518 PROCEEDINGS OF THE ACADEMY OP [NOV. , 



muscle is inserted distally on the lung-floor, as usual. The vagina is 

 excessively long, longer than the penis, and of about equal diameter 

 throughout (slightly over 1 mm.). The spermatheca is globular, its 

 duct much shorter than the vagina. The organs of an individual 

 drowned and dissected fresh measure as follows: 



Length of penis, 55 mm. 



" " papilla, 31 



" " sheath, 7 



" epiphallus, 22 



" flagellum, 1.2 " 



" vagina, 70 " 



" spermatheca and duct, 31 " 



The liver is maroon colored when fresh. 



Types No. 94,313 A. N. S. P., from Rincon Peak, Rincon Mountains, 

 Cochise County, Arizona; cotypes in coll. Ferriss. Specimens were 

 also taken on Mt. Mica and Wrong Mountain, Rincon range. 



The jaw (pi. XXII, fig. 7) has six or seven strong ribs, projecting 

 on both margins. 



The radula has 26, 15, 1, 15, 26 teeth (pi. XXII, figs. 1, 2, 3). The 

 central and lateral teeth are unicuspid, the cusps stout and obtuse, 

 longer than the basal plates. At about the sixteenth tooth an ectocone 

 appears. Towards the outer edge of the radula the inner cusp becomes 

 bifid; and in many but not all of the outermost six or eight marginals 

 the ectocone is split into two or three denticles (fig. 3). 



Conchologically this form stands very close to S. ashmuni Bartsch, 

 from Richinbar, south of Prescott, Arizona; also found at Jerome, and 

 at Purtyman's ranch on Oak Creek, 40 miles from Jerome. It would 

 probably be scarcely possible to separate the two species by the shells 

 alone. The genitalia, however, are widely diverse. S. ashmuni 

 (Oak Creek) has genitalia of the type found in hachitcwia-like Sonorel- 

 las of the Peloncillo, Florida and Dos Cabezas ranges, while S. rinconen- 

 sis has the penis and vagina excessively lengthened While quite 

 unlike any known form, it seems nearer to S. virilis than to other species 

 which have been dissected, but differs from that by its far shorter 

 penis-papilla and by the vagina, which is much longer than the penis, 

 while in S. virilis the penis is longer. 



Plate XXII. — Figs. 1, 2, 3 — Sonorella rinconensis Pils. and Ferr. Central 

 lateral and marginal teeth. 

 Fig. 4 — Sonorella rinconensis. Type, genitalia. X 2. 

 Fig. 5— Sonorella dalli Bartsch. No. 94,384, genitalia. X 2 

 Fig. 6 — Sonorella dalli Bartsch. Jaw. 

 Fig. 7 — Sonorella rinconensis. Jaw. 

 Fig. 8 — Sonorella dalli. Teeth. 



