230 Prof. H. G. Seeley on Euskelesaurus Brownii. 



anterior edge, and is narrower posteriorly. The distal articu- 

 lation appears to descend downward and outward obliquely 

 below the tibia, and to have a trochlear surface convex from 

 side to side, concave from front to back. The fibula is only 

 preserved on the left side, and its distal extension (if not due 

 to displacement) appears to indicate tliat the calcaneum, which 

 is not preserved, must have been distinct from the astragalus 

 and have been a relatively small bone, longer than wide. 



The astragalus shows no indication of an ascending process, 

 in this respect resembling Scelidosaurus and Cuninoria rather 

 than any other English types ; this implies no affinity, 

 although the astragalus in Euskelesaurus is completely 

 separate from the tibia ; the resemblance is rather with the 

 Zanclodontida?, which Professor Marsh has characterized as 

 having the astragalus without an ascending process. 



The anterior face of the tibia is flattened, but without any 

 indication of an impression for the intermedium, which may 

 have been a small separate bone, as in Nortalotarsus, which 

 is not preserved in this fossil. The astragalus is transversely 

 oblong, measuring 5-^ inches from side to side in front by 3^ 

 to 4 inches deep. It is preserved in both the right and lelt 

 limbs. Its proximal surface is horizontally truncated and 

 the distal surface trochlear, having a wide median channel, 

 which is shallow and convex from front to back. In the 

 right limb the external margin of the bone takes the form of 

 an unarticular talon on the posterior side, but of this there is 

 no trace in the left limb. Its presence may suggest a reduc- 

 tion in the number of digits in the hind limb. There is no 

 evidence that the fibula articulated w'itli the astragalus. 



The Proximal Ends of the Tibia and Fibula. 



The left tibia and fibula are only preserved for about 

 7 inches below the proximal articular surface. The contour 

 of the outline of the proximal surface of the tibia is the usual 

 subtriangular form, measuring 7 inches from front to back and 

 5^ inches from side to side. The posterior margin is sliglitly 

 concave from side to side, and the posterior surface of the 

 bone is markedly concave from above downward. Tiie 

 internal border is oblique to the hinder border in the usual 

 way, and this part of the shaft is convex as it extends forward 

 to form the cnemial crest, the proximal extremity of which is 

 broken away. The external surface is short and concave 

 from front to back, and approximately at right angles to the 

 posterior surface ; but it is obscured, because the fibula lies 

 in contact with it, displaced backward, witli the tibial surface 



