SPOROZOON PARASITES OF CERTAIN FISHES IN THE VICINITY 

 OF WOODS HOLE, MASSACHUSETTS. 



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By C. \V. HAHN. 



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While studying the Sporozoa in different species of fish at Woods Hole, Mass., in 

 1909, the myxospore of one was observed in diseased killifish, Fundidus heteroclitus 

 and Fundulus majalis. Additional material was obtained and some special experiments 

 were carried out during the seasons of 1910, 1911, 1912, and 1913, the United States 

 Bureau of Fisheries providing the facihties for this and other similar studies at its 

 Woods Hole biological laboratory. " 



OCCURRENCE OF DISEASE. 



When a number of Fundulus of either of the common species (heteroclitus or 

 majalis) are confined in aquaria for a few days during the warm season, one or more 

 thickened white or pink areas appear upon the integument of some of the fishes. The 

 scales of these patches are more or less loosened. They increase in size and number, and 

 the number of afflicted fishes also increases. The fins when involved become bloody and 

 the fin-rays are exposed. Elsewhere the integument disintegrates and the flesh is laid 

 bare. Considerable excavations into the body muscle are not uncommon. The largest 

 cavity of this kind observed was in the head region, measuring about 10 to 12 mm. in 

 diameter and 2 to 3 mm. in depth. Such excavations expose large areas of the skull. 

 When other parts are attacked, loss of blood or penetration of vital parts causes death 

 before the lesion becomes conspicuous externally. The integument is thickened around 

 the sores where the scales are loose. Its color is pink or white. The scales fall out at 

 the edge of the sores. The caudal fin may be completely removed, also the flesh and 

 integument of the tail, thus exposing the vertebrae, before the fish succumbs to the 

 disease. Fish frequently give evidence of weakness and depression even before the 

 flesh has been exposed. There is nothing peculiar about the locomotion except a dimin- 

 ished activity. In certain cases where there is conspicuous inflammation of the integ- 

 ument, especially under the head, the fish may be observed to dart downward, and, 

 with a slight rotation or twist of the body, to scrape the ventral or lateral portion of 

 the head upon the bottom of the aquarium. The fish slowly lose strength, the smaller 

 ones first, and the larger ones not until they are greatly mutilated. Apparently all 

 afflicted fish die unless special care is given to cleanliness, water, and food. 



The proportion of fish that are diseased when caught has not been ascertained. 

 The ratio of those that develop integumentary sores in the first day or two to those 

 that are healthy depends to a great measure upon the injuries received in handling the 



1 Valuable assistance from Dr. Edward Linton and Mr. Vinal E. Edwards is gratefully acknowledged. 



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