456 PROCEEDINGS HELMINTHOLOGICAL SOCIETY VOL. 2, NO. 1 



Vulva remaining functional; adult 9 parasitic; gubernaculum small 



Anus none or vestigial; in cucumber beetle, Diabrotica Howardula Cobb 1921 



Anus persisting; in frit-fly, Oscinella (Tylenchinema Goodey 1930) 



Ovaries 2; spinneret present exc. Micoletzkyia (for alternative see preceding page) 



Gonads 9 parallel, posterior; wings 10-12, segmenting the annules Parocoma Cobb 1920 



Gonads 9 opposed 

 The ovaries outstretched; marine 

 Annules few, very coarse; amphid saccate; cephalic setae 4; nema wide 



Number of annules 17, secreted annules prominent, separated; head small Desmoscolex Clap. 1863 



Number of annules 32-91 , secreted annules absent ; head concave-quadrate pyramidal. . Tricoma Cobb 1894 



( = Quadricoma Fil. 1922) 



Annules and striae 0; amphid not saccate; cuticle thick Phanodermella Kreis 1928 



The ovaries reflexed 



Habitat freshwater; lips 3, thick; pharynx narrow, deep; onchium minute, deepset (Tripyla Bast. 1865) 



( = Promononchus Micol. 1923) 

 Habitat marine; pharnyx and onchium absent 



Annules 17,secreted annules prominent ;amphid saccate;ceph. set. 4;nema wide Desmoscolex Clap. 1863 

 Annules not few nor coarse; amphid not saccate; nema slender 



Odontia 6; lip region discoid; ceph. set. 4; gland ducts oft piercing cuticle. . Stephanolaimus Ditlev. 1918 

 Odontia 0; lip region not set off 



Head set off by constrict.; ceph. set. 8; spicula long, slender; gub. complex Micoletzkyia Ditlev. 1926 

 Head not set off; cephalic setae 4 or 6 



Setae on head 4 ; eyes with lenses ; amphid transverse-oval, at lips ; among algae (lonema Cobb 1920) 



Setae on head 6 ; eyes none 



Spicula short, 1 anal body-diam.; pores 0; longest cerv. set. J neck-width. .Paroxystomina Micol. 1924 

 Spicula long, several anal body-diameters 



Cervical setae in 6 longitudinal rows; pores 0; ovaries equally long (Stenolaimus Marion 1870) 



Cervical setae 0; pores in dorso-sublat. rows; ovary post., anterior a rudiment. . Antopus Cobb 1933 



Amphid known (for alternative see preceding page) 

 External amphid not spiral, circular nor elliptical (for alternative i 



5 see next page) 

 Female not known; marine 

 Neck 40%;amph. narrow, several head- widths long;tail setaceous ;spinneret oft Halalaimoides Cobb 1933 

 Neck not over 25%; amphid not linear; spinneret present 

 Wings absent 



Odontia 6;lip papill. 6;ceph. set. 10(?) ; subceph. 4, jointed; amph. oval, flat caudad Apodontium Cobb 1920 

 Odontia 0; mouth & phar. vestigial; eyes, amph. & set. very large; adult cf only Enchelidium Ehrenb. 1836 



( = Lasiomitus Marion 1870 

 = Parasymplocostoma Schulz 1932) 

 Wings conspicuous 



Head mitreform, set off by constriction; striae 0; cephalic setae small, 4 or 6 Xennella Cobb 1920 



Head not mitreform, set off by lack of annulation; annules of "tiles" ; amph. crook-shape 

 Annules over 700; ceph. set. conspicuous, 8, in 2 circlets; onchia 0; nema 3 mm.+ Pristionema Cobb 1933 



Annules under 300; cephalic setae 4; onchium present (?); nema under 1 mm Pselionema Cobb 1933 



( = Steineria Fil. 1922) 

 (cf. Ceramonema Cobb 1920) 

 Female known 

 Ovary 1 



Gonad ? outstretched, anterior ;ceph. papill. 4;amph. minute, open caudad ;marine algae Litotes Cobb 1920 

 Gonad 9 reflexed 



Spinneret present; ovary posterior, anterior branch short; wings 0; marine Thalassoalaimus de Man 1893 

 Spinneret absent; ovary anterior; in soil about roots 

 Wings present, striae icoarse; cephalic papillae 4; amphid 1 head-width back. ..lotalaimus Cobb 1920 



Wings 0, striae 0; cephalic papillae minute; amphid 2 head-widths back Alaimus de Man 1880 



Ovaries 2 



Gonads 9 outstretched; spinneret present; marine 



Annules 17, secreted annules prominent ;amphid saccate ;ceph. setae 4 ;nema wide Desmoscolex Clap. 1863 

 Annules not few nor coarse; amphid not saccate; nema slender 



Mouth ventrad ; amphid huge, bent, dorsal limb the longer Campylaimus Cobb 1920 



Mouth axial; amphid not huge 



Amphid narrow, oft many head- widths long; eyes 0; cephalic setae 6, subceph. 4 Halalaimusde'M.a.n 1888 

 Amphid "folded," not over 1 head-width long; eyes 2, sometimes absent 



Oesophagus and lumen widened between eyes and nerve ring; pharynx obvious (Coinonema Cobb 1920) 

 Oesophagus and lumen not widened; pharynx like oesoph. lining. . . . Araeolaimoides (de Man) Fil. 1918 

 Gonads 9 reflexed 



Spinneret 0; tail 3%; ceph. set. 10, cervical long, 1 group at amphid; marine. . Platycomopsis Ditlev. 1926 



( = DactylonemaFil. 1927) 

 Spinneret present 



Habitat freshwater; lips 3, thick; pharynx narrow, deep; onchium minute, deepset (Tripyla Bast. 1865) 



( = Promononchus Micol. 1923) 

 Habitat marine; onchia absent ex<5. Actinonema 



Amphid narrow, several head- widths long; head set off, with colorless cuticle 



Cephalic & subceph. setae 1 head-width apart; cuticle thin (to ,'j radius) . . . Halalaimus de Man 1888 

 Cephalic & subceph. setae near together exc. Nuada isaitshikovi ; cuticle thick, to J radius 



The cuticle i to 1 radius in thickness Nuada Southern 1914 



The cuticle i to i radius in thickness Tycnodora Cobb 1920 



Amphid not narrow nor very long 



Shape of amphid a shepherd's crook ; each annule of tile-like elements Ceramonema Cobb 1920 



(cf. Pselionema Cobb 1933) 



Shape of amphid not a shepherd's crook; annules not of tile-like elements 



Annules 17, secreted annules prominent ;amph. saccate; ceph.set.4; nema wide Desmoscolex Clap. 1863 

 Annules not few nor coarse; amphid not saccate; nema slender 



Cutjcle 4 radius; striae coarse; amphid transverse, J head-width ; setae (Actinonema Cobb 1920) 



Cuticle not thick; amphid not a transverse slit; eyes with lenses; cephalic setae 4 



Amphidial gland large, conspicuous; cephalic setae 4, j head-width long lonema Cobb 1920 



Amphidial gland not evident; external amph. semicircular, internal elongate Nemella Cobb 1920 



