296 THE VIVARIUM. 
The Ecaudata are divided into the two sub-orders—(1) Phaner- 
oglossa (possessors of a tongue), and (2) Aglossa (lacking a tongue) 
—and fourteen families, twelve belonging to the former sub- 
order and two to the latter. The Cawdata are arranged in four 
families ; and the Apoda consist of only one family. All the 
Batrachians, when they have completed their metamorphosis, 
partake of animal food, which they seize alive, such as insects, 
worms, slugs, and sometimes (in the case of the largest Batra- 
chians) mice, birds, fish, and the like. Many of the Batrachians, 
during a portion of their tadpolehood, are vegetable feeders. 
Before I describe any particular species of the Batrachia, 
perhaps it will be wise for me to sketch briefly the life of 
the Common Frog (which is very similar to that of the greater 
number of these creatures) from the time it leaves the egg until 
the completion of its metamorphosis. 
In early spring, in England, sometimes during the latter part 
of January and in February, but oftener in March, frogs congre- 
gate in fresh water, such as in the stiller parts of rivers and 
streams, in lakes, ponds, and small pools, for the purpose of de- 
positing their eggs. The eggs are fertilised by the male as they 
are ejected by the female. 
At first they are little, almost black, bodies (Fig. 77a), en- 
closed in a glutincus envelope, into which a quantity of water is 
presently absorbed. When this absorption has taken place 
(Fig. 77b), the eggs may be likened to a kind of jelly, in which 
small shot have been imbedded. These shot-like bodies are the 
yolks of the eggs. 
Frogs’ spawn, as the eggs are commonly called, is found in 
masses, while that of Toads is regularly arranged in strings of 
two rows each. The eggs hatch in from four days to a month, or 
even more, according to the temperature of the water in which 
they are. 
In all probability few things in Natural History are more in- 
teresting than the development of a tailless Batrachian from the 
egg. Some of the eggs of Frogs (and Toads), a short time after 
they have been deposited, assume a bluish-white colour, which 
shows that they are unfertile, and therefore of course that they 
will not hatch. The other eggs, sooner or later, according to the 
