10 MB. ST. GEOEGE MIVAET ON THE 



hippocampal into the sagittal gyrus behind the place of the 

 crucial sulcus. Secondly, they difter from the Dogs in the non- 

 bifurcation posteriorly of the parietal gyrus. Thirdly, they all 

 agree together with both the Canidae and Eelidee in not having 

 any complication of the crucial sulcus. by the extension of sub- 

 ordinate sulci forwards and inwards in front of its anterior 

 margin. 



The non-canine and non-feline species here considered — all o£ 

 which belong to the non-feline portion of the suborder ^lu- 

 roidea — divide themselves, as regards their cerebral structure, 

 into two marked groups. To one of these belong the genera 

 Viverra, Genetta, Nandinia, Paradoxurus, Arctictis, Cynogale, 

 and Eupleres^', which all (so far as I have been able to observe) 

 differ from other Carnivora by the abortion, or quite rudimentary 

 condition, of the crucial sulcus. Contrasted with these are 

 the -3^^1uroid genera Herpestes, Galidia, CrossarcTius, Svricata, 

 Sycena, Grocuta, Proteles, and Cryptoprocta, all of which ag-ree 

 in having a well- developed crucial sulcus and a Sylvian gyrus, 

 the hinder limb of which is twice or more (except sometimes in 

 Serpestes) the breadth of its anterior limb, and bears a vertical 

 groove. 



We come now to the series of forms which constitute the 

 Arctoid group of the Carnivora. 



Frocyon. — The brain of the Eaccoon t, like that of all the 

 forms which have hereinafter to be noticed, has three circum- 

 Sylvian gyri, whereof the parietal gyrus does not bifurcate pos- 

 teriorly, thus differing from the Canidse. The Sylvian gyrus has its 

 anterior limb much smaller than its posterior limb. The parietal 

 gyrus is large, expanding anteriorly, becoming considerably con- 

 torted, and sometimes communicating, by a bridge of convolution 

 with the sagittal gyrus. The sagittal gyrus is very large, and 

 becomes complicated anteriorly. This I find to be especially the 



* Thus the cerebral structure justifies the affinities and classification of the 

 ^luroids which I indicated in my paper on that group (in the Proc. Zool. Soc. 

 1882, p. 135), except as regards Etipleres, which I associated rather with the 

 Ichneumons than with the Civets. It is interesting to note the evidence 

 afforded by the brain of the affinity between the Hyaenas and the Ichneumons. 

 Professor Flower had already remarked (P. Z. S. 1869, p. 482, note §) the 

 greater resemblance of the brain of the Suricate to that of the HyEenas than to 

 that of the Civets. 



t See P. Gervais, /. c. p. 141, pi. viii. fig. 1 ; Krueg, I. c. pi. xxxvii. p. 633 ; 

 and Burt Wilder, I. c. pi. ii. fig 11. 



