STRUCTURE OF HATTERIA 
spicuous in this animal as a clear mark on the top of the 
skull, is equally well shown in Jguana. There is nothing 
odd about the limbs or the tail. In short it is not sur- 
prising that, until its interior arrangements were made 
out, the Hatter1a was considered to be, what it certainly 
is not, a quite typical lizard. The fact is, that if we are 
to use the term lizard, that word must be decidedly put 
into inverted commas, as a token that its use is a con- 
cession to popular language. As a matter of fact there 
is no vernacular word which will express just exactly 
what the Hatteria is. Zoologists regard it as an early 
offshoot from the stem which produced not only lizards 
and snakes, but possibly, also, some other now existing 
types of reptiles. But we cannot call it either a pro- 
Lacertilian or a pro-reptile, though to the mind of the 
preseat writer it is mostly Lacertilian. We must content 
ourselves with calling it for the present simply by its 
name. The bony characters which distinguish Hatteria 
from lizards pervade the whole skeleton, and would 
require a little too much technical exposition for their 
due setting forth. But everyone can appreciate the 
fact that the lungs have not yet undergone the modifica- 
tions that they have in the true lizards and snakes. In 
the lizards, and much more in the snakes, the end of the 
lung farthest away from the entrance of the windpipe 
into it has partly or entirely ceased to have a respiratory 
function. Its walls are here thin and not so markedly 
honeycombed in structure as is the rest of the lung. 
Furthermore, in very many lizards the lung is com- 
pletely or partially divided into two or more compart- 
ments. In Hatteria the lung is an efficient lung through- 
out, and is a simple undivided sac. We are acquainted 
with a good many extinct relatives of Hatteria which 
carry us back to very early geological times. Its allies 
then flourished in Europe and in other parts of the world. 
Now the sphenodon is confined not only to New Zealand 
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