130 THE VOYAGE OF H.M.S. CHALLENGER. 



and the Anthropoid Apes, is absent in the non-anthropoid Apes ; and that it is not likely 

 that a character which is only found in the most highly developed brains of the Primates 

 should, when absent in the lower Apes, reappear in the Carnivora in which the frontal 

 lobe is only rudimentary. In connection with this matter it should be stated that the 

 area (8), which Ferrier associates with elevation of the upper lip so as to display the 

 canine teeth, is situated in the Monkey in the lower part of the ascending frontal con- 

 volution and in the Dog at the anterior composite end of the 2nd and 3rd external 

 convolutions ; whilst the area (9), which he associates with the opening of the mouth, 

 movements of the tongue, and not unfrequently barking or growhng, is situated in the 

 Monkey in the lowest part of the ascending frontal convolution, where the inferior 

 frontal convolution springs from it ; and in the Dog in the composite convolution 

 formed by the junction of the lower ends of the anterior limbs of the 3rd and 4th 

 external convolutions. Areas (8) and (9) are placed therefore in the Monkey 

 immediately behind the prsecentral fissure and in the Dog immediately behind the prse- 

 sylvian fissure. 



The results obtained by experiment would seem therefore to harmonize with the 

 conclusion founded upon more purely anatomical data, and I think it probable that the 

 praesylvian and praecentral fissures are homologous. 



A number of years ago I described in the brain both of the Chimpanzee and of Man ' 

 a fissure within the parietal lobe which I named the intraparietal fissure. 2 It is 

 situated in the first instance behind and parallel to the ascending parietal convolution, 

 and then runs almost horizontally backwards to separate the ascending and postero- 

 parietal convolutions from the supramarginal gyrus or convolution of the parietal 

 eminence, and it may be seen in the brain of a sixth month's human fcetus. Pansch 

 subsequently recognised the importance of this fissure and regarded it as the third 

 and most posterior of the three primary fissures on the cranial surface of the brain ; he 

 believed it to be homologous with the anterior part of the middle or second curved 

 fissure of the Dog — the lateral fissure of this Report. 



In the Human brain the intraparietal fissure is separated from the Sylvian fissure by a 

 convolution which, under the name of supramarginal gyrus, or, as I have termed it, the 

 convolution of the parietal eminence, 3 forms a single tortuous tier. In the Dog, again, 

 two tiers lie between the lateral and Sylvian fissures, viz., the suprasylvian and Sylvian 

 convolutions, separated from each other by the suprasylvian fissure. Pansch makes 

 no attempt to explain this difference, and, in the absence of such explanation, diffi- 

 culties at once suggest themselves as to accepting his view of the homology of the intra- 

 parietal fissure and the anterior part of the 2nd curved fissure. But, on the theory 



1 See niyrnernoirs already quoted, pp. 95, 126. 



2 Ecker and some other anatomists have misnamed it the interparietal fissure. 



3 Relations of the Convolutions of the Human Cerebrum to the Outer Surface of the Skull and Head, Journ. of 

 Anat. and Phys., voL viii. p. 142. 



