CESOPHAGOSTOME^E 



439 



Group. CEsophagcstomese, Railliet and Henry, 1909. 



Bursa with anterior and median ray cleft (not double), postero- 

 .and postero-externaJ arising from a common trunk, posterior bifur- 

 cated, each limb bidigitate. 



Contains at present four genera : (i) Ternidens, (2) Chabertia, 

 (3) CEsophagostomum, (4) Agriostomum. 



FIG. 317. Mecistocirrus forai , bursa of male, dorsal view. The rays 

 are (i) postero-external, (2) median (= postero-median + antero-median), (3) 

 antero-external, (4) latero-anterior, (5) antero-anterior. These two latter are 

 parallel. The posterior ray is absent. (After Stephens.) 



Genus. Ternidens, Railliet, 1909. 



Buccal capsule sub-globular, opening obliquely in the dorsal surface, 

 and having at the bottom three complex teeth resembling those of 

 Triodontophorus. 1 Two crowns of leaflets ; peristomic collar moderate, 

 edge of bursa slightly toothed. 



Type. T. demimitus, Railliet and Henry. 



1 Triodontophorus belongs to the group Cylicostomca, which has the following bursal 

 formula: (i) anterior cleft, (2) median double, (3) postero-external and posterior arising 

 separately^ (4) posterior double, each branch giving off two lateral branches. 



