339 



Gen. 79. PsammiS, 1 ) G-. O. Sars, n. 



Body sub-cylindric in form, with no sharp demarcation between the an- 

 terior and posterior divisions, and with all the segments closely crowded together, 

 being not separated by any conspicuous constrictions. Cephalic segment produced in 

 front to a prominent rostral projection. Genital segment in female imperfectly 

 subdivided. Caudal rami of moderate size, with the apical setse unusually pro- 

 longed. Anterior antennas short and thick, hirsute, with the number of articulations 

 much reduced. Posterior antennse with the proximal joint not subdivided, outer 

 ramus well developed, tri-articulate. Mandibles strong, with the basal part of 

 the palp broad and expanded, rami, however, imperfectly developed. Maxillae 

 and maxillipeds about as in Danielssenia. Natatory legs powerfully developed, 

 with some of the setse unusually long and slender; inner ramus of 1st pair bi- 

 articulate. Last pair of legs with the distal joint confluent with the proximal one. 



Remark's, This new genus is allied to Danielssenia, though the external 

 appearance of the body more resembles that in the genus Rubertsonia. It differs 

 conspicuously from both these genera in the [structure of the mandibular palp 

 and of the last pair of legs. Moreover the extraordinary length of the caudal 

 setse and of the apical setse of the natatory legs is rather characteristic. The 

 genus only comprises as yet a single species, to be described below. 



217. Psammis longisetosa, G. 0. Sars, n. sp. 



(PI. CCXXV). 



Specific Characters. Female. Body comparatively short and compact, 

 slightly tapering behind. Cephalic segment large, exceeding in length the 4 suc- 

 ceeding segments combined, and scarcely contracted in front, rostral projection 

 well defined behind and somewhat lamellar, tip obtusely rounded. Epimeral 

 plates of the succeeding segments well defined and obtusangular behind. Last 

 pedigerous segment scarcely narrower than the preceding one. Urosome consider- 

 ably exceeding half the length of the anterior division, and having the segments 

 finely spinulose at the hind edge. Caudal rami about the length of the last 

 segment and slightly divergent, apical setse very strong and dark-coloured, the 

 inner medial one almost attaining the length of the whole body. Eye incon- 

 spicuous in preserved specimens. Anterior antenna of almost uniform width 

 throughout and somewhat curved, being composed of 4 joints only, the last one 

 representing the terminal part and carrying a number of strong plumose setse. 



No men proprium. 



