280 H. SAXTON BURR 
optic recess, as Johnston indicated, but in the terminal ridge. 
By this fact it may be seen that the terminal ridge marks the 
rostral limit of the roof plate of His. 
Fig.6 Graphic reconstruction from sagittal sections of brain of embryo shown 
in figure 5. X 50. chr., chiasmatic ridge; ep., epiphysis; rn., neuropore; sl., 
sulcus limitans; tr., terminal ridge; vt., velum transversum. 
Fig. 7 Transverse section through the head of an 1l-mm. Amblystoma 
embryo, showing the general relations of the lamina terminalis.  X 50. 
Fig.8 Transverse section 190mu caudad of figure 7, showing the general rela- 
tions of the median alar plate. > 50. 
Fig.9 Transverse section 110w caudad of figure 8 passing through the cbias- 
matic ridge.  X 50. 
