NO. 5,] ACCOUNT OF THE SPECIES. 45 



of about equal length, both issuing close together from the end of the basal 

 part, and curving inwards. The 3 joints of the outer ramus gradually diminish 

 in size, the last being rather small and lamelliform, with several small spines 

 inside, and 2 somewhat longer setae at the tip. The inner ramus terminates 

 in a hook-shaped point. In the left leg, the 2nd basal joint is quite short and 

 of irregular form, encompassing the end of the 1st basal joint of the right leg. 

 The 2 rami are of very unequal length, and issue far apart, the outer one 

 bsing twice as long as the inner, and having the 1st joint longer than the 

 other 2 combined. This joint originates with a broad base, but rapidly con- 

 tracts, and projects at the end inside to a small linguiform lobe, its 2 outer 

 joints being very narrow and quite smooth. The inner ramus is simple styli- 

 form, terminating in an acute point. 



The musculature of the body is much stronger than in the female, and 

 the movements of the animal must therefore be assumed to have been rather 

 more powei-ful. The muscles converging from the dorsal face to the posterior 

 antennae and mandibular palps are especially conspicuous, exhibiting a peculiar 

 opalescent lustre; and the muscles acting upon the tail are also unusually 

 strong. 



Occurrence. It is very strange that this large and conspicuous Calanoid 

 has hitherto quite escaped the attention of zoologists, though it seems to be 

 one of the commonest forms of the Polar Sea. Indeed, it occurred rather 

 plentifully in the greater number (15) of the samples taken during the 'Fram' 

 Expedition. It was collected both at the surface, and down to 300 metres, 

 and seems to be as common in the western, as in the eastern part of 

 the basin traversed. Young males occurred in almost the same number as 

 females; but of fully adult, sexually mature males only a very limited 

 number of specimens was found. 



Gen. Scolecithrix, Brady. 

 Remarks. This genus was established in the year 1883 by Prof. Brady, 

 to include the form previously described by Lubbock as Undina Dance; 

 at the same time he adds another species, S. minor, which, like the former, 

 was procured during the Challenger Expedition, and which also occasionally 

 occurs off the coast of Norway. Dr. Giesbrecht, too, enumerates no less than 



