2G 



THE GEOLOGIST. 



Eqtjus eossilis, V. Meyer, Palceologica, Svo, 1832, p. 79. Owen, 

 British Fossil Mamm. p. 383. 



The common British fossil horse, evidences of which are so com- 

 mon in our bone caves and pliocene deposits, Professor Owen states 

 to have been characterized by a larger head than the domesticated 

 races ; resembling, in this respect, the wild horses of Asia described 

 by Pallas, and in the same degree approximating the Tebrine and 

 Asinine groups. He also points out that the second and third molars 

 of both jaws are narrower transversely in comparison with their 

 anteroposterior diameter than in the existing horse ; a character 

 which, although present in the teeth derived from the Kirkdale Cave, 

 Oreston, and the newer pliocene blue clay at Cromer, was absent in 

 some of the Kent's Hole specimens. With respect to the more 

 important characters of the degree and mode of plication of the 

 enamel folds, no specific differences are demonstrated by Professor 

 Owen between the JE. fossilis and the E. caballus. The range of 

 variation, however, amongst the existing horses, is as yet undeter- 

 mined ; and I purpose, at a future time, to institute an accurate com- 

 parison, which would be, however, beyond the scope of the present 

 paper. In Norway, I am told, on the authority of Mr. A. D. 

 Bartlett, F.Z.S., that there still exists a breed of horses with traces of 

 the zebra-striping on the legs. It would be a most fruitful source of 

 information if the teeth of these horses were to be compared with 

 those of the fossil European species ; and I doubt not but that the 

 perseverance of the Superintendent of the Zoological Gardens will 

 be crowned with success, in obtaining living specimens of this breed. 



Colonel Hamilton Smith divides the species E. caballus, or true 

 horse, into four distinct origins : (a) the bay wild horse, or Tarpan ; 

 (b) the white villous wild horse ; (c) the black wild horse ; (d) the 

 Eelback, dun decussated. 



Characters. — Hitherto undetermined. 



Geog. Distrib. Northern Europe. — Geol. -Age. Pliocene. 



Equtjs plicidens, Owen, Brit. Foss. Mamm. 392 ; Report Brit 

 Ass. 231. (First upper molar, second upper molar, right lower canine 

 (juv.) astragalus, hoof phalanx.) 



Characters. — Enamel more complex than in E. cab at Jus ; crown of last upper molar 

 bilobed posteriorly, as in Ilippar'ion, from which it differs in the form of the tilth or in- 

 ternal prism of dentine in the upper molars, and in its continuation with the anterior 

 lobe of the tooth; differing, like E. fossilis, from E. caballtcs, in greater anteroposterior 

 diameter of crown of second upper molar, and less produced anterior angle of first molar. 

 (Owen.) 



Geog. Distrib. Oreston cave. — Geol. Age. Pliocene. 



Professor Owen says on this, " One cannot view the elegant fold- 

 ings of the enamel in the present fossil teeth, and in those of the 

 more ancient primigenial species (Hippotheria) of the Continental 

 Miocene deposits, without being reminded of the peculiar character 

 of the enamel of the molar teeth of the Elasmotherium, in which it is 

 folded in elegant festoons." It is indeed a singular fact, although 

 one accountable on a known biological law, that the more ancient 



