148  Dr.J.C. Warren on the Osteology and Dentition of 
expressed on this point is undoubtedly demonstrated to be exact. 
This existing submaxillary tusk is eleven inches long, and is si- 
tuated on the left side of the symphysis of the lower maxillary 
bone: on the right side is seen the remnant. of a socket, which 
has been filled up, with the exception of about an inch of its 
anterior part. 
The teeth are four in the upper and four in the lower jaw; 
the points are somewhat worn, but in other respects these teeth 
are perfect. The anterior have six eminences ; the posterior eight, 
with quite a prominent heel. The front tooth measures four 
inches by three; the posterior seven inches by three and three- 
quarters. In this respect they accord with those in the other . 
Mastodon giganteus, of which we have spoken above. But in 
the smaller heads accompanying the latter the number and forms 
of the teeth were different. The descriptions, as minuted in Oc- 
tober last, were as follows :— 
“In the youngest of the heads there are three teeth on each 
side in the upper and lower jaw, of which one, the posterior mo- 
lar, is not fully developed. In this tooth we have only the erown 
lying imbedded in its socket, but so loosely that the finger being 
passed into the cavity of the alveolus is made to penetrate the 
cavity of the crown. The two anterior teeth are perfect, and 
contain each six eminences in three rows. At the anterior part 
of the jaws, in front of the teeth on each side, is an alveolus filled 
up. The upper and lower jaw nearly correspond. This is the 
smallest head and evidently that of a young animal; one tusk 
being only eight inches long on the outside of its socket, the other 
being broken. 
“In the second head, or that of middle size, and this is the 
most perfect of the three, there are, as in the preceding head, 
three teeth on each side of each jaw. In addition, the anterior 
tooth on the left side of the lower jaw, although very much worn, 
had not dropped out, but was readily removed by the fingers. 
The surface of its crown was worn quite flat, and one of the fangs 
wholly absorbed. The anterior tooth on the right side of the 
lower jaw and both from the upper had dropped out, and their 
alveoli were nearly filled up; thus making thirteen teeth in the 
whole. 
“In the third or largest-sized head there are only two teeth 
on each side of each jaw fully developed, and no appearance of a 
germ, making the whole number but eight. These teeth are 
much larger than those of the preceding heads, and the posterior 
tooth has, in addition to eight eminences arranged in two longi- 
tudinal rows, a terminal eminence or heel. 
“ Besides these heads and their appendant lower jaws, there 
are in this collection two separate lower jaws, both of them be- 
