1910.] NATURAL SCIENCES OF PHILADELPHIA. 103 
Genitalia (pl. X, fig. 9) not materially differing from A. p. albicauda. 
The swollen basal portion of the penis is less than half the total length. 
The penial retractor is less than one millimeter long. 
Ashmunella fissidens Pils. 
- Proc. A. N.S. Phila., 1905, p. 248. 
This species was described from “dead’”’ and discolored specimens, 
thought to be from Cave Creek Canyon, collected by one of us (Mr. 
Ferriss) in the course of a flying trip through the mountains in the 
winter of 1904. In 1906 we collected extensively in Cave Creek; 
a year later Messrs. Ferriss and Daniels did additional work there, but 
nothing was seen of A. fissidens. The location of the type colony, 
therefore, remains uncertain. It is likely that the shells were picked 
up in White Tail Canyon, also hurriedly traversed in 1904. While 
the prevalent form in White Tail differs from fisstdens in several 
respects, yet near the head of the canyon some exactly similar shells 
were found by us in 1906. A lot from near the head of the left branch 
(going up) (near Jim Artel’s old camp) is typical fissidens; and we 
suggest that this be regarded as the type locality in case true fissidens 
is not hereafter found in Cave Creek. 
’ In these shells the lip is not produced forward in an angle near the 
upper insertion, and the upper angle is not filled with a callus; the lip 
is narrow with rounded face; there is no upper branch developed on 
the parietal wall, unless very weakly in some old shells; there are 
fully 6 whorls; the young develop only a weak lip-rib at resting 
stages. 
Certain forms from much further south, in Shake Gulch, the foot of 
Bonito Canyon and Limestone Mountain, seem to be referable to 
A. fissidens; but they are less angular, becoming rounded behind the 
lip, and the umbilicus is decidedly smaller. More material is needed 
to fix their status. 
Ashmunella fissidens albicauda n. subsp. Fig. 19. 
The upper end of the parietal wall stands more or less free and the 
lip, near its upper insertion, runs forward in an angle; the posterior 
angle of the aperture is heavily calloused, and the parietal tooth is 
usually V-shaped by development of a weak upper branch. The 
young shells form a very thick and heavy callus within the lip at 
resting stages (fig. 19D). 
Adult shells are invariably acutely angular in front, the angle 
weakening and almost disappearing on the latter part of the whorl. 
Behind the aperture the striation is stronger and sometimes amounts 
