MESOZOIC VERTEBRATA. 
33 
osities. The distal extremity of the humerus looks much like that of a 
tibia. It is truncate, and its long axis is in the plane of the tuberosities of 
the head. Its outline is oval, one end narrowed to an angle and the other 
broadly rounded. The surface is roughened with coarse pits. 
The distal extremity of another long bone, 5iost probably the ulna, is 
more robust than that of the humerus. The shaft is a flattened oval, and 
the articular extremity is a wide and somewhat irregular oval, the greatest 
transverse diameter being nearer one end. The articular surface is rough¬ 
ened with coarse pits. 
Three metapodials were found in immediate proximity to each other, 
two in nearly their normal relations and one slipped forward. They are 
neither remarkable for length nor abbreviation. The proximal ends are 
truncate and the distal ones convex, but without distinct median grooves 
or lateral angles. Both extremities are moderately expanded, and the 
shafts are contracted at the middle. The external bone is a little shorter 
than the two others, and is more flattened. It has a slightly defined con¬ 
vex head, with an adjacent prominent but ill-defined lateral crest. The 
larger of the longer bones has a crest at one angle, like that of an olecranon 
process. The proximal end of the same bone is massive, and is trapezoidal 
in outline. The outline of the corresponding head of the adjacent bone is 
triangular. A marked character of these bones is the rough or pitted sur¬ 
face of their articular extremities, except the distal end of the shorter bone. 
The shafts are solid, and filled with nearly equal coarse cancelli. 
The bones above described are evidently those of a Dinosaurian rep¬ 
tile, and they present characters which have not been previously observed 
in any other genus of the order. The form of the articular extremities of 
the humerus distinguishes it from the other known genera, especially from 
those of the European Trias. 
The rugose articular surfaces are also peculiar, indicating less than the 
usual mutual movement of the bones upon each other. A cartilaginous 
cap is indicated, which was probably the element from which' the mamma¬ 
lian epiphysis was derived. The sculpture of the surfaces is coarser than 
that to which epiphyses are attached in the Mammalia. The name of the' 
genus expresses this character. 
3 
