66 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 
tomosing on the first half whorl, then very fine, forwardly-descend- 
ing threads over them, about as in S. hachitana. 
Height 15.3, diam. 26.5mm.; barely 5 whorls. Station 332. Type. 
bs. De 2h“ pewhorls,. Statiam. las. 
Sa ae ‘Station 153. 
i sini ** 42 whorls. Station 153. 
Genitalia (Plate IV, fig. 5) of the hachitana type, but character- 
ized by the much greater length of all of the male organs, which 
are decidedly longer than in S. h. flora, which has a shell at least 
as large as S. mustang. 
The penis is slender, having a sheath which is thick and muscular 
near the base. Its papilla is about two-thirds the length of penis, 
tapering and slender. The flagellum is unusually long; beyond 
the flagellum the vas deferens is somewhat enlarged, as in the 
related forms. The lengths of the organs are as follows: 
Penis 15.5 mm., Penial retractor 11.5 mm., Penis-papilla 10.5 
mm., Epiphallus 8.0 mm., Flagellum 2.0 mm., Vagina 13.5 mm., 
Museum No. 44048. Station 286. 
The jaw has 6 strong ribs. 
Though not much differentiated from S. hachitana in the shell, 
this form appears to be specifically distinct by the genitalia. The 
penis is about three times as long as in S. cotis, while the epiphallus 
is about the same as in that species. 
Common throughout the Mustang range. It was taken alive 
in abundance at Stations 1538, 155, 156 (1918) and Station 332 
(1919). At Station 336 (1919) only a few fossil examples were 
found. Fossil or ‘‘subfossil”’ shells were abundant at Station 153 
(1918). These shells are rather small, between 19 and 22 mm. in 
diameter, with 4 to 42 whorls. 
A few beautiful albino shells were taken at Station 284. 
Sonorella cotis Pils. & Ferr. Plate I, figs. 5, 6; plate IV, figs. 3, 9. 
Nautilus vol. 33, July, 1919, p. 20. 
Whetstone Range. Type 130994 from Station 3 (1914). 
The typical small form only was taken in 1914, the type locality 
being station 3 (1914), a mile up from the Ranger Station. The 
diameter is from 20 to 22mm. _ In the genitalia (Plate IV, fig. 9, para- 
type) this form resembles S. sabinoensis occidentalis. The penis is 
small, slender, becoming abruptly swollen near the base, the swollen 
part containing several large pilasters. The papilla is very slender, 
with slight traces of annulation. Vas deferens is enlarged in the 
lower part, as in S. walkeri. The organs measure: 
Penis. or eee .4.8 mm. Flagelliim . .2c.).40 0.5 mm. 
Penis- papilla eeieee Bier te Vagina: ieee 103539 
Bpiphallass< 22h oe. Bue Museum No....... 119038. 
