6io 



FRESH-WATER BIOLOGY 



1-iG. 938. Apsilus bucinedax Forbes. 

 Ventral view. X65. (After Stokes.) 



Fig. 937. Stephanoceros eich- 

 hornii Ehr. X 60. (Alter 

 Weber.) 



Fig 939- Alrochus tenlaculatus 

 Wierz. X35- ( After Wierzejski.) 



Fig. 941. Acyclus in- 

 quietus Leidy. X 12. 

 (After Leidy, from Hud- 

 son and Gosse.) 



Fig. 940. Pompholyx 

 complanata Gosse. 

 X24S- (After Hud- 

 son and Gosse.) 



Fig 942. Pterodvna pattna Ehr. ,^- .I^^^f .u^mak ^(Aft'r 

 V o« (After Weber) B, Dorsal view of the male, ^mier 

 Sarki and w'eschS C\ Corona, showing the two wreaths of 

 cilia. (After Wesenberg-Lund.) 



