21 



Feb. 23th, 1897; between Baro and Lodingen; 0200 m. 



9 6.5 mm., 6.6 mm., 6.6 mm. 

 Feb. 24th, 1897; at the mouth of the Tjeldsund; 0200 m. 



9 6.0 mm., 6.5 mm., 7.0 mm. 

 April 10th, 1897; at Balstad in Lofoten; 0200 m. 



9 6.5 mm., 6.8 mm. 



June 25th, 1897; 15 geogr. miles NE. of Jan Mayn; m. 

 9 6.8 mm., 8.2 mm., 8.5 mm., 9.2 mm., 9.3 mm. 

 Finally I have observed c. hyperboreus from the deep of the 

 fjords near Bergen, namely in plancton samples from the Herlo- 

 fjord (Feb. 28th, and March 15tb, 1898; 0450 m.). The spe- 

 cimens were females, length 6.5 mm. The largest female individuals 

 from the Norwegian coast have thus been about 7 mm., while the 

 largest from the Arctic Sea measured over 9 mm. 



C. hyperboreus $ (new). 



Notwithstanding that in recent years a considerable quantity 

 of plancton material from the arctic waters has been examined, 

 nobody has observed the male of c. hyperbweus. I was therefore 

 surprised to find, in the sample from Feb. 23th, 1897 (between 

 Baro and Lodingen; 200 m.), a couple of male calanus, which 

 I at once thought were too large to be the males of c. finmarchicus. 

 By the preliminary examination I was soon disappointed by finding 

 that the lateral corners of the last body-segment were rounded, 

 thinking that the male c. hyperboreus must have pointed corners 

 like the female. However, it was of course no necessary supposi- 

 tion, and after having investigated the matter more closely, I ven- 

 ture to say with certainty that it really were males of c. hyper- 

 boreus that I had before me. 



Just as the females of the two species resemble one another 

 very much, so it is the same with the males. A careful examina- 

 tion of the fifth pair of feet, however, may decide to which species 

 a specimen belongs. Both males of c. hyperboreus that have been 

 found have a total length that exceeds the maximum limit for at 

 any rate the males of c. finmarchicus, and in our waters no females 

 of the latter occur that can equal in length the said males. 



Feb. 23th- 1897; between Baro and Lodingen; 200 m. 



C. hyperboreus cf front part of the body 4.3 mm. 1 



I 5.5 mm. 



- hind - - 1.2 J 



- front - - 3.6 ) 



- hind - - 1.2 J ' 



In the segmentation of the body (fig. 18), or in the structure 

 of the anterior antennae I have not been able to find any obvious 

 difference between the two closely connected male calani. . The 

 appendices of the antennae had mostly fallen off, but the remainders 

 suggested the same form and the same reciprocal arrangement as 

 in c. finmarchicus. Even in the structure of the 2nd pair of 

 maxillipeds I have found no essential difference. However, an 

 examination of the first basal joint will leave no doubt as to the 

 species ; for in the male c. finmarchicus the row of teeth goes quite 

 to the edge of the joint or to the boundary between first and second 

 basal joints (fig. 17); in hyperboreus, on the contrary, the row of 



teeth does not reach quite down to edge of the joint (fig. 29, 31). 

 Besides, in the former the row of teeth makes a greater curve 

 than in the latter, in which it comes very near to a straight line 

 (fig. 16, 30). The inner edge of first basal joint is quite straight in 

 hyperb., but concave in finm. The left foot in fifth pair of feet 

 seems also to be somewhat different in the two species. In finm. 

 y2 is longer than y s , while in hyperb. it is shorter. The joint y s 

 further has a somewhat different appearance, the joint narrowing 

 very much towards the end in the former, while in the latter it is 

 nearly equally broad throughout its length. 



In the female of the two calanides the structure is the same 

 as in the male, as for the arrangement of the teeth on the inner 

 basal joint of the fifth pair of feet (fig. 27, 28). The occurring diffe- 

 rence has first been noticed by Mr. GTIESBRECTH. While equally- 

 sized females as a rule can be easily distinguished without examning 

 the fifth pair of feet, it is probably necessary, in order to disting- 

 uish the males, to cut out the fifth pair of feet. The size will 

 of course be suggestive of the species. The largest specimens of 

 c. finmarchicus cT that I have hitherto found, measured 3.6 mm., 

 and this size is not likely to be exceeded. Another hint to faci- 

 litate distinction is likely to be obtained from the form of the front 

 part of the body. In c. hyperboreus cf it is, as it were, cut straight 

 off (fig. 17), while it has been more pointed in the males I have 

 seen of the other form. Thus it has also been drawn by Mr. BEADY 

 in report of the copepoda collected by H. M. S. Challenger, pi. 1 , 

 fig. 1. It may be worth noticing that the two males of c. hyper- 

 boreus were observed at winter-time. In samples from the Arctic 

 Sea (summer 1897) I have seen females of hyperboreus by the 

 hundred, but not a single male. 



Paracalanus parvus, Glaus. 



In my tables this species is insufficiently represented, as for 

 some time I did not distinguish it from pseudocalanus elongatus. 

 Professor SABS*) mentions it among the species that serve as food 

 for the sprat. 



Pseudocalanus elongatus, Boeck. 



The species is mentioned by Mr. BOECK both from the Kri- 

 stiania-fjord and from the West-coast of Norway. It is one of the 

 few species that occur in the winter plancton in Lofoten, where for 

 instance it was found in great quantity under the ice in the Trold- 

 fjord. The most northerly place where I have hitherto observed 

 the species is the Tromsosund, but no doubt it goes a good deal 

 farther to the North. 



Undinopsis bradyi, G. 0. Sars. 



In "Unders0gelser over Dyrelivet i Arktiske Fjorde", Mr. SPAEKE 

 SCHNEIDER has mentioned a copepod that is called wncZiwqpsis bradyi, 



*) G. 0. SAKS, Brislingen og Brislingflsket. 



