1885.] DR. ST. G. MIVART ON THE ARCTOIDEA. 353 



The female generative organs and placentation have been described 

 by Dr. M. Watson *. 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 Daubenton ^ in 

 the placenta of Martes domestica, and described by BischofiP 

 in that o( Lutra vulgaris^, Mustela foinn, and Mustela martes^, 

 where the substance of the placenta was very defective. Pro- 

 cyon agrees with Ganis 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 Gholccpus hoffmanni, Bradypus, Myrmecophaga, 

 Dicoiyles, Sus, and Equus. It also agrees with Cholcepus hoffmanni 

 in the possession ° 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 brain ^ 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 com- 

 plicated 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 sulcus^, 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. narica^ and N. 



1 See Proc. Eoyal Soc. 1881, vol. xxxii. p. 272. 



^ Buffon, Hist. Nat. vol. vii. pi. sx. 



' Sitzungsb. Akad. Wissenseh. Munchen, 11 Marz, 1865. 



* Ibid. 19 Mai, 1865. 



' See Prof. Turner's paper, Trans. Roy. Soc. Edin. vol. xxvii. p. 79. 



* See a paper entitled " Notes on the Cerebral Convolutions of the Carnivora," 

 in the Journal of tlie Linnean Society, vol. xix. (1885), p. 10. 



"^ As in the Felidm. 



^ Nasua, Storr, Prod. Meth. Mamm. p. 35 (1780). 



Caoti, Lacepede, Mem. de I'Hist. Nat. iii. p. 492 (1801). 



Viverra narica, Linn. Syst. Nat. i. p. 64 (1766). 



Coati mtmdi, Brisson, Regne Anim. 1756, p. 262. 



Coaii brun, Buffon, viii. 1760, p. 358, pi. 48. 



Nasua narica, Allen, Bull. U. S. Geol. Survey, v. p. 162. 



Nasua leucorhynckus, Tschudi, Fauna Peru, p. 100 (1846) ; Frantzius, Arch. 



f. Naturg. xxxi. i. p. 292 ; Hensel, Abh. Akad. Berlin, 1872, p. 65. 

 N.fusca, Tomes, P. Z. S. 1801, p. 280. 



N. solitaria, var. mexicana, Weinland, Zool. Garten, 1860, p. 191, pi. 1. 

 N. naria, Alston, Biologia Centrali-Americana, Mammals, 1879, p. 74. 



