MOLLUSCA OF THE SOUTHWESTERN STATES, XI—FROM THE TUCSON 
RANGE TO AJO, AND MOUNTAIN RANGES BETWEEN THE 
SAN PEDRO AND SANTA CRUZ RIVERS, ARIZONA. 
By Henry A. Pinspry anp JAMES H. Frrriss. 
We continue here the examination of mollusks of the desert 
mountains of the southwest carried on in former papers of this 
series. The accumulation of data on more or less similar faunas of 
the many mountain ranges of this region is, from the nature of 
the task, somewhat monotonous; yet such work is absolutely es- 
sential to an understanding of the problems of distribution and 
evolution. A study of the distribution and migrations of such 
desert genera as Sonorella, which we have under way, cannot be 
made until reasonably full local data are available. 
The records following relate almost wholly to the faunas of 
Pima County and the western border of Cochise County, Arizona. 
The explorations were made by one of us (J. H. F.) in 1917-18, 
continued in company with the late Mr. A. A. Hinkley, in 1919. 
Types of the new species and subspecies are in the museum of 
the Academy. Paratypes of all are in the Ferriss collection. 
gee List of stations and of mollusks collected from the Tucson Range west 
to Ajo. 
Il. List of stations and of mollusks collected in the Empire, Whetstone, 
Mustang, Huachuca, Santa Rita, Patagonia, San Cayento, Tumacacori and 
Pajaritos Ranges. 
III. Notes and descriptions of Sonorella, Oreohelix, Bulimulus and Holospira. 
IV. On Micrarionta rowelli (Newe.) and M. newcombi, new species. 
I. List oF STaTIONsS AND OF Mo.Luusks COLLECTED FROM THE 
Tucson RANGE To AJo. 
To the eastern man, Tucson seems to be upon the rim of the world, 
more so than San Diego. At Tucson it is Ajo, 150 miles westward, 
that is the land’s end and thus fascinating to explorers and miners. 
Contemplating the journey to Ajo, a little run was made out in 
that direction to the Tucson range about Christmas time, 1917, 
to try a new machine and to take a look at the road. Camp was 
made that afternoon at Pictured Rocks, a pass about the middle 
of the range, an hour from the city. The next day, Christmas, 
Frank Cole, our guide, hunter, cook and boss, brought in a wild 
pig, and Sonorella bones were found. The pig was baked with 
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