But, asks the gasping reader, what has this parade of mail-clad warriors and old battle-fields to do with so prosaic a theme as the exuviation of crabs? I must acknowledge that the question is a very natural one, for there appears at first sight no connection between the two subjects. The analogy will not, I believe, appear so forced when I mention my possession of a smaller, although hardly less singular armory, consisting of various coats of shelly mail, each of which, at one time or other, belonged to, and was worn by a living creature, and proved as effectual a protection in many fierce though bloodless combats as any casque or helmet worn by knight. Unlike the dummies of the Tower, my specimens are perfect, and give a complete representation, more truthful than any photograph, of the defunct originals, when armed by Nature _cap-a-pie_. In plain words, I own a curious collection of the cast-off shells of various crabs, which have from time to time been under my protection. From the fact that no museum in the kingdom contains a single _series_ of such objects, exhibiting the various stages of growth in any crustaceous animal, the reader will easily conceive the difficulty there must be in procuring them, and consequently the interest that attaches to the mysterious phenomenon of exuviation. Strange to say, the subject of this chapter is one of the least known in the whole range of natural history. The facts connected with the process are few, and far from well authenticated. This state of things appears the more extraordinary, when we remember the great facility with which specimens of crustacea may be found. For years past I have paid much attention to the elucidation of this subject, and during that period have had to submit to numberless mishaps and disappointments. For example, perhaps after watching a 'pet' day after day for months, anxiously expecting that exuviation would take place, in nine cases out of ten,--ay, in ninety-nine out of the hundred,--I would find that the process had been completed when I was asleep, or that the animal had died suddenly. In the latter case new specimens had to be procured, and the same watching process repeated, in most cases with the like unhappy results. I will now, however, endeavour as briefly as possible to make the reader acquainted with what has already been written upon exuviation, as far as I have been able to learn, up to the present time, interspersing the narrative with such notes as may seem necessary by way of illustration, and then proceed, in the words of Shakspeare, to lay down my own 'penny of observation.'