SNAKES. 175 
There are some snake-like Lizards such as the Glass Snake 
(Ophisaurus apus, Fig. 42) and the Slowworm (Anguis fragilis, 
Fig. 43), and there are Lizard-like Snakes, for example, the 
Blind Snakes (Z'yphlopidw) and the Short-Tails (Zortricide), 
these Snakes having many characteristics, which will be briefly 
referred to, of a Saurian type. But the former (the Snake-like 
Lizards) may be known from all Snakes—and the latter (the 
Lizard-like Snakes) from all Lizards by the formation of the jaws. 
The mouth of Ophidians, owing to this formation, is capable as a 
rule of very great extension. However, some Snakes can open 
the mouth, in proportion to their size, much wider than others ; 
consequently there are the Hurystomata, or wide-mouthed Ser- 
pents, and the Angzostomata, or small-mouthed Serpents. Never- 
theless, the looseness of the jaws, which is characteristic of all 
Snakes, is only rather less developed in some families than in 
others. 
The jaws, therefore, of all Snakes are very loosely connected. 
The two halves of their lower jaw are united in front, at the chin, 
by an elastic ligament or string, instead of being joined together 
by a bony formation as in most other animals. The other jaws of 
these Reptiles are also connected very loosely by means of elastic 
ligaments, viz., the maxillaries or upper jaws, and the palatine 
jaws, the bones of the palate being generally provided with teeth. 
The bones called the pterygoid bones are movable, too, and can 
be pressed forwards and outwards. The lower jaws, or mandibles, 
are joined to, or suspended from, the skull by means of bones, 
which conduce to the expanding powers of the gullet. These 
bones from their position are called tympanic bones. 
Most Snakes may be said to have, therefore, six jaws, viz., the 
two lower, the mandibles, four upper, ¢.e., two maxillaries and two 
palatine jaws; but Pythons may be said to possess a seventh, for 
a bone, known as the intermaxillary, is in their case provided 
with from two to four teeth. This extra jaw, no doubt, is very 
useful in the seizing of prey. 
For the reasons just mentioned a Snake is able not only to open 
its jaws exceedingly widely vertically, but also laterally. Each 
jaw is able to move independently of the other. All the jaws of a 
non-poisonous Snake are furnished with nunierous fine teeth, 
