Plate XVII. 



{Top) The copepod Calamis finmarchicus and the cladoccran Evadite iiorthiuiiini. 



{Bottom left) The cladoccran Podoii intermcdiits. 



{Bottom rii^lit) The rock pool copepod Tiqriopus fiili'us, a mature male is seen mating with a 



stage V female. 

 Photographs {top and bottom left) from the living plankton 

 by D. P. Wilson; {bottom right) by James Fraser 



