84 BITHT>"IA. 



BIAPHOLITJS. Leach. A genus believed to be identical with 

 Hiatella. 



BI-ATJKICULATED. Having two auricles placed at the sides 

 of the umboneSj as in Pecten, fig. 171. See Aueictjlated. 



BIMD. Divided, double. 



BIFEONTIA. Deshayes. 1833. Also Omalaxis. Desh. 1830. 

 Fam. Turbinacea, Lam. — Desc/-. Discoidal, planorbicular, with 

 whorls sometimes not contiguous ; umbilicus deep, keeled at the 

 margin ; aperture subtriangular, somewhat dilated ; outer lip 

 acute, separated by a deep notch at both extremities. — Ohs. 

 "We do not see any reason for separating this genus from Sola- 

 EiFM, except the last mentioned character. The few fossil 

 species which this genus contains (Solarium disjunctum, Bifrons, 

 &c.) are found principally in the Paris basin. Solarium Bifrons. 

 PL xvi. fig. 354. 



BI-PUECATB. Double pronged, or having two points. Ex. the 

 internal appendage of Calyptrsea Equestris, fig. 234. 



BIG-ENERINA. D' Orb . A genus of microscopic Eoraminifera. 



BILABIATED. Having the edge of the outer lip as it were 

 doubled, by one part of the lip being more thickened and reflected 

 than the other, so as to form a ledge, or second lip . 



BILOBATE. Having two prominent parts, as the outer lip of 

 Bostellaria Pes-Pelecani, fig. 404. 



BIPABTITE. Composed of or divided into two parts ; as the 

 valves of Platylepas, fig. 19, each of which has a septiform 

 division in the centre ; also the area on the^ Jiinge of the Spon- 

 dylus. See Erontispiece. 



BIEOSTEA. Sw. A genus composed of species of Ovulum, 

 which have elongated extremities, as, for instance, Ovulum 

 Volva, fig. 442. 



BIEOSTEITES. Lam. (Double Beak.) A fossil formerly con- 

 sidered as a distinct bivalve shell, with conical umbones, and 

 placed in the family of Eudistes by Lamarck, but now known to 

 be an internal cast of Sphserulites. PL xi. fig. 196. 



BITHINIA. Gray. 1824, A genus described as differing from 

 Paludina, in having the operculum shelly, and the mouth of 



