96 MARION HINES 
wall of the foramen. The vault is sealed by the tela chorioidea 
telencephali medii and the paraphyseal arch. The angulus ter- 
minalis has become still more obtuse. The dorsal portion of 
the lamina terminalis is no longer slender and ependymal; but, 
rather, growth in all directions so characteristic of this region in 
its ventral area has involved the whole of the terminal plate from 
the recessus preopticus to the angulus terminalis. The pars 
tenuis becomes less in extent as the pars crassa of the lamina 
terminalis increases in length. 
Looking into the ventricle, the lateral and medial limbs of 
the caudate complex are separated from each other by a shallow 
sulcus. The lateral component of this complex has increased 
in growth relatively more than the medial. The ventricular 
eminence formed by the fissura hippocampi upon the medial 
wall is broken in the region dorsal to paraphyseal arch, so that 
there is now an anterior and a posterior segment. The sulcus 
limitans hippocampi, lying ventral to this eminence, is continuous 
from the tip of the temporal pole to a region rostral of the lamina 
terminalis. The septal region lying between this sulcus and the 
angulus ventralis has grown in length and width, epecially in the 
ventral portion near its point of continuity with the diencephalon. 
The outer contour of the cerebral hemisphere is such that 
superficially the various poles of the adult hemisphere are recog- 
nized. The growth which has given this change in the surface 
is the result of increase in the tissue which is attached medially 
to the dorsal border of the hippocampus and laterally to the 
lateral limb of the caudate complex, namely, the neopallium. 
The most noticeable result of the growth of this tissue has been 
the swinging of the primitive caudal extremity, posteriorly, 
ventrally, and anteriorly. Thus the primordium of the temporal 
lobe is laid down. 
The fissura hippocampi is a shallow groove rostral to the 
lamina terminalis, while in the region above the paraphyseal 
arch it is barely visible. However, caudal to the velum trans- 
versum this fissure is deeper. Moreover, it follows the new 
direction of growth of the temporal lobe ventrally and anteriorly, 
so that its shape upon the free surface of the medial wall be- 
comes a semicircle. 
