Thornback (Raia clavata), a species of ray or skate, common on most parts of the British coast. It attains a large size; the snout or fronto-nasal process is short, and the form is nearly rhombic. The upper surface is brown, with lighter spots, the under surface white. The upper surface is rough with minute sharp scales, and has numerous nail- like crooked spines, each with an oval bony base. A few strong spines may also occur on the ventral surface, especially in the female. In the male the teeth are pointed, in the female flat. The thornback is used as food, particularly in autumn and winter, but is most abundantly captured in spring and summer, when it approaches the shore to deposit its eggs.