Plate XXIII. 



Teistomum ovale. 



Fig. 1. The whole worm viewed from the ventral side. The testes are represented 



only on one side. 

 „ 2. One of the hooks of the posterior sucker, x 70 diam. 

 „ 3. Tangential section of the marginal membrane of the posterior sucker. 



X 204 diam. 

 „ 4. Median sagittal section through the region of the pharynx, x 50 diam. 

 „ 5. Cross-section through the region of the left anterior sucker, x 50 diam. 

 „ 6. Cross-section through the anterior part of the pharynx, x 50 diam. 

 „ 7. A small portion of the ventral side of a cross-section of the body, x 204 



diam. The contents of the testes are only partially drawn. 

 „ 8. Central portion of the genital organs viewed as a transparent object from 



the ventral side, x 29 diam. 



