MB. G. BUSK OK THE EXISTI^S'G SPECIES OF HTiENA. 75 



The above statement, together with the figures given in the 

 Table, is sufficient to show that there is every excuse to be made 

 for those who upon comparison of the two crania 1232 « and 

 12325 in the British Museum with those of the B form, numbered 

 822 a and 822 5, should have regarded them as specifically distinct. 

 But the two latter specimens might be exceptional, and it was neces- 

 sary to compare them with others bearing the same general type, 

 but of less dimensions and of younger age. Fortunately means 

 for doing this existed in the crania No. 4447 of the Soyal Col- 

 lege of Surgeons and No. 37783 in the British Museum. The 

 latter, as will be seen in Table IV., is of small dimensions ; but 

 the mean of these two crania, though generally less than in 822 a 

 and 822 I, is yet greatly in excess of No. 1232 a and 12325 &c. 

 The chief exceptions to this rule are, the zygomatic width, 

 which in the form A is 703, and in the others 660 ; the aural 

 width, 385 and 370 ; and the interorbital width, 240 and 225 ; the 

 transverse diameter of the maxilla at the 3rd premolar, 410 and 

 390, and at the 1st premolar, 260 and 242 ; and the length of the 

 incisor series, 165 and 151. In the mandible the long diameter 

 of the condyle is rather greater in form A, and the depth under 

 the molar considerably greater. The diasteme also is somewhat 

 longer. But in the size of the individual teeth the preponder- 

 ance is almost equally great against form A as we found it to 

 be in the case of form B. In a cast of the mandible of H. cro- 

 cuta in the possession of M. Lartet, taken from a specimen be- 

 longing to M. Yerreaux, of Paris, I took the measure of the lower 

 molar series, and found the numbers opposite each tooth to cor- 

 respond pretty nearly, though all are somewhat bigger, with those 

 of form B. 



Having thus gone over the principal numerical differences 

 between the various forms referred to S. crocuta, I would offer 

 a few remarks on the other diiferences observable between them. 



1. In both the crania of the form B, the infraorbitary fora- 

 mina are more compressed than in form A, in which these open- 

 ings are larger and rounder. 2. A very remarkable difference 

 exists in the much greater size of the tympanic bullae in form B, 

 in which they are rounded and inflated, and tolerably even on 

 the lower surface, which extends downwards rather below the 

 level of the point of the mastoid process. The same size and 

 form exists in the cranium No. 4447 of the Eoyal College of 

 Surgeons ; but in No. 37783 of the British Museum, a beautiful 

 specimen of a Wild Hyena from Natal, these bullae are very 



