1915O Fauna of the Chilka Lake ; Coelenterates. 105 



The position of the medusa of this species is somewhat enigmatical. Browne 

 placed it in Irene (or Eirene), and Mayer, relying wholly on Browne's description, 

 in Phortis. It seems to me to have affinities with Tima, 1 but does not altogether 

 agree with that genus, although its gonads, when fully adult, reach practically from 

 the base of the manubrium to the edge of the disk ; there are no cirri and no conspicu- 

 ous band of longitudinal muscles on the lower side of the tentacles. I have, how- 

 ever, been able to detect a very thin band of the kind in this position. As the 

 hydroid is merely a dwarfed Campanulina, it seems best to place the species in that 

 genus, in which the adult medusae have not been satisfactorily identified. 



The hydroid 2 forms a minute colony barely visible to the naked eye. It con- 

 sists of a sparsely branching adherent rhizome that gives origin at intervals to single 

 hydrothecae borne on short ringed pedicels about one-seventh as long as the cup. The 

 hydrothecae are nearly cylindrical and can be closed above by an operculum con- 

 sisting of several triangular flaps. The hydranth has about 14 very long slender 

 tentacles with regular rings of stinging-cells and but slightly webbed at the base. 

 The hypostome, which is conical, is small and inconspicuous. 



Medusae from Port Canning in the Gangetic delta exhibited every gradation 

 between Browne's two nominal species (1907 (2), pp. 140, 141). An increase in the 

 number of concretions in the otocysts was regularly correlated with the production 

 of extra tentacle-bulbs that did not reach their full development. Both changes 

 were apparently due to degeneration and took place towards the end of the season 

 at which the medusa flourished (December to March), when the water of the pools 

 in which it was found began to grow hot. 



The hydroid was found on the leaves and stems of water-plants at Port Canning 

 in November, December and January. Both medusa and hydroid have now dis- 

 appeared from the pools. 



The medusa is common off the coast of Burma in winter. It was taken in the 

 Gulf of Manaar and Palk Straits in March and July. At Port Canning, the only 

 locality at which the hydroid has been found, both generations flourished for a time 

 in brackish water. Neither was, however, found in the main area of the Chilka Lake 

 and the species is represented in our collection by a single medusa that was taken 

 in the outer channel, in salt water, in March. 



In the second of my papers published in 1907 I dealt with the feeding habits of 

 the medusa, which sucks out the contents of filamentous algae as well as swallowing 

 small Gastropod molluscs and finally ejecting their shells. It is the hardiest medusa 

 with which I am acquainted and will survive for some hours corked up, several indi- 

 viduals together, in a small tube carried in the waistcoat pocket. 



. ' For definitions of the different medusoid genera here referred to see Mayer's Medusae of the 

 World II, pp. 307, 311, 314. 



a All my specimens of this hydroid are now in the hands of Dr. Ritchie of the Royal Scottish 

 Museum, who will, I hope, give a full description in his account of the shallow- water hydroids of the 

 Indian Seas. Dr. Ritchie will describe shortly in the Records of the Indian Museum a minute and very 

 interesting hydroid from brackish water in the Gangetic delta. 



