Order Protobranchiata. 
Fam. Nuculidae. 
Nucula Cumingi, Hinds. 
Nucula Cumingii, Hinps, Proc. Zool. Soc. London, XI, 1843, p. 97. 
— — — “Zoology of the Voyage of “Sulphur.” Mollusca by Hinps, 1845, p. 62, pl. 18, 
fig. 1. 
-— — — Haney, Monograph of the fam. Nuculidz. (Sowersy, Thesaurus Conchylio- 
rum III.) p. 157, pl. IV, fig. 117. 
— _— — REEVE, Conchol. icon., XVIII, Nucula, Sp. 5. 
The Gulf of Rayong and Cape Liant. Common around Koh Kut and Koh 
Kahdat, 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, = Haney, Monogr. of the fam. Nuculide (Sowenrsy, Thesaurus Conchyl., III.) 
p. 160, pl. V, fig. 153. 
— ~_ — REEVE, Conchol. icon. XVIII. Nucula. Sp. 36. 
= Epe. Smirn, Ann. and Magaz. Nat. Hist., 7. Ser., XVIII, 1906, p. 252. 
West of Koh Chuen, soft clay and mud. (*/2).2. The Sound of Koh Chang, 
3—5 fathoms, soft clay (many specimens). The coast of Lem Ngob, low tide ('/2). 
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. Apams). 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 Ene. 
SmitTH (loc. cit.) to occur in his “single shell”, which measured 15 mm. in ijength, 
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. 
1 In the list of localities “sand,” “mud”, “stones,” etc. stand for “sandy bottom,” “muddy bot- 
tom,” “stony bottom,” ete. 
‘ The number in parenthesis indicate throughout the number of specimens collected. 
