124 



lipecls more robust, with the terminal part reflexed. The 4 anterior pairs of legs 

 comparatively short and compact, with both rami triarticulate and less unequal 

 than in the Heterorhabdidce. Last pair of legs not natatory in either of the sexes, 

 inner ramus rudimentary or quite wanting. 



Remarks. The type of this new family is the genus Arietellm of Gies- 

 brecht, which was referred by that author to his subfamily Heterochcetince, 

 though in some respects, and more especially in the structure of the last pair of 

 legs, it differs very materially from the 3 genera now included in the family 

 Heterorhabdidce. On the other hand, it exhibits a close relationship to the genus 

 Paramisophria of Scott, as also to another new genus, Seottula, to be described 

 below, these 3 genera accordingly forming together a natural group or family. 

 The chief distinctive character of this family, as compared with the Heterorhabdidce, 

 is the very different structure of the last pair of legs, these in the latter family being 

 natatory like the preceding ones, whereas in the present family they are much 

 reduced in size, and not at all natatory in either of the sexes. This is appar- 

 ently a character of fundamental importance, and has for this reason been taken 

 into consideration in the distinction of several other Calanoid families. Another 

 peculiar feature characteristic of the present family, is the inequality of the 

 anterior antenna} in both sexes, the left one being the longer. This inequality 

 is especially conspicuous in the genus Scot hi It/, and is also present, though in a 

 less conspicuous manner, in the genus Paramisophria. In the typical genus 

 Arietellus, it is true, no mention of such an inequality has been made; but, 

 taking into consideration the near relationship of this genus to Paramisophria, 

 it seems to me very probable that this character has been overlooked, as it 

 actually was previously in the case of Pm-<iit/ixuj>liri<i. Of the 3 genera at present 

 comprised within the family ArictcH/ike, 2 are represented in the fauna of Norway, 

 and will be treated of below. 



Gen. 22. SCOttula, G. 0. Sars, 11. 



Generic Clninn-tcr^. Body quite calanoid in appearance, with the anterior 

 division moderately tumefied; front considerably produced below, and carrying 2 

 straight tentacular appendages. Last segment of metasome simple, without any 

 subdorsal projections. Urosome moderately slender, with the genital segment in 

 female comparatively short. Caudal rami with 3 of the setse much elongated, 



