328 EXTINCT PIG-LIKE ANIMALS CHAP. 



has a slight naked strip above the nostrils, as in the Sheep, but 

 there is no fissure of the upper lip. 



Extinct Families of Artiodactyla. 



The origin of the Artiodactyla is placed by Cope in the family 

 Pantolestidae, 1 allied to the genus Protogonodon of the Condy- 

 larthra. As, however, this family is represented by but a few 

 back teeth and a fragment of the hind-foot, it seems premature to 

 regard it as the necessary starting-point of the Bunodont and 

 Ruminant groups. 



Fam. Anthracotheriidae. This well-known and ancient 

 family consists of creatures of for the most part a Pig-like form, 

 with teeth approaching the selenodont shape, and a complete 

 dentition. The carpals, tarsals, metacarpals, and metatarsals are 

 all free. The toes are four (or five) to each foot, with the outer- 

 most beginning to be reduced. These of course are all generalised 

 and primitive characters, pointing nowhere in particular, except, of 

 course, to an Artiodactyle stock, on account of the teeth . and the 

 two predominating toes. 



The type genus of the family, Anthracotherium, is not, as its 

 name might seem to denote, a relic of the Carboniferous period ; 

 its remains were found in lignite, which may also show that it 

 was at least semi-aquatic in habit. Its form, however, must 

 have been Pig-like, so at least one would presume from the 

 elongated skull and shortish legs. There were species as great 

 as a Ehinoceros, and smaller forms. The genus began in the 

 Oligocene and continued down to the Pliocene. It is known 

 from Europe, Asia, and America. 



The skull is long with a prominent sagittal crest. The 

 facial part is also very long, and the orbits are not closed by a 

 bony ring. The premolars are simple teeth ; the molars dis- 

 tinctly bunodont with a tendency in one or two to the seleno- 

 dont condition. The canines are powerful, as are also the 

 incisors. The scapula has been specially compared with that 

 of the Camel. It has no acromion, which is usually though 

 not always absent in Ungulates. An ally of the present animal, 

 for instance, the Hippopotamus, has the acromion developed. 

 The radius and ulna, the tibia and fibula, are all fully developed. 



1 The name Triyonolestes has to be substituted for Pantolestes. 



