THE SPOROZOA 



297 



Spores minute, pear-shaped, with one polar capsule, which is only visible 

 after treatment with reagents (Fig. 1 1 3). More than two spores are formed 

 in each pansporoblast. Cell parasites. 



FAMILY 5. GLUGEIDAE, Thelohan. With the characters of the sub- 

 order. 



Section a. Polysporogenea, Doflein. The trophozoite produces numerous 

 pansporoblasts, each of which in turn produces many spores. 



Genus 13. Glugea, The!., 1891. With characters of the section. (The 

 synonymy of this genus is somewhat involved, and it is by no means 

 certain that the name most commonly employed has the prior right over 

 Nosema, Ntigeli, 1857, or Microsporidium, Balbiani.) A large number of 

 species are known, from a great variety of hosts, among which Arthropods 

 and Fishes preponderate. The best known species is the destructive 

 G. bombycis of the silkworm. 



Section (3. Oligosporogeuea, Doflein. 

 The trophozoite produces a single pan- 

 sporoblast. 



Genus 14. Gurleya, Doilein, 1898. 

 The pansporoblast produces four 

 spores. One species known, G. tetra- 

 spora, Don., from the hypodermic 

 tissue of Daphnia maxima at Munich. 

 Genus 15. Thelohania, Henn., 1892. 

 The pansporoblast produces eight 

 spores. Five species known, all from 

 the muscles of Crustacea. Genus 16. 

 Pleistophora, Gurley, 1893. The pan- 

 sporoblast produces numerous spores. 

 P. typicalis, Gurley, muscles of various 

 fishes (Fig. 114); an undescribed 

 species observed in a Trematode 

 (Leger). Many of the numerous 



jtys. 



-m.f. 



Fio. 114. 



species described under the name Portion of a sccti( , n through a muscle 

 Gluqea are referred by Labbe* to this fibre f Cottus scorpius invaded by Pleistophora 



typicalis, Gurley. m.f, muscle fibrils, retain- 

 genus. ing their striation ; myx, cysts of the parasite, 



Myxosporidia (?) incertae sedis. lying between tiie fibrils. 

 Under the name Myxocystis dliata, 



Mrazek (1897 [110]) has described a parasite found in Limnodrilns 

 claparedianus. The parasites in question were only observed in a single 

 instance, occurring in vast numbers, and rendering the host opaque and 

 greyish in appearance. They were found in the wall of the gut or in 

 the body-cavity, as spherical or oval masses, 50 to 100 //, in diameter, 

 often united in groups. They showed a distinct etoplasm, usually 

 prolonged into a fur of delicate filaments, similar to those seen in 

 many Myxosporidia (e.g. Myxidium lieberkiihnii, p. 281). The endoplasm 

 contained nuclei of different sizes, and also spores, the latter sometimes 

 filling up the entire endoplasm. Each spore was oval, 4 /* in length, 

 resembling a spore of Glugea, and contained a strongly refractile body, 

 perhaps a polar capsule. Mrazek considers that Myxocystis shows some 



