The Efferent Fibres of the Hippocampus in the Monkey

Speculations upon the functions of the hippo-campus have been numerous in the last few years and have led to some important experimental studies. In the critical review by Brodal (1947) the obscurity surrounding the afferent connexions of the hippocampal complex was stressed. Since the publication of this paper, the hippocampal afferents from the cingulate cortex have been examined experimentally in the rabbit (Adey, 1951) and in the monkey (Adey and Meyer, 1952) by Glees' silver method, and Pribram, Lennox, and Dunsmore (1950) have presented electro-neuronographic experi-ments on the connexions of the entorhinal and prepiriform areas in the macaque. The efferent projection of the hippocampus has been the subject of some recent experimental studies, notably those of Sprague and Meyer (1950) on the rabbit, employing the Glees method, and of Allen (1944, 1948) upon the dog, using both the Marchi technique and the examination of early retrograde changes. These experimental investi-gations were made on lower mammals, and earlier