52 FAUNA ANT1QUA SIVALENSIS. 



Figs. 3 and 3 a. — M. latidens. Upper molar (first true ?) witli four 

 ridges and back and front heel.- — B.M. 



Length, 4" in. ; width, 2'3 in. 



Figs. 4 and 4 a. — M. Perimensis. Fragment of upper molar showing 

 two ridges and part of a third. The valleys are transverse, but are 

 interrupted in the middle by an accessory lobule in front of and behind 

 each ridge, and the outer termination of each ridge is bounded by a 

 large mammilla, exactly as in Mastodon latidens. — B.M. 



Figs. 5 and 5 a. M. Perimensis. Fragment of lower jaw with 

 portion of true molar, presenting a similar arrangement of mammilla? 

 to that noted under fig. 4. 



Length of fragment of molar, 5'4 in. ; width, 3'2 in. 



Figs. 6 and 6 a. — Mastodon longirostris. Fragment of right lower 

 jaw of young calf showing the series of three milk molars in situ. The 

 third milk molar is nearly intact ; the four riclges of which it is com- 

 posed are seen to be transverse, compressed, and composed of a number 

 of little points ; the valleys are open, with the exception of a tubercle 

 in the first, and two or three minute tubercles in the last valley, which 

 in no way interrupt their transverse continuity. The back talon forms a 

 low transverse free ridgelet as in the Mastodon latidens of India. The 

 enamel is irregularly wrinkled, but exhibits no vertical fluting, as in 

 M. Arvemensis (Fee Plate XXXVI. fig. 7). The original specimen 

 from Eppelsheim was formerly in the Earl of Enniskillen's collection, 

 but is now in B.M. It is also figured by Kaup (' Oss Foss. de Darm- 

 stadt,' Plate XX. fig. 2.) 



Length of first tooth, 1-2 in. Width, - 9 in. Length of second tooth, 1*8 in. 

 Width, 1-5 in. Length of third tooth, 2'6 in. Width, 2-1 in. ■ 



Figs. 7 and 7 a. — Mastodon angustidens. Third ? milk molar upper 

 jaw, the crown consisting of three transverse ridges and an accessory 

 talon of two tubercles. A single tubercle juts out into each of the 

 hollows between the ridges alternately with the principal points, 

 accounting for the trefoil-shaped discs, which the worn teeth pre- 

 sent in this species, so different from the lozenge-shaped discs of M. 

 Ohioticus. This specimen is from Mr. Edward Charlesworth's collec- 

 tion, but there is no history as to its origin. — B.M. 

 Length of tooth, 2-8 in. Width, 1-6 in. 



Figs. 8 and 8 a. — M. angustidens. Antepenultimate or first true 

 molar, having the crown divided into three distinct ridges, with a small 

 back talon. 



Length, 46 in. Width, 2-6 in. 



Figs. 9 and 9 a. — M. angustidens. Penultimate molar of upper 

 jaw, consisting of three ridges and a talon appendage of two tubercles 

 behind. The two anterior ridges are affected by wear ; the last is 

 almost intact. The intervals, wide and deep, have only a single 

 mammilla connecting the ridges, about the middle. The crown is 

 very simple, each ridge consisting of two pairs of points. The tooth 

 has a strong impression in front, is narrow in front and widens behind. 

 The drawing is taken from a cast in B.M. The original specimen was 

 what Cuvier commenced his account of the species, and it is figured by 

 him in ' Divers Mastodontes,' p. 255, and Plate I. fig. 4. The dimen- 



