ABSTRACT
Cortical dominance reaches its highest expression in man. The varying degrees to which it demonstrated itself in the monkeys and apes of J. F. Fulton and A. D. Keller investigations may be regarded as stages in one particular cortical evolution. In Fulton and Keller’s own words, “as one ascends the primate scale the state of monoplegia observed after a lesion of the motor cortex comes to simulate more and more the condition of reflex depression seen after transection or semisection of the spinal cord.” Even where differences in the dynamic construction of the cortex of the brains of different sub-human members of the catarrhine division of the Primates are revealed, they appear, however, to have little value in the natural economy of monkeys and apes in general. Sxual division of labour in the collection of food is not known to occur amongst sub-human Primates.
