Their mouth is of moderate width, oblique, and armed with small but firmly set teeth.
The typical Siamese is of medium height, well formed, with olive complexion, darker than the Chinese, but fairer than the Malays, eyes well shaped though slightly inclined to the oblique, nose broad and flat, lips prominent, the face wide across the cheek-bones and the chin short.
The greatness of the thickness, as it has been measured, is also due in part to the oblique position in which the beds of sediment were originally deposited.
Note thick walls and oblique slit-like pits with opposite inclination on the two sides of the cell seen in surface view.
But even with homogeneous light it would be unreasonable to expect an oblique direction of perfect polarization.