488 MESOZOIC ERA— AGE OF REPTILES. 



and the short, strong, well-fingered paddles of a whale, with the essen- 

 tial characters of a lizard. Another snake-like character possessed by 

 this order was rows of teeth on the palatal bones, in addition to those 

 in the jaws ; and a peculiar joint in the lower jaws, by means of which, 

 when aided by the recurved teeth, the jaws could act separately like 

 arms, in dragging down their throats prey which was too large to swal- 

 low directly (Fig. 818). 



Fig. 818. — Jaw of an Edestosaurus (Clidastes), x J (after Cope). 



We give on page 486 a restoration by Cope of one of the most 

 slender forms — Edestosaurus — and also, on page 487, head and tooth, 

 and limbs, of other Mosasaurs. 



The number of species are yearly increasing by new discoveries. 

 The remains of at least fourteen hundred individuals of Mosasauroids 

 alone are now gathered in Marsh's collection. 



According to Cope, 147 species of reptiles have been described from 

 the Cretaceous of North America, of which fifty are Mosasaurs, forty- 

 eight Testudinata (turtles and tortoises), eighteen Dinosaurs, fourteen 

 Crocodilians, thirteen Sauropterygia (Plesiosaur-like), and four Ptero- 

 saurs. At least three more Pterosaurs have been found, making the 

 whole number seven (Marsh). 



In Europe, Iguanodons, Teleosaurs, Ichthyosaurs, Plesiosaurs, and 

 Pterosaurs still continue in the Cretaceous, some of the last being 

 twenty-five feet in expanse of wing ; and also a few Mosasaurs were 

 introduced. 



Birds. — The history of the discovery of the earlier fossil birds is 

 instructive. Until 1858, with the exception of the doubtful tracks in 

 the Connecticut River sandstone, no birds had been found lower than 

 the Tertiary. In that year the bones of a bird, probably related to the 

 gull, were found in the upper greensand of England. In 1862 the won- 

 derful reptilian bird Archceopteryx macroura, already described (p. 444), 

 was found in the Solenhofen limestone of Germany (Upper Jurassic). 

 In 1870, and subsequently, Marsh discovered in the Cretaceous of New 

 Jersey and Kansas about twenty species of birds. Those from New Jer- 

 sey were from the Upper Cretaceous (Eoxhill group), and are probably 

 true birds — waders and swimmers — though not of the higher orders. 

 Those from Kansas are from a lower horizon (Colorado group — see table 

 on p. 474), and are all wonderful, toothed birds, entirely different from 

 any existing order. With the exception of the Archseopteryx, these 

 are the most extraordinary birds yet discovered. Some of them, be- 



