1861.] prof. huxley on the brain of ateles paniscus. 24/ 



Doris pulchra. 



Animal soft, oblong-elongate, obtusely rounded in front, and acutely 

 behind ; dorsal region convexly rounded ; margins thin and depressed, 

 slightly undulated, behind the tentacles slightly contracted ; branchiae 

 small, suberect, eight or nine in number, smaller posteriorly ; plu- 

 mule linear, tapering to a point, subquadrangular, compressed, the 

 compressed sides finely and closely lamellated, united at base, and 

 retractile into a common simple cavity ; vent-tube suberect and pro- 

 minent ; dorsal tentacles rather large, oblong ovate, finely and closely 

 obliquely lamellated, and retractile into simple cavities ; labial ap- 

 pendages small, cylindrically tapering ; foot long, narrow, projecting 

 considerably beyond the mantle, acutely rounded behind, and obtusely 

 in front. Colour white, reticulated with orange-yellow and violet- 

 brown lines ; mantle edged with violet, upper half of tentacles violet, 

 branchial plumes edged with violet ; colour beneath the mantle same 

 as above ; upper surface of the foot has a submarginal irregular orange 

 band. The colour of the reticulations on the mantle varies. 



7. On the Brain of Ateles paniscus. By Thomas H. 

 Huxley, F.R.S.,V.P.Z.S., Professor of Natural History 

 IN the Government School of Mines. 



(Plate XXIX.) 



The brain of a Spider Monkey {Ateles belzebuth) has already 

 been partially described and figured by M. Gratiolet in his remark- 

 able memoir ' Sur les Plis Cerebraux des Primates ' (1854) ; but this 

 careful observer had only old spirit specimens at his disposal, and it 

 did not enter into his plan to give any account, either of the internal 

 structure of the cerebrum, or of its relations to the cerebellum, or of 

 the cerebellum itself. Hence a new description, which should touch 

 upon these points, could hardly be superfluous, under any circum- 

 stances ; while, at the present moment, the controversy which has 

 arisen respecting the nature and the extent of the differences in cere- 

 bral structure between Man and the Apes gives an especial value to 

 all new facts. 



It has been affirmed — and a proposed new classification of the 

 Mammalia has been largely based upon the assertion — that the brain 

 of Man is distinguished from that of all Apes by possessing a posterior 

 lobe, a posterior cornu to the lateral ventricle, and a hippocampus 

 minor — these structures being absent in all Apes, even the highest*. 



I have elsewhere t exposed the fallacy of these distinctions as ap- 

 pHed to the Apes in general; Dr. A. T. Thomson J and Dr. Rol- 

 leston§ have proved the existence of the three structures referred to 

 in the Chimpanzee and the Orang, by investigations upon the brains 



* Prof. Owen " On the Classification, &c. of the Class Mammalia," Proc. of 

 Linuean Society, 1857 ; Reade's Lecture, 1859 ; Athenseum, March 23, 1861. 

 t Natural History Review, No. 1, January 1861 ; Athenaeum, April 13th, 1861. 

 t Nat. Hist. Review, No. 1, January 1861. 

 § Nat. Hist. Review, No. 2, 1861. 



