APPENDIX. 217 



PLATE XVHI. 

 The Base of the Shawangunk Cranium. — Pages 12, 114. 



PLATE XIX. 

 The Occiput of the Shawangunk Head. — Pages 15, 113. 



PLATE XX. 



Fig. 1. — Vertical section of a penultimate molar of Mastodon Giganteus. This tooth has 

 lost its roots, and displays between then bases a portion of the cavity or hollow. The three 

 textures belonging to the teeth of this species are distinctly shown. In the interior is the 

 dentine or substantial texture, constituting the body of the crown ; circumscribed internally by 

 the hollow or cavity of the tooth, and externally by the enamel, which is very broad and distinct. 

 The enamel invests the crown, and is a quarter of an inch in thickness. Under the cleft it pre- 

 sents two olive-like lobes, placed at the point of union between the ridges, where the greatest 

 strength is required. On the outside of the enamel is seen the very thin line of cement which 

 covers the enamel and descends to the roots. The part which invests the enamel of the crown 

 is very thin, and only visible by the aid of a microscope in ordinary cases. This texture is not 

 seen so distinctly in the Mastodon's tooth as in the Elephant's, where it constitutes a thick 

 partition between the transverse ridges, and descends between them to cement together the 

 plates forming the body of the tooth. 



Fig. 2. — The mandibular tusk, belonging to the large skeleton, of its natural size. This 

 is one of the largest and most perfect yet discovered. The worn part of its point is very 

 conspicuous. 



Fig. 3. — The large, conical cavity of this tusk, which terminates in a narrow cylindrical 



tube. 



■ 

 Fig. 4. — The styloid process. 



PLATE XXI. 



■ ■ 



Fig. 1. — Anterior view of the atlas. (The dentata is seen behind it.) 

 Fig. 2. — Posterior view of the atlas. 



Fig. 3. — Lateral view of the atlas and dentata articulated with the cranium. 

 Fig. 4. — Underneath view of the same. 

 28 



