ELEPHANTID.E. 53 



in the short mandibular symphysis, the alternate arrangement of 

 the columns of the cheek-teeth, the absence of premolars, and the 

 vertically-grooved enamel of the milk-molars. It differs, however, 

 by the slightly greater length of the mandibular symphysis, the 

 absence of a tendency to the development of a pentalophodont ridge- 

 formula, and the lesser complexity of the accessory tubercles of the 

 molars. The columns of the ridges are very tall, and incline 

 forwards in the lower teeth. In some adult molars the enamel is 

 grooved, while in others it is quite smooth. A fourth upper milk- 

 molar is figured in the accompanying woodcut (fig. 13) ; and full- 

 sized figures of m. 3 are given by Fritsch in the Jahrb. k. preuss. 

 geol. Land. 1884, pis. xxiii., xxiv. 



Mff. 13. 



Mastodon arvernensis. — The fourth left upper milk-molar; from the Norwich 

 Crag of Postwick, Norfolk. f. The lower border of the figure is the 

 inner border of the specimen. 



Hah. Europe. The species ranges in time from the Lower Plio- 

 cene of Montpellier to the Upper Pliocene of the Yal d'Arno and 

 the Xorwieh Crag ; and has also a wide distribution in space, having 

 been recorded from England, Prance 1 , Italy 2 , Germany, Croatia 3 , &c. 

 It should be observed that while the molars of the other species of 

 Mastodon occurring in the Eed Crag are usually much rolled, and 

 therefore probably derived from older strata, those of the present 

 species found in the same deposits are generally unaffected by rolling 

 action. 



1 See Lortet and Chantre, Arch. Mus. Lyon, vol. ii. p. 297 (1878). 



2 See Forsyth-Major, Quart. Journ. Geol. Soc. vol. xli. p. 2 (1885). 



3 Tacek, Abh. k.-k. geol. Eeichs. vol. vii. pt. 4, p. 30 (1877). 



