376 TELEOSTEI. I'HYSOSTOM I. 



470. (ll.) Clupea ilisha. (Fig. 115.) 



Clupanodon ilisha, Ham. Buck. Fish. Ganyes, pp. 243, 382, pi. 19, 



fig. 73. 



Clupea ilisha, Day, Fish. India, p. 040, pi. clxii, fig. 3. 

 " Sable fish " and " Ililsa " of Europeans ; Palasah, Tel. ; Pitlla, Sind ; 

 Oolum, Tamil ; Nya-tha-louk, Burmese ; Hilsa, Beng. ; Ilisha, Ooriah. 



D. 18-19. P. 15. V. 9. A. 19-22. C. 19. L. 1. 46-49. L. tr. 17-19. 



Length of head 4| to 4|, height of body 3| to 3| in the total 

 length. Eyes situated some distance before the middle of the length 

 of the head, 1 to 1 g diam. from end of snout, and 1| apart. The pos- 

 terior extremity of the maxilla reaches to below the middle or even 



Fig. 115. Clupea ilisha. 



hind edge of the orbit ; lower jaw not projecting beyond the upper. 

 Width of opercle equals about two thirds its height. Fins ventral 

 inserted beneath the anterior halt" of the dorsal. Caudal peduncle 

 as deep as long. 'Grill-rakers numerous and as long as the eye. 

 Scales in regular rows ; 16 to 17 scutes before and 14 to 15 behind 

 the insertion of the ventral fin. Colour silvery, shot with gold 

 and purple ; no spots in the adult, but a row of them along the 

 upper third of the body in the immature, the most distinct of which 

 is behind the upper third of the opercle. 



C. ilisha swarms up all the larger rivers of India and Burma, 

 generally as soon as the mousoon commences ; but the rapidity af 

 the current affects the time of migration. Amongst such rivers as 

 I have examined, the following appear to be the periods when these 

 fish commonly ascend. In the Cauvery and Coleroon they appear 

 about the first or second week of June, and continue for the suc- 

 ceeding four months, but in smaller quantities. In the Kistua, 

 which is very rapid, a few fish arrive at the end of September, 

 when the strength of the current is subsiding ; but it is in the middle 

 of October and in the two following months that the main body 

 ascends. In the neighbouring river, the Godavari, which has a less 

 rapid current, the fish ascend earlier, being most numerous from 

 July to September. In the Hooghly they continue their ascent 

 throughout the south-west monsoon to nearly the end of the year. 



