4^62 Zoological Societi/: Mr. Owen on the 



Chimpanzee with those which had replaced the deciduous teeth in 

 the older specimen. The resemblance in point of size and figure was 

 exact, and left no room for doubt as to the point in question. The 

 succession takes place precisely as in the human subject, but the per- 

 manent teeth, and especially the incisors and canines, are proportion- 

 ally longer. The particulars of their form and arrangement are 

 given at length. 



This portion of the paper was accompanied by an extensive series 

 of admeasurements of the different parts of the skeleton in the adult 

 and young Chimpanzee, compared with those of the young and adult 

 Orang; and was further illustrated by numerous drawings, and by 

 the exhibition of Mr. Walker's skeleton of the Chimpanzee^ lent by 

 him for the purpose. 



The second portion of the paper commences with the remark 

 that the opportunity which the rare and interesting skeleton of the 

 adult Chimpanzee, in the possession of Mr. Walker, had afforded of 

 tracing the changes of structure occurring in that Ape^ in its progress 

 to the adult condition, had induced the author to review the question 

 relative to the identity of the young Simia Satyrus with the great 

 Pongo of Borneo, formerly brought by him under the notice of the 

 Society (Phil. Mag. and Annals, N.S., vol. ix, p. 60,) and to consider 

 the osteological structure of the latter, or adult Orang, with reference 

 to that of its less powerful and more anthropoid congener, the Chim- 

 panzee. This comparison would show that the number and value 

 of the points of resemblance, or of approximation, to the Bimanous 

 structure are in favour of the Chimpanzee ; although in this, as 

 in most other instances, there are some particulars of its organiza- 

 tion indicative of a more marked relation with the inferior forms of 

 the group than with those which rank immediately below it*. 



In common with the skull of the Mandrill that of the adult Orang 

 is remarkable for its flattened occiput^ formidable canine teeth, huge 

 jaws, widely expanded zygomatic arches, .and strongly developed 

 cranial ridges; but it exhibits a marked distinction in its less brutalized 

 expression, resulting from the more perpendicular slope of the face, 

 the absence of the projecting supraciliary ridges, the greater expan- 

 sion of the cerebral cavity, and the non-development of the supra- 

 maxillary ridges. Its cranium is less flattened at the vertex than that 

 of the Chimpanzee; and but little exceeds in capacity that of the young 

 at the period of acquiring its first permanent molares, the increase 

 in size being chiefly dependent on the thickening of the walls of the 

 skull. The ridges which circumscribe on the frontal bone the origin 

 of the temporal muscles inclose a triangular space, the smoothness 

 of which strongly contrasts with the irregular surface of the re- 

 mainder of the cranium ; and the interparietal crest rises, as in 

 the Hycena and other Carnivora, high above the general level. The 

 situation of these ridges, with reference to the sutures, is only de- 

 terminable by comparing the faint commencement of their growth 

 in the young animal, very few traces of the sutures remaining in the 



• Do not these facts indicate the existence of a tendency towards a cir- 

 'cular succession of affinities in the group formed by the Simicv ? — E. W. B. 



