V. CLASS MAMMALIA, Linn 



Warm-blooded Amniota, Allantoidea with milk -glands. 

 Covered with hair. Quadrate transformed into the os 

 tympanicum ; mandible articulating with the squamosal. Two 

 occipital condyles. Ilio-sacral connexion preacetabular. With 

 cruro-tarsal joint. 



1. Sub-CLASS PKOTOTHEKIA, Huxley 



Oviparous. With a cloaca. Without chorion. 



Temporary marsupium, without nipples. 



Coracoids complete and articulating with the sternum. 



With large " epipubic or marsupial " bones. 



Mandible with (at least vestigial) an inner inverted angle. 



1. Order Allotheria, Marsh. Molars multitubercular. 

 Small mammals from the Triassic to the Eocene epoch. 



Tritylodon. Trias, S. Africa. 

 Bolodon. Jurassic, England. 

 Allodon. Jurassic, Wyoming. 

 Plagiaulax. Jurassic, England. 

 Microlestes. Ehaetic, Europe. 

 Polymastodon. Eocene, New Mexico. 



2. Order Monotremata, Geoffroy = Ornithodelphia, de 

 Blainville. Multi-tubercular molars are superseded by horny 

 coverings of the jaws. Australian region. 



Ornithorhynchus in Australia. 



Echidna and Proechidna. Australia and New Guinea ; 

 since the Plistocene of Australia. 



