92 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 

 Sporoplasm 



This was noted (but apparently regarded as a third capsule) by Miil- 

 ler,i and it appears iu several of his figures. Subsequently Lieberkiihn ^ 

 observed its exit from the spore and its ainosboid movements. He also 

 notes its visibility within the spore.^ These observations have been 

 confirmed by Balbiani* and later by others (see pp. 2(33, 287). 



The sporoi)lasm is extremely transparent, more or less granular, and 

 contains nuclei (1 or more), sometimes a vacuole, and, at any rate in 

 the genus Myxoholm, a variable number of brightly refringent granules. 



Nuclei. — These were first demonstrated byThelohan.* Their number 

 is variable in the same spore, according to the stage of development. 

 In Myxoholus ellipsoides, Thelohan demonstrated their origin by contin- 

 uous division from a primitive single one. He further says " that all 

 species studied by him (with the possible exception of the Glugea species, 

 in which the small size of the spore prevented accurate determination) 

 have shown 2 nuclei. This accords with my own observations. 



Granules {'■'■ refringent globules," etc.). — These have been noticed in 

 several Myxoholus species. They are described under that genus (see 

 p. 209). 



Vacuole. — This structure is of two types: (1) The noniodine-staining 

 {aniodinoijJiile) vacuole. This is known only in, and forms a marked 

 cliaracteristic of, the Cryptocystes. It is situated in the large extremity 

 of the ovoid or pyriform s])ores and is unaflected by iodine. This 

 structure was first observed, but not at that time recognized as a 

 vacuole, by Thelohan.'^ Subsequently he recognized its true nature.^ 

 (2) The iodine-staining {iodinophile) vacuole. This is known only in, 

 and forms a marked characteristic of, the Myxoholidce. It is stained by 

 iodine dark brown against a light yellow-brown ground. This reaction 

 is best obtained with a dilute solution (aqueous, with potassium iodide). 

 Further details are given under Myxoholus (p. 208). 



' Miiller's Archiv., 1841, p. 484, pi. 16, fig. 3 i, Ic; cf. fig. 5. 



^Miiller's Arcbiv., 1854, pp. 353-4, pi. 14, figs. 7, 8. 



3 Bull, Acad. Roy. Belg., 1854, xxi, pt. 2, p. 21. 



^Compt. Rend. Acad. Sci. Paris, 1863, LVii, p. 160. 



^ Compt. Rend. Acad. Sci. Paris, 1889, cix, pp. 920-21. For Perugia's confirmation, 

 see Myxobolmf merlucii (p. 242). For Biitschli's "nucleus", see p. 219. 



« Compt. Rend, Acad. Sci. Paris, 1892, cxv, p. 1092. 



7 Annal. de Microgr., 1890, ii, p. 211, pi. 1, tig. lla, b. 



« Relative to the homology of the vacuole, Thelohan says : 



" Is there any connection between the central vesicle and the rest of segmentation 

 of the other Sporozoa ? A certain fact is that the aspect of the plasmic mass of the 

 spores of the Myxosporidia with that vesicle refractory to staining, and the nuclei 

 disseminated in the protoplasm, recalls in a striking manner certain phases of devel- 

 opment of the spores of the Gregarines." 



