3° 



COLD SPRING HARBOR MONOGRAPHS. 



vn. 



Foot No. 



Ramus, Outer or Inner.. 



Outer Spines 

 Apical Spines 

 Apical Seta . . 

 Inner Setre . . 



II 



11 



1 



1 



III 



IV 



11 

 1 

 1 

 4 



11 

 22 

 

 3 



•l-seta. ^unequal. 



Herrick does not give the armature of the first, second, and third 

 feet of the inner ramus, and on the outer margin of the inner ramus 

 of the fourth foot, he records a spine. The fifth foot bears one 

 long hair without barbs or serrations on its apex. It consists of a 

 single cylindrical segment, of which the length is approximately four 

 times the width. The abdomen is rather slender and bears the 

 usual caudal stylets, armed with two long terminal setse. The 

 median seta is longer than the outer one. At the base of the setae 

 are three short stout hairs without barbs or serrations ; a delicate one 

 on the median side of the long setse, and a stouter one on the outer 

 angle of the stylet. The third hair is posterior and small. From 

 the side of the stylet, near its middle region, projects a stout hair, 

 almost at right angles. 



The particular Cyclops studied was a female without ova and 

 containing numerous orange colored spheres, characteristic of young 

 individuals; but that the form was sexually mature is shown by 

 the enlargement of the first abdominal segment as well as by the 

 enlarged receptaculum seminis. 



Its antennre were twelve- jointed ; rami of the swimming feet, two- 

 jointed; fifth foot, one-jointed. 



The species C. bicolor is usually placed (e. g., by Marsh) among 

 Cyclops having ten or eleven segments. The occurrence, there- 

 fore, of a twelve-jointed antenna shows that considerable varia- 

 tion may occur in this organ. Except in this respect the form from 

 Cold Spring Harbor agrees with Professor Marsh's description. 



Herrick* (1895, p. 119) finds the fifth foot consisting of "a 

 fleshy basal segment more or less coalesced with the last thoracic 



* "Copepoda, Cladoccra and Ostracoda of Minnesota." Geological and 

 Natural History Survey of Minnesota. 1895. 



