COPEPODA FROM IFALUK ATOLL 225 



Legs 2 to 4 (figs. 88h-j) are as in Robertgurneya rostrata (see below) ; 

 the setal formula is: 



endopodite exopodite 



leg 2 1.1.121 0.1.123 



leg 3 1.1.221 0.1.123 



leg 4 1.1.121 0.1.223 



Leg 5 (fig. S8k) with exopodite twice as long as broad; baso-endopo- 

 dite reaching along % of exopodite. Exopodite with 6 setae; 2 are 

 lengthened. Baso-endopodite with 2 apical setae of unequal length 

 and 3 internal setae. 



Color completely faded, greenish transparent. 



Remarks. — This species has a great general resemblance to Robert- 

 gurneya rostrata, but differs in the general shape of the body, the longer 

 antennules, and particularly the shape of leg 5. 



R. spinulosa has been recorded so far from Korshavn on the 

 Skagerrak coast of Norway (Sars, 1911) and from Gullmar Fjord on 

 the Skagerrak coast of Sweden (Lang, 1948). The present record is 

 from a sand sample some 340 feet from the reef margin on Falarik in 

 the Ifaluk Atoll. On both of the previous occasions the species was 

 found also on sandy bottom in depths varjdng from 70 to 30 m. The 

 female specimens recorded by Sars and Lang measured 0.55 mm. 



Robertgurneya rostrata (Gurney, 1927) 



Figures S7d,e, 89-91 



Amphiascus rostratus Gurney, 1927, p. 527, fig. 144.— Monard, 1928a, pp. 378, 

 386.— Willey, 1935, p. 62, figs. 40-47.— NichoUs, 1939, p. 260.— Sewell, 1940, 

 pp. 358, 369, 380. 



Amphiascoides rostratus. — Nicholls, 1941b, pp. 71, 72, 73, 81, 83. 



Robertgurneya rostrata. — Lang, 1948, p. 703, fig. 283 (no. 3). 



Amphiascus ctenophorus Mouard, 1928, p. 395, fig. 34 (no. 2); 1928a, p. 383. — 

 Nicholls, 1939, p. 260.— Sewell, 1940, pp. 282, 358, 366, fig. 64. 



Material.— Log. 592, 2 ad. 99, 0.41 and 0.42 mm.; 4 ad.cT cT, 

 0.38-0.48 mm. (0.43 mm.); 3 99 cop. stage V, not measured. 



Description. — The female is based on the two female specimens 

 mentioned above; both have been dissected. The male of 0.48 mm. 

 was also described and dissected. 



Adult female, total length 0.41-0.42 mm. 



Body moderately slender, with ovoid cephalothorax and narrower 

 abdomen, both regions distinctly separated. Greatest diameter of 

 body at 2nd thoracic somite, narrowing on both sides (fig. S7d). 

 Head and 1st thoracic somite fused, as long as combined lengths of 

 thoracic somites 2-4. Line of back in lateral view curved (fig. 89a), 

 rostrum separated from back by deep groove, visible both laterally 

 and dorsally. Rostrum long, triangular with blunt apex, well visible 

 in dorsal view, pointing forward and sHghtly downward, as long as 



