Dictionary.net

• A thin layer of white matter extending between the superior peduncles of the cerebellum.

1920 - A dictionary of scientific terms.
By Henderson, I. F.; Henderson, W. D.

• A triangular lamina of white nerve substance which bridges over the interspace between the superior cerebellar peduncles, forming a portion of the roof of the fourth ventricle. [Lat.]

1916 - Appleton's medical dictionary
By Smith Ely Jelliffe