192 On small Mammals from Salta and Jujuy. 



like the Bolivian A. fumeus that I at first supposed it to 

 he referable to that species, from which it is scarcely to be 

 distinguished externally except by its long fore-claws. 



Mr. Budin notes on one specimen, "caught at foot of 

 pine tree — among the roots." 



10. Dasyprocta variegata bolivia, Thos. 



? . 7 (young). Manuel Elordi. 

 llecently described from Yacuiba. 



11. Sylvilagus brasiliensis gibsoni, subsp. n. 



$ . 1. Manuel Elordi, Vermejo, Salta, 500 m. 25th July, 

 1917. B.M. no. 18.1.1.8. Type. 



Essentially similar to S. b. paraguensis, but the mottling 

 of the upper surface slightly less strong and the general 

 colour a little greyer. Crown with large greyish confluent 

 patches at the anterior bases of the ears, only a very small 

 greyish spot indicating their position in the allied form. 

 Under surface whiter, the white of the chest extending up 

 the chest above the level of the fore-limbs, and much 

 reducing the greyish-buff collar, which is little more than 

 an inch in antero-posterior diameter, as compared with 

 three or four inches in paraguensis. 



Skull about as in paraguensis. Postorbital processes not 

 touching terminally the bone of the frontal behind. Occi- 

 pital shelf with its posterior angles not developed, so that it 

 is nearly semicircular in shape, while it is practically square 

 in paraguensis ; but only one specimen of sallce is available 

 for comparison with three examples of paraguensis. 



Dimensions of the type (measured in the flesh) : — 



Head and body 310 mm. ; tail 10; hind foot 71 ; ear 55. 



Skull : greatest length 62*5 ; condylo-incisive length 56 ; 

 zygomatic breadth 31*5 ; upper tooth-series (alveoli) 12. 



Hab. and Type as above. 



The reduction of the dark collar and the presence of 

 the grey patches at the bases of the ears clearly indicate 

 a subspecific difference in this Sylvilagus of the Upper 

 Vermejo, as compared with the form found in Paraguay. 



This hare, the first and only known member of the 

 group occurring naturally in Argentina, I have named 

 after Mr. Ernest Gibson, to whom our Mammal Survey 

 of the Argentine has been so immensely indebted for the 

 help he has given in the collecting-trips* of Messrs. Grant, 

 Kemp, and Budin. 



