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Show 1882.J MR. W. A. FORBES ON THE GREAT ANTEATER. 291 slightly-elevated ridge, which in one specimen is divided into three or four slightly-marked papillte. 2. Brain.-The late Prof. Gervais has given, in his memoir on the brain ot Edentata, figures of the superior, inferior, and lateral aspects of the brain oi Myrmecophaga jubata, as well as of the cranial casts of that and the other species of Anteater1. Pouchet, in his ' Memoires,' also gives figures of the cranial casts of Myrmecophaya, and, in the article in the «Journal de l'Anatomie' above cited, representations of the brain itself of Tamandua and Cycloturus, that organ having been previously figured in the latter species by Tiede-mann 2. As I find Gervais's figures of the brain in some respects unsatisfactory, I have taken this opportunity of giving representations of the brains extracted from m y two specimens, including one showing the disposition of the deeper parts (figs. 2, 3, 4, pp. 292, 293). The olfactory lobes are very large, projecting forwards for *7 inch in front of the cerebral hemispheres : in the lateral view of the brain they occupy, at least anteriorly, almost the lower half of the parts there exposed. They are continuous basally with the well-developed " hippocampal lobe," in front of which appears a large oval swelling of grey matter, on the middle root of the olfactory lobe, of an antero-posterior extent of more than half an inch. Towards their base, the olfactory tracts are curiously marked by slight transverse impressions (fig. 3) giving them a striated appearance, which may also be observed in the corresponding regions in the brains of Tamandua and Orycteropus. The cerebral hemispheres are but little arched superiorly3; but the vermis cerebelli is very prominent, rising above the general level of the hemispheres (fig. 2). Viewed from above, the hemispheres appear somewhat truncated posteriorly, though they here completely conceal the corpora quadrigemina, abutting on the cerebellum (fig. 2). Attaining their greatest breadth anterior to this, a little in front of the level of the posterior end of the median fissure (1*95 inch long), they taper somewhat rapidly anteriorly. The cerebellum is well convoluted, with its lateral extent (1*5 inch) greater than its antero-posterior (1*15). The vermis is much narrower than the lateral lobes ; it is prominent, and in one specimen (the larger) considerably twisted on itself. The flocculi are distinct. The nates are much larger than the testes : the latter are very narrow from before backwards as compared with their combined transverse extent (*075 : -6 inch), and are not distinctly separated from each other. The nates are larger, more prominent, and distinctly paired, being separated by a well-marked constriction; they are somewhat triangular in shape, with their longer axis transverse. 1 Nouv. Arcb. v. pl. i. figs. 3, 3a, 3b, pl. ii. figs. 1-3. 2 Icones cerebri Simiarum, pl. v. fig. 8. 3 Gervais's figure, I. c. fig. 3 a, makes their outline much too convex antero-posteriorly. |
