midbrain morphology trait Trait.ontology mesencephalon morphology trait Any measurable or observable characteristic related to the shape, structure, color, or pattern of the middle division of the three primary divisions of the developing chordate brain or the corresponding part of the adult brain (in vertebrates, includes a ventral part containing the cerebral peduncles and a dorsal tectum containing the corpora quadrigemina and that surrounds the aqueduct of Sylvius connecting the third and fourth ventricles). VT:0000897 brain morphology trait