159 



the 3rd, terminal part about half the length of the proximal one. Posterior 

 antennae with the outer rum us distinctly 3-articulate, middle joint well defined 

 and setiferous. 1st pair of legs with the outer ramus shorter than the 1st joint 

 of the inner, terminal joint about as long as the middle one, and armed with 2 

 spines and 2 geniculated seta?; inner ramus with the 1st joint very slender and 

 almost 3 times as long as the other 2 combined, last joint linear and twice as 

 long as the 2nd, tipped with a slender claw, a rather long seta, and a hair-like 

 bristle. Natatory legs about as in A. imus. Last pair of legs also of a rather 

 similar appearance, the distal joint being narrow oblong in form, but with 3 

 instead of 2 setae outside; inner expansion of proximal joint comparatively short, 

 triangular, extending scarcely beyond the middle of the distal joint. Ovisacs of 

 moderate size and somewhat more divergent than in A. nun*. 



Male with the 2nd basal joint of the 1st pair of legs produced inside to 

 3 blunt spiniform projections. Inner ramus of 2nd pair of legs resembling in 

 structure that in the male of A. imus. Last pair of legs likewise of a very 

 similar appearance. 



Colour whitish, with a faint yellowish tinge. 



Length of adult female 0.57 mm. 



Remarks. This species is closely allied to A. imus, but is of smaller 

 size and less slender form of body. It moreover differs somewhat in the structure 

 of the 1st and last pairs of legs. 



Occurrence. Some few specimens of this form were found last summer 

 off the south coast of Norway, at Ris0r and Lillesand. 



101. Amphiaseus longirostris (Glaus). 



(PI. & CI). 

 Y Dactylopus longirostris, Glaus, Die freilebenden Copepodeu, p. 127, PI. XVIII, li^s. 4 6. 



Syn : Diosaccus longirostris, Boeck. 

 Dactylopus longirostris, var. arctica, Scott. 



Specific Characters. Female. Body moderately robust and slightly at- 

 tenuated behind. Cephalic segment comparatively large and deep, rostrum rather 

 prominent and evenly curved, terminating in an acute point. Urosome shorter 

 than the anterior division, with the hind edge of the segments finely spinulose 

 ventrally and laterally. Caudal rami quadrangular, being about as long as they 

 are broad, innermost but one of the apical seta? exhibiting near the base a con- 

 spicuous bulging outside, overlapping the adjacent seta; spine of outer corner 



