PELAGIC ANIMAL LIFE 



621 



help believing that the profoundest deep is far more poorly 

 supplied than the intermediate layer. 



If we next examine the size-distribution at the different 

 depths, we shall see that it is perfectly clear that the smaller 

 sizes are met with much higher up than the larger ones, 

 which latter are mainly to be found at a depth of 1 500 metres. 

 In the northern section we find that at a depth of 500 metres 

 the greatest number of individuals were 30 mm. in length, 



Fig. 474. 



whereas at 1500 metres the majority attained 60 mm. At a 

 depth of 500 metres we came across only two that were over 

 50 mm. in length. The smaller and younger individuals of 

 a length of 20-30 mm. live, accordingly, to a preponderating 

 extent, 1000 metres higher up in the water-layers than the 

 majority of the largest and oldest individuals. 



Another remarkable fact which strikes us when we study 

 our catches is that the average size of the individuals is much 

 less in the southern than in the northern section at the same 



