266 KANSAS UNIVERSITY SCIENCE BULLETIN. 



The tibia (plate LVIII, figure 4) is represented by the lower 

 end of the bone belonging to the right side. Firmly coossified 

 with it is the astragalus, which rises into a rather prominent 

 ascending process on the anterior surface. The union of the 

 astragalus with the tibia is so complete that were one to view 

 the specimen from the posterior side its presence would never 

 be suspected. On turning the bone over, however, the astraga- 

 lus is distinctly seen, as is shown in the figure. The spine of 

 the astragalus is broken off, but judging from the groove for 

 its reception it must have been nearly 80 mm. in length. It 

 measures 50 mm. in width at the base. The tibia measures 

 145 mm. in width distally. The articular surface is broad and 

 pulley-shaped. There is a broad, shallow, trochlear groove 

 which is bounded by two rounded projections. The groove 

 runs up prominently on the posterior surface of the bone but 

 is not so prominent on the anterior surface. From the nar- 

 rowness of the broken surface of the bone, only 50 mm. in 

 diameter, one would judge that the shaft of the tibia was very 

 slender as described by Hulke (18) in Hylseosaurus and in 

 Polacanthns (19). It resembles these forms also in that the 

 shaft of the tibia is triangular in cross section, forming in 

 this case a nearly isosceles triangle. The section shows a 

 marked difference between the exterior of the bone, which is 

 smooth and compact, and the interior, which is coarsely can- 

 cellated. 



The fibula (plate LIX, figures 4 and 5) is represented by the 

 proximal and distal portions of the bone belonging to the right 

 side. The proximal end, which is subtriangular in cross sec- 

 tion, measures 85 mm. in width and is considerably expanded 

 as compared to the shaft. The upper end is so weathered that 

 no traces of the rugose surface for the attachment to the tibia 

 are left. However, one side is flattened as if for such a union. 

 The external side of the head is marked by a rather prominent 

 condyle, which projects some 5 mm. from the surface. The 

 shaft of the bone is very slender. At a distance of five inches 

 from its upper end the fibula measures 20 mm. by 30 mm. in 

 diameter being thicker antero-posteriorly than from side to 

 side. In structure the fibula is much like that of the tibia, 

 already described. The distal end, also, triangular in cross 

 section, is of the same proportions as the proximal end. 



The metatarsals (plate LVIII, figure 7) are represented by 



