Passing by the many simple elements of decoration that by this unconscious process could be derived from such sources, let me give a single example by which it will be seen that not only elementary forms but even so highly constituted an ornament as the scroll may have been brought thus naturally into the realm of decorative art. The sea-shell has always been intimately associated with the arts that utilize clay and abounds in suggestions of embellishment. The _Busycon_ was almost universally employed as a vessel by the tribes of the Atlantic drainage of North America. Usually it was trimmed down and excavated until only about three-fourths of the outer wall of the shell remained. At one end was the long spike-like base which served as a handle, and at the other the flat conical apex, with its very pronounced spiral line or ridge expanding from the center to the circumference, as seen in Fig. 475 _a_. This vessel was often copied in clay, as many good examples now in our museums testify. The notable feature is that the shell has been copied literally, the spiral appearing in its proper place. A specimen is illustrated in Fig. 475 _b_ which, although simple and highly conventionalized, still retains the spiral figure. [Illustration: _a_ _b_ _c_ FIG. 476.--Possible derivation of the current scroll.] In another example we have four of the noded apexes placed about the rim of the vessel, as shown in Fig. 476_a_, the conception being that of four conch shells united in one vessel, the bases being turned inward and the apexes outward. Now it is only necessary to suppose the addition of the spiral lines, always associated with the nodes, to have the result shown in _b_, and by a still higher degree of convention we have the classic scroll ornament given in _c_. Of course, no such result as this could come about adventitiously, as successful combination calls for the exercise of judgment and taste; but the initiatory steps could be taken--the motive could enter art--without the conscious supervision of the human agent. +SUGGESTIONS BY FEATURES OF ARTIFICIAL OBJECTS.+ [Illustration: FIG. 477.--Ornament derived through the modification of handles.]