282 MERRIAM 



Cranial chai-acters. — Skull large and broad ; anterior roots of 

 zygomata spreading, the outer sides as seen from above more nearly 

 parallel than usual (instead of strongly approximating anteriorly), 

 but dipping down below level of posterior root; nasals broad and 

 blunt posteriorly ; superciliary beads moderate ; incisive foramina 

 very large and broadly open; molars large (series 5 mm.). The 

 skull is very close to that of aztecus from Yautepec, Morelos, from 

 which it differs in slightly larger and higher braincase, heavier zygo- 

 mata, slightly larger bullae, palatal slits larger and more broadly 

 open (posteriorly) ; nasals broader posteriorly ; premaxillae slightly 

 shorter; molars broader anteriorly. 



Remarks. — This strongly marked species appears to be closely re- 

 lated to O. fulgens of Thomas, the type locality of which unfortu- 

 nately is unknown. Externally it differs ixox-a fulgens^ as described 

 by Thomas, in being much less bright fulvous. Thomas states that 

 fulgens is brighter than any of the species known to him, and in the 

 same paper describes O. melanotis^ which is very much moi^e highly 

 colored than crinitiis. The skull of crinitus ( $ ad.) is about 2 mm. 

 shorter than Thomas' measurements of the type of fulgetis; it is 

 also narrower across the zygomata and has shorter nasals. It is not 

 unlikely that crinitus will prove only a subspecies oi fulgens. Crani- 

 ally it is related to aztecus^ as shown above, but externally the resem- 

 blance is less close. It is larger than azteczcs, has smaller ears, larger 

 feet, longer tail, longer and softer pelage, and the belly is buffy-ful- 

 vous instead of white. 



Measurements. — Type specimen ( $ ad.) : total length 307 mm. ; 

 tail vertebrae 161 ; hind foot 37. 



ORYZOMYS CRINITUS AZTECUS subsp. nov. 



Type from Yautepec, Morelos, Mexico. No. 51 173 $ ad. U. S. 

 National Museum, Biological Survey Coll. Jan. 16, 1S93. E. W. 

 Nelson and E. A. Goldman. Original number 4290. 



Characters. — Closely related to crinitus^ from which it differs in 

 slightly smaller size and paler coloration; sides and rump pale buffy 

 fulvous; underparts 7f/^//e instead buffy fulvous. Old specimens in 

 worn pelage resemble albiventer. 



Color. — Upperparts buffy fulvous or ochraceous, redder in old 

 pelage, moderately lined with black hairs ; underparts white ; tail 

 brownish above, paler below. 



Cranial characters. — Skull similar to that of crinitus but nasals 

 and zygomata more slender; bullae smaller; incisive foramina not 

 quite so large. 



