bw 
1910.] NATURAL SCIENCES OF PHILADELPHIA, 55 
Key to Chiricahuan Species of Sonorella. 
a.—Penis comparatively short, very much less than the diameter of 
the shell, and about + to 4 the length of spermatheca and its 
duct (Group of S. hachitana). 
b.—Penis-papilla annulate, the free end more or less pointed; 
epiphallus less than half the diameter of shell; whorls 43 
to 54. 
c.—Flagellum wanting or vestigeal; diameter of shell 15.5 to 
Pra RUNMIM Dy eee Miter OI. as Se Psu en eee acevo apenan ee eaat S. optata. 
c'.—Flagellum distinct but minute; diameter of shell 18 to 
725) 0d TaN OT CARE Ce ait REED aE RA Ra eS S. bicipitis. 
b'.—Penis-papilla plain, cylindric with obtuse end; epiphallus 
about half the diam. of shell; penis larger; whorls about 44. 
c.—Umbilicus contained about 54 times in diameter of the 
shell, which is depressed, 15 to 18 mm. in diameter. 
S. bowiensis. 
c'.—Umbilicus contained about 10 times in diameter of shell, 
which is subglobose, 13.5 to 20 mm. in diameter. 
S. binneyt. 
a'.—Penis very large, its length exceeding the diameter of the shell, 
and not differmg much from the length of spermatheca and 
duct; penis-papilla and vagina very long (Group of S. virilis). 
b.—Shell moderately solid, larger. 
c.—Diameter of shell 16 to 21 mm......0...0... cee S. virilis. 
c!.—Diameter of shell 18 to 25 mm. ; more depressed. S. v. leucura. 
b!.—Shell thin, smaller, diameter 12 to 15 mm.................. S. micra. 
Group of Sonorella hachitana. 
Sonorella bicipitis n.sp. Pl. I, figs. 1-5. 
Shell of the group of S. hachitana, the umbilicus about one-seventh ° 
the total diameter, and one-third covered by the dilated columellar 
lip; brown, fading to white around the umbilicus, encircled above the 
periphery with a dark chestnut band bordered above and below with 
white bands of about the same width; the brown band visible on about 
two whorls of the spire, the upper white band visible also on the 
penultimate whorl. Whorls 42 to 5, rather slowly increasing at first, 
the penultimate and last whorls rapidly widening. Surface nearly 
smooth to the eye, glossy. Embryonic shell consisting of 14 whorls. 
The first half whorl has distinct radial ripples; the next whorl has 
close, fine wrinkles in the direction of growth-lines, and interrupted 
by delicate, spirally descending threads. The third whorl shows 
some very sparse punctation. Later whorls are marked with fine 
growth-ripples, and usually show, under a strong lens, some exces- 
sively faint spiral lines above the periphery. The last whorl descends 
