392 mk. R. w. nooLEr on the [June 1913, 



The Pteroid. 



The right pteroid (PI. XXXVI, fig. 1, pt. & PI. XL, fig. 1) was 

 lying parallel to the radius, with its proximal end overlapping 

 (15 mm.) the radius and over the position of the lateral carpal. 

 The last-named bone had become displaced. The pteroid is of the 

 usual whip-like form. It has a flattened expansion at its proximal 

 end, tapers to a point at the distal, is hollow, of small size, and a 

 fourth of the length of the antebrachium. The dorsal border of 

 the expansion is convex, the ventral is compressed and flat. The 

 outer surface has pronounced longitudinal muscle-striae ; the inner 

 is a very shallow concavity, in the centre of which is an oval 

 foramen 9 mm. long and 4 mm. wide. 



The Wing-Phalanges. 



All the wing-phalanges are hollow. The portion preserved of 

 the right first phalange (PI. XL, fig. 2, W.jph.) is 330 mm. long. 

 The general form of the bone is of the usual type. The proximal 

 articulation is three times the diameter of that of the centre of the 

 shaft. The articular surface for the ulnar metacarpal is concave, 

 and extends along the ventral half of the bone. Immediately 

 dorsal to this occurs the usual epiphysis, which is more pointed, 

 and directed to the dorsal side, than in other forms. Lying ex- 

 ternally to this, and occupying the space between it and the 

 dorsal border, there is a small and deep semicircular emargination 

 (PI. XL, fig. 2, see.), bordered on the dorsal edge by an outgrowth 

 of the bone, directed dorsally. In this a small rod-like bone 

 (PI. XL, fig. 2, s.b.) is placed and perhaps articulated. Both right 

 and left first wing-phalanges possess this bone. The proximal end 

 of the right first wing-phalange preserved in the B.M. P/176 spe- 

 cimen has two small, round, splint-like portions of bones, abutting 

 against the dorsal half of the articulation. 



The Second Wing-Phalange. 



The second wing-phalange (PI. XXXVI, fig. 1, 2 iv.pli.) seen 

 in the Atherfield specimen Xo. 1 is not entire, on account of the 

 missing section. Both articular ends are expanded. There is a 

 great variation from the other wing-phalanges in the form of the 

 shaft ; the bone is triangular, the apex being on the dorsal border ; 

 the preaxial and ventral surfaces are concave (the latter more so 

 than the former), and the postaxial convex. It soon passes into 

 this form at the proximal end, and as quickly resumes the normal 

 shape at the distal. This peculiarity is not occasioned by crushing. 

 The bono is much thicker than that in other parts of the skeleton. 



The Third Wing-Phalange. 



The portion recovered of this phalange (PI. XXXVI, fig. 1, 

 3 iv.ph.) is 127 mm. long. It is convex dorsally and ventrally, and 

 concave pre-postaxially. 



