1916.] B.SuUNDARA Raj: Freshwater Fish of Madras. 273 
Ophiocephalus punctatus, Bloch. 
(Pl. xxvii, figs. 17—22). 
Tamil—M aniang koravai (Para korava (Day) is the name of O. 
gachua in Madras). 
Habitat and Habits.—A very common species in ponds, ditches 
and rivers. In the last it is known to occur in brackish water 
when it is said to acquire a purplish colour.! It is a mud-burrow- 
ing fish* and prefers stagnant and muddy to running water.’ It 
is one of the fish Day saw exhumed from the mud of a dried-up 
tank.* 
The breeding habits are very similar to those of O. striatus. 
O. punctatus is monogamous, and breeds twice in the year, about 
January and February and again about July and August ; occa- 
sionally nests are met with at other times.’ At these seasons the 
fish come together in pairs and construct a nest among the rushes 
in the shallows of ponds and rivers. I have never seen the nest 
in water deeper thari a foot and a half, as a rule it is built in water 
only a foot in depth. The nest is the usual roundish clearing 
measuring 8 or ginches in diameter. The nests of O. striatus differ 
in being larger (about 12 to 14 inches in diameter) and are found in 
water at least 2 feet, frequently 3 or 4 feet deep. At the surface 
the nests of both species appear as circular areas of clear water 
with the eggs floating in the centre. Both parents tend the nest; 
while the male keeps a vigorous guard, aggressively protecting the 
spawn from intruders, the female is found in the neighbourhood. 
Eggs.—Oviposition usually takes place at night ; a few thou- 
sand eggs® are deposited by the female in a single night. The 
eggs measure about 1°25 mm. in diameter and are of a pale am- 
ber colour. In size and appearance they are hardly to be distin- 
guished from those of O. strzatus and like the latter contain a large 
oil-globule and float flush with the surface of the water’ (figs. 17 
and 18). 
The rapidity of the embryonic development seems to depend 
on the strength of the sun. On all occasions whenI obtained col- 
lections of eggs they invariably hatched during the night following, 
z.€., on the average in 24 hours after procuring them. ‘This cor- 
roborates the statement of fishermen that the eggs of O. punc- 
tatus usually hatch on the night following that on which they 
are laid. 

1 Day, Fishes of India, p. 308. 
2 Willey, Spol. Zevlan., V, p. 149. 
8 Day, Fishes of India, p. 308; Fauna of Brit. India, \I, p. 365. 
4 Day, Freshwater Fish and Fisheries of India and Burma, p. 28 (1873). 
5 Willey records finding a nest in October, Spol. Zeylan., VII, p. 101 (1911), 
and I have seen nests in the Cooum in December. 
5 Day, Fishes of India, p. 318 (records finding 4702 eggs in a female in 
February ). 
7 Willey, Spol. Zeylan., VII, p. tot. 
3) 
