The image is a detailed, monochrome illustration of a cross-section of an echinus spine. It appears to be a scientific or anatomical drawing, likely from a vintage publication. The spine section is circular, densely packed with a complex, radial pattern of tiny dots and lines. The pattern resembles a tightly wound spiral or concentric circles, with the density of the dots increasing towards the center. The overall texture is granular and intricate, suggesting a microscopic view of the spine's internal structure. The image is set against a plain, off-white background. Below the image, there is text identifying it as 'FIG. 15. ECHINUS SPINE SECTION. x 60.' and '[to face page 68.'