Step 10: Inside the eye, off to the side, draw a tiny circle to represent glare. In the middle, add a dot for the pupil. Above the eye, draw a curved line for the dimetrodon's bony brow. Add more short, curved lines around the eye for wrinkles on the skin.

Step 11: Use the bottom part of the big arc on the left as a guide to draw the first part of the mouth. Darken the edge of the arc but make the line wavier and longer to create the mouth. Inside the initial arc, on the left side, draw a small slit with a line underneath for the dimetrodon's nostril.

Step 12: Use the small arc at the bottom as a guide to draw the lower jaw. Follow the path of the arc but make the front tip flatter. Extend the line on the right to meet the top part of the dimetrodon's mouth.

Step 13: Draw a series of small, triangular shapes that line the mouth for the teeth. Dimetrodons had teeth of varying sizes, so don't make all the shapes the same size. On the right side, draw a few curved lines for the tissue connecting the jaws.

Step 14: Use the remaining lines and shapes as guides to draw the rest of the head. Darken the outer edges of the initial shapes to create the shape of the head. Add a few lines inside the head for extra detail and darken the line for the neck at the bottom too.