70 COPE 



The Orthopoda includes the Scelidosauridse, Hypsirho- 

 phidse, Agathaumidse, Camptosauridse, Iguanodontidse and 

 Hadrosauridse, all supposed to have been of herbivorous 

 habits. Representatives of these families have been found 

 in both Europe and North America, excepting the Scelido- 

 sauridse, the members of which are so far only known 

 from Europe. They all include large forms, but the 

 most gigantic are members of the last four families. 

 These had an additional bone, the predental, which formed 

 a toothless extremity of the lower jaw, while the Aga- 

 thaumidee had a corresponding toothless bone in front 

 formed of the premaxillary. In all the families ex- 

 cept the Agathaumidse the successional teeth appear on 

 the inner side of the base of the functional teeth, as in 

 lizards. In the Agathaumidse they appeared under the 

 middle of the base, as in crocodiles. In all except Hadro- 

 sauridse one row was in functional use at a time ; but in the 

 Hadrosauridse two or three rows were used at once. Some 

 of the species of the latter had as many as 2,000 teeth ar- 

 ranged in four magazines, one in each jaw (Fig. 23). The 

 Agathaumidse mostly had formidable horns on the head, at 

 the middle of the nose and over the eyes. Agaihaumas 

 sylvesfre Cope reached a length of forty feet, and had the 

 legs of sub-equal length. Many of the Hadrosauridse were 

 of kangaroo-like proportions. 



The Dinosauria include the great land reptiles of the 

 Mesozoic system. The order embraces no species adapted 

 for flight, and none adapted for a life in which movement 

 was made by paddles or limbs modified for swimming. 

 The order includes the largest land animals that have ever 

 lived, and their remains have been found in all continents 

 except the Australian. 



