OSTREA. 279 



Shell from two to six inches long, and the form so much de- 

 pends on that of the wood it adheres to, that it is difficult to 

 find two alike ; the outside is blackish, or sometimes violet, 

 and the inside is nearly white tinged with violet, and has a 

 dark violet muscular impression ; it is generally found on the 

 roots or branches of the Mangifera indica, when they over- 

 hang the water. 



senegalensis. 72. Shell sub-orbicular, with both 

 the valves fJattish and smooth. 



Ostrea Senegalensis. Gmelin, p. 3337- 



Ostrea, No. 118. Schroeter Einl. iii. p. 377. 



Le Rojel. Adanson Senegal, p. 202. t. 14. f. 5. 

 Inhabits the coasts of Senegal, fixed to stones. Adanson. 

 Shell about two inches in diameter, and both the valves are so 



nearly flat that it is not more than a quarter of an inch deep ; 



the outside is of a dark chestnut colour, and the inside dirty 



white. 



denticulata. 73. Shell sub-orbicular, with strong- 

 transverse imbricated wrinkles, and some- 

 what truncated at the hinge, on both sides of 

 which the margin is toothed. 



Ostrea denticulata. Born Mus. p. 113. t. 6. f. 9 and 10. 



Chemnitz, viii. p. 32. t. 73. f. 672 and 673. Shaw Nat. 



Misc. xvi. t. 675. 

 Ostrea edulis, Var. j3. Gmelin, p. 3334. 

 Ostrea, No. 105. Schroeter Einl. iii. p. 369. 

 Le Vetan. Adanson Senegal, t. 14. f. 3. 

 Lister Conch, t. 193, and t. 194. Klein Ost. t. 8. f. 21. 



Enc. Meth. t. 183. f. 1 to 4. 

 Inhabits the sea at the Cape of Good Hope adhering to rocks. 



Shaw. 

 Shell about six inches and a quarter long, and six inches broad; 

 of a dirty or brownish white colour ; there is a considerable 

 difference in the appearance of the shell figured by Chem- 

 nitz, and that of Born, which is very like some of the varieties 

 of O. edulis ; Lister's figures are quoted by Shaw as well as by 

 both these Conchologists, and Lister has marked them to 

 be English shells ; of the figures which are above quoted in 

 the Encyclopedie Methodique, the two first have been 

 copied from Chemnitz, and the two latter from Born, 



