26 
THE EACES OF ALDABEA. 
Also the caudal plate is slightly bent outwards, with a rather concave surface. The 
high humps of the vertebral and costal scutes, which are so conspicuous in variety a, 
are here entirely absent ; but in all the scutes the smooth areolar portion can be clearly 
distinguished from the very broad striated portion, the striae being rather wide. The 
sternum is deeply concave, broad, with the anterior portion not conspicuously contracted, 
and with a shallow notch in front and behind, the substance of the caudal plates and 
of the lateral portion of the abdominals being thickened and callous. In the scutella- 
tion of the head and limbs this variety does not differ from variety a ; also the tail is 
nearly of the same length and provided with a flat terminal claw. 
The carapaces of the younger specimens agree in the essential particulars with the 
larger ; but they are decidedly higher, the surface of the costal plates being more ver- 
tical and the slope of the anterior vertebral scute less steep. 
The colour of the three specimens is black, with a horny tinge about the areolar 
portions. 
The measurements of these specimens are as follows: — 
Length of carapace. 
Width of carapace. 
Depth of 
Sternum. 
Caudal plate. 
In str. line. Over cm've. 
In str. line. Over curve. 
carapace. 
Length. 
Width. 
Length. 
Width. 
in. 
in. 
in. 
in. 
in. 
in. 
in. 
in. 
in. 
Ad. c? 
,,, 43 
501 
30 
50 
201 
31i 
26 
H 
9 
Ad. c? 
,.. 40 
52 
30 
52 
18i 
32 
24 
[?] 
10 
H.-gr. 
d 
... 31 
41 
19 
40 
17 
[?] 
18 
3 
7 
H.-gr. 
... 291 
38 
18 
40 
15 
23 
17 
2i 
7 
Osteology. — In the preceding remarks, as well as in the following notes on the osteo- 
logical characters of the various species, it is not my intention to give such a complete 
description as would include every detail common to all the species of Testudo, but 
I shall limit myself to those points only by which the various species of gigantic Tor- 
toises differ from one another in a marked manner. 
The sJcull, figured on Plates VIII. & IX. fig. A, measures in length from the occipital 
condyle to the extremity of the snout 5| inches, and from the extremity of the occi- 
pital crest to that of the snout 6|- inches ; its greatest width is 4^ inches. Large as 
this skull is, it is surpassed in size by that of specimen c, the corresponding measure- 
ments of which are 6, 6^, and 4^ inches. In the details of their structure and con- 
figuration these skulls are perfectly identical. They are distinguished from those of 
the other species by the very shallow excision of the hind margin of the paroccipital, 
and by their great relative breadth. 1*. The frontal region is raised and convex, 
broad, its greatest width (in front of the postfrontal) being one half of the distance of 
* In this and the following description of the skulls the same points are noticed under the same numbers — 
a plan by which the comparison of the several parts (sometimes described many pages apart) is much facilitated. 
The significance of certain modifications of structure noticed here will become more apparent when we shall 
treat of the skulls of the Mascarene and Galapagos Tortoises. 
