After our female ancestors had acquired the new character, nudity, they must have transmitted it to their own sex, and by continually selecting their mates from among the least hairy, in process of time males too would become divested of their animal covering. Whether or not our semi-human ancestors were subjected to the scorching heat of the torrid zone, nudity must have been better suited to their improved condition, not wholly, however, because of its greater beauty and comfort, but because it was a condition better suited to cleanliness; and, as the hairy coat had become a useless appendage, or was not necessary to their changed conditions, it disappeared from the bodies of females, while doubtless for ages it was retained upon the bodies of males. That hairiness denotes a low stage of development, Mr. Darwin incautiously admits, yet in dealing with this subject he is not disposed to carry his admission to its legitimate conclusion by treating its appearance on the body of man as a test in determining the comparative development of the female and male organisms. Idiots, who, by the way, are more numerous among males than among females, are frequently covered with hair, and by the acquirement of other characters more often revert to lower animal types. Mr. Darwin assures us that around sores of long standing stiff hairs are liable to appear, thus showing that hair on the body is indicative of undeveloped tissues and low constitutional conditions. The same writer, however, does not neglect to inform us that the loss of man’s hairy covering was rather an injury to him than otherwise; but whether or not the diminution in the quality of prehension in his toes, the loss of his canines, and the disappearance of his tail have likewise proved detrimental to him, Mr. Darwin fails to state. The fact that throughout the vertebrate kingdom males possess rudiments of the various parts appertaining to the reproductive system which properly belong to females, is regarded as evidence that some remote progenitor of this kingdom must have been hermaphrodite, or androgynous, especially as it has been ascertained that at a very early embryonic period both sexes possess true male and female glands. As high in the scale of life as the mammalian class, males are said to possess rudiments of a uterus, while at the same time mammary glands are plainly manifest; which fact would seem to show that in the high state of development indicated by this great class, male organs have not through the processes of differentiation become specialized for the performance of their legitimate functions. In reference to the subject of atavism Mr. Darwin cites as a case of reversion to a former type, an instance in which a man was the possessor of two pairs of mammæ.