122 



Gen. 1. Pontoporeia, KrOyer, 1842. 



Body rather slender, somewhat resembling iii form that of the ty])ical 

 Lysianassidae. Coxal plates densely setous on the distal edge, the 4 anterior pairs 

 nearly of uniform size and subtruncate at the tip ; 5th pair witli the anterior 

 lobe the larger and more or less deflexed. Antennae rather powerful, subequal in 

 length, the joints of the peduncle in both pairs sharply' defined and furnished with 

 long ciliated setae; accessory appendage of the superior ones small. Mandibles 

 short and stout, with the masticatory part greatly expanded and furnislied with 

 a series of curved spines between the cutting edge and the molar expansion ; palp 

 rather slender and densely setous. First jiair of maxillae with tlie terminal 

 joint of the palp spathulate, and armed at the tijD with .short spines; basal 

 lobe not very large. Second pair of maxillae with the outer lobe much broader 

 tlian the inner. Maxillipeds with the masticatory lobe spinous on the inner 

 edge, and nearly I'eaching to the end of the antepenultimate joint of the palp; the 

 latter ratlier stout, with the penultimate joint short and Ijroad, strongly incurved, 

 dactylus smalh (linathopoda rather different in structure: the anterior ones 

 very short and densely setous, carpal joint laminarly expanded, propodos 

 comparatively small, without an\' distinctly defined palmar edge, dactylus 

 suuall and feeble; posterior gnathojxiihi more .slender than the anterior, pro- 

 podos narrow and produced beneath tlie small dactylus so as to approach 

 a chelate character. The 3 posterior pairs of pereiopoda rather dissimilar, 

 penultimate pair by far the longest, basal joint of this and the preceding 

 pair rather narrow, that of hist ])air, however, much expanded, clypeiform, 

 and edged with long ciliated setae; dactylus in all ;} pairs very smalh Ijast 

 ])air of uropoda short, l)oth rami uniaT'ticnhite, the outer the larger. Telson 

 si|unmiform and deeply cleft. 



Beniarhs. — As to the external appearance tlie species of this genus 

 somewhat remind of certain Lysianassidae, and the genus was in fact referred 

 to that family hy Sp. Bate. In the structure of the oral parts, as also in 

 that of the antennae and legs, are however found several well marked charac- 

 teristics to distinguish It from the Lysianassidae, and all recent authors therefore 

 now agree in regarding the genus as the t3'pe of a separate family. It is exclu- 

 sively i-epresented in the northern seas, and compi-ises as 3'et only 2 species, 

 both of which belong to the Norwegian fauiui. 



