CAXIS AZAE.E, 73 



and certainly the coloured plate of the external form given by Lund 

 looks very like a pale individual of C. azarce ; but the figure of the 

 skull and teeth seems to us to clinch the matter. His figures seem 

 carefully drawn and are probably accurate ; if so, the C. vetulus of 

 Lund must, we think, be the C. azane of AYied, for the proportion 

 borne by the fourth upper premolar to the upper molars is just that 

 which exists in the variety distinguished as C. fulmpes. 



Burmeister has also described two species under the terms C. vetulus 

 and C. fukicaudus, identifying them with the species so named by 

 Lund. In this identification he seems to us to be in error ; but we 

 reserve, till our consideration of the next species, any treatment of the 

 problem what these forms thus named by Burmeister may really be. 



The reader may think that we have united an excessive nimiber of 

 varieties under one specific name ; but we do not consider that many 

 of the characters upon which the authors of these reputed species have 

 dwelt merit any confidence as specifically distinctive marks. 



Thus Philippi even ventures to name a species without having seen 

 the skull of the form he thus names, and Burmeister dwells upon 

 such matters as the degree of development of the sagittal ridge and the 

 form of the postorbital processes. But these characters we have found 

 to vary greatly in ditterent specimens undoubtedly belonging to the 

 same species. 



The coloration presented in the adult condition, by what appears to 

 us to be a medium average variety of this species, is as follows : — 



Burmeister tells us * that the hair is much longer and more grey in 

 winter than in sunmier, also that the back becomes almost black 

 and the face greyish In-own instead of yellowish grey, and that the tint 

 of the limbs changes. At birth the young are entirely brown, except 

 that they are slightly greyish on the underparts. Sometimes individuals 

 are met with entirely white. 



The dorsal region of the body, which is covered with long hair, is 

 mottled with black and white, with black patches over the shoulders, 

 middle of the body, and rump. The sides of the body are grey. The 



* See ' Description physique de la Eepublique Argentine,' vol. iii. p. 148. 



L 



