96 EXTINCT MONSTERS. 



their command, it is wonderful that their forecasts should have 

 turned out so successful. Thus Professor Owen predicted for 

 the Iguanodon a total length of twenty-eight feet, and specimens 

 discovered of late years show a length of twenty-four feet. In 

 some, the thigh-bone exceeded a yard in length; this indicated 

 an animal of great size, since in the largest crocodiles this bone 

 is scarcely a foot long. Again, Dr. Mantell, from a study of the 

 imperfect jaw-bones in his collection, concluded that the lower 

 jaw was invested with a well-developed fleshy flexible lip, and 

 that the mouth was provided with a tongue of great mobility and 

 power. "There are strong reasons," he says, "for supposing 

 that the lip was flexible, and, in conjunction with the long fleshy 

 prehensile tongue, constituted the instrument for seizing and 

 cropping the leaves and branches, which, from the construction 

 of the molars, we may infer, constituted the chief food of the 

 Iguanodon. The mechanism of the maxillary organs (jaws), as 

 elucidated by recent discoveries, is thus in perfect harmony with 

 the remarkable characters which rendered the first known teeth 

 so enigmatical ; and in the Wealden herbivorous reptile we have 

 a solution of the problem, how the integrity of the type of 

 organisation peculiar to the class of cold-blooded vertebrata was 

 maintained, and yet adapted, by simple modifications, to fulfil 

 the conditions required by the economy of a gigantic terrestrial 

 reptile, destined to obtain support exclusively from vegetable 

 substances; in like manner, as the extinct colossal herbivorous 

 Edentata (sloths, see Chapter XII.), which flourished in South 

 America ages after the country of the Iguanodon and its in- 

 habitants had been swept away from the face of the earth." 



Dr. Mantell also was the first to prove, from the nature of the 

 Wealden strata, that they were deposited in or near the estuary 

 of a mighty river. With regard to the aspect of the country in 

 which the Iguanodon flourished, he showed that coniferous trees 

 probably clothed its Alpine regions; palms and arborescent 

 ferns, and cycadaceous plants (i.e. plants resembling the modern 



