PALCONER MASTODON AND ELEPHANT. 259 



the agreement of the '' ridge -formula " of certain of the species with 

 that of "he existing African Elephant and other Loxodons. 3rd. In 

 the convex outline of each ridge in the transverse direction when 

 unworn, the central mammillte being the most elevated ; and in the 

 ahsenc,- of the longitudinal line of division along the middle of the 

 crown which is so characteristic of the Mastodons on the one hand, 

 and so generally absent in the Elephants on the other. 4th. Prom 

 the enormous quantity of laminated cement that fills up the valleys 

 in most of the species. 5th. In the pronounced arc of a circle de- 

 scribed by the molars as we trace them forwards in the jaws, as in 

 the Elephants, instead of the nearly horizontal line of protrusion ob- 

 servable in the most typical Mastodons, such as the species of North 

 America and of Simorre. 6th. In the obverse relation of the planes 

 of detrition of the opposed teeth during wear, the inner side of the 

 upper teeth, and the outer side of the lower, continuing higher in the 

 Stegodons, as in the typical Elephants, while the converse holds in 

 the Mastodons. 7th. From the absence or extreme rarity of pre- 

 molars in both jaws, and of mandibular tusks, neither of which, though 

 occurring among certain Mastodons, have been as yet detected among 

 the Stegodons. The aggregate weight of so many points of agree- 

 ment turns the balance strongly on the side of the Elephants. 



It is deserving of remark, that all the species of the Stegodon- 

 group at present known belong to the series' indicated in the pre- 

 ceding part of this paper, as being of the Dinotherian or Eurycoro- 

 nine * type, in that the crowns of the molars are broad, the ridges 

 uniformly transverse, and the valleys open, without being in the 

 least degree interrupted by outlying tubercles, as is seen in the 

 Hippopotamine or " Stenocoronine " type. Sir Proby Cautley and 

 myself have thought we could distinguish four species of Stegodon, 

 namely E. (Steg.) Cliftii, E. (Steg.) bombifrons, E. (Steg.) insignis, and 

 E. (Steg.) Ganesa ? The first, besides other distinctive marks, is at 

 once characterized by the broad distinction of the antepenultimate 

 and penultimate true molars being six-ridged, or hexaloj)liodont in 

 number, the last true molar conformably presenting an additional 

 ridge and " talon." The first of the " intermediate series," namely the 

 last milk-molar, has not yet been observed entire in situ in the jaw, 

 but I am prepared to expect that, when determined, it will present 

 five or six ridges. This species, the remains of which were discovered 

 by Mr. Crawford in Ava, constitutes the passage into the Mastodons ; 

 this is indicated both by the limited (?'. e. senary) number of ridges, 

 and by the circumstance that the crowns of the molars exhibit a 

 very obsolete or indistinct trace of a longitudinal bipartient cleft, as 

 in the Mastodons. Purther, in the only well-preserved palate-spe- 

 cimen at present known, the outer side of the upper molars is higher, 

 and the inner side lower and more worn, being another point of 



* It has been suggested to me that the contrasted terms of Dinotherian and 

 Hippopotamine types may mislead, through being supposed to imply a greater 

 amount both of affinity and of diiference than is inte^ided. I propose therefore 

 to substitute for the former " Eurycoronine " or broad-crowned type, and for the 

 latter "Stenocoronine" or narrow-crowned type, 



