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Show 1885.] DR. ST. G. MIVART ON THE ARCTOIDEA. 353 The female generative organs and placentation have been described by Dr. M.. Watson1. According to this observer, the placenta forms a complete ring, but at the widest part, opposite the back of the foetus, he found a spot similar to that figured by Daubenton2 in the placenta of Maries domestica, and described by Bischoff in that of Lutra vulgaris3, Mustela foina, and Mustela martes4, where the substance of the placenta was very defective. Procyon agrees with Canis and differs from Felis, " in the absence of a continuous layer of decidua serotina from the uterine surface of the detached placenta." It differs from all Carnivora yet known in having the foetus provided with an extra article, or epitrichium ; a structure found in Cholozpus hoffmanni, Bradypus, Myrmecophaga, Dicotyles, Sus, and Equus. It also agrees with Cholozpus hoffmanni in the possession5 of certain peculiar placental vessels not hitherto found in any other animals. Dr. Watson finally records that it " differs from every other Carnivore, the foetus of which has been hitherto examined, in the non-possession of an umbilical vesicle." The brain6 shows a parietal gyrus which does not bifurcate posteriorly as it does in the Cynoidea. The Sylvian gyrus has its anterior limb much smaller than its posterior limb. The parietal gyrus is large, expanding anteriorly, becoming considerably contorted, and sometimes communicating, by a bridge of convolution, with the sagittal gyrus. The sagittal gyrus is very large, and becomes complicated anteriorly. In P. cancrivorus there are two or three bridging convolutions on each side, between the parietal and the sagittal gyri. The hippocampal gyrus continues upwards into the sagittal gyrus behind the cranial sulcus7, the calloso-marginal sulcus not being continued forwards into the latter. The crucial sulcus is very large and distinct, and sends forwards and inwards a small precrucial sulcus, thus defining, with its fellow of the opposite side, a conspicuous diamond-shaped patch of brain-substance, which has been called the " Ursine lozenge." The genus Nasua comprises two species, N. narica8 and N. 1 See Proc. Royal Soc. 1881, vol. xxxii. p. 272. 2 Buffon, Hist. Nat. vol. vii. pi. xx. 3 Sitzungsb. Akad. Wissensch. Miinchen, 11 Miirz, 1865. * Ibid. 19 Mai, 1865. 5 See Prof. Turner's paper, Trans. Roy. Soc. Edin. vol. xxvu. p. 79. 6 See a paper entitled " Notes on the Cerebral Convolutions of the Carnivora," in the Journal of the Linnean Society, vol. xix. (1885), p. 10. 7 As in the Felidce. 8 Nasua, Storr, Prod. Meth. M a m m . p. 35 (1780). Caoti, Lacepede, Mem. de l'Hist. Nat. iii. p. 492 (1801). Viverra narica, Linn. Syst. Nat. i. p. 64 (1766). Coati mundi, Brisson, Regne Anim. 1756, p. 262. Coati brun, Buffon, viii. 1760, p. 358, pi. 48. Nasua narica, Allen, Bull. U. S. Geol. Survey, v. p. 162 Nasua leucorhynchus, Tschudi, Fauna Peru, p. 100 (1846); Frantzms, Arch. f Naturg xxxi. i. p. 29*2 ; Hensel, Abb. Akad. Berlin, 1872, p. 65. N fusca. Tomes, P. Z. S. 1861, p. 280. N solitaria, var. mexicana, Weinland, Zool. Garten, 1860, p. 191, pi. 1. JV"! naria, Alston, Biologia Centrali-Americana, Mammals, 1879, p. 74. |