224 G. M. Giles — Notes on the Amphipoda of Indian Waters. [No. 3, 



ing the eyes and antennnles projecting forwards much beyond that 

 giving support to the antennae. In length, it barely equals the first two 

 thoracic segments together. 



The two pairs of eyes are of fair size and are placed close to each 

 other on the produced upper part of the cephalon, the outer pair being 

 situated a little behind as well as below the inner. 



The thorax consists of seven distinct segments increasing gradually 

 in length from before backwards, the last being the longest. It forms 

 exactly half of the total length of the animal. The first four coxal 

 plates are deep and vertical, while the last three are narrow and much 

 everted, giving a fictitious appearance of breadth to this portion of the 

 body when seen from above. 



The first of the ahdorninal segments is as long as the last thoracic, 

 but the second and third are considerably shorter, while the remaining 

 three are very short, the fifth being not half the width of either the 

 fourth or sixth, and with difficulty distinguishable from the former. 

 The telson forms a deeply cleft, semilunar plate, which appears to be 

 movably articulated to the sixth segment. 



The a^itennce and antennules are long and slender, but unequal. 

 The antennules, much the shorter, equal the first six thoracic segments 

 in length. The peduncle consists of a short spindle-shaped basal joint 

 and two slender distal articulations, of which the first is nearly four 

 times as long as the second, which is with difficulty distinguishable 

 from the flagellum. This latter consists of ten very slender articulations. 

 The antennce are as long as the body less the last four abdominal segments. 

 The peduncle consists of five joints, of which the first two are very short, 

 completely hidden behind the projecting anterior border of the cephalon. 

 The third joint is long and thick and the fourth and fifth very long 

 and slender, so that the flagellum forms much the shorter portion of the 

 organ. This latter is but little longer than that of the antennule and con- 

 sists of 14 or 15 slender somewhat shorter articulations. 



The gnathites are rather small and are more adapted for sifting and 

 retaining finely divided material than for biting and cutting. The 

 mouth is guarded in front by a blunt triangular plate, which appears to 

 be immovably connected with the anterior surface of the head. The 

 mandibles are provided with a four- jointed hirsute appendage and 

 with two plates, of which one has a simple cutting edge of no great 

 power, perfectly smooth for its posterior half, but worn in front into 

 a series of irregular dentations. The second plate has a more complex 

 structure. In front it is provided with two stout conical teeth, the 

 more anterior being quite plain and smooth, while the posterior, 

 which is more slender and pointed, has its posterior border minute- 



