The Armadillos of this genus have the power of rolling themselves up into a perfect ball, the shield on the top of the head and the tuberculated dorsal surface of the tail exactly fitting into and filling up the apertures left by the notches at either end of the carapace. This appears to be their usual means of defence when frightened or surprised, as they do not burrow like the other species. They run very quickly, with a very peculiar gait, only the tips of the claws of the fore feet touching the ground. Three species are described:—_T. tricinctus_, the Apar; _T. conurus_, the Matico; and _T. muriei_. Remains apparently referable to _T. conurus_ are of not uncommon occurrence in the Brazilian cavern-deposits. Subfamily =Tatusiinæ=.—This group contains but one genus, _Tatusia_.[108] Teeth ⁸⁄₈ or ⁷⁄₇, very small subcylindrical. The first and second subcompressed, the last considerably smaller than the others. They present the remarkable peculiarity (elsewhere found among Edentates, so far as is yet known, only in _Orycteropus_) of all being, with the exception of the last, preceded by two-rooted milk teeth, which are not changed until the animal has nearly attained its full size. Vertebræ: C 7, D 9-11, L 5, S 8, C 20-27. Head narrow, with a long, narrow, subcylindrical, obliquely-truncated snout; pterygoids meeting in the middle line below the nasal passage. Ears rather large, ovate, and erect, placed close together on the occiput. Carapace with seven to nine distinct movable bands; sculpture on scutes consisting of pits arranged in a V-shape. Body generally elongated and narrow. Tail moderate or long, gradually tapering; its dermal scutes forming very distinct rings for the greater part of its length. Fore feet with four visible toes, and a concealed clawless rudiment of the fifth. Claws all long, slightly curved, and very slender, the third and fourth subequal and alike, the first and fourth much shorter. Hind feet with five toes, all armed with strong, slightly curved, conical, obtusely-pointed nails. The third longest, then the second and fourth; the first and fifth much shorter than the others. [Illustration: FIG. 67.—The Peba Armadillo (_Tatusia novemcincta_).] This genus differs from all the other Armadillos in having a pair of inguinal mammæ, in addition to the usual pectoral pair, and in producing a large number (four to ten) of young at a birth, all the others having usually but one or two. The Peba Armadillo, _T. novemcincta_ (Fig. 67), is a well-known species, having an extensive range from Texas to Paraguay. It is replaced in the more southern regions of South America by a smaller species, with shorter tail, the Mulita (_T. hybrida_), so called from the resemblance of its head and ears to those of a mule. _T. kappleri_ is a large species from Surinam.