258 PROCEEDINGS OF THE ACADEMY OF [Mch., 



mm., width of umbilicus 4.7 mm., or even larger 29.5 x 15.5 mm. 

 They exceed S. ashmuni Bartsch in size, and are larger than any Sono- 

 rella on record (PL XVII, figs. 1,2). The aperture is ample, 12.9 x 14.5 

 mm. 



Another lot (86,496, A. N. 8. P.), figured on PI. XVII, figs. 3-6, from 

 the same locality, consists of smaller specimens. Some are typical 

 hachitana in form and size except that the last whoj-l descends more 

 deeply in front, making the aperture subhorizontal in some specimens 

 (figs. 5, 6). In a few specimens the suprapcripheral band is almost 

 obsolete, very narrow and interrupted (figs. 3, 4), but most of them are 

 pale reddish-brown, fading to white in the middle region of the base, 

 and with a white or whitish band on each side of the dark supra- 

 peripheral l^elt. 



Alt. 14.5, diam. 25.4, width of umbihcus 4 mm. 



3.9 '' 



u ^ u 



3.9 " 



" 2.9 " 

 3.9 '' 

 3.8 " 



Specimens of this lot were sent alive. 



The pale sole is indistinctly tripartite, extremely weak impressed 

 lines dividing it in some specimens, not traceable in others. The back 

 is slate or blue-blackish, the tail brown above, paler toward the foot- 

 edges. The surface is finely pebble-granulate. There is a pair of 

 indistinct dorsal grooves, and the genital furrow is traceable only near 

 the mantle. The tail is depressed, with a very faint median groove. 



The genitalia (PI. XX, fig. 12) show no differences of any moment 

 from the form of hachitana from Purtyman's ranch, Arizona, figm-ed 

 by me in 1900, except in the shape of the spermatheca, which, however, 

 is not constant in the Purtyman's lot. The individuals examined were 

 partly not fully developed, and possibly older specimens will show a 

 somewhat stouter vagina and penis than that figured. The penis 

 papilla is long and slender, not convoluted in tlie specimen opened. 



The jaw (PI. XXIII, fig. 20) lias eight ribs. 



The radula is somewhat unlike other Sonorellas examined in the 

 central tooth, which is narrower than the adjacent laterals. There 

 are 55.1.55 teeth, an ectocone appearing on the fifteenth. Both cusps 

 are bifid on most of the marginal teeth, the mesocone + entocone being 



