MOLLUSCA 165 



Pholas truncata Say 



(Barnea truncata Say) 



PLATE XV. Fig. 5 



Smaller than the above and more truncate; bur- 

 rows in mud and peat and found between Maine and 

 the Gulf of Mexico. The shell is fairly common in 

 New Jersey, especially along Delaware Bay beaches ; 

 it has been observed burrowing into a log washed 

 ashore at Cape May Point. (September 21, 1928). 



Zirphaea crispata Linne 



Somewhat similar in general appearance to the 

 above but with a prominent furrow which divided 

 each valve into two parts. 



A northern shell living in hard clay or rocks; 

 very rare in New Jersey. 



Teredo navalis Linne (Ship Worm) 



Fig. 26 



One would naturally expect that the ship worm 

 was an annelid worm. However, it is really a bi- 

 valve mollusk of a very modified type. It is worm- 

 like in form and lives in a shelly tube not unlike 

 that of the worm Eupomotas dianthus. It does how- 

 ever, have a very small shell (14 inch long) at the 

 wider end of the tube. At the other end of the tube 

 there are two calcareous structures known as pallets 

 which are used to close the tube. 



Ship worms bore into submerged wood and are 



