198 THE DESCENT OF MAN. [Part I. 



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 endeavored rudely to trace the 

 genealogy of the Yertebrata 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 during successive 

 periods, but not in due order of time, the structure of our 

 early progenitors. This can be effected by means of the 

 rudiments which man still retains, by the characters which 

 occasionally make their appearance in him through rever- 

 sion, 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 chapters. The 

 early progenitors of man were no doubt once covered with 

 hair, both sexes having beards ; their ears were jointed 

 and capable of movement ; and their bodies were provided 

 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 Quadrumana. The great artery and nerve of the hu- 

 merus ran through a supra-condyloid foramen. At this or 

 some earlier period, the intestine gave forth a much larger 

 diverticulum or caecum than that now existing. The foot, 

 judging from the condition of the great-toe in the foetus, 

 was then prehensile ; and our progenitors, no doubt, were 

 arboreal in their habits, frequenting some warm, forest-clad 

 land. The males were provided with great canine teeth, 

 which served them as formidable weapons. 



At a much earlier period the uterus was double ; the 

 excreta were voided through a cloaca ; and the eye was 

 protected by a third eyelid or nictitating membrane. At 

 a still earlier period the progenitors of man must have 

 been aquatic in their habits ; for morphology plainly tells 

 us that our lungs consist of a modified swim-bladder, which 



