64 G. 0. SARS. CRUSTACEA. [NORW. POL. EXP. 



and the somewhat different structure of the posterior maxillipeds. In these 

 characters, I find that a Norwegian Calanoid, long ago recorded by Boeck as 

 Euchceta armata, perfectly agrees. This form, which is still very imperfectly 

 known, also occurred rather plentifully in the samples taken during the Nansen 

 Expedition, and in addition to it, 2 well-marked new species were found, un- 

 doubtedly belonging to the same genus, though differing in the presence of 

 a very small but distinct rostral prominence. All these 3 species will be 

 described below, figures of them being given in the accompanying plates. 



9. Chiridius armatus (Boeck). 

 (PI. XVII). 



Euchceta armata, A. Boeck, Nye Slaegter og Arter af Saltvandscopepoder. 

 Chr. Vid. Selsk. Forh. f. 1872, p. 39. 



Specific Characters. Body moderately slender, with the tail almost half 

 the length of the anterior division. Rostral projection quite obsolete. Last 

 segment of trunk with the lateral corners gradually narrowed to acute pro- 

 cesses pointing slightly outwards. Caudal rami rather longer than they are 

 broad. Anterior antennae slightly exceeding in length the anterior division of 

 the body, and very slender, 24-articulate. Posterior antennas with the inner 

 ramus rather short and thick, scarcely more than half as long as the outer. 

 Mandibular palps with the inner ramus very poorly developed. Oral parts in 

 male much reduced. 1st pair of natatory legs with the outer ramus distinctly 

 3-articulate, 1st joint carrying the usual spine outside. Inner ramus of 1st 

 and 2nd pairs uniarticulate, that of 3rd and 4th pairs 3-articulate. Legs of 

 last pair in male rather feeble, and simple, styliform. Length of adult female 

 4'30 mm., of male 3'30 mm. 



Remarks. This form, as above stated, was first recorded by the late 

 A. Boeck as a species of the genus Euchceta. It was, however, like the 

 other forms recorded by him, very imperfectly characterized, and no figures 

 were given. For this reason, its true relationship to other forms was not 

 recognized by Dr. Giesbrecht, who places it among other doubtful species, the 

 genus of which could not be determined. There cannot, however, be any 

 doubt, that Boeck's species is congeneric with that described by Dr. Gies- 



