320 GEOGEAPHICAL AND GEOLOGICAL DISTEIBUTION. 



to Montana and Virginia. Upwards of a hundred species have 

 been described. 



New Zealand for rather the small islands oif the northeast coast) 

 possesses a remarkable lizard in the genus Hatteria or Sphenodon, 

 which in many points of structure departs from the type of true 

 lizards, and approximates it to an ancient lost form from the Trias, 

 the genus Hyperodapedon. 



The earliest known representative of the Lacertilia is Protero- 

 saurus, from the Perinian deposits of Germany and England, which 

 appears to be most nearly related to the monitors, from which, 

 however, it differs in its thecodont dentition.* Hyperodapedon 

 (which, with the contemporaneous Rhynchosaurus, and the recent 

 Hatteria, is by some authors constituted into a distinct order, 

 Rhynchocephala) and the acrodont genus Telerpeton (Elgin lime- 

 stones of Scotland) appear in the Trias, and are succeeded in the 

 deposits of Jurassic age by a niunber of more or less obscurely 

 defined genera (Geosaurus, Homoeosaurus, Acrosaurus, Anguisau- 

 rus), whose relationships with modem forms are in most cases not 

 clearly indicated. Lacertilian remains are not abundant in the Cre- 

 taceous deposits, and such as have been preserved are mainly in a 

 fragmentary condition ; thfe recent genus Hydrosaurus, one of the 

 monitors, is indicated. In Tertiary strata the remains become nu- 

 merous, and belong in considerable part to modern types. Frag- 

 mentary skeletons from the European Miocene deposits have been 

 referred to Iguana and Lacerta, and, doubtfully, also to Scincus 

 and Anguis. — No true lacertilians are known from American de- 

 posits older than the Eocene. The western lake-basins of this age 

 have yielded numerous remains, which are referable to a number 

 of distinct genera — Glyptosaurus, Iguanavus, Oreosaurus, Tino- 

 saurus, Saniva — and some of which appear to have survived into 

 the Miocene. Among the very limited number of forms of this 

 period may be mentioned Peltosaurus, doubtfully referred to the 

 Gerrhonotidse, and Cremastosaurus, the latter of about the size of 

 the horned-toad. 



Ophidia. — The distribution of the Ophidia is very similar to 

 that of the Lacertilia, the order being most numerously represented 



* Professor Seeley believes it probable that Protcrosaurus is a dinosaur. 

 (Piiillipa, " Manual of Geology," edited by Etheridge and Seeley, 1885.) 



