ROOM III. PLESIOSAURUS. 341 



fractured bones and waterworn relics of the terrestrial reptiles 

 whose remains formed the subject of the previous section of 

 this chapter. The beautiful state of preservation of many of 

 the Plesiosauri, the entire skeleton, from the point of the 

 muzzle to the extremity of the tail, lying in relief, as if it had 

 sunk down quietly on the soft clay, and become petrified on 

 the spot, manifests how different were the conditions in which 

 the strata of the Lias and the Wealden were deposited ; while 

 the exquisite manner in which the investing stone has been 

 removed, attests the consummate skill and indefatigable zeal of 

 the gentleman by whom these superb fossils were developed. 1 



I shall reserve for the next chapter an account of the 

 circumstances under which the matchless series of Enalio- 

 saurian remains in our National Museum were obtained ; and 

 restrict my remarks to the description of the individual speci- 

 mens in the Wall-cases D, E, and F, of this Room ; those 

 in Case D are arranged as under : 



WALL-CASE D. [4.] 



Original specimen of Plesiosaurus dolichodeirus. I 



(Rev. W. D. Conybeare, " Geol. Trans." vol. i. PI. XVIII. | 2Op " 



Plesiosaurus Hawkinsii. PL XXIV. of Mr. Hawkins's work. 



Bones of the 



Plesiosaurus 



arcuatus. 



Plesiosaurus dolichodeirus : 



the under surface of lower jaw exposed, 



and two paddles on the right side. 



Bones of the 



Plesiosaurus 



arcuatus. 



PLESIOSAURUS. The animals of this genus present in their 

 osteological structure a remarkable deviation from all known 

 recent and fossil reptiles ; uniting the characters of the head 

 of a lizard, with the teeth of a crocodile, to a neck of inordi- 

 nate length, and with such modifications of the ribs, the 

 pectoral and pelvic arches, and the paddles, as to justify the 

 graphic simile of an eloquent Professor, that the Plesiosaurus 

 might be compared to a serpent threaded through the shell of 

 a turtle. 



The character which immediately strikes the observer, is 



1 Thomas Hawkins, Esq. The splendid volume of this gentleman on 

 these marine saurians cannot fail to delight the reader by its graphic 

 descriptions, and beautiful illustrations. See APPENDIX K, Mr. Haw- 

 kins's Collection of Enaliosauria. 



