COPEPODS OF THE WOODS HOLE REGION 



405 



than the branches, the latter U-shaped; two middle terminal claws 

 of the first leg branched; fourth leg 3-segmented, with five spines 

 and no seta. Total length, 5-6.5 mm. 



Male. — Unknown. 



Remarks. — This species may be identified by the peculiar chela 

 on the maxillipeds, which is the only instance of its kind in this 

 genus. The swordfish is its chief host, and if these could be exam- 

 ined when first taken out of the water they would probably yield 

 specimens of this parasite. 



CALIGUS BELONES Kr0yer 



FiGUEE 252 



Caligus helones Kb0yeb, Naturh. Tidsskrift, ser. 3, vol. 2, p. 81, pi. 7, 1863. — 

 Wilson, Proc. U. S. Nat. Mus., vol. 28, p. 586, pi. 12, 1905. 



Occurrence. — Two females were found on the outside surface of a 

 small dolphin near Woods Hole. 



Distribution. — Denmark (Kr0yer) ; Norway and Sweden (01s- 

 son) ; Woods Hole (Wilson). 



Color. — The preserved material is of a light yellowish brown 

 without any traces of pigment markings. 



FcTnale. — Carapace about half the 

 entire length; lunules large, circular, 

 and not projecting; fourth segment 

 two-thirds as wide as genital segment, 

 much narrowed where it joins the 

 third segment; genital segment half 

 the width of the carapace, emarginate 

 posteriorly, without leg rudiments. 

 Abdomen 1-segmented, twice as long 

 as wide, with convex lateral margins; 

 caudal rami short and wide; furca 

 shaped like a tuning fork; fourth leg 

 3-segmented, with four spines and no 

 seta. Total length, 4.75- mm. 



Male. — Carapace less than half the entire length; genital segment 

 circular in outline, as wide as long, with leg rudiments at its posterior 

 corners. Abdomen as long as genital segment, 2-segmented, the 

 terminal segment twice the length of the basal; caudal rami nar- 

 rowed distally ; fourth legs reaching the anal segment. Total length, 

 4r-5 mm. 



Remarks. — This species can be identified by the shape of the furca 

 and by the fact that the fourth legs have but four spines and 

 no seta. 



Figure 252. — Caligus belones: a. Fe- 

 male, dorsal ; b, female, fourth leg 



