We select the latter species for illustration. It is abundantly common all round the British coasts, as well as on those of western and southern
Europe. It attains a diameter of two feet; is brown above with paler spots, and white beneath. The whole upper surface is rough with minute points, and is studded with an irregular number of large hooked spines. The structure of these is peculiar; each consists of an oval, rather thick disk of white bone, the centre of which rises into a sharp conical point curved backwards, the whole possessing a slight resemblance to one of the prickles on the stem of a rose-bush. A group of small ones of similar form surround each eye, and a row runs down the middle of the back in close series. The others are much larger, and irregularly scattered both over the body and the tail.
The Thornback is much eaten by the poorer
