3. _The Stellerides_, or _Asterias_, are the star-fish. The mouth in these creatures is in the middle of the lower surface, and it has a membranous lip, capable of great dilation, but furnished with angular projections for capturing its prey. The skin is soft, but leathery, and it is covered on the back with spongeous tubercles, or scales. The rays are hollow beneath, and furnished with tentacula, by the aid of which the star-fish manages to crawl backwards, forwards, or sideways, as the case may be, any of the rays serving as a leader. These animals are found on the sea-shore, forming large beds, which are washed over by the sea. _The Crinoidea_, or stone-lilies, of which such curious fossil specimens have been found, are nearly allied to the star-fish. II. _The Intestina_, or _Entozoa_. The intestinal worms were divided into two kinds by Cuvier, viz. the _Cavitaires_, including the worms of children, and other cylindrical worms; and the _Parenchymateux_, or flat worms; such as the fluke in sheep and the tape-worm in human beings. The Entozoa are now universally regarded as belonging to the Articulated or Annulose division of the animal kingdom. III. _Acalephæ_, or _Sea-Jellies_. These creatures are of a soft and jelly-like substance, with a thin skin, and an unarmed mouth. The Medusides are very numerous, and produce that beautiful phosphorescent light noticed by voyagers in the Australian seas. The most interesting of the Acalephes is the Portuguese man-of-war, or Physalia. IV. _Polyps_, or _Anthozoa_, according to Cuvier, were divided into three orders; namely: 1. _Fleshy Polyps_ (Sea anemones); 2. _Gelatinous Polyps_ (_Hydra_); and 3. _Polyps with Polyparies_, the latter including all the various compound zoophytes, with the Sponges. Of these the _Flustræ_, or _Sea Mats_, and numerous allied species, have since been recognised as belonging rather to the Mollusca, and the Sponges to a distinct and lower group of animals than the Radiata; the remainder have generally been divided into the following three orders:-- 1. _Helianthoida._ This order includes the actinia, or sea-anemone; and the madrepores, sea-mushrooms, and brainstones, which live in communities, and possess the power of secreting calcareous matters, which they emit to form these stony substances. 2. _Asteroida._ Some of the animals belonging to this division are called sea-pens, and others form some of the different kinds of coral, particularly that used for necklaces, &c.