554 



MERRIAM 



without sharp line of demarcation; ears brown with a conspicuous 

 tuft of fulvous hairs at anterior base. 



Cranial characters. — Skull small, light and thin, of normal form; 

 zygomata standing out rather squarely anteriorly, the outer sides 

 nearly parallel or only slightly narrower anteriorly; nasals relatively 

 broad and bluntly pointed posteriorly falling short of premaxillae; in- 

 cisive foramina large and open for so small a skull ; audital bulla) 

 rather large; molai- series rather small, measuring 3.20 in length. 

 Compared with tenuis the skull is slightly larger, the braincase more 

 inflated and higher. 



Remarks. — This species is almost a miniature of R. Jiispidus of 

 the same region and adds another case to those already mentioned 

 in which two species, almost identical in external appearance, but one 

 very much larger than the other, inhabit the same locality. 



Measurements. — Type specimen {$ ad.): total length 169 mm.; 

 tail vertebrie 94; hind foot 22. Average of 3 from type locality : 

 total length 169; tail vertebrtc 97; hind foot 21.4. 



REITHRODONTOMYS GRISEOFLAVUS HELVOLUS 



subsp. nov. 



Type from Oaxaca City, Oaxaca, Mexico. No. 6S3S7. 9 ad. U. S. 



National Museum, Biological Survey Coll. Aug. 14, 1S94. E. 



W. Nelson and E. A. Goldman. Orig. no. 6576. 



Characters. — Similar to griseojlavus but upperparts everywhere 

 conspicuously redder, the back and sides intense ochraceous or orange 

 fulvous instead of buffy yellowish ; grizzling of black hairs less con- 

 spicuous. 



Remarks. — In color helvolus resembles levipes from San Sebas- 

 tian much more closely than it does griseojlavus., but its skull is 

 smaller and narrower than that of levipes^ with shorter tooth row, in 

 all of which respects it agrees with griseojlavus. 



Measure?nents.—Ty^e: specimen (9 ad.): total length 188 mm.; 

 tail vertebras iii; hind foot 20. Average of 6 from type locality: 

 total length 182; tail vertebrae 105.5; ^"''"'^^ ^^'^^ 20.1. 



REITHRODONTOMYS LEVIPES sp. nov. 



Type from San Sebastian, Jalisco, Mexico (altitude 3,000 ft.). No. 



8S057. $ ad. U. S. National Museum, Biological Survey Coll. 



March 30, 1897. E. W. Nelson and E. A. Goldman. Orig. no. 



10S39. 



Characters. — Size medium; ears rather small and thick; tail 

 rather short; pelage course; color fulvous. 



