27 123 



Koh Chuen. 30 Inlhoins (1). Between Koh Kut and Koh Kahdal, 10 fathoms, 

 shells (i'V'ä). S. of Koh Kahdat, 8—10 fathoms, mud (''/ä). 



Long. 4—15 mm. 



Distiihution: — Ceylon (Hanley), Mascat (Brit. Mus.), Red Sea (fossil, Issel). 

 — China (Collect, de l'École d. Mines, Paris). 



All the specimens from the Gulf of Siam are small, but correspond well with 

 Reeve's diagnosis; the valves are thin; in the specimens without an epidermis there 

 is a distinct intercostal-sculpture between the 46 radiating ribs; the angular transi- 

 tion, mentioned as occurring between the hinder and lower margins, is more 

 rounded than is shown in Reeve's figure; the characteristic groove upon the 

 umbones is very pronounced in quite small specimens. 



Area (Scapharca) crebricostata, Reeve. 



Area crebricostala. Reeve, Proc. Zool. Soc. London, XII. 1844, p. 46. 



— — — Conchol. icon., II, Area, Sp. 61. 



— — — Chosse et FiscHEH, Journ. de Conchyl., vol. 37, 1889, p. 292. 



— (Scapharca) crebricostala. Reeve, Martini u. Chemnitz, Conchyl. Cabin., VIII, 2 Abtli., p. 91, pi. 25, 



figs. 3—4. 



— {Anadara — — P. Fischer, Catal. d. Moll, de Ilndo-Chinc, p. 216. 



— — — — L.^MY, Journ. de Conchyl., vol. 55, 1907, p. 253. 



Koh Mak, sand coast {-'l-i). On the coast of Koh Kahdat (^/s). 



Long. 29 — 49 mm. 



Distribution: — Cochin China, Annam. 



I cannot make the great number of ribs (43 — 44), stated by Reeve and Kübelt, 

 agree with the figures given by the same authors, which apparently show only 

 about 35 — 37. Neillier are so many ribs found in the specimens from the Gulf of 

 Siam (in which there are only about 35), unless the most anterior, duplicate ribs 

 are to be counted twice. 



Area (Scapharca) clathrata, Reeve. 



Area chilhrala, Reeve, Proc. Zool. Soc. London, XII, 1844, p. 44. 



— — — Conchol. icon., II, Area, Sp. 48. 



— iAnomalocardia] clathrata, Reeve, Maktini u. Chemnitz, Conchyl. Cabin., VIII, 2 Ablli., p. 17'.l, pi. 



44, fig. 5. 



— {Scapharcai — — Edg. A Ssiith, Rep. Challenger Lamellibranchiata, p. 2()6. 



— {Anadara} — — Lamv, Bull, du Mus. d'Hist. Nat. Paris, 1904, p. 277. 



— - _ _ _ Journ. de Conchyl., vol. 55, 1907, p. 229. 

 Seiipharca iiiminiva, H. Adams, Proc. Zool. Soc. London, 1872, p. 11, pi. 3, fig. 15. 



Area — — Cooke, Ann. and Mag. of Nat. Hist., 5 Ser., vol. 18, 1886, p. 94. 



Common belween Koh Lan and Koh Kut, many specimens in 1—30 fathoms, 

 mud, sand, clay, and shells. 



Long. 3—33 mm. 



Distribution: — Madras, Felidu Atoll (Maldive Archip.), Gulf of Oman 

 (Melvill & Standen), Gulf of Aden, Red Sea, Suez. — Philippines, Amboina, Torres 

 Strait, Mast Head Reef (Queensland). 



16" 



