1) Cerebral cortex 2) Cerebral mantle 3) Cortex 4) Paleocortex 5) Pallium 1) Paleocortex 
In anatomy of animals, the archipallium is the oldest region of the brain`s pallium. The archipallium is often considered contiguous with the olfactory cortex, but the extent of the archipallium varies among species. In older species, such as fish, the archipallium makes up most of the cerebrum. Amphibians develop an archipallium and paleopallium....
(from the article `nervous system`) ...but in birds and primates in which sense of smell is less important the lobes are reduced in extent. In amphibians the hemispheres consist of ...
Synonym: archicortex. ... Origin: archi-+ L. Pallium ... (05 Mar 2000) ... 
(ahr″kĭ-pal´e-әm) archicortex.
Type: Term Pronunciation: ar′ki-pal′ē-ŭm Synonyms: archicortex
[n] - the olfactory cortex of the cerebrum
paleocortex noun the olfactory cortex of the cerebrum
Greek archi = first, and pallium = cloak, hence the cortex which developed first in vertebrates. Often synonymous with hippocampal formation.