310 Mr. H. G. Seeley on Acanthopholis platypus, 



the compressed apex upward. As preserved, this surface 

 measures 



In height 3| inches. 



From side to side where widest l| inch. 



The inner flattened vertical surface of the bone is somewhat 

 triangular in outline ; its moderately concave superior margin 

 and its more concave inferior margin approximating towards 

 the distal end, but remaining separated by a convex expanded 

 outline of the distal articulation. The whole inner surface is 

 gently concave from front to back : at the back, where 3| 

 inches deep, it is flat ; in front, behind the articulation, where 

 an inch deep, it is convex from above downward. The ex- 

 ternal surface is convex and oblique from above downward 

 proximally ; but at the distal end, by the form of the articula- 

 tion, it becomes angulated, so that the external slightly convex 

 part is short and vertical, and the superior convex part hangs 

 a little to the inner surface. In length this surface is gently 

 concave. The extreme length of the bone as preserved is, on 

 the inner side, nearly 4 inches. The distal articular surface 

 is somewhat abraded. It is in outline concave below, higher 

 on the outside, compressed on the inside, and convex above, 

 so as to be ear-shaped. As preserved, it measures 2| inches 

 from side to side, and nearly 2 inches high at the outer part. 

 The surface is depressed in the middle towards the under part, 

 where it terminates in an oblique transverse thickening : it is 

 ' not parallel with the proximal surface, but inclined to it so as 

 to look externally away from the second bone. The under 

 surface is rhomboid, half as long again as wide, wider in front 

 than behind, concave in length, and slightly convex from side 

 to side. 



Externally the bone shows a few small nutritive foramina ; 

 and in a corresponding bone from another species (marked, in 

 the Woodwardian Museum, J. e. 25) foramina are conspi- 

 cuously numerous on both the proximal and distal ends, 

 though, probably owing to the state of its preservation, no 

 trace of them is seen in the specimen now described. 



The second bone is strong, longer than the first, and less 

 stout ; it is 5f inches long. The proximal articulation is four- 

 sided, with the sides nearly parallel ; it is oblique to the distal 

 articulation, inclining towards the third metapodial bone ; it 

 measures 4j inches in height, and about 2 inches from side to 

 side at the proximal and distal ends, and 1| inch from side to 

 side in the middle. The long outline towards the first bone 

 is straight, that towards the third bone is moderately concave ; 

 the superior outline is slightly convex, and the inferior outline 



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