122 



Gen. 1. Pontoporeia, Kroyer, 1842. 



Body rather slender, somewhat resembling in form that of the typical 

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

 nearly of uniform size and siiLtruncate at the tip; 5th pair with the anterior 

 lobe the larger and more or less deflexed. Antemise 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 furnished with 

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

 rather slender and densely setous. First pair of maxillae with the terminal 

 joint of the palp spathulate, and armed at the tip witli short spines; basal 

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

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

 edge, and nearly reaching to the end of the antepenultimate joint of the palp; the 

 latter rather stout, with the penultimate joint short and broad, strongly incurved, 

 dactylus small. Gnathopoda rather different in structure: the anterior ones 

 very short and densely setous, carpal joint laminar ly expanded, propodos 

 comparatively small, without any distinctly defined palmar edge, dactylus 

 small and feeble; posterior gnathopoda more slender than the anterior, pro- 

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

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

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

 pair rather narrow, that of last pair, however, much expanded, clypeiform, 

 and edged with long ciliated setae ; dactylus in all 3 pairs very small. Last 

 pair of uropoda short, both rami uniarticulate, the outer the larger. Telson 

 squamiform and deeply cleft. 



Remark*. As to the external appearance the species of this genus 

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

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

 that of the antennae and legs, are however found several w r ell marked charac- 

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

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

 sively represented in the northern seas, and comprises as yet only 2 species, 

 both of which belong to the Norwegian fauna, 



