330 



PROF. G. ELLIOT SMITH ON THE 



olfactory tract," wliich Retzius calls "gyrus intermediiis " [op. cU. »upra). To the 

 mesial side of this tuhercle there is a narrow transverse cleft — the locus perforatus — 

 between the tuberculum olfactorium and the large optic chiasma. 



To rightly ap])reciate the nature of the exposed part of the fascia dentata (fig. 4), the 

 mesial surface of the hemisphere must be exposed by cutting through the cerebral 

 commissui-es and lamina terminalis and severing the attachment of the optic thtnlamiis 

 to the coi"pus sti'iatum (fig. 5). 



Fig. 5. 



Fig. Ga. 



ss. d. 



Fig. 5. — Lemur faJrus. The mesial aspect of the i-ight cerebral a.speet. x 2, 



Fig. 6. — Lemur fulvua. Left lateral aspect of the brain, x 2. 



Fig. 6 a.— Part of the same after removal of part of the caudal opercular lip of the sulcus pseudosylvius. x 2. 



Fig. 6 h. — Part of the aame shaded iu order to roughly indicate the area of distribution of the claustrum (c/.). x 2. 



Fig. 7. — Lemur macaco. The left lateral aspect of the brain. Natural size. 



The hippocampal formation is thus partly exposed as a series of bands ascending 



