ORDER II. PEDUNCULATE. 25 



PENTELASMIS, Leach. 



Testa quinquevalvis, lateribus compressa, valvis contiguis, inaequalibus, 

 basalibus majoribus, subtrigonis, convexiusculis ; valva dorsali elon- 

 gata, carinata, apice acuto ; valvis superioribus elongato-trapezifor- 

 mibus ; pedunculo plerumque longissimo, lasvi. 



As the number of pieces which serve to compose the shell of the Lepas 

 indicate an important generic character, we adopt the above title in 

 preference to that of Anatifa. The shell of Pentelasmis consists of five 

 pieces, compressed at the sides, and adhering to the internal membrana- 

 ceous integument which contains the body of the animal ; it is supported 

 upon a smooth tendinous peduncle, varying considerably in length, and 

 is found growing in clusters upon timbers, or almost any substance that 



is covered by the sea. 



Example. 



PL XII. Fig. 1, 2. 



Pentelasmis anatifera, Leach, Enc. Brit. Supp., vol. iii. p. 170. 

 Lepas anatifera, Linnaeus. 

 Anatifa Icevis, Lamarck. 

 Anatifa vulgaris, Gray. 

 Pentalepas lavis, De Blainville. 



SCALPELLUM, Leach. 



Testa tredecim- valvis, lateraliter compressa ; valvis contiguis maequali- 

 bus, duodecim lateralibus, subtriangularibus, unica dorsali, elon- 

 gata ; pedunculo squamulifero. 



This genus was also introduced by Dr. Leach, and though included by 



VOL. I. E 



