PATELLA. 1033 



Variety. Shell much depressed. 

 Patelia depressa. Pennant Zool. iv. p. 142. t. 89. f. 146. 

 L'Aile de Chauve-souris. Favanne, i. p. 51 6. t. 2. f. K. 



Common on all the coasts of Europe. Linmms. 



This species differs considerably in size, shape, substance, and 

 colour, and the conical and depressed Varieties run so much 

 into each other that it is impossible to draw any separating 

 line ; the diameter of a full grown shell varies from an inch 

 to two inches and a half, and the depth in some specimens 

 is more than double that of the others with the same diame- 

 ter ; it is most commonly of a dark brownish ash-colour, but 

 young shells are striped in a variety of ways with red, white, 

 and yellow, and these colours appear through the transpa- 

 rent coat on the inside in beautiful variegations ; old shells 

 on the inside are of a horn-colour, and the muscular impres- 

 sion is white ; the number of longitudinal ribs is generally 

 about fourteen, but varies considerably, and the surface in 

 old shells is sometimes nearly level. From Kaemmerer's 

 figures, it appears probable that Gmelin's P. citrina and P. 

 Islandica belong to this species. 



ciERULEA. 39. Shell erose-subangulated with nu- 

 merous unequal striae, and the mside blue. 



Patella caerulea. Linnam Syst. Nat. p. 1259. Born Mus. 

 p. 419. 1. 18. f. 2. Schroeter Einl. ii. p. 412. Gmelin, 

 p. 3697. 

 La Variete des Cotes d'Aunis. Favanne, i. p. 502. t. S. f. 

 D 5.? 

 Inhabits the Mediterranean. Linnceus. 



Linnaeus has not made any reference or addition to the above 

 short character, so that this must probably always remain a 

 doubtful species ; and P. vulgata, in the earlier stages of its 

 growth, often answers the description, as well as the shell 

 which Born has figured : the latter is described to be seven 

 lines long, and five broad, oval, convex, with unequal ribs, 

 and the margin unequally toothed ; summit nearly central ; 

 colour blackish, and the inside blue and shining. 



TUBERCULATA. 40. Shell coulcal, tuberculated, 

 with the posterior end retuse, and the margin 

 toothed. 

 Patella tuberculata. Linmms Syst. Nat. p. 1259. Gme- 

 lin, p. 3697. 

 Inhabits 



