CONCHOLOGY. 



With respect to the general appearance of this shell, the mar- 

 ginate variety of Bulla Achatina, if such it really be, it accords more 

 closely in its colours and markings with Bulla Achatina than with 

 another shell that has been sometimes confounded with it, the Bulla 

 Zebra; the varieties of Bulla Zebra are variable, but it may be 

 generally observed, that it may be easily distinguished by the far 

 greater number of its longitudinal lines, these being numerous, 

 linear, and more distinctly separate, while the dark rays of Bulla 

 Achatina are comparatively few in number, broader, and in parts 

 more confluent, and sometimes even vagariously running into one 

 another. Usually also the B. Zebra is of a paler colour, more 

 fragile, and has the column or pillar lip white, while in Achatina it 

 is more or less purple ; the inside of the mouth in Zebra is also 

 white, while in B. Achatina it is purple, but those latter characters 

 are not always constant, and the intensity or brightness of the colors 

 depends much upon the greater or less perfect condition of the 

 specimen. 



Bulla Achatina is a native of South America, whence also we 

 understand our presumed variety with a reflected lip has been 

 obtained : it is however rare, and esteemed valuable. This shell, 

 like its analogies, is supposed to inhabit the herbage growing in 

 aquatic places, and the animal inhabitant to be furnished with four 

 tentacula, two of which are largest, and that it has two eyes, one of 

 which is situated upon the summit of each of the larger tentacula. 



