78 Merriam Descriptions of Ten New Kangaroo Rats. 



broadly and squarely spreading maxillary roots of zygomata, broad and 

 strongly angled ( almost hooked) maxillary arches, and long nasals. Com 

 pared with nevadensis and nitratoides (with which it agrees most closely) : 

 frontoparietal shield broader; skull broader across mastoids; maxillary 

 roots of zygomata more broadly and squarely spreading; mastoids some 

 what smaller (narrower) though posterior segment is fully inflated; nasals 

 long, as in nevadensis decidedly longer than in nitratoides. 



Measurements. Type specimen, ( cT ad.): total length, 240; tail verte 

 brae, 140; hind foot, 37. Skull: greatest length, 34.5; occipito-nasal length, 

 32.5; mastoid breadth, 22.5; maxillary breadth, 20. 



Perodipus stephensi sp. nov. 



Type from San Jacinto Valley, Kiverside County, Calif., No. |fff cT 

 ad., Merriam Collection. Collected Nov. 27, 1885, by Frank Stephens. 



Characters. Very distinct from all other species except streatori and 

 panamintinus both of which it resembles in the general squarish form of 

 the skull. Ears moderate, about as in panamintinus smaller than in 

 agilis. 



Color. Similar to panamintinus but darker. 



Cranial characters. General form of skull "squarish" as in streatori 

 and panamintinus; frontoparietal shield broadly " squarish " (contrasted 

 with wedge-shaped); maxillary root of zygomata broadly and squarely 

 spreading; maxillary arch broad and strongly angled. Compared with 

 panamintinus (probably its nearest relative) the skull is slightly smaller; 

 the interparietal area and basioccipital decidedly narrower ; rostrum and 

 nasals slightly smaller and more slender; mastoid bullse slightly fuller 

 and deeper ( best seen from behind ) . 



Compared with streatori (which it resembles surprisingly in general 

 form and size) the interparietal area averages narrower; outer angle of 

 parietal more produced, giving the cranial shield greater breadth poster 

 iorly ; mastoid bullge fuller and deeper vertically (best seen from behind) ; 

 incisors weaker. 



Perodipus morroensis sp. nov. 



Type from Morro, San Luis Obispo Co., Calif., No. ||||| ? ad., U. S. 

 National Museum, Biological Survey Collection. Collected Nov. 11, 1891, 

 by E. W. Nelson. Orig. No. 1464. 



Characters. A dark, highly colored form resembling simulans exter 

 nally except that the ear is smaller and nose bar blacker. Ears dark ; 

 nose spot jet black and continuous, with black whisker patches; back 

 darkest, with faint olivaceous tinge; front of face (eyes to nose) grizzled 

 buffy and dusky, much paler than top of head. and back; thigh patches 

 mixed with dusky and becoming black on ankles. Similar in general to 

 agilis but ears somewhat smaller; color slightly darker, particularly on 

 sides of head below ears and on end of nose ( which is black and connects 

 with whisker patches, thus forming a black bar across front of face ); 

 thigh patch darker and passing posteriorly into sooty black. 



