3 CLASSIFICATION OF NEMATODES FILIPJEV 7 



Cuticle annulated or smooth. Bulb present or 

 absent. 

 (7) Cuticle annulated or smooth, without secreted rings 

 or setaceous appendages ; or if setaceous, then with 

 ordinary spiral amphids. 



Ovaries reflexed. Cuticle annulated. Free-living 



marine, fresh-water or soil forms Chromadorata 



Ovaries straight. Cuticle annulated or smooth. 

 Free-living, mostly marine forms Monhysterata 



Cuticle with 12 to 84 coarse secreted annules or 

 setaceous appendages. Amphids bubblelike. Free-liv- 

 ing marine forms Desmoscolecta 



8. (i) Tail without tail glands and spinneret. Amphids 



poorly developed, slit or papillalike, never pocket- 

 like. Saprozoic or parasitic. 



9. (12) Esophagus with a cardiac or middle bulb, sometimes 



degenerated or completely lost. Free-living, sapro- 

 zoic or parasitic. 



10. (11) Body without a large body cavity. Renette not very 



prominent. Free-living saprozoic or parasites of 

 invertebrates Angfuillulata 



11. (10) Body with large body cavity. Renette very prominent, 



with four large longitudinal ducts. Parasites of the 



intestines of vertebrates and invertebrates Oxyurata 



12. (9) Esophagus muscular or tubular, always well developed, 



without a bulb. Parasites of vertebrates. 

 Male with a well-developed bell-shaped bursa. 



Bursa with longitudinal ribs Anguillulata (Strongylidae) 



Bursa without ribs Dioctophymata 



Male without a bursa, or male absent in the parasitic 



stage. 

 Esophagus normal or with reduced musculature. 

 Head with three well-developed lips. Parasites of in- 

 testines Ascaridata 



19. (18) Head with two or four prominent lips or three obscure 



ones. 



20. (23) Parasites of intestines or respiratory system. 



21. (22) Head with three poorly developed lips or without lips. 



Parasitic generation syngonic; digenetic, free-living 



bisexual generation rhabditoid Anguillulata (Rhabdiasinae) 



22. (21) Head with two or four lips Spirurata 



23. (20) Parasites of tissues or circulatory system of verte- 



brates. Head with two lips or without lips. Esopha- 

 gus often without musculature Filariata 



24. (17) Esophagus tubular, consisting of one row of cells. 



Body very narrow, filiform in its anterior part Trichurata 



Order ENOPLATA 

 The Enoplata were defined by Filipjev (1918, 1927) primarily 

 as a family, and this was directly divided into several subfamilies. 



