292 Records of the Indian Museum. EchompeG tls 
Days after hatching. Total length. Principal events. 
12—15 60°75 mm, Posterior end of notochord bends up. 
28 8 to 10 mm. Caudal rays jointed and articulated 
with the basal cartilages. Larvae 
rise to surface to take air. 
37 a 10 mm, Primordia of dorsal and anal rays. 
40 ae LO°25 tO) £3 mam. Rudiments of ventral fins appear. 
Dorsal and anal fins separating 
from caudal. End of larval deve- 
lopment. 
17 mm. 
2 
a a Fry now hide in the mud. 
73 e 25 mm. - 
Characteristic colour of the Larvae.A—On either side of the body 
there is a broad reddish-orange band occupying almost the entire 
height of the myotomes, commencing from the eye on each side, 
and ending behind with a rounded edge at the base of the caudal 
fins. ‘The iris is golden with a red flush; there is a bright golden 
occipital point, and the base of the anal and dorsal fins is black 
along their whole length. This characteristic livery is retained by 
the fry till they reach a length of about 40 mm. (nearly for 3 months 
after hatching) ; after which period the definitive markings begin 
to appear, in the form of 9 dark vertical half-stripes on either side 
descending from the base of the dorsal fin. 
Growth.—From the fifth day after hatching, when the larvee 
begin to feed independently, the daily growth begins to vary. 
Some young O. striatus kept by Dr. Willey in Colombo had an 
average total length of about 35 mm. in February 1908, 45 mm. 
in July 1908, 96 mm. in April 1909; the series last measured con- 
sisted of six individuals ranging from 85 mm. to 115 mm. The 
average measurements of a brood hatched in the central pond of 
the Marine Aquarium, Madras, was as follows :— 
Aprile. ts ts. 7 Matched siromeses: 
Bg LO sl eo iu (eO anChes: 
DaelOIss Pee .. over a foot in length. 
In nature growth is even more rapid and the young under 
favourable conditions begin to breed in about two years. 
Uses.—O. striatus is one of the largest and most valuable food 
fishes of our inland waters. Being an air-breather it is transported 
with ease®; and is admirably adapted for pisciculture. Care, 
however, should be exercised in introducing it into preserved 
waters * as it is very voracious and destructive to fry. The young 
are susceptible to attacks from internal parasites ( ? Schistocepha- 
lus larvee).* 


| Willey, Spol. Zeylan., V, p. 145 (1908); VII, p. 116 (1910). 
2 Day, Rep. Freshwater Fish and Fisheries Ind. and Bur., p. 25 (1873). 
3 Thomas, Rod in India, p. 234 (1897); Willey, Spol. Zeylan., V, p. 146 
(1908). 
4 Willey, Z.c. 
