1 140 



CLASS REPTILIA. 



Fig. 1042 



•Inner view of left ramus of the mandible of 

 Igtiana. 



Fig. 1043. — Vertebra of 

 europ&a, viewed from the haemal, an 

 terior, and lateral aspects ; from the 

 Upper Eocene of Hampshire, zs, Zy- 

 gosphene ; c, Costal tubercle. 



able from that of the existing Frilled Lizard ( Chlamydosaurus Kingi) 

 of the same country. 



Family Iguanid^e. — The Iguanoids are readily distinguished from 



the Agamidce by their 

 pleurodont dentition 

 (fig. 1042), and the 

 presence of zygosphen- 

 al articulations to their 

 vertebrae (fig. 1043). 

 Nearly all the genera 

 are now confined to 

 the New World. In the Upper Eocene (Oligocene) Phosphorites of 

 Central France there occur, however, fragments of jaws which have 



been referred to the typical American 

 genus Iguana; that term being used 

 in a wider sense than in recent herpet- 

 ology. Vertebrae also occur in the 

 approximately equivalent deposits of 

 * Hordwell in Hampshire (of which one 

 is represented in fig. 1043), which agree 

 in the presence of small zygosphenes 

 with those of existing Iguanas, and 

 have been provisionally referred to the French species. The name 

 Iguanavus has been applied to remains of a member of this family 

 from the Eocene of North America. 



Family Anguid^e. — The Anguidce are characterised by the pres- 

 ence of scutes roofing over the supratemporal fossae ; by the separa- 

 tion of the premaxillae and the nasals ; the more or less completely 

 pleurodont dentition ; and the presence of dermal scutes covered 

 with minute tubercles. The genus Ophisaurus (Pseudopus), in which 

 the limbs are either wanting or are reduced to rudiments of the pelvic 

 pair, is represented in the Middle Miocene of Gers, in France, and 

 the Lower Miocene of Rott, near Bonn ; some of the species having 

 been originally described under the name of Anguis. Propseudopus, 

 from the Middle Miocene of Steinheim, in Bavaria, is distinguished 

 from Ophisaurus by its stronger dentition and the presence of a 

 double row of teeth on the vomer. The genus Peltosaurus and the 

 allied Exostinus, of the Miocene of North America, may be included 

 in this family ; to which we may also refer several European and 

 American Upper Eocene genera which have been regarded as con- 

 stituting a distinct family under the names of Placosauridce and 

 Glyptosauridce. Among these Placosaurus (PalcBovaranus), from 

 the Upper Eocene of France and England, has teeth resembling 

 those of the Slow-worm (Anguis), which were originally regarded as 

 belonging to a Varanoid ; the vertebrae (fig. 1044) are not unlike 



