UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 16, No. 14, pp. 171-184, 2 figures in text March 17, 1916 



THE FEEDING HABITS AND FOOD OF PELAGIC 

 OOPEPODS AND THE QUESTION OF 

 NUTRITION BY ORGANIC SUB- 

 STANCES IN SOLUTION 

 IN THE WATER 



BY 



CALVIN O. ESTERLY 



It is well known how some of the animals that feed on the minute 

 organisms of the plankton obtain their food. For example, the par- 

 ticles ingested by the appendieularians are gathered by means of a 

 screen-like arrangement that separates them from a current of water. 

 Or, as in the ease of the Salps, the food material is entangled in mucus 

 and then carried to the opening of the esophagus. 



The matter is different, however, when such forms as the Copepoda 

 are considered. These animals are provided with well-developed ap- 

 pendages which have a varied equipment of bristles. The copepods 

 feed upon the minute animals and plants of the plankton (Peck, 1896; 

 Dakin, 1908), and it is a rather interesting question how the complex 

 appendages are used in getting food. Such organisms as diatoms are 

 too small to be grasped or manipulated by the bristles of the mouth 

 parts, yet the copepods ingest diatoms in large numbers. 



.The literature, so far as I have been able to discover, contains no 

 accurate information as to the method by which the pelagic copepods 

 get their food. Dakin (1908, p. 776) speaks of "the food-matter 

 caught by the mouth appendages and introduced into the mouth by 

 the mandibles," but he does not say much more about the process. 

 Lohmann (1911, p. 11) states casually that a large part of the cope- 

 pods make the same filtration experiment as the appendieularians. 



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