1910.] NATURAL SCIENCES OF PHILADELPHIA. 129 



Length 12.2, diam. 3.4 mm.; whorls 13^. 



Station 6, about half way up the northern slope of a long ridge 

 which projects into Cave Creek Valley from the western border. 



Fifty-three specimens were taken from a single small colony. The 

 frozen ground did not encourage a thorough investigation. Out of 

 20 opened, 17 have three internal lamellae and three have only one, 

 the axial. 



Holospira chiricahuana optima n. subsp. PI. XIV, figs. 13-15. 



The shell is larger and perceptibly more slowly tapering than H. 

 chiricahuana, with more whorls, and only one internal lamella, the 

 axial, in 20 specimens opened. 



Station 5, at the base of the north slope of the ridge mentioned 

 above, close to the stream, under stones. The larger size of the shells 

 might be thought due to the more humid and shaded situation than that 

 inhabited by the typical form, were it not that Holospira prefers hot 

 and arid places and does not exist at all in damp situations. A 

 single colony found. About 75 shells were taken. Thirty-five of 

 them, unselected, measure as follows: 



Whorls. Length. Diam. Whorls. 



14f 13 3.5 13+ 



13| 13 3.5 12f 



13f 13 3.3 13+ 



14+ 13 3.3 13+, 



13+ 13 3.4 13+ 



•2 



1 



13f 13 3.2 13 

 13f 12.9 3.6 12f 

 14 12.8 3.5 13+ 



14+, 12.7 3.3 13+, 



14+ 12.7 3.3 13 



14 12.6 3.4 13*, 



14 12.5 3.5 13+, 



14 12.1 3.25 13 



14+ 12 3.7 12+, 



13i 12 3.3 13+ 



13+ 11.3 3.5 12+ 



13f 11.2 3.3 13i 

 13 



9 



