CIRCULATION OF NUTRIMENT. 13 



and down the tubes, is maintained by means 

 of cilia minute hair-like processes, which by 

 constant waving keep up the circulation. 



Object of circulation. It may be 



thought that this common supply is 

 unnecessary, that each member could find 

 ample food for itself. But there are the 

 immature buds ; the intermediate parts of the 

 structure, that is, the coenosarc, with the 

 Nematophores; and, more important than all, 

 certain other individuals yet to be described, 

 which in consequence of special and important 

 duties devolving upon them, are in many 

 cases rendered incapable of obtaining food 

 for themselves. 



A brief description of these members of 

 the colony will follow. 



Dispersal. It will be evident that if 

 multiplication of the individual be restricted to 

 the method already described, (viz., permanent 

 budding), dispersal of the species could not 

 take place. Nature has therefore allotted to 

 certain individuals of the colony the duty of 

 bearing other and special buds possessing the 



