Before treating of what are termed the _true_ Star-fishes, we require to dwell briefly upon an intermediate family named by Professor Forbes the _Ophiuridæ_, 'from the long serpent or worm-like arms, which are appended to their round, depressed, urchin like bodies.... They hold the same relation to the Crinoidea that the true Star-fishes hold to the Sea-Urchins. They are spinigrade animals, and have no true suckers by which to walk, their progression being effected (and with great facility) by means of five long flexible-jointed processes placed at regular distances around their body, and furnished with spines on the sides and membraneous tentacula. These processes are very different from the arms of the true Star-fishes, which are lobes of the animal's body, whereas the arms of the Ophiuridæ are super-added to the body, and there is no excavation in them for any longation of the digestive organs.'[16] [16] British Star-fishes. The British Ophiuridæ are now classed under two genera; of the Ophiuræ, or Sand-stars only two species (_O. texturata_ and _O. albida_) are found on our shores; and the Ophicomæ, or Brittle-stars, of which there are ten. An extraordinary feature, characteristic of all the above-mentioned animals, is the great tendency which they have to mutilate themselves, and throw their limbs about in fragments on the slightest provocation. If a specimen be handled, a certain number of fragments will assuredly be cast off. If the rays become entangled in sea-weed, or even if the water in which the animal resides happens to become impure, the same disastrous result follows, until nothing but the little circular disc remains. As a set off against this weakness, both the Ophiuræ and the Brittle-stars possess reproductive powers of a high order. Hence it not unfrequently happens that if each and all the rays of a specimen be rejected, the animal will live on, and eventually, perhaps, become a complete and perfect star-fish. The best means of preserving an Ophiura is to let the devoted animal remain for a time expanded in sea-water, then with a small pair of forceps lift it carefully up, and plump it into a bath of cold 'fresh' water, letting it lie there for about an hour. The animal speedily dies, as if poisoned, in the fresh liquid, in a state of rigid expansion. Some writers recommend that, at this stage, the specimen should be dipped for a moment into boiling water, and then dried in a current of air; but I have never been able to detect any great benefit arising from the adoption of the process. When examining any of the Brittle-stars, I have always found it an excellent plan to raise them up by aid of the forceps applied to the disc. By this means a specimen may be moved about without any fear of mutilation; whereas if the fingers be used as forceps, an unhappy result will assuredly follow.