_Relations between placental forms and Individual Characteristics._—From our entire knowledge of the development of races and of individuals, we may conclude, upon the basis of Huxley’s classification, that an intimate relation exists between the form and character of the placenta and the entire nature of the individual. We find among the non-deciduata, besides the toothless sloths, only the Ungulata, or hoofed quadrupeds, and others developed from them. The arrangement of their teeth, as of their entire digestive apparatus, marks them as belonging to a single family—namely, the herbivora. The zonary placenta characterises a very large family of animals whose peculiarities are distinctly marked, especially with regard to their teeth and digestive apparatus. These belong to the widely diffused and numerous orders of the carnivora. But the most interesting and important group, with reference to our present study, is that characterised by the discoidal placenta; for, since it includes man and the fruit-eating apes, it gives occasion for the comparison between these and other placental animals from the standpoint of dietetics. We observe here at once that the majority of animals having a discoidal placenta subsist chiefly upon fruits and grains, and that the typical representatives of this class, namely, those whose plactental formation is most distinctly discoidal, are also the most exclusively frugivorous. * * * * * Here, as elsewhere in nature, an exact line cannot be drawn. Transitional forms exist everywhere, and to this the placenta is no exception. The most striking accordance, however, exists between the placenta of man and that of the tailless apes—namely, the gorilla, orang, chimpanzee and gibbon. Between other discoidal species, the differentiation, though minute, is clearly marked; but between man and these apes the resemblance is so exact as to stamp them plainly as members of the same family. The completely developed placenta is in the form of a circular disc, about eight inches broad, one inch thick and weighing about two pounds. Its manner of development is identical in the human subject and that of the above-named anthropoid apes. Its exact formation is thus described by Huxley: