463 



others within a nearly-allied, new genus, the one here proposed. It may be 

 chiefly characterised by the comparatively slender antennae, the superior of 

 which do not exhibit any trace of an accessory appendage, the rather small 

 and slender palps of the mandibles and maxillipeds, the likewise rather feeble 

 gnathopoda, and the form of the telson. Besides the 5 Norwegian species 

 described below, several exotic forms have been recorded by different 

 authors as belonging to the genus Atylus, most of which may be more pro- 

 perly referred to the present genus. 



1. Paratylus Swammerdami (M-Edw.). 



(PI. 163). 



Amphithoe Swammerdami, M-Echvards, Ann. Sc. Nat. XX, p. 378. 



Syn.: Amphithoe coinpressa, Lilljeborg. 

 Paramphithoe compressa, Bruzel. 

 Dexamine Gordoniana, Sp. Bate. 

 > Dexamine Loughrini, Sp. Bate. 

 Atylus Swammerdami, Sp. Bate. 



Body comparatively short and stout, and highly compressed, with 

 none of the segments of mesosome or metasome elevated dorsally. First 

 segment of urosome having, as in the other species, at the end dorsally a 

 triangular projection, in front of which there is a deep notch denned above 

 by another but much smaller projection. Cephalon about the length of the 

 first 2 segments of mesosome combined, rostral projection rather short, anterior 

 edges of cephalon minutely bilobate, both lobes rounded. Anterior pairs of 

 coxal plates in female rather large, fully as deep as the body, in male much 

 smaller; 1st pair scarcely tapering distally and, like the 2 succeeding ones, 

 oblong quadrangular in form, though rather smaller; 4th pair slightly 

 emarginated posteriorly in their upper part, and forming below the emargina- 

 tion a very slight expansion truncated at the tip ; the 3 posterior pairs much 

 smaller than the anterior, anterior lobe of the antepenultimate pair rather 

 deep, and narrowly rounded at the tip. Last pair of epimeral plates of 

 metasome produced at the lateral corners to an acute point, posterior edge 

 nearly straight. Eyes oblong reniform, considerably larger in male than in 

 female, pigment dark brown, with a whitish coating. Superior antennas in 

 female considerably exceeding l /s of the length of the body, 1st joint of the 

 peduncle somewhat longer than the 2nd, flagellum not quite twice as long as 

 the peduncle, and composed of about 24 articulations carrying very small 

 bristles. Inferior antennae but little longer than the superior, last joint of 



