1905.] NATURAL SCIENCES OF PHILADELPHIA. 285 



have well-developed cctocones. The marginal teeth are bicuspid, as 

 usual in Oreohelix, but the inner cusp is split. 



Oreohelix olappi Ferrlss. PI. XI, fig. 12 ; PI. XXV, figs. 51-56. 



Nautilus, XVIII, p. 53 (September, 1904). 



This is a remarkable snail, slightly resembling Pyramidula solitaria 

 on a small scale, but very different from any other Oreohelix by its 

 rapidly narrowing umbilicus and green or olivaceous cuticle. 



The smoothish integument is blackish on the head and tail, and 

 darker toward the foot margins, elsewhere tessellated with large poly- 

 gonal gray pigment spots. Sole cream colored. There are two irregu- 

 lar dorsal grooves. 



The kidney, 6.3 mm. long, is a thin-walled sack, its lumen large, 

 with strongly corrugated walls. The pericardium is fully 4 mm. long. 



The reproductive system (PI. XIX, fig. 8) resembles that of 0. chiri- 

 cahuana. The rather slender cylindric penis is enlarged at the summit, 

 the protuberance on the upper side (in the figure) hollow. The epi- 

 phallus enters through a very small acorn-shaped papilla. The walls 

 of the penis are thin, with a minute oblique corrugation meeting V-like 

 on one side. The penis measures 7, epiphallus 7, vagina 6, sperma- 

 theca and duct 13 mm. long. The penis retractor is inserted about 1.5 

 mm. from the base of the epiphallus. 



The jaw (PI. XXIII, fig. 26) is arcuate and striate vertically. 



The radula (PI. XXII, fig. 4) has about 29.1.29 teeth, of the general 

 form usual in Oreohelix. There are rudimentary ectocones on the 

 central teeth, at least where they are unworn. The laterals have simi- 

 lar outer cutting points. The marginal teeth are bicuspid. In general, 

 the teeth are between the unicuspid type and that with developed 

 ectocones. 



Explanation of Plates XI-XXVII. 



Plate XI. — Fig 11 was drawn by the author; the others are reproduced from 

 photographs. 



Figs. 1-3 — Oreohelix dnricahuana Pils. X 3§. Co-types. 



Figs. 4-6. — Oreohelix avalonensis Hemph. X cj. Santa Catalina Island, 

 California. 



Fig. 7. — O. avalonensis. Early whorls. X 6. 



Fig. 8. — Oreohelix yarapaineomexicana'Pils. Young specimen. X 3. Show- 

 ing embryonic whorls and two neanic whorls. 



Fig. 9. — O. y. neomexicana. Segment of base. Only the coarser spirals are 

 visible in the half-tone cut. 



Fig. 10. — Sonorella gramilatissima F'lh. No. 87,087. Miller Canyon. Por- 

 tion of last whorl above the periphery. X 7. 



Fig. 11. — Ashmunella angulata Fi\s. No. 87,113. Immature shell of 8 mm. 

 diameter showing temporary lip-rib. 



