.Ul. 



ovMiu-Ja,:dlv 'l'hIi-'YTA)lni.;,/> Oliit-Toor}, l';^/ 

 (Kej. to ramilion aftor Chibuood, ■.• Chituood, 19.^;o) 



1. Stona soi'iomiat reduced to rudiment.'ry; stomatal walls not, or poorly 

 scleroti'/ed 2 



3to!,:a well ae\/eloped; stoioatal walls well sclerotized 3 



2. Stoma conoid or collapsed conoid; esophago-intestinal valve bulb-like 



. . . TRIPYLID'^Ii; Oerley, 1880 P. Ill 



Stoma rudimentary; esophago-intestinal valve not bulb-like 



ALAVJDA'^. Micoletzky, 1922 p.ll?' 



3. Stoma capsule-form; esophageal gland orifices posterior to nerve ring 



. (Contains a single genus, Mon ouchus ) . . . MONONCHIDAF Chitwood, 1937 p. 115 

 Stoma cylindrical; esophageal gland orifices near base of stoma 

 ' IBDNIDAF de Man, I876 P. 119 



Family THIPYLIDAE Oerley, 1630 

 (Key to the genera after Fennak, 1953) 



1. Stoma a short, cylindrical cavity, about as long as head is wide 



Prismatolaimus de Man, I8B0 



Stoma somewhat conoid or obscure 2 



2. Lips massive, deeply cut, dividing head into three jaws 



Trischistoma Cobb, 1913 



Lips not massive, three or six, but head not appearing to be divided 

 into Jaws 3 



3. Stoma collapsed Tripyla Bastian, 1865 



Stoma conoid, divided Trilobus Bastian, 1865 



