268 TOWARDS THE HUMAN FORM 



the large American Lizards called Iguanas. They nourished in 

 the time of the Upper Cretaceous of England, Belgium, and 

 Germany. An early species, Iguanodon mantelli, was found in 

 England, and measured only five or six metres in length. The 

 complete skeletons of thirty individuals of another species, 

 Iguanodon bernissarti, were found together at Bernissart 

 between Mons and Tournay in Belgium, close to the French 

 frontier, at the bottom of a mine-shaft two hundred metres 

 below the present sea-level. They were discovered in an 

 excavation in the Carboniferous earths filled in by Wealden 

 clay, on the surface of which were still to be seen the imprints 

 of their feet, indicating that the hind-legs only were placed on 

 the ground. As no tracks made by the tail have ever been found, 

 it is to be assumed that it was held far above the ground and 

 was used to balance the Reptile. The Iguanodons were certainly 

 herbivorous ; they had no teeth in the fore-part of the mouth, 

 the lips probably being covered with a horny envelope. Their 

 attitude indicates, moreover, that they did not browse on grass, 

 but ate the leaves of trees, whose trunks they seized between 

 their powerful hands, as did Megatherium at a later date. 



The last representative of this group was Ornithomimns 

 of the Upper Cretaceous of Colorado, all four of whose limbs 

 were tridactyl, and in whom the proximal end of the third 

 metatarsal, set deep between the second and the fourth, was 

 partially united with them, as it is in young Birds. They were 

 very large animals, but unfortunately all we know of them is 

 their limbs. 



All the Dinosaurs that we have briefly passed in review were 

 marked by a family resemblance. They had a long neck, a 

 long tail, and a trunk generally not exceeding the neck in length. 

 The head was nearly always small, or even diminutive — so 

 much so that the brain was sometimes less in volume than the 

 lumbar portion of the spinal cord. They must have formed two 

 parallel series, the one carnivorous and the other herbivorous, 

 each beginning as a plantigrade species with a closed pelvis 

 and no post-pubis, and closing with an erect species having a 

 post-pubis. Having regard to the latest discoveries, this is 

 probably the order in which we shall have to set up their 

 genealogical classification. For if it be easy to understand that 

 animals feeding on the same kind of food should gradually 

 assume the series of attitudes just described,, it is hard to see 



