These shells are identical with those of the mollusca of Lake Ngami and the Zouga.

There are three varieties, spiral, univalve, and bivalve.
In every salt-pan in the country there is a spring of water on one side.
I can remember no exception to this rule.

The water of these springs is brackish, and contains the nitrate of soda.

In one instance there are two springs, and one more saltish than the other.

If this supply came from beds of rock salt the water would not be drinkable, as it generally is, and in some instances, where the salt contained in the pan in which these springs appear has been removed by human agency, no fresh deposit occurs.