42 BRITISH COPEPODA. 



1. METRIDIA ARMATA, Boeck. PI. IT, figs. 1 12; PI. 



LVI, figs. 19, 20. 



Metridia armata, Boeck. Oversigt over de ved Norges Kyster 



iagttagne Copepoder, p. 14 (1865). 



Paracalanus hibernicus, Brady and Robertson. Annals and 

 Magazine of Nat. Hist., ser. 4, vol. xii, 

 p. 126, pi. viii, figs. 13 (1873). 



Rostrum obtuse ; anterior antennse (fig. 2) nearly 

 alike in both sexes, slender, a little longer than the 

 cephalothorax, thick at the base and tapering gradually 

 to the apex ; the nine basal joints (except the first, 

 which is very large) are broader than long, the rest 

 being from twice to thrice as long as broad except the 

 apical one, which is very short : each joint bears on 

 its outer margin one or two short setae (some of these 

 being in the male developed into thickened rod-like 

 appendages), and the seven or eight proximal joints 

 are each produced on the outer margin into a short 

 median spine or tooth; the last joint has one long and 

 two small setao, the penultimate one very long seta : in 

 the male the antenna is twenty -jointed, hinged between 

 the seventeenth and eighteenth joints (PL LVI, fig. 19). 

 Both branches of the posterior antennae are stout and 

 nearly equal in size. Mandibles (fig. 3) strong, with a 

 largely developed, biramose palp. Second pair of foot- 

 jaws (fig. 6) very slender. The swimming feet (fig. 7) 

 have the inner branch very short, only about half 

 the length of the outer branch, the last joint of which 

 is long and truncate at the apex ; marginal and 

 terminal spines very small, the latter (fig. 12) some- 



