THE LION AND HIS KIN 79 



digging up the large clams and other burrowing shell-fish 

 on which this animal mainly feeds. They are also 

 used as levers to drag the huge body out of the water 

 on to the ice. As fighting weapons they are formidable, 

 and the wounds they inflict are sometimes serious. The 

 polygamous habits of this huge creature may account for 

 the fact that they are so much larger in the males, 

 wherein they may attain a length of thirty inches, and 

 a weight of eight pounds a-piece. 



In connection with the monstrous tusks of the Sabre- 

 toothed Tiger there is a point which so far seems never to 

 have attracted the attention it deserves. And this 

 concerns two small flanges of bone which project from 

 the lower border of the end of the lower jaw. In them- 

 selves they are unimportant : they lie, it is to be noticed, 

 parallel with the points of the great upper teeth which 

 descend on either side of them. Their full significance 

 is not apparent till we turn to the skull of another 

 extinct animal of quite another type — the huge Dinoceros, 

 one of the Ungulates. This animal was also armed 

 with an enormous pair of tusks, which also, when the 

 mouth was closed, descended on either side of a flange. 

 In this case, however, the flange was developed to such 

 an extent that its free edge descended to the level of 

 the point of the tusk, thus affording it protection against 

 injury. The really striking feature of this curious down- 

 growth is not apparent till an attempt is made to explain 

 its presence. What determined its growth ? It seems 

 to furnish us with another of the many instances which 

 are to be found of the correlation of growth between 

 unrelated parts, for there is apparently no traceable 

 connection between the growth of this pair of teeth in 

 the upper jaw and the development of the flanges of the 



