STRUCTURE OF HATTERIA 



spicuous in this animal as a clear mark on the top of the 

 skull, is equally well shown in Iguana. 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 Hatteria 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 

 present 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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