22 PLEISTOCENE MAMMALIA. 



IV. CONCLUSIONS. 



The evidence for tlie view tliat the Ilyana from the caves is a species distinct from 

 the modern //. crociita may now be more fully considered. 



Olivier,^ writing in 1825, mentions the following features as characteristic of 

 H. spelaa : 



1. The upper surface of the skull is less arched than in //. crocuta, and the temporal 

 ridges do not unite so quickly to form a sagittal crest. 



2. Ail the bones of the metacarpals and metatarsals measured are without exception 

 shorter and thicker than in //. crocuta. 



Reference is also made to the relatively thick character of the bones in the cave hyaena 

 by Gaudry,^ who concludes that the animal was more thick-set than its living repre- 

 sentative, and suggests that it may have had a more crouching gait. 



Cuvier remarks, however, with regard to the teeth, that it is imjiossible to distinguish 

 those of H. spelaa from those of //. crocuta. 



De Blainville^ gives the following features as characteristic of iZ". spelaa : 



1. The form of the upper carnassial with the large size of the third lobe (talon).* 



2. The absence of the inner cusp on the tubercular portion of the lower carnassial. 



3. The size, which is \ larger than in //. crocuta. 



4. The greater extension and compression of the occipital crest. 



5. The increased thickness and shortness of the muzzle. 



6. The increased thickness and shortness of the limb bones. 



He remarks that of these characters the least important is the increased relative size, 

 and the most important the increased thickness of the limbs and elevation of the 

 occipital crest. Relative size depends on conditions of life, and comparisons as regards 

 size have too often been made between fossil individuals at the maximum of their 

 development, owing to savage life, and individuals raised in menageries. The character 

 of the occipital crest also differs much, according to the age of the animal. 



Owen ^ states that the upper true molar in H. spelaa is monoradicular, and quotes 

 this as a character distinguishing //. spelaa from //. crocuta. Dawkins," on the other 

 hand, shows that the tooth in question is sometimes mono-, sometimes bi-radicular, 

 and that the method of implantation cannot be quoted as a character of specific value. 



The modern view that there is no specific distinction between //. spelaa and 

 //. crocuta was first clearly stated by Boyd Dawkins in 1865," and is now almost 

 universally accepted. 



1 ' Oss. Foss.,' ed. 3, iv, p. 396. 



2 ' Mater. Hist. Temps Quat.' (4), 1892, p. 118. » ' Osteograpliie, Hyeues,' p. 39. 



* I cannot trace any difference as regards the form of the ui>per carnassial or the size of the 

 third lobe between H. speleea and H. crocuta. 



^ ' Brit. Foss. Maniiii.,' p. 150. ^ ' Nut. Hist. Eev.,' n. s., v. 



