An account is given of the feeding mechanism of some freshwater cyclopoid copepods.
Chance encounter appears to play an important part in the finding of food in both carnivorous and herbivorous species, but the chemoreceptor organs apparently utilized by the herbivores to discriminate between edible and inedible particles may help to some extent in food seeking.
The structure, arrangement, and method of operation of the various mouthparts are described, and the raptatory method of feeding of the cyclopoids is demonstrated.
The route taken by the cyclopoids towards a parasitic mode of life is considered from a functional standpoint.
The phylogeny of the Cyclopoida and Calanoida is discussed. A carnivorous diet is considered to be the primitive diet of the Cyclopoida. A change from a carnivorous to an algal diet may have been of considerable importance in the adaptive radiation of the group.