144 PROCEEDINGS OF THE ACADEMY OF [Feb., 
callus at its inner end (weaker or wanting in dalliana). The parietal 
lamellz are substantially alike in the two species. For comparison 
we reproduce here the type figure of B. bilamellata (fig. 36 B). 
Subgenus CHA NAXIS Pils. and Ferr. 
Bifidaria tuba Pilsbry and Ferriss. 
A few examples were taken by Mort Wien about half a mile from 
Dos Cabezas Cave, where it occurred with Holospira. This extends 
the known range of the species eastward. 
Genus VERTIGO Miller. 
Vertigo is a distinctly boreal element, confined in the Chiricahuas, 
so far as our observations show, to high levels. The species are iden- 
tical with alpine forms of Colorado and Utah. 
Vertigo columbiana utahensis Sterki. 
Head of Cave Creek, 8,000 feet, one example. 
Vertigo milium Gld. 
Head of Pine Canyon, one specimen. 
Vertigo modesta parietalis Anc. 
Head of Cave Creek, 8,000 feet; Long Park. 
Vertigo coloradoensis basidens Pils. and Van. 
Rustler’s Park. 
SUCCINEID 2A. 
Sucoinea avara Say. 
Chiricahua Mountains: Cave Creek Canyon on the slope below the 
cave and at Station 6. 
BASOMMATOPHORA. 
No fresh-water snails were taken in the streams of the Chiricahuas, 
but Pilsbry found two species in the c/énega about midway between 
the Chiricahua and the Peloncillo or Stein’s Peak ranges: Lymnea 
cockerelli Pils. and Ferr. and Physa virgata Gld. Both are widely if 
sparsely distributed in Arizona and New Mexico. 
It is said that sometimes blind fish are washed out of the swollen 
springs in the ciénega when the snow melts on the mountains. 
PELECYPODA. 
Pisidium abditum huachucanum Pils. 
Spring branch, head of Rucker Canyon, many young specimens 
only; Box in Rucker Canyon. 
a tia 
