108 Merrliim- — Xcn' Specific of TJionmyin/fi. 



Thomomys sinalo£e sp. iio\ . 



Tiipr from vMtata. Sinaloa. Mexico. No. SKi.i-J.'). $ ad.. U. S. Na- 

 tional Muscuni. Uiolo<j'ical Survey Collection. March 28. ]Si»<). K. A. 

 Goldman. < )ri^inal No. IH.IJO?. 



CJnirinii'rs. — Size rather large; color dull pale cliestnut brown. Ke- 

 lated 1(1 rirn'iiiis from Phoenix. Arizona, hvil darker and with distinctive 

 cranial characters. 



('iilor. — TTpperparts dull pale chest-nut brown, fading insensibly into 

 paler chestnut fulvous of underparts; region around moulh pale dusky, 

 not sharply contrasted with throat as in ccm'/n/.i. 



CrKiiiid !■//() fact ITS. — Skull ralher large and angular with strongly 

 xjirroiliiif/ (If'jjfcsscd Kitd sharpli/ atu/iilar zi/t/outato. Similar in general to 

 ceri'inus but shorter; zygomata more broadly spreading, more tlepressed, 

 and with more prominent anterior angle; bulhe smaller. 



MiiisiituniitHts. — Type specimen {$ ad.): tolal length 2:5:!; tail verte- 

 br;e 7:!; hind foot :!!. Average of (i adults from type locality: total 

 length 221; tail \ertebr;e 74; hind foot 31.5. 



Thomomys perditus sji. nov. 



Type fi'om Lampazos, Nuevo Leon, Mexico. No. HIjits' $ ''^^^■- ^- '^• 

 National Museum. Jiiological Survey Collection. .lanuary 22, 1891. G. 

 P. Streator. Original No. .")12. 



CharKrtcrs. — Size small; color drab gray; related \o tiiltcriixhni small- 

 er, grayer, and with distinctive .skvdl characters. 



(lohr. — Upperjiarls drab gray, strongly mixed with black-tipped hairs 

 and washed on sides with butfy (on sides of shoulders and rump becom- 

 ing butfy fulvous); region around mouth dusky; underparts and fore 

 legs and feet butfy salmon; hind feet .soiled whitish. 



Cranial char acterit. — Skull small; braincase broadly swollen; zygomata 

 moderately spreading, the outer sides parallel; interparietal subcpiad- 

 rate; nasals cuneate, notched behind, and ending about on plane of pre- 

 maxilla;; bull* medium or rather small. Differs from tolfmis in having 

 more cuneate nasals which are notched instead of truncate behind, and 

 which end about on plane of premaxiihe instead of falling far short of 

 premaxilhe; post zygomatic notch deeper and broader; upjier incisors 

 more prominent . 



Measurenwntx. — Type specimen ( $ ad.): total length 105; tail verte- 

 brae 59; hind foot 20.5. Average of 5 adults from type locality: total 

 length 185; tail vertebrie .55; hind fool 25. 



Thomomys ^oldmani sp. nov. 



Type ivom Mapimi, Durango, Mexico. No. 58,07.5, $ ad., T^ S. Na- 

 tional Museum, Biological Survey Collection. December 15, 189H. E. 

 A. Goldman. Original No. 240. 



