The term Mollusc, from _mollis_, soft, is intended to express that the whole class are invertebrate; that is, entirely without spine, or any bony support to their curious fleshy forms. The term was invented by the illustrious Cuvier, but is objectionable as a distinctive one, the characteristic on which it is founded being shared by other distinct classes of animals. When, however, the application of a term is well understood, its inner signification becomes unimportant; it is, therefore, now too late to criticise the one invented and applied by the prince of modern naturalists. Among the interesting facts detected by recent science, it has been shown that many of the seemingly shapeless masses of soft substance, scarcely to be termed flesh, possess all the senses of the higher animals. In the _Cephalopoda_, the organs of sight and hearing are both well developed; and Professor Owen considers that the Nautilus possesses even an organ of passive smell. The _Gasteropoda_ too, are, according to Siebold, nearly all furnished with ears and eyes, the former organs being described as forming round capsules, conspicuously visible near the roots of the tentacles. Some of the _Conchifera_, also, are furnished with numerous eyes, which, like those of the Scallops and Clams of our own shores, are also placed among their tentacula. It appears probable, says Dr. Johnston, that many have also the sense of taste, as they are observed to select particular articles of food in preference to others, and there is no other sense that appears fitted to regulate the choice. The mouth, as it is termed, of many of the molluscous tribe is furnished, as among the _Gasteropoda_, with a fringe formed of filaments, which may be organs of touch, and they have also a complicated breathing apparatus. The strength of these boneless creatures is something very extraordinary, and almost incomprehensible. The _Strombus gigas_, a soft, snail-like creature, carries a shell which often weighs more than five pounds; the _Cassis tuberosa_ supports one nearly as heavy, and the naked Molluscs, that have no shell to carry, have other modes of exhibiting strength of a very extraordinary character.