180 American Fisheries Society 



Peck, in his splendid paper on The Sources of Marine 

 Food, gives us an excellent example of the food relations 

 described by Leeuwenhoek. Reporting on the stomach 

 contents of the squeteague he says, "On the morning of 

 July 23 there was taken a large specimen whose stomach 

 contained an adult herring. In the stomach of the 

 herring were found two young scup (besides many small 

 Crustacea), and in the stomach of one of these scup 

 were found copepods, while in the alimentary tract of 

 these last one could identify one or two of the diatoms 

 and an infusorian test among the mass of triturated 

 material which formed its food. This is an instance of 

 the universal rule of this kind of food : The squeteague 

 captures the butterfish or squid, which in turn have fed 

 on young fish, which in their turn have fed upon the 

 more minute Crustacea, which finally utilize a micro- 

 scopic food supply." These microscopic organisms con- 

 stitute an unfailing, ultimate food supply and without 

 it the larger animals of the ocean whose chief business 

 is to devour each other, would soon exterminate them- 

 selves. It consists of single-celled plants and animals, 

 chief among which are the diatoms and radiolarians. 

 According to Peck these two groups alone may be re- 

 garded as the great primary food supply for the larger 

 marine animals. The diatoms in particular may be said 

 to constitute the pastures of the sea. 



How these minute creatures can support such a large 

 and extensive fauna may be readily understood when 

 their habits are known. They grow under far more 

 advantageous conditions than our land plants and con- 

 sequently grow faster, almost infinitely faster. Land 

 plants have a portion only of their bodies in the ground 

 and can absorb the mineral elements necessary for their 

 growth only as the rains dissolve them. Being crowded 

 into limited space and subject to seasons of drought and 

 cold their growth is constantly arrested. 



On the other hand the microscopic marine plants are 

 bathed in a uniform solution of mineral food, they have 

 the full benefit of the sunlight and the temperature of 



