146 NATURAL HISTORY ESSAYS 



on the plains lie acres of yellowing grass which no 

 man will ever reap, while patches of clover^ blaze in 

 the afternoon sun. To these delights the palaeotheres 

 repair in open order, being joined as evening sets in 

 by herds of graceful xhiphodon, long- necked and 

 deer-eyed. The piping of snipe sounds thinly from 

 the reed beds : and noiselessly threading the mixed 

 groves of oak and elm, eucalyptus and mimosa, come 

 troops of bats, squeaking in shrill treble as they flit 

 moth-like over the darkening water. With the 

 last rays of sunset are heard the howls of the 

 hyaenodons, antedating by thousands of years the 

 doleful " laughter " emitted by their descendants of 

 to-day.^ 



Such then is a picture of a world vanished for 

 ever. Eocene, Miocene, Pliocene^ — each period is 

 imbued with an intense romantic charm for the 

 naturalist who can thus reconstruct for himself a 

 series of mind pictures. One may well ask whether 

 amid the highly evolved, greatly specialised beasts 

 of to-day there yet remain any forms which have 

 retained their original organisation unaltered throuo^h 

 the ages — living fossils, so to speak — documents of 

 Creation. Yes : the palaeotheres of Eocene times 

 are wonderfully perpetuated to-day in replicas true 

 almost to every detail of the skeleton, as one may 



1 Trifoliuni 2Kilacogoenm. 



2 There is reason to believe that the liyienodons (about a dozen 

 species in J^urope and America) were actually aquatic. They are, at any 

 rate, known to nave preyed upon water-tortoises. 



