540 HISTORY OF THE HUMAN BODY 



Division II. Gnathostomata. 

 Super-Class I. Ichthyoidea. 

 Class I. Pisces. 



Sub-Class I. Elasmobranchii. 



Order i. Pleuropterygii (Cladoselache) . 

 Order 2. Ichthyotomi (P I eur acanthus). 

 Order 3. Acanthodii (A cant hod es, Diplacanthus). 

 Order 4. Selachii. 



Sub-Order I. Squall (sharks, dog-fish). 

 Sub-Order 2. Raiae (skates). 

 Sub-Class II. Holocephali.* 



Order i. Chimaeroidei * (Chimcera). 

 Sub-Class III. Dipnoi.* 



Order i. Sirenoidei * (Protopterus, Ceratodus). 

 Order 2. Arthrodira (Coccosteus, Dinichthys). 

 Sub-Class IV. Teleostomi. 

 Order i. Crossopterygii.* 



Sub-Order i. Haplistia (Tarrasius). 



Sub-Order 2. Rhipidistia (Holoptychius; Oste- 



olepis). 



Sub-Order 3. Actinistia (Ccelacanthus ; Undina). 

 Sub-Order 4. Polypteroidei * (Polypterus; Cala- 



moichthys). 

 Order 2. Actinopterygii. 



Sub-Order i. Chondrostei * (Palaoniscus ; Aci- 



penser, sturgeon). 

 Sub-Order 2. Protospondyli * (Lepidottts; Eu- 



gnathus; Amia, bow-fin). 

 Sub-Order 3. ^Etheospondyli * (Aspidorhynchiis; 



Lepisosteus, gar-pike). 

 Sub-Order 4. Isospondyli (Leptolepis; herring; 



salmon; trout). 

 Sub-Order 5. Eventognathi (carp ; minnow; 



sucker). 



Sub-Order 6. Nematognathi (siluroids, e.g. bull- 

 heads, cat-fish, etc.). 

 Sub-Order 7. Haplomi (pike; killifish). 

 Sub-Order 8. Apodes (eels). 

 Sub-Order 9. Synentognathi (flying-fish). 



