ONISCIA. 



acuminated; aperture longitudinal, elongated, extending 

 at the base into a very short canal : outer lip thickened, 

 denticulated within, and rather contracted in the center) 

 inner lip expanded and covered with granules. 



The outside of the shells of this Genus, in the four 

 species we have seen, is tuherculated, cancellated, or 

 ribbed, and in one, of which we have a young specimen, 

 the spire is terminated by a Minute mamillary point. Of 

 the animal we know nothing, but there is every reason 

 for believing it to be related to that of Cassis, and that 

 it has an operculum, although we have never seen it. Of 

 the species, which we know, three are recent, the O. can- 

 cellata, O. Oniscus, and a new species which we have just 

 received from the South Seas, and which we have named 

 O. tuberculosa. The fourth species is fossil; it occurs in 

 the tertiary formations of Italy. 



We have to acknowledge our obligations to W. J. 

 Broderip, Esq. for the loan of the two specimens we have 

 figured of O. cancellata; and to W. Swainson, Esq, 

 for kindly ceding to us the opportunity of first illustrat- 

 ing this elegant and costly shell. 



In our plate are represented 



Fig. 1 & 2. "Two views of O. cancellata, supposed to have been brought 

 from the Isle of France, it may be characterized as follows : O. supefjieie ex- 

 tcrndj lineis elevatis, cancellatis. 



3. A young shell of the same species. 



4. O. Oniscus. 



5. O. Cithara. Buccinum Cythara, Brocchi Conch. FosiS. Subdpp. tab. V. 

 f. 5. vol. 2. p. 330, found at " Belforte." 



We have rejected the generic term TheUostoma, which 

 had been suggested to us by a Conchological Friend, be- 

 cause it does not appear to convey the meaning intended, 

 viz. that of " granulated mouth." 



f 



