On some West-Australian Entomostraca, 23 
at times getting hold of them for copulation. The ephippia 
were soon formed, and successively dropped to the bottom, 
where they were subsequently easily detected, on account 
of the brick-red egg contained in each of them. The indi- 
viduals now gradually diminished in number, and at last 
wholly disappeared, no specimens reappearing later in the 
season. It would therefore seem, that this form, unlike 
what is the case with the 2 Sydney species previously 
described by the present author, is «monocyclar» in character. 
In habits, this form agrees with the other species, and 
moves in a similar jerky manner, though it is on the whole 
less active, especially in the later generations. 
