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ticulations, the outer 2 being confluent, 2nd joint somewhat shorter than 3rd, 

 with a small nodiform projection in the middle behind. Posterior antennae with 

 the outer ramus comparatively short, but of usual structure. 1st pair of legs 

 much stronger than in L. longicaudata, with the inner ramus rather elongated, 

 outer ramus about half the length of the 1st joint of the inner, and only composed 

 of 2 joints, the distal one very slender, linear in form. Natatory legs well devel- 

 oped and of normal structure, proximal joint of inner ramus in all of them with- 

 out any seta inside. Last pair of legs of moderate si/e, distal joint oblong oval 

 in form and densely ciliated on both edges, marginal setse 5 in number, the apical 

 one very slender, hair-like; inner expansion of proximal joint linguiform, extending 

 somewhat beyond the middle of the distal joint, marginal setse 4 in number, the 

 outermost but one much the longest. Ovisac rounded oval in form. 



Male with the inner ramus of 3rd pair of legs transformed in the usual 

 manner. Last pair of legs very small, with the distal joint quite short and only 

 provided with 4 setse, the innermost rather strong, spiniform; inner expansion of 

 proximal joint almost obsolete, though carrying a single well-developed seta. 



Colour dark yellowish. 



Length of adult female 0.90 mm. 



Remarks. This form was first described by Glaus under the name of 

 data similis, and was subsequently also recorded by Prof. Brady. Boeck, how- 

 ever, did not recognise the species, but described it under another name, viz., 

 L. setosa. The form subsequently named by the same author L. affinis is scarcely 

 different from that species. On the other hand, is the form described by Canu 

 as L. similis evidently not that species, as clearly shown by the very different 

 structure of the anterior antennas and the last pair of legs. The present form is 

 one of the larger species of the genus, and may be easily recognised by its slender 

 and graceful body and the very long caudal sette. 



Occurrence. I have met with this form not unfrequently in the upper 

 part of the Christiania Fjord, as also occasionally off the south and west coasts 

 of Norway in moderate depths among algse. 



Distribution. Mediterranean at Nizza (Glaus), British Isles (Brady), ? Franz 

 Josef Land (Scott). 



