STREPTAX1S. 



S. THOMASI, Pfr. PL 13, tig. 48. 



Thin, striulate, somewhat shining; umbilicus moderate, per- 

 spective ; lip simple ; yellowish white. Diam., 7 '5 mill. 



Marmato, N. Granada. 



S. TROCHILIONEIDES, Orb. PL 13, figs. 49-51 ; PL 27, tigs. 5-7. 



Shell thinly striulate, shining, diaphanous, white ; whorls 6, 

 .somewhat flattened; umbilicus moderate; aperture subvertical, 

 the lip simple, its extremities approaching. Length, 4'5 mill. 



Bolivia. 



H. spirillus, Gould (figs. 5-7), from Lima, Peru, is a synonym. 



-> 



S. AMMONOCERAS, Pfeiffer. PL 13, fig. 52. 



Much depressed, arcuately striate, thin, pellucid, shining; 

 light corneous ; spire minute, subimmersed, suture profound ; 

 whorls about 4, rapidly increasing, the last laterally flattened, 

 with obsoletely angulated periphery ; aperture wide, oblique, lip 

 simple ; umbilicus wide. Diarn., 4'5 mill. 



Santa Ana, N. Granada; also island of 



Grenada, W. I. (Bland). 



S. MOYOBAMBENSIS, Moricand. PL 13, figs. 55, 56. 



Shell depressed, rather solid, closely rugosely striated, with a 

 few impressed concentric lines ; whorls 4-4J, the last inflated, 

 with well-impressed suture ; aperture large, subcircular, pearly, 

 the lip simple ; olive corneous. Diam., 31 mill. 



Moyobamba, Peru. 

 S. ORBICULA, Orb. PL 13, figs. 35-37. 



Broadly umbilicated, nearly discoid, finely striated, diaphanous, 

 shining, grayish yellow ; whorls 7-8 ; umbilicus broad ; lip simple, 

 sharp. Diam., 10 mill. 



Bolivia. 



S. AMMONIFORMIS, Orb. PL 13, figs. 43-45. Magn. f. 



Widely umbilicated, orbicularly concave, depressed, thin, 

 diaphanous, grayish white, nearly smooth ; whorls 5, the last 

 obliquely dilated; lip simple, sharp, recurved above. 

 Diam., 14 mill. 



Bolivia. 

 5 



