1918.] NATURAL SCIENCES OF PHILADELPHIA. 325 



Oreohelix barbata Pils. 



The occurrence of this species in the Mogollons was a surprise, 

 as it was described from the Cave Creek region of the Chiricahuas, 

 far to the south. It does not inhabit the dryer northern half of the 

 Ghiricahua range, and its distribution is therefore conspicuously- 

 discontinuous. It evidently changes much more slowly than the 

 Ashmunellas, though some little differentiation may be seen as noted 

 below. 



In Dry Creek, it was taken in the slides with Ashmimella, at Stations 

 62, 64, 68, 70, 72, 75, 77, 78 and 79. In most of these colonies it 

 reaches large size, even larger than in the Chiricahuas. Tw^o examples 

 from Station 79 measure: height 8, diam. 16 mm., and height 9, 

 diam. 15.4 mm. Usually there are several circular fringes on the 

 last whorl above the periphery, and more on the base than in Chiri- 

 cahua examples. In the latter, fringes above are exceptional. Count- 

 ing that at the periphery, there are usually 8 to 11 spiral wreaths in 

 Dry Creek barbala, 6 to 10 in Chiricahuan specimens. In some lots 

 the cuticular appendages are mostly or quite lost in the adult stage. 

 Some consist partly of smaller individuals; and at Stations 64 and 75 

 all are small, 11-12 mm. in diameter. 



Cave Spring Canyon, Station 57. Very small, about 10 mm. 

 diameter, and agreeing well with 0. b. minima P. & F. (Proc. A. N. S. 

 Phila. 1910, p. 94, fig. 15) from Rucker Canyon, Chiricahuas. There 

 is probably no direct relationship, each being presumably a dimin- 

 utive race of the normal larger forms of their respective ranges. 

 These small forms show decadence by the deep descent of the last 

 whorl to the aperture. 



Willow Creek, Station 46. This is on the eastern slope of the Mo- 

 goUon watershed. The size is small, diameter about 11 mm. Cutic- 

 ular appendages usually deciduous. 



Thysanophora hornii (Gabb). 



Arizona: Station 45 (1913), John Lyon's Mountain, north of the 

 Little Dragoons. Blue River, Station 18 (1914), and Little Blue 

 River, Greenlee Co. 



New Mexico: Station 76, Dry Creek, west side of the ]\IogolIon 

 Mountains. 



Thysanophora ingersoUi (Bid.). 



Arizona: Reservation Creek, 9,500 ft.; Fish Creek; Horseshoe 

 bend of Black River, and 2 miles above, at 9-10,000 ft. Apache Co. 

 Cosper's pasture, Graham^Co. 



