118 ANIMAL LIFE AND HUMAN PROGRESS 



condition of these sublingual folds in the great divisions of the 

 Primates would seem to point to the fact that the point of 

 departure of the Platyrrhini and Catarrhini must have been 

 from some very early form in which both folds were present 

 as they are in Man, the chimpanzee and Tarsius. 



Strong confirmation of the evolution of Man via the system- 

 atic chain of the whole of the Primates is held to be evinced 

 in the well-known condition of the human appendix caeci. 

 The human caecum and appendix show a very striking likeness 

 to the same structures in the gorilla, chimpanzee and orang 

 utan, and this condition is usually regarded as being one of 

 reduction and atrophy from the much larger organ of the 

 monkeys and lemurs. The many considerations of diet, and 

 the general uncertainty as to the precise nature and function 

 of this portion of the bowel, render dogmatism in any direction 

 a risky thing. Perhaps we do not know what the primitive 

 picture of the mammalian appendix caeci is like, but at any 

 rate we can make a comparison of the human condition with 

 that seen in the Ornithorhynchus and Echidna. Here, again, 

 we are faced with the remarkable fact that the similarity 

 between the highest mammal and the lowest is very great, 

 and, more than this, the appendix of Man is almost exactly 

 paralleled in the Marsupial Wombat (Phascolomys), though it 

 differs so remarkably from anything seen in the monkeys 

 either of the Old World or the New. 



The human kidney differs markedly from the type common 

 to all the Old World monkeys and anthropoid apes, although 

 at times the gorilla varies somewhat in the human direction. 

 The New World monkeys, though differing from the Old 

 World monkeys and Man in so many basal features, yet 

 possess a kidney that is constructed definitely upon human 

 lines. 



In the reproductive system the presence of the hymen has 

 been claimed from the very earliest times as a human distinc- 

 tion a distinction which separated Homo not only from apes 

 and monkeys, but from all the mammals. It is a distinction 

 that one who insisted upon distinctions would be ready enough 

 to claim but for the knowledge that a hymen is, in all prob- 



