EVOLUTION OF THE PROBOSCIDEA. 103 



maybe taken as (1) Ehphas maximus; (2) Tetrabelodon angustidens ; (3) Palceo- 

 mastodon beadnelli ; (4) Mcmtherinm lyonsi. The greatest gap is between the first 

 and second members of this series, but, as already pointed out, this is to a great 

 extent bridged over by a number of species, more especially from the Siwaliks ; 

 some of these species have been placed in an intermediate genus, Stegodon. 



The skull and mandible with the dentition are of course the most important portions 

 of the skeleton for the purpose in view, but some reference is made to one or two 

 other points. 



Figs. 2 and 3. — Mandible of Eleplms maximus, LlNN^EUS. Recent. India. 



Ehphas maximus, Linnaeus. {E. indicus, Cuvier.) 



The Skull (fig. I). — -The chief peculiarities of the skull of the elephant are due 

 to the great size of the molar teeth and their mode of succession, and also to the 

 weight of the tusks and trunk. The latter factor accounts for the enormous extension 

 of the occipital surface which is brought about by the development of the diploe to an 

 extent unparalleled in other mammals. The bones chiefly affected are the parietals 

 and squamosals, but most of the other bones of the skull present the same peculiarity to a 

 greater or less extent. The consequence is that the region usually occupied by the 

 lambdoidal crest is here expanded into a large mass of bone which forms attachment 



