462 



EVOLUTION AND ANBIAL LIFE 



unfavorable to the preservation of their remains as fossils in 

 rocks. Of the hundreds of species and millions of individuals 

 of the monkey tribes, very few of their remains are known 

 anywhere. Living in thickets and underbrush there is little 

 opportunity for them to be preserved as fossils. With man, 



Fig. 292. — End of the humerus of various animals including man, showing position of 

 the humerus canals. yl,Hatteria; i?, Lacerta; C, cat; Z), man. (After Wiedersheim.) 



the condition is not very different. Implements of stone, bone, 

 bronze, and iron mark stages in the development of primitive 

 tribes. Fossil remains are confined almost wholly to bones 

 buried in quicksand or in the drippings of caves. Of fossil 

 monkeys, several genera have been described. Pan sivalensis 

 is a species of extinct gorilla from the Pliocene of the Punjaub. 



Of all the fossil primates 

 the one of the greatest 

 interest is Pithecanthropus 

 erectics, from the upper 

 Pliocene of Java, lately 

 described by Dr. Eugene 

 Du Bois. This species 

 has been designated by 

 Haeckel as " the last link " 

 in human genealogy. Its 

 characters have been held 

 to correspond with those 

 of the hypothetical ape- 

 man imagined by Haeckel and named Pithecanthropus alaulus, 

 before these remains were found. The generic name of the 

 imaginary ape-man has been transferred to the actual fossil. 

 The discovered relics of this species are scanty enough, consist- 

 ing of the skullcap, a femiu-, and two teeth (Figs. 294 and 295). 



a. Ps. 



Fig. 293. — The human eye showing, Ps, arrange- 

 ment of the third eyelid, Blica semilunaris. 



