[John Valentine]

The Equatorial Axis is the intersection of a sphere’s surface with the plane perpendicular to the sphere’s axis of rotation and midway between the poles.

You are describing a circle (intersection of the surface of a sphere with a plane), whereas the pictorial representation is not a circle, but a straight line intersecting the surface of the planet at two points: 9˚ south latitude, 91˚ east longitude and 9˚ north latitude, 89˚ west longitude. Since an "axis" is generally a line, and your explanation is at odds with the diagram provided by the authors, I suggest your post fails to explain the significance of this odd "axis".

[moose07]

This may help:

90 degrees to axis of rotation.