390 J. B. JOHNSTON 
Fig. 22 The thirteenth section of the same series drawn at a lower magnifica- 
tion. The section passes through the anterior pallial commissure and above the 
interventricular foramen. The heavy broken line shows the outline of the next 
section ventrad, in which the sulcus limitans hippocampi passes forward to enter 
the foramen. Note that the primordium hippocampi is followed caudally by the 
eminentia thalami and this by the ridge containing the tractus habenulo-peduncu- 
laris. The sulcus medius separates these two ridges. The anterior pallial com- 
missure in this section has only fibers connecting the hemispheres. 
