COPEPODA FROM IFALUK ATOLL 131 



Rostrum, as appears from lateral view, curves downward at almost 

 square angle with rostral base, obliquely pointed (fig. 456). Cephalic 

 somite and 2nd thoracic somite on each side with 1 hair. Cephalic 

 somite with distinct median longitudinal carina, terminating poster- 

 iorly in blunt tooth, not overlapping 2nd thoracic somite. 2nd to 

 5th thoracic somites and genital complex also provided with distinct 

 carina, overlapping following somite very slightly, and rounded at 

 apex. In lateral aspect these carinae give the animal a most dis- 

 tinctive appearance. Abdomen at this stage, in addition to 5th 

 thoracic somite, composed of only two parts: genital and anal com- 

 plexes. Genital complex provided with wing-shaped prolongations, 

 directed laterocaudally. 



Furcal rami cylindrical, twice as long as broad, with 5 marginal 

 setae and 1 appendicular seta each. Seta 2 on each side lengthened 

 and thickened, reaching half length of body; remaining setae short. 

 Furcal rami reach as far as laterocaudal projections of genital com- 

 plex. 



After dissection, the antennules, antennae, mouth parts, and legs 

 proved to be very undeveloped and are not described in detail here. 

 Since I could not find a description of the copepodid stages of Pelti- 

 dium purpureum in the literature, the identification of these juvenile 

 specimens remains somewhat doubtful. It seems to me that a more 

 complete material of this fairly common species, with the object of 

 describing the developmental history, can easily be collected, with 

 the result that I have refrained from a detailed description of these 

 isolated juvenile specimens. 



P. purpureum is widely distributed in the northern temperate 

 Atlantic, on the European side, and in the Mediterranean. Details 

 of its distribution can be found in Lang (1948, pp. 431, 432). 



Peltidium intermedium A. Scott, 1909 



Figures 46a,6, 47, 48 



Peltidium intermedium A. Scott, 1909, p. 203, pi. 65 (figs. 6-10) .— Sewell, 1940, 

 pp. 143, 353, 355, 363.— Nicholls, 1941, p. 392.— Lang, 1948, p. 436, fig. 

 186 (no. 2). 



Material. — Loc. 167-D-7, 1 ad. 9, 0.77 mm. 



Description. — The following is based on the above specimen; 

 it has been dissected and the appendages mounted. 



The general shape of the body corresponds very well with A. Scott's 

 description (1909, p. 203), except for minor details in the armature. 

 Body in dorsal aspect broadly ovate, with greatest diameter at pos- 

 terior end of cephalic somite; proportion of length and diameter 

 is 23:15. Head and 1st thoracic somite completely fused to form 

 cephalic somite, which, as well as thoracic somites 2 to 5, is elevated 



