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THE POPULAR SCIENCE MONTHLY. 



highly developed, and the other atrophying, according to sex. 

 This fact, of course, points back conclusively to primitive ances- 

 tors of fishes, reptiles, birds, and mammals, which were her- 

 maphrodite. The argument for design is utterly put out of court 

 by the awkwardness of the whole plan, and the disease and suf- 

 fering caused in mammalian females by the ovaries having no 



Fig. 2.— Pineal Eye in Varanus giganteus. A, nerve divided into three branches ; B, blood-vessel 

 branching and going round the eye ; C, mass of pigment. 



original connection with the uterus and by the survival of useless 

 rudimentary organs. As a blind effort of Nature in the process 

 of converting a hermaphrodite worm into a warm blooded mam- 

 mal, the process has its wonderful and admirable side. The third 

 set of kidneys are, of course, the permanent ones. 



Prof. Cope, in his "Origin of the Fittest," draws attention 

 to what he names the "law of acceleration and retardation." 

 This law, though it may indirectly lead to the " survival of the 

 fittest," is equally likely, through its blind action, to lead to the 

 extinction of an animal which had once been the " fittest " in its 



