XXIX 



ELEPHANTS AND RELATED FORMS 



1. 'Near-ungulates', superorder Paenungulata 



From the Palaeocene ungulate stock, when it was yet hardly differ- 

 entiated from that of other mammals, there diverged several lines of 

 herbivorous animals and these rapidly increased and diversified in the 

 Eocene, many of them becoming very large. Most of these lines 

 declined in the Oligocene and only the huge elephants and tiny 

 hyraxes remain today to show approximately the structure of this 

 range of Eocene pantodonts, dinocerates, and other forms. The highly 

 specialized Sirenia (sea-cows) were also an early offshoot of this type 

 of animal. The various lines diverged so very long ago that we should 

 hardly expect to find that they have much in common that they do not 

 share with other ungulates, or indeed with all mammals, but it has 

 long been recognized that there is a loose grouping of orders around 

 the elephants and hyraxes. Simpson suggests the name Paenungulata 

 ('near ungulates') for these forms that are all slightly, but not much, 

 beyond the protoungulate level. The legs of all of them remain rather 

 primitive, with long upper segments, complete ulna and fibula, and 

 several digits, and without well-marked hoofs. The incisors and 

 canines often become reduced to single pairs of large tusks in each 

 jaw and the molars are specialized for grinding, with the development 

 of cross-ridges. 



2. Classification 



Superorder 3. Paenungulata 

 Order 1. Hyracoidea. Oligocene-Recent. Palearctic, Africa 

 Procavia (= Hyrax), hyrax, Africa, Asia 



Order 2. Proboscidea. Eocene-Recent 



# Family 1. Moeritheriidae. Eocene-Oligocene. Africa 



*Moeriiherium 

 *Family 2. Deinotheriidae. Miocene-Pleistocene. Eurasia, Africa 



*Deinotherium 

 *Family 3. Gomphotheriidae. Oligocene-Pleistocene. Holarctic, 

 S. America, Africa 

 *Palaeomastodon, Lower Oligocene, Africa; *Phiomia, Oligo- 

 cene, Africa; *Gomphotherium (= *Trilophodon), Miocene- 



