Acanthi as (akan′thias)

[NL., 29 have neither mouth nor alimentary canal, but have recurved hooks on a retractile proboscis at the anterior end of the body, by which they attach themselves to the ti ues of animals. These entozoans belong to the cla Nematelmintha. The embryos are gregarina-like, and become encysted as in Ces tod a, in which state they are swallowed by various animals, in the bodies of which they are developed. A species occurs in the liver of the cat, and another in the alimentary canal of the hog. There are about 100 species, all referable to the family Echinorhynchida. The Acanthocephala undoubtedly present certain resemblances to the Nema to idea, and more particularly to the Gordiacea, but the fundamental differences in the structure of the muscular and nervous systems, and in that of the reproductive organs, are so great that it is impo ible to regard them as Nematoids which have undergone a re trogre ive metamorphosis. Huxley, Anat. Invert., p. 558.