We have already shown that the fœtus of man and of the anthropoid monkeys resemble each other much more than the adult forms, and that the young of these apes also bear a greater likeness to man than do the adults. The great development of the skull as compared with the face is characteristic of young monkeys and of man young or old. The jaws continue to develop in the anthropoids, while in man there occurs in this respect a certain arrest of development. The hairs, so small in man, also show a similar arrest. Generally they remain during the whole life in a state of incomplete development. It is especially on the back of man that this feeble development of hairs occurs. As this part of the body in monkeys, on the contrary, is much more hairy than the under surface, it has been held to constitute an essential difference between man and monkeys. But embryological study enables us to settle this apparent contradiction. The fœtus of the gorilla examined by M. Deniker possessed an almost entirely smooth back. “The fœtus had true hairs only on the head, the anterior surface, and around the lips and the genital organs, and the eyelashes and eyebrows. The remainder of the body was smooth or covered with down not exceeding a millimetre in length.”[63] The skin of the under surface, smooth around the navel, was covered with small hairs more thickly than on the back. The abundance of hairs on the posterior aspect of the body of monkeys is a later acquisition, which develops but tardily during fœtal life. As regards the distribution of these hairs man resembles much more the embryos of monkeys than adult monkeys. This fact, instead of shaking the theory of relationship between man and apes, gives us strong evidence as to the mode of his descent. Putting the known facts together, we may infer that man is a case of the arrested development of some simian of ancient days, as it were, a simian monster from the zoological point of view, although not from the æsthetic. Man may be regarded as a prodigy sprung from an ape, born with a larger brain and an intelligence more highly developed than occurred in his parents. Such a view is in accordance with known facts. It must be admitted that certain kinds of organisms, instead of evolving at a very slow pace, spring up suddenly, and that in such a case nature proceeds with a considerable stride. Darwin foresaw this possibility, but it has been made plain to us by the remarkable researches of the botanist Hugo de Vries.[64]