BLAKE — DISTRIBUTION OF MASTODON. 



471 



polar limit of the Proboscidea is 32 degrees South ; and we have evi- 

 dence of an American Mastodon in nearly the same latitude. But, 

 upon the supposition that the state of the South American continent 

 was analogous to the existing one, ordinary readers can hardly realize 

 the fact that a species of elephant should have existed amongst an as- 

 semblage of high hills, at an elevation of 2300 feet above the level of 

 the sea. The numerous indications, however, of volcanic action in 

 the neighbourhood of Tagua-tagua afford us a clue to explain the 

 cause by which such alteration of the aspect of the country as has 

 been manifestly produced, must have been occasioned. The fragments 

 of bone which Mr. Bollaert was enabled to discover, consisted of por- 

 tions of a femur and tibia ; those which Don Claudio Gay figures, are 

 the atlas, tibia, calcaneum, fourth metacarpal, and, finally, the almost 

 entire mandible. 



De Blainville is of opinion that evidence is wanting that the Mas- 

 todon A ndium and the Mastodon Humboldtii are different species. 

 Laurillard (D'Orbigny, " Diet. Hist. Nat.," art. Mastodon) denies this 

 theory, and points out that the angle formed by the symphysis in 

 Humboldtii is short, and otherwise differs from the same structure in 

 Andium. I am aware of the fact that Cuvier founded the species 

 Humboldtii upon a specimen alleged to be brought from Con- 

 cepcion by Baron Humboldt, a place never visited by him ; but I 

 am inclined to think that some error or misapprehension exists as 

 to this statement. The Andes at present act as an effectual barrier 

 to prevent the migrations of large species of animals across them, and 

 unless the upholder of the theory that the La Plata and Chile species 

 of Mastodon are of the same species, accepts also the hypothesis of their 

 existence in South America antecedent to the present disposition 

 of the continent and upheaval of the Andes, he cannot hold the 

 possibility of accidental migration of elephants over the snowy range. 

 If, however, both Andium and Humboldtii are modified descendants of 

 some original progenitor, which existed in South America before the 

 upheaval of the Andes, the difficulty in some way disappears. But 

 upon examination of the specimens of Mastodon Andium in the 

 British Museum collection, the habitat from which they are un- 

 doubtedly derived is Buenos Ayres. I have no doubt whatever of 

 the perfect accuracy of Mr. G. R. Waterhouse's statement as to their 

 being geographically derived from that country, and I cannot close 

 my eyes to the fact, that we have here evidence of the existence of 

 Mastodon Andium in a spot in which Laurillard, who so confidently 

 assigned the western side of the Cordilleras as its habitat, never 

 dreamed. 



Are the differences between Andium and Humboldtii of specific 

 value ? I think not. From inspection of a large series of teeth of 

 Mastodon longirostris (angustidens) I can confidently declare that 

 there is not greater difference between the teeth of Andium and 

 Humboldtii than between the many varieties of the narrow-toothed 

 Mastodon. When Cuvier founded the species Humboldtii, he thought 

 that there was a difference of size between the molar teeth of the two 



