Wealden of Brighstone Bay. 445 



section of the cliff was watched at brief intervals, and from a small 

 slip at the same spot a left femur was obtained. 



The bone was broken in its fall. The upper and median trochanter 

 and the posterior moiety of the inner condyle were destroyed. The 

 distal end had been much damaged while in a soft condition, the 

 outer condyle being completely doubled back and the preserved 

 portion of the inner condyle twisted round some distance anterior to 

 its true position. Later, from the same place were obtained the right 

 and left ischium. The former is perfect, but the latter has lost 

 about 10 mm. of the anterior acetabular portion, the obturator 

 process is bent out of position, and the shaft of the bone has been 

 broken, slightly twisted (not the natural twist) and cemented in that 

 position . 



The caudal vertebrae found in situ were lying at right angles to 

 the face of the cliff, the posterior being innermost. Although many 

 rolled and odd bones and teeth have been found, the present is the 

 largest number of associated remains of Iguanodon yet found in the 

 Isle of Wight. 



The Sacrum. — The sacrum possesses five vertebrae. The centra 

 of two anterior vertebrae are anchylosed to these, but the neural 

 spines and arches are lost. These two centra exhibit on the right 

 "side wing-like processes placed vertically. The transverse sacral 

 ribs spring from the neural arches as bars of bone, and continue thus 

 to their extremities. The three posterior are fused throughout their 

 length to a plate of bone. This plate between the second and third 

 ribs passes inwards and unites with the centrum beneath the first 

 sacral rib. This rib and the second, for the greater part of their 

 length, are free from the plate and rise well above it. The exterior 

 lateral border of the plate forms a deep upright wall. On a ventral 

 view, this plate is roughly shield-shaped, and the width across the 

 shoulder, which is situated under the third rib, nearly equals the 

 length of its sides. These sides have a slightly concave outline. 

 The posterior border is straight. 



There are four sacral foramina. 



llie Ilium. — The form of that portion of the ilium preserved is 

 close to that figured by Professor L. DoUo,^ and as the other bones 

 are identical, there cannot be any doubt that the forms of the missing 

 pre-post-acetabular extremities were similar. 



The Puhic Bone. — The pubic bone is a remarkably thin plate, the 

 width at the anterior end being one-seventeenth of the depth. It 

 is moderately thick near the acetabular margin, but considerably 

 increases superiorly for union with the ilium. The anterior third 

 of the bone is expanded into a broad circular plate, which is more 

 than half as deep as in the median region of the shaft. This disc- 

 like extremity is quite diffei'ent from the spatulate form of that of 

 /. hernissartensis. 



The Ischium. — The ischium is hammer-headed in form ; its preaxial 

 end is not nearly as robust as the postaxial, which is much thickened 



^ L. Dollo, " Premiere Note sur les Dinosauriens " : Bull. Mus. E. Hist. 

 Nat. Belg., vol. i, pi. ix, fig. 1. 



