REPRODUCTION BY BUDDING 225 



tilising sperms, but divides into two or more individuals 

 or gives off detached buds or reproductive bulbs, which 

 become separate individuals, and only after these and 

 several successive generations of individuals have been 

 thus produced " asexually," by fission or by budding, 

 does a generation appear which produces true egg-cells 

 and sperm-cells and reproduces by their means. Thus 

 it is true that the individuals " budded off" or separated 

 by fission from an asexual parent can be ultimately 

 traced through one or more generations of previous 

 asexual parents to an egg-cell produced and fertilised in 

 the regular way, and with this important modification 

 Harvey's dictum is justified. These facts and the wonderful 

 histories of the animals and plants in which egg-and- 

 sperm-producing generations " alternate " with generations 

 which multiply by fission and budding have only been 

 worked out in detail and by the aid of the microscope 

 during the great century of scientific discovery which lies 

 just behind us. Often the two generations, reproducing, 

 the one by fission, the other by egg- and sperm-cells, are 

 alike in appearance, but often they are very different, and 

 have naturally been supposed at first to have nothing to 

 do with each other. 



Thus some of the little " coralline polyps " and other 

 most beautiful little marine flower-like polyps attached to 

 rocks, weeds, and shells in the sea reproduce by budding 

 and division. But after a period of such growth and 

 such budding they produce on their stalks jelly-fish ! 

 These jelly-fish are budded and thrown off by them, as 

 glass-like swimming bells, which lead an independent life, 

 seize prey, nourish themselves, and grow to a size varying 

 from that of a sixpence to that of a cart-wheel. These 

 " bells " are commonly known as " jelly-fish." They dis- 

 charge thousands of egg-cells into the sea and fertilise 

 them with sperms ! From those fertilised eggs grow young 



IS 



