The amount of design exhibited in the scales of some of the more ancient ganoids,--design obvious enough to be clearly read,--is very extraordinary. A single scale of _Holoptychius Nobilissimus_,--fast locked up in its red sandstone rock,--laid by, as it were, for ever,--will be seen, if we but set ourselves to unravel its texture, to form such an instance of nice adaptation of means to an end as might of itself be sufficient to confound the atheist. Let me attempt placing one of these scales before the reader, in its character as a flat counter of bone, of a nearly circular form, an inch and a half in diameter, and an eighth-part of an inch in thickness; and then ask him to bethink himself of the various means by which he would impart to it the greatest possible degree of strength. The human skull consists of two tables of solid bone, an inner and an outer, with a spongy cellular substance interposed between them, termed the _diploe_; and such is the effect of this arrangement, that the blow which would fracture a continuous wall of bone has its force broken by the spongy intermediate layer, and merely injures the outer table, leaving not unfrequently the inner one, which more especially protects the brain, wholly unharmed. Now, such also was the arrangement in the scale of the _Holoptychius Nobilissimus_. It consisted of its two well-marked tables of solid bone, corresponding in their dermal character, the outer to the cuticle, the inner to the true skin, and the intermediate cellular layer to the _rete mucosum_; but bearing an unmistakable analogy also, as a mechanical contrivance, to the two plates and the _diploe_ of the human skull. To the strengthening principle of the two tables, however, there were two other principles added. Cromwell, when commissioning for a new helmet, his old one being, as he expresses it, "ill set," ordered his friend to send him a "_fluted pot_," _i.e._, a helmet ridged and furrowed on the surface, and suited to break, by its protuberant lines, the force of a blow, so that the vibrations of the stroke would reach the body of the metal deadened and flat. Now, the outer table of the scale of the Holoptychius was a "fluted pot." The alternate ridges and furrows which ornamented its surface served a purpose exactly similar with that of the flutes and fillets of Cromwell's helmet. The inner table was strengthened on a different but not less effective principle. The human stomach consists of three coats; and two of these, the outermost or peritoneal coat, and the middle or muscular coat, are so arranged, that the fibres of the one cross at nearly right angles those of the other. The violence which would tear the compact sides of this important organ along the fibres of the outer coat, would be checked by the transverse arrangement of the fibres of the middle coat, and _vice versa_. We find the cotton manufacturer weaving some of his stronger fabrics on a