236 PROCEEDINGS OF THE ACADEMY OF [Mch., 



Specimens from Canyon Diablo, near Rowe, New Mexico (PI. XIII, 

 figs. 35, 36, 37), are exactly like those from Las Vegas Hot Springs. 

 Alt. S 6.8 6.6 6.4 6.3 mm. 



Diam. 14 12.8 12.3 12.3 12 



^Vllorls 5^ 5J 51 5i 5 " 



Ashmunella thomsoniana porteree Pil?. and Ckll. PL XIII, figs. 39-46. 



AshmnneUa thomsoniayia porterce Pils. and Ckll., Nautilus, XIII, p. 49, Sep- 

 tember, 1899; Cockerell and Cooper, Nautilus, XV, p. 109, February, 

 1902, with mut. alba, p. 110; Murdoch, Jour, of Malac, VIII, p. 82, PI. 

 7, fig. 8 (genitalia) ; Pilsbry, Proc. Acad. Nat. Sci. Phila., 1900, p. 559, 

 footnote 4, PI. 21, fig. 6 (palhal complex). 



A. i. cooperce Ckll., Nautilus, XVII, p. 36, July, 1903 (Pecos). 



Shell larger than tliomsoniana , light brown, glossy, a little translucent, 

 with distinct growth-wrinkles and fine incised spiral lines. Whorls 5^ 

 to 6, convex, the last deeply constricted behind the lip, swollen behind 

 the constriction. Lip brown-tinted above. Parietal lamJna mode- 

 rately developed. Outer lip-tooth long and concave. Basal tooth 

 bifid, the inner denticle smaller, sometimes reduced to a low callous. 

 Umbilicus rather broadly open, exposing the penultimate whorl more 

 than in thomsoniana. 



Type locality. Upper Sapcllo Canyon, Beulah, New Mexico (PI. 

 XIII, figs. 39-42, 46, Miss Wilmatte Porter, Dr. H. Skinner and others). 



Twenty-two specimens collected by Dr. Skinner measure as follows : 



Prof. Cockerell and Miss Cooper measured 40 specimens of porterce 

 from Beulah: 



2 specimens are 14 mm. diam. 

 12 " " 14+ " " 

 17 " " 15 



6 " " 15+ " 



3 " " 16 



There is no appreciable difference in the comparative altitude among 

 the specimens I have seen. 



