208 



referable to this genus, the one, P. parvula, from the west coast of Ireland, 

 the other, P. pulla, from the Indian Ocean. The first-named species also 

 occurs off the Norvegian coast, and will be described below. 



Paroithona parvula, Farran. 



(PI. CXIV). 



Paroithona parvula, Farran, Second Report on the Copepoda of the Irish Atlantic Slope. 

 Fisheries Ireland. Scicnt. Investig. 1906, II, p. 89, PI. X, figs. 1 13. 



Specific Characters. Female. Body moderately slender, with the 

 anterior division regularly oval fusiform in outline, greatest width equalling 

 about half the length and occurring a little in front of the middle; frontal 

 part obtusely blunted and evenly rounded below, without the slightest trace 

 of any rostrum. Tail exceeding somewhat half the lenght of the anterior 

 division, and very narrow, cylindrical in form; genital segment only slightly 

 dilated in its anterior part and longer than the 2 succeeding segments com- 

 bined; anal segment fully as long as the preceding one and slightly widening 

 distally. Caudal rami quite short, not nearly attaining the length of the anal 

 segment, and slightly divergent; seta of outer edge attached near the base; 

 apical setae very unequal, 2 of them excessively prolonged and crossing each 

 other at the base. All integuments very thin and fragile. Anterior antennae 

 not attaining the length of the anterior division, and composed of 9 joints clothed 

 with partly very long and diverging setae; some of the joints being however 

 less perfectly defined. Posterior antennae biarticulate, proximal joint nearly 

 twice as long as the distal one. Mandibular palp armed at the inner pro- 

 jecting corner with a single strong claw-like spine clothed on both edges with 

 a limited number of slender spikes; inner ramus very small, outer well developed, 

 imperfectly 3-articulate, and provided with 5 long densely plumous setae. Max- 

 illae and maxillipeds of a structure very similar to that in Oithona. Natatory 

 legs rather slender and partly extending laterally; inner ramus in 1st pair about 

 the size of the outer, in the other 3 pairs much smaller; outer ramus in all 

 the pairs distinctly 3-articulate, its terminal joint having outside in the 2 an- 

 terior pairs 2 spines, in the 2 posterior pairs a single spine; apical spine of 

 this ramus in the 3 posterior pairs exceedingly long and slender. Last pair 

 of legs apparently represented on each side by a single short seta arising from 

 a knob-like prominence. 



Colour not yet ascertained. 



Length of adult female 0.52 mm. 



Male unknown. 



