regularly gaping at the anterior portion of the inferior edge; summits
anterior and distant; hinge buccal, longitudinal, toothless; ligament
rounded, nearly exterior, inserted in an excavation in each valve; a
central muscular impression, divided into three very distinct parts.
Inhabits the Indian, Australasian, American, and Mediterranean seas. Six
living species. Eleven fossil.
Lima inflata.
L. squamosa.
L. annulata.
L. glacialis.
L. fragilis.
L. linguatula.
3. Genus _Pecten_. Pl. IX.
_Animal._ Body more or less compressed, orbicular; mantle furnished with
a single row of tentacular papillæ, and with small oculiform,
pedunculated disks, with regular spaces between them; rudiment of a
canaliculated foot, and a byssus; mouth surrounded with fleshy
appendages, irregularly ramified.
_Shell._ Free, regular, thin, solid, equivalve, equilateral,
auriculated; summits contiguous; hinge toothless, a ligamentous membrane
throughout all its extent, besides a short, thick, ligament, almost
altogether internal, and filling a triangular excavation under the
summit; a single subcentral muscular impression. Found in almost all
seas. Sixty-two species; and, according to Defrance, ninety-eight
fossil.
Pecten maximus.
P. Jacobæus.
P. bifrons.
P. zigzag.
P. medius.
P. Latirentii.
P. pleuronectes.
P. purpuratus.
P. pallius.
P. impricatus.
P. asperimus.
P. varius.
P. glaber.
P. grisens.
P. flabellatus.
P. quadradiatus.
P. Tranquebaricus.
P. hybridus.
P. obliteratus.
P. Magellanicus.
P. lineolaris.
P. nodosus.
P. pusio.
P. gibbus.
P. ornatus.
P. florens.
P. opercularis.
P. tigris.
P. histrionicus.
P. turgidus.
P. aspersus.
P. plicus.
P. rastellus.
P. flagellatus.
P. flavidulus.
P. Japanicus.
P. radulus.
P. pes-felis.
P. sauciatus.
P. aurantius.
P. sinuosus.
P. virgo.
P. Isabella.
P. flexuosa.
P. inflexus.
P. miniaceous.
P. lividus.
P. sulcatus.
P. unicolor.
P. distans.
P. irradians.
P. dispar.
P. Islandicus.
P. sulphureus.
P. pellucidus.
P. sanguineous.
P. senatorius.
P. lunatus.
P. lineatus.
· · · · ·
P. dislocatus.*
P. concentricus.*
P. monotimeris.*
P. Latiauratus*
P. Pealii.*
4. Genus _Plagiostoma_. Pl. IX.
_Animal._ Entirely unknown.
_Shell._ Moderately thick, regular, free, subequivalve, subauriculated,
the two valves nearly equally dilated, both provided with a distinct
summit reflexed to the middle of a plane surface, with a large
triangular slope in the middle; articulation transverse, straight, and
by two distant lateral condylæ. Ten species. Fossils only.
5. Genus _Plicatula_. Pl. IX.
_Animal._ Unknown.
_Shell._ Solid, adhering, subirregular, inauriculated, inequivalve,
pointed at the summit, rounded and subplicated posteriorly; inferior
valve without heel; hinge cephalic, longitudinal, provided upon each
valve with two strong teeth, entering in corresponding cavities;
ligament altogether internal and inserted in a median cavity. Inhabits
the American seas. Five species.
Plicatula ramosa.
P. depressa.
P. cristata.
P. Australis.
P. reniformis.
6. Genus _Spondylus_. Pl. IX.
_Animal._ Body moderately compressed, provided inferiorly with a
rudiment of a foot, without byssus; mantle open in all its inferior and
superior portion; mouth surrounded with very thick and fringed lips.
_Shell._ Solid, adhering, subregular, more or less spined,
subauriculated, inequivalve; the right or inferior valve fixed, much
more excavated than the other, and having posteriorly at the summit a
triangular face enlarging, and elongating with age; hinge longitudinal,
provided in each valve with two strong teeth entering corresponding
cavities; ligament short, nearly median, partly exterior; muscular
impression single and subdorsal. Found in all the seas of hot climates,
and even in the Mediterranean. Four or five fossils are found in France,
one in South America. Twenty-one species.
Spondylus candidus.
S. coccineus.
S. spathuliferus.
S. gædaropus.
S. arachnoides.
S. multilamellatus.
S. longitudinalis.
S. costatus.
S. longispinous.
S. regius.
S. variegatus.
S. avicularis.
S. zonalis.
S. crassisquama.
S. ducalis.
S. violascens.
S. microlepos.
S. crocens.
S. radians.
S. aurantius.
· · · · ·
S. Americanus.*
7. Genus _Podopsis_. Pl. IX.
_Animal._ Unknown.
_Shell._ Subregular, somewhat thick, equilateral, symmetrical,
inequivalve, adhering by the extremity of the shorter valve; the other
terminating in a pointed, reflexed, and median summit. Two fossil
species.
FAMILY XIX.
OSTRACEA. Six genera.
1. Genus _Ostrea_. Pl. IX.
_Animal._ Body compressed, more or less orbicular; edges of the mantle
thick, not adhering or retractile, and provided with a double row of
short and numerous tentacular filaments; two pairs of elongated and
triangular labial appendages; a subcentral bipartite muscle.
_Shell._ Irregular, inequivalve, inequilateral, roughly foliaceous, the
left or inferior valve adhering, larger and deeper than the other, its
summit prolonged with age into a sort of heel; the right or superior
valve more or less operculiform; hinge oral, toothless; ligament
subinterior, short, inserted in an oblong cardinal cavity increasing
with the summit; muscular impression single and subcentral. Found in all
seas near the mouths of rivers. Defrance enumerates one hundred and
twenty species. Lamarck thirty-three fossil, forty-nine living.
Ostrea edulis.
O. ruscuriana.
O. borealis.
O. cochlear.
O. gallina.
O. lingua.
O. Braziliana.
O. rostralis.
O. denticulata.
O. cornucopiæ.
O. doridella.
O. Limacella.
O. hippopus.
O. Adriatica.
O. cristata.
O. numisma.
O. tulipa.
O. scabra.
O. parasitica.
O. spathulata.
O. cucullata.
O. rubella.
O. erucella.
O. labrella.
O. radiata.
O. Canadensis.
O. mytiloides.
O. trapezina.
O. rufa.
O. gibbosa.
O. eliptica.
O. deformis.
O. plicatula.
O. fusca.
O. cristagalli.
O. virginica.
O. excavata.
O. simuata.
O. tuberculata.
O. Magaritacea.
O. Australis.
O. haliotidæa.
O. fucorum.
O. glaucina.
O. turbinata.
O. folia.
O. hyotis.
O. imbricata.
· · · · ·
O. semicylindrica.*
2. Genus _Gryphæa_. Pl. IX.
_Animal._ Unknown.
_Shell._ More finely lamellated than in the _Ostrea_, free, or slightly
adhering, subequilateral, very inequivalve; the inferior valve very
concave, with a summit more or less recurved in a hook; the superior
opiculiform and much smaller; hinge toothless; ligament inserted in an
elongated and arcuated cavity; a single muscular impression. Habitation
unknown. One species.
Gryphæa augulata.
3. Genus _Vulsella_. Pl. IX.
_Animal._ Body elongated and compressed; mantle much prolonged
posteriorly, and edged with two rows of very close tubercular papillæ; a
moderately large abdominal foot, proboscidiform, canaliculated, without
byssus; a very large transversal mouth with well-developed triangular
labial appendages; branchiæ narrow, very long, and united in nearly all
their extent.
_Shell._ Subnacred, irregular, flat, elongated, subequivalve,
inequilateral, with summits anterior, distant and flexed inferiorly;
hinge oral and toothless; ligament undivided, thick, inserted in a round
pit excavated in a projecting apophysis upon each valve; a moderately
large subcentral muscular impression, and two very small ones altogether
anterior. Inhabits the Indian and Australasian seas. Six living species.
One fossil.
Vulsella hians.
V. rugosa.
V. spongiarum.
V. lingulata.
V. mytilina.
V. ævata.
4. Genus _Placuna_. Pl. IX.
_Animal._ Entirely unknown.
_Shell._ Free, subirregular, very fine, almost entirely translucid,
flat, subequivalve, subequilateral, slightly auriculated; hinge
altogether internal, formed upon the superior valve, which is the
smaller, by two elongated, unequal, oblique, crests; converging to the
summit, at the internal side of which a ligament is attached in the form
of a V, a single, small, subcentral muscular impression. Inhabits the
Indian seas. Two fossils in France. Three living species.
Placuna sella.
P. papyracea.
P. placenta.
5. Genus _Anomia_. Pl. IX.
_Animal._ Much compressed; edges of the mantle very fine; not adhering,
and furnished exteriorly with a row of tentacular filaments; contractile
muscle thick, divided into three parts, the largest of which passes
partially across a slope of the inferior valve, and often contains a
calcareous substance or small bone, adhering to marine bodies.
_Shell._ Adhering, irregular, inequivalve, inequilateral, ostraceous;
inferior valve a little flatter than the superior, divided at the summit
into two sloping branches, whose approximation forms a large oval hole;
the superior valve, which is the larger, has an oval excavation under
the summit; a subcentral muscular impression, divided into three parts.
Inhabits the British coasts. Two beautiful species are found on the
shores of Rhode Island and New Jersey. Nine species.
Anomia patellaris.
A. pyriformis.
A. lens.
A. cepa.
A. electrica.
A. membranacea.
A. squamula.
· · · · ·
A. ephippium.*
A. fornicata.*
6. Genus _Crania_. Pl. IX.
_Animal._ See Anomia.
_Shell._ Orbicular, the upper valve gibbous and conical; lower valve,
flat, with three perforations. Inhabits the Indian Ocean. One species.
Crania orbicula.
FAMILY XX.
BRACHIOPODA. Three genera.
1. Genus _Orbicula_. Pl. IX.
_Animal._ Body much compressed and rounded; mantle open throughout its
whole circumference; two ciliated tentacular appendages.
_Shell._ Orbicular, much compressed, inequilateral, very inequivalve;
inferior valve very thin, adhering, imperforated, the superior
patelloid, with the summit more or less inclined towards the posterior
side. Inhabits the Norwegian seas. One living species. Two fossil.
Orbicula Norwegica.
2. Genus _Terebratula_. Pl. IX.
_Animal._ Depressed, circular or oval, more or less elongated, with two,
long, pectinated, labial tentacula.
_Shell._ Thin, inequivalve, regular, subtrigonal; one of the valves
larger and more dilated than the other, which is sometimes operculiform;
hinge condyloid, in a straight line, and formed by two oblique articular
surfaces in one valve placed between corresponding projections in the
other. Inhabits the sea at the Zetland Islands. Two species are found in
America. Thirteen living species. Thirty-eight fossil.
Terebratula dilatata.
T. flavescens.
T. dorsata.
T. Vitrea.
T. dentata.
T. globosa.
T. caput-serpentis.
T. psittacea.
T. rotunda.
T. pisa.
T. sanguinea.
· · · · ·
T. septentrionalis.*
T. truncata.*
3. Genus _Lingula_. Pl. IX.
_Animal._ Depressed, oval, somewhat elongated, inclosed between two
lobes of a mantle, slit throughout its anterior half, and having
pectinated branchiæ adhering to the internal surface; mouth simple,
having on each side a long tentacular appendage ciliated in all its
external edge, and rolling itself up spirally in the shell.
_Shell._ With an epidermis, subequivalve, equilateral, depressed,
elongated, truncated anteriorly; the summit median and posterior; no
trace of ligament; a long fibro-gelatinous peduncle fixing the shell
vertically to submarine bodies; muscular impression multiple. Inhabits
the Indian Ocean. One species.
Lingula anatina.
CLASS IV.
MOLLUSCA.
Animals soft, inarticulated, furnished with an anterior head, projecting
or salient; most frequently with eyes and tentaculæ, or possessing, at
their summit, arms disposed in the form of a coronet: their mouth either
short, elongated, or tubular, exsertile, and generally armed with hard
parts. Mantle diversified, having its edges free on the sides of the
body, or the lobes united, forming a sack, which in part envelopes the
animal; gills or respiratory organs various, circulation double, one
particular, the other general; heart unilocular, sometimes with the
auricles divided, and very distant; no medullary cord along the body,
but scattered nerves and ganglions. Twenty-two families.
FAMILY I.
PTEROPODA. Six genera.
Some genera of this family are without a testaceous covering, mentioned
only to preserve the family entire.
1. Genus _Hyalæa_. Pl. IX.
_Animal._ Body enclosed in a shell, winged before, two opposite wings,
somewhat retractile, inserted at the sides of the mouth, head distinct,
mouth terminal, placed at the junction of the fins; without eyes.
_Shell._ Symmetrical, very thin and transparent, valves unequal, flat
above, convex below, open like a cleft anteriorly, summit truncated and
tridentated posteriorly. Inhabits the Mediterranean. Two species.
Hyalæa tridentata.
H. cuspidata.
2. Genus _Clio_. Pl. IX.
_Animal._ Body free, naked, more or less elongated, tapering to the
rear, head very distinct; provided with six, long, conical, retractile
tentaculæ, separated into two groups of three each; mouth altogether
terminal and vertical, eyes sessile, rudiment of a foot under the neck.
This is a molluscous animal without any testaceous covering, but is here
placed as leading to other genera which have shells. Inhabits the Indian
seas. Two species.
Clio borealis.
C. Australis.
3. Genus _Cleodora_. Pl. IX.
_Animal._ Body oblong, gelatinous, contractile; a head in front with two
wings, and the posterior part enveloped in a shell, head distinct,
projecting and round; two eyes; mouth in the form of a small beak;
destitute of tentaculæ; two, opposite, membranaceous, pellucid, and
cordated wings, placed at the base of the neck.
_Shell._ Pyramidal, triangular, of a gelatinous or cartilaginous
substance, very thin and transparent; aperture obliquely truncated.
Inhabits the South American seas. Two species.
Cleodora pyramidata.
C. caudata.
4. Genus _Limacina_. Pl. IX.
_Animal._ Body soft, oblong, two branchial fins situated at the base of
the neck; posterior part of the body spiral, and enveloped in a shell.
_Shell._ Thin, fragile, papyraceous, spiral, the whorls reunited in a
planorbis form, and deeply and largely umbilicated on one side; aperture
large and entire. Inhabits the North seas. One species.
Limacina helicialis.
5. Genus _Cymbulia_. Pl. IX.
_Animal._ Body oblong, gelatinous, pellucid, enclosing a shell; head
sessile; two eyes, and two retractile tentacula; mouth with a retractile
proboscis; two, opposite, oblong, ovate, branched wings, connate at
their posterior base.
_Shell._ Gelatinous, cartilaginous, very transparent, crystalline,
oblong, in shape of a shoe, from which it has derived the name of the
slipper, truncated at the summit; aperture lateral and anterior.
Inhabits the Mediterranean. One species.
Cymbulia Peronii.
6. Genus _Pneumodermon_. Pl. IX.
A molluscous animal, without any testaceous covering, and much
resembling the genus Clio. Inhabits the Indian seas. One species.
Pneumodermon Peronii.
FAMILY II.
PHYLLIDIACEA. Six genera.
1. Genus _Phyllidia_. Pl. IX.
A mollusca similar to the preceding genus, without a shell, but its back
covered with a rough or coriaceous skin. Inhabits the Mediterranean.
Three species.
Phyllidia varicosa.
P. pustulosa.
P. ocellata.
2. Genus _Chitonellus_. Pl. IX.
_Animal._ Body creeping, elongated; middle of the back provided its
entire length with a detached, multivalve shell; the alternate pieces
for the most part longitudinal; sides naked; branchiæ disposed around
the body; foot cleft longitudinally by a deep furrow.
_Shell._ Each valve with striæ radiating from its apex; the margins
serrated; the base of the last valve obtuse. The testaceous plates of
this genus are never joined like those of the Chiton, so that the animal
can move in every direction. Upon the contraction of the animal after
death, however, these valves become nearly united. Inhabits the seas of
New Holland. Two species.
Chitonellus striatus.
C. larvæformis.
3. Genus _Chiton_. Pl. IX.
_Animal._ Body creeping, ovate oblong, convex, round at both
extremities; marginated with a coriaceous skin: the back covered by a
longitudinal series of testaceous, transverse, imbricated, and moveable
plates; head before, sessile, with the mouth placed below, destitute of
tentacula or eyes; branchiæ placed round the body, under the margin of
the skin; and orifice at the posterior extremity.
_Shell._ Eight imbricated valves, nearly smooth, slightly carinated, and
rounded at the margins: summit more or less marked and curved by
longitudinal elongations. Inhabits the British and American coasts.
Sixty-three species.
Chiton fulvus.
C. pisceus.
C. ruber.
C. lævis.
C. spinosus.
C. fascicularis.
C. marginatus.
C. crinitus.
C. siculus.
C. niger.
C. spiniferous.
C. coquimbensis.
C. lumingii.
C. granosus.
C. glauco-sinctus.
C. disjunctus.
C. elegans.
C. lineatus.
C. sulcatus.
C. bicolor.
C. cerasimus.
C. Magellanicus.
C. marmoratus.
C. nebulosus.
C. olivaceous.
C. latus.
C. punctatus.
C. viridus.
C. cinerus.
C. tunicatus.
C. gigas.
C. squamosus.
C. Peruvianus.
C. tesselatus.
C. capensis.
C. Carmichaelis.
C. echinatus.
C. striatus.
C. lineolatus.
C. chilensis.
C. tuberculatus.
C. hispidus.
C. thalassimus.
C. porosus.
C. larvaformis.
C. undulatus.
C. luteolus.
C. fuscus.
C. minimus.
C. cimex.
C. ascellus.
C. Icelandicus.
C. fasciatus.
C. setosus.
C. variegatus.
C. asselloides.
C. indus.
C. albas.
C. castaneus.
· · · · ·
C. Emersonii.*
C. fulminatus.*
C. amœna.*
C. alternata.*
C. sagrinatus.*
4. Genus _Patella_. Pl. IX.
_Animal._ Body completely covered by the shell; head with two acute
tentaculæ, and the eyes situated at their exterior base; branchiæ placed
under the mantle and around the body.
_Shell._ This numerous and beautiful genus of Linnæus has been
subdivided into the several distinct genera of Fissurella, Emarginula,
Navicella, Umbrella, Pileopsis, Calyptrea, Crepidula, Parmophora, and
Ancylus; each of which possesses sufficiently well-defined characters to
authorize a separation, by which they may be more easily distinguished
from the still widely extended family of Patella. Oval, conic, or a
little depressed, outside green or brown, sometimes radiated with
various colours; having divergent striæ and concentric wrinkles, inside
glossy, iridescent, with yellow or fawn-coloured, purple, blue, or brown
radiations. Inhabits almost every coast. Forty-nine species.
Patella safiana.
P. testitudinaria.
P. cochlear.
P. compressa.
P. granularis.
P. decaurata.
P. Magellanica.
P. stellifera.
P. vulgata.
P. mammillaris.
P. lineata.
P. leucopleura.
P. notata.
P. Tarentina.
P. punctata.
P. puncturata.
P. Javanica.
P. tuberculifera.
P. miniata.
P. pellucida.
P. tricostata.
P. Australis.
P. apicina.
P. granatina.
P. oculus.
P. Galathia.
P. pectinata.
P. viridula.
P. scutellar.
P. radians.
P. cærulea.
P. plumbia.
P. umbrella.
P. pyramidata.
P. luteola.
P. aspera.
P. spinifera.
P. longicosta.
P. barbata.
P. angulosa.
P. saccharina.
P. laciniosa.
P. plicata.
· · · · ·
P. amœna.*
P. alternata.*
P. alveus.*
P. candida.*
5. Genus _Umbrella_. Pl. IX.
_Animal._ Body very thick and oval, provided with a dorsal shell; foot
large, smooth, and flat, surrounded by a border, anteriorly notched,
attenuated behind; head indistinct; four tentacula, the two upper ones
thick, short, and truncated, the other two thin, and shaped like
pedunculated crests; having foliaceous branchiæ.
_Shell._ External, orbicular, subirregular, nearly flat, slightly convex
above, white, with apex near the middle; margin acute, internal surface
rather concave; having a callous disk, coloured, depressed in the
centre, surrounded by a smooth border. Inhabits the Indian Ocean. Two
species.
Umbrella Indica.
U. Mediterranea.
6. Genus _Pleurobranchus_. Pl. IX.
_Animal._ Body creeping, fleshy; mantle and foot expanded; branchiæ
placed on the right side; cloak enveloping the shell; neck short,
contracted in some species, with an emarginate front, exhibiting the
commencement of the inferior tentacula, the upper ones tubular and
cloven; gills at the edge of the dorsal plait, mouth provided with a
short, retractile proboscis.
_Shell._ Depressed, oval, oblong, concentrically wrinkled, almost
entirely open, rounded and convoluted; the vertex with a single turn.
Inhabits the coast of Devonshire in England. Two species.
Pleurobranchus Peronii.
P. Laqueare.
FAMILY III.
CALYPTRACEA. Seven genera.
1. Genus _Parmophorus_. Pl. IX.
_Animal._ Body creeping, thick, oblong-ovate, broad behind, obtuse at
the extremities; border of the mantle cleft before, and suspended
vertically around; head distinct, and slit below; two conical contracted
tentacula, at the base of which are placed the eyes, which are somewhat
pedunculated; mouth below, funnel-shaped, oblique, truncated, and
concealed; branchial cavity opening anteriorly behind the head by a
transverse fissure.
_Shell._ Oblong, very depressed, slightly convex above, obtuse at
extremities, anteriorly channeled by a slight sinus, and having towards
the posterior part a small pointed apex, inclined backwards; the lower
surface slightly concave. Inhabits the Australian seas. Four species.
One fossil.
Parmophorus Australis.
P. brevicula.
P. granulata.
P. ambigua.
2. Genus _Emarginula_. Pl. IX.
_Animal._ Body creeping, with two, conical, tentacular eyes at the
external base; mantle large, partly covering the margin of the shell;
foot very large and thick.
_Shell._ Shield-like, conical; summit inclined; the cavity simple,
having a notch or hollow cut on its posterior margin; shells of this
genus are generally very small. Inhabits the British seas. Five species.
Emarginula Blainvillii.
E. Cuvierii.
E. fissura.
E. rubra.
E. marginata.
3. Genus _Fissurella_. Pl. IX.
_Animal._ With the head truncated in front; two conical tentacula, with
eyes at their exterior base; mouth simple, terminal, and destitute of
jaws; two pectinated branchiæ projecting from the cavity; mantle large,
protruding beyond the shell.
_Shell._ Shield-shaped, conical recurved, summit entire, depressed,
concave below, perforated at the summit in the form of a key hole,
without a spire; the exterior surface ribbed longitudinally. Inhabits
the European and American seas. Twenty-two species.
Fissurella Cayennensis.
F. lilacina.
F. Javanicensis.
F. fascicularis.
F. rosea.
F. Barbadensis.
F. radiata.
F. nodosa.
F. nimbosa.
F. crassa.
F. Græca.
F. picta.
F. pustula.
F. hiantula.
F. viridula.
F. depressa.
F. Peruviana.
F. gibberula.
F. minuta.
F. plicata.
· · · · ·
F. alternata.*
F. redimicula.*
4. Genus _Pileopsis_. Pl. X.
_Animal._ With two conical tentacula, and the eyes at their base;
branchiæ formed in a row under the anterior margin of the cavity, near
the neck.
_Shell._ Obliquely conical, anteriorly recurved, apex bent, almost
spiral; aperture rounded, elliptical, the anterior margin shortest,
acute, slightly sinuated; the posterior largest and rounded. One
elongated and arched muscular impression, situated under the posterior
margin. Inhabits the seas of Europe. Nine species.
Pileopsis intorta.
P. subrufa.
P. spirirostris.
P. retortella.
P. ungarica.
P. mitula.
P. pennata.
P. squamæformis.
P. depressa.
5. Genus _Calyptrea_. Pl. X.
_Animal._ The same as preceding genus.
_Shell._ This genus derives its common name, “the Cup-and-Saucer
Limpit,” by having in the interior cavity a cup-shaped appendage, which
is sometimes vertical, and sometimes like a horse-shoe, with a muscular
impression of variable form, vertex ending in a small volution; smooth,
margin entire, very glossy within, and provided with a laminar plate.
Inhabits the Chinese and S. American seas. Nine species.
Calyptrea porcellana.
C. equestris.
C. fornicata.
C. peziza.
C. angulata.
C. tecum-sinense.
C. scutellata.
C. poculum.
· · · · ·
C. striata.*
6. Genus _Crepidula_. Pl. X.
_Animal._ Head anteriorly forked, having two conical tentacula, with the
eyes placed at their exterior base; mouth simple, destitute of jaws, and
situated in the bifurcation of the head; branchiæ with tufts and
projecting from the branchial cavity; the mantle never bordering the
shell; foot minute, orifice lateral.