2 ARKIV FÖR ZOOLOGI. BAND 13. N:0 10. 



side of Rio Bermejo. The deer on the former side are smal- 

 ler than tbose of the latter, and this appears to be the case 

 not only with those of the Mazama nifa-gvouip, but with the 

 brown species as well. A specimen of M. simplicicornis from 

 Chaco Central bas thus most of the cranial measurements 

 smaller than those recorded by Allén from specimens re- 

 ferred to this species eollected in Paraguay (1. c., p. 547). 

 About this see below. 



The red group is represented by an adult male from 

 the Chaco Central, and a rather old male and a not quite 

 fully adult female from the Chaco Austral. These specimens 

 are not only considerable different inter se, but differ also 

 at the same time from the typical Mazama rufa Illiger 

 according to Allen's description. This discrepancy consists 

 chiefly in absolute and relative cranial dimensions, and the 

 more northern animal exhibits smaller dimensions than the 

 by Allén recorded minima, while the southern ones surpass 

 the maxima of the same author. To avoid future confusion 

 I think it therefore most suitable to describe them under 

 separate names, although it may be possible that a richer 

 material might prove, that the red broeket of the Chaco 

 Central falls within the limits of variation of the true Ma- 

 zama rufa. 



Mazama rufa toba^ n. subsp. 



A male signed : »Gama. Guazii uirä. Ind. Cabitå. 3. 

 Chaco Central. Rio de Oro. Rep. Arg. Mayo 1896. 



A. Ros.» 



The molars of especially the lower jaw of this animal 

 are somewhat worn, but it is still in its best age, and the 

 molar series of the upper jaw do not appear to have been 

 shortened by wearing. 



a" 

 Total length of skull 198 mm. 



Condylobasal length 187 > 



Occipitonasal length 170,5 » 



Preorbital length 95 » 



^ Named for the Toba indians which inhabit the Chaco. 



