10 Trims. Acad. Sci. of St. Louis 



FAMILY MACROTHRICIDAB 

 GENUS ACANTHOIiEBERIS LILLJEBORG lft5S 

 26. ACANTHOLEBBRIS CURVIROSTRIS (O. F. Mueller) 177« 



Acantholeberis curviroatris, Herrick & Turner, '9>5. p. 21t. pi. 4/9, 

 fig. 1-4, 

 Rare or accidental in this district, a few havingr been found in a weedy 

 pond on one occasion. 



GENUS MACROTHRIX BAIRD 184S 



26. MACROTHRIX L.ATICORNIS (Jurine) 1820 



Macrothrix laticomiSj Herrick & Turner, '95. p. 212. pi. S4, flc> 

 9-12; pi. 56, fig. 8, 9. 

 Found in four different localities in this district; in a marsh, anions 

 the water plants in a lake, in a no-outlet permanent pond, and in a transi- 

 tional pond, the bottom of each being mud. The temperature range of the 

 water was 14-31''C. The hydrogen ion content was determined for only 

 three of the localities; for two it was PH 8.2 and for the third PH 7.2. 

 In the marsh and lake only a few specimens were found ; In the transitional 

 pond it was abundant. April, May, June, and Augrust. 



FAMILY SIDIDAE 

 GENUS DIAPHANOSOMA FISCHER 1850 



27. DIAPHANOSOMA BRACHYURUS (Lievin) 1848 



Daphnella brachyura, Herrick & Turner, '96. pp. 148, 149. pi. tt, 

 tig. 11-16. 

 In July, 1920, this was common in a transitional pond with muddy 

 bottom, in a St. Louis park. The temperature of the water was ZO'C. 



28. DIAPHANOSOMA LEUCHTENBERGIANUM FISCHER 1850 



Daphnella brandtiana, Herrick & Turner, '96. p. 149. pi. 37, tig. 3-6. 

 In June, 1920, this species was abundant in a temporary pond near 

 Koch, Mo. The water was muddy and free from vegetation, with a tem- 

 perature of 30 "C. 



GENUS LATONOPSIS SARS 1888 



29. LATONOPSIS OCCIDENTALIS Birge 1891. 



Latonopaia occidentalia, Birge, *91. pp. 383-3'88. 



Latonopaia occidentalia, Herrick & Turner, '95. pp. lBO-1'51. pi. 38 

 Collected in June, 1920, from a small permanent pond near Jefferson 

 Barracks, Mo. The bottom was muddy and the pond held no vegetation, 

 the water itself being clear. 



GENUS PSEUDOSIDA HERRICK 1884 

 80. PSEUDOSIDA BIDENTATA Herrick 1884. 



Paeudoaida tridentata, Herrick & Turner, •9'5. pp. 147, 148. pi. 86, 

 tig. 2-6 ; pi. 50, fig. 9. 

 In June, 1910, a few specimens were collected from a swamp near Union 

 Avenue and Natural Bridge Road, St. Louis. 



Succession op Life in a Tbansitional Pond 

 A transitional pond is one which is dry during part of 

 the year, but which, during periods of high water, is con- 

 nected to a permanent pond or lake. 



It is not the purpose of this section to give an exhaus- 

 tive treatment of the succession of entomostracan life in 

 ponds and lakes but, by discussing the succession of clad- 

 oceran and copepodan life in one transitional pond for 



