“The Descent of Man” 147 
in geology which Darwin maintained throughout his life and his 
complete knowledge of palaeontology enabled him to grasp the funda- 
mental importance of the palaeontological record more clearly than 
anthropologists and zoologists usually do. 
There has been much debate in subsequent decades whether 
Darwin himself maintained that man was descended from the ape, 
and many writers have sought to deny it. But the lines I have 
quoted verbatim from the conclusion of the sixth chapter of the 
Descent of Man (1871) leave no doubt that he was as firmly con- 
vinced of it as was his great precursor Jean Lamarck in 1809. 
Moreover, Darwin adds, with particular explicitness, in the “general 
summary and conclusion” (chap. XxXI.) of that standard work?: 
“By considering the embryological structure of man—the homo- 
logies which he presents with the lower animals,—the rudiments 
which he retains,—and the reversions to which he is liable, we can 
partly recall in imagination the former condition of our early pro- 
genitors; and can approximately place them in their proper place in 
the zoological series. We thus learn that man is descended from a 
hairy, tailed quadruped, probably arboreal in its habits, and an 
inhabitant of the Old World. This creature, if its whole structure 
had been examined by a naturalist, would have been classed amongst 
the Quadrumana, as surely as the still more ancient progenitor of the 
Old and New World monkeys.” 
These clear and definite lines leave no doubt that Darwin—so 
critical and cautious in regard to important conclusions—was quite 
as firmly convinced of the descent of man from the apes (the Catar- 
rhinae, in particular) as Lamarck was in 1809 and Huxley in 1863. 
It is to be noted particularly that, in these and other observations 
on the subject, Darwin decidedly assumes the monophyletic origin of 
the mammals, including man. It is my own conviction that this is of 
the greatest importance. A number of difficult questions in regard 
to the development of man, in respect of anatomy, physiology, psy- 
chology, and embryology, are easily settled if we do not merely 
extend our progonotaxis to our nearest relatives, the anthropoid 
apes and the tailed monkeys from which these have descended, 
but go further back and find an ancestor in the group of the 
Lemuridae, and still further back to the Marsupials and Monotre- 
mata. The essential identity of all the Mammals in point of ana- 
tomical structure and embryonic development—in spite of their 
astonishing differences in external appearance and habits of life—is 
so palpably significant that modern zoologists are agreed in the 
hypothesis that they have all sprung from a common root, and that 
this root may be sought in the earlier Palaeozoic Amphibia. 
1 Descent of Man, p. 930. 
10—2 
