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.
3. Hydroida. This order includes the fresh-water polypi, which, it is well known, by the experiments that have been tried, may be cut in pieces and even turned inside out without destroying life. It must be observed that the contents of this group in Cuvier’s system consisted of all those forms of animals which he could not, in accordance with the knowledge possessed in his day, conveniently place anywhere else. Within the last few years, however, great progress has been made in the arrangement of the animals placed in this group by Cuvier. One of the most important changes has been the establishment of a fifth group of animals for the Infusoria and Sponges, together with certain other creatures of very low organisation. To these the name of Protozoa has been given. The Entozoa have been removed amongst the articulate animals, and there is a growing conviction that the Echinodermata will have to be transferred to the same section. There remain, consequently, the Acalephæ and Polyps of Cuvier, which form a group characterised by their soft and generally gelatinous texture; by the existence of peculiar cells, called thread cells, in the skin; and by their possession of an alimentary cavity with only a single orifice. To these the name of Cœlenterata has been given. They are divided into two classes: I. The Anthozoa, or Polyps, including the orders Helianthoida and Asteroida; and II. The Hydrozoa, composed of the Hydroid Polyps and Acalephæ, the connection between which, as indicated in the text (p. 609), is very intimate.
V. The Infusoria, or Animalcula, are so small as to be invisible to the naked eye, and they are all inhabitants of liquids. Cuvier arranged them in two orders, one of which he called Les Rotifères, and the other Les Infusories homogènes, but the first of these divisions is now included among the Articulata. The remainder of the Infusoria of Cuvier, with the exception of some which are now known to be of vegetable nature, are arranged, with the Sponges and some other animals, in a separate division, called Protozoa, the classification of which is still in a somewhat uncertain state. The three principal classes are those of the Infusoria, the Sponges, and the Rhizopoda; but there are other forms which will not admit of being brought under any of these denominations. Nearly all the Protozoa are microscopic, except when, as in the case of the Sponges, they form an aggregation of individuals. They are very numerous, and, although exceedingly simple in their structure, their history often possesses much interest.
EXPLANATION
OF
TERMS USED IN NATURAL HISTORY.
| Abdomen. | The part of the body containing the organs of digestion. |
| Abdominal. | Pertaining to the abdomen. |
| Amphibious. | Capable of living both on the land and in the water. |
| Animalcules. | Small animals, visible only with the assistance of the microscope. |
| Annulated. | Marked with rings. |
| Antennæ. | The horns or feelers of insects. |
| Apex. | The top or summit of anything. |
| Apical. | Situated at, or belonging to, the apex. |
| Apodal. | Footless. |
| Apterous. | Wingless. |
| Aquatic. | Living or growing in the water. |
| Bicuspid. | Having two points. |
| Bifid. | Divided into two parts. |
| Bifurcated. | Divided into two prongs. |
| Bisulcous. | Cloven-hoofed. |
| Bivalve. | With two shells. |
| Branchiæ. | Gills, or organs for aquatic respiration. |
| Buccal. | Pertaining to the mouth. |
| Byssus. | A tuft of silky filaments produced by some Mollusca. |
| Callosity. | A hard lump, an excrescence. |
| Campanulate. | Bell-shaped. |
| Canine. | Of the dog kind. |
| Carinated. | Keeled. |
| Carnivorous. | Feeding on flesh. |
| Caudal. | Pertaining to the tail. |
| Cere. | A skin over the base of the bill of birds. |
| Cervical. | Belonging to the neck. |
| Cetaceous. | Of the whale kind. |
| Cilia. | Microscopic filaments, which, by their constant vibration, either cause currents in the water, or move the animals possessing them. |
| Cinereous. | Of the colour of ashes. |
| Clavate. | Clubbed. |
| Cordiform. | Heart-shaped. |
| Coriaceous. | Leathery. |
| Corneous. | Horny. |
| Crustaceous. | Covered with a shell or crust; as lobsters, crabs, &c. |
| Dentate. | Toothed like a saw. |
| Dorsal. | Belonging to the back. |
| Elytra. | The wing-cases of insects of the beetle tribe. |
| Emarginate. | Notched. |
| Entomology. | A description of insects. |
| Exsanguineous. | Without red blood, as worms. |
| Feline. | Belonging to the cat kind. |
| Ferruginous. | Of an iron or rust colour. |
| Filiform. | Thread-like. |
| Foliaceous. | Leaf-like. |
| Frugivorous. | Feeding on fruits. |
| Furcated. | Forked. |
| Fusiform. | Spindle-shaped. |
| Gallinaceous. | Belonging to the hen kind. |
| Gelatinous. | Like jelly. |
| Gemmiparous. | Capable of propagating by buds. |
| Geniculate. | Bent like a knee. |
| Gestation. | The time of going with young. |
| Granivorous. | Feeding on grain. |
| Gregarious. | Associating together. |
| Hastate. | Formed like an arrow-head. |
| Haustellate. | Insects with a mouth adapted for suction. |
| Herbivorous. | Feeding on grass. |
| Hexapod. | Having six legs. |
| Hyaline. | Glassy. |
| Ichthyology. | A description of fishes. |
| Imbricated. | Tiled, or lying over each other. |
| Incubation. | The act of hatching eggs. |
| Insectivorous. | Feeding on insects. |
| Intestinal. | Pertaining to the digestive organs. |
| Laminated. | Covered with or divided into plates or scales. |
| Larva. | The young of insects. |
| Lateral. | Belonging to the side, placed sideways. |
| Loricated. | Covered with hard scales or plates like armour. |
| Lunate. | Crescent-shaped. |
| Mandibles. | Upper and lower, the two divisions of a bird’s beak, or the projecting jaws of an insect. |
| Migratory. | Coming and going at certain seasons. |
| Multivalve. | With many shells or openings. |
| Nacreous. | Resembling mother-of-pearl. |
| Nictitating. | Winking; applied to a membrane with which birds cover their eyes at pleasure. |
| Olfactory. | Relating to smell. |
| Operculum. | A shield or cover. |
| Ornithology. | A description of birds. |
| Oviparous. | That lays eggs. |
| Palmated. | Webbed. |
| Parasitic. | Attached to and dependent on some other living body. |
| Parturition. | The act of bringing forth young. |
| Passerine. | Belonging to the sparrow tribe. |
| Pectinate. | Resembling a comb. |
| Pectoral. | Belonging to the breast. |
| Pendulous. | Hanging down. |
| Piscivorous. | Feeding on fishes. |
| Plicate. | Folded. |
| Predaceous. | Formed to pursue prey. |
| Prehensile. | Capable of grasping. |
| Quadrifid. | Divided into four parts. |
| Quadruped. | Four-footed. |
| Ramose. | Branching. |
| Reptiles. | Animals of the serpent tribe, with legs. |
| Rudimentary. | Small; imperfectly developed. |
| Ruminating. | Chewing the cud. |
| Scabrous. | Rough. |
| Scapulars. | Shoulders. |
| Semilunar. | In the form of a half-moon. |
| Serrated. | Notched like a saw. |
| Sessile. | Attached without the intervention of a stalk. |
| Setaceous. | Having bristles or strong hairs. |
| Spiral. | Winding like a screw. |
| Squamose. | Scaly. |
| Striated. | Streaked or striped. |
| Subulated. | Formed like an awl. |
| Sulcated. | Furrowed. |
| Suture. | The line of junction of two hind parts. |
| Tentacula. | The feelers of snails and other mollusca. |
| Testaceous. | Covered with a shell, as oysters. |
| Trifurcated. | Three-forked. |
| Truncated. | Appearing as if cut off. |
| Tubicolar. | Inhabiting a tube. |
| Univalve. | With one shell or opening. |
| Ventral. | Belonging to the belly. |
| Vertebrated. | Having a jointed spine-bone. |
| Viscera. | The organs contained in the cavities of the body. |
| Viviparous. | Bringing forth the young alive. |
| Webbed. | Connected by a membrane, as the toes of aquatic birds. |
| Xylophagous. | Wood-eating. |
| Zoologists. | Writers on animated nature. |
| Zoology. | The history of animated nature. |
TABLE OF CONTENTS.