246 
NATURAL HISTORY. 
while Regulus led his army along the banks of the river 
Bagrada, in Africa, an enormous serpent disputed his pas- 
sage over. We are assured by Pliny, who says that he 
himself saw the skin, that it was an hundred and twenty 
feet long, and that it had destroyed many of the army. At 
last, however, the battering engines were brought out 
against it ; and these assailing it from a distance, it was 
soon destroyed. 
With respect to their conformation, all serpents have a 
very wide mouth, in proportion to the size of the head ; and, 
what is very extraordinary, they can gape and swallow the 
head of another animal which is three times as big as their 
own. To explain this, it must be observed, that the jaws 
of this animal do not open as ours, in the manner of a pair 
of hinges, where bones are applied to bones, and play upon 
one another ; on the contrary, the serpent’s jaws are held 
together at the roots by a stretching muscular skin; by 
which means they open as widely as the animal chooses to 
stretch them, and admit of a prey much thicker than the 
snake’s own body. The throat, like stretching leather, 
dilates to admit the morsel ; the stomach receives it in 
part; and the rest remains in the gullet, till putrefaction 
and the juices of the serpent’s body unite to dissolve it. 
As to the teeth, we shall speak more of them when we come 
to treat of the viper’s poison. The tonguein allthese animals 
is long and forky. It is composed of two long fleshy sub- 
stances, which terminate in sharp points, and arc very pliable. 
Some of the viper kind have tongues a fifth part of the length 
of their bodies; they are continually darting them out, but 
they are entirely harmless, and only terrify those who are 
ignorant of the real situation of their poison. 
The skin is composed of a number of scales, united to each 
other by a transparent membrane, which grows harder as it 
grows older, until the animal changes it, which is generally 
done twice a year. This cover then bursts near the head, ana 
the serpent creeps from it, by an undulatory motion, in a new 
skin, much more vivid than the former. As the edges of the 
foremost scales lie over the ends of their following scales, so 
those edges, when the scales are erected, which the animal 
has a power of doing in a small degree, catch in the ground, 
like the nails in the wheel of a chariot, and so promote and 
facilitate the animal’s progressive motion. The erecting 
these scales is by means of a multitude of distinct muscles, 
with which each is supplied, and one end of which is tacked 
to the middle of the foregoing. 
This tribe of animals, like that of fishes, seems to have no 
