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Dr. Cunningham—Surface Anatomy of the Primate Cerebrum. 233

Of the more recent workers at the surface anatomy of the human
cerebrum there is no one who has shown a keener insight into the conditions
present, or a more judicious appreciation of the homologies which
exist between the convolutions and sulci in man and those in the apes, than
Eberstaller of Graz.* We have already noted that he does not claim that
the sulcus transversus of Ecker is the homologue of the " Affenspalte" in
the apes—merely, the u analogue." What he exactly means by this I am
unable to understand, more especially as he applies the term " Affenspalte'
to the sulcus transversus in the human brain. Further, he appears to draw a
distinction between the upper and lower limbs of the sulcus occipitalis transversus
of Ecker. Thus he remarks : "In it we can distinguish a medial and
a lateral segment by the point of junction with the sagittal portion of the
interparietal furrow; the former bounds the arcus parieto-occipitalis (the
first annectant gyrus) behind, without, in the majority of cases, reaching
the mesial border, the latter is the sharply descending end of the arch-like
fissura interparietalis."f In the abstract which I published in the Journal
of Anatomy and Physiology of this chapter (Vol. xxiv.), and which was
written before I had become acquainted with all the work which Eberstaller
has done in this field, I expressed myself in somewhat similar terms. I
contended that the lower part of the sulcus transversus was the representative
of the down-turned extremity of the ramus occipitalis of the intra-
parietal sulcus, and that it was possible that the upper part had some
connexion with the " Affenspalte." As will be seen from what goes before,
a more extended study of the question, and a great addition to the number
of my specimens, have led me to believe that the entire sulcus occipitalis
transversus of Ecker is quite independent of the "Affenspalte" of the apes,
and has, in point of fact, nothing to do with it whatever.

Eberstaller very rightly disputes Ecker's assertion that the posterior lip
of the sulcus transversus occipitalis in the human brain projects forwards in
some cases so as to overlap the anterior lip in the form of an operculum.
He says: "I have examined the 1 Affenspalte' X in from two to three

* Wiener Medizinische Blatter, No. 19, 1884, p. 582.
f Wiener Medizinische Blatter, No. 18, 1884, p. 548.
| By this he refers to the sulcus occipitalis transversus of Ecker.

ROYAL HUSH ACADEMY.-CUNNINGHAM MEMOLKo, NO, VII. [30]