.small Mammals from North-western Rioja. 421 



Skull: median length 41 ; condylo-incisive length 405 ; 

 zygomatic breadth 24*5 ; nasals 14'3 ; interorbital breadth 8'5 ; 

 bimeatal breadth 26*7 ; palatilar length 17"3 ; upper tooth- 

 series, crowns 8'2 ; diameter of p 4 3*1. 



Flab, (of type). Portrerilloj at about 2G00 m. Other 

 specimens from L:i Invernada, 3800 m., both in the Famatina 

 chain. 



Type. Adult female. B.M. no. 20. 8. 4. 54. Original 

 number 229. Collected 8th April, 1920. 



As is natural, this Famatina tucu-tucu is nearly allied to 

 the C. coludo of Tinogasta, Catamarca, just to the north, 

 but its tail is uniformly shorter and its bullae smaller, so that 

 it would seem to need a special name. 



8. Lagidium famatince, sp. n. 



? . 961, 984, 987, and three separate skulls. La 

 Invernada. 



" Shot at an altitude of 3800 to 4000 m."—E. B. 



Near L. lockwoodi. Larger and less suffused with yellowish. 



Size rather larger than in lockwoodi, the skull about 95 to 

 98 mm. in greatest length, as compared with 85 to 90 in that 

 species. General colour above, of unbleached fur, bluish 

 grey, nearest to " neutral grey " of Ridgway, without the 

 brownish suffusion found in lockwoodi. Under surface 

 broadly washed with buffy or ochraceous ; white axillary 

 patches present in all three skins. 



Skull larger than that of lockwoodi, and differing from it in 

 various details, of which the following are the most tangible. 

 Muzzle distinctly longer, the diastema about 29 mm. in 

 all six skulls, as compared with 26 in five of lockwoodi. 

 Premaxillse not so broadened, the incisors not being so thick. 

 Lacrymal bones broadly developed, of irregular shape, their 

 antero-posterior approaching their transverse diameter ; in 

 lockwoodi they form hardly more than a narrow fringe to the 

 front edge of the orbit. Posterior part of skull higher owing 

 to the greater height of the bullae and meatus — in famatince 

 the height from the lowest point of the bulla to the highest on 

 the suprameatal island is about 30 mm., in lockwoodi 27 mm. ; 

 occipital shield differently shaped, its upright edges nearly 

 parallel, the nearest points at the upper corners of the mastoids 

 about 22 mm. from one another — in lockwoodi the shield is 

 narrow above, broadening below, the above measurement 

 about 17-18 mm. Bullae more swollen than in lockwoodi. 

 Incisors averaging lighter in colour, white in four of the 



