GENERAL BIOLOGY 



667 

 when 



still visible ; and {4) gonads also concealed by pigment 

 viewed from above. 



For each of these varieties Broch has recorded the vertical 

 distribution observed, as represented in the following table, the 

 figures denoting the number of specimens found in each 

 layer : — 



Even if the difference between Nos. 2, 3, and 4 is not strongly 

 marked, the increase in dark pigment following the increase 

 in depth is still very perceptible. 



Another instance of this is afforded by the following table, 

 showing the vertical distribution of eleven species of pelagic 

 decapod Crustacea, according to the results of Sund's examina- 

 tion of the " Michael Sars " decapoda : — 



[Table 



