i 4 o THE POPULAR SCIENCE MONTHLY. 



sometimes exceeds an inch, in the latter it is usually less than one-eighth 

 of that thickness. Note, also, the corresponding contrast in size. The 

 smallest living species is less than a foot in length, whereas the largest 

 known fossil form measured between twelve and thirteen feet in length, 

 or quite as much as the largest rhinoceros. In structure or make-up 

 these giants were sufficiently different from their living relatives to 

 characterize a distinct family, appropriately named by Huxley the Ho- 

 plop>horidce, or armor-bearers. Unlike the living armadillos, the back 

 and sides of the body were covered with an inflexible carapace, or 

 coat-of-mail, which, like the same in living forms, was made up of 

 numerous more or less nearly hexagonal tesserae or plates. In recent 

 forms the armor is divided into two parts : a forward part, covering the 

 scapular or region of the shoulder-blades, and a posterior, covering the 

 pelvic or region of the hips and flanks ; between the two a series of 

 mobile bands or zones of plates are interposed transversely, so as to 

 enable the animal to bend its covering upon itself, and thus envelop all 

 the soft parts, and thereby protect itself from enemies almost as effect- 

 ually as the hedgehog can with its spines. 1 The Hoplophoridce were 

 provided with an additional rigid, pear-shaped armor-plate or buckler 

 upon the under side of the body, hence they have also been called 

 Biloricata, or two-shielded, in contradistinction to the living Loricata 

 (armadillos), which are shielded only on the back. Head-shields cov- 

 ering the upper part of the head are characters common to both living 

 and fossil forms. The extinct species, with their carapace and plas- 

 tron, or belly-shield, resembled the snapping turtles in not having the 

 belly-shield to cover more than one-half of the area of the lower side of 

 the body left uncovered by the carapace of the back. The reason why 

 this belly-shield was smaller than the area it partially covered was to 

 allow free and unimpeded movement of the limbs. All that remains 

 of this rigid belly-shield in even the best-armored living species are 

 numerous separated plates, which do not interfere with that flexibility 

 of the walls of the abdomen which is necessary in bending the body 

 when the animal covers itself with its dorsal armor or carapace. 



Living species are mostly burrowing in habit. Whether the Ho- 

 plophoridm were burrowers cannot be affirmed, but it is extremely 

 doubtful; though, from the great resemblance of the fore-limbs and 

 claws to those of living species, it is likely that they were able, upon 

 occasion, to dig with great rapidity and dexterity. 



I have seen the tongue protruded nearly two inches with great 

 quickness by a young six-banded armadillo ; it is tapering and very 

 flexible, and is no doubt used to advantage in capturing insects which 



most of the materials which I have used in my studies and comparisons have been drawn. 

 From the wealth of materials at his command he has been enabled to present a fuller 

 account of the osteology of these creatures than any other hitherto published. The 

 memoirs of Owen, Lund, Nodot, Huxley and others, have also been consulted. 



1 See Brehm's " Thier-leben," vol. ii., p. 508, for an interesting account of this habit. 



