ferous appendage attached outside the basal part at some distance from its end, 

 outer ramus well developed and abruptly reflexed, being composed of 3 4 joints 

 carrying long plumose setse. Maxillae with the masticatory lobe well defined and 

 carrying a number of sharp claw-like spines accompanied inside by a thick seti- 

 form appendage, palp lamellar, with the outer distal lobe very small, proximal 

 lobe well developed, recurved, and provided at the tip with long plumose setse 1 ). 

 Both pairs of maxillipecls slender and elongated, the anterior ones 5-articuiate, 

 the posterior ones 4-articulate, both carrying long anteriorly-curving spines. Na- 

 tatory legs with no distinctly developed seta inside the 1st joint of the outer 

 ramus, apical spine of this ramus very slender and serrate outside, spines of 

 outer edge more perfectly developed in male than in female. Last pair of legs 

 represented by a small conical joint terminating in a long seta; another similar 

 seta issuing from a knob-like prominence on each side of the segment itself, 

 seems to answer to that arising from the basal joint of these legs in other Cyclo- 

 poida. Caudal rami in female strongly divergent, with the 2 middle apical setse 

 much elongated and crossing each other at the base; those in male of quite 

 normal appearance. 



Remarks. The present genus was established in the year 1843 by Baird, 

 to include a species, 0. plumifera, taken in the tropical part of the Atlantic. 

 Another genus with the same name has been established by Alder and Hancock 

 for a nudibranchiate Mollusc; but as this genus is of younger date than that 

 of Baird, its name must be changed. The genus Scribella of Dana is identical 

 with that of Baird, and likewise of later date. Several species of this genus 

 have in recent times been described from different parts of the Oceans. Thus 

 Dr. Giesbrecht records no less than 8 species, and some additional species have 

 been named by other authors. There is, however, still considerable confusion 

 about the right identification of some of these species, partly owing to their 

 close relation and partly to the difficulty which is connected with an exact ana- 

 tomical examination of such delicate and fragile animals. One of the species 

 described by Dr. Giesbrecht, 0. nana, seems in some respects to differ more 

 conspicuously from the others, and may perhaps be regarded as the type of a 

 separate, though nearly allied genus, for which the name Oithonina may be 

 proposed. To the fauna of Norway belong 2 well-defined species, to be de- 

 scribed below. 



1 ) I have formerly described these 2 lobes as the exopodal and epipodal lobes, but find 

 that these names cannot properly be retained, since they unquestionably, as is clearly seen in the 

 present genus, answer to the inner and outer rami of the mandibular palp. As, however, both 

 these lobes are always attached outside the palp, I find it more appropriate to give them the 

 indifferent names of proximal and distal outer lobes. 



