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[July, 



NOTES AND CORRESPONDENCE. 



On the Cerebrum of the Entellus Monkey. (Semnopithecus Entellus). 

 By E. Ray Lankester. 



The important discussions which 

 have been going on during the last 

 two or three years, relative to the 

 comparative relations of the brains 

 of man and the higher monkeys, 

 have excited so much interest, that 

 a few remarks on the cerebral con- 

 formation of an animal holding a 

 comparatively high position in the 

 quadrumanous series, may not be 

 altogether unacceptable to the read- 

 ers of this Journal. 



About a year since, I received 

 from the menagerie of the Zoologi- 

 cal Society, by the kindness of the 

 secretary, the Entellus monkey, 

 which had recently died. With re- 

 gard to the anatomy of the other 

 parts of the body, no mention need 

 be made ; the brain was carefully ex- 

 posed by removing the calvarium, 

 and drawings and observations were 

 made. It was then placed inspirits 

 and allowed to harden for several 

 months. The following description 

 of the cerebrum of the Entellus is 

 given from careful examination of 

 this specimen ; at the same time, I 

 would distinctly state that in all 

 material points as well as matters 

 of detail, I have only to confirm the 

 observations of that accurate and 

 lamented anatomist, M. Pierre Gra- 

 tiolet. I have, however, been able 

 to make an examination of the in- 

 ternal modifications of structure in 

 the brain of Semnopithecus, which 

 M. Gratiolet did not consider him- 

 self justified in doing with the few 

 specimens preserved in the Museum 

 of the Jardin des Plantes. 



From a careful study of the form 

 and arrangement of the cerebral 

 folds and convolutions in the higher 



quadrumana, M. Gratiolet came 

 to the conclusion that the Orang, 

 the Chimpanzee, and probably also 

 the Gorilla, were almost equally 

 closely related to man, and that 

 they each formed the culminating 

 point of a series having more or 

 less the same peculiarities in brain 

 structure. Beneath the Orang are 

 placed the Gibbons (Hylobates), 

 followed by the Semnopitheci and 

 Cercopitheci, the series thus merg- 

 ing into the smaller monkeys ; 

 with the Chimpanzee, in the same 

 way, he associates the Macaci, 

 Rhesus, and Magots, while he con- 

 jectures that the Gorilla would 

 form the highest development of a 

 similar series, including the Baboons 

 (Cynocephali, &c.) It will be seen, 

 therefore, that the brain of the Sem- 

 nopithecus is only three degrees 

 removed from that of man, and holds 

 a position intermediate between 

 that of the Gibbons and the Cerco- 

 pitheci. The truth of M. Gratio- 

 let's propositions with regard to the 

 three types of arrangement of the 

 cerebral convolutions cannot be 

 doubted by any one who examines 

 his drawings ; it would no doubt be 

 interesting to follow out his line of 

 argument, and to see on what 

 grounds the brain of the Semno- 

 pithecus has this position assigned 

 to it ; but all that I can here do is 

 to examine whether the specimen 

 about to be described furnishes any 

 additional evidence of value by the 

 characters of its internal structure 

 or external conformation, tending to 

 confirm M. Gratiolet's statements. 



The general form of the brain of 

 the Entellus, as seen in Fig. 1, is 



