ISOPODA. 45 
groups. The dactylus, however, has its ventral margin furnished with small close 
set spines, and instead of the terminal claw there is a group of three large spines. 
The three posterior pair of limbs are rather long, graduating in length from first 
to last; the last is smallest, the middle one is 18°5 mm. in length. The joints are 
not specialised, except that the carpus has a series of seven or eight stout curved 
spines on its ventral surface; the propodus is similarly provided, and the dactylus, 
which is slender, is as long as the propodus and bears a small claw with a smaller 
accessory. 
The specimen is a male, and there is a long median process about 3 mm. long 
in front of the pleopoda ; this is thin, but has a slightly irregular outline and the 
extremity is rounded; it is cleft for one-third of its length. 
The first pair of pleopods have a protopodite about as long as the process 
above described, the exo- and endopodites are thin plates subequal in size with 
truncated ends, and these are fringed with long sete; the exopodite is much the 
strongest of the two. These have been examined in situ. 
The single specimen is a male, and was taken in 300 fathoms off the Great 
Ice Barrier, Bottom Mud, January 27, 1902. 
GLYPTONOTUS. 
This genus was established by Eights about 1852 for a large species captured in 
the South Shetland Islands. It subsequently received other species, but these have, 
for some time past, been transferred to other genera, and the following species, first 
found on the French Antarctic Expedition, is the only other one that can be now 
assigned to it. 
GLYPTONOTUS ACUTUS. 
(Plate VII.) 
Glyptonotus acutus Richardson (12), pp. 10-13. 
Specific characters :— 
Body more than twice as long as broad. 
Sculpturing exactly as in G. antarcticus. 
Urosome longer than broad, terminating in a prolonged spike. 
Legs very long and slender. 
Cephalosome is comparatively small, rounded posteriorly, being largely recessed 
into the first segment of the mesosome. The anterior margin is formed by two 
shallow crescentic depressions, above the origin of the antenne these depressions are 
united in the middle line by a stout tubercle, and a smaller one occurs at the 
external border ; from this the margin of the cephalosome slopes obliquely backwards 
to the posterior rounded margin in a slightly sinuous line. 
The eyes are quite small, ovoid, and dorso-lateral in position ; they lie on an oval 
swelling separated from the rest of the lateral plate by a shallow groove. The 
