EUPHAUSIA LONGIROSTRIS 229 



end of the first segment of the antennular peduncle (Fig. 21 a). The gastric area of the 

 carapace is convex and strongly keeled in the mid-dorsal line ; the keel rises to a crest, 

 similar to but bigger than that of E. spinifera, in the position occupied by the dorsal 

 organ in the larval stages. The carapace is produced into a pair of strong post-ocular 

 spines behind and above the eyes. There are no hepatic spines, but in the position 

 occupied by them in E. spinifera and E. lotigirostris there is a low mound-like projection 

 rounded off on all sides but the anterior, where it ends in a more abrupt way. There is a 

 single pair of lateral denticles set above an incision in the lower edge of the carapace. 



Fig. 21. E. lotigirostris. a, carapace and antennular peduncle from the side, x 13. 6, left antennular peduncle 

 from above, x 13. c, third to fifth abdominal segments from the side, x 8. 



The lobe of the first segment of the antennular peduncle is large and strong but 

 narrower than the second segment, above which it rises in an arch-like way (Fig. 21 a,b). 

 Its distal end is divided into two nearly equal spines ; a third and smaller spine may or 

 may not arise lower down on the outer margin of the lobe — in one individual one 

 antennule may have this spine and the other not ; it is sometimes nearly as strong as the 

 other two spines. A strong spine runs over the third segment from the middle of the 

 distal margin of the second ; there is a low keel along the distal part of the inner margin. 

 The dorsal keel of the third segment is high and strong. 



The terga of the first and second abdominal segments are produced into small, wide, 

 rounded projections mid-dorsally ; there is a very strong compressed spine-like process 

 from the third abdominal segment and much smaller spine-like processes, not com- 

 pressed, from the fourth and fifth segments. The posterior margins of the terga of the 

 fourth and fifth segments are deeply incised (Fig. 21 c). 



The terminal process of the male copulatory organ has a heavy foot-like base, bigger 



