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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    taken the most prominent part of the convex border of the hippocampus major as the limit between the antero-median and the posterior portions of the cerebrum. The former includes the anterior and middle cornua of the ventricle, the corpus striatum, thalamus opticus, and the hippocampus major; the latter, the posterior cornu and hippo- campus minor, where these exist. In Man and the Quadrumana, the angle formed at the junction of the hippocampus major and minor readily indicates the exact spot on which to place the compasses (see Plate III. fig. 7). Such measurements should, if possible, be taken before the brain is removed from the cranial cavity. Let the length of the fii’st part be called A, and that of the second B. In Man the average proportion in several examples of A to B is as 100 to 53. In this Orang’s brain A measures exactly 2 inches, and B 1 inch, or as 100 to 50 ; so that the posterior lobe, as defined by internal structure, exhibits the same slight diminution upon that of the human brain, as was already esti- mated by the amount of covering of the cerebellum. It must be remembered, however, that this observation is taken from a spirit preparation. Preshytes leucoprymnus —An adult female died in the Zoological Society’s Gar- dens, August 20,1861, and the brain was examined while in a perfectly fresh condition. The posterior lobes completely covered, and projected beyond, the cerebellum. The sulci on the internal face of the cerebral hemisphere (Plate II. fig. 2) bear a very close resemblance in general arrangement (though of course far less complex) to those of the human brain. The occipito-parietal [Jc, k) runs downwards and forwards, and almost meets the calcarine (Z, Z), the second internal annectent gyi’us scarcely appearing on the surface. The calcarine sulcus difiers from tliat, not only of Man, but of nearly all Apes, in extending to the extremity of the lobe, and even turning round to the outer surface, without dividing into branches. The three sections show that this sulcus penetrates more deeply into the substance of the hemisphere than in Man, but it is tolerably simple in its course, passing nearly directly inwards. The posterior cornu of the ventricle is distinctly open to within a very short distance of the hinder extremity of the lobe, and is of considerable vertical depth, being curled round the very promi- nent calcarine involution, or hippocampus minor. In the left hemisphere a horizontal section was made, so as to expose the lateral ventricle (Plate III. fig. 5, a). The posterior cornu was seen, when opened from above, to take the same general course as in the brain of Man, viz. outwards, backwards, and finally somewhat inwards, but, owing to the depth of the calcarine fissure, and conse- quent great projection of the hippocampus minor, it is placed nearer to the external wall of the hemisphere than it is in Man. The measurements of the antero-median (A) and posterior (B) portions of the hemisphere are I *5 inch and '7 inch—A to B as 100 to 47. The latter is therefore proportionally less than in the human brain. CercopitJiecus.—Several examples of this genus have come under examination, in- cluding C. sabceus, C. ruber, and G. mona, but a description of C. pygerythrus (F. Cuv.), the common Vervet Monkey, will suffice. In order to obtain a side view of the brain in situ, the right half of the cranium of an adult animal of this species was carefully