Chap. II. CLASSIFICATIONS OF ACALEPHS. 149 



CLASSIFICATION OF GEGENBAUR, 1856-1859. 



Gegenbaur is the last author to whose systematic views I have to alkide, as far as they relate to 

 the Acalephs in general : later authors have only considered parts of the subject. He, like most recent 

 German writers, ado])ts the primary division of the Radiata into Coelenterata and Echinodermata, proposed 

 by Leuckart, and in his Textbook of Comparative Anatomy subdivides the Coelenterata into three classes : 

 PoLTPi, Hydromedusida, and Ctenophoea. Here the Hydroids are all referred to the class of the 

 Ilydromedusida, with the sole exception of Lucernaria, which is left among the Polyps. The Hydro- 

 medusida themselves are divided in the following manner : — 



1st Order. Htduoidea : Coryne, Syncoryne, Ilydractinia, Sertularia, Pennaria ; — Campanularia, Eu- 

 dendrium, Tubularia. 



2d Order. Medusida : 1° Craspedota: Oceania, Sarsia, Lizzia ; — Geryonia ; — JEquorea ; — iEgineta, 

 Cunina. 2° Acraspeda: Pelagia, Aurelia, Chrysaora ; — Ehizostoma, Cas- 

 siopeia. 



3d Order. SirnoNOPHORA : Velella, Porpita ; — Diphyes, Abyla ; — Agalma, Physophora, Physalia. 



To tlie class Ctenophora the genera Cestum, Cydippe ; — Mnemia, LeSueuria ; — Eucharis ; — and 

 Beroe, are referred. But Gegenbaur had already published a more special account of his view of the 

 Ctenophora in 1856, in the " Archiv fiir Naturgeschichte," p. 163, in which he adopts the following 

 families : — 



C a 1 1 i a n i r i d » : Callianira. 



Calymnidfe : Calymna, Mnemia, Axiotima, Bolina, Eucharis, Leucothoe, Alcinoe, Chiaja, LeSueuria, and 



Euramphiea. 

 C e s t i d a> : Cestum. 

 Cydippida? : Neis, Ocyroe, Mertensia Less., Anais, Eschscholtzia, Mertensia Gegenb., Janira, Cydippe. 



Pleurobrachia, Beroe Mert., Owenia. 

 Beroidffi : Beroe (Idya, Cydalisa, Medea). — Sicyosoma. 



In 1857, Gegenbaur publislied a special paper upon the Discophora? in the Zeitsehrift fiir wissen- 

 schaftliche Zoologie, in which he admits two great divisions, corresponding to the Phanerocarpa and 

 CryplocarpcB of Eschscholtz, and to the Sleganophthalmata and Gymnopldhahnata of Forbes, as follows : — 



Acraspeda, with four families : — 



Rhizostomida! : Rhizostoma, Cephea, and Cassiopeia. 



Medusidw: Aurelia, Sthenonia, and Cyanea. 



Pelagidas : Chrysaora, Pelagia, and Nausithoe (Octogonia). 



Charybdeidaj : Charybdea. 

 Craspedota, with seven families : — 



Oceanidas : Oceania, Saphenia, Turris, Sarsia, Modeeria, Bougainvillea, Lizzia, Cyta'is, Zanelea, 

 Steenstruppia, Euphysa, Cladonenia, Willsia, Chrysomiira ; with five sub-families, Oceanida- proper, 

 Sarsiadfe, Boiigaiiivillida, Willsiada, and Cladonemida: 



Thaumant ida> : Thaumantias, Staurophora, Tiaropsis, and Tinia. 



iEquorida' : JEquorea, Mesonema, Stomobrachium. 



Eucopida; : Eucope, Sminthea, Eurybiopsis, Aglaura. 



Trachynemidffi : Trachynema, Rhopalonema. 



Geryonida; : Geryonia, Liriope. 



j3Eginida3 : Cunina, iEgineta, jEgina, iEginopsis, Polyxenia. 



