Which of the following statements is not true? （ ）

A、The spinal cord consists of both gray and white matter.
B、A cross section of the spinal cord shows an H-shaped internal mass of white matter surrounded by gray matter.
C、The gray matter is made up of two symmetric portions joined across the midline by a transverse connection of gray matter, the gray commissure."
D、The anterior horn is the enlarged protrusion in the front of the gray matter of each side.
E、The ventral horn contains the cells of origin of the fibers of the anterior roots.