igoy.] Records of the I ndian Museum. 39 



At the beginning of December they were not sexually mature ; 

 at Christmas G. C. Chatterjee found speoimens in which he could 

 detect ova ; at the beginning of January onh^ spent individuals^ 

 dead or moribund, could be procured, their umbrellas persisting 

 for some da^^s after the sense-organs and gonads had disappeared. 

 At the last date, however, specimens of the Hydroid were taken 

 in which the gonophores still bore gonosomes half developed. A 

 second brood was sexually mature in March. I have already de- 

 scribed the Hydrozoon of this species briefly, and hope to do so 

 more fuU}^ in the present series ; the Medusa was described by 

 Browne from the seas of Ceylon. Both Medusa and Hydroid 

 show a power of resisting unfavourable conditions (especially 

 lack of aeration of the water) remarkable in their order and 

 contrasting markedly with the feeble nature of this power displayed 

 by Hydra in India. A large number of the Medusae lived for 

 over 48 hours in a small corked tube of water in which a single 

 Hydra would hardly have survived for an hour. 



In the smaller ponds near the embankment I found two other 

 Hydrozoa, one of which appears to be specifically identical with the 

 European Bimeria vestita, which has recently been recorded from 

 South America (6), while the other represents a new species of 

 Syncoryne. None of these genera have representatives in fresh 

 water, but all. belong to the littoral zone. 



Mollusca. — Stoliczka (7) stated that most of the Mollusca in the 

 ponds belonged to marine types ; but this is putting the matter a little 

 too strongly, for many of the species belong to characteristic lacus- 

 trine genera, while others are common in estuaries. Nevill (8) des- 

 cribes Hydrobia {Bclgra^tdia) miliacea as occurring in " brackish- water 

 ponds (at Port Canning), associated with Valvata {}) microscopica , 

 Nev., new species of Blythinia, Martesia, Teredo (?), Pharella, 

 Theora, Stenothyra blanfordiana, etc." Preston (9) has recently 

 described five new species of Corbula and one of Bithinella from my 

 own collection, and I have also found an Ampullaria and two 

 species of Melania. Although several species of Onchidhmi are 

 not uncommon on the banks of the Matla, while at least one occurs 

 in ditches and pools of brackish water as far inland as Calcutta, 

 I have not found any in the Port Canning ponds. 



Nematode. — Dr. von lyinstow (10) has described a new Nematode 

 of the genus Oncholaimus from the ponds. All previously known 

 species of this genus are marine. 



Rotifers and Gastrotricha. — The Rotifers have been submitted 

 to Prof, von Daday. In January, 1906, I took among filamentous 

 algse from the ponds a representative of the Gastrotricha which 

 agrees very closely with Zelinka's (11) figure and description of Chce- 

 tonotus schulizei, which I have also seen in a similar situation in 

 freshwater tanks in Calcutta and Chota Nagpur. 



A nnelid. — The only Annelid seen was a small Poh^chaete which 

 burrows in the mud in great numbers. 



Polyzoa. — -Stoliczka (7) took the Cheilo.stome Membranipora 

 bengalensis in the Port Canning ponds thirty-eight years ago, but 



