PLATE VIII. 



Nucula, Linn. 

 Fig. 



1. N. nucleus, Linn. {Area.) — N. margaritacea, Glycimeris argentea. 



— Brit. co. generally, 7 to 90 fath., C. Thick, obtuse ; beaks ter- 

 minal. 



2. N. decussata, Sowerby. — N. sulcata, N. Tolii. — Hebrides, Loch 



Pyne, Dublin Bay, 30 to 50 fath., Mr. Large, striated; beak 

 not terminal. 



3. N. RADIATA, Hartley. — N. and Area nucleus and radiata. — Torbay, 



Milford Haven, Arran, etc., 10 to 70 fath., Mc. Prolonged an- 

 teriorly, rayed. 



4. N. nitida, Sowerby. — N. nucleus, var. — Numerous British loc, 1 



to 35 fath., C. Shining, ends rather pointed. 



5. N. tenuis, Montagu, (Area.) — North British co., 40 to 100 fath., 



sand, C. Thin, inner edge not crenated; beak terminal. 



Leda, Sckum. Beaked behind. 



6. L. caudata, Donovan, {Area.) — Area and Nucula minuta and ros- 



trata. — North co., C. ; south co., R. 10 fath. to deep water. 

 Ridged. 



7. L. pygm^ea, Munster, {Nucula.) — N. and!/, tenuis, gibbosa, an&len- 



ticula. — Skye, Hebrides, Croulin Isl., 25 to 50 fath. Minute, 

 smooth. Size (omitted) one-fifth of an inch. 



Arca, Linnaus. 



8. 9. A. lactea, Linn. — A. barbata, A. Modiolus, A. crinita, A. per- 



forans, A. Gaimardii, var. f. 8 ; A. Quoyi, var. f. 9. — Penzance, 

 Ilfracombe, Bantry Bay, Guernsey, etc. Adhering to shells and 

 stones, 15 to 20 fath., C. Beaks approaching, radiately striated. 



10. A. tetragona, Poli. — A. Nocb and imbricata. — Many Brit, loc, C. 



(12 to 50 fath.). Broad area between beaks. 



11. A. raridentata, S. Wood. — A. pectunculoides. — Skye, Hebrides, 



etc., Scot. Cape Clear, 40 to 60 fath., Mr. Minute, teeth few. 



12. A. nodulosa, Ph. — E. Zetland, Shetland Isls., Rr. 



Pectunculus. 



13. P. glycimeris, Linn. {Area.) — A. and P. and Glycimeris pilosa, 



orbicularis, undata, and marmorata. — Brit. co. generally, 15 to 

 60 fath., C. 



Limopsis. 



14. L. pellucida, Jeffreys, Ann. Nat. Hist. Jan. 59.— Dredged in 



sand at Guernsey, Rr. 



