Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/109

1869.] x. p. 204, tab. 249. figs. 34, 5. This author studied the distal extremity of a tibia, with applied fibular condyle, from Honfleur, which he was not able to assign to any known species or genus, but which he, with his usual sagacity, included in the chapter devoted to Megalosaurus. He however regarded the face of the tibia receiving the condyle-bearing bone as the inner instead of the anterior, stating that the tibia is laterally instead of antero-posteriorly compressed; so anomalous is this structure among Vertebrates. He regarded the bone as the astragalus, and did not perceive any connexion between its ascending apophysis and a fibula, partly because a fibula with distinct distal articulations was received with the same bones.

"The fibular condyle possesses an articular facet on its exterior extremity (anterior, Cuvier), probably adapted to a corresponding face of a calcaneum. Its plane is transverse, and does not cover the whole extremity, the anterior margin and a knob on the antero-superior part of the extremity projecting beyond it. Exterior to the middle of the upper margin of this piece, and at the internal base of the ascending apophysis, it is perforate, as is the cavity above the condyles of the humerus in the higher apes, and may have received a similar coronoid process of an astragalus.

"As compared with the species examined by Cuvier, this fibular condyle has a less elevated form; in Cuvier's specimen the ascending apophysis was flatter, broader, and directed towards the calcaneal facet instead of from it; it lacked the submedian perforation. Its tibial face appears to have been rounded, not angulate. The tibia presented an ascending ridge to the face by which the ascending apophysis was applied; in the Lælaps aquilunguis there is no ridge, the apophysis reposing in a slight concavity. This apophysis, like the slender portion of the fibula, is composed of dense bone . . . . . . ..

"The direction of the condyle indicates the articulation of the tarsal elements to have been at a considerable angle with the shank of the leg, and that the animal was entirely plantigrade and was unable to extend the foot in line with the lower leg. The animal's weight was, no doubt, shared by another tarsal bone, besides the astragalus, owing to the anterior position of the former.

"In most known Dinosauria the relations of the tibia and fibula are similar to those in the modern Lacertilia. It would appear, then, that the class existed under two ordinal modifications: the first, including Scelidosaurus (Ow.), Hylæosaurus (Mant.), Iguanodon (Mant.), and Hadrosaurus (Leidy), may be called the ; the second, including Lælaps (Cope), and probably Megalosaurus (Buckl.), may be termed the ."

Prof. Cope's description leaves no doubt that Lælaps had the tibia and the anomalous bone which articulates with it, distally fashioned in the same way as in Megalosaurus, the Honfleur reptile, and Poikilopleuron; but it will become clear by and by that the