Question

Excretion in hemichordates takes place by which gland

Answer 1

During development, the gastrula changes to the planula (larva) in Aurelia (a jelly fish). The planula forms another larva, the scyphistoma. In winter and spring, the scyphistoma undergoes a process of transverse fission to form a number of ephyrae (larvae) so that the scyphistoma assumes the appearance of a pile of saucers.

The division of the scyphistoma larva of Aurelia into a number of ephyrae larvae by a series of transverse fissions is called strobilation. The ephyrae are detached and feed and grow. In due course of time the ephyrae metamorphose into jelly-fishes. Strobilation also occurs in the neck of Taenia.