161 



102. Amphiaseus tenuiremis (Brady). 



(PI. Oil). 

 Dactylopus tenuiremis, Brady, Monogr. Brit. Copepoda, p. 115, PL LVI, figs. 12 18. 



Specific Characters. Female. Body comparatively short and stout, some- 

 what depressed in front, and slightly attenuated behind. Rostrum rather large, 

 lanceolate. Urosome much shorter than the anterior division, anal segment not 

 quite as long as the preceding one. Caudal rami short, broader than they are 

 long, middle apical setae moderately thickened at the base. Anterior antennae 

 slender and attenuated, 8-articulate, 4th joint twice as long as the 3rd, terminal 

 part very narrow and about half the length of the proximal one. Posterior an- 

 tennae with the outer ramus distinctly 3-articulate, middle joint well defined and 

 setiferous. 1st pair of legs comparatively strongly built, outer ramus, however, 

 as usual, small, scarcely attaining half the length of the inner, and having the 3 

 joints of about equal size, the last one carrying 3 spines and 2 geniculated setae; 

 1st joint of inner ramus rather large and slightly curved, being almost 4 times 

 as long as the other 2 combined, last joint not much longer than the 2nd and 

 tipped with an unusually strong and evenly curved claw-like spine, a slender seta 

 and a very small hair-like bristle. Natatory legs rather slender, but otherwise 

 of normal structure. Last pair of legs with the distal joint narrow oblong in 

 form, tapering towards the end, and densely ciliated both outside and inside, 

 marginal setae rather unequal and 6 in number; inner expansion of proximal joint 

 triangular, extending somewhat beyond the middle of the distal joint, marginal 

 setae rather elongated. 



Male exhibiting the usual sexual differences from the female. 



Body whitish, with a more or less distinct reddish tinge. 



Length of adult female 0.63 mm. 



Remarks. This species was recorded by Messrs. Brady and Robertson as 

 early as the year 1875, and was subsequently described and figured (though rather 

 imperfectly) by the first-named author in his well-known Monograph. It is a true 

 Amphiascus, and may be easily distinguished from most other species of that 

 genus by its comparatively short and stout form, and by the structure of the 1st 

 and last pairs of legs. 



Occurrence. I have found this form in considerable abundance in several 

 places both on the south and west coasts of Norway, in depths ranging from 10 

 to 30 fathoms. It is also recorded by Mr. Scott from the Finmark coast. 



Distribution. British Isles (Brady), Arctic Ocean, off Spitsbergen and 

 Franz Josef Land (Scott). 



