130 M. G. Sykes. 
of the bundle, a very considerable amount of xylem is present. Just 
below this point a space begins again to be visible, and those of the 
xylem elements which project into this space are of enormous size 
and of marked peculiarity (Text-Fig. 26, 1, 2, 4). In two cases 
(3 and 5) a single large tracheid was found entirely filling up the 
space. Sections below this region show that the space is the top of 
the carinal canal of the next internode and a gradual transition to 
the normal internodal structure now occurs. 
Fig. 26. 
