DESCRIPTION OF PLATE III. 



Mastodon (Tetralophodon) longirostris and Mastodon 

 (Trilophodon) angustidens. 



The figures in this Plate have been copied from those by- 

 Mr. Ford in Plate XL, vol. xiii., of the Quart. Journ. Geol. 

 Soe., with which the memoir on Mastodon was originally 

 illustrated. They are rather less than one-fourth (two- 

 ninths) of the natural size. 



Fig. 1. Mastodon {Tetralophodon) longirostris, Kaup, from Eppelsheim : 

 plan-view of the penultimate true molar from the left side of the 

 upper jaw. a, anterior talon ; t, posterior talon ; b, c, d, e, the 

 four principal ridges which .compose the crowns of the ' inter- 

 mediate molars' in the Tetralophodons. An irregular longi- 

 tudinal cleft along the middle divides the crown into an inner 

 and outer division. (See page 24.) 



Fig. 2. The same tooth seen in profile. From a cast in the Geological 

 Society's collection. 



Fig. 3. Mastodon {Trilophodon) angustidens, from the Dep. Gers, in the 

 Sub-Pyrenees: plan-view of the penultimate true molar from the 

 left side of the upper jaw, showing the worn discs of the three 

 principal ridges which compose the crowns of the ' intermediate 

 molars ' in the Trilophodons. a, anterior talon ; t, posterior 

 talon ; b, c, d, the three ridges. The longitudinal cleft is par- 

 tially worn out. (See page 22.) 



Fig. 4. The same tooth, seen in profile. From a specimen in the 

 collection of M. Lartet, For. Mem. G. S., Seissan, Gers. 



