POLLICIPES. 



TESTA multivalvi, lateraliter subcompressa, pe- 

 dunculo squamiilifero affixa; valvis quinque 

 superioribus majoribiis, inferioribus minimis, 

 omnibus superne acutis. 



Separated by Dr. Leach from the other pedunculated 

 Cirripedes, and particularly distinguished from it by its 

 squamuliferous peduncle, as well as by the form and posi- 

 tion of the five larger valves. The Genus is composed of 

 a few species, of which the two principal were the Lin- 

 nean Lepades Pollicipes and Mitella; to them may be 

 added Pollicipes villosus of Leach, and we shall then have 

 enumerated all the species with which we are at present 

 acquainted : for we cannot follow Lamarck in adding the 

 Lepas sccdpellum to this Genus, because we are perfectly 

 satisfied that there are equally good characters to sepa- 

 rate this latter as a Genus from Pentelasmis, (Lamarck's 

 Anatifa ) as there are to distinguish Pollicipes from Pen- 

 telasmis, 



Pollicipes may be described as a shell consisting of 

 many valves, forming together a somewhat laterally com- 

 pressed irregularly conical body, fixed upon a squamu- 

 liferous peduncle, which seldom exceeds two inches in 

 length : the five upper valves are considerably larger than 

 the rest ; of these the anterior pair are placed one on 

 each side of the opening, they are conical, elongated, 

 and their upper points are reflected backwards : the cen- 

 tral, which is also the terminal pair, is the largest, each 

 valve is of the shape of an elongated trapezium, having 

 an acute angle at its superior extremity: the dorsal 



