270 
DE. A. GUNTHEE ON GIGANTIC LAND-TOETOISES. 
examples of the same size of T. ephippium by the greater relative width of the carapace. 
The principal measurements of the specimens, described, are as follows : — 
Length of carapace. Width of carapace. Sternum. Caudal plate. . 
In str. Line. 
Over curv. 
In str. line. 
Over curv. 
Length. 
Width. 
Length. 
Width. 
Spec. no. 
inches. 
inches. 
inches. 
inches. 
inches. 
inches. 
inches. 
inches. 
1. (J 
. . . 41 
52 
33 
53 
51 
7 
2. 6 
. . '. 22 
27 
16 
27 
181 
15f 
3 
4 
3. . 
. . . 151 
191 
11 
19 
12 
91 
21 
If 
4. . 
00 
101 
6 
101 
61 
6 
11 
1 
The skull (Plates 37-39. fig. D) is distinguished by its comparatively longer facial 
portion, and by the much produced mastoid processes ; it is (see also Geay, Catal. 
Tort. 1855, 4to, tab. 34) 51 inches long, measured from the intermaxillary to the occi- 
pital condyle, and 41 inches broad at its widest part, viz. between the tympanic pro- 
cesses. 1. Its frontal region is flat, narrow, its greatest width being two sevenths of 
the distance of the tympanic condyles. 2. Only the foremost part of the parietals 
forms a flat surface, the remainder being compressed into an almost trenchant crest, 
passing into the long narrow occipital spine, which is scarcely raised above the level of 
the skull (Plate 38. fig. D). 3. The tympanic case with the mastoid is produced far 
backwards, so that the paroccipital margin appears as a deep semicircular excision 
(Plates 38 & 39. fig. D, a). 4. A very deep hollow on the lower surface of the 
occipital, in front of the condyle ( b )*. 5. On the front margin of the temporal fossa, 
corresponding to the suture between parietal and tympanic, immediately in front of the 
foramen carotidis extern®, there is a large, prominent, flat, rough tuberosity (c) for the 
insertion of a portion of the temporal muscle ; a broad, not very deep groove (d) sepa- 
rates this tuberosity from the zygomatic arch. 6. Tympanic cavity exceedingly large, 
especially its posterior portion, the entrance being somewhat narrowed by the groove 
just mentioned; the outer tympanic rim is a regular circle, with a shallow notch in its 
hinder circumference for the passage of the Eustachian tube. 7. This notch is very 
remote from the columellar foramen, and a sharp ridge runs the whole distance from 
the notch to the foramen, serving as a rest for the auditory ossicle. 8. The posterior 
wall of the inner tympanic cavity, which in fresh examples is formed by cartilage and 
an open space in the preserved skull, is of but small extent, only about one eighth of 
the tympanic opening. 9. The front margin of the intermaxillaries projects beyond 
that of the frontals, but much less so than in the Mascarene Tortoises, so that the nasal 
opening, although still obliquely sloping downwards, is scarcely higher than broad. 
10. The inner nostrils are advanced, not very distant from the end of the snout, and on 
the palatal view of the skull are nearly entirely hidden below the alveolar lamella of 
the maxillaries. 11. The intermaxillaries are short, not quite one half of the length 
of the maxillaries, and their foremost portion is deeply hollowed out below, and verti- 
* In the figure given by Dr. Gray the artist has entirely omitted to express the depth of this hollow by 
shading. 
