1918.] 



NATURAL SCIENCES OF PHILADELPHIA. 



323 



0. cooperi form apache, new form (pi. VII, figs. 7 to 8a). Rather 

 large size, dark or very dark coloring and subobsolete sculpture (the 

 spirals being especially weak) characterize the shells taken along the 

 Black River and Fish Creek, in Apache County, Arizona. The shell is 

 generally quite depressed and as openly umbilicate as the forms of 

 0. strigosa. The diameter is usually from 22 to 26 mm. Few have 

 the spire very high, and none are as high as many of the Blue River 

 shells. 



Fig. 15. Reproductive organs of OreohcUx strigosa meridionalis, the middle 

 figure drawn from the type specimen. 



