1912] Grinnell-Swarth: A Bat New to California 139 



The cranial peculiarities of orinomus are marked. The most 

 prominent general feature is the extraordinary flattening of the 

 skull, more extreme, even, than in .1/. occultus. In yumanensis, 

 californicus and pallidas the braincase is relatively inflated, 

 bulging dorsally, so that there is a comparatively deep "saddle" 

 or angle formed by the rostrum and forehead. The accompany- 

 ing drawing shows this peculiarity of orinomus, in comparison 



Fig. 1. Myotis californicus pallidas Stephens (1900, p. 153), topotype, 

 $; no. 7350; Valleeito, San Diego County, California; May 21, 1909; col- 

 lected by F. Stephens. X 3. 



Fig. 2. Myotis orinomus Elliot (1903, p. 228), <J; no. 2047; Garnet 

 Queen Mine, Santa Eosa Mountains, California; June 26, 1908; collected by 

 H. S. Swarth. X 3. 



with pallidus. In addition, as viewed from above, the rostral 

 region of the skull is very much broader than in either yumanen- 

 sis, californicus, or pallidus. Beneath, this breadth is occupied 

 to so large a degree by the molars, which are of greater trans- 

 verse diameter even than in yumanensis, that the palatal width 

 is but little greater than in californicus. The tooth row, how- 

 ever, is much longer in orinomus than in californicus. Although 

 in bulk of skull orinomus exceeds californicus and pallidus, the 

 interorbital constriction in the three species named is about the 

 same, that is, much less than in yumanensis. The width of brain- 

 case is nearly as great in orinomus as in yumanensis, but the 

 height is very much less. 



Our ten specimens of Myotis orinomus from California show 

 a moderate amount of individual variation in the characters 

 pointed out above. In flatness of braincase and broadness of 

 rostrum there is such uniformity as to preclude the possibility 

 of intergradation with any other species of Myotis known by us 

 to inhabit California. Its occurrence in the San Jacinto, San 

 Bernardino and Mount Whitney regions, in each of which areas 



