THE AGE OP NEW ZEALAND. 
427 
is more nearly allied to tlie extinct form hyperodapedon, 
than to any saurian now in existence, from its very extra- 
ordinary internal structure. This lizard, which is seldom 
more than eighteen inches in length, takes its name from 
the teeth-like ridge on its back ; it was formerly very abun- 
dant, but is now nearly extinct, probably it was once preyed 
upon by the moa, and when it was less numerous became 
one cause of its decrease ; it is now only found on the small 
islands near the main land, which are uninhabited. 
The bird preceded the animal, and the remarkable absence 
of all land animals in New Zealand, except a diminutive rat, 
presents another point of resemblance to the liassic age. 
From the general presence of wingless birds on every 
continent, and on almost every lone island in the southern 
hemisphere, there is strong evidence that a grand continent 
existed in the bird age, from the destruction of which New 
Zealand escaped, and so preserved its primitive tenants ; 
but the disrupted fragments of that continent being widely 
severed from other lands, received none of the varied races 
of animals which later epochs called into existence in other 
parts of the world. 
The marsupial races still surviving in Australia seem to 
point to a still later separation of that insular continent from 
the grand regions of the earth : but it may be observed that 
the southern half of the globe still contains the largest 
organic developments, the elephant, rhinoceros, hippopo- 
tamus, and the sole existing species of the tapir, an order of 
which Europe has only the pig as its representative, whilst 
in the southern hemisphere none of the domesticated animals 
of the other half seem to be, properly speaking, indigenous ; 
it is there likewise the reptile and saurian attain their greatest 
dimensions; indeed, an ancient type of animal form seems there 
to prevail, and this applies to the sea as well as to the land. 
Many kinds of fish or shells being either identical, or more 
nearly allied to those of the carboniferous than of the present 
age ; in particular may be mentioned the placoids, which 
form the first order of fishes in the arrangement of Agassiz ; 
they are characterised by having their skin covered irregu- 
