LYSIANASSIDAE 67 



crenulations passing into 2-3 separate stout spines on apex, palp 4-jointed, 4th joint 

 slender. 



Gnathopod 1 subchelate, 2nd joint straight, setose on anterior margin, 5th rather 

 elongate triangular, lower distal projection narrow, 6th oblong, parallel-sided, twice as 

 long as broad, palm transverse, straight or slightly concave, or even slightly convex, 

 obscurely crenulate, with 1-2 spinules at angle, finger slender, slightly overlapping 

 palm. Gnathopod 2 minutely chelate, 6th joint shorter than 5th, oblong. 



Peraeopod 3, 2nd joint subcircularly expanded, hind margin obscurely notched, 4th 

 joint not strongly expanded. Peraeopod 4, 2nd joint ovate, anterior margin straight, 

 hind margin obscurely notched. Peraeopod 5, 2nd joint ovate, but more strongly 

 expanded than in peraeopod 4. 



Uropods 1 and 2, rami subequal, acuminate, with a few spinules. Uropod 3 extending 

 slightly beyond apices of uropods 1 and 2, and beyond telson, upper outer margin of 

 peduncle rather expanded, convex, upper inner margin straight, with 2 spinules, inner 

 ramus, which is actually inserted above the outer ramus, as long as 1st joint of outer, 

 inner margins of both with plumose setae in both sexes. 



A single elongate accessory branchia on both segments 5 and 6. 



Allogaussia lobata, n.sp. (Fig. 26). 



Occurrence: 1. St. 142. South Georgia. 1 juv. 5-5 mm. 



2. St. 170. South Shetlands. 1 ? 13 mm. Type. 



3. St. 208. South Shetlands. 2 $$ 9-10 mm. 



Description. Like navicula, but larger. Eyes pale reddish. Side-plates as in naviatla. 

 Pleon segment 3 very similar to that of navicula as regards postero-inferior angle ; seg- 

 ment 4 with a more prominent dorsal keel which ends posteriorly in a rounded lobe 



Fig. 26. Allogaussia lobata, n.sp. a. Telson. b. Pleon segments 3-6. 

 c. Profile of epistome and upper lip. d. 2nd joint of peraeopod 3. 



overlapping segment 5 ; segment 6 with the dorso-lateral keels on either side of telson 

 more prominent. Telson longer than wide, cleft for two-thirds its length, the lobes 

 dehiscent, each with an apical spinule. 



Antennae 1 and 2, and mouth-parts as in navicula. Epistome not expanded proxi- 

 mally, its profile sinuous. 



