108 AMERICAN SPECIES OF VERTIGO. 



It appears rather closely related to V. tridentata from which 

 it differs chiefly by the narrower aperture, further contracted 

 by a much stronger palatal callus. Description and figure 

 from the type, no. 85574 A. N. S. P. Other specimens were 

 taken by S. Brown in leaf mould, Paynter's Vale, near the type 

 locality; but while doubtless recent they are bleached. It is 

 far less abundant than V. numellata in the same places. 



( West Coast species of the V. pygmcea group ) . 

 18. VERTIGO COLUMBIANA Sterki. PL 9, figs. 12, 13. 



Shell minute, cylindric-oval, perforate, thin, pale corneous- 

 brown (grayish cream-buff), somewhat transparent, glossy and 

 weakly striatulate. Whorls nearly 5, convex, the last ex- 

 panded in a very low crest very close to the lip, not noticeably 

 constricted in front of the crest. Aperture truncate-oval, 

 4-toothed, the peristome thin, hardly expanded; parietal la- 

 mella short and high, columellar a little smaller, lower palatal 

 a rather short fold, about twice as long as the upper palatal 

 which is smaller, shorter, almost tuberculif orm ; all the teeth 

 are white, and the palatals show through the outside wall. 



Length 1.9, diam. 1.1 mm. (type). 



Length 2.05, diam. 1.2 mm. 



Vancouver Island, George W. Taylor, type loc. (no. 68881 

 A. N. S.). Washington: Olympia and Tacoma, H. Hemphill; 

 Seattle, Hemphill, P. B. Randolph; L. Quiniault, Chehalis 

 Co., S. S. Berry. Oregon: Douglas county, F. H. Andrus. 

 St. Paul Island, Bering Sea, Dall. 



Vertigo columbiana STERKI, Nautilus, vi, 1892, p. 5 (name 

 only). PILSBRY & VANATTA, Proc. A. N. S. Phila., 1900, p. 

 602, pi. 23, fig. 11. DALL, Alaska Land and Fresh Water 

 Mollusks, 1905, p. 30. Pupa columbiana, STERKI, PILSBRY, 

 Nautilus xi, 1898, p. 119 ; Class. Cat., p. 21, no. 212. 



The surface is decidedly less striate than in V. coloradensis, 

 V. concinnula or V. gouldii. It is like that of V. ventricosa. 

 There is no angular lamella and no basal fold in any of the 

 specimens; but only a few have been seen from each locality. 

 The single specimen from Olympia is very short, 1.4 x 1 mm. 



