THE FISSURA HIPPOCAMPI 2s 
4 E 
fon) 
Fig.4 The 27.8-mm. embryo, H 91, University of Chicago. X 12>. 
Fig.5 The 32.1-mm. embryo, H 41, University of Chicago. X 123. 
Fig.6 The 39.1-mm. embryo, H 165, University of Chicago. X 123. 
The levels from these various embryos are designated as follows: 1) through 
the lamina terminalis; 1 v) through the ventral part of the lamina terminalis; 
1 d) through the dorsal part of the lamina terminalis; 2) through the tela chori- 
oidea telencephali medii; 3) through the paraphysis. 
The various regions of the medial wall contiguous to the midline structures 
are self-explanatory, see the legend below the list of abbreviations. 
