1909.] NATURAL SCIENCES OF PHILADELPHIA. 503 



of the Huachuca range. It differs from S. granulatissima chiefly 

 in the genitalia, the larger penis and the shape of the vagina being 

 constant features in the series of both species dissected. Specimens 

 have been dissected from five lots, from the head of Bear Canyon 

 (fig. 7), east fork of Cave, and from Miller Peak (fig. 5). One individ- 

 ual of several from the latter place seems to have the very minute 

 bud-like vestige of a nagellum. 



The shell will be recognized by its yellow, glossy surface and depressed 

 shape. The brownish forms from Ida and Ash Canyons, mentioned 

 above, require more study, with better fresh or alcoholic material than 

 we can command at this time. One from Ash Canyon is figured, fig. 18. 



Named in honor of Mr. L. E. Daniels, who accompanied Mr. Ferriss 

 in the expedition of 1907. 



Genus ASHMUNELLA Pils. and Ckll. 



The Ashmunellas of the Huachuca range, while very diverse in 

 appearance, belong to a single closely related group. Probably all 

 descended from an ancestral stock not unlike A. levettei angigyra, the 

 most widely distributed form, and the one showing most affinity to 

 species of the Chiricahua and other ranges. The common ancestry 

 of the whole series is demonstrated by the intermediate stages found 

 among the shells, and by the soft anatomy, which is so much alike in 

 all that it would probably be impossible to tell the species apart 

 without the shells, yet differing characteristically from the soft parts 

 of all Ashmunellas of the Chiricahuas or other ranges by the sacculated 

 or varicose spermatheca and the shape of the penis. 



The species and races form a beautiful chain of variations, pretty 

 completely connecting those having most complicated apertures with 

 those in which the aperture is toothless, thus: bifurca — levettei — 

 ursina — heterodonta — varicifera. 



Evolution has proceeded from fully toothed apertures towards 

 toothless apertures. In other words it has been retrogressive, marked 

 by degeneration of complex structures. 



Soft Anatomy of Ashmunella. — Time has not admitted a full exami- 

 nation of the anatomy, but the genitalia of many individuals have been 

 studied. These organs are so similar in all of the forms that one 

 description will suffice. The penis (P.) is rather large for an Ash- 

 munella. Inside it has six unequal fleshy longitudinal ridges, inter- 

 rupted in the middle (pi. XX, fig. 6). This point is marked exter- 

 nally by a slight constriction. The epi phallus (epi.) is very long, 

 terminating in a minute flagellum (/?.). The retractor muscle (rp.) 



