title: Quantitative composition and histological features of the brain in two South American edentates.
abstract: The volumes of twelve brain components relative to body weights in the armadillo and the tree-sloth have been estimated. The progression of each component with respect to a basal reference type is indicated. The armadillo shows the brain organization of a little evolved mammal with developed olfactory structures and a large pyriform lobe in particular. The sloth possesses a more advanced type of brain with an unexpectedly voluminous neocortex. Some behavioural features probably correlated to the size of brain structures in those Edentates are mentioned and the need for a reconsideration of the concept of primitiveness is stressed.
mesh_terms: D000818:Animals; D001135:Armadillos; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology*; D002531:Cerebellum / Q000033:anatomy & histology; D003342:Corpus Striatum / Q000033:anatomy & histology; D005260:Female; D008032:Limbic System / Q000033:anatomy & histology; D008297:Male; D009830:Olfactory Bulb / Q000033:anatomy & histology; D009929:Organ Size; D012896:Sloths; D013045:Species Specificity