6 Trans. Acad. Sci. of St. Louis 



on the antenna is smooth, in others finely serrated. Found in both fetid 

 water and in water havingr no perceptible odor. April, May and July. 

 9. CYCLOPS ALBIDUS Jurine 1820, var. CORONATUS. 



Cyclopa aignatut, var. coronatua, Herriclc & Turner, '95. p. IOC. pi. 

 15, fisr. 1-4. 

 Found only once in this district, amonsr cattails in a shallow pond, the 

 temperature of which was 21 "C. 



10. CYCLOPS BICUSPIDATUS Claus 1867. 



Cyclopa forbeai, Herrick & Turner, '95. p. 104. 

 Cyclopa bicuapidatua, E. B. Forbes, '97. pp. 44-47. pi. 12, fl^. 1-4. 

 Found in this district in four different no-outlet ponds free from vege- 

 tation, but once only in each place. In one pond the temperature was 

 17 "C; in another 19"; temperature of the others not recorded. The hydro- 

 gen ion content of one pond only was measured, the PH value beinf 7.2. 

 April and October. 



11. CYCLOPS FIMBRIATUS Fischer 1858, 



Cyclopa fimbriatua, Herrick & Turner, '96. pp. 121, 122. pi. 17, Hg, 

 8, 9 ; pi. 21, fig:. 11 ; pi. 25, figr. 9-14. 

 This form is rare here, it having: been collected but once, June 1, 19(21, 

 when I obtained a few from a shallow temporary pond with a PH value 

 of 8.2. 



12. CYCLOPS FUSCA Jurine 1820. 



Cyclopa aignattu, var. coronatua, Herrick & Turner, '96. p. 106. pL 

 16. 

 I have always considered this a variety of C. albidua and have discussed 

 it under that head. 

 12. CYCLOPS PHALERATUS Koch 186S. 



Cyclopa phcUeratua, Herrick & Turner, '95. pp. 120, 121. pi. 17, llg. 



1-7 ; pi. 18, fig:. 2, 2d ; pi. 19, fig. 1 ; pi. 21, figr. 6-10. 

 Cyclopa phaJeratua, E. B. Forbes, '97. pp. 59-63. pi. 20, tig. S. 

 A few found on one occasion in a no-outlet pond, the temperature of 

 which was 82 'C. Also found in a weedy marsh with PH value of 8.2. 

 14. CYCLOPS LBUCKARTI, Claus 1867. 



Cyclopa levckarti, Herrick & Turner, '9«. pp. 96-98. pi. 16; pi. 18, 



ng. 1 a-J; pi. 24, f\g. 2-6. 

 Cyclopa edax, Forbes, '97. pp. 83-86. pi. 9, tig. 1-8. 

 Collected from three different localities in this district. Two were 

 ▼egetationlesa no-outlet ponds, the other a weedy marsh. The temperatun 

 of the water and the hydrogen ion content were determined for only one 

 locality, the temperature beinr 26 °C. and the PH value 7.8. May, June and 

 August 

 16. CYCLOPS, SERRULATUS Fischer 1860 



Cyclopa aerrulatua, Herrick & Turner, '9'5. pp. Ill, 112. pi. K, flff. 



S-11. 

 Cyclopa aerrulatua, B. B. Forbes, '97. pp. 64-67.pI. 17 ; pL II. 

 tig. 1-8. 

 One of the most widely distributed copepods in this district Found 

 throughout the season in all types of habitat, at all temperatures and In 

 waters with hydrogen ion content varying from PH 7.00 to PH 8.2. 

 16, CYCLOPS VIRIDI8 Jurine 1820, var. INSBCTUS Forbes 1882. 

 Cyclopa itiaectua, Forbes, '82. p. 649. pi. 9, fig. 6. 

 Cyclopa viridia, var. americanua, Herrick A. Turner, '9i6. pp. 91, 



92. pi. 14, fig. 1-9. 

 Cyclopa virUUa var. inaect%ia, E. B. Forbes, '97. pp. 41-44. pL 11. 



fir s-6. 



Perhaps the most common copepod in this district occurring In all type* 

 of habitat at all seasons and temperatures, and in waters with the hydro- 

 gen Ion content ranging from PH 7.0 to PH 8.2. This and certain spMlM 

 of Vortlcellidae and of one-celled yreen algae are often commensals. 



