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 morpho- 
logy 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 bran- 
chiae once existed. At about this period the true kid- 
neys were replaced by the corpora wolffiana. The heart 
ex isted 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 
°t time, must have been as lowly organised as the lance- 
Ict or amphioxus, or even still more lowly organised. 
There is one other point deserving a fuller notice, 
bt has long been known that in the vertebrate king- 
i o o 
c *om one sex hears rudiments of various accessory 
Parts, appertaining to the reproductive system, which 
Properly belong to the opposite sex; and it lias now 
been ascertained that at a very early embryonic period 
both sexes possess true male and female glands. Hence 
S0) ne extremely remote progenitor of the whole verte- 
brate kingdom appears to have been hermaphrodite or 
androgynous . 23 Hut here we encounter a singular 
difficulty. In the mammalian class the males possess 
21 This is the conclusion of one of the Highest authorities in com- 
parative auatomy, namely, Prof. Gegenbaur : ‘Grnndziige dor vergleich. 
y 1(l h 1871), g. 876. The result lias been arrived at chiefly from the 
s udy of the Amphibia ; but it appears from the researches of Waldeyer 
h ls quoted in Humphry’s ‘ Journal of Auat. and Phys.’ 1869, p. 161), 
,, t the sexual organs of even “ the higher vertebrata are, in tlieir early 
c °ndition, hermaphrodite.” Similar views have long been hold by 
s °tnc authors, though until recently not well based. 
