REPTILIA. 41 



sic, culminated in the Jurassic, and continued in diminishing 

 numbers to the end of tlie Cretaceous period, wlien tliey became 

 extinct. 



The Dinosaurs were all terrestrial, mostly of lai-ge size, and 

 tlie probable progenitors of the birds. In the conformation of 

 the pelvis and hind limbs they were much like the ostriches. In 

 many species the fore limbs were so small proportionately as to 

 be of little use in locomotion. These creatures, walking upon 

 their hind legs alone, produced the bird-like tracks so abundant 

 in the Triassic brownstone of Connecticut and New Jersey. 



The order includes both carnivores, like Lcelajys of America, 

 and Megalosaurus of Europe, and herbivores, as Iguanodon of 

 Europe, and Iladrosaurus, Brontosaitrus^ Stegasaurus and At- 

 lantosaurus of this country. The latter is the largest yet dis- 

 covered. It was at least fifty or sixty feet long and thirty feet 

 high, when erect. The huge, bulky, herbivorous monsters were 

 probably kept in subjection by the more active, ferocious, well- 

 armed and possibly warm-blooded carnivores. 



No. 58. [200] Iguanodon Mantelli, Meyer. 



Lower Jaw (cast). This great Dino- 

 saiirian was brought to light by Dr. 

 Mantell, in 1834. It was an oviparous, 

 herbivorous, terrestrial quadruped, "a 

 crocodile lizard of the dry land." With 

 other huge Dinosaurs, it occupied in 

 the Reptilian Age the same relative 

 station in the scale of being, and fulfilled the same general purposes in the 

 economy of nature as the Mastodons, Mammoths and Megatheriods of the 

 Pleistocene Period, and the existing gigantic Ungulates and Proboscidians. 

 Fragments of coniferous trees, aborescent ferns -and cycadeous plants have 

 been found with its remains, showing the nature of its food. Prof. Owen 

 estimates the length of the head at three feet, of the trunk at twelve feet, and 

 of the tail at thirteen feet. Some individuals were much larger. An almost 

 complete skeleton (one of a number found a few years since in the Wealden 

 of Belgium), has been put together in the Brussels Museum, showing.a length 

 of over 30 feet. It is supposed to have been aquatic in habit. The known 

 species are all European. This almost perfect specimen of the lower jaw is 

 interesting, showing as it does that in the small extent of the symphysis the 

 Iguanodon resembles the Lizards, and differs from the Crocodiles, while in the 

 position of the symphysis and its sloping edentulous character the Iguanodon 

 differs from all modern Reptiles. It was found in the Wealden strata, Sussex, 

 England, and belongs to the British Museum. Size, 20 x 11. 



No. 59. [204] Iguanodon Mantelli, Meyer. 



Tooth (cast). The teeth of the Iguanodon differ in structure from those of 

 every other known Reptile, but somewhat resemble in form those of the living 



