DR. A. GUNTHER ON GIGANTIC LAND-TORTOISES. 
273 
and basisphenoid simply shelving downwards towards the latter (b). 5. On the front 
margin of the temporal fossa, in front of the foramen caroticlis externae , there is a large 
not very prominent tuberosity ( c ) for the insertion of a portion of the temporal muscle ; 
no groove separates this tuberosity from the zygomatic arch ; or, in other words, the 
tympanic cavity is not constricted in front. 6. Tympanic cavity very large : the outer 
tympanic rim ovate, resembling the outline of the human concha, with the convex side 
in front, and the pointed part above ; the notch for the passage of the Eustachian tube 
is very broad, but shallow ( e ). 7. The ridge which runs from this notch to the stapedial 
foramen, and to which the columella is attached, is rather low and obtuse. 8-11. The 
points noticed under these figures in the description of the skull of T. elephant op us 
(see page 263) are exactly the same in the present species. 12. The palatal region is 
very shallow and broad, in consequence of the outer pterygoid edge being flattened 
down and expanded in its whole length (Plate 39. fig. C ,f). The triangular space, of 
which the foramina palatina and the anterior extremity of the vomer form the points, is 
isoscelous in shape, in accordance with the generally short longitudinal axis of the skull. 
13. Anterior surface of the tympanic pedicle with a shallow impression. 14. Lower 
jaw with a double alveolar ridge ; its symphyseal portion simply vertical, without a 
backward expansion of the lower margin of the bone. The parts of the angular and 
coronoid which face each other leave a rather wide cleft between them. Upper 
margin of the angular not excised. 
Limb-bones. — The following bones have been preserved in our large stuffed example, 
and were extracted from it : — The humerus (Plate 42. figs. B, B'), distinguished by its 
great length and slenderness ; its shaft is trihedral in the middle, and not much bent. 
The two hollows which we noticed in T. elephantopus below the head and above the 
trochlea are here absent. The ulnar tuberosity ( a ) projects high above the head, which 
is nearly entirely raised above the level of the summit of the radial tuberosity. The 
canal ( b ) for the blood-vessels on the radial edge, close to the elbow-joint, is deep and 
partly open, cutting off, as it were, a splint from the radial extremity of the bone. 
T. elephantopus , 
790 mUlims. long. 
miUims. 
Length of the humerus, measured in a straight line) 
from the summit of the head to the middle of l 216 
trochlea J 
Circumference of the narrowest part of the shaft . 89 
Longest diameter of the head 40 
Shortest diameter of the head 37 
Extreme breadth between the condyles .... 82 
T. epliippium , 
840 millims. long, 
millims. 
235 
91 
40 
35 
82 
The bones of the forearm (Plate 45. fig. B) are, like the humerus, comparatively 
slender ; they are remarkably smooth, without prominent ridges or tuberosities. The 
ulna has its radial edge but slightly emarginate, and is twisted round its longitudinal 
