The animals of this family are commonly called Armadillos, a word of Spanish origin, having reference to their armour-like covering. The existing species are all of small or moderate size. They are mostly, though not universally, nocturnal in their habits, and are all omnivorous, feeding on roots, insects, worms, reptiles, and carrion. Armadillos are harmless and inoffensive creatures, offering no resistance when caught, their principal means of escape from their enemies being the extraordinary rapidity with which they can burrow in the ground, and the tenacity with which they retain their hold in their subterranean retreats. Notwithstanding the shortness of their limbs they can run with great rapidity. Most of the species are esteemed good eating by the natives of the countries in which they live. They are all inhabitants of the open plains or the forests of the tropical and temperate parts of South America, with the exception of one species (_Tatusia novemcincta_), which ranges as far north as Texas. Of the existing genera, _Chlamydophorus_ stands apart from the rest in the formation of its external covering; but in all other respects _Tatusia_ is the most aberrant form, exhibiting a peculiar type of structure of the fore feet, which in all the others show modifications, though in very varying degrees, of a single and different type. The reproductive organs of the _Dasypodidæ_ differ from those of the Sloths and Armadillos in the presence of a largely developed copulating organ in the male, and of a simple vagina of corresponding length in the female. The testes are still abdominal, although not in the same position; and the penis still wants both the glans and bulb. The uterus is nearly or quite as simple as in the Sloths and Anteaters; and there is no reason to believe that the placentation is essentially different from that obtaining in the other groups. Subfamily =Chlamydophorinæ=.—In most anatomical characters, especially the structure of the fore foot, this little group resembles the _Dasypodinæ_; but it differs remarkably from all other known Armadillos, living or extinct, in the peculiar modification of the dermal armour.