Order Protobranchiata. 

 Farn. Nuculidae. 



Nucula Cumingi, Hinds. 



Nucula Ciimingii, Hinds, Proc. Zool. Soc. London, XI, 1843, p. 97. 



— — — Zoology of the Voyage of -'Sulphur." Mollusca by Hinds, 184.'), p. 62, pi. 18, 



fig. 1. 



— — — Hanley, Monograph of the fani. Nuculidæ. (Sowerby, Thesaurus Conchylio- 



rum III.) p. 157, pi. IV, fig. 117. 



— — — Reeve, Conchol. icon., XVIII, Nucula, Sp. 5. 



The Gulf of Rayong and Cape Liant. Common around Koh Kul and Koh 

 Kalidat, 4—30 fathoms, sand, mud and shells. ' 



Long. 4 — 12 mm. 



Distribution: — Singapore, Strait of Malacca, Philippines, New Guinea, Strait 

 of Macassar. 



Nucula Layardi, A. Ad. 



Nucula Layardii, A.Adams, Proc. Zool. Soc. London, XXIV, 1856, p. 51. 



— Layardi, — Hanley, Monogr. of the fani. Nuculidæ (Sowerby, Thesaurus Conchy!., III.) 



p. 160, pi. V, fig. 153. 



— — — Reeve, Conchol. icon. XVIII. Nucula. Sp. 36. 



— - — Edg. Smith, Ann. and Magaz. Nat. Hist., 7. .Ser., XVIII, 1906, p. 252. 



West of Koh Chuen, soft clay and mud. (^2).^ The Sound of Koh Chang, 

 3—5 fathoms, soft clay (many specimens). The coast of Lern Ngob, low tide ('(3). 



Long. 4 — 10 mm. 



Distribution:— Ceylon, Bombay, Karachi, Mekran Coast, Gulf of Oman, 

 Persian Gulf. 



Reeve (loc. cit.) is correct in saying that the present species is much more 

 nearly allied to N. Cumingi than to N. convexa (as stated by A. Adams). The out- 

 line of N. Layardi corresponds almost completely with that of N. Cumingi. The 

 number of the hinge-teeth ("six in front and nineteen behind") stated by Edg. 

 Smith (loc. cit.) to occur in his "single shell", which measured 15 mm. in length, 

 is not always constant, more or fewer teeth frequently occurring. Undoubtedly the 

 age, size and development of the individual also have a share in regard to this 

 feature. 



' In the list of localities "sand," "mud", "stones," etc. stand for "sandy bottom," "muddy bot- 

 tom." "stony bottom," etc. 



' Tlic numlier in parenthesis indicate throughout the number of specimens collected. 



