TQI5-] Fauna of the Chilka Lake : Coelenterates. 91 



(4) There are twelve vertical rows of solid tubercles on the column. 



(5) The tentacles are normally 12 in number , but extra subsidiary tentacles 



are sometimes produced asymmetrically; both the normal and the 

 subsidiary tentacles are (even when fully expanded) stout, blunt and 

 hardly longer than the longer diameter of the disk. 



(6) The mouth is relatively wide. 



(7) The stomodaeum is spacious, its sulco-sulcular axis occupying nearly one 



half of the diameter of the column. 



(8) The muscle-banners are small, though not so small as in some forms, and 



separated from the walls of the stomodaeum. 



(9) There are no incomplete mesenteries. 



(10) The parietal muscles are feebly developed and accompanied merely by 

 somewhat indistinct projections of the mesogloea. 



Types. No. Z.H.V. 6032/7, Ind. Mus. 



This species has been found as yet only in the Chilka Lake, in the main area of 

 which it is abundant at all seasons except the end of the rains; it is also found, 

 much more sparingly, in the muddy parts of the outer channel. It is commonest in 

 from 6 to 12 feet of water and has been found throughout the range of salinities 

 occurring in the lake. 



Halianthus limnicola is gregarious, and was usually taken on a muddy bottom 

 in which there was a fairly large admixture of dead Iyamellibranch shells. It is 

 very active and not at all shy. When removed from the water or otherwise 

 disturbed it retracts its tentacles instantaneously but extrudes them again the 

 moment that it is comfortable. In a vessel half filled with mud and shells and 

 half with lake- water it begins to burrow almost immediately. This it prefers to do 

 among shells, among which it progresses in an almost horizontal direction, lying 

 prone and dragging itself along with fair rapidity by means of its tentacles. Their 

 movements are accompanied and assisted by rhythmical longitudinal expansions and 

 contractions of the column. No rhythmical transverse contractions of the column 

 were observed, but constrictions often appeared suddenly at different points. The 

 animal has a strange habit of alternately retracting and extruding the proximal 

 part of the physa. No attempt was made to form an external sheath or cuticle, the 

 transparent wall of the column remaining remarkably clean. If left to itself the 

 anemone sometimes formed a vertical burrow, in which, however, it never remained 

 for very long. The muscular nature of the physa would suggest that it is employed 

 in making burrows of the kind, but the process was not observed. 



Although numerous individuals of the species were obtained in most hauls of our 

 nets on suitable ground throughout the greater part of the year (even in July, when 

 the rains were established, and in September, when the water had become fresh), yet 

 in November it was found to be very scarce and only a few specimens were obtained. 

 These were, moreover, in a quiescent condition, exhibiting none of the normal 

 muscular activity, and were so contracted and shrivelled that they could not at first 



