igig.] N. Annandale : Bombay Streams Fauna. ill 



bottom of the pool. Except algae, which are scantily represen- 

 ted, there is no living vegetation. 



The fauna of this pool is chiefl}' a bottom fauna. The bare 

 rock of the sides is covered for considerable areas by the hard 

 black encrusting sponge Corvospoiigilla ultima var. spinosa and by 

 the much softer and rather thinner green species Spongilla pervi- 

 ridis and 5. sumairensis var. rivularis. The Polyzoa Plmnatella 

 javanica and P. emarginata occur sparingly on the cleaner parts of 

 the rocky basin and also on the lower surface of loose stones. In 

 the mud and dead vegetable matter a small white dipterous larva 

 of the family Chironomidae is abundant, while in the more gra- 

 velly spots thick-shelled Unionids {Parreyssia corrugata and P. 

 cylindrica, sp. nov.) are not uncommon. For some inches above 

 the bottom Entomostraca, chiefly Copepods and Daphnids, are 

 abundant and with them occur the larvae and pupae of the Core- 

 thrine Culicid Chaoborus manillensis.^ None of these arthropods 

 commonly rise to the surface, on which the only zooplancton 

 taken in my nets consisted of the statoblasts of Plumatella. Sur- 

 face-haunting fish such as Barilius bendelesis are scarce in the 

 pool, but bottom-haunting forms, notably Discognathus lamta and 

 Gobius bombayensis, aie numerous ; a large proportion of the fish 

 bore the glochidia of Unionidae on their fins at the time of my 

 visit. Small prawns of the genera Caridina and Palaemon are not 

 uncommon, and the crab Paratelphusa (Barytelphusa) jacquemonti 

 burrows in the mud at shallow points near the shore.' 



The facts known about the life-history of Limnocnida are as 

 follows : — they are taken mainly from the papers referred to in a 

 footnote below,^ 



L. indica has been found only in the smaller streams of the 

 upper Kistna river-system, and only in pools situated as described 

 above. It has been observed only in the months of April and 

 May; in places where it is abundant in these months it has been 

 proved to be completely absent in February, March and October, 



^ Both larva and pupa of this fly are modified in correlation with life near 

 the bottom instead of at the surface, the larva in its very small air-sacs, the 

 pupa in several structures, particularly in its balloon like breathing trumpets, 

 which are sufficiently bouyant to keep it in an upright position but not to raise it 

 to the surface. See Baini Prashad, Rec. Ind. Mtis., XV, pp. 154-156 (1918). 



2 I may refer briefly to two small but remarkable Orthopterous insects 

 common at the edge of the pool, viz. Sceliynena harpago (Serv.) and Pavanemo- 

 hiiis pictus, Sauss. The former is an Acridiid grasshopper of the subfamily 

 Acrydiinae (or Tettiginae) and is amphibious in habits, flymg, diving and swim- 

 ming with equal ease. I hope on some future occasion to discuss the peculiar 

 modification of its hind legs by means of which it can cling to rocks under water. 

 The Paranemobiits is a brachypterous, long-legged cricket which runs, as often 

 sideways as forwards, with great agility on the shady sides of dry rocks at the 

 edge of water. It is widely distributed in India (Kashmir to South India) and is 

 always found in this position I have to thank AI. L. Chopard for this identification. 



^ See Annandale, "A Preliminary Description of a Freshwater Medusa from 

 the Bombay Presidency," Rec. hid. Miis., VII, p. 253 (.1912) : Gravely &: Aghar- 

 kar, "Notes on the Habits and Distribution of Limnocnida indica,'' Rec. Ind. 

 Mus., \T1, p. 399 (1912); Agharkar, "Further Notes on the Habits and 

 Distribution of I imnocnida indica," Rec. Ind. Mus., IX, p. 247. 



