beneath; the spire very much inclined towards the margin; the aperture
partly closed by a horizontal lamina. Inhabits the American seas.
Thirteen species.
Crepidula extinctorum.
C. aculeata.
C. lævigata.
C. uguiformis.
C. dilata.
C. Peruviana.
C. gigas.
· · · · ·
C. fornicata.*
C. depressa.*
C. glauca.*
C. plana.*
C. intorta.*
C. convexa.*
7. Genus _Ancylus_. Pl. X.
_Animal._ Body creeping, enveloped in the shell; two compressed
subtruncated tentacular, with eyes situated at their internal base; foot
short, elliptical; somewhat narrower than the body.
_Shell._ Thin, obliquely conical; aperture oval, with a pointed apex,
which very much inclines backwards; margins simple. This is a fresh
water shell, found in the lakes of Europe and rivers of America. Five
species.
Ancylus lacustris.
A. fluviatilis.
A. spinarosæ.
· · · · ·
A. rivularis.
A. filosus.
FAMILY IV.
BULLACEA. Three genera.
1. Genus _Acera_.
_Animal._ Body ovate, convex, transversely divided above into two parts;
the foot with dilations in the form of wings below; head indistinct;
branchiæ situated on the back, greatly behind, and covered by a mantle
destitute of a shell. Inhabits the Mediterranean. One species.
Acera carnosa.
2. Genus _Bullæa_. Pl. X.
_Animal._ Body ovate, somewhat convex above, and divided into two parts
transversely; lateral lobes of the foot very thick; head indistinct, and
without tentacula; branchiæ placed on the back.
_Shell._ Concealed in the mantle, very thin, rolled and spiral on one
side; without a columella and spire; aperture very large and wide,
dilated at the upper part. Inhabits the British seas. Two species.
Bullæa aperta.
B. striata.
3. Genus _Bulla_. Pl. X.
_Animal._ Body oblong-ovate, slight convexity; divided into two portions
transverse above, mantle slightly folded posteriorly; visible tentacula;
branchiæ dorsal and covered, opening only on the right side.
_Shell._ Univalve, ovate globular, convolute, no columella, spire not
projecting but visible, aperture the whole length of the shell, external
margin sharp and smooth. Inhabits the British and American seas.
Nineteen species.
Bulla physis.
B. naucum.
B. hydatis.
B. rugosa.
B. fragilis.
B. aplustre.
B. ampulla.
B. lignaria.
B. fasciata.
B. striata.
B. Wyatii.
B. solida.
B. cornea.
B. lactea.
· · · · ·
B. solitaria.*
B. triticea.*
B. hiemalis.*
B. Gouldii.*
B. lineolata.*
FAMILY V.
APLYSIACEA. Two genera.
1. Genus _Dolabella_. Pl. X.
_Animal._ Body creeping, oblong, narrowed in front; and posteriorly
widened; area round, sloping, and truncated obliquely; margins folded
over the back; four tubular tentacula, disposed in pairs; bronchial
operculum inclosing a shell; orifice dorsal, near the branchiæ.
_Shell._ Oblong, slightly arcuated, thick, callous, and somewhat spiral
on both sides, singular in formation, and its characteristic unlike most
other shells. Inhabits the Isle of France. Two species.
Dolabella Rumphii.
D. fragilis.
2. Genus _Aplysia_. Pl. X.
_Animal._ Body creeping, oblong, convex above; bordered on each side by
a broad mantle, which covers the back when the animal is in repose; head
and neck elevated, with four tentacula, the two upper ones ear-shaped,
eyes situated near the mouth; dorsal shield semicircular,
subcartilaginous, adhering on one side, and covering the branchial
cavity.
_Shell._ Nearly round, left margin somewhat reflected; outer lip acute;
yellowish horn colored, with brown radiations, and two concentric bands.
Inhabits the Indian seas. Thirty-seven species.
Aplysia depilans.
A. teremida.
A. gigas.
A. hassetlii.
A. punctata.
A. marmorata.
A. dolabrifera.
A. ascifera.
A. petalifera.
A. unguifera.
A. Limacina.
A. Jeachii.
A. saviguana.
A. fasciata.
A. bresili.
A. dactycomela.
A. protea.
A. sorex.
A. tigrina.
A. maculauta.
A. longicauda.
A. Kerandrenii.
A. lessonii.
A. camelus.
A. alba.
A. Napolitana.
A. viridis.
A. longicornis.
A. ecaudata.
A. virescens.
A. poliana.
A. fusca.
A. pleii.
A. citrini.
A. undata.
A. rosea.
A. Ferrusacii.
FAMILY VI.
LIMACINA. Five genera.
1. Genus _Limax_. Pl. X.
_Animal._ Cuvier merely mentions that the animal is “furnished with a
coriaceous, subrogose shield, with a flat, longitudinal disk beneath;
four tentacula retractile, eyes at the tips; orifice for respiration on
the right side.”
_Shell._ Ovate oblong, both margins reflected; very thin, diaphanous,
slightly wrinkled, of a pale yellow colour. Inhabits the gardens in
Britain and France. Five species.
Limax rufus.
L. cinerus.
L. albus.
L. agrestis.
L. punctata.
2. Genus _Vitrina_. Pl. X.
_Animal._ Body creeping, elongated, snail shaped, nearly straight;
posteriorly separated from the foot, and spirally wound into a shell.
_Shell._ Small, very thin, depressed, terminated above by a very short
spire, the last whorl very large; aperture large, rounded oval; the left
margin arched, slightly involute. Inhabits dry places of Europe. Three
species.
Vitrina parilis.
V. dentilis.
V. pellucida.
3. Genus _Testacella_. Pl. X.
_Animal._ Body creeping, elongated, snail shaped, having a shell placed
on the posterior extremity; four tentacula, the two longest with their
eyes at their tips; respiratory organs behind.
_Shell._ Very small, external, ear-shaped, apex absolutely spiral,
aperture very large and oval, left edge sharp and rolled inward behind.
Inhabits the middle provinces of France. Two species.
Testacella Haliotidea.
T. Neritoidea.
4. Genus _Parmacella_. Pl. X.
_Animal._ Body creeping oblong; middle of the back moderately convex,
and shield-shaped; hind part in form of a tail, laterally compressed,
acute above; shield ovate, fleshy, adhering at its posterior part, free
before, enveloping a shell, with a notch in the centre of its right
margin; four tentacula, two posterior largest; respiratory organs, under
the notch of the shield, placed between the two tentacula of the right
side.
_Shell._ Ovate, left margin broad and reflected; right margin reflected
at top and acute beneath; very thin and pellucid, of a pale
yellowish-brown. Inhabits the gardens of Europe. Two species.
Parmacella Olivieri.
P. Cuvierii.
5. Genus _Onchidium_. Pl. X.
_Animal._ Body oblong, creeping, marginated on all sides; head
projecting, the lower part with a prominent margin, two retractile,
cylindrical tentacula; two auriform appendages, nearly lateral; mouth
beneath, destitute of maxillary processes; respiratory orifices
distinct, under the extremity of the body.
Destitute of a shell. Inhabits the gardens of Europe. Two species.
Onchidium Typhæ.
O. Peronii.
FAMILY VII.
COLIMACEA. Eleven genera.
1. Genus _Helix_. Pl. X.
_Animal._ Of a slightly variable form, the mantle forming at its free
edge a kind of ring or thick collar, especially in front, and faintly
divided into two lips; foot oval, plane, smooth beneath, inflated and
granular below, joined to the visceral club by a narrow peduncle; head
sufficiently distinct; anterior tentacula very evident and inflated at
top, the posterior very long; the mouth a vertical cleft provided with
two labial lobes, a sort of marginal tooth, with a small, oval, lingual
club.
_Shell._ The name Helix was given to this genus from the spiral shape of
the shell, which varies much in form, but generally globular, and
ventricose, conoid but never turriculated; summit generally obtuse,
aperture varying much in size, sometimes very large, sometimes small,
always regulated by the turn of the spire; oval, semilunar, more wide
than long, edges disunited, entering little into the interior; right lip
or margin thickened or reflected inwards. Inhabits the groves and woods
both of America and Europe. Two hundred and three species.
Helix vesicalis.
H. gigantea.
H. polyzonalis.
H. monozonalis.
H. pulla.
H. lineolata.
H. mutata.
H. pomatia.
H. aspersa.
H. vermiculata.
H. Alonensis.
H. vesicolor.
H. naticoides.
H. picta.
H. galactites.
H. cepa.
H. heteroclites.
H. discolor.
H. lactea.
H. zonaria.
H. guttata.
H. Madagascarensis.
H. Javanica.
H. Peruviana.
H. simplex.
H. cidaris.
H. citrina.
H. algira.
H. verticellus.
H. olivetorum.
H. hæmastoma.
H. melanotragus.
H. extensa.
H. lucana.
H. globulus.
H. melanostoma.
H. cœlatura.
H. microstoma.
H. maculsa.
H. Richardi.
H. Bonplandii.
H. planulata.
H. labrella.
H. unguina.
H. pellis-serpentis.
H. senegalensis.
H. unidentata.
H. fructicum.
H. neglecta.
H. crespitum.
H. ericetorum.
H. intersecta.
H. Carthusianella.
H. diaphana.
H. concolor.
H. velutina.
H. obvuluta.
H. Cookiana.
H. pileus.
H. papilla.
H. punctifera.
H. plicatula.
H. planorbella.
H. scabra.
H. cariosa.
H. crenulata.
H. planorbula.
H. macularia.
H. planospira.
H. Barbadensis.
H. sinuata.
H. hippocastanum.
H. bidentalis.
H. argilacea.
H. vittata.
H. arbustorum.
H. candidissima.
H. memoralis.
H. Hortensis.
H. sylvatica.
H. pisana.
H. splendida.
H. serpentina.
H. niciensis.
H. variabilis.
H. auriculata.
H. turgidula.
H. helicella.
H. zonula.
H. tridentata.
H. septemvalva.
H. monodan.
H. fraterna.
H. coniformis.
H. concamerata.
H. nigrescens.
H. Tripolitana.
H. Sayii.
H. globulosa.
H. Caffra.
H. conformis.
H. prunum.
H. Pouzolzii.
H. contusa.
H. bicarinata.
H. vitrinoides.
H. maritima.
H. strigata.
H. muralis.
H. rugosa.
H. cornea.
H. liquifera.
H. incarnata.
H. cinctella.
H. cellaria.
H. Gaymardii.
H. nitidia.
H. plebuim.
H. personata.
H. hispidia.
H. rotundata.
H. apicina.
H. striata.
H. conspurcata.
H. conica.
H. conoidea.
H. pulchella.
H. formosa.
H. orbiculata.
H. squamosa.
H. tectiformis.
H. Madeirensis.
H. unbeculata.
H. deformis.
H. Nicæensis.
H. meridionalis.
H. melitensis.
H. circumornata.
H. gronosa.
H. Lima.
H. dentiens.
H. parilis.
H. imperator.
H. zodiaca.
H. concisa.
H. pellicuta.
H. strobilus.
H. alanda.
H. carina.
H. Bulverii.
H. pileolus.
H. vipartita.
H. sinistrorsa.
H. fibula.
H. supplicata.
H. Porto-santara.
H. punctulata.
H. exalbida.
· · · · ·
H. Mitchelliana.*
H. Vancouverensis.*
H. Caroliniensis.*
H. Nuttaliana.*
H. Columbiana.*
H. hirsuta.*
H. perspectiva.*
H. lineata.*
H. multilineata.*
H. appressa.*
H. palliata.*
H. Californiensis.*
H. Townsendiana.*
H. Nichliniana.*
H. Oregonensis.*
H. magnifica.*
H. profunda.*
H. albolabris.*
H. alternata.*
H. irrorata.*
H. inorata.*
H. indentata.*
H. inflecta.*
H. clausa.*
H. obstricta.*
H. elevata.*
H. interna.*
H. chersina.*
H. gularis.*
H. ligera.*
H. solitaria.*
H. jejuna.*
H. concava.*
H. fallax.*
H. egena.*
H. arboreus.*
H. glaphyra.*
H. Thyroides.*
H. labyrinthica.*
H. major.*
H. Pennsylvanica.*
H. subglobosa.*
H. Zaleta*
H. dentifera.*
H. delabata.*
2. Genus _Carocolla_. Pl. X.
The _Animal_ of this and the following genera of this family are
precisely the same as in Helix.
_Shell._ Orbicular, more or less convex or conoidal above; the
circumference or periphery angulated or keeled; aperture transverse,
contiguous to the axis of the shell; the right margin or lip subangular,
often toothed or plaited beneath. Inhabits dry situations in Europe and
America. Twenty-two species.
Carocolla acutistima.
C. albilabris.
C. angistoma.
C. labyrinthus.
C. lucerna.
C. inflata.
C. hispidula.
C. Gaulteriana.
C. albella.
C. bicolor.
C. Mauritiana.
C. Madagascarensis.
C. marginata.
C. lychnuchus.
C. planata.
C. planaria.
C. lapicida.
C. elegans.
· · · · ·
C. Hydiana.*
C. helicoides* (new species) _Lea_.
C. grata.*
C. Spinosa* (new species) _Lea_.
3. Genus _Achatina_. Pl. X.
_Animal._ See Helix.
_Shell._ Variable in form, but generally subturriculated, oval or
oblong, aperture entire, the right lip sharp, never reflected, columella
smooth, of which the anterior extremity is always open and truncated.
Inhabits South America. Twenty-four species.
Achatina perdix.
A. immaculata.
A. acuta.
A. Mauritania.
A. ustulata.
A. virginea.
A. Marminii.
A. fusco-lineata.
A. columnaria.
A. acicula.
A. zebra.
A. purpurea.
A. bicarinata.
A. castanea.
A. vexillum.
A. Priamus.
A. Peruviana.
A. albo-lineata.
A. fulminea.
A. folliculus.
A. oleacea.
· · · · ·
A. glans.*
A. Vanuxemensis.*
A. solida.*
4. Genus _Anostoma_. Pl. X.
_Animal._ See Helix.
_Shell._ Somewhat extraordinary in its formation, orbicular, the spire
convex and obtuse, aperture round, dentated grinning, turned upwards to
the side of the spire, margin of the lip reflected. Lakes in America and
the Sandwich Islands. Three species.
Anostoma dentata.
Anostoma depressa.
· · · · ·
A. globosa.*
5. Genus _Helicina_. Pl. X.
_Animal._ See Helix.
_Shell._ Terrestrial, distinguished only from the Helix by its columella
being transverse callous; much depressed and diminished in thickness at
the lower part, subliglobular, imperforate; aperture entire, demioval,
margin acute, forming an angle at the lower base of the right lip;
operculum corneous. Inhabits groves in Europe. Nineteen species.
Helicina neritella.
H. rhodostoma.
H. striata.
H. fasciata.
H. virida.
H. pulchella.
H. substriata.
H. Braziliensis.
H. costata.
H. aurantia.
H. major.
H. minima.
H. submarginata.
H. unifasciata.
H. Brownii.
H. depressa.
H. aureola.
H. orbiculata.
H. Tankervillii.
6. Genus _Pupa_. Pl. X.
_Animal._ See Helix.
_Shell._ Cylindrical, generally thick; aperture irregular, semi-ovate,
rounded, and subangulated beneath; margins of outer lip nearly equal and
reflected outwardly, unconnected at their upper parts; the plait of the
columella interposed between them. Most frequently found in moss in
Europe and America. Forty species.
Pupa numia.
P. uva.
P. sulcata.
P. candida.
P. labrossa.
P. fusus.
P. tridentata.
P. fasciolata.
P. zebra.
P. unicarinata.
P. maculosa.
P. clavulata.
P. ovularis.
P. Germanica.
P. cinerea.
P. tridens.
P. quadridens.
P. polyodon.
P. variabilis.
P. frumentum.
P. secale.
P. avena.
P. granum.
P. fragilis.
P. dolium.
P. umbilicata.
P. muscorum.
P. angilicus.
P. rufescens.
P. edontulis.
P. odontostoma.
P. petiveriana.
P. dentata.
· · · · ·
P. contracta.*
P. rupicola.*
P. exigua.*
P. armifera.*
P. fallax.*
P. ovata*
P. pentadon.*
7. Genus _Clausilia_. Pl. X.
_Animal._ See Helix.
_Shell._ Cylindrical, generally fusiform; summit obtuse, the last whorl
smaller than the preceding; aperture irregular, rounded, oval; margin
united, and externally reflected. Inhabits dry situations both in Europe
and America. Fifteen species.
Clausilia torticollis.
C. truncatula.
C. retusa.
C. costulata.
C. corrugata.
C. inflata.
C. Mediterranea.
C. denticulata.
C. collaris.
C. papillaris.
C. plicatula.
C. rugosa.
C. gracilis.
C. chrysalis.
· · · · ·
C. teres.*
8. Genus _Bulimus_. Pl. X.
_Animals_ of this genus in formation are precisely as the Helix; they
are, however, oviparous, producing eggs with the shell containing the
animal perfectly matured; they are frequently as large as a pigeon’s
egg.
_Shell._ Oval, sometimes turriculated, oblong; the summit of the spire
obtuse, and the last whorl larger than all the others together; aperture
oblong, oval, edge disunited; in adults the lip much reflected;
columella smooth, with an inflection in the middle, the base entire, not
channeled. Inhabits mountainous situations in Europe and America; some
beautiful specimens have been found in the woods of Ohio. Sixty-three
species.
Bulimus ovatus.
B. hæmastomus.
B. gallina.
B. sultana.
B. zigzag.
B. multifasciatus.
B. Bengalensis.
B. Caribæorum.
B. octonus.
B. terebraster.
B. undatus.
B. Richii.
B. inversus.
B. citrinus.
B. sultanus.
B. Pythogaster.
B. ovoideus.
B. interruptus.
B. Peruvianus.
B. Favannii.
B. Kambeul.
B. papyraceus.
B. calcareus.
B. decollatus.
B. Lyonetianus.
B. inflatus.
B. radiatus.
B. fragilis.
B. Guadalupensis.
B. Mexicanus.
B. articulatus.
B. acutus.
B. scobinatus.
B. planidens.
B. ventricosus.
B. montanus.
B. hordaceus.
B. lubricus.
B. iostoma.
B. geniostoma.
B. odontostoma.
B. formosus.
B. Listeri.
B. Kingii.
B. Dufresnii.
B. pulcher.
B. maugeri.
B. lævis.
B. auris leporis.
B. vexillum.
· · · · ·
B. glandiformis.*
B. parvus.*
B. virgo.*
B. gracilis.*
B. Gibbonius.*
B. multilatus.*
B. maculatus.*
B. Pealianus.*
B. lacteus.*
B. decoratus.*
B. Columbianus.*
B. multilineatus.*
B. corneus.*
9. Genus _Succinea_. Pl. X.
_Animal._ See Helix.
_Shell._ Terrestrial, very thin, pellucid, ovate oblong, with a conical,
pointed spire, formed of only one or two whorls; aperture very large and
oval, edges disunited; right edge always acute, the left arched, formed
by a smooth attenuated columella. The shells of this genus never having
their lip thickened or reflected, distinguish them from those of the
genus Bulimus, to which they bear a strong resemblance. Inhabits the
sides of ditches and lakes, both in Europe and America. Seven species.
Succinea cuculata.
S. amphibia.
S. rubescens.
S. oblonga.
S. patula.
S. pellucida.
· · · · ·
S. aperta.*
10. Genus _Auricula_. Pl. X.
_Animal._ See Helix.
_Shell._ Solid, thick, and smooth, oval, oblong spire very obtuse,
aperture entire, enlarged, ear-shaped, much contracted behind; edges not
united, right lip thick and generally reflected outwardly; the left or
columella with one or more teeth or callous plaits. This genus derives
its name from its resemblance to the ears of certain animals. It is a
land shell found chiefly in the East and West India Islands. Sixteen
species.
Auricula Midæ.
A. Judæ.
A. sileni.
A. leporis.
A. felis.
A. Dombeiana.
A. nitens.
A. angiostoma.
A. scarabæus.
A. bovina.
A. caprella.
A. myosotis.
A. minima.
A. coniformis.
A. monill.
A. labrella.
11. Genus _Cyclostoma_. Pl. X.
_Animal._ See Helix.
_Shell._ Terrestrial, distinguished from the preceding genera by a
perfectly round aperture, reflected lip, and horny operculum, summit
papillose; left edge having its origin very detached from the spire.
Inhabits the East Indies. A few species are found in America.
Thirty-eight species.
Cyclostoma planorbula.
C. volvulus.
C. carinata.
C. sulcata.
C. unicarinata.
C. rugosa.
C. labeo.
C. interrupta.
C. ambigua.
C. semilabris.
C. tricarinata.
C. obsoleta.
C. patulum.
C. truncatum,
C. pulchrum.
C. Jamaicense.
C. lineolata.
C. elongatum.
C. mirabile.
C. orbella.
C. aurantium.
C. flavula.
C. fasciata.
C. mumia.
C. quarternata.
C. ferruginea.
C. decussata.
C. mammillaris.
C. maculatum.
C. ligata.
C. elegans.
C. tortum.
C. mirabile.
· · · · ·
C. maculata.*
C. Popayana.*
C. lapidaria.*
C. marginata.*
C. dentata.*
FAMILY VIII.
LYMNACEA. Three genera.
1. Genus _Lymnea_. Pl. X.
_Animal._ See Helix.
_Shell._ Aquatic, oval, sometimes turreted; spire produced, thin,
smooth, edges disunited, the left with a very oblique plait rising on
the columella, forming an oval aperture, destitute of an operculum.
Inhabits the ponds of America and Europe. Thirty-three species.
Lymnea columnaris.
L. stagnelis.
L. palustris.
L. auricularia.
L. ovata.
L. minuta.
L. luteola.
L. acuminata.
L. intermedia.
L. leucostoma.
L. peregra.
· · · · ·
L. rubiginosus.*
L. solida.*
L. Virginiana.*
L. Emmoniensis.*
L. lessoni.*
L. apacina.*
L. catascopium.*
L. columella.*
L. elongatus.*
L. reflexus.*
L. appressus.*
L. elodes.*
L. limosa.*
L. lapidaria.*
L. dissimilis.*
L. ponderosa.*
L. integra.*
L. porata.*
L. lustrica.*
L. grana.*
L. subglobosa.*
2. Genus _Physa_. Pl. X.
_Animal._ See Helix.
_Shell._ General sinistral, oval, oblong, or globular, very smooth,
spire prominent, aperture oval, contracted posteriorly, right edge
sharp, columella twisting obliquely, and enlarging to join itself to the
anterior part of the margin, the whorls turning to the left hand gives
this shell the appellation of heterostrophe. Inhabits the ditches of
America and Europe. Ten species.
Physa fontinalis.
P. hypnorum.
P. subopaca.
· · · · ·
P. castanea.*
P. decisa.*
P. elongata.*
P. aurea.*
P. gyrina.*
P. heterostropha.*
P. ancillaria.*
3. Genus _Planorbis_. Pl. X.
_Animal._ See Helix.
_Shell._ Discoid, spire depressed, or involuted almost in the same
vertical plane, causing the shell to be depressed on each side, aperture
oblong, luniform, axis remote, margin not reflected; no operculum.
Inhabits the lakes of America and Europe. Twenty-two species.
Planorbis cornu-arietis.
P. corneus.
P. spirorbis.
P. hispidus.
P. orientalis.
P. carinatus.
P. lutescens.
P. nitidus.
P. angulatus.
P. deformis.
P. imbricatus.
P. contortus.
P. vortex.
· · · · ·
P. lens.*
P. glabratus.*
P. armigerus.*
P. parallellus.*
P. exacuous.*
P. campanulatus.*
P. trivolvis.*
P. bicarinatus.*
P. parvus.*
FAMILY IX.
MELANIANA. Three genera.
1. Genus _Melania_. Pl. X.
_Animal._ See Helix.
_Shell._ Turreted; aperture entire, spire slightly pointed, margin of
the whorls often surmounted by spires, columella smooth and arched,
closed by a thin horn-like operculum; this is a fluviatile shell, often
covered by a thick epidermis. Inhabits the rivers of India. Many fine
species are found in America. Fifty-four species.
Melania inquinata.
M. asperata.
M. spinolusa.
M. gronifera.
M. aurita.
M. lineolata.
M. trunculata.
M. carinefera.
M. truncata.
M. coarctata.
M. punctata.
M. subulata.
M. Helvetica.
M. lineata.
M. Byronensis.
M. sulcata.
M. lævigata.
M. clavis.
M. decollata.
M. amarula.
M. thiarella.
M. fasciolata.
M. lævissima.
M. corrugata.
· · · · ·
M. Troostiana.*
M. plicifera.*
M. Sayii.*
M. elevata.*
M. armigera.*
M. multilineata.*
M. proxima.*
M. Hydeii.*
M. salebrosa.*
M. bitaeniata.*
M. lema.*
M. nassula.*
M. trochiformis.*
M. elevata.*
M. laqueata.*
M. semicarinata.*
M. subularis* (_Lea_).
M. acuta.* „
M. plicata.*
M. inflata.*
N. conica.*
M. catenaria.*
M. simplex.*
M. excurta.*
M. annulifera.*
M. pyrenella.*
M. coma.*
M. alveare.*
M. cylindracea.*
M. vestita.*
M. caniculata.*
M. Virginica.*
M. tuberculata* (_Lea_).
M. elongata.* „
2. Genus _Pirena_. Pl. X.
_Animal._ Much elongated, mantle prolonged into a canal at the left
side, but without distinct tube; foot short, oval, with an anterior
marginal furrow; head terminated by a depressed proboscidiform muzzle;
tentacula very distant, thickly annulated, dilated in the inferior half
of their length, and having the eyes at the summit of this dilation;
mouth a terminal and vertical slit, without labial tooth, and with a
very small tongue; a single long and narrow branchia.
_Shell._ Distinguished from the preceding genus by having a sinus at the
base, and another at the summit; turreted; aperture longitudinal, right
lip sharp, base of the columella inclined to the right. Inhabits the
rivers of India and Africa. One species is found in America. Six
species.
Pirena terebralis.
P. cancellata.
P. aurita.
P. spinosa.
P. granulosa.
· · · · ·
P. scalariformis.*
3. Genus _Melanopsis_. Pl. X.
_Animal._ As preceding genus.
_Shell._ The Melanopsis is distinguished from the Melanaia, by the
columella being callous in the upper part, and the base truncated as in
the Achatina, and differs from the Pirena in having only a sinus or
widened opening at the base of the shell; aperture covered by a horny
operculum. Inhabits the rivers of the Archipelago. Three species.
Melanopsis costata.
M. lævigata.
M. prærosa.
FAMILY X.
PERISTOMIANA. Three genera.
1. Genus _Valvata_. Pl. X.
_Animal._ See Helix.
_Shell._ Found only in fresh water; subdiscoid or conoid, umbilicated,
spiral, whorls, rounded; angular at the summit; aperture round, not
modified by the penultimate whorl; the margins sharp and united;
operculum orbicular and horny. Inhabits the rivers of Europe and
America. Three species.
Valvata piscinalis.
· · · · ·
V. arcnifera.* (_Lea_.)
V. tricarinata.*
2. Genus _Paludina_. Pl. X.
_Animal._ See Helix.
_Shell._ Generally found in fresh water, though some species have been
found where it is salt; conoid covered with a greenish epidermis; the
whorls rounded or convex, spiral cavity modified by the last whorl;
aperture rounded, oval, oblong, angular at the summit; margins united,
acute, never reflected outwards; operculum orbicular and horny. Inhabits
the rivers of America and Europe. Thirty-one species.