426 Dr. BucRLAND on the discovery of Bones 



is the i^io-antic metacarpal bone about to be described. The form of this bone 

 nearly resembles one in the collection of Mr. Mantell, which Cuvier saw, and 

 pronounced to be the metacarpal bone of the thumb of a reptile ; but much 

 exceeds it in size, measuring six inches in length, five inches in width at its 

 largest diameter, and sixteen inches in circumference at its posterior and 

 largest extremity. Its weight is nearly six pounds. 



The annexed drawing (Plate XLI. fig. 1. and 2.) being of the natural size, 

 o'ives an exact representation of it. It is, I believe, the largest metacarpal 

 bone which has been as yet discovered ; and if we apply to the extinct animal 

 from which it was derived, the scale by which the ancients measured Hercules 

 {" ex pede Herciilem"), we must conclude that the individual of whose body 

 it formed a part, was the most gigantic of all quadrupeds that have ever trod 

 upon the surface of our planet. The corresponding bone in the foot of the 

 largest living elephant is less than our fossil metacarpal by more than one- 

 half. The bone represented by Mr. Mantell (Plate XIV. fig. 4. 3. of his 

 fossils of Tilgate Forest), approaches the nearest of all those engraved by him 

 in this work, to our bone from Sandown Bay. He considers his fossil to be 

 most probably a metatarsal bone of the Iguanodon, and slates that he has one 

 such bone which measures four inches and a half in length, and thirteen 

 inches in circumference in the largest tarsal extremity. The colossal pro- 

 portions of a fragment of a femur in his possession, from Tilgate Forest 

 (Plate XVHI. fig. 1. of the same worl-), which measures twenty-three inches 

 in circumference in the smallest part, fufficiently accord with those of his me- 

 tatarsal bone last mentioned, as well as of our metacarpal bone from the same 

 formation in the Isle of Wight ; and give strong probability to the opinion 

 that all these three fragments of the skeleton of a reptile of such extraordinary 

 stature may be referred to the Iguanodon. It is obvious that these supposed 

 metacarpal and metatarsal bones are much shorter and thicker in their pro- 

 portions, than the metacarpal or metatarsal bones of any living lizards or cro- 

 codiles ; but when we consider the enormous weight, which the foot of an 

 animal whose femur was twenty-three inches in circumference must have 

 sustained, a reduction of length and increase of bulk in the bones which 

 supported such a colossal frame, must have been attended with many mecha- 

 nical advantages*. 



* The following are among the reasons which induce me to assign to our bone from Sandown 

 Fort, the place I have given it as the metacarpal bone of the left thumb, or possibly the meta- 

 tarsal of the left great toe : — 



1st. Its want of symmetry in the two sides, as well as its enormous size, forbid us to give it a 

 place among the phalangeal bones of any of the fingers or toes. 



2ndly. Its outward curvature towards the right is such as could not have taken place in any other 



