OCR Text |
Show 110 DR. ST. G. MIVART ON [Mar. 18, premolar is very small, and the two upper molars compared with the fourth upper premolar are only as 122 to 100. But in the specimen at the British Museum now referred to, the upper molars are very large, bearing to the fourth upper premolar a proportion of 160 to 100, or just about the proportions exhibited by skulls of C. vetulus and Burmeister's figure of tbe dentition of that species. It cannot therefore be C. brasiliensis. Lund's C. brasiliensis much more resembles C. cancrivorus, as Burmeister (in his « Fauna ') took it to be, though later (Archiv f. Fig. 6. Surfaces of upper molars of Surfaces of molar teeth of lower Canis urostictus. jaw of Canis urostictus. Natur. ii. vol. i. p. 120) he was more inclined to regard it as distinct from that species. Certainly the aspect of the figure given by Lund differs considerably from any skull of C. cancrivorus I have noticed, and its outline reminds one a good deal of that seen in the genus Cyon. In the proportions of the teeth, however, it is like C. cancrivorus. In four skulls of the last-named species I find the average length of P. 4 is 1 -27 and that of M. l + M . 2 is 1-57, or as \QQ to 123, with which Lund's C. brasiliensis almost perfectly agrees. It is interesting to note that the C. microtis of Sclater (fig. 7, p. Ill)1 shows its affinity in this respect to C. cancrivorus, although I believe it to be a distinct species, P-jl being 1-30 and M. 1-f-M. 2 beino- 1-65, or as 100 to 126. As for the skin and skull (1033 E ) in the British Museum, which cannot be C. brasiliensis, it is also destitute of the characters ascribed to either C. vetulus or C.fulvicaudus of Burmeister, while its skull and dentition are so peculiar that it demands to be marked off as at least a distinct variety, possibly a species. The most distinct external mark about it is a longitudinal black stripe along the 1 P.Z. s. 1882, p. 631, pi. xlvii. |