50 



Sauropterygia Plesiosauridce. 



Wall-case, 

 No. 13. 



like the flippers of a whale, and made up of 5 fingers, com- 

 posed of numerous phalanges. The jaws were armed with many 

 Table-cases, simple pointed teeth inserted in distinct sockets. The most 

 ' ' ' complete examples are the Plesiosaurus Hawkinsi, the PL 



FIG. 66. A tooth of Polyptychodon 

 mterruptus (Owen); Greensand. Cam- 

 bridge. 



FIG. 67. An upper tooth of 

 Peloneustes philarchus (Seeley) ; 

 Oxford Clay, Bedford, i. 



FIG. 68. Plesiosaurus Hawkinsi (Owen). Anterior and left lateral aspect of a late 

 cervical vertebra, from the Lower Lias of Lyme Begis, Dorset; co, costal facet; 

 prz, prezygapophysis ; ptz, postzygapophysia. 



