PLATE XII. 



Fig. 22. Portion of a longitudinal section through the so-called cephalic lym- 

 phatic trunk of a 15-inch Polyodon. Note the papilla and the relative propor- 

 tion of white corpuscles to red. X450- Reduced |. 



Fig. 23. Transverse section through the jugular vein of a 15-inch Polyodon. 

 Note papilla here also and that the red corpuscles predominate. Outline sur- 

 rounding some of the corpuscles denotes plasma boundary. X 45o- Reduced \. 



148 



