1. 



Phyllum NmATODA (Rud., I8O8) Cobb, 1919 

 (Key to the classes modified from Chitwood, 1950) 



1. Phasmids present, amphid openings pore-like, labial in position, 

 subventral esophageal glands never opening at or near anterior end 

 of the esophagus. Hypodermal and caudal glands absent. Caudal alae 

 or bursa and rectal glands commonly present. 

 SECERNENTEA (v. Linstow, 1905) Dougherty, 1958 P.l 



2. Phasmids absent, amphid openings spiral, circular, vesiculate, pocket- 

 like, tuboid or rarely pore-like, sublabial (not on lips). Bursa 

 absent except for Anoplostoma and Oncholaimellus ; rectal glands 

 usually absent. Hypodermal and caudal glands usually present 

 ADENOPHORA (v. Linstow, 1905) Chitwood, 1958 P. 75 



Class SECERNENTEA (v. Linstow, 1905) Dougherty, 1958 

 (Key to the orders modified from Chitwood, 1950) 



1. Esophagus simple cylindrical, or composed of a narrow muscular 

 anterior part and a wide glandular posterior part. Two or more well 

 developed labial structures; if three or six are present, they are 



reduced in size SPIRURIDA Chitwood, 1933 P. 2 



Esophagus divisible into three regions: corpus, isthmus, and bulbar 

 region. Lips usually 3 or 6 in number. 



2. Stoma not armed with a stylet, bulbar position of esoohagus with or 

 without sclerotized valvular apparatus. . . .RHABDITIDA Chitwood, 1933 P»3 

 Stoma armed with a protrusible spear or stylet, basal portion of 

 esophagus glandular without a sclerotized valvular apparatus. 

 TYLENCHIDA Thome 19li9 P.U 



