466 LOWER VERTEBRATES. 



generic portion of the scientific name, Amphicoelias akitiis. Tlie fcimir of this ani- 

 mal, tliough exceeding in lengtli tliat of the Camarasaurus, was mucli more slender and 

 probably supported a less bulimy animal, though one that probably had a greater 

 height. It is estimated that A. alatus could reach to the tops of trees thirty feet higli. 

 But huge saurians did not stop with the discovery of this species, for soon there was 

 brought to light the fragments of an animal, one of whose dorsal vertebra? measured six 

 feet from the base of centrum to tip of sjjine, and, if of similar proportions to its con- 

 gener, its femur nuist have measured twelve feet, and the whole animal may liave ex- 

 ceeded the length of one hundred feet. This species has been named A. fragiUimus, 

 and possibly walked along the rocky shores, submerged in the water, and feeding on 

 alg£e or other vegetable matter. 



The figure illustrating the skeleton of Urontosaurus was made from a single indi- 

 vidual of about fifty feet in length, and beautifully illustrates the peculiarities of 

 structure presented by members of this group. The head, it will be seen, docs not 

 exceed in size some of the bones of the neck, and the brain cavity is of the smallest 

 dimensions, indicating an animal of stupid habits. Such a reptile may have splashed 

 round in the water in search of marine vegetable growths, each time it placed one of 



Fig. 269. — Brontosaurus. 



its feet down making a depression a yard square and of considerable depth, as an 

 animal was su]iported which weighed twenty tons or more, a weight so great that the 

 reptile was not infrequently mired. In its habits it was slow, and probably intimi- 

 dated what few enemies it might have had by mere size alone, as there have been found 

 no offensive organs nor defensive armor. When walking on shore it might occasion- 

 ally have elevated itself on its haunches, and, propped up by its tail, reached into the 

 tops of the trees and browsed on the leaves and small branches. In this upright posi- 

 tion, however, it is not likely that the animal could progress for any great distance. 



We now come to the group of Dinosaurian reptiles which had the tarsal bones 

 united with the tibia and at an angle, effectually preventing the foot from being ex- 

 tended in a line with the leg, a peculiarity of structure presented also by the young 

 chick. The most interesting genus is Lcdaj^x, some of the representatives of which 

 stood eighteen feet in height and were carnivorous animals of the most rapacious 

 habits. They undoubtedly kept within projier limits animals which might otherwise 

 have unduly increased in numbers. The structure of the bones of the hind Ihnb 

 show Lailaps to have been a plantigrade biped, while the massive tail gives reason for 

 believing that, when at rest, a jiosition was taken not unlike that maintained by the 

 kangaroo. The jaws were of considerable size and armed with shai-p lance-like teeth, 



