16 



setae spiniform. Front in both sexes provided with 2 slender recurved filaments. 

 Anterior antennae in female resembling in structure those in Acartia; right 

 antenna in male conspicuously transformed and strongly hinged. Posterior 

 antennas, oral parts, and natatory legs nearly as in Acartia. Last pair of legs 

 in female comparatively large and confluent at the base, terminal joint claw- 

 like; those in male powerfully developed and very asymmetrical; right leg 

 much the larger and terminating in a slender incurved claw. Spermatophore 

 affixed to the genital segment of the female, accompanied by a thin plate 

 folding upwards on each side of the segment. 



Remarks. The name Paracartia was proposed in 1894 by Scott merely 

 to designate a sub-genus of Acartia. I think, however, that the differences 

 are greath enough to warrant this sub-genus to be raised to a true genus 

 associated with Acartia in the family Acartiidce, as defined by the present author 

 (see Vol. IV, p. 147). Scott records 2 supposed species of this genus, both found 

 together in a plankton-sample taken in the bay of Guinea; but, as suggested 

 by Giesbrecht, there can be no doubt that P, spinicaudata is the female and 

 P. dubia the male of one and the same species, to which the latter name has 

 been assigned by Giesbrecht. The Acartia laiisetosa of Kriczagin (= A. ver- 

 rucosa Thompson) is apparently referable to the present genus, though differing 

 in some particulars conspicuously from the species observed by Scott. On the 

 other hand, is the Norwegian form described below very closely allied to that 

 species. 



9. Paracartia Grani, G. O. Sars. 



(PI. X & XI). 

 Paracartia Grani, G. O. Sars, Bergens Museums Aarbog 1904, No. 4, p. 3, PI. I IV. 



Specific Characters. Female. Body comparatively slender, with the 

 anterior division gradually narrowed in front. Wing-like expansions of last 

 trunkal segment very large, triangular, each terminating in an acute point. 

 Urosome scarcely exceeding in length J /4 of the anterior division, and some- 

 what constricted in the middle; genital segment fully twice as broad as it is 

 long, forming on each side a lamellar expansion obliquely truncated at the end. 

 Caudal rami conspicuously asymmetrical, the right ramus being considerably 

 broader than the left; marginal setae comparatively short, 2 of them attached 

 to the outer edge; middle apical seta an both rami spiniform, that on right 

 ramus much stronger than that on left. Anterior antennae not fully attaining 

 the length of the anterior division of the body, and apparently composed of 

 17 or 18 joints, some of the proximal ones being however less distinctly 



