MOERITHERIUM. 11 



quantities of trunks of fossil trees, embedded in the sands and 

 gravels of a great river. Probably both the animals and the 

 tree-trunks were swept away by floods, their remains piled up 

 in shallows and places where the current was slack, and buried 

 in the mud and sand carried down by the stream. 



The skull of the Moeritherium (see fig. 5) differs in no 



Skull and lower jaw of Moeritherium from the Middle Eocene of the Fayum, 

 Egypt. \ nat. size. 



ant.orb.j antorbital foramen ; c., canine ; e.v.oc., exoccipital ; fr., 

 frontal; *. 1-3 incisors; jit., jugal; m. 1-3, molars; mx., maxilla ; 

 fi., nasal; p.a., parietal; par., paroccipital ; pm. 2-4, premolars ; 

 p.nLT., premaxilla; pt., post-tympanic process of squamosal ; s.oc., supra- 

 occipital ; sq. squamosal. 



very marked manner from that of other primitive hoofed- 

 animals, and shows scarcely any trace of the peculiarities of 

 the skulls of the later Proboscidea. The most important 

 feature is the large nasal opening not quite at the end of the 

 snoutj the nasal bones being short ; this indicates that probably 

 there was already a short proboscis, something like that of the 

 tapir. Another interesting point is that some of the bones at 

 the back of the skull are thickened and contain air-chambers ; 

 in the later elephants this development of air-cells is carried to 

 such an extent that the whole form of the skull, particularly the 

 posterior portion, is entirely altered by it (see the broken 

 skull of the Indian elephant, stand G in Gallery). The reason 

 for this swelling of the bones is, that as the head becomes 

 heavier, owing in great part to the development of the trunk 



