40 PROCEEDINGS OF THE ACADEMY OF [Jan., 



point. The lamella of the second pair is similar to that of the third, 

 while in the first pair the chitin points have become quite rounded 

 and smooth. 



The fifth foot (PL II, fig. 9) is generally considered as having three 

 joints. Forbes states that it "has three freely movable segments, 

 though the basal one is small." Miss Byrnes simply states that 

 "the fifth foot is very distinctly three-jointed, and not 'obscurely' as 

 Herrick observed." The basal segment is certainly very short, 

 though its presence is no longer a matter of conjecture. Whether 

 it is "freely movable" I am unable to say. The second segment 

 is almost square and bears a short seta on its outer side. They are 

 both plumose and the larger is borne at the end of a slight projection 

 of the segment. The shorter of these set® is usually folded under the 

 longer, as shown in the figure. The rudimentary feet in this species 

 are unusually large. 



The receptaculum seminis is very much like that of C. bicuspidatus 

 Claus. The anterior division is very low, extending but a little 

 beyond the porus. The posterior, bag-shaped portion reaches half- 

 way to the posterior margin of the abdominal segment. 



The egg-sacs are narrow and extend a little beyond the ends of 

 the stylets. They usually contain from 10-12 dark ovae. 



Forbes gives 1.2 mm. for the length of C. modestus. 1 find it 

 slightly larger, 1.3 mm. being an average length for females. 



The color of this species is most beautiful, violet and lavender 

 shades predominating. It is evenly distributed in the chitin and 

 persists in preserved material. There are usually a number of 

 large, orange-colored globules below the chitin. These are specially 

 numerous in the cephalothorax and the swimming feet. 



C. modestus can be readily distinguished from all other species by 

 the sixteen- jointed first antennae, the three-jointed fifth foot, the 

 very characteristic stylets, and the receptaculum seminis. 



While nowhere an abundant species, C. modestus appears to be 

 very generally distribute^d over the United States. Forbes reports 

 it from several localities hi Illinois and from Grebe Lake in the 

 Yellowstone Park. Marsh found it in Rush Lake, Wisconsin, and 

 Herrick in Cullman County, Alabama. Miss Byrnes has recently 

 studied the species from the Long Island waters. I have found it, 

 always in small numbers, one of the rarer species of the genus from 

 this locality. 



In a collection from "Fresh Pond," Cambridge, Mass., made in 

 the fall of 1909, this form outnum])ered all other species. It occurs 



