96 AURICULID^. 



TRALiA, Gray, 1840. Shell oval, smooth, spire moderate ; 

 aperture narrow, linear, wider in front ; columellar lip with three 

 oblique plications ; outer lip sharp, sinuous posteriori}^, inter- 

 nally callous, with one or several strong revolving ribs. Foot 

 not transversely divided, the posterior extremity attenuated, 

 not bifid. West Indies. M. pusilla, Gmel. (cii, 81). Should, 

 perhaps, be considered a distinct genus. 



PiRA, H. and A. Adams, 1853. Shell oval, smooth ; spire 

 elevated ; aperture linear ; columellar lip usuall}^ with three 

 anterior plications ; outer lip with numerous revolving riblets, 

 forming tooth-like terminations. M. angiostoma ^Desh. (cii, 82). 



TirATA, H. and A. Adams, 1853. Shell oval or elliptical; 

 aperture narrow, contracted, curved ; columella produced, with 

 two lamellar plications ; outer lip smooth or minutely dentate 

 within, margin acute. M. oliva, d'Orb. (cii, 83). 



SIGNIA, H. and A. Adams, 1855. Shell decussate or granular ; 

 columellar lip with transverse plaits ; outer lip with a simple 

 elevated transverse plication upon its inner face. M. graniferus, 

 Mouss. (cii, 84), 



PERSA, H. and A. Adams, 1853. Shell oval, with longitudinal 

 ribs and revolving striae ; aperture rather large ; outer lip sharp, 

 smooth within ; columellar lip with transverse lamellar plications. 

 M. costatus, Quoy (cii, 85). 



DETRACiA, Gray, 1840. Columellar wall not plicate, aperture 

 very narrow. M. cingulatuH, Pfeiffer. West Indies. 



Rhytiphorus, Meek, 18*73. 



JDistr. — JR. priscus, Meek {Gu, SI). Cretaceous; Utah. 



Shell having the general aspect of Melampus, excepting that 

 it has a series of small, oblique, short folds around the top of 

 the somewhat shouldered whorls ; while a slight curve in these 

 little folds or costse indicates the presence of a faint sinus in 

 the lip near the suture ; it has two folds on the columella, while 

 the outer lip is thin, and apparently entirely smooth within. 



Ophicardelus, Beck, 1837. 



Distr. — 11 sp. Australia, Polynesia. 0. Australis, Quoy 

 (cii, 86). 



Shell oval-oblong, umbilicated, smooth ; spire elevated-conic ; 

 aperture oval, elongated, angulated above ; inner lip reflected, 

 with two spiral plications, one of which surrounds the umbilicus ; 

 outer lip thin, simple. 



AuTENOE, Guppy. 



Distr. — A. riparia^ Guppy. Trinidad. 



Closely resembling Melampus and Laimodonta, differing 

 chiefly from the former in its thin and horny shell, and from 

 the latter in its short spire and longer aperture. 



