350 Records of the Indian Museum. VoL. VEG 
this area was composed, in the main, of large quantities of 
Coscinodiscus and Thallasiosiva. In this respect it resembled the 
flora of the waters off Hinzé Basin, some 25 miles further to the 
north: but I am unable to state whether these areas were con- 
fluent as no observations were made in intermediate waters. The 
flora of Hinze Basin itself agreed with that of area III and the 
estuary of Tavoy River. 
Area II extends from the south point of the Middle Moscos 
South Island to the north of the South Moscos group and then 
splits into two; one band passes down on the west side of the 
Islands, but the main area is continued to the south, in a 
gradually decreasing band, as far as the coast. In this area the 
tow-nettings were extremely large and of a dark green colour and 
consisted very largely of a thread-like alga of the genus Tvicho- 
desmium ; there were also present, in fairly large numbers, several 
species of the genus Ceratium, principally C. tripos, which occurred 
not only as single individuals but also in the chain form. 
Area III extends in a band from the east of the South 
Moscos Islands down to the entrance to Tavoy River, where it 
becomes continuous with the estuarine plankton. Here again the 
tow-nettings were very copious and of a dark green colour. 
Diatoms were exceedingly abundant, the commonest forms being 
Rhizosolenia and Chaetoceras. 
Area IV extends over the whole of the region lying to the 
west of the 20-fathom line. The tow-nettings were of a pale 
pink colour, thereby being in marked contrast to those obtained 
from the two preceding areas. In some respects the plankton here 
was very similar to that of area II in that it contained quan- 
tities of the alga Trichodesmium, but it differed very materially 
in the large number of Radiolaria that were present. As I have 
already mentioned, its eastern boundary corresponds fairly closely 
with the 20-fathom line, and it is possible that we are in reality 
dealing here with a continuation of area II, the differences being 
due solely to the increased depth of the water; butas, in addition 
to the differences above mentioned, it was found that there were 
certain differences in the Copepod fauna present in these two areas 
I have preferred to keep them separate. 
One cannot help being struck by the matiner in which these 
areas are arranged, in roughly parallel bands running approxi- 
mately from north north-west to south south-east Along this 
part of the coast, the main trend of the ebb and flood tides is in 
this same direction, but it does not appear to me to be probable 
that tide alone could cause such a definite banded arrangement, 
and a much more likely explanation would be that we are here 
dealing with a slow though definite current of water moving 
down the coast from the north and carrying the plankton 
with it, and this view receives further support from a study of the 
physical conditions of the coast-line, where we see that the sand- 
banks at the mouth of Hinzé Basin and in Maungmagan Bay 
have a well-marked southerly trend, and at the south end of the 
