220 KEY A.ND CHARACTEES 



Oesophagus with median or posterior bulb or swelling, or both 

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

 Lateral wings present; spinneret absent 



Striae none; wings 2; naked; pharynx like oesophagus lumen (Litonema) 12 



Striae fine; wing 1; seta-like papillae 6; pharynx contains glottoid organ Cephalobium 54 



Lateral wings absent; striae plain 

 Spinneret present 



Striae very coarse; phar. cupshaped; nema 10mm; male, no supplement, organs. (Laxone.ma) 20 

 Striae fine; phar. small, enclosed in bulb; male postanal tub. organs submedian. . (Catanema) 56 

 Spinneret absent; setae none 



Phar. very long, nar., ending in cylindroid bulb; 'f'; nema 1mm; lips conoid Myctolaimus 61 



Pharynx very short; cardiac bulb oblate or spherical; f" 



jNema 3.3mm; width 9%; pharyngeal apophyses present; oesophagus clavate .Blattophila 55 

 Nema 6mm; width 3%; pharyngeal apophyses absent; oesophagus cylindrical. Protrellus 38 

 Amphids present. 



The amphids are somewhat irregular, symmetrical to one line; striae fine, plain; wingless 

 Form of amphids not lin.; no spinneret; naked; lips 6; phar. tub.; amphids large. Colpurella 39 

 Form of amphids linear 



Ovary one, 'f ; spinneret absent; cephalic setae 6 plus 4; pharynx tubular. . . . (Myolaimus) 60 

 Ovaries two, -f-; spinneret present; ceph. setae 4; ventral (?) onchus near mouth. Pseudolella 53 

 The amphids are spiral, circular, or elliptical 

 Shape of the amphids a distinct spiral 



Striae coarse; oesoph.=toxyuroid; wings 8; ceph. setae 6, subceph. 4; head unstr. . (Dasynema) 34 

 Striae fine 



Lateral wings present; striae plain; spinneret present; head thick-walled. . . .Pycnolaimus 40 

 Lateral wings absent 



Spinneret none; -f-; cephalic setae 10, subcephalic 4; pharynx obscure Laimella 44 



Spinneret present 



Phar. armed in front with 3 obscure equal teeth; setae numerous on head. . (Alaimonema) 107 

 Pharynx without teeth ; head rounded 



Lips 2, lateral; 'f; striae plain; pharyngeal ridges simulating teeth (Pseudonchus) 58 



Lips none, or very indistinct 



Cephalic setae 10. subcephalic 4; pharynx obscure, has minute onchus Laimtlla 44 



Ceph. setae four ? (or none); lips set off; phar. 2-chamb., 2d tapering (Polylaimium) 59 



Shape of the amphid circular or elliptical (anon tubular) ; striae unaltered laterally 

 Spinneret absent; striae plain, fine 



Ovary one, -f ; ceph. setae 10, subceph. 6; amphids circular; pharynx broad. (Crystallonema) 67 

 Ovaries two 



Cuticle naked; spear (?) minute; ceph. setae 0, 6 pap.; amphids ellip.; T. . (Tripltmchium) 80 

 Cuticle not naked; without spear; ceph. setae present; amphids circular; -f-. Anticyathux 24 

 Spinneret present 



Buccal cavity very small and easily overlooked; cephalic setae present; striae plain 

 Striae coarse; phar. minute, cupshaped; males without supplementary organs , Laxonema 20 

 Striae fine; phar. narrow, bulbed; males with postanal rows of tubular organs. Catanem a 56 

 Buccal cavity very long; 'f; striae fine; cephalic setae small or none 

 Cephalic setae four (?) or none ; amphids large, deep ; pharynx 2-chambered. . . Polylaimium 59 



Cephalic setae 10, short; amphids small; ocellate; pharynx very long (Catalaimus) 89 



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

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



Wings present; spinneret present; striae fine; ovaries two, f=; phar. vestigial. .(Porocoma) 11 

 Wings absent; striae fine 



Ceph. setae 10, long, segmented; lips 6, thin, each with seta; amphid minute slit. . (Trilepta) 92 

 Cephalic setae none, or not long or obviously segmented; lips without setae, or lipless 

 Buccal cavity tubular; spinneret absent; 'f; lipless; papillae depressed. ... (Isolaimium) 41 

 Buccal cavity not long and tubular; spinneret present 

 Ceph. setae 10; lips 6, obvious; dorsal phar. element bent in at lips; 'f (?) . . (Asymmetrella) 70 



Cephalic setae 6, papilloid; lipless; -f (Litotes) 1 



Amphids present 



Structure of the amphids more or less irregular, usually symmetrical to at least one line 

 Contour of the amphids linear; striae not altered on the lateral fields 



Ceph. setae long, segmented; lips 6, thin, each with seta; amphid minute slit. .(Trilepta) 92 

 Cephalic setae none, or not long and not obviously segmented 



Spinneret absent; 'f; striae fine; phar. tub.; lips confluent; papillae depressed. .Isolaimium 41 

 Spinneret present; female sexual organs double; striae fine 



BUG. cavity tub.; amphids long; striae resolve; onchus ventral (?), obscure. . (Pseudolella) 53 

 Buccal cavity not tubular; amphids more or less stirrup form; striae not resolvable 



Ocellate; cephalic setae none; lips faint; amphids distinct, though small (lllium) 45 



Ocelli 0; setae 10; cutinized dorsal pharyn. element bent inward at lips. . (Asymmetrella) 70 

 Contour of the amphids not linear 

 Striae altered on the lateral fields; ovaries two, reflexed; spinneret present 



Lateral wings present; striae coarse, like rows of tiles; pharynx narrow Ceramonema 48 



Lateral wings none; striae fine, plain; onchia vestigial; six cervical glands. (Anoncholaimus) 93 

 Striae not altered on the lateral fields, fine 

 Spinneret none 



Cephalic setae 4, forward-pointing; amphids more or less deltoid (Didelta) 33 



Cephalic setae 0; amphids more or less reniform Colpurella 39 



Spinneret present 



Cheeks thickly cutinized; head conoid; small forward-pointing onchia (?) . (Isonemella) 109 

 Cheeks not thickly cutin.; head not prom, conoid; no small onchia exc. in Anoncholaimus 

 Ovaries outstretched, -f-; ocellate; phar. tubular; nearly lipless; ceph. setae 4. (Coinonema) 42 

 Ovaries reflexed, 'f; striae fine, plain; pharynx not tubular; head truncate 



Cephalic setae none; ocellate; lips faint; amphids distinct, though small lllium 45 



Cephalic setae 10; ocelli none; amphids indistinct 



Dorsal cutinized element of the pharynx bent inward at the lips (Asymmetrella) 70 



Dorsal wall of the pharynx not differentiated; onchia minute (Anoncholaimus) 93 



Structure of the amphids spiral, circular, or elliptical 



