314 University of California Publications in Zoology [Vol. 12 



parietally. Diaboli is much like topotypes of T. me tea Merriam in 

 size and coloration, though not quite so reddish in corresponding 

 pelage, but differs in longer tail, and cranially in more bulging brain- 

 case, shorter nasals, and much more projecting incisors. 



Thomomys infrapallidus, new species 

 Carrizo Plain Gopher 



Type. — <$ old adult, no. 14181, Mus. Vert. Zool. ; seven miles south- 

 east of Simmler. Carrizo Plain, San Luis Obispo County, California; 

 May 25, 1911 ; collected by H. S. Swarth ; original no. 9138. 



Diagnosis. — A member of the bottae series of gophers; palest of 

 all the forms of this series so far as known from west-central Cali- 

 fornia; nearest in color to Thomomys angularis pascalis Merriam, but 

 decidedly paler beneath ; other characters : relatively large feet, long 

 fore claws, long tail, narrow and high braincase, moderately spreading 

 zygomatic arches, moderately projecting incisors, small molar teeth, 

 and very small auditory bullae. 



Material. — Nine specimens (nos. 14179-14187, Mus. Vert. Zool.). 

 all from Carrizo Plain, San Luis Obispo County, California: six from 

 seven miles southeast of Simmler, and three from five miles north of 

 Painted Rock; all collected in May, 1911, by H. S. Swarth. The 

 altitude of the Carrizo Plain varies from 1900 to 2500 feet. Faunally 

 and zonally it may be considered very arid, high Lower Sonoran. A 

 sparse prairie vegetation grows on ground that is more or less strongly 

 alkaline over most of the area. 



Measurements. — Of type (old adult male) : total length, 248 mm.; 

 tail, 76; hind foot 34; occipito-nasal length of cranium. 43.0; zygo- 

 matic width. 29.0; mastoid width, 22.8; height of braincase at bullae, 

 14.0. 



Comparisons. — From topotypes of Thomomys bottom pallescens 

 Rhoads, the new form differs at a glance in much smaller auditory 

 bullae, smaller and slenderer teeth, and more anteriorly projecting 

 incisors. From T. bottae bottae ( Kydoux and Gervais), infrapallidus 

 differs in very much paler, more clayey, coloration, smaller general 

 size, larger feet, longer tail, much smaller teeth, and smaller bullae. 

 From topotypes of T. angularis angularis Merriam, infrapallidus 

 differs in smaller size, paler coloration, especially below, narrower 



