. Elementary text-book of zoology. CORTICATA. PHYLUM CORTICATA. The CoRTiCATA contain the important class Ciliata, of which Paramoecium and Vorticella are typical. They are all active organisms, those like Faramacium moving rapidly in pursuit of pre)', whilst others like Vorticella are themselves fixed and use their cilia to bring food-particles to them. They are divided into orders according to the arrangement of the cilia. The second class is that of the Mastigophora. They are also small active organisms, often of very minute size. They have only one, or sometimes two, long whip-like process
. Elementary text-book of zoology. CORTICATA. PHYLUM CORTICATA. The CoRTiCATA contain the important class Ciliata, of which Paramoecium and Vorticella are typical. They are all active organisms, those like Faramacium moving rapidly in pursuit of pre)', whilst others like Vorticella are themselves fixed and use their cilia to bring food-particles to them. They are divided into orders according to the arrangement of the cilia. The second class is that of the Mastigophora. They are also small active organisms, often of very minute size. They have only one, or sometimes two, long whip-like processes which are csWeA flagella. The flagellum may be situated at the posterior end and serve to drive the body forwards, in which case it is called a pulsellum, or it may be at the anterior end and may draw the body after it, when it is known as a tradellum. The tractellum may also by spiral movements assist in bringing food to the mouth. In one large section of these Mastigophora, often placed in a class by themselves, the Choc^/io-Flagellata, the ingestive action of the tractellum is supplemented by a "collar" of protoplasm which surrounds the mouth and the base of the tractellum. Colonial forms are common in this class. The AciNETARiA are a spe- cialised class of much the same general habit of life as the pre- ceding classes, but there are no cilia nor flagella. Their place is taken by a number of fine pro- Cesses terminating in minute suckers or adhesive discs with which other Protozoa are caught and their juices extracted. Most are fixed and stalked, but some are free and even parasitic. The young are often actively ciliated, and the whole class is probably derived from ancestral Ciliata. Fig. 36.—ACINETA Tu- BEROSA Expanded and Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Maste
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