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Fig. 1.—A Group of Land-Snails. Frontispiece.

Helix arbustorume. L[Telix fructicum.
felix hortensis.

Helix nemeralis.

Boung Collector Series. ]
‘LAND AND FRESH-WATER SHELLS:

aN ANTRODUCTION 7O THE STUDY OF
CONCHOLOGY.

Ay ae ~

EB LIAMS. MA... Disc. oho As
he

GoLtp MEDALLIST, S.Sc., Lonpon;

Member of the Conchological Society of Great Britain and Ireland ; Member of the
Scottish Meteorological Society; Conchological Referee to the Wesley
Scientific Society; Author of “ The Shell-Collector’s
Handbook for the field.”

WITH A CHAPTER ON THE

mS tRmepOULION- OF THE BRITISH LAND AND

FRESH-WATER MOLLUSCA,
>.
x Sl rT.
Pow: TAYLOR. Fis.
as
Editor of ‘The Fournal of Conchology” ; Ex-President of the Conchological Society oy

Great Britain and lreland; and Membre Honoraire de la Société
Malacologique de France ;

se AND

“DENISON BOBEUCK: E.L.S.
Diy vision of t Mc Husk,

~ 2
oF

LONDON :

- SWAN SONNENSCHEIN & CO,,
PATERNOSTER SQUARE.

I 880.

IO.

i

“I Ov BB wo

Uniform with this Volume. Price Is. each

(post free, 1s. 2d.).

; BUTTERFLIES, MOTHS, AND BEETEES:

By W. F Krrey.

- CRUSTACEANS. AND SPIDERS: By

PS AL AL SKUSE:

- SUNG, LICRENS, ETC... By PerersGrag.

. MOSSES. By James E. BAGNALL.

- POND-LIFE: By E. A. BUTLER:

, SEAWEEDS, SHELLS, AND FGSSIES: {By

PETER GRAy and B. B. Woopwarp.

- ANTS, BEES, WASPS, AND. DRAGON

FLIES. By W. Harcourt-BaTu.

8. SILK WORMS. By E. A. BuTLER.
9. BRITISH BIRDS. By R. BOWDLER SHARP.

[Shortly.
REPTILES AND BATRACHIANS.. By

CATHERINE C. HOPLEy.

LAND AND FRESH-WATER SHELES:
By Dr. W. Wituiams, J. W. Taytor and W. D. Rorsuck.

. £ 1S ES, By oA. A SRUSE. [ Shortly.
“MAMMALIA. By F. A.-A.:SKUSE. [Shortly

Extra Series.

. COINS AND TOKENS (English). By L.

Jewitt.

LONDON : SWAN SONNENSCHEIN & Co.

OP s¥38~

JAN 7 4.1943

i

anscribed
TO THE MEMORY OF THE

GREATEST CONCHOLOGIST OF HIS TIME,

J. -P.. R. .DRAPARNAUD

(BORN 1772, DIED 1804).

CN WN ae

CHAPTER a.

PAGE
COLLECTING AND PRESERVING SNAILS, MUSSELS, AND SLUGS 9
CHAPTER. II.

THE ANATOMY AND PHYSIOLOGY OF A SNAIL . . saat

CHAPTER? Mil.

THE ANATOMY AND PHYSIOLOGY OF A FRESH-WATER MUSSEL 45

CHAPTER. TV.

THE CLASSES, ORDERS, FAMILIES, GENERA, SPECIES, AND

VARIETIES OF BRITISH LAND AND FRESH-WATER SHELLS 59

CHAPTER V.

THE DISTRIBUTION OF THE BRITISH LAND AND FRESH-WATER

MOLLUSCA (J. W. TAYLOR AND W. DENISON ROEBUCK) . 94

Pie Ace BE.

Tue burden of this little volume of “The Young Collector
Series ” is to supply a want often felt and often expressed by
our younger naturalists, who cannot afford to give the high
prices asked for books upon the subject of which it treats.
At the same time it must not be looked upon as a finished
monograph, nor yet as the only manual that will be needed
by the student. As he makes advances in the after-days
he will require the larger text-books of Moquin-Tandon,
Gwyn Jeffreys, Forbes and Hanley, Rossmassler, and my
other work, “ The Shell-Collector’s Handbook for the Field,”
to which this little volume may serve as an introduction. In
the following text, the anatomy of the snail and fresh-water
mussel has been given at some length, since the basis of our
work must be founded on structural details, and to make
these chapters as full as possible, all the available sources
of Continental and Home literature have been searched for
information. The whole of the species of our land and
fresh-water mollusca are described, and their most common
varieties are given in footnotes. To my friends, Mr. J. W.
fayioe YL.S., and Mr. W. Denison -Roebuck, F.L.S., I
must express my indebtedness for allowing me to reprint
here the chapter on distribution from The Journal of Con-
chology, which they have kindly brought up to date for
the purposes of this volume; and I must also express the
obligations I owe to that great army of workers (too

8 PREFACE.

numerous to mention individually) who, of late years, have
done so much towards a fuller understanding of the subject,
and from whose published works and papers I have largely
culled much interesting and valuable information. My last
word, in conclusion: should the young collector be ever at
a loss to name a snail or a slug, let him send the specimen
to me, enclosing the return postage, when I will do all in my
power to help him over his difficulty.
“Go, child of nature, to thy mother’s breast,
And learn the lesson she can teach so well ;

No longer in the lap of folly rest,
But hear the truths that nature loves to tell.’

J. W. W.

MIDDLESEX HOSPITAL, LONDON, W.,
AND MITTON, STOURPORT, WORCESTERSHIRE,

LAND AND FRESH-WATER SHELLS.

CIALP EER I.
COLLECTING AND PRESERVING SNAILS, MUSSELS, AND SLUGS.

In my ‘Shell-Collector’s Handbook for the Field,” I have laid
down five rules to be strictly followed when out collecting, which,
advisably, may be recapitulated here. They are as follows :—

1. Never leave a stone unturned.

2. Never pass by a nettle without a full examination of its stem,
branches, leaves, and the vegetation which grows below and
around it.

3. Never leave untouched, and unexamined, moss at the roots
of trees, or the dead leaves under them.

4. Always examine the vegetation on walls, and the grass which
grows around their foundations.

5. Never forget, when searching for water-specimens, to examine
the water-plants, and the under surface of. any floating log of
wood, as well as the bed of the pond, brook, or stream. An
examination of caddis-cases will also often give a large number of
water specimens.

In a review of the book from whence the above rules have
been extracted, which appeared in one of our Natural History
“ Monthlies,” the reviewer in touching upon these points
expressed himself to the effect that when an individual is observed
to be faithfully carrying them out “‘ we may rest assured that we
are watching the shell-collector on the war-path.” No; ‘the
shell-collector”’ is only ‘‘on the war-path”’ when he searches
everywhere, for snails and slugs are omnipresent creatures, and are
not, on the whole, very particular as to where they make their

9?

ime) LAND AND FRESH-WATER SHELLS.

abode. The rules are what I term “golden rules;”%z.¢., Toles
not to be forgotten ; but the one rule of the assiduous collector is
to search in every crink and cranny, and never to pass Over a
spot without a full examination of its z/ole surface. The imple-
ments needed for this collecting are few in number and inexpen-
sive. ‘Two of them are given you by nature—nimble fingers and
quick eyes ; one forms a companion in your walks,—the walking-
stick ; the others, which will have to be purchased, are’a dredge,
a scoop, or a water-net, and a few chip boxes. The walking-stick
will be useful for pulling water-weeds to the bankside, so that
they may be easily examined with the fingers for specimens. The
dredge will be needed for the collection of Unzos, Anodons,
Spheria, and Pisidia, which, being bivalves, live almost entirely
on the bed of the pond or stream. This can be made after the
following figure of a net-dredge recommended in Messrs. Gray

Fig. 2.—A Water-dredge (Woodward).

and Woodward’s companion volume, “Seaweeds, Shells, and
Fossils ;” but my preference is to having a properly weighted
square frame rather than a circular one, as it takes a larger area
of the water-bed at the same time, and, consequently, is more apt
to work up a larger number of specimens. The scoop is not in
general use, I think, but, nevertheless, it is an exceedingly good
implement to use for sweeping among water-weeds which cannot
be brought to the bankside with the stick, and perhaps is more
welcome and more serviceable than the ordinary water-net, for
which it forms a substitute. Mr. Wallis Kew and I have taken
a large number of specimens with it from the Tottenham Marshes,
—by the way, a happy hunting ground for the London collector.
Mr. Denison Roebuck has his made of copper, but zinc will be
found cheaper and nearly as serviceable a material. A circular
ring of zinc is made, of about an inch and a quarter in depth,
and of about eight inches in diameter. A perforated zinc bottom

COLLECTING AND PRESERVING SNAILS, ETC. II

is then soldered on, and also a zinc handle for a stick to fit into is
made and soldered on, or better, riveted to the zinc ring, so that,
when finished, it resembles in shape, more or less, a small brewing
sieve. Thus it is stronger than the net, and can be wielded with
a more powerful hand without much fear of mishaps occurring to
spoil the day’s collecting. Should, however, the net be preferred,
it should be made of strong book-muslin, of an oblong bag-shape,
and the ring should be of thick galvanised iron. The chip boxes
can be bought in nests from any dealer at a cheap rate, and their
utility consists simply in forming pocketable boxes in which to
carry home your specimens. The paraphernalia, then, is only
wanted for water-specimens ; for land-shells and slugs nothing is
needed but your own fingers and eyes.

The specimens, we must now assume, are collected, and taken
home to be made ready for a place in the collection. How are
they to be made ready? In the first place, they must be killed ;
in the case of the snails, by boiling water, and, in the case of the
slugs, by drowning. The animals of the shells must then be
extracted. With the univalves this is done best with a bent pin;
with the bivalves the animal is best extracted by the small blade of
the pocket-knife, or by a small scalpel. The shells of the univalves
are then well cleaned by hard brushing with a tooth-brush dipped
in pure water; the shells of the bivalves are to have their two
valves tied together tightly with cotton or string so that the
ligaments may dry, and so prevent them from divaricating, after
which they are to be cleaned in the fashion employed with the
univalves. Mr. Roebuck is not inclined to clean his shells, as
he thinks the amount of confervoid growth often interesting ;
but this must be left to the personal ideas of the collector alone.

It is quite another method with the slugs. Their shells may
be extracted from underneath the mantle (except in TZestace//a,
where the shell is situated on the tip of the tail) by the pen-
knife, and glued on cardboard or kept loose in chip boxes, or
the animal itself may be preserved in one of two ways. It
may be preserved by the dry or by the wet method. ‘There
are two dry methods. In one—recommended by Hiitbner—the
animal is killed by immersion in methylated spirit, and the whole
of the viscera is extracted through a longitudinal incision made

¥2 LAND AND FRESH-WATER SHELLS.

along the under surface of the foot in the middle line; the place
which the viscera held is stuffed with wadding, and the skin is
dried and varnished. In the other—recommended by Dubreuil
—the slug is killed and washed in pure water, to which, after the
lapse of eight hours, some salt is added. A slit is then made
along the left side, and the animal skinned. Thus, by means of
two more longitudinal slits, three preparations can be made—one
to show the back, one the foot, and the third the right side with
the pulmonary orifice. These are glued on cardboard, varnished
with white shellac varnish, to which a little corrosive sublimate
has been added, and duly labelled.*

The wet method is simply their immersion in some one fluid
preservative medium. This may be turpentine, equal parts of
glycerine and methylated spirit, or preferably one of the following
fluids, which can be made with slight trouble.

(1). Wickerheimer’s Fluid.

Dissolve in 3,000 grammes of boiling water—

100 - alum,
25 as common salt,
12 5 saltpetre,
60 1 carbonate of potash,
10 arsenious acid.

This solution is to be cooled and filtered, and to every ten litres
of it four litres of glycerine and one litre of methylated spirit are
to be added.

(2). Poetz and Hohr's Flutd.

Arsenious acid ... on oe ... 12 grammes
Sodium chloride ho Nef BP UGS ie
Potassium sulphite .... Me Paes, ip

= nitrate gs Ge TG

& Carbonate. .: 52 ela ”
Water. ~~... Ene sich — ... 1o litres
Glycerine a a, a Sen: ad =.
Wood-naphtha ... oe eat ume: he

* There is a separate method for the preservation of Zestacella. The animal
is dried in sand, then slit along its under surface, stuffed with cotton wool,
and redried.

COLLECTING AND PRESERVING SNAILS, ETC. 13

(3)

Water a bee S03 Fe .»- 800 parts
Chloride of zinc... oe v3 nr EOS? 52
Dissolve.
(4).
White sugar ae = We .t« 206 parts
Methyl-spirit 5 ae ae Sutelt AOC:
Common salt we =, Ais era (-10 se
Nitrate of potash ... oie sos je SRO
Water ae ae Get ate Se. te PROS races
(5).
Hyposulphite of soda __... ... q.s. to make a saturated

solution in

Water )
Methylated spirit J equal parts.

The slugs, well cleared of their mucus, are to be placed in any
one of the above media, in small cylindrical glass tubes and
tightly sealed, so as not to admit air. This sealing can be done
by means of tightly fitting corks, subsequently covered over with
a coating of Brunswick black, or by the use of glass tops cemented
down with a mixture of o/d guttapercha, five parts, and asphalt,
four parts, melted together and applied hot.

In concluding this chapter, I would strongly advise you not to
go to the expense of buying cabinets wherein to lodge your shells.
Rather purchase large books on the subject with your money.
Cardboard trays are all that is needed for storage purposes. In
them lay the shells on cotton-wool, with a label bearing the date
of capture and the locality, also the specific and—if a variety—
the varietal name, but these are not so important as the locality,
for the shells carry their own identification with them.

CHAR VER SE:
THE ANATOMY AND PHYSIOLOGY OF A SNAIL.

TAKE a live Wrinkled Snail (felix aspersa) or Roman Snail
(Heltx pomatia), and allow it to crawl along a piece of paper
before you. Note—

1. That part only of the animal is extruded (frostoma), the
other portion (mefastoma, or visceral hump) being permanently
lodged within the shell.

2. On the prostoma note—

(a) The head segment, forming its anterior extremity, and bearing
two pairs of processes or tentacles ; the upper pair, carrying the
eyes (dorsal tentacles, or ommatophores), are much longer than the
lower pair (ventral tentacles).

(6) The south on the anterior extremity of the head segment,
bounded by a cevcular and a lateral lip.

Fig. 3.—Helix pomatia. O, ommatophore; Pe, foot.

(¢) The foot, forming a well-marked muscular expansion on the
under surface of the prostoma.

(2) The orifice of the pedal gland, between the mouth and the
foot.

(e) The genital orifice, slightly below and slightly behind the
right dorsal tentacle.

ANATOMY AND PHYSIOLOGY OF A SNAIL. 15

(f) The collar of the mantle, a portion of the mantle-edge just
visible beneath the aperture of the shell. Notice in this, on the
right side, the pu/monary aperture, the anus, and the external orifice
of the duct of the renal gland.

(¢) The pulmonary orifice, a large foramen situated on the right
side of the mantle-collar, and leading into the mantle cavity.

(i) The azus, opening side by side with, and slightly to the right
of, the pulmonary orifice.

(2) ‘Che orifice of the duct of the renal gland, opening just inside
the pulmonary orifice. |

Kill the snail by drowning, and place in spirit for a few hours.
Twist the animal out of the shell, and replace it in the spirit. On
the shell note—

(2) The colour and markings.

(4) Its conical shape. ‘This may be discoid, as in Planorbis
complanatis ; oval, as in Amalia marginata ; or ear-shaped, as in
Testacella haliotidea.

(c) Its division into four ze/or/s, the largest being known as the
body-whorl.

(d) The aperture, peristome, or peritreme, through which the snail
extends its prostoma. ‘This is toothed in some species, as Pupa
secale, Vertigo pusilla, and Vertigo antivertigo.

(ec) The xucleus, or apex of the cone, the oldest part of the shell
corresponding to the umbo of the Lamellibranch shell.

(f) The Zines of growth, running parallel to the aperture.

(¢) The varices, numerous well-marked lines extending across
the body-whorl, and differentiating one year’s growth from
another.

(2) The columella, or axis around which the whorls turn.

(¢) The wmbzlicus, a foramen on the under surface of the shell,
opening into the cavity of the columella.

(7) Ina hibernating specimen, notice the ef7phragm, which com-
pletely closes the mouth of the shell. Examine with a lens its
under surface, and notice a small opening in its central portion
for the admission of air for respiratory purposes.

THE SHELL GENERALLY CONSIDERED.—The shell of the adult
Gastropod, with the exception of the internal shell of Avion and
Limax and the nucleus of C/ausilia, is a secondary growth formed

16 LAND AND FRESH-WATER SHELLS.

by the mantle, not by the shell-gland of the embryo. In structure,
according to the researches of Longe and Mer, it may be said to
consist of three layers,—a cuticle (epidermis, periostracum), a honey-
comb layer, and a nacreous or mother-of-pearl layer. The first of
these layers is formed by a cutogenic apparatus composed of an
“epithelial organ” of bottle-shaped cells secreting granules, and
of numerous glandular czeca which open into a line—the ‘“ pallial
/ine”—situated just behind the collar of the mantle. Nalepa has
found that in Zonztes algirus the cells of this ‘‘ epithelial organ”
develop in spring, the period of greatest growth, but after that—z.e.,
during summer, autumn and winter—they gradually atrophy, and,
according to Longe and Mer, they are entirely wanting in the
full-grown animal. ‘The colour of the shell is secreted by the uni-
cellular glands of the mantle, the second layer by the edge of the
mantle, and the third layer by the whole surface of the mantle.
The honeycomb layer is composed of a superficial and a deeper
portion ; the former shows a confused striated appearance, the
latter consists of vertical prisms. The nacreous layer is arranged
in three super-posed series of calcareous lamellze, those of the outer
and inner layers running parallel to the suture, and the middle
layer at right angles to it. Splinters of the shell are hard enough
to scratch Calc-spar; the form in which the calcareous matter
exists Is represented by Arragonite (Ca Cos) in the mineral king-
dom. In chemical composition the shell is made up of about
95-98 per cent. of carbonate of lime, of about 1°5 per cent. of an
organic substance termed conchiolin, and of magnesium carbonate,
silica, and alumina, with phosphates, in small quantities.

The mouth of the shell is closed in some species by an efzphragm,
in others by an operculum, and in others still by a clausilium.
Each of these structures requires a few words. ‘The epiphragm is
a film of mucus impregnated by calcareous salts secreted over the
aperture of the shell in some species, as the /Ye/ices, previous to
hibernation. Barfurth has shown that the calcareous salts are a
secretion of the cells of the digestive gland. The adhesion that
takes place between the epiphragm and the peristome of the shell
is dissolved away by an excretion of fluid mucus from the mantle,
at what time the trees under the influence of returning warmth
first burgeon into shoots of freshest green, after which it is easily

ANATOMY AND PHYSIOLOGY OF A SNAIL. 17

thrown off by the pressure of the foot. Hammersten finds that
the foot of some snails, as A. fomatia, excretes mucus as well as
the mantle, and possibly this excretion also helps in the disin-
tegration of the epiphragm. ‘The name of epiphragm was first
given to this structure by J. P. R. Draparnaud, to whose memory
this present little volume of conchology is inscribed ; old Martin
Lister (born 1638 (?), died 1712), naturalist and court physician,
who thought he had done everything in natural history that could
be done, called it the operculum saliva confectum ; Miller termed
it the operculum hybernum. ‘The operculum, proper is a horny or
shelly plate attached to the back of the foot in many water-snails,
as Paludina, Neritina, Bythinia, and Valvata, and in a few land
snails, as Cyclostoma and Acme. It contains more conchiolin in
its composition than the shell whose mouth it closes, and not
less conchiolin and more chitine, as Dr. Henry Woodward has
recently supposed. ‘Those Gastropods which have no operculum
are spoken of collectively as the zzopercular univalves ; those with
an operculum, on the other hand, as the oferculated univalves.
No operculum of any shell, whether of fresh-water, land, or
marine habitat, exhibits an annular form. In a marine form,
Lithedaphus ( Calyptrea) equestris, an operculum is attached to the
whole length of the foot, so that on first appearance the shell
might be taken to be a bivalve. But as Professor Owen has
remarked that upon a comparative study of the operculum it gives
characters of secondary importance since it “sometimes varies
in structure in species of the same genus, as it is present in some
Volutes, Cones, Mitres, and Olives (marine forms), and absent in
other species of those genera, and as some genera in a natural
family, as Harpe and Dolium among the Buccinoids, are without
an operculum, whilst the other genera of the same family possess
that appendage.” ‘The operculum grows by the addition of matter
to its circumference, its youngest part being called the zwcleus,
which may be excentric, as in Paludina vivifara, or central, as
in Bythinia Leachit. ‘The clausilium is characteristic of the genus
Clausilia, and differs from the operculum in not being attached
to the animal. It may be best seen by taking a Clauszlia laminata
and breaking away the outer part of the body-whorl, when it will
be found to consist of a shelly plate attached to the columella by
2

18 LAND AND FRESH-WATER SHELLS,

an elastic ligament about half a whorl from the aperture. It
serves exactly the same function in the economy of the animal
as an operculum does among the Paludinidz and Cyclostomatidez.
When the animal extends itself out of the shell the clausilium is
pushed back against the columella, and when it withdraws, the
clausilium flies backwards on account of the elasticity of its
ligament, and closes the mouth of the shell.

The aperture of the shell, generally spoken of as the mouth
feristome, or peritreme, varies greatly in shape in different species.
When it is entire the shell is called holostomatous ; when produced
into a canal for a siphon it is spoken of as szphonostomatous. It
is sometimes reflected over the umbilicus; this is due to the
presence of a lobe in the collar of the mantle of the animal, termed
the columellar lobule. It was John Hunter, the great anatomist,
(born 1728, died 1793), who first noticed that the animal has the
power of absorbing part of its shell, and this will explain the
thinning of some parts of a whorl in a shell in relation to the other
portions, as is sometimes observed. In some species, as Budimus
decollatus, the apex becomes, as the animal grows to the adult
condition, decollated ; z.¢., the physical decomposition of the apex
of a shell, due to the animal leaving it for the lower and larger
whorls as it grows in size. When a shell is injured at the
peristome all the layers are reproduced; when at any other
portion only the middle and internal layers are repaired, and then
the shell is generally thickened internally.

The spire of the majority of the molluscan shells turns to the
right, and the mouth, when placed in its proper position, looks
towards the left; it is then spoken of as dextral or dexiotrope.
In some genera, as Physa, Balta, and Clausilia, the reverse of
this obtains, and then the shell is said to be s¢zzstral or ladtrope—
the spire turns towards the left, and the mouth, placed in its
proper position, looks towards the right.

The colour of the shell varies in different species, and often
in the same species. Camerano has studied the comparative |
rarity and frequency of the colours of the shells of the Mollusca,
and his inferences are that black is rare; brown, grey, yellow,
white, and red common; violet relatively abundant; blue not
rare; and green infrequent. Some shells are unicolorous and not

ANATOMY AND PHYSIOLOGY OF A SNAIL. 19

_ banded; others are unicolorous or banded. Mr. J. W. Taylor,
in his recent “ Valedictory Address as President to the Concho-
logical Society for the year 1887,” published in Zhe Journal of
Conchology for April, 1888, makes the following statement :
‘“‘ Nearly seven years ago Mr. Ashford suggested to me the proba-
bility that elix cantiana, cartusiana, etc., were once banded
species, and I am disposed to agree with his suggestion.” But
there seems to the writer scarcely any foundation for such a sup-
position, and he would disagree with such a statement for five
reasons. In the first place, the primary shell in the embryo of all
species is unicolorous ; in the second place, the youngest portion
(nucleus) of the secondary shell in all species is unicolorous ; in
the third place, unicolorous specimens are most common in aquatic
forms, where environmental circumstances have doubtless not
been so great as on land ; in the fourth place, of a banded species
unicolorous specimens are invariably found ; and in the fifth place,
such a supposition is not general and comparative enough. Thus,
the writer is inclined to the opinion that all the species of our land
and fresh-water mollusca were once, and only, unicolorous. What
the causa causans of the future banding was, we are, practically at
any rate, in doubt. It remains as one of Nature’s greatest arcana
for the great future to solve. .

In HZ. nemoralis and fH. hortensis the bands vary in number and
degree of development, so that it is necessary to have some
system by which we can represent these variations on paper for
the use of our fellow-workers. The system is known by the
name of the system of the band-formule. The type of each
species has five bands, which are represented by the figures
12345, the 123 referring to three bands above the periphery, and
the 45 to two bands below it. When a band is interrupted it is
shown by a colon, thus, 12:45 ; when slightly developed, by the
insertion of the figure representing that band below the line of
the others as 12,45, when obsolete by a cypher, as 02345, or
00000 ; and when two or more bands are fused together into one
band it is shown by bracketing the figures standing for the com-
ponent bands, thus, 123 (45), (123) (45). If more than five bands
be present the extra band is represented by the insertion of the
letter x into the formula, as 12 X 345 or I X 2345.

20 LAND AND FRESH-WATER SHELLS.

Sometimes a shell becomes shaped like a spiral ladder, or
scalarid, as in the accompanying figure of the m. scalariforme of
our common Wrinkled Snail. The shell in Avion may be absent,

Fig. 4.—Helix asfersa. m. scalariforme.

or may consist of a few calcareous granules: in Zémax, the shell
is shield-like ; in both it is situated underneath the mantle. The
grades may be traced from these simple shells to the more
developed shells of the Helices, through the little ear-shaped
shell on the tail of Zestacella haliotidea, and the pretty glassy-
green shell of Vitrina pellucida.

THE BoDY-WALL CONSIDERED GENERALLY.—In the Zimacide
the mantle is visible throughout its whole extent ; in Zaax the
respiratory orifice is on its posterior half; in Avion and Geoma-
facus on its anterior half. It may partly overlap the shell, as in

Fig. 5.—A slug (Zzax) showing the respiratory orifice.

Limnea glutinosa, and in Physa fontinalis, or its fore-edge may
undergo concrescence with the dorsum of the body-wall, as in the
Helicide. In the Limnea the fore-edge is free, and no such con-
crescence has taken place. In Valvata the long plume-like gills
protrude from the mantle cavity when the animal is walking.
There may be four cylindrical tentacles, as in the Limacide and
ffelicide, or only two, as in Limnea and in Physa. When two

ANATOMY AND PHYSIOLOGY OF A SNAIL, 21

tentacles only are present they may be short and triangular, as in
Limnea, very long and cylindrical, as in Planorbis and Physa.
The eyes may be situated on the apices of the dorsal tentacles, as
in Helix, or situated at their base, as in Limncaa, Ancylus, and
Physa, or sessile, as in Planorbis, or placed upon tubercles, as in
Hydrobia, or placed upon pedicels, as in Paludina.

The reproductive orifice is generally a single opening just
behind and slightly below the right tentacle, but in some genera,
as Limnea, Planorbis, and Ancylus, the generative openings are
separated from one another, the male orifice (penzal orifice) being
situated a little anterior to the female orifice (os vagine), a con-
dition of things which seems to be associated with the situation of
the eyes at the base of the tentacles. To those genera in which
these two last-mentioned features obtain Professor Ray Lankester
has given the name of BASOMMATOPHORA, as distinguished from
the STYLOMMATOPHORA, In which there is only one generative
aperture, and the eyes are elevated on tentacles which can be
invaginated into the body-cavity, as the genera Helix, Pupa,
Clausilia, Testacella, Limax, Amalia, Arion, and Onchidium.

The visceral mass may be large and coiled spirally in the shell,
as in the Helcde, Limneide, Cyclostomatide, Paludinide, and
Carychitde, or it may be co-extensive with the foot, as in the
Limacide. ‘The sole of the foot is ciliated in the majority of
terrestrial forms, and this ciliation extends all over the surface of
the body in the aquatic species. In Avion the lateral margins of
the foot are also ciliated, and this feature also obtains around the
margin of the supra-pedal gland and the pulmonary orifice in
Flelix nemoralis and in Amalia marginata. In microscopical
structure the body-wall consists of an epzdermis of columnar cells,
and internally to this a thickened layer of muscle-fibres and
connective tissue. The muscle-fibres are not so differentiated as
those in the.muscle-tissue of vertebrates, but consist of cells which
generally are non-striated, although sometimes they are found to
present an appearance of fine striation. The connective tissue is
described as made up of “ plasma-cells, a matrix, and fibrils.”
The plasma-cells may be irregular in shape, containing refractile
granules, or oval, nucleated, with a clear protoplasm, or they may
contain granules of carbonate of lime. In the oval-shaped cells

22 LAND AND FRESH-WATER SHELLS.

Blundstone has found a substance named glycogen in Hix, and
also in the fresh-water mussel (Azodon), an observation to which
we shall have to refer when treating about the physiology of the
snail. The matrix contains stellate-shaped cells, and in Amalia
carinata and Limax flavus Leydig has observed coloured cells,
termed chromoblasts, which change their contour under the influ-
ence of suitable re-agents. Mucous glands, unicellular in cha-
racter, are scattered all over the body of all Pulmonates, together
with goblet-shaped cells and sensory cells. The mucous glands
are in great quantity on the collar of the mantle; they secrete
mucus, and it is this mucus which forms the threads by which the
slugs and the Zimnea, among land and fresh-water molluscs, and
the Zztiopa and Rissoa parva, among marine forms, suspend
themselves.

Running along the foot in all Pulmonates is a czecal diverti-
culum of the integument termed the supra-pedal gland. In
Cyclostoma elegans there are two. In Avion and Geomalacus a
large slime gland is present at the posterior extremity of the tail ;
in Amalia and Limax this structural feature is absent. The
epithelium of the supra-pedal gland is ciliated, and has been said
to contain sense cells.

Pin the animal down under water, and reflect the mantle and
the integument of the prostoma. Dissect the following systems
out in order :-—

THE DIGESTIVE SySTEM.—The digestive system commences at
the mouth, already noticed, enlarges to form a buccal mass, then
passes back by an cesophagus to form a crop and stomach, and
from thence proceeds through the substance of the digestive
gland, or “ Mitteldarmdriise,” as Frenzel terms it, as the intestine
to end at the anus. The duccal mass or pharynx is a stout
muscular cavity, situated in the head segment, from the lower and

of the radula. This buccal mass contains the masticatory organs.
These consist of a horny beak lying in the circular lip, and of an
odontophore lying below a yellow ribbon containing teeth, known
as the vadula.

The beak plays the function of a mandible in grasping the vege-
table or animal substance on which the animal feeds, while the

:
y
:

5
:
rh

posterior surface of which a pale diverticulum depends,—the sac

;

|

\

ANATOMY AND PHYSIOLOGY OF A SNAIL. 23

radula with its numerous teeth rasps it off into the buccal cavity.
In some species, as Zestacel/a, there is no beak at all, in others
it is either single, double, or treble. It also differs in contour,
and, according to these differences in shape or number, naturalists

Kn Rd

TTPO TTT er

G
TMM Aci

TGP
Oe Me (

Fig. 6.—Longitudinal section through the Buccal Mass of Helix (after W.
Keferstein). .O, mouth ; 47%, buccal cavity ; 47, muscles; Rd, radula; Kz, lingual
cartilage ; @, cesophagus ; A/, jaws ; Z, sheath of radula.

have striven to form a system of classification, and none, perhaps,
more so than Moquin-Tandon and Dr. Morch. It has not, how-
ever, found as much favour with English workers as it deserves,
but on the continent it is almost universally adopted by concho-
logists, and is also, now and again, to be found referred to in
English works and papers on conchology. The student must,
therefore, make himself perfectly familiar with the terminology of
this portion of the subject, and the following synopsis is adopted
from an article communicated by Mr. Ralph Tate to the Zzze/-
lectual Observer about twenty years ago, but which contains,
nevertheless, a full explanation of the terms necessary for the
beginner to make himself conversant with.

Synopsis of the genera of British Land and Fresh-water Mollusca,
grouped according to the nature of the mandibular organ.

I.—AGNATHA (without mandibles). Zestacel/a.
II.—MonocnaTua (mandible single).

1. Oxygnatha. Mandible lunate, smooth, rostrated.
Limax, Amalia, Vitrina, Hyalina.,

2. Elasmognatha. orse-shoe-shaped, with a plate
behind. Swccinea.

3. Aulacognatha. Sides nearly parallel, striated. Aud/7-
mus, Cochlicopa, Clausilia, LBalia, Pupa, Vertigo,

24 LAND AND FRESH-WATER SHELLS.

Helix (Hi. rupestris, Hf. pygmea, Hi. rotundata, 1.
pulchella), Carychium, Physa, Planorbis (excluding
P. corneus).

4. Odontognatha. Ribbed, margin denticulated or crenu-
lated.

(a) Slightly arched, ribs numerous, bluntly denticulate
margins. Arion, Geomalacus, Helix (H. obvoluta, H.
cantiana, H. cartusiana, HZ. sericea, Hl. hispida, 1.
concinna, H. riufescens, FH. acuta).

(2) Strongly arched, ribs few. Helix (H. ericetorum,
HT, pisana, Hl. caperata, Hl. virgata, H. nemoralis,
HT. hortensis, HZ. aspersa, H. pomatia).

III. TricnatHa. Mandibles three. Zizmncea, Ancylus, Planorbis

cOTrneuUS.

IV. DicnatHa. Mandibles two, lateral. Cyclostoma, Acme,

Paludina, and the other fresh-water Gastropods.

The radula consists of a chitinous plate beset with teeth, which
as they are worn away are replaced by others from behind.
Taking a transverse row of teeth, it will be found that they vary
in different places, and it is possible to represent them by using a
formula. ‘Thus, when in each row there is a single median tooth

Fig. 7.—A segment of the radula of Neritina fluviatilis (after S. Loven).

with three teeth on each side of it, more or less closely resembling
one another, we write the formula 3.1.3. When there are addi-
tional lateral pieces of a different shape to those immediately
adjoining the central teeth, we indicate them by the figure o,

ANATOMY AND PHYSIOLOGY OF A SNAIL. 25

repeated to represent their number. Thus 0000.1.1.1.0000 is the
formula for the lingual teeth of C/z/on Stelleri. A single median
tooth, an admedian series, and a lateral series may be thus dis-
tinguished. In some Glossophora* only median teeth are present,
or large median teeth with a single small admedian tooth on each
side of it ; these are termed Rachiglossa (formula, —1.—or 1.1.1.).
In a large number of Glossophora we have three admedian on
each side and one median, no lateral pieces ; these are termed
Tzenioglossa (formula 3.1.3.). Those with numerous lateral
pieces, four to six or more admedian pieces, and a median piece
or tooth, are termed Rhipidoglossa (formula x.6.1.6.x., where x.
stands for an independent number of lateral pieces). The Toxo-
glossa have 1.o.1., the central tooth being absent, and the lateral
teeth peculiarly long and connected with muscles. The term
Ptenoglossa is applied to those Glossophora in which the radula
presents no median tooth, but an indefinite and large number of
admedian teeth, giving the formula x.o.x. When the admedian
teeth are indefinite (forty to fifty) and a median tooth is present,
the term Myriaglossa is applied (formula x.1.x.). It must be
understood that the pieces or teeth thus formulated may
themselves vary much in form, being either flat plates, or denti-
culated, hooked, or spine-like bodies” (Professor Ray. Lankester,
Art. “ Mollusca.” Eucy. Brit., vol. ix., pp. 640, 641). In some of
the Helices the total number of teeth present on one radula may
amount to more than thirty-nine thousand. The radula is sup-
ported by a subradular membrane, under which there are a pair
of odontophoral cartilages to which intrinsic muscles are attached.
The buccal mass is moved by numerous muscles. The retractor
muscle is a large sheet which passes back from its floor to be
inserted into the columella; the prvotractors are a number of deli-
cate bundles of muscle tissue, which pass from its side walls to be
inserted into the integument of the head ; the Zevazors are delicate
like the last, and arise just above them to be inserted near the
ventral tentacles; the defressors pass obliquely backwards, and
are situated just below the protractors. MacMunn has found a
colouring matter, termed myohzematin, in these muscles, and
Prof. Lankester has found that hemoglobin is present in the

* Molluscs with an odontophore and radula.

26 LAND AND FRESH-WATER. SHELLS.

buccal mass of some snails. The epithelium in the buccal mass
is cylindrical, and in some places ciliated.

From the buccal mass a narrow gullet (wsophagus) passes into
a distended portion of the enteric tract,—the cvop,—on the sides
of which are placed the saZvary glands. A microscopical examina-
tion of a section of the cesophagus presents six layers from without
inwards,—(r1) a peritoneal investing coat; (2) a layer of longitu-
dinally arranged muscle-cells ; (3) a layer of circularly arranged
muscle-cells ; (4) a lacunar mucosa layer ; (5) a layer of epithe-
lium ; (6) alining cuticle. The crop is spindle-shaped (/wszform),
with its lining membrane thrown into numerous longitudinal
folds; it is generally conspicuous on account of the yellow
character of its contents. The salivary glands are compound
glands made up of unicellular glands. They are generally two in
number, but 47. fomatia has an additional one imbedded in its
buccal mass. ‘They secrete free sulphuric and free hydrochloric
acids, which act upon the starchy matters of their food-stuffs in
the same way as the ptyalin of the human saliva. ‘They convert
the starch into sugar. This secretion is carried from the glands
by two ducts, which open into the buccal mass just above the
odontophore. ‘The glands will be seen to be lobulated, and con-
fluent with one another on the posterior and dorsal surface of the
crop.

Passing from the crop the enteric canal narrows, but soon
expands again to form the s/omach. ‘This is a simple sac, incom-
pletely subdivided into two by a longitudinal septum, and into
which the ducts of the ‘‘ A/7tteldarmdriise” open. ‘The stomach
differs in contour in different species. In some marine forms, as
Aplysia and Bullea aperta, horny processes and plates are deve-
loped, with which to triturate the food, a condition which strongly
reminds one of the “ gastric mill” of a cray-fish. In the former
of these, Ap/ysca, the wall of the stomach is thickened, and
beset with horny spines like canine teeth, and with rhomboidal-
shaped plates like molar teeth. The food, consisting of seaweeds,
after having been coarsely masticated in the buccal cavity and
crop, is pierced by these spines and afterwards pounded into a
pulpy mass by the plates. In the second of these, Lullea aferta,
there are three large plates, which are convex on the outside and

ANATOMY AND PHYSIOLOGY OF A SNAIL. 27

concave interiorly. In a third case, Bulla lignaria, there are
three plates, attached to which are strong muscles, but these
plates are calcareous, and not horny, as are those of Audlea aperta.
It will be a reminder to those who are careless, to know that these
calcareous plates in the stomach of Auw//a have -been wrongly
described as a new bivalve shell, under the name of Giwn7za. Our

Fig. 8.—Anatomy of H. Pomzatia (after Cuvier). The mantle-cavity is opened on
the left side, and the mantle is turned over to the right. The body cavity has been-
opened, and the viscera are unravelled. Cg, supra-cesophageal ganglion ; S4, salivary
gland ; 17, crop; D, intestine; Z, ‘‘ Mitteldarmdriise’’ (digestive gland, hepato-
pancreas, gland ‘of mid-intestine, liver) ; A, anus ; AZ, auricle ; C, ventricle; PZ, lung;
Zd, hermaphrodite gland invested by lobes of the ‘‘ Mitteldarmdriise ”’ ; Zd, albumi-
niparous gland ; Px, prostate; U7, female portion of the common generative duct ;
Rs, receptaculum seminis or spermatheca; Dy, muciparous glands; Ps, dart-sac ;
P, penis; #7, flagellum; J/7, retractor muscle of the penis ; SA, spindle muscle.

own fresh-water form, Zznca stagnalis, approaches the condition
of things, I think, found in Buea aperta. It has astrong stomach,

and is in the habit of swallowing pebbles from the bed of the
pond, for the purpose, no doubt, of aiding in the trituration of its

28 LAND AND FRESH-WATER SHELLS.

food. In one stomach of the animal of that species I counted
the other day no less than twenty-seven small pebbles.

The “ Mitteldarmdriise,” as the organ has been recently called
by Frenzel, is a brownish mass divided into two asymmetrical
portions, and lying in the whorls of the spire. Known in English
works as the “ver, hepato-pancreas, digestive gland, or gland of the
mud-intestine, its right lobe or portion is the larger, and is sub-
divided into three smaller lobes, from each of which a duct carries
the secretion to a common duct, which opens on the right side
of the stomach. It is grooved by the intestine, and occupies the
upper half of the first turn of the spire. The left portion, or lobe,
separated from the right lobe by four structures,—the crop,
stomach, intestine, and albuminiparous gland,—is placed in the
upper turns of the spire, and has imbedded in its substance the
hermaphrodite gland or ovotestis. It has a single duct, which opens
into the left side of the stomach, nearly opposite to the opening
of the duct of the right lobe. In microscopical structure it is an
acinous gland, the several acini of which are bound together by
connective tissue. ‘The gland substance shows a differentiation
into three kinds of cells,—calcareous cells, which are triangular, and
contain lime in combination, according to Barfurth, with
phosphoric acid ; * hepatic or granular cells, containing fat globules,
albuminous bodies, and granules which are highly refractile—the
fat globules are passed with the faeces ; ferment cells, which are
more or less club-shaped, and contain fat globules, albumen glo-
bules, and other bodies that are more or less viscous. The fat
globules blacken on treatment with osmic acid. The ferment cells
secrete an unformed ferment named trypsin, and an amylolytic
ferment. In the ‘‘ Mitteldarmdriise ” of Avion ater, Heltx aspersa,
and 7. fomatia hematin has been demonstrated ; and in the last
named of these species enterochlorophyll has been found in
addition. According to Barfurth, the secretion of the calcareous
cells goes in the main to the formation of the epiphragm. He
burnt the organ to an ash at different periods of the year, and
then quantitatively estimated the amount of lime it contained.
The average amount present in May was 20'24 per cent., in
September 25°72 per cent., and after the formation of the

* This has been opposed by Frenzel.

ANATOMY AND PHYSIOLOGY OF A SNAIL. 29

epiphragm 10°26 percent. The liver secretion is acid to litmus
paper. In Planorbis, Limnea, and Buccinum the cesophagus has
a lateral ceecal_crop appended to it. The anus terminates on the
left side of the body in Planordis, and it has a median position
in Zestacella and Doris.

The trypsin of the secretion of the “‘ Mitteldarmdriise ” converts
the proteids of the foodstuffs into peptones, so that they can be
absorbed by the enteric tract; the amylolytic ferment converts
starch into sugar, and so renders it into a condition necessary
for absorption. ‘This absorption probably goes on throughout the
whole length of the crop, stomach, and intestine, and more especially
by the epithelium covering certain conical processes of the mucosa
layer of those portions of the enteric tract. But the most interest-
ing fact in the physiology of the Mollusca is that a substance termed
glycogen has been found in most of their tissues, and especially
in the substance of this digestive gland,—the “ Mitteldarmdriise.”
This glycogen (C,H1,O;), as can be seen from its formula, is an
isomer of starch and dextrin. It is a white amorphous substance,
insoluble in alcohol and ether, and its aqueous solution has a
strong dextro-rotatory influence on polarised light. Its presence
in the tissues may be readily detected—provided the animal has
been recently killed—by testing with iodurretted potassium, with
which it gives a wine-red colour, disappearing on heating, reappear-
ing on cooling. In the Vertebrates, it has been detected in the
liver (1°5——-4 per cent.), muscles, villi of the chorion, embryonal
tissues, placenta, and the white corpuscles of the blood. In the
Mollusca, Hammersten has demonstrated that in the liver of
flelix pomatia it is present to the extent of 1°75 per cent., and
that in hibernating animals of the same species, and in the same
organ, it is decreased to the amount of 0°429 per cent. ; Barfurth
has found it in most of the tissues of Avion, Limax, Helix and
Cyclostoma ; while Blundstone has discovered it in the mesentery
of Helix.

Whence comes this glycogen, and whither is it bound? We
may get a suggestion or two regarding these questions which
we naturally ask, if we will call to our mind what is known of the
physiology of the Vertebrates in this particular, and compare it
with what has been demonstrated as existing in the Mollusca.

30 LAND AND FRESH-WATER SHELLS.

There can be little doubt that the mother-substance of glycogen
in the Vertebrates, at any rate, 1s carbohydrate food, while the
ingestion of proteid matter seems also to favour its production,
but in afar less degree. The former kind of foodstuff (starch)
is in them changed by peculiar diastatic ferments—the ptyalin of
the saliva, and the amylopsin of the pancreatic juice—into sugar,
which is taken up from the digestive tract, as such, by the radicles
of the portal vein to be carried to the liver, there to undergo, by
a process of dehydration, its conversion into glycogen. The latter
—proteid matter—is, in them, converted into peptones by the
action of the pepsin (in the presence of hydrochloric acid) of the
gastric juice, and the trypsin (in'the presence of sodium carbonate)”
of the pancreatic juice, and afterwards split up in the liver into
a non-nitrogenous portion (glycogen) and a nitrogenous portion
(probably urea). We have thus a starch diet and an albuminous
diet, producing glycogen in the liver of vertebrates. Where does
the analogy exist in the case of the Mollusca? ‘Their food is
essentially, in the majority of cases, a vegetable one, and forming
the chief chemical constituents of plants are carbohydrates and
proteids. The carbohydrates are starch, inulin, dextrin, and
sugars, including glucose, cane-sugar, and various others.
Proteids are there as protoplasm, aleurone grains, crystalloids,
gliadin, vegetable fibrin, and a native albumen which is soluble in
water, and coagulable by heat, and, in many respects, identical
with animal albumen.. And we have previously spoken of the
action, in the Mollusca, of the salivary secretion and of the
amylolytic ferment of the secretion of the ‘ Mitteldarmdriise”
in converting starch into sugar; and we have already spoken of
the action of the trypsin of the secretion of the ‘‘ Mitteldarm-
driise in the Mollusca, as converting colloid proteids into crystalloid
peptones. And that, in the Mollusca, glycogen is immediately
formed from the ingesta, has been proved by Barfurth, who found
that after three weeks’ fasting it had disappeared from the liver
of Helix, but that it reappeared in from nine or ten hours after
feeding, and by Hammersten in the decrease in the amount of
glycogen showed (already noticed) in the liver of &. pomatza,
which had hibernated in a warm room. ‘There seems, then, every
reason for us to believe, in the face of no evidence to the contrary,

ANATOMY AND PHYSIOLOGY OF A SNAIL. 31

that the mother-substance of glycogen in the Mollusca is the same
as that in the Vertebrata. What its destination in the Mollusca
may be, we have very little direct evidence to guide us to a safe
conclusion. In the Vertebrates, it is no doubt devoted to the
production of heat and muscle-energy. Broken up, in them, by
a blood-ferment again into sugar, as the exigencies of the system
demand, it is taken by the radicles of the hepatic vein to undergo
katabolic changes in the tissues. And that it is used up during
muscular contraction by them does not admit of a doubt, for it
has been experimentally proved that all the glycogen disappears
during movement. What about the Mollusca? Barfurth has
demonstrated that the quantity present in the muscles of Helix
is Inversely proportional to their activity, and should Wooldridge’s
theory that the Vertebrate blood-ferment is lecithin prove to be
a fact, we have here two things that unite together to show,
disregarding the facts we have already mentioned, that glycogeny
in the Mollusca and in the Vertebrata are far from being dissimilar,
since lecithin is present in the Molluscan blood. But, whatever
its destination inthe Mollusca may be, it is a point well worthy
of mention in connection with this, that a large amount of reserve
- material must be stored away in their tissues in some kind, if not
in the form of glycogen, for the exigencies of the system during
hibernation, and also for prolonged muscular contraction, since
Simroth has stated that a small Ae/¢x can move along when
burdened with a weight nine times its own, and Sandford has
proved that a /e/ix aspersa, weighing one-third of an ounce, can
draw along a horizontal plane a weight weighing seventeen
ounces (fifty-one times its own weight), and that another of the
same species, one-quarter of an ounce in weight, can drag a weight
of two and a quarter ounces after it when moving along a vertical
plane (nine times its own weight).

Glycogen is rather a difficult substance to prepare pure, but
the steps of the process are as follows. The organ suspected to
contain it is taken from a recently killed animal, cut up into
pieces, and plunged into boiling water in order to destroy any
ferment that may be present, then boiled for some time and
filtered. The filtrate is allowed to get cool, and dilute hydro-
chloric acid and potassio-mercuric iodide are alternately added to

32 LAND AND FRESH-WATER SHELLS

precipitate any proteids that may be present in solution, and this
is continued until no precipitate any longer obtains. Then it
is filtered—if any glycogen be present the filtrate is clear and
opalescent—and the glycogen is precipitated from the filtrate by
adding 70 to 80 per cent. of alcohol in excess. The precipitate
obtained is then washed with 60 and go per cent. of alcohol,
afterwards with ether, lastly with absolute alcohol, then
dried over sulphuric acid and weighed. Claude Bernard (born
1813, died 1878), a great French physiologist, was the first to
discover this substance in the liver-cells of the Vertebrates and
the Mollusca; he published his researches in 1857. Besides
being known under the name of glycogen, it is often spoken
of as hepatine, benardine, and zoamyline or animal starch.

THE CIRCULATORY SysTEM.—The fluid in the Mollusca which
corresponds to the blood of the higher animals is known as blood-
lymph or hemolymph. In it white-corpuscles or lymph-corpuscles
float. In /elzx the hemolymph contains a respiratory substance
termed hzemocyanin, which contains copper united with a proteid,
and turns bright blue, when oxidised; in Planorbis corneus it
contains hemoglobin. The heart is surrounded by a pericardium,
and situated near the kidney or nephridium in the dorsal portion
of the body-cavity. The pericardium communicates with the
kidney by a ciliated tube—the veno-pericardial canal or nephridial
tube. ‘The heart is composed of an auricle and a ventricle,
separated from one another by an auriculo-ventricular valve.
The aorta arises from the base of the ventricle, and immediately
divides into an anterior and a posterior aorta. The anterior
aorta passes into the prostoma under the head of the spermatheca
and the first coil of the intestine, and ends in relation with the
undersurface of the buccal mass, giving branches on its way to
the foot, crop, salivary glands, tentacles, reproductive organs and
integument, and also special branches to the supra-pedal gland
and rectum ; the posterior aorta passes into the visceral hump,
and supplies the intestine, reproductive organs, and hepato-
pancreas. There are no special capillaries, and the blood passes
from the arteries into blood-spaces,—the ¢vansition vessels of
Nalepa,—from whence, after supplying nutriment to the tissues,
it is returned to the heart by way of the various venous sinuses.

ANATOMY AND PHYSIOLOGY OF A SNAIL. 33

On cutting open the pedal sinus the openings of these transition
vessels into this sinus can be observed. ‘There are four venous
sinuses, two fedal sinuses, a visceral or marginal sinus, and a
pulmonary sinus or circulus venosus pulmonis. The pedal sinuses
run along the foot, one on each side; the marginal sinus runs

Fig. 9.—Nervous and circulatory systems of Paludina vivipara (after Leydig).
F,, tentacle ; Oe, cesophagus ; Cg, supra-cesophageal or cerebral ganglion, with eye ;
Pg, pedal ganglion with adjacent otocyst ; Vg, visceral ganglion; Pg, infra-ceso-
phageal or pharyngeal ganglion; A, auricle of heart; Ve, ventricle ; Aa, posterior
aorta ; Ac, anterior aorta; V7, veins; Ve, afferent vein ; Gv. gill.
from the apex of the spire to end in the cércu/us venosus pulmonts,
a very large sinus which surrounds the base of the mantle cavity.
From the last named sinus numerous afferent vessels—the a/erent
pulmonary veins—arise to form a plexus on the wall of the mantle
cavity, and from these efferent vessels—the efferent pulmonary
vetns—carry the blood to the nephridium, where they break -up
into a plexus—the veal plexus—the venules of which join together
to form a renal vein, which unites with a vein—the pulmonary
vein—formed by the coalescence of a large number of efferent
pulmonary veins. The pulmonary vein enters the auricle; it has
been seen by Nalepa to pulsate rhythmically in Zonztes algirus.
The marine snail, Had/zotis, has its heart somewhat similar to that
organ in Anodonta cygnea. Its auricle is divided into two cavities,
and its ventricle is pierced by the rectum. In /éssurel/a and in

2

34 LAND AND FRESH-WATER SHELLS.

Chiton this division of the auricle also obtains. In Zonites algirus,
according to Nalepa, and in Avion ater, according to Jourdain,
the transition vessels open into the venous sinuses by infundi-
bular orifices. In Zoxttes algirus Nalepa has demonstrated a
network of nerve-fibres in the auricle, ventricle, aorta, and larger
vessels, but ganglia are rare. Haller has demonstrated ganglia
in the cardiac walls of the marine snails, Zvochus, Haltotis, and
Fissurella. The arteries and arterioles in Zovwites algirus are
lined by an endothelium. ‘The venous system is represented in
part by the ccelome (body-cavity), in part by vessel-like spaces,
the walls of which are formed of homogeneous connective tissue
with scattered nuclei, but which are not lined by epithelium.” In
Chiton, Nerita, Neritina, Turbo, Emarginula, Fissurella, and in
Parmaphorus the ventricle is pierced by the intestine.* In
Janus and Lmarginula, besides the genera already mentioned,
there are two auricles. In many Prosobranchs the heart is
connected to the pericardium by fibrils. In Apdysia the com-
mencement of the aorta is strengthened by muscle-fibres, a
condition of things which, as Professor Owen says, resembles the
bulbus arteriosus of fishes. In some forms, as /ontolimax and
Phyllirhoé, there are no vessels except the aorta; in Rhodope and
Lntoconcha there are no specialised vessels at all. In FPatel/a the
“transition vessels ” are separate from the celome. In Aaliotis,
Fissurella, and Emarginula the ventricle is double. Vulpian has
found that nicotine, curare, and digitalis inhibit the heart’s beat
in about five or six minutes, just as they do in the higher
Vertebrates. According to Ashford the pulse of Hedix hortensis
and Hyalina cellaria beats 12 to 14 per minute at 42 to 44° Fahr.,
9 to 11 at 37 to 38° Fahr., and 4 to 8 at 26 to 33° Fahr.

THE RESPIRATORY SySTEM.—In the Pulmogastropoda breathing
is carried on through the pulmonary aperture which leads into the
mantle-sac formed by an expansion of the body-wall (mantée).
The walls of the mantle are very vascular, the vessels running in
it being those already mentioned,—the afferent and efferent pul-

* Landsberg is opposed to the statement generally made that the intestine
perforates the heart in Weritina fluviatilis and Turbo rugosus. In the former,
according to his researches, the intestine passes between the heart and the
nephridium ; in the latter it pierces the pericardium only.

ANATOMY AND PHYSIOLOGY OF A SNAIL. 35

monary vessels, the pulmonary vein, and the circulus venosus
pulmonis. External respiration can be readily performed then
by this vascular network. In the branchiate Gastropoda respira-
tion is performed by a cfenzdium or gill, the water containing air
being admitted in the majority of cases by an anterior siphon, and
expelled by a posterior siphon. These gills can be well seen in
Paludina vivipara. Cyclostoma elegans is an example of a bran-
chiate becoming a pulmonate; it has lost its ctenidium, and
respiration is now carried on by the walls of the pulmonary sac.
It is the only English example of the PNEUMOCHLAMyYDA, a class
proposed by Professor Ray Lankester to contain all those terres-
trial Mollusca in which the ctenidium has aborted, and respiration
carried on by means of a lung. aludina vivipara has a ctenidium,
and consequently it belongs to an allied class termed the Hoto-
CHLAMYDA in which the ctenidium is present in the adult. The
passage from the branchiate to the pulmonate form is well seen
in the genus Ampullaria, where a ctenidium is to be found on the
left side of the mantle-cavity, while the right side, which is separated
from the left by a fold, is extremely vascular in character. The
floor of the mantle is formed by a sheet of muscle tissue. Inspira-
tion is effected by a contraction of this muscular layer, which
bulges up when at rest into the mantle cavity just as our dia-
phragm does in our chest cavity; expiration is effected by the
return of the muscular layer to a state of relaxation.

A somewhat similar condition of things present in Ampullaria
has been found by Semper, it is interesting to note, in a terrestrial
Crustacean, Bivgus latro. According to Sabatier, the blood is
driven, in Ampullaria, to the gills when the lung is collapsed, and
to the lung when the gills are collapsed, by means of a valvular
spur situated at the junction of the afferent vessel of the gills, and
the afferent vessel of the lung. <A few years back a good deal of
discussion was taking place in the Continental magazines about
the respiration of the Zzmncaa in deep water, and during winter
when the ponds are covered with ice, the outcome of which is the
interesting fact that under such circumstances they do not respire
atmospheric air direct, but admit water to their pulmunary cavity
instead.

‘Tue Nepuripium.—The kidney or nephridium is situated in

36 LAND AND FRESH-WATER SHELLS.

the mantle-cavity between the pulmonary vein and the heart, and
communicates with the pericardium by a ciliated canal,—the reno-
pericardial canal or nephridial tube,—so that the pericardial cavity
is In communication with the exterior through the ureter or duct
of the kidney. The ureter runs alongside of the rectum in
ffelix, and opens near the anus into the mantle-cavity ; in Avion
the kidney has “‘a simple round opening.” ‘The kidney is made
up of two parts, one thin-walled and sacculated, the other
yellowish, and possessing a lamellated structure. The excretion
contains ammonium and calcium urate; and in /yalina free
uric acid and guanin in addition to these. If minutely examined,
the orifice of the duct of the kidney in //e/7x will be seen to be
carried as a groove—the excretory groove—over the anus, ending
near the respiratory aperture.

Ture NERvous SysteM.—Lying round the cesophagus is a cord
of nervous tissue—the circum-wsophageal mass—which is divided
into that portion which lies above the cesophagus (supra-wsopha-
geal ganglia) and that portion which hes below the cesophagus
(sub- or infra-wsophageal ganglia). ‘The supra-cesophageal ganglia
are two in number, and are united together in the middle line by
a band of nerve-fibres (commissure); from them nerves pass to
nnervate the lips, tentacles, and the buccal mass. ‘The infra-
cesophageal ganglia are divided into two portions—an anterior
portion (pedal ganglia) and a posterior portion (v7scero-pleural
ganglia)—by the passage of the anterior aorta through the centre
of its mass. The pedal ganglia give branches to the muscular
substance of the foot; the viscero-pleural ganglia send branches
to the body-wall and viscera. A miscroscopical examination of a
ganglion shows it to consist of nerve-cells generally unipolar, some-
times bipolar and multipolar, placed round a central mass of nerve-
fibres derived from them, and arranged in a reticulated manner.
To this central mass Leydig has given the name of Punkt-substanz.

The xzerve to the tentacle arises from the supra-cesophageal
ganglion with the labial nerves, and ends at the summit of the
tentacle by a knob which consists of nerve-cells and nerve-fibres,
surrounded by a muscular sheath derived from the retractor
muscle of the tentacle, and which is thought to be olfactory in
function, since on excising it on both sides the snail no longer

ANATOMY AND PHYSIOLOGY OF A SNAIL. 3/

recoils from strong smelling liquids such as turpentine, which it
invariably does when one or both are present. In Limnea stag-
nalis and FPlanorbis the infra-cesophageal ganglia are orange or
red-coloured, and very pretty indeed. The nervous system of
Limnea stagnalis well dissected out is the prettiest dissection I

Fig. 1o.—a, Nervous system of Haliotis (diagrammatic after Sprengel); Cg, cir-
cum-cesophageal mass; Pg, pedal ganglion; Plg, pleural ganglion (commissural
ganglion); Ag, abdominal ganglia; O and O’ olfactory organs; Pe, pedal cord;
S and S” lateral nerves; Br, gills ; 4, nervous system of Limnea, (after Lacaze-
Duthiers).

have ever seen. The circum-cesophageal mass in the large
Tritons is almost cartilaginous to the touch.

THE OLFacrory OrcANns.—The sense of smell may exist in the
supra-pedal gland, the dorsal tentacles, or in the lobate processes
around the mouth. An osphradium is to be found in Limnea,
Planorbis, and Physa consisting of ganglion cells in relation with
a depression in the mantle-chamber above and behind the respira~

38 LAND AND FRESH-WATER SHELLS.

tory aperture. A nerve supplies it in Zzmncea from the right
visceral ganglion: in Planorbis and Physa the nerve comes from
the left visceral ganglion. In the Helices the osphradium is
apparently absent, but a nerve has been described by Sarasin in
fLelix personata which arises from the right visceral ganglion, and
ends near the pulmonary orifice in a collection of ganglion cells.
The same nerve has been found in Limax cinereo-niger, Succinea
amphibia, Bulimus detritus and Bulimus decollatus, but the
ganglion cells are absent.

THe AUDITORY OrRGANS.—Before ever the auditory organs were
dissected out the late Dr. Grant surmised their existence, for he
could not but think that the sounds emitted by Z7itonéa arbor-
escens under water, were intended to be heard by its fellows.
Siebold first discovered the auditory organs or, as they are
generally termed, the ofocysts. They are a pair of minute white
bodies in very close relation with the pedal ganglia, and in
Paludina are movable by muscles. Each consists of a connective
tissue capsule containing fluid, anda large number of calcareous
granules (o/o/¢‘hs) which are in constant motion. ‘These otoliths,
disturbed by the sound waves from a sounding body, strike upon
the nerve filaments of the auditory nerve, which thus communt-
cates a wave of change to the supra-cesophageal ganglion, the
result of which is the perception of sound by the animal.

THE ORGANS OF SiGHT.—We have previously considered the
relation which the eyes may bear in different species to the dorsal
tentacles. The eye consists of a cornea, lens, or vitreous body
(Carriere), and a retina composed of pigmented and non-pigmented
cells. The lens or vitreous body is structureless, and fills the
whole of the cavity of the eye; the cornea is composed of connec-
tive tissue, with a layer of transparent cells on its outer surface
The optic nerve is derived from the nerve to the tentacle in the
STYLOMMATOPHORA ; in the BASOMMATOPHORA it is an indepen-
dent nerve. Snails cannot accommodate for long distances, since
they cannot distinguish objects till within a quarter of an inch
from the eyes. In Chiton and Vermetus the eyes are absent.
In fatella the eye is cup-shaped. The eye can be invaginated
into the body by the retractor muscle of the tentacle which is
inserted into the columella, .

ANATOMY AND PHYSIOLOGY OF A SNAIL. 39

THE REPRODUCTIVE ORGANS.—The reproductive organs of the
typical Pulmonate Gastropod may be well divided into three
groups, a male group, a female group, and a group common to
both the male and female group. The male group contains the
penis sac, vas deferens, prostate, and flagellum ; the female group is
made up of the oviduct, dart-sac, receptaculum semints, albumint-
parous gland, and jfinger-shaped glands ; the group common to
both the male and female portions contains the hermaphrodite
gland or ovotestis, the hermaphrodite duct, the common generative
canal, and the cloaca or
vestibule. These various
parts will be readily seen
at a glance in the accom-
panying figure of the
generative organs of our
largest English land-snail,
Flelix pomatia. The
principal organ is the
hermaphrodite gland or
ovotestis situated in the
left lobe of the ‘ Mit-
teldarmdriise,” and con-
sisting of numerous fol-
licles connected together
by connective tissue. The
ova and spermatozoa are
formed from the wall of
the follicle and from {
identical cells, but they Fig. rr. —Reproductive organs of H. fomatia. Zd,

are developed at different hermaphrodite gland; Zg, its duct ; Ed, albuminipa-

- rous gland ; Od, common generative canal ; Vd, vas
times,—the former from deferens ; P, protrusible penis ; 77, flagellum; “7s,

the cells on the outer ‘eceptaculum seminis; J, finger-shaped gland; Z,
1 - spiculum amoris in the dart-sac; Go, common gene-

wall, the latter from its rative opening (after Baasen).

more central portion. A

spermatozoon is a filiform body—the filamentous portion being

known as the /az/—with an enlargement at its anterior extremity

(head); an ovum is a rounded cell without a distinct outer coat,

as in the higher animals, and it consists of protoplasm con-

40 LAND AND FRESH-WATER SHELLS.

taining a more or less rounded structure (germznal vesicle), which
in its turn encloses a larger, more refractile body (germinal spot).
It is a primitive undifferentiated cell pure and simple; the
germinal vesicle represents the nucleus, the germinal spot the
nucleolus. We shall have to refer to this ovum more in par-
ticular directly, when we come to consider the chief steps in the
development of the snail.

The ducts of the follicles of the ovotestis unite to form a duct
common to them all, lined with non-ciliated squamous or columnar
epithelium—the /ermaphrodite duct—which leaves the gland,
courses through the albuminiparous gland, and at last, after
receiving the duct of that gland, leaves it to form the common
generative canal, The common generative canal is composed of
the vas deferens and oviduct united together. ‘The lumen of the
vas deferens is in communication with that of the oviduct by
numerous slits in the dividing membrane, and around the vas
deferens a somewhat fluffy-looking mass will be seen on a minute
examination—the so-called frostate. This common generative
canal, however, at last divides into a longer independent portion
—the vas deferens proper—which belongs to the male organs of
generation, and into a shorter independent portion—the oviduct
—which constitutes part of the female generative organs. The
common generative canal is lined with a ciliated epithelium, and
its walls are glandular, the independent portion of the oviduct is
ciliated likewise, but in the vas deferens proper the cilia are
absent. The albumen or albuminiparous gland is a greyish-white
or yellowish tongue-shaped organ, situated between the stomach
and the right lobe of the ‘‘ Mitteldarmdriise.” It is a racemose
gland, the ducts of the acini of which open into a common duct
—the duct of the albuminiparous gland—which has its epithelium
ciliated, and which opens into the hermaphrodite duct just before
it leaves the gland as the common generative canal. There may
be two accessory albumen glands, as in Zzmmnca stagnalis, or one,
as in Limnea peregra.

The vas deferens proper runs between the female generative
organs and the buccal mass, lies on the back of the crop, and
terminates in the penis sac. It gives off a long coiled diverticu-
lum—the /lagellum—previous to its termination. Sometimes

ANATOMY AND PHYSIOLOGY OF A SNAIL. 4I

this flagellum is given off from the base of the penis. The
penis sac during copulation is exserted ; attached to it is a
retractor muscle. ‘The flagellum, with the posterior part of the
penis, secretes the spermatophore or capreolus. This is a body
formed of mucus with its edges folded inwards, so as to form a
groove in which spermatozoa becomes lodged, and more or less,
as it were, glued together into a mass. When the flagellum is
absent the spermatophore may be formed in the vas deferens
(Hyalina) or in the penis (Avzoz). The flagellum is absent in the
American Helices. In Zoligo vulgaris, and in many other forms,
a special pouch is developed in the vas deferens for the
spermatozoa ; this is known as (Veedham’s pouch. According to
the recent researches of Ashford the flagellum of TZestacella
haliotidea has a special retractor muscle.

The oviduct, like the flagellum, gives off in its course a
diverticulum—the sfermatheca or ~receptaculum seminis—the
function of which is to receive during coition a spermatophore
derived from another snail. This structure consists of a globular
head—the Swammerdamian vesicle—lying near the albumen
gland, and of a duct—the duct of the spermatheca. In Helix
aspersa, and in other members of the genus to which it belongs,
there is an additional diverticulum given off which ends near the
aorta, and may possess a globular head. Below the point of
origin of the spermatheca the oviduct is generally spoken of as
the vagina ; this runs forwards to open side by side with the
penis into a common genttal cloaca or vestibule. In the genera,
Limnea, fPlanorbis, and Ancylus the male aperture (fenial
aperture) is distinct from the female aperture (os vagine), the
former being the more anterior of the two. The consequence
is that, anatomically, at any rate, self-fecundation is possible in
them, and this has been actually observed in Liamnca auricularta.
Into the vagina open two structures,—the mucous or finger-
shaped gland, and the dart-sac. The former of these consists of
a pair of tufted tubular glands, which secrete a highly refractile
fluid that is poured out when coition takes place. The dart-sac
is a pear-shaped organ, containing in its interior a peculiar
spicule, known as the dart or spiculum amoris, which is of a
calcareous nature, except in Vitrina elongata, where it is chitinous.

AZ LAND AND FRESH-WATER SHELLS,

The dart varies in shape in different species. It is to be found
only in the He/ices* and in the slugs Agriolimax maculatus and
Tebennophorus. Myr. Ashford has made the admission that the
dart, in his thinking, is not thrust out of the body; but he is
wrong, for it is forcibly ejected from one snail to the other before
they engage in co/tus, and it is not a rare thing, when doing
field work, to pick up one of them from out of the grass. He
based his statement on the fact that when dissecting a dart out
of its sac it is always to be found connected at its base to the
posterior end of the lumen of that. organ ; the mistake is here,
since the dart is secreted continuously by cells in the posterior
end of the sac, and this causes it to simulate an appearance as
if attached. The function which this dart serves in the economy
of the snail has not, as yet, been thoroughly investigated. My
friend, Professor J. Bland Sutton, suggested to me that it is an
organ of cuticular irritation, and I find that Simroth holds the
same view; but I cannot see any good reason to make this
hypothesis at all stable, for, if so, why is it not a constant feature
in the anatomy of the majority of snails? To me, the most
probable and the most feasible view, as yet, has been advanced by
another friend of mine, Mr. W. E. Collinge of Leeds. He believes
that in it we see the vestige of a structure which was once
constant in all snails, and which was used in former times as a
weapon of defence. Mr. Collinge is still collecting together facts
to support his view, and we shall all await the result with interest.
In H. hispida, H. riufescens, H. plebeta, and Hf. villosa there are
two dart-sacs, each containing a spiculum amoris. The Gas-
tropoda, with the exception, perhaps, of Zzmax Jevis, are, as is
seen from the foregoing description, moncecious (Gr., moz0s,
single ; ozkos, house) or hermaphrodite (Gr., Hermes, Mercury ;
Aphrodite, Venus) animals. The generative act consists essentially
in an exchange of spermatophores, which are said, in H. fomata,
to resolve in about ten days after the receival by the animal.
The spermatozoa set free by this resolution fertilise the ova in
the oviduct as they are descending from the ovotestis. By the
land-snails the eggs are laid singly in the earth or under stones
and logs of wood; by the pond-snails they are laid in an

* Tt is rare in the American Helices ; so are the finger-shaped glands.

ANATOMY AND PHYSIOLOGY OF A SNAIL. Asi:

elongated or ovoidal mass (damental mass), which is fastened to
a stem or a leaf of an aquatic plant, or often to stones and
bricks that lie on the bed of the pond or river. The Auliné
make a nest for their eggs by cementing together leaves of
trees. Laludina vivipara and P. contecta are ovoviviparous among
water-snails ; Helix rupestris, a few species of Clausilia and Pupa,
a Vitrina and an Achatinella are viviparous among land-forms.
The different processes which the egg undergoes in its develop-
ment cannot be described here in detail, because they are of too
complicated a character to be well understood by the beginner.
Enough, however, will be stated to render the reader familiar
with the more striking changes, and should he wish to advance

Fig. 12.—Some stages in the embryonic development of Planorbis (after C> Rabl).
4, optical section through a segmenting ovum (24 segments). 2%, polar bodies; 7%,
segmentation cavity, 4, stage with four mesoderm cells viewed from the vegetative
(lower) pole ; A7s, mesoderm cells ; En, endoderm ; Zc, ectoderm, c, oblique optical
longitudinal section through the stage with four mesoderm cells, d, older embryo in
which the shell-gland has shifted to the right, Sdv, shell-gland ; s, Shell ; O, mouth ;
D, alimentary canal ; R, commencing radula ; Sf, apical plate (thickening of przoral
lobe) ; Oc, eyes; of, otolith ; NV, primitive kidney; /’z, velum.
farther into the subject he may consult the embryological
text books in general use, such as Balfour’s ‘“ Comparative
Embryology,” and Haddon’s “Introduction to the Study of
Embryology,” or the article ‘ Mollusca” by Professor Ray
Lankester in the sixteenth volume of the last (ninth) edition of
the Encyclopedia Britannica. Taking Limnea stagnalis as
a typical instance, the ovum first divides into two and then

into four portions, each division being preceded by the division

44. LAND AND FRESH-WATER SHELLS.

of the germinal vesicle. ‘Then from the upper surface of these
four spheres which are known as macromeres, numerous smaller
spheres (micromeres) are budded off. These go on increasing
in number to a large extent, macromeres, and micromeres being
produced by the division of those previously existing. Mean-
while a cavity is formed in the centre of their mass,—the segmenta-
tion cavity,—and the macromeres, becoming invaginated or
tucked into the segmentation cavity, form a double-layered
embryo, the external wall (ectoderm) being formed of micromeres,
the internal wall (exdoderm) being made up of macromeres.
This stage is known as the gastrula-stage, and the opening
produced by the invagination of the macromeres, the d/astopore.
This blastopore closes as the larva advances in its development,
and the place where the future mouth and anus are to be formed
becomes marked off by invagi-
nations of the ectoderm occurring
at the anterior and _ posterior
ends of the closing slit as the
stomodeum and proctodeum re-
spectively. ‘The embryo now be-_
comes oval in contour and sur-
rounded by a circlet of cilia,—
the “‘ Zrochosphere-stage”’ of Lan-
Fig. 13.—Older larva of a Gastropod (after kester,—which divides the body
Coeenbaun) S helg 2 foes Ye into two unequal hemispheres, a
the closure of the shell opening. smaller, which develops into the
visceral mass, and a larger, which
becomes the foot. The ciliated circlet then becomes the ve/um
—a structure identical with the disc of a Rotifer—the foot grows
larger, and becomes bilobed, the mantle and shell become de-
veloped, the tentacles begin to appear, and the snail passes
from this ‘‘ veléger stage” into a definite molluscan condition,
the whole process of development from the egg to the mature
state occupying a period of time varying from twenty to thirty
days.

CHAPTER » FIL
THE ANATOMY AND PHYSIOLOGY OF A FRESH-WATER MUSSEL.

TakE a shell of the Swan Mussel (Anodonta cygnea).

(A) Examine its outer surface. Note -—

t. Its oval form, blunt at its anterior, but produced at its
posterior extremity.

2. The wmbo, a small blunt prominence near the dorsal border.

3. The Zines of growth, running concentric to the umbo.

4. The “igament, uniting the two valves together along their
dorsal margins. ‘‘ The relations of the ligament to the shell
valves show that strictly speaking the valves ought to be regarded
as parts of a continuous structure. The dorsal region of this
structure does not undergo calcification, or only to a very slight
extent, inasmuch as the economy of the animal requires that it
should remain flexible. It is an adaptation of an originally
univalve shell.”

(Bs) Examine its inner surface. Note :—

1. The anterior adductor impression, near the anterior end of
the shell.

2. The anterior retractor impression, a small area continuous
with the anterior adductor impression.

3. The protractor impression, about 3th of an inch posterior to
the inferior portion of the anterior adductor impression.

4. The fosterior adductor impression, an oval depressed area
near the posterior end of the shell.

5. Lhe postertor retractor impression, a small depression con-
tinuous with the posterior adductor impression.

6. The pallial fine, an even curved line running parallel to the
inferior margin of the shell. In Azodonta this line is even
throughout its whole extent,-and the shell is said to be dztegri-

40 LAND AND FRESH-WATER SHELLS.

palliate ; those shells in which the pallial line is not evenly
described, but forms asinus in relation with the posterior adductor
impression are said to be sznufalliate.

Fig. 14.—The anatomy of a Mussel, and the internal markings of its shell.

7. The Lines of shifting of the muscles, numerous lines running
from the different impressions towards the umbo.
8. The Ainge, a longitudinal ridge running along the dorsal

N \ \ \y
SYS
\

\ A\\

Fig. 15.—Right valve of the shell of Cytherea showing internal markings.

portion of each valve. The absence of teeth in the Anodon
shell ; in Unio, Spherium, and Pisidium teeth obtain. The teeth
consist of three sets: cardinal teeth situated below the umbones,

ANATOMY OF A FRESH-WATER MUSSEL. 47

anterior lateral teeth in front of them, and fosterior lateral teeth
behind them. WDreissena polymorpha may, or may not, possess
teeth.

g. The /égament connecting the two valves of the shell together.
In Anodonia, according to F. Miiller, this ligament consists of an
outer part and an inner part, the former being continuous with
the epicuticula of the shell, the latter having a distinct ridge—the
homologue of that portion produced into teeth in Unio, Spherium,
and /isédium, where it borders the nacreous layer. ‘This ridge,
_ like the teeth, gives attachment to muscles from the foot. The

~ ==
SSS BEE a
Z

————

Via . AIRARAMARES ola ol -
Py ane nmaneeteetbocc
. TOTO tii

mas | UU

mt ae

Fig. 16.—Vertical Section through the shell and mantle of Axodonta (after Leydig).
Cz, cuticle, S, prismatic layer ; B/, nacreous layer; //’, external epithelium of mantle ;
Ld, connective tissue substance ; £f”, internal epithelium of mantle.

outer part is laminated; the inner part is radially striated, and
consists of radial fibres made up of two different kinds of
substances which refract light differently.

In microscopic structure the shell may be said to consist of
three layers,—an eficuticula or periostracum,* a prismatic layer,
and a zacreous layer. The periostracum is thin, horny, laminated,
and consists of conchiolin; the prismatic layer consists of
numerous polygonal prisms united together by conchiolin and

* Often erroneously called the epidermis.

43 LAND AND FRESH-WATER SHELLS.

placed obliquely to the surface of the shell; the nacreous layer
consists of calcareous laminz alternating with organic lamine.
It is formed by the cells of the general mantle surface, the
epicuticula by cells near the mantle-edge, and the prismatic layer
by cells posterior to those forming the epicuticula. Muller
believes the shell to be alive, growing by intussusception, or the
deposition of particle between particle ; while Tullberg seems to
hold the view that the organic matter is produced by fibrillation
of the cells of the mantle. ‘The calcareous portion of the shell
consists in the main of calcium carbonate, with, sometimes, traces
of calcium phosphate, alumina and silica. About one-third of the
animals of Anodonta cygnea which I have examined were the
subjects of what I may term the fearly diathesis. Pearls are
formed by depositions of nacre round a grain of sand which. has
gained admission into the pallial cavity, provided, I would say,
that the organism of the animal be predisposed, since sand-
grains, by the very nature of their habitat, must gain admission
into the mantle cavity of all mussels indiscriminately, while it is
only in about a third that the grains of sand become surrounded
with nacre. It isa point well worthy of mention that when pearls
occur they are generally situated in and around the pericardium.

The shell of Spherium corneum has no prismatic layer, and the
nacreous layer has a reticulated structure. The shell is canilicu-
lated, and into each canal a process of the mantle extends. The
structure of the shells of our other Lamellibranchs are worthy of
investigation, and I would recommend it as a study to those of
my readers more especially ‘interested in the anatomy of the
Mollusca.

Examine the animal within its shell. . Note :—

1. The mantle or pallium divided into two lobes, a right and a
left. -Its thickened ventral border, the pal/zal muscle.

2. The gidls or ctenidia, lying internally to the mantle, two on
each side of the body.

3. The ladial palps, two pairs of triangular folds in front of
the gills.

4. The foot and visceral mass, a \arge ploughshare-shaped mass
lying between the right and the left mantle-lobes.

5. The anterior and posterior adductor muscles passing from

ANATOMY OF A FRESH-WATER MUSSEL. 49

one valve of the shell to the other. In Azodonta they are equal
in size (Isomya) ; in Dretssena polymorpha the anterior is smaller
than the posterior adductor muscle (Heteromya). Some Lamelli-
branchs have only one adductor muscle, and are then called
““monomyaries ;” those with two adductor muscles are termed
“ dimyartes.”

6. The anterior and posterior retractor pedis muscles, near the
anterior and posterior adductors.

7.. The protractor pedis muscle, behind the anterior adductor.

8. The pallial muscle, attaching the mantle to the pallial line.

9. The zxhalent aperture, bounded with tentacular fringes at
the hinder end of the body.

10. The exhalent or cloacal aperture, Geteniedhintely dorsal to the
inhalent aperture.

Thus Keferstein’s analogy of the general structure of a Lamelli-
branch to a book is appropriate. The cover of the book is the
valves, the back is the hinge-line, the fly-leaves are the mantle-
- lobes, the second and third pages on each side are the gills, and
the interior of the book is represented by the visceral mass and.
foot.

THE MANTLE, MANTLE-CAVITY, AND GILLs.—The mantle-
lobes are symmetrical. They are continuous with the body-wall
above, below they are free. The epithelium on their internal
surfaces is ciliated. Between them lies the mantle or pallial
cavity, divided by the base of the gills into an upper or swfra-
branchial chamber, and a lower-or infra-branchial chamber. In
this pallial cavity lie the gills, foot, labial palps, and the greater
part of the visceral mass. ‘The gills or ctenidia consist of a pair
of plates lying on each side of the foot. Each plate is made up
of a descending and an ascending lamella, the descent and ascent
being from a ridge on the body-wall termed the gz//-axis. Each
lamella is composed of a number of gill-filaments which have
become fused together so as to form a trellis-work-like structure.
It will be best to trace these gill lamellz from the gill-axis. From
the gill-axis two descending lamellze proceed, one to form the
inner lamella of the outer gill, the other to form the outer lamella
of the inner gill. These, descending for some distance, at last
turn sharply upon themselves, and the inner lamella of the outer

4

ye) LAND AND FRESH-WATER SHELLS.

gill thus becomes the outer lamella, and the outer lamella of the
inner gill the inner lamella,—-ze., of course, of their respective
gill-plates. The outer lamella of the outer gill-plate becomes
united by concrescence with the mantle, the inner lamella of the
inner gill remains free as a slit through which the infra-commu- —
nicates with the supra-branchial chamber. Thus, “ regarding,
then ”—as Professor Lloyd Morgan in that most practical of all
recent text-books, ‘ Animal Biology,” says,—“ the gills as com-
posed of a greater number of filaments with descending and
ascending moieties, and we are justified by comparative morphology
and development in so regarding them, we have to note the large
amount of fusion or concrescence of parts.

1. The inner surfaces “of adjoining filaments have become
united by a membranous expansion, the lamellar membrane,

Fig. 17.—The Organ of Bojanus Fig. 18.—Diagrammatic Section
in diagrammatic section. of a Mussel.

/

perforated with oval fenestrae or windows. Thus the ascending
and descending filaments respectively come to form ascending and
descending lamelle.

2. The two lamelle of each gill become fused by interlamellar
junctions, occurring in the inner gill at intervals of about twenty
filaments, and in the outer gill at intervals of seven or eight
filaments.

3. The ascending lamella of the outer gill is concrescent with
the mantle along its whole length.

ANATOMY OF A FRESH-WATER MUSSEL. SI

4. The ascending lamella of the inner gill is concrescent
anteriorily with the foot.

5. The ascending lamelle of the inner gills are concrescent
with each other posteriorily.

6. The union of the gill-axis with the body-wall may be partly
due to concrescence.”

The surfaces of the gill-filaments are covered with cilia, which
may be divided into three groups, viz.,—those with the shortest
cilia (/atera/), those with medium-sized cilia (/fronta/), and those
consisting of a single row of cells which have very long cilia
(lateral frontal). The lashing of these cilia produces a current o1
water, which passes in the supra-branchial chamber by the inhalent
aperture, and, after finding its way into the infra-branchiai chamber
through the fenestre in the gill-lamellee and the slit between the
visceral mass and the inner gill, leaves the body through the
exhalent aperture. Professor Ray Lankester thinks that perhaps
the gills and labial palps are the homologues of the prze-and post-
oral ciliated bands of the Echinoid and Ophiurid larva, Plufeus,
or the Zornaria larva of Lalanoglossus. Doubtless, as Peck
thinks, the current of water produced by these cilia subserves
the function of alimentation as well as that of respiration.

THE Dicestive SystEM.—The mouth is situated below the
anterior adductor muscle, and is bounded by a pair of membranous
folds on each side—the J/adial palps—which lessen in size the
nearer they are to the mouth. The labial palps at the mouth are
confluent on either side, and their free edges encircle a groove,
known as the c7//ated groove, which runs into the mouth-aperture.
We have just referred to what Professor Lankester has suggested
regarding these palps taken together with the ctenidia ; it would be
as well to mention that Lovén has suggested that the palps are
the remains of the velum. The cesophagus is short but spacious,
and leads back into a dilated chamber of an irregular shape—the
stomach—which lies in the substance of the digestive-gland in a
position in the body immediately anterior to the pericardium.
The intestine commences on the floor of the stomach by a well-
marked pylorus, runs downwards and backwards towards the
posterior end of the body in intimate relation with the generative
gland, then doubling on itself, it passes again downwards and

52 LAND ‘AND FRESH-WATER SHELLS.

backwards to the mid-ventral region, where it redoubles upon
itself, and after running for a little distance pierces the anterior
end of the pericardium, from whence it runs as a straight rectum
through the ventricle of the heart, ending by an anus on the
dorsal side of that posterior portion of the supra-branchial chamber
which is sometimes spoken of as the cloacal chamber. ‘The
rectum has a well-marked typhlosole running its whole length, the
function of which is probably to increase the absorptive area.
In the walls of the intestine of most Lamellibranchs, or in an
appended ceecum, a peculiar crystalline style is often found, the
formation and function of which have been made the recent
subjects of research by Hazay. It is an albuminoid body, which
probably acts as a stopper to the pylorus. Its formation takes
place from spring to autumn, and is generally completed by
October by the differentiation of a gelatinous mass in the
stomach, which is apparently food-material. The style is, how-
ever, absorbed during the winter months, and the question naturally
occurs to us whether or not we must look upon it as reserve
nutrient material. The cells lining the intestinal tract are ciliated.
The liver, digestive gland, or hepato-pancreas lies between
the anterior adductor muscle and the pericardium, and on either
side of the stomach, into which it pours its secretion through
several ducts. It secretes trypsin and a diastatic ferment, and
the extract of the gland is active in either an acid, a neutral or
an alkaline medium. There are no calcareous cells, the cells
present being granular and ferment cells.

THE ORGANS OF CIRCULATION.—The heart consists of two
auricles and a pear-shaped median ventricle, situated in a fer7-
cardium, which communicates with the glandular portion of the
nephridium by several veno-pericardial apertures. The pericardial
cavity is pierced by the intestine, the ventricle by the rectum.
Between each auricle and the ventricle there is an auriculo-ven-
tricular valve consisting of pocket-shaped segments, which only
admit the blood from the auricle into the ventricle. From the
anterior end of the ventricle the anterior aorta arises and runs
along the dorsal surface of the rectum ; from its posterior end the
posterior aorta arises and runs along the ventral surface of the
rectum. ‘The anterior aorta passes into the visceral mass behind

ANATOMY OF A FRESH-WATER MUSSEL. 53

the anterior retractor muscle, and divides into a visceral and a
pedal artery, the former of which supplies
blood to the digestive and generative organs,
the latter to the foot, besides giving off a

labial branch to the labial palps, and a pal/al

’vanch to the mantle and anterior adductor

muscle, The posterior aorta gives branches 5, 45. piagram of the
to the mantle, body-wall, and posterior ad- heart of a Mussel.

ductor muscle. These arteries break up

into numerous lacunar spaces, from whence the blood finds its
way into the vera cava which lies under the pericardium. From
this vessel the blood passes to the organs of Bojanus, in which
the blood-vessels form an irregular plexus, and thence by the
afferent branchial vessels to the ills, where it becomes oxidised,
losing carbon dioxide and gaining oxygen. From them, the now
arterialised blood is carried by the efferent branchial vessels to
the efferent branchial sinus, which expands to form the auricle.
The direction which the blood takes may then be arranged in a
aa form, thus :—

. Ventricle.

. Anterior and posterior aorte.
Arterioles and lacunar spaces.
Vena cava.

Organ of Bojanus.

. Gills.

. Aluricles:

- -Ventricle.

The blood or hemo-lymph consists of a colourless plasma, in
which colourless corpuscles (deucocytes) float. The extension of
the foot for the purposes of locomotion is due to a congestion of
the lacunar spaces in that organ. The vein which conveys the
blood from the foot is surrounded by a muscular sphincter, which,
when the animal wishes to walk, contracts, and so prevents any
return of blood, while the heart continues at the same time to
pump blood into the lacunar spaces. A peculiar plexus of vessels,
known as the pericardial gland or Organ of Keber, exists near
the anterior end of the paeaba cavity. Its function is un-
known.

Car AN © N

54 LAND AND FRESH-WATER SHELLS.

THE EXcRETORY OrGANS.—The excretory organs, organs of
Bojanus, or nephridia, are situated just beneath the pericardium.
They excrete guanin, not uric acid. Each is composed of a
glandular part, communicating in front with the pericardial cavity,
and of a non-glandular muscular part or vestzbule, which communi-
cates with the fellow of the opposite side by the z”ter-rvenal aperture,
and with the exterior by a small pore—the ev/ernal renal aperture

Fiz. 20.—The Organ of Bojanus in diagrammatic plan.

—which opens into the-supra branchial chamber dorsal to the
generative opening. The glandular portion consists of numerous
lamellae, and on these Kollmann has recently described blind
ciliated funnel-shaped openings which may in Anxodonta be
present to the number of two hundred.

THE Nervous SysteM.—The nervous system consists of three
pairs of ganglia—the cerebral or supra-wsophageal (which according
to Sprengel represents the cerebral plus the pleural ganglia in the
snail), the peda/, and the osphradial, olfactory, or parieto-splanchni¢c
ganglia, with numerous commissures. The cerebral ganglia are
situated at the base of the labial palps, and are united together
over the mouth by an énter-cerebral commissure ; they are triangular
in shape, and supply branches to the palps, mantle, gills, and
neighbouring muscles. From these ganglia two cords, forming
the cerebro-pedal commissures, run downwards and backwards to
the pedal ganglia in the foot. The pedal ganglia are situated at.
the junction of the visceral mass and the foot ; they are orange-
coloured bodies giving branches to the foot. It is generally
stated that the nerve to the otocyst comes from the pedal ganglia,
but according to the recent researches of Simroth, it must be con-
sidered as arising from the cerebro-pedal commissure.

ANATOMY OF A FRESH-WATER MUSSEL. 55

From the cerebral ganglia, two cords also proceed as the cerebro-
splanchnic commissures through the substance of the nephridium

Fig. 21.—Diagram of the nervous Fig. 22.—a, Ganglionic or nerve
System of a Mussel. cell with nucleus; 4, nerve-fibre
showing contained granules.

to two yellow parieto-splanchnic ganglia on the underside of the
posterior adductor muscle. These ganglia send branches to that
muscle, and to the foot.

Tue ORGANS or SpectAL SenseE.—Many years ago Siebold
discovered in the foot of Spherium corneum a ‘‘ small sacculus,”
which contained “a cretaceous nucleus of a crystalline structure
performing remarkable oscillatory movements,” and this he very
properly regarded “as a rudimental organ of hearing.” In
Anodonta this auditory organ or ofocyst is situated near the pedal
ganglia, and it has its nerve from the cerebro-pedal commissure.
Lankester thinks that an organ described by him as the osphradium,
consisting of a layer of ,elongated epithelial cells in relation with
the osphradial ganglion, subservient to the sense of sniell, while
the osphradial ganglion itself is considered by some as a Co-
ordinating centre for sensations received from the inhalent current.
The labial palps may be organs of taste ; the general surface of
the animal is sensitive to touch.

THE REPRODUCTIVE ORGANS.—With the exception of a few,
such as Pisidium and Spherium, all the Lamellibranchs are
dicecious, a condition of things which was first made known by
Leuwenhock. Avxodonta, however, is sometimes found to be
moncecious. ‘The generative gland is a racemose gland situated
in the visceral mass. The ovary cannot well be distinguished
from the testis, except upon a microscopical examination, although

56 LAND AND FRESH-WATER SHELLS.

the former portion is more reddish than the latter. The genital
aperture opens just below the orifice of the ureter. The ova in
the female do not pass directly out of the body, but congregate
in large numbers between the two lamellz of the outer gill, where
they develop into peculiar larval forms—which were considered

Fig. 23.—A, Glochidium-larva still within the egg; B, Glochidium viewed from the side
showing the teeth on its valves.

parasites of the mussel by Rathké and Jacobson—known as
Glochidia. Each valve of a glochidium-shell is shaped like an

Fig. 24.—Shell of Glochidium widely opened, showing the single adductor muscle.

equilateral triangle, with the apex incurved, and produced into a
sharp saw-edged tooth. A single adductor muscle is present ;

ANATOMY OF A FRESH-WATER MUSSEL. 57

the foot is small and slightly developed, and in its place two fila-
ments—the dyssal filaments—are seen projecting from the larva.
In this form the embryo is ejegted from the gill of its brood-
mother into the water. Then, sinking down to the bottom, the
shell gapes widely, for the single adductor muscle is not strong
enough to keep the valves together. Swimming by the flapping
of its valves, when it becomes a little more developed, the young
Anodon attaches itself by means of its byssal filaments to either

Fig. 25.—Young Mussels on the tail of a fish.

the gill-covers, lips, or fins, of a fish,—especially Zeucescus and
Gobio,—and fixes its sharp teeth into its body. Remaining for a
time in this parasitic condition, the single adductor muscle and
byssal threads atrophy, and in their place the anterior and pos-
terior adductors become developed, and the foot more developed.
Changes go on until the larva has become like the parent from
which it originated, and then the young Anodon loses its hold,
drops down into the bottom of the water in which it exists,
and commences the every-day life of its mother (wvéde, Shel/-
Collector's Handbook for the Field, p. 29). In Spherium and
Pisidium development takes place in a_ special brood-pouch
developed near the inner gill-plate. The young bivalve is
nourished by a secretion from the walls of this pouch, just as the
young Anodon is nourished by a secretion from the gills. As
was first recorded by Garner, it is not a rare thing to find the
young of Spherium corneum in the body of the adult animal.

——

Fig. 26.—A Group of Water-Snails.

Planorbis corneus,

Paludina vivipara,

Limnea stagnalis.

CHAPTER IV.

THe CLasses, ORDERS, FAMILIES, GENERA, SPECIES, AND
VARIETIES OF BRITISH LAND AND FRESH-WATER SHELLS.

(AQUATIC. ) |
Crass L—MALACOZOA ELATOBRANCHIA.

SHELL a bivalve, the two valves of which are united along their
dorsal margin by a ligament. Body, oval, headless; mantle
bi-lobed ; foot tongue-shaped, sometimes provided with a byssus.
Respiration performed by gills.

ORDER I.—LAMELLIBRANCHIATA.

Gills four in number, leaf-shaped, arranged in pairs on each side
of the body between the visceral mass and the mantle.

Family 1.—Spheertide.

Shell equivalve, subglobose ; hinge with lateral and cardinal
teeth. Body with one or two siphons at its anterior end.

1. Sphzrium.—Shell nearly equilateral. Mantle with two
prominent contracticle siphons.

(2) Shell yellowish-brown or brownish, finely striated, suborbi-
cular ; umbones blunt, nearly central; ligament small, not visible
externally ; muscular impressions faint; hinge strong with a
double cardinal tooth in each valve, and two triangular-shaped
teeth in the right valve and four teeth in the left. Length 6 lines ;
breadth 4 lines; thickness 34 lines. Ditches, marshes, ponds,
canals, and rivers. Generally distributed. S. corneum}

1 y. flavescens, paler, not so large, more globular; v. mzcleus, smaller,
nearly spherical ; v. Péscdiodes, shell subtriangular, slightly more produced at

its posterior slope, ligament just visible externally, transverse striz coarser ;
v. minor, shell smaller, nearly globular.

60 LAND AND FRESH-WATER SHELLS.

(6) Shell brownish-green, or yellowish-horn colour, strongly
striated, oval, ventricose ; marked sometimes with two or three
dark bands; umbones blunt, central; ligament conspicuous ;
muscular impressions distinct ; teeth as in S. corneum. Length
to lines; width 7 lines; breadth 5 lines. Canals and sluggish
streams. S. rivicola.

(c) Shell pale grey, compressed, oblong, faintly striated ;
umbones small, central ; ligament long, narrow, visible externally ;
cardinal teeth very small ; muscular impressions distinct. Length
4 inch; width ths inch; thickness ; inch. Ponds and rivers.
Local. S. ovale,

(2) Shell yellowish-white or ashy, more compressed than 5S.
corneum, saubrhomboidal ; umbones narrow, central, capped with
the nucleus of the shell ; ligament narrow, slightly visible ; muscular
impressions indistinct, teeth smaller and shorter. Length 4 lines ;
width 3 lines; breadth 13 lines. Ditches, marshes, ponds, canals,

and rivers. Generally distributed, but local. S. lacustre.?
2. Pisidium. — Shell inequilateral. Animal with one
siphon.

(2) Shell triangular, tumid, deeply grooved concentrically,
whitish-grey or pale brown; umbones blunt, rather prominent ;
ligament short, narrow, conspicuous; teeth as in Spherium.
Length 4 lines; width 3 lines; thickness t4 lines. Canals, ponds,
lakes, and rivers. P. amnicum.®

(2) Shell triangular, very tumid so as to be cuboid in shape,
greyish-white, finely striated; ligament short, scarcely visible ;
umbones pointed, prominent; muscular impressions distinct.
Length 2} lines; width 1? lines. Canals, ponds, ditches, and
sluggish streams. P. fontinale.*

(c) Shell oval, compressed but swollen, yellowish-white or
greyish-horn colour, thin, finely striated ; umbones blunt, short,

2 vy. rotunda, shell rounder, flatter, yellowish-green; v. Ryckholtiz, shell
small, globular, triangular, umbones pronounced ; v. Brochoniana, shell larger,
flatter, umbones smaller.

3 y, striolata, smaller, wrinkles more pronounced ; v. /eviuscula, larger,
wrinkles demi-effaced.

‘ v. cinerea, larger, flatter, striz fainter; v. pe/chel/a, more glossy, strongly
grooved, umbones less acute ; v. Hezslowana, with a plate-like appendage near
the umbones.

| CLASSES, ORDERS, ETC. 61
nearly central; ligament short, not visible from the outside.
Length 13 lines; width 14 lines. Marshes and ditches.

P. pusillum?
(d) Shell suborbicular, in the upper part rather tumid, in all
the other parts compressed, thin, very glossy ; ligament short, not
visible from the exterior ; muscular impressions distinct. Length

jsth inch; width +th less. Ponds and pools. P. nitidum.®
(2) Shell very small, oblong, thin, ventricose, deeply striated,
yellowish-white or pale horn-coloured ; umbones blunt, prominent,
very excentric ; ligament nearly invisible; muscular impressions

indistinct. Ponds and pools. P. roseum.

Family I1.— Unionide.

Shell large, oblong, equivalve, inequilateral. Mantle lobes free

Fig 27.—Unio Pictorum.

all round, except at the posterior edge, where they form two
orifices, which are somewhat awl-shaped.

5 vy. ventrosa, shell slightly more trigon-shaped, more ventricose, v. gvandrs,
much larger, v. ob¢wsalis, shell smaller, much more tumid, umbones sharp and
pronounced.

5 vy, splendens, lemon-coloured.

62 LAND AND FRESH-WATER SHELLS.

3. Unio.—Shell firm, solid, cardinal teeth large, lateral teeth
lamelliform.

(2) Shell oblong, ovate, solid, brown; epidermis smooth ;
umbones prominent, rugose, excentric ; anterior teeth high, conical,
strong. Length 3 inches; width 3 inch. Canals, ponds, rivers.

U. tumidus.!

(2) Shell oblong, ventricose, wedge-shaped, greenish-yellow
marked with brown in lines of growth; ligament parallel to lower
margin, longer than in U. ¢umidus ; umbones not so prominent
nor so rugose as in U. ¢umidus ; anterior teeth arched, much
compressed ; hinder teeth of left valve small or evanescent.
Length 2 to 3 inches. Ponds, lakes, and slow running streams.

U. Pictorum.§

(c) Shell black-brown, elongated, ovate, thick, heavy, strongly
striated, very compressed; umbones incurved, generally eroded,
excentric ; cardinal teeth small, slightly compressed, thick, sub-
triangular, conical, the posterior one of the left valve much
developed. Length 54 inches ; width 23 inches; breadth 1 inch.
Among the gravel and small stones in the shallows of quick
running rivers or mountain torrents. U. margaritifer.®

4. Anodonta.—Shell thin, hinge without teeth.

(a) Shell very large, oval, thin, dull green, more or less anaes :
lines of growth large; umbones small, plaited; ligament long,
parallel to lower margin ; posterior side gaping and produced into
a rounded cuneiform. point. Length 24 to 4 inches; breadth
3 tog inches. Lakes, ponds, canals, and muddy rivers.

A. cygnea,®

(6) Shell smaller than 4. cygnea, oval, compressed behind,

7 y. radiata, thinner, greenish with yellow rays, hinge-line nearly straight ;
v. ovalis, wedge-shaped, dark olive-brown.

8. y. radiata, yellowish with green rays; v. J/aéior, broader, shorter,
yellowish-brown ; v. curvirostris, smaller, shorter, bent, olive-coloured ; v
rostrata, slightly more elongated, lanceolate behind, brownish.

9 vy, Roissyi, less arched above, not sinuous below, larger posteriorily ;
sinuata, broader in proportion to length than type, yellowish- brown, Ae
margin incurved towards the middle.

1 y. ventricosa, shell larger, more elongated, more ventricose ; v. radiata,
larger with yellow rays ; Vv. Zellensis, yellowish-brown, broader, upper and
lower borders nearly parallel; v. Aa/dida, light yellow or fawn colour ; v.

CLASSES, ORDERS, ETC. 63
brown-olive, glossy ; umbones straight, excentric ; umbonal region
compressed, rugose ; ligament short, prominent, forming an angle
with the lower margin; upper margin curved and raised into a
sort of a crest, length 24 inches; breadth 34 inches. Small rivers,
canals, and ponds. A, anatina}"

Family II1.—Dreissenide.

Shell boat-shaped, equivalve, furnished with a byssus ; umbones
placed at the extreme end; hinge with small teeth or edentulous ;
ligament internal.

5. Dreissena.

(az) Shell mussel-shaped, triangular, keeled in the centre of
both valves, olive or yellowish-brown, marked transversely with
zigzag streaks of purple or dark brown; ligament long, narrow,
and fitting into a groove in the hinge of both valves; umbones
incurved, small, placed at the anterior end ; lower margin incurved,
length 1 to 1? inch. Canals, lakes, and rivers.

D. polymorpha.

Crass II.—MALACOZOA GASTROPODA.

Shell univalve or none. Body with a distinct head, and two
or four tentacles; eyes situated at the extremity of the dorsal
tentacles or at the base of them; respiration effected by gills or
lung.

ORDER I.—PECTINIBRANCHIATA.

Shell spiral, external, operculated. Respiratory organ consisting
of a single pectiniform gill.

intermedia, oblong, feebly arched below, moderately arched above, obliquely
truncated behind ; v. zostrata, oblong-oval, upper margin forming a dorsal
crest.

vy. complanata, oval, very compressed, brown, umbones close to anterior
margin ; v. vadzata, marked with yellow and green rays; v. ventricosa, very
tumid in the middle and umbonal region, larger, more solid, marked with green
and yellow rays ; v. mznzma, shell smaller, not quite so broad, blackish. (By
some conchologists Asodonta anatina is considered to be a variety of A. cygnea,
but a recent examination of over seven hundred specimens does not warrant
me in doing likewise.)

64 LAND AND FRESH-WATER SHELLS.

Family 1.—Neritide.

Shell semiglobose; spire small, flat, excentric, mouth semi-
circular ; operculum shelly, with a plate-like appendage on its
under side.

1. Neritina.

(2) Shell ovate, solid, glossy, yellowish or brownish, with white
purple, brown or pink chequerings ; spire short, lateral, composed
of three whorls, the last one being excessively disproportionate ;
mouth semilunar; operculum semilunar, yellowish, bordered with
orange, and with a strong, raised, grooved spire placed at one end
of its lower surface. Length 3 lines. In canals and rivers with
stony bottoms. N. fluviatilis 3?

Family I1.—Paludinide.

Shell cone-shaped, ventricose; mouth oval; operculum con-
centrically striated. Body oval; eyes sessile or placed on
pedicels at the base of the tentacles; gills internal.

2. Paludina.—Animal ovoviviparous ; eyes placed on pedicels ;
operculum horny.

(a) Shell conically oval, ventricose, dull yellowish-green with
three brown bands on the body whorl, and two upon each of the
preceding whorls ; umbilicus none or represented by a slit ; mouth
an irregularoval. Length 1 to 12ths inch. Ponds, lakes, canals,
and slow rivers. P. vivipara.

(2) Shell conoid, very ventricose, brown olive marked with
three brownish bands on the body whorl, and with two on the
preceding whorls; spire blunt or sharp: sutures very deep;
umbilicus distinct, narrow, deep ; mouth nearly circular. Length
t to 13ths inch. Canals and stagnant waters. P. contecta.!

3. Bythinia.—Animal oviparous ; operculum shelly.

(a) Shell ovoid, somewhat conical, glossy, thin, solid, yellowish-
horn colour, semi-transparent ; whorls six, convex, the body-whorl

2 v. cerina, straw-yellow, unicolor; v. zzgrescens, black or blackish ; v.
undulata, with some transverse dark bands; v. ¢v¢fascéata, with three spiral

dark bands.
8 y. albida, white; v. wnzcolor, bandless; v. atro-purpura, black, which

when viewed by transmitted light is purple.
My. virescens, greenish, unicolor,

CLASSES, ORDERS, ETC. 65

large ; mouth oval, angulated above ; umbilicus none; operculum
oval, angulated above, closely fitting. Length } inch. Streams,
ditches, canals. B. tentaculata”

(4) Shell conoid, swollen towards the base, thin, subtransparent,
yellowish-horn coloured; whorls four to five, tumid, separated
by a deep suture; mouth nearly circular, less angulated above
than in B. ¢tentaculata ; umbilicus small, distinct ; operculum nearly
circular. Length 3 inch. Ditches, canals, and sluggish rivers.
More local than B. ¢entaculata. B. Leachii.

4. Hydrobia.—Operculum horny, thin; eyes placed on
tubercles.

(a) Shell ovoid, subopaque, thin, yellowish-horn coloured ;
whorls five to six, very convex; sutures deep and grooved ;
umbilicus represented by a narrow chink ; mouth oval ; operculum
oval, nucleus lateral. In ditches between Greenwich and Wool-
wich which are flooded by the tide. 1, similis.

(5) Shell a lengthened cone, thin, glossy, yellowish-horn
coloured ; whorls six to seven, convex; sutures not grooved ;
mouth oval; umbilicus smaller than in ZA, similis.

fT. ventrosa.™

Family III.—Valvatide.

Shell conoid, more or less depressed ; mouth cireular ; oper-
culum horny. Body spiral, with two tentacles, provided with a
long plume-like gill which is protruded when the animal is
crawling ; eyes situated on the inner side of the base of the
tentacles.

5. Valvata.

(2) Shell globular, thin, solid, light horn-coloured, whorls five
to six, rounded, body-whorl very large ; spire obtuse, compressed ;

' vy. albida, white; v. fulva, tawny, glossy; v. ventricosa, more tumid,
globular-conical in shape, white; v. zovata, reddish with one or more white
lines or bands; v. froducta, less tumid, in shape an elongated cone; v.
_ excavata, whorls more rounded, suture much deeper ; m. decollatum, with the
apex decollated ; v. Aad/zda, shell very pale horn coloured ; m. scalariforme, spire
scalaria,

6, v. albida, white ; v. elongata, smaller, spire more produced. .

“ y, pellucida, clear white, nearly transparent ; v. meczor, smaller, spire
shorter ; m. decollatum, spire decollated.

5

66 LAND AND FRESH-WATER SHELLS.

mouth circular, with a complete peristome; umbilicus deep ;
operculum circular, greyish-white. Length 7+ inch. Lakes,
ditches, canals, and rivers. V. piscinalis.'8
(5) Shell flatly coiled pale horn coloured, glossy ; whorls
five, the last one very large; mouth circular with a continuous
margin; umbilicus large and open, exposing the interior con-
volutions ; operculum round, reddish-horn coloured. Diameter
zoth inch. Lakes, ponds, canals, and ditches. V. cristata.

OrDER JJ.—PULMONOBRANCHIATA.

Shell generally spiral and external, but sometimes (Limacida)
rudimentary and internal, or wanting. Body spiral, generally
non-operculated, but sometimes with an operculum ; respiration
effected by means of a lung.

Family 1.—Limneide.

Shell spiral or hood-shaped ; mouth without teeth. Tentacles
two ; eyes sessile.

6. Planorbis.—Shell orbicular, flat, coiled nearly in the same
plane; mouth semi-circular; umbilicus distinct ; non-operculated.
Tentacles two in number, very long ; eyes sessile ; foot oval, short.

(a) Shell quoit-shaped, depressed, yellowish-horn coloured,
glossy ; whorls four with two to five curved transverse plates
inside the last whorl, which appear as whitish lines when viewed
from the exterior ; periphery bluntly carinated ; umbilicus narrow,
deep. Diameter tth inch. Ponds and slow streams. Local.

P. lineatus.8

(2) Shell quoit-shaped, thin, glossy, yellowish-horn coloured,
more or less reddish ; whorls four to five, the outer whorl being
without septa as in P. /éneatus, and very large in proportion to the
rest, covering one half of the preceding whorl, and bluntly keeled
in the middle of its periphery; spire not so much sunk as in P.
Zineatus ; umbilicus small, shallow. Diameter 23 lines. Ponds
and ditches on aquatic plants. P. nitidus.

8 vy. depressa, more depresssed, umbilicus large; v. albina, white or
whitish; v. fzszt//a, smaller, striz, stronger whorls four and a half; v.
acuminata, spire produced, apex sharp.

v. alvina, milk-white, transparent.
99 y. albida, white ; v. mznor, smaller.

CLASSES, ORDERS, ETC. -
(c) Shell quoit-shaped, thin, rather concave above, rather convex
below, not glossy, dull light brown or grey, subtransparent ;
whorls three, the outer whorl bluntly and indistinctly keeled on
its periphery, and strongly marked with transverse ridges in line
of growth; mouth oval; umbilicus large. Diameter ;/,th inch.
Ponds and ditches on aquatic plants. P. nautileus.”®
(2) Shell convex above, concave below, thin, whitish, trans-
parent, finely striated longitudinally, and marked with fine close-
set raised circular strize which are clothed with deciduous bristles ;
whorls five; mouth roundish-oval ; umbilicus large. Diameter
zg inch. Lakes, ponds, and stagnant water. P. albus,”
(e) Shell convex above with a central depression, concave
below, brownish-horn coloured, smooth, glossy ; whorls five to
six, more convex than in P. albus ; mouth nearly circular ; suture
well defined; umbilicus large. Diameter 2 lines. Ponds,
marshes, and lakes. Very local. P. parvus.” (= P. glaber.)
(f) Shell concave above, flat below, ov the reverse, thick, horn-
coloured ; whorls five to six, rounder and with the keel not so
well pronounced as in P. a/bus ; mouth roundish; peristome often
white ribbed; umbilicus wide, shallow. Diameter, } inch.
Shallow and stagnant waters, sluggish streams. Common.
P. spirorbis,?8
(g¢) Shell very flat, concave above, flat below, thin, glossy,
brownish-horn coloured, transparent; whorls six to eight, the
outer whorl sharply keeled on its lower margin ; mouth rhombic,
compressed ; umbilicus large, shallow. Diameter 3ths inch.
Shallow and stagnant waters. Moderately common.
Pi nore 2

“vy. crista, transverse ridges more pronounced, periphery deeply notched
or crested by them.

*“\ vy. Draparnaudi, more closely striate in line of growth; periphery dis-
tinctly keeled ; umbilicus larger. (This species is often found covered with
dirt, and requires to be well cleaned in order to show its characters.)

vy. compressa, more concave below, depressed iw the centre only on the
upper side, whorls rounder and not increasing so quickly.

* vy. albida, white; v. ecarinata, smaller, light green, keelless, one whorl
less than usual.

** v. compressa, thinner, flatter, keel more distinct. and sharper, and placed
nearly in the middle of periphery.

68 LAND AND FRESH-WATER SHELLS.

(2) Shell nearly flat above, rather convex below, yellowish-horn
coloured, thin, glossy ; whorls five to six, the outer whorl being
sharply keeled in the middle line of its periphery; mouth obliquely
oval, somewhat angular; umbilicus small. Diameter 3 inch.
Stagnant waters and sluggish rivers. Local. P. carinatus.”°

(7) Shell slightly concave above, flattish, with a central con-
cavity below, striolate, brown-horn coloured ; whorls five to six,
rapidly enlarging, with the periphery strongly keeled below ;
suture deep; mouth rhombic, rounded in front, often ribbed in-
ternally ; umbilicus large, shallow. Diameter ?ths inch Ponds,
canals, slow rivers, and ditches. P. complanatus.*®

(j) Shell reddish-brown, very tumid, glossy, nearly opaque ;
whorls five to six, rounded above and below; periphery not
keeled ; mouth semilunar; umbilicus broad, shallow. Diameter
4 to 1 inch. Canals, streams, marshes, and ponds. Somewhat
local. P. corneus.”"

(k) Shell nearly flat above with a deep concavity in the middle,
very convex below, solid, opaque, yellowish or brown-horn colour ;
whorls eight, compressed ; suture deep ; mouth crescent-shaped,
very narrow; umbilicus large, deep. Diameter ;4,ths inch.
Ponds, ditches, and lakes. P. contortus.*

(7) Shell flattish, dull, very convex below; whorls two to two
and a half, with the periphery of the outer whorl angulated ;
mouth large, squarish, and much expanded; umbilicus abruptly
contracted, small, deep. Diameter ;4,th inch. In canals round
Manchester and Burnley. Imported. P. dilatatus.

7. Physa.—Shell spiral, thin, polished ; spire s¢w7stral, non-
operculated. Animal with two long tentacles, with the eyes at
their base ; mantle very large so as to cover part of the shell.

(a) Shell fusiform, thin, yellowish or reddish-horn coloured,
glossy, semi-transparent ; whorls six to seven, rounded; suture

*5 vy, albida, pellucid white; v. dzsciformis, yellowish, flatter, thinner, keel
more prominent and sharp.

26 y, albina, whitish or colourless ; m. ¢evebrzm, whorls dislocated from one
another, and elevated into a spiral cone; v. vhomdbea, smaller, more convex
above, with a deep concavity below, keel blunt.

27 v. albina, perfectly white.

*8 vy, albida, nearly white; v. excavata, much depressed, sunken above.

CLASSES, ORDERS, ETC. 69

shallow ; mouth oval-lanceolate. Length } to ?ths inch. Ponds,
ditches, and slow-running streams. More or less local.
P. (Aplecta) hypnorum.?9

(5) Shell oval, thin, glossy, semi-transparent, pale greyish-horn
coloured ; whorls four to five, tumid, the last one occupying #ths or
4ths of the shell ; suture deep ; mouth oblong and wider and larger
in proportion than in P. hypuorum. Length 4 inch. Running
brooks, canals, ditches, and sluggish rivers. Common.

P. fontinalis.®

(c) Shell an elongated ovoid, ventricose, glossy, finely striated
longitudinally, light horny or whitish in colour; whorls three,
the last one 2ths of the total height of the shell ; suture moderately
deep; apex sharp; mouth obliquely and narrowly oval, acute
above. Height 4rd to $rds inch. In one of the lily tanks in
Kew Gardens. Imported. P. acuta,

8. Limnzea.—Shell oval, thin, translucent; mouth oblong ;
columella with an oblique plait; non-operculated. Animal with
two short triangular tentacles bearing the eyes at their base ; foot
oval.

(a) Shell oval, globular, amber or yellowish-horn coloured, thin,
transparent ; whorls three to four, inflated, the last one forming
nearly the whole of the shell; spire slightly produced; suture
rather deep; mouth oval. Mantle partly covering the shell.”
Length $ inch. Ditches, ponds, and lakes. Very local.

L. glutinosa.*!

(d) Shell ovate, thin, fragile, glossy, pale amber-coloured, glossy,
whorls three to four, convex, the body whorl very large; spire
sunk within the last whorl; suture shallow; mouth pyriform,
large. Length 54 lines. In asmall alpine lake on Cromaglaun
Mountain, Killarney, Ireland. L. involuta.

(c) Shell oval, last whorl swollen, thin, glossy, yellowish-horn

* v. cuprella, copper-coloured, whorls six, convex, the last one far exceeding
‘in size the rest put together, mouth oval, contracted above; v. major, larger,
more coloured, height 10 to 13 mm; m. decol/atim, spire decollated.

°° vy. albina, milk-white ; v. 0b/omga, spire considerably produced ; v. 7z/laza,
larger, more ventricose ; v. czr/a, spire extremely short ; m. dextrorsum, spire
dextral.

1 y, mucronata, not quite so globular, spire more produced,

{

70 LAND AND FRESH-WATER SHELLS.

colour; whorls five, convex, the body-whorl very large; spire
raised and sharp at its apex; mouth large, oval, more than half
the length of the shell. Length } to 1 inch. Stagnant waters
and slow running streams. Common. L. peregra.™
(d) Shell globosely ovate, glossy, yellowish-horn coloured, semi-
transparent ; whorls four to five, the last one very much swollen
and occupying 3ths of the shell; spire short, acute ; mouth roundish
oval, vastly expanded, oblique. Length 1 inch. Lakes, ponds,
canals, marshes, and sluggish rivers. Moderately local.
L. auricularia.®®
(c) Shell elongated, ovate, oblong, thin, greyish-white, horn or
brown-coloured ; whorls six to eight, striated in line of growth,

SSS
(fi il
(Ny \

\ »
[ i \\\ \
| \\ \ \\ .

Fig. 28.—Limnea stagnalis.

® vy, Jabiosa, smaller, outer lip remarkably expanded and reflected; v.
ovata, ampullaceous, glossy, whorls very convex, spire acute and very short,
suture deep, aperture obliquely produced, 4ths the length of the shell; v.
acuminata, resembling v. ovata but has the spire more produced and the mouth
smaller; v. Burnett’, spire exceedingly short, nearly truncate, intorted ; v.
nitida, larger, slightly transparent, fauve, coloured ; v. so/emza, ventricose,
whorls rounded, spire short, fauve, subtransparent ; v. succinecformis, shaped
like a succinea, whorls four; v. z¢ermedia, rather compressed towards front
margin, thinner, spire more produced, mouth expanded.

8% y, albida, smaller, thinner, white, spire shorter, striz less distinct ; v.
reflexa, outer lip much reflected ; v. magna, larger, aperture narrower, outer

CLASSES, ORDERS, ETC. 7%

the body-whorl occupying nearly #ths the length of the shell ; spire
acute, tapering ; mouth oval, large. Length 13 to 2 inches. In
stagnant and slow-running waters. Common. L. stagnalis,*4
(7) Shell conical, tapering, thick, opaque, dull brown ; whorls
six to seven, convex, the last whorl occupying $rds the length of the
shell; spire produced, acute; suture rather deep, circled by a
narrow white line; mouth ovate, outer lip marked with brown
or violet. Length 3 to ?ths inch. Ponds, marshes, and lakes.
Common. L. palustris.*°
(g¢) Shell oblong-oval, turreted, pale brown or yellowish-horn
coloured, rather glossy; whorls five to six, convex, deeply
separated from one another ; spire produced ; apex acute ; suture
very deep; mouth ovate, oblong; umbilical cleft distinct. Some-
what resembles L. palustris. Length } inch. Marshes, ditches,
pools, and muddy streams. Common. L. truncatula.*®
() Shell tapering, an elongated cone, thin, glossy, horn-
coloured or brownish; whorls seven to eight; mouth elongate,
ovate, not above 3rd the length of the shell, provided with a white
internal nb; umbilical cleft very minute. Length 1 inch. Ponds
and ditches. Local. L. glabra."

margin nearly parallel to the columella which is straight, the upper edge reach-
ing the commencement of the spire which is sharp; v. acz¢éa, smaller, more
oblong, having the last whorl and mouth proportionably narrower.

3 vy. fragilis, smaller, narrower, thinner, amber-coloured ; v. /adzata,
dwarfed, with the outer lip thickened and reflected ; v. voseo/abiata, slightly
narrower, brown-black, mouth bordered interiorly with rose-violet ; v. e/egazluda,
nearly scalariform, suture deep.

*® vy. corva, larger, swollen, opaque, blackish, violet-coloured within ; v.
allida, white; v. olesa, very tumid; vy. comzca, conic, greyish-white, suture
deep, umbilical cleft present ; v. ¢zzcta, shorter, broader, light-brown, mouth
purplish ; v. /acunosa, with flattenings, depressions, and protuberances; v.
elongata, slightly larger, slightly narrower, opaque, brown, spire much produced ;
m. decollatum, spire decollated.

6 y, albida, smaller, milk-white; v. major, larger, ashy, more tumid ; v.
ventricosa, more bellied, spire short, peristome without swelling ; v. 2707,
smaller, horn-coloured ; v. e/egans, much larger, more solid, more slender,
greyish-white, marked with coarse spiral ridges, spire more produced, suture
oblique, outer lip thickened.

37 vy, major, much larger ; v. elongata, more produced, so as to alter the
relative proportions of length and breadth ; m. decollatum, spire decollated.

72 LAND AND FRESH=-WATER SHELLS.

g. Ancylus.—Shell conical, oblong, limpet-shaped; apex
pointed and bent to the right; spire dextral or sinistral. Animal
with two cylindrical tentacles, with the eyes at their base; foot
large.

(a) Shell dextral, conoid, thin, yellowish-grey or horn-coloured ;
apex recurved ; mouth ovate. Height }to 3th inch. Streams and
rivulets. Common as far north as Aberdeen. A. fluviatilis.*®

(4) Shell sinistral, oblong, horn-colour tinged with yellow or
green, thin, glossy, compressed at the sides; apex acute, sub-
central; mouth somewhat oblong. Length 7 inch. Lakes,

ponds, canals, and sluggish streams. Somewhat local.
A. lacustris.*®

(TERRESTRIAL. )
Family 11.—Limacide.

Shell placed under the mantle, granular or shield-like. Body
united in its whole length with the foot beneath, there being
no visceral hump; tentacles four, cylindrical, the dorsal pair
bearing the eyes; mantle shield-like.

to. Arion.—Shell consisting ot calcareous granules. Mantle

Fig. 29.—Arion ater.

3 y, capulotdes, elevated, very convex anteriorily and laterally, nearly convex
behind, aperture oboval; v. a/dida, milk-white, striae finer; v. gzddosa, slightly
elevated, extremely convex, subgibbous in front, convex laterally, nearly straight
posteriorly, apex obtuse, aperture oboval ; v. costafa, whitish or greyish, striz
well marked.

% v. albida, milk-white ; v. compressa, rather larger and considerably broader
and flatter. ‘

CLASSES, ORDERS, ETC. ries

shagreened, not striated concentrically ; respiratory orifice placed
on anterior half of mantle; tail provided with a slime gland.

(a2) Body varying in colour, coarsely tuberculated, rounded in
front, attenuated behind ; tentacles black, bulbs much swollen ;
margin of foot marked with transverse black lines; slime yel-
lowish. Shell none, or consisting of loose granules. Length 2
to 5 inches. Type black. Woods, gardens, and hedge banks.
Common. A vater?

(2) Animal smaller than A. ater, marked with longitudinal grey
bands; mantle with a band down its middle and one round its
margins ; margin of foot red, orange, or yellow; slime yellowish.
Shell .consisting of calcareous granules cemented into an oval
mass. Length 1 to 1+ inches. Woods, hedges, gardens.
Common. : A. hortensis.“1

(c) Animal cylindrical, reddish-brown, with two lateral faint
blackish bands; mantle very convex, paler than back, with two
lateral black bands; tentacles blackish; back somewhat keeled
in its hinder portion and finely scaled ; pulmonary aperture nearly
median ; foot grey, marked with small transverse black lines ;
slime saffron-yellow. Shell a few loose granules. Length 1} to
23 inches. Woods and damp places. A. subfuscus.

(7) Animal whitish-grey ; back blackish with lateral bands ;

keel well pronounced in young individuals, but becoming more and
more obsolete as the slug becomes adult, and represented then
by a pale line ; foot whitish. Length 1}inches. Woods, gardens,
fields. Common. A. Bourguignati.
- itr. Geomalacus.—Shell solid, unguiform, concentrically
striated. Body capable of great extension ; mantle finely sha-
greened ; tentacles short, eyeless ; respiratory orifice placed more
anteriorily than in Zémax; tail provided with a large slime
gland.

(a) Animal black, spotted with yellow, coarsely tuberculated ;
foot brown, transversely furrowed; sole light yellow divided into

0 vy, rufa, red, unicolor ; v. d7w2nea, coffee or rust coloured ; v. Draparnaude,
dark-red, foot-fringe yellowish or reddish; v. szcczzea, yellowish, unicolor ;
v. marginata, black, foot-fringe yellow, orange, or lead-coloured ; v. padlescens,
dirty white.

“ vy. grisea, pale grey, unicolor,

74. LAND AND FRESH-WATER SHELLS.

three bands by a median longitudinal band. Length 2 inches.
West Kerry, Ireland. 7 G. maculosus.

12. Amalia.—Shell oval or elliptical. Mantle granulated,
having the respiratory orifice on its posterior half; back keeled
from tail to mantle ; slime-gland absent.

(a) Animal varying in colour; mantle oblong, bilobed, rounded
behind, somewhat truncated anteriorily ; tentacles slate-coloured ;
slime colourless, glutinous. Shell oval, rugous, thick from
nucleus to centre. Length 2} inches. Gardens and hedgerows.
Local. A. gagates.”

(6) Animal varying in colour, truncated in front; mantle an
elongated oval, not bilobed ; head and tentacles dusky ; keel of a
lighter colour than the rest of the back ; slime colourless, glutinous.
Shell elliptical, somewhat concave, very thick. Length 23 inches.
Gardens and fields. Common. A. marginata.®

13. Limax.—Shell oval, oblong, quadrangular, or unguiform.
Mantle concentrically striated; respiratory orifice situated on
posterior half of mantle ; tail keeled, not the back ; slime gland
absent.

(a2) Animal fleshy, yellow, tessellated with black and white,
coarsely tuberculated; mantle broadly rounded behind; head,
neck, and tentacles slate colour; sole milk-white; slime yellow.
Shell oblong or quadrangular, thin, concave, margin mem-
branaceous. Length, 4 inches. Cellars and damp _places..
Common. L. flavus.“

(6) Animal varying in colour, generally creamy-white mottled
with dusky grey; mantle large, broadly rounded behind; foot
pale grey or cream colour; slime milk-white. Shell small, oval,
thin, margin membranaceous. Length } to 1} inches. Fields,
gardens, weods. Very common. Lo agresus=

2 vy, plumbens, lead-coloured ; v. vava, drab-coloured ; v. ol¢vacea, olive-
coloured.

8 vy, yustica, greyish, mantle reddish, with a longitudinal.black band on each
side; v. v2fzla, yellowish-red.

4! vy, virescens, greenish, spots indistinct; v. gvésea, ground-colour grey
instead of yellow, otherwise like the type ; v. suffwsa, grey, unicolor.

5 y, filans, greyish-white or ashy, mantle yellowish; v. zégva, jet black,
tentacles bluish or brownish-black, sole pale; v. sy/vatica, greyish, mottled ;

CLASSES, ORDERS, ETC. ai

(c) Animal dark brown, slender, very glossy; mantle very
tumid behind, pale yellowish-brown; sole ash-coloured; slime
almost colourless. Shell unguiform, convex above, flat beneath,
solid ; margin not membranaceous. Length +to #thsinch. Very
active. In damp situations. Moderately common. L. /evis.

(2) Body rounded, compressed towards the tail, greenish-white,
slender; head and tentacles black; mantle yellowish; slime
thick, orange-coloured. Shell oval, somewhat tuberculous, margin
broad, thin, membranaceous. Length #ths inch. Woods in Shet-
land and Northumberland. Local. L. tenellus,

(e) Body varies much in colour, banded; mantle pointed

behind ; dorsal tentacles short ; foot margin white; slime colour-
less. Shell oval, thin, nearly flat, margin broad and membranous.
Length 1} to 3 inches. In woods on trees, especially the beech
and walnut. Somewhat local. L. (Lehmannia) arborum.*®

(f) Body large ; tentacles long, vinous-coloured ; mantle buckler-
shaped, swollen, produced behind; slime whitish. Shell oblong,
solid, convex above, concave below, margin membranaceous.
Length, 3 to6 inches. Cellars, gardens,woods, fields, hedgerows.
Common. L. maximus.“

(g) Mantle unicolorous ; pulmonary orifice margined with the
same colour as the ground colour of the body but of a deeper tint ;
keel different in colour from the rest of the body; sole divided

v. punctata, greyish-white, minutely spotted with black ; v. ¢7s¢zs, brownish,
mantle with two lateral brown bands, and sometimes a third intermediate band ;
Vv. cimeracea, greyish-white, mantle ashy (type) ; v. sedmaculata, greyish-white,
streaked with seal-brown on the back which extends on to the posterior $rds.
of the mantle, the sides of the body, and anterior 4rd of the mantle are free
from streaks and spotted with black.

16 vy. maculata, cinereous with the markings reduced to small and sharply
defined black spots of a rounded or elongated form, and with a continuous
band on each side showing a tendency to break into spots; v. dczfvens,
brownish-grey, markings coalesced so as to produce the appearance of pale
spots on a dark grey ground, lateral bands on mantle ill-defined, no bands on
body, keel short, dorsal line partly obsolete.

% y. obscura, brown, unicolor ; v. maculata, ashy, mantle and back spotted
irregularly with black; v. -czwerea, ashy, spotless, mantle bluish-black; v.
Fohnstonz, ashy, mantle spotted with black, back marked with spots and two
bands of the same colour; v. 7wfescens, reddish, unicolor; v. fasctata, deep ash
colour with whitish bands, often five in number.

76 LAND AND FRESH-WATER SHELLS.

into three longitudinal bands, the middle one being white, the
two lateral ones dark. Length 3 to 6 inches. Gardens and
fields. Local. L. cinereo-niger.

Family W11.—Testacellide.

Shell small, auriculate, external, placed on the hinder portion
of the body, covering the mantle ; respiratory orifice on the right
side below the mantle.

4... Lestacella.

(2) Shell roundish-oval, depressed ; whorls one and a-half, the
nucleus making an angle of 45° to the vertical line ; spire short ;
suture deepish ; mouth roundish, dilated in front. Length j to 2ths .
inch, Animal with two longitudinal furrows on its back, which
commence from the shell and terminate near the head. Market
gardens and fields. Local. T. haliotidea.

(6) Shell resembling that of 7. Aaliotidea but smaller in propor-
tion to its length, flatter on its superior surface, comparatively
longer, more wedge-shaped, brownish, lines of growth finer and
less rugged, thinner, and the left side of the shell is more strongly
curved. Animal slightly more attenuated in front, and the longi-
tudinal furrows near the mantle are much closer together. ‘The
nucleus of the shell is placed at an angle of 60° or 70° to the
vertical line. The vas deferens enters the penis “terminally
in 7. scutulum and Maugei: laterally in T. haliotidea.” Gardens
and fields. Local. T. scutulum.

Fig 30.—A snail-slug (Testacedlla).

(c) Shell resembling that of 7. Aaliotidea, but larger and more
cylindrical. Body dark brown. Gardens and fields round
Bristol. T. Mauget.

Family. 1V.—Helicide.

Shell spiral. Body distinct from the foot, tentacles four, re-

CLASSES, ORDERS, ETC. Vu:

tractile, cylindrical, the upper pair being the longest and bearing
the eyes at their apices.

15. Succinea.—Shell oval or oblong, thin, transparent ; spire
short ; mouth large and obliquely oval; non-operculated. Animal
not capable of entirely entering its shell.

(a) Shell, ovate, oblong, smooth, glossy, amber-coloured, trans-

Fig 31.—Szuccinea putris.

parent ; whorls three to four, ventricose, the body-whorl occupy-
ing 4ths the length of the shell ; mouth ovate, two-thirds the length
of the shell. Length 3 to #ths inch. On the banks of ditches and
streams on flags and willows. Moderately common.
S. putris.8
(4) Shell oblong, suboval, thin, greenish-yellow, transparent ;
spire very short ; mouth ovate. Length 2ths inch. Marshes and
ditch-banks. Moderately rare.
; S. virescens, (=Succinea putris var. vitrea.)
(c) Shell amber-coloured, semi-transparent ; compared with that
of .S. putris it is smaller, more slender, with a longer and more
pointed spire; the suture near the mouth is also much deeper.
Length Linch. Marshes and ditch-banks. Moderately common.
S. elegans.®®
(d) Shell oval, elongated, pale yellow or reddish, transparent ;
whorls three, twisted, the body-whorl occupying near the whole
of the shell ; spire short, with the apex tuberculous ; suture oblique,
well defined but not deep; mouth an elongated oval, about §rds

48 y. subglobosa, shorter, broader, smaller, more solid; v. solédula, reddish-
yellow, much thicker; v. /erussina, deep reddish-fawn coloured, small,
slightly elongated.

vy, albida, white; v. minor, thinner, reddish-brown, spire shorter, aperture
more expanded ; v. ochracea, thicker, smaller, spire longer, aperture smaller.

78 LAND AND FRESH-WATER SHELLS.

~

and ditch-banks. Moderately common. S. Pfeifer

(ce) Shell small, oval, somewhat like that of L. ¢runcatula, light
horn-coloured ; whorls four, convex; suture deepish; spire pro-
duced, with a blunt apex; mouth oval, about the same length as
the spire. Distinguished from L. /runcatula by having no reflected
lip on the columella. Length } inch. Edges of ditches near
the coast, and on sanddunes near the sea. Rare. S. oblonga.

16. Vitrina.—Shell subglobular, thin, flattened ; mouth large
and semilunar ; umbilicus wanting.

(2) Shell depressed, thin, glossy, glassy-green ; whorls three to
four, the body-whorl being very large ; spire very short; mouth
large, somewhat oval. Height 34th inch, Among moss and dead
leaves in woods and hedge-banks. Moderately common.

V. pellucida.”

7. Hyalina. (Zonites).—Shell orbicular, depressed, umbil-
cated ; mouth obliquely crescent-shaped.

(a) Shell slightly convex above, glossy, striae demi-effaced,
reddish above, whitish below, especially round the umbilicus ;
whorls six to seven, the last whorl slightly dilated towards the
aperture ; umbilicus largish ; mouth oval, very oblique. Diameter
1 to #ths inch. Very local. Found only, as yet, at Guernsey, Tor-
quay, Falmouth, Bristol and Isleworth, London. &@. Draparnald:.

(2) Shell dirty yellow or pale horn-coloured, glossy, under
surface white, especially about the umbilicus ; whorls five to six ;
spire very flat; umbilicus rather open; mouth crescent-shaped.
Diameter 4 inch. Under stones in fields and woods, about walls
in gardens. Common. FT, cellaria.*?

of the total height of the shell. Length }2ths inch. Marshes

°° y, ventricosa, spire more elevated, body whorl convex, aperture large, less
elevated, a little more than half the total height of the shell; v. propingua,
shell elongated, ventricose, body-whorl very large, spire short, aperture large,
oval; v. edata, shell very slender, spire long and very tortuous, body-whorl
very contracted at its origin, aperture oval and scarcely one half of ‘the total
height of the shell ; v. vzvescens, greenish, spire elongated, suture deep.

1 y, Dillwynii, nearly globular, last whorl very convex, spire more promi-
nent; v. depressiuscula, rather oval, flatter on both sides, spire scarcely
raised. .

2 vy, complanata, smaller, spire flatter ; v. compacta, body-whorl less swollen.
not so white beneath, more compact and convex.

CLASSES, ORDERS, ETC. 79

(c) Animal emitting an alliaceous smell. Shell amber or horn-
coloured, thin, upper surface smooth and darker than the lower
surface, which is not so white as in the other species ; whorls five,
the last not so large in proportion as in /. cellaria ; spire more
raised than in ZZ. cellaria,; umbilicus moderately large, exposing
the second whorl; mouth narrow, crescent-shaped. Diameter }
inch. Walls, gardens, woods. Slightly more local than ZH. ce/laria.

f1. alliaria.®®

(Z) Shell convex above, less convex below and only very
slightly marked with white, darkish horn-coloured ; whorls five to
five and a half, the body-whorl occupying about one-half of the
shell ; spire slightly produced, umbilicus narrow, deep, not dis-
closing the penultimate whorl, mouth forming three-fourths of a
circle. Diameter 2ths inch. Woods and fields. Local.

fT, glabra.

(ce) Shell subpellucid, dull waxy-coloured above, paler below,
clouded with opaque white round the umbilicus ; whorls four to
five, marked with irregular placed strize, which are interrupted by
the sutures and not continued from whorl to whorl ; spire slightly
produced; mouth semilunar; umbilicus very large. Diameter
3ths to 3,ths inch. Under stones and amongst moss on hedge-
rows and old walls. Common. Ff. nitidula.**

(f) Shell whitish or light horn-coloured, glossy, thin, with
numerous transverse circular striz; whorls four, the body-whorl
occupying nearly one-half of the shell; spire not much raised ;
suture deep, narrow; mouth roundish, oblique; umbilicus narrow,
deep, disclosing all the internal spire. Diameter ;'>th to }th inch.
Under stones and decayed leaves in woods and fields. Somewhat
local. . fl. pura.”?

(g) Somewhat like 4 pura but more glossy, regularly striated,
horn-colour; whorls four to four and a-half with the strize extend-
ing from whorl to whorl and not interrupted by the sutures as in
HZ, nitidula ; spire much depressed ; mouth semilunar; diameter

33 y. viridula, greenish-white.

5ty. Helmiz, pearl-white; v. s/¢ens, much smaller, lighter coloured, las
whorl expanded. ,
' % vy. margaritacea, pearl white, nearly transparent.

80. LAND AND FRESH-WATER SHELLS.

41ths to 1th inch; umbilicus moderately deep. Among moss and
wet grass. Generally distributed, but not common.
FI. radiatula,®
(2) Shell subglobular, chocolate-brown, no white on under side,
solid, glossy, semi-transparent ; whorls five, body-whorl occupying
one-half of the shell ; spire produced, with the apex blunt; mouth
roundish, forming three-fourths of a circle; umbilicus narrow,
deep. Diameter inch. Marshes and banks of ditches.
Hf, nitida.*!
_ (¢) Shell suborbicular, not very glossy, darkish horn-coloured,
coarsely striated; whorls five and a-half; spire slightly produced ;
mouth nearly circular; umbilicus large, disclosing all the internal
spire. Among moss and dead leaves in woods. Local.
fT. excavata.
(7) Shell flat above, convex below, vitreous, smooth, glossy,
transparent ; whorls four and a-half to five, the body-whorl being
scarcely smaller than the preceding whorl; mouth lunate ;
umbilicus very small. Diameter ;ths inch. Among moss and
decaying leaves in woods and hedgerows. Common.
LZ. crystallina,®®
(4) Shell conical, dark horn-coloured, smooth, glossy, semi-
transparent; whorls five and a-half to six; periphery bluntly
keeled; spire produced; mouth semilunar, narrow; umbilicus
shallow, indistinct. Diameter th inch. Under stones and
among decaying leaves in woods and hedgerows. Moderately
common. HT, fulva.
18. Helix.—Shell globular, turreted, convex or flattened ;
mouth more or less circular or oval; outer lip generally thick and
possessing an internal rib, sometimes reflected and provided with
tubercles or teeth ; umbilicus sometimes absent but usually distinct.
(2) Shell conoid, globose, thin, horn-colour; epidermis raised
into numerous close-set plaits in line of growth; whorls six,
convex; spire blunt, slightly depressed ; mouth crescent-shaped ;

56 vy, virtdescentt-alba, greenish-white.

57 vy, albinos, whitish.

8 vy, complanata, flatter on both sides, last whorl proportionably larger.

_ 8% vy, Alderi, smaller, darker brown; v. MJortoni, depressed above, less
flattened below, peripheral keel sharper.

CLASSES, ORDERS, ETC. SI

umbilicus small, very deep, distinct. Height *~,thsinch. Among
holly leaves in woods and groves. Local. FT. lamellata.
(5) Shell conical, turreted, globose, brownish horn-colour ;
epidermis raised into numerous plaits, which, in the middle of each
whorl, become produced into points; whorls four to four and a-
half; aperture nearly crescent-shaped ; umbilicus small. Height
ths inch. Among moss and dead leaves in woods and hedge-
rows. Moderately common. fT. aculeata.©
(c) Shell very large, globose, coarsely striated, strong, whitish-
yellow banded with brown; whorls four to five, the body-whorl
very large ; spire short, blunt ; mouth roundish ; inner lip reflected ;
umbilicus narrow. Height.1 $4ths inch. Woods and hedgerows
in chalky districts. Local. FT. pomatia.®!
(d@) Shell conoid, globose, wrinkled, yellowish-brown with
interrupted dark bands, solid ; whorls four to five and a-half,

Fig. 32.—Helix aspersa.

convex, the body-whorl being very large in proportion ; spire short,

blunt; aperture oval; umbilicus none. Height 1 {ths inch.

Gardens, fields, hedgerows. Very common. HZ. aspersa.”
(e) Shell subglobose, glossy, banded or unicolor ; whorls five

to five and a-half, convex; spire short, blunt at apex; mouth
6 vy. albida, whitish.

v. albida, whitish, unicolor.

v. exalbida, yellowish or whitish, unicolor; v. gvisea, tawny or greyish,

with extremely pale bands; v. /fammea, reddish with longitudinal flame-shaped

markings ; v. ¢enzzor, smaller, very thin, transparent, reddish, unicolor ; v.

albofasciata, reddish-brown, with a single white band ; v. g/ovesa, larger, nearly

globular ; v. mznor, shell smaller ; v. covozdea, thinner, smaller, conical, mouth
small.

61

62

6

82 LAND AND FRESH-WATER SHELLS.

semilunar ; inner lip thin, reddish-brown or chocolate-coloured ;
outer lip strong, reddish-brown ; umbilicus covered by the inner
lip. Height 2ths inch. Among nettles in woods and hedge-
banks. Common. fT, nemoralis.®
(/) Shell resembling that of /Z. xemoralis but smaller, more
globular, rather thinner, and possessing a white or rose-coloured
peristome. Same localities as last species. Common.
FT. hortensis.™

(g¢) Shell globose, brown marked with yellowish spots, and a
single black band round the periphery of each whorl; whorls
- five to six, convex; spire conoid, short, blunt; mouth rounded,
lunate ; peristome white; umbilicus distinct. Height }&ths inch.
Among the reeds and willows of ditch sides and river banks ;
in woods and hedgerows. Rather local.

FT, arbustorum.©

(i) Shell somewhat depressed, thin, yellowish-horn coloured
or creamy-white tinged with rose near the mouth, faintly banded
with white on the periphery; whorls six to seven, convex, the
body-whorl occupying one-half of the shell; spire short, blunt ;
mouth lunate, with a white or rose-coloured rib ; umbilicus narrow,
deep. Height $4ths inch. On nettles, and in marshy places, in
some of the southern and northern counties of England. Local.

fT, cantiana,®

& vy, castanea, brown; v. carnea, flesh-coloured; v. “bellula, yellow; v.
rubella, pink; v. albescens, whitish; v. hyalozonata, with transparent bands ;
v. major, very large; v. albolabiata, with mouth and lip white ; v. d¢marginata,
peristome brown exteriorly, white interiorly ; v. conozdea, spire an elevated
cone.

6 vy, albina, white or whitish ; v. fal/éda, very pale yellow; v. zucarnata,
rose-coloured; v. olivacea, deep olive-brown ; v. /utea, yellow; v. mznor,
dwarfed ; v. Zilactna, bluish-violet ; v. avezzcofa, with transparent, colourless
bands ; v, fuscolabiata, peristome and rib dark ; v. voseo-labiata rib pink or
rose-coloured.

% y, flavescens, yellowish, unicolor; v. major, larger, spire more
depressed; v. conoidea, conical, large, with transverse, somewhat confluent
pale yellow markings ; v. a/festris, half the usual size, more depressed ; v.
fusca, brown, nearly unicolor, thin, subtransparent.

6 vy, albida, white; v. pyramidata, smaller, spire more raised, pyramidal ;
v. Galloprovincialis, last whorl less depressed, lighter in colour, umbilicus more
narrow, peristome reddish exteriorly, white interiorly.

CLASSES, ORDERS, ETC. 83

(?) Shell depressed, subconic, not so glossy as WH. cantiana,
whitish-horn colour, with a white spiral band just above the
periphery ; whorls six to seven, faintly keeled, the body whorl
very large; spire acute, more depressed than in A. cantiana ;
suture rather deep ; mouth crescent-shaped with a white internal
rib; umbilicus very small. Height ,*,ths inch. Among grass
on the Kent and Sussex downs, near the sea. Local.

ff. Cartusiana.™

(7) Shell depressed, subconic, dull brown, more or less reddish,
subcarinated, generally with a white band at the periphery; spire
short, blunt; mouth semt-elliptical with a white internal rib;
umbilicus narrow, deep. Height {4ths inch; diameter 2ths to
34ths inch. Under stones in hedge-banks. Common.

FT, rufescens.®8

(2) Shell suborbiculate, depressed, thin, yellowish-brown, epi-
dermis covered with fine white recurved hairs arranged in spiral
lines ; whorls six to seven, convex, the body-whorls occupying
one-third of the shell; spire blunt, slightly raised; aperture
crescent-shaped ; umbilicus narrow, deep. Height 1th inch.
Among moss, and under stones, etc., in shady places. Common.

HF. hispida.

(/) Like ZH. hispida but larger, less globose, hairs more liable
to fall off; umbilicus wider. Height 7 inch. In similar situations
to the last. Common. fH. concinna.”®

(m) Shell subglobular, thin, dark brown or pale grey, marked
with a few faintly-marked brown streaks, epidermis covered with
white hairs ; whorls six, convex, the body-whorl occupying nearly

7” v. leucoloma, small, peristome and rib white ; 77//abris, smaller, inside rib
reddish.

* v. alba, entirely white ; v. vzdens, more or less reddish ; v. #zé20r, smaller,
spire more raised.

® v. fusca, light brown; v. subrufa, reddish, glabrous, thicker; v. zana
smaller, labial rib strong, spire depressed ; v. s«g/obosa, more globular, thinner,
horn-coloured or white, umbilicus very small ; v. covzca, smaller, spire more
raised ; v. a/bzda, thin, white or colourless.

* v. minor, smaller, spire more raised ; v. alba, white. (This species is
probably a variety of Z/, Azsfzda, as structurally it is not distinct.)

84 LAND AND FRESH-WATER SHELLS.

one-half of the shell; spire blunt, much raised ; mouth crescent
shaped, with a white internal rib; umbilicus deep, very minute.
Height ..ths inch. In woods and damp places. Somewhat
local. FT, sericea.”
(x) Shell subglobose, depressed, thin, greenish-horn coloured,
transparent, scantily covered with short hairs; whorls four and
a-half, convex, the body-whorl occupying two-thirds of the shell ;
spire blunt, not much raised; suture deep; mouth somewhat

Fig. 33.—(a) Helix sericea and (6) Helix hispida.

circular, not provided with a rib; umbilicus minute. Height
4th inch. Among nettles. Very local. FT, relevata.

(0) Shell subconical, depressed, faintly keeled, horn-coloured,
smooth, strongly corrugated in line of growth, thin, transparent ;
whorls five and a-half, convex ; spire blunt, somewhat produced ;
suture shallow; mouth crescent-shaped; umbilicus very small.
Height #th inch. Among decayed leaves in woods, especially
those of the sycamore and alder. More or less local.

LT, fusca.

(f) Shell subglobular, yellowish-white, marked with chocolate-
brown bands and dots, giving the shell a mottled look, solid ;
whorls five to five and a-half, the body-whorl occupying two-
thirds of the shell; spire blunt; mouth rose-coloured, crescent-
shaped; umbilicus small. Height 34ths inch. Sandhills near
the sea. Local. Hf, Pisana."?

(7) Shell conical, somewhat globular, cream-coloured, with a
single dark brown band on the periphery of the body-whorl, and

” y, cornea, horn-coloured, thin, labial rib perceptible on the outside,

” vy. alba, white or pale yellow,

CLASSES, ORDERS, ETC. 85

several bands below it; whorls six, convex; mouth rounded,
purplish-brown interiorly; umbilicus narrow, deep. Height
42ths inch. Downs and sandhills near the coast. Local.
FH. virgata.”
(r) Shell subconical, depressed, whitish or dull yellowish-white,
banded with brown, solid ; whorls six, periphery bluntly keeled ;
spire slightly raised, with the apex tipped with brown ; mouth
roundish, with a strong white internal rib; umbilicus large.
Height ,.ths inch. Under stones and among grass on sandy
soils. Somewhat local. FT. caperata.4

(s) Shell circular, depressed, greyish or whitish, banded with
chestnut-brown; whorls six, spire slightly raised with a brown
apex; periphery not keeled; mouth almost circular; umbilicus
large and open, exposing three or four whorls. Height ths
inch. Heaths and downs near the sea. Local.

EZ. ericetorum.”

(¢) Shell depressed, circular, yellowish or reddish, regularly
marked with rufous brown; whorls six to seven, outer margin
strongly keeled ; spire slightly produced ; mouth crescent-shaped ;
umbilicus large and deepish. Height #,ths inch. Under stones
and among decaying leaves. Common. HT. rotundata."®

(w) Shell sub-conical, depressed below, transverse strize oblique
and strong, blackish-brown; whorls five to six, with the spire
somewhat produced ; mouth nearly circular, gibbous ; umbilicus

*3 y. subglobosa, smaller, with a double band above the periphery, umbilicus
wider; v. sabaperta, whitish, spire more depressed, umbilicus wider; v.
leucozona, violet or reddish-brown, whitish band at periphery ; v. sabmaritima,
smaller, darker, slightly pyramidal ; v. cavinata, strongly keeled, yellowish-
white, compressed above.

74 y, ornata, smaller, whitish, with one brown band above, and two to six
below ; v. major, larger ; v. Gigaxid, smaller, more depressed, reddish, spotted,
marked by two bands below ; v. swdscalaris, conical, whorls more convex ; V.
alba, pure white, unicolor.

% vy, zustabilis, smaller, darker, spire more raised, umbilicus narrower,
sometimes streaked or spotted ; v. a/éa, white, unicolor; v. /zfescens, dirty-
yellowish, unicolor ; v. 72707, smaller.

78 y, alba, white unicolor; v. Zwrtoniz, almost flat above; v. mznor
smaller ; v. Ayvamidalis, subconical, spire more raised.

86 LAND AND FRESH-WATER SHELLS.

large, deep. Height “ths inch. On old walls and castle-ruins.
Somewhat local. Al. rupestris.“
(v) Shell very minute, depressed, nearly circular, yellowish
horn-colour ; whorls four, with the spire somewhat produced ;
mouth semilunar; umbilicus large, deep. Height ;',th inch.
Among dead leaves, and under stones. Moderately common.
LF. pygmeea.
(w) Shell nearly circular, sub-depressed, milk-white ; whorls
three and a-half, the body-whorl exceeding in size the rest of the
shell ; spire slightly produced ; mouth circular, thickened and
reflected so as to form a double peristome ; umbilicus large,
deep. Height ths inch. Among stones, moss, and grass.
Somewhat local. FT. pulchella.
(x) Shell sharply keeled at the periphery, circular, depressed,
greyish or horn-colour, streaked regularly with rufous brown ;
whorls five, with the spire very slightly produced; mouth oval,
surrounded by a thick white reflected rim, somewhat angulated
above and below; umbilicus large, deep. Height ,4ths inch. In
hedgerows and woods in calcareous districts. Local.
FT. lapicida.™
(y) Shell sub-discoidal, depressed, solid, dull rufous-brown
hispid ; whorls six and a-half ; spire sunk below the level of the
body-whorl ; mouth triangular, marked with three protuberances,
and with a pinkish-white, reflected peristome ; umbilicus large,
deep. Height .°ths inch. Among the moss near the roots of
shady trees at Ditcham Wood, Hants. Rare. HT. obvoluta.
(z) Shell turreted, conical, yellowish-white streaked with
brown, and with generally a reddish-brown or blackish band
below the periphery ; whorls eight to nine; spire tapering, blunt ;
mouth oval ; umbilicus narrow, rather shallow. Height 2ths inch.
On cliffs and downs near the coast.
fT. (Cochlicella) acuta (= Bulimus acutus).*°

™ vy. viridescenti-alba, greenish-white.

8 v. costata, not so glossy, reddish with numerous transverse, membranous
ribs as well as intermediate striz.

v. albina, whitish, unicolor ; v. mzor, dwarfed.

* vy. inflata, slightly ventricose; v. s¢¢gata with broad, whitish ribs

CLASSES, ORDERS, ETC. 87

rg. Bulimus.—Shell oval or oblong-ovate ; spire blunt, but
much more prominent than in /e//x_; mouth an elongated oval ;
umbilicus very small. Tentacles shorter than in He//x.

(a) Shell oblong, conical, light brown or dark brown; whorls
six and a-half to seven and a-half, compressed, the body-whorl
occupying slightly less than half the shell; spire tapering, blunt ;
mouth oval, pinkish or brownish inside, and with a thick peris-
tome which is reflected over the umbilicus; umbilicus narrow,
deep. Height ths inch. Among fallen beech leaves in the
southern and western counties. B. montanus.

(0) Shell oblong, oval, brown, more glossy than 2. montanus ;
whorls six and a-half, rounded; spire elongated, blunt; mouth
oval, with a white, reflected peristome ; umbilicus narrow, but not
deep. Length 35 lines. Among moss and stones in woods and
hedge-banks. Moderately common. B. obscurus.*}

20. Pupa.—Shell cylindrical or oblong, with many narrow
whorls ; mouth oval or lunate, generally toothed within ; _peris-
tome incomplete, thickened, reflected; umbilicus very minute.

(a) Shell sub-cylindrical, solid, rufous-brown, conical ; whorls
eight to nine, spire produced ; mouth semi-oblong, with eight or
nine denticles ; umbilicus small, oblique. Height .8ths inch.
On rocks and at roots of trees in calcareous districts. Local.

P, secale. 8?

(6) Shell ovate, conical, sub-cylindrical, light brown or yellow-
ish horn-colour ; whorls six to six and a-half; mouth sub-semi-
circular, with seven or eight reddish plications ; umbilicus oblique,
distinct, narrow. Height ;4ths inch. Among moss and dead
leaves, under stones. Local. P. ringens.

(c) Shell oblong, sub-cylindrical, glossy, yellowish-brown or
dark horn-colour; whorls six to seven, rounded; mouth semi-
oval, with a single denticle at the angle formed by the junction
of the outer lip, which is broad and much reflected ; umbilicus

alternating with brownish-grey streaks ; v. d¢zowa, greyish or whitish, strize
obliterated, with two dark bands on the body-whorl.

8! vy. albinos, whitish, unicolor,

* vy. edentula, peristome without teeth; v. alba, white ; v. Botleaustana,
larger denticle entirely double, with a supernumerary projecting denticle at the
angle of the columellar border.

88 LAND AND FRESH-WATER SHELLS.

small, narrow. Height ;4ths inch. Among moss and dead
leaves ; under stones and the bark of old trees. Common.
: P. umbilicata.*®?

(¢) Shell cylindrical, ovate, finely striated, dull brownish horn-
colour ; whorls six to seven, convex; mouth sub-semicircular,
provided with a small denticle placed in the middle of-the base
of the last whorl, and a strong, white, external rib behind the
outer lip; umbilicus narrow. Height =jths inch. In moss and .
under stones on sandy soils. Somewhat local.

P. marginata.*4

21. Vertigo.—Shell dextral or sinistral, sub-cylindrical with
closely pressed, gradually-enlarging whorls; mouth more or less
angular, generally toothed internally; umbilicus minute. Re-
sembles Ppa, but differs in having the ventral tentacles wanting,
and in having the peristome thinner.

(a) Shell dextral, oval, shining, chestnut-brown ; whorls four
and a-half, the body-whorl comprising about one-half of the
shell; mouth subcordate, with from six to eight reddish-brown
denticles; umbilicus narrow, distinct. Height ;/;th inch. Under
stones in marshy places. Moderately common.

V. antivertigo.®

(0) Shell dextral, oval, ventricose, light yellowish horn-colour ;
whorls four and a-half, globose, the body-whorl comprising more
than half of the shell ; suture exceedingly deep ; mouth semi-oval
with four or five denticles; umbilicus open. Height ;,th’inch.
Rare. V. Lilljeborgi.®®

(c) Shell resembling /. Lz2/jeborg?, but more swollen and barrel-
shaped, and with the labial rib much stouter. Rare.

V. Moulinsiana.

(d) Shell dextral, ovate, somewhat cylindrical, reddish-brown ;
whorls four and a-half to five, the body-whorl occupying about
one-half of the shell, convex; mouth semi-oval with four or five

8 vy. edentula, without denticles; vy. a/bzza, entirely white.

v. albina, whitish, * unicolor; v. dégranata, with a dentiform palatal
callosity.

® v. sexdentata, with six denticles ; v. octodentata, with eight denticles.
v. didentata, labial or palatal teeth wanting.

81

86

CLASSES, ORDERS, ETC. 89

teeth ; umbilicus rather deep, narrow. Height th inch.
Under stones and logs of wood. Moderately common.
V. pygmea,*
(e) Shell somewhat like that of VY. pygmea but differing in
being more cylindrical, lighter in colour, more strongly striated,
and in the absence of any rib. Among grass and dead leaves in
the northern counties. Local. _V. alpestris.
(7) Shell dextral, shortly ovate, glossy, thin, light yellowish-horn
colour; whorls four and a-half, very ventricose, with the spire
very short and abrupt; suture very deep; mouth sub-pyriform
with six teeth; umbilicus small, contracted by a basal ridge.
Height #.ths inch. Among grass, dead leaves, and under stones.
Moderately common. V. substriata.
(¢) Shell dextral, ovate, cylindrical, pale brownish-horn
coloured ; whorls five to six and a-half; spire conical, blunt;
mouth subsemi-oval, without teeth ; umbilicus narrow, rather deep.
Height +th inch. Among moss and dead leaves, under stones.
Local. V.. edentula,
(A) Shell dextral, cylindrical, glossy, horn-colour, narrower and
smaller than V. edentula ; whorls five and a-half, increasing in size
to the third, and then becoming of the same breadth; suture
deepish ; mouth oblong, without teeth ; umbilicus narrow, oblique.
Height ths inch. Under stones on hillsides. Very local.
V. minutissima.
(2) Shell sinistral, somewhat fusiform, glossy, thin, pale yellowish-
horn colour; whorls four and a-half to five, ventricose; suture
deep ; mouth subquadrate, with six or seven denticles ; umbilicus
small, contracted by a basal ridge. Height ~;ths inch. Among
moss and decayed leaves, under stones. Very local. V. pusilla.
- (y) Shell sinistral, fusiform, pale horn-colour, glossy, smaller
and narrower than V. pusilla ; whorls four and a-half, the pen-
ultimate whorl being the largest; suture deepish ; mouth trian-
gularly subcordate, with from four to five denticles ; umbilicus
small, contracted by a basal ridge. Height = ths inch. At the
roots of grass. Extremely local. V. angustior.
22. Balia.—Shell sinistral, elongated, thin; mouth ovate,

8? y. pallida, thinner, lighter in colour.

gO LAND AND FRESH-WATER SHELLS.

sometimes with a denticle at the base of the penultimate whorl ;
peristome thin, umbilicus narrow.

(2) Shell fusiform, turreted, glossy, yellowish horn-colour
streaked with white; whorls seven to eight; suture deepish ;
mouth rounded, pear-shaped, with sometimes a denticle near the
middle of the base of the penultimate whorl; umbilicus small.
Height “ths inch. Under the bark of old trees. Local.

B, perversa.®

23. Clausilia.—Shell sinistral, fusiform; mouth pyriform or
elliptical, toothed, furnished with a clausilium; umbilicus very
small.

(a) Shell cylindrical, glossy, chocolate-brown or horn-coloured,
marked with whitish streaks ; whorls ten to thirteen ; mouth pyri-
form, furnished with two plications on the base of the penultimate
whorl with one to three smaller plaits between them, and with
two plications on the columella; umbilicus narrow; clausilium
oblong. Height 2ths inch. Under stones, logs of wood, and
among grass on hedge-banks, on trunks of beech, willow, and ash
trees. Common. C. rugosa.®9

(5) Shell fusiform, reddish or yellowish-brown ; whorls nine to
ten, swollen ; mouth rounded, pyriform, with plaits as in C. rugosa,
but the lower one on the base of the penultimate whorl is less
prominent and sometimes cruciate ; umbilicus indistinct ; clausilium
oblong. Length $3ths inch. Among dead leaves and under
the bark of tress. Rare. C. Rolphii.

(c) Shell fusiform, yellowish-brown, streaked with white ; whorls
twelve to thirteen, compressed ; mouth pear-shaped, canaliculated,
with the same plaits as in the two foregoing species, except that
the teeth between the plications on the base of the penultimate
whorl are not represented ; umbilicus rather broad, basal crest
prominent, clausilium oval. Length }iths inch. On the bark
of willow trees. Very local. C. biplicata.

8 vy, wviredula, greenish-white, transparent.

89 y. dubia, larger, more ventricose; v. gracilior, longer, more slender; v.
tumidula, smaller, shorter, more ventricose; v. Zveretti, shorter, whorls
fewer ; v. Schlechtiz, like v. dubia but larger, elongated, smoother, and more
transparent, pale brown. (Possibly v. dudéa is a distinct and separate
species.)

CLASSES, ORDERS, ETC. QI

(7) Shell fusiform, large, yellowish-brown, glossy ; whorls
twelve; mouth oval, pear-shaped, with two very strong plaits on
the base of the penultimate whorl, and two or three labial plaits
which are distinctly visible through the shell; umbilicus small ;
basal crest slight ; clausilium with a notch on the margin near its

Fig. 34.—Clausilia biplicata.

base. Height 3iths inch. On beech and ash trees. Moderately
distributed; but local. C. laminata.®

23. Cochlicopa.—Shell oblong or oblong oval, very glossy,
transparent ; mouth pear-shaped; outer lip thickened, not re-
flected.

(2) Shell fusiform, pale yellowish-brown, glossy; whorls
seven ; spire produced, blunt; suture shallow; mouth pear-
shaped, with three or more plications. Length ?;ths inch.
Among moss and decaying leaves. Moderately common, but
local. C. tridens.|

(2) Shell oblong, not so ventricose as C. ¢ridens, yellowish-brown
or greenish-white, glossy ; whorls five to five and a-half; suture
rather deep; mouth oval, without plaits. Height ,%ths inch.
Among moss and decaying leaves. Common. C. lubrica.”

° vy. albinos, entirely white; v. Ze//ucida, thinner, more transparent, very
glossy.

1 vy, crystallina, greenish-white, transparent, glossy.

® vy. hyalina, greenish-white ; v. fzsca, more or less a deep brown colour ;
v. Zubricoides, smaller, more slender ; v. vzrédula, shaped like v. Zubricotdes, but
greenish-white ; v. ovata, smaller, oval, spire shorter.

Q2 LAND AND FRESH-WATER SHELLS.

25. Achatina.—Shell cylindrical, smooth, thin, glossy ; mouth
oval, with a notch at its base; outer lip thin and not reflected;
umbilicus absent.

(a) Shell fusiform, white ; whorls five and a-half to six; spire
attenuated ; suture deep ; mouth lanceolate, sharply angled above,
notched deeply at its base. Length j4ths inch. Subterranean ;
specimens are often found in river ejectamenta after floods.

local; A. acicula.

Family V.—Carychiide.

Shell spiral, oblong ; mouth oval, denticulated ; umbilicus very
small. Eyes situated at the posterior base of the dorsal tentacles ;
lower tentacles rudimentary.

26. Carychium.

(a) Shell white, fusiform, oblong; whorls five to five and a-half,
the body-whorl comprising nearly one-half of the shell; apex
acute; mouth ear-shaped with three denticles; umbilical chink
oblique. Height 3th inch. Under stones, in decaying leaves,
and at the roots of grass. Moderately common. C. minimum.

Family Vi.—Cyclostomatidee.

Shell cylindrical or conical, operculated ; mouth round or oval ;
operculum shelly or horny.

27. Cyclostoma.—Shell conical; operculum shelly.

(a) Shell greyish or yellowish-brown streaked and blotched
with purplish-brown, coarsely striated; whorls four and a-half,
tumid; suture deep; mouth subrotund; umbilicus narrow.
Length 34ths inch. In hedgerows and on hillsides in calcareous
districts. Moderately common. C. elegans.*8

28, Acme.—Shell cylindrical; operculum horny.

3 y, ochroleuca, yellowish, unicolor, bandless; v. pallida, very pale

yellowish, with some spots and demi-effaced bands; v. albescens, whitish,
unicolor.

CLASSES, ORDERS, ETC. 93

(z) Shell light brown, attenuated, glossy, strongly striated in
line of growth; whorls six to seven ; suture well defined; mouth
pyriform, contracted above; umbilicus minute. Height = ths
inch. Under stones and among decaying leaves. Moderately
common, but local. A. lineata.

* vy, alba, white or colourless, transparent ; m. sz77strorsum, spire sinistral.

CHAPTER We.

CENSUS OF THE AUTHENTICATED DISTRIBUTION OF BRITISH
LAND AND FRESH-WATER MOLLUSCA.

By JOHN (W. TAYLOR) I¢bS;
AND W. DENISON: ROEBUCK, F.L:S.

WITH the view of facilitating the labours of the numerous con-
chologists and others who are throughout the United Kingdom
assisting us in working out the detailed distribution of the British
land and fresh-water mollusca, and also of those who may here-
after be disposed to assist us by submitting specimens for °
authentication and record, the following “ census ” has been framed.
It is strictly limited to “authenticated ”’ records, that is, to such
as are verified by specimens which have passed under the
examination of the Conchological Society’s referees. This pro-
cess secures uniformity of value in the results.

The numbers are those of counties and vice-counties, a key
to which will be found at the end of the chapter. It will be
seen that the Channel Islands are denoted by the cypher “ 0” and
that they precede district No. 1. The total number of counties
and vice-counties for which we have seen specimens Is given
under each species.

For the present the disnabution of the varieties cannot be
given, and some of the doubtful species—such, for example, as the
mythical Avion flavus—are also omitted.

Conchologists—and naturalists generally—are requested to aid
in filling up-the gaps in the records by sending us specimens for
authentication and study. They will not fail to note how very
imperfectly the mollusca of Scotland and Ireland are recorded.

CENSUS. 95

Testacella maugei Fér. Nine counties.
Png 5. of OGg 22 34., Wales 41 45. .Irels r45.. No
records for Eng, N., or Scotland.
T. haliotidea F.-Big. Eight counties.
Paces se 3 '3-04, 22-23 25) 34. Eng. N: i612 Ire.
146. No records for Wales or Scotland.
T. scutulum Sow. Thirteen counties.
Bug. SS: fo 13.15—17 20-25 27-28 37. . Eng. N.
55-50 58 61 66. . Scot. 86. -No records for Wales or
Ireland.
Arion ater L. Ninety-one counties.
Eng. S. i1—13 16—21 24—26 28—30 32—40.
Wales, 41-42 45—s2. Eng. N. s4—67 69—71. Scot.
Pei oe o2- 82. 80-87-1900..92) O6,-9o—I0l 103 1O7-—100:
Trel. r114—116 118 124 136 138 145-146.
Arion subfuscus Drap. Forty-four counties.
Bags 5S) F.2 5), 9-84.21 34, 30-40: . Wales 40.45
“a7 490. Eng. N.. 54 56—59:-62 64—67 60... Scotp 77 79
Pama d2. OS. TOO-lOL (tO5), 10%, rel. rig 16y req ue6
B20: 130-145.
A. hortensis Fér. Seventy-five counties.
Eng. S. 1 4—6 8 10—13 I5—17 20—22 24 30 32—
4o. Wales 41 45—52. Eng. N. 53—59 61—66 60.
Scot. 75—77 79 81—86 88 90 95 98—I00 105 107
opt 6G. lrel. ERA) T24)-127 | T4A5 140.
A. bourguignati Mab. Sixty-eight counties.
Eng. 5. 1-2 4 9 II—13 16-17 21 25 28 30 34—40.
Wales 41 47—49. Eng. N. 53—58 60—67 69. Scot. 75—
85 87-88 90 92 96 98—I00 103 107-108 110. Irel. 114
124 127 145 147-148.
Geomalacus maculosus Allm. One county.
Is found only in county Kerry.
Amalia gagates Dp. Twenty-four counties.
Eng. S. I 3 5 9—II 14-15 21 35-36 39-40. Wales
Agen Ee IN 5A) 56) ..02- 66; Wins Scot.) 83::Tdo. oleel:
Tis. T24 136.
Amalia marginata Mill. Thirty-six counties.
Eng. S. 1 3—6 9—I3 I5—17 20-21 25 33—36.

96 LAND AND FRESH-WATER SHELLS.

Wales 41 45-46 50. Eng. N. 53—55 62 64 71. Scot.
Jones) 1e0. Irel.. Say wen ac!
Limax agrestis L. One hundred counties.
Eng. S. 1 2 4—6 8—13 15—21 24-25 28—40. Wales
41-42 45—52. Eng. N. 53—67 69—71. Scot. 72 75—85
87-88 90 92 95-96 98—I10I 103 I05—110 112. Irel. 114
116 119 124-326-127 136 430 “145.
Limax levis Mill. Twenty-two counties.
Fng.S. a 1n 13 16 21 39.° Wales’ 51." Eugenio
58 62—66. Scot. 76 95 98 100-101 107—109. No records
for Ireland.
Limax flavus L. Thirty-four counties.
Eng. S. 1 5-6 11—13 I5—I17 20-21 25 29-30 33 37
—4o. Wales 45 47. Eng. N. 54—56 61—64 66.
Seo. 76. Irel.- 124-9270 45. 247-
L. cinereo-niger Wolf. Thirteen counties.
Eng. S. 13 39-40. Wales 48. Eng. N. 62 64. Scot.
90.00 207. Irel; 128 126 41326 2454146.
L. maximus Auct. Seventy counties.
Eng. S. r 4-5 8-9 11—13 15—17 19—2I 24-25 28
39 32—34 36— 40. Wales 45—50 52. Eng. N. 53—59
61—66 69. Scot. 75-76 78—83 85 88 90 98—Io0o 107.
irel. \aaq 2i6 B24. 132 23012 73 as 4s:
Limax arborum Bouch. Forty counties.
Eng. S. 1.2 9 11-—13 18 20 23 24: 33-24 36-30)
Wales 45 48—so. Eng. N. 54 56—58 62---66. Scot.
8r-88.107 roo. \ Irel.. 115 118 :136°133. 142 1454s.
Succinea putris L. Fifty-six counties
Eng. 8. 0-1 6 LI—I7 19—21 23—25 27 29 31-35
37-40. Wales 41 44-45 49—52. Eng. N 53—59 61—67
69. Scot. 73 76 78 89-90. Irel. 144 148.
S. elegans Risso. Twenty-three counties.
Eng. S. © 6) 20-11-13 $i5—17 "| 20-21 “25ege eee
Wales 44-55 50. Eng. N. 56 58 61—64. No records
from Scotland or Ireland.
S. virescens Morel. Three counties.
Eng. S. 16 21 37. No records from Eng. N., Wales,
Scotland, or Ireland.

CENSUS. 97

S. oblonga Drap. Four counties.
Wales 41. Eng. N. 62. Scotland 34. Ireland 147.
No records for England S.
Vitrina pellucida Mill. Sixty-eight counties.
Eng? S. 1 3-4 6 11 13—17 20 22 23 25 27-28 32—34
36—40. Wales 41 45 47 49 52. Eng. N. 54—59 61—67
69 71. Scot. 75—83 85 89 g0—92 98—IOI 107 109.
Trel. 114 132 138 144. «
Zonites cellarius Mill. Eighty-eight counties.
Eng. S. o—9g 11—13 16—18 20—22 25 27—30 32—
40. Wales 41 43 45 47—52. Eng. N. 53—59 61—67
69 71. Scot. 73 75—85 89—92 98—I10I 105 107 109.
Trel. 114 118 124 132 138 144-145.
. alliarius Miller. Forty-four counties.
Fug, Si /o-1..6 E5, 1316-07 | 20.22) 42—-36)) 30, Ac.
Wales 45 47 49—52. Eng. N. 54 56—58 61—67 69 71.
Scot. 85 88—go 107 109 112. Irel. 113 144.
Z. glaber Stud. Twenty-four counties.
ling. S. 1 16-17 20—22 30 32 40. Wales 44 47 49-50
52. Eng. N. 55—60 63—66. No records for Scotland
or Ireland.
Z. nitidulus Drap. Sixty-eight counties.
Eng. S. o-1 4 6 8—r3 15—18 20-——-24 29 32—40.
Wales 41 43—45 47—52. Eng. N. 53—67 69. Scot. 73 76
83 85 89-90 98 102 104 109. Ireland. 113 138 144.
Z. purus Ald. Thirty-seven counties.
Eng. S. 1 8 11 16-17 19-20 22 25 29 32 34-37 39.
Wales 49 50 52. Eng. N. 56—59 62—67 69. Scot. 73 89-
go 107 109. Irel. 113 144.
Z.radiatulus Ald. Twenty-one counties.
Eng. S. 6 13 17 21 32 34-35. Wales 48 52. Eng. N.
56—s8 62—67 70. Scot. 89 109. No records for Ireland.
Z. nitidus Mill. Twenty-four counties.
Eng. S. 6 11 13 16-17 20—22 25 34-35 39-40. Wales
AI 51-52 Eng. N. 54 56—59 62—64. No records for Scot-
land or Ireland.

N

7

98 LAND AND FRESH-WATER SHELLS.

Z. excavatus Mill. Thirteen counties.
Eng. 5. 3,0nRea3 234 Wales 45 48. sue. hae
63-64 66. Scot. 100. ‘Irel. 124.
Z.crystallinus Mill. Forty-five counties.
Eng. S. 3 6 11—13 16-17 I19—22 25 32—34 36 39.
Wales 47 49—52. Eng. N. 54—67 69. Scot. 73 76 go
107, 1009.) Irel. 13°44 148.
Z.fulvus Mill. Fifty counties.
Eng. S. 7 11—13 17 20 22 25 27 32-33 36—40. Wales
AI 45 47—52. Eng. N. 54 56—59 61—66 69-70. Scot.
76 83 88—go0 98 I100-Io1 107 Iog. Irel. 113-114 118 148.
Helix lamellata Jeff. Eleven counties.
Eng N. 57 62—64 66-67. Scot. 72 88 98 107. Irel.
148. No records for Wales or England South.
H. aculeata Mill. Thirty-three counties.
Png. 5. 9 11 14 16-17(20 22-23 32-3340, Walesa
49 52. Eng. N. 56—60 62—66 69. Scot. 75-76 89-90 107
Fog: /lrele Tra" 146:
H. pomatia L. Eight counties.
Eng. S. 12-13 15—17 23 30 33. No records for Wales,
England N., Scotland, or Ireland.
H. aspersa Mill. Seventy-seven counties.
Eng. o—6 8—21 23—25 27—37 39-40. Wales 41-42
44—52. Eng. N. 53—58 60—71. Scot. 73 82-83 85 89-
go 94. Irele 214. F19/124, 744.
H.nemoralis L. One hundred and three counties.
Eng. S. o—6 8—25 27— 40. Wales 41-42 44—52.
Eng. N. 53—69 71. Scot. 73 75-76 78—83 85-86 88 go 92
96 98—103. Irel. 114-115 118-119 124-125 131-132, 136
138-139 141 144 148.
H. hortensis Miill. Seventy-nine counties.
Eng. S. 1—6 8—23 25 28—4o. Wales 41—45 47-48
50. Eng. N. 54—59 61—67 69. Scot. 73 75—77 81-82
85 88—9g0 97 99 102-103 107—109. Irel. 118 124-125 132.
H.arbustorum L. Fifty counties.
Eng. S. 2 6 10-11 13—17 20—23 25 31—37 39. Wales
4 43—45 49-50. Eng. N. 53-54 56-57 59 61—67 69. Scot.
72 77 88 90 98 107—109 112. No records for Ireland.

CENSUS, 99

. cantiana Mont. Thirty-seven counties.

Eng. S. 0 5-6 I0—20 22-23 25 27—30 32 34 36—38.
Wales 41. Eng. N. 54—56 61—67. No records for Scot-
land or Ireland.

. carthusiana Mill. Three counties.

Eng. S. 13—15.

. rufescens Penn. Sixty-three counties.

Eng. S. 1—17 19—24 26 28—30 32—35 37 39-40.
Wales 41 44-45 48—52. Eng. N. 54 57—65 69-70.
scot. 76 98-99. Irel. 113 119 124 144 146 148.

. concinna Jeff. Thirty-three counties.

Eng. S. 0 6 8 If I4—17 20—24 31—34 38-39.
Wales. 45. 49-50 52. Eng. N. 53 56-57 62 64-65 -6%.
Scot. 73 77 89. No records for Ireland.

. hispida L. Fifty-eight counties.

Eng. S. 0-1 6 8-9 11—18 20-21 23-24 29—36 39-40.
Wales 41-42 47—52. Eng. N. 53—67 69 71. Scot. 73
76 88—go. Irel. 141.

. sericea Mill. Thirty counties.

Eng. S. I—3 II-I2 15 20-21 29 32—34. Wales 44-
45 49—52. Eng. N. 56 62 64—67 69. Scot. 76 go 98
mot Enel, £25.

. reveiata Mich. Four counties.

ine, S.. O——3,. - No records for, Scotland,,. Wales,
Ireland, or England N.

. fusca Mont. Twenty-four counties.

Eng. S. 3 11 13 34 36 39. Wales 47—49. Eng. N.
57.50 O2—64 66-67. Scot. 73 75. 80-107, Irel. 114 118
138 145.

. pisana Mill. Five counties.

Eng. S. o-1. Wales 45.: Ire. 123-124. No. records
for Scotland or North of England.

. virgata DaCosta. Fifty-eight counties.

Eng. S., o—1I 13—23 25 27—29 31—34 37-38.
Wales 41 44-45 49—52. Eng. N. 53—57 60—-64 66.
peat 752 lrel, 114 124-125 130) 144. 148.

. caperata Mont. Sixty-four counties.
Eng. S. o-1 3-4 6 9—23 25 32—34 36—40. Wales

100 LAND AND FRESH-WATER SHELLS.

At’ 44-45 48-52. Eng. N. 53-59 61-07" GO ge
Scot.” 75-70 33.35 90 too 207.” Trel "1137124 744
H. ericetorum Miill. Sixty counties.
Eng. S. 1 6—8 I1—1I7 19-20 22-23 27-30 32—34
37—40. Wales 41 44-45 50 52. Eng. N. 53-57 61—67
WI. Scot. 85 67 Too 103 To7-106 aio, Trelis
[0O 024 027 131 130 241 144:
H. rotundata Miill. Eighty-six counties.
Eng. S. 0-1 4 6—1I 13—I7 20—23 25 247-28 30
32-347 30-40. Wales’ 41°43 45 47—52. | Hinge
53—-r9 61—67 69—71. Scot. 73 75—79 81—85 88—91
97—I101 105 107 10g. Irel. 113-114 118.124 132 136 144.
H. rupestris Dp. Thirty-six counties.
Eng. S. 0-1 3°69 Il 13-15, 20 22-2342 aaa
39. Wales 41 49-50 52. Eng. N. 57 60 62 64—66
69—71. Scot. 89. Irel. 124 132 144 146 148.
H. pygmza Dp. Twenty-two counties.
Eng. 6S. 31 15.723 32-33 39: | Wales’ 50. “inge aa
54 56 58 61 64—67 71. Scot. 89 105 107109. Irel.
ri.
H. pulchella Mill. Forty-five counties.
Eng. S. 0-1 6 If 13—16 19 22-23 25 29 32—36
39. Wales 41 49—52. Eng. N. 53--57’59 61-66 60,
Scot. 83 85 89—g1 107. Irel. 139 144.
H. lapicida L. Thirty-four counties.
Eng. S. 476.9 11—13 15--10 22—24 27) 30032
39. Wales 41 43. Eng. N. 53 56-57 59 61—65. No
records for Scotland or Ireland.
H. obvoluta Mull. Three counties.
Eng. S. 11—13. No records for Wales, Ireland, Scot-
land, or North of England.
Bulimus acutus Mill. Twenty-five counties.
Eng. S. 0-1 3-4 6 9-10. Wales 41 44-45 50—52.
ng. N. 58 71. Scot. 103. rel. 93-114 919 ae
132 134 139 144.
B. montanus Pp. Five counties.
Eng. S. 6 23 26 33-34. No records for England
N., Wales, Scotland, or Ireland.

CENSUS. IOI

B. obscurus Mill. Fifty-four counties.
Mig..." 0-8 (3-4 6 Q TE—I7 .19-20 22-23 27—-30
32—36 38—40. Wales 41 50 52. Eng. N. 53-54 56—67
69. Scotland 77 81 83 88—g1. No records for Ireland.
Pupa secale Dp. Sixteen counties.
Eng. S. 6 g-1o 12—15 22-23 33—35. Eng. N. 57
64-65 69. No records for Wales, Scotland, or Ireland.
P. ringens Jeff. Fourteen counties.
Eng. S. 0 36. Wales 52. Eng. N. 56 61-62 64 66-67.
Scot. 76 ror 107-108. Irel. 148.
P. umbilicata Dp. Sixty-four counties.
Eng. S. o—3 6 g I1—I17 21—23 25 32—34 37—40.
Wales 41 44-45 47 49—52. Eng. N. 54 56—67 69—71
Scot. 73 75 83 85 89-90 98 107—109. Irel. 119 139
144 146—148.
P. marginata Drap. Thirty-seven counties.
Hees). Pid) G6) gi TO 2U) 28h 25). 325-34). 3a
Wales 49—51. Eng. N. 54 56—58 61—64 66-67 71.
Irel. 139 144 148. No records for Scotland.
Vertigo antivertigo Dp. Nineteen counties.
Eng. S. 4 10-11 17 22-23 25 33-34. Wales 50. Eng.
N. 56-57 59 62—64. Scotland 81 107. Ireland 124.
V. lilljeborgi Westerl. One county.
Irel. 139. No records for Eng. Wales, or Scotland.
V. moulinsiana Dup. non Jeff. One county.
Eng. S. 20. No records for England N., Wales,
Scotland, or Ireland.
V. pygmea Drap. Thirty-four counties.
Eng. S. 4 6 10—15 17 21 23 25 27 30 32—34 38.
Wales 49. Eng. N. 54 56-57 62—67. Scot. 76 83 107
z09-, -Irel... 113) 145.
V. alpestris Ald. Four counties.
Bue. N. 62.67.60, Irel.- 123.. No. records: for
England S., Wales, or Scotland.
V. substriata Jeff. Five counties.
Wales) sa Ene. N.. 57 .63. 66... Irel.. 113.5 ¢20
records for England S., or Scotland.

102 LAND AND FRESH-WATER SHELLS.

V. pusilla Mill. Ten counties.
Eng. S. 4 23. Eng. N. 56-57 63-64 66-67. Scot.
75. drel.: 113: No: records for Wales.
, tumida Westerl. Not seen.
. angustior Jeff. Six counties.
Pog. N. 577645 “Scot. roy. © Irel;193 4860 30a
No records for England S. or Wales.
V. edentula Drap. Thirty-five counties. }
Eng.0S. 4-41 ¢0 23 28 32-—34- 37 3041 PWalesie
52. Eng. N. 54 56-57 60 62—64 66-67 69. Scot. 76 81
89—9QI 100-I0I 107—I09. Irel. 113-114 148.
V. minutissima Hartm. Five counties.
Eng... S.\ 10.) ng: N. 63°66: Scot.433. treba aa
No records for Wales.
Balea perversa L. Forty-one counties.
Eng. S..© 3-4. 6-7 10—14 "22 25 (27 32°33) 36 44
Wales» 41.45: 49-50. Eng. N. 54-55 57—60) 62 G45G5
69—71. Scot. 73 75-76 83 89.98 ror Too. | Irel. 14a:
Clausilia rugosa Drap. Eighty-nine counties.
Eng. S. o—4 6—g 11-25 27—30 32—40. Wales ,
4I—45 47—52. Eng. N. 53—67 69—71. Scot. 73 76
83 88—go0 98 100-101 103 107—I10g. Irel. 113-114 124
132 138-139 144 146—148.
C. rolphii Gray. Nine counties.
ding. S. 12—17 22 33. Eng. N. 56. No records
Wales, Scotland, or Ireland.
C. biplicata Mont. Three counties. .
Eng. S. 17 20-21. No records for Wales, England
N., Scotland, or Ireland.
C. laminata Mont. Thirty-five counties.
Eng. S. 6 9 I1I—17 20 22-23 25—27 32—34 36 39.
Wales 41. Eng. N. 53-54 56—58 61—67 69. Scot. 89.
No records for Ireland.
Cochlicopa tridens Pult. Twenty-two counties.
Eng. S. 161417 23 30 33-34 3739. Wales 48. Eng.
N. 56—58 62—67 69. No records for Scotland or Ireland.
C. lubrica Mill. Eighty-five counties.
Eng. S. o—2 4 6—8 10—23 25 27—-30 32-—-40.

<<

CENSUS. 103

Wales 41 43 45 47-52. Eng. N. 54—67 69 71.
Scot. 73 75—77 79—83 85 88—go0 98 I00 105 107—109.
Irel. 113-114 132 139 144 148.

Achatina acicula Mill. Eighteen counties.

Eng. S. 6 8—10 14-15 17 19 23 32 34 36. Eng. N.
56-57 62—64 67. No records for Wales, Scotland, or
Ireland.

Carychium minimum Mill. Fifty counties.

Eng. S. 6 11 13—17 I9—23 25 27-28 32—34 36
39. Wales 41 48—52. Eng. N. 54 56—59 61—67 69.
Scot. 73 76 89—g1 98 101 107. Irel. 113 144 148.

Cyclostoma elegans Miill. Twenty-five counties.

Eng. S. 3-4 6 9 II1—1I7 20 22-23 29-30 33 35-36.
Wales 41 45 50. Eng. N. 62 64 69. No records for
Scotland or Ireland.

Acme lineata Drap. Eleven counties.

Eng. S. 6 15 23. Eng. N. 57 60 62—64 66. Scot.
Fo. Irelz “148.

Spherium corneum L. Sixty counties.

Eng. S. 6-7 9 11—25 27—30 32—34 37—40. Wales
At-42 45 47 52. Eng. N. 53—67 69. Scot. 73 76 81
83 88—go 112. Irel. 115 144.

S. rivicola Leach. Nineteen counties.

Eng. S. 6 17 21—23 32—34 37 39. Eng. N. 53
56—59 62—64 67. No records for Wales, Scotland, or
Ireland.

S. ovale Fér. Seven counties.

Eng. S. 17 21 38. Eng. N. 59 62—64. No records
for Wales, Scotland, or Ireland.

S. lacustre Mill. Thirty-three counties.

Eng. S. 3 6-7 II—-13 I5—I7 19 21 27-28 32 34
37—40. Wales 41 44 49-50. Eng. N. 55—57 59 61—64
66-67. No records for Scotland or Ireland.

Pisidium amnicum Mill. Twenty-nine counties.

Eng. S. 6 11 13 17—24 27—29 38-39. Wales. 42.
Eng. N. 53 55—65 67. No records for Scotland or
Ireland.

104 LAND AND FRESH-WATER SHELLS,

P. fontinale Drap. Forty-two counties.
Eng. S. o-1 6-7 9—13 17 21 28 30 32—34 37-38
40. Wales 41 44-45 47. Eng. N. 53 56—67 69. Scot.
300 Tet, 108: rel. aaa.
P. pusillum Gmel. Fifty-two counties.
Eng. S.. 0-1 .4° 6-7 0 TI—=17, 21 23 26 12830 32-32
36-37 39-40. Wales 41-42 45 47. Eng. N. 53—59 61—
64 66-67 69-70. Scot. 73 78 81 go 101 105 107-108.
Trel. 144.
P. nitidum Jen. Twenty-four counties.
Eng. S. 6 10-11 16 23 28 37-38. Wales 41-42. Eng.
N. 54 56—59 61 63—65 67. Scot. 85 94 112. Irel.
F132,
P. roseum Scholtz. Thirteen counties. |
Eng. S. o £1 15 17 20-21 30 40. Eng. N. 5o-g7 ee
66. Scot. 85. No records for Wales or Ireland.
Unio tumidus Phil. Twenty-one counties.
Eng. S. 6 21—23 30 32 34 37—-39. Wales 47.
Eng. N. 53—57 59 61—64. No records for Scotland or
Ireland.
U. pictorum L. Twenty-four counties.
Eng. S.- 6.8 17 21-22) 27 ‘20-30°32 37-30.) Wales
47. Eng. N. 53—59 62—64 68. No records for Scot-
land or Ireland.
U. margaritifer L. Sixteen counties.
Wales 45 49-so. Eng. N. 62:67 71. ‘Scot, 76-77
87-88 go 98 108. Irel. 126 144-145. No records for
England S.
Anodonta cygnea L. Forty-one counties.
Ing. S...8 a21°17-18 20. 25-29-28 20 32——em
37—40. Wales 42 45. Eng. N. 53—67. Scot. 76 go.
frel.. 125.
A. anatina L, Twenty-five counties.
Eng. S. 6 15-16 20—22 27 32-34 38—40. Wales
45. Eng. N. 55—59 61—65 67. Scot. 83. No records
for Ireland.
Dreissena polymorpha Pall. Twenty-three counties.
Eng. S. 6 17 21—23 29 31—34 37—40. Eng. N.

CENSUS. 105

55—59 63-64. Scot. 76-77. No records for Wales or
Treland.

Neritina fluviatilis L. Thirty-two counties.

Eng. S. 3 6.9 I1 13-14 16 18-19 21—24 27 29 32
37—39., Hing, (N. 53. 55-57 60—65. Scot. 76 IIT.
Irel. 131. No records for Wales. .

Paludina contecta Millet. Nineteen counties.

Eng. S. 11 22—24 27—29 31-32. Eng. N. 53—56
58-59 61—64. No records for Wales, Scotland, or Ireland.

P. vivipara L. Twenty-eight counties.

Eng. S. 16—18 20—23 25 27 3I—35 37—40. Eng.
N. 53 55—59 61—64. No records for Wales, Scotland,
or Ireland.

Bythinia tentaculata L. Fifty-four counties.

Eng. S. I 4—7 9—I2 15—25 27—39 32—34 37—40.
Wales 41-42 47. Eng. N. 53—67. Scot. 76. Irel. 113
115 142 144.

B. leachii Shepp. Twenty-eight counties.

} Nng. 5. 6°16 14—16. 19 21:23 25 27-—29 °32—34
39-40. Wales 45. Eng. N. 53-54 56-57 59—64. No
records for Scotland or Ireland.

Valvata piscinalis Mill. Fifty counties.

Eng. S. 1 6 9 11-12 I5—25 27-28 32—34 38—40.
Wales 41 45 52. Eng. N. 53—57 59—67 71. Scot. 73
76 83 85 89-90. Irel. 142—144.

V. cristata Mill. Thirty-two counties.

Eng. S. 6 11—19 21—23 25 27-28 32. Wales 41-42
45. Eng. N. 54 56-57 59 61—64 66-67. Scot. 73 77
go. No records for Ireland.

Planorbis lineatus Walk. Eleven counties.

Eng. S. 14—17 21—23 27-28. Eng. N. 60-61 64.
No records for Wales, Scotland, or Ireland.

P. nitidus Mill. Thirty counties.

Bg. 5. 6-7 Gla bs 26-17 Io) 2b 27-28) 31 37-—ae
Wales 41. Eng. N. 53 55-56 58-59 61—64 67. Scot. 76
Sho lhe, TAZ): 147.

P. nautileus L. Thirty-six counties.

PMS. 20g: 1. TO i19)2 E123) 27-28 30 32 37—3a,

106 LAND AND FRESH-WATER SHELLS.

Wales 41. Eng. N. 53-54 56—65 67. Scot. 73 76-77 82
85 90 100. No records for Ireland.
P. albus Mill. Fifty-three counties.

Eng. 8. 3 6-7 I0-II 13 I15—1I9 21—23 25 27-28 30
32—35 37—40. Wales 41 45 47 52. Eng. N. 53—65
67 71. Scot. 73° 7o.6285 ioe: root rel; 144 Sea

P. parvus Say. ‘Twenty-three counties.
Eng. 8. 3.6 9 13 17-18-21 23 338: ‘Eng: Now5— 57a
63 65—68. Scot. 82 90 108. Irel. 114 144. No records
for Wales.
P. dilatatus Gld. One county.
Eng. N. 59. Norecords for Wales, Scotland, or Ireland.
P, spirorbis Mill. Fifty-two counties.

Eng. S. o-r 6-7 10—13 16 18—23 27—29 32-33
37—40. Wales 41-42 45 48 52. Eng. N. 53—64 66-
67.) scot, 173:°76 .8690'192..102 )nod.,; rel. eg oeaee

F. vortex i. | Forty-five counties.

Eng. S. 0 3 6-7 9 I 13 I5—25 27—29 32-34
37—40. Wales 41 42 47. Eng. N. 53—59 61—64.
Scotego. (rel) 132/442.

P. carinatus Mill. Forty-three counties.

Eng. S.-6 9—II 15 17—-25 27—29 32——-34 37—
39. Wales 41-42. Eng. N. 53—59 61—66. Scot. 33.
Incl s aws) 091) 42,

P. complanatus L. Forty-eight counties.

Eng. S. 5—7 II 13—I17 19—30 32—34 37—40.
Wales 41-42. Eng. N. 53—57 59—67. Scot. 83. Irel.
131 142 144. .

P. corneus L. Thirty-five counties.

Eng. 8S. 6 If 13 I5—17 20—24 27—-34 37—39.
Eng. N. 53—59 61—65. Irel. 142. No records for
Wales or Scotland.

P. contortus L. Forty-four counties.

Eng. S. 6-7 10-11 13 15—17 19—23 27=-30 32-33
37—39. Wales 52. Eng. N. 53—64 66. Scot. 73 85
89-90 92 100. Irel. 142 144.

Physa hypnorum L. Thirty-two counties.
Eng. S. 0 6 11 16 19 29 34 37—40. Wales 41-42

CENSUS. 107

ae ica. ane) NOY 92467. \.'Scot.. Sr -reg) Irely) 146
148.
P. fontinalis L. Fifty-three counties.
Hoe: i. 609 IE 13° .15—17 19-—23 525. 27—30
32-33 37—40. Wales, 41-42 45 52. Eng. N. 53—59
61—64 66-67 69 71. Scot. 73 76-77 83 85 89-90 I0o.
. frel) 142 144 148.
Limneza glutinosa Mill. Eight counties.
ia. eer mor 22 a4 29. °-Nne Ne 62 69. .Itel., 115
131. No records for Wales or Scotland.
L. involuta Thomps. One county.
Confined to county Kerry (No. 148).
L. peregra Mill. Ninety-six counties.
Eng. S. o-t 4—8 10—34 36—40. Wales 41-42 44-45
48—so 52. Eng. N. 53—71. Scotland 72-73 75—-83 85
88—o90 92 98 I00-IoI 103 105 107-108 110 112. Irel.
I13—I15 131 141-142 144 148.
L. auricularia L. Forty-six counties.
Bog. 5S: 6-7 11 13 15-18 \21—25 27-26 30° 22-34
37—40. Wales 42 44 52. Eng. N. 53—59 61—64 66-
67. Scot. 73 76 81-83 85. Irel. 142.
L. stagnalis L. Forty-eight counties.
Bug .S. 5-04-9412 £31517 10—25 “27-40 se
34 37—40. Eng. N. 53—59 61—67. Scot. 77. Irel.
115 136 142. No records for Wales.
L. palustris Mill. Seventy counties.
Eng. S. 0 1 6-7 9 11—23 25 27—29 31—34 37—40.
Wales 41-42 45 47 52. Eng. N. 53—67 69—71. Scot.
72 46-77 85 88—o90 93. Irel. 113 115 124 131 136
142 144-145 148.
L. truncatula Miill. Seventy-four counties.
Eng. S. 1 3-4 6 9—II 13 15—I9Q° 21—23 25 27-28
30—34 36—40. Wales 41 44 47—50 52. Eng. N.
53—67 69—7:. Scot. 73 75—77 85 89—9I I00-101
103-104 107—I09. Irel. 113 139 141-142 144.
L. glabra Mill. Twenty-two counties.
Eng. S. o tr’ 16 19°37 30-40. Wales 47-48. “Eng.
N. 53 59 61—67 69-70. Scot. 77. Ireland 147.

108 LAND AND FRESH-WATER SHELLS.

Ancylus fluviatilis Mill. Sixty-seven counties.
Eng. S 1-2 4 6 8-9 11 13—17 19-20 23 28 32 34—40.
Wales 41 44-45 47—50 52. Eng. N. 54—59 61—65 67
69—71. Scot. 73 75-76 78-79 89-90 92 98—I0I 104
fO6s/* lréls Tig; 5 224136. 14207144.
A. lacustris L. Forty-one counties.
Eng. S. 6-7 11 16 19 21—23 27—34 37—40. Wales
N. 41.45. Eng. 54—67. Scot. 73 85 90. Irel. 124 142.

—-

It will be seen on perusal of the above census that the
‘ principal places to be regarded as among the uninvestigated and
“dark corners” of the kingdom are Scotland and Ireland, Mid-
Wales, and the eastern and south-western counties of England,
specimens from any of which districts will be of unusual value
and importance.

KEY TO THE ABOVE.

o, Channel Isles ; 1, Cornwall West, divided from Cornwall
East by the highroad from Truro through St. Columb to the
inland extremity of Padstow Creek; 2, Cornwall East; 3, Devon
South, divided from North Devon by the watershed line, which
commences at the Tamar, about midway between Tavistock and
Launceston, passes over the ridge of Dartmoor, and joins the
Western Canal at Tiverton ; 4, Devon North; 5, Somerset South,
divided from North Somerset by the River Parret from Bridge-
water to Ilchester, the line thence curving round to the N.
extremity of Dorsetshire; 6, Somerset North; 7, Wilts.
North, separated from Wilts. South by the Kennett and
Avon Canal; 8, Wilts.. South; 9, Dorsetshire’; ao, islegee
Wight ; 11, Hants South, divided from Hants North by the high-
roads running W. and E. to the borders of Wilts and Sussex
respectively, through Stockbridge and Petersfield; 12, Hants
North; 13, Sussex West, divided from East Sussex by the
high-road from Brighton to Cuckfield, thence through Crawley
to the Surrey border; 14, Sussex East; 15, Kent East, divided
from W. Kent by the Medway and its tributaries from its mouth
nearly up to Staplehurst, thence the line is along the high-road

CENSUS. 109

through Cranbrooke to the Sussex border near Hawkeshurst ; 16,
Kent West ; 17, Surrey; 18, Essex South, divided from North
Essex by the highroad from Waltham and Epping to Chelmsford,
thence along the river Blackwater to its mouth; 19, Essex North;
20, Hertfordshire ; 21 Middlesex; 22, Berkshire; 23, Oxfordshire ;
24, Buckinghamshire; 25, Suffolk East, divided from West
Suffolk by the parallel of longitude 1° East from the meridian
of Greenwich; 26, Suffolk West: (the detached portion upon
which Newmarket stands is included with Cambridgeshire) ; 27,
Norfolk East, divided from West Norfolk by the 1° East parallel
of longitude; 28, Norfolk West; 29, Cambridgeshire, including
the Newmarket detached portion of Suffolk ; 30, Bedfordshire,
including a detached portion of Huntingdonshire ; 31, Hunting-
donshire; 32, Northamptonshire; 33, Gloucestershire East,
separated from West Gloucestershire by the Thames and Severn
Canal, thence by the River Severn from the point of confluence
of the canal up to Tewkesbury, and includes five detached portions
of Worcestershire and one of Warwickshire; 34, Gloucesterhire
West ; 35, Monmouthshire (a detached portion is included in
Herefordshire) ; 36, Herefordshire, including detached portions
of Monmouthshire and Worcestershire (detached portions of
Herefordshire are on the other hand included in Brecknockshire,
Radnorshire, Shropshire, and Worcestershire); 37, Worcester-
shire, including detached portions of Herefordshire, Shropshire,
Staffordshire, and Warwickshire (detached portions of this
county are, on the other hand, included with Gloucestershire,
Herefordshire, and Staffordshire); 38, Warwickshire (detached
portions are included in Gloucestershire and Worcestershire) ; 39,
Staffordshire, including a detached portion of Worcestershire,
which in its turn includes an outlier of Staffordshire; 40, Shrop-
shire, including an outlier of Herefordshire (a detached portion
of Shropshire is included with Worcestershire; 41, Glamorgan-
shire; 42, Brecknockshire, including a detached portion of
Herefordshire ; 43, Radnorshire, including a detached portion of
Herefordshire; 44, Carmarthenshire; 45, Pembrokeshire; 46,
Cardiganshire; 47, Montgomeryshire; 48, Merionethshire; 49,
Carnarvonshire (the Llandudno peninsula and other portions of
this county lying East of the river Conway are included

IIo LAND AND FRESH=WATER SHELLS.

with Denbighshire) ; 50, Denbighshire, including outliers of the
county last named, also the detached portion of Flintshire; 51,
Flintshire (the detached—or Overton—portion is included with
Denbighshire) ; 52, Anglesey; 53, Lincolnshire South, divided
from North Lincoln by the Witham from its mouth at Boston
to Lincoln, thence by the Foss Dyke to the border of Nottingham-
shire; 54, Lincolnshire ‘North; 55, Leicester and Rutland;
including a detached portion of Derbyshire; 56, Nottingham-
shire; 57, Derbyshire (a detached portion is included with
Leicester and Rutland); 58, Cheshire; 59, Lancashire South,
separated from West Lancashire by the River Ribble; 60,
Lancashire West (the Furness district of North Lancashire is
included with Westmorland); 61, Yorkshire South-East, being
the East Riding of Yorkshire; 62, Yorkshire North-East, divided
from N. W. Yorkshire by the Rivers Wiske and Swale ; 63, York-
shire South-West, equivalent to the Southern division of the West
Riding, divided from Mid-West Yorkshire by the Leeds and
Liverpool Canal and by the River Aire below Leeds; 64, York-
shire Mid-West, equivalent to the Northern portion of the West
Riding minus the Dent and Sedbergh district, which is included with
North-West Yorkshire; 65, Yorkshire North-West, equivalent to
the western half of the North Riding with the addition of the
Dent and Sedbergh district of the West Riding; 66, Durham (the
detached portions are included with Northumberland and Cheviot-
land) ; 67, Northumberland South, includes a detached portion of
Durham, and is separated from Cheviotland by the River Coquet
and a line continued to Carter Fell from the Linn bridge;
68, Cheviotland, equivalent to North Northumberland plus a
detached portion of Durham; 69, Westmorland and Furness ; 70,
Cumberland; 71, Isle of Man; 72, Dumfriesshire; 73, Kirkcud-
brightshire ; 74, Wigtonshire; 75, Ayrshire; 76, Renfrewshire ;
77, Lanarkshire; 78, Peeblesshire; 79, Selkirkshire ; 80, Rox-
burghshire ; 81, Berwickshire ; 82, Haddingtonshire; 83, Edin-
burghshire ; 84, Linlithgowshire; 85, Fife and Kinross; 86,
Stirlingshire, including the detached portion of Dumbartonshire ;
87, Perth West and Clackmannan, separated from Mid-Perth by
the line of watershed which divides tributaries of the Tay from
those of the Forth; 88, Perth Mid, separated from East Perth by

CENSUS. ig

the rivers Garry and Tay; 89, Perth East; 90, Forfarshire ; 91,
Kincardineshire; 92, Aberdeenshire South, separated from N.
Aberdeen by the watershed line which runs E. and W. from
Inverury ; 93, Aberdeenshire North; 94, Banffshire; 95, Elgin-
shire, including the detached portion of Inverness-shire which
separates the two portions of Elginshire; 6, Easterness (to
form the vice-counties “‘ Easterness ” and “ Westerness,” Inverness-
shire is first divided by the line of watershed between the East
and West of Scotland, continued along Loch Erricht to the Perth-
shire border, the Eastern portion—with Nairnshire added—being
called Easterness, and the Western portion—with the detached
portion of Argyleshire situated N. W. of Loch Linnhe—is called
Westerness) ; 97, Westerness (see 96 for definition) ; 98, Main
Argyleshire, is what is left of the county after the separation
of Cantire, the Islands, and the portion N. W. of Loch Linnhe ;
99, Dumbartonshire (the detached portion is included with
Stirlingshire); 100, Clyde Islands, Bute, Arran, Cumbray, and
Ailsa Craig; 101, Cantire, this peninsula is separated from
Argyleshire by the Crinan Canal; toz, Ebudes South, the
Islands of Jura, Colonsay, and Islay; 103, Ebudes Mid, the
Islands of Mull, Coll, Tirree, Staffa, Iona, etc.; 104, Ebudes
North, the Islands of Skye, Canna, Rum, Muck, Eig, etc. ;
105, Ross-shire West, separated from East Ross-shire by the
watershed parting East and West Scotland, and including some
of the fragments of Cromarty county; 106, Ross-shire East,
including fragments of Cromarty and Nairnshire; 107, Suther-
land South-East, divided from North-West Sutherland by
the watershed line parting the East and West sides of Scotland ;
108, Sutherland North-West; 109, Caithness ; 110, Hebrides ;
111, Orkneys ; 112, Shetland Islands ; 113, Londonderry County
(the city of Londonderry is included with Donegal county); 114,
Antrim County; 115, Down County; 116, Armagh County ;
117, Monaghan County; 118, Tyrone County; 119, Donegal
County, including Londonderry City ; 120, Fermanagh County ;
121, Cavan County; 122, Louth County; 123, Meath County ;
124, Dublin County; 125, Kildare County; 126, Wicklow
County; 127, Wexford County; 128, Carlow County; 129, Kil-
kenny County ; 130, Queen’s County’; 131, King’s County; 132,

ae

I1I2 LAND AND FRESH-WATER SHELLS. !

Westmeath County; 133, Longford County ; 134, Roscommon
County ; 135, Leitrim County; 136, Sligo County; 137, Mayo
East, separated from West Mayo by the railway from Ballina to
the head of Lough Mask; 138, Mayo West; 139, Galway West,
separated from East Galway by Lough Corrib; 140, Galway East ;
141, Clare County; 142, Limerick County; 143, Tipperary
North, divided from South Tipperary by the line of watershed ;
144, Tipperary South; 145, Waterford County; 146, Cork
North, divided from South Cork by the River Lee; 147, Cork
South; 148, Kerry County.

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