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Dr. Cunningham—Surface Anatomy of the Primate Cerebrum. 27

altogether different genetic footing from the annular " Grundform " of the
mantle. He regards it as an accessory lobe (Nelenlappen) or accessory end
(Neoenende) of the hemisphere.

According to Ecker,* the occipital lobes do not exist in the third
month; they only appear in the fourth month. He applies the term
" Aussackung," or pouching out, to the process of formation. Panschf
speaks of the occipital lobe as a hinder " Auswuchs," which, taken along
with the context, clearly shows that he regarded the production of the
occipital lobe as due to local growth restricted to the hinder end of the
hemisphere. MihalkovicsJ calls the occipital lobe a " Nebenfortsatz," or
accessory projection, and frequently refers to the early condition of the
hemisphere in which, as he remarks, it only consists of frontal, temporal,
and parietal lobes. Krause§ applies the term " secundarer Auswuchs" and
11 secundare Bildung" to it; and Eichter,|| who, as we have seen, admits
the very early appearance of the calcarine and parieto-occipital fissures,
nevertheless speaks as if he regarded the budding-out of the occipital lobe
to be a process analogous to the outgrowth of the optic vesicle.

But, whilst the majority of anatomists would appear to take this view
of the formation of the occipital lobe, there are two who have expressed
themselves in very different terms. I refer to v. Kolliker and to His.
The opinion which v. Kolliker ^[ holds regarding the origin of the calcarine
and parieto-occipital fissures necessarily entails, as a part of it, the existence
from a very early period of a portion of the brain which corresponds to an
occipital lobe. His** gives an admirable account of the mode in which the
occipital lobe is moulded into shape. He explains that it owes its existence
to the strong development of the " Bruckenkriimmung," which, in the
primate brain, carries the cerebellum and pons downward and forward.

* Archiv f. Anthropologic, Dritter Band, 1869, p. 208.
f Ibid., p. 232.

\ Eutwicklimgsgeschichte des Gehirns, 1887, p. 111.

§ Handbuch der nienschlichen Anatomie, Zweiter Band, 1879, pp. 728, 729.
|| Archiv f. Path. Anat., Virchow, 1887, p. 421.

Entwickluugsgeschichte des Menschen und der hoheren Thiere, 1879.
** Unsere Korperforrn, 1875, Neunter Brief, p. 115.

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