38 
THE EACES OF ALDABRA. 
millim. 
Length of humerus 180 
Circumference of the narrowest part of the shaft 83 
Longest diameter of the head 36 
Shortest diameter of the head 30 
Extreme breadth between the condyles 63 
The bones of the forearm differ in several respects from those of T. elephantina and 
T. daudinii. The shaft of the radius is laterally strongly compressed and much nar- 
rower than deep. The ulna has its radial margin much curved, so that a wide oval 
vacuity exists between this bone and the radius. The olecranon is as prominent as in 
T. daudinii, the articular surface forming a steep decline towards that of the radius. 
The arrangement of the carpal bones is the same as in the other two species. The 
comparative measurements of the bones of the forearm in the three species are : — 
T. elephantine!. T. daudinii. T. ponderosa. 
Spec. c. Spec. I. Spec. l\ 
millim. 
millim. 
millim. 
millim. 
millim. 
Length of ulna 
195 
110 
142 
150 
112 
Least width of ulna 
31 
18 
22 
29 
18 
Length of radius 
175 
97 
130 
145 
112 
Least circumference of radius 
85 
40 
63 
67 
46 
Of the ])elvis (Plate XVIII.) two specimens are in the British Museum. All the 
sutures have disappeared ; the iliac bones are broad and stout, and the vertical and 
horizontal diameters of the pelvis are nearly equal. The lower part of the pubic bones 
is gently inclined downwards, prolonged into a tapering lamelliform extremity, and 
provided below with a sharp median crest. It emits laterally a long, strong process, 
which is obliquely directed outwards. The posterior part of the ossa ischii is of mode- 
rate width, concave above, terminating in a short hamate posterior process on each side, 
and provided with an exceedingly high symphysial crest below, which, expanding 
towards behind, forms a large triangular tuberosity. Lateral margin of the ossa ischii 
excised in the shape of a C. Obturator foramina very wide. 
1st spec. 2nd spec, 
millim. millim. 
Longest inner vertical diameter of pelvis (from summit of ilium to symphysis) ... 158 116 
Longest inner horizontal diameter of pelvis 164 129 
Shortest inner horizontal diameter (between ilio-pubic prominences) 97 82 
Longest diameter of foramen obturatorium 54 41 
Width of symphysial bridge 19 10 
Depth of symphysial bridge 45 30 
Least breadth of posterior portion of ossa ischii 63 55 
Length of os ilii 116 100 
Least breadth of os ilii 39 27 
