1915] Fiimict of iJic Cliilkd Lake : Crustacea Deeapoda. 207 



Ebalia malefactrix. Scylla serrafa. 



Ocypoda macroceya. Clibanaiius padavensis. 



Gelasimus aimulipes. Clibanariits loiigitarsis. 



Pacliygrapsus pvopiiiqiiiis. CUhaiiarius olivaccits. 



Varuna litteyata. Diogenes avarus. 



Camptandrium sexdentatiim. Urocaris indica. 



Sesanna batavicuni. Periclimenes demani. 



Cardiosoma cam i /ex. Ogyrides striaticaiida. 



Heteropanope indica. Alpheiis malabaricus. 



Leipocteii sordid ii/it in. Penaeiis carinatiis. 



Penaeopsis dobsoni. 



Metasesavma roiisseaiixi, Sesarma qiiadratu in and Nepfiiiuis saiigninoleiitiis , com- 

 mon and characteristic species in the Madras backwaters, are absent from the Chilka 

 Lake. 



It is noteworthy that a considerable number of the species in the above list are 

 known only from Indian backwaters, whereas the majority of those common to the 

 Chilka Lake and the Gangetic delta are wddely distributed forms. Ebalia malefactrix 

 and Ogvrides striaticaiida have also been found in the Cochin backwaters on the south- 

 west coast of India. 



As far as the Decapods are concerned, therefore, the lake fauna shows a much 

 greater resemblance to that of the Madras backwaters than to that of the Gangetic 

 delta, and this fact is also illustrated by other groups of animals. 



Owing to the fact that our survey of the lake fauna was, in the main, restricted 

 to one year, our observations on the periods at which the different species breed are 

 unfortunately very incomplete; but in a few instances the evidence is interesting. 

 On the Indian coasts in February and March females of the great majority of littoral 

 marine Deeapoda are to be found bearing eggs and, inasmuch as the water of the 

 lake is at this period almost at its maximum salinity, it would naturally be supposed 

 that species usually marine, or closel}^ related to marine forms, would breed at this 

 season. In several instances, however, this is certainly not the case. 



Only of five species (all of them forms found in the outer channel, but absent 

 from the main area) were ovigerous females obtained solely in water as salt as that 

 of the Fjaj' of Bengal (sp. gr. i 0265). These are : — 



Dotilla pertinax. Ogyrides striaticaiida. 



Diogenes avarus. Athanas dimorphus. 



Alplieiis malabaricus. 



As far as our observations go, seven species breed in water that is strongh* saline 

 or brackish, but were not found bearing eggs in fresh water. The names of these 

 species are as follows, the specific gravities of the water in which ovigerous females 

 were found being added in brackets: — 



