NATURAL HISTORY OF SELBORNE. 
419 
water. This may be a protection for him against the assaults of 
his enemies, though I cannot imagine that Nature anticipated 
the discovery and use of musket balls. 
If we look for scales in land animals, we shall find them more 
especially in the pangolin, the armadillo, and the tortoise. 
The pangolin's scales are very like, but yet differ from, fish- 
scales proper, inasmuch as they are not intended to be wetted. 
In the armadillo we find a series of scales of peculiar shape, 
not let into pockets as in the fish, but each connected with 
its neighbour by soft skin, so that the armadillo's skin may 
be said to be a series of oblong-headed nails (such as are used 
to tack on furniture fringes) fastened into a covering which 
forms the skin of the animal. The armadillo has to roll him- 
self into a ball as occasion requires ; — therefore the studs of 
his armour are so beautifully fitted as to size and shape that he 
can roll them up into a ball without the slightest appearance of 
a crease or wrinlde. 
In the case of tlie armadillo, who lives under a covering of 
horny, flexible skin, please to observe that his backbone, and 
all other bones, as well as his lungs, heart, and o':her viscera, 
are all undcmcath this flexible roof to his body. In the tortoise 
we find quite another arrangement. Take a tortoise-shell and 
boil it, and you will find that you can pick off the scales one by 
one, and underneath the scales is a tenter-house of solid-formed 
bone. This dome- shaped house is not composed of a con- 
tinuous mass of bone, as a tea-cup is made of a continuous 
plate of pottery, but rather of a series of small bones, all 
properly arched to suit the original curve, and jointed together 
in a most marvellous manner. It was not possible to rivet or 
bolt these plates together. Mortar could not be used to bind 
them together, as in the case of an arch made of bricks. What 
then must be done ? If the reader will examine for himself, he 
will find that the edges of each bone are deeply serrated, and 
that the serrations fit in such a workmanlike manner one into 
the otlier that an amount of solidity is gained which could not 
have been equalled if the whole dome had been cast in a solid 
piece. 
But how is the tortoise to live in his house ? Where are his 
ribs to go to ? Let us examine. In ordinary animals the back- 
bone forms an attachment for the ribs, and there are plenty of 
muscles, &c., outside the ribs. In the tortoise, the ribs them- 
selves are actually used to form part of the dome or roof By 
examining the inside of a tortoise-shell, the fact will at once 
become apparent. The ribs will be seen forming the girders of 
tliis wonderful roof, and they are connected together by moans 
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