Part 8

Orbicular; upper valve gibbous and conical, lower valve flat, with three perforations.

FAMILY XX. BRACHIOPODA. Three genera.

1. Orbicula. One species.

Greatly resembling a Patella, for which it is often mistaken on account of the lower valve being very thin, flat, and adhering.

Shell sub-orbicular, very compressed, inequilateral, very inequivalve; the inferior valve very thin, adherent, and imperforated; the superior valve like a Patella, with a summit more or less inclined towards the posterior side.

_O. Norwegica._ The Norwegian Orbicula. Pl. 17, fig. 4.

Upper valve in the form of a depressed cone, with a summit produced and pointed.

2. Terebratula. Twelve species.

Taken from the Anomia, and with great propriety, as its characteristic differences are very great; the perforation of the Anomia is always in the smaller valve, which is attached to the larger by a cardinal ligament, while in the Terebratula the perforation is always in the larger valve, which is connected to the smaller by teeth at the hinge. In some the valves are smooth, and in others grooved longitudinally.

Shell thin, equilateral, sub-triangular, inequivalve; one of the valves larger and more convex than the other, prolonged behind by a sort of heel, sometimes recurved, and pierced by a round hole at its extremity; frequently sloped more or less by a cleft of variable form; the opposite valve smaller, more flat, sometimes formed like a lid, having in the interior a system of support variable in form and complication in every true species; hinge limited, prominent, and formed by two articulating surfaces of one valve placed between corresponding projections of the other; a kind of tendinous ligament issuing from the sloping cleft of the shell, by which it is attached to marine bodies.

Terebratula vitrea. T. dilatata. T. rotunda. T. flavescens. T. dentata. T. dorsata. T. pisum. T. globosa. T. sanguinea. T. caput-serpentis. T. truncata. T. psittacea.

_T. dorsalis._ The dorsal Terebratula. Pl. 17, fig. 1.

The summit of the large valve pierced with a round hole, very circumscribed; grooved longitudinally; valves as if cut sloping in the middle line.

_T. globosa._ The globose Terebratula.

Species smooth, with the valves rounded at their anterior edge.

_T. caput serpentis._ The Serpent’s-head Terebratula.

Species grooved, with the summit or heel of the large valve deeply hollowed even to the edge of the articulation; the slope rounded; the valves sub-bilobate by the apparent slope of the anterior edge.

3. Lingula. One species.

The valves of this genus are united by means of a tubular, fleshy, or membranous peduncle surrounding the narrow part of them, and of which the base is affixed to marine substances.

Shell covered with epidermis, sub-equivalve, equilateral, depressed, elongated, truncated anteriorly, summit middle and posterior, without trace of ligament, but supported at the extremity of a long fibro-gelatinous peduncle, which attaches it vertically to sub-marine bodies; multiple muscular impression.

_L. anatina._ The Duck’s-bill Lingula. Pl. 17, fig. 2.

Covered with a green, shining epidermis, shaped like a duck’s bill, and having a cylindrical peduncle.

CLASS IV. MOLLUSCA. TWENTY-TWO FAMILIES.

FAMILY I. PTEROPODA. Six genera

Some genera of this family are without a testaceous covering, and are mentioned only for the sake of preserving the family entire.

1. Hyalæa. Venus’s Chariot. Two species.

This genus derives its common name from a fancied resemblance to a miniature triumphal car.

Shell very thin, transparent, symmetrical, convex below, flat above, valves unequal, form tricuspidated, cleft at the sides, open like a cleft anteriorly, and tridentated posteriorly; summit truncated.

Hyalæa tridentata. Hyalæa cuspidata.

_H. tridentata._ The three-toothed Hyalæa.

Transparent, horn-coloured, globular; tridentated posteriorly; summit and two posterior sides open; finely striated transversely.

2. Clio. Has no Shell. Two species.

Clio Borealis. Clio Australis.

3. Cleodora. Two species.

Shell gelatinous, cartilaginous, transparent, in shape of a reversed pyramid or lanceolate truncated, only open at the summit.

Cleodora pyramidata. Cleodora caudata.

_C. pyramidata._ The pyramidal Cleodora.

Like a pyramid, triangular, thin, transparent; aperture obliquely truncated.

4. Limacina. One species.

Shell papyraceous, very fragile, planorbis form, sub-carinated, involuted rather obliquely, in such a manner as to be deeply and largely umbilicated on one side, and the spine slightly projecting and pointed on the other; aperture large, entire.

_L. helicialis._ The Helix-like Limacina.

Thin, fragile, spiral; the volutions united in a discoid form.

5. Cymbulia. The Slipper. One species.

Shell or case cartilaginous, transparent, conical posteriorly where the animal adheres, and prolonged above like a long hollow semi-cylinder, under which the animal can take shelter.

_C. Peronii._ Peron’s Cymbulia.

Shell shaped like a shoe, somewhat gelatinous or cartilaginous, very transparent crystalline, oblong pointed at the vertex, truncated at the base.

6. Pneumodermon. Has no shell. One species.

P. Peronii.

FAMILY II. PHYLLIDIACEA. Four genera.

1. Phyllidia. Three species.

The animals of this genus are covered with a coriaceous skin, but without a shell.

Phyllidia varicosa. P. pustulosa. P. ocellata.

2. Chitonellus. Two species.

Formerly classed with the Chiton; but as the testaceous plates of this genus are never joined, the two may be easily distinguished.

Shell elongated, multivalve; alternate pieces generally longitudinal; sides naked.

Chitonellus striatus. Chitonellus larvæformis.

_C. striatus._ The striated Chitonellus.

Striæ radiating from the apex of each valve; margin serrated; base of the last valve obtuse.

_C. larvæformis._ The Caterpillar Chitonellus.

More or less cylindrical, almost naked; the valves of the shell very small, and almost entirely concealed under the skin; tufts hairy or silky between the parts of the valves near the margin.

3. Chiton. Six species.

This genus was so called from the resemblance of its testaceous covering to a coat of mail. The form of the Chiton is very similar to a well-known insect called the woodlouse, found in decayed timber; it generally adheres to rocks, or lies rolled up like a ball among seaweed and stones. In length it seldom exceeds an inch, except in tropical climates, where they are sometimes three or four inches long. In general there are eight valves, the termination of which is surrounded by a scaly or rough ligament, which enables the animal to expand or contract its shell freely. It presents a great variety of colour; in general it is dark brown, overcast with a shade of green, but some are beautifully variegated with pink, yellow, blue, or red; interior green or whitish.

Shell more or less elongated, consisting of a longitudinal series of eight very symmetrical calcareous pieces, more or less curved, and round at both extremities; summit more or less marked, and when imbricated, always from front to rear.

Chiton gigas. C. squamosus. C. Peruvianus. C. spinosus. C. fascicularis. C. marginatus.

_C. squamosus._ The scaly Chiton. Pl. 1, fig. 1.

Depressed, valves large, carinated, well imbricated; the interstices offering well-marked lateral spaces; the border of the mantle regularly scaly.

_C. marginatus._ The marginated Chiton. Pl. 1, fig. 2.

Valves carinated and projecting over each other; finely shagreened, with a dusky reddish-brown margin.

_C. fascicularis._ The fasciculated Chiton. Pl. 1, fig. 3.

Valves more narrow, imbricated, without distinct spaces; lateral parts of the skin naked or hairy, but always provided with silky or hairy tufts disposed in pairs between the junctions of the valve.

_C. spinosus._ The spiny Chiton. Pl. 1, fig. 4.

Shell beset with long, thin, curved, tubular, hairy, blackish spines.

4. Patella. The Limpet or Dishlike Shell. Forty-five species.

The Patella of Linnæus was divided by Lamarck into several distinct genera, and now comprehends only such shells as are of a conical form, with an imperforated summit. The anterior is that part to which the summit inclines, and is always more narrow than the posterior part.

It derives its name from its resemblance to a little dish; the colour and structure are various; some are smooth, others granulated, and many are covered with elevated tuberculated ribs. The exterior is sometimes of a pale fawn colour, and the interior of a bright pink; some have a silvery hue, but the more general colour is bluish white or light brown.

This genus of shells is very numerous in all seas, but chiefly in hot countries, where they are found of a larger size; they generally adhere by their base to rocks, stones, and marine substances, from which it is difficult to detach them.

Shell oval or circular, sub-conic; summit right or more or less recurved anteriorly; the cavity simple, entire, more or less deep; the margin complete and entirely horizontal; a narrow muscular impression.

Patella apicina. P. granatina. P. oculus. P. barbara. P. plicata. P. laciniosa. P. saccharina. P. angulosa. P. barbata. P. longicosta. P. spinifera. P. aspera. P. luteola. P. pyramidata. P. umbrella. P. plumbea. P. cærulea. P. radians. P. scutellaris. P. viridula. P. pectinata. P. Galathea. P. Safiana. P. testudinaria. 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. cymbularia.

_P. vulgata._ The common Patella. Pl. 2, fig. 1.

Conic, summit obtuse and vertical; sometimes ribbed from the vertex to the margin with divergent striæ, sometimes striated without ribs; exterior dark brown or greenish, internal blue or purple radiations.

_P. compressa._ The compressed or flat-sided Patella. Pl. 2, fig. 2.

Oval, elongated, compressed on the sides, having the summit sub-anterior, well marked, and curved; exterior fawn colour, interior of a silvery hue.

_P. deaurata._ The golden red Patella. Pl. 2, fig. 3.

Sub-conic, summit more anterior, with a slight forward inclination; colour yellowish red.

_P. cochlear._ The spoonlike Patella. Pl. 2, fig. 4.

Depressed, the summit hardly marked, and much more narrow in front than behind; exterior brownish, interior light blue.

_P. scutellaris._ The buckler Patella. Pl. 2, fig. 5.

Depressed, summit sub-anterior, radiated from the summit to the margin; brown colour, with a yellowish band parallel to the margin.

_P. pectinata._ The pectinated Patella. Pl. 2, fig. 6.

Oval, summit well marked and anteriorly inclined; ribbed from the summit to the margin, which is slightly convex in the middle.

_P. cymbularia._ The cymbular Patella. Pl. 2, fig. 7.

Oval, thin, pearly, with a festooned margin; summit nearly marginal; colour white, shaded with very light brown.

FAMILY III. CALYPTRACEA. Seven genera.

The genera that constitute this family were separated by Lamarck from the Patella of Linnæus.

1. Parmaphora. The Duck’s-bill Limpet. Three species.

The characteristic distinctions of this shell were first pointed out by De Blainville.

Shell elongated, very depressed; the summit greatly post-medial, and evidently inclined behind; aperture as large as the shell; the lateral edges straight and parallel, the posterior rounded, the anterior sharp and notched in the middle; muscular impression large, elongated oval, slightly open in front.

Parmophora Australis. P. brevicula. P. granulata.

_P. Australis._ The Australian Parmophorus.

Shell oblong, depressed; vertex slightly recurved; striated concentrically; one margin rounded, and the other truncated.

2. Emarginula. The Slit Limpet. Four species.

Most of the shells of this genus are small; some are elevated, and others of a widely-depressed conical form.

Shell conical, recurved; summit entire; slit, or more or less hollowed on the anterior side; a muscular impression in form of a horseshoe, open behind and thicker at the beginning.

Emarginula Blainvillii. E. marginata. E. fissura. E. rubra.

_E. Blainvillii._ Blainville’s Emarginula.

Shell with the notch or slit in the middle of the back, and not extending to the margin.

_E. fissura._ The slit Emarginula. Pl. 32, fig. 5.

Oval, compressed, summit well marked, with reticulated striæ and ribs; fissure extending half way from the margin to the summit; exterior light brown, interior white.

_E. marginata._ The marginated Emarginula.

More compressed than the preceding; summit distinct, anterior margin formed like a gutter.

3. Fissurella. The Keyhole Limpet. Nineteen species.

The perforation not being perfectly round, but generally ovate oblong, procured for this genus its common name, by which it is easily distinguished.

Shell simple, conical, depressed, recurved; summit perforated a little anterior in an oblong or oval manner, like a keyhole; the exterior surface ribbed longitudinally, slightly striated transversely.

Fissurella picta. F. nimbosa. F. crassa. F. Græca. F. nodosa. F. Cayennensis. F. lilacina. F. rosea. F. Barbadensis. F. radiata. F. viridula. F. hiantula. F. pustula. F. fascicularis. F. Javanicensis. F. depressa. F. Peruviana. F. gibberula. F. minuta.

_F. nimbosa._ The scaly-ribbed Fissurella.

Species of which the middle part of the edges of the aperture is hollowed in such a manner that, when placed on a level surface, they touch only at the extremities.

_F. rosea._ The rosy Fissurella.

Species more depressed, edges bent up lengthwise, forming a kind of canal.

_F. Græca._ The Greek Fissurella. Pl. 32, fig. 1.

Conical, ovate oblong; striæ cancellated and elevated; sections tuberculated; exterior yellowish brown or clouded, interior white or light blue.

4. Pileopsis. The Caplike Limpet. Four species.

Easily distinguished by its form, which gave rise to the common name.

Shell oblique, sharp pointed; cone bent forward, with a recurved, almost spiral summit, finely striated longitudinally and slightly wrinkled transversely; aperture a round oval; the margin at the base nearly round, more or less regularly crenated and indented, interior with a lengthened, arched, transverse muscular impression.

Pileopsis ungarica. P. mitrula. P. intorta. P. subrufa.

_P. ungarica._ The Fool’s Cap.

Conical, vertex slightly spiral, pointed, and recurved; exterior pale fawn colour, and the outer margin bordered with a fringed epidermis; interior sometimes of a very bright pink or rose colour.

5. Calyptræa. The Cup and Saucer Limpet. Four species.

This genus of shells is remarkable for having in the interior cavity a transverse funnel or tongue-shaped testaceous appendage, from which originated its common name.

Shell conic, base orbicular; summit vertical and imperforated; cavity deep, having at its interior summit a tongue-like appendage. This appendage is sometimes vertical and sometimes like a horseshoe, having on it a muscular impression of variable form.

Calyptræa extinctorium. C. lævigata. C. equestris. C. tectum-sinense.

_C. extinctorium._ The extinguisher Calyptræa.

Species in which the internal appendage is horn-shaped; colour brownish.

_C. equestris._ The equestrian Calyptræa. Pl. 32, fig. 4.

Species in which the internal appendage is like a horseshoe, open in front.

_C. tectum-sinense._ The Chinese roof Calyptræa.

Shell formed of separate, transverse, irregular round laminæ of uniform size, attached to each other by the summit on the exterior of each, presenting the appearance of a number of small flat Patellæ piled one on the other; colour yellowish, margin entire, very glossy within.

6. Crepidula. The Slipper Limpet. Six species.

Very similar to the Navicella, but distinguished from it by not having an operculum.

Shell irregular, form very variable, depressed or compressed; spire obliquely inclined to one side; margin entire; cavity large, divided by a horizontal partition, which gives it the form of a half-decked boat.

Crepidula fornicata. C. porcellana. C. aculeata. C. unguiformis. C. dilatata. C. Peruviana.

_C. porcellana._ The brown-spotted Crepidula.

Shell thick, flat, summit not spiral.

_C. aculeata._ The prickly Crepidula.

Oval, brown, roughly striated, vertex recurved, interior blue or purple.

_C. sub-spirata._ The sub-spiral Crepidula. Pl. 32, fig. 2.

Species almost round, summit sub-spiral; colour yellowish white, with a bluish tinge towards the summit.

7. Ancylus. The Lake Limpet. Two species.

This is a fresh-water shell, found in the lakes of Europe.

Shell thin and brittle, obliquely conical; summit pointed and recurved; margins simple, base oval and smooth.

Ancylus oblongus. Ancylus fluviatilis.

_A. oblongus._ The oblong Ancylus.

Aperture elongated, vertex turned to one side, striated concentrically; exterior pale yellowish colour, interior light blue.

_A. fluviatilis._ The river Ancylus. Pl. 32, fig. 3.

Simple, oval, almost symmetrical; summit pointed, compressed, very distinct; bent back a little to the right, but not marginal; the edges of the aperture entire and effuse.

FAMILY IV. BULLACEA. Three genera.

1. Acera. Has no shell. One species.

Acera Carnosa.

2. Bullæa. One species.

Formerly classed with the Bulla, but separated from it on account of the shell being entirely covered by the animal, and never externally visible.

Shell oval, thin, fragile, more or less involuted on one side, rendering the aperture more or less wide.

_B. aperta._ The open Bullæa. Pl. 17, fig. 5.

Shell interior and very incompletely involuted, without spire or columella; sub-orbicular, white, transparent, faintly striated, and slightly wrinkled; almost entirely open.

3. Bulla. The Bubble. Eleven species.

The great confusion that existed in this genus, as classed by Linnæus, has been elucidated by the division and classification of Lamarck. This genus derived its name from the resemblance which some of the smaller species have to a bubble of water. Its shells are found in almost all parts of the world.

Shell external, oval, involuted; aperture very large, open the whole length of the shell, and generally wider at the base; outer edge sharp and smooth; summit umbilicated.

Bulla lignaria. B. ampulla. B. striata. B. naucum. B. physis. B. fasciata. B. aplustre. B. hydatis. B. cornea. B. fragilis. B. solida.

_B. aplustre._ The streamer-like Bulla. Pl. 17, fig. 7.

Species completely involute; the spire very distinct, visible, but not projecting, with a kind of thickening at the anterior part of the columellar edge.

_B. lignaria._ The woodlike Bulla.

Species sub-involute, no visible spire either within or without, but narrowed towards the top when it is slightly umbilicated; yellowish brown colour, with transverse pale striæ.

_B. hydatis._ The watery Bulla.

Species more solid, thicker, almost entirely involute; whorls of the spire slightly visible in an umbilicus projecting interiorly from the summit.

_B. naucum._ The sea-nut Bulla.

Species thin; the whorls of the spire visible externally, but without projection, and with a suture as if caniculated without thickening at the anterior part of the columellar edge.

_B. fragilis._ The fragile Bulla.

Species very thin, rather involute; the whorls of the spire distinct within as without; the suture deep, angular, and cleft in a greater or less part of its length.

FAMILY V. APLYSIACEA. Two genera.

1. Aplysia. Three species.

This genus may almost be said to have no testaceous covering, as it appears more like the element of a shell.

Aplysia depilans. A. fasciata. A. punctata.

_A. depilans._ The bald Aplysia.

Shell dorsal, semicircular, of a thin yellow cartilaginous substance.

2. Dolabella. Two species.

Closely allied to the Aplysia; it is a singularly formed shell, difficult to describe, as it contains few of the characteristics which distinguish other shells.

Shell rudimentary, entirely flat, sub-spiral, with a summit thick and very callous.

Dolabella Rumphii. Dolabella fragilis.

_D. Rumphii._ Rumphius’s Dolabella.

Base thick, callous, and sub-spiral; dilated above, thin, and wedge-shaped.

FAMILY VI. LIMACINEA. Five genera.

1. Onchidium. Has no shell. Two species.

Onchidium Typhæ. Onchidium Peronii.

2. Parmacella. One species.

Lamarck has given a description of the animal of this genus, but only mentions that the scutcheon contains a shell or solid crustaceous body.

Parmacella Olivieri.

3. Limax. Four species.

The animal belonging to this genus is furnished with a coriaceous shield, wrinkled.