Izerbacea and arctic species generally, to 1 oo ft., and occurring most abundantly in cold or temperate climates in both hemispheres, and generally in moist situations; a few species occur in the tropical and sub-tropical portions of the three great continents.
The largest genus of the order, the sedges, is widely distributed in the temperate, alpine and arctic regions of both hemispheres, and is represented by 60 species in Britain.
There is very little grey matter in the cortex of the hemispheres, the surface of which is devoid of convolutions, mostly quite smooth; in others, for instance pigeons, fowls and birds of prey, a very slight furrow might be compared with the Sylvian fissure.
The right and left lobes themselves are rent asunder (so to speak), so that they are freely visible from above, filling the corners formed by the hemispheres and the cerebellum.
Several futile attempts have been made to draw conclusions as to the intelligence of various birds.