DAPHNIA PULEX MULLER 121 



situated right and left of the midgut and extending from the 

 heart region to the posterior bend of the body. The oviducts 

 are short and open separately on the dorsal surface of the trunk 

 into the brood-pouch. The latter is a large space under the shell 

 above the trunk and behind the heart. The partheno genetic 

 eggs develop in this brood-pouch until the young daphniae are 

 able to swim out of the pouch. The so-called winter eggs, i. e., 

 fertilized eggs, are at first enveloped by a special sac called 

 ephippium in the brood-pouch, and the entire ephippium is then 

 deposited into the water. On sinking to the bottom of the pool 

 the ephippium remains there until next spring, when the eggs 

 develop into females. 



Instructions 



1. Place a Daphnia in a watch glass with a few drops of water. 

 Add a drop of io9c ether and examine the animal under low 

 power (50 diameters). Make a full page drawing showing the 

 right side view, but omit from the drawing the left second an- 

 tenna. Label right second antenna, compound eye, ocellus, 

 first antenna, carapace, heart, furca, abdominal tactile bristles, 

 intestine, hepatic cceca, five thoracic limbs, shell gland, muscles 

 of second antenna, brood-pouch with embryos, ovary, if devel- 

 oped. 



2. Etherize the Daphnia still more and turn it on its back. 

 Make a full-page drawing showing ventral view. Label carapace 

 with protective fringe of hair, both pairs of antennas, both 

 hepatic cceca, compound eye, ocellus, furca, anus, abdominal 

 bristles. 



