North American Fresh-water Cyclopid(2. 61 



alone are well developed. The inner one of this pair is from 

 two to three times as long as the outer. Except for the outer 

 side of the outer one of the pair, the anterior third of each is 

 naked. The remainder is usually sparsely plumose. 



The antennae of the female may be either ten- or eleven- 

 segmented and reach only a little beyond the middle of the 

 first cephalothoracic segment. In the ten-segmented antenna 

 the seventh segment bears a delicate sensory hair at its 

 distal end. This hair is borne on the eighth segment of the 

 eleven-segmented antenna. 



The second antennae are short and proportionately broad. 

 On the outer side of the second segment is a double row of 

 spinules. On the upper border of this segment is a spine 

 and a fringe of spinules. This spine and the shortest one at 

 the end of the third segment are very peculiar. Both are 

 strongly curved near the tip, and the inner side of this curve 

 is fringed by a comb-like row of teeth. 



The three-segmented swimming-feet are strongly armed 

 and their outer borders bear rows of long spinules. The 

 armature of the distal segments is as follows : — First pair : 

 outer ramus, three spines, five setae ; inner ramus, one spine, 

 four setae. Second pair : outer ramus, four spines, four setae ; 

 inner ramus, one spine, four setae. Third pair : outer ramus, 

 four spines, five setae; inner ramus, one spine, four setae. 

 Fourth pair: outer ramus, three spines, five setae; inner 

 ramus, one seta, two spines, two setae. 



The rudimentary feet are lateral rather than ventral and 

 consist of mere flange-like processes. They are connected 

 by a row of strong serrations extending across the ventral 

 side of the segment. Each foot is armed by three subequal 

 spines, one naked and the other two plumose. 



The receptaculum son in is consists of two sections, which 

 extend as two narrow bands across the segment. The porus 

 is situated on the median line where the two divisions unite. 



The egg-sacs contain many eggs and are closely appressed 

 to the abdomen. Schmeil calls attention to the fact that the 

 oviducts, which in all other species are contained wholly 

 within the cephalothorax, in ('. phaleratas extend as blind 



