1915.] NATURAL SCIENCES OF PHILADELPHIA. 405 
The top of the head is gray, integument elsewhere cream-tinted. 
The median area of the sole is whitish, twice as wide as either side 
area, the latter flesh-tinted. 
The genitalia (Pl. XIII, figs. 2, 10).--Penis very small and slender, 
having a very short, weak basal sheath of a few loose fibres. The 
papilla is coarsely annulated, very slender and long. The penis- 
retractor muscle is inserted on the epiphallus, which is extremely 
slender, not so wide as the vas deferens, but enlarged a trifle where it 
joins the latter. There is no flagellum. Female organs as usual. 
Jaw having four or five unequal ribs, sometimes rather weak 
(Pl. XIII, figs. 6, 6a). 
= Ouriine or SAN Xavier fee FROM WEST, Seu sativa 
STATION IN CEN 
SONORELLA---- 
SANXAVIER Hite 
HELMET P 
Fig. 7—Plan of the Mineral Hills, scale 2 inches to a mile, with sketch of the 
type locality of Sonorella eremita. 
In the genitalia, as well as the shell, this species resembles S. 
papagorum, but it differs by having a smaller penis and by the very 
slender epiphallus, which is actually smaller than the vas deferens 
in several specimens dissected. In S. twmamocensis the penis is 
very much longer. The shell is smaller than S. papagorum, with 
far more strongly developed apical sculpture than in any other species 
of this district. It is also more solid, and, having an aspect of its 
own, is not likely to be confused with any other Sonorella known 
to us. 
The size is quite variable: 
