1910.] NATURAL SCIENCES OF PHILADELPHIA. 83 
line between the two. This is the greenest in color of the group, the 
texture of the cuticle is the most harsh and it is the largest in diameter. 
4, Form From Rucker Canyon.—The sculpture in this form is 
weak, the oblique wrinkles smooth, in part effaced, and lower on the 
base; spiral striation weak or subobsolete, hardly noticeable above. 
Cuticle glossy, persistent, varying from rather bright green or greenish- 
yellow to brownish-olive, the two brown bands distinct. There are 
sometimes two fainter bands, one above, the other on the base. The 
last whorl is only very obtusely angular, the angle, well rounded, usually 
falls less in front than in the Onion Creek lot. The aperture is con- 
spicuously longer than in typical O. clappi; upper margin decidedly 
arched. In old shells the lip-ends approach closely, but are not 
connected as in the typical O. clappi, the callus between them remaining 
thin and transparent. 
Up to 34 whorls the young carry five strong cuticular fringes below, 
one at the periphery and one above. The cuticle in larger shells is 
smooth. 
The largest in 45 measured: 
Alt. 10, diam. 164 mm. 
“cc 10, (as 163 (zs 
caters, 216k) 
nae iy 
‘e 9 oe 154 oe 
This is the handsomest of the group in color and, with the exception 
of O. c. cataracta, the smoothest, the base being polished with somewhat 
of a varnish-like gloss. The last whorl is even more rounded per- 
ipherally than in typical O. clappi. In 1908 it was found in a deep 
gulch, the ‘‘box” of Rucker Canyon, at about 8,000 feet elevation, 
on both sides of the stream in sliding rock, where the atmosphere was 
as moist as the stations on Cave Creek, about 12 miles distant. It is 
a near neighbor with O. barbata, a small form of the latter being plenti- 
ful at the twin caverns in the box, while QO. clappi was found half a 
mile farther down the stream. 
5. SHAKE GuLcH ForM.— 
The shell is sharply angular peripherally, 
the angle becoming obtuse near the lip; whorls flattened above; 
cuticle dull, lusterless, persistent, obscure olive at the base, the upper 
surface with a russet suffusion, peristome black-bordered. There are 
one or two faint bands. The surface is obliquely, rather obtusely, 
wrinkled, the base distinctly striate spirally, growth-lines low, not 
waved. The sculpture of the embryonic shell is very weak, and 
