I 9 2I.] 



Fauna of the Chilka Lake: Amphipoda. 



555 



In recording his specimens of Photis longicaudata from Ceylon Walker stated 

 that they were remarkably variable and it was a question whether that species should 

 not be merged with others in the oldest 

 recorded form, P. reinhardi Kröyer. At 

 the same time he described a new species, 

 P. longimanus, characterised mainly by the 

 short stout second gnathopod and the 

 structure of its carpal joint and the oval 

 lobe arising from it. Later on Stebbing 

 described a new species P. dolichommata 

 from the east coast of Australia which 

 appears to be closely related, but is dis- 

 tinguished by the greater length of the 

 ocular lobes and by the more numerously 

 jointed flagella of the antennae and the 

 setose furniture of the limbs, etc. Bar- 

 nard has since recorded P. longimanus 

 Walker from Durban Bay, South Africa, 

 but has pointed out various characters in 

 which his specimen differed from Walker's 

 description, describing also a form he considers to be an immature male which 

 shows characters nearer to those of Walker's specimens. But for this intermediate 

 form Barnard says that he would have felt bound to make a new species of his 

 other Durban specimens. Barnard also records P. dolichommata Stebbing from 

 Cape St. Blaize, South Africa. 



It seems likely from these facts that in the genus Photis we are dealing with 

 forms that are very variable and that as new specimens are found, it will be increas- 

 ingly difficult to divide them into separate species. 



The species P. longicaudata as understood above is widely distributed in the North 

 xAtlantic, Mediterranean, Indian Ocean and at South Africa. 



Fig. 12. — Photis longicaudata. 



a. Second gnathopod of male. 



b. Second gnathopod of female. 



Corophium triaeonyx Stebbing. 



Corophium triaeonyx Stebbing, 1904, p. 25. pi. 6a. 



Locality. Manikpatna, i6-ix-i3, 4ft. " Tubicolous Amphipoda from oyster shell." 

 Several specimens. 



These specimens undoubtedly belong to Stebbing' s species from Ceylon. They 

 agree well with his description and figures and also with a co-type that Mr. Stebbing 

 has been good enough to send me. In the male the second antennae agree closely 

 with that of C. crassicome Bruz., a species which is common in Europe, etc. It is 

 doubtful whether C. triaeonyx is more than a local variety of C. crassicome, but the 

 third uropods are considerably narrower than in the latter species. 



Walker (1904, p. 294) has recorded C. crassicome Bruz. from Perija Paar Kerrai, 



