1915.] NATURAL SCIENCES OF PHILADELPHIA. 381 
whorls of the cone somewhat more sharply striate than the cylindric 
portion, upon which the striz are very fine and close; typically about 
90 fine, close strie on the penultimate whorl. The latter part of 
~ the last whorl is slightly compressed and has slightly coarser, sharper 
strie. The aperture is carried very shortly free, is not calloused 
within, and has a narrowly reflexed lip. Within the latter part of 
the penultimate and first part of the last whorl there is a rather 
stout, obtuse lamella on the axis. No lamelle on the upper or basal 
walls of the cavity. 
Length 12, diam. 4 mm.; 12 whorls. 
Dragoon Mountains, south of Tweed Canyon, the types from 
Station 7, the summit of a limestone ridge separating the head of 
Cataract Gulch from the next canyon opening westward, south 
of Tweed Canyon, No. 112,225, A. N.S. P., collected by Ferriss, 
Pilsbry and Daniels, October, 1910. Also taken at Station 7, and 
Stations 29 to 37 southward from Stations 7 and 8. 
H. millestriata is related to H. campestris, from which it differs by 
having more numerous, finer striz, and by the absence of internal 
lamellz on the parietal and basal walls of the cavity, in a long series 
of shells opened. Its range is separated from that of H. campestris 
by the ridge of eruptive rock which runs from Cochise stronghold 
along the south side of Tweed Canyon westward to the mesa; no 
Holospiras being found on this ridge, so far as we know. The isola- 
tion of the two species seems, therefore, to be complete. The species 
is quite constant in hundreds of shells collected from many colonies, 
as noted below; but in two stations in small hills on the mesa east- 
ward of Middlemarch Canyon there is notable variation. Further 
study should be given to these small forms of the border between 
mountain and plain. In over a hundred shells opened from all the 
colonies, only one has a very weak trace of a superior lamella, all 
others having only a stout axial lamella. 
The type locality, Station 7, is on the divide, a ridge above an 
abandoned mine and cabin. It may be reached by ascending Cata- 
ract Gulch from Tweed Canyon, but much more easily along the 
mountains eastward, as the gulch is rather a neckbreaker. The 
specimens are quite uniform in sculpture. Length up to 12.2 mm., 
and very rarely as short as 9.8 mm., with 10 whorls. (Pl. XV, figs. 
3, 3a, 3b). Out of twenty opened, one has a weak, hardly perceptible 
trace of the superior lamella, the others having the axial lamella 
only. A series of 1000 or more was taken. It occurs under stones, 
ete., in places where there is no shade. 
