NO- 5.] ACCOUNT OF THE SPECIES. 



107 



tical with the species formerly observed off the Norwegian coast, and the 

 other is indistinguishable from a species recently described by Dr. Giesbrecht 

 from great depths of the Pacific Ocean. The latter species will be described 

 more in detail below. It may be here noted, that a species of this genus 

 has been recorded (1875) by Prof. LiUjeborg from Mossel Bay in Spitsbergen, 

 and by Mr. Bourne (1885) from Plymouth, in both cases determined as 

 0. mediterranea, Glaus. 



24. Onccea notopus, Giesbrecht. 



(PI. XXXII, figs. 1-14). 



Oncma notopus, Giesbrecht, Fauna und Flora des Golfes von Neapel: Pela- 



gische Gopepoden, p. 600, etc., PI. 47, figs. 12, 15, 45. 



Specific Characters. Body comparatively robust, with the anterior divi- 

 sion rather tumid, oblong oval in form, greatest width about equalling half 

 the length, and occurring in front of the middle, anterior extremity narrowly 

 rounded. Tail not attaining half the length of the anterior division, genital 

 segment longer than the remaining part. Gaudal rami short, not nearly twice 

 as long as they are broad, innermost apical seta longer than the outermost. 

 Anterior antennae with the proximal joints rather broad and compressed, 3rd 

 joint about the length of the 2 preceding ones combined. Posterior antennae 

 with the terminal joint comparatively short, scarcely more than half the length 

 of the penultimate one, and having the 2 groups of anteriorly-curving setae 

 close together. Posterior maxillipeds comparatively strong, dactylus shorter 

 than the palm, and coarsely denticulate inside, the 2 palmar spines likewise 

 spinulose and rather strong. Last pair of legs forming each a slender cylin- 

 dric piece, carrying 2 subequal spines on the tip, and extended obliquely up- 

 wards. Length of adult female 0'70 mm. 



Remarks. Neither in the 3 figures given by Dr. Giesbrecht (body of 

 female in outline, seen from the side and from above, and the left posterior 

 maxilliped), nor in his descriptive notes, can I find any point of difference 

 whatever between his species 0. notopus and the polar form here in 

 question, and I am therefore induced to believe that these two forms are in 

 fact identical, in spite of their widely remote occurrence. The most conspic- 

 uous specific character is undoubtedly the peculiar structure of the last pair 

 of legs, which is exactly the same in the 2 forms. 



