1880.] DENTAL CHARACTERS OF THE CANIDjE. 253 



De Blainville long since figured and called attention to this feature 

 of the mandible in C cinereo-argentatus. 



These peculiarities are closely reproduced in the Thooid series, by 

 the skull of a South-American animal referred to Canis azara ', which 

 died in the Gardens of the Society, and to which I have alluded above 

 as C. asarce (a) (fig. 8 A, p. 251). The sagittal area is wide and 

 lyrate ; but the temporal ridges are not so strongly marked as in 

 C. littoralis. There are no strong depressions on the supraorbital 

 processes ; and the glabella is evenly arched, in correspondence with 

 the small but distinct frontal sinuses. The angular process of the 

 mandible is extremely strong, and its margin is thick and tumid. 

 Beneath it there is a well-developed subangular lobe (fig. 9 A, L). 



The following table of proportional measurements (basicranial axis 

 = 1 00) shows how closely C. asarce (a) and C. littoralis represent one 

 another. 



Table V. — Proportional Measurements of the Skull and Teeth of 

 C. azarae (a) and C. velox. 



C. asara (a). C. velox. 



Total length of bony palate 125 122 



„ breadth of „ 78-9 71 



„ length of £^^ 22-4 22-4 



— 17-7 18-1 



"^ IM 13-3 



» » ^1 27-7 27-2 



» » i;r2 14-4 15-7 



In both, a small accessory cusp is developed on the posterior part 

 of the outer face of the external anterior or principal cusp of the 

 lower sectorial tooth (fig. 9, A and B). 



Nevertheless the frontal sinuses and the form of the anterior part 

 of the cerebral cavity at once distinguish C. asarce (a), as a Thooid, 

 from C. littoralis. 



7. The transition between C. azaroi (a) and the macrodont Thooids 

 is furnished by the skull of an animal from Pernambuco, which died in 

 the Gardens, and came to me labelled "C.fulvipes" (fig. 10, p. 254). 

 The sagittal area is much narrower than in C. asarce (a) ; and the tem- 

 poral ridges unite into a short median crest behind. The glabella 

 is convex, and the postorbital constriction small, in correspondence 

 with the considerable development of the frontal sinuses. The an- 

 gular process of the mandible (fig. 9, C, A) is deep, strong, and thick, 

 but not tumid as in the foregoing species. The subangular lobe is 



^ Mr. Forbes informs me that this animal possessed a short straight creciim. 

 C. eancrivorus has a similar cajcum. In C. procyonoidcs, C.juhatus, and Icticyon 

 venaticus the C£ecum is longer and larger, but almost straight. In all the other 

 Canidse (certainly in C. lupus, C. laniger, C. domesticus. C. aureus, C. anthus, 

 C. antarcticus, C. azarcs, in Cyan, Lycaon, Vulpes, and Otocyon) it would appear 

 that the ctecum is large and coiled. (See Grarrod, P. Z. S. 1873 and 1878 ; 

 Murie, P. Z. S. 1873 ; Flower, P. Z. 8. 1880.) 



