(-') 1" '' tin- rostrum is shorter and blunter than in K. mumn/i, and 



tin- margins lc-~ .li.|.|\ .-..n.ave. This, a^ain, is clearly shown to le a s- 

 litlcrcinT in I'l I., Fiji's. I ami _'. The rostrum of the male figured (Fig. 2) IB shorter 

 than that of the female. I. in i> still rather more acute than in Saw" figure of K. *i*/rrfa. 

 Redn, ti-.M is probably not complete till a size of at least 48 mm. is attained. 



A further ditlcren.-e 1,,-tween the two sexes is brought out by the figures here 

 given, namely, the reduction in the male of the spine on the outer distal corner of the 

 basal joint of the aiiteiuiular peduncle. It is not visible in dorsal view, Iwing hidden 

 l.y the slightly j.mj.rtmg anterior margin of the joint, but it still persists as a small 

 1-liint protuberance. In the female, on the contrary, it is well-developed, distinctly 

 \ isilih- in dorsal view, and acutely pointed throughout life. 



A fourth distinction shown in the figures, the absence in the female of the curved 

 setae on the dorsal surface of the basal joint of the antcnuules, is due to the accident 

 that in the female from which the figure was taken, these setae had Iwcome broken off. 

 They are, in reality, present, and equally developed in lx>th sexes. 



The above detailed description proves, I think, clearly, that E. su/terhi and 

 E. murrayi are the adult male and female, respectively, of one species which must lear 

 the name E. superba Dana. 



I also give (Plate I., Figs. 5-9), figures of the mouth organs and cndopods of the 

 first two thoracic limbs, to show two characters in which E. superba differs from all 

 other Euphausia yet described. The first of these points is the narrow and elongate 

 form of the terminal joint of the mandibular palp, with its peculiar armature of four or 

 five terminal strong plumose set. In all the other species of the genus (with the 

 exception of E. antarctica, Sars, and E. fflticialis, Hodgson), the terminal joint of the 

 mandibular palp Is much shorter and stouter. In the two exceptions just mentioned 

 the maudibular palp is figured by Sars and Hodgson respectively, almost exactly as 

 here given for E. superba. This fact first suggested to me that these two species were 

 only developmental stages of E. superba, a suggestion fully lorne out by the evidence 

 derived from a study of the present collection. The second distinctive character of the 

 appendages is found in the great length of the seta; arming the joints of the thoracic 

 limlis. They are very much longer than in any other species of the genus, and with 

 the character of the mandibular palp serve for recognition of E. superba at any stage 

 in its development. 



Euphausia superba is the giant of the genus, and the only one of Dana's original 

 four species which is now retained by Hansen (1905 (2) ), the other three having been 

 cancelled by that author as unrecognisable. 



Some Notes on the development of E. superba. 



These notes were made chiefly with a view to confirming the suspicion, aroused 

 by the similarity in mouth organs, that Euptuiuttia antnrclica and E. glacialis were 

 merely developmental stages of E. xuperba. The changes which accompany growth to 



E 2 



