28 Natural Salvation. 



only real, distinct type of life which exists, or has ever 

 existed on the earth's surface. Since all the metazoons 

 are but more or less well-organized and well-perfected 

 confraternities of cell life, where the individual lives of 

 millions of cells are unified in a single, larger personality. 



Many of the polyzoa are suggestive of the manner in 

 which multicellular organisms started. In paludicella we 

 find cells joined together, as joints or sections of the 

 branches of a minute tree-like growth, attached to stones 

 in streams. It is a tree in miniature ; the cells grow 

 forth, one beyond another, offspring above parent cell, but 

 otherwise have little connection one with another. It is 

 simply an arboriform colony, or zoarium. Other polyzoa, 

 like mucronella, form mat-like disks on stones in water, 

 the cells lying in contact merely. 



In certain of the zoaria of polyzoa, however, a con- 

 siderable degree of individualization is exhibited with 

 division of labor among the cells. In christatella mucedo 

 the cells not only adhere, but the whole colony crawls 

 with considerable facility from one water weed to another. 

 Kinetoskias is another zoarium where the colony has 

 arrived at the point of differentiation of function. Adeona 

 presents an equally interesting example of a simple colony 

 of unicells on its way toward a many-celled organism. 



Among the hydrozoa, siphonophora affords an example 

 where a floating colony of unicells has taken definite form 

 and organized its individual cells to work for the common 



