PULMONATA. 135 



Scymnia, Leach, 1819. 

 Simmia, Risso, 1826. 

 Calpurna, Fleming, 1828. 

 Volva, Fleming, 1828. 

 CYPRyELLA, Swainson, 1840. 

 Carinea, Swuinson, 1840. 

 Sect. Volva, Bolten, 1798. 

 Radius, Mont/., 1810. 

 Radius, Schum., 1817. 

 Birostra, Swainson, 1840. 



£ew. C'/W. — Shell ovate, gibbous, more or less attenuated or produced, and 

 emarginate at each extremity ; smooth, convolute upon a nearly horizontal plane ; spire 

 concealed : aperture longitudinal, elongated, narrow behind, more expanded in front ; 

 outer lip generally inflected, thickened, denticulated ; inner lip smooth. 



The Ovulae present great similarities to the Cyprsese, both in the organization of the 

 animal and the construction of the shell. The principal distinctions between the 

 animals appear to be in the condition of the muzzle, and in the mantle, the surface of 

 which, in the true Ovuloe, is always smooth. The shells are distinguished by the 

 absence of teeth on the left margin of the aperture, and by the prolongation of the 

 two extremities ; but, like the Cowries, they are, when fully formed, smooth and polished, 

 owing to the enamel-like coating secreted by the extended margins of the mantle. 



The genus was first separated by Gronovius, under the name Ampjtiperas, and was 

 afterwards defined by Bruguiere under the present name, by which it has been generally 

 received. Several dismemberments have been proposed by Bolten, Fleming, Leach, 

 Swainson, and others, on conchological distinctions only. In one of these, the genus 

 Volva proposed by Bolten for the well-known oriental shell, called the " weaver's 

 shuttle," (Ovula volva),the animal, according to Mr. Adams,* presents certain peculiarities, 

 consisting of a row of nipple-like tubercles along the edge of the mantle, and of a 

 narrow foot folded longitudinally and adapted for crawling upon the round slender 

 stems of the Gorgoniae and other zoophytes on which the animal feeds, which modifi- 

 cations appear to confirm the separation; but the other proposed divisions are tor 

 the present received as sections only of the present genus until more accurate knowledge 

 of the anatomy and habits of the animals is acquired. 



The living Ovules are not very numerous, and are, for the most part, inhabitants of 

 warm climates ; they are found principally in the seas of China, Western America, and 

 the West Indies ; one species only is found on our own shores. The fossil Ovules are 

 very few ; seven species from the cretaceous formations, five of which were described 

 as CyprcecB, are referred by D'Orbigny to this genus ; two species, exclusive of 

 0. [Cypraa) tuberculosa, before described, occur in the Eocene tertiaries of France, and 

 three are found in the more recent formations. 



* 'Zoology of the Voyage of H. M. S. Samarang,' p. 19. 



