282 OSTREA. 



a quarter, and is Oriental ; the other is much shorter in pro- 

 portion to the breadth, is more flexuose, and agrees with Lis- 

 ter's figures, which are said to have been made from West 

 Indian shells ; the latter has much the appearance of a dis- 

 tinct species, and as such was arranged by Dr. Solander in 

 the Portland Cabinet under the uame of Pedalion torta ; the 

 colour of both is brownish white, or dull ferruginous, and 

 the latter is more strongly wrinkled transversely than the for- 

 mer. 



isognomon. 79. Shell oblong, with the hinge pro- 

 duced, and forming a transverse narrow lobe 

 on one side. 

 Ostrea Isognomon. Linnceus Syst. Nat. p. 1149- Chem- 

 nitz, vii. p. £57. t. 59. f- 584. Schroeter Einl. iii. p. 352. 

 Gmelin, p. 3338. Barbut Verm. p. 56. t. 9- f- 4. 

 Shaw Nat. Misc. xi. t. 439- 

 Pedalion Isognomon. Solander's MSS. 

 Variety A. With the lateral lobe very long. 

 Perna. Enc. Method, t. 176. f. 1. 

 Rumphius, t.47. f. I. Petiver Amb. t. 20. f. 11. Klein 

 Ost. t. 8. f. 15. Seba, iii. t. 91. f. 6. Regenfuss, ii. t. 

 8. f. 11. Favanne, t. 42. f.Bl. 

 Variety B. With the lateral lobe short. 



Perna Tranquebarensis. Leach Zool. Misc. p. 142. 1. 1 14. 

 Perna. Enc. Meth. t. 175. f. 4 and 5. 

 Gualter, t. 97. f. A. Seba, iii. t. 91. f. 8. Knorr, iv. t. 

 10. f. 1 and 2. 

 Inhabits the coasts of Amboyna, Rumphius. Ceylon, and the 

 Molucca Islands. Chemnitz. Luconia, Pulo Condore, 

 China, and the Philippine Islands. Humphreys. 

 Shell from five to seven inches long, and about one inch and 

 three quarters broad ; of a blackish violet colour, and the in- 

 side pearly ; it bears some resemblance to O. Malleus, but 

 has only one linear lobe, and the hinge is widely different, 

 being more like that of an Area. In the variety the lateral 

 lobe is either very short, or sometimes almost wholly wanting, 

 and the shell is frequently considerably bent. 



ephippium. 80. Shell sub-orbicular, ftattish, much 



produced, and rounded on one side, and the 



hinge straight. 



Ostrea Ephippium. Linnaus Syst. Nat. p. J 149- Born 



Mus. p. 114. Chemnitz, vii. p. 245. t. 58. f. 576. 



