In the book "Yoga and vitality", by James Hewitt, this position is also depicted, on page 21, with the further explanation:

The Egyptian Seat

Even easier than the Easy Posture (Lotus- Seat) is the Egyptian (Chair-) Seat posture, but this should only be used if the Easy Posture appears to be to uncomfortable. Sit down on a chair with a straight back-rest, head and spine should be vertical, the feet and knees against each other, the palm of the right hand  flat on the right thigh, and the palm of the left hand  flat on the left thigh. Breathe freely.