26 THE DESCENT OF MAN 



as if to carry the blood to branchiae which are not present in 

 the higher vertebrata, though the slits on the sides of the 

 neck still remain (/, g, Fig. 1), marking their former posi- 

 tion. At a somewhat later period, when the extremities are 

 developed, "the feet of lizards and mammals," as the illus- 

 trious Von Baer remarks, "the wings and feet of birds, no 

 less than the hands and feet of man, all arise from the same 

 fundamental form." It is, says Prof. Huxley," "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 de- 

 velopments 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, carefully 

 copied from two works of undoubted accuracy." 



After the foregoing statements made by such high au- 

 thorities, it would be superfluous on my part to give a num- 

 ber of borrowed details, showing that the embryo of man 

 closely resembles that of other mammals. It may, however, 

 be added, that the human embryo likewise resembles certain 

 low forms when adult in various points, of structure. For 

 instance, the heart at first exists as a simple pulsating ves- 

 sel; the excreta are voided through a cloacal passage; and 

 the OS coccyx projects like a true tail, "extending consider- 

 ably beyond the rudimentary legs." " In the embryos of all 

 air-breathing vertebrates, certain glands, called the corpora 



" "Man's Place in Nature," 1863, p. &l. 



" The human embryo (upper fig.) is from Ecker, "Icones Phys.," 1851- 

 1859, tab. XXX. lig. 2. This embryo was ten lines in length, so that the 

 drawing is much magnified. The embryo of the dog is from Bischoff, "But- 

 wicklungsgeschichte des Hunde-Eies," 1845, tab. xi. fig. 42 B. This drawing 

 is five times magnified, the embryo being twenty-five days old. The internal 

 viscera have been omitted, and the uterine appendages in both drawmgs re- 

 moved. I was directed to these figures by Prof. Huxley, from whose work, 

 "Man's Place in Nature," the idea of giving them was taken. Hackel has also 

 g^ven analogous drawings in his "Schopfungageschichte. " 



'• Proi Wyman in "Proc. of American Acad, of Sciences," vol. Iv., 1860, 

 pi. It. 



