1888.] G. M. Griles— ^o^e^- on the Amphipoda of Indian Waters. 245 



distinct, oval leaflets, regularly articulated to the posterior border of 

 the last segment, and capable of free motion like an appendage. It is 

 possible that this power of thus erecting the telson may serve as a 

 substitute for the uropodal hooks of the associated AmphitJioe, enabling 

 the animal to hang on to the nest it has appropriated in much the same 

 way that species does by the latter means. 



The a^itennules and antennae are subequal and short, being hardly 

 more than a third of the body length, reaching back as far as the back 

 of the third thoracic segment. 



The antennules have the peduncle considerably shorter than the 

 flagellum, the first joint being long and stout, the second rather more 

 than half the length of the first, and the third joint so small as to be 

 almost indistinguishable from the flagellar articuli, which latter are 

 14 — 16 in number, short, and, like the peduncle, but feebly armed with 

 a few fine hairs. 



The first joint of the peduncle of the antennce is hidden behind the 

 projecting anterior border of the head and the next two are very short 

 and stout, while the remaining two pieces are long and slender and 

 subeqaal to each other and to the flagellum, which latter consists of 

 8 — 10 short articuli. Both peduncle and flagellum are somewhat more 

 strongly armed than the corresponding parts of the antennules. 



The gnathites are large and strong. The mandibles are simple in 

 construction, the biting plates having a straight, unserrated cutting 

 edge, while the triturating plate consists of a single row of simple blunt 

 teeth arranged in a vertical series with a tuft of compound, sifting 

 bristles behind them. They are provided with a long four-jointed 

 appendage. The first maxilla has the inner lamella strongly toothed 

 and almost mandibuliform, and the second maxilla has the outer ramus 

 but little flattened, and almost palp-shaped. 



The gnatliopoda (2nd and 3rd thoracic appendages) are of similar 

 form, with weak subchelce, the protopodite being simply dilated and not 

 produced into a distinct palm, but the anterior of the two is consider- 

 ably the smaller, its length only equalling that of the head and first 

 two thoracic segments, while the posterior is longer by the length of an 

 additional thoracic segment. The fourth and fifth thoracic appendages 

 are of the usual ambulatory type, but differ in length, the fourth being 

 subequal to the second gnathopod, while the fifth, the shortest of all 

 the thoracic appendages, is not quite as long as the first gnathopod. 

 The remaining three thoracic appendages closely resemble each other 

 in form, all having, as in the Amphithoe, dilated basipodibes taper- 

 ing below, and their remaining articuli long and slender. They differ, 

 however, somewhat in length, the seventh, the longeat of all the thoracic 



