COPEPODA 



31 



1900. Calaiius hyperboreus Kroyer, G. O Sars, p. 2. 



1901. 



1902. 

 1902. 

 1903- 



1903. 



1903. 

 1904. 



Th. and A. Scott, pp. 



338—339- 

 Th. Scott, p. 450. 

 Mrazek, pp. 506 — 507. 

 Jensen, Johansen, Le- 



vinsen, p. 303. 

 G. O. Sars, pp. 12 — 13, 



pi. V. 

 Norman, p. 135. 

 Wolfenclen, pp. 112. 



1905. Calanus hyperboreus Kroyer, Th. Scott, p. 221. 

 1905. — — — G. O. Sars, p. i. 



1907. — — — Damas & Koefoed, pp. 



352— 35S, 405. 



1908. — — — Farran, p, 20. 



1908. — — — V. Bremen, pp. 8—9, 



fig- 3- 

 1911. — — — Farran, pp. 89—90. 



1913. — — — Stephensen, p. 71. 



1913. — — — Stephensen, pp. 307 — 



30S. 



Description. f$. Size varies from 7-5 — 9 mm. 



The number of secretory pores differs from that of Calanus finmarc'nicjis by the presence of 

 a "secretory pore", (not in all specimens, as far as I was able to find out) laterally a little removed 

 from the base in Re III pes II in stead of corresponding to the wanting Se I; in pes III — IV the 

 pore was found at the same place as in Cal. finmarchiciis, but was more distinct. 



In the serration of the second basipodite of pes V it is, as shown by Giesbrecht (taf. 8 fig. 21, 23), 

 distinctly different from that of Cal.firimarcliictis^ in which species a serrated lamina is found; in Cal. 

 hyperboreus the number of teeth are smaller (abotit 25 — 35) and they ar not fused basally. 



As far as the shape of the labrum etc. is concerned I refer partly to the description of the 

 preceding species; only a few minor differences are dealt with here. The anterior process of the labrum is 

 more produced (text-fig. 6 a (d)). In the longitudinal series on the 

 oral surface (figs, i a — b) the two first groups are seen to be fused and 

 are diverging towards the free margin. In front of the lamina 

 labialis no granulation was observed. 



Behind the lamina labialis (fig. i c) and between the serrtila 

 bidentata a dense group of hairs, medially more like short spines is 

 found; the arrangement is, as seen in the figure, somewhat different from 

 that of Cal. finmarchicus G. Behind, the group is separated into 

 two, of which the inner is continued between the lobi labiales, while 

 the outer is continued on the anterior surface of the lobe and thus 

 fused with the inner series of the lobes. The labial lobes (fig. i d), 

 bear 4 — 5 longitudinal series, of which the inner is the longest and 

 has the longest hairs; behind they are more or less fused with the 

 group between the lobes. Behind the transverse list, between the 

 mandibular and the maxillular somites, laterally on each side are found two groups of hairs, forming 

 together a semicircular figure. Between these groups, in the middle, a group, which is in front triangularly 

 pointed and behind the transverse line, which probably indicates the limitation between the maxillar 

 and maxillular somites, is widened out and divided into two portions, between which a triangular 

 median group of dense hairs is found. More posteriorly a square group of densely placed short setae is 

 found in addition to one of fewer hairs just in front of the hinder limitation of the maxillar somite. 

 Laterally as seen in fig. i d a few groups are found. 



Textfig. 6 a — b. 



Calanus hyperboreus Kr. 

 6 a. Head in lateral view. X 85. 

 e. First abdominal somite. X 85. 



