14 VIGNETTES FROM INVISIBLE LIFE. 



ment is very remarkable. No one has as yet observed 

 trie actual formation of the colony in this form from 

 the commencement ; but I have frequently seen the 

 colony divide, and this is a most singular process. 

 You have a fine group of, say, forty individuals 

 under observation in a compressorium ; and while 

 you watch, separation takes place not into indi- 

 viduals, but into groups ; so that, instead of one 

 globe of forty, you have two of twenty. No injury 

 is done. It is as if an understanding had been 

 arrived at that one half should go to the right and 

 the other to the left ; and the thing is done in an 

 instant. There are eggs, and young ones are con- 

 stantly being produced; so that the number of 

 individuals forming any one group is not the same 

 for any length of time : the number varying from 

 ten to forty, and all attached to a common centre 

 by their foot-like tail, which is furnished with a 

 suctorial organ for the purpose. To keep the 

 colony together, each member has to contribute 

 something of vital importance. This is of a 

 mucous or gelatinous nature, rather more dense 

 at the centre than at the extremities, and it sur- 

 rounds and keeps all together. This bond of union 



