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species with a less heavy type of body. The Kimeridge Clay 
femur is relatively heavier than that from the Oxford Clay, 
and widens at the distal end in the the same way, but its 
proximal end is shaped as in the Corallian species, but is 
relatively wider. 
Professor Marsh has referred the Kimeridge Clay fossil from 
Swindon to the American genus discovered and restored by 
himself named Stegosaurus. Mr. Hulke has intimated his 
belief that the Oxford Clay species should be referred to that 
genus if it proves to have dermal armour of the plate-like type 
figured by Professor Marsh, which Mr. Hulke describes (Quart. 
Jour. Geol. Soc., Yol. xliii , p. 702), and Mr. Lydekker (Cat. 
Foss. Kept, and Amph. Brit. Mus., part 4, p. 251,) adopts 
this identification. It seems to me that no sufficient evidence 
has yet been brought forward to justify the identification. 
The massive thickness of both the proximal and distal ends of 
the femur in Stegosaurus in not paralleled, judging from 
Professor Marsh’s figures, in any of the femora which have 
been referred to Omosaurus. Stegosaurus appears to have been 
a heavier type of animal. There is no proof that Omosaurus 
possessed the great dorsal-crest of armour plates from which 
Stegosaurus takes its name, which are shown in Professor 
Marsh’s restoration of the skeleton. I concur with Mr. A. 
Smith Woodward in regarding the supposed armour plates of 
Omosaurus as the opercular bones of a fish which he has 
named Leedsia. 
There is no doubt that Omosaurus is allied to Stegosaurus , 
though the affinity may not be so close as has been supposed. 
And the relationship is important as showing the nature of the 
skeleton which was associated with this Yorkshire femur. The 
teeth of Stegosaurus are of the family typo of Acanthopholis; 
and teeth of this kind may be predicated for the Slingsby 
fossil. In Stegosaurus ungulatus as restored by Marsh, the 
length of the head of the animal is seen to be less than half 
the length of the femur. And if the head of the Slingsby 
animal was relatively as long it may have measured about 
twelve inches in length. 
In 1875 I brought under the notice of the Geological 
Society a new Dinosaur, the maxillary bone of which is about 
