318 Mr. C. Spence Bate on a new genus and some 



2. E. bipunctattis, Linn.j Gyll., Steph., Schonh. 



There are two foreign specimens in the collection of Kirby sent 

 by Gyllenhal. 



Plentiful on the gray sallow {Salix cinei-ea), Bishop's Wood, 

 Hampstead, in June. 



XXXIII. — On a new genus and several new species of British 

 Ci-ustacea. By C. Spence Bate. 



[With a Plate.] 



Bellia arenaria. 



Gen. Char. Back broad, round and smooth. Upper antenna forked. 

 Lower antenna ciUated, having the second joint flattened. 

 First pair of feet simple : second and third pairs didactyle, 

 remainder simple. The three anterior pairs of feet much 

 smaller than the rest ; the lateral appendage to each annular 

 segment, together with the joints of the three last pairs of 

 feet, largely developed, so as to appear like scales. Natatory 

 feet an-anged in double parallel pairs. 



This animal bears a nearer resemblance to the genus Talitra, of 

 which it probably may be a subgenus, than to any other among 

 the order of the Amphipoda, although I think it oiFers too many 

 vei-y distinctive characters to admit of its being considered as a 

 species of that genus. It is stouter in body and shorter in length 

 than Talitra. The upper antenna is shorter than the lower and 

 has two filaments ; the second joint of the lower antenna is large, 

 flat and thin, a peculiarity which is extended to the first joint 

 of the fourth and fifth pairs of legs, as well as the first, second 

 and third joints of the sixth pair, whilst the third, fourth and 

 fifth joints increase in diameter at their lower extremity. The 

 fu'st pair is small and folded in as if attendant on the mouth; 

 the second and third pairs are shorter and more slight than 

 those posterior to them, and terminate in a didactyle claw of 

 peculiar form ; its shape carrying out a character peculiar to 

 this genus, and differing from that most general, wherein the 

 finger of the forceps is sharp and pointed. We find that in this 

 animal the joint from a narrow point increases in diameter 

 towards the terminal extremity, upon being reflected back against 

 the penultimate, where instead of impinging against a sharp pro- 

 ees.s, as is usually the case, even where most rudimentaiy, it is 

 here met by an obtuse but thin, flattened and ciliated edge. 



The peculiar habits of this genus exhibit the modification of 

 its several parts to be adapted to required conditions. 



