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



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

 geuus, constituting powerful natatory organs, with very elongate and multiarticulate 

 branches. In tlie 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. G) is a trifle longer than the last segment and somewhat slender, as 

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

 fringed with small, slightly unequal, denticles. The apical incision does not full}- occupy 

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

 fi'inged 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 appearance as in the two Norwegian species 

 Boreomysis arctica and Boreomysis tricornis, 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. (ofi" coast of Japan); 

 depth, 345 fathoms; green mud; bottom temperature, 41°"1. 



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). 



Boreomysis microps, G. O. Sars, Preliminary Notices on the Challenger Schizopoda, No. 43. 



Specific Chai'acters. — Female : — Form of body somewhat more slender than in the 

 preceding 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 the 

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

 Antennal scale surpassing 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 ; apical 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 fntm the other species of 

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

 denomination was taken. Moreover, the slender form of the telson would seem to afford 

 a good specific mark. 



