12 



especially along the ventral side. Length of adult female but little exceeding 3 mm., 

 of male 2.80 mm. 



Remarks. As above stated, this form has generally been confounded with 

 C. finmarchicus, to which species it certainly bears a very close resemblance. It 

 is, however, rather inferior in size, and, on a closer examination, may moreover 

 be easily distinguished by the somewhat more slender form of the body, the more 

 produced and narrowly rounded frontal part, the shorter caudal rami, and the 

 considerably more elongated outer ramus on the left leg of the last pair in the male. 

 The Cetochilus helgolandicus of Glaus is unquestionably this species, and this is 

 also certainly the case with the form recorded by Brady from the Challenger 

 Expedition, and with that described by Dr. Giesbrecht from the Mediterranean. 



Occurrence. I have met with this species very frequently in the Christi- 

 ania Fjord, for instance at Dr0bak, as also in several other places on the southern 

 coast of Norway. I have no certain evidence of its occurrence farther north, 

 though in all probability it also extends for some distance along the western coast. 



Distribution. Its range is evidently a more southern one than that of 

 C. finmarchicus. It has been recorded from Heligoland by Glaus, from the British 

 Isles by Brady, the western coast of France by Dr. Canu, the Mediterranean by 

 Dr. Giesbrecht, the Black Sea by W. Karawaien, and it is even said by Brady 

 to occur in the Southern Ocean, off New Zealand, though in this case a confusion 

 with a nearly allied species may perhaps be presumed to have taken place. 



3. Calanus hyperboreus, Kr0yer. 



(PI. v.) 



Calanus hyperboreus, Kroyer, Gr0nlands Amphipoder, p. 84, PI. IV, fig. 23. 

 Syn: Calanus magnus, Lubbock. 



finmarchicus, vai\ major, auctorum. 



Specific Characters. Female. Anterior division of body very large, seen 

 dorsally oblong fusiform, greatest width about equalling Vs of the length, and 

 occurring in the middle, frontal part but slightly prominent and, seen laterally, 

 evenly rounded. Lateral corners of last pedigerous segment somewhat produced, 

 forming at the tip an acute angle. Urosome not nearly attaining half the length 

 of the metasome, caudal rami comparatively short, scarcely longer than the anal 

 segment. Anterior antennae, when reflexed, reaching beyond the caudal rami by 

 about the last 3 articulations. Male resembling that of the 2 preceding species, 

 but having the frontal part less prominent, and the lateral corners of last pedige- 

 rous segment angularly produced, as in female. Last pair of legs but slightly 

 asymmetrical, outer ramus of left leg scarcely longer than that of the right, though 



