122 



DISCOVERY REPORTS 



Gnathiphimedia sexdentata, Schell. 



Schellenberg, 1926, p. 331 ; 1931, p. 116. 



Barnard, 1930, pp. 353, 449, fig. 27 {pacifica, non Stebb.). 



? Walker, 1907, p. 27 {pacifica, non Stebb.). 



? Chevreux, 1913, p. 118 {pacifica, non Stebb.). 



Occurrence: 1. St. 123. South Georgia. 1 ^ 10 mm., 1 $ 11 mm. 



2. St. 148. South Georgia. 1 $ 11 mm. 



3. St. 149. South Georgia. 1 $ 9 mm., 1 ovig. $ 11 mm. 



4. St. 156. South Georgia. 1 £ 10 mm. 



5. St. 170. South Shetland's. 1 $ 11-5 mm. 



6. St. 175. South Shetlands. 1 $ 11-5 mm., 1 $ 13 mm. 



7. St. 190. Palmer Archipelago (90-130 m.). 1^11-5 mm. 



8. St. 190. Palmer Archipelago (315 m.). 1 <$ 13 mm., 1^15 mm. 



Remarks. These specimens are all smaller than those of the Terra Nova collection, 

 but otherwise they are in agreement. In most the side-plates 1 and 2 are as figured 

 (1930), but in some cases side-plate 1 is truncate and slightly concave below, and side- 

 plate 2 is subtruncate. There is no trace of a dorsal keel on pleon segments 1-3. 



I am now convinced that neither the Terra Nova nor the Discovery (1925-7) 

 specimens should be identified with pacifica, Stebb. There can be little doubt that 

 Walker's specimens, also from McMurdo Sound, are the same as the Terra Nova 

 specimens; and in all probability the Pourquoi Pas specimens from Marguerite Bay 

 should also be referred to sexdentata. 



Distribution. 'Gauss' winter station, 385 m.; McMurdo Sound, 256-547 m. 

 Probably also Marguerite Bay, 50-200 m. 



Gnathiphimedia macrops, n.sp. (Fig. 68). 

 Occurrence: St. 42. South Georgia. 1 g 11-5 mm. 



Description. Resembling sexdentata (cf. Barnard, 1930, fig. 27, as pacifica) as re- 

 gards the dorsal armature and gibbous pleon segment 3 , 

 and 2nd joints of peraeopods 3-5. Antero-lateral margin 

 of head with a narrow notch separating a rounded tooth 

 above and a long acute tooth below. Eyes very large. 

 Side-plate 1 oblong, lower margin concave, denticulate; 

 side-plates 2-4 serrulate on lower anterior margins. 

 Mandibular apex obtusely conical, strongly chitinized. 



Remarks. Chevreux (1913) found the eyes of /. 

 margueritei much larger in <$ than in $. In the same 

 species from the Terra Nova collection I found the eye 



in the $ slightly larger than in the $; but in no other species in that collection, nor in 

 any of those in the present collection, is there any appreciable difference in the size of 

 the eyes in the two sexes. I am therefore inclined to regard the large eye in the present 

 form as a specific character, though the specimen happens to be a c?. 



Fig. 68. Gnathiphimedia macrops, n.sp. 

 Head with side-plates 1-4. 



