Merriam Descriptions of Ten New Kangaroo Rats. 79 



Cranial characters. Skull similar in general to that of agilis but 

 slightly smaller; frontoparietal shield more wedge-shaped (less squarish) ; 

 maxillary arch much broader and with angle strongly developed as in 

 streatori (in agilis the angle is weak and rounded) ; mastoids smaller and 

 flatter less deep vertically; occipital part of mastoid more ridged (less 

 swollen) ; incisors more slender. 



Measurements. Type specimen (9 ad. ) : total length, 300, tail verte 

 brae, 182; hind foot, 45. Average of 5 specimens from type locality: total 

 length, 292; tail vertebrae, 177; hind foot, 44. 



Perodipus perplexus sp. nov. 



Type from Walker Basin, Kern Co., Calif., No. ff-ffi c? ad., U. S. 

 National Museum, Biological Survey Collection. Collected July 15, 1891, 

 by Yernon Bailey. Orig. No. 3053. 



Range. Foothills and small interior valleys of the southern Sierra and 

 Tejon Mountains from Walker Basin to Tejon Pass. 



Characters. Ears large as in agilis, strikingly larger than in its neigh 

 bor streatori; color as in agilis, but sides of face from eye to whisker 

 patch broadly whitish, leaving a comparatively narrow median band of 

 body color reaching down from eyes to nose; dark tip of nose less marked. 



Cranial characters. Skull squarish and rather small, with broad front- 

 als and well developed post-lachrymal angle as in agilis. Differs from 

 agilis in slightly larger size; slightly larger incisors; maxillary arch 

 broader at base ( along f ronto-maxillary suture ) ; tympanic capsule rather 

 short and more inflated anteriorly. 



Measurements. Type specimen ( c? ad.): total length, 320; tail verte 

 bras, 195 ; hind foot, 46. Average of 5 specimens from type locality ( not fully 

 adult) : total length, 307; tail vertebrae, 183; hind foot, 44. Average of four 

 specimens from Tejon Pass (not fully adult) : total length, 307 ; tail verte 

 brae, 185; hind foot, 44.9. 



Perodipus simulans peninsularis subsp. nov. 



Type from Santo Domingo, Lower California, Mexico. No. 139,872, c? 

 yg. ad., U. S. National Museum, Biological Survey Collection. Col 

 lected Sept. 27, 1905, by Nelson and Goldman. Orig. No. 18,215. 



Characters. Similar in general to simulans but considerably larger, 

 tail crest more strongly developed, pelage more silky, ground color much 

 paler and of a different tint, and skull somewhat different. 



Color. Ground color pale buff only lightly lined with dark hairs ; nose 

 patch small and not connected with whisker-marks. 



Cranial characters. Skull like that of simulans but maxillary arch 

 slightly narrower, with angle less pronounced ; mastoids slightly larger 

 and deeper ; interparietal area narrower. 



Measurements. Type specimen ( c? yg. ad.): total length, 312; tail 

 vertebrae, 203; hind foot, 45. Average of 3 from type locality (all but the 

 type immature and slightly undersize): total length, 302; tail vertebrae, 

 191; hind foot, 43.5. 



