The worms are arranged by V. Carus into the five following classes: (1.) Annulakt.
corresponding to the annelids of Owen, and described in the article ANNELIDA. (2.) Gephyrea, including the sipunculus and its allies. (The term is derived from the Greek gephyra, a bridge, because the animals included in it form a connecting link or bridge between the echinoderms and the true articulate animals.) In the article Sipunculus (q.v.), in which, according to the old view, that animal is regarded as an echinoderm, there is a figure of a British species, the sipunculus Bernhardus. (3.) Chcetognatha (sig nifying shaggy-jawed, from the Greek chaitOeis, shaggy, and gnathon, a jaw), including the single genus sagitta, which was formerly erroneously placed among the nueleo branchiated mollusks. As the sagitta is not elsewhere described in this work, we may notice that it is a little fish-like animal with a distinct head, the mouth armed with sev eral pairs of lateral hook-like jaws, with an elongated body furnished with one or two pairs of fin-like organs, and with a broad and usually bibbed caudal fin. The sagitta (so called from its arrow-like appearance) is of small size, swims with great rapidity, and is common in the Mediterranean and in the North sea. (4.)Nematelmta (from the Greek nema, a thread, and helmins, a worm), which are described in a special article. (5.)
Platyelmia (from the Greek platys, flat, and helmins, a worm), or jlat-worms, which are divisible into the three orders: (1) Turbellaria, including the planarian, etc. ; (2) .7).ema toda, including the flukes; and (3) Cestoiclea, including the tapeworms. These orders are described in special articles.
For further information on the subject of this article the reader is referred to the various works and memoirs of Milne-Edwards, Grube, De Quatrefages (especially his Rambles of a Naturalist), Schmarda, Blanchard, Leuckart, Williams of Swansea (in the reports of the British association), etc. The British worms were not till quite recently described by any competent naturalist, although the labors of Williams of Swansea and Johnston of Berwick (both too early lost to science), are excellent as far as they go. Dr. Johnston's Catalogue of the British Non-parasitical Worms in the Collection of the British. Museum (Land. 1865, p. 366), with 20 plates, must be consulted by all who take an inter est in this subject, although much of it is now out of date. The most complete work is the Monograph of British Annelides, published under the auspices of the Ray society by Dr. Macintosh of Murthly, one of the most distinguished of the younger genera tion of Scottish naturalists.
is the popular name for santonica, from which santonine (q.v.) is ex tracted.