Panopæa. Burrows in mud.
21. P. norvegica, Spengl.—P. glycimeris, P. arctica.—Scarborough, Zetland (90 fath.), Rr. Quadrate.
21*. P. Aldrovandi, Lamk.—Cornwall, one specimen, Jeffreys. Oblique.
Corbula. Dredged in mud and sand.
22. C. nucleus, Lamk.—C. striata, Mya, and C. inæquivalvis.—Dublin, Torquay, Forth, 4 to 80 fath., C. Valves unequal, beaked.
23. C. rosea, Brown.—Weymouth, Rr. as Brit. Valves not beaked.
24. C. ovata, Forbes.—Isle of Man, Rr. Oval, truncated at end.
Sphænia. Burrows in foliaceous shells.
25. S. Binghami, Turt.—Corbula B.—Torquay, Guernsey, Swansea, Forth, etc., R.
Neæra. Lives incrusted in sand.