570 ZOOLOGY SECT. 



extremely modified dentition, the only functional teeth being 

 a single pair of large incisors in the middle in both upper and 

 lower jaws, with a single elongated trenchant pre-molar on each 

 side both above and below. 



Among the Edentata the majority of fossil, as of existing, forms 

 have been found in South America. But the family of the Cape 

 Ant-eaters, at the present day confined to South Africa, is proved, 

 by the discovery of remains in the Pliocene of the island of Samos 

 in the Eastern Mediterranean, to have formerly had a wider dis- 

 tribution. The American fossil Edentata, all of Pleistocene age, 

 comprise, in addition to extinct genera of Armadillos, some of 

 gigantic size, and one of Sloths, representatives of two extinct 

 families, the Glyptodontid.ee and the Megatlieriidce. The former 

 (Fig. 1163) are large Edentates resembling the Armadillos in 



FIG. 1163. Glyptodon clavipes. (After Owen.) 



the presence of a bony dermal carapace and a bony investment for 

 the tail ; but in the Glyptodontidse the carapace has no movable 

 rings, so that the animal could not roll itself up, and there is 

 usually a ventral bony shield or plastron, never present in the 

 Armadillos. Glyptodonts occur in North as well as in South 

 America. The Megatheriidse (Fig. 1164) are Edentates, mostly 

 of enormous size and massive build, which combine certain of the 

 features now characteristic of the Ant-eaters (Myrmecophagidse) 

 and the Sloths (Bradypodidse) respectively, the spinal column and 

 limbs allying them with the former, and the crania and the teeth 

 with the latter. 



The Cetacea are represented in the Tertiary (Eocene and 

 Miocene) of Europe, Egypt, and North America, by an extinct 

 sub-order the Archwoceti or Zeuglodonts, comprising only one 

 known gemisZeuglodon. Zeuglodon differs from existing Cetacea, 



