4 FOSSIL REPTILIA OF THE 



dilian and Lacertian characters, with superinduced Dinosaurian peculiarities, analogous 

 to the plan of structure which I have had occasion to point out in other parts 

 of its fossilized remains. So far as the Dinosaurian peculiarity of a reduced number 

 of functional toes prevails, that order departs further from the general Reptilian type 

 than do the existing Crocodiles and Lizards. 



Having premised these general remarks on the fossils in question, I proceed next 

 to point out the chief characters of the constituent bones of the foot. 



The rudimental metapodial of the first or innermost toe (T. I, II, III, i) articulates 

 by its proximal end with a notch, 9 lines in diameter, at the middle of the inner 

 (tibial) surface of the second metapodial ( n). It seems not to have been anchylosed 

 at this part, from the circumstance that the slender bone has been broken, 

 soon after death or interment, and the upper portion has been displaced obliquely 

 from the lower half, vdiich maintains, perhaps through anchylosis, its natural position; 

 the displaced portion is cemented in that position by the hardened matrix to the con- 

 tiguous large metapodial.* The rudimental metapodial, 9 lines by 6 lines in the 

 two diameters of its proximal end, gradually becomes more slender as it descends ; 

 its lower half is trihedral, and stands rather sharply out from the large metapodial (n); 

 its extremity is broken off; the large and small diameters of the lower fractured end 

 are 5 lines and 3 lines. It is not probable that its presence was conspicuous beneath 

 the integument which covered it, but it may have supported a rudimental toe and 

 claw. 



The second metapodial (ib., n) is 8 inches in length, 4^ inches in the longest 

 diameter of the proximal end, 3 inches in that of the distal end. The bone expands 

 at both ends, more suddenly at the distal one ; it is convex on its free or tibial side, 

 flattened on the side next the third metapodial, with the anterior border produced 

 near the middle of the shaft into a process with a convex outline, and with a ridge 

 projecting from the inner and back part of the proximal end. This ridge has been 

 fractured. The outer or fibular angle of the back part of the proximal end is produced 

 towards the next large metapodial, but has likewise been fractured. The articular 

 surface at this end is flat, rather rough, showing vascular pits and other evidence of 

 having been covered, in the recent state, by a layer of fibro-cartilage : by which it was 

 articulated to the innermost tarsal or carpal bone. The distal articular surface is 

 convex from before backwards, slightly convex transversely at its anterior half, with 

 a middle concavity and lateral convexities, transversely, at the posterior half, which is 

 somewhat broader than the fore part of the joint, and with the outer (fibular) angle 

 produced. 



The inner (tibial) side of the distal end of this metapodial has a broad and shallow 

 depression for the attachment of a lateral ligament ; the articular surface is two inches 



* In the figure it is represented as restored to its natural position. 



