1922.] Luminosity of some animals in the Gangetic Delta, 583 
observed, is due to bacteria which find a suitable medium in 
this fish and with all other suitable conditions in surroundings, 
like the Gangetic Delta, form large colonies on the body of the 
fish and becoming active produce light. thus making the fish 
phosphorescent. 
The 
away the prawns, he found them all glowing, and brought round 
the dish to me for examination. In the case of these prawns 
the gills only were emitting a faint bluish-green light of about 
the same intensity as I had noticed in the case of the Bombay 
n emp 
as the race bengalensis. The specimens that collected in the 
Sunderbans are intermediate to some extent between the two 
it brought back to Calcutta were identified as Beroe sangre 
F6rskal a form widely distributed in the East; Pp arg ha 
the second Ctenophore which was found in the Chilka ’ 
but no specimens of whic 
As a result of their wor 
not show any light when at oe 
swimming plates accompanl 5 ‘ 
; re 
energy-release are, therefore, not connected, as 4 

antamaa 

Jo 


| Herdman’s Ceylon Pearl Fisheries, IV, p. 61 (1905). 
2 Mem. Ind. Mus., V, PP- 117, 118 (1915). Sy A9i6) 
3 The Production of Light by Animals, Pt. IU, p- ; 
