MAMMALIA. 33 



with long flattened nails, similar to those of the Elephant. The teeth, num- 

 bering eight on each side of each jaw, are sculptured laterally by two wide 

 and deep channels, which divide the grinding surface into three portions. 

 The generic name is derived from the fluting of the molars. The lower 

 jaw is of singular shape, its angle being elevated to a level with the grinding 

 surface of the teeth. But the most remarkable characteristic of the skull is 

 the long, strong process descending from the base of the zygomatic process. 

 The animal measured from snout to the end of the tail, following the curve 

 of the back, eleven feet; the tesselated trunk armor being six feet eight inches 

 in length and nine feet across. The Glyptodons do not appear to have emi- 

 grated from the central regions of South America, but formed a local fauna 

 of the highest interest, which is now only faintly represented by the living 

 Armadillos. The carapace of these edentates' probably weighed more than a 

 thousand pounds. The original was found in 1846, near Montevideo, on the 

 banks of the Luxan. It was presented by order of the Dictator Rosas to 

 Vice-Admiral Dupotet, who gave it to the Museum of his native city — 

 Dijon, France, where it is still preserved. 



ORDER MARSUPIALIA. 



(NON-PLACENTAL MaMMALs). 



The Marsupials possess a peculiar feature which places them 

 lowest in the mammalian series. This feature is the premature 

 production of their young, which are matured in a pouch, sup- 

 ported by two peculiar bones attached to the pubis. These char- 

 acteristic bones are found in all marsupials — male as well as 

 female, except the Thylacinus. The order presents a remarkable 

 diversity of structure, there being herbivorous, carnivorous and 

 insectivorous species, suggesting many of the higher orders of 

 mammals. In the herbivorous species, the canines are usually 

 wanting. With the exception of the opossums {Didelphidm), 

 of which twenty species are found in North and South America, 

 mai-supials are now confined to Australia, Tasmania, and New 

 Guinea, and some adjacent islands. 



Marsupials were the first of mammals — the Mierolestes having 

 been discovered between the Lias and Keuper Sandstone near 

 Stuttgardt, while the Dromaiheritun was found in the Upper 

 Triassic coal-field of North Carolina. They are also found in 

 the Jurassic of both hemisphei-es. None have been found in 

 cretaceous strata, but they again occur in the Eocene, and then 

 disappear from Europe. The American Eocene forms, as well as 

 the Post-tertiary ones from the caves of South Ainerica, are 

 related to the Opossums. 



