BOTHB,IOCEPH'ALIIS (Gr. buthrion, a little pit, and cephale, a head/, a genus of intestinal worms, belonging to the order of cesloid -worms (q.v.), and included, until recently, in the genus &mill, (tape-worm, q.v). The head in this genus is not furnished with four suck ing disks, as in the true tape-worms, but with two lateral longitudinal hollows, which seem to serve only for adhesion by means of a partial vacuum, and to have nothing to do with nutrition. Nourishment is indeed supposed to be obtained entirely by the imbib ing of fluids through the entire length of the worm; and whilst this process of imbibing takes place, there is also an exudation—as eraintose accompanies endomone (q.v.) in the roots of plants—of peculiar oleaginous drops, which may probably be in part the cause of the injurious effects produced by these worms upon the health of the animals infested by them. The species of B. are very abundant in predaceous fishes, and occur more sparingly in fish-eating birds; the immature and sexlessyoung being found in fishes and inferior aquatic animals, either in peculiar cysts, or in the intestinal canal. Stickle backs are often seen distended to an unusual size by a species of B. which lies free in the cavity of the abdomen; but iu the stickleback its joints and sexual organs always remain undeveloped; it is only when the stickleback has been digested in a bird's stom ach, that the B., released, and finding itself at last in suitable circumstances, acquires its
mature form, becoming an inhabitant of the bird's intestines. Only one species of B. occurs in man. B. latex, which is at once distinguished from the common tape-worm by the different form of its segments, but has been often confounded with another species of tape-worm, tinder the name of broad tape-worm. The segments are much broader than they are long, and each contains organs of reproduction. The worm is strictly androgynous. It is scarcely known in Britain. but is of frequent occurrence iu some parts of Europe, and sometimes attains a length of 15 ft. or upwards; and a coil of these worms is not unfrequently expelled at once from the patient. The B. is, however, much more easily expelled than the true tapeworms. The same means are employed. The geog,Taphieal distribution of this worm, which is most frequent in low marshy countries. has led to the conjecture, that its youngest brood may inhabit some of the smallest aquatic animals, and that it may find its way into human beings by their eating salads, fruit which grows near the ground, or the like.