MENOBRANCHUS AND LACERTA 
covers the eggs of the lizard. The young lizard emerges 
from the egg a fully formed lizard; the young meno- 
branch is not so identical with its parents, and is there- 
fore hatched at an earlier stage and therefore again 
sooner. It has a tadpole-like form and is a larva, the 
definition of which term will be dealt with presently. 
Excepting fora general similarity in form, every point 
almost in external structure, not to mention internal 
structure, differentiates the Menobranchus from the 
Lacerta ; and if all lizards and other reptiles showed the 
same differences from all other amphibians there would 
obviously be no difficulty in defining the two groups. 
But when we go farther afield, we shall find that most 
of the points of difference break down. To amend the 
diagnoses we will recur to the characters used in exactly 
the same order. While most amphibians are mostly 
aquatic, there is one group, that of the Ccecilians, 
which are worm-like creatures burrowing in the soil, 
and the tree-frogs spend at least most of their time, 
as their name denotes, upon trees and other plants, 
while toads are mostly land dwellers. Per contra the 
crocodiles among reptiles are aquatic, as are more en- 
tirely so the marine turtles. Certain lizards, such as 
the Australian Leseuer’s lizard (Physignathus) spend a 
large portion of their time in water. Plenty of other 
examples might be urged in proof of the impossibility 
of separating reptiles and amphibia by their aquatic or 
terrestrial habit. Nor can diurnal or nocturnal habits 
be utilized. Both reptiles and amphibians furnish us 
with examples of nocturnal and diurnal creatures. 
The soft body of the amphibian, on the other hand, isa 
character which is very widely spread, as is the scaly 
body of the reptile. But here again there is not an 
absolute line of demarcation. The underground and 
burrowing lizard Amphisbena has a softish body, though 
it is true that it does not possess the numerous slime 
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