micro cephalic icliot with bilateral porencephaly. 487 
on the lateral aspect of the occipital lobe : the retrocalcarine is 
thus continuous with the superior occipital sulcus. The inferior 
occipital sulcus cannot be identified with certainty. The cuneus 
is small, bub the paracalcarine sulcus can be recognised. The 
incisura parieto-occipitalis is distinct, but the sulcus limitans 
precunei is quite rudimentary. 
The temporal region. 
As has been already remarked, the lateral convex surface 
of the temporal lobe is only imperfectly convoluted. A mere 
groove deepening to a furrow behind, represents the first tem- 
poral sulcus, which joins the posterior limb of the fissure of 
Sylvius. 
On the inferior surface, no incisura temporalis remains. A 
shallow abnormal sulcus crosses the lobe obliquely from the interior 
outwards about 20 mm. from the temporal pole. Further back 
two sulci c6nverge and unite to form a representative of part of 
the collateral sulcus. There is no connection with the calcarine 
sulcus. 
The uncits is present, but small. 
The mesial aspect. 
The corpus callosum, fornix and uncus are not different from 
those of the right side, which have already been described (see 
under right hemisphere). But the fascia dentata does not come 
so clearly to the surface as on the right side. The longitudinal 
striae are unusually thick, but the little gyrus of Retzius is not 
so evident as it is in the right hemisphere. 
The optic chiasma remains attached to this (the left) hemi- 
sphere, and the optic nerves are seen to be unusually small. The 
left nerve is moreover distinctly smaller than the right. These 
facts are correlated with the defective cortical development, and 
here it may be mentioned that the left anterior corpus quadri- 
geminum is defective or at least smaller than the right. 
There is a long intercalary sulcus, in front of which are two 
genual sulci, while the intercalary sulcus is itself continuous with 
the rostral sulcus, limiting a broad gyrus subcallosus. Posteriorly, 
there are two compensatory sulci ; they are practically linear, 
almost parallel in direction and run obliquely upwards and 
backwards from near the splenium corporis callosi. 
Sectional Anatomy of the Cerebrum (Pigs. 8, 9, 10). 
The right hemisphere was divided in the coronal transverse 
planes corresponding respectively to \ , \ and f of its maximum 
