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Show 1900.] ON THE BRAIN OF THE SIAMANG. 187 PLATE XVI. Xenelaphis ellipsifer, p. 184. § nat. size. Upper and side views of head and neck and of middle of body. PLATE XVII. Fig. 1. Amblycephalus nuchalis, p. 185. Upper and side views of head and neck. 1 a. Lower view of head, xl|. 1 b. Dorsal scales, X 1>J. 2. Ekacophorus shelfordi, p. 185. 3. Ixalus peter si, p. 185. 4. Calophrynus heterochirus, p. 186. 2. On the Brain of a Siamang (Hylobates syndactylus). By F R A N K E. B E D D A R D , M.A., F.R.S., Prosector and Vice- Secretary to the Society. [Received January 30, 1900.] The death of the Society's specimen of this rare Anthropoid Ape1 has enabled me to study an exceedingly well-prepared brain. In bringing before the Society some notes upon the cerebral characters of this Ape, I am not breaking new ground. More than thirty years ago Sir William Flower 2 described the general outline of the brain of this Ape from a cast of the cranial cavity. The account was accompanied by several woodcuts in the text, illustrating one remarkable feature in the brain, which was described in the following words : " The most striking peculiarity of the brain is the backward projection of the cerebellum beyond the level of the cerebral hemispheres, a circumstance, as far as I am aware. unknown in any of the Apes either of the Old or New World.'" This feature is not shown distinctly, but there are indications of it, in Prof. Kohlbriigge's figure3 of the brain, of the Siamang. It appears from the latter drawing that the cerebellum would be visible on an inspection of the brain from above, though Kohlbriigge remarks that the contrary is the case-without, however, referring to Flower's observations on the matter, having been unable to study his paper. Prof. Kohlbriigge examined eight brains of this Ape. Other writers upon the brain-structure of Hylobates syndactylus are Sandifort 4 and Waldeyer5. Thus not more than ten brains of this species (or genus ?) have been studied. It is not therefore perhaps superfluous to extend this list to eleven brains. i Presented by Mr. Stanley S. Flower, F.Z.S. (See P. Z. S. 1898, p. 588.) * Nat. Hist. Review, 1863, p. 279. 3 " Versuch einer Anatomie des Genus Hylobates^ iu Max Weber's Zool. Ergebn. Bd. ii. p. 186. 4 Verhandelingen over de natuurlijke geschiedenis der Nederlandsche overzeesche bezittingen. Leiden, 1840. * " Das Gibbongehirn," Internat. Beitr. z. wiss. Med. Festschr. Virchow, Bd. i. For this reference I am indebted to Dr. Keith's paper on the Gibbon in 4 Nat. Science,' vol. ix. |
