Two or more illustrations may be combined to form one plate in order to permit easy and close comparison as well as for economy, for if a particular illustration is too small to make a full plate and is not suitable for enlargement other illustrations that are closely related to it may be put on the same plate. The size of the printed page as given in the table on page 11 will determine the size of the plate. In making up plates composed of a number of figures the author should endeavor to group related figures together and at the same time to observe proper regard for artistic effect, but as figures vary in size and shape a grouping according to relations may not be possible in some plates. If related figures can not be kept together the larger and darker figures should be placed in the lower part of the plate and the smaller and lighter above. If a plate consists of one large figure and several smaller ones the large figure should be placed below and the smaller figures above. A number designating a figure should be placed immediately below the figure, and a series of such numbers should preferably begin with 1 in the upper left corner and continue consecutively across and down through the plate. This arrangement is not always possible, however, on account of variations in the size of figures. As drawings of fossils or other specimens are prepared separately and grouped into plates, and as most paleontologists make up their own plates, each in his own way, there is naturally great dissimilarity in methods and in results. Ordinary white or light-gray cardboard should be used, and the figures that are to make up a plate should be arranged as stated above but not securely pasted until the grouping is satisfactory. In trimming each drawing or photograph the author should be careful to leave room at its lower edge for the number. Small drawings or photographs, such as paleontologists use, when pasted on bristol board or other board faced with tough paper are difficult or impossible to remove without injury if they have to be remounted; figures pasted on ordinary white or gray cardboard can be removed without difficulty. Each plate should be made up in a size to fit the volume or in its correct proportion to a page in the volume in which it is to be used (see table on p. 11), and each figure should be properly oriented--that is, all vertical lines, or the vertical axis of each specimen, should be parallel with the sides of the plate. When the figures are being mounted care should be taken that the mucilage or paste does not exude under pressure and cover any part of the drawing or photograph. The same attention should be given to pasting on numbers. Inattention to these details may produce results that will affect the reproduction of the plates.