COMPOSITE ANIMALS. 101 



statoblasts. Being free, they now pass rapidly to 

 the mature form, attach themselves to some aquatic 

 plant, produce buds, statoblasts, and embryos in 

 their turn, and so complete the circle of their in- 

 dividual and collective life. 



Reverting to the compound or colonial charac- 

 ter by which each member, though of distinct and 

 vital individuality, is yet in some non-vital way 

 organically connected with the whole, w r e observe 

 that the several individuals form for themselves, 

 or, more correctly, arrange themselves into, semi- 

 detached apartments or cells. Generally these 

 open one into the other, and some communication 

 is kept up between each, which is presumably 

 mutually beneficial ; but in some instances these 

 cells are partially, and in others completely, closed 

 against their neighbours. So while living under 

 the same roof so to speak- -social intercourse is 

 suspended, except by contact from without, when 

 the crowns of tentacles of the several individual 

 polypides are protruded together. This is not 

 always the case, for each one has the full power of 

 acting for and by itself so far as its own indivi- 

 dual interests are concerned, except that it cannot 



