44 



approximate halves. Anterior antennae comparatively short and rather densely 

 setiferous, consisting in female of 23 articulations. Posterior antennae with the 

 outer ramus very large, inner poorly developed, with the apical' setse much reduced 

 in number. Mandibles well developed, with the teeth of the masticatory part 

 strong and partly bidentate. Exopodite of maxillse very small, bisetose. Anterior 

 maxillipeds with all the spines of the basal part of the same structure though of 

 different length, and very flexible. Posterior maxillipeds rather powerful, with 

 the 2nd basal joint fusiformly dilated, terminal part comparatively short. Oral 

 parts in male considerably reduced. Natatory legs strongly built, inner ramus 

 with no spinules on the hind face. 5th pair of legs in female very small, with 

 the terminal joint simple, digitiform; those in male with both legs well developed. 

 Remarks. This new genus is somewhat intermediate between Phac'nna 

 and Xanthocalamis, agreeing with the former in the robust form of the body, 

 with the latter in the presence in the female of distinct, though very small legs 

 of 5th pair. From both these genera it differs very markedly in several of the 

 structural details, though in the peculiar transformation of the apical setse of the 

 anterior maxillipeds it exactly agrees with both of them. The genus at present 

 only contains a single species, to be described below. 



18. Pseudophaenna typica, G. 0. Sars, n. sp. 



(PI. XXIX, XXX). 



Specific Characters. Female. Anterior division of body, seen dorsally, 

 regularly oval or elliptical in outline, greatest width about equalling half the length, 

 anterior extremity narrowly rounded, posterior somewhat contracted. Cephalosome 

 with the dorsal margin forming a quite even curve up to the tip of the rostrum ; the 

 latter conical in form and pointing straight downwards. Last segment of metasome 

 very small, with the lateral lobes narrowly rounded. Urosome scarcely attaining 

 Ys of the length of the anterior division, genital segment about the length of the 

 2 middle segments combined. Caudal ranii a little longer than they are broad, 

 and scarcely at all divergent, innermost but one of the apical setce longer than 

 the others. Anterior antennse scarcely longer than the anterior division of the 

 body, and rather densely setous, all the articulations sharply defined. Posterior 

 antennse with the outer ramus more than twice as long as the inner, terminal 

 joint of the latter with only 3 or 4 setse on each of the lobules. Posterior max- 

 illipeds with the 2nd basal joint almost twice as long as the 1st, and considerably 

 dilated in the middle, terminal part scarcely half as long, and more or less incurved, 

 with the 2 outer joints very small, procurved setse of the preceding ones very 



