MORPHOLOGY OF THE BKAIX IX THE :^IA^r.MALlA. 



401 



found in tlic Viverrida']. There are neither postsylviaii nor postUiteral sulci ; but 

 the suprasylvian and lateral sulci extend almost to the posterior extremity of the 

 hemisphere *. 



Fig. 59a. 



Fig. 59 6. 

 sL 



sps. 



Figs. 50 n & h. — CiiiwJiiiirnoiloii Cai/hi.ri. (it) dorsal .■iml (/>] lalorul aspects of a natural cast o 



jf part of 



tlic cranial cavil v. Nat. sii:e. 



If we turn to the examination of tlie lateral surface of the hemisphere in tlie Ungulata 

 (leaving out of account certain sulci, such as the intercalary, which often leaves the 

 mesial and extends on to the dorsal surface f ) we shall find in Procai-ia, which is perhaps 

 the most generalized member of the Order, an arrangement of sulci whicli is obviouslv 

 identical with that of the hypothetical primitive Carnivore. 



The suprasylvian and coronal sulci closely resemble those of Viverra, and especiallv 

 the Eocene Carnivores, both in position and extent. The lateral sulcus is usually less 

 well-developed, and is always separated from the coronal sulcus ; but there cannot be 

 the slightest doubt as to its identity with the similarly-named sulcus in the Carnivora. 

 In some cases the lateral sulcus is absent. 



The i)se\ulosylvian sulcus is almost always absent, but in one brain (of eight examined) 

 I found a furrow resembling tliat sometimes seen in J'ieeri'u. Tliat this sulcus was no 

 mere vascular furrow was shown by the presence of a vertical postsylvian sulcus J in that 

 brain and not in others. Another instance of a similar phenomenon is shown in Turners 

 figure of the brain of ILjrax \_Procaijia'] (Journ. Anat. and Physiology, vol. xxv. 1900). 



A small typical orbital sulcus is almost invariably present, although it has been 

 overlooked by both Krueg and Turner. There is no diagonal sulcus. 



If the developmental history of the cerebral hemispheres be studied in a series 

 of Ungulates §, it will be found that the earliest sulci to make their appearance on the 

 outer surface of the hemisphere are those which from their relations and behavioiu" are 



* There is not much resemblance between this cast and that tigured b)- Filhol. There is no doubt, however that. 

 even if this is not what it is represented to be, it is certainly an Eocene Carnivore. 



t As a similar phenomenon is presented in the brains of certain Carnivores, such as lldictis, and, less decidedly 

 in Mcles, there can he no doubt as to the homologies. 



+ This showed that there was a furrow of sufficient depth to lend a bias to the neighbouring cortex. 



§ Such investigations have been made by Krueg (Zeitsch. f. wissensch. Zoologie, 13d. ixxi.), and more recently by 

 Paul Martin (" Zur Entwickelung der Gehirnfurchen bei Katze und Rind," Arch, fiir wissensch. u. prakt. Thierheilk., 

 ]Jd. xxi. Heft i., 189.5), and I have studied this problem in embryos of Ovis. Bos, Capra, Sus, and C'amelus. 



Bradley has published a few data concerning the Horse's brain in the Journ. Anat. and Phys. vol. xxxiii. pp. 215 

 & 5«7. 



58* 



