74 MB. G. BUSK ON THE EXISTING SPECIES OF HYJiNA. 



will show — 1. that in the form A the length of the cranium is 

 much less than in the other — that is to say, in the proportion of 

 993 to 1090; 2. that the zygomatic width is also less, in the 

 proportion of 703 to 715 ; and in fact that all the other cranial 

 measurements are less, except the interorbital width, which in 

 form A exceeds that of the other in the proportion of 240 to 225. 

 In the maxilla we find a very remarkable difference in the length 

 of the palate, which in the form A is represented by 470, whilst 

 in B it amounts to 550, and that the length of the palatals is in 

 the former case 199, and in the latter 240*. These figures show 

 that the length of the upper jaw is considerably greater in form 

 B ; but when we come to the width, the same difference does not 

 obtain, the transverse diameter of the maxilla, both at the 1st 

 premolar and at the 3rd premolar, being exactly the same in both 

 cases. And the same thing is apparent in the dimensions of the 

 incisor and of the molar series — the former being absolutely 

 wider in A, in the proportion of 165 to 150, whilst the latter se- 

 ries of teeth measures in it only 310, and in B 335. We perceive 

 therefore that the maxilla in form A is, as compared with the other, 

 disproportionately short and wide. On comparing the individual 

 teeth, even more important differences in dimensions are found 

 to exist. The 3rd incisor, notwithstanding the greater length of 

 the incisor series, is considerably smaller in form A than the 

 corresponding tooth in the other form, or in the proportion of 

 46 X 35 to 60 X 40. The same disproportion is found in the 

 canine, and in even a still greater ratio in the remaining teeth, 

 and especially in the 3rd and 4th premolars. In the 3rd pre- 

 molar the difference may be expressed by the figures 71 x 60 

 and 100 X 70, and in the 4th premolar by 130 x 44 and 150 x 85. 



Corresponding differences, as may be supposed, exist in the 

 mandible and its teeth. The only dimensions in which the lower 

 jaw in the form A exceeds the other are its height under the 

 molar, expressed by the figures 174 and 170, its width at the 2nd 

 premolar (302 and 300), and the length of the incisor series 

 (125 and 120) . We see therefore in this jaw as well as in the 

 maxilla a disproportionate width in comparison to its other di- 

 mensions, as will be more clearly seen on reference to the Table. 

 The much smaller dimensions of the teeth are even more strongly 

 marked in the mandibular than in the maxillary teeth; as an 

 instance, I would notice the comparative numbers standing oppo- 

 site the molar, viz, 106 x 46 and 120 x 52. 



* But there is reason to believe that the length in tliis case is exceptional. 



