ISOPODA. 45 



groups. The ilactylus, however, has its ventral luarj^nn furnished with small close 

 set spines, and instead of the terminal claw there is a grouj) of three large spines. 



The three posterior pair of lindjs 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 propjodus 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 aliout 3 mm. long 

 in front of the pleojMada ; this is thin, but has a slightly irregular <mtliue and the 

 extremity is rounded ; it is cleft for one-third of its length. 



The first pair of pleopuds 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 set£e ; the exop(jdite 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 oif 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. 



Glyptonotos acutus. 



(Plate VII.) 

 Glyptonotus acutus Richardson (12), pp. 10-13. 



Specific characters : — 



Body more than twice as long as broad. 



Sculpturinj;; exactly as in G. anlarcticus. 



Urosome longer than broad, terminating in a prolonged spike. 



Legs very long and slender. 



Cephalfjsome 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 antenna? these depressions are 

 united iii the middle line by a stout tubercle, and a smaller one occurs at the 

 external border ; from this the margin of the cephalo.some slopes oblicjuely backwards 

 to the posterior rounrled margin in a slightly sinuous line. 



The cynA are quite small, (^voiil, and ilorso-lateral in position ; they lie on an oval 

 swelling .separated from the rest of the lateral plate by a shallow groove. The 



