46 G. 0. SARS. CRUSTACEA. [norw. POL. EXP. 



12 additional species, some from the Mediterranean, some from the tropical 

 parts of the Atlantic and Pacific Oceans. It is, however, rather questionable, 

 if all these species are in reality congeneric. The chief character upon which 

 Brady founded this genus, is the peculiar transformation of the apical setae 

 of the anterior maxillipeds into dehcate, vermiform, sensory appendages; but 

 as shown by Dr. Giesbrecht, this character is also found in some other 

 genera (Xanthocalanus, Phaenna), comprised by him in his subfamily 

 Scolecithricince ; and in the polar genus Scaphocalanus, described above, this 

 character is also rather obvious. At any rate, the Undina Dance of Lubbock 

 ought to be regarded as the type of the genus Scolecithrix, and, indeed, 

 this form is found to differ in some points very essentially from the other 

 species. Thus, the 5th pair of legs are quite wanting in the female of this 

 species, and the structure of the anterior antennae and the tail is also rather 

 different. Perhaps therefore the genus Scolecithrix should more properly be 

 restricted to this form, and the other species be referred to one or two 

 nearly-allied genera. 



In the samples taken during the Nansen Expedition, I have found some 

 few specimens of a form which must certainly be referred to this genus in 

 the sense in which Dr. Giesbrecht takes it, but which differs very materially 

 from the type species. 



4. Scolecithrix hrevicornis n. sp. 

 (PI. X). 

 Specific Characters. 2 Anterior division of body regularly oblong oval 

 in form, fi'ont evenly rounded and less deep than in the other species; last 

 segment imperfectly defined from the penultimate one, and having the lateral 

 parts obtusely produced behind. Tail scarcely more than Vs as long as the 

 anterior division, and rather narrow, caudal rami about twice as long as they are 

 broad. Anterior antennae comparatively short, not nearly attaining the length 

 of the anterior division of the body, and composed of 22 articulations, 2nd 

 and 8th larger than the others, the last two united. Posterior antennae 

 with the rami subequal in length. Anterior maxillipeds with 5 very large 

 and curved sensory appendages at the tip. Posterior maxillipeds with the 

 terminal part recurved. Last pair of legs very small, but distinct, biarticulate, 

 distal joint fusiform, with 3 unequal spines, one apical, one very small out- 



