LEPAS. 41 



WRINKLED ACORN. 

 PL 6./. 4. Dr. Coombe. 



7. Lepas rugosa. L. testa subcylindrica, operculis acutissimis. Linn. 

 Trans. 8. p. 25. t. 1. f. 5. 



Shell somewhat cylindrical ; operculum very sharp-pointed. 

 Lepas borealis. Donov. Br. Shells, 1. 160. 



Balauus rugosus. Pultn. in Hutch. Dorset, p. 25. t. 2. f. 10. Mont. 

 Test. Brit. p. 8. 



This shell has six triangular valves, so far separated 

 at top as to leave the aperture almost as wide as the 

 base. The aperture is of a rhomboidal shape, with the 

 inside margin ridged transversely. The valves within 

 are strongly grooved longitudinally. The shell exter- 

 nally is nearly smooth, and of a whitish colour lightly 

 stained with purple. 



The specimen figured in pi. 6 is foreign ; but it is 

 described as a British shell by Mr. Montagu, who 

 found it with irregular compartments, wrinkled or stria- 

 ted longitudinally. The operculum has four rough 

 angulated valves, terminating in four distinct points, 

 inclining backwards. 



NARROW-MOUTHED ACORN. 

 PI. 6. f. 5. Mrs. Mawe. 



8. Lepas angustata. L. testa elongata leevi sexvalvi, apertura angusta, 

 operculo minimo. Linn. Syst. Nat. Gmel. p. 3212. 



Shell elongated, smooth, of six valves; the aperture narrow; opercu- 

 lum very small. 



Balanus perforatus, B. testa semi-ovata, longitudinaliter striata, violacea, 

 apertura coarctata minima, radiis filiformibus. Brug. Encyclop. 

 Method. Hist. Nat. torn. 6. p. 167. 



Lepas ore angustiore, apertura coarctata. Chem. Conch. 8. t. 98. f. 835. 

 Encyclop. Method, pi. 164. f. 12. 



This shell is of a very conical shape, owing to the 



