THE BKAiX IX THE EDENTATA. 313 



Writing thirty years after Leuret's original memoir, Pouehet says * tliat the Ant-eaters 

 form with Oryeteropus a separate group, in which we find an agreement in the arrange- 

 ment of the convohitions and in the general form of the brain. The same writer says 

 (p. 1(3), in reference to a late foetus of Oryeteropus : — " Quant aux circonvolntions, leur 

 analogic est complete avec celles du Tamandua." He proceeds to state that in tlie adult 

 the resemblance to Ilyrmecopliaya becomes more marked. In giving details to support 

 the latter statement, Pouehet gives a free rein to his imagination. Probably the 

 culminating instance of this is his statement that the fissure of Sylvius is well 

 marked (p. 17). There is not the faintest trace even of a, fossa Sylcil. 



Gervais also insists in equally decided terms upon the close resemblance between the 

 hrain, and especially the cerebral cortex, in Myrmecophaga and Oryeteropus t. He 

 concludes his remarks upon this suhject with the following words :—" Je lui [I'Orycterope] 

 trouveune analogic incontestable aveccelui du grand Fourmilier, c'est a dire duTamanoir. 

 L'un et I'autre ont daus leur forme quelque chose du cerveau des Carnivores, mais avec 

 moins de circonvolutions, et le type en ]-este distinct a certains egards." And For])es 

 adds his testimony to this fancied resemblance, wdiich Pouehet and Gervais had pre- 

 viously described, in the following tei-ms : — ''Oryeteropus in its cerebral characters seems 

 to approach Myrmecophaya more nearly than any other form, the sulci and gyri of the 

 brains of the tw^o forms, as well as tlieir conformation, being very similar " %. 



In two animals which follow similar modes of life and whose dimensions are not 

 widely different, it would be strange if there were not some points of resemblance, but 

 there is not so much justification for pointing resemblances in the pallium of Oryeteropus 

 and of Myrmecophaya as there would be in a comparisan of Ocls with Canis. It is 

 perhaps only just to the authors of the remarkable statements quoted al)ove to 

 mentioned that there is no evidence to show that any of them ever saw the brain of an 

 adult Oryeteropus. 



In spite of a somewhat illusory resemblance in general shape, which iiaturally obtrudes 

 itself in the examination of cranial casts, the configuration of the actual brain of 

 Myrmecophaga presents a decided contrast to that of Oryeteropus. To begin with, the 

 shape of the pallium is very different in the two forms. For in Oryeteropus the ventral 

 boundary of the pallium, Avhich of course is formed by the rhinal fissure, is horizontal ; 

 and hence there is no caudal downgrowth of pallium such as we find in the brain of the 

 Ant-eater. There is no trace of a fossa Sylvii in Oryeteropus, for the pallial area immedi- 

 ately above the mid-region of the rhinal fissure is quite smooth. 



In my specimen of Oryeteropus a sulcus, the arrangement of which is analogous to 

 that of the supraorbital or presylc'uni sulcus of the Dog and to the sulcus 3 in Myrme- 

 cophaga, springs from the mid-point of the anterior rhinal fissure, and extends obliquely 

 forward and upward to wnthin a distance of about 5 mm. from the interhemispheral 

 cleft. In the two brains of Oryeteropus in the College of Surgeons, this sulcus springs 

 from the cephalic extension of the posterior rliiual fissure, which is independent of the 

 anterior rhinal fissure. 



* G. Pouc-befr, 0^). clt. torn. vi. p. 15. t P. Gervais, op. cti. pp. 47 & 48. 



X W. A. Forbes, op. cit. p. 295. 



47* 



