September 13, 1907] 



SCIENCE 



351 



not the case in the southern hemisphere. The 

 fauna of Casarmagu (or of Cerro Negro) 

 is related to that of Torrejon and Puerco, 

 ahout which the scientists of the United States 

 have made some remarkable revelations, and 

 also bears a resemblance to the fauna of de 

 Cemay near Reims, discovered by the late 

 Dr. Lemoine. The fauna of later epochs, the 

 Deseado, Coli-Huapi, Santa Cruzian and 

 Pampean, has not a single genus comparable 

 to those on our hemisphere, and shows an 

 arrest in the development. No mammal has 

 become a paridigitate pachyderm, a ruminant, 

 a soliped like ours, a proboscidian, a placental 

 carnivore or an anthropoid ape. To be sure, 

 the bones are homologous and many of them 

 resemble the bones of our animals. But the 

 association of the characters is very different. 

 For example, in Pyrotherium the hind 

 quarters resemble those of proboscidians, but 

 the forelegs show an entirely different attitude. 

 In limb structure Asirapotherium recalls the 

 dinoceros of the United States, but its denti- 

 tion is different. Colpodon and Nesodon differ 

 less in their dentition from our Ungulata than 

 from other animals, but they have carnivore 

 limbs and their tridactyl hind foot is 

 plantigrade. The gigantic Homalodontherium 

 shows still better the association of ungulate 

 and carnivore <;haracters. Many more ex- 

 amples could be given showing to what extent 

 the fossil mammals of South America are 

 specialized and how little they resemble in 

 appearance the fauna of the northern hemis- 

 phere. 



This statement is of considerable impor- 

 tance to explorers of the antarctic world. 

 When the Institute of France commissioned 

 some of its members to collect information 

 for the next voyage of Dr. Jean Charcot, I 

 published a note in which I pointed out what 

 they might expect to discover in Antarctica, 

 judging from what we know of the paleon- 

 tology of South America.^ 



I noted that the existence of the various 



"Institut de France, Aeadfimie des sciences, 

 " Instructions pour rExpgdition antaretique or- 

 ganist par le Dr. Jean. Charcot. Paleeontologie," 

 par Albert Gaudry, p. 19, 1907. 



large animals of Patagonia can not be ac- 

 counted for in conditions analogous to the 

 actual ones. In the Eocene period, the 

 Deseado has powerful quadrupeds : Pyrothe- 

 rium, Asirapotherium, Homalodontherium, 

 Colpodon, Palceopeltis and many other herbi- 

 vorous genera. This presupposes a luxuriant 

 vegetation and hence a degree of warmth 

 which is in marked contrast to the present cold 

 climate. Furthermore, it presupposes an ex- 

 tent of territory very different from the 

 present narrow space of Patagonia; for it is 

 an admitted fact in zoology that the size of 

 mammals is in direct proportion to that of 

 their habitat. The fauna of Deseado and of 

 Coli-Huapi, which came immediately after, 

 can not be explained unless Patagonia is the 

 remnant of a vast antarctic continent. 



In the Miocene period appeared the fauna 

 of the Santa Cruzien with its quantities of 

 large Nesodon, Astropoiherium, Homalodon- 

 therium, diversified Edentates and so forth. 

 It is equally impossible to understand this 

 fauna if it did not live on an antarctic con- 

 tinent. 



In the period of the Pampas the terrestrial 

 fauna became more powerful than all the 

 former ones. Megatherium, Mylodon, Lesto- 

 don, Scelidotherium, Glyptodon, Toxodon and 

 Macrauchenia in life size must have con- 

 stituted one of the most imposing sights in 

 the history of the world. This fauna is the 

 most difficult of all to account for, if it did 

 not live on an immense antarctic continent 

 with a rich vegetation and warm climate. 

 Since South America is only 1,000 kilometers 

 from Antarctica, it is improbable that this 

 region was at that time under ice and sub- 

 merged. In his report of the expedition of 

 the Belgica, Mr. Cook has written : " The 

 Soundings taJcen tetween South America and 

 the South Shetlands and those made in Ant- 

 arctica show clearly the existence of a con- 

 tinental plateau.'" 



Hence a determination of the age of the 

 Pampas is of great importance for a closer 

 knowledge of the antarctic continent; this 



^ Cook, " Kis le Pole Slid, Expedition de la 

 Belgica," 1897-9, p. 8. 



