NATURAL SCIENCES OF PHILADELPHIA. 185 



discoveries made of the remains even of some of these, would indicate that 

 they still existed at a period so recent, that, in the language of Professor Leidy, 

 " it is probable the red man witnessed their declining existence." 



The peccary, or Mexican hog, an animal common in Mexico, is not indigenous 

 to the Atlantic United States; but his bones have been found associated with 

 human remains in caves used as cemeteries by the Aborigines.* " A tomb in 

 the city of Mexico," according to Clavigero, (?)f " was found to contain the 

 bones of an entire mammoth, the sepulchre appearing to have been formed ex- 

 pressly for their reception." And "Mr. Latrobe relates that during the prose- 

 cution of some excavations, near the city of Tezcuco, one of the ancient roads 

 or causeways was discovered, and on one side, only three feet below the sur- 

 face, in what may have been the ditch of the road, there lay the entire skeleton 

 of a mastodon. It bore every appearance of having been coeval with the period 

 when the road was used." 



Again I extract from Prof. Leidy's letter : J 



" The early existence of the genera to which our domestic animals belong, ha3 

 been adduced as presumptive evidence of the advent of man at a more remote 

 period than is usually assigned. It must be remembered, however, even at the 

 present time, that of some of these genera only a few species are domesticated : 

 thus of the existing six species of Equus (Horse) only two have ever been freely 

 brought under the dominion of man. 



" The horse did not exist in America at the time of its discovery by Europeans ; 

 but its remains, consisting chiefly of molar teeth, have now been so frequently 

 found in association with those of extinct animals, that it is generally admitted 

 once to have been an aboriginal inhabitant. When I first saw examples of 

 these remains I was not disposed to view them as relics of an extinct species ; 

 for although some presented characteristic differences from those of previously 

 known species, others were undistinguishable from the corresponding parts of the 

 domestic horse, and among them were intermediate varieties of form and size. 

 The subsequent discovery of the remains of two species of the closely allied 

 extinct genus Hipparion, in addition to the discovery of remains of two extinct 

 equine genera of an earlier geological period, leaves no room to doubt the 

 former existence of the horse on the American continent, contemporaneously 

 with the Mastodon and Megalonyx : and man probably was his companion." 



The iesult of the whole seems to be, that of the animals found fossil in the 

 post-pliocene beds, all the mollusca of the present day are undoubtedly a per- 

 petuation of the same species ; that of the higher order of vertebrata, the tapir, 

 peccary, raccoon, opossum, deer, elk, and musk-rat are equally entitled to be 

 considered the descendants of this ancient race. And if the claims of the 

 mollusca to this distinction rest upon a secure basis, because they are peculiar 

 to this country, and not obnoxious to suspicion of foreign immigration, it must 

 be recollected that this is equally true of the above named animals. 



Those which have hitherto been regarded as of recent and European origin, 

 are the horse, sheep, hog, and ox ; and it must be reserved perhaps for future 

 consideration to determine how far the negative proof of the non-existence of 

 these animals in the country at the time of its discovery may be regarded in each 

 individual case sufficiently strong to settle the question of his extinction and 

 reintroduction, when so many of his associates and contemporaries have suc- 

 ceeded in maintaining an unbroken line of descent down to the present day. 



Professor Agassiz's Letter. 



Key West, Feb. 25th, 1858. 

 Professor F. S. Holmes : 



^ Mv dear Sir : I have not forgotten my promise to write to you my impres- 

 sions respecting your important discoveries of fossil mammalia in the post- 



1859.] 



* Bradford's American Antiquities, p. 31. 



t Bradford's American Antiquities, p. 227. 



X Nott and Gliddon, Indigenous Races of the Earth, p. xviii. 



