90 BEIT1SH COPEPODA. 



Genus 1. OITHONA, Baird (1843). 



(Zoologist, 1843.) 



Body mucli like that of Cyclops, but greatly atten- 

 uated. Head quite distinct from thorax. First pair 

 of antenna (PI. XIV, fig. 2) much elongated, and, in 

 the male, adapted on both sides for clasping : second 

 pair (fig. 3) 4-jointed and destitute of any secondary 

 branch. Mandible-palp (fig. 4) elongated, slender, 

 bearing two stout dentated apical spines and a jointed 

 secondary branch, together with a ciliated wart-like 

 marginal process. Maxillas stout, having a short 

 2-branched palp. First pair of foot-jaws (fig. 6) 

 long and slender (somewhat like those of Calanus) ; 

 second pair (fig. 7) also as in Calanus, but the terminal 

 portion is indistinctly jointed. First four pairs of feet 

 (fig. 8) 2-branched, all the branches 3-jointed. Last 

 pair of feet rudimentary, bearing two small setiferous 

 papillae. 



1. OITHONA SPINIFRONS, Boeck. Plate XIV, figs. 1 9 ; 



and Plate XXIV A, figs. 1, 2. 



Oithona spinifrons, Boeck. Oversigt Norges Copepoder, p. 25 



(1864). 



? helgolandica, Glaus. Die frei-lebenden Copepoden, p. 105, 

 t. xi, figs. 1012 (1863). 



First pair of antennae about as long as the cephalo- 

 thorax, 10- (11-?) jointed, beset, especially near base and 



