WEALDEN FORMATIONS. 17 



The femur. Tabs. VII and VIII. 



The fine specimen of this bone, 32 inches in length, of which two views are given 

 in T. VII, was discovered in the Oolitic slate at Stonesfield, originally formed part of 

 the rich collection of Fossil Remains belonging to the Earl of Enniskillen, f.r.s., and 

 has recently been transferred, with other parts of the Megalosaurus, from the same 

 collection to the British Museum. 



The head is subhemispheric, with the lower margin more freely projecting over 

 or beyond the under part of the neck than appears to have been the case in the 

 Iguanodon.* Viewed from behind, as in fig. I, or in front, the head of the femur 

 appears to be the convex termination or production of the somewhat expanded and 

 posteriorly flattened upper end of the shaft ; but, viewed from the inner side, where 

 the great trochanter, c, is seen relieved from the shaft of the bone, the head of the 

 femur has the appearance of being supported by a long and oblique neck, more slender 

 than the shaft. The great trochanter is broad but not much produced, being, as it 

 were, somewhat crushed down upon the shaft. The well-marked groove defining its 

 upper part from the neck, reminds one of that which defines the same part of the upper 

 trochanter in the Iguanodon ; but the fissure is narrower and deeper in that Dinosaur 

 than in the present genus. The inner trochanter, T. VII, d, is situated higher up, 

 and is less produced than in the Iguanodon : it has also a broader base, which is 

 extended further upon the hinder surface of the shaft of the femur. I have not seen 

 any femora of the Megalosaurus in which the two trochanters were so nearly opposite 

 one another, as is represented in the figures of that bone given in Dr. Buckland's 

 original Memoir : the upper end of the specimen from which that figure was taken, 

 had been more mutilated than in the original of the figures in T. VII. Below the 

 inner trochanter the shaft of the femur assumes a subquadrate transverse section, 

 with the angles rounded ; and, near the lower end, begins to expand into the con- 

 dyles. The anterior or rotular interspace, T. VIII, g, is much less deep, and is broader 

 than in the Iguanodon ; the posterior or popliteal interspace, id. h, more resembles in 

 size and depth that in the Iguanodon, but it is more flattened at the bottom. The outer 

 condyle, fig. 1,/, has a moderately deep and wide longitudinal impression externally, 

 which marks off the hinder projecting part of the condyle, which is relatively narrower 

 than in the Iguanodon ; the inner condyle, e, which is the largest and most prominent 

 of the two, is almost flat upon its inner side. The figure, of the natural size, of the 

 distal condyles, in T. VIII, taken from the best preserved specimen of the femur of the 

 Megalosaurus in the British Museum will serve better than verbal description to convey 

 a just idea of the modifications of this articular end of the bone in question. 



* See T. XV, ' Monogr. Wealden Reptilia,' 1854, fig. 1. 



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