Material studied (coordinates, depth and bottom see Appendix). 13 th Soviet (Russian) Antarctic Expedition station 3, samples 2 and 3: 2 juveniles.
Station 30, sample 68: juvenile.
16 th Soviet (Russian) Antarctic Expedition Davis Sea, Haswell Island: juvenile.
52 th Russian Antarctic Expedition, Prydz Bay, station 12, sample 64: juvenile.
Bathymetrical distribution. The Antarctic shelf is inhabited by 9 philomedid species: P. c h a rc o t i, P. orbicularis, P. assimilis, S. gallardoi (all from 10–15 m and deeper), P. rotunda, A. dithrix, S. appelloefi (all from 60–70 m), S. tuberculata sp. nov. and P. heptathrix (both from 200–250 m) (Fig. 41). The lower depth limit for P. charcoti and A. dithrix is 100–150 m and 200–250 m for P. rotunda and S. appelloefi. The lower part of the shelf is inhabited by P. orbicularis, P. assimilis, P. heptathrix, S. gallerdoi and S. tuberculata. In the bathyal zone are found P. assimilis, P. tetrathrix, S. gallardoi and S. tuberculata, while the only philomedid species currently known from the abyssal zone are P. tetrathrix and I. walleni.