GIGANTOPHIS GAESTINI.— PTEROSPHENUS. 



309 



Width of articular ball of centrum 2--t 



Extreme length of centrum 4 



Width of neural canal 1'' 



Height of rib-facets I'S app. 



The combined length of the four united vertebrae figured on PL XXVI. fig. 1 

 is about 12'8 cm. 



E. 3188. Large and nearly complete vertebra, figured PI. XXVI. fig. 2. The dimensions (in 

 centimetres) o£ this specimen are : — 



Greatest height from top of neural spine to end of hypapophysis . 5-7 



,, width (between the ends of the transverse processes) . 6'3 



Width between outer angles of posterior zygapophyses . . . 6-3 



,, „ upper angles of zygosphene 29 



„ of articular cup of centrum 2-3 



Height of articular cup of centrum 1-9 



Width of articular ball of centrum 2-3 



Extreme length of centrum 4 



Width of neural canal 1'5 



Height of rib-facets 2-2 



C. 10210. A number of similar vertebrae. 



K. 3010. Three similar vertebrae. Presented by the Egyptian Governnwnt, 1903. 



C. 10023. Posterior portion of left ramus of a ma:idible, possibly belonging to this species. Figured 

 on PI. XXVI. fig. 3. 



Family PAL^OPHID^. 



Large snakes, probably of marine habits. Vertebrae with tall neural spines ; costal 

 articulation placed low down on the centrum. Haemal carina on centrum not 

 unfrequently terminating on anterior and posterior processes. This family is probably 

 • nearly related to the Pythonidse. 



Genus PTEROSPHENUS, Lucas. 



[Proc. U.S. National Museum, vol. xxi. (1899) p. 637. J 



1901. MceriopUs, C. W. Andrews, Geol. Mug. [4] vol. viii. p. 438. 



The snakes belonging to this genus are distinguished from other members of the 

 family by the presence on the posterior end of the arch above the zygantrum of a pair 

 of strong pointed processes directed upwards and backwards. On their anterior face 



