84 
THE EACES OF THE GALAPAGOS. 
ulna has its radial edge but slightly emarginate, and is twisted round its longitudinal 
axis, so that the transverse diameters of its proximal and distal dilatations would inter- 
sect each other at an angle of about 50°. The olecranon is not much developed. The 
articular facet of the radius for the articulation with the humerus is a rectangular 
triangle, with the point directed backwards, and the shortest side in front. 
T. elepTiantopus, T, ephippium, 
790 millims. long. 840 millims. long. 
millim. 
millim. 
Length of ulna 
137 
155 
Least width of ulna 
28 
26 
Length of radius 
121 
149 
50 
51 
Only a few of the carpal bones have been extracted from the specimen, among them 
the scaphoid and " intermedium," which have remained perfectly separate. 
In the pelvis (Plate LIV. fig. A) we notice, in the first place, that all the sutures are 
present, and that growth was still proceeding in their vicinity. However, on the whole, 
the pelvis does not differ in a marked manner from that of T. elephantopus, except that 
the symphysial bridge is broader (the obturator foramina consequently narrower) and 
not so deep. The posterior part of the ossa ilii also is broader than in the other species. 
Other slight differences of form may be seen from the accompanying comparative mea- 
surements : — 
T. elephantopus, T. epJiippium, 
790 millims. long. 840 millims. long, 
millim. miUim. 
Longest inner vertical diameter of pelvis (from summit of ilium 
to symphysis) 170 160 
Longest inner horizontal diameter of pelvis. . . 132 118 
Shortest inner horizontal diameter of pelvis (between ilio- 
pubic prominences) 112 97 
Longest diameter of foramen obturatorium 42 42 
Width of symphysial bridge 26 35 
Depth of symphysial bridge 26 23 
Least breadth of posterior portion of ossa ischii 61 80 
Length of OS ilii 140 180 
Least breadth of os ilii , 30 27 
The femur is very similar to that of T. elephantopus (p. 68), with the exception of its 
proximal portion (Plate LIII. tig. B) : the head has an elliptical form, and does not rise 
above the level of the summit of the larger trochanter, as in T. elephantopus, but is con- 
siderably smaller ; on the other hand, the cavity separating the head from the trochanters 
