FISH PESTS 241 



in classification. Within each vacuole a long, coiled 

 filament is formed, capable of ejection and used for 

 fixation. For the regulation of each polar filament 

 with its polar capsule or vacuole a nucleus is set 

 apart. This latter is the capsulogenous nucleus. 

 Four capsulogenous nuclei occur in the Chloro- 

 myxidae, two in the other members of the group. 

 The general cytoplasm of the spore also is provided 

 with a nucleus, which may divide again, so that the 

 sporoplasm is binucleate. 



The appearance of the spores is very varied in the 

 different groups. The members of one large genus, 

 Myxidium, have very characteristic lemon or lens- 

 shaped spores. Ceratomyxa has flattened, elongate 

 spores, often with long processes or tails. The 

 Leptotheca spores are oblong and squat. Chloro- 

 myxum may have remarkable patternings and fold- 

 ings of its sporocyst. Sphczromyxa has narrow, 

 curved spores. The spore of Henneguya is remark- 

 able for its long, narrow tail, and is suggestive of a 

 tadpole ; while Hoferellus, from the kidney of the carp, 

 bears some slight resemblance to a skate's egg, 

 devoid of coils (the " mermaid's purse " of the sea- 

 shore). 



As previously mentioned, , there are two great 

 divisions of the Myxosporidia, and pathogenic genera 

 are found in each. The Disporea possess two genera, 

 Leptotheca and Ceratomyxa, while the Polysporea 

 embrace seven genera Myxidium, Sphtzrospora with 

 Sph&romyxa, Chloromyxum, Myxobolus, Lentospora 

 Henneguya, and Hoferellus. Among these genera, 

 so far as destructiveness has been concerned, 



