which nature spontaneously pays when there are no low feelings of envy or jealousy to interfere with her operations; and the reader may well believe that it was willingly rendered on this occasion to the genius of Agassiz. [Illustration: _PLATE IX._] The terminal flap of this gigantic crustacean was, as I have said, continuous. The creature, however, seems to have had contemporaries of the same family, whose construction in the divisions of the flap resembled more the lobsters of the present day; and the reader may see in the subjoined print the representation of a very characteristic fragment of an animal of this commoner type, from the Middle Sandstones of Forfarshire. (See Plate IX., fig. 1.) It is a terminal flap--one of several divisions--curiously fretted by scale-like markings, and bearing on its lower edge a fringe, cut into angular points, somewhat in the style of the Vandyke edgings of a ruff or the lacings of a dead-dress. It may be remarked, in passing, that our commoner lobsters bear, on the corresponding edge, fringes of strong, reddish-colored hair. The form altogether, from its wing-like appearance, its feathery markings, and its angular points, will suggest to the reader the origin of the name given it by the Forfarshire workmen. With another such flap spreading out in the contrary direction, and a periwigged head between them, we would have one of the sandstone cherubs of our country churchyards complete. There occur among the other organisms of Balruddery numerous ichthyodorulites--fin-spines, such as those to which I have called the attention of the reader in describing the thorny-finned fish of the lower formation. But the ichthyodorulites of Balruddery differ essentially from those of Caithness, Moray, and Cromarty. These last are described on both sides, in every instance, by either straight, or slightly curved lines; whereas one of the describing lines in a Balruddery variety is broken by projecting prickles, that resemble sharp, hooked teeth set in a jaw, or, rather, the entire ichthyodorulite resembles the sprig of a wild rose-bush, bearing its peculiar aquiline shaped thorns on one of its sides. Buckland, in his _Bridgewater Treatise_, and Lyell, in his _Elements_, refer to this peculiarity of structure in ichthyodorulites of the latter formations. The hooks are invariably ranged on the concave or posterior edge of the spine, and were employed, it is supposed, in elevating the fin. Another ichthyodorulite of the formation resembles, in the Gothic cast of its roddings, those of the _Diplacanthus_ of the Lower Old Red Sandstone described in pages 125 and 126 of the present volume, and figured in Plate VIII., fig. 2, except that it was proportionally stouter, and traversed at its base by lines running counter to the striæ that furrow it longitudinally. Of the other organisms of Balruddery I cannot pretend to speak with any degree of certainty. Some of them seem to have belonged to the