AMERICAN SPECIES OP VERTIGO. 131 



F.-W. shells of N. A. i, 1869, p. 238; Terr. Moll, v, p. 201; 

 Man. Amer. L. Sh., 1885, p. 172, f. 163. Vertigo modesta 

 corpulent a (Morse), PILSBRY & VANATTA, Proc. A. N. S. 

 Phila. 1900, p. 601, pi. 23, f. 7. HENDERSON, Univ. of Colo- 

 rado Studies iv, p. 172 (Colorado: Los Pinos Agency, Inger- 

 sollj Center and Delta counties, CklL). 



Decidedly more obese than V. modesta, of only about 4% 

 whorls. The crest behind the lip is distinct, and the four 

 teeth are short, the lower palatal being tubercular or very 

 short. Usual length 2.2, diam. 1.35 mm., to 2.45 x 1.4 mm. 

 A photographic copy of Morse's figure is given on page 124, 

 fig. 10. 



It is not known whether corpidenta occurs as a pure race. 

 In a few small lots examined there are no parietalis, but all 

 of the large lots available containing corpulenta, have 

 parietalis also. 



25d. Vertigo modesta insculpta n. subsp. PL 10, figs. 12, 13. 



The shell is similar to V. m. parietalis in teeth, but differs 

 by the distinct, rather sharp striation of the penult and ante- 

 penult whorls, sometimes also the last. Length 2.6, diam. 

 1.35 mm. 



Arizona: Bill Williams Mt., Coconino Co., Ferriss; Santa 

 Catalina Mts. in many localities, 9000-9500 ft., the types from 

 Mt. Lemon, 9500 ft. ; White Mts., Apache Co. ; Blue River and 

 Rim of Blue Mts., Graham Co.; Chiricahua Mts., at head of 

 Cave Creek and Long Park, about 8000 ft., Ferriss. New 

 Mexico : Black Range, in the forest zone, Ferriss & Pilsbry. 



It differs from the southern form of V. concinnula by the 

 larger size and typically shorter palatal folds, yet there is a 

 certain amount of intergradation in both characters. In the 

 Black Range, especially, there are often short specimens, down 

 to 2.25 mm. long. Each of the ranges which ascends into 

 the zone of coniferous forest appears to have either a smaller 

 (concinnula) or a larger (inscidpta) stock, in the average 

 distinguishable, though individuals are often perplexing. The 

 distinction is rather finely drawn, yet such as it is, has been 

 reached after examining some thousands of fresh shells. 



