2 74 THE OSTEOLOGY OF THE REPTILES 



and seem to be as important in classification as those distinguishing 

 the much more typically lizard-like mosasaurs. 



No extinct lizards are certainly referable to this tribe, though it is 

 probable that some referred to it will eventually be found to have all 

 the essential characters of the group. 



Family Amphisbaenidae. With the characters of the group. 



Oligocene. Rhineura Cope, Aciprion Cope, Diacium Cope, Hy- 

 porhina Baur (a postorbital arch). Cremastosaurus Cope, Platyrha- 

 chis Cope, North America. 



Tribe Rhiptoglossa 



Small, arboreal, perching lizards. Arches complete, the quadrate 

 slender. Postfrontals indistinguishable; premaxillae small or vesti- 

 gia] ; no septomaxillae ; parietals and f rontals unpaired ; no parietal 

 foramen; epipterygoids absent or vestigial; palate with openings. 

 Vertebrae procoelous; five cervicals, from eleven to fifteen dorsals, 

 two sacrals, and slender, prehensile tail, the spines sometimes elon- 

 gated. Clavicles absent or vestigial. Mesopodials much reduced, 

 digital formula 2, 3, 4, 4, 3, the digits in opposable groups of two and 

 three. Abdominal ribs present. 



A group composed of about fifty living species confined to Mada- 

 gascar, Africa, and India. A curious group of insectivorous tree 

 Hzards, long famous for their power to change color, and for their 

 peculiar grasping digits. Our paleontological knowledge of them is 

 vague. 



Family Chameleontidae. With the characters of the group. 

 Eocene. Chameleo (Leidy), North America. Prochameleo de Ste- 

 fano, France. 



Genera Incertae Sedis 



Triassic. ? Paliguana Broom. South Africa. 



Jurassic. ? Saurillus Owen. Jura, England. 



Eocene. Enigmatosaurus Nopcsa (de Stefano), Europe. Nao- 

 cephalus Cope, North America. 



Upper Cretaceous. Coniosaurus Owen, Saurospondylus Seeley, 

 England. ? Tylosleus Cope, North America. , 



Pleistocene. Notiosaurus Owen, ? Patricosaurus Seeley, England. 



