346 FOSSIL REPTILES. 



In a memoir inserted, in 1821, in the Transactions of the 

 Geological Society, they published their grand discovery of a 

 new genus of the same tribe, but more approaching to the 

 common lizards, which they named plesiosaurus. They have 

 there described the composition of the lower jaw of the ichthyo- 

 saurus, that of the muzzle, and a considerable part of that of 

 the posterior and inferior faces of the cranium. They showed 

 that the ring of osseous pieces in the sclerotic is a character of 

 lizard, and not of fish, and entered into new details on the ver- 

 tebrae and articulation of the ribs. 



A second memoir, by the same gentlemen, in the Geological 

 Transactions for 1823, while it extended the description of the 

 plesiosaurus, served to determine the notions concerning the 

 teeth of the ichthyosaurus, clearly expressed the characters of 

 its species, re-established the truth relative to the position of 

 its nostrils, and marked the relations and differences of struc- 

 ture between its head and that of the lizards. 



With materials so abundant, and given with so much care 

 and accuracy, it was possible to compose an osteological de- 

 scription of the ichthyosaurus at least as complete as that of 

 any lost animal. But M. Cuvier came to the task with addi- 

 tional advantages. Many drawings were sent to him by dif- 

 ferent lovers of science. From Mr. Cumberland, of Bristol, 

 he received a sketch of an entire skeleton, four feet ten inches 

 in length, found in 1818, near the sea, at Watchet, in Somer- 

 setshire, and belonging to Mr. Morgan, of Bristol : that of a 

 head, and teeth of several species, from the collection of Mr. 

 Johnson, of Bristol : that of many pieces, and among others^ 

 of an eye, found at Weston, near Bath, and preserved by Mr. 

 P. Hawker. He also had the good fortune to acquire certain 

 valuable pieces which supplied him with the means of furnishing 

 some additional characters to those which had been recognized 

 by his predecessors. It remained for him to show the forms 

 of the frontal and its accessory bones, the foramen of the parietal, 

 like that of lizards, and the sphenoid also much more like that 



