98 PLAIN FACTS FOR OLD AND YOUNG 



ety, it being well known to nurserymen that some 

 varieties produce the female parts of flowers almost 

 exclusively. 



Curious Modes of Fecundation in Animals.— The 

 modes by which fecundation is effected in animals are 

 still more various and wonderful than in plants. In 

 some of the lower animals, as in most fish and reptiles, 

 both elements are discharged from the bodies of the 

 parents before coming in contact, there being no con- 

 tact of the two individuals. In this class of animals 

 the process is almost wholly analogous to fecundation 

 in those plants in which the male and female flowers 

 are on different plants or on different parts of the same 

 plant. In the female fish, a larger number of ova are 

 developed at a certain season of the year, known as the 

 spawning season. Sometimes the number reaches 

 many thousands. At the same time, the testicles of the 

 male fish, which are contained within the abdominal 

 cavity, become distended with developed zoosperms. 

 When the female seeks a place to deposit her eggs, the 

 male closely follows; and as she drops them upon the 

 gravelly bottom, he discharges upon them the zoo- 

 sperms, by which they are fecundated. According to 

 the testimony of an eye-witness, the waters of the North 

 Sea are in some places turbid with the eggs of codfish 

 during the spawning season. 



The process is analagous in some species of frogs. 

 Wlien the female is about to deposit her eggs, the male 

 mounts upon her back, and rides about until the eggs 

 are'all deposited, discharging upon them the fertilizing 

 spermatozoa as they are laid by the female. 



The male frog is enabled to maintain its hold during 

 the long period occupied by the female in laying eggs, 

 by means of an extra development upon the first toe 



