65 IBl 



lata, Horn (and var. Forskåli, Chemn.), were taken in Pliocene Deposits in Egypt 

 "in the Lake Deposits of Wadi Nalrun at tlie hill known as Moluk." ' 



Ostrea hyotis L. 



Mtjlilus Ilijotis, I.INNK, Syst. Nat., ed. 10, 1758, p. 7(14, No. 207. — ed. 12, p. 1155, No. 244. — Mus. Ludov. 



Ulr., p. 538, No. 129. 

 Ostriva bi/otis, — Reeve, Conchol. icon., XVIII, 1870, Ostrœa, Sp. 7. 



Var. imbricata, Lamarck. 



Ostrea imbricata, Lamarck, Hist. nat. d. anim. s. vert., VI, 1 part. 1819, p. 215, No. 4fi. — éd. 2, VII, 1836, 



p. 235, No. 46. 

 Ostrœa — — Reeve, Conchol. icon., XVIII, Ostra-a, Sp. 36. 



Koh Kram, 30 fathoms ('/a). S. of Koh Chuen, 30 fathoms, shells (''/j). Coast 

 of Lem Ngob (1). S. of Koh Kahdat, 8 — 10 fathoms, mud (1). E. of Koh Mak, 20 

 fathoms, mud (1) (Singapore; Sv. Gad. '/a). 



Specimen from Koh Kram: long. 74 mm., alt. 46 mm. 



— — Koh Kahdat: long. 33 mm., alt. 49 mm. 



— — Koh Chuen: long. 21 mm., alt. 24 mm. 



— — Koh Mak: long. 57 mm., alt. 49 mm. 



Distribution: — 0. hyotis has been recorded from : — Ceylon, Gulf of Manaar, 

 Gulf of Aden, Seychelles, Amirautés, Mauritius, Zanzibar. — Poulo Condor, China, 

 Loo Choo Isis., Japan, Philippines, Moluccas, Viti Isis. 



0. imbricata has been recorded from : — China, Japan, Java, New Guinea, and 

 by Melvill & Standen from the Persian Gulf and the Mekran coast. 



Since Deshayes (in the second ed. of Lamarck, Anim. s. vert.) wrote regarding 

 0. imbricata that "Cette espèce est inutile, elle a été faite avec une variété jaune de 

 la suivante (0. hyotis, Ch.); il faudra donc les réunir sous la dénomination d'Ostrea 

 hyotis," some later authors have upheld the specific distinctness of both the species 

 (Dunkek, Reeve, Pilsbry), some regard them either as varieties or as the same 

 species (Küster, Hanley, Mørch). 



0. inermis, Sow., is no doubt synonymous with 0. imbricata, Lam. 



Ostrea rivularis, Gould (Lischke). 



Ostrea riuularis, Gould, Proceed. Boston Soc. Nat. Hist., vol. VlII, 1861, p. 39. 



— — — Lischke, Japanische Meeres Conchyl., I, 1869, p. 176, pi. 14, figs. 2—3. 



Gulf of Rayong, 7 — 10 fathoms, sand and mud (i/a). S. of Koh Samit, 20 

 fathoms, mud ('/a). Coast of Lem Ngob (1). Sound of Koh Chang, 5 fathoms, soft 

 clay (4). E. of Koh Mak, 20 fathoms, mud ('/a). Between Koh Kut and Koh Kahdat, 

 10 fathoms, shells (one specimen, and some young odd valves). Strand of Koh 

 Kahdat (-/a) (Singapore, shallow water, one specimen; Sv. Gad). 



' R. Bullen Newton, On some Pliocene and Post-Pliocene Shells from Egypt (The Geological 

 Magazine. New Ser., dec. IV, vol.6, 1899, p. 402, pi. 19, figs. 1—5). 



U. K U. ViilensU SeUk. Skr., 7. RiuUke, naturvideiisk. og niiitliem. Afd. V. 3. 21 



