730 



OEDEE: MYXOSPOEIDIIDA 



Sphaeromyxa sabrazesi Laveran and Mesnil, 1900.^ — This parasite 

 was discovered in tlie gall bladder of the sea-horse, Hijjpocamqnis hrevi- 

 rostris, by Laveran and Mesnil (1900). Schroder (1907, 1910) studied its 

 development in the gall bladder of H. guttulatus. It lives in the gall 

 bladder and larger bile ducts as a more or less circular disc of cytoplasm, 

 which may reach a diameter of half a centimetre. There is a definite 

 hyaline ectoplasm and a much vacuolated endoplasm, in which numerous 

 retractile granules are embedded. It is probable that infection is com- 



FiG. 309. 



-Spore Formation in Sphceromyxa sabrazesi (x ca. 1,500). 

 (After Schroder, 1907 and 1910.) 



A. Pro i^agative cell with two nuclei. B. Union of two propagative cells. 



C. Cell with four nuclei, two small nuclei of envelope cells, and two large nuclei, which contribute 



to the formation of two spores . 



D. Division of the cell after nuclear multiplication into two spore-forming bodies. Each 



contains six nuclei and two commencing polar capsules. At the centre are two residual 

 nuclei. E. Two sj^ores nearing comjjletion. 



F. Complete spore before union of two nuclei in the sporoplasm. 



G. Two nuclei of sporoplasm have united. 



menced by the small uninucleate amoeboid body which, escaping from 

 the spore in the intestine of the fish, invades the bile ducts. By nuclear 

 multiplication and growth of the cytoplasm the large plasmodia are 

 produced. Spore formation commences by the separation of one of the 

 nuclei with some cytoplasm as a small cell, which remains in the cytoplasm 

 of the parent (Fig. 309). The nucleus of this cell divides into a large 

 and a small nucleus, and, as in the case of Myxoholus j^feiffefi, two such 

 binucleate cells become fused into a single quadrinucleate cell, which 

 contains two large and two small nuclei. This cell gives rise by further 



