200 C. W. M. POYNTER AND J. J. KEEGAN 
Smith seems to have considered the sulcus prelunatus and the 
sulcus occipitalis lateralis identical, but the conditions found 
in this series of Negro brains will not permit of such an interpreta- 
tion. The more frequent method of forming the sulcus occipitalis 
lateralis is by a migration of one limb of the sulcus lunatus into 
line with the sulcus prelunatus proper, thus producing a long 
suleus which extends to a point near the occipital pole parallel 
to the lateral border of the hemisphere. Two of the inter- 
mediate forms can be seen in figures 1 and 3; in the first figure 
the sulcus lunatus has migrated almost to the occipital pole 
but still retains a perpendicular communication at its center 
with the elongated sulcus prelunatus. 
The sulcus occipitalis superior has been interpreted in this series 
as one or more sulci situated at or near the occipital pole between 
the sulcus lunatus and the bifurcation of the sulcus interstriatus 
mesialis, it might well be called the sulcus interstriatus lateralis. 
The typical Y-shaped form described by Smith is not found in. 
these brains, but a fairly constant and very prominent sulcus 
is found at the occipital pole which perhaps represents a meta- 
morphosed sulcus occipitalis superior. It is distinct in 46 per 
cent of hemispheres and has an average depth of 12 mm. There 
is frequently a shallow transverse communication with the sulcus 
interstriatus mesialis but this communication is evidently second- 
ary and does not represent the gyrus cuneo-lingualis posterior. 
The anterior lip is quite distinctly operculated which, taken with 
the operculum of the posterior lip of the suleus lunatus, would 
indicate a center of special growth activity in the lateral occipital 
region posterior to the lunate suleus. Other evidence of the 
growth activity of this area is found in the operculum of the sul- 
cus occipitalis inferior and the position of the sulcus occipitalis 
paramesialis on the mesial surface of the hemisphere. 
The sulcus temporalis superior presents interesting features 
in both its anterior and posterior portions. A separate anterior 
element has been described as the sulcus temporalis transversus, 
which can be identified in 65 per cent of these hemispheres. In 
some cases it has a shallow communication with the main sulcus 
as seen in figures 1 and 3, in other cases the sulcus temporalis 
