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Show 14 THE DESCENT OF MAN. PART I. differs from woman in size, bodily strength, hairyness, &c., as well as in mind, in the same manner as do the two sexes of many mammals. It is, in short, scarcely possible to exaggerate the close correspondence in general structure, in the minute structure of the tissues, in chemical composition and in constitution, between man and the higher animals, especially the anthropomor-phous apes. · Embryonic Development.-Man is developed from an ovule, about the 125t.h of an inch in diameter, which differs in no respect from the ovules of other animals. The embryo itself at a very early period can hArdly be distinguished from that of other members of the vertebrate kingdom. At this period the arteries run in archlike branches, as if to carry the blood to branchire which are not present in the higher vertebrata, though the slits on the sides of the neck still remain (f, g, fig.l ), marking their former position. At a somewhat later period, when the extremities are developed, "the feet of " lizards and mammals," as the illustrious Von Baer remarks, " the wings and feet of birds, no less than the ': hands and feet of man, all arise from the same funda" mental form." It is, says Prof. Huxley,10 "quite in " the later stages of development that the young human " being presents marked differences from the young "ape, while the latter departs as much from the dog " in its developments, as the man does. Startling as " this last assertion may appear to be, it is demonstrably "true." As some of my readers may never have seen a drawing of an embryo, I have given one of man and another of a dog, at about the same early stage of development, 10 'l\fn.n's Place in Nn.turc,' 18G3, p. G7. CIIAP. I. EMBRYONIC DEVELOPMENT. Fig. I. Upper figure human embryo, from Ecker. Lower figure that of 11 dog, from Bischoff. a. :Fore-brain, cerebral hemispheres, &c. g. Second visceral arch, 15 b. lliid-brdin, corpora quadrigemina. H. Vertebral columns and muscles in c. Hind-brain, cerebellum, medulla ob-longata. d. Eye. process of development. i. Anterior } , lC. Posterior extrcmittes. e. Ear. f. First 'visceral arch. L. Tail or os coccyx. |