i6o 



The Deccent of Man. 



Paiit 1 



confirmed by Prof. Kupffer. M. Kovalevsky writes to me from 

 Naples, that he has now carried these observations yet further ; 

 and should his results be well established, the whole will form a 

 discovery of the very greatest value. Thus, if we may rely on 

 embryology, ever the safest guide in classification, it seems that 

 we have at last gained a clue to the source whence the Yertebrata 

 were derived. 25 We should then be justified in believing 

 that at an extremely remote period a group of animals existed, 

 resembling in many respects the larvae of our present Ascidians, 

 which diverged into two great branches— the one retrograding in 

 development and producing the present class of Ascidians, the 

 other rising to the crown and summit of the animal kingdom by 

 giving birth to the Vertebrata. 



We have thus far endeavoured rudely to trace the genealogy 

 of the Vertebrata by the aid of their mutual affinities. We will 

 now look to man as he exists ; and we shall, I think, be able 

 partially to restore the structure of our early progenitors, during 

 successive periods, but not in due order of time. This can be 

 effected by means of the rudiments which man still retains, by 

 the characters which occasionally make their appearance in him 

 through reversion, and by the aid of the principles of morphology 

 and embryology. The various facts, to which I shall here allude, 

 have been given in the previous chaj)ters. 



The early progenitors of man must have been once covered 

 with hair, both sexes having beards ; their ears were probably 

 pointed, and capable of movement ; and their bodies were pro- 

 vided with a tail, having the proper muscles. Their limbs and 

 bodies were also acted on by many muscles which now only 

 occasionally reappear, but are normally present in the Quaclru- 

 mana. At this or some earlier period, the great artery and nerve 

 of the humerus ran through a supra-conclyloid foramen. The 

 intestine gave forth a much larger diverticulum or caecum than 

 that now existing. The foot was then prehensile, judging from 

 the condition of the great toe in the foetus ; and our progenitors, 

 no doubt, were arboreal in their habits, and frequented some 

 warm, forest-clad land. The males had great canine teeth, which 



25 But I am bound to add that 

 some competent judges dispute this 

 conclusion ; tor instance, M. Giard, 

 in a series of papers in the 'Archives 

 de Zoologie Experimentale,' for 1872. 

 Nevertheless, this naturalist re- 

 marks, p. 281, " L'o^ganisation de la 

 " larve ascidienne en dehors de 

 ** toute hypothese et de toutethebrie, 

 " aous rnontre comncent la nature 



" peut produire la disposition fonda- 

 '• mentale du type vertebre (l'ex- 

 " istence d'une corde dorsale) chez 

 " nn iuvertebre par la seule con- 

 " ditiou vitale de l'adaptation, 

 " et cette simple possibility du 

 ' ; passage supprimc l'abime entre 

 " les deux sous-regnes, encore bien 

 ' ; qu'en igDore par oil le passage 

 i: s : est fait en realiti " 



