EY J. C. COX, M.D., F.L.S. 131 



between these denticles is of a deep purple brown ; the hinge 

 margin is straight and squared at the ends. Upper valve very- 

 flat, cinnamon-tinted within, variegated with purple between the 

 denticles and margin lobes ; lower valve thick and whitish within. 



This is the species which Mr. George French Angas erroneousl}^ 

 referred our common Eock Oyster to when he wrote his valuable 

 list of the Marine Mollusca of Port Jackson Harbour and the 

 adjacent coast. 



5. OsTREA CRisTAGALLi, Linneus. 



I am doubtful if this species should be included with the 

 edible oysters, it is said to be freely eaten in Northern Queens- 

 land by the natives, and also in the South Pacific Islands, but I 

 have not had any experience of it myself. I have specimens of 

 it from Port Denison and other of the Northern Queensland 

 Ports, and it is abundant in the Solomon and other Islands of 

 the Pacific. It is known as the Cock's Comb Oyster. Figured 

 in Eeeve's Conch. Icon., PI. xi.. Species 22, Ostrea. 



6. Ostrea imbricata, Lamar ch. 



Anim. sans Yert. Ostrea, No. 46. Figured in Eeeve's Conch. 

 Icon., PL xvii., sp. 36, a. b. 



This Chinese species has recently been procured in fine con- 

 dition at Port Denison, Queensland. I am not aware if it is an 

 oyster which is used much as an article of food, but judging from 

 its shell the occui)ant should be a delicious morsel. 



It is a large foliaceous, thin shell, loosely radiately plicated, 

 pinkish and ornamented with irregular purple spots, other shells 

 are of a pale fawn, tinted with reddish brown ; the lower valve 

 often foliaceous. 



7. Ostrea virescens, Angas. 



Described in the Pro. Zool. Soc, Lon., 1867, p. 911, pi. xliv, 

 fig. 13. 



