no MR. FLOWER ON THE BRAIN OF THE JAVAN LORIS. 



Apes : the cerebrum is so short as to leave almost the whole of the cerebellum 

 uncovered, and the Sylvian fissure is almost obliterated. On these grounds alone we 

 might be induced to place these orders far away from each other, in a system of classi- 

 fication founded mainly on cerebral organization, if the fact of the persistence of the 

 primatial type of convolution upon a degraded configuration of brain in the Lemurs did 

 not warn us that it is possible that the Cheiroptera, and perhaps the Insectivora also, 

 may form a group presenting a still lower degree of development (characterized by still 

 shorter hemispheres) of the same high type, and that therefore, in the absence of any 

 knowledge of what the surface-markings of the hemispheres of the Cheiroptera would 

 be if developed, there scarcely seems sufficient justification for removing them, on the 

 score of their cerebral organization alone, from the position assigned to them on other 

 grounds by Linngeus, Cuvier, and a large majority of systematic zoologists. It may 

 be, perhaps, that we shall find in the simpler brains of this lower group a common 

 form by means of which the more completely developed and specialized cerebral 

 organs of the Carnivora and the Quadrumana are united, and through which, instead 

 of through any direct link, their affinities are to be read. At all events, it cannot be 

 doubted that more searching comparisons of the form and the convolutions of the 

 brains of different groups of Mammalia, conducted on such a system as that so suc- 

 cessfully pursued in one group by M. Gratiolet, will throw much light upon the mutual 

 relation of different members of the class, and I trust that these few observations upon 

 a very interesting form may be accepted by the Society as a small contribution towards 

 this desirable end. 



Note. — May 1862. The recent examination of the brain of a specimen belonging to 

 the genus Pithecia (Proceedings of the Zoological Society, Dec. 9, 1862) has led to a 

 different determination of the sulci of the posterior part of the inner face of the hemi- 

 sphere to that given above and in the author's paper " On the Posterior Lobes of the 

 Quadrumana" (Phil. Trans. 1852). The sulcus marked k, in figs. 4, 7, & 10 {Stenops, 

 Lemur, and Nyctipithecus), which was supposed to represent the occipito-parietal of the 

 higher Quadrumana, is more probably the upper branch of the posteriorly bifurcating 

 calcarine, because (in Nyctipithecus , without doubt) it is homologous to a small sulcus 

 wliich in Pithecia coexists with a true occipito-pai'ietal descending from the upper 

 margin of the internal face of the hemisphere and, as in all except the highest 

 Quadrumana, not extending so low as to join the calcarine {loc. cit. fig. 4). All trace 

 of this sulcus is absent in the smaller Platyrhine Monkeys and Lemurs. 



