24 



synonymy, see Kurz (I. a. p. 77). The mandibles are articulated, 

 not where the fornix joins the valve, but behind this point. This 

 fact is noted by Kurz in C. ovalis, and his figures show that the 

 same is true of C. globosus ; although his description of C. glo- 

 bosus would imply otherwise. A chitinous ridge runs from the 

 the point of articulation of the mandible, above the junction of 

 the fornix and the valve, along the under side of the fornix to the 

 rostrum. It does not stop at the junction of fornix and valve, as 

 figured by Kurz in C. ovalis. 



This species is common wherever I have collected, and is pres- 

 ent in dense swarms near the surface of the water on bright, 

 warm, calm days. It is one of the earliest of the Lynceinoe to ap- 

 pear in the spring. 



SPECIES 2. 

 Chydorus G-lobosus. Baird. 



For synonymy, see Kurz (1. c, p. 18). 



One specimen from Lake Wingra, Madison, Wis., Sept., 1877. 



GENUS 3. 



Cjeiepidocercus. gen. nov.* 



The head is immovable. The rostrum is sharp, but does not 

 extend downward for more than half the distance between the ar- 

 ticulation of the mandible and the ventral edge. The dorsal 

 margin is much arched, and rounds evenly over, terminating be- 

 hind iu a somewhat sharp angle. The posterior margin is sinu- 

 ate, concave above, then convex. Just in front of the junction of 

 the posterior and ventral margins is a single strong, recurved 

 tooth. The ventral margin is slightly concave and the anterior 

 margin strongly convex. The valves are marked by the " stiitz- 

 balken," as in all Cladocera, and by an obscure reticulation of ir-, 

 regular hexagonal meshes, most clearly marked in the hinder 

 portion of the valves, where the longer axis of the meshes runs 

 obliquely downward and backward. 



* From xpynk, shoe, and xepxoz, tail. 



