PEDIGREE OF CCELENTERATES, 



147 



swimming-bell type and leading on to a terminus in Hydra, 

 It is certainly suggestive that we have jellyfish wholly 

 free {Pelagid)^ jellyfish with a sedentary larval life {Aurelia)^ 

 jellyfish predominantly passive (Lucernaria), and related 

 polypes (Sea- Anemones, etc.) which only occasionally rise 

 into free activity ; while in the other series we have medusoid 

 types always free, others which are liberated from (Campan- 

 ularian and Tubularian) sedentary hydroids, other (Sertu- 

 larian and Plumularian) zoophytes whose buds though often 

 medusoid-like are not set free, and finally, Hydra, which 

 though it may creep on its side, or walk on its head, is 

 predominantly a sedentary animal, without any youthful 

 free- swimming stage. 



GENERAL SCHEME OF CCELENTERATA. 



Predominantly Passive. 



Predominantly Active. 



Ctenophora. e.g., Beroe, 

 Venus' Girdle. 

 (Active climax.) 



II. Anthozoa or Actinozoa. 

 (Zoantharia) Sea-Anemones 



and related corals. 

 (Alcyonaria) Dead Men's 



Fingers and related 



corals. 



The embryos are free-swimming, and a 

 few adults also are locomotor. 



B. 



SCYPHO- 

 ZOA. 



r ( Scyphomedusae or 

 ■ \ Acraspeda. < 

 c. Adult Lucernarians 



usually attached. 

 h. Sedentary larval stage. 

 a. No fixed stage. 



c. Free embryos. 



b, Aurelia type of jellyfish. 

 a. Pelagia type of jellyfish. 



ANCESTRAL 



GASTR^A. 



^ 



A. 

 Hyijro- ^ 



ZOA. 



[I. No fixed stage. 

 I 2. No fixed stage. 



Many Hydrpid colonies. 

 (Campa,nularians and 

 Tubularians.) 

 Many Hydroid colonies, 

 whose reproductive per- 

 sons are not liberated. 

 Coralline MiUepores. 



1. Trachymedusae (always locomotor). 



2. Siphonophorse (locomotor colonies of 



modified medusoids). 



3. Liberated reproductive "persons*' of 



these colonies. 



4. No free stage, except as embryos. 



5. No kno^yn free stage. 



\6. Hydra without any specially locomotor stage. 



