6 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
description and figures is very close, almost the only noteworthy discrepancy being 
that the endopod of the uropods bears on its inner edge a series of spines, up to nine in 
number, of which only the distal one persists in the specimen figured by Zimmer. The 
elevated portions of the surface of the carapace are rugose. As in the specimen recorded 
from the “ Terra Nova " Expedition I can find no trace of corneal lenses on the ocular 
lobe. 
Zimmer lias figured a young specimen (8 mm. long) smaller than the holotype 
of Hansen’s C. glacialis, but agreeing with the adult in the sculpturing of the carapace. 
None of the specimens that I have examined show any marked difference in this 
character. It seems not impossible, however, that a re-examination of Hansen’s type 
would show some trace of the separation of “ Hocker 2 ” from “ Hooker 3 ” (in 
Zimmer’s terminology), which separation is, at present, the only character available 
for distinguishing C. gigas from C. glacialis. 
Distribution. —Lat. 66° 2' S., Long. 89° 38' E; 385 metres (“Gauss”). Lat. 
77 46' S., Long. 166° 8' E.; 300 fathoms (“Terra Nova"). 
Diastylis Mawsoni, sp.n. 
(Plate NIX.) 
Occurrence. —Stat. II, 3 9 • 
Description.— -Immature female; total length, 18 mm. (An ovigerous female 
measures 16 mm.) 
Carapace inflated, about one-third of total length, its height about two-thirds 
and its width about three-fourths of its length. Dorsal surface strongly vaulted in 
its posterior third, flattened and sloping downwards anteriorly. Surface marked with 
ridges which, in places, pass into an irregular reticulation, partly filling up the spaces 
between the main ridges. The strongly convex posterior part of the dorsal surface 
has two very prominent longitudinal ridges converging forwards, between which is a 
deep depression. From these, three oblique ridges pass downwards and forwards on 
the side of the carapace, the most anterior defining the flattened area of the dorsal 
surface. The third ridge is less regular in its course than the first and second, and 
behind it are some irregular reticulations which partly unite to outline a fourth oblique 
ridge. The lower ends of the first and second oblique ridges join with a somewhat 
irregular horizontal ridge, which runs forward to form a lateral keel on the pseudorostrum. 
A second horizontal ridge between the first and the lower margin of the carapace also 
runs a zigzag course, and is united with the first by a short vertical ridge. The flattened 
area of the dorsal surface is very rugose, and on it are a pair of longitudinal ridges close 
together, each giving off a forwardly-curved lateral branch. The pseudorostrum is 
short, obtusely pointed as seen from above, with its lateral margins pectinate. There 
