Brain structure which is caudally attached to the rostral medulla oblongata and extends into the tectal ventricle. The valvula cerebelli consists of a granular and a molecular layer along with aggregations of large Purkinje and eurydendroid cells and is uniquely present in ray-finned fishes. From Neuroanatomy of the Zebrafish Brain. [ https://www.worldcat.org/search?q=bn%3A3764351209 ]