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 13 '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 setae ; 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 cresceutic depressions, above the origin of the antennas 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 



