1910.] NATURAL SCIENCES OF PHILADELPHIA. 93 



aperture. They were found in a talus upon an eastern slope of a 

 steep mountain side, and possessed the best developed, longest and 

 most persistent cuticular wreaths. 



A second colony in the head of one of the eastern forks of Turkey 

 Creek, found in 1908, approaches more closely the Barfoot Park series. 

 The shell is greenish under a pale brownish cuticle with a red band; 

 five short cuticular wreaths ; last whorl drops 1 mm. ; margins of aper- 

 ture connected by thick callus. Diam. 12, alt. 7 mm. 



These snails live in numerous colonies around the region of the 

 Falls of Cave Creek and the heads of the branches northward as far as 

 Turkey Creek. As the original photographic figures do not show the 

 shape clearly, a new figure has been drawn (fig. 14) of a shell denuded 

 of cuticular fringes, from Cave Creek, Station 4. 



Blunt-edged Variety. — In Barfoot Park, Rustler's Park, at about 

 9,000 feet, a slide at the head of Turkey Creek, Ash fork of Cave Creek, 

 Snow-shed Mountain at the head of Cave Creek, and the head of 

 Rock Creek, a form occurs in which the shell is smaller than typical 

 O. barbata and in fully adult shells the last whorl often descends the 

 full width of the former whorl: the periphery also is somewhat less 

 sharply angular, and becomes almost rounded near the aperture. 



Alt. 5.5, diam. 11.3 mm., Station, Barfoot Park. 



iC ft "11 " " " " 



This is distinctly a decadent form, as denoted by the tendency of 

 adult shells to assume the old-age feature of a very deeply descending- 

 last whorl. In Barfoot Park it lives in a deep slide of igneous rock 

 having a southern exposure. In Rustler's Park in a few stones on 

 the hillside. 



On the Ash fork of Cave Creek a colony has 44, whorls, the shell is 

 white under the cuticle, which is dark reddish brown above, lighter 

 brown below; occasionally with five cuticular fringes; last whorl drops 

 1 mm. Diam. 12, alt. 6£ mm., aperture 44; mm. 



A colony at the spring branch of Rucker Canyon, north side and near 

 the head, Station 10a, resembles the above closely (pi. VI, figs. 4, 5). 

 The umbilicus is a little more open, cuticle dark reddish brown, banded 

 with red above; six cuticular fringes. Diam. 124, alt. 6 mm. It is 

 strongly angular to the^aperture, and the last whorl falls much more 

 in front than is usual in Cave Creek shells. 



In a slide of rock on the north side at the head of Raspberry Gulch 

 (a tributary of Rucker Creek, which it enters at the Box Canyon) a 

 colony had only 4 whorls. The umbilicus measured 34, mm. wide. 

 Cuticle dark reddish brown, with a short fringe on the periphery; last 

 whorl drops 14, mm. Diam. 12, alt. 64. 



