Ill] AND HISTORIC TIMES 143 



still survive ; again, it has been long known that Hipparion 

 had a deep fossa in front of the orbital bone, which is supposed 

 to have lodged a gland. Prof. Huxley in 1870 indicated the 

 existence of a rudimentary pre-orbital pit in the skull of Equus 

 sivalensis, an Indian fossil species, and Dr Forsyth Major in 1880 

 pointed out the existence of a similar feature in Equus stenonis, 

 the closely related species lf ound in the Pliocene beds of the 

 Val d'Arno and its somewhat later ally Equus quaggoides, 

 and he also showed its existence in the Quagga (cf. p. 76); 

 Mr Lydekker has recently directed attention to the occurrence 

 of what he considers "a vestige of the Hipparion's face-pit in 

 the skull of an Indian domesticated horse in the collection 

 of the British Museum," and to the occurrence of a similar 

 depression in the skull of the well-known racer Bend Or, in 

 which it is still shallower than in the Indian domesticated 

 horse. "From the occurrence of the feature in question in 

 these skulls, both of which probably belonged to horses of 

 Eastern origin, and its entire absence in all the skulls of the 

 prehistoric European horse," Mr Lydekker 1 has suggested 

 " that the blood-horse," unlike the " cold-blooded horse " of 

 Western Europe, may possibly have been the descendant of 

 Equus sivalensis. Mr Lydekker endeavours to meet the obvious 

 objection that a similar rudimentary pit existed in the European 

 E. stenonis by urging that "it had apparently disappeared in 

 the Pleistocene horse of Western Europe " (cf. p. 470). 



Mr Lydekker 2 has noted a like depression in the skull of 

 a young ass in the British Museum, whilst Mr Pocock has 

 pointed out a similar feature in the skull of a male Grant's 

 zebra in the same collection (p. 76) ; Mr Lydekker thus holds 

 that the thoroughbred horse as well as the ponies of Java and 

 Sulu are lineal descendants of E. sivalensis and Hipparion. 

 It may be pointed out that the large functional premolars, on 

 which he bases the relationship of the Javanese and Sulu 

 ponies to E. sivalensis, are likewise found in some zebras, and 

 that of the four species or sub-species of Equidae in which the 

 pre-orbital depression occurs three are undoubtedly of African 



1 Proc. Zool. Soc., 1904, pp. 426-7. 2 loc. cit., p. 431. 



