LÖNNBERG, ON SOME MAMMALS FROM THE ARGENTINE CHACO. .*> 



Zygomatic breadth 85,5 mm. 



Interorbital breadth 45,3 » 



Occipital breadth 65,5 » 



Least vertical distance between lower orbital l)rim and alvrolar 



margin of nr 26,6 » 



Breadth of braincase 60 » 



Breadth between outer sides of m- 57,5 » 



Maxillary tooth row 54,5 » 



Ratio of preorbital to condylobasal length 50,8 % 



Length (greatest) of nasals 57 mm 



Greatest breadth of nasals 23,5 » 



Breadth of skull across posterior end of premaxillaries 27.5 » 



Greatest breadth of m" 11,4 » 



Diastema of lower jaw 46,5 » 



Gnathion to front of anterior premolar 58,8 » 



Length of left (longest) antler from the burr 113,5 » 



Transverse diameter of pedicel just below burr 16,3 » 



Almost all these measurements are smaller tban those 

 which Allén has recorded for the males of 31. rufa rufa 

 and most of them are also smaller than the corresponding 

 ones for the females of the typical race. One of the most 

 important differences is perhaps the absolute and relative 

 shortness of the preorbital region, which is only 50,8 % of 

 the condylobasal length, although the animal certainly has 

 attained such an age that the preorbital region must have 

 reached its maximum. 



Another characteristic of some value is the shortness of 

 the maxillary tooth-row, which is considerably shorter not 

 only than in the normal adult females of the typical M. rufa, 

 but also than in such males which, according to Allén, 

 had their »teeth much worn» and thus in consequence of 

 this must have had their tooth-rows more or less reduced 

 in length below the normal condition. 



The premaxillse do not reach the nasals in this specimen. 



With regard to some of the oranial dimensions this 

 broeket resembles Mazama rufa jvcunda Thomas from Paranä. 

 The condylobasal length is, however, longer in the animal 

 from the Chaco Central, but the breadth between the outer 

 sides of m'^ much smaller, if adult male skulls are compared. 



