ARKIV FÖR ZOOLOGI. BAND 8. N:0 19. 



Guanacos 



Peru Patagonia Tierra del L. vicugna o 



ef 1 cT rather old cT Fuego ef ad. Peru 



Total length 261 316 307 309 234 236| 



Condylo-basal length 244 295 290 290 220 221 



Greatest width 128 152,5 146 144 117 122,, 



Least interorbital width ... 81 107 106,5 99 78 80, 



» postorbital » ... 56 64 64 69 59 58 

 Length of the three upper rao- 



lärs (crowns) 51 64,5 63 66,5 44 45 



Distance from front of c to back 



of m 3 115 132 131 145 96 100 



Width across middle of ra* 2 . . 64 75 75,5 74 55 59 

 Greatest transverse width of 



anterior lobe of ra 2 13 19 19 18 13 14 



Diastema between c and p 3 . . 40 — — 52 38 

 Least width of palate between 



premolars and c 8,6 13,3 14,7 14,6 11 10 



Width of palate between ante- 

 rior lobes of ra 3 39,6 45 45 48 34 34 



Greatest length of nasals late- 



rally 52,5 78 — 77,5 42 



Distance from lateral tip of 



nasal to tip of premaxillary 80 91 — 87 77 



this general difference in size there are also differences in pro- 

 portions between different parts of the skulls. In the Pata- 

 gonian Guanaco the distance from the back of the condyle 

 to the anterior brim of the orbit (149 mm. in an aclult male) 

 is smaller than the distance from the orbit to the tip of the 

 premaxillaries (172 mm.), but in the small Peruvian Guanaco 

 the former distance (131 in an adult male) is greater than the 

 latter (129 mm.). In the Patagonian Guanaco the distance 

 from the anterior brim of the orbit to the lateral tip of the 

 nasal (95 mm.) is contained only about 2 2 / 3 times in the dis- 

 tance from the tip of the nasal to the back of the occipital 

 crest (240 mm.), while in the small Peruvian Guanaco the 

 former distance (63 mm.) is contained more than 3 times in 

 the latter distance (193 mm.). This proves that the praeor- 

 bital region of the skull is, even comparatively, longer in the 

 Patagonian Guanaco. On the lower surface of the skull several 

 important differences are to be seen. In the small Peru- 

 vian Guanaco the palate is extremely narrowed in the region 

 between the premolars and the canines (conf. fig. 1). The in- 

 cisure in the posterior margin of the palate is broadhy rounded, 



