Chap. VI. AFFINITIES AND GENEALOGY. 207 



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 mem- 

 brane. 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. At about this 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 predecessors of man, thus seen in the dim 

 recesses of time, must have been as lowly organised 

 as the lancelet or amphioxus, or even still more lowly 

 organised. 



There is one other point deserving a fuller notice. 

 It has long been known that in the vertebrate king- 

 dom one sex bears rudiments of various accessory 

 parts, appertaining to the reproductive system, which 

 properly belong to the opposite sex; and it has now 

 been ascertained that at a very early embryonic period 

 both sexes possess true male and female glands. Hence 

 some extremely remote progenitor of the whole verte- 

 brate kingdom appears to have been hermaphrodite or 

 androgynous. 23 But here we encounter a singular 



23 This is the conclusion of one of the highest authorities in com- 

 parative anatomy, namely, Prof. Gegenbaur : ' Grundziige der vergleich. 

 Anat." 1870, s. 876. The result has been arrived at chiefly from the 

 study of the Amphibia ; but it appears from the researches of Waldeyer 

 (as quoted in Humphry's 'Journal of Anat. and Phys.' 1869, p. 161), 

 that the sexual organs of even " the higher vertebrata are, in their early 

 " condition, hermaphrodite." Similar views have long been held by 

 some authors, though until recently not well based. 



