Elementary text-book of zoology . elementarytextbo0101clau Year: 1884 208 PROTOZOA. the central mass. The structure of the body may be complicated by the pre- sence of a partition wall which parts off the anterior end from the main mass of the body. The anterior portion of the body gets in this way the appearance of a head, upon which there may be formed here and there prominences in the form of hooks and processes for the purpose of attachment. Nourishment is effected by endosmosis, through the external walls. Motion is confined to slow gliding forward of the feebly contractile bod}'. In the
Elementary text-book of zoology . elementarytextbo0101clau Year: 1884 208 PROTOZOA. the central mass. The structure of the body may be complicated by the pre- sence of a partition wall which parts off the anterior end from the main mass of the body. The anterior portion of the body gets in this way the appearance of a head, upon which there may be formed here and there prominences in the form of hooks and processes for the purpose of attachment. Nourishment is effected by endosmosis, through the external walls. Motion is confined to slow gliding forward of the feebly contractile bod}'. In their full-grown state the Gregarina are frequently seen fastened to one another two or more together. This connected state precedes reproduction (fig. 149). The two individuals lying with their long axes in the same straight line contract and surround themselves with a common cyst, and after undergoing a process resembling segmentation, divide into a number of small spore- like balls, which become spindle- shaped bodies (PseudonavicellEe). The cyst secreted round the congre- gating individuals, or, as is often the case, round a single individual, be- comes a Pseudonavicella cyst, and by its bursting the spindle-shaped bodies reach the exterior. The contents of each Pseudonavicella sometimes gives rise to a small amoeboid body, as may be inferred from Lieberkiihn's obser- vations on the Psorosperms of the pike. In other cases (Mvnocyxtis, 6ront>xj>»ra, etc.) sickle-shaped bodies arise in the spores, which, without passing through an amoeboid stage. give rise to young Gregarines. Mono- ci/xtix iiffilift from the testis of the earth-worm. Gn-garina L. Duf. (Clepsidrina Hammersch.) Body with flat partition wall and wart-like head at anterior end. In the young stage the anterior end of Gr. blat- tariim v. Sieb. is fixed in the cells of the intestinal epithelium of Blatta. Gr. polymorpha Hammersch. in the meal- worm. [The Gregarines are found mainly in Invertebrata. They may be
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