VIII —THE 

 AT PORT 



FAUNA OF BRACKISH PONDS 

 CANNING, I.OWER BENGAL. 



Part IV. — Hydrozoa. 



By N. AnnandaIvE, D.Sc, Officiating Superintendent, Indian 



Museum. 



Only one species of Hydrozoon, Irene ceylonensis , occurs at 

 present in the ponds themselves, but two others have been found 

 in one of the small pits close to the embankment of the river, 

 and might easily be carried into the ponds by a flood. As the 

 smaller pits dry up completely before the end of winter, the pres- 

 ence in them of these hydroids is probably accidental, coming 

 about only when the embankment is broken and water enters from 

 the estuary, bringing with it eggs, larvae or medusse. Considering 

 the three species found in brackish water at Port Canning together, 

 Irene ceylonensis is the only representative of the Calyptoblastea, 

 the two from the pit being both Gymnoblastic ; of these latter, one 

 is an undescribed species of Syncoryne or possibly of a new genus, 

 while the other must be regarded at present as identical with the 

 European Bimeria vestita, from which, however, further research 

 may ultimately prove it specifically distinct. 



Syncoryne filamentata, sp. nov. 



Fig. I. — Trophosome of S. filanientata, x 21. Hydranth and free filament (the 

 latter in optical section), n = nematocyst : g ^gonosome -. h = hydrorhiza. 



Trophosome — 



Colony glistening white in colour. Hydrorhiza branches spar- 

 ingly, does not anastomose, gives rise at intervals to single upright 

 polyps, and is produced at the extremities of the ultimate branches 

 into long, free filaments, the distal ends of which are often slightly 



