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Show 312 MR. W. L. H. DUCKWORTH O N [Mar. 7> In 9 adult female Chimpanzees, on the other hand, in only one the temporal ridges united to form a slight crest: the average distance between them is 22 mm. These ridges in the male Gorilla reach the sagittal suture as the canine teeth cut and fuse into a ridge, which continues to grow all through life. In the male Chimpanzee they only occasionally unite to form a ridge. The development of the temporal ridges, the height to which they reach on the roof of the skull, depends on the dentition. The condition in the adult female Chimpanzee corresponds to the stage of development found in a male Gorilla cutting its second molar tooth. The lower jaw in the female Gorilla, almost without exception, exceeds in every dimension that of the female Chimpanzee. 11. Summary. The Gorilla may be distinguished in life from the Chimpanzee by its sullen, untamable, ferocious nature ; its long nasal bones descending far below the level of the infra-orbital margin; its great alar nasal folds running to the margin of the upper lip; its great peculiar molar, premolar, and canine teeth; its broad, short, thick Avebbed bands and feet; its long heel and the great length of its upper arm with the smaller development of the forearm. EXPLANATION OF PLATE XX. Anthropopithecus troylodytes kooloo-kamba. Taken from the specimen named "Johanna," living in the collection of Messrs. Barnum and Bailey. 2. Further Note on Specific Differences in the Anthropoid Apes. By W . L. H. D U C K W O R T H , M.A., Fellow of Jesus College, Cambridge. [Received March 4, 1899.] 1. After reading a note on this subject to this Society in December 1898, I learned that in the Zoological Museum at Jena is an Ape, the determination of whose species has given rise to some discussion: the point in dispute being, whether it should be described as a Gorilla or a Chimpanzee. Through the kindness of Brofessor Haeckel I have been enabled to examine the specimen and have arrived at the following conclusion--that, although labelled " Junger weiblicher Gorilla," * neither the stuffed skin nor the skeleton afford any evidence to justify the term Gorilla; and the facts that hardly a suture remains unclosed in the skull, that every epiphysis has long been fused Avith its diaphysis in the limb-bones, and that the teeth are much worn down, indicate that this was an aged, and not a young female. The average transverse diameter of the crowns of the molar teeth is 9*7 m m . (cf. the ape " A." at Cambridge, where the average is 10*4; and an undoubted female Gorilla with 14 m m . ) ; and the mounted skeleton measures 1 The label runs:-" Troglodytes gorilla (Cuv.). Junger weiblicher Gorilla, von einem Urunga Neger, 1885, in der Kolonie Gaboon erlegt." |
