98 A. Aw. W. HUBRECHT. 
marked. Where the mucosa faces the flattened surface at one 
of the poles of the chorion above alluded to, the reticulation is 
also deficient. 
Galeopithecus. Figs. 6—11, 24—29, 57, 58. 
Concerning the ontogeny and the placentation of Galeo- 
pithecus, I could find no data in the mammalian literature 
but a few lines in an article of Gervais! on the cerebral 
conformation of the Mammalia (1. c., p. 425). He does no 
more than mention the fact that he examined a foetus of 
Galeopithecus which was shown to possess a discoid placenta. 
Without entering into any further details, he figures (I. c., 
pl. 22) the said foetus with outspread patagium and severed 
umbilical cord (fig. 1), and the same folded together in its 
intra-uterine position and attached by a thick and short 
umbilical cord to a disk-shaped placenta on which a number of 
radiating blood-vessels are indicated. 
Gervais’s figure corresponds in a general way with fig. 29 of 
this paper, only it is much smaller, and was probably not 
figured natural size. In our fig. 29 the circular placentary 
area is seen to lie as nearly as possible in the level of the 
uterine surface, and not to form such a marked button-shaped 
prominence as, for example, the placenta of Tarsius figured 
close to it (fig. 20) does to such a considerable extent. 
Though both discoid, these two placentas are, no doubt, 
also in other respects profoundly divergent from each other. 
Although I have as yet only a provisional acquaintance with 
the chief stages of the placentation of Galeopithecus, I can 
more especially call the attention to the peculiar aspect of the 
placenta in figs. 24, 25, and 27. 
It is already a discoid formation, but in these younger stages 
it is less compact and less intimately soldered with the uterine 
walls; the placental vessels, on the contrary, being mutually 
interwoven in an intricate manner, and being applied as a 
1 “Mémoire sur les formes cérébrales propres a différents groupes de 
mammiféres,” ‘ Journal de Zoologie,’ vol. i, 1872. 
