VERTEBRATA. 3807 
4. Batrachians include all the well-known tailless Am- 
phibians, as Frogs and Toads. They have a moist, naked 
skin, ten vertebrae, 
and no ribs. As 
they breathe by 
swallowing the air, 
they can be suffo- 
cated by holding Fig. 286.—Red Salamander (Pseudotriton ruber). 
the mouth open. Ce fi 
They have four limbs —the hinder the longer, and the 
first developed. They have four fingers and five toes. 
The tongue is long, 
and, fixed by its an- 
terior end, it can be 
rapidly thrown out as 
‘an organ of prehen- 
sion. The eggs are 
= laid in the water en- 
Fie. 287.—Frog (Rana). 
veloped in a glairy 
mass; and the tadpoles resemble the Urodelans, till both 
gills and tail are absorbed. Frogs (/@ana) have teeth in 
the upper jaw, and webbed feet; Toads (Bufo) are higher 
in rank, and have neither teeth nor fully webbed feet. 
The former have been known to live sixteen years, and 
the latter thirty-six. 
Crass III.—Reptilia. 
These air-breathing, cold-blooded Vertebrates are dis- 
tinguished from all Fishes and Amphibians by never hay- 
ing gills, and from Birds by being covered with horny 
scales or bony plates. The skeleton is never cartilaginous; 
and the skull has one occipital condyle. The vertebree are 
ordinarily concave in front; and the ribs are well devel- 
oped. With few exceptions, all are carnivorous; and teeth 
are always present, except in the Turtles, where a horny 
