250 Records of the Indian Museum. Vou. Seite 
them contain fresh water excepting a few on the sea-coast in which 
the water is brackish. The rivers Cooum and Adyar, like most 
rivers of the Coromandel coast, are almost dry for several months 
of the year; the season of their chief flow is usually during the 
N. E. monsoon (November and December). When in flood they 
are raging torrents and the water is brick-red owing to the admix- 
ture of a red deposit of light specific gravity: at other times the 
water is clear and collects in pools on the bed. Near the mouth for 
a distance of over two miles from the sea both rivers form extensive 
estuaries, and the embouchures of both are encumbered by natural 
bars. Since the construction of the Buckingham Canal it has been 
found necessary to keep the mouths of both the rivers closed 
throughout the year in order to regulate and confine their spill so 
as to contract the waterway for boat traffic: in the case of the 
Cooum a high level in the estuary is further necessary for sanitary 
purposes, in order to keep submerged its sewage-laden banks and 
shoals. Hence the estuary is not subject to tidal action and the 
percentage of salt is not very variable. A sample of water ob- 
tained from the Cooum estuary in August, when the river was at 
its lowest, had 3°576 per cent of dissolved salts and a specific 
gravity of 1°0164.! 
The Cooum estuary is always highly contaminated with sew- 
age except during the freshets. 
The flora of the ponds and the rivers in Madras is more or 
less the same and consists chiefly of many filamentous and unicel- 
lular algae notably species of Chava and Spirogyra; the former 
abounds in brackish water. A few species of Phanerogams, prin- 
cipally Elodea and Vallisneria, occur; the former is the commonest 
and the most abundant water-weed in Madras, while the latter is 
found in clumps in a few places in the rivers. 
Of the 57 species of fish recorded, one (Panchax parvus) is des- 
cribed as new to science ; in the case of at least three species, wz. 
Catla catla, Doryrhamphus brachyurus and Mastacembelus pancalus, 
the geographical distribution has been extended; in two species, 
Anabas scandens and Macrones vittatus, albinism has been noted 
and for more than a dozen, information regarding breeding habits 
has been furnished. Notes regarding growth and colouration of 
fry are based mainly on observations conducted in aquaria. How- 
ever, I have been able to verify the results of such experiments in 
most cases by obtaining identical stages direct from nature. 
I am indebted to Drs. J. R. Henderson and N. Annandale for 
many references and much help; and to Dr. B. I,. Chaudhuri for 
kindly. confirming my identifications in a few doubtful cases. My 
thanks are due to Mr. H. C. Wilson of the Madras Fisheries for 
permitting me to publish his figures of the eggs and larvae of 
Gobius striatus and for valuable information that he has kindly 
given ine regarding the habits of some of the species. 

! I am indebted to Mr. Ramaswami, B.A., of the Madras Fisheries, for this 
information. 
