56 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



important from the first appearance here of the 

 division of the extremities into five digits. 



14. A Sozurian stage, amphibious and losing the 

 gills in the adult state, but retaining the tail like 

 our Salamanders and Tritons. 



15. A Protamniotic stage, characterized by the 

 disappearance of the gills and the development of 

 an amniotic membrane. This type, entirely hypo- 

 thetical, is justified by the numerous characteristics 

 common to the Reptiles, Birds, and Mammals. 



16. A Promammalian stage, an unknown type, 

 no doubt akin to the present Ornithorhyncus and 

 the Echidna, but having toothed jaws. 



17. A Marsupial stage, superior to the preceding 

 by the division of the cloaca, the formation of 

 breasts and the reduction of the clavicles. The 

 present Sarigues may give an idea of this. 



18. A Prosimian stage, similar to the short- 

 pawed Lemurians, like the Makis ; they are dis- 

 tinguished from the preceding by the development 

 of a placenta and by the loss of the marsupial pouch, 

 as well as the marsupial bones to support it. 



19. A Monocercal stage, similar to the long-tailed 

 Apes of the Old Continent, such as the Semnopitheci ; 

 these forms issued from the Prosimians by the 

 transformation of the teeth and the change of the 

 claws into nails. 



20. An Anthropoid stage, issued from the preced- 

 ing by the loss of the tail, of a portion of the hair 

 and by the development of the skull. None of the 

 existing great Anthropoids exactly represents this 

 vanished type. 



21. A Man- Ape stage, hardly differentiated from 



