206 



POPULATIONS OF THE SEA 



Calanus finmarchicus 



CGntropages hamatus 



Fig. 1. The average distribution and abundance of four species taken in the 

 Continuous Plankton Recorder Survey. The contours are based on the average 

 number per sample during the nine years, 1948-1956; they are drawn at abundance 

 intervals of X3. Small dots indicate the centers of sampled squares in which the 

 organism was absent; larger dots show that the species was recorded in small 

 numbers (Colebrook et al., 1961). 



