Step 10: Draw the mandrill's nose inside the head using a series of curved lines. First draw a curved, broken line from the left eye to the bottom of the initial circle for the bridge of the nose. Add a few more broken lines on the right side to make the bridge of the nose thicker. Use the initial lines to guide you in drawing the curve of the bridge of the nose. At the bottom of the monkey's nose, draw a couple of short, curved lines that point down for the nostrils. Add a couple of lines around the nostrils to complete the shape of the nose.
Step 11: Under the nose, draw a horizontal line that curves up on the right for the mouth. Break up the line a bit to represent the hair around the mouth. Add short strokes below the mandrill's mouth for more hair. Follow the basic path of the guide to draw the hair on the chin. The short strokes should dip below the guide to form a sort of goatee around the mouth.
Step 12: Draw a series of curved lines in the space between the eye and the nose for the ridges on the face. Start below the eyes and draw short, curved lines that meet the nose at the bottom. Add a couple of sloping lines that connect the bridge of the nose to the curved lines. The ridges on the right side should be wider because of how the mandrill's head is turned. Add a few sloping lines along the edge of the bridge of the nose for the grooves. Add the short, curved lines along the right side to complete the shape of the ridges on the face.
Step 13: On the top, right side of the head, draw a line similar to an upside-down letter V for the ear. Below the mandrill's ear, draw a series of short strokes for the fur in front of the ear.
Step 14: Draw a curved, horizontal line over the eyes for the heavy brow. Draw a few short, curved vertical lines above to emphasize the thickness of the mandrill's brow. Above the thick brow, draw a series of short strokes for hair.
Add a few short strokes above the brow for a patch of hair on the forehead. This patch of hair should be similar to a small arc that's made up of short strokes.
Use the initial circle as a guide to draw the rest of the monkey's head. Follow the basic path of the circle and draw short strokes along the edge for the hair. At the top, draw the short strokes higher than the initial circle to make the head bigger. Draw more short strokes along the guides at the bottom to finish the shape of the head.