Female cladocerans have a large open brood chamber located under the dorsal carapace in the posterior thoracic region. This is the where eggs are deposited and brooded until they complete embryonic development and become juvenile cladocerans. At this time they are released and assume an independent existence. The brood chamber of your specimen may be filled with eggs or embryos. Try to determine which and look at the specimens of your classmates to see other life history stages.
Females produce two types of eggs.
Summer eggs have little yolk and develop parthenogenetically, without fertilization. Summer eggs are carried in the brood chamber at least until they hatch and in some species until they are sexually mature and have young of their own. Winter eggs, on the other hand, are very yolky and are produced only after fertilization. These eggs are also released into the brood chamber, where they are fertilized. Winter eggs, unlike those of summer, are not brooded rather are immediately released by the female, either enclosed in a protective cuticular ephippium or naked.