ORDER OF LIZARDS. 501 



arches of the vertebral column interlocked more extensively 

 than in other reptiles except the snakes. They swam rapidly 

 through the water by rapid undulations of their bodies aided 

 by the paddles. The skull was not so strong, though as 

 light as that of the serpents. " While the jaws were longer, the 

 gape was not so extensive as in serpents of the higher groups, 

 for the os quadratum, the suspensor of the lower jaw, though 

 equally movable and fastened to widely spread supports, was 

 much shorter than in them. But there was a remarkable 

 arrangement to obviate any inconvenience arising from these 

 points. While the branches of the under jaw had no natural 

 connection, and possessed independent motion, as in all ser- 

 pents, they had the additional peculiarity, not known else- 

 where among Vertebrates (except with snakes), of a movable 

 articulation a little behind the middle of each. Its direction 

 being oblique, the flexure was outwards and a little down- 

 wards, greatly expanding the width of the space between 

 them, and allowing their tips to close a little. A loose flexi- 

 ble pouch-like throat could then receive the entire prey 

 swallowed between the branches of the jaw ; the necessity of 

 holding it long in the teeth, or of passing it between the 

 short quadrate bones could not exist. Of course the glottis 

 and tongue would be forwards." The order became extinct 

 before the Tertiary Period. 



Order 3. Lacertilia. The existing lizards or Saurians are 

 the survivors or descendants of a multitude of forms, many 

 colossal in size, which characterized the Permian and Meso- 

 zoic periods ; while the extinct forms of reptiles were in 

 many cases synthetic types, with affinities to fishes, Am- 

 phibians, and even birds. The group as now existing is well 

 circumscribed. 



Most lizards have cylindrical bodies, usually covered with 

 small overlapping scales, with a long, slender tail, and general- 

 ly two pairs of feet, the toes long and slender, and ending in 

 claws. They run with great rapidity, and are active, agile 

 creatures, adorned with bright metallic colors, in some cases 

 green or brown, simulating the tints of the vegetation or 

 soil on which they live ; some are capable of changing their 

 color at will, as in the chameleon and Anolis ; this is due to 



