25 



of the distal joint; marginal setae shorter than in the preceding species and 

 rather unequal. 



Male much smaller than female, but exhibiting a very similar form of 

 the body. Anterior antennas transformed in the usual manner, but highly 

 distinguished by the presence of a largely developed aesthetask attached by a 

 short chitinous stalk to the upper face of the greatly tumefied median joint, 

 and extending backwards along the side of the cephalic segment until its very 

 end. Last pair of legs, as usual, much reduced in size. 



Colour light yellowish. 



Length of adult female 0.88 mm.; that of male 0.72 mm. 



Remarks. This form is nearest allied to E. propinqvum Scott, but is 

 of more slender form of body, and moreover at once distinguished by the very 

 different shape of the rostral plate, which is far less prominent and not, as in 

 that species, spoon-shaped, but distinctly angular in front. 



Occurrence. I have only met with this form in a single locality on 

 the Norwegian coast, viz., at Riser, where several specimens, both males and 

 females, were found in depths ranging from 30 to 60 fathoms, muddy sand. 



16. Ectinosoma tenerum, G. O. Sars, n. sp. 

 (PI. XVI, fig. 1). 



Specific Characters. Female. Body exceedingly slender and narrow, 

 seen dorsally, almost linear in form. All the integuments very thin and pellucid. 

 Rostral plate somewhat prominent and, seen dorsally, narrowly truncated in 

 front, the tip being abruptly recurved. Urosome scarcely exceeding in length 

 the exposed part of the trunk, and very slightly tapered behind; genital segment 

 about the length of the 2 succeeding segments combined; anal segment, as 

 usual, the smallest. Caudal rami very short, being scarcely as long as they 

 are broad; apical setae of moderate length. Anterior antennae more slender 

 than in the 2 preceding species and rapidly tapering distally, being composed 

 of 6 well-defined joints, the 2nd of which is somewhat dilated in front. Anterior 

 lip, as in most other species of the present genus, projecting below in an 

 acute recurved process. Anterior maxillipeds unusally powerfully developed, 

 with the 2nd basal joint very large and muscular; apical claws much elongated 

 .and abruptly curved in their outer part, which is moreover finely denticulate 

 inside. Posterior maxillipeds very slender and narrow. Natatory legs of the 

 usual appearance. Last pair of legs resembling somewhat in shape those in 

 E. angulifrons ; outermost lobe of the distal joint, however, far remote from 



4. Crustacea. 



