STROBILOPS. 61 



stop at the periphery, but a few on the last half whori continue 

 over the base ; they reappear in the umbilicus. The aperture 

 is lunate, the outer and basal margins about equally curved, 

 expanded a little, strongly thickened within. The parietal 

 lamella is strong and penetrates inward almost an entire whorl. 

 The infraparietal lamella emerges and is broad and united 

 with the parietal by a callus at the end ; it penetrates as far as 

 the parietal. Under a high power the edges of both lamellaa 

 show very indistinct swellings or nodes, which are slightly 

 roughened. The inner end of the parietal has more distinct 

 serration. There is no interparietal lamella. Within the base, 

 slightly more than a half whorl behind the aperture, are two 

 basal folds, corresponding to those numbered 1 and 2 in the 

 diagram of strobilopsid teeth (see p. 2, fig. 1)., the inner one 

 is lower than the strong outer one, and only about half as long 

 (fig. 5). No columellar lamella seen. 



Height 2 mm., diam. 2.7 mm. ; umbilicus 1 mm. Type, figs. 

 1-3. 



Height 1.9 mm., diam. 2.4 mm. Figs. 6, 7. 



Heights 2.1 mm., diam. 2.8 mm. 



Grand Cayman Island, about midway between North Sound 

 and Eed Bay. Type 150861 A. N. S. P. (Pilsbry). 



StroMlops wenziana Pilsbry, Proc. A. N, S. Phila., vol. 82, 

 p. 238, pi. 19, figs. 1-7, July 18, 1930. 



This species can be compared only with Strohilops salvini 

 (Tristram) of the mountain forests of Vera Paz, Guatemala, 

 which has a similarly wide umbilicus. I have not seen that 

 species, but it is said to be angular peripherally, of 51/^ whorls, 

 with only one lamella emerging on the parietal wall (the in- 

 fraparietal being shorter) . The shape of the aperture is quite 

 different, according to the figure of the type given by von 

 Martens. Unfortunately, the internal armature of S. salvini 

 has not been fully described. I have seen all other American 

 species of the genus, and none is at all like S. wenziana. 



This is the only West Indian Strohilops of the conic group. 

 Its presence on Grand Cayman is the most surprising occur- 

 rence in the West Indian land snail fauna which has turned 



