1094 Wisconsin Academy of Sciences, Arts, and Letters. 



middle or end of the second cephalothoracic segment. The 

 setae of the antennal appendages are unusually long. 



The spinous armature of the terminal segments of the exo- 

 podites of the swimming feet is 4, 4, 3, 3. This is an un- 

 unusual armature. 



The fifth foot (PI. LX XVIII, fig. 3) is three segmented. 

 The first segment is short and without armature. The second 

 segment is nearly square and bears a seta on its outer distal 

 angle. The third segment is narrower, longer than wide and 

 bears two apical setae. Frequently the outer of these setae is 

 bent over the inner. 



Length of the females 1.2 to 1.25 mm. 



This was first described by Herrick from Alabama, and he 

 afterwards reported finding it in Minnesota. I found it in 

 two localities in Wisconsin and Forbes reports it from Wyom- 

 ing, and states that it is an uncommon species in the north 

 central states. I have received specimens from R. A. Spaeth 

 collected at Haverford, Pennyslvania, and from C. F. Baker 

 collected at Auburn, Alabama. 



CYPLOPS SERRULATUS Fischer. 



Plate LXXVIIL. Fiss. 



Plate LXXIX, Figs. 4 and 8. 



1851. Cyclops serrulatus Fischer, p. 423, pi. X, figs. 22, 23, 26-31. 



1853. " " Lilljeborg, p. 158, pi. XV, fig. 12. 



1857. " " Claus, p. 36, pi. I, figs. 1-3. 



1863. " " "p. 101, pi. I, figs. 1 and 2, pi. IV, fig. 12, 



pi. XI, fig. 3. 



1863. " " Sars, p. 254. 



1863. " " Lubbock, p. 197. 



1870. " " Heller, p. 72. 



1872. " " Fric, p. 222, fig. 18. 



1875. " " Uljanin, p. 34, pi. VIII, figs. 1-8. 



1876a. " " Hoek, p. 22. 



1878. " " Brady, p. 109, pi. XXII, figs. 1-6. 



1878. " " var. montanus Brady, p. 110, pi. XXII, figs. 7-14. 



1880. " agilis Rehberg, p. 545. 



1882. " " Forbes, p. 649. 



1882. " serrulatus Herrick, p. 230, pi. V, figs. 1-5, pi. VII, fig. 10. 



1883. " " G. M. Thompson, p. 96, pi. XI, figs. 19-22. 



1883. " pectinifer Cragin, p. 6, pi. IV, figs. 1-7. 



1884. " serrulatus Herrick, p. 157, pi. 0, figs. 17-19. 

 1884. var. elegaas. Herrick, p. 158. 



