On the development and homology of the mammalian cerebellar fissures / by O. Charnock Bradley.

  • Bradley, O. Charnock (Orlando Charnock), 1871-1937.
Date:
[1903?]
Catalogue details

Licence: In copyright

Credit: On the development and homology of the mammalian cerebellar fissures / by O. Charnock Bradley. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    dieated in the 22 days embryo. Lobe C of the vermis usually carries eight folia, the majority of which are not carried directly into the hemisphere. The fissures between these folia are for the most part shallow, but two of them go to a greater depth than the rest, and are held to be of greater importance. Not only are they deeper than the others, but they appear at an earlier period. A reference to the 25 days embryo shows the fore- runners of these fissures as two pairs of depressions; one on the anterior, the other on the posterior slope. In the adult brain the more anterior of the two occurs between folia 2 and 3 (counting from fissure II.), and on being traced into the hemi- sphere is seen to run for some distance parallel to fissure II., into which it ultimately opens. For more immediate purposes we shall speak of this fissure as fissure b (fig. 24, b, fig. 28, b). An offshoot leaves it in the groove between vermis and hemi- sphere, and curves outwards and backwards to the border of the hemisphere. The other deep fissure of lobe C separates folium 6 from folium 7, and corresponds to the fissure resulting from the union of the pair of grooves on the posterior slope which first appeared on the 25 th day, and which met in the vermis two days later. This has already been referred to as fissure a. In the adult it can be traced to the outermost limits of lobe C. If we recognise the fissures just mentioned as being of importance, it follows that lobe C must be looked upon as consisting of three portions or lobules. These, for the present, will be called lobules Cv C2 and C3, starting the enumeration anteriorly. The fissure between lobes C and D (fissure III.) is of moderate depth in the middle of the vermis (fig. 28, III.), but becomes very shallow at its lateral borders. In some specimens, how- ever, there is not much difficulty in tracing its curved course outwards and upwards until it is lost in the deep fissure which separates the paraflocculus from the rest of the hemisphere. Lobe D is confined to the vermis, but in most specimens there is a low white ridge connecting it with the paraflocculus. Its surface is formed by three folia (sometimes a shallow fissure divides the lowest folium into two). Of the two fissures between these folia the lower is, slightly the deeper, and the lower folium extends rather farther towards the hemisphere