430 Wisconsin Academy ff Sciences, Arts, and Letters. 



segment. The third segment is represented by two spines, of 

 which tlie outer is the longer. The endopodite is slender, ter- 

 minating in a blunt point. It is a little longer than the first 

 segment of the exopodite. It is setose at tip, and has two rather 

 long terminal spines. 



The spines of the first basal segments of the male fifth feet 

 are small and acute. The second basal segment of the right 

 foot is twice as long as broad. The lateral hair is situated at 

 the beginning of the distal third. The first segment of the ex- 

 opodite is broader than long, the proximal end being much 

 narrower than the distal. The inner distal angle bears a small 

 hyaline appendage. The second segment equals in length the 

 combined length of the second basal segment and the first seg- 

 ment of the exopodite. The segment is widest at the end of the 

 proximal third, and from this point springs the lateral spine; 

 this is rather long, acute, with a rather abrupt curvature just 

 above the base. The terminal hook is slender, falciform with 

 a symmetrical curvature, and considerably exceeds in length 

 the rest of the exopodite. It is minutely denticulate on the 

 inner margin. The endopodite is slender, equaling or exceed- 

 ing in length the first segment of the exopodite. The left fifth 

 foot extends to about the end of the first segiuent of the exopo- 

 dite. The second basal segment is about half the length of the 

 corresponding segment of the right foot. The lateral hair is 

 long and slender, and situated at the beginning of the distal 

 third. The first segment of the exopodite equals the second 

 basal segment in length; its length exceeds its width by about 

 one-half. The second segment equals in length the first, but 

 is much narrower; it is terminated by two small finger-like 

 processes. Both segments of the exopodite are setose on the 

 inner margin. The endopodite is long, slender, curved, and 

 reaches to about the middle of the second segment of the exopo- 

 dite. 



Length of female, 0.97 mm. Length of male, 0.89 mm. 



The original description was from material collected by Pro- 

 fessor Birge at Ashland, on Lake Superior. It occurs in all 

 the Great J^akes, and I have found it in Michigan in Pine lake 



