344 ON THE FOSSIL BONES OF PACHYDERMATOUS QUADRUPEDS. 



animal. At the period of tlic publication of my first edition, I had 

 come to the conclusion that their disposition is in every material cir- 

 cumstance similar to that of the elephant. 



Mr. Jefferson having since sent me a very complete radius, I have 

 given a drawing of It (plate 24, figs. 5, G, 7), and I have compared it 

 attentively with that of the elephant. Its general form is pretty much 

 the same ; its superior facette is less contracted on the outside ; its edges 

 are more decided ; it is more angular ; its inferior part begins to grow 

 thick sooner, and is grosser in proportion towards the base. This 

 radius of Mr. Jefferson is 0,670 long ; the width of its superior extre- 

 mity is 0,130; that of the inferior, taken at the articulated facette, is 

 0,132 ; and a little higher up, at the thickest part, 0,160. 



The radius of the skeleton of Mr. Peale is •>' 5" &'" English, or 0.74.5 

 in length. It bears to the humerus a proportion of a little more than 6 to 

 7. In the elephant this proportion is as 6 to 8. Thus the fore arm of 

 the mastodon is longer, and its arm shorter in proportion, than are 

 those of the elephant. 



The difference of relative proportion between the humerus and the 

 shoulder blade is still greater. In the elephant it is as 8 is to 6-| ; that 

 is to sa}^, the humerus is One-fifth longer. In the mastodon, on the 

 contrary, it is a little more than as 8 is to 9. Thus the humerus is in 

 the latter animal shorter by a ninth. 



There is not the slightest room for doubting of the exactness of these 

 relative proportions, since the bones of the extremities having been 

 found together by Mr. Peale, it amounts to an almost positive certainty 

 that they belonged to the same animal. 



8. The large Bones of the posteinor Extremities. 



The Pelvis is much more depressed, in proportion to its width, than 

 in the elephant ; its aperture is also much narrower. This is observed 

 by Mr. Peale, and it may be seen by comparing the pelvis of the ske- 

 leton, plate 23, with that of my plate 7 upon elephants, and the front 

 section of the same pelvis, plate 24, fig. 10, with fig. 3 of the plate 13 

 upon elephants. This form of the pelvis must necessarily have ren- 

 dered the abdomen smaller and consequently less capacious than that 

 of the elephant — a circumstance which, taken in conjunction with the 

 structure of the teeth, has led us to look upon the mastodon as net be- 

 ing so exclusively herbivorous. 



Mr. Peale tells us, that the width of the pelvis of his skeleton is 5'' 

 8" English; but I am afraid there must be some tyj^ographical error 

 here, or else that he meant the circumference. 



2ndb/. The Femur was described before any of the other parts. 

 Daubenton m^ade a drawing of that in our Museum, in the Memoirs of 

 the Academy for 1762. In fact, its enormous mass strikes us with 

 astonishment at the fi.rst glance. Its immense width serves at once to 

 distinguish it from that of the fossil elephant. It is, moreover, flatter 

 from front to rear in its lower extremity, because the canal corres- 

 ponding with the rotula is there shorter. It is 1,088 long, and 0,44 

 wide at the top between the head and the great trochanter ; 0,29 at the 

 bottom, and 0,18 in the middle. Its antero-posterior diameter is 0,15 



