or THE CEEEBEHM OE THE QHADEHMANA. 
197 
those of the Carnivora. The corpora albicantia are represented by a single mass, which 
however is cleft posteriorly, indicating its separation into two portions. The corpora 
geniculata form distinct white nodules on the sides of the crura, but not visible until the 
edge of the temporal lobe is slightly lifted up. The pons is but little elevated. The 
medulla oblongata is very wide, and the tracts called corpora trapezoidea clearly marked 
out. The corpora quadrigemina resemble those of other Quadrumana, the anterior 
being larger and of more rounded form than the others. The cerebellum shows a 
marked inferiority to that of the true Monkeys. The median vermis, especially the 
inferior portion, is very large. The lateral vermis (flocculus) is also greatly developed, 
and forms the principal part of the lateral mass of the cerebellum. The body of the 
lobe is, however, not so much reduced as in the Carnivora. 
To return to the cerebral hemispheres. A section was made through the right 
posterior lobe at the point B (Plate III. fig. 14). The calcarine sulcus is now seen to 
extend to about the middle of the section, but to be of the simplest form. The cortical 
layer which it carries with it (hippocampus minor) is bordered by a thin stratum of 
white substance, which is separated from the contiguous medullary cerebral matter, as in 
the other Quadrumana, by a fine crescentic line, indicating the presence of a posterior 
cornu of the lateral ventricle. In a horizontal section of the left hemisphere this 
cornu appeared as a mere fissure, with walls in close apposition, but traceable nearly to 
the termination of the hemisphere. In this view, the most marked difference between 
the parts displayed, and those of the ordinary Quadrumana, consisted in the compara- 
tive shortness of the posterior lobe, this being, as compared with the antero-median 
portion, only as 35 to 100. 
None of the authors who have written upon the brains of the Lemuridee, whose works 
I have been able to consult, describe a hippocampus minor. Veolik expressly states 
that it is absent in Stenojps (“ L eminence digitale, I’eminence collaterale de Meckel 
manquent,” op. dt. p. 79), and Bukmeister alone mentions a posterior cornu to the 
ventricle in Tardus, the only observation upon it being, that it is “very long.” There 
can be no doubt, however, of the strict homology of the calcarine fissure, and its 
surrounding grey matter (hippocampus minor), in the Lemur, to that of the parts so 
described in Man and all the intermediate forms ; and that in this low and almost aber- 
rant member of the order, although of reduced length, corresponding with that of the 
hemisphere, it extends more deeply into, and bears a greater ratio to the surrounding 
mass of the lobe than it does either in Man or in the anthropoid Quadrumana. 
The presence of the same parts is shown even more distinctly in the brain of a Galago 
{Otolicnus) preserved in the Museum of the Middlesex Hospital. The animal to which 
it belonged died in the Zoological Society’s Gardens in 1852 *. While alive it was 
referred to 0. Oarnettii (Ogilbt), but its dimensions did not agree with those of the type 
specimen of that species in the British Museum ; its generic determination is, however, 
sufficient for the present purpose. For reasons given in the case of the Orang, I do not 
* See Proc. Zool. Soc., March 23, 1862, p. 73. 
