126 UNIVALVES. 



tenths of an inch, and one fourth as much at the 

 smaller end. 



It is commonly found on our coasts, particu- 

 larly those of the West of England. The ani- 

 mal is very muscular, its shape is like its conical 

 shell, and it has a mantle with a fleshy collar 

 through which it can protrude its head and foot. 

 The head is furnished with jaws, and lips bear- 

 ing teeth. 



GENUS. SERPULA.* 



CREEPER OR WORM SHELL. 



Generic character. Shell univalve, tubular, 

 gradually tapering, usually adhering ; cavity often 

 interrupted by imperforate dissepiments,! at ir- 

 regular distances. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



These shells are usually found in very irregu- 

 lar and diversified groups adhering to various 

 marine substances. They are invariably tubular, 

 some straight, some twisted ; sometimes they are 

 isolated and detached, but more frequently in 



* Plate VI. figures 2, 3. 



t Dissepiments are the partitions in multilocular shells: fromthft 

 Latin sepes, a hedge, and dis,-a prefix signifying division. 



