We have experienced some surprise in observing that while so much attention has been bestowed by writers upon the generical distinctions of Voluta Pyrum, the differences that prevail in its presumed varieties have almost entirely escaped attention. It should be remarked that in the Gmelinian constitution of this species there are no less than four distinct varieties, all which, according to Gmelin, and subsequently to other writers, appertain to the Linnæan species Pyrum. From the synonymous references which Lamarck has brought together in one view, it is obvious that his opinion is the same; his TURBINELLA PYRUM, which is the same as the Linnæan Voluta Pyrum, will be observed to comprehend the several presumed varieties of the species to be found in the works of Martini and Chemnitz, and the same is again observable in the works of Denys de Montfort. There are, however, some Conchologists in England who do not agree in this particular, for they constitute at least three distinct species of the presumed varieties of Voluta Pyrum. This division of the species was first proposed by Dr. Solander, and has been subsequently adopted in several of our English Cabinets. As the particulars of this arrangement may not prove unacceptable, we shall proceed to describe them. To the _first_ of these new species Dr. Solander retains the Linnæan name of VOLUTA PYRUM, it is that kind which has the beak elongated, and is known by the familiar name of the LONG BEAKED TURNIP SHELL. This is the Voluta rostrata of some Conchologists; Rapum rostratum of the Colonnian Museum; and inhabits the seas of Tranquebar. As the preceding shell is distinguished by the name of the Long beaked Turnip Shell, in allusion to the elongated structure of the beak, there is another known by the appellation of the High Spired Turnip Shell, in reference to the greater elevation of its spire; this is a _second_ species of Solander, and is called by him VOLUTA PONDEROSA; in the Calonnian Museum it stood under the name of Rapum productum. This shell inhabits the seas of Madagascar, and is the kind which becomes the more immediate object of our consideration as the subject of our present plate. The _third_ kind of Turnip Shell is from the straits of Malacca, a shell more ponderous than the preceding; of a broader form and having the spire more depressed. This is the common Heavy Turnip Shell of our English Cabinet, Voluta gravis of Solander.