THE OVARIAN EGG. 276 



tain types, so that the individuals are uniformly 

 hermaphrodites, — yet I firmly believe that this 

 numerical distribution, however unequal it may 

 seem to us, is not without its ordained accuracy 

 and balance. He who has assigned its place to 

 every leaf in the thickest forest, according to an 

 arithmetical law which prescribes to each its al- 

 lotted share of room on the branch where it gro^s, 

 will not have distributed animal life with less 

 care and regularity. 



Although reproduction by eggs is common to 

 all animals, it is only one among several modes 

 of multiplication. We have seen that certain 

 animals, besides the ordinary process of genera- 

 tion, also increase their numbers naturally and 

 constantly by self-division, so that out of one in- 

 dividual many individuals may arise by a natural 

 breaking up of the wbole body into di>tinct sur- 

 viving parts. This process of normal self-division 

 may take place at all periods of life : it may form 

 an early phase of metamorphosis, as in the Hy- 

 droid of our common Aurelia, described in the 

 last article ; or it may even take place before the 

 young is formed in the egg. In such a case, the 

 egg itself divides into a number of portions, — 

 two, four, eight, or even twelve and sixteen in- 

 dividuals being normally developed from every 

 egg, in consequence of this singular process of 

 segmentation of the yolk, which takes place, 



