154 BIVALVES. 



Genus. SOLEN.* PZzmiZ, Solenes. 



RAZOR SHELL. 



Generic Character. Shell bivalve, equivalve, 

 gaping at both ends ; form oblong, transversely 

 elongated ; hinge has a subulate, reflected tooth, 

 sometimes double, not inserted into the opposite 

 valve. Most of the shells are brittle ; some have 

 an internal rib extending from the hinge to the 

 opposite margin. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



There is in general but little difficulty in de- 

 termining the Solenes : they are recognized by 

 their oblong form, their disproportionate breadth, 

 and their gaping at both extremities. A few of 

 the species, however, are oval, and these have 

 their hinge nearly central.*)* 



The history of this genus affords various in- 

 stances of ingenuity in the application of very 

 simple means. The mollusk is furnished with a 

 long cylindrical and pliable leg ; when it wishes 

 to bore a hole for its residence, it extends this 

 instrument from the inferior end of the shell, using 

 it as a pointed shovel to excavate the sand. 

 When the tunnel is partly formed, the animal 



* Plate VII. fig. 3, 4, 5. f Plate VII. fig. 5. 



