"A general name on the Pacific coast of the United States for marine shells of the family <em>Haliotid&aelig; </em>(which see), having an oval form with a very wide aperture, a narrow, flattened ledge or columella, and a subspiral row of perforations extending from the apex to the distal margin of the shell."&mdash;Wright, 1902

Abalone

"A general name on the Pacific coast of the United States for marine shells of the family Haliotidæ

"A genus of bivalve mollusks, of the family Uniond&aelig;, found in the rivers of Africa and Madagascar."-Whitney, 1902

Aetheria semilunata

"A genus of bivalve mollusks, of the family Uniondæ, found in the rivers of Africa and Madagascar."-Whitney,…

Helix desertorum is a species of African snail in the class Gastropoda

African Snail

Helix desertorum is a species of African snail in the class Gastropoda

"Ammonite is the name for a large genus of fossil chambered shells."&mdash;(Charles Leonard-Stuart, 1911)

Ammonite

"Ammonite is the name for a large genus of fossil chambered shells."—(Charles Leonard-Stuart,…

"Ammonite is the name for a large genus of fossil chambered shells."&mdash;(Charles Leonard-Stuart, 1911)

Ammonite

"Ammonite is the name for a large genus of fossil chambered shells."—(Charles Leonard-Stuart,…

a fossil cephalopod similar to the nautilisk.

Ammonite

a fossil cephalopod similar to the nautilisk.

a fossil cephalopod similar to the nautilisk.

Ammonite

a fossil cephalopod similar to the nautilisk.

a fossil cephalopod similar to the nautilisk.

Ammonite

a fossil cephalopod similar to the nautilisk.

Ammonite, side view. Where the shell has been partly worn away near the aperture, the complex "suture line" is shown.

Ammonite

Ammonite, side view. Where the shell has been partly worn away near the aperture, the complex "suture…

"Goniatites henslowi. GONIOTITES. A genus of fossil ammonites, giving name to the family Goniatitidae, having a discoid shell with angulated lobed sutures." -Whitney, 1911

Ammonoid

"Goniatites henslowi. GONIOTITES. A genus of fossil ammonites, giving name to the family Goniatitidae,…

"Male of Argonauta showing "hectocotylus" arm." -Thomson, 1916

Argonauta

"Male of Argonauta showing "hectocotylus" arm." -Thomson, 1916

Auditory and equilibrative organs of mollusks.

Auditory Organs of Mollusks

Auditory and equilibrative organs of mollusks.

"Liassic 'Thunder bolt' (Belemnites hastata)." -Taylor, 1904

Belemnite

"Liassic 'Thunder bolt' (Belemnites hastata)." -Taylor, 1904

"Belemnite (restored)." -Taylor, 1904

Belemnite

"Belemnite (restored)." -Taylor, 1904

"Oolitic 'Thunder-bolt' (Belemnites abbreviatus)." -Taylor, 1904

Belemnites abbreviatus

"Oolitic 'Thunder-bolt' (Belemnites abbreviatus)." -Taylor, 1904

"Natural flint cast of phragmocone of...Belemnites mucronatus." -Taylor, 1904

Belemnites Fossil

"Natural flint cast of phragmocone of...Belemnites mucronatus." -Taylor, 1904

"Belemnites mucronatus." -Taylor, 1904

Belemnites mucronatus

"Belemnites mucronatus." -Taylor, 1904

"Oolitic 'Thunder-bolt' (Belemnites puzosianus)." -Taylor, 1904

Belemnites puzosianus

"Oolitic 'Thunder-bolt' (Belemnites puzosianus)." -Taylor, 1904

"Bivalves are those mollusks whose coverings consist of two concave shelly plates or valves united by a hinge."&mdash;(Charles Leonard-Stuart, 1911)

Bivalve

"Bivalves are those mollusks whose coverings consist of two concave shelly plates or valves united by…

"Shell of a Bivalve Mollusk, inner surface. ad.a., depression showing the attachment of the anterior adductor muscle; ad.p., posterior adductor muscle; h, hinge with teeth; l, attachments of the ligaments; p, pallial line, marking the attachment of the mantle muscles; s, the pallial sinus, marking the attachment of the retractor muscles of the siphon; u, umbo or beak." &mdash; Galloway

Bivalve Mollusk

"Shell of a Bivalve Mollusk, inner surface. ad.a., depression showing the attachment of the anterior…

"Interior of Brachiopod shell, showing calcareous support for the 'arms'" -Thomson, 1916

Brachiopod

"Interior of Brachiopod shell, showing calcareous support for the 'arms'" -Thomson, 1916

The shell of Athyris concentrica, a species of brachiopod.

Athyris Brachiopod

The shell of Athyris concentrica, a species of brachiopod.

The dorsal valve of the brachiopod Atrypa reticularis.

Atrypa Brachiopod

The dorsal valve of the brachiopod Atrypa reticularis.

The shell of Atrypa reticularis, a species of brachiopod.

Atrypa Brachiopod

The shell of Atrypa reticularis, a species of brachiopod.

The shell of Spirifer striatus, a species of brachiopod.

Spirifer Brachiopod

The shell of Spirifer striatus, a species of brachiopod.

Interior of the dorsal valve of Spirifer striatus.

Spirifer Brachiopod

Interior of the dorsal valve of Spirifer striatus.

The interior view of the brachiopod Waldheimia flavescens.

Waldheimia Brachiopod

The interior view of the brachiopod Waldheimia flavescens.

The cephalopods are the mollusk class Cephalopoda characterized by bilateral body symmetry, a prominent head, and a modification of the mollusk foot, a muscular hydrostat, into the form of arms or tentacles. Teuthology, a branch of malacology, is the study of cephalopods. The class contains two extant subclasses. In the Coleoidea, the mollusk shell has been internalized or is absent; this subclass includes the octopuses, squid, and cuttlefish. In the Nautiloidea the shell remains; this subclass includes the nautilus. About 786 distinct living species of cephalopods have been identified. Two important extinct taxa are Ammonoidea, the ammonites, and Belemnoidea, the belemnites Cephalopods are found in all the oceans of Earth, at all depths. None of them can tolerate freshwater, but a few species tolerate more or less brackish water.

Cephalopod

The cephalopods are the mollusk class Cephalopoda characterized by bilateral body symmetry, a prominent…

A simple straight-shelled cephalopod. Where the shell has been removed, the straight sutures are shown.

Cephalopod

A simple straight-shelled cephalopod. Where the shell has been removed, the straight sutures are shown.

"Cephalopoda is a class of mollusks, the highest in organization of the division of the animal kingdom. To this class belong the Nautili, Squids, Cuttle-fish, etc. The Cephalopoda receive their name from having organs of prehension and locomotion attached to the head, an arrangement toward which a gradual approach may be traced in the highest gasteropod mollusks."&mdash;(Charles Leonard-Stuart, 1911)

Cephalopoda

"Cephalopoda is a class of mollusks, the highest in organization of the division of the animal kingdom.…

A dorsal view of a chiton, showing the eight shell plates. Chitons are small to large, primitive marine mollusks in the class Polyplacophora. There are 900 to 1,000 extant species of chitons in the class, which was formerly known as Amphineura. Chitons have a shell which is composed of eight separate shell plates or valves. These plates overlap somewhat at the front and back edges, and yet the plates articulate well with one another. Because of this, although the plates provide good protection for impacts from above, they nonetheless permit the chiton to flex upward when needed for locomotion over uneven surfaces, and also the animal can slowly curl up into a ball when it is dislodged from the underlying surface. The shell plates are surrounded by a structure known as a girdle.

Chiton (Dorsal)

A dorsal view of a chiton, showing the eight shell plates. Chitons are small to large, primitive marine…

A ventral view of a chiton, showing p, foot; o, mouth; kr, oval fringe; and br, the numerous ctenidia. Chitons are small to large, primitive marine mollusks in the class Polyplacophora. There are 900 to 1,000 extant species of chitons in the class, which was formerly known as Amphineura. Chitons have a shell which is composed of eight separate shell plates or valves. These plates overlap somewhat at the front and back edges, and yet the plates articulate well with one another. Because of this, although the plates provide good protection for impacts from above, they nonetheless permit the chiton to flex upward when needed for locomotion over uneven surfaces, and also the animal can slowly curl up into a ball when it is dislodged from the underlying surface. The shell plates are surrounded by a structure known as a girdle.

Chiton (Ventral)

A ventral view of a chiton, showing p, foot; o, mouth; kr, oval fringe; and br, the numerous ctenidia.…

An illustration of the dorsal view of a chiton with the shell removed. Showing b, buccal mass; ov, ovary; od, oviduct; i, coils of intestine; ao, aorta; c' keft testine; and c, ventricle.

Chiton with Shell Removed

An illustration of the dorsal view of a chiton with the shell removed. Showing b, buccal mass; ov, ovary;…

A characteristic fusoid gastropod of the northern Atlantic.

Chrysodomus Decemcostatus

A characteristic fusoid gastropod of the northern Atlantic.

a - foot; b,c - siphons

Clam

a - foot; b,c - siphons

"Mya arenaria, a burrowing clam. The siphon is represented as fully extended. This is quickly retracted when the animal is disturbed." -Galloway, 1915

Burrowing Clam

"Mya arenaria, a burrowing clam. The siphon is represented as fully extended. This is quickly retracted…

"a, a', impressions of the muscles; p, pallial line; s, bend occupied by the siphon; h, hinge; c, t, t', teeth." -Cooper, 1887

Clamshell

"a, a', impressions of the muscles; p, pallial line; s, bend occupied by the siphon; h, hinge; c, t,…

The scorpion shell (Pteroceras lambis) is a large sea snail in the Strombidae family of conchs.

Scorpion Conch

The scorpion shell (Pteroceras lambis) is a large sea snail in the Strombidae family of conchs.

The side view of Sepia officinalis, or the common cuttlefish.

Cuttlefish

The side view of Sepia officinalis, or the common cuttlefish.

"Diagram of circulatory and excretory systems in a Decapod-like Sepia. 1, Gill; 2, renal sac; 3, afferent branchial vessel; 4, branchial heart; 5, abdominal vein; 6, heart; 7, viscero-pericardial sac (body cavity); 8, genital organ; 9, posterior aorta; 10, "auricle"; 11, glandular appendix of branchial heart; 12, renal appendices of branchial vein; 13, external aperure of kidney; 14, vena cava; 15, anterior aorta; 16, bifurcation of vena cava; 17, reno-pericardial aperture." -Thomson, 1916

Cuttlefish Circulatory and Excretory Systems

"Diagram of circulatory and excretory systems in a Decapod-like Sepia. 1, Gill; 2, renal sac; 3, afferent…

"Bunch of Sepia eggs attached to plant." -Thomson, 1916

Cuttlefish Eggs

"Bunch of Sepia eggs attached to plant." -Thomson, 1916

"Diagram of the structure of Sepia. a., Eight short arms around mouth; l.a., one of the two long arms; b., beak of the mouth; c.g., cerebral ganglia, with commissures to the others; E., eye; g., gullet; d.g., digestive gland (the "salivary glands" are not represented); st., stomach; a., anus; sh., shell-sac with sepiostaire; k., kidney; R., reproductive organ; br.h., branchial heart; g., a gill; i.b., ink-bag; m.c., mantle cavity; f., funnel." -Thomson, 1916

Cuttlefish Structure

"Diagram of the structure of Sepia. a., Eight short arms around mouth; l.a., one of the two long arms;…

The Common Cuttlefish (Sepia officinalis) is a mollusc in the Sepiidae family of cephalopods.

Common Cuttlefish

The Common Cuttlefish (Sepia officinalis) is a mollusc in the Sepiidae family of cephalopods.

"Cyprea Europea." -Taylor, 1904

Cyprea Europea

"Cyprea Europea." -Taylor, 1904

"Dissection of snail. T., Short horn; TT., long horn with eye; N., cerebral ganglia; S.G., salivary glands on the crop; F., foot; M., columellar muscle; V.C., visceral coil; O.T., ovotestis; V., ventricle of heart; R. rectum; U., ureter; B.V., blood vessels returning to the auricle from the mantle; A., pulmonary aperture; MA., edge of the mantle." -Thomson, 1916

Dissection

"Dissection of snail. T., Short horn; TT., long horn with eye; N., cerebral ganglia; S.G., salivary…

"The <em>U. elongata</em> is found in Great Britain, and formerly produced numerous pearly; these were famous even in the time of Julius Caeser. In Ireland and Scotland this species has produced pearly, in modern times, valued at between twenty to four hundred dollars." &mdash; Goodrich, 1859

Unio elongata

"The U. elongata is found in Great Britain, and formerly produced numerous pearly; these were…

"Emarginula reticulata." -Taylor, 1904

Emarginula reticulata

"Emarginula reticulata." -Taylor, 1904

Section through the cup-shaped eye of a gastropod. Labels: e, epithelium covering body; cv, vitreous body; R, retina; N, nerve.

Eye of Gasteropod

Section through the cup-shaped eye of a gastropod. Labels: e, epithelium covering body; cv, vitreous…

An illustration of a pallial eye and aesthetes of a chiton.

Pallial Eye

An illustration of a pallial eye and aesthetes of a chiton.

The shell of the Fig Shell Snail (Ficula ficus), a sea snail in the Ficidae family.

Fig Shell

The shell of the Fig Shell Snail (Ficula ficus), a sea snail in the Ficidae family.

Fu'sus is a genus of gastropods, which are allied to the British whelk and American conch, and which include, in F. colosseus, perhaps the largest living gastropod. The shell is fusiform, with a many-whorled spire and a long, straight canal. One species, F. antiguus, is dredged in the seas about Great Britain to be sold in the London markets as food.

Fu'sus

Fu'sus is a genus of gastropods, which are allied to the British whelk and American conch, and which…

A characteristic gastropod of the Atlantic coast from Cape Cod to Florida.

Fulgar Carica

A characteristic gastropod of the Atlantic coast from Cape Cod to Florida.

Galatea reclusa is a species of bivalve mollusk in the Donacidae family of bean clams (wedge shells).

Right Valve of Galatea Bivalve

Galatea reclusa is a species of bivalve mollusk in the Donacidae family of bean clams (wedge shells).

"Dorsal View of Gastrochaena. The ventral view shows the dried mantle with pedal perforation." -Whitney, 1911

Dorsal View of Gastrochaena

"Dorsal View of Gastrochaena. The ventral view shows the dried mantle with pedal perforation." -Whitney,…

"Lateral View of Gastrochaena. The ventral view shows the dried mantle with pedal perforation." -Whitney, 1911

Lateral View of Gastrochaena

"Lateral View of Gastrochaena. The ventral view shows the dried mantle with pedal perforation." -Whitney,…

"Ventral View of Gastrochaena. The ventral view shows the dried mantle with pedal perforation." -Whitney, 1911

Ventral View of Gastrochaena

"Ventral View of Gastrochaena. The ventral view shows the dried mantle with pedal perforation." -Whitney,…

The shell of Anchura (Drepancheilus) Americana, a species of gastropod.

Anchura Gastropod

The shell of Anchura (Drepancheilus) Americana, a species of gastropod.

The exterior of the shell of Bulla speciosa, a species of gastropod.

Exterior of Bulla Gastropod

The exterior of the shell of Bulla speciosa, a species of gastropod.

The interior of the shell of Bulla speciosa, a species of gastropod.

Interior of Bulla Gastropod

The interior of the shell of Bulla speciosa, a species of gastropod.

The shell of Fasciolario buccinoides, a species of gastropod.

Fasciolario Gastropod

The shell of Fasciolario buccinoides, a species of gastropod.