94 THE NEOG^IC REALM. [CHAP.III. 



continuously without ever forming roots, and being mostly very 

 similar throughout the series. 



The mailed, or loricate edentates are represented by the two 

 families of the armadillos (Dasypodidce] and glypto- Armadillos 

 donts (Glyptodontida], the latter of which died out and Glypto - 

 at the close of the Plistocene or the commence- 

 ment of the Recent epoch, whereas the former is still abundant. 

 With the exception of the two species of pichiciagos (Chlamydo- 

 phorus] from Mendoza and Bolivia, in which a solid coat of mail 

 is confined to the hinder region of the body, the members of both 

 families have their bodies protected by a bony armour, while 

 their heads are guarded above by a shield of the same nature, 

 and their tails are enclosed in a tubular sheath. Covered exter- 

 nally with horny shields, like the shell of a tortoise, the carapaces 

 of these animals are formed of a number of small plates of bone, 

 either united everywhere by their edges into a continuous solid 

 armour, or in the middle region of the body overlapping one 

 another like the tiles on a roof. In the true armadillos (of which 

 the living Argentine forms are all comparatively small creatures, 

 although one Brazilian species reaches nearly a yard in length) the 

 carapace consists of a nearly solid buckler in front and behind, while 

 between the two are situated a variable number of movable over- 

 lapping bands, which in some instances admit of the body being 

 rolled up into the form of a ball. They have all long snouts, and 

 simple, subcylindrical teeth. The true existing armadillos may 

 be divided into the genera Dasypus, Xenurus, Priodon, Tolypeutes, 

 and Tatusia. The first of these, in which there are six or seven 

 movable bands to the carapace, is found throughout the Argentine 

 Tertiaries to the Santa Cruz beds, one of the fossil species from 

 the higher beds of the series having a skull of nearly a foot in 

 length, and thus vastly exceeding all its living congeners in size. 

 Tatusia, in which the carapace has from seven to nine movable 

 bands, does not appear to be known below the Pampean beds, 

 where it is represented by the large species of which the 

 external skeleton is shown in the figure on p. 93. A third genus, 

 Eutatus, which likewise comprises species of large size, and 

 ranges from the Pampean to the Santa Cruz beds, is distinguished 

 by having over thirty movable bands in the carapace. More 



