SAUROPTERYGIA. 243 



.Sp. SpJienosaurus Sternbergii, Von. M. — The fossil vertebrae 

 on which this genus is founded are imbedded in a sandstone, 

 most like the bunter, from Bohemia or the south of Germany. 

 Of the twenty-three vertebrae so preserved in nearly their 

 natural position, and with their under surface exposed, five 

 belong to the tail, the rest to the trunk. Of these, two are 

 sacral, two lumbar, the rest are dorsal or thoracic, with long 

 and slender ribs connected with them. The neural arch 

 appears to have been suturally united to the centrum with 

 large zygapophyses. 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 Splienosaurus, and recalls a 

 character in the vertebral column of Archegosaurits. 



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. 93). " 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 researches 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 

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



