If undisturbed, the process would result eventually in changing the button to a round or nearly round pearl, but should the pearl be taken from the fish before the metamorphosis is completed, a depression, or pit, would mar its contour. When borers intrude through the shell, the presentation is at once covered with nacre, and successive deposits are built up around it resulting in the nacreous wart known as a baroque. The rounding action of the mollusk is clearly shown in these excrescences, as the borer is not simply covered and levelled with the shell, but the slight elevation above the level of the lining receives a continuity of concentric deposits which finally raise it very considerably above the surface and separate it in construction from the lining to which it is attached. The shell herewith reproduced illustrates the result. Borers pierced it at the thick part of the hinge, and burrowing down, entered the interior at the point where the baroque is shown. In rare instances, pearls attached to the shell do escape the concentric deposition, for they have been found buried under even layers of nacre, when the mother-of-pearl was cut up in the process of manufacture. [Illustration: VENEZUELAN PEARL-SHELL, SHOWING BAROQUE] From the appearance of the striæ when they are divided lengthwise, pear-shaped pearls appear to have been spherical at one time. During a stage in the growth, the forming layer has curved away from the centre at one section of the sphere to a point. Succeeding layers, following the innovation, are deposited around the extension until it becomes sufficiently elongated to give the pearl the obovoid form. Many pearls are shaped like a capsule. The ends of most are rounded up to a full dome; some have somewhat flatter ends; many are long and cylindrical like an ordinary capsule; others are short and appear in shape like two high button pearls joined at their bases; while some resemble a cartridge, one end being almost flat and the other a somewhat pointed dome. It is noticeable that such pearls have a chalky line around the middle, and sometimes there is a lustrous band between two. These chalky lines are found, on peeling such a pearl, to extend through all the interior layers. Similarly, a high button joined at its entire circumference to the shell, if the junction is abrupt, has an intersecting chalky line, marking the juncture of the two, between the luster of the pearl and the shell lining. If the base of the pearl and the shell form a curve there is no chalky line of demarcation.