Mesozoic Reptilian Age. 89 



< < Unlike all other reptiles the Sacrum corresponded to five combined 

 vertebrae as in the higher mammals."* The haunch bone was prolonged 

 backward as in birds, the hind legs were much more developed than the 

 fore legs, and possessed only three fully developed toes, and the limb 

 bones were hollow like the bird's. ' ' It seems certain that all the 

 Dinosaurs walked with free steps like quadrupeds instead of crawling 

 like reptiles, and some, if not all of them, had the power of standing 

 and walking on their hin$ legs alone like birds. The backward elonga- 

 tion of the ischiatic bones seems evidently connected with the erection of 

 the body on the hind legs, "f The Iguanodon was an herbiverous 

 Dinosaur some 30 feet long with habits like a river horse. The Ceteo- 

 saur was also herbiverous 10 feet high when standing, and 60 feet long. 

 His thigh bone was 64 inches long and 9 thick. This is the largest 

 land animal ever discovered. There was another, very like a bird with 

 long tail, long hind legs upon which he habitually walked, long neck 

 and small head, with carniverous teeth. It is called the Compsognathus. 



The Pterosaurs were represented chiefly by the Pterodactyl. This 

 animal had a short body, and short spinal prolongation, large head with 

 sharp conical teeth in a long Saurian mouth. His hind limbs were 

 small, the fore limbs long and stout, with 5 digits on each. The outer 

 digit was immensely prolonged to sustain the large membranous wing, 

 as with the bat, leaving the other four free for grasping and clawing. 

 The bones were hollow. In size they run in different species from 2 to 

 20 feet from tip to tip of wings. They became extinct in the Cretaceous 

 period. 



Besides these bird-like Saurians the Jurassic period furnished the first 

 fossil bird with feathers but a very Saurian-like bird. It had a long 

 vertebrate tail containing twenty vertebrae, with a pair of long feathers 

 for each vertebra, and jaws with reptilian teeth. The hand had four 

 fingers all separate and two of them terminated with claws. This bird 

 was found in the Jurassic of Solenhofen. Its whole length was 18 

 inches of which the tail was half. It was named the Archeopteryx 

 Macrurus. Including the two or three specimens found in the Triassic, 

 the number of mammals discovered previous to the Cretaceous amounts 

 to about 20 species. They are all small marsupials and all insectiverous 

 except one. The opossum and kangaroo tribes, pouched rats, etc. , are 

 the modern marsupials. ( See tables. ) 



There is a considerable advance in insect life in the Jurassic and most 

 of the general orders are represented as follows : 



The Neuropters by the Dragon fly and Termes ( white ant ). The 

 Orthopters ( Locust family, ete. ) by the Blatta Acheta, etc. ; the Co- 

 leopters (Beetle tribes) by the Carabaeus, Buprestis, Coccinella, etc.; the 



* Dana 462. t Le Conte 431. 



