67 



Distribution. Greenland (Kroyer), Atlantic coast of North America 

 (Yen-ill), Spitsbergen (Nor\v. North All. Kxped.), the Kara Sea (Stuxberg.i, Skage- 

 rak and Kattegat (Meinert). 



Gen. 4. LeptOStyllS, G. 0. Sars, 1869. 



Generic Characters. General form of body that of Diastylis, being some- 

 times very slender, sometimes rather robust, anterior division (at least in female) 

 considerably tumefied and sharply marked off from the tail. Eye wanting. Superior 

 antenna? in female about as in Diastylis, in male conspicuously transformed, the 

 peduncle being greatly dilated, claviform, and clothed at the end with numerous 

 diverging sensory filaments forming a dense brush, which almost conceals the 

 flagella. Inferior antennae in male much more feebly developed than in Din- 

 sti/li*. and scarcely exceeding the anterior division of the body in length. Oral 

 parts and anterior pairs of legs about as in Diastylis. Third and 4th pairs of 

 legs in female with a very small, though distinct biarticulate appendage (rudi- 

 mentary exopodite) outside the basal joint. Pleopoda in male less fully developed 

 than in Diastylis. Uropoda with the rami very slender, the inner one being much 

 the longer, and distinctly 3-articulate. Telson remarkably short, with only a 

 single pair of lateral spinules. 



Remarks. This genus was established in the year 1869 by the present 

 author, to comprise some species formerly referred by him to the genus Diastylis, 

 but. on a closer examination, found to differ in certain characters rather con- 

 spicuously, especially as regards the structure of the antenna? and pleopoda of the 

 male. Another distinguishing character of the female, at first overlooked, is the 

 presence of rudimentary exopodites on the 3rd and 4th pairs of legs, like those 

 found in the genera Lamprops and Hemilnmprops. The generic name Leptostylis 

 is derived from the unusually slender rami of the uropoda ; and the very short 

 telson, with its single pair of lateral spinules, also forms an easily recognizable 

 character of the present genus. We know as yet of 6 species, 4 of which belong 

 to the Norwegian fauna, and will be described below. Moreover, Dr. J. Bonnier 

 has recorded a form from the Gulf of Gascogne as LeptostyUs longicaiulata, which 

 however, in my opinion, cannot properly be referred to the present genus, 

 in spite of its being provided with rudimentary exopodites on the 3rd and 4th 

 pairs of legs. 



