548 HISTORY OF THE HUMAN BODY 



SYNOPSIS OF VERTEBRATA (living forms alone). 



Class I. Pisces. 



Sub-Class I. Selachii. 



Sub-Class II. Holocephali (often considered with the 



previous group). 

 Sub-Class III. Ganoidei. 

 Sub-Class IV. Teleostei. 

 Sub-Class V. Dipnoi. 

 Class II. Amphibia. 

 Order i. Urodela. 

 Order 2. Gymnophiona. 

 Order 3. Anura. 

 Class III. Reptilia. 



Order i. Chelonia. 



Order 2. Lacertilia (including Sphenodon). 

 Order 3. Ophidia. 

 Order 4. Crocodilia. 

 Class IV. Aves. 



Sub-Class I. Ratitse (running birds; with flat breast- 

 bone, e.g. Ostrich). 

 Sub-Class II. Carinatse (flying birds; with keeled 



breast-bone). 

 Class V. Mammalia. 



Sub-Class I. Prototheria. 

 Order i. Monotremata. 

 Sub-Class II. Eutheria. 

 Super-Order i. Didelphia (Marsupialia). 

 Super-Order 2. Monodelphia (Placentalia). 

 Order i. Edentata. 

 Order 2. Insectivora. 

 Order 3. Rodentia. 

 Order 4. Cetacea. 

 Order 5. Sirenia. 

 Order 6. Ungulata. 

 Order 6a. Proboscidea (occasionally separated from 



the Ungulata). 



Order 6b. Hyracoidea (occasionally separated from 

 the Ungulata). 



