28 



Coelodon, Ocholherium^ Gnathopis, Lestodon, Scelidotherium^ and 

 Sphcenodon ; and among the Armadilloes were Chlamydotlierium^ 

 Earydon^ GlyjJtodon, Heterodon, Pacliytheriuvi and Scliistopleurum.. 

 Glossotheriuni, another extinct genus, is supposed to be allied 

 to the Ant-eaters. 



It is frequently asserted, and very generally believed, that the 

 larsre number of husfe Edentata which lived in North America 

 during the Post-Pliocene, were the results of an extensive 

 migration from South America soon after the elevation of 

 the Isthmus of Panama, near the close of the Tertiary. No 

 conclusive proof of such migration has been offered, and 

 the evidence, it seems to me, so far as we now have it, is 

 directly opposed to this view. No undoubted Tertiary Edentates 

 have j-et been discovered in South America, while we have at 

 least two species in our Miocene, and during the deposition of 

 our lower Pliocene, large individuals of this group were not 

 uncommon as far north as the forty-third parallel of latitude, 

 on both sides of the Rocky Mountains. In view of these facts, 

 and others which I shall lay before you, it seems more natural 

 to conclude from our present knowledge, that the migration, 

 which no doubt took place, was from north to south. The 

 Edentates finding thus in South America a congenial liome 

 flourished greatly for a time, and although the larger forms are 

 now all extinct, diminutive representatives of the group still 

 inhabit the same region. 



The Cetacea first appear in the Eocene, as in Europe, and 

 are comparatively abundant in deposits of this age on the 

 Atlantic Coast. The most interesting remains of this order, yet 

 found, belong to the Zeuglodontidce^ which are carnivorous 

 whales, and the only animals of the order with teeth implanted 

 by two roots. The principal genera of this family are Zeuglodon 

 and Squalodon, the former genus being represented by gigantic 

 forms, some of which were seventy feet in length. The genus 

 Saurocetes, which includes some small animals of this group, has 

 been found in South America. The Dolphin family {Delphini- 

 dee) are well represented in the Miocene, both on the Atlantic 



