actual marmoset. No doubt it would be much more similar to the
brain of an advanced foetus of a marmoset. But we know nothing
whatever of the development of the brain in the marmosets. In
the Platyrrhini proper, the only observation with which I am
acquainted is due to Pansch, who found in the brain of a foetal
Cebus Apella, in addition to the sylvian fissure and the deep
calcarine fissure, only a very shallow antero-temporal fissure
(scissure parallele of Gratiolet).

Now this fact, taken together with the circumstance that the
antero-temporal sulcus is present in such Platyrrhini as the
Saimiri, which present mere traces of sulci on the anterior half
of the exterior of the cerebral hemispheres, or none at all,
undoubtedly, so far as it goes, affords fair evidence in favour
of Gratiolet's hypothesis, that the posterior sulci appear before
the anterior, in the brains of the Platyrrhini. But, it by no
means follows, that the rule which may hold good for the
Platyrrhini extends to the Catarrhini. We have no information
whatever respecting the development of the brain in the
Cynomorpha; and, as regards the Anthropomorpha, nothing but the
account of the brain of the Gibbon, near birth, already referred
to. At the present moment there is not a shadow of evidence to
shew that the sulci of a chimpanzee's, or orang's, brain do not
appear in the same order as a man's.

Gratiolet opens his preface with the aphorism: "Il est dangereux
dans les sciences de conclure trop vite." I fear he must have
forgotten this sound maxim by the time he had reached the
discussion of the differences between men and apes, in the body
of his work. No doubt, the excellent author of one of the most