40. No corona; only a bunch of cilia about the mouth 



Philodinavus Harring 

 (Microdina Murray) 

 With one or more rings of cilia 41. 



41. Corona flat, regular 



Adineta Hudson 

 Corona in the form of two very distinct rings of cilia 42. 



42. No eyes 



Habrotrocha Bryce 

 (Callidina Ehrenberg) 

 With two eyes 43. 



43. Eyes far back in the neck 



Philodina Ehrenberg 

 Eyes very near the front 

 Rotaria Scopoli 

 (Rotifer Cuvier) 



44. No foot 45. 

 With a foot 50. 



45. With spines or jumping or swimming appendages 46. 

 Body saC'Hke, without appendages 48. 



46. With two or three spines 



Filinm Bory 



(Pedetes Gosse) 

 (Triarthra Ehrenberg) 

 With several branched or paddle-like appendages 47, 



47. Appendages branched 



Pedalia Barrois 

 (Pedalion Hudson) 

 Appendages paddle-like 



Polyarthra Ehrenberg 



48. Corona with two to four long bristles and wider than the body 



Synchaeta Ehrenberg 

 Corona without bristles, a little narrower than the body 49. 



49. Body transparent 



Asplanchna Gosse 

 Body colored or opaque 



Ascomorpha Perty 



50. Mouth in the center of the corona; with one toe or with two very unequal 



toes placed one dorsal to the other 5 1 . 



Mouth not in the center of the corona; with two equal or nearly equal 



toes side by side 52, 



51. Foot about as long as the body; eye usually purple 



lAicrocodon Ehrenberg 

 Foot shorter; eye usually red 



Mi/^rocodides Bergendal 



71 



