530 



increasing in length, and having the basal joint large and laminar. Branchial 

 lamellae comparatively small ; incubatory lamellae narrow. Last pair of uropoda 

 not very much elongated, and having both rami uniarticulate and lanceolate 

 in form. Telson rather elongated and deeply cleft, each half bidentate 

 at the tip. 



Remarks. The systematic position of this genus, established by 



Sp. Bate, appears somewhat doubtful. Sp. Bate arranged it within his family 

 Plioxides, comprising a number of widely different Amphipoda, and Boeck 

 regarded it as a member of the family Leucothoidce. Mr. Stebbing, having 

 restricted the family Leucothoidce to the genus Leucoflioe, retained the present 

 genus within the remnant of Boeck's family Leucothoidse, for which he 

 proposed the name of Eusiridce. The very fully developed accessory appendage 

 of the superior antennas, as also the more or less conspicuous sexual difference 

 in the structure of the gnathopoda, would, however, seem to remove this 

 genus rather widely both from the genus Eusirus and Khachotropis, and to 

 bring it nearer to the family Gammaridce, its species having, indeed, an unmistak- 

 able resemblance, at least in external appearance, to those of the genus 

 CJieirocratus. In the structure of the oral parts it differs, however, considerably 

 both from this genus and the other Gammaridse, and in this respect it 

 exhibits in fact a close resemblance to the genus Leucofhoe. Perhaps there- 

 fore, the genus should more properly be regarded as the type of a separate 

 family, and such a view is in fact supported by the existence of a very 

 nearly-allied genus, Idunella, to be described below. The Gammarus 

 bispinosus of Costa would seem to belong to the present genus, and Mr. 

 Stebbing has added 2 new species from the Challenger Expedition. Another 

 species has recently been described by Mr. Norman as L. picta. To the 

 fauna of Norway belong 4 species, to be described below, one of which is 

 now for the first time established. 



26. Lilljeborgia pallida, Sp. Bate. 



(PI. 187). 

 Gammarus pallidus, Sp. Bate, Brit. Aesoc. Report 1855, p. 65. 



Syn: Gammarus brevicornis, Bruzelius. 

 Iduna brevicornis, Boeck. 



Body rather stout and highly compressed, with the 2 anterior 

 segments of metasome and the 1st of urosome each produced dorsally to a 

 small dentiform projection. Cephalon scarcely attaining the length of the 



