204 OEIGINAL AKTICLES. 



The greater width of the semilunar segment exposed on the left side 

 was, no doubt, owing to the gravitation of the cerebral lobes, but the 

 greatest width of this segment was only three lines. The relations thus de- 

 scribed are well shown in PL iii., fig. 3. The view of the base of the brain, 

 as given in fig. 2, will enable us to complete our observations as to the 

 relations of the cerebellum to the posterior lobes of the cerebrum. On 

 looking at that figure, it will be seen that no cerebral surface comes into 

 view on the outside of the lateral boundaries of the cerebellum. In a 

 view of the base of the human brain, some cerebral substance is invariably 

 seen in this situation; but the same is the case with a second orang's brain, 

 with a chimpanzee's brain, and with the brains of several Cercopitheci } 

 and an Inuns, in the Series belonging to the Christ Church Museum. The 

 cerebellum does not project so far laterally as to cover the cerebral lobes 

 in a basal view of any brain in Tiedemann's Icones which is above the 

 rank of the Lemuridce. Two figures'" of the brain of the Gibbon given by 

 M. Sandifort, which present a relation of the cerebral lobes to the cerebel- 

 lum, much resembling that which I have described in the brain of the first 

 of the two orangs in our museum, M. Gratiolet regards with suspicion, 

 whilst he himself records the existence! of a similar relation of the two 

 parts of the encephalon in the gorilla. M. Gratiolet gives the figure of the 

 brain of the chimpanzee as drawn by Tyson, only to express a strong 

 opinion as to its worthlessness ; and as he condemns it, as well as the two 

 figures of M. Sandifort, on grounds quite independent of the view they 

 give of the cerebellum and its relations, we may, perhaps, be justified 

 in disregarding any evidence which might be based upon these three 

 figures, and in considering the condition and relation of the parts in the 

 subject of this paper as an individual, rather than a specific, peculiarity. 

 The roof-like exterior of the skull of the gorilla would prepare us for 

 meeting with quite another relation of cerebellum and cerebrum than that 

 which we find in the subglobular skulls of the smaller anthropoid apes. 

 For, though the transverse diameter in these latter skulls taken from one 

 parietal protuberance, or rather from one spot homologous with such 

 protuberance to the other, is only subequal to the transverse diameter, 

 as taken from one supramastoid region to the other, it is yet never 

 markedly inferior, as is the case with the gorilla, to a degree for which 

 no development of mastoidal air-cells can account. 



The evidence, then, for the lateral predominance of the cerebellar 

 lobes rests upon the single instance, the subject of this paper, and upon 

 the three representations which M. Gratiolet sees, upon other grounds, 

 good cause for condemning. Against it, is to be set the evidence based 

 upon the examination of several other simious brains as above specified, 

 upon the unanimous assent of every one of the plates given by M. 

 Gratiolet in his Memoire sur des Plis Cerebraux, and upon Tiedemann's 



* Gratiolet, Memoire sur les Plis Cerebraux. Planche iv., fig. 1 and 2. 

 | Comptes Rendus, Avril, 1860, p. 803. 



