OF THE ORANG UTANG. 7 



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 Lemuridae. Two figures 1 of the brain 

 of the gibbon given by M. Sandifort, which present a relation of 

 the cerebral lobes to the cerebellum, 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 2 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 inde- 

 pendent 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 sub-globular 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 

 sub-equal to the transverse diameter as taken from the one supra- 

 mastoid 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 

 mastoid 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 sinuous brains 

 as above specified, upon the unanimous assent of every one of the 

 plates given by M. Gratiolet in his 'Me'moire sur les Plis Cere- 

 braux,' and upon Tiedemann's figures of the brains of the Simla 

 rhesus, Simla nemestrlna, Simla sabceus, and Cebus capuclnus. If the 

 weight of this latter mass of evidence is not sufficient to make us 



1 Gratiolet, ' Me'moire sur les Plis Cerebraux,' Plancbe iv. fig. I and 2. 



2 'Comptes rendus/ Avril t, i860, p. 803. 



