392 British Hydrachnidce : T/ie Genus Fiona. [Sess. 



With 3 swimming-hairs at distal end of each patella, and anus 

 within the small bay on posterior margin of plates. 



4. Fiona obturbans $ 



With the points of seminal pocket reaching both anterior and 

 posterior edges of genital plates . . .8. Fiona alata $ 



With 3 swimming-hairs at distal end of each patella. Genital 

 plates not extended so far as posterior point of fourth epimera, 

 with less than 12 acetabula on each plate . .15. Fiona mfa ^ 



With 3 swimming-hairs at distal end of each patella. Genital 

 plates extended just beyond the posterior point of fourth 

 epimera, with from 24 to 30 acetabula on each plate. 



7. Fiona rotunda $ 



Genital plates much more extended, with 30 to 35 acetabula on 

 each plate 6. Fiona rotundoides $ 



6. With 8 swimming -hairs at distal end of each patella. Large 

 wing-shaped genital plates, with a large number of acetabula. 



11. Fiona longipalpis $ 

 With only 4 hairs at distal end of each patella 22. Fiona elegans ^ 



