COBB: A KEY TO THE GENERA OF FREE-LIVING NEMAS 463 



Dorsal pharyngeal wall not thickened; onchium a distinct projection (from preceding page) 

 Cephalic setae 20-30; cardiac glands conspicuous 

 Male supplementary organs complex; copulatory muscles conspicuous .... Xanthodora Cobb 1920 



Ce a ha!ic PI et ementS Simp ' P a P illoid : copulatory muscles not conspic. Acanthopharynx Marion 1870 

 Head with elaborately ornate calvarium; striae 0; spinneret present ....... Deontostoma Fil. 1916 



Head without calvarium; cuticular pores absent 



Plate round.with "bent" amph.;phar.smaU;ceph.set.4,cerv.oft long.many Diplopeltis Cobb 1905 



(=Dipeltis Cobb 1891 



. A = Discophora Villot 1875) 



Plate absent; pharynx large, complex, of more than 1 chamber; onchium large, sharp 

 Onchium conoid to base of short stylet; pharynx iquadrate; d" supplements eurystomoid 

 Long cervical setae 30; <? supplements weakly developed ....... . , . . . Ledovitia Fil. 1927 



Long cervical setae 



Tail rounded; spinneret oft present; d 1 supplements well developed.. .Eurystomina Fil. 1921 



( = Eurystoma Marion 1870 



=Marionella Cobb 1922) 



Tail spicate; spinneret 0; d" supplements weakly developed ...... Pareurystomina Micol 1930 



Onchium a long stylet; phar. much deeper than wide; d 1 an enchelid 

 Oesophageal bulbs 5-8, serial, contiguous ......................... Polygastrophora de Man 1922 



Oesophageal bulbs 

 Anterior oesophagus (pharynx ?) narrower, lumen wide ........... Calyptronema Marion 1870 



( = Catalaimus Cobb 1920) 

 Anterior oesophagus not differentiated 



Vestibule set off by row of "commas," pharyng. rings 3; eyes Symplocostomella Micol. 1930 

 Vestibule set off by rows of denticles or markings, or by a ring 

 Pharyngeal chambers behind vestibule more than 2 ............. Symplocostoma Bast. 1865 



Pharyngeal chambers behind vestibule 2; eyes 2 ........................ Dilaimus Fil. 1927 



( = Amphistenus Marion 1870) 



- Oesophagus with median or posterior bulb or swelling, or both (for alternative see page 461) 

 ^- Amphid not known or obscure (for alternative see next page) 

 Female not known 



Habitat soil;phar.tubular,i neck;onch.outward-acting;oes.dorylaimoid;spinneret Nanonema Cobb 1905 



( = Cephalonema Cobb 1893) 



Habitat marine; pharynx not over ,' neck-length; spinneret present (Rhinonema?) 

 Pharyngeal bulb stronger dorsad; onchium pharyngeal; cephalic setae small or 0. . ..lotadorus Cobb 1920 



Pharyngeal bulb absent; onchium a mere prod at lips; cephalic setae 6 ......... (Rhinonema Allgen 1927) 



"" Female known 

 Ovary 1 



Gonad 9 outstretched ;spinneret pres.;wings 10, marks V-shaped;ceph.set.4;marine (Nudora Cobb 1920) 

 Gonad 9 reflexed; spinneret absent; not marine 

 Onchium (spear) bent dorsad at tip; amphid small, oval, at lips; in soil ...... (Campydora Cobb 1920) 



Onchium not bent obliquely at tip 

 Cardiac bulb not valvate; median bulb strong 



Tooth recurved outward; long, striae present; c? supplements papilloid. .Diplogaster M. Schultze 1857 

 Tooth forward-pointing, deepset; long, striae none; d" supplements setose ---- Acrostichus Rahm 1928 



Cardiac bulb valvate; median bulb absent, oesophagus cephaloboid 

 Posterior pharynx muscular, lumen closed; vulva 75%; tail blunt ........ Plectonchus Fuchs 1930 



Posterior pharynx open; vulva 53-65%; tail conoid, usually slender 

 Vagina directed inward, not heavily muscular; not viviparous ........... Macrolaimus Maupas 1900 



Vagina directed forward, heavily muscular; viviparous or ovoviviparous ...... Turbatrix Peters 1927 



' Ovaries 



Gonads 9 outstretched ; pharyngeal bulb globular ........................... (Bolbolaimus Cobb 1920) 



(=B U lbopharyngiella Allgen 1929) 

 - Gonads 9 reflexed, exc. perhaps Demaniella. 



. 



Spinneret absent; oesophagus with muscular median bulb, usually valvate 

 Cardiac bulb valvate 



( = Diploscapteroides Rahm 1928) 



Lip region not set off; odontia absent Poikilolaimus Fuchs 1930 



Lip region set off by constriction; curved odontia 2 or 4 Rhabditis Duj. 1845 



Cardiac swelling not valvate, oesophagus diplogastroid 

 Onchium small, anterior; median bulb wide as long, wider than oesophagus Neodiplogaster Cobb 1924 

 Onchia larger, basal; "prod" at lips; median bulb not wider than oesophagus Demaniella Steiner 1914 



( = Demania Steiner 1914) 

 - Spinneret present; oesophagus without median bulb; wings often present; marine exc. Punctodora 



Lip reg. protrusile; ceph. set. 4; renette long; excretory pore opp. pharynx. .Ptycholaimellus Cobb 1920 

 Lip region not protrusile 



Pharyngeal swelling stronger dorsad; d* supplements chromadoroid exc. Odontonema 



Striae altered laterally; onchium large, dorsal, apex ventral Hypodontolaimus de Man 1886 



Striae not altered laterally 



Onchium solid, inward-pointing Prochromadora Fil. 1922 



Onchium with internal cavity, forward-pointing 



Tooth small . .V. Chromadorita Fil. 1922 f 



Tooth very large, apex ventral; d" supplements papilloid Odontonema Fil. 1930 



Pharyngeal swelling not stronger dorsad 



Cardiac bulb long, 2- or 3-parted; striae altered laterally; tooth large, forward-pointing 



The bulb with dilated lumen Spilopharella Fil. 1918 



The bulb with lumen not dilated; d 1 supplements chromadoroid Chromadorissa Fil. 1917 



Cardiac bulb short, not divided 



Striae altered laterally, several rows of dots larger Chromadora Bast. 1865 



Striae not altered laterally 



Onchium solid, inward-pointing; d" supplements chromadoroid Prochromadora Fil. 1922 



Onchium with internal cavity, forward-pointing 



Tooth small, sharp; d" supplements chromadoroid Chromadorita Fil. 1922 r 



Tooth large, irregularly rectangular; cardiac bulb very large, simple Punctodora Fil. 1930 



