COBB: A KEY TO THE GENERA OF FREE-LIVING NEMAS 479 



Eyes 0; protrusile pharyngeal ribs 3, straight Fimbrilla Cobb 1905 



, .. ( = Fimbria Cobb 1894) 



Cephalic setae present, not papilloid (for alternative see preceding page) 

 Amphid shepherd's crook 



Annules not of tile-like elements Parachromagaster Allgen 1929 



Annules coarse, each of 8 tile-like elements Ceramonema Cobb 1920 



(cf. Pselionema Cobb 1933) 

 Amphid not shepherd s crook 



Nemawide;annules17,secreted annules obvious ;amph.saccate;ceph.set.4. .Desmoscolex Clap. 1863 

 Nema slender, under 5%; amphid not saccate; annules 0, striae fine or 0; Enoplidae 

 Onchium dorsal; labial setae 0; cephalic setae 10, near lips 



Tooth vestigial, on wall; external amphid a small slit; eyes (Anoncholaimus Cobb 1920) 



Tooth a bending inward of dorsal pharyng.wall;amphid larger.faint. . (Asymmetrella Cobb 1920) 

 Onchia none; labial setae 6, obvious; cephalic setae 10 or more, length 1-5 times head width 

 Pharynx narrow,closed;odontia (?) minute;ceph.set.3 times head width (Tubolaimella Cobb 1933) 

 Pharynx wide, open; odontia none 



Lips 3, deep-cleft, with frame work; ceph. set. 2-5 times head width Chaetonema Fil. 1927 



Lips without framework; ceph. set. 1 head-width; excret. pore raised. . (Paranticoma Micol. 1930) 

 External amphid spiral, circular or elliptical (for alternative see preceding page) 

 Female not known; spinneret present; marine 



Nema wide, 14-32%, widest at lip region, tapering to terminus; wings numerous. .Pteronium Cobb 1933 

 Nema slender, not over 5% wide, widest near middle 



Amphid multispire; wings 0; cephalic & labial setae 18; labial framework present. . . .Dispira Cobb 1933 

 Amphid circular, elliptical or monospiral 



Odontia 2, large, lateral or subventral (Diodontolaimus Southern 1914) 



Odontia absent(in Stephanolaimus 6 minute?) 



Onchium ventral ; cephalic setae 10; am ph. i head-width, with internal pocket. . (Isonemella Cobb 1920) 

 Onchium absent (Nudolaimus ?) 



Calvarium reduced to submed.plates;phar.large,wall strong/'onchia" basal. .Nudolaimus Allgen 1929 

 Calvarium absent; cephalic setae present 

 Wings present; cephalic setae 6 or 10 



Ceph. set. 6; wings 8; annules coarse, elements tile-like; oesoph. compound.. Dasynemella Cobb 1933 



( = Dasynema Cobb 1920) 



Ceph. set. 10; wings 2; oesophagus simple; pharynx iquadrate Pulchranemella Cobb 1933 



Wings absent; cephalic setae 4-8 



Lip region discoid, set off by constriction; odontia(?) 6 Stephanolaimus Ditlev. 1918 



Lip region not discoid; cephalic setae 4 or 6 



ng. vestibule with rod-like supports; head cylindroid; striae 0; ceph. set. 4 



6, straight, parallel to body axis; cephalic setae 4, jointed Rhadinema Cobb 1920 



Rods more than 6, curved, meeting axially Eleutherolaimus Fil. 1922 



Pharyng. vestibule without supports; striae pres. exc. Vasculonema & Bathylaimella 

 Amphid transverse-oval, near lips; head slightly conoid; setae small 



Setae labial, cephalic and subcephalic, minute Zygonemella Cobb 1920 



. Setae cephalic only, 6, small, inconspicuous Vasculonema Kreis 1928 



(cf. Pelagonema Cobb 1894) 

 Amphid circular, near base of wide-tubular pharynx 



Head cylindroid; setae on head 16, longest 4 times head width Cenolaimus Cobb 1933 



Head conoid, narrowing 50% from base; setae on head 4, short 



Cuticle striated; width (compressed ?) 6% Tubolaimus Allgen 1929 



Cuticle not striated; width 3% Bathylaimella Allgen 1930 



Female known 



Ovary 1 (for alternative see next page) 

 Gonad 9 reflexed 



Amphid multispire; ovary posterior; pharynx linear; spinneret doubtful; marine Alaimella Co,bb 1920 

 Amphid not multispire; ovary anterior 



Spinneret none; amph. round, with central mound; caudal setae thorn-like, 2 rows (Zanema Cobb 1920) 

 Spinneret present; tail without thorn-like setae 



Habitat marine; pharynx tubular; cephalic setae 4; nema 2% wide (Conolaimella Allgen 1930) 



Habitat not marine; pharynx open, not small nor narrow; nema 2-5% wide 



Cephalic setae 4 ; pharynx with supporting pieces; amph. monospire; fresh- water Anonchus Cobb 1913 

 Cephalic setae 6 or 10, papilloid in Tripylium 



Amphid monospire; in gills of land crabs (Tripylium Cobb 1920) 



Amphid small, circular, transverse-oval or slit-like 



Onchium 0; pharynx quadrate; amphid far back; in fresh water Prismatolaimus de Man 1880 



Onchium minute, deepset; pharynx conoid; amphid opp. pharynx; in soil (Trischistoma Cobb 1920) 

 Gonad 9 outstretched 

 Habitat not marine 



Spear minute; spinneret none; bursa present; parasitic in beetle (Aphelenchulus Cobb 1920) 



Spear absent; bursa absent; in fresh water Cylindrolaimus de Man 1880 



Habitat marine 



External amphid multispire; pharynx linear; tail 10%; spinneret doubtful (Alaimella Cobb 1920) 



External amphid circular, pocket elongate; tail 34%; spinneret none Halanonchus Cobb 1920 



The ovary anterior 



Cephalic setae 4, papilloid; pharynx obscure, linear; amphid faint, open caudad Litotes Cobb 1920 



Cephalic setae not papilloid 

 Spinneret absent; labial appendages ("palps") present; amphid circular 



Tail with 2 rows of thorn-like setae; amphid with distinct central mound Zanema Cobb 1920 



Tail without thorn-like setae; amphid without mound; cardiac bulb faint Crystallonema Cobb 1920 

 Spinneret present ; amphid circular or monospire 



Pharynx 7%, tubular ,halfway to nerve ring; head narrow ; amphid far back Rhynconema Cobb 1920 

 Pharynx less than 2%, not a long tube 

 Depth of pharynx much greater than width, pharynx small 



Oesophagus almost surrounding conoid pharynx Conolaimella Allgen 193 



Oesophagus meeting base of obconoid pharynx Sphaerocephalum Fil. 1918 



Depth of pharynx not much greater than width, pharynx large, open 



