94 THE NATURAL HISTORY REVIEW. 



ment of the cusp on the inner side, unites the characteristics of both 

 the second and third groups — in other words of H. intermedia and H. 

 Perrieri. It appears to me, therefore, conclusive, that these differ- 

 ences must be looked upon as variations merely from the typical 

 form of the lower molar of Hycena spelcea^ and by no means of spe- 

 cific value ; and this view is corroborated by the exact correspondence 

 in the form and proportions of the other teeth of the jaws in which 

 these abnormal differences occur, with those of the Spelaean Hyena. 

 Along with M. De Blainville,* therefore, though not on the same 

 grounds, I cannot admit the validity as species of either S. Perrieri 

 of Croizet and Jobert, or of H. intermedia of M. de Serres. 



§. ly. But on the other hand it may fairly be asked, " Is not the 

 presence of the small cusp at the inner base of the posterior blade of 

 the lower molar, evidence that the Hyena brunnea co-existed in the 

 caverns with the Spelaean Hyena ?" It is perfectly true that the above 

 characteristic is now confined to H. hrunnea alone of the existing 

 species : but the series of jaws mentioned above, proves that the fossil 

 Hyena was subject to a considerable number of variations — " un assez 

 bonnombre de variations qui etablissent des nuances intermediaires"t 

 — some of which point in the direction of the PL. hrunnea of Thunberg, 

 without, in my opinion, actually indicating that species. Just in pro- 

 portion as our knowledge increases of any group of animals so do the 

 lines of demarcation between the species become more and more 

 faint. Nature has every where worked ' catenatim hand seriatim,' 

 to the great confusion of systematists. If, for example, we turn to 

 the Carnivora, one of the best defined of natural groups, we find that 

 the various genera overlap, or if we take a particular genus — the 

 Bears — we find that in the recent as in the fossil state they present 

 variations almost infinite with reference to the dentition. The fossil 

 species {JJrsi arctos, arctoideuSy jpriscus and spelceus) shade off" into 

 one another, and present a series of lower jaws, in the Museums of 

 Taunton, Oxford, Leeds, and especially in the British Museum, 

 ofiering every variation in size, in the form of the teeth, in the shape of 

 the coronoid process, the angle and the condyle. Thus PL, spelcea 

 does not stand alone in its variations from the more usual form : 

 and as these have been traced step by step to the form confined now 

 to H. hrunnea, I cannot but conclude that this also is a variety only 



* Op. cit p. 45. and 48. 

 f De Blainville, Osteographie, Art. Hyena, p. 40. 



