OLIGOCENE PERIOD 149 



whilst some had so far advanced as to be real hedgehogs, 

 although they differed in some minor points from modern 

 forms (PalcBoerinaceus). Creatures almost shrews, and also 

 completed shrews, were now abroad (Amphisorex, Sorex), 

 and in some cases probably were adopting aquatic habits. 



Thus underground, on the ground, and probably in the 

 water was this ancient line of life grappling with the problems 

 of existence. 



It is supposed by many that from the ancestral stock of primates 

 these various insectivores certain forms must have diverged, 

 in times prior to the Eocene, and given rise to the Order of 

 Primates. As early mammal life was so much intermixed, 

 the question of the origin of particular groups is beset with 

 difficulties ; but it is certain that some of the Eocene 

 lemurs or half-monkeys held strong affinities with the insect- 

 eaters. 



The Primate Order was represented in the earliest Eocene 

 by some vaguely defined lemur-like animals ; and as the 

 Period advanced some animals more closely resembling 

 lemurs made their appearance. In OUgocene times animals 

 were in being that, in regard to the number of teeth and the 

 shape of the skull, still more resembled lemurs as now known 

 (Necrolemur). 



Certain of the Eocene lemuroids seem to have been develop- 

 ing in the direction of apes (Adapts) ; and animals identical 

 in form with these were living in Oligocene times ; but no 

 remains of more advanced primates have been discovered. 

 Animals which have been referred to the apes were living in 

 European forests ; but they seem to have had quite as close 

 affinities with pigs as with apes, and they were probably 

 a disappearing race (Ceho cheer us). Some interesting primates 

 were living in Africa in late Eocene times, but their de- 

 scendants of the Oligocene have not yet been brought' to 

 light. 



Before leaving the mammals notice must be taken of whales 

 certain creatures whose far-back ancestors had quitted the 

 land for a seafaring life. Before the close of the Eocene 

 some whale-like forms, known as Zeuglodonts, were exploring 

 the seas in many parts of the world. Descendants of these 



