50 



BYTHINELLA, 



8. BYTHINELLA BINNEYI, Tryon. 

 Plate 16, fig. 8. 



Shell minute, elongated, whorls four to five, 

 apex somewhat obtuse; aperture ovate or 

 nearly suborbicular, both margins rounded ; 

 umbilicus very small. Color light horn, trans- 

 lucent. 



Alt. 3, diam. 1*6 mill. 



Bolinas, California. 



A narrow, smaller, more elongate and more 

 fragile form than the preceding. 



9. BYTHINELLA SEEMANI, Frauenfeld. 

 Plate 16, fig. 9. 



Shell elongate, very narrow, whorls five and 

 a half, convex ; aperture very small, oval ; 

 umbilicus narrow. Greyish-green, translucent. 



Alt. 4, diam. 1*8 mill. 



Durango, N. W. Mexico. 



Narrower than the preceding species. 

 (31) 



