118 



mode of production of these and similar arrests of develop- 

 ment. 



Professor Frazer read a letter from Mr. J. B, Maxwell, one 

 of the trustees of Princeton College, to Professor Henry, dated 

 Belvidere, Oct. 17, 1844, relating to the discovery of Mastodon 

 bones on the farm of Mr. Abraham Ayers, near Hackettstown, 

 New Jersey. 



There are portions of the skeletons of five Mastodons — one pretty 

 large — three of smaller size, and a calf: of the largest, only the 

 grinders — portions of the tusks (13 J inches in circumference,) and 

 some fragments of the larger bones remain — the rest having fallen to 

 pieces on being exposed to the air. The bones of the calf fell to 

 pieces in like manner, and no parts have been preserved except the 

 grinders and the tusks, which were five or six inches long, about 

 three-quarters of an inch in diameter, and seem to have projected 

 more than an inch from the bone. Of the other three, the skulls and 

 most of the larger bones are in good preservation. We measured 

 some parts of the largest of them, as follows : — 



Skull — from top of head at junction of the muscles of the neck to 

 end of bone between the tusks — 3 feet 4 inches. 

 „ Between the large cavities for the ears across the forehead — 



2 feet. 

 „ Orbit of the eye— vertical diameter, 6 inches. 

 „ Reniform orifice below the eyes, (communication between 

 trunk and brain, &c.) 10 inches across by 4 inches ver- 

 tically. 

 „ Oval orifice below this, (communication between trunk and 



throat,) 5i inches vertically by 3 across. 

 „ Tusk, from insertion, 2 feet 3 inches — whole length 3 feet 1 

 inch, and about 3 inches in diameter. 

 Pelvis, 4 feet 10 inches across, by 3 feet 8 inches. 

 Femoral bone, 3 feet long, 1 foot Ij inch in circumference in the 



middle. 

 Scapula, 2 feet 5 inches long, 2 feet 1 inch wide — measuring over the 

 projection. 



There were three grinders on each side above, and the same num- 

 ber below. The two others and the calf had four teeth on each side, 

 both above and below, but the forward ones were evidently " milk 

 teeth," which would have been shed at a more advanced age. In 



