Hydrachnellae 261 



2. With narrow subulate rostrum; chelicerae on the whole dagger- 

 like, without distinct separation between the claw and basal seg- 

 ment (fresh water forms) Hydrachnae 



Without narrow subulate rostrum; chelicerae not dagger-like, with 

 claws and basal segments distinctly separated from one another 

 (except marine forms) 3 



3. Genital suckers often very small, not lying on the plates or lobes, 

 nor under them, but free in the skin (then usually minute), or 

 more or less enclosed by sclerotic clasps (then frequently stalked 

 and acorn-shaped) ; eyes in eye capsules Limnocharae 



Genital suckers usually distinct, lying on or under the lobes or on 

 the plates or connected to sucker areas in the ventral armor (ex- 

 cept certain Fiona spp. with scattered discoidal suckers lying in 

 the ventral skin) 4 



4. Genital organ with movable valves or lobes 5 

 Genital organ without movable valves or lobes 6 



5. Genital suckers more or less knobbed, lying on lobes or united 

 with them, isolated when lying free Hydryphantae 



Genital suckers under or beside inner margin of lobes in region of 

 genital opening, not sclerotically united with lobes Lebertiae 



6. Palpi without apical claw between more or less spiniform palpal 

 segment v and distal end of broadened segment iv 7 



Palpi with apical claw between palpal segment iv (whose distal 

 margin more or less broadened and whose distal corner on the 

 curved side more or less drawn out forwards) and clawlike seg- 

 ment V Arrhenurae 



7. Genital organ with more or less distinct sucker plates and with 

 disklike or porelike suckers lying on them 8 

 Genital organ with swelling similar to lobes but firmly fused with 

 ventral armor; suckers, which are few, in region of genital opening 

 (except in Midea with sucker plates; palpal segment iv subulate 

 and reduced) Mideopsae 



8. Bodies generally with soft skin, rarely with more or less extensive 

 dorsal plates or still more rarely completely armored; palpal seg- 

 ment IV generally with frequently minute sclerotic process on 

 curved side at distal median corner Pionae 

 Body always armored, with narrow dorsal arch; palpal segment 



IV without sclerotic process on curved side at distal median corner 



Axonopsae 



