Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 CILIATA. 199 one or more rings of large cilia round the edge of a raised lid- like flap which is capable of being shut down. There is also an in- ferior row of cilia upon this flap running to the mouth. The free-swimming Infusoria often possess in addition to these delicate cilia and zones of cilia, thicker hairs and stiff bristles, and more or less bent hooks, which are em- ployed in locomotion and for attachment. Cer
Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 CILIATA. 199 one or more rings of large cilia round the edge of a raised lid- like flap which is capable of being shut down. There is also an in- ferior row of cilia upon this flap running to the mouth. The free-swimming Infusoria often possess in addition to these delicate cilia and zones of cilia, thicker hairs and stiff bristles, and more or less bent hooks, which are em- ployed in locomotion and for attachment. Certain fixed Infusoria as Stcntor (fig. 138) and Cothurnict secrete external coverings or shells, into which they retract themselves. Nourishment is taken in in a few cases by endosinosis through the whole surface of the body, , the parasitic Opalina. The Acineta feed themselves by sucking the body of their prey. They are without a mouth, and are incapable of taking in solid food. But they possess a number of long, narrow, contractile tentacles, which radiate from the surface of their bodies, and have the form of delicate tubes, presenting a structureless external wall and a semi-fluid granular axis. The Acineta applies one or more of these organs to the body of an extraneous organism, when the substance of interior of the FIG. pullet; vacuole FT, pulsatinp 2V, nucleus. granular axis of the the latter travels down the tentacle into the body of the Acineta (fig. 139). By far the greatest num- ber of Infusoria possess an oral aperture, usually near the anterior pole of the body, and a second aperture which acts as anus, and which can be seen in a definite part of the body as a slit during the exit of the excreta. rrii 11 i Fio. 139. — Acincla, ferrttnlequinum Ehvbjr., which is The ^body parenchyma, Mickinp thcbod/of & Illfus,,rl!111 () which is bounded by the (after Lachmann). T, sucking tentacle; V, vacuole ; , . N, nucleus. external membrane, is divided into
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