1919-] N. Annandale : Bombay Streams Fauna. 121 lives on the surface of water, and as a rule, though not invariably, of still water, in the structure of its feet, more particularly of those of the two hinder pairs of legs. On these feet there is in Gerris a pair of slender, almost bristle-like claws, which are situated at the tip of the limb; some distance in front of them, on the lower surface, there is a large bristle, but there is no definite empodium and the whole structure is degenerate. In Onychotrechus the claws are real claws, of a horny consistency, curved, towards the tips, sharply pointed and flattened from side to side ; they are separated from the extremity of the limb Vjy several strong bristles and small processes perhaps of a sensory nature; similar processes also occur just behind the claws, and between them protrudes a coiled band-like empodium. These structures deserve a more detailed examination, I refer to them here merelj'' to indicate that the foot is modified in this genus to enable it to cling to slippery surfaces, while in Gerris,^ which apparently does not use the claws of its hinder legs at all, they are degenerate. There is less difference between the anterior feet of the two genera, both of which probably use them for grasping prey, but even in these feet the claws of Onychotrechus are much stronger and larger than those of Gerris. These facts are illus-trated in figures 8 and 9 on plate III, drawn on the same scale from insects of approximately the same size. Oligochaeta. — Small white worms of the family Naiadae are abundant in damp algae on the cliffs. The fauna of these cliffs, where they are wet with the spray of waterfalls, includes, therefore, highly modified forms among both the MoUusca and the insects. The latter are still imperfectly known, but there is every reason to think that a proper entomo-logical investigation of the waterfalls would have great biological interest. IV. Some Frogs from Streams in the Bombay Presidency. Only three species of frogs were found at the edge of the streams investigated at Medha and Khandalla. They are Rana cyanophlyctis, an undescribed race of R. Umnocharis for which I propose the subspecific name syhadrensis, and an undescribed species of Ixalus, which I have called /. hombayensis. Both new race and new species are abundant in the Bombay Ghats. The Ixalus has been found in the North Canara, Satara and Poona districts, the race of R. Umnocharis in the two latter and also in the Nasik district; neither form is known to occur at altitudes below 2,000 or above 4,000 feet. ^ I have seen a species of Gerris clinging to rocks at the edge of the Bhavani river by means of its anterior claws. It could not, however, run about on the sHppery surface.
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