A PHYSIOLOGICAL AND HISTOLOGICAL STUDY OF THE FRONTAL CORTEX OF THE SEAL (PHOCA VITULINA)

¹ From the Department of Anatomy, Harvard Medical School

The exposed cortex of the frontal lobes of the left hemispheres of six young seals (Phoca vitulina) under dial anæsthesia was stimulated electrically. Movements of the tail, both hind-flippers and the contralateral fore-flipper, neck and face were evoked. The cortical localization is charted in Fig. 2.

Histological examination (thionine stain) of three frontal lobes revealed a well-developed cortex divisible into cytoarchitectural areas structurally similar to those in other carnivores, but differing in their extent and their relation to the sulci (Fig. 2).

On the basis of a comparison of the seal with the terrestrial carnivores it is concluded that the degree of differentiation of the cortical representation is to be correlated with function and not with form.