1915.] NATURAL SCIENCES OF PHILADELPHIA. 377 
Station 15 (further east on the same branch, a little higher). 
Rather stout shells, with the mouth built out shortly (nearly 1 mm.) ; 
about 15 ribs; lamelle one or two. 12x4 mm. 
Station 13 (eastern peak of the rim of Tweed Canyon). Fine- 
ribbed, like Pl. XIV, figs. 5, 5a. 
Station 11 (steep, stony, arid, southern slope of ridge projecting 
into amphitheatre, vegetation xerophytic). The shells are greater 
in diameter than the types, very uniform in sculpture, having 16 or 
17 ribs on the penultimate whorl, the peristome built forward further 
than usual in the type lot. 10.5 x 3.7 mm. axial or axial and superior 
lamelle. 
Another lot, taken a couple of hundred feet higher, are similar 
in form, sculpture and lamelle; ribs 15 to 19. 
Station 12 (peak on eastern rim of amphitheatre). The shells 
are larger than at the preceding stations, with more ribs, 26 to 28 
on the penultimate whorl. Half of those opened have one, half 
two lamelle, the superior lamella not very strong. These shells 
are like those from Station 4 and 5. See Pl. XIV, figs. 4 to 40. 
Length 13.7, diam. 4.2 mm.; whorls 13. 
ce 12, (a9 4 “c ce 112. 
Station 40 (between crest and foothills, north end of the range). 
Stout, rather large shells, with a strongly developed columellar lamella 
only in several opened. 37 to 48 ribs, nearly or quite as wide as 
their intervals. (Pl. XIV, figs. 5, 5a). 
Length 12.3, diam. 4. mm. 
SY CO es a 
These shells have more ribs than any other colony of H. danielsi, 
and they may be referable to H. campestris cochiset. The shells are, 
however, larger than the latter, some of the ribs are broken down, 
as in danielsi, and the locality is distant from other known colonies 
of H. c. cochisei. Only a very small lot was taken, and, pending 
further collections, its identity may be left undecided. 
Station 39 (between crest and foothills at north end of the range). 
Much larger than the typical form, stouter, with few, strong and 
widely separated ribs. Only the axial lamella developed. (PI. 
XIV, figs. 2 to 2c). 
Length 13.3, diam. 4.8 mm.; whorls 13; ribs 15. 
13.5, 4.5 12>“ 45, 
ey ta a fa yg se AG 
Bae ee at el) gp Be 43, 
"Tate OS Aa 8 “49. © 492. 
