THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 303 
PLATE 43. 
Figs. 1-5. Myridium lieberkiihnii. 
1. Myxosporidia (after Lieberkiihn. x 1). 
la. Showing the granule-free, pronged end by which attachment is effected, 
and a pansporoblast containing 2 spores. x 330. 
1b. Myxosporidium which has mostly broken up into pansporoblasts. x 900. 
2. Specimen covered with transverse wrinkle-like elevations; at one end some 
pseudopodia (after Biitschli. x #). x 160. 
3. Three successive stages in the development of clear ectoplasmic pseudopodia 
at one end of a large myxosporidium (after Biitschli. x1). 
4, Small myxosporidium attached to a nucleated bladder cell (after Biitschli. 
x<oil 
5. Strongly amcboid-branched specimen (after Biitschli. x $). x about 90. 
PLATE 44, 
Figs. 1-5. Myzxidium lieberkiihnii (after Biitschli. x 1). 
la,b. Large forking myxosporidia; a, with fine hair-like ectoplasmic pro- 
cesses, 
2. Large myxosporidium, showing interlaminw between ectoplasm and endo- 
plasm. 
3. Portion of border of myxosporidium showing the peculiar canaliculate struc- 
ture mentioned on p. 285. 
4. Part of border of large myxosporidium with branched horn-like ectoplasmic 
processes. 
5a-d. Four yellowish fat globules, inclosing hematoidin crystals. 
PuLatTEr 45. 
Figs. 1-3. Myxidium lieberkiihnii (after Pfeiffer. x 1). 
la. Smallest form. 
1b. Small form with fat globules, hematoidin crystals, with only 1 pair of 
ripened spores; ectoplasm evident. 
le. Motile myxosporidium with very strong soap-bubble-like ectoplasm; in its 
interior a well-preserved red blood corpuscle, with fat globules and hema- 
toidin inclusions. 
1d. Specimen with amceboid pseudopodia. 
le, f. Large forms with scattered spores. 
1g. Carmine staining after removal of fat by chloroform; the whole endoplasm 
riddled with nuclei, As yet without spores. 
ih. Isolated spore x 1200. 
2,1. Superficial epithelial layer; 6 healthy epithelial cells with nuclei, and 2 
separate strongly hypertrophied cells in which, very soon after infection, 
the nucleus is destroyed. 
2, Ila. Myxosporidium fallen out of epithelial cell. Still without ectoplasm. 
b. Young form, free in urine with peculiar pseudopodioid motile ectoplasmie 
processes extruded and retracted on a slightly warm stage and many fat 
globules in the endoplasm. 
2, Ila. Pansporoblast formation; a, small myxosporidium with bristle processes. 
b. Sexanucleate pansporoblasts, which later form 2 trinucleate sporoblasts; 
in each sporoblast 2 nuclei form the capsules, the third the sporoplasm (fide 
Pfeiffer). 
3. Transverse section of urinary bladder of pike, aleohol-hardened, celloidin- 
imbedded, hematoxylin-stained. 
Sa. Showing, from right to left, the external muscle layer, the internal muscle 
layer cut transversely, the submucosa, the epithelium with infection in the 
superficial layers, and free brown-colored myxosporidia containing hema- 
toidin and sporoblasts. xX 80. 
3b. Portion of a. To the right the monstrously appearing myxosporidia and 
sporoblasts. x 400. 
3c. Natural size of the bladder section, 
