67_ 



legs exceedingly slender, with the terminal joint of outer ramus narrower than in 

 the preceding species and almost as long at the other 2 combined. Last pair of 

 legs with the distal joint narrow oblong in form and slightly tapered towards the 

 end, 2 of the outer-edge setae attached near the base of the joint at some distance 

 from the 3 other setae; inner expansion of proximal joint short and broad, 

 transversely truncated at the end, and scarcely extending beyond the middle 

 of the distal joint; marginal setae rather slender, the outermost one the longest. 



Colour not yet ascertained. 



Length of adult female 0.41 mm. 



Remarks. This form is still more closely allied to the type species, and 

 may on the first sight easily be confounded with it. It is however of smaller 

 size and, on a closer examination, exhibits also some well-marked differences 

 in the structural details, as indicated in the above diagnosis. 



Occurrence. Some few female specimens of this dwarfed species were 

 picked up from samples taken at Riser in depths ranging from 30 to 50 fathoms. 



55. Cletomesochra rostrata, G. O. Sars, n. sp. 



(PI. XLIV). 



Specific Characters. Female. Body moderately slender, with the an- 

 terior division conspicuously broader than the posterior. Cephalic segment 

 comparatively large, occupying more than half the length of the anterior 

 division; rostral plate greatly prominent and acutely produced at the end. 

 Urosome somewhat shorter than the anterior division, with the segments rather 

 sharply marked off from each other and distinctly spinulose at the hind edge; 

 last segment of about same size as the preceding one and somewhat widening 

 distally; anal opercle finely denticulate at the edge. Caudal rami oblong 

 quadrangular in form, being somewhat longer than they are broad; apical 

 setae rather slender. Anterior antennae of somewhat larger size than in the 

 other species, though not nearly as long as the cephalic segment, 3rd joint 

 remarkably produced at the end anteriorly. Posterior antennae with the outer 

 ramus of moderate size and carrying 4 setae, 2 apical and 2 lateral. Mandi- 

 bular palp with the basal part somewhat dilated and carrying outside a distinctly 

 developed outer ramus. 1st pair of legs with the inner ramus slightly longer 

 than the outer; terminal joint of the latter with 3 outer-edge spines. The 3 

 succeeding pairs of legs exceedingly slender, with the terminal joint of both 

 rami narrow linear in form. Last pair of legs rather unlike those in the other 

 species, distal joint narrow linear in form, with the 2 outermost setae much 



