ge" described by Mivart (_Journ. Linn.
Soc_. vol. xix., 1886) (see fig. 22, _Sulc. Cru_.). In the higher apes
or Anthropoidea the human fissures and sulci are largely recognizable,
so that a gibbon's brain, apart from all question of comparative
anatomy, forms a useful means of demonstrating to a junior class the
main gyri and sulci of Man in a simple and diagrammatic way. The main
points of difference, apart from greater simplicity, are that the
central lobe or island of Reil is exposed on the surface of the brain,
as it is in the human foetus, and that the anterior part of the
occipital lobe has a well-marked vertical sulcus, called the simian
sulcus or _Affenspalte_; this often has a semilunar shape with its
convexity forward, and is then called the _sulcus lunatus_. It is
usually concealed in European brains by the overgrowth of the
surrounding gyri, but it occasionally remains, though less frequently
than in the brains of Egyptian fellaheen. Its relation to the _white
stria of Gennari_ is especially interesting, and is recorded by Elliot
Smith in the _Anatomischer Anzeiger_, Bd. xxiv., 1904, p. 436. The
rhinal fissure, which is so characteristic a feature of the lower
mammals, almost disappears in Man, and is only represented by the
_incisura temporalis_ (see fig. 11, _i.t_). The hippocampal fissure
persists with little modification all through the mammalian class. The
calcarine fissure remains with many modifications from the marsupials
to man, and in view of the famous controversy of 1864, in which Owen,
Huxley and the then bishop of Oxford took part, it is interesting to
note that its hippocampus minor can now be clearly demonstrated, even
in the Marsupialia. Another very ancient and stable sulcus is the
_orbital_, which is a simple antero-posterior line until Man is
reached (see fig. 23, _Sulc. Orb._). The great point of importance,
however, in the evolution of the mammalian brain is the gradual
suppression of the olfactory region, and the development of the
neopallium, a development which takes a sudden stride between the
Anthropoid apes and Man. (For further particulars of this and other
points in the comparative anatomy of the brain, see _Catalogue of the
Physiological Series_ of the Museum of the Royal College of Surgeons
of England, vol. ii. 2nd ed., by R.H. Burne and G. Elliot Smith,
London, 1902.)

[Illustration: From _Cat. R.C.S. En