THE MAN-LIKE APES. I47 



all the principal sulci [or grooves] appear, the pattern according 

 to which they are arranged is identical with that of the corre- 

 sponding sulci of Man. The surface of the brain of a Monkey 

 exhibits a sort of skeleton map of Man's, and in the Man-like 

 Apes the details become more and more filled in, until it i? 

 only in minor characters, such as the greater excavation of the 

 anterior lobes, the constant presence of fissures usually absent 

 in Man, and the different disposition and proportions of some 

 convolutions, that the Chimpanzee's or the Orang's brain can 

 be structurally distinguished from Man's. . . . And the 

 difference between the brains of the Chimpanzee and of Man 

 is almost insignificant when compared with that between the 

 Chimpanzee's brain and that of a Lemur." {Huxley?) 



The Anthropoid Apes have no cheek-pouches. The larynx 

 has large dilatations of the shallow depressions — called ventricles 

 — of the mucous membrane on each side of its inner surface — 

 which may extend down as far as the arm-pits, and be con- 

 nected with powerful voice possessed in most of the species. 

 The stomach is simple, like that of Man, and not sacculated, 

 as in the last family (the CercopithecidcB). 



The uterus and other structures connected with the repro- 

 ductive system resemble those in the human subject. The 

 length of gestation varies probably in the different genera, and 

 is unknown in many of the species. The period for which the 

 young are suckled by the mother lasts about six months. 

 "The proportions of the limbs to one another and to the 

 body do not sensibly change after birth ; but the body, limbs, 

 and jaws enlarge to a much greater extent than the brain-case." 

 (^Huxley) Observations are still required, in regard to most 

 of the species, as to the age at which they arrive at maturity, 

 and are able to reproduce. 



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