;o6 PRIMATES 



Apes, the Orang has a brain which is most like that of Man ; 

 indeed, it may be said to be like Man's in all respects, save that it 

 is much inferior in size and weight, and that the cerebrum is more 

 symmetrically convoluted and less complicated with secondary and 

 tertiary convolutions. If the brain of Simla be compared with that 

 of Gorilla and Anthropopithecus, we find the height of the cerebrum 

 in front greater in proportion in the former than in the latter ; also 

 the bridging convolutions, though small, are still distinguishable, 

 while they are absent in the Chimpanzee. Nevertheless this 

 character cannot be of much importance, since it reappears in Ateks, 

 while two kinds of the genus Cebus (so closely allied as to have been 

 sometimes treated as one species) differ strangely from each other 

 in this respect. The corpus callosum, in Apes generally, does not 

 extend so far back as in Man, and it is very short in Pithecia. In the 

 Orang and Chimpanzee there are, as in Man, two corpora albicantia, 

 while in the lower Monkeys there is but one. The vermis of the 

 cerebellum is larger in the Cebidce than in the Simiidce and Cerco- 

 pithecidce. In all Apes below the Simiidce each lateral lobe of the 

 cerebellum gives off a small lobule, which is received into a special 

 fossa of the petrous bone. Certain prominences of the medulla 

 oblongata, termed corpora trapezoidea, which are found in lower 

 mammals, begin to make their appearance in the Cebidce." 



The organs connected with the functions of alimentation, circu- 

 lation, and excretion, as well as the muscles, conform generally to 

 the type obtaining in Man, of which full description will be found 

 in works on human anatomy. The tongue is longer in Apes than 

 in Man ; and a uvula is generally present, although rudimentary in 

 the Cebidce. The peculiar sacculation of the stomach in the sub- 

 family Semnopithecince has been already mentioned ; this sacculation 

 is most developed at the cardiac extremity, where it somewhat 

 resembles a colon spirally coiled. In Hylobates the stomach is very 

 like that of Man, differing only in the more elongated and distinct 

 pylorus. Pithecia has a more globular stomach, while in Hapale 

 the cardiac and pyloric apertures are approximated. The intestine 

 of Apes is devoid of valvulae conniventes, and it is only in Man and 

 the Simiidce that the colon is furnished with a vermiform appendage. 

 The colon varies from a fully sacculated form in Hylobates to a 

 smooth one in Cebus. 



The liver of Apes is subject to a considerable amount of varia- 

 tion. In the Simiidce it comes more or less close to the human 

 type ; that of the Orangs being usually divided only into two 

 principal lobes by the umbilical vein, and showing no trace of 

 lateral fissures. In the Gorilla these fissures are present, so as to 

 produce right and left lateral and central lobes. Hylobtites has a 

 liver (Fig. 352) which perhaps is nearer to the human than that of 

 any of the other Simiidce. In the Cercopithecidce the liver differs 



