APES AND MONKEYS. 



sideration. With the exception of the Arcto- 

 pitheci the digits in all Simiae have flat nails, 

 which, however, in some species become more 

 arched, and so pass into claws. 



We are justified in saying that the Simiae 

 have four hands, while man has only two. 

 In the former, as in all climbing animals, the 

 hind-limbs are developed chiefly as grasping 

 organs, in man only the fore-limbs. This 

 essential difference goes so far that the Colobi 

 in the Old World and the spider-monkeys 

 (Ateles) in the New have no thumbs at all, 

 accordingly no hands in the ordinary sense, 

 and the Arctopitheci have indeed a thumb 

 but not an opposable one. 



All this is true enough, but when we go to 

 the bottom of the matter, these seemingly 

 far-reaching distinctions become shorn of much 

 of their importance. In relation to function, 

 indeed, they could not be greater than they 

 are. In man the hind-limbs are only organs 

 of support and locomotion, the fore-limbs 

 solely of prehension and touch. In the Simiae 

 these functions separated in man are distri- 

 buted among all the four limbs. 



Nevertheless, except as regards the motions 

 of hallux and pollex, the structure of the two 

 extremities is the same in the Simiae as in 

 man. The hinder extremity of the former is a 

 foot adapted for grasping indeed, yet entirely 

 similar in its structure to the foot of man. 



The human foot is distinguished from the 

 hand chiefly by the shortness of the toes, the 

 development of the heel and structure of the 

 ankle generally, and the position of the foot 

 with reference to the leg. The leg stands 

 perpendicularly over the ankle, which has 

 developed a posterior process, the heel. The 

 hand is continuous in direction with the fore- 

 arm, and has no heel; the articular surface 

 which connects it with the arm is not found 

 as in the foot on the back but at the end 

 turned towards the body. 



In all these respects the hind-foot in the 

 Simiae resembles the human foot. There is 

 always a projecting heel, and therefore an 



ape's or monkey's foot can no more be brought 

 into the same line with the leg than the 

 human foot can; the two must always form 

 an angle with one another. 



The posterior "hand" of the Simiae can 

 never accordingly be compared anatomically 

 with the human hand, but only with the 

 human foot. Its ankle is identical in structure 

 with that of a man, so much so that in the 

 gorilla only very insignificant differences can 

 be detected. The hand proper in the Simiae, 

 on the contrary, is constructed exactly like 

 that of man, and even the absence of the 

 thumb in many forms constitutes no essential 

 difference. 



And this nasty tail ! Much paper would 

 have remained unsoiled if the authors of 

 certain controversial writings had known that 

 the anthropoid apes have no tail, but on the 

 contrary have a vertebral column terminating 

 exactly as in man. But it would appear 

 that in many circles it is impossible even to 

 think of a monkey without a tail, and that 

 involuntarily Cercopitheci and Semnopitheci 

 are taken as the sole representatives of an 

 order in which this appendage to the vertebral 

 column undergoes all possible modifications, 

 from the prehensile and tactile organ of the 

 howling monkeys to the rudiment at the end 

 of the vertebral column of the anthropoid apes. 



With respect to internal organs only a few 

 differences, and these not general, can be 

 pointed out, such, for example, as cheek- 

 pouches, bladder or drum-like organs for 

 increasing the loudness of the voice, the 

 constricted stomach in the Semnopitheci, and 

 similar peculiarities which are not of much 

 account. The human type is prominent 

 everywhere, and quite peculiarly so in what 

 belongs to the reproductive organs. The 

 Simiae never have more than two pectoral 

 mammae; the envelopes of the ovum are 

 exactly of the same nature as in man, and the 

 placenta, like the human one, is discoidal, in 

 many cases simple, but in others divided by 

 a fissure into two lobes. 



