BIVALVES: PHOLADS AND SHIP-WORMS. 



215 



Fig. 443. 



Sphserium. 



Northern 



States. 



Fig. 442. Astarte. 

 Coast of New England. 



Fig. 446. Cytherea. Reduced. 

 West Indies. 



Fig. 444. 

 Thyasira. 

 Coast of 



N. England. 



Fig. 445. Sphaerium. 

 Northern States. 



Fig. 447. Mactra. Britain. 



Fig. 449. Tel- 

 lina. Our coast. 



Fig. 450. Tellina. 

 Our coast. 



Fig. 448. Tellina, Britain. 



Fig. 451. Razor-Shell, or Solen. Much reduced. 



Atlantic. 



Both shores of the 



PHOLADS AND SHIP-WORMS. 



Pholads have the shell very hard and rough, like a 

 rasp, and they burrow in all sorts of substances, even 

 in stone. Ship -Worms are long mollusks, looking like 



