TOILERS IN THE SEA. 291 



CHAPTER IX. 



SEA-MAT MAKERS. 



ONE of the most common experiences of a sea- 

 side collector is to pick up a dead frond of the 

 larger sea-weeds, or a tuft of the smaller ones, wholly, 

 or only partially, invested with an encrusting patch, 

 of a dirty-white-colour, evidently of quite a different 

 character from the sea-weed on which it has become 

 established ; and, if examined by the pocket-lens, will 

 be found to consist of a great number of horny cells, 

 each with a small opening or mouth, and, in some 

 species, furnished with long rigid bristles, so as appear 

 even to the naked eye to be hairy. These were once 

 the homes of minute marine Polyzoa, kindred to the 

 sea-mats, the latter differing from the former in not 

 encrusting other substances, but forming a kind of 

 frond, or tuft of fronds, of their own. The Polyzoa, 

 or as some persons persist in calling them, the Bryo- 

 zoa, are for the most part marine, although there is a 

 small group, well known to pond-hunters, which in- 

 habit fresh water ; in all of them the animals are 



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