200 PHYSIOLOGICAL SERIES. 



from the interhemispheral cleft. A comparison with the 

 brains of Orycte)'opus,the Anteaters, and Carnivore- would 

 lead us to call this the lateral or the conjoint corono-la trial 

 sulcus. Yet it is very unusual to find the lateral sulcus 

 present, and the more precocious and fundamentally stable 

 suprasylvian sulcus absent. If, for instance, we compare 

 this brain with that of Galeopithecus and many of the 

 smaller Ungulates, the possibility of it being the supra - 

 sylvian presents itself. 



Taking all its features into consideration, one is inclined 

 to regard it as tho analogue of the lateral sulcus of such 

 a form as Tamanduas. It is also clear that the anterior 

 extremity of such a sulcus takes the place of the prorean 

 sulcus found in the Marsupialia and Carnivora. 



Two notch-like indentations in the upper lip of the 

 rhinal fissure may represent the Carnivore pseudosylvian 

 sulcus and the orbital sulcus. 



Other sulci have been described in the Agouti ; in this 

 specimen shallow depressions occupy the positions of all 

 these sulci. 0. C. 13230. 



Beddard, Proc. Zool. Soc. 1892, p. 602. 



D 253. The brain of the Paca (Agouti paca). 



This brain agrees with that of the Agouti in presenting 

 notch-like representatives of the orbital and pseudosylvian 

 sulci in the upper lip of the rhinal fissure. 



The longitudinal (" lateral ") sulcus of the Agouti is here 

 broken up into two fragments anterior and posterior 

 paramedian sulci respectively, and between them is a short 

 oblique sulcus (which I shall call " ambiguus "), such as 

 the Porcupine exhibits. 0. C. 1323 o b. 



Beddard, Proc. Zool. Soc. 1892, p. 604. 



Family CAVIIDJE. 



D. 264. The brain of a Capybara (Hydrochcerus capybara), in 

 which the left cerebral hemisphere has been separated from 

 the n-st of the I. rain (figures 71, 72, and 73). 



Thi.- lirain is much the largest found in the Uoilentia ; 



