. A manual of elementary zoology . Zoology. 154 MANUAL OF ELEMENTARY ZOOLOGY The gamonts begin to arise when the period of incuba- tion is past. In the parasites of tertian and quartan fevers they are rounded, in that of pernicious malaria crescent- shaped. They are larger than the schizonts and have more of the dark pigment. It is said that they have no ring-stage in their develop- ment. They remain in the corpuscle where they arose from a trophozoite, and undergo no change unless they be sucked in by a mosquito; but in that case, whereas all other forms of the parasite die and are digested b
. A manual of elementary zoology . Zoology. 154 MANUAL OF ELEMENTARY ZOOLOGY The gamonts begin to arise when the period of incuba- tion is past. In the parasites of tertian and quartan fevers they are rounded, in that of pernicious malaria crescent- shaped. They are larger than the schizonts and have more of the dark pigment. It is said that they have no ring-stage in their develop- ment. They remain in the corpuscle where they arose from a trophozoite, and undergo no change unless they be sucked in by a mosquito; but in that case, whereas all other forms of the parasite die and are digested by the mosquito, the gamonts, becoming free by the breaking up of their corpuscles, proceed to develop gametes. They are of two kinds, male and female, the former with a larger nucleus and more lightly staining cytoplasm than the latter. In the male gamont the nucleus breaks rapidly into some half-dozen frag- ments, leaving a residual mass in the central cyto- plasm. The daughter nuclei come to the surface, and grow out, with a suddenness which is almost explosive, into fine threads of nucleo- plasm, projecting from the body in scarcely perceptible sheaths of cytoplasm. These are the microgametes. They lash violently, dragging about till they break free. The The female gamont, by the. Fig. 95.—A mosquito (Anopheles). —From Lankester's Zoology. residue of the gamont body, remains of the gamont perish. division of the nucleus to cast off a " reduction nucleus," becomes a single macrogamete. It is now ripe for fertilisa- tion by a microgamete which penetrates the body, and the nuclei (male and female pronuclei) fuse. The zygote changes from a rounded to a worm-like creature, which glides about by contractions of its body, pierces the epithelium of the insect's stomach with one end, which is pointed for the purpose, and comes to rest in the sub- epithelial tissue, where it rounds itself off and forms a Please note that these images are extracted from scanned pag
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