DAPRNIADiE. 
77 
were considered by Schoeffer as pockets filled with a 
liquid destined for the reproduction of the shell at each 
moulting. This opinion, however, has never been verified 
by any succeeding observer. 
Till Jurine and Straus described these insects, the 
number even of the pairs of feet seemed undetermined. 
Joblot believes there are three pairs. Schoeffer says there 
are one or two pairs more. Muller describes jive pairs in 
D. pennata {pul ex), but four only in his longispina. All 
the species of true Daphnia, however, have five pairs. 
In the male, the first pair of feet (t. XII, f. 1 b) differs 
considerably from the corresponding pair in the female. 
It is more slender in form, and has a strong claw or hook 
attached to the extremity of the second joint, while the 
seta which springs from the third joint is very long, nearly 
the length of the body, and floats outside the shell. 
Jurine describes this pair of feet very particularly, and 
shows the use of them to be the same as the hinge-joint 
antennae in the male Cyclops, viz., for seizing and retain- 
ing hold of the female during the act of copulation, the 
male introducing them along with the superior antennae, 
into the interior of the shell of the female, and grasping 
her feet. 
The male organs of generation have • never been ob- 
served, Muller having mistaken the superior antennae for 
them ; neither have the female organs been seen, with 
the exception of the ovaries. That they reside in the 
lower portion of the body appears most probable, from the 
description to be afterwards given of the method of 
copulation, as observed by Jurine. 
Straus thinks they have no external organs at all, but 
that the male simply injects the semen under the valves 
of the female, from which it introduces itself into the 
ovaries. 
The ovaries are placed along the sides of the abdomen, 
as in Cyclops, and show their situation by the matter of 
the eggs, in the shape of small, round, pellucid globules. 
These make their appearance in the young insect after the 
