NO. 5.] ACCOUNT OF THE SPECIES. 99 



Fam. TEMORID.E. 



Gen. Metridia, Boeck. 



Remarks. This genus, established in the year 1864 by Boeck, is very 

 nearly allied to Pleuromma of Glaus, the chief difference being the absence 

 of the lateral eye (luminous organ?). Boeck records 2 species of this genus 

 from the Norwegian coast, viz., M. armata and M. lucens; but both these 

 forms w^ere very insufficiently characterised. The first-named species has 

 subsequently been identified by Dr. Giesbrecht w^ith Calanus longus of Lub- 

 bock, whereas the 2nd species has not been recognized. I believe, however, 

 that it is the same species as that subsequently described by Brady and 

 Robertson as M. hibernica. To these 2 species Dr. Giesbrecht has added 

 6 new species, one from the Faroe channel, the others from the tropical parts 

 of the oceans. In the samples brought home from the Nansen Expedition, 

 one species of this genus occurred in great abundance. 



21. Metridia longa (Lubbock). 

 (PI. XXIX). 



Syn: Metridia armata, Boeck. 



Remarks. I think that Dr. Giesbrecht is quite right in identifying 

 Boeck's species with Calanus longus of Lubbock, and as the specific name 

 proposed by Lubbock is the older one, the species ought hereafter to be 

 termed as above. The occurrence of this form in the Arctic Ocean has been 

 already stated by several authors, and the species may therefore be suffi- 

 ciently well known, for which reason I think any detailed description of it 

 can be dispensed with. As, however, no good illustrations of it exist, I give 

 on the accompanying plate exact figures of both sexes, together with some 

 details, all figures drawn from specimens procured during the Nansen Expe- 

 dition. The average length of adult females is 4*30 mm., or about the same 

 as that of Norwegian specimens. 



Occurrence. This form occurred rather abundantly in the greater number 

 of the samples (14), and was taken both from the surface of the sea and 

 down to a depth of 300 metres. 



Distribution. Coast of Norway, very abundant in the great depths of 

 the fjords, below 100 fathoms, Arctic Ocean, Spitsbergen, the Kara Sea. 



