Zoology of the invertebrata : a text-book for students / by Arthur E. Shipley.
- Arthur Shipley
- Date:
- 1893
Licence: Public Domain Mark
Credit: Zoology of the invertebrata : a text-book for students / by Arthur E. Shipley. Source: Wellcome Collection.
107/474 page 95
![95 ]». Dendrocoelida. — Forms with flattened body and branched intestine. Testes and ovaries follicular. Otocysts very rare. Tribe 1. Tricladida.—Body elongated. Intestine in three main branches, which diverge from a cylindrical retractile proboscis. Testes and vitellarium follicular. Germa¬ nium compact. Genital aperture single. Planaria and Dendrocoelum live in fresh water. Gunda, which shows traces of metameric structure, and Bdclloura, which is an ectoparasite of limulus, are marine. The leech-like land planarians are chiefly tropical. Rhyncliodemus terrestris and Geodesmus bilineatus are European. The former is found in England amongst damp bark, etc., in gardens and woods. Tribe 2. Polycladida.—Body thin and broad. Numerous branched intestinal caeca open into the stomach. Testes and ovaries follicular. Genital apertures separate, the male anterior to the female. A ventral sucker some¬ times present. Marine, Thysanozoon, Yuimia O 7 ^ • Class II. CESTODA. Characteristics. — Bndoparasitic Platyhelminthes, devoid of mouth and alimentary canal. Organs of adhesion, in the shape of chitinoid hooks or suckers, enable the parasite to attach itself to its host. The nervous system is composed of a cerebral ganglion and two lateral nerve cords. The coelom is represented by irregular splits in the mesodermic paren¬ chyma. The decretory system is of the Platyhelminthine type, opening to the exterior by one or more pores, which are sometimes furnished with a pulsating vesicle. The Cestoda are hermaphrodite, the generative organs being usually repeated many times. < hie ol the commonest Tapeworms found in man is Taenia saginata (mcdiocanellata) (Fig. G6), and it will be a convenient form to describe. The worm in question may attain a length of five or six yards, and may be composed of many hundred segments, often](https://iiif.wellcomecollection.org/image/b29316194_0107.jp2/full/800%2C/0/default.jpg)
