342 42 



Heteroplax dentata Slimpson. 



Heteroplax dentata Stimpson, Smithson. Misc. Coll., XI>IX, 94, 1907. 



Koh Kahdat, 5—8 fath., sandy mud; II. 10 and III. 4; 1 J" 1 ?. 2 miles S. 

 of Koh Tulu, 10 fath., sandy mud, shells; II. 9; 3 ?. 



Heteroplax transversa Slimpson. 



Heteroplax transversa Stimpson, Smithson. Misc. Coll., XLIX, 95, 1907. 



Between Koh Kahdat and Koh Kut, 6 fath., sandy clay; I. 9; 1 c? 1 ?. Gulf of 

 Rayong, 7 — 10 fath., sand, mud, shells; II. 8; 1 d*. 2 miles S. of Koh Tulu, 10 

 fath., sandy mud; II. 9; 1 Ç juv. 



Subfamily Rhizoplnæ. 

 Ceratoplax ciliata Stimpson. 



Ceratoplax ciliata Alcock, LXIX, .320, 1900. 



Gulf of Rayong, 7—10 fath., sand, mud, shells; II. 8; Id*. Koh Kahdat, 4—5 

 fath., sand, stones, coral; II. 15 — 18; 1 c?. 



Ceratoplax hispida Alcock. 



Ceratoplax /iispida Alcock, LXIX, 321, 1900. Illus. Zool. Investigator, Crust., pt. X, iil. LXI, fig. 4, 1902. 



Gulf of Rayong, 7 — 10 fath., sand, mud, shells; II. 8; 1 Ç. 2 miles south of 

 Koh Tulu, 10 fath., sandy mud, shells; II. 9; 2 ? (1 ovig.). 



The specimens are all small, about 29 mm. long x 3 9 mm. wide. 



Mertonia lanka Laurie. 



Plate II, fig. 4. 



Mertonia lanka Laurie, Report Ceylon Pearl Oj'ster Fisheries, pt. V, Suppl. Rept No. XL., p. 424, pi. I, 

 fig. 11, 11 a-c, 1906. 



Between Koh Mesan and Cap Liant, 9 fath.; II. 4; 1 Ç ovigerous. Length 39 

 mm.; width 53 mm. 



Second leg similar to the third, but slightly longer, the additional length being 

 in the dactyl. The fourth leg is broader than the second and third, ils merus and 

 dactyl shorter, but its coxa and ischium longer than in those legs. 

 The markings on the wrist and hand resemble large flat squamæ. 



Rhizopa gracilipes Stimpson. 



Rhizopa gracilipes Stimpson, Proc. Acad. Nat. Sei. Phila., X. 95 [41], 1858. cf. Alcock, LXIX. 322, 1900. 



Sound at Koh Chang, 3—5 fath., soft clay bottom; XII. 24—1. 6; 23 c? 30 ? 



(1 ovig., 3 with Rhizocephalids). S. of Koh Bidang, 9 fath., mud, shells; I. 18; 



1 Ç. S. of Koh Mak, 5—6 fath.; II. 17; 3 juv. Off Koh Kut, 6 fath.; I. 26; 1 d". 



