216 EDENTATES. 
is so great as to allow of the animal rolling itself into a complete ball. One 
peculiar genus of extinct armadillo differs from all living forms in that the whole 
body-shield was composed of these movable plates. Usually a certain number of 
hairs protrude between the bony plates of the armour; and in some cases these are 
so numerous as almost to conceal the armour, and give the appearance of a furry 
animal. Each bony plate is sculptured, varying in pattern in the different 
genera; and it 1s overlain by a horny shield, developed in the cuticle or epidermis ; 
the bones themselves belonging to the true skin. The upper surface of the head 
is also protected by an armour of similar structure; and the tail is usually en- 
circled by a series of bony rings. The limbs are likewise protected externally by 
a number of bony plates embedded in the skin, which do not, however, articulate 
together by their edges. The fore-feet are provided with very powerful curved 
claws adapted for dig- 
ging, and varying in 
number from five to 
three ; while in the hind- 
feet the claws are of 
smaller size, and invari- 
ably five in number. 
The numerous teeth are 
small and simple, looking 
like small pegs fixed in the jaws; and in one genus the anterior teeth are preceded 
by a deciduous milk series. The tongue is considerably elongated, although to a 
less extent than in the ant-eaters. 
The elongated skull is characterised by the full development of the zygomatic 
or cheek arch; and the collar-bones are complete. In the hind-lmbs the 
bones of the second segment—tibia and fibula—differ from those of the other 
existing members of the order by being united together at their lower extremities. 
Another peculiarity is that a variable number of the vertebra in the middle of the 
neck are likewise immovably welded together. In the development of additional 
facets for mutual articulation, the vertebrae of the loins of the armadillos resemble 
those of the ant-eaters. The ribs are of considerable width; and the upper lateral 
processes of the back are specially developed for the support of the carapace. 
Most of the species are of comparatively small size; the largest living one not 
exceeding 3 feet in length, exclusive of the tail; but in the Pleistocene of Argentina 
there occurs the gigantic Dasypotheriwm, with a skull about a foot in length. In 
the Argentine pampas the armadillos are as a rule diurnal, in other districts many 
appear to be crepuscular or nocturnal. The majority are mainly or exclusively 
insectivorous, but one species consumes not only flesh, but vegetable substances. 
In disposition these Edentates are mostly harmless and inoffensive little creatures ; 
a Gaucho remarking to Mr. Darwin, as he sharpened his knife on the back of one, 
“they are so quiet (son tan mansos”). All of them burrow in the ground ; and so 
rapid is the act of burrowing, that, as the writer has witnessed, if a horseman sees 
one of these animals, it is almost necessary for him to tumble off his horse in order 
to capture it before it disappears in the soft soil of the pampas. They run with 
considerable speed, some of the species merely touching the ground with the tips of 

SKELETON OF ARMADILLO. 
