352 DK. G. ELLIOT SMITH ON 



other mammals seems to be much more likely than with the Sylvian fissure, as Weber 

 suggests. 



The arrangement of the sulci in this brain presents a peculiar resemblance, in respect 

 to ditTerent points, to the brain of the Armadillos and Sloths. On the one hand, the 

 general plan, the arcuate suprasylvian sulcus, the sagittal sulcus, and the supraorbital 

 sulcus considered together, strongly recall the brain of the Sloth. And yet we must at 

 the same time admit that these features arc the common inheritance of widely different 

 mammalian families. On the other liand, the condition of the rhinal fissure and its 

 relation to the supraorbital sulcus shed an interesting light upon the brain of the 

 Armadillo. More especially is this the case in the foetal Manis {vide Poiachet, oj). cit. 

 pi. V. fig. 9), in which the combined posterior rhinal fissure and sulcus j3 form an exact 

 facsimile of the arrangement of these sulci in Dasypus. Then, again, the relation of the 

 suprasylvian sulcus (S) to the sulcus /3 in Manis is identical with that of the sulcu.s which 

 we have called S to the sulcus /3 in Dasijpiis. 



In a brief note Huntington sums up * the features of the brain in the Edentata 

 {Mi/rniecophaga, Tamaudim, Arctoplthecus, Dasypus, Tatnsia, and Ilanis) in the following 

 terms: — "In the brain (hemispheres) the uniform presence of a more or less modified 

 longitudinal sagittal sulcus parallel to the great longitudinal fissure, the tendency to the 

 formation of a transverse frontal sulcus, and the absence of a distinct Sylvian fissure, are 

 to be noted as Edentate characters." 



Taken as it stands, this statement is very misleading. In the first place, " the presence 

 of a modified lon""itudiual sa<?ittal sulcus " and " the tendencv to the formation of a 

 transverse frontal sulcus " are no more entitled to be called " Edentate characters " than 

 they are to the designations " Carnivore " ov " Ungulate." Instead of being the special 

 and exclusive characteristic of the Edentata, these sulci are the common property of the 

 whole Mammalia, excluding probably the Mouotremata only. 



This writer also refers to the absence of the Sylvian fissure as an " Edentate character." 

 In the strict application of the term it may be correct to say that the Edentata possess 

 no Sylvian fissure. But to baldly make this statement with no word of exj)lanation 

 cannot fail to give rise to serious misapprehension. Even admitting, for the sake of 

 argument, that the sulcus /// of Bradypus is not as much entitled to the name " Sylvian 

 fissure " as the topographically analogous depression in Genetta, it seems to me to be 

 distinctly misleading to say of Myrmecophaga that it possesses " no distinct Sylvian 

 fissure." Tliis may be literally true enough, but some cvplanation is surely necessary to 

 indicate that although the Great Ant-eater's brain possesses " no distinct Sylvian fissure," 

 yet, at the same time, it differs only in degree from the brain of the Dog, in which a 

 typical Sylvian fissure exists. 



The fuller discussion of the data relating to the pallium will be left for consideration 

 in the concluding remarks. At present we may pass to the consideration of the other 

 parts of the brain. 



* G. S. Huntington, op. cit., Trans. New York Acad, of Sciences, Jan. 13, lb'J6, p. 98. 



