COPEPODA FROM IFALUK ATOLL 193 



From this list it would appear that a necessary restriction of the 

 genus Amphiascoides would meet with as many difficulties as in 

 Mesamphiascus , but, fortunately, it can be restricted because of its 

 clearly fixed type: Dactylopus dehilis. This type makes Lang's 

 genus Amphia^cella, type species Stenhelia neglecta (Norman and T. 

 Scott, 1905) {—Amphiascus linearis G. O. Sars, 1906), a sub- 

 jective synonym of Amphiascoides Nicholls, 1941. In this respect, 

 following other authors such as Noodt (1955, p. 74), I have rejected 

 the genus Amphiascella and substituted the generic name Amphias- 

 coides, type species Daclylopus dehilis Giesbrecht, 1881, and I have 

 applied to it the restricted diagnosis of Lang's former genus Amphi- 

 ascella. The species now attributable to this genus are discussed 

 on p. 232. 



Since the publication of Lang's paper, many new forms of Diosac- 

 cidae have been introduced; I have not, however, at this stage at- 

 tempted to assemble all information concerning these new species 

 since this would involve more time than I have available at present 



Genus Amphiascus Sars, 1905 



Amphiascus minutiis (Claus, 1863) 



Figures 71, 72 



Dactylopus minutus Claus, 1863, p. 126, pi. 16 (figs. 14, 15). 



Amphiascus minutus. — Marine Biological Association, 1931, p. 163. — Fraser, 

 1936, pp. 25, 26.— Nicholls, 1939, p. 261.— Sewell, 1940, p. 126.— Nicholls, 

 1941b, pp. 69, 74, 75, 77.— Lang, 1944, p. 15.— Dahl, 1948, p. 98.— Lang, 

 1948, p. 649, figs. 261 (no. 1), 262.— Klie, 1950, p. 76, figs. 53, 54.— Pet- 

 kovski, 1955b, p. 218. — Maghraby and Perkins, 1956, p. 491. — Marine Bio- 

 logical Association, 1957, p. 163.— Noodt, 1957, p. 153.— Roe, 1958, p. 229; 

 1960, p. 280. 



Material.— Loc. 589, 2 ov. 99, 0.39 mm.; 1 ad. 9, 0.32 mm.; 4 ad. 

 cfd', 0.29-0.34 mm. (0.32 mm.). Loc. 590, 1 ov. 9, 0.32 mm., 3 

 eggs. Loc. 591, 1 ad. 9, 0.39 mm.; 1 ad. d^, 0.27 mm. Loc. 594, 1 

 ad. 9, 0.31 mm. Loc. 638, 1 ad. 9, 0.27 mm. 



Description. — The following is based on the female specimen 

 from locality 591; some notes are added on an aberrant specimen 

 from locality 594. 



Adult female (from locaHty 591), 0.39 mm.; greatest diameter 

 0.09 mm. 



Body, especially in dorsal aspect, slender, greatest diameter at 3rd 

 thoracic somite, gradually narrowing anteriorly and posteriorly, 

 without distinct separation between cephalothorax and abdomen 

 (fig. 71a). Head and 1st thoracic somite fused, length equal to com- 

 bined lengths of thoracic somites 2 to 5. Line of back in lateral 

 aspect smoothly curved, sides produced to shield oral appendages 



