518 Geological Society. 



the supposition of the proportion of the femur which has been pre- 

 served be right, this bone, Mr. Owen says, differs from that of the 

 Iguanodon, not only in the want of a medullary cavity, but also in 

 the absence of the compressed second trochanterian process which 

 projects from the outer side of the middle of the shaft, and which 

 forms one of the several curious analogical relations between the 

 Iguanodon and Rhinoceros. The bone also expands more gradually 

 than in the femur of the Iguanodon, and the posterior part of the 

 condyles must have been wider apart in consequence of the posterior 

 inter- condyloid longitudinal excavation being longer and wider. Va- 

 rious other minor points of difference are noticed by the author. 



Tibia and Fibula. — The portion of a tibia which has been preserved 

 is compressed near its head, and the side next to the fibula is slightly 

 concave. The longest transverse diameter is eight inches nine lines, 

 and the two other transverse diameters at right angles to the pre- 

 ceding give respectively three inches three lines and two inches six 

 lines. The bone soon assumes a thicker form, its circumference at 

 about one- third from its proximal end being sixteen inches six lines. 

 The cancelli occupying the central portion of the bone are arranged 

 in a succession of layers around a point nearest the narrower end 

 of the transverse section. Lower down the tibia again becomes 

 compressed, and towards the distal end the transverse section exhi- 

 bits a plate bent towards the fibula, and its narrowest transverse 

 diameter is two and a half inches. 



The portion of the fibula is eleven and a half inches long. In the 

 middle it is flat on one side, slightly concave on another, and convex 

 on the two remaining sides. It presents the same cancellous struc- 

 ture as the tibia, but the concentric arrangement of the layers of 

 cells is more exact. Towards the opposite end of the bone the con- 

 cave side becomes first flat and is then produced into a convex wall, 

 terminating one end of a transverse section of a compressed and bent 

 thick plate of bone. 



Metatarsals. — These bones, Mr. Owen says, exhibit the charac- 

 teristic irregularity of length of the crocodilian metatarsals. Of two 

 imbedded in the rock, and considered by the author to be the inner- 

 most and second, the former or smaller measured one foot in length, 

 and the latter two feet, having a diameter of eight inches at its 

 greater and of four inches five lines at its narrowest or middle part, 

 and of six inches at its other extremity, which was imperfect. The 

 whole of the bone within the compact outer crust consisted of cells 

 varying from a half to two-thirds of a line in diameter. Portions of 

 four other detached metatarsals are described. 



Ilia, Ischia, Pubis, and Coracoid Bone. — These bones, the author 

 states, also conform to the crocodilian type. The remains of the 

 ilia are flat and nearly straight, and they gradually but slightly 

 widen towards one end. Of one ilium, a portion, twenty-five inches 

 long and ten inches across at the broadest end, is preserved, and of 

 the other a fragment twenty inches in length. 



The mesial extremities of the pubis and ischium are preserved in 

 the same block of stone. The pubis, Mr. Owen states, differs from 



