1922] Sch?nidt, Amphibians and Reptiles of Lower California 611 



GEOGRAPHIC ANALYSIS OF THE FAUNA 



The herpetological fauna of Lower California is relatively well 

 known and the number of species which further search may be expected 

 to add to the list, aside from insular forms, is probably small. Neverthe- 

 less, a serious gap in our knowledge of the distribution of the amphibians 

 and reptiles is the inadequacy of the collections from the middle of the 

 peninsula. Only one considerable collection comes from this area, that 

 made by Diguet and reported on by Mocquard (1899, p. 297, ff.), 

 although Van Denburgh records a few specimens from San Ignacio, 

 Comondu, and San Xavier. Unfortunately, the material available to 

 Mocquard was not critically examined and many of his identifications 

 are uncertain. I need only cite Chrysemys elegans, Uta stansburiana, and 

 Cnemidophorus grahamii listed by him, to indicate this uncertainty. 

 Holbrookia propinqua is recorded by him from Santa Rosalia; but the 

 genus is almost certainly absent from Lower California. The most im- 

 portant contributions to Lower Calif ornian herpetology which remain to 

 be made are a thorough exploration of this central part of the peninsula, 

 to determine the southern limit of the distribution of the northern forms 

 and the northern limits of the San Lucan fauna, and further studies of the 

 northeastern corner of the peninsula, where a number of additions to the 

 fauna may be expected from its close relations with the Colorado Desert. 

 It is possible to give a general review of the fauna, but the limits of the 

 ranges of the majority of the species are still undefined in one direction 

 or another. The chief defect of the present review is the absence of 

 complete and accurate data bearing on the habitat associations of the 

 species concerned. 



An investigation of the herpetology of the State of Sonora on the 

 east side of the Gulf of California could not fail to add greatly to our 

 understanding to the origin and relations of the Lower Californian 

 reptile fauna. 



The general conclusion of all who have dealt with the Sonoran rep- 

 tile fauna is that the Lower Californian fauna in its main features is 

 directly derived from the areas to the north. This conclusion I can fully 

 confirm. 



The Lower Californian herpetological fauna as listed below con- 

 tains 149 species and subspecies, 11 amphibians and 138 reptiles, the 

 latter composed of 90 lizards, 47 snakes and one turtle. Of this number, 

 39 lizards and 7 snakes are insular species, not found on the peninsula, 

 leaving a total of 92 species of reptiles at present known from the penin- 

 sula of Lower California. 



