123 



covered with numerous raised pustular dots, the under 

 valve flat and marked with concave dots; heaks ter- 

 minal. 1. Teignmouth, fyc. on Crabs, fyc. 



A. CYLINDRICA. Turt. D.p. 6. Turt. B. p. 232. 

 P.p. 396. A. CYMBIFORMIS. Lin. T. 8. p. 104 t. 

 3./. 6. Mont Sup.p.64. An. A . PYRIFORMIS. Lam.? 

 Oval, somewhat cylindrically convex and transversely 

 rugged, but often smooth, brownish, narrower towards 

 the beak which curves over the under valve and ends in 

 an obtuse point. i...i. On Fuci and Sertularioe. 



A. STRIOLATA. Turt. B. p. 233. F. p. 396. 



Oval, somewhat cylindrically convex and striated lon- 

 gitudinally, with the beak curved backwards. Roots of 

 Fuci. 



A. ACULEATA. Gmel. 3346. Ch. f. 702. Mont. 

 p. 157. t. 4./. 6. Pen. 4. p. 233. D. p. 288. 

 Turt. D. p. 4.F. p. 396. 7V. B. p. 233- Flat, 

 rounded or oblong, sometimes truncated at the top, 

 brown or whitish, anned with numerous radiating 

 prickly striae on the upper valve. 0,40. Dover, fyc 



A. FORNICATA. Lam. 6. Turt. B. p. 234. t. 18. 

 /. 1,2,3. F. p. 396. Orbicular or inclining to 



