. A manual of zoology. Zoology. 1S2 rROTOZOA contractile vacuole are usually lacking (figs. 138, 130, 140. 141)• There are usually one or two llagella at the anterior end; when more occur (eight or move) they are distrihuled over the body. They difler in form and function so that chief, accessory and trailing llagella are distinguished. In the parasitic species there is usually a duality of the nucleus, recalling that of the Infusoria, there being, besides the principal nucleus, a second, the hlcpharophisl, at the base of the llagellum (lig. I v"^, (). The surface of the body is frequentl
. A manual of zoology. Zoology. 1S2 rROTOZOA contractile vacuole are usually lacking (figs. 138, 130, 140. 141)• There are usually one or two llagella at the anterior end; when more occur (eight or move) they are distrihuled over the body. They difler in form and function so that chief, accessory and trailing llagella are distinguished. In the parasitic species there is usually a duality of the nucleus, recalling that of the Infusoria, there being, besides the principal nucleus, a second, the hlcpharophisl, at the base of the llagellum (lig. I v"^, (). The surface of the body is frequently naked, and then is often capaljlc of anuclioid motions. Again it may be covered with a more or less evident cuticle. Closed gelatinous en- velopes or open, goblet-shaped cups [loricir, tig. 135) are common. There may also be slender stalks, to which he animals are attached in small groups (fig. 130). There are great differences in the feeding and in the organs connected therewith. ]Many feed like animals, taking solid food with pseudopoiha like the Rhi/.opotla or with a mouth like the Infusoria. In the Choanollagellata (lig. 136) tlrere is a collar, a funnel-like process of the body protoplasm around the flagellum, to which foreign particles thrown by the fiagellum adhere and are conveyed to the interior. Besides these animal forms are plant-like species which contain cHorophyl (V'olvocina-, liuglenida^) or l)rown chromatophores (Chromomonadinea-), aiding in assimilation and ena- bling the organism to produce paramylum or even starch. It is note- worthy that vegetable ami animal methods of nourishment appear in forms closely related anatomically. Indeed, there are species which possess a cytostome without taking solid nourishment, assimilating 1iy means of chlorophyl or living on Ihiid food (fig. 137). All this shows that the I'iagellata ha\e relations with Rhizopoda, Infusoria, and the lower plants (bacteria and alga-).. Fig. 13S.—Trypaiiosoina Irwisi (after I^a\'eran el
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
