216 Marsh — Cyclopidm and Galanidm of Wisconsin. 



three-fourths as long as the furca, projecting laterally from the 

 body. At the other extreme is the pelagic form, C. elegans Her- 

 rick. It averages 1.25 mm in length. The furca is once and a 

 third as long as the last two abdominal segments, and the ex- 

 ternal terminal seta is short and weak. 



Sometimes the two forms occur together in pelagic collec- 

 tions, but only once have I found the elegans form as a littoral 

 species. The European form is, in its characteristics, interme- 

 diate between these extreme forms. 



Although the extreme varieties sometimes occur together, 

 they are almost always entirely distinct. In only two localities 

 have I found connecting forms. In Heart Lake I found an in- 

 termediate form associated with the smaller variety, and in 

 Lake Puckaway I found the typical form in connection with 

 both extremes. 



Cyclops phaleratus Koch. 



Plate VI, figs. 6 and 7. 



1841. O. phaleratus Koch (3), H 21, pi. IX. 



1851. " canthocarpoides Fischer (5), p. 216, pi. X, figs. 24, 



32-38. 



1853. " " Lilljeborg (6), p. 208. 



1857. " " Claus (7), p. 37, pi, I, figs. 6-10. 



1863. " " " (9), p. 102, pi. IV, figs. 1-4. 



1863. " " Lubbock (10), p. 202. 



1863. " phaleratus Sars (11), p. 46. 



1872. " canthocarpoides Fric (13), p. 223, fig. 19. 



1874. " lascivus Poggenpol (14), p. 72, pi. XV, figs. 22-24; 



pi. XVI, figs. 7 and 8. 



1875. " phaleratus Uljanin (15), p. 38, pi. IX, figs. 1-5. 

 1878. " " Brady (18), p. 116, pi. XXIII, figs. 7-13. 



1882. " adolescens Herrick (23), p. 231, pi. VI, figs. 16-20. 



1883. " perarmatus Cragin (24), p. 7, pi. I, figs. 9-18. 



1884. " phaleratus Herrick (26), p. 161, pi. R, figs. 6-10. 



1885. " " Daday (27), p. 252. 



1887. " " Herrick (30), p. 14, pi. VII, fig. 2, a-d. 



1891. " " Schmeil (37), p. 36. 



