The Nautilus. 



Vol. VI. MAY, 1892. No. 1. 



PATULA STRIGOSA GOTJLD, IN ARIZONA. 



BY EGBERT E, C. STEARNS, WASHINGTON, D. C. 



The National Museum has recently received from Mr, Marcus 

 Baker, of the U. S. Geological Survey, numerous specimens (Mus. 

 no. 123,576) of the above snail shell collected by him at Coon 

 Mountain, in Arizona. From Mr. Baker I have learned the fol- 

 lowing : " Coon Mountain, from which these shells came, is a name 

 locally applied to a possible volcanic crater, situated some ten miles 

 south of Canyon Diablo, Arizona. It is near lat. 35° N., long. 111° 

 W. The crater is some 500 or 600 feet deep, ranging from 5200 

 feet above sea level at the bottom, to 5700 feet at the crest of the 

 rim. Within the crater is bedded sandstone, limestone (Aubrey) 

 and talus slope. The region is excessively arid. The dead shells 

 are found scatte^;ed along the interior slopes of the crater, more 

 especially on the south side. Almost all are dead. I think I found 

 a single living one, in the course of a week's working about, in this 

 vicinity. I do not remember finding any outside of the rim. Many 

 of the specimens were fresh, most of them dead and bleached." 



Compared with examples from more northerly regions where this 

 form abounds, and exhibits, as is well-known, extraordinary vari- 

 ability, these Coon Mountain specimens are rather under size or 

 dwarfed. They are also rather flat than elevated, and some of them 

 are more or less angulated at the periphery. The fresher examples 

 are slightly rufous, with two narrow revolving bands on the body 

 whorl. 



