Dr. Holló Ferenc szerk.: Parasitologia Hungarica 3. (Budapest, 1970)
represent a normal location, at least partly, of the developmental stages, or just an effort of the host organism toward phagocytic destruction of the invading parasite. The intracellular location in relation to the nucleus is also typical of the eimerian parasites of Gallif ormes . The parasites may occur basally, adjacent to the nucleus or between the lumen and the nucleus. A species character is also the number of schizogonic generations succeeding each other until the start of the last - sexual - stage of endogenous development. 1. Endogenic d e velopment. Schizog ony. Cyst walls of most oocysts which entered the alimentary canal are burst under the influence of the host's body temperature, action of the digestive juices, primarily pancreatic juice or presumably also by the mechanical effect of the peristalsis. 10TZE and 1EEK (1969) state that part of the oocysts do not disintegrate and are eliminated with the stool. The sporocysts liberated by excystation release the sporozoites through the micropyle. Sometimes sporozoite excystation from the sporocyst takes place within the oocyst. According to DORAN and EARR (1962), the E. acervulina oocysts pass the crop without rupture, but start to release sporocysts in the gizzard, very likely owing to the latter' s mechanical effect. Sporozoites liberate in the duodenum and jejunum. The excystation of oocysts can be observed also in vitro. At appropriate temperature and under the influence of pancreatic juice and perhaps also other digestive juices,excystation takes a rapid course from a few minutes to a few hours. NYBERG, BAUER and KNAPP (1968) reported a stimulatory action of CO^ on in vitro excystation. On the basis of in vivo experiments ZUCKER (1964) pointed out the important role of dietary calcium content in the promotion of excystation by the pancreatic juice.
