^8 Records of the Indian Museum. [Vol. XV, 



We cannot consider the parasite to be a simple primitive form be- 

 cause of its structure, particularly the structure and disposition of the 

 suckers, the excretory vessel, the specialised cyst, and the partheno- 

 genetic method of reproduction. 



Systematic position :— Owing to the degenerate nature, and the 

 peculiar reproductive phase of the parasite in question, there is very 

 great difficulty in assigning it to its true position amongst the 

 Cestoda, but the presence of four unarmed suckers, as well as an unarmed 

 rostellum, would suggest affinities with the Taeneoidea (CyclophylHdea). 

 For this peculiar worm we propose the name Ilisha farthenogenetica, 

 n. g., n. sp. 



The generic characters would be as follows : — 



Small parasitic leaf -like worms occurring in cyhndrical cysts. 

 Anteriorly there is a rostellum and four suckers, which latter are 

 arranged symmetrically round the base of the rostellum. All these 

 are unarmed. Sexual organs and genital pores absent. Parthenogenetic 

 development. The young are quite like the adult and find their way out 

 of the parent, and later on repeat the same life-history. 



Of doubtful affinity. 



Habitat. — The mesentery and liver of Hilsa ilisha (Ham. Buch.) 

 from various places in Bengal ; September and October, 1917. 



A very large number of specimens. No. Z.E.V. -y^ in the collec- 

 tion of the Indian Museum. 



Literature cited— 



(1) Benham, W. B. — Platyhelmia, Mesozoa and Nemertini, in 



Lankester's Zoology, Part IV. London, 

 1901. 



(2) Braun, M. — Cestoda in Bronn's Klassen and Ordnungen des 



Their-Reichs. Leipzig, 1879-1893. 



(3) Diesing, K. M. — Systema Helminthmn, Vol. I. Vienna, 1850. 



(4) Hill, T. P. — A contribution to a further knowledge of the 



cystic Cestodes. Proc. Livn. Soc. N. 

 S. W., Sydney, 1894. 



(5) Liihe, M. — Susswasserfauna Deutschlands . II. Parasitische 



Plattwurmer. II. Cestodes. Jena, 1910. 



(6) Villot, F. C. A. — Memoire siir les Cestique des Tenias. Ann. 



des Sci. Nat. (Zool), VI. Paris, 1882. 



