148 Dr. J. C. WaiTcn 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 j 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 crown 

 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- 



