MASTODON ARVERNENSIS. 35 



Milk molars. — Of the milk series it is not necessary on the 

 present occasion to enter on many details. I will refer only 

 to one or two characteristic specimens. The most perfect 

 and instructive yet met with was discovered in the Crag at 

 Postwick by Mr. Wigham, to whom I was indebted for the 

 means of comparing it carefully with a corresponding speci- 

 men of M. (Tetraloph.) longirostris from Eppelsheim, belonging 

 to the Earl of Enniskillen. It consists of the left upper jaw 

 of a calf Crag Mastodon, with the last milk molar beautifully 

 preserved in situ, and the remains of the empty alveolus of 

 the penultimate milk molar in front of it. The tooth is 

 stated, in Sir Charles Lyell's memoir on the ' Relative Ages 

 of the Tertiary Deposits of Norfolk,' l to be the ' second true 

 molar.' But it is really the last milk molar. He adds : — 

 ' This fragment was sufficiently perfect to enable Mr. Owen, 

 to whom I submitted it, to refer it to Mastodon longirostris, a 

 species also found at Eppelsheim.' The crown measures 3 

 inches long by 1*8 inch broad, and is composed of four ridges, 

 with a front and hind talon, and a well-pronounced basal 

 ' bourrelet.' The three anterior ridges are more or less worn, 

 especially along the inner division ; the last ridge is nearly 

 intact. Two views of this tooth, drawn with the utmost care 

 by an artist of well-known power and fidelity, Mr. George Ford, 

 are shown in the ' Fauna Antiqua Sivalensis,' PL XXXVI. 

 figs. 7 & 7 a. 2 The ridges are seen to be connected by one or 

 two stout conical mammillse, which occupy the middle of the 

 valleys, interrupting their transverse continuity, and alter- 

 nating with the divisions of the main ridges, in the manner 

 characteristic of the older or true molars previously described. 

 If these figures are compared with PL XL. figs. 6 &6 a 3 of the 

 same work, by the same artist, which represent Lord Ennis- 

 killen's very beautiful specimen of the young calf Mastodon 

 from Eppelsheim, the distinctive characters of the two species 

 will be found to be carried on throughout. The Eppelsheim 

 specimen is a little younger than the Crag fragment ; it shows 

 the series of three milk molars in situ. The third milk molar 

 is nearly intact ; the four ridges of which it is composed 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 nowise intercept their transverse continuity. 

 The back talon forms a low transverse free ridgelet, as in M. 

 (Tetralophodon) latidens of India ; while in M. (Tetralophodon) 

 Arvernensis the talon tubercles are huddled together and 

 accrete to the last ridge. 



1 Mag. of Nat. Hist. (1839), p. 318. 3 See vol. i. p. 472.— [Ed.] 



2 See vol. i. p. 467.— [En.] 



d 2 



