Parasite
in botany, the parasites on plants are either animals or vegetables. Some of the latter are of high organization, as loranthus and orobanche among exogens, and epiphytal orchids among endogens. Many cryptogams in certain ferns, mosses, lichens, and fungals are parasites. The roots of the more highly organized parasites penetrate the substance of the herb at whose expense they feed. The lower parasites, by means of their cells, penetrate other cells to live in and on them.
In mineralogy, a plumose variety of boracite occurring in the interior of crystals of the same, and resulting from their partial alteration.
In zoölogy, an animal which lives in, on, or at the expense of the actual substance of another. Van Beneden divided parasites into three classes: (1) Parasites proper, living at the expense of the organic substance of the hosts, as the tapeworm; (2) commensals, who live with, or on, but not at the expense of their hosts, as sea anemones often live on shells of hermit crabs, and come in for a share of their prey; and (3) mutualists, a class not clearly defined, and now generally abandoned. Leuckhart PARCHMENT divided parasites into ecto- and endoparasites, according as they lived on or within, their hosts. Of the latter, by far the larger number belong to the type Vermes. Vertebrate parasites are rare, but exist among the Pisces. Myxine (the hagfish or borer) penetrates the abdominal cavity of gadoids, and feeds on their flesh.