Sept. 1847.] 263 



the horses of the Spaniards to the aboriginal inhabitants of the country, for it 

 is very remarkable that the genus Equus should have so entirely passed away 

 from the vast pastures of the western world, in after ages to be replaced by 

 a foreign species to which the country has proved so well adapted ; and it is 

 impossible, in the present state of our knowledge, to conceive what could 

 have been the circumstances which have been so universally destructive to the 

 genus upon one continent, and so partial in its influence upon the other. 



The remains are by no means unfrequent, and according to William Cooper, 

 the author of a paper entitled " Notices of Big-Bone Lick," in Featherstonhaugh's 

 "Journal of Geology,"* the first printed notice of them occurs in Mitchell's 

 "Catalogue of Organic Remains, "f upon referring to which, I find mentioned 

 pp. 7, 8, that a cervical vertebra and teeth of the horse were found associated 

 with the Mastodon, &c, in a tract extending from the base of the Neversink 

 Hills to Bordentown, New Jersey. The author of " Notices, &c." also men- 

 tions the remains of the horse being found at Big-Bone Lick, but speaks doubt- 

 fully as to the authenticity of such remains having been found in a fossil state 

 in this country, and says, p. 208, " I saw nothing in support of it myself, nor 

 have I met wilh any person who could answer for such a fact from his own 

 careful observation." 



Dr. HarlanJ mentions the sparing existence of fossil remains of the horse, 

 which, from the heading of his chapter, he has referred to the same species as 

 the existing Equus caballus. 



The most satifactory account, however, with which I am acquainted, is given 

 by Mr. Owen in the Zoology of the Voyage of the Beagle, Part 1, Fossil Mam- 

 malia, p. 109, and is derived from two teeth obtained by Mr. Darwin in South 

 America. One of them, a superior molar, was far decomposed, and Mr. Owen 

 observes, " every point of comparison that could be established, proved it to 

 differ from the tooth of the common Equus caballus only in a slight inferiority 

 of size." The other a superior left molar, was found with the Mastodon, &c, 

 in the province of Entre Rios, and is figured (PI. xxxii. figs. 13 and 14,) in the 

 work. One of the figures represents an antero-lateral view of the tooth, and is 

 rather smaller in size, and is much more curved than in the corresponding 

 tooth of the recent E. caballus. The other figure represents the crown of the 

 tooth and indicates the diameters to be somewhat less. From what Mr. Owen 

 remarks in the " British Fossil Mammalia, 5 '^ this is a species which he proved 

 to be distinct from all European fossil and existing species, and from the 

 greater degree of curvature of the upper molars|| he has designated it under 

 the name of Equus curvidens. In the cabinet of the Academy there are a num- 

 ber of specimens of American fossil horse teeth, which I refer to two distinct 

 and well marked species. 



The first of these I consider as identical with the Equus curvidens, of which 



*Philada., 1831, vol. 1, p. 208. fNew York, 1826. 



jMed. and Phys. Researches, Philada., 1835, p. 267. 



^London, 1846, p. 398. 



HOdontography. By R. Owen, Esq., London, 1S40-45, vol. 1, p,. 575. 



36 



