TROCIIOCOCIILEA. 425 



Genus BANKiviA, Beck. 



Shell subulately conical, porcellanous ; spire elevated, 

 acute, whorls flat, smooth, without epidermis; aperture 

 small, sub-quadrangular, not pearly within ; columella 

 twisted, truncate anteriorly ; outer lip acute, simple. 



Ex. B. varians. Beck, pi. 48, fig. 6. 



The position of this genus among the TrocJiidce is 

 somewhat doubtful, as neither the animal nor operculum 

 are known ; the aperture not being pearly within, and the 

 columella being truncate and tortuous, are against this 

 view, while other characters of the shell seem to assimi- 

 late the genus to Elenchus and Ziziphinus. 



Species of Bankivia. 



major, A. Adams. varians, Beck. 



nitida, A. Adams. 



Genus TROCHOCOCHLEA, Klein. 



Shell solid, conoidal, imperforate in the adult ; whorls 

 smooth or transversely lirate, the last rounded at the peri- 

 phery ; aperture nearly rhomboidal; columella thick and 

 rounded, ending anteriorly in a slightly-prominent tu- 

 bercle. 



8y)i. Trochius, Leach. Gibbium, Gray. Osilinus, 

 Phil. Labio, Gray, not Oken. Melagraphia, Steniz. 



Ex. T. tseniata, Quoy and Gaimard, pi. 48, fig. 7. 

 Operculum, T. constricta, Macleay, fig. 7, a. Shell, 

 T. constricta, fig. 7, b. 



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