180 U.S. NATIONAL MUSEUM BULLETEST 236 



The present new species approaches Idomene kabylica Monard, 1936, 

 in many respects. Yet a comparison with Monard's original diagnosis 

 reveals several points of difference, e.g., the 6-segmented antennules 

 with their long 3rd segment, differences in structm*o of the mandibular 

 palp, and small differences in the comparative lengths and shape of 

 endopodal and exopodal segments of the legs. There remain many 

 points of similarity, and the suggestion that the differences between 

 both species are due to incompleteness in Monard's description of 

 his only female specimen cannot altogether be avoided. Monard's 

 specimen, an ovigerous female, measured 0.7 mm. 



Family Parastenheliidae Lang, 1944 



This family, as it has been defined by Lang (1944, p. 13; 1948, 

 p. 584) has but a single genus, Parastenhelia Thompson and A. Scott, 

 1903 (=Microthalestris G. O. Sars, 1905; Thalestrella Monard, 1935a), 

 type species Harpacticus spinosus Fischer, 1860. Only this type 

 species occurs in the Ifaluk collection. 



Genus Parastenhelia Thompson and A. Scott, 1903 

 Parastenhelia spinosa (Fischer, 1860) 



Figures 64c, 66-70 



Harpacticus spinosus Fischer, 1860, p. 665, pis. 21 (figs. 51-53), 22 (fig. 66). 

 Parastenhelia spinosa. — Lang, 1944, p. 13. — Dahl, 1948, p. 96. — Lang, 1948, 



p. 588, fig. 240 (no. 1).— Klie, 1949, p. 126.— Gaspers, 1951, p. 65.— Noodt, 



1955a, p. 203. 

 Parastenhelia spinosa var. littoralis. — Dahl, 1948, p. 96. — Roe, 1958, p. 228; 



1960, p. 280. 

 Parastenhelia spinosa var. penicillata. — 'Roe, 1958, p. 228; 1960, p. 280. 

 Microthalestris littoralis. — VMova, 1928, p. 181. — Fraser, 1936, p. 26. 

 Parastenhelia littoralis.— Sewell, 1940, pp. 127, 129, 191, 357, 363, 365, 366, 



369, 370, 372-376, fig. 26. 

 Parastenhelia littoralis var. scotti Sewell, 1940, pp. 127, 195, 357, fig, 28. 

 Parastenhelia littoralis var. penicillata. — Sewell, 1940, pp. 127, 129, 189, 193, 



375, fig. 27. 

 Microthalestris forficula. — ^Fraser, 1936, pp. 25, 26. — Marine Biological Association, 



1931, p. 162; 1957, p. 166. 

 Parastenhelia forficula.— Sewell, 1940, pp. 127, 129.— Klie, 1941, p. 23.— Nicholls, 



1945, p. 3, fig. 2A. 

 Parastenhelia forficula var. littoralis. — Nicholls, 1945, p. 4, fig. 2B. 



Material.— Loc. 589, 4 ad. 99, 0.29-0.47 mm. (0.37 mm.); 2 ad. 

 cf cf, 0.38 and 0.65 mm. Loc. 590, 3 ad. cfcT, 0.27-0.39 mm. (0.34 

 mm.). Loc. 592, 1 ad. 9, 0.52 mm.; 1 ad. cf, 0.42 mm. Loc. 638, 

 5 ad. 99, 0.30-0.32 mm. (0.31 mm.); 1 ad. cT, 0.29 mm. 



