244 



the others but ascends and fonns the outline of the shell 

 into a truncated cone, with the mouth at the top subla- 

 teral. The groove and central cavity are in this state 

 less distinct, the latter generally obliterated. Rare. 

 In deep water. 



VERMILIA SERRULATA. Flem. in Edin. Phil. J. 

 vol. 12. SERPULA. S. Fl. in Ed. Ency. 7. p. 67. t. 

 204. /. 8. Translucent, triangular, with a serrated 

 dorsal ridge; lid single, concave, with a smooth 

 margin. 



BALANUS CRANCHII. Leach. Enc, Brit Sup. 

 Depressed, conical, very spreading at the base ; valves 

 darker or paler purple, crowded with coarse raised 

 radiating striae ; aperture very small in proportion ; 

 walls at the base, cellular. Diam. I. Rare. Tenby. 



MACTRA ELLIPTICA. Brown. III. Forbes Mai. 

 Mon. p. 48. Maca. Aber. p. 289. Subelliptical. 

 very thin, yellowish white, smoothish, somewhat glossy, 

 with faint and very delicate concentric striae, rather con- 

 spicuous lines of growth and slight indications of 

 radiating 'striulae ; umbones prominent, pointed, recurved 

 and nearly central : posterior slope convex, the anterior 

 less so and forming an obtuse angle with the arched 



