Phylum Cnidaria and Phylum Ctenophora

Kingdom Animalia 
  Subkingdom Eumetazoa
    Phylum Cnidaria
      Class Hydrozoa: Obelia, hydra, Physalia physalia, Vellela velella
       Class Cubozoa: Carybdea sp.
       Class Scyphozoa: Aurelia aurita
       Class Anthozoa
         Subclass Octocorallia: Lophogorgia chilensis, Renilla kollikeri
         Subclass Hexacorallia: Balanophyllia elegans, Anthopleura sola
         Subclass Ceriantipatharia: Pachyerianthus fimbriatus

     Phylum Ctenophora 
        Class Nuda: Beroe
        Class Tentaculata: Pleurobrachia bachii
       

Life cycle of Obelia 
Medusa--> Sperms/ Eggs--> Zygote-->Blastula--> Free-swimming planula larva--> Settles down to start new colony--> Obelia Colony

Source: http://wanderinweeta.blogspot.com/2011/10/obelia-and-very-messy-limpet.html

Life cycle of Aurelia

Medusa--> Sperms/Eggs--> Zygote--> Blastula--> Cilliated planula larva--> Scyphistoma-->Early Strobila-->Strobila-->Ephyra

Source: http://192.171.193.133/detail.php?sp=Aurelia

 Important terms and cell types
Cnidocytes, Diploblastic, Ectoderm, Endoderm

Source: Lab manual of Professor Blake Barron