ALLEN : MAMMALIA : MURID/E. 65 



deeply colored specimen in a series of 28 examples from the coast region, 

 near Santa Cruz, there is a striking contrast through the greater depth and 

 intensity of all the tints. Considering the climatic conditions of the two 

 regions — the moist, forested country of the Punta Arenas district and the 

 open, arid plains of the Santa Cruz district — the differences here shown 

 in the coloration of the two phases conform to what would be expected to 

 result from such diverse physical conditions. The differences are certainly 

 not to be accounted for by season or age. It finds an exact parallel in the 

 cases of Akodoii xa)if/ior/ii)ius as compared with A. canescens and ^. 

 niicJicclsoii as compared with A. macronyx. 



Reithrodon hatcheri Allen. 



(Plate XIV. Figs. %-%d. Skull.) 



Reithrodon hafchcn AWtn, Bull. Am. Mus. Nat. Hist, XIX, 191, May 9, 

 1903. Pacific slope of the Cordilleras, upper Rio Chico de Santa 

 Cruz, Patagonia. 



Similar in size and proportions to R. ctmiculoides, but much darker, 

 and with much less fulvous suffusion. 



Adult male (type), March. — Above dark grayish brown, varied with 

 black-tipped hairs, faintly suffused with grayish fulvous ; sides paler, pass- 

 ing gradually into the pale buff of the ventral surface; sides of nose, 

 lower border of cheeks, lower border of flanks, and whole ventral surface 

 cream-buff, except inside of thighs and adjoining portion of ventral sur- 

 face ; ears rather thinly haired, externally dull brown, internally yellowish 

 buff, the hairs at the anterior base of the ears whitish and the postauricular 

 patch pale buff; upper surface of the feet white ; soles of hind feet to base 

 of toes densely haired, dark brown, toes flesh-color; tail with a narrow 

 brown stripe above, sides and below dull whitish. 



Measurements. — Type: Total length, 230 mm.; tail vertebrae, 78 ; hind 

 foot, 34 ; Seven specimens (4 males and 3 females) measure ; Total 

 length, 215 {200-230); tail vertebrae, 77 (75-82); hind foot, 33.3 



(32-35)- 



Skull {\.y^t). — Total length, 35.7; basal length, 31 ; zygomatic breadth, 



20.5; interorbital breadth, 4; length of nasals, 16; palatal length, 17.5; 



palatal foramina, 9; diastema, 8.5; upper molar series, 6.4. 



Represented by ten specimens, all collected by Mr. Peterson in the 



Cordilleras at the head of the Rio Chico de Santa Cruz, and all but one 



