424 THE EVOLUTION OF MAN. 



perfectly. As we have already seen that the original 

 rudiment of the sexual organs is really hermaphroditic in 

 all Vertebrates, and that the separation of the sexes is only 

 due to a one-sided development of this hermaphroditic 

 rudiment, these remarkable cases offer no theoretic diffi- 

 culties. They very seldom, however, occur in Man and the 

 higher Vertebrates. On the other hand, we find original 

 hennaphroditism constant in some lower Vertebrates, as in 

 some Fishes of the Perch kind (Serrartus), and in some 

 Amphibia (Bombinator and in Toads). In these cases, the 

 male has usually a rudimentary ovary at the upper ex- 

 tremity of the testis ; on the other hand, the female has 

 sometimes a rudimentary testis, without function. This 

 also occurs occasionally in Carp and some other Fishes. 

 We have already seen how the original hennaphroditism 

 is maintained in the excretory ducts, in Amphibia. 



In the germ-history of the human urinary and sexual 

 organs, the outlines of the history of human descent have 

 been faithfully maintained up to the present time. We can 

 trace their development in the human embryo step by step, 

 in the same gradations as are exhibited, one after another, 

 in the comparison of the urogenitals in Acrania, Cyclostomi, 

 Fishes, Amphibians, and then further, in the series of 

 Mammals, in Cloaca! Animals (Monotremes), Pouched 

 A nimals (Marsupialia), and the various Placental Animals. 

 (Cf. Table XLIII.) All the structural peculiarities of the 

 urogenitals, distinguishing Mammals from other Verte- 

 brates, are also present in Man ; and in all special charac- 

 teristics the latter resembles the Apes, and especially the 

 Anthropoid Apes. As evidence that the special peculiarities 

 of Mammals have been transmitted to Man, I will finally 



