REVISION OF L.M.B.C. AMPHIPODA. 423 



PONTOPOREIID^. 



Batliyporeia norvegica, Sars. 



Llanfairfecban, dug out of sand between tide marks 

 1/9/83 ; Port Erin, electric light ; Colwyn Bay ; off Gar- 

 wick Head, Isle of Man 24/9/92. Length 8^ mm. A 

 small one from the same locality measuring 4J mm. had 

 the characteristic acute and up-turned post, angle of the 

 third pleon seg. 



Bathyporeia pelagica, Bate = B.pilosa, Lind., inRep. III. 



Port Erin Harbour, abundant ; Colwyn Bay ; Llanfair- 

 fecban; Menai Straits. Length of ovigerous females from 

 2 mm. to 42" mm. Males with fully developed antennae 

 from 3 mm. to 4 J mm. from the same locality. 



This is the commonest form of what with all deference 

 to Prof. Sars' superior knowledge I cannot but consider 

 with Mr. Stebbing to be but one species, viz., B. pilosa, 

 Lindstrom. The differences that Sars indicates between 

 B. pelagica, B. robertsonii, B. gracilis and B. pilosa 

 depending mainly on the colour of the eyes and the 

 presence or absence of the small spines on the first urus- 

 segment appear to me insufficient for specific distinction. 

 I have known the red eyes of B. pelagica turn white in 

 some specimens (and not in others) after two days in weak 

 spirit and glycerine while in other specimens they become 

 dark. The eyes of the specimen marked B. pelagica in the 

 Sp. Bate Collection in the British Museum are large and 

 dark — this is an adult male. In the same collection are 

 eleven specimens in one tube marked B. pilosa (Lind.) 

 some of which have, and others have not the spines on 

 the first urus-segment. One large female has a rudimen- 

 tary tooth on the lower margin of the third pleon segment. 

 B. pelagica {pi pilosa) becomes sexually mature at a very 

 early period, specimens only two mm. long containing one 

 to three ova having been dredged by I. C. Thompson on 

 June 19, 1892. 



