tically to the plane of the ilium. A thin, slender, outer trochanter, separated from the upper end of the shaft by a narrow fissure, strongly recalls the similar process in the thigh-bone of Iguanodon. The shaft has an outward twist, larger, I think, than in Iguanodon. The femoral condyles are strongly developed, and they project very strongly backwards, separated here by a very deep intercondyloid groove. The anterior intercondyloid groove is worn away in the Mantell-Bowerbank femur, and it is effaced by squeezing in my specimen; but I have seen it a well-marked deep groove, differing, however, from the groove in the femur of Iguanodon by the absence of overhang, the lips of the groove in Hypsilophodon not being inclined towards each other, and not forming the tunnel which marks the thigh-bone of the great Dinosaur. The length of my femur cannot now be ascertained; but those of three others were 7, 7, and 5⋅12 inches.
Tibia (fig. 8, a).—I have secured in one block the distal end of the tibia with the pes. The length of this shin-bone cannot be learned; but that of a beautifully perfect example from another individual was 9⋅25 inches, the femur of the same being 7 inches long. The proximal end of this bone was divided into two condyles, answering to those of the femur, but not so strongly marked as these were; and beyond the outer condyle a large crest projected forwards and outwards from the front of the upper part of the shaft. The axis of the shaft has a strong twist in the same direction as that of the femur. The distal end is transversely expanded, and it closely repeats that of the Iguanodon.
The fibula is very imperfectly known to me; I believe it to be rather shorter than the tibia.
Pes (fig. 8).—The astragalus is disconnected from the tibia in my specimen; but in two other examples I have seen it attached to it. Its lower surface is pulley-shaped, convex from back to front, and sinuous transversely, being in this direction convex laterally and hollow mesially. The upper surface is concave from back to front, and in this direction it is subdivided by a ridge which marks off two facets answering to those on the distal articular surface of the tibia. The anterior margin is a very thin lip: in my specimen the extreme edge has been broken off; but its thinness is such that it cannot have here been produced into a bird-like ascending process. The posterior border is stouter.
Under the distal end of the tibia, and partially hidden by it, are two small bones, probably tarsals; the larger and outer one may be a calcaneum.
There were certainly four (if not five) toes, of which the outer three are well preserved; their ossicles still maintain, with only slight disturbance, their proper relations. The metatarsals are long and stout; their proximal ends have been flattened by a hard sand-stone nodule. The middle one (the longest) measures 2⋅8 inches long; the outer one is 2⋅3 inches, and that on the inner side of the central one is 2⋅5 inches long. Displaced, and lying beneath these three, athwart them, I discovered an ungual phalanx, and not far
