A curious example illustrative of possible transformation by adventitious circumstances is found in the collection from the province of ancient Tusayan. A small vessel of sphynx-like appearance, possibly derived more or less remotely from a skin vessel, has a noticeable resemblance to some life form, Fig. 474, _a_. The fore-legs are represented by two large bosses, the wide-open mouth takes the place of the severed neck, and a handle connects the top of the rim with the back of the vessel. The handle being broken off and the vessel inverted, _b_, there is a decided change; we are struck by the resemblance to a frog or toad. The original legs, having dark concentric lines painted around them, look like large protruding eyes, and the mouth gapes in the most realistic manner, while the two short broken ends of the handle resemble legs and serve to support the vessel in an upright position, completing the illusion. The fetich-hunting Pueblo Indian, picking up this little vessel in its mutilated condition, would probably at once give to it the sacred character of the water animal which it resembles, and it might readily transmit its peculiarities of form to other generations of vessels. It is not necessary in this study to refer at length to the influence of metallic vessels upon ceramic forms. They do not usually appear until the ceramic art is far advanced and often receive a heritage of shape from earthen forms. Afterwards, when the inherent qualities of the metal have stamped their individuality upon utensils, the debt is paid back to clay with interest, as will be seen by reference to later forms in many parts of the world. +MODIFICATION BY INTENTION.+ _To enhance usefulness._--There can be no doubt that the desire upon the part of the archaic potter to increase the usefulness and convenience of his utensils has been an important agent in the modification of form. The earliest vessels employed were often clumsy and difficult to handle. The favorite conch shell would hold water for him who wished to drink, but the breaking away of spines and the extraction of the interior whorl improved it immeasurably. The clumsy mortar of stone, with its thick walls and great weight, served a useful purpose, but it needed a very little intelligent thought to show that thin walls and neatly-trimmed margins were much preferable. Vessels of clay, aside from the forms imposed upon, them by their antecedents and associates, would necessarily be subject to changes suggested by the growing needs of man. These would be worked out with ever-increasing ease by his unfolding genius for invention. Further investigation of this phase of development would carry me beyond the limits set for this paper.