ME. G. S. BRADY ON THE PELAGIC ENTOMOSTRACA. 35 



setae ; that of the male having, on the right side, a hinge joint. 

 Posterior antenna with a short, simple secondary branch. Labrum 

 large, three lobed. Anterior foot-jaws strong, with ciliated, unci- 

 form setse ; posterior foot-jaws slender, armed with setae at the 

 base ; swimming feet elongated, inner branch two-jointed. Fifth 

 pair of feet having one branch, the right of the male formed for 

 prehension. Abdomen of the male 5, of the female 3-jointed. 



1. Dias longikemis, Lillj. PI. I, fig. 14; and PL II, figs. 

 11-18. 



Bias longiremis, Lillj eborg; De Crustaceis ex ordinibus tribus 

 (1853), p. 181, T. XXIV, figs. 1-13. 

 ,, ,, Claus; Die frei lebenden Copepoden (1863), 



p. 193, T. XXXIII, figs. 6-14. 



Calanus Euchceta, Lubbock ; Ann. & Mag. Nat. Hist., 2nd 

 Series. Vol. XX (1857), p. 401. PL X, figs. 1-6. 



Body elongated, slender. Head obtusely rounded. Antenna? 

 about as long as the cephalothorax, the right of the male having 

 19, the left 21 joints. First segment of the body nearly as long 

 as the remaining four segments. Caudal segments short, about 

 once and a half or twice as long as broad. Tail seta? equal in 

 length to the abdomen, the second from the inner side being the 

 longest. Length aVth of an inch. This species may at once be 

 recognized by the peculiarity of the larger antennae which are 

 irregularly swollen at the articulations so as to give them a 

 gnarled or knotted appearance (figs. 11-13). About one half of 

 the antennal seta? are much larger than the rest, being distributed 

 at irregular intervals, but most profusely near the apex of the 

 antennae. The lower antenna (fig. 4) is two branched, the larger 

 branch three-jointed, and having on the basal joint a series of 

 eight hairs which increase regularly in length from the first to 

 the fifth or sixth. The cephalothorax has often a few minute 

 spines on the posterior border of the last segment. These are 

 variable in number : most of my specimens possess two or three, 

 but some have none. The fifth feet of the male consist each of a 

 single four or five-jointed branch, forming a pair of strong pre- 

 hensile claws (fig. 18). The fifth foot in the female (fig. 17) 



