104 



Yoldia tenella, Hinds. 



Nucuhi tenella, Hinds, Proc. Zool. London, XI, 1843, p. 99. 



— — — Hanley, Kec. bivalve shells, p. 370, pi. 19, fig. 47. 



Leda _ _ _ Monogr. of the fam. Nticiilidw (Soweuby, Thesaurus Conchyl., 111) p. 137, 



No. 56, pi. 1, lig. 15. 

 Yoldia — — Reeve, Conchol. icon., XVIII, Yoldia, Sp. 4. 



Koh Chuen, 10—15 fathoms ('/a). West of Koh Chuen, soft clay and mud 

 (1 + Vs). East of Koh Mak, 20 fathoms, mud {'i-j). W. of Koh Kul, 3(1 fatlioms, 

 sand and mud (-'/j). N. of Koh Kut, 10 fathoms, mud ('/a). 



Long. 4 — 11 mm. 



Distribution:— Singapore, Gulf of Oman (Melvili. ä Standen). 



Yoldia serotina, Hinds. 



Nucnla serutina, Hinds, Proc. Zool. Soc. London, XI, 1843, p. 99. 



Leda — — Sdwebby, Thesaurus Conehyliorum, III, 18G6. Monogr. of the fam. Nncitlida' by 



Hanley, p. 136, No. 54, pi. 1, figs. 19—21. 

 Yoldia — A. Adams, Reeve, Conchol. icon., XVIII, Yoldia, Sp. 5. 



Leda lepida, - Proc. Zool. Soc. London, XXIV, 1850, p. 49. 



South of Koh Kut, 17—20 fathoms, mud (Ma). 



Long. 4 mm. 



Distribution: — Singapore, Gulf of Oman (Melvill & Standen). — PhiH|)- 



P 



nes, Borneo. 



Nuculana Belcheri, Hinds. 



(PI. 1, Figs. 18-19). 



Niicula Belcheri, Hinds, Proc. Zool. Soc. London, XI, 1843, p 98. 



— — — Zoology of the voyage of "Sulphur." Mollusca by Hind.s. 1845, p. 63, pi. 18, 



fig. 11. 

 Leda — — Hanley, Monogr. of the fam. Niicu/i'dœ (Sowhiikv, Tlicsaurus Conchyl., Ill), p, 116, 



pi. 2, fig. 53. 

 Lœda — — Reeve, Conchol. icon., XVIII, Lœda, Sp. 23. 



Nuculana — — Smith, Proceed. Malacolog. Soc. London, V, 19(13, p :f95, No. 346. 



The Sound of Koh Chang, 5 fathoms, soft clay. ('/a). 



Long. 10 mm. 



Distribution:— Agulha Bank, Cape of Good Hope (Belcher), oil" Cape 

 Colony and Natal, 34—440 fathoms (Edg. Smith). ' 



The single valve obtained from the Gulf of Siain is not full-grown, therefore, 

 as may be seen in PI. 1, F'ig. 19, the characteristic central keel, which extends from 

 the ventral side towards the umbo, is absent at the posterior end: this agrees 

 entirely with the opinion expressed by Hanley (loc. cit., p. 117) "As the central 

 keel does not extend to the umboes, it is probably wholly absent in Ihe fry." 



' On Siiutli African Marine Mollusca. (Annals of llio Natal Government Museum. Vol. 1, p 1. 1906). 



