196 THE HISTORY OF CREATION. 



different generative substances, the male sperm and the 

 female egg, are either produced by one and the same indi- 

 vidual hermaphrodite (Hermaphroditismus), or by two 

 different individuals (sexual separation, Gonochorismus) 

 (Gen. Morph. ii. 58, 59). 



The simpler and more ancient form of sexual propagation 

 is through double-sexed individuals (Hermaphroditismus). 

 It occurs in the great majority of plants, but only in a 

 minority of animals, for example, in the garden snails, 

 leeches, earth-worms, and many other worms. Every single 

 individual among hermaphrodites produces within itself 

 materials of both sexes — eggs and sperm. In most of the 

 higher plants every blossom contains both the male organ 

 (stamens and anther) and the female organs (style and 

 germ). Every garden snail produces in one part of its 

 sexual gland eggs, and in another part sperm. Many her- 

 maphrodites can fructify themselves ; in others, however, 

 copulation and reciprocal fructification of both hermaphro- 

 dites is necessary for causing the development of the eo-o-s. 

 This latter case is evidently a transition to sexual separa- 

 tion. 



Sexual separation (Gonochorismus,) which characterizes 

 the more complicated of the two kinds of sexual reproduc- 

 tion, has evidently been developed from the condition of 

 hermaphroditism at a late period of the organic history of 

 the world. It is at present the universal method of propa- 

 gation of the higher animals, and occurs, on the other hand, 

 only in the minority of plants (for example, in many aquatic 

 plants, e.g. Hydrocharis, Vallisneria ; and in trees, e.g. 

 Willows, Poplars). Every organic individual, as a non- 

 hermaphrodite (Gonochoristus), produces within itself only 



