1903.] Allen, New Rodents from Patagonia. 189 



Similar to C, sericeus but larger, much more strongly suffused 

 with fulvous, and less varied with black. 



Measurements. Type: Total length, 230; tail vertebrae, 65; hind 

 foot, 29. Fifteen males measure as follows: Total length, 224.5 (210- 

 240, with one 245 and one 250); tail vertebras, 69 (6075, with two 

 at 80); hind foot, 30 (28-32, and one 33). Seventeen females: Total 

 length, 213 (200-225); tail vertebrae, 62.2 (6065); hmd foot, 29.5 



(29-3 1 ). 



Skull. -Type, total length, 43; basal length, 39; zygomatic 

 breadth, 25; mastoid breadth, 25; interorbital breadth, 8.5; length of 

 nasals, 14.3; palatal length, 20; diastema, 6; upper molar teeth, 8; 

 lower jaw, inner base of incisors to posterior border of condyles, 28.5; 

 inner base of incisors to point of angular process, 33.5; height at con- 

 dyle, 8; width between condyles, 16; width between points of angular 

 processes, 27 ; lower molar teeth, 8.5. Seven old male skulls measure: 

 Total length, 43 (41-45); zygomatic breadth, 24.3 (23.5-25.3). Fif- 

 teen old female skulls: Total length, 38 (36-41); zygomatic breadth, 

 22.2 (21-24). 



Represented by 33 specimens 16 males and 17 females 

 all adult except 3, and all collected by Mr. Colburn, of which 

 1 6 were taken in the basalt canons south of Lake Buenos 

 Ayres, April 2 to May 15, and 17 near Swan Lake. Aside from 

 the young specimens, which are grayer and much less fulvous 

 than the adults, the variation in color consists in some speci- 

 mens being a little more strongly suffused with yellowish 

 than others, and in the distinctness of the tail stripe, which 

 is often wholly wanting, or present in varying degrees, from 

 a faint trace to a broad black stripe. 



This species is intermediate in size between C. sericeus 

 and C. mendocina, being larger than the former, and differing 

 from it in its more strongly fulvous and generally lighter 

 coloration, and from the latter in considerably smaller size 

 and entire absence of any reddish suffusion. 



Oxymycterus microtis, sp. nov. 



Type, No. 84234, U. S. Nat. Mus., $ ad., Pacific slope of the Cordil- 

 leras, near the head of the Rio Chico de Santa Cruz, March 7, 1897; 

 O. A. Peterson. 



Adult male (type) , March. Pelage thick, short, and fine, almost 

 mole-like in character. Pelage and general color almost exactly as 

 in Oxymycterus lanosus Thomas, but twice the size of that species, 



