128 UNIVALVES. 



Genus. SERPULA.* PZwraZ, Serpulas. 



CREEPER OR WORM SHELL. 



Generic Character. Shell univalve, tubular, 

 gradually tapering, usually adhering ; cavity 

 often interrupted by dissepimentsf at irregular 

 distances. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



These shells are usually found in very irre- 

 gular and diversified groups adhering to various 

 marine substances. They are invariably tubular, 

 and are either straight, or twisted ; sometimes 

 they are isolated and detached, but are more 

 frequently found in clusters consisting of hun- 

 dreds of spiral tubes curiously interwoven ; they 

 are sometimes curled into a spiral form, but, 

 differ materially from the convoluted shells, as 

 they never have any regular number of whorls, 

 or any appearance indicating that this mollusk 

 is directed in forming these convolutions, by an 

 invariable law. The name is derived from the 

 Latin serpo, I creep, and well designates their 

 tortuous t vermiform appearance. There is very 



* Plate VI. figure 2, 3. 



I* Dissepiments are the partitions in multilocular shells: 

 from the Latin sepes, a hedge, and dis, a prefix signifying 

 division. 



J Tortuous, from the Latin tort ws twisted. 

 Vermiform, from vennis, a worm, and forma, a form. 



