SECT. 4] 



BIOLOGICAL SPECIES, WATER-MASSES AND CURRENTS 



395 



Nematoscelis gracilis 



Fig. 6. Geographical distribution of equatorial euphausiid species, Nematoscelis gracilis (a) 

 and Euphausia distinguenda (b). The only other localities for these two species are 

 in the equatorial water-mass of the Indian Ocean. Crosses in (a) indicate non- 

 quantitative records for N. gracilis, and in (b) all known localities for E. sibogae, a 

 species related to E. distinguenda. 



