132 EDIBLE OYSTEES FOUND ON THE ArSTEALTAN COAST, 



A suborbicular solid inequivalve shell, with the margins of the 

 shell crenulately frilled, of a greenish-olive colour within, paler 

 at the margins ; the upper valve smallest, flattened, radiately 

 plicate and laminately scaled, about If inches long and 1| broad. 

 Found attached to rocks and Madrepores at the edge of low spring- 

 tides at Watson's Bay, Port Jackson. 



This species is also well figured in Reeve's Conch. Icon. Mon., 

 Ostrea, PI. xi., sp. 23, fig. 23. 



This is not a species likely ever to be of any commercial value, 

 it is rare, and its green internal hue is uninviting. 



8. Ostrea circumsuta, Gould. 



United States Expedition. Figured in Eeeve, Conch. Icon. 

 PI. xxvi., sp. 64, fig. 64, a. b. 



The habitat given by Eeeve, with doubt, of this species, is 

 Massachusetts, but the fact that it is not included in the 

 Marine Shells cf the United States by Tryon, pretty clearly 

 proves that this locality is a mistake. Mr. Gr. F. Angas was the 

 first to point out that the species is found on those shores, he 

 gives Botany Bay as the exact home of this shell, which statement 

 I have much pleasure in endorsing ; it is found there attached to 

 rocks, not abundant, but specimens can easily be procured. It is 

 about two inches long and one broad, and derives its name from 

 the stitch-like appearance of the denticles in the upper valve, and 

 corresponding indentations in the inner surface of the margin of 

 the lower valve. It is whitish or purplish externally, plicated 

 at the margin and tinted with purple or green within. 



9. Ostrea discoidea, Gould. 



Figured in Peeve, Conch. Icon., PL xiii.. Fig. 26, sp. 26. 



A rounded, flattened, finely striated, whitish-brown species, 

 rayed with pale purple; valves almost equal, the lower one 

 convex and the upper one much compressed ; the hinge is com- 

 paratively small and contracted. 



