A DINOSAUR FROM THE OXFORD CLAY OF GREAT ORANSDEN. 151 



condyles, the larger of which is on the inner side (figs. 1, 2, & 4, d) ; 

 and from this a sharp angular ridge extends towards the trochanter 

 on the middle of the shaft, so as to separate the flattened inner 

 side of the bone from the posterior side. The inner condyle mea- 

 sures 3 inches from front to back, and is 1| inch wide ; it is con- 

 vex on the posterior aspect, and is separated by an interspace of 

 fully | inch from the second or outer condyle. This interspace 

 constricts the articulation from back to front to 1^ inch. The con- 

 vexity of the second condyle is broken away (figs. 2 & 4, e) ; but 

 the articular part of the bone extends external to and beyond it 

 for 1| inch, terminating in a sharp outer angular process. The 

 back of the shaft between the condyles and for several inches 

 above them, is concave in length and concave from side to side, the 

 shaft there measuring only 1J inch from back to front. The margin 

 of the articulation is roughened with strong ligamentous attach- 

 ments. 



This genus differs from Megalosaurus in having a more compressed 

 shaft and more expanded extremities, in the position of the inner 

 trochanter near the middle of the shaft, and in the small extent to 

 which the external proximal Amphibian trochanter is divided from 

 the shaft. 



From Iguanodon it differs in wanting the distal anterior inter- 

 condylar groove characteristic of the bone in that genus, as well as 

 in all the characters which part it from Megalosaurus, except the 

 position of the inner trochanter, in which there is a close agree- 

 ment between Cryptosaurus and Iguanodon. 



EXPLANATION OF PLATE VI. 



The letters in all the figures have the same signification : — a, Mastiform tro- 

 chanter; b, Articular head; c, Inner lateral trochanter; d, Inner distal condyle; 

 <s, Outer distal condyle. The figures are half the natural size. 



Fig. 1. Inner aspect of femur of Cryptosaurus. 



2. Posterior aspect. 



3. Proximal articular end. 



4. Distal articular end. 



