312 TOWARDS THE HUMAN FORM 



Palaeotheridae and other Perissodactyla as well as Lemurs 

 now no longer seen except in India, South Africa, and 

 Madagascar. This fauna, known as the Notostylops fauna, is 

 followed by two others preserved in the clays mixed with 

 volcanic ash which are found in the neighbourhood of the 

 gulf of Saint-Georges. To the preceding Mammalian groups 

 we must add other later precursors of the Proboscidians, 

 such as Promcerytherium and Pyrotherium, large animals 

 studied by Albert Gaudry, whose molars with transverse ridges 

 recall those of Rodents and Elephants, and whose lower jaw 

 carries two long almost horizontal incisors. In this collection 

 there is no trace of the Bats, Creodonta, Carnivora, and 

 Artiodactyla, all of which already existed in North America, 

 but, on the other hand, it includes Sparassodontia, Edentata, 

 Typotherium, and Toxodontia which specifically belong to it, 

 while its Perissodactyla are of a particular type. They were 

 represented by Macrauchenia, so named because of its 

 long neck, and by forms which approximated to the Equidse, 

 but were quite different from those of North America. 



This curious South American fauna is less astonishing than 

 that discovered twenty years ago in the Fayum of Egypt, and 

 belonging to the Middle Eocene. The oldest zone, that of 

 Birket-el-Querun, is still marine, but it already contains 

 Zenglodon, found also in Alabama and New Zealand, and some 

 related forms, 1 which supposes a long anterior existence for 

 the aquatic Carnivora like the Seals. The Middle Zone, that of 

 Kasr-el-Sagha, contains, in addition to Crocodiles, Turtles, 

 Snakes, and Cetacea, one of the oldest Sirenidans known, 2 a 

 mammal whose position is doubtful, Baryiherium graui and 

 Mceritkerium lyonsi. In the 300 metres depth of strata com- 

 prising the third zone, to whose formation the sea and a large 

 river have contributed, there are entombed innumerable 

 fragments of Mammalian bones. 



Three things have rendered the Fayum fauna especially 

 remarkable : first the existence of the monstrous 

 Arsinoetherium, second that of Mceritherium, Palceomastodon, 

 and Tetrabelodon, ancestors of the Elephants (p. 300), and third 

 the existence of a group of Monkeys, some of which to-day are 

 exclusively American, while others belong to the Old World. 

 The simultaneous presence of these groups of monkeys 



1 Isis, Prozeuglodon, Eocetus. 2 Eosiren. 



