1915-] Fauna of the Chilka Lake : Coelenterates. 109 



The colonies are evidently young or dwarfed. Only one bears fully developed 

 gonosomes and even in this colony the basal crust is still imperfectly developed and 

 remains at many points openly reticulate. In one colony it is still in the primitive 

 condition of a branching and anastomosing rhizome bearing upright hydranths at 

 intervals. The largest shell to which a colony was attached was only 23 mm. long. 



The largest hydranths are not more than 2 mm. long and the majority are much 

 shorter. The number of tentacles is variable, but I have not seen more than 14. 

 Their nematocysts are very small. Even when fully expanded the tips are blunt. 



There are no true dactylozooids, but young gonophores were at first sight mis- 

 taken for them. These individuals have a large central cavity at the base, which is 

 somewhat inflated. The region on which the gonosomes are borne is elongated and 

 slender. Its tip is blunt and not at all capitulate. In this region the structure 

 forms a solid finger-shaped mass. Brownish granules occur abundantly in its inter- 

 nal cells. Bach female gonosome bears three ova. Except in being a little more 

 inflated at the base, the whole gonophore, in mounted specimens rendered trans- 

 parent, somewhat resembles the larger spines but may be distinguished therefrom, in 

 the absence of gonosomes, by its basal cavity and by the absence of a thickened 

 chitinous external coat. The gonophores are shorter than the largest hydranths. 



Clavactinia gallensis was originally taken in Galle Bay on the west coast of 

 Ceylon in two fathoms. Our specimens were found close inshore in not more than 

 two feet of water at Satpara in the outer channel of the Chilka Lake. 



The former specimens were attached to shells of Eburna and Neritina ; Miss 

 Thornely does not say whether these shells were inhabited. Ours were in most 

 instances on shells of Potamides ftuviatilis, and in one on a shell of Nassa labecula. 

 In both cases small hermit-crabs {Diogenes avarus, Heller) were living in the shells, 

 both species of which are abundant at Satpara. The hydroid was present on a small 

 proportion only of the shells collected, though many had been appropriated by 

 hermit-crabs. Our specimens were taken in March, in water practically as salt as 

 that of the upper part of the Bay of Bengal at the same season. It is probable, in 

 view of the immature condition of most of the colonies in March, that the planulae 

 are brought in by the tide in the season of salt water and that the species does 

 not survive the irruption of fresh water that takes place later in the year. 



A minute Campanularian hydroid accompanied Clavactinia on one shell, but the 

 specimen was unfortunately too imperfect for even partial identification. 



Family CORYNIDAE. 



Genus Dicyclocoryne, nov. 



This genus may be defined as consisting of Corynidae in which the tentacles of 

 the hydranth are all capitate and are disposed in two quite distinct circles. The 

 gonosomes, which are borne on the proximal part of the hydranths, are free medusae 

 and have, when liberated, four short, stout capitate tentacles, one at the end of each 

 radial canal, but no ectodermal ocelli. The manubrium, at the same stage, is short, 



