12 



KNOWLEDGE & SCIENTIFIC NEWS. 



Tep.., 1904. 



The surviving upper incisors are rather large tusks, and 

 have lost all the enamel except a narrow band on one 

 face — exactly like the front teeth of a gnawing animal 

 (Rodent). The lower incisors are at the end of the chin 

 far in front of the upper tusks, and they are still more 

 like the incisors of a rodent (fig. 2a). They have a band 

 of enamel on their lower face, and they are worn to a 

 chisel-shaped edge by some opposing hard substance — 



ones take their place ; and these teeth exhibit greater 

 complication than before, the posterior molar at least bear- 

 ing four cross-ridges, with a rudiment of a fifth ridge 



(fig- 3^)- 



There is not much doubt that, with so remarkably 



elongated a head, Tdrahelodon would be able to browse on 

 or near the ground, notwithstanding the length of its legs 

 and the shortness of its neck. However, the shape of the 

 skull shows that, even if the animal did not 

 need a proboscis, the arrangement of the 

 soft parts of its face and nose must have 

 closely resembled this prehensile organ in 

 a modern elephant. The outline of the head 

 is, indeed, fancifully given in the accom- 

 panying fig. 6 ; and from this it is evident 

 that the only hindrance to the use of the 

 snout as a typical proboscis is the immensely 

 elongated bony chin which underlies it. 



Towards the close of the Miocene period 

 many of the "mastodons," as these animals 



perhaps a pad on the palate. The grinding teetli of the 

 upper jaw are as numerous as in Mocritherium, and those 

 of the lower jaw are only reduced by the loss of another 

 front pre-molar. The three molars, however, are rela- 

 tively larger and more complicated than in the earlier 

 genus, each bearing three cross-ridges, the hindermost 

 also with a rudimentary fourth ridge (fig. 2b). 



Fig. 2.—Telrabelodon angustidens ; left side-view of skull, upper view of mandible (Aj and diagrammatic section of last molar 



tooth (B). — Middle Miocene; Europe. 



The elephant-like quadrupeds continued to live in 

 Africa from the Eocene period to the present day, but, 

 probably through some re-arrangement of land and sea, 

 they also wandered into Europe in the early part of the 

 Miocene period, and soon afterwards penetrated even to 

 the extreme eastern limits of Asia. The European and 

 Indian members of the race during these later periods are 

 indeed better known than those from Africa itself, and 

 they must be referred to for information concerning the 

 Miocene and Pliocene developments. 



In the Middle Miocene, as shown by Tdrahdodoii 

 anguslidens (fig. 3), the hinder part of the skull becomes 

 short and deep, the upper tusks and their sockets are 



are generally termed, actually lost their bony chin by 

 the shortening of the lower jaw. The soft snout being 

 then destitute of support of any kind, must have begun 

 to droop downwards ; and there is thus no difficulty in 

 understanding how it eventually became the essential 

 feature of the modern elephants. 



Some of the short-chinned species which form the genus 



longer than in any earlier genus, and the spout-like 

 mandibular symphysis, with chisel-shaped incisors at the 

 tip, is more elongated than ever (fig. 3A). The grinding 

 teeth are now so large that not more than two or three on 

 each side of the jaw are in use at any one time, the front 

 grinders being pushed out of the mouth as the hinder 



fYW\) 



Fig. .?b. 



