EVOLUTION AS A FACT 



481 



same explanation can be given of the tailless condition of the 

 man -like or anthropoid apes (Gorilla, &c.). The troublesome 

 little outgrowth from the intestine familiarly known as the 

 ' 'appendix", which when diseased leads to appendicitis, corre- 

 sponds to what is a large and useful structure in some other 

 Mammals; and a little red fold (semilunar fold) in the inner 

 corner of the eye appears to be the remnant of a third eyelid. 

 And so on, almost indefinitely. Among Mammals other than 



Fig- J 336- (i) and (2), Upper and lower grinding-teeth of a young Duck-Bill (Ornithorhynchus), natural size and 

 enlarged; (3) grinding tooth (enlarged) of an extinct Mesozoic mammal (Microlestes). 



ourselves we find a great variety of vestiges. Whalebone 

 Whales, to take a well-known case, possess neither teeth nor 

 externally visible hind-limbs. But traces of teeth are found in 

 the jaws of very young individuals, although they are never 

 cut. And vestigial hind -limbs are found even in adults, im- 

 bedded in the muscles of the hinder part of the body, exactly 

 where hind-limbs should be were they fully developed. Unless 

 we simply accept these things as inexplicable facts, we must fall 

 back on the doctrine of evolution, and consider such structures 

 as dwindled heritages, reminiscent of earlier conditions. 



Passing from the higher Mammals to their lowest existing 



