1921.] Fauna of the Chilka Lake : Amphipoda. 533 



proportions of the different joints can be readily seen. The tufts of setae on the 

 second joint of the peduncle of antennae 1 towards its extremity seem to be a 

 characteristic feature and may be more developed than is shown in the figure. 



The upper lip (fig. 4c) is regularly rounded and bears a few minute setae. In 

 the mandible (fig. 4a) the molar tubercle is prominent and projecting, the cutting 

 edge and spine row of the normal character, the palp has the first joint short, the 

 next two joints subequal, bearing few setae except the distinct tuft at the end of 

 the third joint. The first maxilla (fig. 4/) differs considerably from the generic 

 description given by Stebbing in having the inner lobe broad and well developed 

 and fringed with about 12 plumose setae. The second maxilla (fig. 4g) has the 

 two lobes subequal, both with apical setae and the inner one with a few setae on 

 its inner margin. The maxilliped (fig. 4h) has the inner lobe large with three 

 stout spinules and a number of plumose setae, the outer lobe reaches only about 

 half-way along the carpus and has its inner margin provided with numerous short 

 setae, none of which are developed into spine-teeth. 



In the first gnathopod (fig. 4k) the merus is produced posteriorly into a 

 slight rounded lobe and appears to be covered with very minute setae, the rest of 

 the appendage seems to be normal, having the characters already mentioned in 

 the specific description. 



The second gnathopod differs considerably from the first both in size and in 

 structure and is rather different from the gnathopods of other species of the genus. 

 The general character will be best learnt from the figure 4I; in larger specimens 

 the propod may be somewhat larger and the swelling on the inner margin of the 

 finger more pronounced. 



The peraeopods aie fully shown in the figures (figs. 4m, n, o, p) and do not 

 call for further detailed description. 



The branchiae (fig. 4m) are all somewhat large in size, rectangular at the 

 base and narrowing a little towards the extremity. 



In the first uropod (fig. 4a) the peduncle is much longer than the rami which 

 are subequal; in the second (fig. 47) the peduncle is only slightly longer than the 

 rami; in both there are numerous spinules on the upper surface of the peduncle and 

 the rami. The third uropods appear to vary in length in different specimens being 

 sometimes as much as one- third of the total length of the body. In figure 4s they are 

 shown in side view as attached to the animal, when viewed from above they appear 

 somewhat broader. The telson (fig. 4t) is cleft to the base, each lobe narrowing 

 posteriorly, the inner margin being nearly straight except towards the extremity, 

 the outer strongly convex. A long spinule arises near the extremity of each lobe 

 and on its inner side there are three minute setae; from the upper surface of each 

 lobe towards the extremity arise two delicate sensory plumed setae. 



In the large inner lobe of the first maxilla and in the gnathopods this species 

 differs considerably from the species of Niphargus hitherto described. I have, 

 however, specimens sent to me by Professor C. F. Baker from springs in the 

 Philippine Islands which closely approach the Chilka I^ake specimens in these 



