CONCKOLOGY. 113 



8. Achatina. Twenty species. 

 This likewise is an elegant genus of shells, classed by- 

 Linnaeus 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. Achatina immaculata. 



A. zebra. A. purpurea. 



A. acuta. A. ustulata. 



A. bicarinata. A. vexillum. 



A. Mauritiana. A. Virginea. 



A. castanea. A. Priamus. 



A. glans. A. fulminea. 



A. Peruviana. A. columnaria. 



A. albo-lineata- A. folliculus. 



A. fusco-lineata. A. acicula. 



A. Virginea. The Virginian Achatina. 



Smooth, conoid, with aperture almost round ; very shorty 

 grayish white, with red and black transverse bands ; colu- 

 mella rose-coloured, with one plait ; volutions ventricose ; 

 inside of the lips bluish ; a transverse callosity in the inte- 

 rior. 



A. zebra. The zebra Achatina. PI. 18, fig. 1. 



Species thin, oval, sub-ventricose, spire prominent, striped 

 like a zebra. 



A. glans. The acorn Achatina. PI. 18, fig. 2. 

 Species sub-turriculated, of which the last whorl is attenu- 

 ated anteriorly. 



P 



