Page:The New International Encyclopædia 1st ed. v. 04.djvu/934

CLASSIFICATION OF ANIMALS. 824 CLASSIFICATION OF ANIMALS. CLASSIFICATION OF AXIJIALS. List of Phyi^v, Classes, and Subclasses. Subdivision Protozoa ( Unicellular Animals) . Phylum I. Pkotozoa (Protozoans). Animals composed of a single cell; or, if of several cells, these are of one kind. Class 1. RiilzopODA. Protozoa with retrac- tile pseudopodia (AiiKrba, etc.) Class 2. Mycetozoa. Terrestrial protozoa, plasniodial, and forming large and complex cysts (Slimes). Class 3. ilAsriGOPUOKA. Protozoa with- out cilia, but with one or more flagella. Class 4. Si'oKozoA. Protozoa, without ap- pendages; internal parasites. Class 5. Ikfusobia. Protozoa with cilia, or sucking tentacles. SuiiDivisioN Metazo. {Multicellular Animals). Phylum II. PoRiFEKA (Sponges). Fixed aquatic iletazoa, whose body-wall is perforated by incurrent pores. Class PoRlFERA. Equivalent to the Phylum. Subclass 1. Calcarca. Sponges with skele- ton of calcareous spicules. Subclass 2. Non-Calcarca. Skeleton, when present, composed of siliceous spicules or of spongiu fibres. Phylum III. CcELENTEKATii. (Polyps, etc.). Animals of radial structure, whose digestive cavity is lined by the body-wall, and which have nettling organs. Class 1. Hydrozoa. Cielenteratcs, whose body is com])osed of more than two rays, and contains a single cavity ( Hydroids, Siphonophores, etc.). Class 2. ScvpiiozoA. Ccelenterates with many radii, and with radial partitions in the cavity of the body (Jellylishes). Class 3. AcTiNOZOA. Attached individuals or colonies. Subclass 1. Zoantharia. Tentacles numer- ous, and usually in multiples of five (Sea-Anemones, Madrepores, and Corals). Subclass 2. Alci/onaria. Tentacles, eight only (Red Corals, Sea-Fans. etc. ) . Class 4. C'ti:xoi"iioka. Co-lenteratcs with only two radii, and rows of cilia- jilates. Phylum IV. l'LATYiiELMiXTin:s (Flatworms). Bilaterally symmetrical, soft-bodiod animals, withciui true segmentation of the body; tlattened in a dorso-veiitral direction, and having the body- cavity filled with a loose meslnvork of cells. Class 1. TuimELi.ARiA. Free-living flat- worms, whose body is covered by cilia ; alimentary tract with only one oi)ening to the exterior (Planarians). Class 2. TitEMATOOA. Parasitic, unseg- mcnted. without cilia in the adult, and with a well-developed digestive apiiaratus (Flukes). Class 3. Cestoda. Elongated, usually un- segmented hermaphrodite endo- parasites, without mouth or ali- mentary canal (Tapeworms, etc.). Class 4. XE.MERTINEA. Body more or less- llattcned; food-canal with mouth and arms; aquatic, carnivorous. Subclass 1. I'alwonemcrlineu. Subclass 2. iSchizononertea. Subclass 3. Hoplonemerica. Phylum v. Nem.vtiielmixtiies (Round- worms). Bilateral, unsegmeuted, round-bodied; usually with alimentary tract, mouth, and arms. Class 1. Ne.matou.. With intestinal canal ; without proboscis; free-living in fresh or salt water, .or parasitic (Threadworms) . Class 2. AcAXTHocEPiiALA. Mouth and in- testines wanting; parasitic. Class 3. C'li.ETOGNATHA. Pelagic 'arrow- worms;' spiny, and with a well- developed nervous system. Phylum VI. Troohelmintiies (Wheel-Ani- malcules.) Characterized by having the larva in the form of a irochosphere. Class 1. KoTiFERA. Microscopic wheel- animalcules, with a ciliated band around the mouth, and a special organ for attachment. Class 2. Dixopuilea. Minute, wonn-like,. having five to eight segments, usually ciliated; and nephridia in pairs; marine. Class 3. Gastrotricha. Minute, spindle- shaped, flattened and ciliated on the ventral surface ; fresh waters. Phylum VII. JloLLUSCoiDA (Sea-^Mats and Brachiopods) . Snutll aquatic animals, having a. true body-cavity (except in Endoprocta) and suspended alimentary canal ; dorsal region ab- breviated and surmounted by lophophore. Class I. Poi-YZOA. Molluscoida that form colonics connected by one organic substance; the ciliated band of the lophophore is drawn out into tentacles ( Bryozoans ) . Subclass 1. Ediiprocta. Anus outside ten- tacular corona. Subclass 2. Endoprocta. Anus internal ; form colonies by budding. Class 2. PiiORONiDA. Worm like poly/.oans, living in associations of individu- als born from oa. not by buds. Class 3. Brac'IIIopoda. Polyzoa with the bod}- inclosed in a shell of two valves; body usually attached by a stalk (Lamp-Shells). Phylum VIII. Echi.xoder.mata .(Echino- derms). Animals of prevailingly radical struc- ture, with intestinal wall distinct from body-wall, and with calcareous plates in the skin. Class 1. AsTERoiiiEA. Star-shai)ed echino- derms, with a furrow (ambula- crum) along the under side of (he arms (Starfish). Class 2. OpiiirRoiDEA. Star-shaped echino- dcrnis, with the arms sharply marked ofT from the body, and not grooved (Brittle Stars). Class 3. Ec'iiixoinEA. Echinoderms with the body globular or disk-shaped, and armless ( Sea-l'rchins) . Class 4. lIo[.(rriuRoii)EA. Echinoderms elongated, worm-like, usually soft, and with tentacles about the mouth (Trepangs).