456 PROF. A. H. GARROD ON GELADA RUEPPELLI. [May 20, 



In Gelada the right and left central lobes are proportionally 

 larger than in the genera above described. Otherwise it most 

 resembles Cercopithecus, differing from it in that the cystic fissure 

 is shallow, at the same time that the fundus of the gall-bladder does 

 not so nearly approach the inferior border of the right central lobe. 

 It resembles Cercopithecus in that the Spigelian lobe is absent, at the 

 same time that the caudate lobe is long, in both which respects it 

 contrasts strongly with Cynocephalus. The only lobelet is one on 

 the right border of the umbilical fissure, which is Macaque-like. It 

 differs from Macacus in the obliquity of the inferior border of the 

 right central lobe, and in the nearness of the gall-bladder to the 

 umbilical fissure, as well as in the absence of a Spigelian lobe and 

 the large size of the central lobes. 



The brain of Gelada rueppelli is particularly instructive when com- 

 pared with the beautiful series of figures in Gratiolet' s • Memoire 

 sur les Plis Cerebraux de 1' Homme et des Primates.' Its different 

 aspects are represented, natural size, on Plate XXXVIII. Its most 

 marked feature is the relatively small size of the occipital lobe, which 

 is about as large as in the Semnopitheci, smaller than in the Cynoce- 

 phali, and much smaller than in Macacus as well as Cercopithecus. In 

 the two last-named genera this lobe is unconvoluted, or very slightly 

 so. In Gelada there is a simple horizontal sulcus (h, h) a short 

 distance above its lower border, running from the posterior surface 

 some way forward, but not so far as to meet the posterior transverse 

 sulcus (c, c) . In Cynocephalus the occipital lobe is more elaborately 

 convoluted. 



An inferior horizontal occipital sulcus, parallel to that just de- 

 scribed, runs so far forward as to join the major oblique temporo- 

 parietal sulcus (b, b). This is a condition recorded by Gratiolet in 

 ISemnopithecus maurus only, the sulcus generally turning upwards to 

 end independently. 



The major oblique temporo-parietal sulcus (b, b) commences 

 below, near the inferior rounded margin of the temporal lobe, and 

 runs upwards as well as backwards to near the middle line of the brain. 

 It is joined by the prolongation upwards of the Sylvian fissure (a, a), 

 two thirds from its lower end, it being bent slightly forward at the 

 poiut of junction. 



Surrounding the upper end of this last sulcus, but not meeting it, 

 is one whose posterior limb (c, c) forms the anterior boundary of the 

 occipital lobe, the posterior transverse fissure, whilst its anterior 

 limb (y, y) runs forwards, downwards, and outwards, to end inde- 

 pendently as in allied Piimates. "Where these two limbs meet a 

 small sulcus runs inwards to the middle line, becoming conspicuous 

 on the median aspect of the hemisphere. 



The prolongation upwards and backwards of the Sylvian fissure 

 on the outer surface of the brain meets the major oblique temporo- 

 parietal sulcus as above mentioned. Whether or not it should meet 

 it is uncertain in allied species of the same genus according to 

 Gratiolet. It is peculiar, however, in that from a little above and 

 below its middle it sends forward small branches (e. e and n, n). In 



