14 THE DESCENT OF MAN. [Part I. 



respondence in general structure, in the minute structure 

 of the tissues, in chemical composition, and in constitution, 

 between man and the higher animals, especially the an- 

 thropomorphous apes. 



■ 



Embryonic Development. — Man is developed from an 

 ovule, about the 125th 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 verte- 

 brate kingdom. At this period the arteries run in arch- 

 like branches, 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 position. At a somewhat later period, when 

 the extremities are developed, "the feet of lizards and 

 mammals," as the illustrious Yon 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, 10 " quite in the latter stages of de- 

 velopment 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 de- 

 monstrably true." 



As some of my readers may never have seen a draw- 

 ing 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. 11 



10 ' Man's Place in Nature,' 1863, p. 67. 



11 The human embryo (upper fig.) is from Ecker, 'Icones Phys.,' 

 1851-1859, tab. xxx. fig. 2. This embryo was ten lines in length, so that 

 the drawing is much magnified. The embryo of the dog is from Bi- 

 Bchoff, ' Entwicklungsgcschichte des Hunde-Eies,' 1845, tab. xi. fig. 42 b. 

 This drawing is five times magnified, the embryo being 25 days old. The 



