Mcrriam New Kangaroo Rats. Ill 



breadth are essentially the same in the two species, but the naso-occipital 

 length in ornatus is much less and the zygornatic breadth very much greater- 

 While the zygomatic breadth is actually greater in ornatus, the breadth 

 across the top of the skull is decidedly less : hence when viewed from above, 

 the zygomatic arches stand out beyond the sides of the cranium, while in 

 phillipsi they are hidden beneath the edges of the frontals and parietals. 

 In ornatus the top of the cranium is much flatter than in phillipsi ; the 

 supraoccipital is narrower between the mastoid bullne ; the nasals are not 

 narrowed behind, and the ascending branches of the premax Okie are shorter 

 and more slender and have no trace of the posterior expansion commonly 

 present in phillipsi. The upper premolar is a single prism and its crown 

 has no trace of the antero-internal lobe of phil 



Dipodomys perotensis sp. nov. 



Type from PEROTE, VERA CRUZ, MEXICO. No. 54,285 9 ad. U. S. Nat. 

 Mus. Department of Agriculture Collection. Collected May 21, 1893 by 

 E. W. Nelson (Original number 4840). 



Measurements (taken in flesh). Type: Total length 265 ; tail vertebrae 162 ; 

 hind foot 40. Ear from anterior base 14 (in dry skin). 



Average measurements of 8 specimens from type locality : Total length 

 271 ; tail vertebra 168 ; hind foot 40.4. 



General characters. Similar in size and general appearance to 

 Dipodomys phillipsi and ornatus and intermediate between them 

 in coloration ; white terminal pencil short, and in one specimen 

 absent. Cranial characters substantial. 



Color. Upper parts brownish clay color, intimately mixed with and 

 darkened by blackish-tipped hairs on head and back ; strongly suffused with 

 ochraceous buff 011 sides and flanks; facial crescents large and black, meet 

 ing across the nose ; inner side of leg and sole blackish ; lateral white stripes 

 of tail disappearing near junction of distal and middle thirds ; white termi 

 nal pencil small and in one specimen absent (possibly the result of injury 

 in early life). 



Cranial characters. Skull similar to that of D. ornatus, but even narrower 

 on top [consequently very different from pliillipsi]; zygoma visible from 

 above ; top of skull more strongly arched anteropostenorly than any other 

 known species ; breadth of supraoccipital between inflated mastoids greater 

 than m phillipsi or ornatus. Angle of mandible larger than in phillipsi but 

 smaller than in ornatus. 



Dipodomys merriami nevadensis subsp. nov. 



lype from PYRAMID LAKE, NEVADA. No. 54,552 9 ad. U. S. Nat. Mus., 

 Department of Agriculture Collection. Collected June 26, 1893, by Vernon 

 Bailey (Original number 3,990). 



Measurements (taken in flesh). Type: Total length 240 ; tail vertebrte 140 ; 

 hind foot 39. Ear from anterior base 13 (in dry skin). 



