310 
Tl']liTli\IlY VEETEBEATA OF THE FATOM. 
a. ri(l<^e runs downwards and forwards to the base of the anterior zygapophyses (see 
n. XXVI. fig. 4 b). 4’liese processes, which may perhaps he described as enormously 
develo])ed anapojjliyses, are present, tliough of very small size, in some of the vertebnc 
of Palwophis. 'I’lie genus was founded by Lucas for the reception of the species 
F. schncherti, a large snake from the Eocene of Alabama, where it occurs associated 
witli remains of Zeuglodons. In the Eocene of Egypt, also, there is one species, 
likewise associated with the remains of Zeuglodon. 
Pterospherius scliweinfurtlii (Andrews). 
[Plate XXVI. figs. 4-G.] 
1001. Mo’riojdits schicehifniihi, C. AF. Andrews, Geol. Mag. [4] vol. viii. p. 438, fig. 2. 
Tf/pe Specimen. — A dorsal vertebra (PI. XXVI. fig. 4) ; Geological Museum, Cairo. 
This species is distinguished from P. schucherti by having the posterior face of the 
neural arch above the zygantriim considerably more expanded, so that the free portions 
of tlie })osteio-lateral processes are shorter. 
Form, cf Loc. — Qasr-cl-Sagha beds (Middle Eocene) : nortli of Birket-el-Qurun. 
The vertebrie of this species occur in great numbers scattered along the Middle 
Eocene escar]'»ment, but only in very rare cases are even two found united or so 
situated that they may be reasonably supposed to belong to the same animal. 
The procoelous centrum is considerably elongated, and is about as wide as it is 
high; the anterior cup is deep and nearly ci^’cular in outline, except beneath the 
neural canal, where its border is straight ; the posterior convexity is nearly hemi- 
spherical. On the ventral surface there is a strong median hypapophysial ridge [injp.], 
usually produced into two forwardly and downwardly directed processes, one situated 
close to the anterior end of the centrum, the other near the middle. The transverse 
processes {t.p.) are short and situated ventro-laterally on the anterior end of the 
centrum, below which they project considerably ; their outer ends bear the vertically 
elongated convex surfaces for the ribs, looking downwards and outwards. From the 
position of the rib-facets it appears that the body must have been laterally compressed 
to a considerable degree. Fiann the upper ends of the transverse processes a ridge 
runs upwards and forwards to the anterior angles of the ])rezygapophyses {a.z.), 
which project considerably in front of the centrum ; their oval articular facets are a 
little below the level of the floor of the neural canal, and look upwards aud a little 
backwards. 'Ihe articular surfaces of the zygos})liene (rs.) are almost jrarallel with 
those of the prezygapophyses ; they are borne on the ventral face of two prominent 
processes, the up])er edges of which unite to form the anterior border of the neural 
spine. The ])ostzygapophyses {p.z.) look dbwinvards and a little foiuvards, their 
surfaces being about on a level Avith the top of the centrum. The zygantrum [za.) 
