Thecodontosaurus and Palasosaurus. 153 



distal condyles are rounded from back to front, tlattcncd on 

 the inner side, and oblique on the external border. The bone is 

 l-HF inch thick at the condyle. This larger condyle is sepa- 

 rated by a concavity which extends on to the base of the 

 articular surface from the smaller external condyle, beyond 

 which is the oblique conij)res.sed external border of the bone. 

 The transverse width of the distal end is 2-{'^ inches. The 

 specimens of femur differ considerably in size and character; 

 some apparently indicate bones not more than 6 inches in 

 length and more slender than others, as though different 

 species were mixed together. 



The Tibia o/'Paljeosaurus. (Fig. 5.) 



The tibia figured in 1840 still remains the only complete 

 specimen. It is apparently in less excellent preservation at 

 the distal end than when originally drawn, and without the 

 aid of a second specimen its characters might have remained 

 in uncertainty. The specimen no. 76 is 7 inches long, very 

 slender in the middle of the shaft, and expanded at both 

 extremities. The transverse width of the proximal end is 

 2-ftr inches as exposed, measuring obliquely from the anterior 

 border of the cnoniial crest to the inner posterior angle of the 

 articulation. The width of the bone behind is about 1^ inch, 

 and its external lateral measurement is about as much. As 

 in the s{)ccimen 77 a figured by Professor Huxley, the external 

 border has a distinct fibular concavity ; but the forms of the 

 proximal articular surfaces of the two specimens are different. 

 The cnemial crest is elevated slightly above the articular 

 surface for the femur. The posterior margin of the proximal 

 femoral articulation of the tibia is rounded in the usual way, 

 as though for contact with the condyles of the femur. The 

 shaft is slightly more than ^ inch wide in the middle, the 

 distal end is l-]\ inch wide, notched on the anterior border, 

 and has a subquadrate form. 



There is a remarkable general resemblance between this 

 bone and the tibia which 1 have described as Agrosaunis 

 (Quart. Journ. Geol. Soc. 1891, vol. xlvii. p. 1(J4), in which, 

 however, the expansion of the proximal end appears to be 

 relatively greater ; and the notch at the distal end aj)j)cars 

 to be in about a line Avith the cnemial crest, while in 

 Agrosaurus it is obviously lateral and on the fibular side. 



JSo. 53 (fig. 5) is a fragment a little over 3 inches long, 

 showing the distal end of a more slender tibia, in which the 

 bone wants the transverse expansion which characterizes the 

 type species no. 76. The distal end is subquadrate, about 



