152 (s-s- 45-0 



THE MONONCHS 



Mononchus Bastian, 1866 



ay in pharynx or higher, usually massive 

 MONONCHUS Cobb; 



Subgenera 



and 

 Species 



1. MONONCHUS 



DORSAL TOOTH midw . _ , 



Tooth not opposed by denticles; subg. 



type, M. truncatus Bast.; pharynx about 2 to 3 times as 

 long as wide, goblet-shaped or ellipsoidal; wall smooth or 

 transversely striated; spinneret usually present; males of 

 about half the species known; female organs double (except 

 monhystera) 

 Dorsal tooth faced by 2 ventrally submedian teeth 



Teeth retrorse (tridentatus de Man 1876) 



Teeth not retrorse 



Tail conoid, then cylindroid; body 7 mm. long (rex Cobb 1904) 



Tail simply conoid; body 3 mm. long or less 



Spinneret and caudal glands absent exilis n. sp. 



Spinneret and caudal glands present . . 



Contour of the head angular; labial papillae 16 radiatus n. sp 

 Contour of the head rounded; labial papillae 12 



Pharynx longer than the head is wide palustris n. sp. 



Pharynx only as long as the head is wide teres n. sp. 



Dorsal tooth not faced by submedian teeth 



Ovary 1; pharynx not much longer than wide monhystera n. sp. 



Ovaries 2; pharynx toward twice as long as wide 

 Tail simply conoid, 8 per cent or less 

 Spinneret none 



Pharynx over half as wide as the head vorax n. so. 



Pharynx not over half as wide as the head 



Length about 1 mm.; tooth midway, small, digitate parvus de Man 1879 

 Length 1.5 to 2 mm.; tooth beyond midway, massive papillatus Bastian 1866 

 Spinneret present 

 Body 2 mm. long 



Form of the tail regular 



Form of the tail somewhat irregular 



Body 3 to 4 mm. long 



Tooth midway, amphids a little behind the lips maior Cobb 1893 11 



Tooth and amphids at the base of the lips gerlachei de Man 1904 12 



Tail conoid, then cylindroid, about 10 per cent or more 



(Esophagus 15 per cent fovearum (Dujardin) Bastian '66 13 



intermedius Cobb 1893 

 tenuicaudatus Stefanski 1914 



obtusus n. sp. 

 tunbridgensis Bastian 1866 



longicaudatus Cobb 1893 



2. SPORONCHULUS 



(Esophagus 22 per cent or more 



Buccal cavity toward 2 times as long as head is wide 



Spinneret armed with 2 very small setae megalaimus n. sp. 



Spinneret not armed with setae macrostoma Bastian 1866 



Buccal cavity only about half as long as head is wide 



Labial papillae setose 



Labial papillae, at least the outer, not setose 



Pharynx 54 as wide as head; body 1.5 mm. long 

 Pharynx */ 2 as wide as head or more; body 2 



to 3 mm. 



Cavity about 2 times long as wide; tooth acute truncatus Bastian 1866 

 Cavity about 3 times as long as wide; tooth 



sub-acute 



Inner labial papillae large; tail sub-conoid., dadayi Micoletzky 1904 

 Inner labial papillae normal; tail finally 



cylindric 



Tooth opposed by numerous denticles on opposite wall 



Arrangement of the denticles irregular; characters otherwise 

 as in Mylonchulus; subg. nov. SPORONCHULUS; 

 type S. dentatus n. sp. 



The tooth behind midway; spinneret present; anus at 92; 'f recessus n. sp. 

 The tooth in front of midway; no spinneret; anus at 96; 



Denticles about 20; pharynx half as wide as the head; T dentatus n. sp. 

 Denticles about 50; pharynx one-third as wide as the head 

 Arrangement of the denticles orderly 



Denticles along a ventral, longitudinal pharyngeal rib; 

 subg. PRIONCHULUS Cobb; type Pr. muscorum 

 (Dui.) Bast.; pharynx ellipsoidal, about 2 times long 

 as wide; males of one species known; female organs 

 double; no spinneret 



Eggs punctate or echinulate punctatus 



Eggs not punctate or echinulate 



Length 2.5 to 3.4 mm.; vulva at 65 per cent; anus at 

 94 per cent 



Width 3.6 per cent; denticles forward pointing muscorum (Duiardin) Ba 



Width 2.3 per cent; denticles inward pointing longicollis n. sp. 



Length 4 mm.; vulva at 55 per cent; anus at 97 per cent spectabilis Ditlevsen 1911 

 Denticles in transverse rows on 2 sometimes confluent, sub- 

 median, rasp-like areas, often with 2 very small sub- 

 median teeth at their bases; subg. MYLONCHULUS 

 Cobb; type M. minor Cobb; pharynx goblet-shaped, 

 tooth more or less arcuate; smaller species of which 



iecurrens n. sp. 



21a 

 21c 



3. PRIONCHULUS 



sp. 



'66 23 

 24 

 25 



