The rougher and more homely oyster-shell has also enjoyed the favor of the mound-building tribes, and has probably served many useful purposes, such as would only be suggested to peoples unacquainted with the use of metal. Many species of the _Fissurella_ and _Dentalium_ shells were in common use, advantage being taken of the natural perforations for stringing, the latter being quite extensively used for money on the Pacific slope. In Fig. 2, Plate XXI, a cut is given of a _Mytilus_ shell paint-cup from an ancient Peruvian grave. It is copied from Plate 83 of the Necropolis of Ancon.[3] It is represented as still containing red paint, probably cinnabar. A great variety of the larger univalve sea-shells were used in the unaltered state, the _Busycons_ probably taking the most important place, species of the _Strombus_, the _Cassis_, the _Nautilus_ and _Fasciolaria_ following in about the order named. The _Busycon perversum_ has been more extensively used than any other shell, and consequently its distribution in one form or other is very wide. It is obtained along the Atlantic and Gulf coasts from Massachusetts to Mexico, and within the United States it is artificially distributed over the greater part of the Atlantic slope. The uses to which this shell has been put by the ancient Americans are so numerous and varied that I shall not attempt to enumerate them here. They are, however, pretty thoroughly brought out in the subsequent pages of this paper. From the employment of shells in their complete state their modification for convenience is but a slight step, and when once suggested is easily accomplished--holes are bored, handles are carved or added, margins are ground down, useless parts are broken away, and surfaces are polished. The columellæ are removed from the large univalves, and the parts used for a great variety of purposes. The mechanical devices employed have been very simple, such as flint implements for cutting, and rough stones for breaking and grinding. Hand-drills were at first used for perforating; but later mechanically revolving drills were devised. [Illustration: PL. XXI--SHELL VESSELS. 1. From a plate in De Bry. 2. From a Peruvian grave. 3. _Pecten_, California grave. (1/1) 4. _Haliotis_, California grave. (3/4)] VESSELS. I shall not attempt to take up the various classes of objects in shell in the order of their development, as it would be hard to say whether food utensils, weapons, or ornaments were first used. It is also difficult to distinguish weapons proper from implements employed in the arts, such as celts, knives, hammers, etc., as it is probable they were all variously used according to the needs of their possessors.