. The biology of the protozoa. Protozoa; Protozoa. 530 BIOIJICY OF THE I'h'OToZOA gametes fuse, a maeroganiete being fertilized by a single micro- gamete (g). The fertilized cell resulting from this fusion is the zygote in which the pronuclei fuse. The fertilization nucleus then divides and the two products divide again before the protoplasm divides into four parts, one about each of the nuclei. This process, or metagamogony, results in the formation of four sporoblasts within the sporocyst and each sporoblast has its own individual protective. Fig. 212.—Eimeria Schubergi. Sporozoites penetrat
. The biology of the protozoa. Protozoa; Protozoa. 530 BIOIJICY OF THE I'h'OToZOA gametes fuse, a maeroganiete being fertilized by a single micro- gamete (g). The fertilized cell resulting from this fusion is the zygote in which the pronuclei fuse. The fertilization nucleus then divides and the two products divide again before the protoplasm divides into four parts, one about each of the nuclei. This process, or metagamogony, results in the formation of four sporoblasts within the sporocyst and each sporoblast has its own individual protective. Fig. 212.—Eimeria Schubergi. Sporozoites penetrate epithelial cells and grow into adult intracellular parasites (a). When mature, the nucleus divides repeatedly (b), and each of its subdivisions becomes the nucleus of an agamete (c). These enter new epithelial cells and the cycle is repeated many times. After five or six days of incubation, the agametes develop into gamonts; some are large and stored with yolk material (d, e, ./'), others have nuclei which fragment into chromidia which become the nuclei of mierogametes (d, h. i, j\. A maerogamete is fertilized by one micro- gamete (g) and the zygote forms an oocyst (k). This forms four sporoblasts, each with two sporozoites (/). (After Schaudinn.) capsule (/). The nucleus of each sporoblast then divides and two independent cells are formed in each sporoblast. These indepen- dent cells arc the sporozoites. To recapitulate: Sporozoites come from sporoblasts; sporoblasts from zygotes; zygotes from fusion of gametes; gametes from gametoevtes, these from gamonts; gamonts from agametes; agametes from agamonts, and agamonts, originally, from 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 Calkins, Gary N. (Gary Nathan), b. 1869. Philadelphia, Lea & Febiger
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