19. T. majus, Linn.—T. tuberculatus.—Brit. co. generally; littoral, C. Broad, tuberculated. Large umbilicus.
20. T. lineatus, Costa.—T. crassus, etc.—Channel Isls., Devon. W. Ire., Mc. Smooth, imperforate.
Margarita, or Trochus.
21. M. undulatus, Sowerby.—Turbo carneus, M. striata, etc.—Scotland, 5 to 50 fath., Mc. Striated and undulated.
22. M. helicinus, Fabricius.—Turbo and Trochus neritoideus, margarita, M. vulgaris, etc.—Many Brit. loc.; littoral, C.
23. M. pusillus, Jeffreys.—Lerwick, R., 10 to 40 fath. Minute, white, depressed.
24. M. exilis, Phil.—Skenea Cutleriana.—Guernsey, Skye, etc., R. Globose, striated.
Adeorbis.
25. A. subcarinata, Mont.—(Helix) Trochus rugosus, Cingula subc., etc.—S. Brit, co., Mr. Depressed, keeled.
Scissurella.