no. 1051. REPORT ON TEE OSTRACODA—HII YRPE. 409 



Dimensions. — Length, 0.-l~> to 0.48 mm.; breadth, 0.24 to 0.28 nun.; 

 height, 0.3 to 0.34 mm. 



The shell varies in color from a lemon yellow to chestnut red, 

 Vavra, 1891, even reporting them of a whitish color but ordinarily 

 horn-brown. I have seen none of any other color than lemon yellow 

 to chestnut red. 



Seen from the side (Plate LTV, fig. 5), the highest point of the shell 

 is almost exactly in the middle, approximately seven-ninths as high as 

 long. The dorsal margin is rather plainly humped in the middle, 

 posterior margin evenly rounded, ventral margin nearly straight, or 

 weakly convex. 



Seen from above (Plate L, fig. 5), the shell is egg-shaped, pointed 

 anteriorly, the left shell slightly overlapping the right anteriorly; 

 greatest width in the middle, the width being slightly more than 

 one-half or about three-fifths of the length. 



Terminal segment of the second foot (fig. 7) about three times as 

 long as wide. Terminal claw about as long as the width of the ter- 

 minal segment; shorter seta about four times as long as the claw; 

 penultimate segment about five-thirds as long as the terminal one, 

 and armed with two setae on its inner edge, while C. forbesi has but 

 one such seta, the outer margin of the segment having three combs of 

 minute teeth. The terminal claw of one of the specimens examined 

 was weakly S-shaped. Kaufmann " mentions this peculiarity as a 

 common occurrence, and uses it as of specific worth. It would rather 

 seem to be characteristic of the younger stages of growth, however, 

 as it was in no wise a constant character in the American specimens 

 examined. 



Furca (fig. 6) stout, nearly straight, one-sixth as wide as long, 

 measured along the anterior edge; terminal seta varying from one- 

 half to two-thirds length of the terminal claw. Terminal claw stout, 

 slightly curved near tip, toothed near tip, and about one-half length 

 of ramus measured along anterior margin, while in C. globosa this 

 proportion is about as 1 to 3. Subterminal claw also slightly curved 

 near tip, toothed, and but little shorter than terminal claw. Dorsal 

 seta hardly distinguishable, and. indeed, usually entirely lacking. 



This species seems to be a somewhat variable one, which likely in 

 part accounts for the unusually large synonymy as given by some 

 authors. 



Described from several specimens collected rather commonly from 

 ponds and swamps southeast of Chicago, Illinois, and at Clarke Junc- 

 tion. Indiana. They were collected amongst rushes, water Lilies, 

 sphagnum moss, typha, etc.: also found at Kissena Park lake. Long 



"Revue Suisse cle Zool., VIII, 1900, p. 320. 



