G8 MB. G. BUSK ON THE EXISTING SPECIES OP HTJiNA.. 



60x40, and in tlie other 75X50, equalling in fact the size of this 

 tooth in H. crocuta *. All the other teeth are also considerably- 

 larger in H. hrunnea ; but the greatest diiferences are observable in 

 the 2nd and 3rd premolars and in the molar. And with respect 

 to the proportionate size of these teeth a remarkable distinction 

 will be seen to exist. Whilst in H. striata the mean relative di- 

 mensions of the teeth stated in the above order, are 72 X 44, 

 78 X 43, and 81 x 40, the corresponding sizes in H. Irunnea are 

 84 X 55, 94 X 53, and 94 x 50. These figures show not only tliat 

 the three principal teeth in the molar series are a good deal 

 smaller in H. striata, but also that in that species the last 

 or molar tooth is larger than the penultimate, and that the other 

 two are not very greatly different in size ; whilst in H. Irunnea the 

 ultimate tooth is rather less than the penultimate, which, again, 

 is a good deal bigger than the antepenultimate — difierences in 

 which it will be seen in the Tables that H. Irunnea approaches H. 

 crocuta and H. spelcea. 



Having thus indicated the principal differences in dimensions 

 between H. striata and hrunnea, if we proceed to the differences in 

 form, &c., of certain parts of the cranium and of some of the teeth, 

 we shall find equally well-marked distinctions between the two 

 species. Commencing with the cranium, it may be remarked that 

 although in general form the brain-case does not differ very much, 

 yet that it is on the whole more compressed in H. Irunnea ; and 

 especially is this visible in the alisphenoid region, where, in both 

 H. crocuta and H. striata, the sides of the cranium project abruptly, 

 which is not the case in H. Irunnea. A difference in the form of 

 the occipital triangle will also be noticed. In S. striata as in H. 

 crocuta, the lateral ridges by which it is bounded, or the superior 

 occipital ridges, about an inch or an inch and a half below the 

 point of the sagittal spine bend outwards, whilst in S. hrunnea 

 they descend to the mastoid almost in a continuous even line 

 very slightly convex outwardly (figs. 4, 5) ; and they are also much 

 more prominent in H. striata. The upper border of the sagittal 

 crest is more arched in H. hrunnea. In H. striata the nasals reach 

 almost if not quite to the level of the highest point of the fronto- 

 maxillary suture, whilst in H. hrunnea they terminate nearly half 

 an inch below it. The infraorbital foramen is larger in H. hrun- 

 nea (0'55 to 0'45t). The width of the zygoma, as before remarked, 



* H. hrunnea is distinguished not only from H. striata, but also from H. 

 crocuta and S. spelcea, by its having the lower canine larger than the upper. 



t Probably commensurate with the greater size and abundance of the tactile 

 vibrissa! in that species. 



