DAPHNIAD^. 77 



were considered by Schocffer 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. Miiller describes five pairs in 

 D. penned* i (fiidex], 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 1} 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 antennas, 

 into the interior of the shell of the female, and grasping 

 her feet. 



The male organs of generation have never been ob- 

 served, Midler having mistaken the superior antenna 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 



