34 
THE EACES OF ALDABEA. 
suture, which is evidently accidental in this individual. However, it is singular that 
also Dumeril and Bibron describe this plate as divided. The sternum (Plate IV. fig. B) 
is deeply concave, broad, with the anterior portion somewhat contracted, truncated in 
front and behind, the substance of the caudal plates and of the lateral portion of the 
abdominals being much thickened and very callous. The scutellation of the head and 
legs does not differ from that of the other Aldabra species, the upper part of the snout 
being protected by the same large plates, and a longitudinal series of large scutes 
running along the outer edge of the forearm. The tail is long (about 9 inches), ter- 
minating in a long, strong, and flat claw. Dumeril and Bibron describe the tail of the 
skeleton in the Paris Museum as " inonguiculee." The colour is a uniform deep black. 
The younger specimen difiers in some respects, particularly as regards the form of the 
carapace ; but the sculpture of its scutes is exactly such as we should expect in an im- 
mature individual of this species, and the reversion of the anterior and posterior mar- 
ginals is already distinctly indicated. The upper profile, commencing from a pro- 
tuberance near the hind margin of the first vertebral plate and continued to the 
extremity of the caudal, is convex ; that between that tuberosity and the nuchal plate 
gently slopes downwards towards the latter. The whole carapace is of a regularly 
elliptical form, not broader behind than in front, and rather deep. The anterior as 
well as the posterior margins are indistinctly scalloped ; all the upper plates consist of 
a perfectly smooth areolar portion, which is not much smaller than the scute itself, the 
striated marginal portion being very narrow, with the strife shallow and broad. Nuchal 
plate, as in the adult specimen, large, broader than long ; caudal without any division. 
Sternum slightly concave, with a very shallow notch in front and behind. Tail with a 
well-developed terminal claw. Colour less deep black than in the adult specimen. 
The measurements of these two specimens are the following : — 
Lengtli of carapace. Widtli of carapace. Depth of Sternum. Caudal plate. 
In str. line. Over curve. In str. line. Over curve. carapace. Length. Width. Length. Width. 
Specimen, in. in. in. in. in. in. in. in. in. 
Ad.c?. 40 19 38 16 23 17^ 4 7 
Yg.cJ. 23 29 14i 28 lOJ 18 12^ If 5 
The skidl * of the larger of these examples measures in length from the occipital 
condyle to the extremity of the snout 4^ inches, or from the extremity of the occipital 
crest to that of the snout 5 inches, its greatest width being 3f inches. It is very 
similar to that of T. elephantina, but differs from it in the following points : — 3. The 
tympanic case, wdth the mastoid, is much produced backwards, the hind margin of the 
paroccipital forming a strong curve. 5. The tuberosity on the front margin of the 
temporal fossa is distinctly indicated. 6. The tympanic cavity is large and deep, the 
outer tympanic rim having a subsemicircular outline, the convexity being anterior. 
* Professor A. Milne-Edwards informs me that the skuU attached to the skeleton in the Paris Museum 
evidently belongs to another animal. 
