272 REPTILES AND BATRACHIANS 



young being born alive, in the perfect form in the two 

 American species, at an advanced stage in the African. 



The Apoda are represented by only a single family, the 

 CceciliidcE^ of w^hich there are twenty- two genera and about 

 fifty species. The characters on which the genera are 

 based reside in the presence or absence of the scales, which 

 are embedded under the skin, the presence or absence of 

 eyes, the form of the tentacle, and the structure of the 

 skull. 



