North American FrcsJi-ivatcr Cyclopidce. 63 



nihitiis. This lake is in the Cascade Mountains and is the 

 highest hike of its size in the world. 



As very few ohservations have been made on the Cyclopidie 

 of rivers, I examined a continuous series of collections made 

 in the Illinois Eiver at the Illinois Biological Station, ex- 

 tending from May to September, 1896. In the first of these 

 collections hicii>^])i(J(ttiis was the predominating form, but it 

 soon disappeared entirely, its place being taken by viridls 

 var. iiiserfu.s. From this time throughout the summer /'».s-c('f».s 

 was by far the most abundant form. E<hi,v, riridis var. 

 hreris2)'niosus, IcKckdiil, prdsliius, Hcrrithitic^, and r((r/(7n/-s' were 

 common in the collections, \\\\\\^ jiiiihvi<ifn>i xar. popper, riridis, 

 modestKs, hlcolor, (ilhidK.s, and pludwdtna were of rare occur- 

 rence. 



LIST OF NORTH AMERICAN SPECIES. 



Below is a list of the fresh-water Cyclopida3 reported from 

 America. I have myself seen all of the species of this list 

 except those herein credited to Herrick. 



Genus CYCLOPS. 



I. Subgenus Ciiclops s. str. Claus. 



1. Cyclops h'liekdrfi Claus. 



This is a rare species throughout the north central States. 



2. Cjiclop>i 'nisifpiis Claus, ^/tV/c Herrick. 



Herrick has found at Long Island a form which he identi- 

 ties as this species. 



3. Ci/clojis cfhtx Forbes. 



This is a very common species in the Great Lakes and in 

 the waters of the north central States, Florida, and Wyoming. 

 It occurs in Argentina, South America. 



4. Ciirlops oltJioiioidc.s Sars, //r/c Herrick. 



I regard the occurrence of this species in America as very 

 doubtful. 



5. Ctjrlops diil)oirshil Lande. 



A rare species found only in the small mountain lakes of 

 Wyoming and in a temporary pond at Urbana, Illinois. 



