IÇI5-] 



Fauna of the Chilka Lake : Crustacea Decapoda. 



325 



Lucifer hanseni occurred in shoals in the Chilka Lake and was abundant in the 

 main area at all times of the year, existing in water of specific gravity varying from 

 1 -ooo to 1-0150. In the outer channel it was common in September in fresh water; 

 but was extremely scarce in March when the water was as salt as the Bay of Bengal 

 near the lake (sp. gr. 10265). If the only data available were those obtained in the 

 Chilka Lake, one would suspect that the species preferred a low salinity and that it 

 was only by chance that it came in contact with sea-water. But the species, as will 

 be seen from the records on p. 323, is common in the Bay of Bengal and was on one 

 occasion found in nets fished in mid-water over a sounding of 500 fathoms. I am 



Fig. 37. — Lucifer hanseni, Nobili. 



Fig. 38.— Lucifer reynaudii, M.-Ewd. (Dana). 



a. Last abdominal somite of male, in lateral view, 



b. do. of female, in lateral view. 



c. Outer uropod of male. 



d. Outer uropod of female. 



unable to offer any explanation of the scarcity of the species in the outer channel in 

 March. 



Young post-larval specimens were found on a number of occasions in the fresh- 

 water season, but I am not convinced that the species actually breeds in the lake; 

 the young individuals obtained may have grown from larvae brought into the lake 

 from the sea some months earlier. Specimens from the lake are on the whole 

 decidedly smaller than those obtained in the Bay of Bengal; the largest individuals 

 from the Chilka Lake scarcely reach 8 mm. in length, whereas those from the 'In- 

 vestigator' collections frequently exceed 11 mm. 



Apart from the specimens from the Chilka Lake and from those recorded on 

 p. 323, Lucifer hanseni is known only from the Red Sea. 



