344 



PROCEEDINGS OF THE ACADEMY OF 



[May, 



0. strigosa depressa (Ckll.). Pilsbry, Proc. A. N. S. Phila. 1905 

 PL XXII, figs. 1-3 (Pecos, N. M.); also from Colorado Springs, 

 near McCammon, Idaho, and Ogden Canyon, Utah. 



0. rugosa (Hemph.). See fig. la. Formula 19, 13, 1, 13, 19. 



0. metcalfei (Ckll.). Formula 17, 11, 1, 11, 17. 



0. concentrata (Dall). Pilsbry, Proc. A. N. S. Phila., 1905, p. 276 

 (Form huachucana). 



0. yavapai (Pils.). Pilsbry, Proc. A. N. S. Phila., 1905, PI. XXII, 

 fig. 7. 



Fig. 1. — Central and two inner lateral teeth of (a) Oreohelix rugosa, and (b) 0. 



hendersoni. 



In the second group the central and all lateral and marginal teeth 

 have sicle-cusps. Of this kind are : 



O. idahoensis (Newc). Binney, T. M. vol. V, PI. IV, fig. i. 



0. hemphilli (Newc.). 4 Binney, T. M. vol. V, PL IV, fig. j. 



0. barbata Pils., Pilsbry, Proc. A. N. S. Phila., 1905, PL XXII, fig. 6. 



O. chiricahuana Pils., Pilsbrv, Proc. A. N. S. Phila., 1905, PL XXII, 



figs. 10, 11. 

 0. clappi Ferriss, Pilsbry, Proc. A. N. S. Phila., 1905, PL XXII, fig. 4. 



In O. clappi the cusps and cutting points on the central teeth are 

 very small. In O. hendersoni (fig. 16) they are small and partly united 

 with the lateral cutting edges of the middle cusp. This species is transi- 

 tional to the form of teeth found in O. cooperi, O. haydeni and others. 

 There is therefore no hard and fast line of demarcation between the 

 two groups, although nearly all of the species examined are seen at 

 once to belong to one or the other, and the form of the teeth is there- 

 fore a useful specific character. 



Nearly all of the radulse examined have 29 to 33 teeth on each 

 side of the central tooth. A few have not so many, 0. yavapai 

 having 26, O. barbata 23, and 0. hemphilli, according to Binney, 20. 



4 Binney reported O. hemphilli from "Manitou, Williams Canyon, Colorado." 

 The shell from this place needs comparison with the type of hemphilli. Whether 

 his figure of the teeth was from the Nevada or the Colorado form is not known. 

 Fig. 157, Man. Amer. Land Shells, p. 168, is not very characteristic, and if hemp- 

 hilli, it is an immature individual. The tvpe of O. hemphilli is No. 23,060 

 A. N. S. P. 



