Figure 4B.15. This shows the cylindrical construction of a tube. At the center is a dot indicating the end view of the heater. Surrounding the heater is the insulator and surrounding that is the cathode. The target surrounds the whole thing. Between the cathode and target is the shadow control grid which subtends an angle of 90 degrees centered at the bottom of the circle. Just outside of the target control grid and at the bottom center, just inside the target is a dot representing the end view of the shadow rod.
End of verbal description.