THE DESCENT OR ORIGIN OF MAN 215 



probably pointed, and capable of movement; and their 

 bodies were provided with a tail, having the proper mus- 

 cles. Their limbs and bodies were also acted on by many 

 muscles which now only occasionally reappear, but are 

 normally present in the Quadrumana. At this or some 

 earlier period, the great artery and nerve of the humerus 

 ran through a supra-con dyloid foramen. The intestine gave 

 forth a much larger diverticulum or ceecum 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 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 once served as 

 a float. The clefts on the neck in the embryo of man show 

 where the branchiae once existed. In the lunar or weekly 

 recurrent periods of some of our functions we apparently 

 still retain traces of our primordial birthplace, a shore 

 washed by the tides. At about this same early period the 

 true kidneys were replaced by the corpora wolffiana. The 

 heart existed as a simple pulsating vessel ; and the chorda 

 dorsalis took the place of a vertebral column. These early 

 ancestors of man, thus seen in the dim recesses of time, must 

 have been as simply, or even still more simply, organized 

 than the lancelet or amphioxus. 



There is one other point deserving a fuller notice. It has 

 long been known that in the vertebrate kingdom one sex 

 bears rudiments of various accessory parts, appertaining to 

 the reproductive system, which properly belong to the oppo- 

 site sex ; and it has now been ascertained that at a very early 

 embryonic period both sexes possess true male and female 

 glands. Hence some remote progenitor of the whole verte- 



