TRICHODINA. 191 



Subgenus BOCAGEIA Girard, 1893. 



Bocageia GIR V Jornal de Sciencias Math., Phys. e Nat., 

 Acad. Real Sci. Lisboa, (2), iii, p. 100 (August, 1893), for 

 B. lotophaga Morel. 



"Shell imperf orate, long-oval, solid, sTibtransparent ; spire 

 lengthened, terminating in a subacute summit. Whorls of 

 the spire 7, nearly flat, covered with very regular longitu- 

 dinal striae ; suture superficial. Aperture oval, oblique ; colu- 

 mella vertical, straight, very obliquely truncate in the young, 

 continuous with the basal margin in the adult stage. Peris- 

 tome simple, acute, the margins united by a thin callous. 



"Jaw thin, arcuate, finely and densely plicate vertically. 

 Radula with the central tooth very small, obtusely tricuspid ; 

 laterals with the middle eusp long and subacute, the side 

 cusps short, subequal, and rounded ; marginal teeth tricuspid, 

 short, with the middle cusp short, rounded, and the side 

 cusps small and subacute. Formula 19, 15, 1, 15, 19." 

 (Girard). PL 62, fig. 19. 



Type B. lotophaga Morelet. Distribution, Prince Island, 

 in the Gulf of Guinea. 



This group is chiefly characterized by the smooth early 

 whorls, subobsolete columellar truncation, and vertically en- 

 graved surface of the shell, which has a somewhat pointed 

 apex, not obtusely rounded as in Pseudoglessula, Homorus 

 and Subulona. The lateral and marginal teeth of the radula 

 are all tricuspid, as in Homorus. 



Bocageia holds such a relation to Trichodina as Metachatina 

 kraussi to Cochlitoma. It should probably be ranked as a 

 subgenus of Trichodina rather than a distinct genus. The 

 differential characters being assumed only in the fully ma- 

 ture stage, cannot be of long standing. 



B. lotophaga was placed by Dohrn in his genus Strepto- 

 stele; but he expressly states that he had not seen it, but 

 had collected all the other species which he includes in the 

 group. 



11. T. LOTOPHAGA (Morelet) . PI. 56, figs. 18, 19, 20. 



Shell imperf or ate, fusiform, very closely marked with im- 



