278 OSTREA. 



Inhabits the Western coasts of Africa, Ascension Island, and 

 China. Chemnitz. Arabia, Sumatra, and the South Seas. 

 Humphreys. 



Shell from three to five inches long, and rather more than half 

 as broad ; thick, ponderous, and clouded with greenish black 

 and violet ; the upper valve is flat, and the lower, which is 

 concave, ends at the summit in a more or less elongated 

 beak. 



orbicularis. 70. Shell orbicular, flatfish, parasi- 

 tical, longitudinally plaited, and transverse- 

 ly wrinkled towards the margin ; margin ob- 

 tuse, and somewhat toothed by the hinge. 



Ostrea orbicularis. Linnceus Syst. Nat. p. 1148.? Chem- 

 nitz, viii. p. 44. t. 74. f. 680. Schroeter Einl. iii. p. 362. 

 Gmelin, p. 3314. 

 Gualter, t. 104. f. G. 



Inhabits the East Indian Seas. Chemnitz. 



Shell about an inch and a quarter in diameter, with the valves 

 unequal, compressed, of a purplish colour, and the inside 

 yellowish. Both Schroeter and Gmelin have quoted Chem- 

 nitz's figure with a mark of doubt, and the Linneean de- 

 scription is so short that this will probably always continue 

 to be rather a doubtful species. 



arborea. 71. Shell rather oblong, transversely 

 wrinkled, with the lower valve thicker and 

 convex, and the upper thin and flat; margin 

 entire. 



Ostrea arborea. Chemnitz, viii. p. 46. t. 74- f. 681. 



Ostrea parasitica. Gmelin, p. 3336. 



Ostrea Rhizophora. Solander's MSS. Portland Cat. p. 



133. lot 2958. 

 Ostrea, No. 111. Schroeter Einl. iii. p. 372. 

 Ostrea. Enc. Method, t. 185. f. 1 to 3. 

 Rumphius, t. 46. f. O. Petiver Amb. t. 19. f. 11. Klein 



Ost. t. 8. f. 17- Favanne, t. 80. f. Q. 

 Variety. Shell rather wedge-shaped, and larger. 

 Le Gasar. Adanson Senegal, p. 196. t. 14. f. 1. 

 Enc. Method, t. 178. f. 1 and 2. 

 Inhabits the Atlantic and Indian Seas, fixed to the roots and 

 branches of trees which grow close to the water. Chemnitz. 

 Molucca Islands. Rumphius. Cura^oa. Humphreys. 



