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Me. Victor Hoesley—Cranio-Cerebral Topography.

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guide to the localization of the upper limit of the fissure [i. e. its vertical
stem). On this point it should be mentioned that where the rare case of no
definite focus of subdivision exists, the point taken lies in the bregmatico-
auricular line.

In order to obtain a further assistance, I examined in the adult the
relation of the stephanion to the prrecentral sulcus. In the exceptional
instances in which the sulcus coincided with the coronal suture the stephanion
lay nearly over the bifurcation point of the sulcus, and further,
that where the sulcus lay behind the coronal suture, the temporal ridge,
traced backwards beyond the stephanion, would, in most cases, be found to
pass over the particular point. As a confirmatory guide this line is consequently
useful. (See Plate VII.) Of course this only applies to the head
after puberty.

Sulcus Prcecentralis Superior.—This sulcus, which, until the writings of
Jensen, was regarded as simply the hinder end of the superior frontal
sulcus, occupies an extremely constant position. It presents practically
the shape of a T lying horizontally, the cross arms being at right angles
to the margin of the hemisphere.

The horizontal part or stem of the T joins with the superior frontal
sulcus, and will be considered directly.

The present point to decide is the position and extent of the superior
prsecentral sulcus. Its antero-posterior position on the outer surface is
easily found. If a line be drawn upward in the direction of the sulcus
pivTcentralis inferior to the sagittal suture, then the sulcus prascentralis
superior will be found to lie midway between this line and the fissure of
Eolando. It thus lies, as it were, in the ascending frontal gyrus, notably
diminishing the breadth of this convolution in its upper part. The next
fact relating to its topography is the determination of its greatest extension
downwards. This is a significant matter, inasmuch as the lower end of
this sulcus comes into close relationship with the inferior genu of the fissure
of Rolando, and consequently it approaches the delimitation level of the
respective representations of the upper limb and face.

To obtain an accurate index of the mean position of the lower end of
this sulcus I have taken as a basis line the distance from the sagittal suture

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