8 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



Additional scientific names used for convenience in grouping the classes of vertebrates 

 are: 



Ichthyopsida. This term, meaning fishlike animals, includes the two classes, Pisces and 

 A mphibia. 



Sauropsida. This term, meaning reptile-like animals, includes the two classes, Reptilia 

 and Aves. 



Anamniota or Anamnia. This term includes the classes Pisces and Amphibia and refers 

 to the fact that their embryos are naked. 



Amniota. This embraces the three classes, Reptilia, Aves, and Mammalia, and refers to 

 the fact that the embryos of these groups are covered by a membrane, the amnion. 



Acraniata or Acrania. This name is synonymous with Cephalochordata and is derived from 

 the absence of the skull in Amphioxus. 



Craniata. This term is synonymous with Vertebrata and refers to the fact that all verte- 

 brates possess a skull. 



Agnathostomata. This term, meaning without jaws, is synonymous with Cydostomata. 



Gnathostomata. This name, meaning jawed, includes all of the classes of vertebrates, 

 except Cydostomata. 



Tetrapoda. This term, meaning four footed, includes all of the land vertebrates, i.e., 

 the classes Amphibia, Reptilia, Aves. and Mammalia. 



