92 THE LESSON or EVOLUTION 



the Pliocene. The sheep is of a very late origin, and 

 is hardly known in the fossil condition. Pithecan- 

 thropus erectus, of the pliocene of Java, was a form 

 intermediate between man and the apes (gibbon ?). 

 It was an ape-like man, which walked erect. But 

 there is not much difference in structure between man 

 and the higher apes. The bones and muscles in both 

 are the same ; the differences between them being 

 chiefly due to adaptations necessary to enable man to 

 stand upright, and to use his legs alone for locomo- 

 tion. Man, like the apes, has several vestigial organs 

 which are of no use to him, but which are well de- 

 veloped and useful in other animals. Among these 

 are the remains of a third eye-lid, as well as muscles 

 for moving the ears and the tail. Several other 

 muscles, which are always found in the lower animals, 

 but which are generally absent in man, are occasionally 

 developed in him ; and it is chiefly the presence of 

 these vestigial and useless structures which has con- 

 vinced naturalists that man has a common origin with 

 other mammals. 



It is a mistake to think that man was the last 

 species of mammal to appear on the earth. He 

 certainly dates from the Pliocene; while several animals, 

 including the sheep, are not known to be older than 

 the Pleistocene. 



The oldest known human skeletons are those of 

 the Neanderthal and Spy caverns. They belong to 

 what is known as the Neanderthal Eace, and are of 

 Pleistocene age. The skulls have strong ridges over the 

 eyes, a retreating forehead, and also a retreating chin. 

 At that time Palaeolithic man appears as a savage, 

 living in caves and hunting wild animals, which he 



