198 



ARMADILLO. 



in others, four on the anterior ones, and five on the 

 posterior. The nails upon these are large and strong, 

 round on their upper surfaces, hollow on their under, 

 and admirably adapted for digging. It would not 

 be altogether consistent with the nature of a popular 

 work to enter minutely into anatomical details ; but 

 we may mention generally that the system of appa- 

 ratus by which the feet and toes of* the armadillos 

 are moved is peculiar, very powerful, and fitted alike 

 for vigorous and continued action. 



One of the most singular indications in the bones, 

 and consequently in the parts which these bones sup- 

 port, is a resemblance to birds. This resemblance 

 appears in the bones of the lower part of the body 

 only, because the armour on the upper part, and 

 those adaptations of the vertebrae and other bones 

 which have been mentioned, preclude any resem- 

 blance in that part. The resemblance is, also, but 

 slight, not so great as in the Ornithorhynchus or 

 Echidna of New Holland ; the one of which is an 

 aquatic animal, and burrows in the ooze and mud, 

 the other a land animal, and burrows in the earth ; 

 but still it shows a deviation from the ordinary 

 structure of mammalia, which breathe by expansions 

 and contractions of the chest. In the armadillos there 

 is a rudiment of a furcal bone, or " merry-thought;" 

 and the sternal portions of the ribs are completely 

 ossified. To compensate for this want of mobility 

 in the parietes, or walls of the thorax, and still give 

 the animal freedom in breathing, that cavity is capa- 

 cious iu its dimensions, and each lung of the animal 

 consists of three lobes. These circumstances com- 

 pensate for the want of a flexible chest, as in the 

 mammalia proper, and also for that of air cells, as in 

 birds. The bones of the pelvis also indicate a slight 

 approach to the structure of the winged tribes. The 

 bones of the pubis do not remain wholly detached 

 from each other, as in these, or in the great ant-eater, 

 or the Chlamyphoruf, an animal which has some 

 external resemblance to the armadillos (see CntAMY- 

 PHORUS); but they are united by symphosis at their 

 points only. In the remainder of the pelvis the 

 resemblance to birds is still greater; the sacrum is 

 very broad posteriorly, and the angles of it are com- 

 pletely anchylosed to the spines of the ischia, so that 

 the walls of this cavity are, like those of the chest, in 

 in a very great degree inflexible. 



It may seem singular, to those who are not in the 

 habit of tracing analogies in natural history, that ani- 

 mals which live great part of their time under the 

 earth, and have coverings much more solid than the 

 other mammalia, should be the ones which have most 

 resemblance to those animals, the majority of which 

 spend great part of their time in the air ; but it is 

 nevertheless true ; and, as has been already hinted, 

 they, in some parts of their skeleton, also bear some 

 resemblance to the whales, which spend the greater 

 part of their time in the water. These analogies in 

 structure must be attended with analogies of use, 

 though it is more difficult to understand these, inas- 

 much as it is not always possible so to analyse the 

 functions of an animal, as to show how they accord 

 with the different parts of its organisation. The 

 stiffness given to the neck by the anchylosis of its 

 central vertebrae, and to the whole spinal column, by 

 the armour, and the bearing of the processes of the 

 vertebrae against that, evidently enables the armadillo 

 to push forward into the earth, so as to keep itself 

 advanced to the full action of the claws in burrowing 



downwards in an oblique manner, which it does with 

 very great rapidity ; so fast indeed as almost to elude 

 pursuit ; for as it gets the body buried, it takes so 

 powerful a hold of the earth, that" the tail may be 

 pulled away without bringing out the animal. In 

 these cases it is probable that it holds on with the 

 whole body, and not merely with the feet. While 

 digging, the legs are not stretched, so that when it 

 raises itself upon these, the body is brought into firm 

 contact with the upper part of the burrow ; and the 

 armour holds like a screw by means of its transverse 

 prominences. The echidna shows the same facility 

 in burrowing, and the same power of adhering to 

 the earth ; and it probably is assisted in holding on 

 by its spinous covering. 



From the direction in which it descends, which, 

 according to D'Azzara, (whose statements being 

 founded on personal observations are worthy of 

 implicit confidence), is at an angle of forty-five 

 degrees, or exactly midway between the horizontal 

 and the perpendicular directions, it is easy to see the 

 advantages which the armadillo derives from the firm 

 and bird-like structure of the chest. This steep 

 slope of the burrow continues for about three or four 

 feet, or double the length of the average species. It 

 is much steeper than the slope at which loose earth 

 stands : and, therefore, what the animal pushes up- 

 ward by its action in digging, must have a constant 

 tendency to descend upon it by the force of gravita- 

 tion ; and thus with the pushing of the earth upwards, 

 and the resistance of this tendency to fall down again, 

 there must be considerable pressure on the body of 

 the animal. One can also see the advantage of the 

 armour, and even of the enlarged pelvis in the per- 

 formance of this operation. The armour bears 

 against the roof and sides of the burrow, nearly as a 

 solid piece, the whole extent of the body of the ani- 

 mal ; and its transverse irregularities take such a hold 

 as to form a powerful fulcrum for the digging mem- 

 bers, while the breadth of the pelvis prevents the 

 mould from rolling back at the sides, and pressing 

 upon and hampering the anterior part of the animal, 

 the part which has the hardest task to perform. 



But the resemblance to birds is not confined to the 

 bones of the under part, it can be traced in the diges- 

 tive organs. Most of the species, if not all of them, 

 are very miscellaneous in their feeding. Tuberous 

 roots, and other farinaceous vegetable substances, 

 worms, insects, carrion, all things, in short, that consti- 

 tute what may be called an omnivorous, or, at all 

 events, a very miscellaneous feeder, are greedily 

 sought after by armadilloes. Their teeth are not at all 

 adapted for mastication, as whatever may be their num- 

 ber and their situation in the mouth, they are slender, 

 stand apart from each other, and in the two jaws 

 fall into the intervals of each other when the jaws are 

 closed, so that they do not cut tooth against tooth, 

 in such a way as that they can either cut or bruise. 

 The month is thus an instrument for the prehension 

 or taking of the food only, and can assist little, if at 

 all, in preparing it for the stomach. The stomach is 

 partly of a gizzard structure, that is, its coats are 

 thick and muscular toward the pyloric extremity, or 

 that to which the intestinal canal is attached. This 

 structure evidently answers two purposes : first, it 

 prevents the food from getting into the intestines 

 before it is properly comminuted ; and secondly, 

 the action of the muscular coat assists in the process 

 of comminution, in the same manner, though pro- 



