mainly of forms with a wide tolerance range for several environmental 

 factors, notably temperature and moisture. It is only in the more favorable 

 local areas, such as the higher elevations of desert mountain ranges, that 

 other forms with more exacting requirements come into the picture. 



FINDING SNAILS IN THE DESERT 



By Wendell O. Gregg 



My title may seem paradoxical since we think of snails as creatures 

 requiring considerable moisture; and land snails, with which this paper 

 deals principally, we associate with succulent gardens and humid forests. 

 But live land snails are to be found in the desert, and in some instances 

 without going to remote areas. 



An example of an easy-to-collect desert snail is Micrarionta hakerensis 

 Pilsbry and Lowe. It is to be found in fair abundance but a few yards 

 from Highway 91, the main route to Las Vegas. The exact spot is on the 

 east slope of a range of limestone hills about '^ "^ile west of Baker, in the 

 Mojave Desert. In dry weather it may be found by digging deep in the 

 rocks, but after a heavy rain the snails are near the surface, generally on 

 the under side of surface rocks. A similar locality is the east slope of a hill 

 south of Highway 66, just east of Newberry Springs where Micrarionta 

 unifasciata Willett is found. In the vicinity of Palm Springs on the Colo- 

 rado Desert there are 6 or 7 distinct forms, the type localities of which can 

 be reached in a single day's collecting trip. 



When traveling through the desert on a collecting trip, any rock slide 

 seen should be suspected of harboring snails. Micrarionta immaculata 

 Willett is found in such slides which are easily visible from the Vidal- 

 Blythe highway about 7 miles south of Vidal, in Riverside County. Twenty 

 recognized species and subspecies of Micrarionta live in our California 

 deserts and another 4 on the Arizona side of the Colorado River. They 

 are all to be found in rocky habitats. In our California deserts, 10 species 

 and subspecies of Sonorelix are always found in rocky habitats with the 

 one exception, S. bailey i (Bartsch) taken by Mr. Willett under dead agave 

 plants, in addition to the usual rocky habitat. Sonorelix (Herpeteros) 

 angelus Gregg was found by the writer under dead yuccas on the north 

 slopes of the west ends of Soledad and Mint canyons. 



Nine species of Helminthoglypta are true desert dwellers. H. mohave- 

 ana Berry is found near Victorville, on dry rocky hillsides, but is most 

 abundant in a less arid habitat along the Mojave River where it is crossed 

 by the Highway 91 bridge. On the hills almost directly across the river 

 from this point H. graniticola Berry is to be found beneath rock piles or 

 large flat rocks but in dry weather it burrows beneath the surface of the 

 soil under the rocks. I have also found it buried among the roots of desert 

 plants. H. crotalina Berry occurs in definite rock slides near the old Side- 

 winder Mine and H. jaegeri Berry on rocky hillsides in the Ord Mountains, 

 near Sweetwater Spring. As indicated by the name, the type lot of H. 



(75) 



