348 T'ransactions.—Geology. 
giving it more the look of a cetacean than a reptilian limb-bone. The distal 
extremity is flattened at right angles to the greatest expansion of the proximal, 
and has two distinct, slightly concave, articular surfaces to receive the ulna 
and radius. The plantar surface is smooth and slightly concave. The palmar 
surface slightly convex, and has a bold, rugose tuberosity in the middle to 
receive the attachment of the bicipital tendon, indicating powerful rotatory 
movements of the limb. 
DIMENSIONS. 
Inches. 
Length sie s 115 
Diameter—articular surface 5 
Diameter—nec 3 4 
Length—trochanteroid surface 4:5 
Width b а 2:5 
Width— middle of bone ... 4:5 
Thickness ae Wa 2:5 
Width— distal extremity ... 9 
Thickness Ey 2-5 
Radius.—A pentagonal bone, with thin external margin and convex 
articular surfaces, and with a notch on the surface in contact with the ulna. 
It has two carpal articulations. 
Inches. 
Length P 3 
Width fan a Ts i 2:8 
Ulna.—A hexagonal bone, with convex articulation. 
Inches. 
Length 3°5 
Width ues s A ss i ae 
Carpals.—The radial is cuneiform, with three articular surfaces and a 
bevelled external. 
Inches. 
Length is б eee 2 
Width 2 А Sa 3 
The intermedium is pentagonal. 
Inches, 
Length 2:5 
Width 2:5 
Ulnare is hexagonal, with five articular surfaces. 
Distal Carpals.—1st has four articular surfaces, is rounded, and channelled 
. externally. 
Length 
Width “i = 
It articulates with two phalanges. 
Inches, 
2:5 
2nd also articulates with two phalanges, having, in all, five articular 
surfaces, 
3rd is also pentagonal; articulates with only one phalange and the «nare; 
the other surfaces not having perfect articulations. 
