1921.J Manipur Molluscs. 537 



Pectinatella and probably P. burmanica, but still in a stage in 

 which the individual colonies had not become embedded in a 

 common jelly. There were no statoblasts in these colonies. Small 

 Oligochaete worms were abundant among the weeds and a larger 

 form with gills on the sides of its posterior region was obtained from 

 mud at the bottom. Leeches of various species were collected, 

 but only one, a GlossosipJionia parasitic on Vivipara oxytropis, was 

 at all common. 



The Crustacea were less well represented than might perhaps 

 have been expected. Small Ostracods were abundant at certain 

 spots among the weeds, but few other Entomostraca were observed. 

 The Decapoda were singularly scarce, the only species collected 

 being a small Palacmon. Crabs were apparently absent, and so 

 also were Atyidae, which might have been expected to abound 

 among the weeds. Aquatic insects were also rather scarce, the 

 commonest being dragonfly larvae of the families Agrionidae and 

 Libellulidae. In the smaller channels among the floating islands 

 large numbers of mosquito larvae (both Culicinae and Anophelinae) 

 were often seen, and larvae of Chaobonts were dredged from the 

 bottom of the lake. Several large species of Dytiscidae were 

 fairly common, but water-beetles generally' were scarce. Although 

 the molluscs were rich in number of individuals, the number of 

 species that occurred actually in the lake was small. Several 

 typically non-lacustrine forms, notably Limnaea acuminata and 

 Indoplanorbis exiistus, were found all over the lake and the only 

 Gastropods that could be regarded as really characteristic were 

 two exceptionally large species of Viviparidae {Vivipara oxytropis 

 and Lecytlioconcha lecylhis), both of which are also paludine. Dead 

 shells of Lamellidens corriamis were picked up at the northern end 

 of the lake, but Unionidae were evidently very scarce. A species of 

 Sphneriiim {S. indicum) was, however, fairly common among the 

 weeds. All heavy -shelled forms were naturally absent. 



Fish were very abundant, but unlike those of the Inle Lake, they 

 were not highly spacializad. Few very small species were 

 seen, but the great majority do not grow more than 5 or 6 inches 

 long. Except eels, indeed, few fish in this lake attain the length 

 of one foot Cat-fish (Siluridae, sen'ni lato) are particularly well 

 represented in our collection. A large proportion of the species of 

 this and other families are provided with highly developed tactile 

 organs, and the enlarged eyes so characteristic of the Inle fish-fauna 

 are not found among them. The general facies of the specimens is 

 that of swamp-fish, and genera peculiar to swamps and similar 

 bodies of water are present. 



Frogs and toads are not abundant, at any rate in ;\Iarch and 

 April, but Rana liinnocharis and Bujo jnelanostictus, two of the 

 most abundant Indian species, were observed on the shores of the 

 lake and the tadpoles of the toad were found in a smah pool of 

 water on one of the islands. We saw no kind of water-tortoise and 

 the local fishermen assured us that they were not acquainted with 

 any. 



