78 PROCEEDINGS OF THE ACADEMY OF [Feb., 
group further differs from the O. strigosa group in possessing radially 
costulate apical whorls. 
Snails of both of these groups live immured in the shaded rocks of 
the mountain ‘slides,’ composed of broken rock or spawls tumbled 
down from the peaks above. O. clappz lives from 5,000 to 7,000 feet, 
and OQ. barbata from 7,000 to 10,000 feet above the sea. The dead 
shells are seldom found upon the surface. Oreohelix chiricahuana, in 
the same mountain range, requires but little covering, and is found in 
dry situations, often with but a single leaf or a small spawl for pro- 
tection. It agrees with the Oreohelices of other regions in having a 
very thin cuticle, often wanting. Dead agavas and yuccas furnish 
a home for these, the Holospiras and Succinea avara; but O. barbata 
and O. clappi, the Ashmunellas and Sonorellas require an atmosphere 
with more moisture, and dwell from one to two feet below the surface. 
He who finds must dig. ¢ 
All Chiricahuan Oreohelices are confined to that range, and none 
of them are closely related to species found elsewhere. All are con- 
spicuously variable in each colony and in different colonies, nearly 
every one of which shows a degree of racial differentiation, so that 
one acquainted with these shells, even as imperfectly known at 
present, could locate himself if lost in the Chiricahuas by digging for 
Oreohelices ! 
No adequate discussion of these shells can be entered into without 
more and better illustrations than are possible to us at this time, and 
long series of measurements. We.have merely indicated briefly the 
salient features of each colony. 
The Oreohelix clappi series. 
The group of local races which for taxonomic purposes is considered 
to compose the species O. clappi comprises about a dozen colonies, 
scattered over the range for a distance of about 44 miles. The 
relationships of the snails of these colonies may be expressed dia- 
eramatically thus: 
Emigrans—Onion Creek—Reed’s Mt.—type——-—Cataracta 
Horseshoe—Shake Gulch—Rucker Box 
The forms toward the left in this diagram are successively more 
roughly sculptured, toward the right they are smoother. The type 
happened to be of intermediate character, and near the central point 
of the range of the species. The upper line forms a variation-series 
extending from Big Emigrant Canyon (emigrans) to the Falls of 
