SPOROZOON PARASITES OF FISHES. 209 



diseases.) Pfeififer mentions threads attached to these bacilli. A coccus is also occa- 

 sionally found. The presence of bacteria is therefore not necessarily an indication that 

 they are primary as causal agents of disease since M. pfeifjeri is known to be the cause 



of the barbel disease. 



GENERAL CONCLUSIONS. 



I. The sores of Fundidus are usually caused primarily by lesions. These may 

 occasionally be due to parasites such as leeches, distomes, and copepods, but usually 

 to rough handling and carnivorous enemies. 



II. At least four kinds of germs invade these lesions and bring about hypertrophy 

 of the tissue elements and decomposition, namely, two species of bacteria and two species 

 of Myxosporidia. 



III. There is doubt as to the virulence of the bacteria. One species at least is 

 saprophytic. There is no doubt as to the virulence of the Myxosporidia when present. 



IV. Cleanliness, careful feeding, and aeration bring about recovery in practically 

 all injured fish. It can not be claimed that fish which are known to have Myxosporidia 

 are curable. 



V. The trophoplasm of both species of Myxosporidia attacks the muscle fibers, 

 that of the M. ■tnusculi also attacks the gill connective tissue. 



VI. Blood elements, especially nuclei, give rise to abundant artifacts which are 

 closely associated with the parasite involved. 



VII. Sporogenesis of the Myxobolus occur infrequently in the muscle and gill tissues. 



VIII. Multiplicative spores are probably formed in M. musculi in addition to pri- 

 mary sporocytes. 



IX. The myxoplasm of both C. fiindidi and M. musculi are stained with difficulty 

 and are therefore not easily found. 



