HOMOLOGJCAL STRUCTURES. 



the birth and nurturing of the young. Monkeys are bom 

 in almost as helpless a condition as our own infants; and in 

 certain genera the young differ fully as much in appearance 

 from the adults, as do our children from their full-grown 

 parents.* It has been urged by some writers, as an import- 

 ant distinction, that with man the young arrive at maturity 

 at a much later age than with any other animal: but if we 

 look to the races of mankind which inhabit tropical coun- 

 tries the difference is not great, for the orang is believed 

 not to be adult till the age of from ten to fifteen years, f 

 Man differs from woman in size, bodily strength, hairiness, 

 etc., as well as in mind, in the same manner as do the two 

 sexes of many mammals. So that the 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 anthropomorphous apes, ^ 

 is extremly close. 



Embryonic Development. Man is developed from an 

 o^'ule, 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 distin- 

 guished from that of other members of the vertebrate king- 

 dom. 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 posi- 

 tion. 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 fundamental form," It is, says Prof. Huxley,]; 



cepbalo. Illustrissimus Cuvier etiam narrat multa de liac re, qua 

 ut opinor, nihil turpius potest indicari inter omnia hominibus et 

 Quadrumanis communia. Narrat enijn Cynocephalum quendam in 

 furorem incidere aspectu feminarum aliquarum, sed nequaquam ac- 

 cendi tanto furore ab omnibus. Semper eligebat juniores, et dignos- 

 cebat in turba, et advocabat voce gestuque. 



*Tbis remark is made with respect to Cynocephalus and the 

 anthropomorphous apes by Geoffroy Saint-Hilaire and F. Cuvier, 

 * Hist, Nat. des Manimiferes," torn, i, 1824. 



t Huxley, " Man's Place in Nature." 1863, p. 34. 



X Ibid., p. 67. 



