240 DIVERSIONS OF A NATURALIST 



were, a couple of hundred years ago, cited with wonder 

 and head-shakings as a proof that there was, after all, a 

 real similarity in man's structure to that of animals, and 

 pictures of the " Homo caudatus," or tailed man, were to 

 be found in ancient books dealing with marvels and 

 mysteries. As a matter of fact, three or four small 

 insignificant vertebrae, almost immovable, are always 

 present in man attached to the great bone called the 

 sacrum, formed by the union of five vertebrae. These 

 small vertebrae, to which the name " coccyx " is applied, 

 are sunk beneath the skin and fat, at the end of the 

 backbone, and though they correspond to bones of the 

 tail of other animals, they are, in normal mankind, thus 

 concealed from view. Precisely the same atrophy and 

 concealment of the bones of the tail is found in the 

 gorilla, chimpanzee, orang, and gibbons. They are all 

 of them, seen in the flesh, as tail-less as man is, and seen 

 in skeleton have precisely the same number of minute 

 tail bones forming a " coccyx." This is true not only of 

 the higher apes mentioned, but of the Barbary ape — 

 which lives at Gibraltar — whilst others, such as the 

 mandrill, have very short tails. In fact, the tail is a 

 very variable appendage in monkeys, and, as the Manx 

 breed shows, also in cats. It is mainly " decorative " in 

 the old-world monkeys, and is probably maintained by 

 sexual selection. It is only in the new-world monkeys 

 that it has acquired obvious mechanical value. In them 

 it is prehensile, and is used with great effect in swinging 

 among the trees from branch to branch, whilst the 

 hands and feet are left free to grasp any new support. 



Another feature which is commonly, but erroneously, 

 supposed to constitute a great difference between man 

 and apes is the hairiness of the latter. This is only a 

 difference of degree, for the whole surface of the body of 



