SKELETON 



The skeleton of a primitive type in most of its par- 

 ticulars. It represents the early adaptations of the tetrapod 

 to land life, combined with many characters that are re- 

 lated to water living. 



For convenience the skeleton is divided into three divi- 

 sions; the axial consisting of the skull, vertebral column, 

 ribs and sternum ; the appendicular, consisting of the limbs 

 and their girdles ; and the visceral consisting of the supports 

 of the gills and the parts deprived from them. 



Axial Skeleton 



Note the divisions of the axial skeleton and the position 

 of the limbs in relation to the vertebral column. The ribs 

 extend to the head with the exception of the first cervical 

 where they have been lost. 



SKULL 



The flat platybasic skull contains a reduced number of 

 bones, some having been lost. There is also a part that re- 

 mains cartilage. This may be studied by boiling the skull 

 gently and manipulating with a needle. This should be 

 done after the bones of the skull have been studied. 



Drawing 2. Make a drawing of the dorsal surface X 10. 



Dorsally the median series consists of the premaxillae, at 

 the anterior end followed by the frontals and parietals. 

 All of these bones are paired. The exoccipitals each supply 

 one of the two condyles present in the amphibia. The 

 supraoccipital is not ossified. From the dorsal side, the 



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