Plate XXI. 



Tristojium sinuatum, 



Fig. 1. Median sagittal section of the anterior part of the body, x 73 diam. 

 „ 2. A small lateral portion of a horizontal section of the body ; to show the 



marginal sticky glands and their ducts, x 204 diam. 

 „ 3. A small lateral portion of a cross-section of the body ; to show the open- 

 ing of the marginal sticky glands, x 204 diam, 



4. A small ventral portion of a cross-section of the body, x 204 diam. 



5. A portion of a horizontal section of the body jnst behind the pharynx. 

 X 204 diam. 



„ G. Cross-section of the oviduct at the point of its junction with the ootyp ; to 



show the opening of the shell-glands, x 204 diam. 

 „ 7. Beginning of the yolk-duct, x 427 diam. 

 „ 8. •. Principal part of the female genital organs viewed as a transparent object 



from the ventral side. X 44 diam. 



