326 OCHRODERMA. 



Pleurocera, the lip-edge at this stage toeing retracted above 

 and produced below, as shown in pi. 47, fig. 23. The shell is 

 usually more solid than that of Leptinaria, the whorls less 

 convex, and the cuticle darker. There is usually a tendency 

 to form an entering ridge or low, wide, callous lamella within 

 the outer wall of the aperture. The dentition seems to be 

 essentially that of Leptinaria. Some of the species have 

 been placed in Tornatellina, a genus differing greatly in den- 

 tition. Mr. Ancey has referred Stenogym Carolines Martens 

 to Ochroderma. I have not seen that species, and have given 

 it temporary place in Prosopeas (p. 19). 



The distribution of Ochroderma is at present inexplicable, 

 but I find no sufficient character to justify generic separa- 

 tion of the American species from the type of the Caroline 

 Islands. 



I owe to Prof. H. M. Gwatkin the opportunity of figuring 

 the radula of 0. gigas (pi. 51, fig. 6). It has about 37, 13, 

 1, 13, 37 teeth. The central tooth is excessively small, with 

 a tiny cusp; laterals tricuspid, of the usual Stenogyroid 

 shape. The marginals are tricuspid, becoming irregular to- 

 wards the outer edge. The middle cusp is wide and short, 

 the side cusps very small, subobsolete or sometimes obsolete. 



In 0. martensi (pi. 51, fig. 11, from a co-type) there are 

 25, 8, 1, 8, 25 teeth. The central is larger than in 0. gigas, 

 unicuspid. Laterals of the usual tricuspid type. The mar- 

 ginal teeth are also tricuspid, the cusps small and subequal. 

 The jaw is low, densely stria te vertically, the strise subregular, 

 and more like fine plaits near the lower edge. 



Section Ochroderma s. str. Shell large and heavy ; central 

 tooth very narrow; median cusp of the marginal teeth wide, 

 the side cusps subobsolete. 



1. 0. GIGAS (Martens). PI. 47, figs. 13, 14. 



Shell obesely turrite, glossy, irregularly striatulate, buff; 

 whorls 6 to 7, nearly flat, obliquely finely plicate below the 

 impressed, brownish suture ; last whorl gradually tapering to 

 the base, imperf orate. Aperture about two-fifths the shell 's 

 length, vertical, sinuate-piriform, acutely angular above, the 

 right margin unexpanded, thin, columellar margin widely ap- 



