118 



divergent, and conspicuously asymmetrical, the left one being the larger, and 

 having one of the apical setae excessively prolonged. Eye wholly wanting. An- 

 terior antennae greatly attenuated and abruptly curved in their proximal part; 

 left one in the male geniculate. Posterior antennae with the rami of not very 

 different length, the outer one 7-articulate. Mandibles with the cutting teeth much 

 reduced in number, the outermost one widely separated from the others and claw- 

 shaped, with a peculiar rim outside; palp well developed, with the inner ramus 

 shorter than the outer. Maxilke with the inner ramus of the palp quite rudi- 

 mentary, outer ramus greatly produced, and tipped with long setae. Anterior 

 maxillipeds exceedingly powerful, and armed in their distal part with strong, 

 anteriorly-curving claw-like spines, proximal digitiform lobes rudimentary. Posterior 

 maxillipeds scarcely longer than the anterior ones, and much narrower, with the 

 2nd basal joint very slender, terminal part 5-articulate, and clothed with com- 

 paratively short setae. Legs powerfully developed, outer ramus in 2nd to 4th 

 pairs very large, with the terminal joint considerably expanded, especially in the 







3rd pair, and having both the spines and the setae unusually short. Last pair 

 of legs in female considerably smaller than the preceding ones, outer ramus with 

 a slender falciform spine inside the 2nd joint; those in male somewhat larger, 

 with the outer rami subprehensile and without any natatory setae. 



Remarks. This genus was established in the year 1863 by Glaus, to 

 comprise 2 Mediterranean species. As, however, the generic name, Hetcrochccta. 

 proposed by him had been previously appropriated in Zoology, Dr. Giesbrecht 

 has recently changed it to Hetercrhabchis. It is a very distinct genus, easily 

 recognizable, among other things, by the peculiar asymmetry of the caudal rami, 

 and the excessive length of one of the apical setae issuing from the left ramus. 

 Dr. Giesbrecht enumerates no less than 13 species belonging to this genus, and 

 a 14th, H. compactus, G. 0. Sars, has been added by the present author from 

 Nansen's Polar Expedition. Only a single species belongs to the fauna of Nor- 

 way, and it will be described below. 



51. Heterorhabdus norvegicus (Boeck). 



(PI. LXXX & LXXXI). 



Heterarha'tii itnnryica, Boeck. Nye Slaegter og Arter af Saltvandscopepoder. 

 Chr. Vid. Selsk. Forh. 1872, p. 40. 



Specific Characters. Female. Body moderately slender, with the anterior 

 division, seen dorsally, oval fusiform in outline, greatest width somewhat exceeding 

 Ys of the length, and occurring about in the middle, anterior extremity gradually 

 narrowed and obtusely truncated at the tip, with a knob-like projection in the 



