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 remarkable contributions to the
just understanding of the mammalian brain which has ever been made,
would have been the first to admit the insufficiency of his data had he
lived to profit by the advance of inquiry. The misfortune is that his
conclusions have been employed by persons incompetent to appreciate
their foundation, as arguments in favour of obscurantism. (80. For
example, M. l'Abbe Lecomte in his terrible pamphlet, 'Le Darwinisme et
l'origine de l'Homme,' 1873.)

But it is important to remark that, whether Gratiolet was right or
wrong in his hypothesis respecting the relative order of appearance of
the temporal and frontal sulci, the fact remains; that before either
temporal or frontal sulci, appear, the foetal brain of man presents
characters which are found only in the lowest group of the Primates
(leaving out the Lemur