Practice question

Ctenophore embryogenesis indirect in most planktonic species fertilized egg undergoes biradial cleavage hatches into characteristic cydippid larva free-swimming ovoid transparent form resembling miniature adult Order Cydippida with pair long branched tentacles housed within lateral sheaths eight rudimentary comb rows beating apical statocyst present at aboral pole. Cydippid serves as both larval stage and ancestral morphotype reflecting primitive biradial architecture from which lobate ribbon and beroid forms derive through growth. Some lobate retain cydippid features into juvenile stage few species direct developers lacking cydippid. Name derives genus Cydippe illustrating tentaculate juvenile stage emblematic phylum life history and dispersal in oceans globally.