1914.] NATURAL SCIENCES OF PHILADELPHIA. 53 



The males are only a little smaller — 1.6 mm. being an average length 

 for local specimens. The coloring of C. phaleratus is most brilliant. 

 The ground-color, which in this species is directly in the chitin, is a 

 brick-red. The second thoracic segment, the last abdominal segment, 

 the stylets and the caudal setae and spines, the swimming feet, the 

 mouth parts, second antennae, and the last segment of the first antennae 

 are sky-blue, which varies in intensity. Often these parts appear 

 quite colorless. The egg-sacs are dark blue or lavender in the first 

 stages of development. 



C. phaleratus is a pelagic species. In aquaria it may often be 

 found a little above the water line, where it sometimes crawls even 

 beyond the upper margin of the meniscus line. Its swimming 

 motion is a rapidly darting one. The easiest way of distinguishing 

 it from all other members of the genus is by its superficial resemblance 

 to the genus Canthocamptus. The short, eleven-jointed antennae, 

 and form of the rudimentary fifth feet, are certain microscopic points 

 of identification. 



This species seems to be very widely distributed in America, though 

 nowhere is it particularly abundant. Forbes reports it from several 

 localities in Illinois and Wisconsin and from Portage La Prairie, 

 Manitoba. Marsh has found it in several of the Michigan lakes 

 and Cragin reports it from Cambridge, Mass., as Cyclops per armatus. 

 Miss Byrnes has studied the species on Long Island, where she found 

 it in "shallow, fresh-water ponds." I have noted it rather more 

 abundantly in the spring collections, but never in great numbers from 

 the vicinity of Haverford, Pa., and from a small spring-Avater pond 

 near Gillette, Wyoming, as well as in collections from Lake Winne- 

 pesaukee and the vicinity of Cambridge, Mass. 



Subgenus PARACYCLOPS Claus. 



Cyclops fimbriatus var. poppei Rehberg. PI. IV, figs. 5-11. 



Cyclops poppei Rehberg, '80, p. 550, Taf. VI, figs. 9-11. 



Cyclops fimbriatus Schmeil, '91, pp. 35, 36. 



Cyclops iimbriatus var. poppei Schmeil, '92, pp. 168-170, Taf. VII, figs. 14-16. 



Cyclops' fimbriatus Herrick, '95, pp. 121, 122, pi. XVII, figs. 8, 9; pi. XXI, 



fig. 11; pi. XXV, figs. 9-14. 

 Cyclops fimbriatus var. poppei Forbes, '97, pp. 63 and 65. 

 Cyclops fimbriatus Bj^nes, '09, p. 33, pi. XV. 



Synonymy and Distribution. — In his Beitrdge zur Kenntniss, etc., 

 of '91, Schmeil considered Cijclops poppei Rehberg, synonymous 

 with the typical C. fimbriatus. The following year, however, after 

 a more careful study of the species, though he still claimed the 

 differences to be too few to warrant a new species, he granted that 



