Fig. 8. Terminal relations of optic tract in mammalian brain. Ch, chiasm; Op Tr, optic tract; Gl, lateral geniculate body; Gm, medial geniculate body; C, superior colliculus; R, red nucleus; SN, substantia nigra; a, anterior accessory optic tract; b, posterior accessory optic tract; c, fibers to large cell nucleus of optic tract. (LeGros Clark WE: The structure and connections of the thalamus. Brain 55:442, 1932)