LIFE IN THE MESOZOIC EPOCH 



469 



Sea- Serpents (Pythonomorphd). During the later part of 

 the epoch the marine reptiles belonging to the last two orders 

 diminished in numbers and importance. They were to some 

 extent replaced by the snake-shaped creatures of the present 

 group, with small short paddles. Some of the largest forms 

 (Mosasaurus] seem to have been 

 as much as 49 feet in length. 



Terrible Reptiles or Dinosaurs 

 (Dinosauria\ The members of 

 this varied group were the domi- 

 nant land-reptiles of the epoch, 

 and were represented by a great 

 variety of remarkable species. 

 The Reptile- Footed Dinosaurs 

 ( Sauropoda ) were herbivorous 

 forms with hoof-bearing planti- 

 grade extremities. Some of them 

 attained a very large size, the 

 most gigantic (Atlantosaurus) is 

 even believed to have been as 

 much as 115 feet long. The 

 Beast-footed Dinosaurs (Thero- 

 poda) were of carnivorous habit, 

 and distinguished by the great 

 proportionate length of their 

 hind-limbs, which suggests that 

 hopping was their typical mode 

 of locomotion. They included 

 species of greatly differing size, 

 from that of a cat to that of an 

 elephant. The Armoured Dino- 

 saurs (Stegosauria) were herbiv- 

 orous creatures, and in the type- 

 genus (Stegosaurus, fig. 1328), 

 which included species some 28 feet long, the back was pro- 

 tected by a series of large flattened bony plates, passing into 

 spines on the upper side of the tail. The head was of relatively 

 small size, and the brain so tiny that the intelligence must have 

 been small. The herbivorous Bird -Footed Dinosaurs (Orni- 

 thopodd) are so-called because the structure of their hind-limbs 



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