Which of the following statements is not true? （ ）
选项：

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.