depressed,
nicked in front, largely covered by the mantle.
Fam. 2. Haliotidae.— Right ctenidium the smaller, epipodial
line broad, profusely lobed; shell rather flattened, spire short, last
whorl very large, with a row of perforations on the left side,
XIV DIOTOCARDIA — RHIPIDOGLOSSA 407
which become successively obliterated; through these holes, the
posterior of which is anal, pass tentacular appendages of the
mantle; no operculum. Cretaceous . Single genus, Haliotis ;
principal sub-genera Padollus, Teinotis.
Fam. 38. Pleurotomariidae.— Central tooth single, narrow,
about 26 laterals, 60 to 70 uncini. Shell generally variously
trochiform, nacreous, operculate, with a rather broad marginal
sinus in the last whorl; as this sinus closes up it forms an “anal
fasciole”’ or “sinus band.” Cambrian Principal genera:
Scissurella, epipodial line with several long ciliated appendages at
each side, shell very small, slit open, sinus band extending nearly
to apex; Schismope, anal slit closed in the adult into an oblong
perforation; Murchisonia (Palaeozoic only), shell long, turreted,
whorls angulate or keeled with a sinus band; Odontomaria
(Palaeozoic only), shell
tubular, curved; Polytre-
maria (Carboniferous),
shell turbinate, slit a series
of small holes connected
by a passage; TZ'rochotoma,
shell trochiform, perfora-
tion consisting of two nar-
row holes united by a slit:
Pleurotomaria, branchiae
almost symmetrical, radula
as above, shell variously
spiral.
In Pleurotomaria we
have the case of a genus |
: Fia. 269. — Pleurotomaria adansoniana Cr. and
long supposed to be extinct. F., Tobago. x }.
More than 1100 fossil
species have been described, and within the last 38 years about
20 specimens, belonging to 5 species, have been discovered in
a living state.
Fam. 4. Bellerophontidae.— Shell nautiloid, spire generally
concealed, aperture large, sinus or perforations central (Fig. 179,
p- 266). Ordovician— Trias. Genera: Bellerophon, Trema-
tonotus, Cyrtolites.
SECTION II. AZYGOBRANCHIATA.— One ctenidium (the
left) present.
408 DIOTOCARDIA — RHIPIDOGLOSSA CHAP.
Fam. 1. Cocculinidae.— A single cervical ctenidium, foot
broad, no eyes, shell patelliform, with caducous spire. Single
genus, Cocculina. Deep water.
Fam. 2. Stomatellidae.— A single (left) ctenidium, front third
free, shell nacreous, spiral or patelliform, depressed, last whorl
large. Jurassic Genera: Stomatella (subg. Synaptocochlea,
Niphonia), shell depressed, spirally ribbed, spire short, operculum
present; Phaneta, fluviatile only, shell trochiform, imperforate,
last whorl keeled, sinuate in front; Stomatia, spire short, surface
tubercled or keeled, no operculum: Gena, shell haliotis-shaped,
surface smooth, aperture very large: Broderipia, shell patelli-
form, spiral apex often lost.
Fam. 38. Cyclostrematidae. — Tentacles ciliated, thread-like,
snout bilobed, foot truncated in front, angles produced into a
filament, shell depressed, umbilicated, not nacreous. Eocene
Principal genera: Cyclostrema, Teinostoma, Vitrinella.
Fam. 4. Liotiidae.— Epipodial line with a lobe behind each
eye-peduncle, shell solid, trochiform, longitudinally ribbed or
trellised, aperture round, operculum multispiral, hispid, corneous,
with a calcareous layer. Silurian Principal genera:
Liotia, Craspedostoma (Silurian), Crossostoma (Jurassic).
Fam. 5. Trochidae. — Snout short, broad, frontal lobes often
‘present, epipodial line furnished with cirrhi; shell nacreous,
variously spiral, operculum corneous, multispiral, nucleus central
(Hie, 182, p. 268). Silunan
G.) Trochinae.— Frontal lobes present,
lateral teeth (= side centrals) 5 only,
no jaws, peristome incomplete. Prin-
cipal genera: T'rochus (subg. Cardi-
nalia, Tectus, Infundibulum, Clan-
culus), Monodonta (subg. Diloma),
Fic. 270. — Monodonta canali- Cantharidus (subg. Bankivia, Tha-
ace Eeeean lotia), Gaza (subg. Microgaza), Cal-
logaza, Bembix, Chlorostoma. (ii.)
Gibbulinae. — Frontal lobes and jaws present, laterals often
more than 5, peristome incomplete. Principal genera: (i6-
bula (subg. Monilia, Aphanotrochus, Enida), Minolia, Circulus,
Trochiscus, Livona, Photinula, Margarita, Solariella, Calli
ostoma, Turcica, Basilissa, Euchelus (subg. Olivia, Perrinia).
(ili.) Delphinulinae.— No frontal lobes, jaws present; shell solid,
XIV DIOTOCARDIA — RHIPIDOGLOSSA 409
surface spirally lirate, scaly, spinose, umbilicate, peristome con-
tinuous. Single genus, Delphinula. (iv.) Umboniinae.— Eyes
pedunculate, left tentacle attached to a frontal appendage, mantle
reflected over edge of aperture, lateral teeth 6 on each side;
shell polished, peristome incomplete, umbilicus generally closed
by a callosity. Principal genera: Umbonium, Hthalia, Isanda,
Camitia, Umbonella, Chrysostoma.
Fam. 6. Turbinidae.— Epipodial line with slender cirrhi, snout
broad, short, eyes pedunculate at outer base of tentacles, a frontal
veil between tentacles; shell turbinate, solid, aperture continuous,
operculum solid, calcareous, usually paucispiral, convex exteriorly
(Fig. 182, p. 268). Silurian Ga.) Phastanellinae.—Shell
bulimoid, polished, not nacreous, coloured in patterns, aperture
oval. Single genus, Phasianella (Fig. 271). Gi.) Zurbininae.—
Shell very solid, nacreous within, aperture circular or long oval.
Principal genera, Turbo, whorls rounded above and below, spines,
if present, becoming more prominent with age, operculum smooth
or granulose, nucleus sub-central; subg. Callopoma, Ninella, Mar-
morostoma, Sarmaticus, Prisogaster ; Astralium, whorls flattened
above and below, spines, if present, becoming less prominent with
age, operculum oblong, often excavated at centre, last whorl large,
nucleus marginal or sub-marginal: subg. Lithopoma, Imperator,
Guildfordia, Bolma, Cyelocantha, Uvanilla,
Cookia, Pomaulax, Pachypoma. (iii.) Cyclo-
nematinae.—Shell nacreous, umbilicate,
operculum conical outside, whorls scalari-
form. Principal genera: Cyclonema, Hori-
ostoma (?), Amberleya (Silurian to Lias).
Cv.) Leptothyrinae.— Shell small, solid, de-
pressed, operculum nearly flat, nucleus sub-
central. Genera: Leptothyra, Collonia (?).
Fam. 7. Neritopsidae.— Tentacles wide
apart, long, eyes on short peduncles at the
outer base; shell solid, neritiform or naticoid,
aperture semi-lunar or oval; operculum
(Fig. 188, p- 269) thick, calcareous, ae ae se
spiral, exterior face smooth, interior face tralis Gmel., Australia.
divided into two unequal parts, with a broad
median appendage. Devonian Principal genera: Neri-
topsis (one recent species), Vaticopsis (Devonian to Miocene).
410 DIOTOCARDIA — RHIPIDOGLOSSA CHAP.
Fam. 8. Macluritidae.—Shell discoidal, whorls few, longi-
tudinally grooved behind, right side convex, deeply umbilicated,
left side flat ; operculum very thick, nucleus excentrical, internal
face with two apophyses, one very large. The general appearance
is more that of an inequivalve bivalve, such as Reguienca, than of
a spiral gasteropod. Palaeozoic Single genus, Maclurea.
Fam. 9. Neritidae.—Snout short, tentacles long, eyes pedun-
culate at their outer base, branchia triangular, free at the front
end, epipodium without cirrhi, penis near the right tentacle;
shell solid, imperforate, turbinate to almost patelliform, spire
short, internal partitions absorbed (p. 168), columellar region
broad, edge simple or dentate, operculum calcareous, spiral or
non-spiral, with prominent apophyses on the interior face, one
of which locks behind the columellar ip. Jurassic Prin-
cipal genera: Nerita (Fig. 18, p. 17); Neritina (chiefly brackish
water and fluviatile), sub-genus Clithon, usually coronated with
spines; Velates (Tertiary), Neritoma (Jurassic), Detanira (Cre-
taceous), Septaria (= Navicella), shell more or less narrowly
patelliform, with terminal apex, aperture very large, with a
broad columellar septum, operculum too small for the aperture,
more or less covered by the integument of the foot; fluviatile
only; Pileolus (Jurassic to Cretaceous ).
Fam. 10. Hydrocenidae.— Branchia replaced by a pulmonary
chamber, eyes at the outer base of the tentacles, marginals of
the radula very oblique, centrals often wanting; shell small,
conical, whorls convex, operculum calcareous, with a prominent
apophysis. Recent. Principal genera: Hydrocena, Georissa.
Fam. 11. Helicinidae.—Branchia replaced by a pulmonary
chamber, heart with one auricle; shell globular, with a short
spire, internal partitions absorbed; operculum without apophysis.
Carboniferous Principal genera: Helicina (Fig. 188, p.
21; subg. Alcadia, Schasicheila, Heudeia, Calybium), Eutrocha-
tella (subg. Lucidella), Stoastoma, Bourcieria, Dawsonella (Car-
boniferous ).
Fam. 12. Proserpinidae.— Branchia replaced by a pulmonary
chamber, mantle partly reflected over the shell, eyes sessile;
shell depressed, discoidal, columella folded or truncated at the
base, whorls with one or more internal plicae, internal partitions
absorbed, no operculum. Eocene Single genus; Proser-
pina, subg. Proserpinella, Cyane, Dimorphoptychia (Eocene),
and Ceres (Fig. 180, p. 21).
XIV MONOTOCARDIA — TAENIOGLOSSA 4II
Sub-order II. Monotocardia. — Heart with one auricle, one
ctenidium (the left), monopectinate, fused with the mantle
(except in Valvata), one kidney, not receiving the genital
products, nervous system somewhat concentrated, proboscis and
penis usually present.
(a) PTENOGLosSA. — Radula with formula «#.o., teeth
similar throughout, outermost largest (p. 224).
Fam. 1. Lanthinidae. — Snout prominent, blunt, no eyes, shell
helicoid, fragile, bluish, no operculum; eggs carried on a raft of
vesicles attached to the foot (Fig. 42, p. 126). Pelagic only.
Pliocene Genera: lanthina, Recluzia.
Fam. 2. Scalariidae. — Shell long, turriculate, whorls often
partly uncoiled, with longitudinal ribs and prominent lamellae,
aperture circular, operculum spiral, corneous, animal carnivorous.
Ordovician Principal genera: Scalaria, Hglisia, Elas-
moneura (Silurian), Holopella (Silurian to Trias), Ales.
(6) TAENIOGLOSSA. — Radula with normal formula 2.1.1.1.2,
marginals sometimes multiphed (p. 228).
Section I. PLatypopA.— Foot more or less flattened ven-
trally.
Fam. 1. Naticidae.— Foot very large, produced before and
behind, propodium reflected upon the head, eyes absent or buried
in the integument, central and lateral tooth of the radula tri-
cuspid, middle cusp strong; shell globular or auriform, outer lip
simple, operculum corneous or calcareous, nucleus excentrical.
Carboniferous Principal genera: atica, with many
sub-genera; Ampullina (Tertiary); Amaura; Deshayesia (Ter-
tiary); Sigaretus (Fig. 91, p. 186), shell auriform, last whorl very
large, operculum much too small for the aperture.
Fam. 2. Lamellariidae. — Mantle reflected over more or less
of the shell, shell delicate, no operculum. Eocene Prin-
cipal genera: Lamellaria, shell completely internal, transparent,
auriform; some species deposit their eggs on compound Ascidians
(p. 74); Velutina, shell almost entirely external, paucispiral,
with a thick periostracum; Marsenina, shell auriform, partly
internal; Onchidiopsis, shell a membranous plate, internal.
Fam. 38. Trichotropidae.— Branchial siphon short, eyes on
the outer side of the tentacles; radula closely allied to that of
Velutina; shell conical, last whorl rather large, periostracum
thick and hairy, operculum blunt claw-shaped, nucleus terminal.
Cretaceous Genera: T’richotropis, Torellia.
412 MONOTOCARDIA — TAENIOGLOSSA CHAP.
Fam. 4. Naricidae.— Tentacles broad in the middle, with
sessile eyes at the exterior base, propodium narrow, quadrangular,
a large epipodial veil on each side of the foot; shell naticoid,
cancellated, with velvety periostracum. Jurassic Single
genus: Narica.
Fam. 5. Xenophoridae. — Foot divided by a groove, anterior
portion the larger; central tooth heart-shaped, with blunt cusps,
lateral large, roughly triangular, marginals long, falciform; shell
trochiform, somewhat flattened, attaching various fragments
externally. Devonian Single genus, Xenophora (Figs.
25, 26, p. 64).
Fam. 6. Capulidae. — Ctenidium deeply and finely pectinate,
visceral sac scarcely spiral, penis long, behind the right tentacle;
shell roughly patelliform, with scarcely any spire, interior
polished, usually with a septum or internal plate of variable form,
no operculum. Devonian Principal genera (Fig. 155,
p- 248); Capulus, shell cap-shaped, no internal plate ; Platyceras
(Palaeozoic, see p. 76), Diaphorostoma (Palaeozoic), Addisonia
(?); Crucibulum, internal appendage funnel-shaped; Crepidula
Cncluding Crepipatella and Ergaea), shell
shpper-shaped, with a large septum ;
Calyptraea CGncluding Galerus and Tro-
chita), internal lamina semi-spiral.
Fam. 7. Hipponycidae.— Foot aborted,
animal sedentary, adductor-muscle shaped
like a horse’s hoof, fastened on the ven-
tral side to the region of attachment, or
Fre. 272.— Two specimens of tO @ thin calcareous plate which closes
Crepidula (marked a and the aperture like a valve; ventral side of
ae eee: ora patie body surrounded by a mantle with
papillose border, which corresponds mor-
phologically to the epipodia, head emerging between the dorsal
and ventral mantles. Shell thick, bluntly conical, surface rugose.
Eocene ——. Genera: Hipponyx; Mitrularia, a narrow half
funnel-shaped appendage within the shell.
Fam. 8. Solariidae. — Foot large, eyes sessile, near the outer
base of the tentacles, radula abnormal (p. 224); shell more or less
depressed, lip simple, umbilicus wide, margins often crenulated,
operculum variable. The proper position of the family is quite
uncertain. Ordovician Gi.) Solariinae. Genera: Sola-
XIV MONOTOCARDIA — TAENIOGLOSSA 413
rium, shell depressed, highly finished, angular at periphery,
operculum corneous, central tooth
absent, laterals and marginals num-
erous, long, and narrow; Platy-
schisma (Silurian). (ii.) Toriniinae.
Genera: Torinia, whorls usually
rounded, operculum (Fig. 185)
conically elevated, spiral externally,
central tooth present, marginals few,
edge pectinated; Omalazis. (iii.)
EHuomphalinae, shell planorbiform, ee:
whorls rounded. Genera: Huompha- yy. 973.— Solarium perspectivum
lus, Ophileta, Schizostoma, Hecyliom- Lam., Eastern Seas.
phalus (all Palaeozoic).
Fam. 9. Homalogyridae. — Tentacles absent, eyes sessile,
central tooth unicuspid on a quadrangular base, laterals and
marginals replaced by an oblong plate; shell very small, planor-
biform. Recent. Single genus: Homalogyra, whose true posi-
tion is uncertain.
Fam. 10. Littorinidae.— Proboscis short, broad, tentacles
long, eyes at their outer bases, penis behind the right tentacle;
reproduction oviparous or ovoviviparous, radula very long; shell
turbinate, solid, columella thickened, lip simple, operculum cor-
neous, nucleus excentrical. Jurassic Principal genera:
Inttorina (radula, Fig. 16, p. 20), Cremnoconchus (p. 16), Fossa-
rina; Tectarius, shell tubercled or spinose; Azsella, base slightly
concave ; Lacuna, shell thin, grooved behind the columellar lip.
Fam. 11. Fossaridae. — Shell turbinate, solid, small, white,
spirally ribbed, outer lip simple. Miocene Principal
genus, Fossarus.
Fam. 12. Cyclophoridae.—Ctenidium replaced by a pulmo-
nary sac, tentacles long, thread-like (radula, Fig. 17, p. 21); shell
variously spiral, peristome round, often reflected, operculum
circular. Terrestrial only. Cretaceous Ci.) Pomatiasinae,
shell high, conical, longitudinally striated, operculum consisting
of two laminae united together. Single genus, Pomatias. (il.)
Diplommatininae, shell more or less pupiform, peristome thick-
ened or reflected, often double. Genera: Diplommatina (subg.,
Nicida, Palaina, Pazillus, Arinia), shell dextral or sinistral,
small, columella often denticulated; Opisthostoma (Fig. 208, p.
AI4 MONOTOCARDIA — TAENIOGLOSSA CHAP.
309), last whorl disconnected, often reflected back upon the
spire. (ill.) Pupininae, shell more or less lustrous, bluntly
conical, lip with a channel above or below. Genera: Pupina
(subg., Registoma, Callia, Streptaulus, Pupinella, Anaulus), Hybo-
eystis (Fig. 205, p. 805), Cataulus, Coptochilus, Megalomastoma.
(iv.) Cyclophorinae, shell turbinate or depressed, operculum corne-
ous or calcareous. Genera: Alycaeus, Craspedopoma, Leptopoma,
Lagochilus, Cyclophorus (Fig. 206, p. 806; including Diadema,
Aulopoma, Ditropis, and others), Aperostoma Cncluding Cyrto-
toma and others), Cyathopoma, Pterocyclus (sube., Myxostoma,
Spiraculum, Opisthoporus, and Khiostoma (Fig. 180, p. 266),
Cyclotus, Cyclosurus, and Strophostoma.
Fam. 13. Cyclostomatidae.—Ctenidium replaced by a pul-
monary sac, tentacles obtuse, foot with a deep longitudinal me-
dian groove ; central tooth, lateral, and first marginal more or less
bluntly cusped, second marginal large, edge pectinate; shell
variously spiral, spire usually elevated,
aperture not quite circular; operculum
generally with an external calcare-
ous and an internal cartilaginoid lam-
ina, rarely corneous. ‘Terrestrial only.
Cretaceous Genera: Cyclostoma
(subg., Leonia, Tropidophora, Rochebrunia,
Fic. 274.— Cyclostoma cam- Georgia, Otopoma, Lathidion, Revoilia),
eee Pir, Mada- Qyelotopsis, Choanopoma (subg., Licina,
Jamaicia, Ctenopoma, Diplopoma, Adam-
stella), Cistula (subg., Chondropoma, Tudora), Omphalotropis
(sube., Realia, Cyclomorpha), Hainesia, Acroptychia.
Fam. 14. Actculidae.— Ctenidium replaced by a pulmonary
sac, tentacles cylindrical, pointed at the end, eyes behind their
base, foot long and narrow; central tooth and lateral very similar,
pinched in at the sides, external marginal broad, edge finely pec-
tinate ; shell small, acuminate, with a blunt spire, operculum
corneous. Terrestrial only. Tertiary Genus, Acicula
(= Acme).
Fam. 15. Truncatellidae.—Ctenidium replaced by a_pul-
monary sac, proboscis very long, eyes sessile, behind the base of
the tentacles, shell small, evenly cylindrical, apex truncated in
the adult. Eocene Genera: Truncatella (subg., Tahettia,
Blanfordia, and Tomichia), Geomelania (subg., Chittya and
Blandiella), Cecina (?).
XIV MONOTOCARDIA — TAENIOGLOSSA 415
Fam. 16. Rissoidae.— Eyes at the external base of the
tentacles, epipodium with filaments, operculigerous lobe with
appendages; central tooth pleated at the basal angles, lateral
large, bluntly multicuspid, marginals long, narrow, denticulate
at the edge; shell small, acuminate, often elaborately sculptured,
mouth entire or with a shallow canal, operculum corneous.
Marine or brackish water. Jurassic Principal genera:
Rissoa (subg., Folinia, Onoba, Alvania, Cingula, Nodulus, Anaba-
thron, Fenella, [ravadia, and others ), Scaliola (shell agglutinating
fragments of sand, etc.), Azssomna (lip thickened, operculum with
an apophysis as in Nerita), Barleeia, Paryphostoma (Eocene).
Fam. 17. Hydrobiidae. — Eyes at the outer base of the
tentacles, penis behind the right tentacle, prominent, operculiger-
ous lobe without filaments; radula rissoidan, central tooth often
with basal denticulations; shell more or less acuminate, small,
aperture entire, operculum corneous or calcareous. Brackish or
fresh water. Jurassic Principal genera: Baicalia, with
its various sub-genera (p. 299); Pomatiopsis, Hydrobia, Bithy-
nella, Micropyrgus (Tertiary), Pyrgula, Emmericia, Benedictia,
Lithoglyphus, Tanganyicia, Limnotrochus (?), Jullienia, Pachy-
drobia, Potamopyrgus, Littorinida, Amnicola, Fluminicola (subg.,
Gillia, Somatogyrus), Bithynia, Fossarulus (Tertiary ), Stenothyra.
Fam. 18. Assimineidae.—Ctenidium replaced by a pulmonary
sac, no true tentacles, eye-peduncles long, retractile ; radula that
of Hydrobia; shell small, conoidal, operculum corneous, nucleus
sub-lateral.. Eocene Genera: Assiminea, Acmella.
Fam. 19. Skeneidae. — Radula resembling that of Hydrobia ;
shell very small, depressed, widely umbilicated, operculum
corneous. Pleistocene Single genus, Skenea.
Fam. 20. Jeffreysiidae.— Mantle with two pointed ciliated
appendages in front, tentacles ciliated, eyes sessile, far behind
the base of the tentacles; marginal teeth sometimes absent;
shell small, thin, pellucid, whorls rather swollen, operculum with
marginal nucleus, divided by a rib on the inner face. Recent.
Genera: Jeffreysia, Dardania. Marine, living on algae.
Fam. 21. Litiopidae.— Epipodium with cirrhi on each side,
operculigerous lobe with appendages; radula rissoidan; shell
small, conical, columella truncated, operculum corneous. Eocene
Genera: Litiopa, living on the Sargasso weed, suspended
by a long filament; Alaba, Diala.
416 MONOTOCARDIA — TAENIOGLOSSA CHAP.
Fam. 22. Adeorbidae. — Radula essentially rissoidan; shell
depressed, circular or auriform, widely umbilicated, opercu-
lum corneous, paucispiral, nucleus excentrical. Pliocene
Principal genera: Adeorbis, Stenotis, Megalomphalus.
Fam. 23. Viviparidae.—Snout blunt, tentacles long, right
tentacle in the male deformed, pierced with a hole corresponding
to the aperture of the penis, two cervical lobes, the right being
siphonal, foot with an anterior transverse groove; teeth broad,
shallowly pectinate at the ends; shell turbinate, whorls more or
less rounded, aperture continuous, operculum corneous, nucleus
sub-lateral, with a false sub-central nucleus on the external face.
Animal ovoviviparous. Fresh water. Cretaceous Genera:
Vivipara (= Paludina), subg., Cleopatra, Melantho, Tulotoma;
Tylopoma (Tertiary), and Lnoplaz.
Fam. 24. Valvatidae. — Branchia exserted, bipectinate, carried
on the back of the neck, a filiform appendage (Fig. 66, p. 159) on
the right of the neck, penis under the right tentacle, prominent,
eyes sessile, behind the tentacles; radula like that of Vivipara;
shell small, turbinate or flattened, operculum corneous, nucleus
central. Fresh water. Jurassic——. Single genus, Valvata.
Fam. 25. Ampullariidae.—Snout with two tentacles, ten-
tacles proper very long, tapering, eyes prominently pedunculate,
two cervical lobes, the left siphonal, respiratory cavity divided
by a partition, a large branchia in the right chamber, the left
functioning as a pulmonary sac (Fig. 65, p. 158); radula large,
central tooth multicuspid, base broad, lateral and marginals falei-
form, simple or bicuspid; shell large, turbinate or flattened,
spire small, whorls rounded; operculum generally corneous,
nucleus sub-lateral, false nucleus as in Vivipara. Fresh water.
Cretaceous Single genus, Ampullaria (subg., Ceratodes,
Pachylabra, Asolene, Lanistes, and Meladomus).
Fam. 26. Cerithiidae.—Branchial siphon present, short,
eyes variable in position; central tooth small, evenly cusped,
lateral hollowed at base, multicuspid, marginals narrow; shell
long, turriculate, whorls many, generally tuberculate, varicose
or spiny, aperture sometimes strongly channelled; operculum
corneous, sub-circular, nucleus nearly central. Marine or
brackish water. Trias Principal genera: Triforis, shell
small, generally sinistral; Fastigiella, Cerithium (Fig. 12, p. 16),
Bittium, Potamides (subg., Tympanotomus, Pyrazus, Pirenella,
Telescopium, Cerithidea, Lampania, all brackish water), Diastoma
XIV MONOTOCARDIA — TAENIOGLOSSA AL
(Eocene), Cerithiopsis; Ceritella (Jurassic), Brachytrema
(Jurassic), and Planazis (subg., Quoyia and Holcostoma).
Fam. 27. Modulidae.—No siphon, radula of Cerithium; shell
with short spire, columella strongly toothed at the base, aperture
nearly circular. Recent. Single genus, Modulus.
Fam. 28. Nerinetdae.—Shell solid, long, sub-cylindrical,
aperture channelled, columella and interior of whorls with
continuous ridges, extending up the spire. Genera: Nerinea
(Trias to Cretaceous), Aptyziella (Jurassic).
Fam. 29. Melanitidae.— Border of mantle festooned, foot
broad, with an anterior groove, penis present; radula closely re-
sembling that of Cerithium; shell long, spiral, with a thick peri-
ostracum, surface with tubercles, ribs, or striae, suture shallow;
operculum corneous, paucispiral, nucleus excentrical.
Animal ovoviviparous. Fresh water. Cretaceous
Principal genera: Melania (with many sec-
tions or sub-genera), Pachychilus, Claviger (= Vibex),
Hemisinus, Pirena, Melanopsis, Tiphobia, Paludomus
(sube., Philopotamis, Tanalia, Stomatodon), Hant-
kenia (Eocene), Larina (?).
Fam. 30. Plewroceridae.— Mantle edge not fes-
tooned, no copulatory organ, otherwise like Melanii-
dae; operculum with nucleus sub-marginal. Animal
oviparous. Freshwater. Cretaceous Genera: ao. 975, — Me.
Pleurocera (including Jo, Fig. 12, p. 16, Angi- lnia con-
trema, Lithasia, Strephobasis), Goniobasis, Anculotus, As aaa
Gyrotoma.
Fam. 31. Pseudomelanitidae. —Shell resembling that of
Melaniidae, but marine. Genera: Pseudomelania, Loxonema,
Bourguetia, Macrochilus. Palaeozoic to Tertiary strata.
Fam. 82. Turritellidae.— Mantle with a siphonal fold on the
right side; radula variable (p. 224); shell long, whorls many,
slowly increasing in size, transversely ribbed or striated, aper-
ture small; operculum corneous, nucleus central. Jurassic :
Principal genera: Turritella, Mesalia, Protoma, Mathilda (?).
FAM. 33. Coectdae.—Tentacles long, eyes sessile at their base;
shell small, spiral in the young form, spire generally lost in the
adult, the shell becoming simply a straight or curved cylinder;
operculum corneous, multispiral. Eocene Single genus,
Coecum.
VOL, III 2E
A418 MONOTOCARDIA — TAENIOGLOSSA CHAP.
Fam. 34. Vermetidae.— Visceral sac greatly produced,
irregularly spiral, no copulatory organs (rvadula, Fig. 126, p.
223), shell tubular, irregularly coiled, last
whorls often free, aperture circular; operculum
corneous, circular, nucleus central. Carbo-
niferous Principal genera: Vermetus ;
Siliquaria (Fig 153, p. 248), a long fissure,
or series of holes, runs along a considerable
part of the shell, operculum with outer face
Pa, Dera spiral, elevated
showing thegradual FAM. 305. Strombidae.—F oot narrow, arched,
formation of septa; metapodium greatly produced, snout long, eye
a, apex; ap, aper- : -
ture; ss, first sep- peduncles long, thick, eyes elaborate, siphon
tum; ss’, second short, penis prominent, bifurcate; central tooth
septum. (After de. ; : :
Folin.) B, adult With strong median cusp, marginals falciform,
ep oeeaee slender, edge more or less denticulate; shell
,kanama. x 10. : ‘ ; : 5
solid, spire conical, outer lip generally dilated
into wings or digitations, channelled before and behind, a labial
sinus at the base, distinct from the anterior canal; operculum small
for the aperture, corneous, claw-shaped, edge notched. Lias
Genera: Strombus (Fig. 99, p. 200); Pereiraea (Miocene),
Pteroceras (Fig. 277; digitations of the outer lip very strong),
Rostellaria (spire produced, anterior canal very long), Rimella,
Pterodonta, Terebellum (base of shell truncate, spire short).
Fam. 36. Chenopodidae (= Aporrhaidae).— Foot flat; lateral
and marginal teeth not denticulate; shell resembling that of
Strombus, outer lip dilated, wing-like, no labial sinus. Jurassic
Genera: Chenopus (= Aporrhais, Diastema, Malaptera,
Harpagodes, Alaria (last four from Secondary strata).
Fam. 37. Struthiolariidae.—Radula allied to that of Strombus,
marginals occasionally multiplied; shell buccinoid, very solid,
outer lip thickened, canal short, operculum claw-shaped, notched,
nucleus terminal. Tertiary Single genus, Struthiolaria
(subg., Perissodonta, marginal teeth multipled).
Fam. 88. Cypraeidae.— Mantle with two large lateral lobes
reflected and meeting over the shell, siphon small; central and
lateral teeth bluntly tricuspid or multicuspid, laterals fairly
broad, edges cusped or finely pectinate; shell polished, solid,
spire generally concealed in the adult or overlaid with enamel,
aperture straight, narrow, nearly as long as the shell, toothed at
XIV MONOTOCARDIA — TAENIOGLOSSA 419
the sides, channelled at each end, labium inflected ; no opercu-
lum. Jurassic Genera: Ovula (including Amphiperas,
Transovula, Cyphoma, Radius, Simnia), Pedicularia, Cypraea
(with subg., Cypraeovula, Cypraedia, and Trivia), and KHrato.
Fam. 39. Dolvidae. — Foot expanded, wider and longer than
the shell, truncated and thickened in front, siphon very long and
narrow; central tooth with very strong median and small lateral
Fic. 277. — Three stages in the growth of Pteroceras rugosum Sowb., E. Indies,
showing the development of the ‘ fingers.’
“
and basal cusps, lateral and marginals bluntly falciform ; shell
ventricose, without varices, spire short, outer lip generally simple,
anterior canal rather wide, no operculum. Cretaceous :
Genera: Dolium (subg., Malea, outer lip thickened, denticulate,
reflected); Pirula, mantle with two lateral lobes reflected over
part of the shell, shell fig-shaped (Fig. 278).
Fam. 40. Cassididae. — Foot broad, siphon long (radula, Fig.
125, p. 223); shell ventricose, with varices, spire short, outer
lip reflected or thickened, anterior canal short, recurved narrow ;
operculum semilunar, with ribs radiating from a marginal
420 MONOTOCARDIA — TAENIOGLOSSA CHAP.
nucleus. Cretaceous Genera: Cassis (sube., Semicassis
and Cypraecassis), Morio (= Cassidaria), Oniscia.
Fam. 41. Columbellinidae.— Shell solid, ribbed, usually can-
cellated, with an oblique posterior canal, columella callous, more
or less reflected. Genera: Columbellina, Columbellaria, Zittelia,
Petersia, Alariopsis (?). Secondary strata only.
Fam. 42. Vritonidae. — Foot short, narrow; siphon short, not
prominent; radula allied to that of Cassididae; shell thick,
varicose; outer lip inflected and thickened, canal long, perios-
tracum often thick and hairy, operculum
corneous, nucleus terminal or sub-marginal.
Cretaceous . Genera: Triton (Fig. 191,
p- 275; subg., Epidromus, Plesiotriton, Sim-
pulum, Ranularia, Argobuccinum) ; Persona,
aperture toothed, narrow; columella reflected
upon the last whorl; Ranella, shell dorso-
ventrally compressed, generally with two con-
tinuous lateral varices, posterior canal present.
The position of the following four families
is doubtful: —
Fam. 45. Oocorythidae.— Siphon short,
foot broad, eyes absent, radula taenioglossate ;
Fig. 278. — Pima Dus- shell buecinoid or cassidiform, operculum cor-
sumieri Val., Philip-
pines. xd. neous, spiral. Recent. Single genus, Oocorys.
Fam. 44. Subulitidae. — Shell elongate,
fusiform, smooth; suture shallow, base truncate or rounded,
aperture channelled or notched. Ordovician to Trias. Genera:
Subulites, Fusispira, Huchrysallis.
Fam. 45. Seguenziidae.— Radula taenioglossate, shell trochi-
form, aperture channelled, columella twisted, operculum multi-
spiral, nucleus central. Pliocene Single genus, Seguenzza.
Fam. 46. Cheristidae.— Anterior tentacles united bya frontal
veil, posterior simple ; eyes absent, foot with tentaculae before and
behind; three central teeth, outer marginal with a basal plate;
shell helicoid, suture deep, peristome continuous, operculum
corneous, paucispiral. Pliocene Single genus, Choristes.
Section II. HretTERopopA. — Foot fin-shaped, not flat.
The Heteropoda are free-swimming Mollusca, being, like the
Pteropoda, Gasteropoda modified to suit their pelagic environ-
ment. Their nervous system is streptoneurous, and they are
XIV HETEROPODA 421
therefore probably derived from the Prosobranchiata, but they
are highly specialised forms. Pelseneer considers them far more
widely removed from the Streptoneura than the Pteropoda are
from the Euthyneura. They swim on the surface “upside
down,” z.e. with the ventral side uppermost.
The tissues and shell are transparent, permitting observation
of the internal organs. In the Pterotrachaeidae the foot takes
the form of a fan-shaped disc, usually furnished with a sucker.
The body is compressed at the posterior end, often with a ventral
“fin.” In Atlanta the foot consists of three very distinct parts:
a propodium, a mesopodium, on which is a small sucker, and a
metapodium, which carries the operculum. The branchiae are
carried on the visceral sac, and are free in Pterotrachaea, slightly
protected by the shell in Cartnaria, and entirely covered in
Atlanta ; absent altogether in Firoloida.
The head carries two tentacles (except in Pterotrachaea),
with large, highly organised eyes on short lobes at their outer
base. The alimentary tract consists of a long protrusible pro-
boscis, with a taenioglossate radula (Fig. 132, p. 227), a long
oesophagus, and a slightly flexured intestine. In Atlanta the
visceral sac is spiral and protected by a spiral planorbiform
shell; in Carinaria the visceral sac is small, conical, protected
by a very thin capuliform shell. There is no shell in Ptero-
trachaea or Firoloida.
The Heteropoda are dioecious. In the male there is a
flagellum behind the penis, which is near the middle of the
right side. Pterotrachaea lays long chains of granular eggs,
and has been noticed to produce a metre’s length in a day.
The eggs of Atlanta are isolated. The embryo has a deeply
bilobed velum.
Fam. 1. Pterotrachaeidae.— Body long, with a caudal “fin ;”
branchiae dorsal, free or partly protected by a shell; foot consist-
ing of a muscular disc, with or without a sucker.
Pterotrachaea proper has no mantle, shell, or tentacles. The
branchiae are disposed round the visceral sac, at the upper part
of which is the anus. In Firoloida the body is abruptly trun-
cated behind, with a long filiform segmented caudal appendage ;
visceral sac at the posterior end: fin-sucker present or absent in
both male and female. Cardiapoda resembles Carinaria, but the
visceral sac is more posterior and is only slightly protected by
A422 MONOTOCARDIA — GYMNOGLOSSA — RACHIGLOSSA CHAP.
a very small spiral shell. Carinaria (Fig. 279) has a rugose
translucent skin, visceral sac sub-median, apparently peduncu-
lated, covered by a capuliform shell. The larval shell, which
persists in the adult, is helicoid.
Fam. 2. Atlantidae.—Shell spiral, operculate, covering the
animal. Branchiae in a
dorsal cavity of the man-
tle; foot trilobed, with a
small sucker on the meso-
podium.
The shell of Atlanta
is discoidal and sharply
keeled, while that of Oxy-
gyrus is nautiloid, with the
Fic. 279.—Carinaria mediterranea Lam., spire concealed, no keel,
Naples: a, anus; 7, branchiae; f, foot; 7, aperture dilated.
testies fu mouths Zoemlss es 6) Coreg Toe
Radula and jaws absent;
proboscis prominent, sexes probably separate, penis present.
The section is probably artificial and unnecessary, the families
composing it being, in all probability, Taenioglossa which have
lost their radula in consequence of changed conditions of life
(pp. 79, 225).
Fam. 1. Hulimidae. — Proboscis very long, retractile, mantle
forming a siphonal fold; shell small, long, subulate, polished;
suture shallow, aperture continuous, operculum present or absent.
Animal often parasitic, sucking the juices of its host by its long
proboscis. ‘Trias Genera: Hulima (subg., Subularia Ar-
cuella, Apicalia, Mucronalia, Stiliferina, and others), Stilifer,
Scalenostoma, Niso, and Hoplopteron.
Fam. 2. Pyramidellidae. — Tentacles auriform, proboscis as in
Eulimidae,a prominent mentum or flap under the buccal orifice ;
shell usually small, conical; suture shallow, apical whorls (the
embryonic shell) sinistral (p. 250), operculum corneous, pauci-
spiral; nucleus excentrical. Trias Genera: Pyramidella
(subg., Syrnola, Otopleura, Chrysallida, Mumiola), Odostomia,
Eulimella, Murchisoniella, Turbonilla (subg., Dunkeria and
Cingulina.
(d) RACHIGLOSSA (p. 220).—Proboscis long, retractile ;
siphon distinct, radula without uncini, sometimes without
laterals ; teeth strongly cusped; shell generally wholly external.
XIV MONOTOCARDIA — RACHIGLOSSA 423
Fam. 1. Muricidae. — Eyes sessile at the outer base of the
tentacles, penis large, behind the right tentacle, radula within
the retractile proboscis, central tooth (Fig. 119, p. 220) with at
least three strong cusps, laterals plain; shell solid, more or less
tuberculate, spiny and varicose, anterior canal varying from a
mere notch to a long channel. Cretaceous Principal
genera: (i.) Muricinae, nucleus of operculum sub-terminal ; 7'ro-
phon, Typhis, Murex (with many subdivisions), Ocinebra Ginclud-
ing Cerastoma, Vitularia,and Hadriania), Urosalpinx, Eupleura,
Pseudomurea. (i.) Purpurinae, nucleus of operculum lateral ;
Rapana Gncluding Latiaris), Purpura (with subg., Cuma, Lopas,
Vexilla, and Pinaxia), Monoceros (including Chorus), Purpu-
rotdea (Secondary strata), Pentadactylus, Sistrum, Concholepas.
Fam. 2. Coralliophilidae. — Animal living in Madrepores,
resembling Purpura, radula absent; shell variously shaped,
often deformed or tubular, operculum that of Purpura, if
present. Miocene Principal genera: Rhizochilus, Co-
ralliophila, Leptoconchus, Magilus (Fig. 29, p. 75), Rapa.
Fam. 8. Columbellidae. — (Radula, Fig. 125, p. 222.) Shell
small, solid, fusiform, aperture narrow, canal short, outer lip
thickened. Miocene Single genus, Columbella (subg.,
Nitidella, Anachis, Meta, Strombina, Atilia, Conidea, Amphissa,
Mitrella, and others).
Fam. 4. Nasstdae.— Foot long and broad, often with
terminal appendages ; siphon long, eyes on outer base of tenta-
cles, central tooth of radula arched, multicuspid, lateral strongly
bicuspid, with small. denticles between the cusps; shell rather
small, buccinoid, columella more or less callous, outer lip thick-
ened, often toothed; operculum corneous, edges often toothed.
Miocene Principal genera: Massa (with many sections),
Amycla, Desmoulea, Cyclonassa, Canidia (subg., Clea and Nasso-
donta), Dorsanum, Bullia (= Buccinanops, Fig. 62, p. 185),
Truncaria.
Fam. 5. @uccinidae. — Siphon rather long, eyes at outer base
of tentacles; central tooth of radula with 5 to 7 cusps, laterals
bicuspid or tricuspid (Fig. 118, p. 220); shell more or less fusi-
form, thick, covered with a periostracum, canal of varying length,
outer lip simple or thickened; operculum corneous, nucleus
variable in position. Cretaceous Principal genera: Group
i. Chrysodomus (with sections Neptunea, Volutopsis, Pyrolofusus,
424 MONOTOCARDIA — RACHIGLOSSA CHAP.
Jumala), subg., Sipho; Siphonalia (subg., Kelletia). Group ii.
Tiomesus (= Buecinopsis). Group ii. Buccinum (Fig. 1B, p. 6;
subg., Volutharpa, Neobuccinum). Group iv. Cominella, Triton-
idea, Pisania, Huthria ; Anura (Miocene),
Genea (Pliocene), Metula, Engina. Group
v. Phos, Hindsia. Group vi. Dipsaceus (=
Hburna), Macron. Group vii. Pseudoliva.
Fam. 6. Turbinellidae. — Central tooth
of radula tricuspid, median cusp strong,
lateral bicuspid, cusps unequal (Fig. 117, p.
220) ; shell fusiform or pear-shaped, heavy,
canal often long, operculum corneous, claw-
shaped, nucleus terminal. Miocene .
Principal genera: Turbinella, Cynodonta,
Tudicla (subg., Streptosiphon) ; Piropsis
(Cretaceous), Perissolax (Cretaceous),
Fie. 280. — Turbinella pyr- Strepsidura (Eocene, subg., Whitneya),
um Lam., Ceylon. x 3. : :
Melapium, Fulgur (= Busycon, Fig. 150,
p. 249, including Sycotypus), Melongena (subg., Pugilina,
Myristica); Liostoma (Kocene), Hemifusus (subg., Megala-
tractus), Ptychatractus, Meyeria.
Fam. 7. Fasciolariidae.— Eyes at the outer base of the tenta-
cles (radula, Fig. 121, p. 221); shell
fusiform, spire long, canal often very
long, columella often with a fold at
the base; operculum corneous, nucleus
terminal. Cretaceous . Principal
genera: Fusus (including Sinistralia,
Aptyxis, Troschelia), with subg., Serri-
fusus (Cretaceous), Clavella (subg.
Thersites), Fasciolaria, Latirus (subg.
Polygona, Peristernia, Leucozonia, La-
gena; Mazzalina (Eocene), Chascax).
Fam. 8. Jlitridae.— Siphon rather
long, with anterior appendages, eyes
on the side of the tentacles, proboscis
very long; radula variable, laterals Fc. 281.— Latirus (Leucozonia)
‘ : cingulatus Wood, Panama.
sometimes lost (Fig. 120, p. 221);
shell fusiform, solid, spire more or less pointed, columella with
several prominent folds, the posterior the largest, aperture rather
XIV MONOTOCARDIA — RACHIGLOSSA 425
narrow, no operculum. Cretaceous
Mitra (with many sections), subg., Strigatella,
Mitreola, Mutyca, Dibaphus ; Plochelaea (Ter-
tiary), Thala; Turricula (with several sec-
tions), Cylindromitra, and Imbricaria.
Fam. 9. Volutidae.— Foot broad in front,
head laterally dilated into lobes, on which
are placed the sessile eyes ; siphon prominent,
with appendages at the base (radula, Fig. 122,
p. 221); shell thick, often shining, fusiform,
globular or cylindrical, columella projecting
anteriorly, with several folds, the anterior of
which is the largest, aperture notched, canal
not produced, operculum generally absent. Fic. 282.— Voluta ni-
Cretaceous Principal genera: Crypto- ee ae Ai:
chorda (Eocene), Zidona, Provocator, Guivil-
lea, Yetus (= Cymbium), Voluta (with many sections), Voluto-
lithes (chiefly Eocene), Volutolyria, Lyria, Enaeta, Volutomitra.
Fam. 10. Marginellidae.— Foot broad, siphon without ap-
pendages, mantle largely reflected over the shell; radula with-
out laterals, central tooth comb-like, cusps rather blunt; shell
oval or conoidal, polished, aperture narrow,
outer lip thickened, columella with many
folds; no operculum. Eocene Prin-
cipal genera: Marginella, with many sections
and so-called sub-genera; Persicula, Pachy-
bathron (?), Cystiseus, Microvoluta.
Fam. 11. Harpidae.— Foot large, with a
transverse groove, separating off a semi-lunar
propodium; mantle partly reflected over the
shell; shell ventricose, polished; spire short,
strongly longitudinally ribbed, ribs prolonged
over the suture, columella callous; no oper-
culum. Eocene Single genus, Harpa
Fg, 20; Olan go (subg Sia).
: : “Fam. 12. Olividae. — Propodium semi-
lunar, with a longitudinal groove above,
mesopodium reflected laterally over the shell; central tooth of
radula tricuspid on a very broad base, lateral simple, hooked ;
shell sub-cylindrical or fusiform, polished; aperture narrow,
Principal genera:
426 MONOTOCARDIA — TOXOGLOSSA
CHAP. XIV
operculum present or absent. Cretaceous
Principal
genera: Oliva (Figs. 283, and 98, p. 199);
Olivancillaria (including
lina).
with a large poison gland;
rous, exclusively marine.
the tentacles, shell subulate,
many whorled, operculum
with terminal nucleus.
Kocene Single genus,
Terebra, with several sec-
tions.
Fam. 2. Conidae.— Eyes
on outer side of tentacles,
siphon prominent; — shell
conical or fusiform, aperture
narrow. Cretaceous
Principal genera: Conus, shell solid, spire
short, aperture narrow, straight, internal par-
titions partly absorbed; Conorbis, Genotia
(with several sections, chiefly Tertiary),
Pusionella, Columbarium, Clavatula, Surcula,
Pleurotoma; Borsonia (Eocene), Drillia
(subg., Spirotropis), Bela, Mangilia (including
Daphnella, Clathurella, and others), Halia.
Fic. 284.—Terebra sub-
ulata L., Ceylon.
Tintricula and
Agaronia), Olivella, Ancilla (subg., Aneil-
(e) TOXOGLOSSA (p. 218).— Radula with
normal formula 1:0:1, teeth large ; oesophagus
animal carnivo-
Fam. 1. Terebridae.— Eyes at the end of
Fic. 7 285. — Pleuro-
toma tigrina Lam.,
E. Indies.
Fam. 8. Cancellariidae.— Proboscis short, usually no
radula, shell oval, columella strongly plicate; no operculum.
Cretaceous Single genus, Cancellaria
Trigonostoma, Admete).
(subg., Merica,
CHAPTER XV
CLASS GASTEROPODA (continued): OPISTHOBRANCHIATA AND
PULMONATA
Order III. Opisthobranchiata
VISCERAL loop not twisted (except in Actaeon) in a figure of
8 (Euthyneurous type, p. 203), auricle usually behind the ven-
tricle, ctenidium often replaced by secondary branchiae, pallial
cavity, if existing, more or less open, shell present or absent,
operculum absent (except in Actaeon), animal hermaphrodite,
with separate sexual openings, marine only. — Carboniferous to
present time.
The character of their nervous system decisively removes the
Opisthobranchiata from the Prosobranchiata, and approximates
them to the Pulmonata. Actaeon, however, which is strepto-
neurous, as well as possessing an operculate shell with prominent
spire, forms an interesting link with the Prosobranchiata. At
the opposite extreme to Actaeon stand forms like Siphonaria
and Gadinia, which are probably close links with the Pulmonata
(p. 19). The generative system of the whole group, which is,
as in the Basommatophora, of the hermaphrodite type, without
mutual fecundation, is another link of connexion with the
Pulmonata. The respiratory organs present the most varied
forms, sometimes consisting of one ctenidium (never two), some-
times of secondary branchiae, variously placed, while sometimes
no special organ exists.
The prolongation of the foot into lateral epipodia or parapodia
(possibly to aid in swimming), and the effect of the epipodia
upon the shell, according as they involve it completely or par-
tially, are among the most instructive features of the Opistho-
branchiata. If the epipodia are developed on the anterior
427
428 OPISTHOBRANCHIATA CHAP.
portion of the body, and do not become reflected, they may, as
in most Pteropoda Thecosomata, not directly affect the shell.
But when, as in the Tectibranchiata, the epipodia are medio-
lateral, and tend to envelope the shell, their effect may be
traced by a series of forms varying in proportion to the amount
of shell-surface covered by the epipodia. The two principal
lines along which modification takes place are the gradual
reduction of the spiral nature of the shell, and the gradual
lessening of its solidity. Both these changes are the direct
Fic. 286. — Illustrating the transition Fia. 287.—TIllustrating the gradual covering
of form in the shell of Tecti- of the shell in the Tectibranchiata by the
branchiata from the pointed spiral epipodia and mantle: A, Haminea; B,
to the almost flattened plate: A, Scaphander ; C, Aplustrum ; D, Aplysia;
Actaeon; B, Aplustrum; C, Cyli- E, Philine; c.d, cephalic disc; ep, ep,
chna; D, Atys; E, Philine; F, epipodia; sh, shell. (Not drawn to scale.)
Dolabella; G, Aplysia; H, Pleu-
robranchus. (Not drawn to scale.)
result of the additional protection afforded to the visceral mass
by the reflected epipodia, which renders the existence of a shell
less and less necessary. A precisely similar line of change is
seen in the Pulmonata, culminating in forms like Arion (p. 174).
The habits of life of the Opisthobranchiata are very varied. -
Some, especially the heavier types, burrow in sand, and are then
usually furnished with a broad cephalic disc, as a digging appa-
ratus; some (certain Bulla) flit about in shallow pools on mud
flats; others (Phyllirrhoe and the Pteropoda) swim freely in
the open sea; others (most Nudibranchiata) crawl slug-like on
sea-weeds or corallines, and in colour singularly harmonise with
XV OPISTHOBRANCHIATA: HABITS, CLASSIFICATION 429
their environment (p. 71 f.) ; others again (Siphonaria, Gadinia),
stick limpet-like to rocks between tide marks. As a rule, they
occur only in clean salt water, but Hmbletonia has been found in
the Victoria Docks at Rotherhithe, as well as in parts of the
Baltic, where the water has only 7 parts of salt in 1000, while
Limapontia occurs in nearly fresh water at Bornholm and
Gothland.
Their food varies greatly. As a rule, they are frugivorous,
but many cases of carnivorous habit occur. Seaphander has
been seen to swallow Dentalium six at a time, and in six hours
the shells of all were reduced to tiny fragments. Glawcus devours
the soft portions of the pelagic Porpita and Velella; Idalia
elegans eats its way into the test of Ascidians, and completely
buries itself in the body of its prey.!
The Opisthobranchiata may be classified as follows : —
| Bulloidea
A plysioidea
1. TECTIBRANCHIATA :
| © | Pleurobranchoidea
| \ Siphonarioidea
Opisthobranchiata ; 2. AscoGLossa
| 3. NUDIBRANCHIATA . j Ciaaclen alee
| | Holohepatica
| A. PaOren sk ' Thecosomata
rf
| Gymnosomata
Sub-order I. Tectibranchiata. — Right ctenidium usually
present, more or less concealed by the mantle fold, visceral
ganglia united by a. very long commissure, shell variable in
form, more or less enveloped in folds of the mantle and foot,
often becoming rudimentary.
SECTION I. BULLOIDEA. — Shell more or less spiral, internal
or external, epipodia more or less developed, a broad cephalic
disc, distinct from the dorsal region, usually no tentacles, eyes
sessile.
Fam. 1. Actaeonidae.— Shell spiral, solid, entirely covering
the animal; spire generally prominent, operculum corneous,
visceral loop streptoneurous, no epipodia, radula multiseriate,
teeth numerous, very small. Carboniferous Genera:
Actaeon (Fig. 286 A); Volvaria (Tertiary), Fortisia (Eocene)
1J. Power, Ann. Mag. N. H. (2) xx. p. 334; P.Z. 8. 1836, p. 113; Arch. Zool.
Exp. Gén. (3) i. 1898, p. 105.
430 TECTIBRANCHIATA CHAP.
Actaeonina (Carboniferous), Cylindrites (Secondary strata),
Actaeonella (Cretaceous).
Fam. 2. Tornatinidae.— Shell spiral, cylindrical, entirely
covering the animal; spire concealed, cephalic disc with two
large tentaculiform appendages behind, no radula. Genera:
Tornatina (= Utriculus), Volvula.
Fam. 8. Scaphandridae.—Shell more or less external, cover-
ing all or nearly all the animal, spire concealed, cephalic disc
simple or notched behind, epipodia well developed, radula with
first lateral very large, stomach sometimes with powerful gizzard.
Genera: Scaphander (Fig. 287 B); Sabatia (Pliocene), Smaragdi-
nella, Atys (Fig. 286 D), Cylichna (Fig. 286 C), Amphisphyra.
Fam. 4. Bullidae. shell external or partly internal, spire
quite or nearly hidden, cephalic disc broad, without appendages,
epipodia often large ; radula usually multiseriate. Genera: Bulla
(subg. Haminea), Acera, mantle with long filiform appendage,
epipodia touching over the shell; Cylindrobulla, Volvatella.
Fam. 5. Aplustridae. — Shell partly internal, overlaid by the
posterior part of the cephalic disc, spire not prominent, epipodia
reflected, tentacles auriform. Single genus, Aplustrum (Fig. 286
B; subg. Hydatina).
Fam. 6. Ringiculidae. — Shell small, solid, covering all the
animal; spire somewhat prominent, aperture narrow, plicated ;
peristome thick, sometimes channelled, cephalic disc with a kind
of posterior siphon. Genera: Ringicula ; Avellana (Cretaceous ).
Fam. 7. Gastropteridae.— Shell completely internal, nauti-
loid, small; epipodia very large, rounded, united behind; cephalic
disc simple. Single genus, Gastropteron.
Fam. 8. Philinidae.—Shell completely internal, thin, shghtly
spiral ; epipodia thick, cephalic disc large, thick, simple; stomach
usually with powerful gizzard. Genera: Philine (Fig. 287
E), Colpodaspis, Colobocephalus, Chelinodura, Phanerophthalmus,
Cryptophthalmus.
Fam. 9. Doridiidae.—Shell completely internal, a mere
pellicle with a small spiral nucleus, mantle with two posterior
lobes and a caudal filament, epipodia reflected. Single genus,
Doridium.
Section II. ApPLysIomIpEA. — Shell small, usually not spiral,
sometimes absent, no cephalic disc, head prominent, with two
pairs of tentacles, epipodia large, more or less reflected.
XV TECTIBRANCHIATA — ASCOGLOSSA 431
Fam. Aplysiidae.— Characters those of the section. Genera:
Aplysia (Fig. 287 D), shell arched, flattened, animal large (the
‘sea hare”); Dolabella, shell sub-triangular (Fig. 286 IF) ; Dola-
brifer, shell sub-quadrangular, not spiral ; Motarchus, shell micro-
scopic, spiral; Phyllaplysia, body very depressed, oval, no shell.
Section III. PLEUROBRANCHOIDEA.— Dorsal region pro-
tected by a wide notaewm or dorsal covering, or by a shell; no
epipodia, ctenidium large, external, between the right under
surface of the notaeum or shell and the foot; head short, shell
present or absent.
Fam. 1. Pleurobranchidae.— Shell internal or absent, notaeum
with spicules, radula multiseriate. Genera: Plewrobranchus
(Fig. 286 H), (?) Haliotinella, Pleurobranchaea, (?) Neda.
Fam. 2. Runeinidae.—Branchial lamellae few, under the
posterior right notaeum, no shell. Single genus, Auneina.
Fam. 3. Umbrellidae.—Shell external, depressed patelliform,
not covering all the animal; foot very thick, ctenidium large,
head depressed, small; radula multiseriate, teeth innumerable,
very small. Genera: Umbrella (Fig. 5A, p. 10), Zylodina.
SECTION IV. SIPHONARIOIDEA.— Shell patelliform, bran-
chia replaced wholly or in part by a pulmonary sac, pulmonary
orifice closed by a small lobe, radula multiseriate, teeth very
small.
Fam. Stphonariidae.— Characters those of the section.
Genera: Stphonaria (branchia as well as pulmonary sac), Gad-
tnia (no branchia). These genera, hitherto placed among the
Pulmonata, have been recently shown (see p. 19) to be modified
Opisthobranchiata.
Sub-order II. Ascoglossa.1— Branchia, mantle cavity, and
shell generally wanting, liver ramified, rami enclosed in external
papillae (cerata) or beneath the dorsal surface, kidney not com-
pact, branched ; radula with one series of strong teeth (Fig. 288),
worn out teeth at the front end not dropping off, but preserved
in a special sac (acxcs).
According to Bergh, the Ascoglossa form a link between the
Tectibranchiata, — especially the Aplysiidae and Bullidae —and
1 In deference to Bergh’s high authority, the position of a sub-order is here
given to the Ascoglossa. It may be doubted whether that position will stand the
test of further investigation, and whether the families concerned will not be added
to the Cladohepatie Nudibranchs.
432 ASCOGLOSSA — NUDIBRANCHIATA CHAP.
the Cladohepatie Nudibranchs, while the Pleurobranchidae form
a somewhat similar link between the Holohepatic Nudibranchs
and the other Tectibranchiata.
Fam. 1. Oxynoeidae+— Animal long, tentacles auriform,
epipodia large, simple, or wing-like, a ctenidium and branchial
chamber on right side, shell small, thin,
slightly spiral, not covering much of
the body. Genera: Oxynoe (= Lopho-
cercus), Lobiger.
Fam. 2. Hermaeidae.— Body de-
pressed, cerata in several rows, no
branchiae, no shell. Genera: Hermaea,
Phyllobranchus, Stiliger, Alderia.
Fig. 288.—Radula of one of Fam. 3. Elysiidae.— Body depressed,
cee viridis head rather elevated, tentacles auriform,
sides of body dilated into two large
wings, which enclose branches of the liver and sometimes fold
over the dorsal surface, no branchiae, no shell. Genera: Hlysia,
Thridachia, Placobranchus.
Fam. 4. Limapontiidae. — Body slug-like, liver scarcely
ramified, no branchiae, shell, or appendages. Genera: Lima-
pontia, Actaeonia, Cenia.
Sub-order III. Nudibranchiata. — Shell absent in the adult,
no ctenidium proper, or osphradium, cerata dorsal or dorso-lateral,
nervous system concentrated, kidney not compact, ramified, penis
retractile, jaws and radula usually present.
SECTION I. CLADOHEPATICA. — Cerata usually latero-dorsal,
elongated, or arborescent, buccal mass strong, jaws present, liver
generally ramified, rami generally entering the cerata.
Fam. 1. Aeolidiidae.— Body slug-like, head with tentacles
and rhinophores, dorsal area with rows of cerata, which usually
contain sting-cells, radula variable. Genera: Aeolis, Cratena,
Tergipes, Coryphella, Favorinus, Facelina, Flabellina, Fiona,
Glaucus, Janus, Hero, with many sub-genera.
Fam. 2. Tethymelibidae.— Body slug-lke, large, cerata very
large, no sting-cells, head large, cowl-shaped, no tentacles, rhino-
phores much foliated, no radula. Genera: Tethys, Melibe. The
cerata of Tethys, which are capable of independent movement
1 This family has also been classified with the Bulloidea and with the
Aplysioidea,
XV NUDIBRANCHIATA A33
when severed, have been described as parasitic worms. Tethys
feeds on molluscs and Crustacea.
Fam. 3. Lomanotidae. — Body slug-like, dorsum prominent,
undulating or lobed, with one row of small cerata, no tentacles,
rhinophores much foliated, radula with uncinated dentate
laterals. Single genus, Lomanotus.
Fam. 4. Dotonidae. — Body slug-like, small, two rows of
cerata, each ceras surrounded by a ring of tubercles, rhinophores
simple, radula uniseriate. Single genus, Doto.
Fam. 5. Dendronotidae.— Body slug-like, somewhat com-
pressed, two rows of arborescent cerata, no tentacles, frontal
margin with arborescent papillae, rhinophores arborescent, radula
multiseriate. Genera: Campaspe, Dendronotus.
Fam. 6. Bornellidae.—'Two rows of dorsal papillae, with
branchiform appendages at the base, rhinophores foliate, radula
multiseriate. Single genus, Bornella.
Fam. 7. Seyllaeidae.— Body oblong, compressed, two large
foliated cerata with branchial appendages on the inner side, no
tentacles, rhinophores large, radula multiseriate. Single genus,
Scyllaea.
Fam. 8. Phyllirrhoidae. — Body much compressed, with
bovine head and neck, tail tapering, no tentacles, rhinophores
simple, teeth few, no marginals. Single genus, Phyllirrhee.
Fam. 9. Pleurophyllidiidae.— Body elongate-oval, snout
broad, covered by an arched shield with lateral angles prolonged,
branchiae consisting of two rows of lamellae placed between the
notaeum and the foot, no tentacles, rhinophores short, hidden,
radula multiseriate. Single genus, Pleurophyllidia.
Fam. 10. Pleuroleuridae. — Animal resembling Pleurophyl-
lidia, but without the branchial lamellae. Single genus, Plew-
roleura.
Fam. 11. Tritoniidae.— Body long, two rows of unequal
arborescent cerata, rhinophores with ramose appendages, liver
not prolonged into the cerata. Genera: Tritonia, Marionia.
SECTION 2. HOLOHEPATICA. — Cerata medio-dorsal, retractile
or not, usually paucifoliate, liver never ramified, usually no Jaws.
Fam. 1. Dorididae. — Branchia consisting of a circle or semi-
circle of pinnate leaves united at the base, surrounding the anus,
almost always retractile into a cavity, rhinophores foliate, no
suctorial proboscis, radula multiseriate. Genera: Bathydoris,
VOL, III ZF
434 NUDIBRANCHIATA CHAP.
Hexabranchus, Archidoris (Fig. 289), Discodoris, Diaulula,
Cadlina, Centrodoris, Platydoris, Chro-
modoris, Miamira, with many sub-
genera.
Fam. 2. Doriopsidae.— Branchia and
rhinophores as in Dorididae, oral aper-
ture pore-shaped, suctorial, no radula.
Single genus, Doriopsis.
Fam. 3. Phyllidiidae.— Body oval,
depressed, leathery, a ring of branchial
lamellae, only interrupted by the head
and genital papilla, under the pallial
edge, oral aperture pore-shaped, suc-
Fre. 289.— Doris (Archidoris) torial, no radula. Genera: Phyllidia,
tuberculata L., Britain: ¢, Fyyeria. Bergh unites this and the
anus; 67, branchiae sur- : ; ;
rounding the anus; 7, male preceding family in the group Porosto-
Soe rh, rh, rhinophores. > q¢q which, with Fam. 1, form the
| group Dorididae eryptobranchiatae.
Fam. 4. Polyceridae.— Body slug-like, branchiae not retrac-
tile, usually surrounding the anus, rhinophores foliate, tentacles
sunple, radula variable, central tooth generally wanting. Genera:
Notodoris, Triopella, Aegires, Triopa, Issa, Triopha, Crimora, Theca-
cera, Polycerella, Palio, Polycera, Ohola, Trevelyana, Nembrotha,
Huplocamus, Plocamopherus, Kalinga.
Fam. 5. Goniodoridae. — Body oval, depressed, branchia mul-
tifolate, usually disposed in shape of a horse-shoe, rhinophores
folate, retractile or not, mouth with a large suctorial proboscis,
radula variable. Genera: Akiodoris, Doridunculus, Acanthodoris,
Adalaria, Lamellidoris, Calycidoris, Goniodoris, Idalia, Ancula,
Drepania.
Fam. 6. Corambidae. — Body otherwise Doris-like, but with
two posterior branchiae under the mantle edge, jaws present, no
central tooth, about five laterals. Single genus, Corambe (=
Hypobranchiaea). Bergh unites this and the two preceding
families in the group Dorididae phanerobranchiatae.
Sub-order IV. Pteropoda.— The Pteropoda are pelagic
animals in which the lateral portions of the foot are modified
into fins, which are innervated by the pedal ganglia. Their
systematic position has undergone recent revision. It has been
the custom to regard them as an Order of equivalent value to the
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XV PTEROPODA 435
other four, while some have held them to be a subdivision of
Cephalopoda. Modern authorities, chief among whom is Pel-
seneer, regard the Pteropoda not as a primitive, but as a derived
and recent group. They are “ Gasteropoda in which the adapta-
tion to pelagic life has so modified their external characters as
to give them an apparent symmetry.”
The principal point which relates the Pteropoda to the
Gasteropoda is the asymmetry of the visceral organs, intestine,
heart, kidney, and genital gland, which results from their
development on one side only of the body. ‘Their hermaphro-
ditism and the structure of their nervous system relate them to
the Euthyneura rather than to the Streptoneura. Resemblances
in the organs of circulation and generation approximate them to
the Opisthobranchiata rather than to the Pulmonata, while of
the two groups of the former, they tend to closer relationship
with the Tectibranchiata than with the Nudibranchiata. The
two sections of Pteropoda have been considered of distinct
origin, the Thecosomata being derived from the Bulloidea, the
Gymnosomata from the Aplysioidea.
Thus the Pteropoda are a group whose true relations are
masked by the special conditions of their existence, which have
tended towards the development of certain organs, the so-called
‘wines ” and the shell, which give them an apparent symmetry ;
this symmetry disappears on a closer investigation of the internal
organs. They are hermaphrodite; the genital gland has a single
efferent duct (except in some Cavolinia), a seminal groove lead-
ing to the copulatory organ, which in the Thecosomata is on the
right side of the head, in the Gymnosomata on the right side of
the foot. The genital system resembles that of the Opistho-
branchiata and of the “digonoporous ” Pulmonata.
Section 1. THECOSOMATA. — Shell or cartilaginoid test al-
ways present, fins united by an intermediate lobe, ctenidia as a
rule absent, replaced by secondary branchiae, no very distinct
head or eyes, one pair of tentacles; cerebral ganglia on the sides
of and under the oesophagus; radula with three rather large
teeth in a row, generally unicuspid, jaw in two pieces, stomach
with horny plates, anus generally on the left side.
The Thecosomata feed on Protozoa and the lower Algae ;
1 Tt appears more convenient to treat the whole group together, rather than
deal with the two sections separately. .
436 PTEROPODA — THECOSOMATA CHAP.
they have no proboscis, and the intestine is flexured. The fins
are always closely connected with the head, or what answers to
it. About 42 species are known, belonging to 8 genera.
Fam. 1. Limacinidae. — Fins very large, branchial chamber
dorsal, anus on right side; shell spiral, sinistral (ultra-dextral,
see p. 249), operculate. Genera: Jzmacina, shell helicoid,
deeply umbilicated (L. helicina swarms in Arctic seas and
furnishes food for many Cetacea); Peraclis, spire turreted,
aperture large, elongated, produced anteriorly, no umbilicus ;
operculum sinistral, in spite of the shell being ultra-dextral.
Fam. 2. Cavoliniidae.— Fins large, branchial chamber ventral,
Fic. 290.— Ilustrations of Pteropoda Thecosomata: A, Limacina australis Eyd.; B,
Cleodora cuspidata Bose. (shell only); C, Cuvierina columnelia Rang; D,
Creseis virgula Rang ; E, Clio balantium Rang ; J, f, fins ; 7, liver ; 0, ovary ;
sh, shell. (After Souleyet.)
shell a non-spiral cone, angular or round, very thin, embryonic
portion distinct, or formed of two separate plates.
In Cavolinia (= Hyalaea, Fig. 5B, p. 10) the shell consists of
two plates, the ventral being convex, with one to three sharp
spines at the posterior end, the dorsal flatter, without spines.
The aperture is broad, contracted dorso-ventrally. Two long
pointed prolongations of the mantle project from the lateral slits
of the shell, and probably serve to balance the bulky body when
swimming. Fins trilobed at the margin. Cleodora has only
rudimentary lateral prolongations, fins bilobed, shell triangular,
angles greatly produced, aperture very wide, dorsal side keeled.
In Cuvierina the shell is straight, sub-cylindrical, with a median
partition, sightly expanding towards the apex, which is truncated
in the adult. The principal sub-genera of Clio are Creseis, which
has an elongated sub-cylindrical shell, sometimes slightly curved,
XV PTEROPODA — GYMNOSOMATA 437
smooth or grooved; and Clio proper, in which the shell is long,
‘angular, with a dorsal rib, apex (=embryonic shell) rounded,
constricted. Styliola and Hyalocyliz also belong to this group.
Fam. 3. Cymbuliidae. — Vest (which is not homologous with
the shell of other Thecosomata) slipper-shaped, cartilaginoid,
simply a thickening of the mantle; embryo with a calcareous,
spiral, operculate shell. Genera: Cymbulia, Cymbuliopsis, Gleba.
Three other families, Hyalithidae, Pterothecidae, and Conu-
lariidae, from Palaeozoic strata, are generally added to the The-
cosomata. All are fossil only, and it is doubtful whether they
are really Molluscan. Pelseneer holds that no true fossil Ptero-
poda occur until the lower Tertiaries.
SECTION 2. GyMNOSOMATA.— Mantle and shell absent in
the adult, fins not connected by a lobe, no branchial chamber,
head well developed, with two pairs of tentacles, eyes on the
posterior pair; cerebral ganglia above the oesophagus; buccal
cavity provided with a pair of protrusible “ hook-sacs,” radula
generally with 4 to 12 hooked laterals, central tooth triangular,
jaw in one piece, composed of horny plates, no horny plates in
stomach, anus on the right side.
The Gymnosomata are carnivorous, feeding on Thecosomata
and other pelagic animals, being provided for this purpose with
a formidable buccal armature of hook-sacs and suckers. The
intestine, as usual in carnivorous groups, passes straight from
the stomach to the anus; the fins are not attached to the head,
but to the anterior part of the body. The larva has a straight
shell, which disappears in the adult. About 21 species are
known, belonging to 7 genera.
Fam. 1. Pneumodermatidae. — Animal fusiform, fins rather
small, head prominent, anterior part of buccal cavity protrusible,
with suckers on the ventral side, hook-sacs well marked;
branchia on right side, skin soft, pigmented. Genera: Dexvo-
branchaea, no posterior gill, hook-saes short; Spongiobranchaea,
posterior gill circular; Pnewmoderma, gill tetraradiate, hook-
sacs long.
Fam. 2. Olionopsidae. — Body barrel-shaped, proboscis three
times the length of the body, no buccal appendages; hook-sacs
short, no lateral gill, posterior gill tetraradiate, skin not pig-
mented. Clionopsis is the single genus.
Fam. 3. Notobranchaeidae. — Body ovate, buccal appendages
438 PTEROPODA — GYMNOSOMATA CHAP.
conical, no lateral gill, posterior gill with three radiating crests,
skin pigmented. Notobranchaea is the single genus.
Fam. 4. Clionidae. — Body long, angulated behind, proboscis
short, mouth with two or three pairs of appendages, no jaw, no
ills.
Clione limacina is so abundant in Arctic seas as at times to
colour the surface for miles. Each of the cephalic appendages
has about 60,000 minute pedicellated suckers.
Fie. 291.—A, An-
terior portion of
Pneumoderma;
B, Clione lima-
cina Phipps;
C, Halopsyche
Gaudichaudt
Soul.; 7, f;, finss
h.s, h.s, hook-
sacs; l.f, lobe of
the foot; s, 5s,
suckers; 0, pos-
terior genital
orifice: “t.2
tentacles. (After
Souleyet.)
Fam. 5. Halopsychidae.— Body ovate, thick, rounded behind,
no gill or proboscis, fins long, narrow, broadened at the ends,
epidermis sub-cartilaginoid.
Halopsyche (=Hurybia) has the power of withdrawing its
head completely into a sort of pocket, which is closed by an
anterior fold of the mantle. There are two long non-retractile
buccal appendages.
Order IV. Pulmonata
Gasteropoda with two pairs of tentacles, visceral loop euthy-
neurous, ganglia concentrated round the oesophagus ; breathing
air by a pallial cavity formed by the union of the front edge of
the mantle with the cervical region, sexes united, shell present
or absent, no operculum! (except in Amphibola).
Sub-order I. Basommatophora.— Eyes generally at the
base of the tentacles, which are not retractile, male and female
genital orifices separate, radula (p. 235) multiseriate, shell
always present, external. Fresh water or quasi-marine.
1 An operculum is said to exist in the young forms of Auricula and Parmacella.
xv PULMONATA — BASOMMATOPHORA 439
| AML Fee iie ees organ a acne sac
or true lung; shell spiral, conoidal, internal partitions usually
absorbed, aperture more or less
strongly toothed. Jurassic
Genera: Auricula, Carychium,
Scarabus, Alexia, Tralia, Pleco-
trema, Cassidula, Melampus,
Leuconia, Pedipes (Fig. 292).
Fam. 2. Otinidae.— Shell
auriform, spire very short.
Genera: Otina, Camptonyx. —
Recent only.
Fam. 38. Amphibolidae.— A
pulmonary lacie ely side of Fic. 292. — Examples of the Azriculidae:
neck, eyes almost pedunculate, A, Auricula Judae Lam., Borneo; B,
shell turbinate, rudely sculpt- Scarabus Lessoni Blainv., E. Indies;
C, Cassidula mustelina Desh., N. Zea-
ured, operculate.—Recent. land; D, Melampus castaneus Mihlt.,
Genus, Amphibola (Fig. 293) : = Pacific ; E, Pedipes quadridens Pir.,
; amalca.
subg. Ampullarina.
Fam. 4. Limnaeidae.— Pulmonary sac protected by an exter-
nal lobe; shell variable, fragile. Jurassic G.) Ancylinae,
shell more or less limpet-shaped. Genera: Ancylus, Gundlachia,
Latia. i.) Limnaeinae, shell spiral.: Genera: Limnaea, Amphi-
peplea, Erinna, Lantzia, Pompholyx, Choanomphalus (with
Carinifex). (iii.) Planorbinae, shell sinistral, spire flattened or
elevated. Genera: Planorbis, Isidora (= Bulinus).
Fam. 5. Physidae.— Mantle more or less reflected over the
shell (radula, Fig. 141c, p. 285); shell sinis-
tral, lustrous. Jurassic Genera: Physa,
Aplecta.
Fam. 6. Chilinidae. — Lobe of pulmonary
sac large, tentacles broad; shell ventricose,
rather solid; columella plicate. Miocene
Fie. 293.—Amphibola Single genus, Chilina.
avellana Chem.
Sub- order II. Stylommatophora. — Two
pairs of retractile tentacles (except in Janella), eyes at the tip
of the upper pair, male and female orifices united (except in
Vaginulidae and Onchidiidae), no distinct osphradium.
Fam. 1. Testacellidae. — Animal carnivorous, slug-like or
spirally coiled, no jaw (whence the name Agnatha, often given
440 PULMONATA — STYLOMMATOPHORA CHAP.
to this group), radula with usually few, large, sickle-shaped
teeth (p. 232), shell variable, rarely absent, usually external.
Cretaceous Principal genera: Chlamydephorus (shell a
simple plate, internal), may be simple flattered spaces or may
be broken up into definite channels, as
in Lingula (Fig. 815). It seems not
improbable that the body cavity fluid
is aerated through the thin inner layer
Fig. 315. — View of the inner side of the ane.
of a valve of Lingula anati- Running along the base of each arm
Jera (after Frangois),toshow are two canals, a small one at the base
the definite arrangement of :
the channels in the mantle: Of the tentacles, which we may term
a, position of mouth; 6,posi- the tentacular canal, and a larger
tion of anus. .
one, the canal of the lip. The former
sends a prolongation into each tentacle. The latter is, ac-
cording to Blochmann, a closed canal in Crania, Lingula, Rhyn-
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Xv THE HEART 473
chonella, and others; but according to Joubin,' it communicates
in Crania at one point with the tentacular canal. It is probably
originally a part of the body cavity. Blochmann? states in very
definite terms that in Crania neither the large canal nor the
small canal communicates with the general body cavity, but he
admits that in Lingula the small canal opens into that space.
The Circulatory System
The details of the discovery of the central circulatory organ
of Brachiopods form a curious and instructive chapter in the
history of modern morphological inquiry. Hancock, in his
monograph on the group, described and figured on the dorsal
surface of the alimentary canal a well-developed heart, which
had been previously noticed by Huxley, who first showed that
the organs which up to his time had been regarded as hearts
were in reality excretory organs. In connexion with this heart
Hancock described numerous arteries, distributed to various
parts of the body. The observers who have written upon the
anatomy of Brachiopods since Hancock’s time, in spite of the
fact that they had at their disposal such refined methods of
research as section cutting, which was quite unknown at the
time his monograph was written, have almost all failed to find
this circulatory system, and many of them have been tempted
to deny its existence. Blochmann,® however, in the year 1885
stated that he had found the heart, and had seen it pulsating in
several species of Brachiopoda which he had rapidly opened
whilst alive. Joubin has also described it in large specimens
of Waldheimia venosa, and recently Blochmann has published a
detailed account of his work on this subject. Both these authors
describe the heart as a vesicle with muscular walls, situated
dorsal to the alimentary canal. From this, according to Bloch-
mann, a vessel —the branchio-visceral of Hancock —runs forward
as a triangular split in the dorsal mesentery supporting the
alimentary canal. This vessel divides into two at the oeso-
phagus, and passing through some lacunae in the walls of this
1 «* Recherches sur |’ Anat. des Brachiopodes Inarticules,’’ Arch. Zool. Exp.
(2), Tome iv., 1886.
2 ‘* Untersuchungen tiber den Bau der Brachiopoden,”’’ Jena, 1892.
3 ‘* Vorliufige Mittheilungen iiber Brachiopoden,”’ Zool. Anz. Bd. viii. 1885.
474 RECENT BRACHIOPODA CHAP.
tube, opens into the tentacular canal, and consequently supplies
the tentacles with blood. These two canals which diverge
from the median artery are connected ventrally by a vessel which
runs below the oesophagus; the latter is therefore surrounded
by a vascular ring. Blochmann also describes two pairs of
vessels that were seen and figured by Hancock. A pair of
these pass over the gastro-parietal mesenteries and into the
dorsal mantle sinus, the second pair pass over the ileo-parietal
mesenteries and into the ventral mantle sinus; each of these four
arteries runs to one of the four generative glands, which, as is so
usually the case in the animal kingdom, have thus a specially
rich blood supply. _ If this description should prove to be correct,
the vascular system of Brachiopods shows a striking resemblance
to that of the closed vascular system of the unarmed Gephyrea,
except that the former group has specialised genital vessels.
The blood is colourless.
Joubin’s description of the vascular system of W. venosa differs
in some respects from that of Blochmann. He regards the heart
as collecting the lymph which it receives from numerous lacunar
spaces in the walls of the alimentary canal, and distributing it
through various vessels, which in the main correspond with those
of Blochmann, and which run both to the “arms” and to the
generative glands. The latter vessels, however, open freely
into the body cavity, and the fluid which is forced out from
their openings freely bathes the organs found in the body
cavity. Whichever of these accounts should prove to be more
closely in accordance with the facts, there is little doubt that in
addition to the true blood there is a corpusculated fluid in the
body cavity which is to some extent kept in motion by the
ciliated cells that lne its walls.
The Excretory Organs
The excretory organs (kidneys) which were at one time
regarded by Cuvier and Owen as hearts, are typical nephridia —
that is to say, they are tubes with glandular excretory walls
which open at one end by a wide but flattened funnel-shaped
opening into the body cavity, and at the other end by a circular
pore to the exterior (Fig. 314). In Rhynchonella, where
there are two pairs of these tubes, —the only evidence that the
group presents of any metameric repetition of parts,—the inner
XVII TELE eSrAIK 475
ends of the anterior pair are supported by the gastro-parietal
mesenteries, and those of the posterior pair by the ileo-parietal
mesenteries. In all other Brachiopods the posterior pair alone
exists. The external opening of these nephridia is near the
base of the anus; in Cistella it is at the bottom of a brood-pouch
formed by the tucking in of the body wall in this neighbour-
hood, and in this brood-pouch the eggs develop until the larval
stage is reached.
The walls of these nephridia are lined by ciliated cells,
amongst which are some excretory cells, in which numerous
brown and yellow concretions are to be seen; these are probably
the nitrogenous excreta of the animal, and pass out of the body,
being washed away by the stream of water which is constantly
passing between the shells.
As in so many other animals, the nephridia act as genital
ducts, and through them the ova and spermatozoa, which break
off from the genital glands and fall into the body cavity, find
their way to the outer world.
The Stalk and Muscles
The body cavity of a Brachiopod is traversed by several pairs
of muscles, which are very constant in position, and whose con-
traction serves to open and close the shell, to move the animal
upon its stalk, and to govern the movements of the arms.
The stalk is absent in Crania, and the members of this
genus are attached to: the rocks on which they are found by the
whole surface of their ventral valve. In Lingula (Fig. 315)
the stalk is long and hollow, containing what is probably. a
portion of the body cavity, surrounded by muscular walls.
Lingula is not a fixed form, but lives half-buried in the sand
of the sea-shore (Fig. 821). Discina, the other member of
the Ecardines, has a peduncle which pierces the ventral valve
and fixes the animal to its support. Amongst the Testicardines,
Thecidium is also fixed to its supports by the surface of its
ventral valve; the other genera, however, are provided with
stalks, which, being the means of the fixation of the animals,
become at the same time the fixed points upon which their
very limited movements can be effected. The stalk protrudes
through the notch or aperture at the posterior end of the ventral
476 RECENT BRACHIOPODA CHAP.
valve, and it probably belongs to the ventral side of the body.
It is in (stella, and doubtless in other genera, in close organic
connexion with both valves, and it seems to consist of an un-
usually large development of the supporting tissue which occurs
so frequently in the body of Brachiopods. The surface of the
peduncle is produced into several irregularities and projections
which fit into any depressions of the rock upon which the
animal is fixed.
In Cistella there are four pairs of muscles, two connected
with opening and closing the shell, and two with the movement
of the body upon the stalk (Fig. 314). The most considerable
of these muscles are the two occlusors, which have their origin,
one on each side of the middle line of the dorsal valve, and their
insertion by means of a tendon into the ventral valve. In the
species in question each of these muscles arises by a double
head, the two muscles thus formed probably representing the
anterior and posterior occlusors of other forms. The contraction
of these muscles undoubtedly serves to close the shell, which
is opened by a small pair of divaricators arising from the
ventral valve, and inserted into a portion of the dorsal shell
which is posterior to the axis of the hinge. Contraction of
these muscles would thus serve to approximate the posterior
edges of the valves and divaricate the anterior edges and thus
to open the shell.
The adjustors are four in number, a ventral pair running
from the ventral valve to be inserted into the stalk, and a corre-
sponding dorsal pair from the dorsal valve. The simultaneous
contraction of either pair would tend to raise the valve, whilst
the alternate contraction of the muscles of each side would tend
to rotate the shell upon the peduncle. The muscles of Wald-
heimia flavescens are shown in Fig. 329, and described briefly
on p. 502.
The muscles of the Ecardines differ from those of the Tes-
ticardines inasmuch as they do not terminate in a tendon,
but the muscle fibres run straight from shell to shell. They
are also more numerous. In Crania there is an anterior and
a posterior pair of occlusor muscles, and two pairs of oblique
muscles, which seem when they contract together to move the
dorsal shell forwards, or when they contract alternately to
slightly rotate it. In this genus there are also a pair of pro-
XVII THE MUSCULAR SYSTEM 477
tractors and a pair of retractors, and two levators of the arms,
whose function is to draw forward or retract the arms, and an
unpaired median or levator ani muscle. In addition to these
bundles of muscles there are certain muscles in the body wall,
and it seems probable that by their contraction, when the
adductors are relaxed, the body may become somewhat thicker
and the valves of the shells will slightly open.
In Lingula (Fig. 322) the muscular system is more com-
Fic. 316. — A semi-diagrammatic
figure of the muscular system
of Crania (after Blochmann):
a, anterior occlusor; b, poste-
rior occlusor; ¢c, superior ob-
lique; d, inferior oblique; e,
retractor of the arms; /, ele-
vator of the arms; g, protractor
of the arms; /, unpaired me-
dian muscle. The dorsal valve
is uppermost.
plicated; in addition to the anterior (=anterior laterals) and
posterior (=centrals) pairs of occlusors, there is a single divari-
cator (= umbonal), whose contractions in conjunction with those
of certain muscles in the body wall press forward the fluid in
the body cavity, and thus force the valves of the shell apart;
and there are three pairs of adjustor muscles. ‘These latter are
called respectively the central (= middle laterals), external
(= external laterals), and posterior (= transmedians ) adjustors,
whose action adjusts the shells when all contract together, and
brings about a certain sliding movement of the shells on one
another when they act independently of each other.!
1 Hancock’s nomenclature is here used. The corresponding names used by
King and Brooks are placed in brackets. Their nomenclature is used by many
palaeontologists, and is adopted in Fig. 322.
478 RECENT BRACHIOPODA CHAP.
The Nervous System
The nervous system of Brachiopods is not very clearly
understood, and there are considerable discrepancies in the
accounts of the various investigators, even when they are
dealing with the same species. So much, however, seems certain,
that there is a nervous ring surrounding the oesophagus, that
this ring is enlarged dorsally, or, in other words, near the base
of the lip, into a small and inconspicuous dorsal ganglion, and
again ventrally or just behind the base of the tentacles into a
ventral or sub-oesophageal ganglion. The latter is, contrary to
what is usual in Invertebrates, of much larger size than the
supra-oesophageal ganglion, but like the last named, it has re-
tained its primitive connexion with the ectoderm or outermost |
layer of the skin. Both ganglia give off a nerve on each side
which runs to the arms and along the base of the tentacles and
lips. The sub-oesophageal ganglion also gives off nerves which
supply the dorsal and ventral folds of the mantle, the muscles,
and other parts.
The modified epithelium in connexion with the ganglia may
possibly have some olfactory or tactile function, but beyond this
the Brachiopoda would appear to be devoid of eyes, ears, or any
other kind of sense organs,—a condition of things doubtless
correlated with their sessile habits, and with the presence of a
bivalved shell which leaves no part of their body exposed.
The Reproductive System
The majority of Brachiopods are bisexual, and many autho-
rities regard the separation of sex as characteristic of the group ;
on the other hand, Lingula pyramidata is stated to be herma-
phrodite, and it is not impossible that other species are in the
same condition.
The generative organs are of the typical sort, that is, they
are formed from modified mesoblastic cells lining the body
cavity. These cells are heaped up, usually in four places, and
form the four ovaries or testes as the case may be (Fig. 314).
The generative glands usually le partly in the general body
cavity and partly in the dorsal and ventral mantle folds, two on
each side of the body. Along the axis of the heaped-up cells
XVII DEVELOPM ENT 479
runs a blood-vessel, which doubtless serves to nourish the gland,
the outer surface of which is bathed in the perivisceral fluid.
Every gradation can be found between the ripe generative cell
and the ordinary cell lining the body cavity. When the ova
and spermatozoa are ripe they fall off from the ovary and testis
respectively into the body cavity, thence they are conveyed to
the exterior through the nephridia. The ova in certain genera,
such as Argiope, Cistella, and Thecidium, develop in brood-
pouches which are either lateral or median involutions of the
body wall in the neighbourhood of the external opening of
the nephridia; they are probably fertilised there by spermatozoa
carried from other individuals in the stream of water which
flows into the shell. In other species the ova are thrown out
into the open sea, and their chances of meeting with a sperma-
tozoon is much increased by the gregarious habits of their sessile
parents, for as a rule considerable numbers of a given species
are found in the same locality.
The Embryology
We owe what little we know of the Embryology of the group
chiefly to Kowalevsky,! Lacaze-Duthiers,2? and Morse.? The
Russian naturalist worked on Cistella (Argiope) neapolitana, the
French on Thecidium, and the American chiefly on Terebratulina.
Although this is not known with any certainty, it seems
probable that the eggs of Brachiopods are fertilised after they
have been laid, and not whilst in the body of the mother. The
spermatozoa are doubtless cast out into the sea by the male,
and carried to the female by the currents set up by the cilia
clothing the tentacles.
In Thecidium, Cistella, and Argiope the first stages of devel-
opment, up to the completion of the larva, take place in brood-
pouches; in Terebratulina the eggs pass out of the shell of the
mother and hang in spermaceti-white clusters from her setae
and on surrounding objects. In the course of a few hours they
become ciliated and swim about freely. The brood-pouch in
1 Development of the Brachiopoda, 1875 (Russian),
2 «¢ Histoire de la Thécidie,’’? Ann. d. Sci. Nat., Sér. 4, vol. xv., 1861.
3 *¢On the Early Stages of Terebratulina septentrionalis,’’? Mem. Boston Soc.
Nat. Hist., vol. ii., 1869. ‘*On the Development of Terebratulina,’’ Zbid. vol.
lila, L&do:
480 RECENT BRACHIOPODA CHAP.
Thecidiwm is median, in the convex lower shell, in Cistella it is
paired, and arises by the pushing in of the lateral walls of the
body in the region just behind the horse-shoe-shaped tentacular
arms; the renal ducts, which also serve as oviducts, open into
these lateral recesses.
In the female Thecidiuwm (Fig. 317) the two median tentacles
which lie just behind the mouth are enlarged and their ends
somewhat swollen; they are bent back into the brood-pouch,
and to them the numerous larvae are attached by a short fila-
ment inserted into the second of the four segments into which
the larva is divided. In (%istella a similar filament attaches the
larvae to the walls of the brood-sac ; thus they are secured from
Fic. 317. — Brood-pouch of Thecidium
mediterraneum. (After Lacaze-
Duthiers.) Part of the wall of the
pouch has been removed to show
the clusters of larvae.
1. Mouth, overhung by lip.
2. One of the two median ten-
tacles which are enlarged and
modified to bear the larvae.
3. Wall of brood-pouch into
which the median tentacles are
folded.
4. Larva attached to the swollen
end of the tentacles.
being washed away by the currents constantly flowing through
the mantle cavity of the mother.
In Cistella the larva consists at first of two segments, but
the anterior one divides into two, so that in the free swimming
larva we find three segments, the hindermost somewhat longer
and narrower than the others and destined to form the stalk.
About the time of the appearance of the second segment four
red eye-spots arise in the anterior segment, which tends to be-
come constricted off from the others, and may now be termed
the head. It gradually becomes somewhat umbrella-shaped,
develops cilia all over its surface and a special ring of large cilia
round its edge.
In the meantime the second or mantle segment has grown
down and enveloped the stalk, and four bundles of setae have
XVII HABITS OF LARVAE 481
arisen from its edge. In this stage the larva leaves its mother’s
shell and swims out into the world of water to look for a suit-
able place on which to settle down. This is the only stage in the
life history of a Brachiopod when the animal is locomotor, and can
serve to spread its species. The extreme minuteness of the larva
and the short time it spends in this motile condition probably
accounts for the fact that Brachicpods are extremely localised.
Where they do occur they are found in great numbers, rocks
being often almost covered with them, but they are not found over
large areas. When viewed under a microscope the larvae seem
Y
Tir,
|
I
mT ai TANK A
fl M\\\ ANY
| Wy
Fic. 318.— Young larva of
Cistella neapolitana,
showing three _ seg-
ments, two eye-spots, Fig. 319.— Full-grown larva of Cis-
and two bundles of tella neapolitana, with umbrella-
setae. (After Kowa- shaped head, ciliated. (After
levsky.) Kowalevsky.)
to be moving with surprising rapidity, but judging from the
analogy of other forms, it seems doubtful if they swim a yard in
an hour.
Frequently the larva stands on its head for some time, as if
investigating the nature of the rocks on which it may settle; it
is extremely contractile, turning its head from time to time,
and seldom retaining the same outline for any length of time; the
setae are protruded, and at times stick out in every direction ;
they are possibly defensive in function. When fully stretched
out the larva is about } mm. long, but it frequently shortens its
VOL. III 21
482 RECENT BRACHIOPODA CHAP.
body to two-thirds of this length. The larvae are of a pinkish
red colour, with eye-spots of ruby red. Their colour renders
them difficult to discern when they are swimming over the red
coralline rocks upon which they frequently settle. After swim-
ming about for a few hours the larva fixes itself finally,
apparently adhering by some secretion produced by the stalk
seoment. ‘The folds of the second or body segment then turn
forward over the head, and now form the ventral and dorsal
mantle folds; these at once begin to secrete the shell on their
60 564
aeQq qoute
Fic. 520. — Stages in the development of the larva of Terebratulina septentrionalis.
(After Morse.) The youngest larva has two segments, a third then appears, the
larva then fixes itself, and the second segment folds over the first and develops
bristles round its edge.
outer surfaces. The head with its eye-spots must be to some
extent absorbed, but what goes on within the mantle is not
accurately known. The setae drop off and the tentacular arms
begin to appear as a thickening on the dorsal lobe of the mantle.
They are at first circular in outline. The various changes which
the larva passes through are well illustrated by Morse for Tere-
bratulina, which spawns at Eastport, Me., from April till August.
The different stages are represented in outline in Fig. 320, taken
from his paper. |
Habits
There is little to be said about the habits and natural history
of the Brachiopoda. When once the larva has settled down, the
animal never moves from the spot selected; occasionally it may
rotate slightly from side to side on its stalk, and from time to
time it opens its shell. As so frequently is the case with sessile
animals, the sense organs are reduced to a minimum, the eyes
of the larva disappear, and the only communication which the
XVII
animal has with the world around it is
by means of the currents set up by the
cilia on the tentacles.
In spite of the absence of any definite
eyes, Thecidium, according to Lacaze-
Duthiers, is sensitive to light ; he noticed
for instance that, when his shadow fell
across a number of these animals he was
watching in a vessel, their shells, which
had been previously gaping, shut up at
once.
In Cistella the tentacles can be pro-
truded from the open shell, and in Rhyn-
chonella the spirally-coiled arms can be
unrolled and extruded from the shell, but
this does not seem to have been observed
in other genera, with the possible ex-
ception of Lingula. The food of these
animals consists of minute fragments
of animal and vegetable matter, a very
large proportion of it being diatoms and
other small algae.
Lingula differs markedly from the
other members of the group, inasmuch
as it is not firmly fixed to a rock or
some such body by a stalk or by one of
its valves, but lives in a tube in the
sand. Some recent observations of
Mons. P. Frangois! on living specimens
of Lingula anatifera which he found
living in great numbers on the sea-
shore at Nouméa in New Caledonia
may be mentioned. The presence of
the animal is shown by a number of
elongated trilobed orifices which lead
into the tube in which the Lingula lives.
The animals, like most other Brachi-
opods, live well in captivity, and he was
able to watch their habits in the aquaria
HABITS OF LINGULA
Fig. 521. — Figures illustrating
the tubes in which Lingula
anatifera lives. The upper
figure is a view of the tri-
lobed opening of the tube.
The lower figure shows the
tube in the sand laid open
and the animal exposed.
The dotted line indicates the
position of the body when
retracted. The darker por-
tion is the tube of sand ag-
glutinated by the secretion of
the stalk. (After Francois.)
1“‘Choses de Nouméa,’’ Arch. d. Zool. exp. et gen., 2nd ser., vol. ix., 1891.
484 RECENT BRACHIOPODA CHAP.
of his laboratory. The Lingula place themselves vertically; the
anterior end of the body just reaches the level of the sand;
the three lobes into which the orifice of the tube is divided cor-
responding with the three brushes of setae which project from
the anterior rim of the mantles. These setae are described by
Morse as projecting in the form of three funnels; currents of
water are seen continually passing in at the side orifices and out
through the central. The tube consists of two portions: an
upper part, which is flattened to correspond with the flat shape
of the body, and a lower part, in which the stalk hes. The
upper part is lined with a layer of mucus, but the sand is not
glued together to form adefinite tube. The lower part of the stalk,
or the whole when the animal is contracted, is lodged in a
definite tube composed of grains of sand agglutinated by mucus,
probably secreted from the walls of the stalk. At the least sign
of danger the stalk is contracted violently, and the body is
withdrawn to the bottom of the upper portion of the tube. The
rapid retreat of the animal is followed by the collapse of the
sand at the mouth of the tube, and all trace of the presence of
the Lingula is lost.
The shells of this species are frequently rotated through a
small angle upon one another, a movement which is prevented
in the Testicardines by the hinge. In very young transparent
specimens Frangois was able to observe the movements of the
fluid in the system of tubules which penetrate the mantle; these
tubules are figured by him, and Fig. 815 is taken from his
illustration.
Davidson in his Monograph on the British Fossil Brachi-
opoda states that the largest “recent Brachiopod which has
come under my notice is a specimen of Waldheimia venosa
Solander, measuring 38 inches 2 lines in length, by 2 inches in
breadth, and 1 inch 11 lines in depth.” It was found in the
outer harbour of Fort William, Falkland Islands, in 1843. A
specimen of Terebratula grandis from the Tertiary deposits, how-
ever, exceeds this in all its dimensions. Its length was 44
inches, its breadth 3 inches 2 lines, and its depth 2 inches 2
lines.
Distribution in Space
Brachiopods are very localised; they live in but few places,
XVII VERTICAL DISTRIBUTION 485
but when they are found they usually occur in great numbers.
During the cruise of the Challenger, dredging was conducted at
361 stations; at only 38 or 89 of these were Brachiopoda brought
up. Mr. Cuming, quoted by Davidson, records that after a great
storm in the year 1836, he collected as many as 20 bushels of
Lingula anatifera on the sea-shore at Manilla, where, he relates,
they are used as an article of food. It has been suggested above
that their abundance in certain localities is due to their limited
powers of locomotion, which are effective but for a few hours,
the larva being, moreover, so minute that unless borne by a
current it could not travel far from its parent. When once
settled down it has little to fear from the attacks of other
animals. The size of its shell relative to its body would deter
most animals from regarding it as a desirable article of food,
and as far as is known at present the Brachiopoda suffer but
little from internal parasites, the only case I know being a
minute parasitic Copepod belonging to a new and as yet unnamed
genus which I found within the mantle cavity of Cistella (Argi-
ope) neapolitana in Naples. Their slight value as an article of
diet has doubtless helped to preserve them through the long
periods of geological time, through which they have existed
apparently unchanged.
Two of the recent genera of the family Lingulidae, Lingula
and Glottidia, are usually found between tide-marks or in shallow
water not exceeding 17 fathoms. Discina is also found about
the low-tide level, but one species at any rate, Discinisea atlan-
tica, has been dredged, according to Davidson, “at depths rang-
ing from 690 to nearly 2425 fathoms.” Their larvae frequently
settle on the shells of their parents, and thus numbers of over-
lapping shells are found clustered together. Crania is usually
dredged from moderate depths down to 808 fathoms, adhering
to rocks, lumps of coral, stones, and shells.
Of the Testicardines, Terebratula Wyvillet has probably been
found at the greatest depth, 7z.e. 2900 fathoms, in the North
Pacific. It is interesting to note that its shell is glassy and
extremely thin. The Brachiopoda are, however, as a rule,
found in shallower water; they abound up to a depth of 500 or
600 fathoms, after which they rapidly diminish with increasing
depth. About one-half the named species occur at a depth of
less than 100 fathoms.
486 RECENT BRACHIOPODA CHAP.
The vertical range of depth of certain species is great; Tere-
bratula vitrea is recorded from 5 to 1456 fathoms, 7. Wyvillez
from 1035 to 2900 fathoms. This is to some extent expli-
cable since, after a certain depth has been reached, many of
the external conditions, such as absence of temperature and
light, must remain constant even to the greatest depths of the
ocean. i
The area of the ocean explored by dredging forms such an
infinitesimal fraction of the whole, that it seems superfluous to
consider the horizontal distribution of Brachiopods. A few
facts may, however, be mentioned. Certain species, as Terebra-
tula vitrea, T. caput serpentis, Waldheimia cranium, Megerlia
truncata, and Discinisca atlantica, have a very wide if not cos-
mopolitan distribution. The second of the above named extends
as far north as Spitzbergen, and as far south as Kerguelen
Island. Many species are, on the other hand, very localised,
and have hitherto only been found in one place. A very con-
siderable number of these have been dredged off Japan and
Korea, and this region may be to some extent regarded as the
headquarters of the group.
The following species have been obtained within the limits
of the British Area, as defined by Canon Norman, who has been
good enough to revise the list, which is founded on that drawn
up by Davidson in his Challenger Report. Their range of
bathymetric distribution is given in the column on the left.
Depth in
Fathoms
0 to 1180. Terebratulina caput serpentis Lin. Oban, and off Cumbrae Islands,
Loch Torridon, Scotland, off
Belfast
8to 25. Terebratula (Gwynia) capsula Jeff. Belfast Bay, E. and S. coast of
Ireland, Plymouth, Weymouth,
and Guernsey
5 to 690. Waldheimia cranium Miiller . . North British seas. Off Shet-
land
75 to 725. Waldheimia septigera Lovén . . North British seas. Off Shet-
land
20 to 600. Terebratella spitzbergenensis Dav. N.N.W. of Unst, Shetland
18 to 364. Argiope decollata Chemnitz . . Two miles east of Guernsey
20to 46. Cistella cistellulaS. Wood . . Shetland, near Weymouth, S.
coast of England
650 to 1750. Atretia gnomon Jeff. . . . . W. of Donegal Bay in 1443
faths. Between Ireland and
Rockall, in 13850 faths.
XVII CLASSIFICATION AND AFFINITIES 487
Depth in
Fathoms
10 to 690. Rhynchonella psittacea Gmelin . Shetland and near Dogger Bank.
This species is possibly fossil
as well as recent
3 to 808. Crania anomala Miiller . . . Loch Fyne, North of Scotland
690 to 2425. Discinisca atlantica King. . . W.of Donegal Bay in 1366 faths.,
W. of Ireland in 1240 faths.,
off Dingwall Bay
Classification
The table of classification here appended is that suggested
by Mr. Davidson in his Monograph on the Recent Brachiopoda.
I. TESTICARDINES
Family
A. TEREBRATULIDAE. Thisincludes the majority of genera and of species,
the latter, without counting uncertain species,
amounting to sixty-eight. Examples: Terebra-
tula, Terebratella, Terebratulina, Waldheimia,
Megerlia, Argiope, Cistella.
B. THECIDIIDAE. This family contains one genus, Thecidium, with
two species.
C. RHYNCHONELLIDAE. This family is made up of eight species, six of
which belong to the genus Rhynchonella, and two
to Atretia.
Il. ECARDINES
D. CRANIIDAE. This family comprises the four species of Crania.
KE. DiIscrniDAeE. This family contains one species of Discina and
six of Discinisca.
F. LINGULIDAE. This family consists of eight species of Lingula
and three of Glottidia.
It is impossible to come to any satisfactory conclusion as to
the position of the group Brachiopoda with relation to the rest
of the animal kingdom. They have, in accordance with the
views of various investigators, been placed in close connexion
with many of the large groups into which the Invertebrates are
spht up. The Mollusca, the Tunicata, the Polyzoa, the Chaeto-
poda, the Gephyrea, and of recent times such isolated forms as
Phoronis and Sagitta, have all in turn had their claims advanced
of relationship to this most ancient group. As far as Iam ina
position to judge, their affinities seem to be perhaps more closely
with the Gephyrea and with Phoronis than with any of the other
488 RECENT BRACHIOPODA CHAP. XVII
claimants; but I think even these are too remote to justify any
system of classification which would bring them together under
a common name. Investigation into the details of the embry-
ology of the group, more especially into that of the Ecardines,
might throw some light on this subject, and it is much to be
desired that this should be undertaken without delay. That
the group is a most ancient one, extending from the oldest
geological formations, we know, that the existing members of
it have changed but little during the vast lapse of time since
their earliest fossil ancestors flourished, we believe; but we are
in almost total ignorance of the origin or affinities of the group,
and we can hardly hope for any light on the subject except
through embryological research.
BRACHIOPODA
PAGE If
PALAEONTOLOGY OF THE BRACHIOPODA
BY
F. R. COWPER REED, B.A., F.G.S.
Trinity College, Cambridge
CHAPTER XVIII
PALAEONTOLOGY OF THE BRACHIOPODA
INTRODUCTION — DIVISION I. ECARDINES — EXTERNAL CHAR-
ACTERS — INTERNAL CHARACTERS — DIVISION II. TESTI-
CARDINES — EXTERNAL CHARACTERS — INTERNAL CHAR-
ACTERS — SYNOPSIS OF FAMILIES — STRATIGRAPHICAL
DISTRIBUTION — PHYLOGENY AND ONTOGENY
Introduction
T' wide distribution and vast abundance of the Brachiopoda
throughout the whole series of geological formations make this
group of especial importance to the student of the past history
of the earth; and the zoologist must always regard the fossil
forms with peculiar interest, because they not only largely out-
number the living representatives, but comprise numerous extinct
genera, and even families, exhibiting types of structure and char-
acters entirely absent in the modern members of the group.
It is a most fortunate circumstance that the excellent state of
preservation in which we frequently find them, and the immense
amount of material at our disposal, enable us to determine with
accuracy and certainty the internal characters of the shells in
the great majority of cases. But it is only since the beginning of
the present century that our knowledge of the anatomy of the soft
parts of the living animal has rendered any tracing of homologies
possible. In the case of features in fossil extinct types the inter-
pretation must be to some extent doubtful. Barrande, Clarke,
Davidson, Hall, King, Oehlert, Waagen, de Verneuil, and a host
of other workers have contributed to the information which we
now possess; and their works must be consulted for details of the
subject!
1J. Barrande, Syst. Silur. Bohéme, vol. v., 1879. Hall and Clarke, Introd.
Palaeozoic. Brach. (Palaeont. of New York, 1892-1894). Davidson, Monogr.
49g!
492 FOSSIL BRACHIOPODA CHAP.
Since all Brachiopods are inhabitants of the sea, the geologist
at once recognises as a marine deposit any bed which contains
their remains. Under favourable conditions they swarmed in the
seas of Palaeozoic and Mesozoic times. Beds of limestone are fre-
quently almost entirely composed of their shells, as, for instance,
some of the Devonian limestones of Bohemia. Often they give
the facies to the fauna and outnumber in species and individuals
all the other organisms of the period. The Ungulite Sandstone
(Cambrian) of Russia and the Productus Limestone of the Salt
Range in India of Carboniferous and Permian age are well-
known examples.
Many species seem to have been gregarious in habit; thus
Productus giganteus of the Carboniferous Limestone may gen-
erally be found in crowded masses, as in some localities in
Yorkshire.
The fact that certain species of Brachiopods characterise
definite stratigraphical horizons or “zones” gives them occasion-
ally an importance equal to that of Graptolites; for instance, the
Ecardinate species Trematis corona marks a set of beds in the
Ordovician, and the isolated Stringocephalus Burtini is restricted
to the upper part of the Middle Devonian, giving to the lime-
stone on that horizon its distinctive name. It is noteworthy also
how certain species affect a sandy and others a calcareous sea-
bottom, so that beds of the same age show differences in their
Brachiopod fauna owing to a dissimilar lithological composition.
While few of the recent Brachiopods reach a large size, some
of the extinct species measure several inches in breadth, but the
great Productus giganteus attained the width of even a foot.
The bright colours of the shells of the living animals are
not generally preserved amongst the fossil species from the older
rocks; yet in a Carboniferous TYerebratula we can even now
detect the purple bands in some specimens, and a Cretaceous
Rhynchonella similarly exhibits its original colour.
The Brachiopoda are evidently a group in its decline, as the
geological record shows; but they date back from the earliest
known fossiliferous rocks, in which the Ecardinate division
is alone represented. As we ascend through the stratigraphical
series the number and variety of genera and species belonging to
Brit. Foss. Brach. (Palaeont. Soc., 1851-1884). Waagen, Salt Range Fossils
(Mem. Geol. Surv. India, 1879-1885).
XVIII ECARDINES: EXTERNAL CHARACTERS 493
both divisions rapidly increase until in the united Ordovician
and Silurian there are nearly 2000 species and about 70 genera.
From this point of maximum development down to the present
day there is a gradual decrease in numbers.
According to Davidson, at least 17 Upper Tertiary species
are still living on our sea-bottoms; and many recent Mediterra-
nean forms occur in the Pliocene rocks of the islands and shores
of that sea, and in the Crags of East Anglia.
A brief review of the chief characteristics of fossil Brachio-
poda is given below. Those genera which have the greatest
zoological or geological importance can alone be noticed owing
to the exigencies of space.
I. ECARDINES
External Characters
A considerable diversity of external form is met with even in
this division, from the hmpet-like Discina to the flattened tongue-
shaped Lingula. ‘The valves have most commonly a smooth ex-
ternal surface with delicate growth-lines; but sometimes pittings
(Trematis) or radiating ribs (Crania) are present, and in a few
forms the shell is furnished with spines (Stphonotreta), which
perhaps serve to anchor it in the soft mud of the sea-bottom.
The usual mode of fixation was by means of the pedicle (= pe-
duncle or stalk), which either (1) passed out simply between the
posterior gaping portion of the valves (Lingula), or (2) lay in
a slit in the ventral valve (Lingulella), or (8) pierced the sub-
stance of the latter valve by a definite foramen (Discina). The
first-mentioned condition of the pedicle seems the most primitive.
Rarely the pedicle was absent, and the shell was attached by the
whole surface of the ventral valve (Crania, p. 467).
The two valves in the fossil Ecardines were held together by
muscular action, though in some families ( Zrimerellidae) we see
traces of articulating processes. The “hinge line,” or line along
which the valves worked as on a hinge, is in most forms more or
less curved. A “hinge area” (7.e. that portion of the shell gen-
erally smoother than other parts of the valves, more or less tri-
angular in form, and lying between the beaks on one or both
sides of the hinge line), is usually absent in the Ecardines.
494 FOSSIL BRACHIOPODA CHAP.
Internal Characters
Owing to the rarity of well-preserved interiors of valves in
this division, our knowledge of their internal characters is still
far from satisfactory. The arrangement of the muscular impres-
sions varies greatly amongst extinct genera, but we are often able
to interpret them with a considerable amount of certainty by a
study of the scars and the muscles of the well-known recent
LTingula (Fig. 322). The extreme specialisation of the muscles
in many of the earliest genera (e.g. Lingula) is remarkable, and
points to a long but so far undiscovered ancestry in pre-Cambrian
times. In fossil species of Crania and Lingula the muscle-scars
correspond closely with those
in the living representatives
of these genera. In the most
highly specialised family of
the Ecardines—the Trimerel-
lidae—we meet with features
of peculiar interest.2. The
muscle-scars in this family
(Fig. 323, A, B) are most
remarkable for the develop-
ment of the so-called ‘“cres-
cent,” (q.7.s.) which skirts
Fig. 322. — Muscle-scars of Lingula anatina. the posterior margin of both
Inner surface of A, Pedicle-valve or ven- valves aS a sub-cardinal im-
tral valve. B, Brachial or dorsal valve; ig ek . °
p.s, parietal scar; uw, umbonal muscle; f, (Uses Ul It is believed to
transmedians; c,centrals; a.m.e, laterals be the trace of a strong post-
(a, anteriors; m, middles; e, externals). parietal muscular wall, anal-
ogous in position to that of Zingula. The three pairs of “lat-
eral” muscle-scars in the latter genus seem to be represented
by the “terminal” (s) and “lateral” (7) scars on the crescent
1 The results of the investigations of King (Ann. Mag. Nat. Hist., 4th ser.,
vol. xii., 1873) and of Brooks (Chesapeake Zool. Laboratory, Scientific Results,
p. 35, 1879), and the simple nomenclature of these authors are here followed in
preference to those of others, owing to the difference of opinion amongst anato-
mists of the functions and homologies of the muscles. The lateral muscles enable
the valves to move backwards and forwards on each other; the centrals close the
shell; the umbonals open it; and the transmedians allow a sliding sideways
movement of one valve across the other (see also p. 477).
* Davidson and King, Quart. Jour. Geol. Soc., xxx. (1874), p. 124.
XVIII ECARDINES: INTERNAL CHARACTERS 495
of the Zrimerellidae. A pair of “transverse” scars (¢) occurs
in each valve between the “terminals” and the antero-lateral
edge of the “platform” (7). “Cardinal” (v), “sub-cardinal”
(w), and “umbo-lateral” (2) scars also occur. The median
impression which covers the ‘“ platform” (7) consists of a
central, lateral, and usually an anterior pair of scars; and the
impressions of the genital organs, according to Davidson and
King, lie medianly posterior to the “platform.” The “platform”
Fic. 323. — Trimerella. (After Davidson and King.) A, Inner surface of pedicle-valve
or ventral valve: a, pseudo-deltidium; 6, deltidial slope; c, deltidial ridges; d,
areal borders; e, cardinal callosities; f, cardinal facet; g, lozenge; 7, umbonal
chambers separated by cardinal buttress; j, platform; &, platform vaults; /, median
plate; m, median scars; n, anterior scars; 0, lateral scars; p, post-median scars ;
q, crown crescent; 7, side or lateral crescent; s, end or terminal crescent; ¢, trans-
verse scars; u, archlet (vascular sinuses); w, sub-cardinal scars; x, umbo-lateral
sears. B, Brachial or dorsal valve: e, cardinal sockets; j, platform; k, platform
vaults; 7, median plate; m, median scars; 7, anterior scars; g, crown crescent ;
r, side or lateral crescent; s, end or terminal crescent; ¢, transverse scars;
u, archlet (vascular sinuses); v, cardinal scars; w, sub-cardinal scars.
itself is a more or less conspicuous central calcareous elevated
area occurring in each valve, but most developed in the dorsal ;
in some cases it is double-chambered with tubular cavities
(“ platform vaults,” Fig. 323, A, B, £), in others it is more or
less solid. It appears to have originated through a posterior
shifting of the central muscular bands, that they might be inserted
behind the liver; at the same time a deposition of shelly material,
to form fulcra to work the heavy valves, took place at these
points. The tunnelling-out of the platform was probably due
496 FOSSIL BRACHIOPODA CHAP,
to the continual pressure of the lobes of the liver. The division
of the umbonal cavity into definite chambers in Monomerella,
and to a less extent in other members of this family, appears,
according to Davidson and King, to have been caused by pressure
of the ovarian lobes.
In connexion with the foregoing remarks on the development
of the “ platform,” it may be mentioned that the paths along
which the muscle-bands move, as the shell of Brachiopods in-
creases in size, are marked by elongated scars, and often by
shelly deposits; and when the members of a muscle-pair come
into juxtaposition these shelly deposits (which act as fulcra for
the muscles) combine, and by the growth of the shell form a
septum, as in the case of the median septum of Lingulepis.
The Obolidae show some important features in the internal
impressions. Obolella crassa (Hall) may be taken as a well-
known type of the family. In this species a pair of small scars,
one on each side of the pedicle-groove, hes close under the
hinge line in the ventral valve. There is also a well-marked
scar for the insertion of the pedicle-muscle at the end of the
pedicle-groove. A pair of much elongated lateral impressions
extending forward from the “cardinals” may be homologous
with the “laterals” of Lingula; and the two small central scars
between them may be compared with the “ centrals” of Lingula
which are in a somewhat similar position. In the dorsal valve
of O. crassa a pair of “cardinals” is found, and on each side of
a low median rounded ridge are two small “central” scars.
Indistinct “lateral” scars arise close to or in the central area,
-and diverge anteriorly.
Sometimes a great concentration of muscle-scars occurs
round the foramen in the ventral valve, as in Stphonotreta.
As regards the minute structure and composition of the shell
in the Ecardines, we find that the Lingulidae and Discinidae
have their shell composed of alternating layers of phosphate of
lime and a corneous substance; the former layers are pierced
by microscopic canals. The Craniidae have calcareous shells
traversed by tubules, which divide into many fine branches near
the external surface; a thin periostracum covers the exterior.
The Trimerellidae have heavy thick calcareous shells, for which
they required the previously-described elaborate arrangement of
muscles to open and shut them.
XVIII TESTICARDINES: EXTERNAL CHARACTERS 497
Il. TESTICARDINES
External Characters
It is to this division that the great majority of the Brachio-
poda belong; and the diversity of form, of ornamentation, and
of internal characters is correspondingly greater than in the
Ecardines.
A transversely cr longitudinally oval shape of shell is the
commonest; but sometimes it is triangular, as in Rhynchonella
(Fig. 327), or bilobed, as in Pygope (= Terebratula diphya).
The ventral valve is usually more convex than the dorsal, and
the former may be prolonged into a tube by the accelerated growth
and infolding of the anterior and lateral margins, producing a
very abnormal form (Proboscidella). The external surface of
the valves is frequently ornamented with more or less prominent
radiating ribs; and fine concentric growth-lines are commonly
shown, and may be developed into coarse ridges or wrinkles,
particularly in old individuals. The members of the family
Productidae are usually furnished with tubular spines, which
are sometimes of great length, and served to anchor the free
shells in the mud, or were twisted round Crinoid stems and
similar objects.
In the ventral valve of many genera there is a median sinus,
with a corresponding fold in the dorsal valve, and rarely vice
versdé; sometimes the fold and sinus are double.
The hinge line is either curved or straight, and the valves
are articulated by means of a pair of “hinge-teeth” (Fig. 329, ¢)
in the ventral valve, which fit into corresponding sockets in the
opposite valve. Some genera have the teeth very rudimentary,
or have lost them altogether. The teeth are frequently sup-
ported by “dental plates,” and the sockets by “socket plates ”
(e.g. Conchidium, Figs. 324, 825). A few genera with a long
hinge line have the whole of it denticulated (Stropheodonta).
In the dorsal valve medianly close under the hinge line is a
shelly protuberance —the ‘cardinal process””—to which the
diductor muscles are attached. It is sometimes of great length
and forked (Stringocephalus, Fig. 826), or tripartite, or even
quadripartite ; but in Rhynchonella and some other genera it is
rudimentary.
VOL, Ill 2K
498 FOSSIL BRACHIOPODA CHAP.
A “hinge area” (Fig. 334, ¢.a) is often present on one or
both valves, and may be of great size, as in Clitambonites, but in
Productus it is wholly absent. In those genera that possess it a
triangular fissure —the “deltidial fissure” — frequently traverses
aie’, mes
Fic. 325.—Conchidium galea-
tum. Transverse section.
d, Dorsal valve; d.s, dorsal
septum; s, socket plate; v,
Fig. 324. — Conchidium galea- ventral valve; v.s, ventral
tum. Wenlock Limestone. septum; d.p, dental plate.
it on both valves; in the dorsal valve the fissure is merely the
space between the dental sockets, and may be occupied by the car
dinal process (Fig. 334, C) or covered by a shelly plate — the
‘chilidium.” In the ventral valve it gives passage to the pedicle,
Fic. 326.— Stringocephalus Burtini. (Modified from Woodward.) Devonian. A,
Interior of dorsal valve. B, Side view of interior of shell; «@, adductor (= occlusor)
sears; c, crura; c.p, cardinal process; d.s, dorsal septum; h.p, hinge plate;
l, brachial loop; s.p, shelly processes; t.s, dental sockets; v.s, ventral septum.
and may be partly or entirely closed by a similar plate (Fig.
334, d) known as the ‘“ pseudo-deltidium,” especially large in
Clitambonites, or remain open (Orthis). This pseudo-deltidium
is a primitive character, and arises in an early stage of the
XVIII TESTICARDINES: “INTERNAL CHARACTERS 499
development as a shell-growth on the dorsal side of the animal,
becoming attached to the ventral valve subsequently. The
pedicle in many genera passes out through a special foramen in
the beak of the ventral valve ; and its proximal portion is often
embraced by a pair of small plates — the deltidial plates or “ del-
tidium”’ — which are formed on lateral extensions of the ven-
tral mantle lobe, according to Beecher. These plates he on
each side of the pedicle, or grow round and unite in front of it
(Rhynchonella, Fig. 327), or constitute merely its anterior border
(Terebratula, Fig. 828). In some cases this foramen becomes
closed in old age.
The dorsal valve in a few cases has its beak perforated by a
a f P
.. eel wee
Fic. 327.— Rhynchonella ad
Boueti. .(Cornbrash.) Fic. 328. — Terebratula sella.
d, Deltidium; f, fora- (Lower Greensand.) d, Del-
men. tidium; /, foramen.
foramen — the “ visceral foramen.” This foramen is in no way
connected with the pedicle foramen, but points perhaps to the
existence in the early Testicardinate genera of an anal aperture.
In Athyris concentrica (Devonian) this foramen is connected
internally with a cylindrical tube, which extends longitudinally
to about one-third the length of the valve. In Centronella the
aperture in the cardinal plate is rounded and complete; and in
Strophomena and its allies the opening hes between the cardinal
processes. If this feature is correctly interpreted, it suggests a
retrogression of the group since Palaeozoic times not only in
numbers, but in structure; and other evidence points the same
way.
Internal Characters
The interior of the shell is sometimes more or less divided up
by septa. A median septum occurs in one or both valves of
many generaasa low ridge or strongly developed partition (Wald-
500 FOSSIL BRACHIOPODA CHAP.
heimia, Fig. 829, ss; and Stringocephalus, Fig. 826, B, v.s). Con-
chidium (Fig. 825) has its dental plates of great size, and unit-
ing to form a V-shaped chamber or “spondylium,” supported by
a median double septum; and by means of these with a pair of
septa and the large socket-plates in the dorsal valve the interior
of the shell of this genus is divided up into several chambers.
The interiors of several other genera are somewhat similarly
divided up.
In the Carboniferous genus Syringothyris two special plates,
situated between the dental plates, are rolled into an incomplete
tube, so as to enclose probably the anal extremity of the ali-
mentary canal; and in several genera a sub-umbonal “ cardinal
Fic. 329. — Waldheimia (Magellania) flavescens. A, Interior of ventral valve: a,
adductor scars ; v.a, ventral adjustors; d, divaricators ; a.d, accessory divaricators ;
p, peduncular muscle; dm, deltidium; /, foramen; ¢, teeth. B, Interior of dorsal
valve: a.a, anterior adductor (occlusor) scars; a.p, posterior adductor (occlusor)
scars; ¢.p, cardinal process; er, crura; d.s, dental sockets; Ap, hinge-plate; J,
brachial loop; ss, septum. (After Davidson.)
plate” is present, which is perforated (Athyris) or slit in some
cases for the passage of the anal tube.
For the support of the fleshy “spiral arms ” the calcareous
structures forming the “brachial apparatus” are of two main
types —(1) the loop type; (2) the spiral-cone type. In the
Strophomenidae no special calcareous support seems to have been
usually present (Fig. 834), though in some species of Leptaena
spirally-grooved elevated areas supported the fleshy arms; in the
Productidae it is probable that the ridges enclosing the ‘“ reni-
form impressions” (Fig. 333, 7) served for a similar purpose.
The Terebratulidae show the “loop type” of brachial appa-
ratus. In Waldheimia (Fig. 829), which may be taken as an
XVIII TESTICARDINES: INTERNAL CHARACTERS Sor
example, we notice first in the dorsal valve the “crura” (cr),
from which arise the two “descending branches” which run
forwards and then are bent back to form the ‘ascending
branches” which are united by the “ transverse band.” In some
genera the “ascending branches” may be reduced to mere
points, and the “transverse band” become a median vertical
plate; the “crura,” too, may be fused so as to form a “crural
band”; and the “descending branches” may be connected by a
cross band — the “jugal band.” In Stringocephalus (Fig. 826, 1,
s.p) the loop is furnished on its inner edge with radiating pro-
cesses; and in Argiope the loop is simple, not reflected, and
fused with marginal septa; while in the Thecidiidae it is more
or less fused with the shell itself, and with the mass of calca-
reous spicules secreted by the mantle.
The “spiral-cone type” of brachial apparatus is found in the
Spiriferidae, Atrypidae, and Koninckinidae, and consists of two
spirally-enrolled calcified lamellae, forming two cones with their
apices directed laterally GSpirifera, Fig. 330), or towards the
interior of the dorsal valve (Atrypa, Fig. 332), or towards
each other (Glasszia); or forming two flat spirals in the same
plane (Koninckinidae). A “jugal band” is generally present,
but varies much in _ posi-
tion, and in some genera
has complicated posterior
processes.
The Rhynchonellidae
have no loop or spiral
cones, but merely a pair
of short “ crura.”
The principal modifica-
tions in the attachments
of the muscles in the Tes-
ticardines are illustrated by Productus giganteus (Fig. 383),
Leptaena rhomboidalis (Fig. 334), and Waldheimia jlavescens
(Fig. 329).
In Productus (Fig. 333) we see in the ventral valve a pair
of dendritic occlusor, often called adductor, impressions and a
pair of large flabellate divaricator impressions. In the dorsal
valve the large “cardinal process” served for the attachment
of the divaricator, and a low median septum separated the den-
Fic. 330.—Spirifera striata. (Carboniferous
Limestone.) Showing brachial spires.
502 FOSSIL BRACHIOPODA CHAP,
dritic occlusor scars, which are rarely divisible into anterior and
posterior pairs.
In Leptaena (Fig. 334) the occlusor scars (a) in the ventral
6
CK
~
Fic. 331.— Atrypa reticu- Fig. 332. — Interior of the same, seen
laris. (Wenlock Lime- from the dorsal side, showing
stone.) brachial spires. (After Hall.)
valve are narrow and median, and are enclosed by a pair of
flabelliform divaricator impressions (d.v); in the dorsal valve
two pairs of occlusor scars (a.a, p.a) are well marked, and ac-
cessory posterior occlusor scars are traceable in some specimens.
fl
i
7H | Ih
j por
fall
A
Si ANY
| NN ae
h i"
AO Bae \
*) f
u f
mn i
(7,
biehis
’
{iH i
{IN
\ \
IH ith
I \)
th)
uy fs
i
,
|
Fic. 333. — Productus giganteus. (After Woodward.) Carboniferous Limestone. A,
Interior of dorsal valve. B, Interior of ventral valve. C, Transverse section
of valves. D, Hinge line of A: a, occlusor scars; d, divaricator sears; i, ‘‘ reni-
form impressions’’; ca, cardinal process; h, hinge line; p, brachial prominence;
8, cavity for spiral arms; do, dorsal valve; ve, ventral valve.
The vascular sinuses (v.s) and genital areas are conspicuous in
many species of this and other genera.
In Waldheimia (Fig.329) a sub-umbonal “ peduncular muscle”
XVIII TESTICARDINES: INTERNAL CHARACTERS 503
scar (p) in the ventral valve has before it a pair of ‘accessory
divaricator” scars (a.d) flanked by a pair of “ ventral adjustor ”
(v.a) and a pair of “ divaricator ” impressions (d@), between which
he the two occlusor scars (a). In the dorsal valve anterior
and posterior pairs of occlusor scars (a.a, ap) are visible.
The minute structure of the calcareous shell of the Testi-
cardines is of flattened fibrous prisms inclined at a very acute
Fia. 334. — Leptaena rhomboidalis. (Silurian.)
A, External view of ventral valve. B, In-
terior of ventral valve: a, occlusor scars;
d, pseudo-deltidium ; d.v, divaricator scars;
c.a, hinge area; ¢, teeth. C, Interior of
dorsal valve: a.a, anterior occlusor scars;
p-.d, posterior oc-
clusor scars; C.d,
hinge area; ¢.p, car-
dinal process; d,
chilidium ; s, dental
sockets; v.s, vascu-
lar sinuses.
NINN 4
angle to the surfaces. In many forms minute tubes more or
less closely arranged pierce through the fibrous shell-substance ;
but in some genera (Productus) they do not reach the outer
surface (see p. 468). Allied genera, however, differ much in
the punctate or impunctate character of the shell.
SYNOPSIS OF FAMILIES
I. EcCARDINES
Family. Lingulidae
Shell elongated, composed of alternating chitinous and calcareous layers,
the latter of which are perforated. Attached by a pedicle passing between
apices of valves.
Arms have no calcified supports.
(For muscles see Fig. 322.
Rance. — Lower Cambrian to Recent.
PRINCIPAL GENERA. — Lingula, Lingulella, Lingulepis.
504 FOSSIL BRACHIOPODA CHAP.
Family. Obolidae
Shell varies in shape. Ventral valve provided with pedicular groove
or foramen. Cardinal border thickened. No brachial supports. Shell
composed of alternating chitinous and calcareous layers.
(For muscles see p. 496.)
RanGE. — Lower Cambrian to Devonian.
PrincipaL GENERA. — Obolus, Obolella, Kutorgina, Linnarssonia, Siphono-
treta, Acrotreta, Neobolus.
Family. Discinidae
Shell rounded, valves more or less conical, fixed by pedicle passing
through slit or tubular foramen in ventral valve. No calcified brachial
supports. Shell structure chitino-calcareous.
RANGE. — Ordovician to Recent.
PRINCIPAL GENERA. — Discina, Orbiculoidea, Trematis.
Family. Craniidae
Shell calcareous, subcircular; fixed by surface of ventral valve; dorsal]
valve the larger, depressed-conical. Shell structure punctate.
Four principal muscular scars in each valve, with central triangular pro
tuberance in ventral valve (see p. 476).
RANGE. — Ordovician to Recent.
PRINCIPAL GENUS. — Crania.
Family. Trimerellidae
Shell thick, calcareous, inequivalve; beak of ventral valve usually
prominent; rudimentary teeth may be present; hinge area well developed,
with pseudo-deltidium. In interior of valves muscular platform, “crescent,”
and sometimes sub-umbonal chambers (see p. 494, Fig. 323).
RanGE. — Ordovician and Silurian; maximum in Wenlock.
PRINCIPAL GENERA. — Trimerella, Monomerella, Dinobolus, Rhinobolus.
II. TEsTICARDINES
Family. Productidae
Shell entirely free, or fixed by ventral valve or spines. Concayo-convex,
more or less covered with tubular spines. Hinge line straight. Hinge-
teeth absent or rudimentary.
Cardinal process prominent.
Reniform impressions in dorsal valve.
(For muscular impressions see p. 501, Fig. 333.)
RANGE. — Silurian to Permian. Genus Productus very characteristic of
the Carboniferous.
PRINCIPAL GENERA. — Productus, Chonetes, Strophalosia, Proboscidella,
Aulosteges.
XVIII SYNOPSIS OF FAMILIES 505
Family. Strophomenidae
Shell very variable in shape ; concavo-convex, plano-convex, or biconvex;
hinge line usually straight; frequently with an areaon each valve; foramen
may or may not be present. Shell structure near always punctate. Ventral
valve usually furnished with hinge-teeth; and dorsal valve with cardinal
process.
Brachial supports completely absent or very rudimentary.
(For muscular impressions see p. 502, Fig. 534.)
Rance. — Wholly Palaeozoic.
PRINCIPAL GENERA. — Orthis, with many sub-genera, Clitambonites,
Skenidium, Strophomena, Orthothetes, Leptaena, Stropheodonta, Plectambonites.
Family. Koninckinidae
Shell plano-convex or concavo-convex. Brachial apparatus composed of
two lamellae spirally enrolled in the same plane, or in the form of depressed
cones, with the apices directed into the ventral valve.
RANGE. — Silurian to Lias.
PRINCIPAL GENERA. — Koninckina, Koninckella, Coelospira, Davidsonia.
Family. Spiriferidae
Shell biconvex. Brachial apparatus consisting essentially of two
descending calcareous lamellae which by spiral enrolment form a pair of
laterally-directed cones (Fig. 330).
RANGE. — Chiefly Palaeozoic, but a few forms pass up into the Lias.
PRINCIPAL GENERA. — Spirifera, Cyrtia, Uncites, Athyris, Merista.
Family. Atrypidae
Brachial apparatus consists of two descending calcareous lamellae
which bend outwards at the extremity of the crura and are coiled into two
spiral cones, the apices of which either converge towards each other
(Glassia) or towards the dorsal valve (Atrypa, Fig. 352), or diverge towards
the dorsal valve (Dayia); shell structure impunctate.
RANGE. — Ordovician to Trias.
PRINCIPAL GENERA. — Atrypa, Dayia, Glassia.
Family. Rhynchonellidae
Shell biconvex, hinge line usually curved.
Beak of ventral valve incurved, with foramen.
Calcareous brachial supports reduced to a pair of short curved crura.
The septa, dental and socket plates may be highly developed and divide
up the cavity of the shell into chambers (Stenochisma, Conchidium).
Shell structure fibrous, rarely punctate; muscular impressions as in
Terebratulidae.
Rance. — Ordovician to Recent: majority of the genera are Palaeozoic.
PRINCIPAL GENERA. — Rhynchonella (Fig. 327), Stenochisma, Stricklan-
diu, Conchidium.
506 FOSSIL BRACHIOPODA CHAP,
Family. Terebratulidae
Shell structure punctate.
Arms supported by a calcareous loop, usually bent back on itself.
(For muscular impressions see p. 502, Figs. 328, 329.)
Beak of ventral valve perforated by foramen, furnished with deltidium.
RANGE. — Devonian to Recent; maximum development in Mesozoic
times.
PrincrpaAL GENERA. — Terebratula, Terebratulina, Waldheimia, Terebra-
tella, Kingena, Magas, Centronella.
Family. Argiopidae
Large foramen for passage of pedicle. Marginal septa present in both
valves. Calcareous brachial loop follows margin of shell and is more or
less fused with the septa. Shell structure punctate.
RANGE. — Jurassic to Recent.
PRINCIPAL GENERA. — Argiope, Cistella.
Family. Stringocephalidae
Shell subcircular, punctate. Cardinal process highly developed, bifid.
Brachial apparatus composed of two calcareous free lamellae, prolonged at
first downwards, then bent back, upwards and outwards to run parallel to
margin of shell and to unite in front, thus constituting a wide loop.
RanGeE. — Silurian and Devonian.
SOLE GENus.— Stringocephalus.
Family. Thecidiidae
Shell usually fixed by beak of ventral valve, plano-convex. Sub-cardinal
apophysis in ventral valve for attachment of occlusors. Marginal septa in
dorsal valve. Caleareous brachial loop more or less fused with shell, and
with calcareous spicules of mantle. Shell structure: inner layer fibrous,
outer layer tubulated.
RANGE. — Carboniferous to Recent.
PRINCIPAL GENERA. — Thecidium, Oldhamina.
STRATIGRAPHICAL DISTRIBUTION OF BRACHIOPODA
It is remarkable that some of the earliest types of Brachio-
poda exist generically unchanged at the present day. Such are
Lingula, ranging from the Cambrian; Discina and Crania, ranging
from the Ordovician; and amongst the hinged forms Terebratula
from the Devonian, and Rhynchonella from the Ordovician.
In the lowest Cambrian (Olenellus beds) the most important
genera are Linnarssonia and Kutorgina. The hinged forms
appear in the Cambrian, being represented by Orthis; but the
majority in this formation belong to the Ecardines. Lingula,
Linyulella, and Obolella are characteristic.
XVIII STRATIGRAPHICAL DISTRIBUTION 507
In the Ordovician many new genera of the Testicardines
make their appearance, such as Strophomena, Leptaena, Atrypa,
LRhynchonella, Clitambonites, etc., but the extraordinary abun-
dance and variety of Orthis is most remarkable. The Ecardines
are reinforced by such forms as Trematis and Siphonotreta. It
is, however, in the Silurian that the Testicardinate Brachiopoda
attain their maximum, for in addition to a great development
of species amongst the older forms, a host of new genera for the
first time occur here (Spirifera, Athyris, Conchidium, Stricklan-
dia, Chonetes, Cyrtia, etc.); and the Trimerellidae are especially
characteristic of the Wenlock.
With the commencement of Devonian times many species
and genera become extinct, but new forms come in ( Terebratula,
Orthothetes, Productus, etc.), and some genera are wholly con-
fined to this formation ( Uneites, Stringocephalus). The Carbonife-
rous is marked by the maximum development of Productus and
Spirifera; Orthothetes, Stenochisma, and Athyris are also abun-
dant, but there is a considerable extinction of the older genera
and species, and a great diminution in the number of individuals
and species of those that persist.
A further reduction occurs in the Permian, where the most
important genera are Productus, Strophalosia, and Stenochisma ;
but Aulosteges is a new form peculiar to this period. In the
Trias a new era commences; the principal families and genera
of the older rocks disappear entirely; a few spire-bearing genera
persist (Spiriferina, Athyris), and the genus Moninckina is
restricted to this formation.
The enormous development of species of the Terebratulidae
and Rhynchonellidae is the most noticeable feature in Jurassic
times; and a few ancient types linger on into the Lias GSpori-
ferina, Suessia, asub-genus of Spirifera); Koninckella here occurs.
The Cretaceous Brachiopoda are closely allied to the Juras-
sic; Magas and Lyra are peculiar to the period, and the Tere-
bratulidae and Rhynchonellidae are very abundant, together with
the Ecardinate genus Crania.
With the commencement of Tertiary times the Brachiopoda
have lost their geological importance, and have dwindled down
into an insignificant proportion of the whole Invertebrate fauna.
The distribution of the Brachiopoda in past time is shown
in the following table: —
508
FOSSIL BRACHIOPODA
ECARDINES
Lingulidae
Obolidae
Discinidae
Craniidae
Trimerellidae
Lingula. .
Lingulella .
Obolus .
Obolella
Kutorgina .
Linnarssonia .
Trematis
Siphonotreta .
Acrotreta .
Discina .
Crania .
Trimerella.
Dinobolus .
TESTICARDINES
Productidae
Strophomenidae
Koninckinidae
Spiriferidae
Atrypidae
Rhynchonellidae
Terebratulidae
Argiopidae
Stringocephalidae
Thecidiidae
Productus .
Chonetes
Strophalosia
Orthis
Skenidium .
Clitambonites
Strophomena .
Stropheodonta
Leptaena
Orthothetes
Davidsonia
Koninckina
Koninckella
Spirifera
Spiriferina .
Cyr: ei 4
Syringothyris .
Uncites . :
Athyris.
Merista .
Retzia .
Atrypa .
Dayia
Coelospira .
Rhynchonella
Stenochisma .
Stricklandia
Conchidium
Terebratula
Terebratulina
Waldheimia
Terebratella
Kingena
Magas . .
Centronella
Argiope .
Cistella .
Stringocephalus
Thecidium .
Oldhamina
;
| Carboniferous
| Permian
| Jurassic
Recent
| Ordovician
| Devonian
| Silurian
| | Cretaceous
| | Tertiary
| | Trias
| | | | | | Cambrian
XVIII PHYLOGENY AND ONTOGENY 509
PHYLOGENY AND ONTOGENY
Wherever successive stages in the life history of an individual
resemble in important anatomical features the adult individuals
of other species occurring in successive members of a strati-
graphical series, the development of the individual may be
regarded as an epitome of the development of the species; it
also generally throws light on the origin and relationships of
allied genera and families.
In the case of the fossil Brachiopoda comparatively little
work has yet been done in tracing their ontogeny or phylogeny,
though the abundance, variety, and excellent state of preserva-
tion of the extinct species offer a promising field for investi-
gation. It is to Dr. C. E. Beecher and other recent American
palaeontologists that we owe our advance in this branch of the
subject.
In the first place, in about forty genera, representing nearly
all the leading families of the group, the important fact has
been established of the presence of a common form of embryonic
shell, termed the “ protegulum,” which is “ semicircular or semi-
elliptical in shape with a straight or arcuate hinge line and no
hinge area” (Beecher).! Its minute size and delicate texture
cause its preservation to be rare, but its impression is not
uncommonly left on the beak of the adult shell.
The main features of this embryonic shell are exhibited in
the adult Lower Cambrian Brachiopod Obolus ( Kutorgina) labra-
doricus (Billings); the sub-equal semielliptical valves have lines
of growth running concentrically and parallel to the margin of
the shell, and ending abruptly against the straight hinge line;
and this indicates that there has been no change in the outline
and proportions of the shell during its stages of growth, but
only a general increase in size. It is very significant that we
have here a mature type possessing the common embryonic
characters of a host of widely separated genera, and we may
therefore regard it as the most primitive form known.
Many genera pass through this so-called “ Paterina” stage
either in the case of both their valves, or more generally in the
case of the dorsal valve only; but modifications in the form
of the protegulum arise, which are due to the influence of
1 Amer. Jour. Science, 1890-1893.
510 FOSSIL BRACHIOPODA CHAP.
accelerated growth, by which features belonging to later stages
become impressed on the early embryonic shell. The most
variable and specialised valve — the ventral or pedicle valve —
naturally exhibits the effect of this influence first and to the
greatest extent. The Palaeozoic adult forms of many species
represent various pre-adult stages of the Mesozoic, Tertiary, and
Recent species, as is especially well shown in the genera Orbi-
culoidea and Discinisea.
In the Strophomenoid shells the protegulum in the dorsal
valve is usually normal, but in the ventral valve abbreviation
of the hinge and curvature of the hinge line are produced by
acceleration of the “ Discinoid stage” in which a pedicle notch
is present.
No marked variation has yet been noticed in the spire-bearing,
or Terebratuloid, or Rhynchonelloid genera.
The form of the shell and the amount of difference in shape
and size of the valves seem to be largely due to the length of
the pedicle and its inclination to the axis of the body, as evi-
denced by the development of Terebratulina. A series showing
progressive dissimilarity of the two valves arising from these
causes can be traced from Lingula to Crania. The greater
alteration that takes place in the ventral valve appears to be
due to its position as lower and attached valve. If the pedicle
is short a transversely-expanded shell with long hinge line results
when the plane of the valves is vertical or ascending, but when
the latter is horizontal a Discinoid form is found. This mode
of attachment is often accompanied by a more or less plainly
developed radial symmetry. Shells with long pedicles, on the
other hand, are usually longer than wide.
The character of the pedicle-opening is of great significance
from an evolutional and classificatory point of view, for the
successive stages through which it passes in embryonic growth
are chronologically paralleled by different genera, and are like-
wise accompanied by the successive acquisition of other important
anatomical characters, as has been shown by Beecher and others.
The first and simplest type of pedicle opening is in shells with a
posterior gaping of the valves, where the pedicle protrudes freely
between them in a line with the axis, and the opening is shared
by both valves, though generally to a greater extent by the ven-
tral valve. Paterina (= Obolus labradoricus) and Lingula furnish
XVIII PHYLOGENY AND ONTOGENY Bt
examples of this type. In the second type the pedicle opening
is restricted to the ventral valve, and the direction of the pedicle
makes a right angle with the plane of the valves; in the lower
forms the pedicle lies in a slit or sinus ( Trematidae), but by fur-
ther specialisation it becomes enclosed by shell growth so as to lie
within the periphery, and finally becomes subcentral in some
genera (Discinidae). The third type shows the pedicle opening
confined to the ventral valve and submarginal. A pseudo-delti-
dium may preserve the original opening ( Clitambonites) ; or this
shelly plate may become worn away or reabsorbed in the adult
so that the deltidial fissure through which the pedicle passes
remains quite open (Orthidae). In the fourth type the incipient
stage marks a return to the simple conditions of the first type ;
but ultimately a pair of deltidial plates develop, and may com-
pletely limit the pedicle opening below. Examples of this type
are Spirifera and Rhynchonella. By means of these four types
the Brachiopods have been divided into four Orders: the Atre-
mata (type i.); the Meotremata (type i.); the Protremata
(type ii.); and the Telotremata (type iv.).
The Telotremata were the last to appear, but the four types of
pedicle-opening with the various forms of calcareous brachial
apparatus were in existence in the Bala period of the Ordovician.
As Paterina is the most primitive form of all, we may place it
at the root of the phylogenetic tree. From it sprang the Atremata,
which gave off the Neotremata and Protremata; the most primi-
tive Neotremata seem to be the Trematidae, while the connecting
link between the Protremata and Atremata is furnished by the
Kutorginidae. From the genus Conchidium and its allies we
may see how the Rhynchonellidae ushered in the Telotremata as
an offshoot from the Protremata. The Telotremata subsequently
gave off two main branches, which became specialised with the
loop-bearing and spire-bearing forms respectively.
The evolution and mutual relationships of genera have been
indicated with much probability by Hall, Clarke, and others.
The Obolelloid type may be connected with the Linguloid by
means of Lingulella and Lingulepis, while in Lingula itself we
find the point of divergence for the ancestors of Zrimerella, and
for a line of variation culminating in Dignomia. The Palaeo-
zoic Rhynchonelloids branched off at an early period from the
same stock as Orthis, and are connecting links between this
512 FOSSIL BRACHIOPODA CHAP. XVIII
genus and Mesozoic Rhynchonellae ; and a whole series of genera
exhibit intermediate stages of structure between the Rhyncho-
nelloid and Pentameroid groups. The Terebratuloids can be
traced back to the primitive type Renssoellaria; and amongst
spire-bearing forms, the protean genus Spirifera can be split up
into groups of species which diverge along lines tending to forms
no longer congeneric. When we come to deal with specific
differences we find frequently such a host of intermediate varie-
ties that the separation of many species, as in the case of Mesozoic
Terebratulae, is to a large extent arbitrary and artificial.
INDEX
References to figures are printed in thick type (248, 197); to systematic position,
in italics (391, 430)
ABRALTIA, 391
Absorption of internal portions of
shell, 259
Abyssal Mollusca, 574
Acanthinula, 441
Acanthoceras, 399
Acanthochiton, 403, 403
Acanthodoris, 434
Acanthopleura, 408 ; eyes, 188
Acavus, 805, 304, 335, 441
Acera, 245, 430
Achatina, 278, ; 328- 337, 333, 442, 448 ;
jaw, 211; food, 39 ; size of egg, 124;
AN fulica, 279
Achatinella, 278, 326, 327, 443; radula,
234 ; musical sounds, 51
Achatinelloides, 332
Acicula, 287, 296, 414
Acmaea, 405 ; radula, 227
Acme, 414
Acmella, 314, 415
Acroptychia, 356, 414
Acrotreta, 504, 508
Actaeon, 250, 427, 428, 429; radula,
217, 250 ; streptoneurous, 203 n.
Actaeonella, 430
Actaeonia, 432
Actaeonina, 250, 429
Actinoceras, 394
Actinodonta, 447
Acusta, 305, 316, 318, 441
Adacna, 12, 297, 455
Adalaria, 434
Adamsiella, 414
Addisonia, 412
Adelphoceras, 395
Adeorbis, 416
Admete, 426
Aegires, 434
Aegista, 305, 316, 441
Aegoceras, 398
VOL. I
| Aeolis, 10, 152, 482; radula, 217,
229; stinging cells, 65; mimicked
by Sagartia, 68; warning colora-
tion, 72
Aerope, 328, 383, 440;
habits, 54
Aestivation, 25
Aetheria, 328-336, 452 ; variation, 92
Africarion, 335, 440
Agaronia, 426
Age of snails, 39
Aglossa, 7
Agnatha, habits, 51
Akiodoris, 434
Alaba, 415
Alaria, 418
radula, 215;
: Alariopsis, 420
Albersia, 320
Albino varieties, 87
Alcadia, 348-551, 410
Alderia, 432
Alexia, 439
Alicia, 459
Allognathus, 441
Allopagus, 452
Alloposidae, 384
Alvania, 415
Alycaeus, 266, 302 f.,
Amalia, 440
Amalthea, 78
Amaltheus, 398
Amastra, 443
Amaura, 411
Amberleya, 409
Ambonychia, 449
Amicula, 404
Ammonites, 247, 393, 398, 398; sutures,
396 ; aptychus, 397
Ammonoidea, 396 f.
Amnicola, 325, 415
Amoria, radula, 222
3 21
309, 319, 414
514
Ampelita, 535, 442
Amphibola, 10, 18, 439; breathing,
161; radula, 236
Amphibulimus, 352, 442 ;
Amphidoxa, 358
Amphidromus, 301, 305, 317, 310, 559,
442; radula, 2383
Amphineura, 8, 400; breathing organs,
154, 168 ; nervous system, 208 ; geni-
talia, 145
Amphipeplea, 439
Amphiperas, 419
Amphisphyra, 430
Amphissa, 423
Amphitretus, 383
Ampullaria, 17, 416; self-burial, 42;
spawn, 125; breathing organs, 151,
158 ; jaws, 212; shell, 249, 263; oper-
culuin, 268; distribution, 294, 320,
322, 343, 359
Ampullarina, 302, 439
Ampullina, 411
Amussium, 450
Amycla, 423
Anabathron, 415
Anachis, 423
Anadenus, 24, 441
Anal glands, 241
Anal siphon, 164, 173
Anastomopsis, 442
Anatina, 274, 275, 459
Anatinacea, 458; gills, 167
Anaulus, 414
Anchistoma, 293, 296
Ancilla, 267, 426
Ancillina, 426
Ancistrochirus, 391
Ancistromesus, 405
Ancistrotenthis, 391
Ancula, 484; radula, 229, 230; warn-
ing coloration, 72
Anculotus, 417
Ancyloceras, 247, 399
Ancylus, 19, 439; breathing,
hibernating, 27; radula, 235
Aneitea, 325, 443
Angitrema, 540, 417
Anisocardia, 451
Anodonta, 259, 341, 452; shower of, 47;
variation, 92 ; Glochidium, 147; gill,
167 ; otocyst, 197; nervous system,
206 ; hinge, 274; A. anatina, 24; dis-
tribution, 282
Anodontopsis, 451
Anoglypta, 325, 441
Anomia, 257, 448, 464; intestine, 241;
byssus hole, 262; hearing, 196
Anomiacea, £48
Anoplophora, 451
Anostoma, 248, 266, 356, 3858, 442;
aperture, 63
Anthracosia, 451
radula, 233
162 ;
MOLLUSCA — BRACHIOPODA
Anura, 424
Anus, 209, 241
Apera, 334, 440
Aperostoma, 544, 414
Aphanotrochus, 408
Aphelodoris, radula, 230
Apicalia, 422
Aplacophora, 9, 404; radula, 228
Aplecta, 354, 439
Aplustrum, 245, 428, 430; radula, 230
Aplysia, 245, 428, 431; stomach, 239;
purple fluid, 65
Aplysioidea, 430
Aporrhais, 418 ; radula, 216
Apricardia, 455
Aptychus, 397
Aptyxiella, 417
Aptyxis, 424
Aral Sea, Zimnaea from near, 84;
Cardium from, 91
Arca, 14, 171, 278, 448; eyes, 191
Arcacea, 448
Arcachon, oyster-parks at, 105
Arcestes, 397
Archidoris, 434, 434; protective colora-
tion, 78
Architeuthis, 578, 390, 390 ; sucker, 381
Arcomya, 458
Arconaia, 307, 452
Arctic shells, colour of, 86
Arcuella, 422
Argiope, 470, 472, 479, 487; parasite
of, 485; distribution, 486; fossil,
501, 506, 508
Argiopidae, 506, 508
Argobuccinum, 420
Argonauta, 383, 383; egg-laying, 127;
hectocotylised arm, 137; radula, 236
Arinia, 413
Ariolimax, 441, 341, radula, 233
Arion, 440; shell, 175, 245, 246 ; hardier
than Helix, 24; voracity, 50 f.; egg-
laying, 42 f.; protective coloration,
70; pulmonary orifice, 160; food,
179; smell, 193 f.; radula, 233; dis-
tribution, 285
Arionta, 341, 353, 441
Ariophanta, 31, 308, 309, 316, 440;
protective coloration, 70
| Aristotle, on modified arm of polypus,
138
Artemis, 454
Arthuria, 403:
Asaphis, 456
Ascoceras, 394
Ascoglossa, 11 n., 437
Ashford, C., on pulsations of heart in
Helix, 26; on homing of Helix, 35;
on dart-sac, 143
Asolene, 416
Aspergillum, 262, 459
Aspidelus, 329, 440
INDEX
Aspidoceras, 399
Assiminea, 415
Astarte, 451
Asthenothaerus, 459
Astralium, 409
Athoracophorus, 4435 — see Janella
Athyris, 499, 500, 505 ; stratigraphical
distribution, 507, 508
Atilia, 423
Atlanta, 421, 422; foot, 200
Atopocochlis, 350, 441
Atremata, 511
Atretia, distribution, 486, 487
Atrypa, 501, 502, 505; stratigraphical
distribution, 507, 508
Atrypidae, 501, 505, 508
Aturia, 393, 395
Atys, 428, 430
Aucapitaine, H., on tenacity of life, 58
Aucella, 449
Aulopoma, 157, 304, 474; operculum,
269
Aulosteges, 504; stratigraphical distri-
bution, 507
Auricula, 439, 439
Auriculella, 327, 443
Auriculidae, 17, 18, 260, 4389, 439;
lung, 160; eyes, 186; radula, 255
Austenia, 301, 304, 440
Avellana, 430
Avicula, 254, 258, 449, 449; eyes, 190 ;
genital orifice, 242 ; A. margaritifera,
100
Aviculopecten, 450
Aviculopinna, 449
Axinus, 452
Azeca, 442
Azygobranchiata, 155, 407
BABINKA, 447
Bactrites, 395
Baculites, 399
Baikalia, 290, 415
Baird, Mr., on the British Museum
snail, 37
Balea, 442; B. perversa, 24, 41
Baltic, fauna of the, 12, 83, 366
Bankivia, 408
Barbatia, 448
Barleeia, 415
Barnacle, Rev. H. G., on musical
sounds, produced by Mollusca, 51
Barometers, snails as, 50
Bartlettia, 452
Basilissa, 376, 408
Basommatophora, 11, 19, 181, 438
Basterotia, 451
Bateson, W., on variation in Cardium,
91; on hearing in Anomia, 196
Bathmoceras, 395
Bathydoris, 433
Bathyteuthis, 390
515
Batissa, 320, 452
Beddomea, 304
Beecher on phylogeny, 509
Beetles, prey on Mollusca, 58
Bela, 426 ; radula, 219
Belemnites, 380
Belemnitidae, 387
Belemnosepia, 390
Bellerophon, 266, 407
Belopetra, 580
Belopteridae, 388
Belosepia, 386, 388
Beloteuthis, 390
Bembizx, 376, 408
Benedictia, 290, 415
Benthobia, 577
Benthodolium,
Berendtia, 441
Beudant, experiments on Mollusca, 12
Bideford Bridge and mussels, 117
Binney, Dr., on epiphragm, 28
Onn
oli
| Binneya, 341, 441
| Biradiolites, 456
Birds, devour Mollusca, 56 f.
Bithynella, 289, 293, 415
Bithynia, 336, 342, 415 ; stomach, 239 ;
habitat, 25
Bittium, 416
Blaesospira, 346, 351
Blandiella, 16, 414
Blanfordia, 414
Blind Mollusca, 185
Blood, 171
Bodo, land Mollusca, 24
Boeuf and French oysters, 107
Bolma, 409
Boltenia, 346
Boreofusus, radula, 221
Bornella, 433 ; stomach, 259
Borsonia, 426
Borus, 356-358, 441
Bourcieria, 357, 410
Bourquetia, 417
Bourguignatia, 332
Bouvier — see Fischer
Boysia, 802, 442
Brachial apparatus, types of, 500
Brachiopoda, fossil, limestone formed
of, 492; shell, 493, 497 ; muscle scars
on, 494, 501; platform, 495; synopsis
of families, 503 ; stratigraphical dis-
tribution, 506; phylogeny and onto-
geny, 509; Orders, 511
Brachiopoda, recent, 463; historical
account of, 464; shell, 465; body,
469; digestive system, 471; body
cavity, 472; heart, 473; excretory
organs, 474; muscles, 475; nervous
system, 478; reproductive system,
478; embryology, 479; habits, 482 ;
distribution, 484; classification, 487 ;
affinities, 487
516
MOLLUSCA — BRACHIOPODA
Brachytrema, 417
Brackish-water species, 14
Branchiae, 151, 155, 164
Branchial siphon, 155, 164, 175
Braun, on self-impregnation, 44
Breathing organs— see Respiration,
Branchiae
Brechites, 459
Breeding, periodicity in, 129
Broderipia, 408
Brotia, 305
Brownia, 138
Buccinanops, 423
Buccinopsis, 424; radula, 221, 222;
egg-laying, 128
Buccinum, 6, 424; radula, 217; mon-
strosity, 251 ; breeding, 129 ; osphra-
dium, 195; spawn, 126
Buliminus, 24, 278, 285, 295 f., 316,
301, 339, 442; protective habits, 70 ;
B. pallidior, 38
Bulimulus, 278, 334, 339-359, 442;
jaw, 211, 233; radula, 233; varia-
tion, 87
Bulimus, 278, 542-359, 355,
radula, 238; egg, 124
Bulinus — see Isidora
Bulla, 428, 430
Bullia, 155, 423; habits, 192; foot,
198; radula, 221
Bulloidea, 429
Burrowing Mollusca, 446
Burying propensities of Mollusca, 27,
4]
Busycon, 424;
egg-capsules, 125— see Fulgur
Butterell, Mr., on habits of Testacella,
52
Byssocardium, 455
Byssus gland, 201
CADLINA, 434
Cadoceras, 393
Cadulus, 376, 445
Caecilianella, 442; habitat, 48 ; eyes,
186
Calcarella, 138
California, land Mollusca, 280
Calliostoma, 408 ; jaws, 212
Callistochiton, 403
Callochiton, 403
Callogaza, 408
Callonia, 442
Callopoma, 409
Calma, protective coloration, 74
Calybium, 410
Calycia, 320, 442
Calycidoris, 434
Calyptraea, 248, 412
Camaena, 305, 306, 315, 316, 441
Cambrian, Mollusca of the, 2
Camitia, 409
Bal |
money made from, 97; |
| Campaspe, 433
Camptoceras, 302
Camptonyx, 278, 302, 439
Campylaea, 285, 289 f., 298, 447
Canal, 155
Cancellaria, 426
Canidia, 16, 305, 423
Cannibalism in snails and slugs, 32,
33
Cantharidus, 408
Cantharus, 275; radula, 222
Caprina, 456
Caprotina, 456
Capulus, 412
Caracolus, 347-351, 441
Carbonicola, 451
Cardiacea, 454
Cardiapoda, 421
Cardilia, 454
Cardinal plate, 500
Cardinal process, 497, 501
Cardinalia, 408
Cardinia, 451
Cardita, 273, 451
Carditella, 451
Carditopsis, 451
Cardium, 6, 273, 455, 455; C. edule,
12, 164; modifications, 12; variation,
84, 91; nervous system, 207; distri-
bution, 292, 297
Carelia, 327, 443
Carinaria, 9, 422, 422; foot, 200
Carinifex, 439
Carolia, 448
Cartusiana, 296
Carychium, 18, 439
Caryodes, 325, 359, 441
Casella, radula, 230
Caspia, 12, 297
Caspian Sea, fauna, 12, 297
Cassidaria, 420
Cassidula, 18, 278, 489, 439
Cassis, 255, 420; radula, 223
Castalia, 344, 452
Cataulus, 157, 266, 804, 474
Caterpillars mimicking Clausilia, 68
Cathaica, 316, 441
Catinella, 443
Cavolinia, 158, 436; eyes, 186
Cecina, 414
Cenia, 432; breathing, 152
Centrodoris, 434; radula, 230
Centronella, 499, 506, 508
Cephalopoda, 378 f.; defined, 5; ink,
65; egg-laying, 127; embryo, 183;
branchiae, 168; osphradium, 195;
foot, 200; nervous system, 206 ;
jaws, 218; radula, 236
Cepolis, 349-351, 441
Cerastoma, 423
Cerastus, 331, 441
Cerata of Nudibranchs, 71, 159
INDEX
Ceratites, 397, 398 ;
Ceratodes, 357, 416
Ceres, 21, 354, 410
Ceritella, 417
Cerithidea, 260, 417; C. obtusa, breath-
ing, 152
Cerithiopsis, 417
Cerithium, 16, 416
Ceromya, 458
Chaetoderma, 404, 404; breathing
organs, 154; nervous system, 203;
radula, 217, 228
Chaetopleura, 403
Chama, 257, 272, 446, 455
Chamostrea, 458
Changes in environment, effect of, 83 f.
Chank-shell, fishery of, 100 |
Charis, 324, 442
|
suture, 396
Charopa, 319, 323-327, 441
Chascax, 424
Chelinodura, 430
Chelotropis, 135
Chenopus, 418
Chilidium, 498
Chilina, 19, 343, 358
Chilinidae, 439; radula, 236
Chilotrema, 441
China, use of shells in, 101
Chiropteron, 133
Chiroteuthis, 385, 391
Chiton, 8, 158, 403; egg-laying, 126;
breathing organs, 153 f.; eyes, 188; |
osphradium, 195; radula, 228; ner- |
vous system, 203; valves, 401, 402 ;
girdle, 403
Chitonellus, 404, 404; valves, 401
Chittya, 16, 348, 351, 414
Chlamydephorus, 333, 440
Chlamydoconcha, 175, 245, 453
Chlamys, 450
Chloritis, 306, 311, 819-3824, 447
Chlorostoma, 408
Chlorostracia, 807
Choanomphalus, 250, 290, 439
Chondrophora, 389
Chondropoma, 346-355, 348, 414
Chondrula, 285, 295, 296, 442
Choneplax, 404
Chonetes, 504; stratigraphical distribu- |
tion, 507, 508
Choristes, 420
Choristoceras, 398
Chorus, 423
Smo done, 4843 jaws, 212; radula,
230
Chrysallida,
Chrysodomus, 423
Chrysostoma, 409
Cingula, 415
Cingulina, 422
Cionella, 442
Circe, 454, 458
517
Circulatory system, 169
Circulus, 408
Circumpolar species, 287
Cirrhoteuthis, 381, 382
Cistella, 467, 470, 472, 475, 476, 479,
480, 487; larvae, 481, 485 ; parasite
of, 485 ; -listribution, 486 ; fossil, 506,
508
Cistopus, 385
Cistula, 349, 351, 355, 414
Cladohepatica, 432
Clanculus, 408
Classification, 5, 8 ; of Gasteropoda, 8,
Ait
Clathurella, 426
Clausilia, 442, 442; mimicked by cater-
pillars, 68; monstrosity, 251; dis-
tribution, 285 f., 294, 305-318, 382,
399-396 ; C. rugosa, 24 ; scalaris, 278
Clavagella, 262, 459
Clavator, 385, 359, 441
Clavatula, 426
Clavella, 424
Claviger, 329, 417
Clea, 16, 305, 423
Clementia, 454
Cleodora, 486, 436
Cleopatra, 294, 328, 331, 336, 416
Clessin, on duration of life, 39
Clessinia, 12, 297
Clio, 486, 436
Cliona, enemy of oysters, 112
Clione, 158, 438
Clionopsis, 437
Clitambonites, 498, 505; stratigraph-
ical distribution, 507, 508, 511
Clithon, 827, 410
Clydonites, 398
Clymenia, 397
Clypidella, 406
Cocculina, 408
Cochlicella acuta, 278
Cochliolepas, 77
Cochloceras, 398
Cochlodésma, 459
Cochlostyla, 124, 278, 318, 315, 441
Cockles, use of, 101, 118
Coecum, 247, 260, 417, 418
Coeliaxis, 334, 442; habitat, 49
Coelocentrum, 358, 442
Coelospira, 505, 508
Cold winter, effect on oysters, 112 ; on
mussels, 116
Collinge, W. E., on prowen and burial
of shells, 4]
OCollisella, 405
Collisellina, 405; radula, 227
Collonia, 409
Colobocephalus, 430
Colour of arctic shells, 86
Colpodaspis, 430
Columbarium, 426
518
MOLLUSCA — BRACHIOPODA
Columbella, 423; radula, 222
Columbellaria, 420
Columbellina, 420
Columna, 328, 330, 443
Cominella, 16, 424
Composition of shell, 252
Concha, 465
Conchidium, 497, 498, 500, 505 ; strati-
graphical distribution, 507, 508, 511
Concholepas, 267, 423
Conidea, 423
Conocardium, 455
Conorbis, 426
Conus, 247, 275, 426; poisonous bite,
65; tooth, 66; shell, 69, 255, 260;
mimicked by Strombus, 69; prices
given for rare, 121; spawn, 125;
radula, 218, 220; operculum, 269
Cookia, 409
Coptochilus, 314, 414
Coralliophaga, 451
Coralliophila, 75, 423
Coralliophilidae, radula, 216
Corambe, 434
Corasia, 311, 319-821
Corbicula, 15, 288, 292 f., 453
Corbis, 452
Corbula, 456
Corilla, 305
Corona, 27, 442
Coronaria, 297
Coryda, 346-551, 441
Coryphella, 432
Cosmoceras, 399
Cowry used as money, 96
Coyote trapped by Haliotis, 57
Oranchia, 391
Crania, 464, 467, 468, 469, 471, 472,
473, 475, 476, 477, 487; distribu-
tion, 485 ; fossil, 493, 494, 504 ; strati-
eraphical distribution, 506, 507, 508,
510
Craniidae, 487, 496, 504, 508
Cranopsis, 265, 406
Craspedochiton, 403
Craspedopoma, 298, 414
Craspedostoma, 408
Crassatella, 451
Cratena, 432
Crawling of Helix, 45
Cremnoconchus, 16, 302, 413
Crenatula, 75, 449
Crenella, 449
Crenipecten, 450 :
Crepidula, 248, 257, 412, 412; para-
Sitic, 78
Crepipatella, 248, 412
Creseis, 486, 436; eyes, 186
Crimora, 434; radula, 229
Crioceras, 247, 399, 399
Cristigibba, 311, 319, 320, 441
Crossostoma, 408
|
Crucibulum, 248, 412
OCryptochiton, 245, 371, 402, 404
Cryptochorda, 425
Cryptoconchus, 404
Cryptophthalmus, 430
Cryptostracon, 353, 441
Ctenidia, 151 — see Branchiae
Ctenopoma, 346-351, 414
Cucullaea, 274, £448
Cultellus, 457
Cuma, 423
Cumingia, 453
Cuspidaria, 459; branchiae, 168
Cuvierina, 4386, 436
Cyane, 410
Cyathopoma, 247, 268, 314, 338, 414
Cyclas, 453; veliger, 182; ova, 146;
otocyst, 197 ; C. cornea, thread-spin-
ning, 29; distribution, 282
Cyclina, 454
Cyclobranchiata, 156
Cyclocantha, 409
Cyclomorpha, 414
Cyclonassa, 423
Cyclonema, 409
Cyclophoridae, origin, 21
Cyclophorus, 302, 306-319, 829-334,
344, 352-358, 414 ; jaws, 212; radula,
21
Cyclostoma, 528, 331-388, 414, 414;
stomach, 239; vision, 184; osphra-
dium, 195; nervous system, 205; C.
elegans, 287, 288
Cyclostomatidae, origin, 21; radula,
224; gait, 199
Cyclostrema, 408
Cyclosurus, 247, 537, 414
Cyclotopsis, 338, 414
Cyclotus, 296, 319, 320, 414
Cylichna, 428, 430; radula, 215
Cylindrella, 247, 260, 278, 343-355,
348, 442; monstrosity, 251, 252
Cylindrellidae, radula, 233, 234
Cylindrites, 430
Cylindrobulla, 430
Cylindromitra, 425; radula, 222
Cymbium, 255, 367, 425; radula, 221
Cymbulia, 437
Cymbuliopsis, 437
Cynodonta, 424
Cyphoma, 419
Cypraea, 178, 419; prices given for
rare, 122; mantle-lobes, 177, 178;
radula, 224; shell, 255, 260, 261; C.
moneta, 96
Cypraecassis, 420
Cypraedia, 419
Cypraeovula, 419
Cyprimeria, 454
Cyprina, 451
Cyrena, 15, 453 ; distribution, 285, 294
Cyrenella, 453
INDEX
519
Cyrtia, 505; stratigraphical distribu- | Diloma, 408
tion, 507, 508
Cyrtoceras, 394
Cyrtodaria, 457
Cyrtodonta, 452
Cyrtolites, 407
Cyrtonotus, 448
Cyrtotoma, 414
Cysticopsis, 346-351, 441
Cystiscus, 425
Cystopelta, 325, 326, 440
Cytherea, 454, 454
DACRYDIUM, 449
Daedalochila, 441
Dall, W. H., quoted, 35; on branchiae,
164
Damayantia, 440
Daphnella, 426
Darbyshire, R. D., on tenacity of life,
39
Dardania, 415
Dart-sac, 142
Daudebardia, 289, 292 f., 440
Dawidsonia, 505, 508
Dawsonella, 410
Dayia, 505, 508
Decapoda, 384 f.
Decollation, 260
Deep-sea Mollusca, 374
De Folin, experiment on Cyclostoma,
157
Deianira, 410
Delage, experiments on otocysts, 197
Delphinula, 409
Deltidium, 499
Dendronotus, 433; protective colora-
tion, 72; habits, 51
Dentalium, 6, 444, 445 ; used as money,
97 ; veliger, 181; raduia, 228
Dimorphoptychia, 410
Dimya, 450
Dinobolus, 504, 508
Dinoplax, 403
Ditocardia, 9, 170, 405 f.
Diplodonta, 452
Diplommatina, 302-827, 413
Diplomphalus, 522, 323, 440
Diplopoma, 346, 351, 414
Dipsaccus, 424
Dipsas, 807
Discina, 464, 468, 471, 475, 487; distri-
bution, 485; fossil, 495, 504; strati-
graphical distribution, 506, 508
Discinidae, 487, 496, 504, 508, 511
Discinisca, 487, 510 ; distribution, 485,
486
Discites, 395
Discodoris, 434
Discosorus, 394
Distortio, 255 —see Persona
Ditropis, 312, 314, 414
Docoglossa, 227, 405
| Dolabella, 428, 431
Dolabrifer, 451
Dolium, 419; acid secretion, 237
Donaz, 269, 446, 453
Dondersia, 404
Dorcasia, 3335, 441
Doridium, 430
Doridunculus, 434; radula, 229
Doriopsis, 434
| Doris, breathing organs, 159; radula,
Dentellaria, 350-355, 441 ; aperture, 63 |
Desert species, 25, 85
Deshayesia, 411
Desmoulea, 423
Development of fertilised ovum. 150 f.
Dexiobranchaea, 437
Diadema, 414
Diala, 415
Dialeuca, 441
Diaphora, 314
Diaphorostoma, 412
Diastema, 418
Diastoma, 417
Diaulula, 434
Dibaphus, 425
Dibranchiata, 380; eye, 183; nervous
system, 207
Diceras, 269, 455
Didaena, 12; 291, 755
Differences of sex, 133
Dignomia, 511
Digonopora, 154, 144
230
Dorsanum, 423
Dosidicus, 390
Dosinia, 454
Doto, 433; protective coloration, 71
Dreissensia, 14, 128, 452 ; hibernation,
26; singular habitat, 48; veliger,
132, 146; eyes, 192
Dreissensiomya, 452
Drepania, 434
Drillia, 426
Drymaeus, 356, 442
Dryptus, 356, 441
Durgella, 301, 804, 440
Dwarf varieties, 88
Dybowskia, 290
EASTONIA, 454
Eburna, 267, 424; radula, 220
Ecardines, 466; muscles, 476; fossil,
493 ; families, 487, 503, 508
Eccyliomphalus, 413
Echinospira, 133
Edentulina, 38
Egg-laying of Arion, 42 f.; of Mollusca
generally, 123
Eglisia, 411
Eider-duck, shells used by, 102
520
Elaea, 322, 440
Elasmoneura, 411
Eledone, 385, 385; radula, 236
Elizia, 456
Elysia, 432 ; protective coloration, 73 ;
breathing, 152 ; radula, 217, 2380, 432
Emarginula, 265, 406
Embletonia, 429
Emmericia, 415
Ena, 296, 442
Enaeta, 425
Endoceras, 394
Endodonta, 325, 334, 441
Engina, 424
Enida, 408
Ennea, 298, 302, 306, 309, 314, 316,
328-337, 440, 440; habits, 54; Z£.
bicolor, 279
Enoplochiton, 408, 403
Enoploteuthis, 391
Ensis, 457
Entocolax, 77, 79, 152
Entoconcha, 77, 79, 152, 216
Entovalva, 77, 82
Ephippodonta, 453; commensal, 81
Epidromus, 420
Epiphragm, 26, 27 f.
Epipodia, 427
Erato, 419
Eremophila, 294
Ergaea, 248, 412
Erinna, 327, 439
Erosion, 276
Ervilia, 454
Erycina, 453
Escargotiéres, 119
Estria, 829, 440
Estuarine species, 14
Ethalia, 409
Eucalodium, 260, 353, 442
Euchelus, 408
Euchrysallis, 420
Eudioptus, 442
Eudoxochiton, 403
Euhadra, 316, 318, 447
Eulamellibranchiata, 451; gill, 166,
167
Eulima, 422; parasitic, 77, 79
Eulimella, 250, 422
Eulota, 296, 441
Euomphalus, 247, 413
Euplecta, 440
Eupleura, 423
Euplocamus, 434
Eurybia, 438
Eurycampta, 346-351
Eurycratera, 349, 351, 441
Eurystoma, 304
Eurytus, 442
Euthria, 424
Euthyneura, 203
Eutrochatella, 347-351, 348, 410
MOLLUSCA — BRACHIOPODA
| Exploring expeditions, 362
Eye in Mollusca, 181 f.
FACELINA, 432
Fasciolaria, 424; radula, 221
Fastigiella, 416
Favorinus, 432
Fenella, 415
Fertilised ovum, development, 130 f.
| Ferussacia, 291, 298, 297 f., 442
Fiji islanders, use of shells, 98
Filibranchiata, 448 ; gill, 166
Fiona, 432; radula, 217
Firoloida, 421
Fischer and Bouvier, on breathing of
Ampullaria, 158
Fischeria, 15, 3828, 453
Fish devour Mollusca, 59
Fissurella, 265, 406 ; breathing organs,
153; apical hole, 156; nervous sys-
tem, 204; radula, 227 ; growth, 261
Fissurellidaea, 406
Fissuridea, 406
Fissurisepta, 406
Fistulana, 262, 457
Flabellina, 432
Fluminicola, 415
Folinia, 415 :
Food of Mollusca, 30 f. ; Mollusca as
food, 102 f.
Foot, 198 ; in classification, 5
Forel, on deep-water Limnaea, 162
Formation of shell, 255
Fortisia, 429
Fossarina, 413
Fossarulus, 302, 415
Fossarus, 413
Fourth orifice in mantle, 174
Fresh-water species living in sea, 12;
frozen hard, 24
Frogs and toads devour Mollusca, 58
Fruticicola, 285, 290, 316, 318, 447
Fruticocampylaea, 296
Fryeria, 434
| Fulgur, 249, 424
| Fusispira, 420
Fusus, 262, 424
GADINTIA, 152, 431; breathing, 18, 151;
classification, 19; radula, 217, 230
Gain, W. A., quoted, 32, 33, 39; on
taste of Mollusca, 179
Galatea, 15, 328, 336, 453
Galeomma, 175, 453
Galerus, 248, 412; egg-capsules, 125
Garstang, W., on protective and warn-
ing coloration, 73
_Gaskoin, on tenacity of life, 38; on
egg-laying, 42
Gassies, on hybrid union in snails, 130
_Gasteropoda, on classification, 8, 11,
|; 400 f.
INDEX
Gastrana, 453
Gastrochaena, 457 ; habits, 64
Gastrodonta, 440
Gastropteron, 245, 430
Gaza, 376, 408
Gena, 246, 408
Genea, 424
Genotia, 426
Geomalacus, 160, 288, 291, 441; pro-
tective coloration, 70
Geomelania, 16, 348, 351, 474
Georgia, 331, 414
Georissa, 318, 410
Geostilbia, 338, 442
Gerontia, 441
Gerstfeldtia, 290
Gibbula, 408
Gibbus, 328-338, 440, 440
Gillia, 415
Gills — see Branchiae
Girasia, 301, 3804, 440
Glandina, 54, 178, 278, 292 f., 339-
355, 440 ; radula, 231, 232 ; habits, 53
Glands, germ, 134, 140; nidamental,
136
Glassia, 501, 505
Glaucomya, 320, 454
Glaucus, 429, 432
Gleba, 437
Glessula, 301, 309, 310, 3538, 442
Glochidium, 147
Glomus, 448
Glossoceras, 394
Glossophora, 7
Glottidia, distribution, 485, 487
Glycimeris, 457
Glyphis, 406
Glyptostoma, 341, 441
Gomphoceras, 394, 395
Gonatus, 391
Goniatites, 397, 398
Goniobasis, 341, 417
Goniodoris, 434; protective colora-
tion, 73; radula, 229
Goniomya, 458
Gonostoma, 291, 316, 441
Goniostomus, 442
Grammysia, 459
Grateloupia, 454
Great Eastern and mussels, 116
Greenhouses, slugs in, 35
Green oysters, 108
Gresslya, 458
Growth of shell, 40, 257
Guesteria, 440
Guildfordia, 409
Guivillea, 186, 376, 425
Gulls and Mollusca, 56
Gundlachia, 19, 325, 345, 352, 359,
439
Gymnoglossa, 216, 225, 422
Gymnosomata, 437
521
Gyroceras, 247, 395
Gyrotoma, 417
HADRA, 306, 315, 319-825, 322, 447
Hadriania, 423
Haemoglobin, 171
Hainesia, 336, 414
Halia, 366, 426
Haliotinella, 431
Haliotis, 266, 407; and coyote, 57;
holes of, 156; osphradium, 195;
epipodium, 199; nervous system,
204; radula, 215, 226
Halopsyche, 159, 488, 438
Haminea, 428, 430; protective colora-
tion, 73
Hamites, 399
Hamulina, 399
Hanleyia, 403
Hapatlus, 331, 442
Harpa, radula, 425, 216, 221; self-
mutilation, 45
Harpagodes, 418
Harpoceras, 399
Harvella, 454
Hatching of eggs, 43
Hazay, on duration of life, 39; on
variation in Limnaea, 93
Hearing powers of Mollusca, 196
Heart, in classification, 9 ; action during
hibernation, 26 ; and branchiae, 169
Hectocotylus arm, 157 f.
Helcion, 405 ; protective coloration, 69
Helcioniscus, 405
Hele, F. M., on Hyalinia, 33; on
Stenogyra, 34
Helicarion, 309, 316, 325, 3382, 440;
radula, 232; habits, 45, 67
Helicidae, radula, 232, 234
Helicina, 305, 306, 316-827, 388-858,
410; origin, 21; exterminated by
cold, 24
Helicophanta, 335, 386, 441, 441
Heligmus, 449
Helix, 441; toothed aperture, 63 ; pro-
tective coloration, 70 ; variation, 87;
carbonic acid, 163; eye, 181, 183;
food, 179; smell, 194; jaw, 211; dis-
tribution, 285; tenacity of life, 37;
breeding, 129
Helix alternata, 340; angulata, 350;
aperta, 38, 39, 51, 293; arbustorum,
bathing, 23 ; caperata, variation, 89 ;
cereolus, 840 ; cicatricosa, 316 ; creni-
labris, 45 ; delphinuloides, 297 ; deser-
torum, 37, 38, 70, 294; jidelis, 341;
haemastoma, habits, 70; harpa, 287 ;
hortensis, 10, 279; pulsations, 26;
epiphragm, 28 ; rock-boring, 49 ; dart,
143 ; imperator, 347; habits, 45;
laciniosa, 297; lactea, 25, 38, 42, 279;
lima, 350 ; muscarum, 347; nemoralis,
522
38, 180; niciensis, 292; nux denticu-
lata, 350; palliata, 340; pisana, 25;
habits, 33 ; pomatia, 25, 34, 40; eye,
181; pomum, 322; pulchella, 279;
richmondiana, 322; rosacea, 259;
rostrata, 347; rota, 314; rufescens,
pulsations, 26; similaris, 279; sou-
verbiana, 336, 441; strigata, 293;
tristis, habits, 49; turricula, 297;
Veatchii, 38; Waltoni, 304; Wollas-
toni, 297 ; zonata, 298
Helix aspersa, homing, 35; smell, 36 ;
duration of life, 39; growth, 40;
strength, 45 ; boring rock, 50; varia-
tion, 87, 89; eaten, 119; hybrid
union, 130 ; generative organs, 140 f.,
141; dart-sac, 143 ; pulmonary cham-
ber, 160; radula, 217; alimentary
canal, 237; monstrosities, 251, 252;
growth, 258 ; distribution, 279, 289
Hemiarthrum, 403
Hemicardium, 455
Hemidonax, 453
Hemifusus, 424
Hemipecten, 450
Hemiplecta, 310, 316, 319, 321, 440
Hemisepius, 389
Hemisinus, 357, 417
Hemiitoma, 265
Hemitrichia, 314
Hemitrochus, 346-351, 441
Hemphillia, 245, 341, 441
Hercoceras, 395
Herdman, Prof. W. A., on cerata of
Nudibranchs, 71 f.; experiments on
taste of Nudibranchs, 72; on Lit-
torina rudis, 151 n.
Hermaea, 432; protective coloration,
73
Hermaphrodite Mollusca, 184, 140, 145
Hermit-crabs, shells used by, 102
Hero, 432
Heterocardia, 454
Heterodiceras, 455
Heteropoda, 9, 420 f.; radula, 228;
foot, 200
Heudeia, 316, 410
Hexabranchus, 434
Hibernation, 25, 163
High altitudes, Mollusca living at, 24
Himella, 15
Hindsia, 424
Hindsiella, 453
Hinge area, 493, 498
Hinge, in bivalves, 272
Hinnites, 257, 450
Hipponyx, 248, 412
Hippopus, 455
Hippurites, 455, 456
Histiopsis, 391
Histioteuthis, 391
Holcostoma, 417
MOLLUSCA — BRACHIOPODA
Holohepatica, 433
Holopella, 411
Holospira, 339, 355, 442
Holostomata, 156
Homalogyra, 413; radula, 223
Homalonyx, 245, 3438-358, 443
Homing powers of Mollusca, 34
Homorus, 3380-837, 443
Hoplites, 399
Hoplopteron, 422
Horea, 332
Horiostoma, 409
Hot springs, Mollusca living in, 25
Huronia, 394
Hyalaea, 10, 436
Hyalimax, 245, 305, 306, 3388, 443
Hyaline stylet, 240
Hyalinia, 440; pulsations, 26; food,
33; smell, 194; dart, 143; radula,
232, 234; distribution, 287 f., 318,
340-357 ; H. alliaria, 279; smell,
194; cellaria, 279; Draparnaldi, 33
Hyalocylix, 437
Hyalosagda, 352
Hybocystis, 305,309, 414
Hybridism, 129
Hydatina, 430; radula, 231
Hydrobia, 325, 382, 415; H. ulvae,
egg-laying, 128
Hydrocena, 298, 410; radula, 226
Hymenoptera build in dead shells, 102
Hypobranchaea, 434; radula, 230
Hypotrema, 448
Hypselostoma, 248, 302, 305, 514, 442
Hyria, 344, 452
Hystricella, 297
IANTHINA, 360, 126, 411; egg-cap-
sules, 125; eyes, 186; radula, 224
LIapetella, 385
Iberus, 285-293, 297, 441
Ichthyosarcolites, 456
Idalia, 179, 429, 434; radula, 229, 280
Idas, 449
Idiosepion, 389
Illex, 390
Imbricaria, 425; radula, 221
Imperator, 409
Indians of America, use of shells, 100
Infundibulum, 408
Inioteuthis, 889
Ink-sac, 241
Inoceramus, 449
Insects eaten by Mollusca, 82
Insularia, 319, 320
Intestine, 241
Io, 16, 340, 417
Topas, 423
Iphigenia, 16, 453
Travadia, 305, 415
Tridina, 294
TIrus, 297
INDEX
523
Jsanda, 409
Ischnochiton, 403
Tsidora, 298, 320-827, 333, 356, 359,
439
Ismenia, 404
Tsocardia, 269, 451, 451
TIsodonta, 453
Isomeria, 345, 356, 441
Issa, 434
JAMAICIA, 414
Janella, 161, 443; pulmonary orifice,
161
Janellidae, radula, 284; distribution,
321-326
Janus, 432
Japonia, 318
Jaws, 210
Jeanerettia, 346-851, 441
Jeffreys, Dr., on Limnaea,
Neptunea, 193
Jeffreysia, 415; radula, 223
Jorunna, protective coloration, 75
Jouannettia, 457
Jullienia, 307, 415
Jumala, 424
KALIELLA, 301, 304, 810, 314-517,
335, 440
Kalinga, 434
Kashmir, land Mollusca, 280
Katherina, 403
Kelletia, 424
Kellia, 453
Kellyella, 452
Kidneys, 242
King, R. L., on smell in bivalves, 195
Kingena, 506, 508
Kitchen-middens, 104
Koninckella, 505 ; stratigraphical dis-
tribution, 507, 508
Koninckina, 505; stratigraphical dis-
tribution, 507, 508
Koninckinidae, 501, 505, 508
Kutorgina, 504; stratigraphical distri-
bution, 506, 508; embryonic shell,
509
LABIAL palps, 210
Labyrinthus, 342, 353-357, 441; aper-
ture, 63
Lacaze-Duthiers on Testacella, 52 f.;
on smell in Helix, 194
Lacuna, 413
Lacunopsis, 352
Lagena, 424
Lagochilus, 309, 316-519, 414
Lamellaria, 245, 411; habits and pro-
tective coloration, 74; parasitic, 78 ;
radula, 223
Lamellidoris, 434; radula, 229, 230, 231
Lampania, 417
Land Mollusca, origin, 11 f.
Lanistes, 249, 294, 528, 331, 416
Lankester, Prof. E. Ray, on shell-
gland, 132 ; on haemoglobin, 171
Lantzia, 278, 338, 439
Laoma, 441
Larina, 302, 417
Larvae of Pelecypoda, 7; of insects
resembling Mollusca, 67 f.
Lasaea, 453
Latia, 19, 326, 439
Latiaxis, 423
Latirus, 424
Latter, O. H., on Glochidium, 147
Layard, E. L., on self-burying Mol-
lusca, 41; on sudden appearance of
Stenogyra, 47; on Coeliaxis, 49 ; on
Rhytida and Aerope, 54
| Leda, 447
34; on |
| Leila, 344, 452
| Leonia, 414
Leia, 348-551, 442
Lepeta, 405
Lepetella, 405
Lepetidae, radula, 227
Lepidomenia, 404; radula, 229
Leptachatina, 327
Leptaena, 500, 501, 502, 503, 505;
stratigraphical distribution, 507, 508
Leptaxis, 441
Leptinaria, 357, 358, 442
Leptochiton, 403
Leptoconchus, 75, 423
Leptoloma, 348, 351
Lepton, 453; parasitic, 77 ; commen-
sal, 80; mantle-edge, 175, 178
Leptoplax, 403
Leptopoma, 316, 319, 338, 414
Leptoteuthis, 390
Leptothyra, 409
Leroya, 331
Leucochila, 442
Leucochloridium, 61
Leucochroa, 292, 295, 441
Leuconia, 439
Leucotaenta, 335, 359, 441
Leucozonia, 64, 424, 424
Levantina, 295
Libania, 295
Libera, 327, 441; egg-laying, 128
Libitina, 451
Licina, 414
Life, duration of, in snails, 39
Ligament, 271
Liguus, 349, 351, 442
Lima, 178, 179, 450; habits, 63
Limacidae, radula, 232
Limacina, 59, 249, 486, 436
Limapontia, 429, 432; breathing, 152
Limax, 245, 440; food, 31, 179 ; varia-
tion, 86; pulmonary orifice, 160; shell,
175 ; jaw, 211 ; radula, 217 ; distribu-
524
tion, 285, 324; L. agrestis, eats May
flies, 31; arborum, slime, 50; food,
31; flavus, food, 33, 36; habits, 35,
36 ; gagates, 279, 358 ; maximus, 32,
161 ; eats raw beef, 32 ; cannibalism,
32; sexual union, 128; smell, 195 f.
Limea, 450
Limicolaria, 329-332, 443
Limnaea, 439; self-impregnation, 44 ;
development and variation, 84, 92, 95;
size affected by volume of water, 94;
eggs, 124; sexual union, 154; jaw,
211; radula, 217,235; L. awricularia,
24; glutinosa, sudden appearance, 46;
Hookeri, 25 ; involuta, 82, 278, 287 ;
peregra, 10,180; burial, 27; food, 54,
37; variation, 85; distribution, 282 ;
palustris, distribution, 282; stagnalis,
food, 34, 37; variation, 85, 95; cir-
cum-oral lobes, 131; generative or-
gans, 414; breathing, 161; nervous
system, 204 ; distribution, 282 ; trun-
catula, parasite, 61; distribution, 282
Limnocardium, 455
Limnotrochus, 332, 415
Limopsis, 448
Limpet-shaped shells, 244
Limpets as food for birds, 56 ; rats, 57 ;
birds and rats caught by, 57; as
bait, 118
Lingula, 464, 467, 468, 471, 472, 475,
475, 477, 478, 487; habits, 483, 484 ;
distribution, 485; fossil, 493, 494,
503; stratigraphical distribution,
506, 508, 510, 511
Lingulelia, 493, 503; stratigraphical
distribution, 506, 508, 511
Lingulepis, 503, 511
Lingulidae, 485, 487, 496, 503, 508
Linnarssonia, 504 ; stratigraphical dis-
tribution, 506, 508
Lintricula, 426
Liobaikalia, 290
Liomesus, 424
Lioplax, 340, 416
Liostoma, 424
Liostracus, 442
Liotia, 408 .
Liparus, 324, 359, 441
Lissoceras, 399
Lithasia, 340, 417
Lithidion, 414
Lithocardium, 455
Lithodomus, 449
Lithoglyphus, 294, 296, 297, 415
Lithopoma, 409
Lithotis, 302, 443
Litiopa, 30, 361, 415
Littorina, 413 ; living out of water, 20;
radula, 20,215; habits, 50; protective
coloration, 69; egg-laying, 126; hybrid
union, 130; monstrosity, 251, 252;
MOLLUSCA — BRACHIOPODA
operculum, 269 ; erosion, 276; L. lit-
torea, in America, 374 ; obtusata, gen-
erative organs, 185; rudis, 150; Prof.
Herdman’s experiments on, 151 n.
Littorinida, 415
Lituites, 247, 395
Liver, 239 ; liver-fluke, 61
Livinhacea, 333, 359, 441
Livona, 408 ; radula, 226 ; operculum,
268
Lloyd, W. A., on Nassa, 198
Lobiger, 432
Lobites, 397
Loligo, 578-389 ; glands, 186 ; modified
arm, 139; eye, 188; radula, 236;
club, 381; L. punctata, egg-laying,
127 ; vulgaris, larva, 153
Loligopsis, 391
Loliguneula, 390
Loliolus, 390
Lomanotus, 433
Lophocercus, 432
Lorica, 403
Lowe, E. J., on growth of shell, 40
Loxonema, 417
Lucapina, 406
Lucapinella, 406 -
Lucerna, 441
Lucidella, 348-351, 410
Lucina, 270, 452
Lucinopsis, 454
Lung, 151, 160
Lunulicardium, 455
Lutetia, 452
Lutraria, 446, 456
| Lychnus, 442
Lyonsia, 458
Lyonsiella, 458 ; branchiae, 168
Lyra, stratigraphical distribution, 507
Lyria, 425
Lyrodesma, 447
Lysinoe, 441
Lytoceras, 398
MAACKTA, 290
Macgillivrayia, 183
Machomya, 458
Maclurea, 410
Macroceramus, 348-353, 442
Macroceras, 440
Macrochilus, 417
Macrochlamys, 296, 299, 301 f., 510,
316-322, 440
Macrocyclis, 558, 359, £442
Macron, 424
Macroon, 441
Macroscaphites, 247, 399, 399
Macroschisma, 265, 406
Mactra, 271, 446, 454
Macularia, 285, 291, 292 f., 441
Magas, 506; stratigraphical distribu-
tion, 507, 508
eee ee
INDEX
Magellania, 500
Magilus, 75, 423
Mainwaringia, 302
Malaptera, 418
Malea, 419
Malletia, 447
Malleus, 449
Mangilia, 426
Mantle, 172 f., 173; lobes of, 177
Margarita, 408; radula, 225
Marginella, 425; radula, 221
Mariaella, 514, 3388, 440
Marionia, 433
Marmorostoma, 409
Marrat, F. P., views on variation, 82
Marsenia, 135
Marsenina, 411
Martesia, 305, 457
Mastigoteuthis, 390
Mastus, 296, 442
Matheronia, 455
Mathilda, 250, 417
Maugeria, 403
Mazzalina, 424
Megalatractus, 424
Megalodontidae, 457
Megalomastoma, 544, 414
Megalomphalus, 416
Megaspira, 358, 442
Megatebennus, 406
Megerlia, distribution, 486, 487
Meladomus, 249, 328, 331, 416
Melampus, 18, 199, 250, 489, 439
Melanatria, 336
Melania, 276, 417, 417; distribution,
285, 292 f., 316 f., 324, 336
Melaniella, 442
Melaniidae, origin, 17
Melanism in Mollusca, 85
Melanopsis, 417; distribution, 285,
291, 292 f., 323, 326
Melantho, 340, 416
Melapium, 424
Meleagrina, 449
Melia, 348
Melibe, 432
Melongena, 424 ; radula, 220 ; stomach,
238
Merica, 426
Merista, 505, 508
Meroe, 454
Merope, 327
Mesalia, 417
Mesembrinus, 356, 442
Mesodesma, 454
Mesodon, 340, 441
Mesomphix, 340, 440 ‘
Mesorhytis, 377
Meta, 423
Metula, 424
Meyeria, 424
Miamira, 434
525
Microcystis, 825, 524, 327, 338, 440
Microgaza, 408
Micromelania, 12, 297
Microphysa, protective habits, 70
Microplax, 403
Micropyrgus, 415
Microvoluta, 425
Middendorfiia, 403
Milneria, 451
Mimicry, 66
Minolia, 408
Mitra, 425; radula, 221
Mitrella, 423
Mitreola, 425
Mitrularia, 248, 412
Modiola, 446, 449; habits, 64 ; genital
orifice, 242
Modiolarca, 449
Modiolaria, 449; habits, 78
Modiolopsis, 452
Modulus, 417
Monilia, 408
Monkey devouring oysters, 59
Monoceros, 423
Monocondylaea, 452
Monodacna, 12, 297, 456
Monodonta, 408, 408 ; tentaculae, 178
Monogonopora, 154, 140
Monomerella, 496, 504
Monopleura, 456
Monotis, 449
Monotocardia, 9, 170, 417
Monstrosities, 250
Montacuta, 452; M. ferruginosa, com-
mensal, 80; substriata, parasitic, 77
Mopalia, 403
Moquin-Tandon, on breathing of Lim-
naeidae, 162; on smell, 198 f.
Moreletia, 440
Morio, 420
Mormus, 356, 442
Moseley, H. N., on eyes of Chiton, 187 f.
Moussonia, 327
Mouth, 209
Mucronalia, 422
Mucus, use of, 63
Mulinia, 272
Miilleria, 344, 452
Mumiola, 422
Murchisonia, 265, 407
Murchisoniella, 422
Murex, 423; attacks Arca, 60; use of
spines, 64; egg-capsules, 124; eye,
182; radula, 220; shell, 256
Musical sounds, 50
Mussels, cultivation of, 115; as bait,
116 ; poisonous, 117 ; on Great East-
ern, 116
Mutela, 294, 328, 331, 336, 452
Mutyca, 425
Mya, 271, 275, 446, 456; stylet, 240;
M. arenaria, variation, 84
526
Myacea, 456
Myalina, 449
Mycetopus, 307, 316, 344, 452
Myochama, 458
Myodora, 458
Myophoria, 448
Myopsidae, 389
Myrina, 449
Myristica, 424
Mytilacea, 448
Mytilimeria, 458
Mytilops, 452
Mytilopsis, 14
Mytilus, 258, 449; gill filaments, 166,
285; M. edulis, 14, 165.; attached to
crabs, 48, 78; pierced by Purpura,
60; Bideford Bridge and, 117; rate
of growth, 258 ; stylet, 240
Myxostoma, 414
NACELLA, 405
Naiadina, 449
Nanina, 278, 300 f., 835, 440 ; radula,
217, 232
Napaeus, 296-299, 316, 442
Naranio, 454
Narica, 412
Nassa, 428; egg-capsules, 126 ; sense
of smell, 198
Nassodonta, 423
Nassopsis, 352
Natica, 246, 263, 411; spawn, 126;
operculum, 268
Naticopsis, 409
‘Native’ oysters, 106
Nausitora, 15
Nautiloidea, 393
Nautilus, 254, 392, 395; modified arms,
140 ; eye, 183 ; nervous system, 206 ;
radula, 236; kidneys, 242
Navicella, 267, 268, 324, 327, 410;
origin, 17
Navicula, 358, 442
Navicula (Diatom), cause of greening
in oysters, 108
Nectoteuthis, 389
Neda, 431
Nematurella, 12, 297
Nembrotha, 434
Neobolus, 504
Neobuccinum, 424
Neocyclotus, 357, 358
Neomenia, 8, 133, 216, 228, 404, 404 ;
breathing organs, 154; nervous sys-
tem, 203
Neothauma, 332
Neotremata, 511
Neptunea, 252, 262, 423 ; egg-capsules,
126 ; capture, 193 ; monstrosity, 251
Nerinea, 417
Nerita, 17, 410; N. polita used as
money, 97
MOLLUSCA — BRACHIOPODA
Neritidae, 260, 470; radula, 226
Neritina, 256, 410; origin, 16, 17, 21;
egg-laying, 128; eye, 181; distribu-
tion, 285, 291 f., 324, 827; N. fluvia-
tilis, habitat, 12, 25
Neritoma, 410
Neritopsis, 409; radula, 226; opercu-
lum, 269
Nervous system, 201 f.
Nestotis, 357, 442
New Zealanders, use of shells, 99
Nicida, 413
Ninella, 409
Niphonia, 408
Niso, 422
Nitidella, 423
Nodulus, 415
Notarchus, 431
Nothus, 358, 442
Notobranchaea, 438
Notodoris, 434
Notoplax, 403
Novaculina, 805
Nucula, 254, 269, 2738, 447
Nuculidae, otocyst, 197 ; foot, 201
Nuculina, 448
Nudibranchiata, 432; defined, 10 ; pro-
tective and warning colours, 71 f.;
breathing organs, 159
Nummutlina, 295
Nuttallina, 403
OBBA, 3811, 315, 441
Obbina, 806, 311, 312, 314, 319
Obeliscus, 442
Obolella, 496, 504; stratigraphical dis-
tribution, 506, 508
Obolidae, 496, 504, 508
Obolus, 504, 508; embryonic shell, 509
Ocinebra, 423
Octopodidae, hectocotylised arm, 137,
159, 140
Octopus, 879-386 ; egg-capsules, 127;
vision, 184; radula, 236 ; crop, 238
Ocythoe, 384; hectocotylus, 138
Odontomaria, 407
Odontostomus, 358, 442
Odostomia, 250, 422; parasitic, 78
Oesophagus, 237
Ohola, 434
Oigopsidae, 390
Oldhamina, 506, 508
Oleacina, habits, 55
Oliva, 199, 255, 275, 425, 426
Olivancillaria, 426
Olivella, 260, 267, 426; O. biplicata as
money, 97
Olivia, 408
Omalaxis, 413
Omalonyx, habitat, 23
Ommastrephes, 6, 378, 390
| Ommatophores, 180, 187
INDEX
Omphalotropis, 306, 309, 316, 324, 327,
338, 414
Onchidiella, 443
Onchidiidae, 245; radula, 234; anus,
241
Onchidiopsis, 411
Onchidium, 443 ; breathing, 163 ; eyes,
187
Onchidoris, radula, 250
Oniscia, 420
Onoba, 415
Onychia, 390
Onychoteuthis, 390; club, 386
Oocorys, 420
Oopelta, 329, 440
Opeas, 442
Operculum, 267 f.
Ophidioceras, 247, 395
Ophileta, 413
Opis, 451
Opisthobranchiata, 427; defined, 9;
warning, etc., colours, 71 f.; genera-
tive organs, 144; breathing organs,
158 ; organs of touch, 178; parapodia,
199 ; nervous system, 203 ; radula, 229
Opisthoporus, 266, 300, 514-316, 414
Opisthostoma, 248, 309, 413
Oppelia, 399
Orbicula, 464
Orbiculoidea, 504, 510
Orders of Mollusca, 5-7
Organs of sense, 177
Origin of land Mollusca, 11 f.
Ornithochiton, 403
Orphnus, 356, 441
Orpiella, 440
Orthalicus, 342-358, 355, 442; habits,
27 ; variation, 87; jaw, 211; radula,
233, 234
Orthis, 505; stratigraphical distribu-
tion, 506, 507, 511
Orthoceras, 394,
Orthonota, 457
Orthothetes, 505; stratigraphical dis-
tribution, 507, 508
Orygoceras, 247
Osphradium, 194 f.
Ostodes, 327
Ostracotheres, 62
Ostrea, 252, 258, 446, 449; intestine, 241
Otina, 18, 439
Otoconcha, 326, 440
Otocysts, 196 f., 197
Otopleura, 422
Otopoma, 331, 338, 414
Otostomus, 353, 442 ;
Ovary, 135
Ovoviviparous genera, 123
Ovula, 419; protective coloration, 70,
75 ; radula, 80, 224; used as money, 97
Ovum, development of fertilised, 150
Oxychona, 358
I94
527
Oxygyrus, 422; foot, 200
Oxynoe, 432; radula, 230
Oyster-catchers, shells used by, 102
Oyster, cultivation, 104-109; living
out of water, 110; enemies, 110 f.;
reproduction, 112 f.; growth, 114,
cookery, 114; poisonous oysters,
114 ; vision, 190
PACHNODUS, 329-335, 441, 442
Pachybathron, 425
Pachychilus, 354
Pachydesma_ crassatelloides,
made from, 97
Pachydomidae, 451
Pachydrobia, 807, 415
Pachylabra, 416
Pachyotus, 354, 386, 355, 358, 447
Pachypoma, 409
Pachystyla, 3387, 440
Pachytypus, 451
Padollus, 407
Palaearctic region, 284 f.
Palaeoneilo, 447
Palaeosolen, 457
Palaina, 327, 413
Palio, 434
Pallial line and sinus, 270
Pallifera, 540, 440
Palliobranchiata, 464
Paludina, 416; penis, 136; eye, 181,
vision, 184; P. vivipara, 24—see
also Vivipara
Paludomus, 332, 336, 3888, 417
Panama, Mollusca of, 3
Panda, 322, 325, 385
money
| Pandora, 458
Papuans, use of shells, 99
Papuina, 809, 319-324, 441
Paramelania, 382
Paramenia, 404
| Parasitic worms, 60 f. ; Mollusca, 74 f.
Parastarte, 451
Parkinsonia, 398
Parmacella, 245, 291, 294 f., 438 n.,
440; radula, 232; shell, 175
Parmacochlea, 322, 326, 440
Parmarion, 309, 440
Parmella, 326, 440
Parmophorus, 406
Parthena, 349-352, 350, 441
Parts of univalve shell, 262; bivalve,
269
Partula, 519-527, 326, 442; radula, 2383
Paryphanta, 321, 825, 440
Paryphostoma, 416
Passamaiella, 332
Patella, 405, 464; as food, 56 f.; eye,
182; radula, 214, 215, 227; crop, 288;
anus, 241; kidneys, 242; shell, 262 ;
P. vulgata, veliger, 132; breathing
organs, etc., 156, 157
528
MOLLUSCA — BRACHIOPODA
Patelliform shell in various genera, 19
Paterina, 509, 510, 511
Patinella, radula, 227
Patula, 297, 298, 318-358, 340, 447
Paxillus, 413
Pearl oysters, 100
Pecten, 446, 450, 450 ; organs of touch, |
178 ; ocelli, 191 ; flight, 192 ; nervous
system, 206; genital orifice, 242;
ligament, 271
Pectinodonta, 405; radula, 227
Pectunculus, 448
Pedicularia, 75, 419; radula, 224
Pedinogyra, 319, 322, 442
Pedipes, 18, 199, 489, 439
Pedum, 450
Pelagic Mollusca, 360
Pelecypoda, 7, 445 ; development, 145 ;
generative organs, 145; branchiae,
166-169 ; organs of touch, 178 ; eyes,
189 f.; foot, 201; nervous system, 205
Pella, 355
Pellicula, 352, 442
Peltoceras, 399
Pentadactylus, 423
Peraclis, 436
Pereiraea, 418
Perideris, 328-330, 443
Periodicity in breeding, 129
Periophthalmus, 187
Periostracum, 275
Periploma, 459
Perisphinctes, 399
Perissodonta, 418
Perissolax, 424
Peristernia, 424
Perna, 449; ligament, 271
Pernostrea, 449
Peronaeus, 358, 442
Peronia, 443
Perrieria, 319, 442
Perrinia, 408
Persicula, 425
Persona (= Distortio), 420
Petenia, 355, 440
Petersia, 420
Petraeus, 295, 831, 442
Petricola, 454
Phacellopleura, 403
Phanerophthalmus, 430
Phaneta, 408
Phania, 312, 441
Pharella, 457
Pharus, 457
Pharynx, 210
Phasianella, 409
Phasis, 333
Phenomena of distribution, 362
Philine, 245, 428, 430;
coloration, 73; radula, 229, 230
Philomycus, 245, 318, 440
Philonexis, 188
protective |
Philopotamis, 304, 417
Phoenicobius, 315, 441
Pholadacea, 457
Pholadidea, 457
| Pholadomya, 459
Pholas, 245, 274, 447, 457; in fresh
water, 15
Phos, 424
Photinula, 408
Phragmophora, 386
Phyllidia, 434; breathing organs, 159
Phyllirrhoe, 360, 428, 433
Phyllobranchus, 432
Phylloceras, 398, 398 ; suture, 396
Phylloteuthis, 390
Physa, 439; aestivating out of water,
27; spinning threads, 29; sudden
appearance, 46; osphradium, 195 ;
nervous system, 205; radula, 235;
P. hypnorum, 23, 27
Pileolus, 410
| Pileopsis, 76
Piloceras, 394
| Pinaxia, 423
Pineria, 442
Pinna, 449; shell, 254
Pinnoctopus, 385
Pinnotheres, 62
Pinoceras, 398
Pirena, 417
Pirenella, 416
Piropsis, 424
Pirula —see Pyrula
Pisania, 424
Pisidium, 453; smell, 195; ova, 146;
P. pusillum, distribution, 282
Pitys, 327
Placobranchus, 432
Placostylus, 322, 323-825, 359, 442;
radula, 233
Placuna, 448; P. placenta used for
windows, 101
Placunanomia, £48
Placunopsis, 448
Plagioptycha, 847-851, 441
Plagioptychus, 456
Planaxis, 417
Planispira, 311, 812, 319, 441
Planorbis, 27, 247, 439; monstrosity,
93 ; eye, 181; P. albus, distribution,
282
Platyceras, 76, 412
Platydoris, 434
Platypoda, 471
Platyschisma, 413
Plaxiphora, 403
Plecochilus, 442
Plecotrema, 439
Plectambonites, 505
_ Plectomya, 459
| Plectopylis, 303, 805, 314, 316; aper-
ture, 63
INDEX
Plectostylus, 358, 442
Plectotropis, 305, 806, 310, 311, 314—
318, 441
Plectrophorus, 298
Plesiastarte, 451
Plesiotriton, 420
Pleurobranchaea, 431; jaws, 212
Pleurobranchoidea, 431
Pleurobranchus, 245, 428,
coloration, 73; jaws, 212; radula, 230
Pleurocera, 340, 417
Pleuroceridae, origin, 17
Pleurodonta, 348; aperture, 63
Pleuroleura, 433
Pleuromya, 458
Pleurophorus, 451
Pleurophyllidia, 433 ; breathing organs,
159; radula, 230
Pleuropyrgus, 357
Pleurotoma, 426, 426; slit, 2638, 265
Pleurotomaria, 266, 373, 376, 407, 407; |
| Protobranchiata, 447; branchiae, 166
_ Protoma, 417
| Protremata, 511
Pliny the elder, on use of snails, 118,120 |
prices given for recent, 122; slit, 156;
radula, 226
Plicatula, 450
Plocamopherus, 434
Plochelaea, 425
Plutonia, 298, 440
Pneumoderma, 158, 437, 438
Poecilozonites, 352, 440
Poisonous bite of Conus, 65; poison-
ous oysters, 114; mussels, 117
Polycera, 434; radula, 230
Polycerella, 434
Polyconites, 456
Polydontes, 346-351, 347, 441
Polygona, 424
Polygyra, 340, 345-353, 447 ; aperture,
63
Polygyratia, 246, 263, 357, 442
Polymita, 346- 351, 347, 44d
Polyplacophora, 9, 407 f.; radula, 228
Polytremaria, 266, 407
Pomatia, 285, 293, 295, 441
Pomatias, 288, 289, 292 f., 302, 413
Pomatiopsis, Gis
Pomaulaz, 409
Pompholyx, 250, 341, 439
Ponsonbya, 332
Poromya, 459; branchiae, 168°
Porphyrobaphe, 27, 356, 442
Position of Mollusca in Animal King-
dom, 4
Potamides, 16, 416
Potamomya, 15
Potamopyrgus, 325, 826, 415
Poterioceratidae, 394
Praecardium, 459
Prasina, 449
Prices given for rare shells, 121
Primitive mollusc, form of, 245; types
of, 7
WANT TYT
431; warning |
_ Prophysaon, 341, 441;
529
Prisogaster, 409
Pristiloma, 341, 440
_ Proboscidella, 497, 504
Productidae, 497, 500, 504, 508
Productus, 492, 501, 502, 504; strati-
graphical distribution, 508
Promachoteuthis, 389
Proneomenia, 404; breathing organs,
154 ; nervous system, 208 ; radula, 229
habits, 44
Propilidium, 405
Proserpina, 21, 355, 410
Proserpinella, 354, 410
Proserpinidae, relationships, 21
Prosobranchiata, 9, 404 f.; breathing
organs, 154
Prosocoelus, 451
_ Protective coloration, 69 f. ; in snails,
70; in Nudibranchs, 71 f. ; in other
Mollusca, 74
Protegulum, 509
Provocator, 376, 425
Psammobia, 456
Pseudachatina, 328-330, 443
Pseudedmondia, 452
Pseudobalea, 350
Pseudo-deltidium, 498, 511
Pseudodon, 295, 307, 452
Pseudolamellibranchiata, 167, 449
Pseudoliva, 424
Pseudomelania, 417
Pseudomilax, 296, 440
Pseudomurex, 423
Pseudopartula, 328
Pseudosubulina, 440
Ptenoglossa, 224, 411
Pterinaea, 449
Pteroceras, 256, 262, 418
Pteroctopus, 384
Pterocyclus, 266, 267, 300, 516, 414;
tube, 157
Pterodonta, 418
Pteropoda, 7, 434; breathing organs,
158 ; foot, 200; radula, 280
Pterotrachaea, 421; foot, 200; radula,
227
Ptychatractus, 424
Ptychoceras, 399
Ptychodesma, 452
Pugilina, 424
Pulmonata, 10, 22, 151, 185, 438; ori-
gin, 17, 19; breathing organs, 160;
nervous system, 203
Pulsellum, 444
Punctum, 441
Puncturella, 265, 406
Pupa, 289, 296, 325-357, 442; P. cine-
rea, hybrid union, 129
Pupidae, radula, 233
2M
530
Pupilla, 442
Pupillaea, 406
Pupina, 157, 266, 309, 318-327, 414
Pupinella, 318, 414
Purpura, 423; operctlum, 269; ero-
sion, 276; P. coronata, 367 ; lapillus,
feeding on Mytilus, 60; on oysters,
111; protective coloration, 69; vari-
ation, 90; egg-capsules, 124; time of
breeding, 129; distribution, 363 n.
Purpuroidea, 423
Pusionella, 426
Pygocardia, 451
Pygope, 497
Pyramidella, 422
Pyramidellidae, 262
Pyrazus, 50, 416
Pyrgina, 330
Pyrgula, 415
Pyrochilus, 441
Pyrolofusus, 423
Pyrula (= Pirula), 419, 420; spawn,
125; operculum, 269
Pythina, 453
QUENSTEDTIA, 456
Quoyia, 260, 417
RACHIGLOSSA, 220, 422; eggs, 124
Rachis, 329-335, 441, 442
Radiolites, 456
Radius, 419
Radsia, 403
Radula, 215 f.; of Littorina, 20; of
Cyclophorus, 21; of parasitic Mol-
lusca, 79
Raéta, 454
Ranella, 256, 420
Range of distribution, 362 f.
Rangia, 15, 453
Ranularia, 420
Rapa, 423
Rapana, 423
Raphaulus, 305, 309
Rathouisia, 316, 440
Rats devouring Mollusca, 57
Realia, 316, 327, 414
Recluzia, 411
Rectum, 241
Registoma, 414
Relationship of Mollusca to other
groups, 5
Renssoellaria, 512
Reproductive activity of oyster, 112;
system in Mollusca, 123, 134 f.
Requienia, 269, 455, 455
Respiration, 150 f.
Retzia, 508
Revoilia, 331, 414
Reymondia, 332
Rhabdoceras, 398
Rhagada, 311, 324
MOLLUSCA — BRACHIOPODA
Rhenea, 325, 440
Rhinobolus, 504
Rhiostoma, 247, 266, 3809, 414
Rhipidoglossa, 225, 405
Rhizochilus, 75, 423
Rhodea, 356, 441
Rhodina, 307, 310, 442
Rhynchonella, 466, 470, 471, 472, 474,
483, 487; distribution, 487 ; fossil,
492, 497, 499, 505; stratigraphical
distribution, 506, 507, 508, 511
Rhynchonellidae, 487, 501, 505 ; strati-
graphical distribution, 507, 508, 511
Rhysota, 67, 3810, 314, 316, 319, 440
Rhytida, 319-826, 333, 359, £40 ; habits,
54; radula, 232
Rillya, 442
Rimella, 418
Rimula, 265, 406
Ringicula, 430; radula, 230
Risella, 413
Rissoa, 415
Rissoina, 415
Robillardia, 77
Rochebrunia, 331, 414
Rock-boring snails, 49
Rolleia, 549
Rossia, 389
Rostellaria, 418
Rudistae, 456
Rumina, 260, 442
Runcina, 431; protective coloration, 73
SABATIA, 430
Sactoceras, 394
Sagda, 348-351, 441
Sageceras, 398
Salasiella, 353, 440
Salivary glands, 237
Sandford, on strength of Helix, 45
Sandwich islanders, use of shells, 99
Sanguinolaria, 456
Sarepta, 447
Sarmaticus, 409
Satsuma, 314, 316, 441
Saxicava, 447, 457
Saxidomus arata, money made from, 97
Scalaria, 247, 263, 411; radula, 224
Scaldia, 452
Scalenostoma, 422
Scaliola, 415
Scaphander, 428, 429, 430;
231; gizzard, 238
Scaphites, 399, 399
Scaphopoda, 444; defined, 6; breath-
ing organs, 160; nervous system,
205; radula, 236
Scaphula, 14, 305, 448
Scarabus, 18, 278, 489, 439
Scharff, R., on food of slugs, 31; on
protective coloration in slugs, 70
Schasicheila, 347, 351, 354, 410
radula,
INDEX 531
Schismope, 266, 407
Schizochiton, 187, 402, 403
Schizodus, 448
Schizoglossa, 325, 440
Schizoplax, 403
Schizostoma, 413
Schloenbacia, 398
Scintilla, 175, 453
Scissurella, 265, 407; radula, 226
Sclerochiton, 403
Scrobicularia, 15, 164, 453; siphons,
164
Sculptaria, 333
Scurria, 405
Scutalus, 356, 442
Scutellastra, 405
Scutus, 245, 406, 406
Scyllaea, 433 ; jaws, 212 ; stomach, 239
Segmentina, 320
Selenites, 339, 341, 440
Selenitidae, radula, 231
Selenochlamys, 296
Self-fertilisation, 42-44
Semele, 453
Semicassis, 420
Semper, K., on habits of Limnaea, 34;
of Helicarion, 45, 67; on mimicry,
67; on parasitic Hulima, 79; on de-
velopment of Limnaea, 84, 94; on
sexual maturity in snails, 129; on
Onchidium, 187
Sepia, 381, 385-887, 389; egg-capsules,
127; glands, 136; jaws, 214; radula,
236 ; alimentary canal, 238 ; ink-sac,
241 ; hectocotylus, 389
Sepiadarium, 389
Sepiella, 389
_ Sepiola, 389; glands, 136 ; radula, 236
Sepioloidea, 389
Sepiophora, 388
Sepioteuthis, 390; hectocotylus, 139
Septaria, 337, 3388, 410
Septibranchiata, 145, 167, 459; bran-
chiae, 166
Septifer, 274, 449
Sequenzia, 420
Sergius Orata, 104
Serrifusus, 424
Sesara, 305, 440
Sex, differences of, 133
Shell, 244 f.; internal, 174; shape of
bivalve, 445
Shell-gland, primitive, 132
Shells as money, 96 f. ; as ornament,
etc., 98 f.; various uses of, 98 f.;
prices given for rare, 121 ; sinistral,
249
Shores of N. Asia, no littoral fauna, 2
Showers of shells, 47
Sigaretus, 186, 245, 267, 477; foot, 198
Sight, 180
Silenia, 459; branchiae, 168
| Silia, 425
Siliqua, 274, 457
Siliquaria, 248, 418
Simnia, 419
Simpulopsis, 345, 350, 442
Simpulum, 420
Simroth, on recent forms of Helix, 22;
on food of slugs, 31; on crawling of
Helix, 45
Singular habitat, 48
Sinistral shells, 249
Sinistralia, 424
Sinusigera, 138
Sipho, 424
Siphonalia, 424
Siphonaria, 18, 431; classification, 19 ;
breathing organs, 151, 152
Siphonarioidea, 437
Siphonodentalium, 444
Siphonostomata, 156
Siphonotreta, 493, 496, 504; strati-
graphical distribution, 507, 508
Siphons, 178; in burrowing genera,
165 ; branchial, 155
Sistrum, 75, 423; radula of S. spec-
trum, 79, 222
Sitala, 301, 304, 310, 314-819, 333, 440
Skirgard, Mollusca of the, 13
Skenea, 415
Skenidium, 505, 508
Slit, in Gasteropoda, 265, 406
Slugs, habits and food of, 30 f. ; bite
hand of captor, 33 ; in bee-hives, 36 ;
in greenhouses, 36; protective col-
oration, 70; eaten in England, 120
Smaragdia, 21
Smaragdinella, 430
Smell, sense of, 192
Smith, W. Anderson, quoted, 98, 111,
114, 191
Snails as barometers, 50; plants fer-
tilised by, 102; cultivation for food,
118 f. ; used for cream, 119 ; as medi-
cine, 120 ; banned by the Church, 121
Solariella, 408; radula, 225
Solarium, 264, 412, 418; radula, 224
Solaropsis, 343, 353-357, 442
Solecurtus, 165, 457
Solen, 171, 446, 457;
habits, 45
Solenaia, 452
Solenomya, 275, 448
Solenotellina, 456
Solomon islanders, use of shells, 98
Somatogyrus, 415
Sophina, 305
Spallanzani, experiments on Helix, 163
Spat, fall of, 113
Spatha, 294, 331, 336, 452
Spekia, 333
Spermatophore, in Cephalopoda, 137 ;
in Helix, 142
vision, 190;
532
Spermatozoa, forms of, 136
Sphaerium, 453
Sphenia, 456
Sphenodiscus, 398
Sphyradium, £442
Spines, use of, 64
Spiraculum, 266, 414
Sptraxis, 442
Spirialis, 249
Spirifera, 468, 501, 505 ; stratigraphical
distribution, 507, 508, 511, 512
Spiriferidae, 501, 505, 508
Spiriferina, stratigraphical
tion, 507, 508
Spirobranchiata, 464
Spirotropis, 426; radula, 218, 219
Spirula, 247, 386, 387, 388
Spirulirostra, 380, 586, 388
Spondylium, 500
Spondylus, 257, 446, 450, 450; ocelli,
191; genital orifice, 242
Spongiobranchaea, 437
Spongiochiton, 403
Sportella, 453
Starfish eat oysters, 110
distribu-
Stearns, R. E.C., on tenacity of life, 38 |
Stegodera, 306
Stenochisma, 505; stratigraphical dis-
tribution, 507, 508
Stenogyra, 324, 442; S. decollata, 279 ;
food, 54 ; smell, 194 ; Goodallii, 279 ;
octona, sudden appearance, 47
Stenogyridae, radula, 254
Stenopus, 440; habits, 45
Stenothyra, 415
Stenotis, £16
Stenotrema, 340, 441
Stephanoceras, 399
Stepsanoda, 358
Stilifer, 76, 77, 79, 422
Stiliferina, 76, 422
Stiliger, 432
Stilina, 76
Stoastoma, 348-851, 410
Stoloteuthis, 389
Stomach, 239
Stomatella, 408
Stonatia, 408
Stomatodon, 302, 417
Strebelia, 353, 440
Strength of Helix, 45
Strephobasis, 417
Strepsidura, 424
Streptaulus, 414
Streptaxis, 302, 306, 309, 314-331, 3438,
357-359, 440 ; variation, 87
Streptoneura, 203, 404
Streptosiphon, 424
Streptostele, 329, 338, 440
Streptostyla, 343-355, 353, 440
Stricklandia, 505 ; stratigraphical dis-
tribution, 507, 508
|
|
MOLLUSCA — BRACHIOPODA
Strigatella, 425
Stringocephalidae, 506, 508
Stringocephalus, 492, 497, 498, 500,
501, 506; stratigraphical distribu-
tion, 507, 508
Strobila, 340, 345-3538
Strobilops, 442
| Strombidae, habits, 64; penis, 186
Strombina, 423
Strombus, 69, 200, 252, 478; mimick-
ing Conus, 69; operculum, 78, 269 ;
pearls from, 101; ; metapodium, 199;
stomach, 239
Str ophalosia, 504; stratigraphical dis-
tribution, 507, 508
_ Stropheodonta, 497, 505, 508
Strophia, 345-355, 442; S. nana, 278
Strophochilus, 358, 441
Strophomena, 499, 505; stratigraphical
distribution, 507, 508
Strophomenidae, 500, 505, 508
| Strophostoma, 248, 41h
| Structure of shell, 252
Struthiolaria, 99, 418 ; radula, 216
Styliola, 437
Stylodonta, 339, 441
Stylommatophora, 11, 181, 439; origin,
19
| Subemarginula, 406
Submytilacea, 451
Subularia, 422
Subulina, 332, 352, 442
| Subulites, 420
Succinea, 325, 327, 358, 433 ; jaw, 211;
S. putris, parasite of, 61
Succineidae, 443; radula, 234
Sudden appearance of Mollusca, 46
Suessia, stratigraphical distribution,
507
Sulphuric acid, 2387
Surcula, 426
Sycotypus, 424
Synaptocochlea, 408
Syndosmya, 453
Syringothyris, 500, 508
Syrnola, 422
Syrnolopis, 332, 383
Systrophia, 356, 357
TACHEA, 441
Taenioglossa, 223, 411
Taheitia, 414
Talona, 457
Tanalia, 304, 417
Tancredia, 453
Tanganyicia, 332, 415
Tanganyika, L., fauna of, 12
Tanysiphon, 454
Taonius, 391, 391
Tapes, 454.
Taste, 179
Tebennophorus, 143, 340, 440
INDEX
Tectarius, 413
Tectibranchiata, 10, 429
Tectura, 805, 405
Tectus, 408
Teeth in aperture of the shell, 63
Teinostoma, 247, 408
Teinotis, 407
Telescopium, 252, 416
Tellina, 446, 458, 453;
variation, 84
Tellinacea, 453
Telotremata, 511
Tenacity of life, 37
Tenison-Woods, on red blood, 171;
on shell-eyes, 189
Tennent, Sir J. E., on musical sounds
produced by Mollusca, 50
Tennentia, 304, 314, 338, 440
Terebellum, 418 ; jumping powers, 64
Terebra, 246, 265, 426, 426; radula,
219
Terebratella, 468, 487; distribution,
486 ; fossil, 506 ; stratigraphical dis-
tribution, 508
Terebratula, 467, 468, 487; size, 484;
distribution, 485, 486; fossil, 492,
499, 506; stratigraphical distribu-
tion, 506, 507, 508
Terebratulidae, 487; fossil, 500, 505,
506 ; stratigraphical distribution, 507,
508
Terebratulina, 466, 479, 487; larva,
482; distribution, 486; fossil, 506;
stratigraphical distribution, 508;
form of shell, 510
Teredina, 457
T. balthica,
Teredo, 262,457, 458 ; nervous system, |
206 ; intestine, 241
Tergipes, 432
Terquemia, 450
Testacella, 22,52, 440 ; habits, etc., 49,
51 f.; pulmonary orifice, 160; eyes,
186; radula, 231; anus, 241
Testicardines, 466, 487; muscles, 476 ;
fossil, 497, 504; external characters,
497 ; internal characters, 499 ; attach-
ment of muscles, 501 ; stratigraphical
distribution, 508
Testis, 135
Tethyidae, 216
Tethys, 432
Tetrabranchiata, 397 f.
Thala, 425
Thalassia, 319
Thalotia, 408
Thapsia, 329
Thaumasia, 349, 442
Thaumastus, 356, 442
Thecacera, 434; radula, 229
Thecidiidae, 487 ; fossil, 501, 506, 508
Thecidium, 475, 479, 480, 483, 487;
fossil, 506, 508
533
Thecosomata, 435
Thelidomus, 346-351, 350, 441
Theora, 453
Therasia, 441
Thersites (Helicidae), 522, 525
Thersites (Fasciolariidae), 424
Thetis, 454
Thracia, 245, 459
Thread-spinning, 29
Thridachia, 432
Thyca, 76, 79
Thyrophorella, 330, 440
Thysanoteuthis, 390
Tiedemannia, veliger, 182
Tiphobia, 332, 333, 417
Titicaca, L., Mollusca of, 25
Todarodes, 390
Tomichia, 414
Tomigerus, 334, 356, 358, 442
Tomocyclus, 354
Tomostele, 330, 440
Tonicella, 403
Tonicia, 403 ; eyes, 188
Torellia, 411
Torinia, 413 ; radula, 224; operculum,
269
Tornatellina, 278, 319, 828-327, 388,
358, 443
Tornatina, 250, 430
Torquilla, 442
Toucasia, 455
Touch, sense of, 177
Toxoglossa, 218, 426
Trachia, 314
Trachyceras, 397
Trachydermon, 403
Trachyteuthis, 389
Tralia, 439
Transovula, 419
Trematis, 492, 493, 504; stratigraphi-
cal distribution, 507, 508
Trematonotus, 407
Tremoctopus, 384; radula, 286; hec-
tocotylus, 187
Trevelyana, 434
Trichia, 316
Trichotropis, 275, 411
Tricula, 302
Tridacna,. 278, 455
Triforis, 416 ; radula, 224
Trigonellites, 397
Trigonia, 15, 254, 269, 448; jumping
powers, 65; distribution, 370
Trigonochlamys, 296, 440
Trigonostoma, 426
Trimerella, 495, 504, 508, 511
Trimerellidae, 493, 494, 496, 504; strat-
igraphical distribution, 507, 508
Trinacria, 448
Triodopsis, 340, 441
Triopa, 434
Triopella, 484
534
MOLLUSCA — BRACHIOPODA
Triopha, 434
Tritaxeopus, 385
Triton, 256, 275, 420; jaws, 212
Tritonia, 433; protective coloration, 71
Tritonidea, 424
Trivia, 419
Trochidae, egg-capsules, 125
Trochiscus, 408
Trochita, 248, 412
Trochoceras, 395
Trocholites, 395
Trochomorpha, 806, 521, 324, 327, 333,
441 ;
Trochonanina, 331, 440
Trochosphere, 5, 130
Trochotoma, 266, 407
Trochus, 265, 408 ; eye, 182; stomach,
239
Trophon, 423
Tropical beach, Mollusca of a, 3
Tropidophora, 414
Tropites, 397
Troschelia, 424
Truncaria, 423
Truncatella, 260, 414
Tryblidium, 405
Trypanostoma, 340
Trypho of Lampsacus, prayer against
snails, 121
Tubed operculates, 157, 266, 300, 307,
309
Tudicla, 424
Tudora, 291, 349, 351, 414
Tugonia, 456
Tulotoma, 340, 416
Turbinella, 100, 262, 264, 424, 424
Turbo, 409; eye, 182; osphradium,
195 ; operculum, 268
Turbonilla, 250, 332, 422
Turcica, 408
Turricula, 425; radula, 221
Turrilites, 399, 399
Turritella, 252, 417; radula, 215, 224
Tyleria, 459
Tylodina, 431
Tylopoma, 416
Tympanotonus, 416
Tyndaria, 447
Typhis, 423
ULTRA-DEXTRAL Shells, 250
Umbonella, 409
Umbonium, 409
Umbrella, 10, 431; radula, 217, 230
Uncites, 505; stratigraphical distribu-
tion, 507, 508
Underground snails, 48
Ungulina, 452
Unicardium, 452
Unio, 452; shell, 254, 259, 278, 341;
variation, 92
Union of Limazx, 128
Unionidae, origin of, 15; eaten by rats,
57; larvae, 146
Urocyclus, 381, 440
Urosalpinz, 423
Utriculus, 430
Uvanilla, 409
VAGINULA, 245, 319, 348, 352, 443
Vaginulidae, radula, 234; anus, 241
Valletia, 456
Vallonia, 441
Valwvata, 1383, 416; branchia, 159
Valves of Chitonidae, 401 f.
Vanganella, 454
Variation, 82 f.
Varicella, 346, 348
Velates, 260, 410
Velifera, 353, 440
Veliger stage, 131; mistaken for per-
fect form, 133
Velorita, 302, 453
Velum, 151
Velutina, 275, 411; radula, 223
Veneracea, 454
Venericardia, 451
Venerupis, 454
Veniella, 451
Venilicardia, 451
Venus, 270, 271, 446, 454; V. merce-
naria, 97, 3874
Verania, 391
Vermetus, 247, 418; radula, 228
Veronicella, 443
Verticordia, 458
Vertigo, 827, 442; V. arctica, 287
Vexilla, 423
Vibex, 417
Vitrella, 289
Vitrina, 22, 296 f., 382, 440; hardy
habits, 24; jumping powers, 65;
shell, 175; radula, 217
Vitrinella, 408
Vitriniconus, 314, 440
Vitrinoidea, 314, 440
Vitrinozonites, 340, 440
Vitularia, 423
Vivipara, 324, 343, 416
Volume of water, effect in producing
variation, 94
Voluta, 267, 425, 425; spawn, 125;
radula, 217, 221; distribution, 370;
prices given for rare, 122
Volutaxis, 348
Volutharpa, 267, 424
olutolithes, 425
Volutolyria, 425; radula, 222
Volutomitra, 425; radula, 221
Volutopsis, 423
Volvaria, 429
Volvatella, 430
Volwula, 430
Vulsella, 75, 446, 449
INDEX
WALDHEIMIA, 464, 467, 468, 473, 474,
487; size, 484; distribution, 486;
fossil, 500, 501, 502, 506, 508
Walton and mussel cultivation, 115
Wampum, 97
Warner, R., quoted, 37
Warning coloration, 71 f.
West Coast, South America, melanism
of shells occurring on, 85
Whelks, use of, 118
Whitneya, 424
Whitstable, oyster-parks at, 106, 112
Willem, V., on vision of Mollusca, 185
Wollaston, T. V., quoted, 32
Wood, Rev. J. G., on starfish eating
oysters, 111
Woodia, 451
Woodward, S. P., on tenacity of life,
38; Dr., on the same, 38
Wotton, F. W., on egg-laying of Arion,
42
Wright, Bryce, on tenacity of life, 38
Dale,
XENOPHORA, 412; habits, 64
Xenopoma, 346, 351
Xerophila, 285, 296, 441
Xesta, 310, 319, 821, 440; mimicry by,
66 f.
Aylophaga, 457
YETUS, 425
Yoldia, 447; genital orifice, 242
ZAGRABICA, 297
Zebrina, 285, 296, 442
Zeidora, 406
| Zidona, 425
Zittelia, 420
Zones of depth, 361
Zonites, 275, 440; food, 33; radula,
232 ; distribution, 294, 296, 340
Zospeum, 187, 442
Zygobranchiata, 154, 406
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