48 FAUNA ANTIQUA SIVALENSIS. 



presenting the appearance of a reeded column or of a number of cords 

 pressed close together, is remarkable. This character is not present in 

 the corresponding young molars of Mastodon longirostris, PI. XL. fig. 6, 

 in which the enamel is irregularly wrinkled but never presents the 

 symmetrical fluting observed in the ' Crag ' Mastodon. This dif- 

 ference indeed is sufficient to distinguish the young teeth of the two 

 species. Discovered in the ' Crag ' at Postwick by Mr. Wigham, and 

 figured by Lyell, ' Manual of Elementary Geology,' 5th ed. 1855, 

 p. 166, fig. 133. 



Length of tooth, 2-9 in. Width anteriorly, 17 in. Width posteriorly, 1*8 in. 

 Width of grinding surface, l - 2 in. 



Figs. 8 and 8 a. — Mastodon Arvernensis. Last true molar, upper 

 jaw, right side, composed of five ridges with an anterior talon, and a 

 strong back talon. The crown is obscurely divided longitudinally by a 

 shallow cleft along its axis. Deep clefts or valleys intervene between 

 the ridges ; but the valleys, instead of being transverse, are interrupted 

 in the middle by one or more large accessory conical mammilla?, 

 interposed between the ridges and alternating with the outer and inner 

 divisions. This is the famous Whittingham tooth forming the frontis- 

 piece of Mr. W. Smith's ' Strata Identified,' and of which a woodcut 

 (reversed) is given in Owen's 'British Fossil Mammalia,' p. 276. 

 Length of tooth, 7" in. Width, 2-9 in. 



Figs. 9 and 9 a. — Mastodon Arvernensis. . Another specimen of last 

 true molar, upper jaw, left side. This is Captain Alexander's specimen 

 dredged up between Southwold and Easton, and of which there is a 

 cast in the Museum of the Geological Society. The specimen is very 

 black with a sandy matrix and no vertical pillaring. The crown con- 

 sists of five ridges and a heel ridge of four points. The anterior edge 

 is broken. The enamel is very thick. There are three sub-alternate 

 mammilla; in the first valley. The second and third ridges are very 

 closely approximated, with but one intermediate mammilla. The third 

 and fourth are wide apart with three mammillae in the valley. The 

 fourth and fifth have but one intermediate mammilla. 



Figs. 10 and 10 a. — Mastodon longirostris. Antepenultimate true 

 molar, upper jaw. From Eppelsheim. Cast in B.M. 

 Length, 4 - 5 in. Width, 2-5 in. 



Figs. 11 and 11 a. — Mastodon longirostris. Penultimate true molar 

 from Eppelsheim. Cast in B.M. 



Extreme length, 5"4 in. Width anteriorly, 3" in. Width posteriorly, 3*3 in. 



Figs. 12 and 12 a. — Mastodon longirostris. Last true molar, upper 

 jaw. Shows five ridges and a talon. The crown is broader, and the 

 mammillae thicker in proportion to their height, than in M. Arvernensis. 

 The ridges also are less elevated, and consist of a greater number of 

 coronal points. The valleys are either entirely open and transverse, or 

 interrupted only by an insignificant number of warty tubercles. From 

 Eppelsheim. Cast in B.M. 



Length, 9- in. Width, 3-8 in. 



Figs. 13 and 13 a. — Mastodon longirostris. Last true molar, upper 

 jaw, presentins; some characters as fig. 12. From Eppelsheim. Cast 

 in B.M. 



Length, 6-8 in. Width, 29 in. 



