1910.] NATURAL SCIENCES OF PHILADELPHIA. 105 
shorter than in A. p. emigrans or A. duplicidens, but this may be an 
individual character. 
A. f. albicauda is found in White Tail Canyon almost everywhere 
on the southern side, but not on the opposite slope of the canyon. Speci- 
mens were taken at Stations 1 to 5, 9, 12, 14, on the south side of the 
Box Canyon and on the south side below Indian Creek, ranging from 
about 20 feet above the creek bed (at the last place) to about 7,500 
feet elevation on the rim southward, where indeed it was taken at 
Station 3, which les across the acute divide and on the Pinery side. 
Not one single specimen was found on the north side of the canyon, 
where A. lepiderma replaces it, coming down to the bottom of the 
canyon. 
The range of A. fissidens in the Pinery and Pinery Canyon is un- 
known. The great Pinery Valley lay before us in splendid panorama 
from the ridge south of White Tail Canyon and again from the ridge 
north of Barfoot Park. Probably its ravines are inhabited by fissidens 
and perhaps forms connecting that with A. proxima. It may be noted 
that the large Sonorella of White Tail Canyon is a race of S. virilis, 
of Barfoot Park, etc. 
At all stations in White Tail Canyon where many shells were taken, 
the same variations in height of spire noted under A. duplicidens were 
noticed, Otherwise there is variation in the size of the outer lip-tooth 
and especially in that of the inner tubercle of the basal tooth. The 
parietal tooth may be either straight at its axial end or abruptly 
curved inward, and, when turned inward, a low ridge usually runs to 
the outer end of the lip, making the parietal tooth V-shaped. 
Ashmunella fissidens pomeroyi n. subsp. Fig. 20. 
In Hand’s Pass, head of Jhu Canyon, Ferriss and Pomeroy collected 
2 
eS 
‘eau a 
SS IN NY 
SS 
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DB 
Fig. 20.—Ashmunella j. pomeroyi P. and F., Hand’s 
