CIREHIPEDES. 595 



p. 182. tab. xii. f. 2. is the only species known to inhabit 

 the British seas. 



Family 8. The testaceous valves are numerous, greatly 

 exceeding five. It consists of two genera. 



SCALPELLUM. The testaceous valves are thirteen in 

 number, and invest the body. The peduncle is covered 

 with corneous wrinkles, having hairy interstices. The 

 S. vulgare, the Lepas scalpellum of British authors, is the 

 tvpe of the genus. 



POLLICIPES. The testaceous valves are ten in number, 

 with numerous scales investing the base of the peduncle 

 near the body. The P. vtdgc&i&i or Lepan polhceps^ is the 

 type of the genus. 



Tribe II. SESSILE. 



In this tribe the body adheres directly to foreign sub- 

 stances, without the intervention of a tubular stalk. The 

 adhesion is effected in some by the coriaceous cloak, in 

 others by & layer of testaceous matter. The testaceous co- 

 vering usually assumes a conical form. The base is at- 

 tached to rocks or other substances, and the apex is trur- 

 cated and open as an entrance for the water. This cone 

 consists of six valves, closely connected together, but ca- 

 pable of being disjoined by maceration,* especially when 

 young. In old shells, where the valves have attained their 

 full growth, they appear to become cemented together, so 

 that it is very difficult to effect their separation. The 

 valves are so arranged, that one protects the belly, another 

 the back, and two on each side the lateral parts. In some 

 genera, all these valves are so united that the lines of se- 

 paration are not perceptible, while in others the double la- 

 teral valves only are incorporated. Each valve consists of 

 an elevated and depressed portion. The elevated portiorr 

 is conical, with its base at the adhering part of the shell,' 



