Step 5: Near the bottom corner of the rectangular shape, lightly sketch a small circle for the eye. When you get the position and size of the circle right, darken the shape. Inside, draw a tiny circle to represent glare. Shade the eye using a medium value but don't overlap the tiny glare circle. Use a slightly darker value near the top and middle of the manta ray's eye to emphasize the pupil. Draw a few curved lines around the eye for extra detail on the skin. Add some lines close to the eye and some a little farther for more structure. The second eye is on the other side of the head, so it won't be visible from this angle.
Step 6: Add the manta ray's open mouth to the left of the eye by first drawing a curved line. Sketch lightly at first. The top part of this line should be almost parallel to the side of the initial rectangular guide. The ends of this line should dip down toward the side of the guide. When you get the shape right, darken the line. Draw another line under the first one for the bottom part of the open mouth. The bottom line should curve too. Make the top line darker and thicker.
Step 7: Continue drawing the line for the mouth downward to form an arc and create the manta ray's cephalic lobe. Sketch lightly at first. The right tip of this line should end at the corner of the initial rectangular shape. When you get the shape right, darken the line. The overall shape should be similar to the letter U.
Step 8: Draw the manta ray's other cephalic lobe fin the same way. Continue the line for the mouth downward to create an arc. Sketch lightly at first. This lobe should be smaller than the first one because of the angle. Like before, the overall shape should be similar to the letter U, but the bottom part should curve to the right.
Step 9: Use the initial rectangular shape as a guide to draw the head. Continue to draw the line from the cephalic lobe upward as you follow the basic path of the initial guide. Darken the line below the eye for the side of the head and the line below the mouth for the bottom of the head. The line at the bottom should follow the same curvature as the manta ray's mouth.