THE EMPIRE OF THE GREAT REPTILES. 169 



Another remarkable group is that to which Cope has given 

 the name of ryihi)no7norpha, and which he regards as allied 

 to the serpents, or as gigantic sea-serpents jjrovided with 

 swimming paddles, but which Owen considers more nearly 

 connected with the lizards. In either case they constitute a 

 group by themselves, remarkable not only on account of their 

 anatomical affinities with animals so unlike them in general 

 port, but also for their enormously extended length and formid- 

 able dentition (Fig. 143). Such animals as the Mososanrus 

 of Maestricht and Clidastes of Western America may have 

 exceeded in length the largest Ichthyosaurs and the most 

 bulky of living Cetaceans, though their slender forms and 

 numerous vertebrae remind one of the semi-fabulous sea- 

 serpent, rather than of any known animal of any geological 

 age. They were characteristic of the Later Mesozoic, more 

 especially of the Cretaceous period, and must have been 

 formidable enemies to the fishes of their time. 



Owen has formed two orders ^ for the rece])tion of some 

 remarkable extinct reptiles of this age, found especially in 

 South Africa and India, but also in Europe and America. 

 The first includes large lizard-like animals having horny jaws 

 like those of turtles, and in some of the species with great 

 defensive tusks (Fig. 144). Their mode of life is not well 

 known, but they may have been peaceable and harmless vege- 

 table feeders. The second has been already referred to, in 

 connection with the Permian, where it first appears, though it 

 is continued in the Trias (Fig. 145). The resemblance of 

 the skulls of these creatures to those of Carnivorous mammals 

 is very striking, and nothing can be more singular than their 

 early appearance and their decadence before the advent of 

 those Tertiary mc mials which in more modern times occupy 

 their place. 



Perhaps the most extraordinary of all the Mesozoic modifi- 

 cations of the reptilian type was that of the Hying reptiles, or 



^ Anomodontia and Thcriodontia. 



