CLASSIFICATION OF THE ANIMAL KINGDOM. 93 



CLASS V.— CEPHALOPODA. 



1. DlBRANCHIATA . 



2. Tetrabraxchiata 



loligo, Sepia, Spirilla, Octopus, * Belemnites. 

 Nautilus, * Orthoceras, * Ammonites, * Bacu- 

 lites. 



TUNICA TA. 



[The Tunicates or Ascidians occupy a position intermediate between Mollusca 

 and Vertebrata. No fossil forms are known, except in late Tertiary deposits.] 



VERTEBRATE ANIMALS} 

 SUB-KINGDOM VII.— VERTEBRATA. 



Pharyngobranchei 



CLASS I.— LEPTOCARDIA. 



Branchiostoma (Amphioxus). No fossil forms. 



CLASS II.— PISCES (FISHES). 



1. Cyclostomi (Marsipo 



braxchii . 



2. Elasmobraxchei. 



a. * Ichthyotomi 



b. Selachii 



(1) Tectospondyli 



(2) Asterospondyli 



3. Chim.eroidei 

 4.. Dipnoi 



5. Gaxoidei. 



a. * Cephalaspidea 



b. * Placodermata 



c. * Acanthodea 



d. Crossopterygea 



e. Acipenseroidea 



f. Lepidosteoidea 



g. Amioidea 



6. Teleostei. 



a. Physostomi . 



b. Anacanthini . 



c. Pharyngognathi 



d. Acanthopterygii 



e. Lophobranchii 



f. Plectognathi . 



Myxine, Petromyzon. No fossil forms. 



Pleurae ant h us. 



Cestracioji, Lamna, Spinax. 

 Squatina, Raia. 

 C/i imcera, * Isch iodus . 

 lepidosiren, Ceratodus. 



Cephalaspis, Pteraspis. 

 Ptei-ichthys, Coccosteus. 

 Aeant/iodes, Diplacanthus. 

 * Holopty 'chins, Polypterus. 

 Acipenser, * Palceoniscus. 

 Lepidosteus, * Dapedius. 

 Amia, * Caturus. 



Salmo, Esox, Silurus. 

 Gadus, Rhombus. 

 Labrax, * Phyllodus. 

 JMugil, Perca. 

 Solenostoma, Hippocampus. 

 Balistes, Diodon. 



CLASS III.— AMPHIBIA (AMPHIBIANS). 



Labyrixthodontia. 

 a. Branchiosauria 

 />. /Estopoda 



c. Microsauria . 



d. Labyrinth odontia Vera 



Protriton. 



Dolichosoma, Oph iderpeton. 

 Urocordylus, Cerateipeton. 

 Archeeosaurus, Mastodonsaurus. 



1 The classification of Vertebrate Animals here followed is, in the main, the 

 one which has been adopted in the latest of the Catalogues of fossil Vertebrates 

 issued by the Trustees of the British Museum. 



