LACERTILIA. 363 



which have been variously referred to the Upper Devonian 

 and to the Trias, but which almost certainly belong to the latter. 

 Professor Huxley concludes that Tderpeton " presents not a 

 single character approximating it towards the type of the Per- 

 mian Protosauria, nor to the Triassic Rhynchosaurus, and other 

 (probably Triassic) African and Asiatic allies of that genus, 

 nor to the Mesozoic Dinosauria; still less can it be considered 

 a ' generalised ' form, or as, in any sense, a less perfectly organ- 

 ised creature than the Gecko, whose swift and noiseless run 

 over walls and ceilings, surprises the traveller in warmer cli- 

 mates than our own." In its dentition, Telerpeton seems to 

 have been " acrodont," and it differs from most existing Lizards 

 merely in having amphiccelous, and not proccelous, vertebrae. 



Hyperodapedon was originally discovered in the " Elgin Sand- 

 stones " along with Telerpeton, and it has since been found in 

 strata of Triassic age in India. It was described by Professor 

 Huxley as " a Saurian reptile about six feet long, remarkable 

 for the flattened or slightly concave articular surfaces of the 

 centra of its vertebrae, and for its well-developed costal system 

 and fore and hind limbs ; but more particularly characterised 

 by its numerous series of sub-cylindrical palatal teeth." Upon 

 the whole, Huxley concludes that Hyperodapedon is most 

 nearly allied to the living Sphenodon (Hatterid) of New Zealand, 

 upon the grounds that both " have amphicoelous vertebras 

 (those of the ancient reptile being far less fish-like than those 

 of the modern one, be it noted) ; both have beak-like prasmax- 

 illae, not anchylosed together ; both have the inferior zygoma 

 complete ; both have similarly-formed lower jaws ; in each a 

 single row of teeth in the mandible bites between two rows of 

 teeth fixed to a plate, which is formed by a union of the maxil- 

 la with the palatine bone a structure which is quite anom- 

 alous amongst Lacertilians j and, finally, in both, these teeth 

 wear down to the bone of the jaw by masticatory attrition." 



The genus Rhynchosanrus is in a doubtful position, but 

 may conveniently be considered 

 here. By Huxley its affinities 

 are regarded as being Lacertili- 

 an, but by Owen it is looked 

 upon as belonging to the Ano- 

 modontia, and as being most 

 nearly allied to Oudenodon. In 

 many points Rhynchosaurus ap- Fig. 3 t 5 . sk\i\\o(Rhynchosaurusarti- 

 proaches the existing Lizards, ^ < AfterOwen -> Tnas ' 



but its vertebrae are amphicoelous, and the structure of the 

 mouth is quite unlike that of any living Lacertilian. The skull 



