218 KEY AND CHARACTERS 



PHARYNX ABSENT, or so obscure as easily to escape notice* New Genera 



Oesophagus with median or posterior bulb or swelling, or both 

 Amphids none, so far as known; or difficult to see and therefore easily overlooked 

 Lateral wings to cuticle present; naked; striae fine; spinneret none; pharynx obscure 

 Mouth depr.; faint apophyses in pharyngeal bulb; -f-; excretory pore behind neck.Hyalaimus 13 

 Mouth not depr.; pharynx obscure, not apophysate; oesophagus faintly cephaloboid 

 Head with papillae, minute lat. markings (amphids?) ; exert, pore front of nerve ring . Litonema 12 



Head without papillae or lateral markings; excretory pore behind the nerve ring Choronema 14 



Lateral wings to the cuticle none 



Spinneret abs.; naked; oesoph. faintly cephaloboid; striae very fine; faint wings . . (Choronema') 14 

 Spinneret present; cephalic setae present 



Amphids invisible, known only as outlets of secretion; striae coarse; setae long. (Leptoncmella) 21 

 Amphids tiny, tubular, labial, forward-pointing, easily overlooked; striae plain 

 Striae fine; male postanal tubular organs submedian ; pharyngeal swelling present. (Catanema) 56 



Striae coarse; pharyngeal swelling none; cephalic setae 4 or more; head nonstriate 

 Mouth cavity present, very small; males without supp. organs; nema 10mm. ..(Laxonema} 

 Mouth cavity none ; vent, row acornshaped organs toward head ; setae numerous . (Stilbonema) 



Amphids present 



Form of the amphids more 9r less irregular, symmetrical to at least one line 



The amphids linear ; cephalic setae 12 + 6 small ; striae coarse ; spinneret present . (Leptonemella) 21 

 The amphids not linear; no spinneret; naked; labial region with papillae only 

 Winged ; ' f ; striae rather coarse ; amphids semi-ellipses ; oesoph . faintly cephaloboid . lotalaimus 15 



Wings none; striae very fine; amphids with large internal connections Bolbinium 16 



Form of the amphids spiral, circular, or elliptical ; spinneret present 

 Shape of the amphids distinctly spiral; striae fine, resolvable 



Pharynx devoid of teeth; head expanded; cephalic setae 4; body setose Bplbonema 49 



Pharynx with 3 minute teeth; setae in longitudinal rows (Alaimonema) 107 



Shape of the amphids circular; sometimes small, well forward on the head, and obscure 

 Lateral wings present; cephalic setae 4; amphids large 



Striae coarse, altered on the lateral fields; lateral wing distinct Antomicron 17 



Striae fine, not altered on the lateral fields; lateral wing faint Cyartonema 18 



Lateral wings none or faint 

 External amphid circular, at least apparently, well developed; head set off 



Body setose ; amphids really spiral, on the head ; striae rather fine, resolvable (Bolbonema) 49 



Body naked; amphid circular 



Position of amphid, on head; striae fine; contour not crenate; wings faint (Cyartonema) 18 



Position of amphid, behind head; striae coarse; contour crenate Cincionema 22 



External amphid minute, on the front of the head, tubular, easily overlooked; neck 2-5% 

 Striae fine; male postanal tubular organs submedian; rjharyn. swelling present. . (Catanema) 56 

 Striae coarse, plain; cephalic setae 4 or more; head without striae 



Mouth cavity very small; nema 10mm; males without supplementary organs. . (Laxonema) 20 

 Mouth cavity none; cephalic setae in 3 or more circlets; males without caudal supplements 

 Supplementary organs of acorn shape, found in a ventral row near the head. . (Stilbonema) 1 

 Supplementary organs none, but with special pre- and postanal submed. setae . (Stilbonema) 19 

 Oesophagus plain, i.e. without median or posterior bulb or swelling of palpable size 

 Amphids none so far as known, or difficult to see and easily overlooked 



Wings 10-42; spinneret present; f=; striae fine, plain; ceph. setae 6, subceph. 4 Porocoma 11 



Wings 2, if any, lateral only, in any case faint 



Spinneret abs.; oesoph. faintly cephaloboid; striae very fine; no setae; faint wings. .(Choronema) 14 

 Spinneret present; amphids minute if any, unclosed 



Female organ single, -f ; 6 cephalic papillae only; spinneret doubtful; nema 0.28 mm. .Litotes 

 Female organs double, 'f; striae fine, plain; cephalic setae 4; 2 huge somatic glands. . (lonema) 9 

 Amphids present 



Form of the amphids more or less irregular, often symmetrical to at least one line 

 Contour of the amphids linear, i.e. long and narrow 



Lateral wings none ; cephalic setae 6, subcephalic 4 ; ' f Tycnodora 3 



Lateral wings present; head naked or its setae irregular; spinneret present 



Wings prominent; striae coarse; ' f ; inconspicuous pharynx (?) (Actinonema) 117 



Wings faint; striae fine; -f-; mouth oblique Campylaimus 5 



Contour of the amphids not linear 



Striae interrupted on the lateral fields by wings, plain 



Spinneret absent; oeosphagus faintly cephaloboid; 'f (lotalaimus) 15 



Spinneret present; oesophagus narrow, one to two-fifths as wide as neck 



Anterior extremity mitriform, very distinctly set off; wings to the cuticle 6-8 Xennella 



Ant. extremity not mitriform; coarse c'uticular elements in rows like tiles; ' f ' . . (Ceramonema) 48 

 Striae uninterrupted, fine, plain; spinneret present; slender nemas, up to 1.2% 



Head without setae; amphids relatively large and deep; not ocellate Schistodera 4 



Head with 4 cephalic setae; amphids small with obvious internal elements; ocellate . Nemella 10 

 Form of the amphids spiral, circular, or elliptical (doubtful in Litotes) 

 Shape of the amphids spiral; striae resolvable, not altered on the lateral fields 



Spinneret absent; striae coarse; probably f (?); contour crenate (Alaimella) 7 



Spinneret present; striae rather coarse; amphids large 

 Head expanded; lip-region elevated, not papillate; ceph. setae 6 plus 10; 'f'.. . (Nannolaimus) 36 



Head not expanded; lips 6, papillate; cephalic setae 4; f (?) Alaimella 7 



Shape of the amphids circular or elliptical; spinneret present except perhaps in Litotes 

 Lateral wings perhaps pres.; f ; striae plain; lipless; pharynx very minute, conoid. . Nemanema 2 

 Lateral wings none (or very faint); head rounded; striae none, or very fine 

 Cephalic setae ten or more, in two circlets 



Contour of amphids unclosed behind; setae 12, 4 subcephalic; mouth a mere pore . TMinium f 8 

 Contour of amphids closed; setae 10, no subcephalic ; pharynx minute, conoid. (Linhomoella) 35 

 Cephalic setae none, or small (4 or 6) 



Setae 4, small; ocellate; amphids small, labial, unclosed; body contains huge glands. lonema 9 

 Setae none; nemas of very simple structure; wings none or doubtful 



Papillae representing 6 setae; amphid (?) minute; -f ; nema 0.28 mm; width 5%. .Litotes 1 

 Papillae none ; amphids fairly developed, closed ; f ' ; nema 2.5mm; width 1 .4% . (Nemanema) 2 

 *For abbreviations used in the Key, see foot-note p. 223. 



