RHYNCIIOCHril. ILIA 177 



Sphcnodon than in any other living land animals except the gecko 

 lizards. Upon the whole the tuatera is the most old-fashioned of 

 living reptiles, and in consequence it has nearly lost out in com- 

 petition with new things. 



With these living tuateras we have nothing further to do, since 

 they are land animals, living about the beaches of the New Zealand 

 islands, and only occasionally venturing into the water, hiding from 

 their enemies in the holes in the rocks. But, from some of their 

 antecedents, from some of their direct forbears perhaps, there have 

 gone ot^ at different times various branches, whose descendants 

 wandered into foreign lands or into foreign places, and lived and 



Fig. 85. — Sphowdon punciatum, or tuatera. (From specimen in the Yale Uni- 

 versity museum.) 



flourished for a brief time and then became extinct. Some of these 

 went down into the water and became more or less aquatic in 

 habit; some, indeed, changed their forms and habits so greatly 

 that they are often, perhaps rightly, segregated into different 

 orders. Whether or not they should be called Rhynchocephaha 

 matters Httle. however. It is merely a matter of opinion as to 

 how great the changes should be in order to entitle the offspring 

 to a genealogical tree all its own. Of these branches there are 

 two, whose relationships seem to be definite, the Choristodera and 

 Thalattosauria, though there is more doubt about the latter than 

 the former. A third group, that included Pleiirosaiirus. seems, from 



