MAMMALIA SIMI.E. 15 



of man in capability, a fact, indeed, known even to Galen. With respect to 

 the difference between the Monkeys of the Old and those of the New World, 

 I have found a character in the conformation of the osseous external audi- 

 tory canal, which distinguishes these two families from each other more pre- 

 cisely than all the other characters. 



SIMI.E CISATLANTIC^:. Is. Geoffrey persists in regarding 

 his Pitkecus bicolor as a 'distinct species. (1. c. p. 526.) 



I repeat the declaration I made last year, that a new species cannot be 

 erected with certainty from a single young animal, whose colour and the form 

 of whose cranium change considerably with age. I look upon it as super- 

 fluous to enter more particularly into the critical remarks which Is. Geoffrey 

 makes upon the descriptions that have hitherto been given of the Ourang- 

 outang, since he does not appear to be acquainted with Salomon Miillcr's 

 and Schlcgel's labours on that subject, nor with those of Heusinger and 

 myself. 



J. Macartney. On the minute structure of the Brain 

 in the Chimpanzee and of the human Idiot, compared with 

 that of the perfect Brain of Man. (Transactions of the 

 Royal Irish Academy, xix, 2. Dublin., 1843). 



A comparison of the brain of the Chimpanzee with those of two idiots, 

 whence it appears that the brains of the latter presented a still lower 

 degree of organization than that of the brute. Of the brain of the 



O O 



Chimpanzee, the author moreover says, that "the external form has so 

 close a resemblance with that of the human brain, that, excepting the 

 difference of size, the one might be confounded with the other. The convo- 

 lutions were just as distinctly marked, and the proportion of the cerebellum 

 to the cerebrum exactly as in man." The corpora caudicautia were very ill 

 defined ; the corpora pyramidalia and olivaria not much developed ; the 

 branches of the arbor vita? perhaps not so distinct, but equally numerous as 

 in man. The dentated margin of the corpus fimbriatum was wanting ; the 

 pineal gland large. The anterior pair of the corpora quadrigerniua the 

 smaller, &c. Figures are given of the brain of the Chimpanzee and of an 

 idiot. 



Is. Geoffrey has made several contributions to a know- 

 ledge of the Gibbons. 



Hylobatcs entelloides has been described at length by him, both in Jacque- 

 mont's 'Voyage dans 1'Inde' (46, 47 livrais. 1843, p. 13), and in the 'Archiv. 

 du Mus.' (ii, p. 532), and in the latter place a beautiful figure (tab. 1) is given. 

 From the light-coloured varieties of H. albimanus it is distinguished (a) by 





