602 



FRESH-WATER BIOLOGY 



FIG. 914. Eretmia trithrix Gosse. 

 (After Gosse.) 



FIG. 9 1 6. Nothpl- 

 ca longispina 

 Kellicott. X 

 170. (After 

 Weber.) 



FIG. 915. Gastropus hyptopus Ehr. 

 X 170. (After Hudson and Gosse.) 



FIG. 917. Gastropus stylifer 

 Imhof. X 200. (After 

 Weber.) 



FiG< 918. Ploesomalenticulare 

 Herrick. X 300. (After 

 Wierzejski and Zacharias.) 



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

 Wierzejski and Zacharias.) 



FlG. 920. Ploesoma truncatum Le- 

 vander. X 160. (After Weber.) 



