184 THE VOYAGE OF H.M.S. CHALLENGER. 



The caudal limbs are developed precisely as in the males of the other species of the 

 gemis, constituting powerful natatory org-ans, with very elongate and multiarticulate 

 branches. In the first pair, however, the inner branch is, as usual, non-articulate, 

 forming an oblong membranous plate, with a short lateral expansion at the base. 



The telson (fig. 6) is a trifle longer than the last segment and somewhat slendei-, as 

 compared with that of the preceding species, with the outer part narrowed and densely 

 fringed with small, slightly unequal, denticles. The apical incision does not fully occupy 

 one-fifth of the length of the telson, and is narrowly rounded at the bottom, as also 

 fringed with numerous short spinules. The terminal lobes are somewhat narrow and 

 obtusely rounded at the tip, and their apical denticles would not seem to exceed in 

 length the lateral. 



The uropoda exhibit much the same a^jpearauce as in the two Norwegian species 

 Boreomysis arctica and Bofeomysis tyicornis, having both plates somewhat more slender 

 than in Boreomysis scyphops. 



Habitat. — The two specimens contained in the collection were both taken in the 

 North Pacific in the following localities : — 



Station 232, May 12, 1875 ; lat. 35° 11' N., long. 139° 28' E. (off coast of Japan); 

 depth, 345 fathoms; green mud; bottom temperature, 41°'l. 



Station 252, June 12, 1875 ; lat. 37° 52' N, long. 160° 17' W.; depth, 2740 fathoms ; 

 red clay ; bottom temperature, 35°'3. 



45. Boreomysis microps, G. 0. Sars (PI. XXXIII. figs. 7-10). 



Bvreomyds luicrops, G. 0. Sars, Preliminary Notices on the Challenger Schizopoda, No. 43. 



Specijic Characters. — Female : — Form of body somewhat more slender than in the 

 j>receding species. Frontal margin of carapace arched, with a small pointed projection 

 in the middle. Last caudal segment elongate, tapering. Eyes unusually narrow, almost 

 fusiform, with cornea not in the least expanded, and occupying but a small part of tlie 

 eye. Antennular peduncle relatively more slender than in Boreomysis ohtusata. 

 Antennal scale surj)assing antennular peduncle by only one-fourth of its length, oblong- 

 linear, apex obtusely truncate, with denticle of outer corner very small. Telson exceed- 

 ingly slender and greatly narrowed in outer part ; lateral edges armed with strong 

 denticles along with numerous much smaller ones ; aj)ical incision occupying only from 

 one-seventh to one-eighth of the length of telson, very narrow at bottom ; terminal lobes 

 rounded at tip. Length, 24 mm. 



Remarks. — The present form may be at once distinguished from the other species of 

 the genus by its unusually small and narrow eyes, a character from which the specific 

 dentimination was taken. Moreover, the slender form of the telson would seem to afibrd 

 a good specific mark. 



