AMERICAN SPECIES OP VERTIGO. 



Vertigo rugosula STERKI, Proc. A. N. S. Phila. 1890, p. 34 ; 

 Nautilus iv, p. 39, pi. 1, f. 3; reprinted by Binney, Fourth 

 Supplement T. M. vol. v, in Bull. Mus. Comp. Zool. vol. 22, 

 no. 4, 1892, p. 201, figure. WHEELER, Nautilus xxv, p. 124 

 (Monte Sano, Madison Co., Ala.). 



Besides the smaller size, darker color, and characteristic 

 striation, which is much more regular and stronger than in 

 V. ovata,, this species differs by the shape of the angular 

 lamella, which is rather long, low in front, rising inwardly. 

 It emerges about as far as the parietal lamella, which is strong 

 and quite long. The infraparietal lamella is a very small 

 tubercle, as a rule, sometimes scarcely or not perceptible. The 

 inner end of the upper palatal fold turns downward. Further 

 differences are given by Dr. Sterki : ' ' The last whorl is rela- 

 tively smaller, the aperture is somewhat less broad ; the crest 

 and impressions over the palatal folds are less marked or 

 wanting; the palatal callus is thin or wanting; the basal fold 

 is situated higher on the columellar margin, in the position 

 of a subcolumellar lamella, while in T 7 . ovata it is basal." 



In profile view there is a slight prominence of the outer 

 lip, at the termination of a shallow depression, but it is far 

 less developed than the "auricle" of V. ovata. 



A topotype received from Dr. Sterki (fig. 3) measures, 

 length 2, diam. 1.2 mm. ; barely 5 whorls. 



Dr. Sterki gave also the locality Fish Camp, Fresno Co., 

 California., H. Hemphill ; I have not seen the specimens but 

 possibly they are what I am calling V. ovata mariposa, a 

 shell which does not have the distinct striation of V. rugosula. 



la. Vertigo rugos-ula oralis Sterki. PI. 8, figs. 5, 6, 7. 



'It is somewhat smaller [than rugosula], ovate, the striation 

 and rugosity of the surface are less marked, and the inferior 

 apertural [infraparietal] lamella is wanting; in turn it has in 

 most examples a lamella at the base (between inferior colu- 

 mellar and inferior palatal) and the callus in the palatal wall 

 is rather strong. The coloration of part of them is somewhat 

 lighter. It cannot be confounded with V. ovata Say, its 

 relations to the type of rugosula being evident, and in addition, 



