1901.] Allen, New South American Muridce, etc. 4 1 * 



Measurements. Total length (type). 140.5 mm. ; head and body, 81 ; tail, 

 59.5; hind foot, 17.5; ear 15. Three adults (2 males and i female) give the fol- 

 lowing : Total length, 136.8(130-140.5); head and body, 77.8 (70-82.5); tail, 

 59(57.5-6o); hind foot, 17.8(17-19); ear, 12.6(12.5-15). 



The skull presents no differences except those of size from its near congeners. 

 Total length (type), 24 ; basilar length, 18 ; zygomatic breadth, 12 ; greatest 

 width of brain case, 11.2 ; interorbiial breadth, 5.2 ; nasals, 8 ; palate, 3 ; 

 palatal foramina, 5.5 ; upper toothrow, 4. 



Akodon tucumanensis belongs to the small-sized, soft-furred, 

 short-tailed, small-eared, short-nosed group of which A. olivaceus, 

 A. xanthorhinus, and A. canescens are typical representatives and 

 its nearest allies, from which, however, it is strongly distinct in 

 features of coloration. It is smaller than olivaceus, agreeing very 

 nearly in size with A. canescens and A. xanthorhinus. It is thus 

 far represented by only the three specimens above mentioned, all 

 taken at Tucuman, June 29, July i, and July 24, 1899, by Mr. L. 

 Dionelli. 



Metachirus nudicaudatus bolivianus, subsp. nov. 



Type, No. 1-6-7-73, British Museum, ? ad., Chulumani, Yungas, Bolivia, 

 alt. 2000 m., Feb. 14, 1901 ; P. O. Simons. 



Above pale yellowish gray, strongly varied with black, the black most de- 

 veloped along the median line, giving the effect of a blackish dorsal area, 

 which, in some specimens, takes the form of a quite distinct black median 

 line ; sides paler, more fulvous and less blackish ; below pale buff, this color 

 extending well up on the sides and on the outer edge of thigh and hind leg. 

 Head black, slightly varied with gray along the frontal region and top of the 

 nose ; a broad black stripe extends from the whiskers to the base of the ear, 

 enclosing the eye, and crossing over the head in front of the ears to join the 

 blackish median band on the head ; eye-spots ochraceous ; feet dull yellowish 

 gray brown, palms brownish flesh color, soles dusky ; ears pale brown ; tail 

 brown for about the basal two-thirds, the apical portion whitish. 



Measurements. Type : Total length, 498 mm. ; head and body, 225 ; tail, 



273 ; hind foot, 40 ; ear, 38. A series of 6 specimens, 3 males and 3 fe- 

 males, measure as follows : 



B. M. No. Sex. Head and body. Tail. Hind foot. Ear. 



1-6-7-71 $ 240 298 43 38 



1-6-7-69 $ 243 308 42 38.5 



1-6-7-70 $ juv. 195 253 39 36 



1-6-7-73 ? 225 273 40 38 



r-6-7-74 ? 240 290 41 39 



1-6-7-72 ? 238 300 42 38 



