IX. NOTES FROM THE BENGAL FISHERIES 

 LABORATORY. 



No. 4. CESTODE PARASITES OF HILSA, HILSA ILISHA 

 (Ham. Buch.). 



By T. Southwell, A.R.C.Sc. [Lond.), F.Z.S., Director of Fisheries, 

 Bengal and Bihar and Orissa ; Honorary Assistant, Indian Museum, 

 Calcutfq,, and Baini Prashad, M.Sc., Superintendent of Fisheries, 



(Plates IV, V.) 



CONTENTS, Page. 



(1) The anatomy and life-history of Rhyndiobothrius ilisha, n. sp., from the intes- 



tine of a shark, Carcharinus gangeticus (Mlill. and Henle) ... ... 77 



(2) A note on the cysts of Syndesmohotlwiumfilicolle, Linton, parasitic in the lateral 



muscles of Hilsa ... ... ... ... ... 82 



(3) A description of a Cestode parasite of doubtful systematic position, from the 



mesentery and liver of Hilsa. ... ... ... ... 83 



I. THE ANATOMY AND LIFE-HISTORY OF BHYNCHOBOTH- 

 RIUS ILISHA, N. SP., FROM THE INTESTINE OF CARCHA- 

 ■ RINUS GANGETICUS (Mull, and Henle).i 



During September and October, 1917 observations were made by 

 us in the Pusser river, district Khuhia, on the habits of Hilsa, Hilsa 

 ilisha (Ham. Buch.). This anadromous fish ascends the Bengal rivers, 

 during the rains, for the purpose of breeding. Two methods of catching 

 the fish are practised by the Bengal fishermen : — 



(1) Small canoes drift down stream, broadside on, trailing behind 

 them a shangla jal. This is a small purse-like net which can be mani- 

 pulated easily by one man. The moment a Hilsa is caught, the mouth 

 of the net is closed, the net is hauled aboard, the fish removed, and the 

 net cast over again. By this method it is very rare for more than 

 one fish to be caught at a time. 



(2) A large gill-net, often measuring 300 feet in length, is shot by 

 one, or between two, boats, and allowed to drift downstream for perhaps 

 two miles or so. It is then hauled. The catch varies between two 

 or three fishes and two hundred. 



In both cases, the boats return to the starting point, picking their 

 way close to the bank of the river, aided by the wind, which fills a big 

 sail of fantastic sha])e and colour. In both the above methods of 

 fishing the entry of a fish into the net is most easily detected. Whilst 

 working with the gill-net, we frequently noticed that fish entered the 

 net, but somehow escaped. On hauling the net it was in every case 

 found to be torn. The fishermen assured us that the damage had been 



^ Carcharius gangeticus (Miill. and Henle) in Day's Fishes in the "' Fauna of British 

 fnclia," 



