THE NAUTILUS. 17 



be mistaken. Generally smaller; somewhat elongate in outline, 

 and so is the umbilicus ; the spire is smaller, lower, and the suture 

 less deep ; the peristome is not everted, as in pnlchella, but only 

 slightly expanded. 



Group of V. costata. Ribbed ; peristome with strong lip. 



3. V. costata Mull. Eastern North America to the Mississippi 

 Valley, but less common than pnlchella, though numerous in some 

 localities. 



4. V. albula Sterki. Quebec, Manitoba to British Columbia. 

 Larger than costuta (27-2'8 mill.), whitish, with fine, crowded, 

 membranous ribs ; quite unlike any costata from Europe or North 

 America. Also jaw and radula show differences, and so it was to be 

 regarded as distinct, the more so as it has been found in company 

 with costata at Quebec. 



5. V. gracilicosta Keinli. Utah to Dakota. Differs from costata 

 by the stronger and more oblique ribs on the shell, and small or no 

 membranous appendages on them ; the last whorl and the aperture 

 are more angular at the periphery, and more flattened above ; the 

 color is grayish, and the lip porcelain white, while in costata it is 

 somewhat glassy transparent. 



li. V. pnrvula Sterki. Illinois to Nebraska and Indian Territory. 

 Smaller than costata (diam. 2 mill.), the spire flat, the last whorl not 

 descending. 



Group of V. cyclophorella. Peristome without a lip. 



7. I'. ei/clopJwrella Ancey. Rocky Mountains. Ribs very fine 

 and crowded ; shell thin, grayish or whitish ; last whorl ascending 

 and descending ; aperture transversely elongate ; peristome thin, 

 without a lip ; diam. 27 mill. 



8. V. perspective!, Sterki. Appalachian Mountains, in Tennessee 

 and Alabama ; also in Iowa. Membranous ribs rather fine and 

 crowded; spire low; last whorl descending; peristome continuous 

 without a lip ; shell thin, pale horn to colorless ; diam. 2'0 mill. 



ON THE GENEEIC POSITION OF PATULASTRA ! [PUNCTUM ?] PUGETEN- 



SIS AND PYRAMIDULA? RANDOLPHII, WITH SUGGESTIONS 



FOR A CLASSIFICATION OF AMERICAN ZONITIDJE. 



BY HENRY A. PILSBRY. 



Specimens of the two species named above preserved in alcohol 

 by Mr. Randolph, of Seattle, Washington, and kindly forwarded 

 'These species were described in NAUTILUS for March, 1895, p. l:>o. 



