8 
W. M. TATTERSALL. 
maturity concern chiefly the rostrum and the antennules, and these notes refer to these 
organs more particularly. 
The smallest recognisable specimen of E. superba measured 12 1 5 mm. in length. 
The anterior end is represented in Plate I., Fig. 4. The rostrum is a bluntly rounded 
triangular plate. The spine on the outer distal corner of the basal joint of the 
antennule is still larval in character, being much longer than in larger specimens. 
There is no trace of the lobe from the basal joint of the antennule, but the one from 
the second joint already 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 sub-apical spines on the telson lose their 
plumose character and shorten to adult size. The rostrum, however, still remains 
obtusely rounded. 
The next stage is that described by Sars as E. antarctica, 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 by Sars in his ‘Challenger’ Beport. (Plate XV., 
Fig. 2). He 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. antarctica 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 quite conspicuous and perfect. This removes the only serious difference 
which existed between the young E. superba here noted and Sars’ description of 
E. antarctica. 
The transition from E. antarctica at 17 mm. to E. glacialis, Hodgson, is simple 
and obvious. I figure (Plate I., Fig. 3) the anterior end of a typical glacialis stage 
from a specimen 26 mm. in length. The only differences to be noted from the 
antarctica stage are the better development of the antennular lobes and the shortening 
and broadening of the rostrum, which is still, however, pointed at the apex. The stage 
figured agrees well with Hodgson’s figures and description of E. glacialis. 
After a length of about 27 mm. the sides of the rostrum gradually become more 
and more concave till at about 30 mm. the completely adult form is reached. Very 
little change takes place in either the form of the rostrum or the antennular lobes after 
a length of 35 mm. has been attained, except, of course, in the changes accompanying 
the last two or three moults in the male, already noted above. Examination of the 
