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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 cyst. 



