Carefully arrange the apical organ on a slide and prepare a wetmount. Be sure the epidermis is not folded over the apical organ. Look for the statolith , four balancer tufts of cilia upon which the statolith rests, and a ciliated groove to each comb row. Gametes are shed to the sea via numerous tiny gonopores in the comb rows. In most species fertilization is external.
Cleavage is indeterminate and spiral.
Development is direct without metamorphosis but includes a characteristic cydippid larva which resembles the adult. As is the case in the Scyphozoa and Anthozoa, the gut is divided into a central digestive region where extracellular digestion occurs and a peripheral distributive portion. The pharynx is the major extracellular digestive chamber and the canals are the distribution, or fluid transport, system. The gastrodermis lining the distributive canals is composed of both ciliated and phagocytic cells. Extracellular digestion begins in the pharynx with the secretion of hydrolytic enzymes.