134 EVOLUTION OF LIFE. 
exhibited in the embryo of man, is a permanent arrange- 
ment in the Sloth, Monotremata, Birds, and Reptiles. 
Finally, the development of the Skull and Extremities 
illustrates the same principle of the lower forms of lite, 
representing the undeveloped stages of the higher. Has 
the Biologist any theory to offer as an explanation of these 
facts? One may reasonably ask, Why do the flipper of the 
seal, the foot of the turtle, the wing of the bird, the hoof 
of the horse, the claw of the lion, the hand of man, etc., 
develop from a bud? Why are these structures, used for 
such different purposes, constructed on essentially the same 
plan? Is there any explanation of the fact that man and 
the lower animals are undistinguishable in the early stages 
of their existence, and that the transitory phases through 
which man passes in the course of development are more or 
less permanently represented in the lower animals,—that 
is, that man is not absolutely at any time a Reptile or 
Dog, etc., but at a certain period exhibits an organization 
which is undistinguishable from that which later becomes 
a Turtle or Dog, etc.? It seems to us that the theory of 
the higher animals having descended from the lower ex- 
plains perfectly all these facts. We will try to illustrate 
this view by noticing the effects supposed to be produced 
on the posterity of a family by their dispersion. After the 
lapse of ages,.subjected to different conditions of soil, food, 
and climate, the races descending from this family would 
differ so greatly as regards their appearance, language, and 
customs that an Ethnologist might doubt if indeed they 
had come from one stock. If, however, he compared young 
individuals of these races, and found they resembled one 
another, and at an extremely early period of life were even 
undistinguishable, and, further, that sometimes individuals 
appeared that differed greatly from the race from which 
they descended, resembling rather a remote, often more 
barbarous, one; and, finally, that the individuals of a bar- 
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