Bull. IT. S. B. F„ 1924. (Doc. 968.) 
Fig. 12. — A monotonous plankton of Calantis finmarchicus, Massachusetts Bay, .Tilly 19, 1916, haul from 
30-0 meters (station 10341). In connection with Figure 13 it illustrates a striking example of vertical 
stratification, with Calanus dominating the shoaler and Sagitta elegans the deeper levels. X 1.75 
Fig. 13. — Plankton dominated by Sagitta elegans, Massachusetts Bay, July 19, 1916, haul from 80 meters (sta- 
tion 10341). In connection with Figure 12 it illustrates local abundance of this chsetognath at the deeper 
levels at a station where the plankton at shoaler levels was almost pure Calanus. X 1.75 
