Q IG ANTOPIIIS GAESTINI.— PTEIIOSPIIENUS, 
309 
AVidtli of articular ball of centrum 2'4 
Extreme length of centrum 4 
AVidth of neural canal 1‘7 
Height of rih-facets 1'8 app. 
The combined length of the four united vertebne figured on IM. XXVI. fig. 1 
is about 12'8 cm. 
R. 3188. Large and nearly complete vertebra, figured PI. XXVI. fig. 2. The dimensions (in 
centimetres) of this specimen are : — 
Greatest height from top of neural spine to end of hypapopliysis . 5-7 
„ width (between the ends of the transverse processes) . G’3 
AVidth between outer angles of posterior zygapophyses . . . 6-3 
„ „ upper angles of zygosphene 2-9 
„ of articular cup of centrum 2'3 
Height of articular cup of centrum 1'9 
AVidth of articular ball of centrum 2’3 
Extreme length of centrum 4 
AVddth of neural canal I’o 
Height of rib-facets 2'2 
C. 10210. A number of similar vertebrae. 
R. 3010. Three similar vertebrae. Presented by the Egyptian Government, 1903. 
C. 10023. Posterior portion of left ramus of a mandible, possibly belonging to this species. Figured 
on PI. XXVI. fig. 3. 
Family PALiEOPHID.F. 
Large snakes, probably of marine habits. Vertebrte with tall neural spines ; costal 
articulation placed low down on the centrum. litemal carina on centrum not 
unfrequently terminating on anterior and posterior processes. This family is probably 
nearly related to the Pythonidae. 
Genus PTEROSPHENUS, Lucas. 
[Proc. U.S. National Museum, vol. xxi. (1899) p. G37.] 
1901. Mceriophis, C. AV. Andrews, Geol. Mag. [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 
