SPOROZOA, GREGARINIDA 



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Suborder 1 Eugregarinina Doflein 



This suborder includes the majority of the so-called gregarines 

 which are common parasites of arthropods. When the spore gains en- 

 trance into a suitable host, it germinates and the sporozoites emerge 

 and enter the epithelial cells of the digestive tract. There they grow 

 at the expense of the host cells which they leave soon and to which 

 they become attached by various organellae of attachment (Fig, 

 208). These trophozoites become detached later from the host cells 

 and move about in the lumen of the gut. This stage, sporadin, is ordi- 

 narily most frequently recognized. It is usually large and vermiform. 



Fig. 201. The life-cycle of Lankesteria culicis, X about 500 (Wen- 

 yon), a, entrance of sporozoites into the epithelial cell and growth stages 

 of trophozoite; b, mature trophozoite; c, association of two trophozoites; 

 d-f, gamete-formation; g, zygote-formation; h, development of spores 

 from zygotes; i, a spore; j, germination of spore in host gut. 



The body is covered by a definite pellicle and its cytoplasm is clearly 

 differentiated into the ectoplasm and endoplasm. The former con- 

 tains myonemes (p. 54) which enable the organisms to undergo glid- 

 ing movements. 



In one group, Acephalina, the body is of a single compartment, 

 but in the other group, Cephalina, the body is divided into two com- 

 partments by an ectoplasmic septum. The smaller anterior part 

 is the protomerite and the larger posterior part, the deutomerite, 

 contains a single nucleus. In Pileocephalus the nucleus is said 

 to be located in the protomerite and according to Goodrich (1938) 

 both the protomerite and deutomerite of Nina gracilis contain 



