﻿HYAENA CROCUTA. 11 



blade, from which it is. separated by a small cleft without any cusp; this is the most 

 common form. 



2. A small cusp intervenes between the aforesaid ridge and the blade (characteristic 

 of II. intermedia, cle Serres, Dubrueil, and Jeanjean). 



3. In place of the ridge occurring in 1 is a groove dividing the inner from the outer 

 part of the tubercle, which thus becomes bilobed. The cusp occurring in 2 is not 

 present (II. Perrieri, Croizet and Jobert). 



Eoyd Dawkins states that these are all to be regarded as mere variations of the 

 typical form, and by no means as characters of specific value. In this view he has been 

 followed by most subsequent writers. 



(4) Differences between the Teeth of the Living Hyaena crocuta and those of Hyaena 

 striata and Hyaena brunnea. — The many and marked differences between the teeth of 

 H. crocuta and those of H. striata and H. brunnea were long ago described by 

 de Blainville 1 and by Busk, 2 and may be summarised as follows: 



1. In II. striata and II. brunnea the upper molar is tri radicular s and tricuspid, and 

 rarely measures less than 0*5 by 0"2 inch, being considerably larger than that of 

 H. crocuta. In H. crocuta it is normally biraclicular (occasionally monoradicular) and 

 bicuspid, and is often absent (as in five skulls examined at the British Museum). 



2. In II. striata and H. brunnea the three lobes of the upper carnassial (pm. 4) 

 are subequal anteroposterior!}', while in H. crocuta the last lobe is more than twice as 

 long as the first. This fact was noted by Cuvier. 4 



3. In II. striata and H. brunnea there is a more or less distinct accessory point on 

 the inner side of the posterior cusp of the lower carnassial (m. 1), which is absent or 

 less developed in H. crocuta. Cuvier noted the occurrence of this accessory point, and 

 says it disappears with age. The lower carnassial is relatively much smaller in //. striata 

 than in II. crocuta, whose lower carnassial approaches somewhat closely to that of the 

 Midas. 



4. The second upper premolar is relatively smaller and. the third larger than in 

 //. striata, so that the contrast between the second and third is much greater in 

 II. crocuta than in II. striata. Busk stated that the third upper premolar is also 

 somewhat obliquely truncated behind in II. striata, while in II. crocuta it is square 

 behind. This, however, is not particularly apparent in the British Museum skulls. 

 In H. striata the second lower premolar has an anterior accessory cusp better developed 

 than in II. crocuta. 



5. The first, second, and third upper premolars in II. striata have the anterior cusp 

 better developed than in II. crocuta. 



1 ' Osteographie, Hyenes,' p. 21. 2 ' Trans. Zool. Soc.,' x (2), p. 77. 



3 According to de Blainville, as noted by Dawkins (' JSTat. Hist. Rev,,' n. s., v, p. 81), the molar 

 is monoradicular. 



4 ' Oss. Fobs.,' ed. 3, iii (1825), p. 399. 



