362 



Mandibles with the masticatory part quite rudimentary, palp, however, rather 

 large, with the basal part narrow and prolonged, both rami sub-terminal and 

 having the appearance of long falciform setae. Maxillae with the masticatory 

 lobe imperfectly developed, palp lamellar and- edged with numerous slender plumose 

 setse. Anterior maxillipeds somewhat resembling in structure those in the genus 

 Pseudobradya. Posterior maxillipeds very small, with the terminal joint imper- 

 fectly defined. Natatory legs of normal structure. Last pair of legs comparatively 

 small, but with very long and slender marginal setae. 



Remarks. This new genus is chiefly characterised by the very prom- 

 inent hyaline rostral plate, and by the structure of the antennae and oral parts, 

 the latter especially being rather peculiar. It comprises as yet only a single 

 species to be described below. 



Ectinosomella nitidula, G. 0. Sars, n. sp. 



(Suppl. PI. 7). 



Specific Characters. Female. Body moderately slender and somewhat 

 compressed in its anterior parts, being of nearly equal width throughout. Surface 

 of body remarkably smooth and shining. Cephalic segment large and deep, 

 considerably exceeding in length the 4 succeeding segments combined, rostral 

 plate prominent, very thin, narrow linguiform in shape, and slightly cur- 

 ved at the end. Epimeral plates of this and the 3 succeeding segments thin 

 and pellucid, including between them the oral parts and the bases of the nata- 

 tory legs. Urosome much shorter than the anterior division, and without any 

 spinules at the hind edges of the segments. Caudal rami rather far apart and 

 only slightly longer than they are broad, tip transversely truncated, apical setse 

 very slender. Anterior antennse comparatively narrow and densely clothed with 

 bristles in their outer part, basal joint occupying half the length of the antenna, 

 terminal part short, 3-articulate. Posterior antennse with 7 rather unequal spini- 

 form setse issuing from the truncated end of the terminal joint, outer ramus 

 scarcely exceeding the middle joint in length, and carrying 5 comparatively short 

 setse. Mandibular palp with the basal part long and narrow, carrying in front 

 3 curved setse, both rarai of a similar appearance, though a little unequal in length, 

 and issuing close together from the end of the basal part, each consisting of a 

 narrow cylindrical scape split up at the end into 2 or 3 slender setse. Posterior 

 maxillipeds with 3 slender apical setae gradually increasing in length inwards. 

 Natatory legs with the rami subequal in length, middle joint of inner ramus in 

 the 2nd and 3rd pairs provided inside with 2 setae Last pair of legs with the 





