EUPHAUSIA G1I3UA. 245 



as long as tlio diamct(>r of the small oyes; the gastric area, seen from the side, 

 somewhat feebly vaulted, and the median keel is well developed. 



Lobe from first antennular joint not half as broad as the end of the joint, 

 directed obliquely forwards, upwards, and somewhat outwards; not quite as 

 long as broad, somewhat obhque-triangular with the inner margin feebly convex; 

 the end very acute, and besides frequently with an extremely low tooth or 

 feebly produced, sharp angle near the base of the outer side. Second antennu- 

 lar joint abo\'e with the distal inner angle showing an extremely small, sharp 

 tooth; while at the outer side the lateral corner itself is rounded. Third joint, 

 seen from the outer side (fig. 2a), with the dorsal keel decreasing gradually in 

 height from the middle to its proximal end which is situated at some distance 

 from the end of second joint, thus nearly as in E. paragibba H. J. H., but the 

 distal part of the keel is a little higher than in the latter species. 



Dorsal process of third abdominal segment, seen from above, shaped as an 

 oblong-triangular, distally acuminate and acute plate, very far from half as long 

 as the fourth segment. Sixth abdominal segment as in E. paragibba. 



The copulatory organs (fig. 2b) differ extremely from those in all other 

 species of the genus. The terminal process (p'.) is unusually small, subcorneal, 

 thick at the base, and with the distal third slender, acute and suddenly bent 

 obliquely forwards and outwards; the heel is proportionately long and very 

 slender. The proximal process (p^) is very long and strong, thickened at the 

 base and then tapering nearly evenly to the acute end; somewhat before its 

 middle it is curved somewhat inwards; and somewhat beyond the middle it is 

 bent considerably outwards and besides forwards, its distal third being almost 

 straight. The lateral process (p''.) is bent strongly inwards a httle before the 

 middle; its proximal part is thick, its distal part slender, and it has no dorsal 

 tooth. The median lobe is very curious; its proximal third, to the insertion of 

 the lateral process, is extremely broad, its middle third is considerably narrower, 

 yet broader than long; the distal third originates from the outer distal angle of 

 the preceding part as a kind of thin-skinned, very slender finger with the proximal 

 half directed considerably outwards and the distal part bent conspicuously 

 inwards. The auxiliary lobe of moderate length ; the setiferous lobe as in allied 

 species, with seven setae along its triangularly produced terminal margin. 



Length of adults of both sexes 11-15 mm., most frequently 12-13.5 mm. 



Remarks. — E. gibba G. O. S. is closely allied and very similar to E. pseudo- 

 gibba Ortm., E. hemigibba H. J. H., and E. paragibba H. J. H. These four species 

 are in reality so similar in general aspect, in shape of rostrum, size of eyes, lobe 



