EUPHAUSIA SUPERB A 217 



and keeled in the mid-dorsal line (Fig. 16 a). The front part is produced at the antero- 

 lateral corners into strong projections one behind each eye. In old heavily chitinized 

 males the projections are softened or disappear as such, because their margins have 

 become turned upwards and backwards. The rostrum is short and triangular and may 

 be a little shorter in the male than in the female. In old heavily chitinized males, and 

 much more rarely in females, the lateral denticles of the carapace are reduced or 

 wanting. 



b a 



Fig. 16. E. siiperbti. a, front part of carapace and antennular peduncles of female 

 from above, x 10. 6, left antennular peduncle of male from above, xii. 



The antennular peduncles differ a little in the two sexes, but they are very variable in 

 both, as a comparison of the accounts and drawings of Sars (1885), Tattersall (1908), 

 Hansen (19 13) and Rustad (1930) shows. My description of them is based upon an 

 examination of fresh material as well as upon these earlier accounts. In both sexes the 

 characteristic structures are stronger in young specimens than in old. 



The antennular peduncle of the male (Fig. 16 b) is somewhat stouter than that of the 

 female (Fig. 16 «). The lobe of the first segment is wide and strongly vaulted; it is 

 usually a little narrower than the second segment, but it may be as wide ; its length varies 

 from less than one-quarter to one-half the length of the second segment. Its shape is 

 variable, but it is mostly longer on the inner side than the outer so that its distal margin 

 is oblique ; it is usually emarginate too. There may or may not be a short strong spine 

 or a blunter tooth-like projection at the outer distal corner of the first segment of the 



