1880.] 



DENTAL CHARACTERS OF THE CANID^. 



247 



rally the contour-hue is undulated, presenting one slight incurvation 

 in the region of the sylvian sulcus and another in that of the supra- 

 orbital sulcus (fig. 5, a), while a little angulation (fig. 5, b, b,) marks 

 the junction of the olfactory lobes with the cerebral hemispheres 

 In Vams azarcB the cerebral hemispheres immediately behind the 

 supraorbital fissure widen out abruptly (fig. 5, a), and the lateral 

 contour, instead of being slightly incurved at this point, presents a 

 sharp rectangular inflection. The frontal lobe anterior to the supra- 

 orbital sulcus is_ much longer in C. azarcB (a-b') than in C. vidpes 

 {a-b); and the Drain is considerably wider behind in the latter. 



Fig. 0. 



Superimposed outlines of the casts of the ci-uuial cavities of C. azara and 

 C. vuJpes, viewed from above. The thin line belongs to "the former 

 the tliick line to the latter. ' 



a, the supraorbital sulcus ; b, the junction of the olfactory lobe with the 

 cerebral hemisphere in C. viilpcs ; b', in C. asarm. 



Thus, notwithstanding the extremely close resemblance of these 

 two skulls, there is a very readily discernible difference between 

 theni in the presence of frontal sinuses and the peculiar character 

 of the anterior part of the cranial cavity in C. azarcB, while both 

 these features are absent in C. vulpes. These differences have 

 nothing to do with size or age, inasmuch as the two skulls are 

 almost identical in size and are both fully adult. Nevertheless I 

 do not know that I should have been disposed to attach any great 

 importance to such characters, if I had not found, on examining a 

 large number of canine animals, that they may be disposed in two 



