301 



natatory legs transformed. Last pair of legs differing somewhat from those in 

 female, distal joint comparatively shorter, and only provided with one apical and 

 one small lateral seta; inner expansion of proximal joint scarcely at all produced, 

 and carrying 2 unequal setse. 



Colour whitish grey. 



Length of adult female 0.64 mm. 



Remarks. This form, in spite of its external resemblance to certain species 

 of the genus Cletodes, ought evidently to be referred to the present genus, agreeing, 

 as it does, in all essential anatomical details with the type of that genus, E. curti- 

 caudatum, from which it chiefly differs in the more slender form of the body and 

 in the shape of the caudal rami and the last pair of legs. 



Occurrence.}, have found this form rather abundantly at Skutesnses, south- 

 west coast of Norway in a few fathoms' depth, muddy bottom. It also occurs 

 occasionally off the south coast, as also in the upper part of the Christiania Fjord. 



Distribution. British Isles (Brady). 



199. Enhydrosoma longifurcatum, G. 0. Sars, n. sp. 



(PI. CCVU). 



Specific Characters. Female. Body somewhat less slender than in E. pro- 

 pinqvum. Cephalic segment rather large, about equalling in length the 3 suc- 

 ceeding segments combined, rostral projection broadly triangular and slightly 

 recurved at the tip. Urosome (including the caudal rami) almost as long as the 

 anterior division, last segment a little larger than the preceding one, and broadly 

 emarginated behind, lateral edges convex and exhibiting at a short distance from 

 the end a knob-like projection tipped with a delicate bristle. Caudal rami remark- 

 ably produced, being about twice as long as the anal segment, very narrow linear 

 in form and somewhat divergent, lateral setse far apart, the one attached to a 

 distinct ledge close to the base, the other nearer the end, dorsal seta issuing in 

 front of the middle, apical seta rather slender, considerably exceeding in length 

 the ramus itself. Anterior antenna? short and stout resembling those in E. pro- 

 pinqvum. Posterior antenna? and oral parts likewise of a very similar structure. 

 Natatory legs comparatively less fully developed, though on the whole exhibiting 

 the structure characteristic of the genus. Last pair of legs with the distal joint 

 comparatively short, conical in form, with the marginal setse less strong than in 

 the 2 preceding species ; inner expansion of proximal joint rather small, but armed 



40 Crustacea. 



