B. ALCYONII. LEPAS A. Turt. D. p. 76. Some- 

 what conic, white or brownish white, with six very 

 unequal and irregularly sized valves which terminate 

 in rather acute points; aperture large, oval or roundish, 

 lid of four valves, the two uppermost smooth, pointed, 

 gaping a little at top and protuding in the middle into 

 a kind of keel. Diameter and height \. On Alccy- 

 onium and Flustra, Weymouth. 



GENUS ACASTA. 



Sessile, oval, subconical, composed of separable pieces, 

 valves six, laterally united, unequal ; the basis an 

 orbicular, internally concave, testaceous lamella; 

 operculum quadrivalve. 



A. MONTAGUI. Leach. Cirrhip. Lam. 1. BALA- 

 NUS SPONGEOSUS. Mont. Sup. p. 2. t. 7.f. 4, 5, 6. 

 Bl.t.SS.f. 3. Dor. Cat. p. 25. LEPAS S. Turt. 

 D.p. 78. D. p. 27. Wood. G. C. p. 47. Livid 

 brown with a purple tinge towards the summit ; valves 

 six, wrinkled, sharply pointed, the three anterior the 

 broader and shorter; operculum quadrivalve, the two 

 anterior pieces rough with decussated striae, the two 

 posterior longer and a little hooked forwards. 3. 

 Portland Reach) in sponge, rare. 



GENUS PYRGOMA. 

 Sessile, univalve, subalobular, ventricose, convex alove, 



