452 



fitfLtE'TljT 56, UNITED STATES NATIONAL M0SEUM. 



scantily haired, not distinctly dusky above. Iris hazel. Length, 275 

 mm.; tail vertebrae, 130; ear from crown, 15; hind foot, 33. Skull, 

 20 by 35 mm. in greatest dimensions." Nasal bones sUghtly expanded 

 apically so as to produce a somewhat spatulate extremity. (Fig. 113.) 



a b c 



Fig. 113.— Sigmodon HiapiDua eeemicus. Skull of type, a, dobsal view; b, ventral view; 



V. LATERAL VIEW. 



Habits and local distribution. — -The Western Desert cotton-rat was 

 found in abundance on both sides of the Colorado River from Yuma 

 to the Gulf of California. It was most numerous about beds of wild 

 hemp which grow luxuriantly upon the broad savannas bordering the 

 Colorado about the mouth of the tributary called the Hardy River 

 or Hardys Colorado. On the Colorado Desert, where it lives in dense 

 growths of arrowwood, this species extends along the Salton River 

 as far as Seven Wells, in Lower California, becoming gradually scarce 

 as the stream recedes from the Colorado River. Four females, taken 

 March 24 and 25, 1894, would have given birth to four young each. 



Measurements of 48 specimens of the genus Sigmodon. 



Museum 

 number. 





Locality. 



Sex and 

 age. 





r 



28.0 

 27.0 

 31.5 



27.5 

 30.0 

 29.5 

 28.5 

 28.0 

 26.0 



31.5 

 32.0 

 31.5 



Sigmodon minimus. 



21187 

 21190 

 20612 



20613 

 20648 

 20644 

 20647 

 20724 

 20723 



21188 

 12701 c 



37291 

 37290 

 36772 



35773 

 35927 



35788 

 35869 

 35891 



37293 

 10995 

 83306 



1704 

 1760 

 765 



766 

 787 

 798 

 802 



2192 

 2231 

 2269 



Monument No. 40. 

 do 



La Noria, Santa Cruz Eiver, near 

 Monument No. 111. 



Apr. 26 

 May 13 

 Nov. 8 



.do. 

 .do. 

 -do. 

 -do. 

 .do. 

 .do. 



...do... 

 ...do... 

 Nov. 12 

 Nov. 13 

 Nov. 28 

 ...do... 



Sigmodon Mspidus texianus. 



Fort Clark, Kinney County, Texas. 



....do 



....do 



1893. 

 Jan. 12 

 Jan. 17 

 Feb. 5 



iirfad. 

 (fad. 

 ?ad. 



d' im. 



tf. 

 cf- 



rad. 

 cfad. 

 cT im. 



5 ad. 

 9 ad. 

 cfad. 



mm. 

 223 

 223 

 233 



212 

 119 



244 

 240 

 195 



264 

 246 



mm. 

 94 

 91 

 72 



96 

 91 

 110 

 100 

 98 



103 

 102 

 95 



mm. 

 14.0 

 12.0 

 15.5 



13.0 

 15.6 



15.0 

 14.0 

 13.0 



H.C 

 13.0 

 12.5 



" See also p. 



t-Type. 



American Museum ol Natural History. 



