THE FOREBRAIN AND MIDBRAIN OF THE ALLIGATOR WITH EXPERIMENTAL TRANSECTIONS OF THE BRAIN STEM

Abstract

There has been some previous evidence that in reptilia we have, in addition to a mesial cortical area, which is probably olfactory, the early development of other cortical correlation centers, the beginning of a neopallium. The elder Herrick has, without going into any speculations of functional assignments, suggested the appearance of a visual cortex. Edinger, Meyer,¹ Brill² and others distinguished a mesial, a lateral and an intermediate region of cortex. Crosby,³ demonstrated this division in histologic preparations in the alligator at about the same time that Johnston⁴ showed that stimulation of an area of the cortex in turtles and lizards caused very definite movements of the extremities without, however, identifying the region with one of the histologically determined fields. A recent paper by one of us⁵ reported the results of stimulation of the forebrain of the alligator. In our previous experiments the brain was exposed