"The naturalist Bruguieres established the fine genus _Cerithium_, mixed by Linnæus among those of _Murex_, _Strombus_, and _Trochus_. These shells are always turreted, having a short canal at the base; the aperture oblong, oblique, with a gutter turned backwards. (See Frontispiece.) Many are girded with zones, that are granulated, or beset with little tubercles. It is remarkable that _Cerithium giganteum_, a species more than a foot in length, is found fossil in France, and as a living species in the seas of New Holland. _C. telescopium_ is a fine shell from the East Indies. _C. vertagus_ is smooth, tawny-white, with a recurved canal. It comes from the Moluccas. Many species occur fossil in London clay and in plastic clay: the Woolwich pits afford specimens, and also of _Turritella_. "_Pleurotoma_, formerly united with _Murex_, is distinguished by the singular _notch_ in the right-margin of the shell. One species, the Tower of Babel, is well-known, and another is common under the name of _Murex javanus_. The fossil species are numerous. "_Turbinella_ is taken from _Murex_ and _Voluta_: some species are thick, heavy shells, from the Indian seas. "_Cancellaria_ is an elegant genus: the shells are varicose, reticulated, or cancellated; the columella has folds upon it, varying in number, the right-margin sulcated within. There are several fossil species, which are considered very beautiful. "_Fasciolaria trapezium_, the Persian robe, is a fine shell from the Indian seas, very common in collections. [Sidenote: FUSUS. PYRULA. RANELLA.] "The genus _Fusus_ consists of spindle-shaped shells, of which _Fusus colus_, the distaff, will give an idea. They are covered with an epidermis which conceals, in some species, the fine colours beneath. "_Fusus despectus_ (_Murex_ of Linnæus) is the largest of the British turbinated shells, and very common: it is the large whelk. "_Fusus contrarius_, the reverse whelk, is found fossil in the Essex crag. "Among the shells of the _Pyrula_ genus we find _P. ficus_, the fig, placed by Linnæus among the _Bulla_ race. _P. spirillus_ is a pretty species, with a long canal and a flattened spire, having a tubercle at its termination. * * * * * "Second section of _Canalifera_: shells with a varix on the right-margin. _Struthiolaria_, } _Ranella_, } _Murex_. _Murex_, } _Triton_, } "_Struthiolaria_, ostrich-foot, is a remarkable shell from New Zealand. "_Ranella_, thorny-frog, is frequent in collections: there are several species: _R. crumena_ is easily obtained--you must purchase a specimen. [Sidenote: MUREX. TRITON.]