94 ALONG THE FLORIDA KEEF. 



"These," said the doctor, "are the tentacles 

 and heads of a worm that builds its lime tube 

 on the rock when the latter is small ; then, as 

 the coral grows around it, the tube is completely 

 enveloped. As fast as the coral encroaches on 

 the worm it throws out new courses of masonry, 

 keeping pace with the Astrcea, and vying with 

 it in the exhibition of beautiful tufts of plumes." 



Another variety over which they passed had 

 a golden-yellow cup-like series of plumes, con- 

 trasting brightly with the brown tints of the 

 Astrceas. 



" The worms are not the simple creatures 

 they are supposed to be," said the doctor. 

 u Look at this evidence of intelligence," reaching 

 over and grasping what appeared to be a bit of 

 weed. 



It was the tube of a worm which was stand- 

 ing in the sand. The door was a shell, skill- 

 fully inclosed in the masonry, while also fastened 

 to it and falling over was a blade of marine 

 grass (Zosterd), so that no one would have sus- 

 pected the true nature of the nest. At the doc- 

 tor's request the boys went overboard and 



