156 IV 



•sound — if so my efforts would have been almost lost. Adm. Richelieu placed a rather 

 large boat to my disposition, with which I could go out for several days, and then better 

 places were found with the rich and varied fauna, one might expect in tropical waters. 

 Such places were especially lioh Kahdat, a little island a few miles S. of Koh Chang, 

 and the small islands of Koh Chuen, Koh Mesan, and Koh Kram farther North. 



All round Koh Chang the bottom was the horrible mud , which filled the dredge 

 instantly, and gave almost nothing but dead bivalve shells. There was, however, a small 

 good place on the western coast of Koh Chang, the little island of Koh Lorn, consisting 

 only of some rocks with a few trees. Here was a very interesting fauna to be found above 

 low-water mark, especially large Chitons and several forms of Cirripedia among the immense 

 numbers of oysters forming here (and everywhere on the rocks of the shores) a broad 

 white border between high and low water mark. Under the smaller stones on the shore 

 were found large numbers of a black Synaptide and several other animals. 



At Koh Kahdat there was a beautiful sand-bottom with corals and the rich animal 

 life connected with them. Just outside the reef there was a rich dredging ground, but 

 only a very narrow belt, scarcely a hundred meters broad. At the depth of about 5 fathoms 

 the well-known mud began; when we came there with the dredge, it was instantly filled 

 with mud — and on the other side the corals tore the net of the dredge. The boat was 

 by no means easily steered, and it was too big to be rowed — thus the difficulties con- 

 nected with dredging here were very great. But when we happened to get over all the 

 difficulties, the hauls were mostly very rich. 



Even better was the place at the islands of Koh Mesan, Koh Chuen, and Koh Kram. 

 The bottom was sand with stones and corals out to the greatest depths found here, c. 30 

 fathoms. As the Madreporarian Corals are found only out to 3 — 4 fathoms in these 

 waters, there were excellent conditions for dredging outside the reefs, and very rich col- 

 lections were made here. It was most interesting to compare the fauna of the sound 

 between Koh Mesan and the mainland (Cap Liant) with that of the sound at Koh Chang, 

 the fauna being very rich and varied here in the clear water. — If the station had been 

 here, the collections would have been even much richer; but here was no water to be 

 had, and no people lived in the neigbourhood. A stay of about a week here with the boat 

 was only possible by the Admiral ordering supplies of water and food for us fromRayong. — 

 Among the collections from this place I may mention some bottom-samples, which were 

 extremely rich in small Crustaceans (Cumacea, Ostracoda etc.). 



Several times the Admiral allowed me to go with H. S. M. S. «Chamroen» to dredge, 

 and thus I have been able to investigate the fauna of a large part of the east side of the 

 Siam-Gulf, from Koh Kong to Koh si Chang. As the depth is very uniform in the Gulf, 

 and the bottom is mud everwhere, I have not tried to go far out from the coast, supposing 



