SAUEOPTERYGIA 223 



appears to have been suturally united to the centrum with 

 large zygapopkyses. The articular end of the centrum is 

 vertical to its axis ; both are slightly concave. Between each 

 centrum is a transversely oval, depressed ossicle, homologous 

 with the cervical wedge-bones or hypapophyses in Enaliosaurs. 

 This is the chief peculiarity in S r phenosaurus, and recalls a 

 character in the vertebral column of Arclwgosaurus. 



Genus Plesiosaurus. — The discovery of this genus forms 

 one of the most important additions that geology has made to 

 comparative anatomy. Baron Cuvier deemed the structure of 

 the Plesiosaur " to have been the most singular, and its cha- 

 racters the most anomalous that had been discovered amid the 

 ruins of a former world." " 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 proportions of 

 an ordinary quadruped, the ribs of a chameleon, and the paddles 

 of a whale" (fig. 71). "Such," writes Dr. Buckland, "are the 

 strange combinations of form and structure in the Plesiosaurus, 

 a genus, the remains of which, after interment for thousands 

 of years amidst the wreck of millions of extinct inhabitants of 

 the ancient earth, are at length recalled to light by the re- 

 searches of the geologist, and submitted to our examination, 

 in nearly as perfect a state as the bones of species that are 

 now existing upon the earth." 



The first remains of this animal were discovered in the 

 Has of Lyme Eegis about the year 1822, and formed the subject 

 of the paper by the Eev. Mr. Conybeare (afterwards dean of 

 Llandaff), and Mr. (afterwards Sir Henry) De la Beche, in 

 which the genus was established, and named Plesiosaurus 

 (" approximate to the Saurians "), from the Greek words 2^esios 

 and sauros, signifying " near " or " allied to," and " lizard," 

 because the authors saw that it was more nearly allied to the 

 lizard than was the Icldh/osaurus from the same formation. 



The entire and undisturbed skeletons of several individuals, 



