1^88 
TEKTIAET VEETEBEATA OE THE FAYtM. 
it is at once distinguished by tlic circumstance that the o])isthotic and the squamosal 
join as usual, and there is a distinct epipterygoid, indicating that this Turtle is a 
member of the Chelonidrc. The occipital condyle is trilobate and the basioccipital 
portion thrusts itself between the exoccipital lobes, reaching the foramen magnum. 
In front of the occipital condyle the ventral face of the basioccipital is compara- 
tively hat, and there is no deep depression at its union with the basispheiioid as in 
Chelone; laterally, together with the exoccipitals, the basioccipital forms a flat vertical 
surface, which is larger than is found in either Chelone or Thalassochelys. The 
opisthotics (o.o.) are arranged as in the recent types and are firmly united at 
their outer ends with the squamosals [sq.) ; they form the upper border of a large 
fossa into which several foramina opened. The form of the tympanic cavity {t.o.) 
is almost as in Chelone \ it seems, however, to be a little more sharply defined 
in front and a little more elongated in a vertical direction. Tlie pedicle of the 
(piadrate (jq.) is longer than in the recent forms, so that the articular surface for 
the mandible is further below the level of the palate. 
The basispheiioid bears a pair of ridges, which converge forwards meeting in the 
middle line ; on its u]iper (cranial) surface there is a strong median ridge. The 
opi])terygoids arise by a narrow base and are less flattened from within outwards than 
in Chelone or Thalassochelys caretta. 
There is no doubt that the skull here described is that of a member of the 
Chelonidit', and since in the form of its basioccipital and basispheiioid it resembles 
the skull of Thalassochelys rather than that of Chelone, it is referred to that genus ; 
but further material in better preservation is required before its precise position can 
be made out. 
C. 10029. Posterior portion of skull, uncrushed but much covered with a reddish inatri.x: and 
apparently impregnated with salt. The type described in Geol. Mag. [4] vol. viii. p. 441. 
Figured PI. XXV. fig. 4. The dimensions (in centimetres) of this specimen are: — 
lleiglit of skull (from basis])henoid to roof) 7’5 
(Greatest width at squamosals 15'4 
Width between outer angles of the quadrates 
,, of occipital condyle 2‘4 
C. 10030. Much cru.shed and weathered skull, inconqdete in front, showing the roofed-in temporal 
fossm. 
R. 3192. A similar but rather more imperfect siiecimen. 
r resented hii the E<jijptian Goreriunent, 1904. 
