MAMMALIA. 11 



mals), but it is far from being so in the variety of its forms. In the 

 Slotbs, the Zygoma is straight and trigonal ; in the Armadillo and 

 Orycterope, twisted j in the Pangolin, thin, deep, and exteriorly concave ; 

 and in the Anteater, very small. South America is now, and has 

 always been, the natural home of this Order. 



Edentates began with the Miocene Period, and attained their maxi- 

 mum in the Pleistocene. Nearly all the fossil forms occur in the Pam- 

 pean formation of South America. The only extinct Edentate found in 

 Europe, and at the same time the most ancient, is the gigantic Pango- 

 lin — Macrotherium. The Monotreme and Anteater have not been dis- 

 covered fossil, unless the Myrmecophaga of Dr. Lund be a true deter- 

 mination. 



No. 23. Megatherium Cuvieri, Desmarest. 



Skeleton. This gigantic fossil was first made known to the scientific world 

 in 1789. It was discovered on the banks of the River Luxan, near the city of 

 Buenos Ayres, and was subsequently transmitted to Madrid, where, for half a cen- 

 tury, it excited the most lively speculations among all European naturalists, who 

 were so fortunate as to see it. The original bones, of which this specimen is a 

 copy, were found in the same Pampean deposit between the years 1831 and 1838, 

 and belong partly to the Hunterian Museum of the Royal College of Surgeons, 

 and partly to the British Museum. To give to the singular quadruped its proper 

 position in the Animal Kingdom, was for many years a problem in comparative 

 anatomy which the savans of Europe could not solve. Led astray by the huge 

 carapace of the Glyptodon, found near it, the majority called it a mammoth 

 Armadillo. Cuvier, who gave it its generic title, thought it combined the char- 

 acters of the Sloth, Anteater and Armadillo. The merit of throwing a flood of 

 light on the nature and structure of this most remarkable of all fossil mammals, 

 was reserved for the. celebrated English Geologist, Professor Owen. He conclu- 

 sively proves that the Megatherium was a " Ground Sloth," feeding on the foli- 

 age of trees which it unprooted by its great strength. 



The extreme length of the mounted skeleton is seventeen feet and nine 

 inches ; its height, from the pedestal to the top of the spinous process of the first 

 dorsal vertebra, is seven feet. No other fossil so exceeds its modern representa- 

 tive, as the lordly Megatherium surpasses the pigmy remnant of the Tardigrade 

 race ; for the largest living Sloth does not exceed two feet in length. One is 

 tempted to join the Spanish naturalist who objected to the place assigned to the 

 Megatherium, because " all the other Edentates could dance in his carcase." But 

 that there is the closest affinity between it and the diminutive arboreal Sloth, is 

 now undeniable. The number of the teeth, their deep insertion, equable breadth 

 and thickness, deeply excavated base, inner structure and unlimited growth, and 

 the absence of canines, are characters common to both. Both have the peculiar 

 zygomatic arch to the skull ; the alveoli of the jaAvs correspond in number, posi- 

 tion and relative depth. There is the same anomalous shortness of face ; a simi- 

 lar development of air cells surrounding the cerebral cavity ; the like scapula, 

 clavicle, ossified sternal ribs ; the identically expanded ilia ; the flattened femur ; 



