98 NATURAL HISTORY OF OUR SHORES 



in the form of a small, flattened snail shell. Some of them 

 can be seen adhering to the rock in the photos. 



If some of these little ones are placed in a bottle of sea- 

 water, and viewed with a pocket lens, the arrangement of 

 plumes and the operculum, as described, will be readily 

 seen, as the little worm is active, and quickly protrudes 

 when under water. 



Another family of the tubiculous worms are the 



Terebellidce. On many parts of the shore where there 

 is a mixture of sand and gravel, near low-water level, may 

 frequently be seen large patches of what looks like a forest of 

 miniature trees, their trunks and branches coated with sand 

 and gravel. These are the tubes of Terebella conchilega, 

 the commonest species. 



The tubes are made up, like those of Sabella arenosa, of 

 cemented-together fragments of the constituents of the 

 surrounding ground, but they have branched ramifications 

 at the top. 



The inmate is a limp and fragile worm, something on the 

 plan of the foregoing, but instead of circlets of plumes it 

 has two bright red tufts, the branchice or breathing organs, 

 and a large series of threadlike tentacles. In some species 

 these thread tentacles can form a network for more than 

 a foot around the animal. The little branches at the top of 

 the tubes serve to spread these out upon, where they look 

 like the stems of the Lesser Dodder spreading over a furze 

 bush. 



I have not seen a description of these threads, but have 

 often examined them, and I make them out to be tubes 

 open all along one side, and the interior to be lined with 

 cilia, so that any little organism touching them can be 

 taken in at any point, and then carried by the movement 

 of the cilia to the worm's mouth. One of these worms 

 and its branched tube are shown in Fig. 38. 



A large and beautiful Terrebellid is Amphitrite Ed^vardsii. 



