18 



longitudinally, often smoother ; aperture large, inner 

 margin ridged transversely; operculum quadrivalve, 

 not striated, angulated, erect. Dorset, fyc. Diam. 0,40. 



B. SCOTICUS. LEPAS S. Wood. G. C. t. 6./. 3. p. 

 10. Turt. D. p. 76. Conical, with six valves, dirty 

 white ; valves longitudinally ribhed, unequal, striated 

 transversely at the base. t.. 1. Scotland on My- 

 tilus modiolus, Lin. This brief description is all that 

 is given by Mr. Wood, saving that he farther states 

 that the operculum resembles that of Tintinnabulum, 

 I regard it as of rather doubtful distinctness. 



B. PUNCTATUS. Dor. Cat. p. 25. t. 1. /. 10. (not 

 Lam: nor Brug.) Mont. p. 8. t. 1. f. 5. LEFAS P. 

 Wood. G. C.p. 46. D.p. 15. A. Turt. D. p. 78. 

 An L. CORNUBIENSIS: Pen. 4. p. 73. t. 37. /. 6. ? 

 An B. CRENATUS ? Brug. p. 168. Very rugged, 

 brown, valves indistinct, usually punctured, base 

 spreading but little and scarcely broader than high ; 

 anterior valve always provided with two connecting 

 shoulders ; operculum of four valves, the upper one with 

 a few longitudinal ridges, (the edges of the superior and 

 anterior valves generally closely united at the top, 

 indented or notched, punctated and interlocking. 

 S. Devon, common on Patella Vulgata. 



B. COSTATUS: Mont. p. 1 1. LEPAS C. Don. t. 30. 



