_B. hæmastomus._ The rose-lipped Bulimus. Species oval or of ordinary form. _B. ventricosus._ The ventricose Bulimus. Species ventricose, from which circumstance it derived its name. _B. radiatus._ The radiated Bulimus. Pl. 19, fig. 7. Species turriculated. _B. citrinus._ The citron Bulimus. Species sinistral. _B. multifasciatus._ The many-banded Bulimus. Species slightly umbilicated. 8. Achatina. Twenty species. This likewise is an elegant genus of shells, classed by Linnæus with the Bulla. They are the largest land-shells known, and greatly resemble the Bulimus, but never have their lips reflected or thickened. Sometimes the last whorl is compressed and attenuated at the base, and sometimes ventricose and not compressed. Shell in form very variable, but generally sub-turriculated, ventricose, striated longitudinally; the summit papillose; aperture a little variable, but never thickened or reflected; the right edge always acute, the columellar margin rather strongly hollowed, entirely formed by the columella, of which the anterior extremity is constantly open and truncated. Achatina perdix. A. zebra. A. acuta. A. bicarinata. A. Mauritiana. A. castanea. A. glans. A. Peruviana. A. albo-lineata. A. fusco-lineata. A. immaculata. A. purpurea. A. ustulata. A. vexillum. A. Virginea. A. Priamus. A. fulminea. A. columnaria. A. folliculus. A. acicula. _A. Virginea._ The Virginian Achatina. Smooth, conoid, with aperture almost round; very short, grayish white, with red and black transverse bands; columella rose-coloured, with one plait; volutions ventricose; inside of the lips bluish; a transverse callosity in the interior. _A. zebra._ The zebra Achatina. Pl. 18, fig. 1. Species thin, oval, sub-ventricose, spire prominent, striped like a zebra. _A. glans._ The acorn Achatina. Pl. 18, fig. 2. Species sub-turriculated, of which the last whorl is attenuated anteriorly. _A. columnaris._ The columnar Achatina. Pl. 18, fig. 3. Species evidently turriculated. 9. Succinea. Three species. A terrestrial shell, though the animal that inhabits it is almost amphibious; it greatly resembles the Bulimus, but is easily distinguished by never having the lip reflected or thickened.