MAN'S GENEALOGY Darwin's Views.—Although there is a complete agreement among professional students that man is a member of that order of mammals to which Linnaeus gave the name "Primates" and that his lineage when traced backwards, will be found to branch off from the primate tree, there is a sharp difference of opinion as to the exact point in the tree, and the approximate date in geo logical time, at which the human branch separates from those other main branches which represent the lineage of anthropoid apes and of monkeys. It is clear from statements made in the Descent of Man, that Darwin regarded the gorilla and chimpanzee as more nearly akin to man than other living primates and, on the evidence available in 1871, thought it probable that man and the African anthropoids were co-descendants of a common anthropoid which had its habitat in Africa (fig. r). He regarded the catarhine type of monkey—the type exemplified by the monkeys of the Old World—as representatives of a still older ancestral form. Darwin traced the common anthropoid stock, which gave birth not only to the ancestral lines of man, the gorilla and chimpanzee, but also to those of the orang and gibbon, back to a common catarhine type. This catarhine type, he presumed, was the offspring of a still older common simian or monkey-like type, one which existed in the Eocene period of the earth's his tory and gave origin not only to the catarhine monkeys of the Old World but also to the platyrhine monkeys of the New World. Thus man's history, as Darwin saw it, did not begin until after the ancestral type of anthropoid had been evolved ; the appearance of an anthropoid type from a common catarhine ancestor and this from a common simian stock, represent prehuman stages in the evolution of the higher primates. It is noteworthy that Dar win's mind remained open as to the exact point at which the human stock branched off from the general primate tree (fig. Ia).
pedigree is still worthy of study (fig. 2). Haeckel perceived that the small form of anthropoid ape, the gibbon, was more primitive and earlier in point of evolution than the three living great anthro poid apes (orang, chimpanzee and gorilla) and supposed that in the evolution of the great anthropoids from the ancestral catarhine type there was interposed a small anthropoid stage to which he gave the name Lipocerca (Xoreiy, to lack, Kiptcos, tail). This small anthropoid stock (Lipo cerca) gave origin, he supposed, to gibbons and to the ancestral stock of the great anthropoids— for which Haeckel proposed the name Lipotyla (Xtreiv, to lack, ran, c u s h i o n)—anthropoids which, unlike the gibbons, were destitute of ischial callosities or natural cushions on which gib bons and Old World monkeys seat themselves. This cushionless anthropoid stock (Lipotyla) he regarded as ancestral to the vari ous races of mankind. From the Lipotyla, which gave origin to man, there also branched off, at an early stage, the ancestry of the orang and, at a later, the com mon ancestry of the chimpanzee and gorilla. Thus Haeckel regarded the gorilla and chimpanzee as more nearly related to man than other living anthropoids. It is also remarkable that he placed the extinct Miocene form of anthropoid ape, known as Dryopithecus, on the line which led up to the gorilla and chimpanzee on the one hand and to human races on the other. Thus it will be seen that in Haeckel's opinion man was the descendant of an anthropoid ape.
Later, he introduced considerable modifications into this fam ily tree. In the third edition of his Evolution of Man (English translation, 1879) he interpolated into man's ascent from an an thropoid to a human state an intermediate stage represented by ape-like men—beings who were manlike in form and in gait but lacked man's power of speech. To such hypothetical beings he gave the name Pithecanthropi.