shape of, [253], [371];

position of, [254-257], [263];

connected with canals, [256], [257], [262], [371];

disprove diplopic theory, [258];

objectivity of, [263];

in dark regions, [163], [244], [263], [264];

kinematic character of, [330-333];

latitudinal progress of change in oases, [331];

evolution of, [331], [332];

intrinsic change in, [337], [338];