76 THE NAUTILUS. 



Fluminicola minutissima n. sp. Plate IX, fig. 1. 



The shell is perforate, obliquely globose, thin, smooth, olivaceous 

 yellowish, composed of three rapidly enlarging whorls, which are 

 convex, and separated by an impressed suture, which becomes very 

 deep in the last half-whorl. The spire is very short, the summit 

 obtuse, the first whorl being nearly flat. The last whorl enlarges 

 rapidly, and is -well rounded peripherally, less so below ; its last half 

 descends rapidly. The aperture is quite oblique, nearly circular, but 

 is angular above. The outer lip is thin, distinctly retracted at the 

 upper insertion ; the slightly concave columella is very strongly 

 calloused within, flattened on the face. Below the umbilical per- 

 foration there is a narrow, crescentic, slightly excavated area, 

 bounded outwardly by a low angle. 



Alt. 1.5, diam. 1.75 mm. 



Price Valley, Weiser Canyon, Washington Co., Idaho. Types 

 no. 94273 A. N. S. P., collected by the Rev. E. H. Ashmun. 



This species is smaller than any other of the genus, and is further 

 distinguished by its very short spire and the rapid descent of the last 

 half whorl. The columellar callus is unusually heavy for so small 

 a shell. 



SHELLS COLLECTED IN NORTHEASTERN MEXICO. 



BY A. A. HINKLEY. 



BULIMULIDjE. 



Oxystyla princeps Brod. Tampico and Valles. Only dead 

 specimens secured. 



UROCOPTID.E. 



Macroceramus mexicanus Martens. El Abra. 

 Holospira hinkleyi Pils. El Abra, on the mountain side with 

 Opeas. 



PUPILLIDJS. 



Strobilops hubbardi A. D. Brown. Tampico, scarce in drift. 



Pupoides marginatus Say. Tampico, drift. 



Bifidaria contracta Say. Tampico, drift, the most abundant 

 species. 



Bifidaria pellucida Pfr., var. hordeacella Pils. Tampico, drift, 

 almost as numerous as B. contracta. 



