14 MAMMALIA— ORDER I.— PRIMATES. 



of small bones of which that joint is composed. What may be the object of 

 the disappearance of this bone, it is riot easy to say ; but the fact that it is 

 wanting in the two genera of apes just mentioned is very significant of their 

 close structural affinity with man. In one respect the man-like apes stand 

 apart both from the human and tlie monkey type, namely, in the great 

 relative length of the arms as compared with the legs, the disproportion 

 being most strongly marked in the gibbons, which are actually able to 

 walk in the upright posture with their bent knuckles touching the ground. 



So far, indeed, as their bodily structure is concerned, the man-like apes 

 seem undoubtedly more nearly related to man than they are to the lower 

 monkeys ; and they constitute a family {Simiidce) by themselves, which may 

 be regarded as intermediate between the one (Cercopithecidce) including the 

 lower monkeys, and that represented by man himself.- While at present the 

 " missing link " between man and the apes is wanting, extinct forms tend to 

 connect the latter very closely with the monkeys. For instance, a fossil ape 

 (Dryopithecus) from the Miocene Tertiary strata of France has the bony 

 union between the two branches of the lower jaw much longer than in any 

 existing man-like ape, although it is approached in this respect by the gorilla; 

 while from the corresponding beds of Italy another extinct form {Oreopithecus) 

 appears to be in great part intermediate between the man-like apes and the 

 lower monkeys. 



The present distribution of the anthropoid apes clearly points to the exist- 

 ing species being the last survivors of a group which was once widely spread 

 over the Old World, when warmer climatic conditions prevailed over what we 

 now call the temperate regions. The gorilla, for instance, is confined to 

 Western Equatorial Africa ; where it is accompanied by the two species of 

 chimpanzee, one of which ranges eastwards across the continent as far as 

 Uganda. The orangs, of which there are probably two species, on the other 

 hand, are confined to the great islands of Sumatra and Borneo ; while the 

 numerous species of gibbons have a wide range in South-Eastern Asia, attain- 

 ing their maximum development in the Malayan Archipelago and the adjacent 

 regions. This distribution is remarkably discontinuous, but the little known 

 of the past history of the group tends somewhat to consolidate the present 

 scattered distributional areas. For instance, a chimpanzee once inhabited 

 Northern India ; while it is most probable that an orang also was a contem- 

 poraneous dweller in the same country. This suggests that Imlia may have 

 been the original home of the larger man-like apes, from whence the chim- 

 panzees and gorillas migrated south-westwards to Equatorial Africa, while the 

 orangs travelled in an easterly direction to find a last home in the tropical 

 islands to which they are now confined. 



Of the four existing genera of the man-like apes, the chimpanzees (Anthro- 



popithecus) are those which come nearest to man, this being especially shown 



by the shortness of the bony union between the two branches 



Chimpanzees otthelower jaw, the form and mode of arrangementof the teeth 



[Anlhropopilhe- (especially in the young), the relatively small development of 



CMS). the tusks of the male, the absence of the enormous bony 



crests on the skull so characteristic of the gorilla, and the 



slight difference in the size of the two .exes. The chimpanzees and the 



gorilla alone resemble man in having seventeen vertebras between the neck 



and the sacrum, and likewise in the absence of the central bone in the wrist, 



although they differ in the comparatively unimportant feature of possessing 



an additional pair of ribs. It will be unnecessary to give a full description of 



