THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 289 



attached firmly to Distoina folium (frequently found in the pike's blad- 

 der); also attached to other myxo.sijoridia. Observed by Biitschli in 

 December. 



All individuals of TAicius from the Khine and Saar have myxospo- 

 ridia in the bladder, while those from the Elbe and Weser territory only 

 exceptionally show them (PfeifiFer, 1891, i). 110). 



Perrier erroneously cites the habitat as the air hladder. 



Pathology (Pfeiff'er). — The coarser anatomical details cau be seen 

 (under 300 or 400 diameters) by carefully stretching a bladder tightly 

 over a cork, placing a cover glass underneath, brief fixation, and hard- 

 ening by alcohol and staining. Control expeiiinents may be made by 

 maceration in diluted acetic acid. The infection of the bladder was 

 also followed by capillary cultures. 



Mucous membrane, when slightly affected, showing individual clusters 

 of 4, 5, 100 or more epithelial cells infected with myxosporidia ; thence 

 all grades of hypertrophy fnp to 10 to 30 times the normal size) can be 

 traced. 



Hypertrophy of epithelial cells: When slight, the cells are swollen, 

 shining, ap[)arently lobed. Pfeiff'er failed to differentiate the nucleus 

 and the intruder, probably owing to early succumbing of the nucleus. 

 With greater hypertrophy the cells are filled with and overdistended 

 by the parasites ; subsequently, continued growth of the myxosporidiam 

 ruptures the cell membrane; the myxosporidium flows amoeboidly out in 

 gi-otesque shapes, and immediately differentiates its hj-aline ectoplasm; 

 rupture of cell membrane visible under the microscope. Ha;matoxylin 

 or phloxinred-methylenblue stains a narrow-bordered, dark globule in 

 the interior of the swollen epithelial cells; nucleus of latter invisible; 

 largest cells indicating, by ragged coloring of contour, the degeneration 

 of the epithelial remains. 



Effects (of this species??). — Of late years dead pike and perch have 

 frequently floated down the Mosel and the Khine. It is doubtful 

 whether the disease here is the same as the muscle infection of the 

 barbel. According to a statement [unpublished, I infer] by Dr. T. W. 

 MUller in Greifswald, the spore found in the flesh of the pike is not the 

 same as that of the barbel, but is formed upon the type of M. lieher- 

 Mhnii (Pfeiff'er).^ 



Whether the pike and perch in the Mosel die from myxosporidiosis is 

 unknown With the perch, fungous disease concurs (Ludwig).^ 

 101. Myxidium ? ? incurvatum Th^lohan, 1892. 



Coijipt. Rend. Acad. Sci. Paris, cxv, pp. 1093-1094. 



Cyst, probably none. 



Myxosimridium.—Hmail], feebly motile. Ectoplasm (in sections) very 

 clearly striate. Pseudopodia lobed, sometimes f jrming a bristly, shaggy 

 coat, as in Myxidium lieberkuhnii. 



'Die Protozoea als Krankheitserreger, 1892, 2 eA., p. 10.5. 

 ^Jahresber. d. rhein. Fiscb.-Vereiiis Bonn, 1888, i>p. 27, 28. 

 F C 19 



