104 MR. FLOWER ON THE BRAIN OF THE JAVAN LORIS. 
rupted in the middle line by a slight divergence from each other of the occipital 
extremities of the hemispheres, distinct even before removal from the cranial cavity. 
The sulci, though few, are well marked and tolerably symmetrical. The general surface 
of the brain is very uneven, being raised into strongly pronounced, sinuous gyri, the 
impression of which is very distinct on the inner surface of the calvarium. There is no 
appearance of that want of symmetry both of size and form, in the two hemispheres, 
described and figured by Vrolik. Projecting anteriorly to the extent of one-fifth of an 
inch beyond the cerebral hemispheres, are the olfactory lobes, of considerable vertical 
depth, but compressed laterally and pointed in front. Projecting posteriorly is a very 
narrow edge of the cerebellum, most visible in the middle line, both on account of its 
own greater prominence at this part, and because the widening out of the termination 
of the great longitudinal fissure of the cerebrum allows more of its upper surface to 
be seen. 
When seen from one side, the upper contour of the brain forms a low flattened arch, 
the greatest point of elevation being a little way behind the centre (fig. 3). The anterior 
or frontal lobe is much depressed, and excavated below to make room for the orbital 
plates of the frontal bone. The temporal lobes, distinctly marked off from the last by 
the Sylvian fissure, are moderately full, and make a well-marked projection downwards 
and forwards. The occipital lobes are short and of little vertical depth, being hollowed 
below for the cerebellum, the greater part of which they cover. 
The sulci of the cerebral hemispheres are' :—A. On the outer face (figs. 1 & 3). 1. The 
fissure of Sylvius (e, e), distinctly marked, directed obliquely upwards and backwards 
to the middle of the upper surface of the hemisphere, where it makes a slight change 
in direction, continuing to extend backwards, but almost parallel to the great longi- 
tudinal fissure. In the first portion of its course, it is as nearly as possible parallel to 
the inferior margin of the temporal lobe. It divides the whole hemisphere into two 
tolerably equal parts, the anterior containing the frontal and parietal, the posterior the 
temporal and occipital lobes. On separating its lips, no distinct median lobe, or 
insula, could be traced. 2. A distinctly marked sulcus (f) on the temporal lobe, 
posterior and parallel to the last, corresponding to the ‘‘ antero-temporal” of the 
higher Quadrumana (‘‘scissure paralléle’’ of Gratiolet). 3. A small sulcus running 
in a transverse direction on the upper surface of the hemisphere, at the junction of the 
parietal and occipital lobes, recalling the ‘‘ temporo-occipital ” (scissure perpendiculaire 
externe) of the Quadrumana, which fissure is, however, wanting in the smaller American 
Apes, as in Lemur. Anterior to the fissure of Sylvius are three small and straight 
sulci, all placed longitudinally, at different levels, the first on the upper, the second on 
the outer, the third on the lower (orbital) surface of the hemisphere. The two former 
may be called ‘‘ supero-frontal”’ and ‘‘ infero-frontal.” There is no appearance either 
' The nomenclature proposed by Mr. Huxley (Proc. Zool. Soc. 1861, p. 259), founded on that of M. Gra- 
tiolet, is used thronghout, when speaking of the cerebral sulci and gyri of the Quadrumana. 
