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of this genus from those of the G. Bulla, in which they 

 were classed by Linnaeus. Lamarck has adopted the 

 same association of species, but has divided them into 

 two families; the first consisting of those which have 

 the right side of the aperture wrinkled or thickened; 

 and the second, of such as are smooth on the right 

 side, in which he includes the species that have the 

 last whorl attenuated, and produced in long beaks 

 or rostra at both ends of the shell, as in the O. volva. 

 The G. Ovula, as it is now constituted, forms a very 

 natural association, and precedes the G. Cyprsea, to 

 which it is nearly allied: it is, however, constantly dis- 

 tinguished from the latter by the want of spire, and the 

 left or columella-lip never being plaited or toothed. 

 To the G. Bulla they also approximate, being like them 

 convolute shells; but the right lip, which is constantly 

 folded or reflected inwardly in adult shells, and either 

 smooth or wrinkled, is a character quite opposite to that 

 of the Bulla, in which the lip is thin, sharp, and straight. 

 Shell ventricose, oblong, oval, or egg-shaped ; the 

 whorls convolute, rolled round their own axis; the outer 

 one very large, nearly concealing all the others, and in 

 some species attenuated at both extremities, producing 

 very long subcylindrical beaks, as intheO.\olva, which 

 has somewhat the appearance of a Weaver's Shuttle, 



