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 : 4 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. 
