Euphausiacea
Eggs and larvae

Euphausiid species of the genera Thysanopoda, Euphausia, Meganyctiphanes, Thysanoessa have yolk-rich eggs which are freely laid in the water. The eggs are spherical and have a characteristic perivitellin space; the size of the embryos (exluding the perivitelline space) usually ranges from 0.25 to 0.5 mm (Zimmer and Gruner, 1956; Zelikman, 1961; Mauchline and Fisher, 1969). The largest embryos (on average ca. 0.6 mm and up to 0.8 mm in diameter) are found in Antarctic krill, Euphausia superba (although the egg size of some giant Thysanopoda species is not known) and are identifiable in Antarctic plankton samples (Fraser, 1936). Eggs of other species may be only tentatively ascribed to certain species commonly spawning in an area during a certain season.