42 



GASTROCOPTA, NORTH AMERICA, WEST INDIES. 



with a crest remote from the aperture and forming a project- 

 ing angle at the base; at last ascending; aperture strongly 

 lateral, rounded subtriangular, equaling one-third the alti- 

 tude of the shell, highest near its columellar side, with a 

 sinus above on the palatal side ; margin continuous, strongly 

 everted, broadest so below, without a lip thickening; parietal 

 lamella very large, strongly curved, nearer the periphery at 

 its inner end; angular lamella large, at its inner end united 

 with the side of the parietal, at the outer with the palatal 



FIG. 13. Gastrocopta ashmuni. a, 6, Florida Mts., N. M. ; c, Oak Creek, 

 Yavapai Co., Ariz. 



margin, thus closing the sinulus above; columellar lamella 

 large, spiral, ascending to the body whorl between the pari- 

 etal and columella; basal lamella and inferior palatal fold 

 deep in the throat, the former radial, the latter above it, 

 oblique ; superior palatal short, tooth-like, rather remote from 

 the margin; surface shining, with slight, irregular striae and 

 microscopically rugulose, as is also the nucleus; shell horn- 

 colored, transparent; lamellae and folds whitish. Alt. 2, diam. 

 1.1 mm. (Sterki). 



From Valencia Co., New Mexico, and the southern rim of 

 the Grand Canyon, Arizona, south to the Mexican boundary 

 from Nogales, Arizona, to the Big Hachet Mountains, New 



