THE KINSHIP OF LIFE. 41 
plained; special creation can not account for it. Going 
still further back in the history of the development of 
the mammals, the record shows that both these and the 
reptiles must have arisen from fish-like 
forms which breathed water by means 
of gills. To this embryology offers ample support. In 
the embryos of reptiles, birds, and mammals, soon after 
the heart is formed, there appear on the sides of the 
neck openings which in both origin and structure re- 
semble the gill arches of fishes, and through these gills 
the blood flows exactly as it does in the fish. Later the 
gill arches close up, the blood takes other courses, and 
of all the complicated apparatus which persists through- 
out life in the fish there remain only a few obscure 
traces in the adult reptile, bird, or mammal.” 
This fact must show that the higher mammals have 
had a water-breathing, fish-like ancestry. Only the force 
of heredity can explain the existence and retention of 
these structures. On any other supposition an explana- 
tion is inconceivable. 
Dr. Kingsley further says: “These examples are but 
a tithe of the evidence; thousands of pages might be 
written detailing similar facts not only in connection 
with the embryology of the vertebrates but of all groups 
of animals and plants. Every case would lead us to the 
same conclusions, but except for the special student of 
biology they would have but little interest. Each in- 
stance would be inexplicable except upon an evolu- 
tionary basis, but, if one adopt the hypothesis that the 
history of the individual is an epitome of that of the 
race, all is at once as clear as day. Special creation is 
utterly inadequate to explain embryological problems ; 
evolution leaves no room for doubt or question.” 
The difficulties and objections to the theory of de- 
scent will be found in the Origin of Species, stated by 
Gill slits in man. 
