1910.] NATURAL SCIENCES OF PHILADELPHIA. $l 
Seven fully adult shells of the original lot measure: 
Am 10, -diam.15 mm. 
5 Aaa as 6 i ea 
ees 7,1 14.5. 
ce 9, ce 143 (73 
ese 148 
ras, “ ‘i449 * 
“cc 8.9 cc 14 “e 
~ 
This exact form has been found only at the type locality on the 
south side of Cave Creek below the place marked Camp on the map, 
p. 107, where it was taken in 1904, deeply imbedded in rotten shale near 
the water’s edge. About 30 specimens. 
’ In its native state O. clappi is covered with humus, perhaps attached 
by mucus. But few specimens were found except in the type Station. 
Its habit of burying deeply in the soil probably accounts for its rarity. 
Elsewhere in Cave Creek Canyon a slightly different form (see 
below) was found in 1906 at Stations 9, 11, 12, near 13, 14 and in the 
rayine west of Reed’s Mountain. These stations are all near the 
bottom of the canyon. It was not found higher up. Here it occurs 
with Sonorella, Ashmunella chiricahuana, A. ferrissi and A. angulata. 
2. Lower Cavé CREEK Form.—The shells taken in 1906 at Stations 
9, 11, 12 and near 13, 14, Cave Creek, are shghtly more angular at 
the periphery than the types, and the growth-wrinkles bear short 
cuticular lamellae where they pass over the peripheral angle in fresh 
and unrubbed individuals not fully mature. Often, but not always, 
there are three circular rows of inconspicuous granules at wide, equal 
intervals on the base, a weak or vanishing development of the basal 
sculpture of O. c. emigrans. The two brown bands (one at the outer 
third of the upper surface of the last whorl, the other below and near 
to the peripheral angle) are usually more distinct than in the type 
lot of clappi. A small series of fully adult shells from Station 12 
measure: 
Alt. 9, diam. 15.5 mm. 
Basiiiiee puma: 16 
smeeo ye (dana 
See S ahi Widest 
“ec 9, 6c 14.3 oe 
NS a ee 
seme) 6, 1h Bo 
~ 
