On the posterior lobes of the cerebrum of the quadrumana / by William Henry Flower ; communicated by Dr. Sharpey.

  • Flower, William Henry, 1831-1899.
Date:
[1862]
Catalogue details

Licence: Public Domain Mark

Credit: On the posterior lobes of the cerebrum of the quadrumana / by William Henry Flower ; communicated by Dr. Sharpey. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    border of each lateral lobe. The extreme projection was T5 of an inch behind the cere- brum. In front the olfactory lobes extended of an inch beyond the cerebrum. The hemispheres were 1'65 inch in length, and 1'3 inch across their broadest part. On gently separating the edges of the longitudinal fissm’e, the corpus callosum was seen to cover completely the corpora quadrigemina; its length was -85 of an inch. The brain was now removed. The general surface of the cerebrum is smooth, but marked with strongly defined, deeply cut, regular, and almost symmetrical sulci. The anterior or frontal lobes are attenuated, being flattened above, compressed laterally, and excavated below for the orbital plates. They are distinctly marked off from the tem- poral lobe by the fissure of Sylvius, which runs upwards and backwards to the parietal region, and has an abrupt and slightly bifurcated termination. The average depth of this fissure is nearly one-foui'th of an inch, and on separating its lips, a small, smooth, but distinctly defined insula or median lobe of oval form was disclosed. This observa- tion is important, as Geatiolet says, “ Le lobe central [insula] parait particulier a I’homme et aux singes; peut-etre voit-on quelque chose d’analogue dans les makis, mais on ne voit rien de semblahle chez les autres mammiferes.” The temporal lobe is full and deep, and terminates posteriorly without any definite boundary in the posterior or occipital lobe. This last is shallow, and excavated on its under and inner surface for the cerebellum. The sulci on the outer face of the hemisphere are—1. The fissure of Sylvius {e\ 2. A well-marked longitudinal sulcus on the upper surface of the frontal lobe, inclining outwards posteriorly, probably corresponding with the infero-frontal (a). 3. A slight longitudinal indentation on the orbital surface of the same lobe. 4. A very distinct sulcus on the temporal lobe, parallel to, but extending rather higher than, the fissure of Sylvius, and curving forwards at its upper end (/*): this is the antero-temporal (scissure parallele). 5. A well-marked longitudinal sulcus on the upper surface of the parietal, and extending into the occipital lobe, marking off the upper limit of the angular gyrus. 6. A slight longitudinal indentation on the outer side of the occipital lobe. There is no trace of the temporo-occipital sulcus (scissure perpendiculaire ex- teme), so well marked in the higher Apes, or of either of the parietal fissures; indeed the region on which they should be placed is very greatly reduced. In number, extent, and situation the sulci above described nearly correspond to those of Callithrix moloch (as figured by Geatiolet), a Platyrrhine Ape about the same size as the Lemur. Upon the internal face of the hemisphere (Plate III. fig. 14) are seen—1. The calloso- marginal (^), distinct only in the middle third of the hemisphere. 2. A very deeply marked calcarine sulcus (Z, 1), extending from below the posterior end of the corpus callosum, backwards and slightly upwards, to near the extremity of the hemisphere, where it ends abruptly without bifurcation. 3. Joining this, almost at a right angle, is the occipito- parietal [Jc), which does not quite reach the upper margin of the hemisphere. 4. A slight indication of the collateral sulcus {n). 5. A well-marked dentate sulcus (m). The olfactory bulbs are in size intermediate between those of the lower Apes and