1923] NATURAL SCIENCES OF PHILADELPHIA 99 
later whorls moderately so, with a well impressed suture. The 
last whorl is flattened laterally, sloping to the base, is contracted 
and very shortly free in front. The small aperture is rounded with 
part of the upper margin straightened. Internally there are one 
to three lamelle. The type having an axial lamella only. 
Length 14.2, diam. 3.7 mm., 14} whorls. Type. 
Sennett eaters ee 3.036" «18 ss 
This species resembles H. cionella and H. chiricahuana. The 
latter has a longer terminal taper, passing imperceptibly into the 
cylindric part. H. cionella is a smaller species with finer sculpture. 
Out of 7 specimens from the type locality opened, 2 have an 
axial lamella only, 4 have axial and basal, and one has axial, basal 
and parietal. Several opened from the other two stations have 
the axial lamella alone. 
The specimens from Station 293 are similar to those from 304, 
the type station; but at 305 the shells are smaller, extremes measur- 
ing: 
Length 11.3, diam. 3.7 mm., 123 whorls. 
73 9.5, (73 3.6 79 103 (73 
A few opened have a axial lamella only. 
Also taken in the Empire Mountains, Station 149 (1918), on the 
north side of a large limestone peak 14 miles northwest of the 
Total Wreck mine. Specimens small, about as at Station 293, 
above; only an axial lamella. 
Holospira whetstonensis arata n. subsp. Text-fig. 16. 
Mustang Mountains, Stations 159 (1918), type loc., and 153 
(1918), both on the eastern dome of the range. Type 131005. 
The shell is smaller, especially shorter than whetstonensis, with 
a shorter neck, but having similar strongly cut riblets, coarser than 
in H, ferrissi; the terminal cone longer than in ferrissi. There is 
an axial lamella lateral in position. 
Length 9.3, diam. 3.5 mm., 114 whorls. Type. 
oi weet Fanos Lopotype. 
ia a3 
a 8.5 me Ps 4 
s 1s soe 2 *.) 12 whorls. Station 153: 
“ec 9.4 a4 3 7 74 103 (a4 “ce ce 
IV. On MicraRIonTA ROWELLI (Newe.) AND M. NEWCOMBI, 0. sp. 
Micrarionta rowelli (Newc.). Plate III, figs. 7 (type), 6. 
Helix rowelli Newcomb, Proc. California Acad. Sci. III, 1865, p. 181. Binney 
and Bland, Land and Fresh-water Shells of N. A., I, p. 185, upper fig. 
326; not the description or lower figure. 
