As given by Lamarck, is a natural and well-defined family. It is too well known to require description. It fixes itself to other bodies by the laminæ of the whole surface of one valve, and generally remains immoveable, exhibiting no other signs of life other than that of opening its valves to receive nutriment. Shell irregular, inequivalve, inequilateral, exterior roughly foliaceous, interior somewhat pearly; the left or inferior valve larger, deeper, and adhesive, its summit prolonging with age in a sort of heel, the right or superior valve smaller, more or less in the form of a lid; hinge without teeth; ligament short, sub-interior, inserted in an oblong cardinal cavity, increasing with the summit; muscular impression single and sub-central. Ostrea edulis. O. hippopus. O. borealis. O. Adriatica. O. cochlear. O. cristata. O. gallina. O. numisma. O. lingua. O. tulipa. O. Brisiliana. O. scabra. O. rostralis. O. parasitica. O. denticulata. O. spathulata. O. cornucopiæ. O. cucullata. O. doridella. O. rubella. O. limacella. O. ruscuriana. O. Virginica. O. Canadensis. O. excavata. O. mytiloides. O. sinuata. O. trapezina. O. tuberculata. O. rufa. O. margaritacea. O. gibbosa. O. Australis. O. elliptica. O. haliotidæa. O. deformis. O. fucorum. O. plicatula. O. glaucina. O. fusca. O. turbinata. O. crista-galli. O. erucella. O. folium. O. labrella. O. imbricata. O. hyotis. O. radiata. _O. edulis._ The eatable Oyster. Pl. 16, fig. 5.