Chap. XVI.] SOME OTHER MAMMALS. 277 



There cannot therefore be, among animals of the same 

 order, any simple or delinite relation between the degree 

 of the Intelligence of the creature and the numler or 

 disposition of its Cerebral Convolutions — since this struc- 

 tural feature of the Brain seems to be most powerfully 

 regulated by the mere bulk of the creature to which it 

 belongs. But if, when taken alone, the degree of com- 

 plicacy of the convolutions affords no safe guidance in 

 regard to the degree of an animal's Intelligence, when 

 comparing different species of the same order (whose 

 convolution al ' pattern ' is therefore the same), it will be 

 found to fail even more, as a criterion for estimating the 

 relative Intelligence of representatives of different natural 

 orders — especially if these should happen to be orders 

 characterized by a different convolutional 'pattern.' Thus, 

 the brain of the Beaver is almost smooth, while that of 

 the Slieep presents numerous convolutions which both in 

 number and complexity decidedly surpass even those of 

 the Dog. 



The more closely animals are related to one another, 

 however, and the more they are of about the same size, 

 the more should we be entitled to look for some propor- 

 tional relations between the development of their Cerebral 

 Convolutions and their Intelligence. The comparison of 

 convolutional complexity is therefore of principal interest 

 and value when we are concerned with species of the same 

 or closely allied orders, or, even more, when we compare 

 the Brains of individuals of the same species, or of mere 

 varieties, with one another. This kind of interest, there- 

 fore, culminates in the comparison of the degrees of con- 

 volutional complexity to be met with among the different 

 races of Man. 



In taking account of the mere size of the Brain in 

 di.Terent animals, as well as of its degree of convolutional 



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