696 



ME. J. W. HTJLKE ON 



originally existed, but that this has been greatly exaggerated by 

 compression since death. 



Ribs. — A nearly complete vertebral rib, being about three times 

 as large as the longest rib in the articulated skeleton of an 

 Elephant of average stature preserved in the Museum of the Royal 

 College of Surgeons, gives an idea of the great girth of the thorax in 

 this Dinosaur. This rib presents a distinct neck and shaft, which 

 include between them a present angle of about 90°. The vertebral 

 end of the rib is unforked ; the capitular and the tubercular articula- 

 tions were therefore both seated above the level of the neuro-central 

 suture on the transverse process of the corresponding vertebra. In 

 extant Crocodilians this arrangement obtains first at the 11th or 

 12th vertebra, and this rib is usually the third in that segment of 

 the vertebral-costal series in which the vertebral ribs are connected 

 with the thoracic sternum by sterno-costal cartilages. So far, 

 therefore, as the Crocodilian analogy warrants the inference, this 

 Dinosaurian rib belonged to the scapular region of the thorax. The 

 length of the neck of the rib, taken from its capitular end to the 

 angle which it includes with the shaft, measures 34*5 centim., and 

 that of the shaft, which has a slightly /-shaped double curve, taken 

 along a straight line between its extreme points, is 152 centim. 

 The upper border of the neck is approximately straight, while the 

 lower border makes a regular downward curve, and this part of the 

 rib rapidly expands in its vertical dimensions, attaining a maximum 

 measurement of 20 centim. across the angle. Prom here the 

 l)readth declines, becoming only 9-7 centim. at the distance of 

 41 centim. from the angle. This reduced breadth continues with 

 little variation for a considerable distance, and then augments 

 towards the ventral end, where it is 13 centim. The expanded part 

 of the neck and angle of the rib is a relatively angularly folded 

 plate, exhibiting in its posterior or visceral aspect a deep, longi- 

 tudinal hollow. The outer surface exhibits the commencement of a 

 longitudinal ridge which subdivides this surface into a posterior 

 part somewhat convex transversely, and an anterior part slightly 

 hollowed. The part of the rib behind the ridge is stouter than 

 that in front of it. In its vertebral third the cross-section of the 

 shaft of the rib is a triquetrous figure ; beyond this the shaft 

 becomes flattened as its breadth increases towards its ventral end. 



Pelvis. — The ilium, ischium, and the pubis all contributed to the 

 composition of the acetabulum, the last-mentioned bone not being 

 excluded from it as in Crocodilians. The pubis and the ischium 

 diverge, the former being directed forwards, downwards and 

 inwards, the latter backwards, downwards and inwards ; the pubis 

 also is not divided into a prse- and a post-pubic segment : in both 

 these respects this pelvis differs from that of the Iguanodontidae. 

 One ilium only, and this in a very mutilated state, was obtained : I 

 regard it as the right. Its present length is 84*5 centim. Of this 

 the chord of the acetabulum is about 40 centim. long, and the length 

 of the prseacetabular portion 45 centim. The maximum breadth of 

 the acetabular surface is 17*5 centim. between its inner and its 



