202 MARINE SAURIANS. 
sand, or more than ten times ten thousand years 
ago, all these vast intervals seem annihilated, 
time altogether disappears, and we are almost 
brought into as immediate contact with events 
of immeasurably distant periods, as with the 
affairs of yesterday. 
SECTION VI. 
PLESIOSAURUS.* 
We come next to consider a genus of extinct 
animals, nearly allied in structure to the Ichthy- 
osaurus, and co-extensive with it through the 
middle ages of our terrestrial history. The dis- 
covery of this genus forms one of the most im- 
portant additions that Geology has made to com- 
parative anatomy. It is of the Plesiosaurus, that 
Cuvier asserts the structure to have been the 
most heteroclite, and its characters altogether 
the most monstrous, that have been yet found 
amid the ruins of a former world. t To the head 
of a Lizard, it united the teeth of a Crocodile ; 
a neck of enormous length, resembling the body 
of a Serpent : a trunk and tail having the pro- 
portions of an ordinary quadruped, the ribs of a 
* See PI. 16, 17, 18, 19. 
t Get habitant de Tancien monde est peut-etre la plus hetero- 
clite et celui de tous qui paroit le plus meriter le nom de monstre. 
— Oss. Foss. V. Pt. 2, p. 476. 
