MEROGONV AND REGENERATION IN RENILLA. 



217 



by side three colonies eight or nine days old, the largest being 

 he product of a whole egg, the smallest that of a fragment about 

 one fourth the size of a whole egg, and the third that of half an 

 egg. These drawings are from camera sketches that show very 

 nearly the true proportions, though owing to the occasional 

 movements of the animals the details had to be drawn free hand. 

 Allowing for slight differences in the state of expansion it may 



FIG. i. In the middle, primary polyp with first pair of buds, reared from an entire 

 j eight days. To the right and left are dwarf colonies nine days old drawn to the 



same scale, from fragments of fertilized eggs, one of approximately one half, the 



other of one fourth the bulk of an entire egg. 



be seen that the dwarfs are very exactly similar to whole colonies 

 of reduced proportions. Beyond this stage it was not found pos- 

 sible to rear the young colonies, even after three weeks, probably 

 owing to the difficulty of providing the animals with suitable food. 

 These results are of some interest as proving that in this case 

 the process of budding does not depend on the attainment of a 

 certain size-limit by the parent stock, but on that of a definite 

 ontogenetic stage, exactly as if the buds were organs of a single 

 individual. It can hardly be doubted that in the ancestral type 



