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 Saurtans 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 
