GROWTH OF THE FETAL CENTRAL NERVOUS SYSTEM 411 
3. FO: Fronto-occipital diameter; from the frontal pole to 
the occipital pole of the cerebral hemisphere. The frontal pole 
is defined as that point where the anterior, lateral, and inferior 
surfaces of the frontal lobes meet. In large brains, in situ, this 
Fig. 1 A figure representing the volumetric apparatus used in the collection 
of data. A, iron standard; B, clamp; C, stopper; D, wire; E, movable isinglass 
disk; F, bottle with spigot. The arrow indicates a hair line upon the wire. 
point is adjacent to the crista galli. The occipital pole is defined 
as that point where the posterior, lateral, and the interior sur- 
faces of the occipital lobes meet. 
4. TT: Temporal diameter; from the right temporal pole 
to the left temporal pole of the cerebral hemispheres. The 
temporal pole is defined as the most lateral point on the anterior 
