ISOPODA. 17 



The gnathopod (fig. 3b) is a large, tapering six-jointed structure, articulated to 

 the body laterally and curved forwards over the mid-ventral line ; it is shielded 

 externally by a curved and projecting flange of the exoskeleton. The first joint is 

 short and stout, only indicated in the figure ; all the other joints except the terminal 

 one are large, flat,. and broad ; the first of these the second in point of size has a 

 fringe of small setae externally and six rather short plumose setse distally on the inner 

 margin. The next joint is the largest, and its inner margin is fringed with large 

 plumose setae ; externally there are a few small setae distally. The three following 

 joints are scarcely as long as the second, the terminal one being minute. Collectively 

 they taper to a blunt point ; the third has plumose setas all along the inner margin, 

 and small fine setae externally, the other two have these fine setae all around, bub the 

 penultimate one bears a group of long, simple setse near its distal extremity. 



The proportions of these joints are 4. G. 3. 2. 0'5. 



The pereiopoda are all very much alike. In the first pair the second and third 

 joints together are scarcely as long as the first, the carpus is about as long as the 

 preceding, the propodus is longer, the dactylus is about half its size. The proportions 

 are not quite the same on all the limbs, but in all cases the ischium and merus are 

 expanded on their outer margin ; in the merus this expansion becomes a forwardly 

 directed lobe. Small groups of setae occur on these swellings, and a few smaller ones 

 are scattered elsewhere. One or two small spines may occur on the propodus. 



A single specimen was taken off Coulman Island in 100 fathoms, 13th January, 

 1902. 



.EGA. 



This well-known genus, established by Leach in 1815, now contains some twenty- 

 five species from all parts of the world. The following species was first taken on the 

 French Antarctic Expedition. 



.EGA ANTARCTICA. 



(Plate II.*) 

 JEya australis Richardson (12), pp. 4-6, not Whitelcgge, Mem. Austral. Mus. iv. (1901), p. 229. 



Specific characters : 



No process on the propodus of the first three pair of pereiopoda. 

 The enlarged endopodite of the uropoda. 



This species, of which several specimens were taken, attains a length of 28 mm. 

 and a width of 13 mm. 



The cephalosome is small, its anterior margin is slightly rounded, and a stout but 

 short rostrum projects between the antennae ; its posterior margin is rounded, but not 

 quite evenly, the eyes are very distinct, rather small, lateral in position, and irregular 

 in shape. 



* The legend should be as above, and not as it was printed off. 

 VOL. v. K 



