LIST OF PLATES. Vll 



2. Venerupis Irus, a rock-boring bivalve. 



3, 4. Corbula nucleus. 



5. Pmidora obtusa. 



6. Pandora rostrata. 



7. Lyomia Norvegica. 



Plate V. 

 MUD BURROWERS. 

 These live in mud and sand, witli tlie ends of their tubes some- 

 times protruding above the holes ; at other times so deeply 

 immersed as to leave only an indication on the surface. 



1. Liitraria elliptica. 



2. My a truncata. Tliis bivalve has a spoon-shaped process in 



the hinge of one valve. 



3. Tanopma Norvegica, found about the northern coasts of Scot- 



land as well as in Norway. 



Plate YI. 

 RAZOR-SHELLS. 



1. Solecurtus candidus, covered with a dark greenish epidermis, 



and diflPeiing from the tnie Solens in having a central hinge. 



2. Solen ensis, the tme Eazor-sheU, having the hinge at one end. 



3. Cei'atisolen legumen, with a singularly shaped foot. 



Plate YII. 



1. Psammobia tellinella. 



2. Tellina crassa, or Thick Tellen. 



