202 



THE SEA SHORE 



a wide gape at both ends, and consists of two three-lobed valves 

 with concentric furrows. It is so small in proportion to the size of 

 the animal that it encloses but a small portion of the body, and lies 



FIG. 134. THE SHIP WOBM 



at the bottom of the burrow, which is of considerable length often 

 from one to two feet. The animal is very wormlike in form ; and 

 although the shell is so small, yet all the internal organs are 



FIG. 135. 1. Teredo navalis. 2. Teredo norvegica 



enclosed by it. The mantle lobes are united in front, except 

 where the sucker-like foot passes through them ; the gills are long 

 and narrow, and extend into the siphonal tube ; and the two very 

 long siphons are united almost throughout their length. It is also 



