Isorth American Fresh-water O&tracoda. 419 



In the second table, the same data are grouped with 

 regard to the time of year, the figures having the same 

 meaning as in the preceding table. The rise in abund- 

 ance in spring is quite evident, and probably would be 

 more so if the earlier months were better represented. 

 The first three genera (Limnicy there, Cyprinotus, and 

 Candona) are absent during the summer months, reap- 

 pearing in fall in lesser numbers. The remaining species 

 (Cypria and Cypridopsis) are more uniformh^ distributed 

 through the year. As they seem more at home in 

 larger bodies of water, while those of the preceding group 

 are accustomed to live iu small ponds and streams which 

 often dry up in midsummer, this difference would natur- 

 ally be expected. 



A full list of the species treated in the following pages^ 

 accompanied by biological data, is next given for com- 

 parison. Unless otherwise specified, the data given are 

 from the records and collections of the State Laboratory. 

 The relative abundance is indicated by a figure, as in the 

 preceding tables. 



The entire absence of species of Cypris from the Biolog- 

 ical Station list is doubtless due to their occurrence in 

 small ponds in preference to larger bodies of water, such 

 as the lakes and streams of the Havana region. 



Family CytheridcE. 

 Lvmnicythere reticulata n. sp. Pond, Urbana, April, (2). 

 illinoisensis n. sp. Lake shore, Havana, I\Iay, (1). 

 These species are evidently crawlers or burrowers 

 rather than swimmers, 



Fannily Cyprididce. 

 Cyclocypris forhesi n. sp. Pond, Bloomington, April. 

 Cyprinotus 2>Gllucida n. sp. In water from creek, Urbana, 

 April; roadsidepool, Havana, Sept., (4) ; creek near 

 Quincy. 

 hurlingtonensis Turner. Jan. and March (Turner); Nor- 

 mal, Ma3^ 

 incongruens Ramd. Abundant in pools in spnng 

 (Vavrn); Pt. Pinellas, Fla., May. 



