130 REPTILES AND BIRDS. 
CROCODILES. 
The Shielded Saurians, as Duméril designates the largest of living 
species of that order of Reptiles, have the body depressed, elongated, 
and protected on the back with a solid carinated shield or buckler ; 
the tail longer than the trunk, compressed laterally, annulated and 
crested above ; possess very short legs ; the toes of the posterior feet 
united, or web-footed, each foot having three claws only; head 
depressed and elongated into a muzzle; the gape of the mouth 
extending back beyond the skull; tongue fleshy, adherent; teeth 
conical, simpie, hollowed at the base or towards the root, unequal in 
length, and ina single row. Such is a brief summary of the family, 
by Duméril and Bibron. 
If the eagle is the king of the air, the lion the despot of the forest, 
and the whale the monarch of the deep, the crocodile has for the 
exercise of his undisputed control the(shores of tropical seas and 
rivers.)( Living on the confines of land and water,)\this formidable 
reptile is the scourge of those human beings who are compelled to 
reside near its haunts, for it surpasses the tiger, lion, or eagle, in 
its power of destruction. / 
Crocodiles have the head depressed and elongated into a muzzle, 
in the front of which the nostrils are seen close to a fleshy tubercle, 
and furnished with movable valves. The mouth opens up to the 
ears ; the jaws are of commensurate length, and are armed, as we 
have seen, with conical-pointed teeth, bent back, and disposed in such 
a manner that when the mouth is closed they pass one under the 
other. These teeth are implanted in a single row, and continually 
maintained perfect by an organic system which ensures their immediate 
reparation ; for, each tooth is hollowed at the base in such a manner 
as to form the cell or sheath for its successor. ‘The new tooth, ° 
presses on underneath the old one, so that the first is developing 
while the second is decaying. In some species the front teeth of the 
lower jaw are so long and sharp that they perforate the edge of the 
upper jaw and appear above the muzzle when the mouth is closed. 
Baron Cuvier says, ‘The lower jaw being continued behind the 
cranium, the upper one appears to be movable.” The mouth is 
without lips, consequently, whether walking or swimming, their teeth 
are visible. 
This conformation gives to the Crocodile a terrible and alarming 
aspect, increased by its eyes, which are placed obliquely and close 
together. (Its tail is long, tapering, and fiat on the sides like an oar ; 
enabling it to direct its course through the water, and swim with 
