occurrence of the need for combined action, either habit attracts little attention. But so soon as co-operation begins to exercise its restraining and constraining influences, a very slight bias, due probably to individual organic structure, will suffice to determine the preference for one hand over the other, and so to originate the prevalent law of dexterity. The results shown by the ancient drawings of Europe’s cave-men perfectly accord with this. In that remote dawn every man did that which was right in his own eyes. Some handled their tools and drew with the left hand; a larger number used the right hand; but as yet no rule prevailed. In this, as in certain other respects, the arts and habits of that period belong to a chapter in the infancy of the race, when the law of dexterity, as well as other laws begot by habit, convenience, or mere prescriptive conventionality, had not yet found their place in that unwritten code to which a prompter obedience is rendered than to the most absolute of royal or imperial decrees. But we are not limited to the comparatively rare and exceptional examples of primitive dexterity which the works of the palæolithic carver and etcher supply for illustrations of the special habit now under consideration. The graceful proportions and delicate manipulation of many of the chipped implements of flint have, not unnaturally, excited both admiration and wonder, in view of the very limited resources of the worker in flint. But the process of the ancient arrow-maker is no lost art. It has been found in use among many barbarous races; and is still practised by some of the American Indian tribes, to whom the art has doubtless been transmitted through successive generations from remotest times. The modes of manufacture vary somewhat among different tribes; but they have been repeatedly witnessed and described by explorers who have watched the native arrow-maker at work; and his operations no longer present the difficulties which were long supposed to beset this “lost art” of prehistoric times. Among the rarer primitive implements are hammer-stones, oblong or rounded in shape, generally with cavities worked in two faces, so as to admit of their being conveniently held between the finger and thumb. Implements of this class have been repeatedly recovered from the French caves. An interesting example occurred among the objects embedded in the red cave-earth of Kents’s Hole, Devonshire; and others of different periods, usually quartzite pebbles or nodules of flint, have been found in many localities. Some of them were probably used in breaking the larger bones to extract the marrow, but the battered edges of others show their contact with harder material. Similar hammer-stones occur in the Danish peat-mosses, in the Swiss lake-dwellings, in sepulchral deposits, and are also included among the implements of modern savage art. They vary also in size, and were, no doubt, applied to diverse purposes.