6o2 



FRESH-WATER BIOLOGY 



Fig. 914. Eretmia trithrix Gosse. 

 CAfter Gosse.) 



Fig. 916. Nothol- 

 ca longispina 

 Kellicott. X 

 170. (After 

 Weber.) 



Fig. 917. Gastropus stylifer 

 Imhof. X 200. (After 

 Weber.) 



Fig. 915. Gastropus hyptopus Ehr. 

 X 170. (After Hudson and Gosse.) 



Fig. 918. Ploesomalenticulare 

 Herrick. X 300. (After 

 Wierzejski and Zacharias.) 



Fig. 919. Ploesoma hudsoni Imhof. X 150. (After 

 Wierzejski and Zacharias.) 



Fig. 920. Ploesoma truncatum Le- 

 vander. X 160. (After Weber.) 



