Fig. 28 shows the pollen of the furze, in which are seen the longitudinal slits and the numerous dots on the surface; and Fig. 29 is the curiously shaped pollen of the tulip. The two large yellow globular figures at each side of the Plate represent the pollen of two common flowers; Fig. 36 being that of the crocus, and Fig. 37 a pollen-grain of the hollyhock. As may be seen from the illustration, the latter is of considerable size, and is covered with very numerous projections. These serve to raise the grain from a level surface, over which it rolls with a surprising ease of motion, so much so indeed that if a little of this substance be placed on a slide and a piece of thin glass laid over it, the glass slips off as soon as it is in the least inclined, and forces the observer to fix it with paper or cement before he can place it on the inclined stage of the microscope. The little projections have a very curious effect under a high power, and require careful focusing to observe them properly; for the diameter of the grain is so large that the focus must be altered to suit each individual projection. Their office is, probably, to aid in fertilisation. * * * * * The seeds of plants are even easier of examination than the pollen, and in most cases require nothing but a pocket lens and a needle for making out their general structure. The smaller seeds, however, must be placed under the microscope, many of them exhibiting very curious forms. The external coat of seeds is often of great interest, and needs to be dissected off before it can be rightly examined. The simplest plan in such a case is to boil the seed well, press it while still warm into a plate of wax, and then dissect with a pair of needles, forceps, and scissors under water. Many seeds may also be mounted in cells as dry objects, after being thoroughly dried themselves. A few examples of the seeds of common plants are given at the bottom of Plate III. Fig. 38 exhibits the fruit, popularly called the seed, of the common goosegrass, or Galium, which is remarkable for the array of hooklets with which it is covered. Immediately above the figure may be seen a drawing of one of the hooks much magnified, showing its sharp curve (Fig. 39). It is worthy of remark that the hook is not a simple curved hair, but a structure composed of a number of cells terminating in a hook. Fig. 40 shows the seed, or rather the fruit, of the common red valerian, and is introduced for the purpose of showing its plumed extremity, which acts as a parachute, and causes it to be carried about by the wind until it meets with a proper resting-place. It is also notable for the series of strong longitudinal ribs which support its external structure. On Fig. 41 is shown a portion of one of the parachute hairs much more magnified.