274 THE PRINCIPLES OF Part II. 



or by the spontaneous movements of the stamens ; and 

 with the Algae, &c, by the locomotive power of the 

 antherozooids. With lowly-organised animals perma- 

 nently affixed to the same spot and having their sexes 

 separate, the male element is invariably brought to 

 the female ; and we can see the reason why ; for the 

 ova, even if detached before being fertilised and not 

 requiring subsequent nourishment or protection, would 

 be, from their larger relative size, less easily transported 

 than the male element. Hence plants 14 and many of 

 the lower animals are, in this respect, analogous. The 

 males of affixed animals having been thus led to emit 

 their fertilising element, it is natural that any of their 

 descendants, which rose in the scale and became loco- 

 motive, should retain the same habit, and should closely 

 approach the female, so that the fertilising element 

 might not run the risk of a long transit through the 

 waters of the sea. With some few of the lower ani- 

 mals, the females alone are iixed, and with these the 

 males must be the seekers. With respect to forms, 

 of which the progenitors were primordially free, it is 

 difficult to understand why the males should inva- 

 riably have acquired the habit of approaching the 

 females, instead of being approached by them. But 

 in all cases, in order that the males should be efficient 

 seekers, it would be necessary that they should be en- 

 dowed with strong passions ; and the acquirement of 

 such passions would naturally follow from the more 

 eager males leaving a larger number of offspring than 

 the less eager. 



The great eagerness of the male has thus indirectly 



14 Prof. Sachs ('Lehrbuch der Botanik,' 1870, s. 633) in speaking of 

 the male and ft male reproductive cells, remarks, " verlialt sich die eine 

 " bei der Vereinigung activ, . . . die andere erscheint bei dur Verein- 

 " igung passiv." 



