1921] Fauna of the Chilka Lake : Amphipoda. 549 



pared his species with Microdeutopus gryllotalpa, M. websteri and other species of the 

 genus. The small tooth on the posterior margin of the carpus in my first specimen 

 is quite like the one figured by Sars in M. propinquus and at first sight seemed to 

 confirm the affinity of this species to Microdeutopus. At the time I had not looked 

 up Stebbing's description of Grandidierella bonnieri, but on doing so afterwards 

 found that the species, of which I was then about to examine further specimens, 

 agreed very closely in the characters both of the male and the female with Stebbing's 

 description and figures, and I feel confident that his species is the same as Microdeu- 

 topus megnae Giles. Stebbing referred his species to the genus Grandidierella which 

 had been previously established by Coutière for a specimen from Madagascar, and 

 following Coutière placed the genus under the Corophiidae. The general resemblance 

 of the animals to Microdeutopus and to Aora is so great that in my opinion the 

 genus should be placed under the Aoridae. The third uropods certainly are one- 

 branched, but I do not consider this sufficient to outweigh the resemblance in all 

 the other characters which, as will be seen from the following description, is very 

 close. Stebbing distinguished his species from Coutière' s by (1) the difference in 

 the accessory flagellum in the first antenna and (2) the different proportions of the 

 carpus of the first gnathopod of the male. From the examination of a large 

 series of specimens I find that the accessory flagellum, though fairly distinct and 

 perhaps sometimes nearly as long as the first joint of the main flagellum in im- 

 mature specimens, becomes reduced in more adult ones to a minute lobe with one 

 or two setae; Stebbing describes it in his specimens as being " microscopically small 

 but carrying one or two setules." It will be seen also from the description given 

 below that the shape and proportions of the carpus of the first gnatho pod of the 

 male vary very considerably during development, and in fully matured males the 

 proportions come very close indeed to those given by Coutière, and I therefore 

 consider his species a synonym of Grandidierella megnae (Giles) . In this species the 

 proportions of the antennae vary according to age much as they do in the genus 

 Aora. Figure 10a shows the antenna? of an immature male; the antennae are 

 seen to be subequal, the upper pair a little longer than the lower ; the second joint 

 of its peduncle is considerably longer than the first and narrower, all three joints of 

 the peduncle being fringed below with long setae ; the flagellum consists of 15 fairly 

 slender joints, the accessory flagellum being rather more than half the length of the 

 first joint. The lower antenna is somewhat stouter than the upper and similarly 

 fringed with long setae. In more adult males the second joint of the flagellum of 

 the upper antenna (fig. ioô) becomes more elongated, the first joint being stouter 

 in comparison and the third slightly shorter in proportion, the flagellum is greatly 

 elongated and more slender, the accessory flagellum being reduced to a minute lobe. 

 The peduncle, as will be seen from the figure, bears very few setae, a small group at 

 the end of the first joint on the lower side being the most conspicuous. The lower 

 antennae in the adult male (fig. 10c) become very stout and pediform with the last 

 two joints of the peduncle almost free from setae. The flagellum consists of about 

 five joints only and bears a number of stout curved spines which are hardly deve- 



