SULCUS LUNATUS 13) 
to which a fissure must conform in order to be recognized as 
an indubitable sulcus lunatus. In order to discuss this question 
more fully I will review shortly the opinions that have been 
expressed by recent investigators on this subject. 
In 1903 Elliot Smith described a sulcus in the human brain, 
homologous to the so-called ‘Affenspalte’ of apes, to which he 
gave the name ‘sulcus occipitalis lunatus’ (3). The evidence 
S.cent. 
S.interpar. 
Fos.par.oce, 
S.occ.trans. 
S.prael. S.lun, 
S.occ. inf. S.occ, S.par.oce, 
S.calc.ext. 
S.occ.trans. 
S.calc.ext, 
2 3 
Fig. 2 Same preparation as in figure 1 seen from behind. S. calc. ezt., lateral 
calearine sulcus; fos. par. occ., fossa parieto-occipitalis, in which is seen the ex- 
posed summit of the gyrus intercuneatus. Other lettering as in figure 1. 
Fig. 3 Posterior view of right cerebral hemisphere, which was exposed by a 
later dissection. Lettering as in figures 1 and 2. 
upon which this conclusion is based is twofold: first on account 
of the essential similarity of the sulcal pattern in certain primitive 
Egyptian brains and in the brains of the great anthropoids; 
and second because in apes the lunate sulcus forms the definite 
anterior limit of the area striata on the lateral surface of the 
occipital region, while in the Egyptian brains, though not in- - 
variably the case, this condition is not infrequently met. Since 
that time a very voluminous literature, much of it being of a 
