long sensory filaments. Mandibles of a similar structure to that in Calathitra, 

 but having the palp smaller, with the terminal joint rudimentary. Maxillipeds 

 narrow, with the basal part imperfectly donned from the palp, which is only 

 composed of 2 joints, the distal one very small and narrow, masticatory lobes 

 obsolete. 1st pair of legs very strong, proj)odos produced at the end of the palm 

 to a very conspicuous, thumb-like process, giving these legs an almost chelate 

 character; the 2 succeeding pairs with the propodos of different shape in the two 

 sexes. 1st pair of pleopoda less fully developed than in Calathitra, so as not to 

 obtect the others below. Uropoda with the inner ramus rather slender, outer one 

 very broad and but sparingly setous. Telson lanceolate, terminating in an 

 acute point. 



Remarks. — The present new genus is founded upon the form at first recorded 

 by the present author as Paranthura tenuis, and subsequently referred by him to . 

 the genus Ptilanthura of Harger. On a closer examination, I have, however, 

 found it necessary to separate this form also from the above-named genus, on 

 account of some apparently very essential differences. Messrs. Norman & ' tebbing 

 retain it in the genus Paranthura; but this seems to me inadmissible, as it ex- 

 hibits several very marked differences from that genus, both in the structure of 

 the oral parts and in that of the other appendages. The structure of the 1st 

 pair of legs in this genus is rather remarkable from the circumstance that it ex- 

 hibits a very pronounced approach to a chelate character, like that found in 

 the Tanaidse. 



Leptanthura tenuis, G. 0. Sars. 



(PI. XX.) 



Paranthura tenuis, 1 ) G. 0. Sars, Bidrag til Kundskaben om Dyrelivet paa vove Havbanker. 

 Chr. Via. Selsk. Porh. 1872, p. 89. 



Specific Characters. — Body, especially in male, exceedingly slender, almost 

 filiform, with all the segments very sharply defined. Cephalon about half the size 

 of the 1st segment of mesosome and scarcely narrower, almost quadrate in out- 

 line, frontal margin slightly bi-sinuate. The first 2 segments of mesosome and 

 the last of about equal size, the 4 others somewhat longer, being more than 

 twice as long as they are broad; dorsal face of all segments perfectly smooth. 

 Metasome, including the telson, in female about the length of the last 2 segments 

 of mesosome combined, in male considerably longer, somewhat fusiform in shape, 



') P. tenuis of Harger, established some years afterwards, is a very different species, not 

 even belonging to the same genus. 



