ORDER SQUAMATA. 



1139 



known form appears to be Macellodus (with which Saurillus is 

 either identical or very closely allied), from the English Purbeck ; 

 a small Lizard with pleurodont dentition, dermal scutes, and pro- 

 ccelous vertebras. Adriosaurus is a larger form from the Lower Green- 

 sand of Austria, also having dermal scutes and proccelous vertebras, 

 but of which the dentition is unknown. An allied Continental 

 Mesozoic form has received the name of Hydrosaurus, which is, 

 however, a synonym of Varanus. In the Cambridge Greensand 

 an imperfect femur and a vertebra indicate a Lizard of the size of 

 some of the existing Monitors, but of which the affinity cannot even 



Fig. 1041. — The common Skink {Scincus officinalis). Reduced. 



be conjectured. In the English Chalk occur the imperfectly known 

 genera Coniasaurus and Raphiosaurus ; the former having expanded, 

 and the latter acute teeth. 



Here also may be mentioned several genera from the Tertiaries 

 of North America, of which the family position cannot yet be de- 

 termined. The Eocene forms have been named Tinosaurus and 

 Thinosaurus, and those from the Miocene Aciprion, Platyrhachis^ 

 and Cremastosaurus. JYotosaurus, from the Tertiary of Brazil, has 

 amphiccelous vertebrae, and may be a Rhynchocephalian. 



Family Agamid^e. — The Agamoid Lizards constitute a large- 

 family, mainly characteristic of Asia, but also occurring in Europe, 

 Africa, Australia, and Polynesia. The supratemporal fossa is not 

 roofed over ; the dentition is acrodont ; and the premaxilke are 

 separate. Specimens referred to the type genus Agama have been 

 obtained from the Upper Eocene Phosphorites of Central France ; 

 while the Pleistocene of Australia has yielded a skull indistinguish- 



