FIGURES 218 TO 221 



218 Same, section 20. 



219 Same, section 22. 



220 Same, section 26. 



221 Same, section 27. 



4 Atrophying embryonal vein, forming kernel in interior of developing 



and replacing lymphatic space. 



5 Extraintimal or perivenous lymphatic space surrounding degenerat- 



ing embryonal vein. 



