454 Illinois State Lahorato7'y of Natural History. 



relative lengths of the terminal setae of the second feet; 

 also by the difference in the relative lengths of the ter- 

 minal and penultimate segments of the first foot, which 

 in C. sigmoides are as two to three (PI. XLI., Fig. 11), 

 while in the present species they are approximately equal 

 in length. 



Described from a number of specimens collected at the 

 Biological Station of the University of Illinois at Ha- 

 vana, 111., and from specimens collected by myself at 

 Hedges' Pond, near Urbana, 111., April 10, 1896. 



Named for Chas. T. Simpson, of the United States^ 

 National Museum. 



Candona fabseformis S. Fischer. (PI. XLV., Fig. 1-3.) 



1851. Cypris jabceformis, S. Fischer (23, p. 146, PI. III., Fig. 6-16). 



1853. Candona fabceformis, Lilljeborg (39, p. 207). 



1870. Candona diaphana, Brady & Robertson (11, p. 18, PI. Y., 



Fig. 1-3). 

 1889. Candona fabceforniis, Brady & Norman (9, p. 103, PI. IX., 



Fig. 1-4). 

 1891. Candona fabceformis,Y Ayra, (68, p. 45, Fig. 6% 12i-12»). 

 1895. Candona fabfceormis, Turner (35, p. 299, PI. LXXV., Fig. 



10, 11; LXXYI., Fig. 6-8). 



Length 1.00 mm., height .47 mm., width .49 mm. 



Shell yellowish transparent, a few minute papillar ele-' 

 vations on its surface and a few short scattered hairs. 



Seen from the side, it is slightly widest back of the mid- 

 dle, the upper and lower edges nearlj^ parallel, both ends 

 fully rounded, the ventral edge quite deeply sinuate near 

 the middle. 



Seen from above, the shell is long, ovate, the two ends 

 suddenly and equally pointed, the two sides nearly par- 

 allel at the middle. 



Second antennae quite stout; terminal segment slightly 

 longer than wide; terminal claws smooth, slender, and 

 in the female scarcely longer than the last two segments. 



Second foot (Fig. 3) short, slender, the fourth seg- 

 ment divided, making the foot six-segmented. Terminal 

 segment as long as broad, one half as long as the pe- 



