14 



ANCYLUS CRASSUS, Hald, 



Plate 1.— Fig. 8. 

 A. testa magna, lata, ovata, solidula, elevata. 



DESCRIPTION. 



Shell coarse, somewhat ponderous, wide, 

 ovate, elevated; lines of growth conspicuous; 

 apex eroded, placed far back: anterior and 

 lateral slopes convex, posterior slope steep and 

 rectilinear. 



Color opake chesnut-brown. 



Dimensions. Long. 8, lat. 6.25, elev. 3 mill. 



Geographical Distribution. Brought from 

 Oregon by Mr. Nuttall. 



OBSERVATIONS. 



Distinguished by its opacity, and thick texture, 

 all the preceding species being more or less 

 translucent and delicate. 



