186 BIVALVES. 



white ; the shells are generally thin, fragile, de- 

 licate, and would be ill-fitted to contend with the 

 dangers of their dwelling in the boisterous ocean, 

 had not He who placed them amidst its perils, 

 exercised his compensatory providence, and an- 

 chored them securely in its depths. The animal 

 belonging to these shells, is very similar to the 

 oyster. 



The other family of this genus now bears the 

 name of Terebratula. The shells belonging to it 

 are distinguished by the graceful elegance of their 

 form, which resembles a Grecian lamp, and from 

 hence they are called the Antique Lamps. The 

 concave valve of the Terebratula has its beak pro- 

 duced, curved over the other valve, and per- 

 forated at the apex ; the smaller valve is furnished 

 with two slender shelly processes, which are 

 sometimes short, simple, and recurved ; but 

 sometimes long, branching and crossing each 

 other ; their use is not ascertained, but it is sup- 

 posed that they are supports for the animal. The 

 Terebratulae inhabit the depths of the ocean ; 

 they are parasitical, and are attached to various 

 submarine substances by a tough short stalk 

 which differs from the ligament of the Anomia in 

 being formed of numerous closely united fibres, 

 separating a little at the end, by which they are 

 fixed. The mollusk which inhabits this shell is 

 remarkable for two long fringed arms, which 

 when it is at rest are rolled up in a spiral form 

 within the shell, but which it protrudes when 

 hunger prompts it to seek for food. 



