DIXOTHERim.i: 



435 



ami pandionis, from India ; M. americanus, obscurus, and productus, 

 North America; and J/, cordUlerum and humboldti, South America. 

 (2) Tetralophodont series — M. arvernensis, M. longirostris, from 

 Europe ; M. latidens, sivalensis, and perimensis, from India; M. miri- 

 flcus, from North America. Mastodon arvernensis and M. binijirndrU, 

 together with a trilophodont species, occur in the crag-deposits of 

 Norfolk and Suffolk. 



V< I in ill/ DlXOTHERIID.E. 



An extinct family distinguished from the JSlepkantidce by the whole 

 series of permanent cheek-teeth being in use at the same time, 



/// f = 22 : all 



Dinotherium. 1 - -Dentition of adult: i 

 present at the 

 same time, there 

 being no hori- 

 zontal succes- 

 sion, but the 

 premolars re- 

 placing milk- 

 teeth in the or- 

 dinary manner. 

 The presence or 

 absence of upper 

 incisors has not 

 yet been clearly 

 ascertained. 

 Lower incisors 



large, conical, descending, and slightly 

 curved backwards, implanted in a greatly 

 thickened and deflected beak or pro- 

 longation of the symphysis. In section 

 they do not show the decussating stria? 

 characteristic of Mastodons and Ele- 

 phants. Crowns of molars carrying strong 

 transverse, crenulated ridges, with deep 

 valleys between, much resembling the 

 loAver ones of the Tapirs. Ridge-formula 

 of the permanent molar series : 2, 2, 3, 

 2, 2. The three ridges of the first true 





hP 



Fig. 1S9. — Skull of Dinotherium, 

 giganteum, from the Lower Pliocene 

 of Eppelsheim, Hessen-Darmstailt. 

 (After Kaup.) p, 3, 4, premolars; 

 1, 2, 3, molars. 



molar are constant in both upper and 



lower jaws, although it is quite an anomalous character 



Proboscideans for 

 come behind it. 



among 



this molar to have more ridges than those which 

 The last milk-molar has also three ridges, the 



1 Kaup, Isis, vol. xxii. p. 401 (1829). 



