Conchology or Testaceology is a numerous and beautiful branch of Natural History, treating of the testaceous covering of animals; perhaps none but the department of Flora can vie with it in variety, symmetry of form, and rich colouring. It has ever excited admiration, and obtained a prominent situation in the cabinet; and so great are the facilities afforded at the present day to procure specimens and obtain a knowledge of this science, that it has become one of the requisites of a finished education. Shells are found in all parts of the world, both on land and in water; but the most beautiful and valuable species are found between the tropics.

At first they were regarded as pleasing curiosities, and prized only on that account; but the investigations of scientific men have proved that the study of this science is not only interesting, but useful. Much valuable information has already been obtained, and, from the investigations of modern naturalists, much more may be anticipated.

So intimate is the connexion between Conchology and Geology, that a knowledge of the one is indispensable to the study and acquirement of the other. The geologist will draw much advantage from a close study of the testaceous covering of molluscous animals to aid him in determining the identity or the superposition of the different strata of the earth and the extraordinary changes it has undergone; for, as Bergman elegantly says, “fossil shells, coral, and wood are the only three remaining medals of Creation.” He will see in the innumerable quantity of these animals, succeeding each other from generation to generation in the depth of the seas, one of the evident causes of the growth and increase of islands and continents.

But man may find in the knowledge of Mollusca applications still more direct to his well being in society, both as to the advantages and disadvantages to be derived from them: thus a great number of species are proper for food, as oysters, mussels, &c., which are objects of commercial speculations. The Pinna furnishes the Italians with materials for a rich dress, and the pearl, so much prized by the Orientals, by princes, and particularly by the ladies, as a modest and beautiful ornament, is produced by a disease of the animals in certain species of shells. It was this knowledge which made the celebrated LinnÆus imagine that it was possible to form an artificial pearlery in the rivers of Sweden. The mother of pearl, so much employed as an ornament in articles of luxury, is only the interior lining of certain univalve or bivalve shells. Painting draws from some of these animals many colours, valuable not so much for their beauty as their usefulness, as Chinese ink and sepia.

The brightest and richest colour known by the ancients, and used by them for the celebrated Tyrian purple dye, is produced by animals at this time known by the name of Purpura.

The Teredo attacks the wood of our vessels, and often does much injury; therefore the knowledge of its manners, habits, and customs must be of great importance in countries infested with them, so as to be able to provide a remedy against them. Snails and slugs are also enemies much to be dreaded in our gardens.

Lamarck, in his last work, the result of the successive and continual labours of his whole life and those of his contemporaries, has rendered a very great service to science, but especially to conchology, by describing, or, at least, characterizing the numerous species of shells in his own splendid cabinet. It may be proper here to remark, that a part of Lamarck’s cabinet is now in the possession of Isaac Lea, Esq., of Philadelphia, to whom we are much indebted for valuable assistance. To Dr. Comstock, and the Rev. W. Turner, of Hartford, Conn., we are much indebted for kind favours; their aid has greatly facilitated our labours.

In this Manual of Conchology we have endeavoured to give a free translation of Lamarck’s system, as simplified by De Blainville; and, in order to facilitate as much as possible the study of this beautiful and interesting science, we have divested it of numerous technicalities, and divided it into four classes: Annelides, Cirrhipedes, Conchifera, and Mollusca.

To each class we have assigned its various families, to each family its genera, and to each genus its living species; thereby making it plain and within the reach of the meanest capacity. A type of almost every genus is given, excepting only those shells which, from their similarity to other genera, may easily be classed.

It was deemed advisable, as this is intended for an easy introduction to the science, to omit many divisions and subdivisions, which would only serve to perplex and render the attainment more difficult.

As the Naiades, or shells of this country, are given in several valuable scientific works lately published, we have only slightly touched them in the place they are intended to occupy.

We cannot expect that the work now presented to the public is free from imperfections; but we ask for their lenity and kind forbearance to excuse whatever defects there may be in our humble attempts to advance the cause of science. Conchology, like other departments of natural history, is progressing; and that which is given to-day is almost always susceptible of being modified to-morrow; should this work be well received, it is our intention to give, as soon as practicable, an enlarged work, containing even the minute microscopic shells and the fossils, with plates containing types of as many species of the genera as can possibly be obtained.

The plates were drawn and coloured with great care and accuracy from the natural shells in our own cabinet, under the superintendence of Mr. James Ackerman, artist.