8 W. :\r. TATTET^SATJ>. 



maturity concern cliieflN' tlie rostnim and tlic antennulcs, ainl tlicse notes refer to these 

 organs more particularly. 



The smallest recognisable specimen of E. superha measured 12 "5 mm. in length. 

 The anterior end is represented in Plate I., Fig. 4. The rostrum is a bluntly rounded 

 triangular plate. The spine u\\ the outer distal corner of the basal joint of the 

 antennule is still lar\al in character, being much longer than in larger .specimens. 

 There is mi Irai-c ol' tlic lobe from the basal Joint of the antcnnidc, but the one from 

 the second joint, alrcad\- shows as a slight membranous projection of the anterior 

 margin. The antennal scale also shows larval characters in that the outer margin 

 is shorter than the inner. Finally, the telson has assumed adult form, but the dorsal 

 spinules immediately anterior to the sub-apical spines are still long and plumose. The 

 lateral spine of the carapace is present, but small. Between 12 '5 mm. and 15 mm. 

 the spine on the basal joint of the antennule gradually shortens up and assumes the 

 characters seen throughout adult life. The antennal scale also assumes adult form, 

 and the spinules immediately anterior to the SLi1>apical spines on the telson lose their 

 plumose character and .shorten to adult size. The rostrum, however, still remains 

 oljtusely rounded. 



The next stage is that described by Sars as E. aiitarctica, and measures 17 mm. 

 The rostrum has now become a broad, acutely pointed triangular plate, while the lobe 

 from the basal joint of the antennules first becomes evident as a slight inflation of the 

 anterior margin. This is shown Ijy Sars in his 'Challenger' Report (Plate XV., 

 Fig. 2). lie has, however, overlooked the lobe on the second joint of the antennules, 

 which is now considerably forward in development. The spine on the lateral edge of 

 the carapace is now quite conspicuous. 



Sars describes E. aiitarctica as being without lateral denticles. Examination of 

 his type specimen, however, shows that, while the side from which he took his 

 figure is rather damaged and the spine not visible, on the other side the 

 spine is c|uite conspicuous and perfect. This removes the only serious difference 

 which existed between the young E. supcrba here noted and Sars' description of 

 E. aiitarctica. 



The transition from E. a/ifarcdca at 17 mm. to E. glacialis, Hodgson, is simple 

 and obvious. I figui'e (Plate I., Fig. ;5) the anterior end of a typical glacialis stage 

 from a specimen 20 mm. in length. The only differences to l)e noted from the 

 aiitarctica. stage are the better development of the antennular lobes and the shortening 

 and liroadening of the rostrum, which is still, however, pointed at the apex. The stage 

 figured agrees well with Hodgs(m's figures and description of E. glacialis. 



After a length (jf about 27 mm. the sides of the rostrum gradually become more 

 and more concave till at about JiO mm. the completely adult form is reached. Very 

 little change takes place in cither the form of the rostnim or the antennular lobes after 

 a length of 35 mm. has been attained, except, of course, in the changes accomjjanyiug 

 the hist two or three moults in tlie male, alreadv noted above. Examination of the 



