Arca, Linnæus.
08, 9. A. lactea, Linn.—A. barbata, A. Modiolus, A. crinita, A. perforans, 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. Noæ 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. (Arca.)—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.
Avicula.