IIYy^'lNA CROCUTA. 11 



bliulc, (roiu which it is separated l)y ;> sniall cleft without any cusp; this is ihc most 

 common form. 



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

 of //. intermedia, de Serres, Dubrueil, and Jcanjean). 



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 

 I)rescnt (//. Perricri, Croizet and Jobert). 



Boyd 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 beiwcen the TeclJi of the Livin(j llyaciia crocuta and those of IIya?na 

 striiita and llyccna brunnca. — Tlie many and marked differences between the teeth of 

 //. crocuta and those of //. striata and //. hrunnea were long ago described by 

 de Blainvillc^ and by Busk,^ and may be summarised as follows : 



1. In //. striata and H. brunnea the upper molar is triradicular^ and tricuspid, and 

 rarely measures less than 0'5 by 0'2 iuch, being considerably larger than that of 

 //. crocuta. In 11. crocuta it is normally biradicular (occasionally monoradicular) and 

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



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

 arc subcqual antero-posteriorly, while in //. crocuta the last lobe is more than twice as 

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



3. In //. 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 11. crocuta. Cuvier noted the occurrence of this accessory j)oint, and 

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

 than in //. crocuta, whose low^er carnassial approaches somewhat closely to that of the 

 Eel id 03. 



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 

 //. crocuta than in II. striata, l^usk stated that the third upper premolar is also 

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

 behind. This, however, is not particularly apparent in the British ]\Iuseum skulls. 

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

 than in //. crocuta. 



5. The first, second, and third upper j)rcmolars in If. striata have the anterior cusp 

 better developed than in H. crocuta. 



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



3 According to dc Blainville, as noted \>j Da-\vkins (' Nat. Hist. Kev,,' u. s., v, p. 81), the molar 

 is monoradicular. 



* ' Oss. Foss.,' cd. 3, iii (1825), p. 399. 



