84 BRITISH COPEPODA. 



2. PSEUDOCYCLOPS OBTUSATUS, Brady and Robertson. PI. 



XII, figs. 113. 



Pseudocyclops obtusatus, B. & B. Ann. and Mag. Nat. Hist., 

 ser. iv, vol. xii, p. 128, pi. viii, figs. 

 47 (1873). 



Cephalothorax very tumid, obtusely rounded in front 

 down to the rectangular and almost obsolete rostrum ; 

 dorsum strongly arched; first segment very large, 

 nearly equal in length to half the cephalothorax ; abdo- 

 men slender, in the male 5-, in the female 4- jointed. 

 Anterior antennae (figs. 2, 3) 18-jointed, stout, and 

 about equal in length to the first cephalothoracic 

 segment ; basal joints (except the first) extremely 

 short, gradually increasing in length to the terminal 

 joint, which is twice as long as broad, closely beset on 

 the anterior margin with hairs of moderate length ; 

 right antenna of the male swollen in the middle, but 

 having no true hinge-joint : posterior antennae 4-jointed 

 (fig. 4), with a large biarticulate secondary branch 

 springing from the basal joint. Mandible-palp (fig. 5) 

 large, having a uniarticulate secondary branch. First 

 four pairs of swimming feet (fig. 9) stoutly built, with 

 short setas and broad marginal lancet-shaped spines ; 

 branches subequal, triarticulate ; the setae of the inner 

 margins (fig. 12) are peculiar, consisting of short, 

 slender, abruptly truncated rods, from the extremities 

 of which spring solitary short hairs : fifth pair (fig. 



