ILLUSTRATED INDEX

OF

BRITISH SHELLS.

CONTAINING

FIGURES OF ALL THE RECENT SPECIES,

With Names and other Information.

BY

G. B. SOWERBY, F.L.S.

LONDON:
SIMPKIN, MARSHALL, AND CO., PATERNOSTER ROW
AND
THE AUTHOR, 9, PEMBROKE SQUARE, KENSINGTON.
1859.

PREFACE.

The first idea of this Work arose from the occasional use of Mr. Damon's 'Catalogue of the Shells of Great Britain and Ireland,' named after the 'History of British Mollusca,' etc. Here was, on one side, a very useful list of names, without figures or references to guide an inquirer to the species; and on the other, a very large and splendid Work, placed by its heavy price beyond the reach of Naturalists in general. There was nothing between the two; nothing within reach that would assist collectors of British Shells to name their acquisitions from ocean, beach, river, pond, or hedgerow. A public want seemed here to be discovered. It was thought that a list like the above, with a coloured drawing of every species, if produced at an available price, would supply that want. At first no more than this was thought of, but afterwards, as the preparations advanced, various suggestions were made tending to some extension of the plan. The results are here presented.

About 700 Figures in the Plates represent all the recognized species. They amount to 600, being 60 more than are admitted in the latest monograph. The greater part of these are either new or newly introduced as British. The rest are raised from varieties to species.

As the nomenclature used by Messrs. Forbes and Hanley in their great Work will be most generally adopted in this country, it is followed here with very few alterations; and the synonyms given (in italics) are selected from those which are most familiar and likely to be met with.

Some information is added respecting habits and localities, range of depth of marine species, and comparative abundance. The letters C., Cc., Mc., R., Rr., and Mr., signifying 'common,' 'extremely common,' 'moderately common,' 'rare,' etc., must be taken with great caution, especially the latter, as subject to continual change.

A list is given of British Fossil Shells identical with now living species.

A familiar description of British Mollusca and some peculiarities in their families and genera will, it is hoped, form a useful and suitable introduction to the names and figures. The Author's best thanks are due to his friends, Madame De Burgh, who has collected many beautiful shells; R. M‘Andrew, Esq., F.L.S., whose dredging experiences are so extensive; J. G. Jeffreys, Esq., F.R.S., etc., whose researches have resulted in so many additions to our Fauna; Mr. Brice Wright, the Naturalist, of Great Russell Street, and others, who have in the most liberal manner supplied him with specimens from which his drawings are taken. The loan of delicate and minute shells to authors and artists has so often proved disastrous, that nothing but a generous friendship, and a zealous love of Natural History, could have induced proprietors so freely to incur the risk.

INTRODUCTION

TO

SHELL-BEARING BRITISH MOLLUSCA.

A common garden Snail, observed crawling and feeding, is easily seen to possess a distinct head, upon which are four feelers or horns, with eyes at the end, and underneath which is a mouth; a broad disc, extending the whole length of the body, is the organ of locomotion; a spiral or coiled shell surmounts the whole.

If, on the other hand, an Oyster be opened, no distinct head, or place for eyes or mouth, can be seen, but only a seeming mass of pulp, with a round gristle in the centre (the muscle of attachment), the former enclosed in a soft skin with a double fringe round the edge (mantle), placed within a shell composed of two pieces.

All Mollusca are more or less completely represented by these two. The Snail and its class are named Gasteropoda (abdomen-creeping), and their shells Univalves; the Oyster and its class, Acephala (headless), and their shells Bivalves. We begin with the latter class at—

Plate I.

Pholadidæ, or "Borers," 1-13, have the power of piercing and inhabiting holes in submarine wood, rocks, and stones. The hinder part of the body is lengthened out in the form of a double tube, with openings for the ingress and egress of fluids. Teredo, 1-6, has short valves, two pallets fixed at the sides of the siphons, and lines its hole with a shelly tube. Pholas and Pholadidea, 8-13, have long valves and sometimes accessory plates. The shell of Xylophaga, 7, is like that of Teredo, but the animal has neither pallets nor tube.

Gastrochæna, 14, has a gaping shell, and encloses itself in a bottle-shaped covering of cemented stones and sand. Saxicava, 15, 16, Venerupis, 18, and Petricola, 17, burrow in sand, or live in holes of rocks.

Myadæ, or "Gapers," Mya, 19, 20, and Panopæa, 21, 21*, burrow downwards in sand and mud, their siphons protected by a coriaceous covering. Their shells are not closed all round, and those of Mya have a spoon-shaped process in the hinge of one valve.

Corbulidæ, 22-28, have short siphons with fringed edges, and the foot protrudes through a hole in the otherwise closed mantle.

Plate II.

Poromya, 1, 1*, and the beautiful pearly Pandora, 2, 3, might be included in the family of Corbulidæ. Lyonsia, 4, and Thracia, 5-10, represent the Anatinidæ. 11-18 are Solenidæ, or "Razor-shells." Solens burrow in deep holes in the sand, where they remain in a perpendicular position at a great depth below the surface, where yet their presence may be traced by the opening left. Their large muscular foot enables them to take great leaps when out of the holes.

Plate III.

Psammobia, 1-4, and Tellina, 5-16, include some of our most beautiful shells. The animals have a large, fleshy, curved foot, and the mantle open and fringed. Their shells are provided with an external ligament, and teeth on the hinge. Donax, or "Wedge," 19, 20, has long, separated, fringed siphons. Besides the small external ligament, properly so called, the Mactridæ have a triangular pit in the hinge of their shell, containing an elastic substance or spring, designed to resist the action of the adductor muscles. Mactra, 21-26, ends the Plate.

Plate IV.

Lutraria, 1-3, is another genus of Mactridæ. The Veneridæ, 4-16 and 23, or "Venus" tribe, differ from it in not having the spring-holding pit. Artemis, 10, 11, is known by a large angular bend in the pallial impression; and Cytherea, 23, is distinguished from Venus by one tooth on the hinge standing out a little way from the central ones. Astarte, 17-22, belongs to the Cyprinidæ.