44 PROCEEDINGS OF THE ACADEMY OF [Jail., 



Second pair — outer ramus, four spines, five setae; inner ramus, one 



seta, one spine, five setae. 

 Third pair — outer ramus, four spines, five setae; inner ramus, one 



seta, one spine, five setae. 

 Fourth pair — outer ramus, three spines, five setae; inner ramus, one 



seta, two spines, three setae. 



The above armature is quite constant. Herriclc states the fifth 

 foot is two-jointed. Since he has only collected the species in a 

 single instance, this must be considered an error. There is often a 

 very inconspicuous indication of a former large basal segment 

 (PI. Ill, fig. 9), but the movable fifth foot consists of a single cylin- 

 drical joint. At the middle of its distal end there is borne a long, 

 delicatel}^ plumose seta (PL III, fig. 9). 



The shape of the receptaculimi seminis has already been discussed. 

 Fig. 5 of PI. Ill shows what is probably the extreme ''wing-like" 

 formation of the anterior division. The posterior portion is about 

 as long as the anterior and has the form of a short bag. The porus 

 is situated immediately between the two portions on the narrow 

 transverse division that extends entirely across the first abdominal 

 segment. 



The egg-sacs contain from ten to twelve ovae and are carried at a 

 slight angle from the abdomen. 



The following measurements of six females taken at different 

 times give an average length of .867 mm. 



The females average .21 mm. in width. The males are somewhat 

 smaller than the females — .69 mm. being an average length. Schmeil 

 gives .8-.92 mm. for the size of the females and "about" .7 mm. for 

 the males. Sars' figures are somewhat greater — 1 mm. Herrick 

 gives .8 mm. 



The color of C. varicans is ordinarily very pale. A faint shade of 

 yellow is noticeable throughout the body, making the animal un- 

 usually inconspicuous. It may ])e readily distinguished from all 

 other species of the genus by its short, twelve-jointed antennae, the 

 very characteristic receptaculum seminis, and th(^ two-jointed swim- 

 ming feet. 



