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VOLVARIA, Lamarck. 



Gen. Char. Shell cylindrical, convoluted; spire 

 almost hidden ; aperture as long" as the shell, 

 narrow, widest towards the truncated base ; 

 outer lip denticulated ; columella plaited. 



The principal characters of this Genus, as limited by 

 Mr. G. B. Sowerby, are, the plaited columella, the 

 striated surface, the truncated base, and the thin edge of 

 the outer lip : by its convoluted form and short spire it 

 is related to Bulla ; the plaits upon the columella form 

 a resemblance to Marglnella ; but its nearest affinity is 

 to Acteon (Tornatella, Lam.), from which its concealed 

 spire, numerous plaits, and truncated base distinguish it. 

 The Genus, as established by Lamarck, contains several 

 recent species, which Mr. G. B. Sowerby has justly ob- 

 served are more naturally related to Marginalia, from 

 which however they differ in some characters. The 

 striated surface, from whence arises the denticulated 

 edge of the lip, is important as a generic character, be- 

 cause it indicates the presence of an epidermis, and that 

 the shell was never enveloped in the mantle of its in- 

 habitant ; and thus marks a decided distance between it 

 and the recent shells Lamarck has arranged with it. 



