Another difficulty in the way of the Darwinian theory of direct descent is the fact that the best counterparts of human anatomy are not found united in any one species of ape or monkey, but are scattered throughout a large number of species. “Returning to the old discussion,” says Thomas Dwight, “as to which ape can boast of the closest resemblance to man, Kohlbrugge brings before us Aeby’s forgotten book on the skull of man and apes. His measurements show that the form nearest to man among apes is the gibbon, or long-armed ape, but that the South American monkey _Crysothrix_ is nearer still. Aeby recognized what modern anatomists have forgotten or wilfully ignored: that any system of descent is inadequate which does not recognize that the type of man is not in any one organ, but in all the physical and psychological features. He declared that while we are far from having this universal knowledge, we have learned enough about the various parts of the body to make it impossible for us to sketch any plan of descent. ‘It almost seems as if every part had its own line of descent, different from that of others.’ ... Kohlbrugge now introduces Haacke, who denies any relationship between man and apes, the latter being instances of one-sided development. He even dares to declare anyone who speaks of an intermediate form between man and apes to be ignorant of the laws of development governing the race history of mammals. He believes man came from some lemuroid form, which may have descended from the insectivora.” (“Thoughts of a Catholic Anatomist,” pp. 188-190.) All known types, then, of apes and monkeys are too specialized to have been in the direct line of human descent. Man, as Kohlbrugge ironically remarks, appears to have come from an ancestor much more like himself than any species of ape we know of. Moreover, no species of apes or monkeys monopolizes the honors of closest resemblance to man. In many points, the South American monkeys, though more primitive than the anthropoid apes, are more similar to man than the latter. § 2. Embryological Resemblances