XXIII] 



LACERTA VIVIPAKA 



577 



pubis ; all living Amniota also possess an obturator foramen but it 

 is not present in some of the oldest fossil Reptilia. 



On the hinder edge of the pubis 

 there is a projection which is called 

 the lateral process. In some ex- 

 tinct Reptiles this process was extra- 

 ordinarily long and ossified by a 

 distinct bone, which has been called 

 the postpubis. It is the post- 

 pubis which forms the so-called 

 pubis of Birds and Mammals. 



The most marked feature of the 

 hind-limb is the formation of a 

 sharply-marked "ankle" joint. 

 There is one place and one only 

 where the foot bends on the shank ; 

 whereas in Urodela bending can 

 occur at any place in the mosaic of 

 small bones which forms the tarsus. 



In the lizard all the three upper 

 bones of the tarsus are joined to 

 form a horizontal bar. The lower 

 bones have almost entirely coalesced 

 with the corresponding metatarsals, 

 only the third and fourth of the 

 series being distinguishable. Thus 

 the lizard has what has been called 

 an intertarsal joint an arrange- 

 ment which is highly characteristic 

 of many Reptiles and of all Birds. 



All trace of the division of the 

 abdominal muscles into 

 myotomes has disap- 

 peared, but in the region of the 

 ribs the innermost layer of the 

 muscles of the flanks still retains 

 the metameric arrangement and 

 consists of a series of bands con- 

 necting each rib with its successor. 

 These bands are termed the inter- 

 costal muscles and each consists of an external and an internal 

 s. & M. 37 



Viscera. 



FIG. 284. Open mouth of Varanus 

 indicus x 1. 



1. Posterior or internal nares. 

 2. Palatal folds. 3. Internal 

 opening of Eustachian tubes. 

 4. Opening of oesophagus. 5. 

 Glottis. 6. Tongue half pro- 

 truded. 7. Lip of lower jaw. 

 8. Teeth of upper jaw. 





