154 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 



that of the lower kinds of quadrumanous animals from which these 

 higher representatives of the group have descended. For at a certain 

 stage of embryonic life the tail, both of apes and of human beings, is 



Fig. 27. — Appendix vermiformis in orang and in man, //, ilium; Co, colon; 

 C, coecum; [F, a window cut in the wall of the coecum; ^a;^;, the appendix. {From 

 Romanes.) 



Man 

 F(ETAL 



Fig. 28. — The same, showing variation in the orang. {From Romanes.) 



actually longer than the legs (see Fig. 25). And at this stage of 

 development, also, the tail admits of being moved by muscles which 

 later on dwindle away. Occasionally, however, these muscles persist, 

 and are then described by anatomists as abnormalities. The illustra- 



