S98 



FRESH-WATER BIOLOGY 



B 



FIG. 905. Polychaetus collinsii 

 Gosse. X 250. (After 

 Jennings.) 



FIG. 906. Hydatina senta Ehr. A, Dorsal view of female. 

 , X 150. (After Weber.) B, Corona. (After Wesenberg- 

 Lund.) C.Trophi. (After Weber.) 



FIG. 907. Cyrtonia tuba 

 Ehrenberg. X 200. 

 (After Rousselet.) 



FIG. 908. Triphyfas lacustris Ehrenberg. X 134. (After Western.) 



