38 THE NAUTILUS. 



which, however, become much weaker on the base; surface pol- 

 ished and lustrous, especially on the base. Embryonic whorls, 

 where not eroded, at first rather rudely radially wrinkled, but, 

 at least after the first half turn, strongly, coarsely papillose, as well. 

 Spire low, almost straight sided except toward the summit; 

 sutures well impressed. Whorls usually 5| to 6. Body whorl 

 subangulate at the shoulder, but becoming more rounded as the 

 aperture is approached; slightly decending and rather abruptly 

 constricted just back of the peristome, the base moderately 

 swollen and rounded. Lip whitish or stained a very light 

 brown; thickened and reflexed but not very wide; obscurely 

 angled and narrowed below the pillar, which is somewhat re- 

 flexed over the narrow but permeable umbilicus; lip often 

 showing a slight extra thickening on the base, but aperture 

 otherwise without denticles save for an occasional specimen 

 showing the merest trace of a parietal tooth. Color of body 

 whorl fairly near tawny olive, deepening to snuff brown or 

 Saccardo's umber on the earlier whorls. 

 Measurements: 



Type. Paratype. Paratype. Paratype. 



mm. mm. mm. mm. 



Greater diameter 14.0 13.5 13.3 12.7 



Lesser diameter 12.0 11.4 11.3 10.6 



Height 9.0 8.2 8.7 8.0 



Diameter of umbilicus 1.0 1.1 1.0 0.8 



Number of whorls 6 b\ 5| 5| 



Type: Cat. No. 5089 of the writer's collection. Paratypes 

 have been deposited in the collections of the California Academy 

 of Sciences, Academy of Natural Sciences of Philadelphia, and 

 Leland Stanford Junior University, as well as the private collec- 

 tion of Allyn G. Smith. 



Type Locality: La Moine, Shasta County, California; Allyn 

 G. Smith, August 1921; 25 adult specimens. 



Remarks: Although I have been gathering material of Poly- 

 gyra columbiana for several years, with a view to possible mono- 

 graphic treatment of the species, I am still uncertain how far it 

 will be wise to go in giving taxonomic recognition to the in- 

 numerable weakly differentiated races of this widespread snail. 



